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/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
  28 static const struct super_operations qnx4_sops;
  29
  30 static void qnx4_put_super(struct super_block *sb);
  31 static struct inode *qnx4_alloc_inode(struct super_block *sb);
  32 static void qnx4_destroy_inode(struct inode *inode);
  33 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
  34 static int qnx4_statfs(struct dentry *, struct kstatfs *);
  35
  36 static 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
  45 static 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
  55 static struct buffer_head *qnx4_getblk(struct inode *inode, int nr,
  56                                        int create)
  57 {
  58         struct buffer_head *result = NULL;
  59
  60         if ( nr >= 0 )
  61                 nr = qnx4_block_map( inode, nr );
  62         if (nr) {
  63                 result = sb_getblk(inode->i_sb, nr);
  64                 return result;
  65         }
  66         return NULL;
  67 }
  68
  69 struct buffer_head *qnx4_bread(struct inode *inode, int block, int create)
  70 {
  71         struct buffer_head *bh;
  72
  73         bh = qnx4_getblk(inode, block, create);
  74         if (!bh || buffer_uptodate(bh)) {
  75                 return bh;
  76         }
  77         ll_rw_block(READ, 1, &bh);
  78         wait_on_buffer(bh);
  79         if (buffer_uptodate(bh)) {
  80                 return bh;
  81         }
  82         brelse(bh);
  83
  84         return NULL;
  85 }
  86
  87 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  88 {
  89         unsigned long phys;
  90
  91         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  92
  93         phys = qnx4_block_map( inode, iblock );
  94         if ( phys ) {
  95                 // logical block is before EOF
  96                 map_bh(bh, inode->i_sb, phys);
  97         }
  98         return 0;
  99 }
 100
 101 unsigned long qnx4_block_map( struct inode *inode, long iblock )
 102 {
 103         int ix;
 104         long offset, i_xblk;
 105         unsigned long block = 0;
 106         struct buffer_head *bh = NULL;
 107         struct qnx4_xblk *xblk = NULL;
 108         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
 109         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
 110
 111         if ( iblock < le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size) ) {
 112                 // iblock is in the first extent. This is easy.
 113                 block = le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_blk) + iblock - 1;
 114         } else {
 115                 // iblock is beyond first extent. We have to follow the extent chain.
 116                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
 117                 offset = iblock - le32_to_cpu(qnx4_inode->di_first_xtnt.xtnt_size);
 118                 ix = 0;
 119                 while ( --nxtnt > 0 ) {
 120                         if ( ix == 0 ) {
 121                                 // read next xtnt block.
 122                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 123                                 if ( !bh ) {
 124                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 125                                         return -EIO;
 126                                 }
 127                                 xblk = (struct qnx4_xblk*)bh->b_data;
 128                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 129                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 130                                         return -EIO;
 131                                 }
 132                         }
 133                         if ( offset < le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size) ) {
 134                                 // got it!
 135                                 block = le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_blk) + offset - 1;
 136                                 break;
 137                         }
 138                         offset -= le32_to_cpu(xblk->xblk_xtnts[ix].xtnt_size);
 139                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 140                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 141                                 ix = 0;
 142                                 brelse( bh );
 143                                 bh = NULL;
 144                         }
 145                 }
 146                 if ( bh )
 147                         brelse( bh );
 148         }
 149
 150         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 151         return block;
 152 }
 153
 154 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 155 {
 156         struct super_block *sb = dentry->d_sb;
 157         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 158
 159         buf->f_type    = sb->s_magic;
 160         buf->f_bsize   = sb->s_blocksize;
 161         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 162         buf->f_bfree   = qnx4_count_free_blocks(sb);
 163         buf->f_bavail  = buf->f_bfree;
 164         buf->f_namelen = QNX4_NAME_MAX;
 165         buf->f_fsid.val[0] = (u32)id;
 166         buf->f_fsid.val[1] = (u32)(id >> 32);
 167
 168         return 0;
 169 }
 170
 171 /*
 172  * Check the root directory of the filesystem to make sure
 173  * it really _is_ a qnx4 filesystem, and to check the size
 174  * of the directory entry.
 175  */
 176 static const char *qnx4_checkroot(struct super_block *sb)
 177 {
 178         struct buffer_head *bh;
 179         struct qnx4_inode_entry *rootdir;
 180         int rd, rl;
 181         int i, j;
 182         int found = 0;
 183
 184         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/') {
 185                 return "no qnx4 filesystem (no root dir).";
 186         } else {
 187                 QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 188                 rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 189                 rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 190                 for (j = 0; j < rl; j++) {
 191                         bh = sb_bread(sb, rd + j);      /* root dir, first block */
 192                         if (bh == NULL) {
 193                                 return "unable to read root entry.";
 194                         }
 195                         for (i = 0; i < QNX4_INODES_PER_BLOCK; i++) {
 196                                 rootdir = (struct qnx4_inode_entry *) (bh->b_data + i * QNX4_DIR_ENTRY_SIZE);
 197                                 if (rootdir->di_fname != NULL) {
 198                                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 199                                         if (!strcmp(rootdir->di_fname,
 200                                                     QNX4_BMNAME)) {
 201                                                 found = 1;
 202                                                 qnx4_sb(sb)->BitMap = kmalloc( sizeof( struct qnx4_inode_entry ), GFP_KERNEL );
 203                                                 if (!qnx4_sb(sb)->BitMap) {
 204                                                         brelse (bh);
 205                                                         return "not enough memory for bitmap inode";
 206                                                 }
 207                                                 memcpy( qnx4_sb(sb)->BitMap, rootdir, sizeof( struct qnx4_inode_entry ) );      /* keep bitmap inode known */
 208                                                 break;
 209                                         }
 210                                 }
 211                         }
 212                         brelse(bh);
 213                         if (found != 0) {
 214                                 break;
 215                         }
 216                 }
 217                 if (found == 0) {
 218                         return "bitmap file not found.";
 219                 }
 220         }
 221         return NULL;
 222 }
 223
 224 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 225 {
 226         struct buffer_head *bh;
 227         struct inode *root;
 228         const char *errmsg;
 229         struct qnx4_sb_info *qs;
 230         int ret = -EINVAL;
 231
 232         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 233         if (!qs)
 234                 return -ENOMEM;
 235         s->s_fs_info = qs;
 236
 237         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 238
 239         /* Check the superblock signature. Since the qnx4 code is
 240            dangerous, we should leave as quickly as possible
 241            if we don't belong here... */
 242         bh = sb_bread(s, 1);
 243         if (!bh) {
 244                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 245                 goto outnobh;
 246         }
 247         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 248                 if (!silent)
 249                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 250                 goto out;
 251         }
 252         s->s_op = &qnx4_sops;
 253         s->s_magic = QNX4_SUPER_MAGIC;
 254         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 255         qnx4_sb(s)->sb_buf = bh;
 256         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 257
 258
 259         /* check before allocating dentries, inodes, .. */
 260         errmsg = qnx4_checkroot(s);
 261         if (errmsg != NULL) {
 262                 if (!silent)
 263                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 264                 goto out;
 265         }
 266
 267         /* does root not have inode number QNX4_ROOT_INO ?? */
 268         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 269         if (IS_ERR(root)) {
 270                 printk(KERN_ERR "qnx4: get inode failed\n");
 271                 ret = PTR_ERR(root);
 272                 goto out;
 273         }
 274
 275         ret = -ENOMEM;
 276         s->s_root = d_alloc_root(root);
 277         if (s->s_root == NULL)
 278                 goto outi;
 279
 280         brelse(bh);
 281         return 0;
 282
 283       outi:
 284         iput(root);
 285       out:
 286         brelse(bh);
 287       outnobh:
 288         kfree(qs);
 289         s->s_fs_info = NULL;
 290         return ret;
 291 }
 292
 293 static void qnx4_put_super(struct super_block *sb)
 294 {
 295         struct qnx4_sb_info *qs = qnx4_sb(sb);
 296         kfree( qs->BitMap );
 297         kfree( qs );
 298         sb->s_fs_info = NULL;
 299         return;
 300 }
 301
 302 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
 303 {
 304         return block_write_full_page(page,qnx4_get_block, wbc);
 305 }
 306
 307 static int qnx4_readpage(struct file *file, struct page *page)
 308 {
 309         return block_read_full_page(page,qnx4_get_block);
 310 }
 311
 312 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
 313                         loff_t pos, unsigned len, unsigned flags,
 314                         struct page **pagep, void **fsdata)
 315 {
 316         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
 317         int ret;
 318
 319         *pagep = NULL;
 320         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 321                                 qnx4_get_block,
 322                                 &qnx4_inode->mmu_private);
 323         if (unlikely(ret)) {
 324                 loff_t isize = mapping->host->i_size;
 325                 if (pos + len > isize)
 326                         vmtruncate(mapping->host, isize);
 327         }
 328
 329         return ret;
 330 }
 331 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 332 {
 333         return generic_block_bmap(mapping,block,qnx4_get_block);
 334 }
 335 static const struct address_space_operations qnx4_aops = {
 336         .readpage       = qnx4_readpage,
 337         .writepage      = qnx4_writepage,
 338         .write_begin    = qnx4_write_begin,
 339         .write_end      = generic_write_end,
 340         .bmap           = qnx4_bmap
 341 };
 342
 343 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 344 {
 345         struct buffer_head *bh;
 346         struct qnx4_inode_entry *raw_inode;
 347         int block;
 348         struct qnx4_inode_entry *qnx4_inode;
 349         struct inode *inode;
 350
 351         inode = iget_locked(sb, ino);
 352         if (!inode)
 353                 return ERR_PTR(-ENOMEM);
 354         if (!(inode->i_state & I_NEW))
 355                 return inode;
 356
 357         qnx4_inode = qnx4_raw_inode(inode);
 358         inode->i_mode = 0;
 359
 360         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 361         if (!ino) {
 362                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 363                                 "out of range\n",
 364                        sb->s_id, ino);
 365                 iget_failed(inode);
 366                 return ERR_PTR(-EIO);
 367         }
 368         block = ino / QNX4_INODES_PER_BLOCK;
 369
 370         if (!(bh = sb_bread(sb, block))) {
 371                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 372                        "%s\n", sb->s_id);
 373                 iget_failed(inode);
 374                 return ERR_PTR(-EIO);
 375         }
 376         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 377             (ino % QNX4_INODES_PER_BLOCK);
 378
 379         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 380         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 381         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 382         inode->i_nlink   = le16_to_cpu(raw_inode->di_nlink);
 383         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 384         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 385         inode->i_mtime.tv_nsec = 0;
 386         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 387         inode->i_atime.tv_nsec = 0;
 388         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 389         inode->i_ctime.tv_nsec = 0;
 390         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 391
 392         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 393         if (S_ISREG(inode->i_mode)) {
 394                 inode->i_fop = &generic_ro_fops;
 395                 inode->i_mapping->a_ops = &qnx4_aops;
 396                 qnx4_i(inode)->mmu_private = inode->i_size;
 397         } else if (S_ISDIR(inode->i_mode)) {
 398                 inode->i_op = &qnx4_dir_inode_operations;
 399                 inode->i_fop = &qnx4_dir_operations;
 400         } else if (S_ISLNK(inode->i_mode)) {
 401                 inode->i_op = &page_symlink_inode_operations;
 402                 inode->i_mapping->a_ops = &qnx4_aops;
 403                 qnx4_i(inode)->mmu_private = inode->i_size;
 404         } else {
 405                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 406                         ino, sb->s_id);
 407                 iget_failed(inode);
 408                 brelse(bh);
 409                 return ERR_PTR(-EIO);
 410         }
 411         brelse(bh);
 412         unlock_new_inode(inode);
 413         return inode;
 414 }
 415
 416 static struct kmem_cache *qnx4_inode_cachep;
 417
 418 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 419 {
 420         struct qnx4_inode_info *ei;
 421         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 422         if (!ei)
 423                 return NULL;
 424         return &ei->vfs_inode;
 425 }
 426
 427 static void qnx4_i_callback(struct rcu_head *head)
 428 {
 429         struct inode *inode = container_of(head, struct inode, i_rcu);
 430         INIT_LIST_HEAD(&inode->i_dentry);
 431         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 432 }
 433
 434 static void qnx4_destroy_inode(struct inode *inode)
 435 {
 436         call_rcu(&inode->i_rcu, qnx4_i_callback);
 437 }
 438
 439 static void init_once(void *foo)
 440 {
 441         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 442
 443         inode_init_once(&ei->vfs_inode);
 444 }
 445
 446 static int init_inodecache(void)
 447 {
 448         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 449                                              sizeof(struct qnx4_inode_info),
 450                                              0, (SLAB_RECLAIM_ACCOUNT|
 451                                                 SLAB_MEM_SPREAD),
 452                                              init_once);
 453         if (qnx4_inode_cachep == NULL)
 454                 return -ENOMEM;
 455         return 0;
 456 }
 457
 458 static void destroy_inodecache(void)
 459 {
 460         kmem_cache_destroy(qnx4_inode_cachep);
 461 }
 462
 463 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 464         int flags, const char *dev_name, void *data)
 465 {
 466         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 467 }
 468
 469 static struct file_system_type qnx4_fs_type = {
 470         .owner          = THIS_MODULE,
 471         .name           = "qnx4",
 472         .mount          = qnx4_mount,
 473         .kill_sb        = kill_block_super,
 474         .fs_flags       = FS_REQUIRES_DEV,
 475 };
 476
 477 static int __init init_qnx4_fs(void)
 478 {
 479         int err;
 480
 481         err = init_inodecache();
 482         if (err)
 483                 return err;
 484
 485         err = register_filesystem(&qnx4_fs_type);
 486         if (err) {
 487                 destroy_inodecache();
 488                 return err;
 489         }
 490
 491         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 492         return 0;
 493 }
 494
 495 static void __exit exit_qnx4_fs(void)
 496 {
 497         unregister_filesystem(&qnx4_fs_type);
 498         destroy_inodecache();
 499 }
 500
 501 module_init(init_qnx4_fs)
 502 module_exit(exit_qnx4_fs)
 503 MODULE_LICENSE("GPL");
 504