Gitweb:
https://sourceware.org/git/?p=lvm2.git;a=commitdiff;h=09131e3922ffbea3573...
Commit: 09131e3922ffbea35733aecbc538cdbf415b43ac
Parent: 30c94b0324f070ea3e8b746745572580fc8e0667
Author: David Teigland <teigland(a)redhat.com>
AuthorDate: Thu Sep 20 14:15:49 2018 -0500
Committer: David Teigland <teigland(a)redhat.com>
CommitterDate: Thu Sep 20 14:15:49 2018 -0500
metadata: add comment about negative impact of rounding
---
lib/format_text/format-text.c | 13 +++++++++++++
1 files changed, 13 insertions(+), 0 deletions(-)
diff --git a/lib/format_text/format-text.c b/lib/format_text/format-text.c
index 04a3a8d..e987849 100644
--- a/lib/format_text/format-text.c
+++ b/lib/format_text/format-text.c
@@ -486,7 +486,20 @@ static struct raw_locn *_read_metadata_location_vg(struct device_area
*dev_area,
/*
* Determine offset for new metadata
+ *
+ * Adjusting new offsets to begin on 512 boundaries is fairly new, and metadata
+ * previously begain immediately after the old, without rounding up. The
+ * rounding should have no practical benefit since it does not affect the
+ * actual disk io.
+ *
+ * FIXME: The rounding can have a negative effect: when the current metadata
+ * text size is just below the max, a command to remove something, that
+ * *reduces* the text metadata size, can still be rejected for being too large,
+ * even though it's smaller than the current size. In this case, the user
+ * would need to find something in the VG to remove that uses more text space
+ * to compensate for the increase due to rounding.
*/
+
static uint64_t _next_rlocn_offset(struct raw_locn *rlocn_old, uint64_t old_last, struct
mda_header *mdah, uint64_t mdac_area_start, uint64_t alignment)
{
uint64_t next_start;