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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};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
4 * Copyright (c) 2016-2018 Christoph Hellwig.
5 * All Rights Reserved.
6 */
7#include "xfs.h"
8#include "xfs_fs.h"
9#include "xfs_shared.h"
10#include "xfs_format.h"
11#include "xfs_log_format.h"
12#include "xfs_trans_resv.h"
13#include "xfs_mount.h"
14#include "xfs_inode.h"
15#include "xfs_btree.h"
16#include "xfs_bmap_btree.h"
17#include "xfs_bmap.h"
18#include "xfs_bmap_util.h"
19#include "xfs_errortag.h"
20#include "xfs_error.h"
21#include "xfs_trans.h"
22#include "xfs_trans_space.h"
23#include "xfs_inode_item.h"
24#include "xfs_iomap.h"
25#include "xfs_trace.h"
26#include "xfs_quota.h"
27#include "xfs_rtgroup.h"
28#include "xfs_dquot_item.h"
29#include "xfs_dquot.h"
30#include "xfs_reflink.h"
31#include "xfs_health.h"
32#include "xfs_rtbitmap.h"
33
34#define XFS_ALLOC_ALIGN(mp, off) \
35 (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log)
36
37static int
38xfs_alert_fsblock_zero(
39 xfs_inode_t *ip,
40 xfs_bmbt_irec_t *imap)
41{
42 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
43 "Access to block zero in inode %llu "
44 "start_block: %llx start_off: %llx "
45 "blkcnt: %llx extent-state: %x",
46 (unsigned long long)ip->i_ino,
47 (unsigned long long)imap->br_startblock,
48 (unsigned long long)imap->br_startoff,
49 (unsigned long long)imap->br_blockcount,
50 imap->br_state);
51 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
52 return -EFSCORRUPTED;
53}
54
55u64
56xfs_iomap_inode_sequence(
57 struct xfs_inode *ip,
58 u16 iomap_flags)
59{
60 u64 cookie = 0;
61
62 if (iomap_flags & IOMAP_F_XATTR)
63 return READ_ONCE(ip->i_af.if_seq);
64 if ((iomap_flags & IOMAP_F_SHARED) && ip->i_cowfp)
65 cookie = (u64)READ_ONCE(ip->i_cowfp->if_seq) << 32;
66 return cookie | READ_ONCE(ip->i_df.if_seq);
67}
68
69/*
70 * Check that the iomap passed to us is still valid for the given offset and
71 * length.
72 */
73static bool
74xfs_iomap_valid(
75 struct inode *inode,
76 const struct iomap *iomap)
77{
78 struct xfs_inode *ip = XFS_I(inode);
79
80 if (iomap->validity_cookie !=
81 xfs_iomap_inode_sequence(ip, iomap->flags)) {
82 trace_xfs_iomap_invalid(ip, iomap);
83 return false;
84 }
85
86 XFS_ERRORTAG_DELAY(ip->i_mount, XFS_ERRTAG_WRITE_DELAY_MS);
87 return true;
88}
89
90static const struct iomap_folio_ops xfs_iomap_folio_ops = {
91 .iomap_valid = xfs_iomap_valid,
92};
93
94int
95xfs_bmbt_to_iomap(
96 struct xfs_inode *ip,
97 struct iomap *iomap,
98 struct xfs_bmbt_irec *imap,
99 unsigned int mapping_flags,
100 u16 iomap_flags,
101 u64 sequence_cookie)
102{
103 struct xfs_mount *mp = ip->i_mount;
104 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
105
106 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
107 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
108 return xfs_alert_fsblock_zero(ip, imap);
109 }
110
111 if (imap->br_startblock == HOLESTARTBLOCK) {
112 iomap->addr = IOMAP_NULL_ADDR;
113 iomap->type = IOMAP_HOLE;
114 } else if (imap->br_startblock == DELAYSTARTBLOCK ||
115 isnullstartblock(imap->br_startblock)) {
116 iomap->addr = IOMAP_NULL_ADDR;
117 iomap->type = IOMAP_DELALLOC;
118 } else {
119 xfs_daddr_t daddr = xfs_fsb_to_db(ip, imap->br_startblock);
120
121 iomap->addr = BBTOB(daddr);
122 if (mapping_flags & IOMAP_DAX)
123 iomap->addr += target->bt_dax_part_off;
124
125 if (imap->br_state == XFS_EXT_UNWRITTEN)
126 iomap->type = IOMAP_UNWRITTEN;
127 else
128 iomap->type = IOMAP_MAPPED;
129
130 /*
131 * Mark iomaps starting at the first sector of a RTG as merge
132 * boundary so that each I/O completions is contained to a
133 * single RTG.
134 */
135 if (XFS_IS_REALTIME_INODE(ip) && xfs_has_rtgroups(mp) &&
136 xfs_rtbno_is_group_start(mp, imap->br_startblock))
137 iomap->flags |= IOMAP_F_BOUNDARY;
138 }
139 iomap->offset = XFS_FSB_TO_B(mp, imap->br_startoff);
140 iomap->length = XFS_FSB_TO_B(mp, imap->br_blockcount);
141 if (mapping_flags & IOMAP_DAX)
142 iomap->dax_dev = target->bt_daxdev;
143 else
144 iomap->bdev = target->bt_bdev;
145 iomap->flags = iomap_flags;
146
147 if (xfs_ipincount(ip) &&
148 (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
149 iomap->flags |= IOMAP_F_DIRTY;
150
151 iomap->validity_cookie = sequence_cookie;
152 iomap->folio_ops = &xfs_iomap_folio_ops;
153 return 0;
154}
155
156static void
157xfs_hole_to_iomap(
158 struct xfs_inode *ip,
159 struct iomap *iomap,
160 xfs_fileoff_t offset_fsb,
161 xfs_fileoff_t end_fsb)
162{
163 struct xfs_buftarg *target = xfs_inode_buftarg(ip);
164
165 iomap->addr = IOMAP_NULL_ADDR;
166 iomap->type = IOMAP_HOLE;
167 iomap->offset = XFS_FSB_TO_B(ip->i_mount, offset_fsb);
168 iomap->length = XFS_FSB_TO_B(ip->i_mount, end_fsb - offset_fsb);
169 iomap->bdev = target->bt_bdev;
170 iomap->dax_dev = target->bt_daxdev;
171}
172
173static inline xfs_fileoff_t
174xfs_iomap_end_fsb(
175 struct xfs_mount *mp,
176 loff_t offset,
177 loff_t count)
178{
179 ASSERT(offset <= mp->m_super->s_maxbytes);
180 return min(XFS_B_TO_FSB(mp, offset + count),
181 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
182}
183
184static xfs_extlen_t
185xfs_eof_alignment(
186 struct xfs_inode *ip)
187{
188 struct xfs_mount *mp = ip->i_mount;
189 xfs_extlen_t align = 0;
190
191 if (!XFS_IS_REALTIME_INODE(ip)) {
192 /*
193 * Round up the allocation request to a stripe unit
194 * (m_dalign) boundary if the file size is >= stripe unit
195 * size, and we are allocating past the allocation eof.
196 *
197 * If mounted with the "-o swalloc" option the alignment is
198 * increased from the strip unit size to the stripe width.
199 */
200 if (mp->m_swidth && xfs_has_swalloc(mp))
201 align = mp->m_swidth;
202 else if (mp->m_dalign)
203 align = mp->m_dalign;
204
205 if (align && XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, align))
206 align = 0;
207 }
208
209 return align;
210}
211
212/*
213 * Check if last_fsb is outside the last extent, and if so grow it to the next
214 * stripe unit boundary.
215 */
216xfs_fileoff_t
217xfs_iomap_eof_align_last_fsb(
218 struct xfs_inode *ip,
219 xfs_fileoff_t end_fsb)
220{
221 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
222 xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
223 xfs_extlen_t align = xfs_eof_alignment(ip);
224 struct xfs_bmbt_irec irec;
225 struct xfs_iext_cursor icur;
226
227 ASSERT(!xfs_need_iread_extents(ifp));
228
229 /*
230 * Always round up the allocation request to the extent hint boundary.
231 */
232 if (extsz) {
233 if (align)
234 align = roundup_64(align, extsz);
235 else
236 align = extsz;
237 }
238
239 if (align) {
240 xfs_fileoff_t aligned_end_fsb = roundup_64(end_fsb, align);
241
242 xfs_iext_last(ifp, &icur);
243 if (!xfs_iext_get_extent(ifp, &icur, &irec) ||
244 aligned_end_fsb >= irec.br_startoff + irec.br_blockcount)
245 return aligned_end_fsb;
246 }
247
248 return end_fsb;
249}
250
251int
252xfs_iomap_write_direct(
253 struct xfs_inode *ip,
254 xfs_fileoff_t offset_fsb,
255 xfs_fileoff_t count_fsb,
256 unsigned int flags,
257 struct xfs_bmbt_irec *imap,
258 u64 *seq)
259{
260 struct xfs_mount *mp = ip->i_mount;
261 struct xfs_trans *tp;
262 xfs_filblks_t resaligned;
263 int nimaps;
264 unsigned int dblocks, rblocks;
265 bool force = false;
266 int error;
267 int bmapi_flags = XFS_BMAPI_PREALLOC;
268 int nr_exts = XFS_IEXT_ADD_NOSPLIT_CNT;
269
270 ASSERT(count_fsb > 0);
271
272 resaligned = xfs_aligned_fsb_count(offset_fsb, count_fsb,
273 xfs_get_extsz_hint(ip));
274 if (unlikely(XFS_IS_REALTIME_INODE(ip))) {
275 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
276 rblocks = resaligned;
277 } else {
278 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
279 rblocks = 0;
280 }
281
282 error = xfs_qm_dqattach(ip);
283 if (error)
284 return error;
285
286 /*
287 * For DAX, we do not allocate unwritten extents, but instead we zero
288 * the block before we commit the transaction. Ideally we'd like to do
289 * this outside the transaction context, but if we commit and then crash
290 * we may not have zeroed the blocks and this will be exposed on
291 * recovery of the allocation. Hence we must zero before commit.
292 *
293 * Further, if we are mapping unwritten extents here, we need to zero
294 * and convert them to written so that we don't need an unwritten extent
295 * callback for DAX. This also means that we need to be able to dip into
296 * the reserve block pool for bmbt block allocation if there is no space
297 * left but we need to do unwritten extent conversion.
298 */
299 if (flags & IOMAP_DAX) {
300 bmapi_flags = XFS_BMAPI_CONVERT | XFS_BMAPI_ZERO;
301 if (imap->br_state == XFS_EXT_UNWRITTEN) {
302 force = true;
303 nr_exts = XFS_IEXT_WRITE_UNWRITTEN_CNT;
304 dblocks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
305 }
306 }
307
308 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, dblocks,
309 rblocks, force, &tp);
310 if (error)
311 return error;
312
313 error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK, nr_exts);
314 if (error)
315 goto out_trans_cancel;
316
317 /*
318 * From this point onwards we overwrite the imap pointer that the
319 * caller gave to us.
320 */
321 nimaps = 1;
322 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb, bmapi_flags, 0,
323 imap, &nimaps);
324 if (error)
325 goto out_trans_cancel;
326
327 /*
328 * Complete the transaction
329 */
330 error = xfs_trans_commit(tp);
331 if (error)
332 goto out_unlock;
333
334 if (unlikely(!xfs_valid_startblock(ip, imap->br_startblock))) {
335 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
336 error = xfs_alert_fsblock_zero(ip, imap);
337 }
338
339out_unlock:
340 *seq = xfs_iomap_inode_sequence(ip, 0);
341 xfs_iunlock(ip, XFS_ILOCK_EXCL);
342 return error;
343
344out_trans_cancel:
345 xfs_trans_cancel(tp);
346 goto out_unlock;
347}
348
349STATIC bool
350xfs_quota_need_throttle(
351 struct xfs_inode *ip,
352 xfs_dqtype_t type,
353 xfs_fsblock_t alloc_blocks)
354{
355 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
356 struct xfs_dquot_res *res;
357 struct xfs_dquot_pre *pre;
358
359 if (!dq || !xfs_this_quota_on(ip->i_mount, type))
360 return false;
361
362 if (XFS_IS_REALTIME_INODE(ip)) {
363 res = &dq->q_rtb;
364 pre = &dq->q_rtb_prealloc;
365 } else {
366 res = &dq->q_blk;
367 pre = &dq->q_blk_prealloc;
368 }
369
370 /* no hi watermark, no throttle */
371 if (!pre->q_prealloc_hi_wmark)
372 return false;
373
374 /* under the lo watermark, no throttle */
375 if (res->reserved + alloc_blocks < pre->q_prealloc_lo_wmark)
376 return false;
377
378 return true;
379}
380
381STATIC void
382xfs_quota_calc_throttle(
383 struct xfs_inode *ip,
384 xfs_dqtype_t type,
385 xfs_fsblock_t *qblocks,
386 int *qshift,
387 int64_t *qfreesp)
388{
389 struct xfs_dquot *dq = xfs_inode_dquot(ip, type);
390 struct xfs_dquot_res *res;
391 struct xfs_dquot_pre *pre;
392 int64_t freesp;
393 int shift = 0;
394
395 if (!dq) {
396 res = NULL;
397 pre = NULL;
398 } else if (XFS_IS_REALTIME_INODE(ip)) {
399 res = &dq->q_rtb;
400 pre = &dq->q_rtb_prealloc;
401 } else {
402 res = &dq->q_blk;
403 pre = &dq->q_blk_prealloc;
404 }
405
406 /* no dq, or over hi wmark, squash the prealloc completely */
407 if (!res || res->reserved >= pre->q_prealloc_hi_wmark) {
408 *qblocks = 0;
409 *qfreesp = 0;
410 return;
411 }
412
413 freesp = pre->q_prealloc_hi_wmark - res->reserved;
414 if (freesp < pre->q_low_space[XFS_QLOWSP_5_PCNT]) {
415 shift = 2;
416 if (freesp < pre->q_low_space[XFS_QLOWSP_3_PCNT])
417 shift += 2;
418 if (freesp < pre->q_low_space[XFS_QLOWSP_1_PCNT])
419 shift += 2;
420 }
421
422 if (freesp < *qfreesp)
423 *qfreesp = freesp;
424
425 /* only overwrite the throttle values if we are more aggressive */
426 if ((freesp >> shift) < (*qblocks >> *qshift)) {
427 *qblocks = freesp;
428 *qshift = shift;
429 }
430}
431
432static int64_t
433xfs_iomap_freesp(
434 struct percpu_counter *counter,
435 uint64_t low_space[XFS_LOWSP_MAX],
436 int *shift)
437{
438 int64_t freesp;
439
440 freesp = percpu_counter_read_positive(counter);
441 if (freesp < low_space[XFS_LOWSP_5_PCNT]) {
442 *shift = 2;
443 if (freesp < low_space[XFS_LOWSP_4_PCNT])
444 (*shift)++;
445 if (freesp < low_space[XFS_LOWSP_3_PCNT])
446 (*shift)++;
447 if (freesp < low_space[XFS_LOWSP_2_PCNT])
448 (*shift)++;
449 if (freesp < low_space[XFS_LOWSP_1_PCNT])
450 (*shift)++;
451 }
452 return freesp;
453}
454
455/*
456 * If we don't have a user specified preallocation size, dynamically increase
457 * the preallocation size as the size of the file grows. Cap the maximum size
458 * at a single extent or less if the filesystem is near full. The closer the
459 * filesystem is to being full, the smaller the maximum preallocation.
460 */
461STATIC xfs_fsblock_t
462xfs_iomap_prealloc_size(
463 struct xfs_inode *ip,
464 int whichfork,
465 loff_t offset,
466 loff_t count,
467 struct xfs_iext_cursor *icur)
468{
469 struct xfs_iext_cursor ncur = *icur;
470 struct xfs_bmbt_irec prev, got;
471 struct xfs_mount *mp = ip->i_mount;
472 struct xfs_ifork *ifp = xfs_ifork_ptr(ip, whichfork);
473 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
474 int64_t freesp;
475 xfs_fsblock_t qblocks;
476 xfs_fsblock_t alloc_blocks = 0;
477 xfs_extlen_t plen;
478 int shift = 0;
479 int qshift = 0;
480
481 /*
482 * As an exception we don't do any preallocation at all if the file is
483 * smaller than the minimum preallocation and we are using the default
484 * dynamic preallocation scheme, as it is likely this is the only write
485 * to the file that is going to be done.
486 */
487 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_allocsize_blocks))
488 return 0;
489
490 /*
491 * Use the minimum preallocation size for small files or if we are
492 * writing right after a hole.
493 */
494 if (XFS_ISIZE(ip) < XFS_FSB_TO_B(mp, mp->m_dalign) ||
495 !xfs_iext_prev_extent(ifp, &ncur, &prev) ||
496 prev.br_startoff + prev.br_blockcount < offset_fsb)
497 return mp->m_allocsize_blocks;
498
499 /*
500 * Take the size of the preceding data extents as the basis for the
501 * preallocation size. Note that we don't care if the previous extents
502 * are written or not.
503 */
504 plen = prev.br_blockcount;
505 while (xfs_iext_prev_extent(ifp, &ncur, &got)) {
506 if (plen > XFS_MAX_BMBT_EXTLEN / 2 ||
507 isnullstartblock(got.br_startblock) ||
508 got.br_startoff + got.br_blockcount != prev.br_startoff ||
509 got.br_startblock + got.br_blockcount != prev.br_startblock)
510 break;
511 plen += got.br_blockcount;
512 prev = got;
513 }
514
515 /*
516 * If the size of the extents is greater than half the maximum extent
517 * length, then use the current offset as the basis. This ensures that
518 * for large files the preallocation size always extends to
519 * XFS_BMBT_MAX_EXTLEN rather than falling short due to things like stripe
520 * unit/width alignment of real extents.
521 */
522 alloc_blocks = plen * 2;
523 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
524 alloc_blocks = XFS_B_TO_FSB(mp, offset);
525 qblocks = alloc_blocks;
526
527 /*
528 * XFS_BMBT_MAX_EXTLEN is not a power of two value but we round the prealloc
529 * down to the nearest power of two value after throttling. To prevent
530 * the round down from unconditionally reducing the maximum supported
531 * prealloc size, we round up first, apply appropriate throttling, round
532 * down and cap the value to XFS_BMBT_MAX_EXTLEN.
533 */
534 alloc_blocks = XFS_FILEOFF_MIN(roundup_pow_of_two(XFS_MAX_BMBT_EXTLEN),
535 alloc_blocks);
536
537 if (unlikely(XFS_IS_REALTIME_INODE(ip)))
538 freesp = xfs_rtbxlen_to_blen(mp,
539 xfs_iomap_freesp(&mp->m_frextents,
540 mp->m_low_rtexts, &shift));
541 else
542 freesp = xfs_iomap_freesp(&mp->m_fdblocks, mp->m_low_space,
543 &shift);
544
545 /*
546 * Check each quota to cap the prealloc size, provide a shift value to
547 * throttle with and adjust amount of available space.
548 */
549 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_USER, alloc_blocks))
550 xfs_quota_calc_throttle(ip, XFS_DQTYPE_USER, &qblocks, &qshift,
551 &freesp);
552 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_GROUP, alloc_blocks))
553 xfs_quota_calc_throttle(ip, XFS_DQTYPE_GROUP, &qblocks, &qshift,
554 &freesp);
555 if (xfs_quota_need_throttle(ip, XFS_DQTYPE_PROJ, alloc_blocks))
556 xfs_quota_calc_throttle(ip, XFS_DQTYPE_PROJ, &qblocks, &qshift,
557 &freesp);
558
559 /*
560 * The final prealloc size is set to the minimum of free space available
561 * in each of the quotas and the overall filesystem.
562 *
563 * The shift throttle value is set to the maximum value as determined by
564 * the global low free space values and per-quota low free space values.
565 */
566 alloc_blocks = min(alloc_blocks, qblocks);
567 shift = max(shift, qshift);
568
569 if (shift)
570 alloc_blocks >>= shift;
571 /*
572 * rounddown_pow_of_two() returns an undefined result if we pass in
573 * alloc_blocks = 0.
574 */
575 if (alloc_blocks)
576 alloc_blocks = rounddown_pow_of_two(alloc_blocks);
577 if (alloc_blocks > XFS_MAX_BMBT_EXTLEN)
578 alloc_blocks = XFS_MAX_BMBT_EXTLEN;
579
580 /*
581 * If we are still trying to allocate more space than is
582 * available, squash the prealloc hard. This can happen if we
583 * have a large file on a small filesystem and the above
584 * lowspace thresholds are smaller than XFS_BMBT_MAX_EXTLEN.
585 */
586 while (alloc_blocks && alloc_blocks >= freesp)
587 alloc_blocks >>= 4;
588 if (alloc_blocks < mp->m_allocsize_blocks)
589 alloc_blocks = mp->m_allocsize_blocks;
590 trace_xfs_iomap_prealloc_size(ip, alloc_blocks, shift,
591 mp->m_allocsize_blocks);
592 return alloc_blocks;
593}
594
595int
596xfs_iomap_write_unwritten(
597 xfs_inode_t *ip,
598 xfs_off_t offset,
599 xfs_off_t count,
600 bool update_isize)
601{
602 xfs_mount_t *mp = ip->i_mount;
603 xfs_fileoff_t offset_fsb;
604 xfs_filblks_t count_fsb;
605 xfs_filblks_t numblks_fsb;
606 int nimaps;
607 xfs_trans_t *tp;
608 xfs_bmbt_irec_t imap;
609 struct inode *inode = VFS_I(ip);
610 xfs_fsize_t i_size;
611 uint resblks;
612 int error;
613
614 trace_xfs_unwritten_convert(ip, offset, count);
615
616 offset_fsb = XFS_B_TO_FSBT(mp, offset);
617 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
618 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
619
620 /*
621 * Reserve enough blocks in this transaction for two complete extent
622 * btree splits. We may be converting the middle part of an unwritten
623 * extent and in this case we will insert two new extents in the btree
624 * each of which could cause a full split.
625 *
626 * This reservation amount will be used in the first call to
627 * xfs_bmbt_split() to select an AG with enough space to satisfy the
628 * rest of the operation.
629 */
630 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
631
632 /* Attach dquots so that bmbt splits are accounted correctly. */
633 error = xfs_qm_dqattach(ip);
634 if (error)
635 return error;
636
637 do {
638 /*
639 * Set up a transaction to convert the range of extents
640 * from unwritten to real. Do allocations in a loop until
641 * we have covered the range passed in.
642 *
643 * Note that we can't risk to recursing back into the filesystem
644 * here as we might be asked to write out the same inode that we
645 * complete here and might deadlock on the iolock.
646 */
647 error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks,
648 0, true, &tp);
649 if (error)
650 return error;
651
652 error = xfs_iext_count_extend(tp, ip, XFS_DATA_FORK,
653 XFS_IEXT_WRITE_UNWRITTEN_CNT);
654 if (error)
655 goto error_on_bmapi_transaction;
656
657 /*
658 * Modify the unwritten extent state of the buffer.
659 */
660 nimaps = 1;
661 error = xfs_bmapi_write(tp, ip, offset_fsb, count_fsb,
662 XFS_BMAPI_CONVERT, resblks, &imap,
663 &nimaps);
664 if (error)
665 goto error_on_bmapi_transaction;
666
667 /*
668 * Log the updated inode size as we go. We have to be careful
669 * to only log it up to the actual write offset if it is
670 * halfway into a block.
671 */
672 i_size = XFS_FSB_TO_B(mp, offset_fsb + count_fsb);
673 if (i_size > offset + count)
674 i_size = offset + count;
675 if (update_isize && i_size > i_size_read(inode))
676 i_size_write(inode, i_size);
677 i_size = xfs_new_eof(ip, i_size);
678 if (i_size) {
679 ip->i_disk_size = i_size;
680 xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
681 }
682
683 error = xfs_trans_commit(tp);
684 xfs_iunlock(ip, XFS_ILOCK_EXCL);
685 if (error)
686 return error;
687
688 if (unlikely(!xfs_valid_startblock(ip, imap.br_startblock))) {
689 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
690 return xfs_alert_fsblock_zero(ip, &imap);
691 }
692
693 if ((numblks_fsb = imap.br_blockcount) == 0) {
694 /*
695 * The numblks_fsb value should always get
696 * smaller, otherwise the loop is stuck.
697 */
698 ASSERT(imap.br_blockcount);
699 break;
700 }
701 offset_fsb += numblks_fsb;
702 count_fsb -= numblks_fsb;
703 } while (count_fsb > 0);
704
705 return 0;
706
707error_on_bmapi_transaction:
708 xfs_trans_cancel(tp);
709 xfs_iunlock(ip, XFS_ILOCK_EXCL);
710 return error;
711}
712
713static inline bool
714imap_needs_alloc(
715 struct inode *inode,
716 unsigned flags,
717 struct xfs_bmbt_irec *imap,
718 int nimaps)
719{
720 /* don't allocate blocks when just zeroing */
721 if (flags & IOMAP_ZERO)
722 return false;
723 if (!nimaps ||
724 imap->br_startblock == HOLESTARTBLOCK ||
725 imap->br_startblock == DELAYSTARTBLOCK)
726 return true;
727 /* we convert unwritten extents before copying the data for DAX */
728 if ((flags & IOMAP_DAX) && imap->br_state == XFS_EXT_UNWRITTEN)
729 return true;
730 return false;
731}
732
733static inline bool
734imap_needs_cow(
735 struct xfs_inode *ip,
736 unsigned int flags,
737 struct xfs_bmbt_irec *imap,
738 int nimaps)
739{
740 if (!xfs_is_cow_inode(ip))
741 return false;
742
743 /* when zeroing we don't have to COW holes or unwritten extents */
744 if (flags & (IOMAP_UNSHARE | IOMAP_ZERO)) {
745 if (!nimaps ||
746 imap->br_startblock == HOLESTARTBLOCK ||
747 imap->br_state == XFS_EXT_UNWRITTEN)
748 return false;
749 }
750
751 return true;
752}
753
754/*
755 * Extents not yet cached requires exclusive access, don't block for
756 * IOMAP_NOWAIT.
757 *
758 * This is basically an opencoded xfs_ilock_data_map_shared() call, but with
759 * support for IOMAP_NOWAIT.
760 */
761static int
762xfs_ilock_for_iomap(
763 struct xfs_inode *ip,
764 unsigned flags,
765 unsigned *lockmode)
766{
767 if (flags & IOMAP_NOWAIT) {
768 if (xfs_need_iread_extents(&ip->i_df))
769 return -EAGAIN;
770 if (!xfs_ilock_nowait(ip, *lockmode))
771 return -EAGAIN;
772 } else {
773 if (xfs_need_iread_extents(&ip->i_df))
774 *lockmode = XFS_ILOCK_EXCL;
775 xfs_ilock(ip, *lockmode);
776 }
777
778 return 0;
779}
780
781/*
782 * Check that the imap we are going to return to the caller spans the entire
783 * range that the caller requested for the IO.
784 */
785static bool
786imap_spans_range(
787 struct xfs_bmbt_irec *imap,
788 xfs_fileoff_t offset_fsb,
789 xfs_fileoff_t end_fsb)
790{
791 if (imap->br_startoff > offset_fsb)
792 return false;
793 if (imap->br_startoff + imap->br_blockcount < end_fsb)
794 return false;
795 return true;
796}
797
798static int
799xfs_direct_write_iomap_begin(
800 struct inode *inode,
801 loff_t offset,
802 loff_t length,
803 unsigned flags,
804 struct iomap *iomap,
805 struct iomap *srcmap)
806{
807 struct xfs_inode *ip = XFS_I(inode);
808 struct xfs_mount *mp = ip->i_mount;
809 struct xfs_bmbt_irec imap, cmap;
810 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
811 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
812 int nimaps = 1, error = 0;
813 bool shared = false;
814 u16 iomap_flags = 0;
815 unsigned int lockmode;
816 u64 seq;
817
818 ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
819
820 if (xfs_is_shutdown(mp))
821 return -EIO;
822
823 /*
824 * Writes that span EOF might trigger an IO size update on completion,
825 * so consider them to be dirty for the purposes of O_DSYNC even if
826 * there is no other metadata changes pending or have been made here.
827 */
828 if (offset + length > i_size_read(inode))
829 iomap_flags |= IOMAP_F_DIRTY;
830
831 /*
832 * COW writes may allocate delalloc space or convert unwritten COW
833 * extents, so we need to make sure to take the lock exclusively here.
834 */
835 if (xfs_is_cow_inode(ip))
836 lockmode = XFS_ILOCK_EXCL;
837 else
838 lockmode = XFS_ILOCK_SHARED;
839
840relock:
841 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
842 if (error)
843 return error;
844
845 /*
846 * The reflink iflag could have changed since the earlier unlocked
847 * check, check if it again and relock if needed.
848 */
849 if (xfs_is_cow_inode(ip) && lockmode == XFS_ILOCK_SHARED) {
850 xfs_iunlock(ip, lockmode);
851 lockmode = XFS_ILOCK_EXCL;
852 goto relock;
853 }
854
855 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
856 &nimaps, 0);
857 if (error)
858 goto out_unlock;
859
860 if (imap_needs_cow(ip, flags, &imap, nimaps)) {
861 error = -EAGAIN;
862 if (flags & IOMAP_NOWAIT)
863 goto out_unlock;
864
865 /* may drop and re-acquire the ilock */
866 error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
867 &lockmode,
868 (flags & IOMAP_DIRECT) || IS_DAX(inode));
869 if (error)
870 goto out_unlock;
871 if (shared)
872 goto out_found_cow;
873 end_fsb = imap.br_startoff + imap.br_blockcount;
874 length = XFS_FSB_TO_B(mp, end_fsb) - offset;
875 }
876
877 if (imap_needs_alloc(inode, flags, &imap, nimaps))
878 goto allocate_blocks;
879
880 /*
881 * NOWAIT and OVERWRITE I/O needs to span the entire requested I/O with
882 * a single map so that we avoid partial IO failures due to the rest of
883 * the I/O range not covered by this map triggering an EAGAIN condition
884 * when it is subsequently mapped and aborting the I/O.
885 */
886 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY)) {
887 error = -EAGAIN;
888 if (!imap_spans_range(&imap, offset_fsb, end_fsb))
889 goto out_unlock;
890 }
891
892 /*
893 * For overwrite only I/O, we cannot convert unwritten extents without
894 * requiring sub-block zeroing. This can only be done under an
895 * exclusive IOLOCK, hence return -EAGAIN if this is not a written
896 * extent to tell the caller to try again.
897 */
898 if (flags & IOMAP_OVERWRITE_ONLY) {
899 error = -EAGAIN;
900 if (imap.br_state != XFS_EXT_NORM &&
901 ((offset | length) & mp->m_blockmask))
902 goto out_unlock;
903 }
904
905 seq = xfs_iomap_inode_sequence(ip, iomap_flags);
906 xfs_iunlock(ip, lockmode);
907 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
908 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
909
910allocate_blocks:
911 error = -EAGAIN;
912 if (flags & (IOMAP_NOWAIT | IOMAP_OVERWRITE_ONLY))
913 goto out_unlock;
914
915 /*
916 * We cap the maximum length we map to a sane size to keep the chunks
917 * of work done where somewhat symmetric with the work writeback does.
918 * This is a completely arbitrary number pulled out of thin air as a
919 * best guess for initial testing.
920 *
921 * Note that the values needs to be less than 32-bits wide until the
922 * lower level functions are updated.
923 */
924 length = min_t(loff_t, length, 1024 * PAGE_SIZE);
925 end_fsb = xfs_iomap_end_fsb(mp, offset, length);
926
927 if (offset + length > XFS_ISIZE(ip))
928 end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
929 else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
930 end_fsb = min(end_fsb, imap.br_startoff + imap.br_blockcount);
931 xfs_iunlock(ip, lockmode);
932
933 error = xfs_iomap_write_direct(ip, offset_fsb, end_fsb - offset_fsb,
934 flags, &imap, &seq);
935 if (error)
936 return error;
937
938 trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
939 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
940 iomap_flags | IOMAP_F_NEW, seq);
941
942out_found_cow:
943 length = XFS_FSB_TO_B(mp, cmap.br_startoff + cmap.br_blockcount);
944 trace_xfs_iomap_found(ip, offset, length - offset, XFS_COW_FORK, &cmap);
945 if (imap.br_startblock != HOLESTARTBLOCK) {
946 seq = xfs_iomap_inode_sequence(ip, 0);
947 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0, seq);
948 if (error)
949 goto out_unlock;
950 }
951 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
952 xfs_iunlock(ip, lockmode);
953 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, IOMAP_F_SHARED, seq);
954
955out_unlock:
956 if (lockmode)
957 xfs_iunlock(ip, lockmode);
958 return error;
959}
960
961const struct iomap_ops xfs_direct_write_iomap_ops = {
962 .iomap_begin = xfs_direct_write_iomap_begin,
963};
964
965static int
966xfs_dax_write_iomap_end(
967 struct inode *inode,
968 loff_t pos,
969 loff_t length,
970 ssize_t written,
971 unsigned flags,
972 struct iomap *iomap)
973{
974 struct xfs_inode *ip = XFS_I(inode);
975
976 if (!xfs_is_cow_inode(ip))
977 return 0;
978
979 if (!written)
980 return xfs_reflink_cancel_cow_range(ip, pos, length, true);
981
982 return xfs_reflink_end_cow(ip, pos, written);
983}
984
985const struct iomap_ops xfs_dax_write_iomap_ops = {
986 .iomap_begin = xfs_direct_write_iomap_begin,
987 .iomap_end = xfs_dax_write_iomap_end,
988};
989
990static int
991xfs_buffered_write_iomap_begin(
992 struct inode *inode,
993 loff_t offset,
994 loff_t count,
995 unsigned flags,
996 struct iomap *iomap,
997 struct iomap *srcmap)
998{
999 struct xfs_inode *ip = XFS_I(inode);
1000 struct xfs_mount *mp = ip->i_mount;
1001 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1002 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1003 struct xfs_bmbt_irec imap, cmap;
1004 struct xfs_iext_cursor icur, ccur;
1005 xfs_fsblock_t prealloc_blocks = 0;
1006 bool eof = false, cow_eof = false, shared = false;
1007 int allocfork = XFS_DATA_FORK;
1008 int error = 0;
1009 unsigned int lockmode = XFS_ILOCK_EXCL;
1010 unsigned int iomap_flags = 0;
1011 u64 seq;
1012
1013 if (xfs_is_shutdown(mp))
1014 return -EIO;
1015
1016 /* we can't use delayed allocations when using extent size hints */
1017 if (xfs_get_extsz_hint(ip))
1018 return xfs_direct_write_iomap_begin(inode, offset, count,
1019 flags, iomap, srcmap);
1020
1021 error = xfs_qm_dqattach(ip);
1022 if (error)
1023 return error;
1024
1025 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
1026 if (error)
1027 return error;
1028
1029 if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
1030 XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
1031 xfs_bmap_mark_sick(ip, XFS_DATA_FORK);
1032 error = -EFSCORRUPTED;
1033 goto out_unlock;
1034 }
1035
1036 XFS_STATS_INC(mp, xs_blk_mapw);
1037
1038 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1039 if (error)
1040 goto out_unlock;
1041
1042 /*
1043 * Search the data fork first to look up our source mapping. We
1044 * always need the data fork map, as we have to return it to the
1045 * iomap code so that the higher level write code can read data in to
1046 * perform read-modify-write cycles for unaligned writes.
1047 */
1048 eof = !xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap);
1049 if (eof)
1050 imap.br_startoff = end_fsb; /* fake hole until the end */
1051
1052 /* We never need to allocate blocks for zeroing or unsharing a hole. */
1053 if ((flags & (IOMAP_UNSHARE | IOMAP_ZERO)) &&
1054 imap.br_startoff > offset_fsb) {
1055 xfs_hole_to_iomap(ip, iomap, offset_fsb, imap.br_startoff);
1056 goto out_unlock;
1057 }
1058
1059 /*
1060 * For zeroing, trim a delalloc extent that extends beyond the EOF
1061 * block. If it starts beyond the EOF block, convert it to an
1062 * unwritten extent.
1063 */
1064 if ((flags & IOMAP_ZERO) && imap.br_startoff <= offset_fsb &&
1065 isnullstartblock(imap.br_startblock)) {
1066 xfs_fileoff_t eof_fsb = XFS_B_TO_FSB(mp, XFS_ISIZE(ip));
1067
1068 if (offset_fsb >= eof_fsb)
1069 goto convert_delay;
1070 if (end_fsb > eof_fsb) {
1071 end_fsb = eof_fsb;
1072 xfs_trim_extent(&imap, offset_fsb,
1073 end_fsb - offset_fsb);
1074 }
1075 }
1076
1077 /*
1078 * Search the COW fork extent list even if we did not find a data fork
1079 * extent. This serves two purposes: first this implements the
1080 * speculative preallocation using cowextsize, so that we also unshare
1081 * block adjacent to shared blocks instead of just the shared blocks
1082 * themselves. Second the lookup in the extent list is generally faster
1083 * than going out to the shared extent tree.
1084 */
1085 if (xfs_is_cow_inode(ip)) {
1086 if (!ip->i_cowfp) {
1087 ASSERT(!xfs_is_reflink_inode(ip));
1088 xfs_ifork_init_cow(ip);
1089 }
1090 cow_eof = !xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb,
1091 &ccur, &cmap);
1092 if (!cow_eof && cmap.br_startoff <= offset_fsb) {
1093 trace_xfs_reflink_cow_found(ip, &cmap);
1094 goto found_cow;
1095 }
1096 }
1097
1098 if (imap.br_startoff <= offset_fsb) {
1099 /*
1100 * For reflink files we may need a delalloc reservation when
1101 * overwriting shared extents. This includes zeroing of
1102 * existing extents that contain data.
1103 */
1104 if (!xfs_is_cow_inode(ip) ||
1105 ((flags & IOMAP_ZERO) && imap.br_state != XFS_EXT_NORM)) {
1106 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1107 &imap);
1108 goto found_imap;
1109 }
1110
1111 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1112
1113 /* Trim the mapping to the nearest shared extent boundary. */
1114 error = xfs_bmap_trim_cow(ip, &imap, &shared);
1115 if (error)
1116 goto out_unlock;
1117
1118 /* Not shared? Just report the (potentially capped) extent. */
1119 if (!shared) {
1120 trace_xfs_iomap_found(ip, offset, count, XFS_DATA_FORK,
1121 &imap);
1122 goto found_imap;
1123 }
1124
1125 /*
1126 * Fork all the shared blocks from our write offset until the
1127 * end of the extent.
1128 */
1129 allocfork = XFS_COW_FORK;
1130 end_fsb = imap.br_startoff + imap.br_blockcount;
1131 } else {
1132 /*
1133 * We cap the maximum length we map here to MAX_WRITEBACK_PAGES
1134 * pages to keep the chunks of work done where somewhat
1135 * symmetric with the work writeback does. This is a completely
1136 * arbitrary number pulled out of thin air.
1137 *
1138 * Note that the values needs to be less than 32-bits wide until
1139 * the lower level functions are updated.
1140 */
1141 count = min_t(loff_t, count, 1024 * PAGE_SIZE);
1142 end_fsb = xfs_iomap_end_fsb(mp, offset, count);
1143
1144 if (xfs_is_always_cow_inode(ip))
1145 allocfork = XFS_COW_FORK;
1146 }
1147
1148 if (eof && offset + count > XFS_ISIZE(ip)) {
1149 /*
1150 * Determine the initial size of the preallocation.
1151 * We clean up any extra preallocation when the file is closed.
1152 */
1153 if (xfs_has_allocsize(mp))
1154 prealloc_blocks = mp->m_allocsize_blocks;
1155 else if (allocfork == XFS_DATA_FORK)
1156 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1157 offset, count, &icur);
1158 else
1159 prealloc_blocks = xfs_iomap_prealloc_size(ip, allocfork,
1160 offset, count, &ccur);
1161 if (prealloc_blocks) {
1162 xfs_extlen_t align;
1163 xfs_off_t end_offset;
1164 xfs_fileoff_t p_end_fsb;
1165
1166 end_offset = XFS_ALLOC_ALIGN(mp, offset + count - 1);
1167 p_end_fsb = XFS_B_TO_FSBT(mp, end_offset) +
1168 prealloc_blocks;
1169
1170 align = xfs_eof_alignment(ip);
1171 if (align)
1172 p_end_fsb = roundup_64(p_end_fsb, align);
1173
1174 p_end_fsb = min(p_end_fsb,
1175 XFS_B_TO_FSB(mp, mp->m_super->s_maxbytes));
1176 ASSERT(p_end_fsb > offset_fsb);
1177 prealloc_blocks = p_end_fsb - end_fsb;
1178 }
1179 }
1180
1181 /*
1182 * Flag newly allocated delalloc blocks with IOMAP_F_NEW so we punch
1183 * them out if the write happens to fail.
1184 */
1185 iomap_flags |= IOMAP_F_NEW;
1186 if (allocfork == XFS_COW_FORK) {
1187 error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1188 end_fsb - offset_fsb, prealloc_blocks, &cmap,
1189 &ccur, cow_eof);
1190 if (error)
1191 goto out_unlock;
1192
1193 trace_xfs_iomap_alloc(ip, offset, count, allocfork, &cmap);
1194 goto found_cow;
1195 }
1196
1197 error = xfs_bmapi_reserve_delalloc(ip, allocfork, offset_fsb,
1198 end_fsb - offset_fsb, prealloc_blocks, &imap, &icur,
1199 eof);
1200 if (error)
1201 goto out_unlock;
1202
1203 trace_xfs_iomap_alloc(ip, offset, count, allocfork, &imap);
1204found_imap:
1205 seq = xfs_iomap_inode_sequence(ip, iomap_flags);
1206 xfs_iunlock(ip, lockmode);
1207 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, iomap_flags, seq);
1208
1209convert_delay:
1210 xfs_iunlock(ip, lockmode);
1211 truncate_pagecache(inode, offset);
1212 error = xfs_bmapi_convert_delalloc(ip, XFS_DATA_FORK, offset,
1213 iomap, NULL);
1214 if (error)
1215 return error;
1216
1217 trace_xfs_iomap_alloc(ip, offset, count, XFS_DATA_FORK, &imap);
1218 return 0;
1219
1220found_cow:
1221 if (imap.br_startoff <= offset_fsb) {
1222 error = xfs_bmbt_to_iomap(ip, srcmap, &imap, flags, 0,
1223 xfs_iomap_inode_sequence(ip, 0));
1224 if (error)
1225 goto out_unlock;
1226 } else {
1227 xfs_trim_extent(&cmap, offset_fsb,
1228 imap.br_startoff - offset_fsb);
1229 }
1230
1231 iomap_flags |= IOMAP_F_SHARED;
1232 seq = xfs_iomap_inode_sequence(ip, iomap_flags);
1233 xfs_iunlock(ip, lockmode);
1234 return xfs_bmbt_to_iomap(ip, iomap, &cmap, flags, iomap_flags, seq);
1235
1236out_unlock:
1237 xfs_iunlock(ip, lockmode);
1238 return error;
1239}
1240
1241static void
1242xfs_buffered_write_delalloc_punch(
1243 struct inode *inode,
1244 loff_t offset,
1245 loff_t length,
1246 struct iomap *iomap)
1247{
1248 xfs_bmap_punch_delalloc_range(XFS_I(inode),
1249 (iomap->flags & IOMAP_F_SHARED) ?
1250 XFS_COW_FORK : XFS_DATA_FORK,
1251 offset, offset + length);
1252}
1253
1254static int
1255xfs_buffered_write_iomap_end(
1256 struct inode *inode,
1257 loff_t offset,
1258 loff_t length,
1259 ssize_t written,
1260 unsigned flags,
1261 struct iomap *iomap)
1262{
1263 loff_t start_byte, end_byte;
1264
1265 /* If we didn't reserve the blocks, we're not allowed to punch them. */
1266 if (iomap->type != IOMAP_DELALLOC || !(iomap->flags & IOMAP_F_NEW))
1267 return 0;
1268
1269 /*
1270 * iomap_page_mkwrite() will never fail in a way that requires delalloc
1271 * extents that it allocated to be revoked. Hence never try to release
1272 * them here.
1273 */
1274 if (flags & IOMAP_FAULT)
1275 return 0;
1276
1277 /* Nothing to do if we've written the entire delalloc extent */
1278 start_byte = iomap_last_written_block(inode, offset, written);
1279 end_byte = round_up(offset + length, i_blocksize(inode));
1280 if (start_byte >= end_byte)
1281 return 0;
1282
1283 /* For zeroing operations the callers already hold invalidate_lock. */
1284 if (flags & (IOMAP_UNSHARE | IOMAP_ZERO)) {
1285 rwsem_assert_held_write(&inode->i_mapping->invalidate_lock);
1286 iomap_write_delalloc_release(inode, start_byte, end_byte, flags,
1287 iomap, xfs_buffered_write_delalloc_punch);
1288 } else {
1289 filemap_invalidate_lock(inode->i_mapping);
1290 iomap_write_delalloc_release(inode, start_byte, end_byte, flags,
1291 iomap, xfs_buffered_write_delalloc_punch);
1292 filemap_invalidate_unlock(inode->i_mapping);
1293 }
1294
1295 return 0;
1296}
1297
1298const struct iomap_ops xfs_buffered_write_iomap_ops = {
1299 .iomap_begin = xfs_buffered_write_iomap_begin,
1300 .iomap_end = xfs_buffered_write_iomap_end,
1301};
1302
1303static int
1304xfs_read_iomap_begin(
1305 struct inode *inode,
1306 loff_t offset,
1307 loff_t length,
1308 unsigned flags,
1309 struct iomap *iomap,
1310 struct iomap *srcmap)
1311{
1312 struct xfs_inode *ip = XFS_I(inode);
1313 struct xfs_mount *mp = ip->i_mount;
1314 struct xfs_bmbt_irec imap;
1315 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1316 xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
1317 int nimaps = 1, error = 0;
1318 bool shared = false;
1319 unsigned int lockmode = XFS_ILOCK_SHARED;
1320 u64 seq;
1321
1322 ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));
1323
1324 if (xfs_is_shutdown(mp))
1325 return -EIO;
1326
1327 error = xfs_ilock_for_iomap(ip, flags, &lockmode);
1328 if (error)
1329 return error;
1330 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1331 &nimaps, 0);
1332 if (!error && ((flags & IOMAP_REPORT) || IS_DAX(inode)))
1333 error = xfs_reflink_trim_around_shared(ip, &imap, &shared);
1334 seq = xfs_iomap_inode_sequence(ip, shared ? IOMAP_F_SHARED : 0);
1335 xfs_iunlock(ip, lockmode);
1336
1337 if (error)
1338 return error;
1339 trace_xfs_iomap_found(ip, offset, length, XFS_DATA_FORK, &imap);
1340 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags,
1341 shared ? IOMAP_F_SHARED : 0, seq);
1342}
1343
1344const struct iomap_ops xfs_read_iomap_ops = {
1345 .iomap_begin = xfs_read_iomap_begin,
1346};
1347
1348static int
1349xfs_seek_iomap_begin(
1350 struct inode *inode,
1351 loff_t offset,
1352 loff_t length,
1353 unsigned flags,
1354 struct iomap *iomap,
1355 struct iomap *srcmap)
1356{
1357 struct xfs_inode *ip = XFS_I(inode);
1358 struct xfs_mount *mp = ip->i_mount;
1359 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1360 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1361 xfs_fileoff_t cow_fsb = NULLFILEOFF, data_fsb = NULLFILEOFF;
1362 struct xfs_iext_cursor icur;
1363 struct xfs_bmbt_irec imap, cmap;
1364 int error = 0;
1365 unsigned lockmode;
1366 u64 seq;
1367
1368 if (xfs_is_shutdown(mp))
1369 return -EIO;
1370
1371 lockmode = xfs_ilock_data_map_shared(ip);
1372 error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
1373 if (error)
1374 goto out_unlock;
1375
1376 if (xfs_iext_lookup_extent(ip, &ip->i_df, offset_fsb, &icur, &imap)) {
1377 /*
1378 * If we found a data extent we are done.
1379 */
1380 if (imap.br_startoff <= offset_fsb)
1381 goto done;
1382 data_fsb = imap.br_startoff;
1383 } else {
1384 /*
1385 * Fake a hole until the end of the file.
1386 */
1387 data_fsb = xfs_iomap_end_fsb(mp, offset, length);
1388 }
1389
1390 /*
1391 * If a COW fork extent covers the hole, report it - capped to the next
1392 * data fork extent:
1393 */
1394 if (xfs_inode_has_cow_data(ip) &&
1395 xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &cmap))
1396 cow_fsb = cmap.br_startoff;
1397 if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
1398 if (data_fsb < cow_fsb + cmap.br_blockcount)
1399 end_fsb = min(end_fsb, data_fsb);
1400 xfs_trim_extent(&cmap, offset_fsb, end_fsb - offset_fsb);
1401 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_SHARED);
1402 error = xfs_bmbt_to_iomap(ip, iomap, &cmap, flags,
1403 IOMAP_F_SHARED, seq);
1404 /*
1405 * This is a COW extent, so we must probe the page cache
1406 * because there could be dirty page cache being backed
1407 * by this extent.
1408 */
1409 iomap->type = IOMAP_UNWRITTEN;
1410 goto out_unlock;
1411 }
1412
1413 /*
1414 * Else report a hole, capped to the next found data or COW extent.
1415 */
1416 if (cow_fsb != NULLFILEOFF && cow_fsb < data_fsb)
1417 imap.br_blockcount = cow_fsb - offset_fsb;
1418 else
1419 imap.br_blockcount = data_fsb - offset_fsb;
1420 imap.br_startoff = offset_fsb;
1421 imap.br_startblock = HOLESTARTBLOCK;
1422 imap.br_state = XFS_EXT_NORM;
1423done:
1424 seq = xfs_iomap_inode_sequence(ip, 0);
1425 xfs_trim_extent(&imap, offset_fsb, end_fsb - offset_fsb);
1426 error = xfs_bmbt_to_iomap(ip, iomap, &imap, flags, 0, seq);
1427out_unlock:
1428 xfs_iunlock(ip, lockmode);
1429 return error;
1430}
1431
1432const struct iomap_ops xfs_seek_iomap_ops = {
1433 .iomap_begin = xfs_seek_iomap_begin,
1434};
1435
1436static int
1437xfs_xattr_iomap_begin(
1438 struct inode *inode,
1439 loff_t offset,
1440 loff_t length,
1441 unsigned flags,
1442 struct iomap *iomap,
1443 struct iomap *srcmap)
1444{
1445 struct xfs_inode *ip = XFS_I(inode);
1446 struct xfs_mount *mp = ip->i_mount;
1447 xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
1448 xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + length);
1449 struct xfs_bmbt_irec imap;
1450 int nimaps = 1, error = 0;
1451 unsigned lockmode;
1452 int seq;
1453
1454 if (xfs_is_shutdown(mp))
1455 return -EIO;
1456
1457 lockmode = xfs_ilock_attr_map_shared(ip);
1458
1459 /* if there are no attribute fork or extents, return ENOENT */
1460 if (!xfs_inode_has_attr_fork(ip) || !ip->i_af.if_nextents) {
1461 error = -ENOENT;
1462 goto out_unlock;
1463 }
1464
1465 ASSERT(ip->i_af.if_format != XFS_DINODE_FMT_LOCAL);
1466 error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
1467 &nimaps, XFS_BMAPI_ATTRFORK);
1468out_unlock:
1469
1470 seq = xfs_iomap_inode_sequence(ip, IOMAP_F_XATTR);
1471 xfs_iunlock(ip, lockmode);
1472
1473 if (error)
1474 return error;
1475 ASSERT(nimaps);
1476 return xfs_bmbt_to_iomap(ip, iomap, &imap, flags, IOMAP_F_XATTR, seq);
1477}
1478
1479const struct iomap_ops xfs_xattr_iomap_ops = {
1480 .iomap_begin = xfs_xattr_iomap_begin,
1481};
1482
1483int
1484xfs_zero_range(
1485 struct xfs_inode *ip,
1486 loff_t pos,
1487 loff_t len,
1488 bool *did_zero)
1489{
1490 struct inode *inode = VFS_I(ip);
1491
1492 xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL);
1493
1494 if (IS_DAX(inode))
1495 return dax_zero_range(inode, pos, len, did_zero,
1496 &xfs_dax_write_iomap_ops);
1497 return iomap_zero_range(inode, pos, len, did_zero,
1498 &xfs_buffered_write_iomap_ops);
1499}
1500
1501int
1502xfs_truncate_page(
1503 struct xfs_inode *ip,
1504 loff_t pos,
1505 bool *did_zero)
1506{
1507 struct inode *inode = VFS_I(ip);
1508
1509 if (IS_DAX(inode))
1510 return dax_truncate_page(inode, pos, did_zero,
1511 &xfs_dax_write_iomap_ops);
1512 return iomap_truncate_page(inode, pos, did_zero,
1513 &xfs_buffered_write_iomap_ops);
1514}