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 int efs_get_sb(struct file_system_type *fs_type,
  24         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  25 {
  26         return get_sb_bdev(fs_type, flags, dev_name, data, efs_fill_super, mnt);
  27 }
  28
  29 static struct file_system_type efs_fs_type = {
  30         .owner          = THIS_MODULE,
  31         .name           = "efs",
  32         .get_sb         = efs_get_sb,
  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_destroy_inode(struct inode *inode)
  69 {
  70         kmem_cache_free(efs_inode_cachep, INODE_INFO(inode));
  71 }
  72
  73 static void init_once(void *foo)
  74 {
  75         struct efs_inode_info *ei = (struct efs_inode_info *) foo;
  76
  77         inode_init_once(&ei->vfs_inode);
  78 }
  79
  80 static int init_inodecache(void)
  81 {
  82         efs_inode_cachep = kmem_cache_create("efs_inode_cache",
  83                                 sizeof(struct efs_inode_info),
  84                                 0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
  85                                 init_once);
  86         if (efs_inode_cachep == NULL)
  87                 return -ENOMEM;
  88         return 0;
  89 }
  90
  91 static void destroy_inodecache(void)
  92 {
  93         kmem_cache_destroy(efs_inode_cachep);
  94 }
  95
  96 static void efs_put_super(struct super_block *s)
  97 {
  98         kfree(s->s_fs_info);
  99         s->s_fs_info = NULL;
 100 }
 101
 102 static int efs_remount(struct super_block *sb, int *flags, char *data)
 103 {
 104         *flags |= MS_RDONLY;
 105         return 0;
 106 }
 107
 108 static const struct super_operations efs_superblock_operations = {
 109         .alloc_inode    = efs_alloc_inode,
 110         .destroy_inode  = efs_destroy_inode,
 111         .put_super      = efs_put_super,
 112         .statfs         = efs_statfs,
 113         .remount_fs     = efs_remount,
 114 };
 115
 116 static const struct export_operations efs_export_ops = {
 117         .fh_to_dentry   = efs_fh_to_dentry,
 118         .fh_to_parent   = efs_fh_to_parent,
 119         .get_parent     = efs_get_parent,
 120 };
 121
 122 static int __init init_efs_fs(void) {
 123         int err;
 124         printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 125         err = init_inodecache();
 126         if (err)
 127                 goto out1;
 128         err = register_filesystem(&efs_fs_type);
 129         if (err)
 130                 goto out;
 131         return 0;
 132 out:
 133         destroy_inodecache();
 134 out1:
 135         return err;
 136 }
 137
 138 static void __exit exit_efs_fs(void) {
 139         unregister_filesystem(&efs_fs_type);
 140         destroy_inodecache();
 141 }
 142
 143 module_init(init_efs_fs)
 144 module_exit(exit_efs_fs)
 145
 146 static efs_block_t efs_validate_vh(struct volume_header *vh) {
 147         int             i;
 148         __be32          cs, *ui;
 149         int             csum;
 150         efs_block_t     sblock = 0; /* shuts up gcc */
 151         struct pt_types *pt_entry;
 152         int             pt_type, slice = -1;
 153
 154         if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 155                 /*
 156                  * assume that we're dealing with a partition and allow
 157                  * read_super() to try and detect a valid superblock
 158                  * on the next block.
 159                  */
 160                 return 0;
 161         }
 162
 163         ui = ((__be32 *) (vh + 1)) - 1;
 164         for(csum = 0; ui >= ((__be32 *) vh);) {
 165                 cs = *ui--;
 166                 csum += be32_to_cpu(cs);
 167         }
 168         if (csum) {
 169                 printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 170                 return 0;
 171         }
 172
 173 #ifdef DEBUG
 174         printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 175
 176         for(i = 0; i < NVDIR; i++) {
 177                 int     j;
 178                 char    name[VDNAMESIZE+1];
 179
 180                 for(j = 0; j < VDNAMESIZE; j++) {
 181                         name[j] = vh->vh_vd[i].vd_name[j];
 182                 }
 183                 name[j] = (char) 0;
 184
 185                 if (name[0]) {
 186                         printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 187                                 name,
 188                                 (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 189                                 (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 190                 }
 191         }
 192 #endif
 193
 194         for(i = 0; i < NPARTAB; i++) {
 195                 pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 196                 for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 197                         if (pt_type == pt_entry->pt_type) break;
 198                 }
 199 #ifdef DEBUG
 200                 if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 201                         printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 202                                 i,
 203                                 (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 204                                 (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 205                                 pt_type,
 206                                 (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 207                 }
 208 #endif
 209                 if (IS_EFS(pt_type)) {
 210                         sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 211                         slice = i;
 212                 }
 213         }
 214
 215         if (slice == -1) {
 216                 printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 217 #ifdef DEBUG
 218         } else {
 219                 printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 220                         slice,
 221                         (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 222                         sblock);
 223 #endif
 224         }
 225         return sblock;
 226 }
 227
 228 static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 229
 230         if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 231                 return -1;
 232
 233         sb->fs_magic     = be32_to_cpu(super->fs_magic);
 234         sb->total_blocks = be32_to_cpu(super->fs_size);
 235         sb->first_block  = be32_to_cpu(super->fs_firstcg);
 236         sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 237         sb->data_free    = be32_to_cpu(super->fs_tfree);
 238         sb->inode_free   = be32_to_cpu(super->fs_tinode);
 239         sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 240         sb->total_groups = be16_to_cpu(super->fs_ncg);
 241
 242         return 0;
 243 }
 244
 245 static int efs_fill_super(struct super_block *s, void *d, int silent)
 246 {
 247         struct efs_sb_info *sb;
 248         struct buffer_head *bh;
 249         struct inode *root;
 250         int ret = -EINVAL;
 251
 252         sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 253         if (!sb)
 254                 return -ENOMEM;
 255         s->s_fs_info = sb;
 256
 257         s->s_magic              = EFS_SUPER_MAGIC;
 258         if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 259                 printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 260                         EFS_BLOCKSIZE);
 261                 goto out_no_fs_ul;
 262         }
 263
 264         /* read the vh (volume header) block */
 265         bh = sb_bread(s, 0);
 266
 267         if (!bh) {
 268                 printk(KERN_ERR "EFS: cannot read volume header\n");
 269                 goto out_no_fs_ul;
 270         }
 271
 272         /*
 273          * if this returns zero then we didn't find any partition table.
 274          * this isn't (yet) an error - just assume for the moment that
 275          * the device is valid and go on to search for a superblock.
 276          */
 277         sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 278         brelse(bh);
 279
 280         if (sb->fs_start == -1) {
 281                 goto out_no_fs_ul;
 282         }
 283
 284         bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 285         if (!bh) {
 286                 printk(KERN_ERR "EFS: cannot read superblock\n");
 287                 goto out_no_fs_ul;
 288         }
 289
 290         if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 291 #ifdef DEBUG
 292                 printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 293 #endif
 294                 brelse(bh);
 295                 goto out_no_fs_ul;
 296         }
 297         brelse(bh);
 298
 299         if (!(s->s_flags & MS_RDONLY)) {
 300 #ifdef DEBUG
 301                 printk(KERN_INFO "EFS: forcing read-only mode\n");
 302 #endif
 303                 s->s_flags |= MS_RDONLY;
 304         }
 305         s->s_op   = &efs_superblock_operations;
 306         s->s_export_op = &efs_export_ops;
 307         root = efs_iget(s, EFS_ROOTINODE);
 308         if (IS_ERR(root)) {
 309                 printk(KERN_ERR "EFS: get root inode failed\n");
 310                 ret = PTR_ERR(root);
 311                 goto out_no_fs;
 312         }
 313
 314         s->s_root = d_alloc_root(root);
 315         if (!(s->s_root)) {
 316                 printk(KERN_ERR "EFS: get root dentry failed\n");
 317                 iput(root);
 318                 ret = -ENOMEM;
 319                 goto out_no_fs;
 320         }
 321
 322         return 0;
 323
 324 out_no_fs_ul:
 325 out_no_fs:
 326         s->s_fs_info = NULL;
 327         kfree(sb);
 328         return ret;
 329 }
 330
 331 static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 332         struct efs_sb_info *sb = SUPER_INFO(dentry->d_sb);
 333
 334         buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 335         buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 336         buf->f_blocks  = sb->total_groups *     /* total data blocks */
 337                         (sb->group_size - sb->inode_blocks);
 338         buf->f_bfree   = sb->data_free;         /* free data blocks */
 339         buf->f_bavail  = sb->data_free;         /* free blocks for non-root */
 340         buf->f_files   = sb->total_groups *     /* total inodes */
 341                         sb->inode_blocks *
 342                         (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 343         buf->f_ffree   = sb->inode_free;        /* free inodes */
 344         buf->f_fsid.val[0] = (sb->fs_magic >> 16) & 0xffff; /* fs ID */
 345         buf->f_fsid.val[1] =  sb->fs_magic        & 0xffff; /* fs ID */
 346         buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 347
 348         return 0;
 349 }
 350