vgcreate/vgextend: restrict PVs with mixed block sizes

Avoid having PVs with different logical block sizes in the same VG.
This prevents LVs from having mixed block sizes, which can produce
file system errors.

The new config setting devices/allow_mixed_block_sizes (default 0)
can be changed to 1 to return to the unrestricted mode.

lib/commands/toolcontext.h

@@ -153,6 +153,7 @@ struct cmd_context {
 	unsigned include_shared_vgs:1;		/* report/display cmds can reveal lockd VGs */
 	unsigned include_active_foreign_vgs:1;	/* cmd should process foreign VGs with active LVs */
 	unsigned vg_read_print_access_error:1;	/* print access errors from vg_read */
+	unsigned allow_mixed_block_sizes:1;
 	unsigned force_access_clustered:1;
 	unsigned lockd_gl_disable:1;
 	unsigned lockd_vg_disable:1;

lib/config/config_settings.h

@@ -502,6 +502,11 @@ cfg(devices_allow_changes_with_duplicate_pvs_CFG, "allow_changes_with_duplicate_
 	"Enabling this setting allows the VG to be used as usual even with\n"
 	"uncertain devices.\n")
 
+cfg(devices_allow_mixed_block_sizes_CFG, "allow_mixed_block_sizes", devices_CFG_SECTION, 0, CFG_TYPE_BOOL, 0, vsn(2, 3, 6), NULL, 0, NULL,
+	"Allow PVs in the same VG with different logical block sizes.\n"
+	"When allowed, the user is responsible to ensure that an LV is\n"
+	"using PVs with matching block sizes when necessary.\n")
+
 cfg_array(allocation_cling_tag_list_CFG, "cling_tag_list", allocation_CFG_SECTION, CFG_DEFAULT_UNDEFINED, CFG_TYPE_STRING, NULL, vsn(2, 2, 77), NULL, 0, NULL,
 	"Advise LVM which PVs to use when searching for new space.\n"
 	"When searching for free space to extend an LV, the 'cling' allocation\n"

lib/metadata/metadata-exported.h

@@ -623,6 +623,7 @@ struct pvcreate_params {
 	unsigned is_remove : 1;         /* is removing PVs, not creating */
 	unsigned preserve_existing : 1;
 	unsigned check_failed : 1;
+	unsigned check_consistent_block_size : 1;
 };
 
 struct lvresize_params {

lib/metadata/metadata.c

@@ -751,12 +751,40 @@ int vg_extend_each_pv(struct volume_group *vg, struct pvcreate_params *pp)
 {
 	struct pv_list *pvl;
 	unsigned int max_phys_block_size = 0;
+	unsigned int physical_block_size, logical_block_size;
+	unsigned int prev_lbs = 0;
+	int inconsistent_existing_lbs = 0;
 
 	log_debug_metadata("Adding PVs to VG %s.", vg->name);
 
 	if (vg_bad_status_bits(vg, RESIZEABLE_VG))
 		return_0;
 
+	/*
+	 * Check if existing PVs have inconsistent block sizes.
+	 * If so, do not enforce new devices to be consistent.
+	 */
+	dm_list_iterate_items(pvl, &vg->pvs) {
+		logical_block_size = 0;
+		physical_block_size = 0;
+
+		if (!dev_get_direct_block_sizes(pvl->pv->dev, &physical_block_size, &logical_block_size))
+			continue;
+
+		if (!logical_block_size)
+			continue;
+
+		if (!prev_lbs) {
+			prev_lbs = logical_block_size;
+			continue;
+		}
+		
+		if (prev_lbs != logical_block_size) {
+			inconsistent_existing_lbs = 1;
+			break;
+		}
+	}
+
 	dm_list_iterate_items(pvl, &pp->pvs) {
 		log_debug_metadata("Adding PV %s to VG %s.", pv_dev_name(pvl->pv), vg->name);
 
@@ -767,6 +795,22 @@ int vg_extend_each_pv(struct volume_group *vg, struct pvcreate_params *pp)
 			return 0;
 		}
 
+		logical_block_size = 0;
+		physical_block_size = 0;
+
+		if (!dev_get_direct_block_sizes(pvl->pv->dev, &physical_block_size, &logical_block_size))
+			log_warn("WARNING: PV %s has unknown block size.", pv_dev_name(pvl->pv));
+
+		else if (prev_lbs && logical_block_size && (logical_block_size != prev_lbs)) {
+			if (vg->cmd->allow_mixed_block_sizes || inconsistent_existing_lbs)
+				log_debug("Devices have inconsistent block sizes (%u and %u)", prev_lbs, logical_block_size);
+			else {
+				log_error("Devices have inconsistent logical block sizes (%u and %u).",
+					  prev_lbs, logical_block_size);
+				return 0;
+			}
+		}
+
 		if (!add_pv_to_vg(vg, pv_dev_name(pvl->pv), pvl->pv, 0)) {
 			log_error("PV %s cannot be added to VG %s.",
 				  pv_dev_name(pvl->pv), vg->name);

tools/lvmcmdline.c

@@ -2319,6 +2319,8 @@ static int _get_current_settings(struct cmd_context *cmd)
 
 	cmd->scan_lvs = find_config_tree_bool(cmd, devices_scan_lvs_CFG, NULL);
 
+	cmd->allow_mixed_block_sizes = find_config_tree_bool(cmd, devices_allow_mixed_block_sizes_CFG, NULL);
+
 	/*
 	 * enable_hints is set to 1 if any commands are using hints.
 	 * use_hints is set to 1 if this command doesn't use the hints.

tools/toollib.c

@@ -5355,6 +5355,8 @@ int pvcreate_each_device(struct cmd_context *cmd,
 	struct pv_list *vgpvl;
 	struct device_list *devl;
 	const char *pv_name;
+	unsigned int physical_block_size, logical_block_size;
+	unsigned int prev_pbs = 0, prev_lbs = 0;
 	int must_use_all = (cmd->cname->flags & MUST_USE_ALL_ARGS);
 	int found;
 	unsigned i;
@@ -5394,6 +5396,51 @@ int pvcreate_each_device(struct cmd_context *cmd,
 	dm_list_iterate_items(pd, &pp->arg_devices)
 		pd->dev = dev_cache_get(cmd, pd->name, cmd->filter);
 
+	/*
+	 * Check for consistent block sizes.
+	 */
+	if (pp->check_consistent_block_size) {
+		dm_list_iterate_items(pd, &pp->arg_devices) {
+			if (!pd->dev)
+				continue;
+
+			logical_block_size = 0;
+			physical_block_size = 0;
+
+			if (!dev_get_direct_block_sizes(pd->dev, &physical_block_size, &logical_block_size)) {
+				log_warn("WARNING: Unknown block size for device %s.", dev_name(pd->dev));
+				continue;
+			}
+
+			if (!logical_block_size) {
+				log_warn("WARNING: Unknown logical_block_size for device %s.", dev_name(pd->dev));
+				continue;
+			}
+
+			if (!prev_lbs) {
+				prev_lbs = logical_block_size;
+				prev_pbs = physical_block_size;
+				continue;
+			}
+
+			if (prev_lbs == logical_block_size) {
+				/* Require lbs to match, just warn about unmatching pbs. */
+				if (!cmd->allow_mixed_block_sizes && prev_pbs && physical_block_size &&
+				    (prev_pbs != physical_block_size))
+					log_warn("WARNING: Devices have inconsistent physical block sizes (%u and %u).",
+						  prev_pbs, physical_block_size);
+				continue;
+			}
+
+			if (!cmd->allow_mixed_block_sizes) {
+				log_error("Devices have inconsistent logical block sizes (%u and %u).",
+					  prev_lbs, logical_block_size);
+				log_print("See lvm.conf allow_mixed_block_sizes.");
+				return 0;
+			}
+		}
+	}
+
 	/*
 	 * Use process_each_pv to search all existing PVs and devices.
 	 *

tools/vgcreate.c

@@ -47,6 +47,8 @@ int vgcreate(struct cmd_context *cmd, int argc, char **argv)
 	/* Don't create a new PV on top of an existing PV like pvcreate does. */
 	pp.preserve_existing = 1;
 
+	pp.check_consistent_block_size = 1;
+
 	if (!vgcreate_params_set_defaults(cmd, &vp_def, NULL))
 		return EINVALID_CMD_LINE;
 	vp_def.vg_name = vg_name;