2.6.24-rc3 unable to mount something which should use nohide

2.6.24-rc3 unable to mount something which should use nohide

[Eric Paris]

NFS server "paris" (some 2.6.18 based kernel):

[root@paris ~]# mount | grep storage
/dev/mapper/StorageVG01-LogVol00 on /export/storage type ext3 (rw)
/dev/mapper/KernelVG01-LogVol00 on /export/storage/kernel type ext3 (rw)
[root@paris ~]# cat /etc/exports
/export/storage         *(rw,sync,all_squash,anonuid=500,anongid=500)
/export/storage/kernel  *(rw,sync,all_squash,anonuid=500,anongid=500,nohide)

On my clients x86_64 running an almost clean-from-git 2.6.24-rc3 kernel:

[root@dhcp231-145 ~]# mount -o noatime paris:/export/storage /storage
[root@dhcp231-145 ~]# ls /storage/kernel
ls: cannot access /storage/kernel: Stale NFS file handle

(notice /storage/kernel should be triggering that nohide mount
for /export/storage/kernel) so I figured maybe that automatic nohide
stuff was broken.  I'll try by hand:

[root@dhcp231-145 ~]# mount paris:/export/storage/kernel /storage/kernel
mount.nfs: Stale NFS file handle

Same thing.  Nothing in dmesg or /var/log/messages.  I know this worked
not long ago....

-Eric

Re: 2.6.24-rc3 unable to mount something which should use nohide

[Trond Myklebust]

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On Thu, 2007-11-29 at 11:44 -0500, Eric Paris wrote:
> NFS server "paris" (some 2.6.18 based kernel):
> 
> [root@paris ~]# mount | grep storage
> /dev/mapper/StorageVG01-LogVol00 on /export/storage type ext3 (rw)
> /dev/mapper/KernelVG01-LogVol00 on /export/storage/kernel type ext3 (rw)
> [root@paris ~]# cat /etc/exports
> /export/storage         *(rw,sync,all_squash,anonuid=500,anongid=500)
> /export/storage/kernel  *(rw,sync,all_squash,anonuid=500,anongid=500,nohide)
> 
> On my clients x86_64 running an almost clean-from-git 2.6.24-rc3 kernel:
> 
> [root@dhcp231-145 ~]# mount -o noatime paris:/export/storage /storage
> [root@dhcp231-145 ~]# ls /storage/kernel
> ls: cannot access /storage/kernel: Stale NFS file handle
> 
> (notice /storage/kernel should be triggering that nohide mount
> for /export/storage/kernel) so I figured maybe that automatic nohide
> stuff was broken.  I'll try by hand:
> 
> [root@dhcp231-145 ~]# mount paris:/export/storage/kernel /storage/kernel
> mount.nfs: Stale NFS file handle
> 
> Same thing.  Nothing in dmesg or /var/log/messages.  I know this worked
> not long ago....

Yep. I think the following patch ought to fix it.

Cheers
  Trond



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commit 72e40add4adad50613083f1fda117fd74aa875ac
Author: Trond Myklebust <Trond.Myklebust@netapp.com>
Date:   Thu Nov 29 12:39:46 2007 -0500

    NFS: Fix NFS mountpoint crossing...
    
    The check that was added to nfs_xdev_get_sb() to work around broken
    servers, works fine for NFSv2, but causes mountpoint crossing on NFSv3 to
    always return ESTALE.
    
    Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 2426e71..ea92920 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -1475,7 +1475,7 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
 		error = PTR_ERR(mntroot);
 		goto error_splat_super;
 	}
-	if (mntroot->d_inode->i_op != &nfs_dir_inode_operations) {
+	if (mntroot->d_inode->i_op != server->nfs_client->rpc_ops->dir_inode_ops) {
 		dput(mntroot);
 		error = -ESTALE;
 		goto error_splat_super;

Re: 2.6.24-rc3 unable to mount something which should use nohide

[Eric Paris]

On Thu, 2007-11-29 at 12:41 -0500, Trond Myklebust wrote:
> On Thu, 2007-11-29 at 11:44 -0500, Eric Paris wrote:
> > 
> > [root@dhcp231-145 ~]# mount paris:/export/storage/kernel /storage/kernel
> > mount.nfs: Stale NFS file handle
> > 
> > Same thing.  Nothing in dmesg or /var/log/messages.  I know this worked
> > not long ago....
> 
> Yep. I think the following patch ought to fix it.
> 
> Cheers
>   Trond

Worked like a charm, thanks!

-Eric