lustre/llite/rw.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * Lustre Lite I/O page cache routines shared by different kernel revs
   5  *
   6  *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
   7  *
   8  *   This file is part of Lustre, http://www.lustre.org.
   9  *
  10  *   Lustre is free software; you can redistribute it and/or
  11  *   modify it under the terms of version 2 of the GNU General Public
  12  *   License as published by the Free Software Foundation.
  13  *
  14  *   Lustre is distributed in the hope that it will be useful,
  15  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *   GNU General Public License for more details.
  18  *
  19  *   You should have received a copy of the GNU General Public License
  20  *   along with Lustre; if not, write to the Free Software
  21  *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  */
  23
  24 #include <linux/config.h>
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/string.h>
  28 #include <linux/stat.h>
  29 #include <linux/errno.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/unistd.h>
  32 #include <linux/version.h>
  33 #include <asm/system.h>
  34 #include <asm/uaccess.h>
  35
  36 #include <linux/fs.h>
  37 #include <linux/stat.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/segment.h>
  40 #include <linux/mm.h>
  41 #include <linux/pagemap.h>
  42 #include <linux/smp_lock.h>
  43
  44 #define DEBUG_SUBSYSTEM S_LLITE
  45
  46 #include <linux/lustre_mds.h>
  47 #include <linux/lustre_lite.h>
  48 #include "llite_internal.h"
  49 #include <linux/lustre_compat25.h>
  50
  51 #ifndef list_for_each_prev_safe
  52 #define list_for_each_prev_safe(pos, n, head) \
  53         for (pos = (head)->prev, n = pos->prev; pos != (head); \
  54                 pos = n, n = pos->prev )
  55 #endif
  56
  57 kmem_cache_t *ll_async_page_slab = NULL;
  58 size_t ll_async_page_slab_size = 0;
  59
  60 /* SYNCHRONOUS I/O to object storage for an inode */
  61 static int ll_brw(int cmd, struct inode *inode, struct obdo *oa,
  62                   struct page *page, int flags)
  63 {
  64         struct ll_inode_info *lli = ll_i2info(inode);
  65         struct lov_stripe_md *lsm = lli->lli_smd;
  66         struct brw_page pg;
  67         int rc;
  68         ENTRY;
  69
  70         pg.pg = page;
  71         pg.off = ((obd_off)page->index) << PAGE_SHIFT;
  72
  73         if ((cmd & OBD_BRW_WRITE) && (pg.off + PAGE_SIZE > inode->i_size))
  74                 pg.count = inode->i_size % PAGE_SIZE;
  75         else
  76                 pg.count = PAGE_SIZE;
  77
  78         LL_CDEBUG_PAGE(D_PAGE, page, "%s %d bytes ino %lu at "LPU64"/"LPX64"\n",
  79                        cmd & OBD_BRW_WRITE ? "write" : "read", pg.count,
  80                        inode->i_ino, pg.off, pg.off);
  81         if (pg.count == 0) {
  82                 CERROR("ZERO COUNT: ino %lu: size %p:%Lu(%p:%Lu) idx %lu off "
  83                        LPU64"\n",
  84                        inode->i_ino, inode, inode->i_size, page->mapping->host,
  85                        page->mapping->host->i_size, page->index, pg.off);
  86         }
  87
  88         pg.flag = flags;
  89
  90         if (cmd & OBD_BRW_WRITE)
  91                 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
  92                                     LPROC_LL_BRW_WRITE, pg.count);
  93         else
  94                 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
  95                                     LPROC_LL_BRW_READ, pg.count);
  96         rc = obd_brw(cmd, ll_i2obdexp(inode), oa, lsm, 1, &pg, NULL);
  97         if (rc == 0)
  98                 obdo_to_inode(inode, oa, OBD_MD_FLBLOCKS);
  99         else if (rc != -EIO)
 100                 CERROR("error from obd_brw: rc = %d\n", rc);
 101         RETURN(rc);
 102 }
 103
 104 /* this isn't where truncate starts.   roughly:
 105  * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate
 106  * we grab the lock back in setattr_raw to avoid races.
 107  *
 108  * must be called with lli_size_sem held */
 109 void ll_truncate(struct inode *inode)
 110 {
 111         struct ll_inode_info *lli = ll_i2info(inode);
 112         struct lov_stripe_md *lsm = lli->lli_smd;
 113         struct obdo oa;
 114         int rc;
 115         ENTRY;
 116         CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p) to %Lu=%#Lx\n",inode->i_ino,
 117                inode->i_generation, inode, inode->i_size, inode->i_size);
 118
 119         if (lli->lli_size_pid != current->pid) {
 120                 EXIT;
 121                 return;
 122         }
 123
 124         if (!lsm) {
 125                 CDEBUG(D_INODE, "truncate on inode %lu with no objects\n",
 126                        inode->i_ino);
 127                 GOTO(out_unlock, 0);
 128         }
 129
 130         LASSERT(atomic_read(&lli->lli_size_sem.count) <= 0);
 131
 132         /* XXX I'm pretty sure this is a hack to paper over a more fundamental
 133          * race condition. */
 134         if (lov_merge_size(lsm, 0) == inode->i_size) {
 135                 CDEBUG(D_VFSTRACE, "skipping punch for obj "LPX64", %Lu=%#Lx\n",
 136                        lsm->lsm_object_id, inode->i_size, inode->i_size);
 137                 GOTO(out_unlock, 0);
 138         }
 139
 140         if (unlikely((ll_i2sbi(inode)->ll_flags & LL_SBI_CHECKSUM) &&
 141                      (inode->i_size & ~PAGE_MASK))) {
 142                 /* If the truncate leaves behind a partial page, update its
 143                  * checksum. */
 144                 struct page *page = find_get_page(inode->i_mapping,
 145                                              inode->i_size >> PAGE_CACHE_SHIFT);
 146                 if (page != NULL) {
 147                         struct ll_async_page *llap = llap_cast_private(page);
 148                         if (llap != NULL) {
 149                                 llap->llap_checksum =
 150                                         crc32_le(0, kmap(page), PAGE_SIZE);
 151                                 kunmap(page);
 152                         }
 153                         page_cache_release(page);
 154                 }
 155         }
 156
 157         CDEBUG(D_INFO, "calling punch for "LPX64" (new size %Lu=%#Lx)\n",
 158                lsm->lsm_object_id, inode->i_size, inode->i_size);
 159
 160         oa.o_id = lsm->lsm_object_id;
 161         oa.o_valid = OBD_MD_FLID;
 162         obdo_from_inode(&oa, inode, OBD_MD_FLTYPE | OBD_MD_FLMODE |
 163                         OBD_MD_FLATIME |OBD_MD_FLMTIME |OBD_MD_FLCTIME);
 164
 165         obd_adjust_kms(ll_i2obdexp(inode), lsm, inode->i_size, 1);
 166
 167         lli->lli_size_pid = 0;
 168         up(&lli->lli_size_sem);
 169
 170         rc = obd_punch(ll_i2obdexp(inode), &oa, lsm, inode->i_size,
 171                        OBD_OBJECT_EOF, NULL);
 172         if (rc)
 173                 CERROR("obd_truncate fails (%d) ino %lu\n", rc, inode->i_ino);
 174         else
 175                 obdo_to_inode(inode, &oa, OBD_MD_FLSIZE|OBD_MD_FLBLOCKS|
 176                               OBD_MD_FLATIME | OBD_MD_FLMTIME |
 177                               OBD_MD_FLCTIME);
 178         EXIT;
 179         return;
 180
 181  out_unlock:
 182         lli->lli_size_pid = 0;
 183         up(&lli->lli_size_sem);
 184 } /* ll_truncate */
 185
 186 int ll_prepare_write(struct file *file, struct page *page, unsigned from,
 187                      unsigned to)
 188 {
 189         struct inode *inode = page->mapping->host;
 190         struct ll_inode_info *lli = ll_i2info(inode);
 191         struct lov_stripe_md *lsm = lli->lli_smd;
 192         obd_off offset = ((obd_off)page->index) << PAGE_SHIFT;
 193         struct brw_page pga;
 194         struct obdo oa;
 195         __u64 kms;
 196         int rc = 0;
 197         ENTRY;
 198
 199         LASSERT(PageLocked(page));
 200         (void)llap_cast_private(page); /* assertion */
 201
 202         /* Check to see if we should return -EIO right away */
 203         pga.pg = page;
 204         pga.off = offset;
 205         pga.count = PAGE_SIZE;
 206         pga.flag = 0;
 207
 208         oa.o_id = lsm->lsm_object_id;
 209         oa.o_mode = inode->i_mode;
 210         oa.o_valid = OBD_MD_FLID | OBD_MD_FLMODE | OBD_MD_FLTYPE;
 211
 212         rc = obd_brw(OBD_BRW_CHECK, ll_i2obdexp(inode), &oa, lsm, 1, &pga,
 213                      NULL);
 214         if (rc)
 215                 RETURN(rc);
 216
 217         if (PageUptodate(page)) {
 218                 LL_CDEBUG_PAGE(D_PAGE, page, "uptodate\n");
 219                 RETURN(0);
 220         }
 221
 222         /* We're completely overwriting an existing page, so _don't_ set it up
 223          * to date until commit_write */
 224         if (from == 0 && to == PAGE_SIZE) {
 225                 LL_CDEBUG_PAGE(D_PAGE, page, "full page write\n");
 226                 POISON_PAGE(page, 0x11);
 227                 RETURN(0);
 228         }
 229
 230         /* If are writing to a new page, no need to read old data.  The extent
 231          * locking will have updated the KMS, and for our purposes here we can
 232          * treat it like i_size. */
 233         down(&lli->lli_size_sem);
 234         kms = lov_merge_size(lsm, 1);
 235         up(&lli->lli_size_sem);
 236         if (kms <= offset) {
 237                 LL_CDEBUG_PAGE(D_PAGE, page, "kms "LPU64" <= offset "LPU64"\n",
 238                                kms, offset);
 239                 memset(kmap(page), 0, PAGE_SIZE);
 240                 kunmap(page);
 241                 GOTO(prepare_done, rc = 0);
 242         }
 243
 244         /* XXX could be an async ocp read.. read-ahead? */
 245         rc = ll_brw(OBD_BRW_READ, inode, &oa, page, 0);
 246         if (rc == 0) {
 247                 /* bug 1598: don't clobber blksize */
 248                 oa.o_valid &= ~(OBD_MD_FLSIZE | OBD_MD_FLBLKSZ);
 249                 obdo_refresh_inode(inode, &oa, oa.o_valid);
 250         }
 251
 252         EXIT;
 253  prepare_done:
 254         if (rc == 0)
 255                 SetPageUptodate(page);
 256
 257         return rc;
 258 }
 259
 260 static int ll_ap_make_ready(void *data, int cmd)
 261 {
 262         struct ll_async_page *llap;
 263         struct page *page;
 264         ENTRY;
 265
 266         llap = LLAP_FROM_COOKIE(data);
 267         page = llap->llap_page;
 268
 269         LASSERT(!(cmd & OBD_BRW_READ));
 270
 271         /* we're trying to write, but the page is locked.. come back later */
 272         if (TryLockPage(page))
 273                 RETURN(-EAGAIN);
 274
 275         LL_CDEBUG_PAGE(D_PAGE, page, "made ready\n");
 276         page_cache_get(page);
 277
 278         /* if we left PageDirty we might get another writepage call
 279          * in the future.  list walkers are bright enough
 280          * to check page dirty so we can leave it on whatever list
 281          * its on.  XXX also, we're called with the cli list so if
 282          * we got the page cache list we'd create a lock inversion
 283          * with the removepage path which gets the page lock then the
 284          * cli lock */
 285         clear_page_dirty(page);
 286         RETURN(0);
 287 }
 288
 289 /* We have two reasons for giving llite the opportunity to change the
 290  * write length of a given queued page as it builds the RPC containing
 291  * the page:
 292  *
 293  * 1) Further extending writes may have landed in the page cache
 294  *    since a partial write first queued this page requiring us
 295  *    to write more from the page cache.  (No further races are possible, since
 296  *    by the time this is called, the page is locked.)
 297  * 2) We might have raced with truncate and want to avoid performing
 298  *    write RPCs that are just going to be thrown away by the
 299  *    truncate's punch on the storage targets.
 300  *
 301  * The kms serves these purposes as it is set at both truncate and extending
 302  * writes.
 303  */
 304 static int ll_ap_refresh_count(void *data, int cmd)
 305 {
 306         struct ll_inode_info *lli;
 307         struct ll_async_page *llap;
 308         struct lov_stripe_md *lsm;
 309         struct page *page;
 310         __u64 kms;
 311         ENTRY;
 312
 313         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
 314         LASSERT(cmd != OBD_BRW_READ);
 315
 316         llap = LLAP_FROM_COOKIE(data);
 317         page = llap->llap_page;
 318         lli = ll_i2info(page->mapping->host);
 319         lsm = lli->lli_smd;
 320
 321         //down(&lli->lli_size_sem);
 322         kms = lov_merge_size(lsm, 1);
 323         //up(&lli->lli_size_sem);
 324
 325         /* catch race with truncate */
 326         if (((__u64)page->index << PAGE_SHIFT) >= kms)
 327                 return 0;
 328
 329         /* catch sub-page write at end of file */
 330         if (((__u64)page->index << PAGE_SHIFT) + PAGE_SIZE > kms)
 331                 return kms % PAGE_SIZE;
 332
 333         return PAGE_SIZE;
 334 }
 335
 336 void ll_inode_fill_obdo(struct inode *inode, int cmd, struct obdo *oa)
 337 {
 338         struct lov_stripe_md *lsm;
 339         obd_flag valid_flags;
 340
 341         lsm = ll_i2info(inode)->lli_smd;
 342
 343         oa->o_id = lsm->lsm_object_id;
 344         oa->o_valid = OBD_MD_FLID;
 345         valid_flags = OBD_MD_FLTYPE | OBD_MD_FLATIME;
 346         if (cmd & OBD_BRW_WRITE) {
 347                 oa->o_valid |= OBD_MD_FLIFID | OBD_MD_FLEPOCH;
 348                 mdc_pack_fid(obdo_fid(oa), inode->i_ino, 0, inode->i_mode);
 349                 oa->o_easize = ll_i2info(inode)->lli_io_epoch;
 350                 oa->o_uid = inode->i_uid;
 351                 oa->o_gid = inode->i_gid;
 352
 353                 valid_flags |= OBD_MD_FLMTIME | OBD_MD_FLCTIME |
 354                                OBD_MD_FLUID | OBD_MD_FLGID;
 355         }
 356
 357         obdo_from_inode(oa, inode, valid_flags);
 358 }
 359
 360 static void ll_ap_fill_obdo(void *data, int cmd, struct obdo *oa)
 361 {
 362         struct ll_async_page *llap;
 363         ENTRY;
 364
 365         llap = LLAP_FROM_COOKIE(data);
 366         ll_inode_fill_obdo(llap->llap_page->mapping->host, cmd, oa);
 367         EXIT;
 368 }
 369
 370 static struct obd_async_page_ops ll_async_page_ops = {
 371         .ap_make_ready =        ll_ap_make_ready,
 372         .ap_refresh_count =     ll_ap_refresh_count,
 373         .ap_fill_obdo =         ll_ap_fill_obdo,
 374         .ap_completion =        ll_ap_completion,
 375 };
 376
 377 struct ll_async_page *llap_cast_private(struct page *page)
 378 {
 379         struct ll_async_page *llap = (struct ll_async_page *)page->private;
 380
 381         LASSERTF(llap == NULL || llap->llap_magic == LLAP_MAGIC,
 382                  "page %p private %lu gave magic %d which != %d\n",
 383                  page, page->private, llap->llap_magic, LLAP_MAGIC);
 384
 385         return llap;
 386 }
 387
 388 /* Try to shrink the page cache for the @sbi filesystem by 1/@shrink_fraction.
 389  *
 390  * There is an llap attached onto every page in lustre, linked off @sbi.
 391  * We add an llap to the list so we don't lose our place during list walking.
 392  * If llaps in the list are being moved they will only move to the end
 393  * of the LRU, and we aren't terribly interested in those pages here (we
 394  * start at the beginning of the list where the least-used llaps are.
 395  */
 396 int llap_shrink_cache(struct ll_sb_info *sbi, int shrink_fraction)
 397 {
 398         struct ll_async_page *llap, dummy_llap = { .llap_magic = 0xd11ad11a };
 399         unsigned long total, want, count = 0;
 400
 401         total = sbi->ll_async_page_count;
 402
 403         /* There can be a large number of llaps (600k or more in a large
 404          * memory machine) so the VM 1/6 shrink ratio is likely too much.
 405          * Since we are freeing pages also, we don't necessarily want to
 406          * shrink so much.  Limit to 40MB of pages + llaps per call. */
 407         if (shrink_fraction == 0)
 408                 want = sbi->ll_async_page_count - sbi->ll_async_page_max + 32;
 409         else
 410                 want = (total + shrink_fraction - 1) / shrink_fraction;
 411
 412         if (want > 40 << (20 - PAGE_CACHE_SHIFT))
 413                 want = 40 << (20 - PAGE_CACHE_SHIFT);
 414
 415         CDEBUG(D_CACHE, "shrinking %lu of %lu pages (1/%d)\n",
 416                want, total, shrink_fraction);
 417
 418         spin_lock(&sbi->ll_lock);
 419         list_add(&dummy_llap.llap_pglist_item, &sbi->ll_pglist);
 420
 421         while (--total >= 0 && count < want) {
 422                 struct page *page;
 423                 int keep;
 424
 425                 if (unlikely(need_resched())) {
 426                         spin_unlock(&sbi->ll_lock);
 427                         cond_resched();
 428                         spin_lock(&sbi->ll_lock);
 429                 }
 430
 431                 llap = llite_pglist_next_llap(sbi,&dummy_llap.llap_pglist_item);
 432                 list_del_init(&dummy_llap.llap_pglist_item);
 433                 if (llap == NULL)
 434                         break;
 435
 436                 page = llap->llap_page;
 437                 LASSERT(page != NULL);
 438
 439                 list_add(&dummy_llap.llap_pglist_item, &llap->llap_pglist_item);
 440
 441                 /* Page needs/undergoing IO */
 442                 if (TryLockPage(page)) {
 443                         LL_CDEBUG_PAGE(D_PAGE, page, "can't lock\n");
 444                         continue;
 445                 }
 446
 447                 if (llap->llap_write_queued || PageDirty(page) ||
 448                     (!PageUptodate(page) &&
 449                      llap->llap_origin != LLAP_ORIGIN_READAHEAD))
 450                         keep = 1;
 451                 else
 452                         keep = 0;
 453
 454                 LL_CDEBUG_PAGE(D_PAGE, page,"%s LRU page: %s%s%s%s origin %s\n",
 455                                keep ? "keep" : "drop",
 456                                llap->llap_write_queued ? "wq " : "",
 457                                PageDirty(page) ? "pd " : "",
 458                                PageUptodate(page) ? "" : "!pu ",
 459                                llap->llap_defer_uptodate ? "" : "!du",
 460                                llap_origins[llap->llap_origin]);
 461
 462                 /* If page is dirty or undergoing IO don't discard it */
 463                 if (keep) {
 464                         unlock_page(page);
 465                         continue;
 466                 }
 467
 468                 page_cache_get(page);
 469                 spin_unlock(&sbi->ll_lock);
 470
 471                 ++count;
 472                 if (page->mapping != NULL) {
 473                         ll_ra_accounting(page, page->mapping);
 474                         ll_truncate_complete_page(page);
 475                 }
 476                 unlock_page(page);
 477                 page_cache_release(page);
 478
 479                 spin_lock(&sbi->ll_lock);
 480         }
 481         list_del(&dummy_llap.llap_pglist_item);
 482         spin_unlock(&sbi->ll_lock);
 483
 484         CDEBUG(D_CACHE, "shrank %lu/%lu and left %lu unscanned\n",
 485                count, want, total);
 486
 487         return count;
 488 }
 489
 490 struct ll_async_page *llap_from_page(struct page *page, unsigned origin)
 491 {
 492         struct ll_async_page *llap;
 493         struct obd_export *exp;
 494         struct inode *inode = page->mapping->host;
 495         struct ll_sb_info *sbi = ll_i2sbi(inode);
 496         int rc;
 497         ENTRY;
 498
 499         LASSERT(ll_async_page_slab);
 500         LASSERTF(origin < LLAP__ORIGIN_MAX, "%u\n", origin);
 501
 502         llap = llap_cast_private(page);
 503         if (llap != NULL) {
 504                 /* move to end of LRU list */
 505                 spin_lock(&sbi->ll_lock);
 506                 sbi->ll_pglist_gen++;
 507                 list_del_init(&llap->llap_pglist_item);
 508                 list_add_tail(&llap->llap_pglist_item, &sbi->ll_pglist);
 509                 spin_unlock(&sbi->ll_lock);
 510                 GOTO(out, llap);
 511         }
 512
 513         exp = ll_i2obdexp(page->mapping->host);
 514         if (exp == NULL)
 515                 RETURN(ERR_PTR(-EINVAL));
 516
 517         /* limit the number of lustre-cached pages */
 518         if (sbi->ll_async_page_count >= sbi->ll_async_page_max)
 519                 llap_shrink_cache(sbi, 0);
 520
 521         OBD_SLAB_ALLOC(llap, ll_async_page_slab, SLAB_KERNEL,
 522                        ll_async_page_slab_size);
 523         if (llap == NULL)
 524                 RETURN(ERR_PTR(-ENOMEM));
 525         llap->llap_magic = LLAP_MAGIC;
 526         llap->llap_cookie = (void *)llap + size_round(sizeof(*llap));
 527
 528         rc = obd_prep_async_page(exp, ll_i2info(inode)->lli_smd, NULL, page,
 529                                  (obd_off)page->index << PAGE_SHIFT,
 530                                  &ll_async_page_ops, llap, &llap->llap_cookie);
 531         if (rc) {
 532                 OBD_SLAB_FREE(llap, ll_async_page_slab,
 533                               ll_async_page_slab_size);
 534                 RETURN(ERR_PTR(rc));
 535         }
 536
 537         CDEBUG(D_CACHE, "llap %p page %p cookie %p obj off "LPU64"\n", llap,
 538                page, llap->llap_cookie, (obd_off)page->index << PAGE_SHIFT);
 539         /* also zeroing the PRIVBITS low order bitflags */
 540         __set_page_ll_data(page, llap);
 541         llap->llap_page = page;
 542
 543         spin_lock(&sbi->ll_lock);
 544         sbi->ll_pglist_gen++;
 545         sbi->ll_async_page_count++;
 546         list_add_tail(&llap->llap_pglist_item, &sbi->ll_pglist);
 547         spin_unlock(&sbi->ll_lock);
 548
 549  out:
 550         if (unlikely(sbi->ll_flags & LL_SBI_CHECKSUM)) {
 551                 __u32 csum = 0;
 552                 csum = crc32_le(csum, kmap(page), PAGE_SIZE);
 553                 kunmap(page);
 554                 if (origin == LLAP_ORIGIN_READAHEAD ||
 555                     origin == LLAP_ORIGIN_READPAGE) {
 556                         llap->llap_checksum = 0;
 557                 } else if (origin == LLAP_ORIGIN_COMMIT_WRITE ||
 558                            llap->llap_checksum == 0) {
 559                         llap->llap_checksum = csum;
 560                         CDEBUG(D_PAGE, "page %p cksum %x\n", page, csum);
 561                 } else if (llap->llap_checksum == csum) {
 562                         /* origin == LLAP_ORIGIN_WRITEPAGE */
 563                         CDEBUG(D_PAGE, "page %p cksum %x confirmed\n",
 564                                page, csum);
 565                 } else {
 566                         /* origin == LLAP_ORIGIN_WRITEPAGE */
 567                         LL_CDEBUG_PAGE(D_ERROR, page, "old cksum %x != new "
 568                                        "%x!\n", llap->llap_checksum, csum);
 569                 }
 570         }
 571
 572         llap->llap_origin = origin;
 573         RETURN(llap);
 574 }
 575
 576 static int queue_or_sync_write(struct obd_export *exp, struct inode *inode,
 577                                struct ll_async_page *llap,
 578                                unsigned to, obd_flag async_flags)
 579 {
 580         unsigned long size_index = inode->i_size >> PAGE_SHIFT;
 581         struct obd_io_group *oig;
 582         struct ll_sb_info *sbi = ll_i2sbi(inode);
 583         int rc, noquot = capable(CAP_SYS_RESOURCE) ? OBD_BRW_NOQUOTA : 0;
 584         ENTRY;
 585
 586         /* _make_ready only sees llap once we've unlocked the page */
 587         llap->llap_write_queued = 1;
 588         rc = obd_queue_async_io(exp, ll_i2info(inode)->lli_smd, NULL,
 589                                 llap->llap_cookie, OBD_BRW_WRITE | noquot,
 590                                 0, 0, 0, async_flags);
 591         if (rc == 0) {
 592                 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page, "write queued\n");
 593                 //llap_write_pending(inode, llap);
 594                 GOTO(out, 0);
 595         }
 596
 597         llap->llap_write_queued = 0;
 598
 599         rc = oig_init(&oig);
 600         if (rc)
 601                 GOTO(out, rc);
 602
 603         /* make full-page requests if we are not at EOF (bug 4410) */
 604         if (to != PAGE_SIZE && llap->llap_page->index < size_index) {
 605                 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page,
 606                                "sync write before EOF: size_index %lu, to %d\n",
 607                                size_index, to);
 608                 to = PAGE_SIZE;
 609         } else if (to != PAGE_SIZE && llap->llap_page->index == size_index) {
 610                 int size_to = inode->i_size & ~PAGE_MASK;
 611                 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page,
 612                                "sync write at EOF: size_index %lu, to %d/%d\n",
 613                                size_index, to, size_to);
 614                 if (to < size_to)
 615                         to = size_to;
 616         }
 617
 618         /* compare the checksum once before the page leaves llite */
 619         if (unlikely((sbi->ll_flags & LL_SBI_CHECKSUM) &&
 620                      llap->llap_checksum != 0)) {
 621                 __u32 csum = 0;
 622                 struct page *page = llap->llap_page;
 623                 csum = crc32_le(csum, kmap(page), PAGE_SIZE);
 624                 kunmap(page);
 625                 if (llap->llap_checksum == csum) {
 626                         CDEBUG(D_PAGE, "page %p cksum %x confirmed\n",
 627                                page, csum);
 628                 } else {
 629                         CERROR("page %p old cksum %x != new cksum %x!\n",
 630                                page, llap->llap_checksum, csum);
 631                 }
 632         }
 633
 634         rc = obd_queue_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig,
 635                                 llap->llap_cookie, OBD_BRW_WRITE | noquot,
 636                                 0, to, 0, ASYNC_READY | ASYNC_URGENT |
 637                                 ASYNC_COUNT_STABLE | ASYNC_GROUP_SYNC);
 638         if (rc)
 639                 GOTO(free_oig, rc);
 640
 641         rc = obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig);
 642         if (rc)
 643                 GOTO(free_oig, rc);
 644
 645         rc = oig_wait(oig);
 646
 647         if (!rc && async_flags & ASYNC_READY)
 648                 unlock_page(llap->llap_page);
 649
 650         LL_CDEBUG_PAGE(D_PAGE, llap->llap_page, "sync write returned %d\n", rc);
 651
 652 free_oig:
 653         oig_release(oig);
 654 out:
 655         RETURN(rc);
 656 }
 657
 658 /* update our write count to account for i_size increases that may have
 659  * happened since we've queued the page for io. */
 660
 661 /* be careful not to return success without setting the page Uptodate or
 662  * the next pass through prepare_write will read in stale data from disk. */
 663 int ll_commit_write(struct file *file, struct page *page, unsigned from,
 664                     unsigned to)
 665 {
 666         struct inode *inode = page->mapping->host;
 667         struct ll_inode_info *lli = ll_i2info(inode);
 668         struct lov_stripe_md *lsm = lli->lli_smd;
 669         struct obd_export *exp;
 670         struct ll_async_page *llap;
 671         loff_t size;
 672         int rc = 0;
 673         ENTRY;
 674
 675         SIGNAL_MASK_ASSERT(); /* XXX BUG 1511 */
 676         LASSERT(inode == file->f_dentry->d_inode);
 677         LASSERT(PageLocked(page));
 678
 679         CDEBUG(D_INODE, "inode %p is writing page %p from %d to %d at %lu\n",
 680                inode, page, from, to, page->index);
 681
 682         llap = llap_from_page(page, LLAP_ORIGIN_COMMIT_WRITE);
 683         if (IS_ERR(llap))
 684                 RETURN(PTR_ERR(llap));
 685
 686         exp = ll_i2obdexp(inode);
 687         if (exp == NULL)
 688                 RETURN(-EINVAL);
 689
 690         /* queue a write for some time in the future the first time we
 691          * dirty the page */
 692         if (!PageDirty(page)) {
 693                 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
 694                                      LPROC_LL_DIRTY_MISSES);
 695
 696                 rc = queue_or_sync_write(exp, inode, llap, to, 0);
 697                 if (rc)
 698                         GOTO(out, rc);
 699         } else {
 700                 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
 701                                      LPROC_LL_DIRTY_HITS);
 702         }
 703
 704         /* put the page in the page cache, from now on ll_removepage is
 705          * responsible for cleaning up the llap.
 706          * only set page dirty when it's queued to be write out */
 707         if (llap->llap_write_queued)
 708                 set_page_dirty(page);
 709
 710 out:
 711         size = (((obd_off)page->index) << PAGE_SHIFT) + to;
 712         down(&lli->lli_size_sem);
 713         if (rc == 0) {
 714                 obd_adjust_kms(exp, lsm, size, 0);
 715                 if (size > inode->i_size)
 716                         inode->i_size = size;
 717                 SetPageUptodate(page);
 718         } else if (size > inode->i_size) {
 719                 /* this page beyond the pales of i_size, so it can't be
 720                  * truncated in ll_p_r_e during lock revoking. we must
 721                  * teardown our book-keeping here. */
 722                 ll_removepage(page);
 723         }
 724         up(&lli->lli_size_sem);
 725         RETURN(rc);
 726 }
 727
 728 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi, unsigned long len)
 729 {
 730         struct ll_ra_info *ra = &sbi->ll_ra_info;
 731         unsigned long ret;
 732         ENTRY;
 733
 734         spin_lock(&sbi->ll_lock);
 735         ret = min(ra->ra_max_pages - ra->ra_cur_pages, len);
 736         ra->ra_cur_pages += ret;
 737         spin_unlock(&sbi->ll_lock);
 738
 739         RETURN(ret);
 740 }
 741
 742 static void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
 743 {
 744         struct ll_ra_info *ra = &sbi->ll_ra_info;
 745         spin_lock(&sbi->ll_lock);
 746         LASSERTF(ra->ra_cur_pages >= len, "r_c_p %lu len %lu\n",
 747                  ra->ra_cur_pages, len);
 748         ra->ra_cur_pages -= len;
 749         spin_unlock(&sbi->ll_lock);
 750 }
 751
 752 /* called for each page in a completed rpc.*/
 753 void ll_ap_completion(void *data, int cmd, struct obdo *oa, int rc)
 754 {
 755         struct ll_async_page *llap;
 756         struct page *page;
 757         ENTRY;
 758
 759         llap = LLAP_FROM_COOKIE(data);
 760         page = llap->llap_page;
 761         LASSERT(PageLocked(page));
 762
 763         LL_CDEBUG_PAGE(D_PAGE, page, "completing cmd %d with %d\n", cmd, rc);
 764
 765         if (cmd & OBD_BRW_READ && llap->llap_defer_uptodate)
 766                 ll_ra_count_put(ll_i2sbi(page->mapping->host), 1);
 767
 768         if (rc == 0)  {
 769                 if (cmd & OBD_BRW_READ) {
 770                         if (!llap->llap_defer_uptodate)
 771                                 SetPageUptodate(page);
 772                 } else {
 773                         llap->llap_write_queued = 0;
 774                 }
 775                 ClearPageError(page);
 776         } else {
 777                 if (cmd & OBD_BRW_READ) {
 778                         llap->llap_defer_uptodate = 0;
 779                 } else {
 780                         ll_redirty_page(page);
 781                 }
 782                 SetPageError(page);
 783         }
 784
 785         unlock_page(page);
 786
 787         if (0 && cmd & OBD_BRW_WRITE) {
 788                 llap_write_complete(page->mapping->host, llap);
 789                 ll_try_done_writing(page->mapping->host);
 790         }
 791
 792         if (PageWriteback(page)) {
 793                 end_page_writeback(page);
 794         }
 795         page_cache_release(page);
 796         EXIT;
 797 }
 798
 799 /* the kernel calls us here when a page is unhashed from the page cache.
 800  * the page will be locked and the kernel is holding a spinlock, so
 801  * we need to be careful.  we're just tearing down our book-keeping
 802  * here. */
 803 void ll_removepage(struct page *page)
 804 {
 805         struct inode *inode = page->mapping->host;
 806         struct obd_export *exp;
 807         struct ll_async_page *llap;
 808         struct ll_sb_info *sbi = ll_i2sbi(inode);
 809         int rc;
 810         ENTRY;
 811
 812         LASSERT(!in_interrupt());
 813
 814         /* sync pages or failed read pages can leave pages in the page
 815          * cache that don't have our data associated with them anymore */
 816         if (page->private == 0) {
 817                 EXIT;
 818                 return;
 819         }
 820
 821         LL_CDEBUG_PAGE(D_PAGE, page, "being evicted\n");
 822
 823         exp = ll_i2obdexp(inode);
 824         if (exp == NULL) {
 825                 CERROR("page %p ind %lu gave null export\n", page, page->index);
 826                 EXIT;
 827                 return;
 828         }
 829
 830         llap = llap_from_page(page, 0);
 831         if (IS_ERR(llap)) {
 832                 CERROR("page %p ind %lu couldn't find llap: %ld\n", page,
 833                        page->index, PTR_ERR(llap));
 834                 EXIT;
 835                 return;
 836         }
 837
 838         //llap_write_complete(inode, llap);
 839         rc = obd_teardown_async_page(exp, ll_i2info(inode)->lli_smd, NULL,
 840                                      llap->llap_cookie);
 841         if (rc != 0)
 842                 CERROR("page %p ind %lu failed: %d\n", page, page->index, rc);
 843
 844         /* this unconditional free is only safe because the page lock
 845          * is providing exclusivity to memory pressure/truncate/writeback..*/
 846         __clear_page_ll_data(page);
 847
 848         spin_lock(&sbi->ll_lock);
 849         if (!list_empty(&llap->llap_pglist_item))
 850                 list_del_init(&llap->llap_pglist_item);
 851         sbi->ll_pglist_gen++;
 852         sbi->ll_async_page_count--;
 853         spin_unlock(&sbi->ll_lock);
 854         OBD_SLAB_FREE(llap, ll_async_page_slab, ll_async_page_slab_size);
 855         EXIT;
 856 }
 857
 858 static int ll_page_matches(struct page *page, int fd_flags)
 859 {
 860         struct lustre_handle match_lockh = {0};
 861         struct inode *inode = page->mapping->host;
 862         ldlm_policy_data_t page_extent;
 863         int flags, matches;
 864         ENTRY;
 865
 866         if (unlikely(fd_flags & LL_FILE_GROUP_LOCKED))
 867                 RETURN(1);
 868
 869         page_extent.l_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
 870         page_extent.l_extent.end =
 871                 page_extent.l_extent.start + PAGE_CACHE_SIZE - 1;
 872         flags = LDLM_FL_TEST_LOCK | LDLM_FL_BLOCK_GRANTED;
 873         if (!(fd_flags & LL_FILE_READAHEAD))
 874                 flags |= LDLM_FL_CBPENDING;
 875         matches = obd_match(ll_i2sbi(inode)->ll_osc_exp,
 876                             ll_i2info(inode)->lli_smd, LDLM_EXTENT,
 877                             &page_extent, LCK_PR | LCK_PW, &flags, inode,
 878                             &match_lockh);
 879         RETURN(matches);
 880 }
 881
 882 static int ll_issue_page_read(struct obd_export *exp,
 883                               struct ll_async_page *llap,
 884                               struct obd_io_group *oig, int defer)
 885 {
 886         struct page *page = llap->llap_page;
 887         int rc;
 888
 889         page_cache_get(page);
 890         llap->llap_defer_uptodate = defer;
 891         llap->llap_ra_used = 0;
 892         rc = obd_queue_group_io(exp, ll_i2info(page->mapping->host)->lli_smd,
 893                                 NULL, oig, llap->llap_cookie, OBD_BRW_READ, 0,
 894                                 PAGE_SIZE, 0, ASYNC_COUNT_STABLE | ASYNC_READY |
 895                                               ASYNC_URGENT);
 896         if (rc) {
 897                 LL_CDEBUG_PAGE(D_ERROR, page, "read queue failed: rc %d\n", rc);
 898                 page_cache_release(page);
 899         }
 900         RETURN(rc);
 901 }
 902
 903 static void ll_ra_stats_inc_unlocked(struct ll_ra_info *ra, enum ra_stat which)
 904 {
 905         LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
 906         ra->ra_stats[which]++;
 907 }
 908
 909 static void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
 910 {
 911         struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
 912         struct ll_ra_info *ra = &ll_i2sbi(mapping->host)->ll_ra_info;
 913
 914         spin_lock(&sbi->ll_lock);
 915         ll_ra_stats_inc_unlocked(ra, which);
 916         spin_unlock(&sbi->ll_lock);
 917 }
 918
 919 void ll_ra_accounting(struct page *page, struct address_space *mapping)
 920 {
 921         struct ll_async_page *llap;
 922
 923         llap = llap_from_page(page, LLAP_ORIGIN_WRITEPAGE);
 924         if (IS_ERR(llap))
 925                 return;
 926
 927         if (!llap->llap_defer_uptodate || llap->llap_ra_used)
 928                 return;
 929
 930         ll_ra_stats_inc(mapping, RA_STAT_DISCARDED);
 931 }
 932
 933 #define RAS_CDEBUG(ras) \
 934         CDEBUG(D_READA, "lrp %lu c %lu ws %lu wl %lu nra %lu\n",        \
 935                ras->ras_last_readpage, ras->ras_consecutive,            \
 936                ras->ras_window_start, ras->ras_window_len,              \
 937                ras->ras_next_readahead);
 938
 939 static int index_in_window(unsigned long index, unsigned long point,
 940                            unsigned long before, unsigned long after)
 941 {
 942         unsigned long start = point - before, end = point + after;
 943
 944         if (start > point)
 945                start = 0;
 946         if (end < point)
 947                end = ~0;
 948
 949         return start <= index && index <= end;
 950 }
 951
 952 static int ll_readahead(struct ll_readahead_state *ras,
 953                          struct obd_export *exp, struct address_space *mapping,
 954                          struct obd_io_group *oig, int flags)
 955 {
 956         unsigned long i, start = 0, end = 0, reserved;
 957         struct ll_async_page *llap;
 958         struct page *page;
 959         int rc, ret = 0, match_failed = 0;
 960         __u64 kms;
 961         unsigned int gfp_mask;
 962         ENTRY;
 963
 964         kms = lov_merge_size(ll_i2info(mapping->host)->lli_smd, 1);
 965         if (kms == 0) {
 966                 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
 967                 RETURN(0);
 968         }
 969
 970         spin_lock(&ras->ras_lock);
 971         /* reserve a part of the read-ahead window that we'll be issuing */
 972         if (ras->ras_window_len) {
 973                 start = ras->ras_next_readahead;
 974                 end = ras->ras_window_start + ras->ras_window_len - 1;
 975                 end = min(end, (unsigned long)((kms - 1) >> PAGE_CACHE_SHIFT));
 976                 ras->ras_next_readahead = max(end, end + 1);
 977
 978                 RAS_CDEBUG(ras);
 979         }
 980         spin_unlock(&ras->ras_lock);
 981
 982         if (end == 0) {
 983                 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
 984                 RETURN(0);
 985         }
 986
 987         reserved = ll_ra_count_get(ll_i2sbi(mapping->host), end - start + 1);
 988         if (reserved < end - start + 1)
 989                 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
 990
 991         gfp_mask = GFP_HIGHUSER & ~__GFP_WAIT;
 992 #ifdef __GFP_NOWARN
 993         gfp_mask |= __GFP_NOWARN;
 994 #endif
 995
 996         for (i = start; reserved > 0 && !match_failed && i <= end; i++) {
 997                 /* skip locked pages from previous readpage calls */
 998                 page = grab_cache_page_nowait_gfp(mapping, i, gfp_mask);
 999                 if (page == NULL) {
1000                         ll_ra_stats_inc(mapping, RA_STAT_FAILED_GRAB_PAGE);
1001                         CDEBUG(D_READA, "g_c_p_n failed\n");
1002                         continue;
1003                 }
1004
1005                 /* we do this first so that we can see the page in the /proc
1006                  * accounting */
1007                 llap = llap_from_page(page, LLAP_ORIGIN_READAHEAD);
1008                 if (IS_ERR(llap) || llap->llap_defer_uptodate)
1009                         goto next_page;
1010
1011                 /* skip completed pages */
1012                 if (Page_Uptodate(page))
1013                         goto next_page;
1014
1015                 /* bail when we hit the end of the lock. */
1016                 if ((rc = ll_page_matches(page, flags|LL_FILE_READAHEAD)) <= 0){
1017                         LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
1018                                        "lock match failed: rc %d\n", rc);
1019                         ll_ra_stats_inc(mapping, RA_STAT_FAILED_MATCH);
1020                         match_failed = 1;
1021                         goto next_page;
1022                 }
1023
1024                 rc = ll_issue_page_read(exp, llap, oig, 1);
1025                 if (rc == 0) {
1026                         reserved--;
1027                         ret++;
1028                         LL_CDEBUG_PAGE(D_READA| D_PAGE, page,
1029                                        "started read-ahead\n");
1030                 }
1031                 if (rc) {
1032         next_page:
1033                         LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
1034                                        "skipping read-ahead\n");
1035
1036                         unlock_page(page);
1037                 }
1038                 page_cache_release(page);
1039         }
1040
1041         LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
1042         if (reserved != 0)
1043                 ll_ra_count_put(ll_i2sbi(mapping->host), reserved);
1044         if (i == end + 1 && end == (kms >> PAGE_CACHE_SHIFT))
1045                 ll_ra_stats_inc(mapping, RA_STAT_EOF);
1046
1047         /* if we didn't get to the end of the region we reserved from
1048          * the ras we need to go back and update the ras so that the
1049          * next read-ahead tries from where we left off.  we only do so
1050          * if the region we failed to issue read-ahead on is still ahead
1051          * of the app and behind the next index to start read-ahead from */
1052         if (i != end + 1) {
1053                 spin_lock(&ras->ras_lock);
1054                 if (i < ras->ras_next_readahead &&
1055                     index_in_window(i, ras->ras_window_start, 0,
1056                                     ras->ras_window_len)) {
1057                         ras->ras_next_readahead = i;
1058                         RAS_CDEBUG(ras);
1059                 }
1060                 spin_unlock(&ras->ras_lock);
1061         }
1062
1063         RETURN(ret);
1064 }
1065
1066 static void ras_set_start(struct ll_readahead_state *ras, unsigned long index)
1067 {
1068         ras->ras_window_start = index & (~(PTLRPC_MAX_BRW_PAGES - 1));
1069 }
1070
1071 /* called with the ras_lock held or from places where it doesn't matter */
1072 static void ras_reset(struct ll_readahead_state *ras, unsigned long index)
1073 {
1074         ras->ras_last_readpage = index;
1075         ras->ras_consecutive = 1;
1076         ras->ras_window_len = 0;
1077         ras_set_start(ras, index);
1078         ras->ras_next_readahead = ras->ras_window_start;
1079
1080         RAS_CDEBUG(ras);
1081 }
1082
1083 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
1084 {
1085         spin_lock_init(&ras->ras_lock);
1086         ras_reset(ras, 0);
1087 }
1088
1089 static void ras_update(struct ll_sb_info *sbi, struct ll_readahead_state *ras,
1090                        unsigned long index, unsigned hit)
1091 {
1092         struct ll_ra_info *ra = &sbi->ll_ra_info;
1093         int zero = 0;
1094         ENTRY;
1095
1096         spin_lock(&sbi->ll_lock);
1097         spin_lock(&ras->ras_lock);
1098
1099         ll_ra_stats_inc_unlocked(ra, hit ? RA_STAT_HIT : RA_STAT_MISS);
1100
1101         /* reset the read-ahead window in two cases.  First when the app seeks
1102          * or reads to some other part of the file.  Secondly if we get a
1103          * read-ahead miss that we think we've previously issued.  This can
1104          * be a symptom of there being so many read-ahead pages that the VM is
1105          * reclaiming it before we get to it. */
1106         if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
1107                 zero = 1;
1108                 ll_ra_stats_inc_unlocked(ra, RA_STAT_DISTANT_READPAGE);
1109         } else if (!hit && ras->ras_window_len &&
1110                    index < ras->ras_next_readahead &&
1111                    index_in_window(index, ras->ras_window_start, 0,
1112                                    ras->ras_window_len)) {
1113                 zero = 1;
1114                 ll_ra_stats_inc_unlocked(ra, RA_STAT_MISS_IN_WINDOW);
1115         }
1116
1117         if (zero) {
1118                 ras_reset(ras, index);
1119                 GOTO(out_unlock, 0);
1120         }
1121
1122         ras->ras_last_readpage = index;
1123         ras->ras_consecutive++;
1124         ras_set_start(ras, index);
1125         ras->ras_next_readahead = max(ras->ras_window_start,
1126                                       ras->ras_next_readahead);
1127
1128         /* wait for a few pages to arrive before issuing readahead to avoid
1129          * the worst overutilization */
1130         if (ras->ras_consecutive == 3) {
1131                 ras->ras_window_len = PTLRPC_MAX_BRW_PAGES;
1132                 GOTO(out_unlock, 0);
1133         }
1134
1135         /* we need to increase the window sometimes.  we'll arbitrarily
1136          * do it half-way through the pages in an rpc */
1137         if ((index & (PTLRPC_MAX_BRW_PAGES - 1)) ==
1138             (PTLRPC_MAX_BRW_PAGES >> 1)) {
1139                 ras->ras_window_len += PTLRPC_MAX_BRW_PAGES;
1140                 ras->ras_window_len = min(ras->ras_window_len,
1141                                           ra->ra_max_pages);
1142         }
1143
1144         EXIT;
1145 out_unlock:
1146         RAS_CDEBUG(ras);
1147         spin_unlock(&ras->ras_lock);
1148         spin_unlock(&sbi->ll_lock);
1149         return;
1150 }
1151
1152 int ll_writepage(struct page *page)
1153 {
1154         struct inode *inode = page->mapping->host;
1155         struct ll_inode_info *lli = ll_i2info(inode);
1156         struct obd_export *exp;
1157         struct ll_async_page *llap;
1158         int rc = 0;
1159         ENTRY;
1160
1161         LASSERT(!PageDirty(page));
1162         LASSERT(PageLocked(page));
1163
1164         exp = ll_i2obdexp(inode);
1165         if (exp == NULL)
1166                 GOTO(out, rc = -EINVAL);
1167
1168         llap = llap_from_page(page, LLAP_ORIGIN_WRITEPAGE);
1169         if (IS_ERR(llap))
1170                 GOTO(out, rc = PTR_ERR(llap));
1171
1172         page_cache_get(page);
1173         if (llap->llap_write_queued) {
1174                 LL_CDEBUG_PAGE(D_PAGE, page, "marking urgent\n");
1175                 rc = obd_set_async_flags(exp, lli->lli_smd, NULL,
1176                                          llap->llap_cookie,
1177                                          ASYNC_READY | ASYNC_URGENT);
1178         } else {
1179                 rc = queue_or_sync_write(exp, inode, llap, PAGE_SIZE,
1180                                          ASYNC_READY | ASYNC_URGENT);
1181         }
1182         if (rc)
1183                 page_cache_release(page);
1184 out:
1185         if (rc) {
1186                 if (!lli->lli_async_rc)
1187                         lli->lli_async_rc = rc;
1188                 /* re-dirty page on error so it retries write */
1189                 ll_redirty_page(page);
1190                 unlock_page(page);
1191         }
1192         RETURN(rc);
1193 }
1194
1195 /*
1196  * for now we do our readpage the same on both 2.4 and 2.5.  The kernel's
1197  * read-ahead assumes it is valid to issue readpage all the way up to
1198  * i_size, but our dlm locks make that not the case.  We disable the
1199  * kernel's read-ahead and do our own by walking ahead in the page cache
1200  * checking for dlm lock coverage.  the main difference between 2.4 and
1201  * 2.6 is how read-ahead gets batched and issued, but we're using our own,
1202  * so they look the same.
1203  */
1204 int ll_readpage(struct file *filp, struct page *page)
1205 {
1206         struct ll_file_data *fd = LUSTRE_FPRIVATE(filp);
1207         struct inode *inode = page->mapping->host;
1208         struct obd_export *exp;
1209         struct ll_async_page *llap;
1210         struct obd_io_group *oig = NULL;
1211         int rc;
1212         ENTRY;
1213
1214         LASSERT(PageLocked(page));
1215         LASSERT(!PageUptodate(page));
1216         CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p),offset=%Lu=%#Lx\n",
1217                inode->i_ino, inode->i_generation, inode,
1218                (((loff_t)page->index) << PAGE_SHIFT),
1219                (((loff_t)page->index) << PAGE_SHIFT));
1220         LASSERT(atomic_read(&filp->f_dentry->d_inode->i_count) > 0);
1221
1222         rc = oig_init(&oig);
1223         if (rc < 0)
1224                 GOTO(out, rc);
1225
1226         exp = ll_i2obdexp(inode);
1227         if (exp == NULL)
1228                 GOTO(out, rc = -EINVAL);
1229
1230         llap = llap_from_page(page, LLAP_ORIGIN_READPAGE);
1231         if (IS_ERR(llap))
1232                 GOTO(out, rc = PTR_ERR(llap));
1233
1234         if (ll_i2sbi(inode)->ll_ra_info.ra_max_pages)
1235                 ras_update(ll_i2sbi(inode), &fd->fd_ras, page->index,
1236                            llap->llap_defer_uptodate);
1237
1238         if (llap->llap_defer_uptodate) {
1239                 llap->llap_ra_used = 1;
1240                 rc = ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1241                                   fd->fd_flags);
1242                 if (rc > 0)
1243                         obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd,
1244                                              NULL, oig);
1245                 LL_CDEBUG_PAGE(D_PAGE, page, "marking uptodate from defer\n");
1246                 SetPageUptodate(page);
1247                 unlock_page(page);
1248                 GOTO(out_oig, rc = 0);
1249         }
1250
1251         rc = ll_page_matches(page, fd->fd_flags);
1252         if (rc < 0) {
1253                 LL_CDEBUG_PAGE(D_ERROR, page, "lock match failed: rc %d\n", rc);
1254                 GOTO(out, rc);
1255         }
1256
1257         if (rc == 0) {
1258                 CWARN("ino %lu page %lu (%llu) not covered by "
1259                       "a lock (mmap?).  check debug logs.\n",
1260                       inode->i_ino, page->index,
1261                       (long long)page->index << PAGE_CACHE_SHIFT);
1262         }
1263
1264         rc = ll_issue_page_read(exp, llap, oig, 0);
1265         if (rc)
1266                 GOTO(out, rc);
1267
1268         LL_CDEBUG_PAGE(D_PAGE, page, "queued readpage\n");
1269         if (ll_i2sbi(inode)->ll_ra_info.ra_max_pages)
1270                 ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1271                              fd->fd_flags);
1272
1273         rc = obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig);
1274
1275 out:
1276         if (rc)
1277                 unlock_page(page);
1278 out_oig:
1279         if (oig != NULL)
1280                 oig_release(oig);
1281         RETURN(rc);
1282 }