Re: Request: removal of fs/fs.h/super_block.u to enable partition

Andreas Dilger (adilger@turbolabs.com)
Wed, 19 Sep 2001 17:16:43 -0600


On Sep 19, 2001 22:52 +0100, Alan Cox wrote:
> Apart from the fact that the interface is source level you already can
> distribute, compile and merge file systems without patching the kernel.
>
> It seems to be a user space issue not a kernel one. Your app can amend
> /etc/mtab when it creates and shuts down.

Well, in recent versions of e2fsprogs it prefers to check /proc/mounts
over /etc/mtab to determine if a device is in-use, because the latter
can be incorrect after a crash, and the root filesystem is read-only at
this time. There was recently a bug report about this from Slackware
users, where fsck is run on all of the filesystems before root is
remounted rw. As a result, there is now even extra checking to see if
the devno of the mountpoint == devno of the device, otherwise it assumes
the /etc/mtab entry is bogus.

On most other systems, root is remounted rw before non-root filesystems
are checked, and /etc/mtab could be assumed to be correct, but it will
never be checked if /proc/mounts exists.

Cheers, Andreas

--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

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