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/exportfs.h>
  12 #include <linux/slab.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/vfs.h>
  15
  16 #include "efs.h"
  17 #include <linux/efs_vh.h>
  18 #include <linux/efs_fs_sb.h>
  19
  20 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  21 static int efs_fill_super(struct super_block *s, void *d, int silent);
  22
  23 static struct dentry *efs_mount(struct file_system_type *fs_type,
  24         int flags, const char *dev_name, void *data)
  25 {
  26         return mount_bdev(fs_type, flags, dev_name, data, efs_fill_super);
  27 }
  28
  29 static void efs_kill_sb(struct super_block *s)
  30 {
  31         struct efs_sb_info *sbi = SUPER_INFO(s);
  32         kill_block_super(s);
  33         kfree(sbi);
  34 }
  35
  36 static struct file_system_type efs_fs_type = {
  37         .owner          = THIS_MODULE,
  38         .name           = "efs",
  39         .mount          = efs_mount,
  40         .kill_sb        = efs_kill_sb,
  41         .fs_flags       = FS_REQUIRES_DEV,
  42 };
  43 MODULE_ALIAS_FS("efs");
  44
  45 static struct pt_types sgi_pt_types[] = {
  46         {0x00,          "SGI vh"},
  47         {0x01,          "SGI trkrepl"},
  48         {0x02,          "SGI secrepl"},
  49         {0x03,          "SGI raw"},
  50         {0x04,          "SGI bsd"},
  51         {SGI_SYSV,      "SGI sysv"},
  52         {0x06,          "SGI vol"},
  53         {SGI_EFS,       "SGI efs"},
  54         {0x08,          "SGI lv"},
  55         {0x09,          "SGI rlv"},
  56         {0x0A,          "SGI xfs"},
  57         {0x0B,          "SGI xfslog"},
  58         {0x0C,          "SGI xlv"},
  59         {0x82,          "Linux swap"},
  60         {0x83,          "Linux native"},
  61         {0,             NULL}
  62 };
  63
  64
  65 static struct kmem_cache * efs_inode_cachep;
  66
  67 static struct inode *efs_alloc_inode(struct super_block *sb)
  68 {
  69         struct efs_inode_info *ei;
  70         ei = kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  71         if (!ei)
  72                 return NULL;
  73         return &ei->vfs_inode;
  74 }
  75
  76 static void efs_i_callback(struct rcu_head *head)
  77 {
  78         struct inode *inode = container_of(head, struct inode, i_rcu);
  79         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  80 }
  81
  82 static void efs_destroy_inode(struct inode *inode)
  83 {
  84         call_rcu(&inode->i_rcu, efs_i_callback);
  85 }
  86
  87 static void init_once(void *foo)
  88 {
  89         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  90
  91         inode_init_once(&ei->vfs_inode);
  92 }
  93
  94 static int __init init_inodecache(void)
  95 {
  96         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  97                                 sizeof(struct efs_inode_info), 0,
  98                                 SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
  99                                 SLAB_ACCOUNT, init_once);
 100         if (efs_inode_cachep == NULL)
 101                 return -ENOMEM;
 102         return 0;
 103 }
 104
 105 static void destroy_inodecache(void)
 106 {
 107         /*
 108          * Make sure all delayed rcu free inodes are flushed before we
 109          * destroy cache.
 110          */
 111         rcu_barrier();
 112         kmem_cache_destroy(efs_inode_cachep);
 113 }
 114
 115 static int efs_remount(struct super_block *sb, int *flags, char *data)
 116 {
 117         sync_filesystem(sb);
 118         *flags |= MS_RDONLY;
 119         return 0;
 120 }
 121
 122 static const struct super_operations efs_superblock_operations = {
 123         .alloc_inode    = efs_alloc_inode,
 124         .destroy_inode  = efs_destroy_inode,
 125         .statfs         = efs_statfs,
 126         .remount_fs     = efs_remount,
 127 };
 128
 129 static const struct export_operations efs_export_ops = {
 130         .fh_to_dentry   = efs_fh_to_dentry,
 131         .fh_to_parent   = efs_fh_to_parent,
 132         .get_parent     = efs_get_parent,
 133 };
 134
 135 static int __init init_efs_fs(void) {
 136         int err;
 137         pr_info(EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 138         err = init_inodecache();
 139         if (err)
 140                 goto out1;
 141         err = register_filesystem(&efs_fs_type);
 142         if (err)
 143                 goto out;
 144         return 0;
 145 out:
 146         destroy_inodecache();
 147 out1:
 148         return err;
 149 }
 150
 151 static void __exit exit_efs_fs(void) {
 152         unregister_filesystem(&efs_fs_type);
 153         destroy_inodecache();
 154 }
 155
 156 module_init(init_efs_fs)
 157 module_exit(exit_efs_fs)
 158
 159 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 160         int             i;
 161         __be32          cs, *ui;
 162         int             csum;
 163         efs_block_t     sblock = 0; /* shuts up gcc */
 164         struct pt_types *pt_entry;
 165         int             pt_type, slice = -1;
 166
 167         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 168                 /*
 169                  * assume that we're dealing with a partition and allow
 170                  * read_super() to try and detect a valid superblock
 171                  * on the next block.
 172                  */
 173                 return 0;
 174         }
 175
 176         ui = ((__be32 *) (vh + 1)) - 1;
 177         for(csum = 0; ui >= ((__be32 *) vh);) {
 178                 cs = *ui--;
 179                 csum += be32_to_cpu(cs);
 180         }
 181         if (csum) {
 182                 pr_warn("SGI disklabel: checksum bad, label corrupted\n");
 183                 return 0;
 184         }
 185
 186 #ifdef DEBUG
 187         pr_debug("bf: \"%16s\"\n", vh->vh_bootfile);
 188
 189         for(i = 0; i < NVDIR; i++) {
 190                 int     j;
 191                 char    name[VDNAMESIZE+1];
 192
 193                 for(j = 0; j < VDNAMESIZE; j++) {
 194                         name[j] = vh->vh_vd[i].vd_name[j];
 195                 }
 196                 name[j] = (char) 0;
 197
 198                 if (name[0]) {
 199                         pr_debug("vh: %8s block: 0x%08x size: 0x%08x\n",
 200                                 name, (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 201                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 202                 }
 203         }
 204 #endif
 205
 206         for(i = 0; i < NPARTAB; i++) {
 207                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 208                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 209                         if (pt_type == pt_entry->pt_type) break;
 210                 }
 211 #ifdef DEBUG
 212                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 213                         pr_debug("pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 214                                  i, (int)be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 215                                  (int)be32_to_cpu(vh->vh_pt[i].pt_nblks),
 216                                  pt_type, (pt_entry->pt_name) ?
 217                                  pt_entry->pt_name : "unknown");
 218                 }
 219 #endif
 220                 if (IS_EFS(pt_type)) {
 221                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 222                         slice = i;
 223                 }
 224         }
 225
 226         if (slice == -1) {
 227                 pr_notice("partition table contained no EFS partitions\n");
 228 #ifdef DEBUG
 229         } else {
 230                 pr_info("using slice %d (type %s, offset 0x%x)\n", slice,
 231                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 232                         sblock);
 233 #endif
 234         }
 235         return sblock;
 236 }
 237
 238 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 239
 240         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 241                 return -1;
 242
 243         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 244         sb->total_blocks = be32_to_cpu(super->fs_size);
 245         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 246         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 247         sb->data_free    = be32_to_cpu(super->fs_tfree);
 248         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 249         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 250         sb->total_groups = be16_to_cpu(super->fs_ncg);
 251
 252         return 0;
 253 }
 254
 255 static int efs_fill_super(struct super_block *s, void *d, int silent)
 256 {
 257         struct efs_sb_info *sb;
 258         struct buffer_head *bh;
 259         struct inode *root;
 260
 261         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 262         if (!sb)
 263                 return -ENOMEM;
 264         s->s_fs_info = sb;
 265
 266         s->s_magic              = EFS_SUPER_MAGIC;
 267         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 268                 pr_err("device does not support %d byte blocks\n",
 269                         EFS_BLOCKSIZE);
 270                 return -EINVAL;
 271         }
 272
 273         /* read the vh (volume header) block */
 274         bh = sb_bread(s, 0);
 275
 276         if (!bh) {
 277                 pr_err("cannot read volume header\n");
 278                 return -EINVAL;
 279         }
 280
 281         /*
 282          * if this returns zero then we didn't find any partition table.
 283          * this isn't (yet) an error - just assume for the moment that
 284          * the device is valid and go on to search for a superblock.
 285          */
 286         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 287         brelse(bh);
 288
 289         if (sb->fs_start == -1) {
 290                 return -EINVAL;
 291         }
 292
 293         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 294         if (!bh) {
 295                 pr_err("cannot read superblock\n");
 296                 return -EINVAL;
 297         }
 298
 299         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 300 #ifdef DEBUG
 301                 pr_warn("invalid superblock at block %u\n",
 302                         sb->fs_start + EFS_SUPER);
 303 #endif
 304                 brelse(bh);
 305                 return -EINVAL;
 306         }
 307         brelse(bh);
 308
 309         if (!(s->s_flags & MS_RDONLY)) {
 310 #ifdef DEBUG
 311                 pr_info("forcing read-only mode\n");
 312 #endif
 313                 s->s_flags |= MS_RDONLY;
 314         }
 315         s->s_op   = &efs_superblock_operations;
 316         s->s_export_op = &efs_export_ops;
 317         root = efs_iget(s, EFS_ROOTINODE);
 318         if (IS_ERR(root)) {
 319                 pr_err("get root inode failed\n");
 320                 return PTR_ERR(root);
 321         }
 322
 323         s->s_root = d_make_root(root);
 324         if (!(s->s_root)) {
 325                 pr_err("get root dentry failed\n");
 326                 return -ENOMEM;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 333         struct super_block *sb = dentry->d_sb;
 334         struct efs_sb_info *sbi = SUPER_INFO(sb);
 335         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 336
 337         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 338         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 339         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 340                         (sbi->group_size - sbi->inode_blocks);
 341         buf->f_bfree   = sbi->data_free;        /* free data blocks */
 342         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 343         buf->f_files   = sbi->total_groups *    /* total inodes */
 344                         sbi->inode_blocks *
 345                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 346         buf->f_ffree   = sbi->inode_free;       /* free inodes */
 347         buf->f_fsid.val[0] = (u32)id;
 348         buf->f_fsid.val[1] = (u32)(id >> 32);
 349         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 350
 351         return 0;
 352 }
 353