1 /*
2 * Copyright (c) 2003,2004 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_EXT3_EXTENTS
20 #define _LINUX_EXT3_EXTENTS
21
22 /*
23 * with AGRESSIVE_TEST defined capacity of index/leaf blocks
24 * become very little, so index split, in-depth growing and
25 * other hard changes happens much more often
26 * this is for debug purposes only
27 */
28 #define AGRESSIVE_TEST_
29
30 /*
31 * if CHECK_BINSEARCH defined, then results of binary search
32 * will be checked by linear search
33 */
34 #define CHECK_BINSEARCH_
35
36 /*
37 * if EXT_DEBUG is defined you can use 'extdebug' mount option
38 * to get lots of info what's going on
39 */
40 //#define EXT_DEBUG
41 #ifdef EXT_DEBUG
42 #define ext_debug(tree,fmt,a...) \
43 do { \
44 if (test_opt((tree)->inode->i_sb, EXTDEBUG)) \
45 printk(fmt, ##a); \
46 } while (0);
47 #else
48 #define ext_debug(tree,fmt,a...)
49 #endif
50
51 /*
52 * if EXT_STATS is defined then stats numbers are collected
53 * these number will be displayed at umount time
54 */
55 #define EXT_STATS_
56
57
58 #define EXT3_ALLOC_NEEDED 3 /* block bitmap + group desc. + sb */
59
60 /*
61 * ext3_inode has i_block array (total 60 bytes)
62 * first 4 bytes are used to store:
63 * - tree depth (0 mean there is no tree yet. all extents in the inode)
64 * - number of alive extents in the inode
65 */
66
67 /*
68 * this is extent on-disk structure
69 * it's used at the bottom of the tree
70 */
71 struct ext3_extent {
72 __u32 ee_block; /* first logical block extent covers */
73 __u16 ee_len; /* number of blocks covered by extent */
74 __u16 ee_start_hi; /* high 16 bits of physical block */
75 __u32 ee_start; /* low 32 bigs of physical block */
76 };
77
78 /*
79 * this is index on-disk structure
80 * it's used at all the levels, but the bottom
81 */
82 struct ext3_extent_idx {
83 __u32 ei_block; /* index covers logical blocks from 'block' */
84 __u32 ei_leaf; /* pointer to the physical block of the next *
85 * level. leaf or next index could bet here */
86 __u16 ei_leaf_hi; /* high 16 bits of physical block */
87 __u16 ei_unused;
88 };
89
90 /*
91 * each block (leaves and indexes), even inode-stored has header
92 */
93 struct ext3_extent_header {
94 __u16 eh_magic; /* probably will support different formats */
95 __u16 eh_entries; /* number of valid entries */
96 __u16 eh_max; /* capacity of store in entries */
97 __u16 eh_depth; /* has tree real underlaying blocks? */
98 __u32 eh_generation; /* generation of the tree */
99 };
100
101 #define EXT3_EXT_MAGIC 0xf30a
102
103 /*
104 * array of ext3_ext_path contains path to some extent
105 * creation/lookup routines use it for traversal/splitting/etc
106 * truncate uses it to simulate recursive walking
107 */
108 struct ext3_ext_path {
109 __u32 p_block;
110 __u16 p_depth;
111 struct ext3_extent *p_ext;
112 struct ext3_extent_idx *p_idx;
113 struct ext3_extent_header *p_hdr;
114 struct buffer_head *p_bh;
115 };
116
117 /*
118 * structure for external API
119 */
120
121 #define EXT_CONTINUE 0
122 #define EXT_BREAK 1
123 #define EXT_REPEAT 2
124
125
126 #define EXT_MAX_BLOCK 0xffffffff
127 #define EXT_CACHE_MARK 0xffff
128
129
130 #define EXT_FIRST_EXTENT(__hdr__) \
131 ((struct ext3_extent *) (((char *) (__hdr__)) + \
132 sizeof(struct ext3_extent_header)))
133 #define EXT_FIRST_INDEX(__hdr__) \
134 ((struct ext3_extent_idx *) (((char *) (__hdr__)) + \
135 sizeof(struct ext3_extent_header)))
136 #define EXT_HAS_FREE_INDEX(__path__) \
137 ((__path__)->p_hdr->eh_entries < (__path__)->p_hdr->eh_max)
138 #define EXT_LAST_EXTENT(__hdr__) \
139 (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_entries - 1)
140 #define EXT_LAST_INDEX(__hdr__) \
141 (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_entries - 1)
142 #define EXT_MAX_EXTENT(__hdr__) \
143 (EXT_FIRST_EXTENT((__hdr__)) + (__hdr__)->eh_max - 1)
144 #define EXT_MAX_INDEX(__hdr__) \
145 (EXT_FIRST_INDEX((__hdr__)) + (__hdr__)->eh_max - 1)
146
147 #define EXT_ROOT_HDR(tree) \
148 ((struct ext3_extent_header *) (tree)->root)
149 #define EXT_BLOCK_HDR(bh) \
150 ((struct ext3_extent_header *) (bh)->b_data)
151 #define EXT_DEPTH(_t_) \
152 (((struct ext3_extent_header *)((_t_)->root))->eh_depth)
153 #define EXT_GENERATION(_t_) \
154 (((struct ext3_extent_header *)((_t_)->root))->eh_generation)
155
156
157 #define EXT_ASSERT(__x__) if (!(__x__)) BUG();
158
159
160 /*
161 * this structure is used to gather extents from the tree via ioctl
162 */
163 struct ext3_extent_buf {
164 unsigned long start;
165 int buflen;
166 void *buffer;
167 void *cur;
168 int err;
169 };
170
171 /*
172 * this structure is used to collect stats info about the tree
173 */
174 struct ext3_extent_tree_stats {
175 int depth;
176 int extents_num;
177 int leaf_num;
178 };
179
180 #ifdef __KERNEL__
181 /*
182 * ext3_extents_tree is used to pass initial information
183 * to top-level extents API
184 */
185 struct ext3_extents_helpers;
186 struct ext3_extents_tree {
187 struct inode *inode; /* inode which tree belongs to */
188 void *root; /* ptr to data top of tree resides at */
189 void *buffer; /* will be passed as arg to ^^ routines */
190 int buffer_len;
191 void *private;
192 struct ext3_extent *cex;/* last found extent */
193 struct ext3_extents_helpers *ops;
194 };
195
196 struct ext3_extents_helpers {
197 int (*get_write_access)(handle_t *h, void *buffer);
198 int (*mark_buffer_dirty)(handle_t *h, void *buffer);
199 int (*mergable)(struct ext3_extent *ex1, struct ext3_extent *ex2);
200 int (*remove_extent_credits)(struct ext3_extents_tree *,
201 struct ext3_extent *, unsigned long,
202 unsigned long);
203 int (*remove_extent)(struct ext3_extents_tree *,
204 struct ext3_extent *, unsigned long,
205 unsigned long);
206 int (*new_block)(handle_t *, struct ext3_extents_tree *,
207 struct ext3_ext_path *, struct ext3_extent *,
208 int *);
209 };
210
211 /*
212 * to be called by ext3_ext_walk_space()
213 * negative retcode - error
214 * positive retcode - signal for ext3_ext_walk_space(), see below
215 * callback must return valid extent (passed or newly created)
216 */
217 typedef int (*ext_prepare_callback)(struct ext3_extents_tree *,
218 struct ext3_ext_path *,
219 struct ext3_extent *, int);
220 void ext3_init_tree_desc(struct ext3_extents_tree *, struct inode *);
221 extern int ext3_extent_tree_init(handle_t *, struct ext3_extents_tree *);
222 extern int ext3_ext_calc_credits_for_insert(struct ext3_extents_tree *, struct ext3_ext_path *);
223 extern int ext3_ext_insert_extent(handle_t *, struct ext3_extents_tree *, struct ext3_ext_path *, struct ext3_extent *);
224 extern int ext3_ext_walk_space(struct ext3_extents_tree *, unsigned long, unsigned long, ext_prepare_callback);
225 extern int ext3_ext_remove_space(struct ext3_extents_tree *, unsigned long, unsigned long);
226 extern struct ext3_ext_path * ext3_ext_find_extent(struct ext3_extents_tree *, int, struct ext3_ext_path *);
227
228 static inline void
ext3_ext_invalidate_cache(struct ext3_extents_tree * tree)229 ext3_ext_invalidate_cache(struct ext3_extents_tree *tree)
230 {
231 if (tree->cex)
232 tree->cex->ee_len = 0;
233 }
234 #endif /* __KERNEL__ */
235
236
237 #endif /* _LINUX_EXT3_EXTENTS */
238
239