fs/efs/super.c

   1 /*
   2  * super.c
   3  *
   4  * Copyright (c) 1999 Al Smith
   5  *
   6  * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/efs_fs.h>
  12 #include <linux/efs_vh.h>
  13 #include <linux/efs_fs_sb.h>
  14 #include <linux/slab.h>
  15 #include <linux/buffer_head.h>
  16 #include <linux/vfs.h>
  17
  18 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  19 static int efs_fill_super(struct super_block *s, void *d, int silent);
  20
  21 static int efs_get_sb(struct file_system_type *fs_type,
  22         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  23 {
  24         return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super, mnt);
  25 }
  26
  27 static struct file_system_type efs_fs_type = {
  28         .owner          = THIS_MODULE,
  29         .name           = "efs",
  30         .get_sb         = efs_get_sb,
  31         .kill_sb        = kill_block_super,
  32         .fs_flags       = FS_REQUIRES_DEV,
  33 };
  34
  35 static struct pt_types sgi_pt_types[] = {
  36         {0x00,          "SGI vh"},
  37         {0x01,          "SGI trkrepl"},
  38         {0x02,          "SGI secrepl"},
  39         {0x03,          "SGI raw"},
  40         {0x04,          "SGI bsd"},
  41         {SGI_SYSV,      "SGI sysv"},
  42         {0x06,          "SGI vol"},
  43         {SGI_EFS,       "SGI efs"},
  44         {0x08,          "SGI lv"},
  45         {0x09,          "SGI rlv"},
  46         {0x0A,          "SGI xfs"},
  47         {0x0B,          "SGI xfslog"},
  48         {0x0C,          "SGI xlv"},
  49         {0x82,          "Linux swap"},
  50         {0x83,          "Linux native"},
  51         {0,             NULL}
  52 };
  53
  54
  55 static struct kmem_cache * efs_inode_cachep;
  56
  57 static struct inode *efs_alloc_inode(struct super_block *sb)
  58 {
  59         struct efs_inode_info *ei;
  60         ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  61         if (!ei)
  62                 return NULL;
  63         return &ei->vfs_inode;
  64 }
  65
  66 static void efs_destroy_inode(struct inode *inode)
  67 {
  68         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  69 }
  70
  71 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
  72 {
  73         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  74
  75         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
  76             SLAB_CTOR_CONSTRUCTOR)
  77                 inode_init_once(&ei->vfs_inode);
  78 }
  79
  80 static int init_inodecache(void)
  81 {
  82         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  83                                 sizeof(struct efs_inode_info),
  84                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  85                                 init_once, NULL);
  86         if (efs_inode_cachep == NULL)
  87                 return -ENOMEM;
  88         return 0;
  89 }
  90
  91 static void destroy_inodecache(void)
  92 {
  93         kmem_cache_destroy(efs_inode_cachep);
  94 }
  95
  96 static void efs_put_super(struct super_block *s)
  97 {
  98         kfree(s->s_fs_info);
  99         s->s_fs_info = NULL;
 100 }
 101
 102 static int efs_remount(struct super_block *sb, int *flags, char *data)
 103 {
 104         *flags |= MS_RDONLY;
 105         return 0;
 106 }
 107
 108 static const struct super_operations efs_superblock_operations = {
 109         .alloc_inode    = efs_alloc_inode,
 110         .destroy_inode  = efs_destroy_inode,
 111         .read_inode     = efs_read_inode,
 112         .put_super      = efs_put_super,
 113         .statfs         = efs_statfs,
 114         .remount_fs     = efs_remount,
 115 };
 116
 117 static struct export_operations efs_export_ops = {
 118         .get_parent     = efs_get_parent,
 119 };
 120
 121 static int __init init_efs_fs(void) {
 122         int err;
 123         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 124         err = init_inodecache();
 125         if (err)
 126                 goto out1;
 127         err = register_filesystem(&efs_fs_type);
 128         if (err)
 129                 goto out;
 130         return 0;
 131 out:
 132         destroy_inodecache();
 133 out1:
 134         return err;
 135 }
 136
 137 static void __exit exit_efs_fs(void) {
 138         unregister_filesystem(&efs_fs_type);
 139         destroy_inodecache();
 140 }
 141
 142 module_init(init_efs_fs)
 143 module_exit(exit_efs_fs)
 144
 145 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 146         int             i;
 147         __be32          cs, *ui;
 148         int             csum;
 149         efs_block_t     sblock = 0; /* shuts up gcc */
 150         struct pt_types *pt_entry;
 151         int             pt_type, slice = -1;
 152
 153         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 154                 /*
 155                  * assume that we're dealing with a partition and allow
 156                  * read_super() to try and detect a valid superblock
 157                  * on the next block.
 158                  */
 159                 return 0;
 160         }
 161
 162         ui = ((__be32 *) (vh + 1)) - 1;
 163         for(csum = 0; ui >= ((__be32 *) vh);) {
 164                 cs = *ui--;
 165                 csum += be32_to_cpu(cs);
 166         }
 167         if (csum) {
 168                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 169                 return 0;
 170         }
 171
 172 #ifdef DEBUG
 173         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 174
 175         for(i = 0; i < NVDIR; i++) {
 176                 int     j;
 177                 char    name[VDNAMESIZE+1];
 178
 179                 for(j = 0; j < VDNAMESIZE; j++) {
 180                         name[j] = vh->vh_vd[i].vd_name[j];
 181                 }
 182                 name[j] = (char) 0;
 183
 184                 if (name[0]) {
 185                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 186                                 name,
 187                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 188                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 189                 }
 190         }
 191 #endif
 192
 193         for(i = 0; i < NPARTAB; i++) {
 194                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 195                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 196                         if (pt_type == pt_entry->pt_type) break;
 197                 }
 198 #ifdef DEBUG
 199                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 200                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 201                                 i,
 202                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 203                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 204                                 pt_type,
 205                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 206                 }
 207 #endif
 208                 if (IS_EFS(pt_type)) {
 209                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 210                         slice = i;
 211                 }
 212         }
 213
 214         if (slice == -1) {
 215                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 216 #ifdef DEBUG
 217         } else {
 218                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 219                         slice,
 220                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 221                         sblock);
 222 #endif
 223         }
 224         return sblock;
 225 }
 226
 227 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 228
 229         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 230                 return -1;
 231
 232         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 233         sb->total_blocks = be32_to_cpu(super->fs_size);
 234         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 235         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 236         sb->data_free    = be32_to_cpu(super->fs_tfree);
 237         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 238         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 239         sb->total_groups = be16_to_cpu(super->fs_ncg);
 240
 241         return 0;
 242 }
 243
 244 static int efs_fill_super(struct super_block *s, void *d, int silent)
 245 {
 246         struct efs_sb_info *sb;
 247         struct buffer_head *bh;
 248         struct inode *root;
 249
 250         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 251         if (!sb)
 252                 return -ENOMEM;
 253         s->s_fs_info = sb;
 254
 255         s->s_magic              = EFS_SUPER_MAGIC;
 256         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 257                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 258                         EFS_BLOCKSIZE);
 259                 goto out_no_fs_ul;
 260         }
 261
 262         /* read the vh (volume header) block */
 263         bh = sb_bread(s, 0);
 264
 265         if (!bh) {
 266                 printk(KERN_ERR "EFS: cannot read volume header\n");
 267                 goto out_no_fs_ul;
 268         }
 269
 270         /*
 271          * if this returns zero then we didn't find any partition table.
 272          * this isn't (yet) an error - just assume for the moment that
 273          * the device is valid and go on to search for a superblock.
 274          */
 275         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 276         brelse(bh);
 277
 278         if (sb->fs_start == -1) {
 279                 goto out_no_fs_ul;
 280         }
 281
 282         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 283         if (!bh) {
 284                 printk(KERN_ERR "EFS: cannot read superblock\n");
 285                 goto out_no_fs_ul;
 286         }
 287
 288         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 289 #ifdef DEBUG
 290                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 291 #endif
 292                 brelse(bh);
 293                 goto out_no_fs_ul;
 294         }
 295         brelse(bh);
 296
 297         if (!(s->s_flags & MS_RDONLY)) {
 298 #ifdef DEBUG
 299                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 300 #endif
 301                 s->s_flags |= MS_RDONLY;
 302         }
 303         s->s_op   = &efs_superblock_operations;
 304         s->s_export_op = &efs_export_ops;
 305         root = iget(s, EFS_ROOTINODE);
 306         s->s_root = d_alloc_root(root);
 307
 308         if (!(s->s_root)) {
 309                 printk(KERN_ERR "EFS: get root inode failed\n");
 310                 iput(root);
 311                 goto out_no_fs;
 312         }
 313
 314         return 0;
 315
 316 out_no_fs_ul:
 317 out_no_fs:
 318         s->s_fs_info = NULL;
 319         kfree(sb);
 320         return -EINVAL;
 321 }
 322
 323 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 324         struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 325
 326         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 327         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 328         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 329                         (sb->group_size - sb->inode_blocks);
 330         buf->f_bfree   = sb->data_free;         /* free data blocks */
 331         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 332         buf->f_files   = sb->total_groups *     /* total inodes */
 333                         sb->inode_blocks *
 334                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 335         buf->f_ffree   = sb->inode_free;        /* free inodes */
 336         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 337         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 338         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 339
 340         return 0;
 341 }
 342