NFS: Don't silently fail setattr() requests on mountpoints

commit ab225417825963b6dc66be7ea80f94ac1378dfdf upstream.

Ensure that any setattr and getattr requests for junctions and/or
mountpoints are sent to the server. Ever since commit
0ec26fd0698 (vfs: automount should ignore LOOKUP_FOLLOW), we have
silently dropped any setattr requests to a server-side mountpoint.
For referrals, we have silently dropped both getattr and setattr
requests.

This patch restores the original behaviour for setattr on mountpoints,
and tries to do the same for referrals, provided that we have a
filehandle...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index a86873e721390b2b7f2eb8c02c5df72226d1624a..31df53ee170380942037c9f7a20dde5ef4a392f8 100644 (file)
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -289,11 +289,31 @@ out_nofree:
        return mnt;
 }
 
+static int
+nfs_namespace_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+       if (NFS_FH(dentry->d_inode)->size != 0)
+               return nfs_getattr(mnt, dentry, stat);
+       generic_fillattr(dentry->d_inode, stat);
+       return 0;
+}
+
+static int
+nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
+{
+       if (NFS_FH(dentry->d_inode)->size != 0)
+               return nfs_setattr(dentry, attr);
+       return -EACCES;
+}
+
 const struct inode_operations nfs_mountpoint_inode_operations = {
        .getattr        = nfs_getattr,
+       .setattr        = nfs_setattr,
 };
 
 const struct inode_operations nfs_referral_inode_operations = {
+       .getattr        = nfs_namespace_getattr,
+       .setattr        = nfs_namespace_setattr,
 };
 
 static void nfs_expire_automounts(struct work_struct *work)