kernel/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 struct inode *qnx4_alloc_inode(struct super_block *sb);
  31 static void qnx4_destroy_inode(struct inode *inode);
  32 static int qnx4_remount(struct super_block *sb, int *flags, char *data);
  33 static int qnx4_statfs(struct dentry *, struct kstatfs *);
  34
  35 static const struct super_operations qnx4_sops =
  36 {
  37         .alloc_inode    = qnx4_alloc_inode,
  38         .destroy_inode  = qnx4_destroy_inode,
  39         .statfs         = qnx4_statfs,
  40         .remount_fs     = qnx4_remount,
  41 };
  42
  43 static int qnx4_remount(struct super_block *sb, int *flags, char *data)
  44 {
  45         struct qnx4_sb_info *qs;
  46
  47         sync_filesystem(sb);
  48         qs = qnx4_sb(sb);
  49         qs->Version = QNX4_VERSION;
  50         *flags |= MS_RDONLY;
  51         return 0;
  52 }
  53
  54 static int qnx4_get_block( struct inode *inode, sector_t iblock, struct buffer_head *bh, int create )
  55 {
  56         unsigned long phys;
  57
  58         QNX4DEBUG((KERN_INFO "qnx4: qnx4_get_block inode=[%ld] iblock=[%ld]\n",inode->i_ino,iblock));
  59
  60         phys = qnx4_block_map( inode, iblock );
  61         if ( phys ) {
  62                 // logical block is before EOF
  63                 map_bh(bh, inode->i_sb, phys);
  64         }
  65         return 0;
  66 }
  67
  68 static inline u32 try_extent(qnx4_xtnt_t *extent, u32 *offset)
  69 {
  70         u32 size = le32_to_cpu(extent->xtnt_size);
  71         if (*offset < size)
  72                 return le32_to_cpu(extent->xtnt_blk) + *offset - 1;
  73         *offset -= size;
  74         return 0;
  75 }
  76
  77 unsigned long qnx4_block_map( struct inode *inode, long iblock )
  78 {
  79         int ix;
  80         long i_xblk;
  81         struct buffer_head *bh = NULL;
  82         struct qnx4_xblk *xblk = NULL;
  83         struct qnx4_inode_entry *qnx4_inode = qnx4_raw_inode(inode);
  84         u16 nxtnt = le16_to_cpu(qnx4_inode->di_num_xtnts);
  85         u32 offset = iblock;
  86         u32 block = try_extent(&qnx4_inode->di_first_xtnt, &offset);
  87
  88         if (block) {
  89                 // iblock is in the first extent. This is easy.
  90         } else {
  91                 // iblock is beyond first extent. We have to follow the extent chain.
  92                 i_xblk = le32_to_cpu(qnx4_inode->di_xblk);
  93                 ix = 0;
  94                 while ( --nxtnt > 0 ) {
  95                         if ( ix == 0 ) {
  96                                 // read next xtnt block.
  97                                 bh = sb_bread(inode->i_sb, i_xblk - 1);
  98                                 if ( !bh ) {
  99                                         QNX4DEBUG((KERN_ERR "qnx4: I/O error reading xtnt block [%ld])\n", i_xblk - 1));
 100                                         return -EIO;
 101                                 }
 102                                 xblk = (struct qnx4_xblk*)bh->b_data;
 103                                 if ( memcmp( xblk->xblk_signature, "IamXblk", 7 ) ) {
 104                                         QNX4DEBUG((KERN_ERR "qnx4: block at %ld is not a valid xtnt\n", qnx4_inode->i_xblk));
 105                                         return -EIO;
 106                                 }
 107                         }
 108                         block = try_extent(&xblk->xblk_xtnts[ix], &offset);
 109                         if (block) {
 110                                 // got it!
 111                                 break;
 112                         }
 113                         if ( ++ix >= xblk->xblk_num_xtnts ) {
 114                                 i_xblk = le32_to_cpu(xblk->xblk_next_xblk);
 115                                 ix = 0;
 116                                 brelse( bh );
 117                                 bh = NULL;
 118                         }
 119                 }
 120                 if ( bh )
 121                         brelse( bh );
 122         }
 123
 124         QNX4DEBUG((KERN_INFO "qnx4: mapping block %ld of inode %ld = %ld\n",iblock,inode->i_ino,block));
 125         return block;
 126 }
 127
 128 static int qnx4_statfs(struct dentry *dentry, struct kstatfs *buf)
 129 {
 130         struct super_block *sb = dentry->d_sb;
 131         u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
 132
 133         buf->f_type    = sb->s_magic;
 134         buf->f_bsize   = sb->s_blocksize;
 135         buf->f_blocks  = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size) * 8;
 136         buf->f_bfree   = qnx4_count_free_blocks(sb);
 137         buf->f_bavail  = buf->f_bfree;
 138         buf->f_namelen = QNX4_NAME_MAX;
 139         buf->f_fsid.val[0] = (u32)id;
 140         buf->f_fsid.val[1] = (u32)(id >> 32);
 141
 142         return 0;
 143 }
 144
 145 /*
 146  * Check the root directory of the filesystem to make sure
 147  * it really _is_ a qnx4 filesystem, and to check the size
 148  * of the directory entry.
 149  */
 150 static const char *qnx4_checkroot(struct super_block *sb,
 151                                   struct qnx4_super_block *s)
 152 {
 153         struct buffer_head *bh;
 154         struct qnx4_inode_entry *rootdir;
 155         int rd, rl;
 156         int i, j;
 157
 158         if (s->RootDir.di_fname[0] != '/' || s->RootDir.di_fname[1] != '\0')
 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(s->RootDir.di_first_xtnt.xtnt_blk) - 1;
 162         rl = le32_to_cpu(s->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
 193         qs = kzalloc(sizeof(struct qnx4_sb_info), GFP_KERNEL);
 194         if (!qs)
 195                 return -ENOMEM;
 196         s->s_fs_info = qs;
 197
 198         sb_set_blocksize(s, QNX4_BLOCK_SIZE);
 199
 200         s->s_op = &qnx4_sops;
 201         s->s_magic = QNX4_SUPER_MAGIC;
 202         s->s_flags |= MS_RDONLY;        /* Yup, read-only yet */
 203
 204         /* Check the superblock signature. Since the qnx4 code is
 205            dangerous, we should leave as quickly as possible
 206            if we don't belong here... */
 207         bh = sb_bread(s, 1);
 208         if (!bh) {
 209                 printk(KERN_ERR "qnx4: unable to read the superblock\n");
 210                 return -EINVAL;
 211         }
 212
 213         /* check before allocating dentries, inodes, .. */
 214         errmsg = qnx4_checkroot(s, (struct qnx4_super_block *) bh->b_data);
 215         brelse(bh);
 216         if (errmsg != NULL) {
 217                 if (!silent)
 218                         printk(KERN_ERR "qnx4: %s\n", errmsg);
 219                 return -EINVAL;
 220         }
 221
 222         /* does root not have inode number QNX4_ROOT_INO ?? */
 223         root = qnx4_iget(s, QNX4_ROOT_INO * QNX4_INODES_PER_BLOCK);
 224         if (IS_ERR(root)) {
 225                 printk(KERN_ERR "qnx4: get inode failed\n");
 226                 return PTR_ERR(root);
 227         }
 228
 229         s->s_root = d_make_root(root);
 230         if (s->s_root == NULL)
 231                 return -ENOMEM;
 232
 233         return 0;
 234 }
 235
 236 static void qnx4_kill_sb(struct super_block *sb)
 237 {
 238         struct qnx4_sb_info *qs = qnx4_sb(sb);
 239         kill_block_super(sb);
 240         if (qs) {
 241                 kfree(qs->BitMap);
 242                 kfree(qs);
 243         }
 244 }
 245
 246 static int qnx4_readpage(struct file *file, struct page *page)
 247 {
 248         return block_read_full_page(page,qnx4_get_block);
 249 }
 250
 251 static sector_t qnx4_bmap(struct address_space *mapping, sector_t block)
 252 {
 253         return generic_block_bmap(mapping,block,qnx4_get_block);
 254 }
 255 static const struct address_space_operations qnx4_aops = {
 256         .readpage       = qnx4_readpage,
 257         .bmap           = qnx4_bmap
 258 };
 259
 260 struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 261 {
 262         struct buffer_head *bh;
 263         struct qnx4_inode_entry *raw_inode;
 264         int block;
 265         struct qnx4_inode_entry *qnx4_inode;
 266         struct inode *inode;
 267
 268         inode = iget_locked(sb, ino);
 269         if (!inode)
 270                 return ERR_PTR(-ENOMEM);
 271         if (!(inode->i_state & I_NEW))
 272                 return inode;
 273
 274         qnx4_inode = qnx4_raw_inode(inode);
 275         inode->i_mode = 0;
 276
 277         QNX4DEBUG((KERN_INFO "reading inode : [%d]\n", ino));
 278         if (!ino) {
 279                 printk(KERN_ERR "qnx4: bad inode number on dev %s: %lu is "
 280                                 "out of range\n",
 281                        sb->s_id, ino);
 282                 iget_failed(inode);
 283                 return ERR_PTR(-EIO);
 284         }
 285         block = ino / QNX4_INODES_PER_BLOCK;
 286
 287         if (!(bh = sb_bread(sb, block))) {
 288                 printk(KERN_ERR "qnx4: major problem: unable to read inode from dev "
 289                        "%s\n", sb->s_id);
 290                 iget_failed(inode);
 291                 return ERR_PTR(-EIO);
 292         }
 293         raw_inode = ((struct qnx4_inode_entry *) bh->b_data) +
 294             (ino % QNX4_INODES_PER_BLOCK);
 295
 296         inode->i_mode    = le16_to_cpu(raw_inode->di_mode);
 297         i_uid_write(inode, (uid_t)le16_to_cpu(raw_inode->di_uid));
 298         i_gid_write(inode, (gid_t)le16_to_cpu(raw_inode->di_gid));
 299         set_nlink(inode, le16_to_cpu(raw_inode->di_nlink));
 300         inode->i_size    = le32_to_cpu(raw_inode->di_size);
 301         inode->i_mtime.tv_sec   = le32_to_cpu(raw_inode->di_mtime);
 302         inode->i_mtime.tv_nsec = 0;
 303         inode->i_atime.tv_sec   = le32_to_cpu(raw_inode->di_atime);
 304         inode->i_atime.tv_nsec = 0;
 305         inode->i_ctime.tv_sec   = le32_to_cpu(raw_inode->di_ctime);
 306         inode->i_ctime.tv_nsec = 0;
 307         inode->i_blocks  = le32_to_cpu(raw_inode->di_first_xtnt.xtnt_size);
 308
 309         memcpy(qnx4_inode, raw_inode, QNX4_DIR_ENTRY_SIZE);
 310         if (S_ISREG(inode->i_mode)) {
 311                 inode->i_fop = &generic_ro_fops;
 312                 inode->i_mapping->a_ops = &qnx4_aops;
 313                 qnx4_i(inode)->mmu_private = inode->i_size;
 314         } else if (S_ISDIR(inode->i_mode)) {
 315                 inode->i_op = &qnx4_dir_inode_operations;
 316                 inode->i_fop = &qnx4_dir_operations;
 317         } else if (S_ISLNK(inode->i_mode)) {
 318                 inode->i_op = &page_symlink_inode_operations;
 319                 inode->i_mapping->a_ops = &qnx4_aops;
 320                 qnx4_i(inode)->mmu_private = inode->i_size;
 321         } else {
 322                 printk(KERN_ERR "qnx4: bad inode %lu on dev %s\n",
 323                         ino, sb->s_id);
 324                 iget_failed(inode);
 325                 brelse(bh);
 326                 return ERR_PTR(-EIO);
 327         }
 328         brelse(bh);
 329         unlock_new_inode(inode);
 330         return inode;
 331 }
 332
 333 static struct kmem_cache *qnx4_inode_cachep;
 334
 335 static struct inode *qnx4_alloc_inode(struct super_block *sb)
 336 {
 337         struct qnx4_inode_info *ei;
 338         ei = kmem_cache_alloc(qnx4_inode_cachep, GFP_KERNEL);
 339         if (!ei)
 340                 return NULL;
 341         return &ei->vfs_inode;
 342 }
 343
 344 static void qnx4_i_callback(struct rcu_head *head)
 345 {
 346         struct inode *inode = container_of(head, struct inode, i_rcu);
 347         kmem_cache_free(qnx4_inode_cachep, qnx4_i(inode));
 348 }
 349
 350 static void qnx4_destroy_inode(struct inode *inode)
 351 {
 352         call_rcu(&inode->i_rcu, qnx4_i_callback);
 353 }
 354
 355 static void init_once(void *foo)
 356 {
 357         struct qnx4_inode_info *ei = (struct qnx4_inode_info *) foo;
 358
 359         inode_init_once(&ei->vfs_inode);
 360 }
 361
 362 static int init_inodecache(void)
 363 {
 364         qnx4_inode_cachep = kmem_cache_create("qnx4_inode_cache",
 365                                              sizeof(struct qnx4_inode_info),
 366                                              0, (SLAB_RECLAIM_ACCOUNT|
 367                                                 SLAB_MEM_SPREAD),
 368                                              init_once);
 369         if (qnx4_inode_cachep == NULL)
 370                 return -ENOMEM;
 371         return 0;
 372 }
 373
 374 static void destroy_inodecache(void)
 375 {
 376         /*
 377          * Make sure all delayed rcu free inodes are flushed before we
 378          * destroy cache.
 379          */
 380         rcu_barrier();
 381         kmem_cache_destroy(qnx4_inode_cachep);
 382 }
 383
 384 static struct dentry *qnx4_mount(struct file_system_type *fs_type,
 385         int flags, const char *dev_name, void *data)
 386 {
 387         return mount_bdev(fs_type, flags, dev_name, data, qnx4_fill_super);
 388 }
 389
 390 static struct file_system_type qnx4_fs_type = {
 391         .owner          = THIS_MODULE,
 392         .name           = "qnx4",
 393         .mount          = qnx4_mount,
 394         .kill_sb        = qnx4_kill_sb,
 395         .fs_flags       = FS_REQUIRES_DEV,
 396 };
 397 MODULE_ALIAS_FS("qnx4");
 398
 399 static int __init init_qnx4_fs(void)
 400 {
 401         int err;
 402
 403         err = init_inodecache();
 404         if (err)
 405                 return err;
 406
 407         err = register_filesystem(&qnx4_fs_type);
 408         if (err) {
 409                 destroy_inodecache();
 410                 return err;
 411         }
 412
 413         printk(KERN_INFO "QNX4 filesystem 0.2.3 registered.\n");
 414         return 0;
 415 }
 416
 417 static void __exit exit_qnx4_fs(void)
 418 {
 419         unregister_filesystem(&qnx4_fs_type);
 420         destroy_inodecache();
 421 }
 422
 423 module_init(init_qnx4_fs)
 424 module_exit(exit_qnx4_fs)
 425 MODULE_LICENSE("GPL");
 426