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 static void vvp_page_fini(const struct lu_env *env,
  56                           struct cl_page_slice *slice,
  57                           struct pagevec *pvec)
  58 {
  59         struct vvp_page *vpg     = cl2vvp_page(slice);
  60         struct page     *vmpage  = vpg->vpg_page;
  61
  62         /*
  63          * vmpage->private was already cleared when page was moved into
  64          * VPG_FREEING state.
  65          */
  66         LASSERT((struct cl_page *)vmpage->private != slice->cpl_page);
  67         LASSERT(vmpage != NULL);
  68         if (pvec) {
  69                 if (!pagevec_add(pvec, vmpage))
  70                         pagevec_release(pvec);
  71         } else {
  72                 put_page(vmpage);
  73         }
  74 }
  75
  76 static int vvp_page_own(const struct lu_env *env,
  77                         const struct cl_page_slice *slice, struct cl_io *io,
  78                         int nonblock)
  79 {
  80         struct vvp_page *vpg    = cl2vvp_page(slice);
  81         struct page     *vmpage = vpg->vpg_page;
  82
  83         ENTRY;
  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
 101         RETURN(0);
 102 }
 103
 104 static void vvp_page_assume(const struct lu_env *env,
 105                             const struct cl_page_slice *slice,
 106                             struct cl_io *unused)
 107 {
 108         struct page *vmpage = cl2vm_page(slice);
 109
 110         LASSERT(vmpage != NULL);
 111         LASSERT(PageLocked(vmpage));
 112         wait_on_page_writeback(vmpage);
 113 }
 114
 115 static void vvp_page_unassume(const struct lu_env *env,
 116                               const struct cl_page_slice *slice,
 117                               struct cl_io *unused)
 118 {
 119         struct page *vmpage = cl2vm_page(slice);
 120
 121         LASSERT(vmpage != NULL);
 122         LASSERT(PageLocked(vmpage));
 123 }
 124
 125 static void vvp_page_disown(const struct lu_env *env,
 126                             const struct cl_page_slice *slice, struct cl_io *io)
 127 {
 128         struct page *vmpage = cl2vm_page(slice);
 129
 130         ENTRY;
 131
 132         LASSERT(vmpage != NULL);
 133         LASSERT(PageLocked(vmpage));
 134
 135         unlock_page(cl2vm_page(slice));
 136
 137         EXIT;
 138 }
 139
 140 static void vvp_page_discard(const struct lu_env *env,
 141                              const struct cl_page_slice *slice,
 142                              struct cl_io *unused)
 143 {
 144         struct page     *vmpage = cl2vm_page(slice);
 145         struct vvp_page *vpg    = cl2vvp_page(slice);
 146
 147         LASSERT(vmpage != NULL);
 148         LASSERT(PageLocked(vmpage));
 149
 150         if (vpg->vpg_defer_uptodate && !vpg->vpg_ra_used && vmpage->mapping)
 151                 ll_ra_stats_inc(vmpage->mapping->host, RA_STAT_DISCARDED);
 152
 153         generic_error_remove_page(vmpage->mapping, vmpage);
 154 }
 155
 156 static void vvp_page_delete(const struct lu_env *env,
 157                             const struct cl_page_slice *slice)
 158 {
 159         struct page      *vmpage = cl2vm_page(slice);
 160         struct cl_page   *page   = slice->cpl_page;
 161         int refc;
 162
 163         LASSERT(PageLocked(vmpage));
 164         LASSERT((struct cl_page *)vmpage->private == page);
 165
 166
 167         /* Drop the reference count held in vvp_page_init */
 168         refc = atomic_dec_return(&page->cp_ref);
 169         LASSERTF(refc >= 1, "page = %p, refc = %d\n", page, refc);
 170
 171         ClearPagePrivate(vmpage);
 172         vmpage->private = 0;
 173         /*
 174          * Reference from vmpage to cl_page is removed, but the reference back
 175          * is still here. It is removed later in vvp_page_fini().
 176          */
 177 }
 178
 179 static int vvp_page_prep_read(const struct lu_env *env,
 180                               const struct cl_page_slice *slice,
 181                               struct cl_io *unused)
 182 {
 183         ENTRY;
 184         /* Skip the page already marked as PG_uptodate. */
 185         RETURN(PageUptodate(cl2vm_page(slice)) ? -EALREADY : 0);
 186 }
 187
 188 static int vvp_page_prep_write(const struct lu_env *env,
 189                                const struct cl_page_slice *slice,
 190                                struct cl_io *unused)
 191 {
 192         struct page *vmpage = cl2vm_page(slice);
 193         struct cl_page *pg = slice->cpl_page;
 194
 195         LASSERT(PageLocked(vmpage));
 196         LASSERT(!PageDirty(vmpage));
 197
 198         /* ll_writepage path is not a sync write, so need to set page writeback
 199          * flag
 200          */
 201         if (pg->cp_sync_io == NULL)
 202                 set_page_writeback(vmpage);
 203
 204         return 0;
 205 }
 206
 207 /**
 208  * Handles page transfer errors at VM level.
 209  *
 210  * This takes inode as a separate argument, because inode on which error is to
 211  * be set can be different from \a vmpage inode in case of direct-io.
 212  */
 213 static void vvp_vmpage_error(struct inode *inode, struct page *vmpage,
 214                              int ioret)
 215 {
 216         struct vvp_object *obj = cl_inode2vvp(inode);
 217
 218         if (ioret == 0) {
 219                 ClearPageError(vmpage);
 220                 obj->vob_discard_page_warned = 0;
 221         } else {
 222                 SetPageError(vmpage);
 223                 if (ioret == -ENOSPC)
 224                         set_bit(AS_ENOSPC, &inode->i_mapping->flags);
 225                 else
 226                         set_bit(AS_EIO, &inode->i_mapping->flags);
 227
 228                 if ((ioret == -ESHUTDOWN || ioret == -EINTR ||
 229                      ioret == -EIO) && obj->vob_discard_page_warned == 0) {
 230                         obj->vob_discard_page_warned = 1;
 231                         ll_dirty_page_discard_warn(inode, ioret);
 232                 }
 233         }
 234 }
 235
 236 static void vvp_page_completion_read(const struct lu_env *env,
 237                                      const struct cl_page_slice *slice,
 238                                      int ioret)
 239 {
 240         struct vvp_page *vpg    = cl2vvp_page(slice);
 241         struct page     *vmpage = vpg->vpg_page;
 242         struct cl_page  *page   = slice->cpl_page;
 243         struct inode    *inode  = vvp_object_inode(page->cp_obj);
 244
 245         ENTRY;
 246         LASSERT(PageLocked(vmpage));
 247         CL_PAGE_HEADER(D_PAGE, env, page, "completing READ with %d\n", ioret);
 248
 249         if (vpg->vpg_defer_uptodate)
 250                 ll_ra_count_put(ll_i2sbi(inode), 1);
 251
 252         if (ioret == 0)  {
 253                 if (!vpg->vpg_defer_uptodate)
 254                         SetPageUptodate(vmpage);
 255         } else if (vpg->vpg_defer_uptodate) {
 256                 vpg->vpg_defer_uptodate = 0;
 257                 if (ioret == -EAGAIN) {
 258                         /* mirror read failed, it needs to destroy the page
 259                          * because subpage would be from wrong osc when trying
 260                          * to read from a new mirror
 261                          */
 262                         generic_error_remove_page(vmpage->mapping, vmpage);
 263                 }
 264         }
 265
 266         if (page->cp_sync_io == NULL)
 267                 unlock_page(vmpage);
 268
 269         EXIT;
 270 }
 271
 272 static void vvp_page_completion_write(const struct lu_env *env,
 273                                       const struct cl_page_slice *slice,
 274                                       int ioret)
 275 {
 276         struct vvp_page *vpg    = cl2vvp_page(slice);
 277         struct cl_page  *pg     = slice->cpl_page;
 278         struct page     *vmpage = vpg->vpg_page;
 279
 280         ENTRY;
 281         CL_PAGE_HEADER(D_PAGE, env, pg, "completing WRITE with %d\n", ioret);
 282
 283         if (pg->cp_sync_io != NULL) {
 284                 LASSERT(PageLocked(vmpage));
 285                 LASSERT(!PageWriteback(vmpage));
 286         } else {
 287                 LASSERT(PageWriteback(vmpage));
 288                 /*
 289                  * Only mark the page error only when it's an async write
 290                  * because applications won't wait for IO to finish.
 291                  */
 292                 vvp_vmpage_error(vvp_object_inode(pg->cp_obj), vmpage, ioret);
 293
 294                 end_page_writeback(vmpage);
 295         }
 296         EXIT;
 297 }
 298
 299 /**
 300  * Implements cl_page_operations::cpo_make_ready() method.
 301  *
 302  * This is called to yank a page from the transfer cache and to send it out as
 303  * a part of transfer. This function try-locks the page. If try-lock failed,
 304  * page is owned by some concurrent IO, and should be skipped (this is bad,
 305  * but hopefully rare situation, as it usually results in transfer being
 306  * shorter than possible).
 307  *
 308  * \retval 0      success, page can be placed into transfer
 309  *
 310  * \retval -EAGAIN page is either used by concurrent IO has been
 311  * truncated. Skip it.
 312  */
 313 static int vvp_page_make_ready(const struct lu_env *env,
 314                                const struct cl_page_slice *slice)
 315 {
 316         struct page *vmpage = cl2vm_page(slice);
 317         struct cl_page *pg = slice->cpl_page;
 318         int result = 0;
 319
 320         lock_page(vmpage);
 321         if (clear_page_dirty_for_io(vmpage)) {
 322                 LASSERT(pg->cp_state == CPS_CACHED);
 323                 /* This actually clears the dirty bit in the radix
 324                  * tree.
 325                  */
 326                 set_page_writeback(vmpage);
 327                 CL_PAGE_HEADER(D_PAGE, env, pg, "readied\n");
 328         } else if (pg->cp_state == CPS_PAGEOUT) {
 329                 /* is it possible for osc_flush_async_page() to already
 330                  * make it ready?
 331                  */
 332                 result = -EALREADY;
 333         } else {
 334                 CL_PAGE_DEBUG(D_ERROR, env, pg, "Unexpecting page state %d.\n",
 335                               pg->cp_state);
 336                 LBUG();
 337         }
 338         unlock_page(vmpage);
 339         RETURN(result);
 340 }
 341
 342 static int vvp_page_print(const struct lu_env *env,
 343                           const struct cl_page_slice *slice,
 344                           void *cookie, lu_printer_t printer)
 345 {
 346         struct vvp_page *vpg    = cl2vvp_page(slice);
 347         struct page     *vmpage = vpg->vpg_page;
 348
 349         (*printer)(env, cookie,
 350                    LUSTRE_VVP_NAME"-page@%p(%d:%d) vm@%p ",
 351                    vpg, vpg->vpg_defer_uptodate, vpg->vpg_ra_used, vmpage);
 352
 353         if (vmpage != NULL) {
 354                 (*printer)(env, cookie, "%lx %d:%d %lx %lu %slru",
 355                            (long)vmpage->flags, page_count(vmpage),
 356                            page_mapcount(vmpage), vmpage->private,
 357                            page_index(vmpage),
 358                            list_empty(&vmpage->lru) ? "not-" : "");
 359         }
 360
 361         (*printer)(env, cookie, "\n");
 362
 363         return 0;
 364 }
 365
 366 static int vvp_page_fail(const struct lu_env *env,
 367                          const struct cl_page_slice *slice)
 368 {
 369         /*
 370          * Cached read?
 371          */
 372         LBUG();
 373
 374         return 0;
 375 }
 376
 377 static const struct cl_page_operations vvp_page_ops = {
 378         .cpo_own           = vvp_page_own,
 379         .cpo_assume        = vvp_page_assume,
 380         .cpo_unassume      = vvp_page_unassume,
 381         .cpo_disown        = vvp_page_disown,
 382         .cpo_discard       = vvp_page_discard,
 383         .cpo_delete        = vvp_page_delete,
 384         .cpo_fini          = vvp_page_fini,
 385         .cpo_print         = vvp_page_print,
 386         .io = {
 387                 [CRT_READ] = {
 388                         .cpo_prep       = vvp_page_prep_read,
 389                         .cpo_completion = vvp_page_completion_read,
 390                         .cpo_make_ready = vvp_page_fail,
 391                 },
 392                 [CRT_WRITE] = {
 393                         .cpo_prep       = vvp_page_prep_write,
 394                         .cpo_completion = vvp_page_completion_write,
 395                         .cpo_make_ready = vvp_page_make_ready,
 396                 },
 397         },
 398 };
 399
 400 static void vvp_transient_page_discard(const struct lu_env *env,
 401                                        const struct cl_page_slice *slice,
 402                                        struct cl_io *unused)
 403 {
 404         struct cl_page *page = slice->cpl_page;
 405
 406         /*
 407          * For transient pages, remove it from the radix tree.
 408          */
 409         cl_page_delete(env, page);
 410 }
 411
 412 static const struct cl_page_operations vvp_transient_page_ops = {
 413         .cpo_discard            = vvp_transient_page_discard,
 414         .cpo_print              = vvp_page_print,
 415 };
 416
 417 int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 418                 struct cl_page *page, pgoff_t index)
 419 {
 420         struct vvp_page *vpg = cl_object_page_slice(obj, page);
 421         struct page     *vmpage = page->cp_vmpage;
 422
 423         CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 424
 425         vpg->vpg_page = vmpage;
 426
 427         if (page->cp_type == CPT_TRANSIENT) {
 428                 /* DIO pages are referenced by userspace, we don't need to take
 429                  * a reference on them. (contrast with get_page() call above)
 430                  */
 431                 cl_page_slice_add(page, &vpg->vpg_cl, obj,
 432                                   &vvp_transient_page_ops);
 433         } else {
 434                 get_page(vmpage);
 435                 /* in cache, decref in vvp_page_delete */
 436                 atomic_inc(&page->cp_ref);
 437                 SetPagePrivate(vmpage);
 438                 vmpage->private = (unsigned long)page;
 439                 cl_page_slice_add(page, &vpg->vpg_cl, obj,
 440                                 &vvp_page_ops);
 441         }
 442
 443         return 0;
 444 }