[Virtio-fs] Deleting files when using NFS as a shared folder

[Gal Hammer]

On Mon, 2 Aug 2021 at 13:36, Dr. David Alan Gilbert <dgilbert at redhat.com>
wrote:

> * Gal Hammer (ghammer at redhat.com) wrote:
> > Hello,
> >
> > When using NFS as a shared folder (mount type nfs4) with a Linux guest I
> > have the following issue:
> >
> > Guest:
> > $ ls -la /mnt/shared
> > total 8
> > drwxr-xrwx.  2  135  135 4096 Aug  2 13:08 .
> > dr-xr-xr-x. 17 root   root    224 May 23 10:58 ..
> > -rw-r--rw-.  1  135  135   27 Aug  2 13:07 readme.txt
> >
> > Host:
> > $ rm readme.txt
> >
> > Guest:
> > $ ls -la /mnt/shared
> > total 8
> > drwxr-xrwx.  2  135  135 4096 Aug  2 13:10 .
> > dr-xr-xr-x. 17 root   root    224 May 23 10:58 ..
> > -rw-r--rw-.  1  135  135   27 Aug  2 13:07 .nfs0000000001b600d000000005
> >
> > Guest:
> > $ cat /mnt/shared/readme.txt
> > This is a readme.txt file.
> >
> > So it seems that the virtiofsd has a reference to the file which the
> guest
> > is not aware of and is unable to send a FUSE_FORGET message. This results
> > in a file not actually deleted (renamed to .nfsXXX) and is still
> accessible
> > by the guest.
> >
> > I have a similar problem when deleting a file from a Windows guest side.
> > The FUSE_READDIR(PLUS) commands add a reference count to files which the
> OS
> > doesn't have a file context for. However I was able to solve it (for
> now?)
> > by keeping track of returned files' inodes.
> >
> > Is this behaviour current and by design?
>
> Current problem, not really by design; the problem is the O_PATH files
> that we have open for the inodes.  I thought if the guest sent the
> forget for the file then it got closed.
>

So if I understand then sending forget message for each inode returned by
readdir won't solve the problem because you need the open files for inodes?

Thanks,

    Gal.


>
> Dave
>
>
> > Thanks,
> >
> >     Gal.
>
> > _______________________________________________
> > Virtio-fs mailing list
> > Virtio-fs at redhat.com
> > https://listman.redhat.com/mailman/listinfo/virtio-fs
>
> --
> Dr. David Alan Gilbert / dgilbert at redhat.com / Manchester, UK
>
>
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