From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sat, 15 Jan 2011 18:12:53 +0000 (-0500)
Subject: do_lookup() fix
X-Git-Tag: v2.6.38-rc1~35^2~22
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=1a8edf40e7c3eee955e0dd0316a7c9d85e36f597;p=linux.git

do_lookup() fix

do_lookup() has a path leading from LOOKUP_RCU case to non-RCU
crossing of mountpoints, which breaks things badly.  If we
hit need_revalidate: and do nothing in there, we need to come
back into LOOKUP_RCU half of things, not to done: in non-RCU
one.

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

diff --git a/fs/namei.c b/fs/namei.c
index 8df7a78ace58..529e917ad2fc 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1089,6 +1089,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 		nd->seq = seq;
 		if (dentry->d_flags & DCACHE_OP_REVALIDATE)
 			goto need_revalidate;
+done2:
 		path->mnt = mnt;
 		path->dentry = dentry;
 		__follow_mount_rcu(nd, path, inode);
@@ -1143,6 +1144,8 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 		goto need_lookup;
 	if (IS_ERR(dentry))
 		goto fail;
+	if (nd->flags & LOOKUP_RCU)
+		goto done2;
 	goto done;
 
 fail: