Re: [RFC] breakage in bsg

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sun, Jul 20, 2008 at 05:34:06PM +0100, Al Viro wrote:

> 	* cmd_filter thing is broken as well (we have no access to
> gendisk in question and there's a lot of obvious issues when you have
> several openers).
> 
> #2 and part of #3 are fixable, but I really don't see what to do with #1.
> If nothing else, it's absolutely incompatible with cmd_filter, even if you
> leave aside the issue with non-IDE/non-SCSI drivers.

Actually, cmd_filter changeset breaks all users of blk_verify_command().
It expects that struct file passed to will be that of a block device:
        inode = file->f_dentry->d_inode;
        if (!inode)
                return -EINVAL;

        disk = inode->i_bdev->bd_disk;

        return blk_cmd_filter_verify_command(&disk->cmd_filter,
                                                 cmd, &file->f_mode);

Unfortunately, all of those can get struct file of *character* device, with
obvious results.

The minimal fix is to pass disk / mode explicitly.  I'll post the patch,
but that still leaves bsg broken.