[dm-devel] [PATCH] 6/5: Don't allow removing suspended devices

[Kevin Corry <kevcorry us ibm com>]

[I posted a similar patch about a week ago, but it seems that it never went
through to dm-devel. Here it is again, with proper reference counting added.]

dm-ioctl.c: Don't allow removing suspended devices. If a device is suspended
and then removed from the ioctl-interface hash-table, there's no longer any
way to reference the device to unsuspend it, and any I/O to that device will
be forever stuck on the pending queue.

--- diff/drivers/md/dm-ioctl.c	2004-06-22 10:23:57.000000000 -0500
+++ source/drivers/md/dm-ioctl.c	2004-06-22 10:30:43.520146736 -0500
@@ -622,6 +622,7 @@
 static int dev_remove(struct dm_ioctl *param, size_t param_size)
 {
 	struct hash_cell *hc;
+	struct mapped_device *md;
 
 	down_write(&_hash_lock);
 	hc = __find_device_hash_cell(param);
@@ -632,6 +633,16 @@
 		return -ENXIO;
 	}
 
+	md = hc->md;
+	dm_get(md);
+	if (dm_suspended(md)) {
+		DMERR("Cannot remove suspended device: %s", hc->name);
+		dm_put(md);
+		up_write(&_hash_lock);
+		return -EBUSY;
+	}
+	dm_put(md);
+
 	__hash_remove(hc);
 	up_write(&_hash_lock);
 	param->data_size = 0;