Messages in this thread |  | | | Date | Mon, 8 Jun 2009 12:57:52 -0700 | | From | Valerie Aurora <> | | Subject | Re: [PATCH 00/32] VFS based Union Mount (V3) |
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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.
> 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.
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.
-VAL
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