kernel/drivers/staging/lustre/lustre/llite/vvp_page.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * Implementation of cl_page for VVP layer.
  37  *
  38  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  39  *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_LLITE
  43
  44
  45 #include "../include/obd.h"
  46 #include "../include/lustre_lite.h"
  47
  48 #include "vvp_internal.h"
  49
  50 /*****************************************************************************
  51  *
  52  * Page operations.
  53  *
  54  */
  55
  56 static void vvp_page_fini_common(struct ccc_page *cp)
  57 {
  58         struct page *vmpage = cp->cpg_page;
  59
  60         LASSERT(vmpage != NULL);
  61         page_cache_release(vmpage);
  62 }
  63
  64 static void vvp_page_fini(const struct lu_env *env,
  65                           struct cl_page_slice *slice)
  66 {
  67         struct ccc_page *cp = cl2ccc_page(slice);
  68         struct page *vmpage  = cp->cpg_page;
  69
  70         /*
  71          * vmpage->private was already cleared when page was moved into
  72          * VPG_FREEING state.
  73          */
  74         LASSERT((struct cl_page *)vmpage->private != slice->cpl_page);
  75         vvp_page_fini_common(cp);
  76 }
  77
  78 static int vvp_page_own(const struct lu_env *env,
  79                         const struct cl_page_slice *slice, struct cl_io *io,
  80                         int nonblock)
  81 {
  82         struct ccc_page *vpg    = cl2ccc_page(slice);
  83         struct page      *vmpage = vpg->cpg_page;
  84
  85         LASSERT(vmpage != NULL);
  86         if (nonblock) {
  87                 if (!trylock_page(vmpage))
  88                         return -EAGAIN;
  89
  90                 if (unlikely(PageWriteback(vmpage))) {
  91                         unlock_page(vmpage);
  92                         return -EAGAIN;
  93                 }
  94
  95                 return 0;
  96         }
  97
  98         lock_page(vmpage);
  99         wait_on_page_writeback(vmpage);
 100         return 0;
 101 }
 102
 103 static void vvp_page_assume(const struct lu_env *env,
 104                             const struct cl_page_slice *slice,
 105                             struct cl_io *unused)
 106 {
 107         struct page *vmpage = cl2vm_page(slice);
 108
 109         LASSERT(vmpage != NULL);
 110         LASSERT(PageLocked(vmpage));
 111         wait_on_page_writeback(vmpage);
 112 }
 113
 114 static void vvp_page_unassume(const struct lu_env *env,
 115                               const struct cl_page_slice *slice,
 116                               struct cl_io *unused)
 117 {
 118         struct page *vmpage = cl2vm_page(slice);
 119
 120         LASSERT(vmpage != NULL);
 121         LASSERT(PageLocked(vmpage));
 122 }
 123
 124 static void vvp_page_disown(const struct lu_env *env,
 125                             const struct cl_page_slice *slice, struct cl_io *io)
 126 {
 127         struct page *vmpage = cl2vm_page(slice);
 128
 129         LASSERT(vmpage != NULL);
 130         LASSERT(PageLocked(vmpage));
 131
 132         unlock_page(cl2vm_page(slice));
 133 }
 134
 135 static void vvp_page_discard(const struct lu_env *env,
 136                              const struct cl_page_slice *slice,
 137                              struct cl_io *unused)
 138 {
 139         struct page        *vmpage  = cl2vm_page(slice);
 140         struct address_space *mapping;
 141         struct ccc_page      *cpg     = cl2ccc_page(slice);
 142
 143         LASSERT(vmpage != NULL);
 144         LASSERT(PageLocked(vmpage));
 145
 146         mapping = vmpage->mapping;
 147
 148         if (cpg->cpg_defer_uptodate && !cpg->cpg_ra_used)
 149                 ll_ra_stats_inc(mapping, RA_STAT_DISCARDED);
 150
 151         /*
 152          * truncate_complete_page() calls
 153          * a_ops->invalidatepage()->cl_page_delete()->vvp_page_delete().
 154          */
 155         truncate_complete_page(mapping, vmpage);
 156 }
 157
 158 static int vvp_page_unmap(const struct lu_env *env,
 159                           const struct cl_page_slice *slice,
 160                           struct cl_io *unused)
 161 {
 162         struct page *vmpage = cl2vm_page(slice);
 163         __u64       offset;
 164
 165         LASSERT(vmpage != NULL);
 166         LASSERT(PageLocked(vmpage));
 167
 168         offset = vmpage->index << PAGE_CACHE_SHIFT;
 169
 170         /*
 171          * XXX is it safe to call this with the page lock held?
 172          */
 173         ll_teardown_mmaps(vmpage->mapping, offset, offset + PAGE_CACHE_SIZE);
 174         return 0;
 175 }
 176
 177 static void vvp_page_delete(const struct lu_env *env,
 178                             const struct cl_page_slice *slice)
 179 {
 180         struct page       *vmpage = cl2vm_page(slice);
 181         struct inode     *inode  = vmpage->mapping->host;
 182         struct cl_object *obj    = slice->cpl_obj;
 183
 184         LASSERT(PageLocked(vmpage));
 185         LASSERT((struct cl_page *)vmpage->private == slice->cpl_page);
 186         LASSERT(inode == ccc_object_inode(obj));
 187
 188         vvp_write_complete(cl2ccc(obj), cl2ccc_page(slice));
 189         ClearPagePrivate(vmpage);
 190         vmpage->private = 0;
 191         /*
 192          * Reference from vmpage to cl_page is removed, but the reference back
 193          * is still here. It is removed later in vvp_page_fini().
 194          */
 195 }
 196
 197 static void vvp_page_export(const struct lu_env *env,
 198                             const struct cl_page_slice *slice,
 199                             int uptodate)
 200 {
 201         struct page *vmpage = cl2vm_page(slice);
 202
 203         LASSERT(vmpage != NULL);
 204         LASSERT(PageLocked(vmpage));
 205         if (uptodate)
 206                 SetPageUptodate(vmpage);
 207         else
 208                 ClearPageUptodate(vmpage);
 209 }
 210
 211 static int vvp_page_is_vmlocked(const struct lu_env *env,
 212                                 const struct cl_page_slice *slice)
 213 {
 214         return PageLocked(cl2vm_page(slice)) ? -EBUSY : -ENODATA;
 215 }
 216
 217 static int vvp_page_prep_read(const struct lu_env *env,
 218                               const struct cl_page_slice *slice,
 219                               struct cl_io *unused)
 220 {
 221         /* Skip the page already marked as PG_uptodate. */
 222         return PageUptodate(cl2vm_page(slice)) ? -EALREADY : 0;
 223 }
 224
 225 static int vvp_page_prep_write(const struct lu_env *env,
 226                                const struct cl_page_slice *slice,
 227                                struct cl_io *unused)
 228 {
 229         struct page *vmpage = cl2vm_page(slice);
 230
 231         LASSERT(PageLocked(vmpage));
 232         LASSERT(!PageDirty(vmpage));
 233
 234         set_page_writeback(vmpage);
 235         vvp_write_pending(cl2ccc(slice->cpl_obj), cl2ccc_page(slice));
 236
 237         return 0;
 238 }
 239
 240 /**
 241  * Handles page transfer errors at VM level.
 242  *
 243  * This takes inode as a separate argument, because inode on which error is to
 244  * be set can be different from \a vmpage inode in case of direct-io.
 245  */
 246 static void vvp_vmpage_error(struct inode *inode, struct page *vmpage, int ioret)
 247 {
 248         struct ccc_object *obj = cl_inode2ccc(inode);
 249
 250         if (ioret == 0) {
 251                 ClearPageError(vmpage);
 252                 obj->cob_discard_page_warned = 0;
 253         } else {
 254                 SetPageError(vmpage);
 255                 if (ioret == -ENOSPC)
 256                         set_bit(AS_ENOSPC, &inode->i_mapping->flags);
 257                 else
 258                         set_bit(AS_EIO, &inode->i_mapping->flags);
 259
 260                 if ((ioret == -ESHUTDOWN || ioret == -EINTR) &&
 261                      obj->cob_discard_page_warned == 0) {
 262                         obj->cob_discard_page_warned = 1;
 263                         ll_dirty_page_discard_warn(vmpage, ioret);
 264                 }
 265         }
 266 }
 267
 268 static void vvp_page_completion_read(const struct lu_env *env,
 269                                      const struct cl_page_slice *slice,
 270                                      int ioret)
 271 {
 272         struct ccc_page *cp     = cl2ccc_page(slice);
 273         struct page      *vmpage = cp->cpg_page;
 274         struct cl_page  *page   = cl_page_top(slice->cpl_page);
 275         struct inode    *inode  = ccc_object_inode(page->cp_obj);
 276
 277         LASSERT(PageLocked(vmpage));
 278         CL_PAGE_HEADER(D_PAGE, env, page, "completing READ with %d\n", ioret);
 279
 280         if (cp->cpg_defer_uptodate)
 281                 ll_ra_count_put(ll_i2sbi(inode), 1);
 282
 283         if (ioret == 0)  {
 284                 if (!cp->cpg_defer_uptodate)
 285                         cl_page_export(env, page, 1);
 286         } else
 287                 cp->cpg_defer_uptodate = 0;
 288
 289         if (page->cp_sync_io == NULL)
 290                 unlock_page(vmpage);
 291 }
 292
 293 static void vvp_page_completion_write(const struct lu_env *env,
 294                                       const struct cl_page_slice *slice,
 295                                       int ioret)
 296 {
 297         struct ccc_page *cp     = cl2ccc_page(slice);
 298         struct cl_page  *pg     = slice->cpl_page;
 299         struct page      *vmpage = cp->cpg_page;
 300
 301         LASSERT(ergo(pg->cp_sync_io != NULL, PageLocked(vmpage)));
 302         LASSERT(PageWriteback(vmpage));
 303
 304         CL_PAGE_HEADER(D_PAGE, env, pg, "completing WRITE with %d\n", ioret);
 305
 306         /*
 307          * TODO: Actually it makes sense to add the page into oap pending
 308          * list again and so that we don't need to take the page out from
 309          * SoM write pending list, if we just meet a recoverable error,
 310          * -ENOMEM, etc.
 311          * To implement this, we just need to return a non zero value in
 312          * ->cpo_completion method. The underlying transfer should be notified
 313          * and then re-add the page into pending transfer queue.  -jay
 314          */
 315
 316         cp->cpg_write_queued = 0;
 317         vvp_write_complete(cl2ccc(slice->cpl_obj), cp);
 318
 319         /*
 320          * Only mark the page error only when it's an async write because
 321          * applications won't wait for IO to finish.
 322          */
 323         if (pg->cp_sync_io == NULL)
 324                 vvp_vmpage_error(ccc_object_inode(pg->cp_obj), vmpage, ioret);
 325
 326         end_page_writeback(vmpage);
 327 }
 328
 329 /**
 330  * Implements cl_page_operations::cpo_make_ready() method.
 331  *
 332  * This is called to yank a page from the transfer cache and to send it out as
 333  * a part of transfer. This function try-locks the page. If try-lock failed,
 334  * page is owned by some concurrent IO, and should be skipped (this is bad,
 335  * but hopefully rare situation, as it usually results in transfer being
 336  * shorter than possible).
 337  *
 338  * \retval 0      success, page can be placed into transfer
 339  *
 340  * \retval -EAGAIN page is either used by concurrent IO has been
 341  * truncated. Skip it.
 342  */
 343 static int vvp_page_make_ready(const struct lu_env *env,
 344                                const struct cl_page_slice *slice)
 345 {
 346         struct page *vmpage = cl2vm_page(slice);
 347         struct cl_page *pg = slice->cpl_page;
 348         int result = 0;
 349
 350         lock_page(vmpage);
 351         if (clear_page_dirty_for_io(vmpage)) {
 352                 LASSERT(pg->cp_state == CPS_CACHED);
 353                 /* This actually clears the dirty bit in the radix
 354                  * tree. */
 355                 set_page_writeback(vmpage);
 356                 vvp_write_pending(cl2ccc(slice->cpl_obj),
 357                                 cl2ccc_page(slice));
 358                 CL_PAGE_HEADER(D_PAGE, env, pg, "readied\n");
 359         } else if (pg->cp_state == CPS_PAGEOUT) {
 360                 /* is it possible for osc_flush_async_page() to already
 361                  * make it ready? */
 362                 result = -EALREADY;
 363         } else {
 364                 CL_PAGE_DEBUG(D_ERROR, env, pg, "Unexpecting page state %d.\n",
 365                               pg->cp_state);
 366                 LBUG();
 367         }
 368         unlock_page(vmpage);
 369         return result;
 370 }
 371
 372 static int vvp_page_print(const struct lu_env *env,
 373                           const struct cl_page_slice *slice,
 374                           void *cookie, lu_printer_t printer)
 375 {
 376         struct ccc_page *vp = cl2ccc_page(slice);
 377         struct page      *vmpage = vp->cpg_page;
 378
 379         (*printer)(env, cookie, LUSTRE_VVP_NAME "-page@%p(%d:%d:%d) vm@%p ",
 380                    vp, vp->cpg_defer_uptodate, vp->cpg_ra_used,
 381                    vp->cpg_write_queued, vmpage);
 382         if (vmpage != NULL) {
 383                 (*printer)(env, cookie, "%lx %d:%d %lx %lu %slru",
 384                            (long)vmpage->flags, page_count(vmpage),
 385                            page_mapcount(vmpage), vmpage->private,
 386                            page_index(vmpage),
 387                            list_empty(&vmpage->lru) ? "not-" : "");
 388         }
 389         (*printer)(env, cookie, "\n");
 390         return 0;
 391 }
 392
 393 static const struct cl_page_operations vvp_page_ops = {
 394         .cpo_own           = vvp_page_own,
 395         .cpo_assume     = vvp_page_assume,
 396         .cpo_unassume      = vvp_page_unassume,
 397         .cpo_disown     = vvp_page_disown,
 398         .cpo_vmpage     = ccc_page_vmpage,
 399         .cpo_discard       = vvp_page_discard,
 400         .cpo_delete     = vvp_page_delete,
 401         .cpo_unmap       = vvp_page_unmap,
 402         .cpo_export     = vvp_page_export,
 403         .cpo_is_vmlocked   = vvp_page_is_vmlocked,
 404         .cpo_fini         = vvp_page_fini,
 405         .cpo_print       = vvp_page_print,
 406         .cpo_is_under_lock = ccc_page_is_under_lock,
 407         .io = {
 408                 [CRT_READ] = {
 409                         .cpo_prep       = vvp_page_prep_read,
 410                         .cpo_completion  = vvp_page_completion_read,
 411                         .cpo_make_ready  = ccc_fail,
 412                 },
 413                 [CRT_WRITE] = {
 414                         .cpo_prep       = vvp_page_prep_write,
 415                         .cpo_completion  = vvp_page_completion_write,
 416                         .cpo_make_ready  = vvp_page_make_ready,
 417                 }
 418         }
 419 };
 420
 421 static void vvp_transient_page_verify(const struct cl_page *page)
 422 {
 423         struct inode *inode = ccc_object_inode(page->cp_obj);
 424
 425         LASSERT(!mutex_trylock(&inode->i_mutex));
 426 }
 427
 428 static int vvp_transient_page_own(const struct lu_env *env,
 429                                   const struct cl_page_slice *slice,
 430                                   struct cl_io *unused, int nonblock)
 431 {
 432         vvp_transient_page_verify(slice->cpl_page);
 433         return 0;
 434 }
 435
 436 static void vvp_transient_page_assume(const struct lu_env *env,
 437                                       const struct cl_page_slice *slice,
 438                                       struct cl_io *unused)
 439 {
 440         vvp_transient_page_verify(slice->cpl_page);
 441 }
 442
 443 static void vvp_transient_page_unassume(const struct lu_env *env,
 444                                         const struct cl_page_slice *slice,
 445                                         struct cl_io *unused)
 446 {
 447         vvp_transient_page_verify(slice->cpl_page);
 448 }
 449
 450 static void vvp_transient_page_disown(const struct lu_env *env,
 451                                       const struct cl_page_slice *slice,
 452                                       struct cl_io *unused)
 453 {
 454         vvp_transient_page_verify(slice->cpl_page);
 455 }
 456
 457 static void vvp_transient_page_discard(const struct lu_env *env,
 458                                        const struct cl_page_slice *slice,
 459                                        struct cl_io *unused)
 460 {
 461         struct cl_page *page = slice->cpl_page;
 462
 463         vvp_transient_page_verify(slice->cpl_page);
 464
 465         /*
 466          * For transient pages, remove it from the radix tree.
 467          */
 468         cl_page_delete(env, page);
 469 }
 470
 471 static int vvp_transient_page_is_vmlocked(const struct lu_env *env,
 472                                           const struct cl_page_slice *slice)
 473 {
 474         struct inode    *inode = ccc_object_inode(slice->cpl_obj);
 475         int     locked;
 476
 477         locked = !mutex_trylock(&inode->i_mutex);
 478         if (!locked)
 479                 mutex_unlock(&inode->i_mutex);
 480         return locked ? -EBUSY : -ENODATA;
 481 }
 482
 483 static void
 484 vvp_transient_page_completion(const struct lu_env *env,
 485                               const struct cl_page_slice *slice,
 486                               int ioret)
 487 {
 488         vvp_transient_page_verify(slice->cpl_page);
 489 }
 490
 491 static void vvp_transient_page_fini(const struct lu_env *env,
 492                                     struct cl_page_slice *slice)
 493 {
 494         struct ccc_page *cp = cl2ccc_page(slice);
 495         struct cl_page *clp = slice->cpl_page;
 496         struct ccc_object *clobj = cl2ccc(clp->cp_obj);
 497
 498         vvp_page_fini_common(cp);
 499         LASSERT(!mutex_trylock(&clobj->cob_inode->i_mutex));
 500         clobj->cob_transient_pages--;
 501 }
 502
 503 static const struct cl_page_operations vvp_transient_page_ops = {
 504         .cpo_own           = vvp_transient_page_own,
 505         .cpo_assume     = vvp_transient_page_assume,
 506         .cpo_unassume      = vvp_transient_page_unassume,
 507         .cpo_disown     = vvp_transient_page_disown,
 508         .cpo_discard       = vvp_transient_page_discard,
 509         .cpo_vmpage     = ccc_page_vmpage,
 510         .cpo_fini         = vvp_transient_page_fini,
 511         .cpo_is_vmlocked   = vvp_transient_page_is_vmlocked,
 512         .cpo_print       = vvp_page_print,
 513         .cpo_is_under_lock = ccc_page_is_under_lock,
 514         .io = {
 515                 [CRT_READ] = {
 516                         .cpo_prep       = ccc_transient_page_prep,
 517                         .cpo_completion  = vvp_transient_page_completion,
 518                 },
 519                 [CRT_WRITE] = {
 520                         .cpo_prep       = ccc_transient_page_prep,
 521                         .cpo_completion  = vvp_transient_page_completion,
 522                 }
 523         }
 524 };
 525
 526 int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 527                 struct cl_page *page, struct page *vmpage)
 528 {
 529         struct ccc_page *cpg = cl_object_page_slice(obj, page);
 530
 531         CLOBINVRNT(env, obj, ccc_object_invariant(obj));
 532
 533         cpg->cpg_page = vmpage;
 534         page_cache_get(vmpage);
 535
 536         INIT_LIST_HEAD(&cpg->cpg_pending_linkage);
 537         if (page->cp_type == CPT_CACHEABLE) {
 538                 SetPagePrivate(vmpage);
 539                 vmpage->private = (unsigned long)page;
 540                 cl_page_slice_add(page, &cpg->cpg_cl, obj,
 541                                 &vvp_page_ops);
 542         } else {
 543                 struct ccc_object *clobj = cl2ccc(obj);
 544
 545                 LASSERT(!mutex_trylock(&clobj->cob_inode->i_mutex));
 546                 cl_page_slice_add(page, &cpg->cpg_cl, obj,
 547                                 &vvp_transient_page_ops);
 548                 clobj->cob_transient_pages++;
 549         }
 550         return 0;
 551 }