1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	*
4	* Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
5	*
6	* This code builds two trees of free clusters extents.
7	* Trees are sorted by start of extent and by length of extent.
8	* NTFS_MAX_WND_EXTENTS defines the maximum number of elements in trees.
9	* In extreme case code reads on-disk bitmap to find free clusters.
10	*
11	*/
12
13	#include <linux/buffer_head.h>
14	#include <linux/fs.h>
15	#include <linux/kernel.h>
16
17	#include "ntfs.h"
18	#include "ntfs_fs.h"
19
20	/*
21	* Maximum number of extents in tree.
22	*/
23	#define NTFS_MAX_WND_EXTENTS (32u * 1024u)
24
25	struct rb_node_key {
26	struct rb_node node;
27	size_t key;
28	};
29
30	struct e_node {
31	struct rb_node_key start; /* Tree sorted by start. */
32	struct rb_node_key count; /* Tree sorted by len. */
33	};
34
35	static int wnd_rescan(struct wnd_bitmap *wnd);
36	static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw);
37	static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits);
38
39	static struct kmem_cache *ntfs_enode_cachep;
40
41	int __init ntfs3_init_bitmap(void)
42	{
43	ntfs_enode_cachep = kmem_cache_create("ntfs3_enode_cache",
44	sizeof(struct e_node), 0,
45	SLAB_RECLAIM_ACCOUNT, NULL);
46	return ntfs_enode_cachep ? 0 : -ENOMEM;
47	}
48
49	void ntfs3_exit_bitmap(void)
50	{
51	kmem_cache_destroy(s: ntfs_enode_cachep);
52	}
53
54	/*
55	* wnd_scan
56	*
57	* b_pos + b_len - biggest fragment.
58	* Scan range [wpos wbits) window @buf.
59	*
60	* Return: -1 if not found.
61	*/
62	static size_t wnd_scan(const void *buf, size_t wbit, u32 wpos, u32 wend,
63	size_t to_alloc, size_t *prev_tail, size_t *b_pos,
64	size_t *b_len)
65	{
66	while (wpos < wend) {
67	size_t free_len;
68	u32 free_bits, end;
69	u32 used = find_next_zero_bit_le(addr: buf, size: wend, offset: wpos);
70
71	if (used >= wend) {
72	if (*b_len < *prev_tail) {
73	*b_pos = wbit - *prev_tail;
74	*b_len = *prev_tail;
75	}
76
77	*prev_tail = 0;
78	return -1;
79	}
80
81	if (used > wpos) {
82	wpos = used;
83	if (*b_len < *prev_tail) {
84	*b_pos = wbit - *prev_tail;
85	*b_len = *prev_tail;
86	}
87
88	*prev_tail = 0;
89	}
90
91	/*
92	* Now we have a fragment [wpos, wend) staring with 0.
93	*/
94	end = wpos + to_alloc - *prev_tail;
95	free_bits = find_next_bit_le(addr: buf, min(end, wend), offset: wpos);
96
97	free_len = *prev_tail + free_bits - wpos;
98
99	if (*b_len < free_len) {
100	*b_pos = wbit + wpos - *prev_tail;
101	*b_len = free_len;
102	}
103
104	if (free_len >= to_alloc)
105	return wbit + wpos - *prev_tail;
106
107	if (free_bits >= wend) {
108	*prev_tail += free_bits - wpos;
109	return -1;
110	}
111
112	wpos = free_bits + 1;
113
114	*prev_tail = 0;
115	}
116
117	return -1;
118	}
119
120	/*
121	* wnd_close - Frees all resources.
122	*/
123	void wnd_close(struct wnd_bitmap *wnd)
124	{
125	struct rb_node *node, *next;
126
127	kvfree(addr: wnd->free_bits);
128	wnd->free_bits = NULL;
129	run_close(run: &wnd->run);
130
131	node = rb_first(root: &wnd->start_tree);
132
133	while (node) {
134	next = rb_next(node);
135	rb_erase(node, &wnd->start_tree);
136	kmem_cache_free(s: ntfs_enode_cachep,
137	rb_entry(node, struct e_node, start.node));
138	node = next;
139	}
140	}
141
142	static struct rb_node *rb_lookup(struct rb_root *root, size_t v)
143	{
144	struct rb_node **p = &root->rb_node;
145	struct rb_node *r = NULL;
146
147	while (*p) {
148	struct rb_node_key *k;
149
150	k = rb_entry(*p, struct rb_node_key, node);
151	if (v < k->key) {
152	p = &(*p)->rb_left;
153	} else if (v > k->key) {
154	r = &k->node;
155	p = &(*p)->rb_right;
156	} else {
157	return &k->node;
158	}
159	}
160
161	return r;
162	}
163
164	/*
165	* rb_insert_count - Helper function to insert special kind of 'count' tree.
166	*/
167	static inline bool rb_insert_count(struct rb_root *root, struct e_node *e)
168	{
169	struct rb_node **p = &root->rb_node;
170	struct rb_node *parent = NULL;
171	size_t e_ckey = e->count.key;
172	size_t e_skey = e->start.key;
173
174	while (*p) {
175	struct e_node *k =
176	rb_entry(parent = *p, struct e_node, count.node);
177
178	if (e_ckey > k->count.key) {
179	p = &(*p)->rb_left;
180	} else if (e_ckey < k->count.key) {
181	p = &(*p)->rb_right;
182	} else if (e_skey < k->start.key) {
183	p = &(*p)->rb_left;
184	} else if (e_skey > k->start.key) {
185	p = &(*p)->rb_right;
186	} else {
187	WARN_ON(1);
188	return false;
189	}
190	}
191
192	rb_link_node(node: &e->count.node, parent, rb_link: p);
193	rb_insert_color(&e->count.node, root);
194	return true;
195	}
196
197	/*
198	* rb_insert_start - Helper function to insert special kind of 'count' tree.
199	*/
200	static inline bool rb_insert_start(struct rb_root *root, struct e_node *e)
201	{
202	struct rb_node **p = &root->rb_node;
203	struct rb_node *parent = NULL;
204	size_t e_skey = e->start.key;
205
206	while (*p) {
207	struct e_node *k;
208
209	parent = *p;
210
211	k = rb_entry(parent, struct e_node, start.node);
212	if (e_skey < k->start.key) {
213	p = &(*p)->rb_left;
214	} else if (e_skey > k->start.key) {
215	p = &(*p)->rb_right;
216	} else {
217	WARN_ON(1);
218	return false;
219	}
220	}
221
222	rb_link_node(node: &e->start.node, parent, rb_link: p);
223	rb_insert_color(&e->start.node, root);
224	return true;
225	}
226
227	/*
228	* wnd_add_free_ext - Adds a new extent of free space.
229	* @build: 1 when building tree.
230	*/
231	static void wnd_add_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len,
232	bool build)
233	{
234	struct e_node *e, *e0 = NULL;
235	size_t ib, end_in = bit + len;
236	struct rb_node *n;
237
238	if (build) {
239	/* Use extent_min to filter too short extents. */
240	if (wnd->count >= NTFS_MAX_WND_EXTENTS &&
241	len <= wnd->extent_min) {
242	wnd->uptodated = -1;
243	return;
244	}
245	} else {
246	/* Try to find extent before 'bit'. */
247	n = rb_lookup(root: &wnd->start_tree, v: bit);
248
249	if (!n) {
250	n = rb_first(root: &wnd->start_tree);
251	} else {
252	e = rb_entry(n, struct e_node, start.node);
253	n = rb_next(n);
254	if (e->start.key + e->count.key == bit) {
255	/* Remove left. */
256	bit = e->start.key;
257	len += e->count.key;
258	rb_erase(&e->start.node, &wnd->start_tree);
259	rb_erase(&e->count.node, &wnd->count_tree);
260	wnd->count -= 1;
261	e0 = e;
262	}
263	}
264
265	while (n) {
266	size_t next_end;
267
268	e = rb_entry(n, struct e_node, start.node);
269	next_end = e->start.key + e->count.key;
270	if (e->start.key > end_in)
271	break;
272
273	/* Remove right. */
274	n = rb_next(n);
275	len += next_end - end_in;
276	end_in = next_end;
277	rb_erase(&e->start.node, &wnd->start_tree);
278	rb_erase(&e->count.node, &wnd->count_tree);
279	wnd->count -= 1;
280
281	if (!e0)
282	e0 = e;
283	else
284	kmem_cache_free(s: ntfs_enode_cachep, objp: e);
285	}
286
287	if (wnd->uptodated != 1) {
288	/* Check bits before 'bit'. */
289	ib = wnd->zone_bit == wnd->zone_end ||
290	bit < wnd->zone_end ?
291	0 :
292	wnd->zone_end;
293
294	while (bit > ib && wnd_is_free_hlp(wnd, bit: bit - 1, bits: 1)) {
295	bit -= 1;
296	len += 1;
297	}
298
299	/* Check bits after 'end_in'. */
300	ib = wnd->zone_bit == wnd->zone_end ||
301	end_in > wnd->zone_bit ?
302	wnd->nbits :
303	wnd->zone_bit;
304
305	while (end_in < ib && wnd_is_free_hlp(wnd, bit: end_in, bits: 1)) {
306	end_in += 1;
307	len += 1;
308	}
309	}
310	}
311	/* Insert new fragment. */
312	if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
313	if (e0)
314	kmem_cache_free(s: ntfs_enode_cachep, objp: e0);
315
316	wnd->uptodated = -1;
317
318	/* Compare with smallest fragment. */
319	n = rb_last(root: &wnd->count_tree);
320	e = rb_entry(n, struct e_node, count.node);
321	if (len <= e->count.key)
322	goto out; /* Do not insert small fragments. */
323
324	if (build) {
325	struct e_node *e2;
326
327	n = rb_prev(n);
328	e2 = rb_entry(n, struct e_node, count.node);
329	/* Smallest fragment will be 'e2->count.key'. */
330	wnd->extent_min = e2->count.key;
331	}
332
333	/* Replace smallest fragment by new one. */
334	rb_erase(&e->start.node, &wnd->start_tree);
335	rb_erase(&e->count.node, &wnd->count_tree);
336	wnd->count -= 1;
337	} else {
338	e = e0 ? e0 : kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
339	if (!e) {
340	wnd->uptodated = -1;
341	goto out;
342	}
343
344	if (build && len <= wnd->extent_min)
345	wnd->extent_min = len;
346	}
347	e->start.key = bit;
348	e->count.key = len;
349	if (len > wnd->extent_max)
350	wnd->extent_max = len;
351
352	rb_insert_start(root: &wnd->start_tree, e);
353	rb_insert_count(root: &wnd->count_tree, e);
354	wnd->count += 1;
355
356	out:;
357	}
358
359	/*
360	* wnd_remove_free_ext - Remove a run from the cached free space.
361	*/
362	static void wnd_remove_free_ext(struct wnd_bitmap *wnd, size_t bit, size_t len)
363	{
364	struct rb_node *n, *n3;
365	struct e_node *e, *e3;
366	size_t end_in = bit + len;
367	size_t end3, end, new_key, new_len, max_new_len;
368
369	/* Try to find extent before 'bit'. */
370	n = rb_lookup(root: &wnd->start_tree, v: bit);
371
372	if (!n)
373	return;
374
375	e = rb_entry(n, struct e_node, start.node);
376	end = e->start.key + e->count.key;
377
378	new_key = new_len = 0;
379	len = e->count.key;
380
381	/* Range [bit,end_in) must be inside 'e' or outside 'e' and 'n'. */
382	if (e->start.key > bit)
383	;
384	else if (end_in <= end) {
385	/* Range [bit,end_in) inside 'e'. */
386	new_key = end_in;
387	new_len = end - end_in;
388	len = bit - e->start.key;
389	} else if (bit > end) {
390	bool bmax = false;
391
392	n3 = rb_next(n);
393
394	while (n3) {
395	e3 = rb_entry(n3, struct e_node, start.node);
396	if (e3->start.key >= end_in)
397	break;
398
399	if (e3->count.key == wnd->extent_max)
400	bmax = true;
401
402	end3 = e3->start.key + e3->count.key;
403	if (end3 > end_in) {
404	e3->start.key = end_in;
405	rb_erase(&e3->count.node, &wnd->count_tree);
406	e3->count.key = end3 - end_in;
407	rb_insert_count(root: &wnd->count_tree, e: e3);
408	break;
409	}
410
411	n3 = rb_next(n3);
412	rb_erase(&e3->start.node, &wnd->start_tree);
413	rb_erase(&e3->count.node, &wnd->count_tree);
414	wnd->count -= 1;
415	kmem_cache_free(s: ntfs_enode_cachep, objp: e3);
416	}
417	if (!bmax)
418	return;
419	n3 = rb_first(root: &wnd->count_tree);
420	wnd->extent_max =
421	n3 ? rb_entry(n3, struct e_node, count.node)->count.key :
422	0;
423	return;
424	}
425
426	if (e->count.key != wnd->extent_max) {
427	;
428	} else if (rb_prev(&e->count.node)) {
429	;
430	} else {
431	n3 = rb_next(&e->count.node);
432	max_new_len = max(len, new_len);
433	if (!n3) {
434	wnd->extent_max = max_new_len;
435	} else {
436	e3 = rb_entry(n3, struct e_node, count.node);
437	wnd->extent_max = max(e3->count.key, max_new_len);
438	}
439	}
440
441	if (!len) {
442	if (new_len) {
443	e->start.key = new_key;
444	rb_erase(&e->count.node, &wnd->count_tree);
445	e->count.key = new_len;
446	rb_insert_count(root: &wnd->count_tree, e);
447	} else {
448	rb_erase(&e->start.node, &wnd->start_tree);
449	rb_erase(&e->count.node, &wnd->count_tree);
450	wnd->count -= 1;
451	kmem_cache_free(s: ntfs_enode_cachep, objp: e);
452	}
453	goto out;
454	}
455	rb_erase(&e->count.node, &wnd->count_tree);
456	e->count.key = len;
457	rb_insert_count(root: &wnd->count_tree, e);
458
459	if (!new_len)
460	goto out;
461
462	if (wnd->count >= NTFS_MAX_WND_EXTENTS) {
463	wnd->uptodated = -1;
464
465	/* Get minimal extent. */
466	e = rb_entry(rb_last(&wnd->count_tree), struct e_node,
467	count.node);
468	if (e->count.key > new_len)
469	goto out;
470
471	/* Replace minimum. */
472	rb_erase(&e->start.node, &wnd->start_tree);
473	rb_erase(&e->count.node, &wnd->count_tree);
474	wnd->count -= 1;
475	} else {
476	e = kmem_cache_alloc(ntfs_enode_cachep, GFP_ATOMIC);
477	if (!e)
478	wnd->uptodated = -1;
479	}
480
481	if (e) {
482	e->start.key = new_key;
483	e->count.key = new_len;
484	rb_insert_start(root: &wnd->start_tree, e);
485	rb_insert_count(root: &wnd->count_tree, e);
486	wnd->count += 1;
487	}
488
489	out:
490	if (!wnd->count && 1 != wnd->uptodated)
491	wnd_rescan(wnd);
492	}
493
494	/*
495	* wnd_rescan - Scan all bitmap. Used while initialization.
496	*/
497	static int wnd_rescan(struct wnd_bitmap *wnd)
498	{
499	int err = 0;
500	size_t prev_tail = 0;
501	struct super_block *sb = wnd->sb;
502	struct ntfs_sb_info *sbi = sb->s_fs_info;
503	u64 lbo, len = 0;
504	u32 blocksize = sb->s_blocksize;
505	u8 cluster_bits = sbi->cluster_bits;
506	u32 wbits = 8 * sb->s_blocksize;
507	u32 used, frb;
508	size_t wpos, wbit, iw, vbo;
509	struct buffer_head *bh = NULL;
510	CLST lcn, clen;
511
512	wnd->uptodated = 0;
513	wnd->extent_max = 0;
514	wnd->extent_min = MINUS_ONE_T;
515	wnd->total_zeroes = 0;
516
517	vbo = 0;
518
519	for (iw = 0; iw < wnd->nwnd; iw++) {
520	if (iw + 1 == wnd->nwnd)
521	wbits = wnd->bits_last;
522
523	if (wnd->inited) {
524	if (!wnd->free_bits[iw]) {
525	/* All ones. */
526	if (prev_tail) {
527	wnd_add_free_ext(wnd,
528	bit: vbo * 8 - prev_tail,
529	len: prev_tail, build: true);
530	prev_tail = 0;
531	}
532	goto next_wnd;
533	}
534	if (wbits == wnd->free_bits[iw]) {
535	/* All zeroes. */
536	prev_tail += wbits;
537	wnd->total_zeroes += wbits;
538	goto next_wnd;
539	}
540	}
541
542	if (!len) {
543	u32 off = vbo & sbi->cluster_mask;
544
545	if (!run_lookup_entry(run: &wnd->run, vcn: vbo >> cluster_bits,
546	lcn: &lcn, len: &clen, NULL)) {
547	err = -ENOENT;
548	goto out;
549	}
550
551	lbo = ((u64)lcn << cluster_bits) + off;
552	len = ((u64)clen << cluster_bits) - off;
553	}
554
555	bh = ntfs_bread(sb, block: lbo >> sb->s_blocksize_bits);
556	if (!bh) {
557	err = -EIO;
558	goto out;
559	}
560
561	used = ntfs_bitmap_weight_le(bitmap: bh->b_data, bits: wbits);
562	if (used < wbits) {
563	frb = wbits - used;
564	wnd->free_bits[iw] = frb;
565	wnd->total_zeroes += frb;
566	}
567
568	wpos = 0;
569	wbit = vbo * 8;
570
571	if (wbit + wbits > wnd->nbits)
572	wbits = wnd->nbits - wbit;
573
574	do {
575	used = find_next_zero_bit_le(addr: bh->b_data, size: wbits, offset: wpos);
576
577	if (used > wpos && prev_tail) {
578	wnd_add_free_ext(wnd, bit: wbit + wpos - prev_tail,
579	len: prev_tail, build: true);
580	prev_tail = 0;
581	}
582
583	wpos = used;
584
585	if (wpos >= wbits) {
586	/* No free blocks. */
587	prev_tail = 0;
588	break;
589	}
590
591	frb = find_next_bit_le(addr: bh->b_data, size: wbits, offset: wpos);
592	if (frb >= wbits) {
593	/* Keep last free block. */
594	prev_tail += frb - wpos;
595	break;
596	}
597
598	wnd_add_free_ext(wnd, bit: wbit + wpos - prev_tail,
599	len: frb + prev_tail - wpos, build: true);
600
601	/* Skip free block and first '1'. */
602	wpos = frb + 1;
603	/* Reset previous tail. */
604	prev_tail = 0;
605	} while (wpos < wbits);
606
607	next_wnd:
608
609	if (bh)
610	put_bh(bh);
611	bh = NULL;
612
613	vbo += blocksize;
614	if (len) {
615	len -= blocksize;
616	lbo += blocksize;
617	}
618	}
619
620	/* Add last block. */
621	if (prev_tail)
622	wnd_add_free_ext(wnd, bit: wnd->nbits - prev_tail, len: prev_tail, build: true);
623
624	/*
625	* Before init cycle wnd->uptodated was 0.
626	* If any errors or limits occurs while initialization then
627	* wnd->uptodated will be -1.
628	* If 'uptodated' is still 0 then Tree is really updated.
629	*/
630	if (!wnd->uptodated)
631	wnd->uptodated = 1;
632
633	if (wnd->zone_bit != wnd->zone_end) {
634	size_t zlen = wnd->zone_end - wnd->zone_bit;
635
636	wnd->zone_end = wnd->zone_bit;
637	wnd_zone_set(wnd, Lcn: wnd->zone_bit, Len: zlen);
638	}
639
640	out:
641	return err;
642	}
643
644	int wnd_init(struct wnd_bitmap *wnd, struct super_block *sb, size_t nbits)
645	{
646	int err;
647	u32 blocksize = sb->s_blocksize;
648	u32 wbits = blocksize * 8;
649
650	init_rwsem(&wnd->rw_lock);
651
652	wnd->sb = sb;
653	wnd->nbits = nbits;
654	wnd->total_zeroes = nbits;
655	wnd->extent_max = MINUS_ONE_T;
656	wnd->zone_bit = wnd->zone_end = 0;
657	wnd->nwnd = bytes_to_block(sb, size: ntfs3_bitmap_size(bits: nbits));
658	wnd->bits_last = nbits & (wbits - 1);
659	if (!wnd->bits_last)
660	wnd->bits_last = wbits;
661
662	wnd->free_bits =
663	kvmalloc_array(wnd->nwnd, sizeof(u16), GFP_KERNEL | __GFP_ZERO);
664
665	if (!wnd->free_bits)
666	return -ENOMEM;
667
668	err = wnd_rescan(wnd);
669	if (err)
670	return err;
671
672	wnd->inited = true;
673
674	return 0;
675	}
676
677	/*
678	* wnd_map - Call sb_bread for requested window.
679	*/
680	static struct buffer_head *wnd_map(struct wnd_bitmap *wnd, size_t iw)
681	{
682	size_t vbo;
683	CLST lcn, clen;
684	struct super_block *sb = wnd->sb;
685	struct ntfs_sb_info *sbi;
686	struct buffer_head *bh;
687	u64 lbo;
688
689	sbi = sb->s_fs_info;
690	vbo = (u64)iw << sb->s_blocksize_bits;
691
692	if (!run_lookup_entry(run: &wnd->run, vcn: vbo >> sbi->cluster_bits, lcn: &lcn, len: &clen,
693	NULL)) {
694	return ERR_PTR(error: -ENOENT);
695	}
696
697	lbo = ((u64)lcn << sbi->cluster_bits) + (vbo & sbi->cluster_mask);
698
699	bh = ntfs_bread(sb: wnd->sb, block: lbo >> sb->s_blocksize_bits);
700	if (!bh)
701	return ERR_PTR(error: -EIO);
702
703	return bh;
704	}
705
706	/*
707	* wnd_set_free - Mark the bits range from bit to bit + bits as free.
708	*/
709	int wnd_set_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
710	{
711	int err = 0;
712	struct super_block *sb = wnd->sb;
713	u32 wbits = 8 * sb->s_blocksize;
714	size_t iw = bit >> (sb->s_blocksize_bits + 3);
715	u32 wbit = bit & (wbits - 1);
716	struct buffer_head *bh;
717	u32 op;
718
719	for (; iw < wnd->nwnd && bits; iw++, bit += op, bits -= op, wbit = 0) {
720	if (iw + 1 == wnd->nwnd)
721	wbits = wnd->bits_last;
722
723	op = min_t(u32, wbits - wbit, bits);
724
725	bh = wnd_map(wnd, iw);
726	if (IS_ERR(ptr: bh)) {
727	err = PTR_ERR(ptr: bh);
728	break;
729	}
730
731	lock_buffer(bh);
732
733	ntfs_bitmap_clear_le(map: bh->b_data, start: wbit, len: op);
734
735	wnd->free_bits[iw] += op;
736	wnd->total_zeroes += op;
737
738	set_buffer_uptodate(bh);
739	mark_buffer_dirty(bh);
740	unlock_buffer(bh);
741	put_bh(bh);
742
743	wnd_add_free_ext(wnd, bit, len: op, build: false);
744	}
745	return err;
746	}
747
748	/*
749	* wnd_set_used - Mark the bits range from bit to bit + bits as used.
750	*/
751	int wnd_set_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
752	{
753	int err = 0;
754	struct super_block *sb = wnd->sb;
755	size_t iw = bit >> (sb->s_blocksize_bits + 3);
756	u32 wbits = 8 * sb->s_blocksize;
757	u32 wbit = bit & (wbits - 1);
758	struct buffer_head *bh;
759	u32 op;
760
761	for (; iw < wnd->nwnd && bits; iw++, bit += op, bits -= op, wbit = 0) {
762	if (unlikely(iw + 1 == wnd->nwnd))
763	wbits = wnd->bits_last;
764
765	op = min_t(u32, wbits - wbit, bits);
766
767	bh = wnd_map(wnd, iw);
768	if (IS_ERR(ptr: bh)) {
769	err = PTR_ERR(ptr: bh);
770	break;
771	}
772
773	lock_buffer(bh);
774
775	ntfs_bitmap_set_le(map: bh->b_data, start: wbit, len: op);
776	wnd->free_bits[iw] -= op;
777	wnd->total_zeroes -= op;
778
779	set_buffer_uptodate(bh);
780	mark_buffer_dirty(bh);
781	unlock_buffer(bh);
782	put_bh(bh);
783
784	if (!RB_EMPTY_ROOT(&wnd->start_tree))
785	wnd_remove_free_ext(wnd, bit, len: op);
786	}
787	return err;
788	}
789
790	/*
791	* wnd_set_used_safe - Mark the bits range from bit to bit + bits as used.
792	*
793	* Unlikely wnd_set_used/wnd_set_free this function is not full trusted.
794	* It scans every bit in bitmap and marks free bit as used.
795	* @done - how many bits were marked as used.
796	*
797	* NOTE: normally *done should be 0.
798	*/
799	int wnd_set_used_safe(struct wnd_bitmap *wnd, size_t bit, size_t bits,
800	size_t *done)
801	{
802	size_t i, from = 0, len = 0;
803	int err = 0;
804
805	*done = 0;
806	for (i = 0; i < bits; i++) {
807	if (wnd_is_free(wnd, bit: bit + i, bits: 1)) {
808	if (!len)
809	from = bit + i;
810	len += 1;
811	} else if (len) {
812	err = wnd_set_used(wnd, bit: from, bits: len);
813	*done += len;
814	len = 0;
815	if (err)
816	break;
817	}
818	}
819
820	if (len) {
821	/* last fragment. */
822	err = wnd_set_used(wnd, bit: from, bits: len);
823	*done += len;
824	}
825	return err;
826	}
827
828	/*
829	* wnd_is_free_hlp
830	*
831	* Return: True if all clusters [bit, bit+bits) are free (bitmap only).
832	*/
833	static bool wnd_is_free_hlp(struct wnd_bitmap *wnd, size_t bit, size_t bits)
834	{
835	struct super_block *sb = wnd->sb;
836	size_t iw = bit >> (sb->s_blocksize_bits + 3);
837	u32 wbits = 8 * sb->s_blocksize;
838	u32 wbit = bit & (wbits - 1);
839	u32 op;
840
841	for (; iw < wnd->nwnd && bits; iw++, bits -= op, wbit = 0) {
842	if (unlikely(iw + 1 == wnd->nwnd))
843	wbits = wnd->bits_last;
844
845	op = min_t(u32, wbits - wbit, bits);
846
847	if (wbits != wnd->free_bits[iw]) {
848	bool ret;
849	struct buffer_head *bh = wnd_map(wnd, iw);
850
851	if (IS_ERR(ptr: bh))
852	return false;
853
854	ret = are_bits_clear(map: bh->b_data, bit: wbit, nbits: op);
855
856	put_bh(bh);
857	if (!ret)
858	return false;
859	}
860	}
861
862	return true;
863	}
864
865	/*
866	* wnd_is_free
867	*
868	* Return: True if all clusters [bit, bit+bits) are free.
869	*/
870	bool wnd_is_free(struct wnd_bitmap *wnd, size_t bit, size_t bits)
871	{
872	bool ret;
873	struct rb_node *n;
874	size_t end;
875	struct e_node *e;
876
877	if (RB_EMPTY_ROOT(&wnd->start_tree))
878	goto use_wnd;
879
880	n = rb_lookup(root: &wnd->start_tree, v: bit);
881	if (!n)
882	goto use_wnd;
883
884	e = rb_entry(n, struct e_node, start.node);
885
886	end = e->start.key + e->count.key;
887
888	if (bit < end && bit + bits <= end)
889	return true;
890
891	use_wnd:
892	ret = wnd_is_free_hlp(wnd, bit, bits);
893
894	return ret;
895	}
896
897	/*
898	* wnd_is_used
899	*
900	* Return: True if all clusters [bit, bit+bits) are used.
901	*/
902	bool wnd_is_used(struct wnd_bitmap *wnd, size_t bit, size_t bits)
903	{
904	bool ret = false;
905	struct super_block *sb = wnd->sb;
906	size_t iw = bit >> (sb->s_blocksize_bits + 3);
907	u32 wbits = 8 * sb->s_blocksize;
908	u32 wbit = bit & (wbits - 1);
909	u32 op;
910	size_t end;
911	struct rb_node *n;
912	struct e_node *e;
913
914	if (RB_EMPTY_ROOT(&wnd->start_tree))
915	goto use_wnd;
916
917	end = bit + bits;
918	n = rb_lookup(root: &wnd->start_tree, v: end - 1);
919	if (!n)
920	goto use_wnd;
921
922	e = rb_entry(n, struct e_node, start.node);
923	if (e->start.key + e->count.key > bit)
924	return false;
925
926	use_wnd:
927	for (; iw < wnd->nwnd && bits; iw++, bits -= op, wbit = 0) {
928	if (unlikely(iw + 1 == wnd->nwnd))
929	wbits = wnd->bits_last;
930
931	op = min_t(u32, wbits - wbit, bits);
932
933	if (wnd->free_bits[iw]) {
934	bool ret;
935	struct buffer_head *bh = wnd_map(wnd, iw);
936
937	if (IS_ERR(ptr: bh))
938	goto out;
939
940	ret = are_bits_set(map: bh->b_data, bit: wbit, nbits: op);
941	put_bh(bh);
942	if (!ret)
943	goto out;
944	}
945	}
946	ret = true;
947
948	out:
949	return ret;
950	}
951
952	/*
953	* wnd_find - Look for free space.
954	*
955	* - flags - BITMAP_FIND_XXX flags
956	*
957	* Return: 0 if not found.
958	*/
959	size_t wnd_find(struct wnd_bitmap *wnd, size_t to_alloc, size_t hint,
960	size_t flags, size_t *allocated)
961	{
962	struct super_block *sb;
963	u32 wbits, wpos, wzbit, wzend;
964	size_t fnd, max_alloc, b_len, b_pos;
965	size_t iw, prev_tail, nwnd, wbit, ebit, zbit, zend;
966	size_t to_alloc0 = to_alloc;
967	const struct e_node *e;
968	const struct rb_node *pr, *cr;
969	u8 log2_bits;
970	bool fbits_valid;
971	struct buffer_head *bh;
972
973	/* Fast checking for available free space. */
974	if (flags & BITMAP_FIND_FULL) {
975	size_t zeroes = wnd_zeroes(wnd);
976
977	zeroes -= wnd->zone_end - wnd->zone_bit;
978	if (zeroes < to_alloc0)
979	goto no_space;
980
981	if (to_alloc0 > wnd->extent_max)
982	goto no_space;
983	} else {
984	if (to_alloc > wnd->extent_max)
985	to_alloc = wnd->extent_max;
986	}
987
988	if (wnd->zone_bit <= hint && hint < wnd->zone_end)
989	hint = wnd->zone_end;
990
991	max_alloc = wnd->nbits;
992	b_len = b_pos = 0;
993
994	if (hint >= max_alloc)
995	hint = 0;
996
997	if (RB_EMPTY_ROOT(&wnd->start_tree)) {
998	if (wnd->uptodated == 1) {
999	/* Extents tree is updated -> No free space. */
1000	goto no_space;
1001	}
1002	goto scan_bitmap;
1003	}
1004
1005	e = NULL;
1006	if (!hint)
1007	goto allocate_biggest;
1008
1009	/* Use hint: Enumerate extents by start >= hint. */
1010	pr = NULL;
1011	cr = wnd->start_tree.rb_node;
1012
1013	for (;;) {
1014	e = rb_entry(cr, struct e_node, start.node);
1015
1016	if (e->start.key == hint)
1017	break;
1018
1019	if (e->start.key < hint) {
1020	pr = cr;
1021	cr = cr->rb_right;
1022	if (!cr)
1023	break;
1024	continue;
1025	}
1026
1027	cr = cr->rb_left;
1028	if (!cr) {
1029	e = pr ? rb_entry(pr, struct e_node, start.node) : NULL;
1030	break;
1031	}
1032	}
1033
1034	if (!e)
1035	goto allocate_biggest;
1036
1037	if (e->start.key + e->count.key > hint) {
1038	/* We have found extension with 'hint' inside. */
1039	size_t len = e->start.key + e->count.key - hint;
1040
1041	if (len >= to_alloc && hint + to_alloc <= max_alloc) {
1042	fnd = hint;
1043	goto found;
1044	}
1045
1046	if (!(flags & BITMAP_FIND_FULL)) {
1047	if (len > to_alloc)
1048	len = to_alloc;
1049
1050	if (hint + len <= max_alloc) {
1051	fnd = hint;
1052	to_alloc = len;
1053	goto found;
1054	}
1055	}
1056	}
1057
1058	allocate_biggest:
1059	/* Allocate from biggest free extent. */
1060	e = rb_entry(rb_first(&wnd->count_tree), struct e_node, count.node);
1061	if (e->count.key != wnd->extent_max)
1062	wnd->extent_max = e->count.key;
1063
1064	if (e->count.key < max_alloc) {
1065	if (e->count.key >= to_alloc) {
1066	;
1067	} else if (flags & BITMAP_FIND_FULL) {
1068	if (e->count.key < to_alloc0) {
1069	/* Biggest free block is less then requested. */
1070	goto no_space;
1071	}
1072	to_alloc = e->count.key;
1073	} else if (-1 != wnd->uptodated) {
1074	to_alloc = e->count.key;
1075	} else {
1076	/* Check if we can use more bits. */
1077	size_t op, max_check;
1078	struct rb_root start_tree;
1079
1080	memcpy(&start_tree, &wnd->start_tree,
1081	sizeof(struct rb_root));
1082	memset(&wnd->start_tree, 0, sizeof(struct rb_root));
1083
1084	max_check = e->start.key + to_alloc;
1085	if (max_check > max_alloc)
1086	max_check = max_alloc;
1087	for (op = e->start.key + e->count.key; op < max_check;
1088	op++) {
1089	if (!wnd_is_free(wnd, bit: op, bits: 1))
1090	break;
1091	}
1092	memcpy(&wnd->start_tree, &start_tree,
1093	sizeof(struct rb_root));
1094	to_alloc = op - e->start.key;
1095	}
1096
1097	/* Prepare to return. */
1098	fnd = e->start.key;
1099	if (e->start.key + to_alloc > max_alloc)
1100	to_alloc = max_alloc - e->start.key;
1101	goto found;
1102	}
1103
1104	if (wnd->uptodated == 1) {
1105	/* Extents tree is updated -> no free space. */
1106	goto no_space;
1107	}
1108
1109	b_len = e->count.key;
1110	b_pos = e->start.key;
1111
1112	scan_bitmap:
1113	sb = wnd->sb;
1114	log2_bits = sb->s_blocksize_bits + 3;
1115
1116	/* At most two ranges [hint, max_alloc) + [0, hint). */
1117	Again:
1118
1119	/* TODO: Optimize request for case nbits > wbits. */
1120	iw = hint >> log2_bits;
1121	wbits = sb->s_blocksize * 8;
1122	wpos = hint & (wbits - 1);
1123	prev_tail = 0;
1124	fbits_valid = true;
1125
1126	if (max_alloc == wnd->nbits) {
1127	nwnd = wnd->nwnd;
1128	} else {
1129	size_t t = max_alloc + wbits - 1;
1130
1131	nwnd = likely(t > max_alloc) ? (t >> log2_bits) : wnd->nwnd;
1132	}
1133
1134	/* Enumerate all windows. */
1135	for (; iw < nwnd; iw++) {
1136	wbit = iw << log2_bits;
1137
1138	if (!wnd->free_bits[iw]) {
1139	if (prev_tail > b_len) {
1140	b_pos = wbit - prev_tail;
1141	b_len = prev_tail;
1142	}
1143
1144	/* Skip full used window. */
1145	prev_tail = 0;
1146	wpos = 0;
1147	continue;
1148	}
1149
1150	if (unlikely(iw + 1 == nwnd)) {
1151	if (max_alloc == wnd->nbits) {
1152	wbits = wnd->bits_last;
1153	} else {
1154	size_t t = max_alloc & (wbits - 1);
1155
1156	if (t) {
1157	wbits = t;
1158	fbits_valid = false;
1159	}
1160	}
1161	}
1162
1163	if (wnd->zone_end > wnd->zone_bit) {
1164	ebit = wbit + wbits;
1165	zbit = max(wnd->zone_bit, wbit);
1166	zend = min(wnd->zone_end, ebit);
1167
1168	/* Here we have a window [wbit, ebit) and zone [zbit, zend). */
1169	if (zend <= zbit) {
1170	/* Zone does not overlap window. */
1171	} else {
1172	wzbit = zbit - wbit;
1173	wzend = zend - wbit;
1174
1175	/* Zone overlaps window. */
1176	if (wnd->free_bits[iw] == wzend - wzbit) {
1177	prev_tail = 0;
1178	wpos = 0;
1179	continue;
1180	}
1181
1182	/* Scan two ranges window: [wbit, zbit) and [zend, ebit). */
1183	bh = wnd_map(wnd, iw);
1184
1185	if (IS_ERR(ptr: bh)) {
1186	/* TODO: Error */
1187	prev_tail = 0;
1188	wpos = 0;
1189	continue;
1190	}
1191
1192	/* Scan range [wbit, zbit). */
1193	if (wpos < wzbit) {
1194	/* Scan range [wpos, zbit). */
1195	fnd = wnd_scan(buf: bh->b_data, wbit, wpos,
1196	wend: wzbit, to_alloc,
1197	prev_tail: &prev_tail, b_pos: &b_pos,
1198	b_len: &b_len);
1199	if (fnd != MINUS_ONE_T) {
1200	put_bh(bh);
1201	goto found;
1202	}
1203	}
1204
1205	prev_tail = 0;
1206
1207	/* Scan range [zend, ebit). */
1208	if (wzend < wbits) {
1209	fnd = wnd_scan(buf: bh->b_data, wbit,
1210	max(wzend, wpos), wend: wbits,
1211	to_alloc, prev_tail: &prev_tail,
1212	b_pos: &b_pos, b_len: &b_len);
1213	if (fnd != MINUS_ONE_T) {
1214	put_bh(bh);
1215	goto found;
1216	}
1217	}
1218
1219	wpos = 0;
1220	put_bh(bh);
1221	continue;
1222	}
1223	}
1224
1225	/* Current window does not overlap zone. */
1226	if (!wpos && fbits_valid && wnd->free_bits[iw] == wbits) {
1227	/* Window is empty. */
1228	if (prev_tail + wbits >= to_alloc) {
1229	fnd = wbit + wpos - prev_tail;
1230	goto found;
1231	}
1232
1233	/* Increase 'prev_tail' and process next window. */
1234	prev_tail += wbits;
1235	wpos = 0;
1236	continue;
1237	}
1238
1239	/* Read window. */
1240	bh = wnd_map(wnd, iw);
1241	if (IS_ERR(ptr: bh)) {
1242	// TODO: Error.
1243	prev_tail = 0;
1244	wpos = 0;
1245	continue;
1246	}
1247
1248	/* Scan range [wpos, eBits). */
1249	fnd = wnd_scan(buf: bh->b_data, wbit, wpos, wend: wbits, to_alloc,
1250	prev_tail: &prev_tail, b_pos: &b_pos, b_len: &b_len);
1251	put_bh(bh);
1252	if (fnd != MINUS_ONE_T)
1253	goto found;
1254	}
1255
1256	if (b_len < prev_tail) {
1257	/* The last fragment. */
1258	b_len = prev_tail;
1259	b_pos = max_alloc - prev_tail;
1260	}
1261
1262	if (hint) {
1263	/*
1264	* We have scanned range [hint max_alloc).
1265	* Prepare to scan range [0 hint + to_alloc).
1266	*/
1267	size_t nextmax = hint + to_alloc;
1268
1269	if (likely(nextmax >= hint) && nextmax < max_alloc)
1270	max_alloc = nextmax;
1271	hint = 0;
1272	goto Again;
1273	}
1274
1275	if (!b_len)
1276	goto no_space;
1277
1278	wnd->extent_max = b_len;
1279
1280	if (flags & BITMAP_FIND_FULL)
1281	goto no_space;
1282
1283	fnd = b_pos;
1284	to_alloc = b_len;
1285
1286	found:
1287	if (flags & BITMAP_FIND_MARK_AS_USED) {
1288	/* TODO: Optimize remove extent (pass 'e'?). */
1289	if (wnd_set_used(wnd, bit: fnd, bits: to_alloc))
1290	goto no_space;
1291	} else if (wnd->extent_max != MINUS_ONE_T &&
1292	to_alloc > wnd->extent_max) {
1293	wnd->extent_max = to_alloc;
1294	}
1295
1296	*allocated = fnd;
1297	return to_alloc;
1298
1299	no_space:
1300	return 0;
1301	}
1302
1303	/*
1304	* wnd_extend - Extend bitmap ($MFT bitmap).
1305	*/
1306	int wnd_extend(struct wnd_bitmap *wnd, size_t new_bits)
1307	{
1308	int err;
1309	struct super_block *sb = wnd->sb;
1310	struct ntfs_sb_info *sbi = sb->s_fs_info;
1311	u32 blocksize = sb->s_blocksize;
1312	u32 wbits = blocksize * 8;
1313	u32 b0, new_last;
1314	size_t bits, iw, new_wnd;
1315	size_t old_bits = wnd->nbits;
1316	u16 *new_free;
1317
1318	if (new_bits <= old_bits)
1319	return -EINVAL;
1320
1321	/* Align to 8 byte boundary. */
1322	new_wnd = bytes_to_block(sb, size: ntfs3_bitmap_size(bits: new_bits));
1323	new_last = new_bits & (wbits - 1);
1324	if (!new_last)
1325	new_last = wbits;
1326
1327	if (new_wnd != wnd->nwnd) {
1328	new_free = kmalloc_array(new_wnd, sizeof(u16), GFP_NOFS);
1329	if (!new_free)
1330	return -ENOMEM;
1331
1332	memcpy(new_free, wnd->free_bits, wnd->nwnd * sizeof(short));
1333	memset(new_free + wnd->nwnd, 0,
1334	(new_wnd - wnd->nwnd) * sizeof(short));
1335	kvfree(addr: wnd->free_bits);
1336	wnd->free_bits = new_free;
1337	}
1338
1339	/* Zero bits [old_bits,new_bits). */
1340	bits = new_bits - old_bits;
1341	b0 = old_bits & (wbits - 1);
1342
1343	for (iw = old_bits >> (sb->s_blocksize_bits + 3); bits; iw += 1) {
1344	u32 op;
1345	size_t frb;
1346	u64 vbo, lbo, bytes;
1347	struct buffer_head *bh;
1348
1349	if (iw + 1 == new_wnd)
1350	wbits = new_last;
1351
1352	op = b0 + bits > wbits ? wbits - b0 : bits;
1353	vbo = (u64)iw * blocksize;
1354
1355	err = ntfs_vbo_to_lbo(sbi, run: &wnd->run, vbo, lbo: &lbo, bytes: &bytes);
1356	if (err)
1357	return err;
1358
1359	bh = ntfs_bread(sb, block: lbo >> sb->s_blocksize_bits);
1360	if (!bh)
1361	return -EIO;
1362
1363	lock_buffer(bh);
1364
1365	ntfs_bitmap_clear_le(map: bh->b_data, start: b0, len: blocksize * 8 - b0);
1366	frb = wbits - ntfs_bitmap_weight_le(bitmap: bh->b_data, bits: wbits);
1367	wnd->total_zeroes += frb - wnd->free_bits[iw];
1368	wnd->free_bits[iw] = frb;
1369
1370	set_buffer_uptodate(bh);
1371	mark_buffer_dirty(bh);
1372	unlock_buffer(bh);
1373	/* err = sync_dirty_buffer(bh); */
1374	put_bh(bh);
1375
1376	b0 = 0;
1377	bits -= op;
1378	}
1379
1380	wnd->nbits = new_bits;
1381	wnd->nwnd = new_wnd;
1382	wnd->bits_last = new_last;
1383
1384	wnd_add_free_ext(wnd, bit: old_bits, len: new_bits - old_bits, build: false);
1385
1386	return 0;
1387	}
1388
1389	void wnd_zone_set(struct wnd_bitmap *wnd, size_t lcn, size_t len)
1390	{
1391	size_t zlen = wnd->zone_end - wnd->zone_bit;
1392
1393	if (zlen)
1394	wnd_add_free_ext(wnd, bit: wnd->zone_bit, len: zlen, build: false);
1395
1396	if (!RB_EMPTY_ROOT(&wnd->start_tree) && len)
1397	wnd_remove_free_ext(wnd, bit: lcn, len);
1398
1399	wnd->zone_bit = lcn;
1400	wnd->zone_end = lcn + len;
1401	}
1402
1403	int ntfs_trim_fs(struct ntfs_sb_info *sbi, struct fstrim_range *range)
1404	{
1405	int err = 0;
1406	struct super_block *sb = sbi->sb;
1407	struct wnd_bitmap *wnd = &sbi->used.bitmap;
1408	u32 wbits = 8 * sb->s_blocksize;
1409	CLST len = 0, lcn = 0, done = 0;
1410	CLST minlen = bytes_to_cluster(sbi, size: range->minlen);
1411	CLST lcn_from = bytes_to_cluster(sbi, size: range->start);
1412	size_t iw = lcn_from >> (sb->s_blocksize_bits + 3);
1413	u32 wbit = lcn_from & (wbits - 1);
1414	CLST lcn_to;
1415
1416	if (!minlen)
1417	minlen = 1;
1418
1419	if (range->len == (u64)-1)
1420	lcn_to = wnd->nbits;
1421	else
1422	lcn_to = bytes_to_cluster(sbi, size: range->start + range->len);
1423
1424	down_read_nested(sem: &wnd->rw_lock, subclass: BITMAP_MUTEX_CLUSTERS);
1425
1426	for (; iw < wnd->nwnd; iw++, wbit = 0) {
1427	CLST lcn_wnd = iw * wbits;
1428	struct buffer_head *bh;
1429
1430	if (lcn_wnd > lcn_to)
1431	break;
1432
1433	if (!wnd->free_bits[iw])
1434	continue;
1435
1436	if (iw + 1 == wnd->nwnd)
1437	wbits = wnd->bits_last;
1438
1439	if (lcn_wnd + wbits > lcn_to)
1440	wbits = lcn_to - lcn_wnd;
1441
1442	bh = wnd_map(wnd, iw);
1443	if (IS_ERR(ptr: bh)) {
1444	err = PTR_ERR(ptr: bh);
1445	break;
1446	}
1447
1448	for (; wbit < wbits; wbit++) {
1449	if (!test_bit_le(nr: wbit, addr: bh->b_data)) {
1450	if (!len)
1451	lcn = lcn_wnd + wbit;
1452	len += 1;
1453	continue;
1454	}
1455	if (len >= minlen) {
1456	err = ntfs_discard(sbi, Lcn: lcn, Len: len);
1457	if (err)
1458	goto out;
1459	done += len;
1460	}
1461	len = 0;
1462	}
1463	put_bh(bh);
1464	}
1465
1466	/* Process the last fragment. */
1467	if (len >= minlen) {
1468	err = ntfs_discard(sbi, Lcn: lcn, Len: len);
1469	if (err)
1470	goto out;
1471	done += len;
1472	}
1473
1474	out:
1475	range->len = (u64)done << sbi->cluster_bits;
1476
1477	up_read(sem: &wnd->rw_lock);
1478
1479	return err;
1480	}
1481
1482	#if BITS_PER_LONG == 64
1483	typedef __le64 bitmap_ulong;
1484	#define cpu_to_ul(x) cpu_to_le64(x)
1485	#define ul_to_cpu(x) le64_to_cpu(x)
1486	#else
1487	typedef __le32 bitmap_ulong;
1488	#define cpu_to_ul(x) cpu_to_le32(x)
1489	#define ul_to_cpu(x) le32_to_cpu(x)
1490	#endif
1491
1492	void ntfs_bitmap_set_le(void *map, unsigned int start, int len)
1493	{
1494	bitmap_ulong *p = (bitmap_ulong *)map + BIT_WORD(start);
1495	const unsigned int size = start + len;
1496	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
1497	bitmap_ulong mask_to_set = cpu_to_ul(BITMAP_FIRST_WORD_MASK(start));
1498
1499	while (len - bits_to_set >= 0) {
1500	*p |= mask_to_set;
1501	len -= bits_to_set;
1502	bits_to_set = BITS_PER_LONG;
1503	mask_to_set = cpu_to_ul(~0UL);
1504	p++;
1505	}
1506	if (len) {
1507	mask_to_set &= cpu_to_ul(BITMAP_LAST_WORD_MASK(size));
1508	*p |= mask_to_set;
1509	}
1510	}
1511
1512	void ntfs_bitmap_clear_le(void *map, unsigned int start, int len)
1513	{
1514	bitmap_ulong *p = (bitmap_ulong *)map + BIT_WORD(start);
1515	const unsigned int size = start + len;
1516	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
1517	bitmap_ulong mask_to_clear = cpu_to_ul(BITMAP_FIRST_WORD_MASK(start));
1518
1519	while (len - bits_to_clear >= 0) {
1520	*p &= ~mask_to_clear;
1521	len -= bits_to_clear;
1522	bits_to_clear = BITS_PER_LONG;
1523	mask_to_clear = cpu_to_ul(~0UL);
1524	p++;
1525	}
1526	if (len) {
1527	mask_to_clear &= cpu_to_ul(BITMAP_LAST_WORD_MASK(size));
1528	*p &= ~mask_to_clear;
1529	}
1530	}
1531
1532	unsigned int ntfs_bitmap_weight_le(const void *bitmap, int bits)
1533	{
1534	const ulong *bmp = bitmap;
1535	unsigned int k, lim = bits / BITS_PER_LONG;
1536	unsigned int w = 0;
1537
1538	for (k = 0; k < lim; k++)
1539	w += hweight_long(w: bmp[k]);
1540
1541	if (bits % BITS_PER_LONG) {
1542	w += hweight_long(ul_to_cpu(((bitmap_ulong *)bitmap)[k]) &
1543	BITMAP_LAST_WORD_MASK(bits));
1544	}
1545
1546	return w;
1547	}
1548