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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 | * Turn on EXT_DEBUG to get lots of info about extents operations. |
47 | */ |
48 | #define EXT_DEBUG__ |
49 | #ifdef EXT_DEBUG |
50 | #define ext_debug(a...) printk(a) |
51 | #else |
52 | #define ext_debug(a...) |
53 | #endif |
54 | |
55 | /* |
56 | * If EXT_STATS is defined then stats numbers are collected. |
57 | * These number will be displayed at umount time. |
58 | */ |
59 | #define EXT_STATS_ |
60 | |
61 | |
62 | /* |
63 | * ext4_inode has i_block array (60 bytes total). |
64 | * The first 12 bytes store ext4_extent_header; |
65 | * the remainder stores an array of ext4_extent. |
66 | */ |
67 | |
68 | /* |
69 | * This is the extent on-disk structure. |
70 | * It's used at the bottom of the tree. |
71 | */ |
72 | struct ext4_extent { |
73 | __le32 ee_block; /* first logical block extent covers */ |
74 | __le16 ee_len; /* number of blocks covered by extent */ |
75 | __le16 ee_start_hi; /* high 16 bits of physical block */ |
76 | __le32 ee_start_lo; /* low 32 bits of physical block */ |
77 | }; |
78 | |
79 | /* |
80 | * This is index on-disk structure. |
81 | * It's used at all the levels except the bottom. |
82 | */ |
83 | struct ext4_extent_idx { |
84 | __le32 ei_block; /* index covers logical blocks from 'block' */ |
85 | __le32 ei_leaf_lo; /* pointer to the physical block of the next * |
86 | * level. leaf or next index could be there */ |
87 | __le16 ei_leaf_hi; /* high 16 bits of physical block */ |
88 | __u16 ei_unused; |
89 | }; |
90 | |
91 | /* |
92 | * Each block (leaves and indexes), even inode-stored has header. |
93 | */ |
94 | struct ext4_extent_header { |
95 | __le16 eh_magic; /* probably will support different formats */ |
96 | __le16 eh_entries; /* number of valid entries */ |
97 | __le16 eh_max; /* capacity of store in entries */ |
98 | __le16 eh_depth; /* has tree real underlying blocks? */ |
99 | __le32 eh_generation; /* generation of the tree */ |
100 | }; |
101 | |
102 | #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) |
103 | |
104 | /* |
105 | * Array of ext4_ext_path contains path to some extent. |
106 | * Creation/lookup routines use it for traversal/splitting/etc. |
107 | * Truncate uses it to simulate recursive walking. |
108 | */ |
109 | struct ext4_ext_path { |
110 | ext4_fsblk_t p_block; |
111 | __u16 p_depth; |
112 | struct ext4_extent *p_ext; |
113 | struct ext4_extent_idx *p_idx; |
114 | struct ext4_extent_header *p_hdr; |
115 | struct buffer_head *p_bh; |
116 | }; |
117 | |
118 | /* |
119 | * structure for external API |
120 | */ |
121 | |
122 | #define EXT4_EXT_CACHE_NO 0 |
123 | #define EXT4_EXT_CACHE_GAP 1 |
124 | #define EXT4_EXT_CACHE_EXTENT 2 |
125 | |
126 | /* |
127 | * to be called by ext4_ext_walk_space() |
128 | * negative retcode - error |
129 | * positive retcode - signal for ext4_ext_walk_space(), see below |
130 | * callback must return valid extent (passed or newly created) |
131 | */ |
132 | typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *, |
133 | struct ext4_ext_cache *, |
134 | struct ext4_extent *, void *); |
135 | |
136 | #define EXT_CONTINUE 0 |
137 | #define EXT_BREAK 1 |
138 | #define EXT_REPEAT 2 |
139 | |
140 | /* Maximum logical block in a file; ext4_extent's ee_block is __le32 */ |
141 | #define EXT_MAX_BLOCK 0xffffffff |
142 | |
143 | /* |
144 | * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an |
145 | * initialized extent. This is 2^15 and not (2^16 - 1), since we use the |
146 | * MSB of ee_len field in the extent datastructure to signify if this |
147 | * particular extent is an initialized extent or an uninitialized (i.e. |
148 | * preallocated). |
149 | * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an |
150 | * uninitialized extent. |
151 | * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an |
152 | * uninitialized one. In other words, if MSB of ee_len is set, it is an |
153 | * uninitialized extent with only one special scenario when ee_len = 0x8000. |
154 | * In this case we can not have an uninitialized extent of zero length and |
155 | * thus we make it as a special case of initialized extent with 0x8000 length. |
156 | * This way we get better extent-to-group alignment for initialized extents. |
157 | * Hence, the maximum number of blocks we can have in an *initialized* |
158 | * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767). |
159 | */ |
160 | #define EXT_INIT_MAX_LEN (1UL << 15) |
161 | #define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1) |
162 | |
163 | |
164 | #define EXT_FIRST_EXTENT(__hdr__) \ |
165 | ((struct ext4_extent *) (((char *) (__hdr__)) + \ |
166 | sizeof(struct ext4_extent_header))) |
167 | #define EXT_FIRST_INDEX(__hdr__) \ |
168 | ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ |
169 | sizeof(struct ext4_extent_header))) |
170 | #define EXT_HAS_FREE_INDEX(__path__) \ |
171 | (le16_to_cpu((__path__)->p_hdr->eh_entries) \ |
172 | < le16_to_cpu((__path__)->p_hdr->eh_max)) |
173 | #define EXT_LAST_EXTENT(__hdr__) \ |
174 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) |
175 | #define EXT_LAST_INDEX(__hdr__) \ |
176 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) |
177 | #define EXT_MAX_EXTENT(__hdr__) \ |
178 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) |
179 | #define EXT_MAX_INDEX(__hdr__) \ |
180 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) |
181 | |
182 | static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) |
183 | { |
184 | return (struct ext4_extent_header *) EXT4_I(inode)->i_data; |
185 | } |
186 | |
187 | static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) |
188 | { |
189 | return (struct ext4_extent_header *) bh->b_data; |
190 | } |
191 | |
192 | static inline unsigned short ext_depth(struct inode *inode) |
193 | { |
194 | return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); |
195 | } |
196 | |
197 | static inline void |
198 | ext4_ext_invalidate_cache(struct inode *inode) |
199 | { |
200 | EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO; |
201 | } |
202 | |
203 | static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext) |
204 | { |
205 | /* We can not have an uninitialized extent of zero length! */ |
206 | BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0); |
207 | ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN); |
208 | } |
209 | |
210 | static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext) |
211 | { |
212 | /* Extent with ee_len of 0x8000 is treated as an initialized extent */ |
213 | return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN); |
214 | } |
215 | |
216 | static inline int ext4_ext_get_actual_len(struct ext4_extent *ext) |
217 | { |
218 | return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ? |
219 | le16_to_cpu(ext->ee_len) : |
220 | (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN)); |
221 | } |
222 | |
223 | static inline void ext4_ext_mark_initialized(struct ext4_extent *ext) |
224 | { |
225 | ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext)); |
226 | } |
227 | |
228 | extern int ext4_ext_calc_metadata_amount(struct inode *inode, |
229 | sector_t lblocks); |
230 | extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex); |
231 | extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *); |
232 | extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t); |
233 | extern int ext4_extent_tree_init(handle_t *, struct inode *); |
234 | extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode, |
235 | int num, |
236 | struct ext4_ext_path *path); |
237 | extern int ext4_can_extents_be_merged(struct inode *inode, |
238 | struct ext4_extent *ex1, |
239 | struct ext4_extent *ex2); |
240 | extern int ext4_ext_try_to_merge(struct inode *inode, |
241 | struct ext4_ext_path *path, |
242 | struct ext4_extent *); |
243 | extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *); |
244 | extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int); |
245 | extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t, |
246 | ext_prepare_callback, void *); |
247 | extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t, |
248 | struct ext4_ext_path *); |
249 | extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *, |
250 | ext4_lblk_t *, ext4_fsblk_t *); |
251 | extern int ext4_ext_search_right(struct inode *, struct ext4_ext_path *, |
252 | ext4_lblk_t *, ext4_fsblk_t *); |
253 | extern void ext4_ext_drop_refs(struct ext4_ext_path *); |
254 | extern int ext4_ext_check_inode(struct inode *inode); |
255 | #endif /* _EXT4_EXTENTS */ |
256 | |
257 |
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