diff options
Diffstat (limited to 'freebsd/sys/kern/subr_blist.c')
| -rw-r--r-- | freebsd/sys/kern/subr_blist.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/freebsd/sys/kern/subr_blist.c b/freebsd/sys/kern/subr_blist.c index a7d78d86..e5b40e62 100644 --- a/freebsd/sys/kern/subr_blist.c +++ b/freebsd/sys/kern/subr_blist.c @@ -226,17 +226,19 @@ blist_create(daddr_t blocks, int flags) u_daddr_t nodes, radix, skip; int digit; + if (blocks == 0) + panic("invalid block count"); + /* - * Calculate the radix and node count used for scanning. Find the last - * block that is followed by a terminator. + * Calculate the radix and node count used for scanning. */ last_block = blocks - 1; radix = BLIST_BMAP_RADIX; while (radix < blocks) { if (((last_block / radix + 1) & BLIST_META_MASK) != 0) /* - * A terminator will be added. Update last_block to the - * position just before that terminator. + * We must widen the blist to avoid partially + * filled nodes. */ last_block |= radix - 1; radix *= BLIST_META_RADIX; @@ -246,7 +248,9 @@ blist_create(daddr_t blocks, int flags) * Count the meta-nodes in the expanded tree, including the final * terminator, from the bottom level up to the root. */ - nodes = (last_block >= blocks) ? 2 : 1; + nodes = 1; + if (radix - blocks >= BLIST_BMAP_RADIX) + nodes++; last_block /= BLIST_BMAP_RADIX; while (last_block > 0) { nodes += last_block + 1; |