linux/fs/efs/super.c
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   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
  20static int efs_statfs(struct dentry *dentry, struct kstatfs *buf);
  21static int efs_fill_super(struct super_block *s, void *d, int silent);
  22
  23static 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
  29static 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
  37static 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
  57static struct kmem_cache * efs_inode_cachep;
  58
  59static 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
  68static 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
  74static void efs_destroy_inode(struct inode *inode)
  75{
  76        call_rcu(&inode->i_rcu, efs_i_callback);
  77}
  78
  79static 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
  86static 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
  97static void destroy_inodecache(void)
  98{
  99        kmem_cache_destroy(efs_inode_cachep);
 100}
 101
 102static void efs_put_super(struct super_block *s)
 103{
 104        kfree(s->s_fs_info);
 105        s->s_fs_info = NULL;
 106}
 107
 108static int efs_remount(struct super_block *sb, int *flags, char *data)
 109{
 110        *flags |= MS_RDONLY;
 111        return 0;
 112}
 113
 114static const struct super_operations efs_superblock_operations = {
 115        .alloc_inode    = efs_alloc_inode,
 116        .destroy_inode  = efs_destroy_inode,
 117        .put_super      = efs_put_super,
 118        .statfs         = efs_statfs,
 119        .remount_fs     = efs_remount,
 120};
 121
 122static const struct export_operations efs_export_ops = {
 123        .fh_to_dentry   = efs_fh_to_dentry,
 124        .fh_to_parent   = efs_fh_to_parent,
 125        .get_parent     = efs_get_parent,
 126};
 127
 128static int __init init_efs_fs(void) {
 129        int err;
 130        printk("EFS: "EFS_VERSION" - http://aeschi.ch.eu.org/efs/\n");
 131        err = init_inodecache();
 132        if (err)
 133                goto out1;
 134        err = register_filesystem(&efs_fs_type);
 135        if (err)
 136                goto out;
 137        return 0;
 138out:
 139        destroy_inodecache();
 140out1:
 141        return err;
 142}
 143
 144static void __exit exit_efs_fs(void) {
 145        unregister_filesystem(&efs_fs_type);
 146        destroy_inodecache();
 147}
 148
 149module_init(init_efs_fs)
 150module_exit(exit_efs_fs)
 151
 152static efs_block_t efs_validate_vh(struct volume_header *vh) {
 153        int             i;
 154        __be32          cs, *ui;
 155        int             csum;
 156        efs_block_t     sblock = 0; /* shuts up gcc */
 157        struct pt_types *pt_entry;
 158        int             pt_type, slice = -1;
 159
 160        if (be32_to_cpu(vh->vh_magic) != VHMAGIC) {
 161                /*
 162                 * assume that we're dealing with a partition and allow
 163                 * read_super() to try and detect a valid superblock
 164                 * on the next block.
 165                 */
 166                return 0;
 167        }
 168
 169        ui = ((__be32 *) (vh + 1)) - 1;
 170        for(csum = 0; ui >= ((__be32 *) vh);) {
 171                cs = *ui--;
 172                csum += be32_to_cpu(cs);
 173        }
 174        if (csum) {
 175                printk(KERN_INFO "EFS: SGI disklabel: checksum bad, label corrupted\n");
 176                return 0;
 177        }
 178
 179#ifdef DEBUG
 180        printk(KERN_DEBUG "EFS: bf: \"%16s\"\n", vh->vh_bootfile);
 181
 182        for(i = 0; i < NVDIR; i++) {
 183                int     j;
 184                char    name[VDNAMESIZE+1];
 185
 186                for(j = 0; j < VDNAMESIZE; j++) {
 187                        name[j] = vh->vh_vd[i].vd_name[j];
 188                }
 189                name[j] = (char) 0;
 190
 191                if (name[0]) {
 192                        printk(KERN_DEBUG "EFS: vh: %8s block: 0x%08x size: 0x%08x\n",
 193                                name,
 194                                (int) be32_to_cpu(vh->vh_vd[i].vd_lbn),
 195                                (int) be32_to_cpu(vh->vh_vd[i].vd_nbytes));
 196                }
 197        }
 198#endif
 199
 200        for(i = 0; i < NPARTAB; i++) {
 201                pt_type = (int) be32_to_cpu(vh->vh_pt[i].pt_type);
 202                for(pt_entry = sgi_pt_types; pt_entry->pt_name; pt_entry++) {
 203                        if (pt_type == pt_entry->pt_type) break;
 204                }
 205#ifdef DEBUG
 206                if (be32_to_cpu(vh->vh_pt[i].pt_nblks)) {
 207                        printk(KERN_DEBUG "EFS: pt %2d: start: %08d size: %08d type: 0x%02x (%s)\n",
 208                                i,
 209                                (int) be32_to_cpu(vh->vh_pt[i].pt_firstlbn),
 210                                (int) be32_to_cpu(vh->vh_pt[i].pt_nblks),
 211                                pt_type,
 212                                (pt_entry->pt_name) ? pt_entry->pt_name : "unknown");
 213                }
 214#endif
 215                if (IS_EFS(pt_type)) {
 216                        sblock = be32_to_cpu(vh->vh_pt[i].pt_firstlbn);
 217                        slice = i;
 218                }
 219        }
 220
 221        if (slice == -1) {
 222                printk(KERN_NOTICE "EFS: partition table contained no EFS partitions\n");
 223#ifdef DEBUG
 224        } else {
 225                printk(KERN_INFO "EFS: using slice %d (type %s, offset 0x%x)\n",
 226                        slice,
 227                        (pt_entry->pt_name) ? pt_entry->pt_name : "unknown",
 228                        sblock);
 229#endif
 230        }
 231        return sblock;
 232}
 233
 234static int efs_validate_super(struct efs_sb_info *sb, struct efs_super *super) {
 235
 236        if (!IS_EFS_MAGIC(be32_to_cpu(super->fs_magic)))
 237                return -1;
 238
 239        sb->fs_magic     = be32_to_cpu(super->fs_magic);
 240        sb->total_blocks = be32_to_cpu(super->fs_size);
 241        sb->first_block  = be32_to_cpu(super->fs_firstcg);
 242        sb->group_size   = be32_to_cpu(super->fs_cgfsize);
 243        sb->data_free    = be32_to_cpu(super->fs_tfree);
 244        sb->inode_free   = be32_to_cpu(super->fs_tinode);
 245        sb->inode_blocks = be16_to_cpu(super->fs_cgisize);
 246        sb->total_groups = be16_to_cpu(super->fs_ncg);
 247    
 248        return 0;    
 249}
 250
 251static int efs_fill_super(struct super_block *s, void *d, int silent)
 252{
 253        struct efs_sb_info *sb;
 254        struct buffer_head *bh;
 255        struct inode *root;
 256        int ret = -EINVAL;
 257
 258        sb = kzalloc(sizeof(struct efs_sb_info), GFP_KERNEL);
 259        if (!sb)
 260                return -ENOMEM;
 261        s->s_fs_info = sb;
 262 
 263        s->s_magic              = EFS_SUPER_MAGIC;
 264        if (!sb_set_blocksize(s, EFS_BLOCKSIZE)) {
 265                printk(KERN_ERR "EFS: device does not support %d byte blocks\n",
 266                        EFS_BLOCKSIZE);
 267                goto out_no_fs_ul;
 268        }
 269  
 270        /* read the vh (volume header) block */
 271        bh = sb_bread(s, 0);
 272
 273        if (!bh) {
 274                printk(KERN_ERR "EFS: cannot read volume header\n");
 275                goto out_no_fs_ul;
 276        }
 277
 278        /*
 279         * if this returns zero then we didn't find any partition table.
 280         * this isn't (yet) an error - just assume for the moment that
 281         * the device is valid and go on to search for a superblock.
 282         */
 283        sb->fs_start = efs_validate_vh((struct volume_header *) bh->b_data);
 284        brelse(bh);
 285
 286        if (sb->fs_start == -1) {
 287                goto out_no_fs_ul;
 288        }
 289
 290        bh = sb_bread(s, sb->fs_start + EFS_SUPER);
 291        if (!bh) {
 292                printk(KERN_ERR "EFS: cannot read superblock\n");
 293                goto out_no_fs_ul;
 294        }
 295                
 296        if (efs_validate_super(sb, (struct efs_super *) bh->b_data)) {
 297#ifdef DEBUG
 298                printk(KERN_WARNING "EFS: invalid superblock at block %u\n", sb->fs_start + EFS_SUPER);
 299#endif
 300                brelse(bh);
 301                goto out_no_fs_ul;
 302        }
 303        brelse(bh);
 304
 305        if (!(s->s_flags & MS_RDONLY)) {
 306#ifdef DEBUG
 307                printk(KERN_INFO "EFS: forcing read-only mode\n");
 308#endif
 309                s->s_flags |= MS_RDONLY;
 310        }
 311        s->s_op   = &efs_superblock_operations;
 312        s->s_export_op = &efs_export_ops;
 313        root = efs_iget(s, EFS_ROOTINODE);
 314        if (IS_ERR(root)) {
 315                printk(KERN_ERR "EFS: get root inode failed\n");
 316                ret = PTR_ERR(root);
 317                goto out_no_fs;
 318        }
 319
 320        s->s_root = d_make_root(root);
 321        if (!(s->s_root)) {
 322                printk(KERN_ERR "EFS: get root dentry failed\n");
 323                ret = -ENOMEM;
 324                goto out_no_fs;
 325        }
 326
 327        return 0;
 328
 329out_no_fs_ul:
 330out_no_fs:
 331        s->s_fs_info = NULL;
 332        kfree(sb);
 333        return ret;
 334}
 335
 336static int efs_statfs(struct dentry *dentry, struct kstatfs *buf) {
 337        struct super_block *sb = dentry->d_sb;
 338        struct efs_sb_info *sbi = SUPER_INFO(sb);
 339        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 340
 341        buf->f_type    = EFS_SUPER_MAGIC;       /* efs magic number */
 342        buf->f_bsize   = EFS_BLOCKSIZE;         /* blocksize */
 343        buf->f_blocks  = sbi->total_groups *    /* total data blocks */
 344                        (sbi->group_size - sbi->inode_blocks);
 345        buf->f_bfree   = sbi->data_free;        /* free data blocks */
 346        buf->f_bavail  = sbi->data_free;        /* free blocks for non-root */
 347        buf->f_files   = sbi->total_groups *    /* total inodes */
 348                        sbi->inode_blocks *
 349                        (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
 350        buf->f_ffree   = sbi->inode_free;       /* free inodes */
 351        buf->f_fsid.val[0] = (u32)id;
 352        buf->f_fsid.val[1] = (u32)(id >> 32);
 353        buf->f_namelen = EFS_MAXNAMELEN;        /* max filename length */
 354
 355        return 0;
 356}
 357
 358
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