[PATCH 02/15] dm linear: support ioctls

[PATCH 02/15] dm linear: support ioctls

[Alasdair G Kergon]

From: Milan Broz <mbroz@redhat.com>

When an ioctl is performed on a device with a linear target, simply
pass it on to the underlying block device.

Note that the ioctl will pass through the filtering in blkdev_ioctl()
twice.
 
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

Index: linux-2.6.17/drivers/md/dm-linear.c
===================================================================
--- linux-2.6.17.orig/drivers/md/dm-linear.c	2006-06-21 17:45:16.000000000 +0100
+++ linux-2.6.17/drivers/md/dm-linear.c	2006-06-21 18:32:07.000000000 +0100
@@ -96,14 +96,25 @@ static int linear_status(struct dm_targe
 	return 0;
 }
 
+static int linear_ioctl(struct dm_target *ti, struct inode *inode,
+			struct file *filp, unsigned int cmd,
+			unsigned long arg)
+{
+	struct linear_c *lc = (struct linear_c *) ti->private;
+	struct block_device *bdev = lc->dev->bdev;
+
+	return blkdev_ioctl(bdev->bd_inode, filp, cmd, arg);
+}
+
 static struct target_type linear_target = {
 	.name   = "linear",
-	.version= {1, 0, 1},
+	.version= {1, 0, 2},
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
 	.dtr    = linear_dtr,
 	.map    = linear_map,
 	.status = linear_status,
+	.ioctl  = linear_ioctl,
 };
 
 int __init dm_linear_init(void)

Re: [PATCH 02/15] dm linear: support ioctls

[Andrew Morton]

On Wed, 21 Jun 2006 20:33:08 +0100
Alasdair G Kergon <agk@redhat.com> wrote:

> From: Milan Broz <mbroz@redhat.com>
> 
> When an ioctl is performed on a device with a linear target, simply
> pass it on to the underlying block device.
> 
> Note that the ioctl will pass through the filtering in blkdev_ioctl()
> twice.
>  
> Signed-off-by: Milan Broz <mbroz@redhat.com>
> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
> 
> Index: linux-2.6.17/drivers/md/dm-linear.c
> ===================================================================
> --- linux-2.6.17.orig/drivers/md/dm-linear.c	2006-06-21 17:45:16.000000000 +0100
> +++ linux-2.6.17/drivers/md/dm-linear.c	2006-06-21 18:32:07.000000000 +0100
> @@ -96,14 +96,25 @@ static int linear_status(struct dm_targe
>  	return 0;
>  }
>  
> +static int linear_ioctl(struct dm_target *ti, struct inode *inode,
> +			struct file *filp, unsigned int cmd,
> +			unsigned long arg)
> +{
> +	struct linear_c *lc = (struct linear_c *) ti->private;
> +	struct block_device *bdev = lc->dev->bdev;
> +
> +	return blkdev_ioctl(bdev->bd_inode, filp, cmd, arg);
> +}

but, but..  the blockdev's driver may have decided to use a different ioctl
handler.

We should go through file_operations.ioctl/unlocked_ioctl.