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         INIT_LIST_HEAD(&inode->i_dentry);
  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         kmem_cache_destroy(efs_inode_cachep);
 101 }
 102
 103 static void efs_put_super(struct super_block *s)
 104 {
 105         kfree(s->s_fs_info);
 106         s->s_fs_info = NULL;
 107 }
 108
 109 static int efs_remount(struct super_block *sb, int *flags, char *data)
 110 {
 111         *flags |= MS_RDONLY;
 112         return 0;
 113 }
 114
 115 static const struct super_operations efs_superblock_operations = {
 116         .alloc_inode    = efs_alloc_inode,
 117         .destroy_inode  = efs_destroy_inode,
 118         .put_super      = efs_put_super,
 119         .statfs         = efs_statfs,
 120         .remount_fs     = efs_remount,
 121 };
 122
 123 static const struct export_operations efs_export_ops = {
 124         .fh_to_dentry   = efs_fh_to_dentry,
 125         .fh_to_parent   = efs_fh_to_parent,
 126         .get_parent     = efs_get_parent,
 127 };
 128
 129 static int __init init_efs_fs(void) {
 130         int err;
 131         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 132         err = init_inodecache();
 133         if (err)
 134                 goto out1;
 135         err = register_filesystem(&efs_fs_type);
 136         if (err)
 137                 goto out;
 138         return 0;
 139 out:
 140         destroy_inodecache();
 141 out1:
 142         return err;
 143 }
 144
 145 static void __exit exit_efs_fs(void) {
 146         unregister_filesystem(&efs_fs_type);
 147         destroy_inodecache();
 148 }
 149
 150 module_init(init_efs_fs)
 151 module_exit(exit_efs_fs)
 152
 153 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 154         int             i;
 155         __be32          cs, *ui;
 156         int             csum;
 157         efs_block_t     sblock = 0; /* shuts up gcc */
 158         struct pt_types *pt_entry;
 159         int             pt_type, slice = -1;
 160
 161         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 162                 /*
 163                  * assume that we're dealing with a partition and allow
 164                  * read_super() to try and detect a valid superblock
 165                  * on the next block.
 166                  */
 167                 return 0;
 168         }
 169
 170         ui = ((__be32 *) (vh + 1)) - 1;
 171         for(csum = 0; ui >= ((__be32 *) vh);) {
 172                 cs = *ui--;
 173                 csum += be32_to_cpu(cs);
 174         }
 175         if (csum) {
 176                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 177                 return 0;
 178         }
 179
 180 #ifdef DEBUG
 181         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 182
 183         for(i = 0; i < NVDIR; i++) {
 184                 int     j;
 185                 char    name[VDNAMESIZE+1];
 186
 187                 for(j = 0; j < VDNAMESIZE; j++) {
 188                         name[j] = vh->vh_vd[i].vd_name[j];
 189                 }
 190                 name[j] = (char) 0;
 191
 192                 if (name[0]) {
 193                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 194                                 name,
 195                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 196                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 197                 }
 198         }
 199 #endif
 200
 201         for(i = 0; i < NPARTAB; i++) {
 202                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 203                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 204                         if (pt_type == pt_entry->pt_type) break;
 205                 }
 206 #ifdef DEBUG
 207                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 208                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 209                                 i,
 210                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 211                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 212                                 pt_type,
 213                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 214                 }
 215 #endif
 216                 if (IS_EFS(pt_type)) {
 217                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 218                         slice = i;
 219                 }
 220         }
 221
 222         if (slice == -1) {
 223                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 224 #ifdef DEBUG
 225         } else {
 226                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 227                         slice,
 228                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 229                         sblock);
 230 #endif
 231         }
 232         return sblock;
 233 }
 234
 235 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 236
 237         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 238                 return -1;
 239
 240         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 241         sb->total_blocks = be32_to_cpu(super->fs_size);
 242         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 243         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 244         sb->data_free    = be32_to_cpu(super->fs_tfree);
 245         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 246         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 247         sb->total_groups = be16_to_cpu(super->fs_ncg);
 248
 249         return 0;
 250 }
 251
 252 static int efs_fill_super(struct super_block *s, void *d, int silent)
 253 {
 254         struct efs_sb_info *sb;
 255         struct buffer_head *bh;
 256         struct inode *root;
 257         int ret = -EINVAL;
 258
 259         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 260         if (!sb)
 261                 return -ENOMEM;
 262         s->s_fs_info = sb;
 263
 264         s->s_magic              = EFS_SUPER_MAGIC;
 265         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 266                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 267                         EFS_BLOCKSIZE);
 268                 goto out_no_fs_ul;
 269         }
 270
 271         /* read the vh (volume header) block */
 272         bh = sb_bread(s, 0);
 273
 274         if (!bh) {
 275                 printk(KERN_ERR "EFS: cannot read volume header\n");
 276                 goto out_no_fs_ul;
 277         }
 278
 279         /*
 280          * if this returns zero then we didn't find any partition table.
 281          * this isn't (yet) an error - just assume for the moment that
 282          * the device is valid and go on to search for a superblock.
 283          */
 284         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 285         brelse(bh);
 286
 287         if (sb->fs_start == -1) {
 288                 goto out_no_fs_ul;
 289         }
 290
 291         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 292         if (!bh) {
 293                 printk(KERN_ERR "EFS: cannot read superblock\n");
 294                 goto out_no_fs_ul;
 295         }
 296
 297         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 298 #ifdef DEBUG
 299                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 300 #endif
 301                 brelse(bh);
 302                 goto out_no_fs_ul;
 303         }
 304         brelse(bh);
 305
 306         if (!(s->s_flags & MS_RDONLY)) {
 307 #ifdef DEBUG
 308                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 309 #endif
 310                 s->s_flags |= MS_RDONLY;
 311         }
 312         s->s_op   = &efs_superblock_operations;
 313         s->s_export_op = &efs_export_ops;
 314         root = efs_iget(s, EFS_ROOTINODE);
 315         if (IS_ERR(root)) {
 316                 printk(KERN_ERR "EFS: get root inode failed\n");
 317                 ret = PTR_ERR(root);
 318                 goto out_no_fs;
 319         }
 320
 321         s->s_root = d_alloc_root(root);
 322         if (!(s->s_root)) {
 323                 printk(KERN_ERR "EFS: get root dentry failed\n");
 324                 iput(root);
 325                 ret = -ENOMEM;
 326                 goto out_no_fs;
 327         }
 328
 329         return 0;
 330
 331 out_no_fs_ul:
 332 out_no_fs:
 333         s->s_fs_info = NULL;
 334         kfree(sb);
 335         return ret;
 336 }
 337
 338 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 339         struct super_block *sb = dentry->d_sb;
 340         struct efs_sb_info *sbi = SUPER_INFO(sb);
 341         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 342
 343         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 344         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 345         buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 346                         (sbi->group_size - sbi->inode_blocks);
 347         buf->f_bfree   = sbi->data_free;        /* free data blocks */
 348         buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 349         buf->f_files   = sbi->total_groups *    /* total inodes */
 350                         sbi->inode_blocks *
 351                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 352         buf->f_ffree   = sbi->inode_free;       /* free inodes */
 353         buf->f_fsid.val[0] = (u32)id;
 354         buf->f_fsid.val[1] = (u32)(id >> 32);
 355         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 356
 357         return 0;
 358 }
 359