Fix 'zfs recv' of non large_dnode send streams

Currently, there is a bug where older send streams without the
DMU_BACKUP_FEATURE_LARGE_DNODE flag are not handled correctly.
The code in receive_object() fails to handle cases where
drro->drr_dn_slots is set to 0, which is always the case when the
sending code does not support this feature flag. This patch fixes
the issue by ensuring that that a value of 0 is treated as
DNODE_MIN_SLOTS.

Tested-by:  DHE <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tom Caputi <[email protected]>
Closes #7617 
Closes #7662 

2 files changed, 13 insertions, 8 deletions

diff --git a/module/zfs/dmu_object.c b/module/zfs/dmu_object.c
index 62ddea905..586a04b16 100644
--- a/module/zfs/dmu_object.c
+++ b/module/zfs/dmu_object.c
@@ -261,6 +261,9 @@ dmu_object_reclaim_dnsize(objset_t *os, uint64_t object, dmu_object_type_t ot,
 	int dn_slots = dnodesize >> DNODE_SHIFT;
 	int err;
 
+	if (dn_slots == 0)
+		dn_slots = DNODE_MIN_SLOTS;
+
 	if (object == DMU_META_DNODE_OBJECT)
 		return (SET_ERROR(EBADF));
 
diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index 3dfe0b73e..ded086087 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -2454,6 +2454,8 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 	dmu_tx_t *tx;
 	uint64_t object;
 	int err;
+	uint8_t dn_slots = drro->drr_dn_slots != 0 ?
+	    drro->drr_dn_slots : DNODE_MIN_SLOTS;
 
 	if (drro->drr_type == DMU_OT_NONE ||
 	    !DMU_OT_IS_VALID(drro->drr_type) ||
@@ -2465,7 +2467,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 	    drro->drr_blksz > spa_maxblocksize(dmu_objset_spa(rwa->os)) ||
 	    drro->drr_bonuslen >
 	    DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(rwa->os))) ||
-	    drro->drr_dn_slots >
+	    dn_slots >
 	    (spa_maxdnodesize(dmu_objset_spa(rwa->os)) >> DNODE_SHIFT))  {
 		return (SET_ERROR(EINVAL));
 	}
@@ -2481,7 +2483,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 		    drro->drr_indblkshift > SPA_MAXBLOCKSHIFT ||
 		    drro->drr_nlevels > DN_MAX_LEVELS ||
 		    drro->drr_nblkptr > DN_MAX_NBLKPTR ||
-		    DN_SLOTS_TO_BONUSLEN(drro->drr_dn_slots) <
+		    DN_SLOTS_TO_BONUSLEN(dn_slots) <
 		    drro->drr_raw_bonuslen)
 			return (SET_ERROR(EINVAL));
 	} else {
@@ -2519,7 +2521,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 
 		if (drro->drr_blksz != doi.doi_data_block_size ||
 		    nblkptr < doi.doi_nblkptr ||
-		    drro->drr_dn_slots != doi.doi_dnodesize >> DNODE_SHIFT ||
+		    dn_slots != doi.doi_dnodesize >> DNODE_SHIFT ||
 		    (rwa->raw &&
 		    (indblksz != doi.doi_metadata_block_size ||
 		    drro->drr_nlevels < doi.doi_indirection))) {
@@ -2540,7 +2542,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 		 * instead.
 		 */
 		if ((rwa->raw && drro->drr_nlevels < doi.doi_indirection) ||
-		    drro->drr_dn_slots != doi.doi_dnodesize >> DNODE_SHIFT) {
+		    dn_slots != doi.doi_dnodesize >> DNODE_SHIFT) {
 			err = dmu_free_long_object(rwa->os, drro->drr_object);
 			if (err != 0)
 				return (SET_ERROR(EINVAL));
@@ -2569,11 +2571,11 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 	 * another object from the previous snapshot. We must free
 	 * these objects before we attempt to allocate the new dnode.
 	 */
-	if (drro->drr_dn_slots > 1) {
+	if (dn_slots > 1) {
 		boolean_t need_sync = B_FALSE;
 
 		for (uint64_t slot = drro->drr_object + 1;
-		    slot < drro->drr_object + drro->drr_dn_slots;
+		    slot < drro->drr_object + dn_slots;
 		    slot++) {
 			dmu_object_info_t slot_doi;
 
@@ -2609,7 +2611,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 		err = dmu_object_claim_dnsize(rwa->os, drro->drr_object,
 		    drro->drr_type, drro->drr_blksz,
 		    drro->drr_bonustype, drro->drr_bonuslen,
-		    drro->drr_dn_slots << DNODE_SHIFT, tx);
+		    dn_slots << DNODE_SHIFT, tx);
 	} else if (drro->drr_type != doi.doi_type ||
 	    drro->drr_blksz != doi.doi_data_block_size ||
 	    drro->drr_bonustype != doi.doi_bonus_type ||
@@ -2618,7 +2620,7 @@ receive_object(struct receive_writer_arg *rwa, struct drr_object *drro,
 		err = dmu_object_reclaim_dnsize(rwa->os, drro->drr_object,
 		    drro->drr_type, drro->drr_blksz,
 		    drro->drr_bonustype, drro->drr_bonuslen,
-		    drro->drr_dn_slots << DNODE_SHIFT, tx);
+		    dn_slots << DNODE_SHIFT, tx);
 	}
 	if (err != 0) {
 		dmu_tx_commit(tx);