[PATCH - v2] LVM: New flag, LV_REBUILD

[Jonathan Brassow <jbrassow@redhat.com>]

Changes from previous:
- New rebuild flag is now written to on-disk LVM metadata
- An additional metadata write/commit is necessary to clear the flag
after a proper resume
- flags.c file updated

 brassow

Add new flag, LV_REBUILD.

Until now, I had been using the LV_NOTSYNCED as a flag to indicate that RAID
sub-LVs needed to be rebuilt.  (The 'rebuild' parameter is then specified in
the DM CTR table.)  However, I don't want to use a flag that gets written to
the LVM metadata... and the LV_NOTSYNCED flag's original meaning does not
suite the purpose adequately.

This patch proposes and uses a new flag, LV_REBUILD.


Index: LVM2/lib/metadata/metadata-exported.h
===================================================================
--- LVM2.orig/lib/metadata/metadata-exported.h
+++ LVM2/lib/metadata/metadata-exported.h
@@ -61,7 +61,9 @@
 //#define VIRTUAL		UINT64_C(0x00010000)	/* LV - internal use only */
 #define MIRROR_LOG		UINT64_C(0x00020000)	/* LV */
 #define MIRROR_IMAGE		UINT64_C(0x00040000)	/* LV */
+
 #define LV_NOTSYNCED		UINT64_C(0x00080000)	/* LV */
+#define LV_REBUILD		UINT64_C(0x00100000)	/* LV - internal use only */
 //#define PRECOMMITTED		UINT64_C(0x00200000)	/* VG - internal use only */
 #define CONVERTING		UINT64_C(0x00400000)	/* LV */
 
Index: LVM2/lib/metadata/raid_manip.c
===================================================================
--- LVM2.orig/lib/metadata/raid_manip.c
+++ LVM2/lib/metadata/raid_manip.c
@@ -440,7 +440,7 @@ static int _alloc_image_component(struct
 		return 0;
 	}
 
-	status = LVM_READ | LVM_WRITE | LV_NOTSYNCED | type;
+	status = LVM_READ | LVM_WRITE | LV_REBUILD | type;
 	tmp_lv = lv_create_empty(img_name, NULL, status, ALLOC_INHERIT, lv->vg);
 	if (!tmp_lv) {
 		log_error("Failed to allocate new raid component, %s", img_name);
@@ -569,6 +569,7 @@ static int _alloc_rmeta_for_lv(struct lo
 static int _raid_add_images(struct logical_volume *lv,
 			    uint32_t new_count, struct dm_list *pvs)
 {
+	int rebuild_flag_cleared = 0;
 	uint32_t s;
 	uint32_t old_count = lv_raid_image_count(lv);
 	uint32_t count = new_count - old_count;
@@ -588,7 +589,7 @@ static int _raid_add_images(struct logic
 	 */
 	if (seg_is_linear(seg)) {
 		/* A complete resync will be done, no need to mark each sub-lv */
-		status_mask = ~(LV_NOTSYNCED);
+		status_mask = ~(LV_REBUILD);
 
 		if (!(lvl = dm_pool_alloc(lv->vg->vgmem, sizeof(*lvl)))) {
 			log_error("Memory allocation failed");
@@ -751,6 +752,27 @@ to be left for these sub-lvs.
 		return 0;
 	}
 
+	/*
+	 * Now that the 'REBUILD' has made its way to the kernel, we must
+	 * remove the flag so that the individual devices are not rebuilt
+	 * upon every activation.
+	 */
+	seg = first_seg(lv);
+	for (s = 0; s < seg->area_count; s++) {
+		if ((seg_lv(seg, s)->status & LV_REBUILD) ||
+		    (seg_metalv(seg, s)->status & LV_REBUILD)) {
+			seg_metalv(seg, s)->status &= ~LV_REBUILD;
+			seg_lv(seg, s)->status &= ~LV_REBUILD;
+			rebuild_flag_cleared = 1;
+		}
+	}
+	if (rebuild_flag_cleared &&
+	    (!vg_write(lv->vg) || !vg_commit(lv->vg))) {
+		log_error("Failed to clear REBUILD flag for %s/%s components",
+			  lv->vg->name, lv->name);
+		return 0;
+	}
+
 	return 1;
 
 fail:
@@ -1335,8 +1357,8 @@ static int _convert_mirror_to_raid1(stru
 		log_debug("Adding %s to %s", lvl->lv->name, lv->name);
 
 		/* Images are known to be in-sync */
-		lvl->lv->status &= ~LV_NOTSYNCED;
-		first_seg(lvl->lv)->status &= ~LV_NOTSYNCED;
+		lvl->lv->status &= ~LV_REBUILD;
+		first_seg(lvl->lv)->status &= ~LV_REBUILD;
 		lv_set_hidden(lvl->lv);
 
 		if (!set_lv_segment_area_lv(seg, s, lvl->lv, 0,
Index: LVM2/lib/raid/raid.c
===================================================================
--- LVM2.orig/lib/raid/raid.c
+++ LVM2/lib/raid/raid.c
@@ -183,7 +183,7 @@ static int _raid_add_target_line(struct 
 	}
 
 	for (s = 0; s < seg->area_count; s++)
-		if (seg_lv(seg, s)->status & LV_NOTSYNCED)
+		if (seg_lv(seg, s)->status & LV_REBUILD)
 			rebuilds |= 1 << s;
 
 	if (!dm_tree_node_add_raid_target(node, len, _raid_name(seg),
Index: LVM2/lib/format_text/flags.c
===================================================================
--- LVM2.orig/lib/format_text/flags.c
+++ LVM2/lib/format_text/flags.c
@@ -56,6 +56,7 @@ static const struct flag _lv_flags[] = {
 	{PVMOVE, "PVMOVE", STATUS_FLAG},
 	{LOCKED, "LOCKED", STATUS_FLAG},
 	{LV_NOTSYNCED, "NOTSYNCED", STATUS_FLAG},
+	{LV_REBUILD, "REBUILD", STATUS_FLAG},
 	{RAID, NULL, 0},
 	{RAID_META, NULL, 0},
 	{RAID_IMAGE, NULL, 0},