From: Gabriel de Perthuis <g2p.code@gmail.com>
To: linux-btrfs@vger.kernel.org
Subject: Re: Two identical copies of an image mounted result in changes to both images if only one is modified
Date: Thu, 20 Jun 2013 10:41:53 +0000 (UTC) [thread overview]
Message-ID: <kpum9h$ei7$2@ger.gmane.org> (raw)
In-Reply-To: 20130620103404.GN11290@carfax.org.uk
>> Instead of redirecting to a different block device, Btrfs could and
>> should refuse to mount an already-mounted superblock when the block
>> device doesn't match, somewhere in or below btrfs_mount. Registering
>> extra, distinct superblocks for an already mounted raid is a different
>> matter, but that isn't done through the mount syscall anyway.
>
> The problem here is that you could quite legitimately mount
> /dev/sda (with UUID=AA1234) on, say, /mnt/fs-a, and /dev/sdb (with
> UUID=AA1234) on /mnt/fs-b -- _provided_ that /dev/sda and /dev/sdb are
> both part of the same filesystem. So you can't simply prevent mounting
> based on the device that the mount's being done with.
Okay. The check should rely on a list of known block devices
for a given filesystem uuid.
next prev parent reply other threads:[~2013-06-20 10:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-20 8:47 Two identical copies of an image mounted result in changes to both images if only one is modified Clemens Eisserer
2013-06-20 9:11 ` Fajar A. Nugraha
2013-06-20 9:16 ` Hugo Mills
2013-06-20 10:22 ` Gabriel de Perthuis
2013-06-20 10:34 ` Hugo Mills
2013-06-20 10:41 ` Gabriel de Perthuis [this message]
2013-06-20 10:56 ` Hugo Mills
2013-06-20 13:22 ` Kevin O'Kelley
2013-06-20 13:28 ` Hugo Mills
2013-06-20 13:29 ` Gabriel
2013-06-20 13:32 ` Hugo Mills
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