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
  17 #include "hfs_fs.h"
  18 #include "btree.h"
  19
  20 static struct file_operations hfs_file_operations;
  21 static struct inode_operations hfs_file_inode_operations;
  22
  23 /*================ Variable-like macros ================*/
  24
  25 #define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  26
  27 static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  28 {
  29         return block_write_full_page(page, hfs_get_block, wbc);
  30 }
  31
  32 static int hfs_readpage(struct file *file, struct page *page)
  33 {
  34         return block_read_full_page(page, hfs_get_block);
  35 }
  36
  37 static int hfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
  38 {
  39         return cont_prepare_write(page, from, to, hfs_get_block,
  40                                   &HFS_I(page->mapping->host)->phys_size);
  41 }
  42
  43 static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  44 {
  45         return generic_block_bmap(mapping, block, hfs_get_block);
  46 }
  47
  48 static int hfs_releasepage(struct page *page, gfp_t mask)
  49 {
  50         struct inode *inode = page->mapping->host;
  51         struct super_block *sb = inode->i_sb;
  52         struct hfs_btree *tree;
  53         struct hfs_bnode *node;
  54         u32 nidx;
  55         int i, res = 1;
  56
  57         switch (inode->i_ino) {
  58         case HFS_EXT_CNID:
  59                 tree = HFS_SB(sb)->ext_tree;
  60                 break;
  61         case HFS_CAT_CNID:
  62                 tree = HFS_SB(sb)->cat_tree;
  63                 break;
  64         default:
  65                 BUG();
  66                 return 0;
  67         }
  68         if (tree->node_size >= PAGE_CACHE_SIZE) {
  69                 nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
  70                 spin_lock(&tree->hash_lock);
  71                 node = hfs_bnode_findhash(tree, nidx);
  72                 if (!node)
  73                         ;
  74                 else if (atomic_read(&node->refcnt))
  75                         res = 0;
  76                 if (res && node) {
  77                         hfs_bnode_unhash(node);
  78                         hfs_bnode_free(node);
  79                 }
  80                 spin_unlock(&tree->hash_lock);
  81         } else {
  82                 nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  83                 i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  84                 spin_lock(&tree->hash_lock);
  85                 do {
  86                         node = hfs_bnode_findhash(tree, nidx++);
  87                         if (!node)
  88                                 continue;
  89                         if (atomic_read(&node->refcnt)) {
  90                                 res = 0;
  91                                 break;
  92                         }
  93                         hfs_bnode_unhash(node);
  94                         hfs_bnode_free(node);
  95                 } while (--i && nidx < tree->node_count);
  96                 spin_unlock(&tree->hash_lock);
  97         }
  98         //printk("releasepage: %lu,%x = %d\n", page->index, mask, res);
  99         return res ? try_to_free_buffers(page) : 0;
 100 }
 101
 102 static int hfs_get_blocks(struct inode *inode, sector_t iblock, unsigned long max_blocks,
 103                           struct buffer_head *bh_result, int create)
 104 {
 105         int ret;
 106
 107         ret = hfs_get_block(inode, iblock, bh_result, create);
 108         if (!ret)
 109                 bh_result->b_size = (1 << inode->i_blkbits);
 110         return ret;
 111 }
 112
 113 static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 114                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 115 {
 116         struct file *file = iocb->ki_filp;
 117         struct inode *inode = file->f_dentry->d_inode->i_mapping->host;
 118
 119         return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 120                                   offset, nr_segs, hfs_get_blocks, NULL);
 121 }
 122
 123 static int hfs_writepages(struct address_space *mapping,
 124                           struct writeback_control *wbc)
 125 {
 126         return mpage_writepages(mapping, wbc, hfs_get_block);
 127 }
 128
 129 struct address_space_operations hfs_btree_aops = {
 130         .readpage       = hfs_readpage,
 131         .writepage      = hfs_writepage,
 132         .sync_page      = block_sync_page,
 133         .prepare_write  = hfs_prepare_write,
 134         .commit_write   = generic_commit_write,
 135         .bmap           = hfs_bmap,
 136         .releasepage    = hfs_releasepage,
 137 };
 138
 139 struct address_space_operations hfs_aops = {
 140         .readpage       = hfs_readpage,
 141         .writepage      = hfs_writepage,
 142         .sync_page      = block_sync_page,
 143         .prepare_write  = hfs_prepare_write,
 144         .commit_write   = generic_commit_write,
 145         .bmap           = hfs_bmap,
 146         .direct_IO      = hfs_direct_IO,
 147         .writepages     = hfs_writepages,
 148 };
 149
 150 /*
 151  * hfs_new_inode
 152  */
 153 struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, int mode)
 154 {
 155         struct super_block *sb = dir->i_sb;
 156         struct inode *inode = new_inode(sb);
 157         if (!inode)
 158                 return NULL;
 159
 160         init_MUTEX(&HFS_I(inode)->extents_lock);
 161         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 162         hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 163         inode->i_ino = HFS_SB(sb)->next_id++;
 164         inode->i_mode = mode;
 165         inode->i_uid = current->fsuid;
 166         inode->i_gid = current->fsgid;
 167         inode->i_nlink = 1;
 168         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 169         inode->i_blksize = HFS_SB(sb)->alloc_blksz;
 170         HFS_I(inode)->flags = 0;
 171         HFS_I(inode)->rsrc_inode = NULL;
 172         HFS_I(inode)->fs_blocks = 0;
 173         if (S_ISDIR(mode)) {
 174                 inode->i_size = 2;
 175                 HFS_SB(sb)->folder_count++;
 176                 if (dir->i_ino == HFS_ROOT_CNID)
 177                         HFS_SB(sb)->root_dirs++;
 178                 inode->i_op = &hfs_dir_inode_operations;
 179                 inode->i_fop = &hfs_dir_operations;
 180                 inode->i_mode |= S_IRWXUGO;
 181                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 182         } else if (S_ISREG(mode)) {
 183                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 184                 HFS_SB(sb)->file_count++;
 185                 if (dir->i_ino == HFS_ROOT_CNID)
 186                         HFS_SB(sb)->root_files++;
 187                 inode->i_op = &hfs_file_inode_operations;
 188                 inode->i_fop = &hfs_file_operations;
 189                 inode->i_mapping->a_ops = &hfs_aops;
 190                 inode->i_mode |= S_IRUGO|S_IXUGO;
 191                 if (mode & S_IWUSR)
 192                         inode->i_mode |= S_IWUGO;
 193                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 194                 HFS_I(inode)->phys_size = 0;
 195                 HFS_I(inode)->alloc_blocks = 0;
 196                 HFS_I(inode)->first_blocks = 0;
 197                 HFS_I(inode)->cached_start = 0;
 198                 HFS_I(inode)->cached_blocks = 0;
 199                 memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 200                 memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 201         }
 202         insert_inode_hash(inode);
 203         mark_inode_dirty(inode);
 204         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 205         sb->s_dirt = 1;
 206
 207         return inode;
 208 }
 209
 210 void hfs_delete_inode(struct inode *inode)
 211 {
 212         struct super_block *sb = inode->i_sb;
 213
 214         dprint(DBG_INODE, "delete_inode: %lu\n", inode->i_ino);
 215         if (S_ISDIR(inode->i_mode)) {
 216                 HFS_SB(sb)->folder_count--;
 217                 if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 218                         HFS_SB(sb)->root_dirs--;
 219                 set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 220                 sb->s_dirt = 1;
 221                 return;
 222         }
 223         HFS_SB(sb)->file_count--;
 224         if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 225                 HFS_SB(sb)->root_files--;
 226         if (S_ISREG(inode->i_mode)) {
 227                 if (!inode->i_nlink) {
 228                         inode->i_size = 0;
 229                         hfs_file_truncate(inode);
 230                 }
 231         }
 232         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 233         sb->s_dirt = 1;
 234 }
 235
 236 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 237                          __be32 __log_size, __be32 phys_size, u32 clump_size)
 238 {
 239         struct super_block *sb = inode->i_sb;
 240         u32 log_size = be32_to_cpu(__log_size);
 241         u16 count;
 242         int i;
 243
 244         memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 245         for (count = 0, i = 0; i < 3; i++)
 246                 count += be16_to_cpu(ext[i].count);
 247         HFS_I(inode)->first_blocks = count;
 248
 249         inode->i_size = HFS_I(inode)->phys_size = log_size;
 250         HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 251         inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 252         HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 253                                      HFS_SB(sb)->alloc_blksz;
 254         HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 255         if (!HFS_I(inode)->clump_blocks)
 256                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 257 }
 258
 259 struct hfs_iget_data {
 260         struct hfs_cat_key *key;
 261         hfs_cat_rec *rec;
 262 };
 263
 264 static int hfs_test_inode(struct inode *inode, void *data)
 265 {
 266         struct hfs_iget_data *idata = data;
 267         hfs_cat_rec *rec;
 268
 269         rec = idata->rec;
 270         switch (rec->type) {
 271         case HFS_CDR_DIR:
 272                 return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 273         case HFS_CDR_FIL:
 274                 return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 275         default:
 276                 BUG();
 277                 return 1;
 278         }
 279 }
 280
 281 /*
 282  * hfs_read_inode
 283  */
 284 static int hfs_read_inode(struct inode *inode, void *data)
 285 {
 286         struct hfs_iget_data *idata = data;
 287         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 288         hfs_cat_rec *rec;
 289
 290         HFS_I(inode)->flags = 0;
 291         HFS_I(inode)->rsrc_inode = NULL;
 292         init_MUTEX(&HFS_I(inode)->extents_lock);
 293         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 294
 295         /* Initialize the inode */
 296         inode->i_uid = hsb->s_uid;
 297         inode->i_gid = hsb->s_gid;
 298         inode->i_nlink = 1;
 299         inode->i_blksize = HFS_SB(inode->i_sb)->alloc_blksz;
 300
 301         if (idata->key)
 302                 HFS_I(inode)->cat_key = *idata->key;
 303         else
 304                 HFS_I(inode)->flags |= HFS_FLG_RSRC;
 305         HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 306
 307         rec = idata->rec;
 308         switch (rec->type) {
 309         case HFS_CDR_FIL:
 310                 if (!HFS_IS_RSRC(inode)) {
 311                         hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 312                                             rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 313                 } else {
 314                         hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 315                                             rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 316                 }
 317
 318                 inode->i_ino = be32_to_cpu(rec->file.FlNum);
 319                 inode->i_mode = S_IRUGO | S_IXUGO;
 320                 if (!(rec->file.Flags & HFS_FIL_LOCK))
 321                         inode->i_mode |= S_IWUGO;
 322                 inode->i_mode &= ~hsb->s_file_umask;
 323                 inode->i_mode |= S_IFREG;
 324                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 325                                 hfs_m_to_utime(rec->file.MdDat);
 326                 inode->i_op = &hfs_file_inode_operations;
 327                 inode->i_fop = &hfs_file_operations;
 328                 inode->i_mapping->a_ops = &hfs_aops;
 329                 break;
 330         case HFS_CDR_DIR:
 331                 inode->i_ino = be32_to_cpu(rec->dir.DirID);
 332                 inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 333                 HFS_I(inode)->fs_blocks = 0;
 334                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 335                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 336                                 hfs_m_to_utime(rec->dir.MdDat);
 337                 inode->i_op = &hfs_dir_inode_operations;
 338                 inode->i_fop = &hfs_dir_operations;
 339                 break;
 340         default:
 341                 make_bad_inode(inode);
 342         }
 343         return 0;
 344 }
 345
 346 /*
 347  * __hfs_iget()
 348  *
 349  * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 350  * the catalog B-tree and the 'type' of the desired file return the
 351  * inode for that file/directory or NULL.  Note that 'type' indicates
 352  * whether we want the actual file or directory, or the corresponding
 353  * metadata (AppleDouble header file or CAP metadata file).
 354  */
 355 struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 356 {
 357         struct hfs_iget_data data = { key, rec };
 358         struct inode *inode;
 359         u32 cnid;
 360
 361         switch (rec->type) {
 362         case HFS_CDR_DIR:
 363                 cnid = be32_to_cpu(rec->dir.DirID);
 364                 break;
 365         case HFS_CDR_FIL:
 366                 cnid = be32_to_cpu(rec->file.FlNum);
 367                 break;
 368         default:
 369                 return NULL;
 370         }
 371         inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 372         if (inode && (inode->i_state & I_NEW))
 373                 unlock_new_inode(inode);
 374         return inode;
 375 }
 376
 377 void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 378                           __be32 *log_size, __be32 *phys_size)
 379 {
 380         memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 381
 382         if (log_size)
 383                 *log_size = cpu_to_be32(inode->i_size);
 384         if (phys_size)
 385                 *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 386                                          HFS_SB(inode->i_sb)->alloc_blksz);
 387 }
 388
 389 int hfs_write_inode(struct inode *inode, int unused)
 390 {
 391         struct inode *main_inode = inode;
 392         struct hfs_find_data fd;
 393         hfs_cat_rec rec;
 394
 395         dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 396         hfs_ext_write_extent(inode);
 397
 398         if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 399                 switch (inode->i_ino) {
 400                 case HFS_ROOT_CNID:
 401                         break;
 402                 case HFS_EXT_CNID:
 403                         hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 404                         return 0;
 405                 case HFS_CAT_CNID:
 406                         hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 407                         return 0;
 408                 default:
 409                         BUG();
 410                         return -EIO;
 411                 }
 412         }
 413
 414         if (HFS_IS_RSRC(inode))
 415                 main_inode = HFS_I(inode)->rsrc_inode;
 416
 417         if (!main_inode->i_nlink)
 418                 return 0;
 419
 420         if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 421                 /* panic? */
 422                 return -EIO;
 423
 424         fd.search_key->cat = HFS_I(main_inode)->cat_key;
 425         if (hfs_brec_find(&fd))
 426                 /* panic? */
 427                 goto out;
 428
 429         if (S_ISDIR(main_inode->i_mode)) {
 430                 if (fd.entrylength < sizeof(struct hfs_cat_dir))
 431                         /* panic? */;
 432                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 433                            sizeof(struct hfs_cat_dir));
 434                 if (rec.type != HFS_CDR_DIR ||
 435                     be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 436                 }
 437
 438                 rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 439                 rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 440
 441                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 442                             sizeof(struct hfs_cat_dir));
 443         } else if (HFS_IS_RSRC(inode)) {
 444                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 445                                sizeof(struct hfs_cat_file));
 446                 hfs_inode_write_fork(inode, rec.file.RExtRec,
 447                                      &rec.file.RLgLen, &rec.file.RPyLen);
 448                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 449                                 sizeof(struct hfs_cat_file));
 450         } else {
 451                 if (fd.entrylength < sizeof(struct hfs_cat_file))
 452                         /* panic? */;
 453                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 454                            sizeof(struct hfs_cat_file));
 455                 if (rec.type != HFS_CDR_FIL ||
 456                     be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 457                 }
 458
 459                 if (inode->i_mode & S_IWUSR)
 460                         rec.file.Flags &= ~HFS_FIL_LOCK;
 461                 else
 462                         rec.file.Flags |= HFS_FIL_LOCK;
 463                 hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 464                 rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 465
 466                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 467                             sizeof(struct hfs_cat_file));
 468         }
 469 out:
 470         hfs_find_exit(&fd);
 471         return 0;
 472 }
 473
 474 static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 475                                       struct nameidata *nd)
 476 {
 477         struct inode *inode = NULL;
 478         hfs_cat_rec rec;
 479         struct hfs_find_data fd;
 480         int res;
 481
 482         if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 483                 goto out;
 484
 485         inode = HFS_I(dir)->rsrc_inode;
 486         if (inode)
 487                 goto out;
 488
 489         inode = new_inode(dir->i_sb);
 490         if (!inode)
 491                 return ERR_PTR(-ENOMEM);
 492
 493         hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 494         fd.search_key->cat = HFS_I(dir)->cat_key;
 495         res = hfs_brec_read(&fd, &rec, sizeof(rec));
 496         if (!res) {
 497                 struct hfs_iget_data idata = { NULL, &rec };
 498                 hfs_read_inode(inode, &idata);
 499         }
 500         hfs_find_exit(&fd);
 501         if (res) {
 502                 iput(inode);
 503                 return ERR_PTR(res);
 504         }
 505         HFS_I(inode)->rsrc_inode = dir;
 506         HFS_I(dir)->rsrc_inode = inode;
 507         igrab(dir);
 508         hlist_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
 509         mark_inode_dirty(inode);
 510 out:
 511         d_add(dentry, inode);
 512         return NULL;
 513 }
 514
 515 void hfs_clear_inode(struct inode *inode)
 516 {
 517         if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 518                 HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 519                 iput(HFS_I(inode)->rsrc_inode);
 520         }
 521 }
 522
 523 static int hfs_permission(struct inode *inode, int mask,
 524                           struct nameidata *nd)
 525 {
 526         if (S_ISREG(inode->i_mode) && mask & MAY_EXEC)
 527                 return 0;
 528         return generic_permission(inode, mask, NULL);
 529 }
 530
 531 static int hfs_file_open(struct inode *inode, struct file *file)
 532 {
 533         if (HFS_IS_RSRC(inode))
 534                 inode = HFS_I(inode)->rsrc_inode;
 535         if (atomic_read(&file->f_count) != 1)
 536                 return 0;
 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_read(&file->f_count) != 0)
 548                 return 0;
 549         if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 550                 down(&inode->i_sem);
 551                 hfs_file_truncate(inode);
 552                 //if (inode->i_flags & S_DEAD) {
 553                 //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 554                 //      hfs_delete_inode(inode);
 555                 //}
 556                 up(&inode->i_sem);
 557         }
 558         return 0;
 559 }
 560
 561 /*
 562  * hfs_notify_change()
 563  *
 564  * Based very closely on fs/msdos/inode.c by Werner Almesberger
 565  *
 566  * This is the notify_change() field in the super_operations structure
 567  * for HFS file systems.  The purpose is to take that changes made to
 568  * an inode and apply then in a filesystem-dependent manner.  In this
 569  * case the process has a few of tasks to do:
 570  *  1) prevent changes to the i_uid and i_gid fields.
 571  *  2) map file permissions to the closest allowable permissions
 572  *  3) Since multiple Linux files can share the same on-disk inode under
 573  *     HFS (for instance the data and resource forks of a file) a change
 574  *     to permissions must be applied to all other in-core inodes which
 575  *     correspond to the same HFS file.
 576  */
 577
 578 int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
 579 {
 580         struct inode *inode = dentry->d_inode;
 581         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 582         int error;
 583
 584         error = inode_change_ok(inode, attr); /* basic permission checks */
 585         if (error)
 586                 return error;
 587
 588         /* no uig/gid changes and limit which mode bits can be set */
 589         if (((attr->ia_valid & ATTR_UID) &&
 590              (attr->ia_uid != hsb->s_uid)) ||
 591             ((attr->ia_valid & ATTR_GID) &&
 592              (attr->ia_gid != hsb->s_gid)) ||
 593             ((attr->ia_valid & ATTR_MODE) &&
 594              ((S_ISDIR(inode->i_mode) &&
 595                (attr->ia_mode != inode->i_mode)) ||
 596               (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 597                 return hsb->s_quiet ? 0 : error;
 598         }
 599
 600         if (attr->ia_valid & ATTR_MODE) {
 601                 /* Only the 'w' bits can ever change and only all together. */
 602                 if (attr->ia_mode & S_IWUSR)
 603                         attr->ia_mode = inode->i_mode | S_IWUGO;
 604                 else
 605                         attr->ia_mode = inode->i_mode & ~S_IWUGO;
 606                 attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 607         }
 608         error = inode_setattr(inode, attr);
 609         if (error)
 610                 return error;
 611
 612         return 0;
 613 }
 614
 615
 616 static struct file_operations hfs_file_operations = {
 617         .llseek         = generic_file_llseek,
 618         .read           = generic_file_read,
 619         .write          = generic_file_write,
 620         .mmap           = generic_file_mmap,
 621         .sendfile       = generic_file_sendfile,
 622         .fsync          = file_fsync,
 623         .open           = hfs_file_open,
 624         .release        = hfs_file_release,
 625 };
 626
 627 static struct inode_operations hfs_file_inode_operations = {
 628         .lookup         = hfs_file_lookup,
 629         .truncate       = hfs_file_truncate,
 630         .setattr        = hfs_inode_setattr,
 631         .permission     = hfs_permission,
 632         .setxattr       = hfs_setxattr,
 633         .getxattr       = hfs_getxattr,
 634         .listxattr      = hfs_listxattr,
 635 };