[PATCH] dm mpath: support ioctls

When an ioctl is performed on a multipath device simply pass it on to the
underlying block device through current_path.  If current path is not yet
selected, select it.

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>

1 files changed, 29 insertions, 1 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 93f701ea87b..14cfdb538ef 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1266,12 +1266,39 @@ error:
         return -EINVAL;
 }
 
+static int multipath_ioctl(struct dm_target *ti, struct inode *inode,
+                           struct file *filp, unsigned int cmd,
+                           unsigned long arg)
+{
+        struct multipath *m = (struct multipath *) ti->private;
+        struct block_device *bdev = NULL;
+        unsigned long flags;
+        int r = 0;
+
+        spin_lock_irqsave(&m->lock, flags);
+
+        if (!m->current_pgpath)
+                __choose_pgpath(m);
+
+        if (m->current_pgpath)
+                bdev = m->current_pgpath->path.dev->bdev;
+
+        if (m->queue_io)
+                r = -EAGAIN;
+        else if (!bdev)
+                r = -EIO;
+
+        spin_unlock_irqrestore(&m->lock, flags);
+
+        return r ? : blkdev_ioctl(bdev->bd_inode, filp, cmd, arg);
+}
+
 /*-----------------------------------------------------------------
  * Module setup
  *---------------------------------------------------------------*/
 static struct target_type multipath_target = {
         .name = "multipath",
-        .version = {1, 0, 4},
+        .version = {1, 0, 5},
         .module = THIS_MODULE,
         .ctr = multipath_ctr,
         .dtr = multipath_dtr,
@@ -1281,6 +1308,7 @@ static struct target_type multipath_target = {
         .resume = multipath_resume,
         .status = multipath_status,
         .message = multipath_message,
+        .ioctl  = multipath_ioctl,
 };
 
 static int __init dm_multipath_init(void)