Commit c153007b authored by Al Viro's avatar Al Viro
Browse files

teach handle_mounts() to handle RCU mode 



... and make the callers of __follow_mount_rcu() use handle_mounts().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent b023e172

fs/namei.c

+17 −29
Original line number Diff line number Diff line
@@ -1393,6 +1393,18 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, 


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

	path->dentry = dentry;

	if (nd->flags & LOOKUP_RCU) {

		unsigned int seq = *seqp;

		if (unlikely(!*inode))

			return -ENOENT;

		if (likely(__follow_mount_rcu(nd, path, inode, seqp)))

			return 1;

		if (unlazy_child(nd, dentry, seq))

			return -ECHILD;

		// *path might've been clobbered by __follow_mount_rcu()

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

		path->dentry = dentry;

	}

	ret = follow_managed(path, nd);

	if (likely(ret >= 0)) {

		*inode = d_backing_inode(path->dentry);
@@ -1620,7 +1632,6 @@ static int lookup_fast(struct nameidata *nd, 
		       struct path *path, struct inode **inode,

		       unsigned *seqp)

{

	struct vfsmount *mnt = nd->path.mnt;

	struct dentry *dentry, *parent = nd->path.dentry;

	int status = 1;
@@ -1658,21 +1669,8 @@ static int lookup_fast(struct nameidata *nd, 


		*seqp = seq;

		status = d_revalidate(dentry, nd->flags);

		if (likely(status > 0)) {

			/*

			 * Note: do negative dentry check after revalidation in

			 * case that drops it.

			 */

			if (unlikely(!*inode))

				return -ENOENT;

			path->mnt = mnt;

			path->dentry = dentry;

			if (likely(__follow_mount_rcu(nd, path, inode, seqp)))

				return 1;

			if (unlazy_child(nd, dentry, seq))

				return -ECHILD;

		if (likely(status > 0))

			return handle_mounts(nd, dentry, path, inode, seqp);

		}

		if (unlazy_child(nd, dentry, seq))

			return -ECHILD;

		if (unlikely(status == -ECHILD))
@@ -2361,21 +2359,11 @@ static int handle_lookup_down(struct nameidata *nd) 
	unsigned seq = nd->seq;

	int err;



	if (nd->flags & LOOKUP_RCU) {

		/*

		 * don't bother with unlazy_walk on failure - we are

		 * at the very beginning of walk, so we lose nothing

		 * if we simply redo everything in non-RCU mode

		 */

		path = nd->path;

		if (unlikely(!__follow_mount_rcu(nd, &path, &inode, &seq)))

			return -ECHILD;

	} else {

	if (!(nd->flags & LOOKUP_RCU))

		dget(nd->path.dentry);

	err = handle_mounts(nd, nd->path.dentry, &path, &inode, &seq);

	if (unlikely(err < 0))

		return err;

	}

	path_to_nameidata(&path, nd);

	nd->inode = inode;

	nd->seq = seq;