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3993baeb DW |
1 | /* |
2 | * Copyright (C) 2016 Oracle. All Rights Reserved. | |
3 | * | |
4 | * Author: Darrick J. Wong <darrick.wong@oracle.com> | |
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 | |
8 | * as published by the Free Software Foundation; either version 2 | |
9 | * of the License, or (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it would be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write the Free Software Foundation, | |
18 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. | |
19 | */ | |
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_da_format.h" | |
29 | #include "xfs_da_btree.h" | |
30 | #include "xfs_inode.h" | |
31 | #include "xfs_trans.h" | |
32 | #include "xfs_inode_item.h" | |
33 | #include "xfs_bmap.h" | |
34 | #include "xfs_bmap_util.h" | |
35 | #include "xfs_error.h" | |
36 | #include "xfs_dir2.h" | |
37 | #include "xfs_dir2_priv.h" | |
38 | #include "xfs_ioctl.h" | |
39 | #include "xfs_trace.h" | |
40 | #include "xfs_log.h" | |
41 | #include "xfs_icache.h" | |
42 | #include "xfs_pnfs.h" | |
174edb0e | 43 | #include "xfs_btree.h" |
3993baeb DW |
44 | #include "xfs_refcount_btree.h" |
45 | #include "xfs_refcount.h" | |
46 | #include "xfs_bmap_btree.h" | |
47 | #include "xfs_trans_space.h" | |
48 | #include "xfs_bit.h" | |
49 | #include "xfs_alloc.h" | |
50 | #include "xfs_quota_defs.h" | |
51 | #include "xfs_quota.h" | |
52 | #include "xfs_btree.h" | |
53 | #include "xfs_bmap_btree.h" | |
54 | #include "xfs_reflink.h" | |
2a06705c | 55 | #include "xfs_iomap.h" |
43caeb18 | 56 | #include "xfs_rmap_btree.h" |
3993baeb DW |
57 | |
58 | /* | |
59 | * Copy on Write of Shared Blocks | |
60 | * | |
61 | * XFS must preserve "the usual" file semantics even when two files share | |
62 | * the same physical blocks. This means that a write to one file must not | |
63 | * alter the blocks in a different file; the way that we'll do that is | |
64 | * through the use of a copy-on-write mechanism. At a high level, that | |
65 | * means that when we want to write to a shared block, we allocate a new | |
66 | * block, write the data to the new block, and if that succeeds we map the | |
67 | * new block into the file. | |
68 | * | |
69 | * XFS provides a "delayed allocation" mechanism that defers the allocation | |
70 | * of disk blocks to dirty-but-not-yet-mapped file blocks as long as | |
71 | * possible. This reduces fragmentation by enabling the filesystem to ask | |
72 | * for bigger chunks less often, which is exactly what we want for CoW. | |
73 | * | |
74 | * The delalloc mechanism begins when the kernel wants to make a block | |
75 | * writable (write_begin or page_mkwrite). If the offset is not mapped, we | |
76 | * create a delalloc mapping, which is a regular in-core extent, but without | |
77 | * a real startblock. (For delalloc mappings, the startblock encodes both | |
78 | * a flag that this is a delalloc mapping, and a worst-case estimate of how | |
79 | * many blocks might be required to put the mapping into the BMBT.) delalloc | |
80 | * mappings are a reservation against the free space in the filesystem; | |
81 | * adjacent mappings can also be combined into fewer larger mappings. | |
82 | * | |
83 | * When dirty pages are being written out (typically in writepage), the | |
84 | * delalloc reservations are converted into real mappings by allocating | |
85 | * blocks and replacing the delalloc mapping with real ones. A delalloc | |
86 | * mapping can be replaced by several real ones if the free space is | |
87 | * fragmented. | |
88 | * | |
89 | * We want to adapt the delalloc mechanism for copy-on-write, since the | |
90 | * write paths are similar. The first two steps (creating the reservation | |
91 | * and allocating the blocks) are exactly the same as delalloc except that | |
92 | * the mappings must be stored in a separate CoW fork because we do not want | |
93 | * to disturb the mapping in the data fork until we're sure that the write | |
94 | * succeeded. IO completion in this case is the process of removing the old | |
95 | * mapping from the data fork and moving the new mapping from the CoW fork to | |
96 | * the data fork. This will be discussed shortly. | |
97 | * | |
98 | * For now, unaligned directio writes will be bounced back to the page cache. | |
99 | * Block-aligned directio writes will use the same mechanism as buffered | |
100 | * writes. | |
101 | * | |
102 | * CoW remapping must be done after the data block write completes, | |
103 | * because we don't want to destroy the old data fork map until we're sure | |
104 | * the new block has been written. Since the new mappings are kept in a | |
105 | * separate fork, we can simply iterate these mappings to find the ones | |
106 | * that cover the file blocks that we just CoW'd. For each extent, simply | |
107 | * unmap the corresponding range in the data fork, map the new range into | |
108 | * the data fork, and remove the extent from the CoW fork. | |
109 | * | |
110 | * Since the remapping operation can be applied to an arbitrary file | |
111 | * range, we record the need for the remap step as a flag in the ioend | |
112 | * instead of declaring a new IO type. This is required for direct io | |
113 | * because we only have ioend for the whole dio, and we have to be able to | |
114 | * remember the presence of unwritten blocks and CoW blocks with a single | |
115 | * ioend structure. Better yet, the more ground we can cover with one | |
116 | * ioend, the better. | |
117 | */ | |
2a06705c DW |
118 | |
119 | /* | |
120 | * Given an AG extent, find the lowest-numbered run of shared blocks | |
121 | * within that range and return the range in fbno/flen. If | |
122 | * find_end_of_shared is true, return the longest contiguous extent of | |
123 | * shared blocks. If there are no shared extents, fbno and flen will | |
124 | * be set to NULLAGBLOCK and 0, respectively. | |
125 | */ | |
126 | int | |
127 | xfs_reflink_find_shared( | |
128 | struct xfs_mount *mp, | |
129 | xfs_agnumber_t agno, | |
130 | xfs_agblock_t agbno, | |
131 | xfs_extlen_t aglen, | |
132 | xfs_agblock_t *fbno, | |
133 | xfs_extlen_t *flen, | |
134 | bool find_end_of_shared) | |
135 | { | |
136 | struct xfs_buf *agbp; | |
137 | struct xfs_btree_cur *cur; | |
138 | int error; | |
139 | ||
140 | error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp); | |
141 | if (error) | |
142 | return error; | |
143 | ||
144 | cur = xfs_refcountbt_init_cursor(mp, NULL, agbp, agno, NULL); | |
145 | ||
146 | error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen, | |
147 | find_end_of_shared); | |
148 | ||
149 | xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR); | |
150 | ||
151 | xfs_buf_relse(agbp); | |
152 | return error; | |
153 | } | |
154 | ||
155 | /* | |
156 | * Trim the mapping to the next block where there's a change in the | |
157 | * shared/unshared status. More specifically, this means that we | |
158 | * find the lowest-numbered extent of shared blocks that coincides with | |
159 | * the given block mapping. If the shared extent overlaps the start of | |
160 | * the mapping, trim the mapping to the end of the shared extent. If | |
161 | * the shared region intersects the mapping, trim the mapping to the | |
162 | * start of the shared extent. If there are no shared regions that | |
163 | * overlap, just return the original extent. | |
164 | */ | |
165 | int | |
166 | xfs_reflink_trim_around_shared( | |
167 | struct xfs_inode *ip, | |
168 | struct xfs_bmbt_irec *irec, | |
169 | bool *shared, | |
170 | bool *trimmed) | |
171 | { | |
172 | xfs_agnumber_t agno; | |
173 | xfs_agblock_t agbno; | |
174 | xfs_extlen_t aglen; | |
175 | xfs_agblock_t fbno; | |
176 | xfs_extlen_t flen; | |
177 | int error = 0; | |
178 | ||
179 | /* Holes, unwritten, and delalloc extents cannot be shared */ | |
180 | if (!xfs_is_reflink_inode(ip) || | |
181 | ISUNWRITTEN(irec) || | |
182 | irec->br_startblock == HOLESTARTBLOCK || | |
183 | irec->br_startblock == DELAYSTARTBLOCK) { | |
184 | *shared = false; | |
185 | return 0; | |
186 | } | |
187 | ||
188 | trace_xfs_reflink_trim_around_shared(ip, irec); | |
189 | ||
190 | agno = XFS_FSB_TO_AGNO(ip->i_mount, irec->br_startblock); | |
191 | agbno = XFS_FSB_TO_AGBNO(ip->i_mount, irec->br_startblock); | |
192 | aglen = irec->br_blockcount; | |
193 | ||
194 | error = xfs_reflink_find_shared(ip->i_mount, agno, agbno, | |
195 | aglen, &fbno, &flen, true); | |
196 | if (error) | |
197 | return error; | |
198 | ||
199 | *shared = *trimmed = false; | |
200 | if (fbno == NULLAGBLOCK) { | |
201 | /* No shared blocks at all. */ | |
202 | return 0; | |
203 | } else if (fbno == agbno) { | |
204 | /* | |
205 | * The start of this extent is shared. Truncate the | |
206 | * mapping at the end of the shared region so that a | |
207 | * subsequent iteration starts at the start of the | |
208 | * unshared region. | |
209 | */ | |
210 | irec->br_blockcount = flen; | |
211 | *shared = true; | |
212 | if (flen != aglen) | |
213 | *trimmed = true; | |
214 | return 0; | |
215 | } else { | |
216 | /* | |
217 | * There's a shared extent midway through this extent. | |
218 | * Truncate the mapping at the start of the shared | |
219 | * extent so that a subsequent iteration starts at the | |
220 | * start of the shared region. | |
221 | */ | |
222 | irec->br_blockcount = fbno - agbno; | |
223 | *trimmed = true; | |
224 | return 0; | |
225 | } | |
226 | } | |
227 | ||
228 | /* Create a CoW reservation for a range of blocks within a file. */ | |
229 | static int | |
230 | __xfs_reflink_reserve_cow( | |
231 | struct xfs_inode *ip, | |
232 | xfs_fileoff_t *offset_fsb, | |
0613f16c DW |
233 | xfs_fileoff_t end_fsb, |
234 | bool *skipped) | |
2a06705c DW |
235 | { |
236 | struct xfs_bmbt_irec got, prev, imap; | |
237 | xfs_fileoff_t orig_end_fsb; | |
238 | int nimaps, eof = 0, error = 0; | |
239 | bool shared = false, trimmed = false; | |
240 | xfs_extnum_t idx; | |
241 | ||
242 | /* Already reserved? Skip the refcount btree access. */ | |
243 | xfs_bmap_search_extents(ip, *offset_fsb, XFS_COW_FORK, &eof, &idx, | |
244 | &got, &prev); | |
245 | if (!eof && got.br_startoff <= *offset_fsb) { | |
246 | end_fsb = orig_end_fsb = got.br_startoff + got.br_blockcount; | |
247 | trace_xfs_reflink_cow_found(ip, &got); | |
248 | goto done; | |
249 | } | |
250 | ||
251 | /* Read extent from the source file. */ | |
252 | nimaps = 1; | |
253 | error = xfs_bmapi_read(ip, *offset_fsb, end_fsb - *offset_fsb, | |
254 | &imap, &nimaps, 0); | |
255 | if (error) | |
256 | goto out_unlock; | |
257 | ASSERT(nimaps == 1); | |
258 | ||
259 | /* Trim the mapping to the nearest shared extent boundary. */ | |
260 | error = xfs_reflink_trim_around_shared(ip, &imap, &shared, &trimmed); | |
261 | if (error) | |
262 | goto out_unlock; | |
263 | ||
264 | end_fsb = orig_end_fsb = imap.br_startoff + imap.br_blockcount; | |
265 | ||
266 | /* Not shared? Just report the (potentially capped) extent. */ | |
0613f16c DW |
267 | if (!shared) { |
268 | *skipped = true; | |
2a06705c | 269 | goto done; |
0613f16c | 270 | } |
2a06705c DW |
271 | |
272 | /* | |
273 | * Fork all the shared blocks from our write offset until the end of | |
274 | * the extent. | |
275 | */ | |
276 | error = xfs_qm_dqattach_locked(ip, 0); | |
277 | if (error) | |
278 | goto out_unlock; | |
279 | ||
280 | retry: | |
281 | error = xfs_bmapi_reserve_delalloc(ip, XFS_COW_FORK, *offset_fsb, | |
282 | end_fsb - *offset_fsb, &got, | |
283 | &prev, &idx, eof); | |
284 | switch (error) { | |
285 | case 0: | |
286 | break; | |
287 | case -ENOSPC: | |
288 | case -EDQUOT: | |
289 | /* retry without any preallocation */ | |
290 | trace_xfs_reflink_cow_enospc(ip, &imap); | |
291 | if (end_fsb != orig_end_fsb) { | |
292 | end_fsb = orig_end_fsb; | |
293 | goto retry; | |
294 | } | |
295 | /*FALLTHRU*/ | |
296 | default: | |
297 | goto out_unlock; | |
298 | } | |
299 | ||
300 | trace_xfs_reflink_cow_alloc(ip, &got); | |
301 | done: | |
302 | *offset_fsb = end_fsb; | |
303 | out_unlock: | |
304 | return error; | |
305 | } | |
306 | ||
307 | /* Create a CoW reservation for part of a file. */ | |
308 | int | |
309 | xfs_reflink_reserve_cow_range( | |
310 | struct xfs_inode *ip, | |
311 | xfs_off_t offset, | |
312 | xfs_off_t count) | |
313 | { | |
314 | struct xfs_mount *mp = ip->i_mount; | |
315 | xfs_fileoff_t offset_fsb, end_fsb; | |
0613f16c | 316 | bool skipped = false; |
2a06705c DW |
317 | int error; |
318 | ||
319 | trace_xfs_reflink_reserve_cow_range(ip, offset, count); | |
320 | ||
321 | offset_fsb = XFS_B_TO_FSBT(mp, offset); | |
322 | end_fsb = XFS_B_TO_FSB(mp, offset + count); | |
323 | ||
324 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
325 | while (offset_fsb < end_fsb) { | |
0613f16c DW |
326 | error = __xfs_reflink_reserve_cow(ip, &offset_fsb, end_fsb, |
327 | &skipped); | |
2a06705c DW |
328 | if (error) { |
329 | trace_xfs_reflink_reserve_cow_range_error(ip, error, | |
330 | _RET_IP_); | |
331 | break; | |
332 | } | |
333 | } | |
334 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
335 | ||
336 | return error; | |
337 | } | |
ef473667 | 338 | |
0613f16c DW |
339 | /* Allocate all CoW reservations covering a range of blocks in a file. */ |
340 | static int | |
341 | __xfs_reflink_allocate_cow( | |
342 | struct xfs_inode *ip, | |
343 | xfs_fileoff_t *offset_fsb, | |
344 | xfs_fileoff_t end_fsb) | |
345 | { | |
346 | struct xfs_mount *mp = ip->i_mount; | |
347 | struct xfs_bmbt_irec imap; | |
348 | struct xfs_defer_ops dfops; | |
349 | struct xfs_trans *tp; | |
350 | xfs_fsblock_t first_block; | |
351 | xfs_fileoff_t next_fsb; | |
352 | int nimaps = 1, error; | |
353 | bool skipped = false; | |
354 | ||
355 | xfs_defer_init(&dfops, &first_block); | |
356 | ||
357 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, | |
358 | XFS_TRANS_RESERVE, &tp); | |
359 | if (error) | |
360 | return error; | |
361 | ||
362 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
363 | ||
364 | next_fsb = *offset_fsb; | |
365 | error = __xfs_reflink_reserve_cow(ip, &next_fsb, end_fsb, &skipped); | |
366 | if (error) | |
367 | goto out_trans_cancel; | |
368 | ||
369 | if (skipped) { | |
370 | *offset_fsb = next_fsb; | |
371 | goto out_trans_cancel; | |
372 | } | |
373 | ||
374 | xfs_trans_ijoin(tp, ip, 0); | |
375 | error = xfs_bmapi_write(tp, ip, *offset_fsb, next_fsb - *offset_fsb, | |
376 | XFS_BMAPI_COWFORK, &first_block, | |
377 | XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), | |
378 | &imap, &nimaps, &dfops); | |
379 | if (error) | |
380 | goto out_trans_cancel; | |
381 | ||
382 | /* We might not have been able to map the whole delalloc extent */ | |
383 | *offset_fsb = min(*offset_fsb + imap.br_blockcount, next_fsb); | |
384 | ||
385 | error = xfs_defer_finish(&tp, &dfops, NULL); | |
386 | if (error) | |
387 | goto out_trans_cancel; | |
388 | ||
389 | error = xfs_trans_commit(tp); | |
390 | ||
391 | out_unlock: | |
392 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
393 | return error; | |
394 | out_trans_cancel: | |
395 | xfs_defer_cancel(&dfops); | |
396 | xfs_trans_cancel(tp); | |
397 | goto out_unlock; | |
398 | } | |
399 | ||
400 | /* Allocate all CoW reservations covering a part of a file. */ | |
401 | int | |
402 | xfs_reflink_allocate_cow_range( | |
403 | struct xfs_inode *ip, | |
404 | xfs_off_t offset, | |
405 | xfs_off_t count) | |
406 | { | |
407 | struct xfs_mount *mp = ip->i_mount; | |
408 | xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); | |
409 | xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count); | |
410 | int error; | |
411 | ||
412 | ASSERT(xfs_is_reflink_inode(ip)); | |
413 | ||
414 | trace_xfs_reflink_allocate_cow_range(ip, offset, count); | |
415 | ||
416 | /* | |
417 | * Make sure that the dquots are there. | |
418 | */ | |
419 | error = xfs_qm_dqattach(ip, 0); | |
420 | if (error) | |
421 | return error; | |
422 | ||
423 | while (offset_fsb < end_fsb) { | |
424 | error = __xfs_reflink_allocate_cow(ip, &offset_fsb, end_fsb); | |
425 | if (error) { | |
426 | trace_xfs_reflink_allocate_cow_range_error(ip, error, | |
427 | _RET_IP_); | |
428 | break; | |
429 | } | |
430 | } | |
431 | ||
432 | return error; | |
433 | } | |
434 | ||
ef473667 DW |
435 | /* |
436 | * Find the CoW reservation (and whether or not it needs block allocation) | |
437 | * for a given byte offset of a file. | |
438 | */ | |
439 | bool | |
440 | xfs_reflink_find_cow_mapping( | |
441 | struct xfs_inode *ip, | |
442 | xfs_off_t offset, | |
443 | struct xfs_bmbt_irec *imap, | |
444 | bool *need_alloc) | |
445 | { | |
446 | struct xfs_bmbt_irec irec; | |
447 | struct xfs_ifork *ifp; | |
448 | struct xfs_bmbt_rec_host *gotp; | |
449 | xfs_fileoff_t bno; | |
450 | xfs_extnum_t idx; | |
451 | ||
452 | ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED)); | |
453 | ASSERT(xfs_is_reflink_inode(ip)); | |
454 | ||
455 | /* Find the extent in the CoW fork. */ | |
456 | ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK); | |
457 | bno = XFS_B_TO_FSBT(ip->i_mount, offset); | |
458 | gotp = xfs_iext_bno_to_ext(ifp, bno, &idx); | |
459 | if (!gotp) | |
460 | return false; | |
461 | ||
462 | xfs_bmbt_get_all(gotp, &irec); | |
463 | if (bno >= irec.br_startoff + irec.br_blockcount || | |
464 | bno < irec.br_startoff) | |
465 | return false; | |
466 | ||
467 | trace_xfs_reflink_find_cow_mapping(ip, offset, 1, XFS_IO_OVERWRITE, | |
468 | &irec); | |
469 | ||
470 | /* If it's still delalloc, we must allocate later. */ | |
471 | *imap = irec; | |
472 | *need_alloc = !!(isnullstartblock(irec.br_startblock)); | |
473 | ||
474 | return true; | |
475 | } | |
476 | ||
477 | /* | |
478 | * Trim an extent to end at the next CoW reservation past offset_fsb. | |
479 | */ | |
480 | int | |
481 | xfs_reflink_trim_irec_to_next_cow( | |
482 | struct xfs_inode *ip, | |
483 | xfs_fileoff_t offset_fsb, | |
484 | struct xfs_bmbt_irec *imap) | |
485 | { | |
486 | struct xfs_bmbt_irec irec; | |
487 | struct xfs_ifork *ifp; | |
488 | struct xfs_bmbt_rec_host *gotp; | |
489 | xfs_extnum_t idx; | |
490 | ||
491 | if (!xfs_is_reflink_inode(ip)) | |
492 | return 0; | |
493 | ||
494 | /* Find the extent in the CoW fork. */ | |
495 | ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK); | |
496 | gotp = xfs_iext_bno_to_ext(ifp, offset_fsb, &idx); | |
497 | if (!gotp) | |
498 | return 0; | |
499 | xfs_bmbt_get_all(gotp, &irec); | |
500 | ||
501 | /* This is the extent before; try sliding up one. */ | |
502 | if (irec.br_startoff < offset_fsb) { | |
503 | idx++; | |
504 | if (idx >= ifp->if_bytes / sizeof(xfs_bmbt_rec_t)) | |
505 | return 0; | |
506 | gotp = xfs_iext_get_ext(ifp, idx); | |
507 | xfs_bmbt_get_all(gotp, &irec); | |
508 | } | |
509 | ||
510 | if (irec.br_startoff >= imap->br_startoff + imap->br_blockcount) | |
511 | return 0; | |
512 | ||
513 | imap->br_blockcount = irec.br_startoff - imap->br_startoff; | |
514 | trace_xfs_reflink_trim_irec(ip, imap); | |
515 | ||
516 | return 0; | |
517 | } | |
43caeb18 DW |
518 | |
519 | /* | |
520 | * Cancel all pending CoW reservations for some block range of an inode. | |
521 | */ | |
522 | int | |
523 | xfs_reflink_cancel_cow_blocks( | |
524 | struct xfs_inode *ip, | |
525 | struct xfs_trans **tpp, | |
526 | xfs_fileoff_t offset_fsb, | |
527 | xfs_fileoff_t end_fsb) | |
528 | { | |
529 | struct xfs_bmbt_irec irec; | |
530 | xfs_filblks_t count_fsb; | |
531 | xfs_fsblock_t firstfsb; | |
532 | struct xfs_defer_ops dfops; | |
533 | int error = 0; | |
534 | int nimaps; | |
535 | ||
536 | if (!xfs_is_reflink_inode(ip)) | |
537 | return 0; | |
538 | ||
539 | /* Go find the old extent in the CoW fork. */ | |
540 | while (offset_fsb < end_fsb) { | |
541 | nimaps = 1; | |
542 | count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb); | |
543 | error = xfs_bmapi_read(ip, offset_fsb, count_fsb, &irec, | |
544 | &nimaps, XFS_BMAPI_COWFORK); | |
545 | if (error) | |
546 | break; | |
547 | ASSERT(nimaps == 1); | |
548 | ||
549 | trace_xfs_reflink_cancel_cow(ip, &irec); | |
550 | ||
551 | if (irec.br_startblock == DELAYSTARTBLOCK) { | |
552 | /* Free a delayed allocation. */ | |
553 | xfs_mod_fdblocks(ip->i_mount, irec.br_blockcount, | |
554 | false); | |
555 | ip->i_delayed_blks -= irec.br_blockcount; | |
556 | ||
557 | /* Remove the mapping from the CoW fork. */ | |
558 | error = xfs_bunmapi_cow(ip, &irec); | |
559 | if (error) | |
560 | break; | |
561 | } else if (irec.br_startblock == HOLESTARTBLOCK) { | |
562 | /* empty */ | |
563 | } else { | |
564 | xfs_trans_ijoin(*tpp, ip, 0); | |
565 | xfs_defer_init(&dfops, &firstfsb); | |
566 | ||
174edb0e DW |
567 | /* Free the CoW orphan record. */ |
568 | error = xfs_refcount_free_cow_extent(ip->i_mount, | |
569 | &dfops, irec.br_startblock, | |
570 | irec.br_blockcount); | |
571 | if (error) | |
572 | break; | |
573 | ||
43caeb18 DW |
574 | xfs_bmap_add_free(ip->i_mount, &dfops, |
575 | irec.br_startblock, irec.br_blockcount, | |
576 | NULL); | |
577 | ||
578 | /* Update quota accounting */ | |
579 | xfs_trans_mod_dquot_byino(*tpp, ip, XFS_TRANS_DQ_BCOUNT, | |
580 | -(long)irec.br_blockcount); | |
581 | ||
582 | /* Roll the transaction */ | |
583 | error = xfs_defer_finish(tpp, &dfops, ip); | |
584 | if (error) { | |
585 | xfs_defer_cancel(&dfops); | |
586 | break; | |
587 | } | |
588 | ||
589 | /* Remove the mapping from the CoW fork. */ | |
590 | error = xfs_bunmapi_cow(ip, &irec); | |
591 | if (error) | |
592 | break; | |
593 | } | |
594 | ||
595 | /* Roll on... */ | |
596 | offset_fsb = irec.br_startoff + irec.br_blockcount; | |
597 | } | |
598 | ||
599 | return error; | |
600 | } | |
601 | ||
602 | /* | |
603 | * Cancel all pending CoW reservations for some byte range of an inode. | |
604 | */ | |
605 | int | |
606 | xfs_reflink_cancel_cow_range( | |
607 | struct xfs_inode *ip, | |
608 | xfs_off_t offset, | |
609 | xfs_off_t count) | |
610 | { | |
611 | struct xfs_trans *tp; | |
612 | xfs_fileoff_t offset_fsb; | |
613 | xfs_fileoff_t end_fsb; | |
614 | int error; | |
615 | ||
616 | trace_xfs_reflink_cancel_cow_range(ip, offset, count); | |
617 | ||
618 | offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); | |
619 | if (count == NULLFILEOFF) | |
620 | end_fsb = NULLFILEOFF; | |
621 | else | |
622 | end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); | |
623 | ||
624 | /* Start a rolling transaction to remove the mappings */ | |
625 | error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write, | |
626 | 0, 0, 0, &tp); | |
627 | if (error) | |
628 | goto out; | |
629 | ||
630 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
631 | xfs_trans_ijoin(tp, ip, 0); | |
632 | ||
633 | /* Scrape out the old CoW reservations */ | |
634 | error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb); | |
635 | if (error) | |
636 | goto out_cancel; | |
637 | ||
638 | error = xfs_trans_commit(tp); | |
639 | ||
640 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
641 | return error; | |
642 | ||
643 | out_cancel: | |
644 | xfs_trans_cancel(tp); | |
645 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
646 | out: | |
647 | trace_xfs_reflink_cancel_cow_range_error(ip, error, _RET_IP_); | |
648 | return error; | |
649 | } | |
650 | ||
651 | /* | |
652 | * Remap parts of a file's data fork after a successful CoW. | |
653 | */ | |
654 | int | |
655 | xfs_reflink_end_cow( | |
656 | struct xfs_inode *ip, | |
657 | xfs_off_t offset, | |
658 | xfs_off_t count) | |
659 | { | |
660 | struct xfs_bmbt_irec irec; | |
661 | struct xfs_bmbt_irec uirec; | |
662 | struct xfs_trans *tp; | |
663 | xfs_fileoff_t offset_fsb; | |
664 | xfs_fileoff_t end_fsb; | |
665 | xfs_filblks_t count_fsb; | |
666 | xfs_fsblock_t firstfsb; | |
667 | struct xfs_defer_ops dfops; | |
668 | int error; | |
669 | unsigned int resblks; | |
670 | xfs_filblks_t ilen; | |
671 | xfs_filblks_t rlen; | |
672 | int nimaps; | |
673 | ||
674 | trace_xfs_reflink_end_cow(ip, offset, count); | |
675 | ||
676 | offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); | |
677 | end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); | |
678 | count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb); | |
679 | ||
680 | /* Start a rolling transaction to switch the mappings */ | |
681 | resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK); | |
682 | error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write, | |
683 | resblks, 0, 0, &tp); | |
684 | if (error) | |
685 | goto out; | |
686 | ||
687 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
688 | xfs_trans_ijoin(tp, ip, 0); | |
689 | ||
690 | /* Go find the old extent in the CoW fork. */ | |
691 | while (offset_fsb < end_fsb) { | |
692 | /* Read extent from the source file */ | |
693 | nimaps = 1; | |
694 | count_fsb = (xfs_filblks_t)(end_fsb - offset_fsb); | |
695 | error = xfs_bmapi_read(ip, offset_fsb, count_fsb, &irec, | |
696 | &nimaps, XFS_BMAPI_COWFORK); | |
697 | if (error) | |
698 | goto out_cancel; | |
699 | ASSERT(nimaps == 1); | |
700 | ||
701 | ASSERT(irec.br_startblock != DELAYSTARTBLOCK); | |
702 | trace_xfs_reflink_cow_remap(ip, &irec); | |
703 | ||
704 | /* | |
705 | * We can have a hole in the CoW fork if part of a directio | |
706 | * write is CoW but part of it isn't. | |
707 | */ | |
708 | rlen = ilen = irec.br_blockcount; | |
709 | if (irec.br_startblock == HOLESTARTBLOCK) | |
710 | goto next_extent; | |
711 | ||
712 | /* Unmap the old blocks in the data fork. */ | |
713 | while (rlen) { | |
714 | xfs_defer_init(&dfops, &firstfsb); | |
715 | error = __xfs_bunmapi(tp, ip, irec.br_startoff, | |
716 | &rlen, 0, 1, &firstfsb, &dfops); | |
717 | if (error) | |
718 | goto out_defer; | |
719 | ||
720 | /* | |
721 | * Trim the extent to whatever got unmapped. | |
722 | * Remember, bunmapi works backwards. | |
723 | */ | |
724 | uirec.br_startblock = irec.br_startblock + rlen; | |
725 | uirec.br_startoff = irec.br_startoff + rlen; | |
726 | uirec.br_blockcount = irec.br_blockcount - rlen; | |
727 | irec.br_blockcount = rlen; | |
728 | trace_xfs_reflink_cow_remap_piece(ip, &uirec); | |
729 | ||
174edb0e DW |
730 | /* Free the CoW orphan record. */ |
731 | error = xfs_refcount_free_cow_extent(tp->t_mountp, | |
732 | &dfops, uirec.br_startblock, | |
733 | uirec.br_blockcount); | |
734 | if (error) | |
735 | goto out_defer; | |
736 | ||
43caeb18 DW |
737 | /* Map the new blocks into the data fork. */ |
738 | error = xfs_bmap_map_extent(tp->t_mountp, &dfops, | |
739 | ip, &uirec); | |
740 | if (error) | |
741 | goto out_defer; | |
742 | ||
743 | /* Remove the mapping from the CoW fork. */ | |
744 | error = xfs_bunmapi_cow(ip, &uirec); | |
745 | if (error) | |
746 | goto out_defer; | |
747 | ||
748 | error = xfs_defer_finish(&tp, &dfops, ip); | |
749 | if (error) | |
750 | goto out_defer; | |
751 | } | |
752 | ||
753 | next_extent: | |
754 | /* Roll on... */ | |
755 | offset_fsb = irec.br_startoff + ilen; | |
756 | } | |
757 | ||
758 | error = xfs_trans_commit(tp); | |
759 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
760 | if (error) | |
761 | goto out; | |
762 | return 0; | |
763 | ||
764 | out_defer: | |
765 | xfs_defer_cancel(&dfops); | |
766 | out_cancel: | |
767 | xfs_trans_cancel(tp); | |
768 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
769 | out: | |
770 | trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_); | |
771 | return error; | |
772 | } | |
174edb0e DW |
773 | |
774 | /* | |
775 | * Free leftover CoW reservations that didn't get cleaned out. | |
776 | */ | |
777 | int | |
778 | xfs_reflink_recover_cow( | |
779 | struct xfs_mount *mp) | |
780 | { | |
781 | xfs_agnumber_t agno; | |
782 | int error = 0; | |
783 | ||
784 | if (!xfs_sb_version_hasreflink(&mp->m_sb)) | |
785 | return 0; | |
786 | ||
787 | for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) { | |
788 | error = xfs_refcount_recover_cow_leftovers(mp, agno); | |
789 | if (error) | |
790 | break; | |
791 | } | |
792 | ||
793 | return error; | |
794 | } | |
862bb360 DW |
795 | |
796 | /* | |
797 | * Reflinking (Block) Ranges of Two Files Together | |
798 | * | |
799 | * First, ensure that the reflink flag is set on both inodes. The flag is an | |
800 | * optimization to avoid unnecessary refcount btree lookups in the write path. | |
801 | * | |
802 | * Now we can iteratively remap the range of extents (and holes) in src to the | |
803 | * corresponding ranges in dest. Let drange and srange denote the ranges of | |
804 | * logical blocks in dest and src touched by the reflink operation. | |
805 | * | |
806 | * While the length of drange is greater than zero, | |
807 | * - Read src's bmbt at the start of srange ("imap") | |
808 | * - If imap doesn't exist, make imap appear to start at the end of srange | |
809 | * with zero length. | |
810 | * - If imap starts before srange, advance imap to start at srange. | |
811 | * - If imap goes beyond srange, truncate imap to end at the end of srange. | |
812 | * - Punch (imap start - srange start + imap len) blocks from dest at | |
813 | * offset (drange start). | |
814 | * - If imap points to a real range of pblks, | |
815 | * > Increase the refcount of the imap's pblks | |
816 | * > Map imap's pblks into dest at the offset | |
817 | * (drange start + imap start - srange start) | |
818 | * - Advance drange and srange by (imap start - srange start + imap len) | |
819 | * | |
820 | * Finally, if the reflink made dest longer, update both the in-core and | |
821 | * on-disk file sizes. | |
822 | * | |
823 | * ASCII Art Demonstration: | |
824 | * | |
825 | * Let's say we want to reflink this source file: | |
826 | * | |
827 | * ----SSSSSSS-SSSSS----SSSSSS (src file) | |
828 | * <--------------------> | |
829 | * | |
830 | * into this destination file: | |
831 | * | |
832 | * --DDDDDDDDDDDDDDDDDDD--DDD (dest file) | |
833 | * <--------------------> | |
834 | * '-' means a hole, and 'S' and 'D' are written blocks in the src and dest. | |
835 | * Observe that the range has different logical offsets in either file. | |
836 | * | |
837 | * Consider that the first extent in the source file doesn't line up with our | |
838 | * reflink range. Unmapping and remapping are separate operations, so we can | |
839 | * unmap more blocks from the destination file than we remap. | |
840 | * | |
841 | * ----SSSSSSS-SSSSS----SSSSSS | |
842 | * <-------> | |
843 | * --DDDDD---------DDDDD--DDD | |
844 | * <-------> | |
845 | * | |
846 | * Now remap the source extent into the destination file: | |
847 | * | |
848 | * ----SSSSSSS-SSSSS----SSSSSS | |
849 | * <-------> | |
850 | * --DDDDD--SSSSSSSDDDDD--DDD | |
851 | * <-------> | |
852 | * | |
853 | * Do likewise with the second hole and extent in our range. Holes in the | |
854 | * unmap range don't affect our operation. | |
855 | * | |
856 | * ----SSSSSSS-SSSSS----SSSSSS | |
857 | * <----> | |
858 | * --DDDDD--SSSSSSS-SSSSS-DDD | |
859 | * <----> | |
860 | * | |
861 | * Finally, unmap and remap part of the third extent. This will increase the | |
862 | * size of the destination file. | |
863 | * | |
864 | * ----SSSSSSS-SSSSS----SSSSSS | |
865 | * <-----> | |
866 | * --DDDDD--SSSSSSS-SSSSS----SSS | |
867 | * <-----> | |
868 | * | |
869 | * Once we update the destination file's i_size, we're done. | |
870 | */ | |
871 | ||
872 | /* | |
873 | * Ensure the reflink bit is set in both inodes. | |
874 | */ | |
875 | STATIC int | |
876 | xfs_reflink_set_inode_flag( | |
877 | struct xfs_inode *src, | |
878 | struct xfs_inode *dest) | |
879 | { | |
880 | struct xfs_mount *mp = src->i_mount; | |
881 | int error; | |
882 | struct xfs_trans *tp; | |
883 | ||
884 | if (xfs_is_reflink_inode(src) && xfs_is_reflink_inode(dest)) | |
885 | return 0; | |
886 | ||
887 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); | |
888 | if (error) | |
889 | goto out_error; | |
890 | ||
891 | /* Lock both files against IO */ | |
892 | if (src->i_ino == dest->i_ino) | |
893 | xfs_ilock(src, XFS_ILOCK_EXCL); | |
894 | else | |
895 | xfs_lock_two_inodes(src, dest, XFS_ILOCK_EXCL); | |
896 | ||
897 | if (!xfs_is_reflink_inode(src)) { | |
898 | trace_xfs_reflink_set_inode_flag(src); | |
899 | xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL); | |
900 | src->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK; | |
901 | xfs_trans_log_inode(tp, src, XFS_ILOG_CORE); | |
902 | xfs_ifork_init_cow(src); | |
903 | } else | |
904 | xfs_iunlock(src, XFS_ILOCK_EXCL); | |
905 | ||
906 | if (src->i_ino == dest->i_ino) | |
907 | goto commit_flags; | |
908 | ||
909 | if (!xfs_is_reflink_inode(dest)) { | |
910 | trace_xfs_reflink_set_inode_flag(dest); | |
911 | xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL); | |
912 | dest->i_d.di_flags2 |= XFS_DIFLAG2_REFLINK; | |
913 | xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE); | |
914 | xfs_ifork_init_cow(dest); | |
915 | } else | |
916 | xfs_iunlock(dest, XFS_ILOCK_EXCL); | |
917 | ||
918 | commit_flags: | |
919 | error = xfs_trans_commit(tp); | |
920 | if (error) | |
921 | goto out_error; | |
922 | return error; | |
923 | ||
924 | out_error: | |
925 | trace_xfs_reflink_set_inode_flag_error(dest, error, _RET_IP_); | |
926 | return error; | |
927 | } | |
928 | ||
929 | /* | |
930 | * Update destination inode size, if necessary. | |
931 | */ | |
932 | STATIC int | |
933 | xfs_reflink_update_dest( | |
934 | struct xfs_inode *dest, | |
935 | xfs_off_t newlen) | |
936 | { | |
937 | struct xfs_mount *mp = dest->i_mount; | |
938 | struct xfs_trans *tp; | |
939 | int error; | |
940 | ||
941 | if (newlen <= i_size_read(VFS_I(dest))) | |
942 | return 0; | |
943 | ||
944 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); | |
945 | if (error) | |
946 | goto out_error; | |
947 | ||
948 | xfs_ilock(dest, XFS_ILOCK_EXCL); | |
949 | xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL); | |
950 | ||
951 | trace_xfs_reflink_update_inode_size(dest, newlen); | |
952 | i_size_write(VFS_I(dest), newlen); | |
953 | dest->i_d.di_size = newlen; | |
954 | xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE); | |
955 | ||
956 | error = xfs_trans_commit(tp); | |
957 | if (error) | |
958 | goto out_error; | |
959 | return error; | |
960 | ||
961 | out_error: | |
962 | trace_xfs_reflink_update_inode_size_error(dest, error, _RET_IP_); | |
963 | return error; | |
964 | } | |
965 | ||
966 | /* | |
967 | * Unmap a range of blocks from a file, then map other blocks into the hole. | |
968 | * The range to unmap is (destoff : destoff + srcioff + irec->br_blockcount). | |
969 | * The extent irec is mapped into dest at irec->br_startoff. | |
970 | */ | |
971 | STATIC int | |
972 | xfs_reflink_remap_extent( | |
973 | struct xfs_inode *ip, | |
974 | struct xfs_bmbt_irec *irec, | |
975 | xfs_fileoff_t destoff, | |
976 | xfs_off_t new_isize) | |
977 | { | |
978 | struct xfs_mount *mp = ip->i_mount; | |
979 | struct xfs_trans *tp; | |
980 | xfs_fsblock_t firstfsb; | |
981 | unsigned int resblks; | |
982 | struct xfs_defer_ops dfops; | |
983 | struct xfs_bmbt_irec uirec; | |
984 | bool real_extent; | |
985 | xfs_filblks_t rlen; | |
986 | xfs_filblks_t unmap_len; | |
987 | xfs_off_t newlen; | |
988 | int error; | |
989 | ||
990 | unmap_len = irec->br_startoff + irec->br_blockcount - destoff; | |
991 | trace_xfs_reflink_punch_range(ip, destoff, unmap_len); | |
992 | ||
993 | /* Only remap normal extents. */ | |
994 | real_extent = (irec->br_startblock != HOLESTARTBLOCK && | |
995 | irec->br_startblock != DELAYSTARTBLOCK && | |
996 | !ISUNWRITTEN(irec)); | |
997 | ||
998 | /* Start a rolling transaction to switch the mappings */ | |
999 | resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK); | |
1000 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, 0, &tp); | |
1001 | if (error) | |
1002 | goto out; | |
1003 | ||
1004 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
1005 | xfs_trans_ijoin(tp, ip, 0); | |
1006 | ||
1007 | /* If we're not just clearing space, then do we have enough quota? */ | |
1008 | if (real_extent) { | |
1009 | error = xfs_trans_reserve_quota_nblks(tp, ip, | |
1010 | irec->br_blockcount, 0, XFS_QMOPT_RES_REGBLKS); | |
1011 | if (error) | |
1012 | goto out_cancel; | |
1013 | } | |
1014 | ||
1015 | trace_xfs_reflink_remap(ip, irec->br_startoff, | |
1016 | irec->br_blockcount, irec->br_startblock); | |
1017 | ||
1018 | /* Unmap the old blocks in the data fork. */ | |
1019 | rlen = unmap_len; | |
1020 | while (rlen) { | |
1021 | xfs_defer_init(&dfops, &firstfsb); | |
1022 | error = __xfs_bunmapi(tp, ip, destoff, &rlen, 0, 1, | |
1023 | &firstfsb, &dfops); | |
1024 | if (error) | |
1025 | goto out_defer; | |
1026 | ||
1027 | /* | |
1028 | * Trim the extent to whatever got unmapped. | |
1029 | * Remember, bunmapi works backwards. | |
1030 | */ | |
1031 | uirec.br_startblock = irec->br_startblock + rlen; | |
1032 | uirec.br_startoff = irec->br_startoff + rlen; | |
1033 | uirec.br_blockcount = unmap_len - rlen; | |
1034 | unmap_len = rlen; | |
1035 | ||
1036 | /* If this isn't a real mapping, we're done. */ | |
1037 | if (!real_extent || uirec.br_blockcount == 0) | |
1038 | goto next_extent; | |
1039 | ||
1040 | trace_xfs_reflink_remap(ip, uirec.br_startoff, | |
1041 | uirec.br_blockcount, uirec.br_startblock); | |
1042 | ||
1043 | /* Update the refcount tree */ | |
1044 | error = xfs_refcount_increase_extent(mp, &dfops, &uirec); | |
1045 | if (error) | |
1046 | goto out_defer; | |
1047 | ||
1048 | /* Map the new blocks into the data fork. */ | |
1049 | error = xfs_bmap_map_extent(mp, &dfops, ip, &uirec); | |
1050 | if (error) | |
1051 | goto out_defer; | |
1052 | ||
1053 | /* Update quota accounting. */ | |
1054 | xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, | |
1055 | uirec.br_blockcount); | |
1056 | ||
1057 | /* Update dest isize if needed. */ | |
1058 | newlen = XFS_FSB_TO_B(mp, | |
1059 | uirec.br_startoff + uirec.br_blockcount); | |
1060 | newlen = min_t(xfs_off_t, newlen, new_isize); | |
1061 | if (newlen > i_size_read(VFS_I(ip))) { | |
1062 | trace_xfs_reflink_update_inode_size(ip, newlen); | |
1063 | i_size_write(VFS_I(ip), newlen); | |
1064 | ip->i_d.di_size = newlen; | |
1065 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); | |
1066 | } | |
1067 | ||
1068 | next_extent: | |
1069 | /* Process all the deferred stuff. */ | |
1070 | error = xfs_defer_finish(&tp, &dfops, ip); | |
1071 | if (error) | |
1072 | goto out_defer; | |
1073 | } | |
1074 | ||
1075 | error = xfs_trans_commit(tp); | |
1076 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1077 | if (error) | |
1078 | goto out; | |
1079 | return 0; | |
1080 | ||
1081 | out_defer: | |
1082 | xfs_defer_cancel(&dfops); | |
1083 | out_cancel: | |
1084 | xfs_trans_cancel(tp); | |
1085 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1086 | out: | |
1087 | trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_); | |
1088 | return error; | |
1089 | } | |
1090 | ||
1091 | /* | |
1092 | * Iteratively remap one file's extents (and holes) to another's. | |
1093 | */ | |
1094 | STATIC int | |
1095 | xfs_reflink_remap_blocks( | |
1096 | struct xfs_inode *src, | |
1097 | xfs_fileoff_t srcoff, | |
1098 | struct xfs_inode *dest, | |
1099 | xfs_fileoff_t destoff, | |
1100 | xfs_filblks_t len, | |
1101 | xfs_off_t new_isize) | |
1102 | { | |
1103 | struct xfs_bmbt_irec imap; | |
1104 | int nimaps; | |
1105 | int error = 0; | |
1106 | xfs_filblks_t range_len; | |
1107 | ||
1108 | /* drange = (destoff, destoff + len); srange = (srcoff, srcoff + len) */ | |
1109 | while (len) { | |
1110 | trace_xfs_reflink_remap_blocks_loop(src, srcoff, len, | |
1111 | dest, destoff); | |
1112 | /* Read extent from the source file */ | |
1113 | nimaps = 1; | |
1114 | xfs_ilock(src, XFS_ILOCK_EXCL); | |
1115 | error = xfs_bmapi_read(src, srcoff, len, &imap, &nimaps, 0); | |
1116 | xfs_iunlock(src, XFS_ILOCK_EXCL); | |
1117 | if (error) | |
1118 | goto err; | |
1119 | ASSERT(nimaps == 1); | |
1120 | ||
1121 | trace_xfs_reflink_remap_imap(src, srcoff, len, XFS_IO_OVERWRITE, | |
1122 | &imap); | |
1123 | ||
1124 | /* Translate imap into the destination file. */ | |
1125 | range_len = imap.br_startoff + imap.br_blockcount - srcoff; | |
1126 | imap.br_startoff += destoff - srcoff; | |
1127 | ||
1128 | /* Clear dest from destoff to the end of imap and map it in. */ | |
1129 | error = xfs_reflink_remap_extent(dest, &imap, destoff, | |
1130 | new_isize); | |
1131 | if (error) | |
1132 | goto err; | |
1133 | ||
1134 | if (fatal_signal_pending(current)) { | |
1135 | error = -EINTR; | |
1136 | goto err; | |
1137 | } | |
1138 | ||
1139 | /* Advance drange/srange */ | |
1140 | srcoff += range_len; | |
1141 | destoff += range_len; | |
1142 | len -= range_len; | |
1143 | } | |
1144 | ||
1145 | return 0; | |
1146 | ||
1147 | err: | |
1148 | trace_xfs_reflink_remap_blocks_error(dest, error, _RET_IP_); | |
1149 | return error; | |
1150 | } | |
1151 | ||
cc714660 DW |
1152 | /* |
1153 | * Read a page's worth of file data into the page cache. Return the page | |
1154 | * locked. | |
1155 | */ | |
1156 | static struct page * | |
1157 | xfs_get_page( | |
1158 | struct inode *inode, | |
1159 | xfs_off_t offset) | |
1160 | { | |
1161 | struct address_space *mapping; | |
1162 | struct page *page; | |
1163 | pgoff_t n; | |
1164 | ||
1165 | n = offset >> PAGE_SHIFT; | |
1166 | mapping = inode->i_mapping; | |
1167 | page = read_mapping_page(mapping, n, NULL); | |
1168 | if (IS_ERR(page)) | |
1169 | return page; | |
1170 | if (!PageUptodate(page)) { | |
1171 | put_page(page); | |
1172 | return ERR_PTR(-EIO); | |
1173 | } | |
1174 | lock_page(page); | |
1175 | return page; | |
1176 | } | |
1177 | ||
1178 | /* | |
1179 | * Compare extents of two files to see if they are the same. | |
1180 | */ | |
1181 | static int | |
1182 | xfs_compare_extents( | |
1183 | struct inode *src, | |
1184 | xfs_off_t srcoff, | |
1185 | struct inode *dest, | |
1186 | xfs_off_t destoff, | |
1187 | xfs_off_t len, | |
1188 | bool *is_same) | |
1189 | { | |
1190 | xfs_off_t src_poff; | |
1191 | xfs_off_t dest_poff; | |
1192 | void *src_addr; | |
1193 | void *dest_addr; | |
1194 | struct page *src_page; | |
1195 | struct page *dest_page; | |
1196 | xfs_off_t cmp_len; | |
1197 | bool same; | |
1198 | int error; | |
1199 | ||
1200 | error = -EINVAL; | |
1201 | same = true; | |
1202 | while (len) { | |
1203 | src_poff = srcoff & (PAGE_SIZE - 1); | |
1204 | dest_poff = destoff & (PAGE_SIZE - 1); | |
1205 | cmp_len = min(PAGE_SIZE - src_poff, | |
1206 | PAGE_SIZE - dest_poff); | |
1207 | cmp_len = min(cmp_len, len); | |
1208 | ASSERT(cmp_len > 0); | |
1209 | ||
1210 | trace_xfs_reflink_compare_extents(XFS_I(src), srcoff, cmp_len, | |
1211 | XFS_I(dest), destoff); | |
1212 | ||
1213 | src_page = xfs_get_page(src, srcoff); | |
1214 | if (IS_ERR(src_page)) { | |
1215 | error = PTR_ERR(src_page); | |
1216 | goto out_error; | |
1217 | } | |
1218 | dest_page = xfs_get_page(dest, destoff); | |
1219 | if (IS_ERR(dest_page)) { | |
1220 | error = PTR_ERR(dest_page); | |
1221 | unlock_page(src_page); | |
1222 | put_page(src_page); | |
1223 | goto out_error; | |
1224 | } | |
1225 | src_addr = kmap_atomic(src_page); | |
1226 | dest_addr = kmap_atomic(dest_page); | |
1227 | ||
1228 | flush_dcache_page(src_page); | |
1229 | flush_dcache_page(dest_page); | |
1230 | ||
1231 | if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len)) | |
1232 | same = false; | |
1233 | ||
1234 | kunmap_atomic(dest_addr); | |
1235 | kunmap_atomic(src_addr); | |
1236 | unlock_page(dest_page); | |
1237 | unlock_page(src_page); | |
1238 | put_page(dest_page); | |
1239 | put_page(src_page); | |
1240 | ||
1241 | if (!same) | |
1242 | break; | |
1243 | ||
1244 | srcoff += cmp_len; | |
1245 | destoff += cmp_len; | |
1246 | len -= cmp_len; | |
1247 | } | |
1248 | ||
1249 | *is_same = same; | |
1250 | return 0; | |
1251 | ||
1252 | out_error: | |
1253 | trace_xfs_reflink_compare_extents_error(XFS_I(dest), error, _RET_IP_); | |
1254 | return error; | |
1255 | } | |
1256 | ||
862bb360 DW |
1257 | /* |
1258 | * Link a range of blocks from one file to another. | |
1259 | */ | |
1260 | int | |
1261 | xfs_reflink_remap_range( | |
1262 | struct xfs_inode *src, | |
1263 | xfs_off_t srcoff, | |
1264 | struct xfs_inode *dest, | |
1265 | xfs_off_t destoff, | |
cc714660 DW |
1266 | xfs_off_t len, |
1267 | unsigned int flags) | |
862bb360 DW |
1268 | { |
1269 | struct xfs_mount *mp = src->i_mount; | |
1270 | xfs_fileoff_t sfsbno, dfsbno; | |
1271 | xfs_filblks_t fsblen; | |
1272 | int error; | |
cc714660 | 1273 | bool is_same; |
862bb360 DW |
1274 | |
1275 | if (!xfs_sb_version_hasreflink(&mp->m_sb)) | |
1276 | return -EOPNOTSUPP; | |
1277 | ||
1278 | if (XFS_FORCED_SHUTDOWN(mp)) | |
1279 | return -EIO; | |
1280 | ||
1281 | /* Don't reflink realtime inodes */ | |
1282 | if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest)) | |
1283 | return -EINVAL; | |
1284 | ||
cc714660 DW |
1285 | if (flags & ~XFS_REFLINK_ALL) |
1286 | return -EINVAL; | |
1287 | ||
862bb360 DW |
1288 | trace_xfs_reflink_remap_range(src, srcoff, len, dest, destoff); |
1289 | ||
1290 | /* Lock both files against IO */ | |
1291 | if (src->i_ino == dest->i_ino) { | |
1292 | xfs_ilock(src, XFS_IOLOCK_EXCL); | |
1293 | xfs_ilock(src, XFS_MMAPLOCK_EXCL); | |
1294 | } else { | |
1295 | xfs_lock_two_inodes(src, dest, XFS_IOLOCK_EXCL); | |
1296 | xfs_lock_two_inodes(src, dest, XFS_MMAPLOCK_EXCL); | |
1297 | } | |
1298 | ||
cc714660 DW |
1299 | /* |
1300 | * Check that the extents are the same. | |
1301 | */ | |
1302 | if (flags & XFS_REFLINK_DEDUPE) { | |
1303 | is_same = false; | |
1304 | error = xfs_compare_extents(VFS_I(src), srcoff, VFS_I(dest), | |
1305 | destoff, len, &is_same); | |
1306 | if (error) | |
1307 | goto out_error; | |
1308 | if (!is_same) { | |
1309 | error = -EBADE; | |
1310 | goto out_error; | |
1311 | } | |
1312 | } | |
1313 | ||
862bb360 DW |
1314 | error = xfs_reflink_set_inode_flag(src, dest); |
1315 | if (error) | |
1316 | goto out_error; | |
1317 | ||
1318 | /* | |
1319 | * Invalidate the page cache so that we can clear any CoW mappings | |
1320 | * in the destination file. | |
1321 | */ | |
1322 | truncate_inode_pages_range(&VFS_I(dest)->i_data, destoff, | |
1323 | PAGE_ALIGN(destoff + len) - 1); | |
1324 | ||
1325 | dfsbno = XFS_B_TO_FSBT(mp, destoff); | |
1326 | sfsbno = XFS_B_TO_FSBT(mp, srcoff); | |
1327 | fsblen = XFS_B_TO_FSB(mp, len); | |
1328 | error = xfs_reflink_remap_blocks(src, sfsbno, dest, dfsbno, fsblen, | |
1329 | destoff + len); | |
1330 | if (error) | |
1331 | goto out_error; | |
1332 | ||
1333 | error = xfs_reflink_update_dest(dest, destoff + len); | |
1334 | if (error) | |
1335 | goto out_error; | |
1336 | ||
1337 | out_error: | |
1338 | xfs_iunlock(src, XFS_MMAPLOCK_EXCL); | |
1339 | xfs_iunlock(src, XFS_IOLOCK_EXCL); | |
1340 | if (src->i_ino != dest->i_ino) { | |
1341 | xfs_iunlock(dest, XFS_MMAPLOCK_EXCL); | |
1342 | xfs_iunlock(dest, XFS_IOLOCK_EXCL); | |
1343 | } | |
1344 | if (error) | |
1345 | trace_xfs_reflink_remap_range_error(dest, error, _RET_IP_); | |
1346 | return error; | |
1347 | } | |
98cc2db5 DW |
1348 | |
1349 | /* | |
1350 | * The user wants to preemptively CoW all shared blocks in this file, | |
1351 | * which enables us to turn off the reflink flag. Iterate all | |
1352 | * extents which are not prealloc/delalloc to see which ranges are | |
1353 | * mentioned in the refcount tree, then read those blocks into the | |
1354 | * pagecache, dirty them, fsync them back out, and then we can update | |
1355 | * the inode flag. What happens if we run out of memory? :) | |
1356 | */ | |
1357 | STATIC int | |
1358 | xfs_reflink_dirty_extents( | |
1359 | struct xfs_inode *ip, | |
1360 | xfs_fileoff_t fbno, | |
1361 | xfs_filblks_t end, | |
1362 | xfs_off_t isize) | |
1363 | { | |
1364 | struct xfs_mount *mp = ip->i_mount; | |
1365 | xfs_agnumber_t agno; | |
1366 | xfs_agblock_t agbno; | |
1367 | xfs_extlen_t aglen; | |
1368 | xfs_agblock_t rbno; | |
1369 | xfs_extlen_t rlen; | |
1370 | xfs_off_t fpos; | |
1371 | xfs_off_t flen; | |
1372 | struct xfs_bmbt_irec map[2]; | |
1373 | int nmaps; | |
1374 | int error; | |
1375 | ||
1376 | while (end - fbno > 0) { | |
1377 | nmaps = 1; | |
1378 | /* | |
1379 | * Look for extents in the file. Skip holes, delalloc, or | |
1380 | * unwritten extents; they can't be reflinked. | |
1381 | */ | |
1382 | error = xfs_bmapi_read(ip, fbno, end - fbno, map, &nmaps, 0); | |
1383 | if (error) | |
1384 | goto out; | |
1385 | if (nmaps == 0) | |
1386 | break; | |
1387 | if (map[0].br_startblock == HOLESTARTBLOCK || | |
1388 | map[0].br_startblock == DELAYSTARTBLOCK || | |
1389 | ISUNWRITTEN(&map[0])) | |
1390 | goto next; | |
1391 | ||
1392 | map[1] = map[0]; | |
1393 | while (map[1].br_blockcount) { | |
1394 | agno = XFS_FSB_TO_AGNO(mp, map[1].br_startblock); | |
1395 | agbno = XFS_FSB_TO_AGBNO(mp, map[1].br_startblock); | |
1396 | aglen = map[1].br_blockcount; | |
1397 | ||
1398 | error = xfs_reflink_find_shared(mp, agno, agbno, aglen, | |
1399 | &rbno, &rlen, true); | |
1400 | if (error) | |
1401 | goto out; | |
1402 | if (rbno == NULLAGBLOCK) | |
1403 | break; | |
1404 | ||
1405 | /* Dirty the pages */ | |
1406 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1407 | fpos = XFS_FSB_TO_B(mp, map[1].br_startoff + | |
1408 | (rbno - agbno)); | |
1409 | flen = XFS_FSB_TO_B(mp, rlen); | |
1410 | if (fpos + flen > isize) | |
1411 | flen = isize - fpos; | |
1412 | error = iomap_file_dirty(VFS_I(ip), fpos, flen, | |
1413 | &xfs_iomap_ops); | |
1414 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
1415 | if (error) | |
1416 | goto out; | |
1417 | ||
1418 | map[1].br_blockcount -= (rbno - agbno + rlen); | |
1419 | map[1].br_startoff += (rbno - agbno + rlen); | |
1420 | map[1].br_startblock += (rbno - agbno + rlen); | |
1421 | } | |
1422 | ||
1423 | next: | |
1424 | fbno = map[0].br_startoff + map[0].br_blockcount; | |
1425 | } | |
1426 | out: | |
1427 | return error; | |
1428 | } | |
1429 | ||
1430 | /* Clear the inode reflink flag if there are no shared extents. */ | |
1431 | int | |
1432 | xfs_reflink_clear_inode_flag( | |
1433 | struct xfs_inode *ip, | |
1434 | struct xfs_trans **tpp) | |
1435 | { | |
1436 | struct xfs_mount *mp = ip->i_mount; | |
1437 | xfs_fileoff_t fbno; | |
1438 | xfs_filblks_t end; | |
1439 | xfs_agnumber_t agno; | |
1440 | xfs_agblock_t agbno; | |
1441 | xfs_extlen_t aglen; | |
1442 | xfs_agblock_t rbno; | |
1443 | xfs_extlen_t rlen; | |
1444 | struct xfs_bmbt_irec map[2]; | |
1445 | int nmaps; | |
1446 | int error = 0; | |
1447 | ||
1448 | if (!(ip->i_d.di_flags2 & XFS_DIFLAG2_REFLINK)) | |
1449 | return 0; | |
1450 | ||
1451 | fbno = 0; | |
1452 | end = XFS_B_TO_FSB(mp, i_size_read(VFS_I(ip))); | |
1453 | while (end - fbno > 0) { | |
1454 | nmaps = 1; | |
1455 | /* | |
1456 | * Look for extents in the file. Skip holes, delalloc, or | |
1457 | * unwritten extents; they can't be reflinked. | |
1458 | */ | |
1459 | error = xfs_bmapi_read(ip, fbno, end - fbno, map, &nmaps, 0); | |
1460 | if (error) | |
1461 | return error; | |
1462 | if (nmaps == 0) | |
1463 | break; | |
1464 | if (map[0].br_startblock == HOLESTARTBLOCK || | |
1465 | map[0].br_startblock == DELAYSTARTBLOCK || | |
1466 | ISUNWRITTEN(&map[0])) | |
1467 | goto next; | |
1468 | ||
1469 | map[1] = map[0]; | |
1470 | while (map[1].br_blockcount) { | |
1471 | agno = XFS_FSB_TO_AGNO(mp, map[1].br_startblock); | |
1472 | agbno = XFS_FSB_TO_AGBNO(mp, map[1].br_startblock); | |
1473 | aglen = map[1].br_blockcount; | |
1474 | ||
1475 | error = xfs_reflink_find_shared(mp, agno, agbno, aglen, | |
1476 | &rbno, &rlen, false); | |
1477 | if (error) | |
1478 | return error; | |
1479 | /* Is there still a shared block here? */ | |
1480 | if (rbno != NULLAGBLOCK) | |
1481 | return 0; | |
1482 | ||
1483 | map[1].br_blockcount -= aglen; | |
1484 | map[1].br_startoff += aglen; | |
1485 | map[1].br_startblock += aglen; | |
1486 | } | |
1487 | ||
1488 | next: | |
1489 | fbno = map[0].br_startoff + map[0].br_blockcount; | |
1490 | } | |
1491 | ||
1492 | /* | |
1493 | * We didn't find any shared blocks so turn off the reflink flag. | |
1494 | * First, get rid of any leftover CoW mappings. | |
1495 | */ | |
1496 | error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, NULLFILEOFF); | |
1497 | if (error) | |
1498 | return error; | |
1499 | ||
1500 | /* Clear the inode flag. */ | |
1501 | trace_xfs_reflink_unset_inode_flag(ip); | |
1502 | ip->i_d.di_flags2 &= ~XFS_DIFLAG2_REFLINK; | |
1503 | xfs_trans_ijoin(*tpp, ip, 0); | |
1504 | xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE); | |
1505 | ||
1506 | return error; | |
1507 | } | |
1508 | ||
1509 | /* | |
1510 | * Clear the inode reflink flag if there are no shared extents and the size | |
1511 | * hasn't changed. | |
1512 | */ | |
1513 | STATIC int | |
1514 | xfs_reflink_try_clear_inode_flag( | |
1515 | struct xfs_inode *ip, | |
1516 | xfs_off_t old_isize) | |
1517 | { | |
1518 | struct xfs_mount *mp = ip->i_mount; | |
1519 | struct xfs_trans *tp; | |
1520 | int error = 0; | |
1521 | ||
1522 | /* Start a rolling transaction to remove the mappings */ | |
1523 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp); | |
1524 | if (error) | |
1525 | return error; | |
1526 | ||
1527 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
1528 | xfs_trans_ijoin(tp, ip, 0); | |
1529 | ||
1530 | if (old_isize != i_size_read(VFS_I(ip))) | |
1531 | goto cancel; | |
1532 | ||
1533 | error = xfs_reflink_clear_inode_flag(ip, &tp); | |
1534 | if (error) | |
1535 | goto cancel; | |
1536 | ||
1537 | error = xfs_trans_commit(tp); | |
1538 | if (error) | |
1539 | goto out; | |
1540 | ||
1541 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1542 | return 0; | |
1543 | cancel: | |
1544 | xfs_trans_cancel(tp); | |
1545 | out: | |
1546 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1547 | return error; | |
1548 | } | |
1549 | ||
1550 | /* | |
1551 | * Pre-COW all shared blocks within a given byte range of a file and turn off | |
1552 | * the reflink flag if we unshare all of the file's blocks. | |
1553 | */ | |
1554 | int | |
1555 | xfs_reflink_unshare( | |
1556 | struct xfs_inode *ip, | |
1557 | xfs_off_t offset, | |
1558 | xfs_off_t len) | |
1559 | { | |
1560 | struct xfs_mount *mp = ip->i_mount; | |
1561 | xfs_fileoff_t fbno; | |
1562 | xfs_filblks_t end; | |
1563 | xfs_off_t isize; | |
1564 | int error; | |
1565 | ||
1566 | if (!xfs_is_reflink_inode(ip)) | |
1567 | return 0; | |
1568 | ||
1569 | trace_xfs_reflink_unshare(ip, offset, len); | |
1570 | ||
1571 | inode_dio_wait(VFS_I(ip)); | |
1572 | ||
1573 | /* Try to CoW the selected ranges */ | |
1574 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
1575 | fbno = XFS_B_TO_FSB(mp, offset); | |
1576 | isize = i_size_read(VFS_I(ip)); | |
1577 | end = XFS_B_TO_FSB(mp, offset + len); | |
1578 | error = xfs_reflink_dirty_extents(ip, fbno, end, isize); | |
1579 | if (error) | |
1580 | goto out_unlock; | |
1581 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1582 | ||
1583 | /* Wait for the IO to finish */ | |
1584 | error = filemap_write_and_wait(VFS_I(ip)->i_mapping); | |
1585 | if (error) | |
1586 | goto out; | |
1587 | ||
1588 | /* Turn off the reflink flag if we unshared the whole file */ | |
1589 | if (offset == 0 && len == isize) { | |
1590 | error = xfs_reflink_try_clear_inode_flag(ip, isize); | |
1591 | if (error) | |
1592 | goto out; | |
1593 | } | |
1594 | ||
1595 | return 0; | |
1596 | ||
1597 | out_unlock: | |
1598 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1599 | out: | |
1600 | trace_xfs_reflink_unshare_error(ip, error, _RET_IP_); | |
1601 | return error; | |
1602 | } |