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 struct file_system_type efs_fs_type = {
  30         .owner          = THIS_MODULE,
  31         .name           = "efs",
  32         .mount          = efs_mount,
  33         .kill_sb        = kill_block_super,
  34         .fs_flags       = FS_REQUIRES_DEV,
  35 };
  36 MODULE_ALIAS_FS("efs");
  37
  38 static struct pt_types sgi_pt_types[] = {
  39         {0x00,          "SGI vh"},
  40         {0x01,          "SGI trkrepl"},
  41         {0x02,          "SGI secrepl"},
  42         {0x03,          "SGI raw"},
  43         {0x04,          "SGI bsd"},
  44         {SGI_SYSV,      "SGI sysv"},
  45         {0x06,          "SGI vol"},
  46         {SGI_EFS,       "SGI efs"},
  47         {0x08,          "SGI lv"},
  48         {0x09,          "SGI rlv"},
  49         {0x0A,          "SGI xfs"},
  50         {0x0B,          "SGI xfslog"},
  51         {0x0C,          "SGI xlv"},
  52         {0x82,          "Linux swap"},
  53         {0x83,          "Linux native"},
  54         {0,             NULL}
  55 };
  56
  57
  58 static struct kmem_cache * efs_inode_cachep;
  59
  60 static struct inode *efs_alloc_inode(struct super_block *sb)
  61 {
  62         struct efs_inode_info *ei;
  63         ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  64         if (!ei)
  65                 return NULL;
  66         return &ei->vfs_inode;
  67 }
  68
  69 static void efs_i_callback(struct rcu_head *head)
  70 {
  71         struct inode *inode = container_of(head, struct inode, i_rcu);
  72         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  73 }
  74
  75 static void efs_destroy_inode(struct inode *inode)
  76 {
  77         call_rcu(&inode->i_rcu, efs_i_callback);
  78 }
  79
  80 static void init_once(void *foo)
  81 {
  82         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  83
  84         inode_init_once(&ei->vfs_inode);
  85 }
  86
  87 static int init_inodecache(void)
  88 {
  89         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  90                                 sizeof(struct efs_inode_info),
  91                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  92                                 init_once);
  93         if (efs_inode_cachep == NULL)
  94                 return -ENOMEM;
  95         return 0;
  96 }
  97
  98 static void destroy_inodecache(void)
  99 {
 100         /*
 101          * Make sure all delayed rcu free inodes are flushed before we
 102          * destroy cache.
 103          */
 104         rcu_barrier();
 105         kmem_cache_destroy(efs_inode_cachep);
 106 }
 107
 108 static void efs_put_super(struct super_block *s)
 109 {
 110         kfree(s->s_fs_info);
 111         s->s_fs_info = NULL;
 112 }
 113
 114 static int efs_remount(struct super_block *sb, int *flags, char *data)
 115 {
 116         *flags |= MS_RDONLY;
 117         return 0;
 118 }
 119
 120 static const struct super_operations efs_superblock_operations = {
 121         .alloc_inode    = efs_alloc_inode,
 122         .destroy_inode  = efs_destroy_inode,
 123         .put_super      = efs_put_super,
 124         .statfs         = efs_statfs,
 125         .remount_fs     = efs_remount,
 126 };
 127
 128 static const struct export_operations efs_export_ops = {
 129         .fh_to_dentry   = efs_fh_to_dentry,
 130         .fh_to_parent   = efs_fh_to_parent,
 131         .get_parent     = efs_get_parent,
 132 };
 133
 134 static int __init init_efs_fs(void) {
 135         int err;
 136         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 137         err = init_inodecache();
 138         if (err)
 139                 goto out1;
 140         err = register_filesystem(&efs_fs_type);
 141         if (err)
 142                 goto out;
 143         return 0;
 144 out:
 145         destroy_inodecache();
 146 out1:
 147         return err;
 148 }
 149
 150 static void __exit exit_efs_fs(void) {
 151         unregister_filesystem(&efs_fs_type);
 152         destroy_inodecache();
 153 }
 154
 155 module_init(init_efs_fs)
 156 module_exit(exit_efs_fs)
 157
 158 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 159         int             i;
 160         __be32          cs, *ui;
 161         int             csum;
 162         efs_block_t     sblock = 0; /* shuts up gcc */
 163         struct pt_types *pt_entry;
 164         int             pt_type, slice = -1;
 165
 166         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 167                 /*
 168                  * assume that we're dealing with a partition and allow
 169                  * read_super() to try and detect a valid superblock
 170                  * on the next block.
 171                  */
 172                 return 0;
 173         }
 174
 175         ui = ((__be32 *) (vh + 1)) - 1;
 176         for(csum = 0; ui >= ((__be32 *) vh);) {
 177                 cs = *ui--;
 178                 csum += be32_to_cpu(cs);
 179         }
 180         if (csum) {
 181                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 182                 return 0;
 183         }
 184
 185 #ifdef DEBUG
 186         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 187
 188         for(i = 0; i < NVDIR; i++) {
 189                 int     j;
 190                 char    name[VDNAMESIZE+1];
 191
 192                 for(j = 0; j < VDNAMESIZE; j++) {
 193                         name[j] = vh->vh_vd[i].vd_name[j];
 194                 }
 195                 name[j] = (char) 0;
 196
 197                 if (name[0]) {
 198                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 199                                 name,
 200                                 (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                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 214                                 i,
 215                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 216                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 217                                 pt_type,
 218                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 219                 }
 220 #endif
 221                 if (IS_EFS(pt_type)) {
 222                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 223                         slice = i;
 224                 }
 225         }
 226
 227         if (slice == -1) {
 228                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 229 #ifdef DEBUG
 230         } else {
 231                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 232                         slice,
 233                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 234                         sblock);
 235 #endif
 236         }
 237         return sblock;
 238 }
 239
 240 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 241
 242         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 243                 return -1;
 244
 245         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 246         sb->total_blocks = be32_to_cpu(super->fs_size);
 247         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 248         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 249         sb->data_free    = be32_to_cpu(super->fs_tfree);
 250         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 251         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 252         sb->total_groups = be16_to_cpu(super->fs_ncg);
 253
 254         return 0;
 255 }
 256
 257 static int efs_fill_super(struct super_block *s, void *d, int silent)
 258 {
 259         struct efs_sb_info *sb;
 260         struct buffer_head *bh;
 261         struct inode *root;
 262         int ret = -EINVAL;
 263
 264         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 265         if (!sb)
 266                 return -ENOMEM;
 267         s->s_fs_info = sb;
 268
 269         s->s_magic              = EFS_SUPER_MAGIC;
 270         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 271                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 272                         EFS_BLOCKSIZE);
 273                 goto out_no_fs_ul;
 274         }
 275
 276         /* read the vh (volume header) block */
 277         bh = sb_bread(s, 0);
 278
 279         if (!bh) {
 280                 printk(KERN_ERR "EFS: cannot read volume header\n");
 281                 goto out_no_fs_ul;
 282         }
 283
 284         /*
 285          * if this returns zero then we didn't find any partition table.
 286          * this isn't (yet) an error - just assume for the moment that
 287          * the device is valid and go on to search for a superblock.
 288          */
 289         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 290         brelse(bh);
 291
 292         if (sb->fs_start == -1) {
 293                 goto out_no_fs_ul;
 294         }
 295
 296         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 297         if (!bh) {
 298                 printk(KERN_ERR "EFS: cannot read superblock\n");
 299                 goto out_no_fs_ul;
 300         }
 301
 302         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 303 #ifdef DEBUG
 304                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 305 #endif
 306                 brelse(bh);
 307                 goto out_no_fs_ul;
 308         }
 309         brelse(bh);
 310
 311         if (!(s->s_flags & MS_RDONLY)) {
 312 #ifdef DEBUG
 313                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 314 #endif
 315                 s->s_flags |= MS_RDONLY;
 316         }
 317         s->s_op   = &efs_superblock_operations;
 318         s->s_export_op = &efs_export_ops;
 319         root = efs_iget(s, EFS_ROOTINODE);
 320         if (IS_ERR(root)) {
 321                 printk(KERN_ERR "EFS: get root inode failed\n");
 322                 ret = PTR_ERR(root);
 323                 goto out_no_fs;
 324         }
 325
 326         s->s_root = d_make_root(root);
 327         if (!(s->s_root)) {
 328                 printk(KERN_ERR "EFS: get root dentry failed\n");
 329                 ret = -ENOMEM;
 330                 goto out_no_fs;
 331         }
 332
 333         return 0;
 334
 335 out_no_fs_ul:
 336 out_no_fs:
 337         s->s_fs_info = NULL;
 338         kfree(sb);
 339         return ret;
 340 }
 341
 342 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 343         struct super_block *sb = dentry->d_sb;
 344         struct efs_sb_info *sbi = SUPER_INFO(sb);
 345         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 346
 347         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 348         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 349         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 350                         (sbi->group_size - sbi->inode_blocks);
 351         buf->f_bfree   = sbi->data_free;        /* free data blocks */
 352         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 353         buf->f_files   = sbi->total_groups *    /* total inodes */
 354                         sbi->inode_blocks *
 355                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 356         buf->f_ffree   = sbi->inode_free;       /* free inodes */
 357         buf->f_fsid.val[0] = (u32)id;
 358         buf->f_fsid.val[1] = (u32)(id >> 32);
 359         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 360
 361         return 0;
 362 }
 363