4.9-stable review patch. If anyone has any objections, please let me know.
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From: Li Dongyang dongyangli@ddn.com
commit fe18d649891d813964d3aaeebad873f281627fbc upstream.
Marking mmp bh dirty before writing it will make writeback pick up mmp block later and submit a write, we don't want the duplicate write as kmmpd thread should have full control of reading and writing the mmp block. Another reason is we will also have random I/O error on the writeback request when blk integrity is enabled, because kmmpd could modify the content of the mmp block(e.g. setting new seq and time) while the mmp block is under I/O requested by writeback.
Signed-off-by: Li Dongyang dongyangli@ddn.com Signed-off-by: Theodore Ts'o tytso@mit.edu Reviewed-by: Andreas Dilger adilger@dilger.ca Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/mmp.c | 1 - 1 file changed, 1 deletion(-)
--- a/fs/ext4/mmp.c +++ b/fs/ext4/mmp.c @@ -48,7 +48,6 @@ static int write_mmp_block(struct super_ */ sb_start_write(sb); ext4_mmp_csum_set(sb, mmp); - mark_buffer_dirty(bh); lock_buffer(bh); bh->b_end_io = end_buffer_write_sync; get_bh(bh);