Update to onnv_147

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

diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index 23c37c7ccfd23923c2fdbaed8e466eb740c6e631..56d41083673eba5d2cf9d47baedb63f06e43364e 100644 (file)
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -56,6 +56,11 @@ static scan_cb_t dsl_scan_remove_cb;
 static dsl_syncfunc_t dsl_scan_cancel_sync;
 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
 
+int zfs_top_maxinflight = 32;          /* maximum I/Os per top-level */
+int zfs_resilver_delay = 2;            /* number of ticks to delay resilver */
+int zfs_scrub_delay = 4;               /* number of ticks to delay scrub */
+int zfs_scan_idle = 50;                        /* idle window in clock ticks */
+
 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
@@ -601,8 +606,8 @@ dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
         * done before setting xlateall (similar to dsl_read())
         */
        (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
-           buf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL,
-           &flags, &czb);
+           buf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
+           ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
 }
 
 static boolean_t
@@ -650,6 +655,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
     const zbookmark_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
 {
        dsl_pool_t *dp = scn->scn_dp;
+       int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
        int err;
 
        if (BP_GET_LEVEL(bp) > 0) {
@@ -660,7 +666,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
                err = arc_read_nolock(NULL, dp->dp_spa, bp,
                    arc_getbuf_func, bufp,
-                   ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+                   ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
@@ -683,7 +689,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
                err = arc_read_nolock(NULL, dp->dp_spa, bp,
                    arc_getbuf_func, bufp,
-                   ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+                   ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
@@ -696,7 +702,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
                err = arc_read_nolock(NULL, dp->dp_spa, bp,
                    arc_getbuf_func, bufp,
-                   ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+                   ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
@@ -719,7 +725,7 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
                err = arc_read_nolock(NULL, dp->dp_spa, bp,
                    arc_getbuf_func, bufp,
-                   ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
+                   ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
                if (err) {
                        scn->scn_phys.scn_errors++;
                        return (err);
@@ -727,9 +733,6 @@ dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
 
                osp = (*bufp)->b_data;
 
-               if (DSL_SCAN_IS_SCRUB_RESILVER(scn))
-                       dsl_scan_zil(dp, &osp->os_zil_header);
-
                dsl_scan_visitdnode(scn, ds, osp->os_type,
                    &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
 
@@ -1072,9 +1075,23 @@ dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
 {
        dsl_pool_t *dp = scn->scn_dp;
        dsl_dataset_t *ds;
+       objset_t *os;
 
        VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
 
+       if (dmu_objset_from_ds(ds, &os))
+               goto out;
+
+       /*
+        * Only the ZIL in the head (non-snapshot) is valid.  Even though
+        * snapshots can have ZIL block pointers (which may be the same
+        * BP as in the head), they must be ignored.  So we traverse the
+        * ZIL here, rather than in scan_recurse(), because the regular
+        * snapshot block-sharing rules don't apply to it.
+        */
+       if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds))
+               dsl_scan_zil(dp, &os->os_zil_header);
+
        /*
         * Iterate over the bps in this ds.
         */
@@ -1446,7 +1463,6 @@ dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
                dsl_scan_setup_sync(scn, &func, tx);
        }
 
-
        if (!dsl_scan_active(scn) ||
            spa_sync_pass(dp->dp_spa) > 1)
                return;
@@ -1489,7 +1505,6 @@ dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
        if (scn->scn_phys.scn_state != DSS_SCANNING)
                return;
 
-
        if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
            scn->scn_phys.scn_ddt_class_max) {
                zfs_dbgmsg("doing scan sync txg %llu; "
@@ -1644,8 +1659,9 @@ dsl_scan_scrub_cb(dsl_pool_t *dp,
        spa_t *spa = dp->dp_spa;
        uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
        boolean_t needs_io;
-       int zio_flags = ZIO_FLAG_SCRUB_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
+       int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
        int zio_priority;
+       int scan_delay = 0;
 
        if (phys_birth <= scn->scn_phys.scn_min_txg ||
            phys_birth >= scn->scn_phys.scn_max_txg)
@@ -1658,10 +1674,12 @@ dsl_scan_scrub_cb(dsl_pool_t *dp,
                zio_flags |= ZIO_FLAG_SCRUB;
                zio_priority = ZIO_PRIORITY_SCRUB;
                needs_io = B_TRUE;
+               scan_delay = zfs_scrub_delay;
        } else if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) {
                zio_flags |= ZIO_FLAG_RESILVER;
                zio_priority = ZIO_PRIORITY_RESILVER;
                needs_io = B_FALSE;
+               scan_delay = zfs_resilver_delay;
        }
 
        /* If it's an intent log block, failure is expected. */
@@ -1699,14 +1717,23 @@ dsl_scan_scrub_cb(dsl_pool_t *dp,
        }
 
        if (needs_io && !zfs_no_scrub_io) {
+               vdev_t *rvd = spa->spa_root_vdev;
+               uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
                void *data = zio_data_buf_alloc(size);
 
                mutex_enter(&spa->spa_scrub_lock);
-               while (spa->spa_scrub_inflight >= spa->spa_scrub_maxinflight)
+               while (spa->spa_scrub_inflight >= maxinflight)
                        cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
                spa->spa_scrub_inflight++;
                mutex_exit(&spa->spa_scrub_lock);
 
+               /*
+                * If we're seeing recent (zfs_scan_idle) "important" I/Os
+                * then throttle our workload to limit the impact of a scan.
+                */
+               if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
+                       delay(scan_delay);
+
                zio_nowait(zio_read(NULL, spa, bp, data, size,
                    dsl_scan_scrub_done, NULL, zio_priority,
                    zio_flags, zb));