xref: /freebsd/sys/fs/ext2fs/ext2_extents.h (revision 5dae51da3da0cc94d17bd67b308fad304ebec7e0)
1 /*-
2  * Copyright (c) 2012, 2010 Zheng Liu <lz@freebsd.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 #ifndef _FS_EXT2FS_EXT2_EXTENTS_H_
29 #define	_FS_EXT2FS_EXT2_EXTENTS_H_
30 
31 #include <sys/types.h>
32 
33 #define	EXT4_EXT_MAGIC  0xf30a
34 
35 #define	EXT4_EXT_CACHE_NO	0
36 #define	EXT4_EXT_CACHE_GAP	1
37 #define	EXT4_EXT_CACHE_IN	2
38 
39 /*
40  * Ext4 file system extent on disk.
41  */
42 struct ext4_extent {
43 	uint32_t e_blk;		/* first logical block */
44 	uint16_t e_len;		/* number of blocks */
45 	uint16_t e_start_hi;	/* high 16 bits of physical block */
46 	uint32_t e_start_lo;	/* low 32 bits of physical block */
47 };
48 
49 /*
50  * Extent index on disk.
51  */
52 struct ext4_extent_index {
53 	uint32_t ei_blk;	/* indexes logical blocks */
54 	uint32_t ei_leaf_lo;	/* points to physical block of the
55 				 * next level */
56 	uint16_t ei_leaf_hi;	/* high 16 bits of physical block */
57 	uint16_t ei_unused;
58 };
59 
60 /*
61  * Extent tree header.
62  */
63 struct ext4_extent_header {
64 	uint16_t eh_magic;	/* magic number: 0xf30a */
65 	uint16_t eh_ecount;	/* number of valid entries */
66 	uint16_t eh_max;	/* capacity of store in entries */
67 	uint16_t eh_depth;	/* the depth of extent tree */
68 	uint32_t eh_gen;	/* generation of extent tree */
69 };
70 
71 /*
72  * Save cached extent.
73  */
74 struct ext4_extent_cache {
75 	daddr_t	ec_start;	/* extent start */
76 	uint32_t ec_blk;	/* logical block */
77 	uint32_t ec_len;
78 	uint32_t ec_type;
79 };
80 
81 /*
82  * Save path to some extent.
83  */
84 struct ext4_extent_path {
85 	uint16_t ep_depth;
86 	struct buf *ep_bp;
87 	bool ep_is_sparse;
88 	union {
89 		struct ext4_extent ep_sparse_ext;
90 		struct ext4_extent *ep_ext;
91 	};
92 	struct ext4_extent_index *ep_index;
93 	struct ext4_extent_header *ep_header;
94 };
95 
96 struct inode;
97 struct m_ext2fs;
98 int	ext4_ext_in_cache(struct inode *, daddr_t, struct ext4_extent *);
99 void	ext4_ext_put_cache(struct inode *, struct ext4_extent *, int);
100 struct ext4_extent_path *ext4_ext_find_extent(struct m_ext2fs *fs,
101     struct inode *, daddr_t, struct ext4_extent_path *);
102 
103 #endif /* !_FS_EXT2FS_EXT2_EXTENTS_H_ */
104