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_bit.h"
21 #include "xfs_log.h"
22 #include "xfs_inum.h"
23 #include "xfs_trans.h"
24 #include "xfs_sb.h"
25 #include "xfs_ag.h"
26 #include "xfs_alloc.h"
27 #include "xfs_quota.h"
28 #include "xfs_mount.h"
29 #include "xfs_bmap_btree.h"
30 #include "xfs_alloc_btree.h"
31 #include "xfs_ialloc_btree.h"
32 #include "xfs_dinode.h"
33 #include "xfs_inode.h"
34 #include "xfs_btree.h"
35 #include "xfs_bmap.h"
36 #include "xfs_rtalloc.h"
37 #include "xfs_error.h"
38 #include "xfs_itable.h"
39 #include "xfs_rw.h"
40 #include "xfs_attr.h"
41 #include "xfs_buf_item.h"
42 #include "xfs_trans_space.h"
43 #include "xfs_utils.h"
44 #include "xfs_iomap.h"
45 #include "xfs_trace.h"
46
47
48 #define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \
49 << mp->m_writeio_log)
50 #define XFS_WRITE_IMAPS XFS_BMAP_MAX_NMAP
51
52 STATIC int
xfs_iomap_eof_align_last_fsb(xfs_mount_t * mp,xfs_inode_t * ip,xfs_extlen_t extsize,xfs_fileoff_t * last_fsb)53 xfs_iomap_eof_align_last_fsb(
54 xfs_mount_t *mp,
55 xfs_inode_t *ip,
56 xfs_extlen_t extsize,
57 xfs_fileoff_t *last_fsb)
58 {
59 xfs_fileoff_t new_last_fsb = 0;
60 xfs_extlen_t align;
61 int eof, error;
62
63 if (XFS_IS_REALTIME_INODE(ip))
64 ;
65 /*
66 * If mounted with the "-o swalloc" option, roundup the allocation
67 * request to a stripe width boundary if the file size is >=
68 * stripe width and we are allocating past the allocation eof.
69 */
70 else if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC) &&
71 (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_swidth)))
72 new_last_fsb = roundup_64(*last_fsb, mp->m_swidth);
73 /*
74 * Roundup the allocation request to a stripe unit (m_dalign) boundary
75 * if the file size is >= stripe unit size, and we are allocating past
76 * the allocation eof.
77 */
78 else if (mp->m_dalign && (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_dalign)))
79 new_last_fsb = roundup_64(*last_fsb, mp->m_dalign);
80
81 /*
82 * Always round up the allocation request to an extent boundary
83 * (when file on a real-time subvolume or has di_extsize hint).
84 */
85 if (extsize) {
86 if (new_last_fsb)
87 align = roundup_64(new_last_fsb, extsize);
88 else
89 align = extsize;
90 new_last_fsb = roundup_64(*last_fsb, align);
91 }
92
93 if (new_last_fsb) {
94 error = xfs_bmap_eof(ip, new_last_fsb, XFS_DATA_FORK, &eof);
95 if (error)
96 return error;
97 if (eof)
98 *last_fsb = new_last_fsb;
99 }
100 return 0;
101 }
102
103 STATIC int
xfs_alert_fsblock_zero(xfs_inode_t * ip,xfs_bmbt_irec_t * imap)104 xfs_alert_fsblock_zero(
105 xfs_inode_t *ip,
106 xfs_bmbt_irec_t *imap)
107 {
108 xfs_alert_tag(ip->i_mount, XFS_PTAG_FSBLOCK_ZERO,
109 "Access to block zero in inode %llu "
110 "start_block: %llx start_off: %llx "
111 "blkcnt: %llx extent-state: %x\n",
112 (unsigned long long)ip->i_ino,
113 (unsigned long long)imap->br_startblock,
114 (unsigned long long)imap->br_startoff,
115 (unsigned long long)imap->br_blockcount,
116 imap->br_state);
117 return EFSCORRUPTED;
118 }
119
120 int
xfs_iomap_write_direct(xfs_inode_t * ip,xfs_off_t offset,size_t count,xfs_bmbt_irec_t * imap,int nmaps)121 xfs_iomap_write_direct(
122 xfs_inode_t *ip,
123 xfs_off_t offset,
124 size_t count,
125 xfs_bmbt_irec_t *imap,
126 int nmaps)
127 {
128 xfs_mount_t *mp = ip->i_mount;
129 xfs_fileoff_t offset_fsb;
130 xfs_fileoff_t last_fsb;
131 xfs_filblks_t count_fsb, resaligned;
132 xfs_fsblock_t firstfsb;
133 xfs_extlen_t extsz, temp;
134 int nimaps;
135 int bmapi_flag;
136 int quota_flag;
137 int rt;
138 xfs_trans_t *tp;
139 xfs_bmap_free_t free_list;
140 uint qblocks, resblks, resrtextents;
141 int committed;
142 int error;
143
144 /*
145 * Make sure that the dquots are there. This doesn't hold
146 * the ilock across a disk read.
147 */
148 error = xfs_qm_dqattach_locked(ip, 0);
149 if (error)
150 return XFS_ERROR(error);
151
152 rt = XFS_IS_REALTIME_INODE(ip);
153 extsz = xfs_get_extsz_hint(ip);
154
155 offset_fsb = XFS_B_TO_FSBT(mp, offset);
156 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
157 if ((offset + count) > ip->i_size) {
158 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
159 if (error)
160 goto error_out;
161 } else {
162 if (nmaps && (imap->br_startblock == HOLESTARTBLOCK))
163 last_fsb = MIN(last_fsb, (xfs_fileoff_t)
164 imap->br_blockcount +
165 imap->br_startoff);
166 }
167 count_fsb = last_fsb - offset_fsb;
168 ASSERT(count_fsb > 0);
169
170 resaligned = count_fsb;
171 if (unlikely(extsz)) {
172 if ((temp = do_mod(offset_fsb, extsz)))
173 resaligned += temp;
174 if ((temp = do_mod(resaligned, extsz)))
175 resaligned += extsz - temp;
176 }
177
178 if (unlikely(rt)) {
179 resrtextents = qblocks = resaligned;
180 resrtextents /= mp->m_sb.sb_rextsize;
181 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0);
182 quota_flag = XFS_QMOPT_RES_RTBLKS;
183 } else {
184 resrtextents = 0;
185 resblks = qblocks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned);
186 quota_flag = XFS_QMOPT_RES_REGBLKS;
187 }
188
189 /*
190 * Allocate and setup the transaction
191 */
192 xfs_iunlock(ip, XFS_ILOCK_EXCL);
193 tp = xfs_trans_alloc(mp, XFS_TRANS_DIOSTRAT);
194 error = xfs_trans_reserve(tp, resblks,
195 XFS_WRITE_LOG_RES(mp), resrtextents,
196 XFS_TRANS_PERM_LOG_RES,
197 XFS_WRITE_LOG_COUNT);
198 /*
199 * Check for running out of space, note: need lock to return
200 */
201 if (error)
202 xfs_trans_cancel(tp, 0);
203 xfs_ilock(ip, XFS_ILOCK_EXCL);
204 if (error)
205 goto error_out;
206
207 error = xfs_trans_reserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
208 if (error)
209 goto error1;
210
211 xfs_trans_ijoin(tp, ip);
212
213 bmapi_flag = XFS_BMAPI_WRITE;
214 if (offset < ip->i_size || extsz)
215 bmapi_flag |= XFS_BMAPI_PREALLOC;
216
217 /*
218 * Issue the xfs_bmapi() call to allocate the blocks.
219 *
220 * From this point onwards we overwrite the imap pointer that the
221 * caller gave to us.
222 */
223 xfs_bmap_init(&free_list, &firstfsb);
224 nimaps = 1;
225 error = xfs_bmapi(tp, ip, offset_fsb, count_fsb, bmapi_flag,
226 &firstfsb, 0, imap, &nimaps, &free_list);
227 if (error)
228 goto error0;
229
230 /*
231 * Complete the transaction
232 */
233 error = xfs_bmap_finish(&tp, &free_list, &committed);
234 if (error)
235 goto error0;
236 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
237 if (error)
238 goto error_out;
239
240 /*
241 * Copy any maps to caller's array and return any error.
242 */
243 if (nimaps == 0) {
244 error = ENOSPC;
245 goto error_out;
246 }
247
248 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip))) {
249 error = xfs_alert_fsblock_zero(ip, imap);
250 goto error_out;
251 }
252
253 return 0;
254
255 error0: /* Cancel bmap, unlock inode, unreserve quota blocks, cancel trans */
256 xfs_bmap_cancel(&free_list);
257 xfs_trans_unreserve_quota_nblks(tp, ip, qblocks, 0, quota_flag);
258
259 error1: /* Just cancel transaction */
260 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
261
262 error_out:
263 return XFS_ERROR(error);
264 }
265
266 /*
267 * If the caller is doing a write at the end of the file, then extend the
268 * allocation out to the file system's write iosize. We clean up any extra
269 * space left over when the file is closed in xfs_inactive().
270 *
271 * If we find we already have delalloc preallocation beyond EOF, don't do more
272 * preallocation as it it not needed.
273 */
274 STATIC int
xfs_iomap_eof_want_preallocate(xfs_mount_t * mp,xfs_inode_t * ip,xfs_off_t offset,size_t count,xfs_bmbt_irec_t * imap,int nimaps,int * prealloc)275 xfs_iomap_eof_want_preallocate(
276 xfs_mount_t *mp,
277 xfs_inode_t *ip,
278 xfs_off_t offset,
279 size_t count,
280 xfs_bmbt_irec_t *imap,
281 int nimaps,
282 int *prealloc)
283 {
284 xfs_fileoff_t start_fsb;
285 xfs_filblks_t count_fsb;
286 xfs_fsblock_t firstblock;
287 int n, error, imaps;
288 int found_delalloc = 0;
289
290 *prealloc = 0;
291 if ((offset + count) <= ip->i_size)
292 return 0;
293
294 /*
295 * If there are any real blocks past eof, then don't
296 * do any speculative allocation.
297 */
298 start_fsb = XFS_B_TO_FSBT(mp, ((xfs_ufsize_t)(offset + count - 1)));
299 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)XFS_MAXIOFFSET(mp));
300 while (count_fsb > 0) {
301 imaps = nimaps;
302 firstblock = NULLFSBLOCK;
303 error = xfs_bmapi(NULL, ip, start_fsb, count_fsb, 0,
304 &firstblock, 0, imap, &imaps, NULL);
305 if (error)
306 return error;
307 for (n = 0; n < imaps; n++) {
308 if ((imap[n].br_startblock != HOLESTARTBLOCK) &&
309 (imap[n].br_startblock != DELAYSTARTBLOCK))
310 return 0;
311 start_fsb += imap[n].br_blockcount;
312 count_fsb -= imap[n].br_blockcount;
313
314 if (imap[n].br_startblock == DELAYSTARTBLOCK)
315 found_delalloc = 1;
316 }
317 }
318 if (!found_delalloc)
319 *prealloc = 1;
320 return 0;
321 }
322
323 /*
324 * If we don't have a user specified preallocation size, dynamically increase
325 * the preallocation size as the size of the file grows. Cap the maximum size
326 * at a single extent or less if the filesystem is near full. The closer the
327 * filesystem is to full, the smaller the maximum prealocation.
328 */
329 STATIC xfs_fsblock_t
xfs_iomap_prealloc_size(struct xfs_mount * mp,struct xfs_inode * ip)330 xfs_iomap_prealloc_size(
331 struct xfs_mount *mp,
332 struct xfs_inode *ip)
333 {
334 xfs_fsblock_t alloc_blocks = 0;
335
336 if (!(mp->m_flags & XFS_MOUNT_DFLT_IOSIZE)) {
337 int shift = 0;
338 int64_t freesp;
339
340 /*
341 * rounddown_pow_of_two() returns an undefined result
342 * if we pass in alloc_blocks = 0. Hence the "+ 1" to
343 * ensure we always pass in a non-zero value.
344 */
345 alloc_blocks = XFS_B_TO_FSB(mp, ip->i_size) + 1;
346 alloc_blocks = XFS_FILEOFF_MIN(MAXEXTLEN,
347 rounddown_pow_of_two(alloc_blocks));
348
349 xfs_icsb_sync_counters(mp, XFS_ICSB_LAZY_COUNT);
350 freesp = mp->m_sb.sb_fdblocks;
351 if (freesp < mp->m_low_space[XFS_LOWSP_5_PCNT]) {
352 shift = 2;
353 if (freesp < mp->m_low_space[XFS_LOWSP_4_PCNT])
354 shift++;
355 if (freesp < mp->m_low_space[XFS_LOWSP_3_PCNT])
356 shift++;
357 if (freesp < mp->m_low_space[XFS_LOWSP_2_PCNT])
358 shift++;
359 if (freesp < mp->m_low_space[XFS_LOWSP_1_PCNT])
360 shift++;
361 }
362 if (shift)
363 alloc_blocks >>= shift;
364 }
365
366 if (alloc_blocks < mp->m_writeio_blocks)
367 alloc_blocks = mp->m_writeio_blocks;
368
369 return alloc_blocks;
370 }
371
372 int
xfs_iomap_write_delay(xfs_inode_t * ip,xfs_off_t offset,size_t count,xfs_bmbt_irec_t * ret_imap)373 xfs_iomap_write_delay(
374 xfs_inode_t *ip,
375 xfs_off_t offset,
376 size_t count,
377 xfs_bmbt_irec_t *ret_imap)
378 {
379 xfs_mount_t *mp = ip->i_mount;
380 xfs_fileoff_t offset_fsb;
381 xfs_fileoff_t last_fsb;
382 xfs_off_t aligned_offset;
383 xfs_fileoff_t ioalign;
384 xfs_fsblock_t firstblock;
385 xfs_extlen_t extsz;
386 int nimaps;
387 xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
388 int prealloc, flushed = 0;
389 int error;
390
391 ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
392
393 /*
394 * Make sure that the dquots are there. This doesn't hold
395 * the ilock across a disk read.
396 */
397 error = xfs_qm_dqattach_locked(ip, 0);
398 if (error)
399 return XFS_ERROR(error);
400
401 extsz = xfs_get_extsz_hint(ip);
402 offset_fsb = XFS_B_TO_FSBT(mp, offset);
403
404
405 error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count,
406 imap, XFS_WRITE_IMAPS, &prealloc);
407 if (error)
408 return error;
409
410 retry:
411 if (prealloc) {
412 xfs_fsblock_t alloc_blocks = xfs_iomap_prealloc_size(mp, ip);
413
414 aligned_offset = XFS_WRITEIO_ALIGN(mp, (offset + count - 1));
415 ioalign = XFS_B_TO_FSBT(mp, aligned_offset);
416 last_fsb = ioalign + alloc_blocks;
417 } else {
418 last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));
419 }
420
421 if (prealloc || extsz) {
422 error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);
423 if (error)
424 return error;
425 }
426
427 nimaps = XFS_WRITE_IMAPS;
428 firstblock = NULLFSBLOCK;
429 error = xfs_bmapi(NULL, ip, offset_fsb,
430 (xfs_filblks_t)(last_fsb - offset_fsb),
431 XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
432 XFS_BMAPI_ENTIRE, &firstblock, 1, imap,
433 &nimaps, NULL);
434 switch (error) {
435 case 0:
436 case ENOSPC:
437 case EDQUOT:
438 break;
439 default:
440 return XFS_ERROR(error);
441 }
442
443 /*
444 * If bmapi returned us nothing, we got either ENOSPC or EDQUOT. For
445 * ENOSPC, * flush all other inodes with delalloc blocks to free up
446 * some of the excess reserved metadata space. For both cases, retry
447 * without EOF preallocation.
448 */
449 if (nimaps == 0) {
450 trace_xfs_delalloc_enospc(ip, offset, count);
451 if (flushed)
452 return XFS_ERROR(error ? error : ENOSPC);
453
454 if (error == ENOSPC) {
455 xfs_iunlock(ip, XFS_ILOCK_EXCL);
456 xfs_flush_inodes(ip);
457 xfs_ilock(ip, XFS_ILOCK_EXCL);
458 }
459
460 flushed = 1;
461 error = 0;
462 prealloc = 0;
463 goto retry;
464 }
465
466 if (!(imap[0].br_startblock || XFS_IS_REALTIME_INODE(ip)))
467 return xfs_alert_fsblock_zero(ip, &imap[0]);
468
469 *ret_imap = imap[0];
470 return 0;
471 }
472
473 /*
474 * Pass in a delayed allocate extent, convert it to real extents;
475 * return to the caller the extent we create which maps on top of
476 * the originating callers request.
477 *
478 * Called without a lock on the inode.
479 *
480 * We no longer bother to look at the incoming map - all we have to
481 * guarantee is that whatever we allocate fills the required range.
482 */
483 int
xfs_iomap_write_allocate(xfs_inode_t * ip,xfs_off_t offset,size_t count,xfs_bmbt_irec_t * imap)484 xfs_iomap_write_allocate(
485 xfs_inode_t *ip,
486 xfs_off_t offset,
487 size_t count,
488 xfs_bmbt_irec_t *imap)
489 {
490 xfs_mount_t *mp = ip->i_mount;
491 xfs_fileoff_t offset_fsb, last_block;
492 xfs_fileoff_t end_fsb, map_start_fsb;
493 xfs_fsblock_t first_block;
494 xfs_bmap_free_t free_list;
495 xfs_filblks_t count_fsb;
496 xfs_trans_t *tp;
497 int nimaps, committed;
498 int error = 0;
499 int nres;
500
501 /*
502 * Make sure that the dquots are there.
503 */
504 error = xfs_qm_dqattach(ip, 0);
505 if (error)
506 return XFS_ERROR(error);
507
508 offset_fsb = XFS_B_TO_FSBT(mp, offset);
509 count_fsb = imap->br_blockcount;
510 map_start_fsb = imap->br_startoff;
511
512 XFS_STATS_ADD(xs_xstrat_bytes, XFS_FSB_TO_B(mp, count_fsb));
513
514 while (count_fsb != 0) {
515 /*
516 * Set up a transaction with which to allocate the
517 * backing store for the file. Do allocations in a
518 * loop until we get some space in the range we are
519 * interested in. The other space that might be allocated
520 * is in the delayed allocation extent on which we sit
521 * but before our buffer starts.
522 */
523
524 nimaps = 0;
525 while (nimaps == 0) {
526 tp = xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE);
527 tp->t_flags |= XFS_TRANS_RESERVE;
528 nres = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK);
529 error = xfs_trans_reserve(tp, nres,
530 XFS_WRITE_LOG_RES(mp),
531 0, XFS_TRANS_PERM_LOG_RES,
532 XFS_WRITE_LOG_COUNT);
533 if (error) {
534 xfs_trans_cancel(tp, 0);
535 return XFS_ERROR(error);
536 }
537 xfs_ilock(ip, XFS_ILOCK_EXCL);
538 xfs_trans_ijoin(tp, ip);
539
540 xfs_bmap_init(&free_list, &first_block);
541
542 /*
543 * it is possible that the extents have changed since
544 * we did the read call as we dropped the ilock for a
545 * while. We have to be careful about truncates or hole
546 * punchs here - we are not allowed to allocate
547 * non-delalloc blocks here.
548 *
549 * The only protection against truncation is the pages
550 * for the range we are being asked to convert are
551 * locked and hence a truncate will block on them
552 * first.
553 *
554 * As a result, if we go beyond the range we really
555 * need and hit an delalloc extent boundary followed by
556 * a hole while we have excess blocks in the map, we
557 * will fill the hole incorrectly and overrun the
558 * transaction reservation.
559 *
560 * Using a single map prevents this as we are forced to
561 * check each map we look for overlap with the desired
562 * range and abort as soon as we find it. Also, given
563 * that we only return a single map, having one beyond
564 * what we can return is probably a bit silly.
565 *
566 * We also need to check that we don't go beyond EOF;
567 * this is a truncate optimisation as a truncate sets
568 * the new file size before block on the pages we
569 * currently have locked under writeback. Because they
570 * are about to be tossed, we don't need to write them
571 * back....
572 */
573 nimaps = 1;
574 end_fsb = XFS_B_TO_FSB(mp, ip->i_size);
575 error = xfs_bmap_last_offset(NULL, ip, &last_block,
576 XFS_DATA_FORK);
577 if (error)
578 goto trans_cancel;
579
580 last_block = XFS_FILEOFF_MAX(last_block, end_fsb);
581 if ((map_start_fsb + count_fsb) > last_block) {
582 count_fsb = last_block - map_start_fsb;
583 if (count_fsb == 0) {
584 error = EAGAIN;
585 goto trans_cancel;
586 }
587 }
588
589 /*
590 * Go get the actual blocks.
591 *
592 * From this point onwards we overwrite the imap
593 * pointer that the caller gave to us.
594 */
595 error = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
596 XFS_BMAPI_WRITE, &first_block, 1,
597 imap, &nimaps, &free_list);
598 if (error)
599 goto trans_cancel;
600
601 error = xfs_bmap_finish(&tp, &free_list, &committed);
602 if (error)
603 goto trans_cancel;
604
605 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
606 if (error)
607 goto error0;
608
609 xfs_iunlock(ip, XFS_ILOCK_EXCL);
610 }
611
612 /*
613 * See if we were able to allocate an extent that
614 * covers at least part of the callers request
615 */
616 if (!(imap->br_startblock || XFS_IS_REALTIME_INODE(ip)))
617 return xfs_alert_fsblock_zero(ip, imap);
618
619 if ((offset_fsb >= imap->br_startoff) &&
620 (offset_fsb < (imap->br_startoff +
621 imap->br_blockcount))) {
622 XFS_STATS_INC(xs_xstrat_quick);
623 return 0;
624 }
625
626 /*
627 * So far we have not mapped the requested part of the
628 * file, just surrounding data, try again.
629 */
630 count_fsb -= imap->br_blockcount;
631 map_start_fsb = imap->br_startoff + imap->br_blockcount;
632 }
633
634 trans_cancel:
635 xfs_bmap_cancel(&free_list);
636 xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
637 error0:
638 xfs_iunlock(ip, XFS_ILOCK_EXCL);
639 return XFS_ERROR(error);
640 }
641
642 int
xfs_iomap_write_unwritten(xfs_inode_t * ip,xfs_off_t offset,size_t count)643 xfs_iomap_write_unwritten(
644 xfs_inode_t *ip,
645 xfs_off_t offset,
646 size_t count)
647 {
648 xfs_mount_t *mp = ip->i_mount;
649 xfs_fileoff_t offset_fsb;
650 xfs_filblks_t count_fsb;
651 xfs_filblks_t numblks_fsb;
652 xfs_fsblock_t firstfsb;
653 int nimaps;
654 xfs_trans_t *tp;
655 xfs_bmbt_irec_t imap;
656 xfs_bmap_free_t free_list;
657 uint resblks;
658 int committed;
659 int error;
660
661 trace_xfs_unwritten_convert(ip, offset, count);
662
663 offset_fsb = XFS_B_TO_FSBT(mp, offset);
664 count_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
665 count_fsb = (xfs_filblks_t)(count_fsb - offset_fsb);
666
667 /*
668 * Reserve enough blocks in this transaction for two complete extent
669 * btree splits. We may be converting the middle part of an unwritten
670 * extent and in this case we will insert two new extents in the btree
671 * each of which could cause a full split.
672 *
673 * This reservation amount will be used in the first call to
674 * xfs_bmbt_split() to select an AG with enough space to satisfy the
675 * rest of the operation.
676 */
677 resblks = XFS_DIOSTRAT_SPACE_RES(mp, 0) << 1;
678
679 do {
680 /*
681 * set up a transaction to convert the range of extents
682 * from unwritten to real. Do allocations in a loop until
683 * we have covered the range passed in.
684 *
685 * Note that we open code the transaction allocation here
686 * to pass KM_NOFS--we can't risk to recursing back into
687 * the filesystem here as we might be asked to write out
688 * the same inode that we complete here and might deadlock
689 * on the iolock.
690 */
691 xfs_wait_for_freeze(mp, SB_FREEZE_TRANS);
692 tp = _xfs_trans_alloc(mp, XFS_TRANS_STRAT_WRITE, KM_NOFS);
693 tp->t_flags |= XFS_TRANS_RESERVE;
694 error = xfs_trans_reserve(tp, resblks,
695 XFS_WRITE_LOG_RES(mp), 0,
696 XFS_TRANS_PERM_LOG_RES,
697 XFS_WRITE_LOG_COUNT);
698 if (error) {
699 xfs_trans_cancel(tp, 0);
700 return XFS_ERROR(error);
701 }
702
703 xfs_ilock(ip, XFS_ILOCK_EXCL);
704 xfs_trans_ijoin(tp, ip);
705
706 /*
707 * Modify the unwritten extent state of the buffer.
708 */
709 xfs_bmap_init(&free_list, &firstfsb);
710 nimaps = 1;
711 error = xfs_bmapi(tp, ip, offset_fsb, count_fsb,
712 XFS_BMAPI_WRITE|XFS_BMAPI_CONVERT, &firstfsb,
713 1, &imap, &nimaps, &free_list);
714 if (error)
715 goto error_on_bmapi_transaction;
716
717 error = xfs_bmap_finish(&(tp), &(free_list), &committed);
718 if (error)
719 goto error_on_bmapi_transaction;
720
721 error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
722 xfs_iunlock(ip, XFS_ILOCK_EXCL);
723 if (error)
724 return XFS_ERROR(error);
725
726 if (!(imap.br_startblock || XFS_IS_REALTIME_INODE(ip)))
727 return xfs_alert_fsblock_zero(ip, &imap);
728
729 if ((numblks_fsb = imap.br_blockcount) == 0) {
730 /*
731 * The numblks_fsb value should always get
732 * smaller, otherwise the loop is stuck.
733 */
734 ASSERT(imap.br_blockcount);
735 break;
736 }
737 offset_fsb += numblks_fsb;
738 count_fsb -= numblks_fsb;
739 } while (count_fsb > 0);
740
741 return 0;
742
743 error_on_bmapi_transaction:
744 xfs_bmap_cancel(&free_list);
745 xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT));
746 xfs_iunlock(ip, XFS_ILOCK_EXCL);
747 return XFS_ERROR(error);
748 }
749