DragonFlyBSD

I investigated this issue a bit and found that the extra 1 in BOOT inode number was caused by
hammer2_inode_create_pfs() on line 1016 (see below):

 995         /*
 996          * Locate an unused key in the collision space.
 997          */
 998         {
 999                 hammer2_xop_scanlhc_t *sxop;
1000                 hammer2_key_t lhcbase;
1001 
1002                 lhcbase = lhc;
1003                 sxop = hammer2_xop_alloc(pip, HAMMER2_XOP_MODIFYING);
1004                 sxop->lhc = lhc;
1005                 hammer2_xop_start(&sxop->head, &hammer2_scanlhc_desc);
1006                 while ((error = hammer2_xop_collect(&sxop->head, 0)) == 0) {
1007                         if (lhc != sxop->head.cluster.focus->bref.key)
1008                                 break;
1009                         ++lhc;
1010                 }
1011                 hammer2_xop_retire(&sxop->head, HAMMER2_XOPMASK_VOP);
1012 
1013                 if (error) {
1014                         if (error != HAMMER2_ERROR_ENOENT)
1015                                 goto done2;
1016                         ++lhc;  // <-- THIS
1017                         error = 0;
1018                 }
1019                 if ((lhcbase ^ lhc) & ~HAMMER2_DIRHASH_LOMASK) {
1020                         error = HAMMER2_ERROR_ENOSPC;
1021                         goto done2;
1022                 }
1023         }

It looks to me that the ++lhc is unnecessary, because the returned code is
HAMMER2_ERROR_ENOENT which indicates the inode number could be used.
But I'm not sure why that ++lhc is needed.

So with hammer2 pfs-create BOOT, the created BOOT PFS has inode number
0xd9b36ce135528000 + 1, due to the ++lhc above.

However with newfs_hammer2 -L BOOT, the inode number would be 0xd9b36ce135528000,
the same as hammer2 hash BOOT.