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Pull altix-mmr into release branch
[deliverable/linux.git] / fs / ntfs / lcnalloc.c
1 /*
2 * lcnalloc.c - Cluster (de)allocation code. Part of the Linux-NTFS project.
3 *
4 * Copyright (c) 2004-2005 Anton Altaparmakov
5 *
6 * This program/include file is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as published
8 * by the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program/include file is distributed in the hope that it will be
12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program (in the main directory of the Linux-NTFS
18 * distribution in the file COPYING); if not, write to the Free Software
19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #ifdef NTFS_RW
23
24 #include <linux/pagemap.h>
25
26 #include "lcnalloc.h"
27 #include "debug.h"
28 #include "bitmap.h"
29 #include "inode.h"
30 #include "volume.h"
31 #include "attrib.h"
32 #include "malloc.h"
33 #include "aops.h"
34 #include "ntfs.h"
35
36 /**
37 * ntfs_cluster_free_from_rl_nolock - free clusters from runlist
38 * @vol: mounted ntfs volume on which to free the clusters
39 * @rl: runlist describing the clusters to free
40 *
41 * Free all the clusters described by the runlist @rl on the volume @vol. In
42 * the case of an error being returned, at least some of the clusters were not
43 * freed.
44 *
45 * Return 0 on success and -errno on error.
46 *
47 * Locking: - The volume lcn bitmap must be locked for writing on entry and is
48 * left locked on return.
49 */
50 int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
51 const runlist_element *rl)
52 {
53 struct inode *lcnbmp_vi = vol->lcnbmp_ino;
54 int ret = 0;
55
56 ntfs_debug("Entering.");
57 if (!rl)
58 return 0;
59 for (; rl->length; rl++) {
60 int err;
61
62 if (rl->lcn < 0)
63 continue;
64 err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length);
65 if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err))
66 ret = err;
67 }
68 ntfs_debug("Done.");
69 return ret;
70 }
71
72 /**
73 * ntfs_cluster_alloc - allocate clusters on an ntfs volume
74 * @vol: mounted ntfs volume on which to allocate the clusters
75 * @start_vcn: vcn to use for the first allocated cluster
76 * @count: number of clusters to allocate
77 * @start_lcn: starting lcn at which to allocate the clusters (or -1 if none)
78 * @zone: zone from which to allocate the clusters
79 *
80 * Allocate @count clusters preferably starting at cluster @start_lcn or at the
81 * current allocator position if @start_lcn is -1, on the mounted ntfs volume
82 * @vol. @zone is either DATA_ZONE for allocation of normal clusters or
83 * MFT_ZONE for allocation of clusters for the master file table, i.e. the
84 * $MFT/$DATA attribute.
85 *
86 * @start_vcn specifies the vcn of the first allocated cluster. This makes
87 * merging the resulting runlist with the old runlist easier.
88 *
89 * You need to check the return value with IS_ERR(). If this is false, the
90 * function was successful and the return value is a runlist describing the
91 * allocated cluster(s). If IS_ERR() is true, the function failed and
92 * PTR_ERR() gives you the error code.
93 *
94 * Notes on the allocation algorithm
95 * =================================
96 *
97 * There are two data zones. First is the area between the end of the mft zone
98 * and the end of the volume, and second is the area between the start of the
99 * volume and the start of the mft zone. On unmodified/standard NTFS 1.x
100 * volumes, the second data zone does not exist due to the mft zone being
101 * expanded to cover the start of the volume in order to reserve space for the
102 * mft bitmap attribute.
103 *
104 * This is not the prettiest function but the complexity stems from the need of
105 * implementing the mft vs data zoned approach and from the fact that we have
106 * access to the lcn bitmap in portions of up to 8192 bytes at a time, so we
107 * need to cope with crossing over boundaries of two buffers. Further, the
108 * fact that the allocator allows for caller supplied hints as to the location
109 * of where allocation should begin and the fact that the allocator keeps track
110 * of where in the data zones the next natural allocation should occur,
111 * contribute to the complexity of the function. But it should all be
112 * worthwhile, because this allocator should: 1) be a full implementation of
113 * the MFT zone approach used by Windows NT, 2) cause reduction in
114 * fragmentation, and 3) be speedy in allocations (the code is not optimized
115 * for speed, but the algorithm is, so further speed improvements are probably
116 * possible).
117 *
118 * FIXME: We should be monitoring cluster allocation and increment the MFT zone
119 * size dynamically but this is something for the future. We will just cause
120 * heavier fragmentation by not doing it and I am not even sure Windows would
121 * grow the MFT zone dynamically, so it might even be correct not to do this.
122 * The overhead in doing dynamic MFT zone expansion would be very large and
123 * unlikely worth the effort. (AIA)
124 *
125 * TODO: I have added in double the required zone position pointer wrap around
126 * logic which can be optimized to having only one of the two logic sets.
127 * However, having the double logic will work fine, but if we have only one of
128 * the sets and we get it wrong somewhere, then we get into trouble, so
129 * removing the duplicate logic requires _very_ careful consideration of _all_
130 * possible code paths. So at least for now, I am leaving the double logic -
131 * better safe than sorry... (AIA)
132 *
133 * Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked
134 * on return.
135 * - This function takes the volume lcn bitmap lock for writing and
136 * modifies the bitmap contents.
137 */
138 runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
139 const s64 count, const LCN start_lcn,
140 const NTFS_CLUSTER_ALLOCATION_ZONES zone)
141 {
142 LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
143 LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
144 s64 clusters;
145 loff_t i_size;
146 struct inode *lcnbmp_vi;
147 runlist_element *rl = NULL;
148 struct address_space *mapping;
149 struct page *page = NULL;
150 u8 *buf, *byte;
151 int err = 0, rlpos, rlsize, buf_size;
152 u8 pass, done_zones, search_zone, need_writeback = 0, bit;
153
154 ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn "
155 "0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn,
156 (unsigned long long)count,
157 (unsigned long long)start_lcn,
158 zone == MFT_ZONE ? "MFT" : "DATA");
159 BUG_ON(!vol);
160 lcnbmp_vi = vol->lcnbmp_ino;
161 BUG_ON(!lcnbmp_vi);
162 BUG_ON(start_vcn < 0);
163 BUG_ON(count < 0);
164 BUG_ON(start_lcn < -1);
165 BUG_ON(zone < FIRST_ZONE);
166 BUG_ON(zone > LAST_ZONE);
167
168 /* Return NULL if @count is zero. */
169 if (!count)
170 return NULL;
171 /* Take the lcnbmp lock for writing. */
172 down_write(&vol->lcnbmp_lock);
173 /*
174 * If no specific @start_lcn was requested, use the current data zone
175 * position, otherwise use the requested @start_lcn but make sure it
176 * lies outside the mft zone. Also set done_zones to 0 (no zones done)
177 * and pass depending on whether we are starting inside a zone (1) or
178 * at the beginning of a zone (2). If requesting from the MFT_ZONE,
179 * we either start at the current position within the mft zone or at
180 * the specified position. If the latter is out of bounds then we start
181 * at the beginning of the MFT_ZONE.
182 */
183 done_zones = 0;
184 pass = 1;
185 /*
186 * zone_start and zone_end are the current search range. search_zone
187 * is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of
188 * volume) and 4 for data zone 2 (start of volume till start of mft
189 * zone).
190 */
191 zone_start = start_lcn;
192 if (zone_start < 0) {
193 if (zone == DATA_ZONE)
194 zone_start = vol->data1_zone_pos;
195 else
196 zone_start = vol->mft_zone_pos;
197 if (!zone_start) {
198 /*
199 * Zone starts at beginning of volume which means a
200 * single pass is sufficient.
201 */
202 pass = 2;
203 }
204 } else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start &&
205 zone_start < vol->mft_zone_end) {
206 zone_start = vol->mft_zone_end;
207 /*
208 * Starting at beginning of data1_zone which means a single
209 * pass in this zone is sufficient.
210 */
211 pass = 2;
212 } else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start ||
213 zone_start >= vol->mft_zone_end)) {
214 zone_start = vol->mft_lcn;
215 if (!vol->mft_zone_end)
216 zone_start = 0;
217 /*
218 * Starting at beginning of volume which means a single pass
219 * is sufficient.
220 */
221 pass = 2;
222 }
223 if (zone == MFT_ZONE) {
224 zone_end = vol->mft_zone_end;
225 search_zone = 1;
226 } else /* if (zone == DATA_ZONE) */ {
227 /* Skip searching the mft zone. */
228 done_zones |= 1;
229 if (zone_start >= vol->mft_zone_end) {
230 zone_end = vol->nr_clusters;
231 search_zone = 2;
232 } else {
233 zone_end = vol->mft_zone_start;
234 search_zone = 4;
235 }
236 }
237 /*
238 * bmp_pos is the current bit position inside the bitmap. We use
239 * bmp_initial_pos to determine whether or not to do a zone switch.
240 */
241 bmp_pos = bmp_initial_pos = zone_start;
242
243 /* Loop until all clusters are allocated, i.e. clusters == 0. */
244 clusters = count;
245 rlpos = rlsize = 0;
246 mapping = lcnbmp_vi->i_mapping;
247 i_size = i_size_read(lcnbmp_vi);
248 while (1) {
249 ntfs_debug("Start of outer while loop: done_zones 0x%x, "
250 "search_zone %i, pass %i, zone_start 0x%llx, "
251 "zone_end 0x%llx, bmp_initial_pos 0x%llx, "
252 "bmp_pos 0x%llx, rlpos %i, rlsize %i.",
253 done_zones, search_zone, pass,
254 (unsigned long long)zone_start,
255 (unsigned long long)zone_end,
256 (unsigned long long)bmp_initial_pos,
257 (unsigned long long)bmp_pos, rlpos, rlsize);
258 /* Loop until we run out of free clusters. */
259 last_read_pos = bmp_pos >> 3;
260 ntfs_debug("last_read_pos 0x%llx.",
261 (unsigned long long)last_read_pos);
262 if (last_read_pos > i_size) {
263 ntfs_debug("End of attribute reached. "
264 "Skipping to zone_pass_done.");
265 goto zone_pass_done;
266 }
267 if (likely(page)) {
268 if (need_writeback) {
269 ntfs_debug("Marking page dirty.");
270 flush_dcache_page(page);
271 set_page_dirty(page);
272 need_writeback = 0;
273 }
274 ntfs_unmap_page(page);
275 }
276 page = ntfs_map_page(mapping, last_read_pos >>
277 PAGE_CACHE_SHIFT);
278 if (IS_ERR(page)) {
279 err = PTR_ERR(page);
280 ntfs_error(vol->sb, "Failed to map page.");
281 goto out;
282 }
283 buf_size = last_read_pos & ~PAGE_CACHE_MASK;
284 buf = page_address(page) + buf_size;
285 buf_size = PAGE_CACHE_SIZE - buf_size;
286 if (unlikely(last_read_pos + buf_size > i_size))
287 buf_size = i_size - last_read_pos;
288 buf_size <<= 3;
289 lcn = bmp_pos & 7;
290 bmp_pos &= ~(LCN)7;
291 ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, "
292 "bmp_pos 0x%llx, need_writeback %i.", buf_size,
293 (unsigned long long)lcn,
294 (unsigned long long)bmp_pos, need_writeback);
295 while (lcn < buf_size && lcn + bmp_pos < zone_end) {
296 byte = buf + (lcn >> 3);
297 ntfs_debug("In inner while loop: buf_size %i, "
298 "lcn 0x%llx, bmp_pos 0x%llx, "
299 "need_writeback %i, byte ofs 0x%x, "
300 "*byte 0x%x.", buf_size,
301 (unsigned long long)lcn,
302 (unsigned long long)bmp_pos,
303 need_writeback,
304 (unsigned int)(lcn >> 3),
305 (unsigned int)*byte);
306 /* Skip full bytes. */
307 if (*byte == 0xff) {
308 lcn = (lcn + 8) & ~(LCN)7;
309 ntfs_debug("Continuing while loop 1.");
310 continue;
311 }
312 bit = 1 << (lcn & 7);
313 ntfs_debug("bit %i.", bit);
314 /* If the bit is already set, go onto the next one. */
315 if (*byte & bit) {
316 lcn++;
317 ntfs_debug("Continuing while loop 2.");
318 continue;
319 }
320 /*
321 * Allocate more memory if needed, including space for
322 * the terminator element.
323 * ntfs_malloc_nofs() operates on whole pages only.
324 */
325 if ((rlpos + 2) * sizeof(*rl) > rlsize) {
326 runlist_element *rl2;
327
328 ntfs_debug("Reallocating memory.");
329 if (!rl)
330 ntfs_debug("First free bit is at LCN "
331 "0x%llx.",
332 (unsigned long long)
333 (lcn + bmp_pos));
334 rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
335 if (unlikely(!rl2)) {
336 err = -ENOMEM;
337 ntfs_error(vol->sb, "Failed to "
338 "allocate memory.");
339 goto out;
340 }
341 memcpy(rl2, rl, rlsize);
342 ntfs_free(rl);
343 rl = rl2;
344 rlsize += PAGE_SIZE;
345 ntfs_debug("Reallocated memory, rlsize 0x%x.",
346 rlsize);
347 }
348 /* Allocate the bitmap bit. */
349 *byte |= bit;
350 /* We need to write this bitmap page to disk. */
351 need_writeback = 1;
352 ntfs_debug("*byte 0x%x, need_writeback is set.",
353 (unsigned int)*byte);
354 /*
355 * Coalesce with previous run if adjacent LCNs.
356 * Otherwise, append a new run.
357 */
358 ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), "
359 "prev_lcn 0x%llx, lcn 0x%llx, "
360 "bmp_pos 0x%llx, prev_run_len 0x%llx, "
361 "rlpos %i.",
362 (unsigned long long)(lcn + bmp_pos),
363 1ULL, (unsigned long long)prev_lcn,
364 (unsigned long long)lcn,
365 (unsigned long long)bmp_pos,
366 (unsigned long long)prev_run_len,
367 rlpos);
368 if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
369 ntfs_debug("Coalescing to run (lcn 0x%llx, "
370 "len 0x%llx).",
371 (unsigned long long)
372 rl[rlpos - 1].lcn,
373 (unsigned long long)
374 rl[rlpos - 1].length);
375 rl[rlpos - 1].length = ++prev_run_len;
376 ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), "
377 "prev_run_len 0x%llx.",
378 (unsigned long long)
379 rl[rlpos - 1].lcn,
380 (unsigned long long)
381 rl[rlpos - 1].length,
382 (unsigned long long)
383 prev_run_len);
384 } else {
385 if (likely(rlpos)) {
386 ntfs_debug("Adding new run, (previous "
387 "run lcn 0x%llx, "
388 "len 0x%llx).",
389 (unsigned long long)
390 rl[rlpos - 1].lcn,
391 (unsigned long long)
392 rl[rlpos - 1].length);
393 rl[rlpos].vcn = rl[rlpos - 1].vcn +
394 prev_run_len;
395 } else {
396 ntfs_debug("Adding new run, is first "
397 "run.");
398 rl[rlpos].vcn = start_vcn;
399 }
400 rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
401 rl[rlpos].length = prev_run_len = 1;
402 rlpos++;
403 }
404 /* Done? */
405 if (!--clusters) {
406 LCN tc;
407 /*
408 * Update the current zone position. Positions
409 * of already scanned zones have been updated
410 * during the respective zone switches.
411 */
412 tc = lcn + bmp_pos + 1;
413 ntfs_debug("Done. Updating current zone "
414 "position, tc 0x%llx, "
415 "search_zone %i.",
416 (unsigned long long)tc,
417 search_zone);
418 switch (search_zone) {
419 case 1:
420 ntfs_debug("Before checks, "
421 "vol->mft_zone_pos "
422 "0x%llx.",
423 (unsigned long long)
424 vol->mft_zone_pos);
425 if (tc >= vol->mft_zone_end) {
426 vol->mft_zone_pos =
427 vol->mft_lcn;
428 if (!vol->mft_zone_end)
429 vol->mft_zone_pos = 0;
430 } else if ((bmp_initial_pos >=
431 vol->mft_zone_pos ||
432 tc > vol->mft_zone_pos)
433 && tc >= vol->mft_lcn)
434 vol->mft_zone_pos = tc;
435 ntfs_debug("After checks, "
436 "vol->mft_zone_pos "
437 "0x%llx.",
438 (unsigned long long)
439 vol->mft_zone_pos);
440 break;
441 case 2:
442 ntfs_debug("Before checks, "
443 "vol->data1_zone_pos "
444 "0x%llx.",
445 (unsigned long long)
446 vol->data1_zone_pos);
447 if (tc >= vol->nr_clusters)
448 vol->data1_zone_pos =
449 vol->mft_zone_end;
450 else if ((bmp_initial_pos >=
451 vol->data1_zone_pos ||
452 tc > vol->data1_zone_pos)
453 && tc >= vol->mft_zone_end)
454 vol->data1_zone_pos = tc;
455 ntfs_debug("After checks, "
456 "vol->data1_zone_pos "
457 "0x%llx.",
458 (unsigned long long)
459 vol->data1_zone_pos);
460 break;
461 case 4:
462 ntfs_debug("Before checks, "
463 "vol->data2_zone_pos "
464 "0x%llx.",
465 (unsigned long long)
466 vol->data2_zone_pos);
467 if (tc >= vol->mft_zone_start)
468 vol->data2_zone_pos = 0;
469 else if (bmp_initial_pos >=
470 vol->data2_zone_pos ||
471 tc > vol->data2_zone_pos)
472 vol->data2_zone_pos = tc;
473 ntfs_debug("After checks, "
474 "vol->data2_zone_pos "
475 "0x%llx.",
476 (unsigned long long)
477 vol->data2_zone_pos);
478 break;
479 default:
480 BUG();
481 }
482 ntfs_debug("Finished. Going to out.");
483 goto out;
484 }
485 lcn++;
486 }
487 bmp_pos += buf_size;
488 ntfs_debug("After inner while loop: buf_size 0x%x, lcn "
489 "0x%llx, bmp_pos 0x%llx, need_writeback %i.",
490 buf_size, (unsigned long long)lcn,
491 (unsigned long long)bmp_pos, need_writeback);
492 if (bmp_pos < zone_end) {
493 ntfs_debug("Continuing outer while loop, "
494 "bmp_pos 0x%llx, zone_end 0x%llx.",
495 (unsigned long long)bmp_pos,
496 (unsigned long long)zone_end);
497 continue;
498 }
499 zone_pass_done: /* Finished with the current zone pass. */
500 ntfs_debug("At zone_pass_done, pass %i.", pass);
501 if (pass == 1) {
502 /*
503 * Now do pass 2, scanning the first part of the zone
504 * we omitted in pass 1.
505 */
506 pass = 2;
507 zone_end = zone_start;
508 switch (search_zone) {
509 case 1: /* mft_zone */
510 zone_start = vol->mft_zone_start;
511 break;
512 case 2: /* data1_zone */
513 zone_start = vol->mft_zone_end;
514 break;
515 case 4: /* data2_zone */
516 zone_start = 0;
517 break;
518 default:
519 BUG();
520 }
521 /* Sanity check. */
522 if (zone_end < zone_start)
523 zone_end = zone_start;
524 bmp_pos = zone_start;
525 ntfs_debug("Continuing outer while loop, pass 2, "
526 "zone_start 0x%llx, zone_end 0x%llx, "
527 "bmp_pos 0x%llx.",
528 (unsigned long long)zone_start,
529 (unsigned long long)zone_end,
530 (unsigned long long)bmp_pos);
531 continue;
532 } /* pass == 2 */
533 done_zones_check:
534 ntfs_debug("At done_zones_check, search_zone %i, done_zones "
535 "before 0x%x, done_zones after 0x%x.",
536 search_zone, done_zones,
537 done_zones | search_zone);
538 done_zones |= search_zone;
539 if (done_zones < 7) {
540 ntfs_debug("Switching zone.");
541 /* Now switch to the next zone we haven't done yet. */
542 pass = 1;
543 switch (search_zone) {
544 case 1:
545 ntfs_debug("Switching from mft zone to data1 "
546 "zone.");
547 /* Update mft zone position. */
548 if (rlpos) {
549 LCN tc;
550
551 ntfs_debug("Before checks, "
552 "vol->mft_zone_pos "
553 "0x%llx.",
554 (unsigned long long)
555 vol->mft_zone_pos);
556 tc = rl[rlpos - 1].lcn +
557 rl[rlpos - 1].length;
558 if (tc >= vol->mft_zone_end) {
559 vol->mft_zone_pos =
560 vol->mft_lcn;
561 if (!vol->mft_zone_end)
562 vol->mft_zone_pos = 0;
563 } else if ((bmp_initial_pos >=
564 vol->mft_zone_pos ||
565 tc > vol->mft_zone_pos)
566 && tc >= vol->mft_lcn)
567 vol->mft_zone_pos = tc;
568 ntfs_debug("After checks, "
569 "vol->mft_zone_pos "
570 "0x%llx.",
571 (unsigned long long)
572 vol->mft_zone_pos);
573 }
574 /* Switch from mft zone to data1 zone. */
575 switch_to_data1_zone: search_zone = 2;
576 zone_start = bmp_initial_pos =
577 vol->data1_zone_pos;
578 zone_end = vol->nr_clusters;
579 if (zone_start == vol->mft_zone_end)
580 pass = 2;
581 if (zone_start >= zone_end) {
582 vol->data1_zone_pos = zone_start =
583 vol->mft_zone_end;
584 pass = 2;
585 }
586 break;
587 case 2:
588 ntfs_debug("Switching from data1 zone to "
589 "data2 zone.");
590 /* Update data1 zone position. */
591 if (rlpos) {
592 LCN tc;
593
594 ntfs_debug("Before checks, "
595 "vol->data1_zone_pos "
596 "0x%llx.",
597 (unsigned long long)
598 vol->data1_zone_pos);
599 tc = rl[rlpos - 1].lcn +
600 rl[rlpos - 1].length;
601 if (tc >= vol->nr_clusters)
602 vol->data1_zone_pos =
603 vol->mft_zone_end;
604 else if ((bmp_initial_pos >=
605 vol->data1_zone_pos ||
606 tc > vol->data1_zone_pos)
607 && tc >= vol->mft_zone_end)
608 vol->data1_zone_pos = tc;
609 ntfs_debug("After checks, "
610 "vol->data1_zone_pos "
611 "0x%llx.",
612 (unsigned long long)
613 vol->data1_zone_pos);
614 }
615 /* Switch from data1 zone to data2 zone. */
616 search_zone = 4;
617 zone_start = bmp_initial_pos =
618 vol->data2_zone_pos;
619 zone_end = vol->mft_zone_start;
620 if (!zone_start)
621 pass = 2;
622 if (zone_start >= zone_end) {
623 vol->data2_zone_pos = zone_start =
624 bmp_initial_pos = 0;
625 pass = 2;
626 }
627 break;
628 case 4:
629 ntfs_debug("Switching from data2 zone to "
630 "data1 zone.");
631 /* Update data2 zone position. */
632 if (rlpos) {
633 LCN tc;
634
635 ntfs_debug("Before checks, "
636 "vol->data2_zone_pos "
637 "0x%llx.",
638 (unsigned long long)
639 vol->data2_zone_pos);
640 tc = rl[rlpos - 1].lcn +
641 rl[rlpos - 1].length;
642 if (tc >= vol->mft_zone_start)
643 vol->data2_zone_pos = 0;
644 else if (bmp_initial_pos >=
645 vol->data2_zone_pos ||
646 tc > vol->data2_zone_pos)
647 vol->data2_zone_pos = tc;
648 ntfs_debug("After checks, "
649 "vol->data2_zone_pos "
650 "0x%llx.",
651 (unsigned long long)
652 vol->data2_zone_pos);
653 }
654 /* Switch from data2 zone to data1 zone. */
655 goto switch_to_data1_zone;
656 default:
657 BUG();
658 }
659 ntfs_debug("After zone switch, search_zone %i, "
660 "pass %i, bmp_initial_pos 0x%llx, "
661 "zone_start 0x%llx, zone_end 0x%llx.",
662 search_zone, pass,
663 (unsigned long long)bmp_initial_pos,
664 (unsigned long long)zone_start,
665 (unsigned long long)zone_end);
666 bmp_pos = zone_start;
667 if (zone_start == zone_end) {
668 ntfs_debug("Empty zone, going to "
669 "done_zones_check.");
670 /* Empty zone. Don't bother searching it. */
671 goto done_zones_check;
672 }
673 ntfs_debug("Continuing outer while loop.");
674 continue;
675 } /* done_zones == 7 */
676 ntfs_debug("All zones are finished.");
677 /*
678 * All zones are finished! If DATA_ZONE, shrink mft zone. If
679 * MFT_ZONE, we have really run out of space.
680 */
681 mft_zone_size = vol->mft_zone_end - vol->mft_zone_start;
682 ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end "
683 "0x%llx, mft_zone_size 0x%llx.",
684 (unsigned long long)vol->mft_zone_start,
685 (unsigned long long)vol->mft_zone_end,
686 (unsigned long long)mft_zone_size);
687 if (zone == MFT_ZONE || mft_zone_size <= 0) {
688 ntfs_debug("No free clusters left, going to out.");
689 /* Really no more space left on device. */
690 err = -ENOSPC;
691 goto out;
692 } /* zone == DATA_ZONE && mft_zone_size > 0 */
693 ntfs_debug("Shrinking mft zone.");
694 zone_end = vol->mft_zone_end;
695 mft_zone_size >>= 1;
696 if (mft_zone_size > 0)
697 vol->mft_zone_end = vol->mft_zone_start + mft_zone_size;
698 else /* mft zone and data2 zone no longer exist. */
699 vol->data2_zone_pos = vol->mft_zone_start =
700 vol->mft_zone_end = 0;
701 if (vol->mft_zone_pos >= vol->mft_zone_end) {
702 vol->mft_zone_pos = vol->mft_lcn;
703 if (!vol->mft_zone_end)
704 vol->mft_zone_pos = 0;
705 }
706 bmp_pos = zone_start = bmp_initial_pos =
707 vol->data1_zone_pos = vol->mft_zone_end;
708 search_zone = 2;
709 pass = 2;
710 done_zones &= ~2;
711 ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, "
712 "vol->mft_zone_start 0x%llx, "
713 "vol->mft_zone_end 0x%llx, "
714 "vol->mft_zone_pos 0x%llx, search_zone 2, "
715 "pass 2, dones_zones 0x%x, zone_start 0x%llx, "
716 "zone_end 0x%llx, vol->data1_zone_pos 0x%llx, "
717 "continuing outer while loop.",
718 (unsigned long long)mft_zone_size,
719 (unsigned long long)vol->mft_zone_start,
720 (unsigned long long)vol->mft_zone_end,
721 (unsigned long long)vol->mft_zone_pos,
722 done_zones, (unsigned long long)zone_start,
723 (unsigned long long)zone_end,
724 (unsigned long long)vol->data1_zone_pos);
725 }
726 ntfs_debug("After outer while loop.");
727 out:
728 ntfs_debug("At out.");
729 /* Add runlist terminator element. */
730 if (likely(rl)) {
731 rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
732 rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
733 rl[rlpos].length = 0;
734 }
735 if (likely(page && !IS_ERR(page))) {
736 if (need_writeback) {
737 ntfs_debug("Marking page dirty.");
738 flush_dcache_page(page);
739 set_page_dirty(page);
740 need_writeback = 0;
741 }
742 ntfs_unmap_page(page);
743 }
744 if (likely(!err)) {
745 up_write(&vol->lcnbmp_lock);
746 ntfs_debug("Done.");
747 return rl;
748 }
749 ntfs_error(vol->sb, "Failed to allocate clusters, aborting "
750 "(error %i).", err);
751 if (rl) {
752 int err2;
753
754 if (err == -ENOSPC)
755 ntfs_debug("Not enough space to complete allocation, "
756 "err -ENOSPC, first free lcn 0x%llx, "
757 "could allocate up to 0x%llx "
758 "clusters.",
759 (unsigned long long)rl[0].lcn,
760 (unsigned long long)(count - clusters));
761 /* Deallocate all allocated clusters. */
762 ntfs_debug("Attempting rollback...");
763 err2 = ntfs_cluster_free_from_rl_nolock(vol, rl);
764 if (err2) {
765 ntfs_error(vol->sb, "Failed to rollback (error %i). "
766 "Leaving inconsistent metadata! "
767 "Unmount and run chkdsk.", err2);
768 NVolSetErrors(vol);
769 }
770 /* Free the runlist. */
771 ntfs_free(rl);
772 } else if (err == -ENOSPC)
773 ntfs_debug("No space left at all, err = -ENOSPC, first free "
774 "lcn = 0x%llx.",
775 (long long)vol->data1_zone_pos);
776 up_write(&vol->lcnbmp_lock);
777 return ERR_PTR(err);
778 }
779
780 /**
781 * __ntfs_cluster_free - free clusters on an ntfs volume
782 * @ni: ntfs inode whose runlist describes the clusters to free
783 * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
784 * @count: number of clusters to free or -1 for all clusters
785 * @is_rollback: true if this is a rollback operation
786 *
787 * Free @count clusters starting at the cluster @start_vcn in the runlist
788 * described by the vfs inode @ni.
789 *
790 * If @count is -1, all clusters from @start_vcn to the end of the runlist are
791 * deallocated. Thus, to completely free all clusters in a runlist, use
792 * @start_vcn = 0 and @count = -1.
793 *
794 * @is_rollback should always be FALSE, it is for internal use to rollback
795 * errors. You probably want to use ntfs_cluster_free() instead.
796 *
797 * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
798 * has to deal with it later.
799 *
800 * Return the number of deallocated clusters (not counting sparse ones) on
801 * success and -errno on error.
802 *
803 * Locking: - The runlist described by @ni must be locked for writing on entry
804 * and is locked on return. Note the runlist may be modified when
805 * needed runlist fragments need to be mapped.
806 * - The volume lcn bitmap must be unlocked on entry and is unlocked
807 * on return.
808 * - This function takes the volume lcn bitmap lock for writing and
809 * modifies the bitmap contents.
810 */
811 s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
812 const BOOL is_rollback)
813 {
814 s64 delta, to_free, total_freed, real_freed;
815 ntfs_volume *vol;
816 struct inode *lcnbmp_vi;
817 runlist_element *rl;
818 int err;
819
820 BUG_ON(!ni);
821 ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count "
822 "0x%llx.%s", ni->mft_no, (unsigned long long)start_vcn,
823 (unsigned long long)count,
824 is_rollback ? " (rollback)" : "");
825 vol = ni->vol;
826 lcnbmp_vi = vol->lcnbmp_ino;
827 BUG_ON(!lcnbmp_vi);
828 BUG_ON(start_vcn < 0);
829 BUG_ON(count < -1);
830 /*
831 * Lock the lcn bitmap for writing but only if not rolling back. We
832 * must hold the lock all the way including through rollback otherwise
833 * rollback is not possible because once we have cleared a bit and
834 * dropped the lock, anyone could have set the bit again, thus
835 * allocating the cluster for another use.
836 */
837 if (likely(!is_rollback))
838 down_write(&vol->lcnbmp_lock);
839
840 total_freed = real_freed = 0;
841
842 rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, TRUE);
843 if (IS_ERR(rl)) {
844 if (!is_rollback)
845 ntfs_error(vol->sb, "Failed to find first runlist "
846 "element (error %li), aborting.",
847 PTR_ERR(rl));
848 err = PTR_ERR(rl);
849 goto err_out;
850 }
851 if (unlikely(rl->lcn < LCN_HOLE)) {
852 if (!is_rollback)
853 ntfs_error(vol->sb, "First runlist element has "
854 "invalid lcn, aborting.");
855 err = -EIO;
856 goto err_out;
857 }
858 /* Find the starting cluster inside the run that needs freeing. */
859 delta = start_vcn - rl->vcn;
860
861 /* The number of clusters in this run that need freeing. */
862 to_free = rl->length - delta;
863 if (count >= 0 && to_free > count)
864 to_free = count;
865
866 if (likely(rl->lcn >= 0)) {
867 /* Do the actual freeing of the clusters in this run. */
868 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta,
869 to_free, likely(!is_rollback) ? 0 : 1);
870 if (unlikely(err)) {
871 if (!is_rollback)
872 ntfs_error(vol->sb, "Failed to clear first run "
873 "(error %i), aborting.", err);
874 goto err_out;
875 }
876 /* We have freed @to_free real clusters. */
877 real_freed = to_free;
878 };
879 /* Go to the next run and adjust the number of clusters left to free. */
880 ++rl;
881 if (count >= 0)
882 count -= to_free;
883
884 /* Keep track of the total "freed" clusters, including sparse ones. */
885 total_freed = to_free;
886 /*
887 * Loop over the remaining runs, using @count as a capping value, and
888 * free them.
889 */
890 for (; rl->length && count != 0; ++rl) {
891 if (unlikely(rl->lcn < LCN_HOLE)) {
892 VCN vcn;
893
894 /* Attempt to map runlist. */
895 vcn = rl->vcn;
896 rl = ntfs_attr_find_vcn_nolock(ni, vcn, TRUE);
897 if (IS_ERR(rl)) {
898 err = PTR_ERR(rl);
899 if (!is_rollback)
900 ntfs_error(vol->sb, "Failed to map "
901 "runlist fragment or "
902 "failed to find "
903 "subsequent runlist "
904 "element.");
905 goto err_out;
906 }
907 if (unlikely(rl->lcn < LCN_HOLE)) {
908 if (!is_rollback)
909 ntfs_error(vol->sb, "Runlist element "
910 "has invalid lcn "
911 "(0x%llx).",
912 (unsigned long long)
913 rl->lcn);
914 err = -EIO;
915 goto err_out;
916 }
917 }
918 /* The number of clusters in this run that need freeing. */
919 to_free = rl->length;
920 if (count >= 0 && to_free > count)
921 to_free = count;
922
923 if (likely(rl->lcn >= 0)) {
924 /* Do the actual freeing of the clusters in the run. */
925 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn,
926 to_free, likely(!is_rollback) ? 0 : 1);
927 if (unlikely(err)) {
928 if (!is_rollback)
929 ntfs_error(vol->sb, "Failed to clear "
930 "subsequent run.");
931 goto err_out;
932 }
933 /* We have freed @to_free real clusters. */
934 real_freed += to_free;
935 }
936 /* Adjust the number of clusters left to free. */
937 if (count >= 0)
938 count -= to_free;
939
940 /* Update the total done clusters. */
941 total_freed += to_free;
942 }
943 if (likely(!is_rollback))
944 up_write(&vol->lcnbmp_lock);
945
946 BUG_ON(count > 0);
947
948 /* We are done. Return the number of actually freed clusters. */
949 ntfs_debug("Done.");
950 return real_freed;
951 err_out:
952 if (is_rollback)
953 return err;
954 /* If no real clusters were freed, no need to rollback. */
955 if (!real_freed) {
956 up_write(&vol->lcnbmp_lock);
957 return err;
958 }
959 /*
960 * Attempt to rollback and if that succeeds just return the error code.
961 * If rollback fails, set the volume errors flag, emit an error
962 * message, and return the error code.
963 */
964 delta = __ntfs_cluster_free(ni, start_vcn, total_freed, TRUE);
965 if (delta < 0) {
966 ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving "
967 "inconsistent metadata! Unmount and run "
968 "chkdsk.", (int)delta);
969 NVolSetErrors(vol);
970 }
971 up_write(&vol->lcnbmp_lock);
972 ntfs_error(vol->sb, "Aborting (error %i).", err);
973 return err;
974 }
975
976 #endif /* NTFS_RW */
Linux kernel - Deliverables
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