Branch data Line data Source code
1 : : /*
2 : : * linux/fs/jbd2/transaction.c
3 : : *
4 : : * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 : : *
6 : : * Copyright 1998 Red Hat corp --- All Rights Reserved
7 : : *
8 : : * This file is part of the Linux kernel and is made available under
9 : : * the terms of the GNU General Public License, version 2, or at your
10 : : * option, any later version, incorporated herein by reference.
11 : : *
12 : : * Generic filesystem transaction handling code; part of the ext2fs
13 : : * journaling system.
14 : : *
15 : : * This file manages transactions (compound commits managed by the
16 : : * journaling code) and handles (individual atomic operations by the
17 : : * filesystem).
18 : : */
19 : :
20 : : #include <linux/time.h>
21 : : #include <linux/fs.h>
22 : : #include <linux/jbd2.h>
23 : : #include <linux/errno.h>
24 : : #include <linux/slab.h>
25 : : #include <linux/timer.h>
26 : : #include <linux/mm.h>
27 : : #include <linux/highmem.h>
28 : : #include <linux/hrtimer.h>
29 : : #include <linux/backing-dev.h>
30 : : #include <linux/bug.h>
31 : : #include <linux/module.h>
32 : :
33 : : #include <trace/events/jbd2.h>
34 : :
35 : : static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
36 : : static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
37 : :
38 : : static struct kmem_cache *transaction_cache;
39 : 0 : int __init jbd2_journal_init_transaction_cache(void)
40 : : {
41 [ # # ]: 0 : J_ASSERT(!transaction_cache);
42 : 0 : transaction_cache = kmem_cache_create("jbd2_transaction_s",
43 : : sizeof(transaction_t),
44 : : 0,
45 : : SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
46 : : NULL);
47 [ # # ]: 0 : if (transaction_cache)
48 : : return 0;
49 : 0 : return -ENOMEM;
50 : : }
51 : :
52 : 0 : void jbd2_journal_destroy_transaction_cache(void)
53 : : {
54 [ # # ]: 0 : if (transaction_cache) {
55 : 0 : kmem_cache_destroy(transaction_cache);
56 : 0 : transaction_cache = NULL;
57 : : }
58 : 0 : }
59 : :
60 : 0 : void jbd2_journal_free_transaction(transaction_t *transaction)
61 : : {
62 [ # # + + ]: 8351406 : if (unlikely(ZERO_OR_NULL_PTR(transaction)))
[ + - ]
63 : 0 : return;
64 : 20126 : kmem_cache_free(transaction_cache, transaction);
65 : : }
66 : :
67 : : /*
68 : : * jbd2_get_transaction: obtain a new transaction_t object.
69 : : *
70 : : * Simply allocate and initialise a new transaction. Create it in
71 : : * RUNNING state and add it to the current journal (which should not
72 : : * have an existing running transaction: we only make a new transaction
73 : : * once we have started to commit the old one).
74 : : *
75 : : * Preconditions:
76 : : * The journal MUST be locked. We don't perform atomic mallocs on the
77 : : * new transaction and we can't block without protecting against other
78 : : * processes trying to touch the journal while it is in transition.
79 : : *
80 : : */
81 : :
82 : : static transaction_t *
83 : 0 : jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
84 : : {
85 : 19056 : transaction->t_journal = journal;
86 : 19056 : transaction->t_state = T_RUNNING;
87 : 19056 : transaction->t_start_time = ktime_get();
88 : 19056 : transaction->t_tid = journal->j_transaction_sequence++;
89 : 19056 : transaction->t_expires = jiffies + journal->j_commit_interval;
90 : 19056 : spin_lock_init(&transaction->t_handle_lock);
91 : 19056 : atomic_set(&transaction->t_updates, 0);
92 : 19056 : atomic_set(&transaction->t_outstanding_credits,
93 : : atomic_read(&journal->j_reserved_credits));
94 : 19056 : atomic_set(&transaction->t_handle_count, 0);
95 : 19056 : INIT_LIST_HEAD(&transaction->t_inode_list);
96 : 19056 : INIT_LIST_HEAD(&transaction->t_private_list);
97 : :
98 : : /* Set up the commit timer for the new transaction. */
99 : 19056 : journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
100 : 19056 : add_timer(&journal->j_commit_timer);
101 : :
102 [ - + ]: 19056 : J_ASSERT(journal->j_running_transaction == NULL);
103 : 19056 : journal->j_running_transaction = transaction;
104 : 19056 : transaction->t_max_wait = 0;
105 : 19056 : transaction->t_start = jiffies;
106 : 19056 : transaction->t_requested = 0;
107 : :
108 : 19056 : return transaction;
109 : : }
110 : :
111 : : /*
112 : : * Handle management.
113 : : *
114 : : * A handle_t is an object which represents a single atomic update to a
115 : : * filesystem, and which tracks all of the modifications which form part
116 : : * of that one update.
117 : : */
118 : :
119 : : /*
120 : : * Update transaction's maximum wait time, if debugging is enabled.
121 : : *
122 : : * In order for t_max_wait to be reliable, it must be protected by a
123 : : * lock. But doing so will mean that start_this_handle() can not be
124 : : * run in parallel on SMP systems, which limits our scalability. So
125 : : * unless debugging is enabled, we no longer update t_max_wait, which
126 : : * means that maximum wait time reported by the jbd2_run_stats
127 : : * tracepoint will always be zero.
128 : : */
129 : : static inline void update_t_max_wait(transaction_t *transaction,
130 : : unsigned long ts)
131 : : {
132 : : #ifdef CONFIG_JBD2_DEBUG
133 : : if (jbd2_journal_enable_debug &&
134 : : time_after(transaction->t_start, ts)) {
135 : : ts = jbd2_time_diff(ts, transaction->t_start);
136 : : spin_lock(&transaction->t_handle_lock);
137 : : if (ts > transaction->t_max_wait)
138 : : transaction->t_max_wait = ts;
139 : : spin_unlock(&transaction->t_handle_lock);
140 : : }
141 : : #endif
142 : : }
143 : :
144 : : /*
145 : : * Wait until running transaction passes T_LOCKED state. Also starts the commit
146 : : * if needed. The function expects running transaction to exist and releases
147 : : * j_state_lock.
148 : : */
149 : 0 : static void wait_transaction_locked(journal_t *journal)
150 : : __releases(journal->j_state_lock)
151 : : {
152 : 840 : DEFINE_WAIT(wait);
153 : : int need_to_start;
154 : 420 : tid_t tid = journal->j_running_transaction->t_tid;
155 : :
156 : 420 : prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
157 : : TASK_UNINTERRUPTIBLE);
158 : 420 : need_to_start = !tid_geq(journal->j_commit_request, tid);
159 : : read_unlock(&journal->j_state_lock);
160 [ - + ]: 420 : if (need_to_start)
161 : 0 : jbd2_log_start_commit(journal, tid);
162 : 420 : schedule();
163 : 419 : finish_wait(&journal->j_wait_transaction_locked, &wait);
164 : 415 : }
165 : :
166 : 0 : static void sub_reserved_credits(journal_t *journal, int blocks)
167 : : {
168 : 0 : atomic_sub(blocks, &journal->j_reserved_credits);
169 : 0 : wake_up(&journal->j_wait_reserved);
170 : 0 : }
171 : :
172 : : /*
173 : : * Wait until we can add credits for handle to the running transaction. Called
174 : : * with j_state_lock held for reading. Returns 0 if handle joined the running
175 : : * transaction. Returns 1 if we had to wait, j_state_lock is dropped, and
176 : : * caller must retry.
177 : : */
178 : 0 : static int add_transaction_credits(journal_t *journal, int blocks,
179 : : int rsv_blocks)
180 : : {
181 : 8323987 : transaction_t *t = journal->j_running_transaction;
182 : : int needed;
183 : 8323987 : int total = blocks + rsv_blocks;
184 : :
185 : : /*
186 : : * If the current transaction is locked down for commit, wait
187 : : * for the lock to be released.
188 : : */
189 [ + + ]: 8323987 : if (t->t_state == T_LOCKED) {
190 : 420 : wait_transaction_locked(journal);
191 : 418 : return 1;
192 : : }
193 : :
194 : : /*
195 : : * If there is not enough space left in the log to write all
196 : : * potential buffers requested by this operation, we need to
197 : : * stall pending a log checkpoint to free some more log space.
198 : : */
199 : 8323567 : needed = atomic_add_return(total, &t->t_outstanding_credits);
200 [ - + ]: 8324661 : if (needed > journal->j_max_transaction_buffers) {
201 : : /*
202 : : * If the current transaction is already too large,
203 : : * then start to commit it: we can then go back and
204 : : * attach this handle to a new transaction.
205 : : */
206 : : atomic_sub(total, &t->t_outstanding_credits);
207 : 0 : wait_transaction_locked(journal);
208 : 0 : return 1;
209 : : }
210 : :
211 : : /*
212 : : * The commit code assumes that it can get enough log space
213 : : * without forcing a checkpoint. This is *critical* for
214 : : * correctness: a checkpoint of a buffer which is also
215 : : * associated with a committing transaction creates a deadlock,
216 : : * so commit simply cannot force through checkpoints.
217 : : *
218 : : * We must therefore ensure the necessary space in the journal
219 : : * *before* starting to dirty potentially checkpointed buffers
220 : : * in the new transaction.
221 : : */
222 [ - + ]: 8324661 : if (jbd2_log_space_left(journal) < jbd2_space_needed(journal)) {
223 : : atomic_sub(total, &t->t_outstanding_credits);
224 : : read_unlock(&journal->j_state_lock);
225 : 0 : write_lock(&journal->j_state_lock);
226 [ # # ]: 0 : if (jbd2_log_space_left(journal) < jbd2_space_needed(journal))
227 : 0 : __jbd2_log_wait_for_space(journal);
228 : : write_unlock(&journal->j_state_lock);
229 : 0 : return 1;
230 : : }
231 : :
232 : : /* No reservation? We are done... */
233 [ - + ]: 8324661 : if (!rsv_blocks)
234 : : return 0;
235 : :
236 : 0 : needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits);
237 : : /* We allow at most half of a transaction to be reserved */
238 [ # # ]: 0 : if (needed > journal->j_max_transaction_buffers / 2) {
239 : 0 : sub_reserved_credits(journal, rsv_blocks);
240 : : atomic_sub(total, &t->t_outstanding_credits);
241 : : read_unlock(&journal->j_state_lock);
242 [ # # ][ # # ]: 0 : wait_event(journal->j_wait_reserved,
243 : : atomic_read(&journal->j_reserved_credits) + rsv_blocks
244 : : <= journal->j_max_transaction_buffers / 2);
245 : : return 1;
246 : : }
247 : : return 0;
248 : : }
249 : :
250 : : /*
251 : : * start_this_handle: Given a handle, deal with any locking or stalling
252 : : * needed to make sure that there is enough journal space for the handle
253 : : * to begin. Attach the handle to a transaction and set up the
254 : : * transaction's buffer credits.
255 : : */
256 : :
257 : 0 : static int start_this_handle(journal_t *journal, handle_t *handle,
258 : : gfp_t gfp_mask)
259 : : {
260 : : transaction_t *transaction, *new_transaction = NULL;
261 : 8330890 : int blocks = handle->h_buffer_credits;
262 : : int rsv_blocks = 0;
263 : 8330890 : unsigned long ts = jiffies;
264 : :
265 : : /*
266 : : * 1/2 of transaction can be reserved so we can practically handle
267 : : * only 1/2 of maximum transaction size per operation
268 : : */
269 [ - + ][ - + ]: 8330890 : if (WARN_ON(blocks > journal->j_max_transaction_buffers / 2)) {
270 : 0 : printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
271 : 0 : current->comm, blocks,
272 : 0 : journal->j_max_transaction_buffers / 2);
273 : 0 : return -ENOSPC;
274 : : }
275 : :
276 [ - + ]: 8329338 : if (handle->h_rsv_handle)
277 : 8329338 : rsv_blocks = handle->h_rsv_handle->h_buffer_credits;
278 : :
279 : : alloc_transaction:
280 [ + + ]: 8329753 : if (!journal->j_running_transaction) {
281 : 19278 : new_transaction = kmem_cache_zalloc(transaction_cache,
282 : : gfp_mask);
283 [ + - ]: 8330126 : if (!new_transaction) {
284 : : /*
285 : : * If __GFP_FS is not present, then we may be
286 : : * being called from inside the fs writeback
287 : : * layer, so we MUST NOT fail. Since
288 : : * __GFP_NOFAIL is going away, we will arrange
289 : : * to retry the allocation ourselves.
290 : : */
291 [ # # ]: 0 : if ((gfp_mask & __GFP_FS) == 0) {
292 : 20370 : congestion_wait(BLK_RW_ASYNC, HZ/50);
293 : 415 : goto alloc_transaction;
294 : : }
295 : : return -ENOMEM;
296 : : }
297 : : }
298 : :
299 : : jbd_debug(3, "New handle %p going live.\n", handle);
300 : :
301 : : /*
302 : : * We need to hold j_state_lock until t_updates has been incremented,
303 : : * for proper journal barrier handling
304 : : */
305 : : repeat:
306 : 8350496 : read_lock(&journal->j_state_lock);
307 [ - + ]: 8348551 : BUG_ON(journal->j_flags & JBD2_UNMOUNT);
308 [ + + ][ - + ]: 8348551 : if (is_journal_aborted(journal) ||
309 [ # # ]: 0 : (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
310 : : read_unlock(&journal->j_state_lock);
311 : : jbd2_journal_free_transaction(new_transaction);
312 : : return -EROFS;
313 : : }
314 : :
315 : : /*
316 : : * Wait on the journal's transaction barrier if necessary. Specifically
317 : : * we allow reserved handles to proceed because otherwise commit could
318 : : * deadlock on page writeback not being able to complete.
319 : : */
320 [ + ][ - + ]: 8343850 : if (!handle->h_reserved && journal->j_barrier_count) {
321 : : read_unlock(&journal->j_state_lock);
322 [ # # ][ # # ]: 0 : wait_event(journal->j_wait_transaction_locked,
323 : : journal->j_barrier_count == 0);
324 : : goto repeat;
325 : : }
326 : :
327 [ + + ]: 8343850 : if (!journal->j_running_transaction) {
328 : : read_unlock(&journal->j_state_lock);
329 [ + + ]: 20366 : if (!new_transaction)
330 : : goto alloc_transaction;
331 : 19951 : write_lock(&journal->j_state_lock);
332 [ + + ][ + - ]: 19953 : if (!journal->j_running_transaction &&
333 [ + - ]: 19056 : (handle->h_reserved || !journal->j_barrier_count)) {
334 : 19056 : jbd2_get_transaction(journal, new_transaction);
335 : : new_transaction = NULL;
336 : : }
337 : : write_unlock(&journal->j_state_lock);
338 : : goto repeat;
339 : : }
340 : :
341 : : transaction = journal->j_running_transaction;
342 : :
343 [ + - ]: 8323483 : if (!handle->h_reserved) {
344 : : /* We may have dropped j_state_lock - restart in that case */
345 [ + + ]: 8323483 : if (add_transaction_credits(journal, blocks, rsv_blocks))
346 : : goto repeat;
347 : : } else {
348 : : /*
349 : : * We have handle reserved so we are allowed to join T_LOCKED
350 : : * transaction and we don't have to check for transaction size
351 : : * and journal space.
352 : : */
353 : 0 : sub_reserved_credits(journal, blocks);
354 : 0 : handle->h_reserved = 0;
355 : : }
356 : :
357 : : /* OK, account for the buffers that this operation expects to
358 : : * use and add the handle to the running transaction.
359 : : */
360 : : update_t_max_wait(transaction, ts);
361 : 8327369 : handle->h_transaction = transaction;
362 : 8327369 : handle->h_requested_credits = blocks;
363 : 8327369 : handle->h_start_jiffies = jiffies;
364 : 8327369 : atomic_inc(&transaction->t_updates);
365 : 8326628 : atomic_inc(&transaction->t_handle_count);
366 : : jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n",
367 : : handle, blocks,
368 : : atomic_read(&transaction->t_outstanding_credits),
369 : : jbd2_log_space_left(journal));
370 : : read_unlock(&journal->j_state_lock);
371 : 8332352 : current->journal_info = handle;
372 : :
373 : : lock_map_acquire(&handle->h_lockdep_map);
374 : : jbd2_journal_free_transaction(new_transaction);
375 : : return 0;
376 : : }
377 : :
378 : : static struct lock_class_key jbd2_handle_key;
379 : :
380 : : /* Allocate a new handle. This should probably be in a slab... */
381 : 0 : static handle_t *new_handle(int nblocks)
382 : : {
383 : : handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
384 [ + ]: 8330063 : if (!handle)
385 : : return NULL;
386 : 8330239 : handle->h_buffer_credits = nblocks;
387 : 8330239 : handle->h_ref = 1;
388 : :
389 : : lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
390 : : &jbd2_handle_key, 0);
391 : :
392 : 8330239 : return handle;
393 : : }
394 : :
395 : : /**
396 : : * handle_t *jbd2_journal_start() - Obtain a new handle.
397 : : * @journal: Journal to start transaction on.
398 : : * @nblocks: number of block buffer we might modify
399 : : *
400 : : * We make sure that the transaction can guarantee at least nblocks of
401 : : * modified buffers in the log. We block until the log can guarantee
402 : : * that much space. Additionally, if rsv_blocks > 0, we also create another
403 : : * handle with rsv_blocks reserved blocks in the journal. This handle is
404 : : * is stored in h_rsv_handle. It is not attached to any particular transaction
405 : : * and thus doesn't block transaction commit. If the caller uses this reserved
406 : : * handle, it has to set h_rsv_handle to NULL as otherwise jbd2_journal_stop()
407 : : * on the parent handle will dispose the reserved one. Reserved handle has to
408 : : * be converted to a normal handle using jbd2_journal_start_reserved() before
409 : : * it can be used.
410 : : *
411 : : * Return a pointer to a newly allocated handle, or an ERR_PTR() value
412 : : * on failure.
413 : : */
414 : 0 : handle_t *jbd2__journal_start(journal_t *journal, int nblocks, int rsv_blocks,
415 : : gfp_t gfp_mask, unsigned int type,
416 : : unsigned int line_no)
417 : : {
418 : : handle_t *handle = journal_current_handle();
419 : : int err;
420 : :
421 [ + ]: 12472151 : if (!journal)
422 : : return ERR_PTR(-EROFS);
423 : :
424 [ + + ]: 12477712 : if (handle) {
425 [ - + ]: 4144553 : J_ASSERT(handle->h_transaction->t_journal == journal);
426 : 4144553 : handle->h_ref++;
427 : 4144553 : return handle;
428 : : }
429 : :
430 : 8333159 : handle = new_handle(nblocks);
431 [ + ]: 8330815 : if (!handle)
432 : : return ERR_PTR(-ENOMEM);
433 [ - + ]: 8333563 : if (rsv_blocks) {
434 : : handle_t *rsv_handle;
435 : :
436 : 0 : rsv_handle = new_handle(rsv_blocks);
437 [ # # ]: 0 : if (!rsv_handle) {
438 : : jbd2_free_handle(handle);
439 : 0 : return ERR_PTR(-ENOMEM);
440 : : }
441 : 0 : rsv_handle->h_reserved = 1;
442 : 0 : rsv_handle->h_journal = journal;
443 : 0 : handle->h_rsv_handle = rsv_handle;
444 : : }
445 : :
446 : 8333563 : err = start_this_handle(journal, handle, gfp_mask);
447 [ - + ]: 8331944 : if (err < 0) {
448 [ # # ]: 0 : if (handle->h_rsv_handle)
449 : : jbd2_free_handle(handle->h_rsv_handle);
450 : : jbd2_free_handle(handle);
451 : 0 : return ERR_PTR(err);
452 : : }
453 : 8331944 : handle->h_type = type;
454 : 8331944 : handle->h_line_no = line_no;
455 : 8331944 : trace_jbd2_handle_start(journal->j_fs_dev->bd_dev,
456 : 8331944 : handle->h_transaction->t_tid, type,
457 : : line_no, nblocks);
458 : 8331196 : return handle;
459 : : }
460 : : EXPORT_SYMBOL(jbd2__journal_start);
461 : :
462 : :
463 : 0 : handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
464 : : {
465 : 0 : return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0);
466 : : }
467 : : EXPORT_SYMBOL(jbd2_journal_start);
468 : :
469 : 0 : void jbd2_journal_free_reserved(handle_t *handle)
470 : : {
471 : 0 : journal_t *journal = handle->h_journal;
472 : :
473 [ # # ]: 0 : WARN_ON(!handle->h_reserved);
474 : 0 : sub_reserved_credits(journal, handle->h_buffer_credits);
475 : : jbd2_free_handle(handle);
476 : 0 : }
477 : : EXPORT_SYMBOL(jbd2_journal_free_reserved);
478 : :
479 : : /**
480 : : * int jbd2_journal_start_reserved(handle_t *handle) - start reserved handle
481 : : * @handle: handle to start
482 : : *
483 : : * Start handle that has been previously reserved with jbd2_journal_reserve().
484 : : * This attaches @handle to the running transaction (or creates one if there's
485 : : * not transaction running). Unlike jbd2_journal_start() this function cannot
486 : : * block on journal commit, checkpointing, or similar stuff. It can block on
487 : : * memory allocation or frozen journal though.
488 : : *
489 : : * Return 0 on success, non-zero on error - handle is freed in that case.
490 : : */
491 : 0 : int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
492 : : unsigned int line_no)
493 : : {
494 : 0 : journal_t *journal = handle->h_journal;
495 : : int ret = -EIO;
496 : :
497 [ # # ][ # # ]: 0 : if (WARN_ON(!handle->h_reserved)) {
498 : : /* Someone passed in normal handle? Just stop it. */
499 : 0 : jbd2_journal_stop(handle);
500 : 0 : return ret;
501 : : }
502 : : /*
503 : : * Usefulness of mixing of reserved and unreserved handles is
504 : : * questionable. So far nobody seems to need it so just error out.
505 : : */
506 [ # # ][ # # ]: 0 : if (WARN_ON(current->journal_info)) {
507 : 0 : jbd2_journal_free_reserved(handle);
508 : 0 : return ret;
509 : : }
510 : :
511 : 0 : handle->h_journal = NULL;
512 : : /*
513 : : * GFP_NOFS is here because callers are likely from writeback or
514 : : * similarly constrained call sites
515 : : */
516 : 0 : ret = start_this_handle(journal, handle, GFP_NOFS);
517 [ # # ]: 0 : if (ret < 0) {
518 : 0 : jbd2_journal_free_reserved(handle);
519 : 0 : return ret;
520 : : }
521 : 0 : handle->h_type = type;
522 : 0 : handle->h_line_no = line_no;
523 : 0 : return 0;
524 : : }
525 : : EXPORT_SYMBOL(jbd2_journal_start_reserved);
526 : :
527 : : /**
528 : : * int jbd2_journal_extend() - extend buffer credits.
529 : : * @handle: handle to 'extend'
530 : : * @nblocks: nr blocks to try to extend by.
531 : : *
532 : : * Some transactions, such as large extends and truncates, can be done
533 : : * atomically all at once or in several stages. The operation requests
534 : : * a credit for a number of buffer modications in advance, but can
535 : : * extend its credit if it needs more.
536 : : *
537 : : * jbd2_journal_extend tries to give the running handle more buffer credits.
538 : : * It does not guarantee that allocation - this is a best-effort only.
539 : : * The calling process MUST be able to deal cleanly with a failure to
540 : : * extend here.
541 : : *
542 : : * Return 0 on success, non-zero on failure.
543 : : *
544 : : * return code < 0 implies an error
545 : : * return code > 0 implies normal transaction-full status.
546 : : */
547 : 0 : int jbd2_journal_extend(handle_t *handle, int nblocks)
548 : : {
549 : 3225 : transaction_t *transaction = handle->h_transaction;
550 : 3212 : journal_t *journal;
551 : : int result;
552 : : int wanted;
553 : :
554 [ - + ]: 3225 : WARN_ON(!transaction);
555 [ + - ]: 3225 : if (is_handle_aborted(handle))
556 : : return -EROFS;
557 : 3225 : journal = transaction->t_journal;
558 : :
559 : : result = 1;
560 : :
561 : 3225 : read_lock(&journal->j_state_lock);
562 : :
563 : : /* Don't extend a locked-down transaction! */
564 [ + + ]: 3225 : if (transaction->t_state != T_RUNNING) {
565 : : jbd_debug(3, "denied handle %p %d blocks: "
566 : : "transaction not running\n", handle, nblocks);
567 : : goto error_out;
568 : : }
569 : :
570 : : spin_lock(&transaction->t_handle_lock);
571 : 3212 : wanted = atomic_add_return(nblocks,
572 : : &transaction->t_outstanding_credits);
573 : :
574 [ - + ]: 6437 : if (wanted > journal->j_max_transaction_buffers) {
575 : : jbd_debug(3, "denied handle %p %d blocks: "
576 : : "transaction too large\n", handle, nblocks);
577 : : atomic_sub(nblocks, &transaction->t_outstanding_credits);
578 : : goto unlock;
579 : : }
580 : :
581 [ - + ]: 3212 : if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) >
582 : : jbd2_log_space_left(journal)) {
583 : : jbd_debug(3, "denied handle %p %d blocks: "
584 : : "insufficient log space\n", handle, nblocks);
585 : : atomic_sub(nblocks, &transaction->t_outstanding_credits);
586 : : goto unlock;
587 : : }
588 : :
589 : 9636 : trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
590 : 3212 : transaction->t_tid,
591 : 6424 : handle->h_type, handle->h_line_no,
592 : : handle->h_buffer_credits,
593 : : nblocks);
594 : :
595 : 3212 : handle->h_buffer_credits += nblocks;
596 : 3212 : handle->h_requested_credits += nblocks;
597 : : result = 0;
598 : :
599 : : jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
600 : : unlock:
601 : : spin_unlock(&transaction->t_handle_lock);
602 : : error_out:
603 : : read_unlock(&journal->j_state_lock);
604 : 3225 : return result;
605 : : }
606 : :
607 : :
608 : : /**
609 : : * int jbd2_journal_restart() - restart a handle .
610 : : * @handle: handle to restart
611 : : * @nblocks: nr credits requested
612 : : *
613 : : * Restart a handle for a multi-transaction filesystem
614 : : * operation.
615 : : *
616 : : * If the jbd2_journal_extend() call above fails to grant new buffer credits
617 : : * to a running handle, a call to jbd2_journal_restart will commit the
618 : : * handle's transaction so far and reattach the handle to a new
619 : : * transaction capabable of guaranteeing the requested number of
620 : : * credits. We preserve reserved handle if there's any attached to the
621 : : * passed in handle.
622 : : */
623 : 0 : int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
624 : : {
625 : 9 : transaction_t *transaction = handle->h_transaction;
626 : : journal_t *journal;
627 : : tid_t tid;
628 : : int need_to_start, ret;
629 : :
630 [ - + ]: 9 : WARN_ON(!transaction);
631 : : /* If we've had an abort of any type, don't even think about
632 : : * actually doing the restart! */
633 [ + - ]: 9 : if (is_handle_aborted(handle))
634 : : return 0;
635 : 9 : journal = transaction->t_journal;
636 : :
637 : : /*
638 : : * First unlink the handle from its current transaction, and start the
639 : : * commit on that.
640 : : */
641 [ - + ]: 9 : J_ASSERT(atomic_read(&transaction->t_updates) > 0);
642 [ - + ]: 9 : J_ASSERT(journal_current_handle() == handle);
643 : :
644 : 9 : read_lock(&journal->j_state_lock);
645 : : spin_lock(&transaction->t_handle_lock);
646 : 9 : atomic_sub(handle->h_buffer_credits,
647 : : &transaction->t_outstanding_credits);
648 [ - + ]: 9 : if (handle->h_rsv_handle) {
649 : 0 : sub_reserved_credits(journal,
650 : : handle->h_rsv_handle->h_buffer_credits);
651 : : }
652 [ + + ]: 9 : if (atomic_dec_and_test(&transaction->t_updates))
653 : 8 : wake_up(&journal->j_wait_updates);
654 : 9 : tid = transaction->t_tid;
655 : : spin_unlock(&transaction->t_handle_lock);
656 : 9 : handle->h_transaction = NULL;
657 : 9 : current->journal_info = NULL;
658 : :
659 : : jbd_debug(2, "restarting handle %p\n", handle);
660 : 9 : need_to_start = !tid_geq(journal->j_commit_request, tid);
661 : : read_unlock(&journal->j_state_lock);
662 [ - + ]: 9 : if (need_to_start)
663 : 0 : jbd2_log_start_commit(journal, tid);
664 : :
665 : : lock_map_release(&handle->h_lockdep_map);
666 : 9 : handle->h_buffer_credits = nblocks;
667 : 9 : ret = start_this_handle(journal, handle, gfp_mask);
668 : 9 : return ret;
669 : : }
670 : : EXPORT_SYMBOL(jbd2__journal_restart);
671 : :
672 : :
673 : 0 : int jbd2_journal_restart(handle_t *handle, int nblocks)
674 : : {
675 : 9 : return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
676 : : }
677 : : EXPORT_SYMBOL(jbd2_journal_restart);
678 : :
679 : : /**
680 : : * void jbd2_journal_lock_updates () - establish a transaction barrier.
681 : : * @journal: Journal to establish a barrier on.
682 : : *
683 : : * This locks out any further updates from being started, and blocks
684 : : * until all existing updates have completed, returning only once the
685 : : * journal is in a quiescent state with no updates running.
686 : : *
687 : : * The journal lock should not be held on entry.
688 : : */
689 : 0 : void jbd2_journal_lock_updates(journal_t *journal)
690 : : {
691 : 0 : DEFINE_WAIT(wait);
692 : :
693 : 0 : write_lock(&journal->j_state_lock);
694 : 0 : ++journal->j_barrier_count;
695 : :
696 : : /* Wait until there are no reserved handles */
697 [ # # ]: 0 : if (atomic_read(&journal->j_reserved_credits)) {
698 : : write_unlock(&journal->j_state_lock);
699 [ # # ][ # # ]: 0 : wait_event(journal->j_wait_reserved,
700 : : atomic_read(&journal->j_reserved_credits) == 0);
701 : 0 : write_lock(&journal->j_state_lock);
702 : : }
703 : :
704 : : /* Wait until there are no running updates */
705 : : while (1) {
706 : 0 : transaction_t *transaction = journal->j_running_transaction;
707 : :
708 [ # # ]: 0 : if (!transaction)
709 : : break;
710 : :
711 : : spin_lock(&transaction->t_handle_lock);
712 : 0 : prepare_to_wait(&journal->j_wait_updates, &wait,
713 : : TASK_UNINTERRUPTIBLE);
714 [ # # ]: 0 : if (!atomic_read(&transaction->t_updates)) {
715 : : spin_unlock(&transaction->t_handle_lock);
716 : 0 : finish_wait(&journal->j_wait_updates, &wait);
717 : 0 : break;
718 : : }
719 : : spin_unlock(&transaction->t_handle_lock);
720 : : write_unlock(&journal->j_state_lock);
721 : 0 : schedule();
722 : 0 : finish_wait(&journal->j_wait_updates, &wait);
723 : 0 : write_lock(&journal->j_state_lock);
724 : 0 : }
725 : : write_unlock(&journal->j_state_lock);
726 : :
727 : : /*
728 : : * We have now established a barrier against other normal updates, but
729 : : * we also need to barrier against other jbd2_journal_lock_updates() calls
730 : : * to make sure that we serialise special journal-locked operations
731 : : * too.
732 : : */
733 : 0 : mutex_lock(&journal->j_barrier);
734 : 0 : }
735 : :
736 : : /**
737 : : * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier
738 : : * @journal: Journal to release the barrier on.
739 : : *
740 : : * Release a transaction barrier obtained with jbd2_journal_lock_updates().
741 : : *
742 : : * Should be called without the journal lock held.
743 : : */
744 : 0 : void jbd2_journal_unlock_updates (journal_t *journal)
745 : : {
746 [ # # ]: 0 : J_ASSERT(journal->j_barrier_count != 0);
747 : :
748 : 0 : mutex_unlock(&journal->j_barrier);
749 : 0 : write_lock(&journal->j_state_lock);
750 : 0 : --journal->j_barrier_count;
751 : : write_unlock(&journal->j_state_lock);
752 : 0 : wake_up(&journal->j_wait_transaction_locked);
753 : 0 : }
754 : :
755 : 0 : static void warn_dirty_buffer(struct buffer_head *bh)
756 : : {
757 : : char b[BDEVNAME_SIZE];
758 : :
759 : 0 : printk(KERN_WARNING
760 : : "JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
761 : : "There's a risk of filesystem corruption in case of system "
762 : : "crash.\n",
763 : : bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
764 : 0 : }
765 : :
766 : 0 : static int sleep_on_shadow_bh(void *word)
767 : : {
768 : 1148 : io_schedule();
769 : 1147 : return 0;
770 : : }
771 : :
772 : : /*
773 : : * If the buffer is already part of the current transaction, then there
774 : : * is nothing we need to do. If it is already part of a prior
775 : : * transaction which we are still committing to disk, then we need to
776 : : * make sure that we do not overwrite the old copy: we do copy-out to
777 : : * preserve the copy going to disk. We also account the buffer against
778 : : * the handle's metadata buffer credits (unless the buffer is already
779 : : * part of the transaction, that is).
780 : : *
781 : : */
782 : : static int
783 : 0 : do_get_write_access(handle_t *handle, struct journal_head *jh,
784 : : int force_copy)
785 : : {
786 : 0 : struct buffer_head *bh;
787 : 11856285 : transaction_t *transaction = handle->h_transaction;
788 : : journal_t *journal;
789 : : int error;
790 : : char *frozen_buffer = NULL;
791 : : int need_copy = 0;
792 : : unsigned long start_lock, time_lock;
793 : :
794 [ - + ]: 11856285 : WARN_ON(!transaction);
795 [ + - ]: 11862113 : if (is_handle_aborted(handle))
796 : : return -EROFS;
797 : 11863950 : journal = transaction->t_journal;
798 : :
799 : : jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
800 : :
801 : : JBUFFER_TRACE(jh, "entry");
802 : : repeat:
803 : : bh = jh2bh(jh);
804 : :
805 : : /* @@@ Need to check for errors here at some point. */
806 : :
807 : 11863950 : start_lock = jiffies;
808 : : lock_buffer(bh);
809 : : jbd_lock_bh_state(bh);
810 : :
811 : : /* If it takes too long to lock the buffer, trace it */
812 : 11857242 : time_lock = jbd2_time_diff(start_lock, jiffies);
813 [ + + ]: 11857242 : if (time_lock > HZ/10)
814 : 93 : trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev,
815 : 93 : jiffies_to_msecs(time_lock));
816 : :
817 : : /* We now hold the buffer lock so it is safe to query the buffer
818 : : * state. Is the buffer dirty?
819 : : *
820 : : * If so, there are two possibilities. The buffer may be
821 : : * non-journaled, and undergoing a quite legitimate writeback.
822 : : * Otherwise, it is journaled, and we don't expect dirty buffers
823 : : * in that state (the buffers should be marked JBD_Dirty
824 : : * instead.) So either the IO is being done under our own
825 : : * control and this is a bug, or it's a third party IO such as
826 : : * dump(8) (which may leave the buffer scheduled for read ---
827 : : * ie. locked but not dirty) or tune2fs (which may actually have
828 : : * the buffer dirtied, ugh.) */
829 : :
830 [ + + ]: 11856348 : if (buffer_dirty(bh)) {
831 : : /*
832 : : * First question: is this buffer already part of the current
833 : : * transaction or the existing committing transaction?
834 : : */
835 [ - + ]: 32098 : if (jh->b_transaction) {
836 [ # # ][ # # ]: 0 : J_ASSERT_JH(jh,
837 : : jh->b_transaction == transaction ||
838 : : jh->b_transaction ==
839 : : journal->j_committing_transaction);
840 [ # # ]: 0 : if (jh->b_next_transaction)
841 [ # # ]: 0 : J_ASSERT_JH(jh, jh->b_next_transaction ==
842 : : transaction);
843 : 0 : warn_dirty_buffer(bh);
844 : : }
845 : : /*
846 : : * In any case we need to clean the dirty flag and we must
847 : : * do it under the buffer lock to be sure we don't race
848 : : * with running write-out.
849 : : */
850 : : JBUFFER_TRACE(jh, "Journalling dirty buffer");
851 : : clear_buffer_dirty(bh);
852 : : set_buffer_jbddirty(bh);
853 : : }
854 : :
855 : 11856344 : unlock_buffer(bh);
856 : :
857 : : error = -EROFS;
858 [ - + ]: 11861571 : if (is_handle_aborted(handle)) {
859 : : jbd_unlock_bh_state(bh);
860 : : goto out;
861 : : }
862 : : error = 0;
863 : :
864 : : /*
865 : : * The buffer is already part of this transaction if b_transaction or
866 : : * b_next_transaction points to it
867 : : */
868 [ + + ][ + + ]: 11861571 : if (jh->b_transaction == transaction ||
869 : 162778 : jh->b_next_transaction == transaction)
870 : : goto done;
871 : :
872 : : /*
873 : : * this is the first time this transaction is touching this buffer,
874 : : * reset the modified flag
875 : : */
876 : 54735 : jh->b_modified = 0;
877 : :
878 : : /*
879 : : * If there is already a copy-out version of this buffer, then we don't
880 : : * need to make another one
881 : : */
882 [ - + ]: 54735 : if (jh->b_frozen_data) {
883 : : JBUFFER_TRACE(jh, "has frozen data");
884 [ # # ]: 0 : J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
885 : 0 : jh->b_next_transaction = transaction;
886 : 0 : goto done;
887 : : }
888 : :
889 : : /* Is there data here we need to preserve? */
890 : :
891 [ + + ][ + ]: 54735 : if (jh->b_transaction && jh->b_transaction != transaction) {
892 : : JBUFFER_TRACE(jh, "owned by older transaction");
893 [ - + ]: 11861769 : J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
894 [ - + ]: 11861769 : J_ASSERT_JH(jh, jh->b_transaction ==
895 : : journal->j_committing_transaction);
896 : :
897 : : /* There is one case we have to be very careful about.
898 : : * If the committing transaction is currently writing
899 : : * this buffer out to disk and has NOT made a copy-out,
900 : : * then we cannot modify the buffer contents at all
901 : : * right now. The essence of copy-out is that it is the
902 : : * extra copy, not the primary copy, which gets
903 : : * journaled. If the primary copy is already going to
904 : : * disk then we cannot do copy-out here. */
905 : :
906 [ + + ]: 5484 : if (buffer_shadow(bh)) {
907 : : JBUFFER_TRACE(jh, "on shadow: sleep");
908 : : jbd_unlock_bh_state(bh);
909 : : wait_on_bit(&bh->b_state, BH_Shadow,
910 : : sleep_on_shadow_bh, TASK_UNINTERRUPTIBLE);
911 : : goto repeat;
912 : : }
913 : :
914 : : /*
915 : : * Only do the copy if the currently-owning transaction still
916 : : * needs it. If buffer isn't on BJ_Metadata list, the
917 : : * committing transaction is past that stage (here we use the
918 : : * fact that BH_Shadow is set under bh_state lock together with
919 : : * refiling to BJ_Shadow list and at this point we know the
920 : : * buffer doesn't have BH_Shadow set).
921 : : *
922 : : * Subtle point, though: if this is a get_undo_access,
923 : : * then we will be relying on the frozen_data to contain
924 : : * the new value of the committed_data record after the
925 : : * transaction, so we HAVE to force the frozen_data copy
926 : : * in that case.
927 : : */
928 [ + + ][ - + ]: 4336 : if (jh->b_jlist == BJ_Metadata || force_copy) {
929 : : JBUFFER_TRACE(jh, "generate frozen data");
930 [ + + ]: 1366 : if (!frozen_buffer) {
931 : : JBUFFER_TRACE(jh, "allocate memory for buffer");
932 : : jbd_unlock_bh_state(bh);
933 : 690 : frozen_buffer =
934 : 690 : jbd2_alloc(jh2bh(jh)->b_size,
935 : : GFP_NOFS);
936 [ + - ]: 690 : if (!frozen_buffer) {
937 : 0 : printk(KERN_ERR
938 : : "%s: OOM for frozen_buffer\n",
939 : : __func__);
940 : : JBUFFER_TRACE(jh, "oom!");
941 : : error = -ENOMEM;
942 : : jbd_lock_bh_state(bh);
943 : : goto done;
944 : : }
945 : : goto repeat;
946 : : }
947 : 676 : jh->b_frozen_data = frozen_buffer;
948 : : frozen_buffer = NULL;
949 : : need_copy = 1;
950 : : }
951 : 3646 : jh->b_next_transaction = transaction;
952 : : }
953 : :
954 : :
955 : : /*
956 : : * Finally, if the buffer is not journaled right now, we need to make
957 : : * sure it doesn't get written to disk before the caller actually
958 : : * commits the new data
959 : : */
960 [ + ]: 0 : if (!jh->b_transaction) {
961 : : JBUFFER_TRACE(jh, "no transaction");
962 [ - + ]: 49278 : J_ASSERT_JH(jh, !jh->b_next_transaction);
963 : : JBUFFER_TRACE(jh, "file as BJ_Reserved");
964 : : spin_lock(&journal->j_list_lock);
965 : 49279 : __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
966 : : spin_unlock(&journal->j_list_lock);
967 : : }
968 : :
969 : : done:
970 [ + + ]: 11859215 : if (need_copy) {
971 : : struct page *page;
972 : : int offset;
973 : : char *source;
974 : :
975 [ - + ]: 676 : J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)),
976 : : "Possible IO failure.\n");
977 : 676 : page = jh2bh(jh)->b_page;
978 : 676 : offset = offset_in_page(jh2bh(jh)->b_data);
979 : 676 : source = kmap_atomic(page);
980 : : /* Fire data frozen trigger just before we copy the data */
981 : 676 : jbd2_buffer_frozen_trigger(jh, source + offset,
982 : : jh->b_triggers);
983 : 1352 : memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
984 : 676 : kunmap_atomic(source);
985 : :
986 : : /*
987 : : * Now that the frozen data is saved off, we need to store
988 : : * any matching triggers.
989 : : */
990 : 676 : jh->b_frozen_triggers = jh->b_triggers;
991 : : }
992 : : jbd_unlock_bh_state(bh);
993 : :
994 : : /*
995 : : * If we are about to journal a buffer, then any revoke pending on it is
996 : : * no longer valid
997 : : */
998 : 11851981 : jbd2_journal_cancel_revoke(handle, jh);
999 : :
1000 : : out:
1001 [ + + ]: 11852211 : if (unlikely(frozen_buffer)) /* It's usually NULL */
1002 : 14 : jbd2_free(frozen_buffer, bh->b_size);
1003 : :
1004 : : JBUFFER_TRACE(jh, "exit");
1005 : 11852211 : return error;
1006 : : }
1007 : :
1008 : : /**
1009 : : * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
1010 : : * @handle: transaction to add buffer modifications to
1011 : : * @bh: bh to be used for metadata writes
1012 : : *
1013 : : * Returns an error code or 0 on success.
1014 : : *
1015 : : * In full data journalling mode the buffer may be of type BJ_AsyncData,
1016 : : * because we're write()ing a buffer which is also part of a shared mapping.
1017 : : */
1018 : :
1019 : 0 : int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
1020 : : {
1021 : 11857965 : struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1022 : : int rc;
1023 : :
1024 : : /* We do not want to get caught playing with fields which the
1025 : : * log thread also manipulates. Make sure that the buffer
1026 : : * completes any outstanding IO before proceeding. */
1027 : 11855333 : rc = do_get_write_access(handle, jh, 0);
1028 : 11853324 : jbd2_journal_put_journal_head(jh);
1029 : 11846058 : return rc;
1030 : : }
1031 : :
1032 : :
1033 : : /*
1034 : : * When the user wants to journal a newly created buffer_head
1035 : : * (ie. getblk() returned a new buffer and we are going to populate it
1036 : : * manually rather than reading off disk), then we need to keep the
1037 : : * buffer_head locked until it has been completely filled with new
1038 : : * data. In this case, we should be able to make the assertion that
1039 : : * the bh is not already part of an existing transaction.
1040 : : *
1041 : : * The buffer should already be locked by the caller by this point.
1042 : : * There is no lock ranking violation: it was a newly created,
1043 : : * unlocked buffer beforehand. */
1044 : :
1045 : : /**
1046 : : * int jbd2_journal_get_create_access () - notify intent to use newly created bh
1047 : : * @handle: transaction to new buffer to
1048 : : * @bh: new buffer.
1049 : : *
1050 : : * Call this if you create a new bh.
1051 : : */
1052 : 0 : int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
1053 : : {
1054 : 35597 : transaction_t *transaction = handle->h_transaction;
1055 : : journal_t *journal;
1056 : 35597 : struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1057 : : int err;
1058 : :
1059 : : jbd_debug(5, "journal_head %p\n", jh);
1060 [ - + ]: 35618 : WARN_ON(!transaction);
1061 : : err = -EROFS;
1062 [ + - ]: 35622 : if (is_handle_aborted(handle))
1063 : : goto out;
1064 : 35622 : journal = transaction->t_journal;
1065 : : err = 0;
1066 : :
1067 : : JBUFFER_TRACE(jh, "entry");
1068 : : /*
1069 : : * The buffer may already belong to this transaction due to pre-zeroing
1070 : : * in the filesystem's new_block code. It may also be on the previous,
1071 : : * committing transaction's lists, but it HAS to be in Forget state in
1072 : : * that case: the transaction must have deleted the buffer for it to be
1073 : : * reused here.
1074 : : */
1075 : : jbd_lock_bh_state(bh);
1076 : : spin_lock(&journal->j_list_lock);
1077 [ + + ][ + + ]: 71302 : J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
[ - + ][ # # ]
[ # # ][ # # ]
1078 : : jh->b_transaction == NULL ||
1079 : : (jh->b_transaction == journal->j_committing_transaction &&
1080 : : jh->b_jlist == BJ_Forget)));
1081 : :
1082 [ - + ]: 35705 : J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
1083 [ - + ]: 35705 : J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
1084 : :
1085 [ + - ]: 35705 : if (jh->b_transaction == NULL) {
1086 : : /*
1087 : : * Previous jbd2_journal_forget() could have left the buffer
1088 : : * with jbddirty bit set because it was being committed. When
1089 : : * the commit finished, we've filed the buffer for
1090 : : * checkpointing and marked it dirty. Now we are reallocating
1091 : : * the buffer so the transaction freeing it must have
1092 : : * committed and so it's safe to clear the dirty bit.
1093 : : */
1094 : : clear_buffer_dirty(jh2bh(jh));
1095 : : /* first access by this transaction */
1096 : 35705 : jh->b_modified = 0;
1097 : :
1098 : : JBUFFER_TRACE(jh, "file as BJ_Reserved");
1099 : 35705 : __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
1100 [ # # ]: 0 : } else if (jh->b_transaction == journal->j_committing_transaction) {
1101 : : /* first access by this transaction */
1102 : 0 : jh->b_modified = 0;
1103 : :
1104 : : JBUFFER_TRACE(jh, "set next transaction");
1105 : 0 : jh->b_next_transaction = transaction;
1106 : : }
1107 : : spin_unlock(&journal->j_list_lock);
1108 : : jbd_unlock_bh_state(bh);
1109 : :
1110 : : /*
1111 : : * akpm: I added this. ext3_alloc_branch can pick up new indirect
1112 : : * blocks which contain freed but then revoked metadata. We need
1113 : : * to cancel the revoke in case we end up freeing it yet again
1114 : : * and the reallocating as data - this would cause a second revoke,
1115 : : * which hits an assertion error.
1116 : : */
1117 : : JBUFFER_TRACE(jh, "cancelling revoke");
1118 : 35705 : jbd2_journal_cancel_revoke(handle, jh);
1119 : : out:
1120 : 35704 : jbd2_journal_put_journal_head(jh);
1121 : 35697 : return err;
1122 : : }
1123 : :
1124 : : /**
1125 : : * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with
1126 : : * non-rewindable consequences
1127 : : * @handle: transaction
1128 : : * @bh: buffer to undo
1129 : : *
1130 : : * Sometimes there is a need to distinguish between metadata which has
1131 : : * been committed to disk and that which has not. The ext3fs code uses
1132 : : * this for freeing and allocating space, we have to make sure that we
1133 : : * do not reuse freed space until the deallocation has been committed,
1134 : : * since if we overwrote that space we would make the delete
1135 : : * un-rewindable in case of a crash.
1136 : : *
1137 : : * To deal with that, jbd2_journal_get_undo_access requests write access to a
1138 : : * buffer for parts of non-rewindable operations such as delete
1139 : : * operations on the bitmaps. The journaling code must keep a copy of
1140 : : * the buffer's contents prior to the undo_access call until such time
1141 : : * as we know that the buffer has definitely been committed to disk.
1142 : : *
1143 : : * We never need to know which transaction the committed data is part
1144 : : * of, buffers touched here are guaranteed to be dirtied later and so
1145 : : * will be committed to a new transaction in due course, at which point
1146 : : * we can discard the old committed data pointer.
1147 : : *
1148 : : * Returns error number or 0 on success.
1149 : : */
1150 : 0 : int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
1151 : : {
1152 : : int err;
1153 : 0 : struct journal_head *jh = jbd2_journal_add_journal_head(bh);
1154 : : char *committed_data = NULL;
1155 : :
1156 : : JBUFFER_TRACE(jh, "entry");
1157 : :
1158 : : /*
1159 : : * Do this first --- it can drop the journal lock, so we want to
1160 : : * make sure that obtaining the committed_data is done
1161 : : * atomically wrt. completion of any outstanding commits.
1162 : : */
1163 : 0 : err = do_get_write_access(handle, jh, 1);
1164 [ # # ]: 0 : if (err)
1165 : : goto out;
1166 : :
1167 : : repeat:
1168 [ # # ]: 0 : if (!jh->b_committed_data) {
1169 : 0 : committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS);
1170 [ # # ]: 0 : if (!committed_data) {
1171 : 0 : printk(KERN_ERR "%s: No memory for committed data\n",
1172 : : __func__);
1173 : : err = -ENOMEM;
1174 : 0 : goto out;
1175 : : }
1176 : : }
1177 : :
1178 : : jbd_lock_bh_state(bh);
1179 [ # # ]: 0 : if (!jh->b_committed_data) {
1180 : : /* Copy out the current buffer contents into the
1181 : : * preserved, committed copy. */
1182 : : JBUFFER_TRACE(jh, "generate b_committed data");
1183 [ # # ]: 0 : if (!committed_data) {
1184 : : jbd_unlock_bh_state(bh);
1185 : : goto repeat;
1186 : : }
1187 : :
1188 : 0 : jh->b_committed_data = committed_data;
1189 : : committed_data = NULL;
1190 : 0 : memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
1191 : : }
1192 : : jbd_unlock_bh_state(bh);
1193 : : out:
1194 : 0 : jbd2_journal_put_journal_head(jh);
1195 [ # # ]: 0 : if (unlikely(committed_data))
1196 : 0 : jbd2_free(committed_data, bh->b_size);
1197 : 0 : return err;
1198 : : }
1199 : :
1200 : : /**
1201 : : * void jbd2_journal_set_triggers() - Add triggers for commit writeout
1202 : : * @bh: buffer to trigger on
1203 : : * @type: struct jbd2_buffer_trigger_type containing the trigger(s).
1204 : : *
1205 : : * Set any triggers on this journal_head. This is always safe, because
1206 : : * triggers for a committing buffer will be saved off, and triggers for
1207 : : * a running transaction will match the buffer in that transaction.
1208 : : *
1209 : : * Call with NULL to clear the triggers.
1210 : : */
1211 : 0 : void jbd2_journal_set_triggers(struct buffer_head *bh,
1212 : : struct jbd2_buffer_trigger_type *type)
1213 : : {
1214 : 0 : struct journal_head *jh = jbd2_journal_grab_journal_head(bh);
1215 : :
1216 [ # # ][ # # ]: 0 : if (WARN_ON(!jh))
1217 : 0 : return;
1218 : 0 : jh->b_triggers = type;
1219 : 0 : jbd2_journal_put_journal_head(jh);
1220 : : }
1221 : :
1222 : 0 : void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
1223 : : struct jbd2_buffer_trigger_type *triggers)
1224 : : {
1225 : : struct buffer_head *bh = jh2bh(jh);
1226 : :
1227 [ - + ]: 51713 : if (!triggers || !triggers->t_frozen)
[ # # - + ]
[ # # ]
1228 : 0 : return;
1229 : :
1230 : 0 : triggers->t_frozen(triggers, bh, mapped_data, bh->b_size);
1231 : : }
1232 : :
1233 : 0 : void jbd2_buffer_abort_trigger(struct journal_head *jh,
1234 : : struct jbd2_buffer_trigger_type *triggers)
1235 : : {
1236 [ # # ][ # # ]: 0 : if (!triggers || !triggers->t_abort)
1237 : 0 : return;
1238 : :
1239 : 0 : triggers->t_abort(triggers, jh2bh(jh));
1240 : : }
1241 : :
1242 : :
1243 : :
1244 : : /**
1245 : : * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata
1246 : : * @handle: transaction to add buffer to.
1247 : : * @bh: buffer to mark
1248 : : *
1249 : : * mark dirty metadata which needs to be journaled as part of the current
1250 : : * transaction.
1251 : : *
1252 : : * The buffer must have previously had jbd2_journal_get_write_access()
1253 : : * called so that it has a valid journal_head attached to the buffer
1254 : : * head.
1255 : : *
1256 : : * The buffer is placed on the transaction's metadata list and is marked
1257 : : * as belonging to the transaction.
1258 : : *
1259 : : * Returns error number or 0 on success.
1260 : : *
1261 : : * Special care needs to be taken if the buffer already belongs to the
1262 : : * current committing transaction (in which case we should have frozen
1263 : : * data present for that commit). In that case, we don't relink the
1264 : : * buffer: that only gets done when the old transaction finally
1265 : : * completes its commit.
1266 : : */
1267 : 0 : int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
1268 : : {
1269 : 11843897 : transaction_t *transaction = handle->h_transaction;
1270 : : journal_t *journal;
1271 : : struct journal_head *jh;
1272 : : int ret = 0;
1273 : :
1274 [ - + ]: 11843897 : WARN_ON(!transaction);
1275 [ + - ]: 11853539 : if (is_handle_aborted(handle))
1276 : : return -EROFS;
1277 : 11853539 : journal = transaction->t_journal;
1278 : 11853539 : jh = jbd2_journal_grab_journal_head(bh);
1279 [ + ]: 11852639 : if (!jh) {
1280 : : ret = -EUCLEAN;
1281 : : goto out;
1282 : : }
1283 : : jbd_debug(5, "journal_head %p\n", jh);
1284 : : JBUFFER_TRACE(jh, "entry");
1285 : :
1286 : : jbd_lock_bh_state(bh);
1287 : :
1288 [ + + ]: 11851945 : if (jh->b_modified == 0) {
1289 : : /*
1290 : : * This buffer's got modified and becoming part
1291 : : * of the transaction. This needs to be done
1292 : : * once a transaction -bzzz
1293 : : */
1294 : 88572 : jh->b_modified = 1;
1295 [ + ]: 88572 : if (handle->h_buffer_credits <= 0) {
1296 : : ret = -ENOSPC;
1297 : : goto out_unlock_bh;
1298 : : }
1299 : 88599 : handle->h_buffer_credits--;
1300 : : }
1301 : :
1302 : : /*
1303 : : * fastpath, to avoid expensive locking. If this buffer is already
1304 : : * on the running transaction's metadata list there is nothing to do.
1305 : : * Nobody can take it off again because there is a handle open.
1306 : : * I _think_ we're OK here with SMP barriers - a mistaken decision will
1307 : : * result in this test being false, so we go in and take the locks.
1308 : : */
1309 [ + + ][ + + ]: 11851972 : if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
1310 : : JBUFFER_TRACE(jh, "fastpath");
1311 [ - + ]: 11659458 : if (unlikely(jh->b_transaction !=
1312 : : journal->j_running_transaction)) {
1313 [ # # ][ # # ]: 0 : printk(KERN_ERR "JBD2: %s: "
1314 : : "jh->b_transaction (%llu, %p, %u) != "
1315 : : "journal->j_running_transaction (%p, %u)",
1316 : 0 : journal->j_devname,
1317 : : (unsigned long long) bh->b_blocknr,
1318 : : jh->b_transaction,
1319 : : jh->b_transaction ? jh->b_transaction->t_tid : 0,
1320 : : journal->j_running_transaction,
1321 : : journal->j_running_transaction ?
1322 : : journal->j_running_transaction->t_tid : 0);
1323 : : ret = -EINVAL;
1324 : : }
1325 : : goto out_unlock_bh;
1326 : : }
1327 : :
1328 : : set_buffer_jbddirty(bh);
1329 : :
1330 : : /*
1331 : : * Metadata already on the current transaction list doesn't
1332 : : * need to be filed. Metadata on another transaction's list must
1333 : : * be committing, and will be refiled once the commit completes:
1334 : : * leave it alone for now.
1335 : : */
1336 [ + + ]: 196522 : if (jh->b_transaction != transaction) {
1337 : : JBUFFER_TRACE(jh, "already on other transaction");
1338 [ - + ]: 111599 : if (unlikely(jh->b_transaction !=
1339 : : journal->j_committing_transaction)) {
1340 [ # # ][ # # ]: 0 : printk(KERN_ERR "JBD2: %s: "
1341 : : "jh->b_transaction (%llu, %p, %u) != "
1342 : : "journal->j_committing_transaction (%p, %u)",
1343 : 0 : journal->j_devname,
1344 : : (unsigned long long) bh->b_blocknr,
1345 : : jh->b_transaction,
1346 : : jh->b_transaction ? jh->b_transaction->t_tid : 0,
1347 : : journal->j_committing_transaction,
1348 : : journal->j_committing_transaction ?
1349 : : journal->j_committing_transaction->t_tid : 0);
1350 : : ret = -EINVAL;
1351 : : }
1352 [ - + ]: 111599 : if (unlikely(jh->b_next_transaction != transaction)) {
1353 [ # # ]: 0 : printk(KERN_ERR "JBD2: %s: "
1354 : : "jh->b_next_transaction (%llu, %p, %u) != "
1355 : : "transaction (%p, %u)",
1356 : 0 : journal->j_devname,
1357 : : (unsigned long long) bh->b_blocknr,
1358 : : jh->b_next_transaction,
1359 : : jh->b_next_transaction ?
1360 : : jh->b_next_transaction->t_tid : 0,
1361 : : transaction, transaction->t_tid);
1362 : : ret = -EINVAL;
1363 : : }
1364 : : /* And this case is illegal: we can't reuse another
1365 : : * transaction's data buffer, ever. */
1366 : : goto out_unlock_bh;
1367 : : }
1368 : :
1369 : : /* That test should have eliminated the following case: */
1370 [ - + ]: 84923 : J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
1371 : :
1372 : : JBUFFER_TRACE(jh, "file as BJ_Metadata");
1373 : : spin_lock(&journal->j_list_lock);
1374 : 84972 : __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
1375 : : spin_unlock(&journal->j_list_lock);
1376 : : out_unlock_bh:
1377 : : jbd_unlock_bh_state(bh);
1378 : 11850965 : jbd2_journal_put_journal_head(jh);
1379 : : out:
1380 : : JBUFFER_TRACE(jh, "exit");
1381 : 11850788 : return ret;
1382 : : }
1383 : :
1384 : : /**
1385 : : * void jbd2_journal_forget() - bforget() for potentially-journaled buffers.
1386 : : * @handle: transaction handle
1387 : : * @bh: bh to 'forget'
1388 : : *
1389 : : * We can only do the bforget if there are no commits pending against the
1390 : : * buffer. If the buffer is dirty in the current running transaction we
1391 : : * can safely unlink it.
1392 : : *
1393 : : * bh may not be a journalled buffer at all - it may be a non-JBD
1394 : : * buffer which came off the hashtable. Check for this.
1395 : : *
1396 : : * Decrements bh->b_count by one.
1397 : : *
1398 : : * Allow this call even if the handle has aborted --- it may be part of
1399 : : * the caller's cleanup after an abort.
1400 : : */
1401 : 0 : int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
1402 : : {
1403 : 35835 : transaction_t *transaction = handle->h_transaction;
1404 : : journal_t *journal;
1405 : : struct journal_head *jh;
1406 : : int drop_reserve = 0;
1407 : : int err = 0;
1408 : : int was_modified = 0;
1409 : :
1410 [ - + ]: 35835 : WARN_ON(!transaction);
1411 [ + - ]: 35859 : if (is_handle_aborted(handle))
1412 : : return -EROFS;
1413 : 35859 : journal = transaction->t_journal;
1414 : :
1415 : : BUFFER_TRACE(bh, "entry");
1416 : :
1417 : : jbd_lock_bh_state(bh);
1418 : : spin_lock(&journal->j_list_lock);
1419 : :
1420 [ + + ]: 35862 : if (!buffer_jbd(bh))
1421 : : goto not_jbd;
1422 : : jh = bh2jh(bh);
1423 : :
1424 : : /* Critical error: attempting to delete a bitmap buffer, maybe?
1425 : : * Don't do any jbd operations, and return an error. */
1426 [ - + ][ + - ]: 35624 : if (!J_EXPECT_JH(jh, !jh->b_committed_data,
1427 : : "inconsistent data on disk")) {
1428 : : err = -EIO;
1429 : : goto not_jbd;
1430 : : }
1431 : :
1432 : : /* keep track of whether or not this transaction modified us */
1433 : 35624 : was_modified = jh->b_modified;
1434 : :
1435 : : /*
1436 : : * The buffer's going from the transaction, we must drop
1437 : : * all references -bzzz
1438 : : */
1439 : 35624 : jh->b_modified = 0;
1440 : :
1441 [ + + ]: 35624 : if (jh->b_transaction == transaction) {
1442 [ - + ]: 35498 : J_ASSERT_JH(jh, !jh->b_frozen_data);
1443 : :
1444 : : /* If we are forgetting a buffer which is already part
1445 : : * of this transaction, then we can just drop it from
1446 : : * the transaction immediately. */
1447 : : clear_buffer_dirty(bh);
1448 : : clear_buffer_jbddirty(bh);
1449 : :
1450 : : JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
1451 : :
1452 : : /*
1453 : : * we only want to drop a reference if this transaction
1454 : : * modified the buffer
1455 : : */
1456 [ + + ]: 35498 : if (was_modified)
1457 : : drop_reserve = 1;
1458 : :
1459 : : /*
1460 : : * We are no longer going to journal this buffer.
1461 : : * However, the commit of this transaction is still
1462 : : * important to the buffer: the delete that we are now
1463 : : * processing might obsolete an old log entry, so by
1464 : : * committing, we can satisfy the buffer's checkpoint.
1465 : : *
1466 : : * So, if we have a checkpoint on the buffer, we should
1467 : : * now refile the buffer on our BJ_Forget list so that
1468 : : * we know to remove the checkpoint after we commit.
1469 : : */
1470 : :
1471 [ + + ]: 35498 : if (jh->b_cp_transaction) {
1472 : 515 : __jbd2_journal_temp_unlink_buffer(jh);
1473 : 515 : __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
1474 : : } else {
1475 : : __jbd2_journal_unfile_buffer(jh);
1476 [ + - ]: 34983 : if (!buffer_jbd(bh)) {
1477 : : spin_unlock(&journal->j_list_lock);
1478 : : jbd_unlock_bh_state(bh);
1479 : 34983 : __bforget(bh);
1480 : 34983 : goto drop;
1481 : : }
1482 : : }
1483 [ + + ]: 126 : } else if (jh->b_transaction) {
1484 [ - + ]: 37 : J_ASSERT_JH(jh, (jh->b_transaction ==
1485 : : journal->j_committing_transaction));
1486 : : /* However, if the buffer is still owned by a prior
1487 : : * (committing) transaction, we can't drop it yet... */
1488 : : JBUFFER_TRACE(jh, "belongs to older transaction");
1489 : : /* ... but we CAN drop it from the new transaction if we
1490 : : * have also modified it since the original commit. */
1491 : :
1492 [ + + ]: 37 : if (jh->b_next_transaction) {
1493 [ - + ]: 24 : J_ASSERT(jh->b_next_transaction == transaction);
1494 : 24 : jh->b_next_transaction = NULL;
1495 : :
1496 : : /*
1497 : : * only drop a reference if this transaction modified
1498 : : * the buffer
1499 : : */
1500 [ + + ]: 24 : if (was_modified)
1501 : : drop_reserve = 1;
1502 : : }
1503 : : }
1504 : :
1505 : : not_jbd:
1506 : : spin_unlock(&journal->j_list_lock);
1507 : : jbd_unlock_bh_state(bh);
1508 : 879 : __brelse(bh);
1509 : : drop:
1510 [ + + ]: 35862 : if (drop_reserve) {
1511 : : /* no need to reserve log space for this block -bzzz */
1512 : 35502 : handle->h_buffer_credits++;
1513 : : }
1514 : 35862 : return err;
1515 : : }
1516 : :
1517 : : /**
1518 : : * int jbd2_journal_stop() - complete a transaction
1519 : : * @handle: tranaction to complete.
1520 : : *
1521 : : * All done for a particular handle.
1522 : : *
1523 : : * There is not much action needed here. We just return any remaining
1524 : : * buffer credits to the transaction and remove the handle. The only
1525 : : * complication is that we need to start a commit operation if the
1526 : : * filesystem is marked for synchronous update.
1527 : : *
1528 : : * jbd2_journal_stop itself will not usually return an error, but it may
1529 : : * do so in unusual circumstances. In particular, expect it to
1530 : : * return -EIO if a jbd2_journal_abort has been executed since the
1531 : : * transaction began.
1532 : : */
1533 : 0 : int jbd2_journal_stop(handle_t *handle)
1534 : : {
1535 : 12477299 : transaction_t *transaction = handle->h_transaction;
1536 : : journal_t *journal;
1537 : : int err = 0, wait_for_commit = 0;
1538 : : tid_t tid;
1539 : : pid_t pid;
1540 : :
1541 [ + ]: 12477299 : if (!transaction)
1542 : : goto free_and_exit;
1543 : 12482905 : journal = transaction->t_journal;
1544 : :
1545 [ - + ]: 12482905 : J_ASSERT(journal_current_handle() == handle);
1546 : :
1547 [ + + ]: 12482905 : if (is_handle_aborted(handle))
1548 : : err = -EIO;
1549 : : else
1550 [ - + ]: 12482570 : J_ASSERT(atomic_read(&transaction->t_updates) > 0);
1551 : :
1552 [ + + ]: 12482905 : if (--handle->h_ref > 0) {
1553 : : jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
1554 : : handle->h_ref);
1555 : : return err;
1556 : : }
1557 : :
1558 : : jbd_debug(4, "Handle %p going down\n", handle);
1559 : 58301145 : trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
1560 : 8328735 : transaction->t_tid,
1561 : 16657470 : handle->h_type, handle->h_line_no,
1562 : 8328735 : jiffies - handle->h_start_jiffies,
1563 : 16657470 : handle->h_sync, handle->h_requested_credits,
1564 : 8328735 : (handle->h_requested_credits -
1565 : 8328735 : handle->h_buffer_credits));
1566 : :
1567 : : /*
1568 : : * Implement synchronous transaction batching. If the handle
1569 : : * was synchronous, don't force a commit immediately. Let's
1570 : : * yield and let another thread piggyback onto this
1571 : : * transaction. Keep doing that while new threads continue to
1572 : : * arrive. It doesn't cost much - we're about to run a commit
1573 : : * and sleep on IO anyway. Speeds up many-threaded, many-dir
1574 : : * operations by 30x or more...
1575 : : *
1576 : : * We try and optimize the sleep time against what the
1577 : : * underlying disk can do, instead of having a static sleep
1578 : : * time. This is useful for the case where our storage is so
1579 : : * fast that it is more optimal to go ahead and force a flush
1580 : : * and wait for the transaction to be committed than it is to
1581 : : * wait for an arbitrary amount of time for new writers to
1582 : : * join the transaction. We achieve this by measuring how
1583 : : * long it takes to commit a transaction, and compare it with
1584 : : * how long this transaction has been running, and if run time
1585 : : * < commit time then we sleep for the delta and commit. This
1586 : : * greatly helps super fast disks that would see slowdowns as
1587 : : * more threads started doing fsyncs.
1588 : : *
1589 : : * But don't do this if this process was the most recent one
1590 : : * to perform a synchronous write. We do this to detect the
1591 : : * case where a single process is doing a stream of sync
1592 : : * writes. No point in waiting for joiners in that case.
1593 : : */
1594 : 8330606 : pid = current->pid;
1595 [ - + ][ # # ]: 8330606 : if (handle->h_sync && journal->j_last_sync_writer != pid) {
1596 : : u64 commit_time, trans_time;
1597 : :
1598 : 0 : journal->j_last_sync_writer = pid;
1599 : :
1600 : 0 : read_lock(&journal->j_state_lock);
1601 : 0 : commit_time = journal->j_average_commit_time;
1602 : : read_unlock(&journal->j_state_lock);
1603 : :
1604 : 0 : trans_time = ktime_to_ns(ktime_sub(ktime_get(),
1605 : : transaction->t_start_time));
1606 : :
1607 : 0 : commit_time = max_t(u64, commit_time,
1608 : : 1000*journal->j_min_batch_time);
1609 : 0 : commit_time = min_t(u64, commit_time,
1610 : : 1000*journal->j_max_batch_time);
1611 : :
1612 [ # # ]: 0 : if (trans_time < commit_time) {
1613 : 0 : ktime_t expires = ktime_add_ns(ktime_get(),
1614 : : commit_time);
1615 : 0 : set_current_state(TASK_UNINTERRUPTIBLE);
1616 : 0 : schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
1617 : : }
1618 : : }
1619 : :
1620 [ - + ]: 8330606 : if (handle->h_sync)
1621 : 0 : transaction->t_synchronous_commit = 1;
1622 : 8330606 : current->journal_info = NULL;
1623 : 8330606 : atomic_sub(handle->h_buffer_credits,
1624 : : &transaction->t_outstanding_credits);
1625 : :
1626 : : /*
1627 : : * If the handle is marked SYNC, we need to set another commit
1628 : : * going! We also want to force a commit if the current
1629 : : * transaction is occupying too much of the log, or if the
1630 : : * transaction is too old now.
1631 : : */
1632 [ + ][ + + ]: 8332333 : if (handle->h_sync ||
1633 : 8332518 : (atomic_read(&transaction->t_outstanding_credits) >
1634 : 8332518 : journal->j_max_transaction_buffers) ||
1635 [ + + ]: 8332009 : time_after_eq(jiffies, transaction->t_expires)) {
1636 : : /* Do this even for aborted journals: an abort still
1637 : : * completes the commit thread, it just doesn't write
1638 : : * anything to disk. */
1639 : :
1640 : : jbd_debug(2, "transaction too old, requesting commit for "
1641 : : "handle %p\n", handle);
1642 : : /* This is non-blocking */
1643 : 5410 : jbd2_log_start_commit(journal, transaction->t_tid);
1644 : :
1645 : : /*
1646 : : * Special case: JBD2_SYNC synchronous updates require us
1647 : : * to wait for the commit to complete.
1648 : : */
1649 [ - + ][ # # ]: 3217 : if (handle->h_sync && !(current->flags & PF_MEMALLOC))
1650 : : wait_for_commit = 1;
1651 : : }
1652 : :
1653 : : /*
1654 : : * Once we drop t_updates, if it goes to zero the transaction
1655 : : * could start committing on us and eventually disappear. So
1656 : : * once we do this, we must not dereference transaction
1657 : : * pointer again.
1658 : : */
1659 : 8330140 : tid = transaction->t_tid;
1660 [ + + ]: 8329302 : if (atomic_dec_and_test(&transaction->t_updates)) {
1661 : 7592422 : wake_up(&journal->j_wait_updates);
1662 [ - + ]: 7592422 : if (journal->j_barrier_count)
1663 : 0 : wake_up(&journal->j_wait_transaction_locked);
1664 : : }
1665 : :
1666 [ - + ]: 8327079 : if (wait_for_commit)
1667 : 0 : err = jbd2_log_wait_commit(journal, tid);
1668 : :
1669 : : lock_map_release(&handle->h_lockdep_map);
1670 : :
1671 [ - + ]: 8327079 : if (handle->h_rsv_handle)
1672 : 0 : jbd2_journal_free_reserved(handle->h_rsv_handle);
1673 : : free_and_exit:
1674 : : jbd2_free_handle(handle);
1675 : 8333697 : return err;
1676 : : }
1677 : :
1678 : : /*
1679 : : *
1680 : : * List management code snippets: various functions for manipulating the
1681 : : * transaction buffer lists.
1682 : : *
1683 : : */
1684 : :
1685 : : /*
1686 : : * Append a buffer to a transaction list, given the transaction's list head
1687 : : * pointer.
1688 : : *
1689 : : * j_list_lock is held.
1690 : : *
1691 : : * jbd_lock_bh_state(jh2bh(jh)) is held.
1692 : : */
1693 : :
1694 : : static inline void
1695 : : __blist_add_buffer(struct journal_head **list, struct journal_head *jh)
1696 : : {
1697 [ + + ]: 277566 : if (!*list) {
1698 : 135646 : jh->b_tnext = jh->b_tprev = jh;
1699 : 135646 : *list = jh;
1700 : : } else {
1701 : : /* Insert at the tail of the list to preserve order */
1702 : 141920 : struct journal_head *first = *list, *last = first->b_tprev;
1703 : 141920 : jh->b_tprev = last;
1704 : 141920 : jh->b_tnext = first;
1705 : 141920 : last->b_tnext = first->b_tprev = jh;
1706 : : }
1707 : : }
1708 : :
1709 : : /*
1710 : : * Remove a buffer from a transaction list, given the transaction's list
1711 : : * head pointer.
1712 : : *
1713 : : * Called with j_list_lock held, and the journal may not be locked.
1714 : : *
1715 : : * jbd_lock_bh_state(jh2bh(jh)) is held.
1716 : : */
1717 : :
1718 : : static inline void
1719 : : __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
1720 : : {
1721 [ + + ]: 277388 : if (*list == jh) {
1722 : 205163 : *list = jh->b_tnext;
1723 [ + + ]: 205163 : if (*list == jh)
1724 : 135645 : *list = NULL;
1725 : : }
1726 : 277388 : jh->b_tprev->b_tnext = jh->b_tnext;
1727 : 277388 : jh->b_tnext->b_tprev = jh->b_tprev;
1728 : : }
1729 : :
1730 : : /*
1731 : : * Remove a buffer from the appropriate transaction list.
1732 : : *
1733 : : * Note that this function can *change* the value of
1734 : : * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or
1735 : : * t_reserved_list. If the caller is holding onto a copy of one of these
1736 : : * pointers, it could go bad. Generally the caller needs to re-read the
1737 : : * pointer from the transaction_t.
1738 : : *
1739 : : * Called under j_list_lock.
1740 : : */
1741 : 0 : static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
1742 : : {
1743 : : struct journal_head **list = NULL;
1744 : : transaction_t *transaction;
1745 : : struct buffer_head *bh = jh2bh(jh);
1746 : :
1747 [ - + ]: 281572 : J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
1748 : 281572 : transaction = jh->b_transaction;
1749 [ + + ]: 281572 : if (transaction)
1750 [ - + ]: 281530 : assert_spin_locked(&transaction->t_journal->j_list_lock);
1751 : :
1752 [ - + ]: 281572 : J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
1753 [ + + ]: 281572 : if (jh->b_jlist != BJ_None)
1754 [ - + ]: 277388 : J_ASSERT_JH(jh, transaction != NULL);
1755 : :
1756 [ + + + + : 281572 : switch (jh->b_jlist) {
- + ]
1757 : : case BJ_None:
1758 : 0 : return;
1759 : : case BJ_Metadata:
1760 : 88415 : transaction->t_nr_buffers--;
1761 [ - + ]: 88415 : J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
1762 : 88415 : list = &transaction->t_buffers;
1763 : 88415 : break;
1764 : : case BJ_Forget:
1765 : 52275 : list = &transaction->t_forget;
1766 : 52275 : break;
1767 : : case BJ_Shadow:
1768 : 51713 : list = &transaction->t_shadow_list;
1769 : 51713 : break;
1770 : : case BJ_Reserved:
1771 : 84985 : list = &transaction->t_reserved_list;
1772 : 84985 : break;
1773 : : }
1774 : :
1775 : : __blist_del_buffer(list, jh);
1776 : 277388 : jh->b_jlist = BJ_None;
1777 [ + + ]: 277388 : if (test_clear_buffer_jbddirty(bh))
1778 : 49303 : mark_buffer_dirty(bh); /* Expose it to the VM */
1779 : : }
1780 : :
1781 : : /*
1782 : : * Remove buffer from all transactions.
1783 : : *
1784 : : * Called with bh_state lock and j_list_lock
1785 : : *
1786 : : * jh and bh may be already freed when this function returns.
1787 : : */
1788 : : static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
1789 : : {
1790 : 84848 : __jbd2_journal_temp_unlink_buffer(jh);
1791 : 84848 : jh->b_transaction = NULL;
1792 : 84848 : jbd2_journal_put_journal_head(jh);
1793 : : }
1794 : :
1795 : 0 : void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
1796 : : {
1797 : : struct buffer_head *bh = jh2bh(jh);
1798 : :
1799 : : /* Get reference so that buffer cannot be freed before we unlock it */
1800 : : get_bh(bh);
1801 : : jbd_lock_bh_state(bh);
1802 : : spin_lock(&journal->j_list_lock);
1803 : : __jbd2_journal_unfile_buffer(jh);
1804 : : spin_unlock(&journal->j_list_lock);
1805 : : jbd_unlock_bh_state(bh);
1806 : 0 : __brelse(bh);
1807 : 0 : }
1808 : :
1809 : : /*
1810 : : * Called from jbd2_journal_try_to_free_buffers().
1811 : : *
1812 : : * Called under jbd_lock_bh_state(bh)
1813 : : */
1814 : : static void
1815 : 0 : __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
1816 : : {
1817 : : struct journal_head *jh;
1818 : :
1819 : : jh = bh2jh(bh);
1820 : :
1821 [ + - ][ + - ]: 475 : if (buffer_locked(bh) || buffer_dirty(bh))
1822 : : goto out;
1823 : :
1824 [ + - ]: 475 : if (jh->b_next_transaction != NULL)
1825 : : goto out;
1826 : :
1827 : : spin_lock(&journal->j_list_lock);
1828 [ + + ][ + - ]: 475 : if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
1829 : : /* written-back checkpointed metadata buffer */
1830 : : JBUFFER_TRACE(jh, "remove from checkpoint list");
1831 : 31 : __jbd2_journal_remove_checkpoint(jh);
1832 : : }
1833 : : spin_unlock(&journal->j_list_lock);
1834 : : out:
1835 : 475 : return;
1836 : : }
1837 : :
1838 : : /**
1839 : : * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
1840 : : * @journal: journal for operation
1841 : : * @page: to try and free
1842 : : * @gfp_mask: we use the mask to detect how hard should we try to release
1843 : : * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to
1844 : : * release the buffers.
1845 : : *
1846 : : *
1847 : : * For all the buffers on this page,
1848 : : * if they are fully written out ordered data, move them onto BUF_CLEAN
1849 : : * so try_to_free_buffers() can reap them.
1850 : : *
1851 : : * This function returns non-zero if we wish try_to_free_buffers()
1852 : : * to be called. We do this if the page is releasable by try_to_free_buffers().
1853 : : * We also do it if the page has locked or dirty buffers and the caller wants
1854 : : * us to perform sync or async writeout.
1855 : : *
1856 : : * This complicates JBD locking somewhat. We aren't protected by the
1857 : : * BKL here. We wish to remove the buffer from its committing or
1858 : : * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer.
1859 : : *
1860 : : * This may *change* the value of transaction_t->t_datalist, so anyone
1861 : : * who looks at t_datalist needs to lock against this function.
1862 : : *
1863 : : * Even worse, someone may be doing a jbd2_journal_dirty_data on this
1864 : : * buffer. So we need to lock against that. jbd2_journal_dirty_data()
1865 : : * will come out of the lock with the buffer dirty, which makes it
1866 : : * ineligible for release here.
1867 : : *
1868 : : * Who else is affected by this? hmm... Really the only contender
1869 : : * is do_get_write_access() - it could be looking at the buffer while
1870 : : * journal_try_to_free_buffer() is changing its state. But that
1871 : : * cannot happen because we never reallocate freed data as metadata
1872 : : * while the data is part of a transaction. Yes?
1873 : : *
1874 : : * Return 0 on failure, 1 on success
1875 : : */
1876 : 0 : int jbd2_journal_try_to_free_buffers(journal_t *journal,
1877 : : struct page *page, gfp_t gfp_mask)
1878 : : {
1879 : : struct buffer_head *head;
1880 : : struct buffer_head *bh;
1881 : : int ret = 0;
1882 : :
1883 [ - + ]: 1833877 : J_ASSERT(PageLocked(page));
1884 : :
1885 [ - + ]: 1833877 : head = page_buffers(page);
1886 : : bh = head;
1887 : : do {
1888 : : struct journal_head *jh;
1889 : :
1890 : : /*
1891 : : * We take our own ref against the journal_head here to avoid
1892 : : * having to add tons of locking around each instance of
1893 : : * jbd2_journal_put_journal_head().
1894 : : */
1895 : 1833877 : jh = jbd2_journal_grab_journal_head(bh);
1896 [ + + ]: 1833915 : if (!jh)
1897 : 1833440 : continue;
1898 : :
1899 : : jbd_lock_bh_state(bh);
1900 : 475 : __journal_try_to_free_buffer(journal, bh);
1901 : 475 : jbd2_journal_put_journal_head(jh);
1902 : : jbd_unlock_bh_state(bh);
1903 [ + ]: 475 : if (buffer_jbd(bh))
1904 : : goto busy;
1905 [ - + ]: 1833433 : } while ((bh = bh->b_this_page) != head);
1906 : :
1907 : 1833433 : ret = try_to_free_buffers(page);
1908 : :
1909 : : busy:
1910 : 1833931 : return ret;
1911 : : }
1912 : :
1913 : : /*
1914 : : * This buffer is no longer needed. If it is on an older transaction's
1915 : : * checkpoint list we need to record it on this transaction's forget list
1916 : : * to pin this buffer (and hence its checkpointing transaction) down until
1917 : : * this transaction commits. If the buffer isn't on a checkpoint list, we
1918 : : * release it.
1919 : : * Returns non-zero if JBD no longer has an interest in the buffer.
1920 : : *
1921 : : * Called under j_list_lock.
1922 : : *
1923 : : * Called under jbd_lock_bh_state(bh).
1924 : : */
1925 : 0 : static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
1926 : : {
1927 : : int may_free = 1;
1928 : : struct buffer_head *bh = jh2bh(jh);
1929 : :
1930 [ + + ]: 1259 : if (jh->b_cp_transaction) {
1931 : : JBUFFER_TRACE(jh, "on running+cp transaction");
1932 : 42 : __jbd2_journal_temp_unlink_buffer(jh);
1933 : : /*
1934 : : * We don't want to write the buffer anymore, clear the
1935 : : * bit so that we don't confuse checks in
1936 : : * __journal_file_buffer
1937 : : */
1938 : : clear_buffer_dirty(bh);
1939 : 42 : __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
1940 : : may_free = 0;
1941 : : } else {
1942 : : JBUFFER_TRACE(jh, "on running transaction");
1943 : : __jbd2_journal_unfile_buffer(jh);
1944 : : }
1945 : 1259 : return may_free;
1946 : : }
1947 : :
1948 : : /*
1949 : : * jbd2_journal_invalidatepage
1950 : : *
1951 : : * This code is tricky. It has a number of cases to deal with.
1952 : : *
1953 : : * There are two invariants which this code relies on:
1954 : : *
1955 : : * i_size must be updated on disk before we start calling invalidatepage on the
1956 : : * data.
1957 : : *
1958 : : * This is done in ext3 by defining an ext3_setattr method which
1959 : : * updates i_size before truncate gets going. By maintaining this
1960 : : * invariant, we can be sure that it is safe to throw away any buffers
1961 : : * attached to the current transaction: once the transaction commits,
1962 : : * we know that the data will not be needed.
1963 : : *
1964 : : * Note however that we can *not* throw away data belonging to the
1965 : : * previous, committing transaction!
1966 : : *
1967 : : * Any disk blocks which *are* part of the previous, committing
1968 : : * transaction (and which therefore cannot be discarded immediately) are
1969 : : * not going to be reused in the new running transaction
1970 : : *
1971 : : * The bitmap committed_data images guarantee this: any block which is
1972 : : * allocated in one transaction and removed in the next will be marked
1973 : : * as in-use in the committed_data bitmap, so cannot be reused until
1974 : : * the next transaction to delete the block commits. This means that
1975 : : * leaving committing buffers dirty is quite safe: the disk blocks
1976 : : * cannot be reallocated to a different file and so buffer aliasing is
1977 : : * not possible.
1978 : : *
1979 : : *
1980 : : * The above applies mainly to ordered data mode. In writeback mode we
1981 : : * don't make guarantees about the order in which data hits disk --- in
1982 : : * particular we don't guarantee that new dirty data is flushed before
1983 : : * transaction commit --- so it is always safe just to discard data
1984 : : * immediately in that mode. --sct
1985 : : */
1986 : :
1987 : : /*
1988 : : * The journal_unmap_buffer helper function returns zero if the buffer
1989 : : * concerned remains pinned as an anonymous buffer belonging to an older
1990 : : * transaction.
1991 : : *
1992 : : * We're outside-transaction here. Either or both of j_running_transaction
1993 : : * and j_committing_transaction may be NULL.
1994 : : */
1995 : 0 : static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
1996 : : int partial_page)
1997 : : {
1998 : : transaction_t *transaction;
1999 : : struct journal_head *jh;
2000 : : int may_free = 1;
2001 : :
2002 : : BUFFER_TRACE(bh, "entry");
2003 : :
2004 : : /*
2005 : : * It is safe to proceed here without the j_list_lock because the
2006 : : * buffers cannot be stolen by try_to_free_buffers as long as we are
2007 : : * holding the page lock. --sct
2008 : : */
2009 : :
2010 [ + + ]: 2618 : if (!buffer_jbd(bh))
2011 : : goto zap_buffer_unlocked;
2012 : :
2013 : : /* OK, we have data buffer in journaled mode */
2014 : 1265 : write_lock(&journal->j_state_lock);
2015 : : jbd_lock_bh_state(bh);
2016 : : spin_lock(&journal->j_list_lock);
2017 : :
2018 : 1265 : jh = jbd2_journal_grab_journal_head(bh);
2019 [ + - ]: 1265 : if (!jh)
2020 : : goto zap_buffer_no_jh;
2021 : :
2022 : : /*
2023 : : * We cannot remove the buffer from checkpoint lists until the
2024 : : * transaction adding inode to orphan list (let's call it T)
2025 : : * is committed. Otherwise if the transaction changing the
2026 : : * buffer would be cleaned from the journal before T is
2027 : : * committed, a crash will cause that the correct contents of
2028 : : * the buffer will be lost. On the other hand we have to
2029 : : * clear the buffer dirty bit at latest at the moment when the
2030 : : * transaction marking the buffer as freed in the filesystem
2031 : : * structures is committed because from that moment on the
2032 : : * block can be reallocated and used by a different page.
2033 : : * Since the block hasn't been freed yet but the inode has
2034 : : * already been added to orphan list, it is safe for us to add
2035 : : * the buffer to BJ_Forget list of the newest transaction.
2036 : : *
2037 : : * Also we have to clear buffer_mapped flag of a truncated buffer
2038 : : * because the buffer_head may be attached to the page straddling
2039 : : * i_size (can happen only when blocksize < pagesize) and thus the
2040 : : * buffer_head can be reused when the file is extended again. So we end
2041 : : * up keeping around invalidated buffers attached to transactions'
2042 : : * BJ_Forget list just to stop checkpointing code from cleaning up
2043 : : * the transaction this buffer was modified in.
2044 : : */
2045 : 1265 : transaction = jh->b_transaction;
2046 [ + + ]: 1265 : if (transaction == NULL) {
2047 : : /* First case: not on any transaction. If it
2048 : : * has no checkpoint link, then we can zap it:
2049 : : * it's a writeback-mode buffer so we don't care
2050 : : * if it hits disk safely. */
2051 [ + - ]: 43 : if (!jh->b_cp_transaction) {
2052 : : JBUFFER_TRACE(jh, "not on any transaction: zap");
2053 : : goto zap_buffer;
2054 : : }
2055 : :
2056 [ + + ]: 43 : if (!buffer_dirty(bh)) {
2057 : : /* bdflush has written it. We can drop it now */
2058 : : goto zap_buffer;
2059 : : }
2060 : :
2061 : : /* OK, it must be in the journal but still not
2062 : : * written fully to disk: it's metadata or
2063 : : * journaled data... */
2064 : :
2065 [ + - ]: 42 : if (journal->j_running_transaction) {
2066 : : /* ... and once the current transaction has
2067 : : * committed, the buffer won't be needed any
2068 : : * longer. */
2069 : : JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget");
2070 : 42 : may_free = __dispose_buffer(jh,
2071 : : journal->j_running_transaction);
2072 : 42 : goto zap_buffer;
2073 : : } else {
2074 : : /* There is no currently-running transaction. So the
2075 : : * orphan record which we wrote for this file must have
2076 : : * passed into commit. We must attach this buffer to
2077 : : * the committing transaction, if it exists. */
2078 [ # # ]: 0 : if (journal->j_committing_transaction) {
2079 : : JBUFFER_TRACE(jh, "give to committing trans");
2080 : 0 : may_free = __dispose_buffer(jh,
2081 : : journal->j_committing_transaction);
2082 : 0 : goto zap_buffer;
2083 : : } else {
2084 : : /* The orphan record's transaction has
2085 : : * committed. We can cleanse this buffer */
2086 : : clear_buffer_jbddirty(bh);
2087 : : goto zap_buffer;
2088 : : }
2089 : : }
2090 [ + + ]: 1222 : } else if (transaction == journal->j_committing_transaction) {
2091 : : JBUFFER_TRACE(jh, "on committing transaction");
2092 : : /*
2093 : : * The buffer is committing, we simply cannot touch
2094 : : * it. If the page is straddling i_size we have to wait
2095 : : * for commit and try again.
2096 : : */
2097 [ - + ]: 5 : if (partial_page) {
2098 : 0 : jbd2_journal_put_journal_head(jh);
2099 : : spin_unlock(&journal->j_list_lock);
2100 : : jbd_unlock_bh_state(bh);
2101 : : write_unlock(&journal->j_state_lock);
2102 : 0 : return -EBUSY;
2103 : : }
2104 : : /*
2105 : : * OK, buffer won't be reachable after truncate. We just set
2106 : : * j_next_transaction to the running transaction (if there is
2107 : : * one) and mark buffer as freed so that commit code knows it
2108 : : * should clear dirty bits when it is done with the buffer.
2109 : : */
2110 : : set_buffer_freed(bh);
2111 [ + - ][ + - ]: 5 : if (journal->j_running_transaction && buffer_jbddirty(bh))
2112 : 5 : jh->b_next_transaction = journal->j_running_transaction;
2113 : 5 : jbd2_journal_put_journal_head(jh);
2114 : : spin_unlock(&journal->j_list_lock);
2115 : : jbd_unlock_bh_state(bh);
2116 : : write_unlock(&journal->j_state_lock);
2117 : 5 : return 0;
2118 : : } else {
2119 : : /* Good, the buffer belongs to the running transaction.
2120 : : * We are writing our own transaction's data, not any
2121 : : * previous one's, so it is safe to throw it away
2122 : : * (remember that we expect the filesystem to have set
2123 : : * i_size already for this truncate so recovery will not
2124 : : * expose the disk blocks we are discarding here.) */
2125 [ - + ]: 1217 : J_ASSERT_JH(jh, transaction == journal->j_running_transaction);
2126 : : JBUFFER_TRACE(jh, "on running transaction");
2127 : 1217 : may_free = __dispose_buffer(jh, transaction);
2128 : : }
2129 : :
2130 : : zap_buffer:
2131 : : /*
2132 : : * This is tricky. Although the buffer is truncated, it may be reused
2133 : : * if blocksize < pagesize and it is attached to the page straddling
2134 : : * EOF. Since the buffer might have been added to BJ_Forget list of the
2135 : : * running transaction, journal_get_write_access() won't clear
2136 : : * b_modified and credit accounting gets confused. So clear b_modified
2137 : : * here.
2138 : : */
2139 : 1260 : jh->b_modified = 0;
2140 : 1260 : jbd2_journal_put_journal_head(jh);
2141 : : zap_buffer_no_jh:
2142 : : spin_unlock(&journal->j_list_lock);
2143 : : jbd_unlock_bh_state(bh);
2144 : : write_unlock(&journal->j_state_lock);
2145 : : zap_buffer_unlocked:
2146 : : clear_buffer_dirty(bh);
2147 [ - + ]: 2613 : J_ASSERT_BH(bh, !buffer_jbddirty(bh));
2148 : : clear_buffer_mapped(bh);
2149 : : clear_buffer_req(bh);
2150 : : clear_buffer_new(bh);
2151 : : clear_buffer_delay(bh);
2152 : : clear_buffer_unwritten(bh);
2153 : 2613 : bh->b_bdev = NULL;
2154 : 2613 : return may_free;
2155 : : }
2156 : :
2157 : : /**
2158 : : * void jbd2_journal_invalidatepage()
2159 : : * @journal: journal to use for flush...
2160 : : * @page: page to flush
2161 : : * @offset: start of the range to invalidate
2162 : : * @length: length of the range to invalidate
2163 : : *
2164 : : * Reap page buffers containing data after in the specified range in page.
2165 : : * Can return -EBUSY if buffers are part of the committing transaction and
2166 : : * the page is straddling i_size. Caller then has to wait for current commit
2167 : : * and try again.
2168 : : */
2169 : 0 : int jbd2_journal_invalidatepage(journal_t *journal,
2170 : : struct page *page,
2171 : : unsigned int offset,
2172 : : unsigned int length)
2173 : : {
2174 : : struct buffer_head *head, *bh, *next;
2175 : 2618 : unsigned int stop = offset + length;
2176 : : unsigned int curr_off = 0;
2177 : 2618 : int partial_page = (offset || length < PAGE_CACHE_SIZE);
2178 : : int may_free = 1;
2179 : : int ret = 0;
2180 : :
2181 [ - + ]: 2618 : if (!PageLocked(page))
2182 : 0 : BUG();
2183 [ + - ]: 2618 : if (!page_has_buffers(page))
2184 : : return 0;
2185 : :
2186 [ - + ]: 2618 : BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
2187 : :
2188 : : /* We will potentially be playing with lists other than just the
2189 : : * data lists (especially for journaled data mode), so be
2190 : : * cautious in our locking. */
2191 : :
2192 [ - + ]: 2618 : head = bh = page_buffers(page);
2193 : : do {
2194 : 2618 : unsigned int next_off = curr_off + bh->b_size;
2195 : 2618 : next = bh->b_this_page;
2196 : :
2197 [ + - ]: 2618 : if (next_off > stop)
2198 : : return 0;
2199 : :
2200 [ + - ]: 2618 : if (offset <= curr_off) {
2201 : : /* This block is wholly outside the truncation point */
2202 : : lock_buffer(bh);
2203 : 2618 : ret = journal_unmap_buffer(journal, bh, partial_page);
2204 : 2618 : unlock_buffer(bh);
2205 [ + - ]: 2618 : if (ret < 0)
2206 : : return ret;
2207 : 2618 : may_free &= ret;
2208 : : }
2209 : : curr_off = next_off;
2210 : : bh = next;
2211 : :
2212 [ - + ]: 2618 : } while (bh != head);
2213 : :
2214 [ + - ]: 2618 : if (!partial_page) {
2215 [ + + ][ + + ]: 2618 : if (may_free && try_to_free_buffers(page))
2216 [ - + ]: 2570 : J_ASSERT(!page_has_buffers(page));
2217 : : }
2218 : : return 0;
2219 : : }
2220 : :
2221 : : /*
2222 : : * File a buffer on the given transaction list.
2223 : : */
2224 : 0 : void __jbd2_journal_file_buffer(struct journal_head *jh,
2225 : : transaction_t *transaction, int jlist)
2226 : : {
2227 : : struct journal_head **list = NULL;
2228 : : int was_dirty = 0;
2229 : 0 : struct buffer_head *bh = jh2bh(jh);
2230 : :
2231 [ - + ]: 277566 : J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2232 [ - + ]: 277566 : assert_spin_locked(&transaction->t_journal->j_list_lock);
2233 : :
2234 [ - + ]: 277566 : J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
2235 [ + + ][ - + ]: 277566 : J_ASSERT_JH(jh, jh->b_transaction == transaction ||
2236 : : jh->b_transaction == NULL);
2237 : :
2238 [ + + ][ + - ]: 277566 : if (jh->b_transaction && jh->b_jlist == jlist)
2239 : : return;
2240 : :
2241 [ + + ]: 277566 : if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
2242 [ + - ]: 103988 : jlist == BJ_Shadow || jlist == BJ_Forget) {
2243 : : /*
2244 : : * For metadata buffers, we track dirty bit in buffer_jbddirty
2245 : : * instead of buffer_dirty. We should not see a dirty bit set
2246 : : * here because we clear it in do_get_write_access but e.g.
2247 : : * tune2fs can modify the sb and set the dirty bit at any time
2248 : : * so we try to gracefully handle that.
2249 : : */
2250 [ - + ]: 277566 : if (buffer_dirty(bh))
2251 : 0 : warn_dirty_buffer(bh);
2252 [ + - + + ]: 555132 : if (test_clear_buffer_dirty(bh) ||
2253 : : test_clear_buffer_jbddirty(bh))
2254 : : was_dirty = 1;
2255 : : }
2256 : :
2257 [ + + ]: 277566 : if (jh->b_transaction)
2258 : 192540 : __jbd2_journal_temp_unlink_buffer(jh);
2259 : : else
2260 : 85026 : jbd2_journal_grab_journal_head(bh);
2261 : 277566 : jh->b_transaction = transaction;
2262 : :
2263 [ - + + + : 555132 : switch (jlist) {
+ - ]
2264 : : case BJ_None:
2265 [ # # ]: 0 : J_ASSERT_JH(jh, !jh->b_committed_data);
2266 [ # # ]: 0 : J_ASSERT_JH(jh, !jh->b_frozen_data);
2267 : : return;
2268 : : case BJ_Metadata:
2269 : 88593 : transaction->t_nr_buffers++;
2270 : 88593 : list = &transaction->t_buffers;
2271 : 88593 : break;
2272 : : case BJ_Forget:
2273 : 52275 : list = &transaction->t_forget;
2274 : 52275 : break;
2275 : : case BJ_Shadow:
2276 : 51713 : list = &transaction->t_shadow_list;
2277 : 51713 : break;
2278 : : case BJ_Reserved:
2279 : 84985 : list = &transaction->t_reserved_list;
2280 : 84985 : break;
2281 : : }
2282 : :
2283 : : __blist_add_buffer(list, jh);
2284 : 277566 : jh->b_jlist = jlist;
2285 : :
2286 [ + + ]: 277566 : if (was_dirty)
2287 : : set_buffer_jbddirty(bh);
2288 : : }
2289 : :
2290 : 0 : void jbd2_journal_file_buffer(struct journal_head *jh,
2291 : : transaction_t *transaction, int jlist)
2292 : : {
2293 : : jbd_lock_bh_state(jh2bh(jh));
2294 : 51713 : spin_lock(&transaction->t_journal->j_list_lock);
2295 : 51713 : __jbd2_journal_file_buffer(jh, transaction, jlist);
2296 : 51713 : spin_unlock(&transaction->t_journal->j_list_lock);
2297 : : jbd_unlock_bh_state(jh2bh(jh));
2298 : 51713 : }
2299 : :
2300 : : /*
2301 : : * Remove a buffer from its current buffer list in preparation for
2302 : : * dropping it from its current transaction entirely. If the buffer has
2303 : : * already started to be used by a subsequent transaction, refile the
2304 : : * buffer on that transaction's metadata list.
2305 : : *
2306 : : * Called under j_list_lock
2307 : : * Called under jbd_lock_bh_state(jh2bh(jh))
2308 : : *
2309 : : * jh and bh may be already free when this function returns
2310 : : */
2311 : 0 : void __jbd2_journal_refile_buffer(struct journal_head *jh)
2312 : : {
2313 : : int was_dirty, jlist;
2314 : : struct buffer_head *bh = jh2bh(jh);
2315 : :
2316 [ - + ]: 52275 : J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2317 [ + - ]: 52275 : if (jh->b_transaction)
2318 [ - + ]: 52275 : assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
2319 : :
2320 : : /* If the buffer is now unused, just drop it. */
2321 [ + + ]: 52275 : if (jh->b_next_transaction == NULL) {
2322 : : __jbd2_journal_unfile_buffer(jh);
2323 : 52275 : return;
2324 : : }
2325 : :
2326 : : /*
2327 : : * It has been modified by a later transaction: add it to the new
2328 : : * transaction's metadata list.
2329 : : */
2330 : :
2331 : : was_dirty = test_clear_buffer_jbddirty(bh);
2332 : 3627 : __jbd2_journal_temp_unlink_buffer(jh);
2333 : : /*
2334 : : * We set b_transaction here because b_next_transaction will inherit
2335 : : * our jh reference and thus __jbd2_journal_file_buffer() must not
2336 : : * take a new one.
2337 : : */
2338 : 3627 : jh->b_transaction = jh->b_next_transaction;
2339 : 3627 : jh->b_next_transaction = NULL;
2340 [ + + ]: 3627 : if (buffer_freed(bh))
2341 : : jlist = BJ_Forget;
2342 [ + + ]: 3622 : else if (jh->b_modified)
2343 : : jlist = BJ_Metadata;
2344 : : else
2345 : : jlist = BJ_Reserved;
2346 : 3627 : __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist);
2347 [ - + ]: 3627 : J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
2348 : :
2349 [ + - ]: 3627 : if (was_dirty)
2350 : : set_buffer_jbddirty(bh);
2351 : : }
2352 : :
2353 : : /*
2354 : : * __jbd2_journal_refile_buffer() with necessary locking added. We take our
2355 : : * bh reference so that we can safely unlock bh.
2356 : : *
2357 : : * The jh and bh may be freed by this call.
2358 : : */
2359 : 0 : void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
2360 : : {
2361 : : struct buffer_head *bh = jh2bh(jh);
2362 : :
2363 : : /* Get reference so that buffer cannot be freed before we unlock it */
2364 : : get_bh(bh);
2365 : : jbd_lock_bh_state(bh);
2366 : : spin_lock(&journal->j_list_lock);
2367 : 0 : __jbd2_journal_refile_buffer(jh);
2368 : : jbd_unlock_bh_state(bh);
2369 : : spin_unlock(&journal->j_list_lock);
2370 : 0 : __brelse(bh);
2371 : 0 : }
2372 : :
2373 : : /*
2374 : : * File inode in the inode list of the handle's transaction
2375 : : */
2376 : 0 : int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
2377 : : {
2378 : 15426 : transaction_t *transaction = handle->h_transaction;
2379 : : journal_t *journal;
2380 : :
2381 [ - + ]: 15426 : WARN_ON(!transaction);
2382 [ + - ]: 15426 : if (is_handle_aborted(handle))
2383 : : return -EROFS;
2384 : 15426 : journal = transaction->t_journal;
2385 : :
2386 : : jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
2387 : : transaction->t_tid);
2388 : :
2389 : : /*
2390 : : * First check whether inode isn't already on the transaction's
2391 : : * lists without taking the lock. Note that this check is safe
2392 : : * without the lock as we cannot race with somebody removing inode
2393 : : * from the transaction. The reason is that we remove inode from the
2394 : : * transaction only in journal_release_jbd_inode() and when we commit
2395 : : * the transaction. We are guarded from the first case by holding
2396 : : * a reference to the inode. We are safe against the second case
2397 : : * because if jinode->i_transaction == transaction, commit code
2398 : : * cannot touch the transaction because we hold reference to it,
2399 : : * and if jinode->i_next_transaction == transaction, commit code
2400 : : * will only file the inode where we want it.
2401 : : */
2402 [ + + ][ + - ]: 15426 : if (jinode->i_transaction == transaction ||
2403 : 1008 : jinode->i_next_transaction == transaction)
2404 : : return 0;
2405 : :
2406 : : spin_lock(&journal->j_list_lock);
2407 : :
2408 [ + - ][ + ]: 1008 : if (jinode->i_transaction == transaction ||
2409 : 1008 : jinode->i_next_transaction == transaction)
2410 : : goto done;
2411 : :
2412 : : /*
2413 : : * We only ever set this variable to 1 so the test is safe. Since
2414 : : * t_need_data_flush is likely to be set, we do the test to save some
2415 : : * cacheline bouncing
2416 : : */
2417 [ + + ]: 16434 : if (!transaction->t_need_data_flush)
2418 : 449 : transaction->t_need_data_flush = 1;
2419 : : /* On some different transaction's list - should be
2420 : : * the committing one */
2421 [ + + ]: 16434 : if (jinode->i_transaction) {
2422 [ - + ]: 8 : J_ASSERT(jinode->i_next_transaction == NULL);
2423 [ - + ]: 8 : J_ASSERT(jinode->i_transaction ==
2424 : : journal->j_committing_transaction);
2425 : 8 : jinode->i_next_transaction = transaction;
2426 : 8 : goto done;
2427 : : }
2428 : : /* Not on any transaction list... */
2429 [ - + ]: 1000 : J_ASSERT(!jinode->i_next_transaction);
2430 : 1000 : jinode->i_transaction = transaction;
2431 : 1000 : list_add(&jinode->i_list, &transaction->t_inode_list);
2432 : : done:
2433 : : spin_unlock(&journal->j_list_lock);
2434 : :
2435 : 1008 : return 0;
2436 : : }
2437 : :
2438 : : /*
2439 : : * File truncate and transaction commit interact with each other in a
2440 : : * non-trivial way. If a transaction writing data block A is
2441 : : * committing, we cannot discard the data by truncate until we have
2442 : : * written them. Otherwise if we crashed after the transaction with
2443 : : * write has committed but before the transaction with truncate has
2444 : : * committed, we could see stale data in block A. This function is a
2445 : : * helper to solve this problem. It starts writeout of the truncated
2446 : : * part in case it is in the committing transaction.
2447 : : *
2448 : : * Filesystem code must call this function when inode is journaled in
2449 : : * ordered mode before truncation happens and after the inode has been
2450 : : * placed on orphan list with the new inode size. The second condition
2451 : : * avoids the race that someone writes new data and we start
2452 : : * committing the transaction after this function has been called but
2453 : : * before a transaction for truncate is started (and furthermore it
2454 : : * allows us to optimize the case where the addition to orphan list
2455 : : * happens in the same transaction as write --- we don't have to write
2456 : : * any data in such case).
2457 : : */
2458 : 0 : int jbd2_journal_begin_ordered_truncate(journal_t *journal,
2459 : : struct jbd2_inode *jinode,
2460 : : loff_t new_size)
2461 : : {
2462 : : transaction_t *inode_trans, *commit_trans;
2463 : : int ret = 0;
2464 : :
2465 : : /* This is a quick check to avoid locking if not necessary */
2466 [ + + ]: 220144 : if (!jinode->i_transaction)
2467 : : goto out;
2468 : : /* Locks are here just to force reading of recent values, it is
2469 : : * enough that the transaction was not committing before we started
2470 : : * a transaction adding the inode to orphan list */
2471 : 17138 : read_lock(&journal->j_state_lock);
2472 : 17138 : commit_trans = journal->j_committing_transaction;
2473 : : read_unlock(&journal->j_state_lock);
2474 : : spin_lock(&journal->j_list_lock);
2475 : 17138 : inode_trans = jinode->i_transaction;
2476 : : spin_unlock(&journal->j_list_lock);
2477 [ + + ]: 17138 : if (inode_trans == commit_trans) {
2478 : 39 : ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping,
2479 : : new_size, LLONG_MAX);
2480 [ - + ]: 39 : if (ret)
2481 : 0 : jbd2_journal_abort(journal, ret);
2482 : : }
2483 : : out:
2484 : 220144 : return ret;
2485 : : }
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