diff options
Diffstat (limited to 'module/zfs/dmu_objset.c')
| -rw-r--r-- | module/zfs/dmu_objset.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c index 53b8a759a..c83ca1b1a 100644 --- a/module/zfs/dmu_objset.c +++ b/module/zfs/dmu_objset.c @@ -859,11 +859,17 @@ dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp, /* * Determine the number of levels necessary for the meta-dnode - * to contain DN_MAX_OBJECT dnodes. + * to contain DN_MAX_OBJECT dnodes. Note that in order to + * ensure that we do not overflow 64 bits, there has to be + * a nlevels that gives us a number of blocks > DN_MAX_OBJECT + * but < 2^64. Therefore, + * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT) (10) must be + * less than (64 - log2(DN_MAX_OBJECT)) (16). */ - while ((uint64_t)mdn->dn_nblkptr << (mdn->dn_datablkshift + + while ((uint64_t)mdn->dn_nblkptr << + (mdn->dn_datablkshift - DNODE_SHIFT + (levels - 1) * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) < - DN_MAX_OBJECT * sizeof (dnode_phys_t)) + DN_MAX_OBJECT) levels++; mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] = |