Commit 25e195aa authored by Al Viro's avatar Al Viro
Browse files

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a rudiment of plans that got superseded before the thing went into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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 26df6034

fs/namei.c

+3 −25
Original line number Diff line number Diff line
@@ -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);

}



/*

fs/namespace.c

+8 −1
Original line number Diff line number Diff line
@@ -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

	 */