release/src/router/busybox/util-linux/volume_id/nilfs.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
   5  * Copyright (C) 2012 S-G Bergh <sgb@systemasis.org>
   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 NILFS_UUID_SIZE 16
  25 #define NILFS_LABEL_SIZE 80
  26 #define NILFS_SB1_OFFSET 0x400
  27 #define NILFS_SB2_OFFSET 0x1000
  28 #define NILFS_MAGIC 0x3434
  29
  30 struct nilfs2_super_block {
  31 /* 0x00 */      uint32_t s_rev_level;                           // Major revision level.
  32 /* 0x04 */      uint16_t s_minor_rev_level;                     // Minor revision level.
  33 /* 0x06 */      uint16_t s_magic;                               // Magic signature.
  34 /* 0x08 */      uint16_t s_bytes;
  35 /* 0x0A */      uint16_t s_flags;
  36 /* 0x0C */      uint32_t s_crc_seed;
  37 /* 0x10 */      uint32_t s_sum;
  38 /* 0x14 */      uint32_t s_log_block_size;
  39 /* 0x18 */      uint64_t s_nsegments;
  40 /* 0x20 */      uint64_t s_dev_size;                            // Block device size in bytes.
  41 /* 0x28 */      uint64_t s_first_data_block;
  42 /* 0x30 */      uint32_t s_blocks_per_segment;
  43 /* 0x34 */      uint32_t s_r_segments_percentage;
  44 /* 0x38 */      uint64_t s_last_cno;
  45 /* 0x40 */      uint64_t s_last_pseg;
  46 /* 0x48 */      uint64_t s_last_seq;
  47 /* 0x50 */      uint64_t s_free_blocks_count;
  48 /* 0x58 */      uint64_t s_ctime;
  49 /* 0x60 */      uint64_t s_mtime;
  50 /* 0x68 */      uint64_t s_wtime;
  51 /* 0x70 */      uint16_t s_mnt_count;
  52 /* 0x72 */      uint16_t s_max_mnt_count;
  53 /* 0x74 */      uint16_t s_state;
  54 /* 0x76 */      uint16_t s_errors;
  55 /* 0x78 */      uint64_t s_lastcheck;
  56 /* 0x80 */      uint32_t s_checkinterval;
  57 /* 0x84 */      uint32_t s_creator_os;
  58 /* 0x88 */      uint16_t s_def_resuid;
  59 /* 0x8A */      uint16_t s_def_resgid;
  60 /* 0x8C */      uint32_t s_first_ino;
  61 /* 0x90 */      uint16_t s_inode_size;
  62 /* 0x92 */      uint16_t s_dat_entry_size;
  63 /* 0x94 */      uint16_t s_checkpoint_size;
  64 /* 0x96 */      uint16_t s_segment_usage_size;
  65 /* 0x98 */      uint8_t s_uuid[NILFS_UUID_SIZE];                // 128-bit UUID for volume.
  66 /* 0xA8 */      uint8_t s_volume_name[NILFS_LABEL_SIZE];        // Volume label.
  67 /* 0xF8 */      // ...
  68 } PACKED;
  69
  70 int FAST_FUNC volume_id_probe_nilfs(struct volume_id *id /*,uint64_t off*/)
  71 {
  72         struct nilfs2_super_block *sb;
  73
  74         // Primary super block
  75         dbg("nilfs: probing at offset 0x%x", NILFS_SB1_OFFSET);
  76
  77         sb = volume_id_get_buffer(id, NILFS_SB1_OFFSET, sizeof(*sb));
  78
  79         if (sb == NULL)
  80                 return -1;
  81
  82         if (sb->s_magic != NILFS_MAGIC)
  83                 return -1;
  84
  85         // The secondary superblock is not always used, so ignore it for now.
  86         // When used it is at 4K from the end of the partition (sb->s_dev_size - NILFS_SB2_OFFSET).
  87
  88         volume_id_set_label_string(id, sb->s_volume_name, NILFS_LABEL_SIZE < VOLUME_ID_LABEL_SIZE ?
  89                                 NILFS_LABEL_SIZE : VOLUME_ID_LABEL_SIZE);
  90         volume_id_set_uuid(id, sb->s_uuid, UUID_DCE);
  91
  92         if (sb->s_rev_level == 2)
  93                 IF_FEATURE_BLKID_TYPE(id->type = "nilfs2");
  94
  95         return 0;
  96 }