linux-ext4 - Re: duplicate entries on ext3 when using readdir/readdir64

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Message-ID: <170fa0d20808131421j3e4955dcra611509f1a094547@mail.gmail.com>
Date:	Wed, 13 Aug 2008 17:21:20 -0400
From:	"Mike Snitzer" <snitzer@...il.com>
To:	"Theodore Tso" <tytso@....edu>
Cc:	"Thomas Trauner" <tt@...austria.net>, linux-ext4@...r.kernel.org,
	ext3-users <ext3-users@...hat.com>
Subject: Re: duplicate entries on ext3 when using readdir/readdir64

On Wed, Aug 6, 2008 at 10:07 AM, Theodore Tso <tytso@....edu> wrote:
> On Tue, Aug 05, 2008 at 12:53:51PM +0200, Thomas Trauner wrote:
>> On Fri, 2008-08-01 at 08:16 -0400, Theodore Tso wrote:
>> > On Fri, Aug 01, 2008 at 11:43:40AM +0200, Thomas Trauner wrote:
>> > >
>> > > I have a problem with directories that contain more than 10000 entries
>> > > (Ubuntu 8.04.1) or with more than 70000 entries (RHEL 5.2). If you use
>> > > readdir(3) or readdir64(3) you get one entry twice, with same name and
>> > > inode.
>> > >
>> I made new tests with the code under
>> <http://www.unet.univie.ac.at/~a9100884/readdir.c> on a bunch of freshly
>> generated and empty filesystems, every about 38GB large, of type fat
>> (aborted after about 22000 entries because it took to long), ext2, xfs,
>> jfs and again ext3....
>
> OK, I have a workaroud for you.  It appears there's a kernel bug
> hiding here, since there shouldn't be duplicates returned by readdir()
> even if we have hash collisions.

Ted,

The attached patch has served my employer (IBRIX) well for 2.5 years.
It was only recently, when I re-raised this issue internally based on
this thread, that a co-worker recalled the fix.

regards,
Mike

View attachment "ext3_dx_readdir_hash_collision_fix.patch" of type "text/x-patch" (1400 bytes)