extras/volume_id/volume_id/ocfs2.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) Andre Masella <andre@masella.no-ip.org>
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  */
  10
  11 #ifndef _GNU_SOURCE
  12 #define _GNU_SOURCE 1
  13 #endif
  14
  15 #ifdef HAVE_CONFIG_H
  16 #  include <config.h>
  17 #endif
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <unistd.h>
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <ctype.h>
  25
  26 #include "volume_id.h"
  27 #include "logging.h"
  28 #include "util.h"
  29 #include "ocfs2.h"
  30
  31
  32 /* All these values are taken from ocfs2-tools's ocfs2_fs.h */
  33 #define OCFS2_VOL_UUID_LEN                      16
  34 #define OCFS2_MAX_VOL_LABEL_LEN                 64
  35 #define OCFS2_SUPERBLOCK_OFFSET                 0x2000
  36
  37
  38 /* This is the superblock. The OCFS2 header files have structs in structs.
  39 This is one has been simplified since we only care about the superblock.
  40 */
  41
  42 struct ocfs2_super_block {
  43         uint8_t         i_signature[8];                 /* Signature for validation */
  44         uint32_t        i_generation;                   /* Generation number */
  45         int16_t         i_suballoc_slot;                        /* Slot suballocator this inode belongs to */
  46         uint16_t        i_suballoc_bit;                 /* Bit offset in suballocator block group */
  47         uint32_t        i_reserved0;
  48         uint32_t        i_clusters;                     /* Cluster count */
  49         uint32_t        i_uid;                          /* Owner UID */
  50         uint32_t        i_gid;                          /* Owning GID */
  51         uint64_t        i_size;                         /* Size in bytes */
  52         uint16_t        i_mode;                         /* File mode */
  53         uint16_t        i_links_count;                  /* Links count */
  54         uint32_t        i_flags;                                /* File flags */
  55         uint64_t        i_atime;                                /* Access time */
  56         uint64_t        i_ctime;                                /* Creation time */
  57         uint64_t        i_mtime;                                /* Modification time */
  58         uint64_t        i_dtime;                                /* Deletion time */
  59         uint64_t        i_blkno;                                /* Offset on disk, in blocks */
  60         uint64_t        i_last_eb_blk;                  /* Pointer to last extent block */
  61         uint32_t        i_fs_generation;                        /* Generation per fs-instance */
  62         uint32_t        i_atime_nsec;
  63         uint32_t        i_ctime_nsec;
  64         uint32_t        i_mtime_nsec;
  65         uint64_t        i_reserved1[9];
  66         uint64_t        i_pad1;                         /* Generic way to refer to this 64bit union */
  67         /* Normally there is a union of the different block types, but we only care about the superblock. */
  68         uint16_t        s_major_rev_level;
  69         uint16_t        s_minor_rev_level;
  70         uint16_t        s_mnt_count;
  71         int16_t         s_max_mnt_count;
  72         uint16_t        s_state;                                /* File system state */
  73         uint16_t        s_errors;                               /* Behaviour when detecting errors */
  74         uint32_t        s_checkinterval;                        /* Max time between checks */
  75         uint64_t        s_lastcheck;                    /* Time of last check */
  76         uint32_t        s_creator_os;                   /* OS */
  77         uint32_t        s_feature_compat;                       /* Compatible feature set */
  78         uint32_t        s_feature_incompat;             /* Incompatible feature set */
  79         uint32_t        s_feature_ro_compat;            /* Readonly-compatible feature set */
  80         uint64_t        s_root_blkno;                   /* Offset, in blocks, of root directory dinode */
  81         uint64_t        s_system_dir_blkno;             /* Offset, in blocks, of system directory dinode */
  82         uint32_t        s_blocksize_bits;                       /* Blocksize for this fs */
  83         uint32_t        s_clustersize_bits;             /* Clustersize for this fs */
  84         uint16_t        s_max_slots;                    /* Max number of simultaneous mounts before tunefs required */
  85         uint16_t        s_reserved1;
  86         uint32_t        s_reserved2;
  87         uint64_t        s_first_cluster_group;          /* Block offset of 1st cluster group header */
  88         uint8_t         s_label[OCFS2_MAX_VOL_LABEL_LEN];       /* Label for mounting, etc. */
  89         uint8_t         s_uuid[OCFS2_VOL_UUID_LEN];     /* 128-bit uuid */
  90 } __attribute__((__packed__));
  91
  92 int volume_id_probe_ocfs2(struct volume_id *id, uint64_t                off)
  93 {
  94         struct ocfs2_super_block *os;
  95
  96         dbg("probing at offset 0x%llx", (unsigned long long) off);
  97
  98         os = (struct ocfs2_super_block *) volume_id_get_buffer(id, off + OCFS2_SUPERBLOCK_OFFSET, 0x200);
  99         if (os == NULL)
 100                 return -1;
 101
 102         if (memcmp(os->i_signature, "OCFSV2", 6) != 0) {
 103                 return -1;
 104         }
 105
 106         volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 107         volume_id_set_label_raw(id, os->s_label, OCFS2_MAX_VOL_LABEL_LEN < VOLUME_ID_LABEL_SIZE ?
 108                                         OCFS2_MAX_VOL_LABEL_LEN : VOLUME_ID_LABEL_SIZE);
 109         volume_id_set_label_string(id, os->s_label, OCFS2_MAX_VOL_LABEL_LEN < VOLUME_ID_LABEL_SIZE ?
 110                                         OCFS2_MAX_VOL_LABEL_LEN : VOLUME_ID_LABEL_SIZE);
 111         volume_id_set_uuid(id, os->s_uuid, UUID_DCE);
 112         id->type = "ocfs2";
 113         return 0;
 114 }