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, 6 insertions, 2 deletions

diff --git a/fs/isofs/export.c b/fs/isofs/export.c
index ed752cb38474..dd4687ff30d0 100644
--- a/fs/isofs/export.c
+++ b/fs/isofs/export.c
@@ -124,9 +124,13 @@ isofs_export_encode_fh(struct dentry *dentry,
          * offset of the inode and the upper 16 bits of fh32[1] to
          * hold the offset of the parent.
          */
-
-        if (len < 3 || (connectable && len < 5))
+        if (connectable && (len < 5)) {
+                *max_len = 5;
+                return 255;
+        } else if (len < 3) {
+                *max_len = 3;
                 return 255;
+        }
 
         len = 3;
         fh32[0] = ei->i_iget5_block;