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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#include "xfs_errortag.h"
21#include "xfs_error.h"
22
23struct xfs_writepage_ctx {
24 struct iomap_writepage_ctx ctx;
25 unsigned int data_seq;
26 unsigned int cow_seq;
27};
28
29static inline struct xfs_writepage_ctx *
30XFS_WPC(struct iomap_writepage_ctx *ctx)
31{
32 return container_of(ctx, struct xfs_writepage_ctx, ctx);
33}
34
35/*
36 * Fast and loose check if this write could update the on-disk inode size.
37 */
38static inline bool xfs_ioend_is_append(struct iomap_ioend *ioend)
39{
40 return ioend->io_offset + ioend->io_size >
41 XFS_I(ioend->io_inode)->i_disk_size;
42}
43
44/*
45 * Update on-disk file size now that data has been written to disk.
46 */
47int
48xfs_setfilesize(
49 struct xfs_inode *ip,
50 xfs_off_t offset,
51 size_t size)
52{
53 struct xfs_mount *mp = ip->i_mount;
54 struct xfs_trans *tp;
55 xfs_fsize_t isize;
56 int error;
57
58 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_fsyncts, 0, 0, 0, &tp);
59 if (error)
60 return error;
61
62 xfs_ilock(ip, XFS_ILOCK_EXCL);
63 isize = xfs_new_eof(ip, offset + size);
64 if (!isize) {
65 xfs_iunlock(ip, XFS_ILOCK_EXCL);
66 xfs_trans_cancel(tp);
67 return 0;
68 }
69
70 trace_xfs_setfilesize(ip, offset, size);
71
72 ip->i_disk_size = isize;
73 xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
74 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
75
76 return xfs_trans_commit(tp);
77}
78
79/*
80 * IO write completion.
81 */
82STATIC void
83xfs_end_ioend(
84 struct iomap_ioend *ioend)
85{
86 struct xfs_inode *ip = XFS_I(ioend->io_inode);
87 struct xfs_mount *mp = ip->i_mount;
88 xfs_off_t offset = ioend->io_offset;
89 size_t size = ioend->io_size;
90 unsigned int nofs_flag;
91 int error;
92
93 /*
94 * We can allocate memory here while doing writeback on behalf of
95 * memory reclaim. To avoid memory allocation deadlocks set the
96 * task-wide nofs context for the following operations.
97 */
98 nofs_flag = memalloc_nofs_save();
99
100 /*
101 * Just clean up the in-memory structures if the fs has been shut down.
102 */
103 if (xfs_is_shutdown(mp)) {
104 error = -EIO;
105 goto done;
106 }
107
108 /*
109 * Clean up all COW blocks and underlying data fork delalloc blocks on
110 * I/O error. The delalloc punch is required because this ioend was
111 * mapped to blocks in the COW fork and the associated pages are no
112 * longer dirty. If we don't remove delalloc blocks here, they become
113 * stale and can corrupt free space accounting on unmount.
114 */
115 error = blk_status_to_errno(ioend->io_bio.bi_status);
116 if (unlikely(error)) {
117 if (ioend->io_flags & IOMAP_F_SHARED) {
118 xfs_reflink_cancel_cow_range(ip, offset, size, true);
119 xfs_bmap_punch_delalloc_range(ip, offset,
120 offset + size);
121 }
122 goto done;
123 }
124
125 /*
126 * Success: commit the COW or unwritten blocks if needed.
127 */
128 if (ioend->io_flags & IOMAP_F_SHARED)
129 error = xfs_reflink_end_cow(ip, offset, size);
130 else if (ioend->io_type == IOMAP_UNWRITTEN)
131 error = xfs_iomap_write_unwritten(ip, offset, size, false);
132
133 if (!error && xfs_ioend_is_append(ioend))
134 error = xfs_setfilesize(ip, ioend->io_offset, ioend->io_size);
135done:
136 iomap_finish_ioends(ioend, error);
137 memalloc_nofs_restore(nofs_flag);
138}
139
140/*
141 * Finish all pending IO completions that require transactional modifications.
142 *
143 * We try to merge physical and logically contiguous ioends before completion to
144 * minimise the number of transactions we need to perform during IO completion.
145 * Both unwritten extent conversion and COW remapping need to iterate and modify
146 * one physical extent at a time, so we gain nothing by merging physically
147 * discontiguous extents here.
148 *
149 * The ioend chain length that we can be processing here is largely unbound in
150 * length and we may have to perform significant amounts of work on each ioend
151 * to complete it. Hence we have to be careful about holding the CPU for too
152 * long in this loop.
153 */
154void
155xfs_end_io(
156 struct work_struct *work)
157{
158 struct xfs_inode *ip =
159 container_of(work, struct xfs_inode, i_ioend_work);
160 struct iomap_ioend *ioend;
161 struct list_head tmp;
162 unsigned long flags;
163
164 spin_lock_irqsave(&ip->i_ioend_lock, flags);
165 list_replace_init(&ip->i_ioend_list, &tmp);
166 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
167
168 iomap_sort_ioends(&tmp);
169 while ((ioend = list_first_entry_or_null(&tmp, struct iomap_ioend,
170 io_list))) {
171 list_del_init(&ioend->io_list);
172 iomap_ioend_try_merge(ioend, &tmp);
173 xfs_end_ioend(ioend);
174 cond_resched();
175 }
176}
177
178STATIC void
179xfs_end_bio(
180 struct bio *bio)
181{
182 struct iomap_ioend *ioend = iomap_ioend_from_bio(bio);
183 struct xfs_inode *ip = XFS_I(ioend->io_inode);
184 unsigned long flags;
185
186 spin_lock_irqsave(&ip->i_ioend_lock, flags);
187 if (list_empty(&ip->i_ioend_list))
188 WARN_ON_ONCE(!queue_work(ip->i_mount->m_unwritten_workqueue,
189 &ip->i_ioend_work));
190 list_add_tail(&ioend->io_list, &ip->i_ioend_list);
191 spin_unlock_irqrestore(&ip->i_ioend_lock, flags);
192}
193
194/*
195 * Fast revalidation of the cached writeback mapping. Return true if the current
196 * mapping is valid, false otherwise.
197 */
198static bool
199xfs_imap_valid(
200 struct iomap_writepage_ctx *wpc,
201 struct xfs_inode *ip,
202 loff_t offset)
203{
204 if (offset < wpc->iomap.offset ||
205 offset >= wpc->iomap.offset + wpc->iomap.length)
206 return false;
207 /*
208 * If this is a COW mapping, it is sufficient to check that the mapping
209 * covers the offset. Be careful to check this first because the caller
210 * can revalidate a COW mapping without updating the data seqno.
211 */
212 if (wpc->iomap.flags & IOMAP_F_SHARED)
213 return true;
214
215 /*
216 * This is not a COW mapping. Check the sequence number of the data fork
217 * because concurrent changes could have invalidated the extent. Check
218 * the COW fork because concurrent changes since the last time we
219 * checked (and found nothing at this offset) could have added
220 * overlapping blocks.
221 */
222 if (XFS_WPC(wpc)->data_seq != READ_ONCE(ip->i_df.if_seq)) {
223 trace_xfs_wb_data_iomap_invalid(ip, &wpc->iomap,
224 XFS_WPC(wpc)->data_seq, XFS_DATA_FORK);
225 return false;
226 }
227 if (xfs_inode_has_cow_data(ip) &&
228 XFS_WPC(wpc)->cow_seq != READ_ONCE(ip->i_cowfp->if_seq)) {
229 trace_xfs_wb_cow_iomap_invalid(ip, &wpc->iomap,
230 XFS_WPC(wpc)->cow_seq, XFS_COW_FORK);
231 return false;
232 }
233 return true;
234}
235
236/*
237 * Pass in a dellalloc extent and convert it to real extents, return the real
238 * extent that maps offset_fsb in wpc->iomap.
239 *
240 * The current page is held locked so nothing could have removed the block
241 * backing offset_fsb, although it could have moved from the COW to the data
242 * fork by another thread.
243 */
244static int
245xfs_convert_blocks(
246 struct iomap_writepage_ctx *wpc,
247 struct xfs_inode *ip,
248 int whichfork,
249 loff_t offset)
250{
251 int error;
252 unsigned *seq;
253
254 if (whichfork == XFS_COW_FORK)
255 seq = &XFS_WPC(wpc)->cow_seq;
256 else
257 seq = &XFS_WPC(wpc)->data_seq;
258
259 /*
260 * Attempt to allocate whatever delalloc extent currently backs offset
261 * and put the result into wpc->iomap. Allocate in a loop because it
262 * may take several attempts to allocate real blocks for a contiguous
263 * delalloc extent if free space is sufficiently fragmented.
264 */
265 do {
266 error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
267 &wpc->iomap, seq);
268 if (error)
269 return error;
270 } while (wpc->iomap.offset + wpc->iomap.length <= offset);
271
272 return 0;
273}
274
275static int
276xfs_map_blocks(
277 struct iomap_writepage_ctx *wpc,
278 struct inode *inode,
279 loff_t offset,
280 unsigned int len)
281{
282 struct xfs_inode *ip = XFS_I(inode);
283 struct xfs_mount *mp = ip->i_mount;
284 ssize_t count = i_blocksize(inode);
285 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
286 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
287 xfs_fileoff_t cow_fsb;
288 int whichfork;
289 struct xfs_bmbt_irec imap;
290 struct xfs_iext_cursor icur;
291 int retries = 0;
292 int error = 0;
293
294 if (xfs_is_shutdown(mp))
295 return -EIO;
296
297 XFS_ERRORTAG_DELAY(mp, XFS_ERRTAG_WB_DELAY_MS);
298
299 /*
300 * COW fork blocks can overlap data fork blocks even if the blocks
301 * aren't shared. COW I/O always takes precedent, so we must always
302 * check for overlap on reflink inodes unless the mapping is already a
303 * COW one, or the COW fork hasn't changed from the last time we looked
304 * at it.
305 *
306 * It's safe to check the COW fork if_seq here without the ILOCK because
307 * we've indirectly protected against concurrent updates: writeback has
308 * the page locked, which prevents concurrent invalidations by reflink
309 * and directio and prevents concurrent buffered writes to the same
310 * page. Changes to if_seq always happen under i_lock, which protects
311 * against concurrent updates and provides a memory barrier on the way
312 * out that ensures that we always see the current value.
313 */
314 if (xfs_imap_valid(wpc, ip, offset))
315 return 0;
316
317 /*
318 * If we don't have a valid map, now it's time to get a new one for this
319 * offset. This will convert delayed allocations (including COW ones)
320 * into real extents. If we return without a valid map, it means we
321 * landed in a hole and we skip the block.
322 */
323retry:
324 cow_fsb = NULLFILEOFF;
325 whichfork = XFS_DATA_FORK;
326 xfs_ilock(ip, XFS_ILOCK_SHARED);
327 ASSERT(!xfs_need_iread_extents(&ip->i_df));
328
329 /*
330 * Check if this is offset is covered by a COW extents, and if yes use
331 * it directly instead of looking up anything in the data fork.
332 */
333 if (xfs_inode_has_cow_data(ip) &&
334 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &imap))
335 cow_fsb = imap.br_startoff;
336 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
337 XFS_WPC(wpc)->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
338 xfs_iunlock(ip, XFS_ILOCK_SHARED);
339
340 whichfork = XFS_COW_FORK;
341 goto allocate_blocks;
342 }
343
344 /*
345 * No COW extent overlap. Revalidate now that we may have updated
346 * ->cow_seq. If the data mapping is still valid, we're done.
347 */
348 if (xfs_imap_valid(wpc, ip, offset)) {
349 xfs_iunlock(ip, XFS_ILOCK_SHARED);
350 return 0;
351 }
352
353 /*
354 * If we don't have a valid map, now it's time to get a new one for this
355 * offset. This will convert delayed allocations (including COW ones)
356 * into real extents.
357 */
358 if (!xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap))
359 imap.br_startoff = end_fsb; /* fake a hole past EOF */
360 XFS_WPC(wpc)->data_seq = READ_ONCE(ip->i_df.if_seq);
361 xfs_iunlock(ip, XFS_ILOCK_SHARED);
362
363 /* landed in a hole or beyond EOF? */
364 if (imap.br_startoff > offset_fsb) {
365 imap.br_blockcount = imap.br_startoff - offset_fsb;
366 imap.br_startoff = offset_fsb;
367 imap.br_startblock = HOLESTARTBLOCK;
368 imap.br_state = XFS_EXT_NORM;
369 }
370
371 /*
372 * Truncate to the next COW extent if there is one. This is the only
373 * opportunity to do this because we can skip COW fork lookups for the
374 * subsequent blocks in the mapping; however, the requirement to treat
375 * the COW range separately remains.
376 */
377 if (cow_fsb != NULLFILEOFF &&
378 cow_fsb < imap.br_startoff + imap.br_blockcount)
379 imap.br_blockcount = cow_fsb - imap.br_startoff;
380
381 /* got a delalloc extent? */
382 if (imap.br_startblock != HOLESTARTBLOCK &&
383 isnullstartblock(imap.br_startblock))
384 goto allocate_blocks;
385
386 xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0, 0, XFS_WPC(wpc)->data_seq);
387 trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
388 return 0;
389allocate_blocks:
390 error = xfs_convert_blocks(wpc, ip, whichfork, offset);
391 if (error) {
392 /*
393 * If we failed to find the extent in the COW fork we might have
394 * raced with a COW to data fork conversion or truncate.
395 * Restart the lookup to catch the extent in the data fork for
396 * the former case, but prevent additional retries to avoid
397 * looping forever for the latter case.
398 */
399 if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
400 goto retry;
401 ASSERT(error != -EAGAIN);
402 return error;
403 }
404
405 /*
406 * Due to merging the return real extent might be larger than the
407 * original delalloc one. Trim the return extent to the next COW
408 * boundary again to force a re-lookup.
409 */
410 if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
411 loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);
412
413 if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
414 wpc->iomap.length = cow_offset - wpc->iomap.offset;
415 }
416
417 ASSERT(wpc->iomap.offset <= offset);
418 ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
419 trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
420 return 0;
421}
422
423static int
424xfs_prepare_ioend(
425 struct iomap_ioend *ioend,
426 int status)
427{
428 unsigned int nofs_flag;
429
430 /*
431 * We can allocate memory here while doing writeback on behalf of
432 * memory reclaim. To avoid memory allocation deadlocks set the
433 * task-wide nofs context for the following operations.
434 */
435 nofs_flag = memalloc_nofs_save();
436
437 /* Convert CoW extents to regular */
438 if (!status && (ioend->io_flags & IOMAP_F_SHARED)) {
439 status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
440 ioend->io_offset, ioend->io_size);
441 }
442
443 memalloc_nofs_restore(nofs_flag);
444
445 /* send ioends that might require a transaction to the completion wq */
446 if (xfs_ioend_is_append(ioend) || ioend->io_type == IOMAP_UNWRITTEN ||
447 (ioend->io_flags & IOMAP_F_SHARED))
448 ioend->io_bio.bi_end_io = xfs_end_bio;
449 return status;
450}
451
452/*
453 * If the folio has delalloc blocks on it, the caller is asking us to punch them
454 * out. If we don't, we can leave a stale delalloc mapping covered by a clean
455 * page that needs to be dirtied again before the delalloc mapping can be
456 * converted. This stale delalloc mapping can trip up a later direct I/O read
457 * operation on the same region.
458 *
459 * We prevent this by truncating away the delalloc regions on the folio. Because
460 * they are delalloc, we can do this without needing a transaction. Indeed - if
461 * we get ENOSPC errors, we have to be able to do this truncation without a
462 * transaction as there is no space left for block reservation (typically why
463 * we see a ENOSPC in writeback).
464 */
465static void
466xfs_discard_folio(
467 struct folio *folio,
468 loff_t pos)
469{
470 struct xfs_inode *ip = XFS_I(folio->mapping->host);
471 struct xfs_mount *mp = ip->i_mount;
472 int error;
473
474 if (xfs_is_shutdown(mp))
475 return;
476
477 xfs_alert_ratelimited(mp,
478 "page discard on page "PTR_FMT", inode 0x%llx, pos %llu.",
479 folio, ip->i_ino, pos);
480
481 /*
482 * The end of the punch range is always the offset of the first
483 * byte of the next folio. Hence the end offset is only dependent on the
484 * folio itself and not the start offset that is passed in.
485 */
486 error = xfs_bmap_punch_delalloc_range(ip, pos,
487 folio_pos(folio) + folio_size(folio));
488
489 if (error && !xfs_is_shutdown(mp))
490 xfs_alert(mp, "page discard unable to remove delalloc mapping.");
491}
492
493static const struct iomap_writeback_ops xfs_writeback_ops = {
494 .map_blocks = xfs_map_blocks,
495 .prepare_ioend = xfs_prepare_ioend,
496 .discard_folio = xfs_discard_folio,
497};
498
499STATIC int
500xfs_vm_writepages(
501 struct address_space *mapping,
502 struct writeback_control *wbc)
503{
504 struct xfs_writepage_ctx wpc = { };
505
506 xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
507 return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops);
508}
509
510STATIC int
511xfs_dax_writepages(
512 struct address_space *mapping,
513 struct writeback_control *wbc)
514{
515 struct xfs_inode *ip = XFS_I(mapping->host);
516
517 xfs_iflags_clear(ip, XFS_ITRUNCATED);
518 return dax_writeback_mapping_range(mapping,
519 xfs_inode_buftarg(ip)->bt_daxdev, wbc);
520}
521
522STATIC sector_t
523xfs_vm_bmap(
524 struct address_space *mapping,
525 sector_t block)
526{
527 struct xfs_inode *ip = XFS_I(mapping->host);
528
529 trace_xfs_vm_bmap(ip);
530
531 /*
532 * The swap code (ab-)uses ->bmap to get a block mapping and then
533 * bypasses the file system for actual I/O. We really can't allow
534 * that on reflinks inodes, so we have to skip out here. And yes,
535 * 0 is the magic code for a bmap error.
536 *
537 * Since we don't pass back blockdev info, we can't return bmap
538 * information for rt files either.
539 */
540 if (xfs_is_cow_inode(ip) || XFS_IS_REALTIME_INODE(ip))
541 return 0;
542 return iomap_bmap(mapping, block, &xfs_read_iomap_ops);
543}
544
545STATIC int
546xfs_vm_read_folio(
547 struct file *unused,
548 struct folio *folio)
549{
550 return iomap_read_folio(folio, &xfs_read_iomap_ops);
551}
552
553STATIC void
554xfs_vm_readahead(
555 struct readahead_control *rac)
556{
557 iomap_readahead(rac, &xfs_read_iomap_ops);
558}
559
560static int
561xfs_iomap_swapfile_activate(
562 struct swap_info_struct *sis,
563 struct file *swap_file,
564 sector_t *span)
565{
566 sis->bdev = xfs_inode_buftarg(XFS_I(file_inode(swap_file)))->bt_bdev;
567 return iomap_swapfile_activate(sis, swap_file, span,
568 &xfs_read_iomap_ops);
569}
570
571const struct address_space_operations xfs_address_space_operations = {
572 .read_folio = xfs_vm_read_folio,
573 .readahead = xfs_vm_readahead,
574 .writepages = xfs_vm_writepages,
575 .dirty_folio = iomap_dirty_folio,
576 .release_folio = iomap_release_folio,
577 .invalidate_folio = iomap_invalidate_folio,
578 .bmap = xfs_vm_bmap,
579 .migrate_folio = filemap_migrate_folio,
580 .is_partially_uptodate = iomap_is_partially_uptodate,
581 .error_remove_folio = generic_error_remove_folio,
582 .swap_activate = xfs_iomap_swapfile_activate,
583};
584
585const struct address_space_operations xfs_dax_aops = {
586 .writepages = xfs_dax_writepages,
587 .dirty_folio = noop_dirty_folio,
588 .swap_activate = xfs_iomap_swapfile_activate,
589};
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};