vgreduce --removemissing to remove missing PVs & deps & make VG consistent

lib/metadata/lv_manip.c

@@ -33,11 +33,13 @@ static void _put_extents(struct lv_segment *seg)
 
 	for (s = 0; s < seg->stripes; s++) {
 		pv = seg->area[s].pv;
-		count = seg->len / seg->stripes;
 
+		if (pv) {
+			count = seg->len / seg->stripes;
 			assert(pv->pe_alloc_count >= count);
 			pv->pe_alloc_count -= count;
 		}
+	}
 }
 
 static struct lv_segment *_alloc_segment(struct pool *mem, uint32_t stripes)

lib/metadata/metadata.c

@@ -318,6 +318,18 @@ struct pv_list *find_pv_in_vg(struct volume_group *vg, const char *pv_name)
 	return NULL;
 }
 
+int pv_is_in_vg(struct volume_group *vg, struct physical_volume *pv)
+{
+	struct list *pvh;
+
+	list_iterate(pvh, &vg->pvs) {
+		if (pv == list_item(pvh, struct pv_list)->pv)
+			 return 1;
+	}
+
+	return 0;
+}
+
 struct physical_volume *find_pv_in_vg_by_uuid(struct volume_group *vg,
 					      struct id *id)
 {

lib/metadata/metadata.h

@@ -424,6 +424,8 @@ int lv_merge_segments(struct logical_volume *lv);
 int lv_is_origin(const struct logical_volume *lv);
 int lv_is_cow(const struct logical_volume *lv);
 
+int pv_is_in_vg(struct volume_group *vg, struct physical_volume *pv);
+
 struct snapshot *find_cow(const struct logical_volume *lv);
 struct snapshot *find_origin(const struct logical_volume *lv);
 struct list *find_snapshots(const struct logical_volume *lv);

man/vgreduce.8

@@ -4,6 +4,7 @@ vgreduce \- reduce a volume group
 .SH SYNOPSIS
 .B vgreduce
 [\-a/\-\-all] [\-A/\-\-autobackup y/n] [\-d/\-\-debug] [\-h/\-?/\-\-help]
+[\-\-removemissing]
 [\-t/\-\-test]
 [\-v/\-\-verbose] VolumeGroupName
 [PhysicalVolumePath...]
@@ -15,6 +16,22 @@ See \fBlvm\fP for common options.
 .TP
 .I \-a, \-\-all
 Removes all empty physical volumes if none are given on command line.
+.TP
+.I \-\-removemissing
+Removes all missing physical volumes from the volume group and makes 
+the volume group consistent again.  
+
+It's a good idea to run this option with --test first to find out what it 
+would remove before running it for real.  
+
+Any logical volumes and dependent snapshots that were partly on the 
+missing disks get removed completely. This includes those parts 
+that lie on disks that are still present.
+
+If your logical volumes spanned several disks including the ones that are
+lost, you might want to try to salvage data first by activating your
+logical volumes with --partial as described in \fBlvm (8)\fP.
+
 .SH SEE ALSO
 .BR lvm (8), 
 .BR vgextend (8)

tools/args.h

@@ -23,6 +23,7 @@ arg(noheadings_ARG, '\0', "noheadings", NULL)
 arg(segments_ARG, '\0', "segments", NULL)
 arg(units_ARG, '\0', "units", string_arg)
 arg(nosuffix_ARG, '\0', "nosuffix", NULL)
+arg(removemissing_ARG, '\0', "removemissing", NULL)
 
 /* Allow some variations */
 arg(resizable_ARG, '\0', "resizable", yes_no_arg)

tools/commands.h

@@ -678,13 +678,14 @@ xx(vgreduce,
    "\t[-A|--autobackup y|n]\n"
    "\t[-d|--debug]\n"
    "\t[-h|--help]\n"
+   "\t[--removemissing]\n"
    "\t[-t|--test]\n"
    "\t[-v|--verbose]\n"
    "\t[--version]" "\n"
    "\tVolumeGroupName\n"
    "\t[PhysicalVolumePath...]\n",
 
-   all_ARG, autobackup_ARG, test_ARG)
+   all_ARG, autobackup_ARG, removemissing_ARG, test_ARG)
 
 xx(vgremove,
    "Remove volume group(s)",

tools/vgreduce.c

@@ -20,8 +20,154 @@
 
 #include "tools.h"
 
+static int _remove_pv(struct volume_group *vg, struct pv_list *pvl)
+{
+	char uuid[64];
+
+	if (vg->pv_count == 1) {
+		log_error("Volume Groups must always contain at least one PV");
+		return 0;
+	}
+
+	if (!id_write_format(&pvl->pv->id, uuid, sizeof(uuid))) {
+		stack;
+		return 0;
+	}
+
+	log_verbose("Removing PV with UUID %s from VG %s", uuid, vg->name);
+
+	if (pvl->pv->pe_alloc_count) {
+		log_error("LVs still present on PV with UUID %s: Can't remove "
+			  "from VG %s", uuid, vg->name);
+		return 0;
+	}
+
+	vg->free_count -= pvl->pv->pe_count;
+	vg->extent_count -= pvl->pv->pe_count;
+	vg->pv_count--;
+
+	list_del(&pvl->list);
+
+	return 1;
+}
+
+static int _remove_lv(struct cmd_context *cmd, struct logical_volume *lv,
+		      int *list_unsafe)
+{
+	struct snapshot *snap;
+	struct list *snaplist, *snh;
+
+	log_verbose("%s/%s has missing extents: removing (including "
+		    "dependencies)", lv->vg->name, lv->name);
+
+	/* Deactivate if necessary */
+	if (!lv_is_cow(lv)) {
+		log_verbose("Deactivating (if active) logical volume %s",
+			    lv->name);
+
+		if (!lock_vol(cmd, lv->lvid.s,
+			      LCK_LV_DEACTIVATE | LCK_NONBLOCK)) {
+			log_error("Failed to deactivate LV %s", lv->name);
+			return 0;
+		}
+	} else if ((snap = find_cow(lv))) {
+		log_verbose("Deactivating (if active) logical volume %s "
+			    "(origin of %s)", snap->origin->name, lv->name);
+
+		if (!lock_vol(cmd, snap->origin->lvid.s,
+			      LCK_LV_DEACTIVATE | LCK_NONBLOCK)) {
+			log_error("Failed to deactivate LV %s",
+				  snap->origin->name);
+			return 0;
+		}
+
+		/* Use the origin LV */
+		lv = snap->origin;
+	}
+
+	/* Remove snapshot dependencies */
+	if (!(snaplist = find_snapshots(lv))) {
+		stack;
+		return 0;
+	}
+	/* List may be empty */
+	list_iterate(snh, snaplist) {
+		*list_unsafe = 1;	/* May remove caller's lvht! */
+		snap = list_item(snh, struct snapshot_list)->snapshot;
+		if (!vg_remove_snapshot(lv->vg, snap->cow)) {
+			stack;
+			return 0;
+		}
+		log_verbose("Removing LV %s from VG %s", snap->cow->name,
+			    lv->vg->name);
+		if (!lv_remove(lv->vg, snap->cow)) {
+			stack;
+			return 0;
+		}
+	}
+
+	/* Remove the LV itself */
+	log_verbose("Removing LV %s from VG %s", lv->name, lv->vg->name);
+	if (!lv_remove(lv->vg, lv)) {
+		stack;
+		return 0;
+	}
+
+	return 1;
+}
+
+static int _make_vg_consistent(struct cmd_context *cmd, struct volume_group *vg)
+{
+	struct list *pvh, *pvht;
+	struct list *lvh, *lvht;
+	struct pv_list *pvl;
+	struct logical_volume *lv;
+	struct physical_volume *pv;
+	struct lv_segment *seg;
+	unsigned int s;
+	int list_unsafe;
+	struct list *segh;
+
+	/* Deactivate & remove necessary LVs */
+      restart_loop:
+	list_unsafe = 0;	/* Set if we delete a different list-member */
+
+	list_iterate_safe(lvh, lvht, &vg->lvs) {
+		lv = list_item(lvh, struct lv_list)->lv;
+
+		/* Are any segments of this LV on missing PVs? */
+		list_iterate(segh, &lv->segments) {
+			seg = list_item(segh, struct lv_segment);
+			for (s = 0; s < seg->stripes; s++) {
+				pv = seg->area[s].pv;
+				if (!pv || !pv->dev) {
+					if (!_remove_lv(cmd, lv, &list_unsafe)) {
+						stack;
+						return 0;
+					}
+					if (list_unsafe)
+						goto restart_loop;
+				}
+			}
+		}
+	}
+
+	/* Remove missing PVs */
+	list_iterate_safe(pvh, pvht, &vg->pvs) {
+		pvl = list_item(pvh, struct pv_list);
+		if (pvl->pv->dev)
+			continue;
+		if (!_remove_pv(vg, pvl)) {
+			stack;
+			return 0;
+		}
+	}
+
+	return 1;
+}
+
 /* Or take pv_name instead? */
-static int vgreduce_single(struct cmd_context *cmd, struct volume_group *vg,
+static int _vgreduce_single(struct cmd_context *cmd, struct volume_group *vg,
 			    struct physical_volume *pv, void *handle)
 {
 	struct pv_list *pvl;
@@ -72,20 +218,27 @@ static int vgreduce_single(struct cmd_context *cmd, struct volume_group *vg,
 
 	return 0;
 }
+
 int vgreduce(struct cmd_context *cmd, int argc, char **argv)
 {
 	struct volume_group *vg;
 	char *vg_name;
-	int ret;
+	int ret = 1;
 	int consistent = 1;
 
-	if (!argc) {
+	if (!argc & !arg_count(cmd, removemissing_ARG)) {
 		log_error("Please give volume group name and "
 			  "physical volume paths");
 		return EINVALID_CMD_LINE;
 	}
 
-	if (argc == 1 && !arg_count(cmd, all_ARG)) {
+	if (!argc & arg_count(cmd, removemissing_ARG)) {
+		log_error("Please give volume group name");
+		return EINVALID_CMD_LINE;
+	}
+
+	if (argc == 1 && !arg_count(cmd, all_ARG)
+	    && !arg_count(cmd, removemissing_ARG)) {
 		log_error("Please enter physical volume paths or option -a");
 		return EINVALID_CMD_LINE;
 	}
@@ -96,6 +249,11 @@ int vgreduce(struct cmd_context *cmd, int argc, char **argv)
 		return EINVALID_CMD_LINE;
 	}
 
+	if (argc > 1 && arg_count(cmd, removemissing_ARG)) {
+		log_error("Please only specify the volume group");
+		return EINVALID_CMD_LINE;
+	}
+
 	vg_name = argv[0];
 	argv++;
 	argc--;
@@ -106,12 +264,57 @@ int vgreduce(struct cmd_context *cmd, int argc, char **argv)
 		return ECMD_FAILED;
 	}
 
-	if (!(vg = vg_read(cmd, vg_name, &consistent)) || !consistent) {
+	if ((!(vg = vg_read(cmd, vg_name, &consistent)) || !consistent) &&
+	    !arg_count(cmd, removemissing_ARG)) {
 		log_error("Volume group \"%s\" doesn't exist", vg_name);
 		unlock_vg(cmd, vg_name);
 		return ECMD_FAILED;
 	}
 
+	if (arg_count(cmd, removemissing_ARG)) {
+		if (vg && consistent) {
+			log_error("Volume group \"%s\" is already consistent",
+				  vg_name);
+			unlock_vg(cmd, vg_name);
+			return ECMD_FAILED;
+		}
+
+		init_partial(1);
+		consistent = 0;
+		if (!(vg = vg_read(cmd, vg_name, &consistent))) {
+			log_error("Volume group \"%s\" not found", vg_name);
+			unlock_vg(cmd, vg_name);
+			return ECMD_FAILED;
+		}
+		if (!archive(vg)) {
+			init_partial(0);
+			unlock_vg(cmd, vg_name);
+			return ECMD_FAILED;
+		}
+
+		if (!_make_vg_consistent(cmd, vg)) {
+			init_partial(0);
+			unlock_vg(cmd, vg_name);
+			return ECMD_FAILED;
+		}
+
+		init_partial(0);
+
+		vg->status &= ~PARTIAL_VG;
+		vg->status |= LVM_WRITE;
+
+		if (!vg_write(vg)) {
+			log_error("Failed to write out a consistent VG for %s",
+				  vg_name);
+			unlock_vg(cmd, vg_name);
+			return ECMD_FAILED;
+		}
+
+		backup(vg);
+
+		log_print("Wrote out consistent volume group %s", vg_name);
+
+	} else {
 		if (vg->status & EXPORTED_VG) {
 			log_error("Volume group \"%s\" is exported", vg->name);
 			unlock_vg(cmd, vg_name);
@@ -125,14 +328,18 @@ int vgreduce(struct cmd_context *cmd, int argc, char **argv)
 		}
 
 		if (!(vg->status & RESIZEABLE_VG)) {
-		log_error("Volume group \"%s\" is not reducable", vg_name);
+			log_error("Volume group \"%s\" is not reducible",
+				  vg_name);
 			unlock_vg(cmd, vg_name);
 			return ECMD_FAILED;
 		}
 
-	/* FIXME: Pass private structure through to all these functions */
+		/* FIXME: Pass private struct through to all these functions */
 		/* and update in batch here? */
-	ret = process_each_pv(cmd, argc, argv, vg, NULL, vgreduce_single);
+		ret = process_each_pv(cmd, argc, argv, vg, NULL,
+				      _vgreduce_single);
+
+	}
 
 	unlock_vg(cmd, vg_name);
 

tools/vgsplit.c

@@ -49,18 +49,6 @@ static int _move_pv(struct volume_group *vg_from, struct volume_group *vg_to,
 	return 1;
 }
 
-static int _pv_is_in_vg(struct volume_group *vg, struct physical_volume *pv)
-{
-	struct list *pvh;
-
-	list_iterate(pvh, &vg->pvs) {
-		if (pv == list_item(pvh, struct pv_list)->pv)
-			 return 1;
-	}
-
-	return 0;
-}
-
 static int _move_lvs(struct volume_group *vg_from, struct volume_group *vg_to)
 {
 	struct list *lvh, *lvht, *segh;
@@ -81,7 +69,7 @@ static int _move_lvs(struct volume_group *vg_from, struct volume_group *vg_to)
 			for (s = 0; s < seg->stripes; s++) {
 				pv = seg->area[s].pv;
 				if (vg_with) {
-					if (!_pv_is_in_vg(vg_with, pv)) {
+					if (!pv_is_in_vg(vg_with, pv)) {
 						log_error("Logical Volume %s "
 							  "split between "
 							  "Volume Groups",
@@ -91,11 +79,11 @@ static int _move_lvs(struct volume_group *vg_from, struct volume_group *vg_to)
 					continue;
 				}
 
-				if (_pv_is_in_vg(vg_from, pv)) {
+				if (pv_is_in_vg(vg_from, pv)) {
 					vg_with = vg_from;
 					continue;
 				}
-				if (_pv_is_in_vg(vg_to, pv)) {
+				if (pv_is_in_vg(vg_to, pv)) {
 					vg_with = vg_to;
 					continue;
 				}