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a86c6181 AT |
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 _LINUX_EXT4_EXTENTS | |
20 | #define _LINUX_EXT4_EXTENTS | |
21 | ||
22 | #include <linux/ext4_fs.h> | |
23 | ||
24 | /* | |
bbf2f9fb | 25 | * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks |
d0d856e8 RD |
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. | |
a86c6181 | 29 | */ |
bbf2f9fb | 30 | #define AGGRESSIVE_TEST_ |
a86c6181 AT |
31 | |
32 | /* | |
d0d856e8 RD |
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. | |
a86c6181 AT |
36 | */ |
37 | #define EXTENTS_STATS__ | |
38 | ||
39 | /* | |
d0d856e8 RD |
40 | * If CHECK_BINSEARCH is defined, then the results of the binary search |
41 | * will also be checked by linear search. | |
a86c6181 AT |
42 | */ |
43 | #define CHECK_BINSEARCH__ | |
44 | ||
45 | /* | |
d0d856e8 RD |
46 | * If EXT_DEBUG is defined you can use the 'extdebug' mount option |
47 | * to get lots of info about what's going on. | |
a86c6181 AT |
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 | /* | |
d0d856e8 RD |
57 | * If EXT_STATS is defined then stats numbers are collected. |
58 | * These number will be displayed at umount time. | |
a86c6181 AT |
59 | */ |
60 | #define EXT_STATS_ | |
61 | ||
62 | ||
63 | /* | |
d0d856e8 RD |
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. | |
a86c6181 AT |
67 | */ |
68 | ||
69 | /* | |
d0d856e8 RD |
70 | * This is the extent on-disk structure. |
71 | * It's used at the bottom of the tree. | |
a86c6181 AT |
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 */ | |
d0d856e8 | 77 | __le32 ee_start; /* low 32 bits of physical block */ |
a86c6181 AT |
78 | }; |
79 | ||
80 | /* | |
d0d856e8 RD |
81 | * This is index on-disk structure. |
82 | * It's used at all the levels except the bottom. | |
a86c6181 AT |
83 | */ |
84 | struct ext4_extent_idx { | |
85 | __le32 ei_block; /* index covers logical blocks from 'block' */ | |
86 | __le32 ei_leaf; /* pointer to the physical block of the next * | |
d0d856e8 | 87 | * level. leaf or next index could be there */ |
a86c6181 AT |
88 | __le16 ei_leaf_hi; /* high 16 bits of physical block */ |
89 | __u16 ei_unused; | |
90 | }; | |
91 | ||
92 | /* | |
d0d856e8 | 93 | * Each block (leaves and indexes), even inode-stored has header. |
a86c6181 AT |
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 */ | |
d0d856e8 | 99 | __le16 eh_depth; /* has tree real underlying blocks? */ |
a86c6181 AT |
100 | __le32 eh_generation; /* generation of the tree */ |
101 | }; | |
102 | ||
103 | #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) | |
104 | ||
105 | /* | |
d0d856e8 RD |
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. | |
a86c6181 AT |
109 | */ |
110 | struct ext4_ext_path { | |
f65e6fba | 111 | ext4_fsblk_t p_block; |
a86c6181 AT |
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 | * to be called by ext4_ext_walk_space() | |
129 | * negative retcode - error | |
130 | * positive retcode - signal for ext4_ext_walk_space(), see below | |
131 | * callback must return valid extent (passed or newly created) | |
132 | */ | |
133 | typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *, | |
134 | struct ext4_ext_cache *, | |
135 | void *); | |
136 | ||
137 | #define EXT_CONTINUE 0 | |
138 | #define EXT_BREAK 1 | |
139 | #define EXT_REPEAT 2 | |
140 | ||
141 | ||
142 | #define EXT_MAX_BLOCK 0xffffffff | |
143 | ||
749269fa AA |
144 | /* |
145 | * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an | |
146 | * initialized extent. This is 2^15 and not (2^16 - 1), since we use the | |
147 | * MSB of ee_len field in the extent datastructure to signify if this | |
148 | * particular extent is an initialized extent or an uninitialized (i.e. | |
149 | * preallocated). | |
150 | * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an | |
151 | * uninitialized extent. | |
152 | * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an | |
153 | * uninitialized one. In other words, if MSB of ee_len is set, it is an | |
154 | * uninitialized extent with only one special scenario when ee_len = 0x8000. | |
155 | * In this case we can not have an uninitialized extent of zero length and | |
156 | * thus we make it as a special case of initialized extent with 0x8000 length. | |
157 | * This way we get better extent-to-group alignment for initialized extents. | |
158 | * Hence, the maximum number of blocks we can have in an *initialized* | |
159 | * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767). | |
160 | */ | |
161 | #define EXT_INIT_MAX_LEN (1UL << 15) | |
162 | #define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1) | |
471d4011 | 163 | |
a86c6181 AT |
164 | |
165 | #define EXT_FIRST_EXTENT(__hdr__) \ | |
166 | ((struct ext4_extent *) (((char *) (__hdr__)) + \ | |
167 | sizeof(struct ext4_extent_header))) | |
168 | #define EXT_FIRST_INDEX(__hdr__) \ | |
169 | ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ | |
170 | sizeof(struct ext4_extent_header))) | |
171 | #define EXT_HAS_FREE_INDEX(__path__) \ | |
8c55e204 DK |
172 | (le16_to_cpu((__path__)->p_hdr->eh_entries) \ |
173 | < le16_to_cpu((__path__)->p_hdr->eh_max)) | |
a86c6181 AT |
174 | #define EXT_LAST_EXTENT(__hdr__) \ |
175 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
176 | #define EXT_LAST_INDEX(__hdr__) \ | |
177 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
178 | #define EXT_MAX_EXTENT(__hdr__) \ | |
179 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
180 | #define EXT_MAX_INDEX(__hdr__) \ | |
181 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
182 | ||
183 | static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) | |
184 | { | |
185 | return (struct ext4_extent_header *) EXT4_I(inode)->i_data; | |
186 | } | |
187 | ||
188 | static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) | |
189 | { | |
190 | return (struct ext4_extent_header *) bh->b_data; | |
191 | } | |
192 | ||
193 | static inline unsigned short ext_depth(struct inode *inode) | |
194 | { | |
195 | return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); | |
196 | } | |
197 | ||
198 | static inline void ext4_ext_tree_changed(struct inode *inode) | |
199 | { | |
200 | EXT4_I(inode)->i_ext_generation++; | |
201 | } | |
202 | ||
203 | static inline void | |
204 | ext4_ext_invalidate_cache(struct inode *inode) | |
205 | { | |
206 | EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO; | |
207 | } | |
208 | ||
a2df2a63 AA |
209 | static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext) |
210 | { | |
749269fa AA |
211 | /* We can not have an uninitialized extent of zero length! */ |
212 | BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0); | |
213 | ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
214 | } |
215 | ||
216 | static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext) | |
217 | { | |
749269fa AA |
218 | /* Extent with ee_len of 0x8000 is treated as an initialized extent */ |
219 | return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
220 | } |
221 | ||
222 | static inline int ext4_ext_get_actual_len(struct ext4_extent *ext) | |
223 | { | |
749269fa AA |
224 | return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ? |
225 | le16_to_cpu(ext->ee_len) : | |
226 | (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN)); | |
a2df2a63 AA |
227 | } |
228 | ||
a86c6181 AT |
229 | extern int ext4_extent_tree_init(handle_t *, struct inode *); |
230 | extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *); | |
56055d3a AA |
231 | extern int ext4_ext_try_to_merge(struct inode *inode, |
232 | struct ext4_ext_path *path, | |
233 | struct ext4_extent *); | |
25d14f98 | 234 | extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *); |
a86c6181 AT |
235 | extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *); |
236 | extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *); | |
237 | extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *); | |
238 | ||
239 | #endif /* _LINUX_EXT4_EXTENTS */ | |
240 |