linux-ext4 - Re: [PATCH 4/4] ext4: fix end of region partial cluster handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Sun, 23 Nov 2014 12:05:08 -0500
From:	Eric Whitney <enwlinux@...il.com>
To:	Theodore Ts'o <tytso@....edu>
Cc:	Eric Whitney <enwlinux@...il.com>, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 4/4] ext4: fix end of region partial cluster handling

The retry occurs at the end of ext4_ext_remove_space where the code loops
back to the top of the function if err == -EAGAIN, leading to another call
to ext4_ext_rm_leaf.  Nothing new needs to be added - we simply want to
avoid using invalid state to decide whether to free a partial cluster (on
occurrence of -EAGAIN), and the existing retry loop will eventually get us
valid state.

(I actually saw this in testing, but it takes a lot of runs to get there.)

Sorry if I edited down my comment a little too far - I'd be happy to beef
that up if desired.

Thanks,
Eric

* Theodore Ts'o <tytso@....edu>:
> On Fri, Nov 21, 2014 at 09:59:04AM -0500, Eric Whitney wrote:
> > ext4_ext_remove_space() can incorrectly free a partial_cluster if
> > EAGAIN is encountered while truncating or punching.  Extent removal
> > should be retried in this case.
> 
> I don't see anything in the patch below which retries the extent
> removal; am I missing something?
> 
> Thanks,
> 
> 						- Ted
--
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