follow_automount(): get rid of dead^Wstillborn code

1) no instances of ->d_automount() have ever made use of the "return
ERR_PTR(-EISDIR) if you don't feel like mounting anything" - that's
a rudiment of plans that got superseded before the thing went into
the tree.  Despite the comment in follow_automount(), autofs has
never done that.

2) if there's no ->d_automount() in dentry_operations, filesystems
should not set DCACHE_NEED_AUTOMOUNT in the first place.  None have
ever done so...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/namei.c b/fs/namei.c
index 626eddb..39dd56f 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1210,10 +1210,7 @@ EXPORT_SYMBOL(follow_up);
  */
 static int follow_automount(struct path *path, struct nameidata *nd)
 {
-       struct vfsmount *mnt;
-
-       if (!path->dentry->d_op || !path->dentry->d_op->d_automount)
-               return -EREMOTE;
+       struct dentry *dentry = path->dentry;
 
        /* We don't want to mount if someone's just doing a stat -
         * unless they're stat'ing a directory and appended a '/' to
@@ -1228,33 +1225,14 @@ static int follow_automount(struct path *path, struct nameidata *nd)
         */
        if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY |
                           LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) &&
-           path->dentry->d_inode)
+           dentry->d_inode)
                return -EISDIR;
 
        nd->total_link_count++;
        if (nd->total_link_count >= 40)
                return -ELOOP;
 
-       mnt = path->dentry->d_op->d_automount(path);
-       if (IS_ERR(mnt)) {
-               /*
-                * The filesystem is allowed to return -EISDIR here to indicate
-                * it doesn't want to automount.  For instance, autofs would do
-                * this so that its userspace daemon can mount on this dentry.
-                *
-                * However, we can only permit this if it's a terminal point in
-                * the path being looked up; if it wasn't then the remainder of
-                * the path is inaccessible and we should say so.
-                */
-               if (PTR_ERR(mnt) == -EISDIR && (nd->flags & LOOKUP_PARENT))
-                       return -EREMOTE;
-               return PTR_ERR(mnt);
-       }
-
-       if (!mnt)
-               return 0;
-
-       return finish_automount(mnt, path);
+       return finish_automount(dentry->d_op->d_automount(path), path);
 }
 
 /*

diff --git a/fs/namespace.c b/fs/namespace.c
index 777c311..7439803 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2824,9 +2824,16 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
 int finish_automount(struct vfsmount *m, struct path *path)
 {
        struct dentry *dentry = path->dentry;
-       struct mount *mnt = real_mount(m);
        struct mountpoint *mp;
+       struct mount *mnt;
        int err;
+
+       if (!m)
+               return 0;
+       if (IS_ERR(m))
+               return PTR_ERR(m);
+
+       mnt = real_mount(m);
        /* The new mount record should have at least 2 refs to prevent it being
         * expired before we get a chance to add it
         */