dm: do not forward ioctls from logical volumes to the underlying device
A logical volume can map to just part of underlying physical volume.
In this case, it must be treated like a partition.
Based on a patch from Alasdair G Kergon.
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: dm-devel@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index f84c080..9fb18c1 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -368,8 +368,17 @@
static int flakey_ioctl(struct dm_target *ti, unsigned int cmd, unsigned long arg)
{
struct flakey_c *fc = ti->private;
+ struct dm_dev *dev = fc->dev;
+ int r = 0;
- return __blkdev_driver_ioctl(fc->dev->bdev, fc->dev->mode, cmd, arg);
+ /*
+ * Only pass ioctls through if the device sizes match exactly.
+ */
+ if (fc->start ||
+ ti->len != i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT)
+ r = scsi_verify_blk_ioctl(NULL, cmd);
+
+ return r ? : __blkdev_driver_ioctl(dev->bdev, dev->mode, cmd, arg);
}
static int flakey_merge(struct dm_target *ti, struct bvec_merge_data *bvm,