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470decc6 | 1 | /* |
58862699 | 2 | * linux/fs/jbd2/transaction.c |
470decc6 DK |
3 | * |
4 | * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 | |
5 | * | |
6 | * Copyright 1998 Red Hat corp --- All Rights Reserved | |
7 | * | |
8 | * This file is part of the Linux kernel and is made available under | |
9 | * the terms of the GNU General Public License, version 2, or at your | |
10 | * option, any later version, incorporated herein by reference. | |
11 | * | |
12 | * Generic filesystem transaction handling code; part of the ext2fs | |
13 | * journaling system. | |
14 | * | |
15 | * This file manages transactions (compound commits managed by the | |
16 | * journaling code) and handles (individual atomic operations by the | |
17 | * filesystem). | |
18 | */ | |
19 | ||
20 | #include <linux/time.h> | |
21 | #include <linux/fs.h> | |
f7f4bccb | 22 | #include <linux/jbd2.h> |
470decc6 DK |
23 | #include <linux/errno.h> |
24 | #include <linux/slab.h> | |
25 | #include <linux/timer.h> | |
470decc6 DK |
26 | #include <linux/mm.h> |
27 | #include <linux/highmem.h> | |
e07f7183 | 28 | #include <linux/hrtimer.h> |
47def826 | 29 | #include <linux/backing-dev.h> |
44705754 | 30 | #include <linux/bug.h> |
47def826 | 31 | #include <linux/module.h> |
470decc6 | 32 | |
7ddae860 | 33 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
de1b7941 | 34 | static void __jbd2_journal_unfile_buffer(struct journal_head *jh); |
7ddae860 | 35 | |
0c2022ec YY |
36 | static struct kmem_cache *transaction_cache; |
37 | int __init jbd2_journal_init_transaction_cache(void) | |
38 | { | |
39 | J_ASSERT(!transaction_cache); | |
40 | transaction_cache = kmem_cache_create("jbd2_transaction_s", | |
41 | sizeof(transaction_t), | |
42 | 0, | |
43 | SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY, | |
44 | NULL); | |
45 | if (transaction_cache) | |
46 | return 0; | |
47 | return -ENOMEM; | |
48 | } | |
49 | ||
50 | void jbd2_journal_destroy_transaction_cache(void) | |
51 | { | |
52 | if (transaction_cache) { | |
53 | kmem_cache_destroy(transaction_cache); | |
54 | transaction_cache = NULL; | |
55 | } | |
56 | } | |
57 | ||
58 | void jbd2_journal_free_transaction(transaction_t *transaction) | |
59 | { | |
60 | if (unlikely(ZERO_OR_NULL_PTR(transaction))) | |
61 | return; | |
62 | kmem_cache_free(transaction_cache, transaction); | |
63 | } | |
64 | ||
470decc6 | 65 | /* |
f7f4bccb | 66 | * jbd2_get_transaction: obtain a new transaction_t object. |
470decc6 DK |
67 | * |
68 | * Simply allocate and initialise a new transaction. Create it in | |
69 | * RUNNING state and add it to the current journal (which should not | |
70 | * have an existing running transaction: we only make a new transaction | |
71 | * once we have started to commit the old one). | |
72 | * | |
73 | * Preconditions: | |
74 | * The journal MUST be locked. We don't perform atomic mallocs on the | |
75 | * new transaction and we can't block without protecting against other | |
76 | * processes trying to touch the journal while it is in transition. | |
77 | * | |
470decc6 DK |
78 | */ |
79 | ||
80 | static transaction_t * | |
f7f4bccb | 81 | jbd2_get_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
82 | { |
83 | transaction->t_journal = journal; | |
84 | transaction->t_state = T_RUNNING; | |
e07f7183 | 85 | transaction->t_start_time = ktime_get(); |
470decc6 DK |
86 | transaction->t_tid = journal->j_transaction_sequence++; |
87 | transaction->t_expires = jiffies + journal->j_commit_interval; | |
88 | spin_lock_init(&transaction->t_handle_lock); | |
a51dca9c TT |
89 | atomic_set(&transaction->t_updates, 0); |
90 | atomic_set(&transaction->t_outstanding_credits, 0); | |
8dd42046 | 91 | atomic_set(&transaction->t_handle_count, 0); |
c851ed54 | 92 | INIT_LIST_HEAD(&transaction->t_inode_list); |
3e624fc7 | 93 | INIT_LIST_HEAD(&transaction->t_private_list); |
470decc6 DK |
94 | |
95 | /* Set up the commit timer for the new transaction. */ | |
b1f485f2 | 96 | journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
470decc6 DK |
97 | add_timer(&journal->j_commit_timer); |
98 | ||
99 | J_ASSERT(journal->j_running_transaction == NULL); | |
100 | journal->j_running_transaction = transaction; | |
8e85fb3f JL |
101 | transaction->t_max_wait = 0; |
102 | transaction->t_start = jiffies; | |
470decc6 DK |
103 | |
104 | return transaction; | |
105 | } | |
106 | ||
107 | /* | |
108 | * Handle management. | |
109 | * | |
110 | * A handle_t is an object which represents a single atomic update to a | |
111 | * filesystem, and which tracks all of the modifications which form part | |
112 | * of that one update. | |
113 | */ | |
114 | ||
6d0bf005 | 115 | /* |
28e35e42 | 116 | * Update transaction's maximum wait time, if debugging is enabled. |
6d0bf005 TT |
117 | * |
118 | * In order for t_max_wait to be reliable, it must be protected by a | |
119 | * lock. But doing so will mean that start_this_handle() can not be | |
120 | * run in parallel on SMP systems, which limits our scalability. So | |
121 | * unless debugging is enabled, we no longer update t_max_wait, which | |
122 | * means that maximum wait time reported by the jbd2_run_stats | |
123 | * tracepoint will always be zero. | |
124 | */ | |
28e35e42 TM |
125 | static inline void update_t_max_wait(transaction_t *transaction, |
126 | unsigned long ts) | |
6d0bf005 TT |
127 | { |
128 | #ifdef CONFIG_JBD2_DEBUG | |
6d0bf005 TT |
129 | if (jbd2_journal_enable_debug && |
130 | time_after(transaction->t_start, ts)) { | |
131 | ts = jbd2_time_diff(ts, transaction->t_start); | |
132 | spin_lock(&transaction->t_handle_lock); | |
133 | if (ts > transaction->t_max_wait) | |
134 | transaction->t_max_wait = ts; | |
135 | spin_unlock(&transaction->t_handle_lock); | |
136 | } | |
137 | #endif | |
138 | } | |
139 | ||
470decc6 DK |
140 | /* |
141 | * start_this_handle: Given a handle, deal with any locking or stalling | |
142 | * needed to make sure that there is enough journal space for the handle | |
143 | * to begin. Attach the handle to a transaction and set up the | |
144 | * transaction's buffer credits. | |
145 | */ | |
146 | ||
47def826 | 147 | static int start_this_handle(journal_t *journal, handle_t *handle, |
d2159fb7 | 148 | gfp_t gfp_mask) |
470decc6 | 149 | { |
e4471831 TT |
150 | transaction_t *transaction, *new_transaction = NULL; |
151 | tid_t tid; | |
152 | int needed, need_to_start; | |
153 | int nblocks = handle->h_buffer_credits; | |
28e35e42 | 154 | unsigned long ts = jiffies; |
470decc6 DK |
155 | |
156 | if (nblocks > journal->j_max_transaction_buffers) { | |
f2a44523 | 157 | printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n", |
470decc6 DK |
158 | current->comm, nblocks, |
159 | journal->j_max_transaction_buffers); | |
47def826 | 160 | return -ENOSPC; |
470decc6 DK |
161 | } |
162 | ||
163 | alloc_transaction: | |
164 | if (!journal->j_running_transaction) { | |
b2f4edb3 WG |
165 | new_transaction = kmem_cache_zalloc(transaction_cache, |
166 | gfp_mask); | |
470decc6 | 167 | if (!new_transaction) { |
47def826 TT |
168 | /* |
169 | * If __GFP_FS is not present, then we may be | |
170 | * being called from inside the fs writeback | |
171 | * layer, so we MUST NOT fail. Since | |
172 | * __GFP_NOFAIL is going away, we will arrange | |
173 | * to retry the allocation ourselves. | |
174 | */ | |
175 | if ((gfp_mask & __GFP_FS) == 0) { | |
176 | congestion_wait(BLK_RW_ASYNC, HZ/50); | |
177 | goto alloc_transaction; | |
178 | } | |
179 | return -ENOMEM; | |
470decc6 | 180 | } |
470decc6 DK |
181 | } |
182 | ||
183 | jbd_debug(3, "New handle %p going live.\n", handle); | |
184 | ||
470decc6 DK |
185 | /* |
186 | * We need to hold j_state_lock until t_updates has been incremented, | |
187 | * for proper journal barrier handling | |
188 | */ | |
a931da6a TT |
189 | repeat: |
190 | read_lock(&journal->j_state_lock); | |
5c2178e7 | 191 | BUG_ON(journal->j_flags & JBD2_UNMOUNT); |
470decc6 | 192 | if (is_journal_aborted(journal) || |
f7f4bccb | 193 | (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
a931da6a | 194 | read_unlock(&journal->j_state_lock); |
0c2022ec | 195 | jbd2_journal_free_transaction(new_transaction); |
47def826 | 196 | return -EROFS; |
470decc6 DK |
197 | } |
198 | ||
199 | /* Wait on the journal's transaction barrier if necessary */ | |
200 | if (journal->j_barrier_count) { | |
a931da6a | 201 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
202 | wait_event(journal->j_wait_transaction_locked, |
203 | journal->j_barrier_count == 0); | |
204 | goto repeat; | |
205 | } | |
206 | ||
207 | if (!journal->j_running_transaction) { | |
a931da6a TT |
208 | read_unlock(&journal->j_state_lock); |
209 | if (!new_transaction) | |
470decc6 | 210 | goto alloc_transaction; |
a931da6a TT |
211 | write_lock(&journal->j_state_lock); |
212 | if (!journal->j_running_transaction) { | |
213 | jbd2_get_transaction(journal, new_transaction); | |
214 | new_transaction = NULL; | |
470decc6 | 215 | } |
a931da6a TT |
216 | write_unlock(&journal->j_state_lock); |
217 | goto repeat; | |
470decc6 DK |
218 | } |
219 | ||
220 | transaction = journal->j_running_transaction; | |
221 | ||
222 | /* | |
223 | * If the current transaction is locked down for commit, wait for the | |
224 | * lock to be released. | |
225 | */ | |
226 | if (transaction->t_state == T_LOCKED) { | |
227 | DEFINE_WAIT(wait); | |
228 | ||
229 | prepare_to_wait(&journal->j_wait_transaction_locked, | |
230 | &wait, TASK_UNINTERRUPTIBLE); | |
a931da6a | 231 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
232 | schedule(); |
233 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
234 | goto repeat; | |
235 | } | |
236 | ||
237 | /* | |
238 | * If there is not enough space left in the log to write all potential | |
239 | * buffers requested by this operation, we need to stall pending a log | |
240 | * checkpoint to free some more log space. | |
241 | */ | |
8dd42046 TT |
242 | needed = atomic_add_return(nblocks, |
243 | &transaction->t_outstanding_credits); | |
470decc6 DK |
244 | |
245 | if (needed > journal->j_max_transaction_buffers) { | |
246 | /* | |
247 | * If the current transaction is already too large, then start | |
248 | * to commit it: we can then go back and attach this handle to | |
249 | * a new transaction. | |
250 | */ | |
251 | DEFINE_WAIT(wait); | |
252 | ||
253 | jbd_debug(2, "Handle %p starting new commit...\n", handle); | |
8dd42046 | 254 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
255 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, |
256 | TASK_UNINTERRUPTIBLE); | |
e4471831 TT |
257 | tid = transaction->t_tid; |
258 | need_to_start = !tid_geq(journal->j_commit_request, tid); | |
a931da6a | 259 | read_unlock(&journal->j_state_lock); |
e4471831 TT |
260 | if (need_to_start) |
261 | jbd2_log_start_commit(journal, tid); | |
470decc6 DK |
262 | schedule(); |
263 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
264 | goto repeat; | |
265 | } | |
266 | ||
267 | /* | |
268 | * The commit code assumes that it can get enough log space | |
269 | * without forcing a checkpoint. This is *critical* for | |
270 | * correctness: a checkpoint of a buffer which is also | |
271 | * associated with a committing transaction creates a deadlock, | |
272 | * so commit simply cannot force through checkpoints. | |
273 | * | |
274 | * We must therefore ensure the necessary space in the journal | |
275 | * *before* starting to dirty potentially checkpointed buffers | |
276 | * in the new transaction. | |
277 | * | |
278 | * The worst part is, any transaction currently committing can | |
279 | * reduce the free space arbitrarily. Be careful to account for | |
280 | * those buffers when checkpointing. | |
281 | */ | |
282 | ||
283 | /* | |
284 | * @@@ AKPM: This seems rather over-defensive. We're giving commit | |
285 | * a _lot_ of headroom: 1/4 of the journal plus the size of | |
286 | * the committing transaction. Really, we only need to give it | |
287 | * committing_transaction->t_outstanding_credits plus "enough" for | |
288 | * the log control blocks. | |
a34f0b31 | 289 | * Also, this test is inconsistent with the matching one in |
f7f4bccb | 290 | * jbd2_journal_extend(). |
470decc6 | 291 | */ |
f7f4bccb | 292 | if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) { |
470decc6 | 293 | jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle); |
8dd42046 | 294 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
a931da6a TT |
295 | read_unlock(&journal->j_state_lock); |
296 | write_lock(&journal->j_state_lock); | |
297 | if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) | |
298 | __jbd2_log_wait_for_space(journal); | |
299 | write_unlock(&journal->j_state_lock); | |
300 | goto repeat; | |
470decc6 DK |
301 | } |
302 | ||
303 | /* OK, account for the buffers that this operation expects to | |
8dd42046 | 304 | * use and add the handle to the running transaction. |
8dd42046 | 305 | */ |
28e35e42 | 306 | update_t_max_wait(transaction, ts); |
470decc6 | 307 | handle->h_transaction = transaction; |
a51dca9c | 308 | atomic_inc(&transaction->t_updates); |
8dd42046 | 309 | atomic_inc(&transaction->t_handle_count); |
470decc6 | 310 | jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n", |
a51dca9c TT |
311 | handle, nblocks, |
312 | atomic_read(&transaction->t_outstanding_credits), | |
f7f4bccb | 313 | __jbd2_log_space_left(journal)); |
a931da6a | 314 | read_unlock(&journal->j_state_lock); |
9599b0e5 JK |
315 | |
316 | lock_map_acquire(&handle->h_lockdep_map); | |
0c2022ec | 317 | jbd2_journal_free_transaction(new_transaction); |
47def826 | 318 | return 0; |
470decc6 DK |
319 | } |
320 | ||
7b751066 MC |
321 | static struct lock_class_key jbd2_handle_key; |
322 | ||
470decc6 DK |
323 | /* Allocate a new handle. This should probably be in a slab... */ |
324 | static handle_t *new_handle(int nblocks) | |
325 | { | |
af1e76d6 | 326 | handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
470decc6 DK |
327 | if (!handle) |
328 | return NULL; | |
329 | memset(handle, 0, sizeof(*handle)); | |
330 | handle->h_buffer_credits = nblocks; | |
331 | handle->h_ref = 1; | |
332 | ||
7b751066 MC |
333 | lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle", |
334 | &jbd2_handle_key, 0); | |
335 | ||
470decc6 DK |
336 | return handle; |
337 | } | |
338 | ||
339 | /** | |
f7f4bccb | 340 | * handle_t *jbd2_journal_start() - Obtain a new handle. |
470decc6 DK |
341 | * @journal: Journal to start transaction on. |
342 | * @nblocks: number of block buffer we might modify | |
343 | * | |
344 | * We make sure that the transaction can guarantee at least nblocks of | |
345 | * modified buffers in the log. We block until the log can guarantee | |
346 | * that much space. | |
347 | * | |
348 | * This function is visible to journal users (like ext3fs), so is not | |
349 | * called with the journal already locked. | |
350 | * | |
c867516d EG |
351 | * Return a pointer to a newly allocated handle, or an ERR_PTR() value |
352 | * on failure. | |
470decc6 | 353 | */ |
d2159fb7 | 354 | handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask) |
470decc6 DK |
355 | { |
356 | handle_t *handle = journal_current_handle(); | |
357 | int err; | |
358 | ||
359 | if (!journal) | |
360 | return ERR_PTR(-EROFS); | |
361 | ||
362 | if (handle) { | |
363 | J_ASSERT(handle->h_transaction->t_journal == journal); | |
364 | handle->h_ref++; | |
365 | return handle; | |
366 | } | |
367 | ||
368 | handle = new_handle(nblocks); | |
369 | if (!handle) | |
370 | return ERR_PTR(-ENOMEM); | |
371 | ||
372 | current->journal_info = handle; | |
373 | ||
47def826 | 374 | err = start_this_handle(journal, handle, gfp_mask); |
470decc6 | 375 | if (err < 0) { |
af1e76d6 | 376 | jbd2_free_handle(handle); |
470decc6 DK |
377 | current->journal_info = NULL; |
378 | handle = ERR_PTR(err); | |
379 | } | |
380 | return handle; | |
381 | } | |
47def826 TT |
382 | EXPORT_SYMBOL(jbd2__journal_start); |
383 | ||
384 | ||
385 | handle_t *jbd2_journal_start(journal_t *journal, int nblocks) | |
386 | { | |
387 | return jbd2__journal_start(journal, nblocks, GFP_NOFS); | |
388 | } | |
389 | EXPORT_SYMBOL(jbd2_journal_start); | |
390 | ||
470decc6 DK |
391 | |
392 | /** | |
f7f4bccb | 393 | * int jbd2_journal_extend() - extend buffer credits. |
470decc6 DK |
394 | * @handle: handle to 'extend' |
395 | * @nblocks: nr blocks to try to extend by. | |
396 | * | |
397 | * Some transactions, such as large extends and truncates, can be done | |
398 | * atomically all at once or in several stages. The operation requests | |
399 | * a credit for a number of buffer modications in advance, but can | |
400 | * extend its credit if it needs more. | |
401 | * | |
f7f4bccb | 402 | * jbd2_journal_extend tries to give the running handle more buffer credits. |
470decc6 DK |
403 | * It does not guarantee that allocation - this is a best-effort only. |
404 | * The calling process MUST be able to deal cleanly with a failure to | |
405 | * extend here. | |
406 | * | |
407 | * Return 0 on success, non-zero on failure. | |
408 | * | |
409 | * return code < 0 implies an error | |
410 | * return code > 0 implies normal transaction-full status. | |
411 | */ | |
f7f4bccb | 412 | int jbd2_journal_extend(handle_t *handle, int nblocks) |
470decc6 DK |
413 | { |
414 | transaction_t *transaction = handle->h_transaction; | |
415 | journal_t *journal = transaction->t_journal; | |
416 | int result; | |
417 | int wanted; | |
418 | ||
419 | result = -EIO; | |
420 | if (is_handle_aborted(handle)) | |
421 | goto out; | |
422 | ||
423 | result = 1; | |
424 | ||
a931da6a | 425 | read_lock(&journal->j_state_lock); |
470decc6 DK |
426 | |
427 | /* Don't extend a locked-down transaction! */ | |
428 | if (handle->h_transaction->t_state != T_RUNNING) { | |
429 | jbd_debug(3, "denied handle %p %d blocks: " | |
430 | "transaction not running\n", handle, nblocks); | |
431 | goto error_out; | |
432 | } | |
433 | ||
434 | spin_lock(&transaction->t_handle_lock); | |
a51dca9c | 435 | wanted = atomic_read(&transaction->t_outstanding_credits) + nblocks; |
470decc6 DK |
436 | |
437 | if (wanted > journal->j_max_transaction_buffers) { | |
438 | jbd_debug(3, "denied handle %p %d blocks: " | |
439 | "transaction too large\n", handle, nblocks); | |
440 | goto unlock; | |
441 | } | |
442 | ||
f7f4bccb | 443 | if (wanted > __jbd2_log_space_left(journal)) { |
470decc6 DK |
444 | jbd_debug(3, "denied handle %p %d blocks: " |
445 | "insufficient log space\n", handle, nblocks); | |
446 | goto unlock; | |
447 | } | |
448 | ||
449 | handle->h_buffer_credits += nblocks; | |
a51dca9c | 450 | atomic_add(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
451 | result = 0; |
452 | ||
453 | jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); | |
454 | unlock: | |
455 | spin_unlock(&transaction->t_handle_lock); | |
456 | error_out: | |
a931da6a | 457 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
458 | out: |
459 | return result; | |
460 | } | |
461 | ||
462 | ||
463 | /** | |
f7f4bccb | 464 | * int jbd2_journal_restart() - restart a handle . |
470decc6 DK |
465 | * @handle: handle to restart |
466 | * @nblocks: nr credits requested | |
467 | * | |
468 | * Restart a handle for a multi-transaction filesystem | |
469 | * operation. | |
470 | * | |
f7f4bccb MC |
471 | * If the jbd2_journal_extend() call above fails to grant new buffer credits |
472 | * to a running handle, a call to jbd2_journal_restart will commit the | |
470decc6 DK |
473 | * handle's transaction so far and reattach the handle to a new |
474 | * transaction capabable of guaranteeing the requested number of | |
475 | * credits. | |
476 | */ | |
d2159fb7 | 477 | int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask) |
470decc6 DK |
478 | { |
479 | transaction_t *transaction = handle->h_transaction; | |
480 | journal_t *journal = transaction->t_journal; | |
e4471831 TT |
481 | tid_t tid; |
482 | int need_to_start, ret; | |
470decc6 DK |
483 | |
484 | /* If we've had an abort of any type, don't even think about | |
485 | * actually doing the restart! */ | |
486 | if (is_handle_aborted(handle)) | |
487 | return 0; | |
488 | ||
489 | /* | |
490 | * First unlink the handle from its current transaction, and start the | |
491 | * commit on that. | |
492 | */ | |
a51dca9c | 493 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 DK |
494 | J_ASSERT(journal_current_handle() == handle); |
495 | ||
a931da6a | 496 | read_lock(&journal->j_state_lock); |
470decc6 | 497 | spin_lock(&transaction->t_handle_lock); |
a51dca9c TT |
498 | atomic_sub(handle->h_buffer_credits, |
499 | &transaction->t_outstanding_credits); | |
500 | if (atomic_dec_and_test(&transaction->t_updates)) | |
470decc6 DK |
501 | wake_up(&journal->j_wait_updates); |
502 | spin_unlock(&transaction->t_handle_lock); | |
503 | ||
504 | jbd_debug(2, "restarting handle %p\n", handle); | |
e4471831 TT |
505 | tid = transaction->t_tid; |
506 | need_to_start = !tid_geq(journal->j_commit_request, tid); | |
a931da6a | 507 | read_unlock(&journal->j_state_lock); |
e4471831 TT |
508 | if (need_to_start) |
509 | jbd2_log_start_commit(journal, tid); | |
470decc6 | 510 | |
9599b0e5 | 511 | lock_map_release(&handle->h_lockdep_map); |
470decc6 | 512 | handle->h_buffer_credits = nblocks; |
47def826 | 513 | ret = start_this_handle(journal, handle, gfp_mask); |
470decc6 DK |
514 | return ret; |
515 | } | |
47def826 | 516 | EXPORT_SYMBOL(jbd2__journal_restart); |
470decc6 DK |
517 | |
518 | ||
47def826 TT |
519 | int jbd2_journal_restart(handle_t *handle, int nblocks) |
520 | { | |
521 | return jbd2__journal_restart(handle, nblocks, GFP_NOFS); | |
522 | } | |
523 | EXPORT_SYMBOL(jbd2_journal_restart); | |
524 | ||
470decc6 | 525 | /** |
f7f4bccb | 526 | * void jbd2_journal_lock_updates () - establish a transaction barrier. |
470decc6 DK |
527 | * @journal: Journal to establish a barrier on. |
528 | * | |
529 | * This locks out any further updates from being started, and blocks | |
530 | * until all existing updates have completed, returning only once the | |
531 | * journal is in a quiescent state with no updates running. | |
532 | * | |
533 | * The journal lock should not be held on entry. | |
534 | */ | |
f7f4bccb | 535 | void jbd2_journal_lock_updates(journal_t *journal) |
470decc6 DK |
536 | { |
537 | DEFINE_WAIT(wait); | |
538 | ||
a931da6a | 539 | write_lock(&journal->j_state_lock); |
470decc6 DK |
540 | ++journal->j_barrier_count; |
541 | ||
542 | /* Wait until there are no running updates */ | |
543 | while (1) { | |
544 | transaction_t *transaction = journal->j_running_transaction; | |
545 | ||
546 | if (!transaction) | |
547 | break; | |
548 | ||
549 | spin_lock(&transaction->t_handle_lock); | |
9837d8e9 JK |
550 | prepare_to_wait(&journal->j_wait_updates, &wait, |
551 | TASK_UNINTERRUPTIBLE); | |
a51dca9c | 552 | if (!atomic_read(&transaction->t_updates)) { |
470decc6 | 553 | spin_unlock(&transaction->t_handle_lock); |
9837d8e9 | 554 | finish_wait(&journal->j_wait_updates, &wait); |
470decc6 DK |
555 | break; |
556 | } | |
470decc6 | 557 | spin_unlock(&transaction->t_handle_lock); |
a931da6a | 558 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
559 | schedule(); |
560 | finish_wait(&journal->j_wait_updates, &wait); | |
a931da6a | 561 | write_lock(&journal->j_state_lock); |
470decc6 | 562 | } |
a931da6a | 563 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
564 | |
565 | /* | |
566 | * We have now established a barrier against other normal updates, but | |
f7f4bccb | 567 | * we also need to barrier against other jbd2_journal_lock_updates() calls |
470decc6 DK |
568 | * to make sure that we serialise special journal-locked operations |
569 | * too. | |
570 | */ | |
571 | mutex_lock(&journal->j_barrier); | |
572 | } | |
573 | ||
574 | /** | |
f7f4bccb | 575 | * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier |
470decc6 DK |
576 | * @journal: Journal to release the barrier on. |
577 | * | |
f7f4bccb | 578 | * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
470decc6 DK |
579 | * |
580 | * Should be called without the journal lock held. | |
581 | */ | |
f7f4bccb | 582 | void jbd2_journal_unlock_updates (journal_t *journal) |
470decc6 DK |
583 | { |
584 | J_ASSERT(journal->j_barrier_count != 0); | |
585 | ||
586 | mutex_unlock(&journal->j_barrier); | |
a931da6a | 587 | write_lock(&journal->j_state_lock); |
470decc6 | 588 | --journal->j_barrier_count; |
a931da6a | 589 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
590 | wake_up(&journal->j_wait_transaction_locked); |
591 | } | |
592 | ||
f91d1d04 | 593 | static void warn_dirty_buffer(struct buffer_head *bh) |
470decc6 | 594 | { |
f91d1d04 | 595 | char b[BDEVNAME_SIZE]; |
470decc6 | 596 | |
f91d1d04 | 597 | printk(KERN_WARNING |
f2a44523 | 598 | "JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). " |
f91d1d04 JK |
599 | "There's a risk of filesystem corruption in case of system " |
600 | "crash.\n", | |
601 | bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr); | |
470decc6 DK |
602 | } |
603 | ||
604 | /* | |
605 | * If the buffer is already part of the current transaction, then there | |
606 | * is nothing we need to do. If it is already part of a prior | |
607 | * transaction which we are still committing to disk, then we need to | |
608 | * make sure that we do not overwrite the old copy: we do copy-out to | |
609 | * preserve the copy going to disk. We also account the buffer against | |
610 | * the handle's metadata buffer credits (unless the buffer is already | |
611 | * part of the transaction, that is). | |
612 | * | |
613 | */ | |
614 | static int | |
615 | do_get_write_access(handle_t *handle, struct journal_head *jh, | |
616 | int force_copy) | |
617 | { | |
618 | struct buffer_head *bh; | |
619 | transaction_t *transaction; | |
620 | journal_t *journal; | |
621 | int error; | |
622 | char *frozen_buffer = NULL; | |
623 | int need_copy = 0; | |
624 | ||
625 | if (is_handle_aborted(handle)) | |
626 | return -EROFS; | |
627 | ||
628 | transaction = handle->h_transaction; | |
629 | journal = transaction->t_journal; | |
630 | ||
cfef2c6a | 631 | jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy); |
470decc6 DK |
632 | |
633 | JBUFFER_TRACE(jh, "entry"); | |
634 | repeat: | |
635 | bh = jh2bh(jh); | |
636 | ||
637 | /* @@@ Need to check for errors here at some point. */ | |
638 | ||
639 | lock_buffer(bh); | |
640 | jbd_lock_bh_state(bh); | |
641 | ||
642 | /* We now hold the buffer lock so it is safe to query the buffer | |
643 | * state. Is the buffer dirty? | |
644 | * | |
645 | * If so, there are two possibilities. The buffer may be | |
646 | * non-journaled, and undergoing a quite legitimate writeback. | |
647 | * Otherwise, it is journaled, and we don't expect dirty buffers | |
648 | * in that state (the buffers should be marked JBD_Dirty | |
649 | * instead.) So either the IO is being done under our own | |
650 | * control and this is a bug, or it's a third party IO such as | |
651 | * dump(8) (which may leave the buffer scheduled for read --- | |
652 | * ie. locked but not dirty) or tune2fs (which may actually have | |
653 | * the buffer dirtied, ugh.) */ | |
654 | ||
655 | if (buffer_dirty(bh)) { | |
656 | /* | |
657 | * First question: is this buffer already part of the current | |
658 | * transaction or the existing committing transaction? | |
659 | */ | |
660 | if (jh->b_transaction) { | |
661 | J_ASSERT_JH(jh, | |
662 | jh->b_transaction == transaction || | |
663 | jh->b_transaction == | |
664 | journal->j_committing_transaction); | |
665 | if (jh->b_next_transaction) | |
666 | J_ASSERT_JH(jh, jh->b_next_transaction == | |
667 | transaction); | |
f91d1d04 | 668 | warn_dirty_buffer(bh); |
470decc6 DK |
669 | } |
670 | /* | |
671 | * In any case we need to clean the dirty flag and we must | |
672 | * do it under the buffer lock to be sure we don't race | |
673 | * with running write-out. | |
674 | */ | |
f91d1d04 JK |
675 | JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
676 | clear_buffer_dirty(bh); | |
677 | set_buffer_jbddirty(bh); | |
470decc6 DK |
678 | } |
679 | ||
680 | unlock_buffer(bh); | |
681 | ||
682 | error = -EROFS; | |
683 | if (is_handle_aborted(handle)) { | |
684 | jbd_unlock_bh_state(bh); | |
685 | goto out; | |
686 | } | |
687 | error = 0; | |
688 | ||
689 | /* | |
690 | * The buffer is already part of this transaction if b_transaction or | |
691 | * b_next_transaction points to it | |
692 | */ | |
693 | if (jh->b_transaction == transaction || | |
694 | jh->b_next_transaction == transaction) | |
695 | goto done; | |
696 | ||
9fc7c63a JB |
697 | /* |
698 | * this is the first time this transaction is touching this buffer, | |
699 | * reset the modified flag | |
700 | */ | |
701 | jh->b_modified = 0; | |
702 | ||
470decc6 DK |
703 | /* |
704 | * If there is already a copy-out version of this buffer, then we don't | |
705 | * need to make another one | |
706 | */ | |
707 | if (jh->b_frozen_data) { | |
708 | JBUFFER_TRACE(jh, "has frozen data"); | |
709 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
710 | jh->b_next_transaction = transaction; | |
711 | goto done; | |
712 | } | |
713 | ||
714 | /* Is there data here we need to preserve? */ | |
715 | ||
716 | if (jh->b_transaction && jh->b_transaction != transaction) { | |
717 | JBUFFER_TRACE(jh, "owned by older transaction"); | |
718 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
719 | J_ASSERT_JH(jh, jh->b_transaction == | |
720 | journal->j_committing_transaction); | |
721 | ||
722 | /* There is one case we have to be very careful about. | |
723 | * If the committing transaction is currently writing | |
724 | * this buffer out to disk and has NOT made a copy-out, | |
725 | * then we cannot modify the buffer contents at all | |
726 | * right now. The essence of copy-out is that it is the | |
727 | * extra copy, not the primary copy, which gets | |
728 | * journaled. If the primary copy is already going to | |
729 | * disk then we cannot do copy-out here. */ | |
730 | ||
731 | if (jh->b_jlist == BJ_Shadow) { | |
732 | DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow); | |
733 | wait_queue_head_t *wqh; | |
734 | ||
735 | wqh = bit_waitqueue(&bh->b_state, BH_Unshadow); | |
736 | ||
737 | JBUFFER_TRACE(jh, "on shadow: sleep"); | |
738 | jbd_unlock_bh_state(bh); | |
739 | /* commit wakes up all shadow buffers after IO */ | |
740 | for ( ; ; ) { | |
741 | prepare_to_wait(wqh, &wait.wait, | |
742 | TASK_UNINTERRUPTIBLE); | |
743 | if (jh->b_jlist != BJ_Shadow) | |
744 | break; | |
745 | schedule(); | |
746 | } | |
747 | finish_wait(wqh, &wait.wait); | |
748 | goto repeat; | |
749 | } | |
750 | ||
751 | /* Only do the copy if the currently-owning transaction | |
752 | * still needs it. If it is on the Forget list, the | |
753 | * committing transaction is past that stage. The | |
754 | * buffer had better remain locked during the kmalloc, | |
755 | * but that should be true --- we hold the journal lock | |
756 | * still and the buffer is already on the BUF_JOURNAL | |
757 | * list so won't be flushed. | |
758 | * | |
759 | * Subtle point, though: if this is a get_undo_access, | |
760 | * then we will be relying on the frozen_data to contain | |
761 | * the new value of the committed_data record after the | |
762 | * transaction, so we HAVE to force the frozen_data copy | |
763 | * in that case. */ | |
764 | ||
765 | if (jh->b_jlist != BJ_Forget || force_copy) { | |
766 | JBUFFER_TRACE(jh, "generate frozen data"); | |
767 | if (!frozen_buffer) { | |
768 | JBUFFER_TRACE(jh, "allocate memory for buffer"); | |
769 | jbd_unlock_bh_state(bh); | |
770 | frozen_buffer = | |
af1e76d6 | 771 | jbd2_alloc(jh2bh(jh)->b_size, |
470decc6 DK |
772 | GFP_NOFS); |
773 | if (!frozen_buffer) { | |
774 | printk(KERN_EMERG | |
775 | "%s: OOM for frozen_buffer\n", | |
329d291f | 776 | __func__); |
470decc6 DK |
777 | JBUFFER_TRACE(jh, "oom!"); |
778 | error = -ENOMEM; | |
779 | jbd_lock_bh_state(bh); | |
780 | goto done; | |
781 | } | |
782 | goto repeat; | |
783 | } | |
784 | jh->b_frozen_data = frozen_buffer; | |
785 | frozen_buffer = NULL; | |
786 | need_copy = 1; | |
787 | } | |
788 | jh->b_next_transaction = transaction; | |
789 | } | |
790 | ||
791 | ||
792 | /* | |
793 | * Finally, if the buffer is not journaled right now, we need to make | |
794 | * sure it doesn't get written to disk before the caller actually | |
795 | * commits the new data | |
796 | */ | |
797 | if (!jh->b_transaction) { | |
798 | JBUFFER_TRACE(jh, "no transaction"); | |
799 | J_ASSERT_JH(jh, !jh->b_next_transaction); | |
470decc6 DK |
800 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
801 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 802 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 DK |
803 | spin_unlock(&journal->j_list_lock); |
804 | } | |
805 | ||
806 | done: | |
807 | if (need_copy) { | |
808 | struct page *page; | |
809 | int offset; | |
810 | char *source; | |
811 | ||
812 | J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)), | |
813 | "Possible IO failure.\n"); | |
814 | page = jh2bh(jh)->b_page; | |
a1dd5331 | 815 | offset = offset_in_page(jh2bh(jh)->b_data); |
303a8f2a | 816 | source = kmap_atomic(page); |
13ceef09 JK |
817 | /* Fire data frozen trigger just before we copy the data */ |
818 | jbd2_buffer_frozen_trigger(jh, source + offset, | |
819 | jh->b_triggers); | |
470decc6 | 820 | memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size); |
303a8f2a | 821 | kunmap_atomic(source); |
e06c8227 JB |
822 | |
823 | /* | |
824 | * Now that the frozen data is saved off, we need to store | |
825 | * any matching triggers. | |
826 | */ | |
827 | jh->b_frozen_triggers = jh->b_triggers; | |
470decc6 DK |
828 | } |
829 | jbd_unlock_bh_state(bh); | |
830 | ||
831 | /* | |
832 | * If we are about to journal a buffer, then any revoke pending on it is | |
833 | * no longer valid | |
834 | */ | |
f7f4bccb | 835 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 DK |
836 | |
837 | out: | |
838 | if (unlikely(frozen_buffer)) /* It's usually NULL */ | |
af1e76d6 | 839 | jbd2_free(frozen_buffer, bh->b_size); |
470decc6 DK |
840 | |
841 | JBUFFER_TRACE(jh, "exit"); | |
842 | return error; | |
843 | } | |
844 | ||
845 | /** | |
f7f4bccb | 846 | * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update. |
470decc6 DK |
847 | * @handle: transaction to add buffer modifications to |
848 | * @bh: bh to be used for metadata writes | |
470decc6 DK |
849 | * |
850 | * Returns an error code or 0 on success. | |
851 | * | |
852 | * In full data journalling mode the buffer may be of type BJ_AsyncData, | |
853 | * because we're write()ing a buffer which is also part of a shared mapping. | |
854 | */ | |
855 | ||
f7f4bccb | 856 | int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
470decc6 | 857 | { |
f7f4bccb | 858 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
859 | int rc; |
860 | ||
861 | /* We do not want to get caught playing with fields which the | |
862 | * log thread also manipulates. Make sure that the buffer | |
863 | * completes any outstanding IO before proceeding. */ | |
864 | rc = do_get_write_access(handle, jh, 0); | |
f7f4bccb | 865 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
866 | return rc; |
867 | } | |
868 | ||
869 | ||
870 | /* | |
871 | * When the user wants to journal a newly created buffer_head | |
872 | * (ie. getblk() returned a new buffer and we are going to populate it | |
873 | * manually rather than reading off disk), then we need to keep the | |
874 | * buffer_head locked until it has been completely filled with new | |
875 | * data. In this case, we should be able to make the assertion that | |
876 | * the bh is not already part of an existing transaction. | |
877 | * | |
878 | * The buffer should already be locked by the caller by this point. | |
879 | * There is no lock ranking violation: it was a newly created, | |
880 | * unlocked buffer beforehand. */ | |
881 | ||
882 | /** | |
f7f4bccb | 883 | * int jbd2_journal_get_create_access () - notify intent to use newly created bh |
470decc6 DK |
884 | * @handle: transaction to new buffer to |
885 | * @bh: new buffer. | |
886 | * | |
887 | * Call this if you create a new bh. | |
888 | */ | |
f7f4bccb | 889 | int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
890 | { |
891 | transaction_t *transaction = handle->h_transaction; | |
892 | journal_t *journal = transaction->t_journal; | |
f7f4bccb | 893 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
894 | int err; |
895 | ||
896 | jbd_debug(5, "journal_head %p\n", jh); | |
897 | err = -EROFS; | |
898 | if (is_handle_aborted(handle)) | |
899 | goto out; | |
900 | err = 0; | |
901 | ||
902 | JBUFFER_TRACE(jh, "entry"); | |
903 | /* | |
904 | * The buffer may already belong to this transaction due to pre-zeroing | |
905 | * in the filesystem's new_block code. It may also be on the previous, | |
906 | * committing transaction's lists, but it HAS to be in Forget state in | |
907 | * that case: the transaction must have deleted the buffer for it to be | |
908 | * reused here. | |
909 | */ | |
910 | jbd_lock_bh_state(bh); | |
911 | spin_lock(&journal->j_list_lock); | |
912 | J_ASSERT_JH(jh, (jh->b_transaction == transaction || | |
913 | jh->b_transaction == NULL || | |
914 | (jh->b_transaction == journal->j_committing_transaction && | |
915 | jh->b_jlist == BJ_Forget))); | |
916 | ||
917 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
918 | J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); | |
919 | ||
920 | if (jh->b_transaction == NULL) { | |
f91d1d04 JK |
921 | /* |
922 | * Previous jbd2_journal_forget() could have left the buffer | |
923 | * with jbddirty bit set because it was being committed. When | |
924 | * the commit finished, we've filed the buffer for | |
925 | * checkpointing and marked it dirty. Now we are reallocating | |
926 | * the buffer so the transaction freeing it must have | |
927 | * committed and so it's safe to clear the dirty bit. | |
928 | */ | |
929 | clear_buffer_dirty(jh2bh(jh)); | |
9fc7c63a JB |
930 | /* first access by this transaction */ |
931 | jh->b_modified = 0; | |
932 | ||
470decc6 | 933 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
f7f4bccb | 934 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 | 935 | } else if (jh->b_transaction == journal->j_committing_transaction) { |
9fc7c63a JB |
936 | /* first access by this transaction */ |
937 | jh->b_modified = 0; | |
938 | ||
470decc6 DK |
939 | JBUFFER_TRACE(jh, "set next transaction"); |
940 | jh->b_next_transaction = transaction; | |
941 | } | |
942 | spin_unlock(&journal->j_list_lock); | |
943 | jbd_unlock_bh_state(bh); | |
944 | ||
945 | /* | |
946 | * akpm: I added this. ext3_alloc_branch can pick up new indirect | |
947 | * blocks which contain freed but then revoked metadata. We need | |
948 | * to cancel the revoke in case we end up freeing it yet again | |
949 | * and the reallocating as data - this would cause a second revoke, | |
950 | * which hits an assertion error. | |
951 | */ | |
952 | JBUFFER_TRACE(jh, "cancelling revoke"); | |
f7f4bccb | 953 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 | 954 | out: |
3991b400 | 955 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
956 | return err; |
957 | } | |
958 | ||
959 | /** | |
f7f4bccb | 960 | * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
470decc6 DK |
961 | * non-rewindable consequences |
962 | * @handle: transaction | |
963 | * @bh: buffer to undo | |
470decc6 DK |
964 | * |
965 | * Sometimes there is a need to distinguish between metadata which has | |
966 | * been committed to disk and that which has not. The ext3fs code uses | |
967 | * this for freeing and allocating space, we have to make sure that we | |
968 | * do not reuse freed space until the deallocation has been committed, | |
969 | * since if we overwrote that space we would make the delete | |
970 | * un-rewindable in case of a crash. | |
971 | * | |
f7f4bccb | 972 | * To deal with that, jbd2_journal_get_undo_access requests write access to a |
470decc6 DK |
973 | * buffer for parts of non-rewindable operations such as delete |
974 | * operations on the bitmaps. The journaling code must keep a copy of | |
975 | * the buffer's contents prior to the undo_access call until such time | |
976 | * as we know that the buffer has definitely been committed to disk. | |
977 | * | |
978 | * We never need to know which transaction the committed data is part | |
979 | * of, buffers touched here are guaranteed to be dirtied later and so | |
980 | * will be committed to a new transaction in due course, at which point | |
981 | * we can discard the old committed data pointer. | |
982 | * | |
983 | * Returns error number or 0 on success. | |
984 | */ | |
f7f4bccb | 985 | int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
986 | { |
987 | int err; | |
f7f4bccb | 988 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
989 | char *committed_data = NULL; |
990 | ||
991 | JBUFFER_TRACE(jh, "entry"); | |
992 | ||
993 | /* | |
994 | * Do this first --- it can drop the journal lock, so we want to | |
995 | * make sure that obtaining the committed_data is done | |
996 | * atomically wrt. completion of any outstanding commits. | |
997 | */ | |
998 | err = do_get_write_access(handle, jh, 1); | |
999 | if (err) | |
1000 | goto out; | |
1001 | ||
1002 | repeat: | |
1003 | if (!jh->b_committed_data) { | |
af1e76d6 | 1004 | committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); |
470decc6 DK |
1005 | if (!committed_data) { |
1006 | printk(KERN_EMERG "%s: No memory for committed data\n", | |
329d291f | 1007 | __func__); |
470decc6 DK |
1008 | err = -ENOMEM; |
1009 | goto out; | |
1010 | } | |
1011 | } | |
1012 | ||
1013 | jbd_lock_bh_state(bh); | |
1014 | if (!jh->b_committed_data) { | |
1015 | /* Copy out the current buffer contents into the | |
1016 | * preserved, committed copy. */ | |
1017 | JBUFFER_TRACE(jh, "generate b_committed data"); | |
1018 | if (!committed_data) { | |
1019 | jbd_unlock_bh_state(bh); | |
1020 | goto repeat; | |
1021 | } | |
1022 | ||
1023 | jh->b_committed_data = committed_data; | |
1024 | committed_data = NULL; | |
1025 | memcpy(jh->b_committed_data, bh->b_data, bh->b_size); | |
1026 | } | |
1027 | jbd_unlock_bh_state(bh); | |
1028 | out: | |
f7f4bccb | 1029 | jbd2_journal_put_journal_head(jh); |
470decc6 | 1030 | if (unlikely(committed_data)) |
af1e76d6 | 1031 | jbd2_free(committed_data, bh->b_size); |
470decc6 DK |
1032 | return err; |
1033 | } | |
1034 | ||
e06c8227 JB |
1035 | /** |
1036 | * void jbd2_journal_set_triggers() - Add triggers for commit writeout | |
1037 | * @bh: buffer to trigger on | |
1038 | * @type: struct jbd2_buffer_trigger_type containing the trigger(s). | |
1039 | * | |
1040 | * Set any triggers on this journal_head. This is always safe, because | |
1041 | * triggers for a committing buffer will be saved off, and triggers for | |
1042 | * a running transaction will match the buffer in that transaction. | |
1043 | * | |
1044 | * Call with NULL to clear the triggers. | |
1045 | */ | |
1046 | void jbd2_journal_set_triggers(struct buffer_head *bh, | |
1047 | struct jbd2_buffer_trigger_type *type) | |
1048 | { | |
1049 | struct journal_head *jh = bh2jh(bh); | |
1050 | ||
1051 | jh->b_triggers = type; | |
1052 | } | |
1053 | ||
13ceef09 | 1054 | void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data, |
e06c8227 JB |
1055 | struct jbd2_buffer_trigger_type *triggers) |
1056 | { | |
1057 | struct buffer_head *bh = jh2bh(jh); | |
1058 | ||
13ceef09 | 1059 | if (!triggers || !triggers->t_frozen) |
e06c8227 JB |
1060 | return; |
1061 | ||
13ceef09 | 1062 | triggers->t_frozen(triggers, bh, mapped_data, bh->b_size); |
e06c8227 JB |
1063 | } |
1064 | ||
1065 | void jbd2_buffer_abort_trigger(struct journal_head *jh, | |
1066 | struct jbd2_buffer_trigger_type *triggers) | |
1067 | { | |
1068 | if (!triggers || !triggers->t_abort) | |
1069 | return; | |
1070 | ||
1071 | triggers->t_abort(triggers, jh2bh(jh)); | |
1072 | } | |
1073 | ||
1074 | ||
1075 | ||
470decc6 | 1076 | /** |
f7f4bccb | 1077 | * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
470decc6 DK |
1078 | * @handle: transaction to add buffer to. |
1079 | * @bh: buffer to mark | |
1080 | * | |
1081 | * mark dirty metadata which needs to be journaled as part of the current | |
1082 | * transaction. | |
1083 | * | |
9ea7a0df TT |
1084 | * The buffer must have previously had jbd2_journal_get_write_access() |
1085 | * called so that it has a valid journal_head attached to the buffer | |
1086 | * head. | |
1087 | * | |
470decc6 DK |
1088 | * The buffer is placed on the transaction's metadata list and is marked |
1089 | * as belonging to the transaction. | |
1090 | * | |
1091 | * Returns error number or 0 on success. | |
1092 | * | |
1093 | * Special care needs to be taken if the buffer already belongs to the | |
1094 | * current committing transaction (in which case we should have frozen | |
1095 | * data present for that commit). In that case, we don't relink the | |
1096 | * buffer: that only gets done when the old transaction finally | |
1097 | * completes its commit. | |
1098 | */ | |
f7f4bccb | 1099 | int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1100 | { |
1101 | transaction_t *transaction = handle->h_transaction; | |
1102 | journal_t *journal = transaction->t_journal; | |
1103 | struct journal_head *jh = bh2jh(bh); | |
9ea7a0df | 1104 | int ret = 0; |
470decc6 DK |
1105 | |
1106 | jbd_debug(5, "journal_head %p\n", jh); | |
1107 | JBUFFER_TRACE(jh, "entry"); | |
1108 | if (is_handle_aborted(handle)) | |
1109 | goto out; | |
9ea7a0df TT |
1110 | if (!buffer_jbd(bh)) { |
1111 | ret = -EUCLEAN; | |
1112 | goto out; | |
1113 | } | |
470decc6 DK |
1114 | |
1115 | jbd_lock_bh_state(bh); | |
1116 | ||
1117 | if (jh->b_modified == 0) { | |
1118 | /* | |
1119 | * This buffer's got modified and becoming part | |
1120 | * of the transaction. This needs to be done | |
1121 | * once a transaction -bzzz | |
1122 | */ | |
1123 | jh->b_modified = 1; | |
1124 | J_ASSERT_JH(jh, handle->h_buffer_credits > 0); | |
1125 | handle->h_buffer_credits--; | |
1126 | } | |
1127 | ||
1128 | /* | |
1129 | * fastpath, to avoid expensive locking. If this buffer is already | |
1130 | * on the running transaction's metadata list there is nothing to do. | |
1131 | * Nobody can take it off again because there is a handle open. | |
1132 | * I _think_ we're OK here with SMP barriers - a mistaken decision will | |
1133 | * result in this test being false, so we go in and take the locks. | |
1134 | */ | |
1135 | if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { | |
1136 | JBUFFER_TRACE(jh, "fastpath"); | |
9ea7a0df TT |
1137 | if (unlikely(jh->b_transaction != |
1138 | journal->j_running_transaction)) { | |
1139 | printk(KERN_EMERG "JBD: %s: " | |
1140 | "jh->b_transaction (%llu, %p, %u) != " | |
1141 | "journal->j_running_transaction (%p, %u)", | |
1142 | journal->j_devname, | |
1143 | (unsigned long long) bh->b_blocknr, | |
1144 | jh->b_transaction, | |
1145 | jh->b_transaction ? jh->b_transaction->t_tid : 0, | |
1146 | journal->j_running_transaction, | |
1147 | journal->j_running_transaction ? | |
1148 | journal->j_running_transaction->t_tid : 0); | |
1149 | ret = -EINVAL; | |
1150 | } | |
470decc6 DK |
1151 | goto out_unlock_bh; |
1152 | } | |
1153 | ||
1154 | set_buffer_jbddirty(bh); | |
1155 | ||
1156 | /* | |
1157 | * Metadata already on the current transaction list doesn't | |
1158 | * need to be filed. Metadata on another transaction's list must | |
1159 | * be committing, and will be refiled once the commit completes: | |
1160 | * leave it alone for now. | |
1161 | */ | |
1162 | if (jh->b_transaction != transaction) { | |
1163 | JBUFFER_TRACE(jh, "already on other transaction"); | |
9ea7a0df TT |
1164 | if (unlikely(jh->b_transaction != |
1165 | journal->j_committing_transaction)) { | |
1166 | printk(KERN_EMERG "JBD: %s: " | |
1167 | "jh->b_transaction (%llu, %p, %u) != " | |
1168 | "journal->j_committing_transaction (%p, %u)", | |
1169 | journal->j_devname, | |
1170 | (unsigned long long) bh->b_blocknr, | |
1171 | jh->b_transaction, | |
1172 | jh->b_transaction ? jh->b_transaction->t_tid : 0, | |
1173 | journal->j_committing_transaction, | |
1174 | journal->j_committing_transaction ? | |
1175 | journal->j_committing_transaction->t_tid : 0); | |
1176 | ret = -EINVAL; | |
1177 | } | |
1178 | if (unlikely(jh->b_next_transaction != transaction)) { | |
1179 | printk(KERN_EMERG "JBD: %s: " | |
1180 | "jh->b_next_transaction (%llu, %p, %u) != " | |
1181 | "transaction (%p, %u)", | |
1182 | journal->j_devname, | |
1183 | (unsigned long long) bh->b_blocknr, | |
1184 | jh->b_next_transaction, | |
1185 | jh->b_next_transaction ? | |
1186 | jh->b_next_transaction->t_tid : 0, | |
1187 | transaction, transaction->t_tid); | |
1188 | ret = -EINVAL; | |
1189 | } | |
470decc6 DK |
1190 | /* And this case is illegal: we can't reuse another |
1191 | * transaction's data buffer, ever. */ | |
1192 | goto out_unlock_bh; | |
1193 | } | |
1194 | ||
1195 | /* That test should have eliminated the following case: */ | |
4019191b | 1196 | J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
470decc6 DK |
1197 | |
1198 | JBUFFER_TRACE(jh, "file as BJ_Metadata"); | |
1199 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 1200 | __jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata); |
470decc6 DK |
1201 | spin_unlock(&journal->j_list_lock); |
1202 | out_unlock_bh: | |
1203 | jbd_unlock_bh_state(bh); | |
1204 | out: | |
1205 | JBUFFER_TRACE(jh, "exit"); | |
44705754 | 1206 | WARN_ON(ret); /* All errors are bugs, so dump the stack */ |
9ea7a0df | 1207 | return ret; |
470decc6 DK |
1208 | } |
1209 | ||
470decc6 | 1210 | /** |
f7f4bccb | 1211 | * void jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
470decc6 DK |
1212 | * @handle: transaction handle |
1213 | * @bh: bh to 'forget' | |
1214 | * | |
1215 | * We can only do the bforget if there are no commits pending against the | |
1216 | * buffer. If the buffer is dirty in the current running transaction we | |
1217 | * can safely unlink it. | |
1218 | * | |
1219 | * bh may not be a journalled buffer at all - it may be a non-JBD | |
1220 | * buffer which came off the hashtable. Check for this. | |
1221 | * | |
1222 | * Decrements bh->b_count by one. | |
1223 | * | |
1224 | * Allow this call even if the handle has aborted --- it may be part of | |
1225 | * the caller's cleanup after an abort. | |
1226 | */ | |
f7f4bccb | 1227 | int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1228 | { |
1229 | transaction_t *transaction = handle->h_transaction; | |
1230 | journal_t *journal = transaction->t_journal; | |
1231 | struct journal_head *jh; | |
1232 | int drop_reserve = 0; | |
1233 | int err = 0; | |
1dfc3220 | 1234 | int was_modified = 0; |
470decc6 DK |
1235 | |
1236 | BUFFER_TRACE(bh, "entry"); | |
1237 | ||
1238 | jbd_lock_bh_state(bh); | |
1239 | spin_lock(&journal->j_list_lock); | |
1240 | ||
1241 | if (!buffer_jbd(bh)) | |
1242 | goto not_jbd; | |
1243 | jh = bh2jh(bh); | |
1244 | ||
1245 | /* Critical error: attempting to delete a bitmap buffer, maybe? | |
1246 | * Don't do any jbd operations, and return an error. */ | |
1247 | if (!J_EXPECT_JH(jh, !jh->b_committed_data, | |
1248 | "inconsistent data on disk")) { | |
1249 | err = -EIO; | |
1250 | goto not_jbd; | |
1251 | } | |
1252 | ||
1dfc3220 JB |
1253 | /* keep track of wether or not this transaction modified us */ |
1254 | was_modified = jh->b_modified; | |
1255 | ||
470decc6 DK |
1256 | /* |
1257 | * The buffer's going from the transaction, we must drop | |
1258 | * all references -bzzz | |
1259 | */ | |
1260 | jh->b_modified = 0; | |
1261 | ||
1262 | if (jh->b_transaction == handle->h_transaction) { | |
1263 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
1264 | ||
1265 | /* If we are forgetting a buffer which is already part | |
1266 | * of this transaction, then we can just drop it from | |
1267 | * the transaction immediately. */ | |
1268 | clear_buffer_dirty(bh); | |
1269 | clear_buffer_jbddirty(bh); | |
1270 | ||
1271 | JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); | |
1272 | ||
1dfc3220 JB |
1273 | /* |
1274 | * we only want to drop a reference if this transaction | |
1275 | * modified the buffer | |
1276 | */ | |
1277 | if (was_modified) | |
1278 | drop_reserve = 1; | |
470decc6 DK |
1279 | |
1280 | /* | |
1281 | * We are no longer going to journal this buffer. | |
1282 | * However, the commit of this transaction is still | |
1283 | * important to the buffer: the delete that we are now | |
1284 | * processing might obsolete an old log entry, so by | |
1285 | * committing, we can satisfy the buffer's checkpoint. | |
1286 | * | |
1287 | * So, if we have a checkpoint on the buffer, we should | |
1288 | * now refile the buffer on our BJ_Forget list so that | |
1289 | * we know to remove the checkpoint after we commit. | |
1290 | */ | |
1291 | ||
1292 | if (jh->b_cp_transaction) { | |
f7f4bccb MC |
1293 | __jbd2_journal_temp_unlink_buffer(jh); |
1294 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
470decc6 | 1295 | } else { |
f7f4bccb | 1296 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1297 | if (!buffer_jbd(bh)) { |
1298 | spin_unlock(&journal->j_list_lock); | |
1299 | jbd_unlock_bh_state(bh); | |
1300 | __bforget(bh); | |
1301 | goto drop; | |
1302 | } | |
1303 | } | |
1304 | } else if (jh->b_transaction) { | |
1305 | J_ASSERT_JH(jh, (jh->b_transaction == | |
1306 | journal->j_committing_transaction)); | |
1307 | /* However, if the buffer is still owned by a prior | |
1308 | * (committing) transaction, we can't drop it yet... */ | |
1309 | JBUFFER_TRACE(jh, "belongs to older transaction"); | |
1310 | /* ... but we CAN drop it from the new transaction if we | |
1311 | * have also modified it since the original commit. */ | |
1312 | ||
1313 | if (jh->b_next_transaction) { | |
1314 | J_ASSERT(jh->b_next_transaction == transaction); | |
1315 | jh->b_next_transaction = NULL; | |
1dfc3220 JB |
1316 | |
1317 | /* | |
1318 | * only drop a reference if this transaction modified | |
1319 | * the buffer | |
1320 | */ | |
1321 | if (was_modified) | |
1322 | drop_reserve = 1; | |
470decc6 DK |
1323 | } |
1324 | } | |
1325 | ||
1326 | not_jbd: | |
1327 | spin_unlock(&journal->j_list_lock); | |
1328 | jbd_unlock_bh_state(bh); | |
1329 | __brelse(bh); | |
1330 | drop: | |
1331 | if (drop_reserve) { | |
1332 | /* no need to reserve log space for this block -bzzz */ | |
1333 | handle->h_buffer_credits++; | |
1334 | } | |
1335 | return err; | |
1336 | } | |
1337 | ||
1338 | /** | |
f7f4bccb | 1339 | * int jbd2_journal_stop() - complete a transaction |
470decc6 DK |
1340 | * @handle: tranaction to complete. |
1341 | * | |
1342 | * All done for a particular handle. | |
1343 | * | |
1344 | * There is not much action needed here. We just return any remaining | |
1345 | * buffer credits to the transaction and remove the handle. The only | |
1346 | * complication is that we need to start a commit operation if the | |
1347 | * filesystem is marked for synchronous update. | |
1348 | * | |
f7f4bccb | 1349 | * jbd2_journal_stop itself will not usually return an error, but it may |
470decc6 | 1350 | * do so in unusual circumstances. In particular, expect it to |
f7f4bccb | 1351 | * return -EIO if a jbd2_journal_abort has been executed since the |
470decc6 DK |
1352 | * transaction began. |
1353 | */ | |
f7f4bccb | 1354 | int jbd2_journal_stop(handle_t *handle) |
470decc6 DK |
1355 | { |
1356 | transaction_t *transaction = handle->h_transaction; | |
1357 | journal_t *journal = transaction->t_journal; | |
a51dca9c TT |
1358 | int err, wait_for_commit = 0; |
1359 | tid_t tid; | |
470decc6 DK |
1360 | pid_t pid; |
1361 | ||
470decc6 DK |
1362 | J_ASSERT(journal_current_handle() == handle); |
1363 | ||
1364 | if (is_handle_aborted(handle)) | |
1365 | err = -EIO; | |
3e2a532b | 1366 | else { |
a51dca9c | 1367 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 | 1368 | err = 0; |
3e2a532b | 1369 | } |
470decc6 DK |
1370 | |
1371 | if (--handle->h_ref > 0) { | |
1372 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1373 | handle->h_ref); | |
1374 | return err; | |
1375 | } | |
1376 | ||
1377 | jbd_debug(4, "Handle %p going down\n", handle); | |
1378 | ||
1379 | /* | |
1380 | * Implement synchronous transaction batching. If the handle | |
1381 | * was synchronous, don't force a commit immediately. Let's | |
e07f7183 JB |
1382 | * yield and let another thread piggyback onto this |
1383 | * transaction. Keep doing that while new threads continue to | |
1384 | * arrive. It doesn't cost much - we're about to run a commit | |
1385 | * and sleep on IO anyway. Speeds up many-threaded, many-dir | |
1386 | * operations by 30x or more... | |
1387 | * | |
1388 | * We try and optimize the sleep time against what the | |
1389 | * underlying disk can do, instead of having a static sleep | |
1390 | * time. This is useful for the case where our storage is so | |
1391 | * fast that it is more optimal to go ahead and force a flush | |
1392 | * and wait for the transaction to be committed than it is to | |
1393 | * wait for an arbitrary amount of time for new writers to | |
1394 | * join the transaction. We achieve this by measuring how | |
1395 | * long it takes to commit a transaction, and compare it with | |
1396 | * how long this transaction has been running, and if run time | |
1397 | * < commit time then we sleep for the delta and commit. This | |
1398 | * greatly helps super fast disks that would see slowdowns as | |
1399 | * more threads started doing fsyncs. | |
470decc6 | 1400 | * |
e07f7183 JB |
1401 | * But don't do this if this process was the most recent one |
1402 | * to perform a synchronous write. We do this to detect the | |
1403 | * case where a single process is doing a stream of sync | |
1404 | * writes. No point in waiting for joiners in that case. | |
470decc6 DK |
1405 | */ |
1406 | pid = current->pid; | |
1407 | if (handle->h_sync && journal->j_last_sync_writer != pid) { | |
e07f7183 JB |
1408 | u64 commit_time, trans_time; |
1409 | ||
470decc6 | 1410 | journal->j_last_sync_writer = pid; |
e07f7183 | 1411 | |
a931da6a | 1412 | read_lock(&journal->j_state_lock); |
e07f7183 | 1413 | commit_time = journal->j_average_commit_time; |
a931da6a | 1414 | read_unlock(&journal->j_state_lock); |
e07f7183 JB |
1415 | |
1416 | trans_time = ktime_to_ns(ktime_sub(ktime_get(), | |
1417 | transaction->t_start_time)); | |
1418 | ||
30773840 TT |
1419 | commit_time = max_t(u64, commit_time, |
1420 | 1000*journal->j_min_batch_time); | |
e07f7183 | 1421 | commit_time = min_t(u64, commit_time, |
30773840 | 1422 | 1000*journal->j_max_batch_time); |
e07f7183 JB |
1423 | |
1424 | if (trans_time < commit_time) { | |
1425 | ktime_t expires = ktime_add_ns(ktime_get(), | |
1426 | commit_time); | |
1427 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1428 | schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); | |
1429 | } | |
470decc6 DK |
1430 | } |
1431 | ||
7058548c TT |
1432 | if (handle->h_sync) |
1433 | transaction->t_synchronous_commit = 1; | |
470decc6 | 1434 | current->journal_info = NULL; |
a51dca9c TT |
1435 | atomic_sub(handle->h_buffer_credits, |
1436 | &transaction->t_outstanding_credits); | |
470decc6 DK |
1437 | |
1438 | /* | |
1439 | * If the handle is marked SYNC, we need to set another commit | |
1440 | * going! We also want to force a commit if the current | |
1441 | * transaction is occupying too much of the log, or if the | |
1442 | * transaction is too old now. | |
1443 | */ | |
1444 | if (handle->h_sync || | |
a51dca9c TT |
1445 | (atomic_read(&transaction->t_outstanding_credits) > |
1446 | journal->j_max_transaction_buffers) || | |
1447 | time_after_eq(jiffies, transaction->t_expires)) { | |
470decc6 DK |
1448 | /* Do this even for aborted journals: an abort still |
1449 | * completes the commit thread, it just doesn't write | |
1450 | * anything to disk. */ | |
470decc6 | 1451 | |
470decc6 DK |
1452 | jbd_debug(2, "transaction too old, requesting commit for " |
1453 | "handle %p\n", handle); | |
1454 | /* This is non-blocking */ | |
c35a56a0 | 1455 | jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
1456 | |
1457 | /* | |
f7f4bccb | 1458 | * Special case: JBD2_SYNC synchronous updates require us |
470decc6 DK |
1459 | * to wait for the commit to complete. |
1460 | */ | |
1461 | if (handle->h_sync && !(current->flags & PF_MEMALLOC)) | |
a51dca9c | 1462 | wait_for_commit = 1; |
470decc6 DK |
1463 | } |
1464 | ||
a51dca9c TT |
1465 | /* |
1466 | * Once we drop t_updates, if it goes to zero the transaction | |
25985edc | 1467 | * could start committing on us and eventually disappear. So |
a51dca9c TT |
1468 | * once we do this, we must not dereference transaction |
1469 | * pointer again. | |
1470 | */ | |
1471 | tid = transaction->t_tid; | |
1472 | if (atomic_dec_and_test(&transaction->t_updates)) { | |
1473 | wake_up(&journal->j_wait_updates); | |
1474 | if (journal->j_barrier_count) | |
1475 | wake_up(&journal->j_wait_transaction_locked); | |
1476 | } | |
1477 | ||
1478 | if (wait_for_commit) | |
1479 | err = jbd2_log_wait_commit(journal, tid); | |
1480 | ||
3295f0ef | 1481 | lock_map_release(&handle->h_lockdep_map); |
7b751066 | 1482 | |
af1e76d6 | 1483 | jbd2_free_handle(handle); |
470decc6 DK |
1484 | return err; |
1485 | } | |
1486 | ||
5648ba5b RD |
1487 | /** |
1488 | * int jbd2_journal_force_commit() - force any uncommitted transactions | |
470decc6 DK |
1489 | * @journal: journal to force |
1490 | * | |
1491 | * For synchronous operations: force any uncommitted transactions | |
1492 | * to disk. May seem kludgy, but it reuses all the handle batching | |
1493 | * code in a very simple manner. | |
1494 | */ | |
f7f4bccb | 1495 | int jbd2_journal_force_commit(journal_t *journal) |
470decc6 DK |
1496 | { |
1497 | handle_t *handle; | |
1498 | int ret; | |
1499 | ||
f7f4bccb | 1500 | handle = jbd2_journal_start(journal, 1); |
470decc6 DK |
1501 | if (IS_ERR(handle)) { |
1502 | ret = PTR_ERR(handle); | |
1503 | } else { | |
1504 | handle->h_sync = 1; | |
f7f4bccb | 1505 | ret = jbd2_journal_stop(handle); |
470decc6 DK |
1506 | } |
1507 | return ret; | |
1508 | } | |
1509 | ||
1510 | /* | |
1511 | * | |
1512 | * List management code snippets: various functions for manipulating the | |
1513 | * transaction buffer lists. | |
1514 | * | |
1515 | */ | |
1516 | ||
1517 | /* | |
1518 | * Append a buffer to a transaction list, given the transaction's list head | |
1519 | * pointer. | |
1520 | * | |
1521 | * j_list_lock is held. | |
1522 | * | |
1523 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1524 | */ | |
1525 | ||
1526 | static inline void | |
1527 | __blist_add_buffer(struct journal_head **list, struct journal_head *jh) | |
1528 | { | |
1529 | if (!*list) { | |
1530 | jh->b_tnext = jh->b_tprev = jh; | |
1531 | *list = jh; | |
1532 | } else { | |
1533 | /* Insert at the tail of the list to preserve order */ | |
1534 | struct journal_head *first = *list, *last = first->b_tprev; | |
1535 | jh->b_tprev = last; | |
1536 | jh->b_tnext = first; | |
1537 | last->b_tnext = first->b_tprev = jh; | |
1538 | } | |
1539 | } | |
1540 | ||
1541 | /* | |
1542 | * Remove a buffer from a transaction list, given the transaction's list | |
1543 | * head pointer. | |
1544 | * | |
1545 | * Called with j_list_lock held, and the journal may not be locked. | |
1546 | * | |
1547 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1548 | */ | |
1549 | ||
1550 | static inline void | |
1551 | __blist_del_buffer(struct journal_head **list, struct journal_head *jh) | |
1552 | { | |
1553 | if (*list == jh) { | |
1554 | *list = jh->b_tnext; | |
1555 | if (*list == jh) | |
1556 | *list = NULL; | |
1557 | } | |
1558 | jh->b_tprev->b_tnext = jh->b_tnext; | |
1559 | jh->b_tnext->b_tprev = jh->b_tprev; | |
1560 | } | |
1561 | ||
1562 | /* | |
1563 | * Remove a buffer from the appropriate transaction list. | |
1564 | * | |
1565 | * Note that this function can *change* the value of | |
87c89c23 JK |
1566 | * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list, |
1567 | * t_log_list or t_reserved_list. If the caller is holding onto a copy of one | |
1568 | * of these pointers, it could go bad. Generally the caller needs to re-read | |
1569 | * the pointer from the transaction_t. | |
470decc6 | 1570 | * |
5bebccf9 | 1571 | * Called under j_list_lock. |
470decc6 | 1572 | */ |
5bebccf9 | 1573 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
470decc6 DK |
1574 | { |
1575 | struct journal_head **list = NULL; | |
1576 | transaction_t *transaction; | |
1577 | struct buffer_head *bh = jh2bh(jh); | |
1578 | ||
1579 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1580 | transaction = jh->b_transaction; | |
1581 | if (transaction) | |
1582 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1583 | ||
1584 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1585 | if (jh->b_jlist != BJ_None) | |
4019191b | 1586 | J_ASSERT_JH(jh, transaction != NULL); |
470decc6 DK |
1587 | |
1588 | switch (jh->b_jlist) { | |
1589 | case BJ_None: | |
1590 | return; | |
470decc6 DK |
1591 | case BJ_Metadata: |
1592 | transaction->t_nr_buffers--; | |
1593 | J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); | |
1594 | list = &transaction->t_buffers; | |
1595 | break; | |
1596 | case BJ_Forget: | |
1597 | list = &transaction->t_forget; | |
1598 | break; | |
1599 | case BJ_IO: | |
1600 | list = &transaction->t_iobuf_list; | |
1601 | break; | |
1602 | case BJ_Shadow: | |
1603 | list = &transaction->t_shadow_list; | |
1604 | break; | |
1605 | case BJ_LogCtl: | |
1606 | list = &transaction->t_log_list; | |
1607 | break; | |
1608 | case BJ_Reserved: | |
1609 | list = &transaction->t_reserved_list; | |
1610 | break; | |
470decc6 DK |
1611 | } |
1612 | ||
1613 | __blist_del_buffer(list, jh); | |
1614 | jh->b_jlist = BJ_None; | |
1615 | if (test_clear_buffer_jbddirty(bh)) | |
1616 | mark_buffer_dirty(bh); /* Expose it to the VM */ | |
1617 | } | |
1618 | ||
de1b7941 JK |
1619 | /* |
1620 | * Remove buffer from all transactions. | |
1621 | * | |
1622 | * Called with bh_state lock and j_list_lock | |
1623 | * | |
1624 | * jh and bh may be already freed when this function returns. | |
1625 | */ | |
1626 | static void __jbd2_journal_unfile_buffer(struct journal_head *jh) | |
470decc6 | 1627 | { |
f7f4bccb | 1628 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 | 1629 | jh->b_transaction = NULL; |
de1b7941 | 1630 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1631 | } |
1632 | ||
f7f4bccb | 1633 | void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 | 1634 | { |
de1b7941 JK |
1635 | struct buffer_head *bh = jh2bh(jh); |
1636 | ||
1637 | /* Get reference so that buffer cannot be freed before we unlock it */ | |
1638 | get_bh(bh); | |
1639 | jbd_lock_bh_state(bh); | |
470decc6 | 1640 | spin_lock(&journal->j_list_lock); |
f7f4bccb | 1641 | __jbd2_journal_unfile_buffer(jh); |
470decc6 | 1642 | spin_unlock(&journal->j_list_lock); |
de1b7941 JK |
1643 | jbd_unlock_bh_state(bh); |
1644 | __brelse(bh); | |
470decc6 DK |
1645 | } |
1646 | ||
1647 | /* | |
f7f4bccb | 1648 | * Called from jbd2_journal_try_to_free_buffers(). |
470decc6 DK |
1649 | * |
1650 | * Called under jbd_lock_bh_state(bh) | |
1651 | */ | |
1652 | static void | |
1653 | __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) | |
1654 | { | |
1655 | struct journal_head *jh; | |
1656 | ||
1657 | jh = bh2jh(bh); | |
1658 | ||
1659 | if (buffer_locked(bh) || buffer_dirty(bh)) | |
1660 | goto out; | |
1661 | ||
4019191b | 1662 | if (jh->b_next_transaction != NULL) |
470decc6 DK |
1663 | goto out; |
1664 | ||
1665 | spin_lock(&journal->j_list_lock); | |
87c89c23 | 1666 | if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) { |
470decc6 | 1667 | /* written-back checkpointed metadata buffer */ |
c254c9ec JK |
1668 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
1669 | __jbd2_journal_remove_checkpoint(jh); | |
470decc6 DK |
1670 | } |
1671 | spin_unlock(&journal->j_list_lock); | |
1672 | out: | |
1673 | return; | |
1674 | } | |
1675 | ||
470decc6 | 1676 | /** |
f7f4bccb | 1677 | * int jbd2_journal_try_to_free_buffers() - try to free page buffers. |
470decc6 DK |
1678 | * @journal: journal for operation |
1679 | * @page: to try and free | |
530576bb MC |
1680 | * @gfp_mask: we use the mask to detect how hard should we try to release |
1681 | * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to | |
1682 | * release the buffers. | |
470decc6 DK |
1683 | * |
1684 | * | |
1685 | * For all the buffers on this page, | |
1686 | * if they are fully written out ordered data, move them onto BUF_CLEAN | |
1687 | * so try_to_free_buffers() can reap them. | |
1688 | * | |
1689 | * This function returns non-zero if we wish try_to_free_buffers() | |
1690 | * to be called. We do this if the page is releasable by try_to_free_buffers(). | |
1691 | * We also do it if the page has locked or dirty buffers and the caller wants | |
1692 | * us to perform sync or async writeout. | |
1693 | * | |
1694 | * This complicates JBD locking somewhat. We aren't protected by the | |
1695 | * BKL here. We wish to remove the buffer from its committing or | |
f7f4bccb | 1696 | * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
470decc6 DK |
1697 | * |
1698 | * This may *change* the value of transaction_t->t_datalist, so anyone | |
1699 | * who looks at t_datalist needs to lock against this function. | |
1700 | * | |
f7f4bccb MC |
1701 | * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
1702 | * buffer. So we need to lock against that. jbd2_journal_dirty_data() | |
470decc6 DK |
1703 | * will come out of the lock with the buffer dirty, which makes it |
1704 | * ineligible for release here. | |
1705 | * | |
1706 | * Who else is affected by this? hmm... Really the only contender | |
1707 | * is do_get_write_access() - it could be looking at the buffer while | |
1708 | * journal_try_to_free_buffer() is changing its state. But that | |
1709 | * cannot happen because we never reallocate freed data as metadata | |
1710 | * while the data is part of a transaction. Yes? | |
530576bb MC |
1711 | * |
1712 | * Return 0 on failure, 1 on success | |
470decc6 | 1713 | */ |
f7f4bccb | 1714 | int jbd2_journal_try_to_free_buffers(journal_t *journal, |
530576bb | 1715 | struct page *page, gfp_t gfp_mask) |
470decc6 DK |
1716 | { |
1717 | struct buffer_head *head; | |
1718 | struct buffer_head *bh; | |
1719 | int ret = 0; | |
1720 | ||
1721 | J_ASSERT(PageLocked(page)); | |
1722 | ||
1723 | head = page_buffers(page); | |
1724 | bh = head; | |
1725 | do { | |
1726 | struct journal_head *jh; | |
1727 | ||
1728 | /* | |
1729 | * We take our own ref against the journal_head here to avoid | |
1730 | * having to add tons of locking around each instance of | |
530576bb | 1731 | * jbd2_journal_put_journal_head(). |
470decc6 | 1732 | */ |
f7f4bccb | 1733 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1734 | if (!jh) |
1735 | continue; | |
1736 | ||
1737 | jbd_lock_bh_state(bh); | |
1738 | __journal_try_to_free_buffer(journal, bh); | |
f7f4bccb | 1739 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1740 | jbd_unlock_bh_state(bh); |
1741 | if (buffer_jbd(bh)) | |
1742 | goto busy; | |
1743 | } while ((bh = bh->b_this_page) != head); | |
530576bb | 1744 | |
470decc6 | 1745 | ret = try_to_free_buffers(page); |
530576bb | 1746 | |
470decc6 DK |
1747 | busy: |
1748 | return ret; | |
1749 | } | |
1750 | ||
1751 | /* | |
1752 | * This buffer is no longer needed. If it is on an older transaction's | |
1753 | * checkpoint list we need to record it on this transaction's forget list | |
1754 | * to pin this buffer (and hence its checkpointing transaction) down until | |
1755 | * this transaction commits. If the buffer isn't on a checkpoint list, we | |
1756 | * release it. | |
1757 | * Returns non-zero if JBD no longer has an interest in the buffer. | |
1758 | * | |
1759 | * Called under j_list_lock. | |
1760 | * | |
1761 | * Called under jbd_lock_bh_state(bh). | |
1762 | */ | |
1763 | static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) | |
1764 | { | |
1765 | int may_free = 1; | |
1766 | struct buffer_head *bh = jh2bh(jh); | |
1767 | ||
470decc6 DK |
1768 | if (jh->b_cp_transaction) { |
1769 | JBUFFER_TRACE(jh, "on running+cp transaction"); | |
de1b7941 | 1770 | __jbd2_journal_temp_unlink_buffer(jh); |
f91d1d04 JK |
1771 | /* |
1772 | * We don't want to write the buffer anymore, clear the | |
1773 | * bit so that we don't confuse checks in | |
1774 | * __journal_file_buffer | |
1775 | */ | |
1776 | clear_buffer_dirty(bh); | |
f7f4bccb | 1777 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
470decc6 DK |
1778 | may_free = 0; |
1779 | } else { | |
1780 | JBUFFER_TRACE(jh, "on running transaction"); | |
de1b7941 | 1781 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1782 | } |
1783 | return may_free; | |
1784 | } | |
1785 | ||
1786 | /* | |
f7f4bccb | 1787 | * jbd2_journal_invalidatepage |
470decc6 DK |
1788 | * |
1789 | * This code is tricky. It has a number of cases to deal with. | |
1790 | * | |
1791 | * There are two invariants which this code relies on: | |
1792 | * | |
1793 | * i_size must be updated on disk before we start calling invalidatepage on the | |
1794 | * data. | |
1795 | * | |
1796 | * This is done in ext3 by defining an ext3_setattr method which | |
1797 | * updates i_size before truncate gets going. By maintaining this | |
1798 | * invariant, we can be sure that it is safe to throw away any buffers | |
1799 | * attached to the current transaction: once the transaction commits, | |
1800 | * we know that the data will not be needed. | |
1801 | * | |
1802 | * Note however that we can *not* throw away data belonging to the | |
1803 | * previous, committing transaction! | |
1804 | * | |
1805 | * Any disk blocks which *are* part of the previous, committing | |
1806 | * transaction (and which therefore cannot be discarded immediately) are | |
1807 | * not going to be reused in the new running transaction | |
1808 | * | |
1809 | * The bitmap committed_data images guarantee this: any block which is | |
1810 | * allocated in one transaction and removed in the next will be marked | |
1811 | * as in-use in the committed_data bitmap, so cannot be reused until | |
1812 | * the next transaction to delete the block commits. This means that | |
1813 | * leaving committing buffers dirty is quite safe: the disk blocks | |
1814 | * cannot be reallocated to a different file and so buffer aliasing is | |
1815 | * not possible. | |
1816 | * | |
1817 | * | |
1818 | * The above applies mainly to ordered data mode. In writeback mode we | |
1819 | * don't make guarantees about the order in which data hits disk --- in | |
1820 | * particular we don't guarantee that new dirty data is flushed before | |
1821 | * transaction commit --- so it is always safe just to discard data | |
1822 | * immediately in that mode. --sct | |
1823 | */ | |
1824 | ||
1825 | /* | |
1826 | * The journal_unmap_buffer helper function returns zero if the buffer | |
1827 | * concerned remains pinned as an anonymous buffer belonging to an older | |
1828 | * transaction. | |
1829 | * | |
1830 | * We're outside-transaction here. Either or both of j_running_transaction | |
1831 | * and j_committing_transaction may be NULL. | |
1832 | */ | |
b794e7a6 JK |
1833 | static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, |
1834 | int partial_page) | |
470decc6 DK |
1835 | { |
1836 | transaction_t *transaction; | |
1837 | struct journal_head *jh; | |
1838 | int may_free = 1; | |
470decc6 DK |
1839 | |
1840 | BUFFER_TRACE(bh, "entry"); | |
1841 | ||
b794e7a6 | 1842 | retry: |
470decc6 DK |
1843 | /* |
1844 | * It is safe to proceed here without the j_list_lock because the | |
1845 | * buffers cannot be stolen by try_to_free_buffers as long as we are | |
1846 | * holding the page lock. --sct | |
1847 | */ | |
1848 | ||
1849 | if (!buffer_jbd(bh)) | |
1850 | goto zap_buffer_unlocked; | |
1851 | ||
87c89c23 | 1852 | /* OK, we have data buffer in journaled mode */ |
a931da6a | 1853 | write_lock(&journal->j_state_lock); |
470decc6 DK |
1854 | jbd_lock_bh_state(bh); |
1855 | spin_lock(&journal->j_list_lock); | |
1856 | ||
f7f4bccb | 1857 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1858 | if (!jh) |
1859 | goto zap_buffer_no_jh; | |
1860 | ||
ba869023 | 1861 | /* |
1862 | * We cannot remove the buffer from checkpoint lists until the | |
1863 | * transaction adding inode to orphan list (let's call it T) | |
1864 | * is committed. Otherwise if the transaction changing the | |
1865 | * buffer would be cleaned from the journal before T is | |
1866 | * committed, a crash will cause that the correct contents of | |
1867 | * the buffer will be lost. On the other hand we have to | |
1868 | * clear the buffer dirty bit at latest at the moment when the | |
1869 | * transaction marking the buffer as freed in the filesystem | |
1870 | * structures is committed because from that moment on the | |
b794e7a6 | 1871 | * block can be reallocated and used by a different page. |
ba869023 | 1872 | * Since the block hasn't been freed yet but the inode has |
1873 | * already been added to orphan list, it is safe for us to add | |
1874 | * the buffer to BJ_Forget list of the newest transaction. | |
b794e7a6 JK |
1875 | * |
1876 | * Also we have to clear buffer_mapped flag of a truncated buffer | |
1877 | * because the buffer_head may be attached to the page straddling | |
1878 | * i_size (can happen only when blocksize < pagesize) and thus the | |
1879 | * buffer_head can be reused when the file is extended again. So we end | |
1880 | * up keeping around invalidated buffers attached to transactions' | |
1881 | * BJ_Forget list just to stop checkpointing code from cleaning up | |
1882 | * the transaction this buffer was modified in. | |
ba869023 | 1883 | */ |
470decc6 DK |
1884 | transaction = jh->b_transaction; |
1885 | if (transaction == NULL) { | |
1886 | /* First case: not on any transaction. If it | |
1887 | * has no checkpoint link, then we can zap it: | |
1888 | * it's a writeback-mode buffer so we don't care | |
1889 | * if it hits disk safely. */ | |
1890 | if (!jh->b_cp_transaction) { | |
1891 | JBUFFER_TRACE(jh, "not on any transaction: zap"); | |
1892 | goto zap_buffer; | |
1893 | } | |
1894 | ||
1895 | if (!buffer_dirty(bh)) { | |
1896 | /* bdflush has written it. We can drop it now */ | |
1897 | goto zap_buffer; | |
1898 | } | |
1899 | ||
1900 | /* OK, it must be in the journal but still not | |
1901 | * written fully to disk: it's metadata or | |
1902 | * journaled data... */ | |
1903 | ||
1904 | if (journal->j_running_transaction) { | |
1905 | /* ... and once the current transaction has | |
1906 | * committed, the buffer won't be needed any | |
1907 | * longer. */ | |
1908 | JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); | |
b794e7a6 | 1909 | may_free = __dispose_buffer(jh, |
470decc6 | 1910 | journal->j_running_transaction); |
b794e7a6 | 1911 | goto zap_buffer; |
470decc6 DK |
1912 | } else { |
1913 | /* There is no currently-running transaction. So the | |
1914 | * orphan record which we wrote for this file must have | |
1915 | * passed into commit. We must attach this buffer to | |
1916 | * the committing transaction, if it exists. */ | |
1917 | if (journal->j_committing_transaction) { | |
1918 | JBUFFER_TRACE(jh, "give to committing trans"); | |
b794e7a6 | 1919 | may_free = __dispose_buffer(jh, |
470decc6 | 1920 | journal->j_committing_transaction); |
b794e7a6 | 1921 | goto zap_buffer; |
470decc6 DK |
1922 | } else { |
1923 | /* The orphan record's transaction has | |
1924 | * committed. We can cleanse this buffer */ | |
1925 | clear_buffer_jbddirty(bh); | |
1926 | goto zap_buffer; | |
1927 | } | |
1928 | } | |
1929 | } else if (transaction == journal->j_committing_transaction) { | |
9b57988d | 1930 | JBUFFER_TRACE(jh, "on committing transaction"); |
470decc6 | 1931 | /* |
ba869023 | 1932 | * The buffer is committing, we simply cannot touch |
b794e7a6 JK |
1933 | * it. If the page is straddling i_size we have to wait |
1934 | * for commit and try again. | |
1935 | */ | |
1936 | if (partial_page) { | |
1937 | tid_t tid = journal->j_committing_transaction->t_tid; | |
1938 | ||
1939 | jbd2_journal_put_journal_head(jh); | |
1940 | spin_unlock(&journal->j_list_lock); | |
1941 | jbd_unlock_bh_state(bh); | |
1942 | write_unlock(&journal->j_state_lock); | |
1943 | jbd2_log_wait_commit(journal, tid); | |
1944 | goto retry; | |
1945 | } | |
1946 | /* | |
1947 | * OK, buffer won't be reachable after truncate. We just set | |
1948 | * j_next_transaction to the running transaction (if there is | |
1949 | * one) and mark buffer as freed so that commit code knows it | |
1950 | * should clear dirty bits when it is done with the buffer. | |
ba869023 | 1951 | */ |
470decc6 | 1952 | set_buffer_freed(bh); |
ba869023 | 1953 | if (journal->j_running_transaction && buffer_jbddirty(bh)) |
1954 | jh->b_next_transaction = journal->j_running_transaction; | |
f7f4bccb | 1955 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1956 | spin_unlock(&journal->j_list_lock); |
1957 | jbd_unlock_bh_state(bh); | |
a931da6a | 1958 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1959 | return 0; |
1960 | } else { | |
1961 | /* Good, the buffer belongs to the running transaction. | |
1962 | * We are writing our own transaction's data, not any | |
1963 | * previous one's, so it is safe to throw it away | |
1964 | * (remember that we expect the filesystem to have set | |
1965 | * i_size already for this truncate so recovery will not | |
1966 | * expose the disk blocks we are discarding here.) */ | |
1967 | J_ASSERT_JH(jh, transaction == journal->j_running_transaction); | |
9b57988d | 1968 | JBUFFER_TRACE(jh, "on running transaction"); |
470decc6 DK |
1969 | may_free = __dispose_buffer(jh, transaction); |
1970 | } | |
1971 | ||
1972 | zap_buffer: | |
b794e7a6 JK |
1973 | /* |
1974 | * This is tricky. Although the buffer is truncated, it may be reused | |
1975 | * if blocksize < pagesize and it is attached to the page straddling | |
1976 | * EOF. Since the buffer might have been added to BJ_Forget list of the | |
1977 | * running transaction, journal_get_write_access() won't clear | |
1978 | * b_modified and credit accounting gets confused. So clear b_modified | |
1979 | * here. | |
1980 | */ | |
1981 | jh->b_modified = 0; | |
f7f4bccb | 1982 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1983 | zap_buffer_no_jh: |
1984 | spin_unlock(&journal->j_list_lock); | |
1985 | jbd_unlock_bh_state(bh); | |
a931da6a | 1986 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1987 | zap_buffer_unlocked: |
1988 | clear_buffer_dirty(bh); | |
1989 | J_ASSERT_BH(bh, !buffer_jbddirty(bh)); | |
1990 | clear_buffer_mapped(bh); | |
1991 | clear_buffer_req(bh); | |
1992 | clear_buffer_new(bh); | |
15291164 ES |
1993 | clear_buffer_delay(bh); |
1994 | clear_buffer_unwritten(bh); | |
470decc6 DK |
1995 | bh->b_bdev = NULL; |
1996 | return may_free; | |
1997 | } | |
1998 | ||
1999 | /** | |
f7f4bccb | 2000 | * void jbd2_journal_invalidatepage() |
470decc6 DK |
2001 | * @journal: journal to use for flush... |
2002 | * @page: page to flush | |
2003 | * @offset: length of page to invalidate. | |
2004 | * | |
2005 | * Reap page buffers containing data after offset in page. | |
2006 | * | |
2007 | */ | |
f7f4bccb | 2008 | void jbd2_journal_invalidatepage(journal_t *journal, |
470decc6 DK |
2009 | struct page *page, |
2010 | unsigned long offset) | |
2011 | { | |
2012 | struct buffer_head *head, *bh, *next; | |
2013 | unsigned int curr_off = 0; | |
2014 | int may_free = 1; | |
2015 | ||
2016 | if (!PageLocked(page)) | |
2017 | BUG(); | |
2018 | if (!page_has_buffers(page)) | |
2019 | return; | |
2020 | ||
2021 | /* We will potentially be playing with lists other than just the | |
2022 | * data lists (especially for journaled data mode), so be | |
2023 | * cautious in our locking. */ | |
2024 | ||
2025 | head = bh = page_buffers(page); | |
2026 | do { | |
2027 | unsigned int next_off = curr_off + bh->b_size; | |
2028 | next = bh->b_this_page; | |
2029 | ||
2030 | if (offset <= curr_off) { | |
2031 | /* This block is wholly outside the truncation point */ | |
2032 | lock_buffer(bh); | |
b794e7a6 JK |
2033 | may_free &= journal_unmap_buffer(journal, bh, |
2034 | offset > 0); | |
470decc6 DK |
2035 | unlock_buffer(bh); |
2036 | } | |
2037 | curr_off = next_off; | |
2038 | bh = next; | |
2039 | ||
2040 | } while (bh != head); | |
2041 | ||
2042 | if (!offset) { | |
2043 | if (may_free && try_to_free_buffers(page)) | |
2044 | J_ASSERT(!page_has_buffers(page)); | |
2045 | } | |
2046 | } | |
2047 | ||
2048 | /* | |
2049 | * File a buffer on the given transaction list. | |
2050 | */ | |
f7f4bccb | 2051 | void __jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2052 | transaction_t *transaction, int jlist) |
2053 | { | |
2054 | struct journal_head **list = NULL; | |
2055 | int was_dirty = 0; | |
2056 | struct buffer_head *bh = jh2bh(jh); | |
2057 | ||
2058 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
2059 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
2060 | ||
2061 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
2062 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
4019191b | 2063 | jh->b_transaction == NULL); |
470decc6 DK |
2064 | |
2065 | if (jh->b_transaction && jh->b_jlist == jlist) | |
2066 | return; | |
2067 | ||
470decc6 DK |
2068 | if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
2069 | jlist == BJ_Shadow || jlist == BJ_Forget) { | |
f91d1d04 JK |
2070 | /* |
2071 | * For metadata buffers, we track dirty bit in buffer_jbddirty | |
2072 | * instead of buffer_dirty. We should not see a dirty bit set | |
2073 | * here because we clear it in do_get_write_access but e.g. | |
2074 | * tune2fs can modify the sb and set the dirty bit at any time | |
2075 | * so we try to gracefully handle that. | |
2076 | */ | |
2077 | if (buffer_dirty(bh)) | |
2078 | warn_dirty_buffer(bh); | |
470decc6 DK |
2079 | if (test_clear_buffer_dirty(bh) || |
2080 | test_clear_buffer_jbddirty(bh)) | |
2081 | was_dirty = 1; | |
2082 | } | |
2083 | ||
2084 | if (jh->b_transaction) | |
f7f4bccb | 2085 | __jbd2_journal_temp_unlink_buffer(jh); |
de1b7941 JK |
2086 | else |
2087 | jbd2_journal_grab_journal_head(bh); | |
470decc6 DK |
2088 | jh->b_transaction = transaction; |
2089 | ||
2090 | switch (jlist) { | |
2091 | case BJ_None: | |
2092 | J_ASSERT_JH(jh, !jh->b_committed_data); | |
2093 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
2094 | return; | |
470decc6 DK |
2095 | case BJ_Metadata: |
2096 | transaction->t_nr_buffers++; | |
2097 | list = &transaction->t_buffers; | |
2098 | break; | |
2099 | case BJ_Forget: | |
2100 | list = &transaction->t_forget; | |
2101 | break; | |
2102 | case BJ_IO: | |
2103 | list = &transaction->t_iobuf_list; | |
2104 | break; | |
2105 | case BJ_Shadow: | |
2106 | list = &transaction->t_shadow_list; | |
2107 | break; | |
2108 | case BJ_LogCtl: | |
2109 | list = &transaction->t_log_list; | |
2110 | break; | |
2111 | case BJ_Reserved: | |
2112 | list = &transaction->t_reserved_list; | |
2113 | break; | |
470decc6 DK |
2114 | } |
2115 | ||
2116 | __blist_add_buffer(list, jh); | |
2117 | jh->b_jlist = jlist; | |
2118 | ||
2119 | if (was_dirty) | |
2120 | set_buffer_jbddirty(bh); | |
2121 | } | |
2122 | ||
f7f4bccb | 2123 | void jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2124 | transaction_t *transaction, int jlist) |
2125 | { | |
2126 | jbd_lock_bh_state(jh2bh(jh)); | |
2127 | spin_lock(&transaction->t_journal->j_list_lock); | |
f7f4bccb | 2128 | __jbd2_journal_file_buffer(jh, transaction, jlist); |
470decc6 DK |
2129 | spin_unlock(&transaction->t_journal->j_list_lock); |
2130 | jbd_unlock_bh_state(jh2bh(jh)); | |
2131 | } | |
2132 | ||
2133 | /* | |
2134 | * Remove a buffer from its current buffer list in preparation for | |
2135 | * dropping it from its current transaction entirely. If the buffer has | |
2136 | * already started to be used by a subsequent transaction, refile the | |
2137 | * buffer on that transaction's metadata list. | |
2138 | * | |
de1b7941 | 2139 | * Called under j_list_lock |
470decc6 | 2140 | * Called under jbd_lock_bh_state(jh2bh(jh)) |
de1b7941 JK |
2141 | * |
2142 | * jh and bh may be already free when this function returns | |
470decc6 | 2143 | */ |
f7f4bccb | 2144 | void __jbd2_journal_refile_buffer(struct journal_head *jh) |
470decc6 | 2145 | { |
ba869023 | 2146 | int was_dirty, jlist; |
470decc6 DK |
2147 | struct buffer_head *bh = jh2bh(jh); |
2148 | ||
2149 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
2150 | if (jh->b_transaction) | |
2151 | assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); | |
2152 | ||
2153 | /* If the buffer is now unused, just drop it. */ | |
2154 | if (jh->b_next_transaction == NULL) { | |
f7f4bccb | 2155 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
2156 | return; |
2157 | } | |
2158 | ||
2159 | /* | |
2160 | * It has been modified by a later transaction: add it to the new | |
2161 | * transaction's metadata list. | |
2162 | */ | |
2163 | ||
2164 | was_dirty = test_clear_buffer_jbddirty(bh); | |
f7f4bccb | 2165 | __jbd2_journal_temp_unlink_buffer(jh); |
de1b7941 JK |
2166 | /* |
2167 | * We set b_transaction here because b_next_transaction will inherit | |
2168 | * our jh reference and thus __jbd2_journal_file_buffer() must not | |
2169 | * take a new one. | |
2170 | */ | |
470decc6 DK |
2171 | jh->b_transaction = jh->b_next_transaction; |
2172 | jh->b_next_transaction = NULL; | |
ba869023 | 2173 | if (buffer_freed(bh)) |
2174 | jlist = BJ_Forget; | |
2175 | else if (jh->b_modified) | |
2176 | jlist = BJ_Metadata; | |
2177 | else | |
2178 | jlist = BJ_Reserved; | |
2179 | __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist); | |
470decc6 DK |
2180 | J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
2181 | ||
2182 | if (was_dirty) | |
2183 | set_buffer_jbddirty(bh); | |
2184 | } | |
2185 | ||
2186 | /* | |
de1b7941 JK |
2187 | * __jbd2_journal_refile_buffer() with necessary locking added. We take our |
2188 | * bh reference so that we can safely unlock bh. | |
2189 | * | |
2190 | * The jh and bh may be freed by this call. | |
470decc6 | 2191 | */ |
f7f4bccb | 2192 | void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
2193 | { |
2194 | struct buffer_head *bh = jh2bh(jh); | |
2195 | ||
de1b7941 JK |
2196 | /* Get reference so that buffer cannot be freed before we unlock it */ |
2197 | get_bh(bh); | |
470decc6 DK |
2198 | jbd_lock_bh_state(bh); |
2199 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 2200 | __jbd2_journal_refile_buffer(jh); |
470decc6 | 2201 | jbd_unlock_bh_state(bh); |
470decc6 DK |
2202 | spin_unlock(&journal->j_list_lock); |
2203 | __brelse(bh); | |
2204 | } | |
c851ed54 JK |
2205 | |
2206 | /* | |
2207 | * File inode in the inode list of the handle's transaction | |
2208 | */ | |
2209 | int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode) | |
2210 | { | |
2211 | transaction_t *transaction = handle->h_transaction; | |
2212 | journal_t *journal = transaction->t_journal; | |
2213 | ||
2214 | if (is_handle_aborted(handle)) | |
2215 | return -EIO; | |
2216 | ||
2217 | jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, | |
2218 | transaction->t_tid); | |
2219 | ||
2220 | /* | |
2221 | * First check whether inode isn't already on the transaction's | |
2222 | * lists without taking the lock. Note that this check is safe | |
2223 | * without the lock as we cannot race with somebody removing inode | |
2224 | * from the transaction. The reason is that we remove inode from the | |
2225 | * transaction only in journal_release_jbd_inode() and when we commit | |
2226 | * the transaction. We are guarded from the first case by holding | |
2227 | * a reference to the inode. We are safe against the second case | |
2228 | * because if jinode->i_transaction == transaction, commit code | |
2229 | * cannot touch the transaction because we hold reference to it, | |
2230 | * and if jinode->i_next_transaction == transaction, commit code | |
2231 | * will only file the inode where we want it. | |
2232 | */ | |
2233 | if (jinode->i_transaction == transaction || | |
2234 | jinode->i_next_transaction == transaction) | |
2235 | return 0; | |
2236 | ||
2237 | spin_lock(&journal->j_list_lock); | |
2238 | ||
2239 | if (jinode->i_transaction == transaction || | |
2240 | jinode->i_next_transaction == transaction) | |
2241 | goto done; | |
2242 | ||
81be12c8 JK |
2243 | /* |
2244 | * We only ever set this variable to 1 so the test is safe. Since | |
2245 | * t_need_data_flush is likely to be set, we do the test to save some | |
2246 | * cacheline bouncing | |
2247 | */ | |
2248 | if (!transaction->t_need_data_flush) | |
2249 | transaction->t_need_data_flush = 1; | |
c851ed54 JK |
2250 | /* On some different transaction's list - should be |
2251 | * the committing one */ | |
2252 | if (jinode->i_transaction) { | |
2253 | J_ASSERT(jinode->i_next_transaction == NULL); | |
2254 | J_ASSERT(jinode->i_transaction == | |
2255 | journal->j_committing_transaction); | |
2256 | jinode->i_next_transaction = transaction; | |
2257 | goto done; | |
2258 | } | |
2259 | /* Not on any transaction list... */ | |
2260 | J_ASSERT(!jinode->i_next_transaction); | |
2261 | jinode->i_transaction = transaction; | |
2262 | list_add(&jinode->i_list, &transaction->t_inode_list); | |
2263 | done: | |
2264 | spin_unlock(&journal->j_list_lock); | |
2265 | ||
2266 | return 0; | |
2267 | } | |
2268 | ||
2269 | /* | |
7f5aa215 JK |
2270 | * File truncate and transaction commit interact with each other in a |
2271 | * non-trivial way. If a transaction writing data block A is | |
2272 | * committing, we cannot discard the data by truncate until we have | |
2273 | * written them. Otherwise if we crashed after the transaction with | |
2274 | * write has committed but before the transaction with truncate has | |
2275 | * committed, we could see stale data in block A. This function is a | |
2276 | * helper to solve this problem. It starts writeout of the truncated | |
2277 | * part in case it is in the committing transaction. | |
2278 | * | |
2279 | * Filesystem code must call this function when inode is journaled in | |
2280 | * ordered mode before truncation happens and after the inode has been | |
2281 | * placed on orphan list with the new inode size. The second condition | |
2282 | * avoids the race that someone writes new data and we start | |
2283 | * committing the transaction after this function has been called but | |
2284 | * before a transaction for truncate is started (and furthermore it | |
2285 | * allows us to optimize the case where the addition to orphan list | |
2286 | * happens in the same transaction as write --- we don't have to write | |
2287 | * any data in such case). | |
c851ed54 | 2288 | */ |
7f5aa215 JK |
2289 | int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
2290 | struct jbd2_inode *jinode, | |
c851ed54 JK |
2291 | loff_t new_size) |
2292 | { | |
7f5aa215 | 2293 | transaction_t *inode_trans, *commit_trans; |
c851ed54 JK |
2294 | int ret = 0; |
2295 | ||
7f5aa215 JK |
2296 | /* This is a quick check to avoid locking if not necessary */ |
2297 | if (!jinode->i_transaction) | |
c851ed54 | 2298 | goto out; |
7f5aa215 JK |
2299 | /* Locks are here just to force reading of recent values, it is |
2300 | * enough that the transaction was not committing before we started | |
2301 | * a transaction adding the inode to orphan list */ | |
a931da6a | 2302 | read_lock(&journal->j_state_lock); |
c851ed54 | 2303 | commit_trans = journal->j_committing_transaction; |
a931da6a | 2304 | read_unlock(&journal->j_state_lock); |
7f5aa215 JK |
2305 | spin_lock(&journal->j_list_lock); |
2306 | inode_trans = jinode->i_transaction; | |
2307 | spin_unlock(&journal->j_list_lock); | |
2308 | if (inode_trans == commit_trans) { | |
2309 | ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, | |
c851ed54 JK |
2310 | new_size, LLONG_MAX); |
2311 | if (ret) | |
2312 | jbd2_journal_abort(journal, ret); | |
2313 | } | |
2314 | out: | |
2315 | return ret; | |
2316 | } |