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 __u64 lov_merge_size(struct lov_stripe_md *lsm, int kms);
109 /* this isn't where truncate starts. roughly:
110 * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate
111 * we grab the lock back in setattr_raw to avoid races. */
112 void ll_truncate(struct inode *inode)
114 struct lov_stripe_md *lsm = ll_i2info(inode)->lli_smd;
115 struct obdo *oa = NULL;
119 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p)\n", inode->i_ino,
120 inode->i_generation, inode);
123 CDEBUG(D_INODE, "truncate on inode %lu with no objects\n",
129 if (lov_merge_size(lsm, 0) == inode->i_size) {
130 CDEBUG(D_VFSTRACE, "skipping punch for "LPX64" (size = %llu)\n",
131 lsm->lsm_object_id, inode->i_size);
133 CDEBUG(D_INFO, "calling punch for "LPX64" (new size %llu)\n",
134 lsm->lsm_object_id, inode->i_size);
138 CERROR("cannot alloc oa, error %d\n",
144 oa->o_id = lsm->lsm_object_id;
145 oa->o_gr = lsm->lsm_object_gr;
146 oa->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP;
147 obdo_from_inode(oa, inode, OBD_MD_FLTYPE | OBD_MD_FLMODE |
148 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
150 /* truncate == punch from new size to absolute end of file */
151 /* NB: obd_punch must be called with i_sem held! It updates the kms! */
152 rc = obd_punch(ll_i2dtexp(inode), oa, lsm, inode->i_size,
153 OBD_OBJECT_EOF, NULL);
155 CERROR("obd_truncate fails (%d) ino %lu\n", rc, inode->i_ino);
157 obdo_to_inode(inode, oa, OBD_MD_FLSIZE | OBD_MD_FLBLOCKS |
158 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
167 int ll_prepare_write(struct file *file, struct page *page, unsigned from,
170 struct inode *inode = page->mapping->host;
171 struct ll_inode_info *lli = ll_i2info(inode);
172 struct lov_stripe_md *lsm = lli->lli_smd;
173 obd_off offset = ((obd_off)page->index) << PAGE_SHIFT;
174 struct obdo *oa = NULL;
180 LASSERT(PageLocked(page));
181 (void)llap_cast_private(page); /* assertion */
183 /* Check to see if we should return -EIO right away */
185 pga.disk_offset = pga.page_offset = offset;
186 pga.count = PAGE_SIZE;
193 oa->o_id = lsm->lsm_object_id;
194 oa->o_gr = lsm->lsm_object_gr;
195 oa->o_mode = inode->i_mode;
196 oa->o_valid = OBD_MD_FLID | OBD_MD_FLMODE |
197 OBD_MD_FLTYPE | OBD_MD_FLGROUP;
199 rc = obd_brw(OBD_BRW_CHECK, ll_i2dtexp(inode), oa, lsm,
202 GOTO(out_free_oa, rc);
204 if (PageUptodate(page))
205 GOTO(out_free_oa, 0);
207 /* We're completely overwriting an existing page, so _don't_ set it up
208 * to date until commit_write */
209 if (from == 0 && to == PAGE_SIZE) {
210 POISON_PAGE(page, 0x11);
211 GOTO(out_free_oa, 0);
214 /* If are writing to a new page, no need to read old data. The extent
215 * locking will have updated the KMS, and for our purposes here we can
216 * treat it like i_size. */
217 kms = lov_merge_size(lsm, 1);
219 memset(kmap(page), 0, PAGE_SIZE);
221 GOTO(prepare_done, rc = 0);
224 /* XXX could be an async ocp read.. read-ahead? */
225 rc = ll_brw(OBD_BRW_READ, inode, oa, page, 0);
227 /* bug 1598: don't clobber blksize */
228 oa->o_valid &= ~(OBD_MD_FLSIZE | OBD_MD_FLBLKSZ);
229 obdo_refresh_inode(inode, oa, oa->o_valid);
235 SetPageUptodate(page);
241 struct ll_async_page *llap_from_cookie(void *cookie)
243 struct ll_async_page *llap = cookie;
244 if (llap->llap_magic != LLAP_MAGIC)
245 return ERR_PTR(-EINVAL);
249 static int ll_ap_make_ready(void *data, int cmd)
251 struct ll_async_page *llap;
255 llap = llap_from_cookie(data);
259 page = llap->llap_page;
261 LASSERT(cmd != OBD_BRW_READ);
263 /* we're trying to write, but the page is locked.. come back later */
264 if (TryLockPage(page))
267 LL_CDEBUG_PAGE(D_PAGE, page, "made ready\n");
268 page_cache_get(page);
270 /* if we left PageDirty we might get another writepage call
271 * in the future. list walkers are bright enough
272 * to check page dirty so we can leave it on whatever list
273 * its on. XXX also, we're called with the cli list so if
274 * we got the page cache list we'd create a lock inversion
275 * with the removepage path which gets the page lock then the
277 clear_page_dirty(page);
281 /* We have two reasons for giving llite the opportunity to change the
282 * write length of a given queued page as it builds the RPC containing
285 * 1) Further extending writes may have landed in the page cache
286 * since a partial write first queued this page requiring us
287 * to write more from the page cache.
288 * 2) We might have raced with truncate and want to avoid performing
289 * write RPCs that are just going to be thrown away by the
290 * truncate's punch on the storage targets.
292 * The kms serves these purposes as it is set at both truncate and extending
295 static int ll_ap_refresh_count(void *data, int cmd)
297 struct ll_async_page *llap;
298 struct lov_stripe_md *lsm;
303 /* readpage queues with _COUNT_STABLE, shouldn't get here. */
304 LASSERT(cmd != OBD_BRW_READ);
306 llap = llap_from_cookie(data);
308 RETURN(PTR_ERR(llap));
310 page = llap->llap_page;
311 lsm = ll_i2info(page->mapping->host)->lli_smd;
312 kms = lov_merge_size(lsm, 1);
314 /* catch race with truncate */
315 if (((__u64)page->index << PAGE_SHIFT) >= kms)
318 /* catch sub-page write at end of file */
319 if (((__u64)page->index << PAGE_SHIFT) + PAGE_SIZE > kms)
320 return kms % PAGE_SIZE;
325 void ll_inode_fill_obdo(struct inode *inode, int cmd, struct obdo *oa)
327 struct lov_stripe_md *lsm;
328 obd_valid valid_flags;
330 lsm = ll_i2info(inode)->lli_smd;
332 oa->o_id = lsm->lsm_object_id;
333 oa->o_gr = lsm->lsm_object_gr;
334 oa->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP;
335 valid_flags = OBD_MD_FLTYPE | OBD_MD_FLATIME;
336 if (cmd == OBD_BRW_WRITE) {
337 oa->o_valid |= OBD_MD_FLIFID | OBD_MD_FLEPOCH;
338 mdc_pack_id(obdo_id(oa), inode->i_ino, 0, inode->i_mode,
339 id_group(&ll_i2info(inode)->lli_id),
340 id_fid(&ll_i2info(inode)->lli_id));
342 oa->o_easize = ll_i2info(inode)->lli_io_epoch;
343 valid_flags |= OBD_MD_FLMTIME | OBD_MD_FLCTIME;
346 obdo_from_inode(oa, inode, valid_flags);
349 static void ll_ap_fill_obdo(void *data, int cmd, struct obdo *oa)
351 struct ll_async_page *llap;
354 llap = llap_from_cookie(data);
360 ll_inode_fill_obdo(llap->llap_page->mapping->host, cmd, oa);
364 static struct obd_async_page_ops ll_async_page_ops = {
365 .ap_make_ready = ll_ap_make_ready,
366 .ap_refresh_count = ll_ap_refresh_count,
367 .ap_fill_obdo = ll_ap_fill_obdo,
368 .ap_completion = ll_ap_completion,
371 struct ll_async_page *llap_cast_private(struct page *page)
373 struct ll_async_page *llap = (struct ll_async_page *)page->private;
375 LASSERTF(llap == NULL || llap->llap_magic == LLAP_MAGIC,
376 "page %p private %lu gave magic %d which != %d\n",
377 page, page->private, llap->llap_magic, LLAP_MAGIC);
382 /* XXX have the exp be an argument? */
383 struct ll_async_page *llap_from_page(struct page *page)
385 struct ll_async_page *llap;
386 struct obd_export *exp;
387 struct inode *inode = page->mapping->host;
388 struct ll_sb_info *sbi = ll_i2sbi(inode);
392 llap = llap_cast_private(page);
396 exp = ll_i2dtexp(page->mapping->host);
398 RETURN(ERR_PTR(-EINVAL));
400 OBD_ALLOC(llap, sizeof(*llap));
402 RETURN(ERR_PTR(-ENOMEM));
403 llap->llap_magic = LLAP_MAGIC;
404 rc = obd_prep_async_page(exp, ll_i2info(inode)->lli_smd, NULL, page,
405 (obd_off)page->index << PAGE_SHIFT,
406 &ll_async_page_ops, llap, &llap->llap_cookie);
408 OBD_FREE(llap, sizeof(*llap));
412 CDEBUG(D_CACHE, "llap %p page %p cookie %p obj off "LPU64"\n", llap,
413 page, llap->llap_cookie, (obd_off)page->index << PAGE_SHIFT);
414 /* also zeroing the PRIVBITS low order bitflags */
415 __set_page_ll_data(page, llap);
416 llap->llap_page = page;
418 spin_lock(&sbi->ll_lock);
419 sbi->ll_pglist_gen++;
420 list_add_tail(&llap->llap_proc_item, &sbi->ll_pglist);
421 spin_unlock(&sbi->ll_lock);
426 static int queue_or_sync_write(struct obd_export *exp,
427 struct lov_stripe_md *lsm,
428 struct ll_async_page *llap,
430 obd_flags async_flags)
432 struct obd_io_group *oig;
436 /* _make_ready only sees llap once we've unlocked the page */
437 llap->llap_write_queued = 1;
438 rc = obd_queue_async_io(exp, lsm, NULL, llap->llap_cookie,
439 OBD_BRW_WRITE, 0, 0, 0, async_flags);
441 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page, "write queued\n");
442 //llap_write_pending(inode, llap);
446 llap->llap_write_queued = 0;
452 rc = obd_queue_group_io(exp, lsm, NULL, oig, llap->llap_cookie,
453 OBD_BRW_WRITE, 0, to, 0, ASYNC_READY |
454 ASYNC_URGENT | ASYNC_COUNT_STABLE |
459 rc = obd_trigger_group_io(exp, lsm, NULL, oig);
465 if (!rc && async_flags & ASYNC_READY)
466 unlock_page(llap->llap_page);
468 LL_CDEBUG_PAGE(D_PAGE, llap->llap_page,
469 "sync write returned %d\n", rc);
478 void lov_increase_kms(struct obd_export *exp, struct lov_stripe_md *lsm,
481 /* be careful not to return success without setting the page Uptodate or
482 * the next pass through prepare_write will read in stale data from disk. */
483 int ll_commit_write(struct file *file, struct page *page, unsigned from,
486 struct inode *inode = page->mapping->host;
487 struct ll_inode_info *lli = ll_i2info(inode);
488 struct lov_stripe_md *lsm = lli->lli_smd;
489 struct obd_export *exp = NULL;
490 struct ll_async_page *llap;
495 SIGNAL_MASK_ASSERT(); /* XXX BUG 1511 */
496 LASSERT(inode == file->f_dentry->d_inode);
497 LASSERT(PageLocked(page));
499 CDEBUG(D_INODE, "inode %p is writing page %p from %d to %d at %lu\n",
500 inode, page, from, to, page->index);
502 llap = llap_from_page(page);
504 RETURN(PTR_ERR(llap));
506 /* queue a write for some time in the future the first time we
508 if (!PageDirty(page)) {
509 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
510 LPROC_LL_DIRTY_MISSES);
512 exp = ll_i2dtexp(inode);
516 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd, llap,
521 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
522 LPROC_LL_DIRTY_HITS);
525 /* put the page in the page cache, from now on ll_removepage is
526 * responsible for cleaning up the llap.
527 * don't dirty the page if it has been write out in q_o_s_w */
528 if (llap->llap_write_queued)
529 set_page_dirty(page);
533 size = (((obd_off)page->index) << PAGE_SHIFT) + to;
534 lov_increase_kms(ll_i2dtexp(inode), lsm, size);
535 if (size > inode->i_size)
536 inode->i_size = size;
537 SetPageUptodate(page);
542 int ll_writepage(struct page *page)
544 struct inode *inode = page->mapping->host;
545 struct obd_export *exp;
546 struct ll_async_page *llap;
550 LASSERT(!PageDirty(page));
551 LASSERT(PageLocked(page));
553 exp = ll_i2dtexp(inode);
555 GOTO(out, rc = -EINVAL);
557 llap = llap_from_page(page);
559 GOTO(out, rc = PTR_ERR(llap));
561 page_cache_get(page);
562 if (llap->llap_write_queued) {
563 LL_CDEBUG_PAGE(D_PAGE, page, "marking urgent\n");
564 rc = obd_set_async_flags(exp, ll_i2info(inode)->lli_smd, NULL,
566 ASYNC_READY | ASYNC_URGENT);
568 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd, llap,
569 PAGE_SIZE, ASYNC_READY |
573 page_cache_release(page);
582 ll_ra_count_get(struct ll_sb_info *sbi, unsigned long len)
584 struct ll_ra_info *ra = &sbi->ll_ra_info;
588 spin_lock(&sbi->ll_lock);
589 ret = min(ra->ra_max_pages - ra->ra_cur_pages, len);
590 ra->ra_cur_pages += ret;
591 spin_unlock(&sbi->ll_lock);
596 static void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
598 struct ll_ra_info *ra = &sbi->ll_ra_info;
599 spin_lock(&sbi->ll_lock);
600 LASSERTF(ra->ra_cur_pages >= len, "r_c_p %lu len %lu\n",
601 ra->ra_cur_pages, len);
602 ra->ra_cur_pages -= len;
603 spin_unlock(&sbi->ll_lock);
606 /* called for each page in a completed rpc.*/
607 void ll_ap_completion(void *data, int cmd, struct obdo *oa, int rc)
609 struct ll_async_page *llap;
613 llap = llap_from_cookie(data);
619 page = llap->llap_page;
620 LASSERT(PageLocked(page));
622 LL_CDEBUG_PAGE(D_PAGE, page, "completing cmd %d with %d\n", cmd, rc);
624 if (cmd == OBD_BRW_READ && llap->llap_defer_uptodate)
625 ll_ra_count_put(ll_i2sbi(page->mapping->host), 1);
628 if (cmd == OBD_BRW_READ) {
629 if (!llap->llap_defer_uptodate)
630 SetPageUptodate(page);
632 llap->llap_write_queued = 0;
634 ClearPageError(page);
636 if (cmd == OBD_BRW_READ)
637 llap->llap_defer_uptodate = 0;
643 if (0 && cmd == OBD_BRW_WRITE) {
644 llap_write_complete(page->mapping->host, llap);
645 ll_try_done_writing(page->mapping->host);
648 if (PageWriteback(page)) {
649 end_page_writeback(page);
651 page_cache_release(page);
655 /* the kernel calls us here when a page is unhashed from the page cache.
656 * the page will be locked and the kernel is holding a spinlock, so
657 * we need to be careful. we're just tearing down our book-keeping
659 void ll_removepage(struct page *page)
661 struct inode *inode = page->mapping->host;
662 struct obd_export *exp;
663 struct ll_async_page *llap;
664 struct ll_sb_info *sbi = ll_i2sbi(inode);
668 LASSERT(!in_interrupt());
670 /* sync pages or failed read pages can leave pages in the page
671 * cache that don't have our data associated with them anymore */
672 if (page->private == 0) {
677 LL_CDEBUG_PAGE(D_PAGE, page, "being evicted\n");
679 exp = ll_i2dtexp(inode);
681 CERROR("page %p ind %lu gave null export\n", page, page->index);
686 llap = llap_from_page(page);
688 CERROR("page %p ind %lu couldn't find llap: %ld\n", page,
689 page->index, PTR_ERR(llap));
694 //llap_write_complete(inode, llap);
695 rc = obd_teardown_async_page(exp, ll_i2info(inode)->lli_smd, NULL,
698 CERROR("page %p ind %lu failed: %d\n", page, page->index, rc);
700 /* this unconditional free is only safe because the page lock
701 * is providing exclusivity to memory pressure/truncate/writeback..*/
702 __clear_page_ll_data(page);
704 spin_lock(&sbi->ll_lock);
705 if (!list_empty(&llap->llap_proc_item))
706 list_del_init(&llap->llap_proc_item);
707 sbi->ll_pglist_gen++;
708 spin_unlock(&sbi->ll_lock);
709 OBD_FREE(llap, sizeof(*llap));
713 static int ll_page_matches(struct page *page, int fd_flags)
715 struct lustre_handle match_lockh = {0};
716 struct inode *inode = page->mapping->host;
717 ldlm_policy_data_t page_extent;
721 if (fd_flags & LL_FILE_GROUP_LOCKED)
724 page_extent.l_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
725 page_extent.l_extent.end =
726 page_extent.l_extent.start + PAGE_CACHE_SIZE - 1;
727 flags = LDLM_FL_CBPENDING | LDLM_FL_BLOCK_GRANTED | LDLM_FL_TEST_LOCK;
728 matches = obd_match(ll_i2sbi(inode)->ll_dt_exp,
729 ll_i2info(inode)->lli_smd, LDLM_EXTENT,
730 &page_extent, LCK_PR | LCK_PW, &flags, inode,
735 static int ll_issue_page_read(struct obd_export *exp,
736 struct ll_async_page *llap,
737 struct obd_io_group *oig, int defer)
739 struct page *page = llap->llap_page;
742 page_cache_get(page);
743 llap->llap_defer_uptodate = defer;
744 llap->llap_ra_used = 0;
745 rc = obd_queue_group_io(exp, ll_i2info(page->mapping->host)->lli_smd,
746 NULL, oig, llap->llap_cookie, OBD_BRW_READ, 0,
747 PAGE_SIZE, 0, ASYNC_COUNT_STABLE | ASYNC_READY
750 LL_CDEBUG_PAGE(D_ERROR, page, "read queue failed: rc %d\n", rc);
751 page_cache_release(page);
756 static void ll_ra_stats_inc_unlocked(struct ll_ra_info *ra, enum ra_stat which)
758 LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
759 ra->ra_stats[which]++;
762 static void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
764 struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
765 struct ll_ra_info *ra = &ll_i2sbi(mapping->host)->ll_ra_info;
767 spin_lock(&sbi->ll_lock);
768 ll_ra_stats_inc_unlocked(ra, which);
769 spin_unlock(&sbi->ll_lock);
772 void ll_ra_accounting(struct page *page, struct address_space *mapping)
774 struct ll_async_page *llap;
776 llap = llap_from_page(page);
780 if (!llap->llap_defer_uptodate || llap->llap_ra_used)
783 ll_ra_stats_inc(mapping, RA_STAT_DISCARDED);
786 #define RAS_CDEBUG(ras) \
787 CDEBUG(D_READA, "lrp %lu c %lu ws %lu wl %lu nra %lu\n", \
788 ras->ras_last_readpage, ras->ras_consecutive, \
789 ras->ras_window_start, ras->ras_window_len, \
790 ras->ras_next_readahead);
792 static int index_in_window(unsigned long index, unsigned long point,
793 unsigned long before, unsigned long after)
795 unsigned long start = point - before, end = point + after;
802 return start <= index && index <= end;
805 static int ll_readahead(struct ll_readahead_state *ras,
806 struct obd_export *exp, struct address_space *mapping,
807 struct obd_io_group *oig, int flags)
809 unsigned long i, start = 0, end = 0, reserved;
810 struct ll_async_page *llap;
812 int rc, ret = 0, match_failed = 0;
816 kms = lov_merge_size(ll_i2info(mapping->host)->lli_smd, 1);
818 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
821 spin_lock(&ras->ras_lock);
823 /* reserve a part of the read-ahead window that we'll be issuing */
824 if (ras->ras_window_len) {
825 start = ras->ras_next_readahead;
826 end = ras->ras_window_start + ras->ras_window_len - 1;
827 end = min(end, (unsigned long)(kms >> PAGE_CACHE_SHIFT));
828 ras->ras_next_readahead = max(end, end + 1);
833 spin_unlock(&ras->ras_lock);
836 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
840 reserved = ll_ra_count_get(ll_i2sbi(mapping->host), end - start + 1);
841 if (reserved < end - start + 1)
842 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
844 for (i = start; reserved > 0 && !match_failed && i <= end; i++) {
845 /* skip locked pages from previous readpage calls */
846 page = grab_cache_page_nowait(mapping, i);
848 CDEBUG(D_READA, "g_c_p_n failed\n");
852 /* we do this first so that we can see the page in the /proc
854 llap = llap_from_page(page);
855 if (IS_ERR(llap) || llap->llap_defer_uptodate)
858 /* skip completed pages */
859 if (Page_Uptodate(page))
862 /* bail when we hit the end of the lock. */
863 if ((rc = ll_page_matches(page, flags)) <= 0) {
864 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
865 "lock match failed: rc %d\n", rc);
866 ll_ra_stats_inc(mapping, RA_STAT_FAILED_MATCH);
871 rc = ll_issue_page_read(exp, llap, oig, 1);
875 LL_CDEBUG_PAGE(D_READA| D_PAGE, page,
876 "started read-ahead\n");
880 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
881 "skipping read-ahead\n");
885 page_cache_release(page);
888 LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
890 ll_ra_count_put(ll_i2sbi(mapping->host), reserved);
892 if (i == end + 1 && end == (kms >> PAGE_CACHE_SHIFT))
893 ll_ra_stats_inc(mapping, RA_STAT_EOF);
895 /* if we didn't get to the end of the region we reserved from
896 * the ras we need to go back and update the ras so that the
897 * next read-ahead tries from where we left off. we only do so
898 * if the region we failed to issue read-ahead on is still ahead
899 * of the app and behind the next index to start read-ahead from */
901 spin_lock(&ras->ras_lock);
902 if (i < ras->ras_next_readahead &&
903 index_in_window(i, ras->ras_window_start, 0,
904 ras->ras_window_len)) {
905 ras->ras_next_readahead = i;
908 spin_unlock(&ras->ras_lock);
914 static void ras_set_start(struct ll_readahead_state *ras, unsigned long index)
916 ras->ras_window_start = index & (~(PTLRPC_MAX_BRW_PAGES - 1));
919 /* called with the ras_lock held or from places where it doesn't matter */
920 static void ras_reset(struct ll_readahead_state *ras, unsigned long index)
922 ras->ras_last_readpage = index;
923 ras->ras_consecutive = 1;
924 ras->ras_window_len = 0;
925 ras_set_start(ras, index);
926 ras->ras_next_readahead = ras->ras_window_start;
931 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
933 spin_lock_init(&ras->ras_lock);
937 static void ras_update(struct ll_sb_info *sbi, struct ll_readahead_state *ras,
938 unsigned long index, unsigned hit)
940 struct ll_ra_info *ra = &sbi->ll_ra_info;
944 spin_lock(&sbi->ll_lock);
945 spin_lock(&ras->ras_lock);
947 ll_ra_stats_inc_unlocked(ra, hit ? RA_STAT_HIT : RA_STAT_MISS);
949 /* reset the read-ahead window in two cases. First when the app seeks
950 * or reads to some other part of the file. Secondly if we get a
951 * read-ahead miss that we think we've previously issued. This can
952 * be a symptom of there being so many read-ahead pages that the VM is
953 * reclaiming it before we get to it. */
954 if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
956 ll_ra_stats_inc_unlocked(ra, RA_STAT_DISTANT_READPAGE);
957 } else if (!hit && ras->ras_window_len &&
958 index < ras->ras_next_readahead &&
959 index_in_window(index, ras->ras_window_start, 0,
960 ras->ras_window_len)) {
962 ll_ra_stats_inc_unlocked(ra, RA_STAT_MISS_IN_WINDOW);
966 ras_reset(ras, index);
970 ras->ras_last_readpage = index;
971 ras->ras_consecutive++;
972 ras_set_start(ras, index);
973 ras->ras_next_readahead = max(ras->ras_window_start,
974 ras->ras_next_readahead);
976 /* wait for a few pages to arrive before issuing readahead to avoid
977 * the worst overutilization */
978 if (ras->ras_consecutive == 3) {
979 ras->ras_window_len = PTLRPC_MAX_BRW_PAGES;
983 /* we need to increase the window sometimes. we'll arbitrarily
984 * do it half-way through the pages in an rpc */
985 if ((index & (PTLRPC_MAX_BRW_PAGES - 1)) ==
986 (PTLRPC_MAX_BRW_PAGES >> 1)) {
987 ras->ras_window_len += PTLRPC_MAX_BRW_PAGES;
988 ras->ras_window_len = min(ras->ras_window_len,
996 spin_unlock(&ras->ras_lock);
997 spin_unlock(&sbi->ll_lock);
1001 * for now we do our readpage the same on both 2.4 and 2.5. The kernel's
1002 * read-ahead assumes it is valid to issue readpage all the way up to
1003 * i_size, but our dlm locks make that not the case. We disable the
1004 * kernel's read-ahead and do our own by walking ahead in the page cache
1005 * checking for dlm lock coverage. the main difference between 2.4 and
1006 * 2.6 is how read-ahead gets batched and issued, but we're using our own,
1007 * so they look the same.
1009 int ll_readpage(struct file *filp, struct page *page)
1011 struct ll_file_data *fd = filp->private_data;
1012 struct inode *inode = page->mapping->host;
1013 struct obd_export *exp;
1014 struct ll_async_page *llap;
1015 struct obd_io_group *oig = NULL;
1019 LASSERT(PageLocked(page));
1020 LASSERT(!PageUptodate(page));
1021 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p),offset="LPX64"\n",
1022 inode->i_ino, inode->i_generation, inode,
1023 (((obd_off)page->index) << PAGE_SHIFT));
1024 LASSERT(atomic_read(&filp->f_dentry->d_inode->i_count) > 0);
1026 rc = oig_init(&oig);
1030 exp = ll_i2dtexp(inode);
1032 GOTO(out, rc = -EINVAL);
1034 llap = llap_from_page(page);
1036 GOTO(out, rc = PTR_ERR(llap));
1038 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1039 ras_update(ll_i2sbi(inode), &fd->fd_ras, page->index,
1040 llap->llap_defer_uptodate);
1042 if (llap->llap_defer_uptodate) {
1043 llap->llap_ra_used = 1;
1044 rc = ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1047 obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd,
1049 LL_CDEBUG_PAGE(D_PAGE, page, "marking uptodate from defer\n");
1050 SetPageUptodate(page);
1052 GOTO(out_oig, rc = 0);
1055 rc = ll_page_matches(page, fd->fd_flags);
1057 LL_CDEBUG_PAGE(D_ERROR, page, "lock match failed: rc %d\n", rc);
1062 CWARN("ino %lu page %lu (%llu) not covered by "
1063 "a lock (mmap?). check debug logs.\n",
1064 inode->i_ino, page->index,
1065 (long long)page->index << PAGE_CACHE_SHIFT);
1068 rc = ll_issue_page_read(exp, llap, oig, 0);
1072 LL_CDEBUG_PAGE(D_PAGE, page, "queued readpage\n");
1073 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1074 ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1077 rc = obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig);