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authorJeff Mahoney <jeffm@suse.com>2013-08-09 01:34:46 +0400
committerJeff Mahoney <jeffm@suse.de>2013-08-09 01:34:46 +0400
commit278f6679f454bf185a07d9a4ca355b153482d17a (patch)
treeffead073e67cfdc1ddfc3949ebc93c06dcaaab8f /fs/reiserfs/journal.c
parent4c05141df57f4ffc1a9a28f1925434924179bfe4 (diff)
downloadlinux-278f6679f454bf185a07d9a4ca355b153482d17a.tar.xz
reiserfs: locking, handle nested locks properly
The reiserfs write lock replaced the BKL and uses similar semantics. Frederic's locking code makes a distinction between when the lock is nested and when it's being acquired/released, but I don't think that's the right distinction to make. The right distinction is between the lock being released at end-of-use and the lock being released for a schedule. The unlock should return the depth and the lock should restore it, rather than the other way around as it is now. This patch implements that and adds a number of places where the lock should be dropped. Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Diffstat (limited to 'fs/reiserfs/journal.c')
-rw-r--r--fs/reiserfs/journal.c104
1 files changed, 56 insertions, 48 deletions
diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 742fdd4c209a..73feacc49b2e 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -947,9 +947,11 @@ static int reiserfs_async_progress_wait(struct super_block *s)
struct reiserfs_journal *j = SB_JOURNAL(s);
if (atomic_read(&j->j_async_throttle)) {
- reiserfs_write_unlock(s);
+ int depth;
+
+ depth = reiserfs_write_unlock_nested(s);
congestion_wait(BLK_RW_ASYNC, HZ / 10);
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
return 0;
@@ -972,6 +974,7 @@ static int flush_commit_list(struct super_block *s,
struct reiserfs_journal *journal = SB_JOURNAL(s);
int retval = 0;
int write_len;
+ int depth;
reiserfs_check_lock_depth(s, "flush_commit_list");
@@ -1018,12 +1021,12 @@ static int flush_commit_list(struct super_block *s,
* We might sleep in numerous places inside
* write_ordered_buffers. Relax the write lock.
*/
- reiserfs_write_unlock(s);
+ depth = reiserfs_write_unlock_nested(s);
ret = write_ordered_buffers(&journal->j_dirty_buffers_lock,
journal, jl, &jl->j_bh_list);
if (ret < 0 && retval == 0)
retval = ret;
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
BUG_ON(!list_empty(&jl->j_bh_list));
/*
@@ -1043,9 +1046,9 @@ static int flush_commit_list(struct super_block *s,
tbh = journal_find_get_block(s, bn);
if (tbh) {
if (buffer_dirty(tbh)) {
- reiserfs_write_unlock(s);
+ depth = reiserfs_write_unlock_nested(s);
ll_rw_block(WRITE, 1, &tbh);
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
put_bh(tbh) ;
}
@@ -1057,17 +1060,17 @@ static int flush_commit_list(struct super_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);
+ depth = reiserfs_write_unlock_nested(s);
+ __wait_on_buffer(tbh);
+ reiserfs_write_lock_nested(s, depth);
// since we're using ll_rw_blk above, it might have skipped over
// a locked buffer. Double check here
//
/* redundant, sync_dirty_buffer() checks */
if (buffer_dirty(tbh)) {
- reiserfs_write_unlock(s);
+ depth = reiserfs_write_unlock_nested(s);
sync_dirty_buffer(tbh);
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
if (unlikely(!buffer_uptodate(tbh))) {
#ifdef CONFIG_REISERFS_CHECK
@@ -1091,12 +1094,12 @@ 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);
+ depth = reiserfs_write_unlock_nested(s);
if (reiserfs_barrier_flush(s))
__sync_dirty_buffer(jl->j_commit_bh, WRITE_FLUSH_FUA);
else
sync_dirty_buffer(jl->j_commit_bh);
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
/* If there was a write error in the journal - we can't commit this
@@ -1228,15 +1231,16 @@ static int _update_journal_header_block(struct super_block *sb,
{
struct reiserfs_journal_header *jh;
struct reiserfs_journal *journal = SB_JOURNAL(sb);
+ int depth;
if (reiserfs_is_journal_aborted(journal))
return -EIO;
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);
+ depth = reiserfs_write_unlock_nested(sb);
+ __wait_on_buffer(journal->j_header_bh);
+ reiserfs_write_lock_nested(sb, depth);
if (unlikely(!buffer_uptodate(journal->j_header_bh))) {
#ifdef CONFIG_REISERFS_CHECK
reiserfs_warning(sb, "journal-699",
@@ -1254,14 +1258,14 @@ static int _update_journal_header_block(struct super_block *sb,
jh->j_mount_id = cpu_to_le32(journal->j_mount_id);
set_buffer_dirty(journal->j_header_bh);
- reiserfs_write_unlock(sb);
+ depth = reiserfs_write_unlock_nested(sb);
if (reiserfs_barrier_flush(sb))
__sync_dirty_buffer(journal->j_header_bh, WRITE_FLUSH_FUA);
else
sync_dirty_buffer(journal->j_header_bh);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(sb, depth);
if (!buffer_uptodate(journal->j_header_bh)) {
reiserfs_warning(sb, "journal-837",
"IO error during journal replay");
@@ -1341,6 +1345,7 @@ static int flush_journal_list(struct super_block *s,
unsigned long j_len_saved = jl->j_len;
struct reiserfs_journal *journal = SB_JOURNAL(s);
int err = 0;
+ int depth;
BUG_ON(j_len_saved <= 0);
@@ -1495,9 +1500,9 @@ static int flush_journal_list(struct super_block *s,
"cn->bh is NULL");
}
- reiserfs_write_unlock(s);
- wait_on_buffer(cn->bh);
- reiserfs_write_lock(s);
+ depth = reiserfs_write_unlock_nested(s);
+ __wait_on_buffer(cn->bh);
+ reiserfs_write_lock_nested(s, depth);
if (!cn->bh) {
reiserfs_panic(s, "journal-1012",
@@ -1974,6 +1979,7 @@ static int journal_compare_desc_commit(struct super_block *sb,
/* returns 0 if it did not find a description block
** returns -1 if it found a corrupt commit block
** returns 1 if both desc and commit were valid
+** NOTE: only called during fs mount
*/
static int journal_transaction_is_valid(struct super_block *sb,
struct buffer_head *d_bh,
@@ -2073,8 +2079,9 @@ static void brelse_array(struct buffer_head **heads, int num)
/*
** given the start, and values for the oldest acceptable transactions,
-** this either reads in a replays a transaction, or returns because the transaction
-** is invalid, or too old.
+** this either reads in a replays a transaction, or returns because the
+** transaction is invalid, or too old.
+** NOTE: only called during fs mount
*/
static int journal_read_transaction(struct super_block *sb,
unsigned long cur_dblock,
@@ -2208,10 +2215,7 @@ static int journal_read_transaction(struct super_block *sb,
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! "
@@ -2318,12 +2322,13 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev,
/*
** read and replay the log
-** on a clean unmount, the journal header's next unflushed pointer will be to an invalid
-** transaction. This tests that before finding all the transactions in the log, which makes normal mount times fast.
-**
-** After a crash, this starts with the next unflushed transaction, and replays until it finds one too old, or invalid.
-**
+** on a clean unmount, the journal header's next unflushed pointer will
+** be to an invalid transaction. This tests that before finding all the
+** transactions in the log, which makes normal mount times fast.
+** After a crash, this starts with the next unflushed transaction, and
+** replays until it finds one too old, or invalid.
** On exit, it sets things up so the first transaction will work correctly.
+** NOTE: only called during fs mount
*/
static int journal_read(struct super_block *sb)
{
@@ -2501,14 +2506,18 @@ static int journal_read(struct super_block *sb)
"replayed %d transactions in %lu seconds\n",
replay_count, get_seconds() - start);
}
+ /* needed to satisfy the locking in _update_journal_header_block */
+ reiserfs_write_lock(sb);
if (!bdev_read_only(sb->s_bdev) &&
_update_journal_header_block(sb, journal->j_start,
journal->j_last_flush_trans_id)) {
+ reiserfs_write_unlock(sb);
/* replay failed, caller must call free_journal_ram and abort
** the mount
*/
return -1;
}
+ reiserfs_write_unlock(sb);
return 0;
}
@@ -2828,13 +2837,7 @@ int journal_init(struct super_block *sb, const char *j_dev_name,
goto free_and_return;
}
- /*
- * Journal_read needs to be inspected in order to push down
- * the lock further inside (or even remove it).
- */
- reiserfs_write_lock(sb);
ret = journal_read(sb);
- reiserfs_write_unlock(sb);
if (ret < 0) {
reiserfs_warning(sb, "reiserfs-2006",
"Replay Failure, unable to mount");
@@ -2923,9 +2926,9 @@ static void queue_log_writer(struct super_block *s)
add_wait_queue(&journal->j_join_wait, &wait);
set_current_state(TASK_UNINTERRUPTIBLE);
if (test_bit(J_WRITERS_QUEUED, &journal->j_state)) {
- reiserfs_write_unlock(s);
+ int depth = reiserfs_write_unlock_nested(s);
schedule();
- reiserfs_write_lock(s);
+ reiserfs_write_lock_nested(s, depth);
}
__set_current_state(TASK_RUNNING);
remove_wait_queue(&journal->j_join_wait, &wait);
@@ -2943,9 +2946,12 @@ 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);
+ int depth;
+
+ depth = reiserfs_write_unlock_nested(sb);
schedule_timeout_uninterruptible(1);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(sb, depth);
+
journal->j_current_jl->j_state |= LIST_COMMIT_PENDING;
while ((atomic_read(&journal->j_wcount) > 0 ||
atomic_read(&journal->j_jlock)) &&
@@ -2976,6 +2982,7 @@ static int do_journal_begin_r(struct reiserfs_transaction_handle *th,
struct reiserfs_transaction_handle myth;
int sched_count = 0;
int retval;
+ int depth;
reiserfs_check_lock_depth(sb, "journal_begin");
BUG_ON(nblocks > journal->j_trans_max);
@@ -2996,9 +3003,9 @@ 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);
+ depth = reiserfs_write_unlock_nested(sb);
reiserfs_wait_on_write_block(sb);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(sb, depth);
PROC_INFO_INC(sb, journal.journal_relock_writers);
goto relock;
}
@@ -3821,6 +3828,7 @@ void reiserfs_restore_prepared_buffer(struct super_block *sb,
if (test_clear_buffer_journal_restore_dirty(bh) &&
buffer_journal_dirty(bh)) {
struct reiserfs_journal_cnode *cn;
+ reiserfs_write_lock(sb);
cn = get_journal_hash_dev(sb,
journal->j_list_hash_table,
bh->b_blocknr);
@@ -3828,6 +3836,7 @@ void reiserfs_restore_prepared_buffer(struct super_block *sb,
set_buffer_journal_test(bh);
mark_buffer_dirty(bh);
}
+ reiserfs_write_unlock(sb);
}
clear_buffer_journal_prepared(bh);
}
@@ -3911,6 +3920,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
unsigned long jindex;
unsigned int commit_trans_id;
int trans_half;
+ int depth;
BUG_ON(th->t_refcount > 1);
BUG_ON(!th->t_trans_id);
@@ -4116,9 +4126,7 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
next = cn->next;
free_cnode(sb, cn);
cn = next;
- reiserfs_write_unlock(sb);
- cond_resched();
- reiserfs_write_lock(sb);
+ reiserfs_cond_resched(sb);
}
/* we are done with both the c_bh and d_bh, but
@@ -4165,10 +4173,10 @@ static int do_journal_end(struct reiserfs_transaction_handle *th,
* is lost.
*/
if (!list_empty(&jl->j_tail_bh_list)) {
- reiserfs_write_unlock(sb);
+ depth = reiserfs_write_unlock_nested(sb);
write_ordered_buffers(&journal->j_dirty_buffers_lock,
journal, jl, &jl->j_tail_bh_list);
- reiserfs_write_lock(sb);
+ reiserfs_write_lock_nested(sb, depth);
}
BUG_ON(!list_empty(&jl->j_tail_bh_list));
mutex_unlock(&jl->j_commit_mutex);