zap_leaf.h revision c1379625401dfbe1c39b79136dd384a571d47fde
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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25#ifndef	_SYS_ZAP_LEAF_H
26#define	_SYS_ZAP_LEAF_H
27
28#include <sys/zap.h>
29
30#ifdef	__cplusplus
31extern "C" {
32#endif
33
34struct zap;
35struct zap_name;
36struct zap_stats;
37
38#define	ZAP_LEAF_MAGIC 0x2AB1EAF
39
40/* chunk size = 24 bytes */
41#define	ZAP_LEAF_CHUNKSIZE 24
42
43/*
44 * The amount of space available for chunks is:
45 * block size (1<<l->l_bs) - hash entry size (2) * number of hash
46 * entries - header space (2*chunksize)
47 */
48#define	ZAP_LEAF_NUMCHUNKS(l) \
49	(((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
50	ZAP_LEAF_CHUNKSIZE - 2)
51
52/*
53 * The amount of space within the chunk available for the array is:
54 * chunk size - space for type (1) - space for next pointer (2)
55 */
56#define	ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
57
58#define	ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
59	(((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)
60
61/*
62 * Low water mark:  when there are only this many chunks free, start
63 * growing the ptrtbl.  Ideally, this should be larger than a
64 * "reasonably-sized" entry.  20 chunks is more than enough for the
65 * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
66 * while still being only around 3% for 16k blocks.
67 */
68#define	ZAP_LEAF_LOW_WATER (20)
69
70/*
71 * The leaf hash table has block size / 2^5 (32) number of entries,
72 * which should be more than enough for the maximum number of entries,
73 * which is less than block size / CHUNKSIZE (24) / minimum number of
74 * chunks per entry (3).
75 */
76#define	ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
77#define	ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))
78
79/*
80 * The chunks start immediately after the hash table.  The end of the
81 * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
82 * chunk_t.
83 */
84#define	ZAP_LEAF_CHUNK(l, idx) \
85	((zap_leaf_chunk_t *) \
86	(zap_leaf_phys(l)->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
87#define	ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)
88
89typedef enum zap_chunk_type {
90	ZAP_CHUNK_FREE = 253,
91	ZAP_CHUNK_ENTRY = 252,
92	ZAP_CHUNK_ARRAY = 251,
93	ZAP_CHUNK_TYPE_MAX = 250
94} zap_chunk_type_t;
95
96#define	ZLF_ENTRIES_CDSORTED (1<<0)
97
98/*
99 * TAKE NOTE:
100 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
101 */
102typedef struct zap_leaf_phys {
103	struct zap_leaf_header {
104		/* Public to ZAP */
105		uint64_t lh_block_type;		/* ZBT_LEAF */
106		uint64_t lh_pad1;
107		uint64_t lh_prefix;		/* hash prefix of this leaf */
108		uint32_t lh_magic;		/* ZAP_LEAF_MAGIC */
109		uint16_t lh_nfree;		/* number free chunks */
110		uint16_t lh_nentries;		/* number of entries */
111		uint16_t lh_prefix_len;		/* num bits used to id this */
112
113		/* Private to zap_leaf */
114		uint16_t lh_freelist;		/* chunk head of free list */
115		uint8_t lh_flags;		/* ZLF_* flags */
116		uint8_t lh_pad2[11];
117	} l_hdr; /* 2 24-byte chunks */
118
119	/*
120	 * The header is followed by a hash table with
121	 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
122	 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
123	 * zap_leaf_chunk structures.  These structures are accessed
124	 * with the ZAP_LEAF_CHUNK() macro.
125	 */
126
127	uint16_t l_hash[1];
128} zap_leaf_phys_t;
129
130typedef union zap_leaf_chunk {
131	struct zap_leaf_entry {
132		uint8_t le_type; 		/* always ZAP_CHUNK_ENTRY */
133		uint8_t le_value_intlen;	/* size of value's ints */
134		uint16_t le_next;		/* next entry in hash chain */
135		uint16_t le_name_chunk;		/* first chunk of the name */
136		uint16_t le_name_numints;	/* ints in name (incl null) */
137		uint16_t le_value_chunk;	/* first chunk of the value */
138		uint16_t le_value_numints;	/* value length in ints */
139		uint32_t le_cd;			/* collision differentiator */
140		uint64_t le_hash;		/* hash value of the name */
141	} l_entry;
142	struct zap_leaf_array {
143		uint8_t la_type;		/* always ZAP_CHUNK_ARRAY */
144		uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
145		uint16_t la_next;		/* next blk or CHAIN_END */
146	} l_array;
147	struct zap_leaf_free {
148		uint8_t lf_type;		/* always ZAP_CHUNK_FREE */
149		uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
150		uint16_t lf_next;	/* next in free list, or CHAIN_END */
151	} l_free;
152} zap_leaf_chunk_t;
153
154typedef struct zap_leaf {
155	krwlock_t l_rwlock;
156	uint64_t l_blkid;		/* 1<<ZAP_BLOCK_SHIFT byte block off */
157	int l_bs;			/* block size shift */
158	dmu_buf_t *l_dbuf;
159} zap_leaf_t;
160
161inline zap_leaf_phys_t *
162zap_leaf_phys(zap_leaf_t *l)
163{
164	return (l->l_dbuf->db_data);
165}
166
167typedef struct zap_entry_handle {
168	/* Set by zap_leaf and public to ZAP */
169	uint64_t zeh_num_integers;
170	uint64_t zeh_hash;
171	uint32_t zeh_cd;
172	uint8_t zeh_integer_size;
173
174	/* Private to zap_leaf */
175	uint16_t zeh_fakechunk;
176	uint16_t *zeh_chunkp;
177	zap_leaf_t *zeh_leaf;
178} zap_entry_handle_t;
179
180/*
181 * Return a handle to the named entry, or ENOENT if not found.  The hash
182 * value must equal zap_hash(name).
183 */
184extern int zap_leaf_lookup(zap_leaf_t *l,
185    struct zap_name *zn, zap_entry_handle_t *zeh);
186
187/*
188 * Return a handle to the entry with this hash+cd, or the entry with the
189 * next closest hash+cd.
190 */
191extern int zap_leaf_lookup_closest(zap_leaf_t *l,
192    uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
193
194/*
195 * Read the first num_integers in the attribute.  Integer size
196 * conversion will be done without sign extension.  Return EINVAL if
197 * integer_size is too small.  Return EOVERFLOW if there are more than
198 * num_integers in the attribute.
199 */
200extern int zap_entry_read(const zap_entry_handle_t *zeh,
201    uint8_t integer_size, uint64_t num_integers, void *buf);
202
203extern int zap_entry_read_name(struct zap *zap, const zap_entry_handle_t *zeh,
204    uint16_t buflen, char *buf);
205
206/*
207 * Replace the value of an existing entry.
208 *
209 * May fail if it runs out of space (ENOSPC).
210 */
211extern int zap_entry_update(zap_entry_handle_t *zeh,
212    uint8_t integer_size, uint64_t num_integers, const void *buf);
213
214/*
215 * Remove an entry.
216 */
217extern void zap_entry_remove(zap_entry_handle_t *zeh);
218
219/*
220 * Create an entry. An equal entry must not exist, and this entry must
221 * belong in this leaf (according to its hash value).  Fills in the
222 * entry handle on success.  Returns 0 on success or ENOSPC on failure.
223 */
224extern int zap_entry_create(zap_leaf_t *l, struct zap_name *zn, uint32_t cd,
225    uint8_t integer_size, uint64_t num_integers, const void *buf,
226    zap_entry_handle_t *zeh);
227
228/* Determine whether there is another entry with the same normalized form. */
229extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
230    struct zap_name *zn, const char *name, struct zap *zap);
231
232/*
233 * Other stuff.
234 */
235
236extern void zap_leaf_init(zap_leaf_t *l, boolean_t sort);
237extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
238extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort);
239extern void zap_leaf_stats(struct zap *zap, zap_leaf_t *l,
240    struct zap_stats *zs);
241
242#ifdef	__cplusplus
243}
244#endif
245
246#endif /* _SYS_ZAP_LEAF_H */
247