path: root/sbin/mdconfig
diff options
Diffstat (limited to 'sbin/mdconfig')
2 files changed, 8 insertions, 1 deletions
diff --git a/sbin/mdconfig/mdconfig.8 b/sbin/mdconfig/mdconfig.8
index 0b97ddf1c120..4b2f8e246861 100644
--- a/sbin/mdconfig/mdconfig.8
+++ b/sbin/mdconfig/mdconfig.8
@@ -141,6 +141,9 @@ other devices.
.It Fl o Oo Cm no Oc Ns Ar option
Set or reset options.
.Bl -tag -width indent
+.It Oo Cm no Oc Ns Cm async
+For vnode backed devices: avoid IO_SYNC for increased performance but
+at the risk of deadlocking the entire kernel.
.It Oo Cm no Oc Ns Cm reserve
Allocate and reserve all needed storage from the start, rather than as needed.
.It Oo Cm no Oc Ns Cm cluster
diff --git a/sbin/mdconfig/mdconfig.c b/sbin/mdconfig/mdconfig.c
index 6296da799268..b23e903831ab 100644
--- a/sbin/mdconfig/mdconfig.c
+++ b/sbin/mdconfig/mdconfig.c
@@ -117,7 +117,11 @@ main(int argc, char **argv)
case 'o':
if (cmdline != 2)
- if (!strcmp(optarg, "cluster"))
+ if (!strcmp(optarg, "async"))
+ mdio.md_options |= MD_ASYNC;
+ else if (!strcmp(optarg, "noasync"))
+ mdio.md_options &= ~MD_ASYNC;
+ else if (!strcmp(optarg, "cluster"))
mdio.md_options |= MD_CLUSTER;
else if (!strcmp(optarg, "nocluster"))
mdio.md_options &= ~MD_CLUSTER;