jbd2: don't call get_bh() before calling __jbd2_journal_remove_checkpoint()
The __jbd2_journal_remove_checkpoint() doesn't require an elevated
b_count; indeed, until the jh structure gets released by the call to
jbd2_journal_put_journal_head(), the bh's b_count is elevated by
virtue of the existence of the jh structure.
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 18c7a8d..90d6091 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -96,15 +96,8 @@
if (jh->b_transaction == NULL && !buffer_locked(bh) &&
!buffer_dirty(bh) && !buffer_write_io_error(bh)) {
- /*
- * Get our reference so that bh cannot be freed before
- * we unlock it
- */
- get_bh(bh);
JBUFFER_TRACE(jh, "remove from checkpoint list");
ret = __jbd2_journal_remove_checkpoint(jh) + 1;
- BUFFER_TRACE(bh, "release");
- __brelse(bh);
}
return ret;
}
@@ -216,7 +209,7 @@
struct buffer_head *bh;
transaction_t *transaction;
tid_t this_tid;
- int result, batch_count = 0, done = 0;
+ int result, batch_count = 0;
jbd_debug(1, "Start checkpoint\n");
@@ -291,11 +284,9 @@
if (!buffer_dirty(bh)) {
if (unlikely(buffer_write_io_error(bh)) && !result)
result = -EIO;
- get_bh(bh);
BUFFER_TRACE(bh, "remove from checkpoint");
__jbd2_journal_remove_checkpoint(jh);
spin_unlock(&journal->j_list_lock);
- __brelse(bh);
goto retry;
}
/*
@@ -338,12 +329,12 @@
transaction->t_tid != this_tid)
goto out;
- while (!done && transaction->t_checkpoint_io_list) {
+ while (transaction->t_checkpoint_io_list) {
jh = transaction->t_checkpoint_io_list;
bh = jh2bh(jh);
- get_bh(bh);
if (buffer_locked(bh)) {
spin_unlock(&journal->j_list_lock);
+ get_bh(bh);
wait_on_buffer(bh);
/* the journal_head may have gone by now */
BUFFER_TRACE(bh, "brelse");
@@ -359,8 +350,8 @@
* know that it has been written out and so we can
* drop it from the list
*/
- done = __jbd2_journal_remove_checkpoint(jh);
- __brelse(bh);
+ if (__jbd2_journal_remove_checkpoint(jh))
+ break;
}
out:
spin_unlock(&journal->j_list_lock);