#include <sys/sa_impl.h>
#include <sys/zfeature.h>
#include <sys/abd.h>
+#include <sys/range_tree.h>
#ifdef _KERNEL
#include <sys/zfs_vfsops.h>
#endif
+/*
+ * Grand theory statement on scan queue sorting
+ *
+ * Scanning is implemented by recursively traversing all indirection levels
+ * in an object and reading all blocks referenced from said objects. This
+ * results in us approximately traversing the object from lowest logical
+ * offset to the highest. For best performance, we would want the logical
+ * blocks to be physically contiguous. However, this is frequently not the
+ * case with pools given the allocation patterns of copy-on-write filesystems.
+ * So instead, we put the I/Os into a reordering queue and issue them in a
+ * way that will most benefit physical disks (LBA-order).
+ *
+ * Queue management:
+ *
+ * Ideally, we would want to scan all metadata and queue up all block I/O
+ * prior to starting to issue it, because that allows us to do an optimal
+ * sorting job. This can however consume large amounts of memory. Therefore
+ * we continuously monitor the size of the queues and constrain them to 5%
+ * (zfs_scan_mem_lim_fact) of physmem. If the queues grow larger than this
+ * limit, we clear out a few of the largest extents at the head of the queues
+ * to make room for more scanning. Hopefully, these extents will be fairly
+ * large and contiguous, allowing us to approach sequential I/O throughput
+ * even without a fully sorted tree.
+ *
+ * Metadata scanning takes place in dsl_scan_visit(), which is called from
+ * dsl_scan_sync() every spa_sync(). If we have either fully scanned all
+ * metadata on the pool, or we need to make room in memory because our
+ * queues are too large, dsl_scan_visit() is postponed and
+ * scan_io_queues_run() is called from dsl_scan_sync() instead. This implies
+ * that metadata scanning and queued I/O issuing are mutually exclusive. This
+ * allows us to provide maximum sequential I/O throughput for the majority of
+ * I/O's issued since sequential I/O performance is significantly negatively
+ * impacted if it is interleaved with random I/O.
+ *
+ * Implementation Notes
+ *
+ * One side effect of the queued scanning algorithm is that the scanning code
+ * needs to be notified whenever a block is freed. This is needed to allow
+ * the scanning code to remove these I/Os from the issuing queue. Additionally,
+ * we do not attempt to queue gang blocks to be issued sequentially since this
+ * is very hard to do and would have an extremely limitted performance benefit.
+ * Instead, we simply issue gang I/Os as soon as we find them using the legacy
+ * algorithm.
+ *
+ * Backwards compatibility
+ *
+ * This new algorithm is backwards compatible with the legacy on-disk data
+ * structures (and therefore does not require a new feature flag).
+ * Periodically during scanning (see zfs_scan_checkpoint_intval), the scan
+ * will stop scanning metadata (in logical order) and wait for all outstanding
+ * sorted I/O to complete. Once this is done, we write out a checkpoint
+ * bookmark, indicating that we have scanned everything logically before it.
+ * If the pool is imported on a machine without the new sorting algorithm,
+ * the scan simply resumes from the last checkpoint using the legacy algorithm.
+ */
+
typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *,
const zbookmark_phys_t *);
static scan_cb_t dsl_scan_scrub_cb;
-static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
-static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *);
-static boolean_t dsl_scan_restarting(dsl_scan_t *, dmu_tx_t *);
-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 */
+static int scan_ds_queue_compare(const void *a, const void *b);
+static int scan_prefetch_queue_compare(const void *a, const void *b);
+static void scan_ds_queue_clear(dsl_scan_t *scn);
+static boolean_t scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj,
+ uint64_t *txg);
+static void scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg);
+static void scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj);
+static void scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx);
+
+extern int zfs_vdev_async_write_active_min_dirty_percent;
+
+/*
+ * By default zfs will check to ensure it is not over the hard memory
+ * limit before each txg. If finer-grained control of this is needed
+ * this value can be set to 1 to enable checking before scanning each
+ * block.
+ */
+int zfs_scan_strict_mem_lim = B_FALSE;
+
+/*
+ * Maximum number of parallelly executed bytes per leaf vdev. We attempt
+ * to strike a balance here between keeping the vdev queues full of I/Os
+ * at all times and not overflowing the queues to cause long latency,
+ * which would cause long txg sync times. No matter what, we will not
+ * overload the drives with I/O, since that is protected by
+ * zfs_vdev_scrub_max_active.
+ */
+unsigned long zfs_scan_vdev_limit = 4 << 20;
+
+int zfs_scan_issue_strategy = 0;
+int zfs_scan_legacy = B_FALSE; /* don't queue & sort zios, go direct */
+uint64_t zfs_scan_max_ext_gap = 2 << 20; /* in bytes */
+
+/*
+ * fill_weight is non-tunable at runtime, so we copy it at module init from
+ * zfs_scan_fill_weight. Runtime adjustments to zfs_scan_fill_weight would
+ * break queue sorting.
+ */
+int zfs_scan_fill_weight = 3;
+static uint64_t fill_weight;
+
+/* See dsl_scan_should_clear() for details on the memory limit tunables */
+uint64_t zfs_scan_mem_lim_min = 16 << 20; /* bytes */
+uint64_t zfs_scan_mem_lim_soft_max = 128 << 20; /* bytes */
+int zfs_scan_mem_lim_fact = 20; /* fraction of physmem */
+int zfs_scan_mem_lim_soft_fact = 20; /* fraction of mem lim above */
-int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
+int zfs_scrub_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 */
+int zfs_scan_checkpoint_intval = 7200; /* in seconds */
int zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
int zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
-int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
/* max number of blocks to free in a single TXG */
unsigned long zfs_free_max_blocks = 100000;
+/*
+ * We wait a few txgs after importing a pool to begin scanning so that
+ * the import / mounting code isn't held up by scrub / resilver IO.
+ * Unfortunately, it is a bit difficult to determine exactly how long
+ * this will take since userspace will trigger fs mounts asynchronously
+ * and the kernel will create zvol minors asynchronously. As a result,
+ * the value provided here is a bit arbitrary, but represents a
+ * reasonable estimate of how many txgs it will take to finish fully
+ * importing a pool
+ */
+#define SCAN_IMPORT_WAIT_TXGS 5
+
#define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
(scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
};
+/* In core node for the scn->scn_queue. Represents a dataset to be scanned */
+typedef struct {
+ uint64_t sds_dsobj;
+ uint64_t sds_txg;
+ avl_node_t sds_node;
+} scan_ds_t;
+
+/*
+ * This controls what conditions are placed on dsl_scan_sync_state():
+ * SYNC_OPTIONAL) write out scn_phys iff scn_bytes_pending == 0
+ * SYNC_MANDATORY) write out scn_phys always. scn_bytes_pending must be 0.
+ * SYNC_CACHED) if scn_bytes_pending == 0, write out scn_phys. Otherwise
+ * write out the scn_phys_cached version.
+ * See dsl_scan_sync_state for details.
+ */
+typedef enum {
+ SYNC_OPTIONAL,
+ SYNC_MANDATORY,
+ SYNC_CACHED
+} state_sync_type_t;
+
+/*
+ * This struct represents the minimum information needed to reconstruct a
+ * zio for sequential scanning. This is useful because many of these will
+ * accumulate in the sequential IO queues before being issued, so saving
+ * memory matters here.
+ */
+typedef struct scan_io {
+ /* fields from blkptr_t */
+ uint64_t sio_offset;
+ uint64_t sio_blk_prop;
+ uint64_t sio_phys_birth;
+ uint64_t sio_birth;
+ zio_cksum_t sio_cksum;
+ uint32_t sio_asize;
+
+ /* fields from zio_t */
+ int sio_flags;
+ zbookmark_phys_t sio_zb;
+
+ /* members for queue sorting */
+ union {
+ avl_node_t sio_addr_node; /* link into issueing queue */
+ list_node_t sio_list_node; /* link for issuing to disk */
+ } sio_nodes;
+} scan_io_t;
+
+struct dsl_scan_io_queue {
+ dsl_scan_t *q_scn; /* associated dsl_scan_t */
+ vdev_t *q_vd; /* top-level vdev that this queue represents */
+
+ /* trees used for sorting I/Os and extents of I/Os */
+ range_tree_t *q_exts_by_addr;
+ avl_tree_t q_exts_by_size;
+ avl_tree_t q_sios_by_addr;
+
+ /* members for zio rate limiting */
+ uint64_t q_maxinflight_bytes;
+ uint64_t q_inflight_bytes;
+ kcondvar_t q_zio_cv; /* used under vd->vdev_scan_io_queue_lock */
+
+ /* per txg statistics */
+ uint64_t q_total_seg_size_this_txg;
+ uint64_t q_segs_this_txg;
+ uint64_t q_total_zio_size_this_txg;
+ uint64_t q_zios_this_txg;
+};
+
+/* private data for dsl_scan_prefetch_cb() */
+typedef struct scan_prefetch_ctx {
+ refcount_t spc_refcnt; /* refcount for memory management */
+ dsl_scan_t *spc_scn; /* dsl_scan_t for the pool */
+ boolean_t spc_root; /* is this prefetch for an objset? */
+ uint8_t spc_indblkshift; /* dn_indblkshift of current dnode */
+ uint16_t spc_datablkszsec; /* dn_idatablkszsec of current dnode */
+} scan_prefetch_ctx_t;
+
+/* private data for dsl_scan_prefetch() */
+typedef struct scan_prefetch_issue_ctx {
+ avl_node_t spic_avl_node; /* link into scn->scn_prefetch_queue */
+ scan_prefetch_ctx_t *spic_spc; /* spc for the callback */
+ blkptr_t spic_bp; /* bp to prefetch */
+ zbookmark_phys_t spic_zb; /* bookmark to prefetch */
+} scan_prefetch_issue_ctx_t;
+
+static void scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
+ const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue);
+static void scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue,
+ scan_io_t *sio);
+
+static dsl_scan_io_queue_t *scan_io_queue_create(vdev_t *vd);
+static void scan_io_queues_destroy(dsl_scan_t *scn);
+
+static kmem_cache_t *sio_cache;
+
+void
+scan_init(void)
+{
+ /*
+ * This is used in ext_size_compare() to weight segments
+ * based on how sparse they are. This cannot be changed
+ * mid-scan and the tree comparison functions don't currently
+ * have a mechansim for passing additional context to the
+ * compare functions. Thus we store this value globally and
+ * we only allow it to be set at module intiailization time
+ */
+ fill_weight = zfs_scan_fill_weight;
+
+ sio_cache = kmem_cache_create("sio_cache",
+ sizeof (scan_io_t), 0, NULL, NULL, NULL, NULL, NULL, 0);
+}
+
+void
+scan_fini(void)
+{
+ kmem_cache_destroy(sio_cache);
+}
+
+static inline boolean_t
+dsl_scan_is_running(const dsl_scan_t *scn)
+{
+ return (scn->scn_phys.scn_state == DSS_SCANNING);
+}
+
+boolean_t
+dsl_scan_resilvering(dsl_pool_t *dp)
+{
+ return (dsl_scan_is_running(dp->dp_scan) &&
+ dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
+}
+
+static inline void
+sio2bp(const scan_io_t *sio, blkptr_t *bp, uint64_t vdev_id)
+{
+ bzero(bp, sizeof (*bp));
+ DVA_SET_ASIZE(&bp->blk_dva[0], sio->sio_asize);
+ DVA_SET_VDEV(&bp->blk_dva[0], vdev_id);
+ DVA_SET_OFFSET(&bp->blk_dva[0], sio->sio_offset);
+ bp->blk_prop = sio->sio_blk_prop;
+ bp->blk_phys_birth = sio->sio_phys_birth;
+ bp->blk_birth = sio->sio_birth;
+ bp->blk_fill = 1; /* we always only work with data pointers */
+ bp->blk_cksum = sio->sio_cksum;
+}
+
+static inline void
+bp2sio(const blkptr_t *bp, scan_io_t *sio, int dva_i)
+{
+ /* we discard the vdev id, since we can deduce it from the queue */
+ sio->sio_offset = DVA_GET_OFFSET(&bp->blk_dva[dva_i]);
+ sio->sio_asize = DVA_GET_ASIZE(&bp->blk_dva[dva_i]);
+ sio->sio_blk_prop = bp->blk_prop;
+ sio->sio_phys_birth = bp->blk_phys_birth;
+ sio->sio_birth = bp->blk_birth;
+ sio->sio_cksum = bp->blk_cksum;
+}
+
int
dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
{
scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
SPA_FEATURE_ASYNC_DESTROY);
+ bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
+ avl_create(&scn->scn_queue, scan_ds_queue_compare, sizeof (scan_ds_t),
+ offsetof(scan_ds_t, sds_node));
+ avl_create(&scn->scn_prefetch_queue, scan_prefetch_queue_compare,
+ sizeof (scan_prefetch_issue_ctx_t),
+ offsetof(scan_prefetch_issue_ctx_t, spic_avl_node));
+
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
"scrub_func", sizeof (uint64_t), 1, &f);
if (err == 0) {
scn->scn_restart_txg = txg;
zfs_dbgmsg("old-style scrub was in progress; "
"restarting new-style scrub in txg %llu",
- scn->scn_restart_txg);
+ (longlong_t)scn->scn_restart_txg);
/*
* Load the queue obj from the old location so that it
scn->scn_async_destroying) {
spa->spa_errata =
ZPOOL_ERRATA_ZOL_2094_ASYNC_DESTROY;
- return (SET_ERROR(EOVERFLOW));
+ return (EOVERFLOW);
}
bcopy(zaptmp, &scn->scn_phys,
else if (err)
return (err);
- if (scn->scn_phys.scn_state == DSS_SCANNING &&
+ /*
+ * We might be restarting after a reboot, so jump the issued
+ * counter to how far we've scanned. We know we're consistent
+ * up to here.
+ */
+ scn->scn_issued_before_pass = scn->scn_phys.scn_examined;
+
+ if (dsl_scan_is_running(scn) &&
spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
/*
* A new-type scrub was in progress on an old
scn->scn_restart_txg = txg;
zfs_dbgmsg("new-style scrub was modified "
"by old software; restarting in txg %llu",
- scn->scn_restart_txg);
+ (longlong_t)scn->scn_restart_txg);
+ }
+ }
+
+ /* reload the queue into the in-core state */
+ if (scn->scn_phys.scn_queue_obj != 0) {
+ zap_cursor_t zc;
+ zap_attribute_t za;
+
+ for (zap_cursor_init(&zc, dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ (void) zap_cursor_advance(&zc)) {
+ scan_ds_queue_insert(scn,
+ zfs_strtonum(za.za_name, NULL),
+ za.za_first_integer);
}
+ zap_cursor_fini(&zc);
}
spa_scan_stat_init(spa);
void
dsl_scan_fini(dsl_pool_t *dp)
{
- if (dp->dp_scan) {
+ if (dp->dp_scan != NULL) {
+ dsl_scan_t *scn = dp->dp_scan;
+
+ if (scn->scn_taskq != NULL)
+ taskq_destroy(scn->scn_taskq);
+ scan_ds_queue_clear(scn);
+ avl_destroy(&scn->scn_queue);
+ avl_destroy(&scn->scn_prefetch_queue);
+
kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
dp->dp_scan = NULL;
}
}
+static boolean_t
+dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
+{
+ return (scn->scn_restart_txg != 0 &&
+ scn->scn_restart_txg <= tx->tx_txg);
+}
+
+boolean_t
+dsl_scan_scrubbing(const dsl_pool_t *dp)
+{
+ dsl_scan_phys_t *scn_phys = &dp->dp_scan->scn_phys;
+
+ return (scn_phys->scn_state == DSS_SCANNING &&
+ scn_phys->scn_func == POOL_SCAN_SCRUB);
+}
+
+boolean_t
+dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
+{
+ return (dsl_scan_scrubbing(scn->scn_dp) &&
+ scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED);
+}
+
+/*
+ * Writes out a persistent dsl_scan_phys_t record to the pool directory.
+ * Because we can be running in the block sorting algorithm, we do not always
+ * want to write out the record, only when it is "safe" to do so. This safety
+ * condition is achieved by making sure that the sorting queues are empty
+ * (scn_bytes_pending == 0). When this condition is not true, the sync'd state
+ * is inconsistent with how much actual scanning progress has been made. The
+ * kind of sync to be performed is specified by the sync_type argument. If the
+ * sync is optional, we only sync if the queues are empty. If the sync is
+ * mandatory, we do a hard ASSERT to make sure that the queues are empty. The
+ * third possible state is a "cached" sync. This is done in response to:
+ * 1) The dataset that was in the last sync'd dsl_scan_phys_t having been
+ * destroyed, so we wouldn't be able to restart scanning from it.
+ * 2) The snapshot that was in the last sync'd dsl_scan_phys_t having been
+ * superseded by a newer snapshot.
+ * 3) The dataset that was in the last sync'd dsl_scan_phys_t having been
+ * swapped with its clone.
+ * In all cases, a cached sync simply rewrites the last record we've written,
+ * just slightly modified. For the modifications that are performed to the
+ * last written dsl_scan_phys_t, see dsl_scan_ds_destroyed,
+ * dsl_scan_ds_snapshotted and dsl_scan_ds_clone_swapped.
+ */
+static void
+dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx, state_sync_type_t sync_type)
+{
+ int i;
+ spa_t *spa = scn->scn_dp->dp_spa;
+
+ ASSERT(sync_type != SYNC_MANDATORY || scn->scn_bytes_pending == 0);
+ if (scn->scn_bytes_pending == 0) {
+ for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
+ vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
+ dsl_scan_io_queue_t *q = vd->vdev_scan_io_queue;
+
+ if (q == NULL)
+ continue;
+
+ mutex_enter(&vd->vdev_scan_io_queue_lock);
+ ASSERT3P(avl_first(&q->q_sios_by_addr), ==, NULL);
+ ASSERT3P(avl_first(&q->q_exts_by_size), ==, NULL);
+ ASSERT3P(range_tree_first(q->q_exts_by_addr), ==, NULL);
+ mutex_exit(&vd->vdev_scan_io_queue_lock);
+ }
+
+ if (scn->scn_phys.scn_queue_obj != 0)
+ scan_ds_queue_sync(scn, tx);
+ VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
+ DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
+ &scn->scn_phys, tx));
+ bcopy(&scn->scn_phys, &scn->scn_phys_cached,
+ sizeof (scn->scn_phys));
+
+ if (scn->scn_checkpointing)
+ zfs_dbgmsg("finish scan checkpoint");
+
+ scn->scn_checkpointing = B_FALSE;
+ scn->scn_last_checkpoint = ddi_get_lbolt();
+ } else if (sync_type == SYNC_CACHED) {
+ VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
+ DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
+ &scn->scn_phys_cached, tx));
+ }
+}
+
/* ARGSUSED */
static int
dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
{
dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
- if (scn->scn_phys.scn_state == DSS_SCANNING)
+ if (dsl_scan_is_running(scn))
return (SET_ERROR(EBUSY));
return (0);
dsl_pool_t *dp = scn->scn_dp;
spa_t *spa = dp->dp_spa;
- ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
+ ASSERT(!dsl_scan_is_running(scn));
ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
bzero(&scn->scn_phys, sizeof (scn->scn_phys));
scn->scn_phys.scn_func = *funcp;
scn->scn_phys.scn_start_time = gethrestime_sec();
scn->scn_phys.scn_errors = 0;
scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
+ scn->scn_issued_before_pass = 0;
scn->scn_restart_txg = 0;
scn->scn_done_txg = 0;
+ scn->scn_last_checkpoint = 0;
+ scn->scn_checkpointing = B_FALSE;
spa_scan_stat_init(spa);
if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
if (dp->dp_blkstats == NULL) {
dp->dp_blkstats =
vmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
+ mutex_init(&dp->dp_blkstats->zab_lock, NULL,
+ MUTEX_DEFAULT, NULL);
}
- bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
+ bzero(&dp->dp_blkstats->zab_type, sizeof (dp->dp_blkstats->zab_type));
if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
ot = DMU_OT_ZAP_OTHER;
scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
- dsl_scan_sync_state(scn, tx);
+ bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
+
+ dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
spa_history_log_internal(spa, "scan setup", tx,
"func=%u mintxg=%llu maxtxg=%llu",
*funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
}
+/*
+ * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
+ * Can also be called to resume a paused scrub.
+ */
+int
+dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
+{
+ spa_t *spa = dp->dp_spa;
+ dsl_scan_t *scn = dp->dp_scan;
+
+ /*
+ * Purge all vdev caches and probe all devices. We do this here
+ * rather than in sync context because this requires a writer lock
+ * on the spa_config lock, which we can't do from sync context. The
+ * spa_scrub_reopen flag indicates that vdev_open() should not
+ * attempt to start another scrub.
+ */
+ spa_vdev_state_enter(spa, SCL_NONE);
+ spa->spa_scrub_reopen = B_TRUE;
+ vdev_reopen(spa->spa_root_vdev);
+ spa->spa_scrub_reopen = B_FALSE;
+ (void) spa_vdev_state_exit(spa, NULL, 0);
+
+ if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
+ /* got scrub start cmd, resume paused scrub */
+ int err = dsl_scrub_set_pause_resume(scn->scn_dp,
+ POOL_SCRUB_NORMAL);
+ if (err == 0)
+ return (ECANCELED);
+
+ return (SET_ERROR(err));
+ }
+
+ return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
+ dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));
+}
+
/* ARGSUSED */
static void
dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
}
if (scn->scn_phys.scn_queue_obj != 0) {
- VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
+ VERIFY0(dmu_object_free(dp->dp_meta_objset,
scn->scn_phys.scn_queue_obj, tx));
scn->scn_phys.scn_queue_obj = 0;
}
+ scan_ds_queue_clear(scn);
scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
* If we were "restarted" from a stopped state, don't bother
* with anything else.
*/
- if (scn->scn_phys.scn_state != DSS_SCANNING)
+ if (!dsl_scan_is_running(scn)) {
+ ASSERT(!scn->scn_is_sorted);
return;
+ }
- if (complete)
- scn->scn_phys.scn_state = DSS_FINISHED;
- else
- scn->scn_phys.scn_state = DSS_CANCELED;
+ if (scn->scn_is_sorted) {
+ scan_io_queues_destroy(scn);
+ scn->scn_is_sorted = B_FALSE;
+
+ if (scn->scn_taskq != NULL) {
+ taskq_destroy(scn->scn_taskq);
+ scn->scn_taskq = NULL;
+ }
+ }
+
+ scn->scn_phys.scn_state = complete ? DSS_FINISHED : DSS_CANCELED;
if (dsl_scan_restarting(scn, tx))
spa_history_log_internal(spa, "scan aborted, restarting", tx,
"errors=%llu", spa_get_errlog_size(spa));
if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
- mutex_enter(&spa->spa_scrub_lock);
- while (spa->spa_scrub_inflight > 0) {
- cv_wait(&spa->spa_scrub_io_cv,
- &spa->spa_scrub_lock);
- }
- mutex_exit(&spa->spa_scrub_lock);
spa->spa_scrub_started = B_FALSE;
spa->spa_scrub_active = B_FALSE;
if (spa->spa_errata == ZPOOL_ERRATA_ZOL_2094_SCRUB)
spa->spa_errata = 0;
+
+ ASSERT(!dsl_scan_is_running(scn));
}
/* ARGSUSED */
{
dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
- if (scn->scn_phys.scn_state != DSS_SCANNING)
+ if (!dsl_scan_is_running(scn))
return (SET_ERROR(ENOENT));
return (0);
}
dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
dsl_scan_done(scn, B_FALSE, tx);
- dsl_scan_sync_state(scn, tx);
+ dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
}
int
dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
}
-boolean_t
-dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
-{
- if (dsl_scan_scrubbing(scn->scn_dp) &&
- scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED)
- return (B_TRUE);
-
- return (B_FALSE);
-}
-
static int
dsl_scrub_pause_resume_check(void *arg, dmu_tx_t *tx)
{
/* can't pause a scrub when there is no in-progress scrub */
spa->spa_scan_pass_scrub_pause = gethrestime_sec();
scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED;
- dsl_scan_sync_state(scn, tx);
+ dsl_scan_sync_state(scn, tx, SYNC_CACHED);
} else {
ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL);
if (dsl_scan_is_paused_scrub(scn)) {
gethrestime_sec() - spa->spa_scan_pass_scrub_pause;
spa->spa_scan_pass_scrub_pause = 0;
scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
- dsl_scan_sync_state(scn, tx);
+ dsl_scan_sync_state(scn, tx, SYNC_CACHED);
}
}
}
ZFS_SPACE_CHECK_RESERVED));
}
-boolean_t
-dsl_scan_scrubbing(const dsl_pool_t *dp)
-{
- dsl_scan_t *scn = dp->dp_scan;
- if (scn->scn_phys.scn_state == DSS_SCANNING &&
- scn->scn_phys.scn_func == POOL_SCAN_SCRUB)
- return (B_TRUE);
+/* start a new scan, or restart an existing one. */
+void
+dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
+{
+ if (txg == 0) {
+ dmu_tx_t *tx;
+ tx = dmu_tx_create_dd(dp->dp_mos_dir);
+ VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
- return (B_FALSE);
+ txg = dmu_tx_get_txg(tx);
+ dp->dp_scan->scn_restart_txg = txg;
+ dmu_tx_commit(tx);
+ } else {
+ dp->dp_scan->scn_restart_txg = txg;
+ }
+ zfs_dbgmsg("restarting resilver txg=%llu", (longlong_t)txg);
}
-static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
- dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
- dmu_objset_type_t ostype, dmu_tx_t *tx);
-inline __attribute__((always_inline)) static void dsl_scan_visitdnode(
- dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype,
- dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
-
void
dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
{
zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
}
-static uint64_t
-dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
+static int
+scan_ds_queue_compare(const void *a, const void *b)
{
- uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
- if (ds->ds_is_snapshot)
- return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
- return (smt);
+ const scan_ds_t *sds_a = a, *sds_b = b;
+
+ if (sds_a->sds_dsobj < sds_b->sds_dsobj)
+ return (-1);
+ if (sds_a->sds_dsobj == sds_b->sds_dsobj)
+ return (0);
+ return (1);
}
static void
-dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
+scan_ds_queue_clear(dsl_scan_t *scn)
+{
+ void *cookie = NULL;
+ scan_ds_t *sds;
+ while ((sds = avl_destroy_nodes(&scn->scn_queue, &cookie)) != NULL) {
+ kmem_free(sds, sizeof (*sds));
+ }
+}
+
+static boolean_t
+scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, uint64_t *txg)
{
- VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
- DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
- &scn->scn_phys, tx));
+ scan_ds_t srch, *sds;
+
+ srch.sds_dsobj = dsobj;
+ sds = avl_find(&scn->scn_queue, &srch, NULL);
+ if (sds != NULL && txg != NULL)
+ *txg = sds->sds_txg;
+ return (sds != NULL);
}
-extern int zfs_vdev_async_write_active_min_dirty_percent;
+static void
+scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg)
+{
+ scan_ds_t *sds;
+ avl_index_t where;
+
+ sds = kmem_zalloc(sizeof (*sds), KM_SLEEP);
+ sds->sds_dsobj = dsobj;
+ sds->sds_txg = txg;
+
+ VERIFY3P(avl_find(&scn->scn_queue, sds, &where), ==, NULL);
+ avl_insert(&scn->scn_queue, sds, where);
+}
+
+static void
+scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj)
+{
+ scan_ds_t srch, *sds;
+
+ srch.sds_dsobj = dsobj;
+
+ sds = avl_find(&scn->scn_queue, &srch, NULL);
+ VERIFY(sds != NULL);
+ avl_remove(&scn->scn_queue, sds);
+ kmem_free(sds, sizeof (*sds));
+}
+
+static void
+scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx)
+{
+ dsl_pool_t *dp = scn->scn_dp;
+ spa_t *spa = dp->dp_spa;
+ dmu_object_type_t ot = (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) ?
+ DMU_OT_SCAN_QUEUE : DMU_OT_ZAP_OTHER;
+
+ ASSERT0(scn->scn_bytes_pending);
+ ASSERT(scn->scn_phys.scn_queue_obj != 0);
+
+ VERIFY0(dmu_object_free(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, tx));
+ scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, ot,
+ DMU_OT_NONE, 0, tx);
+ for (scan_ds_t *sds = avl_first(&scn->scn_queue);
+ sds != NULL; sds = AVL_NEXT(&scn->scn_queue, sds)) {
+ VERIFY0(zap_add_int_key(dp->dp_meta_objset,
+ scn->scn_phys.scn_queue_obj, sds->sds_dsobj,
+ sds->sds_txg, tx));
+ }
+}
+
+/*
+ * Computes the memory limit state that we're currently in. A sorted scan
+ * needs quite a bit of memory to hold the sorting queue, so we need to
+ * reasonably constrain the size so it doesn't impact overall system
+ * performance. We compute two limits:
+ * 1) Hard memory limit: if the amount of memory used by the sorting
+ * queues on a pool gets above this value, we stop the metadata
+ * scanning portion and start issuing the queued up and sorted
+ * I/Os to reduce memory usage.
+ * This limit is calculated as a fraction of physmem (by default 5%).
+ * We constrain the lower bound of the hard limit to an absolute
+ * minimum of zfs_scan_mem_lim_min (default: 16 MiB). We also constrain
+ * the upper bound to 5% of the total pool size - no chance we'll
+ * ever need that much memory, but just to keep the value in check.
+ * 2) Soft memory limit: once we hit the hard memory limit, we start
+ * issuing I/O to reduce queue memory usage, but we don't want to
+ * completely empty out the queues, since we might be able to find I/Os
+ * that will fill in the gaps of our non-sequential IOs at some point
+ * in the future. So we stop the issuing of I/Os once the amount of
+ * memory used drops below the soft limit (at which point we stop issuing
+ * I/O and start scanning metadata again).
+ *
+ * This limit is calculated by subtracting a fraction of the hard
+ * limit from the hard limit. By default this fraction is 5%, so
+ * the soft limit is 95% of the hard limit. We cap the size of the
+ * difference between the hard and soft limits at an absolute
+ * maximum of zfs_scan_mem_lim_soft_max (default: 128 MiB) - this is
+ * sufficient to not cause too frequent switching between the
+ * metadata scan and I/O issue (even at 2k recordsize, 128 MiB's
+ * worth of queues is about 1.2 GiB of on-pool data, so scanning
+ * that should take at least a decent fraction of a second).
+ */
+static boolean_t
+dsl_scan_should_clear(dsl_scan_t *scn)
+{
+ vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
+ uint64_t mlim_hard, mlim_soft, mused;
+ uint64_t alloc = metaslab_class_get_alloc(spa_normal_class(
+ scn->scn_dp->dp_spa));
+
+ mlim_hard = MAX((physmem / zfs_scan_mem_lim_fact) * PAGESIZE,
+ zfs_scan_mem_lim_min);
+ mlim_hard = MIN(mlim_hard, alloc / 20);
+ mlim_soft = mlim_hard - MIN(mlim_hard / zfs_scan_mem_lim_soft_fact,
+ zfs_scan_mem_lim_soft_max);
+ mused = 0;
+ for (uint64_t i = 0; i < rvd->vdev_children; i++) {
+ vdev_t *tvd = rvd->vdev_child[i];
+ dsl_scan_io_queue_t *queue;
+
+ mutex_enter(&tvd->vdev_scan_io_queue_lock);
+ queue = tvd->vdev_scan_io_queue;
+ if (queue != NULL) {
+ /* #extents in exts_by_size = # in exts_by_addr */
+ mused += avl_numnodes(&queue->q_exts_by_size) *
+ sizeof (range_seg_t) +
+ avl_numnodes(&queue->q_sios_by_addr) *
+ sizeof (scan_io_t);
+ }
+ mutex_exit(&tvd->vdev_scan_io_queue_lock);
+ }
+
+ dprintf("current scan memory usage: %llu bytes\n", (longlong_t)mused);
+
+ if (mused == 0)
+ ASSERT0(scn->scn_bytes_pending);
+
+ /*
+ * If we are above our hard limit, we need to clear out memory.
+ * If we are below our soft limit, we need to accumulate sequential IOs.
+ * Otherwise, we should keep doing whatever we are currently doing.
+ */
+ if (mused >= mlim_hard)
+ return (B_TRUE);
+ else if (mused < mlim_soft)
+ return (B_FALSE);
+ else
+ return (scn->scn_clearing);
+}
static boolean_t
dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb)
/*
* We suspend if:
- * - we have scanned for the maximum time: an entire txg
- * timeout (default 5 sec)
- * or
* - we have scanned for at least the minimum time (default 1 sec
* for scrub, 3 sec for resilver), and either we have sufficient
* dirty data that we are starting to write more quickly
- * (default 30%), or someone is explicitly waiting for this txg
- * to complete.
+ * (default 30%), someone is explicitly waiting for this txg
+ * to complete, or we have used up all of the time in the txg
+ * timeout (default 5 sec).
* or
* - the spa is shutting down because this pool is being exported
* or the machine is rebooting.
+ * or
+ * - the scan queue has reached its memory use limit
*/
- int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
- zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
- uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
+ uint64_t curr_time_ns = gethrtime();
+ uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
+ uint64_t sync_time_ns = curr_time_ns -
+ scn->scn_dp->dp_spa->spa_sync_starttime;
int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
- if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
- (NSEC2MSEC(elapsed_nanosecs) > mintime &&
- (txg_sync_waiting(scn->scn_dp) ||
- dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
- spa_shutting_down(scn->scn_dp->dp_spa)) {
+ int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
+ zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
+
+ if ((NSEC2MSEC(scan_time_ns) > mintime &&
+ (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
+ txg_sync_waiting(scn->scn_dp) ||
+ NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
+ spa_shutting_down(scn->scn_dp->dp_spa) ||
+ (zfs_scan_strict_mem_lim && dsl_scan_should_clear(scn))) {
if (zb) {
dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n",
(longlong_t)zb->zb_objset,
(longlong_t)zb->zb_level,
(longlong_t)zb->zb_blkid);
scn->scn_phys.scn_bookmark = *zb;
+ } else {
+ dsl_scan_phys_t *scnp = &scn->scn_phys;
+
+ dprintf("suspending at at DDT bookmark "
+ "%llx/%llx/%llx/%llx\n",
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
}
- dprintf("suspending at DDT bookmark %llx/%llx/%llx/%llx\n",
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
scn->scn_suspending = B_TRUE;
return (B_TRUE);
}
zil_free(zilog);
}
-/* ARGSUSED */
-static void
-dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
- uint64_t objset, uint64_t object, uint64_t blkid)
+/*
+ * We compare scan_prefetch_issue_ctx_t's based on their bookmarks. The idea
+ * here is to sort the AVL tree by the order each block will be needed.
+ */
+static int
+scan_prefetch_queue_compare(const void *a, const void *b)
{
- zbookmark_phys_t czb;
- arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
- int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
+ const scan_prefetch_issue_ctx_t *spic_a = a, *spic_b = b;
+ const scan_prefetch_ctx_t *spc_a = spic_a->spic_spc;
+ const scan_prefetch_ctx_t *spc_b = spic_b->spic_spc;
- if (zfs_no_scrub_prefetch)
- return;
+ return (zbookmark_compare(spc_a->spc_datablkszsec,
+ spc_a->spc_indblkshift, spc_b->spc_datablkszsec,
+ spc_b->spc_indblkshift, &spic_a->spic_zb, &spic_b->spic_zb));
+}
- if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
- (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
- return;
+static void
+scan_prefetch_ctx_rele(scan_prefetch_ctx_t *spc, void *tag)
+{
+ if (refcount_remove(&spc->spc_refcnt, tag) == 0) {
+ refcount_destroy(&spc->spc_refcnt);
+ kmem_free(spc, sizeof (scan_prefetch_ctx_t));
+ }
+}
+
+static scan_prefetch_ctx_t *
+scan_prefetch_ctx_create(dsl_scan_t *scn, dnode_phys_t *dnp, void *tag)
+{
+ scan_prefetch_ctx_t *spc;
+
+ spc = kmem_alloc(sizeof (scan_prefetch_ctx_t), KM_SLEEP);
+ refcount_create(&spc->spc_refcnt);
+ refcount_add(&spc->spc_refcnt, tag);
+ spc->spc_scn = scn;
+ if (dnp != NULL) {
+ spc->spc_datablkszsec = dnp->dn_datablkszsec;
+ spc->spc_indblkshift = dnp->dn_indblkshift;
+ spc->spc_root = B_FALSE;
+ } else {
+ spc->spc_datablkszsec = 0;
+ spc->spc_indblkshift = 0;
+ spc->spc_root = B_TRUE;
+ }
+
+ return (spc);
+}
+
+static void
+scan_prefetch_ctx_add_ref(scan_prefetch_ctx_t *spc, void *tag)
+{
+ refcount_add(&spc->spc_refcnt, tag);
+}
+
+static boolean_t
+dsl_scan_check_prefetch_resume(scan_prefetch_ctx_t *spc,
+ const zbookmark_phys_t *zb)
+{
+ zbookmark_phys_t *last_zb = &spc->spc_scn->scn_prefetch_bookmark;
+ dnode_phys_t tmp_dnp;
+ dnode_phys_t *dnp = (spc->spc_root) ? NULL : &tmp_dnp;
+
+ if (zb->zb_objset != last_zb->zb_objset)
+ return (B_TRUE);
+ if ((int64_t)zb->zb_object < 0)
+ return (B_FALSE);
+
+ tmp_dnp.dn_datablkszsec = spc->spc_datablkszsec;
+ tmp_dnp.dn_indblkshift = spc->spc_indblkshift;
+
+ if (zbookmark_subtree_completed(dnp, zb, last_zb))
+ return (B_TRUE);
+
+ return (B_FALSE);
+}
+
+static void
+dsl_scan_prefetch(scan_prefetch_ctx_t *spc, blkptr_t *bp, zbookmark_phys_t *zb)
+{
+ avl_index_t idx;
+ dsl_scan_t *scn = spc->spc_scn;
+ spa_t *spa = scn->scn_dp->dp_spa;
+ scan_prefetch_issue_ctx_t *spic;
+
+ if (zfs_no_scrub_prefetch)
+ return;
+
+ if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg ||
+ (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE &&
+ BP_GET_TYPE(bp) != DMU_OT_OBJSET))
+ return;
+
+ if (dsl_scan_check_prefetch_resume(spc, zb))
+ return;
+
+ scan_prefetch_ctx_add_ref(spc, scn);
+ spic = kmem_alloc(sizeof (scan_prefetch_issue_ctx_t), KM_SLEEP);
+ spic->spic_spc = spc;
+ spic->spic_bp = *bp;
+ spic->spic_zb = *zb;
+
+ /*
+ * Add the IO to the queue of blocks to prefetch. This allows us to
+ * prioritize blocks that we will need first for the main traversal
+ * thread.
+ */
+ mutex_enter(&spa->spa_scrub_lock);
+ if (avl_find(&scn->scn_prefetch_queue, spic, &idx) != NULL) {
+ /* this block is already queued for prefetch */
+ kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
+ scan_prefetch_ctx_rele(spc, scn);
+ mutex_exit(&spa->spa_scrub_lock);
+ return;
+ }
+
+ avl_insert(&scn->scn_prefetch_queue, spic, idx);
+ cv_broadcast(&spa->spa_scrub_io_cv);
+ mutex_exit(&spa->spa_scrub_lock);
+}
+
+static void
+dsl_scan_prefetch_dnode(dsl_scan_t *scn, dnode_phys_t *dnp,
+ uint64_t objset, uint64_t object)
+{
+ int i;
+ zbookmark_phys_t zb;
+ scan_prefetch_ctx_t *spc;
+
+ if (dnp->dn_nblkptr == 0 && !(dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
+ return;
+
+ SET_BOOKMARK(&zb, objset, object, 0, 0);
+
+ spc = scan_prefetch_ctx_create(scn, dnp, FTAG);
+
+ for (i = 0; i < dnp->dn_nblkptr; i++) {
+ zb.zb_level = BP_GET_LEVEL(&dnp->dn_blkptr[i]);
+ zb.zb_blkid = i;
+ dsl_scan_prefetch(spc, &dnp->dn_blkptr[i], &zb);
+ }
+
+ if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
+ zb.zb_level = 0;
+ zb.zb_blkid = DMU_SPILL_BLKID;
+ dsl_scan_prefetch(spc, DN_SPILL_BLKPTR(dnp), &zb);
+ }
+
+ scan_prefetch_ctx_rele(spc, FTAG);
+}
+
+void
+dsl_scan_prefetch_cb(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
+ arc_buf_t *buf, void *private)
+{
+ scan_prefetch_ctx_t *spc = private;
+ dsl_scan_t *scn = spc->spc_scn;
+ spa_t *spa = scn->scn_dp->dp_spa;
+
+ /* broadcast that the IO has completed for rate limitting purposes */
+ mutex_enter(&spa->spa_scrub_lock);
+ ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
+ spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
+ cv_broadcast(&spa->spa_scrub_io_cv);
+ mutex_exit(&spa->spa_scrub_lock);
+
+ /* if there was an error or we are done prefetching, just cleanup */
+ if (buf == NULL || scn->scn_suspending)
+ goto out;
+
+ if (BP_GET_LEVEL(bp) > 0) {
+ int i;
+ blkptr_t *cbp;
+ int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
+ zbookmark_phys_t czb;
+
+ for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
+ SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
+ zb->zb_level - 1, zb->zb_blkid * epb + i);
+ dsl_scan_prefetch(spc, cbp, &czb);
+ }
+ } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
+ dnode_phys_t *cdnp;
+ int i;
+ int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
+
+ for (i = 0, cdnp = buf->b_data; i < epb;
+ i += cdnp->dn_extra_slots + 1,
+ cdnp += cdnp->dn_extra_slots + 1) {
+ dsl_scan_prefetch_dnode(scn, cdnp,
+ zb->zb_objset, zb->zb_blkid * epb + i);
+ }
+ } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
+ objset_phys_t *osp = buf->b_data;
+
+ dsl_scan_prefetch_dnode(scn, &osp->os_meta_dnode,
+ zb->zb_objset, DMU_META_DNODE_OBJECT);
+
+ if (OBJSET_BUF_HAS_USERUSED(buf)) {
+ dsl_scan_prefetch_dnode(scn,
+ &osp->os_groupused_dnode, zb->zb_objset,
+ DMU_GROUPUSED_OBJECT);
+ dsl_scan_prefetch_dnode(scn,
+ &osp->os_userused_dnode, zb->zb_objset,
+ DMU_USERUSED_OBJECT);
+ }
+ }
+
+out:
+ if (buf != NULL)
+ arc_buf_destroy(buf, private);
+ scan_prefetch_ctx_rele(spc, scn);
+}
+
+/* ARGSUSED */
+static void
+dsl_scan_prefetch_thread(void *arg)
+{
+ dsl_scan_t *scn = arg;
+ spa_t *spa = scn->scn_dp->dp_spa;
+ scan_prefetch_issue_ctx_t *spic;
+
+ /* loop until we are told to stop */
+ while (!scn->scn_prefetch_stop) {
+ arc_flags_t flags = ARC_FLAG_NOWAIT |
+ ARC_FLAG_PRESCIENT_PREFETCH | ARC_FLAG_PREFETCH;
+ int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
+
+ mutex_enter(&spa->spa_scrub_lock);
+
+ /*
+ * Wait until we have an IO to issue and are not above our
+ * maximum in flight limit.
+ */
+ while (!scn->scn_prefetch_stop &&
+ (avl_numnodes(&scn->scn_prefetch_queue) == 0 ||
+ spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)) {
+ cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
+ }
+
+ /* recheck if we should stop since we waited for the cv */
+ if (scn->scn_prefetch_stop) {
+ mutex_exit(&spa->spa_scrub_lock);
+ break;
+ }
+
+ /* remove the prefetch IO from the tree */
+ spic = avl_first(&scn->scn_prefetch_queue);
+ spa->spa_scrub_inflight += BP_GET_PSIZE(&spic->spic_bp);
+ avl_remove(&scn->scn_prefetch_queue, spic);
+
+ mutex_exit(&spa->spa_scrub_lock);
+
+ if (BP_IS_PROTECTED(&spic->spic_bp)) {
+ ASSERT(BP_GET_TYPE(&spic->spic_bp) == DMU_OT_DNODE ||
+ BP_GET_TYPE(&spic->spic_bp) == DMU_OT_OBJSET);
+ ASSERT3U(BP_GET_LEVEL(&spic->spic_bp), ==, 0);
+ zio_flags |= ZIO_FLAG_RAW;
+ }
+
+ /* issue the prefetch asynchronously */
+ (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa,
+ &spic->spic_bp, dsl_scan_prefetch_cb, spic->spic_spc,
+ ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, &spic->spic_zb);
- if (BP_IS_PROTECTED(bp)) {
- ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_DNODE);
- ASSERT3U(BP_GET_LEVEL(bp), ==, 0);
- zio_flags |= ZIO_FLAG_RAW;
+ kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
}
- SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
+ ASSERT(scn->scn_prefetch_stop);
- (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
- NULL, NULL, ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, &czb);
+ /* free any prefetches we didn't get to complete */
+ mutex_enter(&spa->spa_scrub_lock);
+ while ((spic = avl_first(&scn->scn_prefetch_queue)) != NULL) {
+ avl_remove(&scn->scn_prefetch_queue, spic);
+ scan_prefetch_ctx_rele(spic->spic_spc, scn);
+ kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
+ }
+ ASSERT0(avl_numnodes(&scn->scn_prefetch_queue));
+ mutex_exit(&spa->spa_scrub_lock);
}
static boolean_t
return (B_FALSE);
}
+static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
+ dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
+ dmu_objset_type_t ostype, dmu_tx_t *tx);
+inline __attribute__((always_inline)) static void dsl_scan_visitdnode(
+ dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype,
+ dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
+
/*
* Return nonzero on i/o error.
* Return new buf to write out in *bufp.
scn->scn_phys.scn_errors++;
return (err);
}
- for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
- dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
- zb->zb_object, zb->zb_blkid * epb + i);
- }
for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
zbookmark_phys_t czb;
} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
arc_flags_t flags = ARC_FLAG_WAIT;
dnode_phys_t *cdnp;
- int i, j;
+ int i;
int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
arc_buf_t *buf;
scn->scn_phys.scn_errors++;
return (err);
}
- for (i = 0, cdnp = buf->b_data; i < epb;
- i += cdnp->dn_extra_slots + 1,
- cdnp += cdnp->dn_extra_slots + 1) {
- for (j = 0; j < cdnp->dn_nblkptr; j++) {
- blkptr_t *cbp = &cdnp->dn_blkptr[j];
- dsl_scan_prefetch(scn, buf, cbp,
- zb->zb_objset, zb->zb_blkid * epb + i, j);
- }
- }
for (i = 0, cdnp = buf->b_data; i < epb;
i += cdnp->dn_extra_slots + 1,
cdnp += cdnp->dn_extra_slots + 1) {
/*
* We also always visit user/group accounting
* objects, and never skip them, even if we are
- * suspending. This is necessary so that the space
- * deltas from this txg get integrated.
+ * suspending. This is necessary so that the
+ * space deltas from this txg get integrated.
*/
dsl_scan_visitdnode(scn, ds, osp->os_type,
&osp->os_groupused_dnode,
dmu_objset_type_t ostype, dmu_tx_t *tx)
{
dsl_pool_t *dp = scn->scn_dp;
- blkptr_t *bp_toread;
-
- bp_toread = kmem_alloc(sizeof (blkptr_t), KM_SLEEP);
- *bp_toread = *bp;
-
- /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
+ blkptr_t *bp_toread = NULL;
if (dsl_scan_check_suspend(scn, zb))
- goto out;
+ return;
if (dsl_scan_check_resume(scn, dnp, zb))
- goto out;
-
- if (BP_IS_HOLE(bp))
- goto out;
+ return;
scn->scn_visited_this_txg++;
* if required to debug an issue in dsl_scan_visitbp().
*
* dprintf_bp(bp,
- * "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
- * ds, ds ? ds->ds_object : 0,
- * zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
- * bp);
+ * "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
+ * ds, ds ? ds->ds_object : 0,
+ * zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
+ * bp);
*/
- if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
- goto out;
+ if (BP_IS_HOLE(bp)) {
+ scn->scn_holes_this_txg++;
+ return;
+ }
+
+ if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) {
+ scn->scn_lt_min_this_txg++;
+ return;
+ }
+
+ bp_toread = kmem_alloc(sizeof (blkptr_t), KM_SLEEP);
+ *bp_toread = *bp;
if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx) != 0)
goto out;
*/
if (ddt_class_contains(dp->dp_spa,
scn->scn_phys.scn_ddt_class_max, bp)) {
+ scn->scn_ddt_contained_this_txg++;
goto out;
}
* Don't scan it now unless we need to because something
* under it was modified.
*/
- if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
- scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
+ if (BP_PHYSICAL_BIRTH(bp) > scn->scn_phys.scn_cur_max_txg) {
+ scn->scn_gt_max_this_txg++;
+ goto out;
}
+
+ scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
+
out:
kmem_free(bp_toread, sizeof (blkptr_t));
}
dmu_tx_t *tx)
{
zbookmark_phys_t zb;
+ scan_prefetch_ctx_t *spc;
SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
- dsl_scan_visitbp(bp, &zb, NULL,
- ds, scn, DMU_OST_NONE, tx);
+
+ if (ZB_IS_ZERO(&scn->scn_phys.scn_bookmark)) {
+ SET_BOOKMARK(&scn->scn_prefetch_bookmark,
+ zb.zb_objset, 0, 0, 0);
+ } else {
+ scn->scn_prefetch_bookmark = scn->scn_phys.scn_bookmark;
+ }
+
+ scn->scn_objsets_visited_this_txg++;
+
+ spc = scan_prefetch_ctx_create(scn, NULL, FTAG);
+ dsl_scan_prefetch(spc, bp, &zb);
+ scan_prefetch_ctx_rele(spc, FTAG);
+
+ dsl_scan_visitbp(bp, &zb, NULL, ds, scn, DMU_OST_NONE, tx);
dprintf_ds(ds, "finished scan%s", "");
}
-void
-dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
+static void
+ds_destroyed_scn_phys(dsl_dataset_t *ds, dsl_scan_phys_t *scn_phys)
{
- dsl_pool_t *dp = ds->ds_dir->dd_pool;
- dsl_scan_t *scn = dp->dp_scan;
- uint64_t mintxg;
-
- if (scn->scn_phys.scn_state != DSS_SCANNING)
- return;
-
- if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
+ if (scn_phys->scn_bookmark.zb_objset == ds->ds_object) {
if (ds->ds_is_snapshot) {
/*
* Note:
* ignore it when we retraverse it in
* dsl_scan_visitds().
*/
- scn->scn_phys.scn_bookmark.zb_objset =
+ scn_phys->scn_bookmark.zb_objset =
dsl_dataset_phys(ds)->ds_next_snap_obj;
zfs_dbgmsg("destroying ds %llu; currently traversing; "
"reset zb_objset to %llu",
(u_longlong_t)ds->ds_object,
(u_longlong_t)dsl_dataset_phys(ds)->
ds_next_snap_obj);
- scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
+ scn_phys->scn_flags |= DSF_VISIT_DS_AGAIN;
} else {
- SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
+ SET_BOOKMARK(&scn_phys->scn_bookmark,
ZB_DESTROYED_OBJSET, 0, 0, 0);
zfs_dbgmsg("destroying ds %llu; currently traversing; "
"reset bookmark to -1,0,0,0",
(u_longlong_t)ds->ds_object);
}
- } else if (zap_lookup_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
+ }
+}
+
+/*
+ * Invoked when a dataset is destroyed. We need to make sure that:
+ *
+ * 1) If it is the dataset that was currently being scanned, we write
+ * a new dsl_scan_phys_t and marking the objset reference in it
+ * as destroyed.
+ * 2) Remove it from the work queue, if it was present.
+ *
+ * If the dataset was actually a snapshot, instead of marking the dataset
+ * as destroyed, we instead substitute the next snapshot in line.
+ */
+void
+dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
+{
+ dsl_pool_t *dp = ds->ds_dir->dd_pool;
+ dsl_scan_t *scn = dp->dp_scan;
+ uint64_t mintxg;
+
+ if (!dsl_scan_is_running(scn))
+ return;
+
+ ds_destroyed_scn_phys(ds, &scn->scn_phys);
+ ds_destroyed_scn_phys(ds, &scn->scn_phys_cached);
+
+ if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
+ scan_ds_queue_remove(scn, ds->ds_object);
+ if (ds->ds_is_snapshot)
+ scan_ds_queue_insert(scn,
+ dsl_dataset_phys(ds)->ds_next_snap_obj, mintxg);
+ }
+
+ if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
+ ds->ds_object, &mintxg) == 0) {
ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
* dsl_scan_sync() should be called after this, and should sync
* out our changed state, but just to be safe, do it here.
*/
- dsl_scan_sync_state(scn, tx);
+ dsl_scan_sync_state(scn, tx, SYNC_CACHED);
+}
+
+static void
+ds_snapshotted_bookmark(dsl_dataset_t *ds, zbookmark_phys_t *scn_bookmark)
+{
+ if (scn_bookmark->zb_objset == ds->ds_object) {
+ scn_bookmark->zb_objset =
+ dsl_dataset_phys(ds)->ds_prev_snap_obj;
+ zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
+ "reset zb_objset to %llu",
+ (u_longlong_t)ds->ds_object,
+ (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
+ }
}
+/*
+ * Called when a dataset is snapshotted. If we were currently traversing
+ * this snapshot, we reset our bookmark to point at the newly created
+ * snapshot. We also modify our work queue to remove the old snapshot and
+ * replace with the new one.
+ */
void
dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
{
dsl_scan_t *scn = dp->dp_scan;
uint64_t mintxg;
- if (scn->scn_phys.scn_state != DSS_SCANNING)
+ if (!dsl_scan_is_running(scn))
return;
ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
- if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
- scn->scn_phys.scn_bookmark.zb_objset =
- dsl_dataset_phys(ds)->ds_prev_snap_obj;
- zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
- "reset zb_objset to %llu",
- (u_longlong_t)ds->ds_object,
- (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
- } else if (zap_lookup_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
+ ds_snapshotted_bookmark(ds, &scn->scn_phys.scn_bookmark);
+ ds_snapshotted_bookmark(ds, &scn->scn_phys_cached.scn_bookmark);
+
+ if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
+ scan_ds_queue_remove(scn, ds->ds_object);
+ scan_ds_queue_insert(scn,
+ dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg);
+ }
+
+ if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
+ ds->ds_object, &mintxg) == 0) {
VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
VERIFY(zap_add_int_key(dp->dp_meta_objset,
(u_longlong_t)ds->ds_object,
(u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
}
- dsl_scan_sync_state(scn, tx);
+
+ dsl_scan_sync_state(scn, tx, SYNC_CACHED);
}
-void
-dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
+static void
+ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_dataset_t *ds2,
+ zbookmark_phys_t *scn_bookmark)
{
- dsl_pool_t *dp = ds1->ds_dir->dd_pool;
- dsl_scan_t *scn = dp->dp_scan;
- uint64_t mintxg;
-
- if (scn->scn_phys.scn_state != DSS_SCANNING)
- return;
-
- if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
- scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
+ if (scn_bookmark->zb_objset == ds1->ds_object) {
+ scn_bookmark->zb_objset = ds2->ds_object;
zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
"reset zb_objset to %llu",
(u_longlong_t)ds1->ds_object,
(u_longlong_t)ds2->ds_object);
- } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
- scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
+ } else if (scn_bookmark->zb_objset == ds2->ds_object) {
+ scn_bookmark->zb_objset = ds1->ds_object;
zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
"reset zb_objset to %llu",
(u_longlong_t)ds2->ds_object,
(u_longlong_t)ds1->ds_object);
}
+}
+
+/*
+ * Called when a parent dataset and its clone are swapped. If we were
+ * currently traversing the dataset, we need to switch to traversing the
+ * newly promoted parent.
+ */
+void
+dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
+{
+ dsl_pool_t *dp = ds1->ds_dir->dd_pool;
+ dsl_scan_t *scn = dp->dp_scan;
+ uint64_t mintxg;
+
+ if (!dsl_scan_is_running(scn))
+ return;
+
+ ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
+ ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
+
+ if (scan_ds_queue_contains(scn, ds1->ds_object, &mintxg)) {
+ scan_ds_queue_remove(scn, ds1->ds_object);
+ scan_ds_queue_insert(scn, ds2->ds_object, mintxg);
+ }
+ if (scan_ds_queue_contains(scn, ds2->ds_object, &mintxg)) {
+ scan_ds_queue_remove(scn, ds2->ds_object);
+ scan_ds_queue_insert(scn, ds1->ds_object, mintxg);
+ }
if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
ds1->ds_object, &mintxg) == 0) {
int err;
-
ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
"replacing with %llu",
(u_longlong_t)ds1->ds_object,
(u_longlong_t)ds2->ds_object);
- } else if (zap_lookup_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
+ }
+ if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
+ ds2->ds_object, &mintxg) == 0) {
ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
(u_longlong_t)ds1->ds_object);
}
- dsl_scan_sync_state(scn, tx);
+ dsl_scan_sync_state(scn, tx, SYNC_CACHED);
}
-struct enqueue_clones_arg {
- dmu_tx_t *tx;
- uint64_t originobj;
-};
-
/* ARGSUSED */
static int
enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
{
- struct enqueue_clones_arg *eca = arg;
+ uint64_t originobj = *(uint64_t *)arg;
dsl_dataset_t *ds;
int err;
dsl_scan_t *scn = dp->dp_scan;
- if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != eca->originobj)
+ if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != originobj)
return (0);
err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
if (err)
return (err);
- while (dsl_dataset_phys(ds)->ds_prev_snap_obj != eca->originobj) {
+ while (dsl_dataset_phys(ds)->ds_prev_snap_obj != originobj) {
dsl_dataset_t *prev;
err = dsl_dataset_hold_obj(dp,
dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
return (err);
ds = prev;
}
- VERIFY(zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds->ds_object,
- dsl_dataset_phys(ds)->ds_prev_snap_txg, eca->tx) == 0);
+ scan_ds_queue_insert(scn, ds->ds_object,
+ dsl_dataset_phys(ds)->ds_prev_snap_txg);
dsl_dataset_rele(ds, FTAG);
return (0);
}
dsl_dataset_name(ds, dsname);
zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because "
"cur_min_txg (%llu) >= max_txg (%llu)",
- dsobj, dsname,
- scn->scn_phys.scn_cur_min_txg,
- scn->scn_phys.scn_max_txg);
+ (longlong_t)dsobj, dsname,
+ (longlong_t)scn->scn_phys.scn_cur_min_txg,
+ (longlong_t)scn->scn_phys.scn_max_txg);
kmem_free(dsname, MAXNAMELEN);
goto out;
* 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) && !ds->ds_is_snapshot)
+ if (!ds->ds_is_snapshot)
dsl_scan_zil(dp, &os->os_zil_header);
/*
if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
zfs_dbgmsg("incomplete pass; visiting again");
scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
- VERIFY(zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, ds->ds_object,
- scn->scn_phys.scn_cur_max_txg, tx) == 0);
+ scan_ds_queue_insert(scn, ds->ds_object,
+ scn->scn_phys.scn_cur_max_txg);
goto out;
}
* Add descendent datasets to work queue.
*/
if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
- VERIFY(zap_add_int_key(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj,
+ scan_ds_queue_insert(scn,
dsl_dataset_phys(ds)->ds_next_snap_obj,
- dsl_dataset_phys(ds)->ds_creation_txg, tx) == 0);
+ dsl_dataset_phys(ds)->ds_creation_txg);
}
if (dsl_dataset_phys(ds)->ds_num_children > 1) {
boolean_t usenext = B_FALSE;
}
if (usenext) {
- VERIFY0(zap_join_key(dp->dp_meta_objset,
- dsl_dataset_phys(ds)->ds_next_clones_obj,
- scn->scn_phys.scn_queue_obj,
- dsl_dataset_phys(ds)->ds_creation_txg, tx));
+ zap_cursor_t zc;
+ zap_attribute_t za;
+ for (zap_cursor_init(&zc, dp->dp_meta_objset,
+ dsl_dataset_phys(ds)->ds_next_clones_obj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ (void) zap_cursor_advance(&zc)) {
+ scan_ds_queue_insert(scn,
+ zfs_strtonum(za.za_name, NULL),
+ dsl_dataset_phys(ds)->ds_creation_txg);
+ }
+ zap_cursor_fini(&zc);
} else {
- struct enqueue_clones_arg eca;
- eca.tx = tx;
- eca.originobj = ds->ds_object;
-
VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
- enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
+ enqueue_clones_cb, &ds->ds_object,
+ DS_FIND_CHILDREN));
}
}
static int
enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
{
- dmu_tx_t *tx = arg;
dsl_dataset_t *ds;
int err;
dsl_scan_t *scn = dp->dp_scan;
ds = prev;
}
- VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
- ds->ds_object, dsl_dataset_phys(ds)->ds_prev_snap_txg, tx) == 0);
+ scan_ds_queue_insert(scn, ds->ds_object,
+ dsl_dataset_phys(ds)->ds_prev_snap_txg);
dsl_dataset_rele(ds, FTAG);
return (0);
}
+/* ARGSUSED */
+void
+dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
+ ddt_entry_t *dde, dmu_tx_t *tx)
+{
+ const ddt_key_t *ddk = &dde->dde_key;
+ ddt_phys_t *ddp = dde->dde_phys;
+ blkptr_t bp;
+ zbookmark_phys_t zb = { 0 };
+ int p;
+
+ if (scn->scn_phys.scn_state != DSS_SCANNING)
+ return;
+
+ for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+ if (ddp->ddp_phys_birth == 0 ||
+ ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
+ continue;
+ ddt_bp_create(checksum, ddk, ddp, &bp);
+
+ scn->scn_visited_this_txg++;
+ scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
+ }
+}
+
/*
* Scrub/dedup interaction.
*
ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
}
-/* ARGSUSED */
-void
-dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
- ddt_entry_t *dde, dmu_tx_t *tx)
+static uint64_t
+dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
{
- const ddt_key_t *ddk = &dde->dde_key;
- ddt_phys_t *ddp = dde->dde_phys;
- blkptr_t bp;
- zbookmark_phys_t zb = { 0 };
-
- if (scn->scn_phys.scn_state != DSS_SCANNING)
- return;
-
- for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
- if (ddp->ddp_phys_birth == 0 ||
- ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
- continue;
- ddt_bp_create(checksum, ddk, ddp, &bp);
-
- scn->scn_visited_this_txg++;
- scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
- }
+ uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
+ if (ds->ds_is_snapshot)
+ return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
+ return (smt);
}
static void
dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
{
+ scan_ds_t *sds;
dsl_pool_t *dp = scn->scn_dp;
- zap_cursor_t *zc;
- zap_attribute_t *za;
if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
scn->scn_phys.scn_ddt_class_max) {
if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
- enqueue_cb, tx, DS_FIND_CHILDREN));
+ enqueue_cb, NULL, DS_FIND_CHILDREN));
} else {
dsl_scan_visitds(scn,
dp->dp_origin_snap->ds_object, tx);
ASSERT(!scn->scn_suspending);
} else if (scn->scn_phys.scn_bookmark.zb_objset !=
ZB_DESTROYED_OBJSET) {
+ uint64_t dsobj = scn->scn_phys.scn_bookmark.zb_objset;
/*
- * If we were suspended, continue from here. Note if the
+ * If we were suspended, continue from here. Note if the
* ds we were suspended on was deleted, the zb_objset may
* be -1, so we will skip this and find a new objset
* below.
*/
- dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
+ dsl_scan_visitds(scn, dsobj, tx);
if (scn->scn_suspending)
return;
}
/*
- * In case we were suspended right at the end of the ds, zero the
+ * In case we suspended right at the end of the ds, zero the
* bookmark so we don't think that we're still trying to resume.
*/
bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
- zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP);
- za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
- /* keep pulling things out of the zap-object-as-queue */
- while (zap_cursor_init(zc, dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj),
- zap_cursor_retrieve(zc, za) == 0) {
+ /*
+ * Keep pulling things out of the dataset avl queue. Updates to the
+ * persistent zap-object-as-queue happen only at checkpoints.
+ */
+ while ((sds = avl_first(&scn->scn_queue)) != NULL) {
dsl_dataset_t *ds;
- uint64_t dsobj;
+ uint64_t dsobj = sds->sds_dsobj;
+ uint64_t txg = sds->sds_txg;
- dsobj = zfs_strtonum(za->za_name, NULL);
- VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
- scn->scn_phys.scn_queue_obj, dsobj, tx));
+ /* dequeue and free the ds from the queue */
+ scan_ds_queue_remove(scn, dsobj);
+ sds = NULL;
- /* Set up min/max txg */
+ /* set up min / max txg */
VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
- if (za->za_first_integer != 0) {
+ if (txg != 0) {
scn->scn_phys.scn_cur_min_txg =
- MAX(scn->scn_phys.scn_min_txg,
- za->za_first_integer);
+ MAX(scn->scn_phys.scn_min_txg, txg);
} else {
scn->scn_phys.scn_cur_min_txg =
MAX(scn->scn_phys.scn_min_txg,
dsl_dataset_rele(ds, FTAG);
dsl_scan_visitds(scn, dsobj, tx);
- zap_cursor_fini(zc);
if (scn->scn_suspending)
- goto out;
+ return;
}
- zap_cursor_fini(zc);
-out:
- kmem_free(za, sizeof (zap_attribute_t));
- kmem_free(zc, sizeof (zap_cursor_t));
+
+ /* No more objsets to fetch, we're done */
+ scn->scn_phys.scn_bookmark.zb_objset = ZB_DESTROYED_OBJSET;
+ ASSERT0(scn->scn_suspending);
+}
+
+static uint64_t
+dsl_scan_count_leaves(vdev_t *vd)
+{
+ uint64_t i, leaves = 0;
+
+ /* we only count leaves that belong to the main pool and are readable */
+ if (vd->vdev_islog || vd->vdev_isspare ||
+ vd->vdev_isl2cache || !vdev_readable(vd))
+ return (0);
+
+ if (vd->vdev_ops->vdev_op_leaf)
+ return (1);
+
+ for (i = 0; i < vd->vdev_children; i++) {
+ leaves += dsl_scan_count_leaves(vd->vdev_child[i]);
+ }
+
+ return (leaves);
+}
+
+static void
+scan_io_queues_update_zio_stats(dsl_scan_io_queue_t *q, const blkptr_t *bp)
+{
+ int i;
+ uint64_t cur_size = 0;
+
+ for (i = 0; i < BP_GET_NDVAS(bp); i++) {
+ cur_size += DVA_GET_ASIZE(&bp->blk_dva[i]);
+ }
+
+ q->q_total_zio_size_this_txg += cur_size;
+ q->q_zios_this_txg++;
+}
+
+static void
+scan_io_queues_update_seg_stats(dsl_scan_io_queue_t *q, uint64_t start,
+ uint64_t end)
+{
+ q->q_total_seg_size_this_txg += end - start;
+ q->q_segs_this_txg++;
+}
+
+static boolean_t
+scan_io_queue_check_suspend(dsl_scan_t *scn)
+{
+ /* See comment in dsl_scan_check_suspend() */
+ uint64_t curr_time_ns = gethrtime();
+ uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
+ uint64_t sync_time_ns = curr_time_ns -
+ scn->scn_dp->dp_spa->spa_sync_starttime;
+ int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
+ int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
+ zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
+
+ return ((NSEC2MSEC(scan_time_ns) > mintime &&
+ (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
+ txg_sync_waiting(scn->scn_dp) ||
+ NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
+ spa_shutting_down(scn->scn_dp->dp_spa));
+}
+
+/*
+ * Given a list of scan_io_t's in io_list, this issues the io's out to
+ * disk. This consumes the io_list and frees the scan_io_t's. This is
+ * called when emptying queues, either when we're up against the memory
+ * limit or when we have finished scanning. Returns B_TRUE if we stopped
+ * processing the list before we finished. Any zios that were not issued
+ * will remain in the io_list.
+ */
+static boolean_t
+scan_io_queue_issue(dsl_scan_io_queue_t *queue, list_t *io_list)
+{
+ dsl_scan_t *scn = queue->q_scn;
+ scan_io_t *sio;
+ int64_t bytes_issued = 0;
+ boolean_t suspended = B_FALSE;
+
+ while ((sio = list_head(io_list)) != NULL) {
+ blkptr_t bp;
+
+ if (scan_io_queue_check_suspend(scn)) {
+ suspended = B_TRUE;
+ break;
+ }
+
+ sio2bp(sio, &bp, queue->q_vd->vdev_id);
+ bytes_issued += sio->sio_asize;
+ scan_exec_io(scn->scn_dp, &bp, sio->sio_flags,
+ &sio->sio_zb, queue);
+ (void) list_remove_head(io_list);
+ scan_io_queues_update_zio_stats(queue, &bp);
+ kmem_cache_free(sio_cache, sio);
+ }
+
+ atomic_add_64(&scn->scn_bytes_pending, -bytes_issued);
+
+ return (suspended);
+}
+
+/*
+ * This function removes sios from an IO queue which reside within a given
+ * range_seg_t and inserts them (in offset order) into a list. Note that
+ * we only ever return a maximum of 32 sios at once. If there are more sios
+ * to process within this segment that did not make it onto the list we
+ * return B_TRUE and otherwise B_FALSE.
+ */
+static boolean_t
+scan_io_queue_gather(dsl_scan_io_queue_t *queue, range_seg_t *rs, list_t *list)
+{
+ scan_io_t srch_sio, *sio, *next_sio;
+ avl_index_t idx;
+ uint_t num_sios = 0;
+ int64_t bytes_issued = 0;
+
+ ASSERT(rs != NULL);
+ ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
+
+ srch_sio.sio_offset = rs->rs_start;
+
+ /*
+ * The exact start of the extent might not contain any matching zios,
+ * so if that's the case, examine the next one in the tree.
+ */
+ sio = avl_find(&queue->q_sios_by_addr, &srch_sio, &idx);
+ if (sio == NULL)
+ sio = avl_nearest(&queue->q_sios_by_addr, idx, AVL_AFTER);
+
+ while (sio != NULL && sio->sio_offset < rs->rs_end && num_sios <= 32) {
+ ASSERT3U(sio->sio_offset, >=, rs->rs_start);
+ ASSERT3U(sio->sio_offset + sio->sio_asize, <=, rs->rs_end);
+
+ next_sio = AVL_NEXT(&queue->q_sios_by_addr, sio);
+ avl_remove(&queue->q_sios_by_addr, sio);
+
+ bytes_issued += sio->sio_asize;
+ num_sios++;
+ list_insert_tail(list, sio);
+ sio = next_sio;
+ }
+
+ /*
+ * We limit the number of sios we process at once to 32 to avoid
+ * biting off more than we can chew. If we didn't take everything
+ * in the segment we update it to reflect the work we were able to
+ * complete. Otherwise, we remove it from the range tree entirely.
+ */
+ if (sio != NULL && sio->sio_offset < rs->rs_end) {
+ range_tree_adjust_fill(queue->q_exts_by_addr, rs,
+ -bytes_issued);
+ range_tree_resize_segment(queue->q_exts_by_addr, rs,
+ sio->sio_offset, rs->rs_end - sio->sio_offset);
+
+ return (B_TRUE);
+ } else {
+ range_tree_remove(queue->q_exts_by_addr, rs->rs_start,
+ rs->rs_end - rs->rs_start);
+ return (B_FALSE);
+ }
+}
+
+/*
+ * This is called from the queue emptying thread and selects the next
+ * extent from which we are to issue io's. The behavior of this function
+ * depends on the state of the scan, the current memory consumption and
+ * whether or not we are performing a scan shutdown.
+ * 1) We select extents in an elevator algorithm (LBA-order) if the scan
+ * needs to perform a checkpoint
+ * 2) We select the largest available extent if we are up against the
+ * memory limit.
+ * 3) Otherwise we don't select any extents.
+ */
+static range_seg_t *
+scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
+{
+ dsl_scan_t *scn = queue->q_scn;
+
+ ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
+ ASSERT(scn->scn_is_sorted);
+
+ /* handle tunable overrides */
+ if (scn->scn_checkpointing || scn->scn_clearing) {
+ if (zfs_scan_issue_strategy == 1) {
+ return (range_tree_first(queue->q_exts_by_addr));
+ } else if (zfs_scan_issue_strategy == 2) {
+ return (avl_first(&queue->q_exts_by_size));
+ }
+ }
+
+ /*
+ * During normal clearing, we want to issue our largest segments
+ * first, keeping IO as sequential as possible, and leaving the
+ * smaller extents for later with the hope that they might eventually
+ * grow to larger sequential segments. However, when the scan is
+ * checkpointing, no new extents will be added to the sorting queue,
+ * so the way we are sorted now is as good as it will ever get.
+ * In this case, we instead switch to issuing extents in LBA order.
+ */
+ if (scn->scn_checkpointing) {
+ return (range_tree_first(queue->q_exts_by_addr));
+ } else if (scn->scn_clearing) {
+ return (avl_first(&queue->q_exts_by_size));
+ } else {
+ return (NULL);
+ }
+}
+
+static void
+scan_io_queues_run_one(void *arg)
+{
+ dsl_scan_io_queue_t *queue = arg;
+ kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
+ boolean_t suspended = B_FALSE;
+ range_seg_t *rs = NULL;
+ scan_io_t *sio = NULL;
+ list_t sio_list;
+ uint64_t bytes_per_leaf = zfs_scan_vdev_limit;
+ uint64_t nr_leaves = dsl_scan_count_leaves(queue->q_vd);
+
+ ASSERT(queue->q_scn->scn_is_sorted);
+
+ list_create(&sio_list, sizeof (scan_io_t),
+ offsetof(scan_io_t, sio_nodes.sio_list_node));
+ mutex_enter(q_lock);
+
+ /* calculate maximum in-flight bytes for this txg (min 1MB) */
+ queue->q_maxinflight_bytes =
+ MAX(nr_leaves * bytes_per_leaf, 1ULL << 20);
+
+ /* reset per-queue scan statistics for this txg */
+ queue->q_total_seg_size_this_txg = 0;
+ queue->q_segs_this_txg = 0;
+ queue->q_total_zio_size_this_txg = 0;
+ queue->q_zios_this_txg = 0;
+
+ /* loop until we run out of time or sios */
+ while ((rs = scan_io_queue_fetch_ext(queue)) != NULL) {
+ uint64_t seg_start = 0, seg_end = 0;
+ boolean_t more_left = B_TRUE;
+
+ ASSERT(list_is_empty(&sio_list));
+
+ /* loop while we still have sios left to process in this rs */
+ while (more_left) {
+ scan_io_t *first_sio, *last_sio;
+
+ /*
+ * We have selected which extent needs to be
+ * processed next. Gather up the corresponding sios.
+ */
+ more_left = scan_io_queue_gather(queue, rs, &sio_list);
+ ASSERT(!list_is_empty(&sio_list));
+ first_sio = list_head(&sio_list);
+ last_sio = list_tail(&sio_list);
+
+ seg_end = last_sio->sio_offset + last_sio->sio_asize;
+ if (seg_start == 0)
+ seg_start = first_sio->sio_offset;
+
+ /*
+ * Issuing sios can take a long time so drop the
+ * queue lock. The sio queue won't be updated by
+ * other threads since we're in syncing context so
+ * we can be sure that our trees will remain exactly
+ * as we left them.
+ */
+ mutex_exit(q_lock);
+ suspended = scan_io_queue_issue(queue, &sio_list);
+ mutex_enter(q_lock);
+
+ if (suspended)
+ break;
+ }
+
+ /* update statistics for debugging purposes */
+ scan_io_queues_update_seg_stats(queue, seg_start, seg_end);
+
+ if (suspended)
+ break;
+ }
+
+ /*
+ * If we were suspended in the middle of processing,
+ * requeue any unfinished sios and exit.
+ */
+ while ((sio = list_head(&sio_list)) != NULL) {
+ list_remove(&sio_list, sio);
+ scan_io_queue_insert_impl(queue, sio);
+ }
+
+ mutex_exit(q_lock);
+ list_destroy(&sio_list);
+}
+
+/*
+ * Performs an emptying run on all scan queues in the pool. This just
+ * punches out one thread per top-level vdev, each of which processes
+ * only that vdev's scan queue. We can parallelize the I/O here because
+ * we know that each queue's io's only affect its own top-level vdev.
+ *
+ * This function waits for the queue runs to complete, and must be
+ * called from dsl_scan_sync (or in general, syncing context).
+ */
+static void
+scan_io_queues_run(dsl_scan_t *scn)
+{
+ spa_t *spa = scn->scn_dp->dp_spa;
+
+ ASSERT(scn->scn_is_sorted);
+ ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
+
+ if (scn->scn_bytes_pending == 0)
+ return;
+
+ if (scn->scn_taskq == NULL) {
+ int nthreads = spa->spa_root_vdev->vdev_children;
+
+ /*
+ * We need to make this taskq *always* execute as many
+ * threads in parallel as we have top-level vdevs and no
+ * less, otherwise strange serialization of the calls to
+ * scan_io_queues_run_one can occur during spa_sync runs
+ * and that significantly impacts performance.
+ */
+ scn->scn_taskq = taskq_create("dsl_scan_iss", nthreads,
+ minclsyspri, nthreads, nthreads, TASKQ_PREPOPULATE);
+ }
+
+ for (uint64_t i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
+ vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
+
+ mutex_enter(&vd->vdev_scan_io_queue_lock);
+ if (vd->vdev_scan_io_queue != NULL) {
+ VERIFY(taskq_dispatch(scn->scn_taskq,
+ scan_io_queues_run_one, vd->vdev_scan_io_queue,
+ TQ_SLEEP) != TASKQID_INVALID);
+ }
+ mutex_exit(&vd->vdev_scan_io_queue_lock);
+ }
+
+ /*
+ * Wait for the queues to finish issuing thir IOs for this run
+ * before we return. There may still be IOs in flight at this
+ * point.
+ */
+ taskq_wait(scn->scn_taskq);
}
static boolean_t
return (0);
}
+static void
+dsl_scan_update_stats(dsl_scan_t *scn)
+{
+ spa_t *spa = scn->scn_dp->dp_spa;
+ uint64_t i;
+ uint64_t seg_size_total = 0, zio_size_total = 0;
+ uint64_t seg_count_total = 0, zio_count_total = 0;
+
+ for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
+ vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
+ dsl_scan_io_queue_t *queue = vd->vdev_scan_io_queue;
+
+ if (queue == NULL)
+ continue;
+
+ seg_size_total += queue->q_total_seg_size_this_txg;
+ zio_size_total += queue->q_total_zio_size_this_txg;
+ seg_count_total += queue->q_segs_this_txg;
+ zio_count_total += queue->q_zios_this_txg;
+ }
+
+ if (seg_count_total == 0 || zio_count_total == 0) {
+ scn->scn_avg_seg_size_this_txg = 0;
+ scn->scn_avg_zio_size_this_txg = 0;
+ scn->scn_segs_this_txg = 0;
+ scn->scn_zios_this_txg = 0;
+ return;
+ }
+
+ scn->scn_avg_seg_size_this_txg = seg_size_total / seg_count_total;
+ scn->scn_avg_zio_size_this_txg = zio_size_total / zio_count_total;
+ scn->scn_segs_this_txg = seg_count_total;
+ scn->scn_zios_this_txg = zio_count_total;
+}
+
boolean_t
dsl_scan_active(dsl_scan_t *scn)
{
return (B_FALSE);
if (spa_shutting_down(spa))
return (B_FALSE);
- if ((scn->scn_phys.scn_state == DSS_SCANNING &&
- !dsl_scan_is_paused_scrub(scn)) ||
+ if ((dsl_scan_is_running(scn) && !dsl_scan_is_paused_scrub(scn)) ||
(scn->scn_async_destroying && !scn->scn_async_stalled))
return (B_TRUE);
return (used != 0);
}
-/* Called whenever a txg syncs. */
+static boolean_t
+dsl_scan_need_resilver(spa_t *spa, const dva_t *dva, size_t psize,
+ uint64_t phys_birth)
+{
+ vdev_t *vd;
+
+ if (DVA_GET_GANG(dva)) {
+ /*
+ * Gang members may be spread across multiple
+ * vdevs, so the best estimate we have is the
+ * scrub range, which has already been checked.
+ * XXX -- it would be better to change our
+ * allocation policy to ensure that all
+ * gang members reside on the same vdev.
+ */
+ return (B_TRUE);
+ }
+
+ vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
+
+ /*
+ * Check if the txg falls within the range which must be
+ * resilvered. DVAs outside this range can always be skipped.
+ */
+ if (!vdev_dtl_contains(vd, DTL_PARTIAL, phys_birth, 1))
+ return (B_FALSE);
+
+ /*
+ * Check if the top-level vdev must resilver this offset.
+ * When the offset does not intersect with a dirty leaf DTL
+ * then it may be possible to skip the resilver IO. The psize
+ * is provided instead of asize to simplify the check for RAIDZ.
+ */
+ if (!vdev_dtl_need_resilver(vd, DVA_GET_OFFSET(dva), psize))
+ return (B_FALSE);
+
+ return (B_TRUE);
+}
+
+/*
+ * This is the primary entry point for scans that is called from syncing
+ * context. Scans must happen entirely during syncing context so that we
+ * cna guarantee that blocks we are currently scanning will not change out
+ * from under us. While a scan is active, this funciton controls how quickly
+ * transaction groups proceed, instead of the normal handling provided by
+ * txg_sync_thread().
+ */
void
dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
{
+ int err = 0;
dsl_scan_t *scn = dp->dp_scan;
spa_t *spa = dp->dp_spa;
- int err = 0;
+ state_sync_type_t sync_type = SYNC_OPTIONAL;
/*
* Check for scn_restart_txg before checking spa_load_state, so
if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
func = POOL_SCAN_RESILVER;
zfs_dbgmsg("restarting scan func=%u txg=%llu",
- func, tx->tx_txg);
+ func, (longlong_t)tx->tx_txg);
dsl_scan_setup_sync(&func, tx);
}
/*
* Only process scans in sync pass 1.
*/
- if (spa_sync_pass(dp->dp_spa) > 1)
+ if (spa_sync_pass(spa) > 1)
return;
/*
if (!scn->scn_async_stalled && !dsl_scan_active(scn))
return;
+ /* reset scan statistics */
scn->scn_visited_this_txg = 0;
+ scn->scn_holes_this_txg = 0;
+ scn->scn_lt_min_this_txg = 0;
+ scn->scn_gt_max_this_txg = 0;
+ scn->scn_ddt_contained_this_txg = 0;
+ scn->scn_objsets_visited_this_txg = 0;
+ scn->scn_avg_seg_size_this_txg = 0;
+ scn->scn_segs_this_txg = 0;
+ scn->scn_avg_zio_size_this_txg = 0;
+ scn->scn_zios_this_txg = 0;
scn->scn_suspending = B_FALSE;
scn->scn_sync_start_time = gethrtime();
spa->spa_scrub_active = B_TRUE;
* blocks than to scrub them.
*/
if (zfs_free_bpobj_enabled &&
- spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
+ spa_version(spa) >= SPA_VERSION_DEADLISTS) {
scn->scn_is_bptree = B_FALSE;
- scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
+ scn->scn_zio_root = zio_root(spa, NULL,
NULL, ZIO_FLAG_MUSTSUCCEED);
err = bpobj_iterate(&dp->dp_free_bpobj,
dsl_scan_free_block_cb, scn, tx);
- VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
+ VERIFY0(zio_wait(scn->scn_zio_root));
+ scn->scn_zio_root = NULL;
if (err != 0 && err != ERESTART)
zfs_panic_recover("error %u from bpobj_iterate()", err);
if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
ASSERT(scn->scn_async_destroying);
scn->scn_is_bptree = B_TRUE;
- scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
+ scn->scn_zio_root = zio_root(spa, NULL,
NULL, ZIO_FLAG_MUSTSUCCEED);
err = bptree_iterate(dp->dp_meta_objset,
dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
VERIFY0(zio_wait(scn->scn_zio_root));
+ scn->scn_zio_root = NULL;
if (err == EIO || err == ECKSUM) {
err = 0;
ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
}
- if (scn->scn_phys.scn_state != DSS_SCANNING)
+ if (!dsl_scan_is_running(scn) || dsl_scan_is_paused_scrub(scn))
return;
- if (scn->scn_done_txg == tx->tx_txg) {
- ASSERT(!scn->scn_suspending);
- /* finished with scan. */
- zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
- dsl_scan_done(scn, B_TRUE, tx);
- ASSERT3U(spa->spa_scrub_inflight, ==, 0);
- dsl_scan_sync_state(scn, tx);
+ /*
+ * Wait a few txgs after importing to begin scanning so that
+ * we can get the pool imported quickly.
+ */
+ if (spa->spa_syncing_txg < spa->spa_first_txg + SCAN_IMPORT_WAIT_TXGS)
return;
- }
- if (dsl_scan_is_paused_scrub(scn))
- return;
+ /*
+ * It is possible to switch from unsorted to sorted at any time,
+ * but afterwards the scan will remain sorted unless reloaded from
+ * a checkpoint after a reboot.
+ */
+ if (!zfs_scan_legacy) {
+ scn->scn_is_sorted = B_TRUE;
+ if (scn->scn_last_checkpoint == 0)
+ scn->scn_last_checkpoint = ddi_get_lbolt();
+ }
- if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
- scn->scn_phys.scn_ddt_class_max) {
- zfs_dbgmsg("doing scan sync txg %llu; "
- "ddt bm=%llu/%llu/%llu/%llx",
- (longlong_t)tx->tx_txg,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
- (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
- ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
- ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
- ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
- ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
+ /*
+ * For sorted scans, determine what kind of work we will be doing
+ * this txg based on our memory limitations and whether or not we
+ * need to perform a checkpoint.
+ */
+ if (scn->scn_is_sorted) {
+ /*
+ * If we are over our checkpoint interval, set scn_clearing
+ * so that we can begin checkpointing immediately. The
+ * checkpoint allows us to save a consisent bookmark
+ * representing how much data we have scrubbed so far.
+ * Otherwise, use the memory limit to determine if we should
+ * scan for metadata or start issue scrub IOs. We accumulate
+ * metadata until we hit our hard memory limit at which point
+ * we issue scrub IOs until we are at our soft memory limit.
+ */
+ if (scn->scn_checkpointing ||
+ ddi_get_lbolt() - scn->scn_last_checkpoint >
+ SEC_TO_TICK(zfs_scan_checkpoint_intval)) {
+ if (!scn->scn_checkpointing)
+ zfs_dbgmsg("begin scan checkpoint");
+
+ scn->scn_checkpointing = B_TRUE;
+ scn->scn_clearing = B_TRUE;
+ } else {
+ boolean_t should_clear = dsl_scan_should_clear(scn);
+ if (should_clear && !scn->scn_clearing) {
+ zfs_dbgmsg("begin scan clearing");
+ scn->scn_clearing = B_TRUE;
+ } else if (!should_clear && scn->scn_clearing) {
+ zfs_dbgmsg("finish scan clearing");
+ scn->scn_clearing = B_FALSE;
+ }
+ }
} else {
- zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
- (longlong_t)tx->tx_txg,
- (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
- (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
- (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
- (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
+ ASSERT0(scn->scn_checkpointing);
+ ASSERT0(scn->scn_clearing);
}
- scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
- NULL, ZIO_FLAG_CANFAIL);
- dsl_pool_config_enter(dp, FTAG);
- dsl_scan_visit(scn, tx);
- dsl_pool_config_exit(dp, FTAG);
- (void) zio_wait(scn->scn_zio_root);
- scn->scn_zio_root = NULL;
+ if (!scn->scn_clearing && scn->scn_done_txg == 0) {
+ /* Need to scan metadata for more blocks to scrub */
+ dsl_scan_phys_t *scnp = &scn->scn_phys;
+ taskqid_t prefetch_tqid;
+ uint64_t bytes_per_leaf = zfs_scan_vdev_limit;
+ uint64_t nr_leaves = dsl_scan_count_leaves(spa->spa_root_vdev);
- zfs_dbgmsg("visited %llu blocks in %llums",
- (longlong_t)scn->scn_visited_this_txg,
- (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
+ /*
+ * Calculate the max number of in-flight bytes for pool-wide
+ * scanning operations (minimum 1MB). Limits for the issuing
+ * phase are done per top-level vdev and are handled separately.
+ */
+ scn->scn_maxinflight_bytes =
+ MAX(nr_leaves * bytes_per_leaf, 1ULL << 20);
+
+ if (scnp->scn_ddt_bookmark.ddb_class <=
+ scnp->scn_ddt_class_max) {
+ ASSERT(ZB_IS_ZERO(&scnp->scn_bookmark));
+ zfs_dbgmsg("doing scan sync txg %llu; "
+ "ddt bm=%llu/%llu/%llu/%llx",
+ (longlong_t)tx->tx_txg,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
+ (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
+ } else {
+ zfs_dbgmsg("doing scan sync txg %llu; "
+ "bm=%llu/%llu/%llu/%llu",
+ (longlong_t)tx->tx_txg,
+ (longlong_t)scnp->scn_bookmark.zb_objset,
+ (longlong_t)scnp->scn_bookmark.zb_object,
+ (longlong_t)scnp->scn_bookmark.zb_level,
+ (longlong_t)scnp->scn_bookmark.zb_blkid);
+ }
- if (!scn->scn_suspending) {
- scn->scn_done_txg = tx->tx_txg + 1;
- zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
- tx->tx_txg, scn->scn_done_txg);
- }
+ scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
+ NULL, ZIO_FLAG_CANFAIL);
- if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
- mutex_enter(&spa->spa_scrub_lock);
- while (spa->spa_scrub_inflight > 0) {
- cv_wait(&spa->spa_scrub_io_cv,
- &spa->spa_scrub_lock);
- }
- mutex_exit(&spa->spa_scrub_lock);
- }
+ scn->scn_prefetch_stop = B_FALSE;
+ prefetch_tqid = taskq_dispatch(dp->dp_sync_taskq,
+ dsl_scan_prefetch_thread, scn, TQ_SLEEP);
+ ASSERT(prefetch_tqid != TASKQID_INVALID);
- dsl_scan_sync_state(scn, tx);
-}
+ dsl_pool_config_enter(dp, FTAG);
+ dsl_scan_visit(scn, tx);
+ dsl_pool_config_exit(dp, FTAG);
-/*
- * This will start a new scan, or restart an existing one.
- */
-void
-dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
-{
- if (txg == 0) {
- dmu_tx_t *tx;
- tx = dmu_tx_create_dd(dp->dp_mos_dir);
- VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
+ mutex_enter(&dp->dp_spa->spa_scrub_lock);
+ scn->scn_prefetch_stop = B_TRUE;
+ cv_broadcast(&spa->spa_scrub_io_cv);
+ mutex_exit(&dp->dp_spa->spa_scrub_lock);
- txg = dmu_tx_get_txg(tx);
- dp->dp_scan->scn_restart_txg = txg;
- dmu_tx_commit(tx);
- } else {
- dp->dp_scan->scn_restart_txg = txg;
+ taskq_wait_id(dp->dp_sync_taskq, prefetch_tqid);
+ (void) zio_wait(scn->scn_zio_root);
+ scn->scn_zio_root = NULL;
+
+ zfs_dbgmsg("scan visited %llu blocks in %llums "
+ "(%llu os's, %llu holes, %llu < mintxg, "
+ "%llu in ddt, %llu > maxtxg)",
+ (longlong_t)scn->scn_visited_this_txg,
+ (longlong_t)NSEC2MSEC(gethrtime() -
+ scn->scn_sync_start_time),
+ (longlong_t)scn->scn_objsets_visited_this_txg,
+ (longlong_t)scn->scn_holes_this_txg,
+ (longlong_t)scn->scn_lt_min_this_txg,
+ (longlong_t)scn->scn_ddt_contained_this_txg,
+ (longlong_t)scn->scn_gt_max_this_txg);
+
+ if (!scn->scn_suspending) {
+ ASSERT0(avl_numnodes(&scn->scn_queue));
+ scn->scn_done_txg = tx->tx_txg + 1;
+ if (scn->scn_is_sorted) {
+ scn->scn_checkpointing = B_TRUE;
+ scn->scn_clearing = B_TRUE;
+ }
+ zfs_dbgmsg("scan complete txg %llu",
+ (longlong_t)tx->tx_txg);
+ }
+ } else if (scn->scn_is_sorted && scn->scn_bytes_pending != 0) {
+ /* need to issue scrubbing IOs from per-vdev queues */
+ scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
+ NULL, ZIO_FLAG_CANFAIL);
+ scan_io_queues_run(scn);
+ (void) zio_wait(scn->scn_zio_root);
+ scn->scn_zio_root = NULL;
+
+ /* calculate and dprintf the current memory usage */
+ (void) dsl_scan_should_clear(scn);
+ dsl_scan_update_stats(scn);
+
+ zfs_dbgmsg("scan issued %llu blocks (%llu segs) in %llums "
+ "(avg_block_size = %llu, avg_seg_size = %llu)",
+ (longlong_t)scn->scn_zios_this_txg,
+ (longlong_t)scn->scn_segs_this_txg,
+ (longlong_t)NSEC2MSEC(gethrtime() -
+ scn->scn_sync_start_time),
+ (longlong_t)scn->scn_avg_zio_size_this_txg,
+ (longlong_t)scn->scn_avg_seg_size_this_txg);
+ } else if (scn->scn_done_txg != 0 && scn->scn_done_txg <= tx->tx_txg) {
+ /* Finished with everything. Mark the scrub as complete */
+ zfs_dbgmsg("scan issuing complete txg %llu",
+ (longlong_t)tx->tx_txg);
+ ASSERT3U(scn->scn_done_txg, !=, 0);
+ ASSERT0(spa->spa_scrub_inflight);
+ ASSERT0(scn->scn_bytes_pending);
+ dsl_scan_done(scn, B_TRUE, tx);
+ sync_type = SYNC_MANDATORY;
}
- zfs_dbgmsg("restarting resilver txg=%llu", txg);
-}
-boolean_t
-dsl_scan_resilvering(dsl_pool_t *dp)
-{
- return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
- dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
+ dsl_scan_sync_state(scn, tx, sync_type);
}
-/*
- * scrub consumers
- */
-
static void
-count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
+count_block(dsl_scan_t *scn, zfs_all_blkstats_t *zab, const blkptr_t *bp)
{
int i;
+ /* update the spa's stats on how many bytes we have issued */
+ for (i = 0; i < BP_GET_NDVAS(bp); i++) {
+ atomic_add_64(&scn->scn_dp->dp_spa->spa_scan_pass_issued,
+ DVA_GET_ASIZE(&bp->blk_dva[i]));
+ }
+
/*
* If we resume after a reboot, zab will be NULL; don't record
* incomplete stats in that case.
if (zab == NULL)
return;
+ mutex_enter(&zab->zab_lock);
+
for (i = 0; i < 4; i++) {
int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
break;
}
}
+
+ mutex_exit(&zab->zab_lock);
}
static void
-dsl_scan_scrub_done(zio_t *zio)
+scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue, scan_io_t *sio)
{
- spa_t *spa = zio->io_spa;
-
- abd_free(zio->io_abd);
+ avl_index_t idx;
+ int64_t asize = sio->sio_asize;
+ dsl_scan_t *scn = queue->q_scn;
- mutex_enter(&spa->spa_scrub_lock);
- spa->spa_scrub_inflight--;
- cv_broadcast(&spa->spa_scrub_io_cv);
+ ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
- if (zio->io_error && (zio->io_error != ECKSUM ||
- !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
- spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
+ if (avl_find(&queue->q_sios_by_addr, sio, &idx) != NULL) {
+ /* block is already scheduled for reading */
+ atomic_add_64(&scn->scn_bytes_pending, -asize);
+ kmem_cache_free(sio_cache, sio);
+ return;
}
- mutex_exit(&spa->spa_scrub_lock);
+ avl_insert(&queue->q_sios_by_addr, sio, idx);
+ range_tree_add(queue->q_exts_by_addr, sio->sio_offset, asize);
}
-static boolean_t
-dsl_scan_need_resilver(spa_t *spa, const dva_t *dva, size_t psize,
- uint64_t phys_birth)
+/*
+ * Given all the info we got from our metadata scanning process, we
+ * construct a scan_io_t and insert it into the scan sorting queue. The
+ * I/O must already be suitable for us to process. This is controlled
+ * by dsl_scan_enqueue().
+ */
+static void
+scan_io_queue_insert(dsl_scan_io_queue_t *queue, const blkptr_t *bp, int dva_i,
+ int zio_flags, const zbookmark_phys_t *zb)
{
- vdev_t *vd;
+ dsl_scan_t *scn = queue->q_scn;
+ scan_io_t *sio = kmem_cache_alloc(sio_cache, KM_SLEEP);
- if (DVA_GET_GANG(dva)) {
- /*
- * Gang members may be spread across multiple
- * vdevs, so the best estimate we have is the
- * scrub range, which has already been checked.
- * XXX -- it would be better to change our
- * allocation policy to ensure that all
- * gang members reside on the same vdev.
- */
- return (B_TRUE);
- }
+ ASSERT0(BP_IS_GANG(bp));
+ ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
- vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
+ bp2sio(bp, sio, dva_i);
+ sio->sio_flags = zio_flags;
+ sio->sio_zb = *zb;
/*
- * Check if the txg falls within the range which must be
- * resilvered. DVAs outside this range can always be skipped.
+ * Increment the bytes pending counter now so that we can't
+ * get an integer underflow in case the worker processes the
+ * zio before we get to incrementing this counter.
*/
- if (!vdev_dtl_contains(vd, DTL_PARTIAL, phys_birth, 1))
- return (B_FALSE);
+ atomic_add_64(&scn->scn_bytes_pending, sio->sio_asize);
+
+ scan_io_queue_insert_impl(queue, sio);
+}
+
+/*
+ * Given a set of I/O parameters as discovered by the metadata traversal
+ * process, attempts to place the I/O into the sorted queues (if allowed),
+ * or immediately executes the I/O.
+ */
+static void
+dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
+ const zbookmark_phys_t *zb)
+{
+ spa_t *spa = dp->dp_spa;
+
+ ASSERT(!BP_IS_EMBEDDED(bp));
/*
- * Check if the top-level vdev must resilver this offset.
- * When the offset does not intersect with a dirty leaf DTL
- * then it may be possible to skip the resilver IO. The psize
- * is provided instead of asize to simplify the check for RAIDZ.
+ * Gang blocks are hard to issue sequentially, so we just issue them
+ * here immediately instead of queuing them.
*/
- if (!vdev_dtl_need_resilver(vd, DVA_GET_OFFSET(dva), psize))
- return (B_FALSE);
+ if (!dp->dp_scan->scn_is_sorted || BP_IS_GANG(bp)) {
+ scan_exec_io(dp, bp, zio_flags, zb, NULL);
+ return;
+ }
- return (B_TRUE);
+ for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
+ dva_t dva;
+ vdev_t *vdev;
+
+ dva = bp->blk_dva[i];
+ vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&dva));
+ ASSERT(vdev != NULL);
+
+ mutex_enter(&vdev->vdev_scan_io_queue_lock);
+ if (vdev->vdev_scan_io_queue == NULL)
+ vdev->vdev_scan_io_queue = scan_io_queue_create(vdev);
+ ASSERT(dp->dp_scan != NULL);
+ scan_io_queue_insert(vdev->vdev_scan_io_queue, bp,
+ i, zio_flags, zb);
+ mutex_exit(&vdev->vdev_scan_io_queue_lock);
+ }
}
static int
const blkptr_t *bp, const zbookmark_phys_t *zb)
{
dsl_scan_t *scn = dp->dp_scan;
- size_t psize = BP_GET_PSIZE(bp);
spa_t *spa = dp->dp_spa;
uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
+ size_t psize = BP_GET_PSIZE(bp);
boolean_t needs_io = B_FALSE;
int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
- int scan_delay = 0;
if (phys_birth <= scn->scn_phys.scn_min_txg ||
phys_birth >= scn->scn_phys.scn_max_txg)
return (0);
- count_block(dp->dp_blkstats, bp);
-
- if (BP_IS_EMBEDDED(bp))
+ if (BP_IS_EMBEDDED(bp)) {
+ count_block(scn, dp->dp_blkstats, bp);
return (0);
+ }
ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
zio_flags |= ZIO_FLAG_SCRUB;
needs_io = B_TRUE;
- scan_delay = zfs_scrub_delay;
} else {
ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
zio_flags |= ZIO_FLAG_RESILVER;
needs_io = B_FALSE;
- scan_delay = zfs_resilver_delay;
}
/* If it's an intent log block, failure is expected. */
}
if (needs_io && !zfs_no_scrub_io) {
- vdev_t *rvd = spa->spa_root_vdev;
- uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
+ dsl_scan_enqueue(dp, bp, zio_flags, zb);
+ } else {
+ count_block(scn, dp->dp_blkstats, bp);
+ }
+
+ /* do not relocate this block */
+ return (0);
+}
+
+static void
+dsl_scan_scrub_done(zio_t *zio)
+{
+ spa_t *spa = zio->io_spa;
+ blkptr_t *bp = zio->io_bp;
+ dsl_scan_io_queue_t *queue = zio->io_private;
+
+ abd_free(zio->io_abd);
+
+ if (queue == NULL) {
+ mutex_enter(&spa->spa_scrub_lock);
+ ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
+ spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
+ cv_broadcast(&spa->spa_scrub_io_cv);
+ mutex_exit(&spa->spa_scrub_lock);
+ } else {
+ mutex_enter(&queue->q_vd->vdev_scan_io_queue_lock);
+ ASSERT3U(queue->q_inflight_bytes, >=, BP_GET_PSIZE(bp));
+ queue->q_inflight_bytes -= BP_GET_PSIZE(bp);
+ cv_broadcast(&queue->q_zio_cv);
+ mutex_exit(&queue->q_vd->vdev_scan_io_queue_lock);
+ }
+
+ if (zio->io_error && (zio->io_error != ECKSUM ||
+ !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
+ atomic_inc_64(&spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors);
+ }
+}
+/*
+ * Given a scanning zio's information, executes the zio. The zio need
+ * not necessarily be only sortable, this function simply executes the
+ * zio, no matter what it is. The optional queue argument allows the
+ * caller to specify that they want per top level vdev IO rate limiting
+ * instead of the legacy global limiting.
+ */
+static void
+scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
+ const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue)
+{
+ spa_t *spa = dp->dp_spa;
+ dsl_scan_t *scn = dp->dp_scan;
+ size_t size = BP_GET_PSIZE(bp);
+ abd_t *data = abd_alloc_for_io(size, B_FALSE);
+
+ if (queue == NULL) {
mutex_enter(&spa->spa_scrub_lock);
- while (spa->spa_scrub_inflight >= maxinflight)
+ while (spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)
cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
- spa->spa_scrub_inflight++;
+ spa->spa_scrub_inflight += BP_GET_PSIZE(bp);
mutex_exit(&spa->spa_scrub_lock);
+ } else {
+ kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_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);
+ mutex_enter(q_lock);
+ while (queue->q_inflight_bytes >= queue->q_maxinflight_bytes)
+ cv_wait(&queue->q_zio_cv, q_lock);
+ queue->q_inflight_bytes += BP_GET_PSIZE(bp);
+ mutex_exit(q_lock);
+ }
+
+ count_block(scn, dp->dp_blkstats, bp);
+ zio_nowait(zio_read(scn->scn_zio_root, spa, bp, data, size,
+ dsl_scan_scrub_done, queue, ZIO_PRIORITY_SCRUB, zio_flags, zb));
+}
- zio_nowait(zio_read(NULL, spa, bp,
- abd_alloc_for_io(psize, B_FALSE),
- psize, dsl_scan_scrub_done, NULL,
- ZIO_PRIORITY_SCRUB, zio_flags, zb));
+/*
+ * This is the primary extent sorting algorithm. We balance two parameters:
+ * 1) how many bytes of I/O are in an extent
+ * 2) how well the extent is filled with I/O (as a fraction of its total size)
+ * Since we allow extents to have gaps between their constituent I/Os, it's
+ * possible to have a fairly large extent that contains the same amount of
+ * I/O bytes than a much smaller extent, which just packs the I/O more tightly.
+ * The algorithm sorts based on a score calculated from the extent's size,
+ * the relative fill volume (in %) and a "fill weight" parameter that controls
+ * the split between whether we prefer larger extents or more well populated
+ * extents:
+ *
+ * SCORE = FILL_IN_BYTES + (FILL_IN_PERCENT * FILL_IN_BYTES * FILL_WEIGHT)
+ *
+ * Example:
+ * 1) assume extsz = 64 MiB
+ * 2) assume fill = 32 MiB (extent is half full)
+ * 3) assume fill_weight = 3
+ * 4) SCORE = 32M + (((32M * 100) / 64M) * 3 * 32M) / 100
+ * SCORE = 32M + (50 * 3 * 32M) / 100
+ * SCORE = 32M + (4800M / 100)
+ * SCORE = 32M + 48M
+ * ^ ^
+ * | +--- final total relative fill-based score
+ * +--------- final total fill-based score
+ * SCORE = 80M
+ *
+ * As can be seen, at fill_ratio=3, the algorithm is slightly biased towards
+ * extents that are more completely filled (in a 3:2 ratio) vs just larger.
+ * Note that as an optimization, we replace multiplication and division by
+ * 100 with bitshifting by 7 (which effecitvely multiplies and divides by 128).
+ */
+static int
+ext_size_compare(const void *x, const void *y)
+{
+ const range_seg_t *rsa = x, *rsb = y;
+ uint64_t sa = rsa->rs_end - rsa->rs_start,
+ sb = rsb->rs_end - rsb->rs_start;
+ uint64_t score_a, score_b;
+
+ score_a = rsa->rs_fill + ((((rsa->rs_fill << 7) / sa) *
+ fill_weight * rsa->rs_fill) >> 7);
+ score_b = rsb->rs_fill + ((((rsb->rs_fill << 7) / sb) *
+ fill_weight * rsb->rs_fill) >> 7);
+
+ if (score_a > score_b)
+ return (-1);
+ if (score_a == score_b) {
+ if (rsa->rs_start < rsb->rs_start)
+ return (-1);
+ if (rsa->rs_start == rsb->rs_start)
+ return (0);
+ return (1);
}
+ return (1);
+}
- /* do not relocate this block */
- return (0);
+/*
+ * Comparator for the q_sios_by_addr tree. Sorting is simply performed
+ * based on LBA-order (from lowest to highest).
+ */
+static int
+sio_addr_compare(const void *x, const void *y)
+{
+ const scan_io_t *a = x, *b = y;
+
+ if (a->sio_offset < b->sio_offset)
+ return (-1);
+ if (a->sio_offset == b->sio_offset)
+ return (0);
+ return (1);
+}
+
+/* IO queues are created on demand when they are needed. */
+static dsl_scan_io_queue_t *
+scan_io_queue_create(vdev_t *vd)
+{
+ dsl_scan_t *scn = vd->vdev_spa->spa_dsl_pool->dp_scan;
+ dsl_scan_io_queue_t *q = kmem_zalloc(sizeof (*q), KM_SLEEP);
+
+ q->q_scn = scn;
+ q->q_vd = vd;
+ cv_init(&q->q_zio_cv, NULL, CV_DEFAULT, NULL);
+ q->q_exts_by_addr = range_tree_create_impl(&rt_avl_ops,
+ &q->q_exts_by_size, ext_size_compare,
+ &q->q_vd->vdev_scan_io_queue_lock, zfs_scan_max_ext_gap);
+ avl_create(&q->q_sios_by_addr, sio_addr_compare,
+ sizeof (scan_io_t), offsetof(scan_io_t, sio_nodes.sio_addr_node));
+
+ return (q);
}
/*
- * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
- * Can also be called to resume a paused scrub.
+ * Destroys a scan queue and all segments and scan_io_t's contained in it.
+ * No further execution of I/O occurs, anything pending in the queue is
+ * simply freed without being executed.
*/
-int
-dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
+void
+dsl_scan_io_queue_destroy(dsl_scan_io_queue_t *queue)
{
- spa_t *spa = dp->dp_spa;
- dsl_scan_t *scn = dp->dp_scan;
+ dsl_scan_t *scn = queue->q_scn;
+ scan_io_t *sio;
+ void *cookie = NULL;
+ int64_t bytes_dequeued = 0;
+
+ ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
+
+ while ((sio = avl_destroy_nodes(&queue->q_sios_by_addr, &cookie)) !=
+ NULL) {
+ ASSERT(range_tree_contains(queue->q_exts_by_addr,
+ sio->sio_offset, sio->sio_asize));
+ bytes_dequeued += sio->sio_asize;
+ kmem_cache_free(sio_cache, sio);
+ }
- /*
- * Purge all vdev caches and probe all devices. We do this here
- * rather than in sync context because this requires a writer lock
- * on the spa_config lock, which we can't do from sync context. The
- * spa_scrub_reopen flag indicates that vdev_open() should not
- * attempt to start another scrub.
- */
- spa_vdev_state_enter(spa, SCL_NONE);
- spa->spa_scrub_reopen = B_TRUE;
- vdev_reopen(spa->spa_root_vdev);
- spa->spa_scrub_reopen = B_FALSE;
- (void) spa_vdev_state_exit(spa, NULL, 0);
+ atomic_add_64(&scn->scn_bytes_pending, -bytes_dequeued);
+ range_tree_vacate(queue->q_exts_by_addr, NULL, queue);
+ range_tree_destroy(queue->q_exts_by_addr);
+ avl_destroy(&queue->q_sios_by_addr);
+ cv_destroy(&queue->q_zio_cv);
- if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
- /* got scrub start cmd, resume paused scrub */
- int err = dsl_scrub_set_pause_resume(scn->scn_dp,
- POOL_SCRUB_NORMAL);
- if (err == 0)
- return (SET_ERROR(ECANCELED));
+ kmem_free(queue, sizeof (*queue));
+}
- return (SET_ERROR(err));
+/*
+ * Properly transfers a dsl_scan_queue_t from `svd' to `tvd'. This is
+ * called on behalf of vdev_top_transfer when creating or destroying
+ * a mirror vdev due to zpool attach/detach.
+ */
+void
+dsl_scan_io_queue_vdev_xfer(vdev_t *svd, vdev_t *tvd)
+{
+ mutex_enter(&svd->vdev_scan_io_queue_lock);
+ mutex_enter(&tvd->vdev_scan_io_queue_lock);
+
+ VERIFY3P(tvd->vdev_scan_io_queue, ==, NULL);
+ tvd->vdev_scan_io_queue = svd->vdev_scan_io_queue;
+ svd->vdev_scan_io_queue = NULL;
+ if (tvd->vdev_scan_io_queue != NULL) {
+ tvd->vdev_scan_io_queue->q_vd = tvd;
+ range_tree_set_lock(tvd->vdev_scan_io_queue->q_exts_by_addr,
+ &tvd->vdev_scan_io_queue_lock);
}
- return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
- dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));
+ mutex_exit(&tvd->vdev_scan_io_queue_lock);
+ mutex_exit(&svd->vdev_scan_io_queue_lock);
}
-static boolean_t
-dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
+static void
+scan_io_queues_destroy(dsl_scan_t *scn)
{
- return (scn->scn_restart_txg != 0 &&
- scn->scn_restart_txg <= tx->tx_txg);
+ vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
+
+ for (uint64_t i = 0; i < rvd->vdev_children; i++) {
+ vdev_t *tvd = rvd->vdev_child[i];
+
+ mutex_enter(&tvd->vdev_scan_io_queue_lock);
+ if (tvd->vdev_scan_io_queue != NULL)
+ dsl_scan_io_queue_destroy(tvd->vdev_scan_io_queue);
+ tvd->vdev_scan_io_queue = NULL;
+ mutex_exit(&tvd->vdev_scan_io_queue_lock);
+ }
}
-#if defined(_KERNEL) && defined(HAVE_SPL)
-module_param(zfs_top_maxinflight, int, 0644);
-MODULE_PARM_DESC(zfs_top_maxinflight, "Max I/Os per top-level");
+static void
+dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i)
+{
+ dsl_pool_t *dp = spa->spa_dsl_pool;
+ dsl_scan_t *scn = dp->dp_scan;
+ vdev_t *vdev;
+ kmutex_t *q_lock;
+ dsl_scan_io_queue_t *queue;
+ scan_io_t srch, *sio;
+ avl_index_t idx;
+ uint64_t start, size;
+
+ vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[dva_i]));
+ ASSERT(vdev != NULL);
+ q_lock = &vdev->vdev_scan_io_queue_lock;
+ queue = vdev->vdev_scan_io_queue;
+
+ mutex_enter(q_lock);
+ if (queue == NULL) {
+ mutex_exit(q_lock);
+ return;
+ }
+
+ bp2sio(bp, &srch, dva_i);
+ start = srch.sio_offset;
+ size = srch.sio_asize;
+
+ /*
+ * We can find the zio in two states:
+ * 1) Cold, just sitting in the queue of zio's to be issued at
+ * some point in the future. In this case, all we do is
+ * remove the zio from the q_sios_by_addr tree, decrement
+ * its data volume from the containing range_seg_t and
+ * resort the q_exts_by_size tree to reflect that the
+ * range_seg_t has lost some of its 'fill'. We don't shorten
+ * the range_seg_t - this is usually rare enough not to be
+ * worth the extra hassle of trying keep track of precise
+ * extent boundaries.
+ * 2) Hot, where the zio is currently in-flight in
+ * dsl_scan_issue_ios. In this case, we can't simply
+ * reach in and stop the in-flight zio's, so we instead
+ * block the caller. Eventually, dsl_scan_issue_ios will
+ * be done with issuing the zio's it gathered and will
+ * signal us.
+ */
+ sio = avl_find(&queue->q_sios_by_addr, &srch, &idx);
+ if (sio != NULL) {
+ int64_t asize = sio->sio_asize;
+ blkptr_t tmpbp;
+
+ /* Got it while it was cold in the queue */
+ ASSERT3U(start, ==, sio->sio_offset);
+ ASSERT3U(size, ==, asize);
+ avl_remove(&queue->q_sios_by_addr, sio);
-module_param(zfs_resilver_delay, int, 0644);
-MODULE_PARM_DESC(zfs_resilver_delay, "Number of ticks to delay resilver");
+ ASSERT(range_tree_contains(queue->q_exts_by_addr, start, size));
+ range_tree_remove_fill(queue->q_exts_by_addr, start, size);
+
+ /*
+ * We only update scn_bytes_pending in the cold path,
+ * otherwise it will already have been accounted for as
+ * part of the zio's execution.
+ */
+ atomic_add_64(&scn->scn_bytes_pending, -asize);
-module_param(zfs_scrub_delay, int, 0644);
-MODULE_PARM_DESC(zfs_scrub_delay, "Number of ticks to delay scrub");
+ /* count the block as though we issued it */
+ sio2bp(sio, &tmpbp, dva_i);
+ count_block(scn, dp->dp_blkstats, &tmpbp);
-module_param(zfs_scan_idle, int, 0644);
-MODULE_PARM_DESC(zfs_scan_idle, "Idle window in clock ticks");
+ kmem_cache_free(sio_cache, sio);
+ }
+ mutex_exit(q_lock);
+}
-module_param(zfs_scan_min_time_ms, int, 0644);
-MODULE_PARM_DESC(zfs_scan_min_time_ms, "Min millisecs to scrub per txg");
+/*
+ * Callback invoked when a zio_free() zio is executing. This needs to be
+ * intercepted to prevent the zio from deallocating a particular portion
+ * of disk space and it then getting reallocated and written to, while we
+ * still have it queued up for processing.
+ */
+void
+dsl_scan_freed(spa_t *spa, const blkptr_t *bp)
+{
+ dsl_pool_t *dp = spa->spa_dsl_pool;
+ dsl_scan_t *scn = dp->dp_scan;
+
+ ASSERT(!BP_IS_EMBEDDED(bp));
+ ASSERT(scn != NULL);
+ if (!dsl_scan_is_running(scn))
+ return;
+
+ for (int i = 0; i < BP_GET_NDVAS(bp); i++)
+ dsl_scan_freed_dva(spa, bp, i);
+}
+
+#if defined(_KERNEL) && defined(HAVE_SPL)
+/* CSTYLED */
+module_param(zfs_scan_vdev_limit, ulong, 0644);
+MODULE_PARM_DESC(zfs_scan_vdev_limit,
+ "Max bytes in flight per leaf vdev for scrubs and resilvers");
+
+module_param(zfs_scrub_min_time_ms, int, 0644);
+MODULE_PARM_DESC(zfs_scrub_min_time_ms, "Min millisecs to scrub per txg");
module_param(zfs_free_min_time_ms, int, 0644);
MODULE_PARM_DESC(zfs_free_min_time_ms, "Min millisecs to free per txg");
module_param(zfs_free_bpobj_enabled, int, 0644);
MODULE_PARM_DESC(zfs_free_bpobj_enabled, "Enable processing of the free_bpobj");
+
+module_param(zfs_scan_mem_lim_fact, int, 0644);
+MODULE_PARM_DESC(zfs_scan_mem_lim_fact, "Fraction of RAM for scan hard limit");
+
+module_param(zfs_scan_issue_strategy, int, 0644);
+MODULE_PARM_DESC(zfs_scan_issue_strategy,
+ "IO issuing strategy during scrubbing. 0 = default, 1 = LBA, 2 = size");
+
+module_param(zfs_scan_legacy, int, 0644);
+MODULE_PARM_DESC(zfs_scan_legacy, "Scrub using legacy non-sequential method");
+
+module_param(zfs_scan_checkpoint_intval, int, 0644);
+MODULE_PARM_DESC(zfs_scan_checkpoint_intval,
+ "Scan progress on-disk checkpointing interval");
+
+module_param(zfs_scan_mem_lim_soft_fact, int, 0644);
+MODULE_PARM_DESC(zfs_scan_mem_lim_soft_fact,
+ "Fraction of hard limit used as soft limit");
+
+module_param(zfs_scan_strict_mem_lim, int, 0644);
+MODULE_PARM_DESC(zfs_scan_strict_mem_lim,
+ "Tunable to attempt to reduce lock contention");
+
+module_param(zfs_scan_fill_weight, int, 0644);
+MODULE_PARM_DESC(zfs_scan_fill_weight,
+ "Tunable to adjust bias towards more filled segments during scans");
#endif
projects / mirror_zfs.git / commitdiff