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.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, 2015, 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 "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)
  57 {
  58         struct page *vmpage = vpg->vpg_page;
  59
  60         LASSERT(vmpage);
  61         put_page(vmpage);
  62 }
  63
  64 static void vvp_page_fini(const struct lu_env *env,
  65                           struct cl_page_slice *slice)
  66 {
  67         struct vvp_page *vpg     = cl2vvp_page(slice);
  68         struct page     *vmpage  = vpg->vpg_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(vpg);
  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 vvp_page *vpg    = cl2vvp_page(slice);
  83         struct page     *vmpage = vpg->vpg_page;
  84
  85         LASSERT(vmpage);
  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);
 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);
 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         LASSERT(vmpage);
 131         LASSERT(PageLocked(vmpage));
 132
 133         unlock_page(cl2vm_page(slice));
 134 }
 135
 136 static void vvp_page_discard(const struct lu_env *env,
 137                              const struct cl_page_slice *slice,
 138                              struct cl_io *unused)
 139 {
 140         struct page        *vmpage  = cl2vm_page(slice);
 141         struct vvp_page      *vpg     = cl2vvp_page(slice);
 142
 143         LASSERT(vmpage);
 144         LASSERT(PageLocked(vmpage));
 145
 146         if (vpg->vpg_defer_uptodate && !vpg->vpg_ra_used)
 147                 ll_ra_stats_inc(vmpage->mapping->host, RA_STAT_DISCARDED);
 148
 149         ll_invalidate_page(vmpage);
 150 }
 151
 152 static void vvp_page_delete(const struct lu_env *env,
 153                             const struct cl_page_slice *slice)
 154 {
 155         struct page       *vmpage = cl2vm_page(slice);
 156         struct inode     *inode  = vmpage->mapping->host;
 157         struct cl_object *obj    = slice->cpl_obj;
 158         struct cl_page   *page   = slice->cpl_page;
 159         int refc;
 160
 161         LASSERT(PageLocked(vmpage));
 162         LASSERT((struct cl_page *)vmpage->private == page);
 163         LASSERT(inode == vvp_object_inode(obj));
 164
 165         /* Drop the reference count held in vvp_page_init */
 166         refc = atomic_dec_return(&page->cp_ref);
 167         LASSERTF(refc >= 1, "page = %p, refc = %d\n", page, refc);
 168
 169         ClearPagePrivate(vmpage);
 170         vmpage->private = 0;
 171         /*
 172          * Reference from vmpage to cl_page is removed, but the reference back
 173          * is still here. It is removed later in vvp_page_fini().
 174          */
 175 }
 176
 177 static void vvp_page_export(const struct lu_env *env,
 178                             const struct cl_page_slice *slice,
 179                             int uptodate)
 180 {
 181         struct page *vmpage = cl2vm_page(slice);
 182
 183         LASSERT(vmpage);
 184         LASSERT(PageLocked(vmpage));
 185         if (uptodate)
 186                 SetPageUptodate(vmpage);
 187         else
 188                 ClearPageUptodate(vmpage);
 189 }
 190
 191 static int vvp_page_is_vmlocked(const struct lu_env *env,
 192                                 const struct cl_page_slice *slice)
 193 {
 194         return PageLocked(cl2vm_page(slice)) ? -EBUSY : -ENODATA;
 195 }
 196
 197 static int vvp_page_prep_read(const struct lu_env *env,
 198                               const struct cl_page_slice *slice,
 199                               struct cl_io *unused)
 200 {
 201         /* Skip the page already marked as PG_uptodate. */
 202         return PageUptodate(cl2vm_page(slice)) ? -EALREADY : 0;
 203 }
 204
 205 static int vvp_page_prep_write(const struct lu_env *env,
 206                                const struct cl_page_slice *slice,
 207                                struct cl_io *unused)
 208 {
 209         struct page *vmpage = cl2vm_page(slice);
 210         struct cl_page *pg = slice->cpl_page;
 211
 212         LASSERT(PageLocked(vmpage));
 213         LASSERT(!PageDirty(vmpage));
 214
 215         /* ll_writepage path is not a sync write, so need to set page writeback
 216          * flag
 217          */
 218         if (!pg->cp_sync_io)
 219                 set_page_writeback(vmpage);
 220
 221         return 0;
 222 }
 223
 224 /**
 225  * Handles page transfer errors at VM level.
 226  *
 227  * This takes inode as a separate argument, because inode on which error is to
 228  * be set can be different from \a vmpage inode in case of direct-io.
 229  */
 230 static void vvp_vmpage_error(struct inode *inode, struct page *vmpage,
 231                              int ioret)
 232 {
 233         struct vvp_object *obj = cl_inode2vvp(inode);
 234
 235         if (ioret == 0) {
 236                 ClearPageError(vmpage);
 237                 obj->vob_discard_page_warned = 0;
 238         } else {
 239                 SetPageError(vmpage);
 240                 mapping_set_error(inode->i_mapping, ioret);
 241
 242                 if ((ioret == -ESHUTDOWN || ioret == -EINTR) &&
 243                     obj->vob_discard_page_warned == 0) {
 244                         obj->vob_discard_page_warned = 1;
 245                         ll_dirty_page_discard_warn(vmpage, ioret);
 246                 }
 247         }
 248 }
 249
 250 static void vvp_page_completion_read(const struct lu_env *env,
 251                                      const struct cl_page_slice *slice,
 252                                      int ioret)
 253 {
 254         struct vvp_page *vpg    = cl2vvp_page(slice);
 255         struct page     *vmpage = vpg->vpg_page;
 256         struct cl_page  *page   = slice->cpl_page;
 257         struct inode    *inode  = vvp_object_inode(page->cp_obj);
 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)
 273                 unlock_page(vmpage);
 274 }
 275
 276 static void vvp_page_completion_write(const struct lu_env *env,
 277                                       const struct cl_page_slice *slice,
 278                                       int ioret)
 279 {
 280         struct vvp_page *vpg     = cl2vvp_page(slice);
 281         struct cl_page  *pg     = slice->cpl_page;
 282         struct page     *vmpage = vpg->vpg_page;
 283
 284         CL_PAGE_HEADER(D_PAGE, env, pg, "completing WRITE with %d\n", ioret);
 285
 286         if (pg->cp_sync_io) {
 287                 LASSERT(PageLocked(vmpage));
 288                 LASSERT(!PageWriteback(vmpage));
 289         } else {
 290                 LASSERT(PageWriteback(vmpage));
 291                 /*
 292                  * Only mark the page error only when it's an async write
 293                  * because applications won't wait for IO to finish.
 294                  */
 295                 vvp_vmpage_error(vvp_object_inode(pg->cp_obj), vmpage, ioret);
 296
 297                 end_page_writeback(vmpage);
 298         }
 299 }
 300
 301 /**
 302  * Implements cl_page_operations::cpo_make_ready() method.
 303  *
 304  * This is called to yank a page from the transfer cache and to send it out as
 305  * a part of transfer. This function try-locks the page. If try-lock failed,
 306  * page is owned by some concurrent IO, and should be skipped (this is bad,
 307  * but hopefully rare situation, as it usually results in transfer being
 308  * shorter than possible).
 309  *
 310  * \retval 0      success, page can be placed into transfer
 311  *
 312  * \retval -EAGAIN page is either used by concurrent IO has been
 313  * truncated. Skip it.
 314  */
 315 static int vvp_page_make_ready(const struct lu_env *env,
 316                                const struct cl_page_slice *slice)
 317 {
 318         struct page *vmpage = cl2vm_page(slice);
 319         struct cl_page *pg = slice->cpl_page;
 320         int result = 0;
 321
 322         lock_page(vmpage);
 323         if (clear_page_dirty_for_io(vmpage)) {
 324                 LASSERT(pg->cp_state == CPS_CACHED);
 325                 /* This actually clears the dirty bit in the radix tree. */
 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, LUSTRE_VVP_NAME "-page@%p(%d:%d) vm@%p ",
 350                    vpg, vpg->vpg_defer_uptodate, vpg->vpg_ra_used, vmpage);
 351         if (vmpage) {
 352                 (*printer)(env, cookie, "%lx %d:%d %lx %lu %slru",
 353                            (long)vmpage->flags, page_count(vmpage),
 354                            page_mapcount(vmpage), vmpage->private,
 355                            vmpage->index,
 356                            list_empty(&vmpage->lru) ? "not-" : "");
 357         }
 358
 359         (*printer)(env, cookie, "\n");
 360
 361         return 0;
 362 }
 363
 364 static int vvp_page_fail(const struct lu_env *env,
 365                          const struct cl_page_slice *slice)
 366 {
 367         /*
 368          * Cached read?
 369          */
 370         LBUG();
 371
 372         return 0;
 373 }
 374
 375 static const struct cl_page_operations vvp_page_ops = {
 376         .cpo_own           = vvp_page_own,
 377         .cpo_assume     = vvp_page_assume,
 378         .cpo_unassume      = vvp_page_unassume,
 379         .cpo_disown     = vvp_page_disown,
 380         .cpo_discard       = vvp_page_discard,
 381         .cpo_delete     = vvp_page_delete,
 382         .cpo_export     = vvp_page_export,
 383         .cpo_is_vmlocked   = vvp_page_is_vmlocked,
 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 int vvp_transient_page_prep(const struct lu_env *env,
 401                                    const struct cl_page_slice *slice,
 402                                    struct cl_io *unused)
 403 {
 404         /* transient page should always be sent. */
 405         return 0;
 406 }
 407
 408 static int vvp_transient_page_own(const struct lu_env *env,
 409                                   const struct cl_page_slice *slice,
 410                                   struct cl_io *unused, int nonblock)
 411 {
 412         return 0;
 413 }
 414
 415 static void vvp_transient_page_assume(const struct lu_env *env,
 416                                       const struct cl_page_slice *slice,
 417                                       struct cl_io *unused)
 418 {
 419 }
 420
 421 static void vvp_transient_page_unassume(const struct lu_env *env,
 422                                         const struct cl_page_slice *slice,
 423                                         struct cl_io *unused)
 424 {
 425 }
 426
 427 static void vvp_transient_page_disown(const struct lu_env *env,
 428                                       const struct cl_page_slice *slice,
 429                                       struct cl_io *unused)
 430 {
 431 }
 432
 433 static void vvp_transient_page_discard(const struct lu_env *env,
 434                                        const struct cl_page_slice *slice,
 435                                        struct cl_io *unused)
 436 {
 437         struct cl_page *page = slice->cpl_page;
 438
 439         /*
 440          * For transient pages, remove it from the radix tree.
 441          */
 442         cl_page_delete(env, page);
 443 }
 444
 445 static int vvp_transient_page_is_vmlocked(const struct lu_env *env,
 446                                           const struct cl_page_slice *slice)
 447 {
 448         struct inode    *inode = vvp_object_inode(slice->cpl_obj);
 449         int     locked;
 450
 451         locked = !inode_trylock(inode);
 452         if (!locked)
 453                 inode_unlock(inode);
 454         return locked ? -EBUSY : -ENODATA;
 455 }
 456
 457 static void
 458 vvp_transient_page_completion(const struct lu_env *env,
 459                               const struct cl_page_slice *slice,
 460                               int ioret)
 461 {
 462 }
 463
 464 static void vvp_transient_page_fini(const struct lu_env *env,
 465                                     struct cl_page_slice *slice)
 466 {
 467         struct vvp_page *vpg = cl2vvp_page(slice);
 468         struct cl_page *clp = slice->cpl_page;
 469         struct vvp_object *clobj = cl2vvp(clp->cp_obj);
 470
 471         vvp_page_fini_common(vpg);
 472         atomic_dec(&clobj->vob_transient_pages);
 473 }
 474
 475 static const struct cl_page_operations vvp_transient_page_ops = {
 476         .cpo_own           = vvp_transient_page_own,
 477         .cpo_assume     = vvp_transient_page_assume,
 478         .cpo_unassume      = vvp_transient_page_unassume,
 479         .cpo_disown     = vvp_transient_page_disown,
 480         .cpo_discard       = vvp_transient_page_discard,
 481         .cpo_fini         = vvp_transient_page_fini,
 482         .cpo_is_vmlocked   = vvp_transient_page_is_vmlocked,
 483         .cpo_print       = vvp_page_print,
 484         .io = {
 485                 [CRT_READ] = {
 486                         .cpo_prep       = vvp_transient_page_prep,
 487                         .cpo_completion  = vvp_transient_page_completion,
 488                 },
 489                 [CRT_WRITE] = {
 490                         .cpo_prep       = vvp_transient_page_prep,
 491                         .cpo_completion  = vvp_transient_page_completion,
 492                 }
 493         }
 494 };
 495
 496 int vvp_page_init(const struct lu_env *env, struct cl_object *obj,
 497                   struct cl_page *page, pgoff_t index)
 498 {
 499         struct vvp_page *vpg = cl_object_page_slice(obj, page);
 500         struct page     *vmpage = page->cp_vmpage;
 501
 502         CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 503
 504         vpg->vpg_page = vmpage;
 505         get_page(vmpage);
 506
 507         if (page->cp_type == CPT_CACHEABLE) {
 508                 /* in cache, decref in vvp_page_delete */
 509                 atomic_inc(&page->cp_ref);
 510                 SetPagePrivate(vmpage);
 511                 vmpage->private = (unsigned long)page;
 512                 cl_page_slice_add(page, &vpg->vpg_cl, obj, index,
 513                                   &vvp_page_ops);
 514         } else {
 515                 struct vvp_object *clobj = cl2vvp(obj);
 516
 517                 cl_page_slice_add(page, &vpg->vpg_cl, obj, index,
 518                                   &vvp_transient_page_ops);
 519                 atomic_inc(&clobj->vob_transient_pages);
 520         }
 521         return 0;
 522 }