return (AVL_CMP(m1->ms_start, m2->ms_start));
}
+uint64_t
+metaslab_allocated_space(metaslab_t *msp)
+{
+ return (msp->ms_allocated_space);
+}
+
/*
* Verify that the space accounting on disk matches the in-core range_trees.
*/
-void
+static void
metaslab_verify_space(metaslab_t *msp, uint64_t txg)
{
spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
- uint64_t allocated = 0;
+ uint64_t allocating = 0;
uint64_t sm_free_space, msp_free_space;
ASSERT(MUTEX_HELD(&msp->ms_lock));
+ ASSERT(!msp->ms_condensing);
if ((zfs_flags & ZFS_DEBUG_METASLAB_VERIFY) == 0)
return;
/*
* We can only verify the metaslab space when we're called
- * from syncing context with a loaded metaslab that has an allocated
- * space map. Calling this in non-syncing context does not
- * provide a consistent view of the metaslab since we're performing
- * allocations in the future.
+ * from syncing context with a loaded metaslab that has an
+ * allocated space map. Calling this in non-syncing context
+ * does not provide a consistent view of the metaslab since
+ * we're performing allocations in the future.
*/
if (txg != spa_syncing_txg(spa) || msp->ms_sm == NULL ||
!msp->ms_loaded)
return;
- sm_free_space = msp->ms_size - space_map_allocated(msp->ms_sm) -
- space_map_alloc_delta(msp->ms_sm);
+ /*
+ * Even though the smp_alloc field can get negative (e.g.
+ * see vdev_checkpoint_sm), that should never be the case
+ * when it come's to a metaslab's space map.
+ */
+ ASSERT3S(space_map_allocated(msp->ms_sm), >=, 0);
+
+ sm_free_space = msp->ms_size - metaslab_allocated_space(msp);
/*
- * Account for future allocations since we would have already
- * deducted that space from the ms_freetree.
+ * Account for future allocations since we would have
+ * already deducted that space from the ms_allocatable.
*/
for (int t = 0; t < TXG_CONCURRENT_STATES; t++) {
- allocated +=
+ allocating +=
range_tree_space(msp->ms_allocating[(txg + t) & TXG_MASK]);
}
- msp_free_space = range_tree_space(msp->ms_allocatable) + allocated +
+ ASSERT3U(msp->ms_deferspace, ==,
+ range_tree_space(msp->ms_defer[0]) +
+ range_tree_space(msp->ms_defer[1]));
+
+ msp_free_space = range_tree_space(msp->ms_allocatable) + allocating +
msp->ms_deferspace + range_tree_space(msp->ms_freed);
VERIFY3U(sm_free_space, ==, msp_free_space);
ASSERT(MUTEX_HELD(&msp->ms_lock));
ASSERT(msp->ms_loading);
+ ASSERT(!msp->ms_condensing);
/*
- * Nobody else can manipulate a loading metaslab, so it's now safe
- * to drop the lock. This way we don't have to hold the lock while
- * reading the spacemap from disk.
+ * We temporarily drop the lock to unblock other operations while we
+ * are reading the space map. Therefore, metaslab_sync() and
+ * metaslab_sync_done() can run at the same time as we do.
+ *
+ * metaslab_sync() can append to the space map while we are loading.
+ * Therefore we load only entries that existed when we started the
+ * load. Additionally, metaslab_sync_done() has to wait for the load
+ * to complete because there are potential races like metaslab_load()
+ * loading parts of the space map that are currently being appended
+ * by metaslab_sync(). If we didn't, the ms_allocatable would have
+ * entries that metaslab_sync_done() would try to re-add later.
+ *
+ * That's why before dropping the lock we remember the synced length
+ * of the metaslab and read up to that point of the space map,
+ * ignoring entries appended by metaslab_sync() that happen after we
+ * drop the lock.
*/
+ uint64_t length = msp->ms_synced_length;
mutex_exit(&msp->ms_lock);
- /*
- * If the space map has not been allocated yet, then treat
- * all the space in the metaslab as free and add it to ms_allocatable.
- */
if (msp->ms_sm != NULL) {
- error = space_map_load(msp->ms_sm, msp->ms_allocatable,
- SM_FREE);
+ error = space_map_load_length(msp->ms_sm, msp->ms_allocatable,
+ SM_FREE, length);
} else {
+ /*
+ * The space map has not been allocated yet, so treat
+ * all the space in the metaslab as free and add it to the
+ * ms_allocatable tree.
+ */
range_tree_add(msp->ms_allocatable,
msp->ms_start, msp->ms_size);
}
+ /*
+ * We need to grab the ms_sync_lock to prevent metaslab_sync() from
+ * changing the ms_sm and the metaslab's range trees while we are
+ * about to use them and populate the ms_allocatable. The ms_lock
+ * is insufficient for this because metaslab_sync() doesn't hold
+ * the ms_lock while writing the ms_checkpointing tree to disk.
+ */
+ mutex_enter(&msp->ms_sync_lock);
mutex_enter(&msp->ms_lock);
+ ASSERT(!msp->ms_condensing);
if (error != 0)
return (error);
msp->ms_loaded = B_TRUE;
/*
- * If the metaslab already has a spacemap, then we need to
- * remove all segments from the defer tree; otherwise, the
- * metaslab is completely empty and we can skip this.
+ * The ms_allocatable contains the segments that exist in the
+ * ms_defer trees [see ms_synced_length]. Thus we need to remove
+ * them from ms_allocatable as they will be added again in
+ * metaslab_sync_done().
*/
- if (msp->ms_sm != NULL) {
- for (int t = 0; t < TXG_DEFER_SIZE; t++) {
- range_tree_walk(msp->ms_defer[t],
- range_tree_remove, msp->ms_allocatable);
- }
+ for (int t = 0; t < TXG_DEFER_SIZE; t++) {
+ range_tree_walk(msp->ms_defer[t],
+ range_tree_remove, msp->ms_allocatable);
}
+
msp->ms_max_size = metaslab_block_maxsize(msp);
+ spa_t *spa = msp->ms_group->mg_vd->vdev_spa;
+ metaslab_verify_space(msp, spa_syncing_txg(spa));
+ mutex_exit(&msp->ms_sync_lock);
+
return (0);
}
if (msp->ms_loaded)
return (0);
VERIFY(!msp->ms_loading);
+ ASSERT(!msp->ms_condensing);
msp->ms_loading = B_TRUE;
int error = metaslab_load_impl(msp);
/*
* We only open space map objects that already exist. All others
* will be opened when we finally allocate an object for it.
+ *
+ * Note:
+ * When called from vdev_expand(), we can't call into the DMU as
+ * we are holding the spa_config_lock as a writer and we would
+ * deadlock [see relevant comment in vdev_metaslab_init()]. in
+ * that case, the object parameter is zero though, so we won't
+ * call into the DMU.
*/
if (object != 0) {
error = space_map_open(&ms->ms_sm, mos, object, ms->ms_start,
}
ASSERT(ms->ms_sm != NULL);
+ ms->ms_allocated_space = space_map_allocated(ms->ms_sm);
}
/*
- * We create the main range tree here, but we don't create the
+ * We create the ms_allocatable here, but we don't create the
* other range trees until metaslab_sync_done(). This serves
* two purposes: it allows metaslab_sync_done() to detect the
- * addition of new space; and for debugging, it ensures that we'd
- * data fault on any attempt to use this metaslab before it's ready.
+ * addition of new space; and for debugging, it ensures that
+ * we'd data fault on any attempt to use this metaslab before
+ * it's ready.
*/
ms->ms_allocatable = range_tree_create_impl(&rt_avl_ops,
&ms->ms_allocatable_by_size, metaslab_rangesize_compare, 0);
* out this txg. This ensures that we don't attempt to allocate
* from it before we have initialized it completely.
*/
- if (txg <= TXG_INITIAL)
+ if (txg <= TXG_INITIAL) {
metaslab_sync_done(ms, 0);
+ metaslab_space_update(vd, mg->mg_class,
+ metaslab_allocated_space(ms), 0, 0);
+ }
/*
* If metaslab_debug_load is set and we're initializing a metaslab
mutex_enter(&msp->ms_lock);
VERIFY(msp->ms_group == NULL);
metaslab_space_update(vd, mg->mg_class,
- -space_map_allocated(msp->ms_sm), 0, -msp->ms_size);
+ -metaslab_allocated_space(msp), 0, -msp->ms_size);
space_map_close(msp->ms_sm);
};
/*
- * Calclate the metaslab's fragmentation metric. A return value
- * of ZFS_FRAG_INVALID means that the metaslab has not been upgraded and does
- * not support this metric. Otherwise, the return value should be in the
- * range [0, 100].
+ * Calculate the metaslab's fragmentation metric and set ms_fragmentation.
+ * Setting this value to ZFS_FRAG_INVALID means that the metaslab has not
+ * been upgraded and does not support this metric. Otherwise, the return
+ * value should be in the range [0, 100].
*/
static void
metaslab_set_fragmentation(metaslab_t *msp)
/*
* The baseline weight is the metaslab's free space.
*/
- space = msp->ms_size - space_map_allocated(msp->ms_sm);
+ space = msp->ms_size - metaslab_allocated_space(msp);
if (metaslab_fragmentation_factor_enabled &&
msp->ms_fragmentation != ZFS_FRAG_INVALID) {
/*
* The metaslab is completely free.
*/
- if (space_map_allocated(msp->ms_sm) == 0) {
+ if (metaslab_allocated_space(msp) == 0) {
int idx = highbit64(msp->ms_size) - 1;
int max_idx = SPACE_MAP_HISTOGRAM_SIZE + shift - 1;
/*
* If the metaslab is fully allocated then just make the weight 0.
*/
- if (space_map_allocated(msp->ms_sm) == msp->ms_size)
+ if (metaslab_allocated_space(msp) == msp->ms_size)
return (0);
/*
* If the metaslab is already loaded, then use the range tree to
*/
if (msp->ms_loaded)
msp->ms_max_size = metaslab_block_maxsize(msp);
+ else
+ ASSERT0(msp->ms_max_size);
/*
* Segment-based weighting requires space map histogram support.
VERIFY(txg <= spa_final_dirty_txg(spa));
/*
- * The only state that can actually be changing concurrently with
- * metaslab_sync() is the metaslab's ms_allocatable. No other
- * thread can be modifying this txg's alloc, freeing,
+ * The only state that can actually be changing concurrently
+ * with metaslab_sync() is the metaslab's ms_allocatable. No
+ * other thread can be modifying this txg's alloc, freeing,
* freed, or space_map_phys_t. We drop ms_lock whenever we
- * could call into the DMU, because the DMU can call down to us
- * (e.g. via zio_free()) at any time.
+ * could call into the DMU, because the DMU can call down to
+ * us (e.g. via zio_free()) at any time.
*
* The spa_vdev_remove_thread() can be reading metaslab state
- * concurrently, and it is locked out by the ms_sync_lock. Note
- * that the ms_lock is insufficient for this, because it is dropped
- * by space_map_write().
+ * concurrently, and it is locked out by the ms_sync_lock.
+ * Note that the ms_lock is insufficient for this, because it
+ * is dropped by space_map_write().
*/
tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
VERIFY0(space_map_open(&msp->ms_sm, mos, new_object,
msp->ms_start, msp->ms_size, vd->vdev_ashift));
+
ASSERT(msp->ms_sm != NULL);
+ ASSERT0(metaslab_allocated_space(msp));
}
if (!range_tree_is_empty(msp->ms_checkpointing) &&
mutex_enter(&msp->ms_lock);
}
+ msp->ms_allocated_space += range_tree_space(alloctree);
+ ASSERT3U(msp->ms_allocated_space, >=,
+ range_tree_space(msp->ms_freeing));
+ msp->ms_allocated_space -= range_tree_space(msp->ms_freeing);
+
if (!range_tree_is_empty(msp->ms_checkpointing)) {
ASSERT(spa_has_checkpoint(spa));
ASSERT3P(vd->vdev_checkpoint_sm, !=, NULL);
space_map_write(vd->vdev_checkpoint_sm,
msp->ms_checkpointing, SM_FREE, SM_NO_VDEVID, tx);
mutex_enter(&msp->ms_lock);
- space_map_update(vd->vdev_checkpoint_sm);
spa->spa_checkpoint_info.sci_dspace +=
range_tree_space(msp->ms_checkpointing);
vd->vdev_stat.vs_checkpoint_space +=
range_tree_space(msp->ms_checkpointing);
ASSERT3U(vd->vdev_stat.vs_checkpoint_space, ==,
- -vd->vdev_checkpoint_sm->sm_alloc);
+ -space_map_allocated(vd->vdev_checkpoint_sm));
range_tree_vacate(msp->ms_checkpointing, NULL, NULL);
}
/*
* For sync pass 1, we avoid traversing this txg's free range tree
- * and instead will just swap the pointers for freeing and
- * freed. We can safely do this since the freed_tree is
- * guaranteed to be empty on the initial pass.
+ * and instead will just swap the pointers for freeing and freed.
+ * We can safely do this since the freed_tree is guaranteed to be
+ * empty on the initial pass.
*/
if (spa_sync_pass(spa) == 1) {
range_tree_swap(&msp->ms_freeing, &msp->ms_freed);
+ ASSERT0(msp->ms_allocated_this_txg);
} else {
range_tree_vacate(msp->ms_freeing,
range_tree_add, msp->ms_freed);
}
+ msp->ms_allocated_this_txg += range_tree_space(alloctree);
range_tree_vacate(alloctree, NULL, NULL);
ASSERT0(range_tree_space(msp->ms_allocating[txg & TXG_MASK]));
}
defer_delta = 0;
- alloc_delta = space_map_alloc_delta(msp->ms_sm);
+ alloc_delta = msp->ms_allocated_this_txg -
+ range_tree_space(msp->ms_freed);
if (defer_allowed) {
defer_delta = range_tree_space(msp->ms_freed) -
range_tree_space(*defer_tree);
msp->ms_loaded ? range_tree_add : NULL,
msp->ms_allocatable);
}
- space_map_update(msp->ms_sm);
+
+ msp->ms_synced_length = space_map_length(msp->ms_sm);
msp->ms_deferspace += defer_delta;
ASSERT3S(msp->ms_deferspace, >=, 0);
ASSERT0(range_tree_space(msp->ms_freed));
ASSERT0(range_tree_space(msp->ms_checkpointing));
+ msp->ms_allocated_this_txg = 0;
mutex_exit(&msp->ms_lock);
}
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