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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 TT |
29 | #include <linux/backing-dev.h> |
30 | #include <linux/module.h> | |
470decc6 | 31 | |
7ddae860 AB |
32 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
33 | ||
470decc6 | 34 | /* |
f7f4bccb | 35 | * jbd2_get_transaction: obtain a new transaction_t object. |
470decc6 DK |
36 | * |
37 | * Simply allocate and initialise a new transaction. Create it in | |
38 | * RUNNING state and add it to the current journal (which should not | |
39 | * have an existing running transaction: we only make a new transaction | |
40 | * once we have started to commit the old one). | |
41 | * | |
42 | * Preconditions: | |
43 | * The journal MUST be locked. We don't perform atomic mallocs on the | |
44 | * new transaction and we can't block without protecting against other | |
45 | * processes trying to touch the journal while it is in transition. | |
46 | * | |
470decc6 DK |
47 | */ |
48 | ||
49 | static transaction_t * | |
f7f4bccb | 50 | jbd2_get_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
51 | { |
52 | transaction->t_journal = journal; | |
53 | transaction->t_state = T_RUNNING; | |
e07f7183 | 54 | transaction->t_start_time = ktime_get(); |
470decc6 DK |
55 | transaction->t_tid = journal->j_transaction_sequence++; |
56 | transaction->t_expires = jiffies + journal->j_commit_interval; | |
57 | spin_lock_init(&transaction->t_handle_lock); | |
a51dca9c TT |
58 | atomic_set(&transaction->t_updates, 0); |
59 | atomic_set(&transaction->t_outstanding_credits, 0); | |
8dd42046 | 60 | atomic_set(&transaction->t_handle_count, 0); |
c851ed54 | 61 | INIT_LIST_HEAD(&transaction->t_inode_list); |
3e624fc7 | 62 | INIT_LIST_HEAD(&transaction->t_private_list); |
470decc6 DK |
63 | |
64 | /* Set up the commit timer for the new transaction. */ | |
b1f485f2 | 65 | journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
470decc6 DK |
66 | add_timer(&journal->j_commit_timer); |
67 | ||
68 | J_ASSERT(journal->j_running_transaction == NULL); | |
69 | journal->j_running_transaction = transaction; | |
8e85fb3f JL |
70 | transaction->t_max_wait = 0; |
71 | transaction->t_start = jiffies; | |
470decc6 DK |
72 | |
73 | return transaction; | |
74 | } | |
75 | ||
76 | /* | |
77 | * Handle management. | |
78 | * | |
79 | * A handle_t is an object which represents a single atomic update to a | |
80 | * filesystem, and which tracks all of the modifications which form part | |
81 | * of that one update. | |
82 | */ | |
83 | ||
6d0bf005 TT |
84 | /* |
85 | * Update transiaction's maximum wait time, if debugging is enabled. | |
86 | * | |
87 | * In order for t_max_wait to be reliable, it must be protected by a | |
88 | * lock. But doing so will mean that start_this_handle() can not be | |
89 | * run in parallel on SMP systems, which limits our scalability. So | |
90 | * unless debugging is enabled, we no longer update t_max_wait, which | |
91 | * means that maximum wait time reported by the jbd2_run_stats | |
92 | * tracepoint will always be zero. | |
93 | */ | |
94 | static inline void update_t_max_wait(transaction_t *transaction) | |
95 | { | |
96 | #ifdef CONFIG_JBD2_DEBUG | |
97 | unsigned long ts = jiffies; | |
98 | ||
99 | if (jbd2_journal_enable_debug && | |
100 | time_after(transaction->t_start, ts)) { | |
101 | ts = jbd2_time_diff(ts, transaction->t_start); | |
102 | spin_lock(&transaction->t_handle_lock); | |
103 | if (ts > transaction->t_max_wait) | |
104 | transaction->t_max_wait = ts; | |
105 | spin_unlock(&transaction->t_handle_lock); | |
106 | } | |
107 | #endif | |
108 | } | |
109 | ||
470decc6 DK |
110 | /* |
111 | * start_this_handle: Given a handle, deal with any locking or stalling | |
112 | * needed to make sure that there is enough journal space for the handle | |
113 | * to begin. Attach the handle to a transaction and set up the | |
114 | * transaction's buffer credits. | |
115 | */ | |
116 | ||
47def826 TT |
117 | static int start_this_handle(journal_t *journal, handle_t *handle, |
118 | int gfp_mask) | |
470decc6 DK |
119 | { |
120 | transaction_t *transaction; | |
121 | int needed; | |
122 | int nblocks = handle->h_buffer_credits; | |
123 | transaction_t *new_transaction = NULL; | |
470decc6 DK |
124 | |
125 | if (nblocks > journal->j_max_transaction_buffers) { | |
126 | printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n", | |
127 | current->comm, nblocks, | |
128 | journal->j_max_transaction_buffers); | |
47def826 | 129 | return -ENOSPC; |
470decc6 DK |
130 | } |
131 | ||
132 | alloc_transaction: | |
133 | if (!journal->j_running_transaction) { | |
47def826 | 134 | new_transaction = kzalloc(sizeof(*new_transaction), gfp_mask); |
470decc6 | 135 | if (!new_transaction) { |
47def826 TT |
136 | /* |
137 | * If __GFP_FS is not present, then we may be | |
138 | * being called from inside the fs writeback | |
139 | * layer, so we MUST NOT fail. Since | |
140 | * __GFP_NOFAIL is going away, we will arrange | |
141 | * to retry the allocation ourselves. | |
142 | */ | |
143 | if ((gfp_mask & __GFP_FS) == 0) { | |
144 | congestion_wait(BLK_RW_ASYNC, HZ/50); | |
145 | goto alloc_transaction; | |
146 | } | |
147 | return -ENOMEM; | |
470decc6 | 148 | } |
470decc6 DK |
149 | } |
150 | ||
151 | jbd_debug(3, "New handle %p going live.\n", handle); | |
152 | ||
470decc6 DK |
153 | /* |
154 | * We need to hold j_state_lock until t_updates has been incremented, | |
155 | * for proper journal barrier handling | |
156 | */ | |
a931da6a TT |
157 | repeat: |
158 | read_lock(&journal->j_state_lock); | |
5c2178e7 | 159 | BUG_ON(journal->j_flags & JBD2_UNMOUNT); |
470decc6 | 160 | if (is_journal_aborted(journal) || |
f7f4bccb | 161 | (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
a931da6a | 162 | read_unlock(&journal->j_state_lock); |
47def826 TT |
163 | kfree(new_transaction); |
164 | return -EROFS; | |
470decc6 DK |
165 | } |
166 | ||
167 | /* Wait on the journal's transaction barrier if necessary */ | |
168 | if (journal->j_barrier_count) { | |
a931da6a | 169 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
170 | wait_event(journal->j_wait_transaction_locked, |
171 | journal->j_barrier_count == 0); | |
172 | goto repeat; | |
173 | } | |
174 | ||
175 | if (!journal->j_running_transaction) { | |
a931da6a TT |
176 | read_unlock(&journal->j_state_lock); |
177 | if (!new_transaction) | |
470decc6 | 178 | goto alloc_transaction; |
a931da6a TT |
179 | write_lock(&journal->j_state_lock); |
180 | if (!journal->j_running_transaction) { | |
181 | jbd2_get_transaction(journal, new_transaction); | |
182 | new_transaction = NULL; | |
470decc6 | 183 | } |
a931da6a TT |
184 | write_unlock(&journal->j_state_lock); |
185 | goto repeat; | |
470decc6 DK |
186 | } |
187 | ||
188 | transaction = journal->j_running_transaction; | |
189 | ||
190 | /* | |
191 | * If the current transaction is locked down for commit, wait for the | |
192 | * lock to be released. | |
193 | */ | |
194 | if (transaction->t_state == T_LOCKED) { | |
195 | DEFINE_WAIT(wait); | |
196 | ||
197 | prepare_to_wait(&journal->j_wait_transaction_locked, | |
198 | &wait, TASK_UNINTERRUPTIBLE); | |
a931da6a | 199 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
200 | schedule(); |
201 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
202 | goto repeat; | |
203 | } | |
204 | ||
205 | /* | |
206 | * If there is not enough space left in the log to write all potential | |
207 | * buffers requested by this operation, we need to stall pending a log | |
208 | * checkpoint to free some more log space. | |
209 | */ | |
8dd42046 TT |
210 | needed = atomic_add_return(nblocks, |
211 | &transaction->t_outstanding_credits); | |
470decc6 DK |
212 | |
213 | if (needed > journal->j_max_transaction_buffers) { | |
214 | /* | |
215 | * If the current transaction is already too large, then start | |
216 | * to commit it: we can then go back and attach this handle to | |
217 | * a new transaction. | |
218 | */ | |
219 | DEFINE_WAIT(wait); | |
220 | ||
221 | jbd_debug(2, "Handle %p starting new commit...\n", handle); | |
8dd42046 | 222 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
223 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, |
224 | TASK_UNINTERRUPTIBLE); | |
f7f4bccb | 225 | __jbd2_log_start_commit(journal, transaction->t_tid); |
a931da6a | 226 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
227 | schedule(); |
228 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
229 | goto repeat; | |
230 | } | |
231 | ||
232 | /* | |
233 | * The commit code assumes that it can get enough log space | |
234 | * without forcing a checkpoint. This is *critical* for | |
235 | * correctness: a checkpoint of a buffer which is also | |
236 | * associated with a committing transaction creates a deadlock, | |
237 | * so commit simply cannot force through checkpoints. | |
238 | * | |
239 | * We must therefore ensure the necessary space in the journal | |
240 | * *before* starting to dirty potentially checkpointed buffers | |
241 | * in the new transaction. | |
242 | * | |
243 | * The worst part is, any transaction currently committing can | |
244 | * reduce the free space arbitrarily. Be careful to account for | |
245 | * those buffers when checkpointing. | |
246 | */ | |
247 | ||
248 | /* | |
249 | * @@@ AKPM: This seems rather over-defensive. We're giving commit | |
250 | * a _lot_ of headroom: 1/4 of the journal plus the size of | |
251 | * the committing transaction. Really, we only need to give it | |
252 | * committing_transaction->t_outstanding_credits plus "enough" for | |
253 | * the log control blocks. | |
a34f0b31 | 254 | * Also, this test is inconsistent with the matching one in |
f7f4bccb | 255 | * jbd2_journal_extend(). |
470decc6 | 256 | */ |
f7f4bccb | 257 | if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) { |
470decc6 | 258 | jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle); |
8dd42046 | 259 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
a931da6a TT |
260 | read_unlock(&journal->j_state_lock); |
261 | write_lock(&journal->j_state_lock); | |
262 | if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) | |
263 | __jbd2_log_wait_for_space(journal); | |
264 | write_unlock(&journal->j_state_lock); | |
265 | goto repeat; | |
470decc6 DK |
266 | } |
267 | ||
268 | /* OK, account for the buffers that this operation expects to | |
8dd42046 | 269 | * use and add the handle to the running transaction. |
8dd42046 | 270 | */ |
6d0bf005 | 271 | update_t_max_wait(transaction); |
470decc6 | 272 | handle->h_transaction = transaction; |
a51dca9c | 273 | atomic_inc(&transaction->t_updates); |
8dd42046 | 274 | atomic_inc(&transaction->t_handle_count); |
470decc6 | 275 | jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n", |
a51dca9c TT |
276 | handle, nblocks, |
277 | atomic_read(&transaction->t_outstanding_credits), | |
f7f4bccb | 278 | __jbd2_log_space_left(journal)); |
a931da6a | 279 | read_unlock(&journal->j_state_lock); |
9599b0e5 JK |
280 | |
281 | lock_map_acquire(&handle->h_lockdep_map); | |
47def826 TT |
282 | kfree(new_transaction); |
283 | return 0; | |
470decc6 DK |
284 | } |
285 | ||
7b751066 MC |
286 | static struct lock_class_key jbd2_handle_key; |
287 | ||
470decc6 DK |
288 | /* Allocate a new handle. This should probably be in a slab... */ |
289 | static handle_t *new_handle(int nblocks) | |
290 | { | |
af1e76d6 | 291 | handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
470decc6 DK |
292 | if (!handle) |
293 | return NULL; | |
294 | memset(handle, 0, sizeof(*handle)); | |
295 | handle->h_buffer_credits = nblocks; | |
296 | handle->h_ref = 1; | |
297 | ||
7b751066 MC |
298 | lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle", |
299 | &jbd2_handle_key, 0); | |
300 | ||
470decc6 DK |
301 | return handle; |
302 | } | |
303 | ||
304 | /** | |
f7f4bccb | 305 | * handle_t *jbd2_journal_start() - Obtain a new handle. |
470decc6 DK |
306 | * @journal: Journal to start transaction on. |
307 | * @nblocks: number of block buffer we might modify | |
308 | * | |
309 | * We make sure that the transaction can guarantee at least nblocks of | |
310 | * modified buffers in the log. We block until the log can guarantee | |
311 | * that much space. | |
312 | * | |
313 | * This function is visible to journal users (like ext3fs), so is not | |
314 | * called with the journal already locked. | |
315 | * | |
316 | * Return a pointer to a newly allocated handle, or NULL on failure | |
317 | */ | |
47def826 | 318 | handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int gfp_mask) |
470decc6 DK |
319 | { |
320 | handle_t *handle = journal_current_handle(); | |
321 | int err; | |
322 | ||
323 | if (!journal) | |
324 | return ERR_PTR(-EROFS); | |
325 | ||
326 | if (handle) { | |
327 | J_ASSERT(handle->h_transaction->t_journal == journal); | |
328 | handle->h_ref++; | |
329 | return handle; | |
330 | } | |
331 | ||
332 | handle = new_handle(nblocks); | |
333 | if (!handle) | |
334 | return ERR_PTR(-ENOMEM); | |
335 | ||
336 | current->journal_info = handle; | |
337 | ||
47def826 | 338 | err = start_this_handle(journal, handle, gfp_mask); |
470decc6 | 339 | if (err < 0) { |
af1e76d6 | 340 | jbd2_free_handle(handle); |
470decc6 DK |
341 | current->journal_info = NULL; |
342 | handle = ERR_PTR(err); | |
343 | } | |
344 | return handle; | |
345 | } | |
47def826 TT |
346 | EXPORT_SYMBOL(jbd2__journal_start); |
347 | ||
348 | ||
349 | handle_t *jbd2_journal_start(journal_t *journal, int nblocks) | |
350 | { | |
351 | return jbd2__journal_start(journal, nblocks, GFP_NOFS); | |
352 | } | |
353 | EXPORT_SYMBOL(jbd2_journal_start); | |
354 | ||
470decc6 DK |
355 | |
356 | /** | |
f7f4bccb | 357 | * int jbd2_journal_extend() - extend buffer credits. |
470decc6 DK |
358 | * @handle: handle to 'extend' |
359 | * @nblocks: nr blocks to try to extend by. | |
360 | * | |
361 | * Some transactions, such as large extends and truncates, can be done | |
362 | * atomically all at once or in several stages. The operation requests | |
363 | * a credit for a number of buffer modications in advance, but can | |
364 | * extend its credit if it needs more. | |
365 | * | |
f7f4bccb | 366 | * jbd2_journal_extend tries to give the running handle more buffer credits. |
470decc6 DK |
367 | * It does not guarantee that allocation - this is a best-effort only. |
368 | * The calling process MUST be able to deal cleanly with a failure to | |
369 | * extend here. | |
370 | * | |
371 | * Return 0 on success, non-zero on failure. | |
372 | * | |
373 | * return code < 0 implies an error | |
374 | * return code > 0 implies normal transaction-full status. | |
375 | */ | |
f7f4bccb | 376 | int jbd2_journal_extend(handle_t *handle, int nblocks) |
470decc6 DK |
377 | { |
378 | transaction_t *transaction = handle->h_transaction; | |
379 | journal_t *journal = transaction->t_journal; | |
380 | int result; | |
381 | int wanted; | |
382 | ||
383 | result = -EIO; | |
384 | if (is_handle_aborted(handle)) | |
385 | goto out; | |
386 | ||
387 | result = 1; | |
388 | ||
a931da6a | 389 | read_lock(&journal->j_state_lock); |
470decc6 DK |
390 | |
391 | /* Don't extend a locked-down transaction! */ | |
392 | if (handle->h_transaction->t_state != T_RUNNING) { | |
393 | jbd_debug(3, "denied handle %p %d blocks: " | |
394 | "transaction not running\n", handle, nblocks); | |
395 | goto error_out; | |
396 | } | |
397 | ||
398 | spin_lock(&transaction->t_handle_lock); | |
a51dca9c | 399 | wanted = atomic_read(&transaction->t_outstanding_credits) + nblocks; |
470decc6 DK |
400 | |
401 | if (wanted > journal->j_max_transaction_buffers) { | |
402 | jbd_debug(3, "denied handle %p %d blocks: " | |
403 | "transaction too large\n", handle, nblocks); | |
404 | goto unlock; | |
405 | } | |
406 | ||
f7f4bccb | 407 | if (wanted > __jbd2_log_space_left(journal)) { |
470decc6 DK |
408 | jbd_debug(3, "denied handle %p %d blocks: " |
409 | "insufficient log space\n", handle, nblocks); | |
410 | goto unlock; | |
411 | } | |
412 | ||
413 | handle->h_buffer_credits += nblocks; | |
a51dca9c | 414 | atomic_add(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
415 | result = 0; |
416 | ||
417 | jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); | |
418 | unlock: | |
419 | spin_unlock(&transaction->t_handle_lock); | |
420 | error_out: | |
a931da6a | 421 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
422 | out: |
423 | return result; | |
424 | } | |
425 | ||
426 | ||
427 | /** | |
f7f4bccb | 428 | * int jbd2_journal_restart() - restart a handle . |
470decc6 DK |
429 | * @handle: handle to restart |
430 | * @nblocks: nr credits requested | |
431 | * | |
432 | * Restart a handle for a multi-transaction filesystem | |
433 | * operation. | |
434 | * | |
f7f4bccb MC |
435 | * If the jbd2_journal_extend() call above fails to grant new buffer credits |
436 | * to a running handle, a call to jbd2_journal_restart will commit the | |
470decc6 DK |
437 | * handle's transaction so far and reattach the handle to a new |
438 | * transaction capabable of guaranteeing the requested number of | |
439 | * credits. | |
440 | */ | |
47def826 | 441 | int jbd2__journal_restart(handle_t *handle, int nblocks, int gfp_mask) |
470decc6 DK |
442 | { |
443 | transaction_t *transaction = handle->h_transaction; | |
444 | journal_t *journal = transaction->t_journal; | |
445 | int ret; | |
446 | ||
447 | /* If we've had an abort of any type, don't even think about | |
448 | * actually doing the restart! */ | |
449 | if (is_handle_aborted(handle)) | |
450 | return 0; | |
451 | ||
452 | /* | |
453 | * First unlink the handle from its current transaction, and start the | |
454 | * commit on that. | |
455 | */ | |
a51dca9c | 456 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 DK |
457 | J_ASSERT(journal_current_handle() == handle); |
458 | ||
a931da6a | 459 | read_lock(&journal->j_state_lock); |
470decc6 | 460 | spin_lock(&transaction->t_handle_lock); |
a51dca9c TT |
461 | atomic_sub(handle->h_buffer_credits, |
462 | &transaction->t_outstanding_credits); | |
463 | if (atomic_dec_and_test(&transaction->t_updates)) | |
470decc6 DK |
464 | wake_up(&journal->j_wait_updates); |
465 | spin_unlock(&transaction->t_handle_lock); | |
466 | ||
467 | jbd_debug(2, "restarting handle %p\n", handle); | |
f7f4bccb | 468 | __jbd2_log_start_commit(journal, transaction->t_tid); |
a931da6a | 469 | read_unlock(&journal->j_state_lock); |
470decc6 | 470 | |
9599b0e5 | 471 | lock_map_release(&handle->h_lockdep_map); |
470decc6 | 472 | handle->h_buffer_credits = nblocks; |
47def826 | 473 | ret = start_this_handle(journal, handle, gfp_mask); |
470decc6 DK |
474 | return ret; |
475 | } | |
47def826 | 476 | EXPORT_SYMBOL(jbd2__journal_restart); |
470decc6 DK |
477 | |
478 | ||
47def826 TT |
479 | int jbd2_journal_restart(handle_t *handle, int nblocks) |
480 | { | |
481 | return jbd2__journal_restart(handle, nblocks, GFP_NOFS); | |
482 | } | |
483 | EXPORT_SYMBOL(jbd2_journal_restart); | |
484 | ||
470decc6 | 485 | /** |
f7f4bccb | 486 | * void jbd2_journal_lock_updates () - establish a transaction barrier. |
470decc6 DK |
487 | * @journal: Journal to establish a barrier on. |
488 | * | |
489 | * This locks out any further updates from being started, and blocks | |
490 | * until all existing updates have completed, returning only once the | |
491 | * journal is in a quiescent state with no updates running. | |
492 | * | |
493 | * The journal lock should not be held on entry. | |
494 | */ | |
f7f4bccb | 495 | void jbd2_journal_lock_updates(journal_t *journal) |
470decc6 DK |
496 | { |
497 | DEFINE_WAIT(wait); | |
498 | ||
a931da6a | 499 | write_lock(&journal->j_state_lock); |
470decc6 DK |
500 | ++journal->j_barrier_count; |
501 | ||
502 | /* Wait until there are no running updates */ | |
503 | while (1) { | |
504 | transaction_t *transaction = journal->j_running_transaction; | |
505 | ||
506 | if (!transaction) | |
507 | break; | |
508 | ||
509 | spin_lock(&transaction->t_handle_lock); | |
a51dca9c | 510 | if (!atomic_read(&transaction->t_updates)) { |
470decc6 DK |
511 | spin_unlock(&transaction->t_handle_lock); |
512 | break; | |
513 | } | |
514 | prepare_to_wait(&journal->j_wait_updates, &wait, | |
515 | TASK_UNINTERRUPTIBLE); | |
516 | spin_unlock(&transaction->t_handle_lock); | |
a931da6a | 517 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
518 | schedule(); |
519 | finish_wait(&journal->j_wait_updates, &wait); | |
a931da6a | 520 | write_lock(&journal->j_state_lock); |
470decc6 | 521 | } |
a931da6a | 522 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
523 | |
524 | /* | |
525 | * We have now established a barrier against other normal updates, but | |
f7f4bccb | 526 | * we also need to barrier against other jbd2_journal_lock_updates() calls |
470decc6 DK |
527 | * to make sure that we serialise special journal-locked operations |
528 | * too. | |
529 | */ | |
530 | mutex_lock(&journal->j_barrier); | |
531 | } | |
532 | ||
533 | /** | |
f7f4bccb | 534 | * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier |
470decc6 DK |
535 | * @journal: Journal to release the barrier on. |
536 | * | |
f7f4bccb | 537 | * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
470decc6 DK |
538 | * |
539 | * Should be called without the journal lock held. | |
540 | */ | |
f7f4bccb | 541 | void jbd2_journal_unlock_updates (journal_t *journal) |
470decc6 DK |
542 | { |
543 | J_ASSERT(journal->j_barrier_count != 0); | |
544 | ||
545 | mutex_unlock(&journal->j_barrier); | |
a931da6a | 546 | write_lock(&journal->j_state_lock); |
470decc6 | 547 | --journal->j_barrier_count; |
a931da6a | 548 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
549 | wake_up(&journal->j_wait_transaction_locked); |
550 | } | |
551 | ||
f91d1d04 | 552 | static void warn_dirty_buffer(struct buffer_head *bh) |
470decc6 | 553 | { |
f91d1d04 | 554 | char b[BDEVNAME_SIZE]; |
470decc6 | 555 | |
f91d1d04 JK |
556 | printk(KERN_WARNING |
557 | "JBD: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). " | |
558 | "There's a risk of filesystem corruption in case of system " | |
559 | "crash.\n", | |
560 | bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr); | |
470decc6 DK |
561 | } |
562 | ||
563 | /* | |
564 | * If the buffer is already part of the current transaction, then there | |
565 | * is nothing we need to do. If it is already part of a prior | |
566 | * transaction which we are still committing to disk, then we need to | |
567 | * make sure that we do not overwrite the old copy: we do copy-out to | |
568 | * preserve the copy going to disk. We also account the buffer against | |
569 | * the handle's metadata buffer credits (unless the buffer is already | |
570 | * part of the transaction, that is). | |
571 | * | |
572 | */ | |
573 | static int | |
574 | do_get_write_access(handle_t *handle, struct journal_head *jh, | |
575 | int force_copy) | |
576 | { | |
577 | struct buffer_head *bh; | |
578 | transaction_t *transaction; | |
579 | journal_t *journal; | |
580 | int error; | |
581 | char *frozen_buffer = NULL; | |
582 | int need_copy = 0; | |
583 | ||
584 | if (is_handle_aborted(handle)) | |
585 | return -EROFS; | |
586 | ||
587 | transaction = handle->h_transaction; | |
588 | journal = transaction->t_journal; | |
589 | ||
cfef2c6a | 590 | jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy); |
470decc6 DK |
591 | |
592 | JBUFFER_TRACE(jh, "entry"); | |
593 | repeat: | |
594 | bh = jh2bh(jh); | |
595 | ||
596 | /* @@@ Need to check for errors here at some point. */ | |
597 | ||
598 | lock_buffer(bh); | |
599 | jbd_lock_bh_state(bh); | |
600 | ||
601 | /* We now hold the buffer lock so it is safe to query the buffer | |
602 | * state. Is the buffer dirty? | |
603 | * | |
604 | * If so, there are two possibilities. The buffer may be | |
605 | * non-journaled, and undergoing a quite legitimate writeback. | |
606 | * Otherwise, it is journaled, and we don't expect dirty buffers | |
607 | * in that state (the buffers should be marked JBD_Dirty | |
608 | * instead.) So either the IO is being done under our own | |
609 | * control and this is a bug, or it's a third party IO such as | |
610 | * dump(8) (which may leave the buffer scheduled for read --- | |
611 | * ie. locked but not dirty) or tune2fs (which may actually have | |
612 | * the buffer dirtied, ugh.) */ | |
613 | ||
614 | if (buffer_dirty(bh)) { | |
615 | /* | |
616 | * First question: is this buffer already part of the current | |
617 | * transaction or the existing committing transaction? | |
618 | */ | |
619 | if (jh->b_transaction) { | |
620 | J_ASSERT_JH(jh, | |
621 | jh->b_transaction == transaction || | |
622 | jh->b_transaction == | |
623 | journal->j_committing_transaction); | |
624 | if (jh->b_next_transaction) | |
625 | J_ASSERT_JH(jh, jh->b_next_transaction == | |
626 | transaction); | |
f91d1d04 | 627 | warn_dirty_buffer(bh); |
470decc6 DK |
628 | } |
629 | /* | |
630 | * In any case we need to clean the dirty flag and we must | |
631 | * do it under the buffer lock to be sure we don't race | |
632 | * with running write-out. | |
633 | */ | |
f91d1d04 JK |
634 | JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
635 | clear_buffer_dirty(bh); | |
636 | set_buffer_jbddirty(bh); | |
470decc6 DK |
637 | } |
638 | ||
639 | unlock_buffer(bh); | |
640 | ||
641 | error = -EROFS; | |
642 | if (is_handle_aborted(handle)) { | |
643 | jbd_unlock_bh_state(bh); | |
644 | goto out; | |
645 | } | |
646 | error = 0; | |
647 | ||
648 | /* | |
649 | * The buffer is already part of this transaction if b_transaction or | |
650 | * b_next_transaction points to it | |
651 | */ | |
652 | if (jh->b_transaction == transaction || | |
653 | jh->b_next_transaction == transaction) | |
654 | goto done; | |
655 | ||
9fc7c63a JB |
656 | /* |
657 | * this is the first time this transaction is touching this buffer, | |
658 | * reset the modified flag | |
659 | */ | |
660 | jh->b_modified = 0; | |
661 | ||
470decc6 DK |
662 | /* |
663 | * If there is already a copy-out version of this buffer, then we don't | |
664 | * need to make another one | |
665 | */ | |
666 | if (jh->b_frozen_data) { | |
667 | JBUFFER_TRACE(jh, "has frozen data"); | |
668 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
669 | jh->b_next_transaction = transaction; | |
670 | goto done; | |
671 | } | |
672 | ||
673 | /* Is there data here we need to preserve? */ | |
674 | ||
675 | if (jh->b_transaction && jh->b_transaction != transaction) { | |
676 | JBUFFER_TRACE(jh, "owned by older transaction"); | |
677 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
678 | J_ASSERT_JH(jh, jh->b_transaction == | |
679 | journal->j_committing_transaction); | |
680 | ||
681 | /* There is one case we have to be very careful about. | |
682 | * If the committing transaction is currently writing | |
683 | * this buffer out to disk and has NOT made a copy-out, | |
684 | * then we cannot modify the buffer contents at all | |
685 | * right now. The essence of copy-out is that it is the | |
686 | * extra copy, not the primary copy, which gets | |
687 | * journaled. If the primary copy is already going to | |
688 | * disk then we cannot do copy-out here. */ | |
689 | ||
690 | if (jh->b_jlist == BJ_Shadow) { | |
691 | DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow); | |
692 | wait_queue_head_t *wqh; | |
693 | ||
694 | wqh = bit_waitqueue(&bh->b_state, BH_Unshadow); | |
695 | ||
696 | JBUFFER_TRACE(jh, "on shadow: sleep"); | |
697 | jbd_unlock_bh_state(bh); | |
698 | /* commit wakes up all shadow buffers after IO */ | |
699 | for ( ; ; ) { | |
700 | prepare_to_wait(wqh, &wait.wait, | |
701 | TASK_UNINTERRUPTIBLE); | |
702 | if (jh->b_jlist != BJ_Shadow) | |
703 | break; | |
704 | schedule(); | |
705 | } | |
706 | finish_wait(wqh, &wait.wait); | |
707 | goto repeat; | |
708 | } | |
709 | ||
710 | /* Only do the copy if the currently-owning transaction | |
711 | * still needs it. If it is on the Forget list, the | |
712 | * committing transaction is past that stage. The | |
713 | * buffer had better remain locked during the kmalloc, | |
714 | * but that should be true --- we hold the journal lock | |
715 | * still and the buffer is already on the BUF_JOURNAL | |
716 | * list so won't be flushed. | |
717 | * | |
718 | * Subtle point, though: if this is a get_undo_access, | |
719 | * then we will be relying on the frozen_data to contain | |
720 | * the new value of the committed_data record after the | |
721 | * transaction, so we HAVE to force the frozen_data copy | |
722 | * in that case. */ | |
723 | ||
724 | if (jh->b_jlist != BJ_Forget || force_copy) { | |
725 | JBUFFER_TRACE(jh, "generate frozen data"); | |
726 | if (!frozen_buffer) { | |
727 | JBUFFER_TRACE(jh, "allocate memory for buffer"); | |
728 | jbd_unlock_bh_state(bh); | |
729 | frozen_buffer = | |
af1e76d6 | 730 | jbd2_alloc(jh2bh(jh)->b_size, |
470decc6 DK |
731 | GFP_NOFS); |
732 | if (!frozen_buffer) { | |
733 | printk(KERN_EMERG | |
734 | "%s: OOM for frozen_buffer\n", | |
329d291f | 735 | __func__); |
470decc6 DK |
736 | JBUFFER_TRACE(jh, "oom!"); |
737 | error = -ENOMEM; | |
738 | jbd_lock_bh_state(bh); | |
739 | goto done; | |
740 | } | |
741 | goto repeat; | |
742 | } | |
743 | jh->b_frozen_data = frozen_buffer; | |
744 | frozen_buffer = NULL; | |
745 | need_copy = 1; | |
746 | } | |
747 | jh->b_next_transaction = transaction; | |
748 | } | |
749 | ||
750 | ||
751 | /* | |
752 | * Finally, if the buffer is not journaled right now, we need to make | |
753 | * sure it doesn't get written to disk before the caller actually | |
754 | * commits the new data | |
755 | */ | |
756 | if (!jh->b_transaction) { | |
757 | JBUFFER_TRACE(jh, "no transaction"); | |
758 | J_ASSERT_JH(jh, !jh->b_next_transaction); | |
759 | jh->b_transaction = transaction; | |
760 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); | |
761 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 762 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 DK |
763 | spin_unlock(&journal->j_list_lock); |
764 | } | |
765 | ||
766 | done: | |
767 | if (need_copy) { | |
768 | struct page *page; | |
769 | int offset; | |
770 | char *source; | |
771 | ||
772 | J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)), | |
773 | "Possible IO failure.\n"); | |
774 | page = jh2bh(jh)->b_page; | |
a1dd5331 | 775 | offset = offset_in_page(jh2bh(jh)->b_data); |
470decc6 | 776 | source = kmap_atomic(page, KM_USER0); |
13ceef09 JK |
777 | /* Fire data frozen trigger just before we copy the data */ |
778 | jbd2_buffer_frozen_trigger(jh, source + offset, | |
779 | jh->b_triggers); | |
470decc6 DK |
780 | memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size); |
781 | kunmap_atomic(source, KM_USER0); | |
e06c8227 JB |
782 | |
783 | /* | |
784 | * Now that the frozen data is saved off, we need to store | |
785 | * any matching triggers. | |
786 | */ | |
787 | jh->b_frozen_triggers = jh->b_triggers; | |
470decc6 DK |
788 | } |
789 | jbd_unlock_bh_state(bh); | |
790 | ||
791 | /* | |
792 | * If we are about to journal a buffer, then any revoke pending on it is | |
793 | * no longer valid | |
794 | */ | |
f7f4bccb | 795 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 DK |
796 | |
797 | out: | |
798 | if (unlikely(frozen_buffer)) /* It's usually NULL */ | |
af1e76d6 | 799 | jbd2_free(frozen_buffer, bh->b_size); |
470decc6 DK |
800 | |
801 | JBUFFER_TRACE(jh, "exit"); | |
802 | return error; | |
803 | } | |
804 | ||
805 | /** | |
f7f4bccb | 806 | * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update. |
470decc6 DK |
807 | * @handle: transaction to add buffer modifications to |
808 | * @bh: bh to be used for metadata writes | |
809 | * @credits: variable that will receive credits for the buffer | |
810 | * | |
811 | * Returns an error code or 0 on success. | |
812 | * | |
813 | * In full data journalling mode the buffer may be of type BJ_AsyncData, | |
814 | * because we're write()ing a buffer which is also part of a shared mapping. | |
815 | */ | |
816 | ||
f7f4bccb | 817 | int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
470decc6 | 818 | { |
f7f4bccb | 819 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
820 | int rc; |
821 | ||
822 | /* We do not want to get caught playing with fields which the | |
823 | * log thread also manipulates. Make sure that the buffer | |
824 | * completes any outstanding IO before proceeding. */ | |
825 | rc = do_get_write_access(handle, jh, 0); | |
f7f4bccb | 826 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
827 | return rc; |
828 | } | |
829 | ||
830 | ||
831 | /* | |
832 | * When the user wants to journal a newly created buffer_head | |
833 | * (ie. getblk() returned a new buffer and we are going to populate it | |
834 | * manually rather than reading off disk), then we need to keep the | |
835 | * buffer_head locked until it has been completely filled with new | |
836 | * data. In this case, we should be able to make the assertion that | |
837 | * the bh is not already part of an existing transaction. | |
838 | * | |
839 | * The buffer should already be locked by the caller by this point. | |
840 | * There is no lock ranking violation: it was a newly created, | |
841 | * unlocked buffer beforehand. */ | |
842 | ||
843 | /** | |
f7f4bccb | 844 | * int jbd2_journal_get_create_access () - notify intent to use newly created bh |
470decc6 DK |
845 | * @handle: transaction to new buffer to |
846 | * @bh: new buffer. | |
847 | * | |
848 | * Call this if you create a new bh. | |
849 | */ | |
f7f4bccb | 850 | int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
851 | { |
852 | transaction_t *transaction = handle->h_transaction; | |
853 | journal_t *journal = transaction->t_journal; | |
f7f4bccb | 854 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
855 | int err; |
856 | ||
857 | jbd_debug(5, "journal_head %p\n", jh); | |
858 | err = -EROFS; | |
859 | if (is_handle_aborted(handle)) | |
860 | goto out; | |
861 | err = 0; | |
862 | ||
863 | JBUFFER_TRACE(jh, "entry"); | |
864 | /* | |
865 | * The buffer may already belong to this transaction due to pre-zeroing | |
866 | * in the filesystem's new_block code. It may also be on the previous, | |
867 | * committing transaction's lists, but it HAS to be in Forget state in | |
868 | * that case: the transaction must have deleted the buffer for it to be | |
869 | * reused here. | |
870 | */ | |
871 | jbd_lock_bh_state(bh); | |
872 | spin_lock(&journal->j_list_lock); | |
873 | J_ASSERT_JH(jh, (jh->b_transaction == transaction || | |
874 | jh->b_transaction == NULL || | |
875 | (jh->b_transaction == journal->j_committing_transaction && | |
876 | jh->b_jlist == BJ_Forget))); | |
877 | ||
878 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
879 | J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); | |
880 | ||
881 | if (jh->b_transaction == NULL) { | |
f91d1d04 JK |
882 | /* |
883 | * Previous jbd2_journal_forget() could have left the buffer | |
884 | * with jbddirty bit set because it was being committed. When | |
885 | * the commit finished, we've filed the buffer for | |
886 | * checkpointing and marked it dirty. Now we are reallocating | |
887 | * the buffer so the transaction freeing it must have | |
888 | * committed and so it's safe to clear the dirty bit. | |
889 | */ | |
890 | clear_buffer_dirty(jh2bh(jh)); | |
470decc6 | 891 | jh->b_transaction = transaction; |
9fc7c63a JB |
892 | |
893 | /* first access by this transaction */ | |
894 | jh->b_modified = 0; | |
895 | ||
470decc6 | 896 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
f7f4bccb | 897 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 | 898 | } else if (jh->b_transaction == journal->j_committing_transaction) { |
9fc7c63a JB |
899 | /* first access by this transaction */ |
900 | jh->b_modified = 0; | |
901 | ||
470decc6 DK |
902 | JBUFFER_TRACE(jh, "set next transaction"); |
903 | jh->b_next_transaction = transaction; | |
904 | } | |
905 | spin_unlock(&journal->j_list_lock); | |
906 | jbd_unlock_bh_state(bh); | |
907 | ||
908 | /* | |
909 | * akpm: I added this. ext3_alloc_branch can pick up new indirect | |
910 | * blocks which contain freed but then revoked metadata. We need | |
911 | * to cancel the revoke in case we end up freeing it yet again | |
912 | * and the reallocating as data - this would cause a second revoke, | |
913 | * which hits an assertion error. | |
914 | */ | |
915 | JBUFFER_TRACE(jh, "cancelling revoke"); | |
f7f4bccb MC |
916 | jbd2_journal_cancel_revoke(handle, jh); |
917 | jbd2_journal_put_journal_head(jh); | |
470decc6 DK |
918 | out: |
919 | return err; | |
920 | } | |
921 | ||
922 | /** | |
f7f4bccb | 923 | * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
470decc6 DK |
924 | * non-rewindable consequences |
925 | * @handle: transaction | |
926 | * @bh: buffer to undo | |
927 | * @credits: store the number of taken credits here (if not NULL) | |
928 | * | |
929 | * Sometimes there is a need to distinguish between metadata which has | |
930 | * been committed to disk and that which has not. The ext3fs code uses | |
931 | * this for freeing and allocating space, we have to make sure that we | |
932 | * do not reuse freed space until the deallocation has been committed, | |
933 | * since if we overwrote that space we would make the delete | |
934 | * un-rewindable in case of a crash. | |
935 | * | |
f7f4bccb | 936 | * To deal with that, jbd2_journal_get_undo_access requests write access to a |
470decc6 DK |
937 | * buffer for parts of non-rewindable operations such as delete |
938 | * operations on the bitmaps. The journaling code must keep a copy of | |
939 | * the buffer's contents prior to the undo_access call until such time | |
940 | * as we know that the buffer has definitely been committed to disk. | |
941 | * | |
942 | * We never need to know which transaction the committed data is part | |
943 | * of, buffers touched here are guaranteed to be dirtied later and so | |
944 | * will be committed to a new transaction in due course, at which point | |
945 | * we can discard the old committed data pointer. | |
946 | * | |
947 | * Returns error number or 0 on success. | |
948 | */ | |
f7f4bccb | 949 | int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
950 | { |
951 | int err; | |
f7f4bccb | 952 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
953 | char *committed_data = NULL; |
954 | ||
955 | JBUFFER_TRACE(jh, "entry"); | |
956 | ||
957 | /* | |
958 | * Do this first --- it can drop the journal lock, so we want to | |
959 | * make sure that obtaining the committed_data is done | |
960 | * atomically wrt. completion of any outstanding commits. | |
961 | */ | |
962 | err = do_get_write_access(handle, jh, 1); | |
963 | if (err) | |
964 | goto out; | |
965 | ||
966 | repeat: | |
967 | if (!jh->b_committed_data) { | |
af1e76d6 | 968 | committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); |
470decc6 DK |
969 | if (!committed_data) { |
970 | printk(KERN_EMERG "%s: No memory for committed data\n", | |
329d291f | 971 | __func__); |
470decc6 DK |
972 | err = -ENOMEM; |
973 | goto out; | |
974 | } | |
975 | } | |
976 | ||
977 | jbd_lock_bh_state(bh); | |
978 | if (!jh->b_committed_data) { | |
979 | /* Copy out the current buffer contents into the | |
980 | * preserved, committed copy. */ | |
981 | JBUFFER_TRACE(jh, "generate b_committed data"); | |
982 | if (!committed_data) { | |
983 | jbd_unlock_bh_state(bh); | |
984 | goto repeat; | |
985 | } | |
986 | ||
987 | jh->b_committed_data = committed_data; | |
988 | committed_data = NULL; | |
989 | memcpy(jh->b_committed_data, bh->b_data, bh->b_size); | |
990 | } | |
991 | jbd_unlock_bh_state(bh); | |
992 | out: | |
f7f4bccb | 993 | jbd2_journal_put_journal_head(jh); |
470decc6 | 994 | if (unlikely(committed_data)) |
af1e76d6 | 995 | jbd2_free(committed_data, bh->b_size); |
470decc6 DK |
996 | return err; |
997 | } | |
998 | ||
e06c8227 JB |
999 | /** |
1000 | * void jbd2_journal_set_triggers() - Add triggers for commit writeout | |
1001 | * @bh: buffer to trigger on | |
1002 | * @type: struct jbd2_buffer_trigger_type containing the trigger(s). | |
1003 | * | |
1004 | * Set any triggers on this journal_head. This is always safe, because | |
1005 | * triggers for a committing buffer will be saved off, and triggers for | |
1006 | * a running transaction will match the buffer in that transaction. | |
1007 | * | |
1008 | * Call with NULL to clear the triggers. | |
1009 | */ | |
1010 | void jbd2_journal_set_triggers(struct buffer_head *bh, | |
1011 | struct jbd2_buffer_trigger_type *type) | |
1012 | { | |
1013 | struct journal_head *jh = bh2jh(bh); | |
1014 | ||
1015 | jh->b_triggers = type; | |
1016 | } | |
1017 | ||
13ceef09 | 1018 | void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data, |
e06c8227 JB |
1019 | struct jbd2_buffer_trigger_type *triggers) |
1020 | { | |
1021 | struct buffer_head *bh = jh2bh(jh); | |
1022 | ||
13ceef09 | 1023 | if (!triggers || !triggers->t_frozen) |
e06c8227 JB |
1024 | return; |
1025 | ||
13ceef09 | 1026 | triggers->t_frozen(triggers, bh, mapped_data, bh->b_size); |
e06c8227 JB |
1027 | } |
1028 | ||
1029 | void jbd2_buffer_abort_trigger(struct journal_head *jh, | |
1030 | struct jbd2_buffer_trigger_type *triggers) | |
1031 | { | |
1032 | if (!triggers || !triggers->t_abort) | |
1033 | return; | |
1034 | ||
1035 | triggers->t_abort(triggers, jh2bh(jh)); | |
1036 | } | |
1037 | ||
1038 | ||
1039 | ||
470decc6 | 1040 | /** |
f7f4bccb | 1041 | * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
470decc6 DK |
1042 | * @handle: transaction to add buffer to. |
1043 | * @bh: buffer to mark | |
1044 | * | |
1045 | * mark dirty metadata which needs to be journaled as part of the current | |
1046 | * transaction. | |
1047 | * | |
1048 | * The buffer is placed on the transaction's metadata list and is marked | |
1049 | * as belonging to the transaction. | |
1050 | * | |
1051 | * Returns error number or 0 on success. | |
1052 | * | |
1053 | * Special care needs to be taken if the buffer already belongs to the | |
1054 | * current committing transaction (in which case we should have frozen | |
1055 | * data present for that commit). In that case, we don't relink the | |
1056 | * buffer: that only gets done when the old transaction finally | |
1057 | * completes its commit. | |
1058 | */ | |
f7f4bccb | 1059 | int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1060 | { |
1061 | transaction_t *transaction = handle->h_transaction; | |
1062 | journal_t *journal = transaction->t_journal; | |
1063 | struct journal_head *jh = bh2jh(bh); | |
1064 | ||
1065 | jbd_debug(5, "journal_head %p\n", jh); | |
1066 | JBUFFER_TRACE(jh, "entry"); | |
1067 | if (is_handle_aborted(handle)) | |
1068 | goto out; | |
1069 | ||
1070 | jbd_lock_bh_state(bh); | |
1071 | ||
1072 | if (jh->b_modified == 0) { | |
1073 | /* | |
1074 | * This buffer's got modified and becoming part | |
1075 | * of the transaction. This needs to be done | |
1076 | * once a transaction -bzzz | |
1077 | */ | |
1078 | jh->b_modified = 1; | |
1079 | J_ASSERT_JH(jh, handle->h_buffer_credits > 0); | |
1080 | handle->h_buffer_credits--; | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * fastpath, to avoid expensive locking. If this buffer is already | |
1085 | * on the running transaction's metadata list there is nothing to do. | |
1086 | * Nobody can take it off again because there is a handle open. | |
1087 | * I _think_ we're OK here with SMP barriers - a mistaken decision will | |
1088 | * result in this test being false, so we go in and take the locks. | |
1089 | */ | |
1090 | if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { | |
1091 | JBUFFER_TRACE(jh, "fastpath"); | |
1092 | J_ASSERT_JH(jh, jh->b_transaction == | |
1093 | journal->j_running_transaction); | |
1094 | goto out_unlock_bh; | |
1095 | } | |
1096 | ||
1097 | set_buffer_jbddirty(bh); | |
1098 | ||
1099 | /* | |
1100 | * Metadata already on the current transaction list doesn't | |
1101 | * need to be filed. Metadata on another transaction's list must | |
1102 | * be committing, and will be refiled once the commit completes: | |
1103 | * leave it alone for now. | |
1104 | */ | |
1105 | if (jh->b_transaction != transaction) { | |
1106 | JBUFFER_TRACE(jh, "already on other transaction"); | |
1107 | J_ASSERT_JH(jh, jh->b_transaction == | |
1108 | journal->j_committing_transaction); | |
1109 | J_ASSERT_JH(jh, jh->b_next_transaction == transaction); | |
1110 | /* And this case is illegal: we can't reuse another | |
1111 | * transaction's data buffer, ever. */ | |
1112 | goto out_unlock_bh; | |
1113 | } | |
1114 | ||
1115 | /* That test should have eliminated the following case: */ | |
4019191b | 1116 | J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
470decc6 DK |
1117 | |
1118 | JBUFFER_TRACE(jh, "file as BJ_Metadata"); | |
1119 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 1120 | __jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata); |
470decc6 DK |
1121 | spin_unlock(&journal->j_list_lock); |
1122 | out_unlock_bh: | |
1123 | jbd_unlock_bh_state(bh); | |
1124 | out: | |
1125 | JBUFFER_TRACE(jh, "exit"); | |
1126 | return 0; | |
1127 | } | |
1128 | ||
1129 | /* | |
f7f4bccb | 1130 | * jbd2_journal_release_buffer: undo a get_write_access without any buffer |
470decc6 DK |
1131 | * updates, if the update decided in the end that it didn't need access. |
1132 | * | |
1133 | */ | |
1134 | void | |
f7f4bccb | 1135 | jbd2_journal_release_buffer(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1136 | { |
1137 | BUFFER_TRACE(bh, "entry"); | |
1138 | } | |
1139 | ||
1140 | /** | |
f7f4bccb | 1141 | * void jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
470decc6 DK |
1142 | * @handle: transaction handle |
1143 | * @bh: bh to 'forget' | |
1144 | * | |
1145 | * We can only do the bforget if there are no commits pending against the | |
1146 | * buffer. If the buffer is dirty in the current running transaction we | |
1147 | * can safely unlink it. | |
1148 | * | |
1149 | * bh may not be a journalled buffer at all - it may be a non-JBD | |
1150 | * buffer which came off the hashtable. Check for this. | |
1151 | * | |
1152 | * Decrements bh->b_count by one. | |
1153 | * | |
1154 | * Allow this call even if the handle has aborted --- it may be part of | |
1155 | * the caller's cleanup after an abort. | |
1156 | */ | |
f7f4bccb | 1157 | int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1158 | { |
1159 | transaction_t *transaction = handle->h_transaction; | |
1160 | journal_t *journal = transaction->t_journal; | |
1161 | struct journal_head *jh; | |
1162 | int drop_reserve = 0; | |
1163 | int err = 0; | |
1dfc3220 | 1164 | int was_modified = 0; |
470decc6 DK |
1165 | |
1166 | BUFFER_TRACE(bh, "entry"); | |
1167 | ||
1168 | jbd_lock_bh_state(bh); | |
1169 | spin_lock(&journal->j_list_lock); | |
1170 | ||
1171 | if (!buffer_jbd(bh)) | |
1172 | goto not_jbd; | |
1173 | jh = bh2jh(bh); | |
1174 | ||
1175 | /* Critical error: attempting to delete a bitmap buffer, maybe? | |
1176 | * Don't do any jbd operations, and return an error. */ | |
1177 | if (!J_EXPECT_JH(jh, !jh->b_committed_data, | |
1178 | "inconsistent data on disk")) { | |
1179 | err = -EIO; | |
1180 | goto not_jbd; | |
1181 | } | |
1182 | ||
1dfc3220 JB |
1183 | /* keep track of wether or not this transaction modified us */ |
1184 | was_modified = jh->b_modified; | |
1185 | ||
470decc6 DK |
1186 | /* |
1187 | * The buffer's going from the transaction, we must drop | |
1188 | * all references -bzzz | |
1189 | */ | |
1190 | jh->b_modified = 0; | |
1191 | ||
1192 | if (jh->b_transaction == handle->h_transaction) { | |
1193 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
1194 | ||
1195 | /* If we are forgetting a buffer which is already part | |
1196 | * of this transaction, then we can just drop it from | |
1197 | * the transaction immediately. */ | |
1198 | clear_buffer_dirty(bh); | |
1199 | clear_buffer_jbddirty(bh); | |
1200 | ||
1201 | JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); | |
1202 | ||
1dfc3220 JB |
1203 | /* |
1204 | * we only want to drop a reference if this transaction | |
1205 | * modified the buffer | |
1206 | */ | |
1207 | if (was_modified) | |
1208 | drop_reserve = 1; | |
470decc6 DK |
1209 | |
1210 | /* | |
1211 | * We are no longer going to journal this buffer. | |
1212 | * However, the commit of this transaction is still | |
1213 | * important to the buffer: the delete that we are now | |
1214 | * processing might obsolete an old log entry, so by | |
1215 | * committing, we can satisfy the buffer's checkpoint. | |
1216 | * | |
1217 | * So, if we have a checkpoint on the buffer, we should | |
1218 | * now refile the buffer on our BJ_Forget list so that | |
1219 | * we know to remove the checkpoint after we commit. | |
1220 | */ | |
1221 | ||
1222 | if (jh->b_cp_transaction) { | |
f7f4bccb MC |
1223 | __jbd2_journal_temp_unlink_buffer(jh); |
1224 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
470decc6 | 1225 | } else { |
f7f4bccb MC |
1226 | __jbd2_journal_unfile_buffer(jh); |
1227 | jbd2_journal_remove_journal_head(bh); | |
470decc6 DK |
1228 | __brelse(bh); |
1229 | if (!buffer_jbd(bh)) { | |
1230 | spin_unlock(&journal->j_list_lock); | |
1231 | jbd_unlock_bh_state(bh); | |
1232 | __bforget(bh); | |
1233 | goto drop; | |
1234 | } | |
1235 | } | |
1236 | } else if (jh->b_transaction) { | |
1237 | J_ASSERT_JH(jh, (jh->b_transaction == | |
1238 | journal->j_committing_transaction)); | |
1239 | /* However, if the buffer is still owned by a prior | |
1240 | * (committing) transaction, we can't drop it yet... */ | |
1241 | JBUFFER_TRACE(jh, "belongs to older transaction"); | |
1242 | /* ... but we CAN drop it from the new transaction if we | |
1243 | * have also modified it since the original commit. */ | |
1244 | ||
1245 | if (jh->b_next_transaction) { | |
1246 | J_ASSERT(jh->b_next_transaction == transaction); | |
1247 | jh->b_next_transaction = NULL; | |
1dfc3220 JB |
1248 | |
1249 | /* | |
1250 | * only drop a reference if this transaction modified | |
1251 | * the buffer | |
1252 | */ | |
1253 | if (was_modified) | |
1254 | drop_reserve = 1; | |
470decc6 DK |
1255 | } |
1256 | } | |
1257 | ||
1258 | not_jbd: | |
1259 | spin_unlock(&journal->j_list_lock); | |
1260 | jbd_unlock_bh_state(bh); | |
1261 | __brelse(bh); | |
1262 | drop: | |
1263 | if (drop_reserve) { | |
1264 | /* no need to reserve log space for this block -bzzz */ | |
1265 | handle->h_buffer_credits++; | |
1266 | } | |
1267 | return err; | |
1268 | } | |
1269 | ||
1270 | /** | |
f7f4bccb | 1271 | * int jbd2_journal_stop() - complete a transaction |
470decc6 DK |
1272 | * @handle: tranaction to complete. |
1273 | * | |
1274 | * All done for a particular handle. | |
1275 | * | |
1276 | * There is not much action needed here. We just return any remaining | |
1277 | * buffer credits to the transaction and remove the handle. The only | |
1278 | * complication is that we need to start a commit operation if the | |
1279 | * filesystem is marked for synchronous update. | |
1280 | * | |
f7f4bccb | 1281 | * jbd2_journal_stop itself will not usually return an error, but it may |
470decc6 | 1282 | * do so in unusual circumstances. In particular, expect it to |
f7f4bccb | 1283 | * return -EIO if a jbd2_journal_abort has been executed since the |
470decc6 DK |
1284 | * transaction began. |
1285 | */ | |
f7f4bccb | 1286 | int jbd2_journal_stop(handle_t *handle) |
470decc6 DK |
1287 | { |
1288 | transaction_t *transaction = handle->h_transaction; | |
1289 | journal_t *journal = transaction->t_journal; | |
a51dca9c TT |
1290 | int err, wait_for_commit = 0; |
1291 | tid_t tid; | |
470decc6 DK |
1292 | pid_t pid; |
1293 | ||
470decc6 DK |
1294 | J_ASSERT(journal_current_handle() == handle); |
1295 | ||
1296 | if (is_handle_aborted(handle)) | |
1297 | err = -EIO; | |
3e2a532b | 1298 | else { |
a51dca9c | 1299 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 | 1300 | err = 0; |
3e2a532b | 1301 | } |
470decc6 DK |
1302 | |
1303 | if (--handle->h_ref > 0) { | |
1304 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1305 | handle->h_ref); | |
1306 | return err; | |
1307 | } | |
1308 | ||
1309 | jbd_debug(4, "Handle %p going down\n", handle); | |
1310 | ||
1311 | /* | |
1312 | * Implement synchronous transaction batching. If the handle | |
1313 | * was synchronous, don't force a commit immediately. Let's | |
e07f7183 JB |
1314 | * yield and let another thread piggyback onto this |
1315 | * transaction. Keep doing that while new threads continue to | |
1316 | * arrive. It doesn't cost much - we're about to run a commit | |
1317 | * and sleep on IO anyway. Speeds up many-threaded, many-dir | |
1318 | * operations by 30x or more... | |
1319 | * | |
1320 | * We try and optimize the sleep time against what the | |
1321 | * underlying disk can do, instead of having a static sleep | |
1322 | * time. This is useful for the case where our storage is so | |
1323 | * fast that it is more optimal to go ahead and force a flush | |
1324 | * and wait for the transaction to be committed than it is to | |
1325 | * wait for an arbitrary amount of time for new writers to | |
1326 | * join the transaction. We achieve this by measuring how | |
1327 | * long it takes to commit a transaction, and compare it with | |
1328 | * how long this transaction has been running, and if run time | |
1329 | * < commit time then we sleep for the delta and commit. This | |
1330 | * greatly helps super fast disks that would see slowdowns as | |
1331 | * more threads started doing fsyncs. | |
470decc6 | 1332 | * |
e07f7183 JB |
1333 | * But don't do this if this process was the most recent one |
1334 | * to perform a synchronous write. We do this to detect the | |
1335 | * case where a single process is doing a stream of sync | |
1336 | * writes. No point in waiting for joiners in that case. | |
470decc6 DK |
1337 | */ |
1338 | pid = current->pid; | |
1339 | if (handle->h_sync && journal->j_last_sync_writer != pid) { | |
e07f7183 JB |
1340 | u64 commit_time, trans_time; |
1341 | ||
470decc6 | 1342 | journal->j_last_sync_writer = pid; |
e07f7183 | 1343 | |
a931da6a | 1344 | read_lock(&journal->j_state_lock); |
e07f7183 | 1345 | commit_time = journal->j_average_commit_time; |
a931da6a | 1346 | read_unlock(&journal->j_state_lock); |
e07f7183 JB |
1347 | |
1348 | trans_time = ktime_to_ns(ktime_sub(ktime_get(), | |
1349 | transaction->t_start_time)); | |
1350 | ||
30773840 TT |
1351 | commit_time = max_t(u64, commit_time, |
1352 | 1000*journal->j_min_batch_time); | |
e07f7183 | 1353 | commit_time = min_t(u64, commit_time, |
30773840 | 1354 | 1000*journal->j_max_batch_time); |
e07f7183 JB |
1355 | |
1356 | if (trans_time < commit_time) { | |
1357 | ktime_t expires = ktime_add_ns(ktime_get(), | |
1358 | commit_time); | |
1359 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1360 | schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); | |
1361 | } | |
470decc6 DK |
1362 | } |
1363 | ||
7058548c TT |
1364 | if (handle->h_sync) |
1365 | transaction->t_synchronous_commit = 1; | |
470decc6 | 1366 | current->journal_info = NULL; |
a51dca9c TT |
1367 | atomic_sub(handle->h_buffer_credits, |
1368 | &transaction->t_outstanding_credits); | |
470decc6 DK |
1369 | |
1370 | /* | |
1371 | * If the handle is marked SYNC, we need to set another commit | |
1372 | * going! We also want to force a commit if the current | |
1373 | * transaction is occupying too much of the log, or if the | |
1374 | * transaction is too old now. | |
1375 | */ | |
1376 | if (handle->h_sync || | |
a51dca9c TT |
1377 | (atomic_read(&transaction->t_outstanding_credits) > |
1378 | journal->j_max_transaction_buffers) || | |
1379 | time_after_eq(jiffies, transaction->t_expires)) { | |
470decc6 DK |
1380 | /* Do this even for aborted journals: an abort still |
1381 | * completes the commit thread, it just doesn't write | |
1382 | * anything to disk. */ | |
470decc6 | 1383 | |
470decc6 DK |
1384 | jbd_debug(2, "transaction too old, requesting commit for " |
1385 | "handle %p\n", handle); | |
1386 | /* This is non-blocking */ | |
c35a56a0 | 1387 | jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
1388 | |
1389 | /* | |
f7f4bccb | 1390 | * Special case: JBD2_SYNC synchronous updates require us |
470decc6 DK |
1391 | * to wait for the commit to complete. |
1392 | */ | |
1393 | if (handle->h_sync && !(current->flags & PF_MEMALLOC)) | |
a51dca9c | 1394 | wait_for_commit = 1; |
470decc6 DK |
1395 | } |
1396 | ||
a51dca9c TT |
1397 | /* |
1398 | * Once we drop t_updates, if it goes to zero the transaction | |
1399 | * could start commiting on us and eventually disappear. So | |
1400 | * once we do this, we must not dereference transaction | |
1401 | * pointer again. | |
1402 | */ | |
1403 | tid = transaction->t_tid; | |
1404 | if (atomic_dec_and_test(&transaction->t_updates)) { | |
1405 | wake_up(&journal->j_wait_updates); | |
1406 | if (journal->j_barrier_count) | |
1407 | wake_up(&journal->j_wait_transaction_locked); | |
1408 | } | |
1409 | ||
1410 | if (wait_for_commit) | |
1411 | err = jbd2_log_wait_commit(journal, tid); | |
1412 | ||
3295f0ef | 1413 | lock_map_release(&handle->h_lockdep_map); |
7b751066 | 1414 | |
af1e76d6 | 1415 | jbd2_free_handle(handle); |
470decc6 DK |
1416 | return err; |
1417 | } | |
1418 | ||
5648ba5b RD |
1419 | /** |
1420 | * int jbd2_journal_force_commit() - force any uncommitted transactions | |
470decc6 DK |
1421 | * @journal: journal to force |
1422 | * | |
1423 | * For synchronous operations: force any uncommitted transactions | |
1424 | * to disk. May seem kludgy, but it reuses all the handle batching | |
1425 | * code in a very simple manner. | |
1426 | */ | |
f7f4bccb | 1427 | int jbd2_journal_force_commit(journal_t *journal) |
470decc6 DK |
1428 | { |
1429 | handle_t *handle; | |
1430 | int ret; | |
1431 | ||
f7f4bccb | 1432 | handle = jbd2_journal_start(journal, 1); |
470decc6 DK |
1433 | if (IS_ERR(handle)) { |
1434 | ret = PTR_ERR(handle); | |
1435 | } else { | |
1436 | handle->h_sync = 1; | |
f7f4bccb | 1437 | ret = jbd2_journal_stop(handle); |
470decc6 DK |
1438 | } |
1439 | return ret; | |
1440 | } | |
1441 | ||
1442 | /* | |
1443 | * | |
1444 | * List management code snippets: various functions for manipulating the | |
1445 | * transaction buffer lists. | |
1446 | * | |
1447 | */ | |
1448 | ||
1449 | /* | |
1450 | * Append a buffer to a transaction list, given the transaction's list head | |
1451 | * pointer. | |
1452 | * | |
1453 | * j_list_lock is held. | |
1454 | * | |
1455 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1456 | */ | |
1457 | ||
1458 | static inline void | |
1459 | __blist_add_buffer(struct journal_head **list, struct journal_head *jh) | |
1460 | { | |
1461 | if (!*list) { | |
1462 | jh->b_tnext = jh->b_tprev = jh; | |
1463 | *list = jh; | |
1464 | } else { | |
1465 | /* Insert at the tail of the list to preserve order */ | |
1466 | struct journal_head *first = *list, *last = first->b_tprev; | |
1467 | jh->b_tprev = last; | |
1468 | jh->b_tnext = first; | |
1469 | last->b_tnext = first->b_tprev = jh; | |
1470 | } | |
1471 | } | |
1472 | ||
1473 | /* | |
1474 | * Remove a buffer from a transaction list, given the transaction's list | |
1475 | * head pointer. | |
1476 | * | |
1477 | * Called with j_list_lock held, and the journal may not be locked. | |
1478 | * | |
1479 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1480 | */ | |
1481 | ||
1482 | static inline void | |
1483 | __blist_del_buffer(struct journal_head **list, struct journal_head *jh) | |
1484 | { | |
1485 | if (*list == jh) { | |
1486 | *list = jh->b_tnext; | |
1487 | if (*list == jh) | |
1488 | *list = NULL; | |
1489 | } | |
1490 | jh->b_tprev->b_tnext = jh->b_tnext; | |
1491 | jh->b_tnext->b_tprev = jh->b_tprev; | |
1492 | } | |
1493 | ||
1494 | /* | |
1495 | * Remove a buffer from the appropriate transaction list. | |
1496 | * | |
1497 | * Note that this function can *change* the value of | |
87c89c23 JK |
1498 | * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list, |
1499 | * t_log_list or t_reserved_list. If the caller is holding onto a copy of one | |
1500 | * of these pointers, it could go bad. Generally the caller needs to re-read | |
1501 | * the pointer from the transaction_t. | |
470decc6 DK |
1502 | * |
1503 | * Called under j_list_lock. The journal may not be locked. | |
1504 | */ | |
f7f4bccb | 1505 | void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
470decc6 DK |
1506 | { |
1507 | struct journal_head **list = NULL; | |
1508 | transaction_t *transaction; | |
1509 | struct buffer_head *bh = jh2bh(jh); | |
1510 | ||
1511 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1512 | transaction = jh->b_transaction; | |
1513 | if (transaction) | |
1514 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1515 | ||
1516 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1517 | if (jh->b_jlist != BJ_None) | |
4019191b | 1518 | J_ASSERT_JH(jh, transaction != NULL); |
470decc6 DK |
1519 | |
1520 | switch (jh->b_jlist) { | |
1521 | case BJ_None: | |
1522 | return; | |
470decc6 DK |
1523 | case BJ_Metadata: |
1524 | transaction->t_nr_buffers--; | |
1525 | J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); | |
1526 | list = &transaction->t_buffers; | |
1527 | break; | |
1528 | case BJ_Forget: | |
1529 | list = &transaction->t_forget; | |
1530 | break; | |
1531 | case BJ_IO: | |
1532 | list = &transaction->t_iobuf_list; | |
1533 | break; | |
1534 | case BJ_Shadow: | |
1535 | list = &transaction->t_shadow_list; | |
1536 | break; | |
1537 | case BJ_LogCtl: | |
1538 | list = &transaction->t_log_list; | |
1539 | break; | |
1540 | case BJ_Reserved: | |
1541 | list = &transaction->t_reserved_list; | |
1542 | break; | |
470decc6 DK |
1543 | } |
1544 | ||
1545 | __blist_del_buffer(list, jh); | |
1546 | jh->b_jlist = BJ_None; | |
1547 | if (test_clear_buffer_jbddirty(bh)) | |
1548 | mark_buffer_dirty(bh); /* Expose it to the VM */ | |
1549 | } | |
1550 | ||
f7f4bccb | 1551 | void __jbd2_journal_unfile_buffer(struct journal_head *jh) |
470decc6 | 1552 | { |
f7f4bccb | 1553 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
1554 | jh->b_transaction = NULL; |
1555 | } | |
1556 | ||
f7f4bccb | 1557 | void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
1558 | { |
1559 | jbd_lock_bh_state(jh2bh(jh)); | |
1560 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 1561 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1562 | spin_unlock(&journal->j_list_lock); |
1563 | jbd_unlock_bh_state(jh2bh(jh)); | |
1564 | } | |
1565 | ||
1566 | /* | |
f7f4bccb | 1567 | * Called from jbd2_journal_try_to_free_buffers(). |
470decc6 DK |
1568 | * |
1569 | * Called under jbd_lock_bh_state(bh) | |
1570 | */ | |
1571 | static void | |
1572 | __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) | |
1573 | { | |
1574 | struct journal_head *jh; | |
1575 | ||
1576 | jh = bh2jh(bh); | |
1577 | ||
1578 | if (buffer_locked(bh) || buffer_dirty(bh)) | |
1579 | goto out; | |
1580 | ||
4019191b | 1581 | if (jh->b_next_transaction != NULL) |
470decc6 DK |
1582 | goto out; |
1583 | ||
1584 | spin_lock(&journal->j_list_lock); | |
87c89c23 | 1585 | if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) { |
470decc6 DK |
1586 | /* written-back checkpointed metadata buffer */ |
1587 | if (jh->b_jlist == BJ_None) { | |
1588 | JBUFFER_TRACE(jh, "remove from checkpoint list"); | |
f7f4bccb MC |
1589 | __jbd2_journal_remove_checkpoint(jh); |
1590 | jbd2_journal_remove_journal_head(bh); | |
470decc6 DK |
1591 | __brelse(bh); |
1592 | } | |
1593 | } | |
1594 | spin_unlock(&journal->j_list_lock); | |
1595 | out: | |
1596 | return; | |
1597 | } | |
1598 | ||
470decc6 | 1599 | /** |
f7f4bccb | 1600 | * int jbd2_journal_try_to_free_buffers() - try to free page buffers. |
470decc6 DK |
1601 | * @journal: journal for operation |
1602 | * @page: to try and free | |
530576bb MC |
1603 | * @gfp_mask: we use the mask to detect how hard should we try to release |
1604 | * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to | |
1605 | * release the buffers. | |
470decc6 DK |
1606 | * |
1607 | * | |
1608 | * For all the buffers on this page, | |
1609 | * if they are fully written out ordered data, move them onto BUF_CLEAN | |
1610 | * so try_to_free_buffers() can reap them. | |
1611 | * | |
1612 | * This function returns non-zero if we wish try_to_free_buffers() | |
1613 | * to be called. We do this if the page is releasable by try_to_free_buffers(). | |
1614 | * We also do it if the page has locked or dirty buffers and the caller wants | |
1615 | * us to perform sync or async writeout. | |
1616 | * | |
1617 | * This complicates JBD locking somewhat. We aren't protected by the | |
1618 | * BKL here. We wish to remove the buffer from its committing or | |
f7f4bccb | 1619 | * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
470decc6 DK |
1620 | * |
1621 | * This may *change* the value of transaction_t->t_datalist, so anyone | |
1622 | * who looks at t_datalist needs to lock against this function. | |
1623 | * | |
f7f4bccb MC |
1624 | * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
1625 | * buffer. So we need to lock against that. jbd2_journal_dirty_data() | |
470decc6 DK |
1626 | * will come out of the lock with the buffer dirty, which makes it |
1627 | * ineligible for release here. | |
1628 | * | |
1629 | * Who else is affected by this? hmm... Really the only contender | |
1630 | * is do_get_write_access() - it could be looking at the buffer while | |
1631 | * journal_try_to_free_buffer() is changing its state. But that | |
1632 | * cannot happen because we never reallocate freed data as metadata | |
1633 | * while the data is part of a transaction. Yes? | |
530576bb MC |
1634 | * |
1635 | * Return 0 on failure, 1 on success | |
470decc6 | 1636 | */ |
f7f4bccb | 1637 | int jbd2_journal_try_to_free_buffers(journal_t *journal, |
530576bb | 1638 | struct page *page, gfp_t gfp_mask) |
470decc6 DK |
1639 | { |
1640 | struct buffer_head *head; | |
1641 | struct buffer_head *bh; | |
1642 | int ret = 0; | |
1643 | ||
1644 | J_ASSERT(PageLocked(page)); | |
1645 | ||
1646 | head = page_buffers(page); | |
1647 | bh = head; | |
1648 | do { | |
1649 | struct journal_head *jh; | |
1650 | ||
1651 | /* | |
1652 | * We take our own ref against the journal_head here to avoid | |
1653 | * having to add tons of locking around each instance of | |
530576bb MC |
1654 | * jbd2_journal_remove_journal_head() and |
1655 | * jbd2_journal_put_journal_head(). | |
470decc6 | 1656 | */ |
f7f4bccb | 1657 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1658 | if (!jh) |
1659 | continue; | |
1660 | ||
1661 | jbd_lock_bh_state(bh); | |
1662 | __journal_try_to_free_buffer(journal, bh); | |
f7f4bccb | 1663 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1664 | jbd_unlock_bh_state(bh); |
1665 | if (buffer_jbd(bh)) | |
1666 | goto busy; | |
1667 | } while ((bh = bh->b_this_page) != head); | |
530576bb | 1668 | |
470decc6 | 1669 | ret = try_to_free_buffers(page); |
530576bb | 1670 | |
470decc6 DK |
1671 | busy: |
1672 | return ret; | |
1673 | } | |
1674 | ||
1675 | /* | |
1676 | * This buffer is no longer needed. If it is on an older transaction's | |
1677 | * checkpoint list we need to record it on this transaction's forget list | |
1678 | * to pin this buffer (and hence its checkpointing transaction) down until | |
1679 | * this transaction commits. If the buffer isn't on a checkpoint list, we | |
1680 | * release it. | |
1681 | * Returns non-zero if JBD no longer has an interest in the buffer. | |
1682 | * | |
1683 | * Called under j_list_lock. | |
1684 | * | |
1685 | * Called under jbd_lock_bh_state(bh). | |
1686 | */ | |
1687 | static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) | |
1688 | { | |
1689 | int may_free = 1; | |
1690 | struct buffer_head *bh = jh2bh(jh); | |
1691 | ||
f7f4bccb | 1692 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1693 | |
1694 | if (jh->b_cp_transaction) { | |
1695 | JBUFFER_TRACE(jh, "on running+cp transaction"); | |
f91d1d04 JK |
1696 | /* |
1697 | * We don't want to write the buffer anymore, clear the | |
1698 | * bit so that we don't confuse checks in | |
1699 | * __journal_file_buffer | |
1700 | */ | |
1701 | clear_buffer_dirty(bh); | |
f7f4bccb | 1702 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
470decc6 DK |
1703 | may_free = 0; |
1704 | } else { | |
1705 | JBUFFER_TRACE(jh, "on running transaction"); | |
f7f4bccb | 1706 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
1707 | __brelse(bh); |
1708 | } | |
1709 | return may_free; | |
1710 | } | |
1711 | ||
1712 | /* | |
f7f4bccb | 1713 | * jbd2_journal_invalidatepage |
470decc6 DK |
1714 | * |
1715 | * This code is tricky. It has a number of cases to deal with. | |
1716 | * | |
1717 | * There are two invariants which this code relies on: | |
1718 | * | |
1719 | * i_size must be updated on disk before we start calling invalidatepage on the | |
1720 | * data. | |
1721 | * | |
1722 | * This is done in ext3 by defining an ext3_setattr method which | |
1723 | * updates i_size before truncate gets going. By maintaining this | |
1724 | * invariant, we can be sure that it is safe to throw away any buffers | |
1725 | * attached to the current transaction: once the transaction commits, | |
1726 | * we know that the data will not be needed. | |
1727 | * | |
1728 | * Note however that we can *not* throw away data belonging to the | |
1729 | * previous, committing transaction! | |
1730 | * | |
1731 | * Any disk blocks which *are* part of the previous, committing | |
1732 | * transaction (and which therefore cannot be discarded immediately) are | |
1733 | * not going to be reused in the new running transaction | |
1734 | * | |
1735 | * The bitmap committed_data images guarantee this: any block which is | |
1736 | * allocated in one transaction and removed in the next will be marked | |
1737 | * as in-use in the committed_data bitmap, so cannot be reused until | |
1738 | * the next transaction to delete the block commits. This means that | |
1739 | * leaving committing buffers dirty is quite safe: the disk blocks | |
1740 | * cannot be reallocated to a different file and so buffer aliasing is | |
1741 | * not possible. | |
1742 | * | |
1743 | * | |
1744 | * The above applies mainly to ordered data mode. In writeback mode we | |
1745 | * don't make guarantees about the order in which data hits disk --- in | |
1746 | * particular we don't guarantee that new dirty data is flushed before | |
1747 | * transaction commit --- so it is always safe just to discard data | |
1748 | * immediately in that mode. --sct | |
1749 | */ | |
1750 | ||
1751 | /* | |
1752 | * The journal_unmap_buffer helper function returns zero if the buffer | |
1753 | * concerned remains pinned as an anonymous buffer belonging to an older | |
1754 | * transaction. | |
1755 | * | |
1756 | * We're outside-transaction here. Either or both of j_running_transaction | |
1757 | * and j_committing_transaction may be NULL. | |
1758 | */ | |
1759 | static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh) | |
1760 | { | |
1761 | transaction_t *transaction; | |
1762 | struct journal_head *jh; | |
1763 | int may_free = 1; | |
1764 | int ret; | |
1765 | ||
1766 | BUFFER_TRACE(bh, "entry"); | |
1767 | ||
1768 | /* | |
1769 | * It is safe to proceed here without the j_list_lock because the | |
1770 | * buffers cannot be stolen by try_to_free_buffers as long as we are | |
1771 | * holding the page lock. --sct | |
1772 | */ | |
1773 | ||
1774 | if (!buffer_jbd(bh)) | |
1775 | goto zap_buffer_unlocked; | |
1776 | ||
87c89c23 | 1777 | /* OK, we have data buffer in journaled mode */ |
a931da6a | 1778 | write_lock(&journal->j_state_lock); |
470decc6 DK |
1779 | jbd_lock_bh_state(bh); |
1780 | spin_lock(&journal->j_list_lock); | |
1781 | ||
f7f4bccb | 1782 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1783 | if (!jh) |
1784 | goto zap_buffer_no_jh; | |
1785 | ||
ba869023 | 1786 | /* |
1787 | * We cannot remove the buffer from checkpoint lists until the | |
1788 | * transaction adding inode to orphan list (let's call it T) | |
1789 | * is committed. Otherwise if the transaction changing the | |
1790 | * buffer would be cleaned from the journal before T is | |
1791 | * committed, a crash will cause that the correct contents of | |
1792 | * the buffer will be lost. On the other hand we have to | |
1793 | * clear the buffer dirty bit at latest at the moment when the | |
1794 | * transaction marking the buffer as freed in the filesystem | |
1795 | * structures is committed because from that moment on the | |
1796 | * buffer can be reallocated and used by a different page. | |
1797 | * Since the block hasn't been freed yet but the inode has | |
1798 | * already been added to orphan list, it is safe for us to add | |
1799 | * the buffer to BJ_Forget list of the newest transaction. | |
1800 | */ | |
470decc6 DK |
1801 | transaction = jh->b_transaction; |
1802 | if (transaction == NULL) { | |
1803 | /* First case: not on any transaction. If it | |
1804 | * has no checkpoint link, then we can zap it: | |
1805 | * it's a writeback-mode buffer so we don't care | |
1806 | * if it hits disk safely. */ | |
1807 | if (!jh->b_cp_transaction) { | |
1808 | JBUFFER_TRACE(jh, "not on any transaction: zap"); | |
1809 | goto zap_buffer; | |
1810 | } | |
1811 | ||
1812 | if (!buffer_dirty(bh)) { | |
1813 | /* bdflush has written it. We can drop it now */ | |
1814 | goto zap_buffer; | |
1815 | } | |
1816 | ||
1817 | /* OK, it must be in the journal but still not | |
1818 | * written fully to disk: it's metadata or | |
1819 | * journaled data... */ | |
1820 | ||
1821 | if (journal->j_running_transaction) { | |
1822 | /* ... and once the current transaction has | |
1823 | * committed, the buffer won't be needed any | |
1824 | * longer. */ | |
1825 | JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); | |
1826 | ret = __dispose_buffer(jh, | |
1827 | journal->j_running_transaction); | |
f7f4bccb | 1828 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1829 | spin_unlock(&journal->j_list_lock); |
1830 | jbd_unlock_bh_state(bh); | |
a931da6a | 1831 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1832 | return ret; |
1833 | } else { | |
1834 | /* There is no currently-running transaction. So the | |
1835 | * orphan record which we wrote for this file must have | |
1836 | * passed into commit. We must attach this buffer to | |
1837 | * the committing transaction, if it exists. */ | |
1838 | if (journal->j_committing_transaction) { | |
1839 | JBUFFER_TRACE(jh, "give to committing trans"); | |
1840 | ret = __dispose_buffer(jh, | |
1841 | journal->j_committing_transaction); | |
f7f4bccb | 1842 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1843 | spin_unlock(&journal->j_list_lock); |
1844 | jbd_unlock_bh_state(bh); | |
a931da6a | 1845 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1846 | return ret; |
1847 | } else { | |
1848 | /* The orphan record's transaction has | |
1849 | * committed. We can cleanse this buffer */ | |
1850 | clear_buffer_jbddirty(bh); | |
1851 | goto zap_buffer; | |
1852 | } | |
1853 | } | |
1854 | } else if (transaction == journal->j_committing_transaction) { | |
9b57988d | 1855 | JBUFFER_TRACE(jh, "on committing transaction"); |
470decc6 | 1856 | /* |
ba869023 | 1857 | * The buffer is committing, we simply cannot touch |
1858 | * it. So we just set j_next_transaction to the | |
1859 | * running transaction (if there is one) and mark | |
1860 | * buffer as freed so that commit code knows it should | |
1861 | * clear dirty bits when it is done with the buffer. | |
1862 | */ | |
470decc6 | 1863 | set_buffer_freed(bh); |
ba869023 | 1864 | if (journal->j_running_transaction && buffer_jbddirty(bh)) |
1865 | jh->b_next_transaction = journal->j_running_transaction; | |
f7f4bccb | 1866 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1867 | spin_unlock(&journal->j_list_lock); |
1868 | jbd_unlock_bh_state(bh); | |
a931da6a | 1869 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1870 | return 0; |
1871 | } else { | |
1872 | /* Good, the buffer belongs to the running transaction. | |
1873 | * We are writing our own transaction's data, not any | |
1874 | * previous one's, so it is safe to throw it away | |
1875 | * (remember that we expect the filesystem to have set | |
1876 | * i_size already for this truncate so recovery will not | |
1877 | * expose the disk blocks we are discarding here.) */ | |
1878 | J_ASSERT_JH(jh, transaction == journal->j_running_transaction); | |
9b57988d | 1879 | JBUFFER_TRACE(jh, "on running transaction"); |
470decc6 DK |
1880 | may_free = __dispose_buffer(jh, transaction); |
1881 | } | |
1882 | ||
1883 | zap_buffer: | |
f7f4bccb | 1884 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1885 | zap_buffer_no_jh: |
1886 | spin_unlock(&journal->j_list_lock); | |
1887 | jbd_unlock_bh_state(bh); | |
a931da6a | 1888 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
1889 | zap_buffer_unlocked: |
1890 | clear_buffer_dirty(bh); | |
1891 | J_ASSERT_BH(bh, !buffer_jbddirty(bh)); | |
1892 | clear_buffer_mapped(bh); | |
1893 | clear_buffer_req(bh); | |
1894 | clear_buffer_new(bh); | |
1895 | bh->b_bdev = NULL; | |
1896 | return may_free; | |
1897 | } | |
1898 | ||
1899 | /** | |
f7f4bccb | 1900 | * void jbd2_journal_invalidatepage() |
470decc6 DK |
1901 | * @journal: journal to use for flush... |
1902 | * @page: page to flush | |
1903 | * @offset: length of page to invalidate. | |
1904 | * | |
1905 | * Reap page buffers containing data after offset in page. | |
1906 | * | |
1907 | */ | |
f7f4bccb | 1908 | void jbd2_journal_invalidatepage(journal_t *journal, |
470decc6 DK |
1909 | struct page *page, |
1910 | unsigned long offset) | |
1911 | { | |
1912 | struct buffer_head *head, *bh, *next; | |
1913 | unsigned int curr_off = 0; | |
1914 | int may_free = 1; | |
1915 | ||
1916 | if (!PageLocked(page)) | |
1917 | BUG(); | |
1918 | if (!page_has_buffers(page)) | |
1919 | return; | |
1920 | ||
1921 | /* We will potentially be playing with lists other than just the | |
1922 | * data lists (especially for journaled data mode), so be | |
1923 | * cautious in our locking. */ | |
1924 | ||
1925 | head = bh = page_buffers(page); | |
1926 | do { | |
1927 | unsigned int next_off = curr_off + bh->b_size; | |
1928 | next = bh->b_this_page; | |
1929 | ||
1930 | if (offset <= curr_off) { | |
1931 | /* This block is wholly outside the truncation point */ | |
1932 | lock_buffer(bh); | |
1933 | may_free &= journal_unmap_buffer(journal, bh); | |
1934 | unlock_buffer(bh); | |
1935 | } | |
1936 | curr_off = next_off; | |
1937 | bh = next; | |
1938 | ||
1939 | } while (bh != head); | |
1940 | ||
1941 | if (!offset) { | |
1942 | if (may_free && try_to_free_buffers(page)) | |
1943 | J_ASSERT(!page_has_buffers(page)); | |
1944 | } | |
1945 | } | |
1946 | ||
1947 | /* | |
1948 | * File a buffer on the given transaction list. | |
1949 | */ | |
f7f4bccb | 1950 | void __jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
1951 | transaction_t *transaction, int jlist) |
1952 | { | |
1953 | struct journal_head **list = NULL; | |
1954 | int was_dirty = 0; | |
1955 | struct buffer_head *bh = jh2bh(jh); | |
1956 | ||
1957 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1958 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1959 | ||
1960 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1961 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
4019191b | 1962 | jh->b_transaction == NULL); |
470decc6 DK |
1963 | |
1964 | if (jh->b_transaction && jh->b_jlist == jlist) | |
1965 | return; | |
1966 | ||
470decc6 DK |
1967 | if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
1968 | jlist == BJ_Shadow || jlist == BJ_Forget) { | |
f91d1d04 JK |
1969 | /* |
1970 | * For metadata buffers, we track dirty bit in buffer_jbddirty | |
1971 | * instead of buffer_dirty. We should not see a dirty bit set | |
1972 | * here because we clear it in do_get_write_access but e.g. | |
1973 | * tune2fs can modify the sb and set the dirty bit at any time | |
1974 | * so we try to gracefully handle that. | |
1975 | */ | |
1976 | if (buffer_dirty(bh)) | |
1977 | warn_dirty_buffer(bh); | |
470decc6 DK |
1978 | if (test_clear_buffer_dirty(bh) || |
1979 | test_clear_buffer_jbddirty(bh)) | |
1980 | was_dirty = 1; | |
1981 | } | |
1982 | ||
1983 | if (jh->b_transaction) | |
f7f4bccb | 1984 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
1985 | jh->b_transaction = transaction; |
1986 | ||
1987 | switch (jlist) { | |
1988 | case BJ_None: | |
1989 | J_ASSERT_JH(jh, !jh->b_committed_data); | |
1990 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
1991 | return; | |
470decc6 DK |
1992 | case BJ_Metadata: |
1993 | transaction->t_nr_buffers++; | |
1994 | list = &transaction->t_buffers; | |
1995 | break; | |
1996 | case BJ_Forget: | |
1997 | list = &transaction->t_forget; | |
1998 | break; | |
1999 | case BJ_IO: | |
2000 | list = &transaction->t_iobuf_list; | |
2001 | break; | |
2002 | case BJ_Shadow: | |
2003 | list = &transaction->t_shadow_list; | |
2004 | break; | |
2005 | case BJ_LogCtl: | |
2006 | list = &transaction->t_log_list; | |
2007 | break; | |
2008 | case BJ_Reserved: | |
2009 | list = &transaction->t_reserved_list; | |
2010 | break; | |
470decc6 DK |
2011 | } |
2012 | ||
2013 | __blist_add_buffer(list, jh); | |
2014 | jh->b_jlist = jlist; | |
2015 | ||
2016 | if (was_dirty) | |
2017 | set_buffer_jbddirty(bh); | |
2018 | } | |
2019 | ||
f7f4bccb | 2020 | void jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2021 | transaction_t *transaction, int jlist) |
2022 | { | |
2023 | jbd_lock_bh_state(jh2bh(jh)); | |
2024 | spin_lock(&transaction->t_journal->j_list_lock); | |
f7f4bccb | 2025 | __jbd2_journal_file_buffer(jh, transaction, jlist); |
470decc6 DK |
2026 | spin_unlock(&transaction->t_journal->j_list_lock); |
2027 | jbd_unlock_bh_state(jh2bh(jh)); | |
2028 | } | |
2029 | ||
2030 | /* | |
2031 | * Remove a buffer from its current buffer list in preparation for | |
2032 | * dropping it from its current transaction entirely. If the buffer has | |
2033 | * already started to be used by a subsequent transaction, refile the | |
2034 | * buffer on that transaction's metadata list. | |
2035 | * | |
2036 | * Called under journal->j_list_lock | |
2037 | * | |
2038 | * Called under jbd_lock_bh_state(jh2bh(jh)) | |
2039 | */ | |
f7f4bccb | 2040 | void __jbd2_journal_refile_buffer(struct journal_head *jh) |
470decc6 | 2041 | { |
ba869023 | 2042 | int was_dirty, jlist; |
470decc6 DK |
2043 | struct buffer_head *bh = jh2bh(jh); |
2044 | ||
2045 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
2046 | if (jh->b_transaction) | |
2047 | assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); | |
2048 | ||
2049 | /* If the buffer is now unused, just drop it. */ | |
2050 | if (jh->b_next_transaction == NULL) { | |
f7f4bccb | 2051 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
2052 | return; |
2053 | } | |
2054 | ||
2055 | /* | |
2056 | * It has been modified by a later transaction: add it to the new | |
2057 | * transaction's metadata list. | |
2058 | */ | |
2059 | ||
2060 | was_dirty = test_clear_buffer_jbddirty(bh); | |
f7f4bccb | 2061 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
2062 | jh->b_transaction = jh->b_next_transaction; |
2063 | jh->b_next_transaction = NULL; | |
ba869023 | 2064 | if (buffer_freed(bh)) |
2065 | jlist = BJ_Forget; | |
2066 | else if (jh->b_modified) | |
2067 | jlist = BJ_Metadata; | |
2068 | else | |
2069 | jlist = BJ_Reserved; | |
2070 | __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist); | |
470decc6 DK |
2071 | J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
2072 | ||
2073 | if (was_dirty) | |
2074 | set_buffer_jbddirty(bh); | |
2075 | } | |
2076 | ||
2077 | /* | |
2078 | * For the unlocked version of this call, also make sure that any | |
2079 | * hanging journal_head is cleaned up if necessary. | |
2080 | * | |
f7f4bccb | 2081 | * __jbd2_journal_refile_buffer is usually called as part of a single locked |
470decc6 DK |
2082 | * operation on a buffer_head, in which the caller is probably going to |
2083 | * be hooking the journal_head onto other lists. In that case it is up | |
2084 | * to the caller to remove the journal_head if necessary. For the | |
f7f4bccb | 2085 | * unlocked jbd2_journal_refile_buffer call, the caller isn't going to be |
470decc6 DK |
2086 | * doing anything else to the buffer so we need to do the cleanup |
2087 | * ourselves to avoid a jh leak. | |
2088 | * | |
2089 | * *** The journal_head may be freed by this call! *** | |
2090 | */ | |
f7f4bccb | 2091 | void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
2092 | { |
2093 | struct buffer_head *bh = jh2bh(jh); | |
2094 | ||
2095 | jbd_lock_bh_state(bh); | |
2096 | spin_lock(&journal->j_list_lock); | |
2097 | ||
f7f4bccb | 2098 | __jbd2_journal_refile_buffer(jh); |
470decc6 | 2099 | jbd_unlock_bh_state(bh); |
f7f4bccb | 2100 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
2101 | |
2102 | spin_unlock(&journal->j_list_lock); | |
2103 | __brelse(bh); | |
2104 | } | |
c851ed54 JK |
2105 | |
2106 | /* | |
2107 | * File inode in the inode list of the handle's transaction | |
2108 | */ | |
2109 | int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode) | |
2110 | { | |
2111 | transaction_t *transaction = handle->h_transaction; | |
2112 | journal_t *journal = transaction->t_journal; | |
2113 | ||
2114 | if (is_handle_aborted(handle)) | |
2115 | return -EIO; | |
2116 | ||
2117 | jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, | |
2118 | transaction->t_tid); | |
2119 | ||
2120 | /* | |
2121 | * First check whether inode isn't already on the transaction's | |
2122 | * lists without taking the lock. Note that this check is safe | |
2123 | * without the lock as we cannot race with somebody removing inode | |
2124 | * from the transaction. The reason is that we remove inode from the | |
2125 | * transaction only in journal_release_jbd_inode() and when we commit | |
2126 | * the transaction. We are guarded from the first case by holding | |
2127 | * a reference to the inode. We are safe against the second case | |
2128 | * because if jinode->i_transaction == transaction, commit code | |
2129 | * cannot touch the transaction because we hold reference to it, | |
2130 | * and if jinode->i_next_transaction == transaction, commit code | |
2131 | * will only file the inode where we want it. | |
2132 | */ | |
2133 | if (jinode->i_transaction == transaction || | |
2134 | jinode->i_next_transaction == transaction) | |
2135 | return 0; | |
2136 | ||
2137 | spin_lock(&journal->j_list_lock); | |
2138 | ||
2139 | if (jinode->i_transaction == transaction || | |
2140 | jinode->i_next_transaction == transaction) | |
2141 | goto done; | |
2142 | ||
2143 | /* On some different transaction's list - should be | |
2144 | * the committing one */ | |
2145 | if (jinode->i_transaction) { | |
2146 | J_ASSERT(jinode->i_next_transaction == NULL); | |
2147 | J_ASSERT(jinode->i_transaction == | |
2148 | journal->j_committing_transaction); | |
2149 | jinode->i_next_transaction = transaction; | |
2150 | goto done; | |
2151 | } | |
2152 | /* Not on any transaction list... */ | |
2153 | J_ASSERT(!jinode->i_next_transaction); | |
2154 | jinode->i_transaction = transaction; | |
2155 | list_add(&jinode->i_list, &transaction->t_inode_list); | |
2156 | done: | |
2157 | spin_unlock(&journal->j_list_lock); | |
2158 | ||
2159 | return 0; | |
2160 | } | |
2161 | ||
2162 | /* | |
7f5aa215 JK |
2163 | * File truncate and transaction commit interact with each other in a |
2164 | * non-trivial way. If a transaction writing data block A is | |
2165 | * committing, we cannot discard the data by truncate until we have | |
2166 | * written them. Otherwise if we crashed after the transaction with | |
2167 | * write has committed but before the transaction with truncate has | |
2168 | * committed, we could see stale data in block A. This function is a | |
2169 | * helper to solve this problem. It starts writeout of the truncated | |
2170 | * part in case it is in the committing transaction. | |
2171 | * | |
2172 | * Filesystem code must call this function when inode is journaled in | |
2173 | * ordered mode before truncation happens and after the inode has been | |
2174 | * placed on orphan list with the new inode size. The second condition | |
2175 | * avoids the race that someone writes new data and we start | |
2176 | * committing the transaction after this function has been called but | |
2177 | * before a transaction for truncate is started (and furthermore it | |
2178 | * allows us to optimize the case where the addition to orphan list | |
2179 | * happens in the same transaction as write --- we don't have to write | |
2180 | * any data in such case). | |
c851ed54 | 2181 | */ |
7f5aa215 JK |
2182 | int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
2183 | struct jbd2_inode *jinode, | |
c851ed54 JK |
2184 | loff_t new_size) |
2185 | { | |
7f5aa215 | 2186 | transaction_t *inode_trans, *commit_trans; |
c851ed54 JK |
2187 | int ret = 0; |
2188 | ||
7f5aa215 JK |
2189 | /* This is a quick check to avoid locking if not necessary */ |
2190 | if (!jinode->i_transaction) | |
c851ed54 | 2191 | goto out; |
7f5aa215 JK |
2192 | /* Locks are here just to force reading of recent values, it is |
2193 | * enough that the transaction was not committing before we started | |
2194 | * a transaction adding the inode to orphan list */ | |
a931da6a | 2195 | read_lock(&journal->j_state_lock); |
c851ed54 | 2196 | commit_trans = journal->j_committing_transaction; |
a931da6a | 2197 | read_unlock(&journal->j_state_lock); |
7f5aa215 JK |
2198 | spin_lock(&journal->j_list_lock); |
2199 | inode_trans = jinode->i_transaction; | |
2200 | spin_unlock(&journal->j_list_lock); | |
2201 | if (inode_trans == commit_trans) { | |
2202 | ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, | |
c851ed54 JK |
2203 | new_size, LLONG_MAX); |
2204 | if (ret) | |
2205 | jbd2_journal_abort(journal, ret); | |
2206 | } | |
2207 | out: | |
2208 | return ret; | |
2209 | } |