Commit c2df1968 authored by Al Viro's avatar Al Viro
Browse files

lift all calls of step_into() out of follow_dotdot/follow_dotdot_rcu 



lift step_into() into handle_dots() (where they merge with each other);
have follow_... return dentry and pass inode/seq to the caller.

[braino fix folded; kudos to Qian Cai <cai@lca.pw> for reporting it]

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6dfd9fe5

fs/namei.c

+37 −34
Original line number Diff line number Diff line
@@ -1687,31 +1687,29 @@ static const char *step_into(struct nameidata *nd, int flags, 
	return pick_link(nd, &path, inode, seq, flags);

}



static const char *follow_dotdot_rcu(struct nameidata *nd)

static struct dentry *follow_dotdot_rcu(struct nameidata *nd,

					struct inode **inodep,

					unsigned *seqp)

{

	struct dentry *parent = NULL;

	struct inode *inode = nd->inode;

	unsigned seq;



	while (1) {

		if (path_equal(&nd->path, &nd->root))

			break;

		if (nd->path.dentry != nd->path.mnt->mnt_root) {

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

			struct dentry *parent = old->d_parent;



			parent = old->d_parent;

			inode = parent->d_inode;

			seq = read_seqcount_begin(&parent->d_seq);

			*inodep = parent->d_inode;

			*seqp = read_seqcount_begin(&parent->d_seq);

			if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq)))

				return ERR_PTR(-ECHILD);

			if (unlikely(!path_connected(nd->path.mnt, parent)))

				return ERR_PTR(-ECHILD);

			break;

			return parent;

		} else {

			struct mount *mnt = real_mount(nd->path.mnt);

			struct mount *mparent = mnt->mnt_parent;

			struct dentry *mountpoint = mnt->mnt_mountpoint;

			struct inode *inode2 = mountpoint->d_inode;

			struct inode *inode = mountpoint->d_inode;

			unsigned seq = read_seqcount_begin(&mountpoint->d_seq);

			if (unlikely(read_seqretry(&mount_lock, nd->m_seq)))

				return ERR_PTR(-ECHILD);
@@ -1722,54 +1720,51 @@ static const char *follow_dotdot_rcu(struct nameidata *nd) 
			/* we know that mountpoint was pinned */

			nd->path.dentry = mountpoint;

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

			inode = nd->inode = inode2;

			nd->inode = inode;

			nd->seq = seq;

		}

	}

	if (unlikely(!parent)) {

	if (unlikely(nd->flags & LOOKUP_BENEATH))

		return ERR_PTR(-ECHILD);

		return step_into(nd, WALK_NOFOLLOW,

				 nd->path.dentry, nd->inode, nd->seq);

	} else {

		return step_into(nd, WALK_NOFOLLOW, parent, inode, seq);

	}

	return NULL;

}



static const char *follow_dotdot(struct nameidata *nd)

static struct dentry *follow_dotdot(struct nameidata *nd,

				 struct inode **inodep,

				 unsigned *seqp)

{

	struct dentry *parent = NULL;

	while (1) {

		if (path_equal(&nd->path, &nd->root))

			break;

		if (nd->path.dentry != nd->path.mnt->mnt_root) {

			/* rare case of legitimate dget_parent()... */

			parent = dget_parent(nd->path.dentry);

			struct dentry *parent = dget_parent(nd->path.dentry);

			if (unlikely(!path_connected(nd->path.mnt, parent))) {

				dput(parent);

				return ERR_PTR(-ENOENT);

			}

			break;

			*seqp = 0;

			*inodep = parent->d_inode;

			return parent;

		}

		if (!follow_up(&nd->path))

			break;

		if (unlikely(nd->flags & LOOKUP_NO_XDEV))

			return ERR_PTR(-EXDEV);

	}

	if (unlikely(!parent)) {

	if (unlikely(nd->flags & LOOKUP_BENEATH))

		return ERR_PTR(-EXDEV);

		return step_into(nd, WALK_NOFOLLOW,

				 dget(nd->path.dentry), nd->inode, nd->seq);

	} else {

		return step_into(nd, WALK_NOFOLLOW, parent, parent->d_inode, 0);

	}

	dget(nd->path.dentry);

	return NULL;

}



static const char *handle_dots(struct nameidata *nd, int type)

{

	if (type == LAST_DOTDOT) {

		const char *error = NULL;

		struct dentry *parent;

		struct inode *inode;

		unsigned seq;



		if (!nd->root.mnt) {

			error = ERR_PTR(set_root(nd));
@@ -1777,10 +1772,18 @@ static const char *handle_dots(struct nameidata *nd, int type) 
				return error;

		}

		if (nd->flags & LOOKUP_RCU)

			error = follow_dotdot_rcu(nd);

			parent = follow_dotdot_rcu(nd, &inode, &seq);

		else

			error = follow_dotdot(nd);

		if (error)

			parent = follow_dotdot(nd, &inode, &seq);

		if (IS_ERR(parent))

			return ERR_CAST(parent);

		if (unlikely(!parent))

			error = step_into(nd, WALK_NOFOLLOW,

					 nd->path.dentry, nd->inode, nd->seq);

		else

			error = step_into(nd, WALK_NOFOLLOW,

					 parent, inode, seq);

		if (unlikely(error))

			return error;



		if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) {