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, 7 insertions, 2 deletions

diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index 4b6825740dd5..cfe55731b6dc 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -320,9 +320,14 @@ static int export_encode_fh(struct dentry *dentry, struct fid *fid,
         struct inode * inode = dentry->d_inode;
         int len = *max_len;
         int type = FILEID_INO32_GEN;
-        
-        if (len < 2 || (connectable && len < 4))
+
+        if (connectable && (len < 4)) {
+                *max_len = 4;
+                return 255;
+        } else if (len < 2) {
+                *max_len = 2;
                 return 255;
+        }
 
         len = 2;
         fid->i32.ino = inode->i_ino;