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authorTheodore Ts'o <tytso@mit.edu>2014-09-04 18:09:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2014-09-04 18:09:22 -0400
commitdc6e8d669cf5cb3ff84707c372c0a2a8a5e80845 (patch)
treea96b09d5670e5f4a502dc246de2d9526a2bb261a
parent754cfed6bbcfdea6afb14f2686f7f8d71e94d4e2 (diff)
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>
-rw-r--r--fs/jbd2/checkpoint.c19
1 files changed, 5 insertions, 14 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 18c7a8d3da13..90d6091d7e18 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -96,15 +96,8 @@ static int __try_to_free_cp_buf(struct journal_head *jh)
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 @@ int jbd2_log_do_checkpoint(journal_t *journal)
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 @@ restart:
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 @@ restart2:
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 @@ restart2:
* 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);