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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>
This commit is contained in:
Markus Trippelsdorf 2010-11-17 21:46:06 -05:00 committed by Theodore Ts'o
parent e53beacd23
commit 08da1193d2
1 changed files with 2 additions and 2 deletions
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4
fs/ext4/page-io.c
View File

@ -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;