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);
110 * this isn't where truncate starts. roughly:
111 * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate
112 * we grab the lock back in setattr_raw to avoid races.
114 * must be called with lli_size_sem held.
116 void ll_truncate(struct inode *inode)
118 struct lov_stripe_md *lsm = ll_i2info(inode)->lli_smd;
119 struct ll_inode_info *lli = ll_i2info(inode);
120 struct obdo *oa = NULL;
124 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p) to %llu\n", inode->i_ino,
125 inode->i_generation, inode, inode->i_size);
128 CDEBUG(D_INODE, "truncate on inode %lu with no objects\n",
133 if (lov_merge_size(lsm, 0) == inode->i_size) {
134 CDEBUG(D_VFSTRACE, "skipping punch for "LPX64" (size = %llu)\n",
135 lsm->lsm_object_id, inode->i_size);
139 CDEBUG(D_INFO, "calling punch for "LPX64" (new size %llu)\n",
140 lsm->lsm_object_id, inode->i_size);
144 CERROR("cannot alloc oa, error %d\n",
150 oa->o_id = lsm->lsm_object_id;
151 oa->o_gr = lsm->lsm_object_gr;
152 oa->o_valid = OBD_MD_FLID | OBD_MD_FLGROUP;
153 obdo_from_inode(oa, inode, OBD_MD_FLTYPE | OBD_MD_FLMODE |
154 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
156 obd_adjust_kms(ll_i2dtexp(inode), lsm, inode->i_size, 1);
158 LASSERT(atomic_read(&lli->lli_size_sem.count) <= 0);
159 up(&lli->lli_size_sem);
161 rc = obd_punch(ll_i2dtexp(inode), oa, lsm, inode->i_size,
162 OBD_OBJECT_EOF, NULL);
164 CERROR("obd_truncate fails (%d) ino %lu\n", rc, inode->i_ino);
166 obdo_to_inode(inode, oa, OBD_MD_FLSIZE | OBD_MD_FLBLOCKS |
167 OBD_MD_FLATIME | OBD_MD_FLMTIME | OBD_MD_FLCTIME);
175 LASSERT(atomic_read(&lli->lli_size_sem.count) <= 0);
176 up(&lli->lli_size_sem);
179 int ll_prepare_write(struct file *file, struct page *page, unsigned from,
182 struct inode *inode = page->mapping->host;
183 struct ll_inode_info *lli = ll_i2info(inode);
184 struct lov_stripe_md *lsm = lli->lli_smd;
185 obd_off offset = ((obd_off)page->index) << PAGE_SHIFT;
186 struct obdo *oa = NULL;
192 LASSERT(PageLocked(page));
193 (void)llap_cast_private(page); /* assertion */
195 /* Check to see if we should return -EIO right away */
197 pga.disk_offset = pga.page_offset = offset;
198 pga.count = PAGE_SIZE;
205 oa->o_id = lsm->lsm_object_id;
206 oa->o_gr = lsm->lsm_object_gr;
207 oa->o_mode = inode->i_mode;
208 oa->o_valid = OBD_MD_FLID | OBD_MD_FLMODE |
209 OBD_MD_FLTYPE | OBD_MD_FLGROUP;
211 rc = obd_brw(OBD_BRW_CHECK, ll_i2dtexp(inode), oa, lsm,
214 GOTO(out_free_oa, rc);
216 if (PageUptodate(page))
217 GOTO(out_free_oa, 0);
219 /* We're completely overwriting an existing page, so _don't_ set it up
220 * to date until commit_write */
221 if (from == 0 && to == PAGE_SIZE) {
222 POISON_PAGE(page, 0x11);
223 GOTO(out_free_oa, 0);
226 /* If are writing to a new page, no need to read old data. The extent
227 * locking will have updated the KMS, and for our purposes here we can
228 * treat it like i_size. */
229 down(&lli->lli_size_sem);
230 kms = lov_merge_size(lsm, 1);
231 up(&lli->lli_size_sem);
233 memset(kmap(page), 0, PAGE_SIZE);
235 GOTO(prepare_done, rc = 0);
238 /* XXX could be an async ocp read.. read-ahead? */
239 rc = ll_brw(OBD_BRW_READ, inode, oa, page, 0);
241 /* bug 1598: don't clobber blksize */
242 oa->o_valid &= ~(OBD_MD_FLSIZE | OBD_MD_FLBLKSZ);
243 obdo_refresh_inode(inode, oa, oa->o_valid);
249 SetPageUptodate(page);
255 static int ll_ap_make_ready(void *data, int cmd)
257 struct ll_async_page *llap;
261 llap = LLAP_FROM_COOKIE(data);
262 page = llap->llap_page;
264 LASSERT(cmd != OBD_BRW_READ);
266 /* we're trying to write, but the page is locked.. come back later */
267 if (TryLockPage(page))
270 LL_CDEBUG_PAGE(D_PAGE, page, "made ready\n");
271 page_cache_get(page);
273 /* if we left PageDirty we might get another writepage call
274 * in the future. list walkers are bright enough
275 * to check page dirty so we can leave it on whatever list
276 * its on. XXX also, we're called with the cli list so if
277 * we got the page cache list we'd create a lock inversion
278 * with the removepage path which gets the page lock then the
280 clear_page_dirty(page);
284 /* We have two reasons for giving llite the opportunity to change the
285 * write length of a given queued page as it builds the RPC containing
288 * 1) Further extending writes may have landed in the page cache
289 * since a partial write first queued this page requiring us
290 * to write more from the page cache.
291 * 2) We might have raced with truncate and want to avoid performing
292 * write RPCs that are just going to be thrown away by the
293 * truncate's punch on the storage targets.
295 * The kms serves these purposes as it is set at both truncate and extending
298 static int ll_ap_refresh_count(void *data, int cmd)
300 struct ll_async_page *llap;
301 struct lov_stripe_md *lsm;
306 /* readpage queues with _COUNT_STABLE, shouldn't get here. */
307 LASSERT(cmd != OBD_BRW_READ);
309 llap = LLAP_FROM_COOKIE(data);
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);
355 ll_inode_fill_obdo(llap->llap_page->mapping->host, cmd, oa);
359 static struct obd_async_page_ops ll_async_page_ops = {
360 .ap_make_ready = ll_ap_make_ready,
361 .ap_refresh_count = ll_ap_refresh_count,
362 .ap_fill_obdo = ll_ap_fill_obdo,
363 .ap_completion = ll_ap_completion,
367 struct ll_async_page *llap_cast_private(struct page *page)
369 struct ll_async_page *llap = (struct ll_async_page *)page->private;
371 LASSERTF(llap == NULL || llap->llap_magic == LLAP_MAGIC,
372 "page %p private %lu gave magic %d which != %d\n",
373 page, page->private, llap->llap_magic, LLAP_MAGIC);
378 /* XXX have the exp be an argument? */
379 struct ll_async_page *llap_from_page(struct page *page, unsigned origin)
381 struct ll_async_page *llap;
382 struct obd_export *exp;
383 struct inode *inode = page->mapping->host;
384 struct ll_sb_info *sbi = ll_i2sbi(inode);
388 LASSERTF(origin < LLAP__ORIGIN_MAX, "%u\n", origin);
390 llap = llap_cast_private(page);
394 exp = ll_i2dtexp(page->mapping->host);
396 RETURN(ERR_PTR(-EINVAL));
398 OBD_ALLOC(llap, sizeof(*llap));
400 RETURN(ERR_PTR(-ENOMEM));
401 llap->llap_magic = LLAP_MAGIC;
402 rc = obd_prep_async_page(exp, ll_i2info(inode)->lli_smd, NULL, page,
403 (obd_off)page->index << PAGE_SHIFT,
404 &ll_async_page_ops, llap, &llap->llap_cookie);
406 OBD_FREE(llap, sizeof(*llap));
410 CDEBUG(D_CACHE, "llap %p page %p cookie %p obj off "LPU64"\n", llap,
411 page, llap->llap_cookie, (obd_off)page->index << PAGE_SHIFT);
412 /* also zeroing the PRIVBITS low order bitflags */
413 __set_page_ll_data(page, llap);
414 llap->llap_page = page;
416 spin_lock(&sbi->ll_lock);
417 sbi->ll_pglist_gen++;
418 list_add_tail(&llap->llap_proc_item, &sbi->ll_pglist);
419 spin_unlock(&sbi->ll_lock);
422 llap->llap_origin = origin;
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 /* be careful not to return success without setting the page Uptodate or
479 * the next pass through prepare_write will read in stale data from disk. */
480 int ll_commit_write(struct file *file, struct page *page, unsigned from,
483 struct inode *inode = page->mapping->host;
484 struct ll_inode_info *lli = ll_i2info(inode);
485 struct lov_stripe_md *lsm = lli->lli_smd;
486 struct obd_export *exp = NULL;
487 struct ll_async_page *llap;
492 SIGNAL_MASK_ASSERT(); /* XXX BUG 1511 */
493 LASSERT(inode == file->f_dentry->d_inode);
494 LASSERT(PageLocked(page));
496 CDEBUG(D_INODE, "inode %p is writing page %p from %d to %d at %lu\n",
497 inode, page, from, to, page->index);
499 llap = llap_from_page(page, LLAP_ORIGIN_COMMIT_WRITE);
501 RETURN(PTR_ERR(llap));
503 exp = ll_i2dtexp(inode);
507 /* queue a write for some time in the future the first time we
509 if (!PageDirty(page)) {
510 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
511 LPROC_LL_DIRTY_MISSES);
513 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd,
518 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
519 LPROC_LL_DIRTY_HITS);
522 /* put the page in the page cache, from now on ll_removepage is
523 * responsible for cleaning up the llap.
524 * don't dirty the page if it has been write out in q_o_s_w */
525 if (llap->llap_write_queued)
526 set_page_dirty(page);
529 size = (((obd_off)page->index) << PAGE_SHIFT) + to;
530 down(&lli->lli_size_sem);
532 obd_adjust_kms(exp, lsm, size, 0);
533 if (size > inode->i_size)
534 inode->i_size = size;
535 SetPageUptodate(page);
536 } else if (size > inode->i_size) {
537 /* this page beyond the pales of i_size, so it can't be
538 * truncated in ll_p_r_e during lock revoking. we must
539 * teardown our book-keeping here. */
542 up(&lli->lli_size_sem);
546 static unsigned long ll_ra_count_get(struct ll_sb_info *sbi, unsigned long len)
548 struct ll_ra_info *ra = &sbi->ll_ra_info;
552 spin_lock(&sbi->ll_lock);
553 ret = min(ra->ra_max_pages - ra->ra_cur_pages, len);
554 ra->ra_cur_pages += ret;
555 spin_unlock(&sbi->ll_lock);
560 static void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
562 struct ll_ra_info *ra = &sbi->ll_ra_info;
563 spin_lock(&sbi->ll_lock);
564 LASSERTF(ra->ra_cur_pages >= len, "r_c_p %lu len %lu\n",
565 ra->ra_cur_pages, len);
566 ra->ra_cur_pages -= len;
567 spin_unlock(&sbi->ll_lock);
570 int ll_writepage(struct page *page)
572 struct inode *inode = page->mapping->host;
573 struct obd_export *exp;
574 struct ll_async_page *llap;
578 LASSERT(!PageDirty(page));
579 LASSERT(PageLocked(page));
581 exp = ll_i2dtexp(inode);
583 GOTO(out, rc = -EINVAL);
585 llap = llap_from_page(page, LLAP_ORIGIN_WRITEPAGE);
587 GOTO(out, rc = PTR_ERR(llap));
589 page_cache_get(page);
590 if (llap->llap_write_queued) {
591 LL_CDEBUG_PAGE(D_PAGE, page, "marking urgent\n");
592 rc = obd_set_async_flags(exp, ll_i2info(inode)->lli_smd, NULL,
594 ASYNC_READY | ASYNC_URGENT);
596 rc = queue_or_sync_write(exp, ll_i2info(inode)->lli_smd, llap,
597 PAGE_SIZE, ASYNC_READY |
601 page_cache_release(page);
609 /* called for each page in a completed rpc.*/
610 void ll_ap_completion(void *data, int cmd, struct obdo *oa, int rc)
612 struct ll_async_page *llap;
616 llap = LLAP_FROM_COOKIE(data);
617 page = llap->llap_page;
618 LASSERT(PageLocked(page));
620 LL_CDEBUG_PAGE(D_PAGE, page, "completing cmd %d with %d\n", cmd, rc);
622 if (cmd == OBD_BRW_READ && llap->llap_defer_uptodate)
623 ll_ra_count_put(ll_i2sbi(page->mapping->host), 1);
626 if (cmd == OBD_BRW_READ) {
627 if (!llap->llap_defer_uptodate)
628 SetPageUptodate(page);
630 llap->llap_write_queued = 0;
632 ClearPageError(page);
634 if (cmd == OBD_BRW_READ)
635 llap->llap_defer_uptodate = 0;
641 if (0 && cmd == OBD_BRW_WRITE) {
642 llap_write_complete(page->mapping->host, llap);
643 ll_try_done_writing(page->mapping->host);
646 if (PageWriteback(page)) {
647 end_page_writeback(page);
649 page_cache_release(page);
653 /* the kernel calls us here when a page is unhashed from the page cache.
654 * the page will be locked and the kernel is holding a spinlock, so
655 * we need to be careful. we're just tearing down our book-keeping
657 void ll_removepage(struct page *page)
659 struct inode *inode = page->mapping->host;
660 struct obd_export *exp;
661 struct ll_async_page *llap;
662 struct ll_sb_info *sbi = ll_i2sbi(inode);
666 LASSERT(!in_interrupt());
668 /* sync pages or failed read pages can leave pages in the page
669 * cache that don't have our data associated with them anymore */
670 if (page->private == 0) {
675 LL_CDEBUG_PAGE(D_PAGE, page, "being evicted\n");
677 exp = ll_i2dtexp(inode);
679 CERROR("page %p ind %lu gave null export\n", page, page->index);
684 llap = llap_from_page(page, 0);
686 CERROR("page %p ind %lu couldn't find llap: %ld\n", page,
687 page->index, PTR_ERR(llap));
692 //llap_write_complete(inode, llap);
693 rc = obd_teardown_async_page(exp, ll_i2info(inode)->lli_smd, NULL,
696 CERROR("page %p ind %lu failed: %d\n", page, page->index, rc);
698 /* this unconditional free is only safe because the page lock
699 * is providing exclusivity to memory pressure/truncate/writeback..*/
700 __clear_page_ll_data(page);
702 spin_lock(&sbi->ll_lock);
703 if (!list_empty(&llap->llap_proc_item))
704 list_del_init(&llap->llap_proc_item);
705 sbi->ll_pglist_gen++;
706 spin_unlock(&sbi->ll_lock);
707 OBD_FREE(llap, sizeof(*llap));
711 static int ll_page_matches(struct page *page, int fd_flags)
713 struct lustre_handle match_lockh = {0};
714 struct inode *inode = page->mapping->host;
715 ldlm_policy_data_t page_extent;
719 if (fd_flags & LL_FILE_GROUP_LOCKED)
722 page_extent.l_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
723 page_extent.l_extent.end =
724 page_extent.l_extent.start + PAGE_CACHE_SIZE - 1;
725 flags = LDLM_FL_CBPENDING | LDLM_FL_BLOCK_GRANTED | LDLM_FL_TEST_LOCK;
726 matches = obd_match(ll_i2sbi(inode)->ll_dt_exp,
727 ll_i2info(inode)->lli_smd, LDLM_EXTENT,
728 &page_extent, LCK_PR | LCK_PW, &flags, inode,
733 static int ll_issue_page_read(struct obd_export *exp,
734 struct ll_async_page *llap,
735 struct obd_io_group *oig, int defer)
737 struct page *page = llap->llap_page;
740 page_cache_get(page);
741 llap->llap_defer_uptodate = defer;
742 llap->llap_ra_used = 0;
743 rc = obd_queue_group_io(exp, ll_i2info(page->mapping->host)->lli_smd,
744 NULL, oig, llap->llap_cookie, OBD_BRW_READ, 0,
745 PAGE_SIZE, 0, ASYNC_COUNT_STABLE | ASYNC_READY
748 LL_CDEBUG_PAGE(D_ERROR, page, "read queue failed: rc %d\n", rc);
749 page_cache_release(page);
754 static void ll_ra_stats_inc_unlocked(struct ll_ra_info *ra, enum ra_stat which)
756 LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
757 ra->ra_stats[which]++;
760 static void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
762 struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
763 struct ll_ra_info *ra = &ll_i2sbi(mapping->host)->ll_ra_info;
765 spin_lock(&sbi->ll_lock);
766 ll_ra_stats_inc_unlocked(ra, which);
767 spin_unlock(&sbi->ll_lock);
770 void ll_ra_accounting(struct page *page, struct address_space *mapping)
772 struct ll_async_page *llap;
774 llap = llap_from_page(page, LLAP_ORIGIN_WRITEPAGE);
778 if (!llap->llap_defer_uptodate || llap->llap_ra_used)
781 ll_ra_stats_inc(mapping, RA_STAT_DISCARDED);
784 #define RAS_CDEBUG(ras) \
785 CDEBUG(D_READA, "lrp %lu c %lu ws %lu wl %lu nra %lu\n", \
786 ras->ras_last_readpage, ras->ras_consecutive, \
787 ras->ras_window_start, ras->ras_window_len, \
788 ras->ras_next_readahead);
790 static int index_in_window(unsigned long index, unsigned long point,
791 unsigned long before, unsigned long after)
793 unsigned long start = point - before, end = point + after;
800 return start <= index && index <= end;
803 static int ll_readahead(struct ll_readahead_state *ras,
804 struct obd_export *exp, struct address_space *mapping,
805 struct obd_io_group *oig, int flags)
807 unsigned long i, start = 0, end = 0, reserved;
808 struct ll_async_page *llap;
810 int rc, ret = 0, match_failed = 0;
814 kms = lov_merge_size(ll_i2info(mapping->host)->lli_smd, 1);
816 ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
819 spin_lock(&ras->ras_lock);
821 /* reserve a part of the read-ahead window that we'll be issuing */
822 if (ras->ras_window_len) {
823 start = ras->ras_next_readahead;
824 end = ras->ras_window_start + ras->ras_window_len - 1;
825 end = min(end, (unsigned long)(kms >> PAGE_CACHE_SHIFT));
826 ras->ras_next_readahead = max(end, end + 1);
831 spin_unlock(&ras->ras_lock);
834 ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
838 reserved = ll_ra_count_get(ll_i2sbi(mapping->host), end - start + 1);
839 if (reserved < end - start + 1)
840 ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
842 for (i = start; reserved > 0 && !match_failed && i <= end; i++) {
843 /* skip locked pages from previous readpage calls */
844 page = grab_cache_page_nowait(mapping, i);
846 CDEBUG(D_READA, "g_c_p_n failed\n");
850 /* we do this first so that we can see the page in the /proc
852 llap = llap_from_page(page, LLAP_ORIGIN_READAHEAD);
853 if (IS_ERR(llap) || llap->llap_defer_uptodate)
856 /* skip completed pages */
857 if (Page_Uptodate(page))
860 /* bail when we hit the end of the lock. */
861 if ((rc = ll_page_matches(page, flags)) <= 0) {
862 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
863 "lock match failed: rc %d\n", rc);
864 ll_ra_stats_inc(mapping, RA_STAT_FAILED_MATCH);
869 rc = ll_issue_page_read(exp, llap, oig, 1);
873 LL_CDEBUG_PAGE(D_READA| D_PAGE, page,
874 "started read-ahead\n");
878 LL_CDEBUG_PAGE(D_READA | D_PAGE, page,
879 "skipping read-ahead\n");
883 page_cache_release(page);
886 LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
888 ll_ra_count_put(ll_i2sbi(mapping->host), reserved);
890 if (i == end + 1 && end == (kms >> PAGE_CACHE_SHIFT))
891 ll_ra_stats_inc(mapping, RA_STAT_EOF);
893 /* if we didn't get to the end of the region we reserved from
894 * the ras we need to go back and update the ras so that the
895 * next read-ahead tries from where we left off. we only do so
896 * if the region we failed to issue read-ahead on is still ahead
897 * of the app and behind the next index to start read-ahead from */
899 spin_lock(&ras->ras_lock);
900 if (i < ras->ras_next_readahead &&
901 index_in_window(i, ras->ras_window_start, 0,
902 ras->ras_window_len)) {
903 ras->ras_next_readahead = i;
906 spin_unlock(&ras->ras_lock);
912 static void ras_set_start(struct ll_readahead_state *ras, unsigned long index)
914 ras->ras_window_start = index & (~(PTLRPC_MAX_BRW_PAGES - 1));
917 /* called with the ras_lock held or from places where it doesn't matter */
918 static void ras_reset(struct ll_readahead_state *ras, unsigned long index)
920 ras->ras_last_readpage = index;
921 ras->ras_consecutive = 1;
922 ras->ras_window_len = 0;
923 ras_set_start(ras, index);
924 ras->ras_next_readahead = ras->ras_window_start;
929 void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
931 spin_lock_init(&ras->ras_lock);
935 static void ras_update(struct ll_sb_info *sbi, struct ll_readahead_state *ras,
936 unsigned long index, unsigned hit)
938 struct ll_ra_info *ra = &sbi->ll_ra_info;
942 spin_lock(&sbi->ll_lock);
943 spin_lock(&ras->ras_lock);
945 ll_ra_stats_inc_unlocked(ra, hit ? RA_STAT_HIT : RA_STAT_MISS);
947 /* reset the read-ahead window in two cases. First when the app seeks
948 * or reads to some other part of the file. Secondly if we get a
949 * read-ahead miss that we think we've previously issued. This can
950 * be a symptom of there being so many read-ahead pages that the VM is
951 * reclaiming it before we get to it. */
952 if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
954 ll_ra_stats_inc_unlocked(ra, RA_STAT_DISTANT_READPAGE);
955 } else if (!hit && ras->ras_window_len &&
956 index < ras->ras_next_readahead &&
957 index_in_window(index, ras->ras_window_start, 0,
958 ras->ras_window_len)) {
960 ll_ra_stats_inc_unlocked(ra, RA_STAT_MISS_IN_WINDOW);
964 ras_reset(ras, index);
968 ras->ras_last_readpage = index;
969 ras->ras_consecutive++;
970 ras_set_start(ras, index);
971 ras->ras_next_readahead = max(ras->ras_window_start,
972 ras->ras_next_readahead);
974 /* wait for a few pages to arrive before issuing readahead to avoid
975 * the worst overutilization */
976 if (ras->ras_consecutive == 3) {
977 ras->ras_window_len = PTLRPC_MAX_BRW_PAGES;
981 /* we need to increase the window sometimes. we'll arbitrarily
982 * do it half-way through the pages in an rpc */
983 if ((index & (PTLRPC_MAX_BRW_PAGES - 1)) ==
984 (PTLRPC_MAX_BRW_PAGES >> 1)) {
985 ras->ras_window_len += PTLRPC_MAX_BRW_PAGES;
986 ras->ras_window_len = min(ras->ras_window_len,
994 spin_unlock(&ras->ras_lock);
995 spin_unlock(&sbi->ll_lock);
999 * for now we do our readpage the same on both 2.4 and 2.5. The kernel's
1000 * read-ahead assumes it is valid to issue readpage all the way up to
1001 * i_size, but our dlm locks make that not the case. We disable the
1002 * kernel's read-ahead and do our own by walking ahead in the page cache
1003 * checking for dlm lock coverage. the main difference between 2.4 and
1004 * 2.6 is how read-ahead gets batched and issued, but we're using our own,
1005 * so they look the same.
1007 int ll_readpage(struct file *filp, struct page *page)
1009 struct ll_file_data *fd = filp->private_data;
1010 struct inode *inode = page->mapping->host;
1011 struct obd_export *exp;
1012 struct ll_async_page *llap;
1013 struct obd_io_group *oig = NULL;
1017 LASSERT(PageLocked(page));
1018 LASSERT(!PageUptodate(page));
1019 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p),offset="LPX64"\n",
1020 inode->i_ino, inode->i_generation, inode,
1021 (((obd_off)page->index) << PAGE_SHIFT));
1022 LASSERT(atomic_read(&filp->f_dentry->d_inode->i_count) > 0);
1024 rc = oig_init(&oig);
1028 exp = ll_i2dtexp(inode);
1030 GOTO(out, rc = -EINVAL);
1032 llap = llap_from_page(page, LLAP_ORIGIN_READPAGE);
1034 GOTO(out, rc = PTR_ERR(llap));
1036 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1037 ras_update(ll_i2sbi(inode), &fd->fd_ras, page->index,
1038 llap->llap_defer_uptodate);
1040 if (llap->llap_defer_uptodate) {
1041 llap->llap_ra_used = 1;
1042 rc = ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1045 obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd,
1047 LL_CDEBUG_PAGE(D_PAGE, page, "marking uptodate from defer\n");
1048 SetPageUptodate(page);
1050 GOTO(out_oig, rc = 0);
1053 rc = ll_page_matches(page, fd->fd_flags);
1055 LL_CDEBUG_PAGE(D_ERROR, page, "lock match failed: rc %d\n", rc);
1060 CWARN("ino %lu page %lu (%llu) not covered by "
1061 "a lock (mmap?). check debug logs.\n",
1062 inode->i_ino, page->index,
1063 (long long)page->index << PAGE_CACHE_SHIFT);
1066 rc = ll_issue_page_read(exp, llap, oig, 0);
1070 LL_CDEBUG_PAGE(D_PAGE, page, "queued readpage\n");
1071 if (ll_i2sbi(inode)->ll_flags & LL_SBI_READAHEAD)
1072 ll_readahead(&fd->fd_ras, exp, page->mapping, oig,
1075 rc = obd_trigger_group_io(exp, ll_i2info(inode)->lli_smd, NULL, oig);