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Diffstat (limited to 'module/zfs/dbuf.c')
| -rw-r--r-- | module/zfs/dbuf.c | 4741 |
1 files changed, 4741 insertions, 0 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c new file mode 100644 index 000000000000..2de1f4e4c267 --- /dev/null +++ b/module/zfs/dbuf.c @@ -0,0 +1,4741 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. + * Copyright 2011 Nexenta Systems, Inc. All rights reserved. + * Copyright (c) 2012, 2019 by Delphix. All rights reserved. + * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. + * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. + * Copyright (c) 2019, Klara Inc. + * Copyright (c) 2019, Allan Jude + */ + +#include <sys/zfs_context.h> +#include <sys/arc.h> +#include <sys/dmu.h> +#include <sys/dmu_send.h> +#include <sys/dmu_impl.h> +#include <sys/dbuf.h> +#include <sys/dmu_objset.h> +#include <sys/dsl_dataset.h> +#include <sys/dsl_dir.h> +#include <sys/dmu_tx.h> +#include <sys/spa.h> +#include <sys/zio.h> +#include <sys/dmu_zfetch.h> +#include <sys/sa.h> +#include <sys/sa_impl.h> +#include <sys/zfeature.h> +#include <sys/blkptr.h> +#include <sys/range_tree.h> +#include <sys/trace_zfs.h> +#include <sys/callb.h> +#include <sys/abd.h> +#include <sys/vdev.h> +#include <cityhash.h> +#include <sys/spa_impl.h> + +kstat_t *dbuf_ksp; + +typedef struct dbuf_stats { + /* + * Various statistics about the size of the dbuf cache. + */ + kstat_named_t cache_count; + kstat_named_t cache_size_bytes; + kstat_named_t cache_size_bytes_max; + /* + * Statistics regarding the bounds on the dbuf cache size. + */ + kstat_named_t cache_target_bytes; + kstat_named_t cache_lowater_bytes; + kstat_named_t cache_hiwater_bytes; + /* + * Total number of dbuf cache evictions that have occurred. + */ + kstat_named_t cache_total_evicts; + /* + * The distribution of dbuf levels in the dbuf cache and + * the total size of all dbufs at each level. + */ + kstat_named_t cache_levels[DN_MAX_LEVELS]; + kstat_named_t cache_levels_bytes[DN_MAX_LEVELS]; + /* + * Statistics about the dbuf hash table. + */ + kstat_named_t hash_hits; + kstat_named_t hash_misses; + kstat_named_t hash_collisions; + kstat_named_t hash_elements; + kstat_named_t hash_elements_max; + /* + * Number of sublists containing more than one dbuf in the dbuf + * hash table. Keep track of the longest hash chain. + */ + kstat_named_t hash_chains; + kstat_named_t hash_chain_max; + /* + * Number of times a dbuf_create() discovers that a dbuf was + * already created and in the dbuf hash table. + */ + kstat_named_t hash_insert_race; + /* + * Statistics about the size of the metadata dbuf cache. + */ + kstat_named_t metadata_cache_count; + kstat_named_t metadata_cache_size_bytes; + kstat_named_t metadata_cache_size_bytes_max; + /* + * For diagnostic purposes, this is incremented whenever we can't add + * something to the metadata cache because it's full, and instead put + * the data in the regular dbuf cache. + */ + kstat_named_t metadata_cache_overflow; +} dbuf_stats_t; + +dbuf_stats_t dbuf_stats = { + { "cache_count", KSTAT_DATA_UINT64 }, + { "cache_size_bytes", KSTAT_DATA_UINT64 }, + { "cache_size_bytes_max", KSTAT_DATA_UINT64 }, + { "cache_target_bytes", KSTAT_DATA_UINT64 }, + { "cache_lowater_bytes", KSTAT_DATA_UINT64 }, + { "cache_hiwater_bytes", KSTAT_DATA_UINT64 }, + { "cache_total_evicts", KSTAT_DATA_UINT64 }, + { { "cache_levels_N", KSTAT_DATA_UINT64 } }, + { { "cache_levels_bytes_N", KSTAT_DATA_UINT64 } }, + { "hash_hits", KSTAT_DATA_UINT64 }, + { "hash_misses", KSTAT_DATA_UINT64 }, + { "hash_collisions", KSTAT_DATA_UINT64 }, + { "hash_elements", KSTAT_DATA_UINT64 }, + { "hash_elements_max", KSTAT_DATA_UINT64 }, + { "hash_chains", KSTAT_DATA_UINT64 }, + { "hash_chain_max", KSTAT_DATA_UINT64 }, + { "hash_insert_race", KSTAT_DATA_UINT64 }, + { "metadata_cache_count", KSTAT_DATA_UINT64 }, + { "metadata_cache_size_bytes", KSTAT_DATA_UINT64 }, + { "metadata_cache_size_bytes_max", KSTAT_DATA_UINT64 }, + { "metadata_cache_overflow", KSTAT_DATA_UINT64 } +}; + +#define DBUF_STAT_INCR(stat, val) \ + atomic_add_64(&dbuf_stats.stat.value.ui64, (val)); +#define DBUF_STAT_DECR(stat, val) \ + DBUF_STAT_INCR(stat, -(val)); +#define DBUF_STAT_BUMP(stat) \ + DBUF_STAT_INCR(stat, 1); +#define DBUF_STAT_BUMPDOWN(stat) \ + DBUF_STAT_INCR(stat, -1); +#define DBUF_STAT_MAX(stat, v) { \ + uint64_t _m; \ + while ((v) > (_m = dbuf_stats.stat.value.ui64) && \ + (_m != atomic_cas_64(&dbuf_stats.stat.value.ui64, _m, (v))))\ + continue; \ +} + +static boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx); +static void dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx); +static void dbuf_sync_leaf_verify_bonus_dnode(dbuf_dirty_record_t *dr); +static int dbuf_read_verify_dnode_crypt(dmu_buf_impl_t *db, uint32_t flags); + +extern inline void dmu_buf_init_user(dmu_buf_user_t *dbu, + dmu_buf_evict_func_t *evict_func_sync, + dmu_buf_evict_func_t *evict_func_async, + dmu_buf_t **clear_on_evict_dbufp); + +/* + * Global data structures and functions for the dbuf cache. + */ +static kmem_cache_t *dbuf_kmem_cache; +static taskq_t *dbu_evict_taskq; + +static kthread_t *dbuf_cache_evict_thread; +static kmutex_t dbuf_evict_lock; +static kcondvar_t dbuf_evict_cv; +static boolean_t dbuf_evict_thread_exit; + +/* + * There are two dbuf caches; each dbuf can only be in one of them at a time. + * + * 1. Cache of metadata dbufs, to help make read-heavy administrative commands + * from /sbin/zfs run faster. The "metadata cache" specifically stores dbufs + * that represent the metadata that describes filesystems/snapshots/ + * bookmarks/properties/etc. We only evict from this cache when we export a + * pool, to short-circuit as much I/O as possible for all administrative + * commands that need the metadata. There is no eviction policy for this + * cache, because we try to only include types in it which would occupy a + * very small amount of space per object but create a large impact on the + * performance of these commands. Instead, after it reaches a maximum size + * (which should only happen on very small memory systems with a very large + * number of filesystem objects), we stop taking new dbufs into the + * metadata cache, instead putting them in the normal dbuf cache. + * + * 2. LRU cache of dbufs. The dbuf cache maintains a list of dbufs that + * are not currently held but have been recently released. These dbufs + * are not eligible for arc eviction until they are aged out of the cache. + * Dbufs that are aged out of the cache will be immediately destroyed and + * become eligible for arc eviction. + * + * Dbufs are added to these caches once the last hold is released. If a dbuf is + * later accessed and still exists in the dbuf cache, then it will be removed + * from the cache and later re-added to the head of the cache. + * + * If a given dbuf meets the requirements for the metadata cache, it will go + * there, otherwise it will be considered for the generic LRU dbuf cache. The + * caches and the refcounts tracking their sizes are stored in an array indexed + * by those caches' matching enum values (from dbuf_cached_state_t). + */ +typedef struct dbuf_cache { + multilist_t *cache; + zfs_refcount_t size; +} dbuf_cache_t; +dbuf_cache_t dbuf_caches[DB_CACHE_MAX]; + +/* Size limits for the caches */ +unsigned long dbuf_cache_max_bytes = ULONG_MAX; +unsigned long dbuf_metadata_cache_max_bytes = ULONG_MAX; + +/* Set the default sizes of the caches to log2 fraction of arc size */ +int dbuf_cache_shift = 5; +int dbuf_metadata_cache_shift = 6; + +static unsigned long dbuf_cache_target_bytes(void); +static unsigned long dbuf_metadata_cache_target_bytes(void); + +/* + * The LRU dbuf cache uses a three-stage eviction policy: + * - A low water marker designates when the dbuf eviction thread + * should stop evicting from the dbuf cache. + * - When we reach the maximum size (aka mid water mark), we + * signal the eviction thread to run. + * - The high water mark indicates when the eviction thread + * is unable to keep up with the incoming load and eviction must + * happen in the context of the calling thread. + * + * The dbuf cache: + * (max size) + * low water mid water hi water + * +----------------------------------------+----------+----------+ + * | | | | + * | | | | + * | | | | + * | | | | + * +----------------------------------------+----------+----------+ + * stop signal evict + * evicting eviction directly + * thread + * + * The high and low water marks indicate the operating range for the eviction + * thread. The low water mark is, by default, 90% of the total size of the + * cache and the high water mark is at 110% (both of these percentages can be + * changed by setting dbuf_cache_lowater_pct and dbuf_cache_hiwater_pct, + * respectively). The eviction thread will try to ensure that the cache remains + * within this range by waking up every second and checking if the cache is + * above the low water mark. The thread can also be woken up by callers adding + * elements into the cache if the cache is larger than the mid water (i.e max + * cache size). Once the eviction thread is woken up and eviction is required, + * it will continue evicting buffers until it's able to reduce the cache size + * to the low water mark. If the cache size continues to grow and hits the high + * water mark, then callers adding elements to the cache will begin to evict + * directly from the cache until the cache is no longer above the high water + * mark. + */ + +/* + * The percentage above and below the maximum cache size. + */ +uint_t dbuf_cache_hiwater_pct = 10; +uint_t dbuf_cache_lowater_pct = 10; + +/* ARGSUSED */ +static int +dbuf_cons(void *vdb, void *unused, int kmflag) +{ + dmu_buf_impl_t *db = vdb; + bzero(db, sizeof (dmu_buf_impl_t)); + + mutex_init(&db->db_mtx, NULL, MUTEX_DEFAULT, NULL); + rw_init(&db->db_rwlock, NULL, RW_DEFAULT, NULL); + cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL); + multilist_link_init(&db->db_cache_link); + zfs_refcount_create(&db->db_holds); + + return (0); +} + +/* ARGSUSED */ +static void +dbuf_dest(void *vdb, void *unused) +{ + dmu_buf_impl_t *db = vdb; + mutex_destroy(&db->db_mtx); + rw_destroy(&db->db_rwlock); + cv_destroy(&db->db_changed); + ASSERT(!multilist_link_active(&db->db_cache_link)); + zfs_refcount_destroy(&db->db_holds); +} + +/* + * dbuf hash table routines + */ +static dbuf_hash_table_t dbuf_hash_table; + +static uint64_t dbuf_hash_count; + +/* + * We use Cityhash for this. It's fast, and has good hash properties without + * requiring any large static buffers. + */ +static uint64_t +dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid) +{ + return (cityhash4((uintptr_t)os, obj, (uint64_t)lvl, blkid)); +} + +#define DTRACE_SET_STATE(db, why) \ + DTRACE_PROBE2(dbuf__state_change, dmu_buf_impl_t *, db, \ + const char *, why) + +#define DBUF_EQUAL(dbuf, os, obj, level, blkid) \ + ((dbuf)->db.db_object == (obj) && \ + (dbuf)->db_objset == (os) && \ + (dbuf)->db_level == (level) && \ + (dbuf)->db_blkid == (blkid)) + +dmu_buf_impl_t * +dbuf_find(objset_t *os, uint64_t obj, uint8_t level, uint64_t blkid) +{ + dbuf_hash_table_t *h = &dbuf_hash_table; + uint64_t hv; + uint64_t idx; + dmu_buf_impl_t *db; + + hv = dbuf_hash(os, obj, level, blkid); + idx = hv & h->hash_table_mask; + + mutex_enter(DBUF_HASH_MUTEX(h, idx)); + for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) { + if (DBUF_EQUAL(db, os, obj, level, blkid)) { + mutex_enter(&db->db_mtx); + if (db->db_state != DB_EVICTING) { + mutex_exit(DBUF_HASH_MUTEX(h, idx)); + return (db); + } + mutex_exit(&db->db_mtx); + } + } + mutex_exit(DBUF_HASH_MUTEX(h, idx)); + return (NULL); +} + +static dmu_buf_impl_t * +dbuf_find_bonus(objset_t *os, uint64_t object) +{ + dnode_t *dn; + dmu_buf_impl_t *db = NULL; + + if (dnode_hold(os, object, FTAG, &dn) == 0) { + rw_enter(&dn->dn_struct_rwlock, RW_READER); + if (dn->dn_bonus != NULL) { + db = dn->dn_bonus; + mutex_enter(&db->db_mtx); + } + rw_exit(&dn->dn_struct_rwlock); + dnode_rele(dn, FTAG); + } + return (db); +} + +/* + * Insert an entry into the hash table. If there is already an element + * equal to elem in the hash table, then the already existing element + * will be returned and the new element will not be inserted. + * Otherwise returns NULL. + */ +static dmu_buf_impl_t * +dbuf_hash_insert(dmu_buf_impl_t *db) +{ + dbuf_hash_table_t *h = &dbuf_hash_table; + objset_t *os = db->db_objset; + uint64_t obj = db->db.db_object; + int level = db->db_level; + uint64_t blkid, hv, idx; + dmu_buf_impl_t *dbf; + uint32_t i; + + blkid = db->db_blkid; + hv = dbuf_hash(os, obj, level, blkid); + idx = hv & h->hash_table_mask; + + mutex_enter(DBUF_HASH_MUTEX(h, idx)); + for (dbf = h->hash_table[idx], i = 0; dbf != NULL; + dbf = dbf->db_hash_next, i++) { + if (DBUF_EQUAL(dbf, os, obj, level, blkid)) { + mutex_enter(&dbf->db_mtx); + if (dbf->db_state != DB_EVICTING) { + mutex_exit(DBUF_HASH_MUTEX(h, idx)); + return (dbf); + } + mutex_exit(&dbf->db_mtx); + } + } + + if (i > 0) { + DBUF_STAT_BUMP(hash_collisions); + if (i == 1) + DBUF_STAT_BUMP(hash_chains); + + DBUF_STAT_MAX(hash_chain_max, i); + } + + mutex_enter(&db->db_mtx); + db->db_hash_next = h->hash_table[idx]; + h->hash_table[idx] = db; + mutex_exit(DBUF_HASH_MUTEX(h, idx)); + atomic_inc_64(&dbuf_hash_count); + DBUF_STAT_MAX(hash_elements_max, dbuf_hash_count); + + return (NULL); +} + +/* + * This returns whether this dbuf should be stored in the metadata cache, which + * is based on whether it's from one of the dnode types that store data related + * to traversing dataset hierarchies. + */ +static boolean_t +dbuf_include_in_metadata_cache(dmu_buf_impl_t *db) +{ + DB_DNODE_ENTER(db); + dmu_object_type_t type = DB_DNODE(db)->dn_type; + DB_DNODE_EXIT(db); + + /* Check if this dbuf is one of the types we care about */ + if (DMU_OT_IS_METADATA_CACHED(type)) { + /* If we hit this, then we set something up wrong in dmu_ot */ + ASSERT(DMU_OT_IS_METADATA(type)); + + /* + * Sanity check for small-memory systems: don't allocate too + * much memory for this purpose. + */ + if (zfs_refcount_count( + &dbuf_caches[DB_DBUF_METADATA_CACHE].size) > + dbuf_metadata_cache_target_bytes()) { + DBUF_STAT_BUMP(metadata_cache_overflow); + return (B_FALSE); + } + + return (B_TRUE); + } + + return (B_FALSE); +} + +/* + * Remove an entry from the hash table. It must be in the EVICTING state. + */ +static void +dbuf_hash_remove(dmu_buf_impl_t *db) +{ + dbuf_hash_table_t *h = &dbuf_hash_table; + uint64_t hv, idx; + dmu_buf_impl_t *dbf, **dbp; + + hv = dbuf_hash(db->db_objset, db->db.db_object, + db->db_level, db->db_blkid); + idx = hv & h->hash_table_mask; + + /* + * We mustn't hold db_mtx to maintain lock ordering: + * DBUF_HASH_MUTEX > db_mtx. + */ + ASSERT(zfs_refcount_is_zero(&db->db_holds)); + ASSERT(db->db_state == DB_EVICTING); + ASSERT(!MUTEX_HELD(&db->db_mtx)); + + mutex_enter(DBUF_HASH_MUTEX(h, idx)); + dbp = &h->hash_table[idx]; + while ((dbf = *dbp) != db) { + dbp = &dbf->db_hash_next; + ASSERT(dbf != NULL); + } + *dbp = db->db_hash_next; + db->db_hash_next = NULL; + if (h->hash_table[idx] && + h->hash_table[idx]->db_hash_next == NULL) + DBUF_STAT_BUMPDOWN(hash_chains); + mutex_exit(DBUF_HASH_MUTEX(h, idx)); + atomic_dec_64(&dbuf_hash_count); +} + +typedef enum { + DBVU_EVICTING, + DBVU_NOT_EVICTING +} dbvu_verify_type_t; + +static void +dbuf_verify_user(dmu_buf_impl_t *db, dbvu_verify_type_t verify_type) +{ +#ifdef ZFS_DEBUG + int64_t holds; + + if (db->db_user == NULL) + return; + + /* Only data blocks support the attachment of user data. */ + ASSERT(db->db_level == 0); + + /* Clients must resolve a dbuf before attaching user data. */ + ASSERT(db->db.db_data != NULL); + ASSERT3U(db->db_state, ==, DB_CACHED); + + holds = zfs_refcount_count(&db->db_holds); + if (verify_type == DBVU_EVICTING) { + /* + * Immediate eviction occurs when holds == dirtycnt. + * For normal eviction buffers, holds is zero on + * eviction, except when dbuf_fix_old_data() calls + * dbuf_clear_data(). However, the hold count can grow + * during eviction even though db_mtx is held (see + * dmu_bonus_hold() for an example), so we can only + * test the generic invariant that holds >= dirtycnt. + */ + ASSERT3U(holds, >=, db->db_dirtycnt); + } else { + if (db->db_user_immediate_evict == TRUE) + ASSERT3U(holds, >=, db->db_dirtycnt); + else + ASSERT3U(holds, >, 0); + } +#endif +} + +static void +dbuf_evict_user(dmu_buf_impl_t *db) +{ + dmu_buf_user_t *dbu = db->db_user; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + + if (dbu == NULL) + return; + + dbuf_verify_user(db, DBVU_EVICTING); + db->db_user = NULL; + +#ifdef ZFS_DEBUG + if (dbu->dbu_clear_on_evict_dbufp != NULL) + *dbu->dbu_clear_on_evict_dbufp = NULL; +#endif + + /* + * There are two eviction callbacks - one that we call synchronously + * and one that we invoke via a taskq. The async one is useful for + * avoiding lock order reversals and limiting stack depth. + * + * Note that if we have a sync callback but no async callback, + * it's likely that the sync callback will free the structure + * containing the dbu. In that case we need to take care to not + * dereference dbu after calling the sync evict func. + */ + boolean_t has_async = (dbu->dbu_evict_func_async != NULL); + + if (dbu->dbu_evict_func_sync != NULL) + dbu->dbu_evict_func_sync(dbu); + + if (has_async) { + taskq_dispatch_ent(dbu_evict_taskq, dbu->dbu_evict_func_async, + dbu, 0, &dbu->dbu_tqent); + } +} + +boolean_t +dbuf_is_metadata(dmu_buf_impl_t *db) +{ + /* + * Consider indirect blocks and spill blocks to be meta data. + */ + if (db->db_level > 0 || db->db_blkid == DMU_SPILL_BLKID) { + return (B_TRUE); + } else { + boolean_t is_metadata; + + DB_DNODE_ENTER(db); + is_metadata = DMU_OT_IS_METADATA(DB_DNODE(db)->dn_type); + DB_DNODE_EXIT(db); + + return (is_metadata); + } +} + + +/* + * This function *must* return indices evenly distributed between all + * sublists of the multilist. This is needed due to how the dbuf eviction + * code is laid out; dbuf_evict_thread() assumes dbufs are evenly + * distributed between all sublists and uses this assumption when + * deciding which sublist to evict from and how much to evict from it. + */ +static unsigned int +dbuf_cache_multilist_index_func(multilist_t *ml, void *obj) +{ + dmu_buf_impl_t *db = obj; + + /* + * The assumption here, is the hash value for a given + * dmu_buf_impl_t will remain constant throughout it's lifetime + * (i.e. it's objset, object, level and blkid fields don't change). + * Thus, we don't need to store the dbuf's sublist index + * on insertion, as this index can be recalculated on removal. + * + * Also, the low order bits of the hash value are thought to be + * distributed evenly. Otherwise, in the case that the multilist + * has a power of two number of sublists, each sublists' usage + * would not be evenly distributed. + */ + return (dbuf_hash(db->db_objset, db->db.db_object, + db->db_level, db->db_blkid) % + multilist_get_num_sublists(ml)); +} + +/* + * The target size of the dbuf cache can grow with the ARC target, + * unless limited by the tunable dbuf_cache_max_bytes. + */ +static inline unsigned long +dbuf_cache_target_bytes(void) +{ + return (MIN(dbuf_cache_max_bytes, + arc_target_bytes() >> dbuf_cache_shift)); +} + +/* + * The target size of the dbuf metadata cache can grow with the ARC target, + * unless limited by the tunable dbuf_metadata_cache_max_bytes. + */ +static inline unsigned long +dbuf_metadata_cache_target_bytes(void) +{ + return (MIN(dbuf_metadata_cache_max_bytes, + arc_target_bytes() >> dbuf_metadata_cache_shift)); +} + +static inline uint64_t +dbuf_cache_hiwater_bytes(void) +{ + uint64_t dbuf_cache_target = dbuf_cache_target_bytes(); + return (dbuf_cache_target + + (dbuf_cache_target * dbuf_cache_hiwater_pct) / 100); +} + +static inline uint64_t +dbuf_cache_lowater_bytes(void) +{ + uint64_t dbuf_cache_target = dbuf_cache_target_bytes(); + return (dbuf_cache_target - + (dbuf_cache_target * dbuf_cache_lowater_pct) / 100); +} + +static inline boolean_t +dbuf_cache_above_lowater(void) +{ + return (zfs_refcount_count(&dbuf_caches[DB_DBUF_CACHE].size) > + dbuf_cache_lowater_bytes()); +} + +/* + * Evict the oldest eligible dbuf from the dbuf cache. + */ +static void +dbuf_evict_one(void) +{ + int idx = multilist_get_random_index(dbuf_caches[DB_DBUF_CACHE].cache); + multilist_sublist_t *mls = multilist_sublist_lock( + dbuf_caches[DB_DBUF_CACHE].cache, idx); + + ASSERT(!MUTEX_HELD(&dbuf_evict_lock)); + + dmu_buf_impl_t *db = multilist_sublist_tail(mls); + while (db != NULL && mutex_tryenter(&db->db_mtx) == 0) { + db = multilist_sublist_prev(mls, db); + } + + DTRACE_PROBE2(dbuf__evict__one, dmu_buf_impl_t *, db, + multilist_sublist_t *, mls); + + if (db != NULL) { + multilist_sublist_remove(mls, db); + multilist_sublist_unlock(mls); + (void) zfs_refcount_remove_many( + &dbuf_caches[DB_DBUF_CACHE].size, db->db.db_size, db); + DBUF_STAT_BUMPDOWN(cache_levels[db->db_level]); + DBUF_STAT_BUMPDOWN(cache_count); + DBUF_STAT_DECR(cache_levels_bytes[db->db_level], + db->db.db_size); + ASSERT3U(db->db_caching_status, ==, DB_DBUF_CACHE); + db->db_caching_status = DB_NO_CACHE; + dbuf_destroy(db); + DBUF_STAT_BUMP(cache_total_evicts); + } else { + multilist_sublist_unlock(mls); + } +} + +/* + * The dbuf evict thread is responsible for aging out dbufs from the + * cache. Once the cache has reached it's maximum size, dbufs are removed + * and destroyed. The eviction thread will continue running until the size + * of the dbuf cache is at or below the maximum size. Once the dbuf is aged + * out of the cache it is destroyed and becomes eligible for arc eviction. + */ +/* ARGSUSED */ +static void +dbuf_evict_thread(void *unused) +{ + callb_cpr_t cpr; + + CALLB_CPR_INIT(&cpr, &dbuf_evict_lock, callb_generic_cpr, FTAG); + + mutex_enter(&dbuf_evict_lock); + while (!dbuf_evict_thread_exit) { + while (!dbuf_cache_above_lowater() && !dbuf_evict_thread_exit) { + CALLB_CPR_SAFE_BEGIN(&cpr); + (void) cv_timedwait_sig_hires(&dbuf_evict_cv, + &dbuf_evict_lock, SEC2NSEC(1), MSEC2NSEC(1), 0); + CALLB_CPR_SAFE_END(&cpr, &dbuf_evict_lock); + } + mutex_exit(&dbuf_evict_lock); + + /* + * Keep evicting as long as we're above the low water mark + * for the cache. We do this without holding the locks to + * minimize lock contention. + */ + while (dbuf_cache_above_lowater() && !dbuf_evict_thread_exit) { + dbuf_evict_one(); + } + + mutex_enter(&dbuf_evict_lock); + } + + dbuf_evict_thread_exit = B_FALSE; + cv_broadcast(&dbuf_evict_cv); + CALLB_CPR_EXIT(&cpr); /* drops dbuf_evict_lock */ + thread_exit(); +} + +/* + * Wake up the dbuf eviction thread if the dbuf cache is at its max size. + * If the dbuf cache is at its high water mark, then evict a dbuf from the + * dbuf cache using the callers context. + */ +static void +dbuf_evict_notify(uint64_t size) +{ + /* + * We check if we should evict without holding the dbuf_evict_lock, + * because it's OK to occasionally make the wrong decision here, + * and grabbing the lock results in massive lock contention. + */ + if (size > dbuf_cache_target_bytes()) { + if (size > dbuf_cache_hiwater_bytes()) + dbuf_evict_one(); + cv_signal(&dbuf_evict_cv); + } +} + +static int +dbuf_kstat_update(kstat_t *ksp, int rw) +{ + dbuf_stats_t *ds = ksp->ks_data; + + if (rw == KSTAT_WRITE) { + return (SET_ERROR(EACCES)); + } else { + ds->metadata_cache_size_bytes.value.ui64 = zfs_refcount_count( + &dbuf_caches[DB_DBUF_METADATA_CACHE].size); + ds->cache_size_bytes.value.ui64 = + zfs_refcount_count(&dbuf_caches[DB_DBUF_CACHE].size); + ds->cache_target_bytes.value.ui64 = dbuf_cache_target_bytes(); + ds->cache_hiwater_bytes.value.ui64 = dbuf_cache_hiwater_bytes(); + ds->cache_lowater_bytes.value.ui64 = dbuf_cache_lowater_bytes(); + ds->hash_elements.value.ui64 = dbuf_hash_count; + } + + return (0); +} + +void +dbuf_init(void) +{ + uint64_t hsize = 1ULL << 16; + dbuf_hash_table_t *h = &dbuf_hash_table; + int i; + + /* + * The hash table is big enough to fill all of physical memory + * with an average block size of zfs_arc_average_blocksize (default 8K). + * By default, the table will take up + * totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers). + */ + while (hsize * zfs_arc_average_blocksize < physmem * PAGESIZE) + hsize <<= 1; + +retry: + h->hash_table_mask = hsize - 1; +#if defined(_KERNEL) + /* + * Large allocations which do not require contiguous pages + * should be using vmem_alloc() in the linux kernel + */ + h->hash_table = vmem_zalloc(hsize * sizeof (void *), KM_SLEEP); +#else + h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP); +#endif + if (h->hash_table == NULL) { + /* XXX - we should really return an error instead of assert */ + ASSERT(hsize > (1ULL << 10)); + hsize >>= 1; + goto retry; + } + + dbuf_kmem_cache = kmem_cache_create("dmu_buf_impl_t", + sizeof (dmu_buf_impl_t), + 0, dbuf_cons, dbuf_dest, NULL, NULL, NULL, 0); + + for (i = 0; i < DBUF_MUTEXES; i++) + mutex_init(&h->hash_mutexes[i], NULL, MUTEX_DEFAULT, NULL); + + dbuf_stats_init(h); + + /* + * All entries are queued via taskq_dispatch_ent(), so min/maxalloc + * configuration is not required. + */ + dbu_evict_taskq = taskq_create("dbu_evict", 1, defclsyspri, 0, 0, 0); + + for (dbuf_cached_state_t dcs = 0; dcs < DB_CACHE_MAX; dcs++) { + dbuf_caches[dcs].cache = + multilist_create(sizeof (dmu_buf_impl_t), + offsetof(dmu_buf_impl_t, db_cache_link), + dbuf_cache_multilist_index_func); + zfs_refcount_create(&dbuf_caches[dcs].size); + } + + dbuf_evict_thread_exit = B_FALSE; + mutex_init(&dbuf_evict_lock, NULL, MUTEX_DEFAULT, NULL); + cv_init(&dbuf_evict_cv, NULL, CV_DEFAULT, NULL); + dbuf_cache_evict_thread = thread_create(NULL, 0, dbuf_evict_thread, + NULL, 0, &p0, TS_RUN, minclsyspri); + + dbuf_ksp = kstat_create("zfs", 0, "dbufstats", "misc", + KSTAT_TYPE_NAMED, sizeof (dbuf_stats) / sizeof (kstat_named_t), + KSTAT_FLAG_VIRTUAL); + if (dbuf_ksp != NULL) { + for (i = 0; i < DN_MAX_LEVELS; i++) { + snprintf(dbuf_stats.cache_levels[i].name, + KSTAT_STRLEN, "cache_level_%d", i); + dbuf_stats.cache_levels[i].data_type = + KSTAT_DATA_UINT64; + snprintf(dbuf_stats.cache_levels_bytes[i].name, + KSTAT_STRLEN, "cache_level_%d_bytes", i); + dbuf_stats.cache_levels_bytes[i].data_type = + KSTAT_DATA_UINT64; + } + dbuf_ksp->ks_data = &dbuf_stats; + dbuf_ksp->ks_update = dbuf_kstat_update; + kstat_install(dbuf_ksp); + } +} + +void +dbuf_fini(void) +{ + dbuf_hash_table_t *h = &dbuf_hash_table; + int i; + + dbuf_stats_destroy(); + + for (i = 0; i < DBUF_MUTEXES; i++) + mutex_destroy(&h->hash_mutexes[i]); +#if defined(_KERNEL) + /* + * Large allocations which do not require contiguous pages + * should be using vmem_free() in the linux kernel + */ + vmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); +#else + kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *)); +#endif + kmem_cache_destroy(dbuf_kmem_cache); + taskq_destroy(dbu_evict_taskq); + + mutex_enter(&dbuf_evict_lock); + dbuf_evict_thread_exit = B_TRUE; + while (dbuf_evict_thread_exit) { + cv_signal(&dbuf_evict_cv); + cv_wait(&dbuf_evict_cv, &dbuf_evict_lock); + } + mutex_exit(&dbuf_evict_lock); + + mutex_destroy(&dbuf_evict_lock); + cv_destroy(&dbuf_evict_cv); + + for (dbuf_cached_state_t dcs = 0; dcs < DB_CACHE_MAX; dcs++) { + zfs_refcount_destroy(&dbuf_caches[dcs].size); + multilist_destroy(dbuf_caches[dcs].cache); + } + + if (dbuf_ksp != NULL) { + kstat_delete(dbuf_ksp); + dbuf_ksp = NULL; + } +} + +/* + * Other stuff. + */ + +#ifdef ZFS_DEBUG +static void +dbuf_verify(dmu_buf_impl_t *db) +{ + dnode_t *dn; + dbuf_dirty_record_t *dr; + uint32_t txg_prev; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + + if (!(zfs_flags & ZFS_DEBUG_DBUF_VERIFY)) + return; + + ASSERT(db->db_objset != NULL); + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + if (dn == NULL) { + ASSERT(db->db_parent == NULL); + ASSERT(db->db_blkptr == NULL); + } else { + ASSERT3U(db->db.db_object, ==, dn->dn_object); + ASSERT3P(db->db_objset, ==, dn->dn_objset); + ASSERT3U(db->db_level, <, dn->dn_nlevels); + ASSERT(db->db_blkid == DMU_BONUS_BLKID || + db->db_blkid == DMU_SPILL_BLKID || + !avl_is_empty(&dn->dn_dbufs)); + } + if (db->db_blkid == DMU_BONUS_BLKID) { + ASSERT(dn != NULL); + ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); + ASSERT3U(db->db.db_offset, ==, DMU_BONUS_BLKID); + } else if (db->db_blkid == DMU_SPILL_BLKID) { + ASSERT(dn != NULL); + ASSERT0(db->db.db_offset); + } else { + ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size); + } + + if ((dr = list_head(&db->db_dirty_records)) != NULL) { + ASSERT(dr->dr_dbuf == db); + txg_prev = dr->dr_txg; + for (dr = list_next(&db->db_dirty_records, dr); dr != NULL; + dr = list_next(&db->db_dirty_records, dr)) { + ASSERT(dr->dr_dbuf == db); + ASSERT(txg_prev > dr->dr_txg); + txg_prev = dr->dr_txg; + } + } + + /* + * We can't assert that db_size matches dn_datablksz because it + * can be momentarily different when another thread is doing + * dnode_set_blksz(). + */ + if (db->db_level == 0 && db->db.db_object == DMU_META_DNODE_OBJECT) { + dr = db->db_data_pending; + /* + * It should only be modified in syncing context, so + * make sure we only have one copy of the data. + */ + ASSERT(dr == NULL || dr->dt.dl.dr_data == db->db_buf); + } + + /* verify db->db_blkptr */ + if (db->db_blkptr) { + if (db->db_parent == dn->dn_dbuf) { + /* db is pointed to by the dnode */ + /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */ + if (DMU_OBJECT_IS_SPECIAL(db->db.db_object)) + ASSERT(db->db_parent == NULL); + else + ASSERT(db->db_parent != NULL); + if (db->db_blkid != DMU_SPILL_BLKID) + ASSERT3P(db->db_blkptr, ==, + &dn->dn_phys->dn_blkptr[db->db_blkid]); + } else { + /* db is pointed to by an indirect block */ + int epb __maybe_unused = db->db_parent->db.db_size >> + SPA_BLKPTRSHIFT; + ASSERT3U(db->db_parent->db_level, ==, db->db_level+1); + ASSERT3U(db->db_parent->db.db_object, ==, + db->db.db_object); + /* + * dnode_grow_indblksz() can make this fail if we don't + * have the parent's rwlock. XXX indblksz no longer + * grows. safe to do this now? + */ + if (RW_LOCK_HELD(&db->db_parent->db_rwlock)) { + ASSERT3P(db->db_blkptr, ==, + ((blkptr_t *)db->db_parent->db.db_data + + db->db_blkid % epb)); + } + } + } + if ((db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr)) && + (db->db_buf == NULL || db->db_buf->b_data) && + db->db.db_data && db->db_blkid != DMU_BONUS_BLKID && + db->db_state != DB_FILL && !dn->dn_free_txg) { + /* + * If the blkptr isn't set but they have nonzero data, + * it had better be dirty, otherwise we'll lose that + * data when we evict this buffer. + * + * There is an exception to this rule for indirect blocks; in + * this case, if the indirect block is a hole, we fill in a few + * fields on each of the child blocks (importantly, birth time) + * to prevent hole birth times from being lost when you + * partially fill in a hole. + */ + if (db->db_dirtycnt == 0) { + if (db->db_level == 0) { + uint64_t *buf = db->db.db_data; + int i; + + for (i = 0; i < db->db.db_size >> 3; i++) { + ASSERT(buf[i] == 0); + } + } else { + blkptr_t *bps = db->db.db_data; + ASSERT3U(1 << DB_DNODE(db)->dn_indblkshift, ==, + db->db.db_size); + /* + * We want to verify that all the blkptrs in the + * indirect block are holes, but we may have + * automatically set up a few fields for them. + * We iterate through each blkptr and verify + * they only have those fields set. + */ + for (int i = 0; + i < db->db.db_size / sizeof (blkptr_t); + i++) { + blkptr_t *bp = &bps[i]; + ASSERT(ZIO_CHECKSUM_IS_ZERO( + &bp->blk_cksum)); + ASSERT( + DVA_IS_EMPTY(&bp->blk_dva[0]) && + DVA_IS_EMPTY(&bp->blk_dva[1]) && + DVA_IS_EMPTY(&bp->blk_dva[2])); + ASSERT0(bp->blk_fill); + ASSERT0(bp->blk_pad[0]); + ASSERT0(bp->blk_pad[1]); + ASSERT(!BP_IS_EMBEDDED(bp)); + ASSERT(BP_IS_HOLE(bp)); + ASSERT0(bp->blk_phys_birth); + } + } + } + } + DB_DNODE_EXIT(db); +} +#endif + +static void +dbuf_clear_data(dmu_buf_impl_t *db) +{ + ASSERT(MUTEX_HELD(&db->db_mtx)); + dbuf_evict_user(db); + ASSERT3P(db->db_buf, ==, NULL); + db->db.db_data = NULL; + if (db->db_state != DB_NOFILL) { + db->db_state = DB_UNCACHED; + DTRACE_SET_STATE(db, "clear data"); + } +} + +static void +dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf) +{ + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(buf != NULL); + + db->db_buf = buf; + ASSERT(buf->b_data != NULL); + db->db.db_data = buf->b_data; +} + +static arc_buf_t * +dbuf_alloc_arcbuf_from_arcbuf(dmu_buf_impl_t *db, arc_buf_t *data) +{ + objset_t *os = db->db_objset; + spa_t *spa = os->os_spa; + arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); + enum zio_compress compress_type; + uint8_t complevel; + int psize, lsize; + + psize = arc_buf_size(data); + lsize = arc_buf_lsize(data); + compress_type = arc_get_compression(data); + complevel = arc_get_complevel(data); + + if (arc_is_encrypted(data)) { + boolean_t byteorder; + uint8_t salt[ZIO_DATA_SALT_LEN]; + uint8_t iv[ZIO_DATA_IV_LEN]; + uint8_t mac[ZIO_DATA_MAC_LEN]; + dnode_t *dn = DB_DNODE(db); + + arc_get_raw_params(data, &byteorder, salt, iv, mac); + data = arc_alloc_raw_buf(spa, db, dmu_objset_id(os), + byteorder, salt, iv, mac, dn->dn_type, psize, lsize, + compress_type, complevel); + } else if (compress_type != ZIO_COMPRESS_OFF) { + ASSERT3U(type, ==, ARC_BUFC_DATA); + data = arc_alloc_compressed_buf(spa, db, + psize, lsize, compress_type, complevel); + } else { + data = arc_alloc_buf(spa, db, type, psize); + } + return (data); +} + +static arc_buf_t * +dbuf_alloc_arcbuf(dmu_buf_impl_t *db) +{ + spa_t *spa = db->db_objset->os_spa; + + return (arc_alloc_buf(spa, db, DBUF_GET_BUFC_TYPE(db), db->db.db_size)); +} + +/* + * Loan out an arc_buf for read. Return the loaned arc_buf. + */ +arc_buf_t * +dbuf_loan_arcbuf(dmu_buf_impl_t *db) +{ + arc_buf_t *abuf; + + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + mutex_enter(&db->db_mtx); + if (arc_released(db->db_buf) || zfs_refcount_count(&db->db_holds) > 1) { + int blksz = db->db.db_size; + spa_t *spa = db->db_objset->os_spa; + + mutex_exit(&db->db_mtx); + abuf = arc_loan_buf(spa, B_FALSE, blksz); + bcopy(db->db.db_data, abuf->b_data, blksz); + } else { + abuf = db->db_buf; + arc_loan_inuse_buf(abuf, db); + db->db_buf = NULL; + dbuf_clear_data(db); + mutex_exit(&db->db_mtx); + } + return (abuf); +} + +/* + * Calculate which level n block references the data at the level 0 offset + * provided. + */ +uint64_t +dbuf_whichblock(const dnode_t *dn, const int64_t level, const uint64_t offset) +{ + if (dn->dn_datablkshift != 0 && dn->dn_indblkshift != 0) { + /* + * The level n blkid is equal to the level 0 blkid divided by + * the number of level 0s in a level n block. + * + * The level 0 blkid is offset >> datablkshift = + * offset / 2^datablkshift. + * + * The number of level 0s in a level n is the number of block + * pointers in an indirect block, raised to the power of level. + * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level = + * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)). + * + * Thus, the level n blkid is: offset / + * ((2^datablkshift)*(2^(level*(indblkshift-SPA_BLKPTRSHIFT)))) + * = offset / 2^(datablkshift + level * + * (indblkshift - SPA_BLKPTRSHIFT)) + * = offset >> (datablkshift + level * + * (indblkshift - SPA_BLKPTRSHIFT)) + */ + + const unsigned exp = dn->dn_datablkshift + + level * (dn->dn_indblkshift - SPA_BLKPTRSHIFT); + + if (exp >= 8 * sizeof (offset)) { + /* This only happens on the highest indirection level */ + ASSERT3U(level, ==, dn->dn_nlevels - 1); + return (0); + } + + ASSERT3U(exp, <, 8 * sizeof (offset)); + + return (offset >> exp); + } else { + ASSERT3U(offset, <, dn->dn_datablksz); + return (0); + } +} + +/* + * This function is used to lock the parent of the provided dbuf. This should be + * used when modifying or reading db_blkptr. + */ +db_lock_type_t +dmu_buf_lock_parent(dmu_buf_impl_t *db, krw_t rw, void *tag) +{ + enum db_lock_type ret = DLT_NONE; + if (db->db_parent != NULL) { + rw_enter(&db->db_parent->db_rwlock, rw); + ret = DLT_PARENT; + } else if (dmu_objset_ds(db->db_objset) != NULL) { + rrw_enter(&dmu_objset_ds(db->db_objset)->ds_bp_rwlock, rw, + tag); + ret = DLT_OBJSET; + } + /* + * We only return a DLT_NONE lock when it's the top-most indirect block + * of the meta-dnode of the MOS. + */ + return (ret); +} + +/* + * We need to pass the lock type in because it's possible that the block will + * move from being the topmost indirect block in a dnode (and thus, have no + * parent) to not the top-most via an indirection increase. This would cause a + * panic if we didn't pass the lock type in. + */ +void +dmu_buf_unlock_parent(dmu_buf_impl_t *db, db_lock_type_t type, void *tag) +{ + if (type == DLT_PARENT) + rw_exit(&db->db_parent->db_rwlock); + else if (type == DLT_OBJSET) + rrw_exit(&dmu_objset_ds(db->db_objset)->ds_bp_rwlock, tag); +} + +static void +dbuf_read_done(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, + arc_buf_t *buf, void *vdb) +{ + dmu_buf_impl_t *db = vdb; + + mutex_enter(&db->db_mtx); + ASSERT3U(db->db_state, ==, DB_READ); + /* + * All reads are synchronous, so we must have a hold on the dbuf + */ + ASSERT(zfs_refcount_count(&db->db_holds) > 0); + ASSERT(db->db_buf == NULL); + ASSERT(db->db.db_data == NULL); + if (buf == NULL) { + /* i/o error */ + ASSERT(zio == NULL || zio->io_error != 0); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT3P(db->db_buf, ==, NULL); + db->db_state = DB_UNCACHED; + DTRACE_SET_STATE(db, "i/o error"); + } else if (db->db_level == 0 && db->db_freed_in_flight) { + /* freed in flight */ + ASSERT(zio == NULL || zio->io_error == 0); + arc_release(buf, db); + bzero(buf->b_data, db->db.db_size); + arc_buf_freeze(buf); + db->db_freed_in_flight = FALSE; + dbuf_set_data(db, buf); + db->db_state = DB_CACHED; + DTRACE_SET_STATE(db, "freed in flight"); + } else { + /* success */ + ASSERT(zio == NULL || zio->io_error == 0); + dbuf_set_data(db, buf); + db->db_state = DB_CACHED; + DTRACE_SET_STATE(db, "successful read"); + } + cv_broadcast(&db->db_changed); + dbuf_rele_and_unlock(db, NULL, B_FALSE); +} + +/* + * Shortcut for performing reads on bonus dbufs. Returns + * an error if we fail to verify the dnode associated with + * a decrypted block. Otherwise success. + */ +static int +dbuf_read_bonus(dmu_buf_impl_t *db, dnode_t *dn, uint32_t flags) +{ + int bonuslen, max_bonuslen, err; + + err = dbuf_read_verify_dnode_crypt(db, flags); + if (err) + return (err); + + bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen); + max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(DB_DNODE_HELD(db)); + ASSERT3U(bonuslen, <=, db->db.db_size); + db->db.db_data = kmem_alloc(max_bonuslen, KM_SLEEP); + arc_space_consume(max_bonuslen, ARC_SPACE_BONUS); + if (bonuslen < max_bonuslen) + bzero(db->db.db_data, max_bonuslen); + if (bonuslen) + bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen); + db->db_state = DB_CACHED; + DTRACE_SET_STATE(db, "bonus buffer filled"); + return (0); +} + +static void +dbuf_handle_indirect_hole(dmu_buf_impl_t *db, dnode_t *dn) +{ + blkptr_t *bps = db->db.db_data; + uint32_t indbs = 1ULL << dn->dn_indblkshift; + int n_bps = indbs >> SPA_BLKPTRSHIFT; + + for (int i = 0; i < n_bps; i++) { + blkptr_t *bp = &bps[i]; + + ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, indbs); + BP_SET_LSIZE(bp, BP_GET_LEVEL(db->db_blkptr) == 1 ? + dn->dn_datablksz : BP_GET_LSIZE(db->db_blkptr)); + BP_SET_TYPE(bp, BP_GET_TYPE(db->db_blkptr)); + BP_SET_LEVEL(bp, BP_GET_LEVEL(db->db_blkptr) - 1); + BP_SET_BIRTH(bp, db->db_blkptr->blk_birth, 0); + } +} + +/* + * Handle reads on dbufs that are holes, if necessary. This function + * requires that the dbuf's mutex is held. Returns success (0) if action + * was taken, ENOENT if no action was taken. + */ +static int +dbuf_read_hole(dmu_buf_impl_t *db, dnode_t *dn, uint32_t flags) +{ + ASSERT(MUTEX_HELD(&db->db_mtx)); + + int is_hole = db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr); + /* + * For level 0 blocks only, if the above check fails: + * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync() + * processes the delete record and clears the bp while we are waiting + * for the dn_mtx (resulting in a "no" from block_freed). + */ + if (!is_hole && db->db_level == 0) { + is_hole = dnode_block_freed(dn, db->db_blkid) || + BP_IS_HOLE(db->db_blkptr); + } + + if (is_hole) { + dbuf_set_data(db, dbuf_alloc_arcbuf(db)); + bzero(db->db.db_data, db->db.db_size); + + if (db->db_blkptr != NULL && db->db_level > 0 && + BP_IS_HOLE(db->db_blkptr) && + db->db_blkptr->blk_birth != 0) { + dbuf_handle_indirect_hole(db, dn); + } + db->db_state = DB_CACHED; + DTRACE_SET_STATE(db, "hole read satisfied"); + return (0); + } + return (ENOENT); +} + +/* + * This function ensures that, when doing a decrypting read of a block, + * we make sure we have decrypted the dnode associated with it. We must do + * this so that we ensure we are fully authenticating the checksum-of-MACs + * tree from the root of the objset down to this block. Indirect blocks are + * always verified against their secure checksum-of-MACs assuming that the + * dnode containing them is correct. Now that we are doing a decrypting read, + * we can be sure that the key is loaded and verify that assumption. This is + * especially important considering that we always read encrypted dnode + * blocks as raw data (without verifying their MACs) to start, and + * decrypt / authenticate them when we need to read an encrypted bonus buffer. + */ +static int +dbuf_read_verify_dnode_crypt(dmu_buf_impl_t *db, uint32_t flags) +{ + int err = 0; + objset_t *os = db->db_objset; + arc_buf_t *dnode_abuf; + dnode_t *dn; + zbookmark_phys_t zb; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + + if (!os->os_encrypted || os->os_raw_receive || + (flags & DB_RF_NO_DECRYPT) != 0) + return (0); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + dnode_abuf = (dn->dn_dbuf != NULL) ? dn->dn_dbuf->db_buf : NULL; + + if (dnode_abuf == NULL || !arc_is_encrypted(dnode_abuf)) { + DB_DNODE_EXIT(db); + return (0); + } + + SET_BOOKMARK(&zb, dmu_objset_id(os), + DMU_META_DNODE_OBJECT, 0, dn->dn_dbuf->db_blkid); + err = arc_untransform(dnode_abuf, os->os_spa, &zb, B_TRUE); + + /* + * An error code of EACCES tells us that the key is still not + * available. This is ok if we are only reading authenticated + * (and therefore non-encrypted) blocks. + */ + if (err == EACCES && ((db->db_blkid != DMU_BONUS_BLKID && + !DMU_OT_IS_ENCRYPTED(dn->dn_type)) || + (db->db_blkid == DMU_BONUS_BLKID && + !DMU_OT_IS_ENCRYPTED(dn->dn_bonustype)))) + err = 0; + + DB_DNODE_EXIT(db); + + return (err); +} + +/* + * Drops db_mtx and the parent lock specified by dblt and tag before + * returning. + */ +static int +dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags, + db_lock_type_t dblt, void *tag) +{ + dnode_t *dn; + zbookmark_phys_t zb; + uint32_t aflags = ARC_FLAG_NOWAIT; + int err, zio_flags; + boolean_t bonus_read; + + err = zio_flags = 0; + bonus_read = B_FALSE; + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(db->db_state == DB_UNCACHED); + ASSERT(db->db_buf == NULL); + ASSERT(db->db_parent == NULL || + RW_LOCK_HELD(&db->db_parent->db_rwlock)); + + if (db->db_blkid == DMU_BONUS_BLKID) { + err = dbuf_read_bonus(db, dn, flags); + goto early_unlock; + } + + err = dbuf_read_hole(db, dn, flags); + if (err == 0) + goto early_unlock; + + /* + * Any attempt to read a redacted block should result in an error. This + * will never happen under normal conditions, but can be useful for + * debugging purposes. + */ + if (BP_IS_REDACTED(db->db_blkptr)) { + ASSERT(dsl_dataset_feature_is_active( + db->db_objset->os_dsl_dataset, + SPA_FEATURE_REDACTED_DATASETS)); + err = SET_ERROR(EIO); + goto early_unlock; + } + + SET_BOOKMARK(&zb, dmu_objset_id(db->db_objset), + db->db.db_object, db->db_level, db->db_blkid); + + /* + * All bps of an encrypted os should have the encryption bit set. + * If this is not true it indicates tampering and we report an error. + */ + if (db->db_objset->os_encrypted && !BP_USES_CRYPT(db->db_blkptr)) { + spa_log_error(db->db_objset->os_spa, &zb); + zfs_panic_recover("unencrypted block in encrypted " + "object set %llu", dmu_objset_id(db->db_objset)); + err = SET_ERROR(EIO); + goto early_unlock; + } + + err = dbuf_read_verify_dnode_crypt(db, flags); + if (err != 0) + goto early_unlock; + + DB_DNODE_EXIT(db); + + db->db_state = DB_READ; + DTRACE_SET_STATE(db, "read issued"); + mutex_exit(&db->db_mtx); + + if (DBUF_IS_L2CACHEABLE(db)) + aflags |= ARC_FLAG_L2CACHE; + + dbuf_add_ref(db, NULL); + + zio_flags = (flags & DB_RF_CANFAIL) ? + ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED; + + if ((flags & DB_RF_NO_DECRYPT) && BP_IS_PROTECTED(db->db_blkptr)) + zio_flags |= ZIO_FLAG_RAW; + /* + * The zio layer will copy the provided blkptr later, but we need to + * do this now so that we can release the parent's rwlock. We have to + * do that now so that if dbuf_read_done is called synchronously (on + * an l1 cache hit) we don't acquire the db_mtx while holding the + * parent's rwlock, which would be a lock ordering violation. + */ + blkptr_t bp = *db->db_blkptr; + dmu_buf_unlock_parent(db, dblt, tag); + (void) arc_read(zio, db->db_objset->os_spa, &bp, + dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ, zio_flags, + &aflags, &zb); + return (err); +early_unlock: + DB_DNODE_EXIT(db); + mutex_exit(&db->db_mtx); + dmu_buf_unlock_parent(db, dblt, tag); + return (err); +} + +/* + * This is our just-in-time copy function. It makes a copy of buffers that + * have been modified in a previous transaction group before we access them in + * the current active group. + * + * This function is used in three places: when we are dirtying a buffer for the + * first time in a txg, when we are freeing a range in a dnode that includes + * this buffer, and when we are accessing a buffer which was received compressed + * and later referenced in a WRITE_BYREF record. + * + * Note that when we are called from dbuf_free_range() we do not put a hold on + * the buffer, we just traverse the active dbuf list for the dnode. + */ +static void +dbuf_fix_old_data(dmu_buf_impl_t *db, uint64_t txg) +{ + dbuf_dirty_record_t *dr = list_head(&db->db_dirty_records); + + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(db->db.db_data != NULL); + ASSERT(db->db_level == 0); + ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT); + + if (dr == NULL || + (dr->dt.dl.dr_data != + ((db->db_blkid == DMU_BONUS_BLKID) ? db->db.db_data : db->db_buf))) + return; + + /* + * If the last dirty record for this dbuf has not yet synced + * and its referencing the dbuf data, either: + * reset the reference to point to a new copy, + * or (if there a no active holders) + * just null out the current db_data pointer. + */ + ASSERT3U(dr->dr_txg, >=, txg - 2); + if (db->db_blkid == DMU_BONUS_BLKID) { + dnode_t *dn = DB_DNODE(db); + int bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); + dr->dt.dl.dr_data = kmem_alloc(bonuslen, KM_SLEEP); + arc_space_consume(bonuslen, ARC_SPACE_BONUS); + bcopy(db->db.db_data, dr->dt.dl.dr_data, bonuslen); + } else if (zfs_refcount_count(&db->db_holds) > db->db_dirtycnt) { + arc_buf_t *buf = dbuf_alloc_arcbuf_from_arcbuf(db, db->db_buf); + dr->dt.dl.dr_data = buf; + bcopy(db->db.db_data, buf->b_data, arc_buf_size(buf)); + } else { + db->db_buf = NULL; + dbuf_clear_data(db); + } +} + +int +dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags) +{ + int err = 0; + boolean_t prefetch; + dnode_t *dn; + + /* + * We don't have to hold the mutex to check db_state because it + * can't be freed while we have a hold on the buffer. + */ + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + + if (db->db_state == DB_NOFILL) + return (SET_ERROR(EIO)); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + + prefetch = db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && + (flags & DB_RF_NOPREFETCH) == 0 && dn != NULL && + DBUF_IS_CACHEABLE(db); + + mutex_enter(&db->db_mtx); + if (db->db_state == DB_CACHED) { + spa_t *spa = dn->dn_objset->os_spa; + + /* + * Ensure that this block's dnode has been decrypted if + * the caller has requested decrypted data. + */ + err = dbuf_read_verify_dnode_crypt(db, flags); + + /* + * If the arc buf is compressed or encrypted and the caller + * requested uncompressed data, we need to untransform it + * before returning. We also call arc_untransform() on any + * unauthenticated blocks, which will verify their MAC if + * the key is now available. + */ + if (err == 0 && db->db_buf != NULL && + (flags & DB_RF_NO_DECRYPT) == 0 && + (arc_is_encrypted(db->db_buf) || + arc_is_unauthenticated(db->db_buf) || + arc_get_compression(db->db_buf) != ZIO_COMPRESS_OFF)) { + zbookmark_phys_t zb; + + SET_BOOKMARK(&zb, dmu_objset_id(db->db_objset), + db->db.db_object, db->db_level, db->db_blkid); + dbuf_fix_old_data(db, spa_syncing_txg(spa)); + err = arc_untransform(db->db_buf, spa, &zb, B_FALSE); + dbuf_set_data(db, db->db_buf); + } + mutex_exit(&db->db_mtx); + if (err == 0 && prefetch) { + dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1, B_TRUE, + flags & DB_RF_HAVESTRUCT); + } + DB_DNODE_EXIT(db); + DBUF_STAT_BUMP(hash_hits); + } else if (db->db_state == DB_UNCACHED) { + spa_t *spa = dn->dn_objset->os_spa; + boolean_t need_wait = B_FALSE; + + db_lock_type_t dblt = dmu_buf_lock_parent(db, RW_READER, FTAG); + + if (zio == NULL && + db->db_blkptr != NULL && !BP_IS_HOLE(db->db_blkptr)) { + zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL); + need_wait = B_TRUE; + } + err = dbuf_read_impl(db, zio, flags, dblt, FTAG); + /* + * dbuf_read_impl has dropped db_mtx and our parent's rwlock + * for us + */ + if (!err && prefetch) { + dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1, B_TRUE, + flags & DB_RF_HAVESTRUCT); + } + + DB_DNODE_EXIT(db); + DBUF_STAT_BUMP(hash_misses); + + /* + * If we created a zio_root we must execute it to avoid + * leaking it, even if it isn't attached to any work due + * to an error in dbuf_read_impl(). + */ + if (need_wait) { + if (err == 0) + err = zio_wait(zio); + else + VERIFY0(zio_wait(zio)); + } + } else { + /* + * Another reader came in while the dbuf was in flight + * between UNCACHED and CACHED. Either a writer will finish + * writing the buffer (sending the dbuf to CACHED) or the + * first reader's request will reach the read_done callback + * and send the dbuf to CACHED. Otherwise, a failure + * occurred and the dbuf went to UNCACHED. + */ + mutex_exit(&db->db_mtx); + if (prefetch) { + dmu_zfetch(&dn->dn_zfetch, db->db_blkid, 1, B_TRUE, + flags & DB_RF_HAVESTRUCT); + } + DB_DNODE_EXIT(db); + DBUF_STAT_BUMP(hash_misses); + + /* Skip the wait per the caller's request. */ + if ((flags & DB_RF_NEVERWAIT) == 0) { + mutex_enter(&db->db_mtx); + while (db->db_state == DB_READ || + db->db_state == DB_FILL) { + ASSERT(db->db_state == DB_READ || + (flags & DB_RF_HAVESTRUCT) == 0); + DTRACE_PROBE2(blocked__read, dmu_buf_impl_t *, + db, zio_t *, zio); + cv_wait(&db->db_changed, &db->db_mtx); + } + if (db->db_state == DB_UNCACHED) + err = SET_ERROR(EIO); + mutex_exit(&db->db_mtx); + } + } + + return (err); +} + +static void +dbuf_noread(dmu_buf_impl_t *db) +{ + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + mutex_enter(&db->db_mtx); + while (db->db_state == DB_READ || db->db_state == DB_FILL) + cv_wait(&db->db_changed, &db->db_mtx); + if (db->db_state == DB_UNCACHED) { + ASSERT(db->db_buf == NULL); + ASSERT(db->db.db_data == NULL); + dbuf_set_data(db, dbuf_alloc_arcbuf(db)); + db->db_state = DB_FILL; + DTRACE_SET_STATE(db, "assigning filled buffer"); + } else if (db->db_state == DB_NOFILL) { + dbuf_clear_data(db); + } else { + ASSERT3U(db->db_state, ==, DB_CACHED); + } + mutex_exit(&db->db_mtx); +} + +void +dbuf_unoverride(dbuf_dirty_record_t *dr) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + blkptr_t *bp = &dr->dt.dl.dr_overridden_by; + uint64_t txg = dr->dr_txg; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + /* + * This assert is valid because dmu_sync() expects to be called by + * a zilog's get_data while holding a range lock. This call only + * comes from dbuf_dirty() callers who must also hold a range lock. + */ + ASSERT(dr->dt.dl.dr_override_state != DR_IN_DMU_SYNC); + ASSERT(db->db_level == 0); + + if (db->db_blkid == DMU_BONUS_BLKID || + dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN) + return; + + ASSERT(db->db_data_pending != dr); + + /* free this block */ + if (!BP_IS_HOLE(bp) && !dr->dt.dl.dr_nopwrite) + zio_free(db->db_objset->os_spa, txg, bp); + + dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; + dr->dt.dl.dr_nopwrite = B_FALSE; + dr->dt.dl.dr_has_raw_params = B_FALSE; + + /* + * Release the already-written buffer, so we leave it in + * a consistent dirty state. Note that all callers are + * modifying the buffer, so they will immediately do + * another (redundant) arc_release(). Therefore, leave + * the buf thawed to save the effort of freezing & + * immediately re-thawing it. + */ + arc_release(dr->dt.dl.dr_data, db); +} + +/* + * Evict (if its unreferenced) or clear (if its referenced) any level-0 + * data blocks in the free range, so that any future readers will find + * empty blocks. + */ +void +dbuf_free_range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, + dmu_tx_t *tx) +{ + dmu_buf_impl_t *db_search; + dmu_buf_impl_t *db, *db_next; + uint64_t txg = tx->tx_txg; + avl_index_t where; + dbuf_dirty_record_t *dr; + + if (end_blkid > dn->dn_maxblkid && + !(start_blkid == DMU_SPILL_BLKID || end_blkid == DMU_SPILL_BLKID)) + end_blkid = dn->dn_maxblkid; + dprintf_dnode(dn, "start=%llu end=%llu\n", start_blkid, end_blkid); + + db_search = kmem_alloc(sizeof (dmu_buf_impl_t), KM_SLEEP); + db_search->db_level = 0; + db_search->db_blkid = start_blkid; + db_search->db_state = DB_SEARCH; + + mutex_enter(&dn->dn_dbufs_mtx); + db = avl_find(&dn->dn_dbufs, db_search, &where); + ASSERT3P(db, ==, NULL); + + db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); + + for (; db != NULL; db = db_next) { + db_next = AVL_NEXT(&dn->dn_dbufs, db); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + + if (db->db_level != 0 || db->db_blkid > end_blkid) { + break; + } + ASSERT3U(db->db_blkid, >=, start_blkid); + + /* found a level 0 buffer in the range */ + mutex_enter(&db->db_mtx); + if (dbuf_undirty(db, tx)) { + /* mutex has been dropped and dbuf destroyed */ + continue; + } + + if (db->db_state == DB_UNCACHED || + db->db_state == DB_NOFILL || + db->db_state == DB_EVICTING) { + ASSERT(db->db.db_data == NULL); + mutex_exit(&db->db_mtx); + continue; + } + if (db->db_state == DB_READ || db->db_state == DB_FILL) { + /* will be handled in dbuf_read_done or dbuf_rele */ + db->db_freed_in_flight = TRUE; + mutex_exit(&db->db_mtx); + continue; + } + if (zfs_refcount_count(&db->db_holds) == 0) { + ASSERT(db->db_buf); + dbuf_destroy(db); + continue; + } + /* The dbuf is referenced */ + + dr = list_head(&db->db_dirty_records); + if (dr != NULL) { + if (dr->dr_txg == txg) { + /* + * This buffer is "in-use", re-adjust the file + * size to reflect that this buffer may + * contain new data when we sync. + */ + if (db->db_blkid != DMU_SPILL_BLKID && + db->db_blkid > dn->dn_maxblkid) + dn->dn_maxblkid = db->db_blkid; + dbuf_unoverride(dr); + } else { + /* + * This dbuf is not dirty in the open context. + * Either uncache it (if its not referenced in + * the open context) or reset its contents to + * empty. + */ + dbuf_fix_old_data(db, txg); + } + } + /* clear the contents if its cached */ + if (db->db_state == DB_CACHED) { + ASSERT(db->db.db_data != NULL); + arc_release(db->db_buf, db); + rw_enter(&db->db_rwlock, RW_WRITER); + bzero(db->db.db_data, db->db.db_size); + rw_exit(&db->db_rwlock); + arc_buf_freeze(db->db_buf); + } + + mutex_exit(&db->db_mtx); + } + + kmem_free(db_search, sizeof (dmu_buf_impl_t)); + mutex_exit(&dn->dn_dbufs_mtx); +} + +void +dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx) +{ + arc_buf_t *buf, *old_buf; + dbuf_dirty_record_t *dr; + int osize = db->db.db_size; + arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db); + dnode_t *dn; + + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + + /* + * XXX we should be doing a dbuf_read, checking the return + * value and returning that up to our callers + */ + dmu_buf_will_dirty(&db->db, tx); + + /* create the data buffer for the new block */ + buf = arc_alloc_buf(dn->dn_objset->os_spa, db, type, size); + + /* copy old block data to the new block */ + old_buf = db->db_buf; + bcopy(old_buf->b_data, buf->b_data, MIN(osize, size)); + /* zero the remainder */ + if (size > osize) + bzero((uint8_t *)buf->b_data + osize, size - osize); + + mutex_enter(&db->db_mtx); + dbuf_set_data(db, buf); + arc_buf_destroy(old_buf, db); + db->db.db_size = size; + + dr = list_head(&db->db_dirty_records); + /* dirty record added by dmu_buf_will_dirty() */ + VERIFY(dr != NULL); + if (db->db_level == 0) + dr->dt.dl.dr_data = buf; + ASSERT3U(dr->dr_txg, ==, tx->tx_txg); + ASSERT3U(dr->dr_accounted, ==, osize); + dr->dr_accounted = size; + mutex_exit(&db->db_mtx); + + dmu_objset_willuse_space(dn->dn_objset, size - osize, tx); + DB_DNODE_EXIT(db); +} + +void +dbuf_release_bp(dmu_buf_impl_t *db) +{ + objset_t *os __maybe_unused = db->db_objset; + + ASSERT(dsl_pool_sync_context(dmu_objset_pool(os))); + ASSERT(arc_released(os->os_phys_buf) || + list_link_active(&os->os_dsl_dataset->ds_synced_link)); + ASSERT(db->db_parent == NULL || arc_released(db->db_parent->db_buf)); + + (void) arc_release(db->db_buf, db); +} + +/* + * We already have a dirty record for this TXG, and we are being + * dirtied again. + */ +static void +dbuf_redirty(dbuf_dirty_record_t *dr) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + + if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) { + /* + * If this buffer has already been written out, + * we now need to reset its state. + */ + dbuf_unoverride(dr); + if (db->db.db_object != DMU_META_DNODE_OBJECT && + db->db_state != DB_NOFILL) { + /* Already released on initial dirty, so just thaw. */ + ASSERT(arc_released(db->db_buf)); + arc_buf_thaw(db->db_buf); + } + } +} + +dbuf_dirty_record_t * +dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx) +{ + dnode_t *dn; + objset_t *os; + dbuf_dirty_record_t *dr, *dr_next, *dr_head; + int txgoff = tx->tx_txg & TXG_MASK; + boolean_t drop_struct_rwlock = B_FALSE; + + ASSERT(tx->tx_txg != 0); + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + DMU_TX_DIRTY_BUF(tx, db); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + /* + * Shouldn't dirty a regular buffer in syncing context. Private + * objects may be dirtied in syncing context, but only if they + * were already pre-dirtied in open context. + */ +#ifdef ZFS_DEBUG + if (dn->dn_objset->os_dsl_dataset != NULL) { + rrw_enter(&dn->dn_objset->os_dsl_dataset->ds_bp_rwlock, + RW_READER, FTAG); + } + ASSERT(!dmu_tx_is_syncing(tx) || + BP_IS_HOLE(dn->dn_objset->os_rootbp) || + DMU_OBJECT_IS_SPECIAL(dn->dn_object) || + dn->dn_objset->os_dsl_dataset == NULL); + if (dn->dn_objset->os_dsl_dataset != NULL) + rrw_exit(&dn->dn_objset->os_dsl_dataset->ds_bp_rwlock, FTAG); +#endif + /* + * We make this assert for private objects as well, but after we + * check if we're already dirty. They are allowed to re-dirty + * in syncing context. + */ + ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || + dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == + (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); + + mutex_enter(&db->db_mtx); + /* + * XXX make this true for indirects too? The problem is that + * transactions created with dmu_tx_create_assigned() from + * syncing context don't bother holding ahead. + */ + ASSERT(db->db_level != 0 || + db->db_state == DB_CACHED || db->db_state == DB_FILL || + db->db_state == DB_NOFILL); + + mutex_enter(&dn->dn_mtx); + dnode_set_dirtyctx(dn, tx, db); + if (tx->tx_txg > dn->dn_dirty_txg) + dn->dn_dirty_txg = tx->tx_txg; + mutex_exit(&dn->dn_mtx); + + if (db->db_blkid == DMU_SPILL_BLKID) + dn->dn_have_spill = B_TRUE; + + /* + * If this buffer is already dirty, we're done. + */ + dr_head = list_head(&db->db_dirty_records); + ASSERT(dr_head == NULL || dr_head->dr_txg <= tx->tx_txg || + db->db.db_object == DMU_META_DNODE_OBJECT); + dr_next = dbuf_find_dirty_lte(db, tx->tx_txg); + if (dr_next && dr_next->dr_txg == tx->tx_txg) { + DB_DNODE_EXIT(db); + + dbuf_redirty(dr_next); + mutex_exit(&db->db_mtx); + return (dr_next); + } + + /* + * Only valid if not already dirty. + */ + ASSERT(dn->dn_object == 0 || + dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx == + (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN)); + + ASSERT3U(dn->dn_nlevels, >, db->db_level); + + /* + * We should only be dirtying in syncing context if it's the + * mos or we're initializing the os or it's a special object. + * However, we are allowed to dirty in syncing context provided + * we already dirtied it in open context. Hence we must make + * this assertion only if we're not already dirty. + */ + os = dn->dn_objset; + VERIFY3U(tx->tx_txg, <=, spa_final_dirty_txg(os->os_spa)); +#ifdef ZFS_DEBUG + if (dn->dn_objset->os_dsl_dataset != NULL) + rrw_enter(&os->os_dsl_dataset->ds_bp_rwlock, RW_READER, FTAG); + ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) || + os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp)); + if (dn->dn_objset->os_dsl_dataset != NULL) + rrw_exit(&os->os_dsl_dataset->ds_bp_rwlock, FTAG); +#endif + ASSERT(db->db.db_size != 0); + + dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); + + if (db->db_blkid != DMU_BONUS_BLKID) { + dmu_objset_willuse_space(os, db->db.db_size, tx); + } + + /* + * If this buffer is dirty in an old transaction group we need + * to make a copy of it so that the changes we make in this + * transaction group won't leak out when we sync the older txg. + */ + dr = kmem_zalloc(sizeof (dbuf_dirty_record_t), KM_SLEEP); + list_link_init(&dr->dr_dirty_node); + list_link_init(&dr->dr_dbuf_node); + if (db->db_level == 0) { + void *data_old = db->db_buf; + + if (db->db_state != DB_NOFILL) { + if (db->db_blkid == DMU_BONUS_BLKID) { + dbuf_fix_old_data(db, tx->tx_txg); + data_old = db->db.db_data; + } else if (db->db.db_object != DMU_META_DNODE_OBJECT) { + /* + * Release the data buffer from the cache so + * that we can modify it without impacting + * possible other users of this cached data + * block. Note that indirect blocks and + * private objects are not released until the + * syncing state (since they are only modified + * then). + */ + arc_release(db->db_buf, db); + dbuf_fix_old_data(db, tx->tx_txg); + data_old = db->db_buf; + } + ASSERT(data_old != NULL); + } + dr->dt.dl.dr_data = data_old; + } else { + mutex_init(&dr->dt.di.dr_mtx, NULL, MUTEX_NOLOCKDEP, NULL); + list_create(&dr->dt.di.dr_children, + sizeof (dbuf_dirty_record_t), + offsetof(dbuf_dirty_record_t, dr_dirty_node)); + } + if (db->db_blkid != DMU_BONUS_BLKID) + dr->dr_accounted = db->db.db_size; + dr->dr_dbuf = db; + dr->dr_txg = tx->tx_txg; + list_insert_before(&db->db_dirty_records, dr_next, dr); + + /* + * We could have been freed_in_flight between the dbuf_noread + * and dbuf_dirty. We win, as though the dbuf_noread() had + * happened after the free. + */ + if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && + db->db_blkid != DMU_SPILL_BLKID) { + mutex_enter(&dn->dn_mtx); + if (dn->dn_free_ranges[txgoff] != NULL) { + range_tree_clear(dn->dn_free_ranges[txgoff], + db->db_blkid, 1); + } + mutex_exit(&dn->dn_mtx); + db->db_freed_in_flight = FALSE; + } + + /* + * This buffer is now part of this txg + */ + dbuf_add_ref(db, (void *)(uintptr_t)tx->tx_txg); + db->db_dirtycnt += 1; + ASSERT3U(db->db_dirtycnt, <=, 3); + + mutex_exit(&db->db_mtx); + + if (db->db_blkid == DMU_BONUS_BLKID || + db->db_blkid == DMU_SPILL_BLKID) { + mutex_enter(&dn->dn_mtx); + ASSERT(!list_link_active(&dr->dr_dirty_node)); + list_insert_tail(&dn->dn_dirty_records[txgoff], dr); + mutex_exit(&dn->dn_mtx); + dnode_setdirty(dn, tx); + DB_DNODE_EXIT(db); + return (dr); + } + + if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { + rw_enter(&dn->dn_struct_rwlock, RW_READER); + drop_struct_rwlock = B_TRUE; + } + + /* + * If we are overwriting a dedup BP, then unless it is snapshotted, + * when we get to syncing context we will need to decrement its + * refcount in the DDT. Prefetch the relevant DDT block so that + * syncing context won't have to wait for the i/o. + */ + if (db->db_blkptr != NULL) { + db_lock_type_t dblt = dmu_buf_lock_parent(db, RW_READER, FTAG); + ddt_prefetch(os->os_spa, db->db_blkptr); + dmu_buf_unlock_parent(db, dblt, FTAG); + } + + /* + * We need to hold the dn_struct_rwlock to make this assertion, + * because it protects dn_phys / dn_next_nlevels from changing. + */ + ASSERT((dn->dn_phys->dn_nlevels == 0 && db->db_level == 0) || + dn->dn_phys->dn_nlevels > db->db_level || + dn->dn_next_nlevels[txgoff] > db->db_level || + dn->dn_next_nlevels[(tx->tx_txg-1) & TXG_MASK] > db->db_level || + dn->dn_next_nlevels[(tx->tx_txg-2) & TXG_MASK] > db->db_level); + + + if (db->db_level == 0) { + ASSERT(!db->db_objset->os_raw_receive || + dn->dn_maxblkid >= db->db_blkid); + dnode_new_blkid(dn, db->db_blkid, tx, + drop_struct_rwlock, B_FALSE); + ASSERT(dn->dn_maxblkid >= db->db_blkid); + } + + if (db->db_level+1 < dn->dn_nlevels) { + dmu_buf_impl_t *parent = db->db_parent; + dbuf_dirty_record_t *di; + int parent_held = FALSE; + + if (db->db_parent == NULL || db->db_parent == dn->dn_dbuf) { + int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + parent = dbuf_hold_level(dn, db->db_level + 1, + db->db_blkid >> epbs, FTAG); + ASSERT(parent != NULL); + parent_held = TRUE; + } + if (drop_struct_rwlock) + rw_exit(&dn->dn_struct_rwlock); + ASSERT3U(db->db_level + 1, ==, parent->db_level); + di = dbuf_dirty(parent, tx); + if (parent_held) + dbuf_rele(parent, FTAG); + + mutex_enter(&db->db_mtx); + /* + * Since we've dropped the mutex, it's possible that + * dbuf_undirty() might have changed this out from under us. + */ + if (list_head(&db->db_dirty_records) == dr || + dn->dn_object == DMU_META_DNODE_OBJECT) { + mutex_enter(&di->dt.di.dr_mtx); + ASSERT3U(di->dr_txg, ==, tx->tx_txg); + ASSERT(!list_link_active(&dr->dr_dirty_node)); + list_insert_tail(&di->dt.di.dr_children, dr); + mutex_exit(&di->dt.di.dr_mtx); + dr->dr_parent = di; + } + mutex_exit(&db->db_mtx); + } else { + ASSERT(db->db_level + 1 == dn->dn_nlevels); + ASSERT(db->db_blkid < dn->dn_nblkptr); + ASSERT(db->db_parent == NULL || db->db_parent == dn->dn_dbuf); + mutex_enter(&dn->dn_mtx); + ASSERT(!list_link_active(&dr->dr_dirty_node)); + list_insert_tail(&dn->dn_dirty_records[txgoff], dr); + mutex_exit(&dn->dn_mtx); + if (drop_struct_rwlock) + rw_exit(&dn->dn_struct_rwlock); + } + + dnode_setdirty(dn, tx); + DB_DNODE_EXIT(db); + return (dr); +} + +static void +dbuf_undirty_bonus(dbuf_dirty_record_t *dr) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + + if (dr->dt.dl.dr_data != db->db.db_data) { + struct dnode *dn = DB_DNODE(db); + int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); + + kmem_free(dr->dt.dl.dr_data, max_bonuslen); + arc_space_return(max_bonuslen, ARC_SPACE_BONUS); + } + db->db_data_pending = NULL; + ASSERT(list_next(&db->db_dirty_records, dr) == NULL); + list_remove(&db->db_dirty_records, dr); + if (dr->dr_dbuf->db_level != 0) { + mutex_destroy(&dr->dt.di.dr_mtx); + list_destroy(&dr->dt.di.dr_children); + } + kmem_free(dr, sizeof (dbuf_dirty_record_t)); + ASSERT3U(db->db_dirtycnt, >, 0); + db->db_dirtycnt -= 1; +} + +/* + * Undirty a buffer in the transaction group referenced by the given + * transaction. Return whether this evicted the dbuf. + */ +static boolean_t +dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx) +{ + dnode_t *dn; + uint64_t txg = tx->tx_txg; + dbuf_dirty_record_t *dr; + + ASSERT(txg != 0); + + /* + * Due to our use of dn_nlevels below, this can only be called + * in open context, unless we are operating on the MOS. + * From syncing context, dn_nlevels may be different from the + * dn_nlevels used when dbuf was dirtied. + */ + ASSERT(db->db_objset == + dmu_objset_pool(db->db_objset)->dp_meta_objset || + txg != spa_syncing_txg(dmu_objset_spa(db->db_objset))); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT0(db->db_level); + ASSERT(MUTEX_HELD(&db->db_mtx)); + + /* + * If this buffer is not dirty, we're done. + */ + dr = dbuf_find_dirty_eq(db, txg); + if (dr == NULL) + return (B_FALSE); + ASSERT(dr->dr_dbuf == db); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + + dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size); + + ASSERT(db->db.db_size != 0); + + dsl_pool_undirty_space(dmu_objset_pool(dn->dn_objset), + dr->dr_accounted, txg); + + list_remove(&db->db_dirty_records, dr); + + /* + * Note that there are three places in dbuf_dirty() + * where this dirty record may be put on a list. + * Make sure to do a list_remove corresponding to + * every one of those list_insert calls. + */ + if (dr->dr_parent) { + mutex_enter(&dr->dr_parent->dt.di.dr_mtx); + list_remove(&dr->dr_parent->dt.di.dr_children, dr); + mutex_exit(&dr->dr_parent->dt.di.dr_mtx); + } else if (db->db_blkid == DMU_SPILL_BLKID || + db->db_level + 1 == dn->dn_nlevels) { + ASSERT(db->db_blkptr == NULL || db->db_parent == dn->dn_dbuf); + mutex_enter(&dn->dn_mtx); + list_remove(&dn->dn_dirty_records[txg & TXG_MASK], dr); + mutex_exit(&dn->dn_mtx); + } + DB_DNODE_EXIT(db); + + if (db->db_state != DB_NOFILL) { + dbuf_unoverride(dr); + + ASSERT(db->db_buf != NULL); + ASSERT(dr->dt.dl.dr_data != NULL); + if (dr->dt.dl.dr_data != db->db_buf) + arc_buf_destroy(dr->dt.dl.dr_data, db); + } + + kmem_free(dr, sizeof (dbuf_dirty_record_t)); + + ASSERT(db->db_dirtycnt > 0); + db->db_dirtycnt -= 1; + + if (zfs_refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) { + ASSERT(db->db_state == DB_NOFILL || arc_released(db->db_buf)); + dbuf_destroy(db); + return (B_TRUE); + } + + return (B_FALSE); +} + +static void +dmu_buf_will_dirty_impl(dmu_buf_t *db_fake, int flags, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + ASSERT(tx->tx_txg != 0); + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + + /* + * Quick check for dirtiness. For already dirty blocks, this + * reduces runtime of this function by >90%, and overall performance + * by 50% for some workloads (e.g. file deletion with indirect blocks + * cached). + */ + mutex_enter(&db->db_mtx); + + if (db->db_state == DB_CACHED) { + dbuf_dirty_record_t *dr = dbuf_find_dirty_eq(db, tx->tx_txg); + /* + * It's possible that it is already dirty but not cached, + * because there are some calls to dbuf_dirty() that don't + * go through dmu_buf_will_dirty(). + */ + if (dr != NULL) { + /* This dbuf is already dirty and cached. */ + dbuf_redirty(dr); + mutex_exit(&db->db_mtx); + return; + } + } + mutex_exit(&db->db_mtx); + + DB_DNODE_ENTER(db); + if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock)) + flags |= DB_RF_HAVESTRUCT; + DB_DNODE_EXIT(db); + (void) dbuf_read(db, NULL, flags); + (void) dbuf_dirty(db, tx); +} + +void +dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) +{ + dmu_buf_will_dirty_impl(db_fake, + DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH, tx); +} + +boolean_t +dmu_buf_is_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + dbuf_dirty_record_t *dr; + + mutex_enter(&db->db_mtx); + dr = dbuf_find_dirty_eq(db, tx->tx_txg); + mutex_exit(&db->db_mtx); + return (dr != NULL); +} + +void +dmu_buf_will_not_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + db->db_state = DB_NOFILL; + DTRACE_SET_STATE(db, "allocating NOFILL buffer"); + dmu_buf_will_fill(db_fake, tx); +} + +void +dmu_buf_will_fill(dmu_buf_t *db_fake, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT(tx->tx_txg != 0); + ASSERT(db->db_level == 0); + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + + ASSERT(db->db.db_object != DMU_META_DNODE_OBJECT || + dmu_tx_private_ok(tx)); + + dbuf_noread(db); + (void) dbuf_dirty(db, tx); +} + +/* + * This function is effectively the same as dmu_buf_will_dirty(), but + * indicates the caller expects raw encrypted data in the db, and provides + * the crypt params (byteorder, salt, iv, mac) which should be stored in the + * blkptr_t when this dbuf is written. This is only used for blocks of + * dnodes, during raw receive. + */ +void +dmu_buf_set_crypt_params(dmu_buf_t *db_fake, boolean_t byteorder, + const uint8_t *salt, const uint8_t *iv, const uint8_t *mac, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + dbuf_dirty_record_t *dr; + + /* + * dr_has_raw_params is only processed for blocks of dnodes + * (see dbuf_sync_dnode_leaf_crypt()). + */ + ASSERT3U(db->db.db_object, ==, DMU_META_DNODE_OBJECT); + ASSERT3U(db->db_level, ==, 0); + ASSERT(db->db_objset->os_raw_receive); + + dmu_buf_will_dirty_impl(db_fake, + DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH | DB_RF_NO_DECRYPT, tx); + + dr = dbuf_find_dirty_eq(db, tx->tx_txg); + + ASSERT3P(dr, !=, NULL); + + dr->dt.dl.dr_has_raw_params = B_TRUE; + dr->dt.dl.dr_byteorder = byteorder; + bcopy(salt, dr->dt.dl.dr_salt, ZIO_DATA_SALT_LEN); + bcopy(iv, dr->dt.dl.dr_iv, ZIO_DATA_IV_LEN); + bcopy(mac, dr->dt.dl.dr_mac, ZIO_DATA_MAC_LEN); +} + +static void +dbuf_override_impl(dmu_buf_impl_t *db, const blkptr_t *bp, dmu_tx_t *tx) +{ + struct dirty_leaf *dl; + dbuf_dirty_record_t *dr; + + dr = list_head(&db->db_dirty_records); + ASSERT3U(dr->dr_txg, ==, tx->tx_txg); + dl = &dr->dt.dl; + dl->dr_overridden_by = *bp; + dl->dr_override_state = DR_OVERRIDDEN; + dl->dr_overridden_by.blk_birth = dr->dr_txg; +} + +/* ARGSUSED */ +void +dmu_buf_fill_done(dmu_buf_t *dbuf, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; + dbuf_states_t old_state; + mutex_enter(&db->db_mtx); + DBUF_VERIFY(db); + + old_state = db->db_state; + db->db_state = DB_CACHED; + if (old_state == DB_FILL) { + if (db->db_level == 0 && db->db_freed_in_flight) { + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + /* we were freed while filling */ + /* XXX dbuf_undirty? */ + bzero(db->db.db_data, db->db.db_size); + db->db_freed_in_flight = FALSE; + DTRACE_SET_STATE(db, + "fill done handling freed in flight"); + } else { + DTRACE_SET_STATE(db, "fill done"); + } + cv_broadcast(&db->db_changed); + } + mutex_exit(&db->db_mtx); +} + +void +dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, + bp_embedded_type_t etype, enum zio_compress comp, + int uncompressed_size, int compressed_size, int byteorder, + dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; + struct dirty_leaf *dl; + dmu_object_type_t type; + dbuf_dirty_record_t *dr; + + if (etype == BP_EMBEDDED_TYPE_DATA) { + ASSERT(spa_feature_is_active(dmu_objset_spa(db->db_objset), + SPA_FEATURE_EMBEDDED_DATA)); + } + + DB_DNODE_ENTER(db); + type = DB_DNODE(db)->dn_type; + DB_DNODE_EXIT(db); + + ASSERT0(db->db_level); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + + dmu_buf_will_not_fill(dbuf, tx); + + dr = list_head(&db->db_dirty_records); + ASSERT3U(dr->dr_txg, ==, tx->tx_txg); + dl = &dr->dt.dl; + encode_embedded_bp_compressed(&dl->dr_overridden_by, + data, comp, uncompressed_size, compressed_size); + BPE_SET_ETYPE(&dl->dr_overridden_by, etype); + BP_SET_TYPE(&dl->dr_overridden_by, type); + BP_SET_LEVEL(&dl->dr_overridden_by, 0); + BP_SET_BYTEORDER(&dl->dr_overridden_by, byteorder); + + dl->dr_override_state = DR_OVERRIDDEN; + dl->dr_overridden_by.blk_birth = dr->dr_txg; +} + +void +dmu_buf_redact(dmu_buf_t *dbuf, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf; + dmu_object_type_t type; + ASSERT(dsl_dataset_feature_is_active(db->db_objset->os_dsl_dataset, + SPA_FEATURE_REDACTED_DATASETS)); + + DB_DNODE_ENTER(db); + type = DB_DNODE(db)->dn_type; + DB_DNODE_EXIT(db); + + ASSERT0(db->db_level); + dmu_buf_will_not_fill(dbuf, tx); + + blkptr_t bp = { { { {0} } } }; + BP_SET_TYPE(&bp, type); + BP_SET_LEVEL(&bp, 0); + BP_SET_BIRTH(&bp, tx->tx_txg, 0); + BP_SET_REDACTED(&bp); + BPE_SET_LSIZE(&bp, dbuf->db_size); + + dbuf_override_impl(db, &bp, tx); +} + +/* + * Directly assign a provided arc buf to a given dbuf if it's not referenced + * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf. + */ +void +dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx) +{ + ASSERT(!zfs_refcount_is_zero(&db->db_holds)); + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT(db->db_level == 0); + ASSERT3U(dbuf_is_metadata(db), ==, arc_is_metadata(buf)); + ASSERT(buf != NULL); + ASSERT3U(arc_buf_lsize(buf), ==, db->db.db_size); + ASSERT(tx->tx_txg != 0); + + arc_return_buf(buf, db); + ASSERT(arc_released(buf)); + + mutex_enter(&db->db_mtx); + + while (db->db_state == DB_READ || db->db_state == DB_FILL) + cv_wait(&db->db_changed, &db->db_mtx); + + ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED); + + if (db->db_state == DB_CACHED && + zfs_refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) { + /* + * In practice, we will never have a case where we have an + * encrypted arc buffer while additional holds exist on the + * dbuf. We don't handle this here so we simply assert that + * fact instead. + */ + ASSERT(!arc_is_encrypted(buf)); + mutex_exit(&db->db_mtx); + (void) dbuf_dirty(db, tx); + bcopy(buf->b_data, db->db.db_data, db->db.db_size); + arc_buf_destroy(buf, db); + xuio_stat_wbuf_copied(); + return; + } + + xuio_stat_wbuf_nocopy(); + if (db->db_state == DB_CACHED) { + dbuf_dirty_record_t *dr = list_head(&db->db_dirty_records); + + ASSERT(db->db_buf != NULL); + if (dr != NULL && dr->dr_txg == tx->tx_txg) { + ASSERT(dr->dt.dl.dr_data == db->db_buf); + + if (!arc_released(db->db_buf)) { + ASSERT(dr->dt.dl.dr_override_state == + DR_OVERRIDDEN); + arc_release(db->db_buf, db); + } + dr->dt.dl.dr_data = buf; + arc_buf_destroy(db->db_buf, db); + } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) { + arc_release(db->db_buf, db); + arc_buf_destroy(db->db_buf, db); + } + db->db_buf = NULL; + } + ASSERT(db->db_buf == NULL); + dbuf_set_data(db, buf); + db->db_state = DB_FILL; + DTRACE_SET_STATE(db, "filling assigned arcbuf"); + mutex_exit(&db->db_mtx); + (void) dbuf_dirty(db, tx); + dmu_buf_fill_done(&db->db, tx); +} + +void +dbuf_destroy(dmu_buf_impl_t *db) +{ + dnode_t *dn; + dmu_buf_impl_t *parent = db->db_parent; + dmu_buf_impl_t *dndb; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(zfs_refcount_is_zero(&db->db_holds)); + + if (db->db_buf != NULL) { + arc_buf_destroy(db->db_buf, db); + db->db_buf = NULL; + } + + if (db->db_blkid == DMU_BONUS_BLKID) { + int slots = DB_DNODE(db)->dn_num_slots; + int bonuslen = DN_SLOTS_TO_BONUSLEN(slots); + if (db->db.db_data != NULL) { + kmem_free(db->db.db_data, bonuslen); + arc_space_return(bonuslen, ARC_SPACE_BONUS); + db->db_state = DB_UNCACHED; + DTRACE_SET_STATE(db, "buffer cleared"); + } + } + + dbuf_clear_data(db); + + if (multilist_link_active(&db->db_cache_link)) { + ASSERT(db->db_caching_status == DB_DBUF_CACHE || + db->db_caching_status == DB_DBUF_METADATA_CACHE); + + multilist_remove(dbuf_caches[db->db_caching_status].cache, db); + (void) zfs_refcount_remove_many( + &dbuf_caches[db->db_caching_status].size, + db->db.db_size, db); + + if (db->db_caching_status == DB_DBUF_METADATA_CACHE) { + DBUF_STAT_BUMPDOWN(metadata_cache_count); + } else { + DBUF_STAT_BUMPDOWN(cache_levels[db->db_level]); + DBUF_STAT_BUMPDOWN(cache_count); + DBUF_STAT_DECR(cache_levels_bytes[db->db_level], + db->db.db_size); + } + db->db_caching_status = DB_NO_CACHE; + } + + ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL); + ASSERT(db->db_data_pending == NULL); + ASSERT(list_is_empty(&db->db_dirty_records)); + + db->db_state = DB_EVICTING; + DTRACE_SET_STATE(db, "buffer eviction started"); + db->db_blkptr = NULL; + + /* + * Now that db_state is DB_EVICTING, nobody else can find this via + * the hash table. We can now drop db_mtx, which allows us to + * acquire the dn_dbufs_mtx. + */ + mutex_exit(&db->db_mtx); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + dndb = dn->dn_dbuf; + if (db->db_blkid != DMU_BONUS_BLKID) { + boolean_t needlock = !MUTEX_HELD(&dn->dn_dbufs_mtx); + if (needlock) + mutex_enter_nested(&dn->dn_dbufs_mtx, + NESTED_SINGLE); + avl_remove(&dn->dn_dbufs, db); + membar_producer(); + DB_DNODE_EXIT(db); + if (needlock) + mutex_exit(&dn->dn_dbufs_mtx); + /* + * Decrementing the dbuf count means that the hold corresponding + * to the removed dbuf is no longer discounted in dnode_move(), + * so the dnode cannot be moved until after we release the hold. + * The membar_producer() ensures visibility of the decremented + * value in dnode_move(), since DB_DNODE_EXIT doesn't actually + * release any lock. + */ + mutex_enter(&dn->dn_mtx); + dnode_rele_and_unlock(dn, db, B_TRUE); + db->db_dnode_handle = NULL; + + dbuf_hash_remove(db); + } else { + DB_DNODE_EXIT(db); + } + + ASSERT(zfs_refcount_is_zero(&db->db_holds)); + + db->db_parent = NULL; + + ASSERT(db->db_buf == NULL); + ASSERT(db->db.db_data == NULL); + ASSERT(db->db_hash_next == NULL); + ASSERT(db->db_blkptr == NULL); + ASSERT(db->db_data_pending == NULL); + ASSERT3U(db->db_caching_status, ==, DB_NO_CACHE); + ASSERT(!multilist_link_active(&db->db_cache_link)); + + kmem_cache_free(dbuf_kmem_cache, db); + arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_DBUF); + + /* + * If this dbuf is referenced from an indirect dbuf, + * decrement the ref count on the indirect dbuf. + */ + if (parent && parent != dndb) { + mutex_enter(&parent->db_mtx); + dbuf_rele_and_unlock(parent, db, B_TRUE); + } +} + +/* + * Note: While bpp will always be updated if the function returns success, + * parentp will not be updated if the dnode does not have dn_dbuf filled in; + * this happens when the dnode is the meta-dnode, or {user|group|project}used + * object. + */ +__attribute__((always_inline)) +static inline int +dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse, + dmu_buf_impl_t **parentp, blkptr_t **bpp) +{ + *parentp = NULL; + *bpp = NULL; + + ASSERT(blkid != DMU_BONUS_BLKID); + + if (blkid == DMU_SPILL_BLKID) { + mutex_enter(&dn->dn_mtx); + if (dn->dn_have_spill && + (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) + *bpp = DN_SPILL_BLKPTR(dn->dn_phys); + else + *bpp = NULL; + dbuf_add_ref(dn->dn_dbuf, NULL); + *parentp = dn->dn_dbuf; + mutex_exit(&dn->dn_mtx); + return (0); + } + + int nlevels = + (dn->dn_phys->dn_nlevels == 0) ? 1 : dn->dn_phys->dn_nlevels; + int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; + + ASSERT3U(level * epbs, <, 64); + ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); + /* + * This assertion shouldn't trip as long as the max indirect block size + * is less than 1M. The reason for this is that up to that point, + * the number of levels required to address an entire object with blocks + * of size SPA_MINBLOCKSIZE satisfies nlevels * epbs + 1 <= 64. In + * other words, if N * epbs + 1 > 64, then if (N-1) * epbs + 1 > 55 + * (i.e. we can address the entire object), objects will all use at most + * N-1 levels and the assertion won't overflow. However, once epbs is + * 13, 4 * 13 + 1 = 53, but 5 * 13 + 1 = 66. Then, 4 levels will not be + * enough to address an entire object, so objects will have 5 levels, + * but then this assertion will overflow. + * + * All this is to say that if we ever increase DN_MAX_INDBLKSHIFT, we + * need to redo this logic to handle overflows. + */ + ASSERT(level >= nlevels || + ((nlevels - level - 1) * epbs) + + highbit64(dn->dn_phys->dn_nblkptr) <= 64); + if (level >= nlevels || + blkid >= ((uint64_t)dn->dn_phys->dn_nblkptr << + ((nlevels - level - 1) * epbs)) || + (fail_sparse && + blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) { + /* the buffer has no parent yet */ + return (SET_ERROR(ENOENT)); + } else if (level < nlevels-1) { + /* this block is referenced from an indirect block */ + int err; + + err = dbuf_hold_impl(dn, level + 1, + blkid >> epbs, fail_sparse, FALSE, NULL, parentp); + + if (err) + return (err); + err = dbuf_read(*parentp, NULL, + (DB_RF_HAVESTRUCT | DB_RF_NOPREFETCH | DB_RF_CANFAIL)); + if (err) { + dbuf_rele(*parentp, NULL); + *parentp = NULL; + return (err); + } + rw_enter(&(*parentp)->db_rwlock, RW_READER); + *bpp = ((blkptr_t *)(*parentp)->db.db_data) + + (blkid & ((1ULL << epbs) - 1)); + if (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs))) + ASSERT(BP_IS_HOLE(*bpp)); + rw_exit(&(*parentp)->db_rwlock); + return (0); + } else { + /* the block is referenced from the dnode */ + ASSERT3U(level, ==, nlevels-1); + ASSERT(dn->dn_phys->dn_nblkptr == 0 || + blkid < dn->dn_phys->dn_nblkptr); + if (dn->dn_dbuf) { + dbuf_add_ref(dn->dn_dbuf, NULL); + *parentp = dn->dn_dbuf; + } + *bpp = &dn->dn_phys->dn_blkptr[blkid]; + return (0); + } +} + +static dmu_buf_impl_t * +dbuf_create(dnode_t *dn, uint8_t level, uint64_t blkid, + dmu_buf_impl_t *parent, blkptr_t *blkptr) +{ + objset_t *os = dn->dn_objset; + dmu_buf_impl_t *db, *odb; + + ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); + ASSERT(dn->dn_type != DMU_OT_NONE); + + db = kmem_cache_alloc(dbuf_kmem_cache, KM_SLEEP); + + list_create(&db->db_dirty_records, sizeof (dbuf_dirty_record_t), + offsetof(dbuf_dirty_record_t, dr_dbuf_node)); + + db->db_objset = os; + db->db.db_object = dn->dn_object; + db->db_level = level; + db->db_blkid = blkid; + db->db_dirtycnt = 0; + db->db_dnode_handle = dn->dn_handle; + db->db_parent = parent; + db->db_blkptr = blkptr; + + db->db_user = NULL; + db->db_user_immediate_evict = FALSE; + db->db_freed_in_flight = FALSE; + db->db_pending_evict = FALSE; + + if (blkid == DMU_BONUS_BLKID) { + ASSERT3P(parent, ==, dn->dn_dbuf); + db->db.db_size = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - + (dn->dn_nblkptr-1) * sizeof (blkptr_t); + ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen); + db->db.db_offset = DMU_BONUS_BLKID; + db->db_state = DB_UNCACHED; + DTRACE_SET_STATE(db, "bonus buffer created"); + db->db_caching_status = DB_NO_CACHE; + /* the bonus dbuf is not placed in the hash table */ + arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_DBUF); + return (db); + } else if (blkid == DMU_SPILL_BLKID) { + db->db.db_size = (blkptr != NULL) ? + BP_GET_LSIZE(blkptr) : SPA_MINBLOCKSIZE; + db->db.db_offset = 0; + } else { + int blocksize = + db->db_level ? 1 << dn->dn_indblkshift : dn->dn_datablksz; + db->db.db_size = blocksize; + db->db.db_offset = db->db_blkid * blocksize; + } + + /* + * Hold the dn_dbufs_mtx while we get the new dbuf + * in the hash table *and* added to the dbufs list. + * This prevents a possible deadlock with someone + * trying to look up this dbuf before it's added to the + * dn_dbufs list. + */ + mutex_enter(&dn->dn_dbufs_mtx); + db->db_state = DB_EVICTING; /* not worth logging this state change */ + if ((odb = dbuf_hash_insert(db)) != NULL) { + /* someone else inserted it first */ + kmem_cache_free(dbuf_kmem_cache, db); + mutex_exit(&dn->dn_dbufs_mtx); + DBUF_STAT_BUMP(hash_insert_race); + return (odb); + } + avl_add(&dn->dn_dbufs, db); + + db->db_state = DB_UNCACHED; + DTRACE_SET_STATE(db, "regular buffer created"); + db->db_caching_status = DB_NO_CACHE; + mutex_exit(&dn->dn_dbufs_mtx); + arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_DBUF); + + if (parent && parent != dn->dn_dbuf) + dbuf_add_ref(parent, db); + + ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || + zfs_refcount_count(&dn->dn_holds) > 0); + (void) zfs_refcount_add(&dn->dn_holds, db); + + dprintf_dbuf(db, "db=%p\n", db); + + return (db); +} + +/* + * This function returns a block pointer and information about the object, + * given a dnode and a block. This is a publicly accessible version of + * dbuf_findbp that only returns some information, rather than the + * dbuf. Note that the dnode passed in must be held, and the dn_struct_rwlock + * should be locked as (at least) a reader. + */ +int +dbuf_dnode_findbp(dnode_t *dn, uint64_t level, uint64_t blkid, + blkptr_t *bp, uint16_t *datablkszsec, uint8_t *indblkshift) +{ + dmu_buf_impl_t *dbp = NULL; + blkptr_t *bp2; + int err = 0; + ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); + + err = dbuf_findbp(dn, level, blkid, B_FALSE, &dbp, &bp2); + if (err == 0) { + *bp = *bp2; + if (dbp != NULL) + dbuf_rele(dbp, NULL); + if (datablkszsec != NULL) + *datablkszsec = dn->dn_phys->dn_datablkszsec; + if (indblkshift != NULL) + *indblkshift = dn->dn_phys->dn_indblkshift; + } + + return (err); +} + +typedef struct dbuf_prefetch_arg { + spa_t *dpa_spa; /* The spa to issue the prefetch in. */ + zbookmark_phys_t dpa_zb; /* The target block to prefetch. */ + int dpa_epbs; /* Entries (blkptr_t's) Per Block Shift. */ + int dpa_curlevel; /* The current level that we're reading */ + dnode_t *dpa_dnode; /* The dnode associated with the prefetch */ + zio_priority_t dpa_prio; /* The priority I/Os should be issued at. */ + zio_t *dpa_zio; /* The parent zio_t for all prefetches. */ + arc_flags_t dpa_aflags; /* Flags to pass to the final prefetch. */ +} dbuf_prefetch_arg_t; + +/* + * Actually issue the prefetch read for the block given. + */ +static void +dbuf_issue_final_prefetch(dbuf_prefetch_arg_t *dpa, blkptr_t *bp) +{ + ASSERT(!BP_IS_REDACTED(bp) || + dsl_dataset_feature_is_active( + dpa->dpa_dnode->dn_objset->os_dsl_dataset, + SPA_FEATURE_REDACTED_DATASETS)); + + if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp) || BP_IS_REDACTED(bp)) + return; + + int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE; + arc_flags_t aflags = + dpa->dpa_aflags | ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; + + /* dnodes are always read as raw and then converted later */ + if (BP_GET_TYPE(bp) == DMU_OT_DNODE && BP_IS_PROTECTED(bp) && + dpa->dpa_curlevel == 0) + zio_flags |= ZIO_FLAG_RAW; + + ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); + ASSERT3U(dpa->dpa_curlevel, ==, dpa->dpa_zb.zb_level); + ASSERT(dpa->dpa_zio != NULL); + (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, bp, NULL, NULL, + dpa->dpa_prio, zio_flags, &aflags, &dpa->dpa_zb); +} + +/* + * Called when an indirect block above our prefetch target is read in. This + * will either read in the next indirect block down the tree or issue the actual + * prefetch if the next block down is our target. + */ +static void +dbuf_prefetch_indirect_done(zio_t *zio, const zbookmark_phys_t *zb, + const blkptr_t *iobp, arc_buf_t *abuf, void *private) +{ + dbuf_prefetch_arg_t *dpa = private; + + ASSERT3S(dpa->dpa_zb.zb_level, <, dpa->dpa_curlevel); + ASSERT3S(dpa->dpa_curlevel, >, 0); + + if (abuf == NULL) { + ASSERT(zio == NULL || zio->io_error != 0); + kmem_free(dpa, sizeof (*dpa)); + return; + } + ASSERT(zio == NULL || zio->io_error == 0); + + /* + * The dpa_dnode is only valid if we are called with a NULL + * zio. This indicates that the arc_read() returned without + * first calling zio_read() to issue a physical read. Once + * a physical read is made the dpa_dnode must be invalidated + * as the locks guarding it may have been dropped. If the + * dpa_dnode is still valid, then we want to add it to the dbuf + * cache. To do so, we must hold the dbuf associated with the block + * we just prefetched, read its contents so that we associate it + * with an arc_buf_t, and then release it. + */ + if (zio != NULL) { + ASSERT3S(BP_GET_LEVEL(zio->io_bp), ==, dpa->dpa_curlevel); + if (zio->io_flags & ZIO_FLAG_RAW_COMPRESS) { + ASSERT3U(BP_GET_PSIZE(zio->io_bp), ==, zio->io_size); + } else { + ASSERT3U(BP_GET_LSIZE(zio->io_bp), ==, zio->io_size); + } + ASSERT3P(zio->io_spa, ==, dpa->dpa_spa); + + dpa->dpa_dnode = NULL; + } else if (dpa->dpa_dnode != NULL) { + uint64_t curblkid = dpa->dpa_zb.zb_blkid >> + (dpa->dpa_epbs * (dpa->dpa_curlevel - + dpa->dpa_zb.zb_level)); + dmu_buf_impl_t *db = dbuf_hold_level(dpa->dpa_dnode, + dpa->dpa_curlevel, curblkid, FTAG); + if (db == NULL) { + kmem_free(dpa, sizeof (*dpa)); + arc_buf_destroy(abuf, private); + return; + } + + (void) dbuf_read(db, NULL, + DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH | DB_RF_HAVESTRUCT); + dbuf_rele(db, FTAG); + } + + dpa->dpa_curlevel--; + uint64_t nextblkid = dpa->dpa_zb.zb_blkid >> + (dpa->dpa_epbs * (dpa->dpa_curlevel - dpa->dpa_zb.zb_level)); + blkptr_t *bp = ((blkptr_t *)abuf->b_data) + + P2PHASE(nextblkid, 1ULL << dpa->dpa_epbs); + + ASSERT(!BP_IS_REDACTED(bp) || + dsl_dataset_feature_is_active( + dpa->dpa_dnode->dn_objset->os_dsl_dataset, + SPA_FEATURE_REDACTED_DATASETS)); + if (BP_IS_HOLE(bp) || BP_IS_REDACTED(bp)) { + kmem_free(dpa, sizeof (*dpa)); + } else if (dpa->dpa_curlevel == dpa->dpa_zb.zb_level) { + ASSERT3U(nextblkid, ==, dpa->dpa_zb.zb_blkid); + dbuf_issue_final_prefetch(dpa, bp); + kmem_free(dpa, sizeof (*dpa)); + } else { + arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; + zbookmark_phys_t zb; + + /* flag if L2ARC eligible, l2arc_noprefetch then decides */ + if (dpa->dpa_aflags & ARC_FLAG_L2CACHE) + iter_aflags |= ARC_FLAG_L2CACHE; + + ASSERT3U(dpa->dpa_curlevel, ==, BP_GET_LEVEL(bp)); + + SET_BOOKMARK(&zb, dpa->dpa_zb.zb_objset, + dpa->dpa_zb.zb_object, dpa->dpa_curlevel, nextblkid); + + (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, + bp, dbuf_prefetch_indirect_done, dpa, dpa->dpa_prio, + ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, + &iter_aflags, &zb); + } + + arc_buf_destroy(abuf, private); +} + +/* + * Issue prefetch reads for the given block on the given level. If the indirect + * blocks above that block are not in memory, we will read them in + * asynchronously. As a result, this call never blocks waiting for a read to + * complete. Note that the prefetch might fail if the dataset is encrypted and + * the encryption key is unmapped before the IO completes. + */ +void +dbuf_prefetch(dnode_t *dn, int64_t level, uint64_t blkid, zio_priority_t prio, + arc_flags_t aflags) +{ + blkptr_t bp; + int epbs, nlevels, curlevel; + uint64_t curblkid; + + ASSERT(blkid != DMU_BONUS_BLKID); + ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); + + if (blkid > dn->dn_maxblkid) + return; + + if (level == 0 && dnode_block_freed(dn, blkid)) + return; + + /* + * This dnode hasn't been written to disk yet, so there's nothing to + * prefetch. + */ + nlevels = dn->dn_phys->dn_nlevels; + if (level >= nlevels || dn->dn_phys->dn_nblkptr == 0) + return; + + epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; + if (dn->dn_phys->dn_maxblkid < blkid << (epbs * level)) + return; + + dmu_buf_impl_t *db = dbuf_find(dn->dn_objset, dn->dn_object, + level, blkid); + if (db != NULL) { + mutex_exit(&db->db_mtx); + /* + * This dbuf already exists. It is either CACHED, or + * (we assume) about to be read or filled. + */ + return; + } + + /* + * Find the closest ancestor (indirect block) of the target block + * that is present in the cache. In this indirect block, we will + * find the bp that is at curlevel, curblkid. + */ + curlevel = level; + curblkid = blkid; + while (curlevel < nlevels - 1) { + int parent_level = curlevel + 1; + uint64_t parent_blkid = curblkid >> epbs; + dmu_buf_impl_t *db; + + if (dbuf_hold_impl(dn, parent_level, parent_blkid, + FALSE, TRUE, FTAG, &db) == 0) { + blkptr_t *bpp = db->db_buf->b_data; + bp = bpp[P2PHASE(curblkid, 1 << epbs)]; + dbuf_rele(db, FTAG); + break; + } + + curlevel = parent_level; + curblkid = parent_blkid; + } + + if (curlevel == nlevels - 1) { + /* No cached indirect blocks found. */ + ASSERT3U(curblkid, <, dn->dn_phys->dn_nblkptr); + bp = dn->dn_phys->dn_blkptr[curblkid]; + } + ASSERT(!BP_IS_REDACTED(&bp) || + dsl_dataset_feature_is_active(dn->dn_objset->os_dsl_dataset, + SPA_FEATURE_REDACTED_DATASETS)); + if (BP_IS_HOLE(&bp) || BP_IS_REDACTED(&bp)) + return; + + ASSERT3U(curlevel, ==, BP_GET_LEVEL(&bp)); + + zio_t *pio = zio_root(dmu_objset_spa(dn->dn_objset), NULL, NULL, + ZIO_FLAG_CANFAIL); + + dbuf_prefetch_arg_t *dpa = kmem_zalloc(sizeof (*dpa), KM_SLEEP); + dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; + SET_BOOKMARK(&dpa->dpa_zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, + dn->dn_object, level, blkid); + dpa->dpa_curlevel = curlevel; + dpa->dpa_prio = prio; + dpa->dpa_aflags = aflags; + dpa->dpa_spa = dn->dn_objset->os_spa; + dpa->dpa_dnode = dn; + dpa->dpa_epbs = epbs; + dpa->dpa_zio = pio; + + /* flag if L2ARC eligible, l2arc_noprefetch then decides */ + if (DNODE_LEVEL_IS_L2CACHEABLE(dn, level)) + dpa->dpa_aflags |= ARC_FLAG_L2CACHE; + + /* + * If we have the indirect just above us, no need to do the asynchronous + * prefetch chain; we'll just run the last step ourselves. If we're at + * a higher level, though, we want to issue the prefetches for all the + * indirect blocks asynchronously, so we can go on with whatever we were + * doing. + */ + if (curlevel == level) { + ASSERT3U(curblkid, ==, blkid); + dbuf_issue_final_prefetch(dpa, &bp); + kmem_free(dpa, sizeof (*dpa)); + } else { + arc_flags_t iter_aflags = ARC_FLAG_NOWAIT; + zbookmark_phys_t zb; + + /* flag if L2ARC eligible, l2arc_noprefetch then decides */ + if (DNODE_LEVEL_IS_L2CACHEABLE(dn, level)) + iter_aflags |= ARC_FLAG_L2CACHE; + + SET_BOOKMARK(&zb, ds != NULL ? ds->ds_object : DMU_META_OBJSET, + dn->dn_object, curlevel, curblkid); + (void) arc_read(dpa->dpa_zio, dpa->dpa_spa, + &bp, dbuf_prefetch_indirect_done, dpa, prio, + ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, + &iter_aflags, &zb); + } + /* + * We use pio here instead of dpa_zio since it's possible that + * dpa may have already been freed. + */ + zio_nowait(pio); +} + +/* + * Helper function for dbuf_hold_impl() to copy a buffer. Handles + * the case of encrypted, compressed and uncompressed buffers by + * allocating the new buffer, respectively, with arc_alloc_raw_buf(), + * arc_alloc_compressed_buf() or arc_alloc_buf().* + * + * NOTE: Declared noinline to avoid stack bloat in dbuf_hold_impl(). + */ +noinline static void +dbuf_hold_copy(dnode_t *dn, dmu_buf_impl_t *db) +{ + dbuf_dirty_record_t *dr = db->db_data_pending; + arc_buf_t *newdata, *data = dr->dt.dl.dr_data; + + newdata = dbuf_alloc_arcbuf_from_arcbuf(db, data); + dbuf_set_data(db, newdata); + rw_enter(&db->db_rwlock, RW_WRITER); + bcopy(data->b_data, db->db.db_data, arc_buf_size(data)); + rw_exit(&db->db_rwlock); +} + +/* + * Returns with db_holds incremented, and db_mtx not held. + * Note: dn_struct_rwlock must be held. + */ +int +dbuf_hold_impl(dnode_t *dn, uint8_t level, uint64_t blkid, + boolean_t fail_sparse, boolean_t fail_uncached, + void *tag, dmu_buf_impl_t **dbp) +{ + dmu_buf_impl_t *db, *parent = NULL; + + /* If the pool has been created, verify the tx_sync_lock is not held */ + spa_t *spa = dn->dn_objset->os_spa; + dsl_pool_t *dp = spa->spa_dsl_pool; + if (dp != NULL) { + ASSERT(!MUTEX_HELD(&dp->dp_tx.tx_sync_lock)); + } + + ASSERT(blkid != DMU_BONUS_BLKID); + ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); + ASSERT3U(dn->dn_nlevels, >, level); + + *dbp = NULL; + + /* dbuf_find() returns with db_mtx held */ + db = dbuf_find(dn->dn_objset, dn->dn_object, level, blkid); + + if (db == NULL) { + blkptr_t *bp = NULL; + int err; + + if (fail_uncached) + return (SET_ERROR(ENOENT)); + + ASSERT3P(parent, ==, NULL); + err = dbuf_findbp(dn, level, blkid, fail_sparse, &parent, &bp); + if (fail_sparse) { + if (err == 0 && bp && BP_IS_HOLE(bp)) + err = SET_ERROR(ENOENT); + if (err) { + if (parent) + dbuf_rele(parent, NULL); + return (err); + } + } + if (err && err != ENOENT) + return (err); + db = dbuf_create(dn, level, blkid, parent, bp); + } + + if (fail_uncached && db->db_state != DB_CACHED) { + mutex_exit(&db->db_mtx); + return (SET_ERROR(ENOENT)); + } + + if (db->db_buf != NULL) { + arc_buf_access(db->db_buf); + ASSERT3P(db->db.db_data, ==, db->db_buf->b_data); + } + + ASSERT(db->db_buf == NULL || arc_referenced(db->db_buf)); + + /* + * If this buffer is currently syncing out, and we are + * still referencing it from db_data, we need to make a copy + * of it in case we decide we want to dirty it again in this txg. + */ + if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID && + dn->dn_object != DMU_META_DNODE_OBJECT && + db->db_state == DB_CACHED && db->db_data_pending) { + dbuf_dirty_record_t *dr = db->db_data_pending; + if (dr->dt.dl.dr_data == db->db_buf) + dbuf_hold_copy(dn, db); + } + + if (multilist_link_active(&db->db_cache_link)) { + ASSERT(zfs_refcount_is_zero(&db->db_holds)); + ASSERT(db->db_caching_status == DB_DBUF_CACHE || + db->db_caching_status == DB_DBUF_METADATA_CACHE); + + multilist_remove(dbuf_caches[db->db_caching_status].cache, db); + (void) zfs_refcount_remove_many( + &dbuf_caches[db->db_caching_status].size, + db->db.db_size, db); + + if (db->db_caching_status == DB_DBUF_METADATA_CACHE) { + DBUF_STAT_BUMPDOWN(metadata_cache_count); + } else { + DBUF_STAT_BUMPDOWN(cache_levels[db->db_level]); + DBUF_STAT_BUMPDOWN(cache_count); + DBUF_STAT_DECR(cache_levels_bytes[db->db_level], + db->db.db_size); + } + db->db_caching_status = DB_NO_CACHE; + } + (void) zfs_refcount_add(&db->db_holds, tag); + DBUF_VERIFY(db); + mutex_exit(&db->db_mtx); + + /* NOTE: we can't rele the parent until after we drop the db_mtx */ + if (parent) + dbuf_rele(parent, NULL); + + ASSERT3P(DB_DNODE(db), ==, dn); + ASSERT3U(db->db_blkid, ==, blkid); + ASSERT3U(db->db_level, ==, level); + *dbp = db; + + return (0); +} + +dmu_buf_impl_t * +dbuf_hold(dnode_t *dn, uint64_t blkid, void *tag) +{ + return (dbuf_hold_level(dn, 0, blkid, tag)); +} + +dmu_buf_impl_t * +dbuf_hold_level(dnode_t *dn, int level, uint64_t blkid, void *tag) +{ + dmu_buf_impl_t *db; + int err = dbuf_hold_impl(dn, level, blkid, FALSE, FALSE, tag, &db); + return (err ? NULL : db); +} + +void +dbuf_create_bonus(dnode_t *dn) +{ + ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); + + ASSERT(dn->dn_bonus == NULL); + dn->dn_bonus = dbuf_create(dn, 0, DMU_BONUS_BLKID, dn->dn_dbuf, NULL); +} + +int +dbuf_spill_set_blksz(dmu_buf_t *db_fake, uint64_t blksz, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + if (db->db_blkid != DMU_SPILL_BLKID) + return (SET_ERROR(ENOTSUP)); + if (blksz == 0) + blksz = SPA_MINBLOCKSIZE; + ASSERT3U(blksz, <=, spa_maxblocksize(dmu_objset_spa(db->db_objset))); + blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE); + + dbuf_new_size(db, blksz, tx); + + return (0); +} + +void +dbuf_rm_spill(dnode_t *dn, dmu_tx_t *tx) +{ + dbuf_free_range(dn, DMU_SPILL_BLKID, DMU_SPILL_BLKID, tx); +} + +#pragma weak dmu_buf_add_ref = dbuf_add_ref +void +dbuf_add_ref(dmu_buf_impl_t *db, void *tag) +{ + int64_t holds = zfs_refcount_add(&db->db_holds, tag); + VERIFY3S(holds, >, 1); +} + +#pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref +boolean_t +dbuf_try_add_ref(dmu_buf_t *db_fake, objset_t *os, uint64_t obj, uint64_t blkid, + void *tag) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + dmu_buf_impl_t *found_db; + boolean_t result = B_FALSE; + + if (blkid == DMU_BONUS_BLKID) + found_db = dbuf_find_bonus(os, obj); + else + found_db = dbuf_find(os, obj, 0, blkid); + + if (found_db != NULL) { + if (db == found_db && dbuf_refcount(db) > db->db_dirtycnt) { + (void) zfs_refcount_add(&db->db_holds, tag); + result = B_TRUE; + } + mutex_exit(&found_db->db_mtx); + } + return (result); +} + +/* + * If you call dbuf_rele() you had better not be referencing the dnode handle + * unless you have some other direct or indirect hold on the dnode. (An indirect + * hold is a hold on one of the dnode's dbufs, including the bonus buffer.) + * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the + * dnode's parent dbuf evicting its dnode handles. + */ +void +dbuf_rele(dmu_buf_impl_t *db, void *tag) +{ + mutex_enter(&db->db_mtx); + dbuf_rele_and_unlock(db, tag, B_FALSE); +} + +void +dmu_buf_rele(dmu_buf_t *db, void *tag) +{ + dbuf_rele((dmu_buf_impl_t *)db, tag); +} + +/* + * dbuf_rele() for an already-locked dbuf. This is necessary to allow + * db_dirtycnt and db_holds to be updated atomically. The 'evicting' + * argument should be set if we are already in the dbuf-evicting code + * path, in which case we don't want to recursively evict. This allows us to + * avoid deeply nested stacks that would have a call flow similar to this: + * + * dbuf_rele()-->dbuf_rele_and_unlock()-->dbuf_evict_notify() + * ^ | + * | | + * +-----dbuf_destroy()<--dbuf_evict_one()<--------+ + * + */ +void +dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag, boolean_t evicting) +{ + int64_t holds; + uint64_t size; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + DBUF_VERIFY(db); + + /* + * Remove the reference to the dbuf before removing its hold on the + * dnode so we can guarantee in dnode_move() that a referenced bonus + * buffer has a corresponding dnode hold. + */ + holds = zfs_refcount_remove(&db->db_holds, tag); + ASSERT(holds >= 0); + + /* + * We can't freeze indirects if there is a possibility that they + * may be modified in the current syncing context. + */ + if (db->db_buf != NULL && + holds == (db->db_level == 0 ? db->db_dirtycnt : 0)) { + arc_buf_freeze(db->db_buf); + } + + if (holds == db->db_dirtycnt && + db->db_level == 0 && db->db_user_immediate_evict) + dbuf_evict_user(db); + + if (holds == 0) { + if (db->db_blkid == DMU_BONUS_BLKID) { + dnode_t *dn; + boolean_t evict_dbuf = db->db_pending_evict; + + /* + * If the dnode moves here, we cannot cross this + * barrier until the move completes. + */ + DB_DNODE_ENTER(db); + + dn = DB_DNODE(db); + atomic_dec_32(&dn->dn_dbufs_count); + + /* + * Decrementing the dbuf count means that the bonus + * buffer's dnode hold is no longer discounted in + * dnode_move(). The dnode cannot move until after + * the dnode_rele() below. + */ + DB_DNODE_EXIT(db); + + /* + * Do not reference db after its lock is dropped. + * Another thread may evict it. + */ + mutex_exit(&db->db_mtx); + + if (evict_dbuf) + dnode_evict_bonus(dn); + + dnode_rele(dn, db); + } else if (db->db_buf == NULL) { + /* + * This is a special case: we never associated this + * dbuf with any data allocated from the ARC. + */ + ASSERT(db->db_state == DB_UNCACHED || + db->db_state == DB_NOFILL); + dbuf_destroy(db); + } else if (arc_released(db->db_buf)) { + /* + * This dbuf has anonymous data associated with it. + */ + dbuf_destroy(db); + } else { + boolean_t do_arc_evict = B_FALSE; + blkptr_t bp; + spa_t *spa = dmu_objset_spa(db->db_objset); + + if (!DBUF_IS_CACHEABLE(db) && + db->db_blkptr != NULL && + !BP_IS_HOLE(db->db_blkptr) && + !BP_IS_EMBEDDED(db->db_blkptr)) { + do_arc_evict = B_TRUE; + bp = *db->db_blkptr; + } + + if (!DBUF_IS_CACHEABLE(db) || + db->db_pending_evict) { + dbuf_destroy(db); + } else if (!multilist_link_active(&db->db_cache_link)) { + ASSERT3U(db->db_caching_status, ==, + DB_NO_CACHE); + + dbuf_cached_state_t dcs = + dbuf_include_in_metadata_cache(db) ? + DB_DBUF_METADATA_CACHE : DB_DBUF_CACHE; + db->db_caching_status = dcs; + + multilist_insert(dbuf_caches[dcs].cache, db); + size = zfs_refcount_add_many( + &dbuf_caches[dcs].size, + db->db.db_size, db); + + if (dcs == DB_DBUF_METADATA_CACHE) { + DBUF_STAT_BUMP(metadata_cache_count); + DBUF_STAT_MAX( + metadata_cache_size_bytes_max, + size); + } else { + DBUF_STAT_BUMP( + cache_levels[db->db_level]); + DBUF_STAT_BUMP(cache_count); + DBUF_STAT_INCR( + cache_levels_bytes[db->db_level], + db->db.db_size); + DBUF_STAT_MAX(cache_size_bytes_max, + size); + } + mutex_exit(&db->db_mtx); + + if (dcs == DB_DBUF_CACHE && !evicting) + dbuf_evict_notify(size); + } + + if (do_arc_evict) + arc_freed(spa, &bp); + } + } else { + mutex_exit(&db->db_mtx); + } + +} + +#pragma weak dmu_buf_refcount = dbuf_refcount +uint64_t +dbuf_refcount(dmu_buf_impl_t *db) +{ + return (zfs_refcount_count(&db->db_holds)); +} + +uint64_t +dmu_buf_user_refcount(dmu_buf_t *db_fake) +{ + uint64_t holds; + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + mutex_enter(&db->db_mtx); + ASSERT3U(zfs_refcount_count(&db->db_holds), >=, db->db_dirtycnt); + holds = zfs_refcount_count(&db->db_holds) - db->db_dirtycnt; + mutex_exit(&db->db_mtx); + + return (holds); +} + +void * +dmu_buf_replace_user(dmu_buf_t *db_fake, dmu_buf_user_t *old_user, + dmu_buf_user_t *new_user) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + mutex_enter(&db->db_mtx); + dbuf_verify_user(db, DBVU_NOT_EVICTING); + if (db->db_user == old_user) + db->db_user = new_user; + else + old_user = db->db_user; + dbuf_verify_user(db, DBVU_NOT_EVICTING); + mutex_exit(&db->db_mtx); + + return (old_user); +} + +void * +dmu_buf_set_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) +{ + return (dmu_buf_replace_user(db_fake, NULL, user)); +} + +void * +dmu_buf_set_user_ie(dmu_buf_t *db_fake, dmu_buf_user_t *user) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + db->db_user_immediate_evict = TRUE; + return (dmu_buf_set_user(db_fake, user)); +} + +void * +dmu_buf_remove_user(dmu_buf_t *db_fake, dmu_buf_user_t *user) +{ + return (dmu_buf_replace_user(db_fake, user, NULL)); +} + +void * +dmu_buf_get_user(dmu_buf_t *db_fake) +{ + dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake; + + dbuf_verify_user(db, DBVU_NOT_EVICTING); + return (db->db_user); +} + +void +dmu_buf_user_evict_wait() +{ + taskq_wait(dbu_evict_taskq); +} + +blkptr_t * +dmu_buf_get_blkptr(dmu_buf_t *db) +{ + dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; + return (dbi->db_blkptr); +} + +objset_t * +dmu_buf_get_objset(dmu_buf_t *db) +{ + dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; + return (dbi->db_objset); +} + +dnode_t * +dmu_buf_dnode_enter(dmu_buf_t *db) +{ + dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; + DB_DNODE_ENTER(dbi); + return (DB_DNODE(dbi)); +} + +void +dmu_buf_dnode_exit(dmu_buf_t *db) +{ + dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db; + DB_DNODE_EXIT(dbi); +} + +static void +dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db) +{ + /* ASSERT(dmu_tx_is_syncing(tx) */ + ASSERT(MUTEX_HELD(&db->db_mtx)); + + if (db->db_blkptr != NULL) + return; + + if (db->db_blkid == DMU_SPILL_BLKID) { + db->db_blkptr = DN_SPILL_BLKPTR(dn->dn_phys); + BP_ZERO(db->db_blkptr); + return; + } + if (db->db_level == dn->dn_phys->dn_nlevels-1) { + /* + * This buffer was allocated at a time when there was + * no available blkptrs from the dnode, or it was + * inappropriate to hook it in (i.e., nlevels mismatch). + */ + ASSERT(db->db_blkid < dn->dn_phys->dn_nblkptr); + ASSERT(db->db_parent == NULL); + db->db_parent = dn->dn_dbuf; + db->db_blkptr = &dn->dn_phys->dn_blkptr[db->db_blkid]; + DBUF_VERIFY(db); + } else { + dmu_buf_impl_t *parent = db->db_parent; + int epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; + + ASSERT(dn->dn_phys->dn_nlevels > 1); + if (parent == NULL) { + mutex_exit(&db->db_mtx); + rw_enter(&dn->dn_struct_rwlock, RW_READER); + parent = dbuf_hold_level(dn, db->db_level + 1, + db->db_blkid >> epbs, db); + rw_exit(&dn->dn_struct_rwlock); + mutex_enter(&db->db_mtx); + db->db_parent = parent; + } + db->db_blkptr = (blkptr_t *)parent->db.db_data + + (db->db_blkid & ((1ULL << epbs) - 1)); + DBUF_VERIFY(db); + } +} + +static void +dbuf_sync_bonus(dbuf_dirty_record_t *dr, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + void *data = dr->dt.dl.dr_data; + + ASSERT0(db->db_level); + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT(DB_DNODE_HELD(db)); + ASSERT(db->db_blkid == DMU_BONUS_BLKID); + ASSERT(data != NULL); + + dnode_t *dn = DB_DNODE(db); + ASSERT3U(DN_MAX_BONUS_LEN(dn->dn_phys), <=, + DN_SLOTS_TO_BONUSLEN(dn->dn_phys->dn_extra_slots + 1)); + bcopy(data, DN_BONUS(dn->dn_phys), DN_MAX_BONUS_LEN(dn->dn_phys)); + DB_DNODE_EXIT(db); + + dbuf_sync_leaf_verify_bonus_dnode(dr); + + dbuf_undirty_bonus(dr); + dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg, B_FALSE); +} + +/* + * When syncing out a blocks of dnodes, adjust the block to deal with + * encryption. Normally, we make sure the block is decrypted before writing + * it. If we have crypt params, then we are writing a raw (encrypted) block, + * from a raw receive. In this case, set the ARC buf's crypt params so + * that the BP will be filled with the correct byteorder, salt, iv, and mac. + */ +static void +dbuf_prepare_encrypted_dnode_leaf(dbuf_dirty_record_t *dr) +{ + int err; + dmu_buf_impl_t *db = dr->dr_dbuf; + + ASSERT(MUTEX_HELD(&db->db_mtx)); + ASSERT3U(db->db.db_object, ==, DMU_META_DNODE_OBJECT); + ASSERT3U(db->db_level, ==, 0); + + if (!db->db_objset->os_raw_receive && arc_is_encrypted(db->db_buf)) { + zbookmark_phys_t zb; + + /* + * Unfortunately, there is currently no mechanism for + * syncing context to handle decryption errors. An error + * here is only possible if an attacker maliciously + * changed a dnode block and updated the associated + * checksums going up the block tree. + */ + SET_BOOKMARK(&zb, dmu_objset_id(db->db_objset), + db->db.db_object, db->db_level, db->db_blkid); + err = arc_untransform(db->db_buf, db->db_objset->os_spa, + &zb, B_TRUE); + if (err) + panic("Invalid dnode block MAC"); + } else if (dr->dt.dl.dr_has_raw_params) { + (void) arc_release(dr->dt.dl.dr_data, db); + arc_convert_to_raw(dr->dt.dl.dr_data, + dmu_objset_id(db->db_objset), + dr->dt.dl.dr_byteorder, DMU_OT_DNODE, + dr->dt.dl.dr_salt, dr->dt.dl.dr_iv, dr->dt.dl.dr_mac); + } +} + +/* + * dbuf_sync_indirect() is called recursively from dbuf_sync_list() so it + * is critical the we not allow the compiler to inline this function in to + * dbuf_sync_list() thereby drastically bloating the stack usage. + */ +noinline static void +dbuf_sync_indirect(dbuf_dirty_record_t *dr, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + dnode_t *dn; + zio_t *zio; + + ASSERT(dmu_tx_is_syncing(tx)); + + dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); + + mutex_enter(&db->db_mtx); + + ASSERT(db->db_level > 0); + DBUF_VERIFY(db); + + /* Read the block if it hasn't been read yet. */ + if (db->db_buf == NULL) { + mutex_exit(&db->db_mtx); + (void) dbuf_read(db, NULL, DB_RF_MUST_SUCCEED); + mutex_enter(&db->db_mtx); + } + ASSERT3U(db->db_state, ==, DB_CACHED); + ASSERT(db->db_buf != NULL); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + /* Indirect block size must match what the dnode thinks it is. */ + ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); + dbuf_check_blkptr(dn, db); + DB_DNODE_EXIT(db); + + /* Provide the pending dirty record to child dbufs */ + db->db_data_pending = dr; + + mutex_exit(&db->db_mtx); + + dbuf_write(dr, db->db_buf, tx); + + zio = dr->dr_zio; + mutex_enter(&dr->dt.di.dr_mtx); + dbuf_sync_list(&dr->dt.di.dr_children, db->db_level - 1, tx); + ASSERT(list_head(&dr->dt.di.dr_children) == NULL); + mutex_exit(&dr->dt.di.dr_mtx); + zio_nowait(zio); +} + +/* + * Verify that the size of the data in our bonus buffer does not exceed + * its recorded size. + * + * The purpose of this verification is to catch any cases in development + * where the size of a phys structure (i.e space_map_phys_t) grows and, + * due to incorrect feature management, older pools expect to read more + * data even though they didn't actually write it to begin with. + * + * For a example, this would catch an error in the feature logic where we + * open an older pool and we expect to write the space map histogram of + * a space map with size SPACE_MAP_SIZE_V0. + */ +static void +dbuf_sync_leaf_verify_bonus_dnode(dbuf_dirty_record_t *dr) +{ +#ifdef ZFS_DEBUG + dnode_t *dn = DB_DNODE(dr->dr_dbuf); + + /* + * Encrypted bonus buffers can have data past their bonuslen. + * Skip the verification of these blocks. + */ + if (DMU_OT_IS_ENCRYPTED(dn->dn_bonustype)) + return; + + uint16_t bonuslen = dn->dn_phys->dn_bonuslen; + uint16_t maxbonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); + ASSERT3U(bonuslen, <=, maxbonuslen); + + arc_buf_t *datap = dr->dt.dl.dr_data; + char *datap_end = ((char *)datap) + bonuslen; + char *datap_max = ((char *)datap) + maxbonuslen; + + /* ensure that everything is zero after our data */ + for (; datap_end < datap_max; datap_end++) + ASSERT(*datap_end == 0); +#endif +} + +/* + * dbuf_sync_leaf() is called recursively from dbuf_sync_list() so it is + * critical the we not allow the compiler to inline this function in to + * dbuf_sync_list() thereby drastically bloating the stack usage. + */ +noinline static void +dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx) +{ + arc_buf_t **datap = &dr->dt.dl.dr_data; + dmu_buf_impl_t *db = dr->dr_dbuf; + dnode_t *dn; + objset_t *os; + uint64_t txg = tx->tx_txg; + + ASSERT(dmu_tx_is_syncing(tx)); + + dprintf_dbuf_bp(db, db->db_blkptr, "blkptr=%p", db->db_blkptr); + + mutex_enter(&db->db_mtx); + /* + * To be synced, we must be dirtied. But we + * might have been freed after the dirty. + */ + if (db->db_state == DB_UNCACHED) { + /* This buffer has been freed since it was dirtied */ + ASSERT(db->db.db_data == NULL); + } else if (db->db_state == DB_FILL) { + /* This buffer was freed and is now being re-filled */ + ASSERT(db->db.db_data != dr->dt.dl.dr_data); + } else { + ASSERT(db->db_state == DB_CACHED || db->db_state == DB_NOFILL); + } + DBUF_VERIFY(db); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + + if (db->db_blkid == DMU_SPILL_BLKID) { + mutex_enter(&dn->dn_mtx); + if (!(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) { + /* + * In the previous transaction group, the bonus buffer + * was entirely used to store the attributes for the + * dnode which overrode the dn_spill field. However, + * when adding more attributes to the file a spill + * block was required to hold the extra attributes. + * + * Make sure to clear the garbage left in the dn_spill + * field from the previous attributes in the bonus + * buffer. Otherwise, after writing out the spill + * block to the new allocated dva, it will free + * the old block pointed to by the invalid dn_spill. + */ + db->db_blkptr = NULL; + } + dn->dn_phys->dn_flags |= DNODE_FLAG_SPILL_BLKPTR; + mutex_exit(&dn->dn_mtx); + } + + /* + * If this is a bonus buffer, simply copy the bonus data into the + * dnode. It will be written out when the dnode is synced (and it + * will be synced, since it must have been dirty for dbuf_sync to + * be called). + */ + if (db->db_blkid == DMU_BONUS_BLKID) { + ASSERT(dr->dr_dbuf == db); + dbuf_sync_bonus(dr, tx); + return; + } + + os = dn->dn_objset; + + /* + * This function may have dropped the db_mtx lock allowing a dmu_sync + * operation to sneak in. As a result, we need to ensure that we + * don't check the dr_override_state until we have returned from + * dbuf_check_blkptr. + */ + dbuf_check_blkptr(dn, db); + + /* + * If this buffer is in the middle of an immediate write, + * wait for the synchronous IO to complete. + */ + while (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) { + ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT); + cv_wait(&db->db_changed, &db->db_mtx); + ASSERT(dr->dt.dl.dr_override_state != DR_NOT_OVERRIDDEN); + } + + /* + * If this is a dnode block, ensure it is appropriately encrypted + * or decrypted, depending on what we are writing to it this txg. + */ + if (os->os_encrypted && dn->dn_object == DMU_META_DNODE_OBJECT) + dbuf_prepare_encrypted_dnode_leaf(dr); + + if (db->db_state != DB_NOFILL && + dn->dn_object != DMU_META_DNODE_OBJECT && + zfs_refcount_count(&db->db_holds) > 1 && + dr->dt.dl.dr_override_state != DR_OVERRIDDEN && + *datap == db->db_buf) { + /* + * If this buffer is currently "in use" (i.e., there + * are active holds and db_data still references it), + * then make a copy before we start the write so that + * any modifications from the open txg will not leak + * into this write. + * + * NOTE: this copy does not need to be made for + * objects only modified in the syncing context (e.g. + * DNONE_DNODE blocks). + */ + *datap = dbuf_alloc_arcbuf_from_arcbuf(db, db->db_buf); + bcopy(db->db.db_data, (*datap)->b_data, arc_buf_size(*datap)); + } + db->db_data_pending = dr; + + mutex_exit(&db->db_mtx); + + dbuf_write(dr, *datap, tx); + + ASSERT(!list_link_active(&dr->dr_dirty_node)); + if (dn->dn_object == DMU_META_DNODE_OBJECT) { + list_insert_tail(&dn->dn_dirty_records[txg & TXG_MASK], dr); + DB_DNODE_EXIT(db); + } else { + /* + * Although zio_nowait() does not "wait for an IO", it does + * initiate the IO. If this is an empty write it seems plausible + * that the IO could actually be completed before the nowait + * returns. We need to DB_DNODE_EXIT() first in case + * zio_nowait() invalidates the dbuf. + */ + DB_DNODE_EXIT(db); + zio_nowait(dr->dr_zio); + } +} + +void +dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx) +{ + dbuf_dirty_record_t *dr; + + while ((dr = list_head(list))) { + if (dr->dr_zio != NULL) { + /* + * If we find an already initialized zio then we + * are processing the meta-dnode, and we have finished. + * The dbufs for all dnodes are put back on the list + * during processing, so that we can zio_wait() + * these IOs after initiating all child IOs. + */ + ASSERT3U(dr->dr_dbuf->db.db_object, ==, + DMU_META_DNODE_OBJECT); + break; + } + if (dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && + dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) { + VERIFY3U(dr->dr_dbuf->db_level, ==, level); + } + list_remove(list, dr); + if (dr->dr_dbuf->db_level > 0) + dbuf_sync_indirect(dr, tx); + else + dbuf_sync_leaf(dr, tx); + } +} + +/* ARGSUSED */ +static void +dbuf_write_ready(zio_t *zio, arc_buf_t *buf, void *vdb) +{ + dmu_buf_impl_t *db = vdb; + dnode_t *dn; + blkptr_t *bp = zio->io_bp; + blkptr_t *bp_orig = &zio->io_bp_orig; + spa_t *spa = zio->io_spa; + int64_t delta; + uint64_t fill = 0; + int i; + + ASSERT3P(db->db_blkptr, !=, NULL); + ASSERT3P(&db->db_data_pending->dr_bp_copy, ==, bp); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + delta = bp_get_dsize_sync(spa, bp) - bp_get_dsize_sync(spa, bp_orig); + dnode_diduse_space(dn, delta - zio->io_prev_space_delta); + zio->io_prev_space_delta = delta; + + if (bp->blk_birth != 0) { + ASSERT((db->db_blkid != DMU_SPILL_BLKID && + BP_GET_TYPE(bp) == dn->dn_type) || + (db->db_blkid == DMU_SPILL_BLKID && + BP_GET_TYPE(bp) == dn->dn_bonustype) || + BP_IS_EMBEDDED(bp)); + ASSERT(BP_GET_LEVEL(bp) == db->db_level); + } + + mutex_enter(&db->db_mtx); + +#ifdef ZFS_DEBUG + if (db->db_blkid == DMU_SPILL_BLKID) { + ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); + ASSERT(!(BP_IS_HOLE(bp)) && + db->db_blkptr == DN_SPILL_BLKPTR(dn->dn_phys)); + } +#endif + + if (db->db_level == 0) { + mutex_enter(&dn->dn_mtx); + if (db->db_blkid > dn->dn_phys->dn_maxblkid && + db->db_blkid != DMU_SPILL_BLKID) { + ASSERT0(db->db_objset->os_raw_receive); + dn->dn_phys->dn_maxblkid = db->db_blkid; + } + mutex_exit(&dn->dn_mtx); + + if (dn->dn_type == DMU_OT_DNODE) { + i = 0; + while (i < db->db.db_size) { + dnode_phys_t *dnp = + (void *)(((char *)db->db.db_data) + i); + + i += DNODE_MIN_SIZE; + if (dnp->dn_type != DMU_OT_NONE) { + fill++; + i += dnp->dn_extra_slots * + DNODE_MIN_SIZE; + } + } + } else { + if (BP_IS_HOLE(bp)) { + fill = 0; + } else { + fill = 1; + } + } + } else { + blkptr_t *ibp = db->db.db_data; + ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift); + for (i = db->db.db_size >> SPA_BLKPTRSHIFT; i > 0; i--, ibp++) { + if (BP_IS_HOLE(ibp)) + continue; + fill += BP_GET_FILL(ibp); + } + } + DB_DNODE_EXIT(db); + + if (!BP_IS_EMBEDDED(bp)) + BP_SET_FILL(bp, fill); + + mutex_exit(&db->db_mtx); + + db_lock_type_t dblt = dmu_buf_lock_parent(db, RW_WRITER, FTAG); + *db->db_blkptr = *bp; + dmu_buf_unlock_parent(db, dblt, FTAG); +} + +/* ARGSUSED */ +/* + * This function gets called just prior to running through the compression + * stage of the zio pipeline. If we're an indirect block comprised of only + * holes, then we want this indirect to be compressed away to a hole. In + * order to do that we must zero out any information about the holes that + * this indirect points to prior to before we try to compress it. + */ +static void +dbuf_write_children_ready(zio_t *zio, arc_buf_t *buf, void *vdb) +{ + dmu_buf_impl_t *db = vdb; + dnode_t *dn; + blkptr_t *bp; + unsigned int epbs, i; + + ASSERT3U(db->db_level, >, 0); + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; + ASSERT3U(epbs, <, 31); + + /* Determine if all our children are holes */ + for (i = 0, bp = db->db.db_data; i < 1ULL << epbs; i++, bp++) { + if (!BP_IS_HOLE(bp)) + break; + } + + /* + * If all the children are holes, then zero them all out so that + * we may get compressed away. + */ + if (i == 1ULL << epbs) { + /* + * We only found holes. Grab the rwlock to prevent + * anybody from reading the blocks we're about to + * zero out. + */ + rw_enter(&db->db_rwlock, RW_WRITER); + bzero(db->db.db_data, db->db.db_size); + rw_exit(&db->db_rwlock); + } + DB_DNODE_EXIT(db); +} + +/* + * The SPA will call this callback several times for each zio - once + * for every physical child i/o (zio->io_phys_children times). This + * allows the DMU to monitor the progress of each logical i/o. For example, + * there may be 2 copies of an indirect block, or many fragments of a RAID-Z + * block. There may be a long delay before all copies/fragments are completed, + * so this callback allows us to retire dirty space gradually, as the physical + * i/os complete. + */ +/* ARGSUSED */ +static void +dbuf_write_physdone(zio_t *zio, arc_buf_t *buf, void *arg) +{ + dmu_buf_impl_t *db = arg; + objset_t *os = db->db_objset; + dsl_pool_t *dp = dmu_objset_pool(os); + dbuf_dirty_record_t *dr; + int delta = 0; + + dr = db->db_data_pending; + ASSERT3U(dr->dr_txg, ==, zio->io_txg); + + /* + * The callback will be called io_phys_children times. Retire one + * portion of our dirty space each time we are called. Any rounding + * error will be cleaned up by dbuf_write_done(). + */ + delta = dr->dr_accounted / zio->io_phys_children; + dsl_pool_undirty_space(dp, delta, zio->io_txg); +} + +/* ARGSUSED */ +static void +dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb) +{ + dmu_buf_impl_t *db = vdb; + blkptr_t *bp_orig = &zio->io_bp_orig; + blkptr_t *bp = db->db_blkptr; + objset_t *os = db->db_objset; + dmu_tx_t *tx = os->os_synctx; + dbuf_dirty_record_t *dr; + + ASSERT0(zio->io_error); + ASSERT(db->db_blkptr == bp); + + /* + * For nopwrites and rewrites we ensure that the bp matches our + * original and bypass all the accounting. + */ + if (zio->io_flags & (ZIO_FLAG_IO_REWRITE | ZIO_FLAG_NOPWRITE)) { + ASSERT(BP_EQUAL(bp, bp_orig)); + } else { + dsl_dataset_t *ds = os->os_dsl_dataset; + (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE); + dsl_dataset_block_born(ds, bp, tx); + } + + mutex_enter(&db->db_mtx); + + DBUF_VERIFY(db); + + dr = db->db_data_pending; + ASSERT(!list_link_active(&dr->dr_dirty_node)); + ASSERT(dr->dr_dbuf == db); + ASSERT(list_next(&db->db_dirty_records, dr) == NULL); + list_remove(&db->db_dirty_records, dr); + +#ifdef ZFS_DEBUG + if (db->db_blkid == DMU_SPILL_BLKID) { + dnode_t *dn; + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + ASSERT(dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR); + ASSERT(!(BP_IS_HOLE(db->db_blkptr)) && + db->db_blkptr == DN_SPILL_BLKPTR(dn->dn_phys)); + DB_DNODE_EXIT(db); + } +#endif + + if (db->db_level == 0) { + ASSERT(db->db_blkid != DMU_BONUS_BLKID); + ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN); + if (db->db_state != DB_NOFILL) { + if (dr->dt.dl.dr_data != db->db_buf) + arc_buf_destroy(dr->dt.dl.dr_data, db); + } + } else { + dnode_t *dn; + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + ASSERT(list_head(&dr->dt.di.dr_children) == NULL); + ASSERT3U(db->db.db_size, ==, 1 << dn->dn_phys->dn_indblkshift); + if (!BP_IS_HOLE(db->db_blkptr)) { + int epbs __maybe_unused = dn->dn_phys->dn_indblkshift - + SPA_BLKPTRSHIFT; + ASSERT3U(db->db_blkid, <=, + dn->dn_phys->dn_maxblkid >> (db->db_level * epbs)); + ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==, + db->db.db_size); + } + DB_DNODE_EXIT(db); + mutex_destroy(&dr->dt.di.dr_mtx); + list_destroy(&dr->dt.di.dr_children); + } + + cv_broadcast(&db->db_changed); + ASSERT(db->db_dirtycnt > 0); + db->db_dirtycnt -= 1; + db->db_data_pending = NULL; + dbuf_rele_and_unlock(db, (void *)(uintptr_t)tx->tx_txg, B_FALSE); + + /* + * If we didn't do a physical write in this ZIO and we + * still ended up here, it means that the space of the + * dbuf that we just released (and undirtied) above hasn't + * been marked as undirtied in the pool's accounting. + * + * Thus, we undirty that space in the pool's view of the + * world here. For physical writes this type of update + * happens in dbuf_write_physdone(). + * + * If we did a physical write, cleanup any rounding errors + * that came up due to writing multiple copies of a block + * on disk [see dbuf_write_physdone()]. + */ + if (zio->io_phys_children == 0) { + dsl_pool_undirty_space(dmu_objset_pool(os), + dr->dr_accounted, zio->io_txg); + } else { + dsl_pool_undirty_space(dmu_objset_pool(os), + dr->dr_accounted % zio->io_phys_children, zio->io_txg); + } + + kmem_free(dr, sizeof (dbuf_dirty_record_t)); +} + +static void +dbuf_write_nofill_ready(zio_t *zio) +{ + dbuf_write_ready(zio, NULL, zio->io_private); +} + +static void +dbuf_write_nofill_done(zio_t *zio) +{ + dbuf_write_done(zio, NULL, zio->io_private); +} + +static void +dbuf_write_override_ready(zio_t *zio) +{ + dbuf_dirty_record_t *dr = zio->io_private; + dmu_buf_impl_t *db = dr->dr_dbuf; + + dbuf_write_ready(zio, NULL, db); +} + +static void +dbuf_write_override_done(zio_t *zio) +{ + dbuf_dirty_record_t *dr = zio->io_private; + dmu_buf_impl_t *db = dr->dr_dbuf; + blkptr_t *obp = &dr->dt.dl.dr_overridden_by; + + mutex_enter(&db->db_mtx); + if (!BP_EQUAL(zio->io_bp, obp)) { + if (!BP_IS_HOLE(obp)) + dsl_free(spa_get_dsl(zio->io_spa), zio->io_txg, obp); + arc_release(dr->dt.dl.dr_data, db); + } + mutex_exit(&db->db_mtx); + + dbuf_write_done(zio, NULL, db); + + if (zio->io_abd != NULL) + abd_put(zio->io_abd); +} + +typedef struct dbuf_remap_impl_callback_arg { + objset_t *drica_os; + uint64_t drica_blk_birth; + dmu_tx_t *drica_tx; +} dbuf_remap_impl_callback_arg_t; + +static void +dbuf_remap_impl_callback(uint64_t vdev, uint64_t offset, uint64_t size, + void *arg) +{ + dbuf_remap_impl_callback_arg_t *drica = arg; + objset_t *os = drica->drica_os; + spa_t *spa = dmu_objset_spa(os); + dmu_tx_t *tx = drica->drica_tx; + + ASSERT(dsl_pool_sync_context(spa_get_dsl(spa))); + + if (os == spa_meta_objset(spa)) { + spa_vdev_indirect_mark_obsolete(spa, vdev, offset, size, tx); + } else { + dsl_dataset_block_remapped(dmu_objset_ds(os), vdev, offset, + size, drica->drica_blk_birth, tx); + } +} + +static void +dbuf_remap_impl(dnode_t *dn, blkptr_t *bp, krwlock_t *rw, dmu_tx_t *tx) +{ + blkptr_t bp_copy = *bp; + spa_t *spa = dmu_objset_spa(dn->dn_objset); + dbuf_remap_impl_callback_arg_t drica; + + ASSERT(dsl_pool_sync_context(spa_get_dsl(spa))); + + drica.drica_os = dn->dn_objset; + drica.drica_blk_birth = bp->blk_birth; + drica.drica_tx = tx; + if (spa_remap_blkptr(spa, &bp_copy, dbuf_remap_impl_callback, + &drica)) { + /* + * If the blkptr being remapped is tracked by a livelist, + * then we need to make sure the livelist reflects the update. + * First, cancel out the old blkptr by appending a 'FREE' + * entry. Next, add an 'ALLOC' to track the new version. This + * way we avoid trying to free an inaccurate blkptr at delete. + * Note that embedded blkptrs are not tracked in livelists. + */ + if (dn->dn_objset != spa_meta_objset(spa)) { + dsl_dataset_t *ds = dmu_objset_ds(dn->dn_objset); + if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist) && + bp->blk_birth > ds->ds_dir->dd_origin_txg) { + ASSERT(!BP_IS_EMBEDDED(bp)); + ASSERT(dsl_dir_is_clone(ds->ds_dir)); + ASSERT(spa_feature_is_enabled(spa, + SPA_FEATURE_LIVELIST)); + bplist_append(&ds->ds_dir->dd_pending_frees, + bp); + bplist_append(&ds->ds_dir->dd_pending_allocs, + &bp_copy); + } + } + + /* + * The db_rwlock prevents dbuf_read_impl() from + * dereferencing the BP while we are changing it. To + * avoid lock contention, only grab it when we are actually + * changing the BP. + */ + if (rw != NULL) + rw_enter(rw, RW_WRITER); + *bp = bp_copy; + if (rw != NULL) + rw_exit(rw); + } +} + +/* + * Remap any existing BP's to concrete vdevs, if possible. + */ +static void +dbuf_remap(dnode_t *dn, dmu_buf_impl_t *db, dmu_tx_t *tx) +{ + spa_t *spa = dmu_objset_spa(db->db_objset); + ASSERT(dsl_pool_sync_context(spa_get_dsl(spa))); + + if (!spa_feature_is_active(spa, SPA_FEATURE_DEVICE_REMOVAL)) + return; + + if (db->db_level > 0) { + blkptr_t *bp = db->db.db_data; + for (int i = 0; i < db->db.db_size >> SPA_BLKPTRSHIFT; i++) { + dbuf_remap_impl(dn, &bp[i], &db->db_rwlock, tx); + } + } else if (db->db.db_object == DMU_META_DNODE_OBJECT) { + dnode_phys_t *dnp = db->db.db_data; + ASSERT3U(db->db_dnode_handle->dnh_dnode->dn_type, ==, + DMU_OT_DNODE); + for (int i = 0; i < db->db.db_size >> DNODE_SHIFT; + i += dnp[i].dn_extra_slots + 1) { + for (int j = 0; j < dnp[i].dn_nblkptr; j++) { + krwlock_t *lock = (dn->dn_dbuf == NULL ? NULL : + &dn->dn_dbuf->db_rwlock); + dbuf_remap_impl(dn, &dnp[i].dn_blkptr[j], lock, + tx); + } + } + } +} + + +/* Issue I/O to commit a dirty buffer to disk. */ +static void +dbuf_write(dbuf_dirty_record_t *dr, arc_buf_t *data, dmu_tx_t *tx) +{ + dmu_buf_impl_t *db = dr->dr_dbuf; + dnode_t *dn; + objset_t *os; + dmu_buf_impl_t *parent = db->db_parent; + uint64_t txg = tx->tx_txg; + zbookmark_phys_t zb; + zio_prop_t zp; + zio_t *pio; /* parent I/O */ + int wp_flag = 0; + + ASSERT(dmu_tx_is_syncing(tx)); + + DB_DNODE_ENTER(db); + dn = DB_DNODE(db); + os = dn->dn_objset; + + if (db->db_state != DB_NOFILL) { + if (db->db_level > 0 || dn->dn_type == DMU_OT_DNODE) { + /* + * Private object buffers are released here rather + * than in dbuf_dirty() since they are only modified + * in the syncing context and we don't want the + * overhead of making multiple copies of the data. + */ + if (BP_IS_HOLE(db->db_blkptr)) { + arc_buf_thaw(data); + } else { + dbuf_release_bp(db); + } + dbuf_remap(dn, db, tx); + } + } + + if (parent != dn->dn_dbuf) { + /* Our parent is an indirect block. */ + /* We have a dirty parent that has been scheduled for write. */ + ASSERT(parent && parent->db_data_pending); + /* Our parent's buffer is one level closer to the dnode. */ + ASSERT(db->db_level == parent->db_level-1); + /* + * We're about to modify our parent's db_data by modifying + * our block pointer, so the parent must be released. + */ + ASSERT(arc_released(parent->db_buf)); + pio = parent->db_data_pending->dr_zio; + } else { + /* Our parent is the dnode itself. */ + ASSERT((db->db_level == dn->dn_phys->dn_nlevels-1 && + db->db_blkid != DMU_SPILL_BLKID) || + (db->db_blkid == DMU_SPILL_BLKID && db->db_level == 0)); + if (db->db_blkid != DMU_SPILL_BLKID) + ASSERT3P(db->db_blkptr, ==, + &dn->dn_phys->dn_blkptr[db->db_blkid]); + pio = dn->dn_zio; + } + + ASSERT(db->db_level == 0 || data == db->db_buf); + ASSERT3U(db->db_blkptr->blk_birth, <=, txg); + ASSERT(pio); + + SET_BOOKMARK(&zb, os->os_dsl_dataset ? + os->os_dsl_dataset->ds_object : DMU_META_OBJSET, + db->db.db_object, db->db_level, db->db_blkid); + + if (db->db_blkid == DMU_SPILL_BLKID) + wp_flag = WP_SPILL; + wp_flag |= (db->db_state == DB_NOFILL) ? WP_NOFILL : 0; + + dmu_write_policy(os, dn, db->db_level, wp_flag, &zp); + DB_DNODE_EXIT(db); + + /* + * We copy the blkptr now (rather than when we instantiate the dirty + * record), because its value can change between open context and + * syncing context. We do not need to hold dn_struct_rwlock to read + * db_blkptr because we are in syncing context. + */ + dr->dr_bp_copy = *db->db_blkptr; + + if (db->db_level == 0 && + dr->dt.dl.dr_override_state == DR_OVERRIDDEN) { + /* + * The BP for this block has been provided by open context + * (by dmu_sync() or dmu_buf_write_embedded()). + */ + abd_t *contents = (data != NULL) ? + abd_get_from_buf(data->b_data, arc_buf_size(data)) : NULL; + + dr->dr_zio = zio_write(pio, os->os_spa, txg, &dr->dr_bp_copy, + contents, db->db.db_size, db->db.db_size, &zp, + dbuf_write_override_ready, NULL, NULL, + dbuf_write_override_done, + dr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb); + mutex_enter(&db->db_mtx); + dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN; + zio_write_override(dr->dr_zio, &dr->dt.dl.dr_overridden_by, + dr->dt.dl.dr_copies, dr->dt.dl.dr_nopwrite); + mutex_exit(&db->db_mtx); + } else if (db->db_state == DB_NOFILL) { + ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF || + zp.zp_checksum == ZIO_CHECKSUM_NOPARITY); + dr->dr_zio = zio_write(pio, os->os_spa, txg, + &dr->dr_bp_copy, NULL, db->db.db_size, db->db.db_size, &zp, + dbuf_write_nofill_ready, NULL, NULL, + dbuf_write_nofill_done, db, + ZIO_PRIORITY_ASYNC_WRITE, + ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb); + } else { + ASSERT(arc_released(data)); + + /* + * For indirect blocks, we want to setup the children + * ready callback so that we can properly handle an indirect + * block that only contains holes. + */ + arc_write_done_func_t *children_ready_cb = NULL; + if (db->db_level != 0) + children_ready_cb = dbuf_write_children_ready; + + dr->dr_zio = arc_write(pio, os->os_spa, txg, + &dr->dr_bp_copy, data, DBUF_IS_L2CACHEABLE(db), + &zp, dbuf_write_ready, + children_ready_cb, dbuf_write_physdone, + dbuf_write_done, db, ZIO_PRIORITY_ASYNC_WRITE, + ZIO_FLAG_MUSTSUCCEED, &zb); + } +} + +EXPORT_SYMBOL(dbuf_find); +EXPORT_SYMBOL(dbuf_is_metadata); +EXPORT_SYMBOL(dbuf_destroy); +EXPORT_SYMBOL(dbuf_loan_arcbuf); +EXPORT_SYMBOL(dbuf_whichblock); +EXPORT_SYMBOL(dbuf_read); +EXPORT_SYMBOL(dbuf_unoverride); +EXPORT_SYMBOL(dbuf_free_range); +EXPORT_SYMBOL(dbuf_new_size); +EXPORT_SYMBOL(dbuf_release_bp); +EXPORT_SYMBOL(dbuf_dirty); +EXPORT_SYMBOL(dmu_buf_set_crypt_params); +EXPORT_SYMBOL(dmu_buf_will_dirty); +EXPORT_SYMBOL(dmu_buf_is_dirty); +EXPORT_SYMBOL(dmu_buf_will_not_fill); +EXPORT_SYMBOL(dmu_buf_will_fill); +EXPORT_SYMBOL(dmu_buf_fill_done); +EXPORT_SYMBOL(dmu_buf_rele); +EXPORT_SYMBOL(dbuf_assign_arcbuf); +EXPORT_SYMBOL(dbuf_prefetch); +EXPORT_SYMBOL(dbuf_hold_impl); +EXPORT_SYMBOL(dbuf_hold); +EXPORT_SYMBOL(dbuf_hold_level); +EXPORT_SYMBOL(dbuf_create_bonus); +EXPORT_SYMBOL(dbuf_spill_set_blksz); +EXPORT_SYMBOL(dbuf_rm_spill); +EXPORT_SYMBOL(dbuf_add_ref); +EXPORT_SYMBOL(dbuf_rele); +EXPORT_SYMBOL(dbuf_rele_and_unlock); +EXPORT_SYMBOL(dbuf_refcount); +EXPORT_SYMBOL(dbuf_sync_list); +EXPORT_SYMBOL(dmu_buf_set_user); +EXPORT_SYMBOL(dmu_buf_set_user_ie); +EXPORT_SYMBOL(dmu_buf_get_user); +EXPORT_SYMBOL(dmu_buf_get_blkptr); + +/* BEGIN CSTYLED */ +ZFS_MODULE_PARAM(zfs_dbuf_cache, dbuf_cache_, max_bytes, ULONG, ZMOD_RW, + "Maximum size in bytes of the dbuf cache."); + +ZFS_MODULE_PARAM(zfs_dbuf_cache, dbuf_cache_, hiwater_pct, UINT, ZMOD_RW, + "Percentage over dbuf_cache_max_bytes when dbufs must be evicted " + "directly."); + +ZFS_MODULE_PARAM(zfs_dbuf_cache, dbuf_cache_, lowater_pct, UINT, ZMOD_RW, + "Percentage below dbuf_cache_max_bytes when the evict thread stops " + "evicting dbufs."); + +ZFS_MODULE_PARAM(zfs_dbuf, dbuf_, metadata_cache_max_bytes, ULONG, ZMOD_RW, + "Maximum size in bytes of the dbuf metadata cache."); + +ZFS_MODULE_PARAM(zfs_dbuf, dbuf_, cache_shift, INT, ZMOD_RW, + "Set the size of the dbuf cache to a log2 fraction of arc size."); + +ZFS_MODULE_PARAM(zfs_dbuf, dbuf_, metadata_cache_shift, INT, ZMOD_RW, + "Set the size of the dbuf metadata cache to a log2 fraction of arc " + "size."); +/* END CSTYLED */ |