kernel/fs/nfs/pnfs.c

   1 /*
   2  *  pNFS functions to call and manage layout drivers.
   3  *
   4  *  Copyright (c) 2002 [year of first publication]
   5  *  The Regents of the University of Michigan
   6  *  All Rights Reserved
   7  *
   8  *  Dean Hildebrand <dhildebz@umich.edu>
   9  *
  10  *  Permission is granted to use, copy, create derivative works, and
  11  *  redistribute this software and such derivative works for any purpose,
  12  *  so long as the name of the University of Michigan is not used in
  13  *  any advertising or publicity pertaining to the use or distribution
  14  *  of this software without specific, written prior authorization. If
  15  *  the above copyright notice or any other identification of the
  16  *  University of Michigan is included in any copy of any portion of
  17  *  this software, then the disclaimer below must also be included.
  18  *
  19  *  This software is provided as is, without representation or warranty
  20  *  of any kind either express or implied, including without limitation
  21  *  the implied warranties of merchantability, fitness for a particular
  22  *  purpose, or noninfringement.  The Regents of the University of
  23  *  Michigan shall not be liable for any damages, including special,
  24  *  indirect, incidental, or consequential damages, with respect to any
  25  *  claim arising out of or in connection with the use of the software,
  26  *  even if it has been or is hereafter advised of the possibility of
  27  *  such damages.
  28  */
  29
  30 #include <linux/nfs_fs.h>
  31 #include <linux/nfs_page.h>
  32 #include <linux/module.h>
  33 #include "internal.h"
  34 #include "pnfs.h"
  35 #include "iostat.h"
  36 #include "nfs4trace.h"
  37 #include "delegation.h"
  38
  39 #define NFSDBG_FACILITY         NFSDBG_PNFS
  40 #define PNFS_LAYOUTGET_RETRY_TIMEOUT (120*HZ)
  41
  42 /* Locking:
  43  *
  44  * pnfs_spinlock:
  45  *      protects pnfs_modules_tbl.
  46  */
  47 static DEFINE_SPINLOCK(pnfs_spinlock);
  48
  49 /*
  50  * pnfs_modules_tbl holds all pnfs modules
  51  */
  52 static LIST_HEAD(pnfs_modules_tbl);
  53
  54 static int
  55 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, nfs4_stateid stateid,
  56                        enum pnfs_iomode iomode, bool sync);
  57
  58 /* Return the registered pnfs layout driver module matching given id */
  59 static struct pnfs_layoutdriver_type *
  60 find_pnfs_driver_locked(u32 id)
  61 {
  62         struct pnfs_layoutdriver_type *local;
  63
  64         list_for_each_entry(local, &pnfs_modules_tbl, pnfs_tblid)
  65                 if (local->id == id)
  66                         goto out;
  67         local = NULL;
  68 out:
  69         dprintk("%s: Searching for id %u, found %p\n", __func__, id, local);
  70         return local;
  71 }
  72
  73 static struct pnfs_layoutdriver_type *
  74 find_pnfs_driver(u32 id)
  75 {
  76         struct pnfs_layoutdriver_type *local;
  77
  78         spin_lock(&pnfs_spinlock);
  79         local = find_pnfs_driver_locked(id);
  80         if (local != NULL && !try_module_get(local->owner)) {
  81                 dprintk("%s: Could not grab reference on module\n", __func__);
  82                 local = NULL;
  83         }
  84         spin_unlock(&pnfs_spinlock);
  85         return local;
  86 }
  87
  88 void
  89 unset_pnfs_layoutdriver(struct nfs_server *nfss)
  90 {
  91         if (nfss->pnfs_curr_ld) {
  92                 if (nfss->pnfs_curr_ld->clear_layoutdriver)
  93                         nfss->pnfs_curr_ld->clear_layoutdriver(nfss);
  94                 /* Decrement the MDS count. Purge the deviceid cache if zero */
  95                 if (atomic_dec_and_test(&nfss->nfs_client->cl_mds_count))
  96                         nfs4_deviceid_purge_client(nfss->nfs_client);
  97                 module_put(nfss->pnfs_curr_ld->owner);
  98         }
  99         nfss->pnfs_curr_ld = NULL;
 100 }
 101
 102 /*
 103  * Try to set the server's pnfs module to the pnfs layout type specified by id.
 104  * Currently only one pNFS layout driver per filesystem is supported.
 105  *
 106  * @id layout type. Zero (illegal layout type) indicates pNFS not in use.
 107  */
 108 void
 109 set_pnfs_layoutdriver(struct nfs_server *server, const struct nfs_fh *mntfh,
 110                       u32 id)
 111 {
 112         struct pnfs_layoutdriver_type *ld_type = NULL;
 113
 114         if (id == 0)
 115                 goto out_no_driver;
 116         if (!(server->nfs_client->cl_exchange_flags &
 117                  (EXCHGID4_FLAG_USE_NON_PNFS | EXCHGID4_FLAG_USE_PNFS_MDS))) {
 118                 printk(KERN_ERR "NFS: %s: id %u cl_exchange_flags 0x%x\n",
 119                         __func__, id, server->nfs_client->cl_exchange_flags);
 120                 goto out_no_driver;
 121         }
 122         ld_type = find_pnfs_driver(id);
 123         if (!ld_type) {
 124                 request_module("%s-%u", LAYOUT_NFSV4_1_MODULE_PREFIX, id);
 125                 ld_type = find_pnfs_driver(id);
 126                 if (!ld_type) {
 127                         dprintk("%s: No pNFS module found for %u.\n",
 128                                 __func__, id);
 129                         goto out_no_driver;
 130                 }
 131         }
 132         server->pnfs_curr_ld = ld_type;
 133         if (ld_type->set_layoutdriver
 134             && ld_type->set_layoutdriver(server, mntfh)) {
 135                 printk(KERN_ERR "NFS: %s: Error initializing pNFS layout "
 136                         "driver %u.\n", __func__, id);
 137                 module_put(ld_type->owner);
 138                 goto out_no_driver;
 139         }
 140         /* Bump the MDS count */
 141         atomic_inc(&server->nfs_client->cl_mds_count);
 142
 143         dprintk("%s: pNFS module for %u set\n", __func__, id);
 144         return;
 145
 146 out_no_driver:
 147         dprintk("%s: Using NFSv4 I/O\n", __func__);
 148         server->pnfs_curr_ld = NULL;
 149 }
 150
 151 int
 152 pnfs_register_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 153 {
 154         int status = -EINVAL;
 155         struct pnfs_layoutdriver_type *tmp;
 156
 157         if (ld_type->id == 0) {
 158                 printk(KERN_ERR "NFS: %s id 0 is reserved\n", __func__);
 159                 return status;
 160         }
 161         if (!ld_type->alloc_lseg || !ld_type->free_lseg) {
 162                 printk(KERN_ERR "NFS: %s Layout driver must provide "
 163                        "alloc_lseg and free_lseg.\n", __func__);
 164                 return status;
 165         }
 166
 167         spin_lock(&pnfs_spinlock);
 168         tmp = find_pnfs_driver_locked(ld_type->id);
 169         if (!tmp) {
 170                 list_add(&ld_type->pnfs_tblid, &pnfs_modules_tbl);
 171                 status = 0;
 172                 dprintk("%s Registering id:%u name:%s\n", __func__, ld_type->id,
 173                         ld_type->name);
 174         } else {
 175                 printk(KERN_ERR "NFS: %s Module with id %d already loaded!\n",
 176                         __func__, ld_type->id);
 177         }
 178         spin_unlock(&pnfs_spinlock);
 179
 180         return status;
 181 }
 182 EXPORT_SYMBOL_GPL(pnfs_register_layoutdriver);
 183
 184 void
 185 pnfs_unregister_layoutdriver(struct pnfs_layoutdriver_type *ld_type)
 186 {
 187         dprintk("%s Deregistering id:%u\n", __func__, ld_type->id);
 188         spin_lock(&pnfs_spinlock);
 189         list_del(&ld_type->pnfs_tblid);
 190         spin_unlock(&pnfs_spinlock);
 191 }
 192 EXPORT_SYMBOL_GPL(pnfs_unregister_layoutdriver);
 193
 194 /*
 195  * pNFS client layout cache
 196  */
 197
 198 /* Need to hold i_lock if caller does not already hold reference */
 199 void
 200 pnfs_get_layout_hdr(struct pnfs_layout_hdr *lo)
 201 {
 202         atomic_inc(&lo->plh_refcount);
 203 }
 204
 205 static struct pnfs_layout_hdr *
 206 pnfs_alloc_layout_hdr(struct inode *ino, gfp_t gfp_flags)
 207 {
 208         struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
 209         return ld->alloc_layout_hdr(ino, gfp_flags);
 210 }
 211
 212 static void
 213 pnfs_free_layout_hdr(struct pnfs_layout_hdr *lo)
 214 {
 215         struct nfs_server *server = NFS_SERVER(lo->plh_inode);
 216         struct pnfs_layoutdriver_type *ld = server->pnfs_curr_ld;
 217
 218         if (!list_empty(&lo->plh_layouts)) {
 219                 struct nfs_client *clp = server->nfs_client;
 220
 221                 spin_lock(&clp->cl_lock);
 222                 list_del_init(&lo->plh_layouts);
 223                 spin_unlock(&clp->cl_lock);
 224         }
 225         put_rpccred(lo->plh_lc_cred);
 226         return ld->free_layout_hdr(lo);
 227 }
 228
 229 static void
 230 pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
 231 {
 232         struct nfs_inode *nfsi = NFS_I(lo->plh_inode);
 233         dprintk("%s: freeing layout cache %p\n", __func__, lo);
 234         nfsi->layout = NULL;
 235         /* Reset MDS Threshold I/O counters */
 236         nfsi->write_io = 0;
 237         nfsi->read_io = 0;
 238 }
 239
 240 void
 241 pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
 242 {
 243         struct inode *inode = lo->plh_inode;
 244
 245         if (atomic_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
 246                 if (!list_empty(&lo->plh_segs))
 247                         WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n");
 248                 pnfs_detach_layout_hdr(lo);
 249                 spin_unlock(&inode->i_lock);
 250                 pnfs_free_layout_hdr(lo);
 251         }
 252 }
 253
 254 static int
 255 pnfs_iomode_to_fail_bit(u32 iomode)
 256 {
 257         return iomode == IOMODE_RW ?
 258                 NFS_LAYOUT_RW_FAILED : NFS_LAYOUT_RO_FAILED;
 259 }
 260
 261 static void
 262 pnfs_layout_set_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 263 {
 264         lo->plh_retry_timestamp = jiffies;
 265         if (!test_and_set_bit(fail_bit, &lo->plh_flags))
 266                 atomic_inc(&lo->plh_refcount);
 267 }
 268
 269 static void
 270 pnfs_layout_clear_fail_bit(struct pnfs_layout_hdr *lo, int fail_bit)
 271 {
 272         if (test_and_clear_bit(fail_bit, &lo->plh_flags))
 273                 atomic_dec(&lo->plh_refcount);
 274 }
 275
 276 static void
 277 pnfs_layout_io_set_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 278 {
 279         struct inode *inode = lo->plh_inode;
 280         struct pnfs_layout_range range = {
 281                 .iomode = iomode,
 282                 .offset = 0,
 283                 .length = NFS4_MAX_UINT64,
 284         };
 285         LIST_HEAD(head);
 286
 287         spin_lock(&inode->i_lock);
 288         pnfs_layout_set_fail_bit(lo, pnfs_iomode_to_fail_bit(iomode));
 289         pnfs_mark_matching_lsegs_invalid(lo, &head, &range);
 290         spin_unlock(&inode->i_lock);
 291         pnfs_free_lseg_list(&head);
 292         dprintk("%s Setting layout IOMODE_%s fail bit\n", __func__,
 293                         iomode == IOMODE_RW ?  "RW" : "READ");
 294 }
 295
 296 static bool
 297 pnfs_layout_io_test_failed(struct pnfs_layout_hdr *lo, u32 iomode)
 298 {
 299         unsigned long start, end;
 300         int fail_bit = pnfs_iomode_to_fail_bit(iomode);
 301
 302         if (test_bit(fail_bit, &lo->plh_flags) == 0)
 303                 return false;
 304         end = jiffies;
 305         start = end - PNFS_LAYOUTGET_RETRY_TIMEOUT;
 306         if (!time_in_range(lo->plh_retry_timestamp, start, end)) {
 307                 /* It is time to retry the failed layoutgets */
 308                 pnfs_layout_clear_fail_bit(lo, fail_bit);
 309                 return false;
 310         }
 311         return true;
 312 }
 313
 314 static void
 315 init_lseg(struct pnfs_layout_hdr *lo, struct pnfs_layout_segment *lseg)
 316 {
 317         INIT_LIST_HEAD(&lseg->pls_list);
 318         INIT_LIST_HEAD(&lseg->pls_lc_list);
 319         atomic_set(&lseg->pls_refcount, 1);
 320         smp_mb();
 321         set_bit(NFS_LSEG_VALID, &lseg->pls_flags);
 322         lseg->pls_layout = lo;
 323 }
 324
 325 static void pnfs_free_lseg(struct pnfs_layout_segment *lseg)
 326 {
 327         struct inode *ino = lseg->pls_layout->plh_inode;
 328
 329         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
 330 }
 331
 332 static void
 333 pnfs_layout_remove_lseg(struct pnfs_layout_hdr *lo,
 334                 struct pnfs_layout_segment *lseg)
 335 {
 336         struct inode *inode = lo->plh_inode;
 337
 338         WARN_ON(test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 339         list_del_init(&lseg->pls_list);
 340         /* Matched by pnfs_get_layout_hdr in pnfs_layout_insert_lseg */
 341         atomic_dec(&lo->plh_refcount);
 342         if (list_empty(&lo->plh_segs))
 343                 clear_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
 344         rpc_wake_up(&NFS_SERVER(inode)->roc_rpcwaitq);
 345 }
 346
 347 /* Return true if layoutreturn is needed */
 348 static bool
 349 pnfs_layout_need_return(struct pnfs_layout_hdr *lo,
 350                         struct pnfs_layout_segment *lseg)
 351 {
 352         struct pnfs_layout_segment *s;
 353
 354         if (!test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
 355                 return false;
 356
 357         list_for_each_entry(s, &lo->plh_segs, pls_list)
 358                 if (s != lseg && test_bit(NFS_LSEG_LAYOUTRETURN, &s->pls_flags))
 359                         return false;
 360
 361         return true;
 362 }
 363
 364 static void pnfs_layoutreturn_before_put_lseg(struct pnfs_layout_segment *lseg,
 365                 struct pnfs_layout_hdr *lo, struct inode *inode)
 366 {
 367         lo = lseg->pls_layout;
 368         inode = lo->plh_inode;
 369
 370         spin_lock(&inode->i_lock);
 371         if (pnfs_layout_need_return(lo, lseg)) {
 372                 nfs4_stateid stateid;
 373                 enum pnfs_iomode iomode;
 374
 375                 stateid = lo->plh_stateid;
 376                 iomode = lo->plh_return_iomode;
 377                 /* decreased in pnfs_send_layoutreturn() */
 378                 lo->plh_block_lgets++;
 379                 lo->plh_return_iomode = 0;
 380                 spin_unlock(&inode->i_lock);
 381                 pnfs_get_layout_hdr(lo);
 382
 383                 /* Send an async layoutreturn so we dont deadlock */
 384                 pnfs_send_layoutreturn(lo, stateid, iomode, false);
 385         } else
 386                 spin_unlock(&inode->i_lock);
 387 }
 388
 389 void
 390 pnfs_put_lseg(struct pnfs_layout_segment *lseg)
 391 {
 392         struct pnfs_layout_hdr *lo;
 393         struct inode *inode;
 394
 395         if (!lseg)
 396                 return;
 397
 398         dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
 399                 atomic_read(&lseg->pls_refcount),
 400                 test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 401
 402         /* Handle the case where refcount != 1 */
 403         if (atomic_add_unless(&lseg->pls_refcount, -1, 1))
 404                 return;
 405
 406         lo = lseg->pls_layout;
 407         inode = lo->plh_inode;
 408         /* Do we need a layoutreturn? */
 409         if (test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags))
 410                 pnfs_layoutreturn_before_put_lseg(lseg, lo, inode);
 411
 412         if (atomic_dec_and_lock(&lseg->pls_refcount, &inode->i_lock)) {
 413                 pnfs_get_layout_hdr(lo);
 414                 pnfs_layout_remove_lseg(lo, lseg);
 415                 spin_unlock(&inode->i_lock);
 416                 pnfs_free_lseg(lseg);
 417                 pnfs_put_layout_hdr(lo);
 418         }
 419 }
 420 EXPORT_SYMBOL_GPL(pnfs_put_lseg);
 421
 422 static void pnfs_free_lseg_async_work(struct work_struct *work)
 423 {
 424         struct pnfs_layout_segment *lseg;
 425         struct pnfs_layout_hdr *lo;
 426
 427         lseg = container_of(work, struct pnfs_layout_segment, pls_work);
 428         lo = lseg->pls_layout;
 429
 430         pnfs_free_lseg(lseg);
 431         pnfs_put_layout_hdr(lo);
 432 }
 433
 434 static void pnfs_free_lseg_async(struct pnfs_layout_segment *lseg)
 435 {
 436         INIT_WORK(&lseg->pls_work, pnfs_free_lseg_async_work);
 437         schedule_work(&lseg->pls_work);
 438 }
 439
 440 void
 441 pnfs_put_lseg_locked(struct pnfs_layout_segment *lseg)
 442 {
 443         if (!lseg)
 444                 return;
 445
 446         assert_spin_locked(&lseg->pls_layout->plh_inode->i_lock);
 447
 448         dprintk("%s: lseg %p ref %d valid %d\n", __func__, lseg,
 449                 atomic_read(&lseg->pls_refcount),
 450                 test_bit(NFS_LSEG_VALID, &lseg->pls_flags));
 451         if (atomic_dec_and_test(&lseg->pls_refcount)) {
 452                 struct pnfs_layout_hdr *lo = lseg->pls_layout;
 453                 pnfs_get_layout_hdr(lo);
 454                 pnfs_layout_remove_lseg(lo, lseg);
 455                 pnfs_free_lseg_async(lseg);
 456         }
 457 }
 458 EXPORT_SYMBOL_GPL(pnfs_put_lseg_locked);
 459
 460 static u64
 461 end_offset(u64 start, u64 len)
 462 {
 463         u64 end;
 464
 465         end = start + len;
 466         return end >= start ? end : NFS4_MAX_UINT64;
 467 }
 468
 469 /*
 470  * is l2 fully contained in l1?
 471  *   start1                             end1
 472  *   [----------------------------------)
 473  *           start2           end2
 474  *           [----------------)
 475  */
 476 static bool
 477 pnfs_lseg_range_contained(const struct pnfs_layout_range *l1,
 478                  const struct pnfs_layout_range *l2)
 479 {
 480         u64 start1 = l1->offset;
 481         u64 end1 = end_offset(start1, l1->length);
 482         u64 start2 = l2->offset;
 483         u64 end2 = end_offset(start2, l2->length);
 484
 485         return (start1 <= start2) && (end1 >= end2);
 486 }
 487
 488 /*
 489  * is l1 and l2 intersecting?
 490  *   start1                             end1
 491  *   [----------------------------------)
 492  *                              start2           end2
 493  *                              [----------------)
 494  */
 495 static bool
 496 pnfs_lseg_range_intersecting(const struct pnfs_layout_range *l1,
 497                     const struct pnfs_layout_range *l2)
 498 {
 499         u64 start1 = l1->offset;
 500         u64 end1 = end_offset(start1, l1->length);
 501         u64 start2 = l2->offset;
 502         u64 end2 = end_offset(start2, l2->length);
 503
 504         return (end1 == NFS4_MAX_UINT64 || end1 > start2) &&
 505                (end2 == NFS4_MAX_UINT64 || end2 > start1);
 506 }
 507
 508 static bool
 509 should_free_lseg(const struct pnfs_layout_range *lseg_range,
 510                  const struct pnfs_layout_range *recall_range)
 511 {
 512         return (recall_range->iomode == IOMODE_ANY ||
 513                 lseg_range->iomode == recall_range->iomode) &&
 514                pnfs_lseg_range_intersecting(lseg_range, recall_range);
 515 }
 516
 517 static bool pnfs_lseg_dec_and_remove_zero(struct pnfs_layout_segment *lseg,
 518                 struct list_head *tmp_list)
 519 {
 520         if (!atomic_dec_and_test(&lseg->pls_refcount))
 521                 return false;
 522         pnfs_layout_remove_lseg(lseg->pls_layout, lseg);
 523         list_add(&lseg->pls_list, tmp_list);
 524         return true;
 525 }
 526
 527 /* Returns 1 if lseg is removed from list, 0 otherwise */
 528 static int mark_lseg_invalid(struct pnfs_layout_segment *lseg,
 529                              struct list_head *tmp_list)
 530 {
 531         int rv = 0;
 532
 533         if (test_and_clear_bit(NFS_LSEG_VALID, &lseg->pls_flags)) {
 534                 /* Remove the reference keeping the lseg in the
 535                  * list.  It will now be removed when all
 536                  * outstanding io is finished.
 537                  */
 538                 dprintk("%s: lseg %p ref %d\n", __func__, lseg,
 539                         atomic_read(&lseg->pls_refcount));
 540                 if (pnfs_lseg_dec_and_remove_zero(lseg, tmp_list))
 541                         rv = 1;
 542         }
 543         return rv;
 544 }
 545
 546 /* Returns count of number of matching invalid lsegs remaining in list
 547  * after call.
 548  */
 549 int
 550 pnfs_mark_matching_lsegs_invalid(struct pnfs_layout_hdr *lo,
 551                             struct list_head *tmp_list,
 552                             struct pnfs_layout_range *recall_range)
 553 {
 554         struct pnfs_layout_segment *lseg, *next;
 555         int invalid = 0, removed = 0;
 556
 557         dprintk("%s:Begin lo %p\n", __func__, lo);
 558
 559         if (list_empty(&lo->plh_segs))
 560                 return 0;
 561         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
 562                 if (!recall_range ||
 563                     should_free_lseg(&lseg->pls_range, recall_range)) {
 564                         dprintk("%s: freeing lseg %p iomode %d "
 565                                 "offset %llu length %llu\n", __func__,
 566                                 lseg, lseg->pls_range.iomode, lseg->pls_range.offset,
 567                                 lseg->pls_range.length);
 568                         invalid++;
 569                         removed += mark_lseg_invalid(lseg, tmp_list);
 570                 }
 571         dprintk("%s:Return %i\n", __func__, invalid - removed);
 572         return invalid - removed;
 573 }
 574
 575 /* note free_me must contain lsegs from a single layout_hdr */
 576 void
 577 pnfs_free_lseg_list(struct list_head *free_me)
 578 {
 579         struct pnfs_layout_segment *lseg, *tmp;
 580
 581         if (list_empty(free_me))
 582                 return;
 583
 584         list_for_each_entry_safe(lseg, tmp, free_me, pls_list) {
 585                 list_del(&lseg->pls_list);
 586                 pnfs_free_lseg(lseg);
 587         }
 588 }
 589
 590 void
 591 pnfs_destroy_layout(struct nfs_inode *nfsi)
 592 {
 593         struct pnfs_layout_hdr *lo;
 594         LIST_HEAD(tmp_list);
 595
 596         spin_lock(&nfsi->vfs_inode.i_lock);
 597         lo = nfsi->layout;
 598         if (lo) {
 599                 lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
 600                 pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
 601                 pnfs_get_layout_hdr(lo);
 602                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
 603                 pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
 604                 pnfs_clear_retry_layoutget(lo);
 605                 spin_unlock(&nfsi->vfs_inode.i_lock);
 606                 pnfs_free_lseg_list(&tmp_list);
 607                 pnfs_put_layout_hdr(lo);
 608         } else
 609                 spin_unlock(&nfsi->vfs_inode.i_lock);
 610 }
 611 EXPORT_SYMBOL_GPL(pnfs_destroy_layout);
 612
 613 static bool
 614 pnfs_layout_add_bulk_destroy_list(struct inode *inode,
 615                 struct list_head *layout_list)
 616 {
 617         struct pnfs_layout_hdr *lo;
 618         bool ret = false;
 619
 620         spin_lock(&inode->i_lock);
 621         lo = NFS_I(inode)->layout;
 622         if (lo != NULL && list_empty(&lo->plh_bulk_destroy)) {
 623                 pnfs_get_layout_hdr(lo);
 624                 list_add(&lo->plh_bulk_destroy, layout_list);
 625                 ret = true;
 626         }
 627         spin_unlock(&inode->i_lock);
 628         return ret;
 629 }
 630
 631 /* Caller must hold rcu_read_lock and clp->cl_lock */
 632 static int
 633 pnfs_layout_bulk_destroy_byserver_locked(struct nfs_client *clp,
 634                 struct nfs_server *server,
 635                 struct list_head *layout_list)
 636 {
 637         struct pnfs_layout_hdr *lo, *next;
 638         struct inode *inode;
 639
 640         list_for_each_entry_safe(lo, next, &server->layouts, plh_layouts) {
 641                 inode = igrab(lo->plh_inode);
 642                 if (inode == NULL)
 643                         continue;
 644                 list_del_init(&lo->plh_layouts);
 645                 if (pnfs_layout_add_bulk_destroy_list(inode, layout_list))
 646                         continue;
 647                 rcu_read_unlock();
 648                 spin_unlock(&clp->cl_lock);
 649                 iput(inode);
 650                 spin_lock(&clp->cl_lock);
 651                 rcu_read_lock();
 652                 return -EAGAIN;
 653         }
 654         return 0;
 655 }
 656
 657 static int
 658 pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
 659                 bool is_bulk_recall)
 660 {
 661         struct pnfs_layout_hdr *lo;
 662         struct inode *inode;
 663         struct pnfs_layout_range range = {
 664                 .iomode = IOMODE_ANY,
 665                 .offset = 0,
 666                 .length = NFS4_MAX_UINT64,
 667         };
 668         LIST_HEAD(lseg_list);
 669         int ret = 0;
 670
 671         while (!list_empty(layout_list)) {
 672                 lo = list_entry(layout_list->next, struct pnfs_layout_hdr,
 673                                 plh_bulk_destroy);
 674                 dprintk("%s freeing layout for inode %lu\n", __func__,
 675                         lo->plh_inode->i_ino);
 676                 inode = lo->plh_inode;
 677
 678                 pnfs_layoutcommit_inode(inode, false);
 679
 680                 spin_lock(&inode->i_lock);
 681                 list_del_init(&lo->plh_bulk_destroy);
 682                 lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
 683                 if (is_bulk_recall)
 684                         set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
 685                 if (pnfs_mark_matching_lsegs_invalid(lo, &lseg_list, &range))
 686                         ret = -EAGAIN;
 687                 spin_unlock(&inode->i_lock);
 688                 pnfs_free_lseg_list(&lseg_list);
 689                 pnfs_put_layout_hdr(lo);
 690                 iput(inode);
 691         }
 692         return ret;
 693 }
 694
 695 int
 696 pnfs_destroy_layouts_byfsid(struct nfs_client *clp,
 697                 struct nfs_fsid *fsid,
 698                 bool is_recall)
 699 {
 700         struct nfs_server *server;
 701         LIST_HEAD(layout_list);
 702
 703         spin_lock(&clp->cl_lock);
 704         rcu_read_lock();
 705 restart:
 706         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 707                 if (memcmp(&server->fsid, fsid, sizeof(*fsid)) != 0)
 708                         continue;
 709                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
 710                                 server,
 711                                 &layout_list) != 0)
 712                         goto restart;
 713         }
 714         rcu_read_unlock();
 715         spin_unlock(&clp->cl_lock);
 716
 717         if (list_empty(&layout_list))
 718                 return 0;
 719         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
 720 }
 721
 722 int
 723 pnfs_destroy_layouts_byclid(struct nfs_client *clp,
 724                 bool is_recall)
 725 {
 726         struct nfs_server *server;
 727         LIST_HEAD(layout_list);
 728
 729         spin_lock(&clp->cl_lock);
 730         rcu_read_lock();
 731 restart:
 732         list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) {
 733                 if (pnfs_layout_bulk_destroy_byserver_locked(clp,
 734                                         server,
 735                                         &layout_list) != 0)
 736                         goto restart;
 737         }
 738         rcu_read_unlock();
 739         spin_unlock(&clp->cl_lock);
 740
 741         if (list_empty(&layout_list))
 742                 return 0;
 743         return pnfs_layout_free_bulk_destroy_list(&layout_list, is_recall);
 744 }
 745
 746 /*
 747  * Called by the state manger to remove all layouts established under an
 748  * expired lease.
 749  */
 750 void
 751 pnfs_destroy_all_layouts(struct nfs_client *clp)
 752 {
 753         nfs4_deviceid_mark_client_invalid(clp);
 754         nfs4_deviceid_purge_client(clp);
 755
 756         pnfs_destroy_layouts_byclid(clp, false);
 757 }
 758
 759 /*
 760  * Compare 2 layout stateid sequence ids, to see which is newer,
 761  * taking into account wraparound issues.
 762  */
 763 static bool pnfs_seqid_is_newer(u32 s1, u32 s2)
 764 {
 765         return (s32)(s1 - s2) > 0;
 766 }
 767
 768 /* update lo->plh_stateid with new if is more recent */
 769 void
 770 pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
 771                         bool update_barrier)
 772 {
 773         u32 oldseq, newseq, new_barrier;
 774         int empty = list_empty(&lo->plh_segs);
 775
 776         oldseq = be32_to_cpu(lo->plh_stateid.seqid);
 777         newseq = be32_to_cpu(new->seqid);
 778         if (empty || pnfs_seqid_is_newer(newseq, oldseq)) {
 779                 nfs4_stateid_copy(&lo->plh_stateid, new);
 780                 if (update_barrier) {
 781                         new_barrier = be32_to_cpu(new->seqid);
 782                 } else {
 783                         /* Because of wraparound, we want to keep the barrier
 784                          * "close" to the current seqids.
 785                          */
 786                         new_barrier = newseq - atomic_read(&lo->plh_outstanding);
 787                 }
 788                 if (empty || pnfs_seqid_is_newer(new_barrier, lo->plh_barrier))
 789                         lo->plh_barrier = new_barrier;
 790         }
 791 }
 792
 793 static bool
 794 pnfs_layout_stateid_blocked(const struct pnfs_layout_hdr *lo,
 795                 const nfs4_stateid *stateid)
 796 {
 797         u32 seqid = be32_to_cpu(stateid->seqid);
 798
 799         return !pnfs_seqid_is_newer(seqid, lo->plh_barrier);
 800 }
 801
 802 static bool
 803 pnfs_layout_returning(const struct pnfs_layout_hdr *lo,
 804                       struct pnfs_layout_range *range)
 805 {
 806         return test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags) &&
 807                 (lo->plh_return_iomode == IOMODE_ANY ||
 808                  lo->plh_return_iomode == range->iomode);
 809 }
 810
 811 /* lget is set to 1 if called from inside send_layoutget call chain */
 812 static bool
 813 pnfs_layoutgets_blocked(const struct pnfs_layout_hdr *lo,
 814                         struct pnfs_layout_range *range, int lget)
 815 {
 816         return lo->plh_block_lgets ||
 817                 test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags) ||
 818                 (list_empty(&lo->plh_segs) &&
 819                  (atomic_read(&lo->plh_outstanding) > lget)) ||
 820                 pnfs_layout_returning(lo, range);
 821 }
 822
 823 int
 824 pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
 825                               struct pnfs_layout_range *range,
 826                               struct nfs4_state *open_state)
 827 {
 828         int status = 0;
 829
 830         dprintk("--> %s\n", __func__);
 831         spin_lock(&lo->plh_inode->i_lock);
 832         if (pnfs_layoutgets_blocked(lo, range, 1)) {
 833                 status = -EAGAIN;
 834         } else if (!nfs4_valid_open_stateid(open_state)) {
 835                 status = -EBADF;
 836         } else if (list_empty(&lo->plh_segs) ||
 837                    test_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags)) {
 838                 int seq;
 839
 840                 do {
 841                         seq = read_seqbegin(&open_state->seqlock);
 842                         nfs4_stateid_copy(dst, &open_state->stateid);
 843                 } while (read_seqretry(&open_state->seqlock, seq));
 844         } else
 845                 nfs4_stateid_copy(dst, &lo->plh_stateid);
 846         spin_unlock(&lo->plh_inode->i_lock);
 847         dprintk("<-- %s\n", __func__);
 848         return status;
 849 }
 850
 851 /*
 852 * Get layout from server.
 853 *    for now, assume that whole file layouts are requested.
 854 *    arg->offset: 0
 855 *    arg->length: all ones
 856 */
 857 static struct pnfs_layout_segment *
 858 send_layoutget(struct pnfs_layout_hdr *lo,
 859            struct nfs_open_context *ctx,
 860            struct pnfs_layout_range *range,
 861            gfp_t gfp_flags)
 862 {
 863         struct inode *ino = lo->plh_inode;
 864         struct nfs_server *server = NFS_SERVER(ino);
 865         struct nfs4_layoutget *lgp;
 866         struct pnfs_layout_segment *lseg;
 867
 868         dprintk("--> %s\n", __func__);
 869
 870         lgp = kzalloc(sizeof(*lgp), gfp_flags);
 871         if (lgp == NULL)
 872                 return NULL;
 873
 874         lgp->args.minlength = PAGE_CACHE_SIZE;
 875         if (lgp->args.minlength > range->length)
 876                 lgp->args.minlength = range->length;
 877         lgp->args.maxcount = PNFS_LAYOUT_MAXSIZE;
 878         lgp->args.range = *range;
 879         lgp->args.type = server->pnfs_curr_ld->id;
 880         lgp->args.inode = ino;
 881         lgp->args.ctx = get_nfs_open_context(ctx);
 882         lgp->gfp_flags = gfp_flags;
 883         lgp->cred = lo->plh_lc_cred;
 884
 885         /* Synchronously retrieve layout information from server and
 886          * store in lseg.
 887          */
 888         lseg = nfs4_proc_layoutget(lgp, gfp_flags);
 889         if (IS_ERR(lseg)) {
 890                 switch (PTR_ERR(lseg)) {
 891                 case -ENOMEM:
 892                 case -ERESTARTSYS:
 893                         break;
 894                 default:
 895                         /* remember that LAYOUTGET failed and suspend trying */
 896                         pnfs_layout_io_set_failed(lo, range->iomode);
 897                 }
 898                 return NULL;
 899         } else
 900                 pnfs_layout_clear_fail_bit(lo,
 901                                 pnfs_iomode_to_fail_bit(range->iomode));
 902
 903         return lseg;
 904 }
 905
 906 static void pnfs_clear_layoutcommit(struct inode *inode,
 907                 struct list_head *head)
 908 {
 909         struct nfs_inode *nfsi = NFS_I(inode);
 910         struct pnfs_layout_segment *lseg, *tmp;
 911
 912         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
 913                 return;
 914         list_for_each_entry_safe(lseg, tmp, &nfsi->layout->plh_segs, pls_list) {
 915                 if (!test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
 916                         continue;
 917                 pnfs_lseg_dec_and_remove_zero(lseg, head);
 918         }
 919 }
 920
 921 void pnfs_clear_layoutreturn_waitbit(struct pnfs_layout_hdr *lo)
 922 {
 923         clear_bit_unlock(NFS_LAYOUT_RETURN, &lo->plh_flags);
 924         smp_mb__after_atomic();
 925         wake_up_bit(&lo->plh_flags, NFS_LAYOUT_RETURN);
 926 }
 927
 928 static int
 929 pnfs_send_layoutreturn(struct pnfs_layout_hdr *lo, nfs4_stateid stateid,
 930                        enum pnfs_iomode iomode, bool sync)
 931 {
 932         struct inode *ino = lo->plh_inode;
 933         struct nfs4_layoutreturn *lrp;
 934         int status = 0;
 935
 936         lrp = kzalloc(sizeof(*lrp), GFP_NOFS);
 937         if (unlikely(lrp == NULL)) {
 938                 status = -ENOMEM;
 939                 spin_lock(&ino->i_lock);
 940                 lo->plh_block_lgets--;
 941                 pnfs_clear_layoutreturn_waitbit(lo);
 942                 rpc_wake_up(&NFS_SERVER(ino)->roc_rpcwaitq);
 943                 spin_unlock(&ino->i_lock);
 944                 pnfs_put_layout_hdr(lo);
 945                 goto out;
 946         }
 947
 948         lrp->args.stateid = stateid;
 949         lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
 950         lrp->args.inode = ino;
 951         lrp->args.range.iomode = iomode;
 952         lrp->args.range.offset = 0;
 953         lrp->args.range.length = NFS4_MAX_UINT64;
 954         lrp->args.layout = lo;
 955         lrp->clp = NFS_SERVER(ino)->nfs_client;
 956         lrp->cred = lo->plh_lc_cred;
 957
 958         status = nfs4_proc_layoutreturn(lrp, sync);
 959 out:
 960         dprintk("<-- %s status: %d\n", __func__, status);
 961         return status;
 962 }
 963
 964 /*
 965  * Initiates a LAYOUTRETURN(FILE), and removes the pnfs_layout_hdr
 966  * when the layout segment list is empty.
 967  *
 968  * Note that a pnfs_layout_hdr can exist with an empty layout segment
 969  * list when LAYOUTGET has failed, or when LAYOUTGET succeeded, but the
 970  * deviceid is marked invalid.
 971  */
 972 int
 973 _pnfs_return_layout(struct inode *ino)
 974 {
 975         struct pnfs_layout_hdr *lo = NULL;
 976         struct nfs_inode *nfsi = NFS_I(ino);
 977         LIST_HEAD(tmp_list);
 978         nfs4_stateid stateid;
 979         int status = 0, empty;
 980
 981         dprintk("NFS: %s for inode %lu\n", __func__, ino->i_ino);
 982
 983         spin_lock(&ino->i_lock);
 984         lo = nfsi->layout;
 985         if (!lo) {
 986                 spin_unlock(&ino->i_lock);
 987                 dprintk("NFS: %s no layout to return\n", __func__);
 988                 goto out;
 989         }
 990         stateid = nfsi->layout->plh_stateid;
 991         /* Reference matched in nfs4_layoutreturn_release */
 992         pnfs_get_layout_hdr(lo);
 993         empty = list_empty(&lo->plh_segs);
 994         pnfs_clear_layoutcommit(ino, &tmp_list);
 995         pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
 996
 997         if (NFS_SERVER(ino)->pnfs_curr_ld->return_range) {
 998                 struct pnfs_layout_range range = {
 999                         .iomode         = IOMODE_ANY,
1000                         .offset         = 0,
1001                         .length         = NFS4_MAX_UINT64,
1002                 };
1003                 NFS_SERVER(ino)->pnfs_curr_ld->return_range(lo, &range);
1004         }
1005
1006         /* Don't send a LAYOUTRETURN if list was initially empty */
1007         if (empty) {
1008                 spin_unlock(&ino->i_lock);
1009                 pnfs_put_layout_hdr(lo);
1010                 dprintk("NFS: %s no layout segments to return\n", __func__);
1011                 goto out;
1012         }
1013
1014         set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
1015         lo->plh_block_lgets++;
1016         spin_unlock(&ino->i_lock);
1017         pnfs_free_lseg_list(&tmp_list);
1018
1019         status = pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, true);
1020 out:
1021         dprintk("<-- %s status: %d\n", __func__, status);
1022         return status;
1023 }
1024 EXPORT_SYMBOL_GPL(_pnfs_return_layout);
1025
1026 int
1027 pnfs_commit_and_return_layout(struct inode *inode)
1028 {
1029         struct pnfs_layout_hdr *lo;
1030         int ret;
1031
1032         spin_lock(&inode->i_lock);
1033         lo = NFS_I(inode)->layout;
1034         if (lo == NULL) {
1035                 spin_unlock(&inode->i_lock);
1036                 return 0;
1037         }
1038         pnfs_get_layout_hdr(lo);
1039         /* Block new layoutgets and read/write to ds */
1040         lo->plh_block_lgets++;
1041         spin_unlock(&inode->i_lock);
1042         filemap_fdatawait(inode->i_mapping);
1043         ret = pnfs_layoutcommit_inode(inode, true);
1044         if (ret == 0)
1045                 ret = _pnfs_return_layout(inode);
1046         spin_lock(&inode->i_lock);
1047         lo->plh_block_lgets--;
1048         spin_unlock(&inode->i_lock);
1049         pnfs_put_layout_hdr(lo);
1050         return ret;
1051 }
1052
1053 bool pnfs_roc(struct inode *ino)
1054 {
1055         struct nfs_inode *nfsi = NFS_I(ino);
1056         struct nfs_open_context *ctx;
1057         struct nfs4_state *state;
1058         struct pnfs_layout_hdr *lo;
1059         struct pnfs_layout_segment *lseg, *tmp;
1060         nfs4_stateid stateid;
1061         LIST_HEAD(tmp_list);
1062         bool found = false, layoutreturn = false;
1063
1064         spin_lock(&ino->i_lock);
1065         lo = nfsi->layout;
1066         if (!lo || !test_and_clear_bit(NFS_LAYOUT_ROC, &lo->plh_flags) ||
1067             test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags))
1068                 goto out_noroc;
1069
1070         /* Don't return layout if we hold a delegation */
1071         if (nfs4_check_delegation(ino, FMODE_READ))
1072                 goto out_noroc;
1073
1074         list_for_each_entry(ctx, &nfsi->open_files, list) {
1075                 state = ctx->state;
1076                 /* Don't return layout if there is open file state */
1077                 if (state != NULL && state->state != 0)
1078                         goto out_noroc;
1079         }
1080
1081         pnfs_clear_retry_layoutget(lo);
1082         list_for_each_entry_safe(lseg, tmp, &lo->plh_segs, pls_list)
1083                 if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
1084                         mark_lseg_invalid(lseg, &tmp_list);
1085                         found = true;
1086                 }
1087         if (!found)
1088                 goto out_noroc;
1089         lo->plh_block_lgets++;
1090         pnfs_get_layout_hdr(lo); /* matched in pnfs_roc_release */
1091         spin_unlock(&ino->i_lock);
1092         pnfs_free_lseg_list(&tmp_list);
1093         pnfs_layoutcommit_inode(ino, true);
1094         return true;
1095
1096 out_noroc:
1097         if (lo) {
1098                 stateid = lo->plh_stateid;
1099                 layoutreturn =
1100                         test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,
1101                                            &lo->plh_flags);
1102                 if (layoutreturn) {
1103                         lo->plh_block_lgets++;
1104                         pnfs_get_layout_hdr(lo);
1105                 }
1106         }
1107         spin_unlock(&ino->i_lock);
1108         if (layoutreturn) {
1109                 pnfs_layoutcommit_inode(ino, true);
1110                 pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, true);
1111         }
1112         return false;
1113 }
1114
1115 void pnfs_roc_release(struct inode *ino)
1116 {
1117         struct pnfs_layout_hdr *lo;
1118
1119         spin_lock(&ino->i_lock);
1120         lo = NFS_I(ino)->layout;
1121         lo->plh_block_lgets--;
1122         if (atomic_dec_and_test(&lo->plh_refcount)) {
1123                 pnfs_detach_layout_hdr(lo);
1124                 spin_unlock(&ino->i_lock);
1125                 pnfs_free_layout_hdr(lo);
1126         } else
1127                 spin_unlock(&ino->i_lock);
1128 }
1129
1130 void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
1131 {
1132         struct pnfs_layout_hdr *lo;
1133
1134         spin_lock(&ino->i_lock);
1135         lo = NFS_I(ino)->layout;
1136         if (pnfs_seqid_is_newer(barrier, lo->plh_barrier))
1137                 lo->plh_barrier = barrier;
1138         spin_unlock(&ino->i_lock);
1139 }
1140
1141 bool pnfs_roc_drain(struct inode *ino, u32 *barrier, struct rpc_task *task)
1142 {
1143         struct nfs_inode *nfsi = NFS_I(ino);
1144         struct pnfs_layout_hdr *lo;
1145         struct pnfs_layout_segment *lseg;
1146         nfs4_stateid stateid;
1147         u32 current_seqid;
1148         bool found = false, layoutreturn = false;
1149
1150         spin_lock(&ino->i_lock);
1151         list_for_each_entry(lseg, &nfsi->layout->plh_segs, pls_list)
1152                 if (test_bit(NFS_LSEG_ROC, &lseg->pls_flags)) {
1153                         rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
1154                         found = true;
1155                         goto out;
1156                 }
1157         lo = nfsi->layout;
1158         current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
1159
1160         /* Since close does not return a layout stateid for use as
1161          * a barrier, we choose the worst-case barrier.
1162          */
1163         *barrier = current_seqid + atomic_read(&lo->plh_outstanding);
1164 out:
1165         if (!found) {
1166                 stateid = lo->plh_stateid;
1167                 layoutreturn =
1168                         test_and_clear_bit(NFS_LAYOUT_RETURN_BEFORE_CLOSE,
1169                                            &lo->plh_flags);
1170                 if (layoutreturn) {
1171                         lo->plh_block_lgets++;
1172                         pnfs_get_layout_hdr(lo);
1173                 }
1174         }
1175         spin_unlock(&ino->i_lock);
1176         if (layoutreturn) {
1177                 rpc_sleep_on(&NFS_SERVER(ino)->roc_rpcwaitq, task, NULL);
1178                 pnfs_send_layoutreturn(lo, stateid, IOMODE_ANY, false);
1179         }
1180         return found;
1181 }
1182
1183 /*
1184  * Compare two layout segments for sorting into layout cache.
1185  * We want to preferentially return RW over RO layouts, so ensure those
1186  * are seen first.
1187  */
1188 static s64
1189 pnfs_lseg_range_cmp(const struct pnfs_layout_range *l1,
1190            const struct pnfs_layout_range *l2)
1191 {
1192         s64 d;
1193
1194         /* high offset > low offset */
1195         d = l1->offset - l2->offset;
1196         if (d)
1197                 return d;
1198
1199         /* short length > long length */
1200         d = l2->length - l1->length;
1201         if (d)
1202                 return d;
1203
1204         /* read > read/write */
1205         return (int)(l1->iomode == IOMODE_READ) - (int)(l2->iomode == IOMODE_READ);
1206 }
1207
1208 static void
1209 pnfs_layout_insert_lseg(struct pnfs_layout_hdr *lo,
1210                    struct pnfs_layout_segment *lseg)
1211 {
1212         struct pnfs_layout_segment *lp;
1213
1214         dprintk("%s:Begin\n", __func__);
1215
1216         list_for_each_entry(lp, &lo->plh_segs, pls_list) {
1217                 if (pnfs_lseg_range_cmp(&lseg->pls_range, &lp->pls_range) > 0)
1218                         continue;
1219                 list_add_tail(&lseg->pls_list, &lp->pls_list);
1220                 dprintk("%s: inserted lseg %p "
1221                         "iomode %d offset %llu length %llu before "
1222                         "lp %p iomode %d offset %llu length %llu\n",
1223                         __func__, lseg, lseg->pls_range.iomode,
1224                         lseg->pls_range.offset, lseg->pls_range.length,
1225                         lp, lp->pls_range.iomode, lp->pls_range.offset,
1226                         lp->pls_range.length);
1227                 goto out;
1228         }
1229         list_add_tail(&lseg->pls_list, &lo->plh_segs);
1230         dprintk("%s: inserted lseg %p "
1231                 "iomode %d offset %llu length %llu at tail\n",
1232                 __func__, lseg, lseg->pls_range.iomode,
1233                 lseg->pls_range.offset, lseg->pls_range.length);
1234 out:
1235         pnfs_get_layout_hdr(lo);
1236
1237         dprintk("%s:Return\n", __func__);
1238 }
1239
1240 static struct pnfs_layout_hdr *
1241 alloc_init_layout_hdr(struct inode *ino,
1242                       struct nfs_open_context *ctx,
1243                       gfp_t gfp_flags)
1244 {
1245         struct pnfs_layout_hdr *lo;
1246
1247         lo = pnfs_alloc_layout_hdr(ino, gfp_flags);
1248         if (!lo)
1249                 return NULL;
1250         atomic_set(&lo->plh_refcount, 1);
1251         INIT_LIST_HEAD(&lo->plh_layouts);
1252         INIT_LIST_HEAD(&lo->plh_segs);
1253         INIT_LIST_HEAD(&lo->plh_bulk_destroy);
1254         lo->plh_inode = ino;
1255         lo->plh_lc_cred = get_rpccred(ctx->cred);
1256         return lo;
1257 }
1258
1259 static struct pnfs_layout_hdr *
1260 pnfs_find_alloc_layout(struct inode *ino,
1261                        struct nfs_open_context *ctx,
1262                        gfp_t gfp_flags)
1263 {
1264         struct nfs_inode *nfsi = NFS_I(ino);
1265         struct pnfs_layout_hdr *new = NULL;
1266
1267         dprintk("%s Begin ino=%p layout=%p\n", __func__, ino, nfsi->layout);
1268
1269         if (nfsi->layout != NULL)
1270                 goto out_existing;
1271         spin_unlock(&ino->i_lock);
1272         new = alloc_init_layout_hdr(ino, ctx, gfp_flags);
1273         spin_lock(&ino->i_lock);
1274
1275         if (likely(nfsi->layout == NULL)) {     /* Won the race? */
1276                 nfsi->layout = new;
1277                 return new;
1278         } else if (new != NULL)
1279                 pnfs_free_layout_hdr(new);
1280 out_existing:
1281         pnfs_get_layout_hdr(nfsi->layout);
1282         return nfsi->layout;
1283 }
1284
1285 /*
1286  * iomode matching rules:
1287  * iomode       lseg    match
1288  * -----        -----   -----
1289  * ANY          READ    true
1290  * ANY          RW      true
1291  * RW           READ    false
1292  * RW           RW      true
1293  * READ         READ    true
1294  * READ         RW      true
1295  */
1296 static bool
1297 pnfs_lseg_range_match(const struct pnfs_layout_range *ls_range,
1298                  const struct pnfs_layout_range *range)
1299 {
1300         struct pnfs_layout_range range1;
1301
1302         if ((range->iomode == IOMODE_RW &&
1303              ls_range->iomode != IOMODE_RW) ||
1304             !pnfs_lseg_range_intersecting(ls_range, range))
1305                 return 0;
1306
1307         /* range1 covers only the first byte in the range */
1308         range1 = *range;
1309         range1.length = 1;
1310         return pnfs_lseg_range_contained(ls_range, &range1);
1311 }
1312
1313 /*
1314  * lookup range in layout
1315  */
1316 static struct pnfs_layout_segment *
1317 pnfs_find_lseg(struct pnfs_layout_hdr *lo,
1318                 struct pnfs_layout_range *range)
1319 {
1320         struct pnfs_layout_segment *lseg, *ret = NULL;
1321
1322         dprintk("%s:Begin\n", __func__);
1323
1324         list_for_each_entry(lseg, &lo->plh_segs, pls_list) {
1325                 if (test_bit(NFS_LSEG_VALID, &lseg->pls_flags) &&
1326                     !test_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags) &&
1327                     pnfs_lseg_range_match(&lseg->pls_range, range)) {
1328                         ret = pnfs_get_lseg(lseg);
1329                         break;
1330                 }
1331                 if (lseg->pls_range.offset > range->offset)
1332                         break;
1333         }
1334
1335         dprintk("%s:Return lseg %p ref %d\n",
1336                 __func__, ret, ret ? atomic_read(&ret->pls_refcount) : 0);
1337         return ret;
1338 }
1339
1340 /*
1341  * Use mdsthreshold hints set at each OPEN to determine if I/O should go
1342  * to the MDS or over pNFS
1343  *
1344  * The nfs_inode read_io and write_io fields are cumulative counters reset
1345  * when there are no layout segments. Note that in pnfs_update_layout iomode
1346  * is set to IOMODE_READ for a READ request, and set to IOMODE_RW for a
1347  * WRITE request.
1348  *
1349  * A return of true means use MDS I/O.
1350  *
1351  * From rfc 5661:
1352  * If a file's size is smaller than the file size threshold, data accesses
1353  * SHOULD be sent to the metadata server.  If an I/O request has a length that
1354  * is below the I/O size threshold, the I/O SHOULD be sent to the metadata
1355  * server.  If both file size and I/O size are provided, the client SHOULD
1356  * reach or exceed  both thresholds before sending its read or write
1357  * requests to the data server.
1358  */
1359 static bool pnfs_within_mdsthreshold(struct nfs_open_context *ctx,
1360                                      struct inode *ino, int iomode)
1361 {
1362         struct nfs4_threshold *t = ctx->mdsthreshold;
1363         struct nfs_inode *nfsi = NFS_I(ino);
1364         loff_t fsize = i_size_read(ino);
1365         bool size = false, size_set = false, io = false, io_set = false, ret = false;
1366
1367         if (t == NULL)
1368                 return ret;
1369
1370         dprintk("%s bm=0x%x rd_sz=%llu wr_sz=%llu rd_io=%llu wr_io=%llu\n",
1371                 __func__, t->bm, t->rd_sz, t->wr_sz, t->rd_io_sz, t->wr_io_sz);
1372
1373         switch (iomode) {
1374         case IOMODE_READ:
1375                 if (t->bm & THRESHOLD_RD) {
1376                         dprintk("%s fsize %llu\n", __func__, fsize);
1377                         size_set = true;
1378                         if (fsize < t->rd_sz)
1379                                 size = true;
1380                 }
1381                 if (t->bm & THRESHOLD_RD_IO) {
1382                         dprintk("%s nfsi->read_io %llu\n", __func__,
1383                                 nfsi->read_io);
1384                         io_set = true;
1385                         if (nfsi->read_io < t->rd_io_sz)
1386                                 io = true;
1387                 }
1388                 break;
1389         case IOMODE_RW:
1390                 if (t->bm & THRESHOLD_WR) {
1391                         dprintk("%s fsize %llu\n", __func__, fsize);
1392                         size_set = true;
1393                         if (fsize < t->wr_sz)
1394                                 size = true;
1395                 }
1396                 if (t->bm & THRESHOLD_WR_IO) {
1397                         dprintk("%s nfsi->write_io %llu\n", __func__,
1398                                 nfsi->write_io);
1399                         io_set = true;
1400                         if (nfsi->write_io < t->wr_io_sz)
1401                                 io = true;
1402                 }
1403                 break;
1404         }
1405         if (size_set && io_set) {
1406                 if (size && io)
1407                         ret = true;
1408         } else if (size || io)
1409                 ret = true;
1410
1411         dprintk("<-- %s size %d io %d ret %d\n", __func__, size, io, ret);
1412         return ret;
1413 }
1414
1415 /* stop waiting if someone clears NFS_LAYOUT_RETRY_LAYOUTGET bit. */
1416 static int pnfs_layoutget_retry_bit_wait(struct wait_bit_key *key)
1417 {
1418         if (!test_bit(NFS_LAYOUT_RETRY_LAYOUTGET, key->flags))
1419                 return 1;
1420         return nfs_wait_bit_killable(key);
1421 }
1422
1423 static bool pnfs_prepare_to_retry_layoutget(struct pnfs_layout_hdr *lo)
1424 {
1425         /*
1426          * send layoutcommit as it can hold up layoutreturn due to lseg
1427          * reference
1428          */
1429         pnfs_layoutcommit_inode(lo->plh_inode, false);
1430         return !wait_on_bit_action(&lo->plh_flags, NFS_LAYOUT_RETURN,
1431                                    pnfs_layoutget_retry_bit_wait,
1432                                    TASK_UNINTERRUPTIBLE);
1433 }
1434
1435 static void pnfs_clear_first_layoutget(struct pnfs_layout_hdr *lo)
1436 {
1437         unsigned long *bitlock = &lo->plh_flags;
1438
1439         clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock);
1440         smp_mb__after_atomic();
1441         wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET);
1442 }
1443
1444 /*
1445  * Layout segment is retreived from the server if not cached.
1446  * The appropriate layout segment is referenced and returned to the caller.
1447  */
1448 struct pnfs_layout_segment *
1449 pnfs_update_layout(struct inode *ino,
1450                    struct nfs_open_context *ctx,
1451                    loff_t pos,
1452                    u64 count,
1453                    enum pnfs_iomode iomode,
1454                    gfp_t gfp_flags)
1455 {
1456         struct pnfs_layout_range arg = {
1457                 .iomode = iomode,
1458                 .offset = pos,
1459                 .length = count,
1460         };
1461         unsigned pg_offset;
1462         struct nfs_server *server = NFS_SERVER(ino);
1463         struct nfs_client *clp = server->nfs_client;
1464         struct pnfs_layout_hdr *lo;
1465         struct pnfs_layout_segment *lseg = NULL;
1466         bool first;
1467
1468         if (!pnfs_enabled_sb(NFS_SERVER(ino)))
1469                 goto out;
1470
1471         if (pnfs_within_mdsthreshold(ctx, ino, iomode))
1472                 goto out;
1473
1474 lookup_again:
1475         first = false;
1476         spin_lock(&ino->i_lock);
1477         lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags);
1478         if (lo == NULL) {
1479                 spin_unlock(&ino->i_lock);
1480                 goto out;
1481         }
1482
1483         /* Do we even need to bother with this? */
1484         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1485                 dprintk("%s matches recall, use MDS\n", __func__);
1486                 goto out_unlock;
1487         }
1488
1489         /* if LAYOUTGET already failed once we don't try again */
1490         if (pnfs_layout_io_test_failed(lo, iomode) &&
1491             !pnfs_should_retry_layoutget(lo))
1492                 goto out_unlock;
1493
1494         first = list_empty(&lo->plh_segs);
1495         if (first) {
1496                 /* The first layoutget for the file. Need to serialize per
1497                  * RFC 5661 Errata 3208.
1498                  */
1499                 if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET,
1500                                      &lo->plh_flags)) {
1501                         spin_unlock(&ino->i_lock);
1502                         wait_on_bit(&lo->plh_flags, NFS_LAYOUT_FIRST_LAYOUTGET,
1503                                     TASK_UNINTERRUPTIBLE);
1504                         pnfs_put_layout_hdr(lo);
1505                         goto lookup_again;
1506                 }
1507         } else {
1508                 /* Check to see if the layout for the given range
1509                  * already exists
1510                  */
1511                 lseg = pnfs_find_lseg(lo, &arg);
1512                 if (lseg)
1513                         goto out_unlock;
1514         }
1515
1516         /*
1517          * Because we free lsegs before sending LAYOUTRETURN, we need to wait
1518          * for LAYOUTRETURN even if first is true.
1519          */
1520         if (!lseg && pnfs_should_retry_layoutget(lo) &&
1521             test_bit(NFS_LAYOUT_RETURN, &lo->plh_flags)) {
1522                 spin_unlock(&ino->i_lock);
1523                 dprintk("%s wait for layoutreturn\n", __func__);
1524                 if (pnfs_prepare_to_retry_layoutget(lo)) {
1525                         if (first)
1526                                 pnfs_clear_first_layoutget(lo);
1527                         pnfs_put_layout_hdr(lo);
1528                         dprintk("%s retrying\n", __func__);
1529                         goto lookup_again;
1530                 }
1531                 goto out_put_layout_hdr;
1532         }
1533
1534         if (pnfs_layoutgets_blocked(lo, &arg, 0))
1535                 goto out_unlock;
1536         atomic_inc(&lo->plh_outstanding);
1537         spin_unlock(&ino->i_lock);
1538
1539         if (list_empty(&lo->plh_layouts)) {
1540                 /* The lo must be on the clp list if there is any
1541                  * chance of a CB_LAYOUTRECALL(FILE) coming in.
1542                  */
1543                 spin_lock(&clp->cl_lock);
1544                 if (list_empty(&lo->plh_layouts))
1545                         list_add_tail(&lo->plh_layouts, &server->layouts);
1546                 spin_unlock(&clp->cl_lock);
1547         }
1548
1549         pg_offset = arg.offset & ~PAGE_CACHE_MASK;
1550         if (pg_offset) {
1551                 arg.offset -= pg_offset;
1552                 arg.length += pg_offset;
1553         }
1554         if (arg.length != NFS4_MAX_UINT64)
1555                 arg.length = PAGE_CACHE_ALIGN(arg.length);
1556
1557         lseg = send_layoutget(lo, ctx, &arg, gfp_flags);
1558         pnfs_clear_retry_layoutget(lo);
1559         atomic_dec(&lo->plh_outstanding);
1560 out_put_layout_hdr:
1561         if (first)
1562                 pnfs_clear_first_layoutget(lo);
1563         pnfs_put_layout_hdr(lo);
1564 out:
1565         dprintk("%s: inode %s/%llu pNFS layout segment %s for "
1566                         "(%s, offset: %llu, length: %llu)\n",
1567                         __func__, ino->i_sb->s_id,
1568                         (unsigned long long)NFS_FILEID(ino),
1569                         lseg == NULL ? "not found" : "found",
1570                         iomode==IOMODE_RW ?  "read/write" : "read-only",
1571                         (unsigned long long)pos,
1572                         (unsigned long long)count);
1573         return lseg;
1574 out_unlock:
1575         spin_unlock(&ino->i_lock);
1576         goto out_put_layout_hdr;
1577 }
1578 EXPORT_SYMBOL_GPL(pnfs_update_layout);
1579
1580 struct pnfs_layout_segment *
1581 pnfs_layout_process(struct nfs4_layoutget *lgp)
1582 {
1583         struct pnfs_layout_hdr *lo = NFS_I(lgp->args.inode)->layout;
1584         struct nfs4_layoutget_res *res = &lgp->res;
1585         struct pnfs_layout_segment *lseg;
1586         struct inode *ino = lo->plh_inode;
1587         LIST_HEAD(free_me);
1588         int status = 0;
1589
1590         /* Inject layout blob into I/O device driver */
1591         lseg = NFS_SERVER(ino)->pnfs_curr_ld->alloc_lseg(lo, res, lgp->gfp_flags);
1592         if (!lseg || IS_ERR(lseg)) {
1593                 if (!lseg)
1594                         status = -ENOMEM;
1595                 else
1596                         status = PTR_ERR(lseg);
1597                 dprintk("%s: Could not allocate layout: error %d\n",
1598                        __func__, status);
1599                 goto out;
1600         }
1601
1602         init_lseg(lo, lseg);
1603         lseg->pls_range = res->range;
1604
1605         spin_lock(&ino->i_lock);
1606         if (test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
1607                 dprintk("%s forget reply due to recall\n", __func__);
1608                 goto out_forget_reply;
1609         }
1610
1611         if (pnfs_layoutgets_blocked(lo, &lgp->args.range, 1)) {
1612                 dprintk("%s forget reply due to state\n", __func__);
1613                 goto out_forget_reply;
1614         }
1615
1616         if (nfs4_stateid_match_other(&lo->plh_stateid, &res->stateid)) {
1617                 /* existing state ID, make sure the sequence number matches. */
1618                 if (pnfs_layout_stateid_blocked(lo, &res->stateid)) {
1619                         dprintk("%s forget reply due to sequence\n", __func__);
1620                         goto out_forget_reply;
1621                 }
1622                 pnfs_set_layout_stateid(lo, &res->stateid, false);
1623         } else {
1624                 /*
1625                  * We got an entirely new state ID.  Mark all segments for the
1626                  * inode invalid, and don't bother validating the stateid
1627                  * sequence number.
1628                  */
1629                 pnfs_mark_matching_lsegs_invalid(lo, &free_me, NULL);
1630
1631                 nfs4_stateid_copy(&lo->plh_stateid, &res->stateid);
1632                 lo->plh_barrier = be32_to_cpu(res->stateid.seqid);
1633         }
1634
1635         clear_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
1636
1637         pnfs_get_lseg(lseg);
1638         pnfs_layout_insert_lseg(lo, lseg);
1639
1640         if (res->return_on_close) {
1641                 set_bit(NFS_LSEG_ROC, &lseg->pls_flags);
1642                 set_bit(NFS_LAYOUT_ROC, &lo->plh_flags);
1643         }
1644
1645         spin_unlock(&ino->i_lock);
1646         pnfs_free_lseg_list(&free_me);
1647         return lseg;
1648 out:
1649         return ERR_PTR(status);
1650
1651 out_forget_reply:
1652         spin_unlock(&ino->i_lock);
1653         lseg->pls_layout = lo;
1654         NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
1655         goto out;
1656 }
1657
1658 static void
1659 pnfs_mark_matching_lsegs_return(struct pnfs_layout_hdr *lo,
1660                                 struct list_head *tmp_list,
1661                                 struct pnfs_layout_range *return_range)
1662 {
1663         struct pnfs_layout_segment *lseg, *next;
1664
1665         dprintk("%s:Begin lo %p\n", __func__, lo);
1666
1667         if (list_empty(&lo->plh_segs))
1668                 return;
1669
1670         list_for_each_entry_safe(lseg, next, &lo->plh_segs, pls_list)
1671                 if (should_free_lseg(&lseg->pls_range, return_range)) {
1672                         dprintk("%s: marking lseg %p iomode %d "
1673                                 "offset %llu length %llu\n", __func__,
1674                                 lseg, lseg->pls_range.iomode,
1675                                 lseg->pls_range.offset,
1676                                 lseg->pls_range.length);
1677                         set_bit(NFS_LSEG_LAYOUTRETURN, &lseg->pls_flags);
1678                         mark_lseg_invalid(lseg, tmp_list);
1679                 }
1680 }
1681
1682 void pnfs_error_mark_layout_for_return(struct inode *inode,
1683                                        struct pnfs_layout_segment *lseg)
1684 {
1685         struct pnfs_layout_hdr *lo = NFS_I(inode)->layout;
1686         int iomode = pnfs_iomode_to_fail_bit(lseg->pls_range.iomode);
1687         struct pnfs_layout_range range = {
1688                 .iomode = lseg->pls_range.iomode,
1689                 .offset = 0,
1690                 .length = NFS4_MAX_UINT64,
1691         };
1692         LIST_HEAD(free_me);
1693
1694         spin_lock(&inode->i_lock);
1695         /* set failure bit so that pnfs path will be retried later */
1696         pnfs_layout_set_fail_bit(lo, iomode);
1697         set_bit(NFS_LAYOUT_RETURN, &lo->plh_flags);
1698         if (lo->plh_return_iomode == 0)
1699                 lo->plh_return_iomode = range.iomode;
1700         else if (lo->plh_return_iomode != range.iomode)
1701                 lo->plh_return_iomode = IOMODE_ANY;
1702         /*
1703          * mark all matching lsegs so that we are sure to have no live
1704          * segments at hand when sending layoutreturn. See pnfs_put_lseg()
1705          * for how it works.
1706          */
1707         pnfs_mark_matching_lsegs_return(lo, &free_me, &range);
1708         spin_unlock(&inode->i_lock);
1709         pnfs_free_lseg_list(&free_me);
1710 }
1711 EXPORT_SYMBOL_GPL(pnfs_error_mark_layout_for_return);
1712
1713 void
1714 pnfs_generic_pg_init_read(struct nfs_pageio_descriptor *pgio, struct nfs_page *req)
1715 {
1716         u64 rd_size = req->wb_bytes;
1717
1718         if (pgio->pg_lseg == NULL) {
1719                 if (pgio->pg_dreq == NULL)
1720                         rd_size = i_size_read(pgio->pg_inode) - req_offset(req);
1721                 else
1722                         rd_size = nfs_dreq_bytes_left(pgio->pg_dreq);
1723
1724                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1725                                                    req->wb_context,
1726                                                    req_offset(req),
1727                                                    rd_size,
1728                                                    IOMODE_READ,
1729                                                    GFP_KERNEL);
1730         }
1731         /* If no lseg, fall back to read through mds */
1732         if (pgio->pg_lseg == NULL)
1733                 nfs_pageio_reset_read_mds(pgio);
1734
1735 }
1736 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_read);
1737
1738 void
1739 pnfs_generic_pg_init_write(struct nfs_pageio_descriptor *pgio,
1740                            struct nfs_page *req, u64 wb_size)
1741 {
1742         if (pgio->pg_lseg == NULL)
1743                 pgio->pg_lseg = pnfs_update_layout(pgio->pg_inode,
1744                                                    req->wb_context,
1745                                                    req_offset(req),
1746                                                    wb_size,
1747                                                    IOMODE_RW,
1748                                                    GFP_NOFS);
1749         /* If no lseg, fall back to write through mds */
1750         if (pgio->pg_lseg == NULL)
1751                 nfs_pageio_reset_write_mds(pgio);
1752 }
1753 EXPORT_SYMBOL_GPL(pnfs_generic_pg_init_write);
1754
1755 void
1756 pnfs_generic_pg_cleanup(struct nfs_pageio_descriptor *desc)
1757 {
1758         if (desc->pg_lseg) {
1759                 pnfs_put_lseg(desc->pg_lseg);
1760                 desc->pg_lseg = NULL;
1761         }
1762 }
1763 EXPORT_SYMBOL_GPL(pnfs_generic_pg_cleanup);
1764
1765 /*
1766  * Return 0 if @req cannot be coalesced into @pgio, otherwise return the number
1767  * of bytes (maximum @req->wb_bytes) that can be coalesced.
1768  */
1769 size_t
1770 pnfs_generic_pg_test(struct nfs_pageio_descriptor *pgio,
1771                      struct nfs_page *prev, struct nfs_page *req)
1772 {
1773         unsigned int size;
1774         u64 seg_end, req_start, seg_left;
1775
1776         size = nfs_generic_pg_test(pgio, prev, req);
1777         if (!size)
1778                 return 0;
1779
1780         /*
1781          * 'size' contains the number of bytes left in the current page (up
1782          * to the original size asked for in @req->wb_bytes).
1783          *
1784          * Calculate how many bytes are left in the layout segment
1785          * and if there are less bytes than 'size', return that instead.
1786          *
1787          * Please also note that 'end_offset' is actually the offset of the
1788          * first byte that lies outside the pnfs_layout_range. FIXME?
1789          *
1790          */
1791         if (pgio->pg_lseg) {
1792                 seg_end = end_offset(pgio->pg_lseg->pls_range.offset,
1793                                      pgio->pg_lseg->pls_range.length);
1794                 req_start = req_offset(req);
1795                 WARN_ON_ONCE(req_start >= seg_end);
1796                 /* start of request is past the last byte of this segment */
1797                 if (req_start >= seg_end) {
1798                         /* reference the new lseg */
1799                         if (pgio->pg_ops->pg_cleanup)
1800                                 pgio->pg_ops->pg_cleanup(pgio);
1801                         if (pgio->pg_ops->pg_init)
1802                                 pgio->pg_ops->pg_init(pgio, req);
1803                         return 0;
1804                 }
1805
1806                 /* adjust 'size' iff there are fewer bytes left in the
1807                  * segment than what nfs_generic_pg_test returned */
1808                 seg_left = seg_end - req_start;
1809                 if (seg_left < size)
1810                         size = (unsigned int)seg_left;
1811         }
1812
1813         return size;
1814 }
1815 EXPORT_SYMBOL_GPL(pnfs_generic_pg_test);
1816
1817 int pnfs_write_done_resend_to_mds(struct nfs_pgio_header *hdr)
1818 {
1819         struct nfs_pageio_descriptor pgio;
1820
1821         /* Resend all requests through the MDS */
1822         nfs_pageio_init_write(&pgio, hdr->inode, FLUSH_STABLE, true,
1823                               hdr->completion_ops);
1824         set_bit(NFS_CONTEXT_RESEND_WRITES, &hdr->args.context->flags);
1825         return nfs_pageio_resend(&pgio, hdr);
1826 }
1827 EXPORT_SYMBOL_GPL(pnfs_write_done_resend_to_mds);
1828
1829 static void pnfs_ld_handle_write_error(struct nfs_pgio_header *hdr)
1830 {
1831
1832         dprintk("pnfs write error = %d\n", hdr->pnfs_error);
1833         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1834             PNFS_LAYOUTRET_ON_ERROR) {
1835                 pnfs_return_layout(hdr->inode);
1836         }
1837         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1838                 hdr->task.tk_status = pnfs_write_done_resend_to_mds(hdr);
1839 }
1840
1841 /*
1842  * Called by non rpc-based layout drivers
1843  */
1844 void pnfs_ld_write_done(struct nfs_pgio_header *hdr)
1845 {
1846         trace_nfs4_pnfs_write(hdr, hdr->pnfs_error);
1847         if (!hdr->pnfs_error) {
1848                 pnfs_set_layoutcommit(hdr->inode, hdr->lseg,
1849                                 hdr->mds_offset + hdr->res.count);
1850                 hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
1851         } else
1852                 pnfs_ld_handle_write_error(hdr);
1853         hdr->mds_ops->rpc_release(hdr);
1854 }
1855 EXPORT_SYMBOL_GPL(pnfs_ld_write_done);
1856
1857 static void
1858 pnfs_write_through_mds(struct nfs_pageio_descriptor *desc,
1859                 struct nfs_pgio_header *hdr)
1860 {
1861         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1862
1863         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1864                 list_splice_tail_init(&hdr->pages, &mirror->pg_list);
1865                 nfs_pageio_reset_write_mds(desc);
1866                 mirror->pg_recoalesce = 1;
1867         }
1868         nfs_pgio_data_destroy(hdr);
1869         hdr->release(hdr);
1870 }
1871
1872 static enum pnfs_try_status
1873 pnfs_try_to_write_data(struct nfs_pgio_header *hdr,
1874                         const struct rpc_call_ops *call_ops,
1875                         struct pnfs_layout_segment *lseg,
1876                         int how)
1877 {
1878         struct inode *inode = hdr->inode;
1879         enum pnfs_try_status trypnfs;
1880         struct nfs_server *nfss = NFS_SERVER(inode);
1881
1882         hdr->mds_ops = call_ops;
1883
1884         dprintk("%s: Writing ino:%lu %u@%llu (how %d)\n", __func__,
1885                 inode->i_ino, hdr->args.count, hdr->args.offset, how);
1886         trypnfs = nfss->pnfs_curr_ld->write_pagelist(hdr, how);
1887         if (trypnfs != PNFS_NOT_ATTEMPTED)
1888                 nfs_inc_stats(inode, NFSIOS_PNFS_WRITE);
1889         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
1890         return trypnfs;
1891 }
1892
1893 static void
1894 pnfs_do_write(struct nfs_pageio_descriptor *desc,
1895               struct nfs_pgio_header *hdr, int how)
1896 {
1897         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
1898         struct pnfs_layout_segment *lseg = desc->pg_lseg;
1899         enum pnfs_try_status trypnfs;
1900
1901         trypnfs = pnfs_try_to_write_data(hdr, call_ops, lseg, how);
1902         if (trypnfs == PNFS_NOT_ATTEMPTED)
1903                 pnfs_write_through_mds(desc, hdr);
1904 }
1905
1906 static void pnfs_writehdr_free(struct nfs_pgio_header *hdr)
1907 {
1908         pnfs_put_lseg(hdr->lseg);
1909         nfs_pgio_header_free(hdr);
1910 }
1911
1912 int
1913 pnfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1914 {
1915         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1916
1917         struct nfs_pgio_header *hdr;
1918         int ret;
1919
1920         hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
1921         if (!hdr) {
1922                 desc->pg_completion_ops->error_cleanup(&mirror->pg_list);
1923                 return -ENOMEM;
1924         }
1925         nfs_pgheader_init(desc, hdr, pnfs_writehdr_free);
1926
1927         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
1928         ret = nfs_generic_pgio(desc, hdr);
1929         if (!ret)
1930                 pnfs_do_write(desc, hdr, desc->pg_ioflags);
1931
1932         return ret;
1933 }
1934 EXPORT_SYMBOL_GPL(pnfs_generic_pg_writepages);
1935
1936 int pnfs_read_done_resend_to_mds(struct nfs_pgio_header *hdr)
1937 {
1938         struct nfs_pageio_descriptor pgio;
1939
1940         /* Resend all requests through the MDS */
1941         nfs_pageio_init_read(&pgio, hdr->inode, true, hdr->completion_ops);
1942         return nfs_pageio_resend(&pgio, hdr);
1943 }
1944 EXPORT_SYMBOL_GPL(pnfs_read_done_resend_to_mds);
1945
1946 static void pnfs_ld_handle_read_error(struct nfs_pgio_header *hdr)
1947 {
1948         dprintk("pnfs read error = %d\n", hdr->pnfs_error);
1949         if (NFS_SERVER(hdr->inode)->pnfs_curr_ld->flags &
1950             PNFS_LAYOUTRET_ON_ERROR) {
1951                 pnfs_return_layout(hdr->inode);
1952         }
1953         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags))
1954                 hdr->task.tk_status = pnfs_read_done_resend_to_mds(hdr);
1955 }
1956
1957 /*
1958  * Called by non rpc-based layout drivers
1959  */
1960 void pnfs_ld_read_done(struct nfs_pgio_header *hdr)
1961 {
1962         trace_nfs4_pnfs_read(hdr, hdr->pnfs_error);
1963         if (likely(!hdr->pnfs_error)) {
1964                 __nfs4_read_done_cb(hdr);
1965                 hdr->mds_ops->rpc_call_done(&hdr->task, hdr);
1966         } else
1967                 pnfs_ld_handle_read_error(hdr);
1968         hdr->mds_ops->rpc_release(hdr);
1969 }
1970 EXPORT_SYMBOL_GPL(pnfs_ld_read_done);
1971
1972 static void
1973 pnfs_read_through_mds(struct nfs_pageio_descriptor *desc,
1974                 struct nfs_pgio_header *hdr)
1975 {
1976         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1977
1978         if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) {
1979                 list_splice_tail_init(&hdr->pages, &mirror->pg_list);
1980                 nfs_pageio_reset_read_mds(desc);
1981                 mirror->pg_recoalesce = 1;
1982         }
1983         nfs_pgio_data_destroy(hdr);
1984         hdr->release(hdr);
1985 }
1986
1987 /*
1988  * Call the appropriate parallel I/O subsystem read function.
1989  */
1990 static enum pnfs_try_status
1991 pnfs_try_to_read_data(struct nfs_pgio_header *hdr,
1992                        const struct rpc_call_ops *call_ops,
1993                        struct pnfs_layout_segment *lseg)
1994 {
1995         struct inode *inode = hdr->inode;
1996         struct nfs_server *nfss = NFS_SERVER(inode);
1997         enum pnfs_try_status trypnfs;
1998
1999         hdr->mds_ops = call_ops;
2000
2001         dprintk("%s: Reading ino:%lu %u@%llu\n",
2002                 __func__, inode->i_ino, hdr->args.count, hdr->args.offset);
2003
2004         trypnfs = nfss->pnfs_curr_ld->read_pagelist(hdr);
2005         if (trypnfs != PNFS_NOT_ATTEMPTED)
2006                 nfs_inc_stats(inode, NFSIOS_PNFS_READ);
2007         dprintk("%s End (trypnfs:%d)\n", __func__, trypnfs);
2008         return trypnfs;
2009 }
2010
2011 /* Resend all requests through pnfs. */
2012 int pnfs_read_resend_pnfs(struct nfs_pgio_header *hdr)
2013 {
2014         struct nfs_pageio_descriptor pgio;
2015
2016         nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops);
2017         return nfs_pageio_resend(&pgio, hdr);
2018 }
2019 EXPORT_SYMBOL_GPL(pnfs_read_resend_pnfs);
2020
2021 static void
2022 pnfs_do_read(struct nfs_pageio_descriptor *desc, struct nfs_pgio_header *hdr)
2023 {
2024         const struct rpc_call_ops *call_ops = desc->pg_rpc_callops;
2025         struct pnfs_layout_segment *lseg = desc->pg_lseg;
2026         enum pnfs_try_status trypnfs;
2027         int err = 0;
2028
2029         trypnfs = pnfs_try_to_read_data(hdr, call_ops, lseg);
2030         if (trypnfs == PNFS_TRY_AGAIN)
2031                 err = pnfs_read_resend_pnfs(hdr);
2032         if (trypnfs == PNFS_NOT_ATTEMPTED || err)
2033                 pnfs_read_through_mds(desc, hdr);
2034 }
2035
2036 static void pnfs_readhdr_free(struct nfs_pgio_header *hdr)
2037 {
2038         pnfs_put_lseg(hdr->lseg);
2039         nfs_pgio_header_free(hdr);
2040 }
2041
2042 int
2043 pnfs_generic_pg_readpages(struct nfs_pageio_descriptor *desc)
2044 {
2045         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
2046
2047         struct nfs_pgio_header *hdr;
2048         int ret;
2049
2050         hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
2051         if (!hdr) {
2052                 desc->pg_completion_ops->error_cleanup(&mirror->pg_list);
2053                 return -ENOMEM;
2054         }
2055         nfs_pgheader_init(desc, hdr, pnfs_readhdr_free);
2056         hdr->lseg = pnfs_get_lseg(desc->pg_lseg);
2057         ret = nfs_generic_pgio(desc, hdr);
2058         if (!ret)
2059                 pnfs_do_read(desc, hdr);
2060         return ret;
2061 }
2062 EXPORT_SYMBOL_GPL(pnfs_generic_pg_readpages);
2063
2064 static void pnfs_clear_layoutcommitting(struct inode *inode)
2065 {
2066         unsigned long *bitlock = &NFS_I(inode)->flags;
2067
2068         clear_bit_unlock(NFS_INO_LAYOUTCOMMITTING, bitlock);
2069         smp_mb__after_atomic();
2070         wake_up_bit(bitlock, NFS_INO_LAYOUTCOMMITTING);
2071 }
2072
2073 /*
2074  * There can be multiple RW segments.
2075  */
2076 static void pnfs_list_write_lseg(struct inode *inode, struct list_head *listp)
2077 {
2078         struct pnfs_layout_segment *lseg;
2079
2080         list_for_each_entry(lseg, &NFS_I(inode)->layout->plh_segs, pls_list) {
2081                 if (lseg->pls_range.iomode == IOMODE_RW &&
2082                     test_and_clear_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags))
2083                         list_add(&lseg->pls_lc_list, listp);
2084         }
2085 }
2086
2087 static void pnfs_list_write_lseg_done(struct inode *inode, struct list_head *listp)
2088 {
2089         struct pnfs_layout_segment *lseg, *tmp;
2090
2091         /* Matched by references in pnfs_set_layoutcommit */
2092         list_for_each_entry_safe(lseg, tmp, listp, pls_lc_list) {
2093                 list_del_init(&lseg->pls_lc_list);
2094                 pnfs_put_lseg(lseg);
2095         }
2096
2097         pnfs_clear_layoutcommitting(inode);
2098 }
2099
2100 void pnfs_set_lo_fail(struct pnfs_layout_segment *lseg)
2101 {
2102         pnfs_layout_io_set_failed(lseg->pls_layout, lseg->pls_range.iomode);
2103 }
2104 EXPORT_SYMBOL_GPL(pnfs_set_lo_fail);
2105
2106 void
2107 pnfs_set_layoutcommit(struct inode *inode, struct pnfs_layout_segment *lseg,
2108                 loff_t end_pos)
2109 {
2110         struct nfs_inode *nfsi = NFS_I(inode);
2111         bool mark_as_dirty = false;
2112
2113         spin_lock(&inode->i_lock);
2114         if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
2115                 nfsi->layout->plh_lwb = end_pos;
2116                 mark_as_dirty = true;
2117                 dprintk("%s: Set layoutcommit for inode %lu ",
2118                         __func__, inode->i_ino);
2119         } else if (end_pos > nfsi->layout->plh_lwb)
2120                 nfsi->layout->plh_lwb = end_pos;
2121         if (!test_and_set_bit(NFS_LSEG_LAYOUTCOMMIT, &lseg->pls_flags)) {
2122                 /* references matched in nfs4_layoutcommit_release */
2123                 pnfs_get_lseg(lseg);
2124         }
2125         spin_unlock(&inode->i_lock);
2126         dprintk("%s: lseg %p end_pos %llu\n",
2127                 __func__, lseg, nfsi->layout->plh_lwb);
2128
2129         /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
2130          * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
2131         if (mark_as_dirty)
2132                 mark_inode_dirty_sync(inode);
2133 }
2134 EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);
2135
2136 void pnfs_cleanup_layoutcommit(struct nfs4_layoutcommit_data *data)
2137 {
2138         struct nfs_server *nfss = NFS_SERVER(data->args.inode);
2139
2140         if (nfss->pnfs_curr_ld->cleanup_layoutcommit)
2141                 nfss->pnfs_curr_ld->cleanup_layoutcommit(data);
2142         pnfs_list_write_lseg_done(data->args.inode, &data->lseg_list);
2143 }
2144
2145 /*
2146  * For the LAYOUT4_NFSV4_1_FILES layout type, NFS_DATA_SYNC WRITEs and
2147  * NFS_UNSTABLE WRITEs with a COMMIT to data servers must store enough
2148  * data to disk to allow the server to recover the data if it crashes.
2149  * LAYOUTCOMMIT is only needed when the NFL4_UFLG_COMMIT_THRU_MDS flag
2150  * is off, and a COMMIT is sent to a data server, or
2151  * if WRITEs to a data server return NFS_DATA_SYNC.
2152  */
2153 int
2154 pnfs_layoutcommit_inode(struct inode *inode, bool sync)
2155 {
2156         struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
2157         struct nfs4_layoutcommit_data *data;
2158         struct nfs_inode *nfsi = NFS_I(inode);
2159         loff_t end_pos;
2160         int status;
2161
2162         if (!pnfs_layoutcommit_outstanding(inode))
2163                 return 0;
2164
2165         dprintk("--> %s inode %lu\n", __func__, inode->i_ino);
2166
2167         status = -EAGAIN;
2168         if (test_and_set_bit(NFS_INO_LAYOUTCOMMITTING, &nfsi->flags)) {
2169                 if (!sync)
2170                         goto out;
2171                 status = wait_on_bit_lock_action(&nfsi->flags,
2172                                 NFS_INO_LAYOUTCOMMITTING,
2173                                 nfs_wait_bit_killable,
2174                                 TASK_KILLABLE);
2175                 if (status)
2176                         goto out;
2177         }
2178
2179         status = -ENOMEM;
2180         /* Note kzalloc ensures data->res.seq_res.sr_slot == NULL */
2181         data = kzalloc(sizeof(*data), GFP_NOFS);
2182         if (!data)
2183                 goto clear_layoutcommitting;
2184
2185         status = 0;
2186         spin_lock(&inode->i_lock);
2187         if (!test_and_clear_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags))
2188                 goto out_unlock;
2189
2190         INIT_LIST_HEAD(&data->lseg_list);
2191         pnfs_list_write_lseg(inode, &data->lseg_list);
2192
2193         end_pos = nfsi->layout->plh_lwb;
2194
2195         nfs4_stateid_copy(&data->args.stateid, &nfsi->layout->plh_stateid);
2196         spin_unlock(&inode->i_lock);
2197
2198         data->args.inode = inode;
2199         data->cred = get_rpccred(nfsi->layout->plh_lc_cred);
2200         nfs_fattr_init(&data->fattr);
2201         data->args.bitmask = NFS_SERVER(inode)->cache_consistency_bitmask;
2202         data->res.fattr = &data->fattr;
2203         data->args.lastbytewritten = end_pos - 1;
2204         data->res.server = NFS_SERVER(inode);
2205
2206         if (ld->prepare_layoutcommit) {
2207                 status = ld->prepare_layoutcommit(&data->args);
2208                 if (status) {
2209                         spin_lock(&inode->i_lock);
2210                         set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags);
2211                         if (end_pos > nfsi->layout->plh_lwb)
2212                                 nfsi->layout->plh_lwb = end_pos;
2213                         spin_unlock(&inode->i_lock);
2214                         put_rpccred(data->cred);
2215                         goto clear_layoutcommitting;
2216                 }
2217         }
2218
2219
2220         status = nfs4_proc_layoutcommit(data, sync);
2221 out:
2222         if (status)
2223                 mark_inode_dirty_sync(inode);
2224         dprintk("<-- %s status %d\n", __func__, status);
2225         return status;
2226 out_unlock:
2227         spin_unlock(&inode->i_lock);
2228         kfree(data);
2229 clear_layoutcommitting:
2230         pnfs_clear_layoutcommitting(inode);
2231         goto out;
2232 }
2233 EXPORT_SYMBOL_GPL(pnfs_layoutcommit_inode);
2234
2235 int
2236 pnfs_generic_sync(struct inode *inode, bool datasync)
2237 {
2238         return pnfs_layoutcommit_inode(inode, true);
2239 }
2240 EXPORT_SYMBOL_GPL(pnfs_generic_sync);
2241
2242 struct nfs4_threshold *pnfs_mdsthreshold_alloc(void)
2243 {
2244         struct nfs4_threshold *thp;
2245
2246         thp = kzalloc(sizeof(*thp), GFP_NOFS);
2247         if (!thp) {
2248                 dprintk("%s mdsthreshold allocation failed\n", __func__);
2249                 return NULL;
2250         }
2251         return thp;
2252 }