blob: 5f09370c90a8199647a87ef7cb6a5cfdba113d2b [file] [log] [blame]
Dave Kleikamp470decc2006-10-11 01:20:57 -07001/*
Uwe Kleine-König58862692007-05-09 07:51:49 +02002 * linux/fs/jbd2/transaction.c
Dave Kleikamp470decc2006-10-11 01:20:57 -07003 *
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>
Mingming Caof7f4bcc2006-10-11 01:20:59 -070022#include <linux/jbd2.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070023#include <linux/errno.h>
24#include <linux/slab.h>
25#include <linux/timer.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070026#include <linux/mm.h>
27#include <linux/highmem.h>
Josef Bacike07f7182008-11-26 01:14:26 -050028#include <linux/hrtimer.h>
Theodore Ts'o47def822010-07-27 11:56:05 -040029#include <linux/backing-dev.h>
Randy Dunlap44705752011-10-27 04:05:13 -040030#include <linux/bug.h>
Theodore Ts'o47def822010-07-27 11:56:05 -040031#include <linux/module.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070032
Theodore Ts'o343d9c22013-02-08 13:00:22 -050033#include <trace/events/jbd2.h>
34
Adrian Bunk7ddae862006-12-06 20:38:27 -080035static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
Jan Karade1b7942011-06-13 15:38:22 -040036static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
Adrian Bunk7ddae862006-12-06 20:38:27 -080037
Yongqiang Yang0c2022e2012-02-20 17:53:02 -050038static struct kmem_cache *transaction_cache;
39int __init jbd2_journal_init_transaction_cache(void)
40{
41 J_ASSERT(!transaction_cache);
42 transaction_cache = kmem_cache_create("jbd2_transaction_s",
43 sizeof(transaction_t),
44 0,
45 SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
46 NULL);
47 if (transaction_cache)
48 return 0;
49 return -ENOMEM;
50}
51
52void jbd2_journal_destroy_transaction_cache(void)
53{
54 if (transaction_cache) {
55 kmem_cache_destroy(transaction_cache);
56 transaction_cache = NULL;
57 }
58}
59
60void jbd2_journal_free_transaction(transaction_t *transaction)
61{
62 if (unlikely(ZERO_OR_NULL_PTR(transaction)))
63 return;
64 kmem_cache_free(transaction_cache, transaction);
65}
66
Dave Kleikamp470decc2006-10-11 01:20:57 -070067/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -070068 * jbd2_get_transaction: obtain a new transaction_t object.
Dave Kleikamp470decc2006-10-11 01:20:57 -070069 *
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 *
Dave Kleikamp470decc2006-10-11 01:20:57 -070080 */
81
82static transaction_t *
Mingming Caof7f4bcc2006-10-11 01:20:59 -070083jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -070084{
85 transaction->t_journal = journal;
86 transaction->t_state = T_RUNNING;
Josef Bacike07f7182008-11-26 01:14:26 -050087 transaction->t_start_time = ktime_get();
Dave Kleikamp470decc2006-10-11 01:20:57 -070088 transaction->t_tid = journal->j_transaction_sequence++;
89 transaction->t_expires = jiffies + journal->j_commit_interval;
90 spin_lock_init(&transaction->t_handle_lock);
Theodore Ts'oa51dca92010-08-02 08:43:25 -040091 atomic_set(&transaction->t_updates, 0);
Jan Kara8f7d89f2013-06-04 12:35:11 -040092 atomic_set(&transaction->t_outstanding_credits,
93 atomic_read(&journal->j_reserved_credits));
Theodore Ts'o8dd42042010-08-03 21:38:29 -040094 atomic_set(&transaction->t_handle_count, 0);
Jan Karac851ed52008-07-11 19:27:31 -040095 INIT_LIST_HEAD(&transaction->t_inode_list);
Theodore Ts'o3e624fc2008-10-16 20:00:24 -040096 INIT_LIST_HEAD(&transaction->t_private_list);
Dave Kleikamp470decc2006-10-11 01:20:57 -070097
98 /* Set up the commit timer for the new transaction. */
Andreas Dilgerb1f485f2009-08-10 22:51:53 -040099 journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700100 add_timer(&journal->j_commit_timer);
101
102 J_ASSERT(journal->j_running_transaction == NULL);
103 journal->j_running_transaction = transaction;
Johann Lombardi8e85fb32008-01-28 23:58:27 -0500104 transaction->t_max_wait = 0;
105 transaction->t_start = jiffies;
Theodore Ts'o9fff24a2013-02-06 22:30:23 -0500106 transaction->t_requested = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700107
108 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/*
Tao Ma28e35e42011-05-22 21:45:26 -0400120 * Update transaction's maximum wait time, if debugging is enabled.
Theodore Ts'o6d0bf002010-08-09 17:28:38 -0400121 *
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 */
Tao Ma28e35e42011-05-22 21:45:26 -0400129static inline void update_t_max_wait(transaction_t *transaction,
130 unsigned long ts)
Theodore Ts'o6d0bf002010-08-09 17:28:38 -0400131{
132#ifdef CONFIG_JBD2_DEBUG
Theodore Ts'o6d0bf002010-08-09 17:28:38 -0400133 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/*
Jan Kara8f7d89f2013-06-04 12:35:11 -0400145 * 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 */
149static void wait_transaction_locked(journal_t *journal)
150 __releases(journal->j_state_lock)
151{
152 DEFINE_WAIT(wait);
153 int need_to_start;
154 tid_t tid = journal->j_running_transaction->t_tid;
155
156 prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
157 TASK_UNINTERRUPTIBLE);
158 need_to_start = !tid_geq(journal->j_commit_request, tid);
159 read_unlock(&journal->j_state_lock);
160 if (need_to_start)
161 jbd2_log_start_commit(journal, tid);
162 schedule();
163 finish_wait(&journal->j_wait_transaction_locked, &wait);
164}
165
166static void sub_reserved_credits(journal_t *journal, int blocks)
167{
168 atomic_sub(blocks, &journal->j_reserved_credits);
169 wake_up(&journal->j_wait_reserved);
170}
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 */
178static int add_transaction_credits(journal_t *journal, int blocks,
179 int rsv_blocks)
180{
181 transaction_t *t = journal->j_running_transaction;
182 int needed;
183 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 if (t->t_state == T_LOCKED) {
190 wait_transaction_locked(journal);
191 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 needed = atomic_add_return(total, &t->t_outstanding_credits);
200 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 wait_transaction_locked(journal);
208 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 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 write_lock(&journal->j_state_lock);
226 if (jbd2_log_space_left(journal) < jbd2_space_needed(journal))
227 __jbd2_log_wait_for_space(journal);
228 write_unlock(&journal->j_state_lock);
229 return 1;
230 }
231
232 /* No reservation? We are done... */
233 if (!rsv_blocks)
234 return 0;
235
236 needed = atomic_add_return(rsv_blocks, &journal->j_reserved_credits);
237 /* We allow at most half of a transaction to be reserved */
238 if (needed > journal->j_max_transaction_buffers / 2) {
239 sub_reserved_credits(journal, rsv_blocks);
240 atomic_sub(total, &t->t_outstanding_credits);
241 read_unlock(&journal->j_state_lock);
242 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/*
Dave Kleikamp470decc2006-10-11 01:20:57 -0700251 * 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
Theodore Ts'o47def822010-07-27 11:56:05 -0400257static int start_this_handle(journal_t *journal, handle_t *handle,
Dan Carpenterd2159fb2011-09-04 10:20:14 -0400258 gfp_t gfp_mask)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700259{
Theodore Ts'oe4471832011-02-12 08:18:24 -0500260 transaction_t *transaction, *new_transaction = NULL;
Jan Kara8f7d89f2013-06-04 12:35:11 -0400261 int blocks = handle->h_buffer_credits;
262 int rsv_blocks = 0;
Tao Ma28e35e42011-05-22 21:45:26 -0400263 unsigned long ts = jiffies;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700264
Jan Kara8f7d89f2013-06-04 12:35:11 -0400265 /*
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 if (WARN_ON(blocks > journal->j_max_transaction_buffers / 2)) {
Eryu Guanf2a44522011-11-01 19:09:18 -0400270 printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
Jan Kara8f7d89f2013-06-04 12:35:11 -0400271 current->comm, blocks,
272 journal->j_max_transaction_buffers / 2);
Theodore Ts'o47def822010-07-27 11:56:05 -0400273 return -ENOSPC;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700274 }
275
Jan Kara8f7d89f2013-06-04 12:35:11 -0400276 if (handle->h_rsv_handle)
277 rsv_blocks = handle->h_rsv_handle->h_buffer_credits;
278
Dave Kleikamp470decc2006-10-11 01:20:57 -0700279alloc_transaction:
280 if (!journal->j_running_transaction) {
Wanlong Gaob2f4edb2012-06-01 00:10:32 -0400281 new_transaction = kmem_cache_zalloc(transaction_cache,
282 gfp_mask);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700283 if (!new_transaction) {
Theodore Ts'o47def822010-07-27 11:56:05 -0400284 /*
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 if ((gfp_mask & __GFP_FS) == 0) {
292 congestion_wait(BLK_RW_ASYNC, HZ/50);
293 goto alloc_transaction;
294 }
295 return -ENOMEM;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700296 }
Dave Kleikamp470decc2006-10-11 01:20:57 -0700297 }
298
299 jbd_debug(3, "New handle %p going live.\n", handle);
300
Dave Kleikamp470decc2006-10-11 01:20:57 -0700301 /*
302 * We need to hold j_state_lock until t_updates has been incremented,
303 * for proper journal barrier handling
304 */
Theodore Ts'oa931da62010-08-03 21:35:12 -0400305repeat:
306 read_lock(&journal->j_state_lock);
Theodore Ts'o5c2178e2010-10-27 21:30:04 -0400307 BUG_ON(journal->j_flags & JBD2_UNMOUNT);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700308 if (is_journal_aborted(journal) ||
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700309 (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400310 read_unlock(&journal->j_state_lock);
Yongqiang Yang0c2022e2012-02-20 17:53:02 -0500311 jbd2_journal_free_transaction(new_transaction);
Theodore Ts'o47def822010-07-27 11:56:05 -0400312 return -EROFS;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700313 }
314
Jan Kara8f7d89f2013-06-04 12:35:11 -0400315 /*
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 if (!handle->h_reserved && journal->j_barrier_count) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400321 read_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700322 wait_event(journal->j_wait_transaction_locked,
323 journal->j_barrier_count == 0);
324 goto repeat;
325 }
326
327 if (!journal->j_running_transaction) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400328 read_unlock(&journal->j_state_lock);
329 if (!new_transaction)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700330 goto alloc_transaction;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400331 write_lock(&journal->j_state_lock);
Jan Karad7961c72012-12-21 00:15:51 -0500332 if (!journal->j_running_transaction &&
Jan Kara8f7d89f2013-06-04 12:35:11 -0400333 (handle->h_reserved || !journal->j_barrier_count)) {
Theodore Ts'oa931da62010-08-03 21:35:12 -0400334 jbd2_get_transaction(journal, new_transaction);
335 new_transaction = NULL;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700336 }
Theodore Ts'oa931da62010-08-03 21:35:12 -0400337 write_unlock(&journal->j_state_lock);
338 goto repeat;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700339 }
340
341 transaction = journal->j_running_transaction;
342
Jan Kara8f7d89f2013-06-04 12:35:11 -0400343 if (!handle->h_reserved) {
344 /* We may have dropped j_state_lock - restart in that case */
345 if (add_transaction_credits(journal, blocks, rsv_blocks))
346 goto repeat;
347 } else {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700348 /*
Jan Kara8f7d89f2013-06-04 12:35:11 -0400349 * 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.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700352 */
Jan Kara8f7d89f2013-06-04 12:35:11 -0400353 sub_reserved_credits(journal, blocks);
354 handle->h_reserved = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700355 }
356
357 /* OK, account for the buffers that this operation expects to
Theodore Ts'o8dd42042010-08-03 21:38:29 -0400358 * use and add the handle to the running transaction.
Theodore Ts'o8dd42042010-08-03 21:38:29 -0400359 */
Tao Ma28e35e42011-05-22 21:45:26 -0400360 update_t_max_wait(transaction, ts);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700361 handle->h_transaction = transaction;
Jan Kara8f7d89f2013-06-04 12:35:11 -0400362 handle->h_requested_credits = blocks;
Theodore Ts'o343d9c22013-02-08 13:00:22 -0500363 handle->h_start_jiffies = jiffies;
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400364 atomic_inc(&transaction->t_updates);
Theodore Ts'o8dd42042010-08-03 21:38:29 -0400365 atomic_inc(&transaction->t_handle_count);
Jan Kara8f7d89f2013-06-04 12:35:11 -0400366 jbd_debug(4, "Handle %p given %d credits (total %d, free %lu)\n",
367 handle, blocks,
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400368 atomic_read(&transaction->t_outstanding_credits),
Jan Kara76c39902013-06-04 12:12:57 -0400369 jbd2_log_space_left(journal));
Theodore Ts'oa931da62010-08-03 21:35:12 -0400370 read_unlock(&journal->j_state_lock);
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400371 current->journal_info = handle;
Jan Kara9599b0e2009-08-17 21:23:17 -0400372
373 lock_map_acquire(&handle->h_lockdep_map);
Yongqiang Yang0c2022e2012-02-20 17:53:02 -0500374 jbd2_journal_free_transaction(new_transaction);
Theodore Ts'o47def822010-07-27 11:56:05 -0400375 return 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700376}
377
Mingming Cao7b751062008-01-28 23:58:27 -0500378static struct lock_class_key jbd2_handle_key;
379
Dave Kleikamp470decc2006-10-11 01:20:57 -0700380/* Allocate a new handle. This should probably be in a slab... */
381static handle_t *new_handle(int nblocks)
382{
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400383 handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700384 if (!handle)
385 return NULL;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700386 handle->h_buffer_credits = nblocks;
387 handle->h_ref = 1;
388
Mingming Cao7b751062008-01-28 23:58:27 -0500389 lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
390 &jbd2_handle_key, 0);
391
Dave Kleikamp470decc2006-10-11 01:20:57 -0700392 return handle;
393}
394
395/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700396 * handle_t *jbd2_journal_start() - Obtain a new handle.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700397 * @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
Jan Kara8f7d89f2013-06-04 12:35:11 -0400402 * 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.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700410 *
Eryu Guanc8675162011-05-24 17:09:58 -0400411 * Return a pointer to a newly allocated handle, or an ERR_PTR() value
412 * on failure.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700413 */
Jan Kara8f7d89f2013-06-04 12:35:11 -0400414handle_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)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700417{
418 handle_t *handle = journal_current_handle();
419 int err;
420
421 if (!journal)
422 return ERR_PTR(-EROFS);
423
424 if (handle) {
425 J_ASSERT(handle->h_transaction->t_journal == journal);
426 handle->h_ref++;
427 return handle;
428 }
429
430 handle = new_handle(nblocks);
431 if (!handle)
432 return ERR_PTR(-ENOMEM);
Jan Kara8f7d89f2013-06-04 12:35:11 -0400433 if (rsv_blocks) {
434 handle_t *rsv_handle;
435
436 rsv_handle = new_handle(rsv_blocks);
437 if (!rsv_handle) {
438 jbd2_free_handle(handle);
439 return ERR_PTR(-ENOMEM);
440 }
441 rsv_handle->h_reserved = 1;
442 rsv_handle->h_journal = journal;
443 handle->h_rsv_handle = rsv_handle;
444 }
Dave Kleikamp470decc2006-10-11 01:20:57 -0700445
Theodore Ts'o47def822010-07-27 11:56:05 -0400446 err = start_this_handle(journal, handle, gfp_mask);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700447 if (err < 0) {
Jan Kara8f7d89f2013-06-04 12:35:11 -0400448 if (handle->h_rsv_handle)
449 jbd2_free_handle(handle->h_rsv_handle);
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400450 jbd2_free_handle(handle);
Dmitry Monakhovdf05c1b82013-03-02 17:08:46 -0500451 return ERR_PTR(err);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700452 }
Theodore Ts'o343d9c22013-02-08 13:00:22 -0500453 handle->h_type = type;
454 handle->h_line_no = line_no;
455 trace_jbd2_handle_start(journal->j_fs_dev->bd_dev,
456 handle->h_transaction->t_tid, type,
457 line_no, nblocks);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700458 return handle;
459}
Theodore Ts'o47def822010-07-27 11:56:05 -0400460EXPORT_SYMBOL(jbd2__journal_start);
461
462
463handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
464{
Jan Kara8f7d89f2013-06-04 12:35:11 -0400465 return jbd2__journal_start(journal, nblocks, 0, GFP_NOFS, 0, 0);
Theodore Ts'o47def822010-07-27 11:56:05 -0400466}
467EXPORT_SYMBOL(jbd2_journal_start);
468
Jan Kara8f7d89f2013-06-04 12:35:11 -0400469void jbd2_journal_free_reserved(handle_t *handle)
470{
471 journal_t *journal = handle->h_journal;
472
473 WARN_ON(!handle->h_reserved);
474 sub_reserved_credits(journal, handle->h_buffer_credits);
475 jbd2_free_handle(handle);
476}
477EXPORT_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 */
491int jbd2_journal_start_reserved(handle_t *handle, unsigned int type,
492 unsigned int line_no)
493{
494 journal_t *journal = handle->h_journal;
495 int ret = -EIO;
496
497 if (WARN_ON(!handle->h_reserved)) {
498 /* Someone passed in normal handle? Just stop it. */
499 jbd2_journal_stop(handle);
500 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 if (WARN_ON(current->journal_info)) {
507 jbd2_journal_free_reserved(handle);
508 return ret;
509 }
510
511 handle->h_journal = NULL;
Jan Kara8f7d89f2013-06-04 12:35:11 -0400512 /*
513 * GFP_NOFS is here because callers are likely from writeback or
514 * similarly constrained call sites
515 */
516 ret = start_this_handle(journal, handle, GFP_NOFS);
Dan Carpenter92e3b402014-02-17 20:33:01 -0500517 if (ret < 0) {
Jan Kara8f7d89f2013-06-04 12:35:11 -0400518 jbd2_journal_free_reserved(handle);
Dan Carpenter92e3b402014-02-17 20:33:01 -0500519 return ret;
520 }
Jan Kara8f7d89f2013-06-04 12:35:11 -0400521 handle->h_type = type;
522 handle->h_line_no = line_no;
Dan Carpenter92e3b402014-02-17 20:33:01 -0500523 return 0;
Jan Kara8f7d89f2013-06-04 12:35:11 -0400524}
525EXPORT_SYMBOL(jbd2_journal_start_reserved);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700526
527/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700528 * int jbd2_journal_extend() - extend buffer credits.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700529 * @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 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700537 * jbd2_journal_extend tries to give the running handle more buffer credits.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700538 * 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 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700547int jbd2_journal_extend(handle_t *handle, int nblocks)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700548{
549 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400550 journal_t *journal;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700551 int result;
552 int wanted;
553
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400554 WARN_ON(!transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700555 if (is_handle_aborted(handle))
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400556 return -EROFS;
557 journal = transaction->t_journal;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700558
559 result = 1;
560
Theodore Ts'oa931da62010-08-03 21:35:12 -0400561 read_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700562
563 /* Don't extend a locked-down transaction! */
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400564 if (transaction->t_state != T_RUNNING) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700565 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);
Jan Karafe1e8db2013-06-04 12:22:15 -0400571 wanted = atomic_add_return(nblocks,
572 &transaction->t_outstanding_credits);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700573
574 if (wanted > journal->j_max_transaction_buffers) {
575 jbd_debug(3, "denied handle %p %d blocks: "
576 "transaction too large\n", handle, nblocks);
Jan Karafe1e8db2013-06-04 12:22:15 -0400577 atomic_sub(nblocks, &transaction->t_outstanding_credits);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700578 goto unlock;
579 }
580
Jan Kara76c39902013-06-04 12:12:57 -0400581 if (wanted + (wanted >> JBD2_CONTROL_BLOCKS_SHIFT) >
582 jbd2_log_space_left(journal)) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700583 jbd_debug(3, "denied handle %p %d blocks: "
584 "insufficient log space\n", handle, nblocks);
Jan Karafe1e8db2013-06-04 12:22:15 -0400585 atomic_sub(nblocks, &transaction->t_outstanding_credits);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700586 goto unlock;
587 }
588
Theodore Ts'o343d9c22013-02-08 13:00:22 -0500589 trace_jbd2_handle_extend(journal->j_fs_dev->bd_dev,
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400590 transaction->t_tid,
Theodore Ts'o343d9c22013-02-08 13:00:22 -0500591 handle->h_type, handle->h_line_no,
592 handle->h_buffer_credits,
593 nblocks);
594
Dave Kleikamp470decc2006-10-11 01:20:57 -0700595 handle->h_buffer_credits += nblocks;
Theodore Ts'o343d9c22013-02-08 13:00:22 -0500596 handle->h_requested_credits += nblocks;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700597 result = 0;
598
599 jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
600unlock:
601 spin_unlock(&transaction->t_handle_lock);
602error_out:
Theodore Ts'oa931da62010-08-03 21:35:12 -0400603 read_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700604 return result;
605}
606
607
608/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700609 * int jbd2_journal_restart() - restart a handle .
Dave Kleikamp470decc2006-10-11 01:20:57 -0700610 * @handle: handle to restart
611 * @nblocks: nr credits requested
612 *
613 * Restart a handle for a multi-transaction filesystem
614 * operation.
615 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700616 * 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
Dave Kleikamp470decc2006-10-11 01:20:57 -0700618 * handle's transaction so far and reattach the handle to a new
619 * transaction capabable of guaranteeing the requested number of
Jan Kara8f7d89f2013-06-04 12:35:11 -0400620 * credits. We preserve reserved handle if there's any attached to the
621 * passed in handle.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700622 */
Dan Carpenterd2159fb2011-09-04 10:20:14 -0400623int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700624{
625 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400626 journal_t *journal;
Theodore Ts'oe4471832011-02-12 08:18:24 -0500627 tid_t tid;
628 int need_to_start, ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700629
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400630 WARN_ON(!transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700631 /* If we've had an abort of any type, don't even think about
632 * actually doing the restart! */
633 if (is_handle_aborted(handle))
634 return 0;
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400635 journal = transaction->t_journal;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700636
637 /*
638 * First unlink the handle from its current transaction, and start the
639 * commit on that.
640 */
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400641 J_ASSERT(atomic_read(&transaction->t_updates) > 0);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700642 J_ASSERT(journal_current_handle() == handle);
643
Theodore Ts'oa931da62010-08-03 21:35:12 -0400644 read_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700645 spin_lock(&transaction->t_handle_lock);
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400646 atomic_sub(handle->h_buffer_credits,
647 &transaction->t_outstanding_credits);
Jan Kara8f7d89f2013-06-04 12:35:11 -0400648 if (handle->h_rsv_handle) {
649 sub_reserved_credits(journal,
650 handle->h_rsv_handle->h_buffer_credits);
651 }
Theodore Ts'oa51dca92010-08-02 08:43:25 -0400652 if (atomic_dec_and_test(&transaction->t_updates))
Dave Kleikamp470decc2006-10-11 01:20:57 -0700653 wake_up(&journal->j_wait_updates);
Theodore Ts'o39c04152013-07-01 08:12:40 -0400654 tid = transaction->t_tid;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700655 spin_unlock(&transaction->t_handle_lock);
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400656 handle->h_transaction = NULL;
657 current->journal_info = NULL;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700658
659 jbd_debug(2, "restarting handle %p\n", handle);
Theodore Ts'oe4471832011-02-12 08:18:24 -0500660 need_to_start = !tid_geq(journal->j_commit_request, tid);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400661 read_unlock(&journal->j_state_lock);
Theodore Ts'oe4471832011-02-12 08:18:24 -0500662 if (need_to_start)
663 jbd2_log_start_commit(journal, tid);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700664
Jan Kara9599b0e2009-08-17 21:23:17 -0400665 lock_map_release(&handle->h_lockdep_map);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700666 handle->h_buffer_credits = nblocks;
Theodore Ts'o47def822010-07-27 11:56:05 -0400667 ret = start_this_handle(journal, handle, gfp_mask);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700668 return ret;
669}
Theodore Ts'o47def822010-07-27 11:56:05 -0400670EXPORT_SYMBOL(jbd2__journal_restart);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700671
672
Theodore Ts'o47def822010-07-27 11:56:05 -0400673int jbd2_journal_restart(handle_t *handle, int nblocks)
674{
675 return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
676}
677EXPORT_SYMBOL(jbd2_journal_restart);
678
Dave Kleikamp470decc2006-10-11 01:20:57 -0700679/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700680 * void jbd2_journal_lock_updates () - establish a transaction barrier.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700681 * @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 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700689void jbd2_journal_lock_updates(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700690{
691 DEFINE_WAIT(wait);
692
Theodore Ts'oa931da62010-08-03 21:35:12 -0400693 write_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700694 ++journal->j_barrier_count;
695
Jan Kara8f7d89f2013-06-04 12:35:11 -0400696 /* Wait until there are no reserved handles */
697 if (atomic_read(&journal->j_reserved_credits)) {
698 write_unlock(&journal->j_state_lock);
699 wait_event(journal->j_wait_reserved,
700 atomic_read(&journal->j_reserved_credits) == 0);
701 write_lock(&journal->j_state_lock);
702 }
703
Dave Kleikamp470decc2006-10-11 01:20:57 -0700704 /* Wait until there are no running updates */
705 while (1) {
706 transaction_t *transaction = journal->j_running_transaction;
707
708 if (!transaction)
709 break;
710
711 spin_lock(&transaction->t_handle_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700712 prepare_to_wait(&journal->j_wait_updates, &wait,
713 TASK_UNINTERRUPTIBLE);
Jan Kara9837d8e2012-01-04 22:03:11 -0500714 if (!atomic_read(&transaction->t_updates)) {
715 spin_unlock(&transaction->t_handle_lock);
716 finish_wait(&journal->j_wait_updates, &wait);
717 break;
718 }
Dave Kleikamp470decc2006-10-11 01:20:57 -0700719 spin_unlock(&transaction->t_handle_lock);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400720 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700721 schedule();
722 finish_wait(&journal->j_wait_updates, &wait);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400723 write_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700724 }
Theodore Ts'oa931da62010-08-03 21:35:12 -0400725 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700726
727 /*
728 * We have now established a barrier against other normal updates, but
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700729 * we also need to barrier against other jbd2_journal_lock_updates() calls
Dave Kleikamp470decc2006-10-11 01:20:57 -0700730 * to make sure that we serialise special journal-locked operations
731 * too.
732 */
733 mutex_lock(&journal->j_barrier);
734}
735
736/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700737 * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier
Dave Kleikamp470decc2006-10-11 01:20:57 -0700738 * @journal: Journal to release the barrier on.
739 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700740 * Release a transaction barrier obtained with jbd2_journal_lock_updates().
Dave Kleikamp470decc2006-10-11 01:20:57 -0700741 *
742 * Should be called without the journal lock held.
743 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700744void jbd2_journal_unlock_updates (journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700745{
746 J_ASSERT(journal->j_barrier_count != 0);
747
748 mutex_unlock(&journal->j_barrier);
Theodore Ts'oa931da62010-08-03 21:35:12 -0400749 write_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700750 --journal->j_barrier_count;
Theodore Ts'oa931da62010-08-03 21:35:12 -0400751 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700752 wake_up(&journal->j_wait_transaction_locked);
753}
754
Jan Karaf91d1d02009-07-13 16:16:20 -0400755static void warn_dirty_buffer(struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700756{
Jan Karaf91d1d02009-07-13 16:16:20 -0400757 char b[BDEVNAME_SIZE];
Dave Kleikamp470decc2006-10-11 01:20:57 -0700758
Jan Karaf91d1d02009-07-13 16:16:20 -0400759 printk(KERN_WARNING
Eryu Guanf2a44522011-11-01 19:09:18 -0400760 "JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
Jan Karaf91d1d02009-07-13 16:16:20 -0400761 "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);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700764}
765
766/*
767 * If the buffer is already part of the current transaction, then there
768 * is nothing we need to do. If it is already part of a prior
769 * transaction which we are still committing to disk, then we need to
770 * make sure that we do not overwrite the old copy: we do copy-out to
771 * preserve the copy going to disk. We also account the buffer against
772 * the handle's metadata buffer credits (unless the buffer is already
773 * part of the transaction, that is).
774 *
775 */
776static int
777do_get_write_access(handle_t *handle, struct journal_head *jh,
778 int force_copy)
779{
780 struct buffer_head *bh;
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400781 transaction_t *transaction = handle->h_transaction;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700782 journal_t *journal;
783 int error;
784 char *frozen_buffer = NULL;
785 int need_copy = 0;
Theodore Ts'of783f092013-04-21 16:47:54 -0400786 unsigned long start_lock, time_lock;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700787
Theodore Ts'o41a5b912013-07-01 08:12:41 -0400788 WARN_ON(!transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700789 if (is_handle_aborted(handle))
790 return -EROFS;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700791 journal = transaction->t_journal;
792
Theodore Ts'ocfef2c62010-12-18 13:07:34 -0500793 jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700794
795 JBUFFER_TRACE(jh, "entry");
796repeat:
797 bh = jh2bh(jh);
798
799 /* @@@ Need to check for errors here at some point. */
800
Theodore Ts'of783f092013-04-21 16:47:54 -0400801 start_lock = jiffies;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700802 lock_buffer(bh);
803 jbd_lock_bh_state(bh);
804
Theodore Ts'of783f092013-04-21 16:47:54 -0400805 /* If it takes too long to lock the buffer, trace it */
806 time_lock = jbd2_time_diff(start_lock, jiffies);
807 if (time_lock > HZ/10)
808 trace_jbd2_lock_buffer_stall(bh->b_bdev->bd_dev,
809 jiffies_to_msecs(time_lock));
810
Dave Kleikamp470decc2006-10-11 01:20:57 -0700811 /* We now hold the buffer lock so it is safe to query the buffer
812 * state. Is the buffer dirty?
813 *
814 * If so, there are two possibilities. The buffer may be
815 * non-journaled, and undergoing a quite legitimate writeback.
816 * Otherwise, it is journaled, and we don't expect dirty buffers
817 * in that state (the buffers should be marked JBD_Dirty
818 * instead.) So either the IO is being done under our own
819 * control and this is a bug, or it's a third party IO such as
820 * dump(8) (which may leave the buffer scheduled for read ---
821 * ie. locked but not dirty) or tune2fs (which may actually have
822 * the buffer dirtied, ugh.) */
823
824 if (buffer_dirty(bh)) {
825 /*
826 * First question: is this buffer already part of the current
827 * transaction or the existing committing transaction?
828 */
829 if (jh->b_transaction) {
830 J_ASSERT_JH(jh,
831 jh->b_transaction == transaction ||
832 jh->b_transaction ==
833 journal->j_committing_transaction);
834 if (jh->b_next_transaction)
835 J_ASSERT_JH(jh, jh->b_next_transaction ==
836 transaction);
Jan Karaf91d1d02009-07-13 16:16:20 -0400837 warn_dirty_buffer(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700838 }
839 /*
840 * In any case we need to clean the dirty flag and we must
841 * do it under the buffer lock to be sure we don't race
842 * with running write-out.
843 */
Jan Karaf91d1d02009-07-13 16:16:20 -0400844 JBUFFER_TRACE(jh, "Journalling dirty buffer");
845 clear_buffer_dirty(bh);
846 set_buffer_jbddirty(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700847 }
848
849 unlock_buffer(bh);
850
851 error = -EROFS;
852 if (is_handle_aborted(handle)) {
853 jbd_unlock_bh_state(bh);
854 goto out;
855 }
856 error = 0;
857
858 /*
859 * The buffer is already part of this transaction if b_transaction or
860 * b_next_transaction points to it
861 */
862 if (jh->b_transaction == transaction ||
863 jh->b_next_transaction == transaction)
864 goto done;
865
866 /*
Josef Bacik9fc7c632008-04-17 10:38:59 -0400867 * this is the first time this transaction is touching this buffer,
868 * reset the modified flag
869 */
870 jh->b_modified = 0;
871
872 /*
Dave Kleikamp470decc2006-10-11 01:20:57 -0700873 * If there is already a copy-out version of this buffer, then we don't
874 * need to make another one
875 */
876 if (jh->b_frozen_data) {
877 JBUFFER_TRACE(jh, "has frozen data");
878 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
879 jh->b_next_transaction = transaction;
880 goto done;
881 }
882
883 /* Is there data here we need to preserve? */
884
885 if (jh->b_transaction && jh->b_transaction != transaction) {
886 JBUFFER_TRACE(jh, "owned by older transaction");
887 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
888 J_ASSERT_JH(jh, jh->b_transaction ==
889 journal->j_committing_transaction);
890
891 /* There is one case we have to be very careful about.
892 * If the committing transaction is currently writing
893 * this buffer out to disk and has NOT made a copy-out,
894 * then we cannot modify the buffer contents at all
895 * right now. The essence of copy-out is that it is the
896 * extra copy, not the primary copy, which gets
897 * journaled. If the primary copy is already going to
898 * disk then we cannot do copy-out here. */
899
Jan Karab34090e2013-06-04 12:08:56 -0400900 if (buffer_shadow(bh)) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700901 JBUFFER_TRACE(jh, "on shadow: sleep");
902 jbd_unlock_bh_state(bh);
NeilBrown74316202014-07-07 15:16:04 +1000903 wait_on_bit_io(&bh->b_state, BH_Shadow,
904 TASK_UNINTERRUPTIBLE);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700905 goto repeat;
906 }
907
Jan Karab34090e2013-06-04 12:08:56 -0400908 /*
909 * Only do the copy if the currently-owning transaction still
910 * needs it. If buffer isn't on BJ_Metadata list, the
911 * committing transaction is past that stage (here we use the
912 * fact that BH_Shadow is set under bh_state lock together with
913 * refiling to BJ_Shadow list and at this point we know the
914 * buffer doesn't have BH_Shadow set).
Dave Kleikamp470decc2006-10-11 01:20:57 -0700915 *
916 * Subtle point, though: if this is a get_undo_access,
917 * then we will be relying on the frozen_data to contain
918 * the new value of the committed_data record after the
919 * transaction, so we HAVE to force the frozen_data copy
Jan Karab34090e2013-06-04 12:08:56 -0400920 * in that case.
921 */
922 if (jh->b_jlist == BJ_Metadata || force_copy) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700923 JBUFFER_TRACE(jh, "generate frozen data");
924 if (!frozen_buffer) {
925 JBUFFER_TRACE(jh, "allocate memory for buffer");
926 jbd_unlock_bh_state(bh);
927 frozen_buffer =
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400928 jbd2_alloc(jh2bh(jh)->b_size,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700929 GFP_NOFS);
930 if (!frozen_buffer) {
Jan Kara75685072013-12-08 21:13:59 -0500931 printk(KERN_ERR
Dave Kleikamp470decc2006-10-11 01:20:57 -0700932 "%s: OOM for frozen_buffer\n",
Harvey Harrison329d2912008-04-17 10:38:59 -0400933 __func__);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700934 JBUFFER_TRACE(jh, "oom!");
935 error = -ENOMEM;
936 jbd_lock_bh_state(bh);
937 goto done;
938 }
939 goto repeat;
940 }
941 jh->b_frozen_data = frozen_buffer;
942 frozen_buffer = NULL;
943 need_copy = 1;
944 }
945 jh->b_next_transaction = transaction;
946 }
947
948
949 /*
950 * Finally, if the buffer is not journaled right now, we need to make
951 * sure it doesn't get written to disk before the caller actually
952 * commits the new data
953 */
954 if (!jh->b_transaction) {
955 JBUFFER_TRACE(jh, "no transaction");
956 J_ASSERT_JH(jh, !jh->b_next_transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700957 JBUFFER_TRACE(jh, "file as BJ_Reserved");
958 spin_lock(&journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700959 __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700960 spin_unlock(&journal->j_list_lock);
961 }
962
963done:
964 if (need_copy) {
965 struct page *page;
966 int offset;
967 char *source;
968
969 J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)),
970 "Possible IO failure.\n");
971 page = jh2bh(jh)->b_page;
Theodore Ts'oa1dd5332010-12-18 13:13:40 -0500972 offset = offset_in_page(jh2bh(jh)->b_data);
Cong Wang303a8f22011-11-25 23:14:31 +0800973 source = kmap_atomic(page);
Jan Kara13ceef02010-07-14 07:56:33 +0200974 /* Fire data frozen trigger just before we copy the data */
975 jbd2_buffer_frozen_trigger(jh, source + offset,
976 jh->b_triggers);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700977 memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
Cong Wang303a8f22011-11-25 23:14:31 +0800978 kunmap_atomic(source);
Joel Beckere06c8222008-09-11 15:35:47 -0700979
980 /*
981 * Now that the frozen data is saved off, we need to store
982 * any matching triggers.
983 */
984 jh->b_frozen_triggers = jh->b_triggers;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700985 }
986 jbd_unlock_bh_state(bh);
987
988 /*
989 * If we are about to journal a buffer, then any revoke pending on it is
990 * no longer valid
991 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700992 jbd2_journal_cancel_revoke(handle, jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700993
994out:
995 if (unlikely(frozen_buffer)) /* It's usually NULL */
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400996 jbd2_free(frozen_buffer, bh->b_size);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700997
998 JBUFFER_TRACE(jh, "exit");
999 return error;
1000}
1001
1002/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001003 * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001004 * @handle: transaction to add buffer modifications to
1005 * @bh: bh to be used for metadata writes
Dave Kleikamp470decc2006-10-11 01:20:57 -07001006 *
1007 * Returns an error code or 0 on success.
1008 *
1009 * In full data journalling mode the buffer may be of type BJ_AsyncData,
1010 * because we're write()ing a buffer which is also part of a shared mapping.
1011 */
1012
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001013int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001014{
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001015 struct journal_head *jh = jbd2_journal_add_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001016 int rc;
1017
1018 /* We do not want to get caught playing with fields which the
1019 * log thread also manipulates. Make sure that the buffer
1020 * completes any outstanding IO before proceeding. */
1021 rc = do_get_write_access(handle, jh, 0);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001022 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001023 return rc;
1024}
1025
1026
1027/*
1028 * When the user wants to journal a newly created buffer_head
1029 * (ie. getblk() returned a new buffer and we are going to populate it
1030 * manually rather than reading off disk), then we need to keep the
1031 * buffer_head locked until it has been completely filled with new
1032 * data. In this case, we should be able to make the assertion that
1033 * the bh is not already part of an existing transaction.
1034 *
1035 * The buffer should already be locked by the caller by this point.
1036 * There is no lock ranking violation: it was a newly created,
1037 * unlocked buffer beforehand. */
1038
1039/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001040 * int jbd2_journal_get_create_access () - notify intent to use newly created bh
Dave Kleikamp470decc2006-10-11 01:20:57 -07001041 * @handle: transaction to new buffer to
1042 * @bh: new buffer.
1043 *
1044 * Call this if you create a new bh.
1045 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001046int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001047{
1048 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001049 journal_t *journal;
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001050 struct journal_head *jh = jbd2_journal_add_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001051 int err;
1052
1053 jbd_debug(5, "journal_head %p\n", jh);
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001054 WARN_ON(!transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001055 err = -EROFS;
1056 if (is_handle_aborted(handle))
1057 goto out;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001058 journal = transaction->t_journal;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001059 err = 0;
1060
1061 JBUFFER_TRACE(jh, "entry");
1062 /*
1063 * The buffer may already belong to this transaction due to pre-zeroing
1064 * in the filesystem's new_block code. It may also be on the previous,
1065 * committing transaction's lists, but it HAS to be in Forget state in
1066 * that case: the transaction must have deleted the buffer for it to be
1067 * reused here.
1068 */
1069 jbd_lock_bh_state(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001070 J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
1071 jh->b_transaction == NULL ||
1072 (jh->b_transaction == journal->j_committing_transaction &&
1073 jh->b_jlist == BJ_Forget)));
1074
1075 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
1076 J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
1077
1078 if (jh->b_transaction == NULL) {
Jan Karaf91d1d02009-07-13 16:16:20 -04001079 /*
1080 * Previous jbd2_journal_forget() could have left the buffer
1081 * with jbddirty bit set because it was being committed. When
1082 * the commit finished, we've filed the buffer for
1083 * checkpointing and marked it dirty. Now we are reallocating
1084 * the buffer so the transaction freeing it must have
1085 * committed and so it's safe to clear the dirty bit.
1086 */
1087 clear_buffer_dirty(jh2bh(jh));
Josef Bacik9fc7c632008-04-17 10:38:59 -04001088 /* first access by this transaction */
1089 jh->b_modified = 0;
1090
Dave Kleikamp470decc2006-10-11 01:20:57 -07001091 JBUFFER_TRACE(jh, "file as BJ_Reserved");
Theodore Ts'o6e4862a2014-03-09 00:46:23 -05001092 spin_lock(&journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001093 __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001094 } else if (jh->b_transaction == journal->j_committing_transaction) {
Josef Bacik9fc7c632008-04-17 10:38:59 -04001095 /* first access by this transaction */
1096 jh->b_modified = 0;
1097
Dave Kleikamp470decc2006-10-11 01:20:57 -07001098 JBUFFER_TRACE(jh, "set next transaction");
Theodore Ts'o6e4862a2014-03-09 00:46:23 -05001099 spin_lock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001100 jh->b_next_transaction = transaction;
1101 }
1102 spin_unlock(&journal->j_list_lock);
1103 jbd_unlock_bh_state(bh);
1104
1105 /*
1106 * akpm: I added this. ext3_alloc_branch can pick up new indirect
1107 * blocks which contain freed but then revoked metadata. We need
1108 * to cancel the revoke in case we end up freeing it yet again
1109 * and the reallocating as data - this would cause a second revoke,
1110 * which hits an assertion error.
1111 */
1112 JBUFFER_TRACE(jh, "cancelling revoke");
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001113 jbd2_journal_cancel_revoke(handle, jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001114out:
Ding Dinghua3991b402011-05-25 17:43:48 -04001115 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001116 return err;
1117}
1118
1119/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001120 * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with
Dave Kleikamp470decc2006-10-11 01:20:57 -07001121 * non-rewindable consequences
1122 * @handle: transaction
1123 * @bh: buffer to undo
Dave Kleikamp470decc2006-10-11 01:20:57 -07001124 *
1125 * Sometimes there is a need to distinguish between metadata which has
1126 * been committed to disk and that which has not. The ext3fs code uses
1127 * this for freeing and allocating space, we have to make sure that we
1128 * do not reuse freed space until the deallocation has been committed,
1129 * since if we overwrote that space we would make the delete
1130 * un-rewindable in case of a crash.
1131 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001132 * To deal with that, jbd2_journal_get_undo_access requests write access to a
Dave Kleikamp470decc2006-10-11 01:20:57 -07001133 * buffer for parts of non-rewindable operations such as delete
1134 * operations on the bitmaps. The journaling code must keep a copy of
1135 * the buffer's contents prior to the undo_access call until such time
1136 * as we know that the buffer has definitely been committed to disk.
1137 *
1138 * We never need to know which transaction the committed data is part
1139 * of, buffers touched here are guaranteed to be dirtied later and so
1140 * will be committed to a new transaction in due course, at which point
1141 * we can discard the old committed data pointer.
1142 *
1143 * Returns error number or 0 on success.
1144 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001145int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001146{
1147 int err;
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001148 struct journal_head *jh = jbd2_journal_add_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001149 char *committed_data = NULL;
1150
1151 JBUFFER_TRACE(jh, "entry");
1152
1153 /*
1154 * Do this first --- it can drop the journal lock, so we want to
1155 * make sure that obtaining the committed_data is done
1156 * atomically wrt. completion of any outstanding commits.
1157 */
1158 err = do_get_write_access(handle, jh, 1);
1159 if (err)
1160 goto out;
1161
1162repeat:
1163 if (!jh->b_committed_data) {
Mingming Caoaf1e76d2007-10-16 18:38:25 -04001164 committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001165 if (!committed_data) {
Jan Kara75685072013-12-08 21:13:59 -05001166 printk(KERN_ERR "%s: No memory for committed data\n",
Harvey Harrison329d2912008-04-17 10:38:59 -04001167 __func__);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001168 err = -ENOMEM;
1169 goto out;
1170 }
1171 }
1172
1173 jbd_lock_bh_state(bh);
1174 if (!jh->b_committed_data) {
1175 /* Copy out the current buffer contents into the
1176 * preserved, committed copy. */
1177 JBUFFER_TRACE(jh, "generate b_committed data");
1178 if (!committed_data) {
1179 jbd_unlock_bh_state(bh);
1180 goto repeat;
1181 }
1182
1183 jh->b_committed_data = committed_data;
1184 committed_data = NULL;
1185 memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
1186 }
1187 jbd_unlock_bh_state(bh);
1188out:
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001189 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001190 if (unlikely(committed_data))
Mingming Caoaf1e76d2007-10-16 18:38:25 -04001191 jbd2_free(committed_data, bh->b_size);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001192 return err;
1193}
1194
1195/**
Joel Beckere06c8222008-09-11 15:35:47 -07001196 * void jbd2_journal_set_triggers() - Add triggers for commit writeout
1197 * @bh: buffer to trigger on
1198 * @type: struct jbd2_buffer_trigger_type containing the trigger(s).
1199 *
1200 * Set any triggers on this journal_head. This is always safe, because
1201 * triggers for a committing buffer will be saved off, and triggers for
1202 * a running transaction will match the buffer in that transaction.
1203 *
1204 * Call with NULL to clear the triggers.
1205 */
1206void jbd2_journal_set_triggers(struct buffer_head *bh,
1207 struct jbd2_buffer_trigger_type *type)
1208{
Jan Karaad56eda2013-03-11 13:24:56 -04001209 struct journal_head *jh = jbd2_journal_grab_journal_head(bh);
Joel Beckere06c8222008-09-11 15:35:47 -07001210
Jan Karaad56eda2013-03-11 13:24:56 -04001211 if (WARN_ON(!jh))
1212 return;
Joel Beckere06c8222008-09-11 15:35:47 -07001213 jh->b_triggers = type;
Jan Karaad56eda2013-03-11 13:24:56 -04001214 jbd2_journal_put_journal_head(jh);
Joel Beckere06c8222008-09-11 15:35:47 -07001215}
1216
Jan Kara13ceef02010-07-14 07:56:33 +02001217void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
Joel Beckere06c8222008-09-11 15:35:47 -07001218 struct jbd2_buffer_trigger_type *triggers)
1219{
1220 struct buffer_head *bh = jh2bh(jh);
1221
Jan Kara13ceef02010-07-14 07:56:33 +02001222 if (!triggers || !triggers->t_frozen)
Joel Beckere06c8222008-09-11 15:35:47 -07001223 return;
1224
Jan Kara13ceef02010-07-14 07:56:33 +02001225 triggers->t_frozen(triggers, bh, mapped_data, bh->b_size);
Joel Beckere06c8222008-09-11 15:35:47 -07001226}
1227
1228void jbd2_buffer_abort_trigger(struct journal_head *jh,
1229 struct jbd2_buffer_trigger_type *triggers)
1230{
1231 if (!triggers || !triggers->t_abort)
1232 return;
1233
1234 triggers->t_abort(triggers, jh2bh(jh));
1235}
1236
1237
1238
1239/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001240 * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata
Dave Kleikamp470decc2006-10-11 01:20:57 -07001241 * @handle: transaction to add buffer to.
1242 * @bh: buffer to mark
1243 *
1244 * mark dirty metadata which needs to be journaled as part of the current
1245 * transaction.
1246 *
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001247 * The buffer must have previously had jbd2_journal_get_write_access()
1248 * called so that it has a valid journal_head attached to the buffer
1249 * head.
1250 *
Dave Kleikamp470decc2006-10-11 01:20:57 -07001251 * The buffer is placed on the transaction's metadata list and is marked
1252 * as belonging to the transaction.
1253 *
1254 * Returns error number or 0 on success.
1255 *
1256 * Special care needs to be taken if the buffer already belongs to the
1257 * current committing transaction (in which case we should have frozen
1258 * data present for that commit). In that case, we don't relink the
1259 * buffer: that only gets done when the old transaction finally
1260 * completes its commit.
1261 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001262int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001263{
1264 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001265 journal_t *journal;
Jan Karaad56eda2013-03-11 13:24:56 -04001266 struct journal_head *jh;
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001267 int ret = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001268
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001269 WARN_ON(!transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001270 if (is_handle_aborted(handle))
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001271 return -EROFS;
1272 journal = transaction->t_journal;
Jan Karaad56eda2013-03-11 13:24:56 -04001273 jh = jbd2_journal_grab_journal_head(bh);
1274 if (!jh) {
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001275 ret = -EUCLEAN;
1276 goto out;
1277 }
Jan Karaad56eda2013-03-11 13:24:56 -04001278 jbd_debug(5, "journal_head %p\n", jh);
1279 JBUFFER_TRACE(jh, "entry");
Dave Kleikamp470decc2006-10-11 01:20:57 -07001280
1281 jbd_lock_bh_state(bh);
1282
1283 if (jh->b_modified == 0) {
1284 /*
1285 * This buffer's got modified and becoming part
1286 * of the transaction. This needs to be done
1287 * once a transaction -bzzz
1288 */
1289 jh->b_modified = 1;
Theodore Ts'of6c07ca2013-12-08 21:12:59 -05001290 if (handle->h_buffer_credits <= 0) {
1291 ret = -ENOSPC;
1292 goto out_unlock_bh;
1293 }
Dave Kleikamp470decc2006-10-11 01:20:57 -07001294 handle->h_buffer_credits--;
1295 }
1296
1297 /*
1298 * fastpath, to avoid expensive locking. If this buffer is already
1299 * on the running transaction's metadata list there is nothing to do.
1300 * Nobody can take it off again because there is a handle open.
1301 * I _think_ we're OK here with SMP barriers - a mistaken decision will
1302 * result in this test being false, so we go in and take the locks.
1303 */
1304 if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
1305 JBUFFER_TRACE(jh, "fastpath");
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001306 if (unlikely(jh->b_transaction !=
1307 journal->j_running_transaction)) {
Dmitry Monakhova67c8482013-12-08 21:14:59 -05001308 printk(KERN_ERR "JBD2: %s: "
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001309 "jh->b_transaction (%llu, %p, %u) != "
Theodore Ts'o66a4cb12014-03-12 16:38:03 -04001310 "journal->j_running_transaction (%p, %u)\n",
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001311 journal->j_devname,
1312 (unsigned long long) bh->b_blocknr,
1313 jh->b_transaction,
1314 jh->b_transaction ? jh->b_transaction->t_tid : 0,
1315 journal->j_running_transaction,
1316 journal->j_running_transaction ?
1317 journal->j_running_transaction->t_tid : 0);
1318 ret = -EINVAL;
1319 }
Dave Kleikamp470decc2006-10-11 01:20:57 -07001320 goto out_unlock_bh;
1321 }
1322
1323 set_buffer_jbddirty(bh);
1324
1325 /*
1326 * Metadata already on the current transaction list doesn't
1327 * need to be filed. Metadata on another transaction's list must
1328 * be committing, and will be refiled once the commit completes:
1329 * leave it alone for now.
1330 */
1331 if (jh->b_transaction != transaction) {
1332 JBUFFER_TRACE(jh, "already on other transaction");
Theodore Ts'o66a4cb12014-03-12 16:38:03 -04001333 if (unlikely(((jh->b_transaction !=
1334 journal->j_committing_transaction)) ||
1335 (jh->b_next_transaction != transaction))) {
1336 printk(KERN_ERR "jbd2_journal_dirty_metadata: %s: "
1337 "bad jh for block %llu: "
1338 "transaction (%p, %u), "
1339 "jh->b_transaction (%p, %u), "
1340 "jh->b_next_transaction (%p, %u), jlist %u\n",
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001341 journal->j_devname,
1342 (unsigned long long) bh->b_blocknr,
Theodore Ts'o66a4cb12014-03-12 16:38:03 -04001343 transaction, transaction->t_tid,
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001344 jh->b_transaction,
Theodore Ts'o66a4cb12014-03-12 16:38:03 -04001345 jh->b_transaction ?
1346 jh->b_transaction->t_tid : 0,
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001347 jh->b_next_transaction,
1348 jh->b_next_transaction ?
1349 jh->b_next_transaction->t_tid : 0,
Theodore Ts'o66a4cb12014-03-12 16:38:03 -04001350 jh->b_jlist);
1351 WARN_ON(1);
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001352 ret = -EINVAL;
1353 }
Dave Kleikamp470decc2006-10-11 01:20:57 -07001354 /* And this case is illegal: we can't reuse another
1355 * transaction's data buffer, ever. */
1356 goto out_unlock_bh;
1357 }
1358
1359 /* That test should have eliminated the following case: */
Mingming Cao40191912008-01-28 23:58:27 -05001360 J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001361
1362 JBUFFER_TRACE(jh, "file as BJ_Metadata");
1363 spin_lock(&journal->j_list_lock);
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001364 __jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001365 spin_unlock(&journal->j_list_lock);
1366out_unlock_bh:
1367 jbd_unlock_bh_state(bh);
Jan Karaad56eda2013-03-11 13:24:56 -04001368 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001369out:
1370 JBUFFER_TRACE(jh, "exit");
Theodore Ts'o9ea7a0d2011-09-04 10:18:14 -04001371 return ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001372}
1373
Dave Kleikamp470decc2006-10-11 01:20:57 -07001374/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001375 * void jbd2_journal_forget() - bforget() for potentially-journaled buffers.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001376 * @handle: transaction handle
1377 * @bh: bh to 'forget'
1378 *
1379 * We can only do the bforget if there are no commits pending against the
1380 * buffer. If the buffer is dirty in the current running transaction we
1381 * can safely unlink it.
1382 *
1383 * bh may not be a journalled buffer at all - it may be a non-JBD
1384 * buffer which came off the hashtable. Check for this.
1385 *
1386 * Decrements bh->b_count by one.
1387 *
1388 * Allow this call even if the handle has aborted --- it may be part of
1389 * the caller's cleanup after an abort.
1390 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001391int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001392{
1393 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001394 journal_t *journal;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001395 struct journal_head *jh;
1396 int drop_reserve = 0;
1397 int err = 0;
Josef Bacik1dfc3222008-04-17 10:38:59 -04001398 int was_modified = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001399
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001400 WARN_ON(!transaction);
1401 if (is_handle_aborted(handle))
1402 return -EROFS;
1403 journal = transaction->t_journal;
1404
Dave Kleikamp470decc2006-10-11 01:20:57 -07001405 BUFFER_TRACE(bh, "entry");
1406
1407 jbd_lock_bh_state(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001408
1409 if (!buffer_jbd(bh))
1410 goto not_jbd;
1411 jh = bh2jh(bh);
1412
1413 /* Critical error: attempting to delete a bitmap buffer, maybe?
1414 * Don't do any jbd operations, and return an error. */
1415 if (!J_EXPECT_JH(jh, !jh->b_committed_data,
1416 "inconsistent data on disk")) {
1417 err = -EIO;
1418 goto not_jbd;
1419 }
1420
Adam Buchbinder48fc7f72012-09-19 21:48:00 -04001421 /* keep track of whether or not this transaction modified us */
Josef Bacik1dfc3222008-04-17 10:38:59 -04001422 was_modified = jh->b_modified;
1423
Dave Kleikamp470decc2006-10-11 01:20:57 -07001424 /*
1425 * The buffer's going from the transaction, we must drop
1426 * all references -bzzz
1427 */
1428 jh->b_modified = 0;
1429
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001430 if (jh->b_transaction == transaction) {
Dave Kleikamp470decc2006-10-11 01:20:57 -07001431 J_ASSERT_JH(jh, !jh->b_frozen_data);
1432
1433 /* If we are forgetting a buffer which is already part
1434 * of this transaction, then we can just drop it from
1435 * the transaction immediately. */
1436 clear_buffer_dirty(bh);
1437 clear_buffer_jbddirty(bh);
1438
1439 JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
1440
Josef Bacik1dfc3222008-04-17 10:38:59 -04001441 /*
1442 * we only want to drop a reference if this transaction
1443 * modified the buffer
1444 */
1445 if (was_modified)
1446 drop_reserve = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001447
1448 /*
1449 * We are no longer going to journal this buffer.
1450 * However, the commit of this transaction is still
1451 * important to the buffer: the delete that we are now
1452 * processing might obsolete an old log entry, so by
1453 * committing, we can satisfy the buffer's checkpoint.
1454 *
1455 * So, if we have a checkpoint on the buffer, we should
1456 * now refile the buffer on our BJ_Forget list so that
1457 * we know to remove the checkpoint after we commit.
1458 */
1459
Theodore Ts'o0bfea812014-03-09 00:56:58 -05001460 spin_lock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001461 if (jh->b_cp_transaction) {
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001462 __jbd2_journal_temp_unlink_buffer(jh);
1463 __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001464 } else {
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001465 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001466 if (!buffer_jbd(bh)) {
1467 spin_unlock(&journal->j_list_lock);
1468 jbd_unlock_bh_state(bh);
1469 __bforget(bh);
1470 goto drop;
1471 }
1472 }
Theodore Ts'o0bfea812014-03-09 00:56:58 -05001473 spin_unlock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001474 } else if (jh->b_transaction) {
1475 J_ASSERT_JH(jh, (jh->b_transaction ==
1476 journal->j_committing_transaction));
1477 /* However, if the buffer is still owned by a prior
1478 * (committing) transaction, we can't drop it yet... */
1479 JBUFFER_TRACE(jh, "belongs to older transaction");
1480 /* ... but we CAN drop it from the new transaction if we
1481 * have also modified it since the original commit. */
1482
1483 if (jh->b_next_transaction) {
1484 J_ASSERT(jh->b_next_transaction == transaction);
Theodore Ts'o0bfea812014-03-09 00:56:58 -05001485 spin_lock(&journal->j_list_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001486 jh->b_next_transaction = NULL;
Theodore Ts'o0bfea812014-03-09 00:56:58 -05001487 spin_unlock(&journal->j_list_lock);
Josef Bacik1dfc3222008-04-17 10:38:59 -04001488
1489 /*
1490 * only drop a reference if this transaction modified
1491 * the buffer
1492 */
1493 if (was_modified)
1494 drop_reserve = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001495 }
1496 }
1497
1498not_jbd:
Dave Kleikamp470decc2006-10-11 01:20:57 -07001499 jbd_unlock_bh_state(bh);
1500 __brelse(bh);
1501drop:
1502 if (drop_reserve) {
1503 /* no need to reserve log space for this block -bzzz */
1504 handle->h_buffer_credits++;
1505 }
1506 return err;
1507}
1508
1509/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001510 * int jbd2_journal_stop() - complete a transaction
Dave Kleikamp470decc2006-10-11 01:20:57 -07001511 * @handle: tranaction to complete.
1512 *
1513 * All done for a particular handle.
1514 *
1515 * There is not much action needed here. We just return any remaining
1516 * buffer credits to the transaction and remove the handle. The only
1517 * complication is that we need to start a commit operation if the
1518 * filesystem is marked for synchronous update.
1519 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001520 * jbd2_journal_stop itself will not usually return an error, but it may
Dave Kleikamp470decc2006-10-11 01:20:57 -07001521 * do so in unusual circumstances. In particular, expect it to
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001522 * return -EIO if a jbd2_journal_abort has been executed since the
Dave Kleikamp470decc2006-10-11 01:20:57 -07001523 * transaction began.
1524 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001525int jbd2_journal_stop(handle_t *handle)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001526{
1527 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001528 journal_t *journal;
1529 int err = 0, wait_for_commit = 0;
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001530 tid_t tid;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001531 pid_t pid;
1532
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001533 if (!transaction)
1534 goto free_and_exit;
1535 journal = transaction->t_journal;
1536
Dave Kleikamp470decc2006-10-11 01:20:57 -07001537 J_ASSERT(journal_current_handle() == handle);
1538
1539 if (is_handle_aborted(handle))
1540 err = -EIO;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001541 else
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001542 J_ASSERT(atomic_read(&transaction->t_updates) > 0);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001543
1544 if (--handle->h_ref > 0) {
1545 jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
1546 handle->h_ref);
1547 return err;
1548 }
1549
1550 jbd_debug(4, "Handle %p going down\n", handle);
Theodore Ts'o343d9c22013-02-08 13:00:22 -05001551 trace_jbd2_handle_stats(journal->j_fs_dev->bd_dev,
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001552 transaction->t_tid,
Theodore Ts'o343d9c22013-02-08 13:00:22 -05001553 handle->h_type, handle->h_line_no,
1554 jiffies - handle->h_start_jiffies,
1555 handle->h_sync, handle->h_requested_credits,
1556 (handle->h_requested_credits -
1557 handle->h_buffer_credits));
Dave Kleikamp470decc2006-10-11 01:20:57 -07001558
1559 /*
1560 * Implement synchronous transaction batching. If the handle
1561 * was synchronous, don't force a commit immediately. Let's
Josef Bacike07f7182008-11-26 01:14:26 -05001562 * yield and let another thread piggyback onto this
1563 * transaction. Keep doing that while new threads continue to
1564 * arrive. It doesn't cost much - we're about to run a commit
1565 * and sleep on IO anyway. Speeds up many-threaded, many-dir
1566 * operations by 30x or more...
Dave Kleikamp470decc2006-10-11 01:20:57 -07001567 *
Josef Bacike07f7182008-11-26 01:14:26 -05001568 * We try and optimize the sleep time against what the
1569 * underlying disk can do, instead of having a static sleep
1570 * time. This is useful for the case where our storage is so
1571 * fast that it is more optimal to go ahead and force a flush
1572 * and wait for the transaction to be committed than it is to
1573 * wait for an arbitrary amount of time for new writers to
1574 * join the transaction. We achieve this by measuring how
1575 * long it takes to commit a transaction, and compare it with
1576 * how long this transaction has been running, and if run time
1577 * < commit time then we sleep for the delta and commit. This
1578 * greatly helps super fast disks that would see slowdowns as
1579 * more threads started doing fsyncs.
1580 *
1581 * But don't do this if this process was the most recent one
1582 * to perform a synchronous write. We do this to detect the
1583 * case where a single process is doing a stream of sync
1584 * writes. No point in waiting for joiners in that case.
Eric Sandeen5dd21422014-07-05 19:18:22 -04001585 *
1586 * Setting max_batch_time to 0 disables this completely.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001587 */
1588 pid = current->pid;
Eric Sandeen5dd21422014-07-05 19:18:22 -04001589 if (handle->h_sync && journal->j_last_sync_writer != pid &&
1590 journal->j_max_batch_time) {
Josef Bacike07f7182008-11-26 01:14:26 -05001591 u64 commit_time, trans_time;
1592
Dave Kleikamp470decc2006-10-11 01:20:57 -07001593 journal->j_last_sync_writer = pid;
Josef Bacike07f7182008-11-26 01:14:26 -05001594
Theodore Ts'oa931da62010-08-03 21:35:12 -04001595 read_lock(&journal->j_state_lock);
Josef Bacike07f7182008-11-26 01:14:26 -05001596 commit_time = journal->j_average_commit_time;
Theodore Ts'oa931da62010-08-03 21:35:12 -04001597 read_unlock(&journal->j_state_lock);
Josef Bacike07f7182008-11-26 01:14:26 -05001598
1599 trans_time = ktime_to_ns(ktime_sub(ktime_get(),
1600 transaction->t_start_time));
1601
Theodore Ts'o30773842009-01-03 20:27:38 -05001602 commit_time = max_t(u64, commit_time,
1603 1000*journal->j_min_batch_time);
Josef Bacike07f7182008-11-26 01:14:26 -05001604 commit_time = min_t(u64, commit_time,
Theodore Ts'o30773842009-01-03 20:27:38 -05001605 1000*journal->j_max_batch_time);
Josef Bacike07f7182008-11-26 01:14:26 -05001606
1607 if (trans_time < commit_time) {
1608 ktime_t expires = ktime_add_ns(ktime_get(),
1609 commit_time);
1610 set_current_state(TASK_UNINTERRUPTIBLE);
1611 schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
1612 }
Dave Kleikamp470decc2006-10-11 01:20:57 -07001613 }
1614
Theodore Ts'o70585482009-03-25 23:35:46 -04001615 if (handle->h_sync)
1616 transaction->t_synchronous_commit = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001617 current->journal_info = NULL;
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001618 atomic_sub(handle->h_buffer_credits,
1619 &transaction->t_outstanding_credits);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001620
1621 /*
1622 * If the handle is marked SYNC, we need to set another commit
1623 * going! We also want to force a commit if the current
1624 * transaction is occupying too much of the log, or if the
1625 * transaction is too old now.
1626 */
1627 if (handle->h_sync ||
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001628 (atomic_read(&transaction->t_outstanding_credits) >
1629 journal->j_max_transaction_buffers) ||
1630 time_after_eq(jiffies, transaction->t_expires)) {
Dave Kleikamp470decc2006-10-11 01:20:57 -07001631 /* Do this even for aborted journals: an abort still
1632 * completes the commit thread, it just doesn't write
1633 * anything to disk. */
Dave Kleikamp470decc2006-10-11 01:20:57 -07001634
Dave Kleikamp470decc2006-10-11 01:20:57 -07001635 jbd_debug(2, "transaction too old, requesting commit for "
1636 "handle %p\n", handle);
1637 /* This is non-blocking */
Theodore Ts'oc35a56a2010-05-16 05:00:00 -04001638 jbd2_log_start_commit(journal, transaction->t_tid);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001639
1640 /*
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001641 * Special case: JBD2_SYNC synchronous updates require us
Dave Kleikamp470decc2006-10-11 01:20:57 -07001642 * to wait for the commit to complete.
1643 */
1644 if (handle->h_sync && !(current->flags & PF_MEMALLOC))
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001645 wait_for_commit = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001646 }
1647
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001648 /*
1649 * Once we drop t_updates, if it goes to zero the transaction
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001650 * could start committing on us and eventually disappear. So
Theodore Ts'oa51dca92010-08-02 08:43:25 -04001651 * once we do this, we must not dereference transaction
1652 * pointer again.
1653 */
1654 tid = transaction->t_tid;
1655 if (atomic_dec_and_test(&transaction->t_updates)) {
1656 wake_up(&journal->j_wait_updates);
1657 if (journal->j_barrier_count)
1658 wake_up(&journal->j_wait_transaction_locked);
1659 }
1660
1661 if (wait_for_commit)
1662 err = jbd2_log_wait_commit(journal, tid);
1663
Ingo Molnar3295f0e2008-08-11 10:30:30 +02001664 lock_map_release(&handle->h_lockdep_map);
Mingming Cao7b751062008-01-28 23:58:27 -05001665
Jan Kara8f7d89f2013-06-04 12:35:11 -04001666 if (handle->h_rsv_handle)
1667 jbd2_journal_free_reserved(handle->h_rsv_handle);
Theodore Ts'o41a5b912013-07-01 08:12:41 -04001668free_and_exit:
Mingming Caoaf1e76d2007-10-16 18:38:25 -04001669 jbd2_free_handle(handle);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001670 return err;
1671}
1672
Dave Kleikamp470decc2006-10-11 01:20:57 -07001673/*
1674 *
1675 * List management code snippets: various functions for manipulating the
1676 * transaction buffer lists.
1677 *
1678 */
1679
1680/*
1681 * Append a buffer to a transaction list, given the transaction's list head
1682 * pointer.
1683 *
1684 * j_list_lock is held.
1685 *
1686 * jbd_lock_bh_state(jh2bh(jh)) is held.
1687 */
1688
1689static inline void
1690__blist_add_buffer(struct journal_head **list, struct journal_head *jh)
1691{
1692 if (!*list) {
1693 jh->b_tnext = jh->b_tprev = jh;
1694 *list = jh;
1695 } else {
1696 /* Insert at the tail of the list to preserve order */
1697 struct journal_head *first = *list, *last = first->b_tprev;
1698 jh->b_tprev = last;
1699 jh->b_tnext = first;
1700 last->b_tnext = first->b_tprev = jh;
1701 }
1702}
1703
1704/*
1705 * Remove a buffer from a transaction list, given the transaction's list
1706 * head pointer.
1707 *
1708 * Called with j_list_lock held, and the journal may not be locked.
1709 *
1710 * jbd_lock_bh_state(jh2bh(jh)) is held.
1711 */
1712
1713static inline void
1714__blist_del_buffer(struct journal_head **list, struct journal_head *jh)
1715{
1716 if (*list == jh) {
1717 *list = jh->b_tnext;
1718 if (*list == jh)
1719 *list = NULL;
1720 }
1721 jh->b_tprev->b_tnext = jh->b_tnext;
1722 jh->b_tnext->b_tprev = jh->b_tprev;
1723}
1724
1725/*
1726 * Remove a buffer from the appropriate transaction list.
1727 *
1728 * Note that this function can *change* the value of
Jan Karaf5113ef2013-06-04 12:01:45 -04001729 * bh->b_transaction->t_buffers, t_forget, t_shadow_list, t_log_list or
1730 * t_reserved_list. If the caller is holding onto a copy of one of these
1731 * pointers, it could go bad. Generally the caller needs to re-read the
1732 * pointer from the transaction_t.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001733 *
Jan Kara5bebccf2012-03-13 22:25:06 -04001734 * Called under j_list_lock.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001735 */
Jan Kara5bebccf2012-03-13 22:25:06 -04001736static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001737{
1738 struct journal_head **list = NULL;
1739 transaction_t *transaction;
1740 struct buffer_head *bh = jh2bh(jh);
1741
1742 J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
1743 transaction = jh->b_transaction;
1744 if (transaction)
1745 assert_spin_locked(&transaction->t_journal->j_list_lock);
1746
1747 J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
1748 if (jh->b_jlist != BJ_None)
Mingming Cao40191912008-01-28 23:58:27 -05001749 J_ASSERT_JH(jh, transaction != NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001750
1751 switch (jh->b_jlist) {
1752 case BJ_None:
1753 return;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001754 case BJ_Metadata:
1755 transaction->t_nr_buffers--;
1756 J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
1757 list = &transaction->t_buffers;
1758 break;
1759 case BJ_Forget:
1760 list = &transaction->t_forget;
1761 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001762 case BJ_Shadow:
1763 list = &transaction->t_shadow_list;
1764 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001765 case BJ_Reserved:
1766 list = &transaction->t_reserved_list;
1767 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001768 }
1769
1770 __blist_del_buffer(list, jh);
1771 jh->b_jlist = BJ_None;
1772 if (test_clear_buffer_jbddirty(bh))
1773 mark_buffer_dirty(bh); /* Expose it to the VM */
1774}
1775
Jan Karade1b7942011-06-13 15:38:22 -04001776/*
1777 * Remove buffer from all transactions.
1778 *
1779 * Called with bh_state lock and j_list_lock
1780 *
1781 * jh and bh may be already freed when this function returns.
1782 */
1783static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001784{
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001785 __jbd2_journal_temp_unlink_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001786 jh->b_transaction = NULL;
Jan Karade1b7942011-06-13 15:38:22 -04001787 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001788}
1789
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001790void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001791{
Jan Karade1b7942011-06-13 15:38:22 -04001792 struct buffer_head *bh = jh2bh(jh);
1793
1794 /* Get reference so that buffer cannot be freed before we unlock it */
1795 get_bh(bh);
1796 jbd_lock_bh_state(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001797 spin_lock(&journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001798 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001799 spin_unlock(&journal->j_list_lock);
Jan Karade1b7942011-06-13 15:38:22 -04001800 jbd_unlock_bh_state(bh);
1801 __brelse(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001802}
1803
1804/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001805 * Called from jbd2_journal_try_to_free_buffers().
Dave Kleikamp470decc2006-10-11 01:20:57 -07001806 *
1807 * Called under jbd_lock_bh_state(bh)
1808 */
1809static void
1810__journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
1811{
1812 struct journal_head *jh;
1813
1814 jh = bh2jh(bh);
1815
1816 if (buffer_locked(bh) || buffer_dirty(bh))
1817 goto out;
1818
Theodore Ts'od2eb0b92014-03-09 00:07:19 -05001819 if (jh->b_next_transaction != NULL || jh->b_transaction != NULL)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001820 goto out;
1821
1822 spin_lock(&journal->j_list_lock);
Theodore Ts'od2eb0b92014-03-09 00:07:19 -05001823 if (jh->b_cp_transaction != NULL) {
Dave Kleikamp470decc2006-10-11 01:20:57 -07001824 /* written-back checkpointed metadata buffer */
Jan Karac254c9e2012-03-13 22:27:44 -04001825 JBUFFER_TRACE(jh, "remove from checkpoint list");
1826 __jbd2_journal_remove_checkpoint(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001827 }
1828 spin_unlock(&journal->j_list_lock);
1829out:
1830 return;
1831}
1832
Dave Kleikamp470decc2006-10-11 01:20:57 -07001833/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001834 * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001835 * @journal: journal for operation
1836 * @page: to try and free
Mingming Cao530576b2008-07-13 21:06:39 -04001837 * @gfp_mask: we use the mask to detect how hard should we try to release
1838 * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to
1839 * release the buffers.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001840 *
1841 *
1842 * For all the buffers on this page,
1843 * if they are fully written out ordered data, move them onto BUF_CLEAN
1844 * so try_to_free_buffers() can reap them.
1845 *
1846 * This function returns non-zero if we wish try_to_free_buffers()
1847 * to be called. We do this if the page is releasable by try_to_free_buffers().
1848 * We also do it if the page has locked or dirty buffers and the caller wants
1849 * us to perform sync or async writeout.
1850 *
1851 * This complicates JBD locking somewhat. We aren't protected by the
1852 * BKL here. We wish to remove the buffer from its committing or
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001853 * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer.
Dave Kleikamp470decc2006-10-11 01:20:57 -07001854 *
1855 * This may *change* the value of transaction_t->t_datalist, so anyone
1856 * who looks at t_datalist needs to lock against this function.
1857 *
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001858 * Even worse, someone may be doing a jbd2_journal_dirty_data on this
1859 * buffer. So we need to lock against that. jbd2_journal_dirty_data()
Dave Kleikamp470decc2006-10-11 01:20:57 -07001860 * will come out of the lock with the buffer dirty, which makes it
1861 * ineligible for release here.
1862 *
1863 * Who else is affected by this? hmm... Really the only contender
1864 * is do_get_write_access() - it could be looking at the buffer while
1865 * journal_try_to_free_buffer() is changing its state. But that
1866 * cannot happen because we never reallocate freed data as metadata
1867 * while the data is part of a transaction. Yes?
Mingming Cao530576b2008-07-13 21:06:39 -04001868 *
1869 * Return 0 on failure, 1 on success
Dave Kleikamp470decc2006-10-11 01:20:57 -07001870 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001871int jbd2_journal_try_to_free_buffers(journal_t *journal,
Mingming Cao530576b2008-07-13 21:06:39 -04001872 struct page *page, gfp_t gfp_mask)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001873{
1874 struct buffer_head *head;
1875 struct buffer_head *bh;
1876 int ret = 0;
1877
1878 J_ASSERT(PageLocked(page));
1879
1880 head = page_buffers(page);
1881 bh = head;
1882 do {
1883 struct journal_head *jh;
1884
1885 /*
1886 * We take our own ref against the journal_head here to avoid
1887 * having to add tons of locking around each instance of
Mingming Cao530576b2008-07-13 21:06:39 -04001888 * jbd2_journal_put_journal_head().
Dave Kleikamp470decc2006-10-11 01:20:57 -07001889 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001890 jh = jbd2_journal_grab_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001891 if (!jh)
1892 continue;
1893
1894 jbd_lock_bh_state(bh);
1895 __journal_try_to_free_buffer(journal, bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001896 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001897 jbd_unlock_bh_state(bh);
1898 if (buffer_jbd(bh))
1899 goto busy;
1900 } while ((bh = bh->b_this_page) != head);
Mingming Cao530576b2008-07-13 21:06:39 -04001901
Dave Kleikamp470decc2006-10-11 01:20:57 -07001902 ret = try_to_free_buffers(page);
Mingming Cao530576b2008-07-13 21:06:39 -04001903
Dave Kleikamp470decc2006-10-11 01:20:57 -07001904busy:
1905 return ret;
1906}
1907
1908/*
1909 * This buffer is no longer needed. If it is on an older transaction's
1910 * checkpoint list we need to record it on this transaction's forget list
1911 * to pin this buffer (and hence its checkpointing transaction) down until
1912 * this transaction commits. If the buffer isn't on a checkpoint list, we
1913 * release it.
1914 * Returns non-zero if JBD no longer has an interest in the buffer.
1915 *
1916 * Called under j_list_lock.
1917 *
1918 * Called under jbd_lock_bh_state(bh).
1919 */
1920static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
1921{
1922 int may_free = 1;
1923 struct buffer_head *bh = jh2bh(jh);
1924
Dave Kleikamp470decc2006-10-11 01:20:57 -07001925 if (jh->b_cp_transaction) {
1926 JBUFFER_TRACE(jh, "on running+cp transaction");
Jan Karade1b7942011-06-13 15:38:22 -04001927 __jbd2_journal_temp_unlink_buffer(jh);
Jan Karaf91d1d02009-07-13 16:16:20 -04001928 /*
1929 * We don't want to write the buffer anymore, clear the
1930 * bit so that we don't confuse checks in
1931 * __journal_file_buffer
1932 */
1933 clear_buffer_dirty(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001934 __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001935 may_free = 0;
1936 } else {
1937 JBUFFER_TRACE(jh, "on running transaction");
Jan Karade1b7942011-06-13 15:38:22 -04001938 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07001939 }
1940 return may_free;
1941}
1942
1943/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -07001944 * jbd2_journal_invalidatepage
Dave Kleikamp470decc2006-10-11 01:20:57 -07001945 *
1946 * This code is tricky. It has a number of cases to deal with.
1947 *
1948 * There are two invariants which this code relies on:
1949 *
1950 * i_size must be updated on disk before we start calling invalidatepage on the
1951 * data.
1952 *
1953 * This is done in ext3 by defining an ext3_setattr method which
1954 * updates i_size before truncate gets going. By maintaining this
1955 * invariant, we can be sure that it is safe to throw away any buffers
1956 * attached to the current transaction: once the transaction commits,
1957 * we know that the data will not be needed.
1958 *
1959 * Note however that we can *not* throw away data belonging to the
1960 * previous, committing transaction!
1961 *
1962 * Any disk blocks which *are* part of the previous, committing
1963 * transaction (and which therefore cannot be discarded immediately) are
1964 * not going to be reused in the new running transaction
1965 *
1966 * The bitmap committed_data images guarantee this: any block which is
1967 * allocated in one transaction and removed in the next will be marked
1968 * as in-use in the committed_data bitmap, so cannot be reused until
1969 * the next transaction to delete the block commits. This means that
1970 * leaving committing buffers dirty is quite safe: the disk blocks
1971 * cannot be reallocated to a different file and so buffer aliasing is
1972 * not possible.
1973 *
1974 *
1975 * The above applies mainly to ordered data mode. In writeback mode we
1976 * don't make guarantees about the order in which data hits disk --- in
1977 * particular we don't guarantee that new dirty data is flushed before
1978 * transaction commit --- so it is always safe just to discard data
1979 * immediately in that mode. --sct
1980 */
1981
1982/*
1983 * The journal_unmap_buffer helper function returns zero if the buffer
1984 * concerned remains pinned as an anonymous buffer belonging to an older
1985 * transaction.
1986 *
1987 * We're outside-transaction here. Either or both of j_running_transaction
1988 * and j_committing_transaction may be NULL.
1989 */
Jan Karab794e7a2012-09-26 23:11:13 -04001990static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
1991 int partial_page)
Dave Kleikamp470decc2006-10-11 01:20:57 -07001992{
1993 transaction_t *transaction;
1994 struct journal_head *jh;
1995 int may_free = 1;
Dave Kleikamp470decc2006-10-11 01:20:57 -07001996
1997 BUFFER_TRACE(bh, "entry");
1998
1999 /*
2000 * It is safe to proceed here without the j_list_lock because the
2001 * buffers cannot be stolen by try_to_free_buffers as long as we are
2002 * holding the page lock. --sct
2003 */
2004
2005 if (!buffer_jbd(bh))
2006 goto zap_buffer_unlocked;
2007
Jan Kara87c89c22008-07-11 19:27:31 -04002008 /* OK, we have data buffer in journaled mode */
Theodore Ts'oa931da62010-08-03 21:35:12 -04002009 write_lock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002010 jbd_lock_bh_state(bh);
2011 spin_lock(&journal->j_list_lock);
2012
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002013 jh = jbd2_journal_grab_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002014 if (!jh)
2015 goto zap_buffer_no_jh;
2016
dingdinghuaba869022010-02-15 16:35:42 -05002017 /*
2018 * We cannot remove the buffer from checkpoint lists until the
2019 * transaction adding inode to orphan list (let's call it T)
2020 * is committed. Otherwise if the transaction changing the
2021 * buffer would be cleaned from the journal before T is
2022 * committed, a crash will cause that the correct contents of
2023 * the buffer will be lost. On the other hand we have to
2024 * clear the buffer dirty bit at latest at the moment when the
2025 * transaction marking the buffer as freed in the filesystem
2026 * structures is committed because from that moment on the
Jan Karab794e7a2012-09-26 23:11:13 -04002027 * block can be reallocated and used by a different page.
dingdinghuaba869022010-02-15 16:35:42 -05002028 * Since the block hasn't been freed yet but the inode has
2029 * already been added to orphan list, it is safe for us to add
2030 * the buffer to BJ_Forget list of the newest transaction.
Jan Karab794e7a2012-09-26 23:11:13 -04002031 *
2032 * Also we have to clear buffer_mapped flag of a truncated buffer
2033 * because the buffer_head may be attached to the page straddling
2034 * i_size (can happen only when blocksize < pagesize) and thus the
2035 * buffer_head can be reused when the file is extended again. So we end
2036 * up keeping around invalidated buffers attached to transactions'
2037 * BJ_Forget list just to stop checkpointing code from cleaning up
2038 * the transaction this buffer was modified in.
dingdinghuaba869022010-02-15 16:35:42 -05002039 */
Dave Kleikamp470decc2006-10-11 01:20:57 -07002040 transaction = jh->b_transaction;
2041 if (transaction == NULL) {
2042 /* First case: not on any transaction. If it
2043 * has no checkpoint link, then we can zap it:
2044 * it's a writeback-mode buffer so we don't care
2045 * if it hits disk safely. */
2046 if (!jh->b_cp_transaction) {
2047 JBUFFER_TRACE(jh, "not on any transaction: zap");
2048 goto zap_buffer;
2049 }
2050
2051 if (!buffer_dirty(bh)) {
2052 /* bdflush has written it. We can drop it now */
2053 goto zap_buffer;
2054 }
2055
2056 /* OK, it must be in the journal but still not
2057 * written fully to disk: it's metadata or
2058 * journaled data... */
2059
2060 if (journal->j_running_transaction) {
2061 /* ... and once the current transaction has
2062 * committed, the buffer won't be needed any
2063 * longer. */
2064 JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget");
Jan Karab794e7a2012-09-26 23:11:13 -04002065 may_free = __dispose_buffer(jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -07002066 journal->j_running_transaction);
Jan Karab794e7a2012-09-26 23:11:13 -04002067 goto zap_buffer;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002068 } else {
2069 /* There is no currently-running transaction. So the
2070 * orphan record which we wrote for this file must have
2071 * passed into commit. We must attach this buffer to
2072 * the committing transaction, if it exists. */
2073 if (journal->j_committing_transaction) {
2074 JBUFFER_TRACE(jh, "give to committing trans");
Jan Karab794e7a2012-09-26 23:11:13 -04002075 may_free = __dispose_buffer(jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -07002076 journal->j_committing_transaction);
Jan Karab794e7a2012-09-26 23:11:13 -04002077 goto zap_buffer;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002078 } else {
2079 /* The orphan record's transaction has
2080 * committed. We can cleanse this buffer */
2081 clear_buffer_jbddirty(bh);
2082 goto zap_buffer;
2083 }
2084 }
2085 } else if (transaction == journal->j_committing_transaction) {
Eric Sandeen9b579882006-10-28 10:38:28 -07002086 JBUFFER_TRACE(jh, "on committing transaction");
Dave Kleikamp470decc2006-10-11 01:20:57 -07002087 /*
dingdinghuaba869022010-02-15 16:35:42 -05002088 * The buffer is committing, we simply cannot touch
Jan Karab794e7a2012-09-26 23:11:13 -04002089 * it. If the page is straddling i_size we have to wait
2090 * for commit and try again.
2091 */
2092 if (partial_page) {
Jan Karab794e7a2012-09-26 23:11:13 -04002093 jbd2_journal_put_journal_head(jh);
2094 spin_unlock(&journal->j_list_lock);
2095 jbd_unlock_bh_state(bh);
2096 write_unlock(&journal->j_state_lock);
Jan Kara53e87262012-12-25 13:29:52 -05002097 return -EBUSY;
Jan Karab794e7a2012-09-26 23:11:13 -04002098 }
2099 /*
2100 * OK, buffer won't be reachable after truncate. We just set
2101 * j_next_transaction to the running transaction (if there is
2102 * one) and mark buffer as freed so that commit code knows it
2103 * should clear dirty bits when it is done with the buffer.
dingdinghuaba869022010-02-15 16:35:42 -05002104 */
Dave Kleikamp470decc2006-10-11 01:20:57 -07002105 set_buffer_freed(bh);
dingdinghuaba869022010-02-15 16:35:42 -05002106 if (journal->j_running_transaction && buffer_jbddirty(bh))
2107 jh->b_next_transaction = journal->j_running_transaction;
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002108 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002109 spin_unlock(&journal->j_list_lock);
2110 jbd_unlock_bh_state(bh);
Theodore Ts'oa931da62010-08-03 21:35:12 -04002111 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002112 return 0;
2113 } else {
2114 /* Good, the buffer belongs to the running transaction.
2115 * We are writing our own transaction's data, not any
2116 * previous one's, so it is safe to throw it away
2117 * (remember that we expect the filesystem to have set
2118 * i_size already for this truncate so recovery will not
2119 * expose the disk blocks we are discarding here.) */
2120 J_ASSERT_JH(jh, transaction == journal->j_running_transaction);
Eric Sandeen9b579882006-10-28 10:38:28 -07002121 JBUFFER_TRACE(jh, "on running transaction");
Dave Kleikamp470decc2006-10-11 01:20:57 -07002122 may_free = __dispose_buffer(jh, transaction);
2123 }
2124
2125zap_buffer:
Jan Karab794e7a2012-09-26 23:11:13 -04002126 /*
2127 * This is tricky. Although the buffer is truncated, it may be reused
2128 * if blocksize < pagesize and it is attached to the page straddling
2129 * EOF. Since the buffer might have been added to BJ_Forget list of the
2130 * running transaction, journal_get_write_access() won't clear
2131 * b_modified and credit accounting gets confused. So clear b_modified
2132 * here.
2133 */
2134 jh->b_modified = 0;
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002135 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002136zap_buffer_no_jh:
2137 spin_unlock(&journal->j_list_lock);
2138 jbd_unlock_bh_state(bh);
Theodore Ts'oa931da62010-08-03 21:35:12 -04002139 write_unlock(&journal->j_state_lock);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002140zap_buffer_unlocked:
2141 clear_buffer_dirty(bh);
2142 J_ASSERT_BH(bh, !buffer_jbddirty(bh));
2143 clear_buffer_mapped(bh);
2144 clear_buffer_req(bh);
2145 clear_buffer_new(bh);
Eric Sandeen15291162012-02-20 17:53:01 -05002146 clear_buffer_delay(bh);
2147 clear_buffer_unwritten(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002148 bh->b_bdev = NULL;
2149 return may_free;
2150}
2151
2152/**
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002153 * void jbd2_journal_invalidatepage()
Dave Kleikamp470decc2006-10-11 01:20:57 -07002154 * @journal: journal to use for flush...
2155 * @page: page to flush
Lukas Czerner259709b2013-05-21 23:20:03 -04002156 * @offset: start of the range to invalidate
2157 * @length: length of the range to invalidate
Dave Kleikamp470decc2006-10-11 01:20:57 -07002158 *
Lukas Czerner259709b2013-05-21 23:20:03 -04002159 * Reap page buffers containing data after in the specified range in page.
2160 * Can return -EBUSY if buffers are part of the committing transaction and
2161 * the page is straddling i_size. Caller then has to wait for current commit
2162 * and try again.
Dave Kleikamp470decc2006-10-11 01:20:57 -07002163 */
Jan Kara53e87262012-12-25 13:29:52 -05002164int jbd2_journal_invalidatepage(journal_t *journal,
2165 struct page *page,
Lukas Czerner259709b2013-05-21 23:20:03 -04002166 unsigned int offset,
2167 unsigned int length)
Dave Kleikamp470decc2006-10-11 01:20:57 -07002168{
2169 struct buffer_head *head, *bh, *next;
Lukas Czerner259709b2013-05-21 23:20:03 -04002170 unsigned int stop = offset + length;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002171 unsigned int curr_off = 0;
Lukas Czerner259709b2013-05-21 23:20:03 -04002172 int partial_page = (offset || length < PAGE_CACHE_SIZE);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002173 int may_free = 1;
Jan Kara53e87262012-12-25 13:29:52 -05002174 int ret = 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002175
2176 if (!PageLocked(page))
2177 BUG();
2178 if (!page_has_buffers(page))
Jan Kara53e87262012-12-25 13:29:52 -05002179 return 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002180
Lukas Czerner259709b2013-05-21 23:20:03 -04002181 BUG_ON(stop > PAGE_CACHE_SIZE || stop < length);
2182
Dave Kleikamp470decc2006-10-11 01:20:57 -07002183 /* We will potentially be playing with lists other than just the
2184 * data lists (especially for journaled data mode), so be
2185 * cautious in our locking. */
2186
2187 head = bh = page_buffers(page);
2188 do {
2189 unsigned int next_off = curr_off + bh->b_size;
2190 next = bh->b_this_page;
2191
Lukas Czerner259709b2013-05-21 23:20:03 -04002192 if (next_off > stop)
2193 return 0;
2194
Dave Kleikamp470decc2006-10-11 01:20:57 -07002195 if (offset <= curr_off) {
2196 /* This block is wholly outside the truncation point */
2197 lock_buffer(bh);
Lukas Czerner259709b2013-05-21 23:20:03 -04002198 ret = journal_unmap_buffer(journal, bh, partial_page);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002199 unlock_buffer(bh);
Jan Kara53e87262012-12-25 13:29:52 -05002200 if (ret < 0)
2201 return ret;
2202 may_free &= ret;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002203 }
2204 curr_off = next_off;
2205 bh = next;
2206
2207 } while (bh != head);
2208
Lukas Czerner259709b2013-05-21 23:20:03 -04002209 if (!partial_page) {
Dave Kleikamp470decc2006-10-11 01:20:57 -07002210 if (may_free && try_to_free_buffers(page))
2211 J_ASSERT(!page_has_buffers(page));
2212 }
Jan Kara53e87262012-12-25 13:29:52 -05002213 return 0;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002214}
2215
2216/*
2217 * File a buffer on the given transaction list.
2218 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002219void __jbd2_journal_file_buffer(struct journal_head *jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -07002220 transaction_t *transaction, int jlist)
2221{
2222 struct journal_head **list = NULL;
2223 int was_dirty = 0;
2224 struct buffer_head *bh = jh2bh(jh);
2225
2226 J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2227 assert_spin_locked(&transaction->t_journal->j_list_lock);
2228
2229 J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
2230 J_ASSERT_JH(jh, jh->b_transaction == transaction ||
Mingming Cao40191912008-01-28 23:58:27 -05002231 jh->b_transaction == NULL);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002232
2233 if (jh->b_transaction && jh->b_jlist == jlist)
2234 return;
2235
Dave Kleikamp470decc2006-10-11 01:20:57 -07002236 if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
2237 jlist == BJ_Shadow || jlist == BJ_Forget) {
Jan Karaf91d1d02009-07-13 16:16:20 -04002238 /*
2239 * For metadata buffers, we track dirty bit in buffer_jbddirty
2240 * instead of buffer_dirty. We should not see a dirty bit set
2241 * here because we clear it in do_get_write_access but e.g.
2242 * tune2fs can modify the sb and set the dirty bit at any time
2243 * so we try to gracefully handle that.
2244 */
2245 if (buffer_dirty(bh))
2246 warn_dirty_buffer(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002247 if (test_clear_buffer_dirty(bh) ||
2248 test_clear_buffer_jbddirty(bh))
2249 was_dirty = 1;
2250 }
2251
2252 if (jh->b_transaction)
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002253 __jbd2_journal_temp_unlink_buffer(jh);
Jan Karade1b7942011-06-13 15:38:22 -04002254 else
2255 jbd2_journal_grab_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002256 jh->b_transaction = transaction;
2257
2258 switch (jlist) {
2259 case BJ_None:
2260 J_ASSERT_JH(jh, !jh->b_committed_data);
2261 J_ASSERT_JH(jh, !jh->b_frozen_data);
2262 return;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002263 case BJ_Metadata:
2264 transaction->t_nr_buffers++;
2265 list = &transaction->t_buffers;
2266 break;
2267 case BJ_Forget:
2268 list = &transaction->t_forget;
2269 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002270 case BJ_Shadow:
2271 list = &transaction->t_shadow_list;
2272 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002273 case BJ_Reserved:
2274 list = &transaction->t_reserved_list;
2275 break;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002276 }
2277
2278 __blist_add_buffer(list, jh);
2279 jh->b_jlist = jlist;
2280
2281 if (was_dirty)
2282 set_buffer_jbddirty(bh);
2283}
2284
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002285void jbd2_journal_file_buffer(struct journal_head *jh,
Dave Kleikamp470decc2006-10-11 01:20:57 -07002286 transaction_t *transaction, int jlist)
2287{
2288 jbd_lock_bh_state(jh2bh(jh));
2289 spin_lock(&transaction->t_journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002290 __jbd2_journal_file_buffer(jh, transaction, jlist);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002291 spin_unlock(&transaction->t_journal->j_list_lock);
2292 jbd_unlock_bh_state(jh2bh(jh));
2293}
2294
2295/*
2296 * Remove a buffer from its current buffer list in preparation for
2297 * dropping it from its current transaction entirely. If the buffer has
2298 * already started to be used by a subsequent transaction, refile the
2299 * buffer on that transaction's metadata list.
2300 *
Jan Karade1b7942011-06-13 15:38:22 -04002301 * Called under j_list_lock
Dave Kleikamp470decc2006-10-11 01:20:57 -07002302 * Called under jbd_lock_bh_state(jh2bh(jh))
Jan Karade1b7942011-06-13 15:38:22 -04002303 *
2304 * jh and bh may be already free when this function returns
Dave Kleikamp470decc2006-10-11 01:20:57 -07002305 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002306void __jbd2_journal_refile_buffer(struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07002307{
dingdinghuaba869022010-02-15 16:35:42 -05002308 int was_dirty, jlist;
Dave Kleikamp470decc2006-10-11 01:20:57 -07002309 struct buffer_head *bh = jh2bh(jh);
2310
2311 J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2312 if (jh->b_transaction)
2313 assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
2314
2315 /* If the buffer is now unused, just drop it. */
2316 if (jh->b_next_transaction == NULL) {
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002317 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002318 return;
2319 }
2320
2321 /*
2322 * It has been modified by a later transaction: add it to the new
2323 * transaction's metadata list.
2324 */
2325
2326 was_dirty = test_clear_buffer_jbddirty(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002327 __jbd2_journal_temp_unlink_buffer(jh);
Jan Karade1b7942011-06-13 15:38:22 -04002328 /*
2329 * We set b_transaction here because b_next_transaction will inherit
2330 * our jh reference and thus __jbd2_journal_file_buffer() must not
2331 * take a new one.
2332 */
Dave Kleikamp470decc2006-10-11 01:20:57 -07002333 jh->b_transaction = jh->b_next_transaction;
2334 jh->b_next_transaction = NULL;
dingdinghuaba869022010-02-15 16:35:42 -05002335 if (buffer_freed(bh))
2336 jlist = BJ_Forget;
2337 else if (jh->b_modified)
2338 jlist = BJ_Metadata;
2339 else
2340 jlist = BJ_Reserved;
2341 __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002342 J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
2343
2344 if (was_dirty)
2345 set_buffer_jbddirty(bh);
2346}
2347
2348/*
Jan Karade1b7942011-06-13 15:38:22 -04002349 * __jbd2_journal_refile_buffer() with necessary locking added. We take our
2350 * bh reference so that we can safely unlock bh.
Dave Kleikamp470decc2006-10-11 01:20:57 -07002351 *
Jan Karade1b7942011-06-13 15:38:22 -04002352 * The jh and bh may be freed by this call.
Dave Kleikamp470decc2006-10-11 01:20:57 -07002353 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002354void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
Dave Kleikamp470decc2006-10-11 01:20:57 -07002355{
2356 struct buffer_head *bh = jh2bh(jh);
2357
Jan Karade1b7942011-06-13 15:38:22 -04002358 /* Get reference so that buffer cannot be freed before we unlock it */
2359 get_bh(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002360 jbd_lock_bh_state(bh);
2361 spin_lock(&journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002362 __jbd2_journal_refile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002363 jbd_unlock_bh_state(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -07002364 spin_unlock(&journal->j_list_lock);
2365 __brelse(bh);
2366}
Jan Karac851ed52008-07-11 19:27:31 -04002367
2368/*
2369 * File inode in the inode list of the handle's transaction
2370 */
2371int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
2372{
2373 transaction_t *transaction = handle->h_transaction;
Theodore Ts'o41a5b912013-07-01 08:12:41 -04002374 journal_t *journal;
Jan Karac851ed52008-07-11 19:27:31 -04002375
Theodore Ts'o41a5b912013-07-01 08:12:41 -04002376 WARN_ON(!transaction);
Jan Karac851ed52008-07-11 19:27:31 -04002377 if (is_handle_aborted(handle))
Theodore Ts'o41a5b912013-07-01 08:12:41 -04002378 return -EROFS;
2379 journal = transaction->t_journal;
Jan Karac851ed52008-07-11 19:27:31 -04002380
2381 jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
2382 transaction->t_tid);
2383
2384 /*
2385 * First check whether inode isn't already on the transaction's
2386 * lists without taking the lock. Note that this check is safe
2387 * without the lock as we cannot race with somebody removing inode
2388 * from the transaction. The reason is that we remove inode from the
2389 * transaction only in journal_release_jbd_inode() and when we commit
2390 * the transaction. We are guarded from the first case by holding
2391 * a reference to the inode. We are safe against the second case
2392 * because if jinode->i_transaction == transaction, commit code
2393 * cannot touch the transaction because we hold reference to it,
2394 * and if jinode->i_next_transaction == transaction, commit code
2395 * will only file the inode where we want it.
2396 */
2397 if (jinode->i_transaction == transaction ||
2398 jinode->i_next_transaction == transaction)
2399 return 0;
2400
2401 spin_lock(&journal->j_list_lock);
2402
2403 if (jinode->i_transaction == transaction ||
2404 jinode->i_next_transaction == transaction)
2405 goto done;
2406
Jan Kara81be12c2011-05-24 11:52:40 -04002407 /*
2408 * We only ever set this variable to 1 so the test is safe. Since
2409 * t_need_data_flush is likely to be set, we do the test to save some
2410 * cacheline bouncing
2411 */
2412 if (!transaction->t_need_data_flush)
2413 transaction->t_need_data_flush = 1;
Jan Karac851ed52008-07-11 19:27:31 -04002414 /* On some different transaction's list - should be
2415 * the committing one */
2416 if (jinode->i_transaction) {
2417 J_ASSERT(jinode->i_next_transaction == NULL);
2418 J_ASSERT(jinode->i_transaction ==
2419 journal->j_committing_transaction);
2420 jinode->i_next_transaction = transaction;
2421 goto done;
2422 }
2423 /* Not on any transaction list... */
2424 J_ASSERT(!jinode->i_next_transaction);
2425 jinode->i_transaction = transaction;
2426 list_add(&jinode->i_list, &transaction->t_inode_list);
2427done:
2428 spin_unlock(&journal->j_list_lock);
2429
2430 return 0;
2431}
2432
2433/*
Jan Kara7f5aa212009-02-10 11:15:34 -05002434 * File truncate and transaction commit interact with each other in a
2435 * non-trivial way. If a transaction writing data block A is
2436 * committing, we cannot discard the data by truncate until we have
2437 * written them. Otherwise if we crashed after the transaction with
2438 * write has committed but before the transaction with truncate has
2439 * committed, we could see stale data in block A. This function is a
2440 * helper to solve this problem. It starts writeout of the truncated
2441 * part in case it is in the committing transaction.
2442 *
2443 * Filesystem code must call this function when inode is journaled in
2444 * ordered mode before truncation happens and after the inode has been
2445 * placed on orphan list with the new inode size. The second condition
2446 * avoids the race that someone writes new data and we start
2447 * committing the transaction after this function has been called but
2448 * before a transaction for truncate is started (and furthermore it
2449 * allows us to optimize the case where the addition to orphan list
2450 * happens in the same transaction as write --- we don't have to write
2451 * any data in such case).
Jan Karac851ed52008-07-11 19:27:31 -04002452 */
Jan Kara7f5aa212009-02-10 11:15:34 -05002453int jbd2_journal_begin_ordered_truncate(journal_t *journal,
2454 struct jbd2_inode *jinode,
Jan Karac851ed52008-07-11 19:27:31 -04002455 loff_t new_size)
2456{
Jan Kara7f5aa212009-02-10 11:15:34 -05002457 transaction_t *inode_trans, *commit_trans;
Jan Karac851ed52008-07-11 19:27:31 -04002458 int ret = 0;
2459
Jan Kara7f5aa212009-02-10 11:15:34 -05002460 /* This is a quick check to avoid locking if not necessary */
2461 if (!jinode->i_transaction)
Jan Karac851ed52008-07-11 19:27:31 -04002462 goto out;
Jan Kara7f5aa212009-02-10 11:15:34 -05002463 /* Locks are here just to force reading of recent values, it is
2464 * enough that the transaction was not committing before we started
2465 * a transaction adding the inode to orphan list */
Theodore Ts'oa931da62010-08-03 21:35:12 -04002466 read_lock(&journal->j_state_lock);
Jan Karac851ed52008-07-11 19:27:31 -04002467 commit_trans = journal->j_committing_transaction;
Theodore Ts'oa931da62010-08-03 21:35:12 -04002468 read_unlock(&journal->j_state_lock);
Jan Kara7f5aa212009-02-10 11:15:34 -05002469 spin_lock(&journal->j_list_lock);
2470 inode_trans = jinode->i_transaction;
2471 spin_unlock(&journal->j_list_lock);
2472 if (inode_trans == commit_trans) {
2473 ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping,
Jan Karac851ed52008-07-11 19:27:31 -04002474 new_size, LLONG_MAX);
2475 if (ret)
2476 jbd2_journal_abort(journal, ret);
2477 }
2478out:
2479 return ret;
2480}