From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 12 May 2015 04:10:18 +0000 (-0400)
Subject: namei: unlazy_walk() doesn't need to mess with current->fs anymore
X-Git-Tag: v4.2-rc1~180^2~20
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=5a8d87e8ed1d6aabdb865fea31e337b2c627dbe0;p=linux.git

namei: unlazy_walk() doesn't need to mess with current->fs anymore

now that we have ->root_seq, legitimize_path(&nd->root, nd->root_seq)
will do just fine...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/namei.c b/fs/namei.c
index a5ed0d070a20..0cccb24ac0b7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -651,7 +651,6 @@ static bool legitimize_links(struct nameidata *nd)
  */
 static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq)
 {
-	struct fs_struct *fs = current->fs;
 	struct dentry *parent = nd->path.dentry;
 
 	BUG_ON(!(nd->flags & LOOKUP_RCU));
@@ -691,13 +690,11 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq
 	 * still valid and get it if required.
 	 */
 	if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
-		spin_lock(&fs->lock);
-		if (unlikely(!path_equal(&nd->root, &fs->root))) {
-			spin_unlock(&fs->lock);
-			goto drop_dentry;
+		if (unlikely(!legitimize_path(nd, &nd->root, nd->root_seq))) {
+			rcu_read_unlock();
+			dput(dentry);
+			return -ECHILD;
 		}
-		path_get(&nd->root);
-		spin_unlock(&fs->lock);
 	}
 
 	rcu_read_unlock();