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_CONSTRUCTOR)
  76                 inode_init_once(&ei->vfs_inode);
  77 }
  78
  79 static int init_inodecache(void)
  80 {
  81         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  82                                 sizeof(struct efs_inode_info),
  83                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  84                                 init_once, NULL);
  85         if (efs_inode_cachep == NULL)
  86                 return -ENOMEM;
  87         return 0;
  88 }
  89
  90 static void destroy_inodecache(void)
  91 {
  92         kmem_cache_destroy(efs_inode_cachep);
  93 }
  94
  95 static void efs_put_super(struct super_block *s)
  96 {
  97         kfree(s->s_fs_info);
  98         s->s_fs_info = NULL;
  99 }
 100
 101 static int efs_remount(struct super_block *sb, int *flags, char *data)
 102 {
 103         *flags |= MS_RDONLY;
 104         return 0;
 105 }
 106
 107 static const struct super_operations efs_superblock_operations = {
 108         .alloc_inode    = efs_alloc_inode,
 109         .destroy_inode  = efs_destroy_inode,
 110         .read_inode     = efs_read_inode,
 111         .put_super      = efs_put_super,
 112         .statfs         = efs_statfs,
 113         .remount_fs     = efs_remount,
 114 };
 115
 116 static struct export_operations efs_export_ops = {
 117         .get_parent     = efs_get_parent,
 118 };
 119
 120 static int __init init_efs_fs(void) {
 121         int err;
 122         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 123         err = init_inodecache();
 124         if (err)
 125                 goto out1;
 126         err = register_filesystem(&efs_fs_type);
 127         if (err)
 128                 goto out;
 129         return 0;
 130 out:
 131         destroy_inodecache();
 132 out1:
 133         return err;
 134 }
 135
 136 static void __exit exit_efs_fs(void) {
 137         unregister_filesystem(&efs_fs_type);
 138         destroy_inodecache();
 139 }
 140
 141 module_init(init_efs_fs)
 142 module_exit(exit_efs_fs)
 143
 144 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 145         int             i;
 146         __be32          cs, *ui;
 147         int             csum;
 148         efs_block_t     sblock = 0; /* shuts up gcc */
 149         struct pt_types *pt_entry;
 150         int             pt_type, slice = -1;
 151
 152         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 153                 /*
 154                  * assume that we're dealing with a partition and allow
 155                  * read_super() to try and detect a valid superblock
 156                  * on the next block.
 157                  */
 158                 return 0;
 159         }
 160
 161         ui = ((__be32 *) (vh + 1)) - 1;
 162         for(csum = 0; ui >= ((__be32 *) vh);) {
 163                 cs = *ui--;
 164                 csum += be32_to_cpu(cs);
 165         }
 166         if (csum) {
 167                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 168                 return 0;
 169         }
 170
 171 #ifdef DEBUG
 172         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 173
 174         for(i = 0; i < NVDIR; i++) {
 175                 int     j;
 176                 char    name[VDNAMESIZE+1];
 177
 178                 for(j = 0; j < VDNAMESIZE; j++) {
 179                         name[j] = vh->vh_vd[i].vd_name[j];
 180                 }
 181                 name[j] = (char) 0;
 182
 183                 if (name[0]) {
 184                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 185                                 name,
 186                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 187                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 188                 }
 189         }
 190 #endif
 191
 192         for(i = 0; i < NPARTAB; i++) {
 193                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 194                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 195                         if (pt_type == pt_entry->pt_type) break;
 196                 }
 197 #ifdef DEBUG
 198                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 199                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 200                                 i,
 201                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 202                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 203                                 pt_type,
 204                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 205                 }
 206 #endif
 207                 if (IS_EFS(pt_type)) {
 208                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 209                         slice = i;
 210                 }
 211         }
 212
 213         if (slice == -1) {
 214                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 215 #ifdef DEBUG
 216         } else {
 217                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 218                         slice,
 219                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 220                         sblock);
 221 #endif
 222         }
 223         return sblock;
 224 }
 225
 226 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 227
 228         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 229                 return -1;
 230
 231         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 232         sb->total_blocks = be32_to_cpu(super->fs_size);
 233         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 234         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 235         sb->data_free    = be32_to_cpu(super->fs_tfree);
 236         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 237         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 238         sb->total_groups = be16_to_cpu(super->fs_ncg);
 239
 240         return 0;
 241 }
 242
 243 static int efs_fill_super(struct super_block *s, void *d, int silent)
 244 {
 245         struct efs_sb_info *sb;
 246         struct buffer_head *bh;
 247         struct inode *root;
 248
 249         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 250         if (!sb)
 251                 return -ENOMEM;
 252         s->s_fs_info = sb;
 253
 254         s->s_magic              = EFS_SUPER_MAGIC;
 255         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 256                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 257                         EFS_BLOCKSIZE);
 258                 goto out_no_fs_ul;
 259         }
 260
 261         /* read the vh (volume header) block */
 262         bh = sb_bread(s, 0);
 263
 264         if (!bh) {
 265                 printk(KERN_ERR "EFS: cannot read volume header\n");
 266                 goto out_no_fs_ul;
 267         }
 268
 269         /*
 270          * if this returns zero then we didn't find any partition table.
 271          * this isn't (yet) an error - just assume for the moment that
 272          * the device is valid and go on to search for a superblock.
 273          */
 274         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 275         brelse(bh);
 276
 277         if (sb->fs_start == -1) {
 278                 goto out_no_fs_ul;
 279         }
 280
 281         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 282         if (!bh) {
 283                 printk(KERN_ERR "EFS: cannot read superblock\n");
 284                 goto out_no_fs_ul;
 285         }
 286
 287         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 288 #ifdef DEBUG
 289                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 290 #endif
 291                 brelse(bh);
 292                 goto out_no_fs_ul;
 293         }
 294         brelse(bh);
 295
 296         if (!(s->s_flags & MS_RDONLY)) {
 297 #ifdef DEBUG
 298                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 299 #endif
 300                 s->s_flags |= MS_RDONLY;
 301         }
 302         s->s_op   = &efs_superblock_operations;
 303         s->s_export_op = &efs_export_ops;
 304         root = iget(s, EFS_ROOTINODE);
 305         s->s_root = d_alloc_root(root);
 306
 307         if (!(s->s_root)) {
 308                 printk(KERN_ERR "EFS: get root inode failed\n");
 309                 iput(root);
 310                 goto out_no_fs;
 311         }
 312
 313         return 0;
 314
 315 out_no_fs_ul:
 316 out_no_fs:
 317         s->s_fs_info = NULL;
 318         kfree(sb);
 319         return -EINVAL;
 320 }
 321
 322 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 323         struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 324
 325         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 326         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 327         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 328                         (sb->group_size - sb->inode_blocks);
 329         buf->f_bfree   = sb->data_free;         /* free data blocks */
 330         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 331         buf->f_files   = sb->total_groups *     /* total inodes */
 332                         sb->inode_blocks *
 333                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 334         buf->f_ffree   = sb->inode_free;        /* free inodes */
 335         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 336         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 337         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 338
 339         return 0;
 340 }
 341