libblkid: (btrfs) use BTRFS_NR_SB_LOG_ZONES and rep->zones

Use the BTRFS_NR_SB_LOG_ZONES constant instead of a hardcoded 2 when
calling blkdev_get_zonereport() to be consistent with the rest of the
function that already uses this constant.

Replace the pointer arithmetic (struct blk_zone *)(rep + 1) with the
more readable rep->zones flexible array member access.

Addresses: https://github.com/util-linux/util-linux/pull/3995
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/libblkid/src/superblocks/btrfs.c b/libblkid/src/superblocks/btrfs.c
index 114d348ab40de6e8326861de268c898c7fc57dbf..11434b210c5d8003d32ccdf2d5f48bcd5cb9dd23 100644 (file)
--- a/libblkid/src/superblocks/btrfs.c
+++ b/libblkid/src/superblocks/btrfs.c
@@ -179,12 +179,12 @@ static int sb_log_offset(blkid_probe pr, uint64_t *bytenr_ret)
 
 
        zone_size_sector = pr->zone_size >> SECTOR_SHIFT;
-       rep = blkdev_get_zonereport(pr->fd, zone_num * zone_size_sector, 2);
+       rep = blkdev_get_zonereport(pr->fd, zone_num * zone_size_sector, BTRFS_NR_SB_LOG_ZONES);
        if (!rep) {
                ret = -errno;
                goto out;
        }
-       zones = (struct blk_zone *)(rep + 1);
+       zones = rep->zones;
 
        /*
         * Use the head of the first conventional zone, if the zones