UBUNTU: SAUCE: (noup) Update spl to 0.6.5.9-1, zfs to 0.6.5.9-2

[mirror_ubuntu-artful-kernel.git] / zfs / module / zfs / zap_leaf.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2013, 2014 by Delphix. All rights reserved.
 */

/*
 * The 512-byte leaf is broken into 32 16-byte chunks.
 * chunk number n means l_chunk[n], even though the header precedes it.
 * the names are stored null-terminated.
 */

#include <sys/zio.h>
#include <sys/spa.h>
#include <sys/dmu.h>
#include <sys/zfs_context.h>
#include <sys/fs/zfs.h>
#include <sys/zap.h>
#include <sys/zap_impl.h>
#include <sys/zap_leaf.h>
#include <sys/arc.h>

static uint16_t *zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry);

#define CHAIN_END 0xffff /* end of the chunk chain */

/* half the (current) minimum block size */
#define MAX_ARRAY_BYTES (8<<10)

#define LEAF_HASH(l, h) \
        ((ZAP_LEAF_HASH_NUMENTRIES(l)-1) & \
        ((h) >> \
        (64 - ZAP_LEAF_HASH_SHIFT(l) - zap_leaf_phys(l)->l_hdr.lh_prefix_len)))

#define LEAF_HASH_ENTPTR(l, h) (&zap_leaf_phys(l)->l_hash[LEAF_HASH(l, h)])

extern inline zap_leaf_phys_t *zap_leaf_phys(zap_leaf_t *l);

static void
zap_memset(void *a, int c, size_t n)
{
        char *cp = a;
        char *cpend = cp + n;

        while (cp < cpend)
                *cp++ = c;
}

static void
stv(int len, void *addr, uint64_t value)
{
        switch (len) {
        case 1:
                *(uint8_t *)addr = value;
                return;
        case 2:
                *(uint16_t *)addr = value;
                return;
        case 4:
                *(uint32_t *)addr = value;
                return;
        case 8:
                *(uint64_t *)addr = value;
                return;
        default:
                cmn_err(CE_PANIC, "bad int len %d", len);
        }
}

static uint64_t
ldv(int len, const void *addr)
{
        switch (len) {
        case 1:
                return (*(uint8_t *)addr);
        case 2:
                return (*(uint16_t *)addr);
        case 4:
                return (*(uint32_t *)addr);
        case 8:
                return (*(uint64_t *)addr);
        default:
                cmn_err(CE_PANIC, "bad int len %d", len);
        }
        return (0xFEEDFACEDEADBEEFULL);
}

void
zap_leaf_byteswap(zap_leaf_phys_t *buf, int size)
{
        int i;
        zap_leaf_t l;
        dmu_buf_t l_dbuf;

        l_dbuf.db_data = buf;
        l.l_bs = highbit64(size) - 1;
        l.l_dbuf = &l_dbuf;

        buf->l_hdr.lh_block_type =      BSWAP_64(buf->l_hdr.lh_block_type);
        buf->l_hdr.lh_prefix =          BSWAP_64(buf->l_hdr.lh_prefix);
        buf->l_hdr.lh_magic =           BSWAP_32(buf->l_hdr.lh_magic);
        buf->l_hdr.lh_nfree =           BSWAP_16(buf->l_hdr.lh_nfree);
        buf->l_hdr.lh_nentries =        BSWAP_16(buf->l_hdr.lh_nentries);
        buf->l_hdr.lh_prefix_len =      BSWAP_16(buf->l_hdr.lh_prefix_len);
        buf->l_hdr.lh_freelist =        BSWAP_16(buf->l_hdr.lh_freelist);

        for (i = 0; i < ZAP_LEAF_HASH_NUMENTRIES(&l); i++)
                buf->l_hash[i] = BSWAP_16(buf->l_hash[i]);

        for (i = 0; i < ZAP_LEAF_NUMCHUNKS(&l); i++) {
                zap_leaf_chunk_t *lc = &ZAP_LEAF_CHUNK(&l, i);
                struct zap_leaf_entry *le;

                switch (lc->l_free.lf_type) {
                case ZAP_CHUNK_ENTRY:
                        le = &lc->l_entry;

                        le->le_type =           BSWAP_8(le->le_type);
                        le->le_value_intlen =   BSWAP_8(le->le_value_intlen);
                        le->le_next =           BSWAP_16(le->le_next);
                        le->le_name_chunk =     BSWAP_16(le->le_name_chunk);
                        le->le_name_numints =   BSWAP_16(le->le_name_numints);
                        le->le_value_chunk =    BSWAP_16(le->le_value_chunk);
                        le->le_value_numints =  BSWAP_16(le->le_value_numints);
                        le->le_cd =             BSWAP_32(le->le_cd);
                        le->le_hash =           BSWAP_64(le->le_hash);
                        break;
                case ZAP_CHUNK_FREE:
                        lc->l_free.lf_type =    BSWAP_8(lc->l_free.lf_type);
                        lc->l_free.lf_next =    BSWAP_16(lc->l_free.lf_next);
                        break;
                case ZAP_CHUNK_ARRAY:
                        lc->l_array.la_type =   BSWAP_8(lc->l_array.la_type);
                        lc->l_array.la_next =   BSWAP_16(lc->l_array.la_next);
                        /* la_array doesn't need swapping */
                        break;
                default:
                        cmn_err(CE_PANIC, "bad leaf type %d",
                            lc->l_free.lf_type);
                }
        }
}

void
zap_leaf_init(zap_leaf_t *l, boolean_t sort)
{
        int i;

        l->l_bs = highbit64(l->l_dbuf->db_size) - 1;
        zap_memset(&zap_leaf_phys(l)->l_hdr, 0,
            sizeof (struct zap_leaf_header));
        zap_memset(zap_leaf_phys(l)->l_hash, CHAIN_END,
            2*ZAP_LEAF_HASH_NUMENTRIES(l));
        for (i = 0; i < ZAP_LEAF_NUMCHUNKS(l); i++) {
                ZAP_LEAF_CHUNK(l, i).l_free.lf_type = ZAP_CHUNK_FREE;
                ZAP_LEAF_CHUNK(l, i).l_free.lf_next = i+1;
        }
        ZAP_LEAF_CHUNK(l, ZAP_LEAF_NUMCHUNKS(l)-1).l_free.lf_next = CHAIN_END;
        zap_leaf_phys(l)->l_hdr.lh_block_type = ZBT_LEAF;
        zap_leaf_phys(l)->l_hdr.lh_magic = ZAP_LEAF_MAGIC;
        zap_leaf_phys(l)->l_hdr.lh_nfree = ZAP_LEAF_NUMCHUNKS(l);
        if (sort)
                zap_leaf_phys(l)->l_hdr.lh_flags |= ZLF_ENTRIES_CDSORTED;
}

/*
 * Routines which manipulate leaf chunks (l_chunk[]).
 */

static uint16_t
zap_leaf_chunk_alloc(zap_leaf_t *l)
{
        int chunk;

        ASSERT(zap_leaf_phys(l)->l_hdr.lh_nfree > 0);

        chunk = zap_leaf_phys(l)->l_hdr.lh_freelist;
        ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
        ASSERT3U(ZAP_LEAF_CHUNK(l, chunk).l_free.lf_type, ==, ZAP_CHUNK_FREE);

        zap_leaf_phys(l)->l_hdr.lh_freelist =
            ZAP_LEAF_CHUNK(l, chunk).l_free.lf_next;

        zap_leaf_phys(l)->l_hdr.lh_nfree--;

        return (chunk);
}

static void
zap_leaf_chunk_free(zap_leaf_t *l, uint16_t chunk)
{
        struct zap_leaf_free *zlf = &ZAP_LEAF_CHUNK(l, chunk).l_free;
        ASSERT3U(zap_leaf_phys(l)->l_hdr.lh_nfree, <, ZAP_LEAF_NUMCHUNKS(l));
        ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
        ASSERT(zlf->lf_type != ZAP_CHUNK_FREE);

        zlf->lf_type = ZAP_CHUNK_FREE;
        zlf->lf_next = zap_leaf_phys(l)->l_hdr.lh_freelist;
        bzero(zlf->lf_pad, sizeof (zlf->lf_pad)); /* help it to compress */
        zap_leaf_phys(l)->l_hdr.lh_freelist = chunk;

        zap_leaf_phys(l)->l_hdr.lh_nfree++;
}

/*
 * Routines which manipulate leaf arrays (zap_leaf_array type chunks).
 */

static uint16_t
zap_leaf_array_create(zap_leaf_t *l, const char *buf,
    int integer_size, int num_integers)
{
        uint16_t chunk_head;
        uint16_t *chunkp = &chunk_head;
        int byten = 0;
        uint64_t value = 0;
        int shift = (integer_size-1)*8;
        int len = num_integers;

        ASSERT3U(num_integers * integer_size, <, MAX_ARRAY_BYTES);

        while (len > 0) {
                uint16_t chunk = zap_leaf_chunk_alloc(l);
                struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
                int i;

                la->la_type = ZAP_CHUNK_ARRAY;
                for (i = 0; i < ZAP_LEAF_ARRAY_BYTES; i++) {
                        if (byten == 0)
                                value = ldv(integer_size, buf);
                        la->la_array[i] = value >> shift;
                        value <<= 8;
                        if (++byten == integer_size) {
                                byten = 0;
                                buf += integer_size;
                                if (--len == 0)
                                        break;
                        }
                }

                *chunkp = chunk;
                chunkp = &la->la_next;
        }
        *chunkp = CHAIN_END;

        return (chunk_head);
}

static void
zap_leaf_array_free(zap_leaf_t *l, uint16_t *chunkp)
{
        uint16_t chunk = *chunkp;

        *chunkp = CHAIN_END;

        while (chunk != CHAIN_END) {
                int nextchunk = ZAP_LEAF_CHUNK(l, chunk).l_array.la_next;
                ASSERT3U(ZAP_LEAF_CHUNK(l, chunk).l_array.la_type, ==,
                    ZAP_CHUNK_ARRAY);
                zap_leaf_chunk_free(l, chunk);
                chunk = nextchunk;
        }
}

/* array_len and buf_len are in integers, not bytes */
static void
zap_leaf_array_read(zap_leaf_t *l, uint16_t chunk,
    int array_int_len, int array_len, int buf_int_len, uint64_t buf_len,
    void *buf)
{
        int len = MIN(array_len, buf_len);
        int byten = 0;
        uint64_t value = 0;
        char *p = buf;

        ASSERT3U(array_int_len, <=, buf_int_len);

        /* Fast path for one 8-byte integer */
        if (array_int_len == 8 && buf_int_len == 8 && len == 1) {
                struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
                uint8_t *ip = la->la_array;
                uint64_t *buf64 = buf;

                *buf64 = (uint64_t)ip[0] << 56 | (uint64_t)ip[1] << 48 |
                    (uint64_t)ip[2] << 40 | (uint64_t)ip[3] << 32 |
                    (uint64_t)ip[4] << 24 | (uint64_t)ip[5] << 16 |
                    (uint64_t)ip[6] << 8 | (uint64_t)ip[7];
                return;
        }

        /* Fast path for an array of 1-byte integers (eg. the entry name) */
        if (array_int_len == 1 && buf_int_len == 1 &&
            buf_len > array_len + ZAP_LEAF_ARRAY_BYTES) {
                while (chunk != CHAIN_END) {
                        struct zap_leaf_array *la =
                            &ZAP_LEAF_CHUNK(l, chunk).l_array;
                        bcopy(la->la_array, p, ZAP_LEAF_ARRAY_BYTES);
                        p += ZAP_LEAF_ARRAY_BYTES;
                        chunk = la->la_next;
                }
                return;
        }

        while (len > 0) {
                struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
                int i;

                ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
                for (i = 0; i < ZAP_LEAF_ARRAY_BYTES && len > 0; i++) {
                        value = (value << 8) | la->la_array[i];
                        byten++;
                        if (byten == array_int_len) {
                                stv(buf_int_len, p, value);
                                byten = 0;
                                len--;
                                if (len == 0)
                                        return;
                                p += buf_int_len;
                        }
                }
                chunk = la->la_next;
        }
}

static boolean_t
zap_leaf_array_match(zap_leaf_t *l, zap_name_t *zn,
    int chunk, int array_numints)
{
        int bseen = 0;

        if (zap_getflags(zn->zn_zap) & ZAP_FLAG_UINT64_KEY) {
                uint64_t *thiskey;
                boolean_t match;

                ASSERT(zn->zn_key_intlen == sizeof (*thiskey));
                thiskey = kmem_alloc(array_numints * sizeof (*thiskey),
                    KM_SLEEP);

                zap_leaf_array_read(l, chunk, sizeof (*thiskey), array_numints,
                    sizeof (*thiskey), array_numints, thiskey);
                match = bcmp(thiskey, zn->zn_key_orig,
                    array_numints * sizeof (*thiskey)) == 0;
                kmem_free(thiskey, array_numints * sizeof (*thiskey));
                return (match);
        }

        ASSERT(zn->zn_key_intlen == 1);
        if (zn->zn_matchtype == MT_FIRST) {
                char *thisname = kmem_alloc(array_numints, KM_SLEEP);
                boolean_t match;

                zap_leaf_array_read(l, chunk, sizeof (char), array_numints,
                    sizeof (char), array_numints, thisname);
                match = zap_match(zn, thisname);
                kmem_free(thisname, array_numints);
                return (match);
        }

        /*
         * Fast path for exact matching.
         * First check that the lengths match, so that we don't read
         * past the end of the zn_key_orig array.
         */
        if (array_numints != zn->zn_key_orig_numints)
                return (B_FALSE);
        while (bseen < array_numints) {
                struct zap_leaf_array *la = &ZAP_LEAF_CHUNK(l, chunk).l_array;
                int toread = MIN(array_numints - bseen, ZAP_LEAF_ARRAY_BYTES);
                ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
                if (bcmp(la->la_array, (char *)zn->zn_key_orig + bseen, toread))
                        break;
                chunk = la->la_next;
                bseen += toread;
        }
        return (bseen == array_numints);
}

/*
 * Routines which manipulate leaf entries.
 */

int
zap_leaf_lookup(zap_leaf_t *l, zap_name_t *zn, zap_entry_handle_t *zeh)
{
        uint16_t *chunkp;
        struct zap_leaf_entry *le;

        ASSERT3U(zap_leaf_phys(l)->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);

again:
        for (chunkp = LEAF_HASH_ENTPTR(l, zn->zn_hash);
            *chunkp != CHAIN_END; chunkp = &le->le_next) {
                uint16_t chunk = *chunkp;
                le = ZAP_LEAF_ENTRY(l, chunk);

                ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
                ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

                if (le->le_hash != zn->zn_hash)
                        continue;

                /*
                 * NB: the entry chain is always sorted by cd on
                 * normalized zap objects, so this will find the
                 * lowest-cd match for MT_FIRST.
                 */
                ASSERT(zn->zn_matchtype == MT_EXACT ||
                    (zap_leaf_phys(l)->l_hdr.lh_flags & ZLF_ENTRIES_CDSORTED));
                if (zap_leaf_array_match(l, zn, le->le_name_chunk,
                    le->le_name_numints)) {
                        zeh->zeh_num_integers = le->le_value_numints;
                        zeh->zeh_integer_size = le->le_value_intlen;
                        zeh->zeh_cd = le->le_cd;
                        zeh->zeh_hash = le->le_hash;
                        zeh->zeh_chunkp = chunkp;
                        zeh->zeh_leaf = l;
                        return (0);
                }
        }

        /*
         * NB: we could of course do this in one pass, but that would be
         * a pain.  We'll see if MT_BEST is even used much.
         */
        if (zn->zn_matchtype == MT_BEST) {
                zn->zn_matchtype = MT_FIRST;
                goto again;
        }

        return (SET_ERROR(ENOENT));
}

/* Return (h1,cd1 >= h2,cd2) */
#define HCD_GTEQ(h1, cd1, h2, cd2) \
        ((h1 > h2) ? TRUE : ((h1 == h2 && cd1 >= cd2) ? TRUE : FALSE))

int
zap_leaf_lookup_closest(zap_leaf_t *l,
    uint64_t h, uint32_t cd, zap_entry_handle_t *zeh)
{
        uint16_t chunk;
        uint64_t besth = -1ULL;
        uint32_t bestcd = -1U;
        uint16_t bestlh = ZAP_LEAF_HASH_NUMENTRIES(l)-1;
        uint16_t lh;
        struct zap_leaf_entry *le;

        ASSERT3U(zap_leaf_phys(l)->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);

        for (lh = LEAF_HASH(l, h); lh <= bestlh; lh++) {
                for (chunk = zap_leaf_phys(l)->l_hash[lh];
                    chunk != CHAIN_END; chunk = le->le_next) {
                        le = ZAP_LEAF_ENTRY(l, chunk);

                        ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
                        ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

                        if (HCD_GTEQ(le->le_hash, le->le_cd, h, cd) &&
                            HCD_GTEQ(besth, bestcd, le->le_hash, le->le_cd)) {
                                ASSERT3U(bestlh, >=, lh);
                                bestlh = lh;
                                besth = le->le_hash;
                                bestcd = le->le_cd;

                                zeh->zeh_num_integers = le->le_value_numints;
                                zeh->zeh_integer_size = le->le_value_intlen;
                                zeh->zeh_cd = le->le_cd;
                                zeh->zeh_hash = le->le_hash;
                                zeh->zeh_fakechunk = chunk;
                                zeh->zeh_chunkp = &zeh->zeh_fakechunk;
                                zeh->zeh_leaf = l;
                        }
                }
        }

        return (bestcd == -1U ? ENOENT : 0);
}

int
zap_entry_read(const zap_entry_handle_t *zeh,
    uint8_t integer_size, uint64_t num_integers, void *buf)
{
        struct zap_leaf_entry *le =
            ZAP_LEAF_ENTRY(zeh->zeh_leaf, *zeh->zeh_chunkp);
        ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

        if (le->le_value_intlen > integer_size)
                return (SET_ERROR(EINVAL));

        zap_leaf_array_read(zeh->zeh_leaf, le->le_value_chunk,
            le->le_value_intlen, le->le_value_numints,
            integer_size, num_integers, buf);

        if (zeh->zeh_num_integers > num_integers)
                return (SET_ERROR(EOVERFLOW));
        return (0);

}

int
zap_entry_read_name(zap_t *zap, const zap_entry_handle_t *zeh, uint16_t buflen,
    char *buf)
{
        struct zap_leaf_entry *le =
            ZAP_LEAF_ENTRY(zeh->zeh_leaf, *zeh->zeh_chunkp);
        ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

        if (zap_getflags(zap) & ZAP_FLAG_UINT64_KEY) {
                zap_leaf_array_read(zeh->zeh_leaf, le->le_name_chunk, 8,
                    le->le_name_numints, 8, buflen / 8, buf);
        } else {
                zap_leaf_array_read(zeh->zeh_leaf, le->le_name_chunk, 1,
                    le->le_name_numints, 1, buflen, buf);
        }
        if (le->le_name_numints > buflen)
                return (SET_ERROR(EOVERFLOW));
        return (0);
}

int
zap_entry_update(zap_entry_handle_t *zeh,
        uint8_t integer_size, uint64_t num_integers, const void *buf)
{
        int delta_chunks;
        zap_leaf_t *l = zeh->zeh_leaf;
        struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, *zeh->zeh_chunkp);

        delta_chunks = ZAP_LEAF_ARRAY_NCHUNKS(num_integers * integer_size) -
            ZAP_LEAF_ARRAY_NCHUNKS(le->le_value_numints * le->le_value_intlen);

        if ((int)zap_leaf_phys(l)->l_hdr.lh_nfree < delta_chunks)
                return (SET_ERROR(EAGAIN));

        zap_leaf_array_free(l, &le->le_value_chunk);
        le->le_value_chunk =
            zap_leaf_array_create(l, buf, integer_size, num_integers);
        le->le_value_numints = num_integers;
        le->le_value_intlen = integer_size;
        return (0);
}

void
zap_entry_remove(zap_entry_handle_t *zeh)
{
        uint16_t entry_chunk;
        struct zap_leaf_entry *le;
        zap_leaf_t *l = zeh->zeh_leaf;

        ASSERT3P(zeh->zeh_chunkp, !=, &zeh->zeh_fakechunk);

        entry_chunk = *zeh->zeh_chunkp;
        le = ZAP_LEAF_ENTRY(l, entry_chunk);
        ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

        zap_leaf_array_free(l, &le->le_name_chunk);
        zap_leaf_array_free(l, &le->le_value_chunk);

        *zeh->zeh_chunkp = le->le_next;
        zap_leaf_chunk_free(l, entry_chunk);

        zap_leaf_phys(l)->l_hdr.lh_nentries--;
}

int
zap_entry_create(zap_leaf_t *l, zap_name_t *zn, uint32_t cd,
    uint8_t integer_size, uint64_t num_integers, const void *buf,
    zap_entry_handle_t *zeh)
{
        uint16_t chunk;
        uint16_t *chunkp;
        struct zap_leaf_entry *le;
        uint64_t valuelen;
        int numchunks;
        uint64_t h = zn->zn_hash;

        valuelen = integer_size * num_integers;

        numchunks = 1 + ZAP_LEAF_ARRAY_NCHUNKS(zn->zn_key_orig_numints *
            zn->zn_key_intlen) + ZAP_LEAF_ARRAY_NCHUNKS(valuelen);
        if (numchunks > ZAP_LEAF_NUMCHUNKS(l))
                return (E2BIG);

        if (cd == ZAP_NEED_CD) {
                /* find the lowest unused cd */
                if (zap_leaf_phys(l)->l_hdr.lh_flags & ZLF_ENTRIES_CDSORTED) {
                        cd = 0;

                        for (chunk = *LEAF_HASH_ENTPTR(l, h);
                            chunk != CHAIN_END; chunk = le->le_next) {
                                le = ZAP_LEAF_ENTRY(l, chunk);
                                if (le->le_cd > cd)
                                        break;
                                if (le->le_hash == h) {
                                        ASSERT3U(cd, ==, le->le_cd);
                                        cd++;
                                }
                        }
                } else {
                        /* old unsorted format; do it the O(n^2) way */
                        for (cd = 0; ; cd++) {
                                for (chunk = *LEAF_HASH_ENTPTR(l, h);
                                    chunk != CHAIN_END; chunk = le->le_next) {
                                        le = ZAP_LEAF_ENTRY(l, chunk);
                                        if (le->le_hash == h &&
                                            le->le_cd == cd) {
                                                break;
                                        }
                                }
                                /* If this cd is not in use, we are good. */
                                if (chunk == CHAIN_END)
                                        break;
                        }
                }
                /*
                 * We would run out of space in a block before we could
                 * store enough entries to run out of CD values.
                 */
                ASSERT3U(cd, <, zap_maxcd(zn->zn_zap));
        }

        if (zap_leaf_phys(l)->l_hdr.lh_nfree < numchunks)
                return (SET_ERROR(EAGAIN));

        /* make the entry */
        chunk = zap_leaf_chunk_alloc(l);
        le = ZAP_LEAF_ENTRY(l, chunk);
        le->le_type = ZAP_CHUNK_ENTRY;
        le->le_name_chunk = zap_leaf_array_create(l, zn->zn_key_orig,
            zn->zn_key_intlen, zn->zn_key_orig_numints);
        le->le_name_numints = zn->zn_key_orig_numints;
        le->le_value_chunk =
            zap_leaf_array_create(l, buf, integer_size, num_integers);
        le->le_value_numints = num_integers;
        le->le_value_intlen = integer_size;
        le->le_hash = h;
        le->le_cd = cd;

        /* link it into the hash chain */
        /* XXX if we did the search above, we could just use that */
        chunkp = zap_leaf_rehash_entry(l, chunk);

        zap_leaf_phys(l)->l_hdr.lh_nentries++;

        zeh->zeh_leaf = l;
        zeh->zeh_num_integers = num_integers;
        zeh->zeh_integer_size = le->le_value_intlen;
        zeh->zeh_cd = le->le_cd;
        zeh->zeh_hash = le->le_hash;
        zeh->zeh_chunkp = chunkp;

        return (0);
}

/*
 * Determine if there is another entry with the same normalized form.
 * For performance purposes, either zn or name must be provided (the
 * other can be NULL).  Note, there usually won't be any hash
 * conflicts, in which case we don't need the concatenated/normalized
 * form of the name.  But all callers have one of these on hand anyway,
 * so might as well take advantage.  A cleaner but slower interface
 * would accept neither argument, and compute the normalized name as
 * needed (using zap_name_alloc(zap_entry_read_name(zeh))).
 */
boolean_t
zap_entry_normalization_conflict(zap_entry_handle_t *zeh, zap_name_t *zn,
    const char *name, zap_t *zap)
{
        uint64_t chunk;
        struct zap_leaf_entry *le;
        boolean_t allocdzn = B_FALSE;

        if (zap->zap_normflags == 0)
                return (B_FALSE);

        for (chunk = *LEAF_HASH_ENTPTR(zeh->zeh_leaf, zeh->zeh_hash);
            chunk != CHAIN_END; chunk = le->le_next) {
                le = ZAP_LEAF_ENTRY(zeh->zeh_leaf, chunk);
                if (le->le_hash != zeh->zeh_hash)
                        continue;
                if (le->le_cd == zeh->zeh_cd)
                        continue;

                if (zn == NULL) {
                        zn = zap_name_alloc(zap, name, MT_FIRST);
                        allocdzn = B_TRUE;
                }
                if (zap_leaf_array_match(zeh->zeh_leaf, zn,
                    le->le_name_chunk, le->le_name_numints)) {
                        if (allocdzn)
                                zap_name_free(zn);
                        return (B_TRUE);
                }
        }
        if (allocdzn)
                zap_name_free(zn);
        return (B_FALSE);
}

/*
 * Routines for transferring entries between leafs.
 */

static uint16_t *
zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry)
{
        struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, entry);
        struct zap_leaf_entry *le2;
        uint16_t *chunkp;

        /*
         * keep the entry chain sorted by cd
         * NB: this will not cause problems for unsorted leafs, though
         * it is unnecessary there.
         */
        for (chunkp = LEAF_HASH_ENTPTR(l, le->le_hash);
            *chunkp != CHAIN_END; chunkp = &le2->le_next) {
                le2 = ZAP_LEAF_ENTRY(l, *chunkp);
                if (le2->le_cd > le->le_cd)
                        break;
        }

        le->le_next = *chunkp;
        *chunkp = entry;
        return (chunkp);
}

static uint16_t
zap_leaf_transfer_array(zap_leaf_t *l, uint16_t chunk, zap_leaf_t *nl)
{
        uint16_t new_chunk;
        uint16_t *nchunkp = &new_chunk;

        while (chunk != CHAIN_END) {
                uint16_t nchunk = zap_leaf_chunk_alloc(nl);
                struct zap_leaf_array *nla =
                    &ZAP_LEAF_CHUNK(nl, nchunk).l_array;
                struct zap_leaf_array *la =
                    &ZAP_LEAF_CHUNK(l, chunk).l_array;
                int nextchunk = la->la_next;

                ASSERT3U(chunk, <, ZAP_LEAF_NUMCHUNKS(l));
                ASSERT3U(nchunk, <, ZAP_LEAF_NUMCHUNKS(l));

                *nla = *la; /* structure assignment */

                zap_leaf_chunk_free(l, chunk);
                chunk = nextchunk;
                *nchunkp = nchunk;
                nchunkp = &nla->la_next;
        }
        *nchunkp = CHAIN_END;
        return (new_chunk);
}

static void
zap_leaf_transfer_entry(zap_leaf_t *l, int entry, zap_leaf_t *nl)
{
        struct zap_leaf_entry *le, *nle;
        uint16_t chunk;

        le = ZAP_LEAF_ENTRY(l, entry);
        ASSERT3U(le->le_type, ==, ZAP_CHUNK_ENTRY);

        chunk = zap_leaf_chunk_alloc(nl);
        nle = ZAP_LEAF_ENTRY(nl, chunk);
        *nle = *le; /* structure assignment */

        (void) zap_leaf_rehash_entry(nl, chunk);

        nle->le_name_chunk = zap_leaf_transfer_array(l, le->le_name_chunk, nl);
        nle->le_value_chunk =
            zap_leaf_transfer_array(l, le->le_value_chunk, nl);

        zap_leaf_chunk_free(l, entry);

        zap_leaf_phys(l)->l_hdr.lh_nentries--;
        zap_leaf_phys(nl)->l_hdr.lh_nentries++;
}

/*
 * Transfer the entries whose hash prefix ends in 1 to the new leaf.
 */
void
zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort)
{
        int i;
        int bit = 64 - 1 - zap_leaf_phys(l)->l_hdr.lh_prefix_len;

        /* set new prefix and prefix_len */
        zap_leaf_phys(l)->l_hdr.lh_prefix <<= 1;
        zap_leaf_phys(l)->l_hdr.lh_prefix_len++;
        zap_leaf_phys(nl)->l_hdr.lh_prefix =
            zap_leaf_phys(l)->l_hdr.lh_prefix | 1;
        zap_leaf_phys(nl)->l_hdr.lh_prefix_len =
            zap_leaf_phys(l)->l_hdr.lh_prefix_len;

        /* break existing hash chains */
        zap_memset(zap_leaf_phys(l)->l_hash, CHAIN_END,
            2*ZAP_LEAF_HASH_NUMENTRIES(l));

        if (sort)
                zap_leaf_phys(l)->l_hdr.lh_flags |= ZLF_ENTRIES_CDSORTED;

        /*
         * Transfer entries whose hash bit 'bit' is set to nl; rehash
         * the remaining entries
         *
         * NB: We could find entries via the hashtable instead. That
         * would be O(hashents+numents) rather than O(numblks+numents),
         * but this accesses memory more sequentially, and when we're
         * called, the block is usually pretty full.
         */
        for (i = 0; i < ZAP_LEAF_NUMCHUNKS(l); i++) {
                struct zap_leaf_entry *le = ZAP_LEAF_ENTRY(l, i);
                if (le->le_type != ZAP_CHUNK_ENTRY)
                        continue;

                if (le->le_hash & (1ULL << bit))
                        zap_leaf_transfer_entry(l, i, nl);
                else
                        (void) zap_leaf_rehash_entry(l, i);
        }
}

void
zap_leaf_stats(zap_t *zap, zap_leaf_t *l, zap_stats_t *zs)
{
        int i, n;

        n = zap_f_phys(zap)->zap_ptrtbl.zt_shift -
            zap_leaf_phys(l)->l_hdr.lh_prefix_len;
        n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
        zs->zs_leafs_with_2n_pointers[n]++;


        n = zap_leaf_phys(l)->l_hdr.lh_nentries/5;
        n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
        zs->zs_blocks_with_n5_entries[n]++;

        n = ((1<<FZAP_BLOCK_SHIFT(zap)) -
            zap_leaf_phys(l)->l_hdr.lh_nfree * (ZAP_LEAF_ARRAY_BYTES+1))*10 /
            (1<<FZAP_BLOCK_SHIFT(zap));
        n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
        zs->zs_blocks_n_tenths_full[n]++;

        for (i = 0; i < ZAP_LEAF_HASH_NUMENTRIES(l); i++) {
                int nentries = 0;
                int chunk = zap_leaf_phys(l)->l_hash[i];

                while (chunk != CHAIN_END) {
                        struct zap_leaf_entry *le =
                            ZAP_LEAF_ENTRY(l, chunk);

                        n = 1 + ZAP_LEAF_ARRAY_NCHUNKS(le->le_name_numints) +
                            ZAP_LEAF_ARRAY_NCHUNKS(le->le_value_numints *
                            le->le_value_intlen);
                        n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
                        zs->zs_entries_using_n_chunks[n]++;

                        chunk = le->le_next;
                        nentries++;
                }

                n = nentries;
                n = MIN(n, ZAP_HISTOGRAM_SIZE-1);
                zs->zs_buckets_with_n_entries[n]++;
        }
}