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