Fix caching of DDT log and BRT

Both DDT log and BRT counters we read on pool import and then only
append or overwrite in full blocks.  We don't need them in DMU or
ARC caches.  Fortunately we have DMU_UNCACHEDIO for this now.

Even more we don't need BRT in non-evictable metadata DMU caches,
since it will likely never fit there, while block the cache from
its original users.  Since DMU_OT_IS_METADATA_CACHED() has no way
to differentiate the new metadata types, mark BRT with storage
type of DMU_OT_DDT_ZAP.  As side effect it will also put it on
dedup device, but that should actually be right.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Alexander Motin <[email protected]>
Closes #17875

include/sys/dmu.h

@@ -126,7 +126,7 @@ typedef enum dmu_object_byteswap {
 	(ot) < DMU_OT_NUMTYPES)
 
 #define	DMU_OT_IS_METADATA_CACHED(ot) (((ot) & DMU_OT_NEWTYPE) ? \
-	B_TRUE : dmu_ot[(ot)].ot_dbuf_metadata_cache)
+	((ot) & DMU_OT_METADATA) != 0 : dmu_ot[(ot)].ot_dbuf_metadata_cache)
 
 /*
  * MDB doesn't have dmu_ot; it defines these macros itself.

module/zfs/brt.c

@@ -454,6 +454,7 @@ brt_vdev_create(spa_t *spa, brt_vdev_t *brtvd, dmu_tx_t *tx)
 	VERIFY(mos_entries != 0);
 	VERIFY0(dnode_hold(spa->spa_meta_objset, mos_entries, brtvd,
 	    &brtvd->bv_mos_entries_dnode));
+	dnode_set_storage_type(brtvd->bv_mos_entries_dnode, DMU_OT_DDT_ZAP);
 	rw_enter(&brtvd->bv_mos_entries_lock, RW_WRITER);
 	brtvd->bv_mos_entries = mos_entries;
 	rw_exit(&brtvd->bv_mos_entries_lock);
@@ -580,13 +581,14 @@ brt_vdev_load(spa_t *spa, brt_vdev_t *brtvd)
 	 */
 	error = dmu_read(spa->spa_meta_objset, brtvd->bv_mos_brtvdev, 0,
 	    MIN(brtvd->bv_size, bvphys->bvp_size) * sizeof (uint16_t),
-	    brtvd->bv_entcount, DMU_READ_NO_PREFETCH);
+	    brtvd->bv_entcount, DMU_READ_NO_PREFETCH | DMU_UNCACHEDIO);
 	if (error != 0)
 		return (error);
 
 	ASSERT(bvphys->bvp_mos_entries != 0);
 	VERIFY0(dnode_hold(spa->spa_meta_objset, bvphys->bvp_mos_entries, brtvd,
 	    &brtvd->bv_mos_entries_dnode));
+	dnode_set_storage_type(brtvd->bv_mos_entries_dnode, DMU_OT_DDT_ZAP);
 	rw_enter(&brtvd->bv_mos_entries_lock, RW_WRITER);
 	brtvd->bv_mos_entries = bvphys->bvp_mos_entries;
 	rw_exit(&brtvd->bv_mos_entries_lock);
@@ -809,7 +811,7 @@ brt_vdev_sync(spa_t *spa, brt_vdev_t *brtvd, dmu_tx_t *tx)
 		uint64_t nblocks = BRT_RANGESIZE_TO_NBLOCKS(brtvd->bv_size);
 		dmu_write(spa->spa_meta_objset, brtvd->bv_mos_brtvdev, 0,
 		    nblocks * BRT_BLOCKSIZE, brtvd->bv_entcount, tx,
-		    DMU_READ_NO_PREFETCH);
+		    DMU_READ_NO_PREFETCH | DMU_UNCACHEDIO);
 		memset(brtvd->bv_bitmap, 0, BT_SIZEOFMAP(nblocks));
 		brtvd->bv_entcount_dirty = FALSE;
 	}

module/zfs/dbuf.c

@@ -446,7 +446,10 @@ static boolean_t
 dbuf_include_in_metadata_cache(dmu_buf_impl_t *db)
 {
 	DB_DNODE_ENTER(db);
-	dmu_object_type_t type = DB_DNODE(db)->dn_type;
+	dnode_t *dn = DB_DNODE(db);
+	dmu_object_type_t type = dn->dn_storage_type;
+	if (type == DMU_OT_NONE)
+		type = dn->dn_type;
 	DB_DNODE_EXIT(db);
 
 	/* Check if this dbuf is one of the types we care about */

module/zfs/ddt_log.c

@@ -222,7 +222,7 @@ ddt_log_begin(ddt_t *ddt, size_t nentries, dmu_tx_t *tx, ddt_log_update_t *dlu)
 
 	VERIFY0(dmu_buf_hold_array_by_dnode(dlu->dlu_dn, offset, length,
 	    B_FALSE, FTAG, &dlu->dlu_ndbp, &dlu->dlu_dbp,
-	    DMU_READ_NO_PREFETCH));
+	    DMU_READ_NO_PREFETCH | DMU_UNCACHEDIO));
 
 	dlu->dlu_tx = tx;
 	dlu->dlu_block = dlu->dlu_offset = 0;
@@ -298,7 +298,8 @@ ddt_log_entry(ddt_t *ddt, ddt_lightweight_entry_t *ddlwe, ddt_log_update_t *dlu)
 	 * we will fill it, and zero it out.
 	 */
 	if (dlu->dlu_offset == 0) {
-		dmu_buf_will_fill(db, dlu->dlu_tx, B_FALSE);
+		dmu_buf_will_fill_flags(db, dlu->dlu_tx, B_FALSE,
+		    DMU_UNCACHEDIO);
 		memset(db->db_data, 0, db->db_size);
 	}
 
@@ -597,7 +598,7 @@ ddt_log_load_one(ddt_t *ddt, uint_t n)
 		for (uint64_t offset = 0; offset < hdr.dlh_length;
 		    offset += dn->dn_datablksz) {
 			err = dmu_buf_hold_by_dnode(dn, offset, FTAG, &db,
-			    DMU_READ_PREFETCH);
+			    DMU_READ_PREFETCH | DMU_UNCACHEDIO);
 			if (err != 0) {
 				dnode_rele(dn, FTAG);
 				ddt_log_empty(ddt, ddl);