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         sync_filesystem(sb);
  50         qs = qnx4_sb(sb);
  51         qs->Version = QNX4_VERSION;
  52         *flags |= MS_RDONLY;
  53         return 0;
  54 }
  55
  56 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  57 {
  58         unsigned long phys;
  59
  60         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  61
  62         phys = qnx4_block_map( inode, iblock );
  63         if ( phys ) {
  64                 // logical block is before EOF
  65                 map_bh(bh, inode->i_sb, phys);
  66         }
  67         return 0;
  68 }
  69
  70 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
  71 {
  72         u32 size = le32_to_cpu(extent->xtnt_size);
  73         if (*offset < size)
  74                 return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
  75         *offset -= size;
  76         return 0;
  77 }
  78
  79 unsigned long qnx4_block_map( struct inode *inode, long iblock )
  80 {
  81         int ix;
  82         long i_xblk;
  83         struct buffer_head *bh = NULL;
  84         struct qnx4_xblk *xblk = NULL;
  85         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
  86         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
  87         u32 offset = iblock;
  88         u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
  89
  90         if (block) {
  91                 // iblock is in the first extent. This is easy.
  92         } else {
  93                 // iblock is beyond first extent. We have to follow the extent chain.
  94                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
  95                 ix = 0;
  96                 while ( --nxtnt > 0 ) {
  97                         if ( ix == 0 ) {
  98                                 // read next xtnt block.
  99                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
 100                                 if ( !bh ) {
 101                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 102                                         return -EIO;
 103                                 }
 104                                 xblk = (struct qnx4_xblk*)bh->b_data;
 105                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 106                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 107                                         return -EIO;
 108                                 }
 109                         }
 110                         block = try_extent(&xblk->xblk_xtnts[ix], &offset);
 111                         if (block) {
 112                                 // got it!
 113                                 break;
 114                         }
 115                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 116                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 117                                 ix = 0;
 118                                 brelse( bh );
 119                                 bh = NULL;
 120                         }
 121                 }
 122                 if ( bh )
 123                         brelse( bh );
 124         }
 125
 126         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 127         return block;
 128 }
 129
 130 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 131 {
 132         struct super_block *sb = dentry->d_sb;
 133         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 134
 135         buf->f_type    = sb->s_magic;
 136         buf->f_bsize   = sb->s_blocksize;
 137         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 138         buf->f_bfree   = qnx4_count_free_blocks(sb);
 139         buf->f_bavail  = buf->f_bfree;
 140         buf->f_namelen = QNX4_NAME_MAX;
 141         buf->f_fsid.val[0] = (u32)id;
 142         buf->f_fsid.val[1] = (u32)(id >> 32);
 143
 144         return 0;
 145 }
 146
 147 /*
 148  * Check the root directory of the filesystem to make sure
 149  * it really _is_ a qnx4 filesystem, and to check the size
 150  * of the directory entry.
 151  */
 152 static const char *qnx4_checkroot(struct super_block *sb)
 153 {
 154         struct buffer_head *bh;
 155         struct qnx4_inode_entry *rootdir;
 156         int rd, rl;
 157         int i, j;
 158
 159         if (*(qnx4_sb(sb)->sb->RootDir.di_fname) != '/')
 160                 return "no qnx4 filesystem (no root dir).";
 161         QNX4DEBUG((KERN_NOTICE "QNX4 filesystem found on dev %s.\n", sb->s_id));
 162         rd = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_blk) - 1;
 163         rl = le32_to_cpu(qnx4_sb(sb)->sb->RootDir.di_first_xtnt.xtnt_size);
 164         for (j = 0; j < rl; j++) {
 165                 bh = sb_bread(sb, rd + j);      /* root dir, first block */
 166                 if (bh == NULL)
 167                         return "unable to read root entry.";
 168                 rootdir = (struct qnx4_inode_entry *) bh->b_data;
 169                 for (i = 0; i < QNX4_INODES_PER_BLOCK; i++, rootdir++) {
 170                         QNX4DEBUG((KERN_INFO "rootdir entry found : [%s]\n", rootdir->di_fname));
 171                         if (strcmp(rootdir->di_fname, QNX4_BMNAME) != 0)
 172                                 continue;
 173                         qnx4_sb(sb)->BitMap = kmemdup(rootdir,
 174                                                       sizeof(struct qnx4_inode_entry),
 175                                                       GFP_KERNEL);
 176                         brelse(bh);
 177                         if (!qnx4_sb(sb)->BitMap)
 178                                 return "not enough memory for bitmap inode";
 179                         /* keep bitmap inode known */
 180                         return NULL;
 181                 }
 182                 brelse(bh);
 183         }
 184         return "bitmap file not found.";
 185 }
 186
 187 static int qnx4_fill_super(struct super_block *s, void *data, int silent)
 188 {
 189         struct buffer_head *bh;
 190         struct inode *root;
 191         const char *errmsg;
 192         struct qnx4_sb_info *qs;
 193         int ret = -EINVAL;
 194
 195         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 196         if (!qs)
 197                 return -ENOMEM;
 198         s->s_fs_info = qs;
 199
 200         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 201
 202         /* Check the superblock signature. Since the qnx4 code is
 203            dangerous, we should leave as quickly as possible
 204            if we don't belong here... */
 205         bh = sb_bread(s, 1);
 206         if (!bh) {
 207                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 208                 goto outnobh;
 209         }
 210         if ( le32_to_cpup((__le32*) bh->b_data) != QNX4_SUPER_MAGIC ) {
 211                 if (!silent)
 212                         printk(KERN_ERR "qnx4: wrong fsid in superblock.\n");
 213                 goto out;
 214         }
 215         s->s_op = &qnx4_sops;
 216         s->s_magic = QNX4_SUPER_MAGIC;
 217         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 218         qnx4_sb(s)->sb_buf = bh;
 219         qnx4_sb(s)->sb = (struct qnx4_super_block *) bh->b_data;
 220
 221
 222         /* check before allocating dentries, inodes, .. */
 223         errmsg = qnx4_checkroot(s);
 224         if (errmsg != NULL) {
 225                 if (!silent)
 226                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 227                 goto out;
 228         }
 229
 230         /* does root not have inode number QNX4_ROOT_INO ?? */
 231         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 232         if (IS_ERR(root)) {
 233                 printk(KERN_ERR "qnx4: get inode failed\n");
 234                 ret = PTR_ERR(root);
 235                 goto outb;
 236         }
 237
 238         ret = -ENOMEM;
 239         s->s_root = d_make_root(root);
 240         if (s->s_root == NULL)
 241                 goto outb;
 242
 243         brelse(bh);
 244         return 0;
 245
 246       outb:
 247         kfree(qs->BitMap);
 248       out:
 249         brelse(bh);
 250       outnobh:
 251         kfree(qs);
 252         s->s_fs_info = NULL;
 253         return ret;
 254 }
 255
 256 static void qnx4_put_super(struct super_block *sb)
 257 {
 258         struct qnx4_sb_info *qs = qnx4_sb(sb);
 259         kfree( qs->BitMap );
 260         kfree( qs );
 261         sb->s_fs_info = NULL;
 262         return;
 263 }
 264
 265 static int qnx4_readpage(struct file *file, struct page *page)
 266 {
 267         return block_read_full_page(page,qnx4_get_block);
 268 }
 269
 270 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 271 {
 272         return generic_block_bmap(mapping,block,qnx4_get_block);
 273 }
 274 static const struct address_space_operations qnx4_aops = {
 275         .readpage       = qnx4_readpage,
 276         .bmap           = qnx4_bmap
 277 };
 278
 279 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 280 {
 281         struct buffer_head *bh;
 282         struct qnx4_inode_entry *raw_inode;
 283         int block;
 284         struct qnx4_inode_entry *qnx4_inode;
 285         struct inode *inode;
 286
 287         inode = iget_locked(sb, ino);
 288         if (!inode)
 289                 return ERR_PTR(-ENOMEM);
 290         if (!(inode->i_state & I_NEW))
 291                 return inode;
 292
 293         qnx4_inode = qnx4_raw_inode(inode);
 294         inode->i_mode = 0;
 295
 296         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 297         if (!ino) {
 298                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 299                                 "out of range\n",
 300                        sb->s_id, ino);
 301                 iget_failed(inode);
 302                 return ERR_PTR(-EIO);
 303         }
 304         block = ino / QNX4_INODES_PER_BLOCK;
 305
 306         if (!(bh = sb_bread(sb, block))) {
 307                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 308                        "%s\n", sb->s_id);
 309                 iget_failed(inode);
 310                 return ERR_PTR(-EIO);
 311         }
 312         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 313             (ino % QNX4_INODES_PER_BLOCK);
 314
 315         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 316         i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
 317         i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
 318         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 319         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 320         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 321         inode->i_mtime.tv_nsec = 0;
 322         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 323         inode->i_atime.tv_nsec = 0;
 324         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 325         inode->i_ctime.tv_nsec = 0;
 326         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 327
 328         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 329         if (S_ISREG(inode->i_mode)) {
 330                 inode->i_fop = &generic_ro_fops;
 331                 inode->i_mapping->a_ops = &qnx4_aops;
 332                 qnx4_i(inode)->mmu_private = inode->i_size;
 333         } else if (S_ISDIR(inode->i_mode)) {
 334                 inode->i_op = &qnx4_dir_inode_operations;
 335                 inode->i_fop = &qnx4_dir_operations;
 336         } else if (S_ISLNK(inode->i_mode)) {
 337                 inode->i_op = &page_symlink_inode_operations;
 338                 inode->i_mapping->a_ops = &qnx4_aops;
 339                 qnx4_i(inode)->mmu_private = inode->i_size;
 340         } else {
 341                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 342                         ino, sb->s_id);
 343                 iget_failed(inode);
 344                 brelse(bh);
 345                 return ERR_PTR(-EIO);
 346         }
 347         brelse(bh);
 348         unlock_new_inode(inode);
 349         return inode;
 350 }
 351
 352 static struct kmem_cache *qnx4_inode_cachep;
 353
 354 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 355 {
 356         struct qnx4_inode_info *ei;
 357         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 358         if (!ei)
 359                 return NULL;
 360         return &ei->vfs_inode;
 361 }
 362
 363 static void qnx4_i_callback(struct rcu_head *head)
 364 {
 365         struct inode *inode = container_of(head, struct inode, i_rcu);
 366         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 367 }
 368
 369 static void qnx4_destroy_inode(struct inode *inode)
 370 {
 371         call_rcu(&inode->i_rcu, qnx4_i_callback);
 372 }
 373
 374 static void init_once(void *foo)
 375 {
 376         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 377
 378         inode_init_once(&ei->vfs_inode);
 379 }
 380
 381 static int init_inodecache(void)
 382 {
 383         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 384                                              sizeof(struct qnx4_inode_info),
 385                                              0, (SLAB_RECLAIM_ACCOUNT|
 386                                                 SLAB_MEM_SPREAD),
 387                                              init_once);
 388         if (qnx4_inode_cachep == NULL)
 389                 return -ENOMEM;
 390         return 0;
 391 }
 392
 393 static void destroy_inodecache(void)
 394 {
 395         /*
 396          * Make sure all delayed rcu free inodes are flushed before we
 397          * destroy cache.
 398          */
 399         rcu_barrier();
 400         kmem_cache_destroy(qnx4_inode_cachep);
 401 }
 402
 403 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 404         int flags, const char *dev_name, void *data)
 405 {
 406         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 407 }
 408
 409 static struct file_system_type qnx4_fs_type = {
 410         .owner          = THIS_MODULE,
 411         .name           = "qnx4",
 412         .mount          = qnx4_mount,
 413         .kill_sb        = kill_block_super,
 414         .fs_flags       = FS_REQUIRES_DEV,
 415 };
 416 MODULE_ALIAS_FS("qnx4");
 417
 418 static int __init init_qnx4_fs(void)
 419 {
 420         int err;
 421
 422         err = init_inodecache();
 423         if (err)
 424                 return err;
 425
 426         err = register_filesystem(&qnx4_fs_type);
 427         if (err) {
 428                 destroy_inodecache();
 429                 return err;
 430         }
 431
 432         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 433         return 0;
 434 }
 435
 436 static void __exit exit_qnx4_fs(void)
 437 {
 438         unregister_filesystem(&qnx4_fs_type);
 439         destroy_inodecache();
 440 }
 441
 442 module_init(init_qnx4_fs)
 443 module_exit(exit_qnx4_fs)
 444 MODULE_LICENSE("GPL");
 445