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#include <linux/blkdev.h>
  21
  22#include "hfs_fs.h"
  23#include "btree.h"
  24
  25static const struct file_operations hfs_file_operations;
  26static const struct inode_operations hfs_file_inode_operations;
  27
  28/*================ Variable-like macros ================*/
  29
  30#define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  31
  32static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  33{
  34        return block_write_full_page(page, hfs_get_block, wbc);
  35}
  36
  37static int hfs_readpage(struct file *file, struct page *page)
  38{
  39        return block_read_full_page(page, hfs_get_block);
  40}
  41
  42static void hfs_write_failed(struct address_space *mapping, loff_t to)
  43{
  44        struct inode *inode = mapping->host;
  45
  46        if (to > inode->i_size) {
  47                truncate_pagecache(inode, inode->i_size);
  48                hfs_file_truncate(inode);
  49        }
  50}
  51
  52static int hfs_write_begin(struct file *file, struct address_space *mapping,
  53                        loff_t pos, unsigned len, unsigned flags,
  54                        struct page **pagep, void **fsdata)
  55{
  56        int ret;
  57
  58        *pagep = NULL;
  59        ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
  60                                hfs_get_block,
  61                                &HFS_I(mapping->host)->phys_size);
  62        if (unlikely(ret))
  63                hfs_write_failed(mapping, pos + len);
  64
  65        return ret;
  66}
  67
  68static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  69{
  70        return generic_block_bmap(mapping, block, hfs_get_block);
  71}
  72
  73static int hfs_releasepage(struct page *page, gfp_t mask)
  74{
  75        struct inode *inode = page->mapping->host;
  76        struct super_block *sb = inode->i_sb;
  77        struct hfs_btree *tree;
  78        struct hfs_bnode *node;
  79        u32 nidx;
  80        int i, res = 1;
  81
  82        switch (inode->i_ino) {
  83        case HFS_EXT_CNID:
  84                tree = HFS_SB(sb)->ext_tree;
  85                break;
  86        case HFS_CAT_CNID:
  87                tree = HFS_SB(sb)->cat_tree;
  88                break;
  89        default:
  90                BUG();
  91                return 0;
  92        }
  93
  94        if (!tree)
  95                return 0;
  96
  97        if (tree->node_size >= PAGE_SIZE) {
  98                nidx = page->index >> (tree->node_size_shift - PAGE_SHIFT);
  99                spin_lock(&tree->hash_lock);
 100                node = hfs_bnode_findhash(tree, nidx);
 101                if (!node)
 102                        ;
 103                else if (atomic_read(&node->refcnt))
 104                        res = 0;
 105                if (res && node) {
 106                        hfs_bnode_unhash(node);
 107                        hfs_bnode_free(node);
 108                }
 109                spin_unlock(&tree->hash_lock);
 110        } else {
 111                nidx = page->index << (PAGE_SHIFT - tree->node_size_shift);
 112                i = 1 << (PAGE_SHIFT - tree->node_size_shift);
 113                spin_lock(&tree->hash_lock);
 114                do {
 115                        node = hfs_bnode_findhash(tree, nidx++);
 116                        if (!node)
 117                                continue;
 118                        if (atomic_read(&node->refcnt)) {
 119                                res = 0;
 120                                break;
 121                        }
 122                        hfs_bnode_unhash(node);
 123                        hfs_bnode_free(node);
 124                } while (--i && nidx < tree->node_count);
 125                spin_unlock(&tree->hash_lock);
 126        }
 127        return res ? try_to_free_buffers(page) : 0;
 128}
 129
 130static ssize_t hfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 131{
 132        struct file *file = iocb->ki_filp;
 133        struct address_space *mapping = file->f_mapping;
 134        struct inode *inode = mapping->host;
 135        size_t count = iov_iter_count(iter);
 136        ssize_t ret;
 137
 138        ret = blockdev_direct_IO(iocb, inode, iter, hfs_get_block);
 139
 140        /*
 141         * In case of error extending write may have instantiated a few
 142         * blocks outside i_size. Trim these off again.
 143         */
 144        if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
 145                loff_t isize = i_size_read(inode);
 146                loff_t end = iocb->ki_pos + count;
 147
 148                if (end > isize)
 149                        hfs_write_failed(mapping, end);
 150        }
 151
 152        return ret;
 153}
 154
 155static int hfs_writepages(struct address_space *mapping,
 156                          struct writeback_control *wbc)
 157{
 158        return mpage_writepages(mapping, wbc, hfs_get_block);
 159}
 160
 161const struct address_space_operations hfs_btree_aops = {
 162        .readpage       = hfs_readpage,
 163        .writepage      = hfs_writepage,
 164        .write_begin    = hfs_write_begin,
 165        .write_end      = generic_write_end,
 166        .bmap           = hfs_bmap,
 167        .releasepage    = hfs_releasepage,
 168};
 169
 170const struct address_space_operations hfs_aops = {
 171        .readpage       = hfs_readpage,
 172        .writepage      = hfs_writepage,
 173        .write_begin    = hfs_write_begin,
 174        .write_end      = generic_write_end,
 175        .bmap           = hfs_bmap,
 176        .direct_IO      = hfs_direct_IO,
 177        .writepages     = hfs_writepages,
 178};
 179
 180/*
 181 * hfs_new_inode
 182 */
 183struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
 184{
 185        struct super_block *sb = dir->i_sb;
 186        struct inode *inode = new_inode(sb);
 187        if (!inode)
 188                return NULL;
 189
 190        mutex_init(&HFS_I(inode)->extents_lock);
 191        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 192        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 193        hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 194        inode->i_ino = HFS_SB(sb)->next_id++;
 195        inode->i_mode = mode;
 196        inode->i_uid = current_fsuid();
 197        inode->i_gid = current_fsgid();
 198        set_nlink(inode, 1);
 199        inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 200        HFS_I(inode)->flags = 0;
 201        HFS_I(inode)->rsrc_inode = NULL;
 202        HFS_I(inode)->fs_blocks = 0;
 203        if (S_ISDIR(mode)) {
 204                inode->i_size = 2;
 205                HFS_SB(sb)->folder_count++;
 206                if (dir->i_ino == HFS_ROOT_CNID)
 207                        HFS_SB(sb)->root_dirs++;
 208                inode->i_op = &hfs_dir_inode_operations;
 209                inode->i_fop = &hfs_dir_operations;
 210                inode->i_mode |= S_IRWXUGO;
 211                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 212        } else if (S_ISREG(mode)) {
 213                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 214                HFS_SB(sb)->file_count++;
 215                if (dir->i_ino == HFS_ROOT_CNID)
 216                        HFS_SB(sb)->root_files++;
 217                inode->i_op = &hfs_file_inode_operations;
 218                inode->i_fop = &hfs_file_operations;
 219                inode->i_mapping->a_ops = &hfs_aops;
 220                inode->i_mode |= S_IRUGO|S_IXUGO;
 221                if (mode & S_IWUSR)
 222                        inode->i_mode |= S_IWUGO;
 223                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 224                HFS_I(inode)->phys_size = 0;
 225                HFS_I(inode)->alloc_blocks = 0;
 226                HFS_I(inode)->first_blocks = 0;
 227                HFS_I(inode)->cached_start = 0;
 228                HFS_I(inode)->cached_blocks = 0;
 229                memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 230                memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 231        }
 232        insert_inode_hash(inode);
 233        mark_inode_dirty(inode);
 234        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 235        hfs_mark_mdb_dirty(sb);
 236
 237        return inode;
 238}
 239
 240void hfs_delete_inode(struct inode *inode)
 241{
 242        struct super_block *sb = inode->i_sb;
 243
 244        hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
 245        if (S_ISDIR(inode->i_mode)) {
 246                HFS_SB(sb)->folder_count--;
 247                if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 248                        HFS_SB(sb)->root_dirs--;
 249                set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 250                hfs_mark_mdb_dirty(sb);
 251                return;
 252        }
 253        HFS_SB(sb)->file_count--;
 254        if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 255                HFS_SB(sb)->root_files--;
 256        if (S_ISREG(inode->i_mode)) {
 257                if (!inode->i_nlink) {
 258                        inode->i_size = 0;
 259                        hfs_file_truncate(inode);
 260                }
 261        }
 262        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 263        hfs_mark_mdb_dirty(sb);
 264}
 265
 266void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 267                         __be32 __log_size, __be32 phys_size, u32 clump_size)
 268{
 269        struct super_block *sb = inode->i_sb;
 270        u32 log_size = be32_to_cpu(__log_size);
 271        u16 count;
 272        int i;
 273
 274        memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 275        for (count = 0, i = 0; i < 3; i++)
 276                count += be16_to_cpu(ext[i].count);
 277        HFS_I(inode)->first_blocks = count;
 278
 279        inode->i_size = HFS_I(inode)->phys_size = log_size;
 280        HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 281        inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 282        HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 283                                     HFS_SB(sb)->alloc_blksz;
 284        HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 285        if (!HFS_I(inode)->clump_blocks)
 286                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 287}
 288
 289struct hfs_iget_data {
 290        struct hfs_cat_key *key;
 291        hfs_cat_rec *rec;
 292};
 293
 294static int hfs_test_inode(struct inode *inode, void *data)
 295{
 296        struct hfs_iget_data *idata = data;
 297        hfs_cat_rec *rec;
 298
 299        rec = idata->rec;
 300        switch (rec->type) {
 301        case HFS_CDR_DIR:
 302                return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 303        case HFS_CDR_FIL:
 304                return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 305        default:
 306                BUG();
 307                return 1;
 308        }
 309}
 310
 311/*
 312 * hfs_read_inode
 313 */
 314static int hfs_read_inode(struct inode *inode, void *data)
 315{
 316        struct hfs_iget_data *idata = data;
 317        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 318        hfs_cat_rec *rec;
 319
 320        HFS_I(inode)->flags = 0;
 321        HFS_I(inode)->rsrc_inode = NULL;
 322        mutex_init(&HFS_I(inode)->extents_lock);
 323        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 324        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 325
 326        /* Initialize the inode */
 327        inode->i_uid = hsb->s_uid;
 328        inode->i_gid = hsb->s_gid;
 329        set_nlink(inode, 1);
 330
 331        if (idata->key)
 332                HFS_I(inode)->cat_key = *idata->key;
 333        else
 334                HFS_I(inode)->flags |= HFS_FLG_RSRC;
 335        HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 336
 337        rec = idata->rec;
 338        switch (rec->type) {
 339        case HFS_CDR_FIL:
 340                if (!HFS_IS_RSRC(inode)) {
 341                        hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 342                                            rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 343                } else {
 344                        hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 345                                            rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 346                }
 347
 348                inode->i_ino = be32_to_cpu(rec->file.FlNum);
 349                inode->i_mode = S_IRUGO | S_IXUGO;
 350                if (!(rec->file.Flags & HFS_FIL_LOCK))
 351                        inode->i_mode |= S_IWUGO;
 352                inode->i_mode &= ~hsb->s_file_umask;
 353                inode->i_mode |= S_IFREG;
 354                inode->i_ctime = inode->i_atime = inode->i_mtime =
 355                                hfs_m_to_utime(rec->file.MdDat);
 356                inode->i_op = &hfs_file_inode_operations;
 357                inode->i_fop = &hfs_file_operations;
 358                inode->i_mapping->a_ops = &hfs_aops;
 359                break;
 360        case HFS_CDR_DIR:
 361                inode->i_ino = be32_to_cpu(rec->dir.DirID);
 362                inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 363                HFS_I(inode)->fs_blocks = 0;
 364                inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 365                inode->i_ctime = inode->i_atime = inode->i_mtime =
 366                                hfs_m_to_utime(rec->dir.MdDat);
 367                inode->i_op = &hfs_dir_inode_operations;
 368                inode->i_fop = &hfs_dir_operations;
 369                break;
 370        default:
 371                make_bad_inode(inode);
 372        }
 373        return 0;
 374}
 375
 376/*
 377 * __hfs_iget()
 378 *
 379 * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 380 * the catalog B-tree and the 'type' of the desired file return the
 381 * inode for that file/directory or NULL.  Note that 'type' indicates
 382 * whether we want the actual file or directory, or the corresponding
 383 * metadata (AppleDouble header file or CAP metadata file).
 384 */
 385struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 386{
 387        struct hfs_iget_data data = { key, rec };
 388        struct inode *inode;
 389        u32 cnid;
 390
 391        switch (rec->type) {
 392        case HFS_CDR_DIR:
 393                cnid = be32_to_cpu(rec->dir.DirID);
 394                break;
 395        case HFS_CDR_FIL:
 396                cnid = be32_to_cpu(rec->file.FlNum);
 397                break;
 398        default:
 399                return NULL;
 400        }
 401        inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 402        if (inode && (inode->i_state & I_NEW))
 403                unlock_new_inode(inode);
 404        return inode;
 405}
 406
 407void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 408                          __be32 *log_size, __be32 *phys_size)
 409{
 410        memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 411
 412        if (log_size)
 413                *log_size = cpu_to_be32(inode->i_size);
 414        if (phys_size)
 415                *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 416                                         HFS_SB(inode->i_sb)->alloc_blksz);
 417}
 418
 419int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 420{
 421        struct inode *main_inode = inode;
 422        struct hfs_find_data fd;
 423        hfs_cat_rec rec;
 424        int res;
 425
 426        hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 427        res = hfs_ext_write_extent(inode);
 428        if (res)
 429                return res;
 430
 431        if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 432                switch (inode->i_ino) {
 433                case HFS_ROOT_CNID:
 434                        break;
 435                case HFS_EXT_CNID:
 436                        hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 437                        return 0;
 438                case HFS_CAT_CNID:
 439                        hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 440                        return 0;
 441                default:
 442                        BUG();
 443                        return -EIO;
 444                }
 445        }
 446
 447        if (HFS_IS_RSRC(inode))
 448                main_inode = HFS_I(inode)->rsrc_inode;
 449
 450        if (!main_inode->i_nlink)
 451                return 0;
 452
 453        if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 454                /* panic? */
 455                return -EIO;
 456
 457        fd.search_key->cat = HFS_I(main_inode)->cat_key;
 458        if (hfs_brec_find(&fd))
 459                /* panic? */
 460                goto out;
 461
 462        if (S_ISDIR(main_inode->i_mode)) {
 463                if (fd.entrylength < sizeof(struct hfs_cat_dir))
 464                        /* panic? */;
 465                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 466                           sizeof(struct hfs_cat_dir));
 467                if (rec.type != HFS_CDR_DIR ||
 468                    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 469                }
 470
 471                rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 472                rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 473
 474                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 475                            sizeof(struct hfs_cat_dir));
 476        } else if (HFS_IS_RSRC(inode)) {
 477                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 478                               sizeof(struct hfs_cat_file));
 479                hfs_inode_write_fork(inode, rec.file.RExtRec,
 480                                     &rec.file.RLgLen, &rec.file.RPyLen);
 481                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 482                                sizeof(struct hfs_cat_file));
 483        } else {
 484                if (fd.entrylength < sizeof(struct hfs_cat_file))
 485                        /* panic? */;
 486                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 487                           sizeof(struct hfs_cat_file));
 488                if (rec.type != HFS_CDR_FIL ||
 489                    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 490                }
 491
 492                if (inode->i_mode & S_IWUSR)
 493                        rec.file.Flags &= ~HFS_FIL_LOCK;
 494                else
 495                        rec.file.Flags |= HFS_FIL_LOCK;
 496                hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 497                rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 498
 499                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 500                            sizeof(struct hfs_cat_file));
 501        }
 502out:
 503        hfs_find_exit(&fd);
 504        return 0;
 505}
 506
 507static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 508                                      unsigned int flags)
 509{
 510        struct inode *inode = NULL;
 511        hfs_cat_rec rec;
 512        struct hfs_find_data fd;
 513        int res;
 514
 515        if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 516                goto out;
 517
 518        inode = HFS_I(dir)->rsrc_inode;
 519        if (inode)
 520                goto out;
 521
 522        inode = new_inode(dir->i_sb);
 523        if (!inode)
 524                return ERR_PTR(-ENOMEM);
 525
 526        res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 527        if (res) {
 528                iput(inode);
 529                return ERR_PTR(res);
 530        }
 531        fd.search_key->cat = HFS_I(dir)->cat_key;
 532        res = hfs_brec_read(&fd, &rec, sizeof(rec));
 533        if (!res) {
 534                struct hfs_iget_data idata = { NULL, &rec };
 535                hfs_read_inode(inode, &idata);
 536        }
 537        hfs_find_exit(&fd);
 538        if (res) {
 539                iput(inode);
 540                return ERR_PTR(res);
 541        }
 542        HFS_I(inode)->rsrc_inode = dir;
 543        HFS_I(dir)->rsrc_inode = inode;
 544        igrab(dir);
 545        inode_fake_hash(inode);
 546        mark_inode_dirty(inode);
 547        dont_mount(dentry);
 548out:
 549        return d_splice_alias(inode, dentry);
 550}
 551
 552void hfs_evict_inode(struct inode *inode)
 553{
 554        truncate_inode_pages_final(&inode->i_data);
 555        clear_inode(inode);
 556        if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 557                HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 558                iput(HFS_I(inode)->rsrc_inode);
 559        }
 560}
 561
 562static int hfs_file_open(struct inode *inode, struct file *file)
 563{
 564        if (HFS_IS_RSRC(inode))
 565                inode = HFS_I(inode)->rsrc_inode;
 566        atomic_inc(&HFS_I(inode)->opencnt);
 567        return 0;
 568}
 569
 570static int hfs_file_release(struct inode *inode, struct file *file)
 571{
 572        //struct super_block *sb = inode->i_sb;
 573
 574        if (HFS_IS_RSRC(inode))
 575                inode = HFS_I(inode)->rsrc_inode;
 576        if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 577                inode_lock(inode);
 578                hfs_file_truncate(inode);
 579                //if (inode->i_flags & S_DEAD) {
 580                //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 581                //      hfs_delete_inode(inode);
 582                //}
 583                inode_unlock(inode);
 584        }
 585        return 0;
 586}
 587
 588/*
 589 * hfs_notify_change()
 590 *
 591 * Based very closely on fs/msdos/inode.c by Werner Almesberger
 592 *
 593 * This is the notify_change() field in the super_operations structure
 594 * for HFS file systems.  The purpose is to take that changes made to
 595 * an inode and apply then in a filesystem-dependent manner.  In this
 596 * case the process has a few of tasks to do:
 597 *  1) prevent changes to the i_uid and i_gid fields.
 598 *  2) map file permissions to the closest allowable permissions
 599 *  3) Since multiple Linux files can share the same on-disk inode under
 600 *     HFS (for instance the data and resource forks of a file) a change
 601 *     to permissions must be applied to all other in-core inodes which
 602 *     correspond to the same HFS file.
 603 */
 604
 605int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
 606{
 607        struct inode *inode = d_inode(dentry);
 608        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 609        int error;
 610
 611        error = setattr_prepare(dentry, attr); /* basic permission checks */
 612        if (error)
 613                return error;
 614
 615        /* no uig/gid changes and limit which mode bits can be set */
 616        if (((attr->ia_valid & ATTR_UID) &&
 617             (!uid_eq(attr->ia_uid, hsb->s_uid))) ||
 618            ((attr->ia_valid & ATTR_GID) &&
 619             (!gid_eq(attr->ia_gid, hsb->s_gid))) ||
 620            ((attr->ia_valid & ATTR_MODE) &&
 621             ((S_ISDIR(inode->i_mode) &&
 622               (attr->ia_mode != inode->i_mode)) ||
 623              (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 624                return hsb->s_quiet ? 0 : error;
 625        }
 626
 627        if (attr->ia_valid & ATTR_MODE) {
 628                /* Only the 'w' bits can ever change and only all together. */
 629                if (attr->ia_mode & S_IWUSR)
 630                        attr->ia_mode = inode->i_mode | S_IWUGO;
 631                else
 632                        attr->ia_mode = inode->i_mode & ~S_IWUGO;
 633                attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 634        }
 635
 636        if ((attr->ia_valid & ATTR_SIZE) &&
 637            attr->ia_size != i_size_read(inode)) {
 638                inode_dio_wait(inode);
 639
 640                error = inode_newsize_ok(inode, attr->ia_size);
 641                if (error)
 642                        return error;
 643
 644                truncate_setsize(inode, attr->ia_size);
 645                hfs_file_truncate(inode);
 646                inode->i_atime = inode->i_mtime = inode->i_ctime =
 647                                                  current_time(inode);
 648        }
 649
 650        setattr_copy(inode, attr);
 651        mark_inode_dirty(inode);
 652        return 0;
 653}
 654
 655static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
 656                          int datasync)
 657{
 658        struct inode *inode = filp->f_mapping->host;
 659        struct super_block * sb;
 660        int ret, err;
 661
 662        ret = file_write_and_wait_range(filp, start, end);
 663        if (ret)
 664                return ret;
 665        inode_lock(inode);
 666
 667        /* sync the inode to buffers */
 668        ret = write_inode_now(inode, 0);
 669
 670        /* sync the superblock to buffers */
 671        sb = inode->i_sb;
 672        flush_delayed_work(&HFS_SB(sb)->mdb_work);
 673        /* .. finally sync the buffers to disk */
 674        err = sync_blockdev(sb->s_bdev);
 675        if (!ret)
 676                ret = err;
 677        inode_unlock(inode);
 678        return ret;
 679}
 680
 681static const struct file_operations hfs_file_operations = {
 682        .llseek         = generic_file_llseek,
 683        .read_iter      = generic_file_read_iter,
 684        .write_iter     = generic_file_write_iter,
 685        .mmap           = generic_file_mmap,
 686        .splice_read    = generic_file_splice_read,
 687        .fsync          = hfs_file_fsync,
 688        .open           = hfs_file_open,
 689        .release        = hfs_file_release,
 690};
 691
 692static const struct inode_operations hfs_file_inode_operations = {
 693        .lookup         = hfs_file_lookup,
 694        .setattr        = hfs_inode_setattr,
 695        .listxattr      = generic_listxattr,
 696};
 697