From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 23 Jun 2008 12:30:55 +0000 (-0400)
Subject: [PATCH] fix cgroup-inflicted breakage in block_dev.c
X-Git-Tag: v2.6.26-rc9~99^2~11
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe6e9c1f25ac01f848bd084ee0ee62a5a0966ff3;p=linux-2.6

[PATCH] fix cgroup-inflicted breakage in block_dev.c

devcgroup_inode_permission() expects MAY_FOO, not FMODE_FOO; kindly
keep your misdesign consistent if you positively have to inflict it
on the kernel.

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

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 470c10ceb0..10d8a0aa87 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -931,8 +931,16 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
 	struct gendisk *disk;
 	int ret;
 	int part;
+	int perm = 0;
 
-	ret = devcgroup_inode_permission(bdev->bd_inode, file->f_mode);
+	if (file->f_mode & FMODE_READ)
+		perm |= MAY_READ;
+	if (file->f_mode & FMODE_WRITE)
+		perm |= MAY_WRITE;
+	/*
+	 * hooks: /n/, see "layering violations".
+	 */
+	ret = devcgroup_inode_permission(bdev->bd_inode, perm);
 	if (ret != 0)
 		return ret;