1 files changed, 14 insertions, 9 deletions

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 3c4b2f1b64d0..94cf97b901d7 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -933,15 +933,20 @@ struct dentry_operations {
         dynamic_dname() helper function is provided to take care of this.
 
   d_automount: called when an automount dentry is to be traversed (optional).
-        This should create a new VFS mount record, mount it on the directory
-        and return the record to the caller.  The caller is supplied with a
-        path parameter giving the automount directory to describe the automount
-        target and the parent VFS mount record to provide inheritable mount
-        parameters.  NULL should be returned if someone else managed to make
-        the automount first.  If the automount failed, then an error code
-        should be returned.  If -EISDIR is returned, then the directory will
-        be treated as an ordinary directory and returned to pathwalk to
-        continue walking.
+        This should create a new VFS mount record and return the record to the
+        caller.  The caller is supplied with a path parameter giving the
+        automount directory to describe the automount target and the parent
+        VFS mount record to provide inheritable mount parameters.  NULL should
+        be returned if someone else managed to make the automount first.  If
+        the vfsmount creation failed, then an error code should be returned.
+        If -EISDIR is returned, then the directory will be treated as an
+        ordinary directory and returned to pathwalk to continue walking.
+
+        If a vfsmount is returned, the caller will attempt to mount it on the
+        mountpoint and will remove the vfsmount from its expiration list in
+        the case of failure.  The vfsmount should be returned with 2 refs on
+        it to prevent automatic expiration - the caller will clean up the
+        additional ref.
 
         This function is only used if DCACHE_NEED_AUTOMOUNT is set on the
         dentry.  This is set by __d_instantiate() if S_AUTOMOUNT is set on the