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