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Diffstat (limited to 'module/zfs/include/sys/zap.h')
| -rw-r--r-- | module/zfs/include/sys/zap.h | 425 |
1 files changed, 425 insertions, 0 deletions
diff --git a/module/zfs/include/sys/zap.h b/module/zfs/include/sys/zap.h new file mode 100644 index 000000000..f88cc068b --- /dev/null +++ b/module/zfs/include/sys/zap.h @@ -0,0 +1,425 @@ +/* + * 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 2008 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#ifndef _SYS_ZAP_H +#define _SYS_ZAP_H + +#pragma ident "%Z%%M% %I% %E% SMI" + +/* + * 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 + +#define ZAP_MAXNAMELEN 256 +#define ZAP_MAXVALUELEN 1024 + +/* + * 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; + +/* + * 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); + +/* + * 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); + +/* + * 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 *name, + 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); + +/* + * 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); + +/* + * 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); + +/* + * 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); + +/* + * 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); + +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_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); + +/* + * 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 */ |