1 files changed, 43 insertions, 0 deletions

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index cae6d27c9f5b..94cf97b901d7 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -864,6 +864,8 @@ struct dentry_operations {
         void (*d_release)(struct dentry *);
         void (*d_iput)(struct dentry *, struct inode *);
         char *(*d_dname)(struct dentry *, char *, int);
+        struct vfsmount *(*d_automount)(struct path *);
+        int (*d_manage)(struct dentry *, bool, bool);
 };
 
   d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -930,6 +932,47 @@ struct dentry_operations {
         at the end of the buffer, and returns a pointer to the first char.
         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 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
+        inode being added.
+
+  d_manage: called to allow the filesystem to manage the transition from a
+        dentry (optional).  This allows autofs, for example, to hold up clients
+        waiting to explore behind a 'mountpoint' whilst letting the daemon go
+        past and construct the subtree there.  0 should be returned to let the
+        calling process continue.  -EISDIR can be returned to tell pathwalk to
+        use this directory as an ordinary directory and to ignore anything
+        mounted on it and not to check the automount flag.  Any other error
+        code will abort pathwalk completely.
+
+        If the 'mounting_here' parameter is true, then namespace_sem is being
+        held by the caller and the function should not initiate any mounts or
+        unmounts that it will then wait for.
+
+        If the 'rcu_walk' parameter is true, then the caller is doing a
+        pathwalk in RCU-walk mode.  Sleeping is not permitted in this mode,
+        and the caller can be asked to leave it and call again by returing
+        -ECHILD.
+
+        This function is only used if DCACHE_MANAGE_TRANSIT is set on the
+        dentry being transited from.
+
 Example :
 
 static char *pipefs_dname(struct dentry *dent, char *buffer, int buflen)