On Tue, Jun 09, 2009 at 12:44:06AM +0200, Jan Rekorajski wrote: > On Mon, 08 Jun 2009, Valerie Aurora wrote: > > > On Thu, May 21, 2009 at 02:54:19PM +0200, Jan Rekorajski wrote: > > > On Mon, 18 May 2009, Jan Blunck wrote: > > > > > > > Here is another post of the VFS based union mount implementation. > > > > > > Is there any chance this will support NFS? I can union-mount tmpfs over > > > > NFS as the read-only layer ought to work. NFS as the read-write layer > > is still up in the air. > > As I don't need rw NFS, i didn't even try that :) > > > > nfs mounted fs, but if I try to mount --union two NFS filesystems I > > > always get -EBUSY on second mount on the same mountpoint. > > > > > > Something along these lines: > > > > > > doesn't matter if I use --union on first mount, the result is always the > > > same. > > > > > > mount <--union> -t nfs server:/export/system /mnt > > > OK > > > mount --union -t nfs server:/export/profile /mnt > > > mount.nfs: /mnt is busy or already mounted > > > > > > I patched mount.nfs so it knows about MS_UNION, and strace shows me that > > > it passes that flag to kernel. > > > > FYI, using --union on the first mount will make it union with the > > local directory below it. The --union option is not needed when you > > mount the lower read-only layer. > > Thanks for clarification. > > > You'll get -EBUSY on the second mount of any NFS file system over > > another - try it again with the --union flag. Support for NFS on NFS > > union mount would have to change this. > > I did just that, --union didn't change standard NFS behaviour. Er, excuse me - I mean to type "try it again WITHOUT the --union flag." My apologies! > > mount -t nfs server:/export/system /mnt > mount --union -t nfs server:/export/profile /mnt > mount.nfs: /mnt is busy or already mounted > > I did an experiment by using different IP of the server (same machine) > when mounting the second fs, mount worked then, but 'ls -1 /mnt' oopsed. > I can reproduce this and send you the oops next week. Interesting! Does this happen without the --union flag? -VAL -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
