- 根目录:
- fs
- ntfs
- lcnalloc.c
/*
* lcnalloc.c - Cluster (de)allocation code. Part of the Linux-NTFS project.
*
* Copyright (c) 2004-2005 Anton Altaparmakov
*
* This program/include file is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program/include file is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (in the main directory of the Linux-NTFS
* distribution in the file COPYING); if not, write to the Free Software
* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifdef NTFS_RW
#include <linux/pagemap.h>
#include "lcnalloc.h"
#include "debug.h"
#include "bitmap.h"
#include "inode.h"
#include "volume.h"
#include "attrib.h"
#include "malloc.h"
#include "aops.h"
#include "ntfs.h"
/**
* ntfs_cluster_free_from_rl_nolock - free clusters from runlist
* @vol: mounted ntfs volume on which to free the clusters
* @rl: runlist describing the clusters to free
*
* Free all the clusters described by the runlist @rl on the volume @vol. In
* the case of an error being returned, at least some of the clusters were not
* freed.
*
* Return 0 on success and -errno on error.
*
* Locking: - The volume lcn bitmap must be locked for writing on entry and is
* left locked on return.
*/
int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
const runlist_element *rl)
{
struct inode *lcnbmp_vi = vol->lcnbmp_ino;
int ret = 0;
ntfs_debug("Entering.");
if (!rl)
return 0;
for (; rl->length; rl++) {
int err;
if (rl->lcn < 0)
continue;
err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length);
if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err))
ret = err;
}
ntfs_debug("Done.");
return ret;
}
/**
* 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
* @is_extension: if 'true', this is an attribute extension
*
* 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 or
* MFT_ZONE for allocation of clusters for the master file table, i.e. the
* $MFT/$DATA attribute.
*
* @start_vcn specifies the vcn of the first allocated cluster. This makes
* merging the resulting runlist with the old runlist easier.
*
* If @is_extension is 'true', the caller is allocating clusters to extend an
* attribute and if it is 'false', the caller is allocating clusters to fill a
* hole in an attribute. Practically the difference is that if @is_extension
* is 'true' the returned runlist will be terminated with LCN_ENOENT and if
* @is_extension is 'false' the runlist will be terminated with
* LCN_RL_NOT_MAPPED.
*
* You need to check the return value with IS_ERR(). If this is false, the
* function was successful and the return value is a runlist describing the
* allocated cluster(s). If IS_ERR() is true, the function failed and
* PTR_ERR() gives you 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 does not 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.
*
* This is not the prettiest function but 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 in portions of up to 8192 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 should: 1) be a full implementation of
* the MFT zone approach used by Windows NT, 2) cause reduction in
* fragmentation, and 3) be speedy in allocations (the code is not optimized
* for speed, but the algorithm is, so further speed improvements are probably
* possible).
*
* FIXME: We should be monitoring cluster allocation and increment the MFT zone
* size dynamically but this is something for the future. We will just cause
* heavier fragmentation by not doing it and I am not even sure Windows would
* grow the MFT zone dynamically, so it might even be correct not to do this.
* The overhead in doing dynamic MFT zone expansion would be very large and
* unlikely worth the effort. (AIA)
*
* TODO: I have added in double the required zone position pointer wrap around
* logic which can be optimized to having only one of the two logic sets.
* However, having the double logic will work fine, but if we have only one of
* the sets and we get it wrong somewhere, then we get into trouble, so
* removing the duplicate logic requires _very_ careful consideration of _all_
* possible code paths. So at least for now, I am leaving the double logic -
* better safe than sorry... (AIA)
*
* Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked
* on return.
* - This function takes the volume lcn bitmap lock for writing and
* modifies the bitmap contents.
*/
runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
const s64 count, const LCN start_lcn,
const NTFS_CLUSTER_ALLOCATION_ZONES zone,
const bool is_extension)
{
LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
s64 clusters;
loff_t i_size;
struct inode *lcnbmp_vi;
runlist_element *rl = NULL;
struct address_space *mapping;
struct page *page = NULL;
u8 *buf, *byte;
int err = 0, rlpos, rlsize, buf_size;
u8 pass, done_zones, search_zone, need_writeback = 0, bit;
ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn "
"0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn,
(unsigned long long)count,
(unsigned long long)start_lcn,
zone == MFT_ZONE ? "MFT" : "DATA");
BUG_ON(!vol);
lcnbmp_vi = vol->lcnbmp_ino;
BUG_ON(!lcnbmp_vi);
BUG_ON(start_vcn < 0);
BUG_ON(count < 0);
BUG_ON(start_lcn < -1);
BUG_ON(zone < FIRST_ZONE);
BUG_ON(zone > LAST_ZONE);
/* Return NULL if @count is zero. */
if (!count)
return NULL;
/* Take the lcnbmp lock for writing. */
down_write(&vol->lcnbmp_lock);
/*
* If no specific @start_lcn was requested, use the current data zone
* position, otherwise use the requested @start_lcn but make sure it
* lies outside the mft zone. Also set done_zones to 0 (no zones done)
* and pass depending on whether we are starting inside a zone (1) or
* at the beginning of a zone (2). If requesting from the MFT_ZONE,
* we either start at the current position within the mft zone or at
* the specified position. If the latter is out of bounds then we start
* at the beginning of the MFT_ZONE.
*/
done_zones = 0;
pass = 1;
/*
* zone_start and zone_end are the current search range. search_zone
* is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of
* volume) and 4 for data zone 2 (start of volume till start of mft
* zone).
*/
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;
if (!zone_start) {
/*
* Zone starts at beginning of volume which means a
* single pass is sufficient.
*/
pass = 2;
}
} else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start &&
zone_start < vol->mft_zone_end) {
zone_start = vol->mft_zone_end;
/*
* Starting at beginning of data1_zone which means a single
* pass in this zone is sufficient.
*/
pass = 2;
} else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start ||
zone_start >= vol->mft_zone_end)) {
zone_start = vol->mft_lcn;
if (!vol->mft_zone_end)
zone_start = 0;
/*
* Starting at beginning of volume which means a single pass
* is sufficient.
*/
pass = 2;
}
if (zone == MFT_ZONE) {
zone_end = vol->mft_zone_end;
search_zone = 1;
} else /* if (zone == DATA_ZONE) */ {
/* Skip searching the mft zone. */
done_zones |= 1;
if (zone_start >= vol->mft_zone_end) {
zone_end = vol->nr_clusters;
search_zone = 2;
} else {
zone_end = vol->mft_zone_start;
search_zone = 4;
}
}
/*
* bmp_pos is the current bit position inside the bitmap. We use
* bmp_initial_pos to determine whether or not to do a zone switch.
*/
bmp_pos = bmp_initial_pos = zone_start;
/* Loop until all clusters are allocated, i.e. clusters == 0. */
clusters = count;
rlpos = rlsize = 0;
mapping = lcnbmp_vi->i_mapping;
i_size = i_size_read(lcnbmp_vi);
while (1) {
ntfs_debug("Start of outer while loop: done_zones 0x%x, "
"search_zone %i, pass %i, zone_start 0x%llx, "
"zone_end 0x%llx, bmp_initial_pos 0x%llx, "
"bmp_pos 0x%llx, rlpos %i, rlsize %i.",
done_zones, search_zone, pass,
(unsigned long long)zone_start,
(unsigned long long)zone_end,
(unsigned long long)bmp_initial_pos,
(unsigned long long)bmp_pos, rlpos, rlsize);
/* Loop until we run out of free clusters. */
last_read_pos = bmp_pos >> 3;
ntfs_debug("last_read_pos 0x%llx.",
(unsigned long long)last_read_pos);
if (last_read_pos > i_size) {
ntfs_debug("End of attribute reached. "
"Skipping to zone_pass_done.");
goto zone_pass_done;
}
if (likely(page)) {
if (need_writeback) {
ntfs_debug("Marking page dirty.");
flush_dcache_page(page);
set_page_dirty(page);
need_writeback = 0;
}
ntfs_unmap_page(page);
}
page = ntfs_map_page(mapping, last_read_pos >>
PAGE_CACHE_SHIFT);
if (IS_ERR(page)) {
err = PTR_ERR(page);
ntfs_error(vol->sb, "Failed to map page.");
goto out;
}
buf_size = last_read_pos & ~PAGE_CACHE_MASK;
buf = page_address(page) + buf_size;
buf_size = PAGE_CACHE_SIZE - buf_size;
if (unlikely(last_read_pos + buf_size > i_size))
buf_size = i_size - last_read_pos;
buf_size <<= 3;
lcn = bmp_pos & 7;
bmp_pos &= ~(LCN)7;
ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, "
"bmp_pos 0x%llx, need_writeback %i.", buf_size,
(unsigned long long)lcn,
(unsigned long long)bmp_pos, need_writeback);
while (lcn < buf_size && lcn + bmp_pos < zone_end) {
byte = buf + (lcn >> 3);
ntfs_debug("In inner while loop: buf_size %i, "
"lcn 0x%llx, bmp_pos 0x%llx, "
"need_writeback %i, byte ofs 0x%x, "
"*byte 0x%x.", buf_size,
(unsigned long long)lcn,
(unsigned long long)bmp_pos,
need_writeback,
(unsigned int)(lcn >> 3),
(unsigned int)*byte);
/* Skip full bytes. */
if (*byte == 0xff) {
lcn = (lcn + 8) & ~(LCN)7;
ntfs_debug("Continuing while loop 1.");
continue;
}
bit = 1 << (lcn & 7);
ntfs_debug("bit 0x%x.", bit);
/* If the bit is already set, go onto the next one. */
if (*byte & bit) {
lcn++;
ntfs_debug("Continuing while loop 2.");
continue;
}
/*
* Allocate more memory if needed, including space for
* the terminator element.
* ntfs_malloc_nofs() operates on whole pages only.
*/
if ((rlpos + 2) * sizeof(*rl) > rlsize) {
runlist_element *rl2;
ntfs_debug("Reallocating memory.");
if (!rl)
ntfs_debug("First free bit is at LCN "
"0x%llx.",
(unsigned long long)
(lcn + bmp_pos));
rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
if (unlikely(!rl2)) {
err = -ENOMEM;
ntfs_error(vol->sb, "Failed to "
"allocate memory.");
goto out;
}
memcpy(rl2, rl, rlsize);
ntfs_free(rl);
rl = rl2;
rlsize += PAGE_SIZE;
ntfs_debug("Reallocated memory, rlsize 0x%x.",
rlsize);
}
/* Allocate the bitmap bit. */
*byte |= bit;
/* We need to write this bitmap page to disk. */
need_writeback = 1;
ntfs_debug("*byte 0x%x, need_writeback is set.",
(unsigned int)*byte);
/*
* Coalesce with previous run if adjacent LCNs.
* Otherwise, append a new run.
*/
ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), "
"prev_lcn 0x%llx, lcn 0x%llx, "
"bmp_pos 0x%llx, prev_run_len 0x%llx, "
"rlpos %i.",
(unsigned long long)(lcn + bmp_pos),
1ULL, (unsigned long long)prev_lcn,
(unsigned long long)lcn,
(unsigned long long)bmp_pos,
(unsigned long long)prev_run_len,
rlpos);
if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
ntfs_debug("Coalescing to run (lcn 0x%llx, "
"len 0x%llx).",
(unsigned long long)
rl[rlpos - 1].lcn,
(unsigned long long)
rl[rlpos - 1].length);
rl[rlpos - 1].length = ++prev_run_len;
ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), "
"prev_run_len 0x%llx.",
(unsigned long long)
rl[rlpos - 1].lcn,
(unsigned long long)
rl[rlpos - 1].length,
(unsigned long long)
prev_run_len);
} else {
if (likely(rlpos)) {
ntfs_debug("Adding new run, (previous "
"run lcn 0x%llx, "
"len 0x%llx).",
(unsigned long long)
rl[rlpos - 1].lcn,
(unsigned long long)
rl[rlpos - 1].length);
rl[rlpos].vcn = rl[rlpos - 1].vcn +
prev_run_len;
} else {
ntfs_debug("Adding new run, is first "
"run.");
rl[rlpos].vcn = start_vcn;
}
rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
rl[rlpos].length = prev_run_len = 1;
rlpos++;
}
/* Done? */
if (!--clusters) {
LCN tc;
/*
* Update the current zone position. Positions
* of already scanned zones have been updated
* during the respective zone switches.
*/
tc = lcn + bmp_pos + 1;
ntfs_debug("Done. Updating current zone "
"position, tc 0x%llx, "
"search_zone %i.",
(unsigned long long)tc,
search_zone);
switch (search_zone) {
case 1:
ntfs_debug("Before checks, "
"vol->mft_zone_pos "
"0x%llx.",
(unsigned long long)
vol->mft_zone_pos);
if (tc >= vol->mft_zone_end) {
vol->mft_zone_pos =
vol->mft_lcn;
if (!vol->mft_zone_end)
vol->mft_zone_pos = 0;
} else if ((bmp_initial_pos >=
vol->mft_zone_pos ||
tc > vol->mft_zone_pos)
&& tc >= vol->mft_lcn)
vol->mft_zone_pos = tc;
ntfs_debug("After checks, "
"vol->mft_zone_pos "
"0x%llx.",
(unsigned long long)
vol->mft_zone_pos);
break;
case 2:
ntfs_debug("Before checks, "
"vol->data1_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data1_zone_pos);
if (tc >= vol->nr_clusters)
vol->data1_zone_pos =
vol->mft_zone_end;
else if ((bmp_initial_pos >=
vol->data1_zone_pos ||
tc > vol->data1_zone_pos)
&& tc >= vol->mft_zone_end)
vol->data1_zone_pos = tc;
ntfs_debug("After checks, "
"vol->data1_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data1_zone_pos);
break;
case 4:
ntfs_debug("Before checks, "
"vol->data2_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data2_zone_pos);
if (tc >= vol->mft_zone_start)
vol->data2_zone_pos = 0;
else if (bmp_initial_pos >=
vol->data2_zone_pos ||
tc > vol->data2_zone_pos)
vol->data2_zone_pos = tc;
ntfs_debug("After checks, "
"vol->data2_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data2_zone_pos);
break;
default:
BUG();
}
ntfs_debug("Finished. Going to out.");
goto out;
}
lcn++;
}
bmp_pos += buf_size;
ntfs_debug("After inner while loop: buf_size 0x%x, lcn "
"0x%llx, bmp_pos 0x%llx, need_writeback %i.",
buf_size, (unsigned long long)lcn,
(unsigned long long)bmp_pos, need_writeback);
if (bmp_pos < zone_end) {
ntfs_debug("Continuing outer while loop, "
"bmp_pos 0x%llx, zone_end 0x%llx.",
(unsigned long long)bmp_pos,
(unsigned long long)zone_end);
continue;
}
zone_pass_done: /* Finished with the current zone pass. */
ntfs_debug("At zone_pass_done, pass %i.", pass);
if (pass == 1) {
/*
* Now do pass 2, scanning the first part of the zone
* we omitted in pass 1.
*/
pass = 2;
zone_end = zone_start;
switch (search_zone) {
case 1: /* mft_zone */
zone_start = vol->mft_zone_start;
break;
case 2: /* data1_zone */
zone_start = vol->mft_zone_end;
break;
case 4: /* data2_zone */
zone_start = 0;
break;
default:
BUG();
}
/* Sanity check. */
if (zone_end < zone_start)
zone_end = zone_start;
bmp_pos = zone_start;
ntfs_debug("Continuing outer while loop, pass 2, "
"zone_start 0x%llx, zone_end 0x%llx, "
"bmp_pos 0x%llx.",
(unsigned long long)zone_start,
(unsigned long long)zone_end,
(unsigned long long)bmp_pos);
continue;
} /* pass == 2 */
done_zones_check:
ntfs_debug("At done_zones_check, search_zone %i, done_zones "
"before 0x%x, done_zones after 0x%x.",
search_zone, done_zones,
done_zones | search_zone);
done_zones |= search_zone;
if (done_zones < 7) {
ntfs_debug("Switching zone.");
/* Now switch to the next zone we haven't done yet. */
pass = 1;
switch (search_zone) {
case 1:
ntfs_debug("Switching from mft zone to data1 "
"zone.");
/* Update mft zone position. */
if (rlpos) {
LCN tc;
ntfs_debug("Before checks, "
"vol->mft_zone_pos "
"0x%llx.",
(unsigned long long)
vol->mft_zone_pos);
tc = rl[rlpos - 1].lcn +
rl[rlpos - 1].length;
if (tc >= vol->mft_zone_end) {
vol->mft_zone_pos =
vol->mft_lcn;
if (!vol->mft_zone_end)
vol->mft_zone_pos = 0;
} else if ((bmp_initial_pos >=
vol->mft_zone_pos ||
tc > vol->mft_zone_pos)
&& tc >= vol->mft_lcn)
vol->mft_zone_pos = tc;
ntfs_debug("After checks, "
"vol->mft_zone_pos "
"0x%llx.",
(unsigned long long)
vol->mft_zone_pos);
}
/* Switch from mft zone to data1 zone. */
switch_to_data1_zone: search_zone = 2;
zone_start = bmp_initial_pos =
vol->data1_zone_pos;
zone_end = vol->nr_clusters;
if (zone_start == vol->mft_zone_end)
pass = 2;
if (zone_start >= zone_end) {
vol->data1_zone_pos = zone_start =
vol->mft_zone_end;
pass = 2;
}
break;
case 2:
ntfs_debug("Switching from data1 zone to "
"data2 zone.");
/* Update data1 zone position. */
if (rlpos) {
LCN tc;
ntfs_debug("Before checks, "
"vol->data1_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data1_zone_pos);
tc = rl[rlpos - 1].lcn +
rl[rlpos - 1].length;
if (tc >= vol->nr_clusters)
vol->data1_zone_pos =
vol->mft_zone_end;
else if ((bmp_initial_pos >=
vol->data1_zone_pos ||
tc > vol->data1_zone_pos)
&& tc >= vol->mft_zone_end)
vol->data1_zone_pos = tc;
ntfs_debug("After checks, "
"vol->data1_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data1_zone_pos);
}
/* Switch from data1 zone to data2 zone. */
search_zone = 4;
zone_start = bmp_initial_pos =
vol->data2_zone_pos;
zone_end = vol->mft_zone_start;
if (!zone_start)
pass = 2;
if (zone_start >= zone_end) {
vol->data2_zone_pos = zone_start =
bmp_initial_pos = 0;
pass = 2;
}
break;
case 4:
ntfs_debug("Switching from data2 zone to "
"data1 zone.");
/* Update data2 zone position. */
if (rlpos) {
LCN tc;
ntfs_debug("Before checks, "
"vol->data2_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data2_zone_pos);
tc = rl[rlpos - 1].lcn +
rl[rlpos - 1].length;
if (tc >= vol->mft_zone_start)
vol->data2_zone_pos = 0;
else if (bmp_initial_pos >=
vol->data2_zone_pos ||
tc > vol->data2_zone_pos)
vol->data2_zone_pos = tc;
ntfs_debug("After checks, "
"vol->data2_zone_pos "
"0x%llx.",
(unsigned long long)
vol->data2_zone_pos);
}
/* Switch from data2 zone to data1 zone. */
goto switch_to_data1_zone;
default:
BUG();
}
ntfs_debug("After zone switch, search_zone %i, "
"pass %i, bmp_initial_pos 0x%llx, "
"zone_start 0x%llx, zone_end 0x%llx.",
search_zone, pass,
(unsigned long long)bmp_initial_pos,
(unsigned long long)zone_start,
(unsigned long long)zone_end);
bmp_pos = zone_start;
if (zone_start == zone_end) {
ntfs_debug("Empty zone, going to "
"done_zones_check.");
/* Empty zone. Don't bother searching it. */
goto done_zones_check;
}
ntfs_debug("Continuing outer while loop.");
continue;
} /* done_zones == 7 */
ntfs_debug("All zones are finished.");
/*
* All zones are finished! If DATA_ZONE, shrink mft zone. If
* MFT_ZONE, we have really run out of space.
*/
mft_zone_size = vol->mft_zone_end - vol->mft_zone_start;
ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end "
"0x%llx, mft_zone_size 0x%llx.",
(unsigned long long)vol->mft_zone_start,
(unsigned long long)vol->mft_zone_end,
(unsigned long long)mft_zone_size);
if (zone == MFT_ZONE || mft_zone_size <= 0) {
ntfs_debug("No free clusters left, going to out.");
/* Really no more space left on device. */
err = -ENOSPC;
goto out;
} /* zone == DATA_ZONE && mft_zone_size > 0 */
ntfs_debug("Shrinking mft zone.");
zone_end = vol->mft_zone_end;
mft_zone_size >>= 1;
if (mft_zone_size > 0)
vol->mft_zone_end = vol->mft_zone_start + mft_zone_size;
else /* mft zone and data2 zone no longer exist. */
vol->data2_zone_pos = vol->mft_zone_start =
vol->mft_zone_end = 0;
if (vol->mft_zone_pos >= vol->mft_zone_end) {
vol->mft_zone_pos = vol->mft_lcn;
if (!vol->mft_zone_end)
vol->mft_zone_pos = 0;
}
bmp_pos = zone_start = bmp_initial_pos =
vol->data1_zone_pos = vol->mft_zone_end;
search_zone = 2;
pass = 2;
done_zones &= ~2;
ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, "
"vol->mft_zone_start 0x%llx, "
"vol->mft_zone_end 0x%llx, "
"vol->mft_zone_pos 0x%llx, search_zone 2, "
"pass 2, dones_zones 0x%x, zone_start 0x%llx, "
"zone_end 0x%llx, vol->data1_zone_pos 0x%llx, "
"continuing outer while loop.",
(unsigned long long)mft_zone_size,
(unsigned long long)vol->mft_zone_start,
(unsigned long long)vol->mft_zone_end,
(unsigned long long)vol->mft_zone_pos,
done_zones, (unsigned long long)zone_start,
(unsigned long long)zone_end,
(unsigned long long)vol->data1_zone_pos);
}
ntfs_debug("After outer while loop.");
out:
ntfs_debug("At out.");
/* Add runlist terminator element. */
if (likely(rl)) {
rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
rl[rlpos].lcn = is_extension ? LCN_ENOENT : LCN_RL_NOT_MAPPED;
rl[rlpos].length = 0;
}
if (likely(page && !IS_ERR(page))) {
if (need_writeback) {
ntfs_debug("Marking page dirty.");
flush_dcache_page(page);
set_page_dirty(page);
need_writeback = 0;
}
ntfs_unmap_page(page);
}
if (likely(!err)) {
up_write(&vol->lcnbmp_lock);
ntfs_debug("Done.");
return rl;
}
ntfs_error(vol->sb, "Failed to allocate clusters, aborting "
"(error %i).", err);
if (rl) {
int err2;
if (err == -ENOSPC)
ntfs_debug("Not enough space to complete allocation, "
"err -ENOSPC, first free lcn 0x%llx, "
"could allocate up to 0x%llx "
"clusters.",
(unsigned long long)rl[0].lcn,
(unsigned long long)(count - clusters));
/* Deallocate all allocated clusters. */
ntfs_debug("Attempting rollback...");
err2 = ntfs_cluster_free_from_rl_nolock(vol, rl);
if (err2) {
ntfs_error(vol->sb, "Failed to rollback (error %i). "
"Leaving inconsistent metadata! "
"Unmount and run chkdsk.", err2);
NVolSetErrors(vol);
}
/* Free the runlist. */
ntfs_free(rl);
} else if (err == -ENOSPC)
ntfs_debug("No space left at all, err = -ENOSPC, first free "
"lcn = 0x%llx.",
(long long)vol->data1_zone_pos);
up_write(&vol->lcnbmp_lock);
return ERR_PTR(err);
}
/**
* __ntfs_cluster_free - free clusters on an ntfs volume
* @ni: ntfs inode whose runlist describes the clusters to free
* @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
* @count: number of clusters to free or -1 for all clusters
* @ctx: active attribute search context if present or NULL if not
* @is_rollback: true if this is a rollback operation
*
* Free @count clusters starting at the cluster @start_vcn in the runlist
* described by the vfs inode @ni.
*
* If @count is -1, all clusters from @start_vcn to the end of the runlist are
* deallocated. Thus, to completely free all clusters in a runlist, use
* @start_vcn = 0 and @count = -1.
*
* If @ctx is specified, it is an active search context of @ni and its base mft
* record. This is needed when __ntfs_cluster_free() encounters unmapped
* runlist fragments and allows their mapping. If you do not have the mft
* record mapped, you can specify @ctx as NULL and __ntfs_cluster_free() will
* perform the necessary mapping and unmapping.
*
* Note, __ntfs_cluster_free() saves the state of @ctx on entry and restores it
* before returning. Thus, @ctx will be left pointing to the same attribute on
* return as on entry. However, the actual pointers in @ctx may point to
* different memory locations on return, so you must remember to reset any
* cached pointers from the @ctx, i.e. after the call to __ntfs_cluster_free(),
* you will probably want to do:
* m = ctx->mrec;
* a = ctx->attr;
* Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
* you cache ctx->mrec in a variable @m of type MFT_RECORD *.
*
* @is_rollback should always be 'false', it is for internal use to rollback
* errors. You probably want to use ntfs_cluster_free() instead.
*
* Note, __ntfs_cluster_free() does not modify the runlist, so you have to
* remove from the runlist or mark sparse the freed runs later.
*
* Return the number of deallocated clusters (not counting sparse ones) on
* success and -errno on error.
*
* WARNING: If @ctx is supplied, regardless of whether success or failure is
* returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
* is no longer valid, i.e. you need to either call
* ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
* In that case PTR_ERR(@ctx->mrec) will give you the error code for
* why the mapping of the old inode failed.
*
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist may be modified when
* needed runlist fragments need to be mapped.
* - The volume lcn bitmap must be unlocked on entry and is unlocked
* on return.
* - This function takes the volume lcn bitmap lock for writing and
* modifies the bitmap contents.
* - If @ctx is NULL, the base mft record of @ni must not be mapped on
* entry and it will be left unmapped on return.
* - If @ctx is not NULL, the base mft record must be mapped on entry
* and it will be left mapped on return.
*/
s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
ntfs_attr_search_ctx *ctx, const bool is_rollback)
{
s64 delta, to_free, total_freed, real_freed;
ntfs_volume *vol;
struct inode *lcnbmp_vi;
runlist_element *rl;
int err;
BUG_ON(!ni);
ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count "
"0x%llx.%s", ni->mft_no, (unsigned long long)start_vcn,
(unsigned long long)count,
is_rollback ? " (rollback)" : "");
vol = ni->vol;
lcnbmp_vi = vol->lcnbmp_ino;
BUG_ON(!lcnbmp_vi);
BUG_ON(start_vcn < 0);
BUG_ON(count < -1);
/*
* Lock the lcn bitmap for writing but only if not rolling back. We
* must hold the lock all the way including through rollback otherwise
* rollback is not possible because once we have cleared a bit and
* dropped the lock, anyone could have set the bit again, thus
* allocating the cluster for another use.
*/
if (likely(!is_rollback))
down_write(&vol->lcnbmp_lock);
total_freed = real_freed = 0;
rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx);
if (IS_ERR(rl)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to find first runlist "
"element (error %li), aborting.",
PTR_ERR(rl));
err = PTR_ERR(rl);
goto err_out;
}
if (unlikely(rl->lcn < LCN_HOLE)) {
if (!is_rollback)
ntfs_error(vol->sb, "First runlist element has "
"invalid lcn, aborting.");
err = -EIO;
goto err_out;
}
/* 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 (likely(rl->lcn >= 0)) {
/* Do the actual freeing of the clusters in this run. */
err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta,
to_free, likely(!is_rollback) ? 0 : 1);
if (unlikely(err)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to clear first run "
"(error %i), aborting.", err);
goto err_out;
}
/* We have freed @to_free real clusters. */
real_freed = to_free;
};
/* Go to the next run and adjust the number of clusters left to free. */
++rl;
if (count >= 0)
count -= to_free;
/* Keep track of the total "freed" clusters, including sparse ones. */
total_freed = to_free;
/*
* Loop over the remaining runs, using @count as a capping value, and
* free them.
*/
for (; rl->length && count != 0; ++rl) {
if (unlikely(rl->lcn < LCN_HOLE)) {
VCN vcn;
/* Attempt to map runlist. */
vcn = rl->vcn;
rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx);
if (IS_ERR(rl)) {
err = PTR_ERR(rl);
if (!is_rollback)
ntfs_error(vol->sb, "Failed to map "
"runlist fragment or "
"failed to find "
"subsequent runlist "
"element.");
goto err_out;
}
if (unlikely(rl->lcn < LCN_HOLE)) {
if (!is_rollback)
ntfs_error(vol->sb, "Runlist element "
"has invalid lcn "
"(0x%llx).",
(unsigned long long)
rl->lcn);
err = -EIO;
goto err_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 (likely(rl->lcn >= 0)) {
/* Do the actual freeing of the clusters in the run. */
err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn,
to_free, likely(!is_rollback) ? 0 : 1);
if (unlikely(err)) {
if (!is_rollback)
ntfs_error(vol->sb, "Failed to clear "
"subsequent run.");
goto err_out;
}
/* We have freed @to_free real clusters. */
real_freed += to_free;
}
/* Adjust the number of clusters left to free. */
if (count >= 0)
count -= to_free;
/* Update the total done clusters. */
total_freed += to_free;
}
if (likely(!is_rollback))
up_write(&vol->lcnbmp_lock);
BUG_ON(count > 0);
/* We are done. Return the number of actually freed clusters. */
ntfs_debug("Done.");
return real_freed;
err_out:
if (is_rollback)
return err;
/* If no real clusters were freed, no need to rollback. */
if (!real_freed) {
up_write(&vol->lcnbmp_lock);
return err;
}
/*
* Attempt to rollback and if that succeeds just return the error code.
* If rollback fails, set the volume errors flag, emit an error
* message, and return the error code.
*/
delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, true);
if (delta < 0) {
ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving "
"inconsistent metadata! Unmount and run "
"chkdsk.", (int)delta);
NVolSetErrors(vol);
}
up_write(&vol->lcnbmp_lock);
ntfs_error(vol->sb, "Aborting (error %i).", err);
return err;
}
#endif /* NTFS_RW */