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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2011, 2016, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  * Lustre is a trademark of Sun Microsystems, Inc.
  31  *
  32  * Implementation of cl_page for VVP layer.
  33  *
  34  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  35  *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  36  */
  37
  38 #define DEBUG_SUBSYSTEM S_LLITE
  39
  40 #include <linux/atomic.h>
  41 #include <linux/bitops.h>
  42 #include <linux/mm.h>
  43 #include <linux/mutex.h>
  44 #include <linux/page-flags.h>
  45 #include <linux/pagemap.h>
  46
  47 #include <libcfs/libcfs.h>
  48 #include "llite_internal.h"
  49 #include "vvp_internal.h"
  50
  51 /*****************************************************************************
  52  *
  53  * Page operations.
  54  *
  55  */
  56
  57 static void vvp_page_fini_common(struct vvp_page *vpg)
  58 {
  59         struct page *vmpage = vpg->vpg_page;
  60
  61         LASSERT(vmpage != NULL);
  62         put_page(vmpage);
  63 }
  64
  65 static void vvp_page_fini(const struct lu_env *env,
  66                           struct cl_page_slice *slice)
  67 {
  68         struct vvp_page *vpg     = cl2vvp_page(slice);
  69         struct page     *vmpage  = vpg->vpg_page;
  70
  71         /*
  72          * vmpage->private was already cleared when page was moved into
  73          * VPG_FREEING state.
  74          */
  75         LASSERT((struct cl_page *)vmpage->private != slice->cpl_page);
  76         vvp_page_fini_common(vpg);
  77 }
  78
  79 static int vvp_page_own(const struct lu_env *env,
  80                         const struct cl_page_slice *slice, struct cl_io *io,
  81                         int nonblock)
  82 {
  83         struct vvp_page *vpg    = cl2vvp_page(slice);
  84         struct page     *vmpage = vpg->vpg_page;
  85
  86         LASSERT(vmpage != NULL);
  87         if (nonblock) {
  88                 if (!trylock_page(vmpage))
  89                         return -EAGAIN;
  90
  91                 if (unlikely(PageWriteback(vmpage))) {
  92                         unlock_page(vmpage);
  93                         return -EAGAIN;
  94                 }
  95
  96                 return 0;
  97         }
  98
  99         lock_page(vmpage);
 100         wait_on_page_writeback(vmpage);
 101
 102         return 0;
 103 }
 104
 105 static void vvp_page_assume(const struct lu_env *env,
 106                             const struct cl_page_slice *slice,
 107                             struct cl_io *unused)
 108 {
 109         struct page *vmpage = cl2vm_page(slice);
 110
 111         LASSERT(vmpage != NULL);
 112         LASSERT(PageLocked(vmpage));
 113         wait_on_page_writeback(vmpage);
 114 }
 115
 116 static void vvp_page_unassume(const struct lu_env *env,
 117                               const struct cl_page_slice *slice,
 118                               struct cl_io *unused)
 119 {
 120         struct page *vmpage = cl2vm_page(slice);
 121
 122         LASSERT(vmpage != NULL);
 123         LASSERT(PageLocked(vmpage));
 124 }
 125
 126 static void vvp_page_disown(const struct lu_env *env,
 127                             const struct cl_page_slice *slice, struct cl_io *io)
 128 {
 129         struct page *vmpage = cl2vm_page(slice);
 130
 131         LASSERT(vmpage != NULL);
 132         LASSERT(PageLocked(vmpage));
 133
 134         unlock_page(cl2vm_page(slice));
 135 }
 136
 137 static void vvp_page_discard(const struct lu_env *env,
 138                              const struct cl_page_slice *slice,
 139                              struct cl_io *unused)
 140 {
 141         struct page     *vmpage = cl2vm_page(slice);
 142         struct vvp_page *vpg    = cl2vvp_page(slice);
 143
 144         LASSERT(vmpage != NULL);
 145         LASSERT(PageLocked(vmpage));
 146
 147         if (vpg->vpg_defer_uptodate && !vpg->vpg_ra_used)
 148                 ll_ra_stats_inc(vmpage->mapping->host, RA_STAT_DISCARDED);
 149
 150         ll_invalidate_page(vmpage);
 151 }
 152
 153 static void vvp_page_delete(const struct lu_env *env,
 154                             const struct cl_page_slice *slice)
 155 {
 156         struct page      *vmpage = cl2vm_page(slice);
 157         struct inode     *inode  = vmpage->mapping->host;
 158         struct cl_object *obj    = slice->cpl_obj;
 159         struct cl_page   *page   = slice->cpl_page;
 160         int refc;
 161
 162         LASSERT(PageLocked(vmpage));
 163         LASSERT((struct cl_page *)vmpage->private == page);
 164         LASSERT(inode == vvp_object_inode(obj));
 165
 166         /* Drop the reference count held in vvp_page_init */
 167         refc = atomic_dec_return(&page->cp_ref);
 168         LASSERTF(refc >= 1, "page = %p, refc = %d\n", page, refc);
 169
 170         ClearPagePrivate(vmpage);
 171         vmpage->private = 0;
 172         /*
 173          * Reference from vmpage to cl_page is removed, but the reference back
 174          * is still here. It is removed later in vvp_page_fini().
 175          */
 176 }
 177
 178 static void vvp_page_export(const struct lu_env *env,
 179                             const struct cl_page_slice *slice,
 180                             int uptodate)
 181 {
 182         struct page *vmpage = cl2vm_page(slice);
 183
 184         LASSERT(vmpage != NULL);
 185         LASSERT(PageLocked(vmpage));
 186         if (uptodate)
 187                 SetPageUptodate(vmpage);
 188         else
 189                 ClearPageUptodate(vmpage);
 190 }
 191
 192 static int vvp_page_is_vmlocked(const struct lu_env *env,
 193                                 const struct cl_page_slice *slice)
 194 {
 195         return PageLocked(cl2vm_page(slice)) ? -EBUSY : -ENODATA;
 196 }
 197
 198 static int vvp_page_prep_read(const struct lu_env *env,
 199                               const struct cl_page_slice *slice,
 200                               struct cl_io *unused)
 201 {
 202         ENTRY;
 203         /* Skip the page already marked as PG_uptodate. */
 204         RETURN(PageUptodate(cl2vm_page(slice)) ? -EALREADY : 0);
 205 }
 206
 207 static int vvp_page_prep_write(const struct lu_env *env,
 208                                const struct cl_page_slice *slice,
 209                                struct cl_io *unused)
 210 {
 211         struct page *vmpage = cl2vm_page(slice);
 212
 213         LASSERT(PageLocked(vmpage));
 214         LASSERT(!PageDirty(vmpage));
 215
 216         set_page_writeback(vmpage);
 217
 218         return 0;
 219 }
 220
 221 /**
 222  * Handles page transfer errors at VM level.
 223  *
 224  * This takes inode as a separate argument, because inode on which error is to
 225  * be set can be different from \a vmpage inode in case of direct-io.
 226  */
 227 static void vvp_vmpage_error(struct inode *inode, struct page *vmpage, int ioret)
 228 {
 229         struct vvp_object *obj = cl_inode2vvp(inode);
 230
 231         if (ioret == 0) {
 232                 ClearPageError(vmpage);
 233                 obj->vob_discard_page_warned = 0;
 234         } else {
 235                 SetPageError(vmpage);
 236                 if (ioret == -ENOSPC)
 237                         set_bit(AS_ENOSPC, &inode->i_mapping->flags);
 238                 else
 239                         set_bit(AS_EIO, &inode->i_mapping->flags);
 240
 241                 if ((ioret == -ESHUTDOWN || ioret == -EINTR) &&
 242                      obj->vob_discard_page_warned == 0) {
 243                         obj->vob_discard_page_warned = 1;
 244                         ll_dirty_page_discard_warn(vmpage, ioret);
 245                 }
 246         }
 247 }
 248
 249 static void vvp_page_completion_read(const struct lu_env *env,
 250                                      const struct cl_page_slice *slice,
 251                                      int ioret)
 252 {
 253         struct vvp_page *vpg    = cl2vvp_page(slice);
 254         struct page     *vmpage = vpg->vpg_page;
 255         struct cl_page  *page   = slice->cpl_page;
 256         struct inode    *inode  = vvp_object_inode(page->cp_obj);
 257         ENTRY;
 258
 259         LASSERT(PageLocked(vmpage));
 260         CL_PAGE_HEADER(D_PAGE, env, page, "completing READ with %d\n", ioret);
 261
 262         if (vpg->vpg_defer_uptodate)
 263                 ll_ra_count_put(ll_i2sbi(inode), 1);
 264
 265         if (ioret == 0)  {
 266                 if (!vpg->vpg_defer_uptodate)
 267                         cl_page_export(env, page, 1);
 268         } else {
 269                 vpg->vpg_defer_uptodate = 0;
 270         }
 271
 272         if (page->cp_sync_io == NULL)
 273                 unlock_page(vmpage);
 274
 275         EXIT;
 276 }
 277
 278 static void vvp_page_completion_write(const struct lu_env *env,
 279                                       const struct cl_page_slice *slice,
 280                                       int ioret)
 281 {
 282         struct vvp_page *vpg    = cl2vvp_page(slice);
 283         struct cl_page  *pg     = slice->cpl_page;
 284         struct page     *vmpage = vpg->vpg_page;
 285         ENTRY;
 286
 287         LASSERT(ergo(pg->cp_sync_io != NULL, PageLocked(vmpage)));
 288         LASSERT(PageWriteback(vmpage));
 289
 290         CL_PAGE_HEADER(D_PAGE, env, pg, "completing WRITE with %d\n", ioret);
 291
 292         /*
 293          * Only mark the page error only when it's an async write because
 294          * applications won't wait for IO to finish.
 295          */
 296         if (pg->cp_sync_io == NULL)
 297                 vvp_vmpage_error(vvp_object_inode(pg->cp_obj), vmpage, ioret);
 298
 299         end_page_writeback(vmpage);
 300         EXIT;
 301 }
 302
 303 /**
 304  * Implements cl_page_operations::cpo_make_ready() method.
 305  *
 306  * This is called to yank a page from the transfer cache and to send it out as
 307  * a part of transfer. This function try-locks the page. If try-lock failed,
 308  * page is owned by some concurrent IO, and should be skipped (this is bad,
 309  * but hopefully rare situation, as it usually results in transfer being
 310  * shorter than possible).
 311  *
 312  * \retval 0      success, page can be placed into transfer
 313  *
 314  * \retval -EAGAIN page is either used by concurrent IO has been
 315  * truncated. Skip it.
 316  */
 317 static int vvp_page_make_ready(const struct lu_env *env,
 318                                const struct cl_page_slice *slice)
 319 {
 320         struct page *vmpage = cl2vm_page(slice);
 321         struct cl_page *pg = slice->cpl_page;
 322         int result = 0;
 323
 324         lock_page(vmpage);
 325         if (clear_page_dirty_for_io(vmpage)) {
 326                 LASSERT(pg->cp_state == CPS_CACHED);
 327                 /* This actually clears the dirty bit in the radix
 328                  * tree. */
 329                 set_page_writeback(vmpage);
 330                 CL_PAGE_HEADER(D_PAGE, env, pg, "readied\n");
 331         } else if (pg->cp_state == CPS_PAGEOUT) {
 332                 /* is it possible for osc_flush_async_page() to already
 333                  * make it ready? */
 334                 result = -EALREADY;
 335         } else {
 336                 CL_PAGE_DEBUG(D_ERROR, env, pg, "Unexpecting page state %d.\n",
 337                               pg->cp_state);
 338                 LBUG();
 339         }
 340         unlock_page(vmpage);
 341         RETURN(result);
 342 }
 343
 344 static int vvp_page_print(const struct lu_env *env,
 345                           const struct cl_page_slice *slice,
 346                           void *cookie, lu_printer_t printer)
 347 {
 348         struct vvp_page *vpg    = cl2vvp_page(slice);
 349         struct page     *vmpage = vpg->vpg_page;
 350
 351         (*printer)(env, cookie, LUSTRE_VVP_NAME"-page@%p(%d:%d) "
 352                    "vm@%p ",
 353                    vpg, vpg->vpg_defer_uptodate, vpg->vpg_ra_used, vmpage);
 354
 355         if (vmpage != NULL) {
 356                 (*printer)(env, cookie, "%lx %d:%d %lx %lu %slru",
 357                            (long)vmpage->flags, page_count(vmpage),
 358                            page_mapcount(vmpage), vmpage->private,
 359                            page_index(vmpage),
 360                            list_empty(&vmpage->lru) ? "not-" : "");
 361         }
 362
 363         (*printer)(env, cookie, "\n");
 364
 365         return 0;
 366 }
 367
 368 static int vvp_page_fail(const struct lu_env *env,
 369                          const struct cl_page_slice *slice)
 370 {
 371         /*
 372          * Cached read?
 373          */
 374         LBUG();
 375
 376         return 0;
 377 }
 378
 379 static const struct cl_page_operations vvp_page_ops = {
 380         .cpo_own           = vvp_page_own,
 381         .cpo_assume        = vvp_page_assume,
 382         .cpo_unassume      = vvp_page_unassume,
 383         .cpo_disown        = vvp_page_disown,
 384         .cpo_discard       = vvp_page_discard,
 385         .cpo_delete        = vvp_page_delete,
 386         .cpo_export        = vvp_page_export,
 387         .cpo_is_vmlocked   = vvp_page_is_vmlocked,
 388         .cpo_fini          = vvp_page_fini,
 389         .cpo_print         = vvp_page_print,
 390         .io = {
 391                 [CRT_READ] = {
 392                         .cpo_prep       = vvp_page_prep_read,
 393                         .cpo_completion = vvp_page_completion_read,
 394                         .cpo_make_ready = vvp_page_fail,
 395                 },
 396                 [CRT_WRITE] = {
 397                         .cpo_prep       = vvp_page_prep_write,
 398                         .cpo_completion = vvp_page_completion_write,
 399                         .cpo_make_ready = vvp_page_make_ready,
 400                 },
 401         },
 402 };
 403
 404 static int vvp_transient_page_prep(const struct lu_env *env,
 405                                    const struct cl_page_slice *slice,
 406                                    struct cl_io *unused)
 407 {
 408         ENTRY;
 409         /* transient page should always be sent. */
 410         RETURN(0);
 411 }
 412
 413 static void vvp_transient_page_verify(const struct cl_page *page)
 414 {
 415 }
 416
 417 static int vvp_transient_page_own(const struct lu_env *env,
 418                                   const struct cl_page_slice *slice,
 419                                   struct cl_io *unused, int nonblock)
 420 {
 421         vvp_transient_page_verify(slice->cpl_page);
 422         return 0;
 423 }
 424
 425 static void vvp_transient_page_assume(const struct lu_env *env,
 426                                       const struct cl_page_slice *slice,
 427                                       struct cl_io *unused)
 428 {
 429         vvp_transient_page_verify(slice->cpl_page);
 430 }
 431
 432 static void vvp_transient_page_unassume(const struct lu_env *env,
 433                                         const struct cl_page_slice *slice,
 434                                         struct cl_io *unused)
 435 {
 436         vvp_transient_page_verify(slice->cpl_page);
 437 }
 438
 439 static void vvp_transient_page_disown(const struct lu_env *env,
 440                                       const struct cl_page_slice *slice,
 441                                       struct cl_io *unused)
 442 {
 443         vvp_transient_page_verify(slice->cpl_page);
 444 }
 445
 446 static void vvp_transient_page_discard(const struct lu_env *env,
 447                                        const struct cl_page_slice *slice,
 448                                        struct cl_io *unused)
 449 {
 450         struct cl_page *page = slice->cpl_page;
 451
 452         vvp_transient_page_verify(slice->cpl_page);
 453
 454         /*
 455          * For transient pages, remove it from the radix tree.
 456          */
 457         cl_page_delete(env, page);
 458 }
 459
 460 static int vvp_transient_page_is_vmlocked(const struct lu_env *env,
 461                                           const struct cl_page_slice *slice)
 462 {
 463         struct inode    *inode = vvp_object_inode(slice->cpl_obj);
 464         int     locked;
 465
 466         locked = !inode_trylock(inode);
 467         if (!locked)
 468                 inode_unlock(inode);
 469         return locked ? -EBUSY : -ENODATA;
 470 }
 471
 472 static void
 473 vvp_transient_page_completion(const struct lu_env *env,
 474                               const struct cl_page_slice *slice,
 475                               int ioret)
 476 {
 477         vvp_transient_page_verify(slice->cpl_page);
 478 }
 479
 480 static void vvp_transient_page_fini(const struct lu_env *env,
 481                                     struct cl_page_slice *slice)
 482 {
 483         struct vvp_page *vpg = cl2vvp_page(slice);
 484         struct cl_page *clp = slice->cpl_page;
 485         struct vvp_object *clobj = cl2vvp(clp->cp_obj);
 486
 487         vvp_page_fini_common(vpg);
 488         atomic_dec(&clobj->vob_transient_pages);
 489 }
 490
 491 static const struct cl_page_operations vvp_transient_page_ops = {
 492         .cpo_own                = vvp_transient_page_own,
 493         .cpo_assume             = vvp_transient_page_assume,
 494         .cpo_unassume           = vvp_transient_page_unassume,
 495         .cpo_disown             = vvp_transient_page_disown,
 496         .cpo_discard            = vvp_transient_page_discard,
 497         .cpo_fini               = vvp_transient_page_fini,
 498         .cpo_is_vmlocked        = vvp_transient_page_is_vmlocked,
 499         .cpo_print              = vvp_page_print,
 500         .io = {
 501                 [CRT_READ] = {
 502                         .cpo_prep       = vvp_transient_page_prep,
 503                         .cpo_completion = vvp_transient_page_completion,
 504                 },
 505                 [CRT_WRITE] = {
 506                         .cpo_prep       = vvp_transient_page_prep,
 507                         .cpo_completion = vvp_transient_page_completion,
 508                 }
 509         }
 510 };
 511
 512 int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 513                 struct cl_page *page, pgoff_t index)
 514 {
 515         struct vvp_page *vpg = cl_object_page_slice(obj, page);
 516         struct page     *vmpage = page->cp_vmpage;
 517
 518         CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 519
 520         vpg->vpg_page = vmpage;
 521         get_page(vmpage);
 522
 523         if (page->cp_type == CPT_CACHEABLE) {
 524                 /* in cache, decref in vvp_page_delete */
 525                 atomic_inc(&page->cp_ref);
 526                 SetPagePrivate(vmpage);
 527                 vmpage->private = (unsigned long)page;
 528                 cl_page_slice_add(page, &vpg->vpg_cl, obj, index,
 529                                 &vvp_page_ops);
 530         } else {
 531                 struct vvp_object *clobj = cl2vvp(obj);
 532
 533                 cl_page_slice_add(page, &vpg->vpg_cl, obj, index,
 534                                 &vvp_transient_page_ops);
 535                 atomic_inc(&clobj->vob_transient_pages);
 536         }
 537         return 0;
 538 }