zap_leaf.h revision da6c28aaf62fa55f0fdb8004aa40f88f23bf53f0
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26#ifndef	_SYS_ZAP_LEAF_H
27#define	_SYS_ZAP_LEAF_H
28
29#pragma ident	"%Z%%M%	%I%	%E% SMI"
30
31#ifdef	__cplusplus
32extern "C" {
33#endif
34
35struct zap;
36
37#define	ZAP_LEAF_MAGIC 0x2AB1EAF
38
39/* chunk size = 24 bytes */
40#define	ZAP_LEAF_CHUNKSIZE 24
41
42/*
43 * The amount of space available for chunks is:
44 * block size (1<<l->l_bs) - hash entry size (2) * number of hash
45 * entries - header space (2*chunksize)
46 */
47#define	ZAP_LEAF_NUMCHUNKS(l) \
48	(((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
49	ZAP_LEAF_CHUNKSIZE - 2)
50
51/*
52 * The amount of space within the chunk available for the array is:
53 * chunk size - space for type (1) - space for next pointer (2)
54 */
55#define	ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
56
57#define	ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
58	(((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)
59
60/*
61 * Low water mark:  when there are only this many chunks free, start
62 * growing the ptrtbl.  Ideally, this should be larger than a
63 * "reasonably-sized" entry.  20 chunks is more than enough for the
64 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
65 * while still being only around 3% for 16k blocks.
66 */
67#define	ZAP_LEAF_LOW_WATER (20)
68
69/*
70 * The leaf hash table has block size / 2^5 (32) number of entries,
71 * which should be more than enough for the maximum number of entries,
72 * which is less than block size / CHUNKSIZE (24) / minimum number of
73 * chunks per entry (3).
74 */
75#define	ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
76#define	ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))
77
78/*
79 * The chunks start immediately after the hash table.  The end of the
80 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
81 * chunk_t.
82 */
83#define	ZAP_LEAF_CHUNK(l, idx) \
84	((zap_leaf_chunk_t *) \
85	((l)->l_phys->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
86#define	ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)
87
88typedef enum zap_chunk_type {
89	ZAP_CHUNK_FREE = 253,
90	ZAP_CHUNK_ENTRY = 252,
91	ZAP_CHUNK_ARRAY = 251,
92	ZAP_CHUNK_TYPE_MAX = 250
93} zap_chunk_type_t;
94
95#define	ZLF_ENTRIES_CDSORTED (1<<0)
96
97/*
98 * TAKE NOTE:
99 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
100 */
101typedef struct zap_leaf_phys {
102	struct zap_leaf_header {
103		uint64_t lh_block_type;		/* ZBT_LEAF */
104		uint64_t lh_pad1;
105		uint64_t lh_prefix;		/* hash prefix of this leaf */
106		uint32_t lh_magic;		/* ZAP_LEAF_MAGIC */
107		uint16_t lh_nfree;		/* number free chunks */
108		uint16_t lh_nentries;		/* number of entries */
109		uint16_t lh_prefix_len;		/* num bits used to id this */
110
111/* above is accessable to zap, below is zap_leaf private */
112
113		uint16_t lh_freelist;		/* chunk head of free list */
114		uint8_t lh_flags;		/* ZLF_* flags */
115		uint8_t lh_pad2[11];
116	} l_hdr; /* 2 24-byte chunks */
117
118	/*
119	 * The header is followed by a hash table with
120	 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
121	 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
122	 * zap_leaf_chunk structures.  These structures are accessed
123	 * with the ZAP_LEAF_CHUNK() macro.
124	 */
125
126	uint16_t l_hash[1];
127} zap_leaf_phys_t;
128
129typedef union zap_leaf_chunk {
130	struct zap_leaf_entry {
131		uint8_t le_type; 		/* always ZAP_CHUNK_ENTRY */
132		uint8_t le_int_size;		/* size of ints */
133		uint16_t le_next;		/* next entry in hash chain */
134		uint16_t le_name_chunk;		/* first chunk of the name */
135		uint16_t le_name_length;	/* bytes in name, incl null */
136		uint16_t le_value_chunk;	/* first chunk of the value */
137		uint16_t le_value_length;	/* value length in ints */
138		uint32_t le_cd;			/* collision differentiator */
139		uint64_t le_hash;		/* hash value of the name */
140	} l_entry;
141	struct zap_leaf_array {
142		uint8_t la_type;		/* always ZAP_CHUNK_ARRAY */
143		uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
144		uint16_t la_next;		/* next blk or CHAIN_END */
145	} l_array;
146	struct zap_leaf_free {
147		uint8_t lf_type;		/* always ZAP_CHUNK_FREE */
148		uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
149		uint16_t lf_next;	/* next in free list, or CHAIN_END */
150	} l_free;
151} zap_leaf_chunk_t;
152
153typedef struct zap_leaf {
154	krwlock_t l_rwlock; 		/* only used on head of chain */
155	uint64_t l_blkid;		/* 1<<ZAP_BLOCK_SHIFT byte block off */
156	int l_bs;			/* block size shift */
157	dmu_buf_t *l_dbuf;
158	zap_leaf_phys_t *l_phys;
159} zap_leaf_t;
160
161
162typedef struct zap_entry_handle {
163	/* below is set by zap_leaf.c and is public to zap.c */
164	uint64_t zeh_num_integers;
165	uint64_t zeh_hash;
166	uint32_t zeh_cd;
167	uint8_t zeh_integer_size;
168
169	/* below is private to zap_leaf.c */
170	uint16_t zeh_fakechunk;
171	uint16_t *zeh_chunkp;
172	zap_leaf_t *zeh_leaf;
173} zap_entry_handle_t;
174
175/*
176 * Return a handle to the named entry, or ENOENT if not found.  The hash
177 * value must equal zap_hash(name).
178 */
179extern int zap_leaf_lookup(zap_leaf_t *l,
180    zap_name_t *zn, zap_entry_handle_t *zeh);
181
182/*
183 * Return a handle to the entry with this hash+cd, or the entry with the
184 * next closest hash+cd.
185 */
186extern int zap_leaf_lookup_closest(zap_leaf_t *l,
187    uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
188
189/*
190 * Read the first num_integers in the attribute.  Integer size
191 * conversion will be done without sign extension.  Return EINVAL if
192 * integer_size is too small.  Return EOVERFLOW if there are more than
193 * num_integers in the attribute.
194 */
195extern int zap_entry_read(const zap_entry_handle_t *zeh,
196	uint8_t integer_size, uint64_t num_integers, void *buf);
197
198extern int zap_entry_read_name(const zap_entry_handle_t *zeh,
199	uint16_t buflen, char *buf);
200
201/*
202 * Replace the value of an existing entry.
203 *
204 * zap_entry_update may fail if it runs out of space (ENOSPC).
205 */
206extern int zap_entry_update(zap_entry_handle_t *zeh,
207	uint8_t integer_size, uint64_t num_integers, const void *buf);
208
209/*
210 * Remove an entry.
211 */
212extern void zap_entry_remove(zap_entry_handle_t *zeh);
213
214/*
215 * Create an entry. An equal entry must not exist, and this entry must
216 * belong in this leaf (according to its hash value).  Fills in the
217 * entry handle on success.  Returns 0 on success or ENOSPC on failure.
218 */
219extern int zap_entry_create(zap_leaf_t *l,
220	const char *name, uint64_t h, uint32_t cd,
221	uint8_t integer_size, uint64_t num_integers, const void *buf,
222	zap_entry_handle_t *zeh);
223
224/*
225 * Return true if there are additional entries with the same normalized
226 * form.
227 */
228extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
229    zap_name_t *zn, const char *name, zap_t *zap);
230
231/*
232 * Other stuff.
233 */
234
235extern void zap_leaf_init(zap_leaf_t *l, int version);
236extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
237extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, int version);
238extern void zap_leaf_stats(zap_t *zap, zap_leaf_t *l, zap_stats_t *zs);
239
240#ifdef	__cplusplus
241}
242#endif
243
244#endif /* _SYS_ZAP_LEAF_H */
245