Subject : [2.6.32-rc4] + EXT4 corruption Submitter : Shawn Starr <shawn.starr@rogers.com> Date : 2009-10-13 2:07 References : http://marc.info/?l=linux-kernel&m=125539997508256&w=4 Handled-By : Theodore Tso <tytso@mit.edu> Notify-Also : Andy Lutomirski <luto@mit.edu> This entry is being used for tracking a regression from 2.6.31. Please don't close it until the problem is fixed in the mainline.
On Thursday 29 October 2009, Andrew Lutomirski wrote: > On Mon, Oct 26, 2009 at 2:55 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote: > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.31. Please verify if it still should be listed and let me know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=14472 > > Subject : EXT4 corruption > > Submitter : Shawn Starr <shawn.starr@rogers.com> > > Date : 2009-10-13 2:07 (14 days old) > > References : http://marc.info/?l=linux-kernel&m=125539997508256&w=4 > > Handled-By : Theodore Tso <tytso@mit.edu> > > > > > This but is *not* fixed. I just triggered it a few minutes ago by > abusing i915 and drm, which caused a panic. This is slightly newer > than 2.6.32-rc5, with a couple of i915 bugfixes thrown in. > > Photos are here: > http://web.mit.edu/luto/www/ext4_crashphotos/ > > This is a very nasty regression, for obvious reasons.
I looked at the fsck pics - I have gone through this a few days ago. Aneesh suggested to apply the below patch and after applying it and crashing the machine couple times I have not observed the corruption. So I have reason to hope this patch below on top of today's git should improve things. Please try. commit a8836b1d6f92273e001012c7705ae8f4c3d5fb65 Author: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Date: Tue Oct 27 15:36:38 2009 +0530 ext4: discard preallocation during truncate We need to make sure when we drop and reacquire the inode's i_data_sem we discard the inode preallocation. Otherwise we could have blocks marked as free in bitmap but still belonging to prealloc space. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5c5bc5d..a1ef1c3 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -209,6 +209,12 @@ static int try_to_extend_transaction(handle_t *handle, struct inode *inode) up_write(&EXT4_I(inode)->i_data_sem); ret = ext4_journal_restart(handle, blocks_for_truncate(inode)); down_write(&EXT4_I(inode)->i_data_sem); + /* + * We have dropped i_data_sem. So somebody else could have done + * block allocation. So discard the prealloc space created as a + * part of block allocation + */ + ext4_discard_preallocations(inode); return ret; }
Lest champagne break out too early, I have still seen corruption with this patch in place, while running my testcase (mentioned in bug #14354) -Eric
On Tuesday 17 November 2009, Andy Lutomirski wrote: > I'm think this was the journal checksumming bug, which is fixed. > > > On Nov 16, 2009, at 5:37 PM, "Rafael J. Wysocki" <rjw@sisk.pl> wrote: > > > This message has been generated automatically as a part of a report > > of recent regressions. > > > > The following bug entry is on the current list of known regressions > > from 2.6.31. Please verify if it still should be listed and let me > > know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=14472 > > Subject : EXT4 corruption > > Submitter : Shawn Starr <shawn.starr@rogers.com> > > Date : 2009-10-13 2:07 (35 days old) > > References : http://marc.info/?l=linux-kernel&m=125539997508256&w=4 > > Handled-By : Theodore Tso <tytso@mit.edu>