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         int ret;
  43
  44         *pagep = NULL;
  45         ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
  46                                 hfs_get_block,
  47                                 &HFS_I(mapping->host)->phys_size);
  48         if (unlikely(ret)) {
  49                 loff_t isize = mapping->host->i_size;
  50                 if (pos + len > isize)
  51                         vmtruncate(mapping->host, isize);
  52         }
  53
  54         return ret;
  55 }
  56
  57 static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  58 {
  59         return generic_block_bmap(mapping, block, hfs_get_block);
  60 }
  61
  62 static int hfs_releasepage(struct page *page, gfp_t mask)
  63 {
  64         struct inode *inode = page->mapping->host;
  65         struct super_block *sb = inode->i_sb;
  66         struct hfs_btree *tree;
  67         struct hfs_bnode *node;
  68         u32 nidx;
  69         int i, res = 1;
  70
  71         switch (inode->i_ino) {
  72         case HFS_EXT_CNID:
  73                 tree = HFS_SB(sb)->ext_tree;
  74                 break;
  75         case HFS_CAT_CNID:
  76                 tree = HFS_SB(sb)->cat_tree;
  77                 break;
  78         default:
  79                 BUG();
  80                 return 0;
  81         }
  82
  83         if (!tree)
  84                 return 0;
  85
  86         if (tree->node_size >= PAGE_CACHE_SIZE) {
  87                 nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
  88                 spin_lock(&tree->hash_lock);
  89                 node = hfs_bnode_findhash(tree, nidx);
  90                 if (!node)
  91                         ;
  92                 else if (atomic_read(&node->refcnt))
  93                         res = 0;
  94                 if (res && node) {
  95                         hfs_bnode_unhash(node);
  96                         hfs_bnode_free(node);
  97                 }
  98                 spin_unlock(&tree->hash_lock);
  99         } else {
 100                 nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
 101                 i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
 102                 spin_lock(&tree->hash_lock);
 103                 do {
 104                         node = hfs_bnode_findhash(tree, nidx++);
 105                         if (!node)
 106                                 continue;
 107                         if (atomic_read(&node->refcnt)) {
 108                                 res = 0;
 109                                 break;
 110                         }
 111                         hfs_bnode_unhash(node);
 112                         hfs_bnode_free(node);
 113                 } while (--i && nidx < tree->node_count);
 114                 spin_unlock(&tree->hash_lock);
 115         }
 116         return res ? try_to_free_buffers(page) : 0;
 117 }
 118
 119 static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
 120                 const struct iovec *iov, loff_t offset, unsigned long nr_segs)
 121 {
 122         struct file *file = iocb->ki_filp;
 123         struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;
 124         ssize_t ret;
 125
 126         ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
 127                                   offset, nr_segs, hfs_get_block, NULL);
 128
 129         /*
 130          * In case of error extending write may have instantiated a few
 131          * blocks outside i_size. Trim these off again.
 132          */
 133         if (unlikely((rw & WRITE) && ret < 0)) {
 134                 loff_t isize = i_size_read(inode);
 135                 loff_t end = offset + iov_length(iov, nr_segs);
 136
 137                 if (end > isize)
 138                         vmtruncate(inode, isize);
 139         }
 140
 141         return ret;
 142 }
 143
 144 static int hfs_writepages(struct address_space *mapping,
 145                           struct writeback_control *wbc)
 146 {
 147         return mpage_writepages(mapping, wbc, hfs_get_block);
 148 }
 149
 150 const struct address_space_operations hfs_btree_aops = {
 151         .readpage       = hfs_readpage,
 152         .writepage      = hfs_writepage,
 153         .sync_page      = block_sync_page,
 154         .write_begin    = hfs_write_begin,
 155         .write_end      = generic_write_end,
 156         .bmap           = hfs_bmap,
 157         .releasepage    = hfs_releasepage,
 158 };
 159
 160 const struct address_space_operations hfs_aops = {
 161         .readpage       = hfs_readpage,
 162         .writepage      = hfs_writepage,
 163         .sync_page      = block_sync_page,
 164         .write_begin    = hfs_write_begin,
 165         .write_end      = generic_write_end,
 166         .bmap           = hfs_bmap,
 167         .direct_IO      = hfs_direct_IO,
 168         .writepages     = hfs_writepages,
 169 };
 170
 171 /*
 172  * hfs_new_inode
 173  */
 174 struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, int mode)
 175 {
 176         struct super_block *sb = dir->i_sb;
 177         struct inode *inode = new_inode(sb);
 178         if (!inode)
 179                 return NULL;
 180
 181         mutex_init(&HFS_I(inode)->extents_lock);
 182         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 183         hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 184         inode->i_ino = HFS_SB(sb)->next_id++;
 185         inode->i_mode = mode;
 186         inode->i_uid = current_fsuid();
 187         inode->i_gid = current_fsgid();
 188         inode->i_nlink = 1;
 189         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 190         HFS_I(inode)->flags = 0;
 191         HFS_I(inode)->rsrc_inode = NULL;
 192         HFS_I(inode)->fs_blocks = 0;
 193         if (S_ISDIR(mode)) {
 194                 inode->i_size = 2;
 195                 HFS_SB(sb)->folder_count++;
 196                 if (dir->i_ino == HFS_ROOT_CNID)
 197                         HFS_SB(sb)->root_dirs++;
 198                 inode->i_op = &hfs_dir_inode_operations;
 199                 inode->i_fop = &hfs_dir_operations;
 200                 inode->i_mode |= S_IRWXUGO;
 201                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 202         } else if (S_ISREG(mode)) {
 203                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 204                 HFS_SB(sb)->file_count++;
 205                 if (dir->i_ino == HFS_ROOT_CNID)
 206                         HFS_SB(sb)->root_files++;
 207                 inode->i_op = &hfs_file_inode_operations;
 208                 inode->i_fop = &hfs_file_operations;
 209                 inode->i_mapping->a_ops = &hfs_aops;
 210                 inode->i_mode |= S_IRUGO|S_IXUGO;
 211                 if (mode & S_IWUSR)
 212                         inode->i_mode |= S_IWUGO;
 213                 inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 214                 HFS_I(inode)->phys_size = 0;
 215                 HFS_I(inode)->alloc_blocks = 0;
 216                 HFS_I(inode)->first_blocks = 0;
 217                 HFS_I(inode)->cached_start = 0;
 218                 HFS_I(inode)->cached_blocks = 0;
 219                 memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 220                 memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 221         }
 222         insert_inode_hash(inode);
 223         mark_inode_dirty(inode);
 224         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 225         sb->s_dirt = 1;
 226
 227         return inode;
 228 }
 229
 230 void hfs_delete_inode(struct inode *inode)
 231 {
 232         struct super_block *sb = inode->i_sb;
 233
 234         dprint(DBG_INODE, "delete_inode: %lu\n", inode->i_ino);
 235         if (S_ISDIR(inode->i_mode)) {
 236                 HFS_SB(sb)->folder_count--;
 237                 if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 238                         HFS_SB(sb)->root_dirs--;
 239                 set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 240                 sb->s_dirt = 1;
 241                 return;
 242         }
 243         HFS_SB(sb)->file_count--;
 244         if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 245                 HFS_SB(sb)->root_files--;
 246         if (S_ISREG(inode->i_mode)) {
 247                 if (!inode->i_nlink) {
 248                         inode->i_size = 0;
 249                         hfs_file_truncate(inode);
 250                 }
 251         }
 252         set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 253         sb->s_dirt = 1;
 254 }
 255
 256 void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 257                          __be32 __log_size, __be32 phys_size, u32 clump_size)
 258 {
 259         struct super_block *sb = inode->i_sb;
 260         u32 log_size = be32_to_cpu(__log_size);
 261         u16 count;
 262         int i;
 263
 264         memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 265         for (count = 0, i = 0; i < 3; i++)
 266                 count += be16_to_cpu(ext[i].count);
 267         HFS_I(inode)->first_blocks = count;
 268
 269         inode->i_size = HFS_I(inode)->phys_size = log_size;
 270         HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 271         inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 272         HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 273                                      HFS_SB(sb)->alloc_blksz;
 274         HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 275         if (!HFS_I(inode)->clump_blocks)
 276                 HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 277 }
 278
 279 struct hfs_iget_data {
 280         struct hfs_cat_key *key;
 281         hfs_cat_rec *rec;
 282 };
 283
 284 static int hfs_test_inode(struct inode *inode, void *data)
 285 {
 286         struct hfs_iget_data *idata = data;
 287         hfs_cat_rec *rec;
 288
 289         rec = idata->rec;
 290         switch (rec->type) {
 291         case HFS_CDR_DIR:
 292                 return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 293         case HFS_CDR_FIL:
 294                 return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 295         default:
 296                 BUG();
 297                 return 1;
 298         }
 299 }
 300
 301 /*
 302  * hfs_read_inode
 303  */
 304 static int hfs_read_inode(struct inode *inode, void *data)
 305 {
 306         struct hfs_iget_data *idata = data;
 307         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 308         hfs_cat_rec *rec;
 309
 310         HFS_I(inode)->flags = 0;
 311         HFS_I(inode)->rsrc_inode = NULL;
 312         mutex_init(&HFS_I(inode)->extents_lock);
 313         INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 314
 315         /* Initialize the inode */
 316         inode->i_uid = hsb->s_uid;
 317         inode->i_gid = hsb->s_gid;
 318         inode->i_nlink = 1;
 319
 320         if (idata->key)
 321                 HFS_I(inode)->cat_key = *idata->key;
 322         else
 323                 HFS_I(inode)->flags |= HFS_FLG_RSRC;
 324         HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 325
 326         rec = idata->rec;
 327         switch (rec->type) {
 328         case HFS_CDR_FIL:
 329                 if (!HFS_IS_RSRC(inode)) {
 330                         hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 331                                             rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 332                 } else {
 333                         hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 334                                             rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 335                 }
 336
 337                 inode->i_ino = be32_to_cpu(rec->file.FlNum);
 338                 inode->i_mode = S_IRUGO | S_IXUGO;
 339                 if (!(rec->file.Flags & HFS_FIL_LOCK))
 340                         inode->i_mode |= S_IWUGO;
 341                 inode->i_mode &= ~hsb->s_file_umask;
 342                 inode->i_mode |= S_IFREG;
 343                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 344                                 hfs_m_to_utime(rec->file.MdDat);
 345                 inode->i_op = &hfs_file_inode_operations;
 346                 inode->i_fop = &hfs_file_operations;
 347                 inode->i_mapping->a_ops = &hfs_aops;
 348                 break;
 349         case HFS_CDR_DIR:
 350                 inode->i_ino = be32_to_cpu(rec->dir.DirID);
 351                 inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 352                 HFS_I(inode)->fs_blocks = 0;
 353                 inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 354                 inode->i_ctime = inode->i_atime = inode->i_mtime =
 355                                 hfs_m_to_utime(rec->dir.MdDat);
 356                 inode->i_op = &hfs_dir_inode_operations;
 357                 inode->i_fop = &hfs_dir_operations;
 358                 break;
 359         default:
 360                 make_bad_inode(inode);
 361         }
 362         return 0;
 363 }
 364
 365 /*
 366  * __hfs_iget()
 367  *
 368  * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 369  * the catalog B-tree and the 'type' of the desired file return the
 370  * inode for that file/directory or NULL.  Note that 'type' indicates
 371  * whether we want the actual file or directory, or the corresponding
 372  * metadata (AppleDouble header file or CAP metadata file).
 373  */
 374 struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 375 {
 376         struct hfs_iget_data data = { key, rec };
 377         struct inode *inode;
 378         u32 cnid;
 379
 380         switch (rec->type) {
 381         case HFS_CDR_DIR:
 382                 cnid = be32_to_cpu(rec->dir.DirID);
 383                 break;
 384         case HFS_CDR_FIL:
 385                 cnid = be32_to_cpu(rec->file.FlNum);
 386                 break;
 387         default:
 388                 return NULL;
 389         }
 390         inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 391         if (inode && (inode->i_state & I_NEW))
 392                 unlock_new_inode(inode);
 393         return inode;
 394 }
 395
 396 void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 397                           __be32 *log_size, __be32 *phys_size)
 398 {
 399         memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 400
 401         if (log_size)
 402                 *log_size = cpu_to_be32(inode->i_size);
 403         if (phys_size)
 404                 *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 405                                          HFS_SB(inode->i_sb)->alloc_blksz);
 406 }
 407
 408 int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 409 {
 410         struct inode *main_inode = inode;
 411         struct hfs_find_data fd;
 412         hfs_cat_rec rec;
 413
 414         dprint(DBG_INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 415         hfs_ext_write_extent(inode);
 416
 417         if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 418                 switch (inode->i_ino) {
 419                 case HFS_ROOT_CNID:
 420                         break;
 421                 case HFS_EXT_CNID:
 422                         hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 423                         return 0;
 424                 case HFS_CAT_CNID:
 425                         hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 426                         return 0;
 427                 default:
 428                         BUG();
 429                         return -EIO;
 430                 }
 431         }
 432
 433         if (HFS_IS_RSRC(inode))
 434                 main_inode = HFS_I(inode)->rsrc_inode;
 435
 436         if (!main_inode->i_nlink)
 437                 return 0;
 438
 439         if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 440                 /* panic? */
 441                 return -EIO;
 442
 443         fd.search_key->cat = HFS_I(main_inode)->cat_key;
 444         if (hfs_brec_find(&fd))
 445                 /* panic? */
 446                 goto out;
 447
 448         if (S_ISDIR(main_inode->i_mode)) {
 449                 if (fd.entrylength < sizeof(struct hfs_cat_dir))
 450                         /* panic? */;
 451                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 452                            sizeof(struct hfs_cat_dir));
 453                 if (rec.type != HFS_CDR_DIR ||
 454                     be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 455                 }
 456
 457                 rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 458                 rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 459
 460                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 461                             sizeof(struct hfs_cat_dir));
 462         } else if (HFS_IS_RSRC(inode)) {
 463                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 464                                sizeof(struct hfs_cat_file));
 465                 hfs_inode_write_fork(inode, rec.file.RExtRec,
 466                                      &rec.file.RLgLen, &rec.file.RPyLen);
 467                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 468                                 sizeof(struct hfs_cat_file));
 469         } else {
 470                 if (fd.entrylength < sizeof(struct hfs_cat_file))
 471                         /* panic? */;
 472                 hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 473                            sizeof(struct hfs_cat_file));
 474                 if (rec.type != HFS_CDR_FIL ||
 475                     be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 476                 }
 477
 478                 if (inode->i_mode & S_IWUSR)
 479                         rec.file.Flags &= ~HFS_FIL_LOCK;
 480                 else
 481                         rec.file.Flags |= HFS_FIL_LOCK;
 482                 hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 483                 rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 484
 485                 hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 486                             sizeof(struct hfs_cat_file));
 487         }
 488 out:
 489         hfs_find_exit(&fd);
 490         return 0;
 491 }
 492
 493 static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 494                                       struct nameidata *nd)
 495 {
 496         struct inode *inode = NULL;
 497         hfs_cat_rec rec;
 498         struct hfs_find_data fd;
 499         int res;
 500
 501         if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 502                 goto out;
 503
 504         inode = HFS_I(dir)->rsrc_inode;
 505         if (inode)
 506                 goto out;
 507
 508         inode = new_inode(dir->i_sb);
 509         if (!inode)
 510                 return ERR_PTR(-ENOMEM);
 511
 512         hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 513         fd.search_key->cat = HFS_I(dir)->cat_key;
 514         res = hfs_brec_read(&fd, &rec, sizeof(rec));
 515         if (!res) {
 516                 struct hfs_iget_data idata = { NULL, &rec };
 517                 hfs_read_inode(inode, &idata);
 518         }
 519         hfs_find_exit(&fd);
 520         if (res) {
 521                 iput(inode);
 522                 return ERR_PTR(res);
 523         }
 524         HFS_I(inode)->rsrc_inode = dir;
 525         HFS_I(dir)->rsrc_inode = inode;
 526         igrab(dir);
 527         hlist_add_head(&inode->i_hash, &HFS_SB(dir->i_sb)->rsrc_inodes);
 528         mark_inode_dirty(inode);
 529 out:
 530         d_add(dentry, inode);
 531         return NULL;
 532 }
 533
 534 void hfs_evict_inode(struct inode *inode)
 535 {
 536         truncate_inode_pages(&inode->i_data, 0);
 537         end_writeback(inode);
 538         if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 539                 HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 540                 iput(HFS_I(inode)->rsrc_inode);
 541         }
 542 }
 543
 544 static int hfs_file_open(struct inode *inode, struct file *file)
 545 {
 546         if (HFS_IS_RSRC(inode))
 547                 inode = HFS_I(inode)->rsrc_inode;
 548         atomic_inc(&HFS_I(inode)->opencnt);
 549         return 0;
 550 }
 551
 552 static int hfs_file_release(struct inode *inode, struct file *file)
 553 {
 554         //struct super_block *sb = inode->i_sb;
 555
 556         if (HFS_IS_RSRC(inode))
 557                 inode = HFS_I(inode)->rsrc_inode;
 558         if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 559                 mutex_lock(&inode->i_mutex);
 560                 hfs_file_truncate(inode);
 561                 //if (inode->i_flags & S_DEAD) {
 562                 //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 563                 //      hfs_delete_inode(inode);
 564                 //}
 565                 mutex_unlock(&inode->i_mutex);
 566         }
 567         return 0;
 568 }
 569
 570 /*
 571  * hfs_notify_change()
 572  *
 573  * Based very closely on fs/msdos/inode.c by Werner Almesberger
 574  *
 575  * This is the notify_change() field in the super_operations structure
 576  * for HFS file systems.  The purpose is to take that changes made to
 577  * an inode and apply then in a filesystem-dependent manner.  In this
 578  * case the process has a few of tasks to do:
 579  *  1) prevent changes to the i_uid and i_gid fields.
 580  *  2) map file permissions to the closest allowable permissions
 581  *  3) Since multiple Linux files can share the same on-disk inode under
 582  *     HFS (for instance the data and resource forks of a file) a change
 583  *     to permissions must be applied to all other in-core inodes which
 584  *     correspond to the same HFS file.
 585  */
 586
 587 int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
 588 {
 589         struct inode *inode = dentry->d_inode;
 590         struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 591         int error;
 592
 593         error = inode_change_ok(inode, attr); /* basic permission checks */
 594         if (error)
 595                 return error;
 596
 597         /* no uig/gid changes and limit which mode bits can be set */
 598         if (((attr->ia_valid & ATTR_UID) &&
 599              (attr->ia_uid != hsb->s_uid)) ||
 600             ((attr->ia_valid & ATTR_GID) &&
 601              (attr->ia_gid != hsb->s_gid)) ||
 602             ((attr->ia_valid & ATTR_MODE) &&
 603              ((S_ISDIR(inode->i_mode) &&
 604                (attr->ia_mode != inode->i_mode)) ||
 605               (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 606                 return hsb->s_quiet ? 0 : error;
 607         }
 608
 609         if (attr->ia_valid & ATTR_MODE) {
 610                 /* Only the 'w' bits can ever change and only all together. */
 611                 if (attr->ia_mode & S_IWUSR)
 612                         attr->ia_mode = inode->i_mode | S_IWUGO;
 613                 else
 614                         attr->ia_mode = inode->i_mode & ~S_IWUGO;
 615                 attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 616         }
 617
 618         if ((attr->ia_valid & ATTR_SIZE) &&
 619             attr->ia_size != i_size_read(inode)) {
 620                 error = vmtruncate(inode, attr->ia_size);
 621                 if (error)
 622                         return error;
 623         }
 624
 625         setattr_copy(inode, attr);
 626         mark_inode_dirty(inode);
 627         return 0;
 628 }
 629
 630 static int hfs_file_fsync(struct file *filp, int datasync)
 631 {
 632         struct inode *inode = filp->f_mapping->host;
 633         struct super_block * sb;
 634         int ret, err;
 635
 636         /* sync the inode to buffers */
 637         ret = write_inode_now(inode, 0);
 638
 639         /* sync the superblock to buffers */
 640         sb = inode->i_sb;
 641         if (sb->s_dirt) {
 642                 lock_super(sb);
 643                 sb->s_dirt = 0;
 644                 if (!(sb->s_flags & MS_RDONLY))
 645                         hfs_mdb_commit(sb);
 646                 unlock_super(sb);
 647         }
 648         /* .. finally sync the buffers to disk */
 649         err = sync_blockdev(sb->s_bdev);
 650         if (!ret)
 651                 ret = err;
 652         return ret;
 653 }
 654
 655 static const struct file_operations hfs_file_operations = {
 656         .llseek         = generic_file_llseek,
 657         .read           = do_sync_read,
 658         .aio_read       = generic_file_aio_read,
 659         .write          = do_sync_write,
 660         .aio_write      = generic_file_aio_write,
 661         .mmap           = generic_file_mmap,
 662         .splice_read    = generic_file_splice_read,
 663         .fsync          = hfs_file_fsync,
 664         .open           = hfs_file_open,
 665         .release        = hfs_file_release,
 666 };
 667
 668 static const struct inode_operations hfs_file_inode_operations = {
 669         .lookup         = hfs_file_lookup,
 670         .truncate       = hfs_file_truncate,
 671         .setattr        = hfs_inode_setattr,
 672         .setxattr       = hfs_setxattr,
 673         .getxattr       = hfs_getxattr,
 674         .listxattr      = hfs_listxattr,
 675 };