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>
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 7f5451c..beacce1 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -237,8 +237,6 @@
} 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 @@
*/
if (!partial_write)
SetPageUptodate(page);
+
+ put_io_page(io_end->pages[i]);
}
io_end->num_io_pages = 0;
inode = io_end->inode;