[PATCH 3/3] Tools: hv: vssdaemon: thaw everything in case of freeze failure

[Vitaly Kuznetsov <vkuznets@redhat.com>]

If one or more filesystems failed to freeze we need to thaw everything as
host doing backup won't issue THAW request after we return HV_E_FAIL and our
system will remain with frozen filesystems for ever.

There is no track of filesystems we freeze so in case there is some external
tool doing freeze/thaw requests at the same time they will collide with vss
daemon. This issue can be addressed by introducing a freeze/thaw transaction
and keeping track of what was actually frozen

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 tools/hv/hv_vss_daemon.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c
index 7be999a..e98c638 100644
--- a/tools/hv/hv_vss_daemon.c
+++ b/tools/hv/hv_vss_daemon.c
@@ -284,6 +284,12 @@ int main(int argc, char *argv[])
 			error = vss_operate(op);
 			if (error)
 				error = HV_E_FAIL;
+			if (error && op == VSS_OP_FREEZE) {
+				/* Need to thaw all frozen fylesystems */
+				syslog(LOG_ERR,
+				       "Freeze failed, thaw everything");
+				vss_operate(VSS_OP_THAW);
+			}
 			break;
 		default:
 			syslog(LOG_ERR, "Illegal op:%d\n", op);
-- 
1.9.3