Re: [PATCH] ext4: fix freeze deadlock under IO
From: Ted Ts'o <tytso@mit.edu>
Date: 2010-08-01 21:41:32
Also in:
dm-devel, linux-fsdevel
From: Ted Ts'o <tytso@mit.edu>
Date: 2010-08-01 21:41:32
Also in:
dm-devel, linux-fsdevel
On Wed, Jun 23, 2010 at 02:37:27PM -0500, Eric Sandeen wrote:
Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks when freezing a filesystem which had active IO; the vfs_check_frozen level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing through. Duh. Changing the test to FREEZE_TRANS should let the normal freeze syncing get through the fs, but still block any transactions from starting once the fs is completely frozen. I tested this by running fsstress in the background while periodically snapshotting the fs and running fsck on the result. I ran into occasional deadlocks, but different ones. I think this is a fine fix for the problem at hand, and the other deadlocky things will need more investigation. Reported-by: Phillip Susi <redacted> Signed-off-by: Eric Sandeen <redacted>
Applied to the ext4 patch queue. Sorry for missing this earier. - Ted