Commit | Line | Data |
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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> |
470decc6 | 29 | |
7ddae860 AB |
30 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
31 | ||
470decc6 | 32 | /* |
f7f4bccb | 33 | * jbd2_get_transaction: obtain a new transaction_t object. |
470decc6 DK |
34 | * |
35 | * Simply allocate and initialise a new transaction. Create it in | |
36 | * RUNNING state and add it to the current journal (which should not | |
37 | * have an existing running transaction: we only make a new transaction | |
38 | * once we have started to commit the old one). | |
39 | * | |
40 | * Preconditions: | |
41 | * The journal MUST be locked. We don't perform atomic mallocs on the | |
42 | * new transaction and we can't block without protecting against other | |
43 | * processes trying to touch the journal while it is in transition. | |
44 | * | |
470decc6 DK |
45 | */ |
46 | ||
47 | static transaction_t * | |
f7f4bccb | 48 | jbd2_get_transaction(journal_t *journal, transaction_t *transaction) |
470decc6 DK |
49 | { |
50 | transaction->t_journal = journal; | |
51 | transaction->t_state = T_RUNNING; | |
e07f7183 | 52 | transaction->t_start_time = ktime_get(); |
470decc6 DK |
53 | transaction->t_tid = journal->j_transaction_sequence++; |
54 | transaction->t_expires = jiffies + journal->j_commit_interval; | |
55 | spin_lock_init(&transaction->t_handle_lock); | |
c851ed54 | 56 | INIT_LIST_HEAD(&transaction->t_inode_list); |
3e624fc7 | 57 | INIT_LIST_HEAD(&transaction->t_private_list); |
470decc6 DK |
58 | |
59 | /* Set up the commit timer for the new transaction. */ | |
b1f485f2 | 60 | journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
470decc6 DK |
61 | add_timer(&journal->j_commit_timer); |
62 | ||
63 | J_ASSERT(journal->j_running_transaction == NULL); | |
64 | journal->j_running_transaction = transaction; | |
8e85fb3f JL |
65 | transaction->t_max_wait = 0; |
66 | transaction->t_start = jiffies; | |
470decc6 DK |
67 | |
68 | return transaction; | |
69 | } | |
70 | ||
71 | /* | |
72 | * Handle management. | |
73 | * | |
74 | * A handle_t is an object which represents a single atomic update to a | |
75 | * filesystem, and which tracks all of the modifications which form part | |
76 | * of that one update. | |
77 | */ | |
78 | ||
79 | /* | |
80 | * start_this_handle: Given a handle, deal with any locking or stalling | |
81 | * needed to make sure that there is enough journal space for the handle | |
82 | * to begin. Attach the handle to a transaction and set up the | |
83 | * transaction's buffer credits. | |
84 | */ | |
85 | ||
86 | static int start_this_handle(journal_t *journal, handle_t *handle) | |
87 | { | |
88 | transaction_t *transaction; | |
89 | int needed; | |
90 | int nblocks = handle->h_buffer_credits; | |
91 | transaction_t *new_transaction = NULL; | |
92 | int ret = 0; | |
8e85fb3f | 93 | unsigned long ts = jiffies; |
470decc6 DK |
94 | |
95 | if (nblocks > journal->j_max_transaction_buffers) { | |
96 | printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n", | |
97 | current->comm, nblocks, | |
98 | journal->j_max_transaction_buffers); | |
99 | ret = -ENOSPC; | |
100 | goto out; | |
101 | } | |
102 | ||
103 | alloc_transaction: | |
104 | if (!journal->j_running_transaction) { | |
d802ffa8 | 105 | new_transaction = kzalloc(sizeof(*new_transaction), |
2d917969 | 106 | GFP_NOFS|__GFP_NOFAIL); |
470decc6 DK |
107 | if (!new_transaction) { |
108 | ret = -ENOMEM; | |
109 | goto out; | |
110 | } | |
470decc6 DK |
111 | } |
112 | ||
113 | jbd_debug(3, "New handle %p going live.\n", handle); | |
114 | ||
115 | repeat: | |
116 | ||
117 | /* | |
118 | * We need to hold j_state_lock until t_updates has been incremented, | |
119 | * for proper journal barrier handling | |
120 | */ | |
121 | spin_lock(&journal->j_state_lock); | |
122 | repeat_locked: | |
123 | if (is_journal_aborted(journal) || | |
f7f4bccb | 124 | (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
470decc6 DK |
125 | spin_unlock(&journal->j_state_lock); |
126 | ret = -EROFS; | |
127 | goto out; | |
128 | } | |
129 | ||
130 | /* Wait on the journal's transaction barrier if necessary */ | |
131 | if (journal->j_barrier_count) { | |
132 | spin_unlock(&journal->j_state_lock); | |
133 | wait_event(journal->j_wait_transaction_locked, | |
134 | journal->j_barrier_count == 0); | |
135 | goto repeat; | |
136 | } | |
137 | ||
138 | if (!journal->j_running_transaction) { | |
139 | if (!new_transaction) { | |
140 | spin_unlock(&journal->j_state_lock); | |
141 | goto alloc_transaction; | |
142 | } | |
f7f4bccb | 143 | jbd2_get_transaction(journal, new_transaction); |
470decc6 DK |
144 | new_transaction = NULL; |
145 | } | |
146 | ||
147 | transaction = journal->j_running_transaction; | |
148 | ||
149 | /* | |
150 | * If the current transaction is locked down for commit, wait for the | |
151 | * lock to be released. | |
152 | */ | |
153 | if (transaction->t_state == T_LOCKED) { | |
154 | DEFINE_WAIT(wait); | |
155 | ||
156 | prepare_to_wait(&journal->j_wait_transaction_locked, | |
157 | &wait, TASK_UNINTERRUPTIBLE); | |
158 | spin_unlock(&journal->j_state_lock); | |
159 | schedule(); | |
160 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
161 | goto repeat; | |
162 | } | |
163 | ||
164 | /* | |
165 | * If there is not enough space left in the log to write all potential | |
166 | * buffers requested by this operation, we need to stall pending a log | |
167 | * checkpoint to free some more log space. | |
168 | */ | |
169 | spin_lock(&transaction->t_handle_lock); | |
170 | needed = transaction->t_outstanding_credits + nblocks; | |
171 | ||
172 | if (needed > journal->j_max_transaction_buffers) { | |
173 | /* | |
174 | * If the current transaction is already too large, then start | |
175 | * to commit it: we can then go back and attach this handle to | |
176 | * a new transaction. | |
177 | */ | |
178 | DEFINE_WAIT(wait); | |
179 | ||
180 | jbd_debug(2, "Handle %p starting new commit...\n", handle); | |
181 | spin_unlock(&transaction->t_handle_lock); | |
182 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, | |
183 | TASK_UNINTERRUPTIBLE); | |
f7f4bccb | 184 | __jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
185 | spin_unlock(&journal->j_state_lock); |
186 | schedule(); | |
187 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
188 | goto repeat; | |
189 | } | |
190 | ||
191 | /* | |
192 | * The commit code assumes that it can get enough log space | |
193 | * without forcing a checkpoint. This is *critical* for | |
194 | * correctness: a checkpoint of a buffer which is also | |
195 | * associated with a committing transaction creates a deadlock, | |
196 | * so commit simply cannot force through checkpoints. | |
197 | * | |
198 | * We must therefore ensure the necessary space in the journal | |
199 | * *before* starting to dirty potentially checkpointed buffers | |
200 | * in the new transaction. | |
201 | * | |
202 | * The worst part is, any transaction currently committing can | |
203 | * reduce the free space arbitrarily. Be careful to account for | |
204 | * those buffers when checkpointing. | |
205 | */ | |
206 | ||
207 | /* | |
208 | * @@@ AKPM: This seems rather over-defensive. We're giving commit | |
209 | * a _lot_ of headroom: 1/4 of the journal plus the size of | |
210 | * the committing transaction. Really, we only need to give it | |
211 | * committing_transaction->t_outstanding_credits plus "enough" for | |
212 | * the log control blocks. | |
213 | * Also, this test is inconsitent with the matching one in | |
f7f4bccb | 214 | * jbd2_journal_extend(). |
470decc6 | 215 | */ |
f7f4bccb | 216 | if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) { |
470decc6 DK |
217 | jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle); |
218 | spin_unlock(&transaction->t_handle_lock); | |
f7f4bccb | 219 | __jbd2_log_wait_for_space(journal); |
470decc6 DK |
220 | goto repeat_locked; |
221 | } | |
222 | ||
223 | /* OK, account for the buffers that this operation expects to | |
224 | * use and add the handle to the running transaction. */ | |
225 | ||
8e85fb3f JL |
226 | if (time_after(transaction->t_start, ts)) { |
227 | ts = jbd2_time_diff(ts, transaction->t_start); | |
228 | if (ts > transaction->t_max_wait) | |
229 | transaction->t_max_wait = ts; | |
230 | } | |
231 | ||
470decc6 DK |
232 | handle->h_transaction = transaction; |
233 | transaction->t_outstanding_credits += nblocks; | |
234 | transaction->t_updates++; | |
235 | transaction->t_handle_count++; | |
236 | jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n", | |
237 | handle, nblocks, transaction->t_outstanding_credits, | |
f7f4bccb | 238 | __jbd2_log_space_left(journal)); |
470decc6 DK |
239 | spin_unlock(&transaction->t_handle_lock); |
240 | spin_unlock(&journal->j_state_lock); | |
9599b0e5 JK |
241 | |
242 | lock_map_acquire(&handle->h_lockdep_map); | |
470decc6 DK |
243 | out: |
244 | if (unlikely(new_transaction)) /* It's usually NULL */ | |
245 | kfree(new_transaction); | |
246 | return ret; | |
247 | } | |
248 | ||
7b751066 MC |
249 | static struct lock_class_key jbd2_handle_key; |
250 | ||
470decc6 DK |
251 | /* Allocate a new handle. This should probably be in a slab... */ |
252 | static handle_t *new_handle(int nblocks) | |
253 | { | |
af1e76d6 | 254 | handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
470decc6 DK |
255 | if (!handle) |
256 | return NULL; | |
257 | memset(handle, 0, sizeof(*handle)); | |
258 | handle->h_buffer_credits = nblocks; | |
259 | handle->h_ref = 1; | |
260 | ||
7b751066 MC |
261 | lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle", |
262 | &jbd2_handle_key, 0); | |
263 | ||
470decc6 DK |
264 | return handle; |
265 | } | |
266 | ||
267 | /** | |
f7f4bccb | 268 | * handle_t *jbd2_journal_start() - Obtain a new handle. |
470decc6 DK |
269 | * @journal: Journal to start transaction on. |
270 | * @nblocks: number of block buffer we might modify | |
271 | * | |
272 | * We make sure that the transaction can guarantee at least nblocks of | |
273 | * modified buffers in the log. We block until the log can guarantee | |
274 | * that much space. | |
275 | * | |
276 | * This function is visible to journal users (like ext3fs), so is not | |
277 | * called with the journal already locked. | |
278 | * | |
279 | * Return a pointer to a newly allocated handle, or NULL on failure | |
280 | */ | |
f7f4bccb | 281 | handle_t *jbd2_journal_start(journal_t *journal, int nblocks) |
470decc6 DK |
282 | { |
283 | handle_t *handle = journal_current_handle(); | |
284 | int err; | |
285 | ||
286 | if (!journal) | |
287 | return ERR_PTR(-EROFS); | |
288 | ||
289 | if (handle) { | |
290 | J_ASSERT(handle->h_transaction->t_journal == journal); | |
291 | handle->h_ref++; | |
292 | return handle; | |
293 | } | |
294 | ||
295 | handle = new_handle(nblocks); | |
296 | if (!handle) | |
297 | return ERR_PTR(-ENOMEM); | |
298 | ||
299 | current->journal_info = handle; | |
300 | ||
301 | err = start_this_handle(journal, handle); | |
302 | if (err < 0) { | |
af1e76d6 | 303 | jbd2_free_handle(handle); |
470decc6 DK |
304 | current->journal_info = NULL; |
305 | handle = ERR_PTR(err); | |
7b751066 | 306 | goto out; |
470decc6 | 307 | } |
7b751066 | 308 | out: |
470decc6 DK |
309 | return handle; |
310 | } | |
311 | ||
312 | /** | |
f7f4bccb | 313 | * int jbd2_journal_extend() - extend buffer credits. |
470decc6 DK |
314 | * @handle: handle to 'extend' |
315 | * @nblocks: nr blocks to try to extend by. | |
316 | * | |
317 | * Some transactions, such as large extends and truncates, can be done | |
318 | * atomically all at once or in several stages. The operation requests | |
319 | * a credit for a number of buffer modications in advance, but can | |
320 | * extend its credit if it needs more. | |
321 | * | |
f7f4bccb | 322 | * jbd2_journal_extend tries to give the running handle more buffer credits. |
470decc6 DK |
323 | * It does not guarantee that allocation - this is a best-effort only. |
324 | * The calling process MUST be able to deal cleanly with a failure to | |
325 | * extend here. | |
326 | * | |
327 | * Return 0 on success, non-zero on failure. | |
328 | * | |
329 | * return code < 0 implies an error | |
330 | * return code > 0 implies normal transaction-full status. | |
331 | */ | |
f7f4bccb | 332 | int jbd2_journal_extend(handle_t *handle, int nblocks) |
470decc6 DK |
333 | { |
334 | transaction_t *transaction = handle->h_transaction; | |
335 | journal_t *journal = transaction->t_journal; | |
336 | int result; | |
337 | int wanted; | |
338 | ||
339 | result = -EIO; | |
340 | if (is_handle_aborted(handle)) | |
341 | goto out; | |
342 | ||
343 | result = 1; | |
344 | ||
345 | spin_lock(&journal->j_state_lock); | |
346 | ||
347 | /* Don't extend a locked-down transaction! */ | |
348 | if (handle->h_transaction->t_state != T_RUNNING) { | |
349 | jbd_debug(3, "denied handle %p %d blocks: " | |
350 | "transaction not running\n", handle, nblocks); | |
351 | goto error_out; | |
352 | } | |
353 | ||
354 | spin_lock(&transaction->t_handle_lock); | |
355 | wanted = transaction->t_outstanding_credits + nblocks; | |
356 | ||
357 | if (wanted > journal->j_max_transaction_buffers) { | |
358 | jbd_debug(3, "denied handle %p %d blocks: " | |
359 | "transaction too large\n", handle, nblocks); | |
360 | goto unlock; | |
361 | } | |
362 | ||
f7f4bccb | 363 | if (wanted > __jbd2_log_space_left(journal)) { |
470decc6 DK |
364 | jbd_debug(3, "denied handle %p %d blocks: " |
365 | "insufficient log space\n", handle, nblocks); | |
366 | goto unlock; | |
367 | } | |
368 | ||
369 | handle->h_buffer_credits += nblocks; | |
370 | transaction->t_outstanding_credits += nblocks; | |
371 | result = 0; | |
372 | ||
373 | jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); | |
374 | unlock: | |
375 | spin_unlock(&transaction->t_handle_lock); | |
376 | error_out: | |
377 | spin_unlock(&journal->j_state_lock); | |
378 | out: | |
379 | return result; | |
380 | } | |
381 | ||
382 | ||
383 | /** | |
f7f4bccb | 384 | * int jbd2_journal_restart() - restart a handle . |
470decc6 DK |
385 | * @handle: handle to restart |
386 | * @nblocks: nr credits requested | |
387 | * | |
388 | * Restart a handle for a multi-transaction filesystem | |
389 | * operation. | |
390 | * | |
f7f4bccb MC |
391 | * If the jbd2_journal_extend() call above fails to grant new buffer credits |
392 | * to a running handle, a call to jbd2_journal_restart will commit the | |
470decc6 DK |
393 | * handle's transaction so far and reattach the handle to a new |
394 | * transaction capabable of guaranteeing the requested number of | |
395 | * credits. | |
396 | */ | |
397 | ||
f7f4bccb | 398 | int jbd2_journal_restart(handle_t *handle, int nblocks) |
470decc6 DK |
399 | { |
400 | transaction_t *transaction = handle->h_transaction; | |
401 | journal_t *journal = transaction->t_journal; | |
402 | int ret; | |
403 | ||
404 | /* If we've had an abort of any type, don't even think about | |
405 | * actually doing the restart! */ | |
406 | if (is_handle_aborted(handle)) | |
407 | return 0; | |
408 | ||
409 | /* | |
410 | * First unlink the handle from its current transaction, and start the | |
411 | * commit on that. | |
412 | */ | |
413 | J_ASSERT(transaction->t_updates > 0); | |
414 | J_ASSERT(journal_current_handle() == handle); | |
415 | ||
416 | spin_lock(&journal->j_state_lock); | |
417 | spin_lock(&transaction->t_handle_lock); | |
418 | transaction->t_outstanding_credits -= handle->h_buffer_credits; | |
419 | transaction->t_updates--; | |
420 | ||
421 | if (!transaction->t_updates) | |
422 | wake_up(&journal->j_wait_updates); | |
423 | spin_unlock(&transaction->t_handle_lock); | |
424 | ||
425 | jbd_debug(2, "restarting handle %p\n", handle); | |
f7f4bccb | 426 | __jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
427 | spin_unlock(&journal->j_state_lock); |
428 | ||
9599b0e5 | 429 | lock_map_release(&handle->h_lockdep_map); |
470decc6 DK |
430 | handle->h_buffer_credits = nblocks; |
431 | ret = start_this_handle(journal, handle); | |
432 | return ret; | |
433 | } | |
434 | ||
435 | ||
436 | /** | |
f7f4bccb | 437 | * void jbd2_journal_lock_updates () - establish a transaction barrier. |
470decc6 DK |
438 | * @journal: Journal to establish a barrier on. |
439 | * | |
440 | * This locks out any further updates from being started, and blocks | |
441 | * until all existing updates have completed, returning only once the | |
442 | * journal is in a quiescent state with no updates running. | |
443 | * | |
444 | * The journal lock should not be held on entry. | |
445 | */ | |
f7f4bccb | 446 | void jbd2_journal_lock_updates(journal_t *journal) |
470decc6 DK |
447 | { |
448 | DEFINE_WAIT(wait); | |
449 | ||
450 | spin_lock(&journal->j_state_lock); | |
451 | ++journal->j_barrier_count; | |
452 | ||
453 | /* Wait until there are no running updates */ | |
454 | while (1) { | |
455 | transaction_t *transaction = journal->j_running_transaction; | |
456 | ||
457 | if (!transaction) | |
458 | break; | |
459 | ||
460 | spin_lock(&transaction->t_handle_lock); | |
461 | if (!transaction->t_updates) { | |
462 | spin_unlock(&transaction->t_handle_lock); | |
463 | break; | |
464 | } | |
465 | prepare_to_wait(&journal->j_wait_updates, &wait, | |
466 | TASK_UNINTERRUPTIBLE); | |
467 | spin_unlock(&transaction->t_handle_lock); | |
468 | spin_unlock(&journal->j_state_lock); | |
469 | schedule(); | |
470 | finish_wait(&journal->j_wait_updates, &wait); | |
471 | spin_lock(&journal->j_state_lock); | |
472 | } | |
473 | spin_unlock(&journal->j_state_lock); | |
474 | ||
475 | /* | |
476 | * We have now established a barrier against other normal updates, but | |
f7f4bccb | 477 | * we also need to barrier against other jbd2_journal_lock_updates() calls |
470decc6 DK |
478 | * to make sure that we serialise special journal-locked operations |
479 | * too. | |
480 | */ | |
481 | mutex_lock(&journal->j_barrier); | |
482 | } | |
483 | ||
484 | /** | |
f7f4bccb | 485 | * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier |
470decc6 DK |
486 | * @journal: Journal to release the barrier on. |
487 | * | |
f7f4bccb | 488 | * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
470decc6 DK |
489 | * |
490 | * Should be called without the journal lock held. | |
491 | */ | |
f7f4bccb | 492 | void jbd2_journal_unlock_updates (journal_t *journal) |
470decc6 DK |
493 | { |
494 | J_ASSERT(journal->j_barrier_count != 0); | |
495 | ||
496 | mutex_unlock(&journal->j_barrier); | |
497 | spin_lock(&journal->j_state_lock); | |
498 | --journal->j_barrier_count; | |
499 | spin_unlock(&journal->j_state_lock); | |
500 | wake_up(&journal->j_wait_transaction_locked); | |
501 | } | |
502 | ||
f91d1d04 | 503 | static void warn_dirty_buffer(struct buffer_head *bh) |
470decc6 | 504 | { |
f91d1d04 | 505 | char b[BDEVNAME_SIZE]; |
470decc6 | 506 | |
f91d1d04 JK |
507 | printk(KERN_WARNING |
508 | "JBD: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). " | |
509 | "There's a risk of filesystem corruption in case of system " | |
510 | "crash.\n", | |
511 | bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr); | |
470decc6 DK |
512 | } |
513 | ||
514 | /* | |
515 | * If the buffer is already part of the current transaction, then there | |
516 | * is nothing we need to do. If it is already part of a prior | |
517 | * transaction which we are still committing to disk, then we need to | |
518 | * make sure that we do not overwrite the old copy: we do copy-out to | |
519 | * preserve the copy going to disk. We also account the buffer against | |
520 | * the handle's metadata buffer credits (unless the buffer is already | |
521 | * part of the transaction, that is). | |
522 | * | |
523 | */ | |
524 | static int | |
525 | do_get_write_access(handle_t *handle, struct journal_head *jh, | |
526 | int force_copy) | |
527 | { | |
528 | struct buffer_head *bh; | |
529 | transaction_t *transaction; | |
530 | journal_t *journal; | |
531 | int error; | |
532 | char *frozen_buffer = NULL; | |
533 | int need_copy = 0; | |
534 | ||
535 | if (is_handle_aborted(handle)) | |
536 | return -EROFS; | |
537 | ||
538 | transaction = handle->h_transaction; | |
539 | journal = transaction->t_journal; | |
540 | ||
541 | jbd_debug(5, "buffer_head %p, force_copy %d\n", jh, force_copy); | |
542 | ||
543 | JBUFFER_TRACE(jh, "entry"); | |
544 | repeat: | |
545 | bh = jh2bh(jh); | |
546 | ||
547 | /* @@@ Need to check for errors here at some point. */ | |
548 | ||
549 | lock_buffer(bh); | |
550 | jbd_lock_bh_state(bh); | |
551 | ||
552 | /* We now hold the buffer lock so it is safe to query the buffer | |
553 | * state. Is the buffer dirty? | |
554 | * | |
555 | * If so, there are two possibilities. The buffer may be | |
556 | * non-journaled, and undergoing a quite legitimate writeback. | |
557 | * Otherwise, it is journaled, and we don't expect dirty buffers | |
558 | * in that state (the buffers should be marked JBD_Dirty | |
559 | * instead.) So either the IO is being done under our own | |
560 | * control and this is a bug, or it's a third party IO such as | |
561 | * dump(8) (which may leave the buffer scheduled for read --- | |
562 | * ie. locked but not dirty) or tune2fs (which may actually have | |
563 | * the buffer dirtied, ugh.) */ | |
564 | ||
565 | if (buffer_dirty(bh)) { | |
566 | /* | |
567 | * First question: is this buffer already part of the current | |
568 | * transaction or the existing committing transaction? | |
569 | */ | |
570 | if (jh->b_transaction) { | |
571 | J_ASSERT_JH(jh, | |
572 | jh->b_transaction == transaction || | |
573 | jh->b_transaction == | |
574 | journal->j_committing_transaction); | |
575 | if (jh->b_next_transaction) | |
576 | J_ASSERT_JH(jh, jh->b_next_transaction == | |
577 | transaction); | |
f91d1d04 | 578 | warn_dirty_buffer(bh); |
470decc6 DK |
579 | } |
580 | /* | |
581 | * In any case we need to clean the dirty flag and we must | |
582 | * do it under the buffer lock to be sure we don't race | |
583 | * with running write-out. | |
584 | */ | |
f91d1d04 JK |
585 | JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
586 | clear_buffer_dirty(bh); | |
587 | set_buffer_jbddirty(bh); | |
470decc6 DK |
588 | } |
589 | ||
590 | unlock_buffer(bh); | |
591 | ||
592 | error = -EROFS; | |
593 | if (is_handle_aborted(handle)) { | |
594 | jbd_unlock_bh_state(bh); | |
595 | goto out; | |
596 | } | |
597 | error = 0; | |
598 | ||
599 | /* | |
600 | * The buffer is already part of this transaction if b_transaction or | |
601 | * b_next_transaction points to it | |
602 | */ | |
603 | if (jh->b_transaction == transaction || | |
604 | jh->b_next_transaction == transaction) | |
605 | goto done; | |
606 | ||
9fc7c63a JB |
607 | /* |
608 | * this is the first time this transaction is touching this buffer, | |
609 | * reset the modified flag | |
610 | */ | |
611 | jh->b_modified = 0; | |
612 | ||
470decc6 DK |
613 | /* |
614 | * If there is already a copy-out version of this buffer, then we don't | |
615 | * need to make another one | |
616 | */ | |
617 | if (jh->b_frozen_data) { | |
618 | JBUFFER_TRACE(jh, "has frozen data"); | |
619 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
620 | jh->b_next_transaction = transaction; | |
621 | goto done; | |
622 | } | |
623 | ||
624 | /* Is there data here we need to preserve? */ | |
625 | ||
626 | if (jh->b_transaction && jh->b_transaction != transaction) { | |
627 | JBUFFER_TRACE(jh, "owned by older transaction"); | |
628 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
629 | J_ASSERT_JH(jh, jh->b_transaction == | |
630 | journal->j_committing_transaction); | |
631 | ||
632 | /* There is one case we have to be very careful about. | |
633 | * If the committing transaction is currently writing | |
634 | * this buffer out to disk and has NOT made a copy-out, | |
635 | * then we cannot modify the buffer contents at all | |
636 | * right now. The essence of copy-out is that it is the | |
637 | * extra copy, not the primary copy, which gets | |
638 | * journaled. If the primary copy is already going to | |
639 | * disk then we cannot do copy-out here. */ | |
640 | ||
641 | if (jh->b_jlist == BJ_Shadow) { | |
642 | DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow); | |
643 | wait_queue_head_t *wqh; | |
644 | ||
645 | wqh = bit_waitqueue(&bh->b_state, BH_Unshadow); | |
646 | ||
647 | JBUFFER_TRACE(jh, "on shadow: sleep"); | |
648 | jbd_unlock_bh_state(bh); | |
649 | /* commit wakes up all shadow buffers after IO */ | |
650 | for ( ; ; ) { | |
651 | prepare_to_wait(wqh, &wait.wait, | |
652 | TASK_UNINTERRUPTIBLE); | |
653 | if (jh->b_jlist != BJ_Shadow) | |
654 | break; | |
655 | schedule(); | |
656 | } | |
657 | finish_wait(wqh, &wait.wait); | |
658 | goto repeat; | |
659 | } | |
660 | ||
661 | /* Only do the copy if the currently-owning transaction | |
662 | * still needs it. If it is on the Forget list, the | |
663 | * committing transaction is past that stage. The | |
664 | * buffer had better remain locked during the kmalloc, | |
665 | * but that should be true --- we hold the journal lock | |
666 | * still and the buffer is already on the BUF_JOURNAL | |
667 | * list so won't be flushed. | |
668 | * | |
669 | * Subtle point, though: if this is a get_undo_access, | |
670 | * then we will be relying on the frozen_data to contain | |
671 | * the new value of the committed_data record after the | |
672 | * transaction, so we HAVE to force the frozen_data copy | |
673 | * in that case. */ | |
674 | ||
675 | if (jh->b_jlist != BJ_Forget || force_copy) { | |
676 | JBUFFER_TRACE(jh, "generate frozen data"); | |
677 | if (!frozen_buffer) { | |
678 | JBUFFER_TRACE(jh, "allocate memory for buffer"); | |
679 | jbd_unlock_bh_state(bh); | |
680 | frozen_buffer = | |
af1e76d6 | 681 | jbd2_alloc(jh2bh(jh)->b_size, |
470decc6 DK |
682 | GFP_NOFS); |
683 | if (!frozen_buffer) { | |
684 | printk(KERN_EMERG | |
685 | "%s: OOM for frozen_buffer\n", | |
329d291f | 686 | __func__); |
470decc6 DK |
687 | JBUFFER_TRACE(jh, "oom!"); |
688 | error = -ENOMEM; | |
689 | jbd_lock_bh_state(bh); | |
690 | goto done; | |
691 | } | |
692 | goto repeat; | |
693 | } | |
694 | jh->b_frozen_data = frozen_buffer; | |
695 | frozen_buffer = NULL; | |
696 | need_copy = 1; | |
697 | } | |
698 | jh->b_next_transaction = transaction; | |
699 | } | |
700 | ||
701 | ||
702 | /* | |
703 | * Finally, if the buffer is not journaled right now, we need to make | |
704 | * sure it doesn't get written to disk before the caller actually | |
705 | * commits the new data | |
706 | */ | |
707 | if (!jh->b_transaction) { | |
708 | JBUFFER_TRACE(jh, "no transaction"); | |
709 | J_ASSERT_JH(jh, !jh->b_next_transaction); | |
710 | jh->b_transaction = transaction; | |
711 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); | |
712 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 713 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 DK |
714 | spin_unlock(&journal->j_list_lock); |
715 | } | |
716 | ||
717 | done: | |
718 | if (need_copy) { | |
719 | struct page *page; | |
720 | int offset; | |
721 | char *source; | |
722 | ||
723 | J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)), | |
724 | "Possible IO failure.\n"); | |
725 | page = jh2bh(jh)->b_page; | |
726 | offset = ((unsigned long) jh2bh(jh)->b_data) & ~PAGE_MASK; | |
727 | source = kmap_atomic(page, KM_USER0); | |
728 | memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size); | |
729 | kunmap_atomic(source, KM_USER0); | |
e06c8227 JB |
730 | |
731 | /* | |
732 | * Now that the frozen data is saved off, we need to store | |
733 | * any matching triggers. | |
734 | */ | |
735 | jh->b_frozen_triggers = jh->b_triggers; | |
470decc6 DK |
736 | } |
737 | jbd_unlock_bh_state(bh); | |
738 | ||
739 | /* | |
740 | * If we are about to journal a buffer, then any revoke pending on it is | |
741 | * no longer valid | |
742 | */ | |
f7f4bccb | 743 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 DK |
744 | |
745 | out: | |
746 | if (unlikely(frozen_buffer)) /* It's usually NULL */ | |
af1e76d6 | 747 | jbd2_free(frozen_buffer, bh->b_size); |
470decc6 DK |
748 | |
749 | JBUFFER_TRACE(jh, "exit"); | |
750 | return error; | |
751 | } | |
752 | ||
753 | /** | |
f7f4bccb | 754 | * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update. |
470decc6 DK |
755 | * @handle: transaction to add buffer modifications to |
756 | * @bh: bh to be used for metadata writes | |
757 | * @credits: variable that will receive credits for the buffer | |
758 | * | |
759 | * Returns an error code or 0 on success. | |
760 | * | |
761 | * In full data journalling mode the buffer may be of type BJ_AsyncData, | |
762 | * because we're write()ing a buffer which is also part of a shared mapping. | |
763 | */ | |
764 | ||
f7f4bccb | 765 | int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
470decc6 | 766 | { |
f7f4bccb | 767 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
768 | int rc; |
769 | ||
770 | /* We do not want to get caught playing with fields which the | |
771 | * log thread also manipulates. Make sure that the buffer | |
772 | * completes any outstanding IO before proceeding. */ | |
773 | rc = do_get_write_access(handle, jh, 0); | |
f7f4bccb | 774 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
775 | return rc; |
776 | } | |
777 | ||
778 | ||
779 | /* | |
780 | * When the user wants to journal a newly created buffer_head | |
781 | * (ie. getblk() returned a new buffer and we are going to populate it | |
782 | * manually rather than reading off disk), then we need to keep the | |
783 | * buffer_head locked until it has been completely filled with new | |
784 | * data. In this case, we should be able to make the assertion that | |
785 | * the bh is not already part of an existing transaction. | |
786 | * | |
787 | * The buffer should already be locked by the caller by this point. | |
788 | * There is no lock ranking violation: it was a newly created, | |
789 | * unlocked buffer beforehand. */ | |
790 | ||
791 | /** | |
f7f4bccb | 792 | * int jbd2_journal_get_create_access () - notify intent to use newly created bh |
470decc6 DK |
793 | * @handle: transaction to new buffer to |
794 | * @bh: new buffer. | |
795 | * | |
796 | * Call this if you create a new bh. | |
797 | */ | |
f7f4bccb | 798 | int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
799 | { |
800 | transaction_t *transaction = handle->h_transaction; | |
801 | journal_t *journal = transaction->t_journal; | |
f7f4bccb | 802 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
803 | int err; |
804 | ||
805 | jbd_debug(5, "journal_head %p\n", jh); | |
806 | err = -EROFS; | |
807 | if (is_handle_aborted(handle)) | |
808 | goto out; | |
809 | err = 0; | |
810 | ||
811 | JBUFFER_TRACE(jh, "entry"); | |
812 | /* | |
813 | * The buffer may already belong to this transaction due to pre-zeroing | |
814 | * in the filesystem's new_block code. It may also be on the previous, | |
815 | * committing transaction's lists, but it HAS to be in Forget state in | |
816 | * that case: the transaction must have deleted the buffer for it to be | |
817 | * reused here. | |
818 | */ | |
819 | jbd_lock_bh_state(bh); | |
820 | spin_lock(&journal->j_list_lock); | |
821 | J_ASSERT_JH(jh, (jh->b_transaction == transaction || | |
822 | jh->b_transaction == NULL || | |
823 | (jh->b_transaction == journal->j_committing_transaction && | |
824 | jh->b_jlist == BJ_Forget))); | |
825 | ||
826 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
827 | J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); | |
828 | ||
829 | if (jh->b_transaction == NULL) { | |
f91d1d04 JK |
830 | /* |
831 | * Previous jbd2_journal_forget() could have left the buffer | |
832 | * with jbddirty bit set because it was being committed. When | |
833 | * the commit finished, we've filed the buffer for | |
834 | * checkpointing and marked it dirty. Now we are reallocating | |
835 | * the buffer so the transaction freeing it must have | |
836 | * committed and so it's safe to clear the dirty bit. | |
837 | */ | |
838 | clear_buffer_dirty(jh2bh(jh)); | |
470decc6 | 839 | jh->b_transaction = transaction; |
9fc7c63a JB |
840 | |
841 | /* first access by this transaction */ | |
842 | jh->b_modified = 0; | |
843 | ||
470decc6 | 844 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
f7f4bccb | 845 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
470decc6 | 846 | } else if (jh->b_transaction == journal->j_committing_transaction) { |
9fc7c63a JB |
847 | /* first access by this transaction */ |
848 | jh->b_modified = 0; | |
849 | ||
470decc6 DK |
850 | JBUFFER_TRACE(jh, "set next transaction"); |
851 | jh->b_next_transaction = transaction; | |
852 | } | |
853 | spin_unlock(&journal->j_list_lock); | |
854 | jbd_unlock_bh_state(bh); | |
855 | ||
856 | /* | |
857 | * akpm: I added this. ext3_alloc_branch can pick up new indirect | |
858 | * blocks which contain freed but then revoked metadata. We need | |
859 | * to cancel the revoke in case we end up freeing it yet again | |
860 | * and the reallocating as data - this would cause a second revoke, | |
861 | * which hits an assertion error. | |
862 | */ | |
863 | JBUFFER_TRACE(jh, "cancelling revoke"); | |
f7f4bccb MC |
864 | jbd2_journal_cancel_revoke(handle, jh); |
865 | jbd2_journal_put_journal_head(jh); | |
470decc6 DK |
866 | out: |
867 | return err; | |
868 | } | |
869 | ||
870 | /** | |
f7f4bccb | 871 | * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
470decc6 DK |
872 | * non-rewindable consequences |
873 | * @handle: transaction | |
874 | * @bh: buffer to undo | |
875 | * @credits: store the number of taken credits here (if not NULL) | |
876 | * | |
877 | * Sometimes there is a need to distinguish between metadata which has | |
878 | * been committed to disk and that which has not. The ext3fs code uses | |
879 | * this for freeing and allocating space, we have to make sure that we | |
880 | * do not reuse freed space until the deallocation has been committed, | |
881 | * since if we overwrote that space we would make the delete | |
882 | * un-rewindable in case of a crash. | |
883 | * | |
f7f4bccb | 884 | * To deal with that, jbd2_journal_get_undo_access requests write access to a |
470decc6 DK |
885 | * buffer for parts of non-rewindable operations such as delete |
886 | * operations on the bitmaps. The journaling code must keep a copy of | |
887 | * the buffer's contents prior to the undo_access call until such time | |
888 | * as we know that the buffer has definitely been committed to disk. | |
889 | * | |
890 | * We never need to know which transaction the committed data is part | |
891 | * of, buffers touched here are guaranteed to be dirtied later and so | |
892 | * will be committed to a new transaction in due course, at which point | |
893 | * we can discard the old committed data pointer. | |
894 | * | |
895 | * Returns error number or 0 on success. | |
896 | */ | |
f7f4bccb | 897 | int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
898 | { |
899 | int err; | |
f7f4bccb | 900 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
901 | char *committed_data = NULL; |
902 | ||
903 | JBUFFER_TRACE(jh, "entry"); | |
904 | ||
905 | /* | |
906 | * Do this first --- it can drop the journal lock, so we want to | |
907 | * make sure that obtaining the committed_data is done | |
908 | * atomically wrt. completion of any outstanding commits. | |
909 | */ | |
910 | err = do_get_write_access(handle, jh, 1); | |
911 | if (err) | |
912 | goto out; | |
913 | ||
914 | repeat: | |
915 | if (!jh->b_committed_data) { | |
af1e76d6 | 916 | committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); |
470decc6 DK |
917 | if (!committed_data) { |
918 | printk(KERN_EMERG "%s: No memory for committed data\n", | |
329d291f | 919 | __func__); |
470decc6 DK |
920 | err = -ENOMEM; |
921 | goto out; | |
922 | } | |
923 | } | |
924 | ||
925 | jbd_lock_bh_state(bh); | |
926 | if (!jh->b_committed_data) { | |
927 | /* Copy out the current buffer contents into the | |
928 | * preserved, committed copy. */ | |
929 | JBUFFER_TRACE(jh, "generate b_committed data"); | |
930 | if (!committed_data) { | |
931 | jbd_unlock_bh_state(bh); | |
932 | goto repeat; | |
933 | } | |
934 | ||
935 | jh->b_committed_data = committed_data; | |
936 | committed_data = NULL; | |
937 | memcpy(jh->b_committed_data, bh->b_data, bh->b_size); | |
938 | } | |
939 | jbd_unlock_bh_state(bh); | |
940 | out: | |
f7f4bccb | 941 | jbd2_journal_put_journal_head(jh); |
470decc6 | 942 | if (unlikely(committed_data)) |
af1e76d6 | 943 | jbd2_free(committed_data, bh->b_size); |
470decc6 DK |
944 | return err; |
945 | } | |
946 | ||
e06c8227 JB |
947 | /** |
948 | * void jbd2_journal_set_triggers() - Add triggers for commit writeout | |
949 | * @bh: buffer to trigger on | |
950 | * @type: struct jbd2_buffer_trigger_type containing the trigger(s). | |
951 | * | |
952 | * Set any triggers on this journal_head. This is always safe, because | |
953 | * triggers for a committing buffer will be saved off, and triggers for | |
954 | * a running transaction will match the buffer in that transaction. | |
955 | * | |
956 | * Call with NULL to clear the triggers. | |
957 | */ | |
958 | void jbd2_journal_set_triggers(struct buffer_head *bh, | |
959 | struct jbd2_buffer_trigger_type *type) | |
960 | { | |
961 | struct journal_head *jh = bh2jh(bh); | |
962 | ||
963 | jh->b_triggers = type; | |
964 | } | |
965 | ||
966 | void jbd2_buffer_commit_trigger(struct journal_head *jh, void *mapped_data, | |
967 | struct jbd2_buffer_trigger_type *triggers) | |
968 | { | |
969 | struct buffer_head *bh = jh2bh(jh); | |
970 | ||
971 | if (!triggers || !triggers->t_commit) | |
972 | return; | |
973 | ||
974 | triggers->t_commit(triggers, bh, mapped_data, bh->b_size); | |
975 | } | |
976 | ||
977 | void jbd2_buffer_abort_trigger(struct journal_head *jh, | |
978 | struct jbd2_buffer_trigger_type *triggers) | |
979 | { | |
980 | if (!triggers || !triggers->t_abort) | |
981 | return; | |
982 | ||
983 | triggers->t_abort(triggers, jh2bh(jh)); | |
984 | } | |
985 | ||
986 | ||
987 | ||
470decc6 | 988 | /** |
f7f4bccb | 989 | * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
470decc6 DK |
990 | * @handle: transaction to add buffer to. |
991 | * @bh: buffer to mark | |
992 | * | |
993 | * mark dirty metadata which needs to be journaled as part of the current | |
994 | * transaction. | |
995 | * | |
996 | * The buffer is placed on the transaction's metadata list and is marked | |
997 | * as belonging to the transaction. | |
998 | * | |
999 | * Returns error number or 0 on success. | |
1000 | * | |
1001 | * Special care needs to be taken if the buffer already belongs to the | |
1002 | * current committing transaction (in which case we should have frozen | |
1003 | * data present for that commit). In that case, we don't relink the | |
1004 | * buffer: that only gets done when the old transaction finally | |
1005 | * completes its commit. | |
1006 | */ | |
f7f4bccb | 1007 | int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1008 | { |
1009 | transaction_t *transaction = handle->h_transaction; | |
1010 | journal_t *journal = transaction->t_journal; | |
1011 | struct journal_head *jh = bh2jh(bh); | |
1012 | ||
1013 | jbd_debug(5, "journal_head %p\n", jh); | |
1014 | JBUFFER_TRACE(jh, "entry"); | |
1015 | if (is_handle_aborted(handle)) | |
1016 | goto out; | |
1017 | ||
1018 | jbd_lock_bh_state(bh); | |
1019 | ||
1020 | if (jh->b_modified == 0) { | |
1021 | /* | |
1022 | * This buffer's got modified and becoming part | |
1023 | * of the transaction. This needs to be done | |
1024 | * once a transaction -bzzz | |
1025 | */ | |
1026 | jh->b_modified = 1; | |
1027 | J_ASSERT_JH(jh, handle->h_buffer_credits > 0); | |
1028 | handle->h_buffer_credits--; | |
1029 | } | |
1030 | ||
1031 | /* | |
1032 | * fastpath, to avoid expensive locking. If this buffer is already | |
1033 | * on the running transaction's metadata list there is nothing to do. | |
1034 | * Nobody can take it off again because there is a handle open. | |
1035 | * I _think_ we're OK here with SMP barriers - a mistaken decision will | |
1036 | * result in this test being false, so we go in and take the locks. | |
1037 | */ | |
1038 | if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { | |
1039 | JBUFFER_TRACE(jh, "fastpath"); | |
1040 | J_ASSERT_JH(jh, jh->b_transaction == | |
1041 | journal->j_running_transaction); | |
1042 | goto out_unlock_bh; | |
1043 | } | |
1044 | ||
1045 | set_buffer_jbddirty(bh); | |
1046 | ||
1047 | /* | |
1048 | * Metadata already on the current transaction list doesn't | |
1049 | * need to be filed. Metadata on another transaction's list must | |
1050 | * be committing, and will be refiled once the commit completes: | |
1051 | * leave it alone for now. | |
1052 | */ | |
1053 | if (jh->b_transaction != transaction) { | |
1054 | JBUFFER_TRACE(jh, "already on other transaction"); | |
1055 | J_ASSERT_JH(jh, jh->b_transaction == | |
1056 | journal->j_committing_transaction); | |
1057 | J_ASSERT_JH(jh, jh->b_next_transaction == transaction); | |
1058 | /* And this case is illegal: we can't reuse another | |
1059 | * transaction's data buffer, ever. */ | |
1060 | goto out_unlock_bh; | |
1061 | } | |
1062 | ||
1063 | /* That test should have eliminated the following case: */ | |
4019191b | 1064 | J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
470decc6 DK |
1065 | |
1066 | JBUFFER_TRACE(jh, "file as BJ_Metadata"); | |
1067 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 1068 | __jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata); |
470decc6 DK |
1069 | spin_unlock(&journal->j_list_lock); |
1070 | out_unlock_bh: | |
1071 | jbd_unlock_bh_state(bh); | |
1072 | out: | |
1073 | JBUFFER_TRACE(jh, "exit"); | |
1074 | return 0; | |
1075 | } | |
1076 | ||
1077 | /* | |
f7f4bccb | 1078 | * jbd2_journal_release_buffer: undo a get_write_access without any buffer |
470decc6 DK |
1079 | * updates, if the update decided in the end that it didn't need access. |
1080 | * | |
1081 | */ | |
1082 | void | |
f7f4bccb | 1083 | jbd2_journal_release_buffer(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1084 | { |
1085 | BUFFER_TRACE(bh, "entry"); | |
1086 | } | |
1087 | ||
1088 | /** | |
f7f4bccb | 1089 | * void jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
470decc6 DK |
1090 | * @handle: transaction handle |
1091 | * @bh: bh to 'forget' | |
1092 | * | |
1093 | * We can only do the bforget if there are no commits pending against the | |
1094 | * buffer. If the buffer is dirty in the current running transaction we | |
1095 | * can safely unlink it. | |
1096 | * | |
1097 | * bh may not be a journalled buffer at all - it may be a non-JBD | |
1098 | * buffer which came off the hashtable. Check for this. | |
1099 | * | |
1100 | * Decrements bh->b_count by one. | |
1101 | * | |
1102 | * Allow this call even if the handle has aborted --- it may be part of | |
1103 | * the caller's cleanup after an abort. | |
1104 | */ | |
f7f4bccb | 1105 | int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1106 | { |
1107 | transaction_t *transaction = handle->h_transaction; | |
1108 | journal_t *journal = transaction->t_journal; | |
1109 | struct journal_head *jh; | |
1110 | int drop_reserve = 0; | |
1111 | int err = 0; | |
1dfc3220 | 1112 | int was_modified = 0; |
470decc6 DK |
1113 | |
1114 | BUFFER_TRACE(bh, "entry"); | |
1115 | ||
1116 | jbd_lock_bh_state(bh); | |
1117 | spin_lock(&journal->j_list_lock); | |
1118 | ||
1119 | if (!buffer_jbd(bh)) | |
1120 | goto not_jbd; | |
1121 | jh = bh2jh(bh); | |
1122 | ||
1123 | /* Critical error: attempting to delete a bitmap buffer, maybe? | |
1124 | * Don't do any jbd operations, and return an error. */ | |
1125 | if (!J_EXPECT_JH(jh, !jh->b_committed_data, | |
1126 | "inconsistent data on disk")) { | |
1127 | err = -EIO; | |
1128 | goto not_jbd; | |
1129 | } | |
1130 | ||
1dfc3220 JB |
1131 | /* keep track of wether or not this transaction modified us */ |
1132 | was_modified = jh->b_modified; | |
1133 | ||
470decc6 DK |
1134 | /* |
1135 | * The buffer's going from the transaction, we must drop | |
1136 | * all references -bzzz | |
1137 | */ | |
1138 | jh->b_modified = 0; | |
1139 | ||
1140 | if (jh->b_transaction == handle->h_transaction) { | |
1141 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
1142 | ||
1143 | /* If we are forgetting a buffer which is already part | |
1144 | * of this transaction, then we can just drop it from | |
1145 | * the transaction immediately. */ | |
1146 | clear_buffer_dirty(bh); | |
1147 | clear_buffer_jbddirty(bh); | |
1148 | ||
1149 | JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); | |
1150 | ||
1dfc3220 JB |
1151 | /* |
1152 | * we only want to drop a reference if this transaction | |
1153 | * modified the buffer | |
1154 | */ | |
1155 | if (was_modified) | |
1156 | drop_reserve = 1; | |
470decc6 DK |
1157 | |
1158 | /* | |
1159 | * We are no longer going to journal this buffer. | |
1160 | * However, the commit of this transaction is still | |
1161 | * important to the buffer: the delete that we are now | |
1162 | * processing might obsolete an old log entry, so by | |
1163 | * committing, we can satisfy the buffer's checkpoint. | |
1164 | * | |
1165 | * So, if we have a checkpoint on the buffer, we should | |
1166 | * now refile the buffer on our BJ_Forget list so that | |
1167 | * we know to remove the checkpoint after we commit. | |
1168 | */ | |
1169 | ||
1170 | if (jh->b_cp_transaction) { | |
f7f4bccb MC |
1171 | __jbd2_journal_temp_unlink_buffer(jh); |
1172 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
470decc6 | 1173 | } else { |
f7f4bccb MC |
1174 | __jbd2_journal_unfile_buffer(jh); |
1175 | jbd2_journal_remove_journal_head(bh); | |
470decc6 DK |
1176 | __brelse(bh); |
1177 | if (!buffer_jbd(bh)) { | |
1178 | spin_unlock(&journal->j_list_lock); | |
1179 | jbd_unlock_bh_state(bh); | |
1180 | __bforget(bh); | |
1181 | goto drop; | |
1182 | } | |
1183 | } | |
1184 | } else if (jh->b_transaction) { | |
1185 | J_ASSERT_JH(jh, (jh->b_transaction == | |
1186 | journal->j_committing_transaction)); | |
1187 | /* However, if the buffer is still owned by a prior | |
1188 | * (committing) transaction, we can't drop it yet... */ | |
1189 | JBUFFER_TRACE(jh, "belongs to older transaction"); | |
1190 | /* ... but we CAN drop it from the new transaction if we | |
1191 | * have also modified it since the original commit. */ | |
1192 | ||
1193 | if (jh->b_next_transaction) { | |
1194 | J_ASSERT(jh->b_next_transaction == transaction); | |
1195 | jh->b_next_transaction = NULL; | |
1dfc3220 JB |
1196 | |
1197 | /* | |
1198 | * only drop a reference if this transaction modified | |
1199 | * the buffer | |
1200 | */ | |
1201 | if (was_modified) | |
1202 | drop_reserve = 1; | |
470decc6 DK |
1203 | } |
1204 | } | |
1205 | ||
1206 | not_jbd: | |
1207 | spin_unlock(&journal->j_list_lock); | |
1208 | jbd_unlock_bh_state(bh); | |
1209 | __brelse(bh); | |
1210 | drop: | |
1211 | if (drop_reserve) { | |
1212 | /* no need to reserve log space for this block -bzzz */ | |
1213 | handle->h_buffer_credits++; | |
1214 | } | |
1215 | return err; | |
1216 | } | |
1217 | ||
1218 | /** | |
f7f4bccb | 1219 | * int jbd2_journal_stop() - complete a transaction |
470decc6 DK |
1220 | * @handle: tranaction to complete. |
1221 | * | |
1222 | * All done for a particular handle. | |
1223 | * | |
1224 | * There is not much action needed here. We just return any remaining | |
1225 | * buffer credits to the transaction and remove the handle. The only | |
1226 | * complication is that we need to start a commit operation if the | |
1227 | * filesystem is marked for synchronous update. | |
1228 | * | |
f7f4bccb | 1229 | * jbd2_journal_stop itself will not usually return an error, but it may |
470decc6 | 1230 | * do so in unusual circumstances. In particular, expect it to |
f7f4bccb | 1231 | * return -EIO if a jbd2_journal_abort has been executed since the |
470decc6 DK |
1232 | * transaction began. |
1233 | */ | |
f7f4bccb | 1234 | int jbd2_journal_stop(handle_t *handle) |
470decc6 DK |
1235 | { |
1236 | transaction_t *transaction = handle->h_transaction; | |
1237 | journal_t *journal = transaction->t_journal; | |
e07f7183 | 1238 | int err; |
470decc6 DK |
1239 | pid_t pid; |
1240 | ||
470decc6 DK |
1241 | J_ASSERT(journal_current_handle() == handle); |
1242 | ||
1243 | if (is_handle_aborted(handle)) | |
1244 | err = -EIO; | |
3e2a532b OH |
1245 | else { |
1246 | J_ASSERT(transaction->t_updates > 0); | |
470decc6 | 1247 | err = 0; |
3e2a532b | 1248 | } |
470decc6 DK |
1249 | |
1250 | if (--handle->h_ref > 0) { | |
1251 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1252 | handle->h_ref); | |
1253 | return err; | |
1254 | } | |
1255 | ||
1256 | jbd_debug(4, "Handle %p going down\n", handle); | |
1257 | ||
1258 | /* | |
1259 | * Implement synchronous transaction batching. If the handle | |
1260 | * was synchronous, don't force a commit immediately. Let's | |
e07f7183 JB |
1261 | * yield and let another thread piggyback onto this |
1262 | * transaction. Keep doing that while new threads continue to | |
1263 | * arrive. It doesn't cost much - we're about to run a commit | |
1264 | * and sleep on IO anyway. Speeds up many-threaded, many-dir | |
1265 | * operations by 30x or more... | |
1266 | * | |
1267 | * We try and optimize the sleep time against what the | |
1268 | * underlying disk can do, instead of having a static sleep | |
1269 | * time. This is useful for the case where our storage is so | |
1270 | * fast that it is more optimal to go ahead and force a flush | |
1271 | * and wait for the transaction to be committed than it is to | |
1272 | * wait for an arbitrary amount of time for new writers to | |
1273 | * join the transaction. We achieve this by measuring how | |
1274 | * long it takes to commit a transaction, and compare it with | |
1275 | * how long this transaction has been running, and if run time | |
1276 | * < commit time then we sleep for the delta and commit. This | |
1277 | * greatly helps super fast disks that would see slowdowns as | |
1278 | * more threads started doing fsyncs. | |
470decc6 | 1279 | * |
e07f7183 JB |
1280 | * But don't do this if this process was the most recent one |
1281 | * to perform a synchronous write. We do this to detect the | |
1282 | * case where a single process is doing a stream of sync | |
1283 | * writes. No point in waiting for joiners in that case. | |
470decc6 DK |
1284 | */ |
1285 | pid = current->pid; | |
1286 | if (handle->h_sync && journal->j_last_sync_writer != pid) { | |
e07f7183 JB |
1287 | u64 commit_time, trans_time; |
1288 | ||
470decc6 | 1289 | journal->j_last_sync_writer = pid; |
e07f7183 JB |
1290 | |
1291 | spin_lock(&journal->j_state_lock); | |
1292 | commit_time = journal->j_average_commit_time; | |
1293 | spin_unlock(&journal->j_state_lock); | |
1294 | ||
1295 | trans_time = ktime_to_ns(ktime_sub(ktime_get(), | |
1296 | transaction->t_start_time)); | |
1297 | ||
30773840 TT |
1298 | commit_time = max_t(u64, commit_time, |
1299 | 1000*journal->j_min_batch_time); | |
e07f7183 | 1300 | commit_time = min_t(u64, commit_time, |
30773840 | 1301 | 1000*journal->j_max_batch_time); |
e07f7183 JB |
1302 | |
1303 | if (trans_time < commit_time) { | |
1304 | ktime_t expires = ktime_add_ns(ktime_get(), | |
1305 | commit_time); | |
1306 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1307 | schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); | |
1308 | } | |
470decc6 DK |
1309 | } |
1310 | ||
7058548c TT |
1311 | if (handle->h_sync) |
1312 | transaction->t_synchronous_commit = 1; | |
470decc6 DK |
1313 | current->journal_info = NULL; |
1314 | spin_lock(&journal->j_state_lock); | |
1315 | spin_lock(&transaction->t_handle_lock); | |
1316 | transaction->t_outstanding_credits -= handle->h_buffer_credits; | |
1317 | transaction->t_updates--; | |
1318 | if (!transaction->t_updates) { | |
1319 | wake_up(&journal->j_wait_updates); | |
1320 | if (journal->j_barrier_count) | |
1321 | wake_up(&journal->j_wait_transaction_locked); | |
1322 | } | |
1323 | ||
1324 | /* | |
1325 | * If the handle is marked SYNC, we need to set another commit | |
1326 | * going! We also want to force a commit if the current | |
1327 | * transaction is occupying too much of the log, or if the | |
1328 | * transaction is too old now. | |
1329 | */ | |
1330 | if (handle->h_sync || | |
1331 | transaction->t_outstanding_credits > | |
1332 | journal->j_max_transaction_buffers || | |
1333 | time_after_eq(jiffies, transaction->t_expires)) { | |
1334 | /* Do this even for aborted journals: an abort still | |
1335 | * completes the commit thread, it just doesn't write | |
1336 | * anything to disk. */ | |
1337 | tid_t tid = transaction->t_tid; | |
1338 | ||
1339 | spin_unlock(&transaction->t_handle_lock); | |
1340 | jbd_debug(2, "transaction too old, requesting commit for " | |
1341 | "handle %p\n", handle); | |
1342 | /* This is non-blocking */ | |
f7f4bccb | 1343 | __jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
1344 | spin_unlock(&journal->j_state_lock); |
1345 | ||
1346 | /* | |
f7f4bccb | 1347 | * Special case: JBD2_SYNC synchronous updates require us |
470decc6 DK |
1348 | * to wait for the commit to complete. |
1349 | */ | |
1350 | if (handle->h_sync && !(current->flags & PF_MEMALLOC)) | |
f7f4bccb | 1351 | err = jbd2_log_wait_commit(journal, tid); |
470decc6 DK |
1352 | } else { |
1353 | spin_unlock(&transaction->t_handle_lock); | |
1354 | spin_unlock(&journal->j_state_lock); | |
1355 | } | |
1356 | ||
3295f0ef | 1357 | lock_map_release(&handle->h_lockdep_map); |
7b751066 | 1358 | |
af1e76d6 | 1359 | jbd2_free_handle(handle); |
470decc6 DK |
1360 | return err; |
1361 | } | |
1362 | ||
5648ba5b RD |
1363 | /** |
1364 | * int jbd2_journal_force_commit() - force any uncommitted transactions | |
470decc6 DK |
1365 | * @journal: journal to force |
1366 | * | |
1367 | * For synchronous operations: force any uncommitted transactions | |
1368 | * to disk. May seem kludgy, but it reuses all the handle batching | |
1369 | * code in a very simple manner. | |
1370 | */ | |
f7f4bccb | 1371 | int jbd2_journal_force_commit(journal_t *journal) |
470decc6 DK |
1372 | { |
1373 | handle_t *handle; | |
1374 | int ret; | |
1375 | ||
f7f4bccb | 1376 | handle = jbd2_journal_start(journal, 1); |
470decc6 DK |
1377 | if (IS_ERR(handle)) { |
1378 | ret = PTR_ERR(handle); | |
1379 | } else { | |
1380 | handle->h_sync = 1; | |
f7f4bccb | 1381 | ret = jbd2_journal_stop(handle); |
470decc6 DK |
1382 | } |
1383 | return ret; | |
1384 | } | |
1385 | ||
1386 | /* | |
1387 | * | |
1388 | * List management code snippets: various functions for manipulating the | |
1389 | * transaction buffer lists. | |
1390 | * | |
1391 | */ | |
1392 | ||
1393 | /* | |
1394 | * Append a buffer to a transaction list, given the transaction's list head | |
1395 | * pointer. | |
1396 | * | |
1397 | * j_list_lock is held. | |
1398 | * | |
1399 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1400 | */ | |
1401 | ||
1402 | static inline void | |
1403 | __blist_add_buffer(struct journal_head **list, struct journal_head *jh) | |
1404 | { | |
1405 | if (!*list) { | |
1406 | jh->b_tnext = jh->b_tprev = jh; | |
1407 | *list = jh; | |
1408 | } else { | |
1409 | /* Insert at the tail of the list to preserve order */ | |
1410 | struct journal_head *first = *list, *last = first->b_tprev; | |
1411 | jh->b_tprev = last; | |
1412 | jh->b_tnext = first; | |
1413 | last->b_tnext = first->b_tprev = jh; | |
1414 | } | |
1415 | } | |
1416 | ||
1417 | /* | |
1418 | * Remove a buffer from a transaction list, given the transaction's list | |
1419 | * head pointer. | |
1420 | * | |
1421 | * Called with j_list_lock held, and the journal may not be locked. | |
1422 | * | |
1423 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1424 | */ | |
1425 | ||
1426 | static inline void | |
1427 | __blist_del_buffer(struct journal_head **list, struct journal_head *jh) | |
1428 | { | |
1429 | if (*list == jh) { | |
1430 | *list = jh->b_tnext; | |
1431 | if (*list == jh) | |
1432 | *list = NULL; | |
1433 | } | |
1434 | jh->b_tprev->b_tnext = jh->b_tnext; | |
1435 | jh->b_tnext->b_tprev = jh->b_tprev; | |
1436 | } | |
1437 | ||
1438 | /* | |
1439 | * Remove a buffer from the appropriate transaction list. | |
1440 | * | |
1441 | * Note that this function can *change* the value of | |
87c89c23 JK |
1442 | * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list, |
1443 | * t_log_list or t_reserved_list. If the caller is holding onto a copy of one | |
1444 | * of these pointers, it could go bad. Generally the caller needs to re-read | |
1445 | * the pointer from the transaction_t. | |
470decc6 DK |
1446 | * |
1447 | * Called under j_list_lock. The journal may not be locked. | |
1448 | */ | |
f7f4bccb | 1449 | void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
470decc6 DK |
1450 | { |
1451 | struct journal_head **list = NULL; | |
1452 | transaction_t *transaction; | |
1453 | struct buffer_head *bh = jh2bh(jh); | |
1454 | ||
1455 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1456 | transaction = jh->b_transaction; | |
1457 | if (transaction) | |
1458 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1459 | ||
1460 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1461 | if (jh->b_jlist != BJ_None) | |
4019191b | 1462 | J_ASSERT_JH(jh, transaction != NULL); |
470decc6 DK |
1463 | |
1464 | switch (jh->b_jlist) { | |
1465 | case BJ_None: | |
1466 | return; | |
470decc6 DK |
1467 | case BJ_Metadata: |
1468 | transaction->t_nr_buffers--; | |
1469 | J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); | |
1470 | list = &transaction->t_buffers; | |
1471 | break; | |
1472 | case BJ_Forget: | |
1473 | list = &transaction->t_forget; | |
1474 | break; | |
1475 | case BJ_IO: | |
1476 | list = &transaction->t_iobuf_list; | |
1477 | break; | |
1478 | case BJ_Shadow: | |
1479 | list = &transaction->t_shadow_list; | |
1480 | break; | |
1481 | case BJ_LogCtl: | |
1482 | list = &transaction->t_log_list; | |
1483 | break; | |
1484 | case BJ_Reserved: | |
1485 | list = &transaction->t_reserved_list; | |
1486 | break; | |
470decc6 DK |
1487 | } |
1488 | ||
1489 | __blist_del_buffer(list, jh); | |
1490 | jh->b_jlist = BJ_None; | |
1491 | if (test_clear_buffer_jbddirty(bh)) | |
1492 | mark_buffer_dirty(bh); /* Expose it to the VM */ | |
1493 | } | |
1494 | ||
f7f4bccb | 1495 | void __jbd2_journal_unfile_buffer(struct journal_head *jh) |
470decc6 | 1496 | { |
f7f4bccb | 1497 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
1498 | jh->b_transaction = NULL; |
1499 | } | |
1500 | ||
f7f4bccb | 1501 | void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
1502 | { |
1503 | jbd_lock_bh_state(jh2bh(jh)); | |
1504 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 1505 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1506 | spin_unlock(&journal->j_list_lock); |
1507 | jbd_unlock_bh_state(jh2bh(jh)); | |
1508 | } | |
1509 | ||
1510 | /* | |
f7f4bccb | 1511 | * Called from jbd2_journal_try_to_free_buffers(). |
470decc6 DK |
1512 | * |
1513 | * Called under jbd_lock_bh_state(bh) | |
1514 | */ | |
1515 | static void | |
1516 | __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) | |
1517 | { | |
1518 | struct journal_head *jh; | |
1519 | ||
1520 | jh = bh2jh(bh); | |
1521 | ||
1522 | if (buffer_locked(bh) || buffer_dirty(bh)) | |
1523 | goto out; | |
1524 | ||
4019191b | 1525 | if (jh->b_next_transaction != NULL) |
470decc6 DK |
1526 | goto out; |
1527 | ||
1528 | spin_lock(&journal->j_list_lock); | |
87c89c23 | 1529 | if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) { |
470decc6 DK |
1530 | /* written-back checkpointed metadata buffer */ |
1531 | if (jh->b_jlist == BJ_None) { | |
1532 | JBUFFER_TRACE(jh, "remove from checkpoint list"); | |
f7f4bccb MC |
1533 | __jbd2_journal_remove_checkpoint(jh); |
1534 | jbd2_journal_remove_journal_head(bh); | |
470decc6 DK |
1535 | __brelse(bh); |
1536 | } | |
1537 | } | |
1538 | spin_unlock(&journal->j_list_lock); | |
1539 | out: | |
1540 | return; | |
1541 | } | |
1542 | ||
470decc6 | 1543 | /** |
f7f4bccb | 1544 | * int jbd2_journal_try_to_free_buffers() - try to free page buffers. |
470decc6 DK |
1545 | * @journal: journal for operation |
1546 | * @page: to try and free | |
530576bb MC |
1547 | * @gfp_mask: we use the mask to detect how hard should we try to release |
1548 | * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to | |
1549 | * release the buffers. | |
470decc6 DK |
1550 | * |
1551 | * | |
1552 | * For all the buffers on this page, | |
1553 | * if they are fully written out ordered data, move them onto BUF_CLEAN | |
1554 | * so try_to_free_buffers() can reap them. | |
1555 | * | |
1556 | * This function returns non-zero if we wish try_to_free_buffers() | |
1557 | * to be called. We do this if the page is releasable by try_to_free_buffers(). | |
1558 | * We also do it if the page has locked or dirty buffers and the caller wants | |
1559 | * us to perform sync or async writeout. | |
1560 | * | |
1561 | * This complicates JBD locking somewhat. We aren't protected by the | |
1562 | * BKL here. We wish to remove the buffer from its committing or | |
f7f4bccb | 1563 | * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
470decc6 DK |
1564 | * |
1565 | * This may *change* the value of transaction_t->t_datalist, so anyone | |
1566 | * who looks at t_datalist needs to lock against this function. | |
1567 | * | |
f7f4bccb MC |
1568 | * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
1569 | * buffer. So we need to lock against that. jbd2_journal_dirty_data() | |
470decc6 DK |
1570 | * will come out of the lock with the buffer dirty, which makes it |
1571 | * ineligible for release here. | |
1572 | * | |
1573 | * Who else is affected by this? hmm... Really the only contender | |
1574 | * is do_get_write_access() - it could be looking at the buffer while | |
1575 | * journal_try_to_free_buffer() is changing its state. But that | |
1576 | * cannot happen because we never reallocate freed data as metadata | |
1577 | * while the data is part of a transaction. Yes? | |
530576bb MC |
1578 | * |
1579 | * Return 0 on failure, 1 on success | |
470decc6 | 1580 | */ |
f7f4bccb | 1581 | int jbd2_journal_try_to_free_buffers(journal_t *journal, |
530576bb | 1582 | struct page *page, gfp_t gfp_mask) |
470decc6 DK |
1583 | { |
1584 | struct buffer_head *head; | |
1585 | struct buffer_head *bh; | |
1586 | int ret = 0; | |
1587 | ||
1588 | J_ASSERT(PageLocked(page)); | |
1589 | ||
1590 | head = page_buffers(page); | |
1591 | bh = head; | |
1592 | do { | |
1593 | struct journal_head *jh; | |
1594 | ||
1595 | /* | |
1596 | * We take our own ref against the journal_head here to avoid | |
1597 | * having to add tons of locking around each instance of | |
530576bb MC |
1598 | * jbd2_journal_remove_journal_head() and |
1599 | * jbd2_journal_put_journal_head(). | |
470decc6 | 1600 | */ |
f7f4bccb | 1601 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1602 | if (!jh) |
1603 | continue; | |
1604 | ||
1605 | jbd_lock_bh_state(bh); | |
1606 | __journal_try_to_free_buffer(journal, bh); | |
f7f4bccb | 1607 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1608 | jbd_unlock_bh_state(bh); |
1609 | if (buffer_jbd(bh)) | |
1610 | goto busy; | |
1611 | } while ((bh = bh->b_this_page) != head); | |
530576bb | 1612 | |
470decc6 | 1613 | ret = try_to_free_buffers(page); |
530576bb | 1614 | |
470decc6 DK |
1615 | busy: |
1616 | return ret; | |
1617 | } | |
1618 | ||
1619 | /* | |
1620 | * This buffer is no longer needed. If it is on an older transaction's | |
1621 | * checkpoint list we need to record it on this transaction's forget list | |
1622 | * to pin this buffer (and hence its checkpointing transaction) down until | |
1623 | * this transaction commits. If the buffer isn't on a checkpoint list, we | |
1624 | * release it. | |
1625 | * Returns non-zero if JBD no longer has an interest in the buffer. | |
1626 | * | |
1627 | * Called under j_list_lock. | |
1628 | * | |
1629 | * Called under jbd_lock_bh_state(bh). | |
1630 | */ | |
1631 | static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) | |
1632 | { | |
1633 | int may_free = 1; | |
1634 | struct buffer_head *bh = jh2bh(jh); | |
1635 | ||
f7f4bccb | 1636 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1637 | |
1638 | if (jh->b_cp_transaction) { | |
1639 | JBUFFER_TRACE(jh, "on running+cp transaction"); | |
f91d1d04 JK |
1640 | /* |
1641 | * We don't want to write the buffer anymore, clear the | |
1642 | * bit so that we don't confuse checks in | |
1643 | * __journal_file_buffer | |
1644 | */ | |
1645 | clear_buffer_dirty(bh); | |
f7f4bccb | 1646 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
470decc6 DK |
1647 | may_free = 0; |
1648 | } else { | |
1649 | JBUFFER_TRACE(jh, "on running transaction"); | |
f7f4bccb | 1650 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
1651 | __brelse(bh); |
1652 | } | |
1653 | return may_free; | |
1654 | } | |
1655 | ||
1656 | /* | |
f7f4bccb | 1657 | * jbd2_journal_invalidatepage |
470decc6 DK |
1658 | * |
1659 | * This code is tricky. It has a number of cases to deal with. | |
1660 | * | |
1661 | * There are two invariants which this code relies on: | |
1662 | * | |
1663 | * i_size must be updated on disk before we start calling invalidatepage on the | |
1664 | * data. | |
1665 | * | |
1666 | * This is done in ext3 by defining an ext3_setattr method which | |
1667 | * updates i_size before truncate gets going. By maintaining this | |
1668 | * invariant, we can be sure that it is safe to throw away any buffers | |
1669 | * attached to the current transaction: once the transaction commits, | |
1670 | * we know that the data will not be needed. | |
1671 | * | |
1672 | * Note however that we can *not* throw away data belonging to the | |
1673 | * previous, committing transaction! | |
1674 | * | |
1675 | * Any disk blocks which *are* part of the previous, committing | |
1676 | * transaction (and which therefore cannot be discarded immediately) are | |
1677 | * not going to be reused in the new running transaction | |
1678 | * | |
1679 | * The bitmap committed_data images guarantee this: any block which is | |
1680 | * allocated in one transaction and removed in the next will be marked | |
1681 | * as in-use in the committed_data bitmap, so cannot be reused until | |
1682 | * the next transaction to delete the block commits. This means that | |
1683 | * leaving committing buffers dirty is quite safe: the disk blocks | |
1684 | * cannot be reallocated to a different file and so buffer aliasing is | |
1685 | * not possible. | |
1686 | * | |
1687 | * | |
1688 | * The above applies mainly to ordered data mode. In writeback mode we | |
1689 | * don't make guarantees about the order in which data hits disk --- in | |
1690 | * particular we don't guarantee that new dirty data is flushed before | |
1691 | * transaction commit --- so it is always safe just to discard data | |
1692 | * immediately in that mode. --sct | |
1693 | */ | |
1694 | ||
1695 | /* | |
1696 | * The journal_unmap_buffer helper function returns zero if the buffer | |
1697 | * concerned remains pinned as an anonymous buffer belonging to an older | |
1698 | * transaction. | |
1699 | * | |
1700 | * We're outside-transaction here. Either or both of j_running_transaction | |
1701 | * and j_committing_transaction may be NULL. | |
1702 | */ | |
1703 | static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh) | |
1704 | { | |
1705 | transaction_t *transaction; | |
1706 | struct journal_head *jh; | |
1707 | int may_free = 1; | |
1708 | int ret; | |
1709 | ||
1710 | BUFFER_TRACE(bh, "entry"); | |
1711 | ||
1712 | /* | |
1713 | * It is safe to proceed here without the j_list_lock because the | |
1714 | * buffers cannot be stolen by try_to_free_buffers as long as we are | |
1715 | * holding the page lock. --sct | |
1716 | */ | |
1717 | ||
1718 | if (!buffer_jbd(bh)) | |
1719 | goto zap_buffer_unlocked; | |
1720 | ||
87c89c23 | 1721 | /* OK, we have data buffer in journaled mode */ |
470decc6 DK |
1722 | spin_lock(&journal->j_state_lock); |
1723 | jbd_lock_bh_state(bh); | |
1724 | spin_lock(&journal->j_list_lock); | |
1725 | ||
f7f4bccb | 1726 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
1727 | if (!jh) |
1728 | goto zap_buffer_no_jh; | |
1729 | ||
1730 | transaction = jh->b_transaction; | |
1731 | if (transaction == NULL) { | |
1732 | /* First case: not on any transaction. If it | |
1733 | * has no checkpoint link, then we can zap it: | |
1734 | * it's a writeback-mode buffer so we don't care | |
1735 | * if it hits disk safely. */ | |
1736 | if (!jh->b_cp_transaction) { | |
1737 | JBUFFER_TRACE(jh, "not on any transaction: zap"); | |
1738 | goto zap_buffer; | |
1739 | } | |
1740 | ||
1741 | if (!buffer_dirty(bh)) { | |
1742 | /* bdflush has written it. We can drop it now */ | |
1743 | goto zap_buffer; | |
1744 | } | |
1745 | ||
1746 | /* OK, it must be in the journal but still not | |
1747 | * written fully to disk: it's metadata or | |
1748 | * journaled data... */ | |
1749 | ||
1750 | if (journal->j_running_transaction) { | |
1751 | /* ... and once the current transaction has | |
1752 | * committed, the buffer won't be needed any | |
1753 | * longer. */ | |
1754 | JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); | |
1755 | ret = __dispose_buffer(jh, | |
1756 | journal->j_running_transaction); | |
f7f4bccb | 1757 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1758 | spin_unlock(&journal->j_list_lock); |
1759 | jbd_unlock_bh_state(bh); | |
1760 | spin_unlock(&journal->j_state_lock); | |
1761 | return ret; | |
1762 | } else { | |
1763 | /* There is no currently-running transaction. So the | |
1764 | * orphan record which we wrote for this file must have | |
1765 | * passed into commit. We must attach this buffer to | |
1766 | * the committing transaction, if it exists. */ | |
1767 | if (journal->j_committing_transaction) { | |
1768 | JBUFFER_TRACE(jh, "give to committing trans"); | |
1769 | ret = __dispose_buffer(jh, | |
1770 | journal->j_committing_transaction); | |
f7f4bccb | 1771 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1772 | spin_unlock(&journal->j_list_lock); |
1773 | jbd_unlock_bh_state(bh); | |
1774 | spin_unlock(&journal->j_state_lock); | |
1775 | return ret; | |
1776 | } else { | |
1777 | /* The orphan record's transaction has | |
1778 | * committed. We can cleanse this buffer */ | |
1779 | clear_buffer_jbddirty(bh); | |
1780 | goto zap_buffer; | |
1781 | } | |
1782 | } | |
1783 | } else if (transaction == journal->j_committing_transaction) { | |
9b57988d | 1784 | JBUFFER_TRACE(jh, "on committing transaction"); |
470decc6 DK |
1785 | /* |
1786 | * If it is committing, we simply cannot touch it. We | |
1787 | * can remove it's next_transaction pointer from the | |
1788 | * running transaction if that is set, but nothing | |
1789 | * else. */ | |
470decc6 DK |
1790 | set_buffer_freed(bh); |
1791 | if (jh->b_next_transaction) { | |
1792 | J_ASSERT(jh->b_next_transaction == | |
1793 | journal->j_running_transaction); | |
1794 | jh->b_next_transaction = NULL; | |
1795 | } | |
f7f4bccb | 1796 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1797 | spin_unlock(&journal->j_list_lock); |
1798 | jbd_unlock_bh_state(bh); | |
1799 | spin_unlock(&journal->j_state_lock); | |
1800 | return 0; | |
1801 | } else { | |
1802 | /* Good, the buffer belongs to the running transaction. | |
1803 | * We are writing our own transaction's data, not any | |
1804 | * previous one's, so it is safe to throw it away | |
1805 | * (remember that we expect the filesystem to have set | |
1806 | * i_size already for this truncate so recovery will not | |
1807 | * expose the disk blocks we are discarding here.) */ | |
1808 | J_ASSERT_JH(jh, transaction == journal->j_running_transaction); | |
9b57988d | 1809 | JBUFFER_TRACE(jh, "on running transaction"); |
470decc6 DK |
1810 | may_free = __dispose_buffer(jh, transaction); |
1811 | } | |
1812 | ||
1813 | zap_buffer: | |
f7f4bccb | 1814 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1815 | zap_buffer_no_jh: |
1816 | spin_unlock(&journal->j_list_lock); | |
1817 | jbd_unlock_bh_state(bh); | |
1818 | spin_unlock(&journal->j_state_lock); | |
1819 | zap_buffer_unlocked: | |
1820 | clear_buffer_dirty(bh); | |
1821 | J_ASSERT_BH(bh, !buffer_jbddirty(bh)); | |
1822 | clear_buffer_mapped(bh); | |
1823 | clear_buffer_req(bh); | |
1824 | clear_buffer_new(bh); | |
1825 | bh->b_bdev = NULL; | |
1826 | return may_free; | |
1827 | } | |
1828 | ||
1829 | /** | |
f7f4bccb | 1830 | * void jbd2_journal_invalidatepage() |
470decc6 DK |
1831 | * @journal: journal to use for flush... |
1832 | * @page: page to flush | |
1833 | * @offset: length of page to invalidate. | |
1834 | * | |
1835 | * Reap page buffers containing data after offset in page. | |
1836 | * | |
1837 | */ | |
f7f4bccb | 1838 | void jbd2_journal_invalidatepage(journal_t *journal, |
470decc6 DK |
1839 | struct page *page, |
1840 | unsigned long offset) | |
1841 | { | |
1842 | struct buffer_head *head, *bh, *next; | |
1843 | unsigned int curr_off = 0; | |
1844 | int may_free = 1; | |
1845 | ||
1846 | if (!PageLocked(page)) | |
1847 | BUG(); | |
1848 | if (!page_has_buffers(page)) | |
1849 | return; | |
1850 | ||
1851 | /* We will potentially be playing with lists other than just the | |
1852 | * data lists (especially for journaled data mode), so be | |
1853 | * cautious in our locking. */ | |
1854 | ||
1855 | head = bh = page_buffers(page); | |
1856 | do { | |
1857 | unsigned int next_off = curr_off + bh->b_size; | |
1858 | next = bh->b_this_page; | |
1859 | ||
1860 | if (offset <= curr_off) { | |
1861 | /* This block is wholly outside the truncation point */ | |
1862 | lock_buffer(bh); | |
1863 | may_free &= journal_unmap_buffer(journal, bh); | |
1864 | unlock_buffer(bh); | |
1865 | } | |
1866 | curr_off = next_off; | |
1867 | bh = next; | |
1868 | ||
1869 | } while (bh != head); | |
1870 | ||
1871 | if (!offset) { | |
1872 | if (may_free && try_to_free_buffers(page)) | |
1873 | J_ASSERT(!page_has_buffers(page)); | |
1874 | } | |
1875 | } | |
1876 | ||
1877 | /* | |
1878 | * File a buffer on the given transaction list. | |
1879 | */ | |
f7f4bccb | 1880 | void __jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
1881 | transaction_t *transaction, int jlist) |
1882 | { | |
1883 | struct journal_head **list = NULL; | |
1884 | int was_dirty = 0; | |
1885 | struct buffer_head *bh = jh2bh(jh); | |
1886 | ||
1887 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1888 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1889 | ||
1890 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1891 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
4019191b | 1892 | jh->b_transaction == NULL); |
470decc6 DK |
1893 | |
1894 | if (jh->b_transaction && jh->b_jlist == jlist) | |
1895 | return; | |
1896 | ||
470decc6 DK |
1897 | if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
1898 | jlist == BJ_Shadow || jlist == BJ_Forget) { | |
f91d1d04 JK |
1899 | /* |
1900 | * For metadata buffers, we track dirty bit in buffer_jbddirty | |
1901 | * instead of buffer_dirty. We should not see a dirty bit set | |
1902 | * here because we clear it in do_get_write_access but e.g. | |
1903 | * tune2fs can modify the sb and set the dirty bit at any time | |
1904 | * so we try to gracefully handle that. | |
1905 | */ | |
1906 | if (buffer_dirty(bh)) | |
1907 | warn_dirty_buffer(bh); | |
470decc6 DK |
1908 | if (test_clear_buffer_dirty(bh) || |
1909 | test_clear_buffer_jbddirty(bh)) | |
1910 | was_dirty = 1; | |
1911 | } | |
1912 | ||
1913 | if (jh->b_transaction) | |
f7f4bccb | 1914 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
1915 | jh->b_transaction = transaction; |
1916 | ||
1917 | switch (jlist) { | |
1918 | case BJ_None: | |
1919 | J_ASSERT_JH(jh, !jh->b_committed_data); | |
1920 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
1921 | return; | |
470decc6 DK |
1922 | case BJ_Metadata: |
1923 | transaction->t_nr_buffers++; | |
1924 | list = &transaction->t_buffers; | |
1925 | break; | |
1926 | case BJ_Forget: | |
1927 | list = &transaction->t_forget; | |
1928 | break; | |
1929 | case BJ_IO: | |
1930 | list = &transaction->t_iobuf_list; | |
1931 | break; | |
1932 | case BJ_Shadow: | |
1933 | list = &transaction->t_shadow_list; | |
1934 | break; | |
1935 | case BJ_LogCtl: | |
1936 | list = &transaction->t_log_list; | |
1937 | break; | |
1938 | case BJ_Reserved: | |
1939 | list = &transaction->t_reserved_list; | |
1940 | break; | |
470decc6 DK |
1941 | } |
1942 | ||
1943 | __blist_add_buffer(list, jh); | |
1944 | jh->b_jlist = jlist; | |
1945 | ||
1946 | if (was_dirty) | |
1947 | set_buffer_jbddirty(bh); | |
1948 | } | |
1949 | ||
f7f4bccb | 1950 | void jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
1951 | transaction_t *transaction, int jlist) |
1952 | { | |
1953 | jbd_lock_bh_state(jh2bh(jh)); | |
1954 | spin_lock(&transaction->t_journal->j_list_lock); | |
f7f4bccb | 1955 | __jbd2_journal_file_buffer(jh, transaction, jlist); |
470decc6 DK |
1956 | spin_unlock(&transaction->t_journal->j_list_lock); |
1957 | jbd_unlock_bh_state(jh2bh(jh)); | |
1958 | } | |
1959 | ||
1960 | /* | |
1961 | * Remove a buffer from its current buffer list in preparation for | |
1962 | * dropping it from its current transaction entirely. If the buffer has | |
1963 | * already started to be used by a subsequent transaction, refile the | |
1964 | * buffer on that transaction's metadata list. | |
1965 | * | |
1966 | * Called under journal->j_list_lock | |
1967 | * | |
1968 | * Called under jbd_lock_bh_state(jh2bh(jh)) | |
1969 | */ | |
f7f4bccb | 1970 | void __jbd2_journal_refile_buffer(struct journal_head *jh) |
470decc6 DK |
1971 | { |
1972 | int was_dirty; | |
1973 | struct buffer_head *bh = jh2bh(jh); | |
1974 | ||
1975 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1976 | if (jh->b_transaction) | |
1977 | assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); | |
1978 | ||
1979 | /* If the buffer is now unused, just drop it. */ | |
1980 | if (jh->b_next_transaction == NULL) { | |
f7f4bccb | 1981 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1982 | return; |
1983 | } | |
1984 | ||
1985 | /* | |
1986 | * It has been modified by a later transaction: add it to the new | |
1987 | * transaction's metadata list. | |
1988 | */ | |
1989 | ||
1990 | was_dirty = test_clear_buffer_jbddirty(bh); | |
f7f4bccb | 1991 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
1992 | jh->b_transaction = jh->b_next_transaction; |
1993 | jh->b_next_transaction = NULL; | |
f7f4bccb | 1994 | __jbd2_journal_file_buffer(jh, jh->b_transaction, |
1dfc3220 | 1995 | jh->b_modified ? BJ_Metadata : BJ_Reserved); |
470decc6 DK |
1996 | J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
1997 | ||
1998 | if (was_dirty) | |
1999 | set_buffer_jbddirty(bh); | |
2000 | } | |
2001 | ||
2002 | /* | |
2003 | * For the unlocked version of this call, also make sure that any | |
2004 | * hanging journal_head is cleaned up if necessary. | |
2005 | * | |
f7f4bccb | 2006 | * __jbd2_journal_refile_buffer is usually called as part of a single locked |
470decc6 DK |
2007 | * operation on a buffer_head, in which the caller is probably going to |
2008 | * be hooking the journal_head onto other lists. In that case it is up | |
2009 | * to the caller to remove the journal_head if necessary. For the | |
f7f4bccb | 2010 | * unlocked jbd2_journal_refile_buffer call, the caller isn't going to be |
470decc6 DK |
2011 | * doing anything else to the buffer so we need to do the cleanup |
2012 | * ourselves to avoid a jh leak. | |
2013 | * | |
2014 | * *** The journal_head may be freed by this call! *** | |
2015 | */ | |
f7f4bccb | 2016 | void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
2017 | { |
2018 | struct buffer_head *bh = jh2bh(jh); | |
2019 | ||
2020 | jbd_lock_bh_state(bh); | |
2021 | spin_lock(&journal->j_list_lock); | |
2022 | ||
f7f4bccb | 2023 | __jbd2_journal_refile_buffer(jh); |
470decc6 | 2024 | jbd_unlock_bh_state(bh); |
f7f4bccb | 2025 | jbd2_journal_remove_journal_head(bh); |
470decc6 DK |
2026 | |
2027 | spin_unlock(&journal->j_list_lock); | |
2028 | __brelse(bh); | |
2029 | } | |
c851ed54 JK |
2030 | |
2031 | /* | |
2032 | * File inode in the inode list of the handle's transaction | |
2033 | */ | |
2034 | int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode) | |
2035 | { | |
2036 | transaction_t *transaction = handle->h_transaction; | |
2037 | journal_t *journal = transaction->t_journal; | |
2038 | ||
2039 | if (is_handle_aborted(handle)) | |
2040 | return -EIO; | |
2041 | ||
2042 | jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, | |
2043 | transaction->t_tid); | |
2044 | ||
2045 | /* | |
2046 | * First check whether inode isn't already on the transaction's | |
2047 | * lists without taking the lock. Note that this check is safe | |
2048 | * without the lock as we cannot race with somebody removing inode | |
2049 | * from the transaction. The reason is that we remove inode from the | |
2050 | * transaction only in journal_release_jbd_inode() and when we commit | |
2051 | * the transaction. We are guarded from the first case by holding | |
2052 | * a reference to the inode. We are safe against the second case | |
2053 | * because if jinode->i_transaction == transaction, commit code | |
2054 | * cannot touch the transaction because we hold reference to it, | |
2055 | * and if jinode->i_next_transaction == transaction, commit code | |
2056 | * will only file the inode where we want it. | |
2057 | */ | |
2058 | if (jinode->i_transaction == transaction || | |
2059 | jinode->i_next_transaction == transaction) | |
2060 | return 0; | |
2061 | ||
2062 | spin_lock(&journal->j_list_lock); | |
2063 | ||
2064 | if (jinode->i_transaction == transaction || | |
2065 | jinode->i_next_transaction == transaction) | |
2066 | goto done; | |
2067 | ||
2068 | /* On some different transaction's list - should be | |
2069 | * the committing one */ | |
2070 | if (jinode->i_transaction) { | |
2071 | J_ASSERT(jinode->i_next_transaction == NULL); | |
2072 | J_ASSERT(jinode->i_transaction == | |
2073 | journal->j_committing_transaction); | |
2074 | jinode->i_next_transaction = transaction; | |
2075 | goto done; | |
2076 | } | |
2077 | /* Not on any transaction list... */ | |
2078 | J_ASSERT(!jinode->i_next_transaction); | |
2079 | jinode->i_transaction = transaction; | |
2080 | list_add(&jinode->i_list, &transaction->t_inode_list); | |
2081 | done: | |
2082 | spin_unlock(&journal->j_list_lock); | |
2083 | ||
2084 | return 0; | |
2085 | } | |
2086 | ||
2087 | /* | |
7f5aa215 JK |
2088 | * File truncate and transaction commit interact with each other in a |
2089 | * non-trivial way. If a transaction writing data block A is | |
2090 | * committing, we cannot discard the data by truncate until we have | |
2091 | * written them. Otherwise if we crashed after the transaction with | |
2092 | * write has committed but before the transaction with truncate has | |
2093 | * committed, we could see stale data in block A. This function is a | |
2094 | * helper to solve this problem. It starts writeout of the truncated | |
2095 | * part in case it is in the committing transaction. | |
2096 | * | |
2097 | * Filesystem code must call this function when inode is journaled in | |
2098 | * ordered mode before truncation happens and after the inode has been | |
2099 | * placed on orphan list with the new inode size. The second condition | |
2100 | * avoids the race that someone writes new data and we start | |
2101 | * committing the transaction after this function has been called but | |
2102 | * before a transaction for truncate is started (and furthermore it | |
2103 | * allows us to optimize the case where the addition to orphan list | |
2104 | * happens in the same transaction as write --- we don't have to write | |
2105 | * any data in such case). | |
c851ed54 | 2106 | */ |
7f5aa215 JK |
2107 | int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
2108 | struct jbd2_inode *jinode, | |
c851ed54 JK |
2109 | loff_t new_size) |
2110 | { | |
7f5aa215 | 2111 | transaction_t *inode_trans, *commit_trans; |
c851ed54 JK |
2112 | int ret = 0; |
2113 | ||
7f5aa215 JK |
2114 | /* This is a quick check to avoid locking if not necessary */ |
2115 | if (!jinode->i_transaction) | |
c851ed54 | 2116 | goto out; |
7f5aa215 JK |
2117 | /* Locks are here just to force reading of recent values, it is |
2118 | * enough that the transaction was not committing before we started | |
2119 | * a transaction adding the inode to orphan list */ | |
c851ed54 JK |
2120 | spin_lock(&journal->j_state_lock); |
2121 | commit_trans = journal->j_committing_transaction; | |
2122 | spin_unlock(&journal->j_state_lock); | |
7f5aa215 JK |
2123 | spin_lock(&journal->j_list_lock); |
2124 | inode_trans = jinode->i_transaction; | |
2125 | spin_unlock(&journal->j_list_lock); | |
2126 | if (inode_trans == commit_trans) { | |
2127 | ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, | |
c851ed54 JK |
2128 | new_size, LLONG_MAX); |
2129 | if (ret) | |
2130 | jbd2_journal_abort(journal, ret); | |
2131 | } | |
2132 | out: | |
2133 | return ret; | |
2134 | } |