Re: [PATCH 21/22] honor r/w changes at do_remount() time

Anton Altaparmakov
2007-02-10T00:30:09Z

On 9 Feb 2007, at 23:22, Andrew Morton wrote:
> On Fri, 09 Feb 2007 14:53:44 -0800
> Dave Hansen <hansendc@us.ibm.com> wrote:
>
>> This is the core of the read-only bind mount patch set.
>
> Who wants read-only bind mounts, and for what reason?

On our local mirror server (mirrors just under 3TiB worth of stuff)
we hold all data on r/w mounted storage in a private location in the
file tree. (Note the server runs Solaris 10 not Linux or the
following would not be possible at present...)

We then bind mount (i.e. loopback mount on Solaris) various
directories from inside the private paths to various other locations
so for example we create /export/ftp/pub/* where "*" are directories
we want to export via FTP and we do all of those as read-only bind
mounts. This gives us that little bit of extra confidence that no-
one from the outside can cause any writes to happen to our mirrored
data. We do similar for NFS by creating lots of read-only bind
mounts in /* that again point into the private locations.

It would be nice if the Linux box that we have that is a copy/backup
of the Solaris box could do the same rather than have all the bind
mounts be read-write because we need the storage in the private
locations to be writable.

Best regards,

Anton