linux/fs/hfs/inode.c
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   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#include <linux/cred.h>
  18#include <linux/uio.h>
  19#include <linux/xattr.h>
  20
  21#include "hfs_fs.h"
  22#include "btree.h"
  23
  24static const struct file_operations hfs_file_operations;
  25static const struct inode_operations hfs_file_inode_operations;
  26
  27/*================ Variable-like macros ================*/
  28
  29#define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  30
  31static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  32{
  33        return block_write_full_page(page, hfs_get_block, wbc);
  34}
  35
  36static int hfs_readpage(struct file *file, struct page *page)
  37{
  38        return block_read_full_page(page, hfs_get_block);
  39}
  40
  41static void hfs_write_failed(struct address_space *mapping, loff_t to)
  42{
  43        struct inode *inode = mapping->host;
  44
  45        if (to > inode->i_size) {
  46                truncate_pagecache(inode, inode->i_size);
  47                hfs_file_truncate(inode);
  48        }
  49}
  50
  51static int hfs_write_begin(struct file *file, struct address_space *mapping,
  52                        loff_t pos, unsigned len, unsigned flags,
  53                        struct page **pagep, void **fsdata)
  54{
  55        int ret;
  56
  57        *pagep = NULL;
  58        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
  59                                hfs_get_block,
  60                                &HFS_I(mapping->host)->phys_size);
  61        if (unlikely(ret))
  62                hfs_write_failed(mapping, pos + len);
  63
  64        return ret;
  65}
  66
  67static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  68{
  69        return generic_block_bmap(mapping, block, hfs_get_block);
  70}
  71
  72static int hfs_releasepage(struct page *page, gfp_t mask)
  73{
  74        struct inode *inode = page->mapping->host;
  75        struct super_block *sb = inode->i_sb;
  76        struct hfs_btree *tree;
  77        struct hfs_bnode *node;
  78        u32 nidx;
  79        int i, res = 1;
  80
  81        switch (inode->i_ino) {
  82        case HFS_EXT_CNID:
  83                tree = HFS_SB(sb)->ext_tree;
  84                break;
  85        case HFS_CAT_CNID:
  86                tree = HFS_SB(sb)->cat_tree;
  87                break;
  88        default:
  89                BUG();
  90                return 0;
  91        }
  92
  93        if (!tree)
  94                return 0;
  95
  96        if (tree->node_size >= PAGE_SIZE) {
  97                nidx = page->index >> (tree->node_size_shift - PAGE_SHIFT);
  98                spin_lock(&tree->hash_lock);
  99                node = hfs_bnode_findhash(tree, nidx);
 100                if (!node)
 101                        ;
 102                else if (atomic_read(&node->refcnt))
 103                        res = 0;
 104                if (res && node) {
 105                        hfs_bnode_unhash(node);
 106                        hfs_bnode_free(node);
 107                }
 108                spin_unlock(&tree->hash_lock);
 109        } else {
 110                nidx = page->index << (PAGE_SHIFT - tree->node_size_shift);
 111                i = 1 << (PAGE_SHIFT - tree->node_size_shift);
 112                spin_lock(&tree->hash_lock);
 113                do {
 114                        node = hfs_bnode_findhash(tree, nidx++);
 115                        if (!node)
 116                                continue;
 117                        if (atomic_read(&node->refcnt)) {
 118                                res = 0;
 119                                break;
 120                        }
 121                        hfs_bnode_unhash(node);
 122                        hfs_bnode_free(node);
 123                } while (--i && nidx < tree->node_count);
 124                spin_unlock(&tree->hash_lock);
 125        }
 126        return res ? try_to_free_buffers(page) : 0;
 127}
 128
 129static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 130{
 131        struct file *file = iocb->ki_filp;
 132        struct address_space *mapping = file->f_mapping;
 133        struct inode *inode = mapping->host;
 134        size_t count = iov_iter_count(iter);
 135        ssize_t ret;
 136
 137        ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
 138
 139        /*
 140         * In case of error extending write may have instantiated a few
 141         * blocks outside i_size. Trim these off again.
 142         */
 143        if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 144                loff_t isize = i_size_read(inode);
 145                loff_t end = iocb->ki_pos + count;
 146
 147                if (end > isize)
 148                        hfs_write_failed(mapping, end);
 149        }
 150
 151        return ret;
 152}
 153
 154static int hfs_writepages(struct address_space *mapping,
 155                          struct writeback_control *wbc)
 156{
 157        return mpage_writepages(mapping, wbc, hfs_get_block);
 158}
 159
 160const struct address_space_operations hfs_btree_aops = {
 161        .readpage       = hfs_readpage,
 162        .writepage      = hfs_writepage,
 163        .write_begin    = hfs_write_begin,
 164        .write_end      = generic_write_end,
 165        .bmap           = hfs_bmap,
 166        .releasepage    = hfs_releasepage,
 167};
 168
 169const struct address_space_operations hfs_aops = {
 170        .readpage       = hfs_readpage,
 171        .writepage      = hfs_writepage,
 172        .write_begin    = hfs_write_begin,
 173        .write_end      = generic_write_end,
 174        .bmap           = hfs_bmap,
 175        .direct_IO      = hfs_direct_IO,
 176        .writepages     = hfs_writepages,
 177};
 178
 179/*
 180 * hfs_new_inode
 181 */
 182struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
 183{
 184        struct super_block *sb = dir->i_sb;
 185        struct inode *inode = new_inode(sb);
 186        if (!inode)
 187                return NULL;
 188
 189        mutex_init(&HFS_I(inode)->extents_lock);
 190        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 191        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 192        hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 193        inode->i_ino = HFS_SB(sb)->next_id++;
 194        inode->i_mode = mode;
 195        inode->i_uid = current_fsuid();
 196        inode->i_gid = current_fsgid();
 197        set_nlink(inode, 1);
 198        inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 199        HFS_I(inode)->flags = 0;
 200        HFS_I(inode)->rsrc_inode = NULL;
 201        HFS_I(inode)->fs_blocks = 0;
 202        if (S_ISDIR(mode)) {
 203                inode->i_size = 2;
 204                HFS_SB(sb)->folder_count++;
 205                if (dir->i_ino == HFS_ROOT_CNID)
 206                        HFS_SB(sb)->root_dirs++;
 207                inode->i_op = &hfs_dir_inode_operations;
 208                inode->i_fop = &hfs_dir_operations;
 209                inode->i_mode |= S_IRWXUGO;
 210                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 211        } else if (S_ISREG(mode)) {
 212                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 213                HFS_SB(sb)->file_count++;
 214                if (dir->i_ino == HFS_ROOT_CNID)
 215                        HFS_SB(sb)->root_files++;
 216                inode->i_op = &hfs_file_inode_operations;
 217                inode->i_fop = &hfs_file_operations;
 218                inode->i_mapping->a_ops = &hfs_aops;
 219                inode->i_mode |= S_IRUGO|S_IXUGO;
 220                if (mode & S_IWUSR)
 221                        inode->i_mode |= S_IWUGO;
 222                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 223                HFS_I(inode)->phys_size = 0;
 224                HFS_I(inode)->alloc_blocks = 0;
 225                HFS_I(inode)->first_blocks = 0;
 226                HFS_I(inode)->cached_start = 0;
 227                HFS_I(inode)->cached_blocks = 0;
 228                memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 229                memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 230        }
 231        insert_inode_hash(inode);
 232        mark_inode_dirty(inode);
 233        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 234        hfs_mark_mdb_dirty(sb);
 235
 236        return inode;
 237}
 238
 239void hfs_delete_inode(struct inode *inode)
 240{
 241        struct super_block *sb = inode->i_sb;
 242
 243        hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
 244        if (S_ISDIR(inode->i_mode)) {
 245                HFS_SB(sb)->folder_count--;
 246                if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 247                        HFS_SB(sb)->root_dirs--;
 248                set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 249                hfs_mark_mdb_dirty(sb);
 250                return;
 251        }
 252        HFS_SB(sb)->file_count--;
 253        if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 254                HFS_SB(sb)->root_files--;
 255        if (S_ISREG(inode->i_mode)) {
 256                if (!inode->i_nlink) {
 257                        inode->i_size = 0;
 258                        hfs_file_truncate(inode);
 259                }
 260        }
 261        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 262        hfs_mark_mdb_dirty(sb);
 263}
 264
 265void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 266                         __be32 __log_size, __be32 phys_size, u32 clump_size)
 267{
 268        struct super_block *sb = inode->i_sb;
 269        u32 log_size = be32_to_cpu(__log_size);
 270        u16 count;
 271        int i;
 272
 273        memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 274        for (count = 0, i = 0; i < 3; i++)
 275                count += be16_to_cpu(ext[i].count);
 276        HFS_I(inode)->first_blocks = count;
 277
 278        inode->i_size = HFS_I(inode)->phys_size = log_size;
 279        HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 280        inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 281        HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 282                                     HFS_SB(sb)->alloc_blksz;
 283        HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 284        if (!HFS_I(inode)->clump_blocks)
 285                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 286}
 287
 288struct hfs_iget_data {
 289        struct hfs_cat_key *key;
 290        hfs_cat_rec *rec;
 291};
 292
 293static int hfs_test_inode(struct inode *inode, void *data)
 294{
 295        struct hfs_iget_data *idata = data;
 296        hfs_cat_rec *rec;
 297
 298        rec = idata->rec;
 299        switch (rec->type) {
 300        case HFS_CDR_DIR:
 301                return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 302        case HFS_CDR_FIL:
 303                return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 304        default:
 305                BUG();
 306                return 1;
 307        }
 308}
 309
 310/*
 311 * hfs_read_inode
 312 */
 313static int hfs_read_inode(struct inode *inode, void *data)
 314{
 315        struct hfs_iget_data *idata = data;
 316        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 317        hfs_cat_rec *rec;
 318
 319        HFS_I(inode)->flags = 0;
 320        HFS_I(inode)->rsrc_inode = NULL;
 321        mutex_init(&HFS_I(inode)->extents_lock);
 322        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 323        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 324
 325        /* Initialize the inode */
 326        inode->i_uid = hsb->s_uid;
 327        inode->i_gid = hsb->s_gid;
 328        set_nlink(inode, 1);
 329
 330        if (idata->key)
 331                HFS_I(inode)->cat_key = *idata->key;
 332        else
 333                HFS_I(inode)->flags |= HFS_FLG_RSRC;
 334        HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 335
 336        rec = idata->rec;
 337        switch (rec->type) {
 338        case HFS_CDR_FIL:
 339                if (!HFS_IS_RSRC(inode)) {
 340                        hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 341                                            rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 342                } else {
 343                        hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 344                                            rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 345                }
 346
 347                inode->i_ino = be32_to_cpu(rec->file.FlNum);
 348                inode->i_mode = S_IRUGO | S_IXUGO;
 349                if (!(rec->file.Flags & HFS_FIL_LOCK))
 350                        inode->i_mode |= S_IWUGO;
 351                inode->i_mode &= ~hsb->s_file_umask;
 352                inode->i_mode |= S_IFREG;
 353                inode->i_ctime = inode->i_atime = inode->i_mtime =
 354                                hfs_m_to_utime(rec->file.MdDat);
 355                inode->i_op = &hfs_file_inode_operations;
 356                inode->i_fop = &hfs_file_operations;
 357                inode->i_mapping->a_ops = &hfs_aops;
 358                break;
 359        case HFS_CDR_DIR:
 360                inode->i_ino = be32_to_cpu(rec->dir.DirID);
 361                inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 362                HFS_I(inode)->fs_blocks = 0;
 363                inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 364                inode->i_ctime = inode->i_atime = inode->i_mtime =
 365                                hfs_m_to_utime(rec->dir.MdDat);
 366                inode->i_op = &hfs_dir_inode_operations;
 367                inode->i_fop = &hfs_dir_operations;
 368                break;
 369        default:
 370                make_bad_inode(inode);
 371        }
 372        return 0;
 373}
 374
 375/*
 376 * __hfs_iget()
 377 *
 378 * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 379 * the catalog B-tree and the 'type' of the desired file return the
 380 * inode for that file/directory or NULL.  Note that 'type' indicates
 381 * whether we want the actual file or directory, or the corresponding
 382 * metadata (AppleDouble header file or CAP metadata file).
 383 */
 384struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 385{
 386        struct hfs_iget_data data = { key, rec };
 387        struct inode *inode;
 388        u32 cnid;
 389
 390        switch (rec->type) {
 391        case HFS_CDR_DIR:
 392                cnid = be32_to_cpu(rec->dir.DirID);
 393                break;
 394        case HFS_CDR_FIL:
 395                cnid = be32_to_cpu(rec->file.FlNum);
 396                break;
 397        default:
 398                return NULL;
 399        }
 400        inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 401        if (inode && (inode->i_state & I_NEW))
 402                unlock_new_inode(inode);
 403        return inode;
 404}
 405
 406void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 407                          __be32 *log_size, __be32 *phys_size)
 408{
 409        memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 410
 411        if (log_size)
 412                *log_size = cpu_to_be32(inode->i_size);
 413        if (phys_size)
 414                *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 415                                         HFS_SB(inode->i_sb)->alloc_blksz);
 416}
 417
 418int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 419{
 420        struct inode *main_inode = inode;
 421        struct hfs_find_data fd;
 422        hfs_cat_rec rec;
 423        int res;
 424
 425        hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 426        res = hfs_ext_write_extent(inode);
 427        if (res)
 428                return res;
 429
 430        if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 431                switch (inode->i_ino) {
 432                case HFS_ROOT_CNID:
 433                        break;
 434                case HFS_EXT_CNID:
 435                        hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 436                        return 0;
 437                case HFS_CAT_CNID:
 438                        hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 439                        return 0;
 440                default:
 441                        BUG();
 442                        return -EIO;
 443                }
 444        }
 445
 446        if (HFS_IS_RSRC(inode))
 447                main_inode = HFS_I(inode)->rsrc_inode;
 448
 449        if (!main_inode->i_nlink)
 450                return 0;
 451
 452        if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 453                /* panic? */
 454                return -EIO;
 455
 456        fd.search_key->cat = HFS_I(main_inode)->cat_key;
 457        if (hfs_brec_find(&fd))
 458                /* panic? */
 459                goto out;
 460
 461        if (S_ISDIR(main_inode->i_mode)) {
 462                if (fd.entrylength < sizeof(struct hfs_cat_dir))
 463                        /* panic? */;
 464                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 465                           sizeof(struct hfs_cat_dir));
 466                if (rec.type != HFS_CDR_DIR ||
 467                    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 468                }
 469
 470                rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 471                rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 472
 473                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 474                            sizeof(struct hfs_cat_dir));
 475        } else if (HFS_IS_RSRC(inode)) {
 476                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 477                               sizeof(struct hfs_cat_file));
 478                hfs_inode_write_fork(inode, rec.file.RExtRec,
 479                                     &rec.file.RLgLen, &rec.file.RPyLen);
 480                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 481                                sizeof(struct hfs_cat_file));
 482        } else {
 483                if (fd.entrylength < sizeof(struct hfs_cat_file))
 484                        /* panic? */;
 485                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 486                           sizeof(struct hfs_cat_file));
 487                if (rec.type != HFS_CDR_FIL ||
 488                    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 489                }
 490
 491                if (inode->i_mode & S_IWUSR)
 492                        rec.file.Flags &= ~HFS_FIL_LOCK;
 493                else
 494                        rec.file.Flags |= HFS_FIL_LOCK;
 495                hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 496                rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 497
 498                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 499                            sizeof(struct hfs_cat_file));
 500        }
 501out:
 502        hfs_find_exit(&fd);
 503        return 0;
 504}
 505
 506static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 507                                      unsigned int flags)
 508{
 509        struct inode *inode = NULL;
 510        hfs_cat_rec rec;
 511        struct hfs_find_data fd;
 512        int res;
 513
 514        if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 515                goto out;
 516
 517        inode = HFS_I(dir)->rsrc_inode;
 518        if (inode)
 519                goto out;
 520
 521        inode = new_inode(dir->i_sb);
 522        if (!inode)
 523                return ERR_PTR(-ENOMEM);
 524
 525        res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 526        if (res) {
 527                iput(inode);
 528                return ERR_PTR(res);
 529        }
 530        fd.search_key->cat = HFS_I(dir)->cat_key;
 531        res = hfs_brec_read(&fd, &rec, sizeof(rec));
 532        if (!res) {
 533                struct hfs_iget_data idata = { NULL, &rec };
 534                hfs_read_inode(inode, &idata);
 535        }
 536        hfs_find_exit(&fd);
 537        if (res) {
 538                iput(inode);
 539                return ERR_PTR(res);
 540        }
 541        HFS_I(inode)->rsrc_inode = dir;
 542        HFS_I(dir)->rsrc_inode = inode;
 543        igrab(dir);
 544        hlist_add_fake(&inode->i_hash);
 545        mark_inode_dirty(inode);
 546out:
 547        d_add(dentry, inode);
 548        return NULL;
 549}
 550
 551void hfs_evict_inode(struct inode *inode)
 552{
 553        truncate_inode_pages_final(&inode->i_data);
 554        clear_inode(inode);
 555        if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 556                HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 557                iput(HFS_I(inode)->rsrc_inode);
 558        }
 559}
 560
 561static int hfs_file_open(struct inode *inode, struct file *file)
 562{
 563        if (HFS_IS_RSRC(inode))
 564                inode = HFS_I(inode)->rsrc_inode;
 565        atomic_inc(&HFS_I(inode)->opencnt);
 566        return 0;
 567}
 568
 569static int hfs_file_release(struct inode *inode, struct file *file)
 570{
 571        //struct super_block *sb = inode->i_sb;
 572
 573        if (HFS_IS_RSRC(inode))
 574                inode = HFS_I(inode)->rsrc_inode;
 575        if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 576                inode_lock(inode);
 577                hfs_file_truncate(inode);
 578                //if (inode->i_flags & S_DEAD) {
 579                //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 580                //      hfs_delete_inode(inode);
 581                //}
 582                inode_unlock(inode);
 583        }
 584        return 0;
 585}
 586
 587/*
 588 * hfs_notify_change()
 589 *
 590 * Based very closely on fs/msdos/inode.c by Werner Almesberger
 591 *
 592 * This is the notify_change() field in the super_operations structure
 593 * for HFS file systems.  The purpose is to take that changes made to
 594 * an inode and apply then in a filesystem-dependent manner.  In this
 595 * case the process has a few of tasks to do:
 596 *  1) prevent changes to the i_uid and i_gid fields.
 597 *  2) map file permissions to the closest allowable permissions
 598 *  3) Since multiple Linux files can share the same on-disk inode under
 599 *     HFS (for instance the data and resource forks of a file) a change
 600 *     to permissions must be applied to all other in-core inodes which
 601 *     correspond to the same HFS file.
 602 */
 603
 604int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
 605{
 606        struct inode *inode = d_inode(dentry);
 607        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 608        int error;
 609
 610        error = setattr_prepare(dentry, attr); /* basic permission checks */
 611        if (error)
 612                return error;
 613
 614        /* no uig/gid changes and limit which mode bits can be set */
 615        if (((attr->ia_valid & ATTR_UID) &&
 616             (!uid_eq(attr->ia_uid, hsb->s_uid))) ||
 617            ((attr->ia_valid & ATTR_GID) &&
 618             (!gid_eq(attr->ia_gid, hsb->s_gid))) ||
 619            ((attr->ia_valid & ATTR_MODE) &&
 620             ((S_ISDIR(inode->i_mode) &&
 621               (attr->ia_mode != inode->i_mode)) ||
 622              (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 623                return hsb->s_quiet ? 0 : error;
 624        }
 625
 626        if (attr->ia_valid & ATTR_MODE) {
 627                /* Only the 'w' bits can ever change and only all together. */
 628                if (attr->ia_mode & S_IWUSR)
 629                        attr->ia_mode = inode->i_mode | S_IWUGO;
 630                else
 631                        attr->ia_mode = inode->i_mode & ~S_IWUGO;
 632                attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 633        }
 634
 635        if ((attr->ia_valid & ATTR_SIZE) &&
 636            attr->ia_size != i_size_read(inode)) {
 637                inode_dio_wait(inode);
 638
 639                error = inode_newsize_ok(inode, attr->ia_size);
 640                if (error)
 641                        return error;
 642
 643                truncate_setsize(inode, attr->ia_size);
 644                hfs_file_truncate(inode);
 645        }
 646
 647        setattr_copy(inode, attr);
 648        mark_inode_dirty(inode);
 649        return 0;
 650}
 651
 652static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
 653                          int datasync)
 654{
 655        struct inode *inode = filp->f_mapping->host;
 656        struct super_block * sb;
 657        int ret, err;
 658
 659        ret = file_write_and_wait_range(filp, start, end);
 660        if (ret)
 661                return ret;
 662        inode_lock(inode);
 663
 664        /* sync the inode to buffers */
 665        ret = write_inode_now(inode, 0);
 666
 667        /* sync the superblock to buffers */
 668        sb = inode->i_sb;
 669        flush_delayed_work(&HFS_SB(sb)->mdb_work);
 670        /* .. finally sync the buffers to disk */
 671        err = sync_blockdev(sb->s_bdev);
 672        if (!ret)
 673                ret = err;
 674        inode_unlock(inode);
 675        return ret;
 676}
 677
 678static const struct file_operations hfs_file_operations = {
 679        .llseek         = generic_file_llseek,
 680        .read_iter      = generic_file_read_iter,
 681        .write_iter     = generic_file_write_iter,
 682        .mmap           = generic_file_mmap,
 683        .splice_read    = generic_file_splice_read,
 684        .fsync          = hfs_file_fsync,
 685        .open           = hfs_file_open,
 686        .release        = hfs_file_release,
 687};
 688
 689static const struct inode_operations hfs_file_inode_operations = {
 690        .lookup         = hfs_file_lookup,
 691        .setattr        = hfs_inode_setattr,
 692        .listxattr      = generic_listxattr,
 693};
 694