linux-kernel - [PATCH 1/7] f2fs: avoid needless lock for node pages when fsyncing a file

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Message-Id: <1461629220-16280-1-git-send-email-jaegeuk@kernel.org>
Date:	Mon, 25 Apr 2016 17:06:54 -0700
From:	Jaegeuk Kim <jaegeuk@...nel.org>
To:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-f2fs-devel@...ts.sourceforge.net
Cc:	Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 1/7] f2fs: avoid needless lock for node pages when fsyncing a file

When fsync is called, sync_node_pages finds a proper direct node pages to flush.
But, it locks unrelated direct node pages together unnecessarily.

Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
 fs/f2fs/node.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 095fc2c..cccee50 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1272,10 +1272,14 @@ next_step:
 			 * we should not skip writing node pages.
 			 */
 lock_node:
-			if (ino && ino_of_node(page) == ino)
-				lock_page(page);
-			else if (!trylock_page(page))
+			if (ino) {
+				if (ino_of_node(page) == ino)
+					lock_page(page);
+				else
+					continue;
+			} else if (!trylock_page(page)) {
 				continue;
+			}
 
 			if (unlikely(page->mapping != NODE_MAPPING(sbi))) {
 continue_unlock:
-- 
2.6.3