fs/ntfs3: Add file operations and implementation

This adds file operations and implementation

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

1 files changed, 1111 insertions, 0 deletions

diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c
new file mode 100644
index 000000000000..5cdf6efe67e0
--- /dev/null
+++ b/fs/ntfs3/run.c
@@ -0,0 +1,1111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
+ *
+ * TODO: try to use extents tree (instead of array)
+ */
+
+#include <linux/blkdev.h>
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+#include <linux/nls.h>
+
+#include "debug.h"
+#include "ntfs.h"
+#include "ntfs_fs.h"
+
+/* runs_tree is a continues memory. Try to avoid big size  */
+#define NTFS3_RUN_MAX_BYTES 0x10000
+
+struct ntfs_run {
+	CLST vcn; /* virtual cluster number */
+	CLST len; /* length in clusters */
+	CLST lcn; /* logical cluster number */
+};
+
+/*
+ * run_lookup
+ *
+ * Lookup the index of a MCB entry that is first <= vcn.
+ * case of success it will return non-zero value and set
+ * 'index' parameter to index of entry been found.
+ * case of entry missing from list 'index' will be set to
+ * point to insertion position for the entry question.
+ */
+bool run_lookup(const struct runs_tree *run, CLST vcn, size_t *index)
+{
+	size_t min_idx, max_idx, mid_idx;
+	struct ntfs_run *r;
+
+	if (!run->count) {
+		*index = 0;
+		return false;
+	}
+
+	min_idx = 0;
+	max_idx = run->count - 1;
+
+	/* Check boundary cases specially, 'cause they cover the often requests */
+	r = run->runs;
+	if (vcn < r->vcn) {
+		*index = 0;
+		return false;
+	}
+
+	if (vcn < r->vcn + r->len) {
+		*index = 0;
+		return true;
+	}
+
+	r += max_idx;
+	if (vcn >= r->vcn + r->len) {
+		*index = run->count;
+		return false;
+	}
+
+	if (vcn >= r->vcn) {
+		*index = max_idx;
+		return true;
+	}
+
+	do {
+		mid_idx = min_idx + ((max_idx - min_idx) >> 1);
+		r = run->runs + mid_idx;
+
+		if (vcn < r->vcn) {
+			max_idx = mid_idx - 1;
+			if (!mid_idx)
+				break;
+		} else if (vcn >= r->vcn + r->len) {
+			min_idx = mid_idx + 1;
+		} else {
+			*index = mid_idx;
+			return true;
+		}
+	} while (min_idx <= max_idx);
+
+	*index = max_idx + 1;
+	return false;
+}
+
+/*
+ * run_consolidate
+ *
+ * consolidate runs starting from a given one.
+ */
+static void run_consolidate(struct runs_tree *run, size_t index)
+{
+	size_t i;
+	struct ntfs_run *r = run->runs + index;
+
+	while (index + 1 < run->count) {
+		/*
+		 * I should merge current run with next
+		 * if start of the next run lies inside one being tested.
+		 */
+		struct ntfs_run *n = r + 1;
+		CLST end = r->vcn + r->len;
+		CLST dl;
+
+		/* Stop if runs are not aligned one to another. */
+		if (n->vcn > end)
+			break;
+
+		dl = end - n->vcn;
+
+		/*
+		 * If range at index overlaps with next one
+		 * then I will either adjust it's start position
+		 * or (if completely matches) dust remove one from the list.
+		 */
+		if (dl > 0) {
+			if (n->len <= dl)
+				goto remove_next_range;
+
+			n->len -= dl;
+			n->vcn += dl;
+			if (n->lcn != SPARSE_LCN)
+				n->lcn += dl;
+			dl = 0;
+		}
+
+		/*
+		 * Stop if sparse mode does not match
+		 * both current and next runs.
+		 */
+		if ((n->lcn == SPARSE_LCN) != (r->lcn == SPARSE_LCN)) {
+			index += 1;
+			r = n;
+			continue;
+		}
+
+		/*
+		 * Check if volume block
+		 * of a next run lcn does not match
+		 * last volume block of the current run.
+		 */
+		if (n->lcn != SPARSE_LCN && n->lcn != r->lcn + r->len)
+			break;
+
+		/*
+		 * Next and current are siblings.
+		 * Eat/join.
+		 */
+		r->len += n->len - dl;
+
+remove_next_range:
+		i = run->count - (index + 1);
+		if (i > 1)
+			memmove(n, n + 1, sizeof(*n) * (i - 1));
+
+		run->count -= 1;
+	}
+}
+
+/* returns true if range [svcn - evcn] is mapped*/
+bool run_is_mapped_full(const struct runs_tree *run, CLST svcn, CLST evcn)
+{
+	size_t i;
+	const struct ntfs_run *r, *end;
+	CLST next_vcn;
+
+	if (!run_lookup(run, svcn, &i))
+		return false;
+
+	end = run->runs + run->count;
+	r = run->runs + i;
+
+	for (;;) {
+		next_vcn = r->vcn + r->len;
+		if (next_vcn > evcn)
+			return true;
+
+		if (++r >= end)
+			return false;
+
+		if (r->vcn != next_vcn)
+			return false;
+	}
+}
+
+bool run_lookup_entry(const struct runs_tree *run, CLST vcn, CLST *lcn,
+		      CLST *len, size_t *index)
+{
+	size_t idx;
+	CLST gap;
+	struct ntfs_run *r;
+
+	/* Fail immediately if nrun was not touched yet. */
+	if (!run->runs)
+		return false;
+
+	if (!run_lookup(run, vcn, &idx))
+		return false;
+
+	r = run->runs + idx;
+
+	if (vcn >= r->vcn + r->len)
+		return false;
+
+	gap = vcn - r->vcn;
+	if (r->len <= gap)
+		return false;
+
+	*lcn = r->lcn == SPARSE_LCN ? SPARSE_LCN : (r->lcn + gap);
+
+	if (len)
+		*len = r->len - gap;
+	if (index)
+		*index = idx;
+
+	return true;
+}
+
+/*
+ * run_truncate_head
+ *
+ * decommit the range before vcn
+ */
+void run_truncate_head(struct runs_tree *run, CLST vcn)
+{
+	size_t index;
+	struct ntfs_run *r;
+
+	if (run_lookup(run, vcn, &index)) {
+		r = run->runs + index;
+
+		if (vcn > r->vcn) {
+			CLST dlen = vcn - r->vcn;
+
+			r->vcn = vcn;
+			r->len -= dlen;
+			if (r->lcn != SPARSE_LCN)
+				r->lcn += dlen;
+		}
+
+		if (!index)
+			return;
+	}
+	r = run->runs;
+	memmove(r, r + index, sizeof(*r) * (run->count - index));
+
+	run->count -= index;
+
+	if (!run->count) {
+		ntfs_vfree(run->runs);
+		run->runs = NULL;
+		run->allocated = 0;
+	}
+}
+
+/*
+ * run_truncate
+ *
+ * decommit the range after vcn
+ */
+void run_truncate(struct runs_tree *run, CLST vcn)
+{
+	size_t index;
+
+	/*
+	 * If I hit the range then
+	 * I have to truncate one.
+	 * If range to be truncated is becoming empty
+	 * then it will entirely be removed.
+	 */
+	if (run_lookup(run, vcn, &index)) {
+		struct ntfs_run *r = run->runs + index;
+
+		r->len = vcn - r->vcn;
+
+		if (r->len > 0)
+			index += 1;
+	}
+
+	/*
+	 * At this point 'index' is set to
+	 * position that should be thrown away (including index itself)
+	 * Simple one - just set the limit.
+	 */
+	run->count = index;
+
+	/* Do not reallocate array 'runs'. Only free if possible */
+	if (!index) {
+		ntfs_vfree(run->runs);
+		run->runs = NULL;
+		run->allocated = 0;
+	}
+}
+
+/* trim head and tail if necessary*/
+void run_truncate_around(struct runs_tree *run, CLST vcn)
+{
+	run_truncate_head(run, vcn);
+
+	if (run->count >= NTFS3_RUN_MAX_BYTES / sizeof(struct ntfs_run) / 2)
+		run_truncate(run, (run->runs + (run->count >> 1))->vcn);
+}
+
+/*
+ * run_add_entry
+ *
+ * sets location to known state.
+ * run to be added may overlap with existing location.
+ * returns false if of memory
+ */
+bool run_add_entry(struct runs_tree *run, CLST vcn, CLST lcn, CLST len,
+		   bool is_mft)
+{
+	size_t used, index;
+	struct ntfs_run *r;
+	bool inrange;
+	CLST tail_vcn = 0, tail_len = 0, tail_lcn = 0;
+	bool should_add_tail = false;
+
+	/*
+	 * Lookup the insertion point.
+	 *
+	 * Execute bsearch for the entry containing
+	 * start position question.
+	 */
+	inrange = run_lookup(run, vcn, &index);
+
+	/*
+	 * Shortcut here would be case of
+	 * range not been found but one been added
+	 * continues previous run.
+	 * this case I can directly make use of
+	 * existing range as my start point.
+	 */
+	if (!inrange && index > 0) {
+		struct ntfs_run *t = run->runs + index - 1;
+
+		if (t->vcn + t->len == vcn &&
+		    (t->lcn == SPARSE_LCN) == (lcn == SPARSE_LCN) &&
+		    (lcn == SPARSE_LCN || lcn == t->lcn + t->len)) {
+			inrange = true;
+			index -= 1;
+		}
+	}
+
+	/*
+	 * At this point 'index' either points to the range
+	 * containing start position or to the insertion position
+	 * for a new range.
+	 * So first let's check if range I'm probing is here already.
+	 */
+	if (!inrange) {
+requires_new_range:
+		/*
+		 * Range was not found.
+		 * Insert at position 'index'
+		 */
+		used = run->count * sizeof(struct ntfs_run);
+
+		/*
+		 * Check allocated space.
+		 * If one is not enough to get one more entry
+		 * then it will be reallocated
+		 */
+		if (run->allocated < used + sizeof(struct ntfs_run)) {
+			size_t bytes;
+			struct ntfs_run *new_ptr;
+
+			/* Use power of 2 for 'bytes'*/
+			if (!used) {
+				bytes = 64;
+			} else if (used <= 16 * PAGE_SIZE) {
+				if (is_power_of2(run->allocated))
+					bytes = run->allocated << 1;
+				else
+					bytes = (size_t)1
+						<< (2 + blksize_bits(used));
+			} else {
+				bytes = run->allocated + (16 * PAGE_SIZE);
+			}
+
+			WARN_ON(!is_mft && bytes > NTFS3_RUN_MAX_BYTES);
+
+			new_ptr = ntfs_vmalloc(bytes);
+
+			if (!new_ptr)
+				return false;
+
+			r = new_ptr + index;
+			memcpy(new_ptr, run->runs,
+			       index * sizeof(struct ntfs_run));
+			memcpy(r + 1, run->runs + index,
+			       sizeof(struct ntfs_run) * (run->count - index));
+
+			ntfs_vfree(run->runs);
+			run->runs = new_ptr;
+			run->allocated = bytes;
+
+		} else {
+			size_t i = run->count - index;
+
+			r = run->runs + index;
+
+			/* memmove appears to be a bottle neck here... */
+			if (i > 0)
+				memmove(r + 1, r, sizeof(struct ntfs_run) * i);
+		}
+
+		r->vcn = vcn;
+		r->lcn = lcn;
+		r->len = len;
+		run->count += 1;
+	} else {
+		r = run->runs + index;
+
+		/*
+		 * If one of ranges was not allocated
+		 * then I have to split location I just matched.
+		 * and insert current one
+		 * a common case this requires tail to be reinserted
+		 * a recursive call.
+		 */
+		if (((lcn == SPARSE_LCN) != (r->lcn == SPARSE_LCN)) ||
+		    (lcn != SPARSE_LCN && lcn != r->lcn + (vcn - r->vcn))) {
+			CLST to_eat = vcn - r->vcn;
+			CLST Tovcn = to_eat + len;
+
+			should_add_tail = Tovcn < r->len;
+
+			if (should_add_tail) {
+				tail_lcn = r->lcn == SPARSE_LCN
+						   ? SPARSE_LCN
+						   : (r->lcn + Tovcn);
+				tail_vcn = r->vcn + Tovcn;
+				tail_len = r->len - Tovcn;
+			}
+
+			if (to_eat > 0) {
+				r->len = to_eat;
+				inrange = false;
+				index += 1;
+				goto requires_new_range;
+			}
+
+			/* lcn should match one I'm going to add. */
+			r->lcn = lcn;
+		}
+
+		/*
+		 * If existing range fits then I'm done.
+		 * Otherwise extend found one and fall back to range jocode.
+		 */
+		if (r->vcn + r->len < vcn + len)
+			r->len += len - ((r->vcn + r->len) - vcn);
+	}
+
+	/*
+	 * And normalize it starting from insertion point.
+	 * It's possible that no insertion needed case if
+	 * start point lies within the range of an entry
+	 * that 'index' points to.
+	 */
+	if (inrange && index > 0)
+		index -= 1;
+	run_consolidate(run, index);
+	run_consolidate(run, index + 1);
+
+	/*
+	 * a special case
+	 * I have to add extra range a tail.
+	 */
+	if (should_add_tail &&
+	    !run_add_entry(run, tail_vcn, tail_lcn, tail_len, is_mft))
+		return false;
+
+	return true;
+}
+
+/*helper for attr_collapse_range, which is helper for fallocate(collapse_range)*/
+bool run_collapse_range(struct runs_tree *run, CLST vcn, CLST len)
+{
+	size_t index, eat;
+	struct ntfs_run *r, *e, *eat_start, *eat_end;
+	CLST end;
+
+	if (WARN_ON(!run_lookup(run, vcn, &index)))
+		return true; /* should never be here */
+
+	e = run->runs + run->count;
+	r = run->runs + index;
+	end = vcn + len;
+
+	if (vcn > r->vcn) {
+		if (r->vcn + r->len <= end) {
+			/* collapse tail of run */
+			r->len = vcn - r->vcn;
+		} else if (r->lcn == SPARSE_LCN) {
+			/* collapse a middle part of sparsed run */
+			r->len -= len;
+		} else {
+			/* collapse a middle part of normal run, split */
+			if (!run_add_entry(run, vcn, SPARSE_LCN, len, false))
+				return false;
+			return run_collapse_range(run, vcn, len);
+		}
+
+		r += 1;
+	}
+
+	eat_start = r;
+	eat_end = r;
+
+	for (; r < e; r++) {
+		CLST d;
+
+		if (r->vcn >= end) {
+			r->vcn -= len;
+			continue;
+		}
+
+		if (r->vcn + r->len <= end) {
+			/* eat this run */
+			eat_end = r + 1;
+			continue;
+		}
+
+		d = end - r->vcn;
+		if (r->lcn != SPARSE_LCN)
+			r->lcn += d;
+		r->len -= d;
+		r->vcn -= len - d;
+	}
+
+	eat = eat_end - eat_start;
+	memmove(eat_start, eat_end, (e - eat_end) * sizeof(*r));
+	run->count -= eat;
+
+	return true;
+}
+
+/*
+ * run_get_entry
+ *
+ * returns index-th mapped region
+ */
+bool run_get_entry(const struct runs_tree *run, size_t index, CLST *vcn,
+		   CLST *lcn, CLST *len)
+{
+	const struct ntfs_run *r;
+
+	if (index >= run->count)
+		return false;
+
+	r = run->runs + index;
+
+	if (!r->len)
+		return false;
+
+	if (vcn)
+		*vcn = r->vcn;
+	if (lcn)
+		*lcn = r->lcn;
+	if (len)
+		*len = r->len;
+	return true;
+}
+
+/*
+ * run_packed_size
+ *
+ * calculates the size of packed int64
+ */
+#ifdef __BIG_ENDIAN
+static inline int run_packed_size(const s64 n)
+{
+	const u8 *p = (const u8 *)&n + sizeof(n) - 1;
+
+	if (n >= 0) {
+		if (p[-7] || p[-6] || p[-5] || p[-4])
+			p -= 4;
+		if (p[-3] || p[-2])
+			p -= 2;
+		if (p[-1])
+			p -= 1;
+		if (p[0] & 0x80)
+			p -= 1;
+	} else {
+		if (p[-7] != 0xff || p[-6] != 0xff || p[-5] != 0xff ||
+		    p[-4] != 0xff)
+			p -= 4;
+		if (p[-3] != 0xff || p[-2] != 0xff)
+			p -= 2;
+		if (p[-1] != 0xff)
+			p -= 1;
+		if (!(p[0] & 0x80))
+			p -= 1;
+	}
+	return (const u8 *)&n + sizeof(n) - p;
+}
+
+/* full trusted function. It does not check 'size' for errors */
+static inline void run_pack_s64(u8 *run_buf, u8 size, s64 v)
+{
+	const u8 *p = (u8 *)&v;
+
+	switch (size) {
+	case 8:
+		run_buf[7] = p[0];
+		fallthrough;
+	case 7:
+		run_buf[6] = p[1];
+		fallthrough;
+	case 6:
+		run_buf[5] = p[2];
+		fallthrough;
+	case 5:
+		run_buf[4] = p[3];
+		fallthrough;
+	case 4:
+		run_buf[3] = p[4];
+		fallthrough;
+	case 3:
+		run_buf[2] = p[5];
+		fallthrough;
+	case 2:
+		run_buf[1] = p[6];
+		fallthrough;
+	case 1:
+		run_buf[0] = p[7];
+	}
+}
+
+/* full trusted function. It does not check 'size' for errors */
+static inline s64 run_unpack_s64(const u8 *run_buf, u8 size, s64 v)
+{
+	u8 *p = (u8 *)&v;
+
+	switch (size) {
+	case 8:
+		p[0] = run_buf[7];
+		fallthrough;
+	case 7:
+		p[1] = run_buf[6];
+		fallthrough;
+	case 6:
+		p[2] = run_buf[5];
+		fallthrough;
+	case 5:
+		p[3] = run_buf[4];
+		fallthrough;
+	case 4:
+		p[4] = run_buf[3];
+		fallthrough;
+	case 3:
+		p[5] = run_buf[2];
+		fallthrough;
+	case 2:
+		p[6] = run_buf[1];
+		fallthrough;
+	case 1:
+		p[7] = run_buf[0];
+	}
+	return v;
+}
+
+#else
+
+static inline int run_packed_size(const s64 n)
+{
+	const u8 *p = (const u8 *)&n;
+
+	if (n >= 0) {
+		if (p[7] || p[6] || p[5] || p[4])
+			p += 4;
+		if (p[3] || p[2])
+			p += 2;
+		if (p[1])
+			p += 1;
+		if (p[0] & 0x80)
+			p += 1;
+	} else {
+		if (p[7] != 0xff || p[6] != 0xff || p[5] != 0xff ||
+		    p[4] != 0xff)
+			p += 4;
+		if (p[3] != 0xff || p[2] != 0xff)
+			p += 2;
+		if (p[1] != 0xff)
+			p += 1;
+		if (!(p[0] & 0x80))
+			p += 1;
+	}
+
+	return 1 + p - (const u8 *)&n;
+}
+
+/* full trusted function. It does not check 'size' for errors */
+static inline void run_pack_s64(u8 *run_buf, u8 size, s64 v)
+{
+	const u8 *p = (u8 *)&v;
+
+	/* memcpy( run_buf, &v, size); is it faster? */
+	switch (size) {
+	case 8:
+		run_buf[7] = p[7];
+		fallthrough;
+	case 7:
+		run_buf[6] = p[6];
+		fallthrough;
+	case 6:
+		run_buf[5] = p[5];
+		fallthrough;
+	case 5:
+		run_buf[4] = p[4];
+		fallthrough;
+	case 4:
+		run_buf[3] = p[3];
+		fallthrough;
+	case 3:
+		run_buf[2] = p[2];
+		fallthrough;
+	case 2:
+		run_buf[1] = p[1];
+		fallthrough;
+	case 1:
+		run_buf[0] = p[0];
+	}
+}
+
+/* full trusted function. It does not check 'size' for errors */
+static inline s64 run_unpack_s64(const u8 *run_buf, u8 size, s64 v)
+{
+	u8 *p = (u8 *)&v;
+
+	/* memcpy( &v, run_buf, size); is it faster? */
+	switch (size) {
+	case 8:
+		p[7] = run_buf[7];
+		fallthrough;
+	case 7:
+		p[6] = run_buf[6];
+		fallthrough;
+	case 6:
+		p[5] = run_buf[5];
+		fallthrough;
+	case 5:
+		p[4] = run_buf[4];
+		fallthrough;
+	case 4:
+		p[3] = run_buf[3];
+		fallthrough;
+	case 3:
+		p[2] = run_buf[2];
+		fallthrough;
+	case 2:
+		p[1] = run_buf[1];
+		fallthrough;
+	case 1:
+		p[0] = run_buf[0];
+	}
+	return v;
+}
+#endif
+
+/*
+ * run_pack
+ *
+ * packs runs into buffer
+ * packed_vcns - how much runs we have packed
+ * packed_size - how much bytes we have used run_buf
+ */
+int run_pack(const struct runs_tree *run, CLST svcn, CLST len, u8 *run_buf,
+	     u32 run_buf_size, CLST *packed_vcns)
+{
+	CLST next_vcn, vcn, lcn;
+	CLST prev_lcn = 0;
+	CLST evcn1 = svcn + len;
+	int packed_size = 0;
+	size_t i;
+	bool ok;
+	s64 dlcn;
+	int offset_size, size_size, tmp;
+
+	next_vcn = vcn = svcn;
+
+	*packed_vcns = 0;
+
+	if (!len)
+		goto out;
+
+	ok = run_lookup_entry(run, vcn, &lcn, &len, &i);
+
+	if (!ok)
+		goto error;
+
+	if (next_vcn != vcn)
+		goto error;
+
+	for (;;) {
+		next_vcn = vcn + len;
+		if (next_vcn > evcn1)
+			len = evcn1 - vcn;
+
+		/* how much bytes required to pack len */
+		size_size = run_packed_size(len);
+
+		/* offset_size - how much bytes is packed dlcn */
+		if (lcn == SPARSE_LCN) {
+			offset_size = 0;
+			dlcn = 0;
+		} else {
+			/* NOTE: lcn can be less than prev_lcn! */
+			dlcn = (s64)lcn - prev_lcn;
+			offset_size = run_packed_size(dlcn);
+			prev_lcn = lcn;
+		}
+
+		tmp = run_buf_size - packed_size - 2 - offset_size;
+		if (tmp <= 0)
+			goto out;
+
+		/* can we store this entire run */
+		if (tmp < size_size)
+			goto out;
+
+		if (run_buf) {
+			/* pack run header */
+			run_buf[0] = ((u8)(size_size | (offset_size << 4)));
+			run_buf += 1;
+
+			/* Pack the length of run */
+			run_pack_s64(run_buf, size_size, len);
+
+			run_buf += size_size;
+			/* Pack the offset from previous lcn */
+			run_pack_s64(run_buf, offset_size, dlcn);
+			run_buf += offset_size;
+		}
+
+		packed_size += 1 + offset_size + size_size;
+		*packed_vcns += len;
+
+		if (packed_size + 1 >= run_buf_size || next_vcn >= evcn1)
+			goto out;
+
+		ok = run_get_entry(run, ++i, &vcn, &lcn, &len);
+		if (!ok)
+			goto error;
+
+		if (next_vcn != vcn)
+			goto error;
+	}
+
+out:
+	/* Store last zero */
+	if (run_buf)
+		run_buf[0] = 0;
+
+	return packed_size + 1;
+
+error:
+	return -EOPNOTSUPP;
+}
+
+/*
+ * run_unpack
+ *
+ * unpacks packed runs from "run_buf"
+ * returns error, if negative, or real used bytes
+ */
+int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
+	       CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
+	       u32 run_buf_size)
+{
+	u64 prev_lcn, vcn64, lcn, next_vcn;
+	const u8 *run_last, *run_0;
+	bool is_mft = ino == MFT_REC_MFT;
+
+	/* Check for empty */
+	if (evcn + 1 == svcn)
+		return 0;
+
+	if (evcn < svcn)
+		return -EINVAL;
+
+	run_0 = run_buf;
+	run_last = run_buf + run_buf_size;
+	prev_lcn = 0;
+	vcn64 = svcn;
+
+	/* Read all runs the chain */
+	/* size_size - how much bytes is packed len */
+	while (run_buf < run_last) {
+		/* size_size - how much bytes is packed len */
+		u8 size_size = *run_buf & 0xF;
+		/* offset_size - how much bytes is packed dlcn */
+		u8 offset_size = *run_buf++ >> 4;
+		u64 len;
+
+		if (!size_size)
+			break;
+
+		/*
+		 * Unpack runs.
+		 * NOTE: runs are stored little endian order
+		 * "len" is unsigned value, "dlcn" is signed
+		 * Large positive number requires to store 5 bytes
+		 * e.g.: 05 FF 7E FF FF 00 00 00
+		 */
+		if (size_size > 8)
+			return -EINVAL;
+
+		len = run_unpack_s64(run_buf, size_size, 0);
+		/* skip size_size */
+		run_buf += size_size;
+
+		if (!len)
+			return -EINVAL;
+
+		if (!offset_size)
+			lcn = SPARSE_LCN64;
+		else if (offset_size <= 8) {
+			s64 dlcn;
+
+			/* initial value of dlcn is -1 or 0 */
+			dlcn = (run_buf[offset_size - 1] & 0x80) ? (s64)-1 : 0;
+			dlcn = run_unpack_s64(run_buf, offset_size, dlcn);
+			/* skip offset_size */
+			run_buf += offset_size;
+
+			if (!dlcn)
+				return -EINVAL;
+			lcn = prev_lcn + dlcn;
+			prev_lcn = lcn;
+		} else
+			return -EINVAL;
+
+		next_vcn = vcn64 + len;
+		/* check boundary */
+		if (next_vcn > evcn + 1)
+			return -EINVAL;
+
+#ifndef CONFIG_NTFS3_64BIT_CLUSTER
+		if (next_vcn > 0x100000000ull || (lcn + len) > 0x100000000ull) {
+			ntfs_err(
+				sbi->sb,
+				"This driver is compiled whitout CONFIG_NTFS3_64BIT_CLUSTER (like windows driver).\n"
+				"Volume contains 64 bits run: vcn %llx, lcn %llx, len %llx.\n"
+				"Activate CONFIG_NTFS3_64BIT_CLUSTER to process this case",
+				vcn64, lcn, len);
+			return -EOPNOTSUPP;
+		}
+#endif
+		if (lcn != SPARSE_LCN64 && lcn + len > sbi->used.bitmap.nbits) {
+			/* lcn range is out of volume */
+			return -EINVAL;
+		}
+
+		if (!run)
+			; /* called from check_attr(fslog.c) to check run */
+		else if (run == RUN_DEALLOCATE) {
+			/* called from ni_delete_all to free clusters without storing in run */
+			if (lcn != SPARSE_LCN64)
+				mark_as_free_ex(sbi, lcn, len, true);
+		} else if (vcn64 >= vcn) {
+			if (!run_add_entry(run, vcn64, lcn, len, is_mft))
+				return -ENOMEM;
+		} else if (next_vcn > vcn) {
+			u64 dlen = vcn - vcn64;
+
+			if (!run_add_entry(run, vcn, lcn + dlen, len - dlen,
+					   is_mft))
+				return -ENOMEM;
+		}
+
+		vcn64 = next_vcn;
+	}
+
+	if (vcn64 != evcn + 1) {
+		/* not expected length of unpacked runs */
+		return -EINVAL;
+	}
+
+	return run_buf - run_0;
+}
+
+#ifdef NTFS3_CHECK_FREE_CLST
+/*
+ * run_unpack_ex
+ *
+ * unpacks packed runs from "run_buf"
+ * checks unpacked runs to be used in bitmap
+ * returns error, if negative, or real used bytes
+ */
+int run_unpack_ex(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino,
+		  CLST svcn, CLST evcn, CLST vcn, const u8 *run_buf,
+		  u32 run_buf_size)
+{
+	int ret, err;
+	CLST next_vcn, lcn, len;
+	size_t index;
+	bool ok;
+	struct wnd_bitmap *wnd;
+
+	ret = run_unpack(run, sbi, ino, svcn, evcn, vcn, run_buf, run_buf_size);
+	if (ret <= 0)
+		return ret;
+
+	if (!sbi->used.bitmap.sb || !run || run == RUN_DEALLOCATE)
+		return ret;
+
+	if (ino == MFT_REC_BADCLUST)
+		return ret;
+
+	next_vcn = vcn = svcn;
+	wnd = &sbi->used.bitmap;
+
+	for (ok = run_lookup_entry(run, vcn, &lcn, &len, &index);
+	     next_vcn <= evcn;
+	     ok = run_get_entry(run, ++index, &vcn, &lcn, &len)) {
+		if (!ok || next_vcn != vcn)
+			return -EINVAL;
+
+		next_vcn = vcn + len;
+
+		if (lcn == SPARSE_LCN)
+			continue;
+
+		if (sbi->flags & NTFS_FLAGS_NEED_REPLAY)
+			continue;
+
+		down_read_nested(&wnd->rw_lock, BITMAP_MUTEX_CLUSTERS);
+		/* Check for free blocks */
+		ok = wnd_is_used(wnd, lcn, len);
+		up_read(&wnd->rw_lock);
+		if (ok)
+			continue;
+
+		/* Looks like volume is corrupted */
+		ntfs_set_state(sbi, NTFS_DIRTY_ERROR);
+
+		if (down_write_trylock(&wnd->rw_lock)) {
+			/* mark all zero bits as used in range [lcn, lcn+len) */
+			CLST i, lcn_f = 0, len_f = 0;
+
+			err = 0;
+			for (i = 0; i < len; i++) {
+				if (wnd_is_free(wnd, lcn + i, 1)) {
+					if (!len_f)
+						lcn_f = lcn + i;
+					len_f += 1;
+				} else if (len_f) {
+					err = wnd_set_used(wnd, lcn_f, len_f);
+					len_f = 0;
+					if (err)
+						break;
+				}
+			}
+
+			if (len_f)
+				err = wnd_set_used(wnd, lcn_f, len_f);
+
+			up_write(&wnd->rw_lock);
+			if (err)
+				return err;
+		}
+	}
+
+	return ret;
+}
+#endif
+
+/*
+ * run_get_highest_vcn
+ *
+ * returns the highest vcn from a mapping pairs array
+ * it used while replaying log file
+ */
+int run_get_highest_vcn(CLST vcn, const u8 *run_buf, u64 *highest_vcn)
+{
+	u64 vcn64 = vcn;
+	u8 size_size;
+
+	while ((size_size = *run_buf & 0xF)) {
+		u8 offset_size = *run_buf++ >> 4;
+		u64 len;
+
+		if (size_size > 8 || offset_size > 8)
+			return -EINVAL;
+
+		len = run_unpack_s64(run_buf, size_size, 0);
+		if (!len)
+			return -EINVAL;
+
+		run_buf += size_size + offset_size;
+		vcn64 += len;
+
+#ifndef CONFIG_NTFS3_64BIT_CLUSTER
+		if (vcn64 > 0x100000000ull)
+			return -EINVAL;
+#endif
+	}
+
+	*highest_vcn = vcn64 - 1;
+	return 0;
+}