Add dm-integrity support

Create a linear LV with integrity added to it:

lvcreate --type integrity -n Name -L Size VG

or

lvcreate --integrity y -n Name -L Size VG

When creating, --zero y will zero the entire LV.
This is suggested to initialize integrity checksums
and avoid causing read errors in unwritten portions
of the new LV.

Options:

  --integrity internal
  integrity checksum metadata is interleaved with data.

  --integrity external
  integrity checksum metadata on separate LV, allows
  adding integrity to existing LV, or removing integrity.

  --integritymetadata LV
  use the specified LV for external metadata.

  --integritysettings String
  set dm-integrity parameters.

TODO:

- increase allocated LV size by an extra extent, and then
  round provided_data_sectors down to be a multiple of extent size

- add command to remove intregrity from an LV (only for external),
  i.e. lvconvert --integrity none LV

- let integrity be used by raid images

lib/metadata/integrity_manip.c

@@ -131,13 +131,18 @@ int lv_add_integrity(struct logical_volume *lv, const char *arg,
 		     struct integrity_settings *settings)
 {
 	struct cmd_context *cmd = lv->vg->cmd;
+	struct volume_group *vg = lv->vg;
 	struct integrity_settings *set;
 	struct logical_volume *lv_orig;
 	struct logical_volume *meta_lv = NULL;
 	const struct segment_type *segtype;
 	struct lv_segment *seg;
+	uint32_t orig_seg_len; /* extents */
 	int ret;
 
+	seg = first_seg(lv);
+	orig_seg_len = seg->len;
+
 	if (!(segtype = get_segtype_from_string(cmd, SEG_TYPE_NAME_INTEGRITY)))
 		return_0;
 
@@ -187,7 +192,7 @@ int lv_add_integrity(struct logical_volume *lv, const char *arg,
 	if (meta_lv_created)
 		meta_lv = meta_lv_created;
 	else if (meta_name) {
-		if (!(meta_lv = find_lv(lv->vg, meta_name))) {
+		if (!(meta_lv = find_lv(vg, meta_name))) {
 			log_error("LV %s not found.", meta_name);
 			return_0;
 		}
@@ -208,16 +213,38 @@ int lv_add_integrity(struct logical_volume *lv, const char *arg,
 	 */
 
 	if (meta_lv) {
+		struct wipe_params wipe;
+
 		if (!sync_local_dev_names(cmd)) {
 			log_error("Failed to sync local devices.");
 			return 0;
 		}
 
-		if (!activate_and_wipe_lv(meta_lv, 0)) {
-			log_error("LV %s could not be zeroed.", display_lvname(meta_lv));
+		log_verbose("Zeroing LV for integrity metadata");
+
+		if (!lv_is_active(meta_lv)) {
+			if (!activate_lv(cmd, meta_lv)) {
+				log_error("Failed to activate LV %s to zero", display_lvname(meta_lv));
+				return 0;
+			}
+		}
+
+		memset(&wipe, 0, sizeof(wipe));
+		wipe.do_zero = 1;
+		wipe.zero_sectors = 1;
+
+		if (!wipe_lv(meta_lv, wipe)) {
+			log_error("Failed to zero LV for integrity metadata %s", display_lvname(meta_lv));
 			return 0;
 		}
-		seg->integrity_data_sectors = seg->len;
+
+		if (!deactivate_lv(cmd, meta_lv)) {
+			log_error("Failed to deactivate LV %s after zero", display_lvname(meta_lv));
+			return 0;
+		}
+
+		/* orig_seg_len and extent_size are both in sectors */
+		seg->integrity_data_sectors = (orig_seg_len * vg->extent_size);
 		seg->integrity_meta_dev = meta_lv;
 		lv_set_hidden(meta_lv);
 		/* TODO: give meta_lv a suffix? e.g. _imeta */
@@ -257,6 +284,11 @@ int lv_add_integrity(struct logical_volume *lv, const char *arg,
 		lv->status &= ~LV_NOSCAN;
 		lv->status &= ~LV_TEMPORARY;
 	}
+
+	log_debug("Write VG with integrity added to LV");
+
+	if (!vg_write(vg) || !vg_commit(vg))
+		ret = 0;
  out:
 	return ret;
 }

lib/metadata/lv_manip.c

@@ -7736,10 +7736,14 @@ static int _should_wipe_lv(struct lvcreate_params *lp,
 	     first_seg(first_seg(lv)->pool_lv)->zero_new_blocks))
 		return 0;
 
-	if (seg_is_integrity(lp) && (!lp->zero || !(lv->status & LVM_WRITE))) {
-		log_warn("WARNING: --zero not enabled, integrity will not be initialized and may cause read errors.");
-		return 0;
-	}
+	/*
+	 * dm-integrity requires the first sector (integrity superblock) to be
+	 * zero when creating a new integrity device.
+	 * TODO: print a warning or error if the user specifically
+	 * asks for no wiping or zeroing?
+	 */
+	if (seg_is_integrity(lp))
+		return 1;
 
 	/* Cannot zero read-only volume */
 	if ((lv->status & LVM_WRITE) &&
@@ -8232,12 +8236,6 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
 		}
 	}
 
-	if (seg_is_integrity(lp)) {
-		if (!lv_add_integrity(lv, lp->integrity_arg, lp->integrity_meta_lv,
-				      lp->integrity_meta_name, &lp->integrity_settings))
-			return_NULL;
-	}
-
 	lv_set_activation_skip(lv, lp->activation_skip & ACTIVATION_SKIP_SET,
 			       lp->activation_skip & ACTIVATION_SKIP_SET_ENABLED);
 	/*
@@ -8357,27 +8355,25 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
 			goto revert_new_lv;
 		}
 		lv->status &= ~LV_TEMPORARY;
+
+	} else if (seg_is_integrity(lp)) {
+		/*
+		 * Activate the new origin LV so it can be zeroed/wiped
+		 * below before adding integrity.
+		 */
+		lv->status |= LV_TEMPORARY;
+		if (!activate_lv(cmd, lv)) {
+			log_error("Failed to activate new LV for wiping.");
+			goto revert_new_lv;
+		}
+		lv->status &= ~LV_TEMPORARY;
+
 	} else if (!lv_active_change(cmd, lv, lp->activate)) {
 		log_error("Failed to activate new LV %s.", display_lvname(lv));
 		goto deactivate_and_revert_new_lv;
 	}
 
-	if (seg_is_integrity(lp)) {
-		struct wipe_params wipe;
-
-		memset(&wipe, 0, sizeof(wipe));
-		wipe.do_zero = 1;
-		wipe.zero_sectors = first_seg(lv)->integrity_data_sectors;
-
-		if (!_should_wipe_lv(lp, lv, 1))
-			goto_out;
-
-		if (!wipe_lv(lv, wipe))
-			log_error("Failed to zero LV.");
-
-		goto out;
-
-	} else if (_should_wipe_lv(lp, lv, !lp->suppress_zero_warn)) {
+	if (_should_wipe_lv(lp, lv, !lp->suppress_zero_warn)) {
 		if (!wipe_lv(lv, (struct wipe_params)
 			     {
 				     .do_zero = lp->zero,
@@ -8391,6 +8387,55 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
 		}
 	}
 
+	if (seg_is_integrity(lp)) {
+		struct wipe_params wipe;
+
+		log_verbose("Adding integrity to new LV");
+
+		/* Origin is active from zeroing, deactivate to add integrity. */
+
+		if (!deactivate_lv(cmd, lv)) {
+			log_error("Failed to deactivate LV to add integrity");
+			goto revert_new_lv;
+		}
+
+		if (!lv_add_integrity(lv, lp->integrity_arg, lp->integrity_meta_lv,
+				      lp->integrity_meta_name, &lp->integrity_settings))
+			goto revert_new_lv;
+
+		backup(vg);
+
+		/*
+		 * This zeroing is for the final integrity LV, which
+		 * initializes the integrity metadata (checksums).  It's
+		 * different from zeroing the first sector of the integrity
+		 * origin or integrity metadata.
+		 */
+		if (!activate_lv(cmd, lv)) {
+			log_error("Failed to activate LV to zero integrity.");
+			goto out;
+		}
+
+		memset(&wipe, 0, sizeof(wipe));
+		wipe.do_zero = 1;
+		wipe.zero_sectors = first_seg(lv)->integrity_data_sectors;
+
+		log_print("Zeroing integrity checksums (%llu sectors) on LV %s",
+			  (unsigned long long)wipe.zero_sectors, display_lvname(lv));
+
+		if (!wipe_lv(lv, wipe))
+			log_error("Failed to zero integrity metadata.");
+
+		/* If the final requested state is inactive, then deactivate LV. */
+
+		if (!lv_active_change(cmd, lv, lp->activate)) {
+			log_error("Failed to activate new LV %s.", display_lvname(lv));
+			goto deactivate_and_revert_new_lv;
+		}
+
+		goto out;
+	}
+
 	if (seg_is_vdo_pool(lp)) {
 		if (!convert_vdo_pool_lv(lv, &lp->vdo_params, &lp->virtual_extents)) {
 			stack;