1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * lcnalloc.c - Cluster (de)allocation code.  Part of the Linux-NTFS project.
4  *
5  * Copyright (c) 2004-2005 Anton Altaparmakov
6  */
7 
8 #ifdef NTFS_RW
9 
10 #include <linux/pagemap.h>
11 
12 #include "lcnalloc.h"
13 #include "debug.h"
14 #include "bitmap.h"
15 #include "inode.h"
16 #include "volume.h"
17 #include "attrib.h"
18 #include "malloc.h"
19 #include "aops.h"
20 #include "ntfs.h"
21 
22 /**
23  * ntfs_cluster_free_from_rl_nolock - free clusters from runlist
24  * @vol:	mounted ntfs volume on which to free the clusters
25  * @rl:		runlist describing the clusters to free
26  *
27  * Free all the clusters described by the runlist @rl on the volume @vol.  In
28  * the case of an error being returned, at least some of the clusters were not
29  * freed.
30  *
31  * Return 0 on success and -errno on error.
32  *
33  * Locking: - The volume lcn bitmap must be locked for writing on entry and is
34  *	      left locked on return.
35  */
ntfs_cluster_free_from_rl_nolock(ntfs_volume * vol,const runlist_element * rl)36 int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
37 		const runlist_element *rl)
38 {
39 	struct inode *lcnbmp_vi = vol->lcnbmp_ino;
40 	int ret = 0;
41 
42 	ntfs_debug("Entering.");
43 	if (!rl)
44 		return 0;
45 	for (; rl->length; rl++) {
46 		int err;
47 
48 		if (rl->lcn < 0)
49 			continue;
50 		err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length);
51 		if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err))
52 			ret = err;
53 	}
54 	ntfs_debug("Done.");
55 	return ret;
56 }
57 
58 /**
59  * ntfs_cluster_alloc - allocate clusters on an ntfs volume
60  * @vol:	mounted ntfs volume on which to allocate the clusters
61  * @start_vcn:	vcn to use for the first allocated cluster
62  * @count:	number of clusters to allocate
63  * @start_lcn:	starting lcn at which to allocate the clusters (or -1 if none)
64  * @zone:	zone from which to allocate the clusters
65  * @is_extension:	if 'true', this is an attribute extension
66  *
67  * Allocate @count clusters preferably starting at cluster @start_lcn or at the
68  * current allocator position if @start_lcn is -1, on the mounted ntfs volume
69  * @vol. @zone is either DATA_ZONE for allocation of normal clusters or
70  * MFT_ZONE for allocation of clusters for the master file table, i.e. the
71  * $MFT/$DATA attribute.
72  *
73  * @start_vcn specifies the vcn of the first allocated cluster.  This makes
74  * merging the resulting runlist with the old runlist easier.
75  *
76  * If @is_extension is 'true', the caller is allocating clusters to extend an
77  * attribute and if it is 'false', the caller is allocating clusters to fill a
78  * hole in an attribute.  Practically the difference is that if @is_extension
79  * is 'true' the returned runlist will be terminated with LCN_ENOENT and if
80  * @is_extension is 'false' the runlist will be terminated with
81  * LCN_RL_NOT_MAPPED.
82  *
83  * You need to check the return value with IS_ERR().  If this is false, the
84  * function was successful and the return value is a runlist describing the
85  * allocated cluster(s).  If IS_ERR() is true, the function failed and
86  * PTR_ERR() gives you the error code.
87  *
88  * Notes on the allocation algorithm
89  * =================================
90  *
91  * There are two data zones.  First is the area between the end of the mft zone
92  * and the end of the volume, and second is the area between the start of the
93  * volume and the start of the mft zone.  On unmodified/standard NTFS 1.x
94  * volumes, the second data zone does not exist due to the mft zone being
95  * expanded to cover the start of the volume in order to reserve space for the
96  * mft bitmap attribute.
97  *
98  * This is not the prettiest function but the complexity stems from the need of
99  * implementing the mft vs data zoned approach and from the fact that we have
100  * access to the lcn bitmap in portions of up to 8192 bytes at a time, so we
101  * need to cope with crossing over boundaries of two buffers.  Further, the
102  * fact that the allocator allows for caller supplied hints as to the location
103  * of where allocation should begin and the fact that the allocator keeps track
104  * of where in the data zones the next natural allocation should occur,
105  * contribute to the complexity of the function.  But it should all be
106  * worthwhile, because this allocator should: 1) be a full implementation of
107  * the MFT zone approach used by Windows NT, 2) cause reduction in
108  * fragmentation, and 3) be speedy in allocations (the code is not optimized
109  * for speed, but the algorithm is, so further speed improvements are probably
110  * possible).
111  *
112  * FIXME: We should be monitoring cluster allocation and increment the MFT zone
113  * size dynamically but this is something for the future.  We will just cause
114  * heavier fragmentation by not doing it and I am not even sure Windows would
115  * grow the MFT zone dynamically, so it might even be correct not to do this.
116  * The overhead in doing dynamic MFT zone expansion would be very large and
117  * unlikely worth the effort. (AIA)
118  *
119  * TODO: I have added in double the required zone position pointer wrap around
120  * logic which can be optimized to having only one of the two logic sets.
121  * However, having the double logic will work fine, but if we have only one of
122  * the sets and we get it wrong somewhere, then we get into trouble, so
123  * removing the duplicate logic requires _very_ careful consideration of _all_
124  * possible code paths.  So at least for now, I am leaving the double logic -
125  * better safe than sorry... (AIA)
126  *
127  * Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked
128  *	      on return.
129  *	    - This function takes the volume lcn bitmap lock for writing and
130  *	      modifies the bitmap contents.
131  */
ntfs_cluster_alloc(ntfs_volume * vol,const VCN start_vcn,const s64 count,const LCN start_lcn,const NTFS_CLUSTER_ALLOCATION_ZONES zone,const bool is_extension)132 runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
133 		const s64 count, const LCN start_lcn,
134 		const NTFS_CLUSTER_ALLOCATION_ZONES zone,
135 		const bool is_extension)
136 {
137 	LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
138 	LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
139 	s64 clusters;
140 	loff_t i_size;
141 	struct inode *lcnbmp_vi;
142 	runlist_element *rl = NULL;
143 	struct address_space *mapping;
144 	struct page *page = NULL;
145 	u8 *buf, *byte;
146 	int err = 0, rlpos, rlsize, buf_size;
147 	u8 pass, done_zones, search_zone, need_writeback = 0, bit;
148 
149 	ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn "
150 			"0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn,
151 			(unsigned long long)count,
152 			(unsigned long long)start_lcn,
153 			zone == MFT_ZONE ? "MFT" : "DATA");
154 	BUG_ON(!vol);
155 	lcnbmp_vi = vol->lcnbmp_ino;
156 	BUG_ON(!lcnbmp_vi);
157 	BUG_ON(start_vcn < 0);
158 	BUG_ON(count < 0);
159 	BUG_ON(start_lcn < -1);
160 	BUG_ON(zone < FIRST_ZONE);
161 	BUG_ON(zone > LAST_ZONE);
162 
163 	/* Return NULL if @count is zero. */
164 	if (!count)
165 		return NULL;
166 	/* Take the lcnbmp lock for writing. */
167 	down_write(&vol->lcnbmp_lock);
168 	/*
169 	 * If no specific @start_lcn was requested, use the current data zone
170 	 * position, otherwise use the requested @start_lcn but make sure it
171 	 * lies outside the mft zone.  Also set done_zones to 0 (no zones done)
172 	 * and pass depending on whether we are starting inside a zone (1) or
173 	 * at the beginning of a zone (2).  If requesting from the MFT_ZONE,
174 	 * we either start at the current position within the mft zone or at
175 	 * the specified position.  If the latter is out of bounds then we start
176 	 * at the beginning of the MFT_ZONE.
177 	 */
178 	done_zones = 0;
179 	pass = 1;
180 	/*
181 	 * zone_start and zone_end are the current search range.  search_zone
182 	 * is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of
183 	 * volume) and 4 for data zone 2 (start of volume till start of mft
184 	 * zone).
185 	 */
186 	zone_start = start_lcn;
187 	if (zone_start < 0) {
188 		if (zone == DATA_ZONE)
189 			zone_start = vol->data1_zone_pos;
190 		else
191 			zone_start = vol->mft_zone_pos;
192 		if (!zone_start) {
193 			/*
194 			 * Zone starts at beginning of volume which means a
195 			 * single pass is sufficient.
196 			 */
197 			pass = 2;
198 		}
199 	} else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start &&
200 			zone_start < vol->mft_zone_end) {
201 		zone_start = vol->mft_zone_end;
202 		/*
203 		 * Starting at beginning of data1_zone which means a single
204 		 * pass in this zone is sufficient.
205 		 */
206 		pass = 2;
207 	} else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start ||
208 			zone_start >= vol->mft_zone_end)) {
209 		zone_start = vol->mft_lcn;
210 		if (!vol->mft_zone_end)
211 			zone_start = 0;
212 		/*
213 		 * Starting at beginning of volume which means a single pass
214 		 * is sufficient.
215 		 */
216 		pass = 2;
217 	}
218 	if (zone == MFT_ZONE) {
219 		zone_end = vol->mft_zone_end;
220 		search_zone = 1;
221 	} else /* if (zone == DATA_ZONE) */ {
222 		/* Skip searching the mft zone. */
223 		done_zones |= 1;
224 		if (zone_start >= vol->mft_zone_end) {
225 			zone_end = vol->nr_clusters;
226 			search_zone = 2;
227 		} else {
228 			zone_end = vol->mft_zone_start;
229 			search_zone = 4;
230 		}
231 	}
232 	/*
233 	 * bmp_pos is the current bit position inside the bitmap.  We use
234 	 * bmp_initial_pos to determine whether or not to do a zone switch.
235 	 */
236 	bmp_pos = bmp_initial_pos = zone_start;
237 
238 	/* Loop until all clusters are allocated, i.e. clusters == 0. */
239 	clusters = count;
240 	rlpos = rlsize = 0;
241 	mapping = lcnbmp_vi->i_mapping;
242 	i_size = i_size_read(lcnbmp_vi);
243 	while (1) {
244 		ntfs_debug("Start of outer while loop: done_zones 0x%x, "
245 				"search_zone %i, pass %i, zone_start 0x%llx, "
246 				"zone_end 0x%llx, bmp_initial_pos 0x%llx, "
247 				"bmp_pos 0x%llx, rlpos %i, rlsize %i.",
248 				done_zones, search_zone, pass,
249 				(unsigned long long)zone_start,
250 				(unsigned long long)zone_end,
251 				(unsigned long long)bmp_initial_pos,
252 				(unsigned long long)bmp_pos, rlpos, rlsize);
253 		/* Loop until we run out of free clusters. */
254 		last_read_pos = bmp_pos >> 3;
255 		ntfs_debug("last_read_pos 0x%llx.",
256 				(unsigned long long)last_read_pos);
257 		if (last_read_pos > i_size) {
258 			ntfs_debug("End of attribute reached.  "
259 					"Skipping to zone_pass_done.");
260 			goto zone_pass_done;
261 		}
262 		if (likely(page)) {
263 			if (need_writeback) {
264 				ntfs_debug("Marking page dirty.");
265 				flush_dcache_page(page);
266 				set_page_dirty(page);
267 				need_writeback = 0;
268 			}
269 			ntfs_unmap_page(page);
270 		}
271 		page = ntfs_map_page(mapping, last_read_pos >>
272 				PAGE_SHIFT);
273 		if (IS_ERR(page)) {
274 			err = PTR_ERR(page);
275 			ntfs_error(vol->sb, "Failed to map page.");
276 			goto out;
277 		}
278 		buf_size = last_read_pos & ~PAGE_MASK;
279 		buf = page_address(page) + buf_size;
280 		buf_size = PAGE_SIZE - buf_size;
281 		if (unlikely(last_read_pos + buf_size > i_size))
282 			buf_size = i_size - last_read_pos;
283 		buf_size <<= 3;
284 		lcn = bmp_pos & 7;
285 		bmp_pos &= ~(LCN)7;
286 		ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, "
287 				"bmp_pos 0x%llx, need_writeback %i.", buf_size,
288 				(unsigned long long)lcn,
289 				(unsigned long long)bmp_pos, need_writeback);
290 		while (lcn < buf_size && lcn + bmp_pos < zone_end) {
291 			byte = buf + (lcn >> 3);
292 			ntfs_debug("In inner while loop: buf_size %i, "
293 					"lcn 0x%llx, bmp_pos 0x%llx, "
294 					"need_writeback %i, byte ofs 0x%x, "
295 					"*byte 0x%x.", buf_size,
296 					(unsigned long long)lcn,
297 					(unsigned long long)bmp_pos,
298 					need_writeback,
299 					(unsigned int)(lcn >> 3),
300 					(unsigned int)*byte);
301 			/* Skip full bytes. */
302 			if (*byte == 0xff) {
303 				lcn = (lcn + 8) & ~(LCN)7;
304 				ntfs_debug("Continuing while loop 1.");
305 				continue;
306 			}
307 			bit = 1 << (lcn & 7);
308 			ntfs_debug("bit 0x%x.", bit);
309 			/* If the bit is already set, go onto the next one. */
310 			if (*byte & bit) {
311 				lcn++;
312 				ntfs_debug("Continuing while loop 2.");
313 				continue;
314 			}
315 			/*
316 			 * Allocate more memory if needed, including space for
317 			 * the terminator element.
318 			 * ntfs_malloc_nofs() operates on whole pages only.
319 			 */
320 			if ((rlpos + 2) * sizeof(*rl) > rlsize) {
321 				runlist_element *rl2;
322 
323 				ntfs_debug("Reallocating memory.");
324 				if (!rl)
325 					ntfs_debug("First free bit is at LCN "
326 							"0x%llx.",
327 							(unsigned long long)
328 							(lcn + bmp_pos));
329 				rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
330 				if (unlikely(!rl2)) {
331 					err = -ENOMEM;
332 					ntfs_error(vol->sb, "Failed to "
333 							"allocate memory.");
334 					goto out;
335 				}
336 				memcpy(rl2, rl, rlsize);
337 				ntfs_free(rl);
338 				rl = rl2;
339 				rlsize += PAGE_SIZE;
340 				ntfs_debug("Reallocated memory, rlsize 0x%x.",
341 						rlsize);
342 			}
343 			/* Allocate the bitmap bit. */
344 			*byte |= bit;
345 			/* We need to write this bitmap page to disk. */
346 			need_writeback = 1;
347 			ntfs_debug("*byte 0x%x, need_writeback is set.",
348 					(unsigned int)*byte);
349 			/*
350 			 * Coalesce with previous run if adjacent LCNs.
351 			 * Otherwise, append a new run.
352 			 */
353 			ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), "
354 					"prev_lcn 0x%llx, lcn 0x%llx, "
355 					"bmp_pos 0x%llx, prev_run_len 0x%llx, "
356 					"rlpos %i.",
357 					(unsigned long long)(lcn + bmp_pos),
358 					1ULL, (unsigned long long)prev_lcn,
359 					(unsigned long long)lcn,
360 					(unsigned long long)bmp_pos,
361 					(unsigned long long)prev_run_len,
362 					rlpos);
363 			if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
364 				ntfs_debug("Coalescing to run (lcn 0x%llx, "
365 						"len 0x%llx).",
366 						(unsigned long long)
367 						rl[rlpos - 1].lcn,
368 						(unsigned long long)
369 						rl[rlpos - 1].length);
370 				rl[rlpos - 1].length = ++prev_run_len;
371 				ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), "
372 						"prev_run_len 0x%llx.",
373 						(unsigned long long)
374 						rl[rlpos - 1].lcn,
375 						(unsigned long long)
376 						rl[rlpos - 1].length,
377 						(unsigned long long)
378 						prev_run_len);
379 			} else {
380 				if (likely(rlpos)) {
381 					ntfs_debug("Adding new run, (previous "
382 							"run lcn 0x%llx, "
383 							"len 0x%llx).",
384 							(unsigned long long)
385 							rl[rlpos - 1].lcn,
386 							(unsigned long long)
387 							rl[rlpos - 1].length);
388 					rl[rlpos].vcn = rl[rlpos - 1].vcn +
389 							prev_run_len;
390 				} else {
391 					ntfs_debug("Adding new run, is first "
392 							"run.");
393 					rl[rlpos].vcn = start_vcn;
394 				}
395 				rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
396 				rl[rlpos].length = prev_run_len = 1;
397 				rlpos++;
398 			}
399 			/* Done? */
400 			if (!--clusters) {
401 				LCN tc;
402 				/*
403 				 * Update the current zone position.  Positions
404 				 * of already scanned zones have been updated
405 				 * during the respective zone switches.
406 				 */
407 				tc = lcn + bmp_pos + 1;
408 				ntfs_debug("Done. Updating current zone "
409 						"position, tc 0x%llx, "
410 						"search_zone %i.",
411 						(unsigned long long)tc,
412 						search_zone);
413 				switch (search_zone) {
414 				case 1:
415 					ntfs_debug("Before checks, "
416 							"vol->mft_zone_pos "
417 							"0x%llx.",
418 							(unsigned long long)
419 							vol->mft_zone_pos);
420 					if (tc >= vol->mft_zone_end) {
421 						vol->mft_zone_pos =
422 								vol->mft_lcn;
423 						if (!vol->mft_zone_end)
424 							vol->mft_zone_pos = 0;
425 					} else if ((bmp_initial_pos >=
426 							vol->mft_zone_pos ||
427 							tc > vol->mft_zone_pos)
428 							&& tc >= vol->mft_lcn)
429 						vol->mft_zone_pos = tc;
430 					ntfs_debug("After checks, "
431 							"vol->mft_zone_pos "
432 							"0x%llx.",
433 							(unsigned long long)
434 							vol->mft_zone_pos);
435 					break;
436 				case 2:
437 					ntfs_debug("Before checks, "
438 							"vol->data1_zone_pos "
439 							"0x%llx.",
440 							(unsigned long long)
441 							vol->data1_zone_pos);
442 					if (tc >= vol->nr_clusters)
443 						vol->data1_zone_pos =
444 							     vol->mft_zone_end;
445 					else if ((bmp_initial_pos >=
446 						    vol->data1_zone_pos ||
447 						    tc > vol->data1_zone_pos)
448 						    && tc >= vol->mft_zone_end)
449 						vol->data1_zone_pos = tc;
450 					ntfs_debug("After checks, "
451 							"vol->data1_zone_pos "
452 							"0x%llx.",
453 							(unsigned long long)
454 							vol->data1_zone_pos);
455 					break;
456 				case 4:
457 					ntfs_debug("Before checks, "
458 							"vol->data2_zone_pos "
459 							"0x%llx.",
460 							(unsigned long long)
461 							vol->data2_zone_pos);
462 					if (tc >= vol->mft_zone_start)
463 						vol->data2_zone_pos = 0;
464 					else if (bmp_initial_pos >=
465 						      vol->data2_zone_pos ||
466 						      tc > vol->data2_zone_pos)
467 						vol->data2_zone_pos = tc;
468 					ntfs_debug("After checks, "
469 							"vol->data2_zone_pos "
470 							"0x%llx.",
471 							(unsigned long long)
472 							vol->data2_zone_pos);
473 					break;
474 				default:
475 					BUG();
476 				}
477 				ntfs_debug("Finished.  Going to out.");
478 				goto out;
479 			}
480 			lcn++;
481 		}
482 		bmp_pos += buf_size;
483 		ntfs_debug("After inner while loop: buf_size 0x%x, lcn "
484 				"0x%llx, bmp_pos 0x%llx, need_writeback %i.",
485 				buf_size, (unsigned long long)lcn,
486 				(unsigned long long)bmp_pos, need_writeback);
487 		if (bmp_pos < zone_end) {
488 			ntfs_debug("Continuing outer while loop, "
489 					"bmp_pos 0x%llx, zone_end 0x%llx.",
490 					(unsigned long long)bmp_pos,
491 					(unsigned long long)zone_end);
492 			continue;
493 		}
494 zone_pass_done:	/* Finished with the current zone pass. */
495 		ntfs_debug("At zone_pass_done, pass %i.", pass);
496 		if (pass == 1) {
497 			/*
498 			 * Now do pass 2, scanning the first part of the zone
499 			 * we omitted in pass 1.
500 			 */
501 			pass = 2;
502 			zone_end = zone_start;
503 			switch (search_zone) {
504 			case 1: /* mft_zone */
505 				zone_start = vol->mft_zone_start;
506 				break;
507 			case 2: /* data1_zone */
508 				zone_start = vol->mft_zone_end;
509 				break;
510 			case 4: /* data2_zone */
511 				zone_start = 0;
512 				break;
513 			default:
514 				BUG();
515 			}
516 			/* Sanity check. */
517 			if (zone_end < zone_start)
518 				zone_end = zone_start;
519 			bmp_pos = zone_start;
520 			ntfs_debug("Continuing outer while loop, pass 2, "
521 					"zone_start 0x%llx, zone_end 0x%llx, "
522 					"bmp_pos 0x%llx.",
523 					(unsigned long long)zone_start,
524 					(unsigned long long)zone_end,
525 					(unsigned long long)bmp_pos);
526 			continue;
527 		} /* pass == 2 */
528 done_zones_check:
529 		ntfs_debug("At done_zones_check, search_zone %i, done_zones "
530 				"before 0x%x, done_zones after 0x%x.",
531 				search_zone, done_zones,
532 				done_zones | search_zone);
533 		done_zones |= search_zone;
534 		if (done_zones < 7) {
535 			ntfs_debug("Switching zone.");
536 			/* Now switch to the next zone we haven't done yet. */
537 			pass = 1;
538 			switch (search_zone) {
539 			case 1:
540 				ntfs_debug("Switching from mft zone to data1 "
541 						"zone.");
542 				/* Update mft zone position. */
543 				if (rlpos) {
544 					LCN tc;
545 
546 					ntfs_debug("Before checks, "
547 							"vol->mft_zone_pos "
548 							"0x%llx.",
549 							(unsigned long long)
550 							vol->mft_zone_pos);
551 					tc = rl[rlpos - 1].lcn +
552 							rl[rlpos - 1].length;
553 					if (tc >= vol->mft_zone_end) {
554 						vol->mft_zone_pos =
555 								vol->mft_lcn;
556 						if (!vol->mft_zone_end)
557 							vol->mft_zone_pos = 0;
558 					} else if ((bmp_initial_pos >=
559 							vol->mft_zone_pos ||
560 							tc > vol->mft_zone_pos)
561 							&& tc >= vol->mft_lcn)
562 						vol->mft_zone_pos = tc;
563 					ntfs_debug("After checks, "
564 							"vol->mft_zone_pos "
565 							"0x%llx.",
566 							(unsigned long long)
567 							vol->mft_zone_pos);
568 				}
569 				/* Switch from mft zone to data1 zone. */
570 switch_to_data1_zone:		search_zone = 2;
571 				zone_start = bmp_initial_pos =
572 						vol->data1_zone_pos;
573 				zone_end = vol->nr_clusters;
574 				if (zone_start == vol->mft_zone_end)
575 					pass = 2;
576 				if (zone_start >= zone_end) {
577 					vol->data1_zone_pos = zone_start =
578 							vol->mft_zone_end;
579 					pass = 2;
580 				}
581 				break;
582 			case 2:
583 				ntfs_debug("Switching from data1 zone to "
584 						"data2 zone.");
585 				/* Update data1 zone position. */
586 				if (rlpos) {
587 					LCN tc;
588 
589 					ntfs_debug("Before checks, "
590 							"vol->data1_zone_pos "
591 							"0x%llx.",
592 							(unsigned long long)
593 							vol->data1_zone_pos);
594 					tc = rl[rlpos - 1].lcn +
595 							rl[rlpos - 1].length;
596 					if (tc >= vol->nr_clusters)
597 						vol->data1_zone_pos =
598 							     vol->mft_zone_end;
599 					else if ((bmp_initial_pos >=
600 						    vol->data1_zone_pos ||
601 						    tc > vol->data1_zone_pos)
602 						    && tc >= vol->mft_zone_end)
603 						vol->data1_zone_pos = tc;
604 					ntfs_debug("After checks, "
605 							"vol->data1_zone_pos "
606 							"0x%llx.",
607 							(unsigned long long)
608 							vol->data1_zone_pos);
609 				}
610 				/* Switch from data1 zone to data2 zone. */
611 				search_zone = 4;
612 				zone_start = bmp_initial_pos =
613 						vol->data2_zone_pos;
614 				zone_end = vol->mft_zone_start;
615 				if (!zone_start)
616 					pass = 2;
617 				if (zone_start >= zone_end) {
618 					vol->data2_zone_pos = zone_start =
619 							bmp_initial_pos = 0;
620 					pass = 2;
621 				}
622 				break;
623 			case 4:
624 				ntfs_debug("Switching from data2 zone to "
625 						"data1 zone.");
626 				/* Update data2 zone position. */
627 				if (rlpos) {
628 					LCN tc;
629 
630 					ntfs_debug("Before checks, "
631 							"vol->data2_zone_pos "
632 							"0x%llx.",
633 							(unsigned long long)
634 							vol->data2_zone_pos);
635 					tc = rl[rlpos - 1].lcn +
636 							rl[rlpos - 1].length;
637 					if (tc >= vol->mft_zone_start)
638 						vol->data2_zone_pos = 0;
639 					else if (bmp_initial_pos >=
640 						      vol->data2_zone_pos ||
641 						      tc > vol->data2_zone_pos)
642 						vol->data2_zone_pos = tc;
643 					ntfs_debug("After checks, "
644 							"vol->data2_zone_pos "
645 							"0x%llx.",
646 							(unsigned long long)
647 							vol->data2_zone_pos);
648 				}
649 				/* Switch from data2 zone to data1 zone. */
650 				goto switch_to_data1_zone;
651 			default:
652 				BUG();
653 			}
654 			ntfs_debug("After zone switch, search_zone %i, "
655 					"pass %i, bmp_initial_pos 0x%llx, "
656 					"zone_start 0x%llx, zone_end 0x%llx.",
657 					search_zone, pass,
658 					(unsigned long long)bmp_initial_pos,
659 					(unsigned long long)zone_start,
660 					(unsigned long long)zone_end);
661 			bmp_pos = zone_start;
662 			if (zone_start == zone_end) {
663 				ntfs_debug("Empty zone, going to "
664 						"done_zones_check.");
665 				/* Empty zone. Don't bother searching it. */
666 				goto done_zones_check;
667 			}
668 			ntfs_debug("Continuing outer while loop.");
669 			continue;
670 		} /* done_zones == 7 */
671 		ntfs_debug("All zones are finished.");
672 		/*
673 		 * All zones are finished!  If DATA_ZONE, shrink mft zone.  If
674 		 * MFT_ZONE, we have really run out of space.
675 		 */
676 		mft_zone_size = vol->mft_zone_end - vol->mft_zone_start;
677 		ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end "
678 				"0x%llx, mft_zone_size 0x%llx.",
679 				(unsigned long long)vol->mft_zone_start,
680 				(unsigned long long)vol->mft_zone_end,
681 				(unsigned long long)mft_zone_size);
682 		if (zone == MFT_ZONE || mft_zone_size <= 0) {
683 			ntfs_debug("No free clusters left, going to out.");
684 			/* Really no more space left on device. */
685 			err = -ENOSPC;
686 			goto out;
687 		} /* zone == DATA_ZONE && mft_zone_size > 0 */
688 		ntfs_debug("Shrinking mft zone.");
689 		zone_end = vol->mft_zone_end;
690 		mft_zone_size >>= 1;
691 		if (mft_zone_size > 0)
692 			vol->mft_zone_end = vol->mft_zone_start + mft_zone_size;
693 		else /* mft zone and data2 zone no longer exist. */
694 			vol->data2_zone_pos = vol->mft_zone_start =
695 					vol->mft_zone_end = 0;
696 		if (vol->mft_zone_pos >= vol->mft_zone_end) {
697 			vol->mft_zone_pos = vol->mft_lcn;
698 			if (!vol->mft_zone_end)
699 				vol->mft_zone_pos = 0;
700 		}
701 		bmp_pos = zone_start = bmp_initial_pos =
702 				vol->data1_zone_pos = vol->mft_zone_end;
703 		search_zone = 2;
704 		pass = 2;
705 		done_zones &= ~2;
706 		ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, "
707 				"vol->mft_zone_start 0x%llx, "
708 				"vol->mft_zone_end 0x%llx, "
709 				"vol->mft_zone_pos 0x%llx, search_zone 2, "
710 				"pass 2, dones_zones 0x%x, zone_start 0x%llx, "
711 				"zone_end 0x%llx, vol->data1_zone_pos 0x%llx, "
712 				"continuing outer while loop.",
713 				(unsigned long long)mft_zone_size,
714 				(unsigned long long)vol->mft_zone_start,
715 				(unsigned long long)vol->mft_zone_end,
716 				(unsigned long long)vol->mft_zone_pos,
717 				done_zones, (unsigned long long)zone_start,
718 				(unsigned long long)zone_end,
719 				(unsigned long long)vol->data1_zone_pos);
720 	}
721 	ntfs_debug("After outer while loop.");
722 out:
723 	ntfs_debug("At out.");
724 	/* Add runlist terminator element. */
725 	if (likely(rl)) {
726 		rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
727 		rl[rlpos].lcn = is_extension ? LCN_ENOENT : LCN_RL_NOT_MAPPED;
728 		rl[rlpos].length = 0;
729 	}
730 	if (likely(page && !IS_ERR(page))) {
731 		if (need_writeback) {
732 			ntfs_debug("Marking page dirty.");
733 			flush_dcache_page(page);
734 			set_page_dirty(page);
735 			need_writeback = 0;
736 		}
737 		ntfs_unmap_page(page);
738 	}
739 	if (likely(!err)) {
740 		up_write(&vol->lcnbmp_lock);
741 		ntfs_debug("Done.");
742 		return rl;
743 	}
744 	ntfs_error(vol->sb, "Failed to allocate clusters, aborting "
745 			"(error %i).", err);
746 	if (rl) {
747 		int err2;
748 
749 		if (err == -ENOSPC)
750 			ntfs_debug("Not enough space to complete allocation, "
751 					"err -ENOSPC, first free lcn 0x%llx, "
752 					"could allocate up to 0x%llx "
753 					"clusters.",
754 					(unsigned long long)rl[0].lcn,
755 					(unsigned long long)(count - clusters));
756 		/* Deallocate all allocated clusters. */
757 		ntfs_debug("Attempting rollback...");
758 		err2 = ntfs_cluster_free_from_rl_nolock(vol, rl);
759 		if (err2) {
760 			ntfs_error(vol->sb, "Failed to rollback (error %i).  "
761 					"Leaving inconsistent metadata!  "
762 					"Unmount and run chkdsk.", err2);
763 			NVolSetErrors(vol);
764 		}
765 		/* Free the runlist. */
766 		ntfs_free(rl);
767 	} else if (err == -ENOSPC)
768 		ntfs_debug("No space left at all, err = -ENOSPC, first free "
769 				"lcn = 0x%llx.",
770 				(long long)vol->data1_zone_pos);
771 	up_write(&vol->lcnbmp_lock);
772 	return ERR_PTR(err);
773 }
774 
775 /**
776  * __ntfs_cluster_free - free clusters on an ntfs volume
777  * @ni:		ntfs inode whose runlist describes the clusters to free
778  * @start_vcn:	vcn in the runlist of @ni at which to start freeing clusters
779  * @count:	number of clusters to free or -1 for all clusters
780  * @ctx:	active attribute search context if present or NULL if not
781  * @is_rollback:	true if this is a rollback operation
782  *
783  * Free @count clusters starting at the cluster @start_vcn in the runlist
784  * described by the vfs inode @ni.
785  *
786  * If @count is -1, all clusters from @start_vcn to the end of the runlist are
787  * deallocated.  Thus, to completely free all clusters in a runlist, use
788  * @start_vcn = 0 and @count = -1.
789  *
790  * If @ctx is specified, it is an active search context of @ni and its base mft
791  * record.  This is needed when __ntfs_cluster_free() encounters unmapped
792  * runlist fragments and allows their mapping.  If you do not have the mft
793  * record mapped, you can specify @ctx as NULL and __ntfs_cluster_free() will
794  * perform the necessary mapping and unmapping.
795  *
796  * Note, __ntfs_cluster_free() saves the state of @ctx on entry and restores it
797  * before returning.  Thus, @ctx will be left pointing to the same attribute on
798  * return as on entry.  However, the actual pointers in @ctx may point to
799  * different memory locations on return, so you must remember to reset any
800  * cached pointers from the @ctx, i.e. after the call to __ntfs_cluster_free(),
801  * you will probably want to do:
802  *	m = ctx->mrec;
803  *	a = ctx->attr;
804  * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
805  * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
806  *
807  * @is_rollback should always be 'false', it is for internal use to rollback
808  * errors.  You probably want to use ntfs_cluster_free() instead.
809  *
810  * Note, __ntfs_cluster_free() does not modify the runlist, so you have to
811  * remove from the runlist or mark sparse the freed runs later.
812  *
813  * Return the number of deallocated clusters (not counting sparse ones) on
814  * success and -errno on error.
815  *
816  * WARNING: If @ctx is supplied, regardless of whether success or failure is
817  *	    returned, you need to check IS_ERR(@ctx->mrec) and if 'true' the @ctx
818  *	    is no longer valid, i.e. you need to either call
819  *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
820  *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
821  *	    why the mapping of the old inode failed.
822  *
823  * Locking: - The runlist described by @ni must be locked for writing on entry
824  *	      and is locked on return.  Note the runlist may be modified when
825  *	      needed runlist fragments need to be mapped.
826  *	    - The volume lcn bitmap must be unlocked on entry and is unlocked
827  *	      on return.
828  *	    - This function takes the volume lcn bitmap lock for writing and
829  *	      modifies the bitmap contents.
830  *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
831  *	      entry and it will be left unmapped on return.
832  *	    - If @ctx is not NULL, the base mft record must be mapped on entry
833  *	      and it will be left mapped on return.
834  */
__ntfs_cluster_free(ntfs_inode * ni,const VCN start_vcn,s64 count,ntfs_attr_search_ctx * ctx,const bool is_rollback)835 s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
836 		ntfs_attr_search_ctx *ctx, const bool is_rollback)
837 {
838 	s64 delta, to_free, total_freed, real_freed;
839 	ntfs_volume *vol;
840 	struct inode *lcnbmp_vi;
841 	runlist_element *rl;
842 	int err;
843 
844 	BUG_ON(!ni);
845 	ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count "
846 			"0x%llx.%s", ni->mft_no, (unsigned long long)start_vcn,
847 			(unsigned long long)count,
848 			is_rollback ? " (rollback)" : "");
849 	vol = ni->vol;
850 	lcnbmp_vi = vol->lcnbmp_ino;
851 	BUG_ON(!lcnbmp_vi);
852 	BUG_ON(start_vcn < 0);
853 	BUG_ON(count < -1);
854 	/*
855 	 * Lock the lcn bitmap for writing but only if not rolling back.  We
856 	 * must hold the lock all the way including through rollback otherwise
857 	 * rollback is not possible because once we have cleared a bit and
858 	 * dropped the lock, anyone could have set the bit again, thus
859 	 * allocating the cluster for another use.
860 	 */
861 	if (likely(!is_rollback))
862 		down_write(&vol->lcnbmp_lock);
863 
864 	total_freed = real_freed = 0;
865 
866 	rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx);
867 	if (IS_ERR(rl)) {
868 		if (!is_rollback)
869 			ntfs_error(vol->sb, "Failed to find first runlist "
870 					"element (error %li), aborting.",
871 					PTR_ERR(rl));
872 		err = PTR_ERR(rl);
873 		goto err_out;
874 	}
875 	if (unlikely(rl->lcn < LCN_HOLE)) {
876 		if (!is_rollback)
877 			ntfs_error(vol->sb, "First runlist element has "
878 					"invalid lcn, aborting.");
879 		err = -EIO;
880 		goto err_out;
881 	}
882 	/* Find the starting cluster inside the run that needs freeing. */
883 	delta = start_vcn - rl->vcn;
884 
885 	/* The number of clusters in this run that need freeing. */
886 	to_free = rl->length - delta;
887 	if (count >= 0 && to_free > count)
888 		to_free = count;
889 
890 	if (likely(rl->lcn >= 0)) {
891 		/* Do the actual freeing of the clusters in this run. */
892 		err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta,
893 				to_free, likely(!is_rollback) ? 0 : 1);
894 		if (unlikely(err)) {
895 			if (!is_rollback)
896 				ntfs_error(vol->sb, "Failed to clear first run "
897 						"(error %i), aborting.", err);
898 			goto err_out;
899 		}
900 		/* We have freed @to_free real clusters. */
901 		real_freed = to_free;
902 	};
903 	/* Go to the next run and adjust the number of clusters left to free. */
904 	++rl;
905 	if (count >= 0)
906 		count -= to_free;
907 
908 	/* Keep track of the total "freed" clusters, including sparse ones. */
909 	total_freed = to_free;
910 	/*
911 	 * Loop over the remaining runs, using @count as a capping value, and
912 	 * free them.
913 	 */
914 	for (; rl->length && count != 0; ++rl) {
915 		if (unlikely(rl->lcn < LCN_HOLE)) {
916 			VCN vcn;
917 
918 			/* Attempt to map runlist. */
919 			vcn = rl->vcn;
920 			rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx);
921 			if (IS_ERR(rl)) {
922 				err = PTR_ERR(rl);
923 				if (!is_rollback)
924 					ntfs_error(vol->sb, "Failed to map "
925 							"runlist fragment or "
926 							"failed to find "
927 							"subsequent runlist "
928 							"element.");
929 				goto err_out;
930 			}
931 			if (unlikely(rl->lcn < LCN_HOLE)) {
932 				if (!is_rollback)
933 					ntfs_error(vol->sb, "Runlist element "
934 							"has invalid lcn "
935 							"(0x%llx).",
936 							(unsigned long long)
937 							rl->lcn);
938 				err = -EIO;
939 				goto err_out;
940 			}
941 		}
942 		/* The number of clusters in this run that need freeing. */
943 		to_free = rl->length;
944 		if (count >= 0 && to_free > count)
945 			to_free = count;
946 
947 		if (likely(rl->lcn >= 0)) {
948 			/* Do the actual freeing of the clusters in the run. */
949 			err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn,
950 					to_free, likely(!is_rollback) ? 0 : 1);
951 			if (unlikely(err)) {
952 				if (!is_rollback)
953 					ntfs_error(vol->sb, "Failed to clear "
954 							"subsequent run.");
955 				goto err_out;
956 			}
957 			/* We have freed @to_free real clusters. */
958 			real_freed += to_free;
959 		}
960 		/* Adjust the number of clusters left to free. */
961 		if (count >= 0)
962 			count -= to_free;
963 
964 		/* Update the total done clusters. */
965 		total_freed += to_free;
966 	}
967 	if (likely(!is_rollback))
968 		up_write(&vol->lcnbmp_lock);
969 
970 	BUG_ON(count > 0);
971 
972 	/* We are done.  Return the number of actually freed clusters. */
973 	ntfs_debug("Done.");
974 	return real_freed;
975 err_out:
976 	if (is_rollback)
977 		return err;
978 	/* If no real clusters were freed, no need to rollback. */
979 	if (!real_freed) {
980 		up_write(&vol->lcnbmp_lock);
981 		return err;
982 	}
983 	/*
984 	 * Attempt to rollback and if that succeeds just return the error code.
985 	 * If rollback fails, set the volume errors flag, emit an error
986 	 * message, and return the error code.
987 	 */
988 	delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, true);
989 	if (delta < 0) {
990 		ntfs_error(vol->sb, "Failed to rollback (error %i).  Leaving "
991 				"inconsistent metadata!  Unmount and run "
992 				"chkdsk.", (int)delta);
993 		NVolSetErrors(vol);
994 	}
995 	up_write(&vol->lcnbmp_lock);
996 	ntfs_error(vol->sb, "Aborting (error %i).", err);
997 	return err;
998 }
999 
1000 #endif /* NTFS_RW */
1001