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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 | ||
3dcf5451 CH |
19 | #ifndef _EXT4_EXTENTS |
20 | #define _EXT4_EXTENTS | |
a86c6181 | 21 | |
3dcf5451 | 22 | #include "ext4.h" |
a86c6181 AT |
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 | /* | |
553f9008 | 46 | * Turn on EXT_DEBUG to get lots of info about extents operations. |
a86c6181 AT |
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 | /* | |
d0d856e8 RD |
56 | * If EXT_STATS is defined then stats numbers are collected. |
57 | * These number will be displayed at umount time. | |
a86c6181 AT |
58 | */ |
59 | #define EXT_STATS_ | |
60 | ||
61 | ||
62 | /* | |
d0d856e8 RD |
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. | |
a86c6181 AT |
66 | */ |
67 | ||
68 | /* | |
d0d856e8 RD |
69 | * This is the extent on-disk structure. |
70 | * It's used at the bottom of the tree. | |
a86c6181 AT |
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 */ | |
b377611d | 76 | __le32 ee_start_lo; /* low 32 bits of physical block */ |
a86c6181 AT |
77 | }; |
78 | ||
79 | /* | |
d0d856e8 RD |
80 | * This is index on-disk structure. |
81 | * It's used at all the levels except the bottom. | |
a86c6181 AT |
82 | */ |
83 | struct ext4_extent_idx { | |
84 | __le32 ei_block; /* index covers logical blocks from 'block' */ | |
d8dd0b45 | 85 | __le32 ei_leaf_lo; /* pointer to the physical block of the next * |
d0d856e8 | 86 | * level. leaf or next index could be there */ |
a86c6181 AT |
87 | __le16 ei_leaf_hi; /* high 16 bits of physical block */ |
88 | __u16 ei_unused; | |
89 | }; | |
90 | ||
91 | /* | |
d0d856e8 | 92 | * Each block (leaves and indexes), even inode-stored has header. |
a86c6181 AT |
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 */ | |
d0d856e8 | 98 | __le16 eh_depth; /* has tree real underlying blocks? */ |
a86c6181 AT |
99 | __le32 eh_generation; /* generation of the tree */ |
100 | }; | |
101 | ||
102 | #define EXT4_EXT_MAGIC cpu_to_le16(0xf30a) | |
103 | ||
104 | /* | |
d0d856e8 RD |
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. | |
a86c6181 AT |
108 | */ |
109 | struct ext4_ext_path { | |
f65e6fba | 110 | ext4_fsblk_t p_block; |
a86c6181 AT |
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 | ||
6873fa0d ES |
122 | /* |
123 | * to be called by ext4_ext_walk_space() | |
124 | * negative retcode - error | |
125 | * positive retcode - signal for ext4_ext_walk_space(), see below | |
126 | * callback must return valid extent (passed or newly created) | |
127 | */ | |
c03f8aa9 | 128 | typedef int (*ext_prepare_callback)(struct inode *, ext4_lblk_t, |
6873fa0d ES |
129 | struct ext4_ext_cache *, |
130 | struct ext4_extent *, void *); | |
131 | ||
132 | #define EXT_CONTINUE 0 | |
133 | #define EXT_BREAK 1 | |
134 | #define EXT_REPEAT 2 | |
a86c6181 | 135 | |
f17722f9 LC |
136 | /* |
137 | * Maximum number of logical blocks in a file; ext4_extent's ee_block is | |
138 | * __le32. | |
139 | */ | |
140 | #define EXT_MAX_BLOCKS 0xffffffff | |
a86c6181 | 141 | |
749269fa AA |
142 | /* |
143 | * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an | |
144 | * initialized extent. This is 2^15 and not (2^16 - 1), since we use the | |
145 | * MSB of ee_len field in the extent datastructure to signify if this | |
146 | * particular extent is an initialized extent or an uninitialized (i.e. | |
147 | * preallocated). | |
148 | * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an | |
149 | * uninitialized extent. | |
150 | * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an | |
151 | * uninitialized one. In other words, if MSB of ee_len is set, it is an | |
152 | * uninitialized extent with only one special scenario when ee_len = 0x8000. | |
153 | * In this case we can not have an uninitialized extent of zero length and | |
154 | * thus we make it as a special case of initialized extent with 0x8000 length. | |
155 | * This way we get better extent-to-group alignment for initialized extents. | |
156 | * Hence, the maximum number of blocks we can have in an *initialized* | |
157 | * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767). | |
158 | */ | |
159 | #define EXT_INIT_MAX_LEN (1UL << 15) | |
160 | #define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1) | |
471d4011 | 161 | |
a86c6181 AT |
162 | |
163 | #define EXT_FIRST_EXTENT(__hdr__) \ | |
164 | ((struct ext4_extent *) (((char *) (__hdr__)) + \ | |
165 | sizeof(struct ext4_extent_header))) | |
166 | #define EXT_FIRST_INDEX(__hdr__) \ | |
167 | ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \ | |
168 | sizeof(struct ext4_extent_header))) | |
169 | #define EXT_HAS_FREE_INDEX(__path__) \ | |
8c55e204 DK |
170 | (le16_to_cpu((__path__)->p_hdr->eh_entries) \ |
171 | < le16_to_cpu((__path__)->p_hdr->eh_max)) | |
a86c6181 AT |
172 | #define EXT_LAST_EXTENT(__hdr__) \ |
173 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
174 | #define EXT_LAST_INDEX(__hdr__) \ | |
175 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1) | |
176 | #define EXT_MAX_EXTENT(__hdr__) \ | |
177 | (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
178 | #define EXT_MAX_INDEX(__hdr__) \ | |
179 | (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1) | |
180 | ||
181 | static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode) | |
182 | { | |
183 | return (struct ext4_extent_header *) EXT4_I(inode)->i_data; | |
184 | } | |
185 | ||
186 | static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh) | |
187 | { | |
188 | return (struct ext4_extent_header *) bh->b_data; | |
189 | } | |
190 | ||
191 | static inline unsigned short ext_depth(struct inode *inode) | |
192 | { | |
193 | return le16_to_cpu(ext_inode_hdr(inode)->eh_depth); | |
194 | } | |
195 | ||
a86c6181 AT |
196 | static inline void |
197 | ext4_ext_invalidate_cache(struct inode *inode) | |
198 | { | |
b05e6ae5 | 199 | EXT4_I(inode)->i_cached_extent.ec_len = 0; |
a86c6181 AT |
200 | } |
201 | ||
a2df2a63 AA |
202 | static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext) |
203 | { | |
749269fa AA |
204 | /* We can not have an uninitialized extent of zero length! */ |
205 | BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0); | |
206 | ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
207 | } |
208 | ||
209 | static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext) | |
210 | { | |
749269fa AA |
211 | /* Extent with ee_len of 0x8000 is treated as an initialized extent */ |
212 | return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN); | |
a2df2a63 AA |
213 | } |
214 | ||
215 | static inline int ext4_ext_get_actual_len(struct ext4_extent *ext) | |
216 | { | |
749269fa AA |
217 | return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ? |
218 | le16_to_cpu(ext->ee_len) : | |
219 | (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN)); | |
a2df2a63 AA |
220 | } |
221 | ||
0031462b MC |
222 | static inline void ext4_ext_mark_initialized(struct ext4_extent *ext) |
223 | { | |
224 | ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext)); | |
225 | } | |
226 | ||
bf89d16f TT |
227 | /* |
228 | * ext4_ext_pblock: | |
229 | * combine low and high parts of physical block number into ext4_fsblk_t | |
230 | */ | |
231 | static inline ext4_fsblk_t ext4_ext_pblock(struct ext4_extent *ex) | |
232 | { | |
233 | ext4_fsblk_t block; | |
234 | ||
235 | block = le32_to_cpu(ex->ee_start_lo); | |
236 | block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1; | |
237 | return block; | |
238 | } | |
239 | ||
240 | /* | |
241 | * ext4_idx_pblock: | |
242 | * combine low and high parts of a leaf physical block number into ext4_fsblk_t | |
243 | */ | |
244 | static inline ext4_fsblk_t ext4_idx_pblock(struct ext4_extent_idx *ix) | |
245 | { | |
246 | ext4_fsblk_t block; | |
247 | ||
248 | block = le32_to_cpu(ix->ei_leaf_lo); | |
249 | block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1; | |
250 | return block; | |
251 | } | |
252 | ||
253 | /* | |
254 | * ext4_ext_store_pblock: | |
255 | * stores a large physical block number into an extent struct, | |
256 | * breaking it into parts | |
257 | */ | |
258 | static inline void ext4_ext_store_pblock(struct ext4_extent *ex, | |
259 | ext4_fsblk_t pb) | |
260 | { | |
261 | ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); | |
262 | ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & | |
263 | 0xffff); | |
264 | } | |
265 | ||
266 | /* | |
267 | * ext4_idx_store_pblock: | |
268 | * stores a large physical block number into an index struct, | |
269 | * breaking it into parts | |
270 | */ | |
271 | static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix, | |
272 | ext4_fsblk_t pb) | |
273 | { | |
274 | ix->ei_leaf_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff)); | |
275 | ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & | |
276 | 0xffff); | |
277 | } | |
278 | ||
9d0be502 | 279 | extern int ext4_ext_calc_metadata_amount(struct inode *inode, |
01f49d0b | 280 | ext4_lblk_t lblocks); |
a86c6181 | 281 | extern int ext4_extent_tree_init(handle_t *, struct inode *); |
ee12b630 MC |
282 | extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode, |
283 | int num, | |
284 | struct ext4_ext_path *path); | |
748de673 AF |
285 | extern int ext4_can_extents_be_merged(struct inode *inode, |
286 | struct ext4_extent *ex1, | |
287 | struct ext4_extent *ex2); | |
0031462b | 288 | extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int); |
725d26d3 AK |
289 | extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t, |
290 | struct ext4_ext_path *); | |
b35905c1 | 291 | extern void ext4_ext_drop_refs(struct ext4_ext_path *); |
7a262f7c | 292 | extern int ext4_ext_check_inode(struct inode *inode); |
3dcf5451 | 293 | #endif /* _EXT4_EXTENTS */ |
a86c6181 | 294 |