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-rw-r--r--include/linux/ext4_fs_extents.h196
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diff --git a/include/linux/ext4_fs_extents.h b/include/linux/ext4_fs_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 _LINUX_EXT4_EXTENTS
20#define _LINUX_EXT4_EXTENTS
21
22#include <linux/ext4_fs.h>
23
24/*
25 * with AGRESSIVE_TEST defined capacity of index/leaf blocks
26 * become very little, so index split, in-depth growing and
27 * other hard changes happens much more often
28 * this is for debug purposes only
29 */
30#define AGRESSIVE_TEST_
31
32/*
33 * with EXTENTS_STATS defined number of blocks and extents
34 * are collected in truncate path. they'll be showed at
35 * umount time
36 */
37#define EXTENTS_STATS__
38
39/*
40 * if CHECK_BINSEARCH defined, then results of binary search
41 * will be checked by linear search
42 */
43#define CHECK_BINSEARCH__
44
45/*
46 * if EXT_DEBUG is defined you can use 'extdebug' mount option
47 * to get lots of info 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 * first 12 bytes store ext4_extent_header
66 * the remain stores array of ext4_extent
67 */
68
69/*
70 * this is extent on-disk structure
71 * it's used at the bottom of the tree
72 */
73struct 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; /* low 32 bigs of physical block */
78};
79
80/*
81 * this is index on-disk structure
82 * it's used at all the levels, but the bottom
83 */
84struct 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 *
87 * level. leaf or next index could bet here */
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 */
95struct 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 underlaying 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 */
110struct ext4_ext_path {
111 __u32 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 * 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 */
133typedef 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
144
145#define EXT_FIRST_EXTENT(__hdr__) \
146 ((struct ext4_extent *) (((char *) (__hdr__)) + \
147 sizeof(struct ext4_extent_header)))
148#define EXT_FIRST_INDEX(__hdr__) \
149 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
150 sizeof(struct ext4_extent_header)))
151#define EXT_HAS_FREE_INDEX(__path__) \
152 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
153 < le16_to_cpu((__path__)->p_hdr->eh_max))
154#define EXT_LAST_EXTENT(__hdr__) \
155 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
156#define EXT_LAST_INDEX(__hdr__) \
157 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
158#define EXT_MAX_EXTENT(__hdr__) \
159 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
160#define EXT_MAX_INDEX(__hdr__) \
161 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
162
163static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
164{
165 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
166}
167
168static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
169{
170 return (struct ext4_extent_header *) bh->b_data;
171}
172
173static inline unsigned short ext_depth(struct inode *inode)
174{
175 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
176}
177
178static inline void ext4_ext_tree_changed(struct inode *inode)
179{
180 EXT4_I(inode)->i_ext_generation++;
181}
182
183static inline void
184ext4_ext_invalidate_cache(struct inode *inode)
185{
186 EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
187}
188
189extern int ext4_extent_tree_init(handle_t *, struct inode *);
190extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
191extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *);
192extern int ext4_ext_walk_space(struct inode *, unsigned long, unsigned long, ext_prepare_callback, void *);
193extern struct ext4_ext_path * ext4_ext_find_extent(struct inode *, int, struct ext4_ext_path *);
194
195#endif /* _LINUX_EXT4_EXTENTS */
196
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-28 14:55:44 -0500