exportfs: Return the minimum required handle size

The exportfs encode handle function should return the minimum required
handle size. This helps user to find out the handle size by passing 0
handle size in the first step and then redoing to the call again with
the returned handle size value.

Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 5ee67c990602..3437b65d6d6e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2144,8 +2144,10 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
 {
         struct inode *inode = dentry->d_inode;
 
-        if (*len < 3)
+        if (*len < 3) {
+                *len = 3;
                 return 255;
+        }
 
         if (inode_unhashed(inode)) {
                 /* Unfortunately insert_inode_hash is not idempotent,