Commit e90dae1f authored by Milan Broz's avatar Milan Broz Committed by Linus Torvalds
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[PATCH] dm: support ioctls on mapped devices: fix with fake file 



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

ioctl_by_bdev() does set_fs(KERNEL_DS) so it's for ioctls originating
within the kernel and unsuitable here.  We are processing ioctls that
originated in userspace and mapping them to different devices.  Fixing the
existing callers that pass a NULL file struct and consolidating the
fake_file users are separate matters to solve in later patches.

Signed-off-by: default avatarMilan Broz <mbroz@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7006f6ec

drivers/md/dm-linear.c

+7 −1
Original line number Diff line number Diff line
@@ -104,8 +104,14 @@ static int linear_ioctl(struct dm_target *ti, struct inode *inode, 
{

	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 = {

drivers/md/dm-mpath.c

+10 −3
Original line number Diff line number Diff line
@@ -1273,15 +1273,22 @@ static int multipath_ioctl(struct dm_target *ti, struct inode *inode, 
	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;
@@ -1290,8 +1297,8 @@ static int multipath_ioctl(struct dm_target *ti, struct inode *inode, 


	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);

}



/*-----------------------------------------------------------------

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