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-rw-r--r--uts/common/fs/zfs/dbuf.c2707
1 files changed, 2707 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/dbuf.c b/uts/common/fs/zfs/dbuf.c
new file mode 100644
index 000000000000..9c4e0296db2b
--- /dev/null
+++ b/uts/common/fs/zfs/dbuf.c
@@ -0,0 +1,2707 @@
+/*
+ * 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.
+ */
+
+#include <sys/zfs_context.h>
+#include <sys/dmu.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>
+
+static void dbuf_destroy(dmu_buf_impl_t *db);
+static int 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);
+
+/*
+ * Global data structures and functions for the dbuf cache.
+ */
+static kmem_cache_t *dbuf_cache;
+
+/* 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);
+ cv_init(&db->db_changed, NULL, CV_DEFAULT, NULL);
+ 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);
+ cv_destroy(&db->db_changed);
+ refcount_destroy(&db->db_holds);
+}
+
+/*
+ * dbuf hash table routines
+ */
+static dbuf_hash_table_t dbuf_hash_table;
+
+static uint64_t dbuf_hash_count;
+
+static uint64_t
+dbuf_hash(void *os, uint64_t obj, uint8_t lvl, uint64_t blkid)
+{
+ uintptr_t osv = (uintptr_t)os;
+ uint64_t crc = -1ULL;
+
+ ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (lvl)) & 0xFF];
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (osv >> 6)) & 0xFF];
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 0)) & 0xFF];
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (obj >> 8)) & 0xFF];
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 0)) & 0xFF];
+ crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (blkid >> 8)) & 0xFF];
+
+ crc ^= (osv>>14) ^ (obj>>16) ^ (blkid>>16);
+
+ return (crc);
+}
+
+#define DBUF_HASH(os, obj, level, blkid) dbuf_hash(os, obj, level, blkid);
+
+#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(dnode_t *dn, uint8_t level, uint64_t blkid)
+{
+ dbuf_hash_table_t *h = &dbuf_hash_table;
+ objset_t *os = dn->dn_objset;
+ uint64_t obj = dn->dn_object;
+ uint64_t hv = DBUF_HASH(os, obj, level, blkid);
+ uint64_t idx = hv & h->hash_table_mask;
+ dmu_buf_impl_t *db;
+
+ 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);
+}
+
+/*
+ * 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 = db->db_blkid;
+ uint64_t hv = DBUF_HASH(os, obj, level, blkid);
+ uint64_t idx = hv & h->hash_table_mask;
+ dmu_buf_impl_t *dbf;
+
+ mutex_enter(DBUF_HASH_MUTEX(h, idx));
+ for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
+ 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);
+ }
+ }
+
+ 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_add_64(&dbuf_hash_count, 1);
+
+ return (NULL);
+}
+
+/*
+ * Remove an entry from the hash table. This operation will
+ * fail if there are any existing holds on the db.
+ */
+static void
+dbuf_hash_remove(dmu_buf_impl_t *db)
+{
+ dbuf_hash_table_t *h = &dbuf_hash_table;
+ uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
+ db->db_level, db->db_blkid);
+ uint64_t idx = hv & h->hash_table_mask;
+ dmu_buf_impl_t *dbf, **dbp;
+
+ /*
+ * We musn't hold db_mtx to maintin lock ordering:
+ * DBUF_HASH_MUTEX > db_mtx.
+ */
+ ASSERT(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;
+ mutex_exit(DBUF_HASH_MUTEX(h, idx));
+ atomic_add_64(&dbuf_hash_count, -1);
+}
+
+static arc_evict_func_t dbuf_do_evict;
+
+static void
+dbuf_evict_user(dmu_buf_impl_t *db)
+{
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+
+ if (db->db_level != 0 || db->db_evict_func == NULL)
+ return;
+
+ if (db->db_user_data_ptr_ptr)
+ *db->db_user_data_ptr_ptr = db->db.db_data;
+ db->db_evict_func(&db->db, db->db_user_ptr);
+ db->db_user_ptr = NULL;
+ db->db_user_data_ptr_ptr = NULL;
+ db->db_evict_func = NULL;
+}
+
+boolean_t
+dbuf_is_metadata(dmu_buf_impl_t *db)
+{
+ if (db->db_level > 0) {
+ return (B_TRUE);
+ } else {
+ boolean_t is_metadata;
+
+ DB_DNODE_ENTER(db);
+ is_metadata = dmu_ot[DB_DNODE(db)->dn_type].ot_metadata;
+ DB_DNODE_EXIT(db);
+
+ return (is_metadata);
+ }
+}
+
+void
+dbuf_evict(dmu_buf_impl_t *db)
+{
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ ASSERT(db->db_buf == NULL);
+ ASSERT(db->db_data_pending == NULL);
+
+ dbuf_clear(db);
+ dbuf_destroy(db);
+}
+
+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 4K block size. The table will take up
+ * totalmem*sizeof(void*)/4K (i.e. 2MB/GB with 8-byte pointers).
+ */
+ while (hsize * 4096 < physmem * PAGESIZE)
+ hsize <<= 1;
+
+retry:
+ h->hash_table_mask = hsize - 1;
+ h->hash_table = kmem_zalloc(hsize * sizeof (void *), KM_NOSLEEP);
+ if (h->hash_table == NULL) {
+ /* XXX - we should really return an error instead of assert */
+ ASSERT(hsize > (1ULL << 10));
+ hsize >>= 1;
+ goto retry;
+ }
+
+ dbuf_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);
+}
+
+void
+dbuf_fini(void)
+{
+ dbuf_hash_table_t *h = &dbuf_hash_table;
+ int i;
+
+ for (i = 0; i < DBUF_MUTEXES; i++)
+ mutex_destroy(&h->hash_mutexes[i]);
+ kmem_free(h->hash_table, (h->hash_table_mask + 1) * sizeof (void *));
+ kmem_cache_destroy(dbuf_cache);
+}
+
+/*
+ * Other stuff.
+ */
+
+#ifdef ZFS_DEBUG
+static void
+dbuf_verify(dmu_buf_impl_t *db)
+{
+ dnode_t *dn;
+ dbuf_dirty_record_t *dr;
+
+ 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 ||
+ !list_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);
+ ASSERT3U(db->db.db_size, >=, dn->dn_bonuslen);
+ ASSERT3U(db->db.db_offset, ==, 0);
+ } else {
+ ASSERT3U(db->db.db_offset, ==, db->db_blkid * db->db.db_size);
+ }
+
+ for (dr = db->db_data_pending; dr != NULL; dr = dr->dr_next)
+ ASSERT(dr->dr_dbuf == db);
+
+ for (dr = db->db_last_dirty; dr != NULL; dr = dr->dr_next)
+ ASSERT(dr->dr_dbuf == db);
+
+ /*
+ * 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 = 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 struct_rwlock. XXX indblksz no longer
+ * grows. safe to do this now?
+ */
+ if (RW_WRITE_HELD(&dn->dn_struct_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.
+ */
+ if (db->db_dirtycnt == 0) {
+ uint64_t *buf = db->db.db_data;
+ int i;
+
+ for (i = 0; i < db->db.db_size >> 3; i++) {
+ ASSERT(buf[i] == 0);
+ }
+ }
+ }
+ DB_DNODE_EXIT(db);
+}
+#endif
+
+static void
+dbuf_update_data(dmu_buf_impl_t *db)
+{
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ if (db->db_level == 0 && db->db_user_data_ptr_ptr) {
+ ASSERT(!refcount_is_zero(&db->db_holds));
+ *db->db_user_data_ptr_ptr = db->db.db_data;
+ }
+}
+
+static void
+dbuf_set_data(dmu_buf_impl_t *db, arc_buf_t *buf)
+{
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ ASSERT(db->db_buf == NULL || !arc_has_callback(db->db_buf));
+ db->db_buf = buf;
+ if (buf != NULL) {
+ ASSERT(buf->b_data != NULL);
+ db->db.db_data = buf->b_data;
+ if (!arc_released(buf))
+ arc_set_callback(buf, dbuf_do_evict, db);
+ dbuf_update_data(db);
+ } else {
+ dbuf_evict_user(db);
+ db->db.db_data = NULL;
+ if (db->db_state != DB_NOFILL)
+ db->db_state = DB_UNCACHED;
+ }
+}
+
+/*
+ * 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;
+
+ mutex_enter(&db->db_mtx);
+ if (arc_released(db->db_buf) || refcount_count(&db->db_holds) > 1) {
+ int blksz = db->db.db_size;
+ spa_t *spa;
+
+ mutex_exit(&db->db_mtx);
+ DB_GET_SPA(&spa, db);
+ abuf = arc_loan_buf(spa, blksz);
+ bcopy(db->db.db_data, abuf->b_data, blksz);
+ } else {
+ abuf = db->db_buf;
+ arc_loan_inuse_buf(abuf, db);
+ dbuf_set_data(db, NULL);
+ mutex_exit(&db->db_mtx);
+ }
+ return (abuf);
+}
+
+uint64_t
+dbuf_whichblock(dnode_t *dn, uint64_t offset)
+{
+ if (dn->dn_datablkshift) {
+ return (offset >> dn->dn_datablkshift);
+ } else {
+ ASSERT3U(offset, <, dn->dn_datablksz);
+ return (0);
+ }
+}
+
+static void
+dbuf_read_done(zio_t *zio, 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(refcount_count(&db->db_holds) > 0);
+ ASSERT(db->db_buf == NULL);
+ ASSERT(db->db.db_data == NULL);
+ if (db->db_level == 0 && db->db_freed_in_flight) {
+ /* we were freed in flight; disregard any error */
+ 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;
+ } else if (zio == NULL || zio->io_error == 0) {
+ dbuf_set_data(db, buf);
+ db->db_state = DB_CACHED;
+ } else {
+ ASSERT(db->db_blkid != DMU_BONUS_BLKID);
+ ASSERT3P(db->db_buf, ==, NULL);
+ VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ db->db_state = DB_UNCACHED;
+ }
+ cv_broadcast(&db->db_changed);
+ dbuf_rele_and_unlock(db, NULL);
+}
+
+static void
+dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
+{
+ dnode_t *dn;
+ spa_t *spa;
+ zbookmark_t zb;
+ uint32_t aflags = ARC_NOWAIT;
+ arc_buf_t *pbuf;
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+ ASSERT(!refcount_is_zero(&db->db_holds));
+ /* We need the struct_rwlock to prevent db_blkptr from changing. */
+ ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ ASSERT(db->db_state == DB_UNCACHED);
+ ASSERT(db->db_buf == NULL);
+
+ if (db->db_blkid == DMU_BONUS_BLKID) {
+ int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
+
+ ASSERT3U(bonuslen, <=, db->db.db_size);
+ db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
+ arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
+ if (bonuslen < DN_MAX_BONUSLEN)
+ bzero(db->db.db_data, DN_MAX_BONUSLEN);
+ if (bonuslen)
+ bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
+ DB_DNODE_EXIT(db);
+ dbuf_update_data(db);
+ db->db_state = DB_CACHED;
+ mutex_exit(&db->db_mtx);
+ return;
+ }
+
+ /*
+ * 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 (db->db_blkptr == NULL || BP_IS_HOLE(db->db_blkptr) ||
+ (db->db_level == 0 && (dnode_block_freed(dn, db->db_blkid) ||
+ BP_IS_HOLE(db->db_blkptr)))) {
+ arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+
+ dbuf_set_data(db, arc_buf_alloc(dn->dn_objset->os_spa,
+ db->db.db_size, db, type));
+ DB_DNODE_EXIT(db);
+ bzero(db->db.db_data, db->db.db_size);
+ db->db_state = DB_CACHED;
+ *flags |= DB_RF_CACHED;
+ mutex_exit(&db->db_mtx);
+ return;
+ }
+
+ spa = dn->dn_objset->os_spa;
+ DB_DNODE_EXIT(db);
+
+ db->db_state = DB_READ;
+ mutex_exit(&db->db_mtx);
+
+ if (DBUF_IS_L2CACHEABLE(db))
+ aflags |= ARC_L2CACHE;
+
+ SET_BOOKMARK(&zb, db->db_objset->os_dsl_dataset ?
+ db->db_objset->os_dsl_dataset->ds_object : DMU_META_OBJSET,
+ db->db.db_object, db->db_level, db->db_blkid);
+
+ dbuf_add_ref(db, NULL);
+ /* ZIO_FLAG_CANFAIL callers have to check the parent zio's error */
+
+ if (db->db_parent)
+ pbuf = db->db_parent->db_buf;
+ else
+ pbuf = db->db_objset->os_phys_buf;
+
+ (void) dsl_read(zio, spa, db->db_blkptr, pbuf,
+ dbuf_read_done, db, ZIO_PRIORITY_SYNC_READ,
+ (*flags & DB_RF_CANFAIL) ? ZIO_FLAG_CANFAIL : ZIO_FLAG_MUSTSUCCEED,
+ &aflags, &zb);
+ if (aflags & ARC_CACHED)
+ *flags |= DB_RF_CACHED;
+}
+
+int
+dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags)
+{
+ int err = 0;
+ int havepzio = (zio != NULL);
+ int 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(!refcount_is_zero(&db->db_holds));
+
+ if (db->db_state == DB_NOFILL)
+ return (EIO);
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+ if ((flags & DB_RF_HAVESTRUCT) == 0)
+ rw_enter(&dn->dn_struct_rwlock, RW_READER);
+
+ 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) {
+ mutex_exit(&db->db_mtx);
+ if (prefetch)
+ dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
+ db->db.db_size, TRUE);
+ if ((flags & DB_RF_HAVESTRUCT) == 0)
+ rw_exit(&dn->dn_struct_rwlock);
+ DB_DNODE_EXIT(db);
+ } else if (db->db_state == DB_UNCACHED) {
+ spa_t *spa = dn->dn_objset->os_spa;
+
+ if (zio == NULL)
+ zio = zio_root(spa, NULL, NULL, ZIO_FLAG_CANFAIL);
+ dbuf_read_impl(db, zio, &flags);
+
+ /* dbuf_read_impl has dropped db_mtx for us */
+
+ if (prefetch)
+ dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
+ db->db.db_size, flags & DB_RF_CACHED);
+
+ if ((flags & DB_RF_HAVESTRUCT) == 0)
+ rw_exit(&dn->dn_struct_rwlock);
+ DB_DNODE_EXIT(db);
+
+ if (!havepzio)
+ err = zio_wait(zio);
+ } else {
+ mutex_exit(&db->db_mtx);
+ if (prefetch)
+ dmu_zfetch(&dn->dn_zfetch, db->db.db_offset,
+ db->db.db_size, TRUE);
+ if ((flags & DB_RF_HAVESTRUCT) == 0)
+ rw_exit(&dn->dn_struct_rwlock);
+ DB_DNODE_EXIT(db);
+
+ mutex_enter(&db->db_mtx);
+ if ((flags & DB_RF_NEVERWAIT) == 0) {
+ while (db->db_state == DB_READ ||
+ db->db_state == DB_FILL) {
+ ASSERT(db->db_state == DB_READ ||
+ (flags & DB_RF_HAVESTRUCT) == 0);
+ cv_wait(&db->db_changed, &db->db_mtx);
+ }
+ if (db->db_state == DB_UNCACHED)
+ err = EIO;
+ }
+ mutex_exit(&db->db_mtx);
+ }
+
+ ASSERT(err || havepzio || db->db_state == DB_CACHED);
+ return (err);
+}
+
+static void
+dbuf_noread(dmu_buf_impl_t *db)
+{
+ ASSERT(!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) {
+ arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+ spa_t *spa;
+
+ ASSERT(db->db_buf == NULL);
+ ASSERT(db->db.db_data == NULL);
+ DB_GET_SPA(&spa, db);
+ dbuf_set_data(db, arc_buf_alloc(spa, db->db.db_size, db, type));
+ db->db_state = DB_FILL;
+ } else if (db->db_state == DB_NOFILL) {
+ dbuf_set_data(db, NULL);
+ } else {
+ ASSERT3U(db->db_state, ==, DB_CACHED);
+ }
+ mutex_exit(&db->db_mtx);
+}
+
+/*
+ * 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 modify them in the current active group.
+ *
+ * This function is used in two places: when we are dirtying a
+ * buffer for the first time in a txg, and when we are freeing
+ * a range in a dnode that includes this buffer.
+ *
+ * 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 = db->db_last_dirty;
+
+ 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.
+ */
+ ASSERT(dr->dr_txg >= txg - 2);
+ if (db->db_blkid == DMU_BONUS_BLKID) {
+ /* Note that the data bufs here are zio_bufs */
+ dr->dt.dl.dr_data = zio_buf_alloc(DN_MAX_BONUSLEN);
+ arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
+ bcopy(db->db.db_data, dr->dt.dl.dr_data, DN_MAX_BONUSLEN);
+ } else if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
+ int size = db->db.db_size;
+ arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+ spa_t *spa;
+
+ DB_GET_SPA(&spa, db);
+ dr->dt.dl.dr_data = arc_buf_alloc(spa, size, db, type);
+ bcopy(db->db.db_data, dr->dt.dl.dr_data->b_data, size);
+ } else {
+ dbuf_set_data(db, NULL);
+ }
+}
+
+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));
+ 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)) {
+ spa_t *spa;
+
+ DB_GET_SPA(&spa, db);
+ zio_free(spa, txg, bp);
+ }
+ dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
+ /*
+ * 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. Also, if we happen accross any level-1 dbufs in the
+ * range that have not already been marked dirty, mark them dirty so
+ * they stay in memory.
+ */
+void
+dbuf_free_range(dnode_t *dn, uint64_t start, uint64_t end, dmu_tx_t *tx)
+{
+ dmu_buf_impl_t *db, *db_next;
+ uint64_t txg = tx->tx_txg;
+ int epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
+ uint64_t first_l1 = start >> epbs;
+ uint64_t last_l1 = end >> epbs;
+
+ if (end > dn->dn_maxblkid && (end != DMU_SPILL_BLKID)) {
+ end = dn->dn_maxblkid;
+ last_l1 = end >> epbs;
+ }
+ dprintf_dnode(dn, "start=%llu end=%llu\n", start, end);
+ mutex_enter(&dn->dn_dbufs_mtx);
+ for (db = list_head(&dn->dn_dbufs); db; db = db_next) {
+ db_next = list_next(&dn->dn_dbufs, db);
+ ASSERT(db->db_blkid != DMU_BONUS_BLKID);
+
+ if (db->db_level == 1 &&
+ db->db_blkid >= first_l1 && db->db_blkid <= last_l1) {
+ mutex_enter(&db->db_mtx);
+ if (db->db_last_dirty &&
+ db->db_last_dirty->dr_txg < txg) {
+ dbuf_add_ref(db, FTAG);
+ mutex_exit(&db->db_mtx);
+ dbuf_will_dirty(db, tx);
+ dbuf_rele(db, FTAG);
+ } else {
+ mutex_exit(&db->db_mtx);
+ }
+ }
+
+ if (db->db_level != 0)
+ continue;
+ dprintf_dbuf(db, "found buf %s\n", "");
+ if (db->db_blkid < start || db->db_blkid > end)
+ continue;
+
+ /* found a level 0 buffer in the range */
+ if (dbuf_undirty(db, tx))
+ continue;
+
+ mutex_enter(&db->db_mtx);
+ 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 (refcount_count(&db->db_holds) == 0) {
+ ASSERT(db->db_buf);
+ dbuf_clear(db);
+ continue;
+ }
+ /* The dbuf is referenced */
+
+ if (db->db_last_dirty != NULL) {
+ dbuf_dirty_record_t *dr = db->db_last_dirty;
+
+ 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);
+ bzero(db->db.db_data, db->db.db_size);
+ arc_buf_freeze(db->db_buf);
+ }
+
+ mutex_exit(&db->db_mtx);
+ }
+ mutex_exit(&dn->dn_dbufs_mtx);
+}
+
+static int
+dbuf_block_freeable(dmu_buf_impl_t *db)
+{
+ dsl_dataset_t *ds = db->db_objset->os_dsl_dataset;
+ uint64_t birth_txg = 0;
+
+ /*
+ * We don't need any locking to protect db_blkptr:
+ * If it's syncing, then db_last_dirty will be set
+ * so we'll ignore db_blkptr.
+ */
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ if (db->db_last_dirty)
+ birth_txg = db->db_last_dirty->dr_txg;
+ else if (db->db_blkptr)
+ birth_txg = db->db_blkptr->blk_birth;
+
+ /*
+ * If we don't exist or are in a snapshot, we can't be freed.
+ * Don't pass the bp to dsl_dataset_block_freeable() since we
+ * are holding the db_mtx lock and might deadlock if we are
+ * prefetching a dedup-ed block.
+ */
+ if (birth_txg)
+ return (ds == NULL ||
+ dsl_dataset_block_freeable(ds, NULL, birth_txg));
+ else
+ return (FALSE);
+}
+
+void
+dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx)
+{
+ arc_buf_t *buf, *obuf;
+ 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 does *this* func really need the lock? */
+ ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
+
+ /*
+ * This call to dbuf_will_dirty() with the dn_struct_rwlock held
+ * is OK, because there can be no other references to the db
+ * when we are changing its size, so no concurrent DB_FILL can
+ * be happening.
+ */
+ /*
+ * XXX we should be doing a dbuf_read, checking the return
+ * value and returning that up to our callers
+ */
+ dbuf_will_dirty(db, tx);
+
+ /* create the data buffer for the new block */
+ buf = arc_buf_alloc(dn->dn_objset->os_spa, size, db, type);
+
+ /* copy old block data to the new block */
+ obuf = db->db_buf;
+ bcopy(obuf->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);
+ VERIFY(arc_buf_remove_ref(obuf, db) == 1);
+ db->db.db_size = size;
+
+ if (db->db_level == 0) {
+ ASSERT3U(db->db_last_dirty->dr_txg, ==, tx->tx_txg);
+ db->db_last_dirty->dt.dl.dr_data = buf;
+ }
+ mutex_exit(&db->db_mtx);
+
+ dnode_willuse_space(dn, size-osize, tx);
+ DB_DNODE_EXIT(db);
+}
+
+void
+dbuf_release_bp(dmu_buf_impl_t *db)
+{
+ objset_t *os;
+ zbookmark_t zb;
+
+ DB_GET_OBJSET(&os, db);
+ 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));
+
+ zb.zb_objset = os->os_dsl_dataset ?
+ os->os_dsl_dataset->ds_object : 0;
+ zb.zb_object = db->db.db_object;
+ zb.zb_level = db->db_level;
+ zb.zb_blkid = db->db_blkid;
+ (void) arc_release_bp(db->db_buf, db,
+ db->db_blkptr, os->os_spa, &zb);
+}
+
+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 **drp, *dr;
+ int drop_struct_lock = FALSE;
+ boolean_t do_free_accounting = B_FALSE;
+ int txgoff = tx->tx_txg & TXG_MASK;
+
+ ASSERT(tx->tx_txg != 0);
+ ASSERT(!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.
+ */
+ 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);
+ /*
+ * 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);
+ /*
+ * Don't set dirtyctx to SYNC if we're just modifying this as we
+ * initialize the objset.
+ */
+ if (dn->dn_dirtyctx == DN_UNDIRTIED &&
+ !BP_IS_HOLE(dn->dn_objset->os_rootbp)) {
+ dn->dn_dirtyctx =
+ (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN);
+ ASSERT(dn->dn_dirtyctx_firstset == NULL);
+ dn->dn_dirtyctx_firstset = kmem_alloc(1, KM_SLEEP);
+ }
+ 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.
+ */
+ drp = &db->db_last_dirty;
+ ASSERT(*drp == NULL || (*drp)->dr_txg <= tx->tx_txg ||
+ db->db.db_object == DMU_META_DNODE_OBJECT);
+ while ((dr = *drp) != NULL && dr->dr_txg > tx->tx_txg)
+ drp = &dr->dr_next;
+ if (dr && dr->dr_txg == tx->tx_txg) {
+ DB_DNODE_EXIT(db);
+
+ 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)
+ arc_buf_thaw(db->db_buf);
+ }
+ mutex_exit(&db->db_mtx);
+ return (dr);
+ }
+
+ /*
+ * 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);
+ 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);
+
+ /*
+ * 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;
+ ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
+ os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
+ 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) {
+ /*
+ * Update the accounting.
+ * Note: we delay "free accounting" until after we drop
+ * the db_mtx. This keeps us from grabbing other locks
+ * (and possibly deadlocking) in bp_get_dsize() while
+ * also holding the db_mtx.
+ */
+ dnode_willuse_space(dn, db->db.db_size, tx);
+ do_free_accounting = dbuf_block_freeable(db);
+ }
+
+ /*
+ * 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);
+ 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_DEFAULT, NULL);
+ list_create(&dr->dt.di.dr_children,
+ sizeof (dbuf_dirty_record_t),
+ offsetof(dbuf_dirty_record_t, dr_dirty_node));
+ }
+ dr->dr_dbuf = db;
+ dr->dr_txg = tx->tx_txg;
+ dr->dr_next = *drp;
+ *drp = 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);
+ dnode_clear_range(dn, db->db_blkid, 1, tx);
+ 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);
+ } else if (do_free_accounting) {
+ blkptr_t *bp = db->db_blkptr;
+ int64_t willfree = (bp && !BP_IS_HOLE(bp)) ?
+ bp_get_dsize(os->os_spa, bp) : db->db.db_size;
+ /*
+ * This is only a guess -- if the dbuf is dirty
+ * in a previous txg, we don't know how much
+ * space it will use on disk yet. We should
+ * really have the struct_rwlock to access
+ * db_blkptr, but since this is just a guess,
+ * it's OK if we get an odd answer.
+ */
+ ddt_prefetch(os->os_spa, bp);
+ dnode_willuse_space(dn, -willfree, tx);
+ }
+
+ if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
+ rw_enter(&dn->dn_struct_rwlock, RW_READER);
+ drop_struct_lock = TRUE;
+ }
+
+ if (db->db_level == 0) {
+ dnode_new_blkid(dn, db->db_blkid, tx, drop_struct_lock);
+ 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_lock)
+ 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);
+ /* possible race with dbuf_undirty() */
+ if (db->db_last_dirty == 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_lock)
+ rw_exit(&dn->dn_struct_rwlock);
+ }
+
+ dnode_setdirty(dn, tx);
+ DB_DNODE_EXIT(db);
+ return (dr);
+}
+
+static int
+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, **drp;
+
+ ASSERT(txg != 0);
+ ASSERT(db->db_blkid != DMU_BONUS_BLKID);
+
+ mutex_enter(&db->db_mtx);
+ /*
+ * If this buffer is not dirty, we're done.
+ */
+ for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
+ if (dr->dr_txg <= txg)
+ break;
+ if (dr == NULL || dr->dr_txg < txg) {
+ mutex_exit(&db->db_mtx);
+ return (0);
+ }
+ ASSERT(dr->dr_txg == txg);
+ ASSERT(dr->dr_dbuf == db);
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+
+ /*
+ * If this buffer is currently held, we cannot undirty
+ * it, since one of the current holders may be in the
+ * middle of an update. Note that users of dbuf_undirty()
+ * should not place a hold on the dbuf before the call.
+ */
+ if (refcount_count(&db->db_holds) > db->db_dirtycnt) {
+ mutex_exit(&db->db_mtx);
+ /* Make sure we don't toss this buffer at sync phase */
+ mutex_enter(&dn->dn_mtx);
+ dnode_clear_range(dn, db->db_blkid, 1, tx);
+ mutex_exit(&dn->dn_mtx);
+ DB_DNODE_EXIT(db);
+ return (0);
+ }
+
+ dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
+
+ ASSERT(db->db.db_size != 0);
+
+ /* XXX would be nice to fix up dn_towrite_space[] */
+
+ *drp = dr->dr_next;
+
+ 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_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_level == 0) {
+ 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)
+ VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
+ db) == 1);
+ }
+ } else {
+ ASSERT(db->db_buf != NULL);
+ ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
+ mutex_destroy(&dr->dt.di.dr_mtx);
+ list_destroy(&dr->dt.di.dr_children);
+ }
+ kmem_free(dr, sizeof (dbuf_dirty_record_t));
+
+ ASSERT(db->db_dirtycnt > 0);
+ db->db_dirtycnt -= 1;
+
+ if (refcount_remove(&db->db_holds, (void *)(uintptr_t)txg) == 0) {
+ arc_buf_t *buf = db->db_buf;
+
+ ASSERT(db->db_state == DB_NOFILL || arc_released(buf));
+ dbuf_set_data(db, NULL);
+ VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ dbuf_evict(db);
+ return (1);
+ }
+
+ mutex_exit(&db->db_mtx);
+ return (0);
+}
+
+#pragma weak dmu_buf_will_dirty = dbuf_will_dirty
+void
+dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
+{
+ int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
+
+ ASSERT(tx->tx_txg != 0);
+ ASSERT(!refcount_is_zero(&db->db_holds));
+
+ DB_DNODE_ENTER(db);
+ if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
+ rf |= DB_RF_HAVESTRUCT;
+ DB_DNODE_EXIT(db);
+ (void) dbuf_read(db, NULL, rf);
+ (void) dbuf_dirty(db, tx);
+}
+
+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;
+
+ 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(!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);
+}
+
+#pragma weak dmu_buf_fill_done = dbuf_fill_done
+/* ARGSUSED */
+void
+dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
+{
+ mutex_enter(&db->db_mtx);
+ DBUF_VERIFY(db);
+
+ if (db->db_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;
+ }
+ db->db_state = DB_CACHED;
+ cv_broadcast(&db->db_changed);
+ }
+ mutex_exit(&db->db_mtx);
+}
+
+/*
+ * 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(!refcount_is_zero(&db->db_holds));
+ ASSERT(db->db_blkid != DMU_BONUS_BLKID);
+ ASSERT(db->db_level == 0);
+ ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
+ ASSERT(buf != NULL);
+ ASSERT(arc_buf_size(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 &&
+ refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
+ mutex_exit(&db->db_mtx);
+ (void) dbuf_dirty(db, tx);
+ bcopy(buf->b_data, db->db.db_data, db->db.db_size);
+ VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ xuio_stat_wbuf_copied();
+ return;
+ }
+
+ xuio_stat_wbuf_nocopy();
+ if (db->db_state == DB_CACHED) {
+ dbuf_dirty_record_t *dr = db->db_last_dirty;
+
+ 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;
+ VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+ } else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
+ arc_release(db->db_buf, db);
+ VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+ }
+ db->db_buf = NULL;
+ }
+ ASSERT(db->db_buf == NULL);
+ dbuf_set_data(db, buf);
+ db->db_state = DB_FILL;
+ mutex_exit(&db->db_mtx);
+ (void) dbuf_dirty(db, tx);
+ dbuf_fill_done(db, tx);
+}
+
+/*
+ * "Clear" the contents of this dbuf. This will mark the dbuf
+ * EVICTING and clear *most* of its references. Unfortunetely,
+ * when we are not holding the dn_dbufs_mtx, we can't clear the
+ * entry in the dn_dbufs list. We have to wait until dbuf_destroy()
+ * in this case. For callers from the DMU we will usually see:
+ * dbuf_clear()->arc_buf_evict()->dbuf_do_evict()->dbuf_destroy()
+ * For the arc callback, we will usually see:
+ * dbuf_do_evict()->dbuf_clear();dbuf_destroy()
+ * Sometimes, though, we will get a mix of these two:
+ * DMU: dbuf_clear()->arc_buf_evict()
+ * ARC: dbuf_do_evict()->dbuf_destroy()
+ */
+void
+dbuf_clear(dmu_buf_impl_t *db)
+{
+ dnode_t *dn;
+ dmu_buf_impl_t *parent = db->db_parent;
+ dmu_buf_impl_t *dndb;
+ int dbuf_gone = FALSE;
+
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+ ASSERT(refcount_is_zero(&db->db_holds));
+
+ dbuf_evict_user(db);
+
+ if (db->db_state == DB_CACHED) {
+ ASSERT(db->db.db_data != NULL);
+ if (db->db_blkid == DMU_BONUS_BLKID) {
+ zio_buf_free(db->db.db_data, DN_MAX_BONUSLEN);
+ arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
+ }
+ db->db.db_data = NULL;
+ db->db_state = DB_UNCACHED;
+ }
+
+ ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
+ ASSERT(db->db_data_pending == NULL);
+
+ db->db_state = DB_EVICTING;
+ db->db_blkptr = NULL;
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+ dndb = dn->dn_dbuf;
+ if (db->db_blkid != DMU_BONUS_BLKID && MUTEX_HELD(&dn->dn_dbufs_mtx)) {
+ list_remove(&dn->dn_dbufs, db);
+ (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
+ membar_producer();
+ DB_DNODE_EXIT(db);
+ /*
+ * 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.
+ */
+ dnode_rele(dn, db);
+ db->db_dnode_handle = NULL;
+ } else {
+ DB_DNODE_EXIT(db);
+ }
+
+ if (db->db_buf)
+ dbuf_gone = arc_buf_evict(db->db_buf);
+
+ if (!dbuf_gone)
+ mutex_exit(&db->db_mtx);
+
+ /*
+ * If this dbuf is referenced from an indirect dbuf,
+ * decrement the ref count on the indirect dbuf.
+ */
+ if (parent && parent != dndb)
+ dbuf_rele(parent, db);
+}
+
+static int
+dbuf_findbp(dnode_t *dn, int level, uint64_t blkid, int fail_sparse,
+ dmu_buf_impl_t **parentp, blkptr_t **bpp)
+{
+ int nlevels, epbs;
+
+ *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->dn_phys->dn_spill;
+ else
+ *bpp = NULL;
+ dbuf_add_ref(dn->dn_dbuf, NULL);
+ *parentp = dn->dn_dbuf;
+ mutex_exit(&dn->dn_mtx);
+ return (0);
+ }
+
+ if (dn->dn_phys->dn_nlevels == 0)
+ nlevels = 1;
+ else
+ nlevels = dn->dn_phys->dn_nlevels;
+
+ epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
+
+ ASSERT3U(level * epbs, <, 64);
+ ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
+ if (level >= nlevels ||
+ (blkid > (dn->dn_phys->dn_maxblkid >> (level * epbs)))) {
+ /* the buffer has no parent yet */
+ return (ENOENT);
+ } else if (level < nlevels-1) {
+ /* this block is referenced from an indirect block */
+ int err = dbuf_hold_impl(dn, level+1,
+ blkid >> epbs, fail_sparse, 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);
+ }
+ *bpp = ((blkptr_t *)(*parentp)->db.db_data) +
+ (blkid & ((1ULL << epbs) - 1));
+ 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_cache, KM_SLEEP);
+
+ db->db_objset = os;
+ db->db.db_object = dn->dn_object;
+ db->db_level = level;
+ db->db_blkid = blkid;
+ db->db_last_dirty = NULL;
+ db->db_dirtycnt = 0;
+ db->db_dnode_handle = dn->dn_handle;
+ db->db_parent = parent;
+ db->db_blkptr = blkptr;
+
+ db->db_user_ptr = NULL;
+ db->db_user_data_ptr_ptr = NULL;
+ db->db_evict_func = NULL;
+ db->db_immediate_evict = 0;
+ db->db_freed_in_flight = 0;
+
+ if (blkid == DMU_BONUS_BLKID) {
+ ASSERT3P(parent, ==, dn->dn_dbuf);
+ db->db.db_size = DN_MAX_BONUSLEN -
+ (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;
+ /* the bonus dbuf is not placed in the hash table */
+ arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
+ 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 its added to the
+ * dn_dbufs list.
+ */
+ mutex_enter(&dn->dn_dbufs_mtx);
+ db->db_state = DB_EVICTING;
+ if ((odb = dbuf_hash_insert(db)) != NULL) {
+ /* someone else inserted it first */
+ kmem_cache_free(dbuf_cache, db);
+ mutex_exit(&dn->dn_dbufs_mtx);
+ return (odb);
+ }
+ list_insert_head(&dn->dn_dbufs, db);
+ db->db_state = DB_UNCACHED;
+ mutex_exit(&dn->dn_dbufs_mtx);
+ arc_space_consume(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
+
+ if (parent && parent != dn->dn_dbuf)
+ dbuf_add_ref(parent, db);
+
+ ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT ||
+ refcount_count(&dn->dn_holds) > 0);
+ (void) refcount_add(&dn->dn_holds, db);
+ (void) atomic_inc_32_nv(&dn->dn_dbufs_count);
+
+ dprintf_dbuf(db, "db=%p\n", db);
+
+ return (db);
+}
+
+static int
+dbuf_do_evict(void *private)
+{
+ arc_buf_t *buf = private;
+ dmu_buf_impl_t *db = buf->b_private;
+
+ if (!MUTEX_HELD(&db->db_mtx))
+ mutex_enter(&db->db_mtx);
+
+ ASSERT(refcount_is_zero(&db->db_holds));
+
+ if (db->db_state != DB_EVICTING) {
+ ASSERT(db->db_state == DB_CACHED);
+ DBUF_VERIFY(db);
+ db->db_buf = NULL;
+ dbuf_evict(db);
+ } else {
+ mutex_exit(&db->db_mtx);
+ dbuf_destroy(db);
+ }
+ return (0);
+}
+
+static void
+dbuf_destroy(dmu_buf_impl_t *db)
+{
+ ASSERT(refcount_is_zero(&db->db_holds));
+
+ if (db->db_blkid != DMU_BONUS_BLKID) {
+ /*
+ * If this dbuf is still on the dn_dbufs list,
+ * remove it from that list.
+ */
+ if (db->db_dnode_handle != NULL) {
+ dnode_t *dn;
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+ mutex_enter(&dn->dn_dbufs_mtx);
+ list_remove(&dn->dn_dbufs, db);
+ (void) atomic_dec_32_nv(&dn->dn_dbufs_count);
+ mutex_exit(&dn->dn_dbufs_mtx);
+ DB_DNODE_EXIT(db);
+ /*
+ * 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.
+ */
+ dnode_rele(dn, db);
+ db->db_dnode_handle = NULL;
+ }
+ dbuf_hash_remove(db);
+ }
+ db->db_parent = NULL;
+ db->db_buf = NULL;
+
+ ASSERT(!list_link_active(&db->db_link));
+ ASSERT(db->db.db_data == NULL);
+ ASSERT(db->db_hash_next == NULL);
+ ASSERT(db->db_blkptr == NULL);
+ ASSERT(db->db_data_pending == NULL);
+
+ kmem_cache_free(dbuf_cache, db);
+ arc_space_return(sizeof (dmu_buf_impl_t), ARC_SPACE_OTHER);
+}
+
+void
+dbuf_prefetch(dnode_t *dn, uint64_t blkid)
+{
+ dmu_buf_impl_t *db = NULL;
+ blkptr_t *bp = NULL;
+
+ ASSERT(blkid != DMU_BONUS_BLKID);
+ ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
+
+ if (dnode_block_freed(dn, blkid))
+ return;
+
+ /* dbuf_find() returns with db_mtx held */
+ if (db = dbuf_find(dn, 0, blkid)) {
+ /*
+ * This dbuf is already in the cache. We assume that
+ * it is already CACHED, or else about to be either
+ * read or filled.
+ */
+ mutex_exit(&db->db_mtx);
+ return;
+ }
+
+ if (dbuf_findbp(dn, 0, blkid, TRUE, &db, &bp) == 0) {
+ if (bp && !BP_IS_HOLE(bp)) {
+ int priority = dn->dn_type == DMU_OT_DDT_ZAP ?
+ ZIO_PRIORITY_DDT_PREFETCH : ZIO_PRIORITY_ASYNC_READ;
+ arc_buf_t *pbuf;
+ dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
+ uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
+ zbookmark_t zb;
+
+ SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
+ dn->dn_object, 0, blkid);
+
+ if (db)
+ pbuf = db->db_buf;
+ else
+ pbuf = dn->dn_objset->os_phys_buf;
+
+ (void) dsl_read(NULL, dn->dn_objset->os_spa,
+ bp, pbuf, NULL, NULL, priority,
+ ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE,
+ &aflags, &zb);
+ }
+ if (db)
+ dbuf_rele(db, NULL);
+ }
+}
+
+/*
+ * 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, int fail_sparse,
+ void *tag, dmu_buf_impl_t **dbp)
+{
+ dmu_buf_impl_t *db, *parent = NULL;
+
+ ASSERT(blkid != DMU_BONUS_BLKID);
+ ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock));
+ ASSERT3U(dn->dn_nlevels, >, level);
+
+ *dbp = NULL;
+top:
+ /* dbuf_find() returns with db_mtx held */
+ db = dbuf_find(dn, level, blkid);
+
+ if (db == NULL) {
+ blkptr_t *bp = NULL;
+ int err;
+
+ 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 = 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 (db->db_buf && refcount_is_zero(&db->db_holds)) {
+ arc_buf_add_ref(db->db_buf, db);
+ if (db->db_buf->b_data == NULL) {
+ dbuf_clear(db);
+ if (parent) {
+ dbuf_rele(parent, NULL);
+ parent = NULL;
+ }
+ goto top;
+ }
+ 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 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) {
+ arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+
+ dbuf_set_data(db,
+ arc_buf_alloc(dn->dn_objset->os_spa,
+ db->db.db_size, db, type));
+ bcopy(dr->dt.dl.dr_data->b_data, db->db.db_data,
+ db->db.db_size);
+ }
+ }
+
+ (void) refcount_add(&db->db_holds, tag);
+ dbuf_update_data(db);
+ 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)
+{
+ dmu_buf_impl_t *db;
+ int err = dbuf_hold_impl(dn, 0, blkid, FALSE, tag, &db);
+ return (err ? NULL : db);
+}
+
+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, 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;
+ dnode_t *dn;
+
+ if (db->db_blkid != DMU_SPILL_BLKID)
+ return (ENOTSUP);
+ if (blksz == 0)
+ blksz = SPA_MINBLOCKSIZE;
+ if (blksz > SPA_MAXBLOCKSIZE)
+ blksz = SPA_MAXBLOCKSIZE;
+ else
+ blksz = P2ROUNDUP(blksz, SPA_MINBLOCKSIZE);
+
+ DB_DNODE_ENTER(db);
+ dn = DB_DNODE(db);
+ rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
+ dbuf_new_size(db, blksz, tx);
+ rw_exit(&dn->dn_struct_rwlock);
+ DB_DNODE_EXIT(db);
+
+ 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 = refcount_add(&db->db_holds, tag);
+ ASSERT(holds > 1);
+}
+
+/*
+ * 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.
+ */
+#pragma weak dmu_buf_rele = dbuf_rele
+void
+dbuf_rele(dmu_buf_impl_t *db, void *tag)
+{
+ mutex_enter(&db->db_mtx);
+ dbuf_rele_and_unlock(db, tag);
+}
+
+/*
+ * dbuf_rele() for an already-locked dbuf. This is necessary to allow
+ * db_dirtycnt and db_holds to be updated atomically.
+ */
+void
+dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag)
+{
+ int64_t holds;
+
+ 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 = 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 && 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_immediate_evict)
+ dbuf_evict_user(db);
+
+ if (holds == 0) {
+ if (db->db_blkid == DMU_BONUS_BLKID) {
+ mutex_exit(&db->db_mtx);
+
+ /*
+ * If the dnode moves here, we cannot cross this barrier
+ * until the move completes.
+ */
+ DB_DNODE_ENTER(db);
+ (void) atomic_dec_32_nv(&DB_DNODE(db)->dn_dbufs_count);
+ DB_DNODE_EXIT(db);
+ /*
+ * The bonus buffer's dnode hold is no longer discounted
+ * in dnode_move(). The dnode cannot move until after
+ * the dnode_rele().
+ */
+ dnode_rele(DB_DNODE(db), 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_evict(db);
+ } else if (arc_released(db->db_buf)) {
+ arc_buf_t *buf = db->db_buf;
+ /*
+ * This dbuf has anonymous data associated with it.
+ */
+ dbuf_set_data(db, NULL);
+ VERIFY(arc_buf_remove_ref(buf, db) == 1);
+ dbuf_evict(db);
+ } else {
+ VERIFY(arc_buf_remove_ref(db->db_buf, db) == 0);
+ if (!DBUF_IS_CACHEABLE(db))
+ dbuf_clear(db);
+ else
+ mutex_exit(&db->db_mtx);
+ }
+ } else {
+ mutex_exit(&db->db_mtx);
+ }
+}
+
+#pragma weak dmu_buf_refcount = dbuf_refcount
+uint64_t
+dbuf_refcount(dmu_buf_impl_t *db)
+{
+ return (refcount_count(&db->db_holds));
+}
+
+void *
+dmu_buf_set_user(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
+ dmu_buf_evict_func_t *evict_func)
+{
+ return (dmu_buf_update_user(db_fake, NULL, user_ptr,
+ user_data_ptr_ptr, evict_func));
+}
+
+void *
+dmu_buf_set_user_ie(dmu_buf_t *db_fake, void *user_ptr, void *user_data_ptr_ptr,
+ dmu_buf_evict_func_t *evict_func)
+{
+ dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
+
+ db->db_immediate_evict = TRUE;
+ return (dmu_buf_update_user(db_fake, NULL, user_ptr,
+ user_data_ptr_ptr, evict_func));
+}
+
+void *
+dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr, void *user_ptr,
+ void *user_data_ptr_ptr, dmu_buf_evict_func_t *evict_func)
+{
+ dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
+ ASSERT(db->db_level == 0);
+
+ ASSERT((user_ptr == NULL) == (evict_func == NULL));
+
+ mutex_enter(&db->db_mtx);
+
+ if (db->db_user_ptr == old_user_ptr) {
+ db->db_user_ptr = user_ptr;
+ db->db_user_data_ptr_ptr = user_data_ptr_ptr;
+ db->db_evict_func = evict_func;
+
+ dbuf_update_data(db);
+ } else {
+ old_user_ptr = db->db_user_ptr;
+ }
+
+ mutex_exit(&db->db_mtx);
+ return (old_user_ptr);
+}
+
+void *
+dmu_buf_get_user(dmu_buf_t *db_fake)
+{
+ dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
+ ASSERT(!refcount_is_zero(&db->db_holds));
+
+ return (db->db_user_ptr);
+}
+
+boolean_t
+dmu_buf_freeable(dmu_buf_t *dbuf)
+{
+ boolean_t res = B_FALSE;
+ dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
+
+ if (db->db_blkptr)
+ res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
+ db->db_blkptr, db->db_blkptr->blk_birth);
+
+ return (res);
+}
+
+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->dn_phys->dn_spill;
+ 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 mis-match).
+ */
+ 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);
+ (void) dbuf_hold_impl(dn, db->db_level+1,
+ db->db_blkid >> epbs, FALSE, db, &parent);
+ 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_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);
+
+ 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);
+ ASSERT3U(db->db.db_size, ==, 1<<dn->dn_phys->dn_indblkshift);
+ dbuf_check_blkptr(dn, db);
+ DB_DNODE_EXIT(db);
+
+ 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, tx);
+ ASSERT(list_head(&dr->dt.di.dr_children) == NULL);
+ mutex_exit(&dr->dt.di.dr_mtx);
+ zio_nowait(zio);
+}
+
+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);
+ 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) {
+ dbuf_dirty_record_t **drp;
+
+ ASSERT(*datap != NULL);
+ ASSERT3U(db->db_level, ==, 0);
+ ASSERT3U(dn->dn_phys->dn_bonuslen, <=, DN_MAX_BONUSLEN);
+ bcopy(*datap, DN_BONUS(dn->dn_phys), dn->dn_phys->dn_bonuslen);
+ DB_DNODE_EXIT(db);
+
+ if (*datap != db->db.db_data) {
+ zio_buf_free(*datap, DN_MAX_BONUSLEN);
+ arc_space_return(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
+ }
+ db->db_data_pending = NULL;
+ drp = &db->db_last_dirty;
+ while (*drp != dr)
+ drp = &(*drp)->dr_next;
+ ASSERT(dr->dr_next == NULL);
+ ASSERT(dr->dr_dbuf == db);
+ *drp = dr->dr_next;
+ kmem_free(dr, sizeof (dbuf_dirty_record_t));
+ ASSERT(db->db_dirtycnt > 0);
+ db->db_dirtycnt -= 1;
+ dbuf_rele_and_unlock(db, (void *)(uintptr_t)txg);
+ 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 (db->db_state != DB_NOFILL &&
+ dn->dn_object != DMU_META_DNODE_OBJECT &&
+ 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).
+ */
+ int blksz = arc_buf_size(*datap);
+ arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+ *datap = arc_buf_alloc(os->os_spa, blksz, db, type);
+ bcopy(db->db.db_data, (*datap)->b_data, blksz);
+ }
+ 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, 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;
+ }
+ 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;
+
+ ASSERT(db->db_blkptr == 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_IS_HOLE(bp)) {
+ ASSERT(bp->blk_fill == 0);
+ DB_DNODE_EXIT(db);
+ return;
+ }
+
+ 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));
+ 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(db->db_blkptr)) &&
+ db->db_blkptr == &dn->dn_phys->dn_spill);
+ }
+#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)
+ dn->dn_phys->dn_maxblkid = db->db_blkid;
+ mutex_exit(&dn->dn_mtx);
+
+ if (dn->dn_type == DMU_OT_DNODE) {
+ dnode_phys_t *dnp = db->db.db_data;
+ for (i = db->db.db_size >> DNODE_SHIFT; i > 0;
+ i--, dnp++) {
+ if (dnp->dn_type != DMU_OT_NONE)
+ fill++;
+ }
+ } 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 += ibp->blk_fill;
+ }
+ }
+ DB_DNODE_EXIT(db);
+
+ bp->blk_fill = fill;
+
+ mutex_exit(&db->db_mtx);
+}
+
+/* ARGSUSED */
+static void
+dbuf_write_done(zio_t *zio, arc_buf_t *buf, void *vdb)
+{
+ dmu_buf_impl_t *db = vdb;
+ blkptr_t *bp = zio->io_bp;
+ blkptr_t *bp_orig = &zio->io_bp_orig;
+ uint64_t txg = zio->io_txg;
+ dbuf_dirty_record_t **drp, *dr;
+
+ ASSERT3U(zio->io_error, ==, 0);
+ ASSERT(db->db_blkptr == bp);
+
+ if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
+ ASSERT(BP_EQUAL(bp, bp_orig));
+ } else {
+ objset_t *os;
+ dsl_dataset_t *ds;
+ dmu_tx_t *tx;
+
+ DB_GET_OBJSET(&os, db);
+ ds = os->os_dsl_dataset;
+ tx = os->os_synctx;
+
+ (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);
+
+ drp = &db->db_last_dirty;
+ while ((dr = *drp) != db->db_data_pending)
+ drp = &dr->dr_next;
+ ASSERT(!list_link_active(&dr->dr_dirty_node));
+ ASSERT(dr->dr_txg == txg);
+ ASSERT(dr->dr_dbuf == db);
+ ASSERT(dr->dr_next == NULL);
+ *drp = dr->dr_next;
+
+#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->dn_phys->dn_spill);
+ 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)
+ VERIFY(arc_buf_remove_ref(dr->dt.dl.dr_data,
+ db) == 1);
+ else if (!arc_released(db->db_buf))
+ arc_set_callback(db->db_buf, dbuf_do_evict, 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 =
+ dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
+ ASSERT3U(BP_GET_LSIZE(db->db_blkptr), ==,
+ db->db.db_size);
+ ASSERT3U(dn->dn_phys->dn_maxblkid
+ >> (db->db_level * epbs), >=, db->db_blkid);
+ arc_set_callback(db->db_buf, dbuf_do_evict, db);
+ }
+ DB_DNODE_EXIT(db);
+ mutex_destroy(&dr->dt.di.dr_mtx);
+ list_destroy(&dr->dt.di.dr_children);
+ }
+ kmem_free(dr, sizeof (dbuf_dirty_record_t));
+
+ 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)txg);
+}
+
+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);
+}
+
+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_t zb;
+ zio_prop_t zp;
+ zio_t *zio;
+ int wp_flag = 0;
+
+ 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);
+ }
+ }
+ }
+
+ if (parent != dn->dn_dbuf) {
+ ASSERT(parent && parent->db_data_pending);
+ ASSERT(db->db_level == parent->db_level-1);
+ ASSERT(arc_released(parent->db_buf));
+ zio = parent->db_data_pending->dr_zio;
+ } else {
+ 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]);
+ zio = dn->dn_zio;
+ }
+
+ ASSERT(db->db_level == 0 || data == db->db_buf);
+ ASSERT3U(db->db_blkptr->blk_birth, <=, txg);
+ ASSERT(zio);
+
+ 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);
+
+ if (db->db_level == 0 && dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
+ ASSERT(db->db_state != DB_NOFILL);
+ dr->dr_zio = zio_write(zio, os->os_spa, txg,
+ db->db_blkptr, data->b_data, arc_buf_size(data), &zp,
+ dbuf_write_override_ready, 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);
+ mutex_exit(&db->db_mtx);
+ } else if (db->db_state == DB_NOFILL) {
+ ASSERT(zp.zp_checksum == ZIO_CHECKSUM_OFF);
+ dr->dr_zio = zio_write(zio, os->os_spa, txg,
+ db->db_blkptr, NULL, db->db.db_size, &zp,
+ dbuf_write_nofill_ready, dbuf_write_nofill_done, db,
+ ZIO_PRIORITY_ASYNC_WRITE,
+ ZIO_FLAG_MUSTSUCCEED | ZIO_FLAG_NODATA, &zb);
+ } else {
+ ASSERT(arc_released(data));
+ dr->dr_zio = arc_write(zio, os->os_spa, txg,
+ db->db_blkptr, data, DBUF_IS_L2CACHEABLE(db), &zp,
+ dbuf_write_ready, dbuf_write_done, db,
+ ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
+ }
+}