linux-ext4 - Re: [PATCH] blkid: optimize dm_device_is

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20080826200028.GA29936@mit.edu>
Date:	Tue, 26 Aug 2008 16:00:28 -0400
From:	Theodore Tso <tytso@....edu>
To:	Andreas Dilger <adilger@....com>
Cc:	Karel Zak <kzak@...hat.com>, linux-ext4@...r.kernel.org,
	Eric Sandeen <sandeen@...hat.com>, mbroz@...hat.com,
	agk@...hat.com
Subject: Re: [PATCH] blkid: optimize dm_device_is_leaf() usage

On Tue, Aug 26, 2008 at 01:44:45PM -0600, Andreas Dilger wrote:
> On Aug 26, 2008  10:47 -0400, Theodore Ts'o wrote:
> > I don't think you mean multipath support in terms of where there are
> > multiple paths to the same physical device ala fiber channel, but
> > rather where are multiple devices which are built on each other,
> > right?  So where /dev/sda is used to create the LVM PV's, and so on,
> > right?
> 
> No, in fact DM has actual mutliple-paths-to-the-same-device support,
> via "dm-multipath".

Well, *that* we have, as long as the parent devices are real
(non-devicemapper) devices.

So if /dev/sdc and /dev/sdg are both paths to the same filesystem, and
dm-multipath has created /dev/mapper/filesystem as the multipath
device to that filesystem, any devices with /dev/mapper have priority
over non-dm devices, so /dev/mapper/filesystem will get returned
first.

					- 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