[lvm-devel] main - pool: limit pmspare to 16GiB

[Zdenek Kabelac]

Gitweb:        https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=f96b45550645e537af5b1a04d4d4476f62d86b63
Commit:        f96b45550645e537af5b1a04d4d4476f62d86b63
Parent:        b4212be2e7e8797bbf8f9a166347659cc39ba075
Author:        Zdenek Kabelac <zkabelac at redhat.com>
AuthorDate:    Fri Jan 29 23:20:18 2021 +0100
Committer:     Zdenek Kabelac <zkabelac at redhat.com>
CommitterDate: Mon Feb 1 12:06:13 2021 +0100

pool: limit pmspare to 16GiB

There is not much point to let allocate more then this size
even when i.e. converted LV is bigger then 16GiB (%extent_size)
ATM neither thin-pool nor cache-pool supports bigger metadata.
---
 lib/metadata/pool_manip.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/metadata/pool_manip.c b/lib/metadata/pool_manip.c
index b67882ef2..1975cb418 100644
--- a/lib/metadata/pool_manip.c
+++ b/lib/metadata/pool_manip.c
@@ -697,6 +697,8 @@ static struct logical_volume *_alloc_pool_metadata_spare(struct volume_group *vg
 int handle_pool_metadata_spare(struct volume_group *vg, uint32_t extents,
 			       struct dm_list *pvh, int poolmetadataspare)
 {
+	/* Max usable size of any spare volume is currently 16GiB rouned to extent size */
+	const uint64_t MAX_SIZE = (UINT64_C(2 * 16) * 1024 * 1024 + vg->extent_size - 1) / vg->extent_size;
 	struct logical_volume *lv = vg->pool_metadata_spare_lv;
 	uint32_t seg_mirrors;
 	struct lv_segment *seg;
@@ -706,8 +708,11 @@ int handle_pool_metadata_spare(struct volume_group *vg, uint32_t extents,
 		/* Find maximal size of metadata LV */
 		dm_list_iterate_items(lvl, &vg->lvs)
 			if (lv_is_pool_metadata(lvl->lv) &&
-			    (lvl->lv->le_count > extents))
+			    (lvl->lv->le_count > extents)) {
 				extents = lvl->lv->le_count;
+				if (extents >= MAX_SIZE)
+					break;
+			}
 
 	if (!poolmetadataspare) {
 		/* TODO: Not showing when lvm.conf would define 'n' ? */
@@ -718,6 +723,9 @@ int handle_pool_metadata_spare(struct volume_group *vg, uint32_t extents,
 		return 1;
 	}
 
+	if (extents > MAX_SIZE)
+		extents = MAX_SIZE;
+
 	if (!lv) {
 		if (!_alloc_pool_metadata_spare(vg, extents, pvh))
 			return_0;