linux-ext4 - Re: More ext4 acl/xattr corruption

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Message-ID: <4A0D66F5.2090204@redhat.com>
Date:	Fri, 15 May 2009 07:58:29 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	Theodore Tso <tytso@....edu>
CC:	Kevin Shanahan <kmshanah@...b.org.au>,
	Andreas Dilger <adilger@....com>, Alex Tomas <bzzz@....com>,
	linux-ext4@...r.kernel.org
Subject: Re: More ext4 acl/xattr corruption - 4th occurence now

Theodore Tso wrote:
> On Thu, May 14, 2009 at 08:21:05PM -0500, Eric Sandeen wrote:
>> it should lay out a 4g file in random 1m direct IOs to fragment it and
>> get a lot of extents, then launch 2 threads, one each doing random reads
>> and random writes of that same file.
>>
>> I can't make this trip it, though ...
> 
> If all of the blocks are in the page cache, you won't end up calling
> ext4_get_blocks().  Try adding a shell script which runs in parallel
> doing a "while /bin/true ; do sleep 1; echo 3 > /proc/sys/vm/drop_cache; done".
> 
> 							- Ted

I made sure it was a big enough file, and consumed enough memory on the
system before the test, that the entire file couldn't fit in memory.

I can try doing the dropping in the bg ... but it should have been going
to disk already.

-Eric
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