1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Lustre Lite I/O page cache routines shared by different kernel revs
6 * Copyright (c) 2001-2003 Cluster File Systems, Inc.
8 * This file is part of Lustre, http://www.lustre.org.
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.
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.
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.
24 #include <linux/config.h>
25 #include <linux/kernel.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>
37 #include <linux/stat.h>
38 #include <asm/uaccess.h>
39 #include <asm/segment.h>
41 #include <linux/pagemap.h>
42 #include <linux/smp_lock.h>
44 #define DEBUG_SUBSYSTEM S_LLITE
46 #include <linux/lustre_mds.h>
47 #include <linux/lustre_lite.h>
48 #include "llite_internal.h"
49 #include <linux/lustre_compat25.h>
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 )
57 /* SYNCHRONOUS I/O to object storage for an inode */
58 static int ll_brw(int cmd, struct inode *inode, struct obdo *oa,
59 struct page *page, int flags)
61 struct ll_inode_info *lli = ll_i2info(inode);
62 struct lov_stripe_md *lsm = lli->lli_smd;
68 do_gettimeofday(&start);
71 pg.disk_offset = pg.page_offset = ((obd_off)page->index) << PAGE_SHIFT;
73 if (cmd == OBD_BRW_WRITE &&
74 (pg.disk_offset + PAGE_SIZE > inode->i_size))
75 pg.count = inode->i_size % PAGE_SIZE;
79 CDEBUG(D_PAGE, "%s %d bytes ino %lu at "LPU64"/"LPX64"\n",
80 cmd & OBD_BRW_WRITE ? "write" : "read", pg.count, inode->i_ino,
81 pg.disk_offset, pg.disk_offset);
83 CERROR("ZERO COUNT: ino %lu: size %p:%Lu(%p:%Lu) idx %lu off "
84 LPU64"\n", inode->i_ino, inode, inode->i_size,
85 page->mapping->host, page->mapping->host->i_size,
86 page->index, pg.disk_offset);
91 if (cmd == OBD_BRW_WRITE)
92 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
93 LPROC_LL_BRW_WRITE, pg.count);
95 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
96 LPROC_LL_BRW_READ, pg.count);
97 rc = obd_brw(cmd, ll_i2dtexp(inode), oa, lsm, 1, &pg, NULL);
99 obdo_to_inode(inode, oa, OBD_MD_FLBLOCKS);
101 CERROR("error from obd_brw: rc = %d\n", rc);
102 ll_stime_record(ll_i2sbi(inode), &start,
103 &ll_i2sbi(inode)->ll_brw_stime);
107 /* this isn't where truncate starts. roughly:
108 * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate
109 * we grab the lock back in setattr_raw to avoid races. */
110 void ll_truncate(struct inode *inode)
112 struct lov_stripe_md *lsm = ll_i2info(inode)->lli_smd;
113 struct obdo *oa = NULL;
117 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p)\n", inode->i_ino,
118 inode->i_generation, inode);
121 CDEBUG(D_INODE, "truncate on inode %lu with no objects\n",
129 CERROR("cannot alloc oa, error %d\n",
135 oa->o_id = lsm->lsm_object_id;
136 oa->o_gr = lsm->lsm_object_gr;
137 oa->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP;
138 obdo_from_inode(oa, inode, OBD_MD_FLTYPE | OBD_MD_FLMODE |
139 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
141 CDEBUG(D_INFO, "calling punch for "LPX64" (all bytes after %Lu)\n",
142 oa->o_id, inode->i_size);
144 /* truncate == punch from new size to absolute end of file */
145 /* NB: obd_punch must be called with i_sem held! It updates the kms! */
146 rc = obd_punch(ll_i2dtexp(inode), oa, lsm, inode->i_size,
147 OBD_OBJECT_EOF, NULL);
149 CERROR("obd_truncate fails (%d) ino %lu\n", rc, inode->i_ino);
151 obdo_to_inode(inode, oa, OBD_MD_FLSIZE | OBD_MD_FLBLOCKS |
152 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
159 __u64 lov_merge_size(struct lov_stripe_md *lsm, int kms);
160 int ll_prepare_write(struct file *file, struct page *page, unsigned from,
163 struct inode *inode = page->mapping->host;
164 struct ll_inode_info *lli = ll_i2info(inode);
165 struct lov_stripe_md *lsm = lli->lli_smd;
166 obd_off offset = ((obd_off)page->index) << PAGE_SHIFT;
167 struct obdo *oa = NULL;
173 LASSERT(PageLocked(page));
174 (void)llap_cast_private(page); /* assertion */
176 /* Check to see if we should return -EIO right away */
178 pga.disk_offset = pga.page_offset = offset;
179 pga.count = PAGE_SIZE;
186 oa->o_id = lsm->lsm_object_id;
187 oa->o_gr = lsm->lsm_object_gr;
188 oa->o_mode = inode->i_mode;
189 oa->o_valid = OBD_MD_FLID | OBD_MD_FLMODE |
190 OBD_MD_FLTYPE | OBD_MD_FLGROUP;
192 rc = obd_brw(OBD_BRW_CHECK, ll_i2dtexp(inode), oa, lsm,
195 GOTO(out_free_oa, rc);
197 if (PageUptodate(page))
198 GOTO(out_free_oa, 0);
200 /* We're completely overwriting an existing page, so _don't_ set it up
201 * to date until commit_write */
202 if (from == 0 && to == PAGE_SIZE) {
203 POISON_PAGE(page, 0x11);
204 GOTO(out_free_oa, 0);
207 /* If are writing to a new page, no need to read old data. The extent
208 * locking will have updated the KMS, and for our purposes here we can
209 * treat it like i_size. */
210 kms = lov_merge_size(lsm, 1);
212 memset(kmap(page), 0, PAGE_SIZE);
214 GOTO(prepare_done, rc = 0);
217 /* XXX could be an async ocp read.. read-ahead? */
218 rc = ll_brw(OBD_BRW_READ, inode, oa, page, 0);
220 /* bug 1598: don't clobber blksize */
221 oa->o_valid &= ~(OBD_MD_FLSIZE | OBD_MD_FLBLKSZ);
222 obdo_refresh_inode(inode, oa, oa->o_valid);
228 SetPageUptodate(page);
234 struct ll_async_page *llap_from_cookie(void *cookie)
236 struct ll_async_page *llap = cookie;
237 if (llap->llap_magic != LLAP_MAGIC)
238 return ERR_PTR(-EINVAL);
242 static int ll_ap_make_ready(void *data, int cmd)
244 struct ll_async_page *llap;
248 llap = llap_from_cookie(data);
252 page = llap->llap_page;
254 LASSERT(cmd != OBD_BRW_READ);
256 /* we're trying to write, but the page is locked.. come back later */
257 if (TryLockPage(page))
260 LL_CDEBUG_PAGE(D_PAGE, page, "made ready\n");
261 page_cache_get(page);
263 /* if we left PageDirty we might get another writepage call
264 * in the future. list walkers are bright enough
265 * to check page dirty so we can leave it on whatever list
266 * its on. XXX also, we're called with the cli list so if
267 * we got the page cache list we'd create a lock inversion
268 * with the removepage path which gets the page lock then the
270 clear_page_dirty(page);
274 /* We have two reasons for giving llite the opportunity to change the
275 * write length of a given queued page as it builds the RPC containing
278 * 1) Further extending writes may have landed in the page cache
279 * since a partial write first queued this page requiring us
280 * to write more from the page cache.
281 * 2) We might have raced with truncate and want to avoid performing
282 * write RPCs that are just going to be thrown away by the
283 * truncate's punch on the storage targets.
285 * The kms serves these purposes as it is set at both truncate and extending
288 static int ll_ap_refresh_count(void *data, int cmd)
290 struct ll_async_page *llap;
291 struct lov_stripe_md *lsm;
296 /* readpage queues with _COUNT_STABLE, shouldn't get here. */
297 LASSERT(cmd != OBD_BRW_READ);
299 llap = llap_from_cookie(data);
301 RETURN(PTR_ERR(llap));
303 page = llap->llap_page;
304 lsm = ll_i2info(page->mapping->host)->lli_smd;
305 kms = lov_merge_size(lsm, 1);
307 /* catch race with truncate */
308 if (((__u64)page->index << PAGE_SHIFT) >= kms)
311 /* catch sub-page write at end of file */
312 if (((__u64)page->index << PAGE_SHIFT) + PAGE_SIZE > kms)
313 return kms % PAGE_SIZE;
318 void ll_inode_fill_obdo(struct inode *inode, int cmd, struct obdo *oa)
320 struct lov_stripe_md *lsm;
321 obd_valid valid_flags;
323 lsm = ll_i2info(inode)->lli_smd;
325 oa->o_id = lsm->lsm_object_id;
326 oa->o_gr = lsm->lsm_object_gr;
327 oa->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP;
328 valid_flags = OBD_MD_FLTYPE | OBD_MD_FLATIME;
329 if (cmd == OBD_BRW_WRITE) {
330 oa->o_valid |= OBD_MD_FLIFID | OBD_MD_FLEPOCH;
331 mdc_pack_id(obdo_id(oa), inode->i_ino, 0, inode->i_mode,
332 id_group(&ll_i2info(inode)->lli_id),
333 id_fid(&ll_i2info(inode)->lli_id));
335 oa->o_easize = ll_i2info(inode)->lli_io_epoch;
336 valid_flags |= OBD_MD_FLMTIME | OBD_MD_FLCTIME;
339 obdo_from_inode(oa, inode, valid_flags);
342 static void ll_ap_fill_obdo(void *data, int cmd, struct obdo *oa)
344 struct ll_async_page *llap;
347 llap = llap_from_cookie(data);
353 ll_inode_fill_obdo(llap->llap_page->mapping->host, cmd, oa);
357 static struct obd_async_page_ops ll_async_page_ops = {
358 .ap_make_ready = ll_ap_make_ready,
359 .ap_refresh_count = ll_ap_refresh_count,
360 .ap_fill_obdo = ll_ap_fill_obdo,
361 .ap_completion = ll_ap_completion,
364 struct ll_async_page *llap_cast_private(struct page *page)
366 struct ll_async_page *llap = (struct ll_async_page *)page->private;
368 LASSERTF(llap == NULL || llap->llap_magic == LLAP_MAGIC,
369 "page %p private %lu gave magic %d which != %d\n",
370 page, page->private, llap->llap_magic, LLAP_MAGIC);
375 /* XXX have the exp be an argument? */
376 struct ll_async_page *llap_from_page(struct page *page)
378 struct ll_async_page *llap;
379 struct obd_export *exp;
380 struct inode *inode = page->mapping->host;
381 struct ll_sb_info *sbi = ll_i2sbi(inode);
385 llap = llap_cast_private(page);
389 exp = ll_i2dtexp(page->mapping->host);
391 RETURN(ERR_PTR(-EINVAL));
393 OBD_ALLOC(llap, sizeof(*llap));
395 RETURN(ERR_PTR(-ENOMEM));
396 llap->llap_magic = LLAP_MAGIC;
397 rc = obd_prep_async_page(exp, ll_i2info(inode)->lli_smd, NULL, page,
398 (obd_off)page->index << PAGE_SHIFT,
399 &ll_async_page_ops, llap, &llap->llap_cookie);
401 OBD_FREE(llap, sizeof(*llap));
405 CDEBUG(D_CACHE, "llap %p page %p cookie %p obj off "LPU64"\n", llap,
406 page, llap->llap_cookie, (obd_off)page->index << PAGE_SHIFT);
407 /* also zeroing the PRIVBITS low order bitflags */
408 __set_page_ll_data(page, llap);
409 llap->llap_page = page;
411 spin_lock(&sbi->ll_lock);
412 sbi->ll_pglist_gen++;
413 list_add_tail(&llap->llap_proc_item, &sbi->ll_pglist);
414 spin_unlock(&sbi->ll_lock);
419 static int queue_or_sync_write(struct obd_export *exp,
420 struct lov_stripe_md *lsm,
421 struct ll_async_page *llap,
423 obd_flags async_flags)
425 struct obd_io_group *oig;
429 /* _make_ready only sees llap once we've unlocked the page */
430 llap->llap_write_queued = 1;
431 rc = obd_queue_async_io(exp, lsm, NULL, llap->llap_cookie,
432 OBD_BRW_WRITE, 0, 0, 0, async_flags);
434 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page, "write queued\n");
435 //llap_write_pending(inode, llap);
439 llap->llap_write_queued = 0;
445 rc = obd_queue_group_io(exp, lsm, NULL, oig, llap->llap_cookie,
446 OBD_BRW_WRITE, 0, to, 0, ASYNC_READY |
447 ASYNC_URGENT | ASYNC_COUNT_STABLE |
452 rc = obd_trigger_group_io(exp, lsm, NULL, oig);
458 if (!rc && async_flags & ASYNC_READY)
459 unlock_page(llap->llap_page);
461 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page,
462 "sync write returned %d\n", rc);
471 void lov_increase_kms(struct obd_export *exp, struct lov_stripe_md *lsm,
474 /* be careful not to return success without setting the page Uptodate or
475 * the next pass through prepare_write will read in stale data from disk. */
476 int ll_commit_write(struct file *file, struct page *page, unsigned from,
479 struct inode *inode = page->mapping->host;
480 struct ll_inode_info *lli = ll_i2info(inode);
481 struct lov_stripe_md *lsm = lli->lli_smd;
482 struct obd_export *exp = NULL;
483 struct ll_async_page *llap;
488 SIGNAL_MASK_ASSERT(); /* XXX BUG 1511 */
489 LASSERT(inode == file->f_dentry->d_inode);
490 LASSERT(PageLocked(page));
492 CDEBUG(D_INODE, "inode %p is writing page %p from %d to %d at %lu\n",
493 inode, page, from, to, page->index);
495 llap = llap_from_page(page);
497 RETURN(PTR_ERR(llap));
499 /* queue a write for some time in the future the first time we
501 if (!PageDirty(page)) {
502 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
503 LPROC_LL_DIRTY_MISSES);
505 exp = ll_i2dtexp(inode);
509 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd, llap,
514 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
515 LPROC_LL_DIRTY_HITS);
518 /* put the page in the page cache, from now on ll_removepage is
519 * responsible for cleaning up the llap.
520 * don't dirty the page if it has been write out in q_o_s_w */
521 if (llap->llap_write_queued)
522 set_page_dirty(page);
526 size = (((obd_off)page->index) << PAGE_SHIFT) + to;
527 lov_increase_kms(exp, lsm, size);
528 if (size > inode->i_size)
529 inode->i_size = size;
530 SetPageUptodate(page);
535 int ll_writepage(struct page *page)
537 struct inode *inode = page->mapping->host;
538 struct obd_export *exp;
539 struct ll_async_page *llap;
543 LASSERT(!PageDirty(page));
544 LASSERT(PageLocked(page));
546 exp = ll_i2dtexp(inode);
548 GOTO(out, rc = -EINVAL);
550 llap = llap_from_page(page);
552 GOTO(out, rc = PTR_ERR(llap));
554 page_cache_get(page);
555 if (llap->llap_write_queued) {
556 LL_CDEBUG_PAGE(D_PAGE, page, "marking urgent\n");
557 rc = obd_set_async_flags(exp, ll_i2info(inode)->lli_smd, NULL,
559 ASYNC_READY | ASYNC_URGENT);
561 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd, llap,
562 PAGE_SIZE, ASYNC_READY |
566 page_cache_release(page);
575 ll_ra_count_get(struct ll_sb_info *sbi, unsigned long len)
577 struct ll_ra_info *ra = &sbi->ll_ra_info;
581 spin_lock(&sbi->ll_lock);
582 ret = min(ra->ra_max_pages - ra->ra_cur_pages, len);
583 ra->ra_cur_pages += ret;
584 spin_unlock(&sbi->ll_lock);
589 static void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
591 struct ll_ra_info *ra = &sbi->ll_ra_info;
592 spin_lock(&sbi->ll_lock);
593 LASSERTF(ra->ra_cur_pages >= len, "r_c_p %lu len %lu\n",
594 ra->ra_cur_pages, len);
595 ra->ra_cur_pages -= len;
596 spin_unlock(&sbi->ll_lock);
599 /* called for each page in a completed rpc.*/
600 void ll_ap_completion(void *data, int cmd, struct obdo *oa, int rc)
602 struct ll_async_page *llap;
606 llap = llap_from_cookie(data);
612 page = llap->llap_page;
613 LASSERT(PageLocked(page));
615 LL_CDEBUG_PAGE(D_PAGE, page, "completing cmd %d with %d\n", cmd, rc);
617 if (cmd == OBD_BRW_READ && llap->llap_defer_uptodate)
618 ll_ra_count_put(ll_i2sbi(page->mapping->host), 1);
621 if (cmd == OBD_BRW_READ) {
622 if (!llap->llap_defer_uptodate)
623 SetPageUptodate(page);
625 llap->llap_write_queued = 0;
627 ClearPageError(page);
629 if (cmd == OBD_BRW_READ)
630 llap->llap_defer_uptodate = 0;
636 if (0 && cmd == OBD_BRW_WRITE) {
637 llap_write_complete(page->mapping->host, llap);
638 ll_try_done_writing(page->mapping->host);
641 if (PageWriteback(page)) {
642 end_page_writeback(page);
644 page_cache_release(page);
648 /* the kernel calls us here when a page is unhashed from the page cache.
649 * the page will be locked and the kernel is holding a spinlock, so
650 * we need to be careful. we're just tearing down our book-keeping
652 void ll_removepage(struct page *page)
654 struct inode *inode = page->mapping->host;
655 struct obd_export *exp;
656 struct ll_async_page *llap;
657 struct ll_sb_info *sbi = ll_i2sbi(inode);
661 LASSERT(!in_interrupt());
663 /* sync pages or failed read pages can leave pages in the page
664 * cache that don't have our data associated with them anymore */
665 if (page->private == 0) {
670 LL_CDEBUG_PAGE(D_PAGE, page, "being evicted\n");
672 exp = ll_i2dtexp(inode);
674 CERROR("page %p ind %lu gave null export\n", page, page->index);
679 llap = llap_from_page(page);
681 CERROR("page %p ind %lu couldn't find llap: %ld\n", page,
682 page->index, PTR_ERR(llap));
687 //llap_write_complete(inode, llap);
688 rc = obd_teardown_async_page(exp, ll_i2info(inode)->lli_smd, NULL,
691 CERROR("page %p ind %lu failed: %d\n", page, page->index, rc);
693 /* this unconditional free is only safe because the page lock
694 * is providing exclusivity to memory pressure/truncate/writeback..*/
695 __clear_page_ll_data(page);
697 spin_lock(&sbi->ll_lock);
698 if (!list_empty(&llap->llap_proc_item))
699 list_del_init(&llap->llap_proc_item);
700 sbi->ll_pglist_gen++;
701 spin_unlock(&sbi->ll_lock);
702 OBD_FREE(llap, sizeof(*llap));
706 static int ll_page_matches(struct page *page, int fd_flags)
708 struct lustre_handle match_lockh = {0};
709 struct inode *inode = page->mapping->host;
710 ldlm_policy_data_t page_extent;
714 if (fd_flags & LL_FILE_GROUP_LOCKED)
717 page_extent.l_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
718 page_extent.l_extent.end =
719 page_extent.l_extent.start + PAGE_CACHE_SIZE - 1;
720 flags = LDLM_FL_CBPENDING | LDLM_FL_BLOCK_GRANTED | LDLM_FL_TEST_LOCK;
721 matches = obd_match(ll_i2sbi(inode)->ll_dt_exp,
722 ll_i2info(inode)->lli_smd, LDLM_EXTENT,
723 &page_extent, LCK_PR | LCK_PW, &flags, inode,
728 static int ll_issue_page_read(struct obd_export *exp,
729 struct ll_async_page *llap,
730 struct obd_io_group *oig, int defer)
732 struct page *page = llap->llap_page;
735 page_cache_get(page);
736 llap->llap_defer_uptodate = defer;
737 llap->llap_ra_used = 0;
738 rc = obd_queue_group_io(exp, ll_i2info(page->mapping->host)->lli_smd,
739 NULL, oig, llap->llap_cookie, OBD_BRW_READ, 0,
740 PAGE_SIZE, 0, ASYNC_COUNT_STABLE | ASYNC_READY
743 LL_CDEBUG_PAGE(D_ERROR, page, "read queue failed: rc %d\n", rc);
744 page_cache_release(page);
749 static void ll_ra_stats_inc_unlocked(struct ll_ra_info *ra, enum ra_stat which)
751 LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
752 ra->ra_stats[which]++;
755 static void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
757 struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
758 struct ll_ra_info *ra = &ll_i2sbi(mapping->host)->ll_ra_info;
760 spin_lock(&sbi->ll_lock);
761 ll_ra_stats_inc_unlocked(ra, which);
762 spin_unlock(&sbi->ll_lock);
765 void ll_ra_accounting(struct page *page, struct address_space *mapping)
767 struct ll_async_page *llap;
769 llap = llap_from_page(page);
773 if (!llap->llap_defer_uptodate || llap->llap_ra_used)
776 ll_ra_stats_inc(mapping, RA_STAT_DISCARDED);
779 #define RAS_CDEBUG(ras) \
780 CDEBUG(D_READA, "lrp %lu c %lu ws %lu wl %lu nra %lu\n", \
781 ras->ras_last_readpage, ras->ras_consecutive, \
782 ras->ras_window_start, ras->ras_window_len, \
783 ras->ras_next_readahead);
785 static int index_in_window(unsigned long index, unsigned long point,
786 unsigned long before, unsigned long after)
788 unsigned long start = point - before, end = point + after;
795 return start <= index && index <= end;
798 static int ll_readahead(struct ll_readahead_state *ras,
799 struct obd_export *exp, struct address_space *mapping,
800 struct obd_io_group *oig, int flags)
802 unsigned long i, start = 0, end = 0, reserved;
803 struct ll_async_page *llap;
805 int rc, ret = 0, match_failed = 0;
809 kms = lov_merge_size(ll_i2info(mapping->host)->lli_smd, 1);
811 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
814 spin_lock(&ras->ras_lock);
816 /* reserve a part of the read-ahead window that we'll be issuing */
817 if (ras->ras_window_len) {
818 start = ras->ras_next_readahead;
819 end = ras->ras_window_start + ras->ras_window_len - 1;
820 end = min(end, (unsigned long)(kms >> PAGE_CACHE_SHIFT));
821 ras->ras_next_readahead = max(end, end + 1);
826 spin_unlock(&ras->ras_lock);
829 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
833 reserved = ll_ra_count_get(ll_i2sbi(mapping->host), end - start + 1);
834 if (reserved < end - start + 1)
835 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
837 for (i = start; reserved > 0 && !match_failed && i <= end; i++) {
838 /* skip locked pages from previous readpage calls */
839 page = grab_cache_page_nowait(mapping, i);
841 CDEBUG(D_READA, "g_c_p_n failed\n");
845 /* we do this first so that we can see the page in the /proc
847 llap = llap_from_page(page);
848 if (IS_ERR(llap) || llap->llap_defer_uptodate)
851 /* skip completed pages */
852 if (Page_Uptodate(page))
855 /* bail when we hit the end of the lock. */
856 if ((rc = ll_page_matches(page, flags)) <= 0) {
857 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
858 "lock match failed: rc %d\n", rc);
859 ll_ra_stats_inc(mapping, RA_STAT_FAILED_MATCH);
864 rc = ll_issue_page_read(exp, llap, oig, 1);
868 LL_CDEBUG_PAGE(D_READA| D_PAGE, page,
869 "started read-ahead\n");
873 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
874 "skipping read-ahead\n");
878 page_cache_release(page);
881 LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
883 ll_ra_count_put(ll_i2sbi(mapping->host), reserved);
885 if (i == end + 1 && end == (kms >> PAGE_CACHE_SHIFT))
886 ll_ra_stats_inc(mapping, RA_STAT_EOF);
888 /* if we didn't get to the end of the region we reserved from
889 * the ras we need to go back and update the ras so that the
890 * next read-ahead tries from where we left off. we only do so
891 * if the region we failed to issue read-ahead on is still ahead
892 * of the app and behind the next index to start read-ahead from */
894 spin_lock(&ras->ras_lock);
895 if (i < ras->ras_next_readahead &&
896 index_in_window(i, ras->ras_window_start, 0,
897 ras->ras_window_len)) {
898 ras->ras_next_readahead = i;
901 spin_unlock(&ras->ras_lock);
907 static void ras_set_start(struct ll_readahead_state *ras, unsigned long index)
909 ras->ras_window_start = index & (~(PTLRPC_MAX_BRW_PAGES - 1));
912 /* called with the ras_lock held or from places where it doesn't matter */
913 static void ras_reset(struct ll_readahead_state *ras, unsigned long index)
915 ras->ras_last_readpage = index;
916 ras->ras_consecutive = 1;
917 ras->ras_window_len = 0;
918 ras_set_start(ras, index);
919 ras->ras_next_readahead = ras->ras_window_start;
924 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
926 spin_lock_init(&ras->ras_lock);
930 static void ras_update(struct ll_sb_info *sbi, struct ll_readahead_state *ras,
931 unsigned long index, unsigned hit)
933 struct ll_ra_info *ra = &sbi->ll_ra_info;
937 spin_lock(&sbi->ll_lock);
938 spin_lock(&ras->ras_lock);
940 ll_ra_stats_inc_unlocked(ra, hit ? RA_STAT_HIT : RA_STAT_MISS);
942 /* reset the read-ahead window in two cases. First when the app seeks
943 * or reads to some other part of the file. Secondly if we get a
944 * read-ahead miss that we think we've previously issued. This can
945 * be a symptom of there being so many read-ahead pages that the VM is
946 * reclaiming it before we get to it. */
947 if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
949 ll_ra_stats_inc_unlocked(ra, RA_STAT_DISTANT_READPAGE);
950 } else if (!hit && ras->ras_window_len &&
951 index < ras->ras_next_readahead &&
952 index_in_window(index, ras->ras_window_start, 0,
953 ras->ras_window_len)) {
955 ll_ra_stats_inc_unlocked(ra, RA_STAT_MISS_IN_WINDOW);
959 ras_reset(ras, index);
963 ras->ras_last_readpage = index;
964 ras->ras_consecutive++;
965 ras_set_start(ras, index);
966 ras->ras_next_readahead = max(ras->ras_window_start,
967 ras->ras_next_readahead);
969 /* wait for a few pages to arrive before issuing readahead to avoid
970 * the worst overutilization */
971 if (ras->ras_consecutive == 3) {
972 ras->ras_window_len = PTLRPC_MAX_BRW_PAGES;
976 /* we need to increase the window sometimes. we'll arbitrarily
977 * do it half-way through the pages in an rpc */
978 if ((index & (PTLRPC_MAX_BRW_PAGES - 1)) ==
979 (PTLRPC_MAX_BRW_PAGES >> 1)) {
980 ras->ras_window_len += PTLRPC_MAX_BRW_PAGES;
981 ras->ras_window_len = min(ras->ras_window_len,
989 spin_unlock(&ras->ras_lock);
990 spin_unlock(&sbi->ll_lock);
994 * for now we do our readpage the same on both 2.4 and 2.5. The kernel's
995 * read-ahead assumes it is valid to issue readpage all the way up to
996 * i_size, but our dlm locks make that not the case. We disable the
997 * kernel's read-ahead and do our own by walking ahead in the page cache
998 * checking for dlm lock coverage. the main difference between 2.4 and
999 * 2.6 is how read-ahead gets batched and issued, but we're using our own,
1000 * so they look the same.
1002 int ll_readpage(struct file *filp, struct page *page)
1004 struct ll_file_data *fd = filp->private_data;
1005 struct inode *inode = page->mapping->host;
1006 struct obd_export *exp;
1007 struct ll_async_page *llap;
1008 struct obd_io_group *oig = NULL;
1012 LASSERT(PageLocked(page));
1013 LASSERT(!PageUptodate(page));
1014 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p),offset="LPX64"\n",
1015 inode->i_ino, inode->i_generation, inode,
1016 (((obd_off)page->index) << PAGE_SHIFT));
1017 LASSERT(atomic_read(&filp->f_dentry->d_inode->i_count) > 0);
1019 rc = oig_init(&oig);
1023 exp = ll_i2dtexp(inode);
1025 GOTO(out, rc = -EINVAL);
1027 llap = llap_from_page(page);
1029 GOTO(out, rc = PTR_ERR(llap));
1031 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1032 ras_update(ll_i2sbi(inode), &fd->fd_ras, page->index,
1033 llap->llap_defer_uptodate);
1035 if (llap->llap_defer_uptodate) {
1036 llap->llap_ra_used = 1;
1037 rc = ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1040 obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd,
1042 LL_CDEBUG_PAGE(D_PAGE, page, "marking uptodate from defer\n");
1043 SetPageUptodate(page);
1045 GOTO(out_oig, rc = 0);
1048 rc = ll_page_matches(page, fd->fd_flags);
1050 LL_CDEBUG_PAGE(D_ERROR, page, "lock match failed: rc %d\n", rc);
1055 CWARN("ino %lu page %lu (%llu) not covered by "
1056 "a lock (mmap?). check debug logs.\n",
1057 inode->i_ino, page->index,
1058 (long long)page->index << PAGE_CACHE_SHIFT);
1061 rc = ll_issue_page_read(exp, llap, oig, 0);
1065 LL_CDEBUG_PAGE(D_PAGE, page, "queued readpage\n");
1066 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1067 ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1070 rc = obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig);