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/mpage.h>
  16 #include <linux/sched.h>
  17
  18 #include "hfs_fs.h"
  19 #include "btree.h"
  20
  21 static const struct file_operations hfs_file_operations;
  22 static const struct inode_operations hfs_file_inode_operations;
  23
  24 /*================ Variable-like macros ================*/
  25
  26 #define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  27
  28 static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  29 {
  30         return block_write_full_page(page, hfs_get_block, wbc);
  31 }
  32
  33 static int hfs_readpage(struct file *file, struct page *page)
  34 {
  35         return block_read_full_page(page, hfs_get_block);
  36 }
  37
  38 static int hfs_write_begin(struct file *file, struct address_space *mapping,
  39                         loff_t pos, unsigned len, unsigned flags,
  40                         struct page **pagep, void **fsdata)
  41 {
  42         *pagep = NULL;
  43         return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
  44                                 hfs_get_block,
  45                                 &HFS_I(mapping->host)->phys_size);
  46 }
  47
  48 static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  49 {
  50         return generic_block_bmap(mapping, block, hfs_get_block);
  51 }
  52
  53 static int hfs_releasepage(struct page *page, gfp_t mask)
  54 {
  55         struct inode *inode = page->mapping->host;
  56         struct super_block *sb = inode->i_sb;
  57         struct hfs_btree *tree;
  58         struct hfs_bnode *node;
  59         u32 nidx;
  60         int i, res = 1;
  61
  62         switch (inode->i_ino) {
  63         case HFS_EXT_CNID:
  64                 tree = HFS_SB(sb)->ext_tree;
  65                 break;
  66         case HFS_CAT_CNID:
  67                 tree = HFS_SB(sb)->cat_tree;
  68                 break;
  69         default:
  70                 BUG();
  71                 return 0;
  72         }
  73
  74         if (!tree)
  75                 return 0;
  76
  77         if (tree->node_size >= PAGE_CACHE_SIZE) {
  78                 nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
  79                 spin_lock(&tree->hash_lock);
  80                 node = hfs_bnode_findhash(tree, nidx);
  81                 if (!node)
  82                         ;
  83                 else if (atomic_read(&node->refcnt))
  84                         res = 0;
  85                 if (res && node) {
  86                         hfs_bnode_unhash(node);
  87                         hfs_bnode_free(node);
  88                 }
  89                 spin_unlock(&tree->hash_lock);
  90         } else {
  91                 nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  92                 i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  93                 spin_lock(&tree->hash_lock);
  94                 do {
  95                         node = hfs_bnode_findhash(tree, nidx++);
  96                         if (!node)
  97                                 continue;
  98                         if (atomic_read(&node->refcnt)) {
  99                                 res = 0;
 100                                 break;
 101                         }
 102                         hfs_bnode_unhash(node);
 103                         hfs_bnode_free(node);
 104                 } while (--i && nidx < tree->node_count);
 105                 spin_unlock(&tree->hash_lock);
 106         }
 107         return res ? try_to_free_buffers(page) : 0;
 108 }
 109
 110 static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 111                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 112 {
 113         struct file *file = iocb->ki_filp;
 114         struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;
 115         ssize_t ret;
 116
 117         ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 118                                   offset, nr_segs, hfs_get_block, NULL);
 119
 120         /*
 121          * In case of error extending write may have instantiated a few
 122          * blocks outside i_size. Trim these off again.
 123          */
 124         if (unlikely((rw & WRITE) && ret < 0)) {
 125                 loff_t isize = i_size_read(inode);
 126                 loff_t end = offset + iov_length(iov, nr_segs);
 127
 128                 if (end > isize)
 129                         vmtruncate(inode, isize);
 130         }
 131
 132         return ret;
 133 }
 134
 135 static int hfs_writepages(struct address_space *mapping,
 136                           struct writeback_control *wbc)
 137 {
 138         return mpage_writepages(mapping, wbc, hfs_get_block);
 139 }
 140
 141 const struct address_space_operations hfs_btree_aops = {
 142         .readpage       = hfs_readpage,
 143         .writepage      = hfs_writepage,
 144         .sync_page      = block_sync_page,
 145         .write_begin    = hfs_write_begin,
 146         .write_end      = generic_write_end,
 147         .bmap           = hfs_bmap,
 148         .releasepage    = hfs_releasepage,
 149 };
 150
 151 const struct address_space_operations hfs_aops = {
 152         .readpage       = hfs_readpage,
 153         .writepage      = hfs_writepage,
 154         .sync_page      = block_sync_page,
 155         .write_begin    = hfs_write_begin,
 156         .write_end      = generic_write_end,
 157         .bmap           = hfs_bmap,
 158         .direct_IO      = hfs_direct_IO,
 159         .writepages     = hfs_writepages,
 160 };
 161
 162 /*
 163  * hfs_new_inode
 164  */
 165 struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, int mode)
 166 {
 167         struct super_block *sb = dir->i_sb;
 168         struct inode *inode = new_inode(sb);
 169         if (!inode)
 170                 return NULL;
 171
 172         mutex_init(&HFS_I(inode)->extents_lock);
 173         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 174         hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 175         inode->i_ino = HFS_SB(sb)->next_id++;
 176         inode->i_mode = mode;
 177         inode->i_uid = current_fsuid();
 178         inode->i_gid = current_fsgid();
 179         inode->i_nlink = 1;
 180         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 181         HFS_I(inode)->flags = 0;
 182         HFS_I(inode)->rsrc_inode = NULL;
 183         HFS_I(inode)->fs_blocks = 0;
 184         if (S_ISDIR(mode)) {
 185                 inode->i_size = 2;
 186                 HFS_SB(sb)->folder_count++;
 187                 if (dir->i_ino == HFS_ROOT_CNID)
 188                         HFS_SB(sb)->root_dirs++;
 189                 inode->i_op = &hfs_dir_inode_operations;
 190                 inode->i_fop = &hfs_dir_operations;
 191                 inode->i_mode |= S_IRWXUGO;
 192                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 193         } else if (S_ISREG(mode)) {
 194                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 195                 HFS_SB(sb)->file_count++;
 196                 if (dir->i_ino == HFS_ROOT_CNID)
 197                         HFS_SB(sb)->root_files++;
 198                 inode->i_op = &hfs_file_inode_operations;
 199                 inode->i_fop = &hfs_file_operations;
 200                 inode->i_mapping->a_ops = &hfs_aops;
 201                 inode->i_mode |= S_IRUGO|S_IXUGO;
 202                 if (mode & S_IWUSR)
 203                         inode->i_mode |= S_IWUGO;
 204                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 205                 HFS_I(inode)->phys_size = 0;
 206                 HFS_I(inode)->alloc_blocks = 0;
 207                 HFS_I(inode)->first_blocks = 0;
 208                 HFS_I(inode)->cached_start = 0;
 209                 HFS_I(inode)->cached_blocks = 0;
 210                 memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 211                 memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 212         }
 213         insert_inode_hash(inode);
 214         mark_inode_dirty(inode);
 215         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 216         sb->s_dirt = 1;
 217
 218         return inode;
 219 }
 220
 221 void hfs_delete_inode(struct inode *inode)
 222 {
 223         struct super_block *sb = inode->i_sb;
 224
 225         dprint(DBG_INODE, "delete_inode: %lu\n", inode->i_ino);
 226         if (S_ISDIR(inode->i_mode)) {
 227                 HFS_SB(sb)->folder_count--;
 228                 if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 229                         HFS_SB(sb)->root_dirs--;
 230                 set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 231                 sb->s_dirt = 1;
 232                 return;
 233         }
 234         HFS_SB(sb)->file_count--;
 235         if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 236                 HFS_SB(sb)->root_files--;
 237         if (S_ISREG(inode->i_mode)) {
 238                 if (!inode->i_nlink) {
 239                         inode->i_size = 0;
 240                         hfs_file_truncate(inode);
 241                 }
 242         }
 243         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 244         sb->s_dirt = 1;
 245 }
 246
 247 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 248                          __be32 __log_size, __be32 phys_size, u32 clump_size)
 249 {
 250         struct super_block *sb = inode->i_sb;
 251         u32 log_size = be32_to_cpu(__log_size);
 252         u16 count;
 253         int i;
 254
 255         memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 256         for (count = 0, i = 0; i < 3; i++)
 257                 count += be16_to_cpu(ext[i].count);
 258         HFS_I(inode)->first_blocks = count;
 259
 260         inode->i_size = HFS_I(inode)->phys_size = log_size;
 261         HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 262         inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 263         HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 264                                      HFS_SB(sb)->alloc_blksz;
 265         HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 266         if (!HFS_I(inode)->clump_blocks)
 267                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 268 }
 269
 270 struct hfs_iget_data {
 271         struct hfs_cat_key *key;
 272         hfs_cat_rec *rec;
 273 };
 274
 275 static int hfs_test_inode(struct inode *inode, void *data)
 276 {
 277         struct hfs_iget_data *idata = data;
 278         hfs_cat_rec *rec;
 279
 280         rec = idata->rec;
 281         switch (rec->type) {
 282         case HFS_CDR_DIR:
 283                 return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 284         case HFS_CDR_FIL:
 285                 return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 286         default:
 287                 BUG();
 288                 return 1;
 289         }
 290 }
 291
 292 /*
 293  * hfs_read_inode
 294  */
 295 static int hfs_read_inode(struct inode *inode, void *data)
 296 {
 297         struct hfs_iget_data *idata = data;
 298         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 299         hfs_cat_rec *rec;
 300
 301         HFS_I(inode)->flags = 0;
 302         HFS_I(inode)->rsrc_inode = NULL;
 303         mutex_init(&HFS_I(inode)->extents_lock);
 304         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 305
 306         /* Initialize the inode */
 307         inode->i_uid = hsb->s_uid;
 308         inode->i_gid = hsb->s_gid;
 309         inode->i_nlink = 1;
 310
 311         if (idata->key)
 312                 HFS_I(inode)->cat_key = *idata->key;
 313         else
 314                 HFS_I(inode)->flags |= HFS_FLG_RSRC;
 315         HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 316
 317         rec = idata->rec;
 318         switch (rec->type) {
 319         case HFS_CDR_FIL:
 320                 if (!HFS_IS_RSRC(inode)) {
 321                         hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 322                                             rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 323                 } else {
 324                         hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 325                                             rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 326                 }
 327
 328                 inode->i_ino = be32_to_cpu(rec->file.FlNum);
 329                 inode->i_mode = S_IRUGO | S_IXUGO;
 330                 if (!(rec->file.Flags & HFS_FIL_LOCK))
 331                         inode->i_mode |= S_IWUGO;
 332                 inode->i_mode &= ~hsb->s_file_umask;
 333                 inode->i_mode |= S_IFREG;
 334                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 335                                 hfs_m_to_utime(rec->file.MdDat);
 336                 inode->i_op = &hfs_file_inode_operations;
 337                 inode->i_fop = &hfs_file_operations;
 338                 inode->i_mapping->a_ops = &hfs_aops;
 339                 break;
 340         case HFS_CDR_DIR:
 341                 inode->i_ino = be32_to_cpu(rec->dir.DirID);
 342                 inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 343                 HFS_I(inode)->fs_blocks = 0;
 344                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 345                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 346                                 hfs_m_to_utime(rec->dir.MdDat);
 347                 inode->i_op = &hfs_dir_inode_operations;
 348                 inode->i_fop = &hfs_dir_operations;
 349                 break;
 350         default:
 351                 make_bad_inode(inode);
 352         }
 353         return 0;
 354 }
 355
 356 /*
 357  * __hfs_iget()
 358  *
 359  * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 360  * the catalog B-tree and the 'type' of the desired file return the
 361  * inode for that file/directory or NULL.  Note that 'type' indicates
 362  * whether we want the actual file or directory, or the corresponding
 363  * metadata (AppleDouble header file or CAP metadata file).
 364  */
 365 struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 366 {
 367         struct hfs_iget_data data = { key, rec };
 368         struct inode *inode;
 369         u32 cnid;
 370
 371         switch (rec->type) {
 372         case HFS_CDR_DIR:
 373                 cnid = be32_to_cpu(rec->dir.DirID);
 374                 break;
 375         case HFS_CDR_FIL:
 376                 cnid = be32_to_cpu(rec->file.FlNum);
 377                 break;
 378         default:
 379                 return NULL;
 380         }
 381         inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 382         if (inode && (inode->i_state & I_NEW))
 383                 unlock_new_inode(inode);
 384         return inode;
 385 }
 386
 387 void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 388                           __be32 *log_size, __be32 *phys_size)
 389 {
 390         memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 391
 392         if (log_size)
 393                 *log_size = cpu_to_be32(inode->i_size);
 394         if (phys_size)
 395                 *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 396                                          HFS_SB(inode->i_sb)->alloc_blksz);
 397 }
 398
 399 int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 400 {
 401         struct inode *main_inode = inode;
 402         struct hfs_find_data fd;
 403         hfs_cat_rec rec;
 404
 405         dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 406         hfs_ext_write_extent(inode);
 407
 408         if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 409                 switch (inode->i_ino) {
 410                 case HFS_ROOT_CNID:
 411                         break;
 412                 case HFS_EXT_CNID:
 413                         hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 414                         return 0;
 415                 case HFS_CAT_CNID:
 416                         hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 417                         return 0;
 418                 default:
 419                         BUG();
 420                         return -EIO;
 421                 }
 422         }
 423
 424         if (HFS_IS_RSRC(inode))
 425                 main_inode = HFS_I(inode)->rsrc_inode;
 426
 427         if (!main_inode->i_nlink)
 428                 return 0;
 429
 430         if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 431                 /* panic? */
 432                 return -EIO;
 433
 434         fd.search_key->cat = HFS_I(main_inode)->cat_key;
 435         if (hfs_brec_find(&fd))
 436                 /* panic? */
 437                 goto out;
 438
 439         if (S_ISDIR(main_inode->i_mode)) {
 440                 if (fd.entrylength < sizeof(struct hfs_cat_dir))
 441                         /* panic? */;
 442                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 443                            sizeof(struct hfs_cat_dir));
 444                 if (rec.type != HFS_CDR_DIR ||
 445                     be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 446                 }
 447
 448                 rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 449                 rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 450
 451                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 452                             sizeof(struct hfs_cat_dir));
 453         } else if (HFS_IS_RSRC(inode)) {
 454                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 455                                sizeof(struct hfs_cat_file));
 456                 hfs_inode_write_fork(inode, rec.file.RExtRec,
 457                                      &rec.file.RLgLen, &rec.file.RPyLen);
 458                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 459                                 sizeof(struct hfs_cat_file));
 460         } else {
 461                 if (fd.entrylength < sizeof(struct hfs_cat_file))
 462                         /* panic? */;
 463                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 464                            sizeof(struct hfs_cat_file));
 465                 if (rec.type != HFS_CDR_FIL ||
 466                     be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 467                 }
 468
 469                 if (inode->i_mode & S_IWUSR)
 470                         rec.file.Flags &= ~HFS_FIL_LOCK;
 471                 else
 472                         rec.file.Flags |= HFS_FIL_LOCK;
 473                 hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 474                 rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 475
 476                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 477                             sizeof(struct hfs_cat_file));
 478         }
 479 out:
 480         hfs_find_exit(&fd);
 481         return 0;
 482 }
 483
 484 static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 485                                       struct nameidata *nd)
 486 {
 487         struct inode *inode = NULL;
 488         hfs_cat_rec rec;
 489         struct hfs_find_data fd;
 490         int res;
 491
 492         if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 493                 goto out;
 494
 495         inode = HFS_I(dir)->rsrc_inode;
 496         if (inode)
 497                 goto out;
 498
 499         inode = new_inode(dir->i_sb);
 500         if (!inode)
 501                 return ERR_PTR(-ENOMEM);
 502
 503         hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 504         fd.search_key->cat = HFS_I(dir)->cat_key;
 505         res = hfs_brec_read(&fd, &rec, sizeof(rec));
 506         if (!res) {
 507                 struct hfs_iget_data idata = { NULL, &rec };
 508                 hfs_read_inode(inode, &idata);
 509         }
 510         hfs_find_exit(&fd);
 511         if (res) {
 512                 iput(inode);
 513                 return ERR_PTR(res);
 514         }
 515         HFS_I(inode)->rsrc_inode = dir;
 516         HFS_I(dir)->rsrc_inode = inode;
 517         igrab(dir);
 518         hlist_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
 519         mark_inode_dirty(inode);
 520 out:
 521         d_add(dentry, inode);
 522         return NULL;
 523 }
 524
 525 void hfs_clear_inode(struct inode *inode)
 526 {
 527         if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 528                 HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 529                 iput(HFS_I(inode)->rsrc_inode);
 530         }
 531 }
 532
 533 static int hfs_file_open(struct inode *inode, struct file *file)
 534 {
 535         if (HFS_IS_RSRC(inode))
 536                 inode = HFS_I(inode)->rsrc_inode;
 537         atomic_inc(&HFS_I(inode)->opencnt);
 538         return 0;
 539 }
 540
 541 static int hfs_file_release(struct inode *inode, struct file *file)
 542 {
 543         //struct super_block *sb = inode->i_sb;
 544
 545         if (HFS_IS_RSRC(inode))
 546                 inode = HFS_I(inode)->rsrc_inode;
 547         if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 548                 mutex_lock(&inode->i_mutex);
 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                 mutex_unlock(&inode->i_mutex);
 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 static const struct file_operations hfs_file_operations = {
 615         .llseek         = generic_file_llseek,
 616         .read           = do_sync_read,
 617         .aio_read       = generic_file_aio_read,
 618         .write          = do_sync_write,
 619         .aio_write      = generic_file_aio_write,
 620         .mmap           = generic_file_mmap,
 621         .splice_read    = generic_file_splice_read,
 622         .fsync          = file_fsync,
 623         .open           = hfs_file_open,
 624         .release        = hfs_file_release,
 625 };
 626
 627 static const struct inode_operations hfs_file_inode_operations = {
 628         .lookup         = hfs_file_lookup,
 629         .truncate       = hfs_file_truncate,
 630         .setattr        = hfs_inode_setattr,
 631         .setxattr       = hfs_setxattr,
 632         .getxattr       = hfs_getxattr,
 633         .listxattr      = hfs_listxattr,
 634 };