Commit abc2c632 authored by Al Viro's avatar Al Viro
Browse files

follow_dotdot{,_rcu}(): lift switching nd->path to parent out of loop 



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent a6a7eb76

fs/namei.c

+12 −8
Original line number Diff line number Diff line
@@ -1365,7 +1365,9 @@ static inline int handle_mounts(struct nameidata *nd, struct dentry *dentry, 


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)) {
@@ -1375,15 +1377,12 @@ static int follow_dotdot_rcu(struct nameidata *nd) 
		}

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

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

			struct dentry *parent = old->d_parent;

			unsigned seq;



			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;

			nd->path.dentry = parent;

			nd->seq = seq;

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

				return -ECHILD;

			break;
@@ -1406,6 +1405,10 @@ static int follow_dotdot_rcu(struct nameidata *nd) 
			nd->seq = seq;

		}

	}

	if (likely(parent)) {

		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);
@@ -1442,7 +1445,7 @@ static void follow_mount(struct path *path) 


static int follow_dotdot(struct nameidata *nd)

{

	struct dentry *parent;

	struct dentry *parent = NULL;

	while (1) {

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

			if (unlikely(nd->flags & LOOKUP_BENEATH))
@@ -1452,13 +1455,10 @@ static int follow_dotdot(struct nameidata *nd) 
		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;

			}

			dput(nd->path.dentry);

			nd->path.dentry = parent;

			break;

		}

		if (!follow_up(&nd->path))
@@ -1466,6 +1466,10 @@ static int follow_dotdot(struct nameidata *nd) 
		if (unlikely(nd->flags & LOOKUP_NO_XDEV))

			return -EXDEV;

	}

	if (likely(parent)) {

		dput(nd->path.dentry);

		nd->path.dentry = parent;

	}

	follow_mount(&nd->path);

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

	return 0;