From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sun, 18 Mar 2018 19:26:17 +0000 (-0700)
Subject: dm - synchronize disk info before returning
X-Git-Tag: v5.3.0~57
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/8a5197dde90812c26b015b39b499a424148e6029

dm - synchronize disk info before returning

* DM now issues a disk_config(NULL) after setting up the disk info
  in order to wait for the probe to complete, otherwise callers
  may race trying to open() the disk device before it is actually
  ready.

* Fixes cryptsetup luksOpen errors which occur due to probe races,
  typically when used in a VM or qemu.

Reported-by: Aaron LI
---

diff --git a/sys/dev/disk/dm/device-mapper.c b/sys/dev/disk/dm/device-mapper.c
index 6a15d99226..c51ce9948f 100644
--- a/sys/dev/disk/dm/device-mapper.c
+++ b/sys/dev/disk/dm/device-mapper.c
@@ -584,7 +584,12 @@ dmsetdiskinfo(struct disk *disk, dm_table_head_t *head)
 	info.d_secpercyl = info.d_secpertrack * info.d_nheads;
 	info.d_ncylinders = dmp_size / info.d_secpercyl;
 
+	/*
+	 * The probe is asynchronous so call disk_config() to
+	 * wait for it to complete.
+	 */
 	disk_setdiskinfo(disk, &info);
+	disk_config(NULL);
 }
 
 /*