usbloadergx/source/libntfs/mft.c

/**
 * mft.c - Mft record handling code. Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2000-2004 Anton Altaparmakov
 * Copyright (c) 2004-2005 Richard Russon
 * Copyright (c) 2004-2008 Szabolcs Szakacsits
 * Copyright (c)      2005 Yura Pakhuchiy
 *
 * 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 NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#include <time.h>

#include "compat.h"
#include "types.h"
#include "device.h"
#include "debug.h"
#include "bitmap.h"
#include "attrib.h"
#include "inode.h"
#include "volume.h"
#include "layout.h"
#include "lcnalloc.h"
#include "mft.h"
#include "logging.h"
#include "misc.h"

/**
 * ntfs_mft_records_read - read records from the mft from disk
 * @vol:	volume to read from
 * @mref:	starting mft record number to read
 * @count:	number of mft records to read
 * @b:		output data buffer
 *
 * Read @count mft records starting at @mref from volume @vol into buffer
 * @b. Return 0 on success or -1 on error, with errno set to the error
 * code.
 *
 * If any of the records exceed the initialized size of the $MFT/$DATA
 * attribute, i.e. they cannot possibly be allocated mft records, assume this
 * is a bug and return error code ESPIPE.
 *
 * The read mft records are mst deprotected and are hence ready to use. The
 * caller should check each record with is_baad_record() in case mst
 * deprotection failed.
 *
 * NOTE: @b has to be at least of size @count * vol->mft_record_size.
 */
int ntfs_mft_records_read(const ntfs_volume *vol, const MFT_REF mref, const s64 count, MFT_RECORD *b)
{
    s64 br;
    VCN m;

    ntfs_log_trace("inode %llu\n", (unsigned long long)MREF(mref));

    if (!vol || !vol->mft_na || !b || count < 0)
    {
        errno = EINVAL;
        ntfs_log_perror("%s: b=%p  count=%lld  mft=%llu", __FUNCTION__,
                b, (long long)count, (unsigned long long)MREF(mref));
        return -1;
    }
    m = MREF(mref);
    /* Refuse to read non-allocated mft records. */
    if (m + count > vol->mft_na->initialized_size >> vol->mft_record_size_bits)
    {
        errno = ESPIPE;
        ntfs_log_perror("Trying to read non-allocated mft records "
                "(%lld > %lld)", (long long)m + count,
                (long long)vol->mft_na->initialized_size >>
                vol->mft_record_size_bits);
        return -1;
    }
    br = ntfs_attr_mst_pread(vol->mft_na, m << vol->mft_record_size_bits, count, vol->mft_record_size, b);
    if (br != count)
    {
        if (br != -1) errno = EIO;
        ntfs_log_perror("Failed to read of MFT, mft=%llu count=%lld "
                "br=%lld", (long long)m, (long long)count,
                (long long)br);
        return -1;
    }
    return 0;
}

/**
 * ntfs_mft_records_write - write mft records to disk
 * @vol:	volume to write to
 * @mref:	starting mft record number to write
 * @count:	number of mft records to write
 * @b:		data buffer containing the mft records to write
 *
 * Write @count mft records starting at @mref from data buffer @b to volume
 * @vol. Return 0 on success or -1 on error, with errno set to the error code.
 *
 * If any of the records exceed the initialized size of the $MFT/$DATA
 * attribute, i.e. they cannot possibly be allocated mft records, assume this
 * is a bug and return error code ESPIPE.
 *
 * Before the mft records are written, they are mst protected. After the write,
 * they are deprotected again, thus resulting in an increase in the update
 * sequence number inside the data buffer @b.
 *
 * If any mft records are written which are also represented in the mft mirror
 * $MFTMirr, we make a copy of the relevant parts of the data buffer @b into a
 * temporary buffer before we do the actual write. Then if at least one mft
 * record was successfully written, we write the appropriate mft records from
 * the copied buffer to the mft mirror, too.
 */
int ntfs_mft_records_write(const ntfs_volume *vol, const MFT_REF mref, const s64 count, MFT_RECORD *b)
{
    s64 bw;
    VCN m;
    void *bmirr = NULL;
    int cnt = 0, res = 0;

    if (!vol || !vol->mft_na || vol->mftmirr_size <= 0 || !b || count < 0)
    {
        errno = EINVAL;
        return -1;
    }
    m = MREF(mref);
    /* Refuse to write non-allocated mft records. */
    if (m + count > vol->mft_na->initialized_size >> vol->mft_record_size_bits)
    {
        errno = ESPIPE;
        ntfs_log_perror("Trying to write non-allocated mft records "
                "(%lld > %lld)", (long long)m + count,
                (long long)vol->mft_na->initialized_size >>
                vol->mft_record_size_bits);
        return -1;
    }
    if (m < vol->mftmirr_size)
    {
        if (!vol->mftmirr_na)
        {
            errno = EINVAL;
            return -1;
        }
        cnt = vol->mftmirr_size - m;
        if (cnt > count) cnt = count;
        bmirr = ntfs_malloc(cnt * vol->mft_record_size);
        if (!bmirr) return -1;
        memcpy(bmirr, b, cnt * vol->mft_record_size);
    }
    bw = ntfs_attr_mst_pwrite(vol->mft_na, m << vol->mft_record_size_bits, count, vol->mft_record_size, b);
    if (bw != count)
    {
        if (bw != -1) errno = EIO;
        if (bw >= 0)
            ntfs_log_debug("Error: partial write while writing $Mft "
                    "record(s)!\n");
        else
        ntfs_log_perror("Error writing $Mft record(s)");
        res = errno;
    }
    if (bmirr && bw > 0)
    {
        if (bw < cnt) cnt = bw;
        bw = ntfs_attr_mst_pwrite(vol->mftmirr_na, m << vol->mft_record_size_bits, cnt, vol->mft_record_size, bmirr);
        if (bw != cnt)
        {
            if (bw != -1) errno = EIO;
            ntfs_log_debug("Error: failed to sync $MFTMirr! Run "
                    "chkdsk.\n");
            res = errno;
        }
    }
    free(bmirr);
    if (!res) return res;
    errno = res;
    return -1;
}

int ntfs_mft_record_check(const ntfs_volume *vol, const MFT_REF mref, MFT_RECORD *m)
{
    ATTR_RECORD *a;
    int ret = -1;

    if (!ntfs_is_file_record(m->magic))
    {
        ntfs_log_error("Record %llu has no FILE magic (0x%x)\n",
                (unsigned long long)MREF(mref), *(le32 *)m);
        goto err_out;
    }

    if (le32_to_cpu(m->bytes_allocated) != vol->mft_record_size)
    {
        ntfs_log_error("Record %llu has corrupt allocation size "
                "(%u <> %u)\n", (unsigned long long)MREF(mref),
                vol->mft_record_size,
                le32_to_cpu(m->bytes_allocated));
        goto err_out;
    }

    a = (ATTR_RECORD *) ((char *) m + le16_to_cpu(m->attrs_offset));
    if (p2n(a) < p2n(m) || (char *) a > (char *) m + vol->mft_record_size)
    {
        ntfs_log_error("Record %llu is corrupt\n",
                (unsigned long long)MREF(mref));
        goto err_out;
    }

    ret = 0;
    err_out: if (ret) errno = EIO;
    return ret;
}

/**
 * ntfs_file_record_read - read a FILE record from the mft from disk
 * @vol:	volume to read from
 * @mref:	mft reference specifying mft record to read
 * @mrec:	address of pointer in which to return the mft record
 * @attr:	address of pointer in which to return the first attribute
 *
 * Read a FILE record from the mft of @vol from the storage medium. @mref
 * specifies the mft record to read, including the sequence number, which can
 * be 0 if no sequence number checking is to be performed.
 *
 * The function allocates a buffer large enough to hold the mft record and
 * reads the record into the buffer (mst deprotecting it in the process).
 * *@mrec is then set to point to the buffer.
 *
 * If @attr is not NULL, *@attr is set to point to the first attribute in the
 * mft record, i.e. *@attr is a pointer into *@mrec.
 *
 * Return 0 on success, or -1 on error, with errno set to the error code.
 *
 * The read mft record is checked for having the magic FILE,
 * and for having a matching sequence number (if MSEQNO(*@mref) != 0).
 * If either of these fails, -1 is returned and errno is set to EIO. If you get
 * this, but you still want to read the mft record (e.g. in order to correct
 * it), use ntfs_mft_record_read() directly.
 *
 * Note: Caller has to free *@mrec when finished.
 *
 * Note: We do not check if the mft record is flagged in use. The caller can
 *	 check if desired.
 */
int ntfs_file_record_read(const ntfs_volume *vol, const MFT_REF mref, MFT_RECORD **mrec, ATTR_RECORD **attr)
{
    MFT_RECORD *m;

    if (!vol || !mrec)
    {
        errno = EINVAL;
        ntfs_log_perror("%s: mrec=%p", __FUNCTION__, mrec);
        return -1;
    }

    m = *mrec;
    if (!m)
    {
        m = ntfs_malloc(vol->mft_record_size);
        if (!m) return -1;
    }
    if (ntfs_mft_record_read(vol, mref, m)) goto err_out;

    if (ntfs_mft_record_check(vol, mref, m)) goto err_out;

    if (MSEQNO(mref) && MSEQNO(mref) != le16_to_cpu(m->sequence_number))
    {
        ntfs_log_error("Record %llu has wrong SeqNo (%d <> %d)\n",
                (unsigned long long)MREF(mref), MSEQNO(mref),
                le16_to_cpu(m->sequence_number));
        errno = EIO;
        goto err_out;
    }
    *mrec = m;
    if (attr) *attr = (ATTR_RECORD*) ((char*) m + le16_to_cpu(m->attrs_offset));
    return 0;
    err_out: if (m != *mrec) free(m);
    return -1;
}

/**
 * ntfs_mft_record_layout - layout an mft record into a memory buffer
 * @vol:	volume to which the mft record will belong
 * @mref:	mft reference specifying the mft record number
 * @mrec:	destination buffer of size >= @vol->mft_record_size bytes
 *
 * Layout an empty, unused mft record with the mft reference @mref into the
 * buffer @m.  The volume @vol is needed because the mft record structure was
 * modified in NTFS 3.1 so we need to know which volume version this mft record
 * will be used on.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
int ntfs_mft_record_layout(const ntfs_volume *vol, const MFT_REF mref, MFT_RECORD *mrec)
{
    ATTR_RECORD *a;

    if (!vol || !mrec)
    {
        errno = EINVAL;
        ntfs_log_perror("%s: mrec=%p", __FUNCTION__, mrec);
        return -1;
    }
    /* Aligned to 2-byte boundary. */
    if (vol->major_ver < 3 || (vol->major_ver == 3 && !vol->minor_ver))
        mrec->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD_OLD) + 1) & ~1);
    else
    {
        /* Abort if mref is > 32 bits. */
        if (MREF(mref) & 0x0000ffff00000000ull)
        {
            errno = ERANGE;
            ntfs_log_perror("Mft reference exceeds 32 bits");
            return -1;
        }
        mrec->usa_ofs = cpu_to_le16((sizeof(MFT_RECORD) + 1) & ~1);
        /*
         * Set the NTFS 3.1+ specific fields while we know that the
         * volume version is 3.1+.
         */
        mrec->reserved = cpu_to_le16(0);
        mrec->mft_record_number = cpu_to_le32(MREF(mref));
    }
    mrec->magic = magic_FILE;
    if (vol->mft_record_size >= NTFS_BLOCK_SIZE)
        mrec->usa_count = cpu_to_le16(vol->mft_record_size /
                NTFS_BLOCK_SIZE + 1);
    else
    {
        mrec->usa_count = cpu_to_le16(1);
        ntfs_log_error("Sector size is bigger than MFT record size.  "
                "Setting usa_count to 1.  If Windows chkdsk "
                "reports this as corruption, please email %s "
                "stating that you saw this message and that "
                "the file system created was corrupt.  "
                "Thank you.\n", NTFS_DEV_LIST);
    }
    /* Set the update sequence number to 1. */
    *(u16*) ((u8*) mrec + le16_to_cpu(mrec->usa_ofs)) = cpu_to_le16(1);
    mrec->lsn = cpu_to_le64(0ull);
    mrec->sequence_number = cpu_to_le16(1);
    mrec->link_count = cpu_to_le16(0);
    /* Aligned to 8-byte boundary. */
    mrec->attrs_offset = cpu_to_le16((le16_to_cpu(mrec->usa_ofs) +
                    (le16_to_cpu(mrec->usa_count) << 1) + 7) & ~7);
    mrec->flags = cpu_to_le16(0);
    /*
     * Using attrs_offset plus eight bytes (for the termination attribute),
     * aligned to 8-byte boundary.
     */
    mrec->bytes_in_use = cpu_to_le32((le16_to_cpu(mrec->attrs_offset) + 8 +
                    7) & ~7);
    mrec->bytes_allocated = cpu_to_le32(vol->mft_record_size);
    mrec->base_mft_record = cpu_to_le64((MFT_REF)0);
    mrec->next_attr_instance = cpu_to_le16(0);
    a = (ATTR_RECORD*) ((u8*) mrec + le16_to_cpu(mrec->attrs_offset));
    a->type = AT_END;
    a->length = cpu_to_le32(0);
    /* Finally, clear the unused part of the mft record. */
    memset((u8*) a + 8, 0, vol->mft_record_size - ((u8*) a + 8 - (u8*) mrec));
    return 0;
}

/**
 * ntfs_mft_record_format - format an mft record on an ntfs volume
 * @vol:	volume on which to format the mft record
 * @mref:	mft reference specifying mft record to format
 *
 * Format the mft record with the mft reference @mref in $MFT/$DATA, i.e. lay
 * out an empty, unused mft record in memory and write it to the volume @vol.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
int ntfs_mft_record_format(const ntfs_volume *vol, const MFT_REF mref)
{
    MFT_RECORD *m;
    int ret = -1;

    ntfs_log_enter("Entering\n");

    m = ntfs_calloc(vol->mft_record_size);
    if (!m) goto out;

    if (ntfs_mft_record_layout(vol, mref, m)) goto free_m;

    if (ntfs_mft_record_write(vol, mref, m)) goto free_m;

    ret = 0;
    free_m: free(m);
    out:
    ntfs_log_leave("\n");
    return ret;
}

static const char *es = "  Leaving inconsistent metadata.  Run chkdsk.";

/**
 * ntfs_ffz - Find the first unset (zero) bit in a word
 * @word:
 *
 * Description...
 *
 * Returns:
 */
static inline unsigned int ntfs_ffz(unsigned int word)
{
    return ffs(~word) - 1;
}

static int ntfs_is_mft(ntfs_inode *ni)
{
    if (ni && ni->mft_no == FILE_MFT) return 1;
    return 0;
}

#ifndef PAGE_SIZE
#define PAGE_SIZE 4096
#endif

#define RESERVED_MFT_RECORDS   64

/**
 * ntfs_mft_bitmap_find_free_rec - find a free mft record in the mft bitmap
 * @vol:	volume on which to search for a free mft record
 * @base_ni:	open base inode if allocating an extent mft record or NULL
 *
 * Search for a free mft record in the mft bitmap attribute on the ntfs volume
 * @vol.
 *
 * If @base_ni is NULL start the search at the default allocator position.
 *
 * If @base_ni is not NULL start the search at the mft record after the base
 * mft record @base_ni.
 *
 * Return the free mft record on success and -1 on error with errno set to the
 * error code.  An error code of ENOSPC means that there are no free mft
 * records in the currently initialized mft bitmap.
 */
static int ntfs_mft_bitmap_find_free_rec(ntfs_volume *vol, ntfs_inode *base_ni)
{
    s64 pass_end, ll, data_pos, pass_start, ofs, bit;
    ntfs_attr *mftbmp_na;
    u8 *buf, *byte;
    unsigned int size;
    u8 pass, b;
    int ret = -1;

    ntfs_log_enter("Entering\n");

    mftbmp_na = vol->mftbmp_na;
    /*
     * Set the end of the pass making sure we do not overflow the mft
     * bitmap.
     */
    size = PAGE_SIZE;
    pass_end = vol->mft_na->allocated_size >> vol->mft_record_size_bits;
    ll = mftbmp_na->initialized_size << 3;
    if (pass_end > ll) pass_end = ll;
    pass = 1;
    if (!base_ni)
        data_pos = vol->mft_data_pos;
    else data_pos = base_ni->mft_no + 1;
    if (data_pos < RESERVED_MFT_RECORDS) data_pos = RESERVED_MFT_RECORDS;
    if (data_pos >= pass_end)
    {
        data_pos = RESERVED_MFT_RECORDS;
        pass = 2;
        /* This happens on a freshly formatted volume. */
        if (data_pos >= pass_end)
        {
            errno = ENOSPC;
            goto leave;
        }
    }
    if (ntfs_is_mft(base_ni))
    {
        data_pos = 0;
        pass = 2;
    }
    pass_start = data_pos;
    buf = ntfs_malloc(PAGE_SIZE);
    if (!buf) goto leave;

    ntfs_log_debug("Starting bitmap search: pass %u, pass_start 0x%llx, "
            "pass_end 0x%llx, data_pos 0x%llx.\n", pass,
            (long long)pass_start, (long long)pass_end,
            (long long)data_pos);
#ifdef DEBUG
    byte = NULL;
    b = 0;
#endif
    /* Loop until a free mft record is found. */
    for (; pass <= 2; size = PAGE_SIZE)
    {
        /* Cap size to pass_end. */
        ofs = data_pos >> 3;
        ll = ((pass_end + 7) >> 3) - ofs;
        if (size > ll) size = ll;
        ll = ntfs_attr_pread(mftbmp_na, ofs, size, buf);
        if (ll < 0)
        {
            ntfs_log_perror("Failed to read $MFT bitmap");
            free(buf);
            goto leave;
        }
        ntfs_log_debug("Read 0x%llx bytes.\n", (long long)ll);
        /* If we read at least one byte, search @buf for a zero bit. */
        if (ll)
        {
            size = ll << 3;
            bit = data_pos & 7;
            data_pos &= ~7ull;
            ntfs_log_debug("Before inner for loop: size 0x%x, "
                    "data_pos 0x%llx, bit 0x%llx, "
                    "*byte 0x%hhx, b %u.\n", size,
                    (long long)data_pos, (long long)bit,
                    byte ? *byte : -1, b);
            for (; bit < size && data_pos + bit < pass_end; bit &= ~7ull, bit += 8)
            {
                /*
                 * If we're extending $MFT and running out of the first
                 * mft record (base record) then give up searching since
                 * no guarantee that the found record will be accessible.
                 */
                if (ntfs_is_mft(base_ni) && bit > 400) goto out;

                byte = buf + (bit >> 3);
                if (*byte == 0xff) continue;

                /* Note: ffz() result must be zero based. */
                b = ntfs_ffz((unsigned long) *byte);
                if (b < 8 && b >= (bit & 7))
                {
                    free(buf);
                    ret = data_pos + (bit & ~7ull) + b;
                    goto leave;
                }
            }
            ntfs_log_debug("After inner for loop: size 0x%x, "
                    "data_pos 0x%llx, bit 0x%llx, "
                    "*byte 0x%hhx, b %u.\n", size,
                    (long long)data_pos, (long long)bit,
                    byte ? *byte : -1, b);
            data_pos += size;
            /*
             * If the end of the pass has not been reached yet,
             * continue searching the mft bitmap for a zero bit.
             */
            if (data_pos < pass_end) continue;
        }
        /* Do the next pass. */
        pass++;
        if (pass == 2)
        {
            /*
             * Starting the second pass, in which we scan the first
             * part of the zone which we omitted earlier.
             */
            pass_end = pass_start;
            data_pos = pass_start = RESERVED_MFT_RECORDS;
            ntfs_log_debug("pass %i, pass_start 0x%llx, pass_end "
                    "0x%llx.\n", pass, (long long)pass_start,
                    (long long)pass_end);
            if (data_pos >= pass_end) break;
        }
    }
    /* No free mft records in currently initialized mft bitmap. */
    out: free(buf);
    errno = ENOSPC;
    leave:
    ntfs_log_leave("\n");
    return ret;
}

static int ntfs_mft_attr_extend(ntfs_attr *na)
{
    int ret = STATUS_ERROR;
    ntfs_log_enter("Entering\n");

    if (!NInoAttrList(na->ni))
    {
        if (ntfs_inode_add_attrlist(na->ni))
        {
            ntfs_log_perror("%s: Can not add attrlist #3", __FUNCTION__);
            goto out;
        }
        /* We can't sync the $MFT inode since its runlist is bogus. */
        ret = STATUS_KEEP_SEARCHING;
        goto out;
    }

    if (ntfs_attr_update_mapping_pairs(na, 0))
    {
        ntfs_log_perror("%s: MP update failed", __FUNCTION__);
        goto out;
    }

    ret = STATUS_OK;
    out:
    ntfs_log_leave("\n");
    return ret;
}

/**
 * ntfs_mft_bitmap_extend_allocation_i - see ntfs_mft_bitmap_extend_allocation
 */
static int ntfs_mft_bitmap_extend_allocation_i(ntfs_volume *vol)
{
    LCN lcn;
    s64 ll = 0; /* silence compiler warning */
    ntfs_attr *mftbmp_na;
    runlist_element *rl, *rl2 = NULL; /* silence compiler warning */
    ntfs_attr_search_ctx *ctx;
    MFT_RECORD *m = NULL; /* silence compiler warning */
    ATTR_RECORD *a = NULL; /* silence compiler warning */
    int err, mp_size;
    int ret = STATUS_ERROR;
    u32 old_alen = 0; /* silence compiler warning */
    BOOL mp_rebuilt = FALSE;
    BOOL update_mp = FALSE;

    mftbmp_na = vol->mftbmp_na;
    /*
     * Determine the last lcn of the mft bitmap.  The allocated size of the
     * mft bitmap cannot be zero so we are ok to do this.
     */
    rl = ntfs_attr_find_vcn(mftbmp_na, (mftbmp_na->allocated_size - 1) >> vol->cluster_size_bits);
    if (!rl || !rl->length || rl->lcn < 0)
    {
        ntfs_log_error("Failed to determine last allocated "
                "cluster of mft bitmap attribute.\n");
        if (rl) errno = EIO;
        return STATUS_ERROR;
    }
    lcn = rl->lcn + rl->length;

    rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE);
    if (!rl2)
    {
        ntfs_log_error("Failed to allocate a cluster for "
                "the mft bitmap.\n");
        return STATUS_ERROR;
    }
    rl = ntfs_runlists_merge(mftbmp_na->rl, rl2);
    if (!rl)
    {
        err = errno;
        ntfs_log_error("Failed to merge runlists for mft "
                "bitmap.\n");
        if (ntfs_cluster_free_from_rl(vol, rl2)) ntfs_log_error("Failed to deallocate "
                "cluster.%s\n", es);
        free(rl2);
        errno = err;
        return STATUS_ERROR;
    }
    mftbmp_na->rl = rl;
    ntfs_log_debug("Adding one run to mft bitmap.\n");
    /* Find the last run in the new runlist. */
    for (; rl[1].length; rl++)
        ;
    /*
     * Update the attribute record as well.  Note: @rl is the last
     * (non-terminator) runlist element of mft bitmap.
     */
    ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
    if (!ctx) goto undo_alloc;

    if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name, mftbmp_na->name_len, 0, rl[1].vcn, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find last attribute extent of "
                "mft bitmap attribute.\n");
        goto undo_alloc;
    }
    m = ctx->mrec;
    a = ctx->attr;
    ll = sle64_to_cpu(a->lowest_vcn);
    rl2 = ntfs_attr_find_vcn(mftbmp_na, ll);
    if (!rl2 || !rl2->length)
    {
        ntfs_log_error("Failed to determine previous last "
                "allocated cluster of mft bitmap attribute.\n");
        if (rl2) errno = EIO;
        goto undo_alloc;
    }
    /* Get the size for the new mapping pairs array for this extent. */
    mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, INT_MAX);
    if (mp_size <= 0)
    {
        ntfs_log_error("Get size for mapping pairs failed for "
                "mft bitmap attribute extent.\n");
        goto undo_alloc;
    }
    /* Expand the attribute record if necessary. */
    old_alen = le32_to_cpu(a->length);
    if (ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(a->mapping_pairs_offset)))
    {
        ntfs_log_info("extending $MFT bitmap\n");
        ret = ntfs_mft_attr_extend(vol->mftbmp_na);
        if (ret == STATUS_OK) goto ok;
        if (ret == STATUS_ERROR)
        {
            ntfs_log_perror("%s: ntfs_mft_attr_extend failed", __FUNCTION__);
            update_mp = TRUE;
        }
        goto undo_alloc;
    }
    mp_rebuilt = TRUE;
    /* Generate the mapping pairs array directly into the attr record. */
    if (ntfs_mapping_pairs_build(vol, (u8*) a + le16_to_cpu(a->mapping_pairs_offset), mp_size, rl2, ll, NULL))
    {
        ntfs_log_error("Failed to build mapping pairs array for "
                "mft bitmap attribute.\n");
        errno = EIO;
        goto undo_alloc;
    }
    /* Update the highest_vcn. */
    a->highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
    /*
     * We now have extended the mft bitmap allocated_size by one cluster.
     * Reflect this in the ntfs_attr structure and the attribute record.
     */
    if (a->lowest_vcn)
    {
        /*
         * We are not in the first attribute extent, switch to it, but
         * first ensure the changes will make it to disk later.
         */
        ntfs_inode_mark_dirty(ctx->ntfs_ino);
        ntfs_attr_reinit_search_ctx(ctx);
        if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name, mftbmp_na->name_len, 0, 0, NULL, 0, ctx))
        {
            ntfs_log_error("Failed to find first attribute "
                    "extent of mft bitmap attribute.\n");
            goto restore_undo_alloc;
        }
        a = ctx->attr;
    }
    ok: mftbmp_na->allocated_size += vol->cluster_size;
    a->allocated_size = cpu_to_sle64(mftbmp_na->allocated_size);
    /* Ensure the changes make it to disk. */
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);
    return STATUS_OK;

    restore_undo_alloc: err = errno;
    ntfs_attr_reinit_search_ctx(ctx);
    if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name, mftbmp_na->name_len, 0, rl[1].vcn, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find last attribute extent of "
                "mft bitmap attribute.%s\n", es);
        ntfs_attr_put_search_ctx(ctx);
        mftbmp_na->allocated_size += vol->cluster_size;
        /*
         * The only thing that is now wrong is ->allocated_size of the
         * base attribute extent which chkdsk should be able to fix.
         */
        errno = err;
        return STATUS_ERROR;
    }
    m = ctx->mrec;
    a = ctx->attr;
    a->highest_vcn = cpu_to_sle64(rl[1].vcn - 2);
    errno = err;
    undo_alloc: err = errno;

    /* Remove the last run from the runlist. */
    lcn = rl->lcn;
    rl->lcn = rl[1].lcn;
    rl->length = 0;

    /* FIXME: use an ntfs_cluster_free_* function */
    if (ntfs_bitmap_clear_bit(vol->lcnbmp_na, lcn))
        ntfs_log_error("Failed to free cluster.%s\n", es);
    else vol->free_clusters++;
    if (mp_rebuilt)
    {
        if (ntfs_mapping_pairs_build(vol, (u8*) a + le16_to_cpu(a->mapping_pairs_offset), old_alen
                - le16_to_cpu(a->mapping_pairs_offset), rl2, ll, NULL)) ntfs_log_error("Failed to restore mapping "
                "pairs array.%s\n", es);
        if (ntfs_attr_record_resize(m, a, old_alen)) ntfs_log_error("Failed to restore attribute "
                "record.%s\n", es);
        ntfs_inode_mark_dirty(ctx->ntfs_ino);
    }
    if (update_mp)
    {
        if (ntfs_attr_update_mapping_pairs(vol->mftbmp_na, 0)) ntfs_log_perror("%s: MP update failed", __FUNCTION__);
    }
    if (ctx) ntfs_attr_put_search_ctx(ctx);
    errno = err;
    return ret;
}

/**
 * ntfs_mft_bitmap_extend_allocation - extend mft bitmap attribute by a cluster
 * @vol:	volume on which to extend the mft bitmap attribute
 *
 * Extend the mft bitmap attribute on the ntfs volume @vol by one cluster.
 *
 * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
 * data_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_bitmap_extend_allocation(ntfs_volume *vol)
{
    int ret;

    ntfs_log_enter("Entering\n");
    ret = ntfs_mft_bitmap_extend_allocation_i(vol);
    ntfs_log_leave("\n");
    return ret;
}
/**
 * ntfs_mft_bitmap_extend_initialized - extend mft bitmap initialized data
 * @vol:	volume on which to extend the mft bitmap attribute
 *
 * Extend the initialized portion of the mft bitmap attribute on the ntfs
 * volume @vol by 8 bytes.
 *
 * Note:  Only changes initialized_size and data_size, i.e. requires that
 * allocated_size is big enough to fit the new initialized_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_bitmap_extend_initialized(ntfs_volume *vol)
{
    s64 old_data_size, old_initialized_size, ll;
    ntfs_attr *mftbmp_na;
    ntfs_attr_search_ctx *ctx;
    ATTR_RECORD *a;
    int err;
    int ret = -1;

    ntfs_log_enter("Entering\n");

    mftbmp_na = vol->mftbmp_na;
    ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
    if (!ctx) goto out;

    if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name, mftbmp_na->name_len, 0, 0, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find first attribute extent of "
                "mft bitmap attribute.\n");
        err = errno;
        goto put_err_out;
    }
    a = ctx->attr;
    old_data_size = mftbmp_na->data_size;
    old_initialized_size = mftbmp_na->initialized_size;
    mftbmp_na->initialized_size += 8;
    a->initialized_size = cpu_to_sle64(mftbmp_na->initialized_size);
    if (mftbmp_na->initialized_size > mftbmp_na->data_size)
    {
        mftbmp_na->data_size = mftbmp_na->initialized_size;
        a->data_size = cpu_to_sle64(mftbmp_na->data_size);
    }
    /* Ensure the changes make it to disk. */
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);
    /* Initialize the mft bitmap attribute value with zeroes. */
    ll = 0;
    ll = ntfs_attr_pwrite(mftbmp_na, old_initialized_size, 8, &ll);
    if (ll == 8)
    {
        ntfs_log_debug("Wrote eight initialized bytes to mft bitmap.\n");
        vol->free_mft_records += (8 * 8);
        ret = 0;
        goto out;
    }
    ntfs_log_error("Failed to write to mft bitmap.\n");
    err = errno;
    if (ll >= 0) err = EIO;
    /* Try to recover from the error. */
    ctx = ntfs_attr_get_search_ctx(mftbmp_na->ni, NULL);
    if (!ctx) goto err_out;

    if (ntfs_attr_lookup(mftbmp_na->type, mftbmp_na->name, mftbmp_na->name_len, 0, 0, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find first attribute extent of "
                "mft bitmap attribute.%s\n", es);
        put_err_out: ntfs_attr_put_search_ctx(ctx);
        goto err_out;
    }
    a = ctx->attr;
    mftbmp_na->initialized_size = old_initialized_size;
    a->initialized_size = cpu_to_sle64(old_initialized_size);
    if (mftbmp_na->data_size != old_data_size)
    {
        mftbmp_na->data_size = old_data_size;
        a->data_size = cpu_to_sle64(old_data_size);
    }
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);
    ntfs_log_debug("Restored status of mftbmp: allocated_size 0x%llx, "
            "data_size 0x%llx, initialized_size 0x%llx.\n",
            (long long)mftbmp_na->allocated_size,
            (long long)mftbmp_na->data_size,
            (long long)mftbmp_na->initialized_size);
    err_out: errno = err;
    out:
    ntfs_log_leave("\n");
    return ret;
}

/**
 * ntfs_mft_data_extend_allocation - extend mft data attribute
 * @vol:	volume on which to extend the mft data attribute
 *
 * Extend the mft data attribute on the ntfs volume @vol by 16 mft records
 * worth of clusters or if not enough space for this by one mft record worth
 * of clusters.
 *
 * Note:  Only changes allocated_size, i.e. does not touch initialized_size or
 * data_size.
 *
 * Return 0 on success and -1 on error with errno set to the error code.
 */
static int ntfs_mft_data_extend_allocation(ntfs_volume *vol)
{
    LCN lcn;
    VCN old_last_vcn;
    s64 min_nr, nr, ll = 0; /* silence compiler warning */
    ntfs_attr *mft_na;
    runlist_element *rl, *rl2;
    ntfs_attr_search_ctx *ctx;
    MFT_RECORD *m = NULL; /* silence compiler warning */
    ATTR_RECORD *a = NULL; /* silence compiler warning */
    int err, mp_size;
    int ret = STATUS_ERROR;
    u32 old_alen = 0; /* silence compiler warning */
    BOOL mp_rebuilt = FALSE;
    BOOL update_mp = FALSE;

    ntfs_log_enter("Extending mft data allocation.\n");

    mft_na = vol->mft_na;
    /*
     * Determine the preferred allocation location, i.e. the last lcn of
     * the mft data attribute.  The allocated size of the mft data
     * attribute cannot be zero so we are ok to do this.
     */
    rl = ntfs_attr_find_vcn(mft_na, (mft_na->allocated_size - 1) >> vol->cluster_size_bits);

    if (!rl || !rl->length || rl->lcn < 0)
    {
        ntfs_log_error("Failed to determine last allocated "
                "cluster of mft data attribute.\n");
        if (rl) errno = EIO;
        goto out;
    }

    lcn = rl->lcn + rl->length;
    ntfs_log_debug("Last lcn of mft data attribute is 0x%llx.\n", (long long)lcn);
    /* Minimum allocation is one mft record worth of clusters. */
    min_nr = vol->mft_record_size >> vol->cluster_size_bits;
    if (!min_nr) min_nr = 1;
    /* Want to allocate 16 mft records worth of clusters. */
    nr = vol->mft_record_size << 4 >> vol->cluster_size_bits;
    if (!nr) nr = min_nr;

    old_last_vcn = rl[1].vcn;
    do
    {
        rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE);
        if (rl2) break;
        if (errno != ENOSPC || nr == min_nr)
        {
            ntfs_log_perror("Failed to allocate (%lld) clusters "
                    "for $MFT", (long long)nr);
            goto out;
        }
        /*
         * There is not enough space to do the allocation, but there
         * might be enough space to do a minimal allocation so try that
         * before failing.
         */
        nr = min_nr;
        ntfs_log_debug("Retrying mft data allocation with minimal cluster "
                "count %lli.\n", (long long)nr);
    } while (1);

    ntfs_log_debug("Allocated %lld clusters.\n", (long long)nr);

    rl = ntfs_runlists_merge(mft_na->rl, rl2);
    if (!rl)
    {
        err = errno;
        ntfs_log_error("Failed to merge runlists for mft data "
                "attribute.\n");
        if (ntfs_cluster_free_from_rl(vol, rl2)) ntfs_log_error("Failed to deallocate clusters "
                "from the mft data attribute.%s\n", es);
        free(rl2);
        errno = err;
        goto out;
    }
    mft_na->rl = rl;

    /* Find the last run in the new runlist. */
    for (; rl[1].length; rl++)
        ;
    /* Update the attribute record as well. */
    ctx = ntfs_attr_get_search_ctx(mft_na->ni, NULL);
    if (!ctx) goto undo_alloc;

    if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0, rl[1].vcn, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find last attribute extent of "
                "mft data attribute.\n");
        goto undo_alloc;
    }
    m = ctx->mrec;
    a = ctx->attr;
    ll = sle64_to_cpu(a->lowest_vcn);
    rl2 = ntfs_attr_find_vcn(mft_na, ll);
    if (!rl2 || !rl2->length)
    {
        ntfs_log_error("Failed to determine previous last "
                "allocated cluster of mft data attribute.\n");
        if (rl2) errno = EIO;
        goto undo_alloc;
    }
    /* Get the size for the new mapping pairs array for this extent. */
    mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, INT_MAX);
    if (mp_size <= 0)
    {
        ntfs_log_error("Get size for mapping pairs failed for "
                "mft data attribute extent.\n");
        goto undo_alloc;
    }
    /* Expand the attribute record if necessary. */
    old_alen = le32_to_cpu(a->length);
    if (ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(a->mapping_pairs_offset)))
    {
        ret = ntfs_mft_attr_extend(vol->mft_na);
        if (ret == STATUS_OK) goto ok;
        if (ret == STATUS_ERROR)
        {
            ntfs_log_perror("%s: ntfs_mft_attr_extend failed", __FUNCTION__);
            update_mp = TRUE;
        }
        goto undo_alloc;
    }
    mp_rebuilt = TRUE;
    /*
     * Generate the mapping pairs array directly into the attribute record.
     */
    if (ntfs_mapping_pairs_build(vol, (u8*) a + le16_to_cpu(a->mapping_pairs_offset), mp_size, rl2, ll, NULL))
    {
        ntfs_log_error("Failed to build mapping pairs array of "
                "mft data attribute.\n");
        errno = EIO;
        goto undo_alloc;
    }
    /* Update the highest_vcn. */
    a->highest_vcn = cpu_to_sle64(rl[1].vcn - 1);
    /*
     * We now have extended the mft data allocated_size by nr clusters.
     * Reflect this in the ntfs_attr structure and the attribute record.
     * @rl is the last (non-terminator) runlist element of mft data
     * attribute.
     */
    if (a->lowest_vcn)
    {
        /*
         * We are not in the first attribute extent, switch to it, but
         * first ensure the changes will make it to disk later.
         */
        ntfs_inode_mark_dirty(ctx->ntfs_ino);
        ntfs_attr_reinit_search_ctx(ctx);
        if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0, 0, NULL, 0, ctx))
        {
            ntfs_log_error("Failed to find first attribute "
                    "extent of mft data attribute.\n");
            goto restore_undo_alloc;
        }
        a = ctx->attr;
    }
    ok: mft_na->allocated_size += nr << vol->cluster_size_bits;
    a->allocated_size = cpu_to_sle64(mft_na->allocated_size);
    /* Ensure the changes make it to disk. */
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);
    ret = STATUS_OK;
    out:
    ntfs_log_leave("\n");
    return ret;

    restore_undo_alloc: err = errno;
    ntfs_attr_reinit_search_ctx(ctx);
    if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0, rl[1].vcn, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find last attribute extent of "
                "mft data attribute.%s\n", es);
        ntfs_attr_put_search_ctx(ctx);
        mft_na->allocated_size += nr << vol->cluster_size_bits;
        /*
         * The only thing that is now wrong is ->allocated_size of the
         * base attribute extent which chkdsk should be able to fix.
         */
        errno = err;
        ret = STATUS_ERROR;
        goto out;
    }
    m = ctx->mrec;
    a = ctx->attr;
    a->highest_vcn = cpu_to_sle64(old_last_vcn - 1);
    errno = err;
    undo_alloc: err = errno;
    if (ntfs_cluster_free(vol, mft_na, old_last_vcn, -1) < 0) ntfs_log_error("Failed to free clusters from mft data "
            "attribute.%s\n", es);
    if (ntfs_rl_truncate(&mft_na->rl, old_last_vcn)) ntfs_log_error("Failed to truncate mft data attribute "
            "runlist.%s\n", es);
    if (mp_rebuilt)
    {
        if (ntfs_mapping_pairs_build(vol, (u8*) a + le16_to_cpu(a->mapping_pairs_offset), old_alen
                - le16_to_cpu(a->mapping_pairs_offset), rl2, ll, NULL)) ntfs_log_error("Failed to restore mapping pairs "
                "array.%s\n", es);
        if (ntfs_attr_record_resize(m, a, old_alen)) ntfs_log_error("Failed to restore attribute "
                "record.%s\n", es);
        ntfs_inode_mark_dirty(ctx->ntfs_ino);
    }
    if (update_mp)
    {
        if (ntfs_attr_update_mapping_pairs(vol->mft_na, 0)) ntfs_log_perror("%s: MP update failed", __FUNCTION__);
    }
    if (ctx) ntfs_attr_put_search_ctx(ctx);
    errno = err;
    goto out;
}

static int ntfs_mft_record_init(ntfs_volume *vol, s64 size)
{
    int ret = -1;
    ntfs_attr *mft_na, *mftbmp_na;
    s64 old_data_initialized, old_data_size;
    ntfs_attr_search_ctx *ctx;

    ntfs_log_enter("Entering\n");

    /* NOTE: Caller must sanity check vol, vol->mft_na and vol->mftbmp_na */

    mft_na = vol->mft_na;
    mftbmp_na = vol->mftbmp_na;

    /*
     * The mft record is outside the initialized data. Extend the mft data
     * attribute until it covers the allocated record. The loop is only
     * actually traversed more than once when a freshly formatted volume
     * is first written to so it optimizes away nicely in the common case.
     */
    ntfs_log_debug("Status of mft data before extension: "
            "allocated_size 0x%llx, data_size 0x%llx, "
            "initialized_size 0x%llx.\n",
            (long long)mft_na->allocated_size,
            (long long)mft_na->data_size,
            (long long)mft_na->initialized_size);
    while (size > mft_na->allocated_size)
    {
        if (ntfs_mft_data_extend_allocation(vol) == STATUS_ERROR) goto out;
        ntfs_log_debug("Status of mft data after allocation extension: "
                "allocated_size 0x%llx, data_size 0x%llx, "
                "initialized_size 0x%llx.\n",
                (long long)mft_na->allocated_size,
                (long long)mft_na->data_size,
                (long long)mft_na->initialized_size);
    }

    old_data_initialized = mft_na->initialized_size;
    old_data_size = mft_na->data_size;

    /*
     * Extend mft data initialized size (and data size of course) to reach
     * the allocated mft record, formatting the mft records along the way.
     * Note: We only modify the ntfs_attr structure as that is all that is
     * needed by ntfs_mft_record_format().  We will update the attribute
     * record itself in one fell swoop later on.
     */
    while (size > mft_na->initialized_size)
    {
        s64 ll2 = mft_na->initialized_size >> vol->mft_record_size_bits;
        mft_na->initialized_size += vol->mft_record_size;
        if (mft_na->initialized_size > mft_na->data_size) mft_na->data_size = mft_na->initialized_size;
        ntfs_log_debug("Initializing mft record 0x%llx.\n", (long long)ll2);
        if (ntfs_mft_record_format(vol, ll2) < 0)
        {
            ntfs_log_perror("Failed to format mft record");
            goto undo_data_init;
        }
    }

    /* Update the mft data attribute record to reflect the new sizes. */
    ctx = ntfs_attr_get_search_ctx(mft_na->ni, NULL);
    if (!ctx) goto undo_data_init;

    if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0, 0, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find first attribute extent of "
                "mft data attribute.\n");
        ntfs_attr_put_search_ctx(ctx);
        goto undo_data_init;
    }
    ctx->attr->initialized_size = cpu_to_sle64(mft_na->initialized_size);
    ctx->attr->data_size = cpu_to_sle64(mft_na->data_size);
    ctx->attr->allocated_size = cpu_to_sle64(mft_na->allocated_size);

    /* Ensure the changes make it to disk. */
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);
    ntfs_log_debug("Status of mft data after mft record initialization: "
            "allocated_size 0x%llx, data_size 0x%llx, "
            "initialized_size 0x%llx.\n",
            (long long)mft_na->allocated_size,
            (long long)mft_na->data_size,
            (long long)mft_na->initialized_size);

    /* Sanity checks. */
    if (mft_na->data_size > mft_na->allocated_size || mft_na->initialized_size > mft_na->data_size)
    NTFS_BUG("mft_na sanity checks failed");

    /* Sync MFT to minimize data loss if there won't be clean unmount. */
    if (ntfs_inode_sync(mft_na->ni)) goto undo_data_init;

    ret = 0;
    out:
    ntfs_log_leave("\n");
    return ret;

    undo_data_init: mft_na->initialized_size = old_data_initialized;
    mft_na->data_size = old_data_size;
    goto out;
}

static int ntfs_mft_rec_init(ntfs_volume *vol, s64 size)
{
    int ret = -1;
    ntfs_attr *mft_na, *mftbmp_na;
    s64 old_data_initialized, old_data_size;
    ntfs_attr_search_ctx *ctx;

    ntfs_log_enter("Entering\n");

    mft_na = vol->mft_na;
    mftbmp_na = vol->mftbmp_na;

    if (size > mft_na->allocated_size || size > mft_na->initialized_size)
    {
        errno = EIO;
        ntfs_log_perror("%s: unexpected $MFT sizes, see below", __FUNCTION__);
        ntfs_log_error("$MFT: size=%lld  allocated_size=%lld  "
                "data_size=%lld  initialized_size=%lld\n",
                (long long)size,
                (long long)mft_na->allocated_size,
                (long long)mft_na->data_size,
                (long long)mft_na->initialized_size);
        goto out;
    }

    old_data_initialized = mft_na->initialized_size;
    old_data_size = mft_na->data_size;

    /* Update the mft data attribute record to reflect the new sizes. */
    ctx = ntfs_attr_get_search_ctx(mft_na->ni, NULL);
    if (!ctx) goto undo_data_init;

    if (ntfs_attr_lookup(mft_na->type, mft_na->name, mft_na->name_len, 0, 0, NULL, 0, ctx))
    {
        ntfs_log_error("Failed to find first attribute extent of "
                "mft data attribute.\n");
        ntfs_attr_put_search_ctx(ctx);
        goto undo_data_init;
    }
    ctx->attr->initialized_size = cpu_to_sle64(mft_na->initialized_size);
    ctx->attr->data_size = cpu_to_sle64(mft_na->data_size);

    /* CHECKME: ctx->attr->allocation_size is already ok? */

    /* Ensure the changes make it to disk. */
    ntfs_inode_mark_dirty(ctx->ntfs_ino);
    ntfs_attr_put_search_ctx(ctx);

    /* Sanity checks. */
    if (mft_na->data_size > mft_na->allocated_size || mft_na->initialized_size > mft_na->data_size)
    NTFS_BUG("mft_na sanity checks failed");
    out:
    ntfs_log_leave("\n");
    return ret;

    undo_data_init: mft_na->initialized_size = old_data_initialized;
    mft_na->data_size = old_data_size;
    goto out;
}

static ntfs_inode *ntfs_mft_rec_alloc(ntfs_volume *vol)
{
    s64 ll, bit;
    ntfs_attr *mft_na, *mftbmp_na;
    MFT_RECORD *m;
    ntfs_inode *ni = NULL;
    ntfs_inode *base_ni;
    int err;
    le16 seq_no, usn;

    ntfs_log_enter("Entering\n");

    mft_na = vol->mft_na;
    mftbmp_na = vol->mftbmp_na;

    base_ni = mft_na->ni;

    bit = ntfs_mft_bitmap_find_free_rec(vol, base_ni);
    if (bit >= 0) goto found_free_rec;

    if (errno != ENOSPC) goto out;

    errno = ENOSPC;
    /* strerror() is intentionally used below, we want to log this error. */
    ntfs_log_error("No free mft record for $MFT: %s\n", strerror(errno));
    goto err_out;

    found_free_rec: if (ntfs_bitmap_set_bit(mftbmp_na, bit))
    {
        ntfs_log_error("Failed to allocate bit in mft bitmap #2\n");
        goto err_out;
    }

    ll = (bit + 1) << vol->mft_record_size_bits;
    if (ll > mft_na->initialized_size) if (ntfs_mft_rec_init(vol, ll) < 0) goto undo_mftbmp_alloc;
    /*
     * We now have allocated and initialized the mft record.  Need to read
     * it from disk and re-format it, preserving the sequence number if it
     * is not zero as well as the update sequence number if it is not zero
     * or -1 (0xffff).
     */
    m = ntfs_malloc(vol->mft_record_size);
    if (!m) goto undo_mftbmp_alloc;

    if (ntfs_mft_record_read(vol, bit, m))
    {
        free(m);
        goto undo_mftbmp_alloc;
    }
    /* Sanity check that the mft record is really not in use. */
    if (ntfs_is_file_record(m->magic) && (m->flags & MFT_RECORD_IN_USE))
    {
        ntfs_log_error("Inode %lld is used but it wasn't marked in "
                "$MFT bitmap. Fixed.\n", (long long)bit);
        free(m);
        goto undo_mftbmp_alloc;
    }

    seq_no = m->sequence_number;
    usn = *(le16*) ((u8*) m + le16_to_cpu(m->usa_ofs));
    if (ntfs_mft_record_layout(vol, bit, m))
    {
        ntfs_log_error("Failed to re-format mft record.\n");
        free(m);
        goto undo_mftbmp_alloc;
    }
    if (seq_no) m->sequence_number = seq_no;
    seq_no = usn;
    if (seq_no && seq_no != const_cpu_to_le16(0xffff)) *(le16*) ((u8*) m + le16_to_cpu(m->usa_ofs)) = usn;
    /* Set the mft record itself in use. */
    m->flags |= MFT_RECORD_IN_USE;
    /* Now need to open an ntfs inode for the mft record. */
    ni = ntfs_inode_allocate(vol);
    if (!ni)
    {
        ntfs_log_error("Failed to allocate buffer for inode.\n");
        free(m);
        goto undo_mftbmp_alloc;
    }
    ni->mft_no = bit;
    ni->mrec = m;
    /*
     * If we are allocating an extent mft record, make the opened inode an
     * extent inode and attach it to the base inode.  Also, set the base
     * mft record reference in the extent inode.
     */
    ni->nr_extents = -1;
    ni->base_ni = base_ni;
    m->base_mft_record = MK_LE_MREF(base_ni->mft_no,
            le16_to_cpu(base_ni->mrec->sequence_number));
    /*
     * Attach the extent inode to the base inode, reallocating
     * memory if needed.
     */
    if (!(base_ni->nr_extents & 3))
    {
        ntfs_inode **extent_nis;
        int i;

        i = (base_ni->nr_extents + 4) * sizeof(ntfs_inode *);
        extent_nis = ntfs_malloc(i);
        if (!extent_nis)
        {
            free(m);
            free(ni);
            goto undo_mftbmp_alloc;
        }
        if (base_ni->nr_extents)
        {
            memcpy(extent_nis, base_ni->extent_nis, i - 4 * sizeof(ntfs_inode *));
            free(base_ni->extent_nis);
        }
        base_ni->extent_nis = extent_nis;
    }
    base_ni->extent_nis[base_ni->nr_extents++] = ni;

    /* Make sure the allocated inode is written out to disk later. */
    ntfs_inode_mark_dirty(ni);
    /* Initialize time, allocated and data size in ntfs_inode struct. */
    ni->data_size = ni->allocated_size = 0;
    ni->flags = 0;
    ni->creation_time = ni->last_data_change_time = ni->last_mft_change_time = ni->last_access_time
            = ntfs_current_time();
    /* Update the default mft allocation position if it was used. */
    if (!base_ni) vol->mft_data_pos = bit + 1;
    /* Return the opened, allocated inode of the allocated mft record. */
    ntfs_log_error("allocated %sinode %lld\n",
            base_ni ? "extent " : "", (long long)bit);
    out:
    ntfs_log_leave("\n");
    return ni;

    undo_mftbmp_alloc: err = errno;
    if (ntfs_bitmap_clear_bit(mftbmp_na, bit)) ntfs_log_error("Failed to clear bit in mft bitmap.%s\n", es);
    errno = err;
    err_out: if (!errno) errno = EIO;
    ni = NULL;
    goto out;
}

/**
 * ntfs_mft_record_alloc - allocate an mft record on an ntfs volume
 * @vol:	volume on which to allocate the mft record
 * @base_ni:	open base inode if allocating an extent mft record or NULL
 *
 * Allocate an mft record in $MFT/$DATA of an open ntfs volume @vol.
 *
 * If @base_ni is NULL make the mft record a base mft record and allocate it at
 * the default allocator position.
 *
 * If @base_ni is not NULL make the allocated mft record an extent record,
 * allocate it starting at the mft record after the base mft record and attach
 * the allocated and opened ntfs inode to the base inode @base_ni.
 *
 * On success return the now opened ntfs (extent) inode of the mft record.
 *
 * On error return NULL with errno set to the error code.
 *
 * To find a free mft record, we scan the mft bitmap for a zero bit.  To
 * optimize this we start scanning at the place specified by @base_ni or if
 * @base_ni is NULL we start where we last stopped and we perform wrap around
 * when we reach the end.  Note, we do not try to allocate mft records below
 * number 24 because numbers 0 to 15 are the defined system files anyway and 16
 * to 24 are special in that they are used for storing extension mft records
 * for the $DATA attribute of $MFT.  This is required to avoid the possibility
 * of creating a run list with a circular dependence which once written to disk
 * can never be read in again.  Windows will only use records 16 to 24 for
 * normal files if the volume is completely out of space.  We never use them
 * which means that when the volume is really out of space we cannot create any
 * more files while Windows can still create up to 8 small files.  We can start
 * doing this at some later time, it does not matter much for now.
 *
 * When scanning the mft bitmap, we only search up to the last allocated mft
 * record.  If there are no free records left in the range 24 to number of
 * allocated mft records, then we extend the $MFT/$DATA attribute in order to
 * create free mft records.  We extend the allocated size of $MFT/$DATA by 16
 * records at a time or one cluster, if cluster size is above 16kiB.  If there
 * is not sufficient space to do this, we try to extend by a single mft record
 * or one cluster, if cluster size is above the mft record size, but we only do
 * this if there is enough free space, which we know from the values returned
 * by the failed cluster allocation function when we tried to do the first
 * allocation.
 *
 * No matter how many mft records we allocate, we initialize only the first
 * allocated mft record, incrementing mft data size and initialized size
 * accordingly, open an ntfs_inode for it and return it to the caller, unless
 * there are less than 24 mft records, in which case we allocate and initialize
 * mft records until we reach record 24 which we consider as the first free mft
 * record for use by normal files.
 *
 * If during any stage we overflow the initialized data in the mft bitmap, we
 * extend the initialized size (and data size) by 8 bytes, allocating another
 * cluster if required.  The bitmap data size has to be at least equal to the
 * number of mft records in the mft, but it can be bigger, in which case the
 * superfluous bits are padded with zeroes.
 *
 * Thus, when we return successfully (return value non-zero), we will have:
 *	- initialized / extended the mft bitmap if necessary,
 *	- initialized / extended the mft data if necessary,
 *	- set the bit corresponding to the mft record being allocated in the
 *	  mft bitmap,
 *	- open an ntfs_inode for the allocated mft record, and we will
 *	- return the ntfs_inode.
 *
 * On error (return value zero), nothing will have changed.  If we had changed
 * anything before the error occurred, we will have reverted back to the
 * starting state before returning to the caller.  Thus, except for bugs, we
 * should always leave the volume in a consistent state when returning from
 * this function.
 *
 * Note, this function cannot make use of most of the normal functions, like
 * for example for attribute resizing, etc, because when the run list overflows
 * the base mft record and an attribute list is used, it is very important that
 * the extension mft records used to store the $DATA attribute of $MFT can be
 * reached without having to read the information contained inside them, as
 * this would make it impossible to find them in the first place after the
 * volume is dismounted.  $MFT/$BITMAP probably does not need to follow this
 * rule because the bitmap is not essential for finding the mft records, but on
 * the other hand, handling the bitmap in this special way would make life
 * easier because otherwise there might be circular invocations of functions
 * when reading the bitmap but if we are careful, we should be able to avoid
 * all problems.
 */
ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, ntfs_inode *base_ni)
{
    s64 ll, bit;
    ntfs_attr *mft_na, *mftbmp_na;
    MFT_RECORD *m;
    ntfs_inode *ni = NULL;
    int err;
    le16 seq_no, usn;

    if (base_ni)
        ntfs_log_enter("Entering (allocating an extent mft record for "
                "base mft record %lld).\n",
                (long long)base_ni->mft_no);
else    ntfs_log_enter("Entering (allocating a base mft record)\n");
    if (!vol || !vol->mft_na || !vol->mftbmp_na)
    {
        errno = EINVAL;
        goto out;
    }

    if (ntfs_is_mft(base_ni))
    {
        ni = ntfs_mft_rec_alloc(vol);
        goto out;
    }

    mft_na = vol->mft_na;
    mftbmp_na = vol->mftbmp_na;
    retry:
    bit = ntfs_mft_bitmap_find_free_rec(vol, base_ni);
    if (bit >= 0)
    {
        ntfs_log_debug("found free record (#1) at %lld\n",
                (long long)bit);
        goto found_free_rec;
    }
    if (errno != ENOSPC)
    goto out;
    /*
     * No free mft records left.  If the mft bitmap already covers more
     * than the currently used mft records, the next records are all free,
     * so we can simply allocate the first unused mft record.
     * Note: We also have to make sure that the mft bitmap at least covers
     * the first 24 mft records as they are special and whilst they may not
     * be in use, we do not allocate from them.
     */
    ll = mft_na->initialized_size >> vol->mft_record_size_bits;
    if (mftbmp_na->initialized_size << 3 > ll &&
            mftbmp_na->initialized_size > RESERVED_MFT_RECORDS / 8)
    {
        bit = ll;
        if (bit < RESERVED_MFT_RECORDS)
        bit = RESERVED_MFT_RECORDS;
        ntfs_log_debug("found free record (#2) at %lld\n",
                (long long)bit);
        goto found_free_rec;
    }
    /*
     * The mft bitmap needs to be expanded until it covers the first unused
     * mft record that we can allocate.
     * Note: The smallest mft record we allocate is mft record 24.
     */
    ntfs_log_debug("Status of mftbmp before extension: allocated_size 0x%llx, "
            "data_size 0x%llx, initialized_size 0x%llx.\n",
            (long long)mftbmp_na->allocated_size,
            (long long)mftbmp_na->data_size,
            (long long)mftbmp_na->initialized_size);
    if (mftbmp_na->initialized_size + 8 > mftbmp_na->allocated_size)
    {

        int ret = ntfs_mft_bitmap_extend_allocation(vol);

        if (ret == STATUS_ERROR)
        goto err_out;
        if (ret == STATUS_KEEP_SEARCHING)
        {
            ret = ntfs_mft_bitmap_extend_allocation(vol);
            if (ret != STATUS_OK)
            goto err_out;
        }

        ntfs_log_debug("Status of mftbmp after allocation extension: "
                "allocated_size 0x%llx, data_size 0x%llx, "
                "initialized_size 0x%llx.\n",
                (long long)mftbmp_na->allocated_size,
                (long long)mftbmp_na->data_size,
                (long long)mftbmp_na->initialized_size);
    }
    /*
     * We now have sufficient allocated space, extend the initialized_size
     * as well as the data_size if necessary and fill the new space with
     * zeroes.
     */
    bit = mftbmp_na->initialized_size << 3;
    if (ntfs_mft_bitmap_extend_initialized(vol))
    goto err_out;
    ntfs_log_debug("Status of mftbmp after initialized extension: "
            "allocated_size 0x%llx, data_size 0x%llx, "
            "initialized_size 0x%llx.\n",
            (long long)mftbmp_na->allocated_size,
            (long long)mftbmp_na->data_size,
            (long long)mftbmp_na->initialized_size);
    ntfs_log_debug("found free record (#3) at %lld\n", (long long)bit);
    found_free_rec:
    /* @bit is the found free mft record, allocate it in the mft bitmap. */
    if (ntfs_bitmap_set_bit(mftbmp_na, bit))
    {
        ntfs_log_error("Failed to allocate bit in mft bitmap.\n");
        goto err_out;
    }

    /* The mft bitmap is now uptodate.  Deal with mft data attribute now. */
    ll = (bit + 1) << vol->mft_record_size_bits;
    if (ll > mft_na->initialized_size)
    if (ntfs_mft_record_init(vol, ll) < 0)
    goto undo_mftbmp_alloc;

    /*
     * We now have allocated and initialized the mft record.  Need to read
     * it from disk and re-format it, preserving the sequence number if it
     * is not zero as well as the update sequence number if it is not zero
     * or -1 (0xffff).
     */
    m = ntfs_malloc(vol->mft_record_size);
    if (!m)
    goto undo_mftbmp_alloc;

    if (ntfs_mft_record_read(vol, bit, m))
    {
        free(m);
        goto undo_mftbmp_alloc;
    }
    /* Sanity check that the mft record is really not in use. */
    if (ntfs_is_file_record(m->magic) && (m->flags & MFT_RECORD_IN_USE))
    {
        ntfs_log_error("Inode %lld is used but it wasn't marked in "
                "$MFT bitmap. Fixed.\n", (long long)bit);
        free(m);
        goto retry;
    }
    seq_no = m->sequence_number;
    usn = *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs));
    if (ntfs_mft_record_layout(vol, bit, m))
    {
        ntfs_log_error("Failed to re-format mft record.\n");
        free(m);
        goto undo_mftbmp_alloc;
    }
    if (seq_no)
    m->sequence_number = seq_no;
    seq_no = usn;
    if (seq_no && seq_no != const_cpu_to_le16(0xffff))
    *(le16*)((u8*)m + le16_to_cpu(m->usa_ofs)) = usn;
    /* Set the mft record itself in use. */
    m->flags |= MFT_RECORD_IN_USE;
    /* Now need to open an ntfs inode for the mft record. */
    ni = ntfs_inode_allocate(vol);
    if (!ni)
    {
        ntfs_log_error("Failed to allocate buffer for inode.\n");
        free(m);
        goto undo_mftbmp_alloc;
    }
    ni->mft_no = bit;
    ni->mrec = m;
    /*
     * If we are allocating an extent mft record, make the opened inode an
     * extent inode and attach it to the base inode.  Also, set the base
     * mft record reference in the extent inode.
     */
    if (base_ni)
    {
        ni->nr_extents = -1;
        ni->base_ni = base_ni;
        m->base_mft_record = MK_LE_MREF(base_ni->mft_no,
                le16_to_cpu(base_ni->mrec->sequence_number));
        /*
         * Attach the extent inode to the base inode, reallocating
         * memory if needed.
         */
        if (!(base_ni->nr_extents & 3))
        {
            ntfs_inode **extent_nis;
            int i;

            i = (base_ni->nr_extents + 4) * sizeof(ntfs_inode *);
            extent_nis = ntfs_malloc(i);
            if (!extent_nis)
            {
                free(m);
                free(ni);
                goto undo_mftbmp_alloc;
            }
            if (base_ni->nr_extents)
            {
                memcpy(extent_nis, base_ni->extent_nis,
                        i - 4 * sizeof(ntfs_inode *));
                free(base_ni->extent_nis);
            }
            base_ni->extent_nis = extent_nis;
        }
        base_ni->extent_nis[base_ni->nr_extents++] = ni;
    }
    /* Make sure the allocated inode is written out to disk later. */
    ntfs_inode_mark_dirty(ni);
    /* Initialize time, allocated and data size in ntfs_inode struct. */
    ni->data_size = ni->allocated_size = 0;
    ni->flags = 0;
    ni->creation_time = ni->last_data_change_time =
    ni->last_mft_change_time =
    ni->last_access_time = ntfs_current_time();
    /* Update the default mft allocation position if it was used. */
    if (!base_ni)
    vol->mft_data_pos = bit + 1;
    /* Return the opened, allocated inode of the allocated mft record. */
    ntfs_log_debug("allocated %sinode 0x%llx.\n",
            base_ni ? "extent " : "", (long long)bit);
    vol->free_mft_records--;
    out:
    ntfs_log_leave("\n");
    return ni;

    undo_mftbmp_alloc:
    err = errno;
    if (ntfs_bitmap_clear_bit(mftbmp_na, bit))
    ntfs_log_error("Failed to clear bit in mft bitmap.%s\n", es);
    errno = err;
    err_out:
    if (!errno)
    errno = EIO;
    ni = NULL;
    goto out;
}

/**
 * ntfs_mft_record_free - free an mft record on an ntfs volume
 * @vol:	volume on which to free the mft record
 * @ni:		open ntfs inode of the mft record to free
 *
 * Free the mft record of the open inode @ni on the mounted ntfs volume @vol.
 * Note that this function calls ntfs_inode_close() internally and hence you
 * cannot use the pointer @ni any more after this function returns success.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
int ntfs_mft_record_free(ntfs_volume *vol, ntfs_inode *ni)
{
    u64 mft_no;
    int err;
    u16 seq_no;
    le16 old_seq_no;

    ntfs_log_trace("Entering for inode 0x%llx.\n", (long long) ni->mft_no);

    if (!vol || !vol->mftbmp_na || !ni)
    {
        errno = EINVAL;
        return -1;
    }

    /* Cache the mft reference for later. */
    mft_no = ni->mft_no;

    /* Mark the mft record as not in use. */
    ni->mrec->flags &= ~MFT_RECORD_IN_USE;

    /* Increment the sequence number, skipping zero, if it is not zero. */
    old_seq_no = ni->mrec->sequence_number;
    seq_no = le16_to_cpu(old_seq_no);
    if (seq_no == 0xffff)
        seq_no = 1;
    else if (seq_no) seq_no++;
    ni->mrec->sequence_number = cpu_to_le16(seq_no);

    /* Set the inode dirty and write it out. */
    ntfs_inode_mark_dirty(ni);
    if (ntfs_inode_sync(ni))
    {
        err = errno;
        goto sync_rollback;
    }

    /* Clear the bit in the $MFT/$BITMAP corresponding to this record. */
    if (ntfs_bitmap_clear_bit(vol->mftbmp_na, mft_no))
    {
        err = errno;
        // FIXME: If ntfs_bitmap_clear_run() guarantees rollback on
        //	  error, this could be changed to goto sync_rollback;
        goto bitmap_rollback;
    }

    /* Throw away the now freed inode. */
#if CACHE_NIDATA_SIZE
    if (!ntfs_inode_real_close(ni))
    {
#else
        if (!ntfs_inode_close(ni))
        {
#endif
        vol->free_mft_records++;
        return 0;
    }
    err = errno;

    /* Rollback what we did... */
    bitmap_rollback: if (ntfs_bitmap_set_bit(vol->mftbmp_na, mft_no))
    ntfs_log_debug("Eeek! Rollback failed in ntfs_mft_record_free().  "
            "Leaving inconsistent metadata!\n");
    sync_rollback: ni->mrec->flags |= MFT_RECORD_IN_USE;
    ni->mrec->sequence_number = old_seq_no;
    ntfs_inode_mark_dirty(ni);
    errno = err;
    return -1;
}

/**
 * ntfs_mft_usn_dec - Decrement USN by one
 * @mrec:	pointer to an mft record
 *
 * On success return 0 and on error return -1 with errno set.
 */
int ntfs_mft_usn_dec(MFT_RECORD *mrec)
{
    u16 usn;
    le16 *usnp;

    if (!mrec)
    {
        errno = EINVAL;
        return -1;
    }
    usnp = (le16*) ((char*) mrec + le16_to_cpu(mrec->usa_ofs));
    usn = le16_to_cpup(usnp);
    if (usn-- <= 1) usn = 0xfffe;
    *usnp = cpu_to_le16(usn);

    return 0;
}