[BusyBox] Endless "umount" corner cases: judgement call time...
aurel at gnuage.org
Fri Aug 5 01:29:23 UTC 2005
On Thu, 4 Aug 2005 08:59:00 -0500
Rob Landley <rob at landley.net> wrote:
> Okay, with 2.6 you can now happily mount the same block device in
> several places and it acts a bit like multiple --bind mounts (they'll
> all share the same superblock so nothing gets corrupted).
> So, if you mount /dev/hda4 in three places and then umount
> /dev/hda4... Does this mean all three places should be unmounted? Or
> just the most recent one? (Note you can specify a directory you want
> unmounted, and this is now a different thing than specifying the
> block devices. Unmounts now always try to work on directories
> because the current internal logic that tries to deal with a --bind
> mount and convert that to a block device is going to get really
> confused. Not that I'm ever quite sure what it expected to do
> umounting an NFS mount or ramfs anyway...)
> Anyway, I'm leaning towards "umount /dev/hda4" umounts all instances
> of hda4, because if you wanted to specify umounting a specific
> directory you've have indicated the directory. But I'd like a show
> of hands about this. (It wasn't an issue back before bind mounts
> existed because you couldn't mount a block device in two places and
> expect it to work back then.)
What util-linux mount version do is just unmounting the most recent one.
Now, wether you want to respect what this kind of "standard" version do
is another question.
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