[PATCH] jbd2: Optimize jbd2_log_do_checkpoint() a bit

Jan Kara
2014-10-10T14:24:10Z

When we discover written out buffer in transaction checkpoint list we
don't have to recheck validity of a transaction. Either this is the last
buffer in a transaction - and then we are done - or this isn't and then
we can just take another buffer from the checkpoint list without
dropping j_list_lock.

Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/jbd2/checkpoint.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 993a187527f3..3722e2e53638 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -343,12 +343,15 @@ 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;
+ if (__jbd2_journal_remove_checkpoint(jh)) {
+ /*
+ * This was the last buffer attached to the
+ * transaction. We are done.
+ */
+ goto out;
+ }
+ continue;
}
/*
* Important: we are about to write the buffer, and