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authorMarkus Trippelsdorf <markus@trippelsdorf.de>2010-11-17 21:46:06 -0500
committerTheodore Ts'o <tytso@mit.edu>2010-11-17 21:46:06 -0500
commit08da1193d2c8c7a25d0cef7f85d0b9f1ad7c583a (patch)
tree5a288945b73bc0ea79ca26e556f8061b51a85c1d /fs/ext4/page-io.c
parente53beacd23d9cb47590da6a7a7f6d417b941a994 (diff)
downloadlinux-08da1193d2c8c7a25d0cef7f85d0b9f1ad7c583a.tar.gz
ext4: fix setting random pages PageUptodate
ext4_end_bio calls put_page and kmem_cache_free before calling
SetPageUpdate(). This can result in setting the PageUptodate bit on
random pages and causes the following BUG:

 BUG: Bad page state in process rm  pfn:52e54
 page:ffffea0001222260 count:0 mapcount:0 mapping:          (null) index:0x0
 arch kernel: page flags: 0x4000000000000008(uptodate)

Fix the problem by moving put_io_page() after the SetPageUpdate() call.

Thanks to Hugh Dickins for analyzing this problem.

Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/page-io.c')
-rw-r--r--fs/ext4/page-io.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 7f5451cd1d38..beacce11ac50 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -237,8 +237,6 @@ static void ext4_end_bio(struct bio *bio, int error)
 			} while (bh != head);
 		}
 
-		put_io_page(io_end->pages[i]);
-
 		/*
 		 * If this is a partial write which happened to make
 		 * all buffers uptodate then we can optimize away a
@@ -248,6 +246,8 @@ static void ext4_end_bio(struct bio *bio, int error)
 		 */
 		if (!partial_write)
 			SetPageUptodate(page);
+
+		put_io_page(io_end->pages[i]);
 	}
 	io_end->num_io_pages = 0;
 	inode = io_end->inode;