Commit 957dd41d authored by Al Viro's avatar Al Viro
Browse files

move handle_dots(), follow_dotdot() and follow_dotdot_rcu() past step_into() 



pure move; we are going to have step_into() called by that bunch.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c9a0f75d

fs/namei.c

+130 −130
Original line number Diff line number Diff line
@@ -1363,70 +1363,6 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, 
	return ret;

}



static int follow_dotdot_rcu(struct nameidata *nd)

{

	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;



			parent = old->d_parent;

			inode = parent->d_inode;

			seq = read_seqcount_begin(&parent->d_seq);

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

				return -ECHILD;

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

				return -ECHILD;

			break;

		} 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;

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

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

				return -ECHILD;

			if (&mparent->mnt == nd->path.mnt)

				break;

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

				return -ECHILD;

			/* we know that mountpoint was pinned */

			nd->path.dentry = mountpoint;

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

			inode = inode2;

			nd->seq = seq;

		}

	}

	if (unlikely(!parent)) {

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

			return -ECHILD;

	} else {

		nd->path.dentry = parent;

		nd->seq = seq;

	}

	while (unlikely(d_mountpoint(nd->path.dentry))) {

		struct mount *mounted;

		mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);

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

			return -ECHILD;

		if (!mounted)

			break;

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

			return -ECHILD;

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

		nd->path.dentry = mounted->mnt.mnt_root;

		inode = nd->path.dentry->d_inode;

		nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);

	}

	nd->inode = inode;

	return 0;

}



/*

 * Skip to top of mountpoint pile in refwalk mode for follow_dotdot()

 */
@@ -1443,38 +1379,6 @@ static void follow_mount(struct path *path) 
	}

}



static int follow_dotdot(struct nameidata *nd)

{

	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);

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

				dput(parent);

				return -ENOENT;

			}

			break;

		}

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

			break;

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

			return -EXDEV;

	}

	if (unlikely(!parent)) {

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

			return -EXDEV;

	} else {

		dput(nd->path.dentry);

		nd->path.dentry = parent;

	}

	follow_mount(&nd->path);

	nd->inode = nd->path.dentry->d_inode;

	return 0;

}



/*

 * This looks up the name in dcache and possibly revalidates the found dentry.

 * NULL is returned if the dentry does not exist in the cache.
@@ -1654,40 +1558,6 @@ static inline int may_lookup(struct nameidata *nd) 
	return inode_permission(nd->inode, MAY_EXEC);

}



static inline int handle_dots(struct nameidata *nd, int type)

{

	if (type == LAST_DOTDOT) {

		int error = 0;



		if (!nd->root.mnt) {

			error = set_root(nd);

			if (error)

				return error;

		}

		if (nd->flags & LOOKUP_RCU)

			error = follow_dotdot_rcu(nd);

		else

			error = follow_dotdot(nd);

		if (error)

			return error;



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

			/*

			 * If there was a racing rename or mount along our

			 * path, then we can't be sure that ".." hasn't jumped

			 * above nd->root (and so userspace should retry or use

			 * some fallback).

			 */

			smp_rmb();

			if (unlikely(__read_seqcount_retry(&mount_lock.seqcount, nd->m_seq)))

				return -EAGAIN;

			if (unlikely(__read_seqcount_retry(&rename_lock.seqcount, nd->r_seq)))

				return -EAGAIN;

		}

	}

	return 0;

}



enum {WALK_TRAILING = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};



static const char *pick_link(struct nameidata *nd, struct path *link,
@@ -1817,6 +1687,136 @@ static const char *step_into(struct nameidata *nd, int flags, 
	return pick_link(nd, &path, inode, seq, flags);

}



static int follow_dotdot_rcu(struct nameidata *nd)

{

	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;



			parent = old->d_parent;

			inode = parent->d_inode;

			seq = read_seqcount_begin(&parent->d_seq);

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

				return -ECHILD;

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

				return -ECHILD;

			break;

		} 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;

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

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

				return -ECHILD;

			if (&mparent->mnt == nd->path.mnt)

				break;

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

				return -ECHILD;

			/* we know that mountpoint was pinned */

			nd->path.dentry = mountpoint;

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

			inode = inode2;

			nd->seq = seq;

		}

	}

	if (unlikely(!parent)) {

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

			return -ECHILD;

	} else {

		nd->path.dentry = parent;

		nd->seq = seq;

	}

	while (unlikely(d_mountpoint(nd->path.dentry))) {

		struct mount *mounted;

		mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry);

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

			return -ECHILD;

		if (!mounted)

			break;

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

			return -ECHILD;

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

		nd->path.dentry = mounted->mnt.mnt_root;

		inode = nd->path.dentry->d_inode;

		nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);

	}

	nd->inode = inode;

	return 0;

}



static int follow_dotdot(struct nameidata *nd)

{

	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);

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

				dput(parent);

				return -ENOENT;

			}

			break;

		}

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

			break;

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

			return -EXDEV;

	}

	if (unlikely(!parent)) {

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

			return -EXDEV;

	} else {

		dput(nd->path.dentry);

		nd->path.dentry = parent;

	}

	follow_mount(&nd->path);

	nd->inode = nd->path.dentry->d_inode;

	return 0;

}



static inline int handle_dots(struct nameidata *nd, int type)

{

	if (type == LAST_DOTDOT) {

		int error = 0;



		if (!nd->root.mnt) {

			error = set_root(nd);

			if (error)

				return error;

		}

		if (nd->flags & LOOKUP_RCU)

			error = follow_dotdot_rcu(nd);

		else

			error = follow_dotdot(nd);

		if (error)

			return error;



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

			/*

			 * If there was a racing rename or mount along our

			 * path, then we can't be sure that ".." hasn't jumped

			 * above nd->root (and so userspace should retry or use

			 * some fallback).

			 */

			smp_rmb();

			if (unlikely(__read_seqcount_retry(&mount_lock.seqcount, nd->m_seq)))

				return -EAGAIN;

			if (unlikely(__read_seqcount_retry(&rename_lock.seqcount, nd->r_seq)))

				return -EAGAIN;

		}

	}

	return 0;

}



static const char *walk_component(struct nameidata *nd, int flags)

{

	struct dentry *dentry;