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  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]
Date:	Tue, 12 Apr 2011 15:39:33 -0500
From:	Eric Sandeen <>
To:	Johann Lombardi <>
CC:, Andreas Dilger <>
Subject: Re: [PATCH] ext4: add support for multiple mount protection

On 4/12/11 1:04 PM, Johann Lombardi wrote:
> Prevent an ext4 filesystem from being mounted multiple times.
> A sequence number is stored on disk and is periodically updated (every 5
> seconds by default) by a mounted filesystem.
> At mount time, we now wait for s_mmp_update_interval seconds to make sure
> that the MMP sequence does not change.
> In case of failure, the nodename, bdevname and the time at which the MMP
> block was last updated is displayed.
> Signed-off-by: Andreas Dilger <>
> Signed-off-by: Johann Lombardi <>
> ---
>  fs/ext4/ext4.h  |   56 ++++++++-
>  fs/ext4/super.c |  363 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 416 insertions(+), 3 deletions(-)

There was a lot of skepticism about this last time, and I imagine there still is...

400 new lines of kernel code for this, and if the other machine is hung up for 5 seconds and doesn't update, it can still be multiply-mounted anyway, right?

BUG: soft lockup - CPU#0 stuck for 10s! anyone?  :(

I don't see the value in it for upstream ext4, but then hey, ext4 rarely meets a feature it doesn't like ;)

To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists