aboutsummaryrefslogtreecommitdiffstats
path: root/uts/common/fs/zfs/zap.c
diff options
context:
space:
mode:
Diffstat (limited to 'uts/common/fs/zfs/zap.c')
-rw-r--r--uts/common/fs/zfs/zap.c1354
1 files changed, 1354 insertions, 0 deletions
diff --git a/uts/common/fs/zfs/zap.c b/uts/common/fs/zfs/zap.c
new file mode 100644
index 000000000000..288a4d99ab25
--- /dev/null
+++ b/uts/common/fs/zfs/zap.c
@@ -0,0 +1,1354 @@
+/*
+ * 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.
+ */
+
+/*
+ * This file contains the top half of the zfs directory structure
+ * implementation. The bottom half is in zap_leaf.c.
+ *
+ * The zdir is an extendable hash data structure. There is a table of
+ * pointers to buckets (zap_t->zd_data->zd_leafs). The buckets are
+ * each a constant size and hold a variable number of directory entries.
+ * The buckets (aka "leaf nodes") are implemented in zap_leaf.c.
+ *
+ * The pointer table holds a power of 2 number of pointers.
+ * (1<<zap_t->zd_data->zd_phys->zd_prefix_len). The bucket pointed to
+ * by the pointer at index i in the table holds entries whose hash value
+ * has a zd_prefix_len - bit prefix
+ */
+
+#include <sys/spa.h>
+#include <sys/dmu.h>
+#include <sys/zfs_context.h>
+#include <sys/zfs_znode.h>
+#include <sys/fs/zfs.h>
+#include <sys/zap.h>
+#include <sys/refcount.h>
+#include <sys/zap_impl.h>
+#include <sys/zap_leaf.h>
+
+int fzap_default_block_shift = 14; /* 16k blocksize */
+
+static void zap_leaf_pageout(dmu_buf_t *db, void *vl);
+static uint64_t zap_allocate_blocks(zap_t *zap, int nblocks);
+
+
+void
+fzap_byteswap(void *vbuf, size_t size)
+{
+ uint64_t block_type;
+
+ block_type = *(uint64_t *)vbuf;
+
+ if (block_type == ZBT_LEAF || block_type == BSWAP_64(ZBT_LEAF))
+ zap_leaf_byteswap(vbuf, size);
+ else {
+ /* it's a ptrtbl block */
+ byteswap_uint64_array(vbuf, size);
+ }
+}
+
+void
+fzap_upgrade(zap_t *zap, dmu_tx_t *tx, zap_flags_t flags)
+{
+ dmu_buf_t *db;
+ zap_leaf_t *l;
+ int i;
+ zap_phys_t *zp;
+
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+ zap->zap_ismicro = FALSE;
+
+ (void) dmu_buf_update_user(zap->zap_dbuf, zap, zap,
+ &zap->zap_f.zap_phys, zap_evict);
+
+ mutex_init(&zap->zap_f.zap_num_entries_mtx, 0, 0, 0);
+ zap->zap_f.zap_block_shift = highbit(zap->zap_dbuf->db_size) - 1;
+
+ zp = zap->zap_f.zap_phys;
+ /*
+ * explicitly zero it since it might be coming from an
+ * initialized microzap
+ */
+ bzero(zap->zap_dbuf->db_data, zap->zap_dbuf->db_size);
+ zp->zap_block_type = ZBT_HEADER;
+ zp->zap_magic = ZAP_MAGIC;
+
+ zp->zap_ptrtbl.zt_shift = ZAP_EMBEDDED_PTRTBL_SHIFT(zap);
+
+ zp->zap_freeblk = 2; /* block 1 will be the first leaf */
+ zp->zap_num_leafs = 1;
+ zp->zap_num_entries = 0;
+ zp->zap_salt = zap->zap_salt;
+ zp->zap_normflags = zap->zap_normflags;
+ zp->zap_flags = flags;
+
+ /* block 1 will be the first leaf */
+ for (i = 0; i < (1<<zp->zap_ptrtbl.zt_shift); i++)
+ ZAP_EMBEDDED_PTRTBL_ENT(zap, i) = 1;
+
+ /*
+ * set up block 1 - the first leaf
+ */
+ VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ 1<<FZAP_BLOCK_SHIFT(zap), FTAG, &db, DMU_READ_NO_PREFETCH));
+ dmu_buf_will_dirty(db, tx);
+
+ l = kmem_zalloc(sizeof (zap_leaf_t), KM_SLEEP);
+ l->l_dbuf = db;
+ l->l_phys = db->db_data;
+
+ zap_leaf_init(l, zp->zap_normflags != 0);
+
+ kmem_free(l, sizeof (zap_leaf_t));
+ dmu_buf_rele(db, FTAG);
+}
+
+static int
+zap_tryupgradedir(zap_t *zap, dmu_tx_t *tx)
+{
+ if (RW_WRITE_HELD(&zap->zap_rwlock))
+ return (1);
+ if (rw_tryupgrade(&zap->zap_rwlock)) {
+ dmu_buf_will_dirty(zap->zap_dbuf, tx);
+ return (1);
+ }
+ return (0);
+}
+
+/*
+ * Generic routines for dealing with the pointer & cookie tables.
+ */
+
+static int
+zap_table_grow(zap_t *zap, zap_table_phys_t *tbl,
+ void (*transfer_func)(const uint64_t *src, uint64_t *dst, int n),
+ dmu_tx_t *tx)
+{
+ uint64_t b, newblk;
+ dmu_buf_t *db_old, *db_new;
+ int err;
+ int bs = FZAP_BLOCK_SHIFT(zap);
+ int hepb = 1<<(bs-4);
+ /* hepb = half the number of entries in a block */
+
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+ ASSERT(tbl->zt_blk != 0);
+ ASSERT(tbl->zt_numblks > 0);
+
+ if (tbl->zt_nextblk != 0) {
+ newblk = tbl->zt_nextblk;
+ } else {
+ newblk = zap_allocate_blocks(zap, tbl->zt_numblks * 2);
+ tbl->zt_nextblk = newblk;
+ ASSERT3U(tbl->zt_blks_copied, ==, 0);
+ dmu_prefetch(zap->zap_objset, zap->zap_object,
+ tbl->zt_blk << bs, tbl->zt_numblks << bs);
+ }
+
+ /*
+ * Copy the ptrtbl from the old to new location.
+ */
+
+ b = tbl->zt_blks_copied;
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (tbl->zt_blk + b) << bs, FTAG, &db_old, DMU_READ_NO_PREFETCH);
+ if (err)
+ return (err);
+
+ /* first half of entries in old[b] go to new[2*b+0] */
+ VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (newblk + 2*b+0) << bs, FTAG, &db_new, DMU_READ_NO_PREFETCH));
+ dmu_buf_will_dirty(db_new, tx);
+ transfer_func(db_old->db_data, db_new->db_data, hepb);
+ dmu_buf_rele(db_new, FTAG);
+
+ /* second half of entries in old[b] go to new[2*b+1] */
+ VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (newblk + 2*b+1) << bs, FTAG, &db_new, DMU_READ_NO_PREFETCH));
+ dmu_buf_will_dirty(db_new, tx);
+ transfer_func((uint64_t *)db_old->db_data + hepb,
+ db_new->db_data, hepb);
+ dmu_buf_rele(db_new, FTAG);
+
+ dmu_buf_rele(db_old, FTAG);
+
+ tbl->zt_blks_copied++;
+
+ dprintf("copied block %llu of %llu\n",
+ tbl->zt_blks_copied, tbl->zt_numblks);
+
+ if (tbl->zt_blks_copied == tbl->zt_numblks) {
+ (void) dmu_free_range(zap->zap_objset, zap->zap_object,
+ tbl->zt_blk << bs, tbl->zt_numblks << bs, tx);
+
+ tbl->zt_blk = newblk;
+ tbl->zt_numblks *= 2;
+ tbl->zt_shift++;
+ tbl->zt_nextblk = 0;
+ tbl->zt_blks_copied = 0;
+
+ dprintf("finished; numblocks now %llu (%lluk entries)\n",
+ tbl->zt_numblks, 1<<(tbl->zt_shift-10));
+ }
+
+ return (0);
+}
+
+static int
+zap_table_store(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t val,
+ dmu_tx_t *tx)
+{
+ int err;
+ uint64_t blk, off;
+ int bs = FZAP_BLOCK_SHIFT(zap);
+ dmu_buf_t *db;
+
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+ ASSERT(tbl->zt_blk != 0);
+
+ dprintf("storing %llx at index %llx\n", val, idx);
+
+ blk = idx >> (bs-3);
+ off = idx & ((1<<(bs-3))-1);
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (tbl->zt_blk + blk) << bs, FTAG, &db, DMU_READ_NO_PREFETCH);
+ if (err)
+ return (err);
+ dmu_buf_will_dirty(db, tx);
+
+ if (tbl->zt_nextblk != 0) {
+ uint64_t idx2 = idx * 2;
+ uint64_t blk2 = idx2 >> (bs-3);
+ uint64_t off2 = idx2 & ((1<<(bs-3))-1);
+ dmu_buf_t *db2;
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (tbl->zt_nextblk + blk2) << bs, FTAG, &db2,
+ DMU_READ_NO_PREFETCH);
+ if (err) {
+ dmu_buf_rele(db, FTAG);
+ return (err);
+ }
+ dmu_buf_will_dirty(db2, tx);
+ ((uint64_t *)db2->db_data)[off2] = val;
+ ((uint64_t *)db2->db_data)[off2+1] = val;
+ dmu_buf_rele(db2, FTAG);
+ }
+
+ ((uint64_t *)db->db_data)[off] = val;
+ dmu_buf_rele(db, FTAG);
+
+ return (0);
+}
+
+static int
+zap_table_load(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t *valp)
+{
+ uint64_t blk, off;
+ int err;
+ dmu_buf_t *db;
+ int bs = FZAP_BLOCK_SHIFT(zap);
+
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+ blk = idx >> (bs-3);
+ off = idx & ((1<<(bs-3))-1);
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (tbl->zt_blk + blk) << bs, FTAG, &db, DMU_READ_NO_PREFETCH);
+ if (err)
+ return (err);
+ *valp = ((uint64_t *)db->db_data)[off];
+ dmu_buf_rele(db, FTAG);
+
+ if (tbl->zt_nextblk != 0) {
+ /*
+ * read the nextblk for the sake of i/o error checking,
+ * so that zap_table_load() will catch errors for
+ * zap_table_store.
+ */
+ blk = (idx*2) >> (bs-3);
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (tbl->zt_nextblk + blk) << bs, FTAG, &db,
+ DMU_READ_NO_PREFETCH);
+ dmu_buf_rele(db, FTAG);
+ }
+ return (err);
+}
+
+/*
+ * Routines for growing the ptrtbl.
+ */
+
+static void
+zap_ptrtbl_transfer(const uint64_t *src, uint64_t *dst, int n)
+{
+ int i;
+ for (i = 0; i < n; i++) {
+ uint64_t lb = src[i];
+ dst[2*i+0] = lb;
+ dst[2*i+1] = lb;
+ }
+}
+
+static int
+zap_grow_ptrtbl(zap_t *zap, dmu_tx_t *tx)
+{
+ /*
+ * The pointer table should never use more hash bits than we
+ * have (otherwise we'd be using useless zero bits to index it).
+ * If we are within 2 bits of running out, stop growing, since
+ * this is already an aberrant condition.
+ */
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_shift >= zap_hashbits(zap) - 2)
+ return (ENOSPC);
+
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+ /*
+ * We are outgrowing the "embedded" ptrtbl (the one
+ * stored in the header block). Give it its own entire
+ * block, which will double the size of the ptrtbl.
+ */
+ uint64_t newblk;
+ dmu_buf_t *db_new;
+ int err;
+
+ ASSERT3U(zap->zap_f.zap_phys->zap_ptrtbl.zt_shift, ==,
+ ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
+ ASSERT3U(zap->zap_f.zap_phys->zap_ptrtbl.zt_blk, ==, 0);
+
+ newblk = zap_allocate_blocks(zap, 1);
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ newblk << FZAP_BLOCK_SHIFT(zap), FTAG, &db_new,
+ DMU_READ_NO_PREFETCH);
+ if (err)
+ return (err);
+ dmu_buf_will_dirty(db_new, tx);
+ zap_ptrtbl_transfer(&ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
+ db_new->db_data, 1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
+ dmu_buf_rele(db_new, FTAG);
+
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_blk = newblk;
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks = 1;
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_shift++;
+
+ ASSERT3U(1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift, ==,
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks <<
+ (FZAP_BLOCK_SHIFT(zap)-3));
+
+ return (0);
+ } else {
+ return (zap_table_grow(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+ zap_ptrtbl_transfer, tx));
+ }
+}
+
+static void
+zap_increment_num_entries(zap_t *zap, int delta, dmu_tx_t *tx)
+{
+ dmu_buf_will_dirty(zap->zap_dbuf, tx);
+ mutex_enter(&zap->zap_f.zap_num_entries_mtx);
+ ASSERT(delta > 0 || zap->zap_f.zap_phys->zap_num_entries >= -delta);
+ zap->zap_f.zap_phys->zap_num_entries += delta;
+ mutex_exit(&zap->zap_f.zap_num_entries_mtx);
+}
+
+static uint64_t
+zap_allocate_blocks(zap_t *zap, int nblocks)
+{
+ uint64_t newblk;
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+ newblk = zap->zap_f.zap_phys->zap_freeblk;
+ zap->zap_f.zap_phys->zap_freeblk += nblocks;
+ return (newblk);
+}
+
+static zap_leaf_t *
+zap_create_leaf(zap_t *zap, dmu_tx_t *tx)
+{
+ void *winner;
+ zap_leaf_t *l = kmem_alloc(sizeof (zap_leaf_t), KM_SLEEP);
+
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+
+ rw_init(&l->l_rwlock, 0, 0, 0);
+ rw_enter(&l->l_rwlock, RW_WRITER);
+ l->l_blkid = zap_allocate_blocks(zap, 1);
+ l->l_dbuf = NULL;
+ l->l_phys = NULL;
+
+ VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ l->l_blkid << FZAP_BLOCK_SHIFT(zap), NULL, &l->l_dbuf,
+ DMU_READ_NO_PREFETCH));
+ winner = dmu_buf_set_user(l->l_dbuf, l, &l->l_phys, zap_leaf_pageout);
+ ASSERT(winner == NULL);
+ dmu_buf_will_dirty(l->l_dbuf, tx);
+
+ zap_leaf_init(l, zap->zap_normflags != 0);
+
+ zap->zap_f.zap_phys->zap_num_leafs++;
+
+ return (l);
+}
+
+int
+fzap_count(zap_t *zap, uint64_t *count)
+{
+ ASSERT(!zap->zap_ismicro);
+ mutex_enter(&zap->zap_f.zap_num_entries_mtx); /* unnecessary */
+ *count = zap->zap_f.zap_phys->zap_num_entries;
+ mutex_exit(&zap->zap_f.zap_num_entries_mtx);
+ return (0);
+}
+
+/*
+ * Routines for obtaining zap_leaf_t's
+ */
+
+void
+zap_put_leaf(zap_leaf_t *l)
+{
+ rw_exit(&l->l_rwlock);
+ dmu_buf_rele(l->l_dbuf, NULL);
+}
+
+_NOTE(ARGSUSED(0))
+static void
+zap_leaf_pageout(dmu_buf_t *db, void *vl)
+{
+ zap_leaf_t *l = vl;
+
+ rw_destroy(&l->l_rwlock);
+ kmem_free(l, sizeof (zap_leaf_t));
+}
+
+static zap_leaf_t *
+zap_open_leaf(uint64_t blkid, dmu_buf_t *db)
+{
+ zap_leaf_t *l, *winner;
+
+ ASSERT(blkid != 0);
+
+ l = kmem_alloc(sizeof (zap_leaf_t), KM_SLEEP);
+ rw_init(&l->l_rwlock, 0, 0, 0);
+ rw_enter(&l->l_rwlock, RW_WRITER);
+ l->l_blkid = blkid;
+ l->l_bs = highbit(db->db_size)-1;
+ l->l_dbuf = db;
+ l->l_phys = NULL;
+
+ winner = dmu_buf_set_user(db, l, &l->l_phys, zap_leaf_pageout);
+
+ rw_exit(&l->l_rwlock);
+ if (winner != NULL) {
+ /* someone else set it first */
+ zap_leaf_pageout(NULL, l);
+ l = winner;
+ }
+
+ /*
+ * lhr_pad was previously used for the next leaf in the leaf
+ * chain. There should be no chained leafs (as we have removed
+ * support for them).
+ */
+ ASSERT3U(l->l_phys->l_hdr.lh_pad1, ==, 0);
+
+ /*
+ * There should be more hash entries than there can be
+ * chunks to put in the hash table
+ */
+ ASSERT3U(ZAP_LEAF_HASH_NUMENTRIES(l), >, ZAP_LEAF_NUMCHUNKS(l) / 3);
+
+ /* The chunks should begin at the end of the hash table */
+ ASSERT3P(&ZAP_LEAF_CHUNK(l, 0), ==,
+ &l->l_phys->l_hash[ZAP_LEAF_HASH_NUMENTRIES(l)]);
+
+ /* The chunks should end at the end of the block */
+ ASSERT3U((uintptr_t)&ZAP_LEAF_CHUNK(l, ZAP_LEAF_NUMCHUNKS(l)) -
+ (uintptr_t)l->l_phys, ==, l->l_dbuf->db_size);
+
+ return (l);
+}
+
+static int
+zap_get_leaf_byblk(zap_t *zap, uint64_t blkid, dmu_tx_t *tx, krw_t lt,
+ zap_leaf_t **lp)
+{
+ dmu_buf_t *db;
+ zap_leaf_t *l;
+ int bs = FZAP_BLOCK_SHIFT(zap);
+ int err;
+
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ blkid << bs, NULL, &db, DMU_READ_NO_PREFETCH);
+ if (err)
+ return (err);
+
+ ASSERT3U(db->db_object, ==, zap->zap_object);
+ ASSERT3U(db->db_offset, ==, blkid << bs);
+ ASSERT3U(db->db_size, ==, 1 << bs);
+ ASSERT(blkid != 0);
+
+ l = dmu_buf_get_user(db);
+
+ if (l == NULL)
+ l = zap_open_leaf(blkid, db);
+
+ rw_enter(&l->l_rwlock, lt);
+ /*
+ * Must lock before dirtying, otherwise l->l_phys could change,
+ * causing ASSERT below to fail.
+ */
+ if (lt == RW_WRITER)
+ dmu_buf_will_dirty(db, tx);
+ ASSERT3U(l->l_blkid, ==, blkid);
+ ASSERT3P(l->l_dbuf, ==, db);
+ ASSERT3P(l->l_phys, ==, l->l_dbuf->db_data);
+ ASSERT3U(l->l_phys->l_hdr.lh_block_type, ==, ZBT_LEAF);
+ ASSERT3U(l->l_phys->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);
+
+ *lp = l;
+ return (0);
+}
+
+static int
+zap_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t *valp)
+{
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+ ASSERT3U(idx, <,
+ (1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift));
+ *valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);
+ return (0);
+ } else {
+ return (zap_table_load(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+ idx, valp));
+ }
+}
+
+static int
+zap_set_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t blk, dmu_tx_t *tx)
+{
+ ASSERT(tx != NULL);
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk == 0) {
+ ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) = blk;
+ return (0);
+ } else {
+ return (zap_table_store(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+ idx, blk, tx));
+ }
+}
+
+static int
+zap_deref_leaf(zap_t *zap, uint64_t h, dmu_tx_t *tx, krw_t lt, zap_leaf_t **lp)
+{
+ uint64_t idx, blk;
+ int err;
+
+ ASSERT(zap->zap_dbuf == NULL ||
+ zap->zap_f.zap_phys == zap->zap_dbuf->db_data);
+ ASSERT3U(zap->zap_f.zap_phys->zap_magic, ==, ZAP_MAGIC);
+ idx = ZAP_HASH_IDX(h, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+ err = zap_idx_to_blk(zap, idx, &blk);
+ if (err != 0)
+ return (err);
+ err = zap_get_leaf_byblk(zap, blk, tx, lt, lp);
+
+ ASSERT(err || ZAP_HASH_IDX(h, (*lp)->l_phys->l_hdr.lh_prefix_len) ==
+ (*lp)->l_phys->l_hdr.lh_prefix);
+ return (err);
+}
+
+static int
+zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx, zap_leaf_t **lp)
+{
+ zap_t *zap = zn->zn_zap;
+ uint64_t hash = zn->zn_hash;
+ zap_leaf_t *nl;
+ int prefix_diff, i, err;
+ uint64_t sibling;
+ int old_prefix_len = l->l_phys->l_hdr.lh_prefix_len;
+
+ ASSERT3U(old_prefix_len, <=, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+ ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
+ l->l_phys->l_hdr.lh_prefix);
+
+ if (zap_tryupgradedir(zap, tx) == 0 ||
+ old_prefix_len == zap->zap_f.zap_phys->zap_ptrtbl.zt_shift) {
+ /* We failed to upgrade, or need to grow the pointer table */
+ objset_t *os = zap->zap_objset;
+ uint64_t object = zap->zap_object;
+
+ zap_put_leaf(l);
+ zap_unlockdir(zap);
+ err = zap_lockdir(os, object, tx, RW_WRITER,
+ FALSE, FALSE, &zn->zn_zap);
+ zap = zn->zn_zap;
+ if (err)
+ return (err);
+ ASSERT(!zap->zap_ismicro);
+
+ while (old_prefix_len ==
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_shift) {
+ err = zap_grow_ptrtbl(zap, tx);
+ if (err)
+ return (err);
+ }
+
+ err = zap_deref_leaf(zap, hash, tx, RW_WRITER, &l);
+ if (err)
+ return (err);
+
+ if (l->l_phys->l_hdr.lh_prefix_len != old_prefix_len) {
+ /* it split while our locks were down */
+ *lp = l;
+ return (0);
+ }
+ }
+ ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+ ASSERT3U(old_prefix_len, <, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+ ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
+ l->l_phys->l_hdr.lh_prefix);
+
+ prefix_diff = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift -
+ (old_prefix_len + 1);
+ sibling = (ZAP_HASH_IDX(hash, old_prefix_len + 1) | 1) << prefix_diff;
+
+ /* check for i/o errors before doing zap_leaf_split */
+ for (i = 0; i < (1ULL<<prefix_diff); i++) {
+ uint64_t blk;
+ err = zap_idx_to_blk(zap, sibling+i, &blk);
+ if (err)
+ return (err);
+ ASSERT3U(blk, ==, l->l_blkid);
+ }
+
+ nl = zap_create_leaf(zap, tx);
+ zap_leaf_split(l, nl, zap->zap_normflags != 0);
+
+ /* set sibling pointers */
+ for (i = 0; i < (1ULL<<prefix_diff); i++) {
+ err = zap_set_idx_to_blk(zap, sibling+i, nl->l_blkid, tx);
+ ASSERT3U(err, ==, 0); /* we checked for i/o errors above */
+ }
+
+ if (hash & (1ULL << (64 - l->l_phys->l_hdr.lh_prefix_len))) {
+ /* we want the sibling */
+ zap_put_leaf(l);
+ *lp = nl;
+ } else {
+ zap_put_leaf(nl);
+ *lp = l;
+ }
+
+ return (0);
+}
+
+static void
+zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx)
+{
+ zap_t *zap = zn->zn_zap;
+ int shift = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+ int leaffull = (l->l_phys->l_hdr.lh_prefix_len == shift &&
+ l->l_phys->l_hdr.lh_nfree < ZAP_LEAF_LOW_WATER);
+
+ zap_put_leaf(l);
+
+ if (leaffull || zap->zap_f.zap_phys->zap_ptrtbl.zt_nextblk) {
+ int err;
+
+ /*
+ * We are in the middle of growing the pointer table, or
+ * this leaf will soon make us grow it.
+ */
+ if (zap_tryupgradedir(zap, tx) == 0) {
+ objset_t *os = zap->zap_objset;
+ uint64_t zapobj = zap->zap_object;
+
+ zap_unlockdir(zap);
+ err = zap_lockdir(os, zapobj, tx,
+ RW_WRITER, FALSE, FALSE, &zn->zn_zap);
+ zap = zn->zn_zap;
+ if (err)
+ return;
+ }
+
+ /* could have finished growing while our locks were down */
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_shift == shift)
+ (void) zap_grow_ptrtbl(zap, tx);
+ }
+}
+
+static int
+fzap_checkname(zap_name_t *zn)
+{
+ if (zn->zn_key_orig_numints * zn->zn_key_intlen > ZAP_MAXNAMELEN)
+ return (ENAMETOOLONG);
+ return (0);
+}
+
+static int
+fzap_checksize(uint64_t integer_size, uint64_t num_integers)
+{
+ /* Only integer sizes supported by C */
+ switch (integer_size) {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ break;
+ default:
+ return (EINVAL);
+ }
+
+ if (integer_size * num_integers > ZAP_MAXVALUELEN)
+ return (E2BIG);
+
+ return (0);
+}
+
+static int
+fzap_check(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers)
+{
+ int err;
+
+ if ((err = fzap_checkname(zn)) != 0)
+ return (err);
+ return (fzap_checksize(integer_size, num_integers));
+}
+
+/*
+ * Routines for manipulating attributes.
+ */
+int
+fzap_lookup(zap_name_t *zn,
+ uint64_t integer_size, uint64_t num_integers, void *buf,
+ char *realname, int rn_len, boolean_t *ncp)
+{
+ zap_leaf_t *l;
+ int err;
+ zap_entry_handle_t zeh;
+
+ if ((err = fzap_checkname(zn)) != 0)
+ return (err);
+
+ err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
+ if (err != 0)
+ return (err);
+ err = zap_leaf_lookup(l, zn, &zeh);
+ if (err == 0) {
+ if ((err = fzap_checksize(integer_size, num_integers)) != 0) {
+ zap_put_leaf(l);
+ return (err);
+ }
+
+ err = zap_entry_read(&zeh, integer_size, num_integers, buf);
+ (void) zap_entry_read_name(zn->zn_zap, &zeh, rn_len, realname);
+ if (ncp) {
+ *ncp = zap_entry_normalization_conflict(&zeh,
+ zn, NULL, zn->zn_zap);
+ }
+ }
+
+ zap_put_leaf(l);
+ return (err);
+}
+
+int
+fzap_add_cd(zap_name_t *zn,
+ uint64_t integer_size, uint64_t num_integers,
+ const void *val, uint32_t cd, dmu_tx_t *tx)
+{
+ zap_leaf_t *l;
+ int err;
+ zap_entry_handle_t zeh;
+ zap_t *zap = zn->zn_zap;
+
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+ ASSERT(!zap->zap_ismicro);
+ ASSERT(fzap_check(zn, integer_size, num_integers) == 0);
+
+ err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
+ if (err != 0)
+ return (err);
+retry:
+ err = zap_leaf_lookup(l, zn, &zeh);
+ if (err == 0) {
+ err = EEXIST;
+ goto out;
+ }
+ if (err != ENOENT)
+ goto out;
+
+ err = zap_entry_create(l, zn, cd,
+ integer_size, num_integers, val, &zeh);
+
+ if (err == 0) {
+ zap_increment_num_entries(zap, 1, tx);
+ } else if (err == EAGAIN) {
+ err = zap_expand_leaf(zn, l, tx, &l);
+ zap = zn->zn_zap; /* zap_expand_leaf() may change zap */
+ if (err == 0)
+ goto retry;
+ }
+
+out:
+ if (zap != NULL)
+ zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
+ return (err);
+}
+
+int
+fzap_add(zap_name_t *zn,
+ uint64_t integer_size, uint64_t num_integers,
+ const void *val, dmu_tx_t *tx)
+{
+ int err = fzap_check(zn, integer_size, num_integers);
+ if (err != 0)
+ return (err);
+
+ return (fzap_add_cd(zn, integer_size, num_integers,
+ val, ZAP_NEED_CD, tx));
+}
+
+int
+fzap_update(zap_name_t *zn,
+ int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx)
+{
+ zap_leaf_t *l;
+ int err, create;
+ zap_entry_handle_t zeh;
+ zap_t *zap = zn->zn_zap;
+
+ ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+ err = fzap_check(zn, integer_size, num_integers);
+ if (err != 0)
+ return (err);
+
+ err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
+ if (err != 0)
+ return (err);
+retry:
+ err = zap_leaf_lookup(l, zn, &zeh);
+ create = (err == ENOENT);
+ ASSERT(err == 0 || err == ENOENT);
+
+ if (create) {
+ err = zap_entry_create(l, zn, ZAP_NEED_CD,
+ integer_size, num_integers, val, &zeh);
+ if (err == 0)
+ zap_increment_num_entries(zap, 1, tx);
+ } else {
+ err = zap_entry_update(&zeh, integer_size, num_integers, val);
+ }
+
+ if (err == EAGAIN) {
+ err = zap_expand_leaf(zn, l, tx, &l);
+ zap = zn->zn_zap; /* zap_expand_leaf() may change zap */
+ if (err == 0)
+ goto retry;
+ }
+
+ if (zap != NULL)
+ zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
+ return (err);
+}
+
+int
+fzap_length(zap_name_t *zn,
+ uint64_t *integer_size, uint64_t *num_integers)
+{
+ zap_leaf_t *l;
+ int err;
+ zap_entry_handle_t zeh;
+
+ err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
+ if (err != 0)
+ return (err);
+ err = zap_leaf_lookup(l, zn, &zeh);
+ if (err != 0)
+ goto out;
+
+ if (integer_size)
+ *integer_size = zeh.zeh_integer_size;
+ if (num_integers)
+ *num_integers = zeh.zeh_num_integers;
+out:
+ zap_put_leaf(l);
+ return (err);
+}
+
+int
+fzap_remove(zap_name_t *zn, dmu_tx_t *tx)
+{
+ zap_leaf_t *l;
+ int err;
+ zap_entry_handle_t zeh;
+
+ err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, tx, RW_WRITER, &l);
+ if (err != 0)
+ return (err);
+ err = zap_leaf_lookup(l, zn, &zeh);
+ if (err == 0) {
+ zap_entry_remove(&zeh);
+ zap_increment_num_entries(zn->zn_zap, -1, tx);
+ }
+ zap_put_leaf(l);
+ return (err);
+}
+
+void
+fzap_prefetch(zap_name_t *zn)
+{
+ uint64_t idx, blk;
+ zap_t *zap = zn->zn_zap;
+ int bs;
+
+ idx = ZAP_HASH_IDX(zn->zn_hash,
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+ if (zap_idx_to_blk(zap, idx, &blk) != 0)
+ return;
+ bs = FZAP_BLOCK_SHIFT(zap);
+ dmu_prefetch(zap->zap_objset, zap->zap_object, blk << bs, 1 << bs);
+}
+
+/*
+ * Helper functions for consumers.
+ */
+
+int
+zap_value_search(objset_t *os, uint64_t zapobj, uint64_t value, uint64_t mask,
+ char *name)
+{
+ zap_cursor_t zc;
+ zap_attribute_t *za;
+ int err;
+
+ if (mask == 0)
+ mask = -1ULL;
+
+ za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
+ for (zap_cursor_init(&zc, os, zapobj);
+ (err = zap_cursor_retrieve(&zc, za)) == 0;
+ zap_cursor_advance(&zc)) {
+ if ((za->za_first_integer & mask) == (value & mask)) {
+ (void) strcpy(name, za->za_name);
+ break;
+ }
+ }
+ zap_cursor_fini(&zc);
+ kmem_free(za, sizeof (zap_attribute_t));
+ return (err);
+}
+
+int
+zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx)
+{
+ zap_cursor_t zc;
+ zap_attribute_t za;
+ int err;
+
+ for (zap_cursor_init(&zc, os, fromobj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ (void) zap_cursor_advance(&zc)) {
+ if (za.za_integer_length != 8 || za.za_num_integers != 1)
+ return (EINVAL);
+ err = zap_add(os, intoobj, za.za_name,
+ 8, 1, &za.za_first_integer, tx);
+ if (err)
+ return (err);
+ }
+ zap_cursor_fini(&zc);
+ return (0);
+}
+
+int
+zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,
+ uint64_t value, dmu_tx_t *tx)
+{
+ zap_cursor_t zc;
+ zap_attribute_t za;
+ int err;
+
+ for (zap_cursor_init(&zc, os, fromobj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ (void) zap_cursor_advance(&zc)) {
+ if (za.za_integer_length != 8 || za.za_num_integers != 1)
+ return (EINVAL);
+ err = zap_add(os, intoobj, za.za_name,
+ 8, 1, &value, tx);
+ if (err)
+ return (err);
+ }
+ zap_cursor_fini(&zc);
+ return (0);
+}
+
+int
+zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,
+ dmu_tx_t *tx)
+{
+ zap_cursor_t zc;
+ zap_attribute_t za;
+ int err;
+
+ for (zap_cursor_init(&zc, os, fromobj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ (void) zap_cursor_advance(&zc)) {
+ uint64_t delta = 0;
+
+ if (za.za_integer_length != 8 || za.za_num_integers != 1)
+ return (EINVAL);
+
+ err = zap_lookup(os, intoobj, za.za_name, 8, 1, &delta);
+ if (err != 0 && err != ENOENT)
+ return (err);
+ delta += za.za_first_integer;
+ err = zap_update(os, intoobj, za.za_name, 8, 1, &delta, tx);
+ if (err)
+ return (err);
+ }
+ zap_cursor_fini(&zc);
+ return (0);
+}
+
+int
+zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+ return (zap_add(os, obj, name, 8, 1, &value, tx));
+}
+
+int
+zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+ return (zap_remove(os, obj, name, tx));
+}
+
+int
+zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+ return (zap_lookup(os, obj, name, 8, 1, &value));
+}
+
+int
+zap_add_int_key(objset_t *os, uint64_t obj,
+ uint64_t key, uint64_t value, dmu_tx_t *tx)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
+ return (zap_add(os, obj, name, 8, 1, &value, tx));
+}
+
+int
+zap_lookup_int_key(objset_t *os, uint64_t obj, uint64_t key, uint64_t *valuep)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
+ return (zap_lookup(os, obj, name, 8, 1, valuep));
+}
+
+int
+zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,
+ dmu_tx_t *tx)
+{
+ uint64_t value = 0;
+ int err;
+
+ if (delta == 0)
+ return (0);
+
+ err = zap_lookup(os, obj, name, 8, 1, &value);
+ if (err != 0 && err != ENOENT)
+ return (err);
+ value += delta;
+ if (value == 0)
+ err = zap_remove(os, obj, name, tx);
+ else
+ err = zap_update(os, obj, name, 8, 1, &value, tx);
+ return (err);
+}
+
+int
+zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,
+ dmu_tx_t *tx)
+{
+ char name[20];
+
+ (void) snprintf(name, sizeof (name), "%llx", (longlong_t)key);
+ return (zap_increment(os, obj, name, delta, tx));
+}
+
+/*
+ * Routines for iterating over the attributes.
+ */
+
+int
+fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za)
+{
+ int err = ENOENT;
+ zap_entry_handle_t zeh;
+ zap_leaf_t *l;
+
+ /* retrieve the next entry at or after zc_hash/zc_cd */
+ /* if no entry, return ENOENT */
+
+ if (zc->zc_leaf &&
+ (ZAP_HASH_IDX(zc->zc_hash,
+ zc->zc_leaf->l_phys->l_hdr.lh_prefix_len) !=
+ zc->zc_leaf->l_phys->l_hdr.lh_prefix)) {
+ rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
+ zap_put_leaf(zc->zc_leaf);
+ zc->zc_leaf = NULL;
+ }
+
+again:
+ if (zc->zc_leaf == NULL) {
+ err = zap_deref_leaf(zap, zc->zc_hash, NULL, RW_READER,
+ &zc->zc_leaf);
+ if (err != 0)
+ return (err);
+ } else {
+ rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
+ }
+ l = zc->zc_leaf;
+
+ err = zap_leaf_lookup_closest(l, zc->zc_hash, zc->zc_cd, &zeh);
+
+ if (err == ENOENT) {
+ uint64_t nocare =
+ (1ULL << (64 - l->l_phys->l_hdr.lh_prefix_len)) - 1;
+ zc->zc_hash = (zc->zc_hash & ~nocare) + nocare + 1;
+ zc->zc_cd = 0;
+ if (l->l_phys->l_hdr.lh_prefix_len == 0 || zc->zc_hash == 0) {
+ zc->zc_hash = -1ULL;
+ } else {
+ zap_put_leaf(zc->zc_leaf);
+ zc->zc_leaf = NULL;
+ goto again;
+ }
+ }
+
+ if (err == 0) {
+ zc->zc_hash = zeh.zeh_hash;
+ zc->zc_cd = zeh.zeh_cd;
+ za->za_integer_length = zeh.zeh_integer_size;
+ za->za_num_integers = zeh.zeh_num_integers;
+ if (zeh.zeh_num_integers == 0) {
+ za->za_first_integer = 0;
+ } else {
+ err = zap_entry_read(&zeh, 8, 1, &za->za_first_integer);
+ ASSERT(err == 0 || err == EOVERFLOW);
+ }
+ err = zap_entry_read_name(zap, &zeh,
+ sizeof (za->za_name), za->za_name);
+ ASSERT(err == 0);
+
+ za->za_normalization_conflict =
+ zap_entry_normalization_conflict(&zeh,
+ NULL, za->za_name, zap);
+ }
+ rw_exit(&zc->zc_leaf->l_rwlock);
+ return (err);
+}
+
+static void
+zap_stats_ptrtbl(zap_t *zap, uint64_t *tbl, int len, zap_stats_t *zs)
+{
+ int i, err;
+ uint64_t lastblk = 0;
+
+ /*
+ * NB: if a leaf has more pointers than an entire ptrtbl block
+ * can hold, then it'll be accounted for more than once, since
+ * we won't have lastblk.
+ */
+ for (i = 0; i < len; i++) {
+ zap_leaf_t *l;
+
+ if (tbl[i] == lastblk)
+ continue;
+ lastblk = tbl[i];
+
+ err = zap_get_leaf_byblk(zap, tbl[i], NULL, RW_READER, &l);
+ if (err == 0) {
+ zap_leaf_stats(zap, l, zs);
+ zap_put_leaf(l);
+ }
+ }
+}
+
+int
+fzap_cursor_move_to_key(zap_cursor_t *zc, zap_name_t *zn)
+{
+ int err;
+ zap_leaf_t *l;
+ zap_entry_handle_t zeh;
+
+ if (zn->zn_key_orig_numints * zn->zn_key_intlen > ZAP_MAXNAMELEN)
+ return (ENAMETOOLONG);
+
+ err = zap_deref_leaf(zc->zc_zap, zn->zn_hash, NULL, RW_READER, &l);
+ if (err != 0)
+ return (err);
+
+ err = zap_leaf_lookup(l, zn, &zeh);
+ if (err != 0)
+ return (err);
+
+ zc->zc_leaf = l;
+ zc->zc_hash = zeh.zeh_hash;
+ zc->zc_cd = zeh.zeh_cd;
+
+ return (err);
+}
+
+void
+fzap_get_stats(zap_t *zap, zap_stats_t *zs)
+{
+ int bs = FZAP_BLOCK_SHIFT(zap);
+ zs->zs_blocksize = 1ULL << bs;
+
+ /*
+ * Set zap_phys_t fields
+ */
+ zs->zs_num_leafs = zap->zap_f.zap_phys->zap_num_leafs;
+ zs->zs_num_entries = zap->zap_f.zap_phys->zap_num_entries;
+ zs->zs_num_blocks = zap->zap_f.zap_phys->zap_freeblk;
+ zs->zs_block_type = zap->zap_f.zap_phys->zap_block_type;
+ zs->zs_magic = zap->zap_f.zap_phys->zap_magic;
+ zs->zs_salt = zap->zap_f.zap_phys->zap_salt;
+
+ /*
+ * Set zap_ptrtbl fields
+ */
+ zs->zs_ptrtbl_len = 1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+ zs->zs_ptrtbl_nextblk = zap->zap_f.zap_phys->zap_ptrtbl.zt_nextblk;
+ zs->zs_ptrtbl_blks_copied =
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_blks_copied;
+ zs->zs_ptrtbl_zt_blk = zap->zap_f.zap_phys->zap_ptrtbl.zt_blk;
+ zs->zs_ptrtbl_zt_numblks = zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks;
+ zs->zs_ptrtbl_zt_shift = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+ /* the ptrtbl is entirely in the header block. */
+ zap_stats_ptrtbl(zap, &ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
+ 1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap), zs);
+ } else {
+ int b;
+
+ dmu_prefetch(zap->zap_objset, zap->zap_object,
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_blk << bs,
+ zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks << bs);
+
+ for (b = 0; b < zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks;
+ b++) {
+ dmu_buf_t *db;
+ int err;
+
+ err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+ (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk + b) << bs,
+ FTAG, &db, DMU_READ_NO_PREFETCH);
+ if (err == 0) {
+ zap_stats_ptrtbl(zap, db->db_data,
+ 1<<(bs-3), zs);
+ dmu_buf_rele(db, FTAG);
+ }
+ }
+ }
+}
+
+int
+fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
+ uint64_t *tooverwrite)
+{
+ zap_t *zap = zn->zn_zap;
+ zap_leaf_t *l;
+ int err;
+
+ /*
+ * Account for the header block of the fatzap.
+ */
+ if (!add && dmu_buf_freeable(zap->zap_dbuf)) {
+ *tooverwrite += zap->zap_dbuf->db_size;
+ } else {
+ *towrite += zap->zap_dbuf->db_size;
+ }
+
+ /*
+ * Account for the pointer table blocks.
+ * If we are adding we need to account for the following cases :
+ * - If the pointer table is embedded, this operation could force an
+ * external pointer table.
+ * - If this already has an external pointer table this operation
+ * could extend the table.
+ */
+ if (add) {
+ if (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk == 0)
+ *towrite += zap->zap_dbuf->db_size;
+ else
+ *towrite += (zap->zap_dbuf->db_size * 3);
+ }
+
+ /*
+ * Now, check if the block containing leaf is freeable
+ * and account accordingly.
+ */
+ err = zap_deref_leaf(zap, zn->zn_hash, NULL, RW_READER, &l);
+ if (err != 0) {
+ return (err);
+ }
+
+ if (!add && dmu_buf_freeable(l->l_dbuf)) {
+ *tooverwrite += l->l_dbuf->db_size;
+ } else {
+ /*
+ * If this an add operation, the leaf block could split.
+ * Hence, we need to account for an additional leaf block.
+ */
+ *towrite += (add ? 2 : 1) * l->l_dbuf->db_size;
+ }
+
+ zap_put_leaf(l);
+ return (0);
+}