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libntfs/source/lcnalloc.c

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/**
* lcnalloc.c - Cluster (de)allocation code. Originated from the Linux-NTFS project.
*
* Copyright (c) 2002-2004 Anton Altaparmakov
* Copyright (c) 2004 Yura Pakhuchiy
* Copyright (c) 2004-2008 Szabolcs Szakacsits
* Copyright (c) 2008-2009 Jean-Pierre Andre
*
* 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
#include "types.h"
#include "attrib.h"
#include "bitmap.h"
#include "debug.h"
#include "runlist.h"
#include "volume.h"
#include "lcnalloc.h"
#include "logging.h"
#include "misc.h"
/*
* Plenty possibilities for big optimizations all over in the cluster
* allocation, however at the moment the dominant bottleneck (~ 90%) is
* the update of the mapping pairs which converges to the cubic Faulhaber's
* formula as the function of the number of extents (fragments, runs).
*/
#define NTFS_LCNALLOC_BSIZE 4096
#define NTFS_LCNALLOC_SKIP NTFS_LCNALLOC_BSIZE
enum {
ZONE_MFT = 1,
ZONE_DATA1 = 2,
ZONE_DATA2 = 4
} ;
static void ntfs_cluster_set_zone_pos(LCN start, LCN end, LCN *pos, LCN tc)
{
ntfs_log_trace("pos: %lld tc: %lld\n", (long long)*pos, (long long)tc);
if (tc >= end)
*pos = start;
else if (tc >= start)
*pos = tc;
}
static void ntfs_cluster_update_zone_pos(ntfs_volume *vol, u8 zone, LCN tc)
{
ntfs_log_trace("tc = %lld, zone = %d\n", (long long)tc, zone);
if (zone == ZONE_MFT)
ntfs_cluster_set_zone_pos(vol->mft_lcn, vol->mft_zone_end,
&vol->mft_zone_pos, tc);
else if (zone == ZONE_DATA1)
ntfs_cluster_set_zone_pos(vol->mft_zone_end, vol->nr_clusters,
&vol->data1_zone_pos, tc);
else /* zone == ZONE_DATA2 */
ntfs_cluster_set_zone_pos(0, vol->mft_zone_start,
&vol->data2_zone_pos, tc);
}
/*
* Unmark full zones when a cluster has been freed in a full zone
*
* Next allocation will reuse the freed cluster
*/
static void update_full_status(ntfs_volume *vol, LCN lcn)
{
if (lcn >= vol->mft_zone_end) {
if (vol->full_zones & ZONE_DATA1) {
ntfs_cluster_update_zone_pos(vol, ZONE_DATA1, lcn);
vol->full_zones &= ~ZONE_DATA1;
}
} else
if (lcn < vol->mft_zone_start) {
if (vol->full_zones & ZONE_DATA2) {
ntfs_cluster_update_zone_pos(vol, ZONE_DATA2, lcn);
vol->full_zones &= ~ZONE_DATA2;
}
} else {
if (vol->full_zones & ZONE_MFT) {
ntfs_cluster_update_zone_pos(vol, ZONE_MFT, lcn);
vol->full_zones &= ~ZONE_MFT;
}
}
}
static s64 max_empty_bit_range(unsigned char *buf, int size)
{
int i, j, run = 0;
int max_range = 0;
s64 start_pos = -1;
ntfs_log_trace("Entering\n");
i = 0;
while (i < size) {
switch (*buf) {
case 0 :
do {
buf++;
run += 8;
i++;
} while ((i < size) && !*buf);
break;
case 255 :
if (run > max_range) {
max_range = run;
start_pos = (s64)i * 8 - run;
}
run = 0;
do {
buf++;
i++;
} while ((i < size) && (*buf == 255));
break;
default :
for (j = 0; j < 8; j++) {
int bit = *buf & (1 << j);
if (bit) {
if (run > max_range) {
max_range = run;
start_pos = (s64)i * 8 + (j - run);
}
run = 0;
} else
run++;
}
i++;
buf++;
}
}
if (run > max_range)
start_pos = (s64)i * 8 - run;
return start_pos;
}
static int bitmap_writeback(ntfs_volume *vol, s64 pos, s64 size, void *b,
u8 *writeback)
{
s64 written;
ntfs_log_trace("Entering\n");
if (!*writeback)
return 0;
*writeback = 0;
written = ntfs_attr_pwrite(vol->lcnbmp_na, pos, size, b);
if (written != size) {
if (!written)
errno = EIO;
ntfs_log_perror("Bitmap write error (%lld, %lld)",
(long long)pos, (long long)size);
return -1;
}
return 0;
}
/**
* ntfs_cluster_alloc - allocate clusters on an ntfs volume
* @vol: mounted ntfs volume on which to allocate the clusters
* @start_vcn: vcn to use for the first allocated cluster
* @count: number of clusters to allocate
* @start_lcn: starting lcn at which to allocate the clusters (or -1 if none)
* @zone: zone from which to allocate the clusters
*
* Allocate @count clusters preferably starting at cluster @start_lcn or at the
* current allocator position if @start_lcn is -1, on the mounted ntfs volume
* @vol. @zone is either DATA_ZONE for allocation of normal clusters and
* MFT_ZONE for allocation of clusters for the master file table, i.e. the
* $MFT/$DATA attribute.
*
* On success return a runlist describing the allocated cluster(s).
*
* On error return NULL with errno set to the error code.
*
* Notes on the allocation algorithm
* =================================
*
* There are two data zones. First is the area between the end of the mft zone
* and the end of the volume, and second is the area between the start of the
* volume and the start of the mft zone. On unmodified/standard NTFS 1.x
* volumes, the second data zone doesn't exist due to the mft zone being
* expanded to cover the start of the volume in order to reserve space for the
* mft bitmap attribute.
*
* The complexity stems from the need of implementing the mft vs data zoned
* approach and from the fact that we have access to the lcn bitmap via up to
* NTFS_LCNALLOC_BSIZE bytes at a time, so we need to cope with crossing over
* boundaries of two buffers. Further, the fact that the allocator allows for
* caller supplied hints as to the location of where allocation should begin
* and the fact that the allocator keeps track of where in the data zones the
* next natural allocation should occur, contribute to the complexity of the
* function. But it should all be worthwhile, because this allocator:
* 1) implements MFT zone reservation
* 2) causes reduction in fragmentation.
* The code is not optimized for speed.
*/
runlist *ntfs_cluster_alloc(ntfs_volume *vol, VCN start_vcn, s64 count,
LCN start_lcn, const NTFS_CLUSTER_ALLOCATION_ZONES zone)
{
LCN zone_start, zone_end; /* current search range */
LCN last_read_pos, lcn;
LCN bmp_pos; /* current bit position inside the bitmap */
LCN prev_lcn = 0, prev_run_len = 0;
s64 clusters, br;
runlist *rl = NULL, *trl;
u8 *buf, *byte, bit, writeback;
u8 pass = 1; /* 1: inside zone; 2: start of zone */
u8 search_zone; /* 4: data2 (start) 1: mft (middle) 2: data1 (end) */
u8 done_zones = 0;
u8 has_guess, used_zone_pos;
int err = 0, rlpos, rlsize, buf_size;
ntfs_log_enter("Entering with count = 0x%llx, start_lcn = 0x%llx, "
"zone = %s_ZONE.\n", (long long)count, (long long)
start_lcn, zone == MFT_ZONE ? "MFT" : "DATA");
if (!vol || count < 0 || start_lcn < -1 || !vol->lcnbmp_na ||
(s8)zone < FIRST_ZONE || zone > LAST_ZONE) {
errno = EINVAL;
ntfs_log_perror("%s: vcn: %lld, count: %lld, lcn: %lld",
__FUNCTION__, (long long)start_vcn,
(long long)count, (long long)start_lcn);
goto out;
}
/* Return empty runlist if @count == 0 */
if (!count) {
rl = ntfs_malloc(0x1000);
if (rl) {
rl[0].vcn = start_vcn;
rl[0].lcn = LCN_RL_NOT_MAPPED;
rl[0].length = 0;
}
goto out;
}
buf = ntfs_malloc(NTFS_LCNALLOC_BSIZE);
if (!buf)
goto out;
/*
* If no @start_lcn was requested, use the current zone
* position otherwise use the requested @start_lcn.
*/
has_guess = 1;
zone_start = start_lcn;
if (zone_start < 0) {
if (zone == DATA_ZONE)
zone_start = vol->data1_zone_pos;
else
zone_start = vol->mft_zone_pos;
has_guess = 0;
}
used_zone_pos = has_guess ? 0 : 1;
if (!zone_start || zone_start == vol->mft_zone_start ||
zone_start == vol->mft_zone_end)
pass = 2;
if (zone_start < vol->mft_zone_start) {
zone_end = vol->mft_zone_start;
search_zone = ZONE_DATA2;
} else if (zone_start < vol->mft_zone_end) {
zone_end = vol->mft_zone_end;
search_zone = ZONE_MFT;
} else {
zone_end = vol->nr_clusters;
search_zone = ZONE_DATA1;
}
bmp_pos = zone_start;
/* Loop until all clusters are allocated. */
clusters = count;
rlpos = rlsize = 0;
while (1) {
/* check whether we have exhausted the current zone */
if (search_zone & vol->full_zones)
goto zone_pass_done;
last_read_pos = bmp_pos >> 3;
br = ntfs_attr_pread(vol->lcnbmp_na, last_read_pos,
NTFS_LCNALLOC_BSIZE, buf);
if (br <= 0) {
if (!br)
goto zone_pass_done;
err = errno;
ntfs_log_perror("Reading $BITMAP failed");
goto err_ret;
}
/*
* We might have read less than NTFS_LCNALLOC_BSIZE bytes
* if we are close to the end of the attribute.
*/
buf_size = (int)br << 3;
lcn = bmp_pos & 7;
bmp_pos &= ~7;
writeback = 0;
while (lcn < buf_size) {
byte = buf + (lcn >> 3);
bit = 1 << (lcn & 7);
if (has_guess) {
if (*byte & bit) {
has_guess = 0;
break;
}
} else {
lcn = max_empty_bit_range(buf, br);
if (lcn < 0)
break;
has_guess = 1;
continue;
}
/* First free bit is at lcn + bmp_pos. */
/* Reallocate memory if necessary. */
if ((rlpos + 2) * (int)sizeof(runlist) >= rlsize) {
rlsize += 4096;
trl = realloc(rl, rlsize);
if (!trl) {
err = ENOMEM;
ntfs_log_perror("realloc() failed");
goto wb_err_ret;
}
rl = trl;
}
/* Allocate the bitmap bit. */
*byte |= bit;
writeback = 1;
if (vol->free_clusters <= 0)
ntfs_log_error("Non-positive free clusters "
"(%lld)!\n",
(long long)vol->free_clusters);
else
vol->free_clusters--;
/*
* Coalesce with previous run if adjacent LCNs.
* Otherwise, append a new run.
*/
if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
ntfs_log_debug("Cluster coalesce: prev_lcn: "
"%lld lcn: %lld bmp_pos: %lld "
"prev_run_len: %lld\n",
(long long)prev_lcn,
(long long)lcn, (long long)bmp_pos,
(long long)prev_run_len);
rl[rlpos - 1].length = ++prev_run_len;
} else {
if (rlpos)
rl[rlpos].vcn = rl[rlpos - 1].vcn +
prev_run_len;
else {
rl[rlpos].vcn = start_vcn;
ntfs_log_debug("Start_vcn: %lld\n",
(long long)start_vcn);
}
rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
rl[rlpos].length = prev_run_len = 1;
rlpos++;
}
ntfs_log_debug("RUN: %-16lld %-16lld %-16lld\n",
(long long)rl[rlpos - 1].vcn,
(long long)rl[rlpos - 1].lcn,
(long long)rl[rlpos - 1].length);
/* Done? */
if (!--clusters) {
if (used_zone_pos)
ntfs_cluster_update_zone_pos(vol,
search_zone, lcn + bmp_pos + 1 +
NTFS_LCNALLOC_SKIP);
goto done_ret;
}
lcn++;
}
if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback)) {
err = errno;
goto err_ret;
}
if (!used_zone_pos) {
used_zone_pos = 1;
if (search_zone == ZONE_MFT)
zone_start = vol->mft_zone_pos;
else if (search_zone == ZONE_DATA1)
zone_start = vol->data1_zone_pos;
else
zone_start = vol->data2_zone_pos;
if (!zone_start || zone_start == vol->mft_zone_start ||
zone_start == vol->mft_zone_end)
pass = 2;
bmp_pos = zone_start;
} else
bmp_pos += buf_size;
if (bmp_pos < zone_end)
continue;
zone_pass_done:
ntfs_log_trace("Finished current zone pass(%i).\n", pass);
if (pass == 1) {
pass = 2;
zone_end = zone_start;
if (search_zone == ZONE_MFT)
zone_start = vol->mft_zone_start;
else if (search_zone == ZONE_DATA1)
zone_start = vol->mft_zone_end;
else
zone_start = 0;
/* Sanity check. */
if (zone_end < zone_start)
zone_end = zone_start;
bmp_pos = zone_start;
continue;
}
/* pass == 2 */
done_zones_check:
done_zones |= search_zone;
vol->full_zones |= search_zone;
if (done_zones < (ZONE_MFT + ZONE_DATA1 + ZONE_DATA2)) {
ntfs_log_trace("Switching zone.\n");
pass = 1;
if (rlpos) {
LCN tc = rl[rlpos - 1].lcn +
rl[rlpos - 1].length + NTFS_LCNALLOC_SKIP;
if (used_zone_pos)
ntfs_cluster_update_zone_pos(vol,
search_zone, tc);
}
switch (search_zone) {
case ZONE_MFT:
ntfs_log_trace("Zone switch: mft -> data1\n");
switch_to_data1_zone: search_zone = ZONE_DATA1;
zone_start = vol->data1_zone_pos;
zone_end = vol->nr_clusters;
if (zone_start == vol->mft_zone_end)
pass = 2;
break;
case ZONE_DATA1:
ntfs_log_trace("Zone switch: data1 -> data2\n");
search_zone = ZONE_DATA2;
zone_start = vol->data2_zone_pos;
zone_end = vol->mft_zone_start;
if (!zone_start)
pass = 2;
break;
case ZONE_DATA2:
if (!(done_zones & ZONE_DATA1)) {
ntfs_log_trace("data2 -> data1\n");
goto switch_to_data1_zone;
}
ntfs_log_trace("Zone switch: data2 -> mft\n");
search_zone = ZONE_MFT;
zone_start = vol->mft_zone_pos;
zone_end = vol->mft_zone_end;
if (zone_start == vol->mft_zone_start)
pass = 2;
break;
}
bmp_pos = zone_start;
if (zone_start == zone_end) {
ntfs_log_trace("Empty zone, skipped.\n");
goto done_zones_check;
}
continue;
}
ntfs_log_trace("All zones are finished, no space on device.\n");
err = ENOSPC;
goto err_ret;
}
done_ret:
ntfs_log_debug("At done_ret.\n");
/* Add runlist terminator element. */
rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
rl[rlpos].length = 0;
if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback)) {
err = errno;
goto err_ret;
}
done_err_ret:
free(buf);
if (err) {
errno = err;
ntfs_log_perror("Failed to allocate clusters");
rl = NULL;
}
out:
ntfs_log_leave("\n");
return rl;
wb_err_ret:
ntfs_log_trace("At wb_err_ret.\n");
if (bitmap_writeback(vol, last_read_pos, br, buf, &writeback))
err = errno;
err_ret:
ntfs_log_trace("At err_ret.\n");
if (rl) {
/* Add runlist terminator element. */
rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
rl[rlpos].length = 0;
ntfs_debug_runlist_dump(rl);
ntfs_cluster_free_from_rl(vol, rl);
free(rl);
rl = NULL;
}
goto done_err_ret;
}
/**
* ntfs_cluster_free_from_rl - free clusters from runlist
* @vol: mounted ntfs volume on which to free the clusters
* @rl: runlist from which deallocate clusters
*
* On success return 0 and on error return -1 with errno set to the error code.
*/
int ntfs_cluster_free_from_rl(ntfs_volume *vol, runlist *rl)
{
s64 nr_freed = 0;
int ret = -1;
ntfs_log_trace("Entering.\n");
for (; rl->length; rl++) {
ntfs_log_trace("Dealloc lcn 0x%llx, len 0x%llx.\n",
(long long)rl->lcn, (long long)rl->length);
if (rl->lcn >= 0) {
update_full_status(vol,rl->lcn);
if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn,
rl->length)) {
ntfs_log_perror("Cluster deallocation failed "
"(%lld, %lld)",
(long long)rl->lcn,
(long long)rl->length);
goto out;
}
nr_freed += rl->length ;
}
}
ret = 0;
out:
vol->free_clusters += nr_freed;
if (vol->free_clusters > vol->nr_clusters)
ntfs_log_error("Too many free clusters (%lld > %lld)!",
(long long)vol->free_clusters,
(long long)vol->nr_clusters);
return ret;
}
/*
* Basic cluster run free
* Returns 0 if successful
*/
int ntfs_cluster_free_basic(ntfs_volume *vol, s64 lcn, s64 count)
{
s64 nr_freed = 0;
int ret = -1;
ntfs_log_trace("Entering.\n");
ntfs_log_trace("Dealloc lcn 0x%llx, len 0x%llx.\n",
(long long)lcn, (long long)count);
if (lcn >= 0) {
update_full_status(vol,lcn);
if (ntfs_bitmap_clear_run(vol->lcnbmp_na, lcn,
count)) {
ntfs_log_perror("Cluster deallocation failed "
"(%lld, %lld)",
(long long)lcn,
(long long)count);
goto out;
}
nr_freed += count;
}
ret = 0;
out:
vol->free_clusters += nr_freed;
if (vol->free_clusters > vol->nr_clusters)
ntfs_log_error("Too many free clusters (%lld > %lld)!",
(long long)vol->free_clusters,
(long long)vol->nr_clusters);
return ret;
}
/**
* ntfs_cluster_free - free clusters on an ntfs volume
* @vol: mounted ntfs volume on which to free the clusters
* @na: attribute whose runlist describes the clusters to free
* @start_vcn: vcn in @rl at which to start freeing clusters
* @count: number of clusters to free or -1 for all clusters
*
* Free @count clusters starting at the cluster @start_vcn in the runlist
* described by the attribute @na from the mounted ntfs volume @vol.
*
* If @count is -1, all clusters from @start_vcn to the end of the runlist
* are deallocated.
*
* On success return the number of deallocated clusters (not counting sparse
* clusters) and on error return -1 with errno set to the error code.
*/
int ntfs_cluster_free(ntfs_volume *vol, ntfs_attr *na, VCN start_vcn, s64 count)
{
runlist *rl;
s64 delta, to_free, nr_freed = 0;
int ret = -1;
if (!vol || !vol->lcnbmp_na || !na || start_vcn < 0 ||
(count < 0 && count != -1)) {
ntfs_log_trace("Invalid arguments!\n");
errno = EINVAL;
return -1;
}
ntfs_log_enter("Entering for inode 0x%llx, attr 0x%x, count 0x%llx, "
"vcn 0x%llx.\n", (unsigned long long)na->ni->mft_no,
na->type, (long long)count, (long long)start_vcn);
rl = ntfs_attr_find_vcn(na, start_vcn);
if (!rl) {
if (errno == ENOENT)
ret = 0;
goto leave;
}
if (rl->lcn < 0 && rl->lcn != LCN_HOLE) {
errno = EIO;
ntfs_log_perror("%s: Unexpected lcn (%lld)", __FUNCTION__,
(long long)rl->lcn);
goto leave;
}
/* Find the starting cluster inside the run that needs freeing. */
delta = start_vcn - rl->vcn;
/* The number of clusters in this run that need freeing. */
to_free = rl->length - delta;
if (count >= 0 && to_free > count)
to_free = count;
if (rl->lcn != LCN_HOLE) {
/* Do the actual freeing of the clusters in this run. */
update_full_status(vol,rl->lcn + delta);
if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn + delta,
to_free))
goto leave;
nr_freed = to_free;
}
/* Go to the next run and adjust the number of clusters left to free. */
++rl;
if (count >= 0)
count -= to_free;
/*
* Loop over the remaining runs, using @count as a capping value, and
* free them.
*/
for (; rl->length && count != 0; ++rl) {
// FIXME: Need to try ntfs_attr_map_runlist() for attribute
// list support! (AIA)
if (rl->lcn < 0 && rl->lcn != LCN_HOLE) {
// FIXME: Eeek! We need rollback! (AIA)
errno = EIO;
ntfs_log_perror("%s: Invalid lcn (%lli)",
__FUNCTION__, (long long)rl->lcn);
goto out;
}
/* The number of clusters in this run that need freeing. */
to_free = rl->length;
if (count >= 0 && to_free > count)
to_free = count;
if (rl->lcn != LCN_HOLE) {
update_full_status(vol,rl->lcn);
if (ntfs_bitmap_clear_run(vol->lcnbmp_na, rl->lcn,
to_free)) {
// FIXME: Eeek! We need rollback! (AIA)
ntfs_log_perror("%s: Clearing bitmap run failed",
__FUNCTION__);
goto out;
}
nr_freed += to_free;
}
if (count >= 0)
count -= to_free;
}
if (count != -1 && count != 0) {
// FIXME: Eeek! BUG()
errno = EIO;
ntfs_log_perror("%s: count still not zero (%lld)", __FUNCTION__,
(long long)count);
goto out;
}
ret = nr_freed;
out:
vol->free_clusters += nr_freed ;
if (vol->free_clusters > vol->nr_clusters)
ntfs_log_error("Too many free clusters (%lld > %lld)!",
(long long)vol->free_clusters,
(long long)vol->nr_clusters);
leave:
ntfs_log_leave("\n");
return ret;
}
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