linux-kernel - [PATCH 2/2] ext4: do not left pages locked in ext4

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Date:	Mon, 13 May 2013 23:08:13 +0400
From:	Alexey Khoroshilov <khoroshilov@...ras.ru>
To:	"Theodore Ts'o" <tytso@....edu>
Cc:	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	spruce-project@...uxtesting.org
Subject: [PATCH 2/2] ext4: do not left pages locked in ext4_writepage()

If call to ext4_init_io_end() is failed under memory pressure,
ext4_writepage() calls redirty_page_for_writepage() but left the page locked.
That leads to a deadlock since it is expected the page is unlocked after writepage().

Found by Linux File System Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>
---
 fs/ext4/inode.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index aeca439..c6bc999 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2250,6 +2250,7 @@ static int ext4_writepage(struct page *page,
 	io_submit.io_end = ext4_init_io_end(inode, GFP_NOFS);
 	if (!io_submit.io_end) {
 		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
 		return -ENOMEM;
 	}
 	ret = ext4_bio_write_page(&io_submit, page, len, wbc);
-- 
1.7.9.5

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