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37b3b4d6 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
a18e1f79 DW |
2 | /* |
3 | * Copyright (C) 2016 Oracle. All Rights Reserved. | |
a18e1f79 | 4 | * Author: Darrick J. Wong <darrick.wong@oracle.com> |
a18e1f79 DW |
5 | */ |
6 | #include "libxfs_priv.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_bit.h" | |
13 | #include "xfs_sb.h" | |
14 | #include "xfs_mount.h" | |
15 | #include "xfs_defer.h" | |
16 | #include "xfs_trans.h" | |
c0860494 | 17 | #include "xfs_inode.h" |
a18e1f79 DW |
18 | #include "xfs_trace.h" |
19 | ||
20 | /* | |
21 | * Deferred Operations in XFS | |
22 | * | |
23 | * Due to the way locking rules work in XFS, certain transactions (block | |
24 | * mapping and unmapping, typically) have permanent reservations so that | |
25 | * we can roll the transaction to adhere to AG locking order rules and | |
26 | * to unlock buffers between metadata updates. Prior to rmap/reflink, | |
27 | * the mapping code had a mechanism to perform these deferrals for | |
28 | * extents that were going to be freed; this code makes that facility | |
29 | * more generic. | |
30 | * | |
31 | * When adding the reverse mapping and reflink features, it became | |
32 | * necessary to perform complex remapping multi-transactions to comply | |
33 | * with AG locking order rules, and to be able to spread a single | |
34 | * refcount update operation (an operation on an n-block extent can | |
35 | * update as many as n records!) among multiple transactions. XFS can | |
36 | * roll a transaction to facilitate this, but using this facility | |
37 | * requires us to log "intent" items in case log recovery needs to | |
38 | * redo the operation, and to log "done" items to indicate that redo | |
39 | * is not necessary. | |
40 | * | |
41 | * Deferred work is tracked in xfs_defer_pending items. Each pending | |
42 | * item tracks one type of deferred work. Incoming work items (which | |
43 | * have not yet had an intent logged) are attached to a pending item | |
44 | * on the dop_intake list, where they wait for the caller to finish | |
45 | * the deferred operations. | |
46 | * | |
47 | * Finishing a set of deferred operations is an involved process. To | |
48 | * start, we define "rolling a deferred-op transaction" as follows: | |
49 | * | |
50 | * > For each xfs_defer_pending item on the dop_intake list, | |
51 | * - Sort the work items in AG order. XFS locking | |
52 | * order rules require us to lock buffers in AG order. | |
53 | * - Create a log intent item for that type. | |
54 | * - Attach it to the pending item. | |
55 | * - Move the pending item from the dop_intake list to the | |
56 | * dop_pending list. | |
57 | * > Roll the transaction. | |
58 | * | |
59 | * NOTE: To avoid exceeding the transaction reservation, we limit the | |
60 | * number of items that we attach to a given xfs_defer_pending. | |
61 | * | |
62 | * The actual finishing process looks like this: | |
63 | * | |
64 | * > For each xfs_defer_pending in the dop_pending list, | |
65 | * - Roll the deferred-op transaction as above. | |
66 | * - Create a log done item for that type, and attach it to the | |
67 | * log intent item. | |
68 | * - For each work item attached to the log intent item, | |
69 | * * Perform the described action. | |
70 | * * Attach the work item to the log done item. | |
0590692e DW |
71 | * * If the result of doing the work was -EAGAIN, ->finish work |
72 | * wants a new transaction. See the "Requesting a Fresh | |
73 | * Transaction while Finishing Deferred Work" section below for | |
74 | * details. | |
a18e1f79 DW |
75 | * |
76 | * The key here is that we must log an intent item for all pending | |
77 | * work items every time we roll the transaction, and that we must log | |
78 | * a done item as soon as the work is completed. With this mechanism | |
79 | * we can perform complex remapping operations, chaining intent items | |
80 | * as needed. | |
81 | * | |
0590692e DW |
82 | * Requesting a Fresh Transaction while Finishing Deferred Work |
83 | * | |
84 | * If ->finish_item decides that it needs a fresh transaction to | |
85 | * finish the work, it must ask its caller (xfs_defer_finish) for a | |
86 | * continuation. The most likely cause of this circumstance are the | |
87 | * refcount adjust functions deciding that they've logged enough items | |
88 | * to be at risk of exceeding the transaction reservation. | |
89 | * | |
90 | * To get a fresh transaction, we want to log the existing log done | |
91 | * item to prevent the log intent item from replaying, immediately log | |
92 | * a new log intent item with the unfinished work items, roll the | |
93 | * transaction, and re-call ->finish_item wherever it left off. The | |
94 | * log done item and the new log intent item must be in the same | |
95 | * transaction or atomicity cannot be guaranteed; defer_finish ensures | |
96 | * that this happens. | |
97 | * | |
98 | * This requires some coordination between ->finish_item and | |
99 | * defer_finish. Upon deciding to request a new transaction, | |
100 | * ->finish_item should update the current work item to reflect the | |
101 | * unfinished work. Next, it should reset the log done item's list | |
102 | * count to the number of items finished, and return -EAGAIN. | |
103 | * defer_finish sees the -EAGAIN, logs the new log intent item | |
104 | * with the remaining work items, and leaves the xfs_defer_pending | |
105 | * item at the head of the dop_work queue. Then it rolls the | |
106 | * transaction and picks up processing where it left off. It is | |
107 | * required that ->finish_item must be careful to leave enough | |
108 | * transaction reservation to fit the new log intent item. | |
109 | * | |
a18e1f79 DW |
110 | * This is an example of remapping the extent (E, E+B) into file X at |
111 | * offset A and dealing with the extent (C, C+B) already being mapped | |
112 | * there: | |
113 | * +-------------------------------------------------+ | |
114 | * | Unmap file X startblock C offset A length B | t0 | |
115 | * | Intent to reduce refcount for extent (C, B) | | |
116 | * | Intent to remove rmap (X, C, A, B) | | |
117 | * | Intent to free extent (D, 1) (bmbt block) | | |
118 | * | Intent to map (X, A, B) at startblock E | | |
119 | * +-------------------------------------------------+ | |
120 | * | Map file X startblock E offset A length B | t1 | |
121 | * | Done mapping (X, E, A, B) | | |
122 | * | Intent to increase refcount for extent (E, B) | | |
123 | * | Intent to add rmap (X, E, A, B) | | |
124 | * +-------------------------------------------------+ | |
125 | * | Reduce refcount for extent (C, B) | t2 | |
0590692e DW |
126 | * | Done reducing refcount for extent (C, 9) | |
127 | * | Intent to reduce refcount for extent (C+9, B-9) | | |
128 | * | (ran out of space after 9 refcount updates) | | |
129 | * +-------------------------------------------------+ | |
130 | * | Reduce refcount for extent (C+9, B+9) | t3 | |
131 | * | Done reducing refcount for extent (C+9, B-9) | | |
a18e1f79 DW |
132 | * | Increase refcount for extent (E, B) | |
133 | * | Done increasing refcount for extent (E, B) | | |
134 | * | Intent to free extent (C, B) | | |
135 | * | Intent to free extent (F, 1) (refcountbt block) | | |
136 | * | Intent to remove rmap (F, 1, REFC) | | |
137 | * +-------------------------------------------------+ | |
0590692e | 138 | * | Remove rmap (X, C, A, B) | t4 |
a18e1f79 DW |
139 | * | Done removing rmap (X, C, A, B) | |
140 | * | Add rmap (X, E, A, B) | | |
141 | * | Done adding rmap (X, E, A, B) | | |
142 | * | Remove rmap (F, 1, REFC) | | |
143 | * | Done removing rmap (F, 1, REFC) | | |
144 | * +-------------------------------------------------+ | |
0590692e | 145 | * | Free extent (C, B) | t5 |
a18e1f79 DW |
146 | * | Done freeing extent (C, B) | |
147 | * | Free extent (D, 1) | | |
148 | * | Done freeing extent (D, 1) | | |
149 | * | Free extent (F, 1) | | |
150 | * | Done freeing extent (F, 1) | | |
151 | * +-------------------------------------------------+ | |
152 | * | |
153 | * If we should crash before t2 commits, log recovery replays | |
154 | * the following intent items: | |
155 | * | |
156 | * - Intent to reduce refcount for extent (C, B) | |
157 | * - Intent to remove rmap (X, C, A, B) | |
158 | * - Intent to free extent (D, 1) (bmbt block) | |
159 | * - Intent to increase refcount for extent (E, B) | |
160 | * - Intent to add rmap (X, E, A, B) | |
161 | * | |
162 | * In the process of recovering, it should also generate and take care | |
163 | * of these intent items: | |
164 | * | |
165 | * - Intent to free extent (C, B) | |
166 | * - Intent to free extent (F, 1) (refcountbt block) | |
167 | * - Intent to remove rmap (F, 1, REFC) | |
0590692e DW |
168 | * |
169 | * Note that the continuation requested between t2 and t3 is likely to | |
170 | * reoccur. | |
a18e1f79 DW |
171 | */ |
172 | ||
173 | static const struct xfs_defer_op_type *defer_op_types[XFS_DEFER_OPS_TYPE_MAX]; | |
174 | ||
175 | /* | |
176 | * For each pending item in the intake list, log its intent item and the | |
177 | * associated extents, then add the entire intake list to the end of | |
178 | * the pending list. | |
179 | */ | |
180 | STATIC void | |
3e1da129 | 181 | xfs_defer_create_intents( |
1e6b0a71 | 182 | struct xfs_trans *tp) |
a18e1f79 DW |
183 | { |
184 | struct list_head *li; | |
185 | struct xfs_defer_pending *dfp; | |
186 | ||
92a8736e | 187 | list_for_each_entry(dfp, &tp->t_dfops, dfp_list) { |
a18e1f79 DW |
188 | dfp->dfp_intent = dfp->dfp_type->create_intent(tp, |
189 | dfp->dfp_count); | |
3e1da129 | 190 | trace_xfs_defer_create_intent(tp->t_mountp, dfp); |
a18e1f79 DW |
191 | list_sort(tp->t_mountp, &dfp->dfp_work, |
192 | dfp->dfp_type->diff_items); | |
193 | list_for_each(li, &dfp->dfp_work) | |
194 | dfp->dfp_type->log_item(tp, dfp->dfp_intent, li); | |
195 | } | |
a18e1f79 DW |
196 | } |
197 | ||
198 | /* Abort all the intents that were committed. */ | |
199 | STATIC void | |
200 | xfs_defer_trans_abort( | |
201 | struct xfs_trans *tp, | |
3e1da129 | 202 | struct list_head *dop_pending) |
a18e1f79 DW |
203 | { |
204 | struct xfs_defer_pending *dfp; | |
205 | ||
92a8736e | 206 | trace_xfs_defer_trans_abort(tp, _RET_IP_); |
a18e1f79 | 207 | |
077dd509 | 208 | /* Abort intent items that don't have a done item. */ |
3e1da129 | 209 | list_for_each_entry(dfp, dop_pending, dfp_list) { |
30ad7d6e | 210 | trace_xfs_defer_pending_abort(tp->t_mountp, dfp); |
077dd509 | 211 | if (dfp->dfp_intent && !dfp->dfp_done) { |
a18e1f79 | 212 | dfp->dfp_type->abort_intent(dfp->dfp_intent); |
077dd509 DW |
213 | dfp->dfp_intent = NULL; |
214 | } | |
a18e1f79 | 215 | } |
a18e1f79 DW |
216 | } |
217 | ||
218 | /* Roll a transaction so we can do some deferred op processing. */ | |
219 | STATIC int | |
220 | xfs_defer_trans_roll( | |
3e1da129 | 221 | struct xfs_trans **tpp) |
a18e1f79 | 222 | { |
3e1da129 | 223 | struct xfs_trans *tp = *tpp; |
f2ea6bf0 | 224 | struct xfs_buf_log_item *bli; |
c0860494 | 225 | struct xfs_inode_log_item *ili; |
f2ea6bf0 BF |
226 | struct xfs_log_item *lip; |
227 | struct xfs_buf *bplist[XFS_DEFER_OPS_NR_BUFS]; | |
c0860494 BF |
228 | struct xfs_inode *iplist[XFS_DEFER_OPS_NR_INODES]; |
229 | int bpcount = 0, ipcount = 0; | |
a18e1f79 DW |
230 | int i; |
231 | int error; | |
232 | ||
3e1da129 | 233 | list_for_each_entry(lip, &tp->t_items, li_trans) { |
f2ea6bf0 BF |
234 | switch (lip->li_type) { |
235 | case XFS_LI_BUF: | |
236 | bli = container_of(lip, struct xfs_buf_log_item, | |
237 | bli_item); | |
238 | if (bli->bli_flags & XFS_BLI_HOLD) { | |
239 | if (bpcount >= XFS_DEFER_OPS_NR_BUFS) { | |
240 | ASSERT(0); | |
241 | return -EFSCORRUPTED; | |
242 | } | |
3e1da129 | 243 | xfs_trans_dirty_buf(tp, bli->bli_buf); |
f2ea6bf0 BF |
244 | bplist[bpcount++] = bli->bli_buf; |
245 | } | |
246 | break; | |
c0860494 BF |
247 | case XFS_LI_INODE: |
248 | ili = container_of(lip, struct xfs_inode_log_item, | |
249 | ili_item); | |
250 | if (ili->ili_lock_flags == 0) { | |
251 | if (ipcount >= XFS_DEFER_OPS_NR_INODES) { | |
252 | ASSERT(0); | |
253 | return -EFSCORRUPTED; | |
254 | } | |
3e1da129 | 255 | xfs_trans_log_inode(tp, ili->ili_inode, |
c0860494 BF |
256 | XFS_ILOG_CORE); |
257 | iplist[ipcount++] = ili->ili_inode; | |
258 | } | |
259 | break; | |
f2ea6bf0 BF |
260 | default: |
261 | break; | |
262 | } | |
263 | } | |
6f67c32d | 264 | |
92a8736e | 265 | trace_xfs_defer_trans_roll(tp, _RET_IP_); |
30ad7d6e | 266 | |
a18e1f79 | 267 | /* Roll the transaction. */ |
3e1da129 BF |
268 | error = xfs_trans_roll(tpp); |
269 | tp = *tpp; | |
a18e1f79 | 270 | if (error) { |
92a8736e | 271 | trace_xfs_defer_trans_roll_error(tp, error); |
a18e1f79 DW |
272 | return error; |
273 | } | |
a18e1f79 | 274 | |
d67406c9 | 275 | /* Rejoin the joined inodes. */ |
c0860494 | 276 | for (i = 0; i < ipcount; i++) |
3e1da129 | 277 | xfs_trans_ijoin(tp, iplist[i], 0); |
a18e1f79 | 278 | |
6f67c32d | 279 | /* Rejoin the buffers and dirty them so the log moves forward. */ |
f2ea6bf0 | 280 | for (i = 0; i < bpcount; i++) { |
3e1da129 BF |
281 | xfs_trans_bjoin(tp, bplist[i]); |
282 | xfs_trans_bhold(tp, bplist[i]); | |
6f67c32d DW |
283 | } |
284 | ||
a18e1f79 DW |
285 | return error; |
286 | } | |
287 | ||
1a3fd2f9 BF |
288 | /* |
289 | * Reset an already used dfops after finish. | |
290 | */ | |
291 | static void | |
292 | xfs_defer_reset( | |
76a3c33d | 293 | struct xfs_trans *tp) |
1a3fd2f9 | 294 | { |
92a8736e | 295 | ASSERT(list_empty(&tp->t_dfops)); |
565e96c6 BF |
296 | |
297 | /* | |
298 | * Low mode state transfers across transaction rolls to mirror dfops | |
299 | * lifetime. Clear it now that dfops is reset. | |
300 | */ | |
301 | tp->t_flags &= ~XFS_TRANS_LOWMODE; | |
1a3fd2f9 BF |
302 | } |
303 | ||
3e1da129 BF |
304 | /* |
305 | * Free up any items left in the list. | |
306 | */ | |
307 | static void | |
308 | xfs_defer_cancel_list( | |
309 | struct xfs_mount *mp, | |
310 | struct list_head *dop_list) | |
311 | { | |
312 | struct xfs_defer_pending *dfp; | |
313 | struct xfs_defer_pending *pli; | |
314 | struct list_head *pwi; | |
315 | struct list_head *n; | |
316 | ||
317 | /* | |
318 | * Free the pending items. Caller should already have arranged | |
319 | * for the intent items to be released. | |
320 | */ | |
321 | list_for_each_entry_safe(dfp, pli, dop_list, dfp_list) { | |
322 | trace_xfs_defer_cancel_list(mp, dfp); | |
323 | list_del(&dfp->dfp_list); | |
324 | list_for_each_safe(pwi, n, &dfp->dfp_work) { | |
325 | list_del(pwi); | |
326 | dfp->dfp_count--; | |
327 | dfp->dfp_type->cancel_item(pwi); | |
328 | } | |
329 | ASSERT(dfp->dfp_count == 0); | |
330 | kmem_free(dfp); | |
331 | } | |
332 | } | |
333 | ||
a18e1f79 DW |
334 | /* |
335 | * Finish all the pending work. This involves logging intent items for | |
336 | * any work items that wandered in since the last transaction roll (if | |
337 | * one has even happened), rolling the transaction, and finishing the | |
338 | * work items in the first item on the logged-and-pending list. | |
339 | * | |
340 | * If an inode is provided, relog it to the new transaction. | |
341 | */ | |
342 | int | |
ca7e896f | 343 | xfs_defer_finish_noroll( |
ac0a2228 | 344 | struct xfs_trans **tp) |
a18e1f79 DW |
345 | { |
346 | struct xfs_defer_pending *dfp; | |
347 | struct list_head *li; | |
348 | struct list_head *n; | |
a18e1f79 DW |
349 | void *state; |
350 | int error = 0; | |
351 | void (*cleanup_fn)(struct xfs_trans *, void *, int); | |
3e1da129 | 352 | LIST_HEAD(dop_pending); |
a18e1f79 DW |
353 | |
354 | ASSERT((*tp)->t_flags & XFS_TRANS_PERM_LOG_RES); | |
355 | ||
92a8736e | 356 | trace_xfs_defer_finish(*tp, _RET_IP_); |
30ad7d6e | 357 | |
a18e1f79 | 358 | /* Until we run out of pending work to finish... */ |
92a8736e | 359 | while (!list_empty(&dop_pending) || !list_empty(&(*tp)->t_dfops)) { |
3e1da129 BF |
360 | /* log intents and pull in intake items */ |
361 | xfs_defer_create_intents(*tp); | |
92a8736e | 362 | list_splice_tail_init(&(*tp)->t_dfops, &dop_pending); |
a18e1f79 | 363 | |
ad84d074 | 364 | /* |
1e6b0a71 | 365 | * Roll the transaction. |
ad84d074 BF |
366 | */ |
367 | error = xfs_defer_trans_roll(tp); | |
a18e1f79 DW |
368 | if (error) |
369 | goto out; | |
370 | ||
a18e1f79 | 371 | /* Log an intent-done item for the first pending item. */ |
3e1da129 BF |
372 | dfp = list_first_entry(&dop_pending, struct xfs_defer_pending, |
373 | dfp_list); | |
30ad7d6e | 374 | trace_xfs_defer_pending_finish((*tp)->t_mountp, dfp); |
11d87237 | 375 | dfp->dfp_done = dfp->dfp_type->create_done(*tp, dfp->dfp_intent, |
a18e1f79 DW |
376 | dfp->dfp_count); |
377 | cleanup_fn = dfp->dfp_type->finish_cleanup; | |
378 | ||
379 | /* Finish the work items. */ | |
380 | state = NULL; | |
381 | list_for_each_safe(li, n, &dfp->dfp_work) { | |
382 | list_del(li); | |
383 | dfp->dfp_count--; | |
7b3ab230 | 384 | error = dfp->dfp_type->finish_item(*tp, li, |
11d87237 | 385 | dfp->dfp_done, &state); |
0590692e DW |
386 | if (error == -EAGAIN) { |
387 | /* | |
388 | * Caller wants a fresh transaction; | |
389 | * put the work item back on the list | |
390 | * and jump out. | |
391 | */ | |
392 | list_add(li, &dfp->dfp_work); | |
393 | dfp->dfp_count++; | |
394 | break; | |
395 | } else if (error) { | |
a18e1f79 DW |
396 | /* |
397 | * Clean up after ourselves and jump out. | |
398 | * xfs_defer_cancel will take care of freeing | |
399 | * all these lists and stuff. | |
400 | */ | |
401 | if (cleanup_fn) | |
402 | cleanup_fn(*tp, state, error); | |
a18e1f79 DW |
403 | goto out; |
404 | } | |
405 | } | |
0590692e DW |
406 | if (error == -EAGAIN) { |
407 | /* | |
408 | * Caller wants a fresh transaction, so log a | |
409 | * new log intent item to replace the old one | |
410 | * and roll the transaction. See "Requesting | |
411 | * a Fresh Transaction while Finishing | |
412 | * Deferred Work" above. | |
413 | */ | |
414 | dfp->dfp_intent = dfp->dfp_type->create_intent(*tp, | |
415 | dfp->dfp_count); | |
416 | dfp->dfp_done = NULL; | |
417 | list_for_each(li, &dfp->dfp_work) | |
418 | dfp->dfp_type->log_item(*tp, dfp->dfp_intent, | |
419 | li); | |
420 | } else { | |
421 | /* Done with the dfp, free it. */ | |
422 | list_del(&dfp->dfp_list); | |
423 | kmem_free(dfp); | |
424 | } | |
a18e1f79 DW |
425 | |
426 | if (cleanup_fn) | |
427 | cleanup_fn(*tp, state, error); | |
428 | } | |
429 | ||
430 | out: | |
9f5a828b | 431 | if (error) { |
3e1da129 BF |
432 | xfs_defer_trans_abort(*tp, &dop_pending); |
433 | xfs_force_shutdown((*tp)->t_mountp, SHUTDOWN_CORRUPT_INCORE); | |
92a8736e | 434 | trace_xfs_defer_finish_error(*tp, error); |
3e1da129 | 435 | xfs_defer_cancel_list((*tp)->t_mountp, &dop_pending); |
9f5a828b BF |
436 | xfs_defer_cancel(*tp); |
437 | return error; | |
438 | } | |
1a3fd2f9 | 439 | |
92a8736e | 440 | trace_xfs_defer_finish_done(*tp, _RET_IP_); |
9f5a828b | 441 | return 0; |
a18e1f79 DW |
442 | } |
443 | ||
ca7e896f BF |
444 | int |
445 | xfs_defer_finish( | |
446 | struct xfs_trans **tp) | |
447 | { | |
448 | int error; | |
449 | ||
450 | /* | |
451 | * Finish and roll the transaction once more to avoid returning to the | |
452 | * caller with a dirty transaction. | |
453 | */ | |
454 | error = xfs_defer_finish_noroll(tp); | |
455 | if (error) | |
456 | return error; | |
457 | if ((*tp)->t_flags & XFS_TRANS_DIRTY) { | |
458 | error = xfs_defer_trans_roll(tp); | |
3e1da129 BF |
459 | if (error) { |
460 | xfs_force_shutdown((*tp)->t_mountp, | |
461 | SHUTDOWN_CORRUPT_INCORE); | |
ca7e896f | 462 | return error; |
3e1da129 | 463 | } |
ca7e896f | 464 | } |
76a3c33d | 465 | xfs_defer_reset(*tp); |
ca7e896f BF |
466 | return 0; |
467 | } | |
468 | ||
a18e1f79 | 469 | void |
22913550 | 470 | xfs_defer_cancel( |
3e1da129 | 471 | struct xfs_trans *tp) |
a18e1f79 | 472 | { |
3e1da129 | 473 | struct xfs_mount *mp = tp->t_mountp; |
a18e1f79 | 474 | |
92a8736e BF |
475 | trace_xfs_defer_cancel(tp, _RET_IP_); |
476 | xfs_defer_cancel_list(mp, &tp->t_dfops); | |
a18e1f79 DW |
477 | } |
478 | ||
479 | /* Add an item for later deferred processing. */ | |
480 | void | |
481 | xfs_defer_add( | |
21375e5d | 482 | struct xfs_trans *tp, |
a18e1f79 DW |
483 | enum xfs_defer_ops_type type, |
484 | struct list_head *li) | |
485 | { | |
486 | struct xfs_defer_pending *dfp = NULL; | |
487 | ||
21375e5d BF |
488 | ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES); |
489 | ||
a18e1f79 DW |
490 | /* |
491 | * Add the item to a pending item at the end of the intake list. | |
492 | * If the last pending item has the same type, reuse it. Else, | |
493 | * create a new pending item at the end of the intake list. | |
494 | */ | |
92a8736e BF |
495 | if (!list_empty(&tp->t_dfops)) { |
496 | dfp = list_last_entry(&tp->t_dfops, | |
a18e1f79 DW |
497 | struct xfs_defer_pending, dfp_list); |
498 | if (dfp->dfp_type->type != type || | |
499 | (dfp->dfp_type->max_items && | |
500 | dfp->dfp_count >= dfp->dfp_type->max_items)) | |
501 | dfp = NULL; | |
502 | } | |
503 | if (!dfp) { | |
504 | dfp = kmem_alloc(sizeof(struct xfs_defer_pending), | |
505 | KM_SLEEP | KM_NOFS); | |
506 | dfp->dfp_type = defer_op_types[type]; | |
a18e1f79 | 507 | dfp->dfp_intent = NULL; |
11d87237 | 508 | dfp->dfp_done = NULL; |
a18e1f79 DW |
509 | dfp->dfp_count = 0; |
510 | INIT_LIST_HEAD(&dfp->dfp_work); | |
92a8736e | 511 | list_add_tail(&dfp->dfp_list, &tp->t_dfops); |
a18e1f79 DW |
512 | } |
513 | ||
514 | list_add_tail(li, &dfp->dfp_work); | |
515 | dfp->dfp_count++; | |
516 | } | |
517 | ||
518 | /* Initialize a deferred operation list. */ | |
519 | void | |
520 | xfs_defer_init_op_type( | |
521 | const struct xfs_defer_op_type *type) | |
522 | { | |
523 | defer_op_types[type->type] = type; | |
524 | } | |
525 | ||
f5f4497f | 526 | /* |
92a8736e BF |
527 | * Move deferred ops from one transaction to another and reset the source to |
528 | * initial state. This is primarily used to carry state forward across | |
529 | * transaction rolls with pending dfops. | |
f5f4497f BF |
530 | */ |
531 | void | |
532 | xfs_defer_move( | |
76a3c33d BF |
533 | struct xfs_trans *dtp, |
534 | struct xfs_trans *stp) | |
f5f4497f | 535 | { |
92a8736e | 536 | list_splice_init(&stp->t_dfops, &dtp->t_dfops); |
f5f4497f | 537 | |
565e96c6 BF |
538 | /* |
539 | * Low free space mode was historically controlled by a dfops field. | |
540 | * This meant that low mode state potentially carried across multiple | |
541 | * transaction rolls. Transfer low mode on a dfops move to preserve | |
542 | * that behavior. | |
543 | */ | |
544 | dtp->t_flags |= (stp->t_flags & XFS_TRANS_LOWMODE); | |
f5f4497f | 545 | |
76a3c33d | 546 | xfs_defer_reset(stp); |
f5f4497f | 547 | } |