umount(8) failure

[Jukka Salmi <j+nbsd%2008.salmi.ch@localhost>]

Hello,

I noticed this regression some months (?) ago but haven't been able
to find the source of the problem...

Unmounting a file system fails with EBUSY if the call to umount is
immediately following another call to umount and the mount point passed
to the first umount call is a directory within the second umount call's
file system (it doesn't matter whether there is a file system mounted
on that first mount point or not). Waiting for some tenths of a second
between the two umount calls usually works around this problem:

        $ mount -t null /var /mnt/tmp
        $ umount /mnt/tmp/log; umount /mnt/tmp
        umount: /mnt/tmp/log: not currently mounted
        umount: /mnt/tmp: Device busy
        $ umount /mnt/tmp/log; sleep 1; umount /mnt/tmp
        umount: /mnt/tmp/log: not currently mounted
        $ 

This is on a 4.99.65 i386 system; is anybody able to reproduce this?


Regards, Jukka

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