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1/*
2 * Copyright (c) 2000-2006 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_fs.h"
20#include "xfs_log.h"
21#include "xfs_trans.h"
22#include "xfs_sb.h"
23#include "xfs_ag.h"
24#include "xfs_alloc.h"
25#include "xfs_quota.h"
26#include "xfs_mount.h"
27#include "xfs_bmap_btree.h"
28#include "xfs_alloc_btree.h"
29#include "xfs_ialloc_btree.h"
30#include "xfs_dinode.h"
31#include "xfs_inode.h"
32#include "xfs_inode_item.h"
33#include "xfs_btree.h"
34#include "xfs_bmap.h"
35#include "xfs_rtalloc.h"
36#include "xfs_error.h"
37#include "xfs_itable.h"
38#include "xfs_attr.h"
39#include "xfs_buf_item.h"
40#include "xfs_trans_space.h"
41#include "xfs_utils.h"
42#include "xfs_iomap.h"
43#include "xfs_trace.h"
44
45
46#define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \
47 << mp->m_writeio_log)
48#define XFS_WRITE_IMAPS XFS_BMAP_MAX_NMAP
49
50STATIC int
51xfs_iomap_eof_align_last_fsb(
52 xfs_mount_t *mp,
53 xfs_inode_t *ip,
54 xfs_extlen_t extsize,
55 xfs_fileoff_t *last_fsb)
56{
57 xfs_fileoff_t new_last_fsb = 0;
58 xfs_extlen_t align = 0;
59 int eof, error;
60
61 if (!XFS_IS_REALTIME_INODE(ip)) {
62 /*
63 * Round up the allocation request to a stripe unit
64 * (m_dalign) boundary if the file size is >= stripe unit
65 * size, and we are allocating past the allocation eof.
66 *
67 * If mounted with the "-o swalloc" option the alignment is
68 * increased from the strip unit size to the stripe width.
69 */
70 if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC))
71 align = mp->m_swidth;
72 else if (mp->m_dalign)
73 align = mp->m_dalign;
74
75 if (align && XFS_ISIZE(ip) >= XFS_FSB_TO_B(mp, align))
76 new_last_fsb = roundup_64(*last_fsb, align);
77 }
78
79 /*
80 * Always round up the allocation request to an extent boundary
81 * (when file on a real-time subvolume or has di_extsize hint).
82 */
83 if (extsize) {
84 if (new_last_fsb)
85 align = roundup_64(new_last_fsb, extsize);
86 else
87 align = extsize;
88 new_last_fsb = roundup_64(*last_fsb, align);
89 }
90
91 if (new_last_fsb) {
92 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
93 if (error)
94 return error;
95 if (eof)
96 *last_fsb = new_last_fsb;
97 }
98 return 0;
99}
100
101STATIC int
102xfs_alert_fsblock_zero(
103 xfs_inode_t *ip,
104 xfs_bmbt_irec_t *imap)
105{
106 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
107 "Access to block zero in inode %llu "
108 "start_block: %llx start_off: %llx "
109 "blkcnt: %llx extent-state: %x\n",
110 (unsigned long long)ip->i_ino,
111 (unsigned long long)imap->br_startblock,
112 (unsigned long long)imap->br_startoff,
113 (unsigned long long)imap->br_blockcount,
114 imap->br_state);
115 return EFSCORRUPTED;
116}
117
118int
119xfs_iomap_write_direct(
120 xfs_inode_t *ip,
121 xfs_off_t offset,
122 size_t count,
123 xfs_bmbt_irec_t *imap,
124 int nmaps)
125{
126 xfs_mount_t *mp = ip->i_mount;
127 xfs_fileoff_t offset_fsb;
128 xfs_fileoff_t last_fsb;
129 xfs_filblks_t count_fsb, resaligned;
130 xfs_fsblock_t firstfsb;
131 xfs_extlen_t extsz, temp;
132 int nimaps;
133 int bmapi_flag;
134 int quota_flag;
135 int rt;
136 xfs_trans_t *tp;
137 xfs_bmap_free_t free_list;
138 uint qblocks, resblks, resrtextents;
139 int committed;
140 int error;
141
142 error = xfs_qm_dqattach(ip, 0);
143 if (error)
144 return XFS_ERROR(error);
145
146 rt = XFS_IS_REALTIME_INODE(ip);
147 extsz = xfs_get_extsz_hint(ip);
148
149 offset_fsb = XFS_B_TO_FSBT(mp, offset);
150 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
151 if ((offset + count) > XFS_ISIZE(ip)) {
152 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
153 if (error)
154 return XFS_ERROR(error);
155 } else {
156 if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
157 last_fsb = MIN(last_fsb, (xfs_fileoff_t)
158 imap->br_blockcount +
159 imap->br_startoff);
160 }
161 count_fsb = last_fsb - offset_fsb;
162 ASSERT(count_fsb > 0);
163
164 resaligned = count_fsb;
165 if (unlikely(extsz)) {
166 if ((temp = do_mod(offset_fsb, extsz)))
167 resaligned += temp;
168 if ((temp = do_mod(resaligned, extsz)))
169 resaligned += extsz - temp;
170 }
171
172 if (unlikely(rt)) {
173 resrtextents = qblocks = resaligned;
174 resrtextents /= mp->m_sb.sb_rextsize;
175 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
176 quota_flag = XFS_QMOPT_RES_RTBLKS;
177 } else {
178 resrtextents = 0;
179 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
180 quota_flag = XFS_QMOPT_RES_REGBLKS;
181 }
182
183 /*
184 * Allocate and setup the transaction
185 */
186 tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
187 error = xfs_trans_reserve(tp, resblks,
188 XFS_WRITE_LOG_RES(mp), resrtextents,
189 XFS_TRANS_PERM_LOG_RES,
190 XFS_WRITE_LOG_COUNT);
191 /*
192 * Check for running out of space, note: need lock to return
193 */
194 if (error) {
195 xfs_trans_cancel(tp, 0);
196 return XFS_ERROR(error);
197 }
198
199 xfs_ilock(ip, XFS_ILOCK_EXCL);
200
201 error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
202 if (error)
203 goto out_trans_cancel;
204
205 xfs_trans_ijoin(tp, ip, 0);
206
207 bmapi_flag = 0;
208 if (offset < XFS_ISIZE(ip) || extsz)
209 bmapi_flag |= XFS_BMAPI_PREALLOC;
210
211 /*
212 * From this point onwards we overwrite the imap pointer that the
213 * caller gave to us.
214 */
215 xfs_bmap_init(&free_list, &firstfsb);
216 nimaps = 1;
217 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flag,
218 &firstfsb, 0, imap, &nimaps, &free_list);
219 if (error)
220 goto out_bmap_cancel;
221
222 /*
223 * Complete the transaction
224 */
225 error = xfs_bmap_finish(&tp, &free_list, &committed);
226 if (error)
227 goto out_bmap_cancel;
228 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
229 if (error)
230 goto out_unlock;
231
232 /*
233 * Copy any maps to caller's array and return any error.
234 */
235 if (nimaps == 0) {
236 error = XFS_ERROR(ENOSPC);
237 goto out_unlock;
238 }
239
240 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
241 error = xfs_alert_fsblock_zero(ip, imap);
242
243out_unlock:
244 xfs_iunlock(ip, XFS_ILOCK_EXCL);
245 return error;
246
247out_bmap_cancel:
248 xfs_bmap_cancel(&free_list);
249 xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
250out_trans_cancel:
251 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
252 goto out_unlock;
253}
254
255/*
256 * If the caller is doing a write at the end of the file, then extend the
257 * allocation out to the file system's write iosize. We clean up any extra
258 * space left over when the file is closed in xfs_inactive().
259 *
260 * If we find we already have delalloc preallocation beyond EOF, don't do more
261 * preallocation as it it not needed.
262 */
263STATIC int
264xfs_iomap_eof_want_preallocate(
265 xfs_mount_t *mp,
266 xfs_inode_t *ip,
267 xfs_off_t offset,
268 size_t count,
269 xfs_bmbt_irec_t *imap,
270 int nimaps,
271 int *prealloc)
272{
273 xfs_fileoff_t start_fsb;
274 xfs_filblks_t count_fsb;
275 xfs_fsblock_t firstblock;
276 int n, error, imaps;
277 int found_delalloc = 0;
278
279 *prealloc = 0;
280 if (offset + count <= XFS_ISIZE(ip))
281 return 0;
282
283 /*
284 * If there are any real blocks past eof, then don't
285 * do any speculative allocation.
286 */
287 start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1)));
288 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
289 while (count_fsb > 0) {
290 imaps = nimaps;
291 firstblock = NULLFSBLOCK;
292 error = xfs_bmapi_read(ip, start_fsb, count_fsb, imap, &imaps,
293 0);
294 if (error)
295 return error;
296 for (n = 0; n < imaps; n++) {
297 if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
298 (imap[n].br_startblock != DELAYSTARTBLOCK))
299 return 0;
300 start_fsb += imap[n].br_blockcount;
301 count_fsb -= imap[n].br_blockcount;
302
303 if (imap[n].br_startblock == DELAYSTARTBLOCK)
304 found_delalloc = 1;
305 }
306 }
307 if (!found_delalloc)
308 *prealloc = 1;
309 return 0;
310}
311
312/*
313 * If we don't have a user specified preallocation size, dynamically increase
314 * the preallocation size as the size of the file grows. Cap the maximum size
315 * at a single extent or less if the filesystem is near full. The closer the
316 * filesystem is to full, the smaller the maximum prealocation.
317 */
318STATIC xfs_fsblock_t
319xfs_iomap_prealloc_size(
320 struct xfs_mount *mp,
321 struct xfs_inode *ip)
322{
323 xfs_fsblock_t alloc_blocks = 0;
324
325 if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
326 int shift = 0;
327 int64_t freesp;
328
329 /*
330 * rounddown_pow_of_two() returns an undefined result
331 * if we pass in alloc_blocks = 0. Hence the "+ 1" to
332 * ensure we always pass in a non-zero value.
333 */
334 alloc_blocks = XFS_B_TO_FSB(mp, XFS_ISIZE(ip)) + 1;
335 alloc_blocks = XFS_FILEOFF_MIN(MAXEXTLEN,
336 rounddown_pow_of_two(alloc_blocks));
337
338 xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);
339 freesp = mp->m_sb.sb_fdblocks;
340 if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
341 shift = 2;
342 if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
343 shift++;
344 if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
345 shift++;
346 if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
347 shift++;
348 if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
349 shift++;
350 }
351 if (shift)
352 alloc_blocks >>= shift;
353 }
354
355 if (alloc_blocks < mp->m_writeio_blocks)
356 alloc_blocks = mp->m_writeio_blocks;
357
358 return alloc_blocks;
359}
360
361int
362xfs_iomap_write_delay(
363 xfs_inode_t *ip,
364 xfs_off_t offset,
365 size_t count,
366 xfs_bmbt_irec_t *ret_imap)
367{
368 xfs_mount_t *mp = ip->i_mount;
369 xfs_fileoff_t offset_fsb;
370 xfs_fileoff_t last_fsb;
371 xfs_off_t aligned_offset;
372 xfs_fileoff_t ioalign;
373 xfs_extlen_t extsz;
374 int nimaps;
375 xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
376 int prealloc, flushed = 0;
377 int error;
378
379 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
380
381 /*
382 * Make sure that the dquots are there. This doesn't hold
383 * the ilock across a disk read.
384 */
385 error = xfs_qm_dqattach_locked(ip, 0);
386 if (error)
387 return XFS_ERROR(error);
388
389 extsz = xfs_get_extsz_hint(ip);
390 offset_fsb = XFS_B_TO_FSBT(mp, offset);
391
392
393 error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count,
394 imap, XFS_WRITE_IMAPS, &prealloc);
395 if (error)
396 return error;
397
398retry:
399 if (prealloc) {
400 xfs_fsblock_t alloc_blocks = xfs_iomap_prealloc_size(mp, ip);
401
402 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
403 ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
404 last_fsb = ioalign + alloc_blocks;
405 } else {
406 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
407 }
408
409 if (prealloc || extsz) {
410 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
411 if (error)
412 return error;
413 }
414
415 /*
416 * Make sure preallocation does not create extents beyond the range we
417 * actually support in this filesystem.
418 */
419 if (last_fsb > XFS_B_TO_FSB(mp, mp->m_maxioffset))
420 last_fsb = XFS_B_TO_FSB(mp, mp->m_maxioffset);
421
422 ASSERT(last_fsb > offset_fsb);
423
424 nimaps = XFS_WRITE_IMAPS;
425 error = xfs_bmapi_delay(ip, offset_fsb, last_fsb - offset_fsb,
426 imap, &nimaps, XFS_BMAPI_ENTIRE);
427 switch (error) {
428 case 0:
429 case ENOSPC:
430 case EDQUOT:
431 break;
432 default:
433 return XFS_ERROR(error);
434 }
435
436 /*
437 * If bmapi returned us nothing, we got either ENOSPC or EDQUOT. For
438 * ENOSPC, * flush all other inodes with delalloc blocks to free up
439 * some of the excess reserved metadata space. For both cases, retry
440 * without EOF preallocation.
441 */
442 if (nimaps == 0) {
443 trace_xfs_delalloc_enospc(ip, offset, count);
444 if (flushed)
445 return XFS_ERROR(error ? error : ENOSPC);
446
447 if (error == ENOSPC) {
448 xfs_iunlock(ip, XFS_ILOCK_EXCL);
449 xfs_flush_inodes(ip);
450 xfs_ilock(ip, XFS_ILOCK_EXCL);
451 }
452
453 flushed = 1;
454 error = 0;
455 prealloc = 0;
456 goto retry;
457 }
458
459 if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip)))
460 return xfs_alert_fsblock_zero(ip, &imap[0]);
461
462 *ret_imap = imap[0];
463 return 0;
464}
465
466/*
467 * Pass in a delayed allocate extent, convert it to real extents;
468 * return to the caller the extent we create which maps on top of
469 * the originating callers request.
470 *
471 * Called without a lock on the inode.
472 *
473 * We no longer bother to look at the incoming map - all we have to
474 * guarantee is that whatever we allocate fills the required range.
475 */
476int
477xfs_iomap_write_allocate(
478 xfs_inode_t *ip,
479 xfs_off_t offset,
480 size_t count,
481 xfs_bmbt_irec_t *imap)
482{
483 xfs_mount_t *mp = ip->i_mount;
484 xfs_fileoff_t offset_fsb, last_block;
485 xfs_fileoff_t end_fsb, map_start_fsb;
486 xfs_fsblock_t first_block;
487 xfs_bmap_free_t free_list;
488 xfs_filblks_t count_fsb;
489 xfs_trans_t *tp;
490 int nimaps, committed;
491 int error = 0;
492 int nres;
493
494 /*
495 * Make sure that the dquots are there.
496 */
497 error = xfs_qm_dqattach(ip, 0);
498 if (error)
499 return XFS_ERROR(error);
500
501 offset_fsb = XFS_B_TO_FSBT(mp, offset);
502 count_fsb = imap->br_blockcount;
503 map_start_fsb = imap->br_startoff;
504
505 XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
506
507 while (count_fsb != 0) {
508 /*
509 * Set up a transaction with which to allocate the
510 * backing store for the file. Do allocations in a
511 * loop until we get some space in the range we are
512 * interested in. The other space that might be allocated
513 * is in the delayed allocation extent on which we sit
514 * but before our buffer starts.
515 */
516
517 nimaps = 0;
518 while (nimaps == 0) {
519 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
520 tp->t_flags |= XFS_TRANS_RESERVE;
521 nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
522 error = xfs_trans_reserve(tp, nres,
523 XFS_WRITE_LOG_RES(mp),
524 0, XFS_TRANS_PERM_LOG_RES,
525 XFS_WRITE_LOG_COUNT);
526 if (error) {
527 xfs_trans_cancel(tp, 0);
528 return XFS_ERROR(error);
529 }
530 xfs_ilock(ip, XFS_ILOCK_EXCL);
531 xfs_trans_ijoin(tp, ip, 0);
532
533 xfs_bmap_init(&free_list, &first_block);
534
535 /*
536 * it is possible that the extents have changed since
537 * we did the read call as we dropped the ilock for a
538 * while. We have to be careful about truncates or hole
539 * punchs here - we are not allowed to allocate
540 * non-delalloc blocks here.
541 *
542 * The only protection against truncation is the pages
543 * for the range we are being asked to convert are
544 * locked and hence a truncate will block on them
545 * first.
546 *
547 * As a result, if we go beyond the range we really
548 * need and hit an delalloc extent boundary followed by
549 * a hole while we have excess blocks in the map, we
550 * will fill the hole incorrectly and overrun the
551 * transaction reservation.
552 *
553 * Using a single map prevents this as we are forced to
554 * check each map we look for overlap with the desired
555 * range and abort as soon as we find it. Also, given
556 * that we only return a single map, having one beyond
557 * what we can return is probably a bit silly.
558 *
559 * We also need to check that we don't go beyond EOF;
560 * this is a truncate optimisation as a truncate sets
561 * the new file size before block on the pages we
562 * currently have locked under writeback. Because they
563 * are about to be tossed, we don't need to write them
564 * back....
565 */
566 nimaps = 1;
567 end_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
568 error = xfs_bmap_last_offset(NULL, ip, &last_block,
569 XFS_DATA_FORK);
570 if (error)
571 goto trans_cancel;
572
573 last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
574 if ((map_start_fsb + count_fsb) > last_block) {
575 count_fsb = last_block - map_start_fsb;
576 if (count_fsb == 0) {
577 error = EAGAIN;
578 goto trans_cancel;
579 }
580 }
581
582 /*
583 * From this point onwards we overwrite the imap
584 * pointer that the caller gave to us.
585 */
586 error = xfs_bmapi_write(tp, ip, map_start_fsb,
587 count_fsb, 0, &first_block, 1,
588 imap, &nimaps, &free_list);
589 if (error)
590 goto trans_cancel;
591
592 error = xfs_bmap_finish(&tp, &free_list, &committed);
593 if (error)
594 goto trans_cancel;
595
596 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
597 if (error)
598 goto error0;
599
600 xfs_iunlock(ip, XFS_ILOCK_EXCL);
601 }
602
603 /*
604 * See if we were able to allocate an extent that
605 * covers at least part of the callers request
606 */
607 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
608 return xfs_alert_fsblock_zero(ip, imap);
609
610 if ((offset_fsb >= imap->br_startoff) &&
611 (offset_fsb < (imap->br_startoff +
612 imap->br_blockcount))) {
613 XFS_STATS_INC(xs_xstrat_quick);
614 return 0;
615 }
616
617 /*
618 * So far we have not mapped the requested part of the
619 * file, just surrounding data, try again.
620 */
621 count_fsb -= imap->br_blockcount;
622 map_start_fsb = imap->br_startoff + imap->br_blockcount;
623 }
624
625trans_cancel:
626 xfs_bmap_cancel(&free_list);
627 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
628error0:
629 xfs_iunlock(ip, XFS_ILOCK_EXCL);
630 return XFS_ERROR(error);
631}
632
633int
634xfs_iomap_write_unwritten(
635 xfs_inode_t *ip,
636 xfs_off_t offset,
637 size_t count)
638{
639 xfs_mount_t *mp = ip->i_mount;
640 xfs_fileoff_t offset_fsb;
641 xfs_filblks_t count_fsb;
642 xfs_filblks_t numblks_fsb;
643 xfs_fsblock_t firstfsb;
644 int nimaps;
645 xfs_trans_t *tp;
646 xfs_bmbt_irec_t imap;
647 xfs_bmap_free_t free_list;
648 xfs_fsize_t i_size;
649 uint resblks;
650 int committed;
651 int error;
652
653 trace_xfs_unwritten_convert(ip, offset, count);
654
655 offset_fsb = XFS_B_TO_FSBT(mp, offset);
656 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
657 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
658
659 /*
660 * Reserve enough blocks in this transaction for two complete extent
661 * btree splits. We may be converting the middle part of an unwritten
662 * extent and in this case we will insert two new extents in the btree
663 * each of which could cause a full split.
664 *
665 * This reservation amount will be used in the first call to
666 * xfs_bmbt_split() to select an AG with enough space to satisfy the
667 * rest of the operation.
668 */
669 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
670
671 do {
672 /*
673 * set up a transaction to convert the range of extents
674 * from unwritten to real. Do allocations in a loop until
675 * we have covered the range passed in.
676 *
677 * Note that we open code the transaction allocation here
678 * to pass KM_NOFS--we can't risk to recursing back into
679 * the filesystem here as we might be asked to write out
680 * the same inode that we complete here and might deadlock
681 * on the iolock.
682 */
683 xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);
684 tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS);
685 tp->t_flags |= XFS_TRANS_RESERVE;
686 error = xfs_trans_reserve(tp, resblks,
687 XFS_WRITE_LOG_RES(mp), 0,
688 XFS_TRANS_PERM_LOG_RES,
689 XFS_WRITE_LOG_COUNT);
690 if (error) {
691 xfs_trans_cancel(tp, 0);
692 return XFS_ERROR(error);
693 }
694
695 xfs_ilock(ip, XFS_ILOCK_EXCL);
696 xfs_trans_ijoin(tp, ip, 0);
697
698 /*
699 * Modify the unwritten extent state of the buffer.
700 */
701 xfs_bmap_init(&free_list, &firstfsb);
702 nimaps = 1;
703 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
704 XFS_BMAPI_CONVERT, &firstfsb,
705 1, &imap, &nimaps, &free_list);
706 if (error)
707 goto error_on_bmapi_transaction;
708
709 /*
710 * Log the updated inode size as we go. We have to be careful
711 * to only log it up to the actual write offset if it is
712 * halfway into a block.
713 */
714 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
715 if (i_size > offset + count)
716 i_size = offset + count;
717
718 i_size = xfs_new_eof(ip, i_size);
719 if (i_size) {
720 ip->i_d.di_size = i_size;
721 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
722 }
723
724 error = xfs_bmap_finish(&tp, &free_list, &committed);
725 if (error)
726 goto error_on_bmapi_transaction;
727
728 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
729 xfs_iunlock(ip, XFS_ILOCK_EXCL);
730 if (error)
731 return XFS_ERROR(error);
732
733 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
734 return xfs_alert_fsblock_zero(ip, &imap);
735
736 if ((numblks_fsb = imap.br_blockcount) == 0) {
737 /*
738 * The numblks_fsb value should always get
739 * smaller, otherwise the loop is stuck.
740 */
741 ASSERT(imap.br_blockcount);
742 break;
743 }
744 offset_fsb += numblks_fsb;
745 count_fsb -= numblks_fsb;
746 } while (count_fsb > 0);
747
748 return 0;
749
750error_on_bmapi_transaction:
751 xfs_bmap_cancel(&free_list);
752 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
753 xfs_iunlock(ip, XFS_ILOCK_EXCL);
754 return XFS_ERROR(error);
755}
1/*
2 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
3 * Copyright (c) 2016 Christoph Hellwig.
4 * All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19#include <linux/iomap.h>
20#include "xfs.h"
21#include "xfs_fs.h"
22#include "xfs_shared.h"
23#include "xfs_format.h"
24#include "xfs_log_format.h"
25#include "xfs_trans_resv.h"
26#include "xfs_mount.h"
27#include "xfs_defer.h"
28#include "xfs_inode.h"
29#include "xfs_btree.h"
30#include "xfs_bmap_btree.h"
31#include "xfs_bmap.h"
32#include "xfs_bmap_util.h"
33#include "xfs_errortag.h"
34#include "xfs_error.h"
35#include "xfs_trans.h"
36#include "xfs_trans_space.h"
37#include "xfs_inode_item.h"
38#include "xfs_iomap.h"
39#include "xfs_trace.h"
40#include "xfs_icache.h"
41#include "xfs_quota.h"
42#include "xfs_dquot_item.h"
43#include "xfs_dquot.h"
44#include "xfs_reflink.h"
45
46
47#define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \
48 << mp->m_writeio_log)
49
50void
51xfs_bmbt_to_iomap(
52 struct xfs_inode *ip,
53 struct iomap *iomap,
54 struct xfs_bmbt_irec *imap)
55{
56 struct xfs_mount *mp = ip->i_mount;
57
58 if (imap->br_startblock == HOLESTARTBLOCK) {
59 iomap->addr = IOMAP_NULL_ADDR;
60 iomap->type = IOMAP_HOLE;
61 } else if (imap->br_startblock == DELAYSTARTBLOCK) {
62 iomap->addr = IOMAP_NULL_ADDR;
63 iomap->type = IOMAP_DELALLOC;
64 } else {
65 iomap->addr = BBTOB(xfs_fsb_to_db(ip, imap->br_startblock));
66 if (imap->br_state == XFS_EXT_UNWRITTEN)
67 iomap->type = IOMAP_UNWRITTEN;
68 else
69 iomap->type = IOMAP_MAPPED;
70 }
71 iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
72 iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
73 iomap->bdev = xfs_find_bdev_for_inode(VFS_I(ip));
74 iomap->dax_dev = xfs_find_daxdev_for_inode(VFS_I(ip));
75}
76
77xfs_extlen_t
78xfs_eof_alignment(
79 struct xfs_inode *ip,
80 xfs_extlen_t extsize)
81{
82 struct xfs_mount *mp = ip->i_mount;
83 xfs_extlen_t align = 0;
84
85 if (!XFS_IS_REALTIME_INODE(ip)) {
86 /*
87 * Round up the allocation request to a stripe unit
88 * (m_dalign) boundary if the file size is >= stripe unit
89 * size, and we are allocating past the allocation eof.
90 *
91 * If mounted with the "-o swalloc" option the alignment is
92 * increased from the strip unit size to the stripe width.
93 */
94 if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC))
95 align = mp->m_swidth;
96 else if (mp->m_dalign)
97 align = mp->m_dalign;
98
99 if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
100 align = 0;
101 }
102
103 /*
104 * Always round up the allocation request to an extent boundary
105 * (when file on a real-time subvolume or has di_extsize hint).
106 */
107 if (extsize) {
108 if (align)
109 align = roundup_64(align, extsize);
110 else
111 align = extsize;
112 }
113
114 return align;
115}
116
117STATIC int
118xfs_iomap_eof_align_last_fsb(
119 struct xfs_inode *ip,
120 xfs_extlen_t extsize,
121 xfs_fileoff_t *last_fsb)
122{
123 xfs_extlen_t align = xfs_eof_alignment(ip, extsize);
124
125 if (align) {
126 xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align);
127 int eof, error;
128
129 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
130 if (error)
131 return error;
132 if (eof)
133 *last_fsb = new_last_fsb;
134 }
135 return 0;
136}
137
138STATIC int
139xfs_alert_fsblock_zero(
140 xfs_inode_t *ip,
141 xfs_bmbt_irec_t *imap)
142{
143 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
144 "Access to block zero in inode %llu "
145 "start_block: %llx start_off: %llx "
146 "blkcnt: %llx extent-state: %x",
147 (unsigned long long)ip->i_ino,
148 (unsigned long long)imap->br_startblock,
149 (unsigned long long)imap->br_startoff,
150 (unsigned long long)imap->br_blockcount,
151 imap->br_state);
152 return -EFSCORRUPTED;
153}
154
155int
156xfs_iomap_write_direct(
157 xfs_inode_t *ip,
158 xfs_off_t offset,
159 size_t count,
160 xfs_bmbt_irec_t *imap,
161 int nmaps)
162{
163 xfs_mount_t *mp = ip->i_mount;
164 xfs_fileoff_t offset_fsb;
165 xfs_fileoff_t last_fsb;
166 xfs_filblks_t count_fsb, resaligned;
167 xfs_fsblock_t firstfsb;
168 xfs_extlen_t extsz;
169 int nimaps;
170 int quota_flag;
171 int rt;
172 xfs_trans_t *tp;
173 struct xfs_defer_ops dfops;
174 uint qblocks, resblks, resrtextents;
175 int error;
176 int lockmode;
177 int bmapi_flags = XFS_BMAPI_PREALLOC;
178 uint tflags = 0;
179
180 rt = XFS_IS_REALTIME_INODE(ip);
181 extsz = xfs_get_extsz_hint(ip);
182 lockmode = XFS_ILOCK_SHARED; /* locked by caller */
183
184 ASSERT(xfs_isilocked(ip, lockmode));
185
186 offset_fsb = XFS_B_TO_FSBT(mp, offset);
187 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
188 if ((offset + count) > XFS_ISIZE(ip)) {
189 /*
190 * Assert that the in-core extent list is present since this can
191 * call xfs_iread_extents() and we only have the ilock shared.
192 * This should be safe because the lock was held around a bmapi
193 * call in the caller and we only need it to access the in-core
194 * list.
195 */
196 ASSERT(XFS_IFORK_PTR(ip, XFS_DATA_FORK)->if_flags &
197 XFS_IFEXTENTS);
198 error = xfs_iomap_eof_align_last_fsb(ip, extsz, &last_fsb);
199 if (error)
200 goto out_unlock;
201 } else {
202 if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
203 last_fsb = MIN(last_fsb, (xfs_fileoff_t)
204 imap->br_blockcount +
205 imap->br_startoff);
206 }
207 count_fsb = last_fsb - offset_fsb;
208 ASSERT(count_fsb > 0);
209 resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb, extsz);
210
211 if (unlikely(rt)) {
212 resrtextents = qblocks = resaligned;
213 resrtextents /= mp->m_sb.sb_rextsize;
214 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
215 quota_flag = XFS_QMOPT_RES_RTBLKS;
216 } else {
217 resrtextents = 0;
218 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
219 quota_flag = XFS_QMOPT_RES_REGBLKS;
220 }
221
222 /*
223 * Drop the shared lock acquired by the caller, attach the dquot if
224 * necessary and move on to transaction setup.
225 */
226 xfs_iunlock(ip, lockmode);
227 error = xfs_qm_dqattach(ip, 0);
228 if (error)
229 return error;
230
231 /*
232 * For DAX, we do not allocate unwritten extents, but instead we zero
233 * the block before we commit the transaction. Ideally we'd like to do
234 * this outside the transaction context, but if we commit and then crash
235 * we may not have zeroed the blocks and this will be exposed on
236 * recovery of the allocation. Hence we must zero before commit.
237 *
238 * Further, if we are mapping unwritten extents here, we need to zero
239 * and convert them to written so that we don't need an unwritten extent
240 * callback for DAX. This also means that we need to be able to dip into
241 * the reserve block pool for bmbt block allocation if there is no space
242 * left but we need to do unwritten extent conversion.
243 */
244 if (IS_DAX(VFS_I(ip))) {
245 bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
246 if (imap->br_state == XFS_EXT_UNWRITTEN) {
247 tflags |= XFS_TRANS_RESERVE;
248 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
249 }
250 }
251 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, resrtextents,
252 tflags, &tp);
253 if (error)
254 return error;
255
256 lockmode = XFS_ILOCK_EXCL;
257 xfs_ilock(ip, lockmode);
258
259 error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
260 if (error)
261 goto out_trans_cancel;
262
263 xfs_trans_ijoin(tp, ip, 0);
264
265 /*
266 * From this point onwards we overwrite the imap pointer that the
267 * caller gave to us.
268 */
269 xfs_defer_init(&dfops, &firstfsb);
270 nimaps = 1;
271 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
272 bmapi_flags, &firstfsb, resblks, imap,
273 &nimaps, &dfops);
274 if (error)
275 goto out_bmap_cancel;
276
277 /*
278 * Complete the transaction
279 */
280 error = xfs_defer_finish(&tp, &dfops);
281 if (error)
282 goto out_bmap_cancel;
283
284 error = xfs_trans_commit(tp);
285 if (error)
286 goto out_unlock;
287
288 /*
289 * Copy any maps to caller's array and return any error.
290 */
291 if (nimaps == 0) {
292 error = -ENOSPC;
293 goto out_unlock;
294 }
295
296 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
297 error = xfs_alert_fsblock_zero(ip, imap);
298
299out_unlock:
300 xfs_iunlock(ip, lockmode);
301 return error;
302
303out_bmap_cancel:
304 xfs_defer_cancel(&dfops);
305 xfs_trans_unreserve_quota_nblks(tp, ip, (long)qblocks, 0, quota_flag);
306out_trans_cancel:
307 xfs_trans_cancel(tp);
308 goto out_unlock;
309}
310
311STATIC bool
312xfs_quota_need_throttle(
313 struct xfs_inode *ip,
314 int type,
315 xfs_fsblock_t alloc_blocks)
316{
317 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
318
319 if (!dq || !xfs_this_quota_on(ip->i_mount, type))
320 return false;
321
322 /* no hi watermark, no throttle */
323 if (!dq->q_prealloc_hi_wmark)
324 return false;
325
326 /* under the lo watermark, no throttle */
327 if (dq->q_res_bcount + alloc_blocks < dq->q_prealloc_lo_wmark)
328 return false;
329
330 return true;
331}
332
333STATIC void
334xfs_quota_calc_throttle(
335 struct xfs_inode *ip,
336 int type,
337 xfs_fsblock_t *qblocks,
338 int *qshift,
339 int64_t *qfreesp)
340{
341 int64_t freesp;
342 int shift = 0;
343 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
344
345 /* no dq, or over hi wmark, squash the prealloc completely */
346 if (!dq || dq->q_res_bcount >= dq->q_prealloc_hi_wmark) {
347 *qblocks = 0;
348 *qfreesp = 0;
349 return;
350 }
351
352 freesp = dq->q_prealloc_hi_wmark - dq->q_res_bcount;
353 if (freesp < dq->q_low_space[XFS_QLOWSP_5_PCNT]) {
354 shift = 2;
355 if (freesp < dq->q_low_space[XFS_QLOWSP_3_PCNT])
356 shift += 2;
357 if (freesp < dq->q_low_space[XFS_QLOWSP_1_PCNT])
358 shift += 2;
359 }
360
361 if (freesp < *qfreesp)
362 *qfreesp = freesp;
363
364 /* only overwrite the throttle values if we are more aggressive */
365 if ((freesp >> shift) < (*qblocks >> *qshift)) {
366 *qblocks = freesp;
367 *qshift = shift;
368 }
369}
370
371/*
372 * If we are doing a write at the end of the file and there are no allocations
373 * past this one, then extend the allocation out to the file system's write
374 * iosize.
375 *
376 * If we don't have a user specified preallocation size, dynamically increase
377 * the preallocation size as the size of the file grows. Cap the maximum size
378 * at a single extent or less if the filesystem is near full. The closer the
379 * filesystem is to full, the smaller the maximum prealocation.
380 *
381 * As an exception we don't do any preallocation at all if the file is smaller
382 * than the minimum preallocation and we are using the default dynamic
383 * preallocation scheme, as it is likely this is the only write to the file that
384 * is going to be done.
385 *
386 * We clean up any extra space left over when the file is closed in
387 * xfs_inactive().
388 */
389STATIC xfs_fsblock_t
390xfs_iomap_prealloc_size(
391 struct xfs_inode *ip,
392 loff_t offset,
393 loff_t count,
394 struct xfs_iext_cursor *icur)
395{
396 struct xfs_mount *mp = ip->i_mount;
397 struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
398 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
399 struct xfs_bmbt_irec prev;
400 int shift = 0;
401 int64_t freesp;
402 xfs_fsblock_t qblocks;
403 int qshift = 0;
404 xfs_fsblock_t alloc_blocks = 0;
405
406 if (offset + count <= XFS_ISIZE(ip))
407 return 0;
408
409 if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) &&
410 (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_writeio_blocks)))
411 return 0;
412
413 /*
414 * If an explicit allocsize is set, the file is small, or we
415 * are writing behind a hole, then use the minimum prealloc:
416 */
417 if ((mp->m_flags & XFS_MOUNT_DFLT_IOSIZE) ||
418 XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
419 !xfs_iext_peek_prev_extent(ifp, icur, &prev) ||
420 prev.br_startoff + prev.br_blockcount < offset_fsb)
421 return mp->m_writeio_blocks;
422
423 /*
424 * Determine the initial size of the preallocation. We are beyond the
425 * current EOF here, but we need to take into account whether this is
426 * a sparse write or an extending write when determining the
427 * preallocation size. Hence we need to look up the extent that ends
428 * at the current write offset and use the result to determine the
429 * preallocation size.
430 *
431 * If the extent is a hole, then preallocation is essentially disabled.
432 * Otherwise we take the size of the preceding data extent as the basis
433 * for the preallocation size. If the size of the extent is greater than
434 * half the maximum extent length, then use the current offset as the
435 * basis. This ensures that for large files the preallocation size
436 * always extends to MAXEXTLEN rather than falling short due to things
437 * like stripe unit/width alignment of real extents.
438 */
439 if (prev.br_blockcount <= (MAXEXTLEN >> 1))
440 alloc_blocks = prev.br_blockcount << 1;
441 else
442 alloc_blocks = XFS_B_TO_FSB(mp, offset);
443 if (!alloc_blocks)
444 goto check_writeio;
445 qblocks = alloc_blocks;
446
447 /*
448 * MAXEXTLEN is not a power of two value but we round the prealloc down
449 * to the nearest power of two value after throttling. To prevent the
450 * round down from unconditionally reducing the maximum supported prealloc
451 * size, we round up first, apply appropriate throttling, round down and
452 * cap the value to MAXEXTLEN.
453 */
454 alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(MAXEXTLEN),
455 alloc_blocks);
456
457 freesp = percpu_counter_read_positive(&mp->m_fdblocks);
458 if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
459 shift = 2;
460 if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
461 shift++;
462 if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
463 shift++;
464 if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
465 shift++;
466 if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
467 shift++;
468 }
469
470 /*
471 * Check each quota to cap the prealloc size, provide a shift value to
472 * throttle with and adjust amount of available space.
473 */
474 if (xfs_quota_need_throttle(ip, XFS_DQ_USER, alloc_blocks))
475 xfs_quota_calc_throttle(ip, XFS_DQ_USER, &qblocks, &qshift,
476 &freesp);
477 if (xfs_quota_need_throttle(ip, XFS_DQ_GROUP, alloc_blocks))
478 xfs_quota_calc_throttle(ip, XFS_DQ_GROUP, &qblocks, &qshift,
479 &freesp);
480 if (xfs_quota_need_throttle(ip, XFS_DQ_PROJ, alloc_blocks))
481 xfs_quota_calc_throttle(ip, XFS_DQ_PROJ, &qblocks, &qshift,
482 &freesp);
483
484 /*
485 * The final prealloc size is set to the minimum of free space available
486 * in each of the quotas and the overall filesystem.
487 *
488 * The shift throttle value is set to the maximum value as determined by
489 * the global low free space values and per-quota low free space values.
490 */
491 alloc_blocks = MIN(alloc_blocks, qblocks);
492 shift = MAX(shift, qshift);
493
494 if (shift)
495 alloc_blocks >>= shift;
496 /*
497 * rounddown_pow_of_two() returns an undefined result if we pass in
498 * alloc_blocks = 0.
499 */
500 if (alloc_blocks)
501 alloc_blocks = rounddown_pow_of_two(alloc_blocks);
502 if (alloc_blocks > MAXEXTLEN)
503 alloc_blocks = MAXEXTLEN;
504
505 /*
506 * If we are still trying to allocate more space than is
507 * available, squash the prealloc hard. This can happen if we
508 * have a large file on a small filesystem and the above
509 * lowspace thresholds are smaller than MAXEXTLEN.
510 */
511 while (alloc_blocks && alloc_blocks >= freesp)
512 alloc_blocks >>= 4;
513check_writeio:
514 if (alloc_blocks < mp->m_writeio_blocks)
515 alloc_blocks = mp->m_writeio_blocks;
516 trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
517 mp->m_writeio_blocks);
518 return alloc_blocks;
519}
520
521static int
522xfs_file_iomap_begin_delay(
523 struct inode *inode,
524 loff_t offset,
525 loff_t count,
526 struct iomap *iomap)
527{
528 struct xfs_inode *ip = XFS_I(inode);
529 struct xfs_mount *mp = ip->i_mount;
530 struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
531 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
532 xfs_fileoff_t maxbytes_fsb =
533 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes);
534 xfs_fileoff_t end_fsb;
535 int error = 0, eof = 0;
536 struct xfs_bmbt_irec got;
537 struct xfs_iext_cursor icur;
538 xfs_fsblock_t prealloc_blocks = 0;
539
540 ASSERT(!XFS_IS_REALTIME_INODE(ip));
541 ASSERT(!xfs_get_extsz_hint(ip));
542
543 xfs_ilock(ip, XFS_ILOCK_EXCL);
544
545 if (unlikely(XFS_TEST_ERROR(
546 (XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_EXTENTS &&
547 XFS_IFORK_FORMAT(ip, XFS_DATA_FORK) != XFS_DINODE_FMT_BTREE),
548 mp, XFS_ERRTAG_BMAPIFORMAT))) {
549 XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
550 error = -EFSCORRUPTED;
551 goto out_unlock;
552 }
553
554 XFS_STATS_INC(mp, xs_blk_mapw);
555
556 if (!(ifp->if_flags & XFS_IFEXTENTS)) {
557 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
558 if (error)
559 goto out_unlock;
560 }
561
562 eof = !xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got);
563 if (!eof && got.br_startoff <= offset_fsb) {
564 if (xfs_is_reflink_inode(ip)) {
565 bool shared;
566
567 end_fsb = min(XFS_B_TO_FSB(mp, offset + count),
568 maxbytes_fsb);
569 xfs_trim_extent(&got, offset_fsb, end_fsb - offset_fsb);
570 error = xfs_reflink_reserve_cow(ip, &got, &shared);
571 if (error)
572 goto out_unlock;
573 }
574
575 trace_xfs_iomap_found(ip, offset, count, 0, &got);
576 goto done;
577 }
578
579 error = xfs_qm_dqattach_locked(ip, 0);
580 if (error)
581 goto out_unlock;
582
583 /*
584 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES pages
585 * to keep the chunks of work done where somewhat symmetric with the
586 * work writeback does. This is a completely arbitrary number pulled
587 * out of thin air as a best guess for initial testing.
588 *
589 * Note that the values needs to be less than 32-bits wide until
590 * the lower level functions are updated.
591 */
592 count = min_t(loff_t, count, 1024 * PAGE_SIZE);
593 end_fsb = min(XFS_B_TO_FSB(mp, offset + count), maxbytes_fsb);
594
595 if (eof) {
596 prealloc_blocks = xfs_iomap_prealloc_size(ip, offset, count,
597 &icur);
598 if (prealloc_blocks) {
599 xfs_extlen_t align;
600 xfs_off_t end_offset;
601 xfs_fileoff_t p_end_fsb;
602
603 end_offset = XFS_WRITEIO_ALIGN(mp, offset + count - 1);
604 p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
605 prealloc_blocks;
606
607 align = xfs_eof_alignment(ip, 0);
608 if (align)
609 p_end_fsb = roundup_64(p_end_fsb, align);
610
611 p_end_fsb = min(p_end_fsb, maxbytes_fsb);
612 ASSERT(p_end_fsb > offset_fsb);
613 prealloc_blocks = p_end_fsb - end_fsb;
614 }
615 }
616
617retry:
618 error = xfs_bmapi_reserve_delalloc(ip, XFS_DATA_FORK, offset_fsb,
619 end_fsb - offset_fsb, prealloc_blocks, &got, &icur,
620 eof);
621 switch (error) {
622 case 0:
623 break;
624 case -ENOSPC:
625 case -EDQUOT:
626 /* retry without any preallocation */
627 trace_xfs_delalloc_enospc(ip, offset, count);
628 if (prealloc_blocks) {
629 prealloc_blocks = 0;
630 goto retry;
631 }
632 /*FALLTHRU*/
633 default:
634 goto out_unlock;
635 }
636
637 /*
638 * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
639 * them out if the write happens to fail.
640 */
641 iomap->flags = IOMAP_F_NEW;
642 trace_xfs_iomap_alloc(ip, offset, count, 0, &got);
643done:
644 if (isnullstartblock(got.br_startblock))
645 got.br_startblock = DELAYSTARTBLOCK;
646
647 if (!got.br_startblock) {
648 error = xfs_alert_fsblock_zero(ip, &got);
649 if (error)
650 goto out_unlock;
651 }
652
653 xfs_bmbt_to_iomap(ip, iomap, &got);
654
655out_unlock:
656 xfs_iunlock(ip, XFS_ILOCK_EXCL);
657 return error;
658}
659
660/*
661 * Pass in a delayed allocate extent, convert it to real extents;
662 * return to the caller the extent we create which maps on top of
663 * the originating callers request.
664 *
665 * Called without a lock on the inode.
666 *
667 * We no longer bother to look at the incoming map - all we have to
668 * guarantee is that whatever we allocate fills the required range.
669 */
670int
671xfs_iomap_write_allocate(
672 xfs_inode_t *ip,
673 int whichfork,
674 xfs_off_t offset,
675 xfs_bmbt_irec_t *imap)
676{
677 xfs_mount_t *mp = ip->i_mount;
678 xfs_fileoff_t offset_fsb, last_block;
679 xfs_fileoff_t end_fsb, map_start_fsb;
680 xfs_fsblock_t first_block;
681 struct xfs_defer_ops dfops;
682 xfs_filblks_t count_fsb;
683 xfs_trans_t *tp;
684 int nimaps;
685 int error = 0;
686 int flags = XFS_BMAPI_DELALLOC;
687 int nres;
688
689 if (whichfork == XFS_COW_FORK)
690 flags |= XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC;
691
692 /*
693 * Make sure that the dquots are there.
694 */
695 error = xfs_qm_dqattach(ip, 0);
696 if (error)
697 return error;
698
699 offset_fsb = XFS_B_TO_FSBT(mp, offset);
700 count_fsb = imap->br_blockcount;
701 map_start_fsb = imap->br_startoff;
702
703 XFS_STATS_ADD(mp, xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
704
705 while (count_fsb != 0) {
706 /*
707 * Set up a transaction with which to allocate the
708 * backing store for the file. Do allocations in a
709 * loop until we get some space in the range we are
710 * interested in. The other space that might be allocated
711 * is in the delayed allocation extent on which we sit
712 * but before our buffer starts.
713 */
714 nimaps = 0;
715 while (nimaps == 0) {
716 nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
717 /*
718 * We have already reserved space for the extent and any
719 * indirect blocks when creating the delalloc extent,
720 * there is no need to reserve space in this transaction
721 * again.
722 */
723 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0,
724 0, XFS_TRANS_RESERVE, &tp);
725 if (error)
726 return error;
727
728 xfs_ilock(ip, XFS_ILOCK_EXCL);
729 xfs_trans_ijoin(tp, ip, 0);
730
731 xfs_defer_init(&dfops, &first_block);
732
733 /*
734 * it is possible that the extents have changed since
735 * we did the read call as we dropped the ilock for a
736 * while. We have to be careful about truncates or hole
737 * punchs here - we are not allowed to allocate
738 * non-delalloc blocks here.
739 *
740 * The only protection against truncation is the pages
741 * for the range we are being asked to convert are
742 * locked and hence a truncate will block on them
743 * first.
744 *
745 * As a result, if we go beyond the range we really
746 * need and hit an delalloc extent boundary followed by
747 * a hole while we have excess blocks in the map, we
748 * will fill the hole incorrectly and overrun the
749 * transaction reservation.
750 *
751 * Using a single map prevents this as we are forced to
752 * check each map we look for overlap with the desired
753 * range and abort as soon as we find it. Also, given
754 * that we only return a single map, having one beyond
755 * what we can return is probably a bit silly.
756 *
757 * We also need to check that we don't go beyond EOF;
758 * this is a truncate optimisation as a truncate sets
759 * the new file size before block on the pages we
760 * currently have locked under writeback. Because they
761 * are about to be tossed, we don't need to write them
762 * back....
763 */
764 nimaps = 1;
765 end_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
766 error = xfs_bmap_last_offset(ip, &last_block,
767 XFS_DATA_FORK);
768 if (error)
769 goto trans_cancel;
770
771 last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
772 if ((map_start_fsb + count_fsb) > last_block) {
773 count_fsb = last_block - map_start_fsb;
774 if (count_fsb == 0) {
775 error = -EAGAIN;
776 goto trans_cancel;
777 }
778 }
779
780 /*
781 * From this point onwards we overwrite the imap
782 * pointer that the caller gave to us.
783 */
784 error = xfs_bmapi_write(tp, ip, map_start_fsb,
785 count_fsb, flags, &first_block,
786 nres, imap, &nimaps,
787 &dfops);
788 if (error)
789 goto trans_cancel;
790
791 error = xfs_defer_finish(&tp, &dfops);
792 if (error)
793 goto trans_cancel;
794
795 error = xfs_trans_commit(tp);
796 if (error)
797 goto error0;
798
799 xfs_iunlock(ip, XFS_ILOCK_EXCL);
800 }
801
802 /*
803 * See if we were able to allocate an extent that
804 * covers at least part of the callers request
805 */
806 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
807 return xfs_alert_fsblock_zero(ip, imap);
808
809 if ((offset_fsb >= imap->br_startoff) &&
810 (offset_fsb < (imap->br_startoff +
811 imap->br_blockcount))) {
812 XFS_STATS_INC(mp, xs_xstrat_quick);
813 return 0;
814 }
815
816 /*
817 * So far we have not mapped the requested part of the
818 * file, just surrounding data, try again.
819 */
820 count_fsb -= imap->br_blockcount;
821 map_start_fsb = imap->br_startoff + imap->br_blockcount;
822 }
823
824trans_cancel:
825 xfs_defer_cancel(&dfops);
826 xfs_trans_cancel(tp);
827error0:
828 xfs_iunlock(ip, XFS_ILOCK_EXCL);
829 return error;
830}
831
832int
833xfs_iomap_write_unwritten(
834 xfs_inode_t *ip,
835 xfs_off_t offset,
836 xfs_off_t count,
837 bool update_isize)
838{
839 xfs_mount_t *mp = ip->i_mount;
840 xfs_fileoff_t offset_fsb;
841 xfs_filblks_t count_fsb;
842 xfs_filblks_t numblks_fsb;
843 xfs_fsblock_t firstfsb;
844 int nimaps;
845 xfs_trans_t *tp;
846 xfs_bmbt_irec_t imap;
847 struct xfs_defer_ops dfops;
848 struct inode *inode = VFS_I(ip);
849 xfs_fsize_t i_size;
850 uint resblks;
851 int error;
852
853 trace_xfs_unwritten_convert(ip, offset, count);
854
855 offset_fsb = XFS_B_TO_FSBT(mp, offset);
856 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
857 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
858
859 /*
860 * Reserve enough blocks in this transaction for two complete extent
861 * btree splits. We may be converting the middle part of an unwritten
862 * extent and in this case we will insert two new extents in the btree
863 * each of which could cause a full split.
864 *
865 * This reservation amount will be used in the first call to
866 * xfs_bmbt_split() to select an AG with enough space to satisfy the
867 * rest of the operation.
868 */
869 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
870
871 do {
872 /*
873 * Set up a transaction to convert the range of extents
874 * from unwritten to real. Do allocations in a loop until
875 * we have covered the range passed in.
876 *
877 * Note that we can't risk to recursing back into the filesystem
878 * here as we might be asked to write out the same inode that we
879 * complete here and might deadlock on the iolock.
880 */
881 error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0,
882 XFS_TRANS_RESERVE | XFS_TRANS_NOFS, &tp);
883 if (error)
884 return error;
885
886 xfs_ilock(ip, XFS_ILOCK_EXCL);
887 xfs_trans_ijoin(tp, ip, 0);
888
889 /*
890 * Modify the unwritten extent state of the buffer.
891 */
892 xfs_defer_init(&dfops, &firstfsb);
893 nimaps = 1;
894 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
895 XFS_BMAPI_CONVERT, &firstfsb, resblks,
896 &imap, &nimaps, &dfops);
897 if (error)
898 goto error_on_bmapi_transaction;
899
900 /*
901 * Log the updated inode size as we go. We have to be careful
902 * to only log it up to the actual write offset if it is
903 * halfway into a block.
904 */
905 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
906 if (i_size > offset + count)
907 i_size = offset + count;
908 if (update_isize && i_size > i_size_read(inode))
909 i_size_write(inode, i_size);
910 i_size = xfs_new_eof(ip, i_size);
911 if (i_size) {
912 ip->i_d.di_size = i_size;
913 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
914 }
915
916 error = xfs_defer_finish(&tp, &dfops);
917 if (error)
918 goto error_on_bmapi_transaction;
919
920 error = xfs_trans_commit(tp);
921 xfs_iunlock(ip, XFS_ILOCK_EXCL);
922 if (error)
923 return error;
924
925 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
926 return xfs_alert_fsblock_zero(ip, &imap);
927
928 if ((numblks_fsb = imap.br_blockcount) == 0) {
929 /*
930 * The numblks_fsb value should always get
931 * smaller, otherwise the loop is stuck.
932 */
933 ASSERT(imap.br_blockcount);
934 break;
935 }
936 offset_fsb += numblks_fsb;
937 count_fsb -= numblks_fsb;
938 } while (count_fsb > 0);
939
940 return 0;
941
942error_on_bmapi_transaction:
943 xfs_defer_cancel(&dfops);
944 xfs_trans_cancel(tp);
945 xfs_iunlock(ip, XFS_ILOCK_EXCL);
946 return error;
947}
948
949static inline bool imap_needs_alloc(struct inode *inode,
950 struct xfs_bmbt_irec *imap, int nimaps)
951{
952 return !nimaps ||
953 imap->br_startblock == HOLESTARTBLOCK ||
954 imap->br_startblock == DELAYSTARTBLOCK ||
955 (IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN);
956}
957
958static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps)
959{
960 return nimaps &&
961 imap->br_startblock != HOLESTARTBLOCK &&
962 imap->br_state != XFS_EXT_UNWRITTEN;
963}
964
965static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags)
966{
967 /*
968 * COW writes may allocate delalloc space or convert unwritten COW
969 * extents, so we need to make sure to take the lock exclusively here.
970 */
971 if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO)))
972 return true;
973
974 /*
975 * Extents not yet cached requires exclusive access, don't block.
976 * This is an opencoded xfs_ilock_data_map_shared() to cater for the
977 * non-blocking behaviour.
978 */
979 if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
980 !(ip->i_df.if_flags & XFS_IFEXTENTS))
981 return true;
982 return false;
983}
984
985static int
986xfs_file_iomap_begin(
987 struct inode *inode,
988 loff_t offset,
989 loff_t length,
990 unsigned flags,
991 struct iomap *iomap)
992{
993 struct xfs_inode *ip = XFS_I(inode);
994 struct xfs_mount *mp = ip->i_mount;
995 struct xfs_bmbt_irec imap;
996 xfs_fileoff_t offset_fsb, end_fsb;
997 int nimaps = 1, error = 0;
998 bool shared = false, trimmed = false;
999 unsigned lockmode;
1000
1001 if (XFS_FORCED_SHUTDOWN(mp))
1002 return -EIO;
1003
1004 if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) &&
1005 !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
1006 /* Reserve delalloc blocks for regular writeback. */
1007 return xfs_file_iomap_begin_delay(inode, offset, length, iomap);
1008 }
1009
1010 if (need_excl_ilock(ip, flags))
1011 lockmode = XFS_ILOCK_EXCL;
1012 else
1013 lockmode = XFS_ILOCK_SHARED;
1014
1015 if (flags & IOMAP_NOWAIT) {
1016 if (!(ip->i_df.if_flags & XFS_IFEXTENTS))
1017 return -EAGAIN;
1018 if (!xfs_ilock_nowait(ip, lockmode))
1019 return -EAGAIN;
1020 } else {
1021 xfs_ilock(ip, lockmode);
1022 }
1023
1024 ASSERT(offset <= mp->m_super->s_maxbytes);
1025 if (offset > mp->m_super->s_maxbytes - length)
1026 length = mp->m_super->s_maxbytes - offset;
1027 offset_fsb = XFS_B_TO_FSBT(mp, offset);
1028 end_fsb = XFS_B_TO_FSB(mp, offset + length);
1029
1030 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1031 &nimaps, 0);
1032 if (error)
1033 goto out_unlock;
1034
1035 if (flags & IOMAP_REPORT) {
1036 /* Trim the mapping to the nearest shared extent boundary. */
1037 error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
1038 &trimmed);
1039 if (error)
1040 goto out_unlock;
1041 }
1042
1043 if (xfs_is_reflink_inode(ip) &&
1044 ((flags & IOMAP_WRITE) ||
1045 ((flags & IOMAP_ZERO) && needs_cow_for_zeroing(&imap, nimaps)))) {
1046 if (flags & IOMAP_DIRECT) {
1047 /*
1048 * A reflinked inode will result in CoW alloc.
1049 * FIXME: It could still overwrite on unshared extents
1050 * and not need allocation.
1051 */
1052 if (flags & IOMAP_NOWAIT) {
1053 error = -EAGAIN;
1054 goto out_unlock;
1055 }
1056 /* may drop and re-acquire the ilock */
1057 error = xfs_reflink_allocate_cow(ip, &imap, &shared,
1058 &lockmode);
1059 if (error)
1060 goto out_unlock;
1061 } else {
1062 error = xfs_reflink_reserve_cow(ip, &imap, &shared);
1063 if (error)
1064 goto out_unlock;
1065 }
1066
1067 end_fsb = imap.br_startoff + imap.br_blockcount;
1068 length = XFS_FSB_TO_B(mp, end_fsb) - offset;
1069 }
1070
1071 if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {
1072 /*
1073 * If nowait is set bail since we are going to make
1074 * allocations.
1075 */
1076 if (flags & IOMAP_NOWAIT) {
1077 error = -EAGAIN;
1078 goto out_unlock;
1079 }
1080 /*
1081 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1082 * pages to keep the chunks of work done where somewhat symmetric
1083 * with the work writeback does. This is a completely arbitrary
1084 * number pulled out of thin air as a best guess for initial
1085 * testing.
1086 *
1087 * Note that the values needs to be less than 32-bits wide until
1088 * the lower level functions are updated.
1089 */
1090 length = min_t(loff_t, length, 1024 * PAGE_SIZE);
1091 /*
1092 * xfs_iomap_write_direct() expects the shared lock. It
1093 * is unlocked on return.
1094 */
1095 if (lockmode == XFS_ILOCK_EXCL)
1096 xfs_ilock_demote(ip, lockmode);
1097 error = xfs_iomap_write_direct(ip, offset, length, &imap,
1098 nimaps);
1099 if (error)
1100 return error;
1101
1102 iomap->flags = IOMAP_F_NEW;
1103 trace_xfs_iomap_alloc(ip, offset, length, 0, &imap);
1104 } else {
1105 ASSERT(nimaps);
1106
1107 xfs_iunlock(ip, lockmode);
1108 trace_xfs_iomap_found(ip, offset, length, 0, &imap);
1109 }
1110
1111 if (xfs_ipincount(ip) && (ip->i_itemp->ili_fsync_fields
1112 & ~XFS_ILOG_TIMESTAMP))
1113 iomap->flags |= IOMAP_F_DIRTY;
1114
1115 xfs_bmbt_to_iomap(ip, iomap, &imap);
1116
1117 if (shared)
1118 iomap->flags |= IOMAP_F_SHARED;
1119 return 0;
1120out_unlock:
1121 xfs_iunlock(ip, lockmode);
1122 return error;
1123}
1124
1125static int
1126xfs_file_iomap_end_delalloc(
1127 struct xfs_inode *ip,
1128 loff_t offset,
1129 loff_t length,
1130 ssize_t written,
1131 struct iomap *iomap)
1132{
1133 struct xfs_mount *mp = ip->i_mount;
1134 xfs_fileoff_t start_fsb;
1135 xfs_fileoff_t end_fsb;
1136 int error = 0;
1137
1138 /*
1139 * Behave as if the write failed if drop writes is enabled. Set the NEW
1140 * flag to force delalloc cleanup.
1141 */
1142 if (XFS_TEST_ERROR(false, mp, XFS_ERRTAG_DROP_WRITES)) {
1143 iomap->flags |= IOMAP_F_NEW;
1144 written = 0;
1145 }
1146
1147 /*
1148 * start_fsb refers to the first unused block after a short write. If
1149 * nothing was written, round offset down to point at the first block in
1150 * the range.
1151 */
1152 if (unlikely(!written))
1153 start_fsb = XFS_B_TO_FSBT(mp, offset);
1154 else
1155 start_fsb = XFS_B_TO_FSB(mp, offset + written);
1156 end_fsb = XFS_B_TO_FSB(mp, offset + length);
1157
1158 /*
1159 * Trim delalloc blocks if they were allocated by this write and we
1160 * didn't manage to write the whole range.
1161 *
1162 * We don't need to care about racing delalloc as we hold i_mutex
1163 * across the reserve/allocate/unreserve calls. If there are delalloc
1164 * blocks in the range, they are ours.
1165 */
1166 if ((iomap->flags & IOMAP_F_NEW) && start_fsb < end_fsb) {
1167 truncate_pagecache_range(VFS_I(ip), XFS_FSB_TO_B(mp, start_fsb),
1168 XFS_FSB_TO_B(mp, end_fsb) - 1);
1169
1170 xfs_ilock(ip, XFS_ILOCK_EXCL);
1171 error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
1172 end_fsb - start_fsb);
1173 xfs_iunlock(ip, XFS_ILOCK_EXCL);
1174
1175 if (error && !XFS_FORCED_SHUTDOWN(mp)) {
1176 xfs_alert(mp, "%s: unable to clean up ino %lld",
1177 __func__, ip->i_ino);
1178 return error;
1179 }
1180 }
1181
1182 return 0;
1183}
1184
1185static int
1186xfs_file_iomap_end(
1187 struct inode *inode,
1188 loff_t offset,
1189 loff_t length,
1190 ssize_t written,
1191 unsigned flags,
1192 struct iomap *iomap)
1193{
1194 if ((flags & IOMAP_WRITE) && iomap->type == IOMAP_DELALLOC)
1195 return xfs_file_iomap_end_delalloc(XFS_I(inode), offset,
1196 length, written, iomap);
1197 return 0;
1198}
1199
1200const struct iomap_ops xfs_iomap_ops = {
1201 .iomap_begin = xfs_file_iomap_begin,
1202 .iomap_end = xfs_file_iomap_end,
1203};
1204
1205static int
1206xfs_xattr_iomap_begin(
1207 struct inode *inode,
1208 loff_t offset,
1209 loff_t length,
1210 unsigned flags,
1211 struct iomap *iomap)
1212{
1213 struct xfs_inode *ip = XFS_I(inode);
1214 struct xfs_mount *mp = ip->i_mount;
1215 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1216 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1217 struct xfs_bmbt_irec imap;
1218 int nimaps = 1, error = 0;
1219 unsigned lockmode;
1220
1221 if (XFS_FORCED_SHUTDOWN(mp))
1222 return -EIO;
1223
1224 lockmode = xfs_ilock_attr_map_shared(ip);
1225
1226 /* if there are no attribute fork or extents, return ENOENT */
1227 if (!XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
1228 error = -ENOENT;
1229 goto out_unlock;
1230 }
1231
1232 ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL);
1233 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1234 &nimaps, XFS_BMAPI_ATTRFORK);
1235out_unlock:
1236 xfs_iunlock(ip, lockmode);
1237
1238 if (!error) {
1239 ASSERT(nimaps);
1240 xfs_bmbt_to_iomap(ip, iomap, &imap);
1241 }
1242
1243 return error;
1244}
1245
1246const struct iomap_ops xfs_xattr_iomap_ops = {
1247 .iomap_begin = xfs_xattr_iomap_begin,
1248};