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0b61f8a4 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
3993baeb DW |
2 | /* |
3 | * Copyright (C) 2016 Oracle. All Rights Reserved. | |
3993baeb | 4 | * Author: Darrick J. Wong <darrick.wong@oracle.com> |
3993baeb DW |
5 | */ |
6 | #include "xfs.h" | |
7 | #include "xfs_fs.h" | |
8 | #include "xfs_shared.h" | |
9 | #include "xfs_format.h" | |
10 | #include "xfs_log_format.h" | |
11 | #include "xfs_trans_resv.h" | |
12 | #include "xfs_mount.h" | |
13 | #include "xfs_defer.h" | |
3993baeb DW |
14 | #include "xfs_inode.h" |
15 | #include "xfs_trans.h" | |
3993baeb DW |
16 | #include "xfs_bmap.h" |
17 | #include "xfs_bmap_util.h" | |
3993baeb | 18 | #include "xfs_trace.h" |
3993baeb | 19 | #include "xfs_icache.h" |
174edb0e | 20 | #include "xfs_btree.h" |
3993baeb DW |
21 | #include "xfs_refcount_btree.h" |
22 | #include "xfs_refcount.h" | |
23 | #include "xfs_bmap_btree.h" | |
24 | #include "xfs_trans_space.h" | |
25 | #include "xfs_bit.h" | |
26 | #include "xfs_alloc.h" | |
3993baeb | 27 | #include "xfs_quota.h" |
3993baeb | 28 | #include "xfs_reflink.h" |
2a06705c | 29 | #include "xfs_iomap.h" |
9bbafc71 | 30 | #include "xfs_ag.h" |
6fa164b8 | 31 | #include "xfs_ag_resv.h" |
3993baeb DW |
32 | |
33 | /* | |
34 | * Copy on Write of Shared Blocks | |
35 | * | |
36 | * XFS must preserve "the usual" file semantics even when two files share | |
37 | * the same physical blocks. This means that a write to one file must not | |
38 | * alter the blocks in a different file; the way that we'll do that is | |
39 | * through the use of a copy-on-write mechanism. At a high level, that | |
40 | * means that when we want to write to a shared block, we allocate a new | |
41 | * block, write the data to the new block, and if that succeeds we map the | |
42 | * new block into the file. | |
43 | * | |
44 | * XFS provides a "delayed allocation" mechanism that defers the allocation | |
45 | * of disk blocks to dirty-but-not-yet-mapped file blocks as long as | |
46 | * possible. This reduces fragmentation by enabling the filesystem to ask | |
47 | * for bigger chunks less often, which is exactly what we want for CoW. | |
48 | * | |
49 | * The delalloc mechanism begins when the kernel wants to make a block | |
50 | * writable (write_begin or page_mkwrite). If the offset is not mapped, we | |
51 | * create a delalloc mapping, which is a regular in-core extent, but without | |
52 | * a real startblock. (For delalloc mappings, the startblock encodes both | |
53 | * a flag that this is a delalloc mapping, and a worst-case estimate of how | |
54 | * many blocks might be required to put the mapping into the BMBT.) delalloc | |
55 | * mappings are a reservation against the free space in the filesystem; | |
56 | * adjacent mappings can also be combined into fewer larger mappings. | |
57 | * | |
5eda4300 DW |
58 | * As an optimization, the CoW extent size hint (cowextsz) creates |
59 | * outsized aligned delalloc reservations in the hope of landing out of | |
60 | * order nearby CoW writes in a single extent on disk, thereby reducing | |
61 | * fragmentation and improving future performance. | |
62 | * | |
63 | * D: --RRRRRRSSSRRRRRRRR--- (data fork) | |
64 | * C: ------DDDDDDD--------- (CoW fork) | |
65 | * | |
3993baeb | 66 | * When dirty pages are being written out (typically in writepage), the |
5eda4300 DW |
67 | * delalloc reservations are converted into unwritten mappings by |
68 | * allocating blocks and replacing the delalloc mapping with real ones. | |
69 | * A delalloc mapping can be replaced by several unwritten ones if the | |
70 | * free space is fragmented. | |
71 | * | |
72 | * D: --RRRRRRSSSRRRRRRRR--- | |
73 | * C: ------UUUUUUU--------- | |
3993baeb DW |
74 | * |
75 | * We want to adapt the delalloc mechanism for copy-on-write, since the | |
76 | * write paths are similar. The first two steps (creating the reservation | |
77 | * and allocating the blocks) are exactly the same as delalloc except that | |
78 | * the mappings must be stored in a separate CoW fork because we do not want | |
79 | * to disturb the mapping in the data fork until we're sure that the write | |
80 | * succeeded. IO completion in this case is the process of removing the old | |
81 | * mapping from the data fork and moving the new mapping from the CoW fork to | |
82 | * the data fork. This will be discussed shortly. | |
83 | * | |
84 | * For now, unaligned directio writes will be bounced back to the page cache. | |
85 | * Block-aligned directio writes will use the same mechanism as buffered | |
86 | * writes. | |
87 | * | |
5eda4300 DW |
88 | * Just prior to submitting the actual disk write requests, we convert |
89 | * the extents representing the range of the file actually being written | |
90 | * (as opposed to extra pieces created for the cowextsize hint) to real | |
91 | * extents. This will become important in the next step: | |
92 | * | |
93 | * D: --RRRRRRSSSRRRRRRRR--- | |
94 | * C: ------UUrrUUU--------- | |
95 | * | |
3993baeb DW |
96 | * CoW remapping must be done after the data block write completes, |
97 | * because we don't want to destroy the old data fork map until we're sure | |
98 | * the new block has been written. Since the new mappings are kept in a | |
99 | * separate fork, we can simply iterate these mappings to find the ones | |
100 | * that cover the file blocks that we just CoW'd. For each extent, simply | |
101 | * unmap the corresponding range in the data fork, map the new range into | |
5eda4300 DW |
102 | * the data fork, and remove the extent from the CoW fork. Because of |
103 | * the presence of the cowextsize hint, however, we must be careful | |
104 | * only to remap the blocks that we've actually written out -- we must | |
105 | * never remap delalloc reservations nor CoW staging blocks that have | |
106 | * yet to be written. This corresponds exactly to the real extents in | |
107 | * the CoW fork: | |
108 | * | |
109 | * D: --RRRRRRrrSRRRRRRRR--- | |
110 | * C: ------UU--UUU--------- | |
3993baeb DW |
111 | * |
112 | * Since the remapping operation can be applied to an arbitrary file | |
113 | * range, we record the need for the remap step as a flag in the ioend | |
114 | * instead of declaring a new IO type. This is required for direct io | |
115 | * because we only have ioend for the whole dio, and we have to be able to | |
116 | * remember the presence of unwritten blocks and CoW blocks with a single | |
117 | * ioend structure. Better yet, the more ground we can cover with one | |
118 | * ioend, the better. | |
119 | */ | |
2a06705c DW |
120 | |
121 | /* | |
122 | * Given an AG extent, find the lowest-numbered run of shared blocks | |
123 | * within that range and return the range in fbno/flen. If | |
124 | * find_end_of_shared is true, return the longest contiguous extent of | |
125 | * shared blocks. If there are no shared extents, fbno and flen will | |
126 | * be set to NULLAGBLOCK and 0, respectively. | |
127 | */ | |
08d3e84f | 128 | static int |
2a06705c | 129 | xfs_reflink_find_shared( |
08d3e84f | 130 | struct xfs_perag *pag, |
92ff7285 | 131 | struct xfs_trans *tp, |
2a06705c DW |
132 | xfs_agblock_t agbno, |
133 | xfs_extlen_t aglen, | |
134 | xfs_agblock_t *fbno, | |
135 | xfs_extlen_t *flen, | |
136 | bool find_end_of_shared) | |
137 | { | |
138 | struct xfs_buf *agbp; | |
139 | struct xfs_btree_cur *cur; | |
140 | int error; | |
141 | ||
08d3e84f | 142 | error = xfs_alloc_read_agf(pag, tp, 0, &agbp); |
2a06705c DW |
143 | if (error) |
144 | return error; | |
145 | ||
08d3e84f | 146 | cur = xfs_refcountbt_init_cursor(pag->pag_mount, tp, agbp, pag); |
2a06705c DW |
147 | |
148 | error = xfs_refcount_find_shared(cur, agbno, aglen, fbno, flen, | |
149 | find_end_of_shared); | |
150 | ||
0b04b6b8 | 151 | xfs_btree_del_cursor(cur, error); |
2a06705c | 152 | |
92ff7285 | 153 | xfs_trans_brelse(tp, agbp); |
2a06705c DW |
154 | return error; |
155 | } | |
156 | ||
157 | /* | |
158 | * Trim the mapping to the next block where there's a change in the | |
159 | * shared/unshared status. More specifically, this means that we | |
160 | * find the lowest-numbered extent of shared blocks that coincides with | |
161 | * the given block mapping. If the shared extent overlaps the start of | |
162 | * the mapping, trim the mapping to the end of the shared extent. If | |
163 | * the shared region intersects the mapping, trim the mapping to the | |
164 | * start of the shared extent. If there are no shared regions that | |
165 | * overlap, just return the original extent. | |
166 | */ | |
167 | int | |
168 | xfs_reflink_trim_around_shared( | |
169 | struct xfs_inode *ip, | |
170 | struct xfs_bmbt_irec *irec, | |
d392bc81 | 171 | bool *shared) |
2a06705c | 172 | { |
08d3e84f DC |
173 | struct xfs_mount *mp = ip->i_mount; |
174 | struct xfs_perag *pag; | |
2a06705c DW |
175 | xfs_agblock_t agbno; |
176 | xfs_extlen_t aglen; | |
177 | xfs_agblock_t fbno; | |
178 | xfs_extlen_t flen; | |
179 | int error = 0; | |
180 | ||
181 | /* Holes, unwritten, and delalloc extents cannot be shared */ | |
877f58f5 | 182 | if (!xfs_is_cow_inode(ip) || !xfs_bmap_is_written_extent(irec)) { |
2a06705c DW |
183 | *shared = false; |
184 | return 0; | |
185 | } | |
186 | ||
187 | trace_xfs_reflink_trim_around_shared(ip, irec); | |
188 | ||
08d3e84f DC |
189 | pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, irec->br_startblock)); |
190 | agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock); | |
2a06705c DW |
191 | aglen = irec->br_blockcount; |
192 | ||
08d3e84f DC |
193 | error = xfs_reflink_find_shared(pag, NULL, agbno, aglen, &fbno, &flen, |
194 | true); | |
195 | xfs_perag_put(pag); | |
2a06705c DW |
196 | if (error) |
197 | return error; | |
198 | ||
d392bc81 | 199 | *shared = false; |
2a06705c DW |
200 | if (fbno == NULLAGBLOCK) { |
201 | /* No shared blocks at all. */ | |
202 | return 0; | |
a0ebf8c4 ZH |
203 | } |
204 | ||
205 | if (fbno == agbno) { | |
2a06705c DW |
206 | /* |
207 | * The start of this extent is shared. Truncate the | |
208 | * mapping at the end of the shared region so that a | |
209 | * subsequent iteration starts at the start of the | |
210 | * unshared region. | |
211 | */ | |
212 | irec->br_blockcount = flen; | |
213 | *shared = true; | |
2a06705c | 214 | return 0; |
2a06705c | 215 | } |
a0ebf8c4 ZH |
216 | |
217 | /* | |
218 | * There's a shared extent midway through this extent. | |
219 | * Truncate the mapping at the start of the shared | |
220 | * extent so that a subsequent iteration starts at the | |
221 | * start of the shared region. | |
222 | */ | |
223 | irec->br_blockcount = fbno - agbno; | |
224 | return 0; | |
2a06705c DW |
225 | } |
226 | ||
aa124436 | 227 | int |
228 | xfs_bmap_trim_cow( | |
66ae56a5 CH |
229 | struct xfs_inode *ip, |
230 | struct xfs_bmbt_irec *imap, | |
231 | bool *shared) | |
232 | { | |
233 | /* We can't update any real extents in always COW mode. */ | |
234 | if (xfs_is_always_cow_inode(ip) && | |
235 | !isnullstartblock(imap->br_startblock)) { | |
236 | *shared = true; | |
237 | return 0; | |
238 | } | |
239 | ||
240 | /* Trim the mapping to the nearest shared extent boundary. */ | |
241 | return xfs_reflink_trim_around_shared(ip, imap, shared); | |
242 | } | |
243 | ||
26b91c72 CH |
244 | static int |
245 | xfs_reflink_convert_cow_locked( | |
246 | struct xfs_inode *ip, | |
247 | xfs_fileoff_t offset_fsb, | |
248 | xfs_filblks_t count_fsb) | |
5eda4300 | 249 | { |
26b91c72 CH |
250 | struct xfs_iext_cursor icur; |
251 | struct xfs_bmbt_irec got; | |
252 | struct xfs_btree_cur *dummy_cur = NULL; | |
253 | int dummy_logflags; | |
c1a4447f | 254 | int error = 0; |
5eda4300 | 255 | |
26b91c72 | 256 | if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, &got)) |
5eda4300 DW |
257 | return 0; |
258 | ||
26b91c72 CH |
259 | do { |
260 | if (got.br_startoff >= offset_fsb + count_fsb) | |
261 | break; | |
262 | if (got.br_state == XFS_EXT_NORM) | |
263 | continue; | |
264 | if (WARN_ON_ONCE(isnullstartblock(got.br_startblock))) | |
265 | return -EIO; | |
266 | ||
267 | xfs_trim_extent(&got, offset_fsb, count_fsb); | |
268 | if (!got.br_blockcount) | |
269 | continue; | |
270 | ||
271 | got.br_state = XFS_EXT_NORM; | |
272 | error = xfs_bmap_add_extent_unwritten_real(NULL, ip, | |
273 | XFS_COW_FORK, &icur, &dummy_cur, &got, | |
274 | &dummy_logflags); | |
275 | if (error) | |
276 | return error; | |
277 | } while (xfs_iext_next_extent(ip->i_cowfp, &icur, &got)); | |
278 | ||
279 | return error; | |
5eda4300 DW |
280 | } |
281 | ||
282 | /* Convert all of the unwritten CoW extents in a file's range to real ones. */ | |
283 | int | |
284 | xfs_reflink_convert_cow( | |
285 | struct xfs_inode *ip, | |
286 | xfs_off_t offset, | |
287 | xfs_off_t count) | |
288 | { | |
5eda4300 | 289 | struct xfs_mount *mp = ip->i_mount; |
5eda4300 DW |
290 | xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset); |
291 | xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count); | |
b121459c | 292 | xfs_filblks_t count_fsb = end_fsb - offset_fsb; |
26b91c72 | 293 | int error; |
5eda4300 | 294 | |
b121459c | 295 | ASSERT(count != 0); |
5eda4300 | 296 | |
b121459c | 297 | xfs_ilock(ip, XFS_ILOCK_EXCL); |
26b91c72 | 298 | error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb); |
5eda4300 DW |
299 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
300 | return error; | |
301 | } | |
302 | ||
df307077 DC |
303 | /* |
304 | * Find the extent that maps the given range in the COW fork. Even if the extent | |
305 | * is not shared we might have a preallocation for it in the COW fork. If so we | |
306 | * use it that rather than trigger a new allocation. | |
307 | */ | |
308 | static int | |
309 | xfs_find_trim_cow_extent( | |
310 | struct xfs_inode *ip, | |
311 | struct xfs_bmbt_irec *imap, | |
ffb375a8 | 312 | struct xfs_bmbt_irec *cmap, |
df307077 DC |
313 | bool *shared, |
314 | bool *found) | |
315 | { | |
316 | xfs_fileoff_t offset_fsb = imap->br_startoff; | |
317 | xfs_filblks_t count_fsb = imap->br_blockcount; | |
318 | struct xfs_iext_cursor icur; | |
df307077 DC |
319 | |
320 | *found = false; | |
321 | ||
322 | /* | |
323 | * If we don't find an overlapping extent, trim the range we need to | |
324 | * allocate to fit the hole we found. | |
325 | */ | |
ffb375a8 CH |
326 | if (!xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, cmap)) |
327 | cmap->br_startoff = offset_fsb + count_fsb; | |
328 | if (cmap->br_startoff > offset_fsb) { | |
032dc923 | 329 | xfs_trim_extent(imap, imap->br_startoff, |
ffb375a8 | 330 | cmap->br_startoff - imap->br_startoff); |
aa124436 | 331 | return xfs_bmap_trim_cow(ip, imap, shared); |
032dc923 | 332 | } |
df307077 DC |
333 | |
334 | *shared = true; | |
ffb375a8 CH |
335 | if (isnullstartblock(cmap->br_startblock)) { |
336 | xfs_trim_extent(imap, cmap->br_startoff, cmap->br_blockcount); | |
df307077 DC |
337 | return 0; |
338 | } | |
339 | ||
340 | /* real extent found - no need to allocate */ | |
ffb375a8 | 341 | xfs_trim_extent(cmap, offset_fsb, count_fsb); |
df307077 DC |
342 | *found = true; |
343 | return 0; | |
344 | } | |
345 | ||
d6211330 CB |
346 | static int |
347 | xfs_reflink_convert_unwritten( | |
348 | struct xfs_inode *ip, | |
349 | struct xfs_bmbt_irec *imap, | |
350 | struct xfs_bmbt_irec *cmap, | |
351 | bool convert_now) | |
352 | { | |
353 | xfs_fileoff_t offset_fsb = imap->br_startoff; | |
354 | xfs_filblks_t count_fsb = imap->br_blockcount; | |
355 | int error; | |
356 | ||
357 | /* | |
358 | * cmap might larger than imap due to cowextsize hint. | |
359 | */ | |
360 | xfs_trim_extent(cmap, offset_fsb, count_fsb); | |
361 | ||
362 | /* | |
363 | * COW fork extents are supposed to remain unwritten until we're ready | |
364 | * to initiate a disk write. For direct I/O we are going to write the | |
365 | * data and need the conversion, but for buffered writes we're done. | |
366 | */ | |
367 | if (!convert_now || cmap->br_state == XFS_EXT_NORM) | |
368 | return 0; | |
369 | ||
370 | trace_xfs_reflink_convert_cow(ip, cmap); | |
371 | ||
372 | error = xfs_reflink_convert_cow_locked(ip, offset_fsb, count_fsb); | |
373 | if (!error) | |
374 | cmap->br_state = XFS_EXT_NORM; | |
375 | ||
376 | return error; | |
377 | } | |
378 | ||
379 | static int | |
380 | xfs_reflink_fill_cow_hole( | |
0613f16c | 381 | struct xfs_inode *ip, |
3c68d44a | 382 | struct xfs_bmbt_irec *imap, |
ffb375a8 | 383 | struct xfs_bmbt_irec *cmap, |
3c68d44a | 384 | bool *shared, |
78f0cc9d | 385 | uint *lockmode, |
affe250a | 386 | bool convert_now) |
0613f16c DW |
387 | { |
388 | struct xfs_mount *mp = ip->i_mount; | |
df307077 | 389 | struct xfs_trans *tp; |
a14234c7 | 390 | xfs_filblks_t resaligned; |
d6211330 CB |
391 | xfs_extlen_t resblks; |
392 | int nimaps; | |
393 | int error; | |
394 | bool found; | |
3c68d44a | 395 | |
df307077 DC |
396 | resaligned = xfs_aligned_fsb_count(imap->br_startoff, |
397 | imap->br_blockcount, xfs_get_cowextsz_hint(ip)); | |
398 | resblks = XFS_DIOSTRAT_SPACE_RES(mp, resaligned); | |
a14234c7 | 399 | |
df307077 | 400 | xfs_iunlock(ip, *lockmode); |
f273387b | 401 | *lockmode = 0; |
3ba020be | 402 | |
f273387b DW |
403 | error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, resblks, 0, |
404 | false, &tp); | |
df307077 DC |
405 | if (error) |
406 | return error; | |
a14234c7 | 407 | |
f273387b | 408 | *lockmode = XFS_ILOCK_EXCL; |
3c68d44a | 409 | |
ffb375a8 | 410 | error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found); |
df307077 DC |
411 | if (error || !*shared) |
412 | goto out_trans_cancel; | |
d6211330 | 413 | |
df307077 DC |
414 | if (found) { |
415 | xfs_trans_cancel(tp); | |
416 | goto convert; | |
a14234c7 CH |
417 | } |
418 | ||
5eda4300 | 419 | /* Allocate the entire reservation as unwritten blocks. */ |
df307077 | 420 | nimaps = 1; |
3c68d44a | 421 | error = xfs_bmapi_write(tp, ip, imap->br_startoff, imap->br_blockcount, |
da781e64 BF |
422 | XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0, cmap, |
423 | &nimaps); | |
0613f16c | 424 | if (error) |
35b11010 | 425 | goto out_trans_cancel; |
0613f16c | 426 | |
86d692bf | 427 | xfs_inode_set_cowblocks_tag(ip); |
0613f16c | 428 | error = xfs_trans_commit(tp); |
a14234c7 | 429 | if (error) |
3c68d44a | 430 | return error; |
9f37bd11 DW |
431 | |
432 | /* | |
433 | * Allocation succeeded but the requested range was not even partially | |
434 | * satisfied? Bail out! | |
435 | */ | |
436 | if (nimaps == 0) | |
437 | return -ENOSPC; | |
d6211330 | 438 | |
3c68d44a | 439 | convert: |
d6211330 CB |
440 | return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now); |
441 | ||
442 | out_trans_cancel: | |
443 | xfs_trans_cancel(tp); | |
1a39ae41 | 444 | return error; |
d6211330 CB |
445 | } |
446 | ||
447 | static int | |
448 | xfs_reflink_fill_delalloc( | |
449 | struct xfs_inode *ip, | |
450 | struct xfs_bmbt_irec *imap, | |
451 | struct xfs_bmbt_irec *cmap, | |
452 | bool *shared, | |
453 | uint *lockmode, | |
454 | bool convert_now) | |
455 | { | |
456 | struct xfs_mount *mp = ip->i_mount; | |
457 | struct xfs_trans *tp; | |
458 | int nimaps; | |
459 | int error; | |
460 | bool found; | |
461 | ||
462 | do { | |
463 | xfs_iunlock(ip, *lockmode); | |
464 | *lockmode = 0; | |
465 | ||
466 | error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, 0, 0, | |
467 | false, &tp); | |
468 | if (error) | |
469 | return error; | |
470 | ||
471 | *lockmode = XFS_ILOCK_EXCL; | |
472 | ||
473 | error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, | |
474 | &found); | |
475 | if (error || !*shared) | |
476 | goto out_trans_cancel; | |
477 | ||
478 | if (found) { | |
479 | xfs_trans_cancel(tp); | |
480 | break; | |
481 | } | |
482 | ||
483 | ASSERT(isnullstartblock(cmap->br_startblock) || | |
484 | cmap->br_startblock == DELAYSTARTBLOCK); | |
485 | ||
486 | /* | |
487 | * Replace delalloc reservation with an unwritten extent. | |
488 | */ | |
489 | nimaps = 1; | |
490 | error = xfs_bmapi_write(tp, ip, cmap->br_startoff, | |
491 | cmap->br_blockcount, | |
492 | XFS_BMAPI_COWFORK | XFS_BMAPI_PREALLOC, 0, | |
493 | cmap, &nimaps); | |
494 | if (error) | |
495 | goto out_trans_cancel; | |
496 | ||
497 | xfs_inode_set_cowblocks_tag(ip); | |
498 | error = xfs_trans_commit(tp); | |
499 | if (error) | |
500 | return error; | |
501 | ||
502 | /* | |
503 | * Allocation succeeded but the requested range was not even | |
504 | * partially satisfied? Bail out! | |
505 | */ | |
506 | if (nimaps == 0) | |
507 | return -ENOSPC; | |
508 | } while (cmap->br_startoff + cmap->br_blockcount <= imap->br_startoff); | |
509 | ||
510 | return xfs_reflink_convert_unwritten(ip, imap, cmap, convert_now); | |
df307077 | 511 | |
df307077 DC |
512 | out_trans_cancel: |
513 | xfs_trans_cancel(tp); | |
3c68d44a | 514 | return error; |
0613f16c DW |
515 | } |
516 | ||
d6211330 CB |
517 | /* Allocate all CoW reservations covering a range of blocks in a file. */ |
518 | int | |
519 | xfs_reflink_allocate_cow( | |
520 | struct xfs_inode *ip, | |
521 | struct xfs_bmbt_irec *imap, | |
522 | struct xfs_bmbt_irec *cmap, | |
523 | bool *shared, | |
524 | uint *lockmode, | |
525 | bool convert_now) | |
526 | { | |
527 | int error; | |
528 | bool found; | |
529 | ||
530 | ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL)); | |
531 | if (!ip->i_cowfp) { | |
532 | ASSERT(!xfs_is_reflink_inode(ip)); | |
533 | xfs_ifork_init_cow(ip); | |
534 | } | |
535 | ||
536 | error = xfs_find_trim_cow_extent(ip, imap, cmap, shared, &found); | |
537 | if (error || !*shared) | |
538 | return error; | |
539 | ||
540 | /* CoW fork has a real extent */ | |
541 | if (found) | |
542 | return xfs_reflink_convert_unwritten(ip, imap, cmap, | |
543 | convert_now); | |
544 | ||
545 | /* | |
546 | * CoW fork does not have an extent and data extent is shared. | |
547 | * Allocate a real extent in the CoW fork. | |
548 | */ | |
549 | if (cmap->br_startoff > imap->br_startoff) | |
550 | return xfs_reflink_fill_cow_hole(ip, imap, cmap, shared, | |
551 | lockmode, convert_now); | |
552 | ||
553 | /* | |
554 | * CoW fork has a delalloc reservation. Replace it with a real extent. | |
555 | * There may or may not be a data fork mapping. | |
556 | */ | |
557 | if (isnullstartblock(cmap->br_startblock) || | |
558 | cmap->br_startblock == DELAYSTARTBLOCK) | |
559 | return xfs_reflink_fill_delalloc(ip, imap, cmap, shared, | |
560 | lockmode, convert_now); | |
561 | ||
562 | /* Shouldn't get here. */ | |
563 | ASSERT(0); | |
564 | return -EFSCORRUPTED; | |
565 | } | |
566 | ||
43caeb18 | 567 | /* |
3802a345 CH |
568 | * Cancel CoW reservations for some block range of an inode. |
569 | * | |
570 | * If cancel_real is true this function cancels all COW fork extents for the | |
571 | * inode; if cancel_real is false, real extents are not cleared. | |
c5295c6a DC |
572 | * |
573 | * Caller must have already joined the inode to the current transaction. The | |
574 | * inode will be joined to the transaction returned to the caller. | |
43caeb18 DW |
575 | */ |
576 | int | |
577 | xfs_reflink_cancel_cow_blocks( | |
578 | struct xfs_inode *ip, | |
579 | struct xfs_trans **tpp, | |
580 | xfs_fileoff_t offset_fsb, | |
3802a345 CH |
581 | xfs_fileoff_t end_fsb, |
582 | bool cancel_real) | |
43caeb18 | 583 | { |
732436ef | 584 | struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK); |
df5ab1b5 | 585 | struct xfs_bmbt_irec got, del; |
b2b1712a | 586 | struct xfs_iext_cursor icur; |
df5ab1b5 | 587 | int error = 0; |
43caeb18 | 588 | |
51d62690 | 589 | if (!xfs_inode_has_cow_data(ip)) |
43caeb18 | 590 | return 0; |
41caabd0 | 591 | if (!xfs_iext_lookup_extent_before(ip, ifp, &end_fsb, &icur, &got)) |
3e0ee78f | 592 | return 0; |
43caeb18 | 593 | |
41caabd0 CH |
594 | /* Walk backwards until we're out of the I/O range... */ |
595 | while (got.br_startoff + got.br_blockcount > offset_fsb) { | |
3e0ee78f CH |
596 | del = got; |
597 | xfs_trim_extent(&del, offset_fsb, end_fsb - offset_fsb); | |
41caabd0 CH |
598 | |
599 | /* Extent delete may have bumped ext forward */ | |
600 | if (!del.br_blockcount) { | |
601 | xfs_iext_prev(ifp, &icur); | |
602 | goto next_extent; | |
603 | } | |
604 | ||
3e0ee78f | 605 | trace_xfs_reflink_cancel_cow(ip, &del); |
43caeb18 | 606 | |
3e0ee78f CH |
607 | if (isnullstartblock(del.br_startblock)) { |
608 | error = xfs_bmap_del_extent_delay(ip, XFS_COW_FORK, | |
b2b1712a | 609 | &icur, &got, &del); |
43caeb18 DW |
610 | if (error) |
611 | break; | |
3802a345 | 612 | } else if (del.br_state == XFS_EXT_UNWRITTEN || cancel_real) { |
692b6cdd | 613 | ASSERT((*tpp)->t_highest_agno == NULLAGNUMBER); |
43caeb18 | 614 | |
174edb0e | 615 | /* Free the CoW orphan record. */ |
74b4c5d4 DW |
616 | xfs_refcount_free_cow_extent(*tpp, del.br_startblock, |
617 | del.br_blockcount); | |
174edb0e | 618 | |
7dfee17b | 619 | error = xfs_free_extent_later(*tpp, del.br_startblock, |
b742d7b4 DC |
620 | del.br_blockcount, NULL, |
621 | XFS_AG_RESV_NONE); | |
7dfee17b DC |
622 | if (error) |
623 | break; | |
43caeb18 | 624 | |
43caeb18 | 625 | /* Roll the transaction */ |
9e28a242 | 626 | error = xfs_defer_finish(tpp); |
9b1f4e98 | 627 | if (error) |
43caeb18 | 628 | break; |
43caeb18 DW |
629 | |
630 | /* Remove the mapping from the CoW fork. */ | |
b2b1712a | 631 | xfs_bmap_del_extent_cow(ip, &icur, &got, &del); |
4b4c1326 DW |
632 | |
633 | /* Remove the quota reservation */ | |
85546500 DW |
634 | error = xfs_quota_unreserve_blkres(ip, |
635 | del.br_blockcount); | |
4b4c1326 DW |
636 | if (error) |
637 | break; | |
9d40fba8 DW |
638 | } else { |
639 | /* Didn't do anything, push cursor back. */ | |
640 | xfs_iext_prev(ifp, &icur); | |
43caeb18 | 641 | } |
41caabd0 CH |
642 | next_extent: |
643 | if (!xfs_iext_get_extent(ifp, &icur, &got)) | |
c17a8ef4 | 644 | break; |
43caeb18 DW |
645 | } |
646 | ||
c17a8ef4 BF |
647 | /* clear tag if cow fork is emptied */ |
648 | if (!ifp->if_bytes) | |
649 | xfs_inode_clear_cowblocks_tag(ip); | |
43caeb18 DW |
650 | return error; |
651 | } | |
652 | ||
653 | /* | |
3802a345 CH |
654 | * Cancel CoW reservations for some byte range of an inode. |
655 | * | |
656 | * If cancel_real is true this function cancels all COW fork extents for the | |
657 | * inode; if cancel_real is false, real extents are not cleared. | |
43caeb18 DW |
658 | */ |
659 | int | |
660 | xfs_reflink_cancel_cow_range( | |
661 | struct xfs_inode *ip, | |
662 | xfs_off_t offset, | |
3802a345 CH |
663 | xfs_off_t count, |
664 | bool cancel_real) | |
43caeb18 DW |
665 | { |
666 | struct xfs_trans *tp; | |
667 | xfs_fileoff_t offset_fsb; | |
668 | xfs_fileoff_t end_fsb; | |
669 | int error; | |
670 | ||
671 | trace_xfs_reflink_cancel_cow_range(ip, offset, count); | |
66ae56a5 | 672 | ASSERT(ip->i_cowfp); |
43caeb18 DW |
673 | |
674 | offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); | |
675 | if (count == NULLFILEOFF) | |
676 | end_fsb = NULLFILEOFF; | |
677 | else | |
678 | end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); | |
679 | ||
680 | /* Start a rolling transaction to remove the mappings */ | |
681 | error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write, | |
73d30d48 | 682 | 0, 0, 0, &tp); |
43caeb18 DW |
683 | if (error) |
684 | goto out; | |
685 | ||
686 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
687 | xfs_trans_ijoin(tp, ip, 0); | |
688 | ||
689 | /* Scrape out the old CoW reservations */ | |
3802a345 CH |
690 | error = xfs_reflink_cancel_cow_blocks(ip, &tp, offset_fsb, end_fsb, |
691 | cancel_real); | |
43caeb18 DW |
692 | if (error) |
693 | goto out_cancel; | |
694 | ||
695 | error = xfs_trans_commit(tp); | |
696 | ||
697 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
698 | return error; | |
699 | ||
700 | out_cancel: | |
701 | xfs_trans_cancel(tp); | |
702 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
703 | out: | |
704 | trace_xfs_reflink_cancel_cow_range_error(ip, error, _RET_IP_); | |
705 | return error; | |
706 | } | |
707 | ||
708 | /* | |
d6f215f3 DW |
709 | * Remap part of the CoW fork into the data fork. |
710 | * | |
711 | * We aim to remap the range starting at @offset_fsb and ending at @end_fsb | |
712 | * into the data fork; this function will remap what it can (at the end of the | |
713 | * range) and update @end_fsb appropriately. Each remap gets its own | |
714 | * transaction because we can end up merging and splitting bmbt blocks for | |
715 | * every remap operation and we'd like to keep the block reservation | |
716 | * requirements as low as possible. | |
43caeb18 | 717 | */ |
d6f215f3 DW |
718 | STATIC int |
719 | xfs_reflink_end_cow_extent( | |
720 | struct xfs_inode *ip, | |
df2fd88f DW |
721 | xfs_fileoff_t *offset_fsb, |
722 | xfs_fileoff_t end_fsb) | |
43caeb18 | 723 | { |
d6f215f3 | 724 | struct xfs_iext_cursor icur; |
df2fd88f | 725 | struct xfs_bmbt_irec got, del, data; |
d6f215f3 DW |
726 | struct xfs_mount *mp = ip->i_mount; |
727 | struct xfs_trans *tp; | |
732436ef | 728 | struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_COW_FORK); |
d6f215f3 | 729 | unsigned int resblks; |
df2fd88f | 730 | int nmaps; |
d6f215f3 | 731 | int error; |
43caeb18 | 732 | |
c1112b6e | 733 | /* No COW extents? That's easy! */ |
d6f215f3 | 734 | if (ifp->if_bytes == 0) { |
df2fd88f | 735 | *offset_fsb = end_fsb; |
c1112b6e | 736 | return 0; |
d6f215f3 | 737 | } |
c1112b6e | 738 | |
d6f215f3 DW |
739 | resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); |
740 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, resblks, 0, | |
73d30d48 | 741 | XFS_TRANS_RESERVE, &tp); |
d6f215f3 DW |
742 | if (error) |
743 | return error; | |
43caeb18 | 744 | |
fe0be23e | 745 | /* |
d6f215f3 DW |
746 | * Lock the inode. We have to ijoin without automatic unlock because |
747 | * the lead transaction is the refcountbt record deletion; the data | |
748 | * fork update follows as a deferred log item. | |
fe0be23e | 749 | */ |
43caeb18 DW |
750 | xfs_ilock(ip, XFS_ILOCK_EXCL); |
751 | xfs_trans_ijoin(tp, ip, 0); | |
752 | ||
5f1d5bbf CB |
753 | error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, |
754 | XFS_IEXT_REFLINK_END_COW_CNT); | |
4f86bb4b CB |
755 | if (error == -EFBIG) |
756 | error = xfs_iext_count_upgrade(tp, ip, | |
757 | XFS_IEXT_REFLINK_END_COW_CNT); | |
5f1d5bbf CB |
758 | if (error) |
759 | goto out_cancel; | |
760 | ||
dc56015f CH |
761 | /* |
762 | * In case of racing, overlapping AIO writes no COW extents might be | |
763 | * left by the time I/O completes for the loser of the race. In that | |
764 | * case we are done. | |
765 | */ | |
df2fd88f DW |
766 | if (!xfs_iext_lookup_extent(ip, ifp, *offset_fsb, &icur, &got) || |
767 | got.br_startoff >= end_fsb) { | |
768 | *offset_fsb = end_fsb; | |
dc56015f | 769 | goto out_cancel; |
d6f215f3 | 770 | } |
43caeb18 | 771 | |
d6f215f3 DW |
772 | /* |
773 | * Only remap real extents that contain data. With AIO, speculative | |
774 | * preallocations can leak into the range we are called upon, and we | |
df2fd88f DW |
775 | * need to skip them. Preserve @got for the eventual CoW fork |
776 | * deletion; from now on @del represents the mapping that we're | |
777 | * actually remapping. | |
d6f215f3 | 778 | */ |
df2fd88f DW |
779 | while (!xfs_bmap_is_written_extent(&got)) { |
780 | if (!xfs_iext_next_extent(ifp, &icur, &got) || | |
781 | got.br_startoff >= end_fsb) { | |
782 | *offset_fsb = end_fsb; | |
783 | goto out_cancel; | |
784 | } | |
d6f215f3 | 785 | } |
df2fd88f | 786 | del = got; |
55f669f3 | 787 | xfs_trim_extent(&del, *offset_fsb, end_fsb - *offset_fsb); |
43caeb18 | 788 | |
df2fd88f DW |
789 | /* Grab the corresponding mapping in the data fork. */ |
790 | nmaps = 1; | |
791 | error = xfs_bmapi_read(ip, del.br_startoff, del.br_blockcount, &data, | |
792 | &nmaps, 0); | |
d6f215f3 DW |
793 | if (error) |
794 | goto out_cancel; | |
174edb0e | 795 | |
df2fd88f DW |
796 | /* We can only remap the smaller of the two extent sizes. */ |
797 | data.br_blockcount = min(data.br_blockcount, del.br_blockcount); | |
798 | del.br_blockcount = data.br_blockcount; | |
799 | ||
800 | trace_xfs_reflink_cow_remap_from(ip, &del); | |
801 | trace_xfs_reflink_cow_remap_to(ip, &data); | |
802 | ||
803 | if (xfs_bmap_is_real_extent(&data)) { | |
804 | /* | |
805 | * If the extent we're remapping is backed by storage (written | |
806 | * or not), unmap the extent and drop its refcount. | |
807 | */ | |
808 | xfs_bmap_unmap_extent(tp, ip, &data); | |
809 | xfs_refcount_decrease_extent(tp, &data); | |
810 | xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, | |
811 | -data.br_blockcount); | |
812 | } else if (data.br_startblock == DELAYSTARTBLOCK) { | |
813 | int done; | |
814 | ||
815 | /* | |
816 | * If the extent we're remapping is a delalloc reservation, | |
817 | * we can use the regular bunmapi function to release the | |
818 | * incore state. Dropping the delalloc reservation takes care | |
819 | * of the quota reservation for us. | |
820 | */ | |
821 | error = xfs_bunmapi(NULL, ip, data.br_startoff, | |
822 | data.br_blockcount, 0, 1, &done); | |
823 | if (error) | |
824 | goto out_cancel; | |
825 | ASSERT(done); | |
826 | } | |
43caeb18 | 827 | |
d6f215f3 | 828 | /* Free the CoW orphan record. */ |
74b4c5d4 | 829 | xfs_refcount_free_cow_extent(tp, del.br_startblock, del.br_blockcount); |
43caeb18 | 830 | |
d6f215f3 | 831 | /* Map the new blocks into the data fork. */ |
3e08f42a | 832 | xfs_bmap_map_extent(tp, ip, &del); |
4b4c1326 | 833 | |
d6f215f3 DW |
834 | /* Charge this new data fork mapping to the on-disk quota. */ |
835 | xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_DELBCOUNT, | |
836 | (long)del.br_blockcount); | |
c1112b6e | 837 | |
d6f215f3 DW |
838 | /* Remove the mapping from the CoW fork. */ |
839 | xfs_bmap_del_extent_cow(ip, &icur, &got, &del); | |
43caeb18 DW |
840 | |
841 | error = xfs_trans_commit(tp); | |
842 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
843 | if (error) | |
d6f215f3 DW |
844 | return error; |
845 | ||
846 | /* Update the caller about how much progress we made. */ | |
df2fd88f | 847 | *offset_fsb = del.br_startoff + del.br_blockcount; |
43caeb18 DW |
848 | return 0; |
849 | ||
e12199f8 | 850 | out_cancel: |
43caeb18 DW |
851 | xfs_trans_cancel(tp); |
852 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
d6f215f3 DW |
853 | return error; |
854 | } | |
855 | ||
856 | /* | |
857 | * Remap parts of a file's data fork after a successful CoW. | |
858 | */ | |
859 | int | |
860 | xfs_reflink_end_cow( | |
861 | struct xfs_inode *ip, | |
862 | xfs_off_t offset, | |
863 | xfs_off_t count) | |
864 | { | |
865 | xfs_fileoff_t offset_fsb; | |
866 | xfs_fileoff_t end_fsb; | |
867 | int error = 0; | |
868 | ||
869 | trace_xfs_reflink_end_cow(ip, offset, count); | |
870 | ||
871 | offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); | |
872 | end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count); | |
873 | ||
874 | /* | |
df2fd88f | 875 | * Walk forwards until we've remapped the I/O range. The loop function |
d6f215f3 DW |
876 | * repeatedly cycles the ILOCK to allocate one transaction per remapped |
877 | * extent. | |
878 | * | |
b63da6c8 | 879 | * If we're being called by writeback then the pages will still |
d6f215f3 DW |
880 | * have PageWriteback set, which prevents races with reflink remapping |
881 | * and truncate. Reflink remapping prevents races with writeback by | |
882 | * taking the iolock and mmaplock before flushing the pages and | |
883 | * remapping, which means there won't be any further writeback or page | |
884 | * cache dirtying until the reflink completes. | |
885 | * | |
886 | * We should never have two threads issuing writeback for the same file | |
887 | * region. There are also have post-eof checks in the writeback | |
888 | * preparation code so that we don't bother writing out pages that are | |
889 | * about to be truncated. | |
890 | * | |
891 | * If we're being called as part of directio write completion, the dio | |
892 | * count is still elevated, which reflink and truncate will wait for. | |
893 | * Reflink remapping takes the iolock and mmaplock and waits for | |
894 | * pending dio to finish, which should prevent any directio until the | |
895 | * remap completes. Multiple concurrent directio writes to the same | |
896 | * region are handled by end_cow processing only occurring for the | |
897 | * threads which succeed; the outcome of multiple overlapping direct | |
898 | * writes is not well defined anyway. | |
899 | * | |
900 | * It's possible that a buffered write and a direct write could collide | |
901 | * here (the buffered write stumbles in after the dio flushes and | |
902 | * invalidates the page cache and immediately queues writeback), but we | |
903 | * have never supported this 100%. If either disk write succeeds the | |
904 | * blocks will be remapped. | |
905 | */ | |
906 | while (end_fsb > offset_fsb && !error) | |
df2fd88f | 907 | error = xfs_reflink_end_cow_extent(ip, &offset_fsb, end_fsb); |
d6f215f3 DW |
908 | |
909 | if (error) | |
910 | trace_xfs_reflink_end_cow_error(ip, error, _RET_IP_); | |
43caeb18 DW |
911 | return error; |
912 | } | |
174edb0e DW |
913 | |
914 | /* | |
7993f1a4 DW |
915 | * Free all CoW staging blocks that are still referenced by the ondisk refcount |
916 | * metadata. The ondisk metadata does not track which inode created the | |
917 | * staging extent, so callers must ensure that there are no cached inodes with | |
918 | * live CoW staging extents. | |
174edb0e DW |
919 | */ |
920 | int | |
921 | xfs_reflink_recover_cow( | |
922 | struct xfs_mount *mp) | |
923 | { | |
934933c3 | 924 | struct xfs_perag *pag; |
174edb0e DW |
925 | xfs_agnumber_t agno; |
926 | int error = 0; | |
927 | ||
38c26bfd | 928 | if (!xfs_has_reflink(mp)) |
174edb0e DW |
929 | return 0; |
930 | ||
934933c3 | 931 | for_each_perag(mp, agno, pag) { |
a81a0621 | 932 | error = xfs_refcount_recover_cow_leftovers(mp, pag); |
934933c3 | 933 | if (error) { |
c4d5660a | 934 | xfs_perag_rele(pag); |
174edb0e | 935 | break; |
934933c3 | 936 | } |
174edb0e DW |
937 | } |
938 | ||
939 | return error; | |
940 | } | |
862bb360 DW |
941 | |
942 | /* | |
943 | * Reflinking (Block) Ranges of Two Files Together | |
944 | * | |
945 | * First, ensure that the reflink flag is set on both inodes. The flag is an | |
946 | * optimization to avoid unnecessary refcount btree lookups in the write path. | |
947 | * | |
948 | * Now we can iteratively remap the range of extents (and holes) in src to the | |
949 | * corresponding ranges in dest. Let drange and srange denote the ranges of | |
950 | * logical blocks in dest and src touched by the reflink operation. | |
951 | * | |
952 | * While the length of drange is greater than zero, | |
953 | * - Read src's bmbt at the start of srange ("imap") | |
954 | * - If imap doesn't exist, make imap appear to start at the end of srange | |
955 | * with zero length. | |
956 | * - If imap starts before srange, advance imap to start at srange. | |
957 | * - If imap goes beyond srange, truncate imap to end at the end of srange. | |
958 | * - Punch (imap start - srange start + imap len) blocks from dest at | |
959 | * offset (drange start). | |
960 | * - If imap points to a real range of pblks, | |
961 | * > Increase the refcount of the imap's pblks | |
962 | * > Map imap's pblks into dest at the offset | |
963 | * (drange start + imap start - srange start) | |
964 | * - Advance drange and srange by (imap start - srange start + imap len) | |
965 | * | |
966 | * Finally, if the reflink made dest longer, update both the in-core and | |
967 | * on-disk file sizes. | |
968 | * | |
969 | * ASCII Art Demonstration: | |
970 | * | |
971 | * Let's say we want to reflink this source file: | |
972 | * | |
973 | * ----SSSSSSS-SSSSS----SSSSSS (src file) | |
974 | * <--------------------> | |
975 | * | |
976 | * into this destination file: | |
977 | * | |
978 | * --DDDDDDDDDDDDDDDDDDD--DDD (dest file) | |
979 | * <--------------------> | |
980 | * '-' means a hole, and 'S' and 'D' are written blocks in the src and dest. | |
981 | * Observe that the range has different logical offsets in either file. | |
982 | * | |
983 | * Consider that the first extent in the source file doesn't line up with our | |
984 | * reflink range. Unmapping and remapping are separate operations, so we can | |
985 | * unmap more blocks from the destination file than we remap. | |
986 | * | |
987 | * ----SSSSSSS-SSSSS----SSSSSS | |
988 | * <-------> | |
989 | * --DDDDD---------DDDDD--DDD | |
990 | * <-------> | |
991 | * | |
992 | * Now remap the source extent into the destination file: | |
993 | * | |
994 | * ----SSSSSSS-SSSSS----SSSSSS | |
995 | * <-------> | |
996 | * --DDDDD--SSSSSSSDDDDD--DDD | |
997 | * <-------> | |
998 | * | |
999 | * Do likewise with the second hole and extent in our range. Holes in the | |
1000 | * unmap range don't affect our operation. | |
1001 | * | |
1002 | * ----SSSSSSS-SSSSS----SSSSSS | |
1003 | * <----> | |
1004 | * --DDDDD--SSSSSSS-SSSSS-DDD | |
1005 | * <----> | |
1006 | * | |
1007 | * Finally, unmap and remap part of the third extent. This will increase the | |
1008 | * size of the destination file. | |
1009 | * | |
1010 | * ----SSSSSSS-SSSSS----SSSSSS | |
1011 | * <-----> | |
1012 | * --DDDDD--SSSSSSS-SSSSS----SSS | |
1013 | * <-----> | |
1014 | * | |
1015 | * Once we update the destination file's i_size, we're done. | |
1016 | */ | |
1017 | ||
1018 | /* | |
1019 | * Ensure the reflink bit is set in both inodes. | |
1020 | */ | |
1021 | STATIC int | |
1022 | xfs_reflink_set_inode_flag( | |
1023 | struct xfs_inode *src, | |
1024 | struct xfs_inode *dest) | |
1025 | { | |
1026 | struct xfs_mount *mp = src->i_mount; | |
1027 | int error; | |
1028 | struct xfs_trans *tp; | |
1029 | ||
1030 | if (xfs_is_reflink_inode(src) && xfs_is_reflink_inode(dest)) | |
1031 | return 0; | |
1032 | ||
1033 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); | |
1034 | if (error) | |
1035 | goto out_error; | |
1036 | ||
1037 | /* Lock both files against IO */ | |
1038 | if (src->i_ino == dest->i_ino) | |
1039 | xfs_ilock(src, XFS_ILOCK_EXCL); | |
1040 | else | |
7c2d238a | 1041 | xfs_lock_two_inodes(src, XFS_ILOCK_EXCL, dest, XFS_ILOCK_EXCL); |
862bb360 DW |
1042 | |
1043 | if (!xfs_is_reflink_inode(src)) { | |
1044 | trace_xfs_reflink_set_inode_flag(src); | |
1045 | xfs_trans_ijoin(tp, src, XFS_ILOCK_EXCL); | |
3e09ab8f | 1046 | src->i_diflags2 |= XFS_DIFLAG2_REFLINK; |
862bb360 DW |
1047 | xfs_trans_log_inode(tp, src, XFS_ILOG_CORE); |
1048 | xfs_ifork_init_cow(src); | |
1049 | } else | |
1050 | xfs_iunlock(src, XFS_ILOCK_EXCL); | |
1051 | ||
1052 | if (src->i_ino == dest->i_ino) | |
1053 | goto commit_flags; | |
1054 | ||
1055 | if (!xfs_is_reflink_inode(dest)) { | |
1056 | trace_xfs_reflink_set_inode_flag(dest); | |
1057 | xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL); | |
3e09ab8f | 1058 | dest->i_diflags2 |= XFS_DIFLAG2_REFLINK; |
862bb360 DW |
1059 | xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE); |
1060 | xfs_ifork_init_cow(dest); | |
1061 | } else | |
1062 | xfs_iunlock(dest, XFS_ILOCK_EXCL); | |
1063 | ||
1064 | commit_flags: | |
1065 | error = xfs_trans_commit(tp); | |
1066 | if (error) | |
1067 | goto out_error; | |
1068 | return error; | |
1069 | ||
1070 | out_error: | |
1071 | trace_xfs_reflink_set_inode_flag_error(dest, error, _RET_IP_); | |
1072 | return error; | |
1073 | } | |
1074 | ||
1075 | /* | |
f7ca3522 | 1076 | * Update destination inode size & cowextsize hint, if necessary. |
862bb360 | 1077 | */ |
3fc9f5e4 | 1078 | int |
862bb360 DW |
1079 | xfs_reflink_update_dest( |
1080 | struct xfs_inode *dest, | |
f7ca3522 | 1081 | xfs_off_t newlen, |
c5ecb423 | 1082 | xfs_extlen_t cowextsize, |
a91ae49b | 1083 | unsigned int remap_flags) |
862bb360 DW |
1084 | { |
1085 | struct xfs_mount *mp = dest->i_mount; | |
1086 | struct xfs_trans *tp; | |
1087 | int error; | |
1088 | ||
bf4a1fcf | 1089 | if (newlen <= i_size_read(VFS_I(dest)) && cowextsize == 0) |
862bb360 DW |
1090 | return 0; |
1091 | ||
1092 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp); | |
1093 | if (error) | |
1094 | goto out_error; | |
1095 | ||
1096 | xfs_ilock(dest, XFS_ILOCK_EXCL); | |
1097 | xfs_trans_ijoin(tp, dest, XFS_ILOCK_EXCL); | |
1098 | ||
f7ca3522 DW |
1099 | if (newlen > i_size_read(VFS_I(dest))) { |
1100 | trace_xfs_reflink_update_inode_size(dest, newlen); | |
1101 | i_size_write(VFS_I(dest), newlen); | |
13d2c10b | 1102 | dest->i_disk_size = newlen; |
f7ca3522 DW |
1103 | } |
1104 | ||
1105 | if (cowextsize) { | |
b33ce57d | 1106 | dest->i_cowextsize = cowextsize; |
3e09ab8f | 1107 | dest->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE; |
f7ca3522 DW |
1108 | } |
1109 | ||
862bb360 DW |
1110 | xfs_trans_log_inode(tp, dest, XFS_ILOG_CORE); |
1111 | ||
1112 | error = xfs_trans_commit(tp); | |
1113 | if (error) | |
1114 | goto out_error; | |
1115 | return error; | |
1116 | ||
1117 | out_error: | |
1118 | trace_xfs_reflink_update_inode_size_error(dest, error, _RET_IP_); | |
1119 | return error; | |
1120 | } | |
1121 | ||
6fa164b8 DW |
1122 | /* |
1123 | * Do we have enough reserve in this AG to handle a reflink? The refcount | |
1124 | * btree already reserved all the space it needs, but the rmap btree can grow | |
1125 | * infinitely, so we won't allow more reflinks when the AG is down to the | |
1126 | * btree reserves. | |
1127 | */ | |
1128 | static int | |
1129 | xfs_reflink_ag_has_free_space( | |
1130 | struct xfs_mount *mp, | |
1131 | xfs_agnumber_t agno) | |
1132 | { | |
1133 | struct xfs_perag *pag; | |
1134 | int error = 0; | |
1135 | ||
38c26bfd | 1136 | if (!xfs_has_rmapbt(mp)) |
6fa164b8 DW |
1137 | return 0; |
1138 | ||
1139 | pag = xfs_perag_get(mp, agno); | |
21592863 | 1140 | if (xfs_ag_resv_critical(pag, XFS_AG_RESV_RMAPBT) || |
6fa164b8 DW |
1141 | xfs_ag_resv_critical(pag, XFS_AG_RESV_METADATA)) |
1142 | error = -ENOSPC; | |
1143 | xfs_perag_put(pag); | |
1144 | return error; | |
1145 | } | |
1146 | ||
862bb360 | 1147 | /* |
00fd1d56 DW |
1148 | * Remap the given extent into the file. The dmap blockcount will be set to |
1149 | * the number of blocks that were actually remapped. | |
862bb360 DW |
1150 | */ |
1151 | STATIC int | |
1152 | xfs_reflink_remap_extent( | |
1153 | struct xfs_inode *ip, | |
00fd1d56 | 1154 | struct xfs_bmbt_irec *dmap, |
862bb360 DW |
1155 | xfs_off_t new_isize) |
1156 | { | |
00fd1d56 | 1157 | struct xfs_bmbt_irec smap; |
862bb360 DW |
1158 | struct xfs_mount *mp = ip->i_mount; |
1159 | struct xfs_trans *tp; | |
862bb360 | 1160 | xfs_off_t newlen; |
f273387b | 1161 | int64_t qdelta = 0; |
00fd1d56 | 1162 | unsigned int resblks; |
4ca74205 | 1163 | bool quota_reserved = true; |
00fd1d56 DW |
1164 | bool smap_real; |
1165 | bool dmap_written = xfs_bmap_is_written_extent(dmap); | |
ee898d78 | 1166 | int iext_delta = 0; |
00fd1d56 | 1167 | int nimaps; |
862bb360 DW |
1168 | int error; |
1169 | ||
f273387b DW |
1170 | /* |
1171 | * Start a rolling transaction to switch the mappings. | |
1172 | * | |
1173 | * Adding a written extent to the extent map can cause a bmbt split, | |
1174 | * and removing a mapped extent from the extent can cause a bmbt split. | |
1175 | * The two operations cannot both cause a split since they operate on | |
1176 | * the same index in the bmap btree, so we only need a reservation for | |
1177 | * one bmbt split if either thing is happening. However, we haven't | |
1178 | * locked the inode yet, so we reserve assuming this is the case. | |
4ca74205 DW |
1179 | * |
1180 | * The first allocation call tries to reserve enough space to handle | |
1181 | * mapping dmap into a sparse part of the file plus the bmbt split. We | |
1182 | * haven't locked the inode or read the existing mapping yet, so we do | |
1183 | * not know for sure that we need the space. This should succeed most | |
1184 | * of the time. | |
1185 | * | |
1186 | * If the first attempt fails, try again but reserving only enough | |
1187 | * space to handle a bmbt split. This is the hard minimum requirement, | |
1188 | * and we revisit quota reservations later when we know more about what | |
1189 | * we're remapping. | |
f273387b | 1190 | */ |
00fd1d56 | 1191 | resblks = XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK); |
4ca74205 DW |
1192 | error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, |
1193 | resblks + dmap->br_blockcount, 0, false, &tp); | |
1194 | if (error == -EDQUOT || error == -ENOSPC) { | |
1195 | quota_reserved = false; | |
1196 | error = xfs_trans_alloc_inode(ip, &M_RES(mp)->tr_write, | |
1197 | resblks, 0, false, &tp); | |
1198 | } | |
862bb360 DW |
1199 | if (error) |
1200 | goto out; | |
1201 | ||
83895227 | 1202 | /* |
00fd1d56 DW |
1203 | * Read what's currently mapped in the destination file into smap. |
1204 | * If smap isn't a hole, we will have to remove it before we can add | |
1205 | * dmap to the destination file. | |
83895227 | 1206 | */ |
00fd1d56 DW |
1207 | nimaps = 1; |
1208 | error = xfs_bmapi_read(ip, dmap->br_startoff, dmap->br_blockcount, | |
1209 | &smap, &nimaps, 0); | |
83895227 DW |
1210 | if (error) |
1211 | goto out_cancel; | |
00fd1d56 DW |
1212 | ASSERT(nimaps == 1 && smap.br_startoff == dmap->br_startoff); |
1213 | smap_real = xfs_bmap_is_real_extent(&smap); | |
862bb360 | 1214 | |
00fd1d56 DW |
1215 | /* |
1216 | * We can only remap as many blocks as the smaller of the two extent | |
1217 | * maps, because we can only remap one extent at a time. | |
1218 | */ | |
1219 | dmap->br_blockcount = min(dmap->br_blockcount, smap.br_blockcount); | |
1220 | ASSERT(dmap->br_blockcount == smap.br_blockcount); | |
862bb360 | 1221 | |
00fd1d56 DW |
1222 | trace_xfs_reflink_remap_extent_dest(ip, &smap); |
1223 | ||
168eae80 DW |
1224 | /* |
1225 | * Two extents mapped to the same physical block must not have | |
1226 | * different states; that's filesystem corruption. Move on to the next | |
1227 | * extent if they're both holes or both the same physical extent. | |
1228 | */ | |
1229 | if (dmap->br_startblock == smap.br_startblock) { | |
1230 | if (dmap->br_state != smap.br_state) | |
1231 | error = -EFSCORRUPTED; | |
1232 | goto out_cancel; | |
1233 | } | |
1234 | ||
1235 | /* If both extents are unwritten, leave them alone. */ | |
1236 | if (dmap->br_state == XFS_EXT_UNWRITTEN && | |
1237 | smap.br_state == XFS_EXT_UNWRITTEN) | |
1238 | goto out_cancel; | |
1239 | ||
00fd1d56 DW |
1240 | /* No reflinking if the AG of the dest mapping is low on space. */ |
1241 | if (dmap_written) { | |
1242 | error = xfs_reflink_ag_has_free_space(mp, | |
1243 | XFS_FSB_TO_AGNO(mp, dmap->br_startblock)); | |
862bb360 | 1244 | if (error) |
c8eac49e | 1245 | goto out_cancel; |
00fd1d56 | 1246 | } |
862bb360 | 1247 | |
00fd1d56 | 1248 | /* |
f273387b | 1249 | * Increase quota reservation if we think the quota block counter for |
00fd1d56 DW |
1250 | * this file could increase. |
1251 | * | |
00fd1d56 DW |
1252 | * If we are mapping a written extent into the file, we need to have |
1253 | * enough quota block count reservation to handle the blocks in that | |
94b941fd DW |
1254 | * extent. We log only the delta to the quota block counts, so if the |
1255 | * extent we're unmapping also has blocks allocated to it, we don't | |
1256 | * need a quota reservation for the extent itself. | |
00fd1d56 DW |
1257 | * |
1258 | * Note that if we're replacing a delalloc reservation with a written | |
1259 | * extent, we have to take the full quota reservation because removing | |
1260 | * the delalloc reservation gives the block count back to the quota | |
1261 | * count. This is suboptimal, but the VFS flushed the dest range | |
1262 | * before we started. That should have removed all the delalloc | |
1263 | * reservations, but we code defensively. | |
766aabd5 DW |
1264 | * |
1265 | * xfs_trans_alloc_inode above already tried to grab an even larger | |
1266 | * quota reservation, and kicked off a blockgc scan if it couldn't. | |
1267 | * If we can't get a potentially smaller quota reservation now, we're | |
1268 | * done. | |
00fd1d56 | 1269 | */ |
4ca74205 | 1270 | if (!quota_reserved && !smap_real && dmap_written) { |
f273387b DW |
1271 | error = xfs_trans_reserve_quota_nblks(tp, ip, |
1272 | dmap->br_blockcount, 0, false); | |
aa5d0ba0 DW |
1273 | if (error) |
1274 | goto out_cancel; | |
1275 | } | |
00fd1d56 | 1276 | |
ee898d78 CB |
1277 | if (smap_real) |
1278 | ++iext_delta; | |
1279 | ||
1280 | if (dmap_written) | |
1281 | ++iext_delta; | |
1282 | ||
1283 | error = xfs_iext_count_may_overflow(ip, XFS_DATA_FORK, iext_delta); | |
4f86bb4b CB |
1284 | if (error == -EFBIG) |
1285 | error = xfs_iext_count_upgrade(tp, ip, iext_delta); | |
ee898d78 CB |
1286 | if (error) |
1287 | goto out_cancel; | |
1288 | ||
00fd1d56 | 1289 | if (smap_real) { |
862bb360 | 1290 | /* |
00fd1d56 DW |
1291 | * If the extent we're unmapping is backed by storage (written |
1292 | * or not), unmap the extent and drop its refcount. | |
862bb360 | 1293 | */ |
00fd1d56 DW |
1294 | xfs_bmap_unmap_extent(tp, ip, &smap); |
1295 | xfs_refcount_decrease_extent(tp, &smap); | |
1296 | qdelta -= smap.br_blockcount; | |
1297 | } else if (smap.br_startblock == DELAYSTARTBLOCK) { | |
f1e6a8d7 | 1298 | int done; |
862bb360 | 1299 | |
00fd1d56 DW |
1300 | /* |
1301 | * If the extent we're unmapping is a delalloc reservation, | |
1302 | * we can use the regular bunmapi function to release the | |
1303 | * incore state. Dropping the delalloc reservation takes care | |
1304 | * of the quota reservation for us. | |
1305 | */ | |
f1e6a8d7 DW |
1306 | error = xfs_bunmapi(NULL, ip, smap.br_startoff, |
1307 | smap.br_blockcount, 0, 1, &done); | |
00fd1d56 DW |
1308 | if (error) |
1309 | goto out_cancel; | |
f1e6a8d7 | 1310 | ASSERT(done); |
00fd1d56 | 1311 | } |
862bb360 | 1312 | |
00fd1d56 DW |
1313 | /* |
1314 | * If the extent we're sharing is backed by written storage, increase | |
1315 | * its refcount and map it into the file. | |
1316 | */ | |
1317 | if (dmap_written) { | |
1318 | xfs_refcount_increase_extent(tp, dmap); | |
1319 | xfs_bmap_map_extent(tp, ip, dmap); | |
1320 | qdelta += dmap->br_blockcount; | |
1321 | } | |
862bb360 | 1322 | |
00fd1d56 | 1323 | xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, qdelta); |
862bb360 | 1324 | |
00fd1d56 DW |
1325 | /* Update dest isize if needed. */ |
1326 | newlen = XFS_FSB_TO_B(mp, dmap->br_startoff + dmap->br_blockcount); | |
1327 | newlen = min_t(xfs_off_t, newlen, new_isize); | |
1328 | if (newlen > i_size_read(VFS_I(ip))) { | |
1329 | trace_xfs_reflink_update_inode_size(ip, newlen); | |
1330 | i_size_write(VFS_I(ip), newlen); | |
13d2c10b | 1331 | ip->i_disk_size = newlen; |
00fd1d56 | 1332 | xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE); |
862bb360 DW |
1333 | } |
1334 | ||
00fd1d56 | 1335 | /* Commit everything and unlock. */ |
862bb360 | 1336 | error = xfs_trans_commit(tp); |
00fd1d56 | 1337 | goto out_unlock; |
862bb360 | 1338 | |
862bb360 DW |
1339 | out_cancel: |
1340 | xfs_trans_cancel(tp); | |
00fd1d56 | 1341 | out_unlock: |
862bb360 DW |
1342 | xfs_iunlock(ip, XFS_ILOCK_EXCL); |
1343 | out: | |
00fd1d56 DW |
1344 | if (error) |
1345 | trace_xfs_reflink_remap_extent_error(ip, error, _RET_IP_); | |
862bb360 DW |
1346 | return error; |
1347 | } | |
1348 | ||
00fd1d56 | 1349 | /* Remap a range of one file to the other. */ |
3fc9f5e4 | 1350 | int |
862bb360 DW |
1351 | xfs_reflink_remap_blocks( |
1352 | struct xfs_inode *src, | |
9f04aaff | 1353 | loff_t pos_in, |
862bb360 | 1354 | struct xfs_inode *dest, |
9f04aaff | 1355 | loff_t pos_out, |
3f68c1f5 DW |
1356 | loff_t remap_len, |
1357 | loff_t *remapped) | |
862bb360 DW |
1358 | { |
1359 | struct xfs_bmbt_irec imap; | |
00fd1d56 DW |
1360 | struct xfs_mount *mp = src->i_mount; |
1361 | xfs_fileoff_t srcoff = XFS_B_TO_FSBT(mp, pos_in); | |
1362 | xfs_fileoff_t destoff = XFS_B_TO_FSBT(mp, pos_out); | |
9f04aaff | 1363 | xfs_filblks_t len; |
3f68c1f5 | 1364 | xfs_filblks_t remapped_len = 0; |
9f04aaff | 1365 | xfs_off_t new_isize = pos_out + remap_len; |
862bb360 DW |
1366 | int nimaps; |
1367 | int error = 0; | |
9f04aaff | 1368 | |
00fd1d56 DW |
1369 | len = min_t(xfs_filblks_t, XFS_B_TO_FSB(mp, remap_len), |
1370 | XFS_MAX_FILEOFF); | |
862bb360 | 1371 | |
00fd1d56 | 1372 | trace_xfs_reflink_remap_blocks(src, srcoff, len, dest, destoff); |
01c2e13d | 1373 | |
00fd1d56 DW |
1374 | while (len > 0) { |
1375 | unsigned int lock_mode; | |
01c2e13d | 1376 | |
862bb360 DW |
1377 | /* Read extent from the source file */ |
1378 | nimaps = 1; | |
01c2e13d | 1379 | lock_mode = xfs_ilock_data_map_shared(src); |
862bb360 | 1380 | error = xfs_bmapi_read(src, srcoff, len, &imap, &nimaps, 0); |
01c2e13d | 1381 | xfs_iunlock(src, lock_mode); |
862bb360 | 1382 | if (error) |
9f04aaff | 1383 | break; |
00fd1d56 DW |
1384 | /* |
1385 | * The caller supposedly flushed all dirty pages in the source | |
1386 | * file range, which means that writeback should have allocated | |
1387 | * or deleted all delalloc reservations in that range. If we | |
1388 | * find one, that's a good sign that something is seriously | |
1389 | * wrong here. | |
1390 | */ | |
1391 | ASSERT(nimaps == 1 && imap.br_startoff == srcoff); | |
1392 | if (imap.br_startblock == DELAYSTARTBLOCK) { | |
1393 | ASSERT(imap.br_startblock != DELAYSTARTBLOCK); | |
1394 | error = -EFSCORRUPTED; | |
1395 | break; | |
1396 | } | |
862bb360 | 1397 | |
00fd1d56 | 1398 | trace_xfs_reflink_remap_extent_src(src, &imap); |
862bb360 | 1399 | |
00fd1d56 DW |
1400 | /* Remap into the destination file at the given offset. */ |
1401 | imap.br_startoff = destoff; | |
1402 | error = xfs_reflink_remap_extent(dest, &imap, new_isize); | |
862bb360 | 1403 | if (error) |
9f04aaff | 1404 | break; |
862bb360 DW |
1405 | |
1406 | if (fatal_signal_pending(current)) { | |
1407 | error = -EINTR; | |
9f04aaff | 1408 | break; |
862bb360 DW |
1409 | } |
1410 | ||
1411 | /* Advance drange/srange */ | |
00fd1d56 DW |
1412 | srcoff += imap.br_blockcount; |
1413 | destoff += imap.br_blockcount; | |
1414 | len -= imap.br_blockcount; | |
1415 | remapped_len += imap.br_blockcount; | |
862bb360 DW |
1416 | } |
1417 | ||
9f04aaff DW |
1418 | if (error) |
1419 | trace_xfs_reflink_remap_blocks_error(dest, error, _RET_IP_); | |
3f68c1f5 DW |
1420 | *remapped = min_t(loff_t, remap_len, |
1421 | XFS_FSB_TO_B(src->i_mount, remapped_len)); | |
862bb360 DW |
1422 | return error; |
1423 | } | |
1424 | ||
410fdc72 DW |
1425 | /* |
1426 | * If we're reflinking to a point past the destination file's EOF, we must | |
1427 | * zero any speculative post-EOF preallocations that sit between the old EOF | |
1428 | * and the destination file offset. | |
1429 | */ | |
1430 | static int | |
1431 | xfs_reflink_zero_posteof( | |
1432 | struct xfs_inode *ip, | |
1433 | loff_t pos) | |
1434 | { | |
1435 | loff_t isize = i_size_read(VFS_I(ip)); | |
1436 | ||
1437 | if (pos <= isize) | |
1438 | return 0; | |
1439 | ||
1440 | trace_xfs_zero_eof(ip, isize, pos - isize); | |
f1ba5faf | 1441 | return xfs_zero_range(ip, isize, pos - isize, NULL); |
410fdc72 DW |
1442 | } |
1443 | ||
862bb360 | 1444 | /* |
0d41e1d2 | 1445 | * Prepare two files for range cloning. Upon a successful return both inodes |
b3998900 DC |
1446 | * will have the iolock and mmaplock held, the page cache of the out file will |
1447 | * be truncated, and any leases on the out file will have been broken. This | |
1448 | * function borrows heavily from xfs_file_aio_write_checks. | |
dceeb47b DC |
1449 | * |
1450 | * The VFS allows partial EOF blocks to "match" for dedupe even though it hasn't | |
1451 | * checked that the bytes beyond EOF physically match. Hence we cannot use the | |
1452 | * EOF block in the source dedupe range because it's not a complete block match, | |
b3998900 | 1453 | * hence can introduce a corruption into the file that has it's block replaced. |
dceeb47b | 1454 | * |
b3998900 DC |
1455 | * In similar fashion, the VFS file cloning also allows partial EOF blocks to be |
1456 | * "block aligned" for the purposes of cloning entire files. However, if the | |
1457 | * source file range includes the EOF block and it lands within the existing EOF | |
1458 | * of the destination file, then we can expose stale data from beyond the source | |
1459 | * file EOF in the destination file. | |
1460 | * | |
1461 | * XFS doesn't support partial block sharing, so in both cases we have check | |
1462 | * these cases ourselves. For dedupe, we can simply round the length to dedupe | |
1463 | * down to the previous whole block and ignore the partial EOF block. While this | |
1464 | * means we can't dedupe the last block of a file, this is an acceptible | |
1465 | * tradeoff for simplicity on implementation. | |
1466 | * | |
1467 | * For cloning, we want to share the partial EOF block if it is also the new EOF | |
1468 | * block of the destination file. If the partial EOF block lies inside the | |
1469 | * existing destination EOF, then we have to abort the clone to avoid exposing | |
1470 | * stale data in the destination file. Hence we reject these clone attempts with | |
1471 | * -EINVAL in this case. | |
862bb360 | 1472 | */ |
3fc9f5e4 | 1473 | int |
0d41e1d2 | 1474 | xfs_reflink_remap_prep( |
5faaf4fa CH |
1475 | struct file *file_in, |
1476 | loff_t pos_in, | |
1477 | struct file *file_out, | |
1478 | loff_t pos_out, | |
42ec3d4c | 1479 | loff_t *len, |
a91ae49b | 1480 | unsigned int remap_flags) |
862bb360 | 1481 | { |
5faaf4fa CH |
1482 | struct inode *inode_in = file_inode(file_in); |
1483 | struct xfs_inode *src = XFS_I(inode_in); | |
1484 | struct inode *inode_out = file_inode(file_out); | |
1485 | struct xfs_inode *dest = XFS_I(inode_out); | |
451d34ee | 1486 | int ret; |
862bb360 | 1487 | |
5faaf4fa | 1488 | /* Lock both files against IO */ |
e2aaee9c | 1489 | ret = xfs_ilock2_io_mmap(src, dest); |
1364b1d4 DW |
1490 | if (ret) |
1491 | return ret; | |
5faaf4fa | 1492 | |
876bec6f | 1493 | /* Check file eligibility and prepare for block sharing. */ |
5faaf4fa | 1494 | ret = -EINVAL; |
862bb360 DW |
1495 | /* Don't reflink realtime inodes */ |
1496 | if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest)) | |
5faaf4fa CH |
1497 | goto out_unlock; |
1498 | ||
13f9e267 SR |
1499 | /* Don't share DAX file data with non-DAX file. */ |
1500 | if (IS_DAX(inode_in) != IS_DAX(inode_out)) | |
5faaf4fa CH |
1501 | goto out_unlock; |
1502 | ||
6f7db389 SR |
1503 | if (!IS_DAX(inode_in)) |
1504 | ret = generic_remap_file_range_prep(file_in, pos_in, file_out, | |
1505 | pos_out, len, remap_flags); | |
1506 | else | |
1507 | ret = dax_remap_file_range_prep(file_in, pos_in, file_out, | |
1508 | pos_out, len, remap_flags, &xfs_read_iomap_ops); | |
451d34ee | 1509 | if (ret || *len == 0) |
5faaf4fa CH |
1510 | goto out_unlock; |
1511 | ||
09ac8623 | 1512 | /* Attach dquots to dest inode before changing block map */ |
c14cfcca | 1513 | ret = xfs_qm_dqattach(dest); |
09ac8623 DW |
1514 | if (ret) |
1515 | goto out_unlock; | |
1516 | ||
5c989a0e | 1517 | /* |
410fdc72 DW |
1518 | * Zero existing post-eof speculative preallocations in the destination |
1519 | * file. | |
5c989a0e | 1520 | */ |
410fdc72 DW |
1521 | ret = xfs_reflink_zero_posteof(dest, pos_out); |
1522 | if (ret) | |
1523 | goto out_unlock; | |
5c989a0e | 1524 | |
876bec6f | 1525 | /* Set flags and remap blocks. */ |
5faaf4fa CH |
1526 | ret = xfs_reflink_set_inode_flag(src, dest); |
1527 | if (ret) | |
1528 | goto out_unlock; | |
862bb360 | 1529 | |
2c307174 DC |
1530 | /* |
1531 | * If pos_out > EOF, we may have dirtied blocks between EOF and | |
1532 | * pos_out. In that case, we need to extend the flush and unmap to cover | |
1533 | * from EOF to the end of the copy length. | |
1534 | */ | |
1535 | if (pos_out > XFS_ISIZE(dest)) { | |
1536 | loff_t flen = *len + (pos_out - XFS_ISIZE(dest)); | |
1537 | ret = xfs_flush_unmap_range(dest, XFS_ISIZE(dest), flen); | |
1538 | } else { | |
1539 | ret = xfs_flush_unmap_range(dest, pos_out, *len); | |
1540 | } | |
1541 | if (ret) | |
1542 | goto out_unlock; | |
7debbf01 | 1543 | |
14a53798 CH |
1544 | xfs_iflags_set(src, XFS_IREMAPPING); |
1545 | if (inode_in != inode_out) | |
1546 | xfs_ilock_demote(src, XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL); | |
1547 | ||
451d34ee | 1548 | return 0; |
0d41e1d2 | 1549 | out_unlock: |
e2aaee9c | 1550 | xfs_iunlock2_io_mmap(src, dest); |
0d41e1d2 DW |
1551 | return ret; |
1552 | } | |
1553 | ||
ea7cdd7b | 1554 | /* Does this inode need the reflink flag? */ |
98cc2db5 | 1555 | int |
ea7cdd7b DW |
1556 | xfs_reflink_inode_has_shared_extents( |
1557 | struct xfs_trans *tp, | |
1558 | struct xfs_inode *ip, | |
1559 | bool *has_shared) | |
98cc2db5 | 1560 | { |
ea7cdd7b DW |
1561 | struct xfs_bmbt_irec got; |
1562 | struct xfs_mount *mp = ip->i_mount; | |
1563 | struct xfs_ifork *ifp; | |
b2b1712a | 1564 | struct xfs_iext_cursor icur; |
ea7cdd7b DW |
1565 | bool found; |
1566 | int error; | |
98cc2db5 | 1567 | |
732436ef | 1568 | ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK); |
862a804a CH |
1569 | error = xfs_iread_extents(tp, ip, XFS_DATA_FORK); |
1570 | if (error) | |
1571 | return error; | |
98cc2db5 | 1572 | |
ea7cdd7b | 1573 | *has_shared = false; |
b2b1712a | 1574 | found = xfs_iext_lookup_extent(ip, ifp, 0, &icur, &got); |
ea7cdd7b | 1575 | while (found) { |
08d3e84f DC |
1576 | struct xfs_perag *pag; |
1577 | xfs_agblock_t agbno; | |
1578 | xfs_extlen_t aglen; | |
1579 | xfs_agblock_t rbno; | |
1580 | xfs_extlen_t rlen; | |
1581 | ||
ea7cdd7b DW |
1582 | if (isnullstartblock(got.br_startblock) || |
1583 | got.br_state != XFS_EXT_NORM) | |
1584 | goto next; | |
08d3e84f DC |
1585 | |
1586 | pag = xfs_perag_get(mp, XFS_FSB_TO_AGNO(mp, got.br_startblock)); | |
ea7cdd7b DW |
1587 | agbno = XFS_FSB_TO_AGBNO(mp, got.br_startblock); |
1588 | aglen = got.br_blockcount; | |
08d3e84f | 1589 | error = xfs_reflink_find_shared(pag, tp, agbno, aglen, |
024adf48 | 1590 | &rbno, &rlen, false); |
08d3e84f | 1591 | xfs_perag_put(pag); |
024adf48 DW |
1592 | if (error) |
1593 | return error; | |
08d3e84f | 1594 | |
024adf48 | 1595 | /* Is there still a shared block here? */ |
ea7cdd7b DW |
1596 | if (rbno != NULLAGBLOCK) { |
1597 | *has_shared = true; | |
024adf48 | 1598 | return 0; |
ea7cdd7b | 1599 | } |
98cc2db5 | 1600 | next: |
b2b1712a | 1601 | found = xfs_iext_next_extent(ifp, &icur, &got); |
98cc2db5 DW |
1602 | } |
1603 | ||
ea7cdd7b DW |
1604 | return 0; |
1605 | } | |
1606 | ||
844e5e74 DC |
1607 | /* |
1608 | * Clear the inode reflink flag if there are no shared extents. | |
1609 | * | |
1610 | * The caller is responsible for joining the inode to the transaction passed in. | |
1611 | * The inode will be joined to the transaction that is returned to the caller. | |
1612 | */ | |
ea7cdd7b DW |
1613 | int |
1614 | xfs_reflink_clear_inode_flag( | |
1615 | struct xfs_inode *ip, | |
1616 | struct xfs_trans **tpp) | |
1617 | { | |
1618 | bool needs_flag; | |
1619 | int error = 0; | |
1620 | ||
1621 | ASSERT(xfs_is_reflink_inode(ip)); | |
1622 | ||
1623 | error = xfs_reflink_inode_has_shared_extents(*tpp, ip, &needs_flag); | |
1624 | if (error || needs_flag) | |
1625 | return error; | |
1626 | ||
98cc2db5 DW |
1627 | /* |
1628 | * We didn't find any shared blocks so turn off the reflink flag. | |
1629 | * First, get rid of any leftover CoW mappings. | |
1630 | */ | |
a5084865 DW |
1631 | error = xfs_reflink_cancel_cow_blocks(ip, tpp, 0, XFS_MAX_FILEOFF, |
1632 | true); | |
98cc2db5 DW |
1633 | if (error) |
1634 | return error; | |
1635 | ||
1636 | /* Clear the inode flag. */ | |
1637 | trace_xfs_reflink_unset_inode_flag(ip); | |
3e09ab8f | 1638 | ip->i_diflags2 &= ~XFS_DIFLAG2_REFLINK; |
83104d44 | 1639 | xfs_inode_clear_cowblocks_tag(ip); |
98cc2db5 DW |
1640 | xfs_trans_log_inode(*tpp, ip, XFS_ILOG_CORE); |
1641 | ||
1642 | return error; | |
1643 | } | |
1644 | ||
1645 | /* | |
1646 | * Clear the inode reflink flag if there are no shared extents and the size | |
1647 | * hasn't changed. | |
1648 | */ | |
1649 | STATIC int | |
1650 | xfs_reflink_try_clear_inode_flag( | |
97a1b87e | 1651 | struct xfs_inode *ip) |
98cc2db5 DW |
1652 | { |
1653 | struct xfs_mount *mp = ip->i_mount; | |
1654 | struct xfs_trans *tp; | |
1655 | int error = 0; | |
1656 | ||
1657 | /* Start a rolling transaction to remove the mappings */ | |
1658 | error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp); | |
1659 | if (error) | |
1660 | return error; | |
1661 | ||
1662 | xfs_ilock(ip, XFS_ILOCK_EXCL); | |
1663 | xfs_trans_ijoin(tp, ip, 0); | |
1664 | ||
98cc2db5 DW |
1665 | error = xfs_reflink_clear_inode_flag(ip, &tp); |
1666 | if (error) | |
1667 | goto cancel; | |
1668 | ||
1669 | error = xfs_trans_commit(tp); | |
1670 | if (error) | |
1671 | goto out; | |
1672 | ||
1673 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1674 | return 0; | |
1675 | cancel: | |
1676 | xfs_trans_cancel(tp); | |
1677 | out: | |
1678 | xfs_iunlock(ip, XFS_ILOCK_EXCL); | |
1679 | return error; | |
1680 | } | |
1681 | ||
1682 | /* | |
1683 | * Pre-COW all shared blocks within a given byte range of a file and turn off | |
1684 | * the reflink flag if we unshare all of the file's blocks. | |
1685 | */ | |
1686 | int | |
1687 | xfs_reflink_unshare( | |
1688 | struct xfs_inode *ip, | |
1689 | xfs_off_t offset, | |
1690 | xfs_off_t len) | |
1691 | { | |
dd26b846 | 1692 | struct inode *inode = VFS_I(ip); |
98cc2db5 DW |
1693 | int error; |
1694 | ||
1695 | if (!xfs_is_reflink_inode(ip)) | |
1696 | return 0; | |
1697 | ||
1698 | trace_xfs_reflink_unshare(ip, offset, len); | |
1699 | ||
dd26b846 | 1700 | inode_dio_wait(inode); |
98cc2db5 | 1701 | |
d984648e SR |
1702 | if (IS_DAX(inode)) |
1703 | error = dax_file_unshare(inode, offset, len, | |
1704 | &xfs_dax_write_iomap_ops); | |
1705 | else | |
1706 | error = iomap_file_unshare(inode, offset, len, | |
1707 | &xfs_buffered_write_iomap_ops); | |
98cc2db5 | 1708 | if (error) |
dd26b846 | 1709 | goto out; |
46afb062 | 1710 | |
d4f74e16 DW |
1711 | error = filemap_write_and_wait_range(inode->i_mapping, offset, |
1712 | offset + len - 1); | |
98cc2db5 DW |
1713 | if (error) |
1714 | goto out; | |
1715 | ||
97a1b87e DW |
1716 | /* Turn off the reflink flag if possible. */ |
1717 | error = xfs_reflink_try_clear_inode_flag(ip); | |
1718 | if (error) | |
1719 | goto out; | |
98cc2db5 DW |
1720 | return 0; |
1721 | ||
98cc2db5 DW |
1722 | out: |
1723 | trace_xfs_reflink_unshare_error(ip, error, _RET_IP_); | |
1724 | return error; | |
1725 | } |