[PATCH] ext4: pair trace_ext4_writepages & trace_ext4_writepages_result

[Ming Lei <ming.lei@canonical.com>]

Pair the two trace events to make troubeshooting writepages
easier, and it should be more convinient to write a simple script
to parse the traces.

Cc: Ted Tso <tytso@mit.edu>
Cc: linux-ext4@vger.kernel.org
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 fs/ext4/inode.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 32beaa4..0ad73d4 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2420,16 +2420,15 @@ static int ext4_writepages(struct address_space *mapping,
 	 * because that could violate lock ordering on umount
 	 */
 	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
-		return 0;
+		goto out_writepages;
 
 	if (ext4_should_journal_data(inode)) {
 		struct blk_plug plug;
-		int ret;
 
 		blk_start_plug(&plug);
 		ret = write_cache_pages(mapping, wbc, __writepage, mapping);
 		blk_finish_plug(&plug);
-		return ret;
+		goto out_writepages;
 	}
 
 	/*
@@ -2442,8 +2441,10 @@ static int ext4_writepages(struct address_space *mapping,
 	 * *never* be called, so if that ever happens, we would want
 	 * the stack trace.
 	 */
-	if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
-		return -EROFS;
+	if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED)) {
+		ret = -EROFS;
+		goto out_writepages;
+	}
 
 	if (ext4_should_dioread_nolock(inode)) {
 		/*
-- 
1.7.9.5