linux-ext4 - Re: [PATCH 1/4] fs: split update_time() into update_time() and write

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: <20141124155658.GA31339@thunk.org>
Date:	Mon, 24 Nov 2014 10:56:58 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	Christoph Hellwig <hch@...radead.org>
Cc:	linux-fsdevel@...r.kernel.org,
	Ext4 Developers List <linux-ext4@...r.kernel.org>,
	xfs@....sgi.com, linux-btrfs@...r.kernel.org
Subject: Re: [PATCH 1/4] fs: split update_time() into update_time() and
 write_time()

On Mon, Nov 24, 2014 at 07:21:01AM -0800, Christoph Hellwig wrote:
> On Fri, Nov 21, 2014 at 02:59:21PM -0500, Theodore Ts'o wrote:
> > We needed to preserve update_time() because btrfs wants to have a
> > special btrfs_root_readonly() check; otherwise we could drop the
> > update_time() inode operation entirely.
> 
> Can't btrfs just set the immutable flag on every inode that is read
> when the root has the BTRFS_ROOT_SUBVOL_RDONLY flag?  That would
> cut down the places that need this check to the ioctl path so that
> we prevent users from clearling the immutable flag.

Sounds like a good plan to me, although I'm not sure I understand how
BTRFS_ROOT_SUBVOL_RDONLY flag works, since I would have thought there
are all sorts of places in the VFS layer where it is currently
checking MS_RDONLY and MNT_READONLY and _not_ checking
BTRFS_ROOT_SUBVOL_RDONLY isn't causing other problems.

But unless there's something more subtle going on, it would seem to me
that setting the immutable flag on each inode would be a better way to
go in any case.

					- 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