FRV: Use generic show_interrupts()
[cris-mirror.git] / fs / xfs / linux-2.6 / xfs_aops.c
blob52dbd14260ba691fdbf9cc46b1e46d13fc461e9e
1 /*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 #include "xfs.h"
19 #include "xfs_bit.h"
20 #include "xfs_log.h"
21 #include "xfs_inum.h"
22 #include "xfs_sb.h"
23 #include "xfs_ag.h"
24 #include "xfs_trans.h"
25 #include "xfs_mount.h"
26 #include "xfs_bmap_btree.h"
27 #include "xfs_dinode.h"
28 #include "xfs_inode.h"
29 #include "xfs_alloc.h"
30 #include "xfs_error.h"
31 #include "xfs_rw.h"
32 #include "xfs_iomap.h"
33 #include "xfs_vnodeops.h"
34 #include "xfs_trace.h"
35 #include "xfs_bmap.h"
36 #include <linux/gfp.h>
37 #include <linux/mpage.h>
38 #include <linux/pagevec.h>
39 #include <linux/writeback.h>
43 * Prime number of hash buckets since address is used as the key.
45 #define NVSYNC 37
46 #define to_ioend_wq(v) (&xfs_ioend_wq[((unsigned long)v) % NVSYNC])
47 static wait_queue_head_t xfs_ioend_wq[NVSYNC];
49 void __init
50 xfs_ioend_init(void)
52 int i;
54 for (i = 0; i < NVSYNC; i++)
55 init_waitqueue_head(&xfs_ioend_wq[i]);
58 void
59 xfs_ioend_wait(
60 xfs_inode_t *ip)
62 wait_queue_head_t *wq = to_ioend_wq(ip);
64 wait_event(*wq, (atomic_read(&ip->i_iocount) == 0));
67 STATIC void
68 xfs_ioend_wake(
69 xfs_inode_t *ip)
71 if (atomic_dec_and_test(&ip->i_iocount))
72 wake_up(to_ioend_wq(ip));
75 void
76 xfs_count_page_state(
77 struct page *page,
78 int *delalloc,
79 int *unwritten)
81 struct buffer_head *bh, *head;
83 *delalloc = *unwritten = 0;
85 bh = head = page_buffers(page);
86 do {
87 if (buffer_unwritten(bh))
88 (*unwritten) = 1;
89 else if (buffer_delay(bh))
90 (*delalloc) = 1;
91 } while ((bh = bh->b_this_page) != head);
94 STATIC struct block_device *
95 xfs_find_bdev_for_inode(
96 struct inode *inode)
98 struct xfs_inode *ip = XFS_I(inode);
99 struct xfs_mount *mp = ip->i_mount;
101 if (XFS_IS_REALTIME_INODE(ip))
102 return mp->m_rtdev_targp->bt_bdev;
103 else
104 return mp->m_ddev_targp->bt_bdev;
108 * We're now finished for good with this ioend structure.
109 * Update the page state via the associated buffer_heads,
110 * release holds on the inode and bio, and finally free
111 * up memory. Do not use the ioend after this.
113 STATIC void
114 xfs_destroy_ioend(
115 xfs_ioend_t *ioend)
117 struct buffer_head *bh, *next;
118 struct xfs_inode *ip = XFS_I(ioend->io_inode);
120 for (bh = ioend->io_buffer_head; bh; bh = next) {
121 next = bh->b_private;
122 bh->b_end_io(bh, !ioend->io_error);
126 * Volume managers supporting multiple paths can send back ENODEV
127 * when the final path disappears. In this case continuing to fill
128 * the page cache with dirty data which cannot be written out is
129 * evil, so prevent that.
131 if (unlikely(ioend->io_error == -ENODEV)) {
132 xfs_do_force_shutdown(ip->i_mount, SHUTDOWN_DEVICE_REQ,
133 __FILE__, __LINE__);
136 xfs_ioend_wake(ip);
137 mempool_free(ioend, xfs_ioend_pool);
141 * If the end of the current ioend is beyond the current EOF,
142 * return the new EOF value, otherwise zero.
144 STATIC xfs_fsize_t
145 xfs_ioend_new_eof(
146 xfs_ioend_t *ioend)
148 xfs_inode_t *ip = XFS_I(ioend->io_inode);
149 xfs_fsize_t isize;
150 xfs_fsize_t bsize;
152 bsize = ioend->io_offset + ioend->io_size;
153 isize = MAX(ip->i_size, ip->i_new_size);
154 isize = MIN(isize, bsize);
155 return isize > ip->i_d.di_size ? isize : 0;
159 * Update on-disk file size now that data has been written to disk. The
160 * current in-memory file size is i_size. If a write is beyond eof i_new_size
161 * will be the intended file size until i_size is updated. If this write does
162 * not extend all the way to the valid file size then restrict this update to
163 * the end of the write.
165 * This function does not block as blocking on the inode lock in IO completion
166 * can lead to IO completion order dependency deadlocks.. If it can't get the
167 * inode ilock it will return EAGAIN. Callers must handle this.
169 STATIC int
170 xfs_setfilesize(
171 xfs_ioend_t *ioend)
173 xfs_inode_t *ip = XFS_I(ioend->io_inode);
174 xfs_fsize_t isize;
176 if (unlikely(ioend->io_error))
177 return 0;
179 if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
180 return EAGAIN;
182 isize = xfs_ioend_new_eof(ioend);
183 if (isize) {
184 ip->i_d.di_size = isize;
185 xfs_mark_inode_dirty(ip);
188 xfs_iunlock(ip, XFS_ILOCK_EXCL);
189 return 0;
193 * Schedule IO completion handling on the final put of an ioend.
195 STATIC void
196 xfs_finish_ioend(
197 struct xfs_ioend *ioend)
199 if (atomic_dec_and_test(&ioend->io_remaining)) {
200 if (ioend->io_type == IO_UNWRITTEN)
201 queue_work(xfsconvertd_workqueue, &ioend->io_work);
202 else
203 queue_work(xfsdatad_workqueue, &ioend->io_work);
208 * IO write completion.
210 STATIC void
211 xfs_end_io(
212 struct work_struct *work)
214 xfs_ioend_t *ioend = container_of(work, xfs_ioend_t, io_work);
215 struct xfs_inode *ip = XFS_I(ioend->io_inode);
216 int error = 0;
219 * For unwritten extents we need to issue transactions to convert a
220 * range to normal written extens after the data I/O has finished.
222 if (ioend->io_type == IO_UNWRITTEN &&
223 likely(!ioend->io_error && !XFS_FORCED_SHUTDOWN(ip->i_mount))) {
225 error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
226 ioend->io_size);
227 if (error)
228 ioend->io_error = error;
232 * We might have to update the on-disk file size after extending
233 * writes.
235 error = xfs_setfilesize(ioend);
236 ASSERT(!error || error == EAGAIN);
239 * If we didn't complete processing of the ioend, requeue it to the
240 * tail of the workqueue for another attempt later. Otherwise destroy
241 * it.
243 if (error == EAGAIN) {
244 atomic_inc(&ioend->io_remaining);
245 xfs_finish_ioend(ioend);
246 /* ensure we don't spin on blocked ioends */
247 delay(1);
248 } else {
249 if (ioend->io_iocb)
250 aio_complete(ioend->io_iocb, ioend->io_result, 0);
251 xfs_destroy_ioend(ioend);
256 * Call IO completion handling in caller context on the final put of an ioend.
258 STATIC void
259 xfs_finish_ioend_sync(
260 struct xfs_ioend *ioend)
262 if (atomic_dec_and_test(&ioend->io_remaining))
263 xfs_end_io(&ioend->io_work);
267 * Allocate and initialise an IO completion structure.
268 * We need to track unwritten extent write completion here initially.
269 * We'll need to extend this for updating the ondisk inode size later
270 * (vs. incore size).
272 STATIC xfs_ioend_t *
273 xfs_alloc_ioend(
274 struct inode *inode,
275 unsigned int type)
277 xfs_ioend_t *ioend;
279 ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
282 * Set the count to 1 initially, which will prevent an I/O
283 * completion callback from happening before we have started
284 * all the I/O from calling the completion routine too early.
286 atomic_set(&ioend->io_remaining, 1);
287 ioend->io_error = 0;
288 ioend->io_list = NULL;
289 ioend->io_type = type;
290 ioend->io_inode = inode;
291 ioend->io_buffer_head = NULL;
292 ioend->io_buffer_tail = NULL;
293 atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);
294 ioend->io_offset = 0;
295 ioend->io_size = 0;
296 ioend->io_iocb = NULL;
297 ioend->io_result = 0;
299 INIT_WORK(&ioend->io_work, xfs_end_io);
300 return ioend;
303 STATIC int
304 xfs_map_blocks(
305 struct inode *inode,
306 loff_t offset,
307 struct xfs_bmbt_irec *imap,
308 int type,
309 int nonblocking)
311 struct xfs_inode *ip = XFS_I(inode);
312 struct xfs_mount *mp = ip->i_mount;
313 ssize_t count = 1 << inode->i_blkbits;
314 xfs_fileoff_t offset_fsb, end_fsb;
315 int error = 0;
316 int bmapi_flags = XFS_BMAPI_ENTIRE;
317 int nimaps = 1;
319 if (XFS_FORCED_SHUTDOWN(mp))
320 return -XFS_ERROR(EIO);
322 if (type == IO_UNWRITTEN)
323 bmapi_flags |= XFS_BMAPI_IGSTATE;
325 if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {
326 if (nonblocking)
327 return -XFS_ERROR(EAGAIN);
328 xfs_ilock(ip, XFS_ILOCK_SHARED);
331 ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
332 (ip->i_df.if_flags & XFS_IFEXTENTS));
333 ASSERT(offset <= mp->m_maxioffset);
335 if (offset + count > mp->m_maxioffset)
336 count = mp->m_maxioffset - offset;
337 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
338 offset_fsb = XFS_B_TO_FSBT(mp, offset);
339 error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
340 bmapi_flags, NULL, 0, imap, &nimaps, NULL);
341 xfs_iunlock(ip, XFS_ILOCK_SHARED);
343 if (error)
344 return -XFS_ERROR(error);
346 if (type == IO_DELALLOC &&
347 (!nimaps || isnullstartblock(imap->br_startblock))) {
348 error = xfs_iomap_write_allocate(ip, offset, count, imap);
349 if (!error)
350 trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
351 return -XFS_ERROR(error);
354 #ifdef DEBUG
355 if (type == IO_UNWRITTEN) {
356 ASSERT(nimaps);
357 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
358 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
360 #endif
361 if (nimaps)
362 trace_xfs_map_blocks_found(ip, offset, count, type, imap);
363 return 0;
366 STATIC int
367 xfs_imap_valid(
368 struct inode *inode,
369 struct xfs_bmbt_irec *imap,
370 xfs_off_t offset)
372 offset >>= inode->i_blkbits;
374 return offset >= imap->br_startoff &&
375 offset < imap->br_startoff + imap->br_blockcount;
379 * BIO completion handler for buffered IO.
381 STATIC void
382 xfs_end_bio(
383 struct bio *bio,
384 int error)
386 xfs_ioend_t *ioend = bio->bi_private;
388 ASSERT(atomic_read(&bio->bi_cnt) >= 1);
389 ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
391 /* Toss bio and pass work off to an xfsdatad thread */
392 bio->bi_private = NULL;
393 bio->bi_end_io = NULL;
394 bio_put(bio);
396 xfs_finish_ioend(ioend);
399 STATIC void
400 xfs_submit_ioend_bio(
401 struct writeback_control *wbc,
402 xfs_ioend_t *ioend,
403 struct bio *bio)
405 atomic_inc(&ioend->io_remaining);
406 bio->bi_private = ioend;
407 bio->bi_end_io = xfs_end_bio;
410 * If the I/O is beyond EOF we mark the inode dirty immediately
411 * but don't update the inode size until I/O completion.
413 if (xfs_ioend_new_eof(ioend))
414 xfs_mark_inode_dirty(XFS_I(ioend->io_inode));
416 submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio);
419 STATIC struct bio *
420 xfs_alloc_ioend_bio(
421 struct buffer_head *bh)
423 int nvecs = bio_get_nr_vecs(bh->b_bdev);
424 struct bio *bio = bio_alloc(GFP_NOIO, nvecs);
426 ASSERT(bio->bi_private == NULL);
427 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
428 bio->bi_bdev = bh->b_bdev;
429 return bio;
432 STATIC void
433 xfs_start_buffer_writeback(
434 struct buffer_head *bh)
436 ASSERT(buffer_mapped(bh));
437 ASSERT(buffer_locked(bh));
438 ASSERT(!buffer_delay(bh));
439 ASSERT(!buffer_unwritten(bh));
441 mark_buffer_async_write(bh);
442 set_buffer_uptodate(bh);
443 clear_buffer_dirty(bh);
446 STATIC void
447 xfs_start_page_writeback(
448 struct page *page,
449 int clear_dirty,
450 int buffers)
452 ASSERT(PageLocked(page));
453 ASSERT(!PageWriteback(page));
454 if (clear_dirty)
455 clear_page_dirty_for_io(page);
456 set_page_writeback(page);
457 unlock_page(page);
458 /* If no buffers on the page are to be written, finish it here */
459 if (!buffers)
460 end_page_writeback(page);
463 static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
465 return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
469 * Submit all of the bios for all of the ioends we have saved up, covering the
470 * initial writepage page and also any probed pages.
472 * Because we may have multiple ioends spanning a page, we need to start
473 * writeback on all the buffers before we submit them for I/O. If we mark the
474 * buffers as we got, then we can end up with a page that only has buffers
475 * marked async write and I/O complete on can occur before we mark the other
476 * buffers async write.
478 * The end result of this is that we trip a bug in end_page_writeback() because
479 * we call it twice for the one page as the code in end_buffer_async_write()
480 * assumes that all buffers on the page are started at the same time.
482 * The fix is two passes across the ioend list - one to start writeback on the
483 * buffer_heads, and then submit them for I/O on the second pass.
485 STATIC void
486 xfs_submit_ioend(
487 struct writeback_control *wbc,
488 xfs_ioend_t *ioend)
490 xfs_ioend_t *head = ioend;
491 xfs_ioend_t *next;
492 struct buffer_head *bh;
493 struct bio *bio;
494 sector_t lastblock = 0;
496 /* Pass 1 - start writeback */
497 do {
498 next = ioend->io_list;
499 for (bh = ioend->io_buffer_head; bh; bh = bh->b_private)
500 xfs_start_buffer_writeback(bh);
501 } while ((ioend = next) != NULL);
503 /* Pass 2 - submit I/O */
504 ioend = head;
505 do {
506 next = ioend->io_list;
507 bio = NULL;
509 for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
511 if (!bio) {
512 retry:
513 bio = xfs_alloc_ioend_bio(bh);
514 } else if (bh->b_blocknr != lastblock + 1) {
515 xfs_submit_ioend_bio(wbc, ioend, bio);
516 goto retry;
519 if (bio_add_buffer(bio, bh) != bh->b_size) {
520 xfs_submit_ioend_bio(wbc, ioend, bio);
521 goto retry;
524 lastblock = bh->b_blocknr;
526 if (bio)
527 xfs_submit_ioend_bio(wbc, ioend, bio);
528 xfs_finish_ioend(ioend);
529 } while ((ioend = next) != NULL);
533 * Cancel submission of all buffer_heads so far in this endio.
534 * Toss the endio too. Only ever called for the initial page
535 * in a writepage request, so only ever one page.
537 STATIC void
538 xfs_cancel_ioend(
539 xfs_ioend_t *ioend)
541 xfs_ioend_t *next;
542 struct buffer_head *bh, *next_bh;
544 do {
545 next = ioend->io_list;
546 bh = ioend->io_buffer_head;
547 do {
548 next_bh = bh->b_private;
549 clear_buffer_async_write(bh);
550 unlock_buffer(bh);
551 } while ((bh = next_bh) != NULL);
553 xfs_ioend_wake(XFS_I(ioend->io_inode));
554 mempool_free(ioend, xfs_ioend_pool);
555 } while ((ioend = next) != NULL);
559 * Test to see if we've been building up a completion structure for
560 * earlier buffers -- if so, we try to append to this ioend if we
561 * can, otherwise we finish off any current ioend and start another.
562 * Return true if we've finished the given ioend.
564 STATIC void
565 xfs_add_to_ioend(
566 struct inode *inode,
567 struct buffer_head *bh,
568 xfs_off_t offset,
569 unsigned int type,
570 xfs_ioend_t **result,
571 int need_ioend)
573 xfs_ioend_t *ioend = *result;
575 if (!ioend || need_ioend || type != ioend->io_type) {
576 xfs_ioend_t *previous = *result;
578 ioend = xfs_alloc_ioend(inode, type);
579 ioend->io_offset = offset;
580 ioend->io_buffer_head = bh;
581 ioend->io_buffer_tail = bh;
582 if (previous)
583 previous->io_list = ioend;
584 *result = ioend;
585 } else {
586 ioend->io_buffer_tail->b_private = bh;
587 ioend->io_buffer_tail = bh;
590 bh->b_private = NULL;
591 ioend->io_size += bh->b_size;
594 STATIC void
595 xfs_map_buffer(
596 struct inode *inode,
597 struct buffer_head *bh,
598 struct xfs_bmbt_irec *imap,
599 xfs_off_t offset)
601 sector_t bn;
602 struct xfs_mount *m = XFS_I(inode)->i_mount;
603 xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
604 xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
606 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
607 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
609 bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
610 ((offset - iomap_offset) >> inode->i_blkbits);
612 ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
614 bh->b_blocknr = bn;
615 set_buffer_mapped(bh);
618 STATIC void
619 xfs_map_at_offset(
620 struct inode *inode,
621 struct buffer_head *bh,
622 struct xfs_bmbt_irec *imap,
623 xfs_off_t offset)
625 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
626 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
628 xfs_map_buffer(inode, bh, imap, offset);
629 set_buffer_mapped(bh);
630 clear_buffer_delay(bh);
631 clear_buffer_unwritten(bh);
635 * Test if a given page is suitable for writing as part of an unwritten
636 * or delayed allocate extent.
638 STATIC int
639 xfs_is_delayed_page(
640 struct page *page,
641 unsigned int type)
643 if (PageWriteback(page))
644 return 0;
646 if (page->mapping && page_has_buffers(page)) {
647 struct buffer_head *bh, *head;
648 int acceptable = 0;
650 bh = head = page_buffers(page);
651 do {
652 if (buffer_unwritten(bh))
653 acceptable = (type == IO_UNWRITTEN);
654 else if (buffer_delay(bh))
655 acceptable = (type == IO_DELALLOC);
656 else if (buffer_dirty(bh) && buffer_mapped(bh))
657 acceptable = (type == IO_OVERWRITE);
658 else
659 break;
660 } while ((bh = bh->b_this_page) != head);
662 if (acceptable)
663 return 1;
666 return 0;
670 * Allocate & map buffers for page given the extent map. Write it out.
671 * except for the original page of a writepage, this is called on
672 * delalloc/unwritten pages only, for the original page it is possible
673 * that the page has no mapping at all.
675 STATIC int
676 xfs_convert_page(
677 struct inode *inode,
678 struct page *page,
679 loff_t tindex,
680 struct xfs_bmbt_irec *imap,
681 xfs_ioend_t **ioendp,
682 struct writeback_control *wbc)
684 struct buffer_head *bh, *head;
685 xfs_off_t end_offset;
686 unsigned long p_offset;
687 unsigned int type;
688 int len, page_dirty;
689 int count = 0, done = 0, uptodate = 1;
690 xfs_off_t offset = page_offset(page);
692 if (page->index != tindex)
693 goto fail;
694 if (!trylock_page(page))
695 goto fail;
696 if (PageWriteback(page))
697 goto fail_unlock_page;
698 if (page->mapping != inode->i_mapping)
699 goto fail_unlock_page;
700 if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
701 goto fail_unlock_page;
704 * page_dirty is initially a count of buffers on the page before
705 * EOF and is decremented as we move each into a cleanable state.
707 * Derivation:
709 * End offset is the highest offset that this page should represent.
710 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
711 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
712 * hence give us the correct page_dirty count. On any other page,
713 * it will be zero and in that case we need page_dirty to be the
714 * count of buffers on the page.
716 end_offset = min_t(unsigned long long,
717 (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
718 i_size_read(inode));
720 len = 1 << inode->i_blkbits;
721 p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
722 PAGE_CACHE_SIZE);
723 p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
724 page_dirty = p_offset / len;
726 bh = head = page_buffers(page);
727 do {
728 if (offset >= end_offset)
729 break;
730 if (!buffer_uptodate(bh))
731 uptodate = 0;
732 if (!(PageUptodate(page) || buffer_uptodate(bh))) {
733 done = 1;
734 continue;
737 if (buffer_unwritten(bh) || buffer_delay(bh) ||
738 buffer_mapped(bh)) {
739 if (buffer_unwritten(bh))
740 type = IO_UNWRITTEN;
741 else if (buffer_delay(bh))
742 type = IO_DELALLOC;
743 else
744 type = IO_OVERWRITE;
746 if (!xfs_imap_valid(inode, imap, offset)) {
747 done = 1;
748 continue;
751 lock_buffer(bh);
752 if (type != IO_OVERWRITE)
753 xfs_map_at_offset(inode, bh, imap, offset);
754 xfs_add_to_ioend(inode, bh, offset, type,
755 ioendp, done);
757 page_dirty--;
758 count++;
759 } else {
760 done = 1;
762 } while (offset += len, (bh = bh->b_this_page) != head);
764 if (uptodate && bh == head)
765 SetPageUptodate(page);
767 if (count) {
768 if (--wbc->nr_to_write <= 0 &&
769 wbc->sync_mode == WB_SYNC_NONE)
770 done = 1;
772 xfs_start_page_writeback(page, !page_dirty, count);
774 return done;
775 fail_unlock_page:
776 unlock_page(page);
777 fail:
778 return 1;
782 * Convert & write out a cluster of pages in the same extent as defined
783 * by mp and following the start page.
785 STATIC void
786 xfs_cluster_write(
787 struct inode *inode,
788 pgoff_t tindex,
789 struct xfs_bmbt_irec *imap,
790 xfs_ioend_t **ioendp,
791 struct writeback_control *wbc,
792 pgoff_t tlast)
794 struct pagevec pvec;
795 int done = 0, i;
797 pagevec_init(&pvec, 0);
798 while (!done && tindex <= tlast) {
799 unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
801 if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
802 break;
804 for (i = 0; i < pagevec_count(&pvec); i++) {
805 done = xfs_convert_page(inode, pvec.pages[i], tindex++,
806 imap, ioendp, wbc);
807 if (done)
808 break;
811 pagevec_release(&pvec);
812 cond_resched();
816 STATIC void
817 xfs_vm_invalidatepage(
818 struct page *page,
819 unsigned long offset)
821 trace_xfs_invalidatepage(page->mapping->host, page, offset);
822 block_invalidatepage(page, offset);
826 * If the page has delalloc buffers on it, we need to punch them out before we
827 * invalidate the page. If we don't, we leave a stale delalloc mapping on the
828 * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
829 * is done on that same region - the delalloc extent is returned when none is
830 * supposed to be there.
832 * We prevent this by truncating away the delalloc regions on the page before
833 * invalidating it. Because they are delalloc, we can do this without needing a
834 * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
835 * truncation without a transaction as there is no space left for block
836 * reservation (typically why we see a ENOSPC in writeback).
838 * This is not a performance critical path, so for now just do the punching a
839 * buffer head at a time.
841 STATIC void
842 xfs_aops_discard_page(
843 struct page *page)
845 struct inode *inode = page->mapping->host;
846 struct xfs_inode *ip = XFS_I(inode);
847 struct buffer_head *bh, *head;
848 loff_t offset = page_offset(page);
850 if (!xfs_is_delayed_page(page, IO_DELALLOC))
851 goto out_invalidate;
853 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
854 goto out_invalidate;
856 xfs_alert(ip->i_mount,
857 "page discard on page %p, inode 0x%llx, offset %llu.",
858 page, ip->i_ino, offset);
860 xfs_ilock(ip, XFS_ILOCK_EXCL);
861 bh = head = page_buffers(page);
862 do {
863 int error;
864 xfs_fileoff_t start_fsb;
866 if (!buffer_delay(bh))
867 goto next_buffer;
869 start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
870 error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
871 if (error) {
872 /* something screwed, just bail */
873 if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
874 xfs_alert(ip->i_mount,
875 "page discard unable to remove delalloc mapping.");
877 break;
879 next_buffer:
880 offset += 1 << inode->i_blkbits;
882 } while ((bh = bh->b_this_page) != head);
884 xfs_iunlock(ip, XFS_ILOCK_EXCL);
885 out_invalidate:
886 xfs_vm_invalidatepage(page, 0);
887 return;
891 * Write out a dirty page.
893 * For delalloc space on the page we need to allocate space and flush it.
894 * For unwritten space on the page we need to start the conversion to
895 * regular allocated space.
896 * For any other dirty buffer heads on the page we should flush them.
898 * If we detect that a transaction would be required to flush the page, we
899 * have to check the process flags first, if we are already in a transaction
900 * or disk I/O during allocations is off, we need to fail the writepage and
901 * redirty the page.
903 STATIC int
904 xfs_vm_writepage(
905 struct page *page,
906 struct writeback_control *wbc)
908 struct inode *inode = page->mapping->host;
909 int delalloc, unwritten;
910 struct buffer_head *bh, *head;
911 struct xfs_bmbt_irec imap;
912 xfs_ioend_t *ioend = NULL, *iohead = NULL;
913 loff_t offset;
914 unsigned int type;
915 __uint64_t end_offset;
916 pgoff_t end_index, last_index;
917 ssize_t len;
918 int err, imap_valid = 0, uptodate = 1;
919 int count = 0;
920 int nonblocking = 0;
922 trace_xfs_writepage(inode, page, 0);
924 ASSERT(page_has_buffers(page));
927 * Refuse to write the page out if we are called from reclaim context.
929 * This avoids stack overflows when called from deeply used stacks in
930 * random callers for direct reclaim or memcg reclaim. We explicitly
931 * allow reclaim from kswapd as the stack usage there is relatively low.
933 * This should really be done by the core VM, but until that happens
934 * filesystems like XFS, btrfs and ext4 have to take care of this
935 * by themselves.
937 if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
938 goto redirty;
941 * We need a transaction if there are delalloc or unwritten buffers
942 * on the page.
944 * If we need a transaction and the process flags say we are already
945 * in a transaction, or no IO is allowed then mark the page dirty
946 * again and leave the page as is.
948 xfs_count_page_state(page, &delalloc, &unwritten);
949 if ((current->flags & PF_FSTRANS) && (delalloc || unwritten))
950 goto redirty;
952 /* Is this page beyond the end of the file? */
953 offset = i_size_read(inode);
954 end_index = offset >> PAGE_CACHE_SHIFT;
955 last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
956 if (page->index >= end_index) {
957 if ((page->index >= end_index + 1) ||
958 !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
959 unlock_page(page);
960 return 0;
964 end_offset = min_t(unsigned long long,
965 (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
966 offset);
967 len = 1 << inode->i_blkbits;
969 bh = head = page_buffers(page);
970 offset = page_offset(page);
971 type = IO_OVERWRITE;
973 if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
974 nonblocking = 1;
976 do {
977 int new_ioend = 0;
979 if (offset >= end_offset)
980 break;
981 if (!buffer_uptodate(bh))
982 uptodate = 0;
985 * set_page_dirty dirties all buffers in a page, independent
986 * of their state. The dirty state however is entirely
987 * meaningless for holes (!mapped && uptodate), so skip
988 * buffers covering holes here.
990 if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
991 imap_valid = 0;
992 continue;
995 if (buffer_unwritten(bh)) {
996 if (type != IO_UNWRITTEN) {
997 type = IO_UNWRITTEN;
998 imap_valid = 0;
1000 } else if (buffer_delay(bh)) {
1001 if (type != IO_DELALLOC) {
1002 type = IO_DELALLOC;
1003 imap_valid = 0;
1005 } else if (buffer_uptodate(bh)) {
1006 if (type != IO_OVERWRITE) {
1007 type = IO_OVERWRITE;
1008 imap_valid = 0;
1010 } else {
1011 if (PageUptodate(page)) {
1012 ASSERT(buffer_mapped(bh));
1013 imap_valid = 0;
1015 continue;
1018 if (imap_valid)
1019 imap_valid = xfs_imap_valid(inode, &imap, offset);
1020 if (!imap_valid) {
1022 * If we didn't have a valid mapping then we need to
1023 * put the new mapping into a separate ioend structure.
1024 * This ensures non-contiguous extents always have
1025 * separate ioends, which is particularly important
1026 * for unwritten extent conversion at I/O completion
1027 * time.
1029 new_ioend = 1;
1030 err = xfs_map_blocks(inode, offset, &imap, type,
1031 nonblocking);
1032 if (err)
1033 goto error;
1034 imap_valid = xfs_imap_valid(inode, &imap, offset);
1036 if (imap_valid) {
1037 lock_buffer(bh);
1038 if (type != IO_OVERWRITE)
1039 xfs_map_at_offset(inode, bh, &imap, offset);
1040 xfs_add_to_ioend(inode, bh, offset, type, &ioend,
1041 new_ioend);
1042 count++;
1045 if (!iohead)
1046 iohead = ioend;
1048 } while (offset += len, ((bh = bh->b_this_page) != head));
1050 if (uptodate && bh == head)
1051 SetPageUptodate(page);
1053 xfs_start_page_writeback(page, 1, count);
1055 if (ioend && imap_valid) {
1056 xfs_off_t end_index;
1058 end_index = imap.br_startoff + imap.br_blockcount;
1060 /* to bytes */
1061 end_index <<= inode->i_blkbits;
1063 /* to pages */
1064 end_index = (end_index - 1) >> PAGE_CACHE_SHIFT;
1066 /* check against file size */
1067 if (end_index > last_index)
1068 end_index = last_index;
1070 xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
1071 wbc, end_index);
1074 if (iohead)
1075 xfs_submit_ioend(wbc, iohead);
1077 return 0;
1079 error:
1080 if (iohead)
1081 xfs_cancel_ioend(iohead);
1083 if (err == -EAGAIN)
1084 goto redirty;
1086 xfs_aops_discard_page(page);
1087 ClearPageUptodate(page);
1088 unlock_page(page);
1089 return err;
1091 redirty:
1092 redirty_page_for_writepage(wbc, page);
1093 unlock_page(page);
1094 return 0;
1097 STATIC int
1098 xfs_vm_writepages(
1099 struct address_space *mapping,
1100 struct writeback_control *wbc)
1102 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
1103 return generic_writepages(mapping, wbc);
1107 * Called to move a page into cleanable state - and from there
1108 * to be released. The page should already be clean. We always
1109 * have buffer heads in this call.
1111 * Returns 1 if the page is ok to release, 0 otherwise.
1113 STATIC int
1114 xfs_vm_releasepage(
1115 struct page *page,
1116 gfp_t gfp_mask)
1118 int delalloc, unwritten;
1120 trace_xfs_releasepage(page->mapping->host, page, 0);
1122 xfs_count_page_state(page, &delalloc, &unwritten);
1124 if (WARN_ON(delalloc))
1125 return 0;
1126 if (WARN_ON(unwritten))
1127 return 0;
1129 return try_to_free_buffers(page);
1132 STATIC int
1133 __xfs_get_blocks(
1134 struct inode *inode,
1135 sector_t iblock,
1136 struct buffer_head *bh_result,
1137 int create,
1138 int direct)
1140 struct xfs_inode *ip = XFS_I(inode);
1141 struct xfs_mount *mp = ip->i_mount;
1142 xfs_fileoff_t offset_fsb, end_fsb;
1143 int error = 0;
1144 int lockmode = 0;
1145 struct xfs_bmbt_irec imap;
1146 int nimaps = 1;
1147 xfs_off_t offset;
1148 ssize_t size;
1149 int new = 0;
1151 if (XFS_FORCED_SHUTDOWN(mp))
1152 return -XFS_ERROR(EIO);
1154 offset = (xfs_off_t)iblock << inode->i_blkbits;
1155 ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
1156 size = bh_result->b_size;
1158 if (!create && direct && offset >= i_size_read(inode))
1159 return 0;
1161 if (create) {
1162 lockmode = XFS_ILOCK_EXCL;
1163 xfs_ilock(ip, lockmode);
1164 } else {
1165 lockmode = xfs_ilock_map_shared(ip);
1168 ASSERT(offset <= mp->m_maxioffset);
1169 if (offset + size > mp->m_maxioffset)
1170 size = mp->m_maxioffset - offset;
1171 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
1172 offset_fsb = XFS_B_TO_FSBT(mp, offset);
1174 error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
1175 XFS_BMAPI_ENTIRE, NULL, 0, &imap, &nimaps, NULL);
1176 if (error)
1177 goto out_unlock;
1179 if (create &&
1180 (!nimaps ||
1181 (imap.br_startblock == HOLESTARTBLOCK ||
1182 imap.br_startblock == DELAYSTARTBLOCK))) {
1183 if (direct) {
1184 error = xfs_iomap_write_direct(ip, offset, size,
1185 &imap, nimaps);
1186 } else {
1187 error = xfs_iomap_write_delay(ip, offset, size, &imap);
1189 if (error)
1190 goto out_unlock;
1192 trace_xfs_get_blocks_alloc(ip, offset, size, 0, &imap);
1193 } else if (nimaps) {
1194 trace_xfs_get_blocks_found(ip, offset, size, 0, &imap);
1195 } else {
1196 trace_xfs_get_blocks_notfound(ip, offset, size);
1197 goto out_unlock;
1199 xfs_iunlock(ip, lockmode);
1201 if (imap.br_startblock != HOLESTARTBLOCK &&
1202 imap.br_startblock != DELAYSTARTBLOCK) {
1204 * For unwritten extents do not report a disk address on
1205 * the read case (treat as if we're reading into a hole).
1207 if (create || !ISUNWRITTEN(&imap))
1208 xfs_map_buffer(inode, bh_result, &imap, offset);
1209 if (create && ISUNWRITTEN(&imap)) {
1210 if (direct)
1211 bh_result->b_private = inode;
1212 set_buffer_unwritten(bh_result);
1217 * If this is a realtime file, data may be on a different device.
1218 * to that pointed to from the buffer_head b_bdev currently.
1220 bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
1223 * If we previously allocated a block out beyond eof and we are now
1224 * coming back to use it then we will need to flag it as new even if it
1225 * has a disk address.
1227 * With sub-block writes into unwritten extents we also need to mark
1228 * the buffer as new so that the unwritten parts of the buffer gets
1229 * correctly zeroed.
1231 if (create &&
1232 ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1233 (offset >= i_size_read(inode)) ||
1234 (new || ISUNWRITTEN(&imap))))
1235 set_buffer_new(bh_result);
1237 if (imap.br_startblock == DELAYSTARTBLOCK) {
1238 BUG_ON(direct);
1239 if (create) {
1240 set_buffer_uptodate(bh_result);
1241 set_buffer_mapped(bh_result);
1242 set_buffer_delay(bh_result);
1247 * If this is O_DIRECT or the mpage code calling tell them how large
1248 * the mapping is, so that we can avoid repeated get_blocks calls.
1250 if (direct || size > (1 << inode->i_blkbits)) {
1251 xfs_off_t mapping_size;
1253 mapping_size = imap.br_startoff + imap.br_blockcount - iblock;
1254 mapping_size <<= inode->i_blkbits;
1256 ASSERT(mapping_size > 0);
1257 if (mapping_size > size)
1258 mapping_size = size;
1259 if (mapping_size > LONG_MAX)
1260 mapping_size = LONG_MAX;
1262 bh_result->b_size = mapping_size;
1265 return 0;
1267 out_unlock:
1268 xfs_iunlock(ip, lockmode);
1269 return -error;
1273 xfs_get_blocks(
1274 struct inode *inode,
1275 sector_t iblock,
1276 struct buffer_head *bh_result,
1277 int create)
1279 return __xfs_get_blocks(inode, iblock, bh_result, create, 0);
1282 STATIC int
1283 xfs_get_blocks_direct(
1284 struct inode *inode,
1285 sector_t iblock,
1286 struct buffer_head *bh_result,
1287 int create)
1289 return __xfs_get_blocks(inode, iblock, bh_result, create, 1);
1293 * Complete a direct I/O write request.
1295 * If the private argument is non-NULL __xfs_get_blocks signals us that we
1296 * need to issue a transaction to convert the range from unwritten to written
1297 * extents. In case this is regular synchronous I/O we just call xfs_end_io
1298 * to do this and we are done. But in case this was a successfull AIO
1299 * request this handler is called from interrupt context, from which we
1300 * can't start transactions. In that case offload the I/O completion to
1301 * the workqueues we also use for buffered I/O completion.
1303 STATIC void
1304 xfs_end_io_direct_write(
1305 struct kiocb *iocb,
1306 loff_t offset,
1307 ssize_t size,
1308 void *private,
1309 int ret,
1310 bool is_async)
1312 struct xfs_ioend *ioend = iocb->private;
1315 * blockdev_direct_IO can return an error even after the I/O
1316 * completion handler was called. Thus we need to protect
1317 * against double-freeing.
1319 iocb->private = NULL;
1321 ioend->io_offset = offset;
1322 ioend->io_size = size;
1323 if (private && size > 0)
1324 ioend->io_type = IO_UNWRITTEN;
1326 if (is_async) {
1328 * If we are converting an unwritten extent we need to delay
1329 * the AIO completion until after the unwrittent extent
1330 * conversion has completed, otherwise do it ASAP.
1332 if (ioend->io_type == IO_UNWRITTEN) {
1333 ioend->io_iocb = iocb;
1334 ioend->io_result = ret;
1335 } else {
1336 aio_complete(iocb, ret, 0);
1338 xfs_finish_ioend(ioend);
1339 } else {
1340 xfs_finish_ioend_sync(ioend);
1344 STATIC ssize_t
1345 xfs_vm_direct_IO(
1346 int rw,
1347 struct kiocb *iocb,
1348 const struct iovec *iov,
1349 loff_t offset,
1350 unsigned long nr_segs)
1352 struct inode *inode = iocb->ki_filp->f_mapping->host;
1353 struct block_device *bdev = xfs_find_bdev_for_inode(inode);
1354 ssize_t ret;
1356 if (rw & WRITE) {
1357 iocb->private = xfs_alloc_ioend(inode, IO_DIRECT);
1359 ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
1360 offset, nr_segs,
1361 xfs_get_blocks_direct,
1362 xfs_end_io_direct_write, NULL, 0);
1363 if (ret != -EIOCBQUEUED && iocb->private)
1364 xfs_destroy_ioend(iocb->private);
1365 } else {
1366 ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
1367 offset, nr_segs,
1368 xfs_get_blocks_direct,
1369 NULL, NULL, 0);
1372 return ret;
1375 STATIC void
1376 xfs_vm_write_failed(
1377 struct address_space *mapping,
1378 loff_t to)
1380 struct inode *inode = mapping->host;
1382 if (to > inode->i_size) {
1384 * punch out the delalloc blocks we have already allocated. We
1385 * don't call xfs_setattr() to do this as we may be in the
1386 * middle of a multi-iovec write and so the vfs inode->i_size
1387 * will not match the xfs ip->i_size and so it will zero too
1388 * much. Hence we jus truncate the page cache to zero what is
1389 * necessary and punch the delalloc blocks directly.
1391 struct xfs_inode *ip = XFS_I(inode);
1392 xfs_fileoff_t start_fsb;
1393 xfs_fileoff_t end_fsb;
1394 int error;
1396 truncate_pagecache(inode, to, inode->i_size);
1399 * Check if there are any blocks that are outside of i_size
1400 * that need to be trimmed back.
1402 start_fsb = XFS_B_TO_FSB(ip->i_mount, inode->i_size) + 1;
1403 end_fsb = XFS_B_TO_FSB(ip->i_mount, to);
1404 if (end_fsb <= start_fsb)
1405 return;
1407 xfs_ilock(ip, XFS_ILOCK_EXCL);
1408 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
1409 end_fsb - start_fsb);
1410 if (error) {
1411 /* something screwed, just bail */
1412 if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
1413 xfs_alert(ip->i_mount,
1414 "xfs_vm_write_failed: unable to clean up ino %lld",
1415 ip->i_ino);
1418 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1422 STATIC int
1423 xfs_vm_write_begin(
1424 struct file *file,
1425 struct address_space *mapping,
1426 loff_t pos,
1427 unsigned len,
1428 unsigned flags,
1429 struct page **pagep,
1430 void **fsdata)
1432 int ret;
1434 ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
1435 pagep, xfs_get_blocks);
1436 if (unlikely(ret))
1437 xfs_vm_write_failed(mapping, pos + len);
1438 return ret;
1441 STATIC int
1442 xfs_vm_write_end(
1443 struct file *file,
1444 struct address_space *mapping,
1445 loff_t pos,
1446 unsigned len,
1447 unsigned copied,
1448 struct page *page,
1449 void *fsdata)
1451 int ret;
1453 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
1454 if (unlikely(ret < len))
1455 xfs_vm_write_failed(mapping, pos + len);
1456 return ret;
1459 STATIC sector_t
1460 xfs_vm_bmap(
1461 struct address_space *mapping,
1462 sector_t block)
1464 struct inode *inode = (struct inode *)mapping->host;
1465 struct xfs_inode *ip = XFS_I(inode);
1467 trace_xfs_vm_bmap(XFS_I(inode));
1468 xfs_ilock(ip, XFS_IOLOCK_SHARED);
1469 xfs_flush_pages(ip, (xfs_off_t)0, -1, 0, FI_REMAPF);
1470 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
1471 return generic_block_bmap(mapping, block, xfs_get_blocks);
1474 STATIC int
1475 xfs_vm_readpage(
1476 struct file *unused,
1477 struct page *page)
1479 return mpage_readpage(page, xfs_get_blocks);
1482 STATIC int
1483 xfs_vm_readpages(
1484 struct file *unused,
1485 struct address_space *mapping,
1486 struct list_head *pages,
1487 unsigned nr_pages)
1489 return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
1492 const struct address_space_operations xfs_address_space_operations = {
1493 .readpage = xfs_vm_readpage,
1494 .readpages = xfs_vm_readpages,
1495 .writepage = xfs_vm_writepage,
1496 .writepages = xfs_vm_writepages,
1497 .releasepage = xfs_vm_releasepage,
1498 .invalidatepage = xfs_vm_invalidatepage,
1499 .write_begin = xfs_vm_write_begin,
1500 .write_end = xfs_vm_write_end,
1501 .bmap = xfs_vm_bmap,
1502 .direct_IO = xfs_vm_direct_IO,
1503 .migratepage = buffer_migrate_page,
1504 .is_partially_uptodate = block_is_partially_uptodate,
1505 .error_remove_page = generic_error_remove_page,