/*

 * 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.

 */

#ifndef	_SYS_ZAP_H

#define	_SYS_ZAP_H

/*

 * ZAP - ZFS Attribute Processor

 *

 * The ZAP is a module which sits on top of the DMU (Data Management

 * Unit) and implements a higher-level storage primitive using DMU

 * objects.  Its primary consumer is the ZPL (ZFS Posix Layer).

 *

 * A "zapobj" is a DMU object which the ZAP uses to stores attributes.

 * Users should use only zap routines to access a zapobj - they should

 * not access the DMU object directly using DMU routines.

 *

 * The attributes stored in a zapobj are name-value pairs.  The name is

 * a zero-terminated string of up to ZAP_MAXNAMELEN bytes (including

 * terminating NULL).  The value is an array of integers, which may be

 * 1, 2, 4, or 8 bytes long.  The total space used by the array (number

 * of integers * integer length) can be up to ZAP_MAXVALUELEN bytes.

 * Note that an 8-byte integer value can be used to store the location

 * (object number) of another dmu object (which may be itself a zapobj).

 * Note that you can use a zero-length attribute to store a single bit

 * of information - the attribute is present or not.

 *

 * The ZAP routines are thread-safe.  However, you must observe the

 * DMU's restriction that a transaction may not be operated on

 * concurrently.

 *

 * Any of the routines that return an int may return an I/O error (EIO

 * or ECHECKSUM).

 *

 *

 * Implementation / Performance Notes:

 *

 * The ZAP is intended to operate most efficiently on attributes with

 * short (49 bytes or less) names and single 8-byte values, for which

 * the microzap will be used.  The ZAP should be efficient enough so

 * that the user does not need to cache these attributes.

 *

 * The ZAP's locking scheme makes its routines thread-safe.  Operations

 * on different zapobjs will be processed concurrently.  Operations on

 * the same zapobj which only read data will be processed concurrently.

 * Operations on the same zapobj which modify data will be processed

 * concurrently when there are many attributes in the zapobj (because

 * the ZAP uses per-block locking - more than 128 * (number of cpus)

 * small attributes will suffice).

 */

/*

 * We're using zero-terminated byte strings (ie. ASCII or UTF-8 C

 * strings) for the names of attributes, rather than a byte string

 * bounded by an explicit length.  If some day we want to support names

 * in character sets which have embedded zeros (eg. UTF-16, UTF-32),

 * we'll have to add routines for using length-bounded strings.

 */

#include <sys/dmu.h>

#ifdef	__cplusplus

extern "C" {

#endif

/*

 * The matchtype specifies which entry will be accessed.

 * MT_EXACT: only find an exact match (non-normalized)

 * MT_FIRST: find the "first" normalized (case and Unicode

 *     form) match; the designated "first" match will not change as long

 *     as the set of entries with this normalization doesn't change

 * MT_BEST: if there is an exact match, find that, otherwise find the

 *     first normalized match

 */

typedef enum matchtype

{

	MT_EXACT,

	MT_BEST,

	MT_FIRST

} matchtype_t;

typedef enum zap_flags {

	/* Use 64-bit hash value (serialized cursors will always use 64-bits) */

	ZAP_FLAG_HASH64 = 1 << 0,

	/* Key is binary, not string (zap_add_uint64() can be used) */

	ZAP_FLAG_UINT64_KEY = 1 << 1,

	/*

	 * First word of key (which must be an array of uint64) is

	 * already randomly distributed.

	 */

	ZAP_FLAG_PRE_HASHED_KEY = 1 << 2,

} zap_flags_t;

/*

 * Create a new zapobj with no attributes and return its object number.

 * MT_EXACT will cause the zap object to only support MT_EXACT lookups,

 * otherwise any matchtype can be used for lookups.

 *

 * normflags specifies what normalization will be done.  values are:

 * 0: no normalization (legacy on-disk format, supports MT_EXACT matching

 *     only)

 * U8_TEXTPREP_TOLOWER: case normalization will be performed.

 *     MT_FIRST/MT_BEST matching will find entries that match without

 *     regard to case (eg. looking for "foo" can find an entry "Foo").

 * Eventually, other flags will permit unicode normalization as well.

 */

uint64_t zap_create(objset_t *ds, dmu_object_type_t ot,

    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);

uint64_t zap_create_norm(objset_t *ds, int normflags, dmu_object_type_t ot,

    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);

uint64_t zap_create_flags(objset_t *os, int normflags, zap_flags_t flags,

    dmu_object_type_t ot, int leaf_blockshift, int indirect_blockshift,

    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);

/*

 * Create a new zapobj with no attributes from the given (unallocated)

 * object number.

 */

int zap_create_claim(objset_t *ds, uint64_t obj, dmu_object_type_t ot,

    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);

int zap_create_claim_norm(objset_t *ds, uint64_t obj,

    int normflags, dmu_object_type_t ot,

    dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);

/*

 * The zapobj passed in must be a valid ZAP object for all of the

 * following routines.

 */

/*

 * Destroy this zapobj and all its attributes.

 *

 * Frees the object number using dmu_object_free.

 */

int zap_destroy(objset_t *ds, uint64_t zapobj, dmu_tx_t *tx);

/*

 * Manipulate attributes.

 *

 * 'integer_size' is in bytes, and must be 1, 2, 4, or 8.

 */

/*

 * Retrieve the contents of the attribute with the given name.

 *

 * If the requested attribute does not exist, the call will fail and

 * return ENOENT.

 *

 * If 'integer_size' is smaller than the attribute's integer size, the

 * call will fail and return EINVAL.

 *

 * If 'integer_size' is equal to or larger than the attribute's integer

 * size, the call will succeed and return 0.  * When converting to a

 * larger integer size, the integers will be treated as unsigned (ie. no

 * sign-extension will be performed).

 *

 * 'num_integers' is the length (in integers) of 'buf'.

 *

 * If the attribute is longer than the buffer, as many integers as will

 * fit will be transferred to 'buf'.  If the entire attribute was not

 * transferred, the call will return EOVERFLOW.

 *

 * If rn_len is nonzero, realname will be set to the name of the found

 * entry (which may be different from the requested name if matchtype is

 * not MT_EXACT).

 *

 * If normalization_conflictp is not NULL, it will be set if there is

 * another name with the same case/unicode normalized form.

 */

int zap_lookup(objset_t *ds, uint64_t zapobj, const char *name,

    uint64_t integer_size, uint64_t num_integers, void *buf);

int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,

    uint64_t integer_size, uint64_t num_integers, void *buf,

    matchtype_t mt, char *realname, int rn_len,

    boolean_t *normalization_conflictp);

int zap_lookup_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,

    int key_numints, uint64_t integer_size, uint64_t num_integers, void *buf);

int zap_contains(objset_t *ds, uint64_t zapobj, const char *name);

int zap_prefetch_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,

    int key_numints);

int zap_count_write(objset_t *os, uint64_t zapobj, const char *name,

    int add, uint64_t *towrite, uint64_t *tooverwrite);

/*

 * Create an attribute with the given name and value.

 *

 * If an attribute with the given name already exists, the call will

 * fail and return EEXIST.

 */

int zap_add(objset_t *ds, uint64_t zapobj, const char *key,

    int integer_size, uint64_t num_integers,

    const void *val, dmu_tx_t *tx);

int zap_add_uint64(objset_t *ds, uint64_t zapobj, const uint64_t *key,

    int key_numints, int integer_size, uint64_t num_integers,

    const void *val, dmu_tx_t *tx);

/*

 * Set the attribute with the given name to the given value.  If an

 * attribute with the given name does not exist, it will be created.  If

 * an attribute with the given name already exists, the previous value

 * will be overwritten.  The integer_size may be different from the

 * existing attribute's integer size, in which case the attribute's

 * integer size will be updated to the new value.

 */

int zap_update(objset_t *ds, uint64_t zapobj, const char *name,

    int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);

int zap_update_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,

    int key_numints,

    int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx);

/*

 * Get the length (in integers) and the integer size of the specified

 * attribute.

 *

 * If the requested attribute does not exist, the call will fail and

 * return ENOENT.

 */

int zap_length(objset_t *ds, uint64_t zapobj, const char *name,

    uint64_t *integer_size, uint64_t *num_integers);

int zap_length_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,

    int key_numints, uint64_t *integer_size, uint64_t *num_integers);

/*

 * Remove the specified attribute.

 *

 * If the specified attribute does not exist, the call will fail and

 * return ENOENT.

 */

int zap_remove(objset_t *ds, uint64_t zapobj, const char *name, dmu_tx_t *tx);

int zap_remove_norm(objset_t *ds, uint64_t zapobj, const char *name,

    matchtype_t mt, dmu_tx_t *tx);

int zap_remove_uint64(objset_t *os, uint64_t zapobj, const uint64_t *key,

    int key_numints, dmu_tx_t *tx);

/*

 * Returns (in *count) the number of attributes in the specified zap

 * object.

 */

int zap_count(objset_t *ds, uint64_t zapobj, uint64_t *count);

/*

 * Returns (in name) the name of the entry whose (value & mask)

 * (za_first_integer) is value, or ENOENT if not found.  The string

 * pointed to by name must be at least 256 bytes long.  If mask==0, the

 * match must be exact (ie, same as mask=-1ULL).

 */

int zap_value_search(objset_t *os, uint64_t zapobj,

    uint64_t value, uint64_t mask, char *name);

/*

 * Transfer all the entries from fromobj into intoobj.  Only works on

 * int_size=8 num_integers=1 values.  Fails if there are any duplicated

 * entries.

 */

int zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx);

/* Same as zap_join, but set the values to 'value'. */

int zap_join_key(objset_t *os, uint64_t fromobj, uint64_t intoobj,

    uint64_t value, dmu_tx_t *tx);

/* Same as zap_join, but add together any duplicated entries. */

int zap_join_increment(objset_t *os, uint64_t fromobj, uint64_t intoobj,

    dmu_tx_t *tx);

/*

 * Manipulate entries where the name + value are the "same" (the name is

 * a stringified version of the value).

 */

int zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);

int zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx);

int zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value);

int zap_increment_int(objset_t *os, uint64_t obj, uint64_t key, int64_t delta,

    dmu_tx_t *tx);

/* Here the key is an int and the value is a different int. */

int zap_add_int_key(objset_t *os, uint64_t obj,

    uint64_t key, uint64_t value, dmu_tx_t *tx);

int zap_lookup_int_key(objset_t *os, uint64_t obj,

    uint64_t key, uint64_t *valuep);

int zap_increment(objset_t *os, uint64_t obj, const char *name, int64_t delta,

    dmu_tx_t *tx);

struct zap;

struct zap_leaf;

typedef struct zap_cursor {

	/* This structure is opaque! */

	objset_t *zc_objset;

	struct zap *zc_zap;

	struct zap_leaf *zc_leaf;

	uint64_t zc_zapobj;

	uint64_t zc_serialized;

	uint64_t zc_hash;

	uint32_t zc_cd;

} zap_cursor_t;

typedef struct {

	int za_integer_length;

	/*

	 * za_normalization_conflict will be set if there are additional

	 * entries with this normalized form (eg, "foo" and "Foo").

	 */

	boolean_t za_normalization_conflict;

	uint64_t za_num_integers;

	uint64_t za_first_integer;	/* no sign extension for <8byte ints */

	char za_name[MAXNAMELEN];

} zap_attribute_t;

/*

 * The interface for listing all the attributes of a zapobj can be

 * thought of as cursor moving down a list of the attributes one by

 * one.  The cookie returned by the zap_cursor_serialize routine is

 * persistent across system calls (and across reboot, even).

 */

/*

 * Initialize a zap cursor, pointing to the "first" attribute of the

 * zapobj.  You must _fini the cursor when you are done with it.

 */

void zap_cursor_init(zap_cursor_t *zc, objset_t *ds, uint64_t zapobj);

void zap_cursor_fini(zap_cursor_t *zc);

/*

 * Get the attribute currently pointed to by the cursor.  Returns

 * ENOENT if at the end of the attributes.

 */

int zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za);

/*

 * Advance the cursor to the next attribute.

 */

void zap_cursor_advance(zap_cursor_t *zc);

/*

 * Get a persistent cookie pointing to the current position of the zap

 * cursor.  The low 4 bits in the cookie are always zero, and thus can

 * be used as to differentiate a serialized cookie from a different type

 * of value.  The cookie will be less than 2^32 as long as there are

 * fewer than 2^22 (4.2 million) entries in the zap object.

 */

uint64_t zap_cursor_serialize(zap_cursor_t *zc);

/*

 * Advance the cursor to the attribute having the given key.

 */

int zap_cursor_move_to_key(zap_cursor_t *zc, const char *name, matchtype_t mt);

/*

 * Initialize a zap cursor pointing to the position recorded by

 * zap_cursor_serialize (in the "serialized" argument).  You can also

 * use a "serialized" argument of 0 to start at the beginning of the

 * zapobj (ie.  zap_cursor_init_serialized(..., 0) is equivalent to

 * zap_cursor_init(...).)

 */

void zap_cursor_init_serialized(zap_cursor_t *zc, objset_t *ds,

    uint64_t zapobj, uint64_t serialized);

#define	ZAP_HISTOGRAM_SIZE 10

typedef struct zap_stats {

	/*

	 * Size of the pointer table (in number of entries).

	 * This is always a power of 2, or zero if it's a microzap.

	 * In general, it should be considerably greater than zs_num_leafs.

	 */

	uint64_t zs_ptrtbl_len;

	uint64_t zs_blocksize;		/* size of zap blocks */

	/*

	 * The number of blocks used.  Note that some blocks may be

	 * wasted because old ptrtbl's and large name/value blocks are

	 * not reused.  (Although their space is reclaimed, we don't

	 * reuse those offsets in the object.)

	 */

	uint64_t zs_num_blocks;

	/*

	 * Pointer table values from zap_ptrtbl in the zap_phys_t

	 */

	uint64_t zs_ptrtbl_nextblk;	  /* next (larger) copy start block */

	uint64_t zs_ptrtbl_blks_copied;   /* number source blocks copied */

	uint64_t zs_ptrtbl_zt_blk;	  /* starting block number */

	uint64_t zs_ptrtbl_zt_numblks;    /* number of blocks */

	uint64_t zs_ptrtbl_zt_shift;	  /* bits to index it */

	/*

	 * Values of the other members of the zap_phys_t

	 */

	uint64_t zs_block_type;		/* ZBT_HEADER */

	uint64_t zs_magic;		/* ZAP_MAGIC */

	uint64_t zs_num_leafs;		/* The number of leaf blocks */

	uint64_t zs_num_entries;	/* The number of zap entries */

	uint64_t zs_salt;		/* salt to stir into hash function */

	/*

	 * Histograms.  For all histograms, the last index

	 * (ZAP_HISTOGRAM_SIZE-1) includes any values which are greater

	 * than what can be represented.  For example

	 * zs_leafs_with_n5_entries[ZAP_HISTOGRAM_SIZE-1] is the number

	 * of leafs with more than 45 entries.

	 */

	/*

	 * zs_leafs_with_n_pointers[n] is the number of leafs with

	 * 2^n pointers to it.

	 */

	uint64_t zs_leafs_with_2n_pointers[ZAP_HISTOGRAM_SIZE];

	/*

	 * zs_leafs_with_n_entries[n] is the number of leafs with

	 * [n*5, (n+1)*5) entries.  In the current implementation, there

	 * can be at most 55 entries in any block, but there may be

	 * fewer if the name or value is large, or the block is not

	 * completely full.

	 */

	uint64_t zs_blocks_with_n5_entries[ZAP_HISTOGRAM_SIZE];

	/*

	 * zs_leafs_n_tenths_full[n] is the number of leafs whose

	 * fullness is in the range [n/10, (n+1)/10).

	 */

	uint64_t zs_blocks_n_tenths_full[ZAP_HISTOGRAM_SIZE];

	/*

	 * zs_entries_using_n_chunks[n] is the number of entries which

	 * consume n 24-byte chunks.  (Note, large names/values only use

	 * one chunk, but contribute to zs_num_blocks_large.)

	 */

	uint64_t zs_entries_using_n_chunks[ZAP_HISTOGRAM_SIZE];

	/*

	 * zs_buckets_with_n_entries[n] is the number of buckets (each

	 * leaf has 64 buckets) with n entries.

	 * zs_buckets_with_n_entries[1] should be very close to

	 * zs_num_entries.

	 */

	uint64_t zs_buckets_with_n_entries[ZAP_HISTOGRAM_SIZE];

} zap_stats_t;

/*

 * Get statistics about a ZAP object.  Note: you need to be aware of the

 * internal implementation of the ZAP to correctly interpret some of the

 * statistics.  This interface shouldn't be relied on unless you really

 * know what you're doing.

 */

int zap_get_stats(objset_t *ds, uint64_t zapobj, zap_stats_t *zs);

#ifdef	__cplusplus

}

#endif

#endif	/* _SYS_ZAP_H */