[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: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index dcfbf83..fb9582a 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1273,15 +1273,22 @@
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 @@
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);
}
/*-----------------------------------------------------------------