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 struct inode *qnx4_alloc_inode(struct super_block *sb);
  31static void qnx4_destroy_inode(struct inode *inode);
  32static int qnx4_remount(struct super_block *sb, int *flags, char *data);
  33static int qnx4_statfs(struct dentry *, struct kstatfs *);
  34
  35static const struct super_operations qnx4_sops =
  36{
  37        .alloc_inode    = qnx4_alloc_inode,
  38        .destroy_inode  = qnx4_destroy_inode,
  39        .statfs         = qnx4_statfs,
  40        .remount_fs     = qnx4_remount,
  41};
  42
  43static int qnx4_remount(struct super_block *sb, int *flags, char *data)
  44{
  45        struct qnx4_sb_info *qs;
  46
  47        sync_filesystem(sb);
  48        qs = qnx4_sb(sb);
  49        qs->Version = QNX4_VERSION;
  50        *flags |= MS_RDONLY;
  51        return 0;
  52}
  53
  54static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  55{
  56        unsigned long phys;
  57
  58        QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  59
  60        phys = qnx4_block_map( inode, iblock );
  61        if ( phys ) {
  62                // logical block is before EOF
  63                map_bh(bh, inode->i_sb, phys);
  64        }
  65        return 0;
  66}
  67
  68static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
  69{
  70        u32 size = le32_to_cpu(extent->xtnt_size);
  71        if (*offset < size)
  72                return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
  73        *offset -= size;
  74        return 0;
  75}
  76
  77unsigned long qnx4_block_map( struct inode *inode, long iblock )
  78{
  79        int ix;
  80        long i_xblk;
  81        struct buffer_head *bh = NULL;
  82        struct qnx4_xblk *xblk = NULL;
  83        struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
  84        u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
  85        u32 offset = iblock;
  86        u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
  87
  88        if (block) {
  89                // iblock is in the first extent. This is easy.
  90        } else {
  91                // iblock is beyond first extent. We have to follow the extent chain.
  92                i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
  93                ix = 0;
  94                while ( --nxtnt > 0 ) {
  95                        if ( ix == 0 ) {
  96                                // read next xtnt block.
  97                                bh = sb_bread(inode->i_sb, i_xblk - 1);
  98                                if ( !bh ) {
  99                                        QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 100                                        return -EIO;
 101                                }
 102                                xblk = (struct qnx4_xblk*)bh->b_data;
 103                                if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 104                                        QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 105                                        return -EIO;
 106                                }
 107                        }
 108                        block = try_extent(&xblk->xblk_xtnts[ix], &offset);
 109                        if (block) {
 110                                // got it!
 111                                break;
 112                        }
 113                        if ( ++ix >= xblk->xblk_num_xtnts ) {
 114                                i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 115                                ix = 0;
 116                                brelse( bh );
 117                                bh = NULL;
 118                        }
 119                }
 120                if ( bh )
 121                        brelse( bh );
 122        }
 123
 124        QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 125        return block;
 126}
 127
 128static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 129{
 130        struct super_block *sb = dentry->d_sb;
 131        u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 132
 133        buf->f_type    = sb->s_magic;
 134        buf->f_bsize   = sb->s_blocksize;
 135        buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 136        buf->f_bfree   = qnx4_count_free_blocks(sb);
 137        buf->f_bavail  = buf->f_bfree;
 138        buf->f_namelen = QNX4_NAME_MAX;
 139        buf->f_fsid.val[0] = (u32)id;
 140        buf->f_fsid.val[1] = (u32)(id >> 32);
 141
 142        return 0;
 143}
 144
 145/*
 146 * Check the root directory of the filesystem to make sure
 147 * it really _is_ a qnx4 filesystem, and to check the size
 148 * of the directory entry.
 149 */
 150static const char *qnx4_checkroot(struct super_block *sb,
 151                                  struct qnx4_super_block *s)
 152{
 153        struct buffer_head *bh;
 154        struct qnx4_inode_entry *rootdir;
 155        int rd, rl;
 156        int i, j;
 157
 158        if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
 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(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
 162        rl = le32_to_cpu(s->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
 193        qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 194        if (!qs)
 195                return -ENOMEM;
 196        s->s_fs_info = qs;
 197
 198        sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 199
 200        s->s_op = &qnx4_sops;
 201        s->s_magic = QNX4_SUPER_MAGIC;
 202        s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 203
 204        /* Check the superblock signature. Since the qnx4 code is
 205           dangerous, we should leave as quickly as possible
 206           if we don't belong here... */
 207        bh = sb_bread(s, 1);
 208        if (!bh) {
 209                printk(KERN_ERR "qnx4: unable to read the superblock\n");
 210                return -EINVAL;
 211        }
 212
 213        /* check before allocating dentries, inodes, .. */
 214        errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
 215        brelse(bh);
 216        if (errmsg != NULL) {
 217                if (!silent)
 218                        printk(KERN_ERR "qnx4: %s\n", errmsg);
 219                return -EINVAL;
 220        }
 221
 222        /* does root not have inode number QNX4_ROOT_INO ?? */
 223        root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 224        if (IS_ERR(root)) {
 225                printk(KERN_ERR "qnx4: get inode failed\n");
 226                return PTR_ERR(root);
 227        }
 228
 229        s->s_root = d_make_root(root);
 230        if (s->s_root == NULL)
 231                return -ENOMEM;
 232
 233        return 0;
 234}
 235
 236static void qnx4_kill_sb(struct super_block *sb)
 237{
 238        struct qnx4_sb_info *qs = qnx4_sb(sb);
 239        kill_block_super(sb);
 240        if (qs) {
 241                kfree(qs->BitMap);
 242                kfree(qs);
 243        }
 244}
 245
 246static int qnx4_readpage(struct file *file, struct page *page)
 247{
 248        return block_read_full_page(page,qnx4_get_block);
 249}
 250
 251static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 252{
 253        return generic_block_bmap(mapping,block,qnx4_get_block);
 254}
 255static const struct address_space_operations qnx4_aops = {
 256        .readpage       = qnx4_readpage,
 257        .bmap           = qnx4_bmap
 258};
 259
 260struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 261{
 262        struct buffer_head *bh;
 263        struct qnx4_inode_entry *raw_inode;
 264        int block;
 265        struct qnx4_inode_entry *qnx4_inode;
 266        struct inode *inode;
 267
 268        inode = iget_locked(sb, ino);
 269        if (!inode)
 270                return ERR_PTR(-ENOMEM);
 271        if (!(inode->i_state & I_NEW))
 272                return inode;
 273
 274        qnx4_inode = qnx4_raw_inode(inode);
 275        inode->i_mode = 0;
 276
 277        QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 278        if (!ino) {
 279                printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 280                                "out of range\n",
 281                       sb->s_id, ino);
 282                iget_failed(inode);
 283                return ERR_PTR(-EIO);
 284        }
 285        block = ino / QNX4_INODES_PER_BLOCK;
 286
 287        if (!(bh = sb_bread(sb, block))) {
 288                printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 289                       "%s\n", sb->s_id);
 290                iget_failed(inode);
 291                return ERR_PTR(-EIO);
 292        }
 293        raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 294            (ino % QNX4_INODES_PER_BLOCK);
 295
 296        inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 297        i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
 298        i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
 299        set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 300        inode->i_size    = le32_to_cpu(raw_inode->di_size);
 301        inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 302        inode->i_mtime.tv_nsec = 0;
 303        inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 304        inode->i_atime.tv_nsec = 0;
 305        inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 306        inode->i_ctime.tv_nsec = 0;
 307        inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 308
 309        memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 310        if (S_ISREG(inode->i_mode)) {
 311                inode->i_fop = &generic_ro_fops;
 312                inode->i_mapping->a_ops = &qnx4_aops;
 313                qnx4_i(inode)->mmu_private = inode->i_size;
 314        } else if (S_ISDIR(inode->i_mode)) {
 315                inode->i_op = &qnx4_dir_inode_operations;
 316                inode->i_fop = &qnx4_dir_operations;
 317        } else if (S_ISLNK(inode->i_mode)) {
 318                inode->i_op = &page_symlink_inode_operations;
 319                inode->i_mapping->a_ops = &qnx4_aops;
 320                qnx4_i(inode)->mmu_private = inode->i_size;
 321        } else {
 322                printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 323                        ino, sb->s_id);
 324                iget_failed(inode);
 325                brelse(bh);
 326                return ERR_PTR(-EIO);
 327        }
 328        brelse(bh);
 329        unlock_new_inode(inode);
 330        return inode;
 331}
 332
 333static struct kmem_cache *qnx4_inode_cachep;
 334
 335static struct inode *qnx4_alloc_inode(struct super_block *sb)
 336{
 337        struct qnx4_inode_info *ei;
 338        ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 339        if (!ei)
 340                return NULL;
 341        return &ei->vfs_inode;
 342}
 343
 344static void qnx4_i_callback(struct rcu_head *head)
 345{
 346        struct inode *inode = container_of(head, struct inode, i_rcu);
 347        kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 348}
 349
 350static void qnx4_destroy_inode(struct inode *inode)
 351{
 352        call_rcu(&inode->i_rcu, qnx4_i_callback);
 353}
 354
 355static void init_once(void *foo)
 356{
 357        struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 358
 359        inode_init_once(&ei->vfs_inode);
 360}
 361
 362static int init_inodecache(void)
 363{
 364        qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 365                                             sizeof(struct qnx4_inode_info),
 366                                             0, (SLAB_RECLAIM_ACCOUNT|
 367                                                SLAB_MEM_SPREAD),
 368                                             init_once);
 369        if (qnx4_inode_cachep == NULL)
 370                return -ENOMEM;
 371        return 0;
 372}
 373
 374static void destroy_inodecache(void)
 375{
 376        /*
 377         * Make sure all delayed rcu free inodes are flushed before we
 378         * destroy cache.
 379         */
 380        rcu_barrier();
 381        kmem_cache_destroy(qnx4_inode_cachep);
 382}
 383
 384static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 385        int flags, const char *dev_name, void *data)
 386{
 387        return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 388}
 389
 390static struct file_system_type qnx4_fs_type = {
 391        .owner          = THIS_MODULE,
 392        .name           = "qnx4",
 393        .mount          = qnx4_mount,
 394        .kill_sb        = qnx4_kill_sb,
 395        .fs_flags       = FS_REQUIRES_DEV,
 396};
 397MODULE_ALIAS_FS("qnx4");
 398
 399static int __init init_qnx4_fs(void)
 400{
 401        int err;
 402
 403        err = init_inodecache();
 404        if (err)
 405                return err;
 406
 407        err = register_filesystem(&qnx4_fs_type);
 408        if (err) {
 409                destroy_inodecache();
 410                return err;
 411        }
 412
 413        printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 414        return 0;
 415}
 416
 417static void __exit exit_qnx4_fs(void)
 418{
 419        unregister_filesystem(&qnx4_fs_type);
 420        destroy_inodecache();
 421}
 422
 423module_init(init_qnx4_fs)
 424module_exit(exit_qnx4_fs)
 425MODULE_LICENSE("GPL");
 426
 427
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