2008-07-25 22:56:38

by Andrew Morton

[permalink] [raw]
Subject: - ext3-dont-read-inode-block-if-the-buffer-has-a-write-error.patch removed from -mm tree

The patch titled
ext3: don't read inode block if the buffer has a write error
has been removed from the -mm tree. Its filename was

This patch was dropped because it was merged into mainline or a subsystem tree

The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/

Subject: ext3: don't read inode block if the buffer has a write error
From: Hidehiro Kawai <[email protected]>

A transient I/O error can corrupt inode data. Here is the scenario:

(1) update inode_A at the block_B
(2) pdflush writes out new inode_A to the filesystem, but it results
in write I/O error, at this point, BH_Uptodate flag of the buffer
for block_B is cleared and BH_Write_EIO is set
(3) create new inode_C which located at block_B, and
__ext3_get_inode_loc() tries to read on-disk block_B because the
buffer is not uptodate
(4) if it can read on-disk block_B successfully, inode_A is
overwritten by old data

This patch makes __ext3_get_inode_loc() not read the inode block if the
buffer has BH_Write_EIO flag. In this case, the buffer should have the
latest information, so setting the uptodate flag to the buffer (this
avoids WARN_ON_ONCE() in mark_buffer_dirty().)

According to this change, we would need to test BH_Write_EIO flag for the
error checking. Currently nobody checks write I/O errors on metadata
buffers, but it will be done in other patches I'm working on.

Signed-off-by: Hidehiro Kawai <[email protected]>
Cc: sugita <[email protected]>
Cc: Satoshi OSHIMA <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

fs/ext3/inode.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff -puN fs/ext3/inode.c~ext3-dont-read-inode-block-if-the-buffer-has-a-write-error fs/ext3/inode.c
--- a/fs/ext3/inode.c~ext3-dont-read-inode-block-if-the-buffer-has-a-write-error
+++ a/fs/ext3/inode.c
@@ -2521,6 +2521,16 @@ static int __ext3_get_inode_loc(struct i
if (!buffer_uptodate(bh)) {
+ /*
+ * If the buffer has the write error flag, we have failed
+ * to write out another inode in the same block. In this
+ * case, we don't have to read the block because we may
+ * read the old inode data successfully.
+ */
+ if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
+ set_buffer_uptodate(bh);
if (buffer_uptodate(bh)) {
/* someone brought it uptodate while we waited */

Patches currently in -mm which might be from [email protected] are