1 // SPDX-License-Identifier: GPL-2.0 1
2 /*
3 * Copyright (c) 2003-2006, Cluster File Syste
4 * Written by Alex Tomas <alex@clusterfs.com>
5 */
6
7 #ifndef _EXT4_EXTENTS
8 #define _EXT4_EXTENTS
9
10 #include "ext4.h"
11
12 /*
13 * With AGGRESSIVE_TEST defined, the capacity
14 * becomes very small, so index split, in-dept
15 * other hard changes happen much more often.
16 * This is for debug purposes only.
17 */
18 #define AGGRESSIVE_TEST_
19
20 /*
21 * With EXTENTS_STATS defined, the number of b
22 * are collected in the truncate path. They'll
23 * umount time.
24 */
25 #define EXTENTS_STATS__
26
27 /*
28 * If CHECK_BINSEARCH is defined, then the res
29 * will also be checked by linear search.
30 */
31 #define CHECK_BINSEARCH__
32
33 /*
34 * If EXT_STATS is defined then stats numbers
35 * These number will be displayed at umount ti
36 */
37 #define EXT_STATS_
38
39
40 /*
41 * ext4_inode has i_block array (60 bytes tota
42 * The first 12 bytes store ext4_extent_header
43 * the remainder stores an array of ext4_exten
44 * For non-inode extent blocks, ext4_extent_ta
45 * follows the array.
46 */
47
48 /*
49 * This is the extent tail on-disk structure.
50 * All other extent structures are 12 bytes lo
51 * block_size % 12 >= 4 for at least all power
52 * covers all valid ext4 block sizes. Therefo
53 * crammed into the end of the block without h
54 */
55 struct ext4_extent_tail {
56 __le32 et_checksum; /* crc32c(uuid
57 };
58
59 /*
60 * This is the extent on-disk structure.
61 * It's used at the bottom of the tree.
62 */
63 struct ext4_extent {
64 __le32 ee_block; /* first logic
65 __le16 ee_len; /* number of b
66 __le16 ee_start_hi; /* high 16 bit
67 __le32 ee_start_lo; /* low 32 bits
68 };
69
70 /*
71 * This is index on-disk structure.
72 * It's used at all the levels except the bott
73 */
74 struct ext4_extent_idx {
75 __le32 ei_block; /* index cover
76 __le32 ei_leaf_lo; /* pointer to
77 * level. leaf
78 __le16 ei_leaf_hi; /* high 16 bit
79 __u16 ei_unused;
80 };
81
82 /*
83 * Each block (leaves and indexes), even inode
84 */
85 struct ext4_extent_header {
86 __le16 eh_magic; /* probably wi
87 __le16 eh_entries; /* number of v
88 __le16 eh_max; /* capacity of
89 __le16 eh_depth; /* has tree re
90 __le32 eh_generation; /* generation
91 };
92
93 #define EXT4_EXT_MAGIC cpu_to_le16(0x
94 #define EXT4_MAX_EXTENT_DEPTH 5
95
96 #define EXT4_EXTENT_TAIL_OFFSET(hdr) \
97 (sizeof(struct ext4_extent_header) + \
98 (sizeof(struct ext4_extent) * le16_to
99
100 static inline struct ext4_extent_tail *
101 find_ext4_extent_tail(struct ext4_extent_heade
102 {
103 return (struct ext4_extent_tail *)(((v
104 EXT
105 }
106
107 /*
108 * Array of ext4_ext_path contains path to som
109 * Creation/lookup routines use it for travers
110 * Truncate uses it to simulate recursive walk
111 */
112 struct ext4_ext_path {
113 ext4_fsblk_t p_bloc
114 __u16 p_dept
115 __u16 p_maxd
116 struct ext4_extent *p_ext
117 struct ext4_extent_idx *p_idx
118 struct ext4_extent_header *p_hdr
119 struct buffer_head *p_bh;
120 };
121
122 /*
123 * Used to record a portion of a cluster found
124 * of an extent while traversing the extent tr
125 * A partial cluster may be removed if it does
126 * with extents that aren't being deleted (tof
127 * it cannot be removed (nofree state).
128 */
129 struct partial_cluster {
130 ext4_fsblk_t pclu; /* physical cluste
131 ext4_lblk_t lblk; /* logical block n
132 enum {initial, tofree, nofree} state;
133 };
134
135 /*
136 * structure for external API
137 */
138
139 /*
140 * EXT_INIT_MAX_LEN is the maximum number of b
141 * initialized extent. This is 2^15 and not (2
142 * MSB of ee_len field in the extent datastruc
143 * particular extent is an initialized extent
144 * preallocated).
145 * EXT_UNWRITTEN_MAX_LEN is the maximum number
146 * unwritten extent.
147 * If ee_len is <= 0x8000, it is an initialize
148 * unwritten one. In other words, if MSB of ee
149 * unwritten extent with only one special scen
150 * In this case we can not have an unwritten e
151 * thus we make it as a special case of initia
152 * This way we get better extent-to-group alig
153 * Hence, the maximum number of blocks we can
154 * extent is 2^15 (32768) and in an *unwritten
155 */
156 #define EXT_INIT_MAX_LEN (1UL << 15)
157 #define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_
158
159
160 #define EXT_FIRST_EXTENT(__hdr__) \
161 ((struct ext4_extent *) (((char *) (__
162 sizeof(struct
163 #define EXT_FIRST_INDEX(__hdr__) \
164 ((struct ext4_extent_idx *) (((char *)
165 sizeof(st
166 #define EXT_HAS_FREE_INDEX(__path__) \
167 (le16_to_cpu((__path__)->p_hdr->eh_ent
168 < le16_to
169 #define EXT_LAST_EXTENT(__hdr__) \
170 (EXT_FIRST_EXTENT((__hdr__)) + le16_to
171 #define EXT_LAST_INDEX(__hdr__) \
172 (EXT_FIRST_INDEX((__hdr__)) + le16_to_
173 #define EXT_MAX_EXTENT(__hdr__) \
174 ((le16_to_cpu((__hdr__)->eh_max)) ? \
175 ((EXT_FIRST_EXTENT((__hdr__)) + le16_t
176 : NULL
177 #define EXT_MAX_INDEX(__hdr__) \
178 ((le16_to_cpu((__hdr__)->eh_max)) ? \
179 ((EXT_FIRST_INDEX((__hdr__)) + le16_to
180 : NULL
181
182 static inline struct ext4_extent_header *ext_i
183 {
184 return (struct ext4_extent_header *) E
185 }
186
187 static inline struct ext4_extent_header *ext_b
188 {
189 return (struct ext4_extent_header *) b
190 }
191
192 static inline unsigned short ext_depth(struct
193 {
194 return le16_to_cpu(ext_inode_hdr(inode
195 }
196
197 static inline void ext4_ext_mark_unwritten(str
198 {
199 /* We can not have an unwritten extent
200 BUG_ON((le16_to_cpu(ext->ee_len) & ~EX
201 ext->ee_len |= cpu_to_le16(EXT_INIT_MA
202 }
203
204 static inline int ext4_ext_is_unwritten(struct
205 {
206 /* Extent with ee_len of 0x8000 is tre
207 return (le16_to_cpu(ext->ee_len) > EXT
208 }
209
210 static inline int ext4_ext_get_actual_len(stru
211 {
212 return (le16_to_cpu(ext->ee_len) <= EX
213 le16_to_cpu(ext->ee_len) :
214 (le16_to_cpu(ext->ee_len) - EX
215 }
216
217 static inline void ext4_ext_mark_initialized(s
218 {
219 ext->ee_len = cpu_to_le16(ext4_ext_get
220 }
221
222 /*
223 * ext4_ext_pblock:
224 * combine low and high parts of physical bloc
225 */
226 static inline ext4_fsblk_t ext4_ext_pblock(str
227 {
228 ext4_fsblk_t block;
229
230 block = le32_to_cpu(ex->ee_start_lo);
231 block |= ((ext4_fsblk_t) le16_to_cpu(e
232 return block;
233 }
234
235 /*
236 * ext4_idx_pblock:
237 * combine low and high parts of a leaf physic
238 */
239 static inline ext4_fsblk_t ext4_idx_pblock(str
240 {
241 ext4_fsblk_t block;
242
243 block = le32_to_cpu(ix->ei_leaf_lo);
244 block |= ((ext4_fsblk_t) le16_to_cpu(i
245 return block;
246 }
247
248 /*
249 * ext4_ext_store_pblock:
250 * stores a large physical block number into a
251 * breaking it into parts
252 */
253 static inline void ext4_ext_store_pblock(struc
254 ext4_
255 {
256 ex->ee_start_lo = cpu_to_le32((unsigne
257 ex->ee_start_hi = cpu_to_le16((unsigne
258 0xffff);
259 }
260
261 /*
262 * ext4_idx_store_pblock:
263 * stores a large physical block number into a
264 * breaking it into parts
265 */
266 static inline void ext4_idx_store_pblock(struc
267 ext4_
268 {
269 ix->ei_leaf_lo = cpu_to_le32((unsigned
270 ix->ei_leaf_hi = cpu_to_le16((unsigned
271 0xffff);
272 }
273
274 #endif /* _EXT4_EXTENTS */
275
276
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