xref: /titanic_41/usr/src/uts/common/fs/zfs/sys/zap_leaf.h (revision 0521c5ebd0c906e1574175b64bd238405444c004)
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  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
24  */
25 
26 #ifndef	_SYS_ZAP_LEAF_H
27 #define	_SYS_ZAP_LEAF_H
28 
29 #include <sys/zap.h>
30 
31 #ifdef	__cplusplus
32 extern "C" {
33 #endif
34 
35 struct zap;
36 struct zap_name;
37 struct zap_stats;
38 
39 #define	ZAP_LEAF_MAGIC 0x2AB1EAF
40 
41 /* chunk size = 24 bytes */
42 #define	ZAP_LEAF_CHUNKSIZE 24
43 
44 /*
45  * The amount of space available for chunks is:
46  * block size (1<<l->l_bs) - hash entry size (2) * number of hash
47  * entries - header space (2*chunksize)
48  */
49 #define	ZAP_LEAF_NUMCHUNKS(l) \
50 	(((1<<(l)->l_bs) - 2*ZAP_LEAF_HASH_NUMENTRIES(l)) / \
51 	ZAP_LEAF_CHUNKSIZE - 2)
52 
53 /*
54  * The amount of space within the chunk available for the array is:
55  * chunk size - space for type (1) - space for next pointer (2)
56  */
57 #define	ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)
58 
59 #define	ZAP_LEAF_ARRAY_NCHUNKS(bytes) \
60 	(((bytes)+ZAP_LEAF_ARRAY_BYTES-1)/ZAP_LEAF_ARRAY_BYTES)
61 
62 /*
63  * Low water mark:  when there are only this many chunks free, start
64  * growing the ptrtbl.  Ideally, this should be larger than a
65  * "reasonably-sized" entry.  20 chunks is more than enough for the
66  * largest directory entry (MAXNAMELEN (256) byte name, 8-byte value),
67  * while still being only around 3% for 16k blocks.
68  */
69 #define	ZAP_LEAF_LOW_WATER (20)
70 
71 /*
72  * The leaf hash table has block size / 2^5 (32) number of entries,
73  * which should be more than enough for the maximum number of entries,
74  * which is less than block size / CHUNKSIZE (24) / minimum number of
75  * chunks per entry (3).
76  */
77 #define	ZAP_LEAF_HASH_SHIFT(l) ((l)->l_bs - 5)
78 #define	ZAP_LEAF_HASH_NUMENTRIES(l) (1 << ZAP_LEAF_HASH_SHIFT(l))
79 
80 /*
81  * The chunks start immediately after the hash table.  The end of the
82  * hash table is at l_hash + HASH_NUMENTRIES, which we simply cast to a
83  * chunk_t.
84  */
85 #define	ZAP_LEAF_CHUNK(l, idx) \
86 	((zap_leaf_chunk_t *) \
87 	(zap_leaf_phys(l)->l_hash + ZAP_LEAF_HASH_NUMENTRIES(l)))[idx]
88 #define	ZAP_LEAF_ENTRY(l, idx) (&ZAP_LEAF_CHUNK(l, idx).l_entry)
89 
90 typedef enum zap_chunk_type {
91 	ZAP_CHUNK_FREE = 253,
92 	ZAP_CHUNK_ENTRY = 252,
93 	ZAP_CHUNK_ARRAY = 251,
94 	ZAP_CHUNK_TYPE_MAX = 250
95 } zap_chunk_type_t;
96 
97 #define	ZLF_ENTRIES_CDSORTED (1<<0)
98 
99 /*
100  * TAKE NOTE:
101  * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
102  */
103 typedef struct zap_leaf_phys {
104 	struct zap_leaf_header {
105 		/* Public to ZAP */
106 		uint64_t lh_block_type;		/* ZBT_LEAF */
107 		uint64_t lh_pad1;
108 		uint64_t lh_prefix;		/* hash prefix of this leaf */
109 		uint32_t lh_magic;		/* ZAP_LEAF_MAGIC */
110 		uint16_t lh_nfree;		/* number free chunks */
111 		uint16_t lh_nentries;		/* number of entries */
112 		uint16_t lh_prefix_len;		/* num bits used to id this */
113 
114 		/* Private to zap_leaf */
115 		uint16_t lh_freelist;		/* chunk head of free list */
116 		uint8_t lh_flags;		/* ZLF_* flags */
117 		uint8_t lh_pad2[11];
118 	} l_hdr; /* 2 24-byte chunks */
119 
120 	/*
121 	 * The header is followed by a hash table with
122 	 * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
123 	 * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
124 	 * zap_leaf_chunk structures.  These structures are accessed
125 	 * with the ZAP_LEAF_CHUNK() macro.
126 	 */
127 
128 	uint16_t l_hash[1];
129 } zap_leaf_phys_t;
130 
131 typedef union zap_leaf_chunk {
132 	struct zap_leaf_entry {
133 		uint8_t le_type; 		/* always ZAP_CHUNK_ENTRY */
134 		uint8_t le_value_intlen;	/* size of value's ints */
135 		uint16_t le_next;		/* next entry in hash chain */
136 		uint16_t le_name_chunk;		/* first chunk of the name */
137 		uint16_t le_name_numints;	/* ints in name (incl null) */
138 		uint16_t le_value_chunk;	/* first chunk of the value */
139 		uint16_t le_value_numints;	/* value length in ints */
140 		uint32_t le_cd;			/* collision differentiator */
141 		uint64_t le_hash;		/* hash value of the name */
142 	} l_entry;
143 	struct zap_leaf_array {
144 		uint8_t la_type;		/* always ZAP_CHUNK_ARRAY */
145 		uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
146 		uint16_t la_next;		/* next blk or CHAIN_END */
147 	} l_array;
148 	struct zap_leaf_free {
149 		uint8_t lf_type;		/* always ZAP_CHUNK_FREE */
150 		uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
151 		uint16_t lf_next;	/* next in free list, or CHAIN_END */
152 	} l_free;
153 } zap_leaf_chunk_t;
154 
155 typedef struct zap_leaf {
156 	dmu_buf_user_t l_dbu;
157 	krwlock_t l_rwlock;
158 	uint64_t l_blkid;		/* 1<<ZAP_BLOCK_SHIFT byte block off */
159 	int l_bs;			/* block size shift */
160 	dmu_buf_t *l_dbuf;
161 } zap_leaf_t;
162 
163 inline zap_leaf_phys_t *
zap_leaf_phys(zap_leaf_t * l)164 zap_leaf_phys(zap_leaf_t *l)
165 {
166 	return (l->l_dbuf->db_data);
167 }
168 
169 typedef struct zap_entry_handle {
170 	/* Set by zap_leaf and public to ZAP */
171 	uint64_t zeh_num_integers;
172 	uint64_t zeh_hash;
173 	uint32_t zeh_cd;
174 	uint8_t zeh_integer_size;
175 
176 	/* Private to zap_leaf */
177 	uint16_t zeh_fakechunk;
178 	uint16_t *zeh_chunkp;
179 	zap_leaf_t *zeh_leaf;
180 } zap_entry_handle_t;
181 
182 /*
183  * Return a handle to the named entry, or ENOENT if not found.  The hash
184  * value must equal zap_hash(name).
185  */
186 extern int zap_leaf_lookup(zap_leaf_t *l,
187     struct zap_name *zn, zap_entry_handle_t *zeh);
188 
189 /*
190  * Return a handle to the entry with this hash+cd, or the entry with the
191  * next closest hash+cd.
192  */
193 extern int zap_leaf_lookup_closest(zap_leaf_t *l,
194     uint64_t hash, uint32_t cd, zap_entry_handle_t *zeh);
195 
196 /*
197  * Read the first num_integers in the attribute.  Integer size
198  * conversion will be done without sign extension.  Return EINVAL if
199  * integer_size is too small.  Return EOVERFLOW if there are more than
200  * num_integers in the attribute.
201  */
202 extern int zap_entry_read(const zap_entry_handle_t *zeh,
203     uint8_t integer_size, uint64_t num_integers, void *buf);
204 
205 extern int zap_entry_read_name(struct zap *zap, const zap_entry_handle_t *zeh,
206     uint16_t buflen, char *buf);
207 
208 /*
209  * Replace the value of an existing entry.
210  *
211  * May fail if it runs out of space (ENOSPC).
212  */
213 extern int zap_entry_update(zap_entry_handle_t *zeh,
214     uint8_t integer_size, uint64_t num_integers, const void *buf);
215 
216 /*
217  * Remove an entry.
218  */
219 extern void zap_entry_remove(zap_entry_handle_t *zeh);
220 
221 /*
222  * Create an entry. An equal entry must not exist, and this entry must
223  * belong in this leaf (according to its hash value).  Fills in the
224  * entry handle on success.  Returns 0 on success or ENOSPC on failure.
225  */
226 extern int zap_entry_create(zap_leaf_t *l, struct zap_name *zn, uint32_t cd,
227     uint8_t integer_size, uint64_t num_integers, const void *buf,
228     zap_entry_handle_t *zeh);
229 
230 /* Determine whether there is another entry with the same normalized form. */
231 extern boolean_t zap_entry_normalization_conflict(zap_entry_handle_t *zeh,
232     struct zap_name *zn, const char *name, struct zap *zap);
233 
234 /*
235  * Other stuff.
236  */
237 
238 extern void zap_leaf_init(zap_leaf_t *l, boolean_t sort);
239 extern void zap_leaf_byteswap(zap_leaf_phys_t *buf, int len);
240 extern void zap_leaf_split(zap_leaf_t *l, zap_leaf_t *nl, boolean_t sort);
241 extern void zap_leaf_stats(struct zap *zap, zap_leaf_t *l,
242     struct zap_stats *zs);
243 
244 #ifdef	__cplusplus
245 }
246 #endif
247 
248 #endif /* _SYS_ZAP_LEAF_H */
249