Re: [OpenIndiana-discuss] surprising behaviour of mount
On February 8, 2018 3:30:13 PM UTC, Marc Lobelle wrote: >Hello All, > >Today I had a very curious message when trying to mount a file system >on >a non-empy directory > >cannot mount '/export/home/ml/mydirname': directory is not empty > >Afaik, mounting on a non empty directory has always been allowed: the >original contents is just temporarily hidden. > >mounting was done automatically as a byproduct of > >zpool import -d /dev/lofi szpool > >szpool had been created by > >zpool create -m /export/home/ml/mydirname szpool /dev/lofi/1 > >Is there a good reason to prohibit mounting on a non-empty directory in > >this case ? Is there a way to avoid this constraint ? > >Thanks > > >Marc > > > > > >___ >openindiana-discuss mailing list >openindiana-discuss@openindiana.org >https://openindiana.org/mailman/listinfo/openindiana-discuss Clarifying bits WRT my earlier detailed reply: >Afaik, mounting on a non empty directory has always been allowed: the original >contents is just temporarily hidden. Yes for 'mount', no for 'zfs mount' > mounting was done automatically as a byproduct of > zpool import -d /dev/lofi szpool This implies a 'zfs mount', so... Jim -- Typos courtesy of K-9 Mail on my Android ___ openindiana-discuss mailing list openindiana-discuss@openindiana.org https://openindiana.org/mailman/listinfo/openindiana-discuss
Re: [OpenIndiana-discuss] surprising behaviour of mount
On February 8, 2018 4:42:57 PM UTC, Peter Tribble wrote: >On Thu, Feb 8, 2018 at 3:30 PM, Marc Lobelle > >wrote: > >> Hello All, >> >> Today I had a very curious message when trying to mount a file system >on a >> non-empy directory >> >> cannot mount '/export/home/ml/mydirname': directory is not empty >> >> Afaik, mounting on a non empty directory has always been allowed: the >> original contents is just temporarily hidden. >> > >zfs has always refused to mount over a non-empty directory by default > > >> mounting was done automatically as a byproduct of >> >> zpool import -d /dev/lofi szpool >> >> szpool had been created by >> >> zpool create -m /export/home/ml/mydirname szpool /dev/lofi/1 >> >> Is there a good reason to prohibit mounting on a non-empty directory >in >> this case ? > > >It's to stop you making mistakes. > > >> Is there a way to avoid this constraint ? >> > >'zfs mount -O' will override the non-empty check. Hi, IIRC one of the rationales is that if you have several pools and import them at once (not in sequential predefined order) and they define parts of the same namespace, you can end up with some datasets "overshadowing" others - unless they are mounted into empty locations (e.g. no empty - or full - dirs there with someone else's mountpoints). So to ensure predictability, this check is there and should stay by default. To override it there are mount options (for `mount -F zfs` forever - so you could use it for rootfs bits in /etc/vfstab for example, and `zfs mount` more recently I guess). I campaigned for a dataset property to this effect (so e.g. /var/tmp can overshadow a non-empty location always on my boxes), not sure it was made by anyone. Also note that you can protect mountpoints from getting written into with native (non-GNU) chmod: /bin/chmod -S+ci /var/tmp for example. Of course, do it on the parent dataset's empty directory - before anything is mounted into that point. Note this won't work in Solaris 10 (last Sun 10u8 at least). To make ordered pool imports, see my wiki articles and github repo for wrapping pools into SMF services so you can order dependencies between them (and other services that need their data, e.g. SMF-wrapped zones whose roots or data live on such a pool). Hope this helps, Jim Klimov -- Typos courtesy of K-9 Mail on my Android ___ openindiana-discuss mailing list openindiana-discuss@openindiana.org https://openindiana.org/mailman/listinfo/openindiana-discuss
Re: [OpenIndiana-discuss] surprising behaviour of mount
On Thu, Feb 08, 2018 at 04:42:57PM +, Peter Tribble wrote: > It's to stop you making mistakes. And allow you to do different mistakes. -- +---+ | Marcel Telka e-mail: mar...@telka.sk | |homepage: http://telka.sk/ | |jabber: mar...@jabber.sk | +---+ ___ openindiana-discuss mailing list openindiana-discuss@openindiana.org https://openindiana.org/mailman/listinfo/openindiana-discuss
Re: [OpenIndiana-discuss] surprising behaviour of mount
On Thu, Feb 08, 2018 at 04:30:13PM +0100, Marc Lobelle wrote: > Is there a good reason to prohibit mounting on a non-empty directory in this > case ? IMHO, no. > Is there a way to avoid this constraint ? Some suggestions are here: https://www.illumos.org/issues/5579 -- +---+ | Marcel Telka e-mail: mar...@telka.sk | |homepage: http://telka.sk/ | |jabber: mar...@jabber.sk | +---+ ___ openindiana-discuss mailing list openindiana-discuss@openindiana.org https://openindiana.org/mailman/listinfo/openindiana-discuss
Re: [OpenIndiana-discuss] surprising behaviour of mount
On Thu, Feb 8, 2018 at 3:30 PM, Marc Lobelle wrote: > Hello All, > > Today I had a very curious message when trying to mount a file system on a > non-empy directory > > cannot mount '/export/home/ml/mydirname': directory is not empty > > Afaik, mounting on a non empty directory has always been allowed: the > original contents is just temporarily hidden. > zfs has always refused to mount over a non-empty directory by default > mounting was done automatically as a byproduct of > > zpool import -d /dev/lofi szpool > > szpool had been created by > > zpool create -m /export/home/ml/mydirname szpool /dev/lofi/1 > > Is there a good reason to prohibit mounting on a non-empty directory in > this case ? It's to stop you making mistakes. > Is there a way to avoid this constraint ? > 'zfs mount -O' will override the non-empty check. -- -Peter Tribble http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/ ___ openindiana-discuss mailing list openindiana-discuss@openindiana.org https://openindiana.org/mailman/listinfo/openindiana-discuss
