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[PATCH] Speedup FAT filesystem directory reads
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ntfs / lcnalloc.c
bloba4bc07616e5dd5afe4d6ede562b3dfff7f0d7169
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 for (; rl->length; rl++) {
58 int err;
59
60 if (rl->lcn < 0)
61 continue;
62 err = ntfs_bitmap_clear_run(lcnbmp_vi, rl->lcn, rl->length);
63 if (unlikely(err && (!ret || ret == -ENOMEM) && ret != err))
64 ret = err;
65 }
66 ntfs_debug("Done.");
67 return ret;
68 }
69
70 /**
71 * ntfs_cluster_alloc - allocate clusters on an ntfs volume
72 * @vol: mounted ntfs volume on which to allocate the clusters
73 * @start_vcn: vcn to use for the first allocated cluster
74 * @count: number of clusters to allocate
75 * @start_lcn: starting lcn at which to allocate the clusters (or -1 if none)
76 * @zone: zone from which to allocate the clusters
77 *
78 * Allocate @count clusters preferably starting at cluster @start_lcn or at the
79 * current allocator position if @start_lcn is -1, on the mounted ntfs volume
80 * @vol. @zone is either DATA_ZONE for allocation of normal clusters or
81 * MFT_ZONE for allocation of clusters for the master file table, i.e. the
82 * $MFT/$DATA attribute.
83 *
84 * @start_vcn specifies the vcn of the first allocated cluster. This makes
85 * merging the resulting runlist with the old runlist easier.
86 *
87 * You need to check the return value with IS_ERR(). If this is false, the
88 * function was successful and the return value is a runlist describing the
89 * allocated cluster(s). If IS_ERR() is true, the function failed and
90 * PTR_ERR() gives you the error code.
91 *
92 * Notes on the allocation algorithm
93 * =================================
94 *
95 * There are two data zones. First is the area between the end of the mft zone
96 * and the end of the volume, and second is the area between the start of the
97 * volume and the start of the mft zone. On unmodified/standard NTFS 1.x
98 * volumes, the second data zone does not exist due to the mft zone being
99 * expanded to cover the start of the volume in order to reserve space for the
100 * mft bitmap attribute.
101 *
102 * This is not the prettiest function but the complexity stems from the need of
103 * implementing the mft vs data zoned approach and from the fact that we have
104 * access to the lcn bitmap in portions of up to 8192 bytes at a time, so we
105 * need to cope with crossing over boundaries of two buffers. Further, the
106 * fact that the allocator allows for caller supplied hints as to the location
107 * of where allocation should begin and the fact that the allocator keeps track
108 * of where in the data zones the next natural allocation should occur,
109 * contribute to the complexity of the function. But it should all be
110 * worthwhile, because this allocator should: 1) be a full implementation of
111 * the MFT zone approach used by Windows NT, 2) cause reduction in
112 * fragmentation, and 3) be speedy in allocations (the code is not optimized
113 * for speed, but the algorithm is, so further speed improvements are probably
114 * possible).
115 *
116 * FIXME: We should be monitoring cluster allocation and increment the MFT zone
117 * size dynamically but this is something for the future. We will just cause
118 * heavier fragmentation by not doing it and I am not even sure Windows would
119 * grow the MFT zone dynamically, so it might even be correct not to do this.
120 * The overhead in doing dynamic MFT zone expansion would be very large and
121 * unlikely worth the effort. (AIA)
122 *
123 * TODO: I have added in double the required zone position pointer wrap around
124 * logic which can be optimized to having only one of the two logic sets.
125 * However, having the double logic will work fine, but if we have only one of
126 * the sets and we get it wrong somewhere, then we get into trouble, so
127 * removing the duplicate logic requires _very_ careful consideration of _all_
128 * possible code paths. So at least for now, I am leaving the double logic -
129 * better safe than sorry... (AIA)
130 *
131 * Locking: - The volume lcn bitmap must be unlocked on entry and is unlocked
132 * on return.
133 * - This function takes the volume lcn bitmap lock for writing and
134 * modifies the bitmap contents.
135 */
136 runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
137 const s64 count, const LCN start_lcn,
138 const NTFS_CLUSTER_ALLOCATION_ZONES zone)
139 {
140 LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
141 LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
142 s64 clusters;
143 loff_t i_size;
144 struct inode *lcnbmp_vi;
145 runlist_element *rl = NULL;
146 struct address_space *mapping;
147 struct page *page = NULL;
148 u8 *buf, *byte;
149 int err = 0, rlpos, rlsize, buf_size;
150 u8 pass, done_zones, search_zone, need_writeback = 0, bit;
151
152 ntfs_debug("Entering for start_vcn 0x%llx, count 0x%llx, start_lcn "
153 "0x%llx, zone %s_ZONE.", (unsigned long long)start_vcn,
154 (unsigned long long)count,
155 (unsigned long long)start_lcn,
156 zone == MFT_ZONE ? "MFT" : "DATA");
157 BUG_ON(!vol);
158 lcnbmp_vi = vol->lcnbmp_ino;
159 BUG_ON(!lcnbmp_vi);
160 BUG_ON(start_vcn < 0);
161 BUG_ON(count < 0);
162 BUG_ON(start_lcn < -1);
163 BUG_ON(zone < FIRST_ZONE);
164 BUG_ON(zone > LAST_ZONE);
165
166 /* Return empty runlist if @count == 0 */
167 // FIXME: Do we want to just return NULL instead? (AIA)
168 if (!count) {
169 rl = ntfs_malloc_nofs(PAGE_SIZE);
170 if (!rl)
171 return ERR_PTR(-ENOMEM);
172 rl[0].vcn = start_vcn;
173 rl[0].lcn = LCN_RL_NOT_MAPPED;
174 rl[0].length = 0;
175 return rl;
176 }
177 /* Take the lcnbmp lock for writing. */
178 down_write(&vol->lcnbmp_lock);
179 /*
180 * If no specific @start_lcn was requested, use the current data zone
181 * position, otherwise use the requested @start_lcn but make sure it
182 * lies outside the mft zone. Also set done_zones to 0 (no zones done)
183 * and pass depending on whether we are starting inside a zone (1) or
184 * at the beginning of a zone (2). If requesting from the MFT_ZONE,
185 * we either start at the current position within the mft zone or at
186 * the specified position. If the latter is out of bounds then we start
187 * at the beginning of the MFT_ZONE.
188 */
189 done_zones = 0;
190 pass = 1;
191 /*
192 * zone_start and zone_end are the current search range. search_zone
193 * is 1 for mft zone, 2 for data zone 1 (end of mft zone till end of
194 * volume) and 4 for data zone 2 (start of volume till start of mft
195 * zone).
196 */
197 zone_start = start_lcn;
198 if (zone_start < 0) {
199 if (zone == DATA_ZONE)
200 zone_start = vol->data1_zone_pos;
201 else
202 zone_start = vol->mft_zone_pos;
203 if (!zone_start) {
204 /*
205 * Zone starts at beginning of volume which means a
206 * single pass is sufficient.
207 */
208 pass = 2;
209 }
210 } else if (zone == DATA_ZONE && zone_start >= vol->mft_zone_start &&
211 zone_start < vol->mft_zone_end) {
212 zone_start = vol->mft_zone_end;
213 /*
214 * Starting at beginning of data1_zone which means a single
215 * pass in this zone is sufficient.
216 */
217 pass = 2;
218 } else if (zone == MFT_ZONE && (zone_start < vol->mft_zone_start ||
219 zone_start >= vol->mft_zone_end)) {
220 zone_start = vol->mft_lcn;
221 if (!vol->mft_zone_end)
222 zone_start = 0;
223 /*
224 * Starting at beginning of volume which means a single pass
225 * is sufficient.
226 */
227 pass = 2;
228 }
229 if (zone == MFT_ZONE) {
230 zone_end = vol->mft_zone_end;
231 search_zone = 1;
232 } else /* if (zone == DATA_ZONE) */ {
233 /* Skip searching the mft zone. */
234 done_zones |= 1;
235 if (zone_start >= vol->mft_zone_end) {
236 zone_end = vol->nr_clusters;
237 search_zone = 2;
238 } else {
239 zone_end = vol->mft_zone_start;
240 search_zone = 4;
241 }
242 }
243 /*
244 * bmp_pos is the current bit position inside the bitmap. We use
245 * bmp_initial_pos to determine whether or not to do a zone switch.
246 */
247 bmp_pos = bmp_initial_pos = zone_start;
248
249 /* Loop until all clusters are allocated, i.e. clusters == 0. */
250 clusters = count;
251 rlpos = rlsize = 0;
252 mapping = lcnbmp_vi->i_mapping;
253 i_size = i_size_read(lcnbmp_vi);
254 while (1) {
255 ntfs_debug("Start of outer while loop: done_zones 0x%x, "
256 "search_zone %i, pass %i, zone_start 0x%llx, "
257 "zone_end 0x%llx, bmp_initial_pos 0x%llx, "
258 "bmp_pos 0x%llx, rlpos %i, rlsize %i.",
259 done_zones, search_zone, pass,
260 (unsigned long long)zone_start,
261 (unsigned long long)zone_end,
262 (unsigned long long)bmp_initial_pos,
263 (unsigned long long)bmp_pos, rlpos, rlsize);
264 /* Loop until we run out of free clusters. */
265 last_read_pos = bmp_pos >> 3;
266 ntfs_debug("last_read_pos 0x%llx.",
267 (unsigned long long)last_read_pos);
268 if (last_read_pos > i_size) {
269 ntfs_debug("End of attribute reached. "
270 "Skipping to zone_pass_done.");
271 goto zone_pass_done;
272 }
273 if (likely(page)) {
274 if (need_writeback) {
275 ntfs_debug("Marking page dirty.");
276 flush_dcache_page(page);
277 set_page_dirty(page);
278 need_writeback = 0;
279 }
280 ntfs_unmap_page(page);
281 }
282 page = ntfs_map_page(mapping, last_read_pos >>
283 PAGE_CACHE_SHIFT);
284 if (IS_ERR(page)) {
285 err = PTR_ERR(page);
286 ntfs_error(vol->sb, "Failed to map page.");
287 goto out;
288 }
289 buf_size = last_read_pos & ~PAGE_CACHE_MASK;
290 buf = page_address(page) + buf_size;
291 buf_size = PAGE_CACHE_SIZE - buf_size;
292 if (unlikely(last_read_pos + buf_size > i_size))
293 buf_size = i_size - last_read_pos;
294 buf_size <<= 3;
295 lcn = bmp_pos & 7;
296 bmp_pos &= ~(LCN)7;
297 ntfs_debug("Before inner while loop: buf_size %i, lcn 0x%llx, "
298 "bmp_pos 0x%llx, need_writeback %i.", buf_size,
299 (unsigned long long)lcn,
300 (unsigned long long)bmp_pos, need_writeback);
301 while (lcn < buf_size && lcn + bmp_pos < zone_end) {
302 byte = buf + (lcn >> 3);
303 ntfs_debug("In inner while loop: buf_size %i, "
304 "lcn 0x%llx, bmp_pos 0x%llx, "
305 "need_writeback %i, byte ofs 0x%x, "
306 "*byte 0x%x.", buf_size,
307 (unsigned long long)lcn,
308 (unsigned long long)bmp_pos,
309 need_writeback,
310 (unsigned int)(lcn >> 3),
311 (unsigned int)*byte);
312 /* Skip full bytes. */
313 if (*byte == 0xff) {
314 lcn = (lcn + 8) & ~(LCN)7;
315 ntfs_debug("Continuing while loop 1.");
316 continue;
317 }
318 bit = 1 << (lcn & 7);
319 ntfs_debug("bit %i.", bit);
320 /* If the bit is already set, go onto the next one. */
321 if (*byte & bit) {
322 lcn++;
323 ntfs_debug("Continuing while loop 2.");
324 continue;
325 }
326 /*
327 * Allocate more memory if needed, including space for
328 * the terminator element.
329 * ntfs_malloc_nofs() operates on whole pages only.
330 */
331 if ((rlpos + 2) * sizeof(*rl) > rlsize) {
332 runlist_element *rl2;
333
334 ntfs_debug("Reallocating memory.");
335 if (!rl)
336 ntfs_debug("First free bit is at LCN "
337 "0x%llx.",
338 (unsigned long long)
339 (lcn + bmp_pos));
340 rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
341 if (unlikely(!rl2)) {
342 err = -ENOMEM;
343 ntfs_error(vol->sb, "Failed to "
344 "allocate memory.");
345 goto out;
346 }
347 memcpy(rl2, rl, rlsize);
348 ntfs_free(rl);
349 rl = rl2;
350 rlsize += PAGE_SIZE;
351 ntfs_debug("Reallocated memory, rlsize 0x%x.",
352 rlsize);
353 }
354 /* Allocate the bitmap bit. */
355 *byte |= bit;
356 /* We need to write this bitmap page to disk. */
357 need_writeback = 1;
358 ntfs_debug("*byte 0x%x, need_writeback is set.",
359 (unsigned int)*byte);
360 /*
361 * Coalesce with previous run if adjacent LCNs.
362 * Otherwise, append a new run.
363 */
364 ntfs_debug("Adding run (lcn 0x%llx, len 0x%llx), "
365 "prev_lcn 0x%llx, lcn 0x%llx, "
366 "bmp_pos 0x%llx, prev_run_len 0x%llx, "
367 "rlpos %i.",
368 (unsigned long long)(lcn + bmp_pos),
369 1ULL, (unsigned long long)prev_lcn,
370 (unsigned long long)lcn,
371 (unsigned long long)bmp_pos,
372 (unsigned long long)prev_run_len,
373 rlpos);
374 if (prev_lcn == lcn + bmp_pos - prev_run_len && rlpos) {
375 ntfs_debug("Coalescing to run (lcn 0x%llx, "
376 "len 0x%llx).",
377 (unsigned long long)
378 rl[rlpos - 1].lcn,
379 (unsigned long long)
380 rl[rlpos - 1].length);
381 rl[rlpos - 1].length = ++prev_run_len;
382 ntfs_debug("Run now (lcn 0x%llx, len 0x%llx), "
383 "prev_run_len 0x%llx.",
384 (unsigned long long)
385 rl[rlpos - 1].lcn,
386 (unsigned long long)
387 rl[rlpos - 1].length,
388 (unsigned long long)
389 prev_run_len);
390 } else {
391 if (likely(rlpos)) {
392 ntfs_debug("Adding new run, (previous "
393 "run lcn 0x%llx, "
394 "len 0x%llx).",
395 (unsigned long long)
396 rl[rlpos - 1].lcn,
397 (unsigned long long)
398 rl[rlpos - 1].length);
399 rl[rlpos].vcn = rl[rlpos - 1].vcn +
400 prev_run_len;
401 } else {
402 ntfs_debug("Adding new run, is first "
403 "run.");
404 rl[rlpos].vcn = start_vcn;
405 }
406 rl[rlpos].lcn = prev_lcn = lcn + bmp_pos;
407 rl[rlpos].length = prev_run_len = 1;
408 rlpos++;
409 }
410 /* Done? */
411 if (!--clusters) {
412 LCN tc;
413 /*
414 * Update the current zone position. Positions
415 * of already scanned zones have been updated
416 * during the respective zone switches.
417 */
418 tc = lcn + bmp_pos + 1;
419 ntfs_debug("Done. Updating current zone "
420 "position, tc 0x%llx, "
421 "search_zone %i.",
422 (unsigned long long)tc,
423 search_zone);
424 switch (search_zone) {
425 case 1:
426 ntfs_debug("Before checks, "
427 "vol->mft_zone_pos "
428 "0x%llx.",
429 (unsigned long long)
430 vol->mft_zone_pos);
431 if (tc >= vol->mft_zone_end) {
432 vol->mft_zone_pos =
433 vol->mft_lcn;
434 if (!vol->mft_zone_end)
435 vol->mft_zone_pos = 0;
436 } else if ((bmp_initial_pos >=
437 vol->mft_zone_pos ||
438 tc > vol->mft_zone_pos)
439 && tc >= vol->mft_lcn)
440 vol->mft_zone_pos = tc;
441 ntfs_debug("After checks, "
442 "vol->mft_zone_pos "
443 "0x%llx.",
444 (unsigned long long)
445 vol->mft_zone_pos);
446 break;
447 case 2:
448 ntfs_debug("Before checks, "
449 "vol->data1_zone_pos "
450 "0x%llx.",
451 (unsigned long long)
452 vol->data1_zone_pos);
453 if (tc >= vol->nr_clusters)
454 vol->data1_zone_pos =
455 vol->mft_zone_end;
456 else if ((bmp_initial_pos >=
457 vol->data1_zone_pos ||
458 tc > vol->data1_zone_pos)
459 && tc >= vol->mft_zone_end)
460 vol->data1_zone_pos = tc;
461 ntfs_debug("After checks, "
462 "vol->data1_zone_pos "
463 "0x%llx.",
464 (unsigned long long)
465 vol->data1_zone_pos);
466 break;
467 case 4:
468 ntfs_debug("Before checks, "
469 "vol->data2_zone_pos "
470 "0x%llx.",
471 (unsigned long long)
472 vol->data2_zone_pos);
473 if (tc >= vol->mft_zone_start)
474 vol->data2_zone_pos = 0;
475 else if (bmp_initial_pos >=
476 vol->data2_zone_pos ||
477 tc > vol->data2_zone_pos)
478 vol->data2_zone_pos = tc;
479 ntfs_debug("After checks, "
480 "vol->data2_zone_pos "
481 "0x%llx.",
482 (unsigned long long)
483 vol->data2_zone_pos);
484 break;
485 default:
486 BUG();
487 }
488 ntfs_debug("Finished. Going to out.");
489 goto out;
490 }
491 lcn++;
492 }
493 bmp_pos += buf_size;
494 ntfs_debug("After inner while loop: buf_size 0x%x, lcn "
495 "0x%llx, bmp_pos 0x%llx, need_writeback %i.",
496 buf_size, (unsigned long long)lcn,
497 (unsigned long long)bmp_pos, need_writeback);
498 if (bmp_pos < zone_end) {
499 ntfs_debug("Continuing outer while loop, "
500 "bmp_pos 0x%llx, zone_end 0x%llx.",
501 (unsigned long long)bmp_pos,
502 (unsigned long long)zone_end);
503 continue;
504 }
505 zone_pass_done: /* Finished with the current zone pass. */
506 ntfs_debug("At zone_pass_done, pass %i.", pass);
507 if (pass == 1) {
508 /*
509 * Now do pass 2, scanning the first part of the zone
510 * we omitted in pass 1.
511 */
512 pass = 2;
513 zone_end = zone_start;
514 switch (search_zone) {
515 case 1: /* mft_zone */
516 zone_start = vol->mft_zone_start;
517 break;
518 case 2: /* data1_zone */
519 zone_start = vol->mft_zone_end;
520 break;
521 case 4: /* data2_zone */
522 zone_start = 0;
523 break;
524 default:
525 BUG();
526 }
527 /* Sanity check. */
528 if (zone_end < zone_start)
529 zone_end = zone_start;
530 bmp_pos = zone_start;
531 ntfs_debug("Continuing outer while loop, pass 2, "
532 "zone_start 0x%llx, zone_end 0x%llx, "
533 "bmp_pos 0x%llx.",
534 (unsigned long long)zone_start,
535 (unsigned long long)zone_end,
536 (unsigned long long)bmp_pos);
537 continue;
538 } /* pass == 2 */
539 done_zones_check:
540 ntfs_debug("At done_zones_check, search_zone %i, done_zones "
541 "before 0x%x, done_zones after 0x%x.",
542 search_zone, done_zones,
543 done_zones | search_zone);
544 done_zones |= search_zone;
545 if (done_zones < 7) {
546 ntfs_debug("Switching zone.");
547 /* Now switch to the next zone we haven't done yet. */
548 pass = 1;
549 switch (search_zone) {
550 case 1:
551 ntfs_debug("Switching from mft zone to data1 "
552 "zone.");
553 /* Update mft zone position. */
554 if (rlpos) {
555 LCN tc;
556
557 ntfs_debug("Before checks, "
558 "vol->mft_zone_pos "
559 "0x%llx.",
560 (unsigned long long)
561 vol->mft_zone_pos);
562 tc = rl[rlpos - 1].lcn +
563 rl[rlpos - 1].length;
564 if (tc >= vol->mft_zone_end) {
565 vol->mft_zone_pos =
566 vol->mft_lcn;
567 if (!vol->mft_zone_end)
568 vol->mft_zone_pos = 0;
569 } else if ((bmp_initial_pos >=
570 vol->mft_zone_pos ||
571 tc > vol->mft_zone_pos)
572 && tc >= vol->mft_lcn)
573 vol->mft_zone_pos = tc;
574 ntfs_debug("After checks, "
575 "vol->mft_zone_pos "
576 "0x%llx.",
577 (unsigned long long)
578 vol->mft_zone_pos);
579 }
580 /* Switch from mft zone to data1 zone. */
581 switch_to_data1_zone: search_zone = 2;
582 zone_start = bmp_initial_pos =
583 vol->data1_zone_pos;
584 zone_end = vol->nr_clusters;
585 if (zone_start == vol->mft_zone_end)
586 pass = 2;
587 if (zone_start >= zone_end) {
588 vol->data1_zone_pos = zone_start =
589 vol->mft_zone_end;
590 pass = 2;
591 }
592 break;
593 case 2:
594 ntfs_debug("Switching from data1 zone to "
595 "data2 zone.");
596 /* Update data1 zone position. */
597 if (rlpos) {
598 LCN tc;
599
600 ntfs_debug("Before checks, "
601 "vol->data1_zone_pos "
602 "0x%llx.",
603 (unsigned long long)
604 vol->data1_zone_pos);
605 tc = rl[rlpos - 1].lcn +
606 rl[rlpos - 1].length;
607 if (tc >= vol->nr_clusters)
608 vol->data1_zone_pos =
609 vol->mft_zone_end;
610 else if ((bmp_initial_pos >=
611 vol->data1_zone_pos ||
612 tc > vol->data1_zone_pos)
613 && tc >= vol->mft_zone_end)
614 vol->data1_zone_pos = tc;
615 ntfs_debug("After checks, "
616 "vol->data1_zone_pos "
617 "0x%llx.",
618 (unsigned long long)
619 vol->data1_zone_pos);
620 }
621 /* Switch from data1 zone to data2 zone. */
622 search_zone = 4;
623 zone_start = bmp_initial_pos =
624 vol->data2_zone_pos;
625 zone_end = vol->mft_zone_start;
626 if (!zone_start)
627 pass = 2;
628 if (zone_start >= zone_end) {
629 vol->data2_zone_pos = zone_start =
630 bmp_initial_pos = 0;
631 pass = 2;
632 }
633 break;
634 case 4:
635 ntfs_debug("Switching from data2 zone to "
636 "data1 zone.");
637 /* Update data2 zone position. */
638 if (rlpos) {
639 LCN tc;
640
641 ntfs_debug("Before checks, "
642 "vol->data2_zone_pos "
643 "0x%llx.",
644 (unsigned long long)
645 vol->data2_zone_pos);
646 tc = rl[rlpos - 1].lcn +
647 rl[rlpos - 1].length;
648 if (tc >= vol->mft_zone_start)
649 vol->data2_zone_pos = 0;
650 else if (bmp_initial_pos >=
651 vol->data2_zone_pos ||
652 tc > vol->data2_zone_pos)
653 vol->data2_zone_pos = tc;
654 ntfs_debug("After checks, "
655 "vol->data2_zone_pos "
656 "0x%llx.",
657 (unsigned long long)
658 vol->data2_zone_pos);
659 }
660 /* Switch from data2 zone to data1 zone. */
661 goto switch_to_data1_zone;
662 default:
663 BUG();
664 }
665 ntfs_debug("After zone switch, search_zone %i, "
666 "pass %i, bmp_initial_pos 0x%llx, "
667 "zone_start 0x%llx, zone_end 0x%llx.",
668 search_zone, pass,
669 (unsigned long long)bmp_initial_pos,
670 (unsigned long long)zone_start,
671 (unsigned long long)zone_end);
672 bmp_pos = zone_start;
673 if (zone_start == zone_end) {
674 ntfs_debug("Empty zone, going to "
675 "done_zones_check.");
676 /* Empty zone. Don't bother searching it. */
677 goto done_zones_check;
678 }
679 ntfs_debug("Continuing outer while loop.");
680 continue;
681 } /* done_zones == 7 */
682 ntfs_debug("All zones are finished.");
683 /*
684 * All zones are finished! If DATA_ZONE, shrink mft zone. If
685 * MFT_ZONE, we have really run out of space.
686 */
687 mft_zone_size = vol->mft_zone_end - vol->mft_zone_start;
688 ntfs_debug("vol->mft_zone_start 0x%llx, vol->mft_zone_end "
689 "0x%llx, mft_zone_size 0x%llx.",
690 (unsigned long long)vol->mft_zone_start,
691 (unsigned long long)vol->mft_zone_end,
692 (unsigned long long)mft_zone_size);
693 if (zone == MFT_ZONE || mft_zone_size <= 0) {
694 ntfs_debug("No free clusters left, going to out.");
695 /* Really no more space left on device. */
696 err = -ENOSPC;
697 goto out;
698 } /* zone == DATA_ZONE && mft_zone_size > 0 */
699 ntfs_debug("Shrinking mft zone.");
700 zone_end = vol->mft_zone_end;
701 mft_zone_size >>= 1;
702 if (mft_zone_size > 0)
703 vol->mft_zone_end = vol->mft_zone_start + mft_zone_size;
704 else /* mft zone and data2 zone no longer exist. */
705 vol->data2_zone_pos = vol->mft_zone_start =
706 vol->mft_zone_end = 0;
707 if (vol->mft_zone_pos >= vol->mft_zone_end) {
708 vol->mft_zone_pos = vol->mft_lcn;
709 if (!vol->mft_zone_end)
710 vol->mft_zone_pos = 0;
711 }
712 bmp_pos = zone_start = bmp_initial_pos =
713 vol->data1_zone_pos = vol->mft_zone_end;
714 search_zone = 2;
715 pass = 2;
716 done_zones &= ~2;
717 ntfs_debug("After shrinking mft zone, mft_zone_size 0x%llx, "
718 "vol->mft_zone_start 0x%llx, "
719 "vol->mft_zone_end 0x%llx, "
720 "vol->mft_zone_pos 0x%llx, search_zone 2, "
721 "pass 2, dones_zones 0x%x, zone_start 0x%llx, "
722 "zone_end 0x%llx, vol->data1_zone_pos 0x%llx, "
723 "continuing outer while loop.",
724 (unsigned long long)mft_zone_size,
725 (unsigned long long)vol->mft_zone_start,
726 (unsigned long long)vol->mft_zone_end,
727 (unsigned long long)vol->mft_zone_pos,
728 done_zones, (unsigned long long)zone_start,
729 (unsigned long long)zone_end,
730 (unsigned long long)vol->data1_zone_pos);
731 }
732 ntfs_debug("After outer while loop.");
733 out:
734 ntfs_debug("At out.");
735 /* Add runlist terminator element. */
736 if (likely(rl)) {
737 rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
738 rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
739 rl[rlpos].length = 0;
740 }
741 if (likely(page && !IS_ERR(page))) {
742 if (need_writeback) {
743 ntfs_debug("Marking page dirty.");
744 flush_dcache_page(page);
745 set_page_dirty(page);
746 need_writeback = 0;
747 }
748 ntfs_unmap_page(page);
749 }
750 if (likely(!err)) {
751 up_write(&vol->lcnbmp_lock);
752 ntfs_debug("Done.");
753 return rl;
754 }
755 ntfs_error(vol->sb, "Failed to allocate clusters, aborting "
756 "(error %i).", err);
757 if (rl) {
758 int err2;
759
760 if (err == -ENOSPC)
761 ntfs_debug("Not enough space to complete allocation, "
762 "err -ENOSPC, first free lcn 0x%llx, "
763 "could allocate up to 0x%llx "
764 "clusters.",
765 (unsigned long long)rl[0].lcn,
766 (unsigned long long)(count - clusters));
767 /* Deallocate all allocated clusters. */
768 ntfs_debug("Attempting rollback...");
769 err2 = ntfs_cluster_free_from_rl_nolock(vol, rl);
770 if (err2) {
771 ntfs_error(vol->sb, "Failed to rollback (error %i). "
772 "Leaving inconsistent metadata! "
773 "Unmount and run chkdsk.", err2);
774 NVolSetErrors(vol);
775 }
776 /* Free the runlist. */
777 ntfs_free(rl);
778 } else if (err == -ENOSPC)
779 ntfs_debug("No space left at all, err = -ENOSPC, first free "
780 "lcn = 0x%llx.",
781 (long long)vol->data1_zone_pos);
782 up_write(&vol->lcnbmp_lock);
783 return ERR_PTR(err);
784 }
785
786 /**
787 * __ntfs_cluster_free - free clusters on an ntfs volume
788 * @vi: vfs inode whose runlist describes the clusters to free
789 * @start_vcn: vcn in the runlist of @vi at which to start freeing clusters
790 * @count: number of clusters to free or -1 for all clusters
791 * @is_rollback: if TRUE this is a rollback operation
792 *
793 * Free @count clusters starting at the cluster @start_vcn in the runlist
794 * described by the vfs inode @vi.
795 *
796 * If @count is -1, all clusters from @start_vcn to the end of the runlist are
797 * deallocated. Thus, to completely free all clusters in a runlist, use
798 * @start_vcn = 0 and @count = -1.
799 *
800 * @is_rollback should always be FALSE, it is for internal use to rollback
801 * errors. You probably want to use ntfs_cluster_free() instead.
802 *
803 * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
804 * has to deal with it later.
805 *
806 * Return the number of deallocated clusters (not counting sparse ones) on
807 * success and -errno on error.
808 *
809 * Locking: - The runlist described by @vi must be unlocked on entry and is
810 * unlocked on return.
811 * - This function takes the runlist lock of @vi for reading and
812 * sometimes for writing and sometimes modifies the runlist.
813 * - The volume lcn bitmap must be unlocked on entry and is unlocked
814 * on return.
815 * - This function takes the volume lcn bitmap lock for writing and
816 * modifies the bitmap contents.
817 */
818 s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
819 const BOOL is_rollback)
820 {
821 s64 delta, to_free, total_freed, real_freed;
822 ntfs_inode *ni;
823 ntfs_volume *vol;
824 struct inode *lcnbmp_vi;
825 runlist_element *rl;
826 int err;
827
828 BUG_ON(!vi);
829 ntfs_debug("Entering for i_ino 0x%lx, start_vcn 0x%llx, count "
830 "0x%llx.%s", vi->i_ino, (unsigned long long)start_vcn,
831 (unsigned long long)count,
832 is_rollback ? " (rollback)" : "");
833 ni = NTFS_I(vi);
834 vol = ni->vol;
835 lcnbmp_vi = vol->lcnbmp_ino;
836 BUG_ON(!lcnbmp_vi);
837 BUG_ON(start_vcn < 0);
838 BUG_ON(count < -1);
839 /*
840 * Lock the lcn bitmap for writing but only if not rolling back. We
841 * must hold the lock all the way including through rollback otherwise
842 * rollback is not possible because once we have cleared a bit and
843 * dropped the lock, anyone could have set the bit again, thus
844 * allocating the cluster for another use.
845 */
846 if (likely(!is_rollback))
847 down_write(&vol->lcnbmp_lock);
848
849 total_freed = real_freed = 0;
850
851 down_read(&ni->runlist.lock);
852 rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, FALSE);
853 if (IS_ERR(rl)) {
854 if (!is_rollback)
855 ntfs_error(vol->sb, "Failed to find first runlist "
856 "element (error %li), aborting.",
857 PTR_ERR(rl));
858 err = PTR_ERR(rl);
859 goto err_out;
860 }
861 if (unlikely(rl->lcn < LCN_HOLE)) {
862 if (!is_rollback)
863 ntfs_error(vol->sb, "First runlist element has "
864 "invalid lcn, aborting.");
865 err = -EIO;
866 goto err_out;
867 }
868 /* Find the starting cluster inside the run that needs freeing. */
869 delta = start_vcn - rl->vcn;
870
871 /* The number of clusters in this run that need freeing. */
872 to_free = rl->length - delta;
873 if (count >= 0 && to_free > count)
874 to_free = count;
875
876 if (likely(rl->lcn >= 0)) {
877 /* Do the actual freeing of the clusters in this run. */
878 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn + delta,
879 to_free, likely(!is_rollback) ? 0 : 1);
880 if (unlikely(err)) {
881 if (!is_rollback)
882 ntfs_error(vol->sb, "Failed to clear first run "
883 "(error %i), aborting.", err);
884 goto err_out;
885 }
886 /* We have freed @to_free real clusters. */
887 real_freed = to_free;
888 };
889 /* Go to the next run and adjust the number of clusters left to free. */
890 ++rl;
891 if (count >= 0)
892 count -= to_free;
893
894 /* Keep track of the total "freed" clusters, including sparse ones. */
895 total_freed = to_free;
896 /*
897 * Loop over the remaining runs, using @count as a capping value, and
898 * free them.
899 */
900 for (; rl->length && count != 0; ++rl) {
901 if (unlikely(rl->lcn < LCN_HOLE)) {
902 VCN vcn;
903
904 /* Attempt to map runlist. */
905 vcn = rl->vcn;
906 rl = ntfs_attr_find_vcn_nolock(ni, vcn, FALSE);
907 if (IS_ERR(rl)) {
908 err = PTR_ERR(rl);
909 if (!is_rollback)
910 ntfs_error(vol->sb, "Failed to map "
911 "runlist fragment or "
912 "failed to find "
913 "subsequent runlist "
914 "element.");
915 goto err_out;
916 }
917 if (unlikely(rl->lcn < LCN_HOLE)) {
918 if (!is_rollback)
919 ntfs_error(vol->sb, "Runlist element "
920 "has invalid lcn "
921 "(0x%llx).",
922 (unsigned long long)
923 rl->lcn);
924 err = -EIO;
925 goto err_out;
926 }
927 }
928 /* The number of clusters in this run that need freeing. */
929 to_free = rl->length;
930 if (count >= 0 && to_free > count)
931 to_free = count;
932
933 if (likely(rl->lcn >= 0)) {
934 /* Do the actual freeing of the clusters in the run. */
935 err = ntfs_bitmap_set_bits_in_run(lcnbmp_vi, rl->lcn,
936 to_free, likely(!is_rollback) ? 0 : 1);
937 if (unlikely(err)) {
938 if (!is_rollback)
939 ntfs_error(vol->sb, "Failed to clear "
940 "subsequent run.");
941 goto err_out;
942 }
943 /* We have freed @to_free real clusters. */
944 real_freed += to_free;
945 }
946 /* Adjust the number of clusters left to free. */
947 if (count >= 0)
948 count -= to_free;
949
950 /* Update the total done clusters. */
951 total_freed += to_free;
952 }
953 up_read(&ni->runlist.lock);
954 if (likely(!is_rollback))
955 up_write(&vol->lcnbmp_lock);
956
957 BUG_ON(count > 0);
958
959 /* We are done. Return the number of actually freed clusters. */
960 ntfs_debug("Done.");
961 return real_freed;
962 err_out:
963 up_read(&ni->runlist.lock);
964 if (is_rollback)
965 return err;
966 /* If no real clusters were freed, no need to rollback. */
967 if (!real_freed) {
968 up_write(&vol->lcnbmp_lock);
969 return err;
970 }
971 /*
972 * Attempt to rollback and if that succeeds just return the error code.
973 * If rollback fails, set the volume errors flag, emit an error
974 * message, and return the error code.
975 */
976 delta = __ntfs_cluster_free(vi, start_vcn, total_freed, TRUE);
977 if (delta < 0) {
978 ntfs_error(vol->sb, "Failed to rollback (error %i). Leaving "
979 "inconsistent metadata! Unmount and run "
980 "chkdsk.", (int)delta);
981 NVolSetErrors(vol);
982 }
983 up_write(&vol->lcnbmp_lock);
984 ntfs_error(vol->sb, "Aborting (error %i).", err);
985 return err;
986 }
987
988 #endif /* NTFS_RW */
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree