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Message-ID: <20201211161844.3590331-4-almaz.alexandrovich@paragon-software.com>
Date: Fri, 11 Dec 2020 19:18:37 +0300
From: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
To: <linux-fsdevel@...r.kernel.org>
CC: <viro@...iv.linux.org.uk>, <linux-kernel@...r.kernel.org>,
<pali@...nel.org>, <dsterba@...e.cz>, <aaptel@...e.com>,
<willy@...radead.org>, <rdunlap@...radead.org>, <joe@...ches.com>,
<mark@...mstone.com>, <nborisov@...e.com>,
<linux-ntfs-dev@...ts.sourceforge.net>, <anton@...era.com>,
<dan.carpenter@...cle.com>, <hch@....de>, <ebiggers@...nel.org>,
Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
Subject: [PATCH v15 03/10] fs/ntfs3: Add bitmap
This adds bitmap
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
---
fs/ntfs3/bitfunc.c | 135 ++++
fs/ntfs3/bitmap.c | 1504 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 1639 insertions(+)
create mode 100644 fs/ntfs3/bitfunc.c
create mode 100644 fs/ntfs3/bitmap.c
diff --git a/fs/ntfs3/bitfunc.c b/fs/ntfs3/bitfunc.c
new file mode 100644
index 000000000000..2d43d718d645
--- /dev/null
+++ b/fs/ntfs3/bitfunc.c
@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Copyright (C) 2019-2020 Paragon Software GmbH, All rights reserved.
+ *
+ */
+#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"
+
+#define BITS_IN_SIZE_T (sizeof(size_t) * 8)
+
+/*
+ * fill_mask[i] - first i bits are '1' , i = 0,1,2,3,4,5,6,7,8
+ * fill_mask[i] = 0xFF >> (8-i)
+ */
+static const u8 fill_mask[] = { 0x00, 0x01, 0x03, 0x07, 0x0F,
+ 0x1F, 0x3F, 0x7F, 0xFF };
+
+/*
+ * zero_mask[i] - first i bits are '0' , i = 0,1,2,3,4,5,6,7,8
+ * zero_mask[i] = 0xFF << i
+ */
+static const u8 zero_mask[] = { 0xFF, 0xFE, 0xFC, 0xF8, 0xF0,
+ 0xE0, 0xC0, 0x80, 0x00 };
+
+/*
+ * are_bits_clear
+ *
+ * Returns true if all bits [bit, bit+nbits) are zeros "0"
+ */
+bool are_bits_clear(const ulong *lmap, size_t bit, size_t nbits)
+{
+ size_t pos = bit & 7;
+ const u8 *map = (u8 *)lmap + (bit >> 3);
+
+ if (pos) {
+ if (8 - pos >= nbits)
+ return !nbits || !(*map & fill_mask[pos + nbits] &
+ zero_mask[pos]);
+
+ if (*map++ & zero_mask[pos])
+ return false;
+ nbits -= 8 - pos;
+ }
+
+ pos = ((size_t)map) & (sizeof(size_t) - 1);
+ if (pos) {
+ pos = sizeof(size_t) - pos;
+ if (nbits >= pos * 8) {
+ for (nbits -= pos * 8; pos; pos--, map++) {
+ if (*map)
+ return false;
+ }
+ }
+ }
+
+ for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
+ if (*((size_t *)map))
+ return false;
+ }
+
+ for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
+ if (*map)
+ return false;
+ }
+
+ pos = nbits & 7;
+ if (pos && (*map & fill_mask[pos]))
+ return false;
+
+ // All bits are zero
+ return true;
+}
+
+/*
+ * are_bits_set
+ *
+ * Returns true if all bits [bit, bit+nbits) are ones "1"
+ */
+bool are_bits_set(const ulong *lmap, size_t bit, size_t nbits)
+{
+ u8 mask;
+ size_t pos = bit & 7;
+ const u8 *map = (u8 *)lmap + (bit >> 3);
+
+ if (pos) {
+ if (8 - pos >= nbits) {
+ mask = fill_mask[pos + nbits] & zero_mask[pos];
+ return !nbits || (*map & mask) == mask;
+ }
+
+ mask = zero_mask[pos];
+ if ((*map++ & mask) != mask)
+ return false;
+ nbits -= 8 - pos;
+ }
+
+ pos = ((size_t)map) & (sizeof(size_t) - 1);
+ if (pos) {
+ pos = sizeof(size_t) - pos;
+ if (nbits >= pos * 8) {
+ for (nbits -= pos * 8; pos; pos--, map++) {
+ if (*map != 0xFF)
+ return false;
+ }
+ }
+ }
+
+ for (pos = nbits / BITS_IN_SIZE_T; pos; pos--, map += sizeof(size_t)) {
+ if (*((size_t *)map) != MINUS_ONE_T)
+ return false;
+ }
+
+ for (pos = (nbits % BITS_IN_SIZE_T) >> 3; pos; pos--, map++) {
+ if (*map != 0xFF)
+ return false;
+ }
+
+ pos = nbits & 7;
+ if (pos) {
+ u8 mask = fill_mask[pos];
+
+ if ((*map & mask) != mask)
+ return false;
+ }
+
+ // All bits are ones
+ return true;
+}
diff --git a/fs/ntfs3/bitmap.c b/fs/ntfs3/bitmap.c
new file mode 100644
index 000000000000..db7c4567c59a
--- /dev/null
+++ b/fs/ntfs3/bitmap.c
@@ -0,0 +1,1504 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Copyright (C) 2019-2020 Paragon Software GmbH, All rights reserved.
+ *
+ */
+
+#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"
+
+struct rb_node_key {
+ struct rb_node node;
+ size_t key;
+};
+
+/*
+ * Tree is sorted by start (key)
+ */
+struct e_node {
+ struct rb_node_key start; /* Tree sorted by start */
+ struct rb_node_key count; /* Tree sorted by len*/
+};
+
+static int wnd_rescan(struct wnd_bitmap *wnd);
+static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw);
+static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits);
+
+static inline u32 wnd_bits(const struct wnd_bitmap *wnd, size_t i)
+{
+ return i + 1 == wnd->nwnd ? wnd->bits_last : wnd->sb->s_blocksize * 8;
+}
+
+/*
+ * b_pos + b_len - biggest fragment
+ * Scan range [wpos wbits) window 'buf'
+ * Returns -1 if not found
+ */
+static size_t wnd_scan(const ulong *buf, size_t wbit, u32 wpos, u32 wend,
+ size_t to_alloc, size_t *prev_tail, size_t *b_pos,
+ size_t *b_len)
+{
+ while (wpos < wend) {
+ size_t free_len;
+ u32 free_bits, end;
+ u32 used = find_next_zero_bit(buf, wend, wpos);
+
+ if (used >= wend) {
+ if (*b_len < *prev_tail) {
+ *b_pos = wbit - *prev_tail;
+ *b_len = *prev_tail;
+ }
+
+ *prev_tail = 0;
+ return -1;
+ }
+
+ if (used > wpos) {
+ wpos = used;
+ if (*b_len < *prev_tail) {
+ *b_pos = wbit - *prev_tail;
+ *b_len = *prev_tail;
+ }
+
+ *prev_tail = 0;
+ }
+
+ /*
+ * Now we have a fragment [wpos, wend) staring with 0
+ */
+ end = wpos + to_alloc - *prev_tail;
+ free_bits = find_next_bit(buf, min(end, wend), wpos);
+
+ free_len = *prev_tail + free_bits - wpos;
+
+ if (*b_len < free_len) {
+ *b_pos = wbit + wpos - *prev_tail;
+ *b_len = free_len;
+ }
+
+ if (free_len >= to_alloc)
+ return wbit + wpos - *prev_tail;
+
+ if (free_bits >= wend) {
+ *prev_tail += free_bits - wpos;
+ return -1;
+ }
+
+ wpos = free_bits + 1;
+
+ *prev_tail = 0;
+ }
+
+ return -1;
+}
+
+/*
+ * wnd_close
+ *
+ *
+ */
+void wnd_close(struct wnd_bitmap *wnd)
+{
+ struct rb_node *node, *next;
+
+ if (wnd->free_bits != wnd->free_holder)
+ ntfs_free(wnd->free_bits);
+ run_close(&wnd->run);
+
+ node = rb_first(&wnd->start_tree);
+
+ while (node) {
+ next = rb_next(node);
+ rb_erase(node, &wnd->start_tree);
+ ntfs_free(rb_entry(node, struct e_node, start.node));
+ node = next;
+ }
+}
+
+static struct rb_node *rb_lookup(struct rb_root *root, size_t v)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *r = NULL;
+
+ while (*p) {
+ struct rb_node_key *k;
+
+ k = rb_entry(*p, struct rb_node_key, node);
+ if (v < k->key) {
+ p = &(*p)->rb_left;
+ } else if (v > k->key) {
+ r = &k->node;
+ p = &(*p)->rb_right;
+ } else {
+ return &k->node;
+ }
+ }
+
+ return r;
+}
+
+/*
+ * rb_insert_count
+ *
+ * Helper function to insert special kind of 'count' tree
+ */
+static inline bool rb_insert_count(struct rb_root *root, struct e_node *e)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ size_t e_ckey = e->count.key;
+ size_t e_skey = e->start.key;
+
+ while (*p) {
+ struct e_node *k =
+ rb_entry(parent = *p, struct e_node, count.node);
+
+ if (e_ckey > k->count.key) {
+ p = &(*p)->rb_left;
+ } else if (e_ckey < k->count.key) {
+ p = &(*p)->rb_right;
+ } else if (e_skey < k->start.key) {
+ p = &(*p)->rb_left;
+ } else if (e_skey > k->start.key) {
+ p = &(*p)->rb_right;
+ } else {
+ WARN_ON(1);
+ return false;
+ }
+ }
+
+ rb_link_node(&e->count.node, parent, p);
+ rb_insert_color(&e->count.node, root);
+ return true;
+}
+
+/*
+ * inline bool rb_insert_start
+ *
+ * Helper function to insert special kind of 'count' tree
+ */
+static inline bool rb_insert_start(struct rb_root *root, struct e_node *e)
+{
+ struct rb_node **p = &root->rb_node;
+ struct rb_node *parent = NULL;
+ size_t e_skey = e->start.key;
+
+ while (*p) {
+ struct e_node *k;
+
+ parent = *p;
+
+ k = rb_entry(parent, struct e_node, start.node);
+ if (e_skey < k->start.key) {
+ p = &(*p)->rb_left;
+ } else if (e_skey > k->start.key) {
+ p = &(*p)->rb_right;
+ } else {
+ WARN_ON(1);
+ return false;
+ }
+ }
+
+ rb_link_node(&e->start.node, parent, p);
+ rb_insert_color(&e->start.node, root);
+ return true;
+}
+
+#define NTFS_MAX_WND_EXTENTS (32u * 1024u)
+
+/*
+ * wnd_add_free_ext
+ *
+ * adds a new extent of free space
+ * build = 1 when building tree
+ */
+static void wnd_add_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len,
+ bool build)
+{
+ struct e_node *e, *e0 = NULL;
+ size_t ib, end_in = bit + len;
+ struct rb_node *n;
+
+ if (build) {
+ /* Use extent_min to filter too short extents */
+ if (wnd->count >= NTFS_MAX_WND_EXTENTS &&
+ len <= wnd->extent_min) {
+ wnd->uptodated = -1;
+ return;
+ }
+ } else {
+ /* Try to find extent before 'bit' */
+ n = rb_lookup(&wnd->start_tree, bit);
+
+ if (!n) {
+ n = rb_first(&wnd->start_tree);
+ } else {
+ e = rb_entry(n, struct e_node, start.node);
+ n = rb_next(n);
+ if (e->start.key + e->count.key == bit) {
+ /* Remove left */
+ bit = e->start.key;
+ len += e->count.key;
+ rb_erase(&e->start.node, &wnd->start_tree);
+ rb_erase(&e->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+ e0 = e;
+ }
+ }
+
+ while (n) {
+ size_t next_end;
+
+ e = rb_entry(n, struct e_node, start.node);
+ next_end = e->start.key + e->count.key;
+ if (e->start.key > end_in)
+ break;
+
+ /* Remove right */
+ n = rb_next(n);
+ len += next_end - end_in;
+ end_in = next_end;
+ rb_erase(&e->start.node, &wnd->start_tree);
+ rb_erase(&e->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+
+ if (!e0)
+ e0 = e;
+ else
+ ntfs_free(e);
+ }
+
+ if (wnd->uptodated != 1) {
+ /* Check bits before 'bit' */
+ ib = wnd->zone_bit == wnd->zone_end ||
+ bit < wnd->zone_end ?
+ 0 :
+ wnd->zone_end;
+
+ while (bit > ib && wnd_is_free_hlp(wnd, bit - 1, 1)) {
+ bit -= 1;
+ len += 1;
+ }
+
+ /* Check bits after 'end_in' */
+ ib = wnd->zone_bit == wnd->zone_end ||
+ end_in > wnd->zone_bit ?
+ wnd->nbits :
+ wnd->zone_bit;
+
+ while (end_in < ib && wnd_is_free_hlp(wnd, end_in, 1)) {
+ end_in += 1;
+ len += 1;
+ }
+ }
+ }
+ /* Insert new fragment */
+ if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
+ if (e0)
+ ntfs_free(e0);
+
+ wnd->uptodated = -1;
+
+ /* Compare with smallest fragment */
+ n = rb_last(&wnd->count_tree);
+ e = rb_entry(n, struct e_node, count.node);
+ if (len <= e->count.key)
+ goto out; /* Do not insert small fragments */
+
+ if (build) {
+ struct e_node *e2;
+
+ n = rb_prev(n);
+ e2 = rb_entry(n, struct e_node, count.node);
+ /* smallest fragment will be 'e2->count.key' */
+ wnd->extent_min = e2->count.key;
+ }
+
+ /* Replace smallest fragment by new one */
+ rb_erase(&e->start.node, &wnd->start_tree);
+ rb_erase(&e->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+ } else {
+ e = e0 ? e0 : ntfs_alloc(sizeof(struct e_node), 0);
+ if (!e) {
+ wnd->uptodated = -1;
+ goto out;
+ }
+
+ if (build && len <= wnd->extent_min)
+ wnd->extent_min = len;
+ }
+ e->start.key = bit;
+ e->count.key = len;
+ if (len > wnd->extent_max)
+ wnd->extent_max = len;
+
+ rb_insert_start(&wnd->start_tree, e);
+ rb_insert_count(&wnd->count_tree, e);
+ wnd->count += 1;
+
+out:;
+}
+
+/*
+ * wnd_remove_free_ext
+ *
+ * removes a run from the cached free space
+ */
+static void wnd_remove_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len)
+{
+ struct rb_node *n, *n3;
+ struct e_node *e, *e3;
+ size_t end_in = bit + len;
+ size_t end3, end, new_key, new_len, max_new_len;
+
+ /* Try to find extent before 'bit' */
+ n = rb_lookup(&wnd->start_tree, bit);
+
+ if (!n)
+ return;
+
+ e = rb_entry(n, struct e_node, start.node);
+ end = e->start.key + e->count.key;
+
+ new_key = new_len = 0;
+ len = e->count.key;
+
+ /* Range [bit,end_in) must be inside 'e' or outside 'e' and 'n' */
+ if (e->start.key > bit)
+ ;
+ else if (end_in <= end) {
+ /* Range [bit,end_in) inside 'e' */
+ new_key = end_in;
+ new_len = end - end_in;
+ len = bit - e->start.key;
+ } else if (bit > end) {
+ bool bmax = false;
+
+ n3 = rb_next(n);
+
+ while (n3) {
+ e3 = rb_entry(n3, struct e_node, start.node);
+ if (e3->start.key >= end_in)
+ break;
+
+ if (e3->count.key == wnd->extent_max)
+ bmax = true;
+
+ end3 = e3->start.key + e3->count.key;
+ if (end3 > end_in) {
+ e3->start.key = end_in;
+ rb_erase(&e3->count.node, &wnd->count_tree);
+ e3->count.key = end3 - end_in;
+ rb_insert_count(&wnd->count_tree, e3);
+ break;
+ }
+
+ n3 = rb_next(n3);
+ rb_erase(&e3->start.node, &wnd->start_tree);
+ rb_erase(&e3->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+ ntfs_free(e3);
+ }
+ if (!bmax)
+ return;
+ n3 = rb_first(&wnd->count_tree);
+ wnd->extent_max =
+ n3 ? rb_entry(n3, struct e_node, count.node)->count.key :
+ 0;
+ return;
+ }
+
+ if (e->count.key != wnd->extent_max) {
+ ;
+ } else if (rb_prev(&e->count.node)) {
+ ;
+ } else {
+ n3 = rb_next(&e->count.node);
+ max_new_len = len > new_len ? len : new_len;
+ if (!n3) {
+ wnd->extent_max = max_new_len;
+ } else {
+ e3 = rb_entry(n3, struct e_node, count.node);
+ wnd->extent_max = max(e3->count.key, max_new_len);
+ }
+ }
+
+ if (!len) {
+ if (new_len) {
+ e->start.key = new_key;
+ rb_erase(&e->count.node, &wnd->count_tree);
+ e->count.key = new_len;
+ rb_insert_count(&wnd->count_tree, e);
+ } else {
+ rb_erase(&e->start.node, &wnd->start_tree);
+ rb_erase(&e->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+ ntfs_free(e);
+ }
+ goto out;
+ }
+ rb_erase(&e->count.node, &wnd->count_tree);
+ e->count.key = len;
+ rb_insert_count(&wnd->count_tree, e);
+
+ if (!new_len)
+ goto out;
+
+ if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
+ wnd->uptodated = -1;
+
+ /* Get minimal extent */
+ e = rb_entry(rb_last(&wnd->count_tree), struct e_node,
+ count.node);
+ if (e->count.key > new_len)
+ goto out;
+
+ /* Replace minimum */
+ rb_erase(&e->start.node, &wnd->start_tree);
+ rb_erase(&e->count.node, &wnd->count_tree);
+ wnd->count -= 1;
+ } else {
+ e = ntfs_alloc(sizeof(struct e_node), 0);
+ if (!e)
+ wnd->uptodated = -1;
+ }
+
+ if (e) {
+ e->start.key = new_key;
+ e->count.key = new_len;
+ rb_insert_start(&wnd->start_tree, e);
+ rb_insert_count(&wnd->count_tree, e);
+ wnd->count += 1;
+ }
+
+out:
+ if (!wnd->count && 1 != wnd->uptodated)
+ wnd_rescan(wnd);
+}
+
+/*
+ * wnd_rescan
+ *
+ * Scan all bitmap. used while initialization.
+ */
+static int wnd_rescan(struct wnd_bitmap *wnd)
+{
+ int err = 0;
+ size_t prev_tail = 0;
+ struct super_block *sb = wnd->sb;
+ struct ntfs_sb_info *sbi = sb->s_fs_info;
+ u64 lbo, len = 0;
+ u32 blocksize = sb->s_blocksize;
+ u8 cluster_bits = sbi->cluster_bits;
+ u32 wbits = 8 * sb->s_blocksize;
+ u32 used, frb;
+ const ulong *buf;
+ size_t wpos, wbit, iw, vbo;
+ struct buffer_head *bh = NULL;
+ CLST lcn, clen;
+
+ wnd->uptodated = 0;
+ wnd->extent_max = 0;
+ wnd->extent_min = MINUS_ONE_T;
+ wnd->total_zeroes = 0;
+
+ vbo = 0;
+
+ for (iw = 0; iw < wnd->nwnd; iw++) {
+ if (iw + 1 == wnd->nwnd)
+ wbits = wnd->bits_last;
+
+ if (wnd->inited) {
+ if (!wnd->free_bits[iw]) {
+ /* all ones */
+ if (prev_tail) {
+ wnd_add_free_ext(wnd,
+ vbo * 8 - prev_tail,
+ prev_tail, true);
+ prev_tail = 0;
+ }
+ goto next_wnd;
+ }
+ if (wbits == wnd->free_bits[iw]) {
+ /* all zeroes */
+ prev_tail += wbits;
+ wnd->total_zeroes += wbits;
+ goto next_wnd;
+ }
+ }
+
+ if (!len) {
+ if (!run_lookup_entry(&wnd->run, vbo >> cluster_bits,
+ &lcn, &clen, NULL)) {
+ err = -ENOENT;
+ goto out;
+ }
+
+ lbo = (u64)lcn << cluster_bits;
+ len = (u64)clen << cluster_bits;
+ }
+
+ bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);
+ if (!bh) {
+ err = -EIO;
+ goto out;
+ }
+
+ buf = (ulong *)bh->b_data;
+
+ used = __bitmap_weight(buf, wbits);
+ if (used < wbits) {
+ frb = wbits - used;
+ wnd->free_bits[iw] = frb;
+ wnd->total_zeroes += frb;
+ }
+
+ wpos = 0;
+ wbit = vbo * 8;
+
+ if (wbit + wbits > wnd->nbits)
+ wbits = wnd->nbits - wbit;
+
+ do {
+ used = find_next_zero_bit(buf, wbits, wpos);
+
+ if (used > wpos && prev_tail) {
+ wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
+ prev_tail, true);
+ prev_tail = 0;
+ }
+
+ wpos = used;
+
+ if (wpos >= wbits) {
+ /* No free blocks */
+ prev_tail = 0;
+ break;
+ }
+
+ frb = find_next_bit(buf, wbits, wpos);
+ if (frb >= wbits) {
+ /* keep last free block */
+ prev_tail += frb - wpos;
+ break;
+ }
+
+ wnd_add_free_ext(wnd, wbit + wpos - prev_tail,
+ frb + prev_tail - wpos, true);
+
+ /* Skip free block and first '1' */
+ wpos = frb + 1;
+ /* Reset previous tail */
+ prev_tail = 0;
+ } while (wpos < wbits);
+
+next_wnd:
+
+ if (bh)
+ put_bh(bh);
+ bh = NULL;
+
+ vbo += blocksize;
+ if (len) {
+ len -= blocksize;
+ lbo += blocksize;
+ }
+ }
+
+ /* Add last block */
+ if (prev_tail)
+ wnd_add_free_ext(wnd, wnd->nbits - prev_tail, prev_tail, true);
+
+ /*
+ * Before init cycle wnd->uptodated was 0
+ * If any errors or limits occurs while initialization then
+ * wnd->uptodated will be -1
+ * If 'uptodated' is still 0 then Tree is really updated
+ */
+ if (!wnd->uptodated)
+ wnd->uptodated = 1;
+
+ if (wnd->zone_bit != wnd->zone_end) {
+ size_t zlen = wnd->zone_end - wnd->zone_bit;
+
+ wnd->zone_end = wnd->zone_bit;
+ wnd_zone_set(wnd, wnd->zone_bit, zlen);
+ }
+
+out:
+ return err;
+}
+
+/*
+ * wnd_init
+ */
+int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits)
+{
+ int err;
+ u32 blocksize = sb->s_blocksize;
+ u32 wbits = blocksize * 8;
+
+ init_rwsem(&wnd->rw_lock);
+
+ wnd->sb = sb;
+ wnd->nbits = nbits;
+ wnd->total_zeroes = nbits;
+ wnd->extent_max = MINUS_ONE_T;
+ wnd->zone_bit = wnd->zone_end = 0;
+ wnd->nwnd = bytes_to_block(sb, bitmap_size(nbits));
+ wnd->bits_last = nbits & (wbits - 1);
+ if (!wnd->bits_last)
+ wnd->bits_last = wbits;
+
+ if (wnd->nwnd <= ARRAY_SIZE(wnd->free_holder)) {
+ wnd->free_bits = wnd->free_holder;
+ } else {
+ wnd->free_bits = ntfs_alloc(wnd->nwnd * sizeof(u16), 1);
+ if (!wnd->free_bits)
+ return -ENOMEM;
+ }
+
+ err = wnd_rescan(wnd);
+ if (err)
+ return err;
+
+ wnd->inited = true;
+
+ return 0;
+}
+
+/*
+ * wnd_map
+ *
+ * call sb_bread for requested window
+ */
+static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw)
+{
+ size_t vbo;
+ CLST lcn, clen;
+ struct super_block *sb = wnd->sb;
+ struct ntfs_sb_info *sbi;
+ struct buffer_head *bh;
+ u64 lbo;
+
+ sbi = sb->s_fs_info;
+ vbo = (u64)iw << sb->s_blocksize_bits;
+
+ if (!run_lookup_entry(&wnd->run, vbo >> sbi->cluster_bits, &lcn, &clen,
+ NULL)) {
+ return ERR_PTR(-ENOENT);
+ }
+
+ lbo = ((u64)lcn << sbi->cluster_bits) + (vbo & sbi->cluster_mask);
+
+ bh = ntfs_bread(wnd->sb, lbo >> sb->s_blocksize_bits);
+ if (!bh)
+ return ERR_PTR(-EIO);
+
+ return bh;
+}
+
+/*
+ * wnd_set_free
+ *
+ * Marks the bits range from bit to bit + bits as free
+ */
+int wnd_set_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
+{
+ int err = 0;
+ struct super_block *sb = wnd->sb;
+ size_t bits0 = bits;
+ u32 wbits = 8 * sb->s_blocksize;
+ size_t iw = bit >> (sb->s_blocksize_bits + 3);
+ u32 wbit = bit & (wbits - 1);
+ struct buffer_head *bh;
+
+ while (iw < wnd->nwnd && bits) {
+ u32 tail, op;
+ ulong *buf;
+
+ if (iw + 1 == wnd->nwnd)
+ wbits = wnd->bits_last;
+
+ tail = wbits - wbit;
+ op = tail < bits ? tail : bits;
+
+ bh = wnd_map(wnd, iw);
+ if (IS_ERR(bh)) {
+ err = PTR_ERR(bh);
+ break;
+ }
+
+ buf = (ulong *)bh->b_data;
+
+ lock_buffer(bh);
+
+ __bitmap_clear(buf, wbit, op);
+
+ wnd->free_bits[iw] += op;
+
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ put_bh(bh);
+
+ wnd->total_zeroes += op;
+ bits -= op;
+ wbit = 0;
+ iw += 1;
+ }
+
+ wnd_add_free_ext(wnd, bit, bits0, false);
+
+ return err;
+}
+
+/*
+ * wnd_set_used
+ *
+ * Marks the bits range from bit to bit + bits as used
+ */
+int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
+{
+ int err = 0;
+ struct super_block *sb = wnd->sb;
+ size_t bits0 = bits;
+ size_t iw = bit >> (sb->s_blocksize_bits + 3);
+ u32 wbits = 8 * sb->s_blocksize;
+ u32 wbit = bit & (wbits - 1);
+ struct buffer_head *bh;
+
+ while (iw < wnd->nwnd && bits) {
+ u32 tail, op;
+ ulong *buf;
+
+ if (unlikely(iw + 1 == wnd->nwnd))
+ wbits = wnd->bits_last;
+
+ tail = wbits - wbit;
+ op = tail < bits ? tail : bits;
+
+ bh = wnd_map(wnd, iw);
+ if (IS_ERR(bh)) {
+ err = PTR_ERR(bh);
+ break;
+ }
+ buf = (ulong *)bh->b_data;
+
+ lock_buffer(bh);
+
+ __bitmap_set(buf, wbit, op);
+ wnd->free_bits[iw] -= op;
+
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ put_bh(bh);
+
+ wnd->total_zeroes -= op;
+ bits -= op;
+ wbit = 0;
+ iw += 1;
+ }
+
+ if (!RB_EMPTY_ROOT(&wnd->start_tree))
+ wnd_remove_free_ext(wnd, bit, bits0);
+
+ return err;
+}
+
+/*
+ * wnd_is_free_hlp
+ *
+ * Returns true if all clusters [bit, bit+bits) are free (bitmap only)
+ */
+static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits)
+{
+ struct super_block *sb = wnd->sb;
+ size_t iw = bit >> (sb->s_blocksize_bits + 3);
+ u32 wbits = 8 * sb->s_blocksize;
+ u32 wbit = bit & (wbits - 1);
+
+ while (iw < wnd->nwnd && bits) {
+ u32 tail, op;
+
+ if (unlikely(iw + 1 == wnd->nwnd))
+ wbits = wnd->bits_last;
+
+ tail = wbits - wbit;
+ op = tail < bits ? tail : bits;
+
+ if (wbits != wnd->free_bits[iw]) {
+ bool ret;
+ struct buffer_head *bh = wnd_map(wnd, iw);
+
+ if (IS_ERR(bh))
+ return false;
+
+ ret = are_bits_clear((ulong *)bh->b_data, wbit, op);
+
+ put_bh(bh);
+ if (!ret)
+ return false;
+ }
+
+ bits -= op;
+ wbit = 0;
+ iw += 1;
+ }
+
+ return true;
+}
+
+/*
+ * wnd_is_free
+ *
+ * Returns true if all clusters [bit, bit+bits) are free
+ */
+bool wnd_is_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
+{
+ bool ret;
+ struct rb_node *n;
+ size_t end;
+ struct e_node *e;
+
+ if (RB_EMPTY_ROOT(&wnd->start_tree))
+ goto use_wnd;
+
+ n = rb_lookup(&wnd->start_tree, bit);
+ if (!n)
+ goto use_wnd;
+
+ e = rb_entry(n, struct e_node, start.node);
+
+ end = e->start.key + e->count.key;
+
+ if (bit < end && bit + bits <= end)
+ return true;
+
+use_wnd:
+ ret = wnd_is_free_hlp(wnd, bit, bits);
+
+ return ret;
+}
+
+/*
+ * wnd_is_used
+ *
+ * Returns true if all clusters [bit, bit+bits) are used
+ */
+bool wnd_is_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
+{
+ bool ret = false;
+ struct super_block *sb = wnd->sb;
+ size_t iw = bit >> (sb->s_blocksize_bits + 3);
+ u32 wbits = 8 * sb->s_blocksize;
+ u32 wbit = bit & (wbits - 1);
+ size_t end;
+ struct rb_node *n;
+ struct e_node *e;
+
+ if (RB_EMPTY_ROOT(&wnd->start_tree))
+ goto use_wnd;
+
+ end = bit + bits;
+ n = rb_lookup(&wnd->start_tree, end - 1);
+ if (!n)
+ goto use_wnd;
+
+ e = rb_entry(n, struct e_node, start.node);
+ if (e->start.key + e->count.key > bit)
+ return false;
+
+use_wnd:
+ while (iw < wnd->nwnd && bits) {
+ u32 tail, op;
+
+ if (unlikely(iw + 1 == wnd->nwnd))
+ wbits = wnd->bits_last;
+
+ tail = wbits - wbit;
+ op = tail < bits ? tail : bits;
+
+ if (wnd->free_bits[iw]) {
+ bool ret;
+ struct buffer_head *bh = wnd_map(wnd, iw);
+
+ if (IS_ERR(bh))
+ goto out;
+
+ ret = are_bits_set((ulong *)bh->b_data, wbit, op);
+ put_bh(bh);
+ if (!ret)
+ goto out;
+ }
+
+ bits -= op;
+ wbit = 0;
+ iw += 1;
+ }
+ ret = true;
+
+out:
+ return ret;
+}
+
+/*
+ * wnd_find
+ * - flags - BITMAP_FIND_XXX flags
+ *
+ * looks for free space
+ * Returns 0 if not found
+ */
+size_t wnd_find(struct wnd_bitmap *wnd, size_t to_alloc, size_t hint,
+ size_t flags, size_t *allocated)
+{
+ struct super_block *sb;
+ u32 wbits, wpos, wzbit, wzend;
+ size_t fnd, max_alloc, b_len, b_pos;
+ size_t iw, prev_tail, nwnd, wbit, ebit, zbit, zend;
+ size_t to_alloc0 = to_alloc;
+ const ulong *buf;
+ const struct e_node *e;
+ const struct rb_node *pr, *cr;
+ u8 log2_bits;
+ bool fbits_valid;
+ struct buffer_head *bh;
+
+ /* fast checking for available free space */
+ if (flags & BITMAP_FIND_FULL) {
+ size_t zeroes = wnd_zeroes(wnd);
+
+ zeroes -= wnd->zone_end - wnd->zone_bit;
+ if (zeroes < to_alloc0)
+ goto no_space;
+
+ if (to_alloc0 > wnd->extent_max)
+ goto no_space;
+ } else {
+ if (to_alloc > wnd->extent_max)
+ to_alloc = wnd->extent_max;
+ }
+
+ if (wnd->zone_bit <= hint && hint < wnd->zone_end)
+ hint = wnd->zone_end;
+
+ max_alloc = wnd->nbits;
+ b_len = b_pos = 0;
+
+ if (hint >= max_alloc)
+ hint = 0;
+
+ if (RB_EMPTY_ROOT(&wnd->start_tree)) {
+ if (wnd->uptodated == 1) {
+ /* extents tree is updated -> no free space */
+ goto no_space;
+ }
+ goto scan_bitmap;
+ }
+
+ e = NULL;
+ if (!hint)
+ goto allocate_biggest;
+
+ /* Use hint: enumerate extents by start >= hint */
+ pr = NULL;
+ cr = wnd->start_tree.rb_node;
+
+ for (;;) {
+ e = rb_entry(cr, struct e_node, start.node);
+
+ if (e->start.key == hint)
+ break;
+
+ if (e->start.key < hint) {
+ pr = cr;
+ cr = cr->rb_right;
+ if (!cr)
+ break;
+ continue;
+ }
+
+ cr = cr->rb_left;
+ if (!cr) {
+ e = pr ? rb_entry(pr, struct e_node, start.node) : NULL;
+ break;
+ }
+ }
+
+ if (!e)
+ goto allocate_biggest;
+
+ if (e->start.key + e->count.key > hint) {
+ /* We have found extension with 'hint' inside */
+ size_t len = e->start.key + e->count.key - hint;
+
+ if (len >= to_alloc && hint + to_alloc <= max_alloc) {
+ fnd = hint;
+ goto found;
+ }
+
+ if (!(flags & BITMAP_FIND_FULL)) {
+ if (len > to_alloc)
+ len = to_alloc;
+
+ if (hint + len <= max_alloc) {
+ fnd = hint;
+ to_alloc = len;
+ goto found;
+ }
+ }
+ }
+
+allocate_biggest:
+ /* Allocate from biggest free extent */
+ e = rb_entry(rb_first(&wnd->count_tree), struct e_node, count.node);
+ if (e->count.key != wnd->extent_max)
+ wnd->extent_max = e->count.key;
+
+ if (e->count.key < max_alloc) {
+ if (e->count.key >= to_alloc) {
+ ;
+ } else if (flags & BITMAP_FIND_FULL) {
+ if (e->count.key < to_alloc0) {
+ /* Biggest free block is less then requested */
+ goto no_space;
+ }
+ to_alloc = e->count.key;
+ } else if (-1 != wnd->uptodated) {
+ to_alloc = e->count.key;
+ } else {
+ /* Check if we can use more bits */
+ size_t op, max_check;
+ struct rb_root start_tree;
+
+ memcpy(&start_tree, &wnd->start_tree,
+ sizeof(struct rb_root));
+ memset(&wnd->start_tree, 0, sizeof(struct rb_root));
+
+ max_check = e->start.key + to_alloc;
+ if (max_check > max_alloc)
+ max_check = max_alloc;
+ for (op = e->start.key + e->count.key; op < max_check;
+ op++) {
+ if (!wnd_is_free(wnd, op, 1))
+ break;
+ }
+ memcpy(&wnd->start_tree, &start_tree,
+ sizeof(struct rb_root));
+ to_alloc = op - e->start.key;
+ }
+
+ /* Prepare to return */
+ fnd = e->start.key;
+ if (e->start.key + to_alloc > max_alloc)
+ to_alloc = max_alloc - e->start.key;
+ goto found;
+ }
+
+ if (wnd->uptodated == 1) {
+ /* extents tree is updated -> no free space */
+ goto no_space;
+ }
+
+ b_len = e->count.key;
+ b_pos = e->start.key;
+
+scan_bitmap:
+ sb = wnd->sb;
+ log2_bits = sb->s_blocksize_bits + 3;
+
+ /* At most two ranges [hint, max_alloc) + [0, hint) */
+Again:
+
+ /* TODO: optimize request for case nbits > wbits */
+ iw = hint >> log2_bits;
+ wbits = sb->s_blocksize * 8;
+ wpos = hint & (wbits - 1);
+ prev_tail = 0;
+ fbits_valid = true;
+
+ if (max_alloc == wnd->nbits) {
+ nwnd = wnd->nwnd;
+ } else {
+ size_t t = max_alloc + wbits - 1;
+
+ nwnd = likely(t > max_alloc) ? (t >> log2_bits) : wnd->nwnd;
+ }
+
+ /* Enumerate all windows */
+ for (; iw < nwnd; iw++) {
+ wbit = iw << log2_bits;
+
+ if (!wnd->free_bits[iw]) {
+ if (prev_tail > b_len) {
+ b_pos = wbit - prev_tail;
+ b_len = prev_tail;
+ }
+
+ /* Skip full used window */
+ prev_tail = 0;
+ wpos = 0;
+ continue;
+ }
+
+ if (unlikely(iw + 1 == nwnd)) {
+ if (max_alloc == wnd->nbits) {
+ wbits = wnd->bits_last;
+ } else {
+ size_t t = max_alloc & (wbits - 1);
+
+ if (t) {
+ wbits = t;
+ fbits_valid = false;
+ }
+ }
+ }
+
+ if (wnd->zone_end > wnd->zone_bit) {
+ ebit = wbit + wbits;
+ zbit = max(wnd->zone_bit, wbit);
+ zend = min(wnd->zone_end, ebit);
+
+ /* Here we have a window [wbit, ebit) and zone [zbit, zend) */
+ if (zend <= zbit) {
+ /* Zone does not overlap window */
+ } else {
+ wzbit = zbit - wbit;
+ wzend = zend - wbit;
+
+ /* Zone overlaps window */
+ if (wnd->free_bits[iw] == wzend - wzbit) {
+ prev_tail = 0;
+ wpos = 0;
+ continue;
+ }
+
+ /* Scan two ranges window: [wbit, zbit) and [zend, ebit) */
+ bh = wnd_map(wnd, iw);
+
+ if (IS_ERR(bh)) {
+ /* TODO: error */
+ prev_tail = 0;
+ wpos = 0;
+ continue;
+ }
+
+ buf = (ulong *)bh->b_data;
+
+ /* Scan range [wbit, zbit) */
+ if (wpos < wzbit) {
+ /* Scan range [wpos, zbit) */
+ fnd = wnd_scan(buf, wbit, wpos, wzbit,
+ to_alloc, &prev_tail,
+ &b_pos, &b_len);
+ if (fnd != MINUS_ONE_T) {
+ put_bh(bh);
+ goto found;
+ }
+ }
+
+ prev_tail = 0;
+
+ /* Scan range [zend, ebit) */
+ if (wzend < wbits) {
+ fnd = wnd_scan(buf, wbit,
+ max(wzend, wpos), wbits,
+ to_alloc, &prev_tail,
+ &b_pos, &b_len);
+ if (fnd != MINUS_ONE_T) {
+ put_bh(bh);
+ goto found;
+ }
+ }
+
+ wpos = 0;
+ put_bh(bh);
+ continue;
+ }
+ }
+
+ /* Current window does not overlap zone */
+ if (!wpos && fbits_valid && wnd->free_bits[iw] == wbits) {
+ /* window is empty */
+ if (prev_tail + wbits >= to_alloc) {
+ fnd = wbit + wpos - prev_tail;
+ goto found;
+ }
+
+ /* Increase 'prev_tail' and process next window */
+ prev_tail += wbits;
+ wpos = 0;
+ continue;
+ }
+
+ /* read window */
+ bh = wnd_map(wnd, iw);
+ if (IS_ERR(bh)) {
+ // TODO: error
+ prev_tail = 0;
+ wpos = 0;
+ continue;
+ }
+
+ buf = (ulong *)bh->b_data;
+
+ /* Scan range [wpos, eBits) */
+ fnd = wnd_scan(buf, wbit, wpos, wbits, to_alloc, &prev_tail,
+ &b_pos, &b_len);
+ put_bh(bh);
+ if (fnd != MINUS_ONE_T)
+ goto found;
+ }
+
+ if (b_len < prev_tail) {
+ /* The last fragment */
+ b_len = prev_tail;
+ b_pos = max_alloc - prev_tail;
+ }
+
+ if (hint) {
+ /*
+ * We have scanned range [hint max_alloc)
+ * Prepare to scan range [0 hint + to_alloc)
+ */
+ size_t nextmax = hint + to_alloc;
+
+ if (likely(nextmax >= hint) && nextmax < max_alloc)
+ max_alloc = nextmax;
+ hint = 0;
+ goto Again;
+ }
+
+ if (!b_len)
+ goto no_space;
+
+ wnd->extent_max = b_len;
+
+ if (flags & BITMAP_FIND_FULL)
+ goto no_space;
+
+ fnd = b_pos;
+ to_alloc = b_len;
+
+found:
+ if (flags & BITMAP_FIND_MARK_AS_USED) {
+ /* TODO optimize remove extent (pass 'e'?) */
+ if (wnd_set_used(wnd, fnd, to_alloc))
+ goto no_space;
+ } else if (wnd->extent_max != MINUS_ONE_T &&
+ to_alloc > wnd->extent_max) {
+ wnd->extent_max = to_alloc;
+ }
+
+ *allocated = fnd;
+ return to_alloc;
+
+no_space:
+ return 0;
+}
+
+/*
+ * wnd_extend
+ *
+ * Extend bitmap ($MFT bitmap)
+ */
+int wnd_extend(struct wnd_bitmap *wnd, size_t new_bits)
+{
+ int err;
+ struct super_block *sb = wnd->sb;
+ struct ntfs_sb_info *sbi = sb->s_fs_info;
+ u32 blocksize = sb->s_blocksize;
+ u32 wbits = blocksize * 8;
+ u32 b0, new_last;
+ size_t bits, iw, new_wnd;
+ size_t old_bits = wnd->nbits;
+ u16 *new_free;
+
+ if (new_bits <= old_bits)
+ return -EINVAL;
+
+ /* align to 8 byte boundary */
+ new_wnd = bytes_to_block(sb, bitmap_size(new_bits));
+ new_last = new_bits & (wbits - 1);
+ if (!new_last)
+ new_last = wbits;
+
+ if (new_wnd != wnd->nwnd) {
+ if (new_wnd <= ARRAY_SIZE(wnd->free_holder)) {
+ new_free = wnd->free_holder;
+ } else {
+ new_free = ntfs_alloc(new_wnd * sizeof(u16), 0);
+ if (!new_free)
+ return -ENOMEM;
+ }
+
+ if (new_free != wnd->free_bits)
+ memcpy(new_free, wnd->free_bits,
+ wnd->nwnd * sizeof(short));
+ memset(new_free + wnd->nwnd, 0,
+ (new_wnd - wnd->nwnd) * sizeof(short));
+ if (wnd->free_bits != wnd->free_holder)
+ ntfs_free(wnd->free_bits);
+
+ wnd->free_bits = new_free;
+ }
+
+ /* Zero bits [old_bits,new_bits) */
+ bits = new_bits - old_bits;
+ b0 = old_bits & (wbits - 1);
+
+ for (iw = old_bits >> (sb->s_blocksize_bits + 3); bits; iw += 1) {
+ u32 op;
+ size_t frb;
+ u64 vbo, lbo, bytes;
+ struct buffer_head *bh;
+ ulong *buf;
+
+ if (iw + 1 == new_wnd)
+ wbits = new_last;
+
+ op = b0 + bits > wbits ? wbits - b0 : bits;
+ vbo = (u64)iw * blocksize;
+
+ err = ntfs_vbo_to_lbo(sbi, &wnd->run, vbo, &lbo, &bytes);
+ if (err)
+ break;
+
+ bh = ntfs_bread(sb, lbo >> sb->s_blocksize_bits);
+ if (!bh)
+ return -EIO;
+
+ lock_buffer(bh);
+ buf = (ulong *)bh->b_data;
+
+ __bitmap_clear(buf, b0, blocksize * 8 - b0);
+ frb = wbits - __bitmap_weight(buf, wbits);
+ wnd->total_zeroes += frb - wnd->free_bits[iw];
+ wnd->free_bits[iw] = frb;
+
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ /*err = sync_dirty_buffer(bh);*/
+
+ b0 = 0;
+ bits -= op;
+ }
+
+ wnd->nbits = new_bits;
+ wnd->nwnd = new_wnd;
+ wnd->bits_last = new_last;
+
+ wnd_add_free_ext(wnd, old_bits, new_bits - old_bits, false);
+
+ return 0;
+}
+
+/*
+ * wnd_zone_set
+ */
+void wnd_zone_set(struct wnd_bitmap *wnd, size_t lcn, size_t len)
+{
+ size_t zlen;
+
+ zlen = wnd->zone_end - wnd->zone_bit;
+ if (zlen)
+ wnd_add_free_ext(wnd, wnd->zone_bit, zlen, false);
+
+ if (!RB_EMPTY_ROOT(&wnd->start_tree) && len)
+ wnd_remove_free_ext(wnd, lcn, len);
+
+ wnd->zone_bit = lcn;
+ wnd->zone_end = lcn + len;
+}
+
+int ntfs_trim_fs(struct ntfs_sb_info *sbi, struct fstrim_range *range)
+{
+ int err = 0;
+ struct super_block *sb = sbi->sb;
+ struct wnd_bitmap *wnd = &sbi->used.bitmap;
+ u32 wbits = 8 * sb->s_blocksize;
+ CLST len = 0, lcn = 0, done = 0;
+ CLST minlen = bytes_to_cluster(sbi, range->minlen);
+ CLST lcn_from = bytes_to_cluster(sbi, range->start);
+ size_t iw = lcn_from >> (sb->s_blocksize_bits + 3);
+ u32 wbit = lcn_from & (wbits - 1);
+ const ulong *buf;
+ CLST lcn_to;
+
+ if (!minlen)
+ minlen = 1;
+
+ if (range->len == (u64)-1)
+ lcn_to = wnd->nbits;
+ else
+ lcn_to = bytes_to_cluster(sbi, range->start + range->len);
+
+ down_read_nested(&wnd->rw_lock, BITMAP_MUTEX_CLUSTERS);
+
+ for (; iw < wnd->nbits; iw++, wbit = 0) {
+ CLST lcn_wnd = iw * wbits;
+ struct buffer_head *bh;
+
+ if (lcn_wnd > lcn_to)
+ break;
+
+ if (!wnd->free_bits[iw])
+ continue;
+
+ if (iw + 1 == wnd->nwnd)
+ wbits = wnd->bits_last;
+
+ if (lcn_wnd + wbits > lcn_to)
+ wbits = lcn_to - lcn_wnd;
+
+ bh = wnd_map(wnd, iw);
+ if (IS_ERR(bh)) {
+ err = PTR_ERR(bh);
+ break;
+ }
+
+ buf = (ulong *)bh->b_data;
+
+ for (; wbit < wbits; wbit++) {
+ if (!test_bit(wbit, buf)) {
+ if (!len)
+ lcn = lcn_wnd + wbit;
+ len += 1;
+ continue;
+ }
+ if (len >= minlen) {
+ err = ntfs_discard(sbi, lcn, len);
+ if (err)
+ goto out;
+ done += len;
+ }
+ len = 0;
+ }
+ put_bh(bh);
+ }
+
+ /* Process the last fragment */
+ if (len >= minlen) {
+ err = ntfs_discard(sbi, lcn, len);
+ if (err)
+ goto out;
+ done += len;
+ }
+
+out:
+ range->len = (u64)done << sbi->cluster_bits;
+
+ up_read(&wnd->rw_lock);
+
+ return err;
+}
--
2.25.4
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