NTFS: Update attribute definition handling.

[safe/jmp/linux-2.6] / fs / ntfs / layout.h

/*
 * layout.h - All NTFS associated on-disk structures. Part of the Linux-NTFS
 *            project.
 *
 * Copyright (c) 2001-2005 Anton Altaparmakov
 * Copyright (c) 2002 Richard Russon
 *
 * 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 _LINUX_NTFS_LAYOUT_H
#define _LINUX_NTFS_LAYOUT_H

#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/list.h>
#include <asm/byteorder.h>

#include "types.h"

/*
 * Constant endianness conversion defines.
 */
#define const_le16_to_cpu(x)    __constant_le16_to_cpu(x)
#define const_le32_to_cpu(x)    __constant_le32_to_cpu(x)
#define const_le64_to_cpu(x)    __constant_le64_to_cpu(x)

#define const_cpu_to_le16(x)    __constant_cpu_to_le16(x)
#define const_cpu_to_le32(x)    __constant_cpu_to_le32(x)
#define const_cpu_to_le64(x)    __constant_cpu_to_le64(x)

/* The NTFS oem_id "NTFS    " */
#define magicNTFS       const_cpu_to_le64(0x202020205346544eULL)

/*
 * Location of bootsector on partition:
 *      The standard NTFS_BOOT_SECTOR is on sector 0 of the partition.
 *      On NT4 and above there is one backup copy of the boot sector to
 *      be found on the last sector of the partition (not normally accessible
 *      from within Windows as the bootsector contained number of sectors
 *      value is one less than the actual value!).
 *      On versions of NT 3.51 and earlier, the backup copy was located at
 *      number of sectors/2 (integer divide), i.e. in the middle of the volume.
 */

/*
 * BIOS parameter block (bpb) structure.
 */
typedef struct {
        le16 bytes_per_sector;          /* Size of a sector in bytes. */
        u8  sectors_per_cluster;        /* Size of a cluster in sectors. */
        le16 reserved_sectors;          /* zero */
        u8  fats;                       /* zero */
        le16 root_entries;              /* zero */
        le16 sectors;                   /* zero */
        u8  media_type;                 /* 0xf8 = hard disk */
        le16 sectors_per_fat;           /* zero */
        le16 sectors_per_track;         /* irrelevant */
        le16 heads;                     /* irrelevant */
        le32 hidden_sectors;            /* zero */
        le32 large_sectors;             /* zero */
} __attribute__ ((__packed__)) BIOS_PARAMETER_BLOCK;

/*
 * NTFS boot sector structure.
 */
typedef struct {
        u8  jump[3];                    /* Irrelevant (jump to boot up code).*/
        le64 oem_id;                    /* Magic "NTFS    ". */
        BIOS_PARAMETER_BLOCK bpb;       /* See BIOS_PARAMETER_BLOCK. */
        u8  unused[4];                  /* zero, NTFS diskedit.exe states that
                                           this is actually:
                                                __u8 physical_drive;    // 0x80
                                                __u8 current_head;      // zero
                                                __u8 extended_boot_signature;
                                                                        // 0x80
                                                __u8 unused;            // zero
                                         */
/*0x28*/sle64 number_of_sectors;        /* Number of sectors in volume. Gives
                                           maximum volume size of 2^63 sectors.
                                           Assuming standard sector size of 512
                                           bytes, the maximum byte size is
                                           approx. 4.7x10^21 bytes. (-; */
        sle64 mft_lcn;                  /* Cluster location of mft data. */
        sle64 mftmirr_lcn;              /* Cluster location of copy of mft. */
        s8  clusters_per_mft_record;    /* Mft record size in clusters. */
        u8  reserved0[3];               /* zero */
        s8  clusters_per_index_record;  /* Index block size in clusters. */
        u8  reserved1[3];               /* zero */
        le64 volume_serial_number;      /* Irrelevant (serial number). */
        le32 checksum;                  /* Boot sector checksum. */
/*0x54*/u8  bootstrap[426];             /* Irrelevant (boot up code). */
        le16 end_of_sector_marker;      /* End of bootsector magic. Always is
                                           0xaa55 in little endian. */
/* sizeof() = 512 (0x200) bytes */
} __attribute__ ((__packed__)) NTFS_BOOT_SECTOR;

/*
 * Magic identifiers present at the beginning of all ntfs record containing
 * records (like mft records for example).
 */
enum {
        /* Found in $MFT/$DATA. */
        magic_FILE = const_cpu_to_le32(0x454c4946), /* Mft entry. */
        magic_INDX = const_cpu_to_le32(0x58444e49), /* Index buffer. */
        magic_HOLE = const_cpu_to_le32(0x454c4f48), /* ? (NTFS 3.0+?) */

        /* Found in $LogFile/$DATA. */
        magic_RSTR = const_cpu_to_le32(0x52545352), /* Restart page. */
        magic_RCRD = const_cpu_to_le32(0x44524352), /* Log record page. */

        /* Found in $LogFile/$DATA.  (May be found in $MFT/$DATA, also?) */
        magic_CHKD = const_cpu_to_le32(0x424b4843), /* Modified by chkdsk. */

        /* Found in all ntfs record containing records. */
        magic_BAAD = const_cpu_to_le32(0x44414142), /* Failed multi sector
                                                       transfer was detected. */
        /*
         * Found in $LogFile/$DATA when a page is full of 0xff bytes and is
         * thus not initialized.  Page must be initialized before using it.
         */
        magic_empty = const_cpu_to_le32(0xffffffff) /* Record is empty. */
};

typedef le32 NTFS_RECORD_TYPE;

/*
 * Generic magic comparison macros. Finally found a use for the ## preprocessor
 * operator! (-8
 */

static inline BOOL __ntfs_is_magic(le32 x, NTFS_RECORD_TYPE r)
{
        return (x == r);
}
#define ntfs_is_magic(x, m)     __ntfs_is_magic(x, magic_##m)

static inline BOOL __ntfs_is_magicp(le32 *p, NTFS_RECORD_TYPE r)
{
        return (*p == r);
}
#define ntfs_is_magicp(p, m)    __ntfs_is_magicp(p, magic_##m)

/*
 * Specialised magic comparison macros for the NTFS_RECORD_TYPEs defined above.
 */
#define ntfs_is_file_record(x)          ( ntfs_is_magic (x, FILE) )
#define ntfs_is_file_recordp(p)         ( ntfs_is_magicp(p, FILE) )
#define ntfs_is_mft_record(x)           ( ntfs_is_file_record (x) )
#define ntfs_is_mft_recordp(p)          ( ntfs_is_file_recordp(p) )
#define ntfs_is_indx_record(x)          ( ntfs_is_magic (x, INDX) )
#define ntfs_is_indx_recordp(p)         ( ntfs_is_magicp(p, INDX) )
#define ntfs_is_hole_record(x)          ( ntfs_is_magic (x, HOLE) )
#define ntfs_is_hole_recordp(p)         ( ntfs_is_magicp(p, HOLE) )

#define ntfs_is_rstr_record(x)          ( ntfs_is_magic (x, RSTR) )
#define ntfs_is_rstr_recordp(p)         ( ntfs_is_magicp(p, RSTR) )
#define ntfs_is_rcrd_record(x)          ( ntfs_is_magic (x, RCRD) )
#define ntfs_is_rcrd_recordp(p)         ( ntfs_is_magicp(p, RCRD) )

#define ntfs_is_chkd_record(x)          ( ntfs_is_magic (x, CHKD) )
#define ntfs_is_chkd_recordp(p)         ( ntfs_is_magicp(p, CHKD) )

#define ntfs_is_baad_record(x)          ( ntfs_is_magic (x, BAAD) )
#define ntfs_is_baad_recordp(p)         ( ntfs_is_magicp(p, BAAD) )

#define ntfs_is_empty_record(x)         ( ntfs_is_magic (x, empty) )
#define ntfs_is_empty_recordp(p)        ( ntfs_is_magicp(p, empty) )

/*
 * The Update Sequence Array (usa) is an array of the le16 values which belong
 * to the end of each sector protected by the update sequence record in which
 * this array is contained. Note that the first entry is the Update Sequence
 * Number (usn), a cyclic counter of how many times the protected record has
 * been written to disk. The values 0 and -1 (ie. 0xffff) are not used. All
 * last le16's of each sector have to be equal to the usn (during reading) or
 * are set to it (during writing). If they are not, an incomplete multi sector
 * transfer has occurred when the data was written.
 * The maximum size for the update sequence array is fixed to:
 *      maximum size = usa_ofs + (usa_count * 2) = 510 bytes
 * The 510 bytes comes from the fact that the last le16 in the array has to
 * (obviously) finish before the last le16 of the first 512-byte sector.
 * This formula can be used as a consistency check in that usa_ofs +
 * (usa_count * 2) has to be less than or equal to 510.
 */
typedef struct {
        NTFS_RECORD_TYPE magic; /* A four-byte magic identifying the record
                                   type and/or status. */
        le16 usa_ofs;           /* Offset to the Update Sequence Array (usa)
                                   from the start of the ntfs record. */
        le16 usa_count;         /* Number of le16 sized entries in the usa
                                   including the Update Sequence Number (usn),
                                   thus the number of fixups is the usa_count
                                   minus 1. */
} __attribute__ ((__packed__)) NTFS_RECORD;

/*
 * System files mft record numbers. All these files are always marked as used
 * in the bitmap attribute of the mft; presumably in order to avoid accidental
 * allocation for random other mft records. Also, the sequence number for each
 * of the system files is always equal to their mft record number and it is
 * never modified.
 */
typedef enum {
        FILE_MFT       = 0,     /* Master file table (mft). Data attribute
                                   contains the entries and bitmap attribute
                                   records which ones are in use (bit==1). */
        FILE_MFTMirr   = 1,     /* Mft mirror: copy of first four mft records
                                   in data attribute. If cluster size > 4kiB,
                                   copy of first N mft records, with
                                        N = cluster_size / mft_record_size. */
        FILE_LogFile   = 2,     /* Journalling log in data attribute. */
        FILE_Volume    = 3,     /* Volume name attribute and volume information
                                   attribute (flags and ntfs version). Windows
                                   refers to this file as volume DASD (Direct
                                   Access Storage Device). */
        FILE_AttrDef   = 4,     /* Array of attribute definitions in data
                                   attribute. */
        FILE_root      = 5,     /* Root directory. */
        FILE_Bitmap    = 6,     /* Allocation bitmap of all clusters (lcns) in
                                   data attribute. */
        FILE_Boot      = 7,     /* Boot sector (always at cluster 0) in data
                                   attribute. */
        FILE_BadClus   = 8,     /* Contains all bad clusters in the non-resident
                                   data attribute. */
        FILE_Secure    = 9,     /* Shared security descriptors in data attribute
                                   and two indexes into the descriptors.
                                   Appeared in Windows 2000. Before that, this
                                   file was named $Quota but was unused. */
        FILE_UpCase    = 10,    /* Uppercase equivalents of all 65536 Unicode
                                   characters in data attribute. */
        FILE_Extend    = 11,    /* Directory containing other system files (eg.
                                   $ObjId, $Quota, $Reparse and $UsnJrnl). This
                                   is new to NTFS3.0. */
        FILE_reserved12 = 12,   /* Reserved for future use (records 12-15). */
        FILE_reserved13 = 13,
        FILE_reserved14 = 14,
        FILE_reserved15 = 15,
        FILE_first_user = 16,   /* First user file, used as test limit for
                                   whether to allow opening a file or not. */
} NTFS_SYSTEM_FILES;

/*
 * These are the so far known MFT_RECORD_* flags (16-bit) which contain
 * information about the mft record in which they are present.
 */
enum {
        MFT_RECORD_IN_USE       = const_cpu_to_le16(0x0001),
        MFT_RECORD_IS_DIRECTORY = const_cpu_to_le16(0x0002),
} __attribute__ ((__packed__));

typedef le16 MFT_RECORD_FLAGS;

/*
 * mft references (aka file references or file record segment references) are
 * used whenever a structure needs to refer to a record in the mft.
 *
 * A reference consists of a 48-bit index into the mft and a 16-bit sequence
 * number used to detect stale references.
 *
 * For error reporting purposes we treat the 48-bit index as a signed quantity.
 *
 * The sequence number is a circular counter (skipping 0) describing how many
 * times the referenced mft record has been (re)used. This has to match the
 * sequence number of the mft record being referenced, otherwise the reference
 * is considered stale and removed (FIXME: only ntfsck or the driver itself?).
 *
 * If the sequence number is zero it is assumed that no sequence number
 * consistency checking should be performed.
 *
 * FIXME: Since inodes are 32-bit as of now, the driver needs to always check
 * for high_part being 0 and if not either BUG(), cause a panic() or handle
 * the situation in some other way. This shouldn't be a problem as a volume has
 * to become HUGE in order to need more than 32-bits worth of mft records.
 * Assuming the standard mft record size of 1kb only the records (never mind
 * the non-resident attributes, etc.) would require 4Tb of space on their own
 * for the first 32 bits worth of records. This is only if some strange person
 * doesn't decide to foul play and make the mft sparse which would be a really
 * horrible thing to do as it would trash our current driver implementation. )-:
 * Do I hear screams "we want 64-bit inodes!" ?!? (-;
 *
 * FIXME: The mft zone is defined as the first 12% of the volume. This space is
 * reserved so that the mft can grow contiguously and hence doesn't become
 * fragmented. Volume free space includes the empty part of the mft zone and
 * when the volume's free 88% are used up, the mft zone is shrunk by a factor
 * of 2, thus making more space available for more files/data. This process is
 * repeated everytime there is no more free space except for the mft zone until
 * there really is no more free space.
 */

/*
 * Typedef the MFT_REF as a 64-bit value for easier handling.
 * Also define two unpacking macros to get to the reference (MREF) and
 * sequence number (MSEQNO) respectively.
 * The _LE versions are to be applied on little endian MFT_REFs.
 * Note: The _LE versions will return a CPU endian formatted value!
 */
typedef enum {
        MFT_REF_MASK_CPU        = 0x0000ffffffffffffULL,
        MFT_REF_MASK_LE         = const_cpu_to_le64(0x0000ffffffffffffULL),
} MFT_REF_CONSTS;

typedef u64 MFT_REF;
typedef le64 leMFT_REF;

#define MK_MREF(m, s)   ((MFT_REF)(((MFT_REF)(s) << 48) |               \
                                        ((MFT_REF)(m) & MFT_REF_MASK_CPU)))
#define MK_LE_MREF(m, s) cpu_to_le64(MK_MREF(m, s))

#define MREF(x)         ((unsigned long)((x) & MFT_REF_MASK_CPU))
#define MSEQNO(x)       ((u16)(((x) >> 48) & 0xffff))
#define MREF_LE(x)      ((unsigned long)(le64_to_cpu(x) & MFT_REF_MASK_CPU))
#define MSEQNO_LE(x)    ((u16)((le64_to_cpu(x) >> 48) & 0xffff))

#define IS_ERR_MREF(x)  (((x) & 0x0000800000000000ULL) ? 1 : 0)
#define ERR_MREF(x)     ((u64)((s64)(x)))
#define MREF_ERR(x)     ((int)((s64)(x)))

/*
 * The mft record header present at the beginning of every record in the mft.
 * This is followed by a sequence of variable length attribute records which
 * is terminated by an attribute of type AT_END which is a truncated attribute
 * in that it only consists of the attribute type code AT_END and none of the
 * other members of the attribute structure are present.
 */
typedef struct {
/*Ofs*/
/*  0   NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */
        NTFS_RECORD_TYPE magic; /* Usually the magic is "FILE". */
        le16 usa_ofs;           /* See NTFS_RECORD definition above. */
        le16 usa_count;         /* See NTFS_RECORD definition above. */

/*  8*/ le64 lsn;               /* $LogFile sequence number for this record.
                                   Changed every time the record is modified. */
/* 16*/ le16 sequence_number;   /* Number of times this mft record has been
                                   reused. (See description for MFT_REF
                                   above.) NOTE: The increment (skipping zero)
                                   is done when the file is deleted. NOTE: If
                                   this is zero it is left zero. */
/* 18*/ le16 link_count;        /* Number of hard links, i.e. the number of
                                   directory entries referencing this record.
                                   NOTE: Only used in mft base records.
                                   NOTE: When deleting a directory entry we
                                   check the link_count and if it is 1 we
                                   delete the file. Otherwise we delete the
                                   FILE_NAME_ATTR being referenced by the
                                   directory entry from the mft record and
                                   decrement the link_count.
                                   FIXME: Careful with Win32 + DOS names! */
/* 20*/ le16 attrs_offset;      /* Byte offset to the first attribute in this
                                   mft record from the start of the mft record.
                                   NOTE: Must be aligned to 8-byte boundary. */
/* 22*/ MFT_RECORD_FLAGS flags; /* Bit array of MFT_RECORD_FLAGS. When a file
                                   is deleted, the MFT_RECORD_IN_USE flag is
                                   set to zero. */
/* 24*/ le32 bytes_in_use;      /* Number of bytes used in this mft record.
                                   NOTE: Must be aligned to 8-byte boundary. */
/* 28*/ le32 bytes_allocated;   /* Number of bytes allocated for this mft
                                   record. This should be equal to the mft
                                   record size. */
/* 32*/ leMFT_REF base_mft_record;/* This is zero for base mft records.
                                   When it is not zero it is a mft reference
                                   pointing to the base mft record to which
                                   this record belongs (this is then used to
                                   locate the attribute list attribute present
                                   in the base record which describes this
                                   extension record and hence might need
                                   modification when the extension record
                                   itself is modified, also locating the
                                   attribute list also means finding the other
                                   potential extents, belonging to the non-base
                                   mft record). */
/* 40*/ le16 next_attr_instance;/* The instance number that will be assigned to
                                   the next attribute added to this mft record.
                                   NOTE: Incremented each time after it is used.
                                   NOTE: Every time the mft record is reused
                                   this number is set to zero.  NOTE: The first
                                   instance number is always 0. */
/* The below fields are specific to NTFS 3.1+ (Windows XP and above): */
/* 42*/ le16 reserved;          /* Reserved/alignment. */
/* 44*/ le32 mft_record_number; /* Number of this mft record. */
/* sizeof() = 48 bytes */
/*
 * When (re)using the mft record, we place the update sequence array at this
 * offset, i.e. before we start with the attributes.  This also makes sense,
 * otherwise we could run into problems with the update sequence array
 * containing in itself the last two bytes of a sector which would mean that
 * multi sector transfer protection wouldn't work.  As you can't protect data
 * by overwriting it since you then can't get it back...
 * When reading we obviously use the data from the ntfs record header.
 */
} __attribute__ ((__packed__)) MFT_RECORD;

/* This is the version without the NTFS 3.1+ specific fields. */
typedef struct {
/*Ofs*/
/*  0   NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */
        NTFS_RECORD_TYPE magic; /* Usually the magic is "FILE". */
        le16 usa_ofs;           /* See NTFS_RECORD definition above. */
        le16 usa_count;         /* See NTFS_RECORD definition above. */

/*  8*/ le64 lsn;               /* $LogFile sequence number for this record.
                                   Changed every time the record is modified. */
/* 16*/ le16 sequence_number;   /* Number of times this mft record has been
                                   reused. (See description for MFT_REF
                                   above.) NOTE: The increment (skipping zero)
                                   is done when the file is deleted. NOTE: If
                                   this is zero it is left zero. */
/* 18*/ le16 link_count;        /* Number of hard links, i.e. the number of
                                   directory entries referencing this record.
                                   NOTE: Only used in mft base records.
                                   NOTE: When deleting a directory entry we
                                   check the link_count and if it is 1 we
                                   delete the file. Otherwise we delete the
                                   FILE_NAME_ATTR being referenced by the
                                   directory entry from the mft record and
                                   decrement the link_count.
                                   FIXME: Careful with Win32 + DOS names! */
/* 20*/ le16 attrs_offset;      /* Byte offset to the first attribute in this
                                   mft record from the start of the mft record.
                                   NOTE: Must be aligned to 8-byte boundary. */
/* 22*/ MFT_RECORD_FLAGS flags; /* Bit array of MFT_RECORD_FLAGS. When a file
                                   is deleted, the MFT_RECORD_IN_USE flag is
                                   set to zero. */
/* 24*/ le32 bytes_in_use;      /* Number of bytes used in this mft record.
                                   NOTE: Must be aligned to 8-byte boundary. */
/* 28*/ le32 bytes_allocated;   /* Number of bytes allocated for this mft
                                   record. This should be equal to the mft
                                   record size. */
/* 32*/ leMFT_REF base_mft_record;/* This is zero for base mft records.
                                   When it is not zero it is a mft reference
                                   pointing to the base mft record to which
                                   this record belongs (this is then used to
                                   locate the attribute list attribute present
                                   in the base record which describes this
                                   extension record and hence might need
                                   modification when the extension record
                                   itself is modified, also locating the
                                   attribute list also means finding the other
                                   potential extents, belonging to the non-base
                                   mft record). */
/* 40*/ le16 next_attr_instance;/* The instance number that will be assigned to
                                   the next attribute added to this mft record.
                                   NOTE: Incremented each time after it is used.
                                   NOTE: Every time the mft record is reused
                                   this number is set to zero.  NOTE: The first
                                   instance number is always 0. */
/* sizeof() = 42 bytes */
/*
 * When (re)using the mft record, we place the update sequence array at this
 * offset, i.e. before we start with the attributes.  This also makes sense,
 * otherwise we could run into problems with the update sequence array
 * containing in itself the last two bytes of a sector which would mean that
 * multi sector transfer protection wouldn't work.  As you can't protect data
 * by overwriting it since you then can't get it back...
 * When reading we obviously use the data from the ntfs record header.
 */
} __attribute__ ((__packed__)) MFT_RECORD_OLD;

/*
 * System defined attributes (32-bit).  Each attribute type has a corresponding
 * attribute name (Unicode string of maximum 64 character length) as described
 * by the attribute definitions present in the data attribute of the $AttrDef
 * system file.  On NTFS 3.0 volumes the names are just as the types are named
 * in the below defines exchanging AT_ for the dollar sign ($).  If that is not
 * a revealing choice of symbol I do not know what is... (-;
 */
enum {
        AT_UNUSED                       = const_cpu_to_le32(         0),
        AT_STANDARD_INFORMATION         = const_cpu_to_le32(      0x10),
        AT_ATTRIBUTE_LIST               = const_cpu_to_le32(      0x20),
        AT_FILE_NAME                    = const_cpu_to_le32(      0x30),
        AT_OBJECT_ID                    = const_cpu_to_le32(      0x40),
        AT_SECURITY_DESCRIPTOR          = const_cpu_to_le32(      0x50),
        AT_VOLUME_NAME                  = const_cpu_to_le32(      0x60),
        AT_VOLUME_INFORMATION           = const_cpu_to_le32(      0x70),
        AT_DATA                         = const_cpu_to_le32(      0x80),
        AT_INDEX_ROOT                   = const_cpu_to_le32(      0x90),
        AT_INDEX_ALLOCATION             = const_cpu_to_le32(      0xa0),
        AT_BITMAP                       = const_cpu_to_le32(      0xb0),
        AT_REPARSE_POINT                = const_cpu_to_le32(      0xc0),
        AT_EA_INFORMATION               = const_cpu_to_le32(      0xd0),
        AT_EA                           = const_cpu_to_le32(      0xe0),
        AT_PROPERTY_SET                 = const_cpu_to_le32(      0xf0),
        AT_LOGGED_UTILITY_STREAM        = const_cpu_to_le32(     0x100),
        AT_FIRST_USER_DEFINED_ATTRIBUTE = const_cpu_to_le32(    0x1000),
        AT_END                          = const_cpu_to_le32(0xffffffff)
};

typedef le32 ATTR_TYPE;

/*
 * The collation rules for sorting views/indexes/etc (32-bit).
 *
 * COLLATION_BINARY - Collate by binary compare where the first byte is most
 *      significant.
 * COLLATION_UNICODE_STRING - Collate Unicode strings by comparing their binary
 *      Unicode values, except that when a character can be uppercased, the
 *      upper case value collates before the lower case one.
 * COLLATION_FILE_NAME - Collate file names as Unicode strings. The collation
 *      is done very much like COLLATION_UNICODE_STRING. In fact I have no idea
 *      what the difference is. Perhaps the difference is that file names
 *      would treat some special characters in an odd way (see
 *      unistr.c::ntfs_collate_names() and unistr.c::legal_ansi_char_array[]
 *      for what I mean but COLLATION_UNICODE_STRING would not give any special
 *      treatment to any characters at all, but this is speculation.
 * COLLATION_NTOFS_ULONG - Sorting is done according to ascending le32 key
 *      values. E.g. used for $SII index in FILE_Secure, which sorts by
 *      security_id (le32).
 * COLLATION_NTOFS_SID - Sorting is done according to ascending SID values.
 *      E.g. used for $O index in FILE_Extend/$Quota.
 * COLLATION_NTOFS_SECURITY_HASH - Sorting is done first by ascending hash
 *      values and second by ascending security_id values. E.g. used for $SDH
 *      index in FILE_Secure.
 * COLLATION_NTOFS_ULONGS - Sorting is done according to a sequence of ascending
 *      le32 key values. E.g. used for $O index in FILE_Extend/$ObjId, which
 *      sorts by object_id (16-byte), by splitting up the object_id in four
 *      le32 values and using them as individual keys. E.g. take the following
 *      two security_ids, stored as follows on disk:
 *              1st: a1 61 65 b7 65 7b d4 11 9e 3d 00 e0 81 10 42 59
 *              2nd: 38 14 37 d2 d2 f3 d4 11 a5 21 c8 6b 79 b1 97 45
 *      To compare them, they are split into four le32 values each, like so:
 *              1st: 0xb76561a1 0x11d47b65 0xe0003d9e 0x59421081
 *              2nd: 0xd2371438 0x11d4f3d2 0x6bc821a5 0x4597b179
 *      Now, it is apparent why the 2nd object_id collates after the 1st: the
 *      first le32 value of the 1st object_id is less than the first le32 of
 *      the 2nd object_id. If the first le32 values of both object_ids were
 *      equal then the second le32 values would be compared, etc.
 */
enum {
        COLLATION_BINARY                = const_cpu_to_le32(0x00),
        COLLATION_FILE_NAME             = const_cpu_to_le32(0x01),
        COLLATION_UNICODE_STRING        = const_cpu_to_le32(0x02),
        COLLATION_NTOFS_ULONG           = const_cpu_to_le32(0x10),
        COLLATION_NTOFS_SID             = const_cpu_to_le32(0x11),
        COLLATION_NTOFS_SECURITY_HASH   = const_cpu_to_le32(0x12),
        COLLATION_NTOFS_ULONGS          = const_cpu_to_le32(0x13),
};

typedef le32 COLLATION_RULE;

/*
 * The flags (32-bit) describing attribute properties in the attribute
 * definition structure.  FIXME: This information is based on Regis's
 * information and, according to him, it is not certain and probably
 * incomplete.  The INDEXABLE flag is fairly certainly correct as only the file
 * name attribute has this flag set and this is the only attribute indexed in
 * NT4.
 */
enum {
        ATTR_DEF_INDEXABLE      = const_cpu_to_le32(0x02), /* Attribute can be
                                        indexed. */
        ATTR_DEF_MULTIPLE       = const_cpu_to_le32(0x04), /* Attribute type
                                        can be present multiple times in the
                                        mft records of an inode. */
        ATTR_DEF_NOT_ZERO       = const_cpu_to_le32(0x08), /* Attribute value
                                        must contain at least one non-zero
                                        byte. */
        ATTR_DEF_INDEXED_UNIQUE = const_cpu_to_le32(0x10), /* Attribute must be
                                        indexed and the attribute value must be
                                        unique for the attribute type in all of
                                        the mft records of an inode. */
        ATTR_DEF_NAMED_UNIQUE   = const_cpu_to_le32(0x20), /* Attribute must be
                                        named and the name must be unique for
                                        the attribute type in all of the mft
                                        records of an inode. */
        ATTR_DEF_RESIDENT       = const_cpu_to_le32(0x40), /* Attribute must be
                                        resident. */
        ATTR_DEF_ALWAYS_LOG     = const_cpu_to_le32(0x80), /* Always log
                                        modifications to this attribute,
                                        regardless of whether it is resident or
                                        non-resident.  Without this, only log
                                        modifications if the attribute is
                                        resident. */
};

typedef le32 ATTR_DEF_FLAGS;

/*
 * The data attribute of FILE_AttrDef contains a sequence of attribute
 * definitions for the NTFS volume. With this, it is supposed to be safe for an
 * older NTFS driver to mount a volume containing a newer NTFS version without
 * damaging it (that's the theory. In practice it's: not damaging it too much).
 * Entries are sorted by attribute type. The flags describe whether the
 * attribute can be resident/non-resident and possibly other things, but the
 * actual bits are unknown.
 */
typedef struct {
/*hex ofs*/
/*  0*/ ntfschar name[0x40];            /* Unicode name of the attribute. Zero
                                           terminated. */
/* 80*/ ATTR_TYPE type;                 /* Type of the attribute. */
/* 84*/ le32 display_rule;              /* Default display rule.
                                           FIXME: What does it mean? (AIA) */
/* 88*/ COLLATION_RULE collation_rule;  /* Default collation rule. */
/* 8c*/ ATTR_DEF_FLAGS flags;           /* Flags describing the attribute. */
/* 90*/ sle64 min_size;                 /* Optional minimum attribute size. */
/* 98*/ sle64 max_size;                 /* Maximum size of attribute. */
/* sizeof() = 0xa0 or 160 bytes */
} __attribute__ ((__packed__)) ATTR_DEF;

/*
 * Attribute flags (16-bit).
 */
enum {
        ATTR_IS_COMPRESSED    = const_cpu_to_le16(0x0001),
        ATTR_COMPRESSION_MASK = const_cpu_to_le16(0x00ff), /* Compression method
                                                              mask.  Also, first
                                                              illegal value. */
        ATTR_IS_ENCRYPTED     = const_cpu_to_le16(0x4000),
        ATTR_IS_SPARSE        = const_cpu_to_le16(0x8000),
} __attribute__ ((__packed__));

typedef le16 ATTR_FLAGS;

/*
 * Attribute compression.
 *
 * Only the data attribute is ever compressed in the current ntfs driver in
 * Windows. Further, compression is only applied when the data attribute is
 * non-resident. Finally, to use compression, the maximum allowed cluster size
 * on a volume is 4kib.
 *
 * The compression method is based on independently compressing blocks of X
 * clusters, where X is determined from the compression_unit value found in the
 * non-resident attribute record header (more precisely: X = 2^compression_unit
 * clusters). On Windows NT/2k, X always is 16 clusters (compression_unit = 4).
 *
 * There are three different cases of how a compression block of X clusters
 * can be stored:
 *
 *   1) The data in the block is all zero (a sparse block):
 *        This is stored as a sparse block in the runlist, i.e. the runlist
 *        entry has length = X and lcn = -1. The mapping pairs array actually
 *        uses a delta_lcn value length of 0, i.e. delta_lcn is not present at
 *        all, which is then interpreted by the driver as lcn = -1.
 *        NOTE: Even uncompressed files can be sparse on NTFS 3.0 volumes, then
 *        the same principles apply as above, except that the length is not
 *        restricted to being any particular value.
 *
 *   2) The data in the block is not compressed:
 *        This happens when compression doesn't reduce the size of the block
 *        in clusters. I.e. if compression has a small effect so that the
 *        compressed data still occupies X clusters, then the uncompressed data
 *        is stored in the block.
 *        This case is recognised by the fact that the runlist entry has
 *        length = X and lcn >= 0. The mapping pairs array stores this as
 *        normal with a run length of X and some specific delta_lcn, i.e.
 *        delta_lcn has to be present.
 *
 *   3) The data in the block is compressed:
 *        The common case. This case is recognised by the fact that the run
 *        list entry has length L < X and lcn >= 0. The mapping pairs array
 *        stores this as normal with a run length of X and some specific
 *        delta_lcn, i.e. delta_lcn has to be present. This runlist entry is
 *        immediately followed by a sparse entry with length = X - L and
 *        lcn = -1. The latter entry is to make up the vcn counting to the
 *        full compression block size X.
 *
 * In fact, life is more complicated because adjacent entries of the same type
 * can be coalesced. This means that one has to keep track of the number of
 * clusters handled and work on a basis of X clusters at a time being one
 * block. An example: if length L > X this means that this particular runlist
 * entry contains a block of length X and part of one or more blocks of length
 * L - X. Another example: if length L < X, this does not necessarily mean that
 * the block is compressed as it might be that the lcn changes inside the block
 * and hence the following runlist entry describes the continuation of the
 * potentially compressed block. The block would be compressed if the
 * following runlist entry describes at least X - L sparse clusters, thus
 * making up the compression block length as described in point 3 above. (Of
 * course, there can be several runlist entries with small lengths so that the
 * sparse entry does not follow the first data containing entry with
 * length < X.)
 *
 * NOTE: At the end of the compressed attribute value, there most likely is not
 * just the right amount of data to make up a compression block, thus this data
 * is not even attempted to be compressed. It is just stored as is, unless
 * the number of clusters it occupies is reduced when compressed in which case
 * it is stored as a compressed compression block, complete with sparse
 * clusters at the end.
 */

/*
 * Flags of resident attributes (8-bit).
 */
enum {
        RESIDENT_ATTR_IS_INDEXED = 0x01, /* Attribute is referenced in an index
                                            (has implications for deleting and
                                            modifying the attribute). */
} __attribute__ ((__packed__));

typedef u8 RESIDENT_ATTR_FLAGS;

/*
 * Attribute record header. Always aligned to 8-byte boundary.
 */
typedef struct {
/*Ofs*/
/*  0*/ ATTR_TYPE type;         /* The (32-bit) type of the attribute. */
/*  4*/ le32 length;            /* Byte size of the resident part of the
                                   attribute (aligned to 8-byte boundary).
                                   Used to get to the next attribute. */
/*  8*/ u8 non_resident;        /* If 0, attribute is resident.
                                   If 1, attribute is non-resident. */
/*  9*/ u8 name_length;         /* Unicode character size of name of attribute.
                                   0 if unnamed. */
/* 10*/ le16 name_offset;       /* If name_length != 0, the byte offset to the
                                   beginning of the name from the attribute
                                   record. Note that the name is stored as a
                                   Unicode string. When creating, place offset
                                   just at the end of the record header. Then,
                                   follow with attribute value or mapping pairs
                                   array, resident and non-resident attributes
                                   respectively, aligning to an 8-byte
                                   boundary. */
/* 12*/ ATTR_FLAGS flags;       /* Flags describing the attribute. */
/* 14*/ le16 instance;          /* The instance of this attribute record. This
                                   number is unique within this mft record (see
                                   MFT_RECORD/next_attribute_instance notes in
                                   in mft.h for more details). */
/* 16*/ union {
                /* Resident attributes. */
                struct {
/* 16 */                le32 value_length;/* Byte size of attribute value. */
/* 20 */                le16 value_offset;/* Byte offset of the attribute
                                             value from the start of the
                                             attribute record. When creating,
                                             align to 8-byte boundary if we
                                             have a name present as this might
                                             not have a length of a multiple
                                             of 8-bytes. */
/* 22 */                RESIDENT_ATTR_FLAGS flags; /* See above. */
/* 23 */                s8 reserved;      /* Reserved/alignment to 8-byte
                                             boundary. */
                } __attribute__ ((__packed__)) resident;
                /* Non-resident attributes. */
                struct {
/* 16*/                 leVCN lowest_vcn;/* Lowest valid virtual cluster number
                                for this portion of the attribute value or
                                0 if this is the only extent (usually the
                                case). - Only when an attribute list is used
                                does lowest_vcn != 0 ever occur. */
/* 24*/                 leVCN highest_vcn;/* Highest valid vcn of this extent of
                                the attribute value. - Usually there is only one
                                portion, so this usually equals the attribute
                                value size in clusters minus 1. Can be -1 for
                                zero length files. Can be 0 for "single extent"
                                attributes. */
/* 32*/                 le16 mapping_pairs_offset; /* Byte offset from the
                                beginning of the structure to the mapping pairs
                                array which contains the mappings between the
                                vcns and the logical cluster numbers (lcns).
                                When creating, place this at the end of this
                                record header aligned to 8-byte boundary. */
/* 34*/                 u8 compression_unit; /* The compression unit expressed
                                as the log to the base 2 of the number of
                                clusters in a compression unit.  0 means not
                                compressed.  (This effectively limits the
                                compression unit size to be a power of two
                                clusters.)  WinNT4 only uses a value of 4.
                                Sparse files also have this set to 4. */
/* 35*/                 u8 reserved[5];         /* Align to 8-byte boundary. */
/* The sizes below are only used when lowest_vcn is zero, as otherwise it would
   be difficult to keep them up-to-date.*/
/* 40*/                 sle64 allocated_size;   /* Byte size of disk space
                                allocated to hold the attribute value. Always
                                is a multiple of the cluster size. When a file
                                is compressed, this field is a multiple of the
                                compression block size (2^compression_unit) and
                                it represents the logically allocated space
                                rather than the actual on disk usage. For this
                                use the compressed_size (see below). */
/* 48*/                 sle64 data_size;        /* Byte size of the attribute
                                value. Can be larger than allocated_size if
                                attribute value is compressed or sparse. */
/* 56*/                 sle64 initialized_size; /* Byte size of initialized
                                portion of the attribute value. Usually equals
                                data_size. */
/* sizeof(uncompressed attr) = 64*/
/* 64*/                 sle64 compressed_size;  /* Byte size of the attribute
                                value after compression.  Only present when
                                compressed or sparse.  Always is a multiple of
                                the cluster size.  Represents the actual amount
                                of disk space being used on the disk. */
/* sizeof(compressed attr) = 72*/
                } __attribute__ ((__packed__)) non_resident;
        } __attribute__ ((__packed__)) data;
} __attribute__ ((__packed__)) ATTR_RECORD;

typedef ATTR_RECORD ATTR_REC;

/*
 * File attribute flags (32-bit).
 */
enum {
        /*
         * The following flags are only present in the STANDARD_INFORMATION
         * attribute (in the field file_attributes).
         */
        FILE_ATTR_READONLY              = const_cpu_to_le32(0x00000001),
        FILE_ATTR_HIDDEN                = const_cpu_to_le32(0x00000002),
        FILE_ATTR_SYSTEM                = const_cpu_to_le32(0x00000004),
        /* Old DOS volid. Unused in NT. = const_cpu_to_le32(0x00000008), */

        FILE_ATTR_DIRECTORY             = const_cpu_to_le32(0x00000010),
        /* Note, FILE_ATTR_DIRECTORY is not considered valid in NT.  It is
           reserved for the DOS SUBDIRECTORY flag. */
        FILE_ATTR_ARCHIVE               = const_cpu_to_le32(0x00000020),
        FILE_ATTR_DEVICE                = const_cpu_to_le32(0x00000040),
        FILE_ATTR_NORMAL                = const_cpu_to_le32(0x00000080),

        FILE_ATTR_TEMPORARY             = const_cpu_to_le32(0x00000100),
        FILE_ATTR_SPARSE_FILE           = const_cpu_to_le32(0x00000200),
        FILE_ATTR_REPARSE_POINT         = const_cpu_to_le32(0x00000400),
        FILE_ATTR_COMPRESSED            = const_cpu_to_le32(0x00000800),

        FILE_ATTR_OFFLINE               = const_cpu_to_le32(0x00001000),
        FILE_ATTR_NOT_CONTENT_INDEXED   = const_cpu_to_le32(0x00002000),
        FILE_ATTR_ENCRYPTED             = const_cpu_to_le32(0x00004000),

        FILE_ATTR_VALID_FLAGS           = const_cpu_to_le32(0x00007fb7),
        /* Note, FILE_ATTR_VALID_FLAGS masks out the old DOS VolId and the
           FILE_ATTR_DEVICE and preserves everything else.  This mask is used
           to obtain all flags that are valid for reading. */
        FILE_ATTR_VALID_SET_FLAGS       = const_cpu_to_le32(0x000031a7),
        /* Note, FILE_ATTR_VALID_SET_FLAGS masks out the old DOS VolId, the
           F_A_DEVICE, F_A_DIRECTORY, F_A_SPARSE_FILE, F_A_REPARSE_POINT,
           F_A_COMPRESSED, and F_A_ENCRYPTED and preserves the rest.  This mask
           is used to to obtain all flags that are valid for setting. */

        /*
         * The following flags are only present in the FILE_NAME attribute (in
         * the field file_attributes).
         */
        FILE_ATTR_DUP_FILE_NAME_INDEX_PRESENT   = const_cpu_to_le32(0x10000000),
        /* Note, this is a copy of the corresponding bit from the mft record,
           telling us whether this is a directory or not, i.e. whether it has
           an index root attribute or not. */
        FILE_ATTR_DUP_VIEW_INDEX_PRESENT        = const_cpu_to_le32(0x20000000),
        /* Note, this is a copy of the corresponding bit from the mft record,
           telling us whether this file has a view index present (eg. object id
           index, quota index, one of the security indexes or the encrypting
           filesystem related indexes). */
};

typedef le32 FILE_ATTR_FLAGS;

/*
 * NOTE on times in NTFS: All times are in MS standard time format, i.e. they
 * are the number of 100-nanosecond intervals since 1st January 1601, 00:00:00
 * universal coordinated time (UTC). (In Linux time starts 1st January 1970,
 * 00:00:00 UTC and is stored as the number of 1-second intervals since then.)
 */

/*
 * Attribute: Standard information (0x10).
 *
 * NOTE: Always resident.
 * NOTE: Present in all base file records on a volume.
 * NOTE: There is conflicting information about the meaning of each of the time
 *       fields but the meaning as defined below has been verified to be
 *       correct by practical experimentation on Windows NT4 SP6a and is hence
 *       assumed to be the one and only correct interpretation.
 */
typedef struct {
/*Ofs*/
/*  0*/ sle64 creation_time;            /* Time file was created. Updated when
                                           a filename is changed(?). */
/*  8*/ sle64 last_data_change_time;    /* Time the data attribute was last
                                           modified. */
/* 16*/ sle64 last_mft_change_time;     /* Time this mft record was last
                                           modified. */
/* 24*/ sle64 last_access_time;         /* Approximate time when the file was
                                           last accessed (obviously this is not
                                           updated on read-only volumes). In
                                           Windows this is only updated when
                                           accessed if some time delta has
                                           passed since the last update. Also,
                                           last access times updates can be
                                           disabled altogether for speed. */
/* 32*/ FILE_ATTR_FLAGS file_attributes; /* Flags describing the file. */
/* 36*/ union {
        /* NTFS 1.2 */
                struct {
                /* 36*/ u8 reserved12[12];      /* Reserved/alignment to 8-byte
                                                   boundary. */
                } __attribute__ ((__packed__)) v1;
        /* sizeof() = 48 bytes */
        /* NTFS 3.x */
                struct {
/*
 * If a volume has been upgraded from a previous NTFS version, then these
 * fields are present only if the file has been accessed since the upgrade.
 * Recognize the difference by comparing the length of the resident attribute
 * value. If it is 48, then the following fields are missing. If it is 72 then
 * the fields are present. Maybe just check like this:
 *      if (resident.ValueLength < sizeof(STANDARD_INFORMATION)) {
 *              Assume NTFS 1.2- format.
 *              If (volume version is 3.x)
 *                      Upgrade attribute to NTFS 3.x format.
 *              else
 *                      Use NTFS 1.2- format for access.
 *      } else
 *              Use NTFS 3.x format for access.
 * Only problem is that it might be legal to set the length of the value to
 * arbitrarily large values thus spoiling this check. - But chkdsk probably
 * views that as a corruption, assuming that it behaves like this for all
 * attributes.
 */
                /* 36*/ le32 maximum_versions;  /* Maximum allowed versions for
                                file. Zero if version numbering is disabled. */
                /* 40*/ le32 version_number;    /* This file's version (if any).
                                Set to zero if maximum_versions is zero. */
                /* 44*/ le32 class_id;          /* Class id from bidirectional
                                class id index (?). */
                /* 48*/ le32 owner_id;          /* Owner_id of the user owning
                                the file. Translate via $Q index in FILE_Extend
                                /$Quota to the quota control entry for the user
                                owning the file. Zero if quotas are disabled. */
                /* 52*/ le32 security_id;       /* Security_id for the file.
                                Translate via $SII index and $SDS data stream
                                in FILE_Secure to the security descriptor. */
                /* 56*/ le64 quota_charged;     /* Byte size of the charge to
                                the quota for all streams of the file. Note: Is
                                zero if quotas are disabled. */
                /* 64*/ le64 usn;               /* Last update sequence number
                                of the file. This is a direct index into the
                                change (aka usn) journal file. It is zero if
                                the usn journal is disabled.
                                NOTE: To disable the journal need to delete
                                the journal file itself and to then walk the
                                whole mft and set all Usn entries in all mft
                                records to zero! (This can take a while!)
                                The journal is FILE_Extend/$UsnJrnl. Win2k
                                will recreate the journal and initiate
                                logging if necessary when mounting the
                                partition. This, in contrast to disabling the
                                journal is a very fast process, so the user
                                won't even notice it. */
                } __attribute__ ((__packed__)) v3;
        /* sizeof() = 72 bytes (NTFS 3.x) */
        } __attribute__ ((__packed__)) ver;
} __attribute__ ((__packed__)) STANDARD_INFORMATION;

/*
 * Attribute: Attribute list (0x20).
 *
 * - Can be either resident or non-resident.
 * - Value consists of a sequence of variable length, 8-byte aligned,
 * ATTR_LIST_ENTRY records.
 * - The list is not terminated by anything at all! The only way to know when
 * the end is reached is to keep track of the current offset and compare it to
 * the attribute value size.
 * - The attribute list attribute contains one entry for each attribute of
 * the file in which the list is located, except for the list attribute
 * itself. The list is sorted: first by attribute type, second by attribute
 * name (if present), third by instance number. The extents of one
 * non-resident attribute (if present) immediately follow after the initial
 * extent. They are ordered by lowest_vcn and have their instace set to zero.
 * It is not allowed to have two attributes with all sorting keys equal.
 * - Further restrictions:
 *      - If not resident, the vcn to lcn mapping array has to fit inside the
 *        base mft record.
 *      - The attribute list attribute value has a maximum size of 256kb. This
 *        is imposed by the Windows cache manager.
 * - Attribute lists are only used when the attributes of mft record do not
 * fit inside the mft record despite all attributes (that can be made
 * non-resident) having been made non-resident. This can happen e.g. when:
 *      - File has a large number of hard links (lots of file name
 *        attributes present).
 *      - The mapping pairs array of some non-resident attribute becomes so
 *        large due to fragmentation that it overflows the mft record.
 *      - The security descriptor is very complex (not applicable to
 *        NTFS 3.0 volumes).
 *      - There are many named streams.
 */
typedef struct {
/*Ofs*/
/*  0*/ ATTR_TYPE type;         /* Type of referenced attribute. */
/*  4*/ le16 length;            /* Byte size of this entry (8-byte aligned). */
/*  6*/ u8 name_length;         /* Size in Unicode chars of the name of the
                                   attribute or 0 if unnamed. */
/*  7*/ u8 name_offset;         /* Byte offset to beginning of attribute name
                                   (always set this to where the name would
                                   start even if unnamed). */
/*  8*/ leVCN lowest_vcn;       /* Lowest virtual cluster number of this portion
                                   of the attribute value. This is usually 0. It
                                   is non-zero for the case where one attribute
                                   does not fit into one mft record and thus
                                   several mft records are allocated to hold
                                   this attribute. In the latter case, each mft
                                   record holds one extent of the attribute and
                                   there is one attribute list entry for each
                                   extent. NOTE: This is DEFINITELY a signed
                                   value! The windows driver uses cmp, followed
                                   by jg when comparing this, thus it treats it
                                   as signed. */
/* 16*/ leMFT_REF mft_reference;/* The reference of the mft record holding
                                   the ATTR_RECORD for this portion of the
                                   attribute value. */
/* 24*/ le16 instance;          /* If lowest_vcn = 0, the instance of the
                                   attribute being referenced; otherwise 0. */
/* 26*/ ntfschar name[0];       /* Use when creating only. When reading use
                                   name_offset to determine the location of the
                                   name. */
/* sizeof() = 26 + (attribute_name_length * 2) bytes */
} __attribute__ ((__packed__)) ATTR_LIST_ENTRY;

/*
 * The maximum allowed length for a file name.
 */
#define MAXIMUM_FILE_NAME_LENGTH        255

/*
 * Possible namespaces for filenames in ntfs (8-bit).
 */
enum {
        FILE_NAME_POSIX         = 0x00,
        /* This is the largest namespace. It is case sensitive and allows all
           Unicode characters except for: '\0' and '/'.  Beware that in
           WinNT/2k files which eg have the same name except for their case
           will not be distinguished by the standard utilities and thus a "del
           filename" will delete both "filename" and "fileName" without
           warning. */
        FILE_NAME_WIN32         = 0x01,
        /* The standard WinNT/2k NTFS long filenames. Case insensitive.  All
           Unicode chars except: '\0', '"', '*', '/', ':', '<', '>', '?', '\',
           and '|'.  Further, names cannot end with a '.' or a space. */
        FILE_NAME_DOS           = 0x02,
        /* The standard DOS filenames (8.3 format). Uppercase only.  All 8-bit
           characters greater space, except: '"', '*', '+', ',', '/', ':', ';',
           '<', '=', '>', '?', and '\'. */
        FILE_NAME_WIN32_AND_DOS = 0x03,
        /* 3 means that both the Win32 and the DOS filenames are identical and
           hence have been saved in this single filename record. */
} __attribute__ ((__packed__));

typedef u8 FILE_NAME_TYPE_FLAGS;

/*
 * Attribute: Filename (0x30).
 *
 * NOTE: Always resident.
 * NOTE: All fields, except the parent_directory, are only updated when the
 *       filename is changed. Until then, they just become out of sync with
 *       reality and the more up to date values are present in the standard
 *       information attribute.
 * NOTE: There is conflicting information about the meaning of each of the time
 *       fields but the meaning as defined below has been verified to be
 *       correct by practical experimentation on Windows NT4 SP6a and is hence
 *       assumed to be the one and only correct interpretation.
 */
typedef struct {
/*hex ofs*/
/*  0*/ leMFT_REF parent_directory;     /* Directory this filename is
                                           referenced from. */
/*  8*/ sle64 creation_time;            /* Time file was created. */
/* 10*/ sle64 last_data_change_time;    /* Time the data attribute was last
                                           modified. */
/* 18*/ sle64 last_mft_change_time;     /* Time this mft record was last
                                           modified. */
/* 20*/ sle64 last_access_time;         /* Time this mft record was last
                                           accessed. */
/* 28*/ sle64 allocated_size;           /* Byte size of allocated space for the
                                           data attribute. NOTE: Is a multiple
                                           of the cluster size. */
/* 30*/ sle64 data_size;                /* Byte size of actual data in data
                                           attribute. */
/* 38*/ FILE_ATTR_FLAGS file_attributes;        /* Flags describing the file. */
/* 3c*/ union {
        /* 3c*/ struct {
                /* 3c*/ le16 packed_ea_size;    /* Size of the buffer needed to
                                                   pack the extended attributes
                                                   (EAs), if such are present.*/
                /* 3e*/ le16 reserved;          /* Reserved for alignment. */
                } __attribute__ ((__packed__)) ea;
        /* 3c*/ struct {
                /* 3c*/ le32 reparse_point_tag; /* Type of reparse point,
                                                   present only in reparse
                                                   points and only if there are
                                                   no EAs. */
                } __attribute__ ((__packed__)) rp;
        } __attribute__ ((__packed__)) type;
/* 40*/ u8 file_name_length;                    /* Length of file name in
                                                   (Unicode) characters. */
/* 41*/ FILE_NAME_TYPE_FLAGS file_name_type;    /* Namespace of the file name.*/
/* 42*/ ntfschar file_name[0];                  /* File name in Unicode. */
} __attribute__ ((__packed__)) FILE_NAME_ATTR;

/*
 * GUID structures store globally unique identifiers (GUID). A GUID is a
 * 128-bit value consisting of one group of eight hexadecimal digits, followed
 * by three groups of four hexadecimal digits each, followed by one group of
 * twelve hexadecimal digits. GUIDs are Microsoft's implementation of the
 * distributed computing environment (DCE) universally unique identifier (UUID).
 * Example of a GUID:
 *      1F010768-5A73-BC91-0010A52216A7
 */
typedef struct {
        le32 data1;     /* The first eight hexadecimal digits of the GUID. */
        le16 data2;     /* The first group of four hexadecimal digits. */
        le16 data3;     /* The second group of four hexadecimal digits. */
        u8 data4[8];    /* The first two bytes are the third group of four
                           hexadecimal digits. The remaining six bytes are the
                           final 12 hexadecimal digits. */
} __attribute__ ((__packed__)) GUID;

/*
 * FILE_Extend/$ObjId contains an index named $O. This index contains all
 * object_ids present on the volume as the index keys and the corresponding
 * mft_record numbers as the index entry data parts. The data part (defined
 * below) also contains three other object_ids:
 *      birth_volume_id - object_id of FILE_Volume on which the file was first
 *                        created. Optional (i.e. can be zero).
 *      birth_object_id - object_id of file when it was first created. Usually
 *                        equals the object_id. Optional (i.e. can be zero).
 *      domain_id       - Reserved (always zero).
 */
typedef struct {
        leMFT_REF mft_reference;/* Mft record containing the object_id in
                                   the index entry key. */
        union {
                struct {
                        GUID birth_volume_id;
                        GUID birth_object_id;
                        GUID domain_id;
                } __attribute__ ((__packed__)) origin;
                u8 extended_info[48];
        } __attribute__ ((__packed__)) opt;
} __attribute__ ((__packed__)) OBJ_ID_INDEX_DATA;

/*
 * Attribute: Object id (NTFS 3.0+) (0x40).
 *
 * NOTE: Always resident.
 */
typedef struct {
        GUID object_id;                         /* Unique id assigned to the
                                                   file.*/
        /* The following fields are optional. The attribute value size is 16
           bytes, i.e. sizeof(GUID), if these are not present at all. Note,
           the entries can be present but one or more (or all) can be zero
           meaning that that particular value(s) is(are) not defined. */
        union {
                struct {
                        GUID birth_volume_id;   /* Unique id of volume on which
                                                   the file was first created.*/
                        GUID birth_object_id;   /* Unique id of file when it was
                                                   first created. */
                        GUID domain_id;         /* Reserved, zero. */
                } __attribute__ ((__packed__)) origin;
                u8 extended_info[48];
        } __attribute__ ((__packed__)) opt;
} __attribute__ ((__packed__)) OBJECT_ID_ATTR;

/*
 * The pre-defined IDENTIFIER_AUTHORITIES used as SID_IDENTIFIER_AUTHORITY in
 * the SID structure (see below).
 */
//typedef enum {                                        /* SID string prefix. */
//      SECURITY_NULL_SID_AUTHORITY     = {0, 0, 0, 0, 0, 0},   /* S-1-0 */
//      SECURITY_WORLD_SID_AUTHORITY    = {0, 0, 0, 0, 0, 1},   /* S-1-1 */
//      SECURITY_LOCAL_SID_AUTHORITY    = {0, 0, 0, 0, 0, 2},   /* S-1-2 */
//      SECURITY_CREATOR_SID_AUTHORITY  = {0, 0, 0, 0, 0, 3},   /* S-1-3 */
//      SECURITY_NON_UNIQUE_AUTHORITY   = {0, 0, 0, 0, 0, 4},   /* S-1-4 */
//      SECURITY_NT_SID_AUTHORITY       = {0, 0, 0, 0, 0, 5},   /* S-1-5 */
//} IDENTIFIER_AUTHORITIES;

/*
 * These relative identifiers (RIDs) are used with the above identifier
 * authorities to make up universal well-known SIDs.
 *
 * Note: The relative identifier (RID) refers to the portion of a SID, which
 * identifies a user or group in relation to the authority that issued the SID.
 * For example, the universal well-known SID Creator Owner ID (S-1-3-0) is
 * made up of the identifier authority SECURITY_CREATOR_SID_AUTHORITY (3) and
 * the relative identifier SECURITY_CREATOR_OWNER_RID (0).
 */
typedef enum {                                  /* Identifier authority. */
        SECURITY_NULL_RID                 = 0,  /* S-1-0 */
        SECURITY_WORLD_RID                = 0,  /* S-1-1 */
        SECURITY_LOCAL_RID                = 0,  /* S-1-2 */

        SECURITY_CREATOR_OWNER_RID        = 0,  /* S-1-3 */
        SECURITY_CREATOR_GROUP_RID        = 1,  /* S-1-3 */

        SECURITY_CREATOR_OWNER_SERVER_RID = 2,  /* S-1-3 */
        SECURITY_CREATOR_GROUP_SERVER_RID = 3,  /* S-1-3 */

        SECURITY_DIALUP_RID               = 1,
        SECURITY_NETWORK_RID              = 2,
        SECURITY_BATCH_RID                = 3,
        SECURITY_INTERACTIVE_RID          = 4,
        SECURITY_SERVICE_RID              = 6,
        SECURITY_ANONYMOUS_LOGON_RID      = 7,
        SECURITY_PROXY_RID                = 8,
        SECURITY_ENTERPRISE_CONTROLLERS_RID=9,
        SECURITY_SERVER_LOGON_RID         = 9,
        SECURITY_PRINCIPAL_SELF_RID       = 0xa,
        SECURITY_AUTHENTICATED_USER_RID   = 0xb,
        SECURITY_RESTRICTED_CODE_RID      = 0xc,
        SECURITY_TERMINAL_SERVER_RID      = 0xd,

        SECURITY_LOGON_IDS_RID            = 5,
        SECURITY_LOGON_IDS_RID_COUNT      = 3,

        SECURITY_LOCAL_SYSTEM_RID         = 0x12,

        SECURITY_NT_NON_UNIQUE            = 0x15,

        SECURITY_BUILTIN_DOMAIN_RID       = 0x20,

        /*
         * Well-known domain relative sub-authority values (RIDs).
         */

        /* Users. */
        DOMAIN_USER_RID_ADMIN             = 0x1f4,
        DOMAIN_USER_RID_GUEST             = 0x1f5,
        DOMAIN_USER_RID_KRBTGT            = 0x1f6,

        /* Groups. */
        DOMAIN_GROUP_RID_ADMINS           = 0x200,
        DOMAIN_GROUP_RID_USERS            = 0x201,
        DOMAIN_GROUP_RID_GUESTS           = 0x202,
        DOMAIN_GROUP_RID_COMPUTERS        = 0x203,
        DOMAIN_GROUP_RID_CONTROLLERS      = 0x204,
        DOMAIN_GROUP_RID_CERT_ADMINS      = 0x205,
        DOMAIN_GROUP_RID_SCHEMA_ADMINS    = 0x206,
        DOMAIN_GROUP_RID_ENTERPRISE_ADMINS= 0x207,
        DOMAIN_GROUP_RID_POLICY_ADMINS    = 0x208,

        /* Aliases. */
        DOMAIN_ALIAS_RID_ADMINS           = 0x220,
        DOMAIN_ALIAS_RID_USERS            = 0x221,
        DOMAIN_ALIAS_RID_GUESTS           = 0x222,
        DOMAIN_ALIAS_RID_POWER_USERS      = 0x223,

        DOMAIN_ALIAS_RID_ACCOUNT_OPS      = 0x224,
        DOMAIN_ALIAS_RID_SYSTEM_OPS       = 0x225,
        DOMAIN_ALIAS_RID_PRINT_OPS        = 0x226,
        DOMAIN_ALIAS_RID_BACKUP_OPS       = 0x227,

        DOMAIN_ALIAS_RID_REPLICATOR       = 0x228,
        DOMAIN_ALIAS_RID_RAS_SERVERS      = 0x229,
        DOMAIN_ALIAS_RID_PREW2KCOMPACCESS = 0x22a,
} RELATIVE_IDENTIFIERS;

/*
 * The universal well-known SIDs:
 *
 *      NULL_SID                        S-1-0-0
 *      WORLD_SID                       S-1-1-0
 *      LOCAL_SID                       S-1-2-0
 *      CREATOR_OWNER_SID               S-1-3-0
 *      CREATOR_GROUP_SID               S-1-3-1
 *      CREATOR_OWNER_SERVER_SID        S-1-3-2
 *      CREATOR_GROUP_SERVER_SID        S-1-3-3
 *
 *      (Non-unique IDs)                S-1-4
 *
 * NT well-known SIDs:
 *
 *      NT_AUTHORITY_SID        S-1-5
 *      DIALUP_SID              S-1-5-1
 *
 *      NETWORD_SID             S-1-5-2
 *      BATCH_SID               S-1-5-3
 *      INTERACTIVE_SID         S-1-5-4
 *      SERVICE_SID             S-1-5-6
 *      ANONYMOUS_LOGON_SID     S-1-5-7         (aka null logon session)
 *      PROXY_SID               S-1-5-8
 *      SERVER_LOGON_SID        S-1-5-9         (aka domain controller account)
 *      SELF_SID                S-1-5-10        (self RID)
 *      AUTHENTICATED_USER_SID  S-1-5-11
 *      RESTRICTED_CODE_SID     S-1-5-12        (running restricted code)
 *      TERMINAL_SERVER_SID     S-1-5-13        (running on terminal server)
 *
 *      (Logon IDs)             S-1-5-5-X-Y
 *
 *      (NT non-unique IDs)     S-1-5-0x15-...
 *
 *      (Built-in domain)       S-1-5-0x20
 */

/*
 * The SID_IDENTIFIER_AUTHORITY is a 48-bit value used in the SID structure.
 *
 * NOTE: This is stored as a big endian number, hence the high_part comes
 * before the low_part.
 */
typedef union {
        struct {
                u16 high_part;  /* High 16-bits. */
                u32 low_part;   /* Low 32-bits. */
        } __attribute__ ((__packed__)) parts;
        u8 value[6];            /* Value as individual bytes. */
} __attribute__ ((__packed__)) SID_IDENTIFIER_AUTHORITY;

/*
 * The SID structure is a variable-length structure used to uniquely identify
 * users or groups. SID stands for security identifier.
 *
 * The standard textual representation of the SID is of the form:
 *      S-R-I-S-S...
 * Where:
 *    - The first "S" is the literal character 'S' identifying the following
 *      digits as a SID.
 *    - R is the revision level of the SID expressed as a sequence of digits
 *      either in decimal or hexadecimal (if the later, prefixed by "0x").
 *    - I is the 48-bit identifier_authority, expressed as digits as R above.
 *    - S... is one or more sub_authority values, expressed as digits as above.
 *
 * Example SID; the domain-relative SID of the local Administrators group on
 * Windows NT/2k:
 *      S-1-5-32-544
 * This translates to a SID with:
 *      revision = 1,
 *      sub_authority_count = 2,
 *      identifier_authority = {0,0,0,0,0,5},   // SECURITY_NT_AUTHORITY
 *      sub_authority[0] = 32,                  // SECURITY_BUILTIN_DOMAIN_RID
 *      sub_authority[1] = 544                  // DOMAIN_ALIAS_RID_ADMINS
 */
typedef struct {
        u8 revision;
        u8 sub_authority_count;
        SID_IDENTIFIER_AUTHORITY identifier_authority;
        le32 sub_authority[1];          /* At least one sub_authority. */
} __attribute__ ((__packed__)) SID;

/*
 * Current constants for SIDs.
 */
typedef enum {
        SID_REVISION                    =  1,   /* Current revision level. */
        SID_MAX_SUB_AUTHORITIES         = 15,   /* Maximum number of those. */
        SID_RECOMMENDED_SUB_AUTHORITIES =  1,   /* Will change to around 6 in
                                                   a future revision. */
} SID_CONSTANTS;

/*
 * The predefined ACE types (8-bit, see below).
 */
enum {
        ACCESS_MIN_MS_ACE_TYPE          = 0,
        ACCESS_ALLOWED_ACE_TYPE         = 0,
        ACCESS_DENIED_ACE_TYPE          = 1,
        SYSTEM_AUDIT_ACE_TYPE           = 2,
        SYSTEM_ALARM_ACE_TYPE           = 3, /* Not implemented as of Win2k. */
        ACCESS_MAX_MS_V2_ACE_TYPE       = 3,

        ACCESS_ALLOWED_COMPOUND_ACE_TYPE= 4,
        ACCESS_MAX_MS_V3_ACE_TYPE       = 4,

        /* The following are Win2k only. */
        ACCESS_MIN_MS_OBJECT_ACE_TYPE   = 5,
        ACCESS_ALLOWED_OBJECT_ACE_TYPE  = 5,
        ACCESS_DENIED_OBJECT_ACE_TYPE   = 6,
        SYSTEM_AUDIT_OBJECT_ACE_TYPE    = 7,
        SYSTEM_ALARM_OBJECT_ACE_TYPE    = 8,
        ACCESS_MAX_MS_OBJECT_ACE_TYPE   = 8,

        ACCESS_MAX_MS_V4_ACE_TYPE       = 8,

        /* This one is for WinNT/2k. */
        ACCESS_MAX_MS_ACE_TYPE          = 8,
} __attribute__ ((__packed__));

typedef u8 ACE_TYPES;

/*
 * The ACE flags (8-bit) for audit and inheritance (see below).
 *
 * SUCCESSFUL_ACCESS_ACE_FLAG is only used with system audit and alarm ACE
 * types to indicate that a message is generated (in Windows!) for successful
 * accesses.
 *
 * FAILED_ACCESS_ACE_FLAG is only used with system audit and alarm ACE types
 * to indicate that a message is generated (in Windows!) for failed accesses.
 */
enum {
        /* The inheritance flags. */
        OBJECT_INHERIT_ACE              = 0x01,
        CONTAINER_INHERIT_ACE           = 0x02,
        NO_PROPAGATE_INHERIT_ACE        = 0x04,
        INHERIT_ONLY_ACE                = 0x08,
        INHERITED_ACE                   = 0x10, /* Win2k only. */
        VALID_INHERIT_FLAGS             = 0x1f,

        /* The audit flags. */
        SUCCESSFUL_ACCESS_ACE_FLAG      = 0x40,
        FAILED_ACCESS_ACE_FLAG          = 0x80,
} __attribute__ ((__packed__));

typedef u8 ACE_FLAGS;

/*
 * An ACE is an access-control entry in an access-control list (ACL).
 * An ACE defines access to an object for a specific user or group or defines
 * the types of access that generate system-administration messages or alarms
 * for a specific user or group. The user or group is identified by a security
 * identifier (SID).
 *
 * Each ACE starts with an ACE_HEADER structure (aligned on 4-byte boundary),
 * which specifies the type and size of the ACE. The format of the subsequent
 * data depends on the ACE type.
 */
typedef struct {
/*Ofs*/
/*  0*/ ACE_TYPES type;         /* Type of the ACE. */
/*  1*/ ACE_FLAGS flags;        /* Flags describing the ACE. */
/*  2*/ le16 size;              /* Size in bytes of the ACE. */
} __attribute__ ((__packed__)) ACE_HEADER;

/*
 * The access mask (32-bit). Defines the access rights.
 *
 * The specific rights (bits 0 to 15).  These depend on the type of the object
 * being secured by the ACE.
 */
enum {
        /* Specific rights for files and directories are as follows: */

        /* Right to read data from the file. (FILE) */
        FILE_READ_DATA                  = const_cpu_to_le32(0x00000001),
        /* Right to list contents of a directory. (DIRECTORY) */
        FILE_LIST_DIRECTORY             = const_cpu_to_le32(0x00000001),

        /* Right to write data to the file. (FILE) */
        FILE_WRITE_DATA                 = const_cpu_to_le32(0x00000002),
        /* Right to create a file in the directory. (DIRECTORY) */
        FILE_ADD_FILE                   = const_cpu_to_le32(0x00000002),

        /* Right to append data to the file. (FILE) */
        FILE_APPEND_DATA                = const_cpu_to_le32(0x00000004),
        /* Right to create a subdirectory. (DIRECTORY) */
        FILE_ADD_SUBDIRECTORY           = const_cpu_to_le32(0x00000004),

        /* Right to read extended attributes. (FILE/DIRECTORY) */
        FILE_READ_EA                    = const_cpu_to_le32(0x00000008),

        /* Right to write extended attributes. (FILE/DIRECTORY) */
        FILE_WRITE_EA                   = const_cpu_to_le32(0x00000010),

        /* Right to execute a file. (FILE) */
        FILE_EXECUTE                    = const_cpu_to_le32(0x00000020),
        /* Right to traverse the directory. (DIRECTORY) */
        FILE_TRAVERSE                   = const_cpu_to_le32(0x00000020),

        /*
         * Right to delete a directory and all the files it contains (its
         * children), even if the files are read-only. (DIRECTORY)
         */
        FILE_DELETE_CHILD               = const_cpu_to_le32(0x00000040),

        /* Right to read file attributes. (FILE/DIRECTORY) */
        FILE_READ_ATTRIBUTES            = const_cpu_to_le32(0x00000080),

        /* Right to change file attributes. (FILE/DIRECTORY) */
        FILE_WRITE_ATTRIBUTES           = const_cpu_to_le32(0x00000100),

        /*
         * The standard rights (bits 16 to 23).  These are independent of the
         * type of object being secured.
         */

        /* Right to delete the object. */
        DELETE                          = const_cpu_to_le32(0x00010000),

        /*
         * Right to read the information in the object's security descriptor,
         * not including the information in the SACL, i.e. right to read the
         * security descriptor and owner.
         */
        READ_CONTROL                    = const_cpu_to_le32(0x00020000),

        /* Right to modify the DACL in the object's security descriptor. */
        WRITE_DAC                       = const_cpu_to_le32(0x00040000),

        /* Right to change the owner in the object's security descriptor. */
        WRITE_OWNER                     = const_cpu_to_le32(0x00080000),

        /*
         * Right to use the object for synchronization.  Enables a process to
         * wait until the object is in the signalled state.  Some object types
         * do not support this access right.
         */
        SYNCHRONIZE                     = const_cpu_to_le32(0x00100000),

        /*
         * The following STANDARD_RIGHTS_* are combinations of the above for
         * convenience and are defined by the Win32 API.
         */

        /* These are currently defined to READ_CONTROL. */
        STANDARD_RIGHTS_READ            = const_cpu_to_le32(0x00020000),
        STANDARD_RIGHTS_WRITE           = const_cpu_to_le32(0x00020000),
        STANDARD_RIGHTS_EXECUTE         = const_cpu_to_le32(0x00020000),

        /* Combines DELETE, READ_CONTROL, WRITE_DAC, and WRITE_OWNER access. */
        STANDARD_RIGHTS_REQUIRED        = const_cpu_to_le32(0x000f0000),

        /*
         * Combines DELETE, READ_CONTROL, WRITE_DAC, WRITE_OWNER, and
         * SYNCHRONIZE access.
         */
        STANDARD_RIGHTS_ALL             = const_cpu_to_le32(0x001f0000),

        /*
         * The access system ACL and maximum allowed access types (bits 24 to
         * 25, bits 26 to 27 are reserved).
         */
        ACCESS_SYSTEM_SECURITY          = const_cpu_to_le32(0x01000000),
        MAXIMUM_ALLOWED                 = const_cpu_to_le32(0x02000000),

        /*
         * The generic rights (bits 28 to 31).  These map onto the standard and
         * specific rights.
         */

        /* Read, write, and execute access. */
        GENERIC_ALL                     = const_cpu_to_le32(0x10000000),

        /* Execute access. */
        GENERIC_EXECUTE                 = const_cpu_to_le32(0x20000000),

        /*
         * Write access.  For files, this maps onto:
         *      FILE_APPEND_DATA | FILE_WRITE_ATTRIBUTES | FILE_WRITE_DATA |
         *      FILE_WRITE_EA | STANDARD_RIGHTS_WRITE | SYNCHRONIZE
         * For directories, the mapping has the same numerical value.  See
         * above for the descriptions of the rights granted.
         */
        GENERIC_WRITE                   = const_cpu_to_le32(0x40000000),

        /*
         * Read access.  For files, this maps onto:
         *      FILE_READ_ATTRIBUTES | FILE_READ_DATA | FILE_READ_EA |
         *      STANDARD_RIGHTS_READ | SYNCHRONIZE
         * For directories, the mapping has the same numberical value.  See
         * above for the descriptions of the rights granted.
         */
        GENERIC_READ                    = const_cpu_to_le32(0x80000000),
};

typedef le32 ACCESS_MASK;

/*
 * The generic mapping array. Used to denote the mapping of each generic
 * access right to a specific access mask.
 *
 * FIXME: What exactly is this and what is it for? (AIA)
 */
typedef struct {
        ACCESS_MASK generic_read;
        ACCESS_MASK generic_write;
        ACCESS_MASK generic_execute;
        ACCESS_MASK generic_all;
} __attribute__ ((__packed__)) GENERIC_MAPPING;

/*
 * The predefined ACE type structures are as defined below.
 */

/*
 * ACCESS_ALLOWED_ACE, ACCESS_DENIED_ACE, SYSTEM_AUDIT_ACE, SYSTEM_ALARM_ACE
 */
typedef struct {
/*  0   ACE_HEADER; -- Unfolded here as gcc doesn't like unnamed structs. */
        ACE_TYPES type;         /* Type of the ACE. */
        ACE_FLAGS flags;        /* Flags describing the ACE. */
        le16 size;              /* Size in bytes of the ACE. */
/*  4*/ ACCESS_MASK mask;       /* Access mask associated with the ACE. */

/*  8*/ SID sid;                /* The SID associated with the ACE. */
} __attribute__ ((__packed__)) ACCESS_ALLOWED_ACE, ACCESS_DENIED_ACE,
                               SYSTEM_AUDIT_ACE, SYSTEM_ALARM_ACE;

/*
 * The object ACE flags (32-bit).
 */
enum {
        ACE_OBJECT_TYPE_PRESENT                 = const_cpu_to_le32(1),
        ACE_INHERITED_OBJECT_TYPE_PRESENT       = const_cpu_to_le32(2),
};

typedef le32 OBJECT_ACE_FLAGS;

typedef struct {
/*  0   ACE_HEADER; -- Unfolded here as gcc doesn't like unnamed structs. */
        ACE_TYPES type;         /* Type of the ACE. */
        ACE_FLAGS flags;        /* Flags describing the ACE. */
        le16 size;              /* Size in bytes of the ACE. */
/*  4*/ ACCESS_MASK mask;       /* Access mask associated with the ACE. */

/*  8*/ OBJECT_ACE_FLAGS object_flags;  /* Flags describing the object ACE. */
/* 12*/ GUID object_type;
/* 28*/ GUID inherited_object_type;

/* 44*/ SID sid;                /* The SID associated with the ACE. */
} __attribute__ ((__packed__)) ACCESS_ALLOWED_OBJECT_ACE,
                               ACCESS_DENIED_OBJECT_ACE,
                               SYSTEM_AUDIT_OBJECT_ACE,
                               SYSTEM_ALARM_OBJECT_ACE;

/*
 * An ACL is an access-control list (ACL).
 * An ACL starts with an ACL header structure, which specifies the size of
 * the ACL and the number of ACEs it contains. The ACL header is followed by
 * zero or more access control entries (ACEs). The ACL as well as each ACE
 * are aligned on 4-byte boundaries.
 */
typedef struct {
        u8 revision;    /* Revision of this ACL. */
        u8 alignment1;
        le16 size;      /* Allocated space in bytes for ACL. Includes this
                           header, the ACEs and the remaining free space. */
        le16 ace_count; /* Number of ACEs in the ACL. */
        le16 alignment2;
/* sizeof() = 8 bytes */
} __attribute__ ((__packed__)) ACL;

/*
 * Current constants for ACLs.
 */
typedef enum {
        /* Current revision. */
        ACL_REVISION            = 2,
        ACL_REVISION_DS         = 4,

        /* History of revisions. */
        ACL_REVISION1           = 1,
        MIN_ACL_REVISION        = 2,
        ACL_REVISION2           = 2,
        ACL_REVISION3           = 3,
        ACL_REVISION4           = 4,
        MAX_ACL_REVISION        = 4,
} ACL_CONSTANTS;

/*
 * The security descriptor control flags (16-bit).
 *
 * SE_OWNER_DEFAULTED - This boolean flag, when set, indicates that the SID
 *      pointed to by the Owner field was provided by a defaulting mechanism
 *      rather than explicitly provided by the original provider of the
 *      security descriptor.  This may affect the treatment of the SID with
 *      respect to inheritence of an owner.
 *
 * SE_GROUP_DEFAULTED - This boolean flag, when set, indicates that the SID in
 *      the Group field was provided by a defaulting mechanism rather than
 *      explicitly provided by the original provider of the security
 *      descriptor.  This may affect the treatment of the SID with respect to
 *      inheritence of a primary group.
 *
 * SE_DACL_PRESENT - This boolean flag, when set, indicates that the security
 *      descriptor contains a discretionary ACL.  If this flag is set and the
 *      Dacl field of the SECURITY_DESCRIPTOR is null, then a null ACL is
 *      explicitly being specified.
 *
 * SE_DACL_DEFAULTED - This boolean flag, when set, indicates that the ACL
 *      pointed to by the Dacl field was provided by a defaulting mechanism
 *      rather than explicitly provided by the original provider of the
 *      security descriptor.  This may affect the treatment of the ACL with
 *      respect to inheritence of an ACL.  This flag is ignored if the
 *      DaclPresent flag is not set.
 *
 * SE_SACL_PRESENT - This boolean flag, when set,  indicates that the security
 *      descriptor contains a system ACL pointed to by the Sacl field.  If this
 *      flag is set and the Sacl field of the SECURITY_DESCRIPTOR is null, then
 *      an empty (but present) ACL is being specified.
 *
 * SE_SACL_DEFAULTED - This boolean flag, when set, indicates that the ACL
 *      pointed to by the Sacl field was provided by a defaulting mechanism
 *      rather than explicitly provided by the original provider of the
 *      security descriptor.  This may affect the treatment of the ACL with
 *      respect to inheritence of an ACL.  This flag is ignored if the
 *      SaclPresent flag is not set.
 *
 * SE_SELF_RELATIVE - This boolean flag, when set, indicates that the security
 *      descriptor is in self-relative form.  In this form, all fields of the
 *      security descriptor are contiguous in memory and all pointer fields are
 *      expressed as offsets from the beginning of the security descriptor.
 */
enum {
        SE_OWNER_DEFAULTED              = const_cpu_to_le16(0x0001),
        SE_GROUP_DEFAULTED              = const_cpu_to_le16(0x0002),
        SE_DACL_PRESENT                 = const_cpu_to_le16(0x0004),
        SE_DACL_DEFAULTED               = const_cpu_to_le16(0x0008),

        SE_SACL_PRESENT                 = const_cpu_to_le16(0x0010),
        SE_SACL_DEFAULTED               = const_cpu_to_le16(0x0020),

        SE_DACL_AUTO_INHERIT_REQ        = const_cpu_to_le16(0x0100),
        SE_SACL_AUTO_INHERIT_REQ        = const_cpu_to_le16(0x0200),
        SE_DACL_AUTO_INHERITED          = const_cpu_to_le16(0x0400),
        SE_SACL_AUTO_INHERITED          = const_cpu_to_le16(0x0800),

        SE_DACL_PROTECTED               = const_cpu_to_le16(0x1000),
        SE_SACL_PROTECTED               = const_cpu_to_le16(0x2000),
        SE_RM_CONTROL_VALID             = const_cpu_to_le16(0x4000),
        SE_SELF_RELATIVE                = const_cpu_to_le16(0x8000)
} __attribute__ ((__packed__));

typedef le16 SECURITY_DESCRIPTOR_CONTROL;

/*
 * Self-relative security descriptor. Contains the owner and group SIDs as well
 * as the sacl and dacl ACLs inside the security descriptor itself.
 */
typedef struct {
        u8 revision;    /* Revision level of the security descriptor. */
        u8 alignment;
        SECURITY_DESCRIPTOR_CONTROL control; /* Flags qualifying the type of
                           the descriptor as well as the following fields. */
        le32 owner;     /* Byte offset to a SID representing an object's
                           owner. If this is NULL, no owner SID is present in
                           the descriptor. */
        le32 group;     /* Byte offset to a SID representing an object's
                           primary group. If this is NULL, no primary group
                           SID is present in the descriptor. */
        le32 sacl;      /* Byte offset to a system ACL. Only valid, if
                           SE_SACL_PRESENT is set in the control field. If
                           SE_SACL_PRESENT is set but sacl is NULL, a NULL ACL
                           is specified. */
        le32 dacl;      /* Byte offset to a discretionary ACL. Only valid, if
                           SE_DACL_PRESENT is set in the control field. If
                           SE_DACL_PRESENT is set but dacl is NULL, a NULL ACL
                           (unconditionally granting access) is specified. */
/* sizeof() = 0x14 bytes */
} __attribute__ ((__packed__)) SECURITY_DESCRIPTOR_RELATIVE;

/*
 * Absolute security descriptor. Does not contain the owner and group SIDs, nor
 * the sacl and dacl ACLs inside the security descriptor. Instead, it contains
 * pointers to these structures in memory. Obviously, absolute security
 * descriptors are only useful for in memory representations of security
 * descriptors. On disk, a self-relative security descriptor is used.
 */
typedef struct {
        u8 revision;    /* Revision level of the security descriptor. */
        u8 alignment;
        SECURITY_DESCRIPTOR_CONTROL control;    /* Flags qualifying the type of
                           the descriptor as well as the following fields. */
        SID *owner;     /* Points to a SID representing an object's owner. If
                           this is NULL, no owner SID is present in the
                           descriptor. */
        SID *group;     /* Points to a SID representing an object's primary
                           group. If this is NULL, no primary group SID is
                           present in the descriptor. */
        ACL *sacl;      /* Points to a system ACL. Only valid, if
                           SE_SACL_PRESENT is set in the control field. If
                           SE_SACL_PRESENT is set but sacl is NULL, a NULL ACL
                           is specified. */
        ACL *dacl;      /* Points to a discretionary ACL. Only valid, if
                           SE_DACL_PRESENT is set in the control field. If
                           SE_DACL_PRESENT is set but dacl is NULL, a NULL ACL
                           (unconditionally granting access) is specified. */
} __attribute__ ((__packed__)) SECURITY_DESCRIPTOR;

/*
 * Current constants for security descriptors.
 */
typedef enum {
        /* Current revision. */
        SECURITY_DESCRIPTOR_REVISION    = 1,
        SECURITY_DESCRIPTOR_REVISION1   = 1,

        /* The sizes of both the absolute and relative security descriptors is
           the same as pointers, at least on ia32 architecture are 32-bit. */
        SECURITY_DESCRIPTOR_MIN_LENGTH  = sizeof(SECURITY_DESCRIPTOR),
} SECURITY_DESCRIPTOR_CONSTANTS;

/*
 * Attribute: Security descriptor (0x50). A standard self-relative security
 * descriptor.
 *
 * NOTE: Can be resident or non-resident.
 * NOTE: Not used in NTFS 3.0+, as security descriptors are stored centrally
 * in FILE_Secure and the correct descriptor is found using the security_id
 * from the standard information attribute.
 */
typedef SECURITY_DESCRIPTOR_RELATIVE SECURITY_DESCRIPTOR_ATTR;

/*
 * On NTFS 3.0+, all security descriptors are stored in FILE_Secure. Only one
 * referenced instance of each unique security descriptor is stored.
 *
 * FILE_Secure contains no unnamed data attribute, i.e. it has zero length. It
 * does, however, contain two indexes ($SDH and $SII) as well as a named data
 * stream ($SDS).
 *
 * Every unique security descriptor is assigned a unique security identifier
 * (security_id, not to be confused with a SID). The security_id is unique for
 * the NTFS volume and is used as an index into the $SII index, which maps
 * security_ids to the security descriptor's storage location within the $SDS
 * data attribute. The $SII index is sorted by ascending security_id.
 *
 * A simple hash is computed from each security descriptor. This hash is used
 * as an index into the $SDH index, which maps security descriptor hashes to
 * the security descriptor's storage location within the $SDS data attribute.
 * The $SDH index is sorted by security descriptor hash and is stored in a B+
 * tree. When searching $SDH (with the intent of determining whether or not a
 * new security descriptor is already present in the $SDS data stream), if a
 * matching hash is found, but the security descriptors do not match, the
 * search in the $SDH index is continued, searching for a next matching hash.
 *
 * When a precise match is found, the security_id coresponding to the security
 * descriptor in the $SDS attribute is read from the found $SDH index entry and
 * is stored in the $STANDARD_INFORMATION attribute of the file/directory to
 * which the security descriptor is being applied. The $STANDARD_INFORMATION
 * attribute is present in all base mft records (i.e. in all files and
 * directories).
 *
 * If a match is not found, the security descriptor is assigned a new unique
 * security_id and is added to the $SDS data attribute. Then, entries
 * referencing the this security descriptor in the $SDS data attribute are
 * added to the $SDH and $SII indexes.
 *
 * Note: Entries are never deleted from FILE_Secure, even if nothing
 * references an entry any more.
 */

/*
 * This header precedes each security descriptor in the $SDS data stream.
 * This is also the index entry data part of both the $SII and $SDH indexes.
 */
typedef struct {
        le32 hash;        /* Hash of the security descriptor. */
        le32 security_id; /* The security_id assigned to the descriptor. */
        le64 offset;      /* Byte offset of this entry in the $SDS stream. */
        le32 length;      /* Size in bytes of this entry in $SDS stream. */
} __attribute__ ((__packed__)) SECURITY_DESCRIPTOR_HEADER;

/*
 * The $SDS data stream contains the security descriptors, aligned on 16-byte
 * boundaries, sorted by security_id in a B+ tree. Security descriptors cannot
 * cross 256kib boundaries (this restriction is imposed by the Windows cache
 * manager). Each security descriptor is contained in a SDS_ENTRY structure.
 * Also, each security descriptor is stored twice in the $SDS stream with a
 * fixed offset of 0x40000 bytes (256kib, the Windows cache manager's max size)
 * between them; i.e. if a SDS_ENTRY specifies an offset of 0x51d0, then the
 * the first copy of the security descriptor will be at offset 0x51d0 in the
 * $SDS data stream and the second copy will be at offset 0x451d0.
 */
typedef struct {
/*Ofs*/
/*  0   SECURITY_DESCRIPTOR_HEADER; -- Unfolded here as gcc doesn't like
                                       unnamed structs. */
        le32 hash;        /* Hash of the security descriptor. */
        le32 security_id; /* The security_id assigned to the descriptor. */
        le64 offset;      /* Byte offset of this entry in the $SDS stream. */
        le32 length;      /* Size in bytes of this entry in $SDS stream. */
/* 20*/ SECURITY_DESCRIPTOR_RELATIVE sid; /* The self-relative security
                                             descriptor. */
} __attribute__ ((__packed__)) SDS_ENTRY;

/*
 * The index entry key used in the $SII index. The collation type is
 * COLLATION_NTOFS_ULONG.
 */
typedef struct {
        le32 security_id; /* The security_id assigned to the descriptor. */
} __attribute__ ((__packed__)) SII_INDEX_KEY;

/*
 * The index entry key used in the $SDH index. The keys are sorted first by
 * hash and then by security_id. The collation rule is
 * COLLATION_NTOFS_SECURITY_HASH.
 */
typedef struct {
        le32 hash;        /* Hash of the security descriptor. */
        le32 security_id; /* The security_id assigned to the descriptor. */
} __attribute__ ((__packed__)) SDH_INDEX_KEY;

/*
 * Attribute: Volume name (0x60).
 *
 * NOTE: Always resident.
 * NOTE: Present only in FILE_Volume.
 */
typedef struct {
        ntfschar name[0];       /* The name of the volume in Unicode. */
} __attribute__ ((__packed__)) VOLUME_NAME;

/*
 * Possible flags for the volume (16-bit).
 */
enum {
        VOLUME_IS_DIRTY                 = const_cpu_to_le16(0x0001),
        VOLUME_RESIZE_LOG_FILE          = const_cpu_to_le16(0x0002),
        VOLUME_UPGRADE_ON_MOUNT         = const_cpu_to_le16(0x0004),
        VOLUME_MOUNTED_ON_NT4           = const_cpu_to_le16(0x0008),

        VOLUME_DELETE_USN_UNDERWAY      = const_cpu_to_le16(0x0010),
        VOLUME_REPAIR_OBJECT_ID         = const_cpu_to_le16(0x0020),

        VOLUME_MODIFIED_BY_CHKDSK       = const_cpu_to_le16(0x8000),

        VOLUME_FLAGS_MASK               = const_cpu_to_le16(0x803f),

        /* To make our life easier when checking if we must mount read-only. */
        VOLUME_MUST_MOUNT_RO_MASK       = const_cpu_to_le16(0x8037),
} __attribute__ ((__packed__));

typedef le16 VOLUME_FLAGS;

/*
 * Attribute: Volume information (0x70).
 *
 * NOTE: Always resident.
 * NOTE: Present only in FILE_Volume.
 * NOTE: Windows 2000 uses NTFS 3.0 while Windows NT4 service pack 6a uses
 *       NTFS 1.2. I haven't personally seen other values yet.
 */
typedef struct {
        le64 reserved;          /* Not used (yet?). */
        u8 major_ver;           /* Major version of the ntfs format. */
        u8 minor_ver;           /* Minor version of the ntfs format. */
        VOLUME_FLAGS flags;     /* Bit array of VOLUME_* flags. */
} __attribute__ ((__packed__)) VOLUME_INFORMATION;

/*
 * Attribute: Data attribute (0x80).
 *
 * NOTE: Can be resident or non-resident.
 *
 * Data contents of a file (i.e. the unnamed stream) or of a named stream.
 */
typedef struct {
        u8 data[0];             /* The file's data contents. */
} __attribute__ ((__packed__)) DATA_ATTR;

/*
 * Index header flags (8-bit).
 */
enum {
        /*
         * When index header is in an index root attribute:
         */
        SMALL_INDEX = 0, /* The index is small enough to fit inside the index
                            root attribute and there is no index allocation
                            attribute present. */
        LARGE_INDEX = 1, /* The index is too large to fit in the index root
                            attribute and/or an index allocation attribute is
                            present. */
        /*
         * When index header is in an index block, i.e. is part of index
         * allocation attribute:
         */
        LEAF_NODE  = 0, /* This is a leaf node, i.e. there are no more nodes
                           branching off it. */
        INDEX_NODE = 1, /* This node indexes other nodes, i.e. it is not a leaf
                           node. */
        NODE_MASK  = 1, /* Mask for accessing the *_NODE bits. */
} __attribute__ ((__packed__));

typedef u8 INDEX_HEADER_FLAGS;

/*
 * This is the header for indexes, describing the INDEX_ENTRY records, which
 * follow the INDEX_HEADER. Together the index header and the index entries
 * make up a complete index.
 *
 * IMPORTANT NOTE: The offset, length and size structure members are counted
 * relative to the start of the index header structure and not relative to the
 * start of the index root or index allocation structures themselves.
 */
typedef struct {
        le32 entries_offset;            /* Byte offset to first INDEX_ENTRY
                                           aligned to 8-byte boundary. */
        le32 index_length;              /* Data size of the index in bytes,
                                           i.e. bytes used from allocated
                                           size, aligned to 8-byte boundary. */
        le32 allocated_size;            /* Byte size of this index (block),
                                           multiple of 8 bytes. */
        /* NOTE: For the index root attribute, the above two numbers are always
           equal, as the attribute is resident and it is resized as needed. In
           the case of the index allocation attribute the attribute is not
           resident and hence the allocated_size is a fixed value and must
           equal the index_block_size specified by the INDEX_ROOT attribute
           corresponding to the INDEX_ALLOCATION attribute this INDEX_BLOCK
           belongs to. */
        INDEX_HEADER_FLAGS flags;       /* Bit field of INDEX_HEADER_FLAGS. */
        u8 reserved[3];                 /* Reserved/align to 8-byte boundary. */
} __attribute__ ((__packed__)) INDEX_HEADER;

/*
 * Attribute: Index root (0x90).
 *
 * NOTE: Always resident.
 *
 * This is followed by a sequence of index entries (INDEX_ENTRY structures)
 * as described by the index header.
 *
 * When a directory is small enough to fit inside the index root then this
 * is the only attribute describing the directory. When the directory is too
 * large to fit in the index root, on the other hand, two aditional attributes
 * are present: an index allocation attribute, containing sub-nodes of the B+
 * directory tree (see below), and a bitmap attribute, describing which virtual
 * cluster numbers (vcns) in the index allocation attribute are in use by an
 * index block.
 *
 * NOTE: The root directory (FILE_root) contains an entry for itself. Other
 * dircetories do not contain entries for themselves, though.
 */
typedef struct {
        ATTR_TYPE type;                 /* Type of the indexed attribute. Is
                                           $FILE_NAME for directories, zero
                                           for view indexes. No other values
                                           allowed. */
        COLLATION_RULE collation_rule;  /* Collation rule used to sort the
                                           index entries. If type is $FILE_NAME,
                                           this must be COLLATION_FILE_NAME. */
        le32 index_block_size;          /* Size of each index block in bytes (in
                                           the index allocation attribute). */
        u8 clusters_per_index_block;    /* Cluster size of each index block (in
                                           the index allocation attribute), when
                                           an index block is >= than a cluster,
                                           otherwise this will be the log of
                                           the size (like how the encoding of
                                           the mft record size and the index
                                           record size found in the boot sector
                                           work). Has to be a power of 2. */
        u8 reserved[3];                 /* Reserved/align to 8-byte boundary. */
        INDEX_HEADER index;             /* Index header describing the
                                           following index entries. */
} __attribute__ ((__packed__)) INDEX_ROOT;

/*
 * Attribute: Index allocation (0xa0).
 *
 * NOTE: Always non-resident (doesn't make sense to be resident anyway!).
 *
 * This is an array of index blocks. Each index block starts with an
 * INDEX_BLOCK structure containing an index header, followed by a sequence of
 * index entries (INDEX_ENTRY structures), as described by the INDEX_HEADER.
 */
typedef struct {
/*  0   NTFS_RECORD; -- Unfolded here as gcc doesn't like unnamed structs. */
        NTFS_RECORD_TYPE magic; /* Magic is "INDX". */
        le16 usa_ofs;           /* See NTFS_RECORD definition. */
        le16 usa_count;         /* See NTFS_RECORD definition. */

/*  8*/ sle64 lsn;              /* $LogFile sequence number of the last
                                   modification of this index block. */
/* 16*/ leVCN index_block_vcn;  /* Virtual cluster number of the index block.
                                   If the cluster_size on the volume is <= the
                                   index_block_size of the directory,
                                   index_block_vcn counts in units of clusters,
                                   and in units of sectors otherwise. */
/* 24*/ INDEX_HEADER index;     /* Describes the following index entries. */
/* sizeof()= 40 (0x28) bytes */
/*
 * When creating the index block, we place the update sequence array at this
 * offset, i.e. before we start with the index entries. This also makes sense,
 * otherwise we could run into problems with the update sequence array
 * containing in itself the last two bytes of a sector which would mean that
 * multi sector transfer protection wouldn't work. As you can't protect data
 * by overwriting it since you then can't get it back...
 * When reading use the data from the ntfs record header.
 */
} __attribute__ ((__packed__)) INDEX_BLOCK;

typedef INDEX_BLOCK INDEX_ALLOCATION;

/*
 * The system file FILE_Extend/$Reparse contains an index named $R listing
 * all reparse points on the volume. The index entry keys are as defined
 * below. Note, that there is no index data associated with the index entries.
 *
 * The index entries are sorted by the index key file_id. The collation rule is
 * COLLATION_NTOFS_ULONGS. FIXME: Verify whether the reparse_tag is not the
 * primary key / is not a key at all. (AIA)
 */
typedef struct {
        le32 reparse_tag;       /* Reparse point type (inc. flags). */
        leMFT_REF file_id;      /* Mft record of the file containing the
                                   reparse point attribute. */
} __attribute__ ((__packed__)) REPARSE_INDEX_KEY;

/*
 * Quota flags (32-bit).
 *
 * The user quota flags.  Names explain meaning.
 */
enum {
        QUOTA_FLAG_DEFAULT_LIMITS       = const_cpu_to_le32(0x00000001),
        QUOTA_FLAG_LIMIT_REACHED        = const_cpu_to_le32(0x00000002),
        QUOTA_FLAG_ID_DELETED           = const_cpu_to_le32(0x00000004),

        QUOTA_FLAG_USER_MASK            = const_cpu_to_le32(0x00000007),
        /* This is a bit mask for the user quota flags. */

        /*
         * These flags are only present in the quota defaults index entry, i.e.
         * in the entry where owner_id = QUOTA_DEFAULTS_ID.
         */
        QUOTA_FLAG_TRACKING_ENABLED     = const_cpu_to_le32(0x00000010),
        QUOTA_FLAG_ENFORCEMENT_ENABLED  = const_cpu_to_le32(0x00000020),
        QUOTA_FLAG_TRACKING_REQUESTED   = const_cpu_to_le32(0x00000040),
        QUOTA_FLAG_LOG_THRESHOLD        = const_cpu_to_le32(0x00000080),

        QUOTA_FLAG_LOG_LIMIT            = const_cpu_to_le32(0x00000100),
        QUOTA_FLAG_OUT_OF_DATE          = const_cpu_to_le32(0x00000200),
        QUOTA_FLAG_CORRUPT              = const_cpu_to_le32(0x00000400),
        QUOTA_FLAG_PENDING_DELETES      = const_cpu_to_le32(0x00000800),
};

typedef le32 QUOTA_FLAGS;

/*
 * The system file FILE_Extend/$Quota contains two indexes $O and $Q. Quotas
 * are on a per volume and per user basis.
 *
 * The $Q index contains one entry for each existing user_id on the volume. The
 * index key is the user_id of the user/group owning this quota control entry,
 * i.e. the key is the owner_id. The user_id of the owner of a file, i.e. the
 * owner_id, is found in the standard information attribute. The collation rule
 * for $Q is COLLATION_NTOFS_ULONG.
 *
 * The $O index contains one entry for each user/group who has been assigned
 * a quota on that volume. The index key holds the SID of the user_id the
 * entry belongs to, i.e. the owner_id. The collation rule for $O is
 * COLLATION_NTOFS_SID.
 *
 * The $O index entry data is the user_id of the user corresponding to the SID.
 * This user_id is used as an index into $Q to find the quota control entry
 * associated with the SID.
 *
 * The $Q index entry data is the quota control entry and is defined below.
 */
typedef struct {
        le32 version;           /* Currently equals 2. */
        QUOTA_FLAGS flags;      /* Flags describing this quota entry. */
        le64 bytes_used;        /* How many bytes of the quota are in use. */
        sle64 change_time;      /* Last time this quota entry was changed. */
        sle64 threshold;        /* Soft quota (-1 if not limited). */
        sle64 limit;            /* Hard quota (-1 if not limited). */
        sle64 exceeded_time;    /* How long the soft quota has been exceeded. */
        SID sid;                /* The SID of the user/object associated with
                                   this quota entry.  Equals zero for the quota
                                   defaults entry (and in fact on a WinXP
                                   volume, it is not present at all). */
} __attribute__ ((__packed__)) QUOTA_CONTROL_ENTRY;

/*
 * Predefined owner_id values (32-bit).
 */
enum {
        QUOTA_INVALID_ID        = const_cpu_to_le32(0x00000000),
        QUOTA_DEFAULTS_ID       = const_cpu_to_le32(0x00000001),
        QUOTA_FIRST_USER_ID     = const_cpu_to_le32(0x00000100),
};

/*
 * Current constants for quota control entries.
 */
typedef enum {
        /* Current version. */
        QUOTA_VERSION   = 2,
} QUOTA_CONTROL_ENTRY_CONSTANTS;

/*
 * Index entry flags (16-bit).
 */
enum {
        INDEX_ENTRY_NODE = const_cpu_to_le16(1), /* This entry contains a
                        sub-node, i.e. a reference to an index block in form of
                        a virtual cluster number (see below). */
        INDEX_ENTRY_END  = const_cpu_to_le16(2), /* This signifies the last
                        entry in an index block.  The index entry does not
                        represent a file but it can point to a sub-node. */

        INDEX_ENTRY_SPACE_FILLER = const_cpu_to_le16(0xffff), /* gcc: Force
                        enum bit width to 16-bit. */
} __attribute__ ((__packed__));

typedef le16 INDEX_ENTRY_FLAGS;

/*
 * This the index entry header (see below).
 */
typedef struct {
/*  0*/ union {
                struct { /* Only valid when INDEX_ENTRY_END is not set. */
                        leMFT_REF indexed_file; /* The mft reference of the file
                                                   described by this index
                                                   entry. Used for directory
                                                   indexes. */
                } __attribute__ ((__packed__)) dir;
                struct { /* Used for views/indexes to find the entry's data. */
                        le16 data_offset;       /* Data byte offset from this
                                                   INDEX_ENTRY. Follows the
                                                   index key. */
                        le16 data_length;       /* Data length in bytes. */
                        le32 reservedV;         /* Reserved (zero). */
                } __attribute__ ((__packed__)) vi;
        } __attribute__ ((__packed__)) data;
/*  8*/ le16 length;             /* Byte size of this index entry, multiple of
                                    8-bytes. */
/* 10*/ le16 key_length;         /* Byte size of the key value, which is in the
                                    index entry. It follows field reserved. Not
                                    multiple of 8-bytes. */
/* 12*/ INDEX_ENTRY_FLAGS flags; /* Bit field of INDEX_ENTRY_* flags. */
/* 14*/ le16 reserved;           /* Reserved/align to 8-byte boundary. */
/* sizeof() = 16 bytes */
} __attribute__ ((__packed__)) INDEX_ENTRY_HEADER;

/*
 * This is an index entry. A sequence of such entries follows each INDEX_HEADER
 * structure. Together they make up a complete index. The index follows either
 * an index root attribute or an index allocation attribute.
 *
 * NOTE: Before NTFS 3.0 only filename attributes were indexed.
 */
typedef struct {
/*Ofs*/
/*  0   INDEX_ENTRY_HEADER; -- Unfolded here as gcc dislikes unnamed structs. */
        union {
                struct { /* Only valid when INDEX_ENTRY_END is not set. */
                        leMFT_REF indexed_file; /* The mft reference of the file
                                                   described by this index
                                                   entry. Used for directory
                                                   indexes. */
                } __attribute__ ((__packed__)) dir;
                struct { /* Used for views/indexes to find the entry's data. */
                        le16 data_offset;       /* Data byte offset from this
                                                   INDEX_ENTRY. Follows the
                                                   index key. */
                        le16 data_length;       /* Data length in bytes. */
                        le32 reservedV;         /* Reserved (zero). */
                } __attribute__ ((__packed__)) vi;
        } __attribute__ ((__packed__)) data;
        le16 length;             /* Byte size of this index entry, multiple of
                                    8-bytes. */
        le16 key_length;         /* Byte size of the key value, which is in the
                                    index entry. It follows field reserved. Not
                                    multiple of 8-bytes. */
        INDEX_ENTRY_FLAGS flags; /* Bit field of INDEX_ENTRY_* flags. */
        le16 reserved;           /* Reserved/align to 8-byte boundary. */

/* 16*/ union {         /* The key of the indexed attribute. NOTE: Only present
                           if INDEX_ENTRY_END bit in flags is not set. NOTE: On
                           NTFS versions before 3.0 the only valid key is the
                           FILE_NAME_ATTR. On NTFS 3.0+ the following
                           additional index keys are defined: */
                FILE_NAME_ATTR file_name;/* $I30 index in directories. */
                SII_INDEX_KEY sii;      /* $SII index in $Secure. */
                SDH_INDEX_KEY sdh;      /* $SDH index in $Secure. */
                GUID object_id;         /* $O index in FILE_Extend/$ObjId: The
                                           object_id of the mft record found in
                                           the data part of the index. */
                REPARSE_INDEX_KEY reparse;      /* $R index in
                                                   FILE_Extend/$Reparse. */
                SID sid;                /* $O index in FILE_Extend/$Quota:
                                           SID of the owner of the user_id. */
                le32 owner_id;          /* $Q index in FILE_Extend/$Quota:
                                           user_id of the owner of the quota
                                           control entry in the data part of
                                           the index. */
        } __attribute__ ((__packed__)) key;
        /* The (optional) index data is inserted here when creating. */
        // leVCN vcn;   /* If INDEX_ENTRY_NODE bit in flags is set, the last
        //                 eight bytes of this index entry contain the virtual
        //                 cluster number of the index block that holds the
        //                 entries immediately preceding the current entry (the
        //                 vcn references the corresponding cluster in the data
        //                 of the non-resident index allocation attribute). If
        //                 the key_length is zero, then the vcn immediately
        //                 follows the INDEX_ENTRY_HEADER. Regardless of
        //                 key_length, the address of the 8-byte boundary
        //                 alligned vcn of INDEX_ENTRY{_HEADER} *ie is given by
        //                 (char*)ie + le16_to_cpu(ie*)->length) - sizeof(VCN),
        //                 where sizeof(VCN) can be hardcoded as 8 if wanted. */
} __attribute__ ((__packed__)) INDEX_ENTRY;

/*
 * Attribute: Bitmap (0xb0).
 *
 * Contains an array of bits (aka a bitfield).
 *
 * When used in conjunction with the index allocation attribute, each bit
 * corresponds to one index block within the index allocation attribute. Thus
 * the number of bits in the bitmap * index block size / cluster size is the
 * number of clusters in the index allocation attribute.
 */
typedef struct {
        u8 bitmap[0];                   /* Array of bits. */
} __attribute__ ((__packed__)) BITMAP_ATTR;

/*
 * The reparse point tag defines the type of the reparse point. It also
 * includes several flags, which further describe the reparse point.
 *
 * The reparse point tag is an unsigned 32-bit value divided in three parts:
 *
 * 1. The least significant 16 bits (i.e. bits 0 to 15) specifiy the type of
 *    the reparse point.
 * 2. The 13 bits after this (i.e. bits 16 to 28) are reserved for future use.
 * 3. The most significant three bits are flags describing the reparse point.
 *    They are defined as follows:
 *      bit 29: Name surrogate bit. If set, the filename is an alias for
 *              another object in the system.
 *      bit 30: High-latency bit. If set, accessing the first byte of data will
 *              be slow. (E.g. the data is stored on a tape drive.)
 *      bit 31: Microsoft bit. If set, the tag is owned by Microsoft. User
 *              defined tags have to use zero here.
 *
 * These are the predefined reparse point tags:
 */
enum {
        IO_REPARSE_TAG_IS_ALIAS         = const_cpu_to_le32(0x20000000),
        IO_REPARSE_TAG_IS_HIGH_LATENCY  = const_cpu_to_le32(0x40000000),
        IO_REPARSE_TAG_IS_MICROSOFT     = const_cpu_to_le32(0x80000000),

        IO_REPARSE_TAG_RESERVED_ZERO    = const_cpu_to_le32(0x00000000),
        IO_REPARSE_TAG_RESERVED_ONE     = const_cpu_to_le32(0x00000001),
        IO_REPARSE_TAG_RESERVED_RANGE   = const_cpu_to_le32(0x00000001),

        IO_REPARSE_TAG_NSS              = const_cpu_to_le32(0x68000005),
        IO_REPARSE_TAG_NSS_RECOVER      = const_cpu_to_le32(0x68000006),
        IO_REPARSE_TAG_SIS              = const_cpu_to_le32(0x68000007),
        IO_REPARSE_TAG_DFS              = const_cpu_to_le32(0x68000008),

        IO_REPARSE_TAG_MOUNT_POINT      = const_cpu_to_le32(0x88000003),

        IO_REPARSE_TAG_HSM              = const_cpu_to_le32(0xa8000004),

        IO_REPARSE_TAG_SYMBOLIC_LINK    = const_cpu_to_le32(0xe8000000),

        IO_REPARSE_TAG_VALID_VALUES     = const_cpu_to_le32(0xe000ffff),
};

/*
 * Attribute: Reparse point (0xc0).
 *
 * NOTE: Can be resident or non-resident.
 */
typedef struct {
        le32 reparse_tag;               /* Reparse point type (inc. flags). */
        le16 reparse_data_length;       /* Byte size of reparse data. */
        le16 reserved;                  /* Align to 8-byte boundary. */
        u8 reparse_data[0];             /* Meaning depends on reparse_tag. */
} __attribute__ ((__packed__)) REPARSE_POINT;

/*
 * Attribute: Extended attribute (EA) information (0xd0).
 *
 * NOTE: Always resident. (Is this true???)
 */
typedef struct {
        le16 ea_length;         /* Byte size of the packed extended
                                   attributes. */
        le16 need_ea_count;     /* The number of extended attributes which have
                                   the NEED_EA bit set. */
        le32 ea_query_length;   /* Byte size of the buffer required to query
                                   the extended attributes when calling
                                   ZwQueryEaFile() in Windows NT/2k. I.e. the
                                   byte size of the unpacked extended
                                   attributes. */
} __attribute__ ((__packed__)) EA_INFORMATION;

/*
 * Extended attribute flags (8-bit).
 */
enum {
        NEED_EA = 0x80
} __attribute__ ((__packed__));

typedef u8 EA_FLAGS;

/*
 * Attribute: Extended attribute (EA) (0xe0).
 *
 * NOTE: Always non-resident. (Is this true?)
 *
 * Like the attribute list and the index buffer list, the EA attribute value is
 * a sequence of EA_ATTR variable length records.
 *
 * FIXME: It appears weird that the EA name is not unicode. Is it true?
 */
typedef struct {
        le32 next_entry_offset; /* Offset to the next EA_ATTR. */
        EA_FLAGS flags;         /* Flags describing the EA. */
        u8 ea_name_length;      /* Length of the name of the EA in bytes. */
        le16 ea_value_length;   /* Byte size of the EA's value. */
        u8 ea_name[0];          /* Name of the EA. */
        u8 ea_value[0];         /* The value of the EA. Immediately follows
                                   the name. */
} __attribute__ ((__packed__)) EA_ATTR;

/*
 * Attribute: Property set (0xf0).
 *
 * Intended to support Native Structure Storage (NSS) - a feature removed from
 * NTFS 3.0 during beta testing.
 */
typedef struct {
        /* Irrelevant as feature unused. */
} __attribute__ ((__packed__)) PROPERTY_SET;

/*
 * Attribute: Logged utility stream (0x100).
 *
 * NOTE: Can be resident or non-resident.
 *
 * Operations on this attribute are logged to the journal ($LogFile) like
 * normal metadata changes.
 *
 * Used by the Encrypting File System (EFS). All encrypted files have this
 * attribute with the name $EFS.
 */
typedef struct {
        /* Can be anything the creator chooses. */
        /* EFS uses it as follows: */
        // FIXME: Type this info, verifying it along the way. (AIA)
} __attribute__ ((__packed__)) LOGGED_UTILITY_STREAM, EFS_ATTR;

#endif /* _LINUX_NTFS_LAYOUT_H */