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 (!strcmp(rootdir->di_fname,
 205                                                     QNX4_BMNAME)) {
 206                                                 found = 1;
 207                                                 qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
 208                                                 if (!qnx4_sb(sb)->BitMap) {
 209                                                         brelse (bh);
 210                                                         return "not enough memory for bitmap inode";
 211                                                 }
 212                                                 memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */
 213                                                 break;
 214                                         }
 215                                 }
 216                         }
 217                         brelse(bh);
 218                         if (found != 0) {
 219                                 break;
 220                         }
 221                 }
 222                 if (found == 0) {
 223                         return "bitmap file not found.";
 224                 }
 225         }
 226         return NULL;
 227 }
 228
 229 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 230 {
 231         struct buffer_head *bh;
 232         struct inode *root;
 233         const char *errmsg;
 234         struct qnx4_sb_info *qs;
 235         int ret = -EINVAL;
 236
 237         lock_kernel();
 238
 239         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 240         if (!qs) {
 241                 unlock_kernel();
 242                 return -ENOMEM;
 243         }
 244         s->s_fs_info = qs;
 245
 246         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 247
 248         /* Check the superblock signature. Since the qnx4 code is
 249            dangerous, we should leave as quickly as possible
 250            if we don't belong here... */
 251         bh = sb_bread(s, 1);
 252         if (!bh) {
 253                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 254                 goto outnobh;
 255         }
 256         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 257                 if (!silent)
 258                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 259                 goto out;
 260         }
 261         s->s_op = &qnx4_sops;
 262         s->s_magic = QNX4_SUPER_MAGIC;
 263         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 264         qnx4_sb(s)->sb_buf = bh;
 265         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 266
 267
 268         /* check before allocating dentries, inodes, .. */
 269         errmsg = qnx4_checkroot(s);
 270         if (errmsg != NULL) {
 271                 if (!silent)
 272                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 273                 goto out;
 274         }
 275
 276         /* does root not have inode number QNX4_ROOT_INO ?? */
 277         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 278         if (IS_ERR(root)) {
 279                 printk(KERN_ERR "qnx4: get inode failed\n");
 280                 ret = PTR_ERR(root);
 281                 goto out;
 282         }
 283
 284         ret = -ENOMEM;
 285         s->s_root = d_alloc_root(root);
 286         if (s->s_root == NULL)
 287                 goto outi;
 288
 289         brelse(bh);
 290
 291         unlock_kernel();
 292         return 0;
 293
 294       outi:
 295         iput(root);
 296       out:
 297         brelse(bh);
 298       outnobh:
 299         kfree(qs);
 300         s->s_fs_info = NULL;
 301         unlock_kernel();
 302         return ret;
 303 }
 304
 305 static void qnx4_put_super(struct super_block *sb)
 306 {
 307         struct qnx4_sb_info *qs = qnx4_sb(sb);
 308         kfree( qs->BitMap );
 309         kfree( qs );
 310         sb->s_fs_info = NULL;
 311         return;
 312 }
 313
 314 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
 315 {
 316         return block_write_full_page(page,qnx4_get_block, wbc);
 317 }
 318
 319 static int qnx4_readpage(struct file *file, struct page *page)
 320 {
 321         return block_read_full_page(page,qnx4_get_block);
 322 }
 323
 324 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
 325                         loff_t pos, unsigned len, unsigned flags,
 326                         struct page **pagep, void **fsdata)
 327 {
 328         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
 329         int ret;
 330
 331         *pagep = NULL;
 332         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 333                                 qnx4_get_block,
 334                                 &qnx4_inode->mmu_private);
 335         if (unlikely(ret)) {
 336                 loff_t isize = mapping->host->i_size;
 337                 if (pos + len > isize)
 338                         vmtruncate(mapping->host, isize);
 339         }
 340
 341         return ret;
 342 }
 343 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 344 {
 345         return generic_block_bmap(mapping,block,qnx4_get_block);
 346 }
 347 static const struct address_space_operations qnx4_aops = {
 348         .readpage       = qnx4_readpage,
 349         .writepage      = qnx4_writepage,
 350         .sync_page      = block_sync_page,
 351         .write_begin    = qnx4_write_begin,
 352         .write_end      = generic_write_end,
 353         .bmap           = qnx4_bmap
 354 };
 355
 356 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 357 {
 358         struct buffer_head *bh;
 359         struct qnx4_inode_entry *raw_inode;
 360         int block;
 361         struct qnx4_inode_entry *qnx4_inode;
 362         struct inode *inode;
 363
 364         inode = iget_locked(sb, ino);
 365         if (!inode)
 366                 return ERR_PTR(-ENOMEM);
 367         if (!(inode->i_state & I_NEW))
 368                 return inode;
 369
 370         qnx4_inode = qnx4_raw_inode(inode);
 371         inode->i_mode = 0;
 372
 373         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 374         if (!ino) {
 375                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 376                                 "out of range\n",
 377                        sb->s_id, ino);
 378                 iget_failed(inode);
 379                 return ERR_PTR(-EIO);
 380         }
 381         block = ino / QNX4_INODES_PER_BLOCK;
 382
 383         if (!(bh = sb_bread(sb, block))) {
 384                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 385                        "%s\n", sb->s_id);
 386                 iget_failed(inode);
 387                 return ERR_PTR(-EIO);
 388         }
 389         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 390             (ino % QNX4_INODES_PER_BLOCK);
 391
 392         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 393         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 394         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 395         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
 396         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 397         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 398         inode->i_mtime.tv_nsec = 0;
 399         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 400         inode->i_atime.tv_nsec = 0;
 401         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 402         inode->i_ctime.tv_nsec = 0;
 403         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 404
 405         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 406         if (S_ISREG(inode->i_mode)) {
 407                 inode->i_fop = &generic_ro_fops;
 408                 inode->i_mapping->a_ops = &qnx4_aops;
 409                 qnx4_i(inode)->mmu_private = inode->i_size;
 410         } else if (S_ISDIR(inode->i_mode)) {
 411                 inode->i_op = &qnx4_dir_inode_operations;
 412                 inode->i_fop = &qnx4_dir_operations;
 413         } else if (S_ISLNK(inode->i_mode)) {
 414                 inode->i_op = &page_symlink_inode_operations;
 415                 inode->i_mapping->a_ops = &qnx4_aops;
 416                 qnx4_i(inode)->mmu_private = inode->i_size;
 417         } else {
 418                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 419                         ino, sb->s_id);
 420                 iget_failed(inode);
 421                 brelse(bh);
 422                 return ERR_PTR(-EIO);
 423         }
 424         brelse(bh);
 425         unlock_new_inode(inode);
 426         return inode;
 427 }
 428
 429 static struct kmem_cache *qnx4_inode_cachep;
 430
 431 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 432 {
 433         struct qnx4_inode_info *ei;
 434         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 435         if (!ei)
 436                 return NULL;
 437         return &ei->vfs_inode;
 438 }
 439
 440 static void qnx4_destroy_inode(struct inode *inode)
 441 {
 442         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 443 }
 444
 445 static void init_once(void *foo)
 446 {
 447         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 448
 449         inode_init_once(&ei->vfs_inode);
 450 }
 451
 452 static int init_inodecache(void)
 453 {
 454         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 455                                              sizeof(struct qnx4_inode_info),
 456                                              0, (SLAB_RECLAIM_ACCOUNT|
 457                                                 SLAB_MEM_SPREAD),
 458                                              init_once);
 459         if (qnx4_inode_cachep == NULL)
 460                 return -ENOMEM;
 461         return 0;
 462 }
 463
 464 static void destroy_inodecache(void)
 465 {
 466         kmem_cache_destroy(qnx4_inode_cachep);
 467 }
 468
 469 static int qnx4_get_sb(struct file_system_type *fs_type,
 470         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
 471 {
 472         return get_sb_bdev(fs_type, flags, dev_name, data, qnx4_fill_super,
 473                            mnt);
 474 }
 475
 476 static struct file_system_type qnx4_fs_type = {
 477         .owner          = THIS_MODULE,
 478         .name           = "qnx4",
 479         .get_sb         = qnx4_get_sb,
 480         .kill_sb        = kill_block_super,
 481         .fs_flags       = FS_REQUIRES_DEV,
 482 };
 483
 484 static int __init init_qnx4_fs(void)
 485 {
 486         int err;
 487
 488         err = init_inodecache();
 489         if (err)
 490                 return err;
 491
 492         err = register_filesystem(&qnx4_fs_type);
 493         if (err) {
 494                 destroy_inodecache();
 495                 return err;
 496         }
 497
 498         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 499         return 0;
 500 }
 501
 502 static void __exit exit_qnx4_fs(void)
 503 {
 504         unregister_filesystem(&qnx4_fs_type);
 505         destroy_inodecache();
 506 }
 507
 508 module_init(init_qnx4_fs)
 509 module_exit(exit_qnx4_fs)
 510 MODULE_LICENSE("GPL");
 511