extras/volume_id/lib/gfs.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2006 Red Hat, Inc. <redhat.com>
   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 "libvolume_id.h"
  27 #include "util.h"
  28
  29 /* Common gfs/gfs2 constants: */
  30 #define GFS_MAGIC               0x01161970
  31 #define GFS_DEFAULT_BSIZE       4096
  32 #define GFS_SUPERBLOCK_OFFSET   (0x10 * GFS_DEFAULT_BSIZE)
  33 #define GFS_METATYPE_SB         1
  34 #define GFS_FORMAT_SB           100
  35 #define GFS_LOCKNAME_LEN        64
  36
  37 /* gfs1 constants: */
  38 #define GFS_FORMAT_FS           1309
  39 #define GFS_FORMAT_MULTI        1401
  40 /* gfs2 constants: */
  41 #define GFS2_FORMAT_FS          1801
  42 #define GFS2_FORMAT_MULTI       1900
  43
  44 struct gfs2_meta_header {
  45         uint32_t mh_magic;
  46         uint32_t mh_type;
  47         uint64_t __pad0;          /* Was generation number in gfs1 */
  48         uint32_t mh_format;
  49         uint32_t __pad1;          /* Was incarnation number in gfs1 */
  50 };
  51
  52 struct gfs2_inum {
  53         uint64_t no_formal_ino;
  54         uint64_t no_addr;
  55 };
  56
  57 struct gfs2_sb {
  58         struct gfs2_meta_header sb_header;
  59
  60         uint32_t sb_fs_format;
  61         uint32_t sb_multihost_format;
  62         uint32_t  __pad0;  /* Was superblock flags in gfs1 */
  63
  64         uint32_t sb_bsize;
  65         uint32_t sb_bsize_shift;
  66         uint32_t __pad1;   /* Was journal segment size in gfs1 */
  67
  68         struct gfs2_inum sb_master_dir; /* Was jindex dinode in gfs1 */
  69         struct gfs2_inum __pad2; /* Was rindex dinode in gfs1 */
  70         struct gfs2_inum sb_root_dir;
  71
  72         char sb_lockproto[GFS_LOCKNAME_LEN];
  73         char sb_locktable[GFS_LOCKNAME_LEN];
  74         /* In gfs1, quota and license dinodes followed */
  75 } PACKED;
  76
  77 static int volume_id_probe_gfs_generic(struct volume_id *id, uint64_t off, int vers)
  78 {
  79         struct gfs2_sb *sbd;
  80
  81         info("probing at offset 0x%llx\n", (unsigned long long) off);
  82
  83         sbd = (struct gfs2_sb *)
  84                 volume_id_get_buffer(id, off + GFS_SUPERBLOCK_OFFSET, sizeof(struct gfs2_sb));
  85         if (sbd == NULL)
  86                 return -1;
  87
  88         if (be32_to_cpu(sbd->sb_header.mh_magic) == GFS_MAGIC &&
  89                 be32_to_cpu(sbd->sb_header.mh_type) == GFS_METATYPE_SB &&
  90                 be32_to_cpu(sbd->sb_header.mh_format) == GFS_FORMAT_SB) {
  91                 if (vers == 1) {
  92                         if (be32_to_cpu(sbd->sb_fs_format) != GFS_FORMAT_FS ||
  93                                 be32_to_cpu(sbd->sb_multihost_format) != GFS_FORMAT_MULTI)
  94                                 return -1; /* not gfs1 */
  95                         id->type = "gfs";
  96                 }
  97                 else if (vers == 2) {
  98                         if (be32_to_cpu(sbd->sb_fs_format) != GFS2_FORMAT_FS ||
  99                                 be32_to_cpu(sbd->sb_multihost_format) != GFS2_FORMAT_MULTI)
 100                                 return -1; /* not gfs2 */
 101                         id->type = "gfs2";
 102                 }
 103                 else
 104                         return -1;
 105                 strcpy(id->type_version, "1");
 106                 volume_id_set_usage(id, VOLUME_ID_FILESYSTEM);
 107                 return 0;
 108         }
 109         return -1;
 110 }
 111
 112 int volume_id_probe_gfs(struct volume_id *id, uint64_t off, uint64_t size)
 113 {
 114         return volume_id_probe_gfs_generic(id, off, 1);
 115 }
 116
 117 int volume_id_probe_gfs2(struct volume_id *id, uint64_t off, uint64_t size)
 118 {
 119         return volume_id_probe_gfs_generic(id, off, 2);
 120 }