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        .set_page_dirty = __set_page_dirty_buffers,
 163        .readpage       = hfs_readpage,
 164        .writepage      = hfs_writepage,
 165        .write_begin    = hfs_write_begin,
 166        .write_end      = generic_write_end,
 167        .bmap           = hfs_bmap,
 168        .releasepage    = hfs_releasepage,
 169};
 170
 171const struct address_space_operations hfs_aops = {
 172        .set_page_dirty = __set_page_dirty_buffers,
 173        .readpage       = hfs_readpage,
 174        .writepage      = hfs_writepage,
 175        .write_begin    = hfs_write_begin,
 176        .write_end      = generic_write_end,
 177        .bmap           = hfs_bmap,
 178        .direct_IO      = hfs_direct_IO,
 179        .writepages     = hfs_writepages,
 180};
 181
 182/*
 183 * hfs_new_inode
 184 */
 185struct inode *hfs_new_inode(struct inode *dir, const struct qstr *name, umode_t mode)
 186{
 187        struct super_block *sb = dir->i_sb;
 188        struct inode *inode = new_inode(sb);
 189        if (!inode)
 190                return NULL;
 191
 192        mutex_init(&HFS_I(inode)->extents_lock);
 193        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 194        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 195        hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);
 196        inode->i_ino = HFS_SB(sb)->next_id++;
 197        inode->i_mode = mode;
 198        inode->i_uid = current_fsuid();
 199        inode->i_gid = current_fsgid();
 200        set_nlink(inode, 1);
 201        inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 202        HFS_I(inode)->flags = 0;
 203        HFS_I(inode)->rsrc_inode = NULL;
 204        HFS_I(inode)->fs_blocks = 0;
 205        if (S_ISDIR(mode)) {
 206                inode->i_size = 2;
 207                HFS_SB(sb)->folder_count++;
 208                if (dir->i_ino == HFS_ROOT_CNID)
 209                        HFS_SB(sb)->root_dirs++;
 210                inode->i_op = &hfs_dir_inode_operations;
 211                inode->i_fop = &hfs_dir_operations;
 212                inode->i_mode |= S_IRWXUGO;
 213                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
 214        } else if (S_ISREG(mode)) {
 215                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 216                HFS_SB(sb)->file_count++;
 217                if (dir->i_ino == HFS_ROOT_CNID)
 218                        HFS_SB(sb)->root_files++;
 219                inode->i_op = &hfs_file_inode_operations;
 220                inode->i_fop = &hfs_file_operations;
 221                inode->i_mapping->a_ops = &hfs_aops;
 222                inode->i_mode |= S_IRUGO|S_IXUGO;
 223                if (mode & S_IWUSR)
 224                        inode->i_mode |= S_IWUGO;
 225                inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
 226                HFS_I(inode)->phys_size = 0;
 227                HFS_I(inode)->alloc_blocks = 0;
 228                HFS_I(inode)->first_blocks = 0;
 229                HFS_I(inode)->cached_start = 0;
 230                HFS_I(inode)->cached_blocks = 0;
 231                memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
 232                memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
 233        }
 234        insert_inode_hash(inode);
 235        mark_inode_dirty(inode);
 236        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 237        hfs_mark_mdb_dirty(sb);
 238
 239        return inode;
 240}
 241
 242void hfs_delete_inode(struct inode *inode)
 243{
 244        struct super_block *sb = inode->i_sb;
 245
 246        hfs_dbg(INODE, "delete_inode: %lu\n", inode->i_ino);
 247        if (S_ISDIR(inode->i_mode)) {
 248                HFS_SB(sb)->folder_count--;
 249                if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 250                        HFS_SB(sb)->root_dirs--;
 251                set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 252                hfs_mark_mdb_dirty(sb);
 253                return;
 254        }
 255        HFS_SB(sb)->file_count--;
 256        if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
 257                HFS_SB(sb)->root_files--;
 258        if (S_ISREG(inode->i_mode)) {
 259                if (!inode->i_nlink) {
 260                        inode->i_size = 0;
 261                        hfs_file_truncate(inode);
 262                }
 263        }
 264        set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
 265        hfs_mark_mdb_dirty(sb);
 266}
 267
 268void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
 269                         __be32 __log_size, __be32 phys_size, u32 clump_size)
 270{
 271        struct super_block *sb = inode->i_sb;
 272        u32 log_size = be32_to_cpu(__log_size);
 273        u16 count;
 274        int i;
 275
 276        memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
 277        for (count = 0, i = 0; i < 3; i++)
 278                count += be16_to_cpu(ext[i].count);
 279        HFS_I(inode)->first_blocks = count;
 280
 281        inode->i_size = HFS_I(inode)->phys_size = log_size;
 282        HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
 283        inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
 284        HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
 285                                     HFS_SB(sb)->alloc_blksz;
 286        HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
 287        if (!HFS_I(inode)->clump_blocks)
 288                HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
 289}
 290
 291struct hfs_iget_data {
 292        struct hfs_cat_key *key;
 293        hfs_cat_rec *rec;
 294};
 295
 296static int hfs_test_inode(struct inode *inode, void *data)
 297{
 298        struct hfs_iget_data *idata = data;
 299        hfs_cat_rec *rec;
 300
 301        rec = idata->rec;
 302        switch (rec->type) {
 303        case HFS_CDR_DIR:
 304                return inode->i_ino == be32_to_cpu(rec->dir.DirID);
 305        case HFS_CDR_FIL:
 306                return inode->i_ino == be32_to_cpu(rec->file.FlNum);
 307        default:
 308                BUG();
 309                return 1;
 310        }
 311}
 312
 313/*
 314 * hfs_read_inode
 315 */
 316static int hfs_read_inode(struct inode *inode, void *data)
 317{
 318        struct hfs_iget_data *idata = data;
 319        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 320        hfs_cat_rec *rec;
 321
 322        HFS_I(inode)->flags = 0;
 323        HFS_I(inode)->rsrc_inode = NULL;
 324        mutex_init(&HFS_I(inode)->extents_lock);
 325        INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
 326        spin_lock_init(&HFS_I(inode)->open_dir_lock);
 327
 328        /* Initialize the inode */
 329        inode->i_uid = hsb->s_uid;
 330        inode->i_gid = hsb->s_gid;
 331        set_nlink(inode, 1);
 332
 333        if (idata->key)
 334                HFS_I(inode)->cat_key = *idata->key;
 335        else
 336                HFS_I(inode)->flags |= HFS_FLG_RSRC;
 337        HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
 338
 339        rec = idata->rec;
 340        switch (rec->type) {
 341        case HFS_CDR_FIL:
 342                if (!HFS_IS_RSRC(inode)) {
 343                        hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
 344                                            rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
 345                } else {
 346                        hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
 347                                            rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
 348                }
 349
 350                inode->i_ino = be32_to_cpu(rec->file.FlNum);
 351                inode->i_mode = S_IRUGO | S_IXUGO;
 352                if (!(rec->file.Flags & HFS_FIL_LOCK))
 353                        inode->i_mode |= S_IWUGO;
 354                inode->i_mode &= ~hsb->s_file_umask;
 355                inode->i_mode |= S_IFREG;
 356                inode->i_ctime = inode->i_atime = inode->i_mtime =
 357                                hfs_m_to_utime(rec->file.MdDat);
 358                inode->i_op = &hfs_file_inode_operations;
 359                inode->i_fop = &hfs_file_operations;
 360                inode->i_mapping->a_ops = &hfs_aops;
 361                break;
 362        case HFS_CDR_DIR:
 363                inode->i_ino = be32_to_cpu(rec->dir.DirID);
 364                inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
 365                HFS_I(inode)->fs_blocks = 0;
 366                inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
 367                inode->i_ctime = inode->i_atime = inode->i_mtime =
 368                                hfs_m_to_utime(rec->dir.MdDat);
 369                inode->i_op = &hfs_dir_inode_operations;
 370                inode->i_fop = &hfs_dir_operations;
 371                break;
 372        default:
 373                make_bad_inode(inode);
 374        }
 375        return 0;
 376}
 377
 378/*
 379 * __hfs_iget()
 380 *
 381 * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
 382 * the catalog B-tree and the 'type' of the desired file return the
 383 * inode for that file/directory or NULL.  Note that 'type' indicates
 384 * whether we want the actual file or directory, or the corresponding
 385 * metadata (AppleDouble header file or CAP metadata file).
 386 */
 387struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
 388{
 389        struct hfs_iget_data data = { key, rec };
 390        struct inode *inode;
 391        u32 cnid;
 392
 393        switch (rec->type) {
 394        case HFS_CDR_DIR:
 395                cnid = be32_to_cpu(rec->dir.DirID);
 396                break;
 397        case HFS_CDR_FIL:
 398                cnid = be32_to_cpu(rec->file.FlNum);
 399                break;
 400        default:
 401                return NULL;
 402        }
 403        inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
 404        if (inode && (inode->i_state & I_NEW))
 405                unlock_new_inode(inode);
 406        return inode;
 407}
 408
 409void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
 410                          __be32 *log_size, __be32 *phys_size)
 411{
 412        memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
 413
 414        if (log_size)
 415                *log_size = cpu_to_be32(inode->i_size);
 416        if (phys_size)
 417                *phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
 418                                         HFS_SB(inode->i_sb)->alloc_blksz);
 419}
 420
 421int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 422{
 423        struct inode *main_inode = inode;
 424        struct hfs_find_data fd;
 425        hfs_cat_rec rec;
 426        int res;
 427
 428        hfs_dbg(INODE, "hfs_write_inode: %lu\n", inode->i_ino);
 429        res = hfs_ext_write_extent(inode);
 430        if (res)
 431                return res;
 432
 433        if (inode->i_ino < HFS_FIRSTUSER_CNID) {
 434                switch (inode->i_ino) {
 435                case HFS_ROOT_CNID:
 436                        break;
 437                case HFS_EXT_CNID:
 438                        hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
 439                        return 0;
 440                case HFS_CAT_CNID:
 441                        hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
 442                        return 0;
 443                default:
 444                        BUG();
 445                        return -EIO;
 446                }
 447        }
 448
 449        if (HFS_IS_RSRC(inode))
 450                main_inode = HFS_I(inode)->rsrc_inode;
 451
 452        if (!main_inode->i_nlink)
 453                return 0;
 454
 455        if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
 456                /* panic? */
 457                return -EIO;
 458
 459        fd.search_key->cat = HFS_I(main_inode)->cat_key;
 460        if (hfs_brec_find(&fd))
 461                /* panic? */
 462                goto out;
 463
 464        if (S_ISDIR(main_inode->i_mode)) {
 465                if (fd.entrylength < sizeof(struct hfs_cat_dir))
 466                        /* panic? */;
 467                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 468                           sizeof(struct hfs_cat_dir));
 469                if (rec.type != HFS_CDR_DIR ||
 470                    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
 471                }
 472
 473                rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
 474                rec.dir.Val = cpu_to_be16(inode->i_size - 2);
 475
 476                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 477                            sizeof(struct hfs_cat_dir));
 478        } else if (HFS_IS_RSRC(inode)) {
 479                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 480                               sizeof(struct hfs_cat_file));
 481                hfs_inode_write_fork(inode, rec.file.RExtRec,
 482                                     &rec.file.RLgLen, &rec.file.RPyLen);
 483                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 484                                sizeof(struct hfs_cat_file));
 485        } else {
 486                if (fd.entrylength < sizeof(struct hfs_cat_file))
 487                        /* panic? */;
 488                hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
 489                           sizeof(struct hfs_cat_file));
 490                if (rec.type != HFS_CDR_FIL ||
 491                    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
 492                }
 493
 494                if (inode->i_mode & S_IWUSR)
 495                        rec.file.Flags &= ~HFS_FIL_LOCK;
 496                else
 497                        rec.file.Flags |= HFS_FIL_LOCK;
 498                hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
 499                rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
 500
 501                hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
 502                            sizeof(struct hfs_cat_file));
 503        }
 504out:
 505        hfs_find_exit(&fd);
 506        return 0;
 507}
 508
 509static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
 510                                      unsigned int flags)
 511{
 512        struct inode *inode = NULL;
 513        hfs_cat_rec rec;
 514        struct hfs_find_data fd;
 515        int res;
 516
 517        if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
 518                goto out;
 519
 520        inode = HFS_I(dir)->rsrc_inode;
 521        if (inode)
 522                goto out;
 523
 524        inode = new_inode(dir->i_sb);
 525        if (!inode)
 526                return ERR_PTR(-ENOMEM);
 527
 528        res = hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
 529        if (res) {
 530                iput(inode);
 531                return ERR_PTR(res);
 532        }
 533        fd.search_key->cat = HFS_I(dir)->cat_key;
 534        res = hfs_brec_read(&fd, &rec, sizeof(rec));
 535        if (!res) {
 536                struct hfs_iget_data idata = { NULL, &rec };
 537                hfs_read_inode(inode, &idata);
 538        }
 539        hfs_find_exit(&fd);
 540        if (res) {
 541                iput(inode);
 542                return ERR_PTR(res);
 543        }
 544        HFS_I(inode)->rsrc_inode = dir;
 545        HFS_I(dir)->rsrc_inode = inode;
 546        igrab(dir);
 547        inode_fake_hash(inode);
 548        mark_inode_dirty(inode);
 549        dont_mount(dentry);
 550out:
 551        return d_splice_alias(inode, dentry);
 552}
 553
 554void hfs_evict_inode(struct inode *inode)
 555{
 556        truncate_inode_pages_final(&inode->i_data);
 557        clear_inode(inode);
 558        if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
 559                HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
 560                iput(HFS_I(inode)->rsrc_inode);
 561        }
 562}
 563
 564static int hfs_file_open(struct inode *inode, struct file *file)
 565{
 566        if (HFS_IS_RSRC(inode))
 567                inode = HFS_I(inode)->rsrc_inode;
 568        atomic_inc(&HFS_I(inode)->opencnt);
 569        return 0;
 570}
 571
 572static int hfs_file_release(struct inode *inode, struct file *file)
 573{
 574        //struct super_block *sb = inode->i_sb;
 575
 576        if (HFS_IS_RSRC(inode))
 577                inode = HFS_I(inode)->rsrc_inode;
 578        if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {
 579                inode_lock(inode);
 580                hfs_file_truncate(inode);
 581                //if (inode->i_flags & S_DEAD) {
 582                //      hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
 583                //      hfs_delete_inode(inode);
 584                //}
 585                inode_unlock(inode);
 586        }
 587        return 0;
 588}
 589
 590/*
 591 * hfs_notify_change()
 592 *
 593 * Based very closely on fs/msdos/inode.c by Werner Almesberger
 594 *
 595 * This is the notify_change() field in the super_operations structure
 596 * for HFS file systems.  The purpose is to take that changes made to
 597 * an inode and apply then in a filesystem-dependent manner.  In this
 598 * case the process has a few of tasks to do:
 599 *  1) prevent changes to the i_uid and i_gid fields.
 600 *  2) map file permissions to the closest allowable permissions
 601 *  3) Since multiple Linux files can share the same on-disk inode under
 602 *     HFS (for instance the data and resource forks of a file) a change
 603 *     to permissions must be applied to all other in-core inodes which
 604 *     correspond to the same HFS file.
 605 */
 606
 607int hfs_inode_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
 608                      struct iattr *attr)
 609{
 610        struct inode *inode = d_inode(dentry);
 611        struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
 612        int error;
 613
 614        error = setattr_prepare(&init_user_ns, dentry,
 615                                attr); /* basic permission checks */
 616        if (error)
 617                return error;
 618
 619        /* no uig/gid changes and limit which mode bits can be set */
 620        if (((attr->ia_valid & ATTR_UID) &&
 621             (!uid_eq(attr->ia_uid, hsb->s_uid))) ||
 622            ((attr->ia_valid & ATTR_GID) &&
 623             (!gid_eq(attr->ia_gid, hsb->s_gid))) ||
 624            ((attr->ia_valid & ATTR_MODE) &&
 625             ((S_ISDIR(inode->i_mode) &&
 626               (attr->ia_mode != inode->i_mode)) ||
 627              (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
 628                return hsb->s_quiet ? 0 : error;
 629        }
 630
 631        if (attr->ia_valid & ATTR_MODE) {
 632                /* Only the 'w' bits can ever change and only all together. */
 633                if (attr->ia_mode & S_IWUSR)
 634                        attr->ia_mode = inode->i_mode | S_IWUGO;
 635                else
 636                        attr->ia_mode = inode->i_mode & ~S_IWUGO;
 637                attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
 638        }
 639
 640        if ((attr->ia_valid & ATTR_SIZE) &&
 641            attr->ia_size != i_size_read(inode)) {
 642                inode_dio_wait(inode);
 643
 644                error = inode_newsize_ok(inode, attr->ia_size);
 645                if (error)
 646                        return error;
 647
 648                truncate_setsize(inode, attr->ia_size);
 649                hfs_file_truncate(inode);
 650                inode->i_atime = inode->i_mtime = inode->i_ctime =
 651                                                  current_time(inode);
 652        }
 653
 654        setattr_copy(&init_user_ns, inode, attr);
 655        mark_inode_dirty(inode);
 656        return 0;
 657}
 658
 659static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
 660                          int datasync)
 661{
 662        struct inode *inode = filp->f_mapping->host;
 663        struct super_block * sb;
 664        int ret, err;
 665
 666        ret = file_write_and_wait_range(filp, start, end);
 667        if (ret)
 668                return ret;
 669        inode_lock(inode);
 670
 671        /* sync the inode to buffers */
 672        ret = write_inode_now(inode, 0);
 673
 674        /* sync the superblock to buffers */
 675        sb = inode->i_sb;
 676        flush_delayed_work(&HFS_SB(sb)->mdb_work);
 677        /* .. finally sync the buffers to disk */
 678        err = sync_blockdev(sb->s_bdev);
 679        if (!ret)
 680                ret = err;
 681        inode_unlock(inode);
 682        return ret;
 683}
 684
 685static const struct file_operations hfs_file_operations = {
 686        .llseek         = generic_file_llseek,
 687        .read_iter      = generic_file_read_iter,
 688        .write_iter     = generic_file_write_iter,
 689        .mmap           = generic_file_mmap,
 690        .splice_read    = generic_file_splice_read,
 691        .fsync          = hfs_file_fsync,
 692        .open           = hfs_file_open,
 693        .release        = hfs_file_release,
 694};
 695
 696static const struct inode_operations hfs_file_inode_operations = {
 697        .lookup         = hfs_file_lookup,
 698        .setattr        = hfs_inode_setattr,
 699        .listxattr      = generic_listxattr,
 700};
 701