[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 470c10ceb0fb3a33dc8f28e7e8b2d3535042075b..10d8a0aa871a096eb3d8577b01d285aa9c1fa433 100644 (file)
--- 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;