cluster: RHEL6 - mkfs.gfs2: Open the target device with O_EXCL

[Andrew Price]

Gitweb:       
http://git.fedorahosted.org/git/?p=cluster.git;a=commitdiff;h=24e5e65be1c...
Commit:        24e5e65be1c9b8b433edc1723b4e13feba0db8ba
Parent:        80b9ae57170c1c6042375ea5119aea1ec79e3ab4
Author:        Andrew Price <anprice(a)redhat.com&gt;
AuthorDate:    Tue Apr 5 14:38:03 2016 +0100
Committer:     Andrew Price <anprice(a)redhat.com&gt;
CommitterDate: Tue Aug 16 17:34:15 2016 +0100

mkfs.gfs2: Open the target device with O_EXCL

O_EXCL will let local mounters know that the device is busy while
mkfs.gfs2 is running so that they don't try to access it.

Before:
  # mount /dev/vdc /mnt/test
  mount: /dev/vdc: can't read superblock

With O_EXCL:
  # mount /dev/vdc /mnt/test
  mount: /dev/vdc is already mounted or /mnt/test busy

Resolves: rhbz#1291944

Signed-off-by: Andrew Price <anprice(a)redhat.com&gt;
---
 gfs2/mkfs/main_mkfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/gfs2/mkfs/main_mkfs.c b/gfs2/mkfs/main_mkfs.c
index b132af8..03f078e 100644
--- a/gfs2/mkfs/main_mkfs.c
+++ b/gfs2/mkfs/main_mkfs.c
@@ -558,7 +558,7 @@ void main_mkfs(int argc, char *argv[])
 
 	verify_arguments(sdp);
 
-	sdp->device_fd = open(sdp->device_name, O_RDWR | O_CLOEXEC);
+	sdp->device_fd = open(sdp->device_name, O_RDWR | O_CLOEXEC | O_EXCL);
 	if (sdp->device_fd < 0)
 		die( _("can't open device %s: %s\n"),
 		    sdp->device_name, strerror(errno));