fs/qnx4/inode.c

   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/smp_lock.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/buffer_head.h>
  22 #include <linux/writeback.h>
  23 #include <linux/statfs.h>
  24 #include "qnx4.h"
  25
  26 #define QNX4_VERSION  4
  27 #define QNX4_BMNAME   ".bitmap"
  28
  29 static const struct super_operations qnx4_sops;
  30
  31 static void qnx4_put_super(struct super_block *sb);
  32 static struct inode *qnx4_alloc_inode(struct super_block *sb);
  33 static void qnx4_destroy_inode(struct inode *inode);
  34 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
  35 static int qnx4_statfs(struct dentry *, struct kstatfs *);
  36
  37 static const struct super_operations qnx4_sops =
  38 {
  39         .alloc_inode    = qnx4_alloc_inode,
  40         .destroy_inode  = qnx4_destroy_inode,
  41         .put_super      = qnx4_put_super,
  42         .statfs         = qnx4_statfs,
  43         .remount_fs     = qnx4_remount,
  44 };
  45
  46 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
  47 {
  48         struct qnx4_sb_info *qs;
  49
  50         qs = qnx4_sb(sb);
  51         qs->Version = QNX4_VERSION;
  52         *flags |= MS_RDONLY;
  53         return 0;
  54 }
  55
  56 static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
  57                                        int create)
  58 {
  59         struct buffer_head *result = NULL;
  60
  61         if ( nr >= 0 )
  62                 nr = qnx4_block_map( inode, nr );
  63         if (nr) {
  64                 result = sb_getblk(inode->i_sb, nr);
  65                 return result;
  66         }
  67         return NULL;
  68 }
  69
  70 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
  71 {
  72         struct buffer_head *bh;
  73
  74         bh = qnx4_getblk(inode, block, create);
  75         if (!bh || buffer_uptodate(bh)) {
  76                 return bh;
  77         }
  78         ll_rw_block(READ, 1, &bh);
  79         wait_on_buffer(bh);
  80         if (buffer_uptodate(bh)) {
  81                 return bh;
  82         }
  83         brelse(bh);
  84
  85         return NULL;
  86 }
  87
  88 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  89 {
  90         unsigned long phys;
  91
  92         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  93
  94         phys = qnx4_block_map( inode, iblock );
  95         if ( phys ) {
  96                 // logical block is before EOF
  97                 map_bh(bh, inode->i_sb, phys);
  98         }
  99         return 0;
 100 }
 101
 102 unsigned long qnx4_block_map( struct inode *inode, long iblock )
 103 {
 104         int ix;
 105         long offset, i_xblk;
 106         unsigned long block = 0;
 107         struct buffer_head *bh = NULL;
 108         struct qnx4_xblk *xblk = NULL;
 109         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
 110         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
 111
 112         if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
 113                 // iblock is in the first extent. This is easy.
 114                 block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
 115         } else {
 116                 // iblock is beyond first extent. We have to follow the extent chain.
 117                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
 118                 offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
 119                 ix = 0;
 120                 while ( --nxtnt > 0 ) {
 121                         if ( ix == 0 ) {
 122                                 // read next xtnt block.
 123                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 124                                 if ( !bh ) {
 125                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 126                                         return -EIO;
 127                                 }
 128                                 xblk = (struct qnx4_xblk*)bh->b_data;
 129                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 130                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 131                                         return -EIO;
 132                                 }
 133                         }
 134                         if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
 135                                 // got it!
 136                                 block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
 137                                 break;
 138                         }
 139                         offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
 140                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 141                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 142                                 ix = 0;
 143                                 brelse( bh );
 144                                 bh = NULL;
 145                         }
 146                 }
 147                 if ( bh )
 148                         brelse( bh );
 149         }
 150
 151         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 152         return block;
 153 }
 154
 155 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 156 {
 157         struct super_block *sb = dentry->d_sb;
 158         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 159
 160         lock_kernel();
 161
 162         buf->f_type    = sb->s_magic;
 163         buf->f_bsize   = sb->s_blocksize;
 164         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 165         buf->f_bfree   = qnx4_count_free_blocks(sb);
 166         buf->f_bavail  = buf->f_bfree;
 167         buf->f_namelen = QNX4_NAME_MAX;
 168         buf->f_fsid.val[0] = (u32)id;
 169         buf->f_fsid.val[1] = (u32)(id >> 32);
 170
 171         unlock_kernel();
 172
 173         return 0;
 174 }
 175
 176 /*
 177  * Check the root directory of the filesystem to make sure
 178  * it really _is_ a qnx4 filesystem, and to check the size
 179  * of the directory entry.
 180  */
 181 static const char *qnx4_checkroot(struct super_block *sb)
 182 {
 183         struct buffer_head *bh;
 184         struct qnx4_inode_entry *rootdir;
 185         int rd, rl;
 186         int i, j;
 187         int found = 0;
 188
 189         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
 190                 return "no qnx4 filesystem (no root dir).";
 191         } else {
 192                 QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 193                 rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 194                 rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 195                 for (j = 0; j < rl; j++) {
 196                         bh = sb_bread(sb, rd + j);      /* root dir, first block */
 197                         if (bh == NULL) {
 198                                 return "unable to read root entry.";
 199                         }
 200                         for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
 201                                 rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
 202                                 if (rootdir->di_fname != NULL) {
 203                                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 204                                         if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
 205                                                 found = 1;
 206                                                 qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
 207                                                 if (!qnx4_sb(sb)->BitMap) {
 208                                                         brelse (bh);
 209                                                         return "not enough memory for bitmap inode";
 210                                                 }
 211                                                 memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */
 212                                                 break;
 213                                         }
 214                                 }
 215                         }
 216                         brelse(bh);
 217                         if (found != 0) {
 218                                 break;
 219                         }
 220                 }
 221                 if (found == 0) {
 222                         return "bitmap file not found.";
 223                 }
 224         }
 225         return NULL;
 226 }
 227
 228 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 229 {
 230         struct buffer_head *bh;
 231         struct inode *root;
 232         const char *errmsg;
 233         struct qnx4_sb_info *qs;
 234         int ret = -EINVAL;
 235
 236         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 237         if (!qs)
 238                 return -ENOMEM;
 239         s->s_fs_info = qs;
 240
 241         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 242
 243         /* Check the superblock signature. Since the qnx4 code is
 244            dangerous, we should leave as quickly as possible
 245            if we don't belong here... */
 246         bh = sb_bread(s, 1);
 247         if (!bh) {
 248                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 249                 goto outnobh;
 250         }
 251         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 252                 if (!silent)
 253                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 254                 goto out;
 255         }
 256         s->s_op = &qnx4_sops;
 257         s->s_magic = QNX4_SUPER_MAGIC;
 258         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 259         qnx4_sb(s)->sb_buf = bh;
 260         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 261
 262
 263         /* check before allocating dentries, inodes, .. */
 264         errmsg = qnx4_checkroot(s);
 265         if (errmsg != NULL) {
 266                 if (!silent)
 267                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 268                 goto out;
 269         }
 270
 271         /* does root not have inode number QNX4_ROOT_INO ?? */
 272         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 273         if (IS_ERR(root)) {
 274                 printk(KERN_ERR "qnx4: get inode failed\n");
 275                 ret = PTR_ERR(root);
 276                 goto out;
 277         }
 278
 279         ret = -ENOMEM;
 280         s->s_root = d_alloc_root(root);
 281         if (s->s_root == NULL)
 282                 goto outi;
 283
 284         brelse(bh);
 285
 286         return 0;
 287
 288       outi:
 289         iput(root);
 290       out:
 291         brelse(bh);
 292       outnobh:
 293         kfree(qs);
 294         s->s_fs_info = NULL;
 295         return ret;
 296 }
 297
 298 static void qnx4_put_super(struct super_block *sb)
 299 {
 300         struct qnx4_sb_info *qs = qnx4_sb(sb);
 301         kfree( qs->BitMap );
 302         kfree( qs );
 303         sb->s_fs_info = NULL;
 304         return;
 305 }
 306
 307 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
 308 {
 309         return block_write_full_page(page,qnx4_get_block, wbc);
 310 }
 311
 312 static int qnx4_readpage(struct file *file, struct page *page)
 313 {
 314         return block_read_full_page(page,qnx4_get_block);
 315 }
 316
 317 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
 318                         loff_t pos, unsigned len, unsigned flags,
 319                         struct page **pagep, void **fsdata)
 320 {
 321         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
 322         *pagep = NULL;
 323         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 324                                 qnx4_get_block,
 325                                 &qnx4_inode->mmu_private);
 326 }
 327 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 328 {
 329         return generic_block_bmap(mapping,block,qnx4_get_block);
 330 }
 331 static const struct address_space_operations qnx4_aops = {
 332         .readpage       = qnx4_readpage,
 333         .writepage      = qnx4_writepage,
 334         .sync_page      = block_sync_page,
 335         .write_begin    = qnx4_write_begin,
 336         .write_end      = generic_write_end,
 337         .bmap           = qnx4_bmap
 338 };
 339
 340 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 341 {
 342         struct buffer_head *bh;
 343         struct qnx4_inode_entry *raw_inode;
 344         int block;
 345         struct qnx4_inode_entry *qnx4_inode;
 346         struct inode *inode;
 347
 348         inode = iget_locked(sb, ino);
 349         if (!inode)
 350                 return ERR_PTR(-ENOMEM);
 351         if (!(inode->i_state & I_NEW))
 352                 return inode;
 353
 354         qnx4_inode = qnx4_raw_inode(inode);
 355         inode->i_mode = 0;
 356
 357         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 358         if (!ino) {
 359                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 360                                 "out of range\n",
 361                        sb->s_id, ino);
 362                 iget_failed(inode);
 363                 return ERR_PTR(-EIO);
 364         }
 365         block = ino / QNX4_INODES_PER_BLOCK;
 366
 367         if (!(bh = sb_bread(sb, block))) {
 368                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 369                        "%s\n", sb->s_id);
 370                 iget_failed(inode);
 371                 return ERR_PTR(-EIO);
 372         }
 373         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 374             (ino % QNX4_INODES_PER_BLOCK);
 375
 376         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 377         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 378         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 379         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
 380         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 381         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 382         inode->i_mtime.tv_nsec = 0;
 383         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 384         inode->i_atime.tv_nsec = 0;
 385         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 386         inode->i_ctime.tv_nsec = 0;
 387         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 388
 389         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 390         if (S_ISREG(inode->i_mode)) {
 391                 inode->i_fop = &generic_ro_fops;
 392                 inode->i_mapping->a_ops = &qnx4_aops;
 393                 qnx4_i(inode)->mmu_private = inode->i_size;
 394         } else if (S_ISDIR(inode->i_mode)) {
 395                 inode->i_op = &qnx4_dir_inode_operations;
 396                 inode->i_fop = &qnx4_dir_operations;
 397         } else if (S_ISLNK(inode->i_mode)) {
 398                 inode->i_op = &page_symlink_inode_operations;
 399                 inode->i_mapping->a_ops = &qnx4_aops;
 400                 qnx4_i(inode)->mmu_private = inode->i_size;
 401         } else {
 402                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 403                         ino, sb->s_id);
 404                 iget_failed(inode);
 405                 brelse(bh);
 406                 return ERR_PTR(-EIO);
 407         }
 408         brelse(bh);
 409         unlock_new_inode(inode);
 410         return inode;
 411 }
 412
 413 static struct kmem_cache *qnx4_inode_cachep;
 414
 415 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 416 {
 417         struct qnx4_inode_info *ei;
 418         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 419         if (!ei)
 420                 return NULL;
 421         return &ei->vfs_inode;
 422 }
 423
 424 static void qnx4_destroy_inode(struct inode *inode)
 425 {
 426         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 427 }
 428
 429 static void init_once(void *foo)
 430 {
 431         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 432
 433         inode_init_once(&ei->vfs_inode);
 434 }
 435
 436 static int init_inodecache(void)
 437 {
 438         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 439                                              sizeof(struct qnx4_inode_info),
 440                                              0, (SLAB_RECLAIM_ACCOUNT|
 441                                                 SLAB_MEM_SPREAD),
 442                                              init_once);
 443         if (qnx4_inode_cachep == NULL)
 444                 return -ENOMEM;
 445         return 0;
 446 }
 447
 448 static void destroy_inodecache(void)
 449 {
 450         kmem_cache_destroy(qnx4_inode_cachep);
 451 }
 452
 453 static int qnx4_get_sb(struct file_system_type *fs_type,
 454         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 455 {
 456         return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
 457                            mnt);
 458 }
 459
 460 static struct file_system_type qnx4_fs_type = {
 461         .owner          = THIS_MODULE,
 462         .name           = "qnx4",
 463         .get_sb         = qnx4_get_sb,
 464         .kill_sb        = kill_block_super,
 465         .fs_flags       = FS_REQUIRES_DEV,
 466 };
 467
 468 static int __init init_qnx4_fs(void)
 469 {
 470         int err;
 471
 472         err = init_inodecache();
 473         if (err)
 474                 return err;
 475
 476         err = register_filesystem(&qnx4_fs_type);
 477         if (err) {
 478                 destroy_inodecache();
 479                 return err;
 480         }
 481
 482         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 483         return 0;
 484 }
 485
 486 static void __exit exit_qnx4_fs(void)
 487 {
 488         unregister_filesystem(&qnx4_fs_type);
 489         destroy_inodecache();
 490 }
 491
 492 module_init(init_qnx4_fs)
 493 module_exit(exit_qnx4_fs)
 494 MODULE_LICENSE("GPL");
 495