1 files changed, 15 insertions, 1 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 7d822fae7765..10d8a0aa871a 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -12,6 +12,7 @@
 #include <linux/kmod.h>
 #include <linux/major.h>
 #include <linux/smp_lock.h>
+#include <linux/device_cgroup.h>
 #include <linux/highmem.h>
 #include <linux/blkdev.h>
 #include <linux/module.h>
@@ -928,9 +929,22 @@ static int do_open(struct block_device *bdev, struct file *file, int for_part)
 {
         struct module *owner = NULL;
         struct gendisk *disk;
-        int ret = -ENXIO;
+        int ret;
         int part;
+        int perm = 0;
+
+        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;
 
+        ret = -ENXIO;
         file->f_mapping = bdev->bd_inode->i_mapping;
         lock_kernel();
         disk = get_gendisk(bdev->bd_dev, &part);