Check max_lv on only place and force the check only for new volume.

We can temporarily violate max_lv during mirror conversion etc.

(If the operation fails, orphan mirror images are visible to administrator
for manual remove for example. Not that this should ever happen:-)

Force limit only for lvcreate (and vg merge) command.

Patch also adds simple max_lv tests into testsuite

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.46 - 
 ================================
+  Force max_lv restriction only for newly created LV.
   Remove unneeded import parameter from lv_create_empty.
   Merge lv_is_displayable and lv_is_visible functions.
   Introduce lv_set_visible & lv_set_invisible functions.

lib/metadata/lv_manip.c

@@ -1804,6 +1804,20 @@ char *generate_lv_name(struct volume_group *vg, const char *format,
 	return buffer;
 }
 
+int vg_max_lv_reached(struct volume_group *vg)
+{
+	if (!vg->max_lv)
+		return 0;
+
+	if (vg->max_lv > vg_visible_lvs(vg))
+		return 0;
+
+	log_verbose("Maximum number of logical volumes (%u) reached "
+		    "in volume group %s", vg->max_lv, vg->name);
+
+	return 1;
+}
+
 /*
  * Create a new empty LV.
  */
@@ -1817,11 +1831,8 @@ struct logical_volume *lv_create_empty(const char *name,
 	struct logical_volume *lv;
 	char dname[NAME_LEN];
 
-	if (vg->max_lv && (vg->max_lv == vg_visible_lvs(vg))) {
-		log_error("Maximum number of logical volumes (%u) reached "
-			  "in volume group %s", vg->max_lv, vg->name);
-		return NULL;
-	}
+	if (vg_max_lv_reached(vg))
+		stack;
 
 	if (strstr(name, "%d") &&
 	    !(name = generate_lv_name(vg, name, dname, sizeof(dname)))) {
@@ -1936,6 +1947,9 @@ int link_lv_to_vg(struct volume_group *vg, struct logical_volume *lv)
 {
 	struct lv_list *lvl;
 
+	if (vg_max_lv_reached(vg))
+		stack;
+
 	if (!(lvl = dm_pool_zalloc(vg->vgmem, sizeof(*lvl))))
 		return_0;
 

lib/metadata/metadata-exported.h

@@ -564,6 +564,11 @@ int vg_check_status(const struct volume_group *vg, uint32_t status);
  */
 unsigned vg_visible_lvs(const struct volume_group *vg);
 
+/*
+ * Check if the VG reached maximal LVs count (if set)
+ */
+int vg_max_lv_reached(struct volume_group *vg);
+
 /*
 * Mirroring functions
 */

lib/metadata/metadata.c

@@ -1528,12 +1528,8 @@ int vg_validate(struct volume_group *vg)
 		r = 0;
 	}
 
-	if (vg->max_lv && (vg->max_lv < vg_visible_lvs(vg))) {
-		log_error("Internal error: Volume group %s contains %u volumes"
-			  " but the limit is set to %u.",
-			  vg->name, vg_visible_lvs(vg), vg->max_lv);
-		r = 0;
-	}
+	if (vg_max_lv_reached(vg))
+		stack;
 
 	return r;
 }

test/t-lvcreate-usage.sh

@@ -55,12 +55,33 @@ grep "^  Invalid stripe size 3\.00 KB\$" err
 case $(lvdisplay $vg) in "") true ;; *) false ;; esac
 
 # Setting max_lv works. (bz490298)
-vgchange -l 4 $vg
+lvremove -ff $vg
+vgchange -l 3 $vg
 lvcreate -l1 -n $lv1 $vg
 lvcreate -l1 -s -n $lv2 $vg/$lv1
 lvcreate -l1 -n $lv3 $vg
 not lvcreate -l1 -n $lv4 $vg
+
+lvremove -ff $vg/$lv3
+lvcreate -l1 -s -n $lv3 $vg/$lv1
+not lvcreate -l1 -n $lv4 $vg
+not lvcreate -l1 -m1 -n $lv4 $vg
+
+lvremove -ff $vg/$lv3
+lvcreate -l1 -m1 -n $lv3 $vg
+lvs
+vgs -o +max_lv
+not lvcreate -l1 -n $lv4 $vg
+not lvcreate -l1 -m1 -n $lv4 $vg
+
+lvconvert -m0 $vg/$lv3
+lvconvert -m2 -i 1 $vg/$lv3
+lvconvert -m1 $vg/$lv3
+
+not vgchange -l 2
+vgchange -l 4
 vgs $vg
+
 lvremove -ff $vg
 vgchange -l 0 $vg
 

test/test-utils.sh

@@ -130,6 +130,7 @@ prepare_devs() {
 	lv1=LV1
 	lv2=LV2
 	lv3=LV3
+	lv4=LV4
 }
 
 disable_dev() {

tools/lvcreate.c

@@ -613,6 +613,12 @@ static int _lvcreate(struct cmd_context *cmd, struct volume_group *vg,
 		return 0;
 	}
 
+	if (vg_max_lv_reached(vg)) {
+		log_error("Maximum number of logical volumes (%u) reached "
+			  "in volume group %s", vg->max_lv, vg->name);
+		return 0;
+	}
+
 	if (lp->mirrors > 1 && !(vg->fid->fmt->features & FMT_SEGMENTS)) {
 		log_error("Metadata does not support mirroring.");
 		return 0;