diff --git a/include/mft.h b/include/mft.h index e69de29b..5f8fa21b 100644 --- a/include/mft.h +++ b/include/mft.h @@ -0,0 +1,106 @@ +/* + * $Id$ + * + * mft.h - Exports for MFT record handling. Part of the Linux-NTFS project. + * + * Copyright (c) 2000-2002 Anton Altaparmakov. + * + * This program/include file is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as published + * by the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program/include file is distributed in the hope that it will be + * useful, but WITHOUT ANY WARRANTY; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (in the main directory of the Linux-NTFS + * distribution in the file COPYING); if not, write to the Free Software + * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef _NTFS_MFT_H +#define _NTFS_MFT_H + +#include "volume.h" +#include "layout.h" + +extern int ntfs_read_mft_records(const ntfs_volume *vol, const MFT_REF mref, + const s64 count, MFT_RECORD *b); + +/** + * ntfs_read_mft_record - read a record from the mft + * @vol: volume to read from + * @mref: mft record number to read + * @b: output data buffer + * + * Read the mft record specified by @mref from volume @vol into buffer @b. + * Return 0 on success or -1 on error, with errno set to the error code. + * + * The read mft record is mst deprotected and is hence ready to use. The caller + * should check the record with is_baad_record() in case mst deprotection + * failed. + * + * NOTE: @b has to be at least of size vol->mft_record_size. + */ +static __inline__ int ntfs_read_mft_record(const ntfs_volume *vol, + const MFT_REF mref, MFT_RECORD *b) +{ + return ntfs_read_mft_records(vol, mref, 1, b); +} + +extern int ntfs_read_file_record(const ntfs_volume *vol, const MFT_REF mref, + MFT_RECORD **mrec, ATTR_RECORD **attr); + +extern int ntfs_write_mft_records(const ntfs_volume *vol, const MFT_REF mref, + const s64 count, MFT_RECORD *b); + +/** + * ntfs_write_mft_record - write an mft record to disk + * @vol: volume to write to + * @mref: mft record number to write + * @b: data buffer containing the mft record to write + * + * Write the mft record specified by @mref from buffer @b to volume @vol. + * Return 0 on success or -1 on error, with errno set to the error code. + * + * Before the mft record is written, it is mst protected. After the write, it + * is deprotected again, thus resulting in an increase in the update sequence + * number inside the buffer @b. + * + * NOTE: @b has to be at least of size vol->mft_record_size. + */ +static __inline__ int ntfs_write_mft_record(const ntfs_volume *vol, + const MFT_REF mref, MFT_RECORD *b) +{ + return ntfs_write_mft_records(vol, mref, 1, b); +} + +/** + * ntfs_get_mft_record_data_size - return number of bytes used in mft record @b + * @m: mft record to get the data size of + * + * Takes the mft record @m and returns the number of bytes used in the record + * or 0 on error (i.e. @m is not a valid mft record). Zero is not a valid size + * for an mft record as it at least has to have the MFT_RECORD, thus making the + * minimum size: + * (sizeof(MFT_RECORD) + 7) & ~7 + sizeof(ATTR_TYPES) = 52 bytes + * Aside: The 8-byte alignment and the 4 bytes for the attribute type are needed + * as each mft record has to have a list of attributes even if it only contains + * the attribute $END which doesn't contain anything else apart from its type. + * Also, you would expect every mft record to contain an update sequence array + * as well but that could in theory be non-existent (don't know if Windows' + * NTFS driver/chkdsk wouldn't view this as corruption in itself though). + */ +static __inline__ u32 ntfs_get_mft_record_data_size(const MFT_RECORD *m) +{ + if (!m || !is_mft_record(m->magic)) + return 0; + /* Get the number of used bytes and return it. */ + return le32_to_cpu(m->bytes_in_use); +} + +#endif /* defined _NTFS_MFT_H */ +