Sequential scrub and resilvers

[mirror_zfs.git] / module / zfs / ddt.c

diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index 00b0a0b9ee2187b1aaf4d3c0b4642725d11d45c7..24516834f0f346300850f8b4fd9422d883c9b2dc 100644 (file)
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -1172,14 +1172,26 @@ ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
 void
 ddt_sync(spa_t *spa, uint64_t txg)
 {
+       dsl_scan_t *scn = spa->spa_dsl_pool->dp_scan;
        dmu_tx_t *tx;
-       zio_t *rio = zio_root(spa, NULL, NULL,
-           ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
+       zio_t *rio;
 
        ASSERT(spa_syncing_txg(spa) == txg);
 
        tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
 
+       rio = zio_root(spa, NULL, NULL,
+           ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
+
+       /*
+        * This function may cause an immediate scan of ddt blocks (see
+        * the comment above dsl_scan_ddt() for details). We set the
+        * scan's root zio here so that we can wait for any scan IOs in
+        * addition to the regular ddt IOs.
+        */
+       ASSERT3P(scn->scn_zio_root, ==, NULL);
+       scn->scn_zio_root = rio;
+
        for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
                ddt_t *ddt = spa->spa_ddt[c];
                if (ddt == NULL)
@@ -1189,6 +1201,7 @@ ddt_sync(spa_t *spa, uint64_t txg)
        }
 
        (void) zio_wait(rio);
+       scn->scn_zio_root = NULL;
 
        dmu_tx_commit(tx);
 }