Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * Copyright (c) 2016-2018 Christoph Hellwig.
5 * All Rights Reserved.
6 */
7#include "xfs.h"
8#include "xfs_shared.h"
9#include "xfs_format.h"
10#include "xfs_log_format.h"
11#include "xfs_trans_resv.h"
12#include "xfs_mount.h"
13#include "xfs_inode.h"
14#include "xfs_trans.h"
15#include "xfs_iomap.h"
16#include "xfs_trace.h"
17#include "xfs_bmap.h"
18#include "xfs_bmap_util.h"
19#include "xfs_reflink.h"
20
21struct xfs_writepage_ctx {
22 struct iomap_writepage_ctx ctx;
23 unsigned int data_seq;
24 unsigned int cow_seq;
25};
26
27static inline struct xfs_writepage_ctx *
28XFS_WPC(struct iomap_writepage_ctx *ctx)
29{
30 return container_of(ctx, struct xfs_writepage_ctx, ctx);
31}
32
33/*
34 * Fast and loose check if this write could update the on-disk inode size.
35 */
36static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
37{
38 return ioend->io_offset + ioend->io_size >
39 XFS_I(ioend->io_inode)->i_disk_size;
40}
41
42/*
43 * Update on-disk file size now that data has been written to disk.
44 */
45int
46xfs_setfilesize(
47 struct xfs_inode *ip,
48 xfs_off_t offset,
49 size_t size)
50{
51 struct xfs_mount *mp = ip->i_mount;
52 struct xfs_trans *tp;
53 xfs_fsize_t isize;
54 int error;
55
56 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
57 if (error)
58 return error;
59
60 xfs_ilock(ip, XFS_ILOCK_EXCL);
61 isize = xfs_new_eof(ip, offset + size);
62 if (!isize) {
63 xfs_iunlock(ip, XFS_ILOCK_EXCL);
64 xfs_trans_cancel(tp);
65 return 0;
66 }
67
68 trace_xfs_setfilesize(ip, offset, size);
69
70 ip->i_disk_size = isize;
71 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
72 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
73
74 return xfs_trans_commit(tp);
75}
76
77/*
78 * IO write completion.
79 */
80STATIC void
81xfs_end_ioend(
82 struct iomap_ioend *ioend)
83{
84 struct xfs_inode *ip = XFS_I(ioend->io_inode);
85 xfs_off_t offset = ioend->io_offset;
86 size_t size = ioend->io_size;
87 unsigned int nofs_flag;
88 int error;
89
90 /*
91 * We can allocate memory here while doing writeback on behalf of
92 * memory reclaim. To avoid memory allocation deadlocks set the
93 * task-wide nofs context for the following operations.
94 */
95 nofs_flag = memalloc_nofs_save();
96
97 /*
98 * Just clean up the in-memory structures if the fs has been shut down.
99 */
100 if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
101 error = -EIO;
102 goto done;
103 }
104
105 /*
106 * Clean up any COW blocks on an I/O error.
107 */
108 error = blk_status_to_errno(ioend->io_bio->bi_status);
109 if (unlikely(error)) {
110 if (ioend->io_flags & IOMAP_F_SHARED)
111 xfs_reflink_cancel_cow_range(ip, offset, size, true);
112 goto done;
113 }
114
115 /*
116 * Success: commit the COW or unwritten blocks if needed.
117 */
118 if (ioend->io_flags & IOMAP_F_SHARED)
119 error = xfs_reflink_end_cow(ip, offset, size);
120 else if (ioend->io_type == IOMAP_UNWRITTEN)
121 error = xfs_iomap_write_unwritten(ip, offset, size, false);
122
123 if (!error && xfs_ioend_is_append(ioend))
124 error = xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
125done:
126 iomap_finish_ioends(ioend, error);
127 memalloc_nofs_restore(nofs_flag);
128}
129
130/* Finish all pending io completions. */
131void
132xfs_end_io(
133 struct work_struct *work)
134{
135 struct xfs_inode *ip =
136 container_of(work, struct xfs_inode, i_ioend_work);
137 struct iomap_ioend *ioend;
138 struct list_head tmp;
139 unsigned long flags;
140
141 spin_lock_irqsave(&ip->i_ioend_lock, flags);
142 list_replace_init(&ip->i_ioend_list, &tmp);
143 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
144
145 iomap_sort_ioends(&tmp);
146 while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
147 io_list))) {
148 list_del_init(&ioend->io_list);
149 iomap_ioend_try_merge(ioend, &tmp);
150 xfs_end_ioend(ioend);
151 }
152}
153
154STATIC void
155xfs_end_bio(
156 struct bio *bio)
157{
158 struct iomap_ioend *ioend = bio->bi_private;
159 struct xfs_inode *ip = XFS_I(ioend->io_inode);
160 unsigned long flags;
161
162 spin_lock_irqsave(&ip->i_ioend_lock, flags);
163 if (list_empty(&ip->i_ioend_list))
164 WARN_ON_ONCE(!queue_work(ip->i_mount->m_unwritten_workqueue,
165 &ip->i_ioend_work));
166 list_add_tail(&ioend->io_list, &ip->i_ioend_list);
167 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
168}
169
170/*
171 * Fast revalidation of the cached writeback mapping. Return true if the current
172 * mapping is valid, false otherwise.
173 */
174static bool
175xfs_imap_valid(
176 struct iomap_writepage_ctx *wpc,
177 struct xfs_inode *ip,
178 loff_t offset)
179{
180 if (offset < wpc->iomap.offset ||
181 offset >= wpc->iomap.offset + wpc->iomap.length)
182 return false;
183 /*
184 * If this is a COW mapping, it is sufficient to check that the mapping
185 * covers the offset. Be careful to check this first because the caller
186 * can revalidate a COW mapping without updating the data seqno.
187 */
188 if (wpc->iomap.flags & IOMAP_F_SHARED)
189 return true;
190
191 /*
192 * This is not a COW mapping. Check the sequence number of the data fork
193 * because concurrent changes could have invalidated the extent. Check
194 * the COW fork because concurrent changes since the last time we
195 * checked (and found nothing at this offset) could have added
196 * overlapping blocks.
197 */
198 if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq))
199 return false;
200 if (xfs_inode_has_cow_data(ip) &&
201 XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq))
202 return false;
203 return true;
204}
205
206/*
207 * Pass in a dellalloc extent and convert it to real extents, return the real
208 * extent that maps offset_fsb in wpc->iomap.
209 *
210 * The current page is held locked so nothing could have removed the block
211 * backing offset_fsb, although it could have moved from the COW to the data
212 * fork by another thread.
213 */
214static int
215xfs_convert_blocks(
216 struct iomap_writepage_ctx *wpc,
217 struct xfs_inode *ip,
218 int whichfork,
219 loff_t offset)
220{
221 int error;
222 unsigned *seq;
223
224 if (whichfork == XFS_COW_FORK)
225 seq = &XFS_WPC(wpc)->cow_seq;
226 else
227 seq = &XFS_WPC(wpc)->data_seq;
228
229 /*
230 * Attempt to allocate whatever delalloc extent currently backs offset
231 * and put the result into wpc->iomap. Allocate in a loop because it
232 * may take several attempts to allocate real blocks for a contiguous
233 * delalloc extent if free space is sufficiently fragmented.
234 */
235 do {
236 error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
237 &wpc->iomap, seq);
238 if (error)
239 return error;
240 } while (wpc->iomap.offset + wpc->iomap.length <= offset);
241
242 return 0;
243}
244
245static int
246xfs_map_blocks(
247 struct iomap_writepage_ctx *wpc,
248 struct inode *inode,
249 loff_t offset)
250{
251 struct xfs_inode *ip = XFS_I(inode);
252 struct xfs_mount *mp = ip->i_mount;
253 ssize_t count = i_blocksize(inode);
254 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
255 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
256 xfs_fileoff_t cow_fsb;
257 int whichfork;
258 struct xfs_bmbt_irec imap;
259 struct xfs_iext_cursor icur;
260 int retries = 0;
261 int error = 0;
262
263 if (XFS_FORCED_SHUTDOWN(mp))
264 return -EIO;
265
266 /*
267 * COW fork blocks can overlap data fork blocks even if the blocks
268 * aren't shared. COW I/O always takes precedent, so we must always
269 * check for overlap on reflink inodes unless the mapping is already a
270 * COW one, or the COW fork hasn't changed from the last time we looked
271 * at it.
272 *
273 * It's safe to check the COW fork if_seq here without the ILOCK because
274 * we've indirectly protected against concurrent updates: writeback has
275 * the page locked, which prevents concurrent invalidations by reflink
276 * and directio and prevents concurrent buffered writes to the same
277 * page. Changes to if_seq always happen under i_lock, which protects
278 * against concurrent updates and provides a memory barrier on the way
279 * out that ensures that we always see the current value.
280 */
281 if (xfs_imap_valid(wpc, ip, offset))
282 return 0;
283
284 /*
285 * If we don't have a valid map, now it's time to get a new one for this
286 * offset. This will convert delayed allocations (including COW ones)
287 * into real extents. If we return without a valid map, it means we
288 * landed in a hole and we skip the block.
289 */
290retry:
291 cow_fsb = NULLFILEOFF;
292 whichfork = XFS_DATA_FORK;
293 xfs_ilock(ip, XFS_ILOCK_SHARED);
294 ASSERT(!xfs_need_iread_extents(&ip->i_df));
295
296 /*
297 * Check if this is offset is covered by a COW extents, and if yes use
298 * it directly instead of looking up anything in the data fork.
299 */
300 if (xfs_inode_has_cow_data(ip) &&
301 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
302 cow_fsb = imap.br_startoff;
303 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
304 XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
305 xfs_iunlock(ip, XFS_ILOCK_SHARED);
306
307 whichfork = XFS_COW_FORK;
308 goto allocate_blocks;
309 }
310
311 /*
312 * No COW extent overlap. Revalidate now that we may have updated
313 * ->cow_seq. If the data mapping is still valid, we're done.
314 */
315 if (xfs_imap_valid(wpc, ip, offset)) {
316 xfs_iunlock(ip, XFS_ILOCK_SHARED);
317 return 0;
318 }
319
320 /*
321 * If we don't have a valid map, now it's time to get a new one for this
322 * offset. This will convert delayed allocations (including COW ones)
323 * into real extents.
324 */
325 if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
326 imap.br_startoff = end_fsb; /* fake a hole past EOF */
327 XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
328 xfs_iunlock(ip, XFS_ILOCK_SHARED);
329
330 /* landed in a hole or beyond EOF? */
331 if (imap.br_startoff > offset_fsb) {
332 imap.br_blockcount = imap.br_startoff - offset_fsb;
333 imap.br_startoff = offset_fsb;
334 imap.br_startblock = HOLESTARTBLOCK;
335 imap.br_state = XFS_EXT_NORM;
336 }
337
338 /*
339 * Truncate to the next COW extent if there is one. This is the only
340 * opportunity to do this because we can skip COW fork lookups for the
341 * subsequent blocks in the mapping; however, the requirement to treat
342 * the COW range separately remains.
343 */
344 if (cow_fsb != NULLFILEOFF &&
345 cow_fsb < imap.br_startoff + imap.br_blockcount)
346 imap.br_blockcount = cow_fsb - imap.br_startoff;
347
348 /* got a delalloc extent? */
349 if (imap.br_startblock != HOLESTARTBLOCK &&
350 isnullstartblock(imap.br_startblock))
351 goto allocate_blocks;
352
353 xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0);
354 trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
355 return 0;
356allocate_blocks:
357 error = xfs_convert_blocks(wpc, ip, whichfork, offset);
358 if (error) {
359 /*
360 * If we failed to find the extent in the COW fork we might have
361 * raced with a COW to data fork conversion or truncate.
362 * Restart the lookup to catch the extent in the data fork for
363 * the former case, but prevent additional retries to avoid
364 * looping forever for the latter case.
365 */
366 if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
367 goto retry;
368 ASSERT(error != -EAGAIN);
369 return error;
370 }
371
372 /*
373 * Due to merging the return real extent might be larger than the
374 * original delalloc one. Trim the return extent to the next COW
375 * boundary again to force a re-lookup.
376 */
377 if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
378 loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);
379
380 if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
381 wpc->iomap.length = cow_offset - wpc->iomap.offset;
382 }
383
384 ASSERT(wpc->iomap.offset <= offset);
385 ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
386 trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
387 return 0;
388}
389
390static int
391xfs_prepare_ioend(
392 struct iomap_ioend *ioend,
393 int status)
394{
395 unsigned int nofs_flag;
396
397 /*
398 * We can allocate memory here while doing writeback on behalf of
399 * memory reclaim. To avoid memory allocation deadlocks set the
400 * task-wide nofs context for the following operations.
401 */
402 nofs_flag = memalloc_nofs_save();
403
404 /* Convert CoW extents to regular */
405 if (!status && (ioend->io_flags & IOMAP_F_SHARED)) {
406 status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
407 ioend->io_offset, ioend->io_size);
408 }
409
410 memalloc_nofs_restore(nofs_flag);
411
412 /* send ioends that might require a transaction to the completion wq */
413 if (xfs_ioend_is_append(ioend) || ioend->io_type == IOMAP_UNWRITTEN ||
414 (ioend->io_flags & IOMAP_F_SHARED))
415 ioend->io_bio->bi_end_io = xfs_end_bio;
416 return status;
417}
418
419/*
420 * If the page has delalloc blocks on it, we need to punch them out before we
421 * invalidate the page. If we don't, we leave a stale delalloc mapping on the
422 * inode that can trip up a later direct I/O read operation on the same region.
423 *
424 * We prevent this by truncating away the delalloc regions on the page. Because
425 * they are delalloc, we can do this without needing a transaction. Indeed - if
426 * we get ENOSPC errors, we have to be able to do this truncation without a
427 * transaction as there is no space left for block reservation (typically why we
428 * see a ENOSPC in writeback).
429 */
430static void
431xfs_discard_page(
432 struct page *page,
433 loff_t fileoff)
434{
435 struct inode *inode = page->mapping->host;
436 struct xfs_inode *ip = XFS_I(inode);
437 struct xfs_mount *mp = ip->i_mount;
438 unsigned int pageoff = offset_in_page(fileoff);
439 xfs_fileoff_t start_fsb = XFS_B_TO_FSBT(mp, fileoff);
440 xfs_fileoff_t pageoff_fsb = XFS_B_TO_FSBT(mp, pageoff);
441 int error;
442
443 if (XFS_FORCED_SHUTDOWN(mp))
444 goto out_invalidate;
445
446 xfs_alert_ratelimited(mp,
447 "page discard on page "PTR_FMT", inode 0x%llx, offset %llu.",
448 page, ip->i_ino, fileoff);
449
450 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
451 i_blocks_per_page(inode, page) - pageoff_fsb);
452 if (error && !XFS_FORCED_SHUTDOWN(mp))
453 xfs_alert(mp, "page discard unable to remove delalloc mapping.");
454out_invalidate:
455 iomap_invalidatepage(page, pageoff, PAGE_SIZE - pageoff);
456}
457
458static const struct iomap_writeback_ops xfs_writeback_ops = {
459 .map_blocks = xfs_map_blocks,
460 .prepare_ioend = xfs_prepare_ioend,
461 .discard_page = xfs_discard_page,
462};
463
464STATIC int
465xfs_vm_writepage(
466 struct page *page,
467 struct writeback_control *wbc)
468{
469 struct xfs_writepage_ctx wpc = { };
470
471 if (WARN_ON_ONCE(current->journal_info)) {
472 redirty_page_for_writepage(wbc, page);
473 unlock_page(page);
474 return 0;
475 }
476
477 return iomap_writepage(page, wbc, &wpc.ctx, &xfs_writeback_ops);
478}
479
480STATIC int
481xfs_vm_writepages(
482 struct address_space *mapping,
483 struct writeback_control *wbc)
484{
485 struct xfs_writepage_ctx wpc = { };
486
487 /*
488 * Writing back data in a transaction context can result in recursive
489 * transactions. This is bad, so issue a warning and get out of here.
490 */
491 if (WARN_ON_ONCE(current->journal_info))
492 return 0;
493
494 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
495 return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops);
496}
497
498STATIC int
499xfs_dax_writepages(
500 struct address_space *mapping,
501 struct writeback_control *wbc)
502{
503 struct xfs_inode *ip = XFS_I(mapping->host);
504
505 xfs_iflags_clear(ip, XFS_ITRUNCATED);
506 return dax_writeback_mapping_range(mapping,
507 xfs_inode_buftarg(ip)->bt_daxdev, wbc);
508}
509
510STATIC sector_t
511xfs_vm_bmap(
512 struct address_space *mapping,
513 sector_t block)
514{
515 struct xfs_inode *ip = XFS_I(mapping->host);
516
517 trace_xfs_vm_bmap(ip);
518
519 /*
520 * The swap code (ab-)uses ->bmap to get a block mapping and then
521 * bypasses the file system for actual I/O. We really can't allow
522 * that on reflinks inodes, so we have to skip out here. And yes,
523 * 0 is the magic code for a bmap error.
524 *
525 * Since we don't pass back blockdev info, we can't return bmap
526 * information for rt files either.
527 */
528 if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
529 return 0;
530 return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
531}
532
533STATIC int
534xfs_vm_readpage(
535 struct file *unused,
536 struct page *page)
537{
538 return iomap_readpage(page, &xfs_read_iomap_ops);
539}
540
541STATIC void
542xfs_vm_readahead(
543 struct readahead_control *rac)
544{
545 iomap_readahead(rac, &xfs_read_iomap_ops);
546}
547
548static int
549xfs_iomap_swapfile_activate(
550 struct swap_info_struct *sis,
551 struct file *swap_file,
552 sector_t *span)
553{
554 sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
555 return iomap_swapfile_activate(sis, swap_file, span,
556 &xfs_read_iomap_ops);
557}
558
559const struct address_space_operations xfs_address_space_operations = {
560 .readpage = xfs_vm_readpage,
561 .readahead = xfs_vm_readahead,
562 .writepage = xfs_vm_writepage,
563 .writepages = xfs_vm_writepages,
564 .set_page_dirty = __set_page_dirty_nobuffers,
565 .releasepage = iomap_releasepage,
566 .invalidatepage = iomap_invalidatepage,
567 .bmap = xfs_vm_bmap,
568 .direct_IO = noop_direct_IO,
569 .migratepage = iomap_migrate_page,
570 .is_partially_uptodate = iomap_is_partially_uptodate,
571 .error_remove_page = generic_error_remove_page,
572 .swap_activate = xfs_iomap_swapfile_activate,
573};
574
575const struct address_space_operations xfs_dax_aops = {
576 .writepages = xfs_dax_writepages,
577 .direct_IO = noop_direct_IO,
578 .set_page_dirty = __set_page_dirty_no_writeback,
579 .invalidatepage = noop_invalidatepage,
580 .swap_activate = xfs_iomap_swapfile_activate,
581};
1/*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
4 *
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.
8 *
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.
13 *
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
17 */
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>
40
41
42/*
43 * Prime number of hash buckets since address is used as the key.
44 */
45#define NVSYNC 37
46#define to_ioend_wq(v) (&xfs_ioend_wq[((unsigned long)v) % NVSYNC])
47static wait_queue_head_t xfs_ioend_wq[NVSYNC];
48
49void __init
50xfs_ioend_init(void)
51{
52 int i;
53
54 for (i = 0; i < NVSYNC; i++)
55 init_waitqueue_head(&xfs_ioend_wq[i]);
56}
57
58void
59xfs_ioend_wait(
60 xfs_inode_t *ip)
61{
62 wait_queue_head_t *wq = to_ioend_wq(ip);
63
64 wait_event(*wq, (atomic_read(&ip->i_iocount) == 0));
65}
66
67STATIC void
68xfs_ioend_wake(
69 xfs_inode_t *ip)
70{
71 if (atomic_dec_and_test(&ip->i_iocount))
72 wake_up(to_ioend_wq(ip));
73}
74
75void
76xfs_count_page_state(
77 struct page *page,
78 int *delalloc,
79 int *unwritten)
80{
81 struct buffer_head *bh, *head;
82
83 *delalloc = *unwritten = 0;
84
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);
92}
93
94STATIC struct block_device *
95xfs_find_bdev_for_inode(
96 struct inode *inode)
97{
98 struct xfs_inode *ip = XFS_I(inode);
99 struct xfs_mount *mp = ip->i_mount;
100
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;
105}
106
107/*
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.
112 */
113STATIC void
114xfs_destroy_ioend(
115 xfs_ioend_t *ioend)
116{
117 struct buffer_head *bh, *next;
118 struct xfs_inode *ip = XFS_I(ioend->io_inode);
119
120 for (bh = ioend->io_buffer_head; bh; bh = next) {
121 next = bh->b_private;
122 bh->b_end_io(bh, !ioend->io_error);
123 }
124
125 /*
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.
130 */
131 if (unlikely(ioend->io_error == -ENODEV)) {
132 xfs_do_force_shutdown(ip->i_mount, SHUTDOWN_DEVICE_REQ,
133 __FILE__, __LINE__);
134 }
135
136 xfs_ioend_wake(ip);
137 mempool_free(ioend, xfs_ioend_pool);
138}
139
140/*
141 * If the end of the current ioend is beyond the current EOF,
142 * return the new EOF value, otherwise zero.
143 */
144STATIC xfs_fsize_t
145xfs_ioend_new_eof(
146 xfs_ioend_t *ioend)
147{
148 xfs_inode_t *ip = XFS_I(ioend->io_inode);
149 xfs_fsize_t isize;
150 xfs_fsize_t bsize;
151
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;
156}
157
158/*
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.
164 *
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.
168 */
169STATIC int
170xfs_setfilesize(
171 xfs_ioend_t *ioend)
172{
173 xfs_inode_t *ip = XFS_I(ioend->io_inode);
174 xfs_fsize_t isize;
175
176 if (unlikely(ioend->io_error))
177 return 0;
178
179 if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
180 return EAGAIN;
181
182 isize = xfs_ioend_new_eof(ioend);
183 if (isize) {
184 trace_xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
185 ip->i_d.di_size = isize;
186 xfs_mark_inode_dirty(ip);
187 }
188
189 xfs_iunlock(ip, XFS_ILOCK_EXCL);
190 return 0;
191}
192
193/*
194 * Schedule IO completion handling on the final put of an ioend.
195 */
196STATIC void
197xfs_finish_ioend(
198 struct xfs_ioend *ioend)
199{
200 if (atomic_dec_and_test(&ioend->io_remaining)) {
201 if (ioend->io_type == IO_UNWRITTEN)
202 queue_work(xfsconvertd_workqueue, &ioend->io_work);
203 else
204 queue_work(xfsdatad_workqueue, &ioend->io_work);
205 }
206}
207
208/*
209 * IO write completion.
210 */
211STATIC void
212xfs_end_io(
213 struct work_struct *work)
214{
215 xfs_ioend_t *ioend = container_of(work, xfs_ioend_t, io_work);
216 struct xfs_inode *ip = XFS_I(ioend->io_inode);
217 int error = 0;
218
219 /*
220 * For unwritten extents we need to issue transactions to convert a
221 * range to normal written extens after the data I/O has finished.
222 */
223 if (ioend->io_type == IO_UNWRITTEN &&
224 likely(!ioend->io_error && !XFS_FORCED_SHUTDOWN(ip->i_mount))) {
225
226 error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
227 ioend->io_size);
228 if (error)
229 ioend->io_error = error;
230 }
231
232 /*
233 * We might have to update the on-disk file size after extending
234 * writes.
235 */
236 error = xfs_setfilesize(ioend);
237 ASSERT(!error || error == EAGAIN);
238
239 /*
240 * If we didn't complete processing of the ioend, requeue it to the
241 * tail of the workqueue for another attempt later. Otherwise destroy
242 * it.
243 */
244 if (error == EAGAIN) {
245 atomic_inc(&ioend->io_remaining);
246 xfs_finish_ioend(ioend);
247 /* ensure we don't spin on blocked ioends */
248 delay(1);
249 } else {
250 if (ioend->io_iocb)
251 aio_complete(ioend->io_iocb, ioend->io_result, 0);
252 xfs_destroy_ioend(ioend);
253 }
254}
255
256/*
257 * Call IO completion handling in caller context on the final put of an ioend.
258 */
259STATIC void
260xfs_finish_ioend_sync(
261 struct xfs_ioend *ioend)
262{
263 if (atomic_dec_and_test(&ioend->io_remaining))
264 xfs_end_io(&ioend->io_work);
265}
266
267/*
268 * Allocate and initialise an IO completion structure.
269 * We need to track unwritten extent write completion here initially.
270 * We'll need to extend this for updating the ondisk inode size later
271 * (vs. incore size).
272 */
273STATIC xfs_ioend_t *
274xfs_alloc_ioend(
275 struct inode *inode,
276 unsigned int type)
277{
278 xfs_ioend_t *ioend;
279
280 ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
281
282 /*
283 * Set the count to 1 initially, which will prevent an I/O
284 * completion callback from happening before we have started
285 * all the I/O from calling the completion routine too early.
286 */
287 atomic_set(&ioend->io_remaining, 1);
288 ioend->io_error = 0;
289 ioend->io_list = NULL;
290 ioend->io_type = type;
291 ioend->io_inode = inode;
292 ioend->io_buffer_head = NULL;
293 ioend->io_buffer_tail = NULL;
294 atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);
295 ioend->io_offset = 0;
296 ioend->io_size = 0;
297 ioend->io_iocb = NULL;
298 ioend->io_result = 0;
299
300 INIT_WORK(&ioend->io_work, xfs_end_io);
301 return ioend;
302}
303
304STATIC int
305xfs_map_blocks(
306 struct inode *inode,
307 loff_t offset,
308 struct xfs_bmbt_irec *imap,
309 int type,
310 int nonblocking)
311{
312 struct xfs_inode *ip = XFS_I(inode);
313 struct xfs_mount *mp = ip->i_mount;
314 ssize_t count = 1 << inode->i_blkbits;
315 xfs_fileoff_t offset_fsb, end_fsb;
316 int error = 0;
317 int bmapi_flags = XFS_BMAPI_ENTIRE;
318 int nimaps = 1;
319
320 if (XFS_FORCED_SHUTDOWN(mp))
321 return -XFS_ERROR(EIO);
322
323 if (type == IO_UNWRITTEN)
324 bmapi_flags |= XFS_BMAPI_IGSTATE;
325
326 if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {
327 if (nonblocking)
328 return -XFS_ERROR(EAGAIN);
329 xfs_ilock(ip, XFS_ILOCK_SHARED);
330 }
331
332 ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
333 (ip->i_df.if_flags & XFS_IFEXTENTS));
334 ASSERT(offset <= mp->m_maxioffset);
335
336 if (offset + count > mp->m_maxioffset)
337 count = mp->m_maxioffset - offset;
338 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
339 offset_fsb = XFS_B_TO_FSBT(mp, offset);
340 error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
341 bmapi_flags, NULL, 0, imap, &nimaps, NULL);
342 xfs_iunlock(ip, XFS_ILOCK_SHARED);
343
344 if (error)
345 return -XFS_ERROR(error);
346
347 if (type == IO_DELALLOC &&
348 (!nimaps || isnullstartblock(imap->br_startblock))) {
349 error = xfs_iomap_write_allocate(ip, offset, count, imap);
350 if (!error)
351 trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
352 return -XFS_ERROR(error);
353 }
354
355#ifdef DEBUG
356 if (type == IO_UNWRITTEN) {
357 ASSERT(nimaps);
358 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
359 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
360 }
361#endif
362 if (nimaps)
363 trace_xfs_map_blocks_found(ip, offset, count, type, imap);
364 return 0;
365}
366
367STATIC int
368xfs_imap_valid(
369 struct inode *inode,
370 struct xfs_bmbt_irec *imap,
371 xfs_off_t offset)
372{
373 offset >>= inode->i_blkbits;
374
375 return offset >= imap->br_startoff &&
376 offset < imap->br_startoff + imap->br_blockcount;
377}
378
379/*
380 * BIO completion handler for buffered IO.
381 */
382STATIC void
383xfs_end_bio(
384 struct bio *bio,
385 int error)
386{
387 xfs_ioend_t *ioend = bio->bi_private;
388
389 ASSERT(atomic_read(&bio->bi_cnt) >= 1);
390 ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
391
392 /* Toss bio and pass work off to an xfsdatad thread */
393 bio->bi_private = NULL;
394 bio->bi_end_io = NULL;
395 bio_put(bio);
396
397 xfs_finish_ioend(ioend);
398}
399
400STATIC void
401xfs_submit_ioend_bio(
402 struct writeback_control *wbc,
403 xfs_ioend_t *ioend,
404 struct bio *bio)
405{
406 atomic_inc(&ioend->io_remaining);
407 bio->bi_private = ioend;
408 bio->bi_end_io = xfs_end_bio;
409
410 /*
411 * If the I/O is beyond EOF we mark the inode dirty immediately
412 * but don't update the inode size until I/O completion.
413 */
414 if (xfs_ioend_new_eof(ioend))
415 xfs_mark_inode_dirty(XFS_I(ioend->io_inode));
416
417 submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio);
418}
419
420STATIC struct bio *
421xfs_alloc_ioend_bio(
422 struct buffer_head *bh)
423{
424 int nvecs = bio_get_nr_vecs(bh->b_bdev);
425 struct bio *bio = bio_alloc(GFP_NOIO, nvecs);
426
427 ASSERT(bio->bi_private == NULL);
428 bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
429 bio->bi_bdev = bh->b_bdev;
430 return bio;
431}
432
433STATIC void
434xfs_start_buffer_writeback(
435 struct buffer_head *bh)
436{
437 ASSERT(buffer_mapped(bh));
438 ASSERT(buffer_locked(bh));
439 ASSERT(!buffer_delay(bh));
440 ASSERT(!buffer_unwritten(bh));
441
442 mark_buffer_async_write(bh);
443 set_buffer_uptodate(bh);
444 clear_buffer_dirty(bh);
445}
446
447STATIC void
448xfs_start_page_writeback(
449 struct page *page,
450 int clear_dirty,
451 int buffers)
452{
453 ASSERT(PageLocked(page));
454 ASSERT(!PageWriteback(page));
455 if (clear_dirty)
456 clear_page_dirty_for_io(page);
457 set_page_writeback(page);
458 unlock_page(page);
459 /* If no buffers on the page are to be written, finish it here */
460 if (!buffers)
461 end_page_writeback(page);
462}
463
464static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
465{
466 return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
467}
468
469/*
470 * Submit all of the bios for all of the ioends we have saved up, covering the
471 * initial writepage page and also any probed pages.
472 *
473 * Because we may have multiple ioends spanning a page, we need to start
474 * writeback on all the buffers before we submit them for I/O. If we mark the
475 * buffers as we got, then we can end up with a page that only has buffers
476 * marked async write and I/O complete on can occur before we mark the other
477 * buffers async write.
478 *
479 * The end result of this is that we trip a bug in end_page_writeback() because
480 * we call it twice for the one page as the code in end_buffer_async_write()
481 * assumes that all buffers on the page are started at the same time.
482 *
483 * The fix is two passes across the ioend list - one to start writeback on the
484 * buffer_heads, and then submit them for I/O on the second pass.
485 */
486STATIC void
487xfs_submit_ioend(
488 struct writeback_control *wbc,
489 xfs_ioend_t *ioend)
490{
491 xfs_ioend_t *head = ioend;
492 xfs_ioend_t *next;
493 struct buffer_head *bh;
494 struct bio *bio;
495 sector_t lastblock = 0;
496
497 /* Pass 1 - start writeback */
498 do {
499 next = ioend->io_list;
500 for (bh = ioend->io_buffer_head; bh; bh = bh->b_private)
501 xfs_start_buffer_writeback(bh);
502 } while ((ioend = next) != NULL);
503
504 /* Pass 2 - submit I/O */
505 ioend = head;
506 do {
507 next = ioend->io_list;
508 bio = NULL;
509
510 for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
511
512 if (!bio) {
513 retry:
514 bio = xfs_alloc_ioend_bio(bh);
515 } else if (bh->b_blocknr != lastblock + 1) {
516 xfs_submit_ioend_bio(wbc, ioend, bio);
517 goto retry;
518 }
519
520 if (bio_add_buffer(bio, bh) != bh->b_size) {
521 xfs_submit_ioend_bio(wbc, ioend, bio);
522 goto retry;
523 }
524
525 lastblock = bh->b_blocknr;
526 }
527 if (bio)
528 xfs_submit_ioend_bio(wbc, ioend, bio);
529 xfs_finish_ioend(ioend);
530 } while ((ioend = next) != NULL);
531}
532
533/*
534 * Cancel submission of all buffer_heads so far in this endio.
535 * Toss the endio too. Only ever called for the initial page
536 * in a writepage request, so only ever one page.
537 */
538STATIC void
539xfs_cancel_ioend(
540 xfs_ioend_t *ioend)
541{
542 xfs_ioend_t *next;
543 struct buffer_head *bh, *next_bh;
544
545 do {
546 next = ioend->io_list;
547 bh = ioend->io_buffer_head;
548 do {
549 next_bh = bh->b_private;
550 clear_buffer_async_write(bh);
551 unlock_buffer(bh);
552 } while ((bh = next_bh) != NULL);
553
554 xfs_ioend_wake(XFS_I(ioend->io_inode));
555 mempool_free(ioend, xfs_ioend_pool);
556 } while ((ioend = next) != NULL);
557}
558
559/*
560 * Test to see if we've been building up a completion structure for
561 * earlier buffers -- if so, we try to append to this ioend if we
562 * can, otherwise we finish off any current ioend and start another.
563 * Return true if we've finished the given ioend.
564 */
565STATIC void
566xfs_add_to_ioend(
567 struct inode *inode,
568 struct buffer_head *bh,
569 xfs_off_t offset,
570 unsigned int type,
571 xfs_ioend_t **result,
572 int need_ioend)
573{
574 xfs_ioend_t *ioend = *result;
575
576 if (!ioend || need_ioend || type != ioend->io_type) {
577 xfs_ioend_t *previous = *result;
578
579 ioend = xfs_alloc_ioend(inode, type);
580 ioend->io_offset = offset;
581 ioend->io_buffer_head = bh;
582 ioend->io_buffer_tail = bh;
583 if (previous)
584 previous->io_list = ioend;
585 *result = ioend;
586 } else {
587 ioend->io_buffer_tail->b_private = bh;
588 ioend->io_buffer_tail = bh;
589 }
590
591 bh->b_private = NULL;
592 ioend->io_size += bh->b_size;
593}
594
595STATIC void
596xfs_map_buffer(
597 struct inode *inode,
598 struct buffer_head *bh,
599 struct xfs_bmbt_irec *imap,
600 xfs_off_t offset)
601{
602 sector_t bn;
603 struct xfs_mount *m = XFS_I(inode)->i_mount;
604 xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
605 xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
606
607 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
608 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
609
610 bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
611 ((offset - iomap_offset) >> inode->i_blkbits);
612
613 ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
614
615 bh->b_blocknr = bn;
616 set_buffer_mapped(bh);
617}
618
619STATIC void
620xfs_map_at_offset(
621 struct inode *inode,
622 struct buffer_head *bh,
623 struct xfs_bmbt_irec *imap,
624 xfs_off_t offset)
625{
626 ASSERT(imap->br_startblock != HOLESTARTBLOCK);
627 ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
628
629 xfs_map_buffer(inode, bh, imap, offset);
630 set_buffer_mapped(bh);
631 clear_buffer_delay(bh);
632 clear_buffer_unwritten(bh);
633}
634
635/*
636 * Test if a given page is suitable for writing as part of an unwritten
637 * or delayed allocate extent.
638 */
639STATIC int
640xfs_is_delayed_page(
641 struct page *page,
642 unsigned int type)
643{
644 if (PageWriteback(page))
645 return 0;
646
647 if (page->mapping && page_has_buffers(page)) {
648 struct buffer_head *bh, *head;
649 int acceptable = 0;
650
651 bh = head = page_buffers(page);
652 do {
653 if (buffer_unwritten(bh))
654 acceptable = (type == IO_UNWRITTEN);
655 else if (buffer_delay(bh))
656 acceptable = (type == IO_DELALLOC);
657 else if (buffer_dirty(bh) && buffer_mapped(bh))
658 acceptable = (type == IO_OVERWRITE);
659 else
660 break;
661 } while ((bh = bh->b_this_page) != head);
662
663 if (acceptable)
664 return 1;
665 }
666
667 return 0;
668}
669
670/*
671 * Allocate & map buffers for page given the extent map. Write it out.
672 * except for the original page of a writepage, this is called on
673 * delalloc/unwritten pages only, for the original page it is possible
674 * that the page has no mapping at all.
675 */
676STATIC int
677xfs_convert_page(
678 struct inode *inode,
679 struct page *page,
680 loff_t tindex,
681 struct xfs_bmbt_irec *imap,
682 xfs_ioend_t **ioendp,
683 struct writeback_control *wbc)
684{
685 struct buffer_head *bh, *head;
686 xfs_off_t end_offset;
687 unsigned long p_offset;
688 unsigned int type;
689 int len, page_dirty;
690 int count = 0, done = 0, uptodate = 1;
691 xfs_off_t offset = page_offset(page);
692
693 if (page->index != tindex)
694 goto fail;
695 if (!trylock_page(page))
696 goto fail;
697 if (PageWriteback(page))
698 goto fail_unlock_page;
699 if (page->mapping != inode->i_mapping)
700 goto fail_unlock_page;
701 if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
702 goto fail_unlock_page;
703
704 /*
705 * page_dirty is initially a count of buffers on the page before
706 * EOF and is decremented as we move each into a cleanable state.
707 *
708 * Derivation:
709 *
710 * End offset is the highest offset that this page should represent.
711 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
712 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
713 * hence give us the correct page_dirty count. On any other page,
714 * it will be zero and in that case we need page_dirty to be the
715 * count of buffers on the page.
716 */
717 end_offset = min_t(unsigned long long,
718 (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
719 i_size_read(inode));
720
721 len = 1 << inode->i_blkbits;
722 p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
723 PAGE_CACHE_SIZE);
724 p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
725 page_dirty = p_offset / len;
726
727 bh = head = page_buffers(page);
728 do {
729 if (offset >= end_offset)
730 break;
731 if (!buffer_uptodate(bh))
732 uptodate = 0;
733 if (!(PageUptodate(page) || buffer_uptodate(bh))) {
734 done = 1;
735 continue;
736 }
737
738 if (buffer_unwritten(bh) || buffer_delay(bh) ||
739 buffer_mapped(bh)) {
740 if (buffer_unwritten(bh))
741 type = IO_UNWRITTEN;
742 else if (buffer_delay(bh))
743 type = IO_DELALLOC;
744 else
745 type = IO_OVERWRITE;
746
747 if (!xfs_imap_valid(inode, imap, offset)) {
748 done = 1;
749 continue;
750 }
751
752 lock_buffer(bh);
753 if (type != IO_OVERWRITE)
754 xfs_map_at_offset(inode, bh, imap, offset);
755 xfs_add_to_ioend(inode, bh, offset, type,
756 ioendp, done);
757
758 page_dirty--;
759 count++;
760 } else {
761 done = 1;
762 }
763 } while (offset += len, (bh = bh->b_this_page) != head);
764
765 if (uptodate && bh == head)
766 SetPageUptodate(page);
767
768 if (count) {
769 if (--wbc->nr_to_write <= 0 &&
770 wbc->sync_mode == WB_SYNC_NONE)
771 done = 1;
772 }
773 xfs_start_page_writeback(page, !page_dirty, count);
774
775 return done;
776 fail_unlock_page:
777 unlock_page(page);
778 fail:
779 return 1;
780}
781
782/*
783 * Convert & write out a cluster of pages in the same extent as defined
784 * by mp and following the start page.
785 */
786STATIC void
787xfs_cluster_write(
788 struct inode *inode,
789 pgoff_t tindex,
790 struct xfs_bmbt_irec *imap,
791 xfs_ioend_t **ioendp,
792 struct writeback_control *wbc,
793 pgoff_t tlast)
794{
795 struct pagevec pvec;
796 int done = 0, i;
797
798 pagevec_init(&pvec, 0);
799 while (!done && tindex <= tlast) {
800 unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
801
802 if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
803 break;
804
805 for (i = 0; i < pagevec_count(&pvec); i++) {
806 done = xfs_convert_page(inode, pvec.pages[i], tindex++,
807 imap, ioendp, wbc);
808 if (done)
809 break;
810 }
811
812 pagevec_release(&pvec);
813 cond_resched();
814 }
815}
816
817STATIC void
818xfs_vm_invalidatepage(
819 struct page *page,
820 unsigned long offset)
821{
822 trace_xfs_invalidatepage(page->mapping->host, page, offset);
823 block_invalidatepage(page, offset);
824}
825
826/*
827 * If the page has delalloc buffers on it, we need to punch them out before we
828 * invalidate the page. If we don't, we leave a stale delalloc mapping on the
829 * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
830 * is done on that same region - the delalloc extent is returned when none is
831 * supposed to be there.
832 *
833 * We prevent this by truncating away the delalloc regions on the page before
834 * invalidating it. Because they are delalloc, we can do this without needing a
835 * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
836 * truncation without a transaction as there is no space left for block
837 * reservation (typically why we see a ENOSPC in writeback).
838 *
839 * This is not a performance critical path, so for now just do the punching a
840 * buffer head at a time.
841 */
842STATIC void
843xfs_aops_discard_page(
844 struct page *page)
845{
846 struct inode *inode = page->mapping->host;
847 struct xfs_inode *ip = XFS_I(inode);
848 struct buffer_head *bh, *head;
849 loff_t offset = page_offset(page);
850
851 if (!xfs_is_delayed_page(page, IO_DELALLOC))
852 goto out_invalidate;
853
854 if (XFS_FORCED_SHUTDOWN(ip->i_mount))
855 goto out_invalidate;
856
857 xfs_alert(ip->i_mount,
858 "page discard on page %p, inode 0x%llx, offset %llu.",
859 page, ip->i_ino, offset);
860
861 xfs_ilock(ip, XFS_ILOCK_EXCL);
862 bh = head = page_buffers(page);
863 do {
864 int error;
865 xfs_fileoff_t start_fsb;
866
867 if (!buffer_delay(bh))
868 goto next_buffer;
869
870 start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
871 error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
872 if (error) {
873 /* something screwed, just bail */
874 if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
875 xfs_alert(ip->i_mount,
876 "page discard unable to remove delalloc mapping.");
877 }
878 break;
879 }
880next_buffer:
881 offset += 1 << inode->i_blkbits;
882
883 } while ((bh = bh->b_this_page) != head);
884
885 xfs_iunlock(ip, XFS_ILOCK_EXCL);
886out_invalidate:
887 xfs_vm_invalidatepage(page, 0);
888 return;
889}
890
891/*
892 * Write out a dirty page.
893 *
894 * For delalloc space on the page we need to allocate space and flush it.
895 * For unwritten space on the page we need to start the conversion to
896 * regular allocated space.
897 * For any other dirty buffer heads on the page we should flush them.
898 */
899STATIC int
900xfs_vm_writepage(
901 struct page *page,
902 struct writeback_control *wbc)
903{
904 struct inode *inode = page->mapping->host;
905 struct buffer_head *bh, *head;
906 struct xfs_bmbt_irec imap;
907 xfs_ioend_t *ioend = NULL, *iohead = NULL;
908 loff_t offset;
909 unsigned int type;
910 __uint64_t end_offset;
911 pgoff_t end_index, last_index;
912 ssize_t len;
913 int err, imap_valid = 0, uptodate = 1;
914 int count = 0;
915 int nonblocking = 0;
916
917 trace_xfs_writepage(inode, page, 0);
918
919 ASSERT(page_has_buffers(page));
920
921 /*
922 * Refuse to write the page out if we are called from reclaim context.
923 *
924 * This avoids stack overflows when called from deeply used stacks in
925 * random callers for direct reclaim or memcg reclaim. We explicitly
926 * allow reclaim from kswapd as the stack usage there is relatively low.
927 *
928 * This should really be done by the core VM, but until that happens
929 * filesystems like XFS, btrfs and ext4 have to take care of this
930 * by themselves.
931 */
932 if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
933 goto redirty;
934
935 /*
936 * Given that we do not allow direct reclaim to call us, we should
937 * never be called while in a filesystem transaction.
938 */
939 if (WARN_ON(current->flags & PF_FSTRANS))
940 goto redirty;
941
942 /* Is this page beyond the end of the file? */
943 offset = i_size_read(inode);
944 end_index = offset >> PAGE_CACHE_SHIFT;
945 last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
946 if (page->index >= end_index) {
947 if ((page->index >= end_index + 1) ||
948 !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
949 unlock_page(page);
950 return 0;
951 }
952 }
953
954 end_offset = min_t(unsigned long long,
955 (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
956 offset);
957 len = 1 << inode->i_blkbits;
958
959 bh = head = page_buffers(page);
960 offset = page_offset(page);
961 type = IO_OVERWRITE;
962
963 if (wbc->sync_mode == WB_SYNC_NONE)
964 nonblocking = 1;
965
966 do {
967 int new_ioend = 0;
968
969 if (offset >= end_offset)
970 break;
971 if (!buffer_uptodate(bh))
972 uptodate = 0;
973
974 /*
975 * set_page_dirty dirties all buffers in a page, independent
976 * of their state. The dirty state however is entirely
977 * meaningless for holes (!mapped && uptodate), so skip
978 * buffers covering holes here.
979 */
980 if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
981 imap_valid = 0;
982 continue;
983 }
984
985 if (buffer_unwritten(bh)) {
986 if (type != IO_UNWRITTEN) {
987 type = IO_UNWRITTEN;
988 imap_valid = 0;
989 }
990 } else if (buffer_delay(bh)) {
991 if (type != IO_DELALLOC) {
992 type = IO_DELALLOC;
993 imap_valid = 0;
994 }
995 } else if (buffer_uptodate(bh)) {
996 if (type != IO_OVERWRITE) {
997 type = IO_OVERWRITE;
998 imap_valid = 0;
999 }
1000 } else {
1001 if (PageUptodate(page)) {
1002 ASSERT(buffer_mapped(bh));
1003 imap_valid = 0;
1004 }
1005 continue;
1006 }
1007
1008 if (imap_valid)
1009 imap_valid = xfs_imap_valid(inode, &imap, offset);
1010 if (!imap_valid) {
1011 /*
1012 * If we didn't have a valid mapping then we need to
1013 * put the new mapping into a separate ioend structure.
1014 * This ensures non-contiguous extents always have
1015 * separate ioends, which is particularly important
1016 * for unwritten extent conversion at I/O completion
1017 * time.
1018 */
1019 new_ioend = 1;
1020 err = xfs_map_blocks(inode, offset, &imap, type,
1021 nonblocking);
1022 if (err)
1023 goto error;
1024 imap_valid = xfs_imap_valid(inode, &imap, offset);
1025 }
1026 if (imap_valid) {
1027 lock_buffer(bh);
1028 if (type != IO_OVERWRITE)
1029 xfs_map_at_offset(inode, bh, &imap, offset);
1030 xfs_add_to_ioend(inode, bh, offset, type, &ioend,
1031 new_ioend);
1032 count++;
1033 }
1034
1035 if (!iohead)
1036 iohead = ioend;
1037
1038 } while (offset += len, ((bh = bh->b_this_page) != head));
1039
1040 if (uptodate && bh == head)
1041 SetPageUptodate(page);
1042
1043 xfs_start_page_writeback(page, 1, count);
1044
1045 if (ioend && imap_valid) {
1046 xfs_off_t end_index;
1047
1048 end_index = imap.br_startoff + imap.br_blockcount;
1049
1050 /* to bytes */
1051 end_index <<= inode->i_blkbits;
1052
1053 /* to pages */
1054 end_index = (end_index - 1) >> PAGE_CACHE_SHIFT;
1055
1056 /* check against file size */
1057 if (end_index > last_index)
1058 end_index = last_index;
1059
1060 xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
1061 wbc, end_index);
1062 }
1063
1064 if (iohead)
1065 xfs_submit_ioend(wbc, iohead);
1066
1067 return 0;
1068
1069error:
1070 if (iohead)
1071 xfs_cancel_ioend(iohead);
1072
1073 if (err == -EAGAIN)
1074 goto redirty;
1075
1076 xfs_aops_discard_page(page);
1077 ClearPageUptodate(page);
1078 unlock_page(page);
1079 return err;
1080
1081redirty:
1082 redirty_page_for_writepage(wbc, page);
1083 unlock_page(page);
1084 return 0;
1085}
1086
1087STATIC int
1088xfs_vm_writepages(
1089 struct address_space *mapping,
1090 struct writeback_control *wbc)
1091{
1092 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
1093 return generic_writepages(mapping, wbc);
1094}
1095
1096/*
1097 * Called to move a page into cleanable state - and from there
1098 * to be released. The page should already be clean. We always
1099 * have buffer heads in this call.
1100 *
1101 * Returns 1 if the page is ok to release, 0 otherwise.
1102 */
1103STATIC int
1104xfs_vm_releasepage(
1105 struct page *page,
1106 gfp_t gfp_mask)
1107{
1108 int delalloc, unwritten;
1109
1110 trace_xfs_releasepage(page->mapping->host, page, 0);
1111
1112 xfs_count_page_state(page, &delalloc, &unwritten);
1113
1114 if (WARN_ON(delalloc))
1115 return 0;
1116 if (WARN_ON(unwritten))
1117 return 0;
1118
1119 return try_to_free_buffers(page);
1120}
1121
1122STATIC int
1123__xfs_get_blocks(
1124 struct inode *inode,
1125 sector_t iblock,
1126 struct buffer_head *bh_result,
1127 int create,
1128 int direct)
1129{
1130 struct xfs_inode *ip = XFS_I(inode);
1131 struct xfs_mount *mp = ip->i_mount;
1132 xfs_fileoff_t offset_fsb, end_fsb;
1133 int error = 0;
1134 int lockmode = 0;
1135 struct xfs_bmbt_irec imap;
1136 int nimaps = 1;
1137 xfs_off_t offset;
1138 ssize_t size;
1139 int new = 0;
1140
1141 if (XFS_FORCED_SHUTDOWN(mp))
1142 return -XFS_ERROR(EIO);
1143
1144 offset = (xfs_off_t)iblock << inode->i_blkbits;
1145 ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
1146 size = bh_result->b_size;
1147
1148 if (!create && direct && offset >= i_size_read(inode))
1149 return 0;
1150
1151 if (create) {
1152 lockmode = XFS_ILOCK_EXCL;
1153 xfs_ilock(ip, lockmode);
1154 } else {
1155 lockmode = xfs_ilock_map_shared(ip);
1156 }
1157
1158 ASSERT(offset <= mp->m_maxioffset);
1159 if (offset + size > mp->m_maxioffset)
1160 size = mp->m_maxioffset - offset;
1161 end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
1162 offset_fsb = XFS_B_TO_FSBT(mp, offset);
1163
1164 error = xfs_bmapi(NULL, ip, offset_fsb, end_fsb - offset_fsb,
1165 XFS_BMAPI_ENTIRE, NULL, 0, &imap, &nimaps, NULL);
1166 if (error)
1167 goto out_unlock;
1168
1169 if (create &&
1170 (!nimaps ||
1171 (imap.br_startblock == HOLESTARTBLOCK ||
1172 imap.br_startblock == DELAYSTARTBLOCK))) {
1173 if (direct) {
1174 error = xfs_iomap_write_direct(ip, offset, size,
1175 &imap, nimaps);
1176 } else {
1177 error = xfs_iomap_write_delay(ip, offset, size, &imap);
1178 }
1179 if (error)
1180 goto out_unlock;
1181
1182 trace_xfs_get_blocks_alloc(ip, offset, size, 0, &imap);
1183 } else if (nimaps) {
1184 trace_xfs_get_blocks_found(ip, offset, size, 0, &imap);
1185 } else {
1186 trace_xfs_get_blocks_notfound(ip, offset, size);
1187 goto out_unlock;
1188 }
1189 xfs_iunlock(ip, lockmode);
1190
1191 if (imap.br_startblock != HOLESTARTBLOCK &&
1192 imap.br_startblock != DELAYSTARTBLOCK) {
1193 /*
1194 * For unwritten extents do not report a disk address on
1195 * the read case (treat as if we're reading into a hole).
1196 */
1197 if (create || !ISUNWRITTEN(&imap))
1198 xfs_map_buffer(inode, bh_result, &imap, offset);
1199 if (create && ISUNWRITTEN(&imap)) {
1200 if (direct)
1201 bh_result->b_private = inode;
1202 set_buffer_unwritten(bh_result);
1203 }
1204 }
1205
1206 /*
1207 * If this is a realtime file, data may be on a different device.
1208 * to that pointed to from the buffer_head b_bdev currently.
1209 */
1210 bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
1211
1212 /*
1213 * If we previously allocated a block out beyond eof and we are now
1214 * coming back to use it then we will need to flag it as new even if it
1215 * has a disk address.
1216 *
1217 * With sub-block writes into unwritten extents we also need to mark
1218 * the buffer as new so that the unwritten parts of the buffer gets
1219 * correctly zeroed.
1220 */
1221 if (create &&
1222 ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
1223 (offset >= i_size_read(inode)) ||
1224 (new || ISUNWRITTEN(&imap))))
1225 set_buffer_new(bh_result);
1226
1227 if (imap.br_startblock == DELAYSTARTBLOCK) {
1228 BUG_ON(direct);
1229 if (create) {
1230 set_buffer_uptodate(bh_result);
1231 set_buffer_mapped(bh_result);
1232 set_buffer_delay(bh_result);
1233 }
1234 }
1235
1236 /*
1237 * If this is O_DIRECT or the mpage code calling tell them how large
1238 * the mapping is, so that we can avoid repeated get_blocks calls.
1239 */
1240 if (direct || size > (1 << inode->i_blkbits)) {
1241 xfs_off_t mapping_size;
1242
1243 mapping_size = imap.br_startoff + imap.br_blockcount - iblock;
1244 mapping_size <<= inode->i_blkbits;
1245
1246 ASSERT(mapping_size > 0);
1247 if (mapping_size > size)
1248 mapping_size = size;
1249 if (mapping_size > LONG_MAX)
1250 mapping_size = LONG_MAX;
1251
1252 bh_result->b_size = mapping_size;
1253 }
1254
1255 return 0;
1256
1257out_unlock:
1258 xfs_iunlock(ip, lockmode);
1259 return -error;
1260}
1261
1262int
1263xfs_get_blocks(
1264 struct inode *inode,
1265 sector_t iblock,
1266 struct buffer_head *bh_result,
1267 int create)
1268{
1269 return __xfs_get_blocks(inode, iblock, bh_result, create, 0);
1270}
1271
1272STATIC int
1273xfs_get_blocks_direct(
1274 struct inode *inode,
1275 sector_t iblock,
1276 struct buffer_head *bh_result,
1277 int create)
1278{
1279 return __xfs_get_blocks(inode, iblock, bh_result, create, 1);
1280}
1281
1282/*
1283 * Complete a direct I/O write request.
1284 *
1285 * If the private argument is non-NULL __xfs_get_blocks signals us that we
1286 * need to issue a transaction to convert the range from unwritten to written
1287 * extents. In case this is regular synchronous I/O we just call xfs_end_io
1288 * to do this and we are done. But in case this was a successful AIO
1289 * request this handler is called from interrupt context, from which we
1290 * can't start transactions. In that case offload the I/O completion to
1291 * the workqueues we also use for buffered I/O completion.
1292 */
1293STATIC void
1294xfs_end_io_direct_write(
1295 struct kiocb *iocb,
1296 loff_t offset,
1297 ssize_t size,
1298 void *private,
1299 int ret,
1300 bool is_async)
1301{
1302 struct xfs_ioend *ioend = iocb->private;
1303 struct inode *inode = ioend->io_inode;
1304
1305 /*
1306 * blockdev_direct_IO can return an error even after the I/O
1307 * completion handler was called. Thus we need to protect
1308 * against double-freeing.
1309 */
1310 iocb->private = NULL;
1311
1312 ioend->io_offset = offset;
1313 ioend->io_size = size;
1314 if (private && size > 0)
1315 ioend->io_type = IO_UNWRITTEN;
1316
1317 if (is_async) {
1318 /*
1319 * If we are converting an unwritten extent we need to delay
1320 * the AIO completion until after the unwrittent extent
1321 * conversion has completed, otherwise do it ASAP.
1322 */
1323 if (ioend->io_type == IO_UNWRITTEN) {
1324 ioend->io_iocb = iocb;
1325 ioend->io_result = ret;
1326 } else {
1327 aio_complete(iocb, ret, 0);
1328 }
1329 xfs_finish_ioend(ioend);
1330 } else {
1331 xfs_finish_ioend_sync(ioend);
1332 }
1333
1334 /* XXX: probably should move into the real I/O completion handler */
1335 inode_dio_done(inode);
1336}
1337
1338STATIC ssize_t
1339xfs_vm_direct_IO(
1340 int rw,
1341 struct kiocb *iocb,
1342 const struct iovec *iov,
1343 loff_t offset,
1344 unsigned long nr_segs)
1345{
1346 struct inode *inode = iocb->ki_filp->f_mapping->host;
1347 struct block_device *bdev = xfs_find_bdev_for_inode(inode);
1348 ssize_t ret;
1349
1350 if (rw & WRITE) {
1351 iocb->private = xfs_alloc_ioend(inode, IO_DIRECT);
1352
1353 ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
1354 offset, nr_segs,
1355 xfs_get_blocks_direct,
1356 xfs_end_io_direct_write, NULL, 0);
1357 if (ret != -EIOCBQUEUED && iocb->private)
1358 xfs_destroy_ioend(iocb->private);
1359 } else {
1360 ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
1361 offset, nr_segs,
1362 xfs_get_blocks_direct,
1363 NULL, NULL, 0);
1364 }
1365
1366 return ret;
1367}
1368
1369STATIC void
1370xfs_vm_write_failed(
1371 struct address_space *mapping,
1372 loff_t to)
1373{
1374 struct inode *inode = mapping->host;
1375
1376 if (to > inode->i_size) {
1377 /*
1378 * punch out the delalloc blocks we have already allocated. We
1379 * don't call xfs_setattr() to do this as we may be in the
1380 * middle of a multi-iovec write and so the vfs inode->i_size
1381 * will not match the xfs ip->i_size and so it will zero too
1382 * much. Hence we jus truncate the page cache to zero what is
1383 * necessary and punch the delalloc blocks directly.
1384 */
1385 struct xfs_inode *ip = XFS_I(inode);
1386 xfs_fileoff_t start_fsb;
1387 xfs_fileoff_t end_fsb;
1388 int error;
1389
1390 truncate_pagecache(inode, to, inode->i_size);
1391
1392 /*
1393 * Check if there are any blocks that are outside of i_size
1394 * that need to be trimmed back.
1395 */
1396 start_fsb = XFS_B_TO_FSB(ip->i_mount, inode->i_size) + 1;
1397 end_fsb = XFS_B_TO_FSB(ip->i_mount, to);
1398 if (end_fsb <= start_fsb)
1399 return;
1400
1401 xfs_ilock(ip, XFS_ILOCK_EXCL);
1402 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
1403 end_fsb - start_fsb);
1404 if (error) {
1405 /* something screwed, just bail */
1406 if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
1407 xfs_alert(ip->i_mount,
1408 "xfs_vm_write_failed: unable to clean up ino %lld",
1409 ip->i_ino);
1410 }
1411 }
1412 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1413 }
1414}
1415
1416STATIC int
1417xfs_vm_write_begin(
1418 struct file *file,
1419 struct address_space *mapping,
1420 loff_t pos,
1421 unsigned len,
1422 unsigned flags,
1423 struct page **pagep,
1424 void **fsdata)
1425{
1426 int ret;
1427
1428 ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
1429 pagep, xfs_get_blocks);
1430 if (unlikely(ret))
1431 xfs_vm_write_failed(mapping, pos + len);
1432 return ret;
1433}
1434
1435STATIC int
1436xfs_vm_write_end(
1437 struct file *file,
1438 struct address_space *mapping,
1439 loff_t pos,
1440 unsigned len,
1441 unsigned copied,
1442 struct page *page,
1443 void *fsdata)
1444{
1445 int ret;
1446
1447 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
1448 if (unlikely(ret < len))
1449 xfs_vm_write_failed(mapping, pos + len);
1450 return ret;
1451}
1452
1453STATIC sector_t
1454xfs_vm_bmap(
1455 struct address_space *mapping,
1456 sector_t block)
1457{
1458 struct inode *inode = (struct inode *)mapping->host;
1459 struct xfs_inode *ip = XFS_I(inode);
1460
1461 trace_xfs_vm_bmap(XFS_I(inode));
1462 xfs_ilock(ip, XFS_IOLOCK_SHARED);
1463 xfs_flush_pages(ip, (xfs_off_t)0, -1, 0, FI_REMAPF);
1464 xfs_iunlock(ip, XFS_IOLOCK_SHARED);
1465 return generic_block_bmap(mapping, block, xfs_get_blocks);
1466}
1467
1468STATIC int
1469xfs_vm_readpage(
1470 struct file *unused,
1471 struct page *page)
1472{
1473 return mpage_readpage(page, xfs_get_blocks);
1474}
1475
1476STATIC int
1477xfs_vm_readpages(
1478 struct file *unused,
1479 struct address_space *mapping,
1480 struct list_head *pages,
1481 unsigned nr_pages)
1482{
1483 return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
1484}
1485
1486const struct address_space_operations xfs_address_space_operations = {
1487 .readpage = xfs_vm_readpage,
1488 .readpages = xfs_vm_readpages,
1489 .writepage = xfs_vm_writepage,
1490 .writepages = xfs_vm_writepages,
1491 .releasepage = xfs_vm_releasepage,
1492 .invalidatepage = xfs_vm_invalidatepage,
1493 .write_begin = xfs_vm_write_begin,
1494 .write_end = xfs_vm_write_end,
1495 .bmap = xfs_vm_bmap,
1496 .direct_IO = xfs_vm_direct_IO,
1497 .migratepage = buffer_migrate_page,
1498 .is_partially_uptodate = block_is_partially_uptodate,
1499 .error_remove_page = generic_error_remove_page,
1500};