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, 2017, Intel Corporation.
  27  */
  28 /*
  29  * This file is part of Lustre, http://www.lustre.org/
  30  *
  31  * Implementation of cl_page for VVP layer.
  32  *
  33  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  34  *   Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_LLITE
  38
  39 #include <linux/atomic.h>
  40 #include <linux/bitops.h>
  41 #include <linux/mm.h>
  42 #include <linux/mutex.h>
  43 #include <linux/page-flags.h>
  44 #include <linux/pagemap.h>
  45
  46 #include <libcfs/libcfs.h>
  47 #include "llite_internal.h"
  48 #include "vvp_internal.h"
  49
  50 /*****************************************************************************
  51  *
  52  * Page operations.
  53  *
  54  */
  55
  56 static void vvp_page_fini_common(struct vvp_page *vpg, struct pagevec *pvec)
  57 {
  58         struct page *vmpage = vpg->vpg_page;
  59
  60         LASSERT(vmpage != NULL);
  61         if (pvec) {
  62                 if (!pagevec_add(pvec, vmpage))
  63                         pagevec_release(pvec);
  64         } else {
  65                 put_page(vmpage);
  66         }
  67 }
  68
  69 static void vvp_page_fini(const struct lu_env *env,
  70                           struct cl_page_slice *slice,
  71                           struct pagevec *pvec)
  72 {
  73         struct vvp_page *vpg     = cl2vvp_page(slice);
  74         struct page     *vmpage  = vpg->vpg_page;
  75
  76         /*
  77          * vmpage->private was already cleared when page was moved into
  78          * VPG_FREEING state.
  79          */
  80         LASSERT((struct cl_page *)vmpage->private != slice->cpl_page);
  81         vvp_page_fini_common(vpg, pvec);
  82 }
  83
  84 static int vvp_page_own(const struct lu_env *env,
  85                         const struct cl_page_slice *slice, struct cl_io *io,
  86                         int nonblock)
  87 {
  88         struct vvp_page *vpg    = cl2vvp_page(slice);
  89         struct page     *vmpage = vpg->vpg_page;
  90
  91         ENTRY;
  92
  93         LASSERT(vmpage != NULL);
  94         if (nonblock) {
  95                 if (!trylock_page(vmpage))
  96                         return -EAGAIN;
  97
  98                 if (unlikely(PageWriteback(vmpage))) {
  99                         unlock_page(vmpage);
 100                         return -EAGAIN;
 101                 }
 102
 103                 return 0;
 104         }
 105
 106         lock_page(vmpage);
 107         wait_on_page_writeback(vmpage);
 108
 109         RETURN(0);
 110 }
 111
 112 static void vvp_page_assume(const struct lu_env *env,
 113                             const struct cl_page_slice *slice,
 114                             struct cl_io *unused)
 115 {
 116         struct page *vmpage = cl2vm_page(slice);
 117
 118         LASSERT(vmpage != NULL);
 119         LASSERT(PageLocked(vmpage));
 120         wait_on_page_writeback(vmpage);
 121 }
 122
 123 static void vvp_page_unassume(const struct lu_env *env,
 124                               const struct cl_page_slice *slice,
 125                               struct cl_io *unused)
 126 {
 127         struct page *vmpage = cl2vm_page(slice);
 128
 129         LASSERT(vmpage != NULL);
 130         LASSERT(PageLocked(vmpage));
 131 }
 132
 133 static void vvp_page_disown(const struct lu_env *env,
 134                             const struct cl_page_slice *slice, struct cl_io *io)
 135 {
 136         struct page *vmpage = cl2vm_page(slice);
 137
 138         ENTRY;
 139
 140         LASSERT(vmpage != NULL);
 141         LASSERT(PageLocked(vmpage));
 142
 143         unlock_page(cl2vm_page(slice));
 144
 145         EXIT;
 146 }
 147
 148 static void vvp_page_discard(const struct lu_env *env,
 149                              const struct cl_page_slice *slice,
 150                              struct cl_io *unused)
 151 {
 152         struct page     *vmpage = cl2vm_page(slice);
 153         struct vvp_page *vpg    = cl2vvp_page(slice);
 154
 155         LASSERT(vmpage != NULL);
 156         LASSERT(PageLocked(vmpage));
 157
 158         if (vpg->vpg_defer_uptodate && !vpg->vpg_ra_used && vmpage->mapping)
 159                 ll_ra_stats_inc(vmpage->mapping->host, RA_STAT_DISCARDED);
 160
 161         generic_error_remove_page(vmpage->mapping, vmpage);
 162 }
 163
 164 static void vvp_page_delete(const struct lu_env *env,
 165                             const struct cl_page_slice *slice)
 166 {
 167         struct page      *vmpage = cl2vm_page(slice);
 168         struct cl_page   *page   = slice->cpl_page;
 169         int refc;
 170
 171         LASSERT(PageLocked(vmpage));
 172         LASSERT((struct cl_page *)vmpage->private == page);
 173
 174
 175         /* Drop the reference count held in vvp_page_init */
 176         refc = atomic_dec_return(&page->cp_ref);
 177         LASSERTF(refc >= 1, "page = %p, refc = %d\n", page, refc);
 178
 179         ClearPagePrivate(vmpage);
 180         vmpage->private = 0;
 181
 182         /**
 183          * Vmpage might not be released due page refcount != 2,
 184          * clear Page uptodate here to avoid stale data.
 185          */
 186         ClearPageUptodate(vmpage);
 187         /*
 188          * Reference from vmpage to cl_page is removed, but the reference back
 189          * is still here. It is removed later in vvp_page_fini().
 190          */
 191 }
 192
 193 static void vvp_page_export(const struct lu_env *env,
 194                             const struct cl_page_slice *slice,
 195                             int uptodate)
 196 {
 197         struct page *vmpage = cl2vm_page(slice);
 198
 199         LASSERT(vmpage != NULL);
 200         LASSERT(PageLocked(vmpage));
 201         if (uptodate)
 202                 SetPageUptodate(vmpage);
 203         else
 204                 ClearPageUptodate(vmpage);
 205 }
 206
 207 static int vvp_page_is_vmlocked(const struct lu_env *env,
 208                                 const struct cl_page_slice *slice)
 209 {
 210         return PageLocked(cl2vm_page(slice)) ? -EBUSY : -ENODATA;
 211 }
 212
 213 static int vvp_page_prep_read(const struct lu_env *env,
 214                               const struct cl_page_slice *slice,
 215                               struct cl_io *unused)
 216 {
 217         ENTRY;
 218         /* Skip the page already marked as PG_uptodate. */
 219         RETURN(PageUptodate(cl2vm_page(slice)) ? -EALREADY : 0);
 220 }
 221
 222 static int vvp_page_prep_write(const struct lu_env *env,
 223                                const struct cl_page_slice *slice,
 224                                struct cl_io *unused)
 225 {
 226         struct page *vmpage = cl2vm_page(slice);
 227         struct cl_page *pg = slice->cpl_page;
 228
 229         LASSERT(PageLocked(vmpage));
 230         LASSERT(!PageDirty(vmpage));
 231
 232         /* ll_writepage path is not a sync write, so need to set page writeback
 233          * flag
 234          */
 235         if (pg->cp_sync_io == NULL)
 236                 set_page_writeback(vmpage);
 237
 238         return 0;
 239 }
 240
 241 /**
 242  * Handles page transfer errors at VM level.
 243  *
 244  * This takes inode as a separate argument, because inode on which error is to
 245  * be set can be different from \a vmpage inode in case of direct-io.
 246  */
 247 static void vvp_vmpage_error(struct inode *inode, struct page *vmpage,
 248                              int ioret)
 249 {
 250         struct vvp_object *obj = cl_inode2vvp(inode);
 251
 252         if (ioret == 0) {
 253                 ClearPageError(vmpage);
 254                 obj->vob_discard_page_warned = 0;
 255         } else {
 256                 SetPageError(vmpage);
 257                 if (ioret == -ENOSPC)
 258                         set_bit(AS_ENOSPC, &inode->i_mapping->flags);
 259                 else
 260                         set_bit(AS_EIO, &inode->i_mapping->flags);
 261
 262                 if ((ioret == -ESHUTDOWN || ioret == -EINTR ||
 263                      ioret == -EIO) && obj->vob_discard_page_warned == 0) {
 264                         obj->vob_discard_page_warned = 1;
 265                         ll_dirty_page_discard_warn(vmpage, ioret);
 266                 }
 267         }
 268 }
 269
 270 static void vvp_page_completion_read(const struct lu_env *env,
 271                                      const struct cl_page_slice *slice,
 272                                      int ioret)
 273 {
 274         struct vvp_page *vpg    = cl2vvp_page(slice);
 275         struct page     *vmpage = vpg->vpg_page;
 276         struct cl_page  *page   = slice->cpl_page;
 277         struct inode    *inode  = vvp_object_inode(page->cp_obj);
 278
 279         ENTRY;
 280         LASSERT(PageLocked(vmpage));
 281         CL_PAGE_HEADER(D_PAGE, env, page, "completing READ with %d\n", ioret);
 282
 283         if (vpg->vpg_defer_uptodate)
 284                 ll_ra_count_put(ll_i2sbi(inode), 1);
 285
 286         if (ioret == 0)  {
 287                 if (!vpg->vpg_defer_uptodate)
 288                         cl_page_export(env, page, 1);
 289         } else if (vpg->vpg_defer_uptodate) {
 290                 vpg->vpg_defer_uptodate = 0;
 291                 if (ioret == -EAGAIN) {
 292                         /* mirror read failed, it needs to destroy the page
 293                          * because subpage would be from wrong osc when trying
 294                          * to read from a new mirror
 295                          */
 296                         generic_error_remove_page(vmpage->mapping, vmpage);
 297                 }
 298         }
 299
 300         if (page->cp_sync_io == NULL)
 301                 unlock_page(vmpage);
 302
 303         EXIT;
 304 }
 305
 306 static void vvp_page_completion_write(const struct lu_env *env,
 307                                       const struct cl_page_slice *slice,
 308                                       int ioret)
 309 {
 310         struct vvp_page *vpg    = cl2vvp_page(slice);
 311         struct cl_page  *pg     = slice->cpl_page;
 312         struct page     *vmpage = vpg->vpg_page;
 313
 314         ENTRY;
 315         CL_PAGE_HEADER(D_PAGE, env, pg, "completing WRITE with %d\n", ioret);
 316
 317         if (pg->cp_sync_io != NULL) {
 318                 LASSERT(PageLocked(vmpage));
 319                 LASSERT(!PageWriteback(vmpage));
 320         } else {
 321                 LASSERT(PageWriteback(vmpage));
 322                 /*
 323                  * Only mark the page error only when it's an async write
 324                  * because applications won't wait for IO to finish.
 325                  */
 326                 vvp_vmpage_error(vvp_object_inode(pg->cp_obj), vmpage, ioret);
 327
 328                 end_page_writeback(vmpage);
 329         }
 330         EXIT;
 331 }
 332
 333 /**
 334  * Implements cl_page_operations::cpo_make_ready() method.
 335  *
 336  * This is called to yank a page from the transfer cache and to send it out as
 337  * a part of transfer. This function try-locks the page. If try-lock failed,
 338  * page is owned by some concurrent IO, and should be skipped (this is bad,
 339  * but hopefully rare situation, as it usually results in transfer being
 340  * shorter than possible).
 341  *
 342  * \retval 0      success, page can be placed into transfer
 343  *
 344  * \retval -EAGAIN page is either used by concurrent IO has been
 345  * truncated. Skip it.
 346  */
 347 static int vvp_page_make_ready(const struct lu_env *env,
 348                                const struct cl_page_slice *slice)
 349 {
 350         struct page *vmpage = cl2vm_page(slice);
 351         struct cl_page *pg = slice->cpl_page;
 352         int result = 0;
 353
 354         lock_page(vmpage);
 355         if (clear_page_dirty_for_io(vmpage)) {
 356                 LASSERT(pg->cp_state == CPS_CACHED);
 357                 /* This actually clears the dirty bit in the radix
 358                  * tree.
 359                  */
 360                 set_page_writeback(vmpage);
 361                 CL_PAGE_HEADER(D_PAGE, env, pg, "readied\n");
 362         } else if (pg->cp_state == CPS_PAGEOUT) {
 363                 /* is it possible for osc_flush_async_page() to already
 364                  * make it ready?
 365                  */
 366                 result = -EALREADY;
 367         } else {
 368                 CL_PAGE_DEBUG(D_ERROR, env, pg, "Unexpecting page state %d.\n",
 369                               pg->cp_state);
 370                 LBUG();
 371         }
 372         unlock_page(vmpage);
 373         RETURN(result);
 374 }
 375
 376 static int vvp_page_print(const struct lu_env *env,
 377                           const struct cl_page_slice *slice,
 378                           void *cookie, lu_printer_t printer)
 379 {
 380         struct vvp_page *vpg    = cl2vvp_page(slice);
 381         struct page     *vmpage = vpg->vpg_page;
 382
 383         (*printer)(env, cookie,
 384                    LUSTRE_VVP_NAME"-page@%p(%d:%d) vm@%p ",
 385                    vpg, vpg->vpg_defer_uptodate, vpg->vpg_ra_used, vmpage);
 386
 387         if (vmpage != NULL) {
 388                 (*printer)(env, cookie, "%lx %d:%d %lx %lu %slru",
 389                            (long)vmpage->flags, page_count(vmpage),
 390                            page_mapcount(vmpage), vmpage->private,
 391                            page_index(vmpage),
 392                            list_empty(&vmpage->lru) ? "not-" : "");
 393         }
 394
 395         (*printer)(env, cookie, "\n");
 396
 397         return 0;
 398 }
 399
 400 static int vvp_page_fail(const struct lu_env *env,
 401                          const struct cl_page_slice *slice)
 402 {
 403         /*
 404          * Cached read?
 405          */
 406         LBUG();
 407
 408         return 0;
 409 }
 410
 411 static const struct cl_page_operations vvp_page_ops = {
 412         .cpo_own           = vvp_page_own,
 413         .cpo_assume        = vvp_page_assume,
 414         .cpo_unassume      = vvp_page_unassume,
 415         .cpo_disown        = vvp_page_disown,
 416         .cpo_discard       = vvp_page_discard,
 417         .cpo_delete        = vvp_page_delete,
 418         .cpo_export        = vvp_page_export,
 419         .cpo_is_vmlocked   = vvp_page_is_vmlocked,
 420         .cpo_fini          = vvp_page_fini,
 421         .cpo_print         = vvp_page_print,
 422         .io = {
 423                 [CRT_READ] = {
 424                         .cpo_prep       = vvp_page_prep_read,
 425                         .cpo_completion = vvp_page_completion_read,
 426                         .cpo_make_ready = vvp_page_fail,
 427                 },
 428                 [CRT_WRITE] = {
 429                         .cpo_prep       = vvp_page_prep_write,
 430                         .cpo_completion = vvp_page_completion_write,
 431                         .cpo_make_ready = vvp_page_make_ready,
 432                 },
 433         },
 434 };
 435
 436 static void vvp_transient_page_discard(const struct lu_env *env,
 437                                        const struct cl_page_slice *slice,
 438                                        struct cl_io *unused)
 439 {
 440         struct cl_page *page = slice->cpl_page;
 441
 442         /*
 443          * For transient pages, remove it from the radix tree.
 444          */
 445         cl_page_delete(env, page);
 446 }
 447
 448 static int vvp_transient_page_is_vmlocked(const struct lu_env *env,
 449                                           const struct cl_page_slice *slice)
 450 {
 451         return -EBUSY;
 452 }
 453
 454 static void vvp_transient_page_fini(const struct lu_env *env,
 455                                     struct cl_page_slice *slice,
 456                                     struct pagevec *pvec)
 457 {
 458         struct vvp_page *vpg = cl2vvp_page(slice);
 459         struct vvp_object *clobj = cl2vvp(slice->cpl_obj);
 460
 461         vvp_page_fini_common(vpg, pvec);
 462         atomic_dec(&clobj->vob_transient_pages);
 463 }
 464
 465 static const struct cl_page_operations vvp_transient_page_ops = {
 466         .cpo_discard            = vvp_transient_page_discard,
 467         .cpo_fini               = vvp_transient_page_fini,
 468         .cpo_is_vmlocked        = vvp_transient_page_is_vmlocked,
 469         .cpo_print              = vvp_page_print,
 470 };
 471
 472 int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 473                 struct cl_page *page, pgoff_t index)
 474 {
 475         struct vvp_page *vpg = cl_object_page_slice(obj, page);
 476         struct page     *vmpage = page->cp_vmpage;
 477
 478         CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 479
 480         vpg->vpg_page = vmpage;
 481         get_page(vmpage);
 482
 483         if (page->cp_type == CPT_CACHEABLE) {
 484                 /* in cache, decref in vvp_page_delete */
 485                 atomic_inc(&page->cp_ref);
 486                 SetPagePrivate(vmpage);
 487                 vmpage->private = (unsigned long)page;
 488                 cl_page_slice_add(page, &vpg->vpg_cl, obj,
 489                                 &vvp_page_ops);
 490         } else {
 491                 struct vvp_object *clobj = cl2vvp(obj);
 492
 493                 cl_page_slice_add(page, &vpg->vpg_cl, obj,
 494                                 &vvp_transient_page_ops);
 495                 atomic_inc(&clobj->vob_transient_pages);
 496         }
 497         return 0;
 498 }