Commit | Line | Data |
---|---|---|
f5166768 | 1 | // SPDX-License-Identifier: GPL-2.0 |
a86c6181 AT |
2 | /* |
3 | * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com | |
4 | * Written by Alex Tomas <alex@clusterfs.com> | |
a86c6181 AT |
5 | */ |
6 | ||
3dcf5451 CH |
7 | #ifndef _EXT4_EXTENTS |
8 | #define _EXT4_EXTENTS | |
a86c6181 | 9 | |
3dcf5451 | 10 | #include "ext4.h" |
a86c6181 AT |
11 | |
12 | /* | |
bbf2f9fb | 13 | * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks |
d0d856e8 RD |
14 | * becomes very small, so index split, in-depth growing and |
15 | * other hard changes happen much more often. | |
16 | * This is for debug purposes only. | |
a86c6181 | 17 | */ |
bbf2f9fb | 18 | #define AGGRESSIVE_TEST_ |
a86c6181 AT |
19 | |
20 | /* | |
d0d856e8 RD |
21 | * With EXTENTS_STATS defined, the number of blocks and extents |
22 | * are collected in the truncate path. They'll be shown at | |
23 | * umount time. | |
a86c6181 AT |
24 | */ |
25 | #define EXTENTS_STATS__ | |
26 | ||
27 | /* | |
d0d856e8 RD |
28 | * If CHECK_BINSEARCH is defined, then the results of the binary search |
29 | * will also be checked by linear search. | |
a86c6181 AT |
30 | */ |
31 | #define CHECK_BINSEARCH__ | |
32 | ||
a86c6181 | 33 | /* |
d0d856e8 RD |
34 | * If EXT_STATS is defined then stats numbers are collected. |
35 | * These number will be displayed at umount time. | |
a86c6181 AT |
36 | */ |
37 | #define EXT_STATS_ | |
38 | ||
39 | ||
40 | /* | |
d0d856e8 RD |
41 | * ext4_inode has i_block array (60 bytes total). |
42 | * The first 12 bytes store ext4_extent_header; | |
43 | * the remainder stores an array of ext4_extent. | |
e6153918 DW |
44 | * For non-inode extent blocks, ext4_extent_tail |
45 | * follows the array. | |
a86c6181 AT |
46 | */ |
47 | ||
e6153918 DW |
48 | /* |
49 | * This is the extent tail on-disk structure. | |
50 | * All other extent structures are 12 bytes long. It turns out that | |
51 | * block_size % 12 >= 4 for at least all powers of 2 greater than 512, which | |
52 | * covers all valid ext4 block sizes. Therefore, this tail structure can be | |
53 | * crammed into the end of the block without having to rebalance the tree. | |
54 | */ | |
55 | struct ext4_extent_tail { | |
56 | __le32 et_checksum; /* crc32c(uuid+inum+extent_block) */ | |
57 | }; | |
58 | ||
a86c6181 | 59 | /* |
d0d856e8 RD |
60 | * This is the extent on-disk structure. |
61 | * It's used at the bottom of the tree. | |
a86c6181 AT |
62 | */ |
63 | struct ext4_extent { | |
64 | __le32 ee_block; /* first logical block extent covers */ | |
65 | __le16 ee_len; /* number of blocks covered by extent */ | |
66 | __le16 ee_start_hi; /* high 16 bits of physical block */ | |
b377611d | 67 | __le32 ee_start_lo; /* low 32 bits of physical block */ |
a86c6181 AT |
68 | }; |
69 | ||
70 | /* | |
d0d856e8 RD |
71 | * This is index on-disk structure. |
72 | * It's used at all the levels except the bottom. | |
a86c6181 AT |
73 | */ |
74 | struct ext4_extent_idx { | |
75 | __le32 ei_block; /* index covers logical blocks from 'block' */ | |
d8dd0b45 | 76 | __le32 ei_leaf_lo; /* pointer to the physical block of the next * |
d0d856e8 | 77 | * level. leaf or next index could be there */ |
a86c6181 AT |
78 | __le16 ei_leaf_hi; /* high 16 bits of physical block */ |
79 | __u16 ei_unused; | |
80 | }; | |
81 | ||
82 | /* | |
d0d856e8 | 83 | * Each block (leaves and indexes), even inode-stored has header. |
a86c6181 AT |
84 | */ |
85 | struct ext4_extent_header { | |
86 | __le16 eh_magic; /* probably will support different formats */ | |
87 | __le16 eh_entries; /* number of valid entries */ | |
88 | __le16 eh_max; /* capacity of store in entries */ | |
d0d856e8 | 89 | __le16 eh_depth; /* has tree real underlying blocks? */ |
a86c6181 AT |
90 | __le32 eh_generation; /* generation of the tree */ |
91 | }; | |
92 | ||
93 | #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) | |
94 | ||
7ac5990d DW |
95 | #define EXT4_EXTENT_TAIL_OFFSET(hdr) \ |
96 | (sizeof(struct ext4_extent_header) + \ | |
97 | (sizeof(struct ext4_extent) * le16_to_cpu((hdr)->eh_max))) | |
98 | ||
99 | static inline struct ext4_extent_tail * | |
100 | find_ext4_extent_tail(struct ext4_extent_header *eh) | |
101 | { | |
102 | return (struct ext4_extent_tail *)(((void *)eh) + | |
103 | EXT4_EXTENT_TAIL_OFFSET(eh)); | |
104 | } | |
105 | ||
a86c6181 | 106 | /* |
d0d856e8 RD |
107 | * Array of ext4_ext_path contains path to some extent. |
108 | * Creation/lookup routines use it for traversal/splitting/etc. | |
109 | * Truncate uses it to simulate recursive walking. | |
a86c6181 AT |
110 | */ |
111 | struct ext4_ext_path { | |
f65e6fba | 112 | ext4_fsblk_t p_block; |
a86c6181 | 113 | __u16 p_depth; |
10809df8 | 114 | __u16 p_maxdepth; |
a86c6181 AT |
115 | struct ext4_extent *p_ext; |
116 | struct ext4_extent_idx *p_idx; | |
117 | struct ext4_extent_header *p_hdr; | |
118 | struct buffer_head *p_bh; | |
119 | }; | |
120 | ||
121 | /* | |
122 | * structure for external API | |
123 | */ | |
124 | ||
749269fa AA |
125 | /* |
126 | * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an | |
127 | * initialized extent. This is 2^15 and not (2^16 - 1), since we use the | |
128 | * MSB of ee_len field in the extent datastructure to signify if this | |
556615dc | 129 | * particular extent is an initialized extent or an unwritten (i.e. |
749269fa | 130 | * preallocated). |
556615dc LC |
131 | * EXT_UNWRITTEN_MAX_LEN is the maximum number of blocks we can have in an |
132 | * unwritten extent. | |
749269fa | 133 | * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an |
556615dc LC |
134 | * unwritten one. In other words, if MSB of ee_len is set, it is an |
135 | * unwritten extent with only one special scenario when ee_len = 0x8000. | |
136 | * In this case we can not have an unwritten extent of zero length and | |
749269fa AA |
137 | * thus we make it as a special case of initialized extent with 0x8000 length. |
138 | * This way we get better extent-to-group alignment for initialized extents. | |
139 | * Hence, the maximum number of blocks we can have in an *initialized* | |
556615dc | 140 | * extent is 2^15 (32768) and in an *unwritten* extent is 2^15-1 (32767). |
749269fa AA |
141 | */ |
142 | #define EXT_INIT_MAX_LEN (1UL << 15) | |
556615dc | 143 | #define EXT_UNWRITTEN_MAX_LEN (EXT_INIT_MAX_LEN - 1) |
471d4011 | 144 | |
a86c6181 AT |
145 | |
146 | #define EXT_FIRST_EXTENT(__hdr__) \ | |
147 | ((struct ext4_extent *) (((char *) (__hdr__)) + \ | |
148 | sizeof(struct ext4_extent_header))) | |
149 | #define EXT_FIRST_INDEX(__hdr__) \ | |
150 | ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ | |
151 | sizeof(struct ext4_extent_header))) | |
152 | #define EXT_HAS_FREE_INDEX(__path__) \ | |
8c55e204 DK |
153 | (le16_to_cpu((__path__)->p_hdr->eh_entries) \ |
154 | < le16_to_cpu((__path__)->p_hdr->eh_max)) | |
a86c6181 AT |
155 | #define EXT_LAST_EXTENT(__hdr__) \ |
156 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
157 | #define EXT_LAST_INDEX(__hdr__) \ | |
158 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
159 | #define EXT_MAX_EXTENT(__hdr__) \ | |
160 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
161 | #define EXT_MAX_INDEX(__hdr__) \ | |
162 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
163 | ||
164 | static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) | |
165 | { | |
166 | return (struct ext4_extent_header *) EXT4_I(inode)->i_data; | |
167 | } | |
168 | ||
169 | static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) | |
170 | { | |
171 | return (struct ext4_extent_header *) bh->b_data; | |
172 | } | |
173 | ||
174 | static inline unsigned short ext_depth(struct inode *inode) | |
175 | { | |
176 | return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); | |
177 | } | |
178 | ||
556615dc | 179 | static inline void ext4_ext_mark_unwritten(struct ext4_extent *ext) |
a2df2a63 | 180 | { |
556615dc | 181 | /* We can not have an unwritten extent of zero length! */ |
749269fa AA |
182 | BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0); |
183 | ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
184 | } |
185 | ||
556615dc | 186 | static inline int ext4_ext_is_unwritten(struct ext4_extent *ext) |
a2df2a63 | 187 | { |
749269fa AA |
188 | /* Extent with ee_len of 0x8000 is treated as an initialized extent */ |
189 | return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
190 | } |
191 | ||
192 | static inline int ext4_ext_get_actual_len(struct ext4_extent *ext) | |
193 | { | |
749269fa AA |
194 | return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ? |
195 | le16_to_cpu(ext->ee_len) : | |
196 | (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN)); | |
a2df2a63 AA |
197 | } |
198 | ||
0031462b MC |
199 | static inline void ext4_ext_mark_initialized(struct ext4_extent *ext) |
200 | { | |
201 | ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext)); | |
202 | } | |
203 | ||
bf89d16f TT |
204 | /* |
205 | * ext4_ext_pblock: | |
206 | * combine low and high parts of physical block number into ext4_fsblk_t | |
207 | */ | |
208 | static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex) | |
209 | { | |
210 | ext4_fsblk_t block; | |
211 | ||
212 | block = le32_to_cpu(ex->ee_start_lo); | |
213 | block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; | |
214 | return block; | |
215 | } | |
216 | ||
217 | /* | |
218 | * ext4_idx_pblock: | |
219 | * combine low and high parts of a leaf physical block number into ext4_fsblk_t | |
220 | */ | |
221 | static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix) | |
222 | { | |
223 | ext4_fsblk_t block; | |
224 | ||
225 | block = le32_to_cpu(ix->ei_leaf_lo); | |
226 | block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; | |
227 | return block; | |
228 | } | |
229 | ||
230 | /* | |
231 | * ext4_ext_store_pblock: | |
232 | * stores a large physical block number into an extent struct, | |
233 | * breaking it into parts | |
234 | */ | |
235 | static inline void ext4_ext_store_pblock(struct ext4_extent *ex, | |
236 | ext4_fsblk_t pb) | |
237 | { | |
238 | ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); | |
239 | ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & | |
240 | 0xffff); | |
241 | } | |
242 | ||
243 | /* | |
244 | * ext4_idx_store_pblock: | |
245 | * stores a large physical block number into an index struct, | |
246 | * breaking it into parts | |
247 | */ | |
248 | static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix, | |
249 | ext4_fsblk_t pb) | |
250 | { | |
251 | ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); | |
252 | ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & | |
253 | 0xffff); | |
254 | } | |
255 | ||
2656497b DW |
256 | #define ext4_ext_dirty(handle, inode, path) \ |
257 | __ext4_ext_dirty(__func__, __LINE__, (handle), (inode), (path)) | |
258 | int __ext4_ext_dirty(const char *where, unsigned int line, handle_t *handle, | |
259 | struct inode *inode, struct ext4_ext_path *path); | |
260 | ||
3dcf5451 | 261 | #endif /* _EXT4_EXTENTS */ |
a86c6181 | 262 |