From b7300b78d1a87625975a799a109a2f98d77757c8 Mon Sep 17 00:00:00 2001 From: Chris Wright Date: Tue, 10 Aug 2010 18:02:55 -0700 Subject: [PATCH] blkdev: cgroup whitelist permission fix The cgroup device whitelist code gets confused when trying to grant permission to a disk partition that is not currently open. Part of blkdev_open() includes __blkdev_get() on the whole disk. Basically, the only ways to reliably allow a cgroup access to a partition on a block device when using the whitelist are to 1) also give it access to the whole block device or 2) make sure the partition is already open in a different context. The patch avoids the cgroup check for the whole disk case when opening a partition. Addresses https://bugzilla.redhat.com/show_bug.cgi?id=589662 Signed-off-by: Chris Wright Acked-by: Serge E. Hallyn Tested-by: Serge E. Hallyn Reported-by: Vivek Goyal Cc: Al Viro Cc: Christoph Hellwig Cc: "Daniel P. Berrange" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/block_dev.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 66411463b734..50e8c8582faa 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1340,10 +1340,12 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) /* * hooks: /n/, see "layering violations". */ - ret = devcgroup_inode_permission(bdev->bd_inode, perm); - if (ret != 0) { - bdput(bdev); - return ret; + if (!for_part) { + ret = devcgroup_inode_permission(bdev->bd_inode, perm); + if (ret != 0) { + bdput(bdev); + return ret; + } } restart: