[PATCH] dm: support ioctls on mapped devices: fix with fake file

From: Alasdair G Kergon
Date: Fri Jun 23 2006 - 14:37:29 EST


[This applies after all the current dm patches.]


From: Milan Broz <mbroz@xxxxxxxxxx>

The new ioctl code passes the wrong file pointer to the underlying device.
No file pointer is available so make a temporary fake one.

Signed-off-by: Milan Broz <mbroz@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>

Index: linux-2.6.17/drivers/md/dm-mpath.c
===================================================================
--- linux-2.6.17.orig/drivers/md/dm-mpath.c 2006-06-23 19:17:27.000000000 +0100
+++ linux-2.6.17/drivers/md/dm-mpath.c 2006-06-23 19:17:40.000000000 +0100
@@ -1272,15 +1272,22 @@ static int multipath_ioctl(struct dm_tar
struct multipath *m = (struct multipath *) ti->private;
struct block_device *bdev = NULL;
unsigned long flags;
+ struct file fake_file = {};
+ struct dentry fake_dentry = {};
int r = 0;

+ fake_file.f_dentry = &fake_dentry;
+
spin_lock_irqsave(&m->lock, flags);

if (!m->current_pgpath)
__choose_pgpath(m);

- if (m->current_pgpath)
+ if (m->current_pgpath) {
bdev = m->current_pgpath->path.dev->bdev;
+ fake_dentry.d_inode = bdev->bd_inode;
+ fake_file.f_mode = m->current_pgpath->path.dev->mode;
+ }

if (m->queue_io)
r = -EAGAIN;
@@ -1289,8 +1296,8 @@ static int multipath_ioctl(struct dm_tar

spin_unlock_irqrestore(&m->lock, flags);

- return r ? : blkdev_driver_ioctl(bdev->bd_inode, filp, bdev->bd_disk,
- cmd, arg);
+ return r ? : blkdev_driver_ioctl(bdev->bd_inode, &fake_file,
+ bdev->bd_disk, cmd, arg);
}

/*-----------------------------------------------------------------
Index: linux-2.6.17/drivers/md/dm-linear.c
===================================================================
--- linux-2.6.17.orig/drivers/md/dm-linear.c 2006-06-23 19:17:27.000000000 +0100
+++ linux-2.6.17/drivers/md/dm-linear.c 2006-06-23 19:17:40.000000000 +0100
@@ -104,8 +104,14 @@ static int linear_ioctl(struct dm_target
{
struct linear_c *lc = (struct linear_c *) ti->private;
struct block_device *bdev = lc->dev->bdev;
+ struct file fake_file = {};
+ struct dentry fake_dentry = {};

- return blkdev_driver_ioctl(bdev->bd_inode, filp, bdev->bd_disk, cmd, arg);
+ fake_file.f_mode = lc->dev->mode;
+ fake_file.f_dentry = &fake_dentry;
+ fake_dentry.d_inode = bdev->bd_inode;
+
+ return blkdev_driver_ioctl(bdev->bd_inode, &fake_file, bdev->bd_disk, cmd, arg);
}

static struct target_type linear_target = {
-
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