linux-kernel - [PATCH 25/41] union-mount: stop lookup when directory has S

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Date:	Wed, 21 Oct 2009 12:19:23 -0700
From:	Valerie Aurora <vaurora@...hat.com>
To:	Jan Blunck <jblunck@...e.de>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	Christoph Hellwig <hch@...radead.org>,
	Andy Whitcroft <apw@...onical.com>,
	Scott James Remnant <scott@...onical.com>,
	Sandu Popa Marius <sandupopamarius@...il.com>,
	Jan Rekorajski <baggins@...h.mimuw.edu.pl>,
	"J. R. Okajima" <hooanon05@...oo.co.jp>,
	Arnd Bergmann <arnd@...db.de>,
	Vladimir Dronnikov <dronnikov@...il.com>,
	Felix Fietkau <nbd@...nwrt.org>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jan Blunck <jblunck@...e.de>
Subject: [PATCH 25/41] union-mount: stop lookup when directory has S_OPAQUE flag set

From: Jan Blunck <jblunck@...e.de>

Honor the S_OPAQUE flag in the union path lookup.

Signed-off-by: Jan Blunck <jblunck@...e.de>
Signed-off-by: Valerie Aurora <vaurora@...hat.com>
---
 fs/namei.c |   17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index b279686..8ebbf4f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -523,6 +523,9 @@ static int __cache_lookup_build_union(struct nameidata *nd, struct qstr *name,
 			path_put(&last);
 		last.dentry = dentry;
 		last.mnt = mntget(nd->path.mnt);
+
+		if (IS_OPAQUE(last.dentry->d_inode))
+			break;
 	}
 
 	if (last.dentry != path->dentry)
@@ -562,7 +565,8 @@ static int cache_lookup_union(struct nameidata *nd, struct qstr *name,
 
 		/* only directories can be part of a union stack */
 		if (!path->dentry->d_inode ||
-		    !S_ISDIR(path->dentry->d_inode->i_mode))
+		    !S_ISDIR(path->dentry->d_inode->i_mode) ||
+		    IS_OPAQUE(path->dentry->d_inode))
 			goto out;
 
 		/* Build the union stack for this part */
@@ -804,6 +808,9 @@ static int __real_lookup_build_union(struct nameidata *nd, struct qstr *name,
 			path_put(&last);
 		last.dentry = next.dentry;
 		last.mnt = mntget(next.mnt);
+
+		if (IS_OPAQUE(last.dentry->d_inode))
+			break;
 	}
 
 	if (last.dentry != path->dentry)
@@ -825,7 +832,8 @@ static int real_lookup_union(struct nameidata *nd, struct qstr *name,
 
 	/* only directories can be part of a union stack */
 	if (!path->dentry->d_inode ||
-	    !S_ISDIR(path->dentry->d_inode->i_mode))
+	    !S_ISDIR(path->dentry->d_inode->i_mode) ||
+	    IS_OPAQUE(path->dentry->d_inode))
 		goto out;
 
 	/* Build the union stack for this part */
@@ -1111,7 +1119,7 @@ static int do_lookup(struct nameidata *nd, struct qstr *name,
 {
 	int err;
 
-	if (IS_MNT_UNION(nd->path.mnt))
+	if (IS_MNT_UNION(nd->path.mnt) && !IS_OPAQUE(nd->path.dentry->d_inode))
 		goto need_union_lookup;
 
 	path->dentry = __d_lookup(nd->path.dentry, name);
@@ -1676,6 +1684,9 @@ static int __hash_lookup_build_union(struct nameidata *nd, struct qstr *name,
 			path_put(&last);
 		last.dentry = next.dentry;
 		last.mnt = mntget(next.mnt);
+
+		if (IS_OPAQUE(last.dentry->d_inode))
+			break;
 	}
 
 	if (last.dentry != path->dentry)
-- 
1.6.3.3

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