Introduce origin_from_cow()

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.03 - 
 ===================================
+  Introduce origin_from_cow().
   pvremove without -f now fails if there's no PV label.
   Support lvconvert -s.
   Suppress locking library load failure message if --ignorelockingfailure.

lib/metadata/metadata.h

@@ -538,8 +538,12 @@ int lv_is_cow(const struct logical_volume *lv);
 
 int pv_is_in_vg(struct volume_group *vg, struct physical_volume *pv);
 
+/* Given a cow LV, return return the snapshot lv_segment that uses it */
 struct lv_segment *find_cow(const struct logical_volume *lv);
 
+/* Given a cow LV, return its origin */
+struct logical_volume *origin_from_cow(const struct logical_volume *lv);
+
 int vg_add_snapshot(struct format_instance *fid, const char *name,
 		    struct logical_volume *origin, struct logical_volume *cow,
 		    union lvid *lvid, uint32_t extent_count,

lib/metadata/snapshot_manip.c

@@ -34,6 +34,12 @@ struct lv_segment *find_cow(const struct logical_volume *lv)
 	return lv->snapshot;
 }
 
+/* Given a cow LV, return its origin */
+struct logical_volume *origin_from_cow(const struct logical_volume *lv)
+{
+	return lv->snapshot->origin;
+}
+
 int vg_add_snapshot(struct format_instance *fid, const char *name,
 		    struct logical_volume *origin,
 		    struct logical_volume *cow, union lvid *lvid,

lib/report/report.c

@@ -324,7 +324,6 @@ static int _lvstatus_disp(struct report_handle *rh, struct field *field,
 	const struct logical_volume *lv = (const struct logical_volume *) data;
 	struct lvinfo info;
 	char *repstr;
-	struct lv_segment *snap_seg;
 	float snap_percent;
 
 	if (!(repstr = dm_pool_zalloc(rh->mem, 7))) {
@@ -344,7 +343,7 @@ static int _lvstatus_disp(struct report_handle *rh, struct field *field,
 		repstr[0] = 'v';
 	else if (lv_is_origin(lv))
 		repstr[0] = 'o';
-	else if (find_cow(lv))
+	else if (lv_is_cow(lv))
 		repstr[0] = 's';
 	else
 		repstr[0] = '-';
@@ -377,8 +376,8 @@ static int _lvstatus_disp(struct report_handle *rh, struct field *field,
 			repstr[4] = 'd';	/* Inactive without table */
 
 		/* Snapshot dropped? */
-		if (info.live_table && (snap_seg = find_cow(lv)) &&
+		if (info.live_table && lv_is_cow(lv) &&
-		    (!lv_snapshot_percent(snap_seg->cow, &snap_percent) ||
+		    (!lv_snapshot_percent(find_cow(lv)->cow, &snap_percent) ||
 		     snap_percent < 0 || snap_percent >= 100)) {
 			repstr[0] = toupper(repstr[0]);
 			if (info.suspended)
@@ -491,10 +490,9 @@ static int _origin_disp(struct report_handle *rh, struct field *field,
 			const void *data)
 {
 	const struct logical_volume *lv = (const struct logical_volume *) data;
-	struct lv_segment *snap_seg;
 
-	if ((snap_seg = find_cow(lv)))
+	if (lv_is_cow(lv))
-		return _string_disp(rh, field, &snap_seg->origin->name);
+		return _string_disp(rh, field, &origin_from_cow(lv)->name);
 
 	field->report_string = "";
 	field->sort_value = (const void *) field->report_string;
@@ -667,11 +665,10 @@ static int _chunksize_disp(struct report_handle *rh, struct field *field,
 			   const void *data)
 {
 	const struct lv_segment *seg = (const struct lv_segment *) data;
-	struct lv_segment *snap_seg;
 	uint64_t size;
 
-	if ((snap_seg = find_cow(seg->lv)))
+	if (lv_is_cow(seg->lv))
-		size = (uint64_t) snap_seg->chunk_size;
+		size = (uint64_t) find_cow(seg->lv)->chunk_size;
 	else
 		size = 0;
 

tools/lvremove.c

@@ -83,7 +83,7 @@ static int lvremove_single(struct cmd_context *cmd, struct logical_volume *lv,
 	}
 
 	if (lv_is_cow(lv)) {
-		origin = find_cow(lv)->origin;
+		origin = origin_from_cow(lv);
 		log_verbose("Removing snapshot %s", lv->name);
 		if (!vg_remove_snapshot(lv)) {
 			stack;

tools/lvresize.c

@@ -116,7 +116,6 @@ static int _lvresize(struct cmd_context *cmd, struct lvresize_params *lp)
 {
 	struct volume_group *vg;
 	struct logical_volume *lv;
-	struct lv_segment *snap_seg;
 	struct lvinfo info;
 	uint32_t stripesize_extents = 0;
 	uint32_t seg_stripes = 0, seg_stripesize = 0, seg_size = 0;
@@ -521,8 +520,8 @@ static int _lvresize(struct cmd_context *cmd, struct lvresize_params *lp)
 	backup(vg);
 
 	/* If snapshot, must suspend all associated devices */
-	if ((snap_seg = find_cow(lv)))
+	if (lv_is_cow(lv))
-		lock_lv = snap_seg->origin;
+		lock_lv = origin_from_cow(lv);
 	else
 		lock_lv = lv;
 

tools/lvscan.c

@@ -43,9 +43,9 @@ static int lvscan_single(struct cmd_context *cmd, struct logical_volume *lv,
 					snap_active = 0;
 		}
 		snap_seg = NULL;
-	} else if ((snap_seg = find_cow(lv))) {
+	} else if (lv_is_cow(lv)) {
 		if (inkernel &&
-		    (snap_active = lv_snapshot_percent(snap_seg->cow,
+		    (snap_active = lv_snapshot_percent(find_cow(lv)->cow,
 						       &snap_percent)))
 			if (snap_percent < 0 || snap_percent >= 100)
 				snap_active = 0;

tools/vgchange.c

@@ -198,7 +198,7 @@ static int _vgchange_clustered(struct cmd_context *cmd,
 
 	if (clustered) {
         	list_iterate_items(lvl, &vg->lvs) {
-                	if (lvl->lv->origin_count || lvl->lv->snapshot) {
+                	if (lv_is_origin(lvl->lv) || lv_is_cow(lvl->lv)) {
 				log_error("Volume group %s contains snapshots "
 					  "that are not yet supported.",
 					  vg->name);