Thread (2 messages) 2 messages, 2 authors, 2010-08-01

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

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
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