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Diffstat (limited to 'fs/reiserfs/journal.c')
-rw-r--r--fs/reiserfs/journal.c134
1 files changed, 105 insertions, 29 deletions
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 90622200b39c..438c71f0bc91 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -429,21 +429,6 @@ static void clear_prepared_bits(struct buffer_head *bh)
clear_buffer_journal_restore_dirty(bh);
}
-/* utility function to force a BUG if it is called without the big
-** kernel lock held. caller is the string printed just before calling BUG()
-*/
-void reiserfs_check_lock_depth(struct super_block *sb, char *caller)
-{
-#ifdef CONFIG_SMP
- if (current->lock_depth < 0) {
- reiserfs_panic(sb, "journal-1", "%s called without kernel "
- "lock held", caller);
- }
-#else
- ;
-#endif
-}
-
/* return a cnode with same dev, block number and size in table, or null if not found */
static inline struct reiserfs_journal_cnode *get_journal_hash_dev(struct
super_block
@@ -552,11 +537,48 @@ static inline void insert_journal_hash(struct reiserfs_journal_cnode **table,
journal_hash(table, cn->sb, cn->blocknr) = cn;
}
+/*
+ * Several mutexes depend on the write lock.
+ * However sometimes we want to relax the write lock while we hold
+ * these mutexes, according to the release/reacquire on schedule()
+ * properties of the Bkl that were used.
+ * Reiserfs performances and locking were based on this scheme.
+ * Now that the write lock is a mutex and not the bkl anymore, doing so
+ * may result in a deadlock:
+ *
+ * A acquire write_lock
+ * A acquire j_commit_mutex
+ * A release write_lock and wait for something
+ * B acquire write_lock
+ * B can't acquire j_commit_mutex and sleep
+ * A can't acquire write lock anymore
+ * deadlock
+ *
+ * What we do here is avoiding such deadlock by playing the same game
+ * than the Bkl: if we can't acquire a mutex that depends on the write lock,
+ * we release the write lock, wait a bit and then retry.
+ *
+ * The mutexes concerned by this hack are:
+ * - The commit mutex of a journal list
+ * - The flush mutex
+ * - The journal lock
+ */
+static inline void reiserfs_mutex_lock_safe(struct mutex *m,
+ struct super_block *s)
+{
+ while (!mutex_trylock(m)) {
+ reiserfs_write_unlock(s);
+ schedule();
+ reiserfs_write_lock(s);
+ }
+}
+
/* lock the current transaction */
static inline void lock_journal(struct super_block *sb)
{
PROC_INFO_INC(sb, journal.lock_journal);
- mutex_lock(&SB_JOURNAL(sb)->j_mutex);
+
+ reiserfs_mutex_lock_safe(&SB_JOURNAL(sb)->j_mutex, sb);
}
/* unlock the current transaction */
@@ -708,7 +730,9 @@ static void check_barrier_completion(struct super_block *s,
disable_barrier(s);
set_buffer_uptodate(bh);
set_buffer_dirty(bh);
+ reiserfs_write_unlock(s);
sync_dirty_buffer(bh);
+ reiserfs_write_lock(s);
}
}
@@ -996,8 +1020,13 @@ static int reiserfs_async_progress_wait(struct super_block *s)
{
DEFINE_WAIT(wait);
struct reiserfs_journal *j = SB_JOURNAL(s);
- if (atomic_read(&j->j_async_throttle))
+
+ if (atomic_read(&j->j_async_throttle)) {
+ reiserfs_write_unlock(s);
congestion_wait(BLK_RW_ASYNC, HZ / 10);
+ reiserfs_write_lock(s);
+ }
+
return 0;
}
@@ -1043,7 +1072,8 @@ static int flush_commit_list(struct super_block *s,
}
/* make sure nobody is trying to flush this one at the same time */
- mutex_lock(&jl->j_commit_mutex);
+ reiserfs_mutex_lock_safe(&jl->j_commit_mutex, s);
+
if (!journal_list_still_alive(s, trans_id)) {
mutex_unlock(&jl->j_commit_mutex);
goto put_jl;
@@ -1061,12 +1091,17 @@ static int flush_commit_list(struct super_block *s,
if (!list_empty(&jl->j_bh_list)) {
int ret;
- unlock_kernel();
+
+ /*
+ * We might sleep in numerous places inside
+ * write_ordered_buffers. Relax the write lock.
+ */
+ reiserfs_write_unlock(s);
ret = write_ordered_buffers(&journal->j_dirty_buffers_lock,
journal, jl, &jl->j_bh_list);
if (ret < 0 && retval == 0)
retval = ret;
- lock_kernel();
+ reiserfs_write_lock(s);
}
BUG_ON(!list_empty(&jl->j_bh_list));
/*
@@ -1114,12 +1149,19 @@ static int flush_commit_list(struct super_block *s,
bn = SB_ONDISK_JOURNAL_1st_BLOCK(s) +
(jl->j_start + i) % SB_ONDISK_JOURNAL_SIZE(s);
tbh = journal_find_get_block(s, bn);
+
+ reiserfs_write_unlock(s);
wait_on_buffer(tbh);
+ reiserfs_write_lock(s);
// since we're using ll_rw_blk above, it might have skipped over
// a locked buffer. Double check here
//
- if (buffer_dirty(tbh)) /* redundant, sync_dirty_buffer() checks */
+ /* redundant, sync_dirty_buffer() checks */
+ if (buffer_dirty(tbh)) {
+ reiserfs_write_unlock(s);
sync_dirty_buffer(tbh);
+ reiserfs_write_lock(s);
+ }
if (unlikely(!buffer_uptodate(tbh))) {
#ifdef CONFIG_REISERFS_CHECK
reiserfs_warning(s, "journal-601",
@@ -1143,10 +1185,15 @@ static int flush_commit_list(struct super_block *s,
if (buffer_dirty(jl->j_commit_bh))
BUG();
mark_buffer_dirty(jl->j_commit_bh) ;
+ reiserfs_write_unlock(s);
sync_dirty_buffer(jl->j_commit_bh) ;
+ reiserfs_write_lock(s);
}
- } else
+ } else {
+ reiserfs_write_unlock(s);
wait_on_buffer(jl->j_commit_bh);
+ reiserfs_write_lock(s);
+ }
check_barrier_completion(s, jl->j_commit_bh);
@@ -1286,7 +1333,9 @@ static int _update_journal_header_block(struct super_block *sb,
if (trans_id >= journal->j_last_flush_trans_id) {
if (buffer_locked((journal->j_header_bh))) {
+ reiserfs_write_unlock(sb);
wait_on_buffer((journal->j_header_bh));
+ reiserfs_write_lock(sb);
if (unlikely(!buffer_uptodate(journal->j_header_bh))) {
#ifdef CONFIG_REISERFS_CHECK
reiserfs_warning(sb, "journal-699",
@@ -1312,12 +1361,16 @@ static int _update_journal_header_block(struct super_block *sb,
disable_barrier(sb);
goto sync;
}
+ reiserfs_write_unlock(sb);
wait_on_buffer(journal->j_header_bh);
+ reiserfs_write_lock(sb);
check_barrier_completion(sb, journal->j_header_bh);
} else {
sync:
set_buffer_dirty(journal->j_header_bh);
+ reiserfs_write_unlock(sb);
sync_dirty_buffer(journal->j_header_bh);
+ reiserfs_write_lock(sb);
}
if (!buffer_uptodate(journal->j_header_bh)) {
reiserfs_warning(sb, "journal-837",
@@ -1409,7 +1462,7 @@ static int flush_journal_list(struct super_block *s,
/* if flushall == 0, the lock is already held */
if (flushall) {
- mutex_lock(&journal->j_flush_mutex);
+ reiserfs_mutex_lock_safe(&journal->j_flush_mutex, s);
} else if (mutex_trylock(&journal->j_flush_mutex)) {
BUG();
}
@@ -1553,7 +1606,11 @@ static int flush_journal_list(struct super_block *s,
reiserfs_panic(s, "journal-1011",
"cn->bh is NULL");
}
+
+ reiserfs_write_unlock(s);
wait_on_buffer(cn->bh);
+ reiserfs_write_lock(s);
+
if (!cn->bh) {
reiserfs_panic(s, "journal-1012",
"cn->bh is NULL");
@@ -1973,11 +2030,19 @@ static int do_journal_release(struct reiserfs_transaction_handle *th,
reiserfs_mounted_fs_count--;
/* wait for all commits to finish */
cancel_delayed_work(&SB_JOURNAL(sb)->j_work);
+
+ /*
+ * We must release the write lock here because
+ * the workqueue job (flush_async_commit) needs this lock
+ */
+ reiserfs_write_unlock(sb);
flush_workqueue(commit_wq);
+
if (!reiserfs_mounted_fs_count) {
destroy_workqueue(commit_wq);
commit_wq = NULL;
}
+ reiserfs_write_lock(sb);
free_journal_ram(sb);
@@ -2243,7 +2308,11 @@ static int journal_read_transaction(struct super_block *sb,
/* read in the log blocks, memcpy to the corresponding real block */
ll_rw_block(READ, get_desc_trans_len(desc), log_blocks);
for (i = 0; i < get_desc_trans_len(desc); i++) {
+
+ reiserfs_write_unlock(sb);
wait_on_buffer(log_blocks[i]);
+ reiserfs_write_lock(sb);
+
if (!buffer_uptodate(log_blocks[i])) {
reiserfs_warning(sb, "journal-1212",
"REPLAY FAILURE fsck required! "
@@ -2964,8 +3033,11 @@ static void queue_log_writer(struct super_block *s)
init_waitqueue_entry(&wait, current);
add_wait_queue(&journal->j_join_wait, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
- if (test_bit(J_WRITERS_QUEUED, &journal->j_state))
+ if (test_bit(J_WRITERS_QUEUED, &journal->j_state)) {
+ reiserfs_write_unlock(s);
schedule();
+ reiserfs_write_lock(s);
+ }
__set_current_state(TASK_RUNNING);
remove_wait_queue(&journal->j_join_wait, &wait);
}
@@ -2982,7 +3054,9 @@ static void let_transaction_grow(struct super_block *sb, unsigned int trans_id)
struct reiserfs_journal *journal = SB_JOURNAL(sb);
unsigned long bcount = journal->j_bcount;
while (1) {
+ reiserfs_write_unlock(sb);
schedule_timeout_uninterruptible(1);
+ reiserfs_write_lock(sb);
journal->j_current_jl->j_state |= LIST_COMMIT_PENDING;
while ((atomic_read(&journal->j_wcount) > 0 ||
atomic_read(&journal->j_jlock)) &&
@@ -3033,7 +3107,9 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th,
if (test_bit(J_WRITERS_BLOCKED, &journal->j_state)) {
unlock_journal(sb);
+ reiserfs_write_unlock(sb);
reiserfs_wait_on_write_block(sb);
+ reiserfs_write_lock(sb);
PROC_INFO_INC(sb, journal.journal_relock_writers);
goto relock;
}
@@ -3506,14 +3582,14 @@ static void flush_async_commits(struct work_struct *work)
struct reiserfs_journal_list *jl;
struct list_head *entry;
- lock_kernel();
+ reiserfs_write_lock(sb);
if (!list_empty(&journal->j_journal_list)) {
/* last entry is the youngest, commit it and you get everything */
entry = journal->j_journal_list.prev;
jl = JOURNAL_LIST_ENTRY(entry);
flush_commit_list(sb, jl, 1);
}
- unlock_kernel();
+ reiserfs_write_unlock(sb);
}
/*
@@ -4041,7 +4117,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
* the new transaction is fully setup, and we've already flushed the
* ordered bh list
*/
- mutex_lock(&jl->j_commit_mutex);
+ reiserfs_mutex_lock_safe(&jl->j_commit_mutex, sb);
/* save the transaction id in case we need to commit it later */
commit_trans_id = jl->j_trans_id;
@@ -4203,10 +4279,10 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
* is lost.
*/
if (!list_empty(&jl->j_tail_bh_list)) {
- unlock_kernel();
+ reiserfs_write_unlock(sb);
write_ordered_buffers(&journal->j_dirty_buffers_lock,
journal, jl, &jl->j_tail_bh_list);
- lock_kernel();
+ reiserfs_write_lock(sb);
}
BUG_ON(!list_empty(&jl->j_tail_bh_list));
mutex_unlock(&jl->j_commit_mutex);