Contents of /tags/mkinitrd-6_2_0/util-linux/volume_id/btrfs.c
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Sun May 30 11:53:18 2010 UTC (14 years, 4 months ago) by niro
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Sun May 30 11:53:18 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 2948 byte(s)
tagged 'mkinitrd-6_2_0'
1 | /* |
2 | * volume_id - reads filesystem label and uuid |
3 | * |
4 | * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org> |
5 | * Copyright (C) 2009 Vladimir Dronnikov <dronnikov@gmail.com> |
6 | * |
7 | * This library is free software; you can redistribute it and/or |
8 | * modify it under the terms of the GNU Lesser General Public |
9 | * License as published by the Free Software Foundation; either |
10 | * version 2.1 of the License, or (at your option) any later version. |
11 | * |
12 | * This library is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | * Lesser General Public License for more details. |
16 | * |
17 | * You should have received a copy of the GNU Lesser General Public |
18 | * License along with this library; if not, write to the Free Software |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
20 | */ |
21 | |
22 | #include "volume_id_internal.h" |
23 | |
24 | #define BTRFS_UUID_SIZE 16 |
25 | #define BTRFS_LABEL_SIZE 256 |
26 | #define BTRFS_CSUM_SIZE 32 |
27 | #define BTRFS_FSID_SIZE 16 |
28 | |
29 | #define BTRFS_MAGIC "_BHRfS_M" |
30 | |
31 | struct btrfs_dev_item { |
32 | uint64_t devid; |
33 | uint64_t total_bytes; |
34 | uint64_t bytes_used; |
35 | uint32_t io_align; |
36 | uint32_t io_width; |
37 | uint32_t sector_size; |
38 | uint64_t type; |
39 | uint64_t generation; |
40 | uint64_t start_offset; |
41 | uint32_t dev_group; |
42 | uint8_t seek_speed; |
43 | uint8_t bandwidth; |
44 | uint8_t uuid[BTRFS_UUID_SIZE]; |
45 | uint8_t fsid[BTRFS_UUID_SIZE]; |
46 | } PACKED; |
47 | |
48 | struct btrfs_super_block { |
49 | uint8_t csum[BTRFS_CSUM_SIZE]; |
50 | uint8_t fsid[BTRFS_FSID_SIZE]; // UUID |
51 | uint64_t bytenr; |
52 | uint64_t flags; |
53 | uint8_t magic[8]; |
54 | uint64_t generation; |
55 | uint64_t root; |
56 | uint64_t chunk_root; |
57 | uint64_t log_root; |
58 | uint64_t log_root_transid; |
59 | uint64_t total_bytes; |
60 | uint64_t bytes_used; |
61 | uint64_t root_dir_objectid; |
62 | uint64_t num_devices; |
63 | uint32_t sectorsize; |
64 | uint32_t nodesize; |
65 | uint32_t leafsize; |
66 | uint32_t stripesize; |
67 | uint32_t sys_chunk_array_size; |
68 | uint64_t chunk_root_generation; |
69 | uint64_t compat_flags; |
70 | uint64_t compat_ro_flags; |
71 | uint64_t incompat_flags; |
72 | uint16_t csum_type; |
73 | uint8_t root_level; |
74 | uint8_t chunk_root_level; |
75 | uint8_t log_root_level; |
76 | struct btrfs_dev_item dev_item; |
77 | uint8_t label[BTRFS_LABEL_SIZE]; // LABEL |
78 | // ... |
79 | } PACKED; |
80 | |
81 | int FAST_FUNC volume_id_probe_btrfs(struct volume_id *id /*,uint64_t off*/) |
82 | { |
83 | // btrfs has superblocks at 64K, 64M and 256G |
84 | // minimum btrfs size is 256M |
85 | // so we never step out the device if we analyze |
86 | // the first and the second superblocks |
87 | struct btrfs_super_block *sb; |
88 | unsigned off = 64; |
89 | |
90 | while (off < 64*1024*1024) { |
91 | off *= 1024; |
92 | dbg("btrfs: probing at offset 0x%x", off); |
93 | |
94 | sb = volume_id_get_buffer(id, off, sizeof(*sb)); |
95 | if (sb == NULL) |
96 | return -1; |
97 | |
98 | if (memcmp(sb->magic, BTRFS_MAGIC, 8) != 0) |
99 | return -1; |
100 | } |
101 | |
102 | // N.B.: btrfs natively supports 256 (>VOLUME_ID_LABEL_SIZE) size labels |
103 | volume_id_set_label_string(id, sb->label, VOLUME_ID_LABEL_SIZE); |
104 | volume_id_set_uuid(id, sb->fsid, UUID_DCE); |
105 | |
106 | return 0; |
107 | } |