Fix for bug 677739: removing final exclusive cmirror snapshot,

results in clvmd deadlock

When a logical volume is activated exclusively in a cluster, the
local (non-cluster-aware) target is used.  However, when creating
a snapshot on the exclusive LV, the resulting suspend/resume fails
to load the appropriate device-mapper table - instead loading the
cluster-aware target.

This patch adds an 'exclusive' parameter to the pertinent resume
functions to allow for the right target type to be loaded.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.85 - 
 ===================================
+  Fix to make resuming exclusive cluster mirror use local target type.
 
 Version 2.02.84 - 9th February 2011
 ===================================

daemons/clvmd/lvm-functions.c

@@ -399,7 +399,7 @@ error:
 /* Resume the LV if it was active */
 static int do_resume_lv(char *resource, unsigned char lock_flags)
 {
-	int oldmode;
+	int oldmode, origin_only, exclusive;
 
 	/* Is it open ? */
 	oldmode = get_current_lock(resource);
@@ -407,8 +407,10 @@ static int do_resume_lv(char *resource, unsigned char lock_flags)
 		DEBUGLOG("do_resume_lv, lock not already held\n");
 		return 0;	/* We don't need to do anything */
 	}
+	origin_only = (lock_flags & LCK_ORIGIN_ONLY_MODE) ? 1 : 0;
+	exclusive = (oldmode == LCK_EXCL) ? 1 : 0;
 
-	if (!lv_resume_if_active(cmd, resource, (lock_flags & LCK_ORIGIN_ONLY_MODE) ? 1 : 0))
+	if (!lv_resume_if_active(cmd, resource, origin_only, exclusive))
 		return EIO;
 
 	return 0;

lib/activate/activate.c

@@ -1156,8 +1156,18 @@ int lv_suspend(struct cmd_context *cmd, const char *lvid_s)
 }
 ***********/
 
+ /*
+  * _lv_resume
+  * @cmd
+  * @lvid_s
+  * @origin_only
+  * @exclusive:  This parameter only has an affect in cluster-context.
+  *		 It forces local target type to be used (instead of
+  *		 cluster-aware type).
+  * @error_if_not_active
+  */
 static int _lv_resume(struct cmd_context *cmd, const char *lvid_s,
-		      unsigned origin_only,
+		      unsigned origin_only, unsigned exclusive,
 		      int error_if_not_active)
 {
 	struct logical_volume *lv;
@@ -1189,6 +1199,14 @@ static int _lv_resume(struct cmd_context *cmd, const char *lvid_s,
 		goto out;
 	}
 
+	/*
+	 * When targets are activated exclusively in a cluster, the
+	 * non-clustered target should be used.  This only happens
+	 * if ACTIVATE_EXCL is set in lv->status.
+	 */
+	if (exclusive)
+		lv->status |= ACTIVATE_EXCL;
+
 	if (!_lv_activate_lv(lv, origin_only))
 		goto_out;
 
@@ -1206,14 +1224,15 @@ out:
 }
 
 /* Returns success if the device is not active */
-int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only)
+int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s,
+			unsigned origin_only, unsigned exclusive)
 {
-	return _lv_resume(cmd, lvid_s, origin_only, 0);
+	return _lv_resume(cmd, lvid_s, origin_only, exclusive, 0);
 }
 
 int lv_resume(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only)
 {
-	return _lv_resume(cmd, lvid_s, origin_only, 1);
+	return _lv_resume(cmd, lvid_s, origin_only, 0, 1);
 }
 
 static int _lv_has_open_snapshots(struct logical_volume *lv)

lib/activate/activate.h

@@ -56,7 +56,8 @@ void activation_exit(void);
 /* int lv_suspend(struct cmd_context *cmd, const char *lvid_s); */
 int lv_suspend_if_active(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only);
 int lv_resume(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only);
-int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s, unsigned origin_only);
+int lv_resume_if_active(struct cmd_context *cmd, const char *lvid_s,
+			unsigned origin_only, unsigned exclusive);
 int lv_activate(struct cmd_context *cmd, const char *lvid_s, int exclusive);
 int lv_activate_with_filter(struct cmd_context *cmd, const char *lvid_s,
 			    int exclusive);

lib/locking/file_locking.c

@@ -293,7 +293,7 @@ static int _file_lock_resource(struct cmd_context *cmd, const char *resource,
 		switch (flags & LCK_TYPE_MASK) {
 		case LCK_UNLOCK:
 			log_very_verbose("Unlocking LV %s%s", resource, origin_only ? " without snapshots" : "");
-			if (!lv_resume_if_active(cmd, resource, origin_only))
+			if (!lv_resume_if_active(cmd, resource, origin_only, 0))
 				return 0;
 			break;
 		case LCK_NULL:

lib/locking/no_locking.c

@@ -46,7 +46,7 @@ static int _no_lock_resource(struct cmd_context *cmd, const char *resource,
 		case LCK_NULL:
 			return lv_deactivate(cmd, resource);
 		case LCK_UNLOCK:
-			return lv_resume_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1: 0);
+			return lv_resume_if_active(cmd, resource, (flags & LCK_ORIGIN_ONLY) ? 1: 0, 0);
 		case LCK_READ:
 			return lv_activate_with_filter(cmd, resource, 0);
 		case LCK_WRITE: