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
 183         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/')
 184                 return "no qnx4 filesystem (no root dir).";
 185         QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 186         rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 187         rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 188         for (j = 0; j < rl; j++) {
 189                 bh = sb_bread(sb, rd + j);      /* root dir, first block */
 190                 if (bh == NULL)
 191                         return "unable to read root entry.";
 192                 rootdir = (struct qnx4_inode_entry *) bh->b_data;
 193                 for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
 194                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 195                         if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
 196                                 continue;
 197                         qnx4_sb(sb)->BitMap = kmemdup(rootdir,
 198                                                       sizeof(struct qnx4_inode_entry),
 199                                                       GFP_KERNEL);
 200                         brelse(bh);
 201                         if (!qnx4_sb(sb)->BitMap)
 202                                 return "not enough memory for bitmap inode";
 203                         /* keep bitmap inode known */
 204                         return NULL;
 205                 }
 206                 brelse(bh);
 207         }
 208         return "bitmap file not found.";
 209 }
 210
 211 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 212 {
 213         struct buffer_head *bh;
 214         struct inode *root;
 215         const char *errmsg;
 216         struct qnx4_sb_info *qs;
 217         int ret = -EINVAL;
 218
 219         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 220         if (!qs)
 221                 return -ENOMEM;
 222         s->s_fs_info = qs;
 223
 224         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 225
 226         /* Check the superblock signature. Since the qnx4 code is
 227            dangerous, we should leave as quickly as possible
 228            if we don't belong here... */
 229         bh = sb_bread(s, 1);
 230         if (!bh) {
 231                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 232                 goto outnobh;
 233         }
 234         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 235                 if (!silent)
 236                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 237                 goto out;
 238         }
 239         s->s_op = &qnx4_sops;
 240         s->s_magic = QNX4_SUPER_MAGIC;
 241         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 242         qnx4_sb(s)->sb_buf = bh;
 243         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 244
 245
 246         /* check before allocating dentries, inodes, .. */
 247         errmsg = qnx4_checkroot(s);
 248         if (errmsg != NULL) {
 249                 if (!silent)
 250                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 251                 goto out;
 252         }
 253
 254         /* does root not have inode number QNX4_ROOT_INO ?? */
 255         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 256         if (IS_ERR(root)) {
 257                 printk(KERN_ERR "qnx4: get inode failed\n");
 258                 ret = PTR_ERR(root);
 259                 goto outb;
 260         }
 261
 262         ret = -ENOMEM;
 263         s->s_root = d_alloc_root(root);
 264         if (s->s_root == NULL)
 265                 goto outi;
 266
 267         brelse(bh);
 268         return 0;
 269
 270       outi:
 271         iput(root);
 272       outb:
 273         kfree(qs->BitMap);
 274       out:
 275         brelse(bh);
 276       outnobh:
 277         kfree(qs);
 278         s->s_fs_info = NULL;
 279         return ret;
 280 }
 281
 282 static void qnx4_put_super(struct super_block *sb)
 283 {
 284         struct qnx4_sb_info *qs = qnx4_sb(sb);
 285         kfree( qs->BitMap );
 286         kfree( qs );
 287         sb->s_fs_info = NULL;
 288         return;
 289 }
 290
 291 static int qnx4_writepage(struct page *page, struct writeback_control *wbc)
 292 {
 293         return block_write_full_page(page,qnx4_get_block, wbc);
 294 }
 295
 296 static int qnx4_readpage(struct file *file, struct page *page)
 297 {
 298         return block_read_full_page(page,qnx4_get_block);
 299 }
 300
 301 static int qnx4_write_begin(struct file *file, struct address_space *mapping,
 302                         loff_t pos, unsigned len, unsigned flags,
 303                         struct page **pagep, void **fsdata)
 304 {
 305         struct qnx4_inode_info *qnx4_inode = qnx4_i(mapping->host);
 306         int ret;
 307
 308         *pagep = NULL;
 309         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 310                                 qnx4_get_block,
 311                                 &qnx4_inode->mmu_private);
 312         if (unlikely(ret)) {
 313                 loff_t isize = mapping->host->i_size;
 314                 if (pos + len > isize)
 315                         vmtruncate(mapping->host, isize);
 316         }
 317
 318         return ret;
 319 }
 320 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 321 {
 322         return generic_block_bmap(mapping,block,qnx4_get_block);
 323 }
 324 static const struct address_space_operations qnx4_aops = {
 325         .readpage       = qnx4_readpage,
 326         .writepage      = qnx4_writepage,
 327         .write_begin    = qnx4_write_begin,
 328         .write_end      = generic_write_end,
 329         .bmap           = qnx4_bmap
 330 };
 331
 332 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 333 {
 334         struct buffer_head *bh;
 335         struct qnx4_inode_entry *raw_inode;
 336         int block;
 337         struct qnx4_inode_entry *qnx4_inode;
 338         struct inode *inode;
 339
 340         inode = iget_locked(sb, ino);
 341         if (!inode)
 342                 return ERR_PTR(-ENOMEM);
 343         if (!(inode->i_state & I_NEW))
 344                 return inode;
 345
 346         qnx4_inode = qnx4_raw_inode(inode);
 347         inode->i_mode = 0;
 348
 349         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 350         if (!ino) {
 351                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 352                                 "out of range\n",
 353                        sb->s_id, ino);
 354                 iget_failed(inode);
 355                 return ERR_PTR(-EIO);
 356         }
 357         block = ino / QNX4_INODES_PER_BLOCK;
 358
 359         if (!(bh = sb_bread(sb, block))) {
 360                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 361                        "%s\n", sb->s_id);
 362                 iget_failed(inode);
 363                 return ERR_PTR(-EIO);
 364         }
 365         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 366             (ino % QNX4_INODES_PER_BLOCK);
 367
 368         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 369         inode->i_uid     = (uid_t)le16_to_cpu(raw_inode->di_uid);
 370         inode->i_gid     = (gid_t)le16_to_cpu(raw_inode->di_gid);
 371         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 372         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 373         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 374         inode->i_mtime.tv_nsec = 0;
 375         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 376         inode->i_atime.tv_nsec = 0;
 377         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 378         inode->i_ctime.tv_nsec = 0;
 379         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 380
 381         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 382         if (S_ISREG(inode->i_mode)) {
 383                 inode->i_fop = &generic_ro_fops;
 384                 inode->i_mapping->a_ops = &qnx4_aops;
 385                 qnx4_i(inode)->mmu_private = inode->i_size;
 386         } else if (S_ISDIR(inode->i_mode)) {
 387                 inode->i_op = &qnx4_dir_inode_operations;
 388                 inode->i_fop = &qnx4_dir_operations;
 389         } else if (S_ISLNK(inode->i_mode)) {
 390                 inode->i_op = &page_symlink_inode_operations;
 391                 inode->i_mapping->a_ops = &qnx4_aops;
 392                 qnx4_i(inode)->mmu_private = inode->i_size;
 393         } else {
 394                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 395                         ino, sb->s_id);
 396                 iget_failed(inode);
 397                 brelse(bh);
 398                 return ERR_PTR(-EIO);
 399         }
 400         brelse(bh);
 401         unlock_new_inode(inode);
 402         return inode;
 403 }
 404
 405 static struct kmem_cache *qnx4_inode_cachep;
 406
 407 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 408 {
 409         struct qnx4_inode_info *ei;
 410         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 411         if (!ei)
 412                 return NULL;
 413         return &ei->vfs_inode;
 414 }
 415
 416 static void qnx4_i_callback(struct rcu_head *head)
 417 {
 418         struct inode *inode = container_of(head, struct inode, i_rcu);
 419         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 420 }
 421
 422 static void qnx4_destroy_inode(struct inode *inode)
 423 {
 424         call_rcu(&inode->i_rcu, qnx4_i_callback);
 425 }
 426
 427 static void init_once(void *foo)
 428 {
 429         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 430
 431         inode_init_once(&ei->vfs_inode);
 432 }
 433
 434 static int init_inodecache(void)
 435 {
 436         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 437                                              sizeof(struct qnx4_inode_info),
 438                                              0, (SLAB_RECLAIM_ACCOUNT|
 439                                                 SLAB_MEM_SPREAD),
 440                                              init_once);
 441         if (qnx4_inode_cachep == NULL)
 442                 return -ENOMEM;
 443         return 0;
 444 }
 445
 446 static void destroy_inodecache(void)
 447 {
 448         kmem_cache_destroy(qnx4_inode_cachep);
 449 }
 450
 451 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 452         int flags, const char *dev_name, void *data)
 453 {
 454         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 455 }
 456
 457 static struct file_system_type qnx4_fs_type = {
 458         .owner          = THIS_MODULE,
 459         .name           = "qnx4",
 460         .mount          = qnx4_mount,
 461         .kill_sb        = kill_block_super,
 462         .fs_flags       = FS_REQUIRES_DEV,
 463 };
 464
 465 static int __init init_qnx4_fs(void)
 466 {
 467         int err;
 468
 469         err = init_inodecache();
 470         if (err)
 471                 return err;
 472
 473         err = register_filesystem(&qnx4_fs_type);
 474         if (err) {
 475                 destroy_inodecache();
 476                 return err;
 477         }
 478
 479         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 480         return 0;
 481 }
 482
 483 static void __exit exit_qnx4_fs(void)
 484 {
 485         unregister_filesystem(&qnx4_fs_type);
 486         destroy_inodecache();
 487 }
 488
 489 module_init(init_qnx4_fs)
 490 module_exit(exit_qnx4_fs)
 491 MODULE_LICENSE("GPL");
 492