linux-kernel - [PATCH 01/21] namei: unlazy_walk() doesn't need to mess with current->fs anymore

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Date:	Wed, 13 May 2015 23:25:55 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Neil Brown <neilb@...e.de>, Christoph Hellwig <hch@...radead.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 01/21] namei: unlazy_walk() doesn't need to mess with current->fs anymore

From: Al Viro <viro@...iv.linux.org.uk>

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

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 3ee1d65..e736722 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();
-- 
2.1.4

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