linux/fs/qnx4/inode.c
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   1/*
   2 * QNX4 file system, Linux implementation.
   3 *
   4 * Version : 0.2.1
   5 *
   6 * Using parts of the xiafs filesystem.
   7 *
   8 * History :
   9 *
  10 * 01-06-1998 by Richard Frowijn : first release.
  11 * 20-06-1998 by Frank Denis : Linux 2.1.99+ support, boot signature, misc.
  12 * 30-06-1998 by Frank Denis : first step to write inodes.
  13 */
  14
  15#include <linux/module.h>
  16#include <linux/init.h>
  17#include <linux/slab.h>
  18#include <linux/highuid.h>
  19#include <linux/pagemap.h>
  20#include <linux/buffer_head.h>
  21#include <linux/writeback.h>
  22#include <linux/statfs.h>
  23#include "qnx4.h"
  24
  25#define QNX4_VERSION  4
  26#define QNX4_BMNAME   ".bitmap"
  27
  28static const struct super_operations qnx4_sops;
  29
  30static void qnx4_put_super(struct super_block *sb);
  31static struct inode *qnx4_alloc_inode(struct super_block *sb);
  32static void qnx4_destroy_inode(struct inode *inode);
  33static int qnx4_remount(struct super_block *sb, int *flags, char *data);
  34static int qnx4_statfs(struct dentry *, struct kstatfs *);
  35
  36static const struct super_operations qnx4_sops =
  37{
  38        .alloc_inode    = qnx4_alloc_inode,
  39        .destroy_inode  = qnx4_destroy_inode,
  40        .put_super      = qnx4_put_super,
  41        .statfs         = qnx4_statfs,
  42        .remount_fs     = qnx4_remount,
  43};
  44
  45static int qnx4_remount(struct super_block *sb, int *flags, char *data)
  46{
  47        struct qnx4_sb_info *qs;
  48
  49        qs = qnx4_sb(sb);
  50        qs->Version = QNX4_VERSION;
  51        *flags |= MS_RDONLY;
  52        return 0;
  53}
  54
  55static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  56{
  57        unsigned long phys;
  58
  59        QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  60
  61        phys = qnx4_block_map( inode, iblock );
  62        if ( phys ) {
  63                // logical block is before EOF
  64                map_bh(bh, inode->i_sb, phys);
  65        }
  66        return 0;
  67}
  68
  69static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
  70{
  71        u32 size = le32_to_cpu(extent->xtnt_size);
  72        if (*offset < size)
  73                return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
  74        *offset -= size;
  75        return 0;
  76}
  77
  78unsigned long qnx4_block_map( struct inode *inode, long iblock )
  79{
  80        int ix;
  81        long i_xblk;
  82        struct buffer_head *bh = NULL;
  83        struct qnx4_xblk *xblk = NULL;
  84        struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
  85        u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
  86        u32 offset = iblock;
  87        u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
  88
  89        if (block) {
  90                // iblock is in the first extent. This is easy.
  91        } else {
  92                // iblock is beyond first extent. We have to follow the extent chain.
  93                i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
  94                ix = 0;
  95                while ( --nxtnt > 0 ) {
  96                        if ( ix == 0 ) {
  97                                // read next xtnt block.
  98                                bh = sb_bread(inode->i_sb, i_xblk - 1);
  99                                if ( !bh ) {
 100                                        QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 101                                        return -EIO;
 102                                }
 103                                xblk = (struct qnx4_xblk*)bh->b_data;
 104                                if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 105                                        QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 106                                        return -EIO;
 107                                }
 108                        }
 109                        block = try_extent(&xblk->xblk_xtnts[ix], &offset);
 110                        if (block) {
 111                                // got it!
 112                                break;
 113                        }
 114                        if ( ++ix >= xblk->xblk_num_xtnts ) {
 115                                i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 116                                ix = 0;
 117                                brelse( bh );
 118                                bh = NULL;
 119                        }
 120                }
 121                if ( bh )
 122                        brelse( bh );
 123        }
 124
 125        QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 126        return block;
 127}
 128
 129static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 130{
 131        struct super_block *sb = dentry->d_sb;
 132        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 133
 134        buf->f_type    = sb->s_magic;
 135        buf->f_bsize   = sb->s_blocksize;
 136        buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 137        buf->f_bfree   = qnx4_count_free_blocks(sb);
 138        buf->f_bavail  = buf->f_bfree;
 139        buf->f_namelen = QNX4_NAME_MAX;
 140        buf->f_fsid.val[0] = (u32)id;
 141        buf->f_fsid.val[1] = (u32)(id >> 32);
 142
 143        return 0;
 144}
 145
 146/*
 147 * Check the root directory of the filesystem to make sure
 148 * it really _is_ a qnx4 filesystem, and to check the size
 149 * of the directory entry.
 150 */
 151static const char *qnx4_checkroot(struct super_block *sb)
 152{
 153        struct buffer_head *bh;
 154        struct qnx4_inode_entry *rootdir;
 155        int rd, rl;
 156        int i, j;
 157
 158        if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/')
 159                return "no qnx4 filesystem (no root dir).";
 160        QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 161        rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 162        rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 163        for (j = 0; j < rl; j++) {
 164                bh = sb_bread(sb, rd + j);      /* root dir, first block */
 165                if (bh == NULL)
 166                        return "unable to read root entry.";
 167                rootdir = (struct qnx4_inode_entry *) bh->b_data;
 168                for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
 169                        QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 170                        if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
 171                                continue;
 172                        qnx4_sb(sb)->BitMap = kmemdup(rootdir,
 173                                                      sizeof(struct qnx4_inode_entry),
 174                                                      GFP_KERNEL);
 175                        brelse(bh);
 176                        if (!qnx4_sb(sb)->BitMap)
 177                                return "not enough memory for bitmap inode";
 178                        /* keep bitmap inode known */
 179                        return NULL;
 180                }
 181                brelse(bh);
 182        }
 183        return "bitmap file not found.";
 184}
 185
 186static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 187{
 188        struct buffer_head *bh;
 189        struct inode *root;
 190        const char *errmsg;
 191        struct qnx4_sb_info *qs;
 192        int ret = -EINVAL;
 193
 194        qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 195        if (!qs)
 196                return -ENOMEM;
 197        s->s_fs_info = qs;
 198
 199        sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 200
 201        /* Check the superblock signature. Since the qnx4 code is
 202           dangerous, we should leave as quickly as possible
 203           if we don't belong here... */
 204        bh = sb_bread(s, 1);
 205        if (!bh) {
 206                printk(KERN_ERR "qnx4: unable to read the superblock\n");
 207                goto outnobh;
 208        }
 209        if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 210                if (!silent)
 211                        printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 212                goto out;
 213        }
 214        s->s_op = &qnx4_sops;
 215        s->s_magic = QNX4_SUPER_MAGIC;
 216        s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 217        qnx4_sb(s)->sb_buf = bh;
 218        qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 219
 220
 221        /* check before allocating dentries, inodes, .. */
 222        errmsg = qnx4_checkroot(s);
 223        if (errmsg != NULL) {
 224                if (!silent)
 225                        printk(KERN_ERR "qnx4: %s\n", errmsg);
 226                goto out;
 227        }
 228
 229        /* does root not have inode number QNX4_ROOT_INO ?? */
 230        root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 231        if (IS_ERR(root)) {
 232                printk(KERN_ERR "qnx4: get inode failed\n");
 233                ret = PTR_ERR(root);
 234                goto outb;
 235        }
 236
 237        ret = -ENOMEM;
 238        s->s_root = d_make_root(root);
 239        if (s->s_root == NULL)
 240                goto outb;
 241
 242        brelse(bh);
 243        return 0;
 244
 245      outb:
 246        kfree(qs->BitMap);
 247      out:
 248        brelse(bh);
 249      outnobh:
 250        kfree(qs);
 251        s->s_fs_info = NULL;
 252        return ret;
 253}
 254
 255static void qnx4_put_super(struct super_block *sb)
 256{
 257        struct qnx4_sb_info *qs = qnx4_sb(sb);
 258        kfree( qs->BitMap );
 259        kfree( qs );
 260        sb->s_fs_info = NULL;
 261        return;
 262}
 263
 264static int qnx4_readpage(struct file *file, struct page *page)
 265{
 266        return block_read_full_page(page,qnx4_get_block);
 267}
 268
 269static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 270{
 271        return generic_block_bmap(mapping,block,qnx4_get_block);
 272}
 273static const struct address_space_operations qnx4_aops = {
 274        .readpage       = qnx4_readpage,
 275        .bmap           = qnx4_bmap
 276};
 277
 278struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 279{
 280        struct buffer_head *bh;
 281        struct qnx4_inode_entry *raw_inode;
 282        int block;
 283        struct qnx4_inode_entry *qnx4_inode;
 284        struct inode *inode;
 285
 286        inode = iget_locked(sb, ino);
 287        if (!inode)
 288                return ERR_PTR(-ENOMEM);
 289        if (!(inode->i_state & I_NEW))
 290                return inode;
 291
 292        qnx4_inode = qnx4_raw_inode(inode);
 293        inode->i_mode = 0;
 294
 295        QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 296        if (!ino) {
 297                printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 298                                "out of range\n",
 299                       sb->s_id, ino);
 300                iget_failed(inode);
 301                return ERR_PTR(-EIO);
 302        }
 303        block = ino / QNX4_INODES_PER_BLOCK;
 304
 305        if (!(bh = sb_bread(sb, block))) {
 306                printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 307                       "%s\n", sb->s_id);
 308                iget_failed(inode);
 309                return ERR_PTR(-EIO);
 310        }
 311        raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 312            (ino % QNX4_INODES_PER_BLOCK);
 313
 314        inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 315        inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 316        inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 317        set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 318        inode->i_size    = le32_to_cpu(raw_inode->di_size);
 319        inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 320        inode->i_mtime.tv_nsec = 0;
 321        inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 322        inode->i_atime.tv_nsec = 0;
 323        inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 324        inode->i_ctime.tv_nsec = 0;
 325        inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 326
 327        memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 328        if (S_ISREG(inode->i_mode)) {
 329                inode->i_fop = &generic_ro_fops;
 330                inode->i_mapping->a_ops = &qnx4_aops;
 331                qnx4_i(inode)->mmu_private = inode->i_size;
 332        } else if (S_ISDIR(inode->i_mode)) {
 333                inode->i_op = &qnx4_dir_inode_operations;
 334                inode->i_fop = &qnx4_dir_operations;
 335        } else if (S_ISLNK(inode->i_mode)) {
 336                inode->i_op = &page_symlink_inode_operations;
 337                inode->i_mapping->a_ops = &qnx4_aops;
 338                qnx4_i(inode)->mmu_private = inode->i_size;
 339        } else {
 340                printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 341                        ino, sb->s_id);
 342                iget_failed(inode);
 343                brelse(bh);
 344                return ERR_PTR(-EIO);
 345        }
 346        brelse(bh);
 347        unlock_new_inode(inode);
 348        return inode;
 349}
 350
 351static struct kmem_cache *qnx4_inode_cachep;
 352
 353static struct inode *qnx4_alloc_inode(struct super_block *sb)
 354{
 355        struct qnx4_inode_info *ei;
 356        ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 357        if (!ei)
 358                return NULL;
 359        return &ei->vfs_inode;
 360}
 361
 362static void qnx4_i_callback(struct rcu_head *head)
 363{
 364        struct inode *inode = container_of(head, struct inode, i_rcu);
 365        kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 366}
 367
 368static void qnx4_destroy_inode(struct inode *inode)
 369{
 370        call_rcu(&inode->i_rcu, qnx4_i_callback);
 371}
 372
 373static void init_once(void *foo)
 374{
 375        struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 376
 377        inode_init_once(&ei->vfs_inode);
 378}
 379
 380static int init_inodecache(void)
 381{
 382        qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 383                                             sizeof(struct qnx4_inode_info),
 384                                             0, (SLAB_RECLAIM_ACCOUNT|
 385                                                SLAB_MEM_SPREAD),
 386                                             init_once);
 387        if (qnx4_inode_cachep == NULL)
 388                return -ENOMEM;
 389        return 0;
 390}
 391
 392static void destroy_inodecache(void)
 393{
 394        kmem_cache_destroy(qnx4_inode_cachep);
 395}
 396
 397static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 398        int flags, const char *dev_name, void *data)
 399{
 400        return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 401}
 402
 403static struct file_system_type qnx4_fs_type = {
 404        .owner          = THIS_MODULE,
 405        .name           = "qnx4",
 406        .mount          = qnx4_mount,
 407        .kill_sb        = kill_block_super,
 408        .fs_flags       = FS_REQUIRES_DEV,
 409};
 410
 411static int __init init_qnx4_fs(void)
 412{
 413        int err;
 414
 415        err = init_inodecache();
 416        if (err)
 417                return err;
 418
 419        err = register_filesystem(&qnx4_fs_type);
 420        if (err) {
 421                destroy_inodecache();
 422                return err;
 423        }
 424
 425        printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 426        return 0;
 427}
 428
 429static void __exit exit_qnx4_fs(void)
 430{
 431        unregister_filesystem(&qnx4_fs_type);
 432        destroy_inodecache();
 433}
 434
 435module_init(init_qnx4_fs)
 436module_exit(exit_qnx4_fs)
 437MODULE_LICENSE("GPL");
 438
 439
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