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f5166768 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
470decc6 | 2 | /* |
58862699 | 3 | * linux/fs/jbd2/transaction.c |
470decc6 DK |
4 | * |
5 | * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 | |
6 | * | |
7 | * Copyright 1998 Red Hat corp --- All Rights Reserved | |
8 | * | |
470decc6 DK |
9 | * Generic filesystem transaction handling code; part of the ext2fs |
10 | * journaling system. | |
11 | * | |
12 | * This file manages transactions (compound commits managed by the | |
13 | * journaling code) and handles (individual atomic operations by the | |
14 | * filesystem). | |
15 | */ | |
16 | ||
17 | #include <linux/time.h> | |
18 | #include <linux/fs.h> | |
f7f4bccb | 19 | #include <linux/jbd2.h> |
470decc6 DK |
20 | #include <linux/errno.h> |
21 | #include <linux/slab.h> | |
22 | #include <linux/timer.h> | |
470decc6 DK |
23 | #include <linux/mm.h> |
24 | #include <linux/highmem.h> | |
e07f7183 | 25 | #include <linux/hrtimer.h> |
47def826 | 26 | #include <linux/backing-dev.h> |
44705754 | 27 | #include <linux/bug.h> |
47def826 | 28 | #include <linux/module.h> |
81378da6 | 29 | #include <linux/sched/mm.h> |
470decc6 | 30 | |
343d9c28 TT |
31 | #include <trace/events/jbd2.h> |
32 | ||
7ddae860 | 33 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
de1b7941 | 34 | static void __jbd2_journal_unfile_buffer(struct journal_head *jh); |
7ddae860 | 35 | |
0c2022ec YY |
36 | static struct kmem_cache *transaction_cache; |
37 | int __init jbd2_journal_init_transaction_cache(void) | |
38 | { | |
39 | J_ASSERT(!transaction_cache); | |
40 | transaction_cache = kmem_cache_create("jbd2_transaction_s", | |
41 | sizeof(transaction_t), | |
42 | 0, | |
43 | SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY, | |
44 | NULL); | |
0d52154b CX |
45 | if (!transaction_cache) { |
46 | pr_emerg("JBD2: failed to create transaction cache\n"); | |
47 | return -ENOMEM; | |
48 | } | |
49 | return 0; | |
0c2022ec YY |
50 | } |
51 | ||
52 | void jbd2_journal_destroy_transaction_cache(void) | |
53 | { | |
8bdd5b60 WL |
54 | kmem_cache_destroy(transaction_cache); |
55 | transaction_cache = NULL; | |
0c2022ec YY |
56 | } |
57 | ||
58 | void jbd2_journal_free_transaction(transaction_t *transaction) | |
59 | { | |
60 | if (unlikely(ZERO_OR_NULL_PTR(transaction))) | |
61 | return; | |
62 | kmem_cache_free(transaction_cache, transaction); | |
63 | } | |
64 | ||
9f356e5a | 65 | /* |
19014d69 | 66 | * Base amount of descriptor blocks we reserve for each transaction. |
9f356e5a | 67 | */ |
9f356e5a JK |
68 | static int jbd2_descriptor_blocks_per_trans(journal_t *journal) |
69 | { | |
19014d69 JK |
70 | int tag_space = journal->j_blocksize - sizeof(journal_header_t); |
71 | int tags_per_block; | |
72 | ||
73 | /* Subtract UUID */ | |
74 | tag_space -= 16; | |
75 | if (jbd2_journal_has_csum_v2or3(journal)) | |
76 | tag_space -= sizeof(struct jbd2_journal_block_tail); | |
77 | /* Commit code leaves a slack space of 16 bytes at the end of block */ | |
78 | tags_per_block = (tag_space - 16) / journal_tag_bytes(journal); | |
79 | /* | |
80 | * Revoke descriptors are accounted separately so we need to reserve | |
81 | * space for commit block and normal transaction descriptor blocks. | |
82 | */ | |
83 | return 1 + DIV_ROUND_UP(journal->j_max_transaction_buffers, | |
84 | tags_per_block); | |
9f356e5a JK |
85 | } |
86 | ||
470decc6 | 87 | /* |
f7f4bccb | 88 | * jbd2_get_transaction: obtain a new transaction_t object. |
470decc6 | 89 | * |
0df6f469 | 90 | * Simply initialise a new transaction. Initialize it in |
470decc6 DK |
91 | * RUNNING state and add it to the current journal (which should not |
92 | * have an existing running transaction: we only make a new transaction | |
93 | * once we have started to commit the old one). | |
94 | * | |
95 | * Preconditions: | |
96 | * The journal MUST be locked. We don't perform atomic mallocs on the | |
97 | * new transaction and we can't block without protecting against other | |
98 | * processes trying to touch the journal while it is in transition. | |
99 | * | |
470decc6 DK |
100 | */ |
101 | ||
0df6f469 LS |
102 | static void jbd2_get_transaction(journal_t *journal, |
103 | transaction_t *transaction) | |
470decc6 DK |
104 | { |
105 | transaction->t_journal = journal; | |
106 | transaction->t_state = T_RUNNING; | |
e07f7183 | 107 | transaction->t_start_time = ktime_get(); |
470decc6 DK |
108 | transaction->t_tid = journal->j_transaction_sequence++; |
109 | transaction->t_expires = jiffies + journal->j_commit_interval; | |
110 | spin_lock_init(&transaction->t_handle_lock); | |
a51dca9c | 111 | atomic_set(&transaction->t_updates, 0); |
8f7d89f3 | 112 | atomic_set(&transaction->t_outstanding_credits, |
9f356e5a | 113 | jbd2_descriptor_blocks_per_trans(journal) + |
8f7d89f3 | 114 | atomic_read(&journal->j_reserved_credits)); |
fdc3ef88 | 115 | atomic_set(&transaction->t_outstanding_revokes, 0); |
8dd42046 | 116 | atomic_set(&transaction->t_handle_count, 0); |
c851ed54 | 117 | INIT_LIST_HEAD(&transaction->t_inode_list); |
3e624fc7 | 118 | INIT_LIST_HEAD(&transaction->t_private_list); |
470decc6 DK |
119 | |
120 | /* Set up the commit timer for the new transaction. */ | |
b1f485f2 | 121 | journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
470decc6 DK |
122 | add_timer(&journal->j_commit_timer); |
123 | ||
124 | J_ASSERT(journal->j_running_transaction == NULL); | |
125 | journal->j_running_transaction = transaction; | |
8e85fb3f JL |
126 | transaction->t_max_wait = 0; |
127 | transaction->t_start = jiffies; | |
9fff24aa | 128 | transaction->t_requested = 0; |
470decc6 DK |
129 | } |
130 | ||
131 | /* | |
132 | * Handle management. | |
133 | * | |
134 | * A handle_t is an object which represents a single atomic update to a | |
135 | * filesystem, and which tracks all of the modifications which form part | |
136 | * of that one update. | |
137 | */ | |
138 | ||
6d0bf005 | 139 | /* |
28e35e42 | 140 | * Update transaction's maximum wait time, if debugging is enabled. |
6d0bf005 TT |
141 | * |
142 | * In order for t_max_wait to be reliable, it must be protected by a | |
143 | * lock. But doing so will mean that start_this_handle() can not be | |
144 | * run in parallel on SMP systems, which limits our scalability. So | |
145 | * unless debugging is enabled, we no longer update t_max_wait, which | |
146 | * means that maximum wait time reported by the jbd2_run_stats | |
147 | * tracepoint will always be zero. | |
148 | */ | |
28e35e42 TM |
149 | static inline void update_t_max_wait(transaction_t *transaction, |
150 | unsigned long ts) | |
6d0bf005 TT |
151 | { |
152 | #ifdef CONFIG_JBD2_DEBUG | |
6d0bf005 TT |
153 | if (jbd2_journal_enable_debug && |
154 | time_after(transaction->t_start, ts)) { | |
155 | ts = jbd2_time_diff(ts, transaction->t_start); | |
156 | spin_lock(&transaction->t_handle_lock); | |
157 | if (ts > transaction->t_max_wait) | |
158 | transaction->t_max_wait = ts; | |
159 | spin_unlock(&transaction->t_handle_lock); | |
160 | } | |
161 | #endif | |
162 | } | |
163 | ||
8f7d89f3 | 164 | /* |
96f1e097 JK |
165 | * Wait until running transaction passes to T_FLUSH state and new transaction |
166 | * can thus be started. Also starts the commit if needed. The function expects | |
167 | * running transaction to exist and releases j_state_lock. | |
8f7d89f3 JK |
168 | */ |
169 | static void wait_transaction_locked(journal_t *journal) | |
170 | __releases(journal->j_state_lock) | |
171 | { | |
172 | DEFINE_WAIT(wait); | |
173 | int need_to_start; | |
174 | tid_t tid = journal->j_running_transaction->t_tid; | |
175 | ||
176 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, | |
177 | TASK_UNINTERRUPTIBLE); | |
178 | need_to_start = !tid_geq(journal->j_commit_request, tid); | |
179 | read_unlock(&journal->j_state_lock); | |
180 | if (need_to_start) | |
181 | jbd2_log_start_commit(journal, tid); | |
e03a9976 | 182 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 JK |
183 | schedule(); |
184 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
185 | } | |
186 | ||
96f1e097 JK |
187 | /* |
188 | * Wait until running transaction transitions from T_SWITCH to T_FLUSH | |
189 | * state and new transaction can thus be started. The function releases | |
190 | * j_state_lock. | |
191 | */ | |
192 | static void wait_transaction_switching(journal_t *journal) | |
193 | __releases(journal->j_state_lock) | |
194 | { | |
195 | DEFINE_WAIT(wait); | |
196 | ||
197 | if (WARN_ON(!journal->j_running_transaction || | |
05d5233d TT |
198 | journal->j_running_transaction->t_state != T_SWITCH)) { |
199 | read_unlock(&journal->j_state_lock); | |
96f1e097 | 200 | return; |
05d5233d | 201 | } |
96f1e097 JK |
202 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, |
203 | TASK_UNINTERRUPTIBLE); | |
204 | read_unlock(&journal->j_state_lock); | |
205 | /* | |
206 | * We don't call jbd2_might_wait_for_commit() here as there's no | |
207 | * waiting for outstanding handles happening anymore in T_SWITCH state | |
208 | * and handling of reserved handles actually relies on that for | |
209 | * correctness. | |
210 | */ | |
211 | schedule(); | |
212 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
213 | } | |
214 | ||
8f7d89f3 JK |
215 | static void sub_reserved_credits(journal_t *journal, int blocks) |
216 | { | |
217 | atomic_sub(blocks, &journal->j_reserved_credits); | |
218 | wake_up(&journal->j_wait_reserved); | |
219 | } | |
220 | ||
221 | /* | |
222 | * Wait until we can add credits for handle to the running transaction. Called | |
223 | * with j_state_lock held for reading. Returns 0 if handle joined the running | |
224 | * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and | |
225 | * caller must retry. | |
b33d9f59 TT |
226 | * |
227 | * Note: because j_state_lock may be dropped depending on the return | |
228 | * value, we need to fake out sparse so ti doesn't complain about a | |
229 | * locking imbalance. Callers of add_transaction_credits will need to | |
230 | * make a similar accomodation. | |
8f7d89f3 JK |
231 | */ |
232 | static int add_transaction_credits(journal_t *journal, int blocks, | |
233 | int rsv_blocks) | |
b33d9f59 | 234 | __must_hold(&journal->j_state_lock) |
8f7d89f3 JK |
235 | { |
236 | transaction_t *t = journal->j_running_transaction; | |
237 | int needed; | |
238 | int total = blocks + rsv_blocks; | |
239 | ||
240 | /* | |
241 | * If the current transaction is locked down for commit, wait | |
242 | * for the lock to be released. | |
243 | */ | |
96f1e097 JK |
244 | if (t->t_state != T_RUNNING) { |
245 | WARN_ON_ONCE(t->t_state >= T_FLUSH); | |
8f7d89f3 | 246 | wait_transaction_locked(journal); |
b33d9f59 | 247 | __acquire(&journal->j_state_lock); /* fake out sparse */ |
8f7d89f3 JK |
248 | return 1; |
249 | } | |
250 | ||
251 | /* | |
252 | * If there is not enough space left in the log to write all | |
253 | * potential buffers requested by this operation, we need to | |
254 | * stall pending a log checkpoint to free some more log space. | |
255 | */ | |
256 | needed = atomic_add_return(total, &t->t_outstanding_credits); | |
257 | if (needed > journal->j_max_transaction_buffers) { | |
258 | /* | |
259 | * If the current transaction is already too large, | |
260 | * then start to commit it: we can then go back and | |
261 | * attach this handle to a new transaction. | |
262 | */ | |
263 | atomic_sub(total, &t->t_outstanding_credits); | |
6d3ec14d LC |
264 | |
265 | /* | |
266 | * Is the number of reserved credits in the current transaction too | |
267 | * big to fit this handle? Wait until reserved credits are freed. | |
268 | */ | |
269 | if (atomic_read(&journal->j_reserved_credits) + total > | |
270 | journal->j_max_transaction_buffers) { | |
271 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 272 | jbd2_might_wait_for_commit(journal); |
6d3ec14d LC |
273 | wait_event(journal->j_wait_reserved, |
274 | atomic_read(&journal->j_reserved_credits) + total <= | |
275 | journal->j_max_transaction_buffers); | |
b33d9f59 | 276 | __acquire(&journal->j_state_lock); /* fake out sparse */ |
6d3ec14d LC |
277 | return 1; |
278 | } | |
279 | ||
8f7d89f3 | 280 | wait_transaction_locked(journal); |
b33d9f59 | 281 | __acquire(&journal->j_state_lock); /* fake out sparse */ |
8f7d89f3 JK |
282 | return 1; |
283 | } | |
284 | ||
285 | /* | |
286 | * The commit code assumes that it can get enough log space | |
287 | * without forcing a checkpoint. This is *critical* for | |
288 | * correctness: a checkpoint of a buffer which is also | |
289 | * associated with a committing transaction creates a deadlock, | |
290 | * so commit simply cannot force through checkpoints. | |
291 | * | |
292 | * We must therefore ensure the necessary space in the journal | |
293 | * *before* starting to dirty potentially checkpointed buffers | |
294 | * in the new transaction. | |
295 | */ | |
77444ac4 | 296 | if (jbd2_log_space_left(journal) < journal->j_max_transaction_buffers) { |
8f7d89f3 JK |
297 | atomic_sub(total, &t->t_outstanding_credits); |
298 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 299 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 | 300 | write_lock(&journal->j_state_lock); |
77444ac4 JK |
301 | if (jbd2_log_space_left(journal) < |
302 | journal->j_max_transaction_buffers) | |
8f7d89f3 JK |
303 | __jbd2_log_wait_for_space(journal); |
304 | write_unlock(&journal->j_state_lock); | |
b33d9f59 | 305 | __acquire(&journal->j_state_lock); /* fake out sparse */ |
8f7d89f3 JK |
306 | return 1; |
307 | } | |
308 | ||
309 | /* No reservation? We are done... */ | |
310 | if (!rsv_blocks) | |
311 | return 0; | |
312 | ||
313 | needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits); | |
314 | /* We allow at most half of a transaction to be reserved */ | |
315 | if (needed > journal->j_max_transaction_buffers / 2) { | |
316 | sub_reserved_credits(journal, rsv_blocks); | |
317 | atomic_sub(total, &t->t_outstanding_credits); | |
318 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 319 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 JK |
320 | wait_event(journal->j_wait_reserved, |
321 | atomic_read(&journal->j_reserved_credits) + rsv_blocks | |
322 | <= journal->j_max_transaction_buffers / 2); | |
b33d9f59 | 323 | __acquire(&journal->j_state_lock); /* fake out sparse */ |
8f7d89f3 JK |
324 | return 1; |
325 | } | |
326 | return 0; | |
327 | } | |
328 | ||
470decc6 DK |
329 | /* |
330 | * start_this_handle: Given a handle, deal with any locking or stalling | |
331 | * needed to make sure that there is enough journal space for the handle | |
332 | * to begin. Attach the handle to a transaction and set up the | |
333 | * transaction's buffer credits. | |
334 | */ | |
335 | ||
47def826 | 336 | static int start_this_handle(journal_t *journal, handle_t *handle, |
d2159fb7 | 337 | gfp_t gfp_mask) |
470decc6 | 338 | { |
e4471831 | 339 | transaction_t *transaction, *new_transaction = NULL; |
933f1c1e | 340 | int blocks = handle->h_total_credits; |
8f7d89f3 | 341 | int rsv_blocks = 0; |
28e35e42 | 342 | unsigned long ts = jiffies; |
470decc6 | 343 | |
6d3ec14d | 344 | if (handle->h_rsv_handle) |
933f1c1e | 345 | rsv_blocks = handle->h_rsv_handle->h_total_credits; |
6d3ec14d | 346 | |
8f7d89f3 | 347 | /* |
6d3ec14d LC |
348 | * Limit the number of reserved credits to 1/2 of maximum transaction |
349 | * size and limit the number of total credits to not exceed maximum | |
350 | * transaction size per operation. | |
8f7d89f3 | 351 | */ |
6d3ec14d LC |
352 | if ((rsv_blocks > journal->j_max_transaction_buffers / 2) || |
353 | (rsv_blocks + blocks > journal->j_max_transaction_buffers)) { | |
354 | printk(KERN_ERR "JBD2: %s wants too many credits " | |
355 | "credits:%d rsv_credits:%d max:%d\n", | |
356 | current->comm, blocks, rsv_blocks, | |
357 | journal->j_max_transaction_buffers); | |
358 | WARN_ON(1); | |
47def826 | 359 | return -ENOSPC; |
470decc6 DK |
360 | } |
361 | ||
362 | alloc_transaction: | |
3b1833e9 JK |
363 | /* |
364 | * This check is racy but it is just an optimization of allocating new | |
365 | * transaction early if there are high chances we'll need it. If we | |
366 | * guess wrong, we'll retry or free unused transaction. | |
367 | */ | |
368 | if (!data_race(journal->j_running_transaction)) { | |
6ccaf3e2 MH |
369 | /* |
370 | * If __GFP_FS is not present, then we may be being called from | |
371 | * inside the fs writeback layer, so we MUST NOT fail. | |
372 | */ | |
373 | if ((gfp_mask & __GFP_FS) == 0) | |
374 | gfp_mask |= __GFP_NOFAIL; | |
b2f4edb3 WG |
375 | new_transaction = kmem_cache_zalloc(transaction_cache, |
376 | gfp_mask); | |
6ccaf3e2 | 377 | if (!new_transaction) |
47def826 | 378 | return -ENOMEM; |
470decc6 DK |
379 | } |
380 | ||
381 | jbd_debug(3, "New handle %p going live.\n", handle); | |
382 | ||
470decc6 DK |
383 | /* |
384 | * We need to hold j_state_lock until t_updates has been incremented, | |
385 | * for proper journal barrier handling | |
386 | */ | |
a931da6a TT |
387 | repeat: |
388 | read_lock(&journal->j_state_lock); | |
5c2178e7 | 389 | BUG_ON(journal->j_flags & JBD2_UNMOUNT); |
470decc6 | 390 | if (is_journal_aborted(journal) || |
f7f4bccb | 391 | (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
a931da6a | 392 | read_unlock(&journal->j_state_lock); |
0c2022ec | 393 | jbd2_journal_free_transaction(new_transaction); |
47def826 | 394 | return -EROFS; |
470decc6 DK |
395 | } |
396 | ||
8f7d89f3 JK |
397 | /* |
398 | * Wait on the journal's transaction barrier if necessary. Specifically | |
399 | * we allow reserved handles to proceed because otherwise commit could | |
400 | * deadlock on page writeback not being able to complete. | |
401 | */ | |
402 | if (!handle->h_reserved && journal->j_barrier_count) { | |
a931da6a | 403 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
404 | wait_event(journal->j_wait_transaction_locked, |
405 | journal->j_barrier_count == 0); | |
406 | goto repeat; | |
407 | } | |
408 | ||
409 | if (!journal->j_running_transaction) { | |
a931da6a TT |
410 | read_unlock(&journal->j_state_lock); |
411 | if (!new_transaction) | |
470decc6 | 412 | goto alloc_transaction; |
a931da6a | 413 | write_lock(&journal->j_state_lock); |
d7961c7f | 414 | if (!journal->j_running_transaction && |
8f7d89f3 | 415 | (handle->h_reserved || !journal->j_barrier_count)) { |
a931da6a TT |
416 | jbd2_get_transaction(journal, new_transaction); |
417 | new_transaction = NULL; | |
470decc6 | 418 | } |
a931da6a TT |
419 | write_unlock(&journal->j_state_lock); |
420 | goto repeat; | |
470decc6 DK |
421 | } |
422 | ||
423 | transaction = journal->j_running_transaction; | |
424 | ||
8f7d89f3 JK |
425 | if (!handle->h_reserved) { |
426 | /* We may have dropped j_state_lock - restart in that case */ | |
b33d9f59 TT |
427 | if (add_transaction_credits(journal, blocks, rsv_blocks)) { |
428 | /* | |
429 | * add_transaction_credits releases | |
430 | * j_state_lock on a non-zero return | |
431 | */ | |
432 | __release(&journal->j_state_lock); | |
8f7d89f3 | 433 | goto repeat; |
b33d9f59 | 434 | } |
8f7d89f3 | 435 | } else { |
470decc6 | 436 | /* |
8f7d89f3 JK |
437 | * We have handle reserved so we are allowed to join T_LOCKED |
438 | * transaction and we don't have to check for transaction size | |
96f1e097 JK |
439 | * and journal space. But we still have to wait while running |
440 | * transaction is being switched to a committing one as it | |
441 | * won't wait for any handles anymore. | |
470decc6 | 442 | */ |
96f1e097 JK |
443 | if (transaction->t_state == T_SWITCH) { |
444 | wait_transaction_switching(journal); | |
445 | goto repeat; | |
446 | } | |
8f7d89f3 JK |
447 | sub_reserved_credits(journal, blocks); |
448 | handle->h_reserved = 0; | |
470decc6 DK |
449 | } |
450 | ||
451 | /* OK, account for the buffers that this operation expects to | |
8dd42046 | 452 | * use and add the handle to the running transaction. |
8dd42046 | 453 | */ |
28e35e42 | 454 | update_t_max_wait(transaction, ts); |
470decc6 | 455 | handle->h_transaction = transaction; |
8f7d89f3 | 456 | handle->h_requested_credits = blocks; |
fdc3ef88 | 457 | handle->h_revoke_credits_requested = handle->h_revoke_credits; |
343d9c28 | 458 | handle->h_start_jiffies = jiffies; |
a51dca9c | 459 | atomic_inc(&transaction->t_updates); |
8dd42046 | 460 | atomic_inc(&transaction->t_handle_count); |
8f7d89f3 JK |
461 | jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n", |
462 | handle, blocks, | |
a51dca9c | 463 | atomic_read(&transaction->t_outstanding_credits), |
76c39904 | 464 | jbd2_log_space_left(journal)); |
a931da6a | 465 | read_unlock(&journal->j_state_lock); |
41a5b913 | 466 | current->journal_info = handle; |
9599b0e5 | 467 | |
ab714aff | 468 | rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_); |
0c2022ec | 469 | jbd2_journal_free_transaction(new_transaction); |
81378da6 MH |
470 | /* |
471 | * Ensure that no allocations done while the transaction is open are | |
472 | * going to recurse back to the fs layer. | |
473 | */ | |
474 | handle->saved_alloc_context = memalloc_nofs_save(); | |
47def826 | 475 | return 0; |
470decc6 DK |
476 | } |
477 | ||
478 | /* Allocate a new handle. This should probably be in a slab... */ | |
479 | static handle_t *new_handle(int nblocks) | |
480 | { | |
af1e76d6 | 481 | handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
470decc6 DK |
482 | if (!handle) |
483 | return NULL; | |
933f1c1e | 484 | handle->h_total_credits = nblocks; |
470decc6 DK |
485 | handle->h_ref = 1; |
486 | ||
487 | return handle; | |
488 | } | |
489 | ||
8f7d89f3 | 490 | handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks, |
fdc3ef88 JK |
491 | int revoke_records, gfp_t gfp_mask, |
492 | unsigned int type, unsigned int line_no) | |
470decc6 DK |
493 | { |
494 | handle_t *handle = journal_current_handle(); | |
495 | int err; | |
496 | ||
497 | if (!journal) | |
498 | return ERR_PTR(-EROFS); | |
499 | ||
500 | if (handle) { | |
501 | J_ASSERT(handle->h_transaction->t_journal == journal); | |
502 | handle->h_ref++; | |
503 | return handle; | |
504 | } | |
505 | ||
fdc3ef88 JK |
506 | nblocks += DIV_ROUND_UP(revoke_records, |
507 | journal->j_revoke_records_per_block); | |
470decc6 DK |
508 | handle = new_handle(nblocks); |
509 | if (!handle) | |
510 | return ERR_PTR(-ENOMEM); | |
8f7d89f3 JK |
511 | if (rsv_blocks) { |
512 | handle_t *rsv_handle; | |
513 | ||
514 | rsv_handle = new_handle(rsv_blocks); | |
515 | if (!rsv_handle) { | |
516 | jbd2_free_handle(handle); | |
517 | return ERR_PTR(-ENOMEM); | |
518 | } | |
519 | rsv_handle->h_reserved = 1; | |
520 | rsv_handle->h_journal = journal; | |
521 | handle->h_rsv_handle = rsv_handle; | |
522 | } | |
fdc3ef88 | 523 | handle->h_revoke_credits = revoke_records; |
470decc6 | 524 | |
47def826 | 525 | err = start_this_handle(journal, handle, gfp_mask); |
470decc6 | 526 | if (err < 0) { |
8f7d89f3 JK |
527 | if (handle->h_rsv_handle) |
528 | jbd2_free_handle(handle->h_rsv_handle); | |
af1e76d6 | 529 | jbd2_free_handle(handle); |
df05c1b8 | 530 | return ERR_PTR(err); |
470decc6 | 531 | } |
343d9c28 TT |
532 | handle->h_type = type; |
533 | handle->h_line_no = line_no; | |
534 | trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, | |
535 | handle->h_transaction->t_tid, type, | |
536 | line_no, nblocks); | |
81378da6 | 537 | |
470decc6 DK |
538 | return handle; |
539 | } | |
47def826 TT |
540 | EXPORT_SYMBOL(jbd2__journal_start); |
541 | ||
542 | ||
91e4775d | 543 | /** |
2bf31d94 | 544 | * jbd2_journal_start() - Obtain a new handle. |
91e4775d MCC |
545 | * @journal: Journal to start transaction on. |
546 | * @nblocks: number of block buffer we might modify | |
547 | * | |
548 | * We make sure that the transaction can guarantee at least nblocks of | |
549 | * modified buffers in the log. We block until the log can guarantee | |
550 | * that much space. Additionally, if rsv_blocks > 0, we also create another | |
551 | * handle with rsv_blocks reserved blocks in the journal. This handle is | |
0c1cba6c | 552 | * stored in h_rsv_handle. It is not attached to any particular transaction |
91e4775d MCC |
553 | * and thus doesn't block transaction commit. If the caller uses this reserved |
554 | * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop() | |
555 | * on the parent handle will dispose the reserved one. Reserved handle has to | |
556 | * be converted to a normal handle using jbd2_journal_start_reserved() before | |
557 | * it can be used. | |
558 | * | |
559 | * Return a pointer to a newly allocated handle, or an ERR_PTR() value | |
560 | * on failure. | |
561 | */ | |
47def826 TT |
562 | handle_t *jbd2_journal_start(journal_t *journal, int nblocks) |
563 | { | |
fdc3ef88 | 564 | return jbd2__journal_start(journal, nblocks, 0, 0, GFP_NOFS, 0, 0); |
47def826 TT |
565 | } |
566 | EXPORT_SYMBOL(jbd2_journal_start); | |
567 | ||
14ff6286 | 568 | static void __jbd2_journal_unreserve_handle(handle_t *handle, transaction_t *t) |
8f7d89f3 JK |
569 | { |
570 | journal_t *journal = handle->h_journal; | |
571 | ||
572 | WARN_ON(!handle->h_reserved); | |
933f1c1e | 573 | sub_reserved_credits(journal, handle->h_total_credits); |
14ff6286 JK |
574 | if (t) |
575 | atomic_sub(handle->h_total_credits, &t->t_outstanding_credits); | |
ec8b6f60 JK |
576 | } |
577 | ||
578 | void jbd2_journal_free_reserved(handle_t *handle) | |
579 | { | |
14ff6286 JK |
580 | journal_t *journal = handle->h_journal; |
581 | ||
582 | /* Get j_state_lock to pin running transaction if it exists */ | |
583 | read_lock(&journal->j_state_lock); | |
584 | __jbd2_journal_unreserve_handle(handle, journal->j_running_transaction); | |
585 | read_unlock(&journal->j_state_lock); | |
8f7d89f3 JK |
586 | jbd2_free_handle(handle); |
587 | } | |
588 | EXPORT_SYMBOL(jbd2_journal_free_reserved); | |
589 | ||
590 | /** | |
2bf31d94 | 591 | * jbd2_journal_start_reserved() - start reserved handle |
8f7d89f3 | 592 | * @handle: handle to start |
f69120ce TH |
593 | * @type: for handle statistics |
594 | * @line_no: for handle statistics | |
8f7d89f3 JK |
595 | * |
596 | * Start handle that has been previously reserved with jbd2_journal_reserve(). | |
597 | * This attaches @handle to the running transaction (or creates one if there's | |
598 | * not transaction running). Unlike jbd2_journal_start() this function cannot | |
599 | * block on journal commit, checkpointing, or similar stuff. It can block on | |
600 | * memory allocation or frozen journal though. | |
601 | * | |
602 | * Return 0 on success, non-zero on error - handle is freed in that case. | |
603 | */ | |
604 | int jbd2_journal_start_reserved(handle_t *handle, unsigned int type, | |
605 | unsigned int line_no) | |
606 | { | |
607 | journal_t *journal = handle->h_journal; | |
608 | int ret = -EIO; | |
609 | ||
610 | if (WARN_ON(!handle->h_reserved)) { | |
611 | /* Someone passed in normal handle? Just stop it. */ | |
612 | jbd2_journal_stop(handle); | |
613 | return ret; | |
614 | } | |
615 | /* | |
616 | * Usefulness of mixing of reserved and unreserved handles is | |
617 | * questionable. So far nobody seems to need it so just error out. | |
618 | */ | |
619 | if (WARN_ON(current->journal_info)) { | |
620 | jbd2_journal_free_reserved(handle); | |
621 | return ret; | |
622 | } | |
623 | ||
624 | handle->h_journal = NULL; | |
8f7d89f3 JK |
625 | /* |
626 | * GFP_NOFS is here because callers are likely from writeback or | |
627 | * similarly constrained call sites | |
628 | */ | |
629 | ret = start_this_handle(journal, handle, GFP_NOFS); | |
92e3b405 | 630 | if (ret < 0) { |
b2569260 | 631 | handle->h_journal = journal; |
8f7d89f3 | 632 | jbd2_journal_free_reserved(handle); |
92e3b405 DC |
633 | return ret; |
634 | } | |
8f7d89f3 JK |
635 | handle->h_type = type; |
636 | handle->h_line_no = line_no; | |
4c273352 XW |
637 | trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, |
638 | handle->h_transaction->t_tid, type, | |
933f1c1e | 639 | line_no, handle->h_total_credits); |
92e3b405 | 640 | return 0; |
8f7d89f3 JK |
641 | } |
642 | EXPORT_SYMBOL(jbd2_journal_start_reserved); | |
470decc6 DK |
643 | |
644 | /** | |
2bf31d94 | 645 | * jbd2_journal_extend() - extend buffer credits. |
470decc6 DK |
646 | * @handle: handle to 'extend' |
647 | * @nblocks: nr blocks to try to extend by. | |
fdc3ef88 | 648 | * @revoke_records: number of revoke records to try to extend by. |
470decc6 DK |
649 | * |
650 | * Some transactions, such as large extends and truncates, can be done | |
651 | * atomically all at once or in several stages. The operation requests | |
bd7ced98 | 652 | * a credit for a number of buffer modifications in advance, but can |
470decc6 DK |
653 | * extend its credit if it needs more. |
654 | * | |
f7f4bccb | 655 | * jbd2_journal_extend tries to give the running handle more buffer credits. |
470decc6 DK |
656 | * It does not guarantee that allocation - this is a best-effort only. |
657 | * The calling process MUST be able to deal cleanly with a failure to | |
658 | * extend here. | |
659 | * | |
660 | * Return 0 on success, non-zero on failure. | |
661 | * | |
662 | * return code < 0 implies an error | |
663 | * return code > 0 implies normal transaction-full status. | |
664 | */ | |
fdc3ef88 | 665 | int jbd2_journal_extend(handle_t *handle, int nblocks, int revoke_records) |
470decc6 DK |
666 | { |
667 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 668 | journal_t *journal; |
470decc6 DK |
669 | int result; |
670 | int wanted; | |
671 | ||
470decc6 | 672 | if (is_handle_aborted(handle)) |
41a5b913 TT |
673 | return -EROFS; |
674 | journal = transaction->t_journal; | |
470decc6 DK |
675 | |
676 | result = 1; | |
677 | ||
a931da6a | 678 | read_lock(&journal->j_state_lock); |
470decc6 DK |
679 | |
680 | /* Don't extend a locked-down transaction! */ | |
41a5b913 | 681 | if (transaction->t_state != T_RUNNING) { |
470decc6 DK |
682 | jbd_debug(3, "denied handle %p %d blocks: " |
683 | "transaction not running\n", handle, nblocks); | |
684 | goto error_out; | |
685 | } | |
686 | ||
fdc3ef88 JK |
687 | nblocks += DIV_ROUND_UP( |
688 | handle->h_revoke_credits_requested + revoke_records, | |
689 | journal->j_revoke_records_per_block) - | |
690 | DIV_ROUND_UP( | |
691 | handle->h_revoke_credits_requested, | |
692 | journal->j_revoke_records_per_block); | |
470decc6 | 693 | spin_lock(&transaction->t_handle_lock); |
fe1e8db5 JK |
694 | wanted = atomic_add_return(nblocks, |
695 | &transaction->t_outstanding_credits); | |
470decc6 DK |
696 | |
697 | if (wanted > journal->j_max_transaction_buffers) { | |
698 | jbd_debug(3, "denied handle %p %d blocks: " | |
699 | "transaction too large\n", handle, nblocks); | |
fe1e8db5 | 700 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
701 | goto unlock; |
702 | } | |
703 | ||
343d9c28 | 704 | trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev, |
41a5b913 | 705 | transaction->t_tid, |
343d9c28 | 706 | handle->h_type, handle->h_line_no, |
933f1c1e | 707 | handle->h_total_credits, |
343d9c28 TT |
708 | nblocks); |
709 | ||
933f1c1e | 710 | handle->h_total_credits += nblocks; |
343d9c28 | 711 | handle->h_requested_credits += nblocks; |
fdc3ef88 JK |
712 | handle->h_revoke_credits += revoke_records; |
713 | handle->h_revoke_credits_requested += revoke_records; | |
470decc6 DK |
714 | result = 0; |
715 | ||
716 | jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); | |
717 | unlock: | |
718 | spin_unlock(&transaction->t_handle_lock); | |
719 | error_out: | |
a931da6a | 720 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
721 | return result; |
722 | } | |
723 | ||
ec8b6f60 JK |
724 | static void stop_this_handle(handle_t *handle) |
725 | { | |
726 | transaction_t *transaction = handle->h_transaction; | |
727 | journal_t *journal = transaction->t_journal; | |
fdc3ef88 | 728 | int revokes; |
ec8b6f60 JK |
729 | |
730 | J_ASSERT(journal_current_handle() == handle); | |
731 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); | |
732 | current->journal_info = NULL; | |
fdc3ef88 JK |
733 | /* |
734 | * Subtract necessary revoke descriptor blocks from handle credits. We | |
735 | * take care to account only for revoke descriptor blocks the | |
736 | * transaction will really need as large sequences of transactions with | |
737 | * small numbers of revokes are relatively common. | |
738 | */ | |
739 | revokes = handle->h_revoke_credits_requested - handle->h_revoke_credits; | |
740 | if (revokes) { | |
741 | int t_revokes, revoke_descriptors; | |
742 | int rr_per_blk = journal->j_revoke_records_per_block; | |
743 | ||
744 | WARN_ON_ONCE(DIV_ROUND_UP(revokes, rr_per_blk) | |
933f1c1e | 745 | > handle->h_total_credits); |
fdc3ef88 JK |
746 | t_revokes = atomic_add_return(revokes, |
747 | &transaction->t_outstanding_revokes); | |
748 | revoke_descriptors = | |
749 | DIV_ROUND_UP(t_revokes, rr_per_blk) - | |
750 | DIV_ROUND_UP(t_revokes - revokes, rr_per_blk); | |
933f1c1e | 751 | handle->h_total_credits -= revoke_descriptors; |
fdc3ef88 | 752 | } |
933f1c1e | 753 | atomic_sub(handle->h_total_credits, |
ec8b6f60 JK |
754 | &transaction->t_outstanding_credits); |
755 | if (handle->h_rsv_handle) | |
14ff6286 JK |
756 | __jbd2_journal_unreserve_handle(handle->h_rsv_handle, |
757 | transaction); | |
ec8b6f60 JK |
758 | if (atomic_dec_and_test(&transaction->t_updates)) |
759 | wake_up(&journal->j_wait_updates); | |
760 | ||
50b8b3f8 | 761 | rwsem_release(&journal->j_trans_commit_map, _THIS_IP_); |
ec8b6f60 JK |
762 | /* |
763 | * Scope of the GFP_NOFS context is over here and so we can restore the | |
764 | * original alloc context. | |
765 | */ | |
766 | memalloc_nofs_restore(handle->saved_alloc_context); | |
767 | } | |
470decc6 DK |
768 | |
769 | /** | |
2bf31d94 | 770 | * jbd2__journal_restart() - restart a handle . |
470decc6 DK |
771 | * @handle: handle to restart |
772 | * @nblocks: nr credits requested | |
fdc3ef88 | 773 | * @revoke_records: number of revoke record credits requested |
f69120ce | 774 | * @gfp_mask: memory allocation flags (for start_this_handle) |
470decc6 DK |
775 | * |
776 | * Restart a handle for a multi-transaction filesystem | |
777 | * operation. | |
778 | * | |
f7f4bccb MC |
779 | * If the jbd2_journal_extend() call above fails to grant new buffer credits |
780 | * to a running handle, a call to jbd2_journal_restart will commit the | |
470decc6 | 781 | * handle's transaction so far and reattach the handle to a new |
bd7ced98 | 782 | * transaction capable of guaranteeing the requested number of |
8f7d89f3 JK |
783 | * credits. We preserve reserved handle if there's any attached to the |
784 | * passed in handle. | |
470decc6 | 785 | */ |
fdc3ef88 JK |
786 | int jbd2__journal_restart(handle_t *handle, int nblocks, int revoke_records, |
787 | gfp_t gfp_mask) | |
470decc6 DK |
788 | { |
789 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 790 | journal_t *journal; |
e4471831 | 791 | tid_t tid; |
ec8b6f60 | 792 | int need_to_start; |
0094f981 | 793 | int ret; |
470decc6 DK |
794 | |
795 | /* If we've had an abort of any type, don't even think about | |
796 | * actually doing the restart! */ | |
797 | if (is_handle_aborted(handle)) | |
798 | return 0; | |
41a5b913 | 799 | journal = transaction->t_journal; |
ec8b6f60 | 800 | tid = transaction->t_tid; |
470decc6 DK |
801 | |
802 | /* | |
803 | * First unlink the handle from its current transaction, and start the | |
804 | * commit on that. | |
805 | */ | |
ec8b6f60 JK |
806 | jbd_debug(2, "restarting handle %p\n", handle); |
807 | stop_this_handle(handle); | |
41a5b913 | 808 | handle->h_transaction = NULL; |
470decc6 | 809 | |
ec8b6f60 JK |
810 | /* |
811 | * TODO: If we use READ_ONCE / WRITE_ONCE for j_commit_request we can | |
812 | * get rid of pointless j_state_lock traffic like this. | |
813 | */ | |
814 | read_lock(&journal->j_state_lock); | |
e4471831 | 815 | need_to_start = !tid_geq(journal->j_commit_request, tid); |
a931da6a | 816 | read_unlock(&journal->j_state_lock); |
e4471831 TT |
817 | if (need_to_start) |
818 | jbd2_log_start_commit(journal, tid); | |
933f1c1e | 819 | handle->h_total_credits = nblocks + |
fdc3ef88 JK |
820 | DIV_ROUND_UP(revoke_records, |
821 | journal->j_revoke_records_per_block); | |
822 | handle->h_revoke_credits = revoke_records; | |
47def826 | 823 | ret = start_this_handle(journal, handle, gfp_mask); |
0094f981 JK |
824 | trace_jbd2_handle_restart(journal->j_fs_dev->bd_dev, |
825 | ret ? 0 : handle->h_transaction->t_tid, | |
826 | handle->h_type, handle->h_line_no, | |
827 | handle->h_total_credits); | |
470decc6 DK |
828 | return ret; |
829 | } | |
47def826 | 830 | EXPORT_SYMBOL(jbd2__journal_restart); |
470decc6 DK |
831 | |
832 | ||
47def826 TT |
833 | int jbd2_journal_restart(handle_t *handle, int nblocks) |
834 | { | |
fdc3ef88 | 835 | return jbd2__journal_restart(handle, nblocks, 0, GFP_NOFS); |
47def826 TT |
836 | } |
837 | EXPORT_SYMBOL(jbd2_journal_restart); | |
838 | ||
470decc6 | 839 | /** |
2bf31d94 | 840 | * jbd2_journal_lock_updates () - establish a transaction barrier. |
470decc6 DK |
841 | * @journal: Journal to establish a barrier on. |
842 | * | |
843 | * This locks out any further updates from being started, and blocks | |
844 | * until all existing updates have completed, returning only once the | |
845 | * journal is in a quiescent state with no updates running. | |
846 | * | |
847 | * The journal lock should not be held on entry. | |
848 | */ | |
f7f4bccb | 849 | void jbd2_journal_lock_updates(journal_t *journal) |
470decc6 DK |
850 | { |
851 | DEFINE_WAIT(wait); | |
852 | ||
1eaa566d JK |
853 | jbd2_might_wait_for_commit(journal); |
854 | ||
a931da6a | 855 | write_lock(&journal->j_state_lock); |
470decc6 DK |
856 | ++journal->j_barrier_count; |
857 | ||
8f7d89f3 JK |
858 | /* Wait until there are no reserved handles */ |
859 | if (atomic_read(&journal->j_reserved_credits)) { | |
860 | write_unlock(&journal->j_state_lock); | |
861 | wait_event(journal->j_wait_reserved, | |
862 | atomic_read(&journal->j_reserved_credits) == 0); | |
863 | write_lock(&journal->j_state_lock); | |
864 | } | |
865 | ||
470decc6 DK |
866 | /* Wait until there are no running updates */ |
867 | while (1) { | |
868 | transaction_t *transaction = journal->j_running_transaction; | |
869 | ||
870 | if (!transaction) | |
871 | break; | |
872 | ||
873 | spin_lock(&transaction->t_handle_lock); | |
9837d8e9 JK |
874 | prepare_to_wait(&journal->j_wait_updates, &wait, |
875 | TASK_UNINTERRUPTIBLE); | |
a51dca9c | 876 | if (!atomic_read(&transaction->t_updates)) { |
470decc6 | 877 | spin_unlock(&transaction->t_handle_lock); |
9837d8e9 | 878 | finish_wait(&journal->j_wait_updates, &wait); |
470decc6 DK |
879 | break; |
880 | } | |
470decc6 | 881 | spin_unlock(&transaction->t_handle_lock); |
a931da6a | 882 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
883 | schedule(); |
884 | finish_wait(&journal->j_wait_updates, &wait); | |
a931da6a | 885 | write_lock(&journal->j_state_lock); |
470decc6 | 886 | } |
a931da6a | 887 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
888 | |
889 | /* | |
890 | * We have now established a barrier against other normal updates, but | |
f7f4bccb | 891 | * we also need to barrier against other jbd2_journal_lock_updates() calls |
470decc6 DK |
892 | * to make sure that we serialise special journal-locked operations |
893 | * too. | |
894 | */ | |
895 | mutex_lock(&journal->j_barrier); | |
896 | } | |
897 | ||
898 | /** | |
2bf31d94 | 899 | * jbd2_journal_unlock_updates () - release barrier |
470decc6 DK |
900 | * @journal: Journal to release the barrier on. |
901 | * | |
f7f4bccb | 902 | * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
470decc6 DK |
903 | * |
904 | * Should be called without the journal lock held. | |
905 | */ | |
f7f4bccb | 906 | void jbd2_journal_unlock_updates (journal_t *journal) |
470decc6 DK |
907 | { |
908 | J_ASSERT(journal->j_barrier_count != 0); | |
909 | ||
910 | mutex_unlock(&journal->j_barrier); | |
a931da6a | 911 | write_lock(&journal->j_state_lock); |
470decc6 | 912 | --journal->j_barrier_count; |
a931da6a | 913 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
914 | wake_up(&journal->j_wait_transaction_locked); |
915 | } | |
916 | ||
f91d1d04 | 917 | static void warn_dirty_buffer(struct buffer_head *bh) |
470decc6 | 918 | { |
f91d1d04 | 919 | printk(KERN_WARNING |
a1c6f057 | 920 | "JBD2: Spotted dirty metadata buffer (dev = %pg, blocknr = %llu). " |
f91d1d04 JK |
921 | "There's a risk of filesystem corruption in case of system " |
922 | "crash.\n", | |
a1c6f057 | 923 | bh->b_bdev, (unsigned long long)bh->b_blocknr); |
470decc6 DK |
924 | } |
925 | ||
ee57aba1 JK |
926 | /* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */ |
927 | static void jbd2_freeze_jh_data(struct journal_head *jh) | |
928 | { | |
929 | struct page *page; | |
930 | int offset; | |
931 | char *source; | |
932 | struct buffer_head *bh = jh2bh(jh); | |
933 | ||
934 | J_EXPECT_JH(jh, buffer_uptodate(bh), "Possible IO failure.\n"); | |
935 | page = bh->b_page; | |
936 | offset = offset_in_page(bh->b_data); | |
937 | source = kmap_atomic(page); | |
938 | /* Fire data frozen trigger just before we copy the data */ | |
939 | jbd2_buffer_frozen_trigger(jh, source + offset, jh->b_triggers); | |
940 | memcpy(jh->b_frozen_data, source + offset, bh->b_size); | |
941 | kunmap_atomic(source); | |
942 | ||
943 | /* | |
944 | * Now that the frozen data is saved off, we need to store any matching | |
945 | * triggers. | |
946 | */ | |
947 | jh->b_frozen_triggers = jh->b_triggers; | |
948 | } | |
949 | ||
470decc6 DK |
950 | /* |
951 | * If the buffer is already part of the current transaction, then there | |
952 | * is nothing we need to do. If it is already part of a prior | |
953 | * transaction which we are still committing to disk, then we need to | |
954 | * make sure that we do not overwrite the old copy: we do copy-out to | |
955 | * preserve the copy going to disk. We also account the buffer against | |
956 | * the handle's metadata buffer credits (unless the buffer is already | |
957 | * part of the transaction, that is). | |
958 | * | |
959 | */ | |
960 | static int | |
961 | do_get_write_access(handle_t *handle, struct journal_head *jh, | |
962 | int force_copy) | |
963 | { | |
964 | struct buffer_head *bh; | |
41a5b913 | 965 | transaction_t *transaction = handle->h_transaction; |
470decc6 DK |
966 | journal_t *journal; |
967 | int error; | |
968 | char *frozen_buffer = NULL; | |
f783f091 | 969 | unsigned long start_lock, time_lock; |
470decc6 | 970 | |
470decc6 DK |
971 | journal = transaction->t_journal; |
972 | ||
cfef2c6a | 973 | jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy); |
470decc6 DK |
974 | |
975 | JBUFFER_TRACE(jh, "entry"); | |
976 | repeat: | |
977 | bh = jh2bh(jh); | |
978 | ||
979 | /* @@@ Need to check for errors here at some point. */ | |
980 | ||
f783f091 | 981 | start_lock = jiffies; |
470decc6 | 982 | lock_buffer(bh); |
46417064 | 983 | spin_lock(&jh->b_state_lock); |
470decc6 | 984 | |
f783f091 TT |
985 | /* If it takes too long to lock the buffer, trace it */ |
986 | time_lock = jbd2_time_diff(start_lock, jiffies); | |
987 | if (time_lock > HZ/10) | |
988 | trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev, | |
989 | jiffies_to_msecs(time_lock)); | |
990 | ||
470decc6 DK |
991 | /* We now hold the buffer lock so it is safe to query the buffer |
992 | * state. Is the buffer dirty? | |
993 | * | |
994 | * If so, there are two possibilities. The buffer may be | |
995 | * non-journaled, and undergoing a quite legitimate writeback. | |
996 | * Otherwise, it is journaled, and we don't expect dirty buffers | |
997 | * in that state (the buffers should be marked JBD_Dirty | |
998 | * instead.) So either the IO is being done under our own | |
999 | * control and this is a bug, or it's a third party IO such as | |
1000 | * dump(8) (which may leave the buffer scheduled for read --- | |
1001 | * ie. locked but not dirty) or tune2fs (which may actually have | |
1002 | * the buffer dirtied, ugh.) */ | |
1003 | ||
1004 | if (buffer_dirty(bh)) { | |
1005 | /* | |
1006 | * First question: is this buffer already part of the current | |
1007 | * transaction or the existing committing transaction? | |
1008 | */ | |
1009 | if (jh->b_transaction) { | |
1010 | J_ASSERT_JH(jh, | |
1011 | jh->b_transaction == transaction || | |
1012 | jh->b_transaction == | |
1013 | journal->j_committing_transaction); | |
1014 | if (jh->b_next_transaction) | |
1015 | J_ASSERT_JH(jh, jh->b_next_transaction == | |
1016 | transaction); | |
f91d1d04 | 1017 | warn_dirty_buffer(bh); |
470decc6 DK |
1018 | } |
1019 | /* | |
1020 | * In any case we need to clean the dirty flag and we must | |
1021 | * do it under the buffer lock to be sure we don't race | |
1022 | * with running write-out. | |
1023 | */ | |
f91d1d04 JK |
1024 | JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
1025 | clear_buffer_dirty(bh); | |
1026 | set_buffer_jbddirty(bh); | |
470decc6 DK |
1027 | } |
1028 | ||
1029 | unlock_buffer(bh); | |
1030 | ||
1031 | error = -EROFS; | |
1032 | if (is_handle_aborted(handle)) { | |
46417064 | 1033 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
1034 | goto out; |
1035 | } | |
1036 | error = 0; | |
1037 | ||
1038 | /* | |
1039 | * The buffer is already part of this transaction if b_transaction or | |
1040 | * b_next_transaction points to it | |
1041 | */ | |
1042 | if (jh->b_transaction == transaction || | |
1043 | jh->b_next_transaction == transaction) | |
1044 | goto done; | |
1045 | ||
9fc7c63a JB |
1046 | /* |
1047 | * this is the first time this transaction is touching this buffer, | |
1048 | * reset the modified flag | |
1049 | */ | |
561405f0 | 1050 | jh->b_modified = 0; |
9fc7c63a | 1051 | |
8b00f400 JK |
1052 | /* |
1053 | * If the buffer is not journaled right now, we need to make sure it | |
1054 | * doesn't get written to disk before the caller actually commits the | |
1055 | * new data | |
1056 | */ | |
1057 | if (!jh->b_transaction) { | |
1058 | JBUFFER_TRACE(jh, "no transaction"); | |
1059 | J_ASSERT_JH(jh, !jh->b_next_transaction); | |
1060 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); | |
de92c8ca JK |
1061 | /* |
1062 | * Make sure all stores to jh (b_modified, b_frozen_data) are | |
1063 | * visible before attaching it to the running transaction. | |
1064 | * Paired with barrier in jbd2_write_access_granted() | |
1065 | */ | |
1066 | smp_wmb(); | |
8b00f400 JK |
1067 | spin_lock(&journal->j_list_lock); |
1068 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); | |
1069 | spin_unlock(&journal->j_list_lock); | |
1070 | goto done; | |
1071 | } | |
470decc6 DK |
1072 | /* |
1073 | * If there is already a copy-out version of this buffer, then we don't | |
1074 | * need to make another one | |
1075 | */ | |
1076 | if (jh->b_frozen_data) { | |
1077 | JBUFFER_TRACE(jh, "has frozen data"); | |
1078 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
de92c8ca | 1079 | goto attach_next; |
470decc6 DK |
1080 | } |
1081 | ||
8b00f400 JK |
1082 | JBUFFER_TRACE(jh, "owned by older transaction"); |
1083 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
1084 | J_ASSERT_JH(jh, jh->b_transaction == journal->j_committing_transaction); | |
470decc6 | 1085 | |
8b00f400 JK |
1086 | /* |
1087 | * There is one case we have to be very careful about. If the | |
1088 | * committing transaction is currently writing this buffer out to disk | |
1089 | * and has NOT made a copy-out, then we cannot modify the buffer | |
1090 | * contents at all right now. The essence of copy-out is that it is | |
1091 | * the extra copy, not the primary copy, which gets journaled. If the | |
1092 | * primary copy is already going to disk then we cannot do copy-out | |
1093 | * here. | |
1094 | */ | |
1095 | if (buffer_shadow(bh)) { | |
1096 | JBUFFER_TRACE(jh, "on shadow: sleep"); | |
46417064 | 1097 | spin_unlock(&jh->b_state_lock); |
8b00f400 JK |
1098 | wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE); |
1099 | goto repeat; | |
1100 | } | |
470decc6 | 1101 | |
8b00f400 JK |
1102 | /* |
1103 | * Only do the copy if the currently-owning transaction still needs it. | |
1104 | * If buffer isn't on BJ_Metadata list, the committing transaction is | |
1105 | * past that stage (here we use the fact that BH_Shadow is set under | |
1106 | * bh_state lock together with refiling to BJ_Shadow list and at this | |
1107 | * point we know the buffer doesn't have BH_Shadow set). | |
1108 | * | |
1109 | * Subtle point, though: if this is a get_undo_access, then we will be | |
1110 | * relying on the frozen_data to contain the new value of the | |
1111 | * committed_data record after the transaction, so we HAVE to force the | |
1112 | * frozen_data copy in that case. | |
1113 | */ | |
1114 | if (jh->b_jlist == BJ_Metadata || force_copy) { | |
1115 | JBUFFER_TRACE(jh, "generate frozen data"); | |
1116 | if (!frozen_buffer) { | |
1117 | JBUFFER_TRACE(jh, "allocate memory for buffer"); | |
46417064 | 1118 | spin_unlock(&jh->b_state_lock); |
490c1b44 MH |
1119 | frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size, |
1120 | GFP_NOFS | __GFP_NOFAIL); | |
8b00f400 | 1121 | goto repeat; |
470decc6 | 1122 | } |
8b00f400 JK |
1123 | jh->b_frozen_data = frozen_buffer; |
1124 | frozen_buffer = NULL; | |
1125 | jbd2_freeze_jh_data(jh); | |
470decc6 | 1126 | } |
de92c8ca JK |
1127 | attach_next: |
1128 | /* | |
1129 | * Make sure all stores to jh (b_modified, b_frozen_data) are visible | |
1130 | * before attaching it to the running transaction. Paired with barrier | |
1131 | * in jbd2_write_access_granted() | |
1132 | */ | |
1133 | smp_wmb(); | |
8b00f400 | 1134 | jh->b_next_transaction = transaction; |
470decc6 DK |
1135 | |
1136 | done: | |
46417064 | 1137 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
1138 | |
1139 | /* | |
1140 | * If we are about to journal a buffer, then any revoke pending on it is | |
1141 | * no longer valid | |
1142 | */ | |
f7f4bccb | 1143 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 DK |
1144 | |
1145 | out: | |
1146 | if (unlikely(frozen_buffer)) /* It's usually NULL */ | |
af1e76d6 | 1147 | jbd2_free(frozen_buffer, bh->b_size); |
470decc6 DK |
1148 | |
1149 | JBUFFER_TRACE(jh, "exit"); | |
1150 | return error; | |
1151 | } | |
1152 | ||
de92c8ca | 1153 | /* Fast check whether buffer is already attached to the required transaction */ |
087ffd4e JB |
1154 | static bool jbd2_write_access_granted(handle_t *handle, struct buffer_head *bh, |
1155 | bool undo) | |
de92c8ca JK |
1156 | { |
1157 | struct journal_head *jh; | |
1158 | bool ret = false; | |
1159 | ||
1160 | /* Dirty buffers require special handling... */ | |
1161 | if (buffer_dirty(bh)) | |
1162 | return false; | |
1163 | ||
1164 | /* | |
1165 | * RCU protects us from dereferencing freed pages. So the checks we do | |
1166 | * are guaranteed not to oops. However the jh slab object can get freed | |
1167 | * & reallocated while we work with it. So we have to be careful. When | |
1168 | * we see jh attached to the running transaction, we know it must stay | |
1169 | * so until the transaction is committed. Thus jh won't be freed and | |
1170 | * will be attached to the same bh while we run. However it can | |
1171 | * happen jh gets freed, reallocated, and attached to the transaction | |
1172 | * just after we get pointer to it from bh. So we have to be careful | |
1173 | * and recheck jh still belongs to our bh before we return success. | |
1174 | */ | |
1175 | rcu_read_lock(); | |
1176 | if (!buffer_jbd(bh)) | |
1177 | goto out; | |
1178 | /* This should be bh2jh() but that doesn't work with inline functions */ | |
1179 | jh = READ_ONCE(bh->b_private); | |
1180 | if (!jh) | |
1181 | goto out; | |
087ffd4e JB |
1182 | /* For undo access buffer must have data copied */ |
1183 | if (undo && !jh->b_committed_data) | |
1184 | goto out; | |
6c5d9112 QC |
1185 | if (READ_ONCE(jh->b_transaction) != handle->h_transaction && |
1186 | READ_ONCE(jh->b_next_transaction) != handle->h_transaction) | |
de92c8ca JK |
1187 | goto out; |
1188 | /* | |
1189 | * There are two reasons for the barrier here: | |
1190 | * 1) Make sure to fetch b_bh after we did previous checks so that we | |
1191 | * detect when jh went through free, realloc, attach to transaction | |
1192 | * while we were checking. Paired with implicit barrier in that path. | |
1193 | * 2) So that access to bh done after jbd2_write_access_granted() | |
1194 | * doesn't get reordered and see inconsistent state of concurrent | |
1195 | * do_get_write_access(). | |
1196 | */ | |
1197 | smp_mb(); | |
1198 | if (unlikely(jh->b_bh != bh)) | |
1199 | goto out; | |
1200 | ret = true; | |
1201 | out: | |
1202 | rcu_read_unlock(); | |
1203 | return ret; | |
1204 | } | |
1205 | ||
470decc6 | 1206 | /** |
2bf31d94 MCC |
1207 | * jbd2_journal_get_write_access() - notify intent to modify a buffer |
1208 | * for metadata (not data) update. | |
470decc6 DK |
1209 | * @handle: transaction to add buffer modifications to |
1210 | * @bh: bh to be used for metadata writes | |
470decc6 | 1211 | * |
df1b560a | 1212 | * Returns: error code or 0 on success. |
470decc6 DK |
1213 | * |
1214 | * In full data journalling mode the buffer may be of type BJ_AsyncData, | |
df1b560a | 1215 | * because we're ``write()ing`` a buffer which is also part of a shared mapping. |
470decc6 DK |
1216 | */ |
1217 | ||
f7f4bccb | 1218 | int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
470decc6 | 1219 | { |
de92c8ca | 1220 | struct journal_head *jh; |
470decc6 DK |
1221 | int rc; |
1222 | ||
8eedabfd | 1223 | if (is_handle_aborted(handle)) |
1224 | return -EROFS; | |
1225 | ||
087ffd4e | 1226 | if (jbd2_write_access_granted(handle, bh, false)) |
de92c8ca JK |
1227 | return 0; |
1228 | ||
1229 | jh = jbd2_journal_add_journal_head(bh); | |
470decc6 DK |
1230 | /* We do not want to get caught playing with fields which the |
1231 | * log thread also manipulates. Make sure that the buffer | |
1232 | * completes any outstanding IO before proceeding. */ | |
1233 | rc = do_get_write_access(handle, jh, 0); | |
f7f4bccb | 1234 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1235 | return rc; |
1236 | } | |
1237 | ||
1238 | ||
1239 | /* | |
1240 | * When the user wants to journal a newly created buffer_head | |
1241 | * (ie. getblk() returned a new buffer and we are going to populate it | |
1242 | * manually rather than reading off disk), then we need to keep the | |
1243 | * buffer_head locked until it has been completely filled with new | |
1244 | * data. In this case, we should be able to make the assertion that | |
1245 | * the bh is not already part of an existing transaction. | |
1246 | * | |
1247 | * The buffer should already be locked by the caller by this point. | |
1248 | * There is no lock ranking violation: it was a newly created, | |
1249 | * unlocked buffer beforehand. */ | |
1250 | ||
1251 | /** | |
2bf31d94 | 1252 | * jbd2_journal_get_create_access () - notify intent to use newly created bh |
470decc6 DK |
1253 | * @handle: transaction to new buffer to |
1254 | * @bh: new buffer. | |
1255 | * | |
1256 | * Call this if you create a new bh. | |
1257 | */ | |
f7f4bccb | 1258 | int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1259 | { |
1260 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1261 | journal_t *journal; |
f7f4bccb | 1262 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
1263 | int err; |
1264 | ||
1265 | jbd_debug(5, "journal_head %p\n", jh); | |
1266 | err = -EROFS; | |
1267 | if (is_handle_aborted(handle)) | |
1268 | goto out; | |
41a5b913 | 1269 | journal = transaction->t_journal; |
470decc6 DK |
1270 | err = 0; |
1271 | ||
1272 | JBUFFER_TRACE(jh, "entry"); | |
1273 | /* | |
1274 | * The buffer may already belong to this transaction due to pre-zeroing | |
1275 | * in the filesystem's new_block code. It may also be on the previous, | |
1276 | * committing transaction's lists, but it HAS to be in Forget state in | |
1277 | * that case: the transaction must have deleted the buffer for it to be | |
1278 | * reused here. | |
1279 | */ | |
46417064 | 1280 | spin_lock(&jh->b_state_lock); |
470decc6 DK |
1281 | J_ASSERT_JH(jh, (jh->b_transaction == transaction || |
1282 | jh->b_transaction == NULL || | |
1283 | (jh->b_transaction == journal->j_committing_transaction && | |
1284 | jh->b_jlist == BJ_Forget))); | |
1285 | ||
1286 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
1287 | J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); | |
1288 | ||
1289 | if (jh->b_transaction == NULL) { | |
f91d1d04 JK |
1290 | /* |
1291 | * Previous jbd2_journal_forget() could have left the buffer | |
1292 | * with jbddirty bit set because it was being committed. When | |
1293 | * the commit finished, we've filed the buffer for | |
1294 | * checkpointing and marked it dirty. Now we are reallocating | |
1295 | * the buffer so the transaction freeing it must have | |
1296 | * committed and so it's safe to clear the dirty bit. | |
1297 | */ | |
1298 | clear_buffer_dirty(jh2bh(jh)); | |
9fc7c63a JB |
1299 | /* first access by this transaction */ |
1300 | jh->b_modified = 0; | |
1301 | ||
470decc6 | 1302 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
6e4862a5 | 1303 | spin_lock(&journal->j_list_lock); |
f7f4bccb | 1304 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
559cce69 | 1305 | spin_unlock(&journal->j_list_lock); |
470decc6 | 1306 | } else if (jh->b_transaction == journal->j_committing_transaction) { |
9fc7c63a JB |
1307 | /* first access by this transaction */ |
1308 | jh->b_modified = 0; | |
1309 | ||
470decc6 | 1310 | JBUFFER_TRACE(jh, "set next transaction"); |
6e4862a5 | 1311 | spin_lock(&journal->j_list_lock); |
470decc6 | 1312 | jh->b_next_transaction = transaction; |
559cce69 | 1313 | spin_unlock(&journal->j_list_lock); |
470decc6 | 1314 | } |
46417064 | 1315 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
1316 | |
1317 | /* | |
1318 | * akpm: I added this. ext3_alloc_branch can pick up new indirect | |
1319 | * blocks which contain freed but then revoked metadata. We need | |
1320 | * to cancel the revoke in case we end up freeing it yet again | |
1321 | * and the reallocating as data - this would cause a second revoke, | |
1322 | * which hits an assertion error. | |
1323 | */ | |
1324 | JBUFFER_TRACE(jh, "cancelling revoke"); | |
f7f4bccb | 1325 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 | 1326 | out: |
3991b400 | 1327 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1328 | return err; |
1329 | } | |
1330 | ||
1331 | /** | |
2bf31d94 | 1332 | * jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
470decc6 DK |
1333 | * non-rewindable consequences |
1334 | * @handle: transaction | |
1335 | * @bh: buffer to undo | |
470decc6 DK |
1336 | * |
1337 | * Sometimes there is a need to distinguish between metadata which has | |
1338 | * been committed to disk and that which has not. The ext3fs code uses | |
1339 | * this for freeing and allocating space, we have to make sure that we | |
1340 | * do not reuse freed space until the deallocation has been committed, | |
1341 | * since if we overwrote that space we would make the delete | |
1342 | * un-rewindable in case of a crash. | |
1343 | * | |
f7f4bccb | 1344 | * To deal with that, jbd2_journal_get_undo_access requests write access to a |
470decc6 DK |
1345 | * buffer for parts of non-rewindable operations such as delete |
1346 | * operations on the bitmaps. The journaling code must keep a copy of | |
1347 | * the buffer's contents prior to the undo_access call until such time | |
1348 | * as we know that the buffer has definitely been committed to disk. | |
1349 | * | |
1350 | * We never need to know which transaction the committed data is part | |
1351 | * of, buffers touched here are guaranteed to be dirtied later and so | |
1352 | * will be committed to a new transaction in due course, at which point | |
1353 | * we can discard the old committed data pointer. | |
1354 | * | |
1355 | * Returns error number or 0 on success. | |
1356 | */ | |
f7f4bccb | 1357 | int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1358 | { |
1359 | int err; | |
de92c8ca | 1360 | struct journal_head *jh; |
470decc6 DK |
1361 | char *committed_data = NULL; |
1362 | ||
8eedabfd | 1363 | if (is_handle_aborted(handle)) |
1364 | return -EROFS; | |
1365 | ||
087ffd4e | 1366 | if (jbd2_write_access_granted(handle, bh, true)) |
de92c8ca | 1367 | return 0; |
470decc6 | 1368 | |
de92c8ca | 1369 | jh = jbd2_journal_add_journal_head(bh); |
01215d3e | 1370 | JBUFFER_TRACE(jh, "entry"); |
1371 | ||
470decc6 DK |
1372 | /* |
1373 | * Do this first --- it can drop the journal lock, so we want to | |
1374 | * make sure that obtaining the committed_data is done | |
1375 | * atomically wrt. completion of any outstanding commits. | |
1376 | */ | |
1377 | err = do_get_write_access(handle, jh, 1); | |
1378 | if (err) | |
1379 | goto out; | |
1380 | ||
1381 | repeat: | |
490c1b44 MH |
1382 | if (!jh->b_committed_data) |
1383 | committed_data = jbd2_alloc(jh2bh(jh)->b_size, | |
1384 | GFP_NOFS|__GFP_NOFAIL); | |
470decc6 | 1385 | |
46417064 | 1386 | spin_lock(&jh->b_state_lock); |
470decc6 DK |
1387 | if (!jh->b_committed_data) { |
1388 | /* Copy out the current buffer contents into the | |
1389 | * preserved, committed copy. */ | |
1390 | JBUFFER_TRACE(jh, "generate b_committed data"); | |
1391 | if (!committed_data) { | |
46417064 | 1392 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
1393 | goto repeat; |
1394 | } | |
1395 | ||
1396 | jh->b_committed_data = committed_data; | |
1397 | committed_data = NULL; | |
1398 | memcpy(jh->b_committed_data, bh->b_data, bh->b_size); | |
1399 | } | |
46417064 | 1400 | spin_unlock(&jh->b_state_lock); |
470decc6 | 1401 | out: |
f7f4bccb | 1402 | jbd2_journal_put_journal_head(jh); |
470decc6 | 1403 | if (unlikely(committed_data)) |
af1e76d6 | 1404 | jbd2_free(committed_data, bh->b_size); |
470decc6 DK |
1405 | return err; |
1406 | } | |
1407 | ||
e06c8227 | 1408 | /** |
2bf31d94 | 1409 | * jbd2_journal_set_triggers() - Add triggers for commit writeout |
e06c8227 JB |
1410 | * @bh: buffer to trigger on |
1411 | * @type: struct jbd2_buffer_trigger_type containing the trigger(s). | |
1412 | * | |
1413 | * Set any triggers on this journal_head. This is always safe, because | |
1414 | * triggers for a committing buffer will be saved off, and triggers for | |
1415 | * a running transaction will match the buffer in that transaction. | |
1416 | * | |
1417 | * Call with NULL to clear the triggers. | |
1418 | */ | |
1419 | void jbd2_journal_set_triggers(struct buffer_head *bh, | |
1420 | struct jbd2_buffer_trigger_type *type) | |
1421 | { | |
ad56edad | 1422 | struct journal_head *jh = jbd2_journal_grab_journal_head(bh); |
e06c8227 | 1423 | |
188c299e | 1424 | if (WARN_ON_ONCE(!jh)) |
ad56edad | 1425 | return; |
e06c8227 | 1426 | jh->b_triggers = type; |
ad56edad | 1427 | jbd2_journal_put_journal_head(jh); |
e06c8227 JB |
1428 | } |
1429 | ||
13ceef09 | 1430 | void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data, |
e06c8227 JB |
1431 | struct jbd2_buffer_trigger_type *triggers) |
1432 | { | |
1433 | struct buffer_head *bh = jh2bh(jh); | |
1434 | ||
13ceef09 | 1435 | if (!triggers || !triggers->t_frozen) |
e06c8227 JB |
1436 | return; |
1437 | ||
13ceef09 | 1438 | triggers->t_frozen(triggers, bh, mapped_data, bh->b_size); |
e06c8227 JB |
1439 | } |
1440 | ||
1441 | void jbd2_buffer_abort_trigger(struct journal_head *jh, | |
1442 | struct jbd2_buffer_trigger_type *triggers) | |
1443 | { | |
1444 | if (!triggers || !triggers->t_abort) | |
1445 | return; | |
1446 | ||
1447 | triggers->t_abort(triggers, jh2bh(jh)); | |
1448 | } | |
1449 | ||
470decc6 | 1450 | /** |
2bf31d94 | 1451 | * jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
470decc6 DK |
1452 | * @handle: transaction to add buffer to. |
1453 | * @bh: buffer to mark | |
1454 | * | |
1455 | * mark dirty metadata which needs to be journaled as part of the current | |
1456 | * transaction. | |
1457 | * | |
9ea7a0df TT |
1458 | * The buffer must have previously had jbd2_journal_get_write_access() |
1459 | * called so that it has a valid journal_head attached to the buffer | |
1460 | * head. | |
1461 | * | |
470decc6 DK |
1462 | * The buffer is placed on the transaction's metadata list and is marked |
1463 | * as belonging to the transaction. | |
1464 | * | |
1465 | * Returns error number or 0 on success. | |
1466 | * | |
1467 | * Special care needs to be taken if the buffer already belongs to the | |
1468 | * current committing transaction (in which case we should have frozen | |
1469 | * data present for that commit). In that case, we don't relink the | |
1470 | * buffer: that only gets done when the old transaction finally | |
1471 | * completes its commit. | |
1472 | */ | |
f7f4bccb | 1473 | int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1474 | { |
1475 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1476 | journal_t *journal; |
ad56edad | 1477 | struct journal_head *jh; |
9ea7a0df | 1478 | int ret = 0; |
470decc6 | 1479 | |
470decc6 | 1480 | if (is_handle_aborted(handle)) |
41a5b913 | 1481 | return -EROFS; |
01215d3e | 1482 | if (!buffer_jbd(bh)) |
1483 | return -EUCLEAN; | |
1484 | ||
6e06ae88 JK |
1485 | /* |
1486 | * We don't grab jh reference here since the buffer must be part | |
1487 | * of the running transaction. | |
1488 | */ | |
1489 | jh = bh2jh(bh); | |
01215d3e | 1490 | jbd_debug(5, "journal_head %p\n", jh); |
1491 | JBUFFER_TRACE(jh, "entry"); | |
1492 | ||
6e06ae88 JK |
1493 | /* |
1494 | * This and the following assertions are unreliable since we may see jh | |
1495 | * in inconsistent state unless we grab bh_state lock. But this is | |
1496 | * crucial to catch bugs so let's do a reliable check until the | |
1497 | * lockless handling is fully proven. | |
1498 | */ | |
83fe6b18 JK |
1499 | if (data_race(jh->b_transaction != transaction && |
1500 | jh->b_next_transaction != transaction)) { | |
46417064 | 1501 | spin_lock(&jh->b_state_lock); |
6e06ae88 JK |
1502 | J_ASSERT_JH(jh, jh->b_transaction == transaction || |
1503 | jh->b_next_transaction == transaction); | |
46417064 | 1504 | spin_unlock(&jh->b_state_lock); |
6e06ae88 JK |
1505 | } |
1506 | if (jh->b_modified == 1) { | |
1507 | /* If it's in our transaction it must be in BJ_Metadata list. */ | |
83fe6b18 JK |
1508 | if (data_race(jh->b_transaction == transaction && |
1509 | jh->b_jlist != BJ_Metadata)) { | |
46417064 | 1510 | spin_lock(&jh->b_state_lock); |
e09463f2 TT |
1511 | if (jh->b_transaction == transaction && |
1512 | jh->b_jlist != BJ_Metadata) | |
1513 | pr_err("JBD2: assertion failure: h_type=%u " | |
1514 | "h_line_no=%u block_no=%llu jlist=%u\n", | |
1515 | handle->h_type, handle->h_line_no, | |
1516 | (unsigned long long) bh->b_blocknr, | |
1517 | jh->b_jlist); | |
6e06ae88 JK |
1518 | J_ASSERT_JH(jh, jh->b_transaction != transaction || |
1519 | jh->b_jlist == BJ_Metadata); | |
46417064 | 1520 | spin_unlock(&jh->b_state_lock); |
6e06ae88 JK |
1521 | } |
1522 | goto out; | |
1523 | } | |
1524 | ||
1525 | journal = transaction->t_journal; | |
46417064 | 1526 | spin_lock(&jh->b_state_lock); |
470decc6 DK |
1527 | |
1528 | if (jh->b_modified == 0) { | |
1529 | /* | |
1530 | * This buffer's got modified and becoming part | |
1531 | * of the transaction. This needs to be done | |
1532 | * once a transaction -bzzz | |
1533 | */ | |
d090707e | 1534 | if (WARN_ON_ONCE(jbd2_handle_buffer_credits(handle) <= 0)) { |
f6c07cad TT |
1535 | ret = -ENOSPC; |
1536 | goto out_unlock_bh; | |
1537 | } | |
e09463f2 | 1538 | jh->b_modified = 1; |
933f1c1e | 1539 | handle->h_total_credits--; |
470decc6 DK |
1540 | } |
1541 | ||
1542 | /* | |
1543 | * fastpath, to avoid expensive locking. If this buffer is already | |
1544 | * on the running transaction's metadata list there is nothing to do. | |
1545 | * Nobody can take it off again because there is a handle open. | |
1546 | * I _think_ we're OK here with SMP barriers - a mistaken decision will | |
1547 | * result in this test being false, so we go in and take the locks. | |
1548 | */ | |
1549 | if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { | |
1550 | JBUFFER_TRACE(jh, "fastpath"); | |
9ea7a0df TT |
1551 | if (unlikely(jh->b_transaction != |
1552 | journal->j_running_transaction)) { | |
a67c848a | 1553 | printk(KERN_ERR "JBD2: %s: " |
9ea7a0df | 1554 | "jh->b_transaction (%llu, %p, %u) != " |
66a4cb18 | 1555 | "journal->j_running_transaction (%p, %u)\n", |
9ea7a0df TT |
1556 | journal->j_devname, |
1557 | (unsigned long long) bh->b_blocknr, | |
1558 | jh->b_transaction, | |
1559 | jh->b_transaction ? jh->b_transaction->t_tid : 0, | |
1560 | journal->j_running_transaction, | |
1561 | journal->j_running_transaction ? | |
1562 | journal->j_running_transaction->t_tid : 0); | |
1563 | ret = -EINVAL; | |
1564 | } | |
470decc6 DK |
1565 | goto out_unlock_bh; |
1566 | } | |
1567 | ||
1568 | set_buffer_jbddirty(bh); | |
1569 | ||
1570 | /* | |
1571 | * Metadata already on the current transaction list doesn't | |
1572 | * need to be filed. Metadata on another transaction's list must | |
1573 | * be committing, and will be refiled once the commit completes: | |
1574 | * leave it alone for now. | |
1575 | */ | |
1576 | if (jh->b_transaction != transaction) { | |
1577 | JBUFFER_TRACE(jh, "already on other transaction"); | |
66a4cb18 TT |
1578 | if (unlikely(((jh->b_transaction != |
1579 | journal->j_committing_transaction)) || | |
1580 | (jh->b_next_transaction != transaction))) { | |
1581 | printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: " | |
1582 | "bad jh for block %llu: " | |
1583 | "transaction (%p, %u), " | |
1584 | "jh->b_transaction (%p, %u), " | |
1585 | "jh->b_next_transaction (%p, %u), jlist %u\n", | |
9ea7a0df TT |
1586 | journal->j_devname, |
1587 | (unsigned long long) bh->b_blocknr, | |
66a4cb18 | 1588 | transaction, transaction->t_tid, |
9ea7a0df | 1589 | jh->b_transaction, |
66a4cb18 TT |
1590 | jh->b_transaction ? |
1591 | jh->b_transaction->t_tid : 0, | |
9ea7a0df TT |
1592 | jh->b_next_transaction, |
1593 | jh->b_next_transaction ? | |
1594 | jh->b_next_transaction->t_tid : 0, | |
66a4cb18 TT |
1595 | jh->b_jlist); |
1596 | WARN_ON(1); | |
9ea7a0df TT |
1597 | ret = -EINVAL; |
1598 | } | |
470decc6 DK |
1599 | /* And this case is illegal: we can't reuse another |
1600 | * transaction's data buffer, ever. */ | |
1601 | goto out_unlock_bh; | |
1602 | } | |
1603 | ||
1604 | /* That test should have eliminated the following case: */ | |
4019191b | 1605 | J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
470decc6 DK |
1606 | |
1607 | JBUFFER_TRACE(jh, "file as BJ_Metadata"); | |
1608 | spin_lock(&journal->j_list_lock); | |
41a5b913 | 1609 | __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata); |
470decc6 DK |
1610 | spin_unlock(&journal->j_list_lock); |
1611 | out_unlock_bh: | |
46417064 | 1612 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
1613 | out: |
1614 | JBUFFER_TRACE(jh, "exit"); | |
9ea7a0df | 1615 | return ret; |
470decc6 DK |
1616 | } |
1617 | ||
470decc6 | 1618 | /** |
2bf31d94 | 1619 | * jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
470decc6 DK |
1620 | * @handle: transaction handle |
1621 | * @bh: bh to 'forget' | |
1622 | * | |
1623 | * We can only do the bforget if there are no commits pending against the | |
1624 | * buffer. If the buffer is dirty in the current running transaction we | |
1625 | * can safely unlink it. | |
1626 | * | |
1627 | * bh may not be a journalled buffer at all - it may be a non-JBD | |
1628 | * buffer which came off the hashtable. Check for this. | |
1629 | * | |
1630 | * Decrements bh->b_count by one. | |
1631 | * | |
1632 | * Allow this call even if the handle has aborted --- it may be part of | |
1633 | * the caller's cleanup after an abort. | |
1634 | */ | |
8d6ce136 | 1635 | int jbd2_journal_forget(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1636 | { |
1637 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1638 | journal_t *journal; |
470decc6 DK |
1639 | struct journal_head *jh; |
1640 | int drop_reserve = 0; | |
1641 | int err = 0; | |
1dfc3220 | 1642 | int was_modified = 0; |
470decc6 | 1643 | |
41a5b913 TT |
1644 | if (is_handle_aborted(handle)) |
1645 | return -EROFS; | |
1646 | journal = transaction->t_journal; | |
1647 | ||
470decc6 DK |
1648 | BUFFER_TRACE(bh, "entry"); |
1649 | ||
46417064 TG |
1650 | jh = jbd2_journal_grab_journal_head(bh); |
1651 | if (!jh) { | |
1652 | __bforget(bh); | |
1653 | return 0; | |
1654 | } | |
470decc6 | 1655 | |
46417064 | 1656 | spin_lock(&jh->b_state_lock); |
470decc6 DK |
1657 | |
1658 | /* Critical error: attempting to delete a bitmap buffer, maybe? | |
1659 | * Don't do any jbd operations, and return an error. */ | |
1660 | if (!J_EXPECT_JH(jh, !jh->b_committed_data, | |
1661 | "inconsistent data on disk")) { | |
1662 | err = -EIO; | |
2e710ff0 | 1663 | goto drop; |
470decc6 DK |
1664 | } |
1665 | ||
48fc7f7e | 1666 | /* keep track of whether or not this transaction modified us */ |
1dfc3220 JB |
1667 | was_modified = jh->b_modified; |
1668 | ||
470decc6 DK |
1669 | /* |
1670 | * The buffer's going from the transaction, we must drop | |
1671 | * all references -bzzz | |
1672 | */ | |
1673 | jh->b_modified = 0; | |
1674 | ||
41a5b913 | 1675 | if (jh->b_transaction == transaction) { |
470decc6 DK |
1676 | J_ASSERT_JH(jh, !jh->b_frozen_data); |
1677 | ||
1678 | /* If we are forgetting a buffer which is already part | |
1679 | * of this transaction, then we can just drop it from | |
1680 | * the transaction immediately. */ | |
1681 | clear_buffer_dirty(bh); | |
1682 | clear_buffer_jbddirty(bh); | |
1683 | ||
1684 | JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); | |
1685 | ||
1dfc3220 JB |
1686 | /* |
1687 | * we only want to drop a reference if this transaction | |
1688 | * modified the buffer | |
1689 | */ | |
1690 | if (was_modified) | |
1691 | drop_reserve = 1; | |
470decc6 DK |
1692 | |
1693 | /* | |
1694 | * We are no longer going to journal this buffer. | |
1695 | * However, the commit of this transaction is still | |
1696 | * important to the buffer: the delete that we are now | |
1697 | * processing might obsolete an old log entry, so by | |
1698 | * committing, we can satisfy the buffer's checkpoint. | |
1699 | * | |
1700 | * So, if we have a checkpoint on the buffer, we should | |
1701 | * now refile the buffer on our BJ_Forget list so that | |
1702 | * we know to remove the checkpoint after we commit. | |
1703 | */ | |
1704 | ||
0bfea811 | 1705 | spin_lock(&journal->j_list_lock); |
470decc6 | 1706 | if (jh->b_cp_transaction) { |
f7f4bccb MC |
1707 | __jbd2_journal_temp_unlink_buffer(jh); |
1708 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
470decc6 | 1709 | } else { |
f7f4bccb | 1710 | __jbd2_journal_unfile_buffer(jh); |
93108ebb | 1711 | jbd2_journal_put_journal_head(jh); |
470decc6 | 1712 | } |
0bfea811 | 1713 | spin_unlock(&journal->j_list_lock); |
470decc6 DK |
1714 | } else if (jh->b_transaction) { |
1715 | J_ASSERT_JH(jh, (jh->b_transaction == | |
1716 | journal->j_committing_transaction)); | |
1717 | /* However, if the buffer is still owned by a prior | |
1718 | * (committing) transaction, we can't drop it yet... */ | |
1719 | JBUFFER_TRACE(jh, "belongs to older transaction"); | |
904cdbd4 | 1720 | /* ... but we CAN drop it from the new transaction through |
1721 | * marking the buffer as freed and set j_next_transaction to | |
1722 | * the new transaction, so that not only the commit code | |
1723 | * knows it should clear dirty bits when it is done with the | |
1724 | * buffer, but also the buffer can be checkpointed only | |
1725 | * after the new transaction commits. */ | |
470decc6 | 1726 | |
904cdbd4 | 1727 | set_buffer_freed(bh); |
1728 | ||
1729 | if (!jh->b_next_transaction) { | |
0bfea811 | 1730 | spin_lock(&journal->j_list_lock); |
904cdbd4 | 1731 | jh->b_next_transaction = transaction; |
0bfea811 | 1732 | spin_unlock(&journal->j_list_lock); |
904cdbd4 | 1733 | } else { |
1734 | J_ASSERT(jh->b_next_transaction == transaction); | |
1dfc3220 JB |
1735 | |
1736 | /* | |
1737 | * only drop a reference if this transaction modified | |
1738 | * the buffer | |
1739 | */ | |
1740 | if (was_modified) | |
1741 | drop_reserve = 1; | |
470decc6 | 1742 | } |
59759926 | 1743 | } else { |
1744 | /* | |
1745 | * Finally, if the buffer is not belongs to any | |
1746 | * transaction, we can just drop it now if it has no | |
1747 | * checkpoint. | |
1748 | */ | |
1749 | spin_lock(&journal->j_list_lock); | |
1750 | if (!jh->b_cp_transaction) { | |
1751 | JBUFFER_TRACE(jh, "belongs to none transaction"); | |
1752 | spin_unlock(&journal->j_list_lock); | |
2e710ff0 | 1753 | goto drop; |
59759926 | 1754 | } |
1755 | ||
1756 | /* | |
1757 | * Otherwise, if the buffer has been written to disk, | |
1758 | * it is safe to remove the checkpoint and drop it. | |
1759 | */ | |
1760 | if (!buffer_dirty(bh)) { | |
1761 | __jbd2_journal_remove_checkpoint(jh); | |
1762 | spin_unlock(&journal->j_list_lock); | |
2e710ff0 | 1763 | goto drop; |
59759926 | 1764 | } |
1765 | ||
1766 | /* | |
1767 | * The buffer is still not written to disk, we should | |
1768 | * attach this buffer to current transaction so that the | |
1769 | * buffer can be checkpointed only after the current | |
1770 | * transaction commits. | |
1771 | */ | |
1772 | clear_buffer_dirty(bh); | |
1773 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
1774 | spin_unlock(&journal->j_list_lock); | |
470decc6 | 1775 | } |
470decc6 | 1776 | drop: |
470decc6 | 1777 | __brelse(bh); |
46417064 TG |
1778 | spin_unlock(&jh->b_state_lock); |
1779 | jbd2_journal_put_journal_head(jh); | |
470decc6 DK |
1780 | if (drop_reserve) { |
1781 | /* no need to reserve log space for this block -bzzz */ | |
933f1c1e | 1782 | handle->h_total_credits++; |
470decc6 DK |
1783 | } |
1784 | return err; | |
1785 | } | |
1786 | ||
1787 | /** | |
2bf31d94 | 1788 | * jbd2_journal_stop() - complete a transaction |
bd7ced98 | 1789 | * @handle: transaction to complete. |
470decc6 DK |
1790 | * |
1791 | * All done for a particular handle. | |
1792 | * | |
1793 | * There is not much action needed here. We just return any remaining | |
1794 | * buffer credits to the transaction and remove the handle. The only | |
1795 | * complication is that we need to start a commit operation if the | |
1796 | * filesystem is marked for synchronous update. | |
1797 | * | |
f7f4bccb | 1798 | * jbd2_journal_stop itself will not usually return an error, but it may |
470decc6 | 1799 | * do so in unusual circumstances. In particular, expect it to |
f7f4bccb | 1800 | * return -EIO if a jbd2_journal_abort has been executed since the |
470decc6 DK |
1801 | * transaction began. |
1802 | */ | |
f7f4bccb | 1803 | int jbd2_journal_stop(handle_t *handle) |
470decc6 DK |
1804 | { |
1805 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 TT |
1806 | journal_t *journal; |
1807 | int err = 0, wait_for_commit = 0; | |
a51dca9c | 1808 | tid_t tid; |
470decc6 DK |
1809 | pid_t pid; |
1810 | ||
dfaf5ffd JK |
1811 | if (--handle->h_ref > 0) { |
1812 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1813 | handle->h_ref); | |
1814 | if (is_handle_aborted(handle)) | |
1815 | return -EIO; | |
1816 | return 0; | |
1817 | } | |
9d506594 LC |
1818 | if (!transaction) { |
1819 | /* | |
dfaf5ffd JK |
1820 | * Handle is already detached from the transaction so there is |
1821 | * nothing to do other than free the handle. | |
9d506594 | 1822 | */ |
ec8b6f60 | 1823 | memalloc_nofs_restore(handle->saved_alloc_context); |
dfaf5ffd | 1824 | goto free_and_exit; |
9d506594 | 1825 | } |
41a5b913 | 1826 | journal = transaction->t_journal; |
dfaf5ffd | 1827 | tid = transaction->t_tid; |
470decc6 DK |
1828 | |
1829 | if (is_handle_aborted(handle)) | |
1830 | err = -EIO; | |
470decc6 DK |
1831 | |
1832 | jbd_debug(4, "Handle %p going down\n", handle); | |
343d9c28 | 1833 | trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev, |
dfaf5ffd | 1834 | tid, handle->h_type, handle->h_line_no, |
343d9c28 TT |
1835 | jiffies - handle->h_start_jiffies, |
1836 | handle->h_sync, handle->h_requested_credits, | |
1837 | (handle->h_requested_credits - | |
933f1c1e | 1838 | handle->h_total_credits)); |
470decc6 DK |
1839 | |
1840 | /* | |
1841 | * Implement synchronous transaction batching. If the handle | |
1842 | * was synchronous, don't force a commit immediately. Let's | |
e07f7183 JB |
1843 | * yield and let another thread piggyback onto this |
1844 | * transaction. Keep doing that while new threads continue to | |
1845 | * arrive. It doesn't cost much - we're about to run a commit | |
1846 | * and sleep on IO anyway. Speeds up many-threaded, many-dir | |
1847 | * operations by 30x or more... | |
1848 | * | |
1849 | * We try and optimize the sleep time against what the | |
1850 | * underlying disk can do, instead of having a static sleep | |
1851 | * time. This is useful for the case where our storage is so | |
1852 | * fast that it is more optimal to go ahead and force a flush | |
1853 | * and wait for the transaction to be committed than it is to | |
1854 | * wait for an arbitrary amount of time for new writers to | |
1855 | * join the transaction. We achieve this by measuring how | |
1856 | * long it takes to commit a transaction, and compare it with | |
1857 | * how long this transaction has been running, and if run time | |
1858 | * < commit time then we sleep for the delta and commit. This | |
1859 | * greatly helps super fast disks that would see slowdowns as | |
1860 | * more threads started doing fsyncs. | |
470decc6 | 1861 | * |
e07f7183 JB |
1862 | * But don't do this if this process was the most recent one |
1863 | * to perform a synchronous write. We do this to detect the | |
1864 | * case where a single process is doing a stream of sync | |
1865 | * writes. No point in waiting for joiners in that case. | |
5dd21424 ES |
1866 | * |
1867 | * Setting max_batch_time to 0 disables this completely. | |
470decc6 DK |
1868 | */ |
1869 | pid = current->pid; | |
5dd21424 ES |
1870 | if (handle->h_sync && journal->j_last_sync_writer != pid && |
1871 | journal->j_max_batch_time) { | |
e07f7183 JB |
1872 | u64 commit_time, trans_time; |
1873 | ||
470decc6 | 1874 | journal->j_last_sync_writer = pid; |
e07f7183 | 1875 | |
a931da6a | 1876 | read_lock(&journal->j_state_lock); |
e07f7183 | 1877 | commit_time = journal->j_average_commit_time; |
a931da6a | 1878 | read_unlock(&journal->j_state_lock); |
e07f7183 JB |
1879 | |
1880 | trans_time = ktime_to_ns(ktime_sub(ktime_get(), | |
1881 | transaction->t_start_time)); | |
1882 | ||
30773840 TT |
1883 | commit_time = max_t(u64, commit_time, |
1884 | 1000*journal->j_min_batch_time); | |
e07f7183 | 1885 | commit_time = min_t(u64, commit_time, |
30773840 | 1886 | 1000*journal->j_max_batch_time); |
e07f7183 JB |
1887 | |
1888 | if (trans_time < commit_time) { | |
1889 | ktime_t expires = ktime_add_ns(ktime_get(), | |
1890 | commit_time); | |
1891 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1892 | schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); | |
1893 | } | |
470decc6 DK |
1894 | } |
1895 | ||
7058548c TT |
1896 | if (handle->h_sync) |
1897 | transaction->t_synchronous_commit = 1; | |
470decc6 DK |
1898 | |
1899 | /* | |
1900 | * If the handle is marked SYNC, we need to set another commit | |
150549ed JK |
1901 | * going! We also want to force a commit if the transaction is too |
1902 | * old now. | |
470decc6 DK |
1903 | */ |
1904 | if (handle->h_sync || | |
a51dca9c | 1905 | time_after_eq(jiffies, transaction->t_expires)) { |
470decc6 DK |
1906 | /* Do this even for aborted journals: an abort still |
1907 | * completes the commit thread, it just doesn't write | |
1908 | * anything to disk. */ | |
470decc6 | 1909 | |
470decc6 DK |
1910 | jbd_debug(2, "transaction too old, requesting commit for " |
1911 | "handle %p\n", handle); | |
1912 | /* This is non-blocking */ | |
dfaf5ffd | 1913 | jbd2_log_start_commit(journal, tid); |
470decc6 DK |
1914 | |
1915 | /* | |
f7f4bccb | 1916 | * Special case: JBD2_SYNC synchronous updates require us |
470decc6 DK |
1917 | * to wait for the commit to complete. |
1918 | */ | |
1919 | if (handle->h_sync && !(current->flags & PF_MEMALLOC)) | |
a51dca9c | 1920 | wait_for_commit = 1; |
470decc6 DK |
1921 | } |
1922 | ||
a51dca9c | 1923 | /* |
ec8b6f60 JK |
1924 | * Once stop_this_handle() drops t_updates, the transaction could start |
1925 | * committing on us and eventually disappear. So we must not | |
1926 | * dereference transaction pointer again after calling | |
1927 | * stop_this_handle(). | |
a51dca9c | 1928 | */ |
ec8b6f60 | 1929 | stop_this_handle(handle); |
7a4b188f | 1930 | |
a51dca9c TT |
1931 | if (wait_for_commit) |
1932 | err = jbd2_log_wait_commit(journal, tid); | |
1933 | ||
41a5b913 | 1934 | free_and_exit: |
ec8b6f60 JK |
1935 | if (handle->h_rsv_handle) |
1936 | jbd2_free_handle(handle->h_rsv_handle); | |
af1e76d6 | 1937 | jbd2_free_handle(handle); |
470decc6 DK |
1938 | return err; |
1939 | } | |
1940 | ||
470decc6 DK |
1941 | /* |
1942 | * | |
1943 | * List management code snippets: various functions for manipulating the | |
1944 | * transaction buffer lists. | |
1945 | * | |
1946 | */ | |
1947 | ||
1948 | /* | |
1949 | * Append a buffer to a transaction list, given the transaction's list head | |
1950 | * pointer. | |
1951 | * | |
1952 | * j_list_lock is held. | |
1953 | * | |
46417064 | 1954 | * jh->b_state_lock is held. |
470decc6 DK |
1955 | */ |
1956 | ||
1957 | static inline void | |
1958 | __blist_add_buffer(struct journal_head **list, struct journal_head *jh) | |
1959 | { | |
1960 | if (!*list) { | |
1961 | jh->b_tnext = jh->b_tprev = jh; | |
1962 | *list = jh; | |
1963 | } else { | |
1964 | /* Insert at the tail of the list to preserve order */ | |
1965 | struct journal_head *first = *list, *last = first->b_tprev; | |
1966 | jh->b_tprev = last; | |
1967 | jh->b_tnext = first; | |
1968 | last->b_tnext = first->b_tprev = jh; | |
1969 | } | |
1970 | } | |
1971 | ||
1972 | /* | |
1973 | * Remove a buffer from a transaction list, given the transaction's list | |
1974 | * head pointer. | |
1975 | * | |
1976 | * Called with j_list_lock held, and the journal may not be locked. | |
1977 | * | |
46417064 | 1978 | * jh->b_state_lock is held. |
470decc6 DK |
1979 | */ |
1980 | ||
1981 | static inline void | |
1982 | __blist_del_buffer(struct journal_head **list, struct journal_head *jh) | |
1983 | { | |
1984 | if (*list == jh) { | |
1985 | *list = jh->b_tnext; | |
1986 | if (*list == jh) | |
1987 | *list = NULL; | |
1988 | } | |
1989 | jh->b_tprev->b_tnext = jh->b_tnext; | |
1990 | jh->b_tnext->b_tprev = jh->b_tprev; | |
1991 | } | |
1992 | ||
1993 | /* | |
1994 | * Remove a buffer from the appropriate transaction list. | |
1995 | * | |
1996 | * Note that this function can *change* the value of | |
f5113eff JK |
1997 | * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or |
1998 | * t_reserved_list. If the caller is holding onto a copy of one of these | |
1999 | * pointers, it could go bad. Generally the caller needs to re-read the | |
2000 | * pointer from the transaction_t. | |
470decc6 | 2001 | * |
5bebccf9 | 2002 | * Called under j_list_lock. |
470decc6 | 2003 | */ |
5bebccf9 | 2004 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
470decc6 DK |
2005 | { |
2006 | struct journal_head **list = NULL; | |
2007 | transaction_t *transaction; | |
2008 | struct buffer_head *bh = jh2bh(jh); | |
2009 | ||
46417064 | 2010 | lockdep_assert_held(&jh->b_state_lock); |
470decc6 DK |
2011 | transaction = jh->b_transaction; |
2012 | if (transaction) | |
2013 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
2014 | ||
2015 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
2016 | if (jh->b_jlist != BJ_None) | |
4019191b | 2017 | J_ASSERT_JH(jh, transaction != NULL); |
470decc6 DK |
2018 | |
2019 | switch (jh->b_jlist) { | |
2020 | case BJ_None: | |
2021 | return; | |
470decc6 DK |
2022 | case BJ_Metadata: |
2023 | transaction->t_nr_buffers--; | |
2024 | J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); | |
2025 | list = &transaction->t_buffers; | |
2026 | break; | |
2027 | case BJ_Forget: | |
2028 | list = &transaction->t_forget; | |
2029 | break; | |
470decc6 DK |
2030 | case BJ_Shadow: |
2031 | list = &transaction->t_shadow_list; | |
2032 | break; | |
470decc6 DK |
2033 | case BJ_Reserved: |
2034 | list = &transaction->t_reserved_list; | |
2035 | break; | |
470decc6 DK |
2036 | } |
2037 | ||
2038 | __blist_del_buffer(list, jh); | |
2039 | jh->b_jlist = BJ_None; | |
e112666b TT |
2040 | if (transaction && is_journal_aborted(transaction->t_journal)) |
2041 | clear_buffer_jbddirty(bh); | |
2042 | else if (test_clear_buffer_jbddirty(bh)) | |
470decc6 DK |
2043 | mark_buffer_dirty(bh); /* Expose it to the VM */ |
2044 | } | |
2045 | ||
de1b7941 | 2046 | /* |
93108ebb JK |
2047 | * Remove buffer from all transactions. The caller is responsible for dropping |
2048 | * the jh reference that belonged to the transaction. | |
de1b7941 JK |
2049 | * |
2050 | * Called with bh_state lock and j_list_lock | |
de1b7941 JK |
2051 | */ |
2052 | static void __jbd2_journal_unfile_buffer(struct journal_head *jh) | |
470decc6 | 2053 | { |
24dc9864 LC |
2054 | J_ASSERT_JH(jh, jh->b_transaction != NULL); |
2055 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
2056 | ||
f7f4bccb | 2057 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 DK |
2058 | jh->b_transaction = NULL; |
2059 | } | |
2060 | ||
f7f4bccb | 2061 | void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 | 2062 | { |
de1b7941 JK |
2063 | struct buffer_head *bh = jh2bh(jh); |
2064 | ||
2065 | /* Get reference so that buffer cannot be freed before we unlock it */ | |
2066 | get_bh(bh); | |
46417064 | 2067 | spin_lock(&jh->b_state_lock); |
470decc6 | 2068 | spin_lock(&journal->j_list_lock); |
f7f4bccb | 2069 | __jbd2_journal_unfile_buffer(jh); |
470decc6 | 2070 | spin_unlock(&journal->j_list_lock); |
46417064 | 2071 | spin_unlock(&jh->b_state_lock); |
93108ebb | 2072 | jbd2_journal_put_journal_head(jh); |
de1b7941 | 2073 | __brelse(bh); |
470decc6 DK |
2074 | } |
2075 | ||
2076 | /* | |
f7f4bccb | 2077 | * Called from jbd2_journal_try_to_free_buffers(). |
470decc6 | 2078 | * |
46417064 | 2079 | * Called under jh->b_state_lock |
470decc6 DK |
2080 | */ |
2081 | static void | |
2082 | __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) | |
2083 | { | |
2084 | struct journal_head *jh; | |
2085 | ||
2086 | jh = bh2jh(bh); | |
2087 | ||
2088 | if (buffer_locked(bh) || buffer_dirty(bh)) | |
2089 | goto out; | |
2090 | ||
d2eb0b99 | 2091 | if (jh->b_next_transaction != NULL || jh->b_transaction != NULL) |
470decc6 DK |
2092 | goto out; |
2093 | ||
2094 | spin_lock(&journal->j_list_lock); | |
d2eb0b99 | 2095 | if (jh->b_cp_transaction != NULL) { |
470decc6 | 2096 | /* written-back checkpointed metadata buffer */ |
c254c9ec JK |
2097 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
2098 | __jbd2_journal_remove_checkpoint(jh); | |
470decc6 DK |
2099 | } |
2100 | spin_unlock(&journal->j_list_lock); | |
2101 | out: | |
2102 | return; | |
2103 | } | |
2104 | ||
470decc6 | 2105 | /** |
2bf31d94 | 2106 | * jbd2_journal_try_to_free_buffers() - try to free page buffers. |
470decc6 DK |
2107 | * @journal: journal for operation |
2108 | * @page: to try and free | |
470decc6 DK |
2109 | * |
2110 | * For all the buffers on this page, | |
2111 | * if they are fully written out ordered data, move them onto BUF_CLEAN | |
2112 | * so try_to_free_buffers() can reap them. | |
2113 | * | |
2114 | * This function returns non-zero if we wish try_to_free_buffers() | |
2115 | * to be called. We do this if the page is releasable by try_to_free_buffers(). | |
2116 | * We also do it if the page has locked or dirty buffers and the caller wants | |
2117 | * us to perform sync or async writeout. | |
2118 | * | |
2119 | * This complicates JBD locking somewhat. We aren't protected by the | |
2120 | * BKL here. We wish to remove the buffer from its committing or | |
f7f4bccb | 2121 | * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
470decc6 DK |
2122 | * |
2123 | * This may *change* the value of transaction_t->t_datalist, so anyone | |
2124 | * who looks at t_datalist needs to lock against this function. | |
2125 | * | |
f7f4bccb MC |
2126 | * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
2127 | * buffer. So we need to lock against that. jbd2_journal_dirty_data() | |
470decc6 DK |
2128 | * will come out of the lock with the buffer dirty, which makes it |
2129 | * ineligible for release here. | |
2130 | * | |
2131 | * Who else is affected by this? hmm... Really the only contender | |
2132 | * is do_get_write_access() - it could be looking at the buffer while | |
2133 | * journal_try_to_free_buffer() is changing its state. But that | |
2134 | * cannot happen because we never reallocate freed data as metadata | |
2135 | * while the data is part of a transaction. Yes? | |
530576bb MC |
2136 | * |
2137 | * Return 0 on failure, 1 on success | |
470decc6 | 2138 | */ |
529a781e | 2139 | int jbd2_journal_try_to_free_buffers(journal_t *journal, struct page *page) |
470decc6 DK |
2140 | { |
2141 | struct buffer_head *head; | |
2142 | struct buffer_head *bh; | |
2143 | int ret = 0; | |
2144 | ||
2145 | J_ASSERT(PageLocked(page)); | |
2146 | ||
2147 | head = page_buffers(page); | |
2148 | bh = head; | |
2149 | do { | |
2150 | struct journal_head *jh; | |
2151 | ||
2152 | /* | |
2153 | * We take our own ref against the journal_head here to avoid | |
2154 | * having to add tons of locking around each instance of | |
530576bb | 2155 | * jbd2_journal_put_journal_head(). |
470decc6 | 2156 | */ |
f7f4bccb | 2157 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
2158 | if (!jh) |
2159 | continue; | |
2160 | ||
46417064 | 2161 | spin_lock(&jh->b_state_lock); |
470decc6 | 2162 | __journal_try_to_free_buffer(journal, bh); |
46417064 | 2163 | spin_unlock(&jh->b_state_lock); |
f7f4bccb | 2164 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2165 | if (buffer_jbd(bh)) |
2166 | goto busy; | |
2167 | } while ((bh = bh->b_this_page) != head); | |
530576bb | 2168 | |
470decc6 DK |
2169 | ret = try_to_free_buffers(page); |
2170 | busy: | |
2171 | return ret; | |
2172 | } | |
2173 | ||
2174 | /* | |
2175 | * This buffer is no longer needed. If it is on an older transaction's | |
2176 | * checkpoint list we need to record it on this transaction's forget list | |
2177 | * to pin this buffer (and hence its checkpointing transaction) down until | |
2178 | * this transaction commits. If the buffer isn't on a checkpoint list, we | |
2179 | * release it. | |
2180 | * Returns non-zero if JBD no longer has an interest in the buffer. | |
2181 | * | |
2182 | * Called under j_list_lock. | |
2183 | * | |
46417064 | 2184 | * Called under jh->b_state_lock. |
470decc6 DK |
2185 | */ |
2186 | static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) | |
2187 | { | |
2188 | int may_free = 1; | |
2189 | struct buffer_head *bh = jh2bh(jh); | |
2190 | ||
470decc6 DK |
2191 | if (jh->b_cp_transaction) { |
2192 | JBUFFER_TRACE(jh, "on running+cp transaction"); | |
de1b7941 | 2193 | __jbd2_journal_temp_unlink_buffer(jh); |
f91d1d04 JK |
2194 | /* |
2195 | * We don't want to write the buffer anymore, clear the | |
2196 | * bit so that we don't confuse checks in | |
2197 | * __journal_file_buffer | |
2198 | */ | |
2199 | clear_buffer_dirty(bh); | |
f7f4bccb | 2200 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
470decc6 DK |
2201 | may_free = 0; |
2202 | } else { | |
2203 | JBUFFER_TRACE(jh, "on running transaction"); | |
de1b7941 | 2204 | __jbd2_journal_unfile_buffer(jh); |
93108ebb | 2205 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2206 | } |
2207 | return may_free; | |
2208 | } | |
2209 | ||
2210 | /* | |
f7f4bccb | 2211 | * jbd2_journal_invalidatepage |
470decc6 DK |
2212 | * |
2213 | * This code is tricky. It has a number of cases to deal with. | |
2214 | * | |
2215 | * There are two invariants which this code relies on: | |
2216 | * | |
2217 | * i_size must be updated on disk before we start calling invalidatepage on the | |
2218 | * data. | |
2219 | * | |
2220 | * This is done in ext3 by defining an ext3_setattr method which | |
2221 | * updates i_size before truncate gets going. By maintaining this | |
2222 | * invariant, we can be sure that it is safe to throw away any buffers | |
2223 | * attached to the current transaction: once the transaction commits, | |
2224 | * we know that the data will not be needed. | |
2225 | * | |
2226 | * Note however that we can *not* throw away data belonging to the | |
2227 | * previous, committing transaction! | |
2228 | * | |
2229 | * Any disk blocks which *are* part of the previous, committing | |
2230 | * transaction (and which therefore cannot be discarded immediately) are | |
2231 | * not going to be reused in the new running transaction | |
2232 | * | |
2233 | * The bitmap committed_data images guarantee this: any block which is | |
2234 | * allocated in one transaction and removed in the next will be marked | |
2235 | * as in-use in the committed_data bitmap, so cannot be reused until | |
2236 | * the next transaction to delete the block commits. This means that | |
2237 | * leaving committing buffers dirty is quite safe: the disk blocks | |
2238 | * cannot be reallocated to a different file and so buffer aliasing is | |
2239 | * not possible. | |
2240 | * | |
2241 | * | |
2242 | * The above applies mainly to ordered data mode. In writeback mode we | |
2243 | * don't make guarantees about the order in which data hits disk --- in | |
2244 | * particular we don't guarantee that new dirty data is flushed before | |
2245 | * transaction commit --- so it is always safe just to discard data | |
2246 | * immediately in that mode. --sct | |
2247 | */ | |
2248 | ||
2249 | /* | |
2250 | * The journal_unmap_buffer helper function returns zero if the buffer | |
2251 | * concerned remains pinned as an anonymous buffer belonging to an older | |
2252 | * transaction. | |
2253 | * | |
2254 | * We're outside-transaction here. Either or both of j_running_transaction | |
2255 | * and j_committing_transaction may be NULL. | |
2256 | */ | |
b794e7a6 JK |
2257 | static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, |
2258 | int partial_page) | |
470decc6 DK |
2259 | { |
2260 | transaction_t *transaction; | |
2261 | struct journal_head *jh; | |
2262 | int may_free = 1; | |
470decc6 DK |
2263 | |
2264 | BUFFER_TRACE(bh, "entry"); | |
2265 | ||
2266 | /* | |
2267 | * It is safe to proceed here without the j_list_lock because the | |
2268 | * buffers cannot be stolen by try_to_free_buffers as long as we are | |
2269 | * holding the page lock. --sct | |
2270 | */ | |
2271 | ||
d84560f7 TG |
2272 | jh = jbd2_journal_grab_journal_head(bh); |
2273 | if (!jh) | |
470decc6 DK |
2274 | goto zap_buffer_unlocked; |
2275 | ||
87c89c23 | 2276 | /* OK, we have data buffer in journaled mode */ |
a931da6a | 2277 | write_lock(&journal->j_state_lock); |
46417064 | 2278 | spin_lock(&jh->b_state_lock); |
470decc6 DK |
2279 | spin_lock(&journal->j_list_lock); |
2280 | ||
ba869023 | 2281 | /* |
2282 | * We cannot remove the buffer from checkpoint lists until the | |
2283 | * transaction adding inode to orphan list (let's call it T) | |
2284 | * is committed. Otherwise if the transaction changing the | |
2285 | * buffer would be cleaned from the journal before T is | |
2286 | * committed, a crash will cause that the correct contents of | |
2287 | * the buffer will be lost. On the other hand we have to | |
2288 | * clear the buffer dirty bit at latest at the moment when the | |
2289 | * transaction marking the buffer as freed in the filesystem | |
2290 | * structures is committed because from that moment on the | |
b794e7a6 | 2291 | * block can be reallocated and used by a different page. |
ba869023 | 2292 | * Since the block hasn't been freed yet but the inode has |
2293 | * already been added to orphan list, it is safe for us to add | |
2294 | * the buffer to BJ_Forget list of the newest transaction. | |
b794e7a6 JK |
2295 | * |
2296 | * Also we have to clear buffer_mapped flag of a truncated buffer | |
2297 | * because the buffer_head may be attached to the page straddling | |
2298 | * i_size (can happen only when blocksize < pagesize) and thus the | |
2299 | * buffer_head can be reused when the file is extended again. So we end | |
2300 | * up keeping around invalidated buffers attached to transactions' | |
2301 | * BJ_Forget list just to stop checkpointing code from cleaning up | |
2302 | * the transaction this buffer was modified in. | |
ba869023 | 2303 | */ |
470decc6 DK |
2304 | transaction = jh->b_transaction; |
2305 | if (transaction == NULL) { | |
2306 | /* First case: not on any transaction. If it | |
2307 | * has no checkpoint link, then we can zap it: | |
2308 | * it's a writeback-mode buffer so we don't care | |
2309 | * if it hits disk safely. */ | |
2310 | if (!jh->b_cp_transaction) { | |
2311 | JBUFFER_TRACE(jh, "not on any transaction: zap"); | |
2312 | goto zap_buffer; | |
2313 | } | |
2314 | ||
2315 | if (!buffer_dirty(bh)) { | |
2316 | /* bdflush has written it. We can drop it now */ | |
bc23f0c8 | 2317 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
2318 | goto zap_buffer; |
2319 | } | |
2320 | ||
2321 | /* OK, it must be in the journal but still not | |
2322 | * written fully to disk: it's metadata or | |
2323 | * journaled data... */ | |
2324 | ||
2325 | if (journal->j_running_transaction) { | |
2326 | /* ... and once the current transaction has | |
2327 | * committed, the buffer won't be needed any | |
2328 | * longer. */ | |
2329 | JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); | |
b794e7a6 | 2330 | may_free = __dispose_buffer(jh, |
470decc6 | 2331 | journal->j_running_transaction); |
b794e7a6 | 2332 | goto zap_buffer; |
470decc6 DK |
2333 | } else { |
2334 | /* There is no currently-running transaction. So the | |
2335 | * orphan record which we wrote for this file must have | |
2336 | * passed into commit. We must attach this buffer to | |
2337 | * the committing transaction, if it exists. */ | |
2338 | if (journal->j_committing_transaction) { | |
2339 | JBUFFER_TRACE(jh, "give to committing trans"); | |
b794e7a6 | 2340 | may_free = __dispose_buffer(jh, |
470decc6 | 2341 | journal->j_committing_transaction); |
b794e7a6 | 2342 | goto zap_buffer; |
470decc6 DK |
2343 | } else { |
2344 | /* The orphan record's transaction has | |
2345 | * committed. We can cleanse this buffer */ | |
2346 | clear_buffer_jbddirty(bh); | |
bc23f0c8 | 2347 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
2348 | goto zap_buffer; |
2349 | } | |
2350 | } | |
2351 | } else if (transaction == journal->j_committing_transaction) { | |
9b57988d | 2352 | JBUFFER_TRACE(jh, "on committing transaction"); |
470decc6 | 2353 | /* |
ba869023 | 2354 | * The buffer is committing, we simply cannot touch |
b794e7a6 JK |
2355 | * it. If the page is straddling i_size we have to wait |
2356 | * for commit and try again. | |
2357 | */ | |
2358 | if (partial_page) { | |
b794e7a6 | 2359 | spin_unlock(&journal->j_list_lock); |
46417064 | 2360 | spin_unlock(&jh->b_state_lock); |
b794e7a6 | 2361 | write_unlock(&journal->j_state_lock); |
46417064 | 2362 | jbd2_journal_put_journal_head(jh); |
53e87268 | 2363 | return -EBUSY; |
b794e7a6 JK |
2364 | } |
2365 | /* | |
6a66a7de | 2366 | * OK, buffer won't be reachable after truncate. We just clear |
2367 | * b_modified to not confuse transaction credit accounting, and | |
2368 | * set j_next_transaction to the running transaction (if there | |
2369 | * is one) and mark buffer as freed so that commit code knows | |
2370 | * it should clear dirty bits when it is done with the buffer. | |
ba869023 | 2371 | */ |
470decc6 | 2372 | set_buffer_freed(bh); |
ba869023 | 2373 | if (journal->j_running_transaction && buffer_jbddirty(bh)) |
2374 | jh->b_next_transaction = journal->j_running_transaction; | |
6a66a7de | 2375 | jh->b_modified = 0; |
470decc6 | 2376 | spin_unlock(&journal->j_list_lock); |
46417064 | 2377 | spin_unlock(&jh->b_state_lock); |
a931da6a | 2378 | write_unlock(&journal->j_state_lock); |
46417064 | 2379 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2380 | return 0; |
2381 | } else { | |
2382 | /* Good, the buffer belongs to the running transaction. | |
2383 | * We are writing our own transaction's data, not any | |
2384 | * previous one's, so it is safe to throw it away | |
2385 | * (remember that we expect the filesystem to have set | |
2386 | * i_size already for this truncate so recovery will not | |
2387 | * expose the disk blocks we are discarding here.) */ | |
2388 | J_ASSERT_JH(jh, transaction == journal->j_running_transaction); | |
9b57988d | 2389 | JBUFFER_TRACE(jh, "on running transaction"); |
470decc6 DK |
2390 | may_free = __dispose_buffer(jh, transaction); |
2391 | } | |
2392 | ||
2393 | zap_buffer: | |
b794e7a6 JK |
2394 | /* |
2395 | * This is tricky. Although the buffer is truncated, it may be reused | |
2396 | * if blocksize < pagesize and it is attached to the page straddling | |
2397 | * EOF. Since the buffer might have been added to BJ_Forget list of the | |
2398 | * running transaction, journal_get_write_access() won't clear | |
2399 | * b_modified and credit accounting gets confused. So clear b_modified | |
2400 | * here. | |
2401 | */ | |
2402 | jh->b_modified = 0; | |
470decc6 | 2403 | spin_unlock(&journal->j_list_lock); |
46417064 | 2404 | spin_unlock(&jh->b_state_lock); |
a931da6a | 2405 | write_unlock(&journal->j_state_lock); |
46417064 | 2406 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2407 | zap_buffer_unlocked: |
2408 | clear_buffer_dirty(bh); | |
2409 | J_ASSERT_BH(bh, !buffer_jbddirty(bh)); | |
2410 | clear_buffer_mapped(bh); | |
2411 | clear_buffer_req(bh); | |
2412 | clear_buffer_new(bh); | |
15291164 ES |
2413 | clear_buffer_delay(bh); |
2414 | clear_buffer_unwritten(bh); | |
470decc6 DK |
2415 | bh->b_bdev = NULL; |
2416 | return may_free; | |
2417 | } | |
2418 | ||
2419 | /** | |
2bf31d94 | 2420 | * jbd2_journal_invalidatepage() |
470decc6 DK |
2421 | * @journal: journal to use for flush... |
2422 | * @page: page to flush | |
259709b0 LC |
2423 | * @offset: start of the range to invalidate |
2424 | * @length: length of the range to invalidate | |
470decc6 | 2425 | * |
259709b0 LC |
2426 | * Reap page buffers containing data after in the specified range in page. |
2427 | * Can return -EBUSY if buffers are part of the committing transaction and | |
2428 | * the page is straddling i_size. Caller then has to wait for current commit | |
2429 | * and try again. | |
470decc6 | 2430 | */ |
53e87268 JK |
2431 | int jbd2_journal_invalidatepage(journal_t *journal, |
2432 | struct page *page, | |
259709b0 LC |
2433 | unsigned int offset, |
2434 | unsigned int length) | |
470decc6 DK |
2435 | { |
2436 | struct buffer_head *head, *bh, *next; | |
259709b0 | 2437 | unsigned int stop = offset + length; |
470decc6 | 2438 | unsigned int curr_off = 0; |
09cbfeaf | 2439 | int partial_page = (offset || length < PAGE_SIZE); |
470decc6 | 2440 | int may_free = 1; |
53e87268 | 2441 | int ret = 0; |
470decc6 DK |
2442 | |
2443 | if (!PageLocked(page)) | |
2444 | BUG(); | |
2445 | if (!page_has_buffers(page)) | |
53e87268 | 2446 | return 0; |
470decc6 | 2447 | |
09cbfeaf | 2448 | BUG_ON(stop > PAGE_SIZE || stop < length); |
259709b0 | 2449 | |
470decc6 DK |
2450 | /* We will potentially be playing with lists other than just the |
2451 | * data lists (especially for journaled data mode), so be | |
2452 | * cautious in our locking. */ | |
2453 | ||
2454 | head = bh = page_buffers(page); | |
2455 | do { | |
2456 | unsigned int next_off = curr_off + bh->b_size; | |
2457 | next = bh->b_this_page; | |
2458 | ||
259709b0 LC |
2459 | if (next_off > stop) |
2460 | return 0; | |
2461 | ||
470decc6 DK |
2462 | if (offset <= curr_off) { |
2463 | /* This block is wholly outside the truncation point */ | |
2464 | lock_buffer(bh); | |
259709b0 | 2465 | ret = journal_unmap_buffer(journal, bh, partial_page); |
470decc6 | 2466 | unlock_buffer(bh); |
53e87268 JK |
2467 | if (ret < 0) |
2468 | return ret; | |
2469 | may_free &= ret; | |
470decc6 DK |
2470 | } |
2471 | curr_off = next_off; | |
2472 | bh = next; | |
2473 | ||
2474 | } while (bh != head); | |
2475 | ||
259709b0 | 2476 | if (!partial_page) { |
470decc6 DK |
2477 | if (may_free && try_to_free_buffers(page)) |
2478 | J_ASSERT(!page_has_buffers(page)); | |
2479 | } | |
53e87268 | 2480 | return 0; |
470decc6 DK |
2481 | } |
2482 | ||
2483 | /* | |
2484 | * File a buffer on the given transaction list. | |
2485 | */ | |
f7f4bccb | 2486 | void __jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2487 | transaction_t *transaction, int jlist) |
2488 | { | |
2489 | struct journal_head **list = NULL; | |
2490 | int was_dirty = 0; | |
2491 | struct buffer_head *bh = jh2bh(jh); | |
2492 | ||
46417064 | 2493 | lockdep_assert_held(&jh->b_state_lock); |
470decc6 DK |
2494 | assert_spin_locked(&transaction->t_journal->j_list_lock); |
2495 | ||
2496 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
2497 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
4019191b | 2498 | jh->b_transaction == NULL); |
470decc6 DK |
2499 | |
2500 | if (jh->b_transaction && jh->b_jlist == jlist) | |
2501 | return; | |
2502 | ||
470decc6 DK |
2503 | if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
2504 | jlist == BJ_Shadow || jlist == BJ_Forget) { | |
f91d1d04 JK |
2505 | /* |
2506 | * For metadata buffers, we track dirty bit in buffer_jbddirty | |
2507 | * instead of buffer_dirty. We should not see a dirty bit set | |
2508 | * here because we clear it in do_get_write_access but e.g. | |
2509 | * tune2fs can modify the sb and set the dirty bit at any time | |
2510 | * so we try to gracefully handle that. | |
2511 | */ | |
2512 | if (buffer_dirty(bh)) | |
2513 | warn_dirty_buffer(bh); | |
470decc6 DK |
2514 | if (test_clear_buffer_dirty(bh) || |
2515 | test_clear_buffer_jbddirty(bh)) | |
2516 | was_dirty = 1; | |
2517 | } | |
2518 | ||
2519 | if (jh->b_transaction) | |
f7f4bccb | 2520 | __jbd2_journal_temp_unlink_buffer(jh); |
de1b7941 JK |
2521 | else |
2522 | jbd2_journal_grab_journal_head(bh); | |
470decc6 DK |
2523 | jh->b_transaction = transaction; |
2524 | ||
2525 | switch (jlist) { | |
2526 | case BJ_None: | |
2527 | J_ASSERT_JH(jh, !jh->b_committed_data); | |
2528 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
2529 | return; | |
470decc6 DK |
2530 | case BJ_Metadata: |
2531 | transaction->t_nr_buffers++; | |
2532 | list = &transaction->t_buffers; | |
2533 | break; | |
2534 | case BJ_Forget: | |
2535 | list = &transaction->t_forget; | |
2536 | break; | |
470decc6 DK |
2537 | case BJ_Shadow: |
2538 | list = &transaction->t_shadow_list; | |
2539 | break; | |
470decc6 DK |
2540 | case BJ_Reserved: |
2541 | list = &transaction->t_reserved_list; | |
2542 | break; | |
470decc6 DK |
2543 | } |
2544 | ||
2545 | __blist_add_buffer(list, jh); | |
2546 | jh->b_jlist = jlist; | |
2547 | ||
2548 | if (was_dirty) | |
2549 | set_buffer_jbddirty(bh); | |
2550 | } | |
2551 | ||
f7f4bccb | 2552 | void jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2553 | transaction_t *transaction, int jlist) |
2554 | { | |
46417064 | 2555 | spin_lock(&jh->b_state_lock); |
470decc6 | 2556 | spin_lock(&transaction->t_journal->j_list_lock); |
f7f4bccb | 2557 | __jbd2_journal_file_buffer(jh, transaction, jlist); |
470decc6 | 2558 | spin_unlock(&transaction->t_journal->j_list_lock); |
46417064 | 2559 | spin_unlock(&jh->b_state_lock); |
470decc6 DK |
2560 | } |
2561 | ||
2562 | /* | |
2563 | * Remove a buffer from its current buffer list in preparation for | |
2564 | * dropping it from its current transaction entirely. If the buffer has | |
2565 | * already started to be used by a subsequent transaction, refile the | |
2566 | * buffer on that transaction's metadata list. | |
2567 | * | |
de1b7941 | 2568 | * Called under j_list_lock |
46417064 | 2569 | * Called under jh->b_state_lock |
de1b7941 | 2570 | * |
93108ebb JK |
2571 | * When this function returns true, there's no next transaction to refile to |
2572 | * and the caller has to drop jh reference through | |
2573 | * jbd2_journal_put_journal_head(). | |
470decc6 | 2574 | */ |
93108ebb | 2575 | bool __jbd2_journal_refile_buffer(struct journal_head *jh) |
470decc6 | 2576 | { |
ba869023 | 2577 | int was_dirty, jlist; |
470decc6 DK |
2578 | struct buffer_head *bh = jh2bh(jh); |
2579 | ||
46417064 | 2580 | lockdep_assert_held(&jh->b_state_lock); |
470decc6 DK |
2581 | if (jh->b_transaction) |
2582 | assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); | |
2583 | ||
2584 | /* If the buffer is now unused, just drop it. */ | |
2585 | if (jh->b_next_transaction == NULL) { | |
f7f4bccb | 2586 | __jbd2_journal_unfile_buffer(jh); |
93108ebb | 2587 | return true; |
470decc6 DK |
2588 | } |
2589 | ||
2590 | /* | |
2591 | * It has been modified by a later transaction: add it to the new | |
2592 | * transaction's metadata list. | |
2593 | */ | |
2594 | ||
2595 | was_dirty = test_clear_buffer_jbddirty(bh); | |
f7f4bccb | 2596 | __jbd2_journal_temp_unlink_buffer(jh); |
24dc9864 LC |
2597 | |
2598 | /* | |
2599 | * b_transaction must be set, otherwise the new b_transaction won't | |
2600 | * be holding jh reference | |
2601 | */ | |
2602 | J_ASSERT_JH(jh, jh->b_transaction != NULL); | |
2603 | ||
de1b7941 JK |
2604 | /* |
2605 | * We set b_transaction here because b_next_transaction will inherit | |
2606 | * our jh reference and thus __jbd2_journal_file_buffer() must not | |
2607 | * take a new one. | |
2608 | */ | |
6c5d9112 QC |
2609 | WRITE_ONCE(jh->b_transaction, jh->b_next_transaction); |
2610 | WRITE_ONCE(jh->b_next_transaction, NULL); | |
ba869023 | 2611 | if (buffer_freed(bh)) |
2612 | jlist = BJ_Forget; | |
2613 | else if (jh->b_modified) | |
2614 | jlist = BJ_Metadata; | |
2615 | else | |
2616 | jlist = BJ_Reserved; | |
2617 | __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist); | |
470decc6 DK |
2618 | J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
2619 | ||
2620 | if (was_dirty) | |
2621 | set_buffer_jbddirty(bh); | |
93108ebb | 2622 | return false; |
470decc6 DK |
2623 | } |
2624 | ||
2625 | /* | |
de1b7941 JK |
2626 | * __jbd2_journal_refile_buffer() with necessary locking added. We take our |
2627 | * bh reference so that we can safely unlock bh. | |
2628 | * | |
2629 | * The jh and bh may be freed by this call. | |
470decc6 | 2630 | */ |
f7f4bccb | 2631 | void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 | 2632 | { |
93108ebb | 2633 | bool drop; |
470decc6 | 2634 | |
46417064 | 2635 | spin_lock(&jh->b_state_lock); |
470decc6 | 2636 | spin_lock(&journal->j_list_lock); |
93108ebb | 2637 | drop = __jbd2_journal_refile_buffer(jh); |
46417064 | 2638 | spin_unlock(&jh->b_state_lock); |
470decc6 | 2639 | spin_unlock(&journal->j_list_lock); |
93108ebb JK |
2640 | if (drop) |
2641 | jbd2_journal_put_journal_head(jh); | |
470decc6 | 2642 | } |
c851ed54 JK |
2643 | |
2644 | /* | |
2645 | * File inode in the inode list of the handle's transaction | |
2646 | */ | |
41617e1a | 2647 | static int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode, |
6ba0e7dc | 2648 | unsigned long flags, loff_t start_byte, loff_t end_byte) |
c851ed54 JK |
2649 | { |
2650 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 2651 | journal_t *journal; |
c851ed54 JK |
2652 | |
2653 | if (is_handle_aborted(handle)) | |
41a5b913 TT |
2654 | return -EROFS; |
2655 | journal = transaction->t_journal; | |
c851ed54 JK |
2656 | |
2657 | jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, | |
2658 | transaction->t_tid); | |
2659 | ||
c851ed54 | 2660 | spin_lock(&journal->j_list_lock); |
41617e1a | 2661 | jinode->i_flags |= flags; |
6ba0e7dc RZ |
2662 | |
2663 | if (jinode->i_dirty_end) { | |
2664 | jinode->i_dirty_start = min(jinode->i_dirty_start, start_byte); | |
2665 | jinode->i_dirty_end = max(jinode->i_dirty_end, end_byte); | |
2666 | } else { | |
2667 | jinode->i_dirty_start = start_byte; | |
2668 | jinode->i_dirty_end = end_byte; | |
2669 | } | |
2670 | ||
41617e1a | 2671 | /* Is inode already attached where we need it? */ |
c851ed54 JK |
2672 | if (jinode->i_transaction == transaction || |
2673 | jinode->i_next_transaction == transaction) | |
2674 | goto done; | |
2675 | ||
81be12c8 JK |
2676 | /* |
2677 | * We only ever set this variable to 1 so the test is safe. Since | |
2678 | * t_need_data_flush is likely to be set, we do the test to save some | |
2679 | * cacheline bouncing | |
2680 | */ | |
2681 | if (!transaction->t_need_data_flush) | |
2682 | transaction->t_need_data_flush = 1; | |
c851ed54 JK |
2683 | /* On some different transaction's list - should be |
2684 | * the committing one */ | |
2685 | if (jinode->i_transaction) { | |
2686 | J_ASSERT(jinode->i_next_transaction == NULL); | |
2687 | J_ASSERT(jinode->i_transaction == | |
2688 | journal->j_committing_transaction); | |
2689 | jinode->i_next_transaction = transaction; | |
2690 | goto done; | |
2691 | } | |
2692 | /* Not on any transaction list... */ | |
2693 | J_ASSERT(!jinode->i_next_transaction); | |
2694 | jinode->i_transaction = transaction; | |
2695 | list_add(&jinode->i_list, &transaction->t_inode_list); | |
2696 | done: | |
2697 | spin_unlock(&journal->j_list_lock); | |
2698 | ||
2699 | return 0; | |
2700 | } | |
2701 | ||
6ba0e7dc RZ |
2702 | int jbd2_journal_inode_ranged_write(handle_t *handle, |
2703 | struct jbd2_inode *jinode, loff_t start_byte, loff_t length) | |
2704 | { | |
2705 | return jbd2_journal_file_inode(handle, jinode, | |
2706 | JI_WRITE_DATA | JI_WAIT_DATA, start_byte, | |
2707 | start_byte + length - 1); | |
2708 | } | |
2709 | ||
2710 | int jbd2_journal_inode_ranged_wait(handle_t *handle, struct jbd2_inode *jinode, | |
2711 | loff_t start_byte, loff_t length) | |
2712 | { | |
2713 | return jbd2_journal_file_inode(handle, jinode, JI_WAIT_DATA, | |
2714 | start_byte, start_byte + length - 1); | |
41617e1a JK |
2715 | } |
2716 | ||
c851ed54 | 2717 | /* |
7f5aa215 JK |
2718 | * File truncate and transaction commit interact with each other in a |
2719 | * non-trivial way. If a transaction writing data block A is | |
2720 | * committing, we cannot discard the data by truncate until we have | |
2721 | * written them. Otherwise if we crashed after the transaction with | |
2722 | * write has committed but before the transaction with truncate has | |
2723 | * committed, we could see stale data in block A. This function is a | |
2724 | * helper to solve this problem. It starts writeout of the truncated | |
2725 | * part in case it is in the committing transaction. | |
2726 | * | |
2727 | * Filesystem code must call this function when inode is journaled in | |
2728 | * ordered mode before truncation happens and after the inode has been | |
2729 | * placed on orphan list with the new inode size. The second condition | |
2730 | * avoids the race that someone writes new data and we start | |
2731 | * committing the transaction after this function has been called but | |
2732 | * before a transaction for truncate is started (and furthermore it | |
2733 | * allows us to optimize the case where the addition to orphan list | |
2734 | * happens in the same transaction as write --- we don't have to write | |
2735 | * any data in such case). | |
c851ed54 | 2736 | */ |
7f5aa215 JK |
2737 | int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
2738 | struct jbd2_inode *jinode, | |
c851ed54 JK |
2739 | loff_t new_size) |
2740 | { | |
7f5aa215 | 2741 | transaction_t *inode_trans, *commit_trans; |
c851ed54 JK |
2742 | int ret = 0; |
2743 | ||
7f5aa215 JK |
2744 | /* This is a quick check to avoid locking if not necessary */ |
2745 | if (!jinode->i_transaction) | |
c851ed54 | 2746 | goto out; |
7f5aa215 JK |
2747 | /* Locks are here just to force reading of recent values, it is |
2748 | * enough that the transaction was not committing before we started | |
2749 | * a transaction adding the inode to orphan list */ | |
a931da6a | 2750 | read_lock(&journal->j_state_lock); |
c851ed54 | 2751 | commit_trans = journal->j_committing_transaction; |
a931da6a | 2752 | read_unlock(&journal->j_state_lock); |
7f5aa215 JK |
2753 | spin_lock(&journal->j_list_lock); |
2754 | inode_trans = jinode->i_transaction; | |
2755 | spin_unlock(&journal->j_list_lock); | |
2756 | if (inode_trans == commit_trans) { | |
2757 | ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, | |
c851ed54 JK |
2758 | new_size, LLONG_MAX); |
2759 | if (ret) | |
2760 | jbd2_journal_abort(journal, ret); | |
2761 | } | |
2762 | out: | |
2763 | return ret; | |
2764 | } |