[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>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 470c10ceb0fb..10d8a0aa871a 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;