namei: make should_follow_link() store the link in nd->link (d63ff28f) · Commits · 戴 / test

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 @@ done:
		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 @@ retry_lookup:
		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)) {

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