Fix masking of SP-GiST pages during xlog consistency check

spg_mask() didn't take into account that pd_lower equal to SizeOfPageHeaderData
is still valid value.  This commit fixes that.  Backpatch to 11, where
spg_mask() pg_lower check was introduced.

Reported-by: Michael Paquier
Discussion: https://postgr.es/m/20200615131405.GM52676%40paquier.xyz
Backpatch-through: 11

diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
index ebe6ae8715b92ac4b63a2f3e449ace400853d65c..6bebaaf0895022839713991e811c3c7db201c990 100644 (file)
--- a/src/backend/access/spgist/spgxlog.c
+++ b/src/backend/access/spgist/spgxlog.c
@@ -1008,6 +1008,6 @@ spg_mask(char *pagedata, BlockNumber blkno)
     * Mask the unused space, but only if the page's pd_lower appears to have
     * been set correctly.
     */
-   if (pagehdr->pd_lower > SizeOfPageHeaderData)
+   if (pagehdr->pd_lower >= SizeOfPageHeaderData)
        mask_unused_space(page);
 }