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 */
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 */
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 */
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 */