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71e330b5 DC |
1 | /* |
2 | * Copyright (c) 2010 Red Hat, Inc. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it would be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program; if not, write the Free Software Foundation, | |
15 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
16 | */ | |
17 | ||
18 | #include "xfs.h" | |
19 | #include "xfs_fs.h" | |
4fb6e8ad | 20 | #include "xfs_format.h" |
239880ef | 21 | #include "xfs_log_format.h" |
70a9883c | 22 | #include "xfs_shared.h" |
239880ef | 23 | #include "xfs_trans_resv.h" |
71e330b5 DC |
24 | #include "xfs_mount.h" |
25 | #include "xfs_error.h" | |
26 | #include "xfs_alloc.h" | |
efc27b52 | 27 | #include "xfs_extent_busy.h" |
e84661aa | 28 | #include "xfs_discard.h" |
239880ef DC |
29 | #include "xfs_trans.h" |
30 | #include "xfs_trans_priv.h" | |
31 | #include "xfs_log.h" | |
32 | #include "xfs_log_priv.h" | |
71e330b5 | 33 | |
71e330b5 DC |
34 | /* |
35 | * Allocate a new ticket. Failing to get a new ticket makes it really hard to | |
36 | * recover, so we don't allow failure here. Also, we allocate in a context that | |
37 | * we don't want to be issuing transactions from, so we need to tell the | |
38 | * allocation code this as well. | |
39 | * | |
40 | * We don't reserve any space for the ticket - we are going to steal whatever | |
41 | * space we require from transactions as they commit. To ensure we reserve all | |
42 | * the space required, we need to set the current reservation of the ticket to | |
43 | * zero so that we know to steal the initial transaction overhead from the | |
44 | * first transaction commit. | |
45 | */ | |
46 | static struct xlog_ticket * | |
47 | xlog_cil_ticket_alloc( | |
f7bdf03a | 48 | struct xlog *log) |
71e330b5 DC |
49 | { |
50 | struct xlog_ticket *tic; | |
51 | ||
52 | tic = xlog_ticket_alloc(log, 0, 1, XFS_TRANSACTION, 0, | |
53 | KM_SLEEP|KM_NOFS); | |
71e330b5 DC |
54 | |
55 | /* | |
56 | * set the current reservation to zero so we know to steal the basic | |
57 | * transaction overhead reservation from the first transaction commit. | |
58 | */ | |
59 | tic->t_curr_res = 0; | |
60 | return tic; | |
61 | } | |
62 | ||
63 | /* | |
64 | * After the first stage of log recovery is done, we know where the head and | |
65 | * tail of the log are. We need this log initialisation done before we can | |
66 | * initialise the first CIL checkpoint context. | |
67 | * | |
68 | * Here we allocate a log ticket to track space usage during a CIL push. This | |
69 | * ticket is passed to xlog_write() directly so that we don't slowly leak log | |
70 | * space by failing to account for space used by log headers and additional | |
71 | * region headers for split regions. | |
72 | */ | |
73 | void | |
74 | xlog_cil_init_post_recovery( | |
f7bdf03a | 75 | struct xlog *log) |
71e330b5 | 76 | { |
71e330b5 DC |
77 | log->l_cilp->xc_ctx->ticket = xlog_cil_ticket_alloc(log); |
78 | log->l_cilp->xc_ctx->sequence = 1; | |
71e330b5 DC |
79 | } |
80 | ||
b1c5ebb2 DC |
81 | static inline int |
82 | xlog_cil_iovec_space( | |
83 | uint niovecs) | |
84 | { | |
85 | return round_up((sizeof(struct xfs_log_vec) + | |
86 | niovecs * sizeof(struct xfs_log_iovec)), | |
87 | sizeof(uint64_t)); | |
88 | } | |
89 | ||
90 | /* | |
91 | * Allocate or pin log vector buffers for CIL insertion. | |
92 | * | |
93 | * The CIL currently uses disposable buffers for copying a snapshot of the | |
94 | * modified items into the log during a push. The biggest problem with this is | |
95 | * the requirement to allocate the disposable buffer during the commit if: | |
96 | * a) does not exist; or | |
97 | * b) it is too small | |
98 | * | |
99 | * If we do this allocation within xlog_cil_insert_format_items(), it is done | |
100 | * under the xc_ctx_lock, which means that a CIL push cannot occur during | |
101 | * the memory allocation. This means that we have a potential deadlock situation | |
102 | * under low memory conditions when we have lots of dirty metadata pinned in | |
103 | * the CIL and we need a CIL commit to occur to free memory. | |
104 | * | |
105 | * To avoid this, we need to move the memory allocation outside the | |
106 | * xc_ctx_lock, but because the log vector buffers are disposable, that opens | |
107 | * up a TOCTOU race condition w.r.t. the CIL committing and removing the log | |
108 | * vector buffers between the check and the formatting of the item into the | |
109 | * log vector buffer within the xc_ctx_lock. | |
110 | * | |
111 | * Because the log vector buffer needs to be unchanged during the CIL push | |
112 | * process, we cannot share the buffer between the transaction commit (which | |
113 | * modifies the buffer) and the CIL push context that is writing the changes | |
114 | * into the log. This means skipping preallocation of buffer space is | |
115 | * unreliable, but we most definitely do not want to be allocating and freeing | |
116 | * buffers unnecessarily during commits when overwrites can be done safely. | |
117 | * | |
118 | * The simplest solution to this problem is to allocate a shadow buffer when a | |
119 | * log item is committed for the second time, and then to only use this buffer | |
120 | * if necessary. The buffer can remain attached to the log item until such time | |
121 | * it is needed, and this is the buffer that is reallocated to match the size of | |
122 | * the incoming modification. Then during the formatting of the item we can swap | |
123 | * the active buffer with the new one if we can't reuse the existing buffer. We | |
124 | * don't free the old buffer as it may be reused on the next modification if | |
125 | * it's size is right, otherwise we'll free and reallocate it at that point. | |
126 | * | |
127 | * This function builds a vector for the changes in each log item in the | |
128 | * transaction. It then works out the length of the buffer needed for each log | |
129 | * item, allocates them and attaches the vector to the log item in preparation | |
130 | * for the formatting step which occurs under the xc_ctx_lock. | |
131 | * | |
132 | * While this means the memory footprint goes up, it avoids the repeated | |
133 | * alloc/free pattern that repeated modifications of an item would otherwise | |
134 | * cause, and hence minimises the CPU overhead of such behaviour. | |
135 | */ | |
136 | static void | |
137 | xlog_cil_alloc_shadow_bufs( | |
138 | struct xlog *log, | |
139 | struct xfs_trans *tp) | |
140 | { | |
141 | struct xfs_log_item_desc *lidp; | |
142 | ||
143 | list_for_each_entry(lidp, &tp->t_items, lid_trans) { | |
144 | struct xfs_log_item *lip = lidp->lid_item; | |
145 | struct xfs_log_vec *lv; | |
146 | int niovecs = 0; | |
147 | int nbytes = 0; | |
148 | int buf_size; | |
149 | bool ordered = false; | |
150 | ||
151 | /* Skip items which aren't dirty in this transaction. */ | |
152 | if (!(lidp->lid_flags & XFS_LID_DIRTY)) | |
153 | continue; | |
154 | ||
155 | /* get number of vecs and size of data to be stored */ | |
156 | lip->li_ops->iop_size(lip, &niovecs, &nbytes); | |
157 | ||
158 | /* | |
159 | * Ordered items need to be tracked but we do not wish to write | |
160 | * them. We need a logvec to track the object, but we do not | |
161 | * need an iovec or buffer to be allocated for copying data. | |
162 | */ | |
163 | if (niovecs == XFS_LOG_VEC_ORDERED) { | |
164 | ordered = true; | |
165 | niovecs = 0; | |
166 | nbytes = 0; | |
167 | } | |
168 | ||
169 | /* | |
170 | * We 64-bit align the length of each iovec so that the start | |
171 | * of the next one is naturally aligned. We'll need to | |
172 | * account for that slack space here. Then round nbytes up | |
173 | * to 64-bit alignment so that the initial buffer alignment is | |
174 | * easy to calculate and verify. | |
175 | */ | |
176 | nbytes += niovecs * sizeof(uint64_t); | |
177 | nbytes = round_up(nbytes, sizeof(uint64_t)); | |
178 | ||
179 | /* | |
180 | * The data buffer needs to start 64-bit aligned, so round up | |
181 | * that space to ensure we can align it appropriately and not | |
182 | * overrun the buffer. | |
183 | */ | |
184 | buf_size = nbytes + xlog_cil_iovec_space(niovecs); | |
185 | ||
186 | /* | |
187 | * if we have no shadow buffer, or it is too small, we need to | |
188 | * reallocate it. | |
189 | */ | |
190 | if (!lip->li_lv_shadow || | |
191 | buf_size > lip->li_lv_shadow->lv_size) { | |
192 | ||
193 | /* | |
194 | * We free and allocate here as a realloc would copy | |
195 | * unecessary data. We don't use kmem_zalloc() for the | |
196 | * same reason - we don't need to zero the data area in | |
197 | * the buffer, only the log vector header and the iovec | |
198 | * storage. | |
199 | */ | |
200 | kmem_free(lip->li_lv_shadow); | |
201 | ||
202 | lv = kmem_alloc(buf_size, KM_SLEEP|KM_NOFS); | |
203 | memset(lv, 0, xlog_cil_iovec_space(niovecs)); | |
204 | ||
205 | lv->lv_item = lip; | |
206 | lv->lv_size = buf_size; | |
207 | if (ordered) | |
208 | lv->lv_buf_len = XFS_LOG_VEC_ORDERED; | |
209 | else | |
210 | lv->lv_iovecp = (struct xfs_log_iovec *)&lv[1]; | |
211 | lip->li_lv_shadow = lv; | |
212 | } else { | |
213 | /* same or smaller, optimise common overwrite case */ | |
214 | lv = lip->li_lv_shadow; | |
215 | if (ordered) | |
216 | lv->lv_buf_len = XFS_LOG_VEC_ORDERED; | |
217 | else | |
218 | lv->lv_buf_len = 0; | |
219 | lv->lv_bytes = 0; | |
220 | lv->lv_next = NULL; | |
221 | } | |
222 | ||
223 | /* Ensure the lv is set up according to ->iop_size */ | |
224 | lv->lv_niovecs = niovecs; | |
225 | ||
226 | /* The allocated data region lies beyond the iovec region */ | |
227 | lv->lv_buf = (char *)lv + xlog_cil_iovec_space(niovecs); | |
228 | } | |
229 | ||
230 | } | |
231 | ||
991aaf65 DC |
232 | /* |
233 | * Prepare the log item for insertion into the CIL. Calculate the difference in | |
234 | * log space and vectors it will consume, and if it is a new item pin it as | |
235 | * well. | |
236 | */ | |
237 | STATIC void | |
238 | xfs_cil_prepare_item( | |
239 | struct xlog *log, | |
240 | struct xfs_log_vec *lv, | |
241 | struct xfs_log_vec *old_lv, | |
242 | int *diff_len, | |
243 | int *diff_iovecs) | |
244 | { | |
245 | /* Account for the new LV being passed in */ | |
246 | if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED) { | |
110dc24a | 247 | *diff_len += lv->lv_bytes; |
991aaf65 DC |
248 | *diff_iovecs += lv->lv_niovecs; |
249 | } | |
250 | ||
251 | /* | |
252 | * If there is no old LV, this is the first time we've seen the item in | |
253 | * this CIL context and so we need to pin it. If we are replacing the | |
b1c5ebb2 DC |
254 | * old_lv, then remove the space it accounts for and make it the shadow |
255 | * buffer for later freeing. In both cases we are now switching to the | |
256 | * shadow buffer, so update the the pointer to it appropriately. | |
991aaf65 | 257 | */ |
b1c5ebb2 | 258 | if (!old_lv) { |
991aaf65 | 259 | lv->lv_item->li_ops->iop_pin(lv->lv_item); |
b1c5ebb2 DC |
260 | lv->lv_item->li_lv_shadow = NULL; |
261 | } else if (old_lv != lv) { | |
991aaf65 DC |
262 | ASSERT(lv->lv_buf_len != XFS_LOG_VEC_ORDERED); |
263 | ||
110dc24a | 264 | *diff_len -= old_lv->lv_bytes; |
991aaf65 | 265 | *diff_iovecs -= old_lv->lv_niovecs; |
b1c5ebb2 | 266 | lv->lv_item->li_lv_shadow = old_lv; |
991aaf65 DC |
267 | } |
268 | ||
269 | /* attach new log vector to log item */ | |
270 | lv->lv_item->li_lv = lv; | |
271 | ||
272 | /* | |
273 | * If this is the first time the item is being committed to the | |
274 | * CIL, store the sequence number on the log item so we can | |
275 | * tell in future commits whether this is the first checkpoint | |
276 | * the item is being committed into. | |
277 | */ | |
278 | if (!lv->lv_item->li_seq) | |
279 | lv->lv_item->li_seq = log->l_cilp->xc_ctx->sequence; | |
280 | } | |
281 | ||
71e330b5 DC |
282 | /* |
283 | * Format log item into a flat buffers | |
284 | * | |
285 | * For delayed logging, we need to hold a formatted buffer containing all the | |
286 | * changes on the log item. This enables us to relog the item in memory and | |
287 | * write it out asynchronously without needing to relock the object that was | |
288 | * modified at the time it gets written into the iclog. | |
289 | * | |
b1c5ebb2 DC |
290 | * This function takes the prepared log vectors attached to each log item, and |
291 | * formats the changes into the log vector buffer. The buffer it uses is | |
292 | * dependent on the current state of the vector in the CIL - the shadow lv is | |
293 | * guaranteed to be large enough for the current modification, but we will only | |
294 | * use that if we can't reuse the existing lv. If we can't reuse the existing | |
295 | * lv, then simple swap it out for the shadow lv. We don't free it - that is | |
296 | * done lazily either by th enext modification or the freeing of the log item. | |
71e330b5 DC |
297 | * |
298 | * We don't set up region headers during this process; we simply copy the | |
299 | * regions into the flat buffer. We can do this because we still have to do a | |
300 | * formatting step to write the regions into the iclog buffer. Writing the | |
301 | * ophdrs during the iclog write means that we can support splitting large | |
302 | * regions across iclog boundares without needing a change in the format of the | |
303 | * item/region encapsulation. | |
304 | * | |
305 | * Hence what we need to do now is change the rewrite the vector array to point | |
306 | * to the copied region inside the buffer we just allocated. This allows us to | |
307 | * format the regions into the iclog as though they are being formatted | |
308 | * directly out of the objects themselves. | |
309 | */ | |
991aaf65 DC |
310 | static void |
311 | xlog_cil_insert_format_items( | |
312 | struct xlog *log, | |
313 | struct xfs_trans *tp, | |
314 | int *diff_len, | |
315 | int *diff_iovecs) | |
71e330b5 | 316 | { |
0244b960 | 317 | struct xfs_log_item_desc *lidp; |
71e330b5 | 318 | |
0244b960 CH |
319 | |
320 | /* Bail out if we didn't find a log item. */ | |
321 | if (list_empty(&tp->t_items)) { | |
322 | ASSERT(0); | |
991aaf65 | 323 | return; |
0244b960 CH |
324 | } |
325 | ||
326 | list_for_each_entry(lidp, &tp->t_items, lid_trans) { | |
166d1368 | 327 | struct xfs_log_item *lip = lidp->lid_item; |
7492c5b4 | 328 | struct xfs_log_vec *lv; |
b1c5ebb2 DC |
329 | struct xfs_log_vec *old_lv = NULL; |
330 | struct xfs_log_vec *shadow; | |
fd63875c | 331 | bool ordered = false; |
71e330b5 | 332 | |
0244b960 CH |
333 | /* Skip items which aren't dirty in this transaction. */ |
334 | if (!(lidp->lid_flags & XFS_LID_DIRTY)) | |
335 | continue; | |
336 | ||
fd63875c | 337 | /* |
b1c5ebb2 DC |
338 | * The formatting size information is already attached to |
339 | * the shadow lv on the log item. | |
fd63875c | 340 | */ |
b1c5ebb2 DC |
341 | shadow = lip->li_lv_shadow; |
342 | if (shadow->lv_buf_len == XFS_LOG_VEC_ORDERED) | |
fd63875c | 343 | ordered = true; |
fd63875c | 344 | |
b1c5ebb2 DC |
345 | /* Skip items that do not have any vectors for writing */ |
346 | if (!shadow->lv_niovecs && !ordered) | |
347 | continue; | |
0244b960 | 348 | |
f5baac35 | 349 | /* compare to existing item size */ |
b1c5ebb2 DC |
350 | old_lv = lip->li_lv; |
351 | if (lip->li_lv && shadow->lv_size <= lip->li_lv->lv_size) { | |
f5baac35 DC |
352 | /* same or smaller, optimise common overwrite case */ |
353 | lv = lip->li_lv; | |
354 | lv->lv_next = NULL; | |
355 | ||
356 | if (ordered) | |
357 | goto insert; | |
358 | ||
991aaf65 DC |
359 | /* |
360 | * set the item up as though it is a new insertion so | |
361 | * that the space reservation accounting is correct. | |
362 | */ | |
363 | *diff_iovecs -= lv->lv_niovecs; | |
110dc24a | 364 | *diff_len -= lv->lv_bytes; |
b1c5ebb2 DC |
365 | |
366 | /* Ensure the lv is set up according to ->iop_size */ | |
367 | lv->lv_niovecs = shadow->lv_niovecs; | |
368 | ||
369 | /* reset the lv buffer information for new formatting */ | |
370 | lv->lv_buf_len = 0; | |
371 | lv->lv_bytes = 0; | |
372 | lv->lv_buf = (char *)lv + | |
373 | xlog_cil_iovec_space(lv->lv_niovecs); | |
9597df6b | 374 | } else { |
b1c5ebb2 DC |
375 | /* switch to shadow buffer! */ |
376 | lv = shadow; | |
9597df6b | 377 | lv->lv_item = lip; |
9597df6b CH |
378 | if (ordered) { |
379 | /* track as an ordered logvec */ | |
380 | ASSERT(lip->li_lv == NULL); | |
9597df6b CH |
381 | goto insert; |
382 | } | |
f5baac35 DC |
383 | } |
384 | ||
3895e51f | 385 | ASSERT(IS_ALIGNED((unsigned long)lv->lv_buf, sizeof(uint64_t))); |
bde7cff6 | 386 | lip->li_ops->iop_format(lip, lv); |
7492c5b4 | 387 | insert: |
991aaf65 | 388 | xfs_cil_prepare_item(log, lv, old_lv, diff_len, diff_iovecs); |
3b93c7aa | 389 | } |
d1583a38 DC |
390 | } |
391 | ||
392 | /* | |
393 | * Insert the log items into the CIL and calculate the difference in space | |
394 | * consumed by the item. Add the space to the checkpoint ticket and calculate | |
395 | * if the change requires additional log metadata. If it does, take that space | |
42b2aa86 | 396 | * as well. Remove the amount of space we added to the checkpoint ticket from |
d1583a38 DC |
397 | * the current transaction ticket so that the accounting works out correctly. |
398 | */ | |
3b93c7aa DC |
399 | static void |
400 | xlog_cil_insert_items( | |
f7bdf03a | 401 | struct xlog *log, |
991aaf65 | 402 | struct xfs_trans *tp) |
3b93c7aa | 403 | { |
d1583a38 DC |
404 | struct xfs_cil *cil = log->l_cilp; |
405 | struct xfs_cil_ctx *ctx = cil->xc_ctx; | |
991aaf65 | 406 | struct xfs_log_item_desc *lidp; |
d1583a38 DC |
407 | int len = 0; |
408 | int diff_iovecs = 0; | |
409 | int iclog_space; | |
3b93c7aa | 410 | |
991aaf65 | 411 | ASSERT(tp); |
d1583a38 DC |
412 | |
413 | /* | |
d1583a38 DC |
414 | * We can do this safely because the context can't checkpoint until we |
415 | * are done so it doesn't matter exactly how we update the CIL. | |
416 | */ | |
991aaf65 DC |
417 | xlog_cil_insert_format_items(log, tp, &len, &diff_iovecs); |
418 | ||
419 | /* | |
420 | * Now (re-)position everything modified at the tail of the CIL. | |
421 | * We do this here so we only need to take the CIL lock once during | |
422 | * the transaction commit. | |
423 | */ | |
d1583a38 | 424 | spin_lock(&cil->xc_cil_lock); |
991aaf65 DC |
425 | list_for_each_entry(lidp, &tp->t_items, lid_trans) { |
426 | struct xfs_log_item *lip = lidp->lid_item; | |
d1583a38 | 427 | |
991aaf65 DC |
428 | /* Skip items which aren't dirty in this transaction. */ |
429 | if (!(lidp->lid_flags & XFS_LID_DIRTY)) | |
430 | continue; | |
fd63875c | 431 | |
4703da7b BF |
432 | /* |
433 | * Only move the item if it isn't already at the tail. This is | |
434 | * to prevent a transient list_empty() state when reinserting | |
435 | * an item that is already the only item in the CIL. | |
436 | */ | |
437 | if (!list_is_last(&lip->li_cil, &cil->xc_cil)) | |
438 | list_move_tail(&lip->li_cil, &cil->xc_cil); | |
fd63875c | 439 | } |
d1583a38 | 440 | |
fd63875c DC |
441 | /* account for space used by new iovec headers */ |
442 | len += diff_iovecs * sizeof(xlog_op_header_t); | |
d1583a38 DC |
443 | ctx->nvecs += diff_iovecs; |
444 | ||
991aaf65 DC |
445 | /* attach the transaction to the CIL if it has any busy extents */ |
446 | if (!list_empty(&tp->t_busy)) | |
447 | list_splice_init(&tp->t_busy, &ctx->busy_extents); | |
448 | ||
d1583a38 DC |
449 | /* |
450 | * Now transfer enough transaction reservation to the context ticket | |
451 | * for the checkpoint. The context ticket is special - the unit | |
452 | * reservation has to grow as well as the current reservation as we | |
453 | * steal from tickets so we can correctly determine the space used | |
454 | * during the transaction commit. | |
455 | */ | |
456 | if (ctx->ticket->t_curr_res == 0) { | |
d1583a38 | 457 | ctx->ticket->t_curr_res = ctx->ticket->t_unit_res; |
991aaf65 | 458 | tp->t_ticket->t_curr_res -= ctx->ticket->t_unit_res; |
d1583a38 DC |
459 | } |
460 | ||
461 | /* do we need space for more log record headers? */ | |
462 | iclog_space = log->l_iclog_size - log->l_iclog_hsize; | |
463 | if (len > 0 && (ctx->space_used / iclog_space != | |
464 | (ctx->space_used + len) / iclog_space)) { | |
465 | int hdrs; | |
466 | ||
467 | hdrs = (len + iclog_space - 1) / iclog_space; | |
468 | /* need to take into account split region headers, too */ | |
469 | hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header); | |
470 | ctx->ticket->t_unit_res += hdrs; | |
471 | ctx->ticket->t_curr_res += hdrs; | |
991aaf65 DC |
472 | tp->t_ticket->t_curr_res -= hdrs; |
473 | ASSERT(tp->t_ticket->t_curr_res >= len); | |
d1583a38 | 474 | } |
991aaf65 | 475 | tp->t_ticket->t_curr_res -= len; |
d1583a38 DC |
476 | ctx->space_used += len; |
477 | ||
478 | spin_unlock(&cil->xc_cil_lock); | |
71e330b5 DC |
479 | } |
480 | ||
481 | static void | |
482 | xlog_cil_free_logvec( | |
483 | struct xfs_log_vec *log_vector) | |
484 | { | |
485 | struct xfs_log_vec *lv; | |
486 | ||
487 | for (lv = log_vector; lv; ) { | |
488 | struct xfs_log_vec *next = lv->lv_next; | |
71e330b5 DC |
489 | kmem_free(lv); |
490 | lv = next; | |
491 | } | |
492 | } | |
493 | ||
71e330b5 DC |
494 | /* |
495 | * Mark all items committed and clear busy extents. We free the log vector | |
496 | * chains in a separate pass so that we unpin the log items as quickly as | |
497 | * possible. | |
498 | */ | |
499 | static void | |
500 | xlog_cil_committed( | |
501 | void *args, | |
502 | int abort) | |
503 | { | |
504 | struct xfs_cil_ctx *ctx = args; | |
e84661aa | 505 | struct xfs_mount *mp = ctx->cil->xc_log->l_mp; |
71e330b5 | 506 | |
0e57f6a3 DC |
507 | xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, ctx->lv_chain, |
508 | ctx->start_lsn, abort); | |
71e330b5 | 509 | |
4ecbfe63 DC |
510 | xfs_extent_busy_sort(&ctx->busy_extents); |
511 | xfs_extent_busy_clear(mp, &ctx->busy_extents, | |
e84661aa | 512 | (mp->m_flags & XFS_MOUNT_DISCARD) && !abort); |
71e330b5 | 513 | |
ac983517 DC |
514 | /* |
515 | * If we are aborting the commit, wake up anyone waiting on the | |
516 | * committing list. If we don't, then a shutdown we can leave processes | |
517 | * waiting in xlog_cil_force_lsn() waiting on a sequence commit that | |
518 | * will never happen because we aborted it. | |
519 | */ | |
4bb928cd | 520 | spin_lock(&ctx->cil->xc_push_lock); |
ac983517 DC |
521 | if (abort) |
522 | wake_up_all(&ctx->cil->xc_commit_wait); | |
71e330b5 | 523 | list_del(&ctx->committing); |
4bb928cd | 524 | spin_unlock(&ctx->cil->xc_push_lock); |
71e330b5 DC |
525 | |
526 | xlog_cil_free_logvec(ctx->lv_chain); | |
e84661aa CH |
527 | |
528 | if (!list_empty(&ctx->busy_extents)) { | |
529 | ASSERT(mp->m_flags & XFS_MOUNT_DISCARD); | |
530 | ||
531 | xfs_discard_extents(mp, &ctx->busy_extents); | |
4ecbfe63 | 532 | xfs_extent_busy_clear(mp, &ctx->busy_extents, false); |
e84661aa CH |
533 | } |
534 | ||
71e330b5 DC |
535 | kmem_free(ctx); |
536 | } | |
537 | ||
538 | /* | |
a44f13ed DC |
539 | * Push the Committed Item List to the log. If @push_seq flag is zero, then it |
540 | * is a background flush and so we can chose to ignore it. Otherwise, if the | |
541 | * current sequence is the same as @push_seq we need to do a flush. If | |
542 | * @push_seq is less than the current sequence, then it has already been | |
543 | * flushed and we don't need to do anything - the caller will wait for it to | |
544 | * complete if necessary. | |
545 | * | |
546 | * @push_seq is a value rather than a flag because that allows us to do an | |
547 | * unlocked check of the sequence number for a match. Hence we can allows log | |
548 | * forces to run racily and not issue pushes for the same sequence twice. If we | |
549 | * get a race between multiple pushes for the same sequence they will block on | |
550 | * the first one and then abort, hence avoiding needless pushes. | |
71e330b5 | 551 | */ |
a44f13ed | 552 | STATIC int |
71e330b5 | 553 | xlog_cil_push( |
f7bdf03a | 554 | struct xlog *log) |
71e330b5 DC |
555 | { |
556 | struct xfs_cil *cil = log->l_cilp; | |
557 | struct xfs_log_vec *lv; | |
558 | struct xfs_cil_ctx *ctx; | |
559 | struct xfs_cil_ctx *new_ctx; | |
560 | struct xlog_in_core *commit_iclog; | |
561 | struct xlog_ticket *tic; | |
71e330b5 | 562 | int num_iovecs; |
71e330b5 DC |
563 | int error = 0; |
564 | struct xfs_trans_header thdr; | |
565 | struct xfs_log_iovec lhdr; | |
566 | struct xfs_log_vec lvhdr = { NULL }; | |
567 | xfs_lsn_t commit_lsn; | |
4c2d542f | 568 | xfs_lsn_t push_seq; |
71e330b5 DC |
569 | |
570 | if (!cil) | |
571 | return 0; | |
572 | ||
71e330b5 DC |
573 | new_ctx = kmem_zalloc(sizeof(*new_ctx), KM_SLEEP|KM_NOFS); |
574 | new_ctx->ticket = xlog_cil_ticket_alloc(log); | |
575 | ||
4c2d542f | 576 | down_write(&cil->xc_ctx_lock); |
71e330b5 DC |
577 | ctx = cil->xc_ctx; |
578 | ||
4bb928cd | 579 | spin_lock(&cil->xc_push_lock); |
4c2d542f DC |
580 | push_seq = cil->xc_push_seq; |
581 | ASSERT(push_seq <= ctx->sequence); | |
71e330b5 | 582 | |
4c2d542f DC |
583 | /* |
584 | * Check if we've anything to push. If there is nothing, then we don't | |
585 | * move on to a new sequence number and so we have to be able to push | |
586 | * this sequence again later. | |
587 | */ | |
588 | if (list_empty(&cil->xc_cil)) { | |
589 | cil->xc_push_seq = 0; | |
4bb928cd | 590 | spin_unlock(&cil->xc_push_lock); |
a44f13ed | 591 | goto out_skip; |
4c2d542f | 592 | } |
4c2d542f | 593 | |
a44f13ed DC |
594 | |
595 | /* check for a previously pushed seqeunce */ | |
8af3dcd3 DC |
596 | if (push_seq < cil->xc_ctx->sequence) { |
597 | spin_unlock(&cil->xc_push_lock); | |
df806158 | 598 | goto out_skip; |
8af3dcd3 DC |
599 | } |
600 | ||
601 | /* | |
602 | * We are now going to push this context, so add it to the committing | |
603 | * list before we do anything else. This ensures that anyone waiting on | |
604 | * this push can easily detect the difference between a "push in | |
605 | * progress" and "CIL is empty, nothing to do". | |
606 | * | |
607 | * IOWs, a wait loop can now check for: | |
608 | * the current sequence not being found on the committing list; | |
609 | * an empty CIL; and | |
610 | * an unchanged sequence number | |
611 | * to detect a push that had nothing to do and therefore does not need | |
612 | * waiting on. If the CIL is not empty, we get put on the committing | |
613 | * list before emptying the CIL and bumping the sequence number. Hence | |
614 | * an empty CIL and an unchanged sequence number means we jumped out | |
615 | * above after doing nothing. | |
616 | * | |
617 | * Hence the waiter will either find the commit sequence on the | |
618 | * committing list or the sequence number will be unchanged and the CIL | |
619 | * still dirty. In that latter case, the push has not yet started, and | |
620 | * so the waiter will have to continue trying to check the CIL | |
621 | * committing list until it is found. In extreme cases of delay, the | |
622 | * sequence may fully commit between the attempts the wait makes to wait | |
623 | * on the commit sequence. | |
624 | */ | |
625 | list_add(&ctx->committing, &cil->xc_committing); | |
626 | spin_unlock(&cil->xc_push_lock); | |
df806158 | 627 | |
71e330b5 DC |
628 | /* |
629 | * pull all the log vectors off the items in the CIL, and | |
630 | * remove the items from the CIL. We don't need the CIL lock | |
631 | * here because it's only needed on the transaction commit | |
632 | * side which is currently locked out by the flush lock. | |
633 | */ | |
634 | lv = NULL; | |
71e330b5 | 635 | num_iovecs = 0; |
71e330b5 DC |
636 | while (!list_empty(&cil->xc_cil)) { |
637 | struct xfs_log_item *item; | |
71e330b5 DC |
638 | |
639 | item = list_first_entry(&cil->xc_cil, | |
640 | struct xfs_log_item, li_cil); | |
641 | list_del_init(&item->li_cil); | |
642 | if (!ctx->lv_chain) | |
643 | ctx->lv_chain = item->li_lv; | |
644 | else | |
645 | lv->lv_next = item->li_lv; | |
646 | lv = item->li_lv; | |
647 | item->li_lv = NULL; | |
71e330b5 | 648 | num_iovecs += lv->lv_niovecs; |
71e330b5 DC |
649 | } |
650 | ||
651 | /* | |
652 | * initialise the new context and attach it to the CIL. Then attach | |
653 | * the current context to the CIL committing lsit so it can be found | |
654 | * during log forces to extract the commit lsn of the sequence that | |
655 | * needs to be forced. | |
656 | */ | |
657 | INIT_LIST_HEAD(&new_ctx->committing); | |
658 | INIT_LIST_HEAD(&new_ctx->busy_extents); | |
659 | new_ctx->sequence = ctx->sequence + 1; | |
660 | new_ctx->cil = cil; | |
661 | cil->xc_ctx = new_ctx; | |
662 | ||
663 | /* | |
664 | * The switch is now done, so we can drop the context lock and move out | |
665 | * of a shared context. We can't just go straight to the commit record, | |
666 | * though - we need to synchronise with previous and future commits so | |
667 | * that the commit records are correctly ordered in the log to ensure | |
668 | * that we process items during log IO completion in the correct order. | |
669 | * | |
670 | * For example, if we get an EFI in one checkpoint and the EFD in the | |
671 | * next (e.g. due to log forces), we do not want the checkpoint with | |
672 | * the EFD to be committed before the checkpoint with the EFI. Hence | |
673 | * we must strictly order the commit records of the checkpoints so | |
674 | * that: a) the checkpoint callbacks are attached to the iclogs in the | |
675 | * correct order; and b) the checkpoints are replayed in correct order | |
676 | * in log recovery. | |
677 | * | |
678 | * Hence we need to add this context to the committing context list so | |
679 | * that higher sequences will wait for us to write out a commit record | |
680 | * before they do. | |
f876e446 DC |
681 | * |
682 | * xfs_log_force_lsn requires us to mirror the new sequence into the cil | |
683 | * structure atomically with the addition of this sequence to the | |
684 | * committing list. This also ensures that we can do unlocked checks | |
685 | * against the current sequence in log forces without risking | |
686 | * deferencing a freed context pointer. | |
71e330b5 | 687 | */ |
4bb928cd | 688 | spin_lock(&cil->xc_push_lock); |
f876e446 | 689 | cil->xc_current_sequence = new_ctx->sequence; |
4bb928cd | 690 | spin_unlock(&cil->xc_push_lock); |
71e330b5 DC |
691 | up_write(&cil->xc_ctx_lock); |
692 | ||
693 | /* | |
694 | * Build a checkpoint transaction header and write it to the log to | |
695 | * begin the transaction. We need to account for the space used by the | |
696 | * transaction header here as it is not accounted for in xlog_write(). | |
697 | * | |
698 | * The LSN we need to pass to the log items on transaction commit is | |
699 | * the LSN reported by the first log vector write. If we use the commit | |
700 | * record lsn then we can move the tail beyond the grant write head. | |
701 | */ | |
702 | tic = ctx->ticket; | |
703 | thdr.th_magic = XFS_TRANS_HEADER_MAGIC; | |
704 | thdr.th_type = XFS_TRANS_CHECKPOINT; | |
705 | thdr.th_tid = tic->t_tid; | |
706 | thdr.th_num_items = num_iovecs; | |
4e0d5f92 | 707 | lhdr.i_addr = &thdr; |
71e330b5 DC |
708 | lhdr.i_len = sizeof(xfs_trans_header_t); |
709 | lhdr.i_type = XLOG_REG_TYPE_TRANSHDR; | |
710 | tic->t_curr_res -= lhdr.i_len + sizeof(xlog_op_header_t); | |
711 | ||
712 | lvhdr.lv_niovecs = 1; | |
713 | lvhdr.lv_iovecp = &lhdr; | |
714 | lvhdr.lv_next = ctx->lv_chain; | |
715 | ||
716 | error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0); | |
717 | if (error) | |
7db37c5e | 718 | goto out_abort_free_ticket; |
71e330b5 DC |
719 | |
720 | /* | |
721 | * now that we've written the checkpoint into the log, strictly | |
722 | * order the commit records so replay will get them in the right order. | |
723 | */ | |
724 | restart: | |
4bb928cd | 725 | spin_lock(&cil->xc_push_lock); |
71e330b5 | 726 | list_for_each_entry(new_ctx, &cil->xc_committing, committing) { |
ac983517 DC |
727 | /* |
728 | * Avoid getting stuck in this loop because we were woken by the | |
729 | * shutdown, but then went back to sleep once already in the | |
730 | * shutdown state. | |
731 | */ | |
732 | if (XLOG_FORCED_SHUTDOWN(log)) { | |
733 | spin_unlock(&cil->xc_push_lock); | |
734 | goto out_abort_free_ticket; | |
735 | } | |
736 | ||
71e330b5 DC |
737 | /* |
738 | * Higher sequences will wait for this one so skip them. | |
ac983517 | 739 | * Don't wait for our own sequence, either. |
71e330b5 DC |
740 | */ |
741 | if (new_ctx->sequence >= ctx->sequence) | |
742 | continue; | |
743 | if (!new_ctx->commit_lsn) { | |
744 | /* | |
745 | * It is still being pushed! Wait for the push to | |
746 | * complete, then start again from the beginning. | |
747 | */ | |
4bb928cd | 748 | xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock); |
71e330b5 DC |
749 | goto restart; |
750 | } | |
751 | } | |
4bb928cd | 752 | spin_unlock(&cil->xc_push_lock); |
71e330b5 | 753 | |
7db37c5e | 754 | /* xfs_log_done always frees the ticket on error. */ |
f78c3901 | 755 | commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, false); |
7db37c5e | 756 | if (commit_lsn == -1) |
71e330b5 DC |
757 | goto out_abort; |
758 | ||
759 | /* attach all the transactions w/ busy extents to iclog */ | |
760 | ctx->log_cb.cb_func = xlog_cil_committed; | |
761 | ctx->log_cb.cb_arg = ctx; | |
762 | error = xfs_log_notify(log->l_mp, commit_iclog, &ctx->log_cb); | |
763 | if (error) | |
764 | goto out_abort; | |
765 | ||
766 | /* | |
767 | * now the checkpoint commit is complete and we've attached the | |
768 | * callbacks to the iclog we can assign the commit LSN to the context | |
769 | * and wake up anyone who is waiting for the commit to complete. | |
770 | */ | |
4bb928cd | 771 | spin_lock(&cil->xc_push_lock); |
71e330b5 | 772 | ctx->commit_lsn = commit_lsn; |
eb40a875 | 773 | wake_up_all(&cil->xc_commit_wait); |
4bb928cd | 774 | spin_unlock(&cil->xc_push_lock); |
71e330b5 DC |
775 | |
776 | /* release the hounds! */ | |
777 | return xfs_log_release_iclog(log->l_mp, commit_iclog); | |
778 | ||
779 | out_skip: | |
780 | up_write(&cil->xc_ctx_lock); | |
781 | xfs_log_ticket_put(new_ctx->ticket); | |
782 | kmem_free(new_ctx); | |
783 | return 0; | |
784 | ||
7db37c5e DC |
785 | out_abort_free_ticket: |
786 | xfs_log_ticket_put(tic); | |
71e330b5 DC |
787 | out_abort: |
788 | xlog_cil_committed(ctx, XFS_LI_ABORTED); | |
2451337d | 789 | return -EIO; |
71e330b5 DC |
790 | } |
791 | ||
4c2d542f DC |
792 | static void |
793 | xlog_cil_push_work( | |
794 | struct work_struct *work) | |
795 | { | |
796 | struct xfs_cil *cil = container_of(work, struct xfs_cil, | |
797 | xc_push_work); | |
798 | xlog_cil_push(cil->xc_log); | |
799 | } | |
800 | ||
801 | /* | |
802 | * We need to push CIL every so often so we don't cache more than we can fit in | |
803 | * the log. The limit really is that a checkpoint can't be more than half the | |
804 | * log (the current checkpoint is not allowed to overwrite the previous | |
805 | * checkpoint), but commit latency and memory usage limit this to a smaller | |
806 | * size. | |
807 | */ | |
808 | static void | |
809 | xlog_cil_push_background( | |
f7bdf03a | 810 | struct xlog *log) |
4c2d542f DC |
811 | { |
812 | struct xfs_cil *cil = log->l_cilp; | |
813 | ||
814 | /* | |
815 | * The cil won't be empty because we are called while holding the | |
816 | * context lock so whatever we added to the CIL will still be there | |
817 | */ | |
818 | ASSERT(!list_empty(&cil->xc_cil)); | |
819 | ||
820 | /* | |
821 | * don't do a background push if we haven't used up all the | |
822 | * space available yet. | |
823 | */ | |
824 | if (cil->xc_ctx->space_used < XLOG_CIL_SPACE_LIMIT(log)) | |
825 | return; | |
826 | ||
4bb928cd | 827 | spin_lock(&cil->xc_push_lock); |
4c2d542f DC |
828 | if (cil->xc_push_seq < cil->xc_current_sequence) { |
829 | cil->xc_push_seq = cil->xc_current_sequence; | |
830 | queue_work(log->l_mp->m_cil_workqueue, &cil->xc_push_work); | |
831 | } | |
4bb928cd | 832 | spin_unlock(&cil->xc_push_lock); |
4c2d542f DC |
833 | |
834 | } | |
835 | ||
f876e446 DC |
836 | /* |
837 | * xlog_cil_push_now() is used to trigger an immediate CIL push to the sequence | |
838 | * number that is passed. When it returns, the work will be queued for | |
839 | * @push_seq, but it won't be completed. The caller is expected to do any | |
840 | * waiting for push_seq to complete if it is required. | |
841 | */ | |
4c2d542f | 842 | static void |
f876e446 | 843 | xlog_cil_push_now( |
f7bdf03a | 844 | struct xlog *log, |
4c2d542f DC |
845 | xfs_lsn_t push_seq) |
846 | { | |
847 | struct xfs_cil *cil = log->l_cilp; | |
848 | ||
849 | if (!cil) | |
850 | return; | |
851 | ||
852 | ASSERT(push_seq && push_seq <= cil->xc_current_sequence); | |
853 | ||
854 | /* start on any pending background push to minimise wait time on it */ | |
855 | flush_work(&cil->xc_push_work); | |
856 | ||
857 | /* | |
858 | * If the CIL is empty or we've already pushed the sequence then | |
859 | * there's no work we need to do. | |
860 | */ | |
4bb928cd | 861 | spin_lock(&cil->xc_push_lock); |
4c2d542f | 862 | if (list_empty(&cil->xc_cil) || push_seq <= cil->xc_push_seq) { |
4bb928cd | 863 | spin_unlock(&cil->xc_push_lock); |
4c2d542f DC |
864 | return; |
865 | } | |
866 | ||
867 | cil->xc_push_seq = push_seq; | |
f876e446 | 868 | queue_work(log->l_mp->m_cil_workqueue, &cil->xc_push_work); |
4bb928cd | 869 | spin_unlock(&cil->xc_push_lock); |
4c2d542f DC |
870 | } |
871 | ||
2c6e24ce DC |
872 | bool |
873 | xlog_cil_empty( | |
874 | struct xlog *log) | |
875 | { | |
876 | struct xfs_cil *cil = log->l_cilp; | |
877 | bool empty = false; | |
878 | ||
879 | spin_lock(&cil->xc_push_lock); | |
880 | if (list_empty(&cil->xc_cil)) | |
881 | empty = true; | |
882 | spin_unlock(&cil->xc_push_lock); | |
883 | return empty; | |
884 | } | |
885 | ||
a44f13ed DC |
886 | /* |
887 | * Commit a transaction with the given vector to the Committed Item List. | |
888 | * | |
889 | * To do this, we need to format the item, pin it in memory if required and | |
890 | * account for the space used by the transaction. Once we have done that we | |
891 | * need to release the unused reservation for the transaction, attach the | |
892 | * transaction to the checkpoint context so we carry the busy extents through | |
893 | * to checkpoint completion, and then unlock all the items in the transaction. | |
894 | * | |
a44f13ed DC |
895 | * Called with the context lock already held in read mode to lock out |
896 | * background commit, returns without it held once background commits are | |
897 | * allowed again. | |
898 | */ | |
c6f97264 | 899 | void |
a44f13ed DC |
900 | xfs_log_commit_cil( |
901 | struct xfs_mount *mp, | |
902 | struct xfs_trans *tp, | |
a44f13ed | 903 | xfs_lsn_t *commit_lsn, |
70393313 | 904 | bool regrant) |
a44f13ed | 905 | { |
f7bdf03a | 906 | struct xlog *log = mp->m_log; |
991aaf65 | 907 | struct xfs_cil *cil = log->l_cilp; |
a44f13ed | 908 | |
b1c5ebb2 DC |
909 | /* |
910 | * Do all necessary memory allocation before we lock the CIL. | |
911 | * This ensures the allocation does not deadlock with a CIL | |
912 | * push in memory reclaim (e.g. from kswapd). | |
913 | */ | |
914 | xlog_cil_alloc_shadow_bufs(log, tp); | |
915 | ||
f5baac35 | 916 | /* lock out background commit */ |
991aaf65 | 917 | down_read(&cil->xc_ctx_lock); |
f5baac35 | 918 | |
991aaf65 | 919 | xlog_cil_insert_items(log, tp); |
a44f13ed DC |
920 | |
921 | /* check we didn't blow the reservation */ | |
922 | if (tp->t_ticket->t_curr_res < 0) | |
991aaf65 | 923 | xlog_print_tic_res(mp, tp->t_ticket); |
a44f13ed | 924 | |
991aaf65 DC |
925 | tp->t_commit_lsn = cil->xc_ctx->sequence; |
926 | if (commit_lsn) | |
927 | *commit_lsn = tp->t_commit_lsn; | |
a44f13ed | 928 | |
f78c3901 | 929 | xfs_log_done(mp, tp->t_ticket, NULL, regrant); |
a44f13ed DC |
930 | xfs_trans_unreserve_and_mod_sb(tp); |
931 | ||
932 | /* | |
933 | * Once all the items of the transaction have been copied to the CIL, | |
934 | * the items can be unlocked and freed. | |
935 | * | |
936 | * This needs to be done before we drop the CIL context lock because we | |
937 | * have to update state in the log items and unlock them before they go | |
938 | * to disk. If we don't, then the CIL checkpoint can race with us and | |
939 | * we can run checkpoint completion before we've updated and unlocked | |
940 | * the log items. This affects (at least) processing of stale buffers, | |
941 | * inodes and EFIs. | |
942 | */ | |
eacb24e7 | 943 | xfs_trans_free_items(tp, tp->t_commit_lsn, false); |
a44f13ed | 944 | |
4c2d542f | 945 | xlog_cil_push_background(log); |
a44f13ed | 946 | |
991aaf65 | 947 | up_read(&cil->xc_ctx_lock); |
a44f13ed DC |
948 | } |
949 | ||
71e330b5 DC |
950 | /* |
951 | * Conditionally push the CIL based on the sequence passed in. | |
952 | * | |
953 | * We only need to push if we haven't already pushed the sequence | |
954 | * number given. Hence the only time we will trigger a push here is | |
955 | * if the push sequence is the same as the current context. | |
956 | * | |
957 | * We return the current commit lsn to allow the callers to determine if a | |
958 | * iclog flush is necessary following this call. | |
71e330b5 DC |
959 | */ |
960 | xfs_lsn_t | |
a44f13ed | 961 | xlog_cil_force_lsn( |
f7bdf03a | 962 | struct xlog *log, |
a44f13ed | 963 | xfs_lsn_t sequence) |
71e330b5 DC |
964 | { |
965 | struct xfs_cil *cil = log->l_cilp; | |
966 | struct xfs_cil_ctx *ctx; | |
967 | xfs_lsn_t commit_lsn = NULLCOMMITLSN; | |
968 | ||
a44f13ed DC |
969 | ASSERT(sequence <= cil->xc_current_sequence); |
970 | ||
971 | /* | |
972 | * check to see if we need to force out the current context. | |
973 | * xlog_cil_push() handles racing pushes for the same sequence, | |
974 | * so no need to deal with it here. | |
975 | */ | |
f876e446 DC |
976 | restart: |
977 | xlog_cil_push_now(log, sequence); | |
71e330b5 DC |
978 | |
979 | /* | |
980 | * See if we can find a previous sequence still committing. | |
71e330b5 DC |
981 | * We need to wait for all previous sequence commits to complete |
982 | * before allowing the force of push_seq to go ahead. Hence block | |
983 | * on commits for those as well. | |
984 | */ | |
4bb928cd | 985 | spin_lock(&cil->xc_push_lock); |
71e330b5 | 986 | list_for_each_entry(ctx, &cil->xc_committing, committing) { |
ac983517 DC |
987 | /* |
988 | * Avoid getting stuck in this loop because we were woken by the | |
989 | * shutdown, but then went back to sleep once already in the | |
990 | * shutdown state. | |
991 | */ | |
992 | if (XLOG_FORCED_SHUTDOWN(log)) | |
993 | goto out_shutdown; | |
a44f13ed | 994 | if (ctx->sequence > sequence) |
71e330b5 DC |
995 | continue; |
996 | if (!ctx->commit_lsn) { | |
997 | /* | |
998 | * It is still being pushed! Wait for the push to | |
999 | * complete, then start again from the beginning. | |
1000 | */ | |
4bb928cd | 1001 | xlog_wait(&cil->xc_commit_wait, &cil->xc_push_lock); |
71e330b5 DC |
1002 | goto restart; |
1003 | } | |
a44f13ed | 1004 | if (ctx->sequence != sequence) |
71e330b5 DC |
1005 | continue; |
1006 | /* found it! */ | |
1007 | commit_lsn = ctx->commit_lsn; | |
1008 | } | |
f876e446 DC |
1009 | |
1010 | /* | |
1011 | * The call to xlog_cil_push_now() executes the push in the background. | |
1012 | * Hence by the time we have got here it our sequence may not have been | |
1013 | * pushed yet. This is true if the current sequence still matches the | |
1014 | * push sequence after the above wait loop and the CIL still contains | |
8af3dcd3 DC |
1015 | * dirty objects. This is guaranteed by the push code first adding the |
1016 | * context to the committing list before emptying the CIL. | |
f876e446 | 1017 | * |
8af3dcd3 DC |
1018 | * Hence if we don't find the context in the committing list and the |
1019 | * current sequence number is unchanged then the CIL contents are | |
1020 | * significant. If the CIL is empty, if means there was nothing to push | |
1021 | * and that means there is nothing to wait for. If the CIL is not empty, | |
1022 | * it means we haven't yet started the push, because if it had started | |
1023 | * we would have found the context on the committing list. | |
f876e446 | 1024 | */ |
f876e446 DC |
1025 | if (sequence == cil->xc_current_sequence && |
1026 | !list_empty(&cil->xc_cil)) { | |
1027 | spin_unlock(&cil->xc_push_lock); | |
1028 | goto restart; | |
1029 | } | |
1030 | ||
4bb928cd | 1031 | spin_unlock(&cil->xc_push_lock); |
71e330b5 | 1032 | return commit_lsn; |
ac983517 DC |
1033 | |
1034 | /* | |
1035 | * We detected a shutdown in progress. We need to trigger the log force | |
1036 | * to pass through it's iclog state machine error handling, even though | |
1037 | * we are already in a shutdown state. Hence we can't return | |
1038 | * NULLCOMMITLSN here as that has special meaning to log forces (i.e. | |
1039 | * LSN is already stable), so we return a zero LSN instead. | |
1040 | */ | |
1041 | out_shutdown: | |
1042 | spin_unlock(&cil->xc_push_lock); | |
1043 | return 0; | |
71e330b5 | 1044 | } |
ccf7c23f DC |
1045 | |
1046 | /* | |
1047 | * Check if the current log item was first committed in this sequence. | |
1048 | * We can't rely on just the log item being in the CIL, we have to check | |
1049 | * the recorded commit sequence number. | |
1050 | * | |
1051 | * Note: for this to be used in a non-racy manner, it has to be called with | |
1052 | * CIL flushing locked out. As a result, it should only be used during the | |
1053 | * transaction commit process when deciding what to format into the item. | |
1054 | */ | |
1055 | bool | |
1056 | xfs_log_item_in_current_chkpt( | |
1057 | struct xfs_log_item *lip) | |
1058 | { | |
1059 | struct xfs_cil_ctx *ctx; | |
1060 | ||
ccf7c23f DC |
1061 | if (list_empty(&lip->li_cil)) |
1062 | return false; | |
1063 | ||
1064 | ctx = lip->li_mountp->m_log->l_cilp->xc_ctx; | |
1065 | ||
1066 | /* | |
1067 | * li_seq is written on the first commit of a log item to record the | |
1068 | * first checkpoint it is written to. Hence if it is different to the | |
1069 | * current sequence, we're in a new checkpoint. | |
1070 | */ | |
1071 | if (XFS_LSN_CMP(lip->li_seq, ctx->sequence) != 0) | |
1072 | return false; | |
1073 | return true; | |
1074 | } | |
4c2d542f DC |
1075 | |
1076 | /* | |
1077 | * Perform initial CIL structure initialisation. | |
1078 | */ | |
1079 | int | |
1080 | xlog_cil_init( | |
f7bdf03a | 1081 | struct xlog *log) |
4c2d542f DC |
1082 | { |
1083 | struct xfs_cil *cil; | |
1084 | struct xfs_cil_ctx *ctx; | |
1085 | ||
1086 | cil = kmem_zalloc(sizeof(*cil), KM_SLEEP|KM_MAYFAIL); | |
1087 | if (!cil) | |
2451337d | 1088 | return -ENOMEM; |
4c2d542f DC |
1089 | |
1090 | ctx = kmem_zalloc(sizeof(*ctx), KM_SLEEP|KM_MAYFAIL); | |
1091 | if (!ctx) { | |
1092 | kmem_free(cil); | |
2451337d | 1093 | return -ENOMEM; |
4c2d542f DC |
1094 | } |
1095 | ||
1096 | INIT_WORK(&cil->xc_push_work, xlog_cil_push_work); | |
1097 | INIT_LIST_HEAD(&cil->xc_cil); | |
1098 | INIT_LIST_HEAD(&cil->xc_committing); | |
1099 | spin_lock_init(&cil->xc_cil_lock); | |
4bb928cd | 1100 | spin_lock_init(&cil->xc_push_lock); |
4c2d542f DC |
1101 | init_rwsem(&cil->xc_ctx_lock); |
1102 | init_waitqueue_head(&cil->xc_commit_wait); | |
1103 | ||
1104 | INIT_LIST_HEAD(&ctx->committing); | |
1105 | INIT_LIST_HEAD(&ctx->busy_extents); | |
1106 | ctx->sequence = 1; | |
1107 | ctx->cil = cil; | |
1108 | cil->xc_ctx = ctx; | |
1109 | cil->xc_current_sequence = ctx->sequence; | |
1110 | ||
1111 | cil->xc_log = log; | |
1112 | log->l_cilp = cil; | |
1113 | return 0; | |
1114 | } | |
1115 | ||
1116 | void | |
1117 | xlog_cil_destroy( | |
f7bdf03a | 1118 | struct xlog *log) |
4c2d542f DC |
1119 | { |
1120 | if (log->l_cilp->xc_ctx) { | |
1121 | if (log->l_cilp->xc_ctx->ticket) | |
1122 | xfs_log_ticket_put(log->l_cilp->xc_ctx->ticket); | |
1123 | kmem_free(log->l_cilp->xc_ctx); | |
1124 | } | |
1125 | ||
1126 | ASSERT(list_empty(&log->l_cilp->xc_cil)); | |
1127 | kmem_free(log->l_cilp); | |
1128 | } | |
1129 |