fs/hfs/inode.c

   1 /*
   2  *  linux/fs/hfs/inode.c
   3  *
   4  * Copyright (C) 1995-1997  Paul H. Hargrove
   5  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   6  * This file may be distributed under the terms of the GNU General Public License.
   7  *
   8  * This file contains inode-related functions which do not depend on
   9  * which scheme is being used to represent forks.
  10  *
  11  * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
  12  */
  13
  14 #include <linux/pagemap.h>
  15 #include <linux/version.h>
  16 #include <linux/mpage.h>
  17
  18 #include "hfs_fs.h"
  19 #include "btree.h"
  20
  21 /*================ Variable-like macros ================*/
  22
  23 #define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  24
  25 static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  26 {
  27         return block_write_full_page(page, hfs_get_block, wbc);
  28 }
  29
  30 static int hfs_readpage(struct file *file, struct page *page)
  31 {
  32         return block_read_full_page(page, hfs_get_block);
  33 }
  34
  35 static int hfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
  36 {
  37         return cont_prepare_write(page, from, to, hfs_get_block,
  38                                   &HFS_I(page->mapping->host)->phys_size);
  39 }
  40
  41 static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  42 {
  43         return generic_block_bmap(mapping, block, hfs_get_block);
  44 }
  45
  46 int hfs_releasepage(struct page *page, int mask)
  47 {
  48         struct inode *inode = page->mapping->host;
  49         struct super_block *sb = inode->i_sb;
  50         struct hfs_btree *tree;
  51         struct hfs_bnode *node;
  52         u32 nidx;
  53         int i, res = 1;
  54
  55         switch (inode->i_ino) {
  56         case HFS_EXT_CNID:
  57                 tree = HFS_SB(sb)->ext_tree;
  58                 break;
  59         case HFS_CAT_CNID:
  60                 tree = HFS_SB(sb)->cat_tree;
  61                 break;
  62         default:
  63                 BUG();
  64                 return 0;
  65         }
  66         if (tree->node_size >= PAGE_CACHE_SIZE) {
  67                 nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
  68                 spin_lock(&tree->hash_lock);
  69                 node = hfs_bnode_findhash(tree, nidx);
  70                 if (!node)
  71                         ;
  72                 else if (atomic_read(&node->refcnt))
  73                         res = 0;
  74                 else for (i = 0; i < tree->pages_per_bnode; i++) {
  75                         if (PageActive(node->page[i])) {
  76                                 res = 0;
  77                                 break;
  78                         }
  79                 }
  80                 if (res && node) {
  81                         hfs_bnode_unhash(node);
  82                         hfs_bnode_free(node);
  83                 }
  84                 spin_unlock(&tree->hash_lock);
  85         } else {
  86                 nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  87                 i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  88                 spin_lock(&tree->hash_lock);
  89                 do {
  90                         node = hfs_bnode_findhash(tree, nidx++);
  91                         if (!node)
  92                                 continue;
  93                         if (atomic_read(&node->refcnt)) {
  94                                 res = 0;
  95                                 break;
  96                         }
  97                         hfs_bnode_unhash(node);
  98                         hfs_bnode_free(node);
  99                 } while (--i && nidx < tree->node_count);
 100                 spin_unlock(&tree->hash_lock);
 101         }
 102         //printk("releasepage: %lu,%x = %d\n", page->index, mask, res);
 103         return res;
 104 }
 105
 106 static int hfs_get_blocks(struct inode *inode, sector_t iblock, unsigned long max_blocks,
 107                           struct buffer_head *bh_result, int create)
 108 {
 109         int ret;
 110
 111         ret = hfs_get_block(inode, iblock, bh_result, create);
 112         if (!ret)
 113                 bh_result->b_size = (1 << inode->i_blkbits);
 114         return ret;
 115 }
 116
 117 static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 118                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 119 {
 120         struct file *file = iocb->ki_filp;
 121         struct inode *inode = file->f_dentry->d_inode->i_mapping->host;
 122
 123         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 124                                   offset, nr_segs, hfs_get_blocks, NULL);
 125 }
 126
 127 static int hfs_writepages(struct address_space *mapping,
 128                           struct writeback_control *wbc)
 129 {
 130         return mpage_writepages(mapping, wbc, hfs_get_block);
 131 }
 132
 133 struct address_space_operations hfs_btree_aops = {
 134         .readpage       = hfs_readpage,
 135         .writepage      = hfs_writepage,
 136         .sync_page      = block_sync_page,
 137         .prepare_write  = hfs_prepare_write,
 138         .commit_write   = generic_commit_write,
 139         .bmap           = hfs_bmap,
 140         .releasepage    = hfs_releasepage,
 141 };
 142
 143 struct address_space_operations hfs_aops = {
 144         .readpage       = hfs_readpage,
 145         .writepage      = hfs_writepage,
 146         .sync_page      = block_sync_page,
 147         .prepare_write  = hfs_prepare_write,
 148         .commit_write   = generic_commit_write,
 149         .bmap           = hfs_bmap,
 150         .direct_IO      = hfs_direct_IO,
 151         .writepages     = hfs_writepages,
 152 };
 153
 154 /*
 155  * hfs_new_inode
 156  */
 157 struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, int mode)
 158 {
 159         struct super_block *sb = dir->i_sb;
 160         struct inode *inode = new_inode(sb);
 161         if (!inode)
 162                 return NULL;
 163
 164         init_MUTEX(&HFS_I(inode)->extents_lock);
 165         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 166         hfs_cat_build_key((btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 167         inode->i_ino = HFS_SB(sb)->next_id++;
 168         inode->i_mode = mode;
 169         inode->i_uid = current->fsuid;
 170         inode->i_gid = current->fsgid;
 171         inode->i_nlink = 1;
 172         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 173         inode->i_blksize = HFS_SB(sb)->alloc_blksz;
 174         HFS_I(inode)->flags = 0;
 175         HFS_I(inode)->rsrc_inode = NULL;
 176         HFS_I(inode)->fs_blocks = 0;
 177         if (S_ISDIR(inode->i_mode)) {
 178                 inode->i_size = 2;
 179                 HFS_SB(sb)->folder_count++;
 180                 if (dir->i_ino == HFS_ROOT_CNID)
 181                         HFS_SB(sb)->root_dirs++;
 182                 inode->i_op = &hfs_dir_inode_operations;
 183                 inode->i_fop = &hfs_dir_operations;
 184         } else if (S_ISREG(inode->i_mode)) {
 185                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 186                 HFS_SB(sb)->file_count++;
 187                 if (dir->i_ino == HFS_ROOT_CNID)
 188                         HFS_SB(sb)->root_files++;
 189                 inode->i_op = &hfs_file_inode_operations;
 190                 inode->i_fop = &hfs_file_operations;
 191                 inode->i_mapping->a_ops = &hfs_aops;
 192                 HFS_I(inode)->phys_size = 0;
 193                 HFS_I(inode)->alloc_blocks = 0;
 194                 HFS_I(inode)->first_blocks = 0;
 195                 HFS_I(inode)->cached_start = 0;
 196                 HFS_I(inode)->cached_blocks = 0;
 197                 memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 198                 memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 199         }
 200         insert_inode_hash(inode);
 201         mark_inode_dirty(inode);
 202         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 203         sb->s_dirt = 1;
 204
 205         return inode;
 206 }
 207
 208 void hfs_delete_inode(struct inode *inode)
 209 {
 210         struct super_block *sb = inode->i_sb;
 211
 212         dprint(DBG_INODE, "delete_inode: %lu\n", inode->i_ino);
 213         if (S_ISDIR(inode->i_mode)) {
 214                 HFS_SB(sb)->folder_count--;
 215                 if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 216                         HFS_SB(sb)->root_dirs--;
 217                 set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 218                 sb->s_dirt = 1;
 219                 return;
 220         }
 221         HFS_SB(sb)->file_count--;
 222         if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 223                 HFS_SB(sb)->root_files--;
 224         if (S_ISREG(inode->i_mode)) {
 225                 if (!inode->i_nlink) {
 226                         inode->i_size = 0;
 227                         hfs_file_truncate(inode);
 228                 }
 229         }
 230         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 231         sb->s_dirt = 1;
 232 }
 233
 234 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 235                          __be32 __log_size, __be32 phys_size, u32 clump_size)
 236 {
 237         struct super_block *sb = inode->i_sb;
 238         u32 log_size = be32_to_cpu(__log_size);
 239         u16 count;
 240         int i;
 241
 242         memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 243         for (count = 0, i = 0; i < 3; i++)
 244                 count += be16_to_cpu(ext[i].count);
 245         HFS_I(inode)->first_blocks = count;
 246
 247         inode->i_size = HFS_I(inode)->phys_size = log_size;
 248         HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 249         inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 250         HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 251                                      HFS_SB(sb)->alloc_blksz;
 252         HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 253         if (!HFS_I(inode)->clump_blocks)
 254                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 255 }
 256
 257 struct hfs_iget_data {
 258         struct hfs_cat_key *key;
 259         hfs_cat_rec *rec;
 260 };
 261
 262 int hfs_test_inode(struct inode *inode, void *data)
 263 {
 264         struct hfs_iget_data *idata = data;
 265         hfs_cat_rec *rec;
 266
 267         rec = idata->rec;
 268         switch (rec->type) {
 269         case HFS_CDR_DIR:
 270                 return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 271         case HFS_CDR_FIL:
 272                 return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 273         default:
 274                 BUG();
 275                 return 1;
 276         }
 277 }
 278
 279 /*
 280  * hfs_read_inode
 281  */
 282 int hfs_read_inode(struct inode *inode, void *data)
 283 {
 284         struct hfs_iget_data *idata = data;
 285         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 286         hfs_cat_rec *rec;
 287
 288         HFS_I(inode)->flags = 0;
 289         HFS_I(inode)->rsrc_inode = NULL;
 290         init_MUTEX(&HFS_I(inode)->extents_lock);
 291         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 292
 293         /* Initialize the inode */
 294         inode->i_uid = hsb->s_uid;
 295         inode->i_gid = hsb->s_gid;
 296         inode->i_nlink = 1;
 297         inode->i_blksize = HFS_SB(inode->i_sb)->alloc_blksz;
 298
 299         if (idata->key)
 300                 HFS_I(inode)->cat_key = *idata->key;
 301         else
 302                 HFS_I(inode)->flags |= HFS_FLG_RSRC;
 303         HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 304
 305         rec = idata->rec;
 306         switch (rec->type) {
 307         case HFS_CDR_FIL:
 308                 if (!HFS_IS_RSRC(inode)) {
 309                         hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 310                                             rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 311                 } else {
 312                         hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 313                                             rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 314                 }
 315
 316                 inode->i_ino = be32_to_cpu(rec->file.FlNum);
 317                 inode->i_mode = S_IRUGO | S_IXUGO;
 318                 if (!(rec->file.Flags & HFS_FIL_LOCK))
 319                         inode->i_mode |= S_IWUGO;
 320                 inode->i_mode &= hsb->s_file_umask;
 321                 inode->i_mode |= S_IFREG;
 322                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 323                                 hfs_m_to_utime(rec->file.MdDat);
 324                 inode->i_op = &hfs_file_inode_operations;
 325                 inode->i_fop = &hfs_file_operations;
 326                 inode->i_mapping->a_ops = &hfs_aops;
 327                 break;
 328         case HFS_CDR_DIR:
 329                 inode->i_ino = be32_to_cpu(rec->dir.DirID);
 330                 inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 331                 HFS_I(inode)->fs_blocks = 0;
 332                 inode->i_mode = S_IFDIR | (S_IRWXUGO & hsb->s_dir_umask);
 333                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 334                                 hfs_m_to_utime(rec->dir.MdDat);
 335                 inode->i_op = &hfs_dir_inode_operations;
 336                 inode->i_fop = &hfs_dir_operations;
 337                 break;
 338         default:
 339                 make_bad_inode(inode);
 340         }
 341         return 0;
 342 }
 343
 344 /*
 345  * __hfs_iget()
 346  *
 347  * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 348  * the catalog B-tree and the 'type' of the desired file return the
 349  * inode for that file/directory or NULL.  Note that 'type' indicates
 350  * whether we want the actual file or directory, or the corresponding
 351  * metadata (AppleDouble header file or CAP metadata file).
 352  */
 353 struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 354 {
 355         struct hfs_iget_data data = { key, rec };
 356         struct inode *inode;
 357         u32 cnid;
 358
 359         switch (rec->type) {
 360         case HFS_CDR_DIR:
 361                 cnid = be32_to_cpu(rec->dir.DirID);
 362                 break;
 363         case HFS_CDR_FIL:
 364                 cnid = be32_to_cpu(rec->file.FlNum);
 365                 break;
 366         default:
 367                 return NULL;
 368         }
 369         inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 370         if (inode && (inode->i_state & I_NEW))
 371                 unlock_new_inode(inode);
 372         return inode;
 373 }
 374
 375 void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 376                           __be32 *log_size, __be32 *phys_size)
 377 {
 378         memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 379
 380         if (log_size)
 381                 *log_size = cpu_to_be32(inode->i_size);
 382         if (phys_size)
 383                 *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 384                                          HFS_SB(inode->i_sb)->alloc_blksz);
 385 }
 386
 387 int hfs_write_inode(struct inode *inode, int unused)
 388 {
 389         struct inode *main_inode = inode;
 390         struct hfs_find_data fd;
 391         hfs_cat_rec rec;
 392
 393         dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 394         hfs_ext_write_extent(inode);
 395
 396         if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 397                 switch (inode->i_ino) {
 398                 case HFS_ROOT_CNID:
 399                         break;
 400                 case HFS_EXT_CNID:
 401                         hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 402                         return 0;
 403                 case HFS_CAT_CNID:
 404                         hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 405                         return 0;
 406                 default:
 407                         BUG();
 408                         return -EIO;
 409                 }
 410         }
 411
 412         if (HFS_IS_RSRC(inode))
 413                 main_inode = HFS_I(inode)->rsrc_inode;
 414
 415         if (!main_inode->i_nlink)
 416                 return 0;
 417
 418         if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 419                 /* panic? */
 420                 return -EIO;
 421
 422         fd.search_key->cat = HFS_I(main_inode)->cat_key;
 423         if (hfs_brec_find(&fd))
 424                 /* panic? */
 425                 goto out;
 426
 427         if (S_ISDIR(main_inode->i_mode)) {
 428                 if (fd.entrylength < sizeof(struct hfs_cat_dir))
 429                         /* panic? */;
 430                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 431                            sizeof(struct hfs_cat_dir));
 432                 if (rec.type != HFS_CDR_DIR ||
 433                     be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 434                 }
 435
 436                 rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 437                 rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 438
 439                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 440                             sizeof(struct hfs_cat_dir));
 441         } else if (HFS_IS_RSRC(inode)) {
 442                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 443                                sizeof(struct hfs_cat_file));
 444                 hfs_inode_write_fork(inode, rec.file.RExtRec,
 445                                      &rec.file.RLgLen, &rec.file.RPyLen);
 446                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 447                                 sizeof(struct hfs_cat_file));
 448         } else {
 449                 if (fd.entrylength < sizeof(struct hfs_cat_file))
 450                         /* panic? */;
 451                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 452                            sizeof(struct hfs_cat_file));
 453                 if (rec.type != HFS_CDR_FIL ||
 454                     be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 455                 }
 456
 457                 if (inode->i_mode & S_IWUSR)
 458                         rec.file.Flags &= ~HFS_FIL_LOCK;
 459                 else
 460                         rec.file.Flags |= HFS_FIL_LOCK;
 461                 hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 462                 rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 463
 464                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 465                             sizeof(struct hfs_cat_file));
 466         }
 467 out:
 468         hfs_find_exit(&fd);
 469         return 0;
 470 }
 471
 472 static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 473                                       struct nameidata *nd)
 474 {
 475         struct inode *inode = NULL;
 476         hfs_cat_rec rec;
 477         struct hfs_find_data fd;
 478         int res;
 479
 480         if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 481                 goto out;
 482
 483         inode = HFS_I(dir)->rsrc_inode;
 484         if (inode)
 485                 goto out;
 486
 487         inode = new_inode(dir->i_sb);
 488         if (!inode)
 489                 return ERR_PTR(-ENOMEM);
 490
 491         hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 492         fd.search_key->cat = HFS_I(dir)->cat_key;
 493         res = hfs_brec_read(&fd, &rec, sizeof(rec));
 494         if (!res) {
 495                 struct hfs_iget_data idata = { NULL, &rec };
 496                 hfs_read_inode(inode, &idata);
 497         }
 498         hfs_find_exit(&fd);
 499         if (res) {
 500                 iput(inode);
 501                 return ERR_PTR(res);
 502         }
 503         HFS_I(inode)->rsrc_inode = dir;
 504         HFS_I(dir)->rsrc_inode = inode;
 505         igrab(dir);
 506         hlist_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
 507         mark_inode_dirty(inode);
 508 out:
 509         d_add(dentry, inode);
 510         return NULL;
 511 }
 512
 513 void hfs_clear_inode(struct inode *inode)
 514 {
 515         if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 516                 HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 517                 iput(HFS_I(inode)->rsrc_inode);
 518         }
 519 }
 520
 521 static int hfs_permission(struct inode *inode, int mask,
 522                           struct nameidata *nd)
 523 {
 524         if (S_ISREG(inode->i_mode) && mask & MAY_EXEC)
 525                 return 0;
 526         return generic_permission(inode, mask, NULL);
 527 }
 528
 529 static int hfs_file_open(struct inode *inode, struct file *file)
 530 {
 531         if (HFS_IS_RSRC(inode))
 532                 inode = HFS_I(inode)->rsrc_inode;
 533         if (atomic_read(&file->f_count) != 1)
 534                 return 0;
 535         atomic_inc(&HFS_I(inode)->opencnt);
 536         return 0;
 537 }
 538
 539 static int hfs_file_release(struct inode *inode, struct file *file)
 540 {
 541         //struct super_block *sb = inode->i_sb;
 542
 543         if (HFS_IS_RSRC(inode))
 544                 inode = HFS_I(inode)->rsrc_inode;
 545         if (atomic_read(&file->f_count) != 0)
 546                 return 0;
 547         if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 548                 down(&inode->i_sem);
 549                 hfs_file_truncate(inode);
 550                 //if (inode->i_flags & S_DEAD) {
 551                 //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 552                 //      hfs_delete_inode(inode);
 553                 //}
 554                 up(&inode->i_sem);
 555         }
 556         return 0;
 557 }
 558
 559 /*
 560  * hfs_notify_change()
 561  *
 562  * Based very closely on fs/msdos/inode.c by Werner Almesberger
 563  *
 564  * This is the notify_change() field in the super_operations structure
 565  * for HFS file systems.  The purpose is to take that changes made to
 566  * an inode and apply then in a filesystem-dependent manner.  In this
 567  * case the process has a few of tasks to do:
 568  *  1) prevent changes to the i_uid and i_gid fields.
 569  *  2) map file permissions to the closest allowable permissions
 570  *  3) Since multiple Linux files can share the same on-disk inode under
 571  *     HFS (for instance the data and resource forks of a file) a change
 572  *     to permissions must be applied to all other in-core inodes which
 573  *     correspond to the same HFS file.
 574  */
 575
 576 int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
 577 {
 578         struct inode *inode = dentry->d_inode;
 579         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 580         int error;
 581
 582         error = inode_change_ok(inode, attr); /* basic permission checks */
 583         if (error)
 584                 return error;
 585
 586         /* no uig/gid changes and limit which mode bits can be set */
 587         if (((attr->ia_valid & ATTR_UID) &&
 588              (attr->ia_uid != hsb->s_uid)) ||
 589             ((attr->ia_valid & ATTR_GID) &&
 590              (attr->ia_gid != hsb->s_gid)) ||
 591             ((attr->ia_valid & ATTR_MODE) &&
 592              ((S_ISDIR(inode->i_mode) &&
 593                (attr->ia_mode != inode->i_mode)) ||
 594               (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 595                 return hsb->s_quiet ? 0 : error;
 596         }
 597
 598         if (attr->ia_valid & ATTR_MODE) {
 599                 /* Only the 'w' bits can ever change and only all together. */
 600                 if (attr->ia_mode & S_IWUSR)
 601                         attr->ia_mode = inode->i_mode | S_IWUGO;
 602                 else
 603                         attr->ia_mode = inode->i_mode & ~S_IWUGO;
 604                 attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 605         }
 606         error = inode_setattr(inode, attr);
 607         if (error)
 608                 return error;
 609
 610         return 0;
 611 }
 612
 613
 614 struct file_operations hfs_file_operations = {
 615         .llseek         = generic_file_llseek,
 616         .read           = generic_file_read,
 617         .write          = generic_file_write,
 618         .mmap           = generic_file_mmap,
 619         .sendfile       = generic_file_sendfile,
 620         .fsync          = file_fsync,
 621         .open           = hfs_file_open,
 622         .release        = hfs_file_release,
 623 };
 624
 625 struct inode_operations hfs_file_inode_operations = {
 626         .lookup         = hfs_file_lookup,
 627         .truncate       = hfs_file_truncate,
 628         .setattr        = hfs_inode_setattr,
 629         .permission     = hfs_permission,
 630         .setxattr       = hfs_setxattr,
 631         .getxattr       = hfs_getxattr,
 632         .listxattr      = hfs_listxattr,
 633 };