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Diffstat (limited to 'fs/ext4/ext4_extents.h')
-rw-r--r-- | fs/ext4/ext4_extents.h | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h new file mode 100644 index 000000000000..75333b595fab --- /dev/null +++ b/fs/ext4/ext4_extents.h | |||
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1 | /* | ||
2 | * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com | ||
3 | * Written by Alex Tomas <alex@clusterfs.com> | ||
4 | * | ||
5 | * This program is free software; you can redistribute it and/or modify | ||
6 | * it under the terms of the GNU General Public License version 2 as | ||
7 | * published by the Free Software Foundation. | ||
8 | * | ||
9 | * This program is distributed in the hope that it will be useful, | ||
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
12 | * GNU General Public License for more details. | ||
13 | * | ||
14 | * You should have received a copy of the GNU General Public Licens | ||
15 | * along with this program; if not, write to the Free Software | ||
16 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- | ||
17 | */ | ||
18 | |||
19 | #ifndef _EXT4_EXTENTS | ||
20 | #define _EXT4_EXTENTS | ||
21 | |||
22 | #include "ext4.h" | ||
23 | |||
24 | /* | ||
25 | * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks | ||
26 | * becomes very small, so index split, in-depth growing and | ||
27 | * other hard changes happen much more often. | ||
28 | * This is for debug purposes only. | ||
29 | */ | ||
30 | #define AGGRESSIVE_TEST_ | ||
31 | |||
32 | /* | ||
33 | * With EXTENTS_STATS defined, the number of blocks and extents | ||
34 | * are collected in the truncate path. They'll be shown at | ||
35 | * umount time. | ||
36 | */ | ||
37 | #define EXTENTS_STATS__ | ||
38 | |||
39 | /* | ||
40 | * If CHECK_BINSEARCH is defined, then the results of the binary search | ||
41 | * will also be checked by linear search. | ||
42 | */ | ||
43 | #define CHECK_BINSEARCH__ | ||
44 | |||
45 | /* | ||
46 | * If EXT_DEBUG is defined you can use the 'extdebug' mount option | ||
47 | * to get lots of info about what's going on. | ||
48 | */ | ||
49 | #define EXT_DEBUG__ | ||
50 | #ifdef EXT_DEBUG | ||
51 | #define ext_debug(a...) printk(a) | ||
52 | #else | ||
53 | #define ext_debug(a...) | ||
54 | #endif | ||
55 | |||
56 | /* | ||
57 | * If EXT_STATS is defined then stats numbers are collected. | ||
58 | * These number will be displayed at umount time. | ||
59 | */ | ||
60 | #define EXT_STATS_ | ||
61 | |||
62 | |||
63 | /* | ||
64 | * ext4_inode has i_block array (60 bytes total). | ||
65 | * The first 12 bytes store ext4_extent_header; | ||
66 | * the remainder stores an array of ext4_extent. | ||
67 | */ | ||
68 | |||
69 | /* | ||
70 | * This is the extent on-disk structure. | ||
71 | * It's used at the bottom of the tree. | ||
72 | */ | ||
73 | struct ext4_extent { | ||
74 | __le32 ee_block; /* first logical block extent covers */ | ||
75 | __le16 ee_len; /* number of blocks covered by extent */ | ||
76 | __le16 ee_start_hi; /* high 16 bits of physical block */ | ||
77 | __le32 ee_start_lo; /* low 32 bits of physical block */ | ||
78 | }; | ||
79 | |||
80 | /* | ||
81 | * This is index on-disk structure. | ||
82 | * It's used at all the levels except the bottom. | ||
83 | */ | ||
84 | struct ext4_extent_idx { | ||
85 | __le32 ei_block; /* index covers logical blocks from 'block' */ | ||
86 | __le32 ei_leaf_lo; /* pointer to the physical block of the next * | ||
87 | * level. leaf or next index could be there */ | ||
88 | __le16 ei_leaf_hi; /* high 16 bits of physical block */ | ||
89 | __u16 ei_unused; | ||
90 | }; | ||
91 | |||
92 | /* | ||
93 | * Each block (leaves and indexes), even inode-stored has header. | ||
94 | */ | ||
95 | struct ext4_extent_header { | ||
96 | __le16 eh_magic; /* probably will support different formats */ | ||
97 | __le16 eh_entries; /* number of valid entries */ | ||
98 | __le16 eh_max; /* capacity of store in entries */ | ||
99 | __le16 eh_depth; /* has tree real underlying blocks? */ | ||
100 | __le32 eh_generation; /* generation of the tree */ | ||
101 | }; | ||
102 | |||
103 | #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) | ||
104 | |||
105 | /* | ||
106 | * Array of ext4_ext_path contains path to some extent. | ||
107 | * Creation/lookup routines use it for traversal/splitting/etc. | ||
108 | * Truncate uses it to simulate recursive walking. | ||
109 | */ | ||
110 | struct ext4_ext_path { | ||
111 | ext4_fsblk_t p_block; | ||
112 | __u16 p_depth; | ||
113 | struct ext4_extent *p_ext; | ||
114 | struct ext4_extent_idx *p_idx; | ||
115 | struct ext4_extent_header *p_hdr; | ||
116 | struct buffer_head *p_bh; | ||
117 | }; | ||
118 | |||
119 | /* | ||
120 | * structure for external API | ||
121 | */ | ||
122 | |||
123 | #define EXT4_EXT_CACHE_NO 0 | ||
124 | #define EXT4_EXT_CACHE_GAP 1 | ||
125 | #define EXT4_EXT_CACHE_EXTENT 2 | ||
126 | |||
127 | |||
128 | #define EXT_MAX_BLOCK 0xffffffff | ||
129 | |||
130 | /* | ||
131 | * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an | ||
132 | * initialized extent. This is 2^15 and not (2^16 - 1), since we use the | ||
133 | * MSB of ee_len field in the extent datastructure to signify if this | ||
134 | * particular extent is an initialized extent or an uninitialized (i.e. | ||
135 | * preallocated). | ||
136 | * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an | ||
137 | * uninitialized extent. | ||
138 | * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an | ||
139 | * uninitialized one. In other words, if MSB of ee_len is set, it is an | ||
140 | * uninitialized extent with only one special scenario when ee_len = 0x8000. | ||
141 | * In this case we can not have an uninitialized extent of zero length and | ||
142 | * thus we make it as a special case of initialized extent with 0x8000 length. | ||
143 | * This way we get better extent-to-group alignment for initialized extents. | ||
144 | * Hence, the maximum number of blocks we can have in an *initialized* | ||
145 | * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767). | ||
146 | */ | ||
147 | #define EXT_INIT_MAX_LEN (1UL << 15) | ||
148 | #define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1) | ||
149 | |||
150 | |||
151 | #define EXT_FIRST_EXTENT(__hdr__) \ | ||
152 | ((struct ext4_extent *) (((char *) (__hdr__)) + \ | ||
153 | sizeof(struct ext4_extent_header))) | ||
154 | #define EXT_FIRST_INDEX(__hdr__) \ | ||
155 | ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ | ||
156 | sizeof(struct ext4_extent_header))) | ||
157 | #define EXT_HAS_FREE_INDEX(__path__) \ | ||
158 | (le16_to_cpu((__path__)->p_hdr->eh_entries) \ | ||
159 | < le16_to_cpu((__path__)->p_hdr->eh_max)) | ||
160 | #define EXT_LAST_EXTENT(__hdr__) \ | ||
161 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | ||
162 | #define EXT_LAST_INDEX(__hdr__) \ | ||
163 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | ||
164 | #define EXT_MAX_EXTENT(__hdr__) \ | ||
165 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | ||
166 | #define EXT_MAX_INDEX(__hdr__) \ | ||
167 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | ||
168 | |||
169 | static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) | ||
170 | { | ||
171 | return (struct ext4_extent_header *) EXT4_I(inode)->i_data; | ||
172 | } | ||
173 | |||
174 | static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) | ||
175 | { | ||
176 | return (struct ext4_extent_header *) bh->b_data; | ||
177 | } | ||
178 | |||
179 | static inline unsigned short ext_depth(struct inode *inode) | ||
180 | { | ||
181 | return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); | ||
182 | } | ||
183 | |||
184 | static inline void ext4_ext_tree_changed(struct inode *inode) | ||
185 | { | ||
186 | EXT4_I(inode)->i_ext_generation++; | ||
187 | } | ||
188 | |||
189 | static inline void | ||
190 | ext4_ext_invalidate_cache(struct inode *inode) | ||
191 | { | ||
192 | EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO; | ||
193 | } | ||
194 | |||
195 | static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext) | ||
196 | { | ||
197 | /* We can not have an uninitialized extent of zero length! */ | ||
198 | BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0); | ||
199 | ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN); | ||
200 | } | ||
201 | |||
202 | static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext) | ||
203 | { | ||
204 | /* Extent with ee_len of 0x8000 is treated as an initialized extent */ | ||
205 | return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN); | ||
206 | } | ||
207 | |||
208 | static inline int ext4_ext_get_actual_len(struct ext4_extent *ext) | ||
209 | { | ||
210 | return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ? | ||
211 | le16_to_cpu(ext->ee_len) : | ||
212 | (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN)); | ||
213 | } | ||
214 | |||
215 | extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *); | ||
216 | extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t); | ||
217 | extern int ext4_extent_tree_init(handle_t *, struct inode *); | ||
218 | extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *); | ||
219 | extern int ext4_ext_try_to_merge(struct inode *inode, | ||
220 | struct ext4_ext_path *path, | ||
221 | struct ext4_extent *); | ||
222 | extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *); | ||
223 | extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *); | ||
224 | extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t, | ||
225 | struct ext4_ext_path *); | ||
226 | extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *, | ||
227 | ext4_lblk_t *, ext4_fsblk_t *); | ||
228 | extern int ext4_ext_search_right(struct inode *, struct ext4_ext_path *, | ||
229 | ext4_lblk_t *, ext4_fsblk_t *); | ||
230 | extern void ext4_ext_drop_refs(struct ext4_ext_path *); | ||
231 | #endif /* _EXT4_EXTENTS */ | ||
232 | |||