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
  37 static struct pt_types sgi_pt_types[] = {
  38         {0x00,          "SGI vh"},
  39         {0x01,          "SGI trkrepl"},
  40         {0x02,          "SGI secrepl"},
  41         {0x03,          "SGI raw"},
  42         {0x04,          "SGI bsd"},
  43         {SGI_SYSV,      "SGI sysv"},
  44         {0x06,          "SGI vol"},
  45         {SGI_EFS,       "SGI efs"},
  46         {0x08,          "SGI lv"},
  47         {0x09,          "SGI rlv"},
  48         {0x0A,          "SGI xfs"},
  49         {0x0B,          "SGI xfslog"},
  50         {0x0C,          "SGI xlv"},
  51         {0x82,          "Linux swap"},
  52         {0x83,          "Linux native"},
  53         {0,             NULL}
  54 };
  55
  56
  57 static struct kmem_cache * efs_inode_cachep;
  58
  59 static struct inode *efs_alloc_inode(struct super_block *sb)
  60 {
  61         struct efs_inode_info *ei;
  62         ei = (struct efs_inode_info *)kmem_cache_alloc(efs_inode_cachep, GFP_KERNEL);
  63         if (!ei)
  64                 return NULL;
  65         return &ei->vfs_inode;
  66 }
  67
  68 static void efs_i_callback(struct rcu_head *head)
  69 {
  70         struct inode *inode = container_of(head, struct inode, i_rcu);
  71         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  72 }
  73
  74 static void efs_destroy_inode(struct inode *inode)
  75 {
  76         call_rcu(&inode->i_rcu, efs_i_callback);
  77 }
  78
  79 static void init_once(void *foo)
  80 {
  81         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  82
  83         inode_init_once(&ei->vfs_inode);
  84 }
  85
  86 static int init_inodecache(void)
  87 {
  88         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  89                                 sizeof(struct efs_inode_info),
  90                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  91                                 init_once);
  92         if (efs_inode_cachep == NULL)
  93                 return -ENOMEM;
  94         return 0;
  95 }
  96
  97 static void destroy_inodecache(void)
  98 {
  99         /*
 100          * Make sure all delayed rcu free inodes are flushed before we
 101          * destroy cache.
 102          */
 103         rcu_barrier();
 104         kmem_cache_destroy(efs_inode_cachep);
 105 }
 106
 107 static void efs_put_super(struct super_block *s)
 108 {
 109         kfree(s->s_fs_info);
 110         s->s_fs_info = NULL;
 111 }
 112
 113 static int efs_remount(struct super_block *sb, int *flags, char *data)
 114 {
 115         *flags |= MS_RDONLY;
 116         return 0;
 117 }
 118
 119 static const struct super_operations efs_superblock_operations = {
 120         .alloc_inode    = efs_alloc_inode,
 121         .destroy_inode  = efs_destroy_inode,
 122         .put_super      = efs_put_super,
 123         .statfs         = efs_statfs,
 124         .remount_fs     = efs_remount,
 125 };
 126
 127 static const struct export_operations efs_export_ops = {
 128         .fh_to_dentry   = efs_fh_to_dentry,
 129         .fh_to_parent   = efs_fh_to_parent,
 130         .get_parent     = efs_get_parent,
 131 };
 132
 133 static int __init init_efs_fs(void) {
 134         int err;
 135         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 136         err = init_inodecache();
 137         if (err)
 138                 goto out1;
 139         err = register_filesystem(&efs_fs_type);
 140         if (err)
 141                 goto out;
 142         return 0;
 143 out:
 144         destroy_inodecache();
 145 out1:
 146         return err;
 147 }
 148
 149 static void __exit exit_efs_fs(void) {
 150         unregister_filesystem(&efs_fs_type);
 151         destroy_inodecache();
 152 }
 153
 154 module_init(init_efs_fs)
 155 module_exit(exit_efs_fs)
 156
 157 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 158         int             i;
 159         __be32          cs, *ui;
 160         int             csum;
 161         efs_block_t     sblock = 0; /* shuts up gcc */
 162         struct pt_types *pt_entry;
 163         int             pt_type, slice = -1;
 164
 165         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 166                 /*
 167                  * assume that we're dealing with a partition and allow
 168                  * read_super() to try and detect a valid superblock
 169                  * on the next block.
 170                  */
 171                 return 0;
 172         }
 173
 174         ui = ((__be32 *) (vh + 1)) - 1;
 175         for(csum = 0; ui >= ((__be32 *) vh);) {
 176                 cs = *ui--;
 177                 csum += be32_to_cpu(cs);
 178         }
 179         if (csum) {
 180                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 181                 return 0;
 182         }
 183
 184 #ifdef DEBUG
 185         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 186
 187         for(i = 0; i < NVDIR; i++) {
 188                 int     j;
 189                 char    name[VDNAMESIZE+1];
 190
 191                 for(j = 0; j < VDNAMESIZE; j++) {
 192                         name[j] = vh->vh_vd[i].vd_name[j];
 193                 }
 194                 name[j] = (char) 0;
 195
 196                 if (name[0]) {
 197                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 198                                 name,
 199                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 200                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 201                 }
 202         }
 203 #endif
 204
 205         for(i = 0; i < NPARTAB; i++) {
 206                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 207                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 208                         if (pt_type == pt_entry->pt_type) break;
 209                 }
 210 #ifdef DEBUG
 211                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 212                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 213                                 i,
 214                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 215                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 216                                 pt_type,
 217                                 (pt_entry->pt_name) ? 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                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 228 #ifdef DEBUG
 229         } else {
 230                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 231                         slice,
 232                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 233                         sblock);
 234 #endif
 235         }
 236         return sblock;
 237 }
 238
 239 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 240
 241         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 242                 return -1;
 243
 244         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 245         sb->total_blocks = be32_to_cpu(super->fs_size);
 246         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 247         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 248         sb->data_free    = be32_to_cpu(super->fs_tfree);
 249         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 250         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 251         sb->total_groups = be16_to_cpu(super->fs_ncg);
 252
 253         return 0;
 254 }
 255
 256 static int efs_fill_super(struct super_block *s, void *d, int silent)
 257 {
 258         struct efs_sb_info *sb;
 259         struct buffer_head *bh;
 260         struct inode *root;
 261         int ret = -EINVAL;
 262
 263         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 264         if (!sb)
 265                 return -ENOMEM;
 266         s->s_fs_info = sb;
 267
 268         s->s_magic              = EFS_SUPER_MAGIC;
 269         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 270                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 271                         EFS_BLOCKSIZE);
 272                 goto out_no_fs_ul;
 273         }
 274
 275         /* read the vh (volume header) block */
 276         bh = sb_bread(s, 0);
 277
 278         if (!bh) {
 279                 printk(KERN_ERR "EFS: cannot read volume header\n");
 280                 goto out_no_fs_ul;
 281         }
 282
 283         /*
 284          * if this returns zero then we didn't find any partition table.
 285          * this isn't (yet) an error - just assume for the moment that
 286          * the device is valid and go on to search for a superblock.
 287          */
 288         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 289         brelse(bh);
 290
 291         if (sb->fs_start == -1) {
 292                 goto out_no_fs_ul;
 293         }
 294
 295         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 296         if (!bh) {
 297                 printk(KERN_ERR "EFS: cannot read superblock\n");
 298                 goto out_no_fs_ul;
 299         }
 300
 301         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 302 #ifdef DEBUG
 303                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 304 #endif
 305                 brelse(bh);
 306                 goto out_no_fs_ul;
 307         }
 308         brelse(bh);
 309
 310         if (!(s->s_flags & MS_RDONLY)) {
 311 #ifdef DEBUG
 312                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 313 #endif
 314                 s->s_flags |= MS_RDONLY;
 315         }
 316         s->s_op   = &efs_superblock_operations;
 317         s->s_export_op = &efs_export_ops;
 318         root = efs_iget(s, EFS_ROOTINODE);
 319         if (IS_ERR(root)) {
 320                 printk(KERN_ERR "EFS: get root inode failed\n");
 321                 ret = PTR_ERR(root);
 322                 goto out_no_fs;
 323         }
 324
 325         s->s_root = d_make_root(root);
 326         if (!(s->s_root)) {
 327                 printk(KERN_ERR "EFS: get root dentry failed\n");
 328                 ret = -ENOMEM;
 329                 goto out_no_fs;
 330         }
 331
 332         return 0;
 333
 334 out_no_fs_ul:
 335 out_no_fs:
 336         s->s_fs_info = NULL;
 337         kfree(sb);
 338         return ret;
 339 }
 340
 341 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 342         struct super_block *sb = dentry->d_sb;
 343         struct efs_sb_info *sbi = SUPER_INFO(sb);
 344         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 345
 346         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 347         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 348         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 349                         (sbi->group_size - sbi->inode_blocks);
 350         buf->f_bfree   = sbi->data_free;        /* free data blocks */
 351         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 352         buf->f_files   = sbi->total_groups *    /* total inodes */
 353                         sbi->inode_blocks *
 354                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 355         buf->f_ffree   = sbi->inode_free;       /* free inodes */
 356         buf->f_fsid.val[0] = (u32)id;
 357         buf->f_fsid.val[1] = (u32)(id >> 32);
 358         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 359
 360         return 0;
 361 }
 362