xref: /freebsd/sys/fs/ext2fs/ext2_extents.h (revision 29fc4075e69fd27de0cded313ac6000165d99f8b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012, 2010 Zheng Liu <lz@freebsd.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 #ifndef _FS_EXT2FS_EXT2_EXTENTS_H_
31 #define	_FS_EXT2FS_EXT2_EXTENTS_H_
32 
33 #include <sys/types.h>
34 
35 #define	EXT4_EXT_MAGIC  0xf30a
36 #define EXT4_MAX_BLOCKS 0xffffffff
37 #define EXT_INIT_MAX_LEN (1UL << 15)
38 #define EXT4_MAX_LEN	(EXT_INIT_MAX_LEN - 1)
39 #define EXT4_EXT_DEPTH_MAX 5
40 
41 #define	EXT4_EXT_CACHE_NO	0
42 #define	EXT4_EXT_CACHE_GAP	1
43 #define	EXT4_EXT_CACHE_IN	2
44 
45 /*
46  * Ext4 extent tail with csum
47  */
48 struct ext4_extent_tail {
49 	uint32_t et_checksum;	/* crc32c(uuid+inum+extent_block) */
50 };
51 
52 /*
53  * Ext4 file system extent on disk.
54  */
55 struct ext4_extent {
56 	uint32_t e_blk;			/* first logical block */
57 	uint16_t e_len;			/* number of blocks */
58 	uint16_t e_start_hi;		/* high 16 bits of physical block */
59 	uint32_t e_start_lo;		/* low 32 bits of physical block */
60 };
61 
62 /*
63  * Extent index on disk.
64  */
65 struct ext4_extent_index {
66 	uint32_t ei_blk;	/* indexes logical blocks */
67 	uint32_t ei_leaf_lo;	/* points to physical block of the
68 				 * next level */
69 	uint16_t ei_leaf_hi;	/* high 16 bits of physical block */
70 	uint16_t ei_unused;
71 };
72 
73 /*
74  * Extent tree header.
75  */
76 struct ext4_extent_header {
77 	uint16_t eh_magic;		/* magic number: 0xf30a */
78 	uint16_t eh_ecount;		/* number of valid entries */
79 	uint16_t eh_max;		/* capacity of store in entries */
80 	uint16_t eh_depth;		/* the depth of extent tree */
81 	uint32_t eh_gen;		/* generation of extent tree */
82 };
83 
84 /*
85  * Save cached extent.
86  */
87 struct ext4_extent_cache {
88 	daddr_t	ec_start;		/* extent start */
89 	uint32_t ec_blk;		/* logical block */
90 	uint32_t ec_len;
91 	uint32_t ec_type;
92 };
93 
94 /*
95  * Save path to some extent.
96  */
97 struct ext4_extent_path {
98 	int index_count;
99 	uint16_t ep_depth;
100 	uint64_t ep_blk;
101 	char *ep_data;
102 	struct ext4_extent *ep_ext;
103 	struct ext4_extent_index *ep_index;
104 	struct ext4_extent_header *ep_header;
105 };
106 
107 #define EXT_FIRST_EXTENT(hdr) ((struct ext4_extent *)(((char *)(hdr)) + \
108     sizeof(struct ext4_extent_header)))
109 #define EXT_FIRST_INDEX(hdr) ((struct ext4_extent_index *)(((char *)(hdr)) + \
110     sizeof(struct ext4_extent_header)))
111 #define EXT_LAST_EXTENT(hdr) (EXT_FIRST_EXTENT((hdr)) + le16toh((hdr)->eh_ecount) - 1)
112 #define EXT_LAST_INDEX(hdr) (EXT_FIRST_INDEX((hdr)) + le16toh((hdr)->eh_ecount) - 1)
113 #define EXT4_EXTENT_TAIL_OFFSET(hdr) (sizeof(struct ext4_extent_header) + \
114     (sizeof(struct ext4_extent) * le16toh((hdr)->eh_max)))
115 #define EXT_HAS_FREE_INDEX(path) \
116     (le16toh((path)->ep_header->eh_ecount) < le16toh((path)->ep_header->eh_max))
117 #define EXT_MAX_EXTENT(hdr) (EXT_FIRST_EXTENT(hdr) + le16toh((hdr)->eh_max) - 1)
118 #define EXT_MAX_INDEX(hdr) (EXT_FIRST_INDEX((hdr)) + le16toh((hdr)->eh_max) - 1)
119 
120 struct inode;
121 struct m_ext2fs;
122 void	ext4_ext_tree_init(struct inode *ip);
123 int	ext4_ext_in_cache(struct inode *, daddr_t, struct ext4_extent *);
124 void	ext4_ext_put_cache(struct inode *, struct ext4_extent *, int);
125 int	ext4_ext_find_extent(struct inode *, daddr_t, struct ext4_extent_path **);
126 void	ext4_ext_path_free(struct ext4_extent_path *path);
127 int	ext4_ext_remove_space(struct inode *ip, off_t length, int flags,
128     struct ucred *cred, struct thread *td);
129 int	ext4_ext_get_blocks(struct inode *ip, int64_t iblock,
130     unsigned long max_blocks, struct ucred *cred, struct buf **bpp,
131     int *allocate, daddr_t *);
132 #ifdef EXT2FS_PRINT_EXTENTS
133 int	ext4_ext_walk(struct inode *ip);
134 #endif
135 
136 #endif	/* !_FS_EXT2FS_EXT2_EXTENTS_H_ */
137