kernel/fs/btrfs/volumes.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/slab.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/random.h>
  24 #include <linux/iocontext.h>
  25 #include <linux/capability.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include <linux/raid/pq.h>
  29 #include <linux/semaphore.h>
  30 #include <asm/div64.h>
  31 #include "ctree.h"
  32 #include "extent_map.h"
  33 #include "disk-io.h"
  34 #include "transaction.h"
  35 #include "print-tree.h"
  36 #include "volumes.h"
  37 #include "raid56.h"
  38 #include "async-thread.h"
  39 #include "check-integrity.h"
  40 #include "rcu-string.h"
  41 #include "math.h"
  42 #include "dev-replace.h"
  43 #include "sysfs.h"
  44
  45 const struct btrfs_raid_attr btrfs_raid_array[BTRFS_NR_RAID_TYPES] = {
  46         [BTRFS_RAID_RAID10] = {
  47                 .sub_stripes    = 2,
  48                 .dev_stripes    = 1,
  49                 .devs_max       = 0,    /* 0 == as many as possible */
  50                 .devs_min       = 4,
  51                 .tolerated_failures = 1,
  52                 .devs_increment = 2,
  53                 .ncopies        = 2,
  54         },
  55         [BTRFS_RAID_RAID1] = {
  56                 .sub_stripes    = 1,
  57                 .dev_stripes    = 1,
  58                 .devs_max       = 2,
  59                 .devs_min       = 2,
  60                 .tolerated_failures = 1,
  61                 .devs_increment = 2,
  62                 .ncopies        = 2,
  63         },
  64         [BTRFS_RAID_DUP] = {
  65                 .sub_stripes    = 1,
  66                 .dev_stripes    = 2,
  67                 .devs_max       = 1,
  68                 .devs_min       = 1,
  69                 .tolerated_failures = 0,
  70                 .devs_increment = 1,
  71                 .ncopies        = 2,
  72         },
  73         [BTRFS_RAID_RAID0] = {
  74                 .sub_stripes    = 1,
  75                 .dev_stripes    = 1,
  76                 .devs_max       = 0,
  77                 .devs_min       = 2,
  78                 .tolerated_failures = 0,
  79                 .devs_increment = 1,
  80                 .ncopies        = 1,
  81         },
  82         [BTRFS_RAID_SINGLE] = {
  83                 .sub_stripes    = 1,
  84                 .dev_stripes    = 1,
  85                 .devs_max       = 1,
  86                 .devs_min       = 1,
  87                 .tolerated_failures = 0,
  88                 .devs_increment = 1,
  89                 .ncopies        = 1,
  90         },
  91         [BTRFS_RAID_RAID5] = {
  92                 .sub_stripes    = 1,
  93                 .dev_stripes    = 1,
  94                 .devs_max       = 0,
  95                 .devs_min       = 2,
  96                 .tolerated_failures = 1,
  97                 .devs_increment = 1,
  98                 .ncopies        = 2,
  99         },
 100         [BTRFS_RAID_RAID6] = {
 101                 .sub_stripes    = 1,
 102                 .dev_stripes    = 1,
 103                 .devs_max       = 0,
 104                 .devs_min       = 3,
 105                 .tolerated_failures = 2,
 106                 .devs_increment = 1,
 107                 .ncopies        = 3,
 108         },
 109 };
 110
 111 const u64 const btrfs_raid_group[BTRFS_NR_RAID_TYPES] = {
 112         [BTRFS_RAID_RAID10] = BTRFS_BLOCK_GROUP_RAID10,
 113         [BTRFS_RAID_RAID1]  = BTRFS_BLOCK_GROUP_RAID1,
 114         [BTRFS_RAID_DUP]    = BTRFS_BLOCK_GROUP_DUP,
 115         [BTRFS_RAID_RAID0]  = BTRFS_BLOCK_GROUP_RAID0,
 116         [BTRFS_RAID_SINGLE] = 0,
 117         [BTRFS_RAID_RAID5]  = BTRFS_BLOCK_GROUP_RAID5,
 118         [BTRFS_RAID_RAID6]  = BTRFS_BLOCK_GROUP_RAID6,
 119 };
 120
 121 static int init_first_rw_device(struct btrfs_trans_handle *trans,
 122                                 struct btrfs_root *root,
 123                                 struct btrfs_device *device);
 124 static int btrfs_relocate_sys_chunks(struct btrfs_root *root);
 125 static void __btrfs_reset_dev_stats(struct btrfs_device *dev);
 126 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev);
 127 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
 128
 129 DEFINE_MUTEX(uuid_mutex);
 130 static LIST_HEAD(fs_uuids);
 131 struct list_head *btrfs_get_fs_uuids(void)
 132 {
 133         return &fs_uuids;
 134 }
 135
 136 static struct btrfs_fs_devices *__alloc_fs_devices(void)
 137 {
 138         struct btrfs_fs_devices *fs_devs;
 139
 140         fs_devs = kzalloc(sizeof(*fs_devs), GFP_NOFS);
 141         if (!fs_devs)
 142                 return ERR_PTR(-ENOMEM);
 143
 144         mutex_init(&fs_devs->device_list_mutex);
 145
 146         INIT_LIST_HEAD(&fs_devs->devices);
 147         INIT_LIST_HEAD(&fs_devs->resized_devices);
 148         INIT_LIST_HEAD(&fs_devs->alloc_list);
 149         INIT_LIST_HEAD(&fs_devs->list);
 150
 151         return fs_devs;
 152 }
 153
 154 /**
 155  * alloc_fs_devices - allocate struct btrfs_fs_devices
 156  * @fsid:       a pointer to UUID for this FS.  If NULL a new UUID is
 157  *              generated.
 158  *
 159  * Return: a pointer to a new &struct btrfs_fs_devices on success;
 160  * ERR_PTR() on error.  Returned struct is not linked onto any lists and
 161  * can be destroyed with kfree() right away.
 162  */
 163 static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)
 164 {
 165         struct btrfs_fs_devices *fs_devs;
 166
 167         fs_devs = __alloc_fs_devices();
 168         if (IS_ERR(fs_devs))
 169                 return fs_devs;
 170
 171         if (fsid)
 172                 memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);
 173         else
 174                 generate_random_uuid(fs_devs->fsid);
 175
 176         return fs_devs;
 177 }
 178
 179 static void free_fs_devices(struct btrfs_fs_devices *fs_devices)
 180 {
 181         struct btrfs_device *device;
 182         WARN_ON(fs_devices->opened);
 183         while (!list_empty(&fs_devices->devices)) {
 184                 device = list_entry(fs_devices->devices.next,
 185                                     struct btrfs_device, dev_list);
 186                 list_del(&device->dev_list);
 187                 rcu_string_free(device->name);
 188                 kfree(device);
 189         }
 190         kfree(fs_devices);
 191 }
 192
 193 static void btrfs_kobject_uevent(struct block_device *bdev,
 194                                  enum kobject_action action)
 195 {
 196         int ret;
 197
 198         ret = kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, action);
 199         if (ret)
 200                 pr_warn("BTRFS: Sending event '%d' to kobject: '%s' (%p): failed\n",
 201                         action,
 202                         kobject_name(&disk_to_dev(bdev->bd_disk)->kobj),
 203                         &disk_to_dev(bdev->bd_disk)->kobj);
 204 }
 205
 206 void btrfs_cleanup_fs_uuids(void)
 207 {
 208         struct btrfs_fs_devices *fs_devices;
 209
 210         while (!list_empty(&fs_uuids)) {
 211                 fs_devices = list_entry(fs_uuids.next,
 212                                         struct btrfs_fs_devices, list);
 213                 list_del(&fs_devices->list);
 214                 free_fs_devices(fs_devices);
 215         }
 216 }
 217
 218 static struct btrfs_device *__alloc_device(void)
 219 {
 220         struct btrfs_device *dev;
 221
 222         dev = kzalloc(sizeof(*dev), GFP_NOFS);
 223         if (!dev)
 224                 return ERR_PTR(-ENOMEM);
 225
 226         INIT_LIST_HEAD(&dev->dev_list);
 227         INIT_LIST_HEAD(&dev->dev_alloc_list);
 228         INIT_LIST_HEAD(&dev->resized_list);
 229
 230         spin_lock_init(&dev->io_lock);
 231
 232         spin_lock_init(&dev->reada_lock);
 233         atomic_set(&dev->reada_in_flight, 0);
 234         atomic_set(&dev->dev_stats_ccnt, 0);
 235         btrfs_device_data_ordered_init(dev);
 236         INIT_RADIX_TREE(&dev->reada_zones, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 237         INIT_RADIX_TREE(&dev->reada_extents, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
 238
 239         return dev;
 240 }
 241
 242 static noinline struct btrfs_device *__find_device(struct list_head *head,
 243                                                    u64 devid, u8 *uuid)
 244 {
 245         struct btrfs_device *dev;
 246
 247         list_for_each_entry(dev, head, dev_list) {
 248                 if (dev->devid == devid &&
 249                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
 250                         return dev;
 251                 }
 252         }
 253         return NULL;
 254 }
 255
 256 static noinline struct btrfs_fs_devices *find_fsid(u8 *fsid)
 257 {
 258         struct btrfs_fs_devices *fs_devices;
 259
 260         list_for_each_entry(fs_devices, &fs_uuids, list) {
 261                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 262                         return fs_devices;
 263         }
 264         return NULL;
 265 }
 266
 267 static int
 268 btrfs_get_bdev_and_sb(const char *device_path, fmode_t flags, void *holder,
 269                       int flush, struct block_device **bdev,
 270                       struct buffer_head **bh)
 271 {
 272         int ret;
 273
 274         *bdev = blkdev_get_by_path(device_path, flags, holder);
 275
 276         if (IS_ERR(*bdev)) {
 277                 ret = PTR_ERR(*bdev);
 278                 goto error;
 279         }
 280
 281         if (flush)
 282                 filemap_write_and_wait((*bdev)->bd_inode->i_mapping);
 283         ret = set_blocksize(*bdev, 4096);
 284         if (ret) {
 285                 blkdev_put(*bdev, flags);
 286                 goto error;
 287         }
 288         invalidate_bdev(*bdev);
 289         *bh = btrfs_read_dev_super(*bdev);
 290         if (IS_ERR(*bh)) {
 291                 ret = PTR_ERR(*bh);
 292                 blkdev_put(*bdev, flags);
 293                 goto error;
 294         }
 295
 296         return 0;
 297
 298 error:
 299         *bdev = NULL;
 300         *bh = NULL;
 301         return ret;
 302 }
 303
 304 static void requeue_list(struct btrfs_pending_bios *pending_bios,
 305                         struct bio *head, struct bio *tail)
 306 {
 307
 308         struct bio *old_head;
 309
 310         old_head = pending_bios->head;
 311         pending_bios->head = head;
 312         if (pending_bios->tail)
 313                 tail->bi_next = old_head;
 314         else
 315                 pending_bios->tail = tail;
 316 }
 317
 318 /*
 319  * we try to collect pending bios for a device so we don't get a large
 320  * number of procs sending bios down to the same device.  This greatly
 321  * improves the schedulers ability to collect and merge the bios.
 322  *
 323  * But, it also turns into a long list of bios to process and that is sure
 324  * to eventually make the worker thread block.  The solution here is to
 325  * make some progress and then put this work struct back at the end of
 326  * the list if the block device is congested.  This way, multiple devices
 327  * can make progress from a single worker thread.
 328  */
 329 static noinline void run_scheduled_bios(struct btrfs_device *device)
 330 {
 331         struct bio *pending;
 332         struct backing_dev_info *bdi;
 333         struct btrfs_fs_info *fs_info;
 334         struct btrfs_pending_bios *pending_bios;
 335         struct bio *tail;
 336         struct bio *cur;
 337         int again = 0;
 338         unsigned long num_run;
 339         unsigned long batch_run = 0;
 340         unsigned long limit;
 341         unsigned long last_waited = 0;
 342         int force_reg = 0;
 343         int sync_pending = 0;
 344         struct blk_plug plug;
 345
 346         /*
 347          * this function runs all the bios we've collected for
 348          * a particular device.  We don't want to wander off to
 349          * another device without first sending all of these down.
 350          * So, setup a plug here and finish it off before we return
 351          */
 352         blk_start_plug(&plug);
 353
 354         bdi = blk_get_backing_dev_info(device->bdev);
 355         fs_info = device->dev_root->fs_info;
 356         limit = btrfs_async_submit_limit(fs_info);
 357         limit = limit * 2 / 3;
 358
 359 loop:
 360         spin_lock(&device->io_lock);
 361
 362 loop_lock:
 363         num_run = 0;
 364
 365         /* take all the bios off the list at once and process them
 366          * later on (without the lock held).  But, remember the
 367          * tail and other pointers so the bios can be properly reinserted
 368          * into the list if we hit congestion
 369          */
 370         if (!force_reg && device->pending_sync_bios.head) {
 371                 pending_bios = &device->pending_sync_bios;
 372                 force_reg = 1;
 373         } else {
 374                 pending_bios = &device->pending_bios;
 375                 force_reg = 0;
 376         }
 377
 378         pending = pending_bios->head;
 379         tail = pending_bios->tail;
 380         WARN_ON(pending && !tail);
 381
 382         /*
 383          * if pending was null this time around, no bios need processing
 384          * at all and we can stop.  Otherwise it'll loop back up again
 385          * and do an additional check so no bios are missed.
 386          *
 387          * device->running_pending is used to synchronize with the
 388          * schedule_bio code.
 389          */
 390         if (device->pending_sync_bios.head == NULL &&
 391             device->pending_bios.head == NULL) {
 392                 again = 0;
 393                 device->running_pending = 0;
 394         } else {
 395                 again = 1;
 396                 device->running_pending = 1;
 397         }
 398
 399         pending_bios->head = NULL;
 400         pending_bios->tail = NULL;
 401
 402         spin_unlock(&device->io_lock);
 403
 404         while (pending) {
 405
 406                 rmb();
 407                 /* we want to work on both lists, but do more bios on the
 408                  * sync list than the regular list
 409                  */
 410                 if ((num_run > 32 &&
 411                     pending_bios != &device->pending_sync_bios &&
 412                     device->pending_sync_bios.head) ||
 413                    (num_run > 64 && pending_bios == &device->pending_sync_bios &&
 414                     device->pending_bios.head)) {
 415                         spin_lock(&device->io_lock);
 416                         requeue_list(pending_bios, pending, tail);
 417                         goto loop_lock;
 418                 }
 419
 420                 cur = pending;
 421                 pending = pending->bi_next;
 422                 cur->bi_next = NULL;
 423
 424                 /*
 425                  * atomic_dec_return implies a barrier for waitqueue_active
 426                  */
 427                 if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&
 428                     waitqueue_active(&fs_info->async_submit_wait))
 429                         wake_up(&fs_info->async_submit_wait);
 430
 431                 BUG_ON(atomic_read(&cur->__bi_cnt) == 0);
 432
 433                 /*
 434                  * if we're doing the sync list, record that our
 435                  * plug has some sync requests on it
 436                  *
 437                  * If we're doing the regular list and there are
 438                  * sync requests sitting around, unplug before
 439                  * we add more
 440                  */
 441                 if (pending_bios == &device->pending_sync_bios) {
 442                         sync_pending = 1;
 443                 } else if (sync_pending) {
 444                         blk_finish_plug(&plug);
 445                         blk_start_plug(&plug);
 446                         sync_pending = 0;
 447                 }
 448
 449                 btrfsic_submit_bio(cur->bi_rw, cur);
 450                 num_run++;
 451                 batch_run++;
 452
 453                 cond_resched();
 454
 455                 /*
 456                  * we made progress, there is more work to do and the bdi
 457                  * is now congested.  Back off and let other work structs
 458                  * run instead
 459                  */
 460                 if (pending && bdi_write_congested(bdi) && batch_run > 8 &&
 461                     fs_info->fs_devices->open_devices > 1) {
 462                         struct io_context *ioc;
 463
 464                         ioc = current->io_context;
 465
 466                         /*
 467                          * the main goal here is that we don't want to
 468                          * block if we're going to be able to submit
 469                          * more requests without blocking.
 470                          *
 471                          * This code does two great things, it pokes into
 472                          * the elevator code from a filesystem _and_
 473                          * it makes assumptions about how batching works.
 474                          */
 475                         if (ioc && ioc->nr_batch_requests > 0 &&
 476                             time_before(jiffies, ioc->last_waited + HZ/50UL) &&
 477                             (last_waited == 0 ||
 478                              ioc->last_waited == last_waited)) {
 479                                 /*
 480                                  * we want to go through our batch of
 481                                  * requests and stop.  So, we copy out
 482                                  * the ioc->last_waited time and test
 483                                  * against it before looping
 484                                  */
 485                                 last_waited = ioc->last_waited;
 486                                 cond_resched();
 487                                 continue;
 488                         }
 489                         spin_lock(&device->io_lock);
 490                         requeue_list(pending_bios, pending, tail);
 491                         device->running_pending = 1;
 492
 493                         spin_unlock(&device->io_lock);
 494                         btrfs_queue_work(fs_info->submit_workers,
 495                                          &device->work);
 496                         goto done;
 497                 }
 498                 /* unplug every 64 requests just for good measure */
 499                 if (batch_run % 64 == 0) {
 500                         blk_finish_plug(&plug);
 501                         blk_start_plug(&plug);
 502                         sync_pending = 0;
 503                 }
 504         }
 505
 506         cond_resched();
 507         if (again)
 508                 goto loop;
 509
 510         spin_lock(&device->io_lock);
 511         if (device->pending_bios.head || device->pending_sync_bios.head)
 512                 goto loop_lock;
 513         spin_unlock(&device->io_lock);
 514
 515 done:
 516         blk_finish_plug(&plug);
 517 }
 518
 519 static void pending_bios_fn(struct btrfs_work *work)
 520 {
 521         struct btrfs_device *device;
 522
 523         device = container_of(work, struct btrfs_device, work);
 524         run_scheduled_bios(device);
 525 }
 526
 527
 528 void btrfs_free_stale_device(struct btrfs_device *cur_dev)
 529 {
 530         struct btrfs_fs_devices *fs_devs;
 531         struct btrfs_device *dev;
 532
 533         if (!cur_dev->name)
 534                 return;
 535
 536         list_for_each_entry(fs_devs, &fs_uuids, list) {
 537                 int del = 1;
 538
 539                 if (fs_devs->opened)
 540                         continue;
 541                 if (fs_devs->seeding)
 542                         continue;
 543
 544                 list_for_each_entry(dev, &fs_devs->devices, dev_list) {
 545
 546                         if (dev == cur_dev)
 547                                 continue;
 548                         if (!dev->name)
 549                                 continue;
 550
 551                         /*
 552                          * Todo: This won't be enough. What if the same device
 553                          * comes back (with new uuid and) with its mapper path?
 554                          * But for now, this does help as mostly an admin will
 555                          * either use mapper or non mapper path throughout.
 556                          */
 557                         rcu_read_lock();
 558                         del = strcmp(rcu_str_deref(dev->name),
 559                                                 rcu_str_deref(cur_dev->name));
 560                         rcu_read_unlock();
 561                         if (!del)
 562                                 break;
 563                 }
 564
 565                 if (!del) {
 566                         /* delete the stale device */
 567                         if (fs_devs->num_devices == 1) {
 568                                 btrfs_sysfs_remove_fsid(fs_devs);
 569                                 list_del(&fs_devs->list);
 570                                 free_fs_devices(fs_devs);
 571                         } else {
 572                                 fs_devs->num_devices--;
 573                                 list_del(&dev->dev_list);
 574                                 rcu_string_free(dev->name);
 575                                 kfree(dev);
 576                         }
 577                         break;
 578                 }
 579         }
 580 }
 581
 582 /*
 583  * Add new device to list of registered devices
 584  *
 585  * Returns:
 586  * 1   - first time device is seen
 587  * 0   - device already known
 588  * < 0 - error
 589  */
 590 static noinline int device_list_add(const char *path,
 591                            struct btrfs_super_block *disk_super,
 592                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 593 {
 594         struct btrfs_device *device;
 595         struct btrfs_fs_devices *fs_devices;
 596         struct rcu_string *name;
 597         int ret = 0;
 598         u64 found_transid = btrfs_super_generation(disk_super);
 599
 600         fs_devices = find_fsid(disk_super->fsid);
 601         if (!fs_devices) {
 602                 fs_devices = alloc_fs_devices(disk_super->fsid);
 603                 if (IS_ERR(fs_devices))
 604                         return PTR_ERR(fs_devices);
 605
 606                 list_add(&fs_devices->list, &fs_uuids);
 607
 608                 device = NULL;
 609         } else {
 610                 device = __find_device(&fs_devices->devices, devid,
 611                                        disk_super->dev_item.uuid);
 612         }
 613
 614         if (!device) {
 615                 if (fs_devices->opened)
 616                         return -EBUSY;
 617
 618                 device = btrfs_alloc_device(NULL, &devid,
 619                                             disk_super->dev_item.uuid);
 620                 if (IS_ERR(device)) {
 621                         /* we can safely leave the fs_devices entry around */
 622                         return PTR_ERR(device);
 623                 }
 624
 625                 name = rcu_string_strdup(path, GFP_NOFS);
 626                 if (!name) {
 627                         kfree(device);
 628                         return -ENOMEM;
 629                 }
 630                 rcu_assign_pointer(device->name, name);
 631
 632                 mutex_lock(&fs_devices->device_list_mutex);
 633                 list_add_rcu(&device->dev_list, &fs_devices->devices);
 634                 fs_devices->num_devices++;
 635                 mutex_unlock(&fs_devices->device_list_mutex);
 636
 637                 ret = 1;
 638                 device->fs_devices = fs_devices;
 639         } else if (!device->name || strcmp(device->name->str, path)) {
 640                 /*
 641                  * When FS is already mounted.
 642                  * 1. If you are here and if the device->name is NULL that
 643                  *    means this device was missing at time of FS mount.
 644                  * 2. If you are here and if the device->name is different
 645                  *    from 'path' that means either
 646                  *      a. The same device disappeared and reappeared with
 647                  *         different name. or
 648                  *      b. The missing-disk-which-was-replaced, has
 649                  *         reappeared now.
 650                  *
 651                  * We must allow 1 and 2a above. But 2b would be a spurious
 652                  * and unintentional.
 653                  *
 654                  * Further in case of 1 and 2a above, the disk at 'path'
 655                  * would have missed some transaction when it was away and
 656                  * in case of 2a the stale bdev has to be updated as well.
 657                  * 2b must not be allowed at all time.
 658                  */
 659
 660                 /*
 661                  * For now, we do allow update to btrfs_fs_device through the
 662                  * btrfs dev scan cli after FS has been mounted.  We're still
 663                  * tracking a problem where systems fail mount by subvolume id
 664                  * when we reject replacement on a mounted FS.
 665                  */
 666                 if (!fs_devices->opened && found_transid < device->generation) {
 667                         /*
 668                          * That is if the FS is _not_ mounted and if you
 669                          * are here, that means there is more than one
 670                          * disk with same uuid and devid.We keep the one
 671                          * with larger generation number or the last-in if
 672                          * generation are equal.
 673                          */
 674                         return -EEXIST;
 675                 }
 676
 677                 name = rcu_string_strdup(path, GFP_NOFS);
 678                 if (!name)
 679                         return -ENOMEM;
 680                 rcu_string_free(device->name);
 681                 rcu_assign_pointer(device->name, name);
 682                 if (device->missing) {
 683                         fs_devices->missing_devices--;
 684                         device->missing = 0;
 685                 }
 686         }
 687
 688         /*
 689          * Unmount does not free the btrfs_device struct but would zero
 690          * generation along with most of the other members. So just update
 691          * it back. We need it to pick the disk with largest generation
 692          * (as above).
 693          */
 694         if (!fs_devices->opened)
 695                 device->generation = found_transid;
 696
 697         /*
 698          * if there is new btrfs on an already registered device,
 699          * then remove the stale device entry.
 700          */
 701         btrfs_free_stale_device(device);
 702
 703         *fs_devices_ret = fs_devices;
 704
 705         return ret;
 706 }
 707
 708 static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
 709 {
 710         struct btrfs_fs_devices *fs_devices;
 711         struct btrfs_device *device;
 712         struct btrfs_device *orig_dev;
 713
 714         fs_devices = alloc_fs_devices(orig->fsid);
 715         if (IS_ERR(fs_devices))
 716                 return fs_devices;
 717
 718         mutex_lock(&orig->device_list_mutex);
 719         fs_devices->total_devices = orig->total_devices;
 720
 721         /* We have held the volume lock, it is safe to get the devices. */
 722         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
 723                 struct rcu_string *name;
 724
 725                 device = btrfs_alloc_device(NULL, &orig_dev->devid,
 726                                             orig_dev->uuid);
 727                 if (IS_ERR(device))
 728                         goto error;
 729
 730                 /*
 731                  * This is ok to do without rcu read locked because we hold the
 732                  * uuid mutex so nothing we touch in here is going to disappear.
 733                  */
 734                 if (orig_dev->name) {
 735                         name = rcu_string_strdup(orig_dev->name->str, GFP_NOFS);
 736                         if (!name) {
 737                                 kfree(device);
 738                                 goto error;
 739                         }
 740                         rcu_assign_pointer(device->name, name);
 741                 }
 742
 743                 list_add(&device->dev_list, &fs_devices->devices);
 744                 device->fs_devices = fs_devices;
 745                 fs_devices->num_devices++;
 746         }
 747         mutex_unlock(&orig->device_list_mutex);
 748         return fs_devices;
 749 error:
 750         mutex_unlock(&orig->device_list_mutex);
 751         free_fs_devices(fs_devices);
 752         return ERR_PTR(-ENOMEM);
 753 }
 754
 755 void btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices, int step)
 756 {
 757         struct btrfs_device *device, *next;
 758         struct btrfs_device *latest_dev = NULL;
 759
 760         mutex_lock(&uuid_mutex);
 761 again:
 762         /* This is the initialized path, it is safe to release the devices. */
 763         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
 764                 if (device->in_fs_metadata) {
 765                         if (!device->is_tgtdev_for_dev_replace &&
 766                             (!latest_dev ||
 767                              device->generation > latest_dev->generation)) {
 768                                 latest_dev = device;
 769                         }
 770                         continue;
 771                 }
 772
 773                 if (device->devid == BTRFS_DEV_REPLACE_DEVID) {
 774                         /*
 775                          * In the first step, keep the device which has
 776                          * the correct fsid and the devid that is used
 777                          * for the dev_replace procedure.
 778                          * In the second step, the dev_replace state is
 779                          * read from the device tree and it is known
 780                          * whether the procedure is really active or
 781                          * not, which means whether this device is
 782                          * used or whether it should be removed.
 783                          */
 784                         if (step == 0 || device->is_tgtdev_for_dev_replace) {
 785                                 continue;
 786                         }
 787                 }
 788                 if (device->bdev) {
 789                         blkdev_put(device->bdev, device->mode);
 790                         device->bdev = NULL;
 791                         fs_devices->open_devices--;
 792                 }
 793                 if (device->writeable) {
 794                         list_del_init(&device->dev_alloc_list);
 795                         device->writeable = 0;
 796                         if (!device->is_tgtdev_for_dev_replace)
 797                                 fs_devices->rw_devices--;
 798                 }
 799                 list_del_init(&device->dev_list);
 800                 fs_devices->num_devices--;
 801                 rcu_string_free(device->name);
 802                 kfree(device);
 803         }
 804
 805         if (fs_devices->seed) {
 806                 fs_devices = fs_devices->seed;
 807                 goto again;
 808         }
 809
 810         fs_devices->latest_bdev = latest_dev->bdev;
 811
 812         mutex_unlock(&uuid_mutex);
 813 }
 814
 815 static void __free_device(struct work_struct *work)
 816 {
 817         struct btrfs_device *device;
 818
 819         device = container_of(work, struct btrfs_device, rcu_work);
 820
 821         if (device->bdev)
 822                 blkdev_put(device->bdev, device->mode);
 823
 824         rcu_string_free(device->name);
 825         kfree(device);
 826 }
 827
 828 static void free_device(struct rcu_head *head)
 829 {
 830         struct btrfs_device *device;
 831
 832         device = container_of(head, struct btrfs_device, rcu);
 833
 834         INIT_WORK(&device->rcu_work, __free_device);
 835         schedule_work(&device->rcu_work);
 836 }
 837
 838 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 839 {
 840         struct btrfs_device *device, *tmp;
 841
 842         if (--fs_devices->opened > 0)
 843                 return 0;
 844
 845         mutex_lock(&fs_devices->device_list_mutex);
 846         list_for_each_entry_safe(device, tmp, &fs_devices->devices, dev_list) {
 847                 btrfs_close_one_device(device);
 848         }
 849         mutex_unlock(&fs_devices->device_list_mutex);
 850
 851         WARN_ON(fs_devices->open_devices);
 852         WARN_ON(fs_devices->rw_devices);
 853         fs_devices->opened = 0;
 854         fs_devices->seeding = 0;
 855
 856         return 0;
 857 }
 858
 859 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 860 {
 861         struct btrfs_fs_devices *seed_devices = NULL;
 862         int ret;
 863
 864         mutex_lock(&uuid_mutex);
 865         ret = __btrfs_close_devices(fs_devices);
 866         if (!fs_devices->opened) {
 867                 seed_devices = fs_devices->seed;
 868                 fs_devices->seed = NULL;
 869         }
 870         mutex_unlock(&uuid_mutex);
 871
 872         while (seed_devices) {
 873                 fs_devices = seed_devices;
 874                 seed_devices = fs_devices->seed;
 875                 __btrfs_close_devices(fs_devices);
 876                 free_fs_devices(fs_devices);
 877         }
 878         /*
 879          * Wait for rcu kworkers under __btrfs_close_devices
 880          * to finish all blkdev_puts so device is really
 881          * free when umount is done.
 882          */
 883         rcu_barrier();
 884         return ret;
 885 }
 886
 887 static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 888                                 fmode_t flags, void *holder)
 889 {
 890         struct request_queue *q;
 891         struct block_device *bdev;
 892         struct list_head *head = &fs_devices->devices;
 893         struct btrfs_device *device;
 894         struct btrfs_device *latest_dev = NULL;
 895         struct buffer_head *bh;
 896         struct btrfs_super_block *disk_super;
 897         u64 devid;
 898         int seeding = 1;
 899         int ret = 0;
 900
 901         flags |= FMODE_EXCL;
 902
 903         list_for_each_entry(device, head, dev_list) {
 904                 if (device->bdev)
 905                         continue;
 906                 if (!device->name)
 907                         continue;
 908
 909                 /* Just open everything we can; ignore failures here */
 910                 if (btrfs_get_bdev_and_sb(device->name->str, flags, holder, 1,
 911                                             &bdev, &bh))
 912                         continue;
 913
 914                 disk_super = (struct btrfs_super_block *)bh->b_data;
 915                 devid = btrfs_stack_device_id(&disk_super->dev_item);
 916                 if (devid != device->devid)
 917                         goto error_brelse;
 918
 919                 if (memcmp(device->uuid, disk_super->dev_item.uuid,
 920                            BTRFS_UUID_SIZE))
 921                         goto error_brelse;
 922
 923                 device->generation = btrfs_super_generation(disk_super);
 924                 if (!latest_dev ||
 925                     device->generation > latest_dev->generation)
 926                         latest_dev = device;
 927
 928                 if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_SEEDING) {
 929                         device->writeable = 0;
 930                 } else {
 931                         device->writeable = !bdev_read_only(bdev);
 932                         seeding = 0;
 933                 }
 934
 935                 q = bdev_get_queue(bdev);
 936                 if (blk_queue_discard(q))
 937                         device->can_discard = 1;
 938
 939                 device->bdev = bdev;
 940                 device->in_fs_metadata = 0;
 941                 device->mode = flags;
 942
 943                 if (!blk_queue_nonrot(bdev_get_queue(bdev)))
 944                         fs_devices->rotating = 1;
 945
 946                 fs_devices->open_devices++;
 947                 if (device->writeable &&
 948                     device->devid != BTRFS_DEV_REPLACE_DEVID) {
 949                         fs_devices->rw_devices++;
 950                         list_add(&device->dev_alloc_list,
 951                                  &fs_devices->alloc_list);
 952                 }
 953                 brelse(bh);
 954                 continue;
 955
 956 error_brelse:
 957                 brelse(bh);
 958                 blkdev_put(bdev, flags);
 959                 continue;
 960         }
 961         if (fs_devices->open_devices == 0) {
 962                 ret = -EINVAL;
 963                 goto out;
 964         }
 965         fs_devices->seeding = seeding;
 966         fs_devices->opened = 1;
 967         fs_devices->latest_bdev = latest_dev->bdev;
 968         fs_devices->total_rw_bytes = 0;
 969 out:
 970         return ret;
 971 }
 972
 973 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 974                        fmode_t flags, void *holder)
 975 {
 976         int ret;
 977
 978         mutex_lock(&uuid_mutex);
 979         if (fs_devices->opened) {
 980                 fs_devices->opened++;
 981                 ret = 0;
 982         } else {
 983                 ret = __btrfs_open_devices(fs_devices, flags, holder);
 984         }
 985         mutex_unlock(&uuid_mutex);
 986         return ret;
 987 }
 988
 989 /*
 990  * Look for a btrfs signature on a device. This may be called out of the mount path
 991  * and we are not allowed to call set_blocksize during the scan. The superblock
 992  * is read via pagecache
 993  */
 994 int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
 995                           struct btrfs_fs_devices **fs_devices_ret)
 996 {
 997         struct btrfs_super_block *disk_super;
 998         struct block_device *bdev;
 999         struct page *page;
1000         void *p;
1001         int ret = -EINVAL;
1002         u64 devid;
1003         u64 transid;
1004         u64 total_devices;
1005         u64 bytenr;
1006         pgoff_t index;
1007
1008         /*
1009          * we would like to check all the supers, but that would make
1010          * a btrfs mount succeed after a mkfs from a different FS.
1011          * So, we need to add a special mount option to scan for
1012          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
1013          */
1014         bytenr = btrfs_sb_offset(0);
1015         flags |= FMODE_EXCL;
1016         mutex_lock(&uuid_mutex);
1017
1018         bdev = blkdev_get_by_path(path, flags, holder);
1019
1020         if (IS_ERR(bdev)) {
1021                 ret = PTR_ERR(bdev);
1022                 goto error;
1023         }
1024
1025         /* make sure our super fits in the device */
1026         if (bytenr + PAGE_CACHE_SIZE >= i_size_read(bdev->bd_inode))
1027                 goto error_bdev_put;
1028
1029         /* make sure our super fits in the page */
1030         if (sizeof(*disk_super) > PAGE_CACHE_SIZE)
1031                 goto error_bdev_put;
1032
1033         /* make sure our super doesn't straddle pages on disk */
1034         index = bytenr >> PAGE_CACHE_SHIFT;
1035         if ((bytenr + sizeof(*disk_super) - 1) >> PAGE_CACHE_SHIFT != index)
1036                 goto error_bdev_put;
1037
1038         /* pull in the page with our super */
1039         page = read_cache_page_gfp(bdev->bd_inode->i_mapping,
1040                                    index, GFP_NOFS);
1041
1042         if (IS_ERR_OR_NULL(page))
1043                 goto error_bdev_put;
1044
1045         p = kmap(page);
1046
1047         /* align our pointer to the offset of the super block */
1048         disk_super = p + (bytenr & ~PAGE_CACHE_MASK);
1049
1050         if (btrfs_super_bytenr(disk_super) != bytenr ||
1051             btrfs_super_magic(disk_super) != BTRFS_MAGIC)
1052                 goto error_unmap;
1053
1054         devid = btrfs_stack_device_id(&disk_super->dev_item);
1055         transid = btrfs_super_generation(disk_super);
1056         total_devices = btrfs_super_num_devices(disk_super);
1057
1058         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
1059         if (ret > 0) {
1060                 if (disk_super->label[0]) {
1061                         if (disk_super->label[BTRFS_LABEL_SIZE - 1])
1062                                 disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
1063                         printk(KERN_INFO "BTRFS: device label %s ", disk_super->label);
1064                 } else {
1065                         printk(KERN_INFO "BTRFS: device fsid %pU ", disk_super->fsid);
1066                 }
1067
1068                 printk(KERN_CONT "devid %llu transid %llu %s\n", devid, transid, path);
1069                 ret = 0;
1070         }
1071         if (!ret && fs_devices_ret)
1072                 (*fs_devices_ret)->total_devices = total_devices;
1073
1074 error_unmap:
1075         kunmap(page);
1076         page_cache_release(page);
1077
1078 error_bdev_put:
1079         blkdev_put(bdev, flags);
1080 error:
1081         mutex_unlock(&uuid_mutex);
1082         return ret;
1083 }
1084
1085 /* helper to account the used device space in the range */
1086 int btrfs_account_dev_extents_size(struct btrfs_device *device, u64 start,
1087                                    u64 end, u64 *length)
1088 {
1089         struct btrfs_key key;
1090         struct btrfs_root *root = device->dev_root;
1091         struct btrfs_dev_extent *dev_extent;
1092         struct btrfs_path *path;
1093         u64 extent_end;
1094         int ret;
1095         int slot;
1096         struct extent_buffer *l;
1097
1098         *length = 0;
1099
1100         if (start >= device->total_bytes || device->is_tgtdev_for_dev_replace)
1101                 return 0;
1102
1103         path = btrfs_alloc_path();
1104         if (!path)
1105                 return -ENOMEM;
1106         path->reada = 2;
1107
1108         key.objectid = device->devid;
1109         key.offset = start;
1110         key.type = BTRFS_DEV_EXTENT_KEY;
1111
1112         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1113         if (ret < 0)
1114                 goto out;
1115         if (ret > 0) {
1116                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1117                 if (ret < 0)
1118                         goto out;
1119         }
1120
1121         while (1) {
1122                 l = path->nodes[0];
1123                 slot = path->slots[0];
1124                 if (slot >= btrfs_header_nritems(l)) {
1125                         ret = btrfs_next_leaf(root, path);
1126                         if (ret == 0)
1127                                 continue;
1128                         if (ret < 0)
1129                                 goto out;
1130
1131                         break;
1132                 }
1133                 btrfs_item_key_to_cpu(l, &key, slot);
1134
1135                 if (key.objectid < device->devid)
1136                         goto next;
1137
1138                 if (key.objectid > device->devid)
1139                         break;
1140
1141                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1142                         goto next;
1143
1144                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1145                 extent_end = key.offset + btrfs_dev_extent_length(l,
1146                                                                   dev_extent);
1147                 if (key.offset <= start && extent_end > end) {
1148                         *length = end - start + 1;
1149                         break;
1150                 } else if (key.offset <= start && extent_end > start)
1151                         *length += extent_end - start;
1152                 else if (key.offset > start && extent_end <= end)
1153                         *length += extent_end - key.offset;
1154                 else if (key.offset > start && key.offset <= end) {
1155                         *length += end - key.offset + 1;
1156                         break;
1157                 } else if (key.offset > end)
1158                         break;
1159
1160 next:
1161                 path->slots[0]++;
1162         }
1163         ret = 0;
1164 out:
1165         btrfs_free_path(path);
1166         return ret;
1167 }
1168
1169 static int contains_pending_extent(struct btrfs_transaction *transaction,
1170                                    struct btrfs_device *device,
1171                                    u64 *start, u64 len)
1172 {
1173         struct btrfs_fs_info *fs_info = device->dev_root->fs_info;
1174         struct extent_map *em;
1175         struct list_head *search_list = &fs_info->pinned_chunks;
1176         int ret = 0;
1177         u64 physical_start = *start;
1178
1179         if (transaction)
1180                 search_list = &transaction->pending_chunks;
1181 again:
1182         list_for_each_entry(em, search_list, list) {
1183                 struct map_lookup *map;
1184                 int i;
1185
1186                 map = (struct map_lookup *)em->bdev;
1187                 for (i = 0; i < map->num_stripes; i++) {
1188                         u64 end;
1189
1190                         if (map->stripes[i].dev != device)
1191                                 continue;
1192                         if (map->stripes[i].physical >= physical_start + len ||
1193                             map->stripes[i].physical + em->orig_block_len <=
1194                             physical_start)
1195                                 continue;
1196                         /*
1197                          * Make sure that while processing the pinned list we do
1198                          * not override our *start with a lower value, because
1199                          * we can have pinned chunks that fall within this
1200                          * device hole and that have lower physical addresses
1201                          * than the pending chunks we processed before. If we
1202                          * do not take this special care we can end up getting
1203                          * 2 pending chunks that start at the same physical
1204                          * device offsets because the end offset of a pinned
1205                          * chunk can be equal to the start offset of some
1206                          * pending chunk.
1207                          */
1208                         end = map->stripes[i].physical + em->orig_block_len;
1209                         if (end > *start) {
1210                                 *start = end;
1211                                 ret = 1;
1212                         }
1213                 }
1214         }
1215         if (search_list != &fs_info->pinned_chunks) {
1216                 search_list = &fs_info->pinned_chunks;
1217                 goto again;
1218         }
1219
1220         return ret;
1221 }
1222
1223
1224 /*
1225  * find_free_dev_extent_start - find free space in the specified device
1226  * @device:       the device which we search the free space in
1227  * @num_bytes:    the size of the free space that we need
1228  * @search_start: the position from which to begin the search
1229  * @start:        store the start of the free space.
1230  * @len:          the size of the free space. that we find, or the size
1231  *                of the max free space if we don't find suitable free space
1232  *
1233  * this uses a pretty simple search, the expectation is that it is
1234  * called very infrequently and that a given device has a small number
1235  * of extents
1236  *
1237  * @start is used to store the start of the free space if we find. But if we
1238  * don't find suitable free space, it will be used to store the start position
1239  * of the max free space.
1240  *
1241  * @len is used to store the size of the free space that we find.
1242  * But if we don't find suitable free space, it is used to store the size of
1243  * the max free space.
1244  */
1245 int find_free_dev_extent_start(struct btrfs_transaction *transaction,
1246                                struct btrfs_device *device, u64 num_bytes,
1247                                u64 search_start, u64 *start, u64 *len)
1248 {
1249         struct btrfs_key key;
1250         struct btrfs_root *root = device->dev_root;
1251         struct btrfs_dev_extent *dev_extent;
1252         struct btrfs_path *path;
1253         u64 hole_size;
1254         u64 max_hole_start;
1255         u64 max_hole_size;
1256         u64 extent_end;
1257         u64 search_end = device->total_bytes;
1258         int ret;
1259         int slot;
1260         struct extent_buffer *l;
1261         u64 min_search_start;
1262
1263         /*
1264          * We don't want to overwrite the superblock on the drive nor any area
1265          * used by the boot loader (grub for example), so we make sure to start
1266          * at an offset of at least 1MB.
1267          */
1268         min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
1269         search_start = max(search_start, min_search_start);
1270
1271         path = btrfs_alloc_path();
1272         if (!path)
1273                 return -ENOMEM;
1274
1275         max_hole_start = search_start;
1276         max_hole_size = 0;
1277
1278 again:
1279         if (search_start >= search_end || device->is_tgtdev_for_dev_replace) {
1280                 ret = -ENOSPC;
1281                 goto out;
1282         }
1283
1284         path->reada = 2;
1285         path->search_commit_root = 1;
1286         path->skip_locking = 1;
1287
1288         key.objectid = device->devid;
1289         key.offset = search_start;
1290         key.type = BTRFS_DEV_EXTENT_KEY;
1291
1292         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1293         if (ret < 0)
1294                 goto out;
1295         if (ret > 0) {
1296                 ret = btrfs_previous_item(root, path, key.objectid, key.type);
1297                 if (ret < 0)
1298                         goto out;
1299         }
1300
1301         while (1) {
1302                 l = path->nodes[0];
1303                 slot = path->slots[0];
1304                 if (slot >= btrfs_header_nritems(l)) {
1305                         ret = btrfs_next_leaf(root, path);
1306                         if (ret == 0)
1307                                 continue;
1308                         if (ret < 0)
1309                                 goto out;
1310
1311                         break;
1312                 }
1313                 btrfs_item_key_to_cpu(l, &key, slot);
1314
1315                 if (key.objectid < device->devid)
1316                         goto next;
1317
1318                 if (key.objectid > device->devid)
1319                         break;
1320
1321                 if (key.type != BTRFS_DEV_EXTENT_KEY)
1322                         goto next;
1323
1324                 if (key.offset > search_start) {
1325                         hole_size = key.offset - search_start;
1326
1327                         /*
1328                          * Have to check before we set max_hole_start, otherwise
1329                          * we could end up sending back this offset anyway.
1330                          */
1331                         if (contains_pending_extent(transaction, device,
1332                                                     &search_start,
1333                                                     hole_size)) {
1334                                 if (key.offset >= search_start) {
1335                                         hole_size = key.offset - search_start;
1336                                 } else {
1337                                         WARN_ON_ONCE(1);
1338                                         hole_size = 0;
1339                                 }
1340                         }
1341
1342                         if (hole_size > max_hole_size) {
1343                                 max_hole_start = search_start;
1344                                 max_hole_size = hole_size;
1345                         }
1346
1347                         /*
1348                          * If this free space is greater than which we need,
1349                          * it must be the max free space that we have found
1350                          * until now, so max_hole_start must point to the start
1351                          * of this free space and the length of this free space
1352                          * is stored in max_hole_size. Thus, we return
1353                          * max_hole_start and max_hole_size and go back to the
1354                          * caller.
1355                          */
1356                         if (hole_size >= num_bytes) {
1357                                 ret = 0;
1358                                 goto out;
1359                         }
1360                 }
1361
1362                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1363                 extent_end = key.offset + btrfs_dev_extent_length(l,
1364                                                                   dev_extent);
1365                 if (extent_end > search_start)
1366                         search_start = extent_end;
1367 next:
1368                 path->slots[0]++;
1369                 cond_resched();
1370         }
1371
1372         /*
1373          * At this point, search_start should be the end of
1374          * allocated dev extents, and when shrinking the device,
1375          * search_end may be smaller than search_start.
1376          */
1377         if (search_end > search_start) {
1378                 hole_size = search_end - search_start;
1379
1380                 if (contains_pending_extent(transaction, device, &search_start,
1381                                             hole_size)) {
1382                         btrfs_release_path(path);
1383                         goto again;
1384                 }
1385
1386                 if (hole_size > max_hole_size) {
1387                         max_hole_start = search_start;
1388                         max_hole_size = hole_size;
1389                 }
1390         }
1391
1392         /* See above. */
1393         if (max_hole_size < num_bytes)
1394                 ret = -ENOSPC;
1395         else
1396                 ret = 0;
1397
1398 out:
1399         btrfs_free_path(path);
1400         *start = max_hole_start;
1401         if (len)
1402                 *len = max_hole_size;
1403         return ret;
1404 }
1405
1406 int find_free_dev_extent(struct btrfs_trans_handle *trans,
1407                          struct btrfs_device *device, u64 num_bytes,
1408                          u64 *start, u64 *len)
1409 {
1410         /* FIXME use last free of some kind */
1411         return find_free_dev_extent_start(trans->transaction, device,
1412                                           num_bytes, 0, start, len);
1413 }
1414
1415 static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
1416                           struct btrfs_device *device,
1417                           u64 start, u64 *dev_extent_len)
1418 {
1419         int ret;
1420         struct btrfs_path *path;
1421         struct btrfs_root *root = device->dev_root;
1422         struct btrfs_key key;
1423         struct btrfs_key found_key;
1424         struct extent_buffer *leaf = NULL;
1425         struct btrfs_dev_extent *extent = NULL;
1426
1427         path = btrfs_alloc_path();
1428         if (!path)
1429                 return -ENOMEM;
1430
1431         key.objectid = device->devid;
1432         key.offset = start;
1433         key.type = BTRFS_DEV_EXTENT_KEY;
1434 again:
1435         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1436         if (ret > 0) {
1437                 ret = btrfs_previous_item(root, path, key.objectid,
1438                                           BTRFS_DEV_EXTENT_KEY);
1439                 if (ret)
1440                         goto out;
1441                 leaf = path->nodes[0];
1442                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1443                 extent = btrfs_item_ptr(leaf, path->slots[0],
1444                                         struct btrfs_dev_extent);
1445                 BUG_ON(found_key.offset > start || found_key.offset +
1446                        btrfs_dev_extent_length(leaf, extent) < start);
1447                 key = found_key;
1448                 btrfs_release_path(path);
1449                 goto again;
1450         } else if (ret == 0) {
1451                 leaf = path->nodes[0];
1452                 extent = btrfs_item_ptr(leaf, path->slots[0],
1453                                         struct btrfs_dev_extent);
1454         } else {
1455                 btrfs_std_error(root->fs_info, ret, "Slot search failed");
1456                 goto out;
1457         }
1458
1459         *dev_extent_len = btrfs_dev_extent_length(leaf, extent);
1460
1461         ret = btrfs_del_item(trans, root, path);
1462         if (ret) {
1463                 btrfs_std_error(root->fs_info, ret,
1464                             "Failed to remove dev extent item");
1465         } else {
1466                 set_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags);
1467         }
1468 out:
1469         btrfs_free_path(path);
1470         return ret;
1471 }
1472
1473 static int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
1474                                   struct btrfs_device *device,
1475                                   u64 chunk_tree, u64 chunk_objectid,
1476                                   u64 chunk_offset, u64 start, u64 num_bytes)
1477 {
1478         int ret;
1479         struct btrfs_path *path;
1480         struct btrfs_root *root = device->dev_root;
1481         struct btrfs_dev_extent *extent;
1482         struct extent_buffer *leaf;
1483         struct btrfs_key key;
1484
1485         WARN_ON(!device->in_fs_metadata);
1486         WARN_ON(device->is_tgtdev_for_dev_replace);
1487         path = btrfs_alloc_path();
1488         if (!path)
1489                 return -ENOMEM;
1490
1491         key.objectid = device->devid;
1492         key.offset = start;
1493         key.type = BTRFS_DEV_EXTENT_KEY;
1494         ret = btrfs_insert_empty_item(trans, root, path, &key,
1495                                       sizeof(*extent));
1496         if (ret)
1497                 goto out;
1498
1499         leaf = path->nodes[0];
1500         extent = btrfs_item_ptr(leaf, path->slots[0],
1501                                 struct btrfs_dev_extent);
1502         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
1503         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
1504         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
1505
1506         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
1507                     btrfs_dev_extent_chunk_tree_uuid(extent), BTRFS_UUID_SIZE);
1508
1509         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
1510         btrfs_mark_buffer_dirty(leaf);
1511 out:
1512         btrfs_free_path(path);
1513         return ret;
1514 }
1515
1516 static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
1517 {
1518         struct extent_map_tree *em_tree;
1519         struct extent_map *em;
1520         struct rb_node *n;
1521         u64 ret = 0;
1522
1523         em_tree = &fs_info->mapping_tree.map_tree;
1524         read_lock(&em_tree->lock);
1525         n = rb_last(&em_tree->map);
1526         if (n) {
1527                 em = rb_entry(n, struct extent_map, rb_node);
1528                 ret = em->start + em->len;
1529         }
1530         read_unlock(&em_tree->lock);
1531
1532         return ret;
1533 }
1534
1535 static noinline int find_next_devid(struct btrfs_fs_info *fs_info,
1536                                     u64 *devid_ret)
1537 {
1538         int ret;
1539         struct btrfs_key key;
1540         struct btrfs_key found_key;
1541         struct btrfs_path *path;
1542
1543         path = btrfs_alloc_path();
1544         if (!path)
1545                 return -ENOMEM;
1546
1547         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1548         key.type = BTRFS_DEV_ITEM_KEY;
1549         key.offset = (u64)-1;
1550
1551         ret = btrfs_search_slot(NULL, fs_info->chunk_root, &key, path, 0, 0);
1552         if (ret < 0)
1553                 goto error;
1554
1555         BUG_ON(ret == 0); /* Corruption */
1556
1557         ret = btrfs_previous_item(fs_info->chunk_root, path,
1558                                   BTRFS_DEV_ITEMS_OBJECTID,
1559                                   BTRFS_DEV_ITEM_KEY);
1560         if (ret) {
1561                 *devid_ret = 1;
1562         } else {
1563                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1564                                       path->slots[0]);
1565                 *devid_ret = found_key.offset + 1;
1566         }
1567         ret = 0;
1568 error:
1569         btrfs_free_path(path);
1570         return ret;
1571 }
1572
1573 /*
1574  * the device information is stored in the chunk root
1575  * the btrfs_device struct should be fully filled in
1576  */
1577 static int btrfs_add_device(struct btrfs_trans_handle *trans,
1578                             struct btrfs_root *root,
1579                             struct btrfs_device *device)
1580 {
1581         int ret;
1582         struct btrfs_path *path;
1583         struct btrfs_dev_item *dev_item;
1584         struct extent_buffer *leaf;
1585         struct btrfs_key key;
1586         unsigned long ptr;
1587
1588         root = root->fs_info->chunk_root;
1589
1590         path = btrfs_alloc_path();
1591         if (!path)
1592                 return -ENOMEM;
1593
1594         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1595         key.type = BTRFS_DEV_ITEM_KEY;
1596         key.offset = device->devid;
1597
1598         ret = btrfs_insert_empty_item(trans, root, path, &key,
1599                                       sizeof(*dev_item));
1600         if (ret)
1601                 goto out;
1602
1603         leaf = path->nodes[0];
1604         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1605
1606         btrfs_set_device_id(leaf, dev_item, device->devid);
1607         btrfs_set_device_generation(leaf, dev_item, 0);
1608         btrfs_set_device_type(leaf, dev_item, device->type);
1609         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1610         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1611         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1612         btrfs_set_device_total_bytes(leaf, dev_item,
1613                                      btrfs_device_get_disk_total_bytes(device));
1614         btrfs_set_device_bytes_used(leaf, dev_item,
1615                                     btrfs_device_get_bytes_used(device));
1616         btrfs_set_device_group(leaf, dev_item, 0);
1617         btrfs_set_device_seek_speed(leaf, dev_item, 0);
1618         btrfs_set_device_bandwidth(leaf, dev_item, 0);
1619         btrfs_set_device_start_offset(leaf, dev_item, 0);
1620
1621         ptr = btrfs_device_uuid(dev_item);
1622         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1623         ptr = btrfs_device_fsid(dev_item);
1624         write_extent_buffer(leaf, root->fs_info->fsid, ptr, BTRFS_UUID_SIZE);
1625         btrfs_mark_buffer_dirty(leaf);
1626
1627         ret = 0;
1628 out:
1629         btrfs_free_path(path);
1630         return ret;
1631 }
1632
1633 /*
1634  * Function to update ctime/mtime for a given device path.
1635  * Mainly used for ctime/mtime based probe like libblkid.
1636  */
1637 static void update_dev_time(char *path_name)
1638 {
1639         struct file *filp;
1640
1641         filp = filp_open(path_name, O_RDWR, 0);
1642         if (IS_ERR(filp))
1643                 return;
1644         file_update_time(filp);
1645         filp_close(filp, NULL);
1646         return;
1647 }
1648
1649 static int btrfs_rm_dev_item(struct btrfs_root *root,
1650                              struct btrfs_device *device)
1651 {
1652         int ret;
1653         struct btrfs_path *path;
1654         struct btrfs_key key;
1655         struct btrfs_trans_handle *trans;
1656
1657         root = root->fs_info->chunk_root;
1658
1659         path = btrfs_alloc_path();
1660         if (!path)
1661                 return -ENOMEM;
1662
1663         trans = btrfs_start_transaction(root, 0);
1664         if (IS_ERR(trans)) {
1665                 btrfs_free_path(path);
1666                 return PTR_ERR(trans);
1667         }
1668         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1669         key.type = BTRFS_DEV_ITEM_KEY;
1670         key.offset = device->devid;
1671
1672         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1673         if (ret < 0)
1674                 goto out;
1675
1676         if (ret > 0) {
1677                 ret = -ENOENT;
1678                 goto out;
1679         }
1680
1681         ret = btrfs_del_item(trans, root, path);
1682         if (ret)
1683                 goto out;
1684 out:
1685         btrfs_free_path(path);
1686         btrfs_commit_transaction(trans, root);
1687         return ret;
1688 }
1689
1690 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
1691 {
1692         struct btrfs_device *device;
1693         struct btrfs_device *next_device;
1694         struct block_device *bdev;
1695         struct buffer_head *bh = NULL;
1696         struct btrfs_super_block *disk_super;
1697         struct btrfs_fs_devices *cur_devices;
1698         u64 all_avail;
1699         u64 devid;
1700         u64 num_devices;
1701         u8 *dev_uuid;
1702         unsigned seq;
1703         int ret = 0;
1704         bool clear_super = false;
1705
1706         mutex_lock(&uuid_mutex);
1707
1708         do {
1709                 seq = read_seqbegin(&root->fs_info->profiles_lock);
1710
1711                 all_avail = root->fs_info->avail_data_alloc_bits |
1712                             root->fs_info->avail_system_alloc_bits |
1713                             root->fs_info->avail_metadata_alloc_bits;
1714         } while (read_seqretry(&root->fs_info->profiles_lock, seq));
1715
1716         num_devices = root->fs_info->fs_devices->num_devices;
1717         btrfs_dev_replace_lock(&root->fs_info->dev_replace);
1718         if (btrfs_dev_replace_is_ongoing(&root->fs_info->dev_replace)) {
1719                 WARN_ON(num_devices < 1);
1720                 num_devices--;
1721         }
1722         btrfs_dev_replace_unlock(&root->fs_info->dev_replace);
1723
1724         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) && num_devices <= 4) {
1725                 ret = BTRFS_ERROR_DEV_RAID10_MIN_NOT_MET;
1726                 goto out;
1727         }
1728
1729         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) && num_devices <= 2) {
1730                 ret = BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET;
1731                 goto out;
1732         }
1733
1734         if ((all_avail & BTRFS_BLOCK_GROUP_RAID5) &&
1735             root->fs_info->fs_devices->rw_devices <= 2) {
1736                 ret = BTRFS_ERROR_DEV_RAID5_MIN_NOT_MET;
1737                 goto out;
1738         }
1739         if ((all_avail & BTRFS_BLOCK_GROUP_RAID6) &&
1740             root->fs_info->fs_devices->rw_devices <= 3) {
1741                 ret = BTRFS_ERROR_DEV_RAID6_MIN_NOT_MET;
1742                 goto out;
1743         }
1744
1745         if (strcmp(device_path, "missing") == 0) {
1746                 struct list_head *devices;
1747                 struct btrfs_device *tmp;
1748
1749                 device = NULL;
1750                 devices = &root->fs_info->fs_devices->devices;
1751                 /*
1752                  * It is safe to read the devices since the volume_mutex
1753                  * is held.
1754                  */
1755                 list_for_each_entry(tmp, devices, dev_list) {
1756                         if (tmp->in_fs_metadata &&
1757                             !tmp->is_tgtdev_for_dev_replace &&
1758                             !tmp->bdev) {
1759                                 device = tmp;
1760                                 break;
1761                         }
1762                 }
1763                 bdev = NULL;
1764                 bh = NULL;
1765                 disk_super = NULL;
1766                 if (!device) {
1767                         ret = BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
1768                         goto out;
1769                 }
1770         } else {
1771                 ret = btrfs_get_bdev_and_sb(device_path,
1772                                             FMODE_WRITE | FMODE_EXCL,
1773                                             root->fs_info->bdev_holder, 0,
1774                                             &bdev, &bh);
1775                 if (ret)
1776                         goto out;
1777                 disk_super = (struct btrfs_super_block *)bh->b_data;
1778                 devid = btrfs_stack_device_id(&disk_super->dev_item);
1779                 dev_uuid = disk_super->dev_item.uuid;
1780                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
1781                                            disk_super->fsid);
1782                 if (!device) {
1783                         ret = -ENOENT;
1784                         goto error_brelse;
1785                 }
1786         }
1787
1788         if (device->is_tgtdev_for_dev_replace) {
1789                 ret = BTRFS_ERROR_DEV_TGT_REPLACE;
1790                 goto error_brelse;
1791         }
1792
1793         if (device->writeable && root->fs_info->fs_devices->rw_devices == 1) {
1794                 ret = BTRFS_ERROR_DEV_ONLY_WRITABLE;
1795                 goto error_brelse;
1796         }
1797
1798         if (device->writeable) {
1799                 lock_chunks(root);
1800                 list_del_init(&device->dev_alloc_list);
1801                 device->fs_devices->rw_devices--;
1802                 unlock_chunks(root);
1803                 clear_super = true;
1804         }
1805
1806         mutex_unlock(&uuid_mutex);
1807         ret = btrfs_shrink_device(device, 0);
1808         mutex_lock(&uuid_mutex);
1809         if (ret)
1810                 goto error_undo;
1811
1812         /*
1813          * TODO: the superblock still includes this device in its num_devices
1814          * counter although write_all_supers() is not locked out. This
1815          * could give a filesystem state which requires a degraded mount.
1816          */
1817         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
1818         if (ret)
1819                 goto error_undo;
1820
1821         device->in_fs_metadata = 0;
1822         btrfs_scrub_cancel_dev(root->fs_info, device);
1823
1824         /*
1825          * the device list mutex makes sure that we don't change
1826          * the device list while someone else is writing out all
1827          * the device supers. Whoever is writing all supers, should
1828          * lock the device list mutex before getting the number of
1829          * devices in the super block (super_copy). Conversely,
1830          * whoever updates the number of devices in the super block
1831          * (super_copy) should hold the device list mutex.
1832          */
1833
1834         cur_devices = device->fs_devices;
1835         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
1836         list_del_rcu(&device->dev_list);
1837
1838         device->fs_devices->num_devices--;
1839         device->fs_devices->total_devices--;
1840
1841         if (device->missing)
1842                 device->fs_devices->missing_devices--;
1843
1844         next_device = list_entry(root->fs_info->fs_devices->devices.next,
1845                                  struct btrfs_device, dev_list);
1846         if (device->bdev == root->fs_info->sb->s_bdev)
1847                 root->fs_info->sb->s_bdev = next_device->bdev;
1848         if (device->bdev == root->fs_info->fs_devices->latest_bdev)
1849                 root->fs_info->fs_devices->latest_bdev = next_device->bdev;
1850
1851         if (device->bdev) {
1852                 device->fs_devices->open_devices--;
1853                 /* remove sysfs entry */
1854                 btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
1855         }
1856
1857         call_rcu(&device->rcu, free_device);
1858
1859         num_devices = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
1860         btrfs_set_super_num_devices(root->fs_info->super_copy, num_devices);
1861         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
1862
1863         if (cur_devices->open_devices == 0) {
1864                 struct btrfs_fs_devices *fs_devices;
1865                 fs_devices = root->fs_info->fs_devices;
1866                 while (fs_devices) {
1867                         if (fs_devices->seed == cur_devices) {
1868                                 fs_devices->seed = cur_devices->seed;
1869                                 break;
1870                         }
1871                         fs_devices = fs_devices->seed;
1872                 }
1873                 cur_devices->seed = NULL;
1874                 __btrfs_close_devices(cur_devices);
1875                 free_fs_devices(cur_devices);
1876         }
1877
1878         root->fs_info->num_tolerated_disk_barrier_failures =
1879                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
1880
1881         /*
1882          * at this point, the device is zero sized.  We want to
1883          * remove it from the devices list and zero out the old super
1884          */
1885         if (clear_super && disk_super) {
1886                 u64 bytenr;
1887                 int i;
1888
1889                 /* make sure this device isn't detected as part of
1890                  * the FS anymore
1891                  */
1892                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
1893                 set_buffer_dirty(bh);
1894                 sync_dirty_buffer(bh);
1895
1896                 /* clear the mirror copies of super block on the disk
1897                  * being removed, 0th copy is been taken care above and
1898                  * the below would take of the rest
1899                  */
1900                 for (i = 1; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1901                         bytenr = btrfs_sb_offset(i);
1902                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
1903                                         i_size_read(bdev->bd_inode))
1904                                 break;
1905
1906                         brelse(bh);
1907                         bh = __bread(bdev, bytenr / 4096,
1908                                         BTRFS_SUPER_INFO_SIZE);
1909                         if (!bh)
1910                                 continue;
1911
1912                         disk_super = (struct btrfs_super_block *)bh->b_data;
1913
1914                         if (btrfs_super_bytenr(disk_super) != bytenr ||
1915                                 btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
1916                                 continue;
1917                         }
1918                         memset(&disk_super->magic, 0,
1919                                                 sizeof(disk_super->magic));
1920                         set_buffer_dirty(bh);
1921                         sync_dirty_buffer(bh);
1922                 }
1923         }
1924
1925         ret = 0;
1926
1927         if (bdev) {
1928                 /* Notify udev that device has changed */
1929                 btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
1930
1931                 /* Update ctime/mtime for device path for libblkid */
1932                 update_dev_time(device_path);
1933         }
1934
1935 error_brelse:
1936         brelse(bh);
1937         if (bdev)
1938                 blkdev_put(bdev, FMODE_READ | FMODE_EXCL);
1939 out:
1940         mutex_unlock(&uuid_mutex);
1941         return ret;
1942 error_undo:
1943         if (device->writeable) {
1944                 lock_chunks(root);
1945                 list_add(&device->dev_alloc_list,
1946                          &root->fs_info->fs_devices->alloc_list);
1947                 device->fs_devices->rw_devices++;
1948                 unlock_chunks(root);
1949         }
1950         goto error_brelse;
1951 }
1952
1953 void btrfs_rm_dev_replace_remove_srcdev(struct btrfs_fs_info *fs_info,
1954                                         struct btrfs_device *srcdev)
1955 {
1956         struct btrfs_fs_devices *fs_devices;
1957
1958         WARN_ON(!mutex_is_locked(&fs_info->fs_devices->device_list_mutex));
1959
1960         /*
1961          * in case of fs with no seed, srcdev->fs_devices will point
1962          * to fs_devices of fs_info. However when the dev being replaced is
1963          * a seed dev it will point to the seed's local fs_devices. In short
1964          * srcdev will have its correct fs_devices in both the cases.
1965          */
1966         fs_devices = srcdev->fs_devices;
1967
1968         list_del_rcu(&srcdev->dev_list);
1969         list_del_rcu(&srcdev->dev_alloc_list);
1970         fs_devices->num_devices--;
1971         if (srcdev->missing)
1972                 fs_devices->missing_devices--;
1973
1974         if (srcdev->writeable) {
1975                 fs_devices->rw_devices--;
1976                 /* zero out the old super if it is writable */
1977                 btrfs_scratch_superblocks(srcdev->bdev, srcdev->name->str);
1978         }
1979
1980         if (srcdev->bdev)
1981                 fs_devices->open_devices--;
1982 }
1983
1984 void btrfs_rm_dev_replace_free_srcdev(struct btrfs_fs_info *fs_info,
1985                                       struct btrfs_device *srcdev)
1986 {
1987         struct btrfs_fs_devices *fs_devices = srcdev->fs_devices;
1988
1989         call_rcu(&srcdev->rcu, free_device);
1990
1991         /*
1992          * unless fs_devices is seed fs, num_devices shouldn't go
1993          * zero
1994          */
1995         BUG_ON(!fs_devices->num_devices && !fs_devices->seeding);
1996
1997         /* if this is no devs we rather delete the fs_devices */
1998         if (!fs_devices->num_devices) {
1999                 struct btrfs_fs_devices *tmp_fs_devices;
2000
2001                 tmp_fs_devices = fs_info->fs_devices;
2002                 while (tmp_fs_devices) {
2003                         if (tmp_fs_devices->seed == fs_devices) {
2004                                 tmp_fs_devices->seed = fs_devices->seed;
2005                                 break;
2006                         }
2007                         tmp_fs_devices = tmp_fs_devices->seed;
2008                 }
2009                 fs_devices->seed = NULL;
2010                 __btrfs_close_devices(fs_devices);
2011                 free_fs_devices(fs_devices);
2012         }
2013 }
2014
2015 void btrfs_destroy_dev_replace_tgtdev(struct btrfs_fs_info *fs_info,
2016                                       struct btrfs_device *tgtdev)
2017 {
2018         struct btrfs_device *next_device;
2019
2020         mutex_lock(&uuid_mutex);
2021         WARN_ON(!tgtdev);
2022         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2023
2024         btrfs_sysfs_rm_device_link(fs_info->fs_devices, tgtdev);
2025
2026         if (tgtdev->bdev) {
2027                 btrfs_scratch_superblocks(tgtdev->bdev, tgtdev->name->str);
2028                 fs_info->fs_devices->open_devices--;
2029         }
2030         fs_info->fs_devices->num_devices--;
2031
2032         next_device = list_entry(fs_info->fs_devices->devices.next,
2033                                  struct btrfs_device, dev_list);
2034         if (tgtdev->bdev == fs_info->sb->s_bdev)
2035                 fs_info->sb->s_bdev = next_device->bdev;
2036         if (tgtdev->bdev == fs_info->fs_devices->latest_bdev)
2037                 fs_info->fs_devices->latest_bdev = next_device->bdev;
2038         list_del_rcu(&tgtdev->dev_list);
2039
2040         call_rcu(&tgtdev->rcu, free_device);
2041
2042         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2043         mutex_unlock(&uuid_mutex);
2044 }
2045
2046 static int btrfs_find_device_by_path(struct btrfs_root *root, char *device_path,
2047                                      struct btrfs_device **device)
2048 {
2049         int ret = 0;
2050         struct btrfs_super_block *disk_super;
2051         u64 devid;
2052         u8 *dev_uuid;
2053         struct block_device *bdev;
2054         struct buffer_head *bh;
2055
2056         *device = NULL;
2057         ret = btrfs_get_bdev_and_sb(device_path, FMODE_READ,
2058                                     root->fs_info->bdev_holder, 0, &bdev, &bh);
2059         if (ret)
2060                 return ret;
2061         disk_super = (struct btrfs_super_block *)bh->b_data;
2062         devid = btrfs_stack_device_id(&disk_super->dev_item);
2063         dev_uuid = disk_super->dev_item.uuid;
2064         *device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2065                                     disk_super->fsid);
2066         brelse(bh);
2067         if (!*device)
2068                 ret = -ENOENT;
2069         blkdev_put(bdev, FMODE_READ);
2070         return ret;
2071 }
2072
2073 int btrfs_find_device_missing_or_by_path(struct btrfs_root *root,
2074                                          char *device_path,
2075                                          struct btrfs_device **device)
2076 {
2077         *device = NULL;
2078         if (strcmp(device_path, "missing") == 0) {
2079                 struct list_head *devices;
2080                 struct btrfs_device *tmp;
2081
2082                 devices = &root->fs_info->fs_devices->devices;
2083                 /*
2084                  * It is safe to read the devices since the volume_mutex
2085                  * is held by the caller.
2086                  */
2087                 list_for_each_entry(tmp, devices, dev_list) {
2088                         if (tmp->in_fs_metadata && !tmp->bdev) {
2089                                 *device = tmp;
2090                                 break;
2091                         }
2092                 }
2093
2094                 if (!*device)
2095                         return BTRFS_ERROR_DEV_MISSING_NOT_FOUND;
2096
2097                 return 0;
2098         } else {
2099                 return btrfs_find_device_by_path(root, device_path, device);
2100         }
2101 }
2102
2103 /*
2104  * does all the dirty work required for changing file system's UUID.
2105  */
2106 static int btrfs_prepare_sprout(struct btrfs_root *root)
2107 {
2108         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2109         struct btrfs_fs_devices *old_devices;
2110         struct btrfs_fs_devices *seed_devices;
2111         struct btrfs_super_block *disk_super = root->fs_info->super_copy;
2112         struct btrfs_device *device;
2113         u64 super_flags;
2114
2115         BUG_ON(!mutex_is_locked(&uuid_mutex));
2116         if (!fs_devices->seeding)
2117                 return -EINVAL;
2118
2119         seed_devices = __alloc_fs_devices();
2120         if (IS_ERR(seed_devices))
2121                 return PTR_ERR(seed_devices);
2122
2123         old_devices = clone_fs_devices(fs_devices);
2124         if (IS_ERR(old_devices)) {
2125                 kfree(seed_devices);
2126                 return PTR_ERR(old_devices);
2127         }
2128
2129         list_add(&old_devices->list, &fs_uuids);
2130
2131         memcpy(seed_devices, fs_devices, sizeof(*seed_devices));
2132         seed_devices->opened = 1;
2133         INIT_LIST_HEAD(&seed_devices->devices);
2134         INIT_LIST_HEAD(&seed_devices->alloc_list);
2135         mutex_init(&seed_devices->device_list_mutex);
2136
2137         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2138         list_splice_init_rcu(&fs_devices->devices, &seed_devices->devices,
2139                               synchronize_rcu);
2140         list_for_each_entry(device, &seed_devices->devices, dev_list)
2141                 device->fs_devices = seed_devices;
2142
2143         lock_chunks(root);
2144         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
2145         unlock_chunks(root);
2146
2147         fs_devices->seeding = 0;
2148         fs_devices->num_devices = 0;
2149         fs_devices->open_devices = 0;
2150         fs_devices->missing_devices = 0;
2151         fs_devices->rotating = 0;
2152         fs_devices->seed = seed_devices;
2153
2154         generate_random_uuid(fs_devices->fsid);
2155         memcpy(root->fs_info->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2156         memcpy(disk_super->fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
2157         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2158
2159         super_flags = btrfs_super_flags(disk_super) &
2160                       ~BTRFS_SUPER_FLAG_SEEDING;
2161         btrfs_set_super_flags(disk_super, super_flags);
2162
2163         return 0;
2164 }
2165
2166 /*
2167  * strore the expected generation for seed devices in device items.
2168  */
2169 static int btrfs_finish_sprout(struct btrfs_trans_handle *trans,
2170                                struct btrfs_root *root)
2171 {
2172         struct btrfs_path *path;
2173         struct extent_buffer *leaf;
2174         struct btrfs_dev_item *dev_item;
2175         struct btrfs_device *device;
2176         struct btrfs_key key;
2177         u8 fs_uuid[BTRFS_UUID_SIZE];
2178         u8 dev_uuid[BTRFS_UUID_SIZE];
2179         u64 devid;
2180         int ret;
2181
2182         path = btrfs_alloc_path();
2183         if (!path)
2184                 return -ENOMEM;
2185
2186         root = root->fs_info->chunk_root;
2187         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2188         key.offset = 0;
2189         key.type = BTRFS_DEV_ITEM_KEY;
2190
2191         while (1) {
2192                 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2193                 if (ret < 0)
2194                         goto error;
2195
2196                 leaf = path->nodes[0];
2197 next_slot:
2198                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
2199                         ret = btrfs_next_leaf(root, path);
2200                         if (ret > 0)
2201                                 break;
2202                         if (ret < 0)
2203                                 goto error;
2204                         leaf = path->nodes[0];
2205                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2206                         btrfs_release_path(path);
2207                         continue;
2208                 }
2209
2210                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2211                 if (key.objectid != BTRFS_DEV_ITEMS_OBJECTID ||
2212                     key.type != BTRFS_DEV_ITEM_KEY)
2213                         break;
2214
2215                 dev_item = btrfs_item_ptr(leaf, path->slots[0],
2216                                           struct btrfs_dev_item);
2217                 devid = btrfs_device_id(leaf, dev_item);
2218                 read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
2219                                    BTRFS_UUID_SIZE);
2220                 read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
2221                                    BTRFS_UUID_SIZE);
2222                 device = btrfs_find_device(root->fs_info, devid, dev_uuid,
2223                                            fs_uuid);
2224                 BUG_ON(!device); /* Logic error */
2225
2226                 if (device->fs_devices->seeding) {
2227                         btrfs_set_device_generation(leaf, dev_item,
2228                                                     device->generation);
2229                         btrfs_mark_buffer_dirty(leaf);
2230                 }
2231
2232                 path->slots[0]++;
2233                 goto next_slot;
2234         }
2235         ret = 0;
2236 error:
2237         btrfs_free_path(path);
2238         return ret;
2239 }
2240
2241 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
2242 {
2243         struct request_queue *q;
2244         struct btrfs_trans_handle *trans;
2245         struct btrfs_device *device;
2246         struct block_device *bdev;
2247         struct list_head *devices;
2248         struct super_block *sb = root->fs_info->sb;
2249         struct rcu_string *name;
2250         u64 tmp;
2251         int seeding_dev = 0;
2252         int ret = 0;
2253
2254         if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
2255                 return -EROFS;
2256
2257         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2258                                   root->fs_info->bdev_holder);
2259         if (IS_ERR(bdev))
2260                 return PTR_ERR(bdev);
2261
2262         if (root->fs_info->fs_devices->seeding) {
2263                 seeding_dev = 1;
2264                 down_write(&sb->s_umount);
2265                 mutex_lock(&uuid_mutex);
2266         }
2267
2268         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2269
2270         devices = &root->fs_info->fs_devices->devices;
2271
2272         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2273         list_for_each_entry(device, devices, dev_list) {
2274                 if (device->bdev == bdev) {
2275                         ret = -EEXIST;
2276                         mutex_unlock(
2277                                 &root->fs_info->fs_devices->device_list_mutex);
2278                         goto error;
2279                 }
2280         }
2281         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2282
2283         device = btrfs_alloc_device(root->fs_info, NULL, NULL);
2284         if (IS_ERR(device)) {
2285                 /* we can safely leave the fs_devices entry around */
2286                 ret = PTR_ERR(device);
2287                 goto error;
2288         }
2289
2290         name = rcu_string_strdup(device_path, GFP_NOFS);
2291         if (!name) {
2292                 kfree(device);
2293                 ret = -ENOMEM;
2294                 goto error;
2295         }
2296         rcu_assign_pointer(device->name, name);
2297
2298         trans = btrfs_start_transaction(root, 0);
2299         if (IS_ERR(trans)) {
2300                 rcu_string_free(device->name);
2301                 kfree(device);
2302                 ret = PTR_ERR(trans);
2303                 goto error;
2304         }
2305
2306         q = bdev_get_queue(bdev);
2307         if (blk_queue_discard(q))
2308                 device->can_discard = 1;
2309         device->writeable = 1;
2310         device->generation = trans->transid;
2311         device->io_width = root->sectorsize;
2312         device->io_align = root->sectorsize;
2313         device->sector_size = root->sectorsize;
2314         device->total_bytes = i_size_read(bdev->bd_inode);
2315         device->disk_total_bytes = device->total_bytes;
2316         device->commit_total_bytes = device->total_bytes;
2317         device->dev_root = root->fs_info->dev_root;
2318         device->bdev = bdev;
2319         device->in_fs_metadata = 1;
2320         device->is_tgtdev_for_dev_replace = 0;
2321         device->mode = FMODE_EXCL;
2322         device->dev_stats_valid = 1;
2323         set_blocksize(device->bdev, 4096);
2324
2325         if (seeding_dev) {
2326                 sb->s_flags &= ~MS_RDONLY;
2327                 ret = btrfs_prepare_sprout(root);
2328                 BUG_ON(ret); /* -ENOMEM */
2329         }
2330
2331         device->fs_devices = root->fs_info->fs_devices;
2332
2333         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2334         lock_chunks(root);
2335         list_add_rcu(&device->dev_list, &root->fs_info->fs_devices->devices);
2336         list_add(&device->dev_alloc_list,
2337                  &root->fs_info->fs_devices->alloc_list);
2338         root->fs_info->fs_devices->num_devices++;
2339         root->fs_info->fs_devices->open_devices++;
2340         root->fs_info->fs_devices->rw_devices++;
2341         root->fs_info->fs_devices->total_devices++;
2342         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
2343
2344         spin_lock(&root->fs_info->free_chunk_lock);
2345         root->fs_info->free_chunk_space += device->total_bytes;
2346         spin_unlock(&root->fs_info->free_chunk_lock);
2347
2348         if (!blk_queue_nonrot(bdev_get_queue(bdev)))
2349                 root->fs_info->fs_devices->rotating = 1;
2350
2351         tmp = btrfs_super_total_bytes(root->fs_info->super_copy);
2352         btrfs_set_super_total_bytes(root->fs_info->super_copy,
2353                                     tmp + device->total_bytes);
2354
2355         tmp = btrfs_super_num_devices(root->fs_info->super_copy);
2356         btrfs_set_super_num_devices(root->fs_info->super_copy,
2357                                     tmp + 1);
2358
2359         /* add sysfs device entry */
2360         btrfs_sysfs_add_device_link(root->fs_info->fs_devices, device);
2361
2362         /*
2363          * we've got more storage, clear any full flags on the space
2364          * infos
2365          */
2366         btrfs_clear_space_info_full(root->fs_info);
2367
2368         unlock_chunks(root);
2369         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2370
2371         if (seeding_dev) {
2372                 lock_chunks(root);
2373                 ret = init_first_rw_device(trans, root, device);
2374                 unlock_chunks(root);
2375                 if (ret) {
2376                         btrfs_abort_transaction(trans, root, ret);
2377                         goto error_trans;
2378                 }
2379         }
2380
2381         ret = btrfs_add_device(trans, root, device);
2382         if (ret) {
2383                 btrfs_abort_transaction(trans, root, ret);
2384                 goto error_trans;
2385         }
2386
2387         if (seeding_dev) {
2388                 char fsid_buf[BTRFS_UUID_UNPARSED_SIZE];
2389
2390                 ret = btrfs_finish_sprout(trans, root);
2391                 if (ret) {
2392                         btrfs_abort_transaction(trans, root, ret);
2393                         goto error_trans;
2394                 }
2395
2396                 /* Sprouting would change fsid of the mounted root,
2397                  * so rename the fsid on the sysfs
2398                  */
2399                 snprintf(fsid_buf, BTRFS_UUID_UNPARSED_SIZE, "%pU",
2400                                                 root->fs_info->fsid);
2401                 if (kobject_rename(&root->fs_info->fs_devices->fsid_kobj,
2402                                                                 fsid_buf))
2403                         btrfs_warn(root->fs_info,
2404                                 "sysfs: failed to create fsid for sprout");
2405         }
2406
2407         root->fs_info->num_tolerated_disk_barrier_failures =
2408                 btrfs_calc_num_tolerated_disk_barrier_failures(root->fs_info);
2409         ret = btrfs_commit_transaction(trans, root);
2410
2411         if (seeding_dev) {
2412                 mutex_unlock(&uuid_mutex);
2413                 up_write(&sb->s_umount);
2414
2415                 if (ret) /* transaction commit */
2416                         return ret;
2417
2418                 ret = btrfs_relocate_sys_chunks(root);
2419                 if (ret < 0)
2420                         btrfs_std_error(root->fs_info, ret,
2421                                     "Failed to relocate sys chunks after "
2422                                     "device initialization. This can be fixed "
2423                                     "using the \"btrfs balance\" command.");
2424                 trans = btrfs_attach_transaction(root);
2425                 if (IS_ERR(trans)) {
2426                         if (PTR_ERR(trans) == -ENOENT)
2427                                 return 0;
2428                         return PTR_ERR(trans);
2429                 }
2430                 ret = btrfs_commit_transaction(trans, root);
2431         }
2432
2433         /* Update ctime/mtime for libblkid */
2434         update_dev_time(device_path);
2435         return ret;
2436
2437 error_trans:
2438         btrfs_end_transaction(trans, root);
2439         rcu_string_free(device->name);
2440         btrfs_sysfs_rm_device_link(root->fs_info->fs_devices, device);
2441         kfree(device);
2442 error:
2443         blkdev_put(bdev, FMODE_EXCL);
2444         if (seeding_dev) {
2445                 mutex_unlock(&uuid_mutex);
2446                 up_write(&sb->s_umount);
2447         }
2448         return ret;
2449 }
2450
2451 int btrfs_init_dev_replace_tgtdev(struct btrfs_root *root, char *device_path,
2452                                   struct btrfs_device *srcdev,
2453                                   struct btrfs_device **device_out)
2454 {
2455         struct request_queue *q;
2456         struct btrfs_device *device;
2457         struct block_device *bdev;
2458         struct btrfs_fs_info *fs_info = root->fs_info;
2459         struct list_head *devices;
2460         struct rcu_string *name;
2461         u64 devid = BTRFS_DEV_REPLACE_DEVID;
2462         int ret = 0;
2463
2464         *device_out = NULL;
2465         if (fs_info->fs_devices->seeding) {
2466                 btrfs_err(fs_info, "the filesystem is a seed filesystem!");
2467                 return -EINVAL;
2468         }
2469
2470         bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL,
2471                                   fs_info->bdev_holder);
2472         if (IS_ERR(bdev)) {
2473                 btrfs_err(fs_info, "target device %s is invalid!", device_path);
2474                 return PTR_ERR(bdev);
2475         }
2476
2477         filemap_write_and_wait(bdev->bd_inode->i_mapping);
2478
2479         devices = &fs_info->fs_devices->devices;
2480         list_for_each_entry(device, devices, dev_list) {
2481                 if (device->bdev == bdev) {
2482                         btrfs_err(fs_info, "target device is in the filesystem!");
2483                         ret = -EEXIST;
2484                         goto error;
2485                 }
2486         }
2487
2488
2489         if (i_size_read(bdev->bd_inode) <
2490             btrfs_device_get_total_bytes(srcdev)) {
2491                 btrfs_err(fs_info, "target device is smaller than source device!");
2492                 ret = -EINVAL;
2493                 goto error;
2494         }
2495
2496
2497         device = btrfs_alloc_device(NULL, &devid, NULL);
2498         if (IS_ERR(device)) {
2499                 ret = PTR_ERR(device);
2500                 goto error;
2501         }
2502
2503         name = rcu_string_strdup(device_path, GFP_NOFS);
2504         if (!name) {
2505                 kfree(device);
2506                 ret = -ENOMEM;
2507                 goto error;
2508         }
2509         rcu_assign_pointer(device->name, name);
2510
2511         q = bdev_get_queue(bdev);
2512         if (blk_queue_discard(q))
2513                 device->can_discard = 1;
2514         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2515         device->writeable = 1;
2516         device->generation = 0;
2517         device->io_width = root->sectorsize;
2518         device->io_align = root->sectorsize;
2519         device->sector_size = root->sectorsize;
2520         device->total_bytes = btrfs_device_get_total_bytes(srcdev);
2521         device->disk_total_bytes = btrfs_device_get_disk_total_bytes(srcdev);
2522         device->bytes_used = btrfs_device_get_bytes_used(srcdev);
2523         ASSERT(list_empty(&srcdev->resized_list));
2524         device->commit_total_bytes = srcdev->commit_total_bytes;
2525         device->commit_bytes_used = device->bytes_used;
2526         device->dev_root = fs_info->dev_root;
2527         device->bdev = bdev;
2528         device->in_fs_metadata = 1;
2529         device->is_tgtdev_for_dev_replace = 1;
2530         device->mode = FMODE_EXCL;
2531         device->dev_stats_valid = 1;
2532         set_blocksize(device->bdev, 4096);
2533         device->fs_devices = fs_info->fs_devices;
2534         list_add(&device->dev_list, &fs_info->fs_devices->devices);
2535         fs_info->fs_devices->num_devices++;
2536         fs_info->fs_devices->open_devices++;
2537         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2538
2539         *device_out = device;
2540         return ret;
2541
2542 error:
2543         blkdev_put(bdev, FMODE_EXCL);
2544         return ret;
2545 }
2546
2547 void btrfs_init_dev_replace_tgtdev_for_resume(struct btrfs_fs_info *fs_info,
2548                                               struct btrfs_device *tgtdev)
2549 {
2550         WARN_ON(fs_info->fs_devices->rw_devices == 0);
2551         tgtdev->io_width = fs_info->dev_root->sectorsize;
2552         tgtdev->io_align = fs_info->dev_root->sectorsize;
2553         tgtdev->sector_size = fs_info->dev_root->sectorsize;
2554         tgtdev->dev_root = fs_info->dev_root;
2555         tgtdev->in_fs_metadata = 1;
2556 }
2557
2558 static noinline int btrfs_update_device(struct btrfs_trans_handle *trans,
2559                                         struct btrfs_device *device)
2560 {
2561         int ret;
2562         struct btrfs_path *path;
2563         struct btrfs_root *root;
2564         struct btrfs_dev_item *dev_item;
2565         struct extent_buffer *leaf;
2566         struct btrfs_key key;
2567
2568         root = device->dev_root->fs_info->chunk_root;
2569
2570         path = btrfs_alloc_path();
2571         if (!path)
2572                 return -ENOMEM;
2573
2574         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2575         key.type = BTRFS_DEV_ITEM_KEY;
2576         key.offset = device->devid;
2577
2578         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
2579         if (ret < 0)
2580                 goto out;
2581
2582         if (ret > 0) {
2583                 ret = -ENOENT;
2584                 goto out;
2585         }
2586
2587         leaf = path->nodes[0];
2588         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
2589
2590         btrfs_set_device_id(leaf, dev_item, device->devid);
2591         btrfs_set_device_type(leaf, dev_item, device->type);
2592         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
2593         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
2594         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
2595         btrfs_set_device_total_bytes(leaf, dev_item,
2596                                      btrfs_device_get_disk_total_bytes(device));
2597         btrfs_set_device_bytes_used(leaf, dev_item,
2598                                     btrfs_device_get_bytes_used(device));
2599         btrfs_mark_buffer_dirty(leaf);
2600
2601 out:
2602         btrfs_free_path(path);
2603         return ret;
2604 }
2605
2606 int btrfs_grow_device(struct btrfs_trans_handle *trans,
2607                       struct btrfs_device *device, u64 new_size)
2608 {
2609         struct btrfs_super_block *super_copy =
2610                 device->dev_root->fs_info->super_copy;
2611         struct btrfs_fs_devices *fs_devices;
2612         u64 old_total;
2613         u64 diff;
2614
2615         if (!device->writeable)
2616                 return -EACCES;
2617
2618         lock_chunks(device->dev_root);
2619         old_total = btrfs_super_total_bytes(super_copy);
2620         diff = new_size - device->total_bytes;
2621
2622         if (new_size <= device->total_bytes ||
2623             device->is_tgtdev_for_dev_replace) {
2624                 unlock_chunks(device->dev_root);
2625                 return -EINVAL;
2626         }
2627
2628         fs_devices = device->dev_root->fs_info->fs_devices;
2629
2630         btrfs_set_super_total_bytes(super_copy, old_total + diff);
2631         device->fs_devices->total_rw_bytes += diff;
2632
2633         btrfs_device_set_total_bytes(device, new_size);
2634         btrfs_device_set_disk_total_bytes(device, new_size);
2635         btrfs_clear_space_info_full(device->dev_root->fs_info);
2636         if (list_empty(&device->resized_list))
2637                 list_add_tail(&device->resized_list,
2638                               &fs_devices->resized_devices);
2639         unlock_chunks(device->dev_root);
2640
2641         return btrfs_update_device(trans, device);
2642 }
2643
2644 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
2645                             struct btrfs_root *root, u64 chunk_objectid,
2646                             u64 chunk_offset)
2647 {
2648         int ret;
2649         struct btrfs_path *path;
2650         struct btrfs_key key;
2651
2652         root = root->fs_info->chunk_root;
2653         path = btrfs_alloc_path();
2654         if (!path)
2655                 return -ENOMEM;
2656
2657         key.objectid = chunk_objectid;
2658         key.offset = chunk_offset;
2659         key.type = BTRFS_CHUNK_ITEM_KEY;
2660
2661         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2662         if (ret < 0)
2663                 goto out;
2664         else if (ret > 0) { /* Logic error or corruption */
2665                 btrfs_std_error(root->fs_info, -ENOENT,
2666                             "Failed lookup while freeing chunk.");
2667                 ret = -ENOENT;
2668                 goto out;
2669         }
2670
2671         ret = btrfs_del_item(trans, root, path);
2672         if (ret < 0)
2673                 btrfs_std_error(root->fs_info, ret,
2674                             "Failed to delete chunk item.");
2675 out:
2676         btrfs_free_path(path);
2677         return ret;
2678 }
2679
2680 static int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
2681                         chunk_offset)
2682 {
2683         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
2684         struct btrfs_disk_key *disk_key;
2685         struct btrfs_chunk *chunk;
2686         u8 *ptr;
2687         int ret = 0;
2688         u32 num_stripes;
2689         u32 array_size;
2690         u32 len = 0;
2691         u32 cur;
2692         struct btrfs_key key;
2693
2694         lock_chunks(root);
2695         array_size = btrfs_super_sys_array_size(super_copy);
2696
2697         ptr = super_copy->sys_chunk_array;
2698         cur = 0;
2699
2700         while (cur < array_size) {
2701                 disk_key = (struct btrfs_disk_key *)ptr;
2702                 btrfs_disk_key_to_cpu(&key, disk_key);
2703
2704                 len = sizeof(*disk_key);
2705
2706                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2707                         chunk = (struct btrfs_chunk *)(ptr + len);
2708                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
2709                         len += btrfs_chunk_item_size(num_stripes);
2710                 } else {
2711                         ret = -EIO;
2712                         break;
2713                 }
2714                 if (key.objectid == chunk_objectid &&
2715                     key.offset == chunk_offset) {
2716                         memmove(ptr, ptr + len, array_size - (cur + len));
2717                         array_size -= len;
2718                         btrfs_set_super_sys_array_size(super_copy, array_size);
2719                 } else {
2720                         ptr += len;
2721                         cur += len;
2722                 }
2723         }
2724         unlock_chunks(root);
2725         return ret;
2726 }
2727
2728 int btrfs_remove_chunk(struct btrfs_trans_handle *trans,
2729                        struct btrfs_root *root, u64 chunk_offset)
2730 {
2731         struct extent_map_tree *em_tree;
2732         struct extent_map *em;
2733         struct btrfs_root *extent_root = root->fs_info->extent_root;
2734         struct map_lookup *map;
2735         u64 dev_extent_len = 0;
2736         u64 chunk_objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2737         int i, ret = 0;
2738
2739         /* Just in case */
2740         root = root->fs_info->chunk_root;
2741         em_tree = &root->fs_info->mapping_tree.map_tree;
2742
2743         read_lock(&em_tree->lock);
2744         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
2745         read_unlock(&em_tree->lock);
2746
2747         if (!em || em->start > chunk_offset ||
2748             em->start + em->len < chunk_offset) {
2749                 /*
2750                  * This is a logic error, but we don't want to just rely on the
2751                  * user having built with ASSERT enabled, so if ASSERT doens't
2752                  * do anything we still error out.
2753                  */
2754                 ASSERT(0);
2755                 if (em)
2756                         free_extent_map(em);
2757                 return -EINVAL;
2758         }
2759         map = (struct map_lookup *)em->bdev;
2760         lock_chunks(root->fs_info->chunk_root);
2761         check_system_chunk(trans, extent_root, map->type);
2762         unlock_chunks(root->fs_info->chunk_root);
2763
2764         for (i = 0; i < map->num_stripes; i++) {
2765                 struct btrfs_device *device = map->stripes[i].dev;
2766                 ret = btrfs_free_dev_extent(trans, device,
2767                                             map->stripes[i].physical,
2768                                             &dev_extent_len);
2769                 if (ret) {
2770                         btrfs_abort_transaction(trans, root, ret);
2771                         goto out;
2772                 }
2773
2774                 if (device->bytes_used > 0) {
2775                         lock_chunks(root);
2776                         btrfs_device_set_bytes_used(device,
2777                                         device->bytes_used - dev_extent_len);
2778                         spin_lock(&root->fs_info->free_chunk_lock);
2779                         root->fs_info->free_chunk_space += dev_extent_len;
2780                         spin_unlock(&root->fs_info->free_chunk_lock);
2781                         btrfs_clear_space_info_full(root->fs_info);
2782                         unlock_chunks(root);
2783                 }
2784
2785                 if (map->stripes[i].dev) {
2786                         ret = btrfs_update_device(trans, map->stripes[i].dev);
2787                         if (ret) {
2788                                 btrfs_abort_transaction(trans, root, ret);
2789                                 goto out;
2790                         }
2791                 }
2792         }
2793         ret = btrfs_free_chunk(trans, root, chunk_objectid, chunk_offset);
2794         if (ret) {
2795                 btrfs_abort_transaction(trans, root, ret);
2796                 goto out;
2797         }
2798
2799         trace_btrfs_chunk_free(root, map, chunk_offset, em->len);
2800
2801         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
2802                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
2803                 if (ret) {
2804                         btrfs_abort_transaction(trans, root, ret);
2805                         goto out;
2806                 }
2807         }
2808
2809         ret = btrfs_remove_block_group(trans, extent_root, chunk_offset, em);
2810         if (ret) {
2811                 btrfs_abort_transaction(trans, extent_root, ret);
2812                 goto out;
2813         }
2814
2815 out:
2816         /* once for us */
2817         free_extent_map(em);
2818         return ret;
2819 }
2820
2821 static int btrfs_relocate_chunk(struct btrfs_root *root, u64 chunk_offset)
2822 {
2823         struct btrfs_root *extent_root;
2824         struct btrfs_trans_handle *trans;
2825         int ret;
2826
2827         root = root->fs_info->chunk_root;
2828         extent_root = root->fs_info->extent_root;
2829
2830         /*
2831          * Prevent races with automatic removal of unused block groups.
2832          * After we relocate and before we remove the chunk with offset
2833          * chunk_offset, automatic removal of the block group can kick in,
2834          * resulting in a failure when calling btrfs_remove_chunk() below.
2835          *
2836          * Make sure to acquire this mutex before doing a tree search (dev
2837          * or chunk trees) to find chunks. Otherwise the cleaner kthread might
2838          * call btrfs_remove_chunk() (through btrfs_delete_unused_bgs()) after
2839          * we release the path used to search the chunk/dev tree and before
2840          * the current task acquires this mutex and calls us.
2841          */
2842         ASSERT(mutex_is_locked(&root->fs_info->delete_unused_bgs_mutex));
2843
2844         ret = btrfs_can_relocate(extent_root, chunk_offset);
2845         if (ret)
2846                 return -ENOSPC;
2847
2848         /* step one, relocate all the extents inside this chunk */
2849         btrfs_scrub_pause(root);
2850         ret = btrfs_relocate_block_group(extent_root, chunk_offset);
2851         btrfs_scrub_continue(root);
2852         if (ret)
2853                 return ret;
2854
2855         trans = btrfs_start_trans_remove_block_group(root->fs_info,
2856                                                      chunk_offset);
2857         if (IS_ERR(trans)) {
2858                 ret = PTR_ERR(trans);
2859                 btrfs_std_error(root->fs_info, ret, NULL);
2860                 return ret;
2861         }
2862
2863         /*
2864          * step two, delete the device extents and the
2865          * chunk tree entries
2866          */
2867         ret = btrfs_remove_chunk(trans, root, chunk_offset);
2868         btrfs_end_transaction(trans, root);
2869         return ret;
2870 }
2871
2872 static int btrfs_relocate_sys_chunks(struct btrfs_root *root)
2873 {
2874         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
2875         struct btrfs_path *path;
2876         struct extent_buffer *leaf;
2877         struct btrfs_chunk *chunk;
2878         struct btrfs_key key;
2879         struct btrfs_key found_key;
2880         u64 chunk_type;
2881         bool retried = false;
2882         int failed = 0;
2883         int ret;
2884
2885         path = btrfs_alloc_path();
2886         if (!path)
2887                 return -ENOMEM;
2888
2889 again:
2890         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
2891         key.offset = (u64)-1;
2892         key.type = BTRFS_CHUNK_ITEM_KEY;
2893
2894         while (1) {
2895                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
2896                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
2897                 if (ret < 0) {
2898                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2899                         goto error;
2900                 }
2901                 BUG_ON(ret == 0); /* Corruption */
2902
2903                 ret = btrfs_previous_item(chunk_root, path, key.objectid,
2904                                           key.type);
2905                 if (ret)
2906                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2907                 if (ret < 0)
2908                         goto error;
2909                 if (ret > 0)
2910                         break;
2911
2912                 leaf = path->nodes[0];
2913                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2914
2915                 chunk = btrfs_item_ptr(leaf, path->slots[0],
2916                                        struct btrfs_chunk);
2917                 chunk_type = btrfs_chunk_type(leaf, chunk);
2918                 btrfs_release_path(path);
2919
2920                 if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) {
2921                         ret = btrfs_relocate_chunk(chunk_root,
2922                                                    found_key.offset);
2923                         if (ret == -ENOSPC)
2924                                 failed++;
2925                         else
2926                                 BUG_ON(ret);
2927                 }
2928                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
2929
2930                 if (found_key.offset == 0)
2931                         break;
2932                 key.offset = found_key.offset - 1;
2933         }
2934         ret = 0;
2935         if (failed && !retried) {
2936                 failed = 0;
2937                 retried = true;
2938                 goto again;
2939         } else if (WARN_ON(failed && retried)) {
2940                 ret = -ENOSPC;
2941         }
2942 error:
2943         btrfs_free_path(path);
2944         return ret;
2945 }
2946
2947 static int insert_balance_item(struct btrfs_root *root,
2948                                struct btrfs_balance_control *bctl)
2949 {
2950         struct btrfs_trans_handle *trans;
2951         struct btrfs_balance_item *item;
2952         struct btrfs_disk_balance_args disk_bargs;
2953         struct btrfs_path *path;
2954         struct extent_buffer *leaf;
2955         struct btrfs_key key;
2956         int ret, err;
2957
2958         path = btrfs_alloc_path();
2959         if (!path)
2960                 return -ENOMEM;
2961
2962         trans = btrfs_start_transaction(root, 0);
2963         if (IS_ERR(trans)) {
2964                 btrfs_free_path(path);
2965                 return PTR_ERR(trans);
2966         }
2967
2968         key.objectid = BTRFS_BALANCE_OBJECTID;
2969         key.type = BTRFS_BALANCE_ITEM_KEY;
2970         key.offset = 0;
2971
2972         ret = btrfs_insert_empty_item(trans, root, path, &key,
2973                                       sizeof(*item));
2974         if (ret)
2975                 goto out;
2976
2977         leaf = path->nodes[0];
2978         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
2979
2980         memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
2981
2982         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->data);
2983         btrfs_set_balance_data(leaf, item, &disk_bargs);
2984         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->meta);
2985         btrfs_set_balance_meta(leaf, item, &disk_bargs);
2986         btrfs_cpu_balance_args_to_disk(&disk_bargs, &bctl->sys);
2987         btrfs_set_balance_sys(leaf, item, &disk_bargs);
2988
2989         btrfs_set_balance_flags(leaf, item, bctl->flags);
2990
2991         btrfs_mark_buffer_dirty(leaf);
2992 out:
2993         btrfs_free_path(path);
2994         err = btrfs_commit_transaction(trans, root);
2995         if (err && !ret)
2996                 ret = err;
2997         return ret;
2998 }
2999
3000 static int del_balance_item(struct btrfs_root *root)
3001 {
3002         struct btrfs_trans_handle *trans;
3003         struct btrfs_path *path;
3004         struct btrfs_key key;
3005         int ret, err;
3006
3007         path = btrfs_alloc_path();
3008         if (!path)
3009                 return -ENOMEM;
3010
3011         trans = btrfs_start_transaction(root, 0);
3012         if (IS_ERR(trans)) {
3013                 btrfs_free_path(path);
3014                 return PTR_ERR(trans);
3015         }
3016
3017         key.objectid = BTRFS_BALANCE_OBJECTID;
3018         key.type = BTRFS_BALANCE_ITEM_KEY;
3019         key.offset = 0;
3020
3021         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3022         if (ret < 0)
3023                 goto out;
3024         if (ret > 0) {
3025                 ret = -ENOENT;
3026                 goto out;
3027         }
3028
3029         ret = btrfs_del_item(trans, root, path);
3030 out:
3031         btrfs_free_path(path);
3032         err = btrfs_commit_transaction(trans, root);
3033         if (err && !ret)
3034                 ret = err;
3035         return ret;
3036 }
3037
3038 /*
3039  * This is a heuristic used to reduce the number of chunks balanced on
3040  * resume after balance was interrupted.
3041  */
3042 static void update_balance_args(struct btrfs_balance_control *bctl)
3043 {
3044         /*
3045          * Turn on soft mode for chunk types that were being converted.
3046          */
3047         if (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)
3048                 bctl->data.flags |= BTRFS_BALANCE_ARGS_SOFT;
3049         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)
3050                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_SOFT;
3051         if (bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)
3052                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_SOFT;
3053
3054         /*
3055          * Turn on usage filter if is not already used.  The idea is
3056          * that chunks that we have already balanced should be
3057          * reasonably full.  Don't do it for chunks that are being
3058          * converted - that will keep us from relocating unconverted
3059          * (albeit full) chunks.
3060          */
3061         if (!(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3062             !(bctl->data.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3063             !(bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3064                 bctl->data.flags |= BTRFS_BALANCE_ARGS_USAGE;
3065                 bctl->data.usage = 90;
3066         }
3067         if (!(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3068             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3069             !(bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3070                 bctl->sys.flags |= BTRFS_BALANCE_ARGS_USAGE;
3071                 bctl->sys.usage = 90;
3072         }
3073         if (!(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE) &&
3074             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3075             !(bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT)) {
3076                 bctl->meta.flags |= BTRFS_BALANCE_ARGS_USAGE;
3077                 bctl->meta.usage = 90;
3078         }
3079 }
3080
3081 /*
3082  * Should be called with both balance and volume mutexes held to
3083  * serialize other volume operations (add_dev/rm_dev/resize) with
3084  * restriper.  Same goes for unset_balance_control.
3085  */
3086 static void set_balance_control(struct btrfs_balance_control *bctl)
3087 {
3088         struct btrfs_fs_info *fs_info = bctl->fs_info;
3089
3090         BUG_ON(fs_info->balance_ctl);
3091
3092         spin_lock(&fs_info->balance_lock);
3093         fs_info->balance_ctl = bctl;
3094         spin_unlock(&fs_info->balance_lock);
3095 }
3096
3097 static void unset_balance_control(struct btrfs_fs_info *fs_info)
3098 {
3099         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3100
3101         BUG_ON(!fs_info->balance_ctl);
3102
3103         spin_lock(&fs_info->balance_lock);
3104         fs_info->balance_ctl = NULL;
3105         spin_unlock(&fs_info->balance_lock);
3106
3107         kfree(bctl);
3108 }
3109
3110 /*
3111  * Balance filters.  Return 1 if chunk should be filtered out
3112  * (should not be balanced).
3113  */
3114 static int chunk_profiles_filter(u64 chunk_type,
3115                                  struct btrfs_balance_args *bargs)
3116 {
3117         chunk_type = chunk_to_extended(chunk_type) &
3118                                 BTRFS_EXTENDED_PROFILE_MASK;
3119
3120         if (bargs->profiles & chunk_type)
3121                 return 0;
3122
3123         return 1;
3124 }
3125
3126 static int chunk_usage_range_filter(struct btrfs_fs_info *fs_info, u64 chunk_offset,
3127                               struct btrfs_balance_args *bargs)
3128 {
3129         struct btrfs_block_group_cache *cache;
3130         u64 chunk_used;
3131         u64 user_thresh_min;
3132         u64 user_thresh_max;
3133         int ret = 1;
3134
3135         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3136         chunk_used = btrfs_block_group_used(&cache->item);
3137
3138         if (bargs->usage_min == 0)
3139                 user_thresh_min = 0;
3140         else
3141                 user_thresh_min = div_factor_fine(cache->key.offset,
3142                                         bargs->usage_min);
3143
3144         if (bargs->usage_max == 0)
3145                 user_thresh_max = 1;
3146         else if (bargs->usage_max > 100)
3147                 user_thresh_max = cache->key.offset;
3148         else
3149                 user_thresh_max = div_factor_fine(cache->key.offset,
3150                                         bargs->usage_max);
3151
3152         if (user_thresh_min <= chunk_used && chunk_used < user_thresh_max)
3153                 ret = 0;
3154
3155         btrfs_put_block_group(cache);
3156         return ret;
3157 }
3158
3159 static int chunk_usage_filter(struct btrfs_fs_info *fs_info,
3160                 u64 chunk_offset, struct btrfs_balance_args *bargs)
3161 {
3162         struct btrfs_block_group_cache *cache;
3163         u64 chunk_used, user_thresh;
3164         int ret = 1;
3165
3166         cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3167         chunk_used = btrfs_block_group_used(&cache->item);
3168
3169         if (bargs->usage_min == 0)
3170                 user_thresh = 1;
3171         else if (bargs->usage > 100)
3172                 user_thresh = cache->key.offset;
3173         else
3174                 user_thresh = div_factor_fine(cache->key.offset,
3175                                               bargs->usage);
3176
3177         if (chunk_used < user_thresh)
3178                 ret = 0;
3179
3180         btrfs_put_block_group(cache);
3181         return ret;
3182 }
3183
3184 static int chunk_devid_filter(struct extent_buffer *leaf,
3185                               struct btrfs_chunk *chunk,
3186                               struct btrfs_balance_args *bargs)
3187 {
3188         struct btrfs_stripe *stripe;
3189         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3190         int i;
3191
3192         for (i = 0; i < num_stripes; i++) {
3193                 stripe = btrfs_stripe_nr(chunk, i);
3194                 if (btrfs_stripe_devid(leaf, stripe) == bargs->devid)
3195                         return 0;
3196         }
3197
3198         return 1;
3199 }
3200
3201 /* [pstart, pend) */
3202 static int chunk_drange_filter(struct extent_buffer *leaf,
3203                                struct btrfs_chunk *chunk,
3204                                u64 chunk_offset,
3205                                struct btrfs_balance_args *bargs)
3206 {
3207         struct btrfs_stripe *stripe;
3208         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3209         u64 stripe_offset;
3210         u64 stripe_length;
3211         int factor;
3212         int i;
3213
3214         if (!(bargs->flags & BTRFS_BALANCE_ARGS_DEVID))
3215                 return 0;
3216
3217         if (btrfs_chunk_type(leaf, chunk) & (BTRFS_BLOCK_GROUP_DUP |
3218              BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)) {
3219                 factor = num_stripes / 2;
3220         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID5) {
3221                 factor = num_stripes - 1;
3222         } else if (btrfs_chunk_type(leaf, chunk) & BTRFS_BLOCK_GROUP_RAID6) {
3223                 factor = num_stripes - 2;
3224         } else {
3225                 factor = num_stripes;
3226         }
3227
3228         for (i = 0; i < num_stripes; i++) {
3229                 stripe = btrfs_stripe_nr(chunk, i);
3230                 if (btrfs_stripe_devid(leaf, stripe) != bargs->devid)
3231                         continue;
3232
3233                 stripe_offset = btrfs_stripe_offset(leaf, stripe);
3234                 stripe_length = btrfs_chunk_length(leaf, chunk);
3235                 stripe_length = div_u64(stripe_length, factor);
3236
3237                 if (stripe_offset < bargs->pend &&
3238                     stripe_offset + stripe_length > bargs->pstart)
3239                         return 0;
3240         }
3241
3242         return 1;
3243 }
3244
3245 /* [vstart, vend) */
3246 static int chunk_vrange_filter(struct extent_buffer *leaf,
3247                                struct btrfs_chunk *chunk,
3248                                u64 chunk_offset,
3249                                struct btrfs_balance_args *bargs)
3250 {
3251         if (chunk_offset < bargs->vend &&
3252             chunk_offset + btrfs_chunk_length(leaf, chunk) > bargs->vstart)
3253                 /* at least part of the chunk is inside this vrange */
3254                 return 0;
3255
3256         return 1;
3257 }
3258
3259 static int chunk_stripes_range_filter(struct extent_buffer *leaf,
3260                                struct btrfs_chunk *chunk,
3261                                struct btrfs_balance_args *bargs)
3262 {
3263         int num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
3264
3265         if (bargs->stripes_min <= num_stripes
3266                         && num_stripes <= bargs->stripes_max)
3267                 return 0;
3268
3269         return 1;
3270 }
3271
3272 static int chunk_soft_convert_filter(u64 chunk_type,
3273                                      struct btrfs_balance_args *bargs)
3274 {
3275         if (!(bargs->flags & BTRFS_BALANCE_ARGS_CONVERT))
3276                 return 0;
3277
3278         chunk_type = chunk_to_extended(chunk_type) &
3279                                 BTRFS_EXTENDED_PROFILE_MASK;
3280
3281         if (bargs->target == chunk_type)
3282                 return 1;
3283
3284         return 0;
3285 }
3286
3287 static int should_balance_chunk(struct btrfs_root *root,
3288                                 struct extent_buffer *leaf,
3289                                 struct btrfs_chunk *chunk, u64 chunk_offset)
3290 {
3291         struct btrfs_balance_control *bctl = root->fs_info->balance_ctl;
3292         struct btrfs_balance_args *bargs = NULL;
3293         u64 chunk_type = btrfs_chunk_type(leaf, chunk);
3294
3295         /* type filter */
3296         if (!((chunk_type & BTRFS_BLOCK_GROUP_TYPE_MASK) &
3297               (bctl->flags & BTRFS_BALANCE_TYPE_MASK))) {
3298                 return 0;
3299         }
3300
3301         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3302                 bargs = &bctl->data;
3303         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3304                 bargs = &bctl->sys;
3305         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3306                 bargs = &bctl->meta;
3307
3308         /* profiles filter */
3309         if ((bargs->flags & BTRFS_BALANCE_ARGS_PROFILES) &&
3310             chunk_profiles_filter(chunk_type, bargs)) {
3311                 return 0;
3312         }
3313
3314         /* usage filter */
3315         if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE) &&
3316             chunk_usage_filter(bctl->fs_info, chunk_offset, bargs)) {
3317                 return 0;
3318         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_USAGE_RANGE) &&
3319             chunk_usage_range_filter(bctl->fs_info, chunk_offset, bargs)) {
3320                 return 0;
3321         }
3322
3323         /* devid filter */
3324         if ((bargs->flags & BTRFS_BALANCE_ARGS_DEVID) &&
3325             chunk_devid_filter(leaf, chunk, bargs)) {
3326                 return 0;
3327         }
3328
3329         /* drange filter, makes sense only with devid filter */
3330         if ((bargs->flags & BTRFS_BALANCE_ARGS_DRANGE) &&
3331             chunk_drange_filter(leaf, chunk, chunk_offset, bargs)) {
3332                 return 0;
3333         }
3334
3335         /* vrange filter */
3336         if ((bargs->flags & BTRFS_BALANCE_ARGS_VRANGE) &&
3337             chunk_vrange_filter(leaf, chunk, chunk_offset, bargs)) {
3338                 return 0;
3339         }
3340
3341         /* stripes filter */
3342         if ((bargs->flags & BTRFS_BALANCE_ARGS_STRIPES_RANGE) &&
3343             chunk_stripes_range_filter(leaf, chunk, bargs)) {
3344                 return 0;
3345         }
3346
3347         /* soft profile changing mode */
3348         if ((bargs->flags & BTRFS_BALANCE_ARGS_SOFT) &&
3349             chunk_soft_convert_filter(chunk_type, bargs)) {
3350                 return 0;
3351         }
3352
3353         /*
3354          * limited by count, must be the last filter
3355          */
3356         if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT)) {
3357                 if (bargs->limit == 0)
3358                         return 0;
3359                 else
3360                         bargs->limit--;
3361         } else if ((bargs->flags & BTRFS_BALANCE_ARGS_LIMIT_RANGE)) {
3362                 /*
3363                  * Same logic as the 'limit' filter; the minimum cannot be
3364                  * determined here because we do not have the global informatoin
3365                  * about the count of all chunks that satisfy the filters.
3366                  */
3367                 if (bargs->limit_max == 0)
3368                         return 0;
3369                 else
3370                         bargs->limit_max--;
3371         }
3372
3373         return 1;
3374 }
3375
3376 static int __btrfs_balance(struct btrfs_fs_info *fs_info)
3377 {
3378         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
3379         struct btrfs_root *chunk_root = fs_info->chunk_root;
3380         struct btrfs_root *dev_root = fs_info->dev_root;
3381         struct list_head *devices;
3382         struct btrfs_device *device;
3383         u64 old_size;
3384         u64 size_to_free;
3385         u64 chunk_type;
3386         struct btrfs_chunk *chunk;
3387         struct btrfs_path *path;
3388         struct btrfs_key key;
3389         struct btrfs_key found_key;
3390         struct btrfs_trans_handle *trans;
3391         struct extent_buffer *leaf;
3392         int slot;
3393         int ret;
3394         int enospc_errors = 0;
3395         bool counting = true;
3396         /* The single value limit and min/max limits use the same bytes in the */
3397         u64 limit_data = bctl->data.limit;
3398         u64 limit_meta = bctl->meta.limit;
3399         u64 limit_sys = bctl->sys.limit;
3400         u32 count_data = 0;
3401         u32 count_meta = 0;
3402         u32 count_sys = 0;
3403         int chunk_reserved = 0;
3404
3405         /* step one make some room on all the devices */
3406         devices = &fs_info->fs_devices->devices;
3407         list_for_each_entry(device, devices, dev_list) {
3408                 old_size = btrfs_device_get_total_bytes(device);
3409                 size_to_free = div_factor(old_size, 1);
3410                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
3411                 if (!device->writeable ||
3412                     btrfs_device_get_total_bytes(device) -
3413                     btrfs_device_get_bytes_used(device) > size_to_free ||
3414                     device->is_tgtdev_for_dev_replace)
3415                         continue;
3416
3417                 ret = btrfs_shrink_device(device, old_size - size_to_free);
3418                 if (ret == -ENOSPC)
3419                         break;
3420                 BUG_ON(ret);
3421
3422                 trans = btrfs_start_transaction(dev_root, 0);
3423                 BUG_ON(IS_ERR(trans));
3424
3425                 ret = btrfs_grow_device(trans, device, old_size);
3426                 BUG_ON(ret);
3427
3428                 btrfs_end_transaction(trans, dev_root);
3429         }
3430
3431         /* step two, relocate all the chunks */
3432         path = btrfs_alloc_path();
3433         if (!path) {
3434                 ret = -ENOMEM;
3435                 goto error;
3436         }
3437
3438         /* zero out stat counters */
3439         spin_lock(&fs_info->balance_lock);
3440         memset(&bctl->stat, 0, sizeof(bctl->stat));
3441         spin_unlock(&fs_info->balance_lock);
3442 again:
3443         if (!counting) {
3444                 /*
3445                  * The single value limit and min/max limits use the same bytes
3446                  * in the
3447                  */
3448                 bctl->data.limit = limit_data;
3449                 bctl->meta.limit = limit_meta;
3450                 bctl->sys.limit = limit_sys;
3451         }
3452         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
3453         key.offset = (u64)-1;
3454         key.type = BTRFS_CHUNK_ITEM_KEY;
3455
3456         while (1) {
3457                 if ((!counting && atomic_read(&fs_info->balance_pause_req)) ||
3458                     atomic_read(&fs_info->balance_cancel_req)) {
3459                         ret = -ECANCELED;
3460                         goto error;
3461                 }
3462
3463                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
3464                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
3465                 if (ret < 0) {
3466                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3467                         goto error;
3468                 }
3469
3470                 /*
3471                  * this shouldn't happen, it means the last relocate
3472                  * failed
3473                  */
3474                 if (ret == 0)
3475                         BUG(); /* FIXME break ? */
3476
3477                 ret = btrfs_previous_item(chunk_root, path, 0,
3478                                           BTRFS_CHUNK_ITEM_KEY);
3479                 if (ret) {
3480                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3481                         ret = 0;
3482                         break;
3483                 }
3484
3485                 leaf = path->nodes[0];
3486                 slot = path->slots[0];
3487                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
3488
3489                 if (found_key.objectid != key.objectid) {
3490                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3491                         break;
3492                 }
3493
3494                 chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
3495                 chunk_type = btrfs_chunk_type(leaf, chunk);
3496
3497                 if (!counting) {
3498                         spin_lock(&fs_info->balance_lock);
3499                         bctl->stat.considered++;
3500                         spin_unlock(&fs_info->balance_lock);
3501                 }
3502
3503                 ret = should_balance_chunk(chunk_root, leaf, chunk,
3504                                            found_key.offset);
3505
3506                 btrfs_release_path(path);
3507                 if (!ret) {
3508                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3509                         goto loop;
3510                 }
3511
3512                 if (counting) {
3513                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3514                         spin_lock(&fs_info->balance_lock);
3515                         bctl->stat.expected++;
3516                         spin_unlock(&fs_info->balance_lock);
3517
3518                         if (chunk_type & BTRFS_BLOCK_GROUP_DATA)
3519                                 count_data++;
3520                         else if (chunk_type & BTRFS_BLOCK_GROUP_SYSTEM)
3521                                 count_sys++;
3522                         else if (chunk_type & BTRFS_BLOCK_GROUP_METADATA)
3523                                 count_meta++;
3524
3525                         goto loop;
3526                 }
3527
3528                 /*
3529                  * Apply limit_min filter, no need to check if the LIMITS
3530                  * filter is used, limit_min is 0 by default
3531                  */
3532                 if (((chunk_type & BTRFS_BLOCK_GROUP_DATA) &&
3533                                         count_data < bctl->data.limit_min)
3534                                 || ((chunk_type & BTRFS_BLOCK_GROUP_METADATA) &&
3535                                         count_meta < bctl->meta.limit_min)
3536                                 || ((chunk_type & BTRFS_BLOCK_GROUP_SYSTEM) &&
3537                                         count_sys < bctl->sys.limit_min)) {
3538                         mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3539                         goto loop;
3540                 }
3541
3542                 if ((chunk_type & BTRFS_BLOCK_GROUP_DATA) && !chunk_reserved) {
3543                         trans = btrfs_start_transaction(chunk_root, 0);
3544                         if (IS_ERR(trans)) {
3545                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3546                                 ret = PTR_ERR(trans);
3547                                 goto error;
3548                         }
3549
3550                         ret = btrfs_force_chunk_alloc(trans, chunk_root,
3551                                                       BTRFS_BLOCK_GROUP_DATA);
3552                         btrfs_end_transaction(trans, chunk_root);
3553                         if (ret < 0) {
3554                                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3555                                 goto error;
3556                         }
3557                         chunk_reserved = 1;
3558                 }
3559
3560                 ret = btrfs_relocate_chunk(chunk_root,
3561                                            found_key.offset);
3562                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
3563                 if (ret && ret != -ENOSPC)
3564                         goto error;
3565                 if (ret == -ENOSPC) {
3566                         enospc_errors++;
3567                 } else {
3568                         spin_lock(&fs_info->balance_lock);
3569                         bctl->stat.completed++;
3570                         spin_unlock(&fs_info->balance_lock);
3571                 }
3572 loop:
3573                 if (found_key.offset == 0)
3574                         break;
3575                 key.offset = found_key.offset - 1;
3576         }
3577
3578         if (counting) {
3579                 btrfs_release_path(path);
3580                 counting = false;
3581                 goto again;
3582         }
3583 error:
3584         btrfs_free_path(path);
3585         if (enospc_errors) {
3586                 btrfs_info(fs_info, "%d enospc errors during balance",
3587                        enospc_errors);
3588                 if (!ret)
3589                         ret = -ENOSPC;
3590         }
3591
3592         return ret;
3593 }
3594
3595 /**
3596  * alloc_profile_is_valid - see if a given profile is valid and reduced
3597  * @flags: profile to validate
3598  * @extended: if true @flags is treated as an extended profile
3599  */
3600 static int alloc_profile_is_valid(u64 flags, int extended)
3601 {
3602         u64 mask = (extended ? BTRFS_EXTENDED_PROFILE_MASK :
3603                                BTRFS_BLOCK_GROUP_PROFILE_MASK);
3604
3605         flags &= ~BTRFS_BLOCK_GROUP_TYPE_MASK;
3606
3607         /* 1) check that all other bits are zeroed */
3608         if (flags & ~mask)
3609                 return 0;
3610
3611         /* 2) see if profile is reduced */
3612         if (flags == 0)
3613                 return !extended; /* "0" is valid for usual profiles */
3614
3615         /* true if exactly one bit set */
3616         return (flags & (flags - 1)) == 0;
3617 }
3618
3619 static inline int balance_need_close(struct btrfs_fs_info *fs_info)
3620 {
3621         /* cancel requested || normal exit path */
3622         return atomic_read(&fs_info->balance_cancel_req) ||
3623                 (atomic_read(&fs_info->balance_pause_req) == 0 &&
3624                  atomic_read(&fs_info->balance_cancel_req) == 0);
3625 }
3626
3627 static void __cancel_balance(struct btrfs_fs_info *fs_info)
3628 {
3629         int ret;
3630
3631         unset_balance_control(fs_info);
3632         ret = del_balance_item(fs_info->tree_root);
3633         if (ret)
3634                 btrfs_std_error(fs_info, ret, NULL);
3635
3636         atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3637 }
3638
3639 /* Non-zero return value signifies invalidity */
3640 static inline int validate_convert_profile(struct btrfs_balance_args *bctl_arg,
3641                 u64 allowed)
3642 {
3643         return ((bctl_arg->flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3644                 (!alloc_profile_is_valid(bctl_arg->target, 1) ||
3645                  (bctl_arg->target & ~allowed)));
3646 }
3647
3648 /*
3649  * Should be called with both balance and volume mutexes held
3650  */
3651 int btrfs_balance(struct btrfs_balance_control *bctl,
3652                   struct btrfs_ioctl_balance_args *bargs)
3653 {
3654         struct btrfs_fs_info *fs_info = bctl->fs_info;
3655         u64 allowed;
3656         int mixed = 0;
3657         int ret;
3658         u64 num_devices;
3659         unsigned seq;
3660
3661         if (btrfs_fs_closing(fs_info) ||
3662             atomic_read(&fs_info->balance_pause_req) ||
3663             atomic_read(&fs_info->balance_cancel_req)) {
3664                 ret = -EINVAL;
3665                 goto out;
3666         }
3667
3668         allowed = btrfs_super_incompat_flags(fs_info->super_copy);
3669         if (allowed & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
3670                 mixed = 1;
3671
3672         /*
3673          * In case of mixed groups both data and meta should be picked,
3674          * and identical options should be given for both of them.
3675          */
3676         allowed = BTRFS_BALANCE_DATA | BTRFS_BALANCE_METADATA;
3677         if (mixed && (bctl->flags & allowed)) {
3678                 if (!(bctl->flags & BTRFS_BALANCE_DATA) ||
3679                     !(bctl->flags & BTRFS_BALANCE_METADATA) ||
3680                     memcmp(&bctl->data, &bctl->meta, sizeof(bctl->data))) {
3681                         btrfs_err(fs_info, "with mixed groups data and "
3682                                    "metadata balance options must be the same");
3683                         ret = -EINVAL;
3684                         goto out;
3685                 }
3686         }
3687
3688         num_devices = fs_info->fs_devices->num_devices;
3689         btrfs_dev_replace_lock(&fs_info->dev_replace);
3690         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
3691                 BUG_ON(num_devices < 1);
3692                 num_devices--;
3693         }
3694         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3695         allowed = BTRFS_AVAIL_ALLOC_BIT_SINGLE;
3696         if (num_devices == 1)
3697                 allowed |= BTRFS_BLOCK_GROUP_DUP;
3698         else if (num_devices > 1)
3699                 allowed |= (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1);
3700         if (num_devices > 2)
3701                 allowed |= BTRFS_BLOCK_GROUP_RAID5;
3702         if (num_devices > 3)
3703                 allowed |= (BTRFS_BLOCK_GROUP_RAID10 |
3704                             BTRFS_BLOCK_GROUP_RAID6);
3705         if (validate_convert_profile(&bctl->data, allowed)) {
3706                 btrfs_err(fs_info, "unable to start balance with target "
3707                            "data profile %llu",
3708                        bctl->data.target);
3709                 ret = -EINVAL;
3710                 goto out;
3711         }
3712         if (validate_convert_profile(&bctl->meta, allowed)) {
3713                 btrfs_err(fs_info,
3714                            "unable to start balance with target metadata profile %llu",
3715                        bctl->meta.target);
3716                 ret = -EINVAL;
3717                 goto out;
3718         }
3719         if (validate_convert_profile(&bctl->sys, allowed)) {
3720                 btrfs_err(fs_info,
3721                            "unable to start balance with target system profile %llu",
3722                        bctl->sys.target);
3723                 ret = -EINVAL;
3724                 goto out;
3725         }
3726
3727         /* allow dup'ed data chunks only in mixed mode */
3728         if (!mixed && (bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3729             (bctl->data.target & BTRFS_BLOCK_GROUP_DUP)) {
3730                 btrfs_err(fs_info, "dup for data is not allowed");
3731                 ret = -EINVAL;
3732                 goto out;
3733         }
3734
3735         /* allow to reduce meta or sys integrity only if force set */
3736         allowed = BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
3737                         BTRFS_BLOCK_GROUP_RAID10 |
3738                         BTRFS_BLOCK_GROUP_RAID5 |
3739                         BTRFS_BLOCK_GROUP_RAID6;
3740         do {
3741                 seq = read_seqbegin(&fs_info->profiles_lock);
3742
3743                 if (((bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3744                      (fs_info->avail_system_alloc_bits & allowed) &&
3745                      !(bctl->sys.target & allowed)) ||
3746                     ((bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) &&
3747                      (fs_info->avail_metadata_alloc_bits & allowed) &&
3748                      !(bctl->meta.target & allowed))) {
3749                         if (bctl->flags & BTRFS_BALANCE_FORCE) {
3750                                 btrfs_info(fs_info, "force reducing metadata integrity");
3751                         } else {
3752                                 btrfs_err(fs_info, "balance will reduce metadata "
3753                                            "integrity, use force if you want this");
3754                                 ret = -EINVAL;
3755                                 goto out;
3756                         }
3757                 }
3758         } while (read_seqretry(&fs_info->profiles_lock, seq));
3759
3760         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3761                 fs_info->num_tolerated_disk_barrier_failures = min(
3762                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
3763                         btrfs_get_num_tolerated_disk_barrier_failures(
3764                                 bctl->sys.target));
3765         }
3766
3767         ret = insert_balance_item(fs_info->tree_root, bctl);
3768         if (ret && ret != -EEXIST)
3769                 goto out;
3770
3771         if (!(bctl->flags & BTRFS_BALANCE_RESUME)) {
3772                 BUG_ON(ret == -EEXIST);
3773                 set_balance_control(bctl);
3774         } else {
3775                 BUG_ON(ret != -EEXIST);
3776                 spin_lock(&fs_info->balance_lock);
3777                 update_balance_args(bctl);
3778                 spin_unlock(&fs_info->balance_lock);
3779         }
3780
3781         atomic_inc(&fs_info->balance_running);
3782         mutex_unlock(&fs_info->balance_mutex);
3783
3784         ret = __btrfs_balance(fs_info);
3785
3786         mutex_lock(&fs_info->balance_mutex);
3787         atomic_dec(&fs_info->balance_running);
3788
3789         if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
3790                 fs_info->num_tolerated_disk_barrier_failures =
3791                         btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
3792         }
3793
3794         if (bargs) {
3795                 memset(bargs, 0, sizeof(*bargs));
3796                 update_ioctl_balance_args(fs_info, 0, bargs);
3797         }
3798
3799         if ((ret && ret != -ECANCELED && ret != -ENOSPC) ||
3800             balance_need_close(fs_info)) {
3801                 __cancel_balance(fs_info);
3802         }
3803
3804         wake_up(&fs_info->balance_wait_q);
3805
3806         return ret;
3807 out:
3808         if (bctl->flags & BTRFS_BALANCE_RESUME)
3809                 __cancel_balance(fs_info);
3810         else {
3811                 kfree(bctl);
3812                 atomic_set(&fs_info->mutually_exclusive_operation_running, 0);
3813         }
3814         return ret;
3815 }
3816
3817 static int balance_kthread(void *data)
3818 {
3819         struct btrfs_fs_info *fs_info = data;
3820         int ret = 0;
3821
3822         mutex_lock(&fs_info->volume_mutex);
3823         mutex_lock(&fs_info->balance_mutex);
3824
3825         if (fs_info->balance_ctl) {
3826                 btrfs_info(fs_info, "continuing balance");
3827                 ret = btrfs_balance(fs_info->balance_ctl, NULL);
3828         }
3829
3830         mutex_unlock(&fs_info->balance_mutex);
3831         mutex_unlock(&fs_info->volume_mutex);
3832
3833         return ret;
3834 }
3835
3836 int btrfs_resume_balance_async(struct btrfs_fs_info *fs_info)
3837 {
3838         struct task_struct *tsk;
3839
3840         spin_lock(&fs_info->balance_lock);
3841         if (!fs_info->balance_ctl) {
3842                 spin_unlock(&fs_info->balance_lock);
3843                 return 0;
3844         }
3845         spin_unlock(&fs_info->balance_lock);
3846
3847         if (btrfs_test_opt(fs_info->tree_root, SKIP_BALANCE)) {
3848                 btrfs_info(fs_info, "force skipping balance");
3849                 return 0;
3850         }
3851
3852         tsk = kthread_run(balance_kthread, fs_info, "btrfs-balance");
3853         return PTR_ERR_OR_ZERO(tsk);
3854 }
3855
3856 int btrfs_recover_balance(struct btrfs_fs_info *fs_info)
3857 {
3858         struct btrfs_balance_control *bctl;
3859         struct btrfs_balance_item *item;
3860         struct btrfs_disk_balance_args disk_bargs;
3861         struct btrfs_path *path;
3862         struct extent_buffer *leaf;
3863         struct btrfs_key key;
3864         int ret;
3865
3866         path = btrfs_alloc_path();
3867         if (!path)
3868                 return -ENOMEM;
3869
3870         key.objectid = BTRFS_BALANCE_OBJECTID;
3871         key.type = BTRFS_BALANCE_ITEM_KEY;
3872         key.offset = 0;
3873
3874         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
3875         if (ret < 0)
3876                 goto out;
3877         if (ret > 0) { /* ret = -ENOENT; */
3878                 ret = 0;
3879                 goto out;
3880         }
3881
3882         bctl = kzalloc(sizeof(*bctl), GFP_NOFS);
3883         if (!bctl) {
3884                 ret = -ENOMEM;
3885                 goto out;
3886         }
3887
3888         leaf = path->nodes[0];
3889         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_balance_item);
3890
3891         bctl->fs_info = fs_info;
3892         bctl->flags = btrfs_balance_flags(leaf, item);
3893         bctl->flags |= BTRFS_BALANCE_RESUME;
3894
3895         btrfs_balance_data(leaf, item, &disk_bargs);
3896         btrfs_disk_balance_args_to_cpu(&bctl->data, &disk_bargs);
3897         btrfs_balance_meta(leaf, item, &disk_bargs);
3898         btrfs_disk_balance_args_to_cpu(&bctl->meta, &disk_bargs);
3899         btrfs_balance_sys(leaf, item, &disk_bargs);
3900         btrfs_disk_balance_args_to_cpu(&bctl->sys, &disk_bargs);
3901
3902         WARN_ON(atomic_xchg(&fs_info->mutually_exclusive_operation_running, 1));
3903
3904         mutex_lock(&fs_info->volume_mutex);
3905         mutex_lock(&fs_info->balance_mutex);
3906
3907         set_balance_control(bctl);
3908
3909         mutex_unlock(&fs_info->balance_mutex);
3910         mutex_unlock(&fs_info->volume_mutex);
3911 out:
3912         btrfs_free_path(path);
3913         return ret;
3914 }
3915
3916 int btrfs_pause_balance(struct btrfs_fs_info *fs_info)
3917 {
3918         int ret = 0;
3919
3920         mutex_lock(&fs_info->balance_mutex);
3921         if (!fs_info->balance_ctl) {
3922                 mutex_unlock(&fs_info->balance_mutex);
3923                 return -ENOTCONN;
3924         }
3925
3926         if (atomic_read(&fs_info->balance_running)) {
3927                 atomic_inc(&fs_info->balance_pause_req);
3928                 mutex_unlock(&fs_info->balance_mutex);
3929
3930                 wait_event(fs_info->balance_wait_q,
3931                            atomic_read(&fs_info->balance_running) == 0);
3932
3933                 mutex_lock(&fs_info->balance_mutex);
3934                 /* we are good with balance_ctl ripped off from under us */
3935                 BUG_ON(atomic_read(&fs_info->balance_running));
3936                 atomic_dec(&fs_info->balance_pause_req);
3937         } else {
3938                 ret = -ENOTCONN;
3939         }
3940
3941         mutex_unlock(&fs_info->balance_mutex);
3942         return ret;
3943 }
3944
3945 int btrfs_cancel_balance(struct btrfs_fs_info *fs_info)
3946 {
3947         if (fs_info->sb->s_flags & MS_RDONLY)
3948                 return -EROFS;
3949
3950         mutex_lock(&fs_info->balance_mutex);
3951         if (!fs_info->balance_ctl) {
3952                 mutex_unlock(&fs_info->balance_mutex);
3953                 return -ENOTCONN;
3954         }
3955
3956         atomic_inc(&fs_info->balance_cancel_req);
3957         /*
3958          * if we are running just wait and return, balance item is
3959          * deleted in btrfs_balance in this case
3960          */
3961         if (atomic_read(&fs_info->balance_running)) {
3962                 mutex_unlock(&fs_info->balance_mutex);
3963                 wait_event(fs_info->balance_wait_q,
3964                            atomic_read(&fs_info->balance_running) == 0);
3965                 mutex_lock(&fs_info->balance_mutex);
3966         } else {
3967                 /* __cancel_balance needs volume_mutex */
3968                 mutex_unlock(&fs_info->balance_mutex);
3969                 mutex_lock(&fs_info->volume_mutex);
3970                 mutex_lock(&fs_info->balance_mutex);
3971
3972                 if (fs_info->balance_ctl)
3973                         __cancel_balance(fs_info);
3974
3975                 mutex_unlock(&fs_info->volume_mutex);
3976         }
3977
3978         BUG_ON(fs_info->balance_ctl || atomic_read(&fs_info->balance_running));
3979         atomic_dec(&fs_info->balance_cancel_req);
3980         mutex_unlock(&fs_info->balance_mutex);
3981         return 0;
3982 }
3983
3984 static int btrfs_uuid_scan_kthread(void *data)
3985 {
3986         struct btrfs_fs_info *fs_info = data;
3987         struct btrfs_root *root = fs_info->tree_root;
3988         struct btrfs_key key;
3989         struct btrfs_key max_key;
3990         struct btrfs_path *path = NULL;
3991         int ret = 0;
3992         struct extent_buffer *eb;
3993         int slot;
3994         struct btrfs_root_item root_item;
3995         u32 item_size;
3996         struct btrfs_trans_handle *trans = NULL;
3997
3998         path = btrfs_alloc_path();
3999         if (!path) {
4000                 ret = -ENOMEM;
4001                 goto out;
4002         }
4003
4004         key.objectid = 0;
4005         key.type = BTRFS_ROOT_ITEM_KEY;
4006         key.offset = 0;
4007
4008         max_key.objectid = (u64)-1;
4009         max_key.type = BTRFS_ROOT_ITEM_KEY;
4010         max_key.offset = (u64)-1;
4011
4012         while (1) {
4013                 ret = btrfs_search_forward(root, &key, path, 0);
4014                 if (ret) {
4015                         if (ret > 0)
4016                                 ret = 0;
4017                         break;
4018                 }
4019
4020                 if (key.type != BTRFS_ROOT_ITEM_KEY ||
4021                     (key.objectid < BTRFS_FIRST_FREE_OBJECTID &&
4022                      key.objectid != BTRFS_FS_TREE_OBJECTID) ||
4023                     key.objectid > BTRFS_LAST_FREE_OBJECTID)
4024                         goto skip;
4025
4026                 eb = path->nodes[0];
4027                 slot = path->slots[0];
4028                 item_size = btrfs_item_size_nr(eb, slot);
4029                 if (item_size < sizeof(root_item))
4030                         goto skip;
4031
4032                 read_extent_buffer(eb, &root_item,
4033                                    btrfs_item_ptr_offset(eb, slot),
4034                                    (int)sizeof(root_item));
4035                 if (btrfs_root_refs(&root_item) == 0)
4036                         goto skip;
4037
4038                 if (!btrfs_is_empty_uuid(root_item.uuid) ||
4039                     !btrfs_is_empty_uuid(root_item.received_uuid)) {
4040                         if (trans)
4041                                 goto update_tree;
4042
4043                         btrfs_release_path(path);
4044                         /*
4045                          * 1 - subvol uuid item
4046                          * 1 - received_subvol uuid item
4047                          */
4048                         trans = btrfs_start_transaction(fs_info->uuid_root, 2);
4049                         if (IS_ERR(trans)) {
4050                                 ret = PTR_ERR(trans);
4051                                 break;
4052                         }
4053                         continue;
4054                 } else {
4055                         goto skip;
4056                 }
4057 update_tree:
4058                 if (!btrfs_is_empty_uuid(root_item.uuid)) {
4059                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4060                                                   root_item.uuid,
4061                                                   BTRFS_UUID_KEY_SUBVOL,
4062                                                   key.objectid);
4063                         if (ret < 0) {
4064                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4065                                         ret);
4066                                 break;
4067                         }
4068                 }
4069
4070                 if (!btrfs_is_empty_uuid(root_item.received_uuid)) {
4071                         ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
4072                                                   root_item.received_uuid,
4073                                                  BTRFS_UUID_KEY_RECEIVED_SUBVOL,
4074                                                   key.objectid);
4075                         if (ret < 0) {
4076                                 btrfs_warn(fs_info, "uuid_tree_add failed %d",
4077                                         ret);
4078                                 break;
4079                         }
4080                 }
4081
4082 skip:
4083                 if (trans) {
4084                         ret = btrfs_end_transaction(trans, fs_info->uuid_root);
4085                         trans = NULL;
4086                         if (ret)
4087                                 break;
4088                 }
4089
4090                 btrfs_release_path(path);
4091                 if (key.offset < (u64)-1) {
4092                         key.offset++;
4093                 } else if (key.type < BTRFS_ROOT_ITEM_KEY) {
4094                         key.offset = 0;
4095                         key.type = BTRFS_ROOT_ITEM_KEY;
4096                 } else if (key.objectid < (u64)-1) {
4097                         key.offset = 0;
4098                         key.type = BTRFS_ROOT_ITEM_KEY;
4099                         key.objectid++;
4100                 } else {
4101                         break;
4102                 }
4103                 cond_resched();
4104         }
4105
4106 out:
4107         btrfs_free_path(path);
4108         if (trans && !IS_ERR(trans))
4109                 btrfs_end_transaction(trans, fs_info->uuid_root);
4110         if (ret)
4111                 btrfs_warn(fs_info, "btrfs_uuid_scan_kthread failed %d", ret);
4112         else
4113                 fs_info->update_uuid_tree_gen = 1;
4114         up(&fs_info->uuid_tree_rescan_sem);
4115         return 0;
4116 }
4117
4118 /*
4119  * Callback for btrfs_uuid_tree_iterate().
4120  * returns:
4121  * 0    check succeeded, the entry is not outdated.
4122  * < 0  if an error occured.
4123  * > 0  if the check failed, which means the caller shall remove the entry.
4124  */
4125 static int btrfs_check_uuid_tree_entry(struct btrfs_fs_info *fs_info,
4126                                        u8 *uuid, u8 type, u64 subid)
4127 {
4128         struct btrfs_key key;
4129         int ret = 0;
4130         struct btrfs_root *subvol_root;
4131
4132         if (type != BTRFS_UUID_KEY_SUBVOL &&
4133             type != BTRFS_UUID_KEY_RECEIVED_SUBVOL)
4134                 goto out;
4135
4136         key.objectid = subid;
4137         key.type = BTRFS_ROOT_ITEM_KEY;
4138         key.offset = (u64)-1;
4139         subvol_root = btrfs_read_fs_root_no_name(fs_info, &key);
4140         if (IS_ERR(subvol_root)) {
4141                 ret = PTR_ERR(subvol_root);
4142                 if (ret == -ENOENT)
4143                         ret = 1;
4144                 goto out;
4145         }
4146
4147         switch (type) {
4148         case BTRFS_UUID_KEY_SUBVOL:
4149                 if (memcmp(uuid, subvol_root->root_item.uuid, BTRFS_UUID_SIZE))
4150                         ret = 1;
4151                 break;
4152         case BTRFS_UUID_KEY_RECEIVED_SUBVOL:
4153                 if (memcmp(uuid, subvol_root->root_item.received_uuid,
4154                            BTRFS_UUID_SIZE))
4155                         ret = 1;
4156                 break;
4157         }
4158
4159 out:
4160         return ret;
4161 }
4162
4163 static int btrfs_uuid_rescan_kthread(void *data)
4164 {
4165         struct btrfs_fs_info *fs_info = (struct btrfs_fs_info *)data;
4166         int ret;
4167
4168         /*
4169          * 1st step is to iterate through the existing UUID tree and
4170          * to delete all entries that contain outdated data.
4171          * 2nd step is to add all missing entries to the UUID tree.
4172          */
4173         ret = btrfs_uuid_tree_iterate(fs_info, btrfs_check_uuid_tree_entry);
4174         if (ret < 0) {
4175                 btrfs_warn(fs_info, "iterating uuid_tree failed %d", ret);
4176                 up(&fs_info->uuid_tree_rescan_sem);
4177                 return ret;
4178         }
4179         return btrfs_uuid_scan_kthread(data);
4180 }
4181
4182 int btrfs_create_uuid_tree(struct btrfs_fs_info *fs_info)
4183 {
4184         struct btrfs_trans_handle *trans;
4185         struct btrfs_root *tree_root = fs_info->tree_root;
4186         struct btrfs_root *uuid_root;
4187         struct task_struct *task;
4188         int ret;
4189
4190         /*
4191          * 1 - root node
4192          * 1 - root item
4193          */
4194         trans = btrfs_start_transaction(tree_root, 2);
4195         if (IS_ERR(trans))
4196                 return PTR_ERR(trans);
4197
4198         uuid_root = btrfs_create_tree(trans, fs_info,
4199                                       BTRFS_UUID_TREE_OBJECTID);
4200         if (IS_ERR(uuid_root)) {
4201                 ret = PTR_ERR(uuid_root);
4202                 btrfs_abort_transaction(trans, tree_root, ret);
4203                 return ret;
4204         }
4205
4206         fs_info->uuid_root = uuid_root;
4207
4208         ret = btrfs_commit_transaction(trans, tree_root);
4209         if (ret)
4210                 return ret;
4211
4212         down(&fs_info->uuid_tree_rescan_sem);
4213         task = kthread_run(btrfs_uuid_scan_kthread, fs_info, "btrfs-uuid");
4214         if (IS_ERR(task)) {
4215                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4216                 btrfs_warn(fs_info, "failed to start uuid_scan task");
4217                 up(&fs_info->uuid_tree_rescan_sem);
4218                 return PTR_ERR(task);
4219         }
4220
4221         return 0;
4222 }
4223
4224 int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
4225 {
4226         struct task_struct *task;
4227
4228         down(&fs_info->uuid_tree_rescan_sem);
4229         task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
4230         if (IS_ERR(task)) {
4231                 /* fs_info->update_uuid_tree_gen remains 0 in all error case */
4232                 btrfs_warn(fs_info, "failed to start uuid_rescan task");
4233                 up(&fs_info->uuid_tree_rescan_sem);
4234                 return PTR_ERR(task);
4235         }
4236
4237         return 0;
4238 }
4239
4240 /*
4241  * shrinking a device means finding all of the device extents past
4242  * the new size, and then following the back refs to the chunks.
4243  * The chunk relocation code actually frees the device extent
4244  */
4245 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
4246 {
4247         struct btrfs_trans_handle *trans;
4248         struct btrfs_root *root = device->dev_root;
4249         struct btrfs_dev_extent *dev_extent = NULL;
4250         struct btrfs_path *path;
4251         u64 length;
4252         u64 chunk_offset;
4253         int ret;
4254         int slot;
4255         int failed = 0;
4256         bool retried = false;
4257         bool checked_pending_chunks = false;
4258         struct extent_buffer *l;
4259         struct btrfs_key key;
4260         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4261         u64 old_total = btrfs_super_total_bytes(super_copy);
4262         u64 old_size = btrfs_device_get_total_bytes(device);
4263         u64 diff = old_size - new_size;
4264
4265         if (device->is_tgtdev_for_dev_replace)
4266                 return -EINVAL;
4267
4268         path = btrfs_alloc_path();
4269         if (!path)
4270                 return -ENOMEM;
4271
4272         path->reada = 2;
4273
4274         lock_chunks(root);
4275
4276         btrfs_device_set_total_bytes(device, new_size);
4277         if (device->writeable) {
4278                 device->fs_devices->total_rw_bytes -= diff;
4279                 spin_lock(&root->fs_info->free_chunk_lock);
4280                 root->fs_info->free_chunk_space -= diff;
4281                 spin_unlock(&root->fs_info->free_chunk_lock);
4282         }
4283         unlock_chunks(root);
4284
4285 again:
4286         key.objectid = device->devid;
4287         key.offset = (u64)-1;
4288         key.type = BTRFS_DEV_EXTENT_KEY;
4289
4290         do {
4291                 mutex_lock(&root->fs_info->delete_unused_bgs_mutex);
4292                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4293                 if (ret < 0) {
4294                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4295                         goto done;
4296                 }
4297
4298                 ret = btrfs_previous_item(root, path, 0, key.type);
4299                 if (ret)
4300                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4301                 if (ret < 0)
4302                         goto done;
4303                 if (ret) {
4304                         ret = 0;
4305                         btrfs_release_path(path);
4306                         break;
4307                 }
4308
4309                 l = path->nodes[0];
4310                 slot = path->slots[0];
4311                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
4312
4313                 if (key.objectid != device->devid) {
4314                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4315                         btrfs_release_path(path);
4316                         break;
4317                 }
4318
4319                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
4320                 length = btrfs_dev_extent_length(l, dev_extent);
4321
4322                 if (key.offset + length <= new_size) {
4323                         mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4324                         btrfs_release_path(path);
4325                         break;
4326                 }
4327
4328                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
4329                 btrfs_release_path(path);
4330
4331                 ret = btrfs_relocate_chunk(root, chunk_offset);
4332                 mutex_unlock(&root->fs_info->delete_unused_bgs_mutex);
4333                 if (ret && ret != -ENOSPC)
4334                         goto done;
4335                 if (ret == -ENOSPC)
4336                         failed++;
4337         } while (key.offset-- > 0);
4338
4339         if (failed && !retried) {
4340                 failed = 0;
4341                 retried = true;
4342                 goto again;
4343         } else if (failed && retried) {
4344                 ret = -ENOSPC;
4345                 goto done;
4346         }
4347
4348         /* Shrinking succeeded, else we would be at "done". */
4349         trans = btrfs_start_transaction(root, 0);
4350         if (IS_ERR(trans)) {
4351                 ret = PTR_ERR(trans);
4352                 goto done;
4353         }
4354
4355         lock_chunks(root);
4356
4357         /*
4358          * We checked in the above loop all device extents that were already in
4359          * the device tree. However before we have updated the device's
4360          * total_bytes to the new size, we might have had chunk allocations that
4361          * have not complete yet (new block groups attached to transaction
4362          * handles), and therefore their device extents were not yet in the
4363          * device tree and we missed them in the loop above. So if we have any
4364          * pending chunk using a device extent that overlaps the device range
4365          * that we can not use anymore, commit the current transaction and
4366          * repeat the search on the device tree - this way we guarantee we will
4367          * not have chunks using device extents that end beyond 'new_size'.
4368          */
4369         if (!checked_pending_chunks) {
4370                 u64 start = new_size;
4371                 u64 len = old_size - new_size;
4372
4373                 if (contains_pending_extent(trans->transaction, device,
4374                                             &start, len)) {
4375                         unlock_chunks(root);
4376                         checked_pending_chunks = true;
4377                         failed = 0;
4378                         retried = false;
4379                         ret = btrfs_commit_transaction(trans, root);
4380                         if (ret)
4381                                 goto done;
4382                         goto again;
4383                 }
4384         }
4385
4386         btrfs_device_set_disk_total_bytes(device, new_size);
4387         if (list_empty(&device->resized_list))
4388                 list_add_tail(&device->resized_list,
4389                               &root->fs_info->fs_devices->resized_devices);
4390
4391         WARN_ON(diff > old_total);
4392         btrfs_set_super_total_bytes(super_copy, old_total - diff);
4393         unlock_chunks(root);
4394
4395         /* Now btrfs_update_device() will change the on-disk size. */
4396         ret = btrfs_update_device(trans, device);
4397         btrfs_end_transaction(trans, root);
4398 done:
4399         btrfs_free_path(path);
4400         if (ret) {
4401                 lock_chunks(root);
4402                 btrfs_device_set_total_bytes(device, old_size);
4403                 if (device->writeable)
4404                         device->fs_devices->total_rw_bytes += diff;
4405                 spin_lock(&root->fs_info->free_chunk_lock);
4406                 root->fs_info->free_chunk_space += diff;
4407                 spin_unlock(&root->fs_info->free_chunk_lock);
4408                 unlock_chunks(root);
4409         }
4410         return ret;
4411 }
4412
4413 static int btrfs_add_system_chunk(struct btrfs_root *root,
4414                            struct btrfs_key *key,
4415                            struct btrfs_chunk *chunk, int item_size)
4416 {
4417         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
4418         struct btrfs_disk_key disk_key;
4419         u32 array_size;
4420         u8 *ptr;
4421
4422         lock_chunks(root);
4423         array_size = btrfs_super_sys_array_size(super_copy);
4424         if (array_size + item_size + sizeof(disk_key)
4425                         > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4426                 unlock_chunks(root);
4427                 return -EFBIG;
4428         }
4429
4430         ptr = super_copy->sys_chunk_array + array_size;
4431         btrfs_cpu_key_to_disk(&disk_key, key);
4432         memcpy(ptr, &disk_key, sizeof(disk_key));
4433         ptr += sizeof(disk_key);
4434         memcpy(ptr, chunk, item_size);
4435         item_size += sizeof(disk_key);
4436         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
4437         unlock_chunks(root);
4438
4439         return 0;
4440 }
4441
4442 /*
4443  * sort the devices in descending order by max_avail, total_avail
4444  */
4445 static int btrfs_cmp_device_info(const void *a, const void *b)
4446 {
4447         const struct btrfs_device_info *di_a = a;
4448         const struct btrfs_device_info *di_b = b;
4449
4450         if (di_a->max_avail > di_b->max_avail)
4451                 return -1;
4452         if (di_a->max_avail < di_b->max_avail)
4453                 return 1;
4454         if (di_a->total_avail > di_b->total_avail)
4455                 return -1;
4456         if (di_a->total_avail < di_b->total_avail)
4457                 return 1;
4458         return 0;
4459 }
4460
4461 static u32 find_raid56_stripe_len(u32 data_devices, u32 dev_stripe_target)
4462 {
4463         /* TODO allow them to set a preferred stripe size */
4464         return 64 * 1024;
4465 }
4466
4467 static void check_raid56_incompat_flag(struct btrfs_fs_info *info, u64 type)
4468 {
4469         if (!(type & BTRFS_BLOCK_GROUP_RAID56_MASK))
4470                 return;
4471
4472         btrfs_set_fs_incompat(info, RAID56);
4473 }
4474
4475 #define BTRFS_MAX_DEVS(r) ((BTRFS_LEAF_DATA_SIZE(r)             \
4476                         - sizeof(struct btrfs_item)             \
4477                         - sizeof(struct btrfs_chunk))           \
4478                         / sizeof(struct btrfs_stripe) + 1)
4479
4480 #define BTRFS_MAX_DEVS_SYS_CHUNK ((BTRFS_SYSTEM_CHUNK_ARRAY_SIZE        \
4481                                 - 2 * sizeof(struct btrfs_disk_key)     \
4482                                 - 2 * sizeof(struct btrfs_chunk))       \
4483                                 / sizeof(struct btrfs_stripe) + 1)
4484
4485 static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4486                                struct btrfs_root *extent_root, u64 start,
4487                                u64 type)
4488 {
4489         struct btrfs_fs_info *info = extent_root->fs_info;
4490         struct btrfs_fs_devices *fs_devices = info->fs_devices;
4491         struct list_head *cur;
4492         struct map_lookup *map = NULL;
4493         struct extent_map_tree *em_tree;
4494         struct extent_map *em;
4495         struct btrfs_device_info *devices_info = NULL;
4496         u64 total_avail;
4497         int num_stripes;        /* total number of stripes to allocate */
4498         int data_stripes;       /* number of stripes that count for
4499                                    block group size */
4500         int sub_stripes;        /* sub_stripes info for map */
4501         int dev_stripes;        /* stripes per dev */
4502         int devs_max;           /* max devs to use */
4503         int devs_min;           /* min devs needed */
4504         int devs_increment;     /* ndevs has to be a multiple of this */
4505         int ncopies;            /* how many copies to data has */
4506         int ret;
4507         u64 max_stripe_size;
4508         u64 max_chunk_size;
4509         u64 stripe_size;
4510         u64 num_bytes;
4511         u64 raid_stripe_len = BTRFS_STRIPE_LEN;
4512         int ndevs;
4513         int i;
4514         int j;
4515         int index;
4516
4517         BUG_ON(!alloc_profile_is_valid(type, 0));
4518
4519         if (list_empty(&fs_devices->alloc_list))
4520                 return -ENOSPC;
4521
4522         index = __get_raid_index(type);
4523
4524         sub_stripes = btrfs_raid_array[index].sub_stripes;
4525         dev_stripes = btrfs_raid_array[index].dev_stripes;
4526         devs_max = btrfs_raid_array[index].devs_max;
4527         devs_min = btrfs_raid_array[index].devs_min;
4528         devs_increment = btrfs_raid_array[index].devs_increment;
4529         ncopies = btrfs_raid_array[index].ncopies;
4530
4531         if (type & BTRFS_BLOCK_GROUP_DATA) {
4532                 max_stripe_size = 1024 * 1024 * 1024;
4533                 max_chunk_size = 10 * max_stripe_size;
4534                 if (!devs_max)
4535                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4536         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
4537                 /* for larger filesystems, use larger metadata chunks */
4538                 if (fs_devices->total_rw_bytes > 50ULL * 1024 * 1024 * 1024)
4539                         max_stripe_size = 1024 * 1024 * 1024;
4540                 else
4541                         max_stripe_size = 256 * 1024 * 1024;
4542                 max_chunk_size = max_stripe_size;
4543                 if (!devs_max)
4544                         devs_max = BTRFS_MAX_DEVS(info->chunk_root);
4545         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
4546                 max_stripe_size = 32 * 1024 * 1024;
4547                 max_chunk_size = 2 * max_stripe_size;
4548                 if (!devs_max)
4549                         devs_max = BTRFS_MAX_DEVS_SYS_CHUNK;
4550         } else {
4551                 btrfs_err(info, "invalid chunk type 0x%llx requested",
4552                        type);
4553                 BUG_ON(1);
4554         }
4555
4556         /* we don't want a chunk larger than 10% of writeable space */
4557         max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
4558                              max_chunk_size);
4559
4560         devices_info = kcalloc(fs_devices->rw_devices, sizeof(*devices_info),
4561                                GFP_NOFS);
4562         if (!devices_info)
4563                 return -ENOMEM;
4564
4565         cur = fs_devices->alloc_list.next;
4566
4567         /*
4568          * in the first pass through the devices list, we gather information
4569          * about the available holes on each device.
4570          */
4571         ndevs = 0;
4572         while (cur != &fs_devices->alloc_list) {
4573                 struct btrfs_device *device;
4574                 u64 max_avail;
4575                 u64 dev_offset;
4576
4577                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
4578
4579                 cur = cur->next;
4580
4581                 if (!device->writeable) {
4582                         WARN(1, KERN_ERR
4583                                "BTRFS: read-only device in alloc_list\n");
4584                         continue;
4585                 }
4586
4587                 if (!device->in_fs_metadata ||
4588                     device->is_tgtdev_for_dev_replace)
4589                         continue;
4590
4591                 if (device->total_bytes > device->bytes_used)
4592                         total_avail = device->total_bytes - device->bytes_used;
4593                 else
4594                         total_avail = 0;
4595
4596                 /* If there is no space on this device, skip it. */
4597                 if (total_avail == 0)
4598                         continue;
4599
4600                 ret = find_free_dev_extent(trans, device,
4601                                            max_stripe_size * dev_stripes,
4602                                            &dev_offset, &max_avail);
4603                 if (ret && ret != -ENOSPC)
4604                         goto error;
4605
4606                 if (ret == 0)
4607                         max_avail = max_stripe_size * dev_stripes;
4608
4609                 if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
4610                         continue;
4611
4612                 if (ndevs == fs_devices->rw_devices) {
4613                         WARN(1, "%s: found more than %llu devices\n",
4614                              __func__, fs_devices->rw_devices);
4615                         break;
4616                 }
4617                 devices_info[ndevs].dev_offset = dev_offset;
4618                 devices_info[ndevs].max_avail = max_avail;
4619                 devices_info[ndevs].total_avail = total_avail;
4620                 devices_info[ndevs].dev = device;
4621                 ++ndevs;
4622         }
4623
4624         /*
4625          * now sort the devices by hole size / available space
4626          */
4627         sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
4628              btrfs_cmp_device_info, NULL);
4629
4630         /* round down to number of usable stripes */
4631         ndevs -= ndevs % devs_increment;
4632
4633         if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
4634                 ret = -ENOSPC;
4635                 goto error;
4636         }
4637
4638         if (devs_max && ndevs > devs_max)
4639                 ndevs = devs_max;
4640         /*
4641          * the primary goal is to maximize the number of stripes, so use as many
4642          * devices as possible, even if the stripes are not maximum sized.
4643          */
4644         stripe_size = devices_info[ndevs-1].max_avail;
4645         num_stripes = ndevs * dev_stripes;
4646
4647         /*
4648          * this will have to be fixed for RAID1 and RAID10 over
4649          * more drives
4650          */
4651         data_stripes = num_stripes / ncopies;
4652
4653         if (type & BTRFS_BLOCK_GROUP_RAID5) {
4654                 raid_stripe_len = find_raid56_stripe_len(ndevs - 1,
4655                                  btrfs_super_stripesize(info->super_copy));
4656                 data_stripes = num_stripes - 1;
4657         }
4658         if (type & BTRFS_BLOCK_GROUP_RAID6) {
4659                 raid_stripe_len = find_raid56_stripe_len(ndevs - 2,
4660                                  btrfs_super_stripesize(info->super_copy));
4661                 data_stripes = num_stripes - 2;
4662         }
4663
4664         /*
4665          * Use the number of data stripes to figure out how big this chunk
4666          * is really going to be in terms of logical address space,
4667          * and compare that answer with the max chunk size
4668          */
4669         if (stripe_size * data_stripes > max_chunk_size) {
4670                 u64 mask = (1ULL << 24) - 1;
4671
4672                 stripe_size = div_u64(max_chunk_size, data_stripes);
4673
4674                 /* bump the answer up to a 16MB boundary */
4675                 stripe_size = (stripe_size + mask) & ~mask;
4676
4677                 /* but don't go higher than the limits we found
4678                  * while searching for free extents
4679                  */
4680                 if (stripe_size > devices_info[ndevs-1].max_avail)
4681                         stripe_size = devices_info[ndevs-1].max_avail;
4682         }
4683
4684         stripe_size = div_u64(stripe_size, dev_stripes);
4685
4686         /* align to BTRFS_STRIPE_LEN */
4687         stripe_size = div_u64(stripe_size, raid_stripe_len);
4688         stripe_size *= raid_stripe_len;
4689
4690         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
4691         if (!map) {
4692                 ret = -ENOMEM;
4693                 goto error;
4694         }
4695         map->num_stripes = num_stripes;
4696
4697         for (i = 0; i < ndevs; ++i) {
4698                 for (j = 0; j < dev_stripes; ++j) {
4699                         int s = i * dev_stripes + j;
4700                         map->stripes[s].dev = devices_info[i].dev;
4701                         map->stripes[s].physical = devices_info[i].dev_offset +
4702                                                    j * stripe_size;
4703                 }
4704         }
4705         map->sector_size = extent_root->sectorsize;
4706         map->stripe_len = raid_stripe_len;
4707         map->io_align = raid_stripe_len;
4708         map->io_width = raid_stripe_len;
4709         map->type = type;
4710         map->sub_stripes = sub_stripes;
4711
4712         num_bytes = stripe_size * data_stripes;
4713
4714         trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
4715
4716         em = alloc_extent_map();
4717         if (!em) {
4718                 kfree(map);
4719                 ret = -ENOMEM;
4720                 goto error;
4721         }
4722         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
4723         em->bdev = (struct block_device *)map;
4724         em->start = start;
4725         em->len = num_bytes;
4726         em->block_start = 0;
4727         em->block_len = em->len;
4728         em->orig_block_len = stripe_size;
4729
4730         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4731         write_lock(&em_tree->lock);
4732         ret = add_extent_mapping(em_tree, em, 0);
4733         if (!ret) {
4734                 list_add_tail(&em->list, &trans->transaction->pending_chunks);
4735                 atomic_inc(&em->refs);
4736         }
4737         write_unlock(&em_tree->lock);
4738         if (ret) {
4739                 free_extent_map(em);
4740                 goto error;
4741         }
4742
4743         ret = btrfs_make_block_group(trans, extent_root, 0, type,
4744                                      BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4745                                      start, num_bytes);
4746         if (ret)
4747                 goto error_del_extent;
4748
4749         for (i = 0; i < map->num_stripes; i++) {
4750                 num_bytes = map->stripes[i].dev->bytes_used + stripe_size;
4751                 btrfs_device_set_bytes_used(map->stripes[i].dev, num_bytes);
4752         }
4753
4754         spin_lock(&extent_root->fs_info->free_chunk_lock);
4755         extent_root->fs_info->free_chunk_space -= (stripe_size *
4756                                                    map->num_stripes);
4757         spin_unlock(&extent_root->fs_info->free_chunk_lock);
4758
4759         free_extent_map(em);
4760         check_raid56_incompat_flag(extent_root->fs_info, type);
4761
4762         kfree(devices_info);
4763         return 0;
4764
4765 error_del_extent:
4766         write_lock(&em_tree->lock);
4767         remove_extent_mapping(em_tree, em);
4768         write_unlock(&em_tree->lock);
4769
4770         /* One for our allocation */
4771         free_extent_map(em);
4772         /* One for the tree reference */
4773         free_extent_map(em);
4774         /* One for the pending_chunks list reference */
4775         free_extent_map(em);
4776 error:
4777         kfree(devices_info);
4778         return ret;
4779 }
4780
4781 int btrfs_finish_chunk_alloc(struct btrfs_trans_handle *trans,
4782                                 struct btrfs_root *extent_root,
4783                                 u64 chunk_offset, u64 chunk_size)
4784 {
4785         struct btrfs_key key;
4786         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
4787         struct btrfs_device *device;
4788         struct btrfs_chunk *chunk;
4789         struct btrfs_stripe *stripe;
4790         struct extent_map_tree *em_tree;
4791         struct extent_map *em;
4792         struct map_lookup *map;
4793         size_t item_size;
4794         u64 dev_offset;
4795         u64 stripe_size;
4796         int i = 0;
4797         int ret;
4798
4799         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
4800         read_lock(&em_tree->lock);
4801         em = lookup_extent_mapping(em_tree, chunk_offset, chunk_size);
4802         read_unlock(&em_tree->lock);
4803
4804         if (!em) {
4805                 btrfs_crit(extent_root->fs_info, "unable to find logical "
4806                            "%Lu len %Lu", chunk_offset, chunk_size);
4807                 return -EINVAL;
4808         }
4809
4810         if (em->start != chunk_offset || em->len != chunk_size) {
4811                 btrfs_crit(extent_root->fs_info, "found a bad mapping, wanted"
4812                           " %Lu-%Lu, found %Lu-%Lu", chunk_offset,
4813                           chunk_size, em->start, em->len);
4814                 free_extent_map(em);
4815                 return -EINVAL;
4816         }
4817
4818         map = (struct map_lookup *)em->bdev;
4819         item_size = btrfs_chunk_item_size(map->num_stripes);
4820         stripe_size = em->orig_block_len;
4821
4822         chunk = kzalloc(item_size, GFP_NOFS);
4823         if (!chunk) {
4824                 ret = -ENOMEM;
4825                 goto out;
4826         }
4827
4828         for (i = 0; i < map->num_stripes; i++) {
4829                 device = map->stripes[i].dev;
4830                 dev_offset = map->stripes[i].physical;
4831
4832                 ret = btrfs_update_device(trans, device);
4833                 if (ret)
4834                         goto out;
4835                 ret = btrfs_alloc_dev_extent(trans, device,
4836                                              chunk_root->root_key.objectid,
4837                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID,
4838                                              chunk_offset, dev_offset,
4839                                              stripe_size);
4840                 if (ret)
4841                         goto out;
4842         }
4843
4844         stripe = &chunk->stripe;
4845         for (i = 0; i < map->num_stripes; i++) {
4846                 device = map->stripes[i].dev;
4847                 dev_offset = map->stripes[i].physical;
4848
4849                 btrfs_set_stack_stripe_devid(stripe, device->devid);
4850                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
4851                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
4852                 stripe++;
4853         }
4854
4855         btrfs_set_stack_chunk_length(chunk, chunk_size);
4856         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
4857         btrfs_set_stack_chunk_stripe_len(chunk, map->stripe_len);
4858         btrfs_set_stack_chunk_type(chunk, map->type);
4859         btrfs_set_stack_chunk_num_stripes(chunk, map->num_stripes);
4860         btrfs_set_stack_chunk_io_align(chunk, map->stripe_len);
4861         btrfs_set_stack_chunk_io_width(chunk, map->stripe_len);
4862         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
4863         btrfs_set_stack_chunk_sub_stripes(chunk, map->sub_stripes);
4864
4865         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
4866         key.type = BTRFS_CHUNK_ITEM_KEY;
4867         key.offset = chunk_offset;
4868
4869         ret = btrfs_insert_item(trans, chunk_root, &key, chunk, item_size);
4870         if (ret == 0 && map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
4871                 /*
4872                  * TODO: Cleanup of inserted chunk root in case of
4873                  * failure.
4874                  */
4875                 ret = btrfs_add_system_chunk(chunk_root, &key, chunk,
4876                                              item_size);
4877         }
4878
4879 out:
4880         kfree(chunk);
4881         free_extent_map(em);
4882         return ret;
4883 }
4884
4885 /*
4886  * Chunk allocation falls into two parts. The first part does works
4887  * that make the new allocated chunk useable, but not do any operation
4888  * that modifies the chunk tree. The second part does the works that
4889  * require modifying the chunk tree. This division is important for the
4890  * bootstrap process of adding storage to a seed btrfs.
4891  */
4892 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
4893                       struct btrfs_root *extent_root, u64 type)
4894 {
4895         u64 chunk_offset;
4896
4897         ASSERT(mutex_is_locked(&extent_root->fs_info->chunk_mutex));
4898         chunk_offset = find_next_chunk(extent_root->fs_info);
4899         return __btrfs_alloc_chunk(trans, extent_root, chunk_offset, type);
4900 }
4901
4902 static noinline int init_first_rw_device(struct btrfs_trans_handle *trans,
4903                                          struct btrfs_root *root,
4904                                          struct btrfs_device *device)
4905 {
4906         u64 chunk_offset;
4907         u64 sys_chunk_offset;
4908         u64 alloc_profile;
4909         struct btrfs_fs_info *fs_info = root->fs_info;
4910         struct btrfs_root *extent_root = fs_info->extent_root;
4911         int ret;
4912
4913         chunk_offset = find_next_chunk(fs_info);
4914         alloc_profile = btrfs_get_alloc_profile(extent_root, 0);
4915         ret = __btrfs_alloc_chunk(trans, extent_root, chunk_offset,
4916                                   alloc_profile);
4917         if (ret)
4918                 return ret;
4919
4920         sys_chunk_offset = find_next_chunk(root->fs_info);
4921         alloc_profile = btrfs_get_alloc_profile(fs_info->chunk_root, 0);
4922         ret = __btrfs_alloc_chunk(trans, extent_root, sys_chunk_offset,
4923                                   alloc_profile);
4924         return ret;
4925 }
4926
4927 static inline int btrfs_chunk_max_errors(struct map_lookup *map)
4928 {
4929         int max_errors;
4930
4931         if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
4932                          BTRFS_BLOCK_GROUP_RAID10 |
4933                          BTRFS_BLOCK_GROUP_RAID5 |
4934                          BTRFS_BLOCK_GROUP_DUP)) {
4935                 max_errors = 1;
4936         } else if (map->type & BTRFS_BLOCK_GROUP_RAID6) {
4937                 max_errors = 2;
4938         } else {
4939                 max_errors = 0;
4940         }
4941
4942         return max_errors;
4943 }
4944
4945 int btrfs_chunk_readonly(struct btrfs_root *root, u64 chunk_offset)
4946 {
4947         struct extent_map *em;
4948         struct map_lookup *map;
4949         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
4950         int readonly = 0;
4951         int miss_ndevs = 0;
4952         int i;
4953
4954         read_lock(&map_tree->map_tree.lock);
4955         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
4956         read_unlock(&map_tree->map_tree.lock);
4957         if (!em)
4958                 return 1;
4959
4960         map = (struct map_lookup *)em->bdev;
4961         for (i = 0; i < map->num_stripes; i++) {
4962                 if (map->stripes[i].dev->missing) {
4963                         miss_ndevs++;
4964                         continue;
4965                 }
4966
4967                 if (!map->stripes[i].dev->writeable) {
4968                         readonly = 1;
4969                         goto end;
4970                 }
4971         }
4972
4973         /*
4974          * If the number of missing devices is larger than max errors,
4975          * we can not write the data into that chunk successfully, so
4976          * set it readonly.
4977          */
4978         if (miss_ndevs > btrfs_chunk_max_errors(map))
4979                 readonly = 1;
4980 end:
4981         free_extent_map(em);
4982         return readonly;
4983 }
4984
4985 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
4986 {
4987         extent_map_tree_init(&tree->map_tree);
4988 }
4989
4990 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
4991 {
4992         struct extent_map *em;
4993
4994         while (1) {
4995                 write_lock(&tree->map_tree.lock);
4996                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
4997                 if (em)
4998                         remove_extent_mapping(&tree->map_tree, em);
4999                 write_unlock(&tree->map_tree.lock);
5000                 if (!em)
5001                         break;
5002                 /* once for us */
5003                 free_extent_map(em);
5004                 /* once for the tree */
5005                 free_extent_map(em);
5006         }
5007 }
5008
5009 int btrfs_num_copies(struct btrfs_fs_info *fs_info, u64 logical, u64 len)
5010 {
5011         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5012         struct extent_map *em;
5013         struct map_lookup *map;
5014         struct extent_map_tree *em_tree = &map_tree->map_tree;
5015         int ret;
5016
5017         read_lock(&em_tree->lock);
5018         em = lookup_extent_mapping(em_tree, logical, len);
5019         read_unlock(&em_tree->lock);
5020
5021         /*
5022          * We could return errors for these cases, but that could get ugly and
5023          * we'd probably do the same thing which is just not do anything else
5024          * and exit, so return 1 so the callers don't try to use other copies.
5025          */
5026         if (!em) {
5027                 btrfs_crit(fs_info, "No mapping for %Lu-%Lu", logical,
5028                             logical+len);
5029                 return 1;
5030         }
5031
5032         if (em->start > logical || em->start + em->len < logical) {
5033                 btrfs_crit(fs_info, "Invalid mapping for %Lu-%Lu, got "
5034                             "%Lu-%Lu", logical, logical+len, em->start,
5035                             em->start + em->len);
5036                 free_extent_map(em);
5037                 return 1;
5038         }
5039
5040         map = (struct map_lookup *)em->bdev;
5041         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
5042                 ret = map->num_stripes;
5043         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5044                 ret = map->sub_stripes;
5045         else if (map->type & BTRFS_BLOCK_GROUP_RAID5)
5046                 ret = 2;
5047         else if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5048                 ret = 3;
5049         else
5050                 ret = 1;
5051         free_extent_map(em);
5052
5053         btrfs_dev_replace_lock(&fs_info->dev_replace);
5054         if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))
5055                 ret++;
5056         btrfs_dev_replace_unlock(&fs_info->dev_replace);
5057
5058         return ret;
5059 }
5060
5061 unsigned long btrfs_full_stripe_len(struct btrfs_root *root,
5062                                     struct btrfs_mapping_tree *map_tree,
5063                                     u64 logical)
5064 {
5065         struct extent_map *em;
5066         struct map_lookup *map;
5067         struct extent_map_tree *em_tree = &map_tree->map_tree;
5068         unsigned long len = root->sectorsize;
5069
5070         read_lock(&em_tree->lock);
5071         em = lookup_extent_mapping(em_tree, logical, len);
5072         read_unlock(&em_tree->lock);
5073         BUG_ON(!em);
5074
5075         BUG_ON(em->start > logical || em->start + em->len < logical);
5076         map = (struct map_lookup *)em->bdev;
5077         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5078                 len = map->stripe_len * nr_data_stripes(map);
5079         free_extent_map(em);
5080         return len;
5081 }
5082
5083 int btrfs_is_parity_mirror(struct btrfs_mapping_tree *map_tree,
5084                            u64 logical, u64 len, int mirror_num)
5085 {
5086         struct extent_map *em;
5087         struct map_lookup *map;
5088         struct extent_map_tree *em_tree = &map_tree->map_tree;
5089         int ret = 0;
5090
5091         read_lock(&em_tree->lock);
5092         em = lookup_extent_mapping(em_tree, logical, len);
5093         read_unlock(&em_tree->lock);
5094         BUG_ON(!em);
5095
5096         BUG_ON(em->start > logical || em->start + em->len < logical);
5097         map = (struct map_lookup *)em->bdev;
5098         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
5099                 ret = 1;
5100         free_extent_map(em);
5101         return ret;
5102 }
5103
5104 static int find_live_mirror(struct btrfs_fs_info *fs_info,
5105                             struct map_lookup *map, int first, int num,
5106                             int optimal, int dev_replace_is_ongoing)
5107 {
5108         int i;
5109         int tolerance;
5110         struct btrfs_device *srcdev;
5111
5112         if (dev_replace_is_ongoing &&
5113             fs_info->dev_replace.cont_reading_from_srcdev_mode ==
5114              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID)
5115                 srcdev = fs_info->dev_replace.srcdev;
5116         else
5117                 srcdev = NULL;
5118
5119         /*
5120          * try to avoid the drive that is the source drive for a
5121          * dev-replace procedure, only choose it if no other non-missing
5122          * mirror is available
5123          */
5124         for (tolerance = 0; tolerance < 2; tolerance++) {
5125                 if (map->stripes[optimal].dev->bdev &&
5126                     (tolerance || map->stripes[optimal].dev != srcdev))
5127                         return optimal;
5128                 for (i = first; i < first + num; i++) {
5129                         if (map->stripes[i].dev->bdev &&
5130                             (tolerance || map->stripes[i].dev != srcdev))
5131                                 return i;
5132                 }
5133         }
5134
5135         /* we couldn't find one that doesn't fail.  Just return something
5136          * and the io error handling code will clean up eventually
5137          */
5138         return optimal;
5139 }
5140
5141 static inline int parity_smaller(u64 a, u64 b)
5142 {
5143         return a > b;
5144 }
5145
5146 /* Bubble-sort the stripe set to put the parity/syndrome stripes last */
5147 static void sort_parity_stripes(struct btrfs_bio *bbio, int num_stripes)
5148 {
5149         struct btrfs_bio_stripe s;
5150         int i;
5151         u64 l;
5152         int again = 1;
5153
5154         while (again) {
5155                 again = 0;
5156                 for (i = 0; i < num_stripes - 1; i++) {
5157                         if (parity_smaller(bbio->raid_map[i],
5158                                            bbio->raid_map[i+1])) {
5159                                 s = bbio->stripes[i];
5160                                 l = bbio->raid_map[i];
5161                                 bbio->stripes[i] = bbio->stripes[i+1];
5162                                 bbio->raid_map[i] = bbio->raid_map[i+1];
5163                                 bbio->stripes[i+1] = s;
5164                                 bbio->raid_map[i+1] = l;
5165
5166                                 again = 1;
5167                         }
5168                 }
5169         }
5170 }
5171
5172 static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
5173 {
5174         struct btrfs_bio *bbio = kzalloc(
5175                  /* the size of the btrfs_bio */
5176                 sizeof(struct btrfs_bio) +
5177                 /* plus the variable array for the stripes */
5178                 sizeof(struct btrfs_bio_stripe) * (total_stripes) +
5179                 /* plus the variable array for the tgt dev */
5180                 sizeof(int) * (real_stripes) +
5181                 /*
5182                  * plus the raid_map, which includes both the tgt dev
5183                  * and the stripes
5184                  */
5185                 sizeof(u64) * (total_stripes),
5186                 GFP_NOFS|__GFP_NOFAIL);
5187
5188         atomic_set(&bbio->error, 0);
5189         atomic_set(&bbio->refs, 1);
5190
5191         return bbio;
5192 }
5193
5194 void btrfs_get_bbio(struct btrfs_bio *bbio)
5195 {
5196         WARN_ON(!atomic_read(&bbio->refs));
5197         atomic_inc(&bbio->refs);
5198 }
5199
5200 void btrfs_put_bbio(struct btrfs_bio *bbio)
5201 {
5202         if (!bbio)
5203                 return;
5204         if (atomic_dec_and_test(&bbio->refs))
5205                 kfree(bbio);
5206 }
5207
5208 static int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5209                              u64 logical, u64 *length,
5210                              struct btrfs_bio **bbio_ret,
5211                              int mirror_num, int need_raid_map)
5212 {
5213         struct extent_map *em;
5214         struct map_lookup *map;
5215         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
5216         struct extent_map_tree *em_tree = &map_tree->map_tree;
5217         u64 offset;
5218         u64 stripe_offset;
5219         u64 stripe_end_offset;
5220         u64 stripe_nr;
5221         u64 stripe_nr_orig;
5222         u64 stripe_nr_end;
5223         u64 stripe_len;
5224         u32 stripe_index;
5225         int i;
5226         int ret = 0;
5227         int num_stripes;
5228         int max_errors = 0;
5229         int tgtdev_indexes = 0;
5230         struct btrfs_bio *bbio = NULL;
5231         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
5232         int dev_replace_is_ongoing = 0;
5233         int num_alloc_stripes;
5234         int patch_the_first_stripe_for_dev_replace = 0;
5235         u64 physical_to_patch_in_first_stripe = 0;
5236         u64 raid56_full_stripe_start = (u64)-1;
5237
5238         read_lock(&em_tree->lock);
5239         em = lookup_extent_mapping(em_tree, logical, *length);
5240         read_unlock(&em_tree->lock);
5241
5242         if (!em) {
5243                 btrfs_crit(fs_info, "unable to find logical %llu len %llu",
5244                         logical, *length);
5245                 return -EINVAL;
5246         }
5247
5248         if (em->start > logical || em->start + em->len < logical) {
5249                 btrfs_crit(fs_info, "found a bad mapping, wanted %Lu, "
5250                            "found %Lu-%Lu", logical, em->start,
5251                            em->start + em->len);
5252                 free_extent_map(em);
5253                 return -EINVAL;
5254         }
5255
5256         map = (struct map_lookup *)em->bdev;
5257         offset = logical - em->start;
5258
5259         stripe_len = map->stripe_len;
5260         stripe_nr = offset;
5261         /*
5262          * stripe_nr counts the total number of stripes we have to stride
5263          * to get to this block
5264          */
5265         stripe_nr = div64_u64(stripe_nr, stripe_len);
5266
5267         stripe_offset = stripe_nr * stripe_len;
5268         BUG_ON(offset < stripe_offset);
5269
5270         /* stripe_offset is the offset of this block in its stripe*/
5271         stripe_offset = offset - stripe_offset;
5272
5273         /* if we're here for raid56, we need to know the stripe aligned start */
5274         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5275                 unsigned long full_stripe_len = stripe_len * nr_data_stripes(map);
5276                 raid56_full_stripe_start = offset;
5277
5278                 /* allow a write of a full stripe, but make sure we don't
5279                  * allow straddling of stripes
5280                  */
5281                 raid56_full_stripe_start = div64_u64(raid56_full_stripe_start,
5282                                 full_stripe_len);
5283                 raid56_full_stripe_start *= full_stripe_len;
5284         }
5285
5286         if (rw & REQ_DISCARD) {
5287                 /* we don't discard raid56 yet */
5288                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5289                         ret = -EOPNOTSUPP;
5290                         goto out;
5291                 }
5292                 *length = min_t(u64, em->len - offset, *length);
5293         } else if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
5294                 u64 max_len;
5295                 /* For writes to RAID[56], allow a full stripeset across all disks.
5296                    For other RAID types and for RAID[56] reads, just allow a single
5297                    stripe (on a single disk). */
5298                 if ((map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) &&
5299                     (rw & REQ_WRITE)) {
5300                         max_len = stripe_len * nr_data_stripes(map) -
5301                                 (offset - raid56_full_stripe_start);
5302                 } else {
5303                         /* we limit the length of each bio to what fits in a stripe */
5304                         max_len = stripe_len - stripe_offset;
5305                 }
5306                 *length = min_t(u64, em->len - offset, max_len);
5307         } else {
5308                 *length = em->len - offset;
5309         }
5310
5311         /* This is for when we're called from btrfs_merge_bio_hook() and all
5312            it cares about is the length */
5313         if (!bbio_ret)
5314                 goto out;
5315
5316         btrfs_dev_replace_lock(dev_replace);
5317         dev_replace_is_ongoing = btrfs_dev_replace_is_ongoing(dev_replace);
5318         if (!dev_replace_is_ongoing)
5319                 btrfs_dev_replace_unlock(dev_replace);
5320
5321         if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
5322             !(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) &&
5323             dev_replace->tgtdev != NULL) {
5324                 /*
5325                  * in dev-replace case, for repair case (that's the only
5326                  * case where the mirror is selected explicitly when
5327                  * calling btrfs_map_block), blocks left of the left cursor
5328                  * can also be read from the target drive.
5329                  * For REQ_GET_READ_MIRRORS, the target drive is added as
5330                  * the last one to the array of stripes. For READ, it also
5331                  * needs to be supported using the same mirror number.
5332                  * If the requested block is not left of the left cursor,
5333                  * EIO is returned. This can happen because btrfs_num_copies()
5334                  * returns one more in the dev-replace case.
5335                  */
5336                 u64 tmp_length = *length;
5337                 struct btrfs_bio *tmp_bbio = NULL;
5338                 int tmp_num_stripes;
5339                 u64 srcdev_devid = dev_replace->srcdev->devid;
5340                 int index_srcdev = 0;
5341                 int found = 0;
5342                 u64 physical_of_found = 0;
5343
5344                 ret = __btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS,
5345                              logical, &tmp_length, &tmp_bbio, 0, 0);
5346                 if (ret) {
5347                         WARN_ON(tmp_bbio != NULL);
5348                         goto out;
5349                 }
5350
5351                 tmp_num_stripes = tmp_bbio->num_stripes;
5352                 if (mirror_num > tmp_num_stripes) {
5353                         /*
5354                          * REQ_GET_READ_MIRRORS does not contain this
5355                          * mirror, that means that the requested area
5356                          * is not left of the left cursor
5357                          */
5358                         ret = -EIO;
5359                         btrfs_put_bbio(tmp_bbio);
5360                         goto out;
5361                 }
5362
5363                 /*
5364                  * process the rest of the function using the mirror_num
5365                  * of the source drive. Therefore look it up first.
5366                  * At the end, patch the device pointer to the one of the
5367                  * target drive.
5368                  */
5369                 for (i = 0; i < tmp_num_stripes; i++) {
5370                         if (tmp_bbio->stripes[i].dev->devid == srcdev_devid) {
5371                                 /*
5372                                  * In case of DUP, in order to keep it
5373                                  * simple, only add the mirror with the
5374                                  * lowest physical address
5375                                  */
5376                                 if (found &&
5377                                     physical_of_found <=
5378                                      tmp_bbio->stripes[i].physical)
5379                                         continue;
5380                                 index_srcdev = i;
5381                                 found = 1;
5382                                 physical_of_found =
5383                                         tmp_bbio->stripes[i].physical;
5384                         }
5385                 }
5386
5387                 if (found) {
5388                         mirror_num = index_srcdev + 1;
5389                         patch_the_first_stripe_for_dev_replace = 1;
5390                         physical_to_patch_in_first_stripe = physical_of_found;
5391                 } else {
5392                         WARN_ON(1);
5393                         ret = -EIO;
5394                         btrfs_put_bbio(tmp_bbio);
5395                         goto out;
5396                 }
5397
5398                 btrfs_put_bbio(tmp_bbio);
5399         } else if (mirror_num > map->num_stripes) {
5400                 mirror_num = 0;
5401         }
5402
5403         num_stripes = 1;
5404         stripe_index = 0;
5405         stripe_nr_orig = stripe_nr;
5406         stripe_nr_end = ALIGN(offset + *length, map->stripe_len);
5407         stripe_nr_end = div_u64(stripe_nr_end, map->stripe_len);
5408         stripe_end_offset = stripe_nr_end * map->stripe_len -
5409                             (offset + *length);
5410
5411         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5412                 if (rw & REQ_DISCARD)
5413                         num_stripes = min_t(u64, map->num_stripes,
5414                                             stripe_nr_end - stripe_nr_orig);
5415                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5416                                 &stripe_index);
5417                 if (!(rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)))
5418                         mirror_num = 1;
5419         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
5420                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS))
5421                         num_stripes = map->num_stripes;
5422                 else if (mirror_num)
5423                         stripe_index = mirror_num - 1;
5424                 else {
5425                         stripe_index = find_live_mirror(fs_info, map, 0,
5426                                             map->num_stripes,
5427                                             current->pid % map->num_stripes,
5428                                             dev_replace_is_ongoing);
5429                         mirror_num = stripe_index + 1;
5430                 }
5431
5432         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
5433                 if (rw & (REQ_WRITE | REQ_DISCARD | REQ_GET_READ_MIRRORS)) {
5434                         num_stripes = map->num_stripes;
5435                 } else if (mirror_num) {
5436                         stripe_index = mirror_num - 1;
5437                 } else {
5438                         mirror_num = 1;
5439                 }
5440
5441         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5442                 u32 factor = map->num_stripes / map->sub_stripes;
5443
5444                 stripe_nr = div_u64_rem(stripe_nr, factor, &stripe_index);
5445                 stripe_index *= map->sub_stripes;
5446
5447                 if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5448                         num_stripes = map->sub_stripes;
5449                 else if (rw & REQ_DISCARD)
5450                         num_stripes = min_t(u64, map->sub_stripes *
5451                                             (stripe_nr_end - stripe_nr_orig),
5452                                             map->num_stripes);
5453                 else if (mirror_num)
5454                         stripe_index += mirror_num - 1;
5455                 else {
5456                         int old_stripe_index = stripe_index;
5457                         stripe_index = find_live_mirror(fs_info, map,
5458                                               stripe_index,
5459                                               map->sub_stripes, stripe_index +
5460                                               current->pid % map->sub_stripes,
5461                                               dev_replace_is_ongoing);
5462                         mirror_num = stripe_index - old_stripe_index + 1;
5463                 }
5464
5465         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5466                 if (need_raid_map &&
5467                     ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5468                      mirror_num > 1)) {
5469                         /* push stripe_nr back to the start of the full stripe */
5470                         stripe_nr = div_u64(raid56_full_stripe_start,
5471                                         stripe_len * nr_data_stripes(map));
5472
5473                         /* RAID[56] write or recovery. Return all stripes */
5474                         num_stripes = map->num_stripes;
5475                         max_errors = nr_parity_stripes(map);
5476
5477                         *length = map->stripe_len;
5478                         stripe_index = 0;
5479                         stripe_offset = 0;
5480                 } else {
5481                         /*
5482                          * Mirror #0 or #1 means the original data block.
5483                          * Mirror #2 is RAID5 parity block.
5484                          * Mirror #3 is RAID6 Q block.
5485                          */
5486                         stripe_nr = div_u64_rem(stripe_nr,
5487                                         nr_data_stripes(map), &stripe_index);
5488                         if (mirror_num > 1)
5489                                 stripe_index = nr_data_stripes(map) +
5490                                                 mirror_num - 2;
5491
5492                         /* We distribute the parity blocks across stripes */
5493                         div_u64_rem(stripe_nr + stripe_index, map->num_stripes,
5494                                         &stripe_index);
5495                         if (!(rw & (REQ_WRITE | REQ_DISCARD |
5496                                     REQ_GET_READ_MIRRORS)) && mirror_num <= 1)
5497                                 mirror_num = 1;
5498                 }
5499         } else {
5500                 /*
5501                  * after this, stripe_nr is the number of stripes on this
5502                  * device we have to walk to find the data, and stripe_index is
5503                  * the number of our device in the stripe array
5504                  */
5505                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes,
5506                                 &stripe_index);
5507                 mirror_num = stripe_index + 1;
5508         }
5509         BUG_ON(stripe_index >= map->num_stripes);
5510
5511         num_alloc_stripes = num_stripes;
5512         if (dev_replace_is_ongoing) {
5513                 if (rw & (REQ_WRITE | REQ_DISCARD))
5514                         num_alloc_stripes <<= 1;
5515                 if (rw & REQ_GET_READ_MIRRORS)
5516                         num_alloc_stripes++;
5517                 tgtdev_indexes = num_stripes;
5518         }
5519
5520         bbio = alloc_btrfs_bio(num_alloc_stripes, tgtdev_indexes);
5521         if (!bbio) {
5522                 ret = -ENOMEM;
5523                 goto out;
5524         }
5525         if (dev_replace_is_ongoing)
5526                 bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
5527
5528         /* build raid_map */
5529         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK &&
5530             need_raid_map && ((rw & (REQ_WRITE | REQ_GET_READ_MIRRORS)) ||
5531             mirror_num > 1)) {
5532                 u64 tmp;
5533                 unsigned rot;
5534
5535                 bbio->raid_map = (u64 *)((void *)bbio->stripes +
5536                                  sizeof(struct btrfs_bio_stripe) *
5537                                  num_alloc_stripes +
5538                                  sizeof(int) * tgtdev_indexes);
5539
5540                 /* Work out the disk rotation on this stripe-set */
5541                 div_u64_rem(stripe_nr, num_stripes, &rot);
5542
5543                 /* Fill in the logical address of each stripe */
5544                 tmp = stripe_nr * nr_data_stripes(map);
5545                 for (i = 0; i < nr_data_stripes(map); i++)
5546                         bbio->raid_map[(i+rot) % num_stripes] =
5547                                 em->start + (tmp + i) * map->stripe_len;
5548
5549                 bbio->raid_map[(i+rot) % map->num_stripes] = RAID5_P_STRIPE;
5550                 if (map->type & BTRFS_BLOCK_GROUP_RAID6)
5551                         bbio->raid_map[(i+rot+1) % num_stripes] =
5552                                 RAID6_Q_STRIPE;
5553         }
5554
5555         if (rw & REQ_DISCARD) {
5556                 u32 factor = 0;
5557                 u32 sub_stripes = 0;
5558                 u64 stripes_per_dev = 0;
5559                 u32 remaining_stripes = 0;
5560                 u32 last_stripe = 0;
5561
5562                 if (map->type &
5563                     (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
5564                         if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5565                                 sub_stripes = 1;
5566                         else
5567                                 sub_stripes = map->sub_stripes;
5568
5569                         factor = map->num_stripes / sub_stripes;
5570                         stripes_per_dev = div_u64_rem(stripe_nr_end -
5571                                                       stripe_nr_orig,
5572                                                       factor,
5573                                                       &remaining_stripes);
5574                         div_u64_rem(stripe_nr_end - 1, factor, &last_stripe);
5575                         last_stripe *= sub_stripes;
5576                 }
5577
5578                 for (i = 0; i < num_stripes; i++) {
5579                         bbio->stripes[i].physical =
5580                                 map->stripes[stripe_index].physical +
5581                                 stripe_offset + stripe_nr * map->stripe_len;
5582                         bbio->stripes[i].dev = map->stripes[stripe_index].dev;
5583
5584                         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 |
5585                                          BTRFS_BLOCK_GROUP_RAID10)) {
5586                                 bbio->stripes[i].length = stripes_per_dev *
5587                                                           map->stripe_len;
5588
5589                                 if (i / sub_stripes < remaining_stripes)
5590                                         bbio->stripes[i].length +=
5591                                                 map->stripe_len;
5592
5593                                 /*
5594                                  * Special for the first stripe and
5595                                  * the last stripe:
5596                                  *
5597                                  * |-------|...|-------|
5598                                  *     |----------|
5599                                  *    off     end_off
5600                                  */
5601                                 if (i < sub_stripes)
5602                                         bbio->stripes[i].length -=
5603                                                 stripe_offset;
5604
5605                                 if (stripe_index >= last_stripe &&
5606                                     stripe_index <= (last_stripe +
5607                                                      sub_stripes - 1))
5608                                         bbio->stripes[i].length -=
5609                                                 stripe_end_offset;
5610
5611                                 if (i == sub_stripes - 1)
5612                                         stripe_offset = 0;
5613                         } else
5614                                 bbio->stripes[i].length = *length;
5615
5616                         stripe_index++;
5617                         if (stripe_index == map->num_stripes) {
5618                                 /* This could only happen for RAID0/10 */
5619                                 stripe_index = 0;
5620                                 stripe_nr++;
5621                         }
5622                 }
5623         } else {
5624                 for (i = 0; i < num_stripes; i++) {
5625                         bbio->stripes[i].physical =
5626                                 map->stripes[stripe_index].physical +
5627                                 stripe_offset +
5628                                 stripe_nr * map->stripe_len;
5629                         bbio->stripes[i].dev =
5630                                 map->stripes[stripe_index].dev;
5631                         stripe_index++;
5632                 }
5633         }
5634
5635         if (rw & (REQ_WRITE | REQ_GET_READ_MIRRORS))
5636                 max_errors = btrfs_chunk_max_errors(map);
5637
5638         if (bbio->raid_map)
5639                 sort_parity_stripes(bbio, num_stripes);
5640
5641         tgtdev_indexes = 0;
5642         if (dev_replace_is_ongoing && (rw & (REQ_WRITE | REQ_DISCARD)) &&
5643             dev_replace->tgtdev != NULL) {
5644                 int index_where_to_add;
5645                 u64 srcdev_devid = dev_replace->srcdev->devid;
5646
5647                 /*
5648                  * duplicate the write operations while the dev replace
5649                  * procedure is running. Since the copying of the old disk
5650                  * to the new disk takes place at run time while the
5651                  * filesystem is mounted writable, the regular write
5652                  * operations to the old disk have to be duplicated to go
5653                  * to the new disk as well.
5654                  * Note that device->missing is handled by the caller, and
5655                  * that the write to the old disk is already set up in the
5656                  * stripes array.
5657                  */
5658                 index_where_to_add = num_stripes;
5659                 for (i = 0; i < num_stripes; i++) {
5660                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5661                                 /* write to new disk, too */
5662                                 struct btrfs_bio_stripe *new =
5663                                         bbio->stripes + index_where_to_add;
5664                                 struct btrfs_bio_stripe *old =
5665                                         bbio->stripes + i;
5666
5667                                 new->physical = old->physical;
5668                                 new->length = old->length;
5669                                 new->dev = dev_replace->tgtdev;
5670                                 bbio->tgtdev_map[i] = index_where_to_add;
5671                                 index_where_to_add++;
5672                                 max_errors++;
5673                                 tgtdev_indexes++;
5674                         }
5675                 }
5676                 num_stripes = index_where_to_add;
5677         } else if (dev_replace_is_ongoing && (rw & REQ_GET_READ_MIRRORS) &&
5678                    dev_replace->tgtdev != NULL) {
5679                 u64 srcdev_devid = dev_replace->srcdev->devid;
5680                 int index_srcdev = 0;
5681                 int found = 0;
5682                 u64 physical_of_found = 0;
5683
5684                 /*
5685                  * During the dev-replace procedure, the target drive can
5686                  * also be used to read data in case it is needed to repair
5687                  * a corrupt block elsewhere. This is possible if the
5688                  * requested area is left of the left cursor. In this area,
5689                  * the target drive is a full copy of the source drive.
5690                  */
5691                 for (i = 0; i < num_stripes; i++) {
5692                         if (bbio->stripes[i].dev->devid == srcdev_devid) {
5693                                 /*
5694                                  * In case of DUP, in order to keep it
5695                                  * simple, only add the mirror with the
5696                                  * lowest physical address
5697                                  */
5698                                 if (found &&
5699                                     physical_of_found <=
5700                                      bbio->stripes[i].physical)
5701                                         continue;
5702                                 index_srcdev = i;
5703                                 found = 1;
5704                                 physical_of_found = bbio->stripes[i].physical;
5705                         }
5706                 }
5707                 if (found) {
5708                         if (physical_of_found + map->stripe_len <=
5709                             dev_replace->cursor_left) {
5710                                 struct btrfs_bio_stripe *tgtdev_stripe =
5711                                         bbio->stripes + num_stripes;
5712
5713                                 tgtdev_stripe->physical = physical_of_found;
5714                                 tgtdev_stripe->length =
5715                                         bbio->stripes[index_srcdev].length;
5716                                 tgtdev_stripe->dev = dev_replace->tgtdev;
5717                                 bbio->tgtdev_map[index_srcdev] = num_stripes;
5718
5719                                 tgtdev_indexes++;
5720                                 num_stripes++;
5721                         }
5722                 }
5723         }
5724
5725         *bbio_ret = bbio;
5726         bbio->map_type = map->type;
5727         bbio->num_stripes = num_stripes;
5728         bbio->max_errors = max_errors;
5729         bbio->mirror_num = mirror_num;
5730         bbio->num_tgtdevs = tgtdev_indexes;
5731
5732         /*
5733          * this is the case that REQ_READ && dev_replace_is_ongoing &&
5734          * mirror_num == num_stripes + 1 && dev_replace target drive is
5735          * available as a mirror
5736          */
5737         if (patch_the_first_stripe_for_dev_replace && num_stripes > 0) {
5738                 WARN_ON(num_stripes > 1);
5739                 bbio->stripes[0].dev = dev_replace->tgtdev;
5740                 bbio->stripes[0].physical = physical_to_patch_in_first_stripe;
5741                 bbio->mirror_num = map->num_stripes + 1;
5742         }
5743 out:
5744         if (dev_replace_is_ongoing)
5745                 btrfs_dev_replace_unlock(dev_replace);
5746         free_extent_map(em);
5747         return ret;
5748 }
5749
5750 int btrfs_map_block(struct btrfs_fs_info *fs_info, int rw,
5751                       u64 logical, u64 *length,
5752                       struct btrfs_bio **bbio_ret, int mirror_num)
5753 {
5754         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5755                                  mirror_num, 0);
5756 }
5757
5758 /* For Scrub/replace */
5759 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, int rw,
5760                      u64 logical, u64 *length,
5761                      struct btrfs_bio **bbio_ret, int mirror_num,
5762                      int need_raid_map)
5763 {
5764         return __btrfs_map_block(fs_info, rw, logical, length, bbio_ret,
5765                                  mirror_num, need_raid_map);
5766 }
5767
5768 int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree,
5769                      u64 chunk_start, u64 physical, u64 devid,
5770                      u64 **logical, int *naddrs, int *stripe_len)
5771 {
5772         struct extent_map_tree *em_tree = &map_tree->map_tree;
5773         struct extent_map *em;
5774         struct map_lookup *map;
5775         u64 *buf;
5776         u64 bytenr;
5777         u64 length;
5778         u64 stripe_nr;
5779         u64 rmap_len;
5780         int i, j, nr = 0;
5781
5782         read_lock(&em_tree->lock);
5783         em = lookup_extent_mapping(em_tree, chunk_start, 1);
5784         read_unlock(&em_tree->lock);
5785
5786         if (!em) {
5787                 printk(KERN_ERR "BTRFS: couldn't find em for chunk %Lu\n",
5788                        chunk_start);
5789                 return -EIO;
5790         }
5791
5792         if (em->start != chunk_start) {
5793                 printk(KERN_ERR "BTRFS: bad chunk start, em=%Lu, wanted=%Lu\n",
5794                        em->start, chunk_start);
5795                 free_extent_map(em);
5796                 return -EIO;
5797         }
5798         map = (struct map_lookup *)em->bdev;
5799
5800         length = em->len;
5801         rmap_len = map->stripe_len;
5802
5803         if (map->type & BTRFS_BLOCK_GROUP_RAID10)
5804                 length = div_u64(length, map->num_stripes / map->sub_stripes);
5805         else if (map->type & BTRFS_BLOCK_GROUP_RAID0)
5806                 length = div_u64(length, map->num_stripes);
5807         else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
5808                 length = div_u64(length, nr_data_stripes(map));
5809                 rmap_len = map->stripe_len * nr_data_stripes(map);
5810         }
5811
5812         buf = kcalloc(map->num_stripes, sizeof(u64), GFP_NOFS);
5813         BUG_ON(!buf); /* -ENOMEM */
5814
5815         for (i = 0; i < map->num_stripes; i++) {
5816                 if (devid && map->stripes[i].dev->devid != devid)
5817                         continue;
5818                 if (map->stripes[i].physical > physical ||
5819                     map->stripes[i].physical + length <= physical)
5820                         continue;
5821
5822                 stripe_nr = physical - map->stripes[i].physical;
5823                 stripe_nr = div_u64(stripe_nr, map->stripe_len);
5824
5825                 if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
5826                         stripe_nr = stripe_nr * map->num_stripes + i;
5827                         stripe_nr = div_u64(stripe_nr, map->sub_stripes);
5828                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
5829                         stripe_nr = stripe_nr * map->num_stripes + i;
5830                 } /* else if RAID[56], multiply by nr_data_stripes().
5831                    * Alternatively, just use rmap_len below instead of
5832                    * map->stripe_len */
5833
5834                 bytenr = chunk_start + stripe_nr * rmap_len;
5835                 WARN_ON(nr >= map->num_stripes);
5836                 for (j = 0; j < nr; j++) {
5837                         if (buf[j] == bytenr)
5838                                 break;
5839                 }
5840                 if (j == nr) {
5841                         WARN_ON(nr >= map->num_stripes);
5842                         buf[nr++] = bytenr;
5843                 }
5844         }
5845
5846         *logical = buf;
5847         *naddrs = nr;
5848         *stripe_len = rmap_len;
5849
5850         free_extent_map(em);
5851         return 0;
5852 }
5853
5854 static inline void btrfs_end_bbio(struct btrfs_bio *bbio, struct bio *bio)
5855 {
5856         bio->bi_private = bbio->private;
5857         bio->bi_end_io = bbio->end_io;
5858         bio_endio(bio);
5859
5860         btrfs_put_bbio(bbio);
5861 }
5862
5863 static void btrfs_end_bio(struct bio *bio)
5864 {
5865         struct btrfs_bio *bbio = bio->bi_private;
5866         int is_orig_bio = 0;
5867
5868         if (bio->bi_error) {
5869                 atomic_inc(&bbio->error);
5870                 if (bio->bi_error == -EIO || bio->bi_error == -EREMOTEIO) {
5871                         unsigned int stripe_index =
5872                                 btrfs_io_bio(bio)->stripe_index;
5873                         struct btrfs_device *dev;
5874
5875                         BUG_ON(stripe_index >= bbio->num_stripes);
5876                         dev = bbio->stripes[stripe_index].dev;
5877                         if (dev->bdev) {
5878                                 if (bio->bi_rw & WRITE)
5879                                         btrfs_dev_stat_inc(dev,
5880                                                 BTRFS_DEV_STAT_WRITE_ERRS);
5881                                 else
5882                                         btrfs_dev_stat_inc(dev,
5883                                                 BTRFS_DEV_STAT_READ_ERRS);
5884                                 if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
5885                                         btrfs_dev_stat_inc(dev,
5886                                                 BTRFS_DEV_STAT_FLUSH_ERRS);
5887                                 btrfs_dev_stat_print_on_error(dev);
5888                         }
5889                 }
5890         }
5891
5892         if (bio == bbio->orig_bio)
5893                 is_orig_bio = 1;
5894
5895         btrfs_bio_counter_dec(bbio->fs_info);
5896
5897         if (atomic_dec_and_test(&bbio->stripes_pending)) {
5898                 if (!is_orig_bio) {
5899                         bio_put(bio);
5900                         bio = bbio->orig_bio;
5901                 }
5902
5903                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
5904                 /* only send an error to the higher layers if it is
5905                  * beyond the tolerance of the btrfs bio
5906                  */
5907                 if (atomic_read(&bbio->error) > bbio->max_errors) {
5908                         bio->bi_error = -EIO;
5909                 } else {
5910                         /*
5911                          * this bio is actually up to date, we didn't
5912                          * go over the max number of errors
5913                          */
5914                         bio->bi_error = 0;
5915                 }
5916
5917                 btrfs_end_bbio(bbio, bio);
5918         } else if (!is_orig_bio) {
5919                 bio_put(bio);
5920         }
5921 }
5922
5923 /*
5924  * see run_scheduled_bios for a description of why bios are collected for
5925  * async submit.
5926  *
5927  * This will add one bio to the pending list for a device and make sure
5928  * the work struct is scheduled.
5929  */
5930 static noinline void btrfs_schedule_bio(struct btrfs_root *root,
5931                                         struct btrfs_device *device,
5932                                         int rw, struct bio *bio)
5933 {
5934         int should_queue = 1;
5935         struct btrfs_pending_bios *pending_bios;
5936
5937         if (device->missing || !device->bdev) {
5938                 bio_io_error(bio);
5939                 return;
5940         }
5941
5942         /* don't bother with additional async steps for reads, right now */
5943         if (!(rw & REQ_WRITE)) {
5944                 bio_get(bio);
5945                 btrfsic_submit_bio(rw, bio);
5946                 bio_put(bio);
5947                 return;
5948         }
5949
5950         /*
5951          * nr_async_bios allows us to reliably return congestion to the
5952          * higher layers.  Otherwise, the async bio makes it appear we have
5953          * made progress against dirty pages when we've really just put it
5954          * on a queue for later
5955          */
5956         atomic_inc(&root->fs_info->nr_async_bios);
5957         WARN_ON(bio->bi_next);
5958         bio->bi_next = NULL;
5959         bio->bi_rw |= rw;
5960
5961         spin_lock(&device->io_lock);
5962         if (bio->bi_rw & REQ_SYNC)
5963                 pending_bios = &device->pending_sync_bios;
5964         else
5965                 pending_bios = &device->pending_bios;
5966
5967         if (pending_bios->tail)
5968                 pending_bios->tail->bi_next = bio;
5969
5970         pending_bios->tail = bio;
5971         if (!pending_bios->head)
5972                 pending_bios->head = bio;
5973         if (device->running_pending)
5974                 should_queue = 0;
5975
5976         spin_unlock(&device->io_lock);
5977
5978         if (should_queue)
5979                 btrfs_queue_work(root->fs_info->submit_workers,
5980                                  &device->work);
5981 }
5982
5983 static void submit_stripe_bio(struct btrfs_root *root, struct btrfs_bio *bbio,
5984                               struct bio *bio, u64 physical, int dev_nr,
5985                               int rw, int async)
5986 {
5987         struct btrfs_device *dev = bbio->stripes[dev_nr].dev;
5988
5989         bio->bi_private = bbio;
5990         btrfs_io_bio(bio)->stripe_index = dev_nr;
5991         bio->bi_end_io = btrfs_end_bio;
5992         bio->bi_iter.bi_sector = physical >> 9;
5993 #ifdef DEBUG
5994         {
5995                 struct rcu_string *name;
5996
5997                 rcu_read_lock();
5998                 name = rcu_dereference(dev->name);
5999                 pr_debug("btrfs_map_bio: rw %d, sector=%llu, dev=%lu "
6000                          "(%s id %llu), size=%u\n", rw,
6001                          (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
6002                          name->str, dev->devid, bio->bi_iter.bi_size);
6003                 rcu_read_unlock();
6004         }
6005 #endif
6006         bio->bi_bdev = dev->bdev;
6007
6008         btrfs_bio_counter_inc_noblocked(root->fs_info);
6009
6010         if (async)
6011                 btrfs_schedule_bio(root, dev, rw, bio);
6012         else
6013                 btrfsic_submit_bio(rw, bio);
6014 }
6015
6016 static void bbio_error(struct btrfs_bio *bbio, struct bio *bio, u64 logical)
6017 {
6018         atomic_inc(&bbio->error);
6019         if (atomic_dec_and_test(&bbio->stripes_pending)) {
6020                 /* Shoud be the original bio. */
6021                 WARN_ON(bio != bbio->orig_bio);
6022
6023                 btrfs_io_bio(bio)->mirror_num = bbio->mirror_num;
6024                 bio->bi_iter.bi_sector = logical >> 9;
6025                 bio->bi_error = -EIO;
6026                 btrfs_end_bbio(bbio, bio);
6027         }
6028 }
6029
6030 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
6031                   int mirror_num, int async_submit)
6032 {
6033         struct btrfs_device *dev;
6034         struct bio *first_bio = bio;
6035         u64 logical = (u64)bio->bi_iter.bi_sector << 9;
6036         u64 length = 0;
6037         u64 map_length;
6038         int ret;
6039         int dev_nr;
6040         int total_devs;
6041         struct btrfs_bio *bbio = NULL;
6042
6043         length = bio->bi_iter.bi_size;
6044         map_length = length;
6045
6046         btrfs_bio_counter_inc_blocked(root->fs_info);
6047         ret = __btrfs_map_block(root->fs_info, rw, logical, &map_length, &bbio,
6048                               mirror_num, 1);
6049         if (ret) {
6050                 btrfs_bio_counter_dec(root->fs_info);
6051                 return ret;
6052         }
6053
6054         total_devs = bbio->num_stripes;
6055         bbio->orig_bio = first_bio;
6056         bbio->private = first_bio->bi_private;
6057         bbio->end_io = first_bio->bi_end_io;
6058         bbio->fs_info = root->fs_info;
6059         atomic_set(&bbio->stripes_pending, bbio->num_stripes);
6060
6061         if (bbio->raid_map) {
6062                 /* In this case, map_length has been set to the length of
6063                    a single stripe; not the whole write */
6064                 if (rw & WRITE) {
6065                         ret = raid56_parity_write(root, bio, bbio, map_length);
6066                 } else {
6067                         ret = raid56_parity_recover(root, bio, bbio, map_length,
6068                                                     mirror_num, 1);
6069                 }
6070
6071                 btrfs_bio_counter_dec(root->fs_info);
6072                 return ret;
6073         }
6074
6075         if (map_length < length) {
6076                 btrfs_crit(root->fs_info, "mapping failed logical %llu bio len %llu len %llu",
6077                         logical, length, map_length);
6078                 BUG();
6079         }
6080
6081         for (dev_nr = 0; dev_nr < total_devs; dev_nr++) {
6082                 dev = bbio->stripes[dev_nr].dev;
6083                 if (!dev || !dev->bdev || (rw & WRITE && !dev->writeable)) {
6084                         bbio_error(bbio, first_bio, logical);
6085                         continue;
6086                 }
6087
6088                 if (dev_nr < total_devs - 1) {
6089                         bio = btrfs_bio_clone(first_bio, GFP_NOFS);
6090                         BUG_ON(!bio); /* -ENOMEM */
6091                 } else
6092                         bio = first_bio;
6093
6094                 submit_stripe_bio(root, bbio, bio,
6095                                   bbio->stripes[dev_nr].physical, dev_nr, rw,
6096                                   async_submit);
6097         }
6098         btrfs_bio_counter_dec(root->fs_info);
6099         return 0;
6100 }
6101
6102 struct btrfs_device *btrfs_find_device(struct btrfs_fs_info *fs_info, u64 devid,
6103                                        u8 *uuid, u8 *fsid)
6104 {
6105         struct btrfs_device *device;
6106         struct btrfs_fs_devices *cur_devices;
6107
6108         cur_devices = fs_info->fs_devices;
6109         while (cur_devices) {
6110                 if (!fsid ||
6111                     !memcmp(cur_devices->fsid, fsid, BTRFS_UUID_SIZE)) {
6112                         device = __find_device(&cur_devices->devices,
6113                                                devid, uuid);
6114                         if (device)
6115                                 return device;
6116                 }
6117                 cur_devices = cur_devices->seed;
6118         }
6119         return NULL;
6120 }
6121
6122 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
6123                                             struct btrfs_fs_devices *fs_devices,
6124                                             u64 devid, u8 *dev_uuid)
6125 {
6126         struct btrfs_device *device;
6127
6128         device = btrfs_alloc_device(NULL, &devid, dev_uuid);
6129         if (IS_ERR(device))
6130                 return NULL;
6131
6132         list_add(&device->dev_list, &fs_devices->devices);
6133         device->fs_devices = fs_devices;
6134         fs_devices->num_devices++;
6135
6136         device->missing = 1;
6137         fs_devices->missing_devices++;
6138
6139         return device;
6140 }
6141
6142 /**
6143  * btrfs_alloc_device - allocate struct btrfs_device
6144  * @fs_info:    used only for generating a new devid, can be NULL if
6145  *              devid is provided (i.e. @devid != NULL).
6146  * @devid:      a pointer to devid for this device.  If NULL a new devid
6147  *              is generated.
6148  * @uuid:       a pointer to UUID for this device.  If NULL a new UUID
6149  *              is generated.
6150  *
6151  * Return: a pointer to a new &struct btrfs_device on success; ERR_PTR()
6152  * on error.  Returned struct is not linked onto any lists and can be
6153  * destroyed with kfree() right away.
6154  */
6155 struct btrfs_device *btrfs_alloc_device(struct btrfs_fs_info *fs_info,
6156                                         const u64 *devid,
6157                                         const u8 *uuid)
6158 {
6159         struct btrfs_device *dev;
6160         u64 tmp;
6161
6162         if (WARN_ON(!devid && !fs_info))
6163                 return ERR_PTR(-EINVAL);
6164
6165         dev = __alloc_device();
6166         if (IS_ERR(dev))
6167                 return dev;
6168
6169         if (devid)
6170                 tmp = *devid;
6171         else {
6172                 int ret;
6173
6174                 ret = find_next_devid(fs_info, &tmp);
6175                 if (ret) {
6176                         kfree(dev);
6177                         return ERR_PTR(ret);
6178                 }
6179         }
6180         dev->devid = tmp;
6181
6182         if (uuid)
6183                 memcpy(dev->uuid, uuid, BTRFS_UUID_SIZE);
6184         else
6185                 generate_random_uuid(dev->uuid);
6186
6187         btrfs_init_work(&dev->work, btrfs_submit_helper,
6188                         pending_bios_fn, NULL, NULL);
6189
6190         return dev;
6191 }
6192
6193 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
6194                           struct extent_buffer *leaf,
6195                           struct btrfs_chunk *chunk)
6196 {
6197         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
6198         struct map_lookup *map;
6199         struct extent_map *em;
6200         u64 logical;
6201         u64 length;
6202         u64 devid;
6203         u8 uuid[BTRFS_UUID_SIZE];
6204         int num_stripes;
6205         int ret;
6206         int i;
6207
6208         logical = key->offset;
6209         length = btrfs_chunk_length(leaf, chunk);
6210
6211         read_lock(&map_tree->map_tree.lock);
6212         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
6213         read_unlock(&map_tree->map_tree.lock);
6214
6215         /* already mapped? */
6216         if (em && em->start <= logical && em->start + em->len > logical) {
6217                 free_extent_map(em);
6218                 return 0;
6219         } else if (em) {
6220                 free_extent_map(em);
6221         }
6222
6223         em = alloc_extent_map();
6224         if (!em)
6225                 return -ENOMEM;
6226         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
6227         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
6228         if (!map) {
6229                 free_extent_map(em);
6230                 return -ENOMEM;
6231         }
6232
6233         set_bit(EXTENT_FLAG_FS_MAPPING, &em->flags);
6234         em->bdev = (struct block_device *)map;
6235         em->start = logical;
6236         em->len = length;
6237         em->orig_start = 0;
6238         em->block_start = 0;
6239         em->block_len = em->len;
6240
6241         map->num_stripes = num_stripes;
6242         map->io_width = btrfs_chunk_io_width(leaf, chunk);
6243         map->io_align = btrfs_chunk_io_align(leaf, chunk);
6244         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
6245         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
6246         map->type = btrfs_chunk_type(leaf, chunk);
6247         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
6248         for (i = 0; i < num_stripes; i++) {
6249                 map->stripes[i].physical =
6250                         btrfs_stripe_offset_nr(leaf, chunk, i);
6251                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
6252                 read_extent_buffer(leaf, uuid, (unsigned long)
6253                                    btrfs_stripe_dev_uuid_nr(chunk, i),
6254                                    BTRFS_UUID_SIZE);
6255                 map->stripes[i].dev = btrfs_find_device(root->fs_info, devid,
6256                                                         uuid, NULL);
6257                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
6258                         free_extent_map(em);
6259                         return -EIO;
6260                 }
6261                 if (!map->stripes[i].dev) {
6262                         map->stripes[i].dev =
6263                                 add_missing_dev(root, root->fs_info->fs_devices,
6264                                                 devid, uuid);
6265                         if (!map->stripes[i].dev) {
6266                                 free_extent_map(em);
6267                                 return -EIO;
6268                         }
6269                         btrfs_warn(root->fs_info, "devid %llu uuid %pU is missing",
6270                                                 devid, uuid);
6271                 }
6272                 map->stripes[i].dev->in_fs_metadata = 1;
6273         }
6274
6275         write_lock(&map_tree->map_tree.lock);
6276         ret = add_extent_mapping(&map_tree->map_tree, em, 0);
6277         write_unlock(&map_tree->map_tree.lock);
6278         BUG_ON(ret); /* Tree corruption */
6279         free_extent_map(em);
6280
6281         return 0;
6282 }
6283
6284 static void fill_device_from_item(struct extent_buffer *leaf,
6285                                  struct btrfs_dev_item *dev_item,
6286                                  struct btrfs_device *device)
6287 {
6288         unsigned long ptr;
6289
6290         device->devid = btrfs_device_id(leaf, dev_item);
6291         device->disk_total_bytes = btrfs_device_total_bytes(leaf, dev_item);
6292         device->total_bytes = device->disk_total_bytes;
6293         device->commit_total_bytes = device->disk_total_bytes;
6294         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
6295         device->commit_bytes_used = device->bytes_used;
6296         device->type = btrfs_device_type(leaf, dev_item);
6297         device->io_align = btrfs_device_io_align(leaf, dev_item);
6298         device->io_width = btrfs_device_io_width(leaf, dev_item);
6299         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
6300         WARN_ON(device->devid == BTRFS_DEV_REPLACE_DEVID);
6301         device->is_tgtdev_for_dev_replace = 0;
6302
6303         ptr = btrfs_device_uuid(dev_item);
6304         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
6305 }
6306
6307 static struct btrfs_fs_devices *open_seed_devices(struct btrfs_root *root,
6308                                                   u8 *fsid)
6309 {
6310         struct btrfs_fs_devices *fs_devices;
6311         int ret;
6312
6313         BUG_ON(!mutex_is_locked(&uuid_mutex));
6314
6315         fs_devices = root->fs_info->fs_devices->seed;
6316         while (fs_devices) {
6317                 if (!memcmp(fs_devices->fsid, fsid, BTRFS_UUID_SIZE))
6318                         return fs_devices;
6319
6320                 fs_devices = fs_devices->seed;
6321         }
6322
6323         fs_devices = find_fsid(fsid);
6324         if (!fs_devices) {
6325                 if (!btrfs_test_opt(root, DEGRADED))
6326                         return ERR_PTR(-ENOENT);
6327
6328                 fs_devices = alloc_fs_devices(fsid);
6329                 if (IS_ERR(fs_devices))
6330                         return fs_devices;
6331
6332                 fs_devices->seeding = 1;
6333                 fs_devices->opened = 1;
6334                 return fs_devices;
6335         }
6336
6337         fs_devices = clone_fs_devices(fs_devices);
6338         if (IS_ERR(fs_devices))
6339                 return fs_devices;
6340
6341         ret = __btrfs_open_devices(fs_devices, FMODE_READ,
6342                                    root->fs_info->bdev_holder);
6343         if (ret) {
6344                 free_fs_devices(fs_devices);
6345                 fs_devices = ERR_PTR(ret);
6346                 goto out;
6347         }
6348
6349         if (!fs_devices->seeding) {
6350                 __btrfs_close_devices(fs_devices);
6351                 free_fs_devices(fs_devices);
6352                 fs_devices = ERR_PTR(-EINVAL);
6353                 goto out;
6354         }
6355
6356         fs_devices->seed = root->fs_info->fs_devices->seed;
6357         root->fs_info->fs_devices->seed = fs_devices;
6358 out:
6359         return fs_devices;
6360 }
6361
6362 static int read_one_dev(struct btrfs_root *root,
6363                         struct extent_buffer *leaf,
6364                         struct btrfs_dev_item *dev_item)
6365 {
6366         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6367         struct btrfs_device *device;
6368         u64 devid;
6369         int ret;
6370         u8 fs_uuid[BTRFS_UUID_SIZE];
6371         u8 dev_uuid[BTRFS_UUID_SIZE];
6372
6373         devid = btrfs_device_id(leaf, dev_item);
6374         read_extent_buffer(leaf, dev_uuid, btrfs_device_uuid(dev_item),
6375                            BTRFS_UUID_SIZE);
6376         read_extent_buffer(leaf, fs_uuid, btrfs_device_fsid(dev_item),
6377                            BTRFS_UUID_SIZE);
6378
6379         if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) {
6380                 fs_devices = open_seed_devices(root, fs_uuid);
6381                 if (IS_ERR(fs_devices))
6382                         return PTR_ERR(fs_devices);
6383         }
6384
6385         device = btrfs_find_device(root->fs_info, devid, dev_uuid, fs_uuid);
6386         if (!device) {
6387                 if (!btrfs_test_opt(root, DEGRADED))
6388                         return -EIO;
6389
6390                 device = add_missing_dev(root, fs_devices, devid, dev_uuid);
6391                 if (!device)
6392                         return -ENOMEM;
6393                 btrfs_warn(root->fs_info, "devid %llu uuid %pU missing",
6394                                 devid, dev_uuid);
6395         } else {
6396                 if (!device->bdev && !btrfs_test_opt(root, DEGRADED))
6397                         return -EIO;
6398
6399                 if(!device->bdev && !device->missing) {
6400                         /*
6401                          * this happens when a device that was properly setup
6402                          * in the device info lists suddenly goes bad.
6403                          * device->bdev is NULL, and so we have to set
6404                          * device->missing to one here
6405                          */
6406                         device->fs_devices->missing_devices++;
6407                         device->missing = 1;
6408                 }
6409
6410                 /* Move the device to its own fs_devices */
6411                 if (device->fs_devices != fs_devices) {
6412                         ASSERT(device->missing);
6413
6414                         list_move(&device->dev_list, &fs_devices->devices);
6415                         device->fs_devices->num_devices--;
6416                         fs_devices->num_devices++;
6417
6418                         device->fs_devices->missing_devices--;
6419                         fs_devices->missing_devices++;
6420
6421                         device->fs_devices = fs_devices;
6422                 }
6423         }
6424
6425         if (device->fs_devices != root->fs_info->fs_devices) {
6426                 BUG_ON(device->writeable);
6427                 if (device->generation !=
6428                     btrfs_device_generation(leaf, dev_item))
6429                         return -EINVAL;
6430         }
6431
6432         fill_device_from_item(leaf, dev_item, device);
6433         device->in_fs_metadata = 1;
6434         if (device->writeable && !device->is_tgtdev_for_dev_replace) {
6435                 device->fs_devices->total_rw_bytes += device->total_bytes;
6436                 spin_lock(&root->fs_info->free_chunk_lock);
6437                 root->fs_info->free_chunk_space += device->total_bytes -
6438                         device->bytes_used;
6439                 spin_unlock(&root->fs_info->free_chunk_lock);
6440         }
6441         ret = 0;
6442         return ret;
6443 }
6444
6445 int btrfs_read_sys_array(struct btrfs_root *root)
6446 {
6447         struct btrfs_super_block *super_copy = root->fs_info->super_copy;
6448         struct extent_buffer *sb;
6449         struct btrfs_disk_key *disk_key;
6450         struct btrfs_chunk *chunk;
6451         u8 *array_ptr;
6452         unsigned long sb_array_offset;
6453         int ret = 0;
6454         u32 num_stripes;
6455         u32 array_size;
6456         u32 len = 0;
6457         u32 cur_offset;
6458         struct btrfs_key key;
6459
6460         ASSERT(BTRFS_SUPER_INFO_SIZE <= root->nodesize);
6461         /*
6462          * This will create extent buffer of nodesize, superblock size is
6463          * fixed to BTRFS_SUPER_INFO_SIZE. If nodesize > sb size, this will
6464          * overallocate but we can keep it as-is, only the first page is used.
6465          */
6466         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET);
6467         if (!sb)
6468                 return -ENOMEM;
6469         btrfs_set_buffer_uptodate(sb);
6470         btrfs_set_buffer_lockdep_class(root->root_key.objectid, sb, 0);
6471         /*
6472          * The sb extent buffer is artifical and just used to read the system array.
6473          * btrfs_set_buffer_uptodate() call does not properly mark all it's
6474          * pages up-to-date when the page is larger: extent does not cover the
6475          * whole page and consequently check_page_uptodate does not find all
6476          * the page's extents up-to-date (the hole beyond sb),
6477          * write_extent_buffer then triggers a WARN_ON.
6478          *
6479          * Regular short extents go through mark_extent_buffer_dirty/writeback cycle,
6480          * but sb spans only this function. Add an explicit SetPageUptodate call
6481          * to silence the warning eg. on PowerPC 64.
6482          */
6483         if (PAGE_CACHE_SIZE > BTRFS_SUPER_INFO_SIZE)
6484                 SetPageUptodate(sb->pages[0]);
6485
6486         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
6487         array_size = btrfs_super_sys_array_size(super_copy);
6488
6489         array_ptr = super_copy->sys_chunk_array;
6490         sb_array_offset = offsetof(struct btrfs_super_block, sys_chunk_array);
6491         cur_offset = 0;
6492
6493         while (cur_offset < array_size) {
6494                 disk_key = (struct btrfs_disk_key *)array_ptr;
6495                 len = sizeof(*disk_key);
6496                 if (cur_offset + len > array_size)
6497                         goto out_short_read;
6498
6499                 btrfs_disk_key_to_cpu(&key, disk_key);
6500
6501                 array_ptr += len;
6502                 sb_array_offset += len;
6503                 cur_offset += len;
6504
6505                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
6506                         chunk = (struct btrfs_chunk *)sb_array_offset;
6507                         /*
6508                          * At least one btrfs_chunk with one stripe must be
6509                          * present, exact stripe count check comes afterwards
6510                          */
6511                         len = btrfs_chunk_item_size(1);
6512                         if (cur_offset + len > array_size)
6513                                 goto out_short_read;
6514
6515                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
6516                         if (!num_stripes) {
6517                                 printk(KERN_ERR
6518             "BTRFS: invalid number of stripes %u in sys_array at offset %u\n",
6519                                         num_stripes, cur_offset);
6520                                 ret = -EIO;
6521                                 break;
6522                         }
6523
6524                         len = btrfs_chunk_item_size(num_stripes);
6525                         if (cur_offset + len > array_size)
6526                                 goto out_short_read;
6527
6528                         ret = read_one_chunk(root, &key, sb, chunk);
6529                         if (ret)
6530                                 break;
6531                 } else {
6532                         ret = -EIO;
6533                         break;
6534                 }
6535                 array_ptr += len;
6536                 sb_array_offset += len;
6537                 cur_offset += len;
6538         }
6539         free_extent_buffer(sb);
6540         return ret;
6541
6542 out_short_read:
6543         printk(KERN_ERR "BTRFS: sys_array too short to read %u bytes at offset %u\n",
6544                         len, cur_offset);
6545         free_extent_buffer(sb);
6546         return -EIO;
6547 }
6548
6549 int btrfs_read_chunk_tree(struct btrfs_root *root)
6550 {
6551         struct btrfs_path *path;
6552         struct extent_buffer *leaf;
6553         struct btrfs_key key;
6554         struct btrfs_key found_key;
6555         int ret;
6556         int slot;
6557
6558         root = root->fs_info->chunk_root;
6559
6560         path = btrfs_alloc_path();
6561         if (!path)
6562                 return -ENOMEM;
6563
6564         mutex_lock(&uuid_mutex);
6565         lock_chunks(root);
6566
6567         /*
6568          * Read all device items, and then all the chunk items. All
6569          * device items are found before any chunk item (their object id
6570          * is smaller than the lowest possible object id for a chunk
6571          * item - BTRFS_FIRST_CHUNK_TREE_OBJECTID).
6572          */
6573         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
6574         key.offset = 0;
6575         key.type = 0;
6576         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
6577         if (ret < 0)
6578                 goto error;
6579         while (1) {
6580                 leaf = path->nodes[0];
6581                 slot = path->slots[0];
6582                 if (slot >= btrfs_header_nritems(leaf)) {
6583                         ret = btrfs_next_leaf(root, path);
6584                         if (ret == 0)
6585                                 continue;
6586                         if (ret < 0)
6587                                 goto error;
6588                         break;
6589                 }
6590                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
6591                 if (found_key.type == BTRFS_DEV_ITEM_KEY) {
6592                         struct btrfs_dev_item *dev_item;
6593                         dev_item = btrfs_item_ptr(leaf, slot,
6594                                                   struct btrfs_dev_item);
6595                         ret = read_one_dev(root, leaf, dev_item);
6596                         if (ret)
6597                                 goto error;
6598                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
6599                         struct btrfs_chunk *chunk;
6600                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
6601                         ret = read_one_chunk(root, &found_key, leaf, chunk);
6602                         if (ret)
6603                                 goto error;
6604                 }
6605                 path->slots[0]++;
6606         }
6607         ret = 0;
6608 error:
6609         unlock_chunks(root);
6610         mutex_unlock(&uuid_mutex);
6611
6612         btrfs_free_path(path);
6613         return ret;
6614 }
6615
6616 void btrfs_init_devices_late(struct btrfs_fs_info *fs_info)
6617 {
6618         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6619         struct btrfs_device *device;
6620
6621         while (fs_devices) {
6622                 mutex_lock(&fs_devices->device_list_mutex);
6623                 list_for_each_entry(device, &fs_devices->devices, dev_list)
6624                         device->dev_root = fs_info->dev_root;
6625                 mutex_unlock(&fs_devices->device_list_mutex);
6626
6627                 fs_devices = fs_devices->seed;
6628         }
6629 }
6630
6631 static void __btrfs_reset_dev_stats(struct btrfs_device *dev)
6632 {
6633         int i;
6634
6635         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6636                 btrfs_dev_stat_reset(dev, i);
6637 }
6638
6639 int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info)
6640 {
6641         struct btrfs_key key;
6642         struct btrfs_key found_key;
6643         struct btrfs_root *dev_root = fs_info->dev_root;
6644         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6645         struct extent_buffer *eb;
6646         int slot;
6647         int ret = 0;
6648         struct btrfs_device *device;
6649         struct btrfs_path *path = NULL;
6650         int i;
6651
6652         path = btrfs_alloc_path();
6653         if (!path) {
6654                 ret = -ENOMEM;
6655                 goto out;
6656         }
6657
6658         mutex_lock(&fs_devices->device_list_mutex);
6659         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6660                 int item_size;
6661                 struct btrfs_dev_stats_item *ptr;
6662
6663                 key.objectid = 0;
6664                 key.type = BTRFS_DEV_STATS_KEY;
6665                 key.offset = device->devid;
6666                 ret = btrfs_search_slot(NULL, dev_root, &key, path, 0, 0);
6667                 if (ret) {
6668                         __btrfs_reset_dev_stats(device);
6669                         device->dev_stats_valid = 1;
6670                         btrfs_release_path(path);
6671                         continue;
6672                 }
6673                 slot = path->slots[0];
6674                 eb = path->nodes[0];
6675                 btrfs_item_key_to_cpu(eb, &found_key, slot);
6676                 item_size = btrfs_item_size_nr(eb, slot);
6677
6678                 ptr = btrfs_item_ptr(eb, slot,
6679                                      struct btrfs_dev_stats_item);
6680
6681                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6682                         if (item_size >= (1 + i) * sizeof(__le64))
6683                                 btrfs_dev_stat_set(device, i,
6684                                         btrfs_dev_stats_value(eb, ptr, i));
6685                         else
6686                                 btrfs_dev_stat_reset(device, i);
6687                 }
6688
6689                 device->dev_stats_valid = 1;
6690                 btrfs_dev_stat_print_on_load(device);
6691                 btrfs_release_path(path);
6692         }
6693         mutex_unlock(&fs_devices->device_list_mutex);
6694
6695 out:
6696         btrfs_free_path(path);
6697         return ret < 0 ? ret : 0;
6698 }
6699
6700 static int update_dev_stat_item(struct btrfs_trans_handle *trans,
6701                                 struct btrfs_root *dev_root,
6702                                 struct btrfs_device *device)
6703 {
6704         struct btrfs_path *path;
6705         struct btrfs_key key;
6706         struct extent_buffer *eb;
6707         struct btrfs_dev_stats_item *ptr;
6708         int ret;
6709         int i;
6710
6711         key.objectid = 0;
6712         key.type = BTRFS_DEV_STATS_KEY;
6713         key.offset = device->devid;
6714
6715         path = btrfs_alloc_path();
6716         BUG_ON(!path);
6717         ret = btrfs_search_slot(trans, dev_root, &key, path, -1, 1);
6718         if (ret < 0) {
6719                 btrfs_warn_in_rcu(dev_root->fs_info,
6720                         "error %d while searching for dev_stats item for device %s",
6721                               ret, rcu_str_deref(device->name));
6722                 goto out;
6723         }
6724
6725         if (ret == 0 &&
6726             btrfs_item_size_nr(path->nodes[0], path->slots[0]) < sizeof(*ptr)) {
6727                 /* need to delete old one and insert a new one */
6728                 ret = btrfs_del_item(trans, dev_root, path);
6729                 if (ret != 0) {
6730                         btrfs_warn_in_rcu(dev_root->fs_info,
6731                                 "delete too small dev_stats item for device %s failed %d",
6732                                       rcu_str_deref(device->name), ret);
6733                         goto out;
6734                 }
6735                 ret = 1;
6736         }
6737
6738         if (ret == 1) {
6739                 /* need to insert a new item */
6740                 btrfs_release_path(path);
6741                 ret = btrfs_insert_empty_item(trans, dev_root, path,
6742                                               &key, sizeof(*ptr));
6743                 if (ret < 0) {
6744                         btrfs_warn_in_rcu(dev_root->fs_info,
6745                                 "insert dev_stats item for device %s failed %d",
6746                                 rcu_str_deref(device->name), ret);
6747                         goto out;
6748                 }
6749         }
6750
6751         eb = path->nodes[0];
6752         ptr = btrfs_item_ptr(eb, path->slots[0], struct btrfs_dev_stats_item);
6753         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6754                 btrfs_set_dev_stats_value(eb, ptr, i,
6755                                           btrfs_dev_stat_read(device, i));
6756         btrfs_mark_buffer_dirty(eb);
6757
6758 out:
6759         btrfs_free_path(path);
6760         return ret;
6761 }
6762
6763 /*
6764  * called from commit_transaction. Writes all changed device stats to disk.
6765  */
6766 int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
6767                         struct btrfs_fs_info *fs_info)
6768 {
6769         struct btrfs_root *dev_root = fs_info->dev_root;
6770         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6771         struct btrfs_device *device;
6772         int stats_cnt;
6773         int ret = 0;
6774
6775         mutex_lock(&fs_devices->device_list_mutex);
6776         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6777                 if (!device->dev_stats_valid || !btrfs_dev_stats_dirty(device))
6778                         continue;
6779
6780                 stats_cnt = atomic_read(&device->dev_stats_ccnt);
6781                 ret = update_dev_stat_item(trans, dev_root, device);
6782                 if (!ret)
6783                         atomic_sub(stats_cnt, &device->dev_stats_ccnt);
6784         }
6785         mutex_unlock(&fs_devices->device_list_mutex);
6786
6787         return ret;
6788 }
6789
6790 void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index)
6791 {
6792         btrfs_dev_stat_inc(dev, index);
6793         btrfs_dev_stat_print_on_error(dev);
6794 }
6795
6796 static void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
6797 {
6798         if (!dev->dev_stats_valid)
6799                 return;
6800         btrfs_err_rl_in_rcu(dev->dev_root->fs_info,
6801                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6802                            rcu_str_deref(dev->name),
6803                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6804                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6805                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6806                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6807                            btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6808 }
6809
6810 static void btrfs_dev_stat_print_on_load(struct btrfs_device *dev)
6811 {
6812         int i;
6813
6814         for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6815                 if (btrfs_dev_stat_read(dev, i) != 0)
6816                         break;
6817         if (i == BTRFS_DEV_STAT_VALUES_MAX)
6818                 return; /* all values == 0, suppress message */
6819
6820         btrfs_info_in_rcu(dev->dev_root->fs_info,
6821                 "bdev %s errs: wr %u, rd %u, flush %u, corrupt %u, gen %u",
6822                rcu_str_deref(dev->name),
6823                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_WRITE_ERRS),
6824                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_READ_ERRS),
6825                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_FLUSH_ERRS),
6826                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_CORRUPTION_ERRS),
6827                btrfs_dev_stat_read(dev, BTRFS_DEV_STAT_GENERATION_ERRS));
6828 }
6829
6830 int btrfs_get_dev_stats(struct btrfs_root *root,
6831                         struct btrfs_ioctl_get_dev_stats *stats)
6832 {
6833         struct btrfs_device *dev;
6834         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
6835         int i;
6836
6837         mutex_lock(&fs_devices->device_list_mutex);
6838         dev = btrfs_find_device(root->fs_info, stats->devid, NULL, NULL);
6839         mutex_unlock(&fs_devices->device_list_mutex);
6840
6841         if (!dev) {
6842                 btrfs_warn(root->fs_info, "get dev_stats failed, device not found");
6843                 return -ENODEV;
6844         } else if (!dev->dev_stats_valid) {
6845                 btrfs_warn(root->fs_info, "get dev_stats failed, not yet valid");
6846                 return -ENODEV;
6847         } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
6848                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
6849                         if (stats->nr_items > i)
6850                                 stats->values[i] =
6851                                         btrfs_dev_stat_read_and_reset(dev, i);
6852                         else
6853                                 btrfs_dev_stat_reset(dev, i);
6854                 }
6855         } else {
6856                 for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
6857                         if (stats->nr_items > i)
6858                                 stats->values[i] = btrfs_dev_stat_read(dev, i);
6859         }
6860         if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
6861                 stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
6862         return 0;
6863 }
6864
6865 void btrfs_scratch_superblocks(struct block_device *bdev, char *device_path)
6866 {
6867         struct buffer_head *bh;
6868         struct btrfs_super_block *disk_super;
6869         int copy_num;
6870
6871         if (!bdev)
6872                 return;
6873
6874         for (copy_num = 0; copy_num < BTRFS_SUPER_MIRROR_MAX;
6875                 copy_num++) {
6876
6877                 if (btrfs_read_dev_one_super(bdev, copy_num, &bh))
6878                         continue;
6879
6880                 disk_super = (struct btrfs_super_block *)bh->b_data;
6881
6882                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
6883                 set_buffer_dirty(bh);
6884                 sync_dirty_buffer(bh);
6885                 brelse(bh);
6886         }
6887
6888         /* Notify udev that device has changed */
6889         btrfs_kobject_uevent(bdev, KOBJ_CHANGE);
6890
6891         /* Update ctime/mtime for device path for libblkid */
6892         update_dev_time(device_path);
6893 }
6894
6895 /*
6896  * Update the size of all devices, which is used for writing out the
6897  * super blocks.
6898  */
6899 void btrfs_update_commit_device_size(struct btrfs_fs_info *fs_info)
6900 {
6901         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6902         struct btrfs_device *curr, *next;
6903
6904         if (list_empty(&fs_devices->resized_devices))
6905                 return;
6906
6907         mutex_lock(&fs_devices->device_list_mutex);
6908         lock_chunks(fs_info->dev_root);
6909         list_for_each_entry_safe(curr, next, &fs_devices->resized_devices,
6910                                  resized_list) {
6911                 list_del_init(&curr->resized_list);
6912                 curr->commit_total_bytes = curr->disk_total_bytes;
6913         }
6914         unlock_chunks(fs_info->dev_root);
6915         mutex_unlock(&fs_devices->device_list_mutex);
6916 }
6917
6918 /* Must be invoked during the transaction commit */
6919 void btrfs_update_commit_device_bytes_used(struct btrfs_root *root,
6920                                         struct btrfs_transaction *transaction)
6921 {
6922         struct extent_map *em;
6923         struct map_lookup *map;
6924         struct btrfs_device *dev;
6925         int i;
6926
6927         if (list_empty(&transaction->pending_chunks))
6928                 return;
6929
6930         /* In order to kick the device replace finish process */
6931         lock_chunks(root);
6932         list_for_each_entry(em, &transaction->pending_chunks, list) {
6933                 map = (struct map_lookup *)em->bdev;
6934
6935                 for (i = 0; i < map->num_stripes; i++) {
6936                         dev = map->stripes[i].dev;
6937                         dev->commit_bytes_used = dev->bytes_used;
6938                 }
6939         }
6940         unlock_chunks(root);
6941 }
6942
6943 void btrfs_set_fs_info_ptr(struct btrfs_fs_info *fs_info)
6944 {
6945         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6946         while (fs_devices) {
6947                 fs_devices->fs_info = fs_info;
6948                 fs_devices = fs_devices->seed;
6949         }
6950 }
6951
6952 void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
6953 {
6954         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6955         while (fs_devices) {
6956                 fs_devices->fs_info = NULL;
6957                 fs_devices = fs_devices->seed;
6958         }
6959 }
6960
6961 void btrfs_close_one_device(struct btrfs_device *device)
6962 {
6963         struct btrfs_fs_devices *fs_devices = device->fs_devices;
6964         struct btrfs_device *new_device;
6965         struct rcu_string *name;
6966
6967         if (device->bdev)
6968                 fs_devices->open_devices--;
6969
6970         if (device->writeable &&
6971             device->devid != BTRFS_DEV_REPLACE_DEVID) {
6972                 list_del_init(&device->dev_alloc_list);
6973                 fs_devices->rw_devices--;
6974         }
6975
6976         if (device->missing)
6977                 fs_devices->missing_devices--;
6978
6979         new_device = btrfs_alloc_device(NULL, &device->devid,
6980                                         device->uuid);
6981         BUG_ON(IS_ERR(new_device)); /* -ENOMEM */
6982
6983         /* Safe because we are under uuid_mutex */
6984         if (device->name) {
6985                 name = rcu_string_strdup(device->name->str, GFP_NOFS);
6986                 BUG_ON(!name); /* -ENOMEM */
6987                 rcu_assign_pointer(new_device->name, name);
6988         }
6989
6990         list_replace_rcu(&device->dev_list, &new_device->dev_list);
6991         new_device->fs_devices = device->fs_devices;
6992
6993         call_rcu(&device->rcu, free_device);
6994 }