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        /*
 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
 107static void efs_put_super(struct super_block *s)
 108{
 109        kfree(s->s_fs_info);
 110        s->s_fs_info = NULL;
 111}
 112
 113static int efs_remount(struct super_block *sb, int *flags, char *data)
 114{
 115        *flags |= MS_RDONLY;
 116        return 0;
 117}
 118
 119static 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
 127static 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
 133static 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;
 143out:
 144        destroy_inodecache();
 145out1:
 146        return err;
 147}
 148
 149static void __exit exit_efs_fs(void) {
 150        unregister_filesystem(&efs_fs_type);
 151        destroy_inodecache();
 152}
 153
 154module_init(init_efs_fs)
 155module_exit(exit_efs_fs)
 156
 157static 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
 239static 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
 256static 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
 334out_no_fs_ul:
 335out_no_fs:
 336        s->s_fs_info = NULL;
 337        kfree(sb);
 338        return ret;
 339}
 340
 341static 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
 363
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