Handle a failure of all mirror devices but one mirror leg

Index: LVM2-2.02.71-20100714/lib/metadata/mirror.c
===================================================================
@@ -872,71 +872,47 @@ static int _remove_mirror_images(struct 
 		lv->status &= ~MIRROR_NOTSYNCED;
 		if (!replace_lv_with_error_segment(lv))
 			return_0;
-	} else if (remove_log) {
+	} else if (remove_log)
 		detached_log_lv = detach_mirror_log(mirrored_seg);
 
+	/*
+	 * The log may be removed due to repair.  If the log
+	 * happens to be a mirrored log, then there is a special
+	 * case we need to consider.  One of the images of a
+	 * mirrored log can fail followed shortly afterwards by
+	 * a failure of the second.  This means that the top-level
+	 * mirror is waiting for writes to the log to finish, but
+	 * they never will unless the mirrored log can be repaired
+	 * or replaced with an error target.  Since both the devices
+	 * have failed, we must replace with error target - it is
+	 * the only way to release the pending writes.
+	 */
+	if (detached_log_lv && lv_is_mirrored(detached_log_lv) &&
+	    (detached_log_lv->status & PARTIAL_LV)) {
+		log_very_verbose("%s being removed due to failures",
+				 detached_log_lv->name);
+
+		if (!replace_lv_with_error_segment(detached_log_lv)) {
+			log_error("Failed error target substitution for %s",
+				  detached_log_lv->name);
+			return 0;
+		}
+
 		/*
-		 * The log may be removed due to repair.  If the log
-		 * happens to be a mirrored log, then there is a special
-		 * case we need to consider.  One of the images of a
-		 * mirrored log can fail followed shortly afterwards by
-		 * a failure of the second.  This means that the top-level
-		 * mirror is waiting for writes to the log to finish, but
-		 * they never will unless the mirrored log can be repaired
-		 * or replaced with an error target.  Since both the devices
-		 * have failed, we must replace with error target - it is
-		 * the only way to release the pending writes.
+		 * Flush all I/Os holded by mirrored log.
 		 */
-		if (detached_log_lv && lv_is_mirrored(detached_log_lv) &&
-		    (detached_log_lv->status & PARTIAL_LV)) {
-			struct lv_segment *seg = first_seg(detached_log_lv);
-
-			log_very_verbose("%s being removed due to failures",
-					 detached_log_lv->name);
-
-			/*
-			 * We are going to replace the mirror with an
-			 * error segment, but before we do, we must remember
-			 * all of the LVs that must be deleted later (i.e.
-			 * the sub-lv's)
-			 */
-			for (m = 0; m < seg->area_count; m++) {
-				seg_lv(seg, m)->status &= ~MIRROR_IMAGE;
-				lv_set_visible(seg_lv(seg, m));
-				if (!(lvl = dm_pool_alloc(lv->vg->cmd->mem,
-							  sizeof(*lvl)))) {
-					log_error("dm_pool_alloc failed");
-					return 0;
-				}
-				lvl->lv = seg_lv(seg, m);
-				dm_list_add(&tmp_orphan_lvs, &lvl->list);
-			}
-
-			if (!replace_lv_with_error_segment(detached_log_lv)) {
-				log_error("Failed error target substitution for %s",
-					  detached_log_lv->name);
-				return 0;
-			}
-
-			if (!vg_write(detached_log_lv->vg)) {
-				log_error("intermediate VG write fail.");
-				return 0;
-			}
-
-			if (!suspend_lv(detached_log_lv->vg->cmd,
-					detached_log_lv)) {
-				log_error("Failed to suspend %s",
-					  detached_log_lv->name);
-				vg_revert(detached_log_lv->vg);
-				return 0;
-			}
-
-			if (!vg_commit(detached_log_lv->vg))
-				return_0;
+		if (!suspend_lv(detached_log_lv->vg->cmd,
+				detached_log_lv)) {
+			log_error("Failed to suspend %s",
+				  detached_log_lv->name);
+			return 0;
+ 		}
 
-			if (!resume_lv(detached_log_lv->vg->cmd,
-				       detached_log_lv))
-					return_0;
+		if (!resume_lv(detached_log_lv->vg->cmd,
+			       detached_log_lv)) {
+			log_error("Failed to resume %s",
+				  detached_log_lv->name);
+			return_0;
 		}
 	}
 

Index: LVM2-2.02.71-20100714/tools/lvconvert.c
===================================================================
@@ -696,6 +696,13 @@ static int _lv_update_mirrored_log(struc
 	int old_log_count;
 	struct logical_volume *log_lv;
 
+	/*
+	 * When log_count is 0, mirrored log doesn't need to be
+	 * updated here but it will be removed later.
+	 */
+	if (!log_count)
+		return 1;
+
 	log_lv = first_seg(_original_lv(lv))->log_lv;
 	if (!log_lv || !(log_lv->status & MIRRORED))
 		return 1;

@@ -705,12 +712,9 @@ static int _lv_update_mirrored_log(struc
 		return 1;
 
 	/* Reducing redundancy of the log */
-	if (log_count)
-		return remove_mirror_images(log_lv, log_count,
-					    is_mirror_image_removable,
-					    operable_pvs, 0U);
-
-	return remove_mirror_log(lv->vg->cmd, lv, operable_pvs);
+	return remove_mirror_images(log_lv, log_count,
+				    is_mirror_image_removable,
+				    operable_pvs, 0U);
 }
 
 static int _lv_update_log_type(struct cmd_context *cmd,