[PATCH 2/2] jbd2: optimize jbd2_log_do_checkpoint() a bit

[Theodore Ts'o <tytso@mit.edu>]

From: Jan Kara <jack@suse.cz>

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>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/jbd2/checkpoint.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index cb6e17c..7713f94 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -289,9 +289,10 @@ restart:
 			if (unlikely(buffer_write_io_error(bh)) && !result)
 				result = -EIO;
 			BUFFER_TRACE(bh, "remove from checkpoint");
-			__jbd2_journal_remove_checkpoint(jh);
-			spin_unlock(&journal->j_list_lock);
-			goto retry;
+			if (__jbd2_journal_remove_checkpoint(jh))
+				/* The transaction was released; we're done */
+				goto out;
+			continue;
 		}
 		/*
 		 * Important: we are about to write the buffer, and
-- 
2.1.0