From 17335dcc471199717839b2fa3492ca36f70f1168 Mon Sep 17 00:00:00 2001 From: Dmitry Monakhov Date: Sat, 29 Sep 2012 00:41:21 -0400 Subject: ext4: serialize dio nonlocked reads with defrag workers Inode's block defrag and ext4_change_inode_journal_flag() may affect nonlocked DIO reads result, so proper synchronization required. - Add missed inode_dio_wait() calls where appropriate - Check inode state under extra i_dio_count reference. Reviewed-by: Jan Kara Signed-off-by: Dmitry Monakhov Signed-off-by: "Theodore Ts'o" --- fs/ext4/indirect.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'fs/ext4/indirect.c') diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c index 61f13e57975e..8d849dae8428 100644 --- a/fs/ext4/indirect.c +++ b/fs/ext4/indirect.c @@ -810,11 +810,25 @@ retry: if (unlikely(!list_empty(&ei->i_completed_io_list))) ext4_flush_completed_IO(inode); + /* + * Nolock dioread optimization may be dynamically disabled + * via ext4_inode_block_unlocked_dio(). Check inode's state + * while holding extra i_dio_count ref. + */ + atomic_inc(&inode->i_dio_count); + smp_mb(); + if (unlikely(ext4_test_inode_state(inode, + EXT4_STATE_DIOREAD_LOCK))) { + inode_dio_done(inode); + goto locked; + } ret = __blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block, NULL, NULL, 0); + inode_dio_done(inode); } else { +locked: ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs, ext4_get_block); -- cgit v1.2.3