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Commit ba8f4613 authored by Al Viro's avatar Al Viro
Browse files

namei: saner calling conventions for mountpoint_last() 



leave the result in nd->path, have caller do follow_mount() and
copy it to the final destination.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c1d4dd27

fs/namei.c

+25 −25
Original line number Diff line number Diff line
@@ -2561,7 +2561,6 @@ EXPORT_SYMBOL(user_path_at_empty); 
/**

 * mountpoint_last - look up last component for umount

 * @nd:   pathwalk nameidata - currently pointing at parent directory of "last"

 * @path: pointer to container for result

 *

 * This is a special lookup_last function just for umount. In this case, we

 * need to resolve the path without doing any revalidation.
@@ -2574,23 +2573,20 @@ EXPORT_SYMBOL(user_path_at_empty); 
 *

 * Returns:

 * -error: if there was an error during lookup. This includes -ENOENT if the

 *         lookup found a negative dentry. The nd->path reference will also be

 *         put in this case.

 *         lookup found a negative dentry.

 *

 * 0:      if we successfully resolved nd->path and found it to not to be a

 *         symlink that needs to be followed. "path" will also be populated.

 *         The nd->path reference will also be put.

 * 0:      if we successfully resolved nd->last and found it to not to be a

 *         symlink that needs to be followed.

 *

 * 1:      if we successfully resolved nd->last and found it to be a symlink

 *         that needs to be followed. "path" will be populated with the path

 *         to the link, and nd->path will *not* be put.

 *         that needs to be followed.

 */

static int

mountpoint_last(struct nameidata *nd, struct path *path)

mountpoint_last(struct nameidata *nd)

{

	int error = 0;

	struct dentry *dentry;

	struct dentry *dir = nd->path.dentry;

	struct path path;



	/* If we're in rcuwalk, drop out of it to handle last component */

	if (nd->flags & LOOKUP_RCU) {
@@ -2604,36 +2600,34 @@ mountpoint_last(struct nameidata *nd, struct path *path) 
		error = handle_dots(nd, nd->last_type);

		if (error)

			return error;

		dentry = dget(nd->path.dentry);

		path.dentry = dget(nd->path.dentry);

	} else {

		dentry = d_lookup(dir, &nd->last);

		if (!dentry) {

		path.dentry = d_lookup(dir, &nd->last);

		if (!path.dentry) {

			/*

			 * No cached dentry. Mounted dentries are pinned in the

			 * cache, so that means that this dentry is probably

			 * a symlink or the path doesn't actually point

			 * to a mounted dentry.

			 */

			dentry = lookup_slow(&nd->last, dir,

			path.dentry = lookup_slow(&nd->last, dir,

					     nd->flags | LOOKUP_NO_REVAL);

			if (IS_ERR(dentry))

				return PTR_ERR(dentry);

			if (IS_ERR(path.dentry))

				return PTR_ERR(path.dentry);

		}

	}

	if (d_is_negative(dentry)) {

		dput(dentry);

	if (d_is_negative(path.dentry)) {

		dput(path.dentry);

		return -ENOENT;

	}

	if (nd->depth)

		put_link(nd);

	path->dentry = dentry;

	path->mnt = nd->path.mnt;

	error = should_follow_link(nd, path, nd->flags & LOOKUP_FOLLOW,

				   d_backing_inode(dentry), 0);

	path.mnt = nd->path.mnt;

	error = should_follow_link(nd, &path, nd->flags & LOOKUP_FOLLOW,

				   d_backing_inode(path.dentry), 0);

	if (unlikely(error))

		return error;

	mntget(path->mnt);

	follow_mount(path);

	path_to_nameidata(&path, nd);

	return 0;

}
@@ -2654,13 +2648,19 @@ path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path) 
	if (IS_ERR(s))

		return PTR_ERR(s);

	while (!(err = link_path_walk(s, nd)) &&

		(err = mountpoint_last(nd, path)) > 0) {

		(err = mountpoint_last(nd)) > 0) {

		s = trailing_symlink(nd);

		if (IS_ERR(s)) {

			err = PTR_ERR(s);

			break;

		}

	}

	if (!err) {

		*path = nd->path;

		nd->path.mnt = NULL;

		nd->path.dentry = NULL;

		follow_mount(path);

	}

	terminate_walk(nd);

	return err;

}