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 pg.off = ((obd_off)page->index) << PAGE_SHIFT;
70 if (cmd == OBD_BRW_WRITE && (pg.off + PAGE_SIZE > inode->i_size))
71 pg.count = inode->i_size % PAGE_SIZE;
75 CDEBUG(D_PAGE, "%s %d bytes ino %lu at "LPU64"/"LPX64"\n",
76 cmd & OBD_BRW_WRITE ? "write" : "read", pg.count, inode->i_ino,
79 CERROR("ZERO COUNT: ino %lu: size %p:%Lu(%p:%Lu) idx %lu off "
81 inode->i_ino, inode, inode->i_size, page->mapping->host,
82 page->mapping->host->i_size, page->index, pg.off);
87 if (cmd == OBD_BRW_WRITE)
88 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
89 LPROC_LL_BRW_WRITE, pg.count);
91 lprocfs_counter_add(ll_i2sbi(inode)->ll_stats,
92 LPROC_LL_BRW_READ, pg.count);
93 rc = obd_brw(cmd, ll_i2obdexp(inode), oa, lsm, 1, &pg, NULL);
95 obdo_to_inode(inode, oa, OBD_MD_FLBLOCKS);
97 CERROR("error from obd_brw: rc = %d\n", rc);
101 /* this isn't where truncate starts. roughly:
102 * sys_truncate->ll_setattr_raw->vmtruncate->ll_truncate
103 * we grab the lock back in setattr_raw to avoid races. */
104 void ll_truncate(struct inode *inode)
106 struct lov_stripe_md *lsm = ll_i2info(inode)->lli_smd;
110 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p)\n", inode->i_ino,
111 inode->i_generation, inode);
113 /* object not yet allocated - this is handled in ll_setattr_raw */
115 CERROR("truncate on inode %lu with no objects\n", inode->i_ino);
120 oa.o_id = lsm->lsm_object_id;
121 oa.o_valid = OBD_MD_FLID;
122 obdo_from_inode(&oa, inode, OBD_MD_FLTYPE|OBD_MD_FLMODE|OBD_MD_FLATIME|
123 OBD_MD_FLMTIME | OBD_MD_FLCTIME);
125 CDEBUG(D_INFO, "calling punch for "LPX64" (all bytes after %Lu)\n",
126 oa.o_id, inode->i_size);
128 /* truncate == punch from new size to absolute end of file */
129 rc = obd_punch(ll_i2obdexp(inode), &oa, lsm, inode->i_size,
130 OBD_OBJECT_EOF, NULL);
132 CERROR("obd_truncate fails (%d) ino %lu\n", rc, inode->i_ino);
134 obdo_to_inode(inode, &oa, OBD_MD_FLSIZE | OBD_MD_FLBLOCKS |
135 OBD_MD_FLATIME | OBD_MD_FLMTIME |
142 int ll_prepare_write(struct file *file, struct page *page, unsigned from,
145 struct inode *inode = page->mapping->host;
146 struct ll_inode_info *lli = ll_i2info(inode);
147 struct lov_stripe_md *lsm = lli->lli_smd;
148 obd_off offset = ((obd_off)page->index) << PAGE_SHIFT;
154 if (!PageLocked(page))
157 if (PageUptodate(page))
160 /* Check to see if we should return -EIO right away */
163 pg.count = PAGE_SIZE;
165 rc = obd_brw(OBD_BRW_CHECK, ll_i2obdexp(inode), NULL, lsm, 1, &pg,
170 /* We're completely overwriting an existing page, so _don't_ set it up
171 * to date until commit_write */
172 if (from == 0 && to == PAGE_SIZE) {
173 POISON_PAGE(page, 0x11);
177 /* If are writing to a new page, no need to read old data.
178 * the extent locking and getattr procedures in ll_file_write have
179 * guaranteed that i_size is stable enough for our zeroing needs */
180 if (inode->i_size <= offset) {
181 memset(kmap(page), 0, PAGE_SIZE);
183 GOTO(prepare_done, rc = 0);
186 oa.o_id = lsm->lsm_object_id;
187 oa.o_mode = inode->i_mode;
188 oa.o_valid = OBD_MD_FLID | OBD_MD_FLMODE | OBD_MD_FLTYPE;
190 /* XXX could be an async ocp read.. read-ahead? */
191 rc = ll_brw(OBD_BRW_READ, inode, &oa, page, 0);
193 /* bug 1598: don't clobber blksize */
194 oa.o_valid &= ~(OBD_MD_FLSIZE | OBD_MD_FLBLKSZ);
195 obdo_refresh_inode(inode, &oa, oa.o_valid);
201 SetPageUptodate(page);
206 int ll_write_count(struct page *page)
208 struct inode *inode = page->mapping->host;
210 /* catch race with truncate */
211 if (((loff_t)page->index << PAGE_SHIFT) >= inode->i_size)
214 /* catch sub-page write at end of file */
215 if (((loff_t)page->index << PAGE_SHIFT) + PAGE_SIZE > inode->i_size)
216 return inode->i_size % PAGE_SIZE;
221 struct ll_async_page *llap_from_cookie(void *cookie)
223 struct ll_async_page *llap = cookie;
224 if (llap->llap_magic != LLAP_MAGIC)
225 return ERR_PTR(-EINVAL);
229 static int ll_ap_make_ready(void *data, int cmd)
231 struct ll_async_page *llap;
235 /* reads are always locked between queueing and completion,
236 * llite should never queue pages without _READY */
237 LASSERT(cmd != OBD_BRW_READ);
239 llap = llap_from_cookie(data);
243 page = llap->llap_page;
245 if (TryLockPage(page))
248 LL_CDEBUG_PAGE(page, "made ready\n");
249 page_cache_get(page);
251 /* if we left PageDirty we might get another writepage call
252 * in the future. list walkers are bright enough
253 * to check page dirty so we can leave it on whatever list
254 * its on. XXX also, we're called with the cli list so if
255 * we got the page cache list we'd create a lock inversion
256 * with the removepage path which gets the page lock then the
258 clear_page_dirty(page);
262 static int ll_ap_refresh_count(void *data, int cmd)
264 struct ll_async_page *llap;
267 /* readpage queues with _COUNT_STABLE, shouldn't get here. */
268 LASSERT(cmd != OBD_BRW_READ);
270 llap = llap_from_cookie(data);
272 RETURN(PTR_ERR(llap));
274 return ll_write_count(llap->llap_page);
277 void ll_inode_fill_obdo(struct inode *inode, int cmd, struct obdo *oa)
279 struct lov_stripe_md *lsm;
280 obd_flag valid_flags;
282 lsm = ll_i2info(inode)->lli_smd;
284 oa->o_id = lsm->lsm_object_id;
285 oa->o_valid = OBD_MD_FLID;
286 valid_flags = OBD_MD_FLTYPE | OBD_MD_FLATIME;
287 if (cmd == OBD_BRW_WRITE) {
288 oa->o_valid |= OBD_MD_FLIFID | OBD_MD_FLEPOCH;
289 mdc_pack_fid(obdo_fid(oa), inode->i_ino, 0, inode->i_mode);
290 oa->o_easize = ll_i2info(inode)->lli_io_epoch;
292 valid_flags |= OBD_MD_FLMTIME | OBD_MD_FLCTIME;
295 obdo_from_inode(oa, inode, valid_flags);
298 static void ll_ap_fill_obdo(void *data, int cmd, struct obdo *oa)
300 struct ll_async_page *llap;
303 llap = llap_from_cookie(data);
309 ll_inode_fill_obdo(llap->llap_page->mapping->host, cmd, oa);
313 static struct obd_async_page_ops ll_async_page_ops = {
314 .ap_make_ready = ll_ap_make_ready,
315 .ap_refresh_count = ll_ap_refresh_count,
316 .ap_fill_obdo = ll_ap_fill_obdo,
317 .ap_completion = ll_ap_completion,
320 /* XXX have the exp be an argument? */
321 struct ll_async_page *llap_from_page(struct page *page)
323 struct ll_async_page *llap;
324 struct obd_export *exp;
325 struct inode *inode = page->mapping->host;
329 if (page->private != 0) {
330 llap = (struct ll_async_page *)page->private;
331 if (llap->llap_magic != LLAP_MAGIC)
332 RETURN(ERR_PTR(-EINVAL));
336 exp = ll_i2obdexp(page->mapping->host);
338 RETURN(ERR_PTR(-EINVAL));
340 OBD_ALLOC(llap, sizeof(*llap));
341 llap->llap_magic = LLAP_MAGIC;
342 rc = obd_prep_async_page(exp, ll_i2info(inode)->lli_smd,
344 (obd_off)page->index << PAGE_SHIFT,
345 &ll_async_page_ops, llap, &llap->llap_cookie);
347 OBD_FREE(llap, sizeof(*llap));
351 CDEBUG(D_CACHE, "llap %p page %p cookie %p obj off "LPU64"\n", llap,
352 page, llap->llap_cookie, (obd_off)page->index << PAGE_SHIFT);
353 page->private = (unsigned long)llap;
354 llap->llap_page = page;
358 /* update our write count to account for i_size increases that may have
359 * happened since we've queued the page for io. */
361 /* be careful not to return success without setting the page Uptodate or
362 * the next pass through prepare_write will read in stale data from disk. */
363 int ll_commit_write(struct file *file, struct page *page, unsigned from,
366 struct inode *inode = page->mapping->host;
367 struct ll_inode_info *lli = ll_i2info(inode);
368 struct lov_stripe_md *lsm = lli->lli_smd;
369 struct obd_export *exp = NULL;
370 struct ll_async_page *llap;
375 SIGNAL_MASK_ASSERT(); /* XXX BUG 1511 */
376 LASSERT(inode == file->f_dentry->d_inode);
377 LASSERT(PageLocked(page));
379 CDEBUG(D_INODE, "inode %p is writing page %p from %d to %d at %lu\n",
380 inode, page, from, to, page->index);
382 llap = llap_from_page(page);
384 RETURN(PTR_ERR(llap));
386 /* queue a write for some time in the future the first time we
388 if (!PageDirty(page)) {
389 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
390 LPROC_LL_DIRTY_MISSES);
392 exp = ll_i2obdexp(inode);
396 rc = obd_queue_async_io(exp, lsm, NULL, llap->llap_cookie,
397 OBD_BRW_WRITE, 0, 0, 0, 0);
398 if (rc != 0) { /* async failed, try sync.. */
399 struct obd_sync_io_container osic;
402 rc = obd_queue_sync_io(exp, lsm, NULL, &osic,
404 OBD_BRW_WRITE, 0, to, 0);
408 rc = obd_trigger_sync_io(exp, lsm, NULL, &osic);
412 rc = osic_wait(&osic);
415 LL_CDEBUG_PAGE(page, "write queued\n");
416 llap->llap_queued = 1;
417 //llap_write_pending(inode, llap);
419 lprocfs_counter_incr(ll_i2sbi(inode)->ll_stats,
420 LPROC_LL_DIRTY_HITS);
423 /* put the page in the page cache, from now on ll_removepage is
424 * responsible for cleaning up the llap */
425 set_page_dirty(page);
429 /* XXX needs to be pushed down to the OSC as EOC */
430 size = (((obd_off)page->index) << PAGE_SHIFT) + to;
431 if (size > inode->i_size) {
432 inode->i_size = size;
433 /* see commentary in file.c:ll_inode_getattr() */
434 set_bit(LLI_F_PREFER_EXTENDED_SIZE, &lli->lli_flags);
436 SetPageUptodate(page);
441 /* the kernel calls us here when a page is unhashed from the page cache.
442 * the page will be locked and the kernel is holding a spinlock, so
443 * we need to be careful. we're just tearing down our book-keeping
445 void ll_removepage(struct page *page)
447 struct inode *inode = page->mapping->host;
448 struct obd_export *exp;
449 struct ll_async_page *llap;
453 LASSERT(!in_interrupt());
455 /* sync pages or failed read pages can leave pages in the page
456 * cache that don't have our data associated with them anymore */
457 if (page->private == 0) {
462 LL_CDEBUG_PAGE(page, "being evicted\n");
464 exp = ll_i2obdexp(inode);
466 CERROR("page %p ind %lu gave null export\n", page,
472 llap = llap_from_page(page);
474 CERROR("page %p ind %lu couldn't find llap: %ld\n", page,
475 page->index, PTR_ERR(llap));
480 //llap_write_complete(inode, llap);
481 rc = obd_teardown_async_page(exp, ll_i2info(inode)->lli_smd, NULL,
484 CERROR("page %p ind %lu failed: %d\n", page, page->index, rc);
486 /* this unconditional free is only safe because the page lock
487 * is providing exclusivity to memory pressure/truncate/writeback..*/
489 OBD_FREE(llap, sizeof(*llap));
493 static int ll_start_readpage(struct obd_export *exp, struct inode *inode,
496 struct ll_async_page *llap;
500 llap = llap_from_page(page);
502 RETURN(PTR_ERR(llap));
504 page_cache_get(page);
506 rc = obd_queue_async_io(exp, ll_i2info(inode)->lli_smd, NULL,
507 llap->llap_cookie, OBD_BRW_READ, 0, PAGE_SIZE,
508 0, ASYNC_READY | ASYNC_URGENT |
510 /* XXX verify that failed pages here will make their way
511 * through ->removepage.. I suspect they will. */
513 page_cache_release(page);
515 llap->llap_queued = 1;
516 LL_CDEBUG_PAGE(page, "read queued\n");
521 static void ll_start_readahead(struct obd_export *exp, struct inode *inode,
522 unsigned long first_index)
524 struct lustre_handle match_lockh = {0};
525 struct ldlm_extent page_extent;
526 unsigned long index, end_index;
528 int flags, matched, rc;
530 /* for good throughput we need to have many 'blksize' rpcs in
531 * flight per stripe, so we try to read-ahead a ridiculous amount
532 * of data. "- 3" for 8 rpcs */
533 end_index = first_index + (inode->i_blksize >> (PAGE_CACHE_SHIFT - 3));
534 if (end_index > (inode->i_size >> PAGE_CACHE_SHIFT))
535 end_index = inode->i_size >> PAGE_CACHE_SHIFT;
537 for (index = first_index + 1; index < end_index; index++) {
538 /* try to get a ref on an existing page or create a new
539 * one. if we find a locked page or lose the race
540 * with another reader we stop trying */
541 page = grab_cache_page_nowait(inode->i_mapping, index);
544 /* make sure we didn't race with other teardown/readers */
545 if (!page->mapping || Page_Uptodate(page)) {
547 page_cache_release(page);
551 /* make sure the page we're about to read is covered
552 * by a lock, stop when we go past the end of the lock */
553 page_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
554 page_extent.end = page_extent.start + PAGE_CACHE_SIZE - 1;
555 flags = LDLM_FL_CBPENDING | LDLM_FL_BLOCK_GRANTED;
556 matched = obd_match(ll_i2sbi(inode)->ll_osc_exp,
557 ll_i2info(inode)->lli_smd, LDLM_EXTENT,
558 &page_extent, sizeof(page_extent), LCK_PR,
559 &flags, inode, &match_lockh);
561 LL_CDEBUG_PAGE(page, "lock match failed\n");
563 page_cache_release(page);
567 LL_CDEBUG_PAGE(page, "didn't match a lock\n");
569 page_cache_release(page);
573 /* interestingly, we don't need to hold the lock across the IO.
574 * As long as we match the lock while the page is locked in the
575 * page cache we know that the lock's cancelation will wait for
576 * the page to be unlocked. XXX this should transition to
577 * proper association of pages and locks in the future */
578 obd_cancel(ll_i2sbi(inode)->ll_osc_exp,
579 ll_i2info(inode)->lli_smd, LCK_PR, &match_lockh);
581 rc = ll_start_readpage(exp, inode, page);
584 page_cache_release(page);
587 page_cache_release(page);
591 * for now we do our readpage the same on both 2.4 and 2.5. The kernel's
592 * read-ahead assumes it is valid to issue readpage all the way up to
593 * i_size, but our dlm locks make that not the case. We disable the
594 * kernel's read-ahead and do our own by walking ahead in the page cache
595 * checking for dlm lock coverage. the main difference between 2.4 and
596 * 2.6 is how read-ahead gets batched and issued, but we're using our own,
597 * so they look the same.
599 int ll_readpage(struct file *file, struct page *page)
601 struct inode *inode = page->mapping->host;
602 struct lustre_handle match_lockh = {0};
603 struct obd_export *exp;
604 struct ldlm_extent page_extent;
605 int flags, rc = 0, matched;
606 struct ll_sb_info *sbi = ll_i2sbi(inode);
609 LASSERT(PageLocked(page));
610 LASSERT(!PageUptodate(page));
611 CDEBUG(D_VFSTRACE, "VFS Op:inode=%lu/%u(%p),offset="LPX64"\n",
612 inode->i_ino, inode->i_generation, inode,
613 (((obd_off)page->index) << PAGE_SHIFT));
614 LASSERT(atomic_read(&file->f_dentry->d_inode->i_count) > 0);
616 if (inode->i_size <= ((obd_off)page->index) << PAGE_SHIFT) {
617 CERROR("reading beyond EOF\n");
618 memset(kmap(page), 0, PAGE_SIZE);
620 SetPageUptodate(page);
624 exp = ll_i2obdexp(inode);
626 GOTO(out, rc = -EINVAL);
628 page_extent.start = (__u64)page->index << PAGE_CACHE_SHIFT;
629 page_extent.end = page_extent.start + PAGE_CACHE_SIZE - 1;
630 flags = LDLM_FL_CBPENDING | LDLM_FL_BLOCK_GRANTED;
631 matched = obd_match(sbi->ll_osc_exp, ll_i2info(inode)->lli_smd,
632 LDLM_EXTENT, &page_extent, sizeof(page_extent),
633 LCK_PR, &flags, inode, &match_lockh);
635 GOTO(out, rc = matched);
638 static unsigned long next_print;
639 CDEBUG(D_INODE, "didn't match a lock");
640 if (time_after(jiffies, next_print)) {
641 next_print = jiffies + 30 * HZ;
642 CERROR("not covered by a lock (mmap?). check debug "
647 rc = ll_start_readpage(exp, inode, page);
648 if (rc == 0 && (sbi->ll_flags & LL_SBI_READAHEAD))
649 ll_start_readahead(exp, inode, page->index);
652 obd_cancel(ll_i2sbi(inode)->ll_osc_exp,
653 ll_i2info(inode)->lli_smd, LCK_PR, &match_lockh);