NFS: check for nfs_refresh_inode() errors in nfs_fhget()

If an NFS server returns a filehandle that we have previously
seen, and reports a different type, then nfs_refresh_inode()
will log a warning and return an error.

nfs_fhget() does not check for this error and may return an
inode with a different type than the one that the server
reported.

This is likely to cause confusion, and is one way that
->open_context() could return a directory inode as discussed
in the previous patch.

So if nfs_refresh_inode() returns and error, return that error
from nfs_fhget() to avoid the confusion propagating.
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

fs/nfs/inode.c

@@ -525,8 +525,14 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
 		nfs_fscache_init_inode(inode);
 
 		unlock_new_inode(inode);
-	} else
-		nfs_refresh_inode(inode, fattr);
+	} else {
+		int err = nfs_refresh_inode(inode, fattr);
+		if (err < 0) {
+			iput(inode);
+			inode = ERR_PTR(err);
+			goto out_no_inode;
+		}
+	}
 	dprintk("NFS: nfs_fhget(%s/%Lu fh_crc=0x%08x ct=%d)\n",
 		inode->i_sb->s_id,
 		(unsigned long long)NFS_FILEID(inode),