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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 | ||
470decc6 | 65 | /* |
f7f4bccb | 66 | * jbd2_get_transaction: obtain a new transaction_t object. |
470decc6 | 67 | * |
0df6f469 | 68 | * Simply initialise a new transaction. Initialize it in |
470decc6 DK |
69 | * RUNNING state and add it to the current journal (which should not |
70 | * have an existing running transaction: we only make a new transaction | |
71 | * once we have started to commit the old one). | |
72 | * | |
73 | * Preconditions: | |
74 | * The journal MUST be locked. We don't perform atomic mallocs on the | |
75 | * new transaction and we can't block without protecting against other | |
76 | * processes trying to touch the journal while it is in transition. | |
77 | * | |
470decc6 DK |
78 | */ |
79 | ||
0df6f469 LS |
80 | static void jbd2_get_transaction(journal_t *journal, |
81 | transaction_t *transaction) | |
470decc6 DK |
82 | { |
83 | transaction->t_journal = journal; | |
84 | transaction->t_state = T_RUNNING; | |
e07f7183 | 85 | transaction->t_start_time = ktime_get(); |
470decc6 DK |
86 | transaction->t_tid = journal->j_transaction_sequence++; |
87 | transaction->t_expires = jiffies + journal->j_commit_interval; | |
88 | spin_lock_init(&transaction->t_handle_lock); | |
a51dca9c | 89 | atomic_set(&transaction->t_updates, 0); |
8f7d89f3 JK |
90 | atomic_set(&transaction->t_outstanding_credits, |
91 | atomic_read(&journal->j_reserved_credits)); | |
8dd42046 | 92 | atomic_set(&transaction->t_handle_count, 0); |
c851ed54 | 93 | INIT_LIST_HEAD(&transaction->t_inode_list); |
3e624fc7 | 94 | INIT_LIST_HEAD(&transaction->t_private_list); |
470decc6 DK |
95 | |
96 | /* Set up the commit timer for the new transaction. */ | |
b1f485f2 | 97 | journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires); |
470decc6 DK |
98 | add_timer(&journal->j_commit_timer); |
99 | ||
100 | J_ASSERT(journal->j_running_transaction == NULL); | |
101 | journal->j_running_transaction = transaction; | |
8e85fb3f JL |
102 | transaction->t_max_wait = 0; |
103 | transaction->t_start = jiffies; | |
9fff24aa | 104 | transaction->t_requested = 0; |
470decc6 DK |
105 | } |
106 | ||
107 | /* | |
108 | * Handle management. | |
109 | * | |
110 | * A handle_t is an object which represents a single atomic update to a | |
111 | * filesystem, and which tracks all of the modifications which form part | |
112 | * of that one update. | |
113 | */ | |
114 | ||
6d0bf005 | 115 | /* |
28e35e42 | 116 | * Update transaction's maximum wait time, if debugging is enabled. |
6d0bf005 TT |
117 | * |
118 | * In order for t_max_wait to be reliable, it must be protected by a | |
119 | * lock. But doing so will mean that start_this_handle() can not be | |
120 | * run in parallel on SMP systems, which limits our scalability. So | |
121 | * unless debugging is enabled, we no longer update t_max_wait, which | |
122 | * means that maximum wait time reported by the jbd2_run_stats | |
123 | * tracepoint will always be zero. | |
124 | */ | |
28e35e42 TM |
125 | static inline void update_t_max_wait(transaction_t *transaction, |
126 | unsigned long ts) | |
6d0bf005 TT |
127 | { |
128 | #ifdef CONFIG_JBD2_DEBUG | |
6d0bf005 TT |
129 | if (jbd2_journal_enable_debug && |
130 | time_after(transaction->t_start, ts)) { | |
131 | ts = jbd2_time_diff(ts, transaction->t_start); | |
132 | spin_lock(&transaction->t_handle_lock); | |
133 | if (ts > transaction->t_max_wait) | |
134 | transaction->t_max_wait = ts; | |
135 | spin_unlock(&transaction->t_handle_lock); | |
136 | } | |
137 | #endif | |
138 | } | |
139 | ||
8f7d89f3 | 140 | /* |
96f1e097 JK |
141 | * Wait until running transaction passes to T_FLUSH state and new transaction |
142 | * can thus be started. Also starts the commit if needed. The function expects | |
143 | * running transaction to exist and releases j_state_lock. | |
8f7d89f3 JK |
144 | */ |
145 | static void wait_transaction_locked(journal_t *journal) | |
146 | __releases(journal->j_state_lock) | |
147 | { | |
148 | DEFINE_WAIT(wait); | |
149 | int need_to_start; | |
150 | tid_t tid = journal->j_running_transaction->t_tid; | |
151 | ||
152 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, | |
153 | TASK_UNINTERRUPTIBLE); | |
154 | need_to_start = !tid_geq(journal->j_commit_request, tid); | |
155 | read_unlock(&journal->j_state_lock); | |
156 | if (need_to_start) | |
157 | jbd2_log_start_commit(journal, tid); | |
e03a9976 | 158 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 JK |
159 | schedule(); |
160 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
161 | } | |
162 | ||
96f1e097 JK |
163 | /* |
164 | * Wait until running transaction transitions from T_SWITCH to T_FLUSH | |
165 | * state and new transaction can thus be started. The function releases | |
166 | * j_state_lock. | |
167 | */ | |
168 | static void wait_transaction_switching(journal_t *journal) | |
169 | __releases(journal->j_state_lock) | |
170 | { | |
171 | DEFINE_WAIT(wait); | |
172 | ||
173 | if (WARN_ON(!journal->j_running_transaction || | |
174 | journal->j_running_transaction->t_state != T_SWITCH)) | |
175 | return; | |
176 | prepare_to_wait(&journal->j_wait_transaction_locked, &wait, | |
177 | TASK_UNINTERRUPTIBLE); | |
178 | read_unlock(&journal->j_state_lock); | |
179 | /* | |
180 | * We don't call jbd2_might_wait_for_commit() here as there's no | |
181 | * waiting for outstanding handles happening anymore in T_SWITCH state | |
182 | * and handling of reserved handles actually relies on that for | |
183 | * correctness. | |
184 | */ | |
185 | schedule(); | |
186 | finish_wait(&journal->j_wait_transaction_locked, &wait); | |
187 | } | |
188 | ||
8f7d89f3 JK |
189 | static void sub_reserved_credits(journal_t *journal, int blocks) |
190 | { | |
191 | atomic_sub(blocks, &journal->j_reserved_credits); | |
192 | wake_up(&journal->j_wait_reserved); | |
193 | } | |
194 | ||
195 | /* | |
196 | * Wait until we can add credits for handle to the running transaction. Called | |
197 | * with j_state_lock held for reading. Returns 0 if handle joined the running | |
198 | * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and | |
199 | * caller must retry. | |
200 | */ | |
201 | static int add_transaction_credits(journal_t *journal, int blocks, | |
202 | int rsv_blocks) | |
203 | { | |
204 | transaction_t *t = journal->j_running_transaction; | |
205 | int needed; | |
206 | int total = blocks + rsv_blocks; | |
207 | ||
208 | /* | |
209 | * If the current transaction is locked down for commit, wait | |
210 | * for the lock to be released. | |
211 | */ | |
96f1e097 JK |
212 | if (t->t_state != T_RUNNING) { |
213 | WARN_ON_ONCE(t->t_state >= T_FLUSH); | |
8f7d89f3 JK |
214 | wait_transaction_locked(journal); |
215 | return 1; | |
216 | } | |
217 | ||
218 | /* | |
219 | * If there is not enough space left in the log to write all | |
220 | * potential buffers requested by this operation, we need to | |
221 | * stall pending a log checkpoint to free some more log space. | |
222 | */ | |
223 | needed = atomic_add_return(total, &t->t_outstanding_credits); | |
224 | if (needed > journal->j_max_transaction_buffers) { | |
225 | /* | |
226 | * If the current transaction is already too large, | |
227 | * then start to commit it: we can then go back and | |
228 | * attach this handle to a new transaction. | |
229 | */ | |
230 | atomic_sub(total, &t->t_outstanding_credits); | |
6d3ec14d LC |
231 | |
232 | /* | |
233 | * Is the number of reserved credits in the current transaction too | |
234 | * big to fit this handle? Wait until reserved credits are freed. | |
235 | */ | |
236 | if (atomic_read(&journal->j_reserved_credits) + total > | |
237 | journal->j_max_transaction_buffers) { | |
238 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 239 | jbd2_might_wait_for_commit(journal); |
6d3ec14d LC |
240 | wait_event(journal->j_wait_reserved, |
241 | atomic_read(&journal->j_reserved_credits) + total <= | |
242 | journal->j_max_transaction_buffers); | |
243 | return 1; | |
244 | } | |
245 | ||
8f7d89f3 JK |
246 | wait_transaction_locked(journal); |
247 | return 1; | |
248 | } | |
249 | ||
250 | /* | |
251 | * The commit code assumes that it can get enough log space | |
252 | * without forcing a checkpoint. This is *critical* for | |
253 | * correctness: a checkpoint of a buffer which is also | |
254 | * associated with a committing transaction creates a deadlock, | |
255 | * so commit simply cannot force through checkpoints. | |
256 | * | |
257 | * We must therefore ensure the necessary space in the journal | |
258 | * *before* starting to dirty potentially checkpointed buffers | |
259 | * in the new transaction. | |
260 | */ | |
261 | if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) { | |
262 | atomic_sub(total, &t->t_outstanding_credits); | |
263 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 264 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 JK |
265 | write_lock(&journal->j_state_lock); |
266 | if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) | |
267 | __jbd2_log_wait_for_space(journal); | |
268 | write_unlock(&journal->j_state_lock); | |
269 | return 1; | |
270 | } | |
271 | ||
272 | /* No reservation? We are done... */ | |
273 | if (!rsv_blocks) | |
274 | return 0; | |
275 | ||
276 | needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits); | |
277 | /* We allow at most half of a transaction to be reserved */ | |
278 | if (needed > journal->j_max_transaction_buffers / 2) { | |
279 | sub_reserved_credits(journal, rsv_blocks); | |
280 | atomic_sub(total, &t->t_outstanding_credits); | |
281 | read_unlock(&journal->j_state_lock); | |
e03a9976 | 282 | jbd2_might_wait_for_commit(journal); |
8f7d89f3 JK |
283 | wait_event(journal->j_wait_reserved, |
284 | atomic_read(&journal->j_reserved_credits) + rsv_blocks | |
285 | <= journal->j_max_transaction_buffers / 2); | |
286 | return 1; | |
287 | } | |
288 | return 0; | |
289 | } | |
290 | ||
470decc6 DK |
291 | /* |
292 | * start_this_handle: Given a handle, deal with any locking or stalling | |
293 | * needed to make sure that there is enough journal space for the handle | |
294 | * to begin. Attach the handle to a transaction and set up the | |
295 | * transaction's buffer credits. | |
296 | */ | |
297 | ||
47def826 | 298 | static int start_this_handle(journal_t *journal, handle_t *handle, |
d2159fb7 | 299 | gfp_t gfp_mask) |
470decc6 | 300 | { |
e4471831 | 301 | transaction_t *transaction, *new_transaction = NULL; |
8f7d89f3 JK |
302 | int blocks = handle->h_buffer_credits; |
303 | int rsv_blocks = 0; | |
28e35e42 | 304 | unsigned long ts = jiffies; |
470decc6 | 305 | |
6d3ec14d LC |
306 | if (handle->h_rsv_handle) |
307 | rsv_blocks = handle->h_rsv_handle->h_buffer_credits; | |
308 | ||
8f7d89f3 | 309 | /* |
6d3ec14d LC |
310 | * Limit the number of reserved credits to 1/2 of maximum transaction |
311 | * size and limit the number of total credits to not exceed maximum | |
312 | * transaction size per operation. | |
8f7d89f3 | 313 | */ |
6d3ec14d LC |
314 | if ((rsv_blocks > journal->j_max_transaction_buffers / 2) || |
315 | (rsv_blocks + blocks > journal->j_max_transaction_buffers)) { | |
316 | printk(KERN_ERR "JBD2: %s wants too many credits " | |
317 | "credits:%d rsv_credits:%d max:%d\n", | |
318 | current->comm, blocks, rsv_blocks, | |
319 | journal->j_max_transaction_buffers); | |
320 | WARN_ON(1); | |
47def826 | 321 | return -ENOSPC; |
470decc6 DK |
322 | } |
323 | ||
324 | alloc_transaction: | |
325 | if (!journal->j_running_transaction) { | |
6ccaf3e2 MH |
326 | /* |
327 | * If __GFP_FS is not present, then we may be being called from | |
328 | * inside the fs writeback layer, so we MUST NOT fail. | |
329 | */ | |
330 | if ((gfp_mask & __GFP_FS) == 0) | |
331 | gfp_mask |= __GFP_NOFAIL; | |
b2f4edb3 WG |
332 | new_transaction = kmem_cache_zalloc(transaction_cache, |
333 | gfp_mask); | |
6ccaf3e2 | 334 | if (!new_transaction) |
47def826 | 335 | return -ENOMEM; |
470decc6 DK |
336 | } |
337 | ||
338 | jbd_debug(3, "New handle %p going live.\n", handle); | |
339 | ||
470decc6 DK |
340 | /* |
341 | * We need to hold j_state_lock until t_updates has been incremented, | |
342 | * for proper journal barrier handling | |
343 | */ | |
a931da6a TT |
344 | repeat: |
345 | read_lock(&journal->j_state_lock); | |
5c2178e7 | 346 | BUG_ON(journal->j_flags & JBD2_UNMOUNT); |
470decc6 | 347 | if (is_journal_aborted(journal) || |
f7f4bccb | 348 | (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
a931da6a | 349 | read_unlock(&journal->j_state_lock); |
0c2022ec | 350 | jbd2_journal_free_transaction(new_transaction); |
47def826 | 351 | return -EROFS; |
470decc6 DK |
352 | } |
353 | ||
8f7d89f3 JK |
354 | /* |
355 | * Wait on the journal's transaction barrier if necessary. Specifically | |
356 | * we allow reserved handles to proceed because otherwise commit could | |
357 | * deadlock on page writeback not being able to complete. | |
358 | */ | |
359 | if (!handle->h_reserved && journal->j_barrier_count) { | |
a931da6a | 360 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
361 | wait_event(journal->j_wait_transaction_locked, |
362 | journal->j_barrier_count == 0); | |
363 | goto repeat; | |
364 | } | |
365 | ||
366 | if (!journal->j_running_transaction) { | |
a931da6a TT |
367 | read_unlock(&journal->j_state_lock); |
368 | if (!new_transaction) | |
470decc6 | 369 | goto alloc_transaction; |
a931da6a | 370 | write_lock(&journal->j_state_lock); |
d7961c7f | 371 | if (!journal->j_running_transaction && |
8f7d89f3 | 372 | (handle->h_reserved || !journal->j_barrier_count)) { |
a931da6a TT |
373 | jbd2_get_transaction(journal, new_transaction); |
374 | new_transaction = NULL; | |
470decc6 | 375 | } |
a931da6a TT |
376 | write_unlock(&journal->j_state_lock); |
377 | goto repeat; | |
470decc6 DK |
378 | } |
379 | ||
380 | transaction = journal->j_running_transaction; | |
381 | ||
8f7d89f3 JK |
382 | if (!handle->h_reserved) { |
383 | /* We may have dropped j_state_lock - restart in that case */ | |
384 | if (add_transaction_credits(journal, blocks, rsv_blocks)) | |
385 | goto repeat; | |
386 | } else { | |
470decc6 | 387 | /* |
8f7d89f3 JK |
388 | * We have handle reserved so we are allowed to join T_LOCKED |
389 | * transaction and we don't have to check for transaction size | |
96f1e097 JK |
390 | * and journal space. But we still have to wait while running |
391 | * transaction is being switched to a committing one as it | |
392 | * won't wait for any handles anymore. | |
470decc6 | 393 | */ |
96f1e097 JK |
394 | if (transaction->t_state == T_SWITCH) { |
395 | wait_transaction_switching(journal); | |
396 | goto repeat; | |
397 | } | |
8f7d89f3 JK |
398 | sub_reserved_credits(journal, blocks); |
399 | handle->h_reserved = 0; | |
470decc6 DK |
400 | } |
401 | ||
402 | /* OK, account for the buffers that this operation expects to | |
8dd42046 | 403 | * use and add the handle to the running transaction. |
8dd42046 | 404 | */ |
28e35e42 | 405 | update_t_max_wait(transaction, ts); |
470decc6 | 406 | handle->h_transaction = transaction; |
8f7d89f3 | 407 | handle->h_requested_credits = blocks; |
343d9c28 | 408 | handle->h_start_jiffies = jiffies; |
a51dca9c | 409 | atomic_inc(&transaction->t_updates); |
8dd42046 | 410 | atomic_inc(&transaction->t_handle_count); |
8f7d89f3 JK |
411 | jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n", |
412 | handle, blocks, | |
a51dca9c | 413 | atomic_read(&transaction->t_outstanding_credits), |
76c39904 | 414 | jbd2_log_space_left(journal)); |
a931da6a | 415 | read_unlock(&journal->j_state_lock); |
41a5b913 | 416 | current->journal_info = handle; |
9599b0e5 | 417 | |
ab714aff | 418 | rwsem_acquire_read(&journal->j_trans_commit_map, 0, 0, _THIS_IP_); |
0c2022ec | 419 | jbd2_journal_free_transaction(new_transaction); |
81378da6 MH |
420 | /* |
421 | * Ensure that no allocations done while the transaction is open are | |
422 | * going to recurse back to the fs layer. | |
423 | */ | |
424 | handle->saved_alloc_context = memalloc_nofs_save(); | |
47def826 | 425 | return 0; |
470decc6 DK |
426 | } |
427 | ||
428 | /* Allocate a new handle. This should probably be in a slab... */ | |
429 | static handle_t *new_handle(int nblocks) | |
430 | { | |
af1e76d6 | 431 | handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
470decc6 DK |
432 | if (!handle) |
433 | return NULL; | |
470decc6 DK |
434 | handle->h_buffer_credits = nblocks; |
435 | handle->h_ref = 1; | |
436 | ||
437 | return handle; | |
438 | } | |
439 | ||
8f7d89f3 JK |
440 | handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks, |
441 | gfp_t gfp_mask, unsigned int type, | |
442 | unsigned int line_no) | |
470decc6 DK |
443 | { |
444 | handle_t *handle = journal_current_handle(); | |
445 | int err; | |
446 | ||
447 | if (!journal) | |
448 | return ERR_PTR(-EROFS); | |
449 | ||
450 | if (handle) { | |
451 | J_ASSERT(handle->h_transaction->t_journal == journal); | |
452 | handle->h_ref++; | |
453 | return handle; | |
454 | } | |
455 | ||
456 | handle = new_handle(nblocks); | |
457 | if (!handle) | |
458 | return ERR_PTR(-ENOMEM); | |
8f7d89f3 JK |
459 | if (rsv_blocks) { |
460 | handle_t *rsv_handle; | |
461 | ||
462 | rsv_handle = new_handle(rsv_blocks); | |
463 | if (!rsv_handle) { | |
464 | jbd2_free_handle(handle); | |
465 | return ERR_PTR(-ENOMEM); | |
466 | } | |
467 | rsv_handle->h_reserved = 1; | |
468 | rsv_handle->h_journal = journal; | |
469 | handle->h_rsv_handle = rsv_handle; | |
470 | } | |
470decc6 | 471 | |
47def826 | 472 | err = start_this_handle(journal, handle, gfp_mask); |
470decc6 | 473 | if (err < 0) { |
8f7d89f3 JK |
474 | if (handle->h_rsv_handle) |
475 | jbd2_free_handle(handle->h_rsv_handle); | |
af1e76d6 | 476 | jbd2_free_handle(handle); |
df05c1b8 | 477 | return ERR_PTR(err); |
470decc6 | 478 | } |
343d9c28 TT |
479 | handle->h_type = type; |
480 | handle->h_line_no = line_no; | |
481 | trace_jbd2_handle_start(journal->j_fs_dev->bd_dev, | |
482 | handle->h_transaction->t_tid, type, | |
483 | line_no, nblocks); | |
81378da6 | 484 | |
470decc6 DK |
485 | return handle; |
486 | } | |
47def826 TT |
487 | EXPORT_SYMBOL(jbd2__journal_start); |
488 | ||
489 | ||
91e4775d MCC |
490 | /** |
491 | * handle_t *jbd2_journal_start() - Obtain a new handle. | |
492 | * @journal: Journal to start transaction on. | |
493 | * @nblocks: number of block buffer we might modify | |
494 | * | |
495 | * We make sure that the transaction can guarantee at least nblocks of | |
496 | * modified buffers in the log. We block until the log can guarantee | |
497 | * that much space. Additionally, if rsv_blocks > 0, we also create another | |
498 | * handle with rsv_blocks reserved blocks in the journal. This handle is | |
499 | * is stored in h_rsv_handle. It is not attached to any particular transaction | |
500 | * and thus doesn't block transaction commit. If the caller uses this reserved | |
501 | * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop() | |
502 | * on the parent handle will dispose the reserved one. Reserved handle has to | |
503 | * be converted to a normal handle using jbd2_journal_start_reserved() before | |
504 | * it can be used. | |
505 | * | |
506 | * Return a pointer to a newly allocated handle, or an ERR_PTR() value | |
507 | * on failure. | |
508 | */ | |
47def826 TT |
509 | handle_t *jbd2_journal_start(journal_t *journal, int nblocks) |
510 | { | |
8f7d89f3 | 511 | return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0); |
47def826 TT |
512 | } |
513 | EXPORT_SYMBOL(jbd2_journal_start); | |
514 | ||
8f7d89f3 JK |
515 | void jbd2_journal_free_reserved(handle_t *handle) |
516 | { | |
517 | journal_t *journal = handle->h_journal; | |
518 | ||
519 | WARN_ON(!handle->h_reserved); | |
520 | sub_reserved_credits(journal, handle->h_buffer_credits); | |
521 | jbd2_free_handle(handle); | |
522 | } | |
523 | EXPORT_SYMBOL(jbd2_journal_free_reserved); | |
524 | ||
525 | /** | |
f69120ce | 526 | * int jbd2_journal_start_reserved() - start reserved handle |
8f7d89f3 | 527 | * @handle: handle to start |
f69120ce TH |
528 | * @type: for handle statistics |
529 | * @line_no: for handle statistics | |
8f7d89f3 JK |
530 | * |
531 | * Start handle that has been previously reserved with jbd2_journal_reserve(). | |
532 | * This attaches @handle to the running transaction (or creates one if there's | |
533 | * not transaction running). Unlike jbd2_journal_start() this function cannot | |
534 | * block on journal commit, checkpointing, or similar stuff. It can block on | |
535 | * memory allocation or frozen journal though. | |
536 | * | |
537 | * Return 0 on success, non-zero on error - handle is freed in that case. | |
538 | */ | |
539 | int jbd2_journal_start_reserved(handle_t *handle, unsigned int type, | |
540 | unsigned int line_no) | |
541 | { | |
542 | journal_t *journal = handle->h_journal; | |
543 | int ret = -EIO; | |
544 | ||
545 | if (WARN_ON(!handle->h_reserved)) { | |
546 | /* Someone passed in normal handle? Just stop it. */ | |
547 | jbd2_journal_stop(handle); | |
548 | return ret; | |
549 | } | |
550 | /* | |
551 | * Usefulness of mixing of reserved and unreserved handles is | |
552 | * questionable. So far nobody seems to need it so just error out. | |
553 | */ | |
554 | if (WARN_ON(current->journal_info)) { | |
555 | jbd2_journal_free_reserved(handle); | |
556 | return ret; | |
557 | } | |
558 | ||
559 | handle->h_journal = NULL; | |
8f7d89f3 JK |
560 | /* |
561 | * GFP_NOFS is here because callers are likely from writeback or | |
562 | * similarly constrained call sites | |
563 | */ | |
564 | ret = start_this_handle(journal, handle, GFP_NOFS); | |
92e3b405 | 565 | if (ret < 0) { |
b2569260 | 566 | handle->h_journal = journal; |
8f7d89f3 | 567 | jbd2_journal_free_reserved(handle); |
92e3b405 DC |
568 | return ret; |
569 | } | |
8f7d89f3 JK |
570 | handle->h_type = type; |
571 | handle->h_line_no = line_no; | |
92e3b405 | 572 | return 0; |
8f7d89f3 JK |
573 | } |
574 | EXPORT_SYMBOL(jbd2_journal_start_reserved); | |
470decc6 DK |
575 | |
576 | /** | |
f7f4bccb | 577 | * int jbd2_journal_extend() - extend buffer credits. |
470decc6 DK |
578 | * @handle: handle to 'extend' |
579 | * @nblocks: nr blocks to try to extend by. | |
580 | * | |
581 | * Some transactions, such as large extends and truncates, can be done | |
582 | * atomically all at once or in several stages. The operation requests | |
bd7ced98 | 583 | * a credit for a number of buffer modifications in advance, but can |
470decc6 DK |
584 | * extend its credit if it needs more. |
585 | * | |
f7f4bccb | 586 | * jbd2_journal_extend tries to give the running handle more buffer credits. |
470decc6 DK |
587 | * It does not guarantee that allocation - this is a best-effort only. |
588 | * The calling process MUST be able to deal cleanly with a failure to | |
589 | * extend here. | |
590 | * | |
591 | * Return 0 on success, non-zero on failure. | |
592 | * | |
593 | * return code < 0 implies an error | |
594 | * return code > 0 implies normal transaction-full status. | |
595 | */ | |
f7f4bccb | 596 | int jbd2_journal_extend(handle_t *handle, int nblocks) |
470decc6 DK |
597 | { |
598 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 599 | journal_t *journal; |
470decc6 DK |
600 | int result; |
601 | int wanted; | |
602 | ||
470decc6 | 603 | if (is_handle_aborted(handle)) |
41a5b913 TT |
604 | return -EROFS; |
605 | journal = transaction->t_journal; | |
470decc6 DK |
606 | |
607 | result = 1; | |
608 | ||
a931da6a | 609 | read_lock(&journal->j_state_lock); |
470decc6 DK |
610 | |
611 | /* Don't extend a locked-down transaction! */ | |
41a5b913 | 612 | if (transaction->t_state != T_RUNNING) { |
470decc6 DK |
613 | jbd_debug(3, "denied handle %p %d blocks: " |
614 | "transaction not running\n", handle, nblocks); | |
615 | goto error_out; | |
616 | } | |
617 | ||
618 | spin_lock(&transaction->t_handle_lock); | |
fe1e8db5 JK |
619 | wanted = atomic_add_return(nblocks, |
620 | &transaction->t_outstanding_credits); | |
470decc6 DK |
621 | |
622 | if (wanted > journal->j_max_transaction_buffers) { | |
623 | jbd_debug(3, "denied handle %p %d blocks: " | |
624 | "transaction too large\n", handle, nblocks); | |
fe1e8db5 | 625 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
626 | goto unlock; |
627 | } | |
628 | ||
76c39904 JK |
629 | if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) > |
630 | jbd2_log_space_left(journal)) { | |
470decc6 DK |
631 | jbd_debug(3, "denied handle %p %d blocks: " |
632 | "insufficient log space\n", handle, nblocks); | |
fe1e8db5 | 633 | atomic_sub(nblocks, &transaction->t_outstanding_credits); |
470decc6 DK |
634 | goto unlock; |
635 | } | |
636 | ||
343d9c28 | 637 | trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev, |
41a5b913 | 638 | transaction->t_tid, |
343d9c28 TT |
639 | handle->h_type, handle->h_line_no, |
640 | handle->h_buffer_credits, | |
641 | nblocks); | |
642 | ||
470decc6 | 643 | handle->h_buffer_credits += nblocks; |
343d9c28 | 644 | handle->h_requested_credits += nblocks; |
470decc6 DK |
645 | result = 0; |
646 | ||
647 | jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); | |
648 | unlock: | |
649 | spin_unlock(&transaction->t_handle_lock); | |
650 | error_out: | |
a931da6a | 651 | read_unlock(&journal->j_state_lock); |
470decc6 DK |
652 | return result; |
653 | } | |
654 | ||
655 | ||
656 | /** | |
f7f4bccb | 657 | * int jbd2_journal_restart() - restart a handle . |
470decc6 DK |
658 | * @handle: handle to restart |
659 | * @nblocks: nr credits requested | |
f69120ce | 660 | * @gfp_mask: memory allocation flags (for start_this_handle) |
470decc6 DK |
661 | * |
662 | * Restart a handle for a multi-transaction filesystem | |
663 | * operation. | |
664 | * | |
f7f4bccb MC |
665 | * If the jbd2_journal_extend() call above fails to grant new buffer credits |
666 | * to a running handle, a call to jbd2_journal_restart will commit the | |
470decc6 | 667 | * handle's transaction so far and reattach the handle to a new |
bd7ced98 | 668 | * transaction capable of guaranteeing the requested number of |
8f7d89f3 JK |
669 | * credits. We preserve reserved handle if there's any attached to the |
670 | * passed in handle. | |
470decc6 | 671 | */ |
d2159fb7 | 672 | int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask) |
470decc6 DK |
673 | { |
674 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 675 | journal_t *journal; |
e4471831 TT |
676 | tid_t tid; |
677 | int need_to_start, ret; | |
470decc6 DK |
678 | |
679 | /* If we've had an abort of any type, don't even think about | |
680 | * actually doing the restart! */ | |
681 | if (is_handle_aborted(handle)) | |
682 | return 0; | |
41a5b913 | 683 | journal = transaction->t_journal; |
470decc6 DK |
684 | |
685 | /* | |
686 | * First unlink the handle from its current transaction, and start the | |
687 | * commit on that. | |
688 | */ | |
a51dca9c | 689 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 DK |
690 | J_ASSERT(journal_current_handle() == handle); |
691 | ||
a931da6a | 692 | read_lock(&journal->j_state_lock); |
470decc6 | 693 | spin_lock(&transaction->t_handle_lock); |
a51dca9c TT |
694 | atomic_sub(handle->h_buffer_credits, |
695 | &transaction->t_outstanding_credits); | |
8f7d89f3 JK |
696 | if (handle->h_rsv_handle) { |
697 | sub_reserved_credits(journal, | |
698 | handle->h_rsv_handle->h_buffer_credits); | |
699 | } | |
a51dca9c | 700 | if (atomic_dec_and_test(&transaction->t_updates)) |
470decc6 | 701 | wake_up(&journal->j_wait_updates); |
39c04153 | 702 | tid = transaction->t_tid; |
470decc6 | 703 | spin_unlock(&transaction->t_handle_lock); |
41a5b913 TT |
704 | handle->h_transaction = NULL; |
705 | current->journal_info = NULL; | |
470decc6 DK |
706 | |
707 | jbd_debug(2, "restarting handle %p\n", handle); | |
e4471831 | 708 | need_to_start = !tid_geq(journal->j_commit_request, tid); |
a931da6a | 709 | read_unlock(&journal->j_state_lock); |
e4471831 TT |
710 | if (need_to_start) |
711 | jbd2_log_start_commit(journal, tid); | |
470decc6 | 712 | |
ab714aff | 713 | rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_); |
470decc6 | 714 | handle->h_buffer_credits = nblocks; |
b4709067 TE |
715 | /* |
716 | * Restore the original nofs context because the journal restart | |
717 | * is basically the same thing as journal stop and start. | |
718 | * start_this_handle will start a new nofs context. | |
719 | */ | |
720 | memalloc_nofs_restore(handle->saved_alloc_context); | |
47def826 | 721 | ret = start_this_handle(journal, handle, gfp_mask); |
470decc6 DK |
722 | return ret; |
723 | } | |
47def826 | 724 | EXPORT_SYMBOL(jbd2__journal_restart); |
470decc6 DK |
725 | |
726 | ||
47def826 TT |
727 | int jbd2_journal_restart(handle_t *handle, int nblocks) |
728 | { | |
729 | return jbd2__journal_restart(handle, nblocks, GFP_NOFS); | |
730 | } | |
731 | EXPORT_SYMBOL(jbd2_journal_restart); | |
732 | ||
470decc6 | 733 | /** |
f7f4bccb | 734 | * void jbd2_journal_lock_updates () - establish a transaction barrier. |
470decc6 DK |
735 | * @journal: Journal to establish a barrier on. |
736 | * | |
737 | * This locks out any further updates from being started, and blocks | |
738 | * until all existing updates have completed, returning only once the | |
739 | * journal is in a quiescent state with no updates running. | |
740 | * | |
741 | * The journal lock should not be held on entry. | |
742 | */ | |
f7f4bccb | 743 | void jbd2_journal_lock_updates(journal_t *journal) |
470decc6 DK |
744 | { |
745 | DEFINE_WAIT(wait); | |
746 | ||
1eaa566d JK |
747 | jbd2_might_wait_for_commit(journal); |
748 | ||
a931da6a | 749 | write_lock(&journal->j_state_lock); |
470decc6 DK |
750 | ++journal->j_barrier_count; |
751 | ||
8f7d89f3 JK |
752 | /* Wait until there are no reserved handles */ |
753 | if (atomic_read(&journal->j_reserved_credits)) { | |
754 | write_unlock(&journal->j_state_lock); | |
755 | wait_event(journal->j_wait_reserved, | |
756 | atomic_read(&journal->j_reserved_credits) == 0); | |
757 | write_lock(&journal->j_state_lock); | |
758 | } | |
759 | ||
470decc6 DK |
760 | /* Wait until there are no running updates */ |
761 | while (1) { | |
762 | transaction_t *transaction = journal->j_running_transaction; | |
763 | ||
764 | if (!transaction) | |
765 | break; | |
766 | ||
767 | spin_lock(&transaction->t_handle_lock); | |
9837d8e9 JK |
768 | prepare_to_wait(&journal->j_wait_updates, &wait, |
769 | TASK_UNINTERRUPTIBLE); | |
a51dca9c | 770 | if (!atomic_read(&transaction->t_updates)) { |
470decc6 | 771 | spin_unlock(&transaction->t_handle_lock); |
9837d8e9 | 772 | finish_wait(&journal->j_wait_updates, &wait); |
470decc6 DK |
773 | break; |
774 | } | |
470decc6 | 775 | spin_unlock(&transaction->t_handle_lock); |
a931da6a | 776 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
777 | schedule(); |
778 | finish_wait(&journal->j_wait_updates, &wait); | |
a931da6a | 779 | write_lock(&journal->j_state_lock); |
470decc6 | 780 | } |
a931da6a | 781 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
782 | |
783 | /* | |
784 | * We have now established a barrier against other normal updates, but | |
f7f4bccb | 785 | * we also need to barrier against other jbd2_journal_lock_updates() calls |
470decc6 DK |
786 | * to make sure that we serialise special journal-locked operations |
787 | * too. | |
788 | */ | |
789 | mutex_lock(&journal->j_barrier); | |
790 | } | |
791 | ||
792 | /** | |
f7f4bccb | 793 | * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier |
470decc6 DK |
794 | * @journal: Journal to release the barrier on. |
795 | * | |
f7f4bccb | 796 | * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
470decc6 DK |
797 | * |
798 | * Should be called without the journal lock held. | |
799 | */ | |
f7f4bccb | 800 | void jbd2_journal_unlock_updates (journal_t *journal) |
470decc6 DK |
801 | { |
802 | J_ASSERT(journal->j_barrier_count != 0); | |
803 | ||
804 | mutex_unlock(&journal->j_barrier); | |
a931da6a | 805 | write_lock(&journal->j_state_lock); |
470decc6 | 806 | --journal->j_barrier_count; |
a931da6a | 807 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
808 | wake_up(&journal->j_wait_transaction_locked); |
809 | } | |
810 | ||
f91d1d04 | 811 | static void warn_dirty_buffer(struct buffer_head *bh) |
470decc6 | 812 | { |
f91d1d04 | 813 | printk(KERN_WARNING |
a1c6f057 | 814 | "JBD2: Spotted dirty metadata buffer (dev = %pg, blocknr = %llu). " |
f91d1d04 JK |
815 | "There's a risk of filesystem corruption in case of system " |
816 | "crash.\n", | |
a1c6f057 | 817 | bh->b_bdev, (unsigned long long)bh->b_blocknr); |
470decc6 DK |
818 | } |
819 | ||
ee57aba1 JK |
820 | /* Call t_frozen trigger and copy buffer data into jh->b_frozen_data. */ |
821 | static void jbd2_freeze_jh_data(struct journal_head *jh) | |
822 | { | |
823 | struct page *page; | |
824 | int offset; | |
825 | char *source; | |
826 | struct buffer_head *bh = jh2bh(jh); | |
827 | ||
828 | J_EXPECT_JH(jh, buffer_uptodate(bh), "Possible IO failure.\n"); | |
829 | page = bh->b_page; | |
830 | offset = offset_in_page(bh->b_data); | |
831 | source = kmap_atomic(page); | |
832 | /* Fire data frozen trigger just before we copy the data */ | |
833 | jbd2_buffer_frozen_trigger(jh, source + offset, jh->b_triggers); | |
834 | memcpy(jh->b_frozen_data, source + offset, bh->b_size); | |
835 | kunmap_atomic(source); | |
836 | ||
837 | /* | |
838 | * Now that the frozen data is saved off, we need to store any matching | |
839 | * triggers. | |
840 | */ | |
841 | jh->b_frozen_triggers = jh->b_triggers; | |
842 | } | |
843 | ||
470decc6 DK |
844 | /* |
845 | * If the buffer is already part of the current transaction, then there | |
846 | * is nothing we need to do. If it is already part of a prior | |
847 | * transaction which we are still committing to disk, then we need to | |
848 | * make sure that we do not overwrite the old copy: we do copy-out to | |
849 | * preserve the copy going to disk. We also account the buffer against | |
850 | * the handle's metadata buffer credits (unless the buffer is already | |
851 | * part of the transaction, that is). | |
852 | * | |
853 | */ | |
854 | static int | |
855 | do_get_write_access(handle_t *handle, struct journal_head *jh, | |
856 | int force_copy) | |
857 | { | |
858 | struct buffer_head *bh; | |
41a5b913 | 859 | transaction_t *transaction = handle->h_transaction; |
470decc6 DK |
860 | journal_t *journal; |
861 | int error; | |
862 | char *frozen_buffer = NULL; | |
f783f091 | 863 | unsigned long start_lock, time_lock; |
470decc6 DK |
864 | |
865 | if (is_handle_aborted(handle)) | |
866 | return -EROFS; | |
470decc6 DK |
867 | journal = transaction->t_journal; |
868 | ||
cfef2c6a | 869 | jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy); |
470decc6 DK |
870 | |
871 | JBUFFER_TRACE(jh, "entry"); | |
872 | repeat: | |
873 | bh = jh2bh(jh); | |
874 | ||
875 | /* @@@ Need to check for errors here at some point. */ | |
876 | ||
f783f091 | 877 | start_lock = jiffies; |
470decc6 DK |
878 | lock_buffer(bh); |
879 | jbd_lock_bh_state(bh); | |
880 | ||
f783f091 TT |
881 | /* If it takes too long to lock the buffer, trace it */ |
882 | time_lock = jbd2_time_diff(start_lock, jiffies); | |
883 | if (time_lock > HZ/10) | |
884 | trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev, | |
885 | jiffies_to_msecs(time_lock)); | |
886 | ||
470decc6 DK |
887 | /* We now hold the buffer lock so it is safe to query the buffer |
888 | * state. Is the buffer dirty? | |
889 | * | |
890 | * If so, there are two possibilities. The buffer may be | |
891 | * non-journaled, and undergoing a quite legitimate writeback. | |
892 | * Otherwise, it is journaled, and we don't expect dirty buffers | |
893 | * in that state (the buffers should be marked JBD_Dirty | |
894 | * instead.) So either the IO is being done under our own | |
895 | * control and this is a bug, or it's a third party IO such as | |
896 | * dump(8) (which may leave the buffer scheduled for read --- | |
897 | * ie. locked but not dirty) or tune2fs (which may actually have | |
898 | * the buffer dirtied, ugh.) */ | |
899 | ||
900 | if (buffer_dirty(bh)) { | |
901 | /* | |
902 | * First question: is this buffer already part of the current | |
903 | * transaction or the existing committing transaction? | |
904 | */ | |
905 | if (jh->b_transaction) { | |
906 | J_ASSERT_JH(jh, | |
907 | jh->b_transaction == transaction || | |
908 | jh->b_transaction == | |
909 | journal->j_committing_transaction); | |
910 | if (jh->b_next_transaction) | |
911 | J_ASSERT_JH(jh, jh->b_next_transaction == | |
912 | transaction); | |
f91d1d04 | 913 | warn_dirty_buffer(bh); |
470decc6 DK |
914 | } |
915 | /* | |
916 | * In any case we need to clean the dirty flag and we must | |
917 | * do it under the buffer lock to be sure we don't race | |
918 | * with running write-out. | |
919 | */ | |
f91d1d04 JK |
920 | JBUFFER_TRACE(jh, "Journalling dirty buffer"); |
921 | clear_buffer_dirty(bh); | |
922 | set_buffer_jbddirty(bh); | |
470decc6 DK |
923 | } |
924 | ||
925 | unlock_buffer(bh); | |
926 | ||
927 | error = -EROFS; | |
928 | if (is_handle_aborted(handle)) { | |
929 | jbd_unlock_bh_state(bh); | |
930 | goto out; | |
931 | } | |
932 | error = 0; | |
933 | ||
934 | /* | |
935 | * The buffer is already part of this transaction if b_transaction or | |
936 | * b_next_transaction points to it | |
937 | */ | |
938 | if (jh->b_transaction == transaction || | |
939 | jh->b_next_transaction == transaction) | |
940 | goto done; | |
941 | ||
9fc7c63a JB |
942 | /* |
943 | * this is the first time this transaction is touching this buffer, | |
944 | * reset the modified flag | |
945 | */ | |
561405f0 | 946 | jh->b_modified = 0; |
9fc7c63a | 947 | |
8b00f400 JK |
948 | /* |
949 | * If the buffer is not journaled right now, we need to make sure it | |
950 | * doesn't get written to disk before the caller actually commits the | |
951 | * new data | |
952 | */ | |
953 | if (!jh->b_transaction) { | |
954 | JBUFFER_TRACE(jh, "no transaction"); | |
955 | J_ASSERT_JH(jh, !jh->b_next_transaction); | |
956 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); | |
de92c8ca JK |
957 | /* |
958 | * Make sure all stores to jh (b_modified, b_frozen_data) are | |
959 | * visible before attaching it to the running transaction. | |
960 | * Paired with barrier in jbd2_write_access_granted() | |
961 | */ | |
962 | smp_wmb(); | |
8b00f400 JK |
963 | spin_lock(&journal->j_list_lock); |
964 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); | |
965 | spin_unlock(&journal->j_list_lock); | |
966 | goto done; | |
967 | } | |
470decc6 DK |
968 | /* |
969 | * If there is already a copy-out version of this buffer, then we don't | |
970 | * need to make another one | |
971 | */ | |
972 | if (jh->b_frozen_data) { | |
973 | JBUFFER_TRACE(jh, "has frozen data"); | |
974 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
de92c8ca | 975 | goto attach_next; |
470decc6 DK |
976 | } |
977 | ||
8b00f400 JK |
978 | JBUFFER_TRACE(jh, "owned by older transaction"); |
979 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
980 | J_ASSERT_JH(jh, jh->b_transaction == journal->j_committing_transaction); | |
470decc6 | 981 | |
8b00f400 JK |
982 | /* |
983 | * There is one case we have to be very careful about. If the | |
984 | * committing transaction is currently writing this buffer out to disk | |
985 | * and has NOT made a copy-out, then we cannot modify the buffer | |
986 | * contents at all right now. The essence of copy-out is that it is | |
987 | * the extra copy, not the primary copy, which gets journaled. If the | |
988 | * primary copy is already going to disk then we cannot do copy-out | |
989 | * here. | |
990 | */ | |
991 | if (buffer_shadow(bh)) { | |
992 | JBUFFER_TRACE(jh, "on shadow: sleep"); | |
993 | jbd_unlock_bh_state(bh); | |
994 | wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE); | |
995 | goto repeat; | |
996 | } | |
470decc6 | 997 | |
8b00f400 JK |
998 | /* |
999 | * Only do the copy if the currently-owning transaction still needs it. | |
1000 | * If buffer isn't on BJ_Metadata list, the committing transaction is | |
1001 | * past that stage (here we use the fact that BH_Shadow is set under | |
1002 | * bh_state lock together with refiling to BJ_Shadow list and at this | |
1003 | * point we know the buffer doesn't have BH_Shadow set). | |
1004 | * | |
1005 | * Subtle point, though: if this is a get_undo_access, then we will be | |
1006 | * relying on the frozen_data to contain the new value of the | |
1007 | * committed_data record after the transaction, so we HAVE to force the | |
1008 | * frozen_data copy in that case. | |
1009 | */ | |
1010 | if (jh->b_jlist == BJ_Metadata || force_copy) { | |
1011 | JBUFFER_TRACE(jh, "generate frozen data"); | |
1012 | if (!frozen_buffer) { | |
1013 | JBUFFER_TRACE(jh, "allocate memory for buffer"); | |
470decc6 | 1014 | jbd_unlock_bh_state(bh); |
490c1b44 MH |
1015 | frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size, |
1016 | GFP_NOFS | __GFP_NOFAIL); | |
8b00f400 | 1017 | goto repeat; |
470decc6 | 1018 | } |
8b00f400 JK |
1019 | jh->b_frozen_data = frozen_buffer; |
1020 | frozen_buffer = NULL; | |
1021 | jbd2_freeze_jh_data(jh); | |
470decc6 | 1022 | } |
de92c8ca JK |
1023 | attach_next: |
1024 | /* | |
1025 | * Make sure all stores to jh (b_modified, b_frozen_data) are visible | |
1026 | * before attaching it to the running transaction. Paired with barrier | |
1027 | * in jbd2_write_access_granted() | |
1028 | */ | |
1029 | smp_wmb(); | |
8b00f400 | 1030 | jh->b_next_transaction = transaction; |
470decc6 DK |
1031 | |
1032 | done: | |
470decc6 DK |
1033 | jbd_unlock_bh_state(bh); |
1034 | ||
1035 | /* | |
1036 | * If we are about to journal a buffer, then any revoke pending on it is | |
1037 | * no longer valid | |
1038 | */ | |
f7f4bccb | 1039 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 DK |
1040 | |
1041 | out: | |
1042 | if (unlikely(frozen_buffer)) /* It's usually NULL */ | |
af1e76d6 | 1043 | jbd2_free(frozen_buffer, bh->b_size); |
470decc6 DK |
1044 | |
1045 | JBUFFER_TRACE(jh, "exit"); | |
1046 | return error; | |
1047 | } | |
1048 | ||
de92c8ca | 1049 | /* Fast check whether buffer is already attached to the required transaction */ |
087ffd4e JB |
1050 | static bool jbd2_write_access_granted(handle_t *handle, struct buffer_head *bh, |
1051 | bool undo) | |
de92c8ca JK |
1052 | { |
1053 | struct journal_head *jh; | |
1054 | bool ret = false; | |
1055 | ||
1056 | /* Dirty buffers require special handling... */ | |
1057 | if (buffer_dirty(bh)) | |
1058 | return false; | |
1059 | ||
1060 | /* | |
1061 | * RCU protects us from dereferencing freed pages. So the checks we do | |
1062 | * are guaranteed not to oops. However the jh slab object can get freed | |
1063 | * & reallocated while we work with it. So we have to be careful. When | |
1064 | * we see jh attached to the running transaction, we know it must stay | |
1065 | * so until the transaction is committed. Thus jh won't be freed and | |
1066 | * will be attached to the same bh while we run. However it can | |
1067 | * happen jh gets freed, reallocated, and attached to the transaction | |
1068 | * just after we get pointer to it from bh. So we have to be careful | |
1069 | * and recheck jh still belongs to our bh before we return success. | |
1070 | */ | |
1071 | rcu_read_lock(); | |
1072 | if (!buffer_jbd(bh)) | |
1073 | goto out; | |
1074 | /* This should be bh2jh() but that doesn't work with inline functions */ | |
1075 | jh = READ_ONCE(bh->b_private); | |
1076 | if (!jh) | |
1077 | goto out; | |
087ffd4e JB |
1078 | /* For undo access buffer must have data copied */ |
1079 | if (undo && !jh->b_committed_data) | |
1080 | goto out; | |
de92c8ca JK |
1081 | if (jh->b_transaction != handle->h_transaction && |
1082 | jh->b_next_transaction != handle->h_transaction) | |
1083 | goto out; | |
1084 | /* | |
1085 | * There are two reasons for the barrier here: | |
1086 | * 1) Make sure to fetch b_bh after we did previous checks so that we | |
1087 | * detect when jh went through free, realloc, attach to transaction | |
1088 | * while we were checking. Paired with implicit barrier in that path. | |
1089 | * 2) So that access to bh done after jbd2_write_access_granted() | |
1090 | * doesn't get reordered and see inconsistent state of concurrent | |
1091 | * do_get_write_access(). | |
1092 | */ | |
1093 | smp_mb(); | |
1094 | if (unlikely(jh->b_bh != bh)) | |
1095 | goto out; | |
1096 | ret = true; | |
1097 | out: | |
1098 | rcu_read_unlock(); | |
1099 | return ret; | |
1100 | } | |
1101 | ||
470decc6 | 1102 | /** |
f7f4bccb | 1103 | * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update. |
470decc6 DK |
1104 | * @handle: transaction to add buffer modifications to |
1105 | * @bh: bh to be used for metadata writes | |
470decc6 | 1106 | * |
df1b560a | 1107 | * Returns: error code or 0 on success. |
470decc6 DK |
1108 | * |
1109 | * In full data journalling mode the buffer may be of type BJ_AsyncData, | |
df1b560a | 1110 | * because we're ``write()ing`` a buffer which is also part of a shared mapping. |
470decc6 DK |
1111 | */ |
1112 | ||
f7f4bccb | 1113 | int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
470decc6 | 1114 | { |
de92c8ca | 1115 | struct journal_head *jh; |
470decc6 DK |
1116 | int rc; |
1117 | ||
087ffd4e | 1118 | if (jbd2_write_access_granted(handle, bh, false)) |
de92c8ca JK |
1119 | return 0; |
1120 | ||
1121 | jh = jbd2_journal_add_journal_head(bh); | |
470decc6 DK |
1122 | /* We do not want to get caught playing with fields which the |
1123 | * log thread also manipulates. Make sure that the buffer | |
1124 | * completes any outstanding IO before proceeding. */ | |
1125 | rc = do_get_write_access(handle, jh, 0); | |
f7f4bccb | 1126 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1127 | return rc; |
1128 | } | |
1129 | ||
1130 | ||
1131 | /* | |
1132 | * When the user wants to journal a newly created buffer_head | |
1133 | * (ie. getblk() returned a new buffer and we are going to populate it | |
1134 | * manually rather than reading off disk), then we need to keep the | |
1135 | * buffer_head locked until it has been completely filled with new | |
1136 | * data. In this case, we should be able to make the assertion that | |
1137 | * the bh is not already part of an existing transaction. | |
1138 | * | |
1139 | * The buffer should already be locked by the caller by this point. | |
1140 | * There is no lock ranking violation: it was a newly created, | |
1141 | * unlocked buffer beforehand. */ | |
1142 | ||
1143 | /** | |
f7f4bccb | 1144 | * int jbd2_journal_get_create_access () - notify intent to use newly created bh |
470decc6 DK |
1145 | * @handle: transaction to new buffer to |
1146 | * @bh: new buffer. | |
1147 | * | |
1148 | * Call this if you create a new bh. | |
1149 | */ | |
f7f4bccb | 1150 | int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1151 | { |
1152 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1153 | journal_t *journal; |
f7f4bccb | 1154 | struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
470decc6 DK |
1155 | int err; |
1156 | ||
1157 | jbd_debug(5, "journal_head %p\n", jh); | |
1158 | err = -EROFS; | |
1159 | if (is_handle_aborted(handle)) | |
1160 | goto out; | |
41a5b913 | 1161 | journal = transaction->t_journal; |
470decc6 DK |
1162 | err = 0; |
1163 | ||
1164 | JBUFFER_TRACE(jh, "entry"); | |
1165 | /* | |
1166 | * The buffer may already belong to this transaction due to pre-zeroing | |
1167 | * in the filesystem's new_block code. It may also be on the previous, | |
1168 | * committing transaction's lists, but it HAS to be in Forget state in | |
1169 | * that case: the transaction must have deleted the buffer for it to be | |
1170 | * reused here. | |
1171 | */ | |
1172 | jbd_lock_bh_state(bh); | |
470decc6 DK |
1173 | J_ASSERT_JH(jh, (jh->b_transaction == transaction || |
1174 | jh->b_transaction == NULL || | |
1175 | (jh->b_transaction == journal->j_committing_transaction && | |
1176 | jh->b_jlist == BJ_Forget))); | |
1177 | ||
1178 | J_ASSERT_JH(jh, jh->b_next_transaction == NULL); | |
1179 | J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); | |
1180 | ||
1181 | if (jh->b_transaction == NULL) { | |
f91d1d04 JK |
1182 | /* |
1183 | * Previous jbd2_journal_forget() could have left the buffer | |
1184 | * with jbddirty bit set because it was being committed. When | |
1185 | * the commit finished, we've filed the buffer for | |
1186 | * checkpointing and marked it dirty. Now we are reallocating | |
1187 | * the buffer so the transaction freeing it must have | |
1188 | * committed and so it's safe to clear the dirty bit. | |
1189 | */ | |
1190 | clear_buffer_dirty(jh2bh(jh)); | |
9fc7c63a JB |
1191 | /* first access by this transaction */ |
1192 | jh->b_modified = 0; | |
1193 | ||
470decc6 | 1194 | JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
6e4862a5 | 1195 | spin_lock(&journal->j_list_lock); |
f7f4bccb | 1196 | __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
559cce69 | 1197 | spin_unlock(&journal->j_list_lock); |
470decc6 | 1198 | } else if (jh->b_transaction == journal->j_committing_transaction) { |
9fc7c63a JB |
1199 | /* first access by this transaction */ |
1200 | jh->b_modified = 0; | |
1201 | ||
470decc6 | 1202 | JBUFFER_TRACE(jh, "set next transaction"); |
6e4862a5 | 1203 | spin_lock(&journal->j_list_lock); |
470decc6 | 1204 | jh->b_next_transaction = transaction; |
559cce69 | 1205 | spin_unlock(&journal->j_list_lock); |
470decc6 | 1206 | } |
470decc6 DK |
1207 | jbd_unlock_bh_state(bh); |
1208 | ||
1209 | /* | |
1210 | * akpm: I added this. ext3_alloc_branch can pick up new indirect | |
1211 | * blocks which contain freed but then revoked metadata. We need | |
1212 | * to cancel the revoke in case we end up freeing it yet again | |
1213 | * and the reallocating as data - this would cause a second revoke, | |
1214 | * which hits an assertion error. | |
1215 | */ | |
1216 | JBUFFER_TRACE(jh, "cancelling revoke"); | |
f7f4bccb | 1217 | jbd2_journal_cancel_revoke(handle, jh); |
470decc6 | 1218 | out: |
3991b400 | 1219 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1220 | return err; |
1221 | } | |
1222 | ||
1223 | /** | |
f7f4bccb | 1224 | * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
470decc6 DK |
1225 | * non-rewindable consequences |
1226 | * @handle: transaction | |
1227 | * @bh: buffer to undo | |
470decc6 DK |
1228 | * |
1229 | * Sometimes there is a need to distinguish between metadata which has | |
1230 | * been committed to disk and that which has not. The ext3fs code uses | |
1231 | * this for freeing and allocating space, we have to make sure that we | |
1232 | * do not reuse freed space until the deallocation has been committed, | |
1233 | * since if we overwrote that space we would make the delete | |
1234 | * un-rewindable in case of a crash. | |
1235 | * | |
f7f4bccb | 1236 | * To deal with that, jbd2_journal_get_undo_access requests write access to a |
470decc6 DK |
1237 | * buffer for parts of non-rewindable operations such as delete |
1238 | * operations on the bitmaps. The journaling code must keep a copy of | |
1239 | * the buffer's contents prior to the undo_access call until such time | |
1240 | * as we know that the buffer has definitely been committed to disk. | |
1241 | * | |
1242 | * We never need to know which transaction the committed data is part | |
1243 | * of, buffers touched here are guaranteed to be dirtied later and so | |
1244 | * will be committed to a new transaction in due course, at which point | |
1245 | * we can discard the old committed data pointer. | |
1246 | * | |
1247 | * Returns error number or 0 on success. | |
1248 | */ | |
f7f4bccb | 1249 | int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1250 | { |
1251 | int err; | |
de92c8ca | 1252 | struct journal_head *jh; |
470decc6 DK |
1253 | char *committed_data = NULL; |
1254 | ||
087ffd4e | 1255 | if (jbd2_write_access_granted(handle, bh, true)) |
de92c8ca | 1256 | return 0; |
470decc6 | 1257 | |
de92c8ca | 1258 | jh = jbd2_journal_add_journal_head(bh); |
01215d3e | 1259 | JBUFFER_TRACE(jh, "entry"); |
1260 | ||
470decc6 DK |
1261 | /* |
1262 | * Do this first --- it can drop the journal lock, so we want to | |
1263 | * make sure that obtaining the committed_data is done | |
1264 | * atomically wrt. completion of any outstanding commits. | |
1265 | */ | |
1266 | err = do_get_write_access(handle, jh, 1); | |
1267 | if (err) | |
1268 | goto out; | |
1269 | ||
1270 | repeat: | |
490c1b44 MH |
1271 | if (!jh->b_committed_data) |
1272 | committed_data = jbd2_alloc(jh2bh(jh)->b_size, | |
1273 | GFP_NOFS|__GFP_NOFAIL); | |
470decc6 DK |
1274 | |
1275 | jbd_lock_bh_state(bh); | |
1276 | if (!jh->b_committed_data) { | |
1277 | /* Copy out the current buffer contents into the | |
1278 | * preserved, committed copy. */ | |
1279 | JBUFFER_TRACE(jh, "generate b_committed data"); | |
1280 | if (!committed_data) { | |
1281 | jbd_unlock_bh_state(bh); | |
1282 | goto repeat; | |
1283 | } | |
1284 | ||
1285 | jh->b_committed_data = committed_data; | |
1286 | committed_data = NULL; | |
1287 | memcpy(jh->b_committed_data, bh->b_data, bh->b_size); | |
1288 | } | |
1289 | jbd_unlock_bh_state(bh); | |
1290 | out: | |
f7f4bccb | 1291 | jbd2_journal_put_journal_head(jh); |
470decc6 | 1292 | if (unlikely(committed_data)) |
af1e76d6 | 1293 | jbd2_free(committed_data, bh->b_size); |
470decc6 DK |
1294 | return err; |
1295 | } | |
1296 | ||
e06c8227 JB |
1297 | /** |
1298 | * void jbd2_journal_set_triggers() - Add triggers for commit writeout | |
1299 | * @bh: buffer to trigger on | |
1300 | * @type: struct jbd2_buffer_trigger_type containing the trigger(s). | |
1301 | * | |
1302 | * Set any triggers on this journal_head. This is always safe, because | |
1303 | * triggers for a committing buffer will be saved off, and triggers for | |
1304 | * a running transaction will match the buffer in that transaction. | |
1305 | * | |
1306 | * Call with NULL to clear the triggers. | |
1307 | */ | |
1308 | void jbd2_journal_set_triggers(struct buffer_head *bh, | |
1309 | struct jbd2_buffer_trigger_type *type) | |
1310 | { | |
ad56edad | 1311 | struct journal_head *jh = jbd2_journal_grab_journal_head(bh); |
e06c8227 | 1312 | |
ad56edad JK |
1313 | if (WARN_ON(!jh)) |
1314 | return; | |
e06c8227 | 1315 | jh->b_triggers = type; |
ad56edad | 1316 | jbd2_journal_put_journal_head(jh); |
e06c8227 JB |
1317 | } |
1318 | ||
13ceef09 | 1319 | void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data, |
e06c8227 JB |
1320 | struct jbd2_buffer_trigger_type *triggers) |
1321 | { | |
1322 | struct buffer_head *bh = jh2bh(jh); | |
1323 | ||
13ceef09 | 1324 | if (!triggers || !triggers->t_frozen) |
e06c8227 JB |
1325 | return; |
1326 | ||
13ceef09 | 1327 | triggers->t_frozen(triggers, bh, mapped_data, bh->b_size); |
e06c8227 JB |
1328 | } |
1329 | ||
1330 | void jbd2_buffer_abort_trigger(struct journal_head *jh, | |
1331 | struct jbd2_buffer_trigger_type *triggers) | |
1332 | { | |
1333 | if (!triggers || !triggers->t_abort) | |
1334 | return; | |
1335 | ||
1336 | triggers->t_abort(triggers, jh2bh(jh)); | |
1337 | } | |
1338 | ||
470decc6 | 1339 | /** |
f7f4bccb | 1340 | * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
470decc6 DK |
1341 | * @handle: transaction to add buffer to. |
1342 | * @bh: buffer to mark | |
1343 | * | |
1344 | * mark dirty metadata which needs to be journaled as part of the current | |
1345 | * transaction. | |
1346 | * | |
9ea7a0df TT |
1347 | * The buffer must have previously had jbd2_journal_get_write_access() |
1348 | * called so that it has a valid journal_head attached to the buffer | |
1349 | * head. | |
1350 | * | |
470decc6 DK |
1351 | * The buffer is placed on the transaction's metadata list and is marked |
1352 | * as belonging to the transaction. | |
1353 | * | |
1354 | * Returns error number or 0 on success. | |
1355 | * | |
1356 | * Special care needs to be taken if the buffer already belongs to the | |
1357 | * current committing transaction (in which case we should have frozen | |
1358 | * data present for that commit). In that case, we don't relink the | |
1359 | * buffer: that only gets done when the old transaction finally | |
1360 | * completes its commit. | |
1361 | */ | |
f7f4bccb | 1362 | int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1363 | { |
1364 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1365 | journal_t *journal; |
ad56edad | 1366 | struct journal_head *jh; |
9ea7a0df | 1367 | int ret = 0; |
470decc6 | 1368 | |
470decc6 | 1369 | if (is_handle_aborted(handle)) |
41a5b913 | 1370 | return -EROFS; |
01215d3e | 1371 | if (!buffer_jbd(bh)) |
1372 | return -EUCLEAN; | |
1373 | ||
6e06ae88 JK |
1374 | /* |
1375 | * We don't grab jh reference here since the buffer must be part | |
1376 | * of the running transaction. | |
1377 | */ | |
1378 | jh = bh2jh(bh); | |
01215d3e | 1379 | jbd_debug(5, "journal_head %p\n", jh); |
1380 | JBUFFER_TRACE(jh, "entry"); | |
1381 | ||
6e06ae88 JK |
1382 | /* |
1383 | * This and the following assertions are unreliable since we may see jh | |
1384 | * in inconsistent state unless we grab bh_state lock. But this is | |
1385 | * crucial to catch bugs so let's do a reliable check until the | |
1386 | * lockless handling is fully proven. | |
1387 | */ | |
1388 | if (jh->b_transaction != transaction && | |
1389 | jh->b_next_transaction != transaction) { | |
1390 | jbd_lock_bh_state(bh); | |
1391 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
1392 | jh->b_next_transaction == transaction); | |
1393 | jbd_unlock_bh_state(bh); | |
1394 | } | |
1395 | if (jh->b_modified == 1) { | |
1396 | /* If it's in our transaction it must be in BJ_Metadata list. */ | |
1397 | if (jh->b_transaction == transaction && | |
1398 | jh->b_jlist != BJ_Metadata) { | |
1399 | jbd_lock_bh_state(bh); | |
e09463f2 TT |
1400 | if (jh->b_transaction == transaction && |
1401 | jh->b_jlist != BJ_Metadata) | |
1402 | pr_err("JBD2: assertion failure: h_type=%u " | |
1403 | "h_line_no=%u block_no=%llu jlist=%u\n", | |
1404 | handle->h_type, handle->h_line_no, | |
1405 | (unsigned long long) bh->b_blocknr, | |
1406 | jh->b_jlist); | |
6e06ae88 JK |
1407 | J_ASSERT_JH(jh, jh->b_transaction != transaction || |
1408 | jh->b_jlist == BJ_Metadata); | |
1409 | jbd_unlock_bh_state(bh); | |
1410 | } | |
1411 | goto out; | |
1412 | } | |
1413 | ||
1414 | journal = transaction->t_journal; | |
470decc6 DK |
1415 | jbd_lock_bh_state(bh); |
1416 | ||
1417 | if (jh->b_modified == 0) { | |
1418 | /* | |
1419 | * This buffer's got modified and becoming part | |
1420 | * of the transaction. This needs to be done | |
1421 | * once a transaction -bzzz | |
1422 | */ | |
f6c07cad TT |
1423 | if (handle->h_buffer_credits <= 0) { |
1424 | ret = -ENOSPC; | |
1425 | goto out_unlock_bh; | |
1426 | } | |
e09463f2 | 1427 | jh->b_modified = 1; |
470decc6 DK |
1428 | handle->h_buffer_credits--; |
1429 | } | |
1430 | ||
1431 | /* | |
1432 | * fastpath, to avoid expensive locking. If this buffer is already | |
1433 | * on the running transaction's metadata list there is nothing to do. | |
1434 | * Nobody can take it off again because there is a handle open. | |
1435 | * I _think_ we're OK here with SMP barriers - a mistaken decision will | |
1436 | * result in this test being false, so we go in and take the locks. | |
1437 | */ | |
1438 | if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { | |
1439 | JBUFFER_TRACE(jh, "fastpath"); | |
9ea7a0df TT |
1440 | if (unlikely(jh->b_transaction != |
1441 | journal->j_running_transaction)) { | |
a67c848a | 1442 | printk(KERN_ERR "JBD2: %s: " |
9ea7a0df | 1443 | "jh->b_transaction (%llu, %p, %u) != " |
66a4cb18 | 1444 | "journal->j_running_transaction (%p, %u)\n", |
9ea7a0df TT |
1445 | journal->j_devname, |
1446 | (unsigned long long) bh->b_blocknr, | |
1447 | jh->b_transaction, | |
1448 | jh->b_transaction ? jh->b_transaction->t_tid : 0, | |
1449 | journal->j_running_transaction, | |
1450 | journal->j_running_transaction ? | |
1451 | journal->j_running_transaction->t_tid : 0); | |
1452 | ret = -EINVAL; | |
1453 | } | |
470decc6 DK |
1454 | goto out_unlock_bh; |
1455 | } | |
1456 | ||
1457 | set_buffer_jbddirty(bh); | |
1458 | ||
1459 | /* | |
1460 | * Metadata already on the current transaction list doesn't | |
1461 | * need to be filed. Metadata on another transaction's list must | |
1462 | * be committing, and will be refiled once the commit completes: | |
1463 | * leave it alone for now. | |
1464 | */ | |
1465 | if (jh->b_transaction != transaction) { | |
1466 | JBUFFER_TRACE(jh, "already on other transaction"); | |
66a4cb18 TT |
1467 | if (unlikely(((jh->b_transaction != |
1468 | journal->j_committing_transaction)) || | |
1469 | (jh->b_next_transaction != transaction))) { | |
1470 | printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: " | |
1471 | "bad jh for block %llu: " | |
1472 | "transaction (%p, %u), " | |
1473 | "jh->b_transaction (%p, %u), " | |
1474 | "jh->b_next_transaction (%p, %u), jlist %u\n", | |
9ea7a0df TT |
1475 | journal->j_devname, |
1476 | (unsigned long long) bh->b_blocknr, | |
66a4cb18 | 1477 | transaction, transaction->t_tid, |
9ea7a0df | 1478 | jh->b_transaction, |
66a4cb18 TT |
1479 | jh->b_transaction ? |
1480 | jh->b_transaction->t_tid : 0, | |
9ea7a0df TT |
1481 | jh->b_next_transaction, |
1482 | jh->b_next_transaction ? | |
1483 | jh->b_next_transaction->t_tid : 0, | |
66a4cb18 TT |
1484 | jh->b_jlist); |
1485 | WARN_ON(1); | |
9ea7a0df TT |
1486 | ret = -EINVAL; |
1487 | } | |
470decc6 DK |
1488 | /* And this case is illegal: we can't reuse another |
1489 | * transaction's data buffer, ever. */ | |
1490 | goto out_unlock_bh; | |
1491 | } | |
1492 | ||
1493 | /* That test should have eliminated the following case: */ | |
4019191b | 1494 | J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
470decc6 DK |
1495 | |
1496 | JBUFFER_TRACE(jh, "file as BJ_Metadata"); | |
1497 | spin_lock(&journal->j_list_lock); | |
41a5b913 | 1498 | __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata); |
470decc6 DK |
1499 | spin_unlock(&journal->j_list_lock); |
1500 | out_unlock_bh: | |
1501 | jbd_unlock_bh_state(bh); | |
1502 | out: | |
1503 | JBUFFER_TRACE(jh, "exit"); | |
9ea7a0df | 1504 | return ret; |
470decc6 DK |
1505 | } |
1506 | ||
470decc6 | 1507 | /** |
f7f4bccb | 1508 | * void jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
470decc6 DK |
1509 | * @handle: transaction handle |
1510 | * @bh: bh to 'forget' | |
1511 | * | |
1512 | * We can only do the bforget if there are no commits pending against the | |
1513 | * buffer. If the buffer is dirty in the current running transaction we | |
1514 | * can safely unlink it. | |
1515 | * | |
1516 | * bh may not be a journalled buffer at all - it may be a non-JBD | |
1517 | * buffer which came off the hashtable. Check for this. | |
1518 | * | |
1519 | * Decrements bh->b_count by one. | |
1520 | * | |
1521 | * Allow this call even if the handle has aborted --- it may be part of | |
1522 | * the caller's cleanup after an abort. | |
1523 | */ | |
f7f4bccb | 1524 | int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) |
470decc6 DK |
1525 | { |
1526 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 1527 | journal_t *journal; |
470decc6 DK |
1528 | struct journal_head *jh; |
1529 | int drop_reserve = 0; | |
1530 | int err = 0; | |
1dfc3220 | 1531 | int was_modified = 0; |
470decc6 | 1532 | |
41a5b913 TT |
1533 | if (is_handle_aborted(handle)) |
1534 | return -EROFS; | |
1535 | journal = transaction->t_journal; | |
1536 | ||
470decc6 DK |
1537 | BUFFER_TRACE(bh, "entry"); |
1538 | ||
1539 | jbd_lock_bh_state(bh); | |
470decc6 DK |
1540 | |
1541 | if (!buffer_jbd(bh)) | |
1542 | goto not_jbd; | |
1543 | jh = bh2jh(bh); | |
1544 | ||
1545 | /* Critical error: attempting to delete a bitmap buffer, maybe? | |
1546 | * Don't do any jbd operations, and return an error. */ | |
1547 | if (!J_EXPECT_JH(jh, !jh->b_committed_data, | |
1548 | "inconsistent data on disk")) { | |
1549 | err = -EIO; | |
1550 | goto not_jbd; | |
1551 | } | |
1552 | ||
48fc7f7e | 1553 | /* keep track of whether or not this transaction modified us */ |
1dfc3220 JB |
1554 | was_modified = jh->b_modified; |
1555 | ||
470decc6 DK |
1556 | /* |
1557 | * The buffer's going from the transaction, we must drop | |
1558 | * all references -bzzz | |
1559 | */ | |
1560 | jh->b_modified = 0; | |
1561 | ||
41a5b913 | 1562 | if (jh->b_transaction == transaction) { |
470decc6 DK |
1563 | J_ASSERT_JH(jh, !jh->b_frozen_data); |
1564 | ||
1565 | /* If we are forgetting a buffer which is already part | |
1566 | * of this transaction, then we can just drop it from | |
1567 | * the transaction immediately. */ | |
1568 | clear_buffer_dirty(bh); | |
1569 | clear_buffer_jbddirty(bh); | |
1570 | ||
1571 | JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); | |
1572 | ||
1dfc3220 JB |
1573 | /* |
1574 | * we only want to drop a reference if this transaction | |
1575 | * modified the buffer | |
1576 | */ | |
1577 | if (was_modified) | |
1578 | drop_reserve = 1; | |
470decc6 DK |
1579 | |
1580 | /* | |
1581 | * We are no longer going to journal this buffer. | |
1582 | * However, the commit of this transaction is still | |
1583 | * important to the buffer: the delete that we are now | |
1584 | * processing might obsolete an old log entry, so by | |
1585 | * committing, we can satisfy the buffer's checkpoint. | |
1586 | * | |
1587 | * So, if we have a checkpoint on the buffer, we should | |
1588 | * now refile the buffer on our BJ_Forget list so that | |
1589 | * we know to remove the checkpoint after we commit. | |
1590 | */ | |
1591 | ||
0bfea811 | 1592 | spin_lock(&journal->j_list_lock); |
470decc6 | 1593 | if (jh->b_cp_transaction) { |
f7f4bccb MC |
1594 | __jbd2_journal_temp_unlink_buffer(jh); |
1595 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
470decc6 | 1596 | } else { |
f7f4bccb | 1597 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
1598 | if (!buffer_jbd(bh)) { |
1599 | spin_unlock(&journal->j_list_lock); | |
59759926 | 1600 | goto not_jbd; |
470decc6 DK |
1601 | } |
1602 | } | |
0bfea811 | 1603 | spin_unlock(&journal->j_list_lock); |
470decc6 DK |
1604 | } else if (jh->b_transaction) { |
1605 | J_ASSERT_JH(jh, (jh->b_transaction == | |
1606 | journal->j_committing_transaction)); | |
1607 | /* However, if the buffer is still owned by a prior | |
1608 | * (committing) transaction, we can't drop it yet... */ | |
1609 | JBUFFER_TRACE(jh, "belongs to older transaction"); | |
904cdbd4 | 1610 | /* ... but we CAN drop it from the new transaction through |
1611 | * marking the buffer as freed and set j_next_transaction to | |
1612 | * the new transaction, so that not only the commit code | |
1613 | * knows it should clear dirty bits when it is done with the | |
1614 | * buffer, but also the buffer can be checkpointed only | |
1615 | * after the new transaction commits. */ | |
470decc6 | 1616 | |
904cdbd4 | 1617 | set_buffer_freed(bh); |
1618 | ||
1619 | if (!jh->b_next_transaction) { | |
0bfea811 | 1620 | spin_lock(&journal->j_list_lock); |
904cdbd4 | 1621 | jh->b_next_transaction = transaction; |
0bfea811 | 1622 | spin_unlock(&journal->j_list_lock); |
904cdbd4 | 1623 | } else { |
1624 | J_ASSERT(jh->b_next_transaction == transaction); | |
1dfc3220 JB |
1625 | |
1626 | /* | |
1627 | * only drop a reference if this transaction modified | |
1628 | * the buffer | |
1629 | */ | |
1630 | if (was_modified) | |
1631 | drop_reserve = 1; | |
470decc6 | 1632 | } |
59759926 | 1633 | } else { |
1634 | /* | |
1635 | * Finally, if the buffer is not belongs to any | |
1636 | * transaction, we can just drop it now if it has no | |
1637 | * checkpoint. | |
1638 | */ | |
1639 | spin_lock(&journal->j_list_lock); | |
1640 | if (!jh->b_cp_transaction) { | |
1641 | JBUFFER_TRACE(jh, "belongs to none transaction"); | |
1642 | spin_unlock(&journal->j_list_lock); | |
1643 | goto not_jbd; | |
1644 | } | |
1645 | ||
1646 | /* | |
1647 | * Otherwise, if the buffer has been written to disk, | |
1648 | * it is safe to remove the checkpoint and drop it. | |
1649 | */ | |
1650 | if (!buffer_dirty(bh)) { | |
1651 | __jbd2_journal_remove_checkpoint(jh); | |
1652 | spin_unlock(&journal->j_list_lock); | |
1653 | goto not_jbd; | |
1654 | } | |
1655 | ||
1656 | /* | |
1657 | * The buffer is still not written to disk, we should | |
1658 | * attach this buffer to current transaction so that the | |
1659 | * buffer can be checkpointed only after the current | |
1660 | * transaction commits. | |
1661 | */ | |
1662 | clear_buffer_dirty(bh); | |
1663 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); | |
1664 | spin_unlock(&journal->j_list_lock); | |
470decc6 DK |
1665 | } |
1666 | ||
470decc6 DK |
1667 | jbd_unlock_bh_state(bh); |
1668 | __brelse(bh); | |
1669 | drop: | |
1670 | if (drop_reserve) { | |
1671 | /* no need to reserve log space for this block -bzzz */ | |
1672 | handle->h_buffer_credits++; | |
1673 | } | |
1674 | return err; | |
59759926 | 1675 | |
1676 | not_jbd: | |
1677 | jbd_unlock_bh_state(bh); | |
1678 | __bforget(bh); | |
1679 | goto drop; | |
470decc6 DK |
1680 | } |
1681 | ||
1682 | /** | |
f7f4bccb | 1683 | * int jbd2_journal_stop() - complete a transaction |
bd7ced98 | 1684 | * @handle: transaction to complete. |
470decc6 DK |
1685 | * |
1686 | * All done for a particular handle. | |
1687 | * | |
1688 | * There is not much action needed here. We just return any remaining | |
1689 | * buffer credits to the transaction and remove the handle. The only | |
1690 | * complication is that we need to start a commit operation if the | |
1691 | * filesystem is marked for synchronous update. | |
1692 | * | |
f7f4bccb | 1693 | * jbd2_journal_stop itself will not usually return an error, but it may |
470decc6 | 1694 | * do so in unusual circumstances. In particular, expect it to |
f7f4bccb | 1695 | * return -EIO if a jbd2_journal_abort has been executed since the |
470decc6 DK |
1696 | * transaction began. |
1697 | */ | |
f7f4bccb | 1698 | int jbd2_journal_stop(handle_t *handle) |
470decc6 DK |
1699 | { |
1700 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 TT |
1701 | journal_t *journal; |
1702 | int err = 0, wait_for_commit = 0; | |
a51dca9c | 1703 | tid_t tid; |
470decc6 DK |
1704 | pid_t pid; |
1705 | ||
9d506594 LC |
1706 | if (!transaction) { |
1707 | /* | |
1708 | * Handle is already detached from the transaction so | |
1709 | * there is nothing to do other than decrease a refcount, | |
1710 | * or free the handle if refcount drops to zero | |
1711 | */ | |
1712 | if (--handle->h_ref > 0) { | |
1713 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1714 | handle->h_ref); | |
1715 | return err; | |
1716 | } else { | |
1717 | if (handle->h_rsv_handle) | |
1718 | jbd2_free_handle(handle->h_rsv_handle); | |
1719 | goto free_and_exit; | |
1720 | } | |
1721 | } | |
41a5b913 TT |
1722 | journal = transaction->t_journal; |
1723 | ||
470decc6 DK |
1724 | J_ASSERT(journal_current_handle() == handle); |
1725 | ||
1726 | if (is_handle_aborted(handle)) | |
1727 | err = -EIO; | |
41a5b913 | 1728 | else |
a51dca9c | 1729 | J_ASSERT(atomic_read(&transaction->t_updates) > 0); |
470decc6 DK |
1730 | |
1731 | if (--handle->h_ref > 0) { | |
1732 | jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, | |
1733 | handle->h_ref); | |
1734 | return err; | |
1735 | } | |
1736 | ||
1737 | jbd_debug(4, "Handle %p going down\n", handle); | |
343d9c28 | 1738 | trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev, |
41a5b913 | 1739 | transaction->t_tid, |
343d9c28 TT |
1740 | handle->h_type, handle->h_line_no, |
1741 | jiffies - handle->h_start_jiffies, | |
1742 | handle->h_sync, handle->h_requested_credits, | |
1743 | (handle->h_requested_credits - | |
1744 | handle->h_buffer_credits)); | |
470decc6 DK |
1745 | |
1746 | /* | |
1747 | * Implement synchronous transaction batching. If the handle | |
1748 | * was synchronous, don't force a commit immediately. Let's | |
e07f7183 JB |
1749 | * yield and let another thread piggyback onto this |
1750 | * transaction. Keep doing that while new threads continue to | |
1751 | * arrive. It doesn't cost much - we're about to run a commit | |
1752 | * and sleep on IO anyway. Speeds up many-threaded, many-dir | |
1753 | * operations by 30x or more... | |
1754 | * | |
1755 | * We try and optimize the sleep time against what the | |
1756 | * underlying disk can do, instead of having a static sleep | |
1757 | * time. This is useful for the case where our storage is so | |
1758 | * fast that it is more optimal to go ahead and force a flush | |
1759 | * and wait for the transaction to be committed than it is to | |
1760 | * wait for an arbitrary amount of time for new writers to | |
1761 | * join the transaction. We achieve this by measuring how | |
1762 | * long it takes to commit a transaction, and compare it with | |
1763 | * how long this transaction has been running, and if run time | |
1764 | * < commit time then we sleep for the delta and commit. This | |
1765 | * greatly helps super fast disks that would see slowdowns as | |
1766 | * more threads started doing fsyncs. | |
470decc6 | 1767 | * |
e07f7183 JB |
1768 | * But don't do this if this process was the most recent one |
1769 | * to perform a synchronous write. We do this to detect the | |
1770 | * case where a single process is doing a stream of sync | |
1771 | * writes. No point in waiting for joiners in that case. | |
5dd21424 ES |
1772 | * |
1773 | * Setting max_batch_time to 0 disables this completely. | |
470decc6 DK |
1774 | */ |
1775 | pid = current->pid; | |
5dd21424 ES |
1776 | if (handle->h_sync && journal->j_last_sync_writer != pid && |
1777 | journal->j_max_batch_time) { | |
e07f7183 JB |
1778 | u64 commit_time, trans_time; |
1779 | ||
470decc6 | 1780 | journal->j_last_sync_writer = pid; |
e07f7183 | 1781 | |
a931da6a | 1782 | read_lock(&journal->j_state_lock); |
e07f7183 | 1783 | commit_time = journal->j_average_commit_time; |
a931da6a | 1784 | read_unlock(&journal->j_state_lock); |
e07f7183 JB |
1785 | |
1786 | trans_time = ktime_to_ns(ktime_sub(ktime_get(), | |
1787 | transaction->t_start_time)); | |
1788 | ||
30773840 TT |
1789 | commit_time = max_t(u64, commit_time, |
1790 | 1000*journal->j_min_batch_time); | |
e07f7183 | 1791 | commit_time = min_t(u64, commit_time, |
30773840 | 1792 | 1000*journal->j_max_batch_time); |
e07f7183 JB |
1793 | |
1794 | if (trans_time < commit_time) { | |
1795 | ktime_t expires = ktime_add_ns(ktime_get(), | |
1796 | commit_time); | |
1797 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1798 | schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); | |
1799 | } | |
470decc6 DK |
1800 | } |
1801 | ||
7058548c TT |
1802 | if (handle->h_sync) |
1803 | transaction->t_synchronous_commit = 1; | |
470decc6 | 1804 | current->journal_info = NULL; |
a51dca9c TT |
1805 | atomic_sub(handle->h_buffer_credits, |
1806 | &transaction->t_outstanding_credits); | |
470decc6 DK |
1807 | |
1808 | /* | |
1809 | * If the handle is marked SYNC, we need to set another commit | |
1810 | * going! We also want to force a commit if the current | |
1811 | * transaction is occupying too much of the log, or if the | |
1812 | * transaction is too old now. | |
1813 | */ | |
1814 | if (handle->h_sync || | |
a51dca9c TT |
1815 | (atomic_read(&transaction->t_outstanding_credits) > |
1816 | journal->j_max_transaction_buffers) || | |
1817 | time_after_eq(jiffies, transaction->t_expires)) { | |
470decc6 DK |
1818 | /* Do this even for aborted journals: an abort still |
1819 | * completes the commit thread, it just doesn't write | |
1820 | * anything to disk. */ | |
470decc6 | 1821 | |
470decc6 DK |
1822 | jbd_debug(2, "transaction too old, requesting commit for " |
1823 | "handle %p\n", handle); | |
1824 | /* This is non-blocking */ | |
c35a56a0 | 1825 | jbd2_log_start_commit(journal, transaction->t_tid); |
470decc6 DK |
1826 | |
1827 | /* | |
f7f4bccb | 1828 | * Special case: JBD2_SYNC synchronous updates require us |
470decc6 DK |
1829 | * to wait for the commit to complete. |
1830 | */ | |
1831 | if (handle->h_sync && !(current->flags & PF_MEMALLOC)) | |
a51dca9c | 1832 | wait_for_commit = 1; |
470decc6 DK |
1833 | } |
1834 | ||
a51dca9c TT |
1835 | /* |
1836 | * Once we drop t_updates, if it goes to zero the transaction | |
25985edc | 1837 | * could start committing on us and eventually disappear. So |
a51dca9c TT |
1838 | * once we do this, we must not dereference transaction |
1839 | * pointer again. | |
1840 | */ | |
1841 | tid = transaction->t_tid; | |
1842 | if (atomic_dec_and_test(&transaction->t_updates)) { | |
1843 | wake_up(&journal->j_wait_updates); | |
1844 | if (journal->j_barrier_count) | |
1845 | wake_up(&journal->j_wait_transaction_locked); | |
1846 | } | |
1847 | ||
ab714aff | 1848 | rwsem_release(&journal->j_trans_commit_map, 1, _THIS_IP_); |
7a4b188f | 1849 | |
a51dca9c TT |
1850 | if (wait_for_commit) |
1851 | err = jbd2_log_wait_commit(journal, tid); | |
1852 | ||
8f7d89f3 JK |
1853 | if (handle->h_rsv_handle) |
1854 | jbd2_journal_free_reserved(handle->h_rsv_handle); | |
41a5b913 | 1855 | free_and_exit: |
81378da6 MH |
1856 | /* |
1857 | * Scope of the GFP_NOFS context is over here and so we can restore the | |
1858 | * original alloc context. | |
1859 | */ | |
1860 | memalloc_nofs_restore(handle->saved_alloc_context); | |
af1e76d6 | 1861 | jbd2_free_handle(handle); |
470decc6 DK |
1862 | return err; |
1863 | } | |
1864 | ||
470decc6 DK |
1865 | /* |
1866 | * | |
1867 | * List management code snippets: various functions for manipulating the | |
1868 | * transaction buffer lists. | |
1869 | * | |
1870 | */ | |
1871 | ||
1872 | /* | |
1873 | * Append a buffer to a transaction list, given the transaction's list head | |
1874 | * pointer. | |
1875 | * | |
1876 | * j_list_lock is held. | |
1877 | * | |
1878 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1879 | */ | |
1880 | ||
1881 | static inline void | |
1882 | __blist_add_buffer(struct journal_head **list, struct journal_head *jh) | |
1883 | { | |
1884 | if (!*list) { | |
1885 | jh->b_tnext = jh->b_tprev = jh; | |
1886 | *list = jh; | |
1887 | } else { | |
1888 | /* Insert at the tail of the list to preserve order */ | |
1889 | struct journal_head *first = *list, *last = first->b_tprev; | |
1890 | jh->b_tprev = last; | |
1891 | jh->b_tnext = first; | |
1892 | last->b_tnext = first->b_tprev = jh; | |
1893 | } | |
1894 | } | |
1895 | ||
1896 | /* | |
1897 | * Remove a buffer from a transaction list, given the transaction's list | |
1898 | * head pointer. | |
1899 | * | |
1900 | * Called with j_list_lock held, and the journal may not be locked. | |
1901 | * | |
1902 | * jbd_lock_bh_state(jh2bh(jh)) is held. | |
1903 | */ | |
1904 | ||
1905 | static inline void | |
1906 | __blist_del_buffer(struct journal_head **list, struct journal_head *jh) | |
1907 | { | |
1908 | if (*list == jh) { | |
1909 | *list = jh->b_tnext; | |
1910 | if (*list == jh) | |
1911 | *list = NULL; | |
1912 | } | |
1913 | jh->b_tprev->b_tnext = jh->b_tnext; | |
1914 | jh->b_tnext->b_tprev = jh->b_tprev; | |
1915 | } | |
1916 | ||
1917 | /* | |
1918 | * Remove a buffer from the appropriate transaction list. | |
1919 | * | |
1920 | * Note that this function can *change* the value of | |
f5113eff JK |
1921 | * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or |
1922 | * t_reserved_list. If the caller is holding onto a copy of one of these | |
1923 | * pointers, it could go bad. Generally the caller needs to re-read the | |
1924 | * pointer from the transaction_t. | |
470decc6 | 1925 | * |
5bebccf9 | 1926 | * Called under j_list_lock. |
470decc6 | 1927 | */ |
5bebccf9 | 1928 | static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
470decc6 DK |
1929 | { |
1930 | struct journal_head **list = NULL; | |
1931 | transaction_t *transaction; | |
1932 | struct buffer_head *bh = jh2bh(jh); | |
1933 | ||
1934 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
1935 | transaction = jh->b_transaction; | |
1936 | if (transaction) | |
1937 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
1938 | ||
1939 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
1940 | if (jh->b_jlist != BJ_None) | |
4019191b | 1941 | J_ASSERT_JH(jh, transaction != NULL); |
470decc6 DK |
1942 | |
1943 | switch (jh->b_jlist) { | |
1944 | case BJ_None: | |
1945 | return; | |
470decc6 DK |
1946 | case BJ_Metadata: |
1947 | transaction->t_nr_buffers--; | |
1948 | J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); | |
1949 | list = &transaction->t_buffers; | |
1950 | break; | |
1951 | case BJ_Forget: | |
1952 | list = &transaction->t_forget; | |
1953 | break; | |
470decc6 DK |
1954 | case BJ_Shadow: |
1955 | list = &transaction->t_shadow_list; | |
1956 | break; | |
470decc6 DK |
1957 | case BJ_Reserved: |
1958 | list = &transaction->t_reserved_list; | |
1959 | break; | |
470decc6 DK |
1960 | } |
1961 | ||
1962 | __blist_del_buffer(list, jh); | |
1963 | jh->b_jlist = BJ_None; | |
e112666b TT |
1964 | if (transaction && is_journal_aborted(transaction->t_journal)) |
1965 | clear_buffer_jbddirty(bh); | |
1966 | else if (test_clear_buffer_jbddirty(bh)) | |
470decc6 DK |
1967 | mark_buffer_dirty(bh); /* Expose it to the VM */ |
1968 | } | |
1969 | ||
de1b7941 JK |
1970 | /* |
1971 | * Remove buffer from all transactions. | |
1972 | * | |
1973 | * Called with bh_state lock and j_list_lock | |
1974 | * | |
1975 | * jh and bh may be already freed when this function returns. | |
1976 | */ | |
1977 | static void __jbd2_journal_unfile_buffer(struct journal_head *jh) | |
470decc6 | 1978 | { |
f7f4bccb | 1979 | __jbd2_journal_temp_unlink_buffer(jh); |
470decc6 | 1980 | jh->b_transaction = NULL; |
de1b7941 | 1981 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
1982 | } |
1983 | ||
f7f4bccb | 1984 | void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 | 1985 | { |
de1b7941 JK |
1986 | struct buffer_head *bh = jh2bh(jh); |
1987 | ||
1988 | /* Get reference so that buffer cannot be freed before we unlock it */ | |
1989 | get_bh(bh); | |
1990 | jbd_lock_bh_state(bh); | |
470decc6 | 1991 | spin_lock(&journal->j_list_lock); |
f7f4bccb | 1992 | __jbd2_journal_unfile_buffer(jh); |
470decc6 | 1993 | spin_unlock(&journal->j_list_lock); |
de1b7941 JK |
1994 | jbd_unlock_bh_state(bh); |
1995 | __brelse(bh); | |
470decc6 DK |
1996 | } |
1997 | ||
1998 | /* | |
f7f4bccb | 1999 | * Called from jbd2_journal_try_to_free_buffers(). |
470decc6 DK |
2000 | * |
2001 | * Called under jbd_lock_bh_state(bh) | |
2002 | */ | |
2003 | static void | |
2004 | __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) | |
2005 | { | |
2006 | struct journal_head *jh; | |
2007 | ||
2008 | jh = bh2jh(bh); | |
2009 | ||
2010 | if (buffer_locked(bh) || buffer_dirty(bh)) | |
2011 | goto out; | |
2012 | ||
d2eb0b99 | 2013 | if (jh->b_next_transaction != NULL || jh->b_transaction != NULL) |
470decc6 DK |
2014 | goto out; |
2015 | ||
2016 | spin_lock(&journal->j_list_lock); | |
d2eb0b99 | 2017 | if (jh->b_cp_transaction != NULL) { |
470decc6 | 2018 | /* written-back checkpointed metadata buffer */ |
c254c9ec JK |
2019 | JBUFFER_TRACE(jh, "remove from checkpoint list"); |
2020 | __jbd2_journal_remove_checkpoint(jh); | |
470decc6 DK |
2021 | } |
2022 | spin_unlock(&journal->j_list_lock); | |
2023 | out: | |
2024 | return; | |
2025 | } | |
2026 | ||
470decc6 | 2027 | /** |
f7f4bccb | 2028 | * int jbd2_journal_try_to_free_buffers() - try to free page buffers. |
470decc6 DK |
2029 | * @journal: journal for operation |
2030 | * @page: to try and free | |
530576bb | 2031 | * @gfp_mask: we use the mask to detect how hard should we try to release |
d0164adc MG |
2032 | * buffers. If __GFP_DIRECT_RECLAIM and __GFP_FS is set, we wait for commit |
2033 | * code to release the buffers. | |
470decc6 DK |
2034 | * |
2035 | * | |
2036 | * For all the buffers on this page, | |
2037 | * if they are fully written out ordered data, move them onto BUF_CLEAN | |
2038 | * so try_to_free_buffers() can reap them. | |
2039 | * | |
2040 | * This function returns non-zero if we wish try_to_free_buffers() | |
2041 | * to be called. We do this if the page is releasable by try_to_free_buffers(). | |
2042 | * We also do it if the page has locked or dirty buffers and the caller wants | |
2043 | * us to perform sync or async writeout. | |
2044 | * | |
2045 | * This complicates JBD locking somewhat. We aren't protected by the | |
2046 | * BKL here. We wish to remove the buffer from its committing or | |
f7f4bccb | 2047 | * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
470decc6 DK |
2048 | * |
2049 | * This may *change* the value of transaction_t->t_datalist, so anyone | |
2050 | * who looks at t_datalist needs to lock against this function. | |
2051 | * | |
f7f4bccb MC |
2052 | * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
2053 | * buffer. So we need to lock against that. jbd2_journal_dirty_data() | |
470decc6 DK |
2054 | * will come out of the lock with the buffer dirty, which makes it |
2055 | * ineligible for release here. | |
2056 | * | |
2057 | * Who else is affected by this? hmm... Really the only contender | |
2058 | * is do_get_write_access() - it could be looking at the buffer while | |
2059 | * journal_try_to_free_buffer() is changing its state. But that | |
2060 | * cannot happen because we never reallocate freed data as metadata | |
2061 | * while the data is part of a transaction. Yes? | |
530576bb MC |
2062 | * |
2063 | * Return 0 on failure, 1 on success | |
470decc6 | 2064 | */ |
f7f4bccb | 2065 | int jbd2_journal_try_to_free_buffers(journal_t *journal, |
530576bb | 2066 | struct page *page, gfp_t gfp_mask) |
470decc6 DK |
2067 | { |
2068 | struct buffer_head *head; | |
2069 | struct buffer_head *bh; | |
2070 | int ret = 0; | |
2071 | ||
2072 | J_ASSERT(PageLocked(page)); | |
2073 | ||
2074 | head = page_buffers(page); | |
2075 | bh = head; | |
2076 | do { | |
2077 | struct journal_head *jh; | |
2078 | ||
2079 | /* | |
2080 | * We take our own ref against the journal_head here to avoid | |
2081 | * having to add tons of locking around each instance of | |
530576bb | 2082 | * jbd2_journal_put_journal_head(). |
470decc6 | 2083 | */ |
f7f4bccb | 2084 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
2085 | if (!jh) |
2086 | continue; | |
2087 | ||
2088 | jbd_lock_bh_state(bh); | |
2089 | __journal_try_to_free_buffer(journal, bh); | |
f7f4bccb | 2090 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2091 | jbd_unlock_bh_state(bh); |
2092 | if (buffer_jbd(bh)) | |
2093 | goto busy; | |
2094 | } while ((bh = bh->b_this_page) != head); | |
530576bb | 2095 | |
470decc6 | 2096 | ret = try_to_free_buffers(page); |
530576bb | 2097 | |
470decc6 DK |
2098 | busy: |
2099 | return ret; | |
2100 | } | |
2101 | ||
2102 | /* | |
2103 | * This buffer is no longer needed. If it is on an older transaction's | |
2104 | * checkpoint list we need to record it on this transaction's forget list | |
2105 | * to pin this buffer (and hence its checkpointing transaction) down until | |
2106 | * this transaction commits. If the buffer isn't on a checkpoint list, we | |
2107 | * release it. | |
2108 | * Returns non-zero if JBD no longer has an interest in the buffer. | |
2109 | * | |
2110 | * Called under j_list_lock. | |
2111 | * | |
2112 | * Called under jbd_lock_bh_state(bh). | |
2113 | */ | |
2114 | static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) | |
2115 | { | |
2116 | int may_free = 1; | |
2117 | struct buffer_head *bh = jh2bh(jh); | |
2118 | ||
470decc6 DK |
2119 | if (jh->b_cp_transaction) { |
2120 | JBUFFER_TRACE(jh, "on running+cp transaction"); | |
de1b7941 | 2121 | __jbd2_journal_temp_unlink_buffer(jh); |
f91d1d04 JK |
2122 | /* |
2123 | * We don't want to write the buffer anymore, clear the | |
2124 | * bit so that we don't confuse checks in | |
2125 | * __journal_file_buffer | |
2126 | */ | |
2127 | clear_buffer_dirty(bh); | |
f7f4bccb | 2128 | __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
470decc6 DK |
2129 | may_free = 0; |
2130 | } else { | |
2131 | JBUFFER_TRACE(jh, "on running transaction"); | |
de1b7941 | 2132 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
2133 | } |
2134 | return may_free; | |
2135 | } | |
2136 | ||
2137 | /* | |
f7f4bccb | 2138 | * jbd2_journal_invalidatepage |
470decc6 DK |
2139 | * |
2140 | * This code is tricky. It has a number of cases to deal with. | |
2141 | * | |
2142 | * There are two invariants which this code relies on: | |
2143 | * | |
2144 | * i_size must be updated on disk before we start calling invalidatepage on the | |
2145 | * data. | |
2146 | * | |
2147 | * This is done in ext3 by defining an ext3_setattr method which | |
2148 | * updates i_size before truncate gets going. By maintaining this | |
2149 | * invariant, we can be sure that it is safe to throw away any buffers | |
2150 | * attached to the current transaction: once the transaction commits, | |
2151 | * we know that the data will not be needed. | |
2152 | * | |
2153 | * Note however that we can *not* throw away data belonging to the | |
2154 | * previous, committing transaction! | |
2155 | * | |
2156 | * Any disk blocks which *are* part of the previous, committing | |
2157 | * transaction (and which therefore cannot be discarded immediately) are | |
2158 | * not going to be reused in the new running transaction | |
2159 | * | |
2160 | * The bitmap committed_data images guarantee this: any block which is | |
2161 | * allocated in one transaction and removed in the next will be marked | |
2162 | * as in-use in the committed_data bitmap, so cannot be reused until | |
2163 | * the next transaction to delete the block commits. This means that | |
2164 | * leaving committing buffers dirty is quite safe: the disk blocks | |
2165 | * cannot be reallocated to a different file and so buffer aliasing is | |
2166 | * not possible. | |
2167 | * | |
2168 | * | |
2169 | * The above applies mainly to ordered data mode. In writeback mode we | |
2170 | * don't make guarantees about the order in which data hits disk --- in | |
2171 | * particular we don't guarantee that new dirty data is flushed before | |
2172 | * transaction commit --- so it is always safe just to discard data | |
2173 | * immediately in that mode. --sct | |
2174 | */ | |
2175 | ||
2176 | /* | |
2177 | * The journal_unmap_buffer helper function returns zero if the buffer | |
2178 | * concerned remains pinned as an anonymous buffer belonging to an older | |
2179 | * transaction. | |
2180 | * | |
2181 | * We're outside-transaction here. Either or both of j_running_transaction | |
2182 | * and j_committing_transaction may be NULL. | |
2183 | */ | |
b794e7a6 JK |
2184 | static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, |
2185 | int partial_page) | |
470decc6 DK |
2186 | { |
2187 | transaction_t *transaction; | |
2188 | struct journal_head *jh; | |
2189 | int may_free = 1; | |
470decc6 DK |
2190 | |
2191 | BUFFER_TRACE(bh, "entry"); | |
2192 | ||
2193 | /* | |
2194 | * It is safe to proceed here without the j_list_lock because the | |
2195 | * buffers cannot be stolen by try_to_free_buffers as long as we are | |
2196 | * holding the page lock. --sct | |
2197 | */ | |
2198 | ||
2199 | if (!buffer_jbd(bh)) | |
2200 | goto zap_buffer_unlocked; | |
2201 | ||
87c89c23 | 2202 | /* OK, we have data buffer in journaled mode */ |
a931da6a | 2203 | write_lock(&journal->j_state_lock); |
470decc6 DK |
2204 | jbd_lock_bh_state(bh); |
2205 | spin_lock(&journal->j_list_lock); | |
2206 | ||
f7f4bccb | 2207 | jh = jbd2_journal_grab_journal_head(bh); |
470decc6 DK |
2208 | if (!jh) |
2209 | goto zap_buffer_no_jh; | |
2210 | ||
ba869023 | 2211 | /* |
2212 | * We cannot remove the buffer from checkpoint lists until the | |
2213 | * transaction adding inode to orphan list (let's call it T) | |
2214 | * is committed. Otherwise if the transaction changing the | |
2215 | * buffer would be cleaned from the journal before T is | |
2216 | * committed, a crash will cause that the correct contents of | |
2217 | * the buffer will be lost. On the other hand we have to | |
2218 | * clear the buffer dirty bit at latest at the moment when the | |
2219 | * transaction marking the buffer as freed in the filesystem | |
2220 | * structures is committed because from that moment on the | |
b794e7a6 | 2221 | * block can be reallocated and used by a different page. |
ba869023 | 2222 | * Since the block hasn't been freed yet but the inode has |
2223 | * already been added to orphan list, it is safe for us to add | |
2224 | * the buffer to BJ_Forget list of the newest transaction. | |
b794e7a6 JK |
2225 | * |
2226 | * Also we have to clear buffer_mapped flag of a truncated buffer | |
2227 | * because the buffer_head may be attached to the page straddling | |
2228 | * i_size (can happen only when blocksize < pagesize) and thus the | |
2229 | * buffer_head can be reused when the file is extended again. So we end | |
2230 | * up keeping around invalidated buffers attached to transactions' | |
2231 | * BJ_Forget list just to stop checkpointing code from cleaning up | |
2232 | * the transaction this buffer was modified in. | |
ba869023 | 2233 | */ |
470decc6 DK |
2234 | transaction = jh->b_transaction; |
2235 | if (transaction == NULL) { | |
2236 | /* First case: not on any transaction. If it | |
2237 | * has no checkpoint link, then we can zap it: | |
2238 | * it's a writeback-mode buffer so we don't care | |
2239 | * if it hits disk safely. */ | |
2240 | if (!jh->b_cp_transaction) { | |
2241 | JBUFFER_TRACE(jh, "not on any transaction: zap"); | |
2242 | goto zap_buffer; | |
2243 | } | |
2244 | ||
2245 | if (!buffer_dirty(bh)) { | |
2246 | /* bdflush has written it. We can drop it now */ | |
bc23f0c8 | 2247 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
2248 | goto zap_buffer; |
2249 | } | |
2250 | ||
2251 | /* OK, it must be in the journal but still not | |
2252 | * written fully to disk: it's metadata or | |
2253 | * journaled data... */ | |
2254 | ||
2255 | if (journal->j_running_transaction) { | |
2256 | /* ... and once the current transaction has | |
2257 | * committed, the buffer won't be needed any | |
2258 | * longer. */ | |
2259 | JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); | |
b794e7a6 | 2260 | may_free = __dispose_buffer(jh, |
470decc6 | 2261 | journal->j_running_transaction); |
b794e7a6 | 2262 | goto zap_buffer; |
470decc6 DK |
2263 | } else { |
2264 | /* There is no currently-running transaction. So the | |
2265 | * orphan record which we wrote for this file must have | |
2266 | * passed into commit. We must attach this buffer to | |
2267 | * the committing transaction, if it exists. */ | |
2268 | if (journal->j_committing_transaction) { | |
2269 | JBUFFER_TRACE(jh, "give to committing trans"); | |
b794e7a6 | 2270 | may_free = __dispose_buffer(jh, |
470decc6 | 2271 | journal->j_committing_transaction); |
b794e7a6 | 2272 | goto zap_buffer; |
470decc6 DK |
2273 | } else { |
2274 | /* The orphan record's transaction has | |
2275 | * committed. We can cleanse this buffer */ | |
2276 | clear_buffer_jbddirty(bh); | |
bc23f0c8 | 2277 | __jbd2_journal_remove_checkpoint(jh); |
470decc6 DK |
2278 | goto zap_buffer; |
2279 | } | |
2280 | } | |
2281 | } else if (transaction == journal->j_committing_transaction) { | |
9b57988d | 2282 | JBUFFER_TRACE(jh, "on committing transaction"); |
470decc6 | 2283 | /* |
ba869023 | 2284 | * The buffer is committing, we simply cannot touch |
b794e7a6 JK |
2285 | * it. If the page is straddling i_size we have to wait |
2286 | * for commit and try again. | |
2287 | */ | |
2288 | if (partial_page) { | |
b794e7a6 JK |
2289 | jbd2_journal_put_journal_head(jh); |
2290 | spin_unlock(&journal->j_list_lock); | |
2291 | jbd_unlock_bh_state(bh); | |
2292 | write_unlock(&journal->j_state_lock); | |
53e87268 | 2293 | return -EBUSY; |
b794e7a6 JK |
2294 | } |
2295 | /* | |
2296 | * OK, buffer won't be reachable after truncate. We just set | |
2297 | * j_next_transaction to the running transaction (if there is | |
2298 | * one) and mark buffer as freed so that commit code knows it | |
2299 | * should clear dirty bits when it is done with the buffer. | |
ba869023 | 2300 | */ |
470decc6 | 2301 | set_buffer_freed(bh); |
ba869023 | 2302 | if (journal->j_running_transaction && buffer_jbddirty(bh)) |
2303 | jh->b_next_transaction = journal->j_running_transaction; | |
f7f4bccb | 2304 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2305 | spin_unlock(&journal->j_list_lock); |
2306 | jbd_unlock_bh_state(bh); | |
a931da6a | 2307 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
2308 | return 0; |
2309 | } else { | |
2310 | /* Good, the buffer belongs to the running transaction. | |
2311 | * We are writing our own transaction's data, not any | |
2312 | * previous one's, so it is safe to throw it away | |
2313 | * (remember that we expect the filesystem to have set | |
2314 | * i_size already for this truncate so recovery will not | |
2315 | * expose the disk blocks we are discarding here.) */ | |
2316 | J_ASSERT_JH(jh, transaction == journal->j_running_transaction); | |
9b57988d | 2317 | JBUFFER_TRACE(jh, "on running transaction"); |
470decc6 DK |
2318 | may_free = __dispose_buffer(jh, transaction); |
2319 | } | |
2320 | ||
2321 | zap_buffer: | |
b794e7a6 JK |
2322 | /* |
2323 | * This is tricky. Although the buffer is truncated, it may be reused | |
2324 | * if blocksize < pagesize and it is attached to the page straddling | |
2325 | * EOF. Since the buffer might have been added to BJ_Forget list of the | |
2326 | * running transaction, journal_get_write_access() won't clear | |
2327 | * b_modified and credit accounting gets confused. So clear b_modified | |
2328 | * here. | |
2329 | */ | |
2330 | jh->b_modified = 0; | |
f7f4bccb | 2331 | jbd2_journal_put_journal_head(jh); |
470decc6 DK |
2332 | zap_buffer_no_jh: |
2333 | spin_unlock(&journal->j_list_lock); | |
2334 | jbd_unlock_bh_state(bh); | |
a931da6a | 2335 | write_unlock(&journal->j_state_lock); |
470decc6 DK |
2336 | zap_buffer_unlocked: |
2337 | clear_buffer_dirty(bh); | |
2338 | J_ASSERT_BH(bh, !buffer_jbddirty(bh)); | |
2339 | clear_buffer_mapped(bh); | |
2340 | clear_buffer_req(bh); | |
2341 | clear_buffer_new(bh); | |
15291164 ES |
2342 | clear_buffer_delay(bh); |
2343 | clear_buffer_unwritten(bh); | |
470decc6 DK |
2344 | bh->b_bdev = NULL; |
2345 | return may_free; | |
2346 | } | |
2347 | ||
2348 | /** | |
f7f4bccb | 2349 | * void jbd2_journal_invalidatepage() |
470decc6 DK |
2350 | * @journal: journal to use for flush... |
2351 | * @page: page to flush | |
259709b0 LC |
2352 | * @offset: start of the range to invalidate |
2353 | * @length: length of the range to invalidate | |
470decc6 | 2354 | * |
259709b0 LC |
2355 | * Reap page buffers containing data after in the specified range in page. |
2356 | * Can return -EBUSY if buffers are part of the committing transaction and | |
2357 | * the page is straddling i_size. Caller then has to wait for current commit | |
2358 | * and try again. | |
470decc6 | 2359 | */ |
53e87268 JK |
2360 | int jbd2_journal_invalidatepage(journal_t *journal, |
2361 | struct page *page, | |
259709b0 LC |
2362 | unsigned int offset, |
2363 | unsigned int length) | |
470decc6 DK |
2364 | { |
2365 | struct buffer_head *head, *bh, *next; | |
259709b0 | 2366 | unsigned int stop = offset + length; |
470decc6 | 2367 | unsigned int curr_off = 0; |
09cbfeaf | 2368 | int partial_page = (offset || length < PAGE_SIZE); |
470decc6 | 2369 | int may_free = 1; |
53e87268 | 2370 | int ret = 0; |
470decc6 DK |
2371 | |
2372 | if (!PageLocked(page)) | |
2373 | BUG(); | |
2374 | if (!page_has_buffers(page)) | |
53e87268 | 2375 | return 0; |
470decc6 | 2376 | |
09cbfeaf | 2377 | BUG_ON(stop > PAGE_SIZE || stop < length); |
259709b0 | 2378 | |
470decc6 DK |
2379 | /* We will potentially be playing with lists other than just the |
2380 | * data lists (especially for journaled data mode), so be | |
2381 | * cautious in our locking. */ | |
2382 | ||
2383 | head = bh = page_buffers(page); | |
2384 | do { | |
2385 | unsigned int next_off = curr_off + bh->b_size; | |
2386 | next = bh->b_this_page; | |
2387 | ||
259709b0 LC |
2388 | if (next_off > stop) |
2389 | return 0; | |
2390 | ||
470decc6 DK |
2391 | if (offset <= curr_off) { |
2392 | /* This block is wholly outside the truncation point */ | |
2393 | lock_buffer(bh); | |
259709b0 | 2394 | ret = journal_unmap_buffer(journal, bh, partial_page); |
470decc6 | 2395 | unlock_buffer(bh); |
53e87268 JK |
2396 | if (ret < 0) |
2397 | return ret; | |
2398 | may_free &= ret; | |
470decc6 DK |
2399 | } |
2400 | curr_off = next_off; | |
2401 | bh = next; | |
2402 | ||
2403 | } while (bh != head); | |
2404 | ||
259709b0 | 2405 | if (!partial_page) { |
470decc6 DK |
2406 | if (may_free && try_to_free_buffers(page)) |
2407 | J_ASSERT(!page_has_buffers(page)); | |
2408 | } | |
53e87268 | 2409 | return 0; |
470decc6 DK |
2410 | } |
2411 | ||
2412 | /* | |
2413 | * File a buffer on the given transaction list. | |
2414 | */ | |
f7f4bccb | 2415 | void __jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2416 | transaction_t *transaction, int jlist) |
2417 | { | |
2418 | struct journal_head **list = NULL; | |
2419 | int was_dirty = 0; | |
2420 | struct buffer_head *bh = jh2bh(jh); | |
2421 | ||
2422 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
2423 | assert_spin_locked(&transaction->t_journal->j_list_lock); | |
2424 | ||
2425 | J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); | |
2426 | J_ASSERT_JH(jh, jh->b_transaction == transaction || | |
4019191b | 2427 | jh->b_transaction == NULL); |
470decc6 DK |
2428 | |
2429 | if (jh->b_transaction && jh->b_jlist == jlist) | |
2430 | return; | |
2431 | ||
470decc6 DK |
2432 | if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
2433 | jlist == BJ_Shadow || jlist == BJ_Forget) { | |
f91d1d04 JK |
2434 | /* |
2435 | * For metadata buffers, we track dirty bit in buffer_jbddirty | |
2436 | * instead of buffer_dirty. We should not see a dirty bit set | |
2437 | * here because we clear it in do_get_write_access but e.g. | |
2438 | * tune2fs can modify the sb and set the dirty bit at any time | |
2439 | * so we try to gracefully handle that. | |
2440 | */ | |
2441 | if (buffer_dirty(bh)) | |
2442 | warn_dirty_buffer(bh); | |
470decc6 DK |
2443 | if (test_clear_buffer_dirty(bh) || |
2444 | test_clear_buffer_jbddirty(bh)) | |
2445 | was_dirty = 1; | |
2446 | } | |
2447 | ||
2448 | if (jh->b_transaction) | |
f7f4bccb | 2449 | __jbd2_journal_temp_unlink_buffer(jh); |
de1b7941 JK |
2450 | else |
2451 | jbd2_journal_grab_journal_head(bh); | |
470decc6 DK |
2452 | jh->b_transaction = transaction; |
2453 | ||
2454 | switch (jlist) { | |
2455 | case BJ_None: | |
2456 | J_ASSERT_JH(jh, !jh->b_committed_data); | |
2457 | J_ASSERT_JH(jh, !jh->b_frozen_data); | |
2458 | return; | |
470decc6 DK |
2459 | case BJ_Metadata: |
2460 | transaction->t_nr_buffers++; | |
2461 | list = &transaction->t_buffers; | |
2462 | break; | |
2463 | case BJ_Forget: | |
2464 | list = &transaction->t_forget; | |
2465 | break; | |
470decc6 DK |
2466 | case BJ_Shadow: |
2467 | list = &transaction->t_shadow_list; | |
2468 | break; | |
470decc6 DK |
2469 | case BJ_Reserved: |
2470 | list = &transaction->t_reserved_list; | |
2471 | break; | |
470decc6 DK |
2472 | } |
2473 | ||
2474 | __blist_add_buffer(list, jh); | |
2475 | jh->b_jlist = jlist; | |
2476 | ||
2477 | if (was_dirty) | |
2478 | set_buffer_jbddirty(bh); | |
2479 | } | |
2480 | ||
f7f4bccb | 2481 | void jbd2_journal_file_buffer(struct journal_head *jh, |
470decc6 DK |
2482 | transaction_t *transaction, int jlist) |
2483 | { | |
2484 | jbd_lock_bh_state(jh2bh(jh)); | |
2485 | spin_lock(&transaction->t_journal->j_list_lock); | |
f7f4bccb | 2486 | __jbd2_journal_file_buffer(jh, transaction, jlist); |
470decc6 DK |
2487 | spin_unlock(&transaction->t_journal->j_list_lock); |
2488 | jbd_unlock_bh_state(jh2bh(jh)); | |
2489 | } | |
2490 | ||
2491 | /* | |
2492 | * Remove a buffer from its current buffer list in preparation for | |
2493 | * dropping it from its current transaction entirely. If the buffer has | |
2494 | * already started to be used by a subsequent transaction, refile the | |
2495 | * buffer on that transaction's metadata list. | |
2496 | * | |
de1b7941 | 2497 | * Called under j_list_lock |
470decc6 | 2498 | * Called under jbd_lock_bh_state(jh2bh(jh)) |
de1b7941 JK |
2499 | * |
2500 | * jh and bh may be already free when this function returns | |
470decc6 | 2501 | */ |
f7f4bccb | 2502 | void __jbd2_journal_refile_buffer(struct journal_head *jh) |
470decc6 | 2503 | { |
ba869023 | 2504 | int was_dirty, jlist; |
470decc6 DK |
2505 | struct buffer_head *bh = jh2bh(jh); |
2506 | ||
2507 | J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); | |
2508 | if (jh->b_transaction) | |
2509 | assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); | |
2510 | ||
2511 | /* If the buffer is now unused, just drop it. */ | |
2512 | if (jh->b_next_transaction == NULL) { | |
f7f4bccb | 2513 | __jbd2_journal_unfile_buffer(jh); |
470decc6 DK |
2514 | return; |
2515 | } | |
2516 | ||
2517 | /* | |
2518 | * It has been modified by a later transaction: add it to the new | |
2519 | * transaction's metadata list. | |
2520 | */ | |
2521 | ||
2522 | was_dirty = test_clear_buffer_jbddirty(bh); | |
f7f4bccb | 2523 | __jbd2_journal_temp_unlink_buffer(jh); |
de1b7941 JK |
2524 | /* |
2525 | * We set b_transaction here because b_next_transaction will inherit | |
2526 | * our jh reference and thus __jbd2_journal_file_buffer() must not | |
2527 | * take a new one. | |
2528 | */ | |
470decc6 DK |
2529 | jh->b_transaction = jh->b_next_transaction; |
2530 | jh->b_next_transaction = NULL; | |
ba869023 | 2531 | if (buffer_freed(bh)) |
2532 | jlist = BJ_Forget; | |
2533 | else if (jh->b_modified) | |
2534 | jlist = BJ_Metadata; | |
2535 | else | |
2536 | jlist = BJ_Reserved; | |
2537 | __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist); | |
470decc6 DK |
2538 | J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
2539 | ||
2540 | if (was_dirty) | |
2541 | set_buffer_jbddirty(bh); | |
2542 | } | |
2543 | ||
2544 | /* | |
de1b7941 JK |
2545 | * __jbd2_journal_refile_buffer() with necessary locking added. We take our |
2546 | * bh reference so that we can safely unlock bh. | |
2547 | * | |
2548 | * The jh and bh may be freed by this call. | |
470decc6 | 2549 | */ |
f7f4bccb | 2550 | void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
470decc6 DK |
2551 | { |
2552 | struct buffer_head *bh = jh2bh(jh); | |
2553 | ||
de1b7941 JK |
2554 | /* Get reference so that buffer cannot be freed before we unlock it */ |
2555 | get_bh(bh); | |
470decc6 DK |
2556 | jbd_lock_bh_state(bh); |
2557 | spin_lock(&journal->j_list_lock); | |
f7f4bccb | 2558 | __jbd2_journal_refile_buffer(jh); |
470decc6 | 2559 | jbd_unlock_bh_state(bh); |
470decc6 DK |
2560 | spin_unlock(&journal->j_list_lock); |
2561 | __brelse(bh); | |
2562 | } | |
c851ed54 JK |
2563 | |
2564 | /* | |
2565 | * File inode in the inode list of the handle's transaction | |
2566 | */ | |
41617e1a JK |
2567 | static int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode, |
2568 | unsigned long flags) | |
c851ed54 JK |
2569 | { |
2570 | transaction_t *transaction = handle->h_transaction; | |
41a5b913 | 2571 | journal_t *journal; |
c851ed54 JK |
2572 | |
2573 | if (is_handle_aborted(handle)) | |
41a5b913 TT |
2574 | return -EROFS; |
2575 | journal = transaction->t_journal; | |
c851ed54 JK |
2576 | |
2577 | jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, | |
2578 | transaction->t_tid); | |
2579 | ||
2580 | /* | |
2581 | * First check whether inode isn't already on the transaction's | |
2582 | * lists without taking the lock. Note that this check is safe | |
2583 | * without the lock as we cannot race with somebody removing inode | |
2584 | * from the transaction. The reason is that we remove inode from the | |
2585 | * transaction only in journal_release_jbd_inode() and when we commit | |
2586 | * the transaction. We are guarded from the first case by holding | |
2587 | * a reference to the inode. We are safe against the second case | |
2588 | * because if jinode->i_transaction == transaction, commit code | |
2589 | * cannot touch the transaction because we hold reference to it, | |
2590 | * and if jinode->i_next_transaction == transaction, commit code | |
2591 | * will only file the inode where we want it. | |
2592 | */ | |
41617e1a JK |
2593 | if ((jinode->i_transaction == transaction || |
2594 | jinode->i_next_transaction == transaction) && | |
2595 | (jinode->i_flags & flags) == flags) | |
c851ed54 JK |
2596 | return 0; |
2597 | ||
2598 | spin_lock(&journal->j_list_lock); | |
41617e1a JK |
2599 | jinode->i_flags |= flags; |
2600 | /* Is inode already attached where we need it? */ | |
c851ed54 JK |
2601 | if (jinode->i_transaction == transaction || |
2602 | jinode->i_next_transaction == transaction) | |
2603 | goto done; | |
2604 | ||
81be12c8 JK |
2605 | /* |
2606 | * We only ever set this variable to 1 so the test is safe. Since | |
2607 | * t_need_data_flush is likely to be set, we do the test to save some | |
2608 | * cacheline bouncing | |
2609 | */ | |
2610 | if (!transaction->t_need_data_flush) | |
2611 | transaction->t_need_data_flush = 1; | |
c851ed54 JK |
2612 | /* On some different transaction's list - should be |
2613 | * the committing one */ | |
2614 | if (jinode->i_transaction) { | |
2615 | J_ASSERT(jinode->i_next_transaction == NULL); | |
2616 | J_ASSERT(jinode->i_transaction == | |
2617 | journal->j_committing_transaction); | |
2618 | jinode->i_next_transaction = transaction; | |
2619 | goto done; | |
2620 | } | |
2621 | /* Not on any transaction list... */ | |
2622 | J_ASSERT(!jinode->i_next_transaction); | |
2623 | jinode->i_transaction = transaction; | |
2624 | list_add(&jinode->i_list, &transaction->t_inode_list); | |
2625 | done: | |
2626 | spin_unlock(&journal->j_list_lock); | |
2627 | ||
2628 | return 0; | |
2629 | } | |
2630 | ||
41617e1a JK |
2631 | int jbd2_journal_inode_add_write(handle_t *handle, struct jbd2_inode *jinode) |
2632 | { | |
2633 | return jbd2_journal_file_inode(handle, jinode, | |
2634 | JI_WRITE_DATA | JI_WAIT_DATA); | |
2635 | } | |
2636 | ||
2637 | int jbd2_journal_inode_add_wait(handle_t *handle, struct jbd2_inode *jinode) | |
2638 | { | |
2639 | return jbd2_journal_file_inode(handle, jinode, JI_WAIT_DATA); | |
2640 | } | |
2641 | ||
c851ed54 | 2642 | /* |
7f5aa215 JK |
2643 | * File truncate and transaction commit interact with each other in a |
2644 | * non-trivial way. If a transaction writing data block A is | |
2645 | * committing, we cannot discard the data by truncate until we have | |
2646 | * written them. Otherwise if we crashed after the transaction with | |
2647 | * write has committed but before the transaction with truncate has | |
2648 | * committed, we could see stale data in block A. This function is a | |
2649 | * helper to solve this problem. It starts writeout of the truncated | |
2650 | * part in case it is in the committing transaction. | |
2651 | * | |
2652 | * Filesystem code must call this function when inode is journaled in | |
2653 | * ordered mode before truncation happens and after the inode has been | |
2654 | * placed on orphan list with the new inode size. The second condition | |
2655 | * avoids the race that someone writes new data and we start | |
2656 | * committing the transaction after this function has been called but | |
2657 | * before a transaction for truncate is started (and furthermore it | |
2658 | * allows us to optimize the case where the addition to orphan list | |
2659 | * happens in the same transaction as write --- we don't have to write | |
2660 | * any data in such case). | |
c851ed54 | 2661 | */ |
7f5aa215 JK |
2662 | int jbd2_journal_begin_ordered_truncate(journal_t *journal, |
2663 | struct jbd2_inode *jinode, | |
c851ed54 JK |
2664 | loff_t new_size) |
2665 | { | |
7f5aa215 | 2666 | transaction_t *inode_trans, *commit_trans; |
c851ed54 JK |
2667 | int ret = 0; |
2668 | ||
7f5aa215 JK |
2669 | /* This is a quick check to avoid locking if not necessary */ |
2670 | if (!jinode->i_transaction) | |
c851ed54 | 2671 | goto out; |
7f5aa215 JK |
2672 | /* Locks are here just to force reading of recent values, it is |
2673 | * enough that the transaction was not committing before we started | |
2674 | * a transaction adding the inode to orphan list */ | |
a931da6a | 2675 | read_lock(&journal->j_state_lock); |
c851ed54 | 2676 | commit_trans = journal->j_committing_transaction; |
a931da6a | 2677 | read_unlock(&journal->j_state_lock); |
7f5aa215 JK |
2678 | spin_lock(&journal->j_list_lock); |
2679 | inode_trans = jinode->i_transaction; | |
2680 | spin_unlock(&journal->j_list_lock); | |
2681 | if (inode_trans == commit_trans) { | |
2682 | ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping, | |
c851ed54 JK |
2683 | new_size, LLONG_MAX); |
2684 | if (ret) | |
2685 | jbd2_journal_abort(journal, ret); | |
2686 | } | |
2687 | out: | |
2688 | return ret; | |
2689 | } |