2014-04-09 13:55:04

by Namjae Jeon

[permalink] [raw]
Subject: [PATCH v2] ext4: fix shared/002 and 004 fail issue in xfstests

From: Namjae Jeon <[email protected]>

When mounting ext4 with data=journal option, xfstest shared/002 and
shared/004 are currently failing as checksum computed for testfile
does not match with the checksum computed in other journal modes.
In case of data=journal mode, a call to filemap_write_and_wait_range
will not flush anything to disk as buffers are not marked dirty in
write_end. In collapse range this call is followed by a call to
truncate_pagecache_range. Due to this, when checksum is computed,
a portion of file is re-read from disk which replace valid data with
NULL bytes and hence the reason for the difference in checksum.

Calling ext4_force_commit before filemap_write_and_wait_range solves
the issue as it will mark the buffers dirty during commit transaction
which can be later synced by a call to filemap_write_and_wait_range.

Signed-off-by: Namjae Jeon <[email protected]>
Signed-off-by: Ashish Sangwan <[email protected]>
---
fs/ext4/extents.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 243a02e..dc9333f 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -5375,6 +5375,13 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len)
punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb);
punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb);

+ /* Call ext4_force_commit to flush all data in case of data=journal. */
+ if (ext4_should_journal_data(inode)) {
+ ret = ext4_force_commit(inode->i_sb);
+ if (ret)
+ return ret;
+ }
+
/* Write out all dirty pages */
ret = filemap_write_and_wait_range(inode->i_mapping, offset, -1);
if (ret)
--
1.7.9.5



2014-04-11 02:59:42

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH v2] ext4: fix shared/002 and 004 fail issue in xfstests

On Wed, Apr 09, 2014 at 10:54:29PM +0900, Namjae Jeon wrote:
> From: Namjae Jeon <[email protected]>
>
> When mounting ext4 with data=journal option, xfstest shared/002 and
> shared/004 are currently failing as checksum computed for testfile
> does not match with the checksum computed in other journal modes.
> In case of data=journal mode, a call to filemap_write_and_wait_range
> will not flush anything to disk as buffers are not marked dirty in
> write_end. In collapse range this call is followed by a call to
> truncate_pagecache_range. Due to this, when checksum is computed,
> a portion of file is re-read from disk which replace valid data with
> NULL bytes and hence the reason for the difference in checksum.
>
> Calling ext4_force_commit before filemap_write_and_wait_range solves
> the issue as it will mark the buffers dirty during commit transaction
> which can be later synced by a call to filemap_write_and_wait_range.
>
> Signed-off-by: Namjae Jeon <[email protected]>
> Signed-off-by: Ashish Sangwan <[email protected]>

Thanks, applied.

- Ted