/*
   *  linux/fs/hfs/inode.c
   *
   * Copyright (C) 1995-1997  Paul H. Hargrove
   * (C) 2003 Ardis Technologies <roman@ardistech.com>
   * This file may be distributed under the terms of the GNU General Public License.
   *
   * This file contains inode-related functions which do not depend on
   * which scheme is being used to represent forks.
   *
   * Based on the minix file system code, (C) 1991, 1992 by Linus Torvalds
   */
  
  #include <linux/pagemap.h>

  #include <linux/mpage.h>

  #include <linux/sched.h>

  
  #include "hfs_fs.h"
  #include "btree.h"

  static const struct file_operations hfs_file_operations;

  static const struct inode_operations hfs_file_inode_operations;

  
  /*================ Variable-like macros ================*/
  
  #define HFS_VALID_MODE_BITS  (S_IFREG | S_IFDIR | S_IRWXUGO)
  
  static int hfs_writepage(struct page *page, struct writeback_control *wbc)
  {
  	return block_write_full_page(page, hfs_get_block, wbc);
  }
  
  static int hfs_readpage(struct file *file, struct page *page)
  {
  	return block_read_full_page(page, hfs_get_block);
  }

  static int hfs_write_begin(struct file *file, struct address_space *mapping,
  			loff_t pos, unsigned len, unsigned flags,
  			struct page **pagep, void **fsdata)

  {

  	int ret;

  	*pagep = NULL;

  	ret = cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,

  				hfs_get_block,
  				&HFS_I(mapping->host)->phys_size);

  	if (unlikely(ret)) {
  		loff_t isize = mapping->host->i_size;
  		if (pos + len > isize)
  			vmtruncate(mapping->host, isize);
  	}
  
  	return ret;

  }
  
  static sector_t hfs_bmap(struct address_space *mapping, sector_t block)
  {
  	return generic_block_bmap(mapping, block, hfs_get_block);
  }

  static int hfs_releasepage(struct page *page, gfp_t mask)

  {
  	struct inode *inode = page->mapping->host;
  	struct super_block *sb = inode->i_sb;
  	struct hfs_btree *tree;
  	struct hfs_bnode *node;
  	u32 nidx;
  	int i, res = 1;
  
  	switch (inode->i_ino) {
  	case HFS_EXT_CNID:
  		tree = HFS_SB(sb)->ext_tree;
  		break;
  	case HFS_CAT_CNID:
  		tree = HFS_SB(sb)->cat_tree;
  		break;
  	default:
  		BUG();
  		return 0;
  	}

  
  	if (!tree)
  		return 0;

  	if (tree->node_size >= PAGE_CACHE_SIZE) {
  		nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
  		spin_lock(&tree->hash_lock);
  		node = hfs_bnode_findhash(tree, nidx);
  		if (!node)
  			;
  		else if (atomic_read(&node->refcnt))
  			res = 0;
  		if (res && node) {
  			hfs_bnode_unhash(node);
  			hfs_bnode_free(node);
  		}
  		spin_unlock(&tree->hash_lock);
  	} else {
  		nidx = page->index << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  		i = 1 << (PAGE_CACHE_SHIFT - tree->node_size_shift);
  		spin_lock(&tree->hash_lock);
  		do {
  			node = hfs_bnode_findhash(tree, nidx++);
  			if (!node)
  				continue;
  			if (atomic_read(&node->refcnt)) {
  				res = 0;
  				break;
  			}
  			hfs_bnode_unhash(node);
  			hfs_bnode_free(node);
  		} while (--i && nidx < tree->node_count);
  		spin_unlock(&tree->hash_lock);
  	}

  	return res ? try_to_free_buffers(page) : 0;
  }

  static ssize_t hfs_direct_IO(int rw, struct kiocb *iocb,
  		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
  {
  	struct file *file = iocb->ki_filp;

  	struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;

  	ssize_t ret;

  	ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
  				 hfs_get_block);

  
  	/*
  	 * In case of error extending write may have instantiated a few
  	 * blocks outside i_size. Trim these off again.
  	 */
  	if (unlikely((rw & WRITE) && ret < 0)) {
  		loff_t isize = i_size_read(inode);
  		loff_t end = offset + iov_length(iov, nr_segs);
  
  		if (end > isize)
  			vmtruncate(inode, isize);
  	}
  
  	return ret;

  }
  
  static int hfs_writepages(struct address_space *mapping,
  			  struct writeback_control *wbc)
  {
  	return mpage_writepages(mapping, wbc, hfs_get_block);
  }

  const struct address_space_operations hfs_btree_aops = {

  	.readpage	= hfs_readpage,
  	.writepage	= hfs_writepage,

  	.write_begin	= hfs_write_begin,
  	.write_end	= generic_write_end,

  	.bmap		= hfs_bmap,
  	.releasepage	= hfs_releasepage,
  };

  const struct address_space_operations hfs_aops = {

  	.readpage	= hfs_readpage,
  	.writepage	= hfs_writepage,

  	.write_begin	= hfs_write_begin,
  	.write_end	= generic_write_end,

  	.bmap		= hfs_bmap,
  	.direct_IO	= hfs_direct_IO,
  	.writepages	= hfs_writepages,
  };
  
  /*
   * hfs_new_inode
   */

  struct inode *hfs_new_inode(struct inode *dir, struct qstr *name, umode_t mode)

  {
  	struct super_block *sb = dir->i_sb;
  	struct inode *inode = new_inode(sb);
  	if (!inode)
  		return NULL;

  	mutex_init(&HFS_I(inode)->extents_lock);

  	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);

  	hfs_cat_build_key(sb, (btree_key *)&HFS_I(inode)->cat_key, dir->i_ino, name);

  	inode->i_ino = HFS_SB(sb)->next_id++;
  	inode->i_mode = mode;

  	inode->i_uid = current_fsuid();
  	inode->i_gid = current_fsgid();

  	set_nlink(inode, 1);

  	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;

  	HFS_I(inode)->flags = 0;
  	HFS_I(inode)->rsrc_inode = NULL;
  	HFS_I(inode)->fs_blocks = 0;
  	if (S_ISDIR(mode)) {
  		inode->i_size = 2;
  		HFS_SB(sb)->folder_count++;
  		if (dir->i_ino == HFS_ROOT_CNID)
  			HFS_SB(sb)->root_dirs++;
  		inode->i_op = &hfs_dir_inode_operations;
  		inode->i_fop = &hfs_dir_operations;
  		inode->i_mode |= S_IRWXUGO;
  		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_dir_umask;
  	} else if (S_ISREG(mode)) {
  		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
  		HFS_SB(sb)->file_count++;
  		if (dir->i_ino == HFS_ROOT_CNID)
  			HFS_SB(sb)->root_files++;
  		inode->i_op = &hfs_file_inode_operations;
  		inode->i_fop = &hfs_file_operations;
  		inode->i_mapping->a_ops = &hfs_aops;
  		inode->i_mode |= S_IRUGO|S_IXUGO;
  		if (mode & S_IWUSR)
  			inode->i_mode |= S_IWUGO;
  		inode->i_mode &= ~HFS_SB(inode->i_sb)->s_file_umask;
  		HFS_I(inode)->phys_size = 0;
  		HFS_I(inode)->alloc_blocks = 0;
  		HFS_I(inode)->first_blocks = 0;
  		HFS_I(inode)->cached_start = 0;
  		HFS_I(inode)->cached_blocks = 0;
  		memset(HFS_I(inode)->first_extents, 0, sizeof(hfs_extent_rec));
  		memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
  	}
  	insert_inode_hash(inode);
  	mark_inode_dirty(inode);
  	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
  	sb->s_dirt = 1;
  
  	return inode;
  }
  
  void hfs_delete_inode(struct inode *inode)
  {
  	struct super_block *sb = inode->i_sb;
  
  	dprint(DBG_INODE, "delete_inode: %lu
  ", inode->i_ino);
  	if (S_ISDIR(inode->i_mode)) {
  		HFS_SB(sb)->folder_count--;
  		if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
  			HFS_SB(sb)->root_dirs--;
  		set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
  		sb->s_dirt = 1;
  		return;
  	}
  	HFS_SB(sb)->file_count--;
  	if (HFS_I(inode)->cat_key.ParID == cpu_to_be32(HFS_ROOT_CNID))
  		HFS_SB(sb)->root_files--;
  	if (S_ISREG(inode->i_mode)) {
  		if (!inode->i_nlink) {
  			inode->i_size = 0;
  			hfs_file_truncate(inode);
  		}
  	}
  	set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
  	sb->s_dirt = 1;
  }
  
  void hfs_inode_read_fork(struct inode *inode, struct hfs_extent *ext,
  			 __be32 __log_size, __be32 phys_size, u32 clump_size)
  {
  	struct super_block *sb = inode->i_sb;
  	u32 log_size = be32_to_cpu(__log_size);
  	u16 count;
  	int i;
  
  	memcpy(HFS_I(inode)->first_extents, ext, sizeof(hfs_extent_rec));
  	for (count = 0, i = 0; i < 3; i++)
  		count += be16_to_cpu(ext[i].count);
  	HFS_I(inode)->first_blocks = count;
  
  	inode->i_size = HFS_I(inode)->phys_size = log_size;
  	HFS_I(inode)->fs_blocks = (log_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits;
  	inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits);
  	HFS_I(inode)->alloc_blocks = be32_to_cpu(phys_size) /
  				     HFS_SB(sb)->alloc_blksz;
  	HFS_I(inode)->clump_blocks = clump_size / HFS_SB(sb)->alloc_blksz;
  	if (!HFS_I(inode)->clump_blocks)
  		HFS_I(inode)->clump_blocks = HFS_SB(sb)->clumpablks;
  }
  
  struct hfs_iget_data {
  	struct hfs_cat_key *key;
  	hfs_cat_rec *rec;
  };
  
  static int hfs_test_inode(struct inode *inode, void *data)
  {
  	struct hfs_iget_data *idata = data;
  	hfs_cat_rec *rec;
  
  	rec = idata->rec;
  	switch (rec->type) {
  	case HFS_CDR_DIR:
  		return inode->i_ino == be32_to_cpu(rec->dir.DirID);
  	case HFS_CDR_FIL:
  		return inode->i_ino == be32_to_cpu(rec->file.FlNum);
  	default:
  		BUG();
  		return 1;
  	}
  }
  
  /*
   * hfs_read_inode
   */
  static int hfs_read_inode(struct inode *inode, void *data)
  {
  	struct hfs_iget_data *idata = data;
  	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
  	hfs_cat_rec *rec;
  
  	HFS_I(inode)->flags = 0;
  	HFS_I(inode)->rsrc_inode = NULL;

  	mutex_init(&HFS_I(inode)->extents_lock);

  	INIT_LIST_HEAD(&HFS_I(inode)->open_dir_list);
  
  	/* Initialize the inode */
  	inode->i_uid = hsb->s_uid;
  	inode->i_gid = hsb->s_gid;

  	set_nlink(inode, 1);

  
  	if (idata->key)
  		HFS_I(inode)->cat_key = *idata->key;
  	else
  		HFS_I(inode)->flags |= HFS_FLG_RSRC;
  	HFS_I(inode)->tz_secondswest = sys_tz.tz_minuteswest * 60;
  
  	rec = idata->rec;
  	switch (rec->type) {
  	case HFS_CDR_FIL:
  		if (!HFS_IS_RSRC(inode)) {
  			hfs_inode_read_fork(inode, rec->file.ExtRec, rec->file.LgLen,
  					    rec->file.PyLen, be16_to_cpu(rec->file.ClpSize));
  		} else {
  			hfs_inode_read_fork(inode, rec->file.RExtRec, rec->file.RLgLen,
  					    rec->file.RPyLen, be16_to_cpu(rec->file.ClpSize));
  		}
  
  		inode->i_ino = be32_to_cpu(rec->file.FlNum);
  		inode->i_mode = S_IRUGO | S_IXUGO;
  		if (!(rec->file.Flags & HFS_FIL_LOCK))
  			inode->i_mode |= S_IWUGO;
  		inode->i_mode &= ~hsb->s_file_umask;
  		inode->i_mode |= S_IFREG;
  		inode->i_ctime = inode->i_atime = inode->i_mtime =
  				hfs_m_to_utime(rec->file.MdDat);
  		inode->i_op = &hfs_file_inode_operations;
  		inode->i_fop = &hfs_file_operations;
  		inode->i_mapping->a_ops = &hfs_aops;
  		break;
  	case HFS_CDR_DIR:
  		inode->i_ino = be32_to_cpu(rec->dir.DirID);
  		inode->i_size = be16_to_cpu(rec->dir.Val) + 2;
  		HFS_I(inode)->fs_blocks = 0;
  		inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask);
  		inode->i_ctime = inode->i_atime = inode->i_mtime =
  				hfs_m_to_utime(rec->dir.MdDat);
  		inode->i_op = &hfs_dir_inode_operations;
  		inode->i_fop = &hfs_dir_operations;
  		break;
  	default:
  		make_bad_inode(inode);
  	}
  	return 0;
  }
  
  /*
   * __hfs_iget()
   *
   * Given the MDB for a HFS filesystem, a 'key' and an 'entry' in
   * the catalog B-tree and the 'type' of the desired file return the
   * inode for that file/directory or NULL.  Note that 'type' indicates
   * whether we want the actual file or directory, or the corresponding
   * metadata (AppleDouble header file or CAP metadata file).
   */
  struct inode *hfs_iget(struct super_block *sb, struct hfs_cat_key *key, hfs_cat_rec *rec)
  {
  	struct hfs_iget_data data = { key, rec };
  	struct inode *inode;
  	u32 cnid;
  
  	switch (rec->type) {
  	case HFS_CDR_DIR:
  		cnid = be32_to_cpu(rec->dir.DirID);
  		break;
  	case HFS_CDR_FIL:
  		cnid = be32_to_cpu(rec->file.FlNum);
  		break;
  	default:
  		return NULL;
  	}
  	inode = iget5_locked(sb, cnid, hfs_test_inode, hfs_read_inode, &data);
  	if (inode && (inode->i_state & I_NEW))
  		unlock_new_inode(inode);
  	return inode;
  }
  
  void hfs_inode_write_fork(struct inode *inode, struct hfs_extent *ext,
  			  __be32 *log_size, __be32 *phys_size)
  {
  	memcpy(ext, HFS_I(inode)->first_extents, sizeof(hfs_extent_rec));
  
  	if (log_size)
  		*log_size = cpu_to_be32(inode->i_size);
  	if (phys_size)
  		*phys_size = cpu_to_be32(HFS_I(inode)->alloc_blocks *
  					 HFS_SB(inode->i_sb)->alloc_blksz);
  }

  int hfs_write_inode(struct inode *inode, struct writeback_control *wbc)

  {
  	struct inode *main_inode = inode;
  	struct hfs_find_data fd;
  	hfs_cat_rec rec;
  
  	dprint(DBG_INODE, "hfs_write_inode: %lu
  ", inode->i_ino);
  	hfs_ext_write_extent(inode);
  
  	if (inode->i_ino < HFS_FIRSTUSER_CNID) {
  		switch (inode->i_ino) {
  		case HFS_ROOT_CNID:
  			break;
  		case HFS_EXT_CNID:
  			hfs_btree_write(HFS_SB(inode->i_sb)->ext_tree);
  			return 0;
  		case HFS_CAT_CNID:
  			hfs_btree_write(HFS_SB(inode->i_sb)->cat_tree);
  			return 0;
  		default:
  			BUG();
  			return -EIO;
  		}
  	}
  
  	if (HFS_IS_RSRC(inode))
  		main_inode = HFS_I(inode)->rsrc_inode;
  
  	if (!main_inode->i_nlink)
  		return 0;
  
  	if (hfs_find_init(HFS_SB(main_inode->i_sb)->cat_tree, &fd))
  		/* panic? */
  		return -EIO;
  
  	fd.search_key->cat = HFS_I(main_inode)->cat_key;
  	if (hfs_brec_find(&fd))
  		/* panic? */
  		goto out;
  
  	if (S_ISDIR(main_inode->i_mode)) {
  		if (fd.entrylength < sizeof(struct hfs_cat_dir))
  			/* panic? */;
  		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
  			   sizeof(struct hfs_cat_dir));
  		if (rec.type != HFS_CDR_DIR ||
  		    be32_to_cpu(rec.dir.DirID) != inode->i_ino) {
  		}
  
  		rec.dir.MdDat = hfs_u_to_mtime(inode->i_mtime);
  		rec.dir.Val = cpu_to_be16(inode->i_size - 2);
  
  		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
  			    sizeof(struct hfs_cat_dir));
  	} else if (HFS_IS_RSRC(inode)) {
  		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
  			       sizeof(struct hfs_cat_file));
  		hfs_inode_write_fork(inode, rec.file.RExtRec,
  				     &rec.file.RLgLen, &rec.file.RPyLen);
  		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
  				sizeof(struct hfs_cat_file));
  	} else {
  		if (fd.entrylength < sizeof(struct hfs_cat_file))
  			/* panic? */;
  		hfs_bnode_read(fd.bnode, &rec, fd.entryoffset,
  			   sizeof(struct hfs_cat_file));
  		if (rec.type != HFS_CDR_FIL ||
  		    be32_to_cpu(rec.file.FlNum) != inode->i_ino) {
  		}
  
  		if (inode->i_mode & S_IWUSR)
  			rec.file.Flags &= ~HFS_FIL_LOCK;
  		else
  			rec.file.Flags |= HFS_FIL_LOCK;
  		hfs_inode_write_fork(inode, rec.file.ExtRec, &rec.file.LgLen, &rec.file.PyLen);
  		rec.file.MdDat = hfs_u_to_mtime(inode->i_mtime);
  
  		hfs_bnode_write(fd.bnode, &rec, fd.entryoffset,
  			    sizeof(struct hfs_cat_file));
  	}
  out:
  	hfs_find_exit(&fd);
  	return 0;
  }
  
  static struct dentry *hfs_file_lookup(struct inode *dir, struct dentry *dentry,
  				      struct nameidata *nd)
  {
  	struct inode *inode = NULL;
  	hfs_cat_rec rec;
  	struct hfs_find_data fd;
  	int res;
  
  	if (HFS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc"))
  		goto out;
  
  	inode = HFS_I(dir)->rsrc_inode;
  	if (inode)
  		goto out;
  
  	inode = new_inode(dir->i_sb);
  	if (!inode)
  		return ERR_PTR(-ENOMEM);
  
  	hfs_find_init(HFS_SB(dir->i_sb)->cat_tree, &fd);
  	fd.search_key->cat = HFS_I(dir)->cat_key;
  	res = hfs_brec_read(&fd, &rec, sizeof(rec));
  	if (!res) {
  		struct hfs_iget_data idata = { NULL, &rec };
  		hfs_read_inode(inode, &idata);
  	}
  	hfs_find_exit(&fd);
  	if (res) {
  		iput(inode);
  		return ERR_PTR(res);
  	}
  	HFS_I(inode)->rsrc_inode = dir;
  	HFS_I(dir)->rsrc_inode = inode;
  	igrab(dir);

  	hlist_add_fake(&inode->i_hash);

  	mark_inode_dirty(inode);
  out:
  	d_add(dentry, inode);
  	return NULL;
  }

  void hfs_evict_inode(struct inode *inode)

  {

  	truncate_inode_pages(&inode->i_data, 0);
  	end_writeback(inode);

  	if (HFS_IS_RSRC(inode) && HFS_I(inode)->rsrc_inode) {
  		HFS_I(HFS_I(inode)->rsrc_inode)->rsrc_inode = NULL;
  		iput(HFS_I(inode)->rsrc_inode);
  	}
  }

  static int hfs_file_open(struct inode *inode, struct file *file)
  {
  	if (HFS_IS_RSRC(inode))
  		inode = HFS_I(inode)->rsrc_inode;

  	atomic_inc(&HFS_I(inode)->opencnt);
  	return 0;
  }
  
  static int hfs_file_release(struct inode *inode, struct file *file)
  {
  	//struct super_block *sb = inode->i_sb;
  
  	if (HFS_IS_RSRC(inode))
  		inode = HFS_I(inode)->rsrc_inode;

  	if (atomic_dec_and_test(&HFS_I(inode)->opencnt)) {

  		mutex_lock(&inode->i_mutex);

  		hfs_file_truncate(inode);
  		//if (inode->i_flags & S_DEAD) {
  		//	hfs_delete_cat(inode->i_ino, HFSPLUS_SB(sb).hidden_dir, NULL);
  		//	hfs_delete_inode(inode);
  		//}

  		mutex_unlock(&inode->i_mutex);

  	}
  	return 0;
  }
  
  /*
   * hfs_notify_change()
   *
   * Based very closely on fs/msdos/inode.c by Werner Almesberger
   *
   * This is the notify_change() field in the super_operations structure
   * for HFS file systems.  The purpose is to take that changes made to
   * an inode and apply then in a filesystem-dependent manner.  In this
   * case the process has a few of tasks to do:
   *  1) prevent changes to the i_uid and i_gid fields.
   *  2) map file permissions to the closest allowable permissions
   *  3) Since multiple Linux files can share the same on-disk inode under
   *     HFS (for instance the data and resource forks of a file) a change
   *     to permissions must be applied to all other in-core inodes which
   *     correspond to the same HFS file.
   */
  
  int hfs_inode_setattr(struct dentry *dentry, struct iattr * attr)
  {
  	struct inode *inode = dentry->d_inode;
  	struct hfs_sb_info *hsb = HFS_SB(inode->i_sb);
  	int error;
  
  	error = inode_change_ok(inode, attr); /* basic permission checks */
  	if (error)
  		return error;
  
  	/* no uig/gid changes and limit which mode bits can be set */
  	if (((attr->ia_valid & ATTR_UID) &&
  	     (attr->ia_uid != hsb->s_uid)) ||
  	    ((attr->ia_valid & ATTR_GID) &&
  	     (attr->ia_gid != hsb->s_gid)) ||
  	    ((attr->ia_valid & ATTR_MODE) &&
  	     ((S_ISDIR(inode->i_mode) &&
  	       (attr->ia_mode != inode->i_mode)) ||
  	      (attr->ia_mode & ~HFS_VALID_MODE_BITS)))) {
  		return hsb->s_quiet ? 0 : error;
  	}
  
  	if (attr->ia_valid & ATTR_MODE) {
  		/* Only the 'w' bits can ever change and only all together. */
  		if (attr->ia_mode & S_IWUSR)
  			attr->ia_mode = inode->i_mode | S_IWUGO;
  		else
  			attr->ia_mode = inode->i_mode & ~S_IWUGO;
  		attr->ia_mode &= S_ISDIR(inode->i_mode) ? ~hsb->s_dir_umask: ~hsb->s_file_umask;
  	}

  	if ((attr->ia_valid & ATTR_SIZE) &&
  	    attr->ia_size != i_size_read(inode)) {

  		inode_dio_wait(inode);

  		error = vmtruncate(inode, attr->ia_size);
  		if (error)
  			return error;
  	}
  
  	setattr_copy(inode, attr);
  	mark_inode_dirty(inode);

  	return 0;
  }

  static int hfs_file_fsync(struct file *filp, loff_t start, loff_t end,
  			  int datasync)

  {
  	struct inode *inode = filp->f_mapping->host;
  	struct super_block * sb;
  	int ret, err;

  	ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
  	if (ret)
  		return ret;
  	mutex_lock(&inode->i_mutex);

  	/* sync the inode to buffers */
  	ret = write_inode_now(inode, 0);
  
  	/* sync the superblock to buffers */
  	sb = inode->i_sb;
  	if (sb->s_dirt) {
  		lock_super(sb);
  		sb->s_dirt = 0;
  		if (!(sb->s_flags & MS_RDONLY))
  			hfs_mdb_commit(sb);
  		unlock_super(sb);
  	}
  	/* .. finally sync the buffers to disk */
  	err = sync_blockdev(sb->s_bdev);
  	if (!ret)
  		ret = err;

  	mutex_unlock(&inode->i_mutex);

  	return ret;
  }

  static const struct file_operations hfs_file_operations = {

  	.llseek		= generic_file_llseek,

  	.read		= do_sync_read,
  	.aio_read	= generic_file_aio_read,
  	.write		= do_sync_write,
  	.aio_write	= generic_file_aio_write,

  	.mmap		= generic_file_mmap,

  	.splice_read	= generic_file_splice_read,

  	.fsync		= hfs_file_fsync,

  	.open		= hfs_file_open,
  	.release	= hfs_file_release,
  };

  static const struct inode_operations hfs_file_inode_operations = {

  	.lookup		= hfs_file_lookup,
  	.truncate	= hfs_file_truncate,
  	.setattr	= hfs_inode_setattr,

  	.setxattr	= hfs_setxattr,
  	.getxattr	= hfs_getxattr,
  	.listxattr	= hfs_listxattr,
  };