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         if (!create) {
  68                 return NULL;
  69         }
  70 #if 0
  71         tmp = qnx4_new_block(inode->i_sb);
  72         if (!tmp) {
  73                 return NULL;
  74         }
  75         result = sb_getblk(inode->i_sb, tmp);
  76         if (tst) {
  77                 qnx4_free_block(inode->i_sb, tmp);
  78                 brelse(result);
  79                 goto repeat;
  80         }
  81         tst = tmp;
  82 #endif
  83         inode->i_ctime = CURRENT_TIME_SEC;
  84         mark_inode_dirty(inode);
  85         return result;
  86 }
  87
  88 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
  89 {
  90         struct buffer_head *bh;
  91
  92         bh = qnx4_getblk(inode, block, create);
  93         if (!bh || buffer_uptodate(bh)) {
  94                 return bh;
  95         }
  96         ll_rw_block(READ, 1, &bh);
  97         wait_on_buffer(bh);
  98         if (buffer_uptodate(bh)) {
  99                 return bh;
 100         }
 101         brelse(bh);
 102
 103         return NULL;
 104 }
 105
 106 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
 107 {
 108         unsigned long phys;
 109
 110         QNX4DEBUG(("qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
 111
 112         phys = qnx4_block_map( inode, iblock );
 113         if ( phys ) {
 114                 // logical block is before EOF
 115                 map_bh(bh, inode->i_sb, phys);
 116         } else if ( create ) {
 117                 // to be done.
 118         }
 119         return 0;
 120 }
 121
 122 unsigned long qnx4_block_map( struct inode *inode, long iblock )
 123 {
 124         int ix;
 125         long offset, i_xblk;
 126         unsigned long block = 0;
 127         struct buffer_head *bh = NULL;
 128         struct qnx4_xblk *xblk = NULL;
 129         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
 130         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
 131
 132         if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
 133                 // iblock is in the first extent. This is easy.
 134                 block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
 135         } else {
 136                 // iblock is beyond first extent. We have to follow the extent chain.
 137                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
 138                 offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
 139                 ix = 0;
 140                 while ( --nxtnt > 0 ) {
 141                         if ( ix == 0 ) {
 142                                 // read next xtnt block.
 143                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 144                                 if ( !bh ) {
 145                                         QNX4DEBUG(("qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 146                                         return -EIO;
 147                                 }
 148                                 xblk = (struct qnx4_xblk*)bh->b_data;
 149                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 150                                         QNX4DEBUG(("qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 151                                         return -EIO;
 152                                 }
 153                         }
 154                         if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
 155                                 // got it!
 156                                 block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
 157                                 break;
 158                         }
 159                         offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
 160                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 161                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 162                                 ix = 0;
 163                                 brelse( bh );
 164                                 bh = NULL;
 165                         }
 166                 }
 167                 if ( bh )
 168                         brelse( bh );
 169         }
 170
 171         QNX4DEBUG(("qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 172         return block;
 173 }
 174
 175 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 176 {
 177         struct super_block *sb = dentry->d_sb;
 178         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 179
 180         lock_kernel();
 181
 182         buf->f_type    = sb->s_magic;
 183         buf->f_bsize   = sb->s_blocksize;
 184         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 185         buf->f_bfree   = qnx4_count_free_blocks(sb);
 186         buf->f_bavail  = buf->f_bfree;
 187         buf->f_namelen = QNX4_NAME_MAX;
 188         buf->f_fsid.val[0] = (u32)id;
 189         buf->f_fsid.val[1] = (u32)(id >> 32);
 190
 191         unlock_kernel();
 192
 193         return 0;
 194 }
 195
 196 /*
 197  * Check the root directory of the filesystem to make sure
 198  * it really _is_ a qnx4 filesystem, and to check the size
 199  * of the directory entry.
 200  */
 201 static const char *qnx4_checkroot(struct super_block *sb)
 202 {
 203         struct buffer_head *bh;
 204         struct qnx4_inode_entry *rootdir;
 205         int rd, rl;
 206         int i, j;
 207         int found = 0;
 208
 209         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
 210                 return "no qnx4 filesystem (no root dir).";
 211         } else {
 212                 QNX4DEBUG(("QNX4 filesystem found on dev %s.\n", sb->s_id));
 213                 rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 214                 rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 215                 for (j = 0; j < rl; j++) {
 216                         bh = sb_bread(sb, rd + j);      /* root dir, first block */
 217                         if (bh == NULL) {
 218                                 return "unable to read root entry.";
 219                         }
 220                         for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
 221                                 rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
 222                                 if (rootdir->di_fname != NULL) {
 223                                         QNX4DEBUG(("Rootdir entry found : [%s]\n", rootdir->di_fname));
 224                                         if (!strncmp(rootdir->di_fname, QNX4_BMNAME, sizeof QNX4_BMNAME)) {
 225                                                 found = 1;
 226                                                 qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
 227                                                 if (!qnx4_sb(sb)->BitMap) {
 228                                                         brelse (bh);
 229                                                         return "not enough memory for bitmap inode";
 230                                                 }
 231                                                 memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */
 232                                                 break;
 233                                         }
 234                                 }
 235                         }
 236                         brelse(bh);
 237                         if (found != 0) {
 238                                 break;
 239                         }
 240                 }
 241                 if (found == 0) {
 242                         return "bitmap file not found.";
 243                 }
 244         }
 245         return NULL;
 246 }
 247
 248 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 249 {
 250         struct buffer_head *bh;
 251         struct inode *root;
 252         const char *errmsg;
 253         struct qnx4_sb_info *qs;
 254         int ret = -EINVAL;
 255
 256         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 257         if (!qs)
 258                 return -ENOMEM;
 259         s->s_fs_info = qs;
 260
 261         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 262
 263         /* Check the superblock signature. Since the qnx4 code is
 264            dangerous, we should leave as quickly as possible
 265            if we don't belong here... */
 266         bh = sb_bread(s, 1);
 267         if (!bh) {
 268                 printk("qnx4: unable to read the superblock\n");
 269                 goto outnobh;
 270         }
 271         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 272                 if (!silent)
 273                         printk("qnx4: wrong fsid in superblock.\n");
 274                 goto out;
 275         }
 276         s->s_op = &qnx4_sops;
 277         s->s_magic = QNX4_SUPER_MAGIC;
 278         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 279         qnx4_sb(s)->sb_buf = bh;
 280         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 281
 282
 283         /* check before allocating dentries, inodes, .. */
 284         errmsg = qnx4_checkroot(s);
 285         if (errmsg != NULL) {
 286                 if (!silent)
 287                         printk("qnx4: %s\n", errmsg);
 288                 goto out;
 289         }
 290
 291         /* does root not have inode number QNX4_ROOT_INO ?? */
 292         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 293         if (IS_ERR(root)) {
 294                 printk("qnx4: get inode failed\n");
 295                 ret = PTR_ERR(root);
 296                 goto out;
 297         }
 298
 299         ret = -ENOMEM;
 300         s->s_root = d_alloc_root(root);
 301         if (s->s_root == NULL)
 302                 goto outi;
 303
 304         brelse(bh);
 305
 306         return 0;
 307
 308       outi:
 309         iput(root);
 310       out:
 311         brelse(bh);
 312       outnobh:
 313         kfree(qs);
 314         s->s_fs_info = NULL;
 315         return ret;
 316 }
 317
 318 static void qnx4_put_super(struct super_block *sb)
 319 {
 320         struct qnx4_sb_info *qs = qnx4_sb(sb);
 321         kfree( qs->BitMap );
 322         kfree( qs );
 323         sb->s_fs_info = NULL;
 324         return;
 325 }
 326
 327 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
 328 {
 329         return block_write_full_page(page,qnx4_get_block, wbc);
 330 }
 331
 332 static int qnx4_readpage(struct file *file, struct page *page)
 333 {
 334         return block_read_full_page(page,qnx4_get_block);
 335 }
 336
 337 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
 338                         loff_t pos, unsigned len, unsigned flags,
 339                         struct page **pagep, void **fsdata)
 340 {
 341         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
 342         *pagep = NULL;
 343         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 344                                 qnx4_get_block,
 345                                 &qnx4_inode->mmu_private);
 346 }
 347 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 348 {
 349         return generic_block_bmap(mapping,block,qnx4_get_block);
 350 }
 351 static const struct address_space_operations qnx4_aops = {
 352         .readpage       = qnx4_readpage,
 353         .writepage      = qnx4_writepage,
 354         .sync_page      = block_sync_page,
 355         .write_begin    = qnx4_write_begin,
 356         .write_end      = generic_write_end,
 357         .bmap           = qnx4_bmap
 358 };
 359
 360 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 361 {
 362         struct buffer_head *bh;
 363         struct qnx4_inode_entry *raw_inode;
 364         int block;
 365         struct qnx4_inode_entry *qnx4_inode;
 366         struct inode *inode;
 367
 368         inode = iget_locked(sb, ino);
 369         if (!inode)
 370                 return ERR_PTR(-ENOMEM);
 371         if (!(inode->i_state & I_NEW))
 372                 return inode;
 373
 374         qnx4_inode = qnx4_raw_inode(inode);
 375         inode->i_mode = 0;
 376
 377         QNX4DEBUG(("Reading inode : [%d]\n", ino));
 378         if (!ino) {
 379                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 380                                 "out of range\n",
 381                        sb->s_id, ino);
 382                 iget_failed(inode);
 383                 return ERR_PTR(-EIO);
 384         }
 385         block = ino / QNX4_INODES_PER_BLOCK;
 386
 387         if (!(bh = sb_bread(sb, block))) {
 388                 printk("qnx4: major problem: unable to read inode from dev "
 389                        "%s\n", sb->s_id);
 390                 iget_failed(inode);
 391                 return ERR_PTR(-EIO);
 392         }
 393         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 394             (ino % QNX4_INODES_PER_BLOCK);
 395
 396         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 397         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 398         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 399         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
 400         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 401         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 402         inode->i_mtime.tv_nsec = 0;
 403         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 404         inode->i_atime.tv_nsec = 0;
 405         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 406         inode->i_ctime.tv_nsec = 0;
 407         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 408
 409         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 410         if (S_ISREG(inode->i_mode)) {
 411                 inode->i_fop = &generic_ro_fops;
 412                 inode->i_mapping->a_ops = &qnx4_aops;
 413                 qnx4_i(inode)->mmu_private = inode->i_size;
 414         } else if (S_ISDIR(inode->i_mode)) {
 415                 inode->i_op = &qnx4_dir_inode_operations;
 416                 inode->i_fop = &qnx4_dir_operations;
 417         } else if (S_ISLNK(inode->i_mode)) {
 418                 inode->i_op = &page_symlink_inode_operations;
 419                 inode->i_mapping->a_ops = &qnx4_aops;
 420                 qnx4_i(inode)->mmu_private = inode->i_size;
 421         } else {
 422                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 423                         ino, sb->s_id);
 424                 iget_failed(inode);
 425                 brelse(bh);
 426                 return ERR_PTR(-EIO);
 427         }
 428         brelse(bh);
 429         unlock_new_inode(inode);
 430         return inode;
 431 }
 432
 433 static struct kmem_cache *qnx4_inode_cachep;
 434
 435 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 436 {
 437         struct qnx4_inode_info *ei;
 438         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 439         if (!ei)
 440                 return NULL;
 441         return &ei->vfs_inode;
 442 }
 443
 444 static void qnx4_destroy_inode(struct inode *inode)
 445 {
 446         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 447 }
 448
 449 static void init_once(void *foo)
 450 {
 451         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 452
 453         inode_init_once(&ei->vfs_inode);
 454 }
 455
 456 static int init_inodecache(void)
 457 {
 458         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 459                                              sizeof(struct qnx4_inode_info),
 460                                              0, (SLAB_RECLAIM_ACCOUNT|
 461                                                 SLAB_MEM_SPREAD),
 462                                              init_once);
 463         if (qnx4_inode_cachep == NULL)
 464                 return -ENOMEM;
 465         return 0;
 466 }
 467
 468 static void destroy_inodecache(void)
 469 {
 470         kmem_cache_destroy(qnx4_inode_cachep);
 471 }
 472
 473 static int qnx4_get_sb(struct file_system_type *fs_type,
 474         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 475 {
 476         return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
 477                            mnt);
 478 }
 479
 480 static struct file_system_type qnx4_fs_type = {
 481         .owner          = THIS_MODULE,
 482         .name           = "qnx4",
 483         .get_sb         = qnx4_get_sb,
 484         .kill_sb        = kill_block_super,
 485         .fs_flags       = FS_REQUIRES_DEV,
 486 };
 487
 488 static int __init init_qnx4_fs(void)
 489 {
 490         int err;
 491
 492         err = init_inodecache();
 493         if (err)
 494                 return err;
 495
 496         err = register_filesystem(&qnx4_fs_type);
 497         if (err) {
 498                 destroy_inodecache();
 499                 return err;
 500         }
 501
 502         printk("QNX4 filesystem 0.2.3 registered.\n");
 503         return 0;
 504 }
 505
 506 static void __exit exit_qnx4_fs(void)
 507 {
 508         unregister_filesystem(&qnx4_fs_type);
 509         destroy_inodecache();
 510 }
 511
 512 module_init(init_qnx4_fs)
 513 module_exit(exit_qnx4_fs)
 514 MODULE_LICENSE("GPL");
 515