Commit d63ff28f authored by Al Viro's avatar Al Viro
Browse files

namei: make should_follow_link() store the link in nd->link 



... if it decides to follow, that is.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 4693a547

fs/namei.c

+33 −29
Original line number Diff line number Diff line
@@ -1566,15 +1566,31 @@ static void terminate_walk(struct nameidata *nd) 
		put_link(nd);

}



static int pick_link(struct nameidata *nd, struct path *link)

{

	if (nd->flags & LOOKUP_RCU) {

		if (unlikely(nd->path.mnt != link->mnt ||

			     unlazy_walk(nd, link->dentry))) {

			return -ECHILD;

		}

	}

	nd->link = *link;

	return 1;

}



/*

 * Do we need to follow links? We _really_ want to be able

 * to do this check without having to look at inode->i_op,

 * so we keep a cache of "no, this doesn't need follow_link"

 * for the common case.

 */

static inline int should_follow_link(struct dentry *dentry, int follow)

static inline int should_follow_link(struct nameidata *nd, struct path *link, int follow)

{

	return unlikely(d_is_symlink(dentry)) ? follow : 0;

	if (likely(!d_is_symlink(link->dentry)))

		return 0;

	if (!follow)

		return 0;

	return pick_link(nd, link);

}



enum {WALK_GET = 1, WALK_PUT = 2};
@@ -1612,17 +1628,9 @@ static int walk_component(struct nameidata *nd, int flags) 


	if (flags & WALK_PUT)

		put_link(nd);

	if (should_follow_link(path.dentry, flags & WALK_GET)) {

		if (nd->flags & LOOKUP_RCU) {

			if (unlikely(nd->path.mnt != path.mnt ||

				     unlazy_walk(nd, path.dentry))) {

				return -ECHILD;

			}

		}

		BUG_ON(inode != path.dentry->d_inode);

		nd->link = path;

		return 1;

	}

	err = should_follow_link(nd, &path, flags & WALK_GET);

	if (unlikely(err))

		return err;

	path_to_nameidata(&path, nd);

	nd->inode = inode;

	return 0;
@@ -2375,9 +2383,11 @@ mountpoint_last(struct nameidata *nd, struct path *path) 
		put_link(nd);

	path->dentry = dentry;

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

	if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW)) {

		nd->link = *path;

		return 1;

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

	if (unlikely(error)) {

		if (error < 0)

			goto out;

		return error;

	}

	mntget(path->mnt);

	follow_mount(path);
@@ -3095,19 +3105,13 @@ static int do_last(struct nameidata *nd, 
		goto out;

	}

finish_lookup:

	if (should_follow_link(path.dentry, nd->flags & LOOKUP_FOLLOW)) {

		if (nd->flags & LOOKUP_RCU) {

			if (unlikely(nd->path.mnt != path.mnt ||

				     unlazy_walk(nd, path.dentry))) {

				error = -ECHILD;

				goto out;

			}

		}

		BUG_ON(inode != path.dentry->d_inode);

	if (nd->depth)

		put_link(nd);

		nd->link = path;

		return 1;

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

	if (unlikely(error)) {

		if (error < 0)

			goto out;

		return error;

	}



	if (unlikely(d_is_symlink(path.dentry)) && !(open_flag & O_PATH)) {