linux-ext4 - Re: [PATCH] ext4: add checksum calculation when clearing UNINIT flag

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

Message-ID: <20081107142718.GL25194@skywalker>
Date:	Fri, 7 Nov 2008 19:57:18 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Theodore Tso <tytso@....edu>
Cc:	Frédéric Bohé <frederic.bohe@...l.net>,
	linux-ext4 <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: add checksum calculation when clearing UNINIT
	flag

On Fri, Nov 07, 2008 at 08:52:22AM -0500, Theodore Tso wrote:
> On Fri, Nov 07, 2008 at 11:22:56AM +0100, Frédéric Bohé wrote:
> > From: Frederic Bohe <frederic.bohe@...l.net>
> > 
> > Block group's checksum need to be re-calculated during the
> > initialization of an UNINIT'd group. This fix a race when several
> > threads try to allocate a new inode in an UNINIT'd group.
> 
> This patch looks sane, and so I'll accept it, but there's a higher
> order hiding here ---- why are we initializing the block bitmap in
> ext4_new_inode()?  Sure, *most* of the time where we create a new
> inode, we'll be needing to allocate a new block, but sometimes we
> won't (i.e., when creating a symlink, device file, socket, or a
> zero-length regular file).  

Because when we clear the uninitt_bg flag the kernel expect the block 
bitmap to be correctly indicate blocks containing block
bitmap and inode bitmap as used. If mke2fs didn't do that we would
need to do the same when we remove the uninit_bg flag.


-aneesh
--
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