| Message ID | 1461015341-20153-6-git-send-email-jack@suse.cz (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 86b0624e42d0 |
| Headers | show |
On Mon, Apr 18, 2016 at 11:35:28PM +0200, Jan Kara wrote: > Currently ext2 zeroes any data blocks allocated for DAX inode however it > still returns them as BH_New. Thus DAX code zeroes them again in > dax_insert_mapping() which can possibly overwrite the data that has been > already stored to those blocks by a racing dax_io(). Avoid marking > pre-zeroed buffers as new. > > Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 6bd58e6ff038..1f07b758b968 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -745,11 +745,11 @@ static int ext2_get_blocks(struct inode *inode, mutex_unlock(&ei->truncate_mutex); goto cleanup; } - } + } else + set_buffer_new(bh_result); ext2_splice_branch(inode, iblock, partial, indirect_blks, count); mutex_unlock(&ei->truncate_mutex); - set_buffer_new(bh_result); got_it: map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); if (count > blocks_to_boundary)
Currently ext2 zeroes any data blocks allocated for DAX inode however it still returns them as BH_New. Thus DAX code zeroes them again in dax_insert_mapping() which can possibly overwrite the data that has been already stored to those blocks by a racing dax_io(). Avoid marking pre-zeroed buffers as new. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/ext2/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)