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Date: Fri, 15 May 2009 07:03:14 +0930 From: Kevin Shanahan <kmshanah@...b.org.au> To: Theodore Tso <tytso@....edu> Cc: Andreas Dilger <adilger@....com>, Alex Tomas <bzzz@....com>, linux-ext4@...r.kernel.org Subject: Re: More ext4 acl/xattr corruption - 4th occurence now On Thu, May 14, 2009 at 05:23:25PM -0400, Theodore Tso wrote: > On Fri, May 15, 2009 at 06:32:45AM +0930, Kevin Shanahan wrote: > > Okay, so now I've booted into 2.6.29.3 + check_block_validity patch + > > short circuit i_cached_extent patch, mounted the fs without > > nodelalloc. I was able to run the full exchange backup without > > triggering the check_block_validity error. > > Great! > > So here's the final fix (it replaces the short circuit i_cached_extent > patch) which I plan to push to Linus. It should be much less of a > performance hit than simply short-circuiting i_cached_extent... > > Thanks so much for helping to find track this down!!! If ever someone > deserved an "Ext4 Baker Street Irregulars" T-shirt, it would be > you.... Hehe, no problem. Will do the final testing shortly (ran out of time this morning, users are back on the system now). Just one little correction to your patch below: > commit 039ed7a483fdcb2dbbc29f00cd0d74c101ab14c5 > Author: Theodore Ts'o <tytso@....edu> > Date: Thu May 14 17:09:37 2009 -0400 > > ext4: Fix race in ext4_inode_info.i_cached_extent > > If one CPU is reading from a file while another CPU is writing to the > same file different locations, there is nothing protecting the > i_cached_extent structure from being used and updated at the same > time. This could potentially cause the wrong location on disk to be > read or written to, including potentially causing the corruption of > the block group descriptors and/or inode table. > > Many thanks to Ken Shannah for helping to track down this problem. ^^^^^^^^^^^ Cheers, Kevin Shanahan. -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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