source: branches/3.2/mindi-busybox/util-linux/volume_id/btrfs.c @ 3232

Last change on this file since 3232 was 3232, checked in by bruno, 5 years ago
  • Update mindi-busybox to 1.21.1
  • Property svn:eol-style set to native
File size: 2.9 KB
Line 
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
31struct 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
48struct 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
81int 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    IF_FEATURE_BLKID_TYPE(id->type = "btrfs";)
106
107    return 0;
108}
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