2 * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
4 * Copyright (c) 2001-2005 Anton Altaparmakov
5 * Copyright (c) 2002-2005 Richard Russon
7 * This program/include file is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as published
9 * by the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program/include file is distributed in the hope that it will be
13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program (in the main directory of the Linux-NTFS
19 * distribution in the file COPYING); if not, write to the Free Software
20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
30 * ntfs_rl_mm - runlist memmove
32 * It is up to the caller to serialize access to the runlist @base.
34 static inline void ntfs_rl_mm(runlist_element *base, int dst, int src,
37 if (likely((dst != src) && (size > 0)))
38 memmove(base + dst, base + src, size * sizeof(*base));
42 * ntfs_rl_mc - runlist memory copy
44 * It is up to the caller to serialize access to the runlists @dstbase and
47 static inline void ntfs_rl_mc(runlist_element *dstbase, int dst,
48 runlist_element *srcbase, int src, int size)
51 memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase));
55 * ntfs_rl_realloc - Reallocate memory for runlists
56 * @rl: original runlist
57 * @old_size: number of runlist elements in the original runlist @rl
58 * @new_size: number of runlist elements we need space for
60 * As the runlists grow, more memory will be required. To prevent the
61 * kernel having to allocate and reallocate large numbers of small bits of
62 * memory, this function returns an entire page of memory.
64 * It is up to the caller to serialize access to the runlist @rl.
66 * N.B. If the new allocation doesn't require a different number of pages in
67 * memory, the function will return the original pointer.
69 * On success, return a pointer to the newly allocated, or recycled, memory.
70 * On error, return -errno. The following error codes are defined:
71 * -ENOMEM - Not enough memory to allocate runlist array.
72 * -EINVAL - Invalid parameters were passed in.
74 static inline runlist_element *ntfs_rl_realloc(runlist_element *rl,
75 int old_size, int new_size)
77 runlist_element *new_rl;
79 old_size = PAGE_ALIGN(old_size * sizeof(*rl));
80 new_size = PAGE_ALIGN(new_size * sizeof(*rl));
81 if (old_size == new_size)
84 new_rl = ntfs_malloc_nofs(new_size);
85 if (unlikely(!new_rl))
86 return ERR_PTR(-ENOMEM);
88 if (likely(rl != NULL)) {
89 if (unlikely(old_size > new_size))
91 memcpy(new_rl, rl, old_size);
98 * ntfs_rl_realloc_nofail - Reallocate memory for runlists
99 * @rl: original runlist
100 * @old_size: number of runlist elements in the original runlist @rl
101 * @new_size: number of runlist elements we need space for
103 * As the runlists grow, more memory will be required. To prevent the
104 * kernel having to allocate and reallocate large numbers of small bits of
105 * memory, this function returns an entire page of memory.
107 * This function guarantees that the allocation will succeed. It will sleep
108 * for as long as it takes to complete the allocation.
110 * It is up to the caller to serialize access to the runlist @rl.
112 * N.B. If the new allocation doesn't require a different number of pages in
113 * memory, the function will return the original pointer.
115 * On success, return a pointer to the newly allocated, or recycled, memory.
116 * On error, return -errno. The following error codes are defined:
117 * -ENOMEM - Not enough memory to allocate runlist array.
118 * -EINVAL - Invalid parameters were passed in.
120 static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl,
121 int old_size, int new_size)
123 runlist_element *new_rl;
125 old_size = PAGE_ALIGN(old_size * sizeof(*rl));
126 new_size = PAGE_ALIGN(new_size * sizeof(*rl));
127 if (old_size == new_size)
130 new_rl = ntfs_malloc_nofs_nofail(new_size);
133 if (likely(rl != NULL)) {
134 if (unlikely(old_size > new_size))
136 memcpy(new_rl, rl, old_size);
143 * ntfs_are_rl_mergeable - test if two runlists can be joined together
144 * @dst: original runlist
145 * @src: new runlist to test for mergeability with @dst
147 * Test if two runlists can be joined together. For this, their VCNs and LCNs
150 * It is up to the caller to serialize access to the runlists @dst and @src.
152 * Return: TRUE Success, the runlists can be merged.
153 * FALSE Failure, the runlists cannot be merged.
155 static inline BOOL ntfs_are_rl_mergeable(runlist_element *dst,
156 runlist_element *src)
161 if ((dst->lcn < 0) || (src->lcn < 0)) { /* Are we merging holes? */
162 if (dst->lcn == LCN_HOLE && src->lcn == LCN_HOLE)
166 if ((dst->lcn + dst->length) != src->lcn) /* Are the runs contiguous? */
168 if ((dst->vcn + dst->length) != src->vcn) /* Are the runs misaligned? */
175 * __ntfs_rl_merge - merge two runlists without testing if they can be merged
176 * @dst: original, destination runlist
177 * @src: new runlist to merge with @dst
179 * Merge the two runlists, writing into the destination runlist @dst. The
180 * caller must make sure the runlists can be merged or this will corrupt the
181 * destination runlist.
183 * It is up to the caller to serialize access to the runlists @dst and @src.
185 static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src)
187 dst->length += src->length;
191 * ntfs_rl_append - append a runlist after a given element
192 * @dst: original runlist to be worked on
193 * @dsize: number of elements in @dst (including end marker)
194 * @src: runlist to be inserted into @dst
195 * @ssize: number of elements in @src (excluding end marker)
196 * @loc: append the new runlist @src after this element in @dst
198 * Append the runlist @src after element @loc in @dst. Merge the right end of
199 * the new runlist, if necessary. Adjust the size of the hole before the
202 * It is up to the caller to serialize access to the runlists @dst and @src.
204 * On success, return a pointer to the new, combined, runlist. Note, both
205 * runlists @dst and @src are deallocated before returning so you cannot use
206 * the pointers for anything any more. (Strictly speaking the returned runlist
207 * may be the same as @dst but this is irrelevant.)
209 * On error, return -errno. Both runlists are left unmodified. The following
210 * error codes are defined:
211 * -ENOMEM - Not enough memory to allocate runlist array.
212 * -EINVAL - Invalid parameters were passed in.
214 static inline runlist_element *ntfs_rl_append(runlist_element *dst,
215 int dsize, runlist_element *src, int ssize, int loc)
217 BOOL right; /* Right end of @src needs merging. */
218 int marker; /* End of the inserted runs. */
223 /* First, check if the right hand end needs merging. */
224 right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
226 /* Space required: @dst size + @src size, less one if we merged. */
227 dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right);
231 * We are guaranteed to succeed from here so can start modifying the
235 /* First, merge the right hand end, if necessary. */
237 __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
239 /* First run after the @src runs that have been inserted. */
240 marker = loc + ssize + 1;
242 /* Move the tail of @dst out of the way, then copy in @src. */
243 ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right));
244 ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
246 /* Adjust the size of the preceding hole. */
247 dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
249 /* We may have changed the length of the file, so fix the end marker */
250 if (dst[marker].lcn == LCN_ENOENT)
251 dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
257 * ntfs_rl_insert - insert a runlist into another
258 * @dst: original runlist to be worked on
259 * @dsize: number of elements in @dst (including end marker)
260 * @src: new runlist to be inserted
261 * @ssize: number of elements in @src (excluding end marker)
262 * @loc: insert the new runlist @src before this element in @dst
264 * Insert the runlist @src before element @loc in the runlist @dst. Merge the
265 * left end of the new runlist, if necessary. Adjust the size of the hole
266 * after the inserted runlist.
268 * It is up to the caller to serialize access to the runlists @dst and @src.
270 * On success, return a pointer to the new, combined, runlist. Note, both
271 * runlists @dst and @src are deallocated before returning so you cannot use
272 * the pointers for anything any more. (Strictly speaking the returned runlist
273 * may be the same as @dst but this is irrelevant.)
275 * On error, return -errno. Both runlists are left unmodified. The following
276 * error codes are defined:
277 * -ENOMEM - Not enough memory to allocate runlist array.
278 * -EINVAL - Invalid parameters were passed in.
280 static inline runlist_element *ntfs_rl_insert(runlist_element *dst,
281 int dsize, runlist_element *src, int ssize, int loc)
283 BOOL left = FALSE; /* Left end of @src needs merging. */
284 BOOL disc = FALSE; /* Discontinuity between @dst and @src. */
285 int marker; /* End of the inserted runs. */
291 * disc => Discontinuity between the end of @dst and the start of @src.
292 * This means we might need to insert a "not mapped" run.
295 disc = (src[0].vcn > 0);
299 left = ntfs_are_rl_mergeable(dst + loc - 1, src);
301 merged_length = dst[loc - 1].length;
303 merged_length += src->length;
305 disc = (src[0].vcn > dst[loc - 1].vcn + merged_length);
308 * Space required: @dst size + @src size, less one if we merged, plus
309 * one if there was a discontinuity.
311 dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc);
315 * We are guaranteed to succeed from here so can start modifying the
319 __ntfs_rl_merge(dst + loc - 1, src);
321 * First run after the @src runs that have been inserted.
322 * Nominally, @marker equals @loc + @ssize, i.e. location + number of
323 * runs in @src. However, if @left, then the first run in @src has
324 * been merged with one in @dst. And if @disc, then @dst and @src do
325 * not meet and we need an extra run to fill the gap.
327 marker = loc + ssize - left + disc;
329 /* Move the tail of @dst out of the way, then copy in @src. */
330 ntfs_rl_mm(dst, marker, loc, dsize - loc);
331 ntfs_rl_mc(dst, loc + disc, src, left, ssize - left);
333 /* Adjust the VCN of the first run after the insertion... */
334 dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
335 /* ... and the length. */
336 if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED)
337 dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn;
339 /* Writing beyond the end of the file and there is a discontinuity. */
342 dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length;
343 dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn;
346 dst[loc].length = dst[loc + 1].vcn;
348 dst[loc].lcn = LCN_RL_NOT_MAPPED;
354 * ntfs_rl_replace - overwrite a runlist element with another runlist
355 * @dst: original runlist to be worked on
356 * @dsize: number of elements in @dst (including end marker)
357 * @src: new runlist to be inserted
358 * @ssize: number of elements in @src (excluding end marker)
359 * @loc: index in runlist @dst to overwrite with @src
361 * Replace the runlist element @dst at @loc with @src. Merge the left and
362 * right ends of the inserted runlist, if necessary.
364 * It is up to the caller to serialize access to the runlists @dst and @src.
366 * On success, return a pointer to the new, combined, runlist. Note, both
367 * runlists @dst and @src are deallocated before returning so you cannot use
368 * the pointers for anything any more. (Strictly speaking the returned runlist
369 * may be the same as @dst but this is irrelevant.)
371 * On error, return -errno. Both runlists are left unmodified. The following
372 * error codes are defined:
373 * -ENOMEM - Not enough memory to allocate runlist array.
374 * -EINVAL - Invalid parameters were passed in.
376 static inline runlist_element *ntfs_rl_replace(runlist_element *dst,
377 int dsize, runlist_element *src, int ssize, int loc)
379 BOOL left = FALSE; /* Left end of @src needs merging. */
380 BOOL right; /* Right end of @src needs merging. */
381 int tail; /* Start of tail of @dst. */
382 int marker; /* End of the inserted runs. */
387 /* First, merge the left and right ends, if necessary. */
388 right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1);
390 left = ntfs_are_rl_mergeable(dst + loc - 1, src);
392 * Allocate some space. We will need less if the left, right, or both
395 dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right);
399 * We are guaranteed to succeed from here so can start modifying the
403 __ntfs_rl_merge(src + ssize - 1, dst + loc + 1);
405 __ntfs_rl_merge(dst + loc - 1, src);
407 * First run of @dst that needs to be moved out of the way to make
408 * space for the runs to be copied from @src, i.e. the first run of the
411 tail = loc + right + 1;
413 * First run after the @src runs that have been inserted, i.e. where
414 * the tail of @dst needs to be moved to.
415 * Nominally, marker equals @loc + @ssize, i.e. location + number of
416 * runs in @src). However, if @left, then the first run in @src has
417 * been merged with one in @dst.
419 marker = loc + ssize - left;
421 /* Move the tail of @dst out of the way, then copy in @src. */
422 ntfs_rl_mm(dst, marker, tail, dsize - tail);
423 ntfs_rl_mc(dst, loc, src, left, ssize - left);
425 /* We may have changed the length of the file, so fix the end marker. */
426 if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT)
427 dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length;
432 * ntfs_rl_split - insert a runlist into the centre of a hole
433 * @dst: original runlist to be worked on
434 * @dsize: number of elements in @dst (including end marker)
435 * @src: new runlist to be inserted
436 * @ssize: number of elements in @src (excluding end marker)
437 * @loc: index in runlist @dst at which to split and insert @src
439 * Split the runlist @dst at @loc into two and insert @new in between the two
440 * fragments. No merging of runlists is necessary. Adjust the size of the
443 * It is up to the caller to serialize access to the runlists @dst and @src.
445 * On success, return a pointer to the new, combined, runlist. Note, both
446 * runlists @dst and @src are deallocated before returning so you cannot use
447 * the pointers for anything any more. (Strictly speaking the returned runlist
448 * may be the same as @dst but this is irrelevant.)
450 * On error, return -errno. Both runlists are left unmodified. The following
451 * error codes are defined:
452 * -ENOMEM - Not enough memory to allocate runlist array.
453 * -EINVAL - Invalid parameters were passed in.
455 static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize,
456 runlist_element *src, int ssize, int loc)
461 /* Space required: @dst size + @src size + one new hole. */
462 dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1);
466 * We are guaranteed to succeed from here so can start modifying the
470 /* Move the tail of @dst out of the way, then copy in @src. */
471 ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc);
472 ntfs_rl_mc(dst, loc + 1, src, 0, ssize);
474 /* Adjust the size of the holes either size of @src. */
475 dst[loc].length = dst[loc+1].vcn - dst[loc].vcn;
476 dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length;
477 dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn;
483 * ntfs_runlists_merge - merge two runlists into one
484 * @drl: original runlist to be worked on
485 * @srl: new runlist to be merged into @drl
487 * First we sanity check the two runlists @srl and @drl to make sure that they
488 * are sensible and can be merged. The runlist @srl must be either after the
489 * runlist @drl or completely within a hole (or unmapped region) in @drl.
491 * It is up to the caller to serialize access to the runlists @drl and @srl.
493 * Merging of runlists is necessary in two cases:
494 * 1. When attribute lists are used and a further extent is being mapped.
495 * 2. When new clusters are allocated to fill a hole or extend a file.
497 * There are four possible ways @srl can be merged. It can:
498 * - be inserted at the beginning of a hole,
499 * - split the hole in two and be inserted between the two fragments,
500 * - be appended at the end of a hole, or it can
501 * - replace the whole hole.
502 * It can also be appended to the end of the runlist, which is just a variant
503 * of the insert case.
505 * On success, return a pointer to the new, combined, runlist. Note, both
506 * runlists @drl and @srl are deallocated before returning so you cannot use
507 * the pointers for anything any more. (Strictly speaking the returned runlist
508 * may be the same as @dst but this is irrelevant.)
510 * On error, return -errno. Both runlists are left unmodified. The following
511 * error codes are defined:
512 * -ENOMEM - Not enough memory to allocate runlist array.
513 * -EINVAL - Invalid parameters were passed in.
514 * -ERANGE - The runlists overlap and cannot be merged.
516 runlist_element *ntfs_runlists_merge(runlist_element *drl,
517 runlist_element *srl)
519 int di, si; /* Current index into @[ds]rl. */
520 int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */
521 int dins; /* Index into @drl at which to insert @srl. */
522 int dend, send; /* Last index into @[ds]rl. */
523 int dfinal, sfinal; /* The last index into @[ds]rl with
530 ntfs_debug_dump_runlist(drl);
532 ntfs_debug_dump_runlist(srl);
535 /* Check for silly calling... */
538 if (IS_ERR(srl) || IS_ERR(drl))
539 return ERR_PTR(-EINVAL);
541 /* Check for the case where the first mapping is being done now. */
542 if (unlikely(!drl)) {
544 /* Complete the source runlist if necessary. */
545 if (unlikely(drl[0].vcn)) {
546 /* Scan to the end of the source runlist. */
547 for (dend = 0; likely(drl[dend].length); dend++)
550 drl = ntfs_rl_realloc(drl, dend, dend + 1);
553 /* Insert start element at the front of the runlist. */
554 ntfs_rl_mm(drl, 1, 0, dend);
556 drl[0].lcn = LCN_RL_NOT_MAPPED;
557 drl[0].length = drl[1].vcn;
564 /* Skip any unmapped start element(s) in the source runlist. */
565 while (srl[si].length && srl[si].lcn < LCN_HOLE)
568 /* Can't have an entirely unmapped source runlist. */
569 BUG_ON(!srl[si].length);
571 /* Record the starting points. */
575 * Skip forward in @drl until we reach the position where @srl needs to
576 * be inserted. If we reach the end of @drl, @srl just needs to be
579 for (; drl[di].length; di++) {
580 if (drl[di].vcn + drl[di].length > srl[sstart].vcn)
585 /* Sanity check for illegal overlaps. */
586 if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) &&
587 (srl[si].lcn >= 0)) {
588 ntfs_error(NULL, "Run lists overlap. Cannot merge!");
589 return ERR_PTR(-ERANGE);
592 /* Scan to the end of both runlists in order to know their sizes. */
593 for (send = si; srl[send].length; send++)
595 for (dend = di; drl[dend].length; dend++)
598 if (srl[send].lcn == LCN_ENOENT)
599 marker_vcn = srl[marker = send].vcn;
601 /* Scan to the last element with lcn >= LCN_HOLE. */
602 for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--)
604 for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--)
610 int ds = dend + 1; /* Number of elements in drl & srl */
611 int ss = sfinal - sstart + 1;
613 start = ((drl[dins].lcn < LCN_RL_NOT_MAPPED) || /* End of file */
614 (drl[dins].vcn == srl[sstart].vcn)); /* Start of hole */
615 finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) && /* End of file */
616 ((drl[dins].vcn + drl[dins].length) <= /* End of hole */
617 (srl[send - 1].vcn + srl[send - 1].length)));
619 /* Or we will lose an end marker. */
620 if (finish && !drl[dins].length)
622 if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn))
625 ntfs_debug("dfinal = %i, dend = %i", dfinal, dend);
626 ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart, sfinal, send);
627 ntfs_debug("start = %i, finish = %i", start, finish);
628 ntfs_debug("ds = %i, ss = %i, dins = %i", ds, ss, dins);
632 drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins);
634 drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins);
637 drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins);
639 drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins);
642 ntfs_error(NULL, "Merge failed.");
647 ntfs_debug("Triggering marker code.");
648 for (ds = dend; drl[ds].length; ds++)
650 /* We only need to care if @srl ended after @drl. */
651 if (drl[ds].vcn <= marker_vcn) {
654 if (drl[ds].vcn == marker_vcn) {
655 ntfs_debug("Old marker = 0x%llx, replacing "
659 drl[ds].lcn = LCN_ENOENT;
663 * We need to create an unmapped runlist element in
664 * @drl or extend an existing one before adding the
667 if (drl[ds].lcn == LCN_ENOENT) {
671 if (drl[ds].lcn != LCN_RL_NOT_MAPPED) {
672 /* Add an unmapped runlist element. */
674 drl = ntfs_rl_realloc_nofail(drl, ds,
679 /* Need to set vcn if it isn't set already. */
681 drl[ds].vcn = drl[ds - 1].vcn +
683 drl[ds].lcn = LCN_RL_NOT_MAPPED;
684 /* We now used up a slot. */
687 drl[ds].length = marker_vcn - drl[ds].vcn;
688 /* Finally add the ENOENT terminator. */
691 drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1);
692 drl[ds].vcn = marker_vcn;
693 drl[ds].lcn = LCN_ENOENT;
694 drl[ds].length = (s64)0;
700 /* The merge was completed successfully. */
701 ntfs_debug("Merged runlist:");
702 ntfs_debug_dump_runlist(drl);
707 * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
708 * @vol: ntfs volume on which the attribute resides
709 * @attr: attribute record whose mapping pairs array to decompress
710 * @old_rl: optional runlist in which to insert @attr's runlist
712 * It is up to the caller to serialize access to the runlist @old_rl.
714 * Decompress the attribute @attr's mapping pairs array into a runlist. On
715 * success, return the decompressed runlist.
717 * If @old_rl is not NULL, decompressed runlist is inserted into the
718 * appropriate place in @old_rl and the resultant, combined runlist is
719 * returned. The original @old_rl is deallocated.
721 * On error, return -errno. @old_rl is left unmodified in that case.
723 * The following error codes are defined:
724 * -ENOMEM - Not enough memory to allocate runlist array.
725 * -EIO - Corrupt runlist.
726 * -EINVAL - Invalid parameters were passed in.
727 * -ERANGE - The two runlists overlap.
729 * FIXME: For now we take the conceptionally simplest approach of creating the
730 * new runlist disregarding the already existing one and then splicing the
731 * two into one, if that is possible (we check for overlap and discard the new
732 * runlist if overlap present before returning ERR_PTR(-ERANGE)).
734 runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
735 const ATTR_RECORD *attr, runlist_element *old_rl)
737 VCN vcn; /* Current vcn. */
738 LCN lcn; /* Current lcn. */
739 s64 deltaxcn; /* Change in [vl]cn. */
740 runlist_element *rl; /* The output runlist. */
741 u8 *buf; /* Current position in mapping pairs array. */
742 u8 *attr_end; /* End of attribute. */
743 int rlsize; /* Size of runlist buffer. */
744 u16 rlpos; /* Current runlist position in units of
746 u8 b; /* Current byte offset in buf. */
749 /* Make sure attr exists and is non-resident. */
750 if (!attr || !attr->non_resident || sle64_to_cpu(
751 attr->data.non_resident.lowest_vcn) < (VCN)0) {
752 ntfs_error(vol->sb, "Invalid arguments.");
753 return ERR_PTR(-EINVAL);
756 /* Start at vcn = lowest_vcn and lcn 0. */
757 vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn);
759 /* Get start of the mapping pairs array. */
760 buf = (u8*)attr + le16_to_cpu(
761 attr->data.non_resident.mapping_pairs_offset);
762 attr_end = (u8*)attr + le32_to_cpu(attr->length);
763 if (unlikely(buf < (u8*)attr || buf > attr_end)) {
764 ntfs_error(vol->sb, "Corrupt attribute.");
765 return ERR_PTR(-EIO);
767 /* If the mapping pairs array is valid but empty, nothing to do. */
770 /* Current position in runlist array. */
772 /* Allocate first page and set current runlist size to one page. */
773 rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE);
775 return ERR_PTR(-ENOMEM);
776 /* Insert unmapped starting element if necessary. */
779 rl->lcn = LCN_RL_NOT_MAPPED;
783 while (buf < attr_end && *buf) {
785 * Allocate more memory if needed, including space for the
786 * not-mapped and terminator elements. ntfs_malloc_nofs()
787 * operates on whole pages only.
789 if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) {
790 runlist_element *rl2;
792 rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE);
793 if (unlikely(!rl2)) {
795 return ERR_PTR(-ENOMEM);
797 memcpy(rl2, rl, rlsize);
802 /* Enter the current vcn into the current runlist element. */
805 * Get the change in vcn, i.e. the run length in clusters.
806 * Doing it this way ensures that we signextend negative values.
807 * A negative run length doesn't make any sense, but hey, I
808 * didn't make up the NTFS specs and Windows NT4 treats the run
809 * length as a signed value so that's how it is...
813 if (unlikely(buf + b > attr_end))
815 for (deltaxcn = (s8)buf[b--]; b; b--)
816 deltaxcn = (deltaxcn << 8) + buf[b];
817 } else { /* The length entry is compulsory. */
818 ntfs_error(vol->sb, "Missing length entry in mapping "
823 * Assume a negative length to indicate data corruption and
824 * hence clean-up and return NULL.
826 if (unlikely(deltaxcn < 0)) {
827 ntfs_error(vol->sb, "Invalid length in mapping pairs "
832 * Enter the current run length into the current runlist
835 rl[rlpos].length = deltaxcn;
836 /* Increment the current vcn by the current run length. */
839 * There might be no lcn change at all, as is the case for
840 * sparse clusters on NTFS 3.0+, in which case we set the lcn
844 rl[rlpos].lcn = LCN_HOLE;
846 /* Get the lcn change which really can be negative. */
848 b = b2 + ((*buf >> 4) & 0xf);
849 if (buf + b > attr_end)
851 for (deltaxcn = (s8)buf[b--]; b > b2; b--)
852 deltaxcn = (deltaxcn << 8) + buf[b];
853 /* Change the current lcn to its new value. */
857 * On NTFS 1.2-, apparently can have lcn == -1 to
858 * indicate a hole. But we haven't verified ourselves
859 * whether it is really the lcn or the deltaxcn that is
860 * -1. So if either is found give us a message so we
861 * can investigate it further!
863 if (vol->major_ver < 3) {
864 if (unlikely(deltaxcn == (LCN)-1))
865 ntfs_error(vol->sb, "lcn delta == -1");
866 if (unlikely(lcn == (LCN)-1))
867 ntfs_error(vol->sb, "lcn == -1");
870 /* Check lcn is not below -1. */
871 if (unlikely(lcn < (LCN)-1)) {
872 ntfs_error(vol->sb, "Invalid LCN < -1 in "
873 "mapping pairs array.");
876 /* Enter the current lcn into the runlist element. */
879 /* Get to the next runlist element. */
881 /* Increment the buffer position to the next mapping pair. */
882 buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1;
884 if (unlikely(buf >= attr_end))
887 * If there is a highest_vcn specified, it must be equal to the final
888 * vcn in the runlist - 1, or something has gone badly wrong.
890 deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn);
891 if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) {
893 ntfs_error(vol->sb, "Corrupt mapping pairs array in "
894 "non-resident attribute.");
897 /* Setup not mapped runlist element if this is the base extent. */
898 if (!attr->data.non_resident.lowest_vcn) {
901 max_cluster = ((sle64_to_cpu(
902 attr->data.non_resident.allocated_size) +
903 vol->cluster_size - 1) >>
904 vol->cluster_size_bits) - 1;
906 * A highest_vcn of zero means this is a single extent
907 * attribute so simply terminate the runlist with LCN_ENOENT).
911 * If there is a difference between the highest_vcn and
912 * the highest cluster, the runlist is either corrupt
913 * or, more likely, there are more extents following
916 if (deltaxcn < max_cluster) {
917 ntfs_debug("More extents to follow; deltaxcn "
918 "= 0x%llx, max_cluster = "
920 (unsigned long long)deltaxcn,
924 vcn += rl[rlpos].length = max_cluster -
926 rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
928 } else if (unlikely(deltaxcn > max_cluster)) {
929 ntfs_error(vol->sb, "Corrupt attribute. "
930 "deltaxcn = 0x%llx, "
931 "max_cluster = 0x%llx",
932 (unsigned long long)deltaxcn,
938 rl[rlpos].lcn = LCN_ENOENT;
939 } else /* Not the base extent. There may be more extents to follow. */
940 rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
942 /* Setup terminating runlist element. */
944 rl[rlpos].length = (s64)0;
945 /* If no existing runlist was specified, we are done. */
947 ntfs_debug("Mapping pairs array successfully decompressed:");
948 ntfs_debug_dump_runlist(rl);
951 /* Now combine the new and old runlists checking for overlaps. */
952 old_rl = ntfs_runlists_merge(old_rl, rl);
953 if (likely(!IS_ERR(old_rl)))
956 ntfs_error(vol->sb, "Failed to merge runlists.");
959 ntfs_error(vol->sb, "Corrupt attribute.");
962 return ERR_PTR(-EIO);
966 * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
967 * @rl: runlist to use for conversion
968 * @vcn: vcn to convert
970 * Convert the virtual cluster number @vcn of an attribute into a logical
971 * cluster number (lcn) of a device using the runlist @rl to map vcns to their
972 * corresponding lcns.
974 * It is up to the caller to serialize access to the runlist @rl.
976 * Since lcns must be >= 0, we use negative return codes with special meaning:
978 * Return code Meaning / Description
979 * ==================================================
980 * LCN_HOLE Hole / not allocated on disk.
981 * LCN_RL_NOT_MAPPED This is part of the runlist which has not been
982 * inserted into the runlist yet.
983 * LCN_ENOENT There is no such vcn in the attribute.
985 * Locking: - The caller must have locked the runlist (for reading or writing).
986 * - This function does not touch the lock, nor does it modify the
989 LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn)
995 * If rl is NULL, assume that we have found an unmapped runlist. The
996 * caller can then attempt to map it and fail appropriately if
1000 return LCN_RL_NOT_MAPPED;
1002 /* Catch out of lower bounds vcn. */
1003 if (unlikely(vcn < rl[0].vcn))
1006 for (i = 0; likely(rl[i].length); i++) {
1007 if (unlikely(vcn < rl[i+1].vcn)) {
1008 if (likely(rl[i].lcn >= (LCN)0))
1009 return rl[i].lcn + (vcn - rl[i].vcn);
1014 * The terminator element is setup to the correct value, i.e. one of
1015 * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
1017 if (likely(rl[i].lcn < (LCN)0))
1019 /* Just in case... We could replace this with BUG() some day. */
1026 * ntfs_rl_find_vcn_nolock - find a vcn in a runlist
1027 * @rl: runlist to search
1030 * Find the virtual cluster number @vcn in the runlist @rl and return the
1031 * address of the runlist element containing the @vcn on success.
1033 * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of
1036 * Locking: The runlist must be locked on entry.
1038 runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl, const VCN vcn)
1041 if (unlikely(!rl || vcn < rl[0].vcn))
1043 while (likely(rl->length)) {
1044 if (unlikely(vcn < rl[1].vcn)) {
1045 if (likely(rl->lcn >= LCN_HOLE))
1051 if (likely(rl->lcn == LCN_ENOENT))
1057 * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
1058 * @n: number for which to get the number of bytes for
1060 * Return the number of bytes required to store @n unambiguously as
1063 * This is used in the context of the mapping pairs array to determine how
1064 * many bytes will be needed in the array to store a given logical cluster
1065 * number (lcn) or a specific run length.
1067 * Return the number of bytes written. This function cannot fail.
1069 static inline int ntfs_get_nr_significant_bytes(const s64 n)
1079 } while (l != 0 && l != -1);
1080 j = (n >> 8 * (i - 1)) & 0xff;
1081 /* If the sign bit is wrong, we need an extra byte. */
1082 if ((n < 0 && j >= 0) || (n > 0 && j < 0))
1088 * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
1089 * @vol: ntfs volume (needed for the ntfs version)
1090 * @rl: locked runlist to determine the size of the mapping pairs of
1091 * @first_vcn: first vcn which to include in the mapping pairs array
1092 * @last_vcn: last vcn which to include in the mapping pairs array
1094 * Walk the locked runlist @rl and calculate the size in bytes of the mapping
1095 * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and
1096 * finishing with vcn @last_vcn.
1098 * A @last_vcn of -1 means end of runlist and in that case the size of the
1099 * mapping pairs array corresponding to the runlist starting at vcn @first_vcn
1100 * and finishing at the end of the runlist is determined.
1102 * This for example allows us to allocate a buffer of the right size when
1103 * building the mapping pairs array.
1105 * If @rl is NULL, just return 1 (for the single terminator byte).
1107 * Return the calculated size in bytes on success. On error, return -errno.
1108 * The following error codes are defined:
1109 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1110 * fully mapped runlists to this function.
1111 * -EIO - The runlist is corrupt.
1113 * Locking: @rl must be locked on entry (either for reading or writing), it
1114 * remains locked throughout, and is left locked upon return.
1116 int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol,
1117 const runlist_element *rl, const VCN first_vcn,
1122 BOOL the_end = FALSE;
1124 BUG_ON(first_vcn < 0);
1125 BUG_ON(last_vcn < -1);
1126 BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
1129 BUG_ON(last_vcn > 0);
1132 /* Skip to runlist element containing @first_vcn. */
1133 while (rl->length && first_vcn >= rl[1].vcn)
1135 if (unlikely((!rl->length && first_vcn > rl->vcn) ||
1136 first_vcn < rl->vcn))
1139 /* Always need the termining zero byte. */
1141 /* Do the first partial run if present. */
1142 if (first_vcn > rl->vcn) {
1143 s64 delta, length = rl->length;
1145 /* We know rl->length != 0 already. */
1146 if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
1149 * If @stop_vcn is given and finishes inside this run, cap the
1152 if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
1153 s64 s1 = last_vcn + 1;
1154 if (unlikely(rl[1].vcn > s1))
1155 length = s1 - rl->vcn;
1158 delta = first_vcn - rl->vcn;
1159 /* Header byte + length. */
1160 rls += 1 + ntfs_get_nr_significant_bytes(length - delta);
1162 * If the logical cluster number (lcn) denotes a hole and we
1163 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1164 * zero space. On earlier NTFS versions we just store the lcn.
1165 * Note: this assumes that on NTFS 1.2-, holes are stored with
1166 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1168 if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
1170 if (likely(rl->lcn >= 0))
1172 /* Change in lcn. */
1173 rls += ntfs_get_nr_significant_bytes(prev_lcn);
1175 /* Go to next runlist element. */
1178 /* Do the full runs. */
1179 for (; rl->length && !the_end; rl++) {
1180 s64 length = rl->length;
1182 if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
1185 * If @stop_vcn is given and finishes inside this run, cap the
1188 if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
1189 s64 s1 = last_vcn + 1;
1190 if (unlikely(rl[1].vcn > s1))
1191 length = s1 - rl->vcn;
1194 /* Header byte + length. */
1195 rls += 1 + ntfs_get_nr_significant_bytes(length);
1197 * If the logical cluster number (lcn) denotes a hole and we
1198 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1199 * zero space. On earlier NTFS versions we just store the lcn.
1200 * Note: this assumes that on NTFS 1.2-, holes are stored with
1201 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1203 if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
1204 /* Change in lcn. */
1205 rls += ntfs_get_nr_significant_bytes(rl->lcn -
1212 if (rl->lcn == LCN_RL_NOT_MAPPED)
1220 * ntfs_write_significant_bytes - write the significant bytes of a number
1221 * @dst: destination buffer to write to
1222 * @dst_max: pointer to last byte of destination buffer for bounds checking
1223 * @n: number whose significant bytes to write
1225 * Store in @dst, the minimum bytes of the number @n which are required to
1226 * identify @n unambiguously as a signed number, taking care not to exceed
1227 * @dest_max, the maximum position within @dst to which we are allowed to
1230 * This is used when building the mapping pairs array of a runlist to compress
1231 * a given logical cluster number (lcn) or a specific run length to the minumum
1234 * Return the number of bytes written on success. On error, i.e. the
1235 * destination buffer @dst is too small, return -ENOSPC.
1237 static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max,
1246 if (unlikely(dst > dst_max))
1248 *dst++ = l & 0xffll;
1251 } while (l != 0 && l != -1);
1252 j = (n >> 8 * (i - 1)) & 0xff;
1253 /* If the sign bit is wrong, we need an extra byte. */
1254 if (n < 0 && j >= 0) {
1255 if (unlikely(dst > dst_max))
1259 } else if (n > 0 && j < 0) {
1260 if (unlikely(dst > dst_max))
1271 * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
1272 * @vol: ntfs volume (needed for the ntfs version)
1273 * @dst: destination buffer to which to write the mapping pairs array
1274 * @dst_len: size of destination buffer @dst in bytes
1275 * @rl: locked runlist for which to build the mapping pairs array
1276 * @first_vcn: first vcn which to include in the mapping pairs array
1277 * @last_vcn: last vcn which to include in the mapping pairs array
1278 * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC
1280 * Create the mapping pairs array from the locked runlist @rl, starting at vcn
1281 * @first_vcn and finishing with vcn @last_vcn and save the array in @dst.
1282 * @dst_len is the size of @dst in bytes and it should be at least equal to the
1283 * value obtained by calling ntfs_get_size_for_mapping_pairs().
1285 * A @last_vcn of -1 means end of runlist and in that case the mapping pairs
1286 * array corresponding to the runlist starting at vcn @first_vcn and finishing
1287 * at the end of the runlist is created.
1289 * If @rl is NULL, just write a single terminator byte to @dst.
1291 * On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
1292 * the first vcn outside the destination buffer. Note that on error, @dst has
1293 * been filled with all the mapping pairs that will fit, thus it can be treated
1294 * as partial success, in that a new attribute extent needs to be created or
1295 * the next extent has to be used and the mapping pairs build has to be
1296 * continued with @first_vcn set to *@stop_vcn.
1298 * Return 0 on success and -errno on error. The following error codes are
1300 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1301 * fully mapped runlists to this function.
1302 * -EIO - The runlist is corrupt.
1303 * -ENOSPC - The destination buffer is too small.
1305 * Locking: @rl must be locked on entry (either for reading or writing), it
1306 * remains locked throughout, and is left locked upon return.
1308 int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
1309 const int dst_len, const runlist_element *rl,
1310 const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn)
1313 s8 *dst_max, *dst_next;
1315 BOOL the_end = FALSE;
1316 s8 len_len, lcn_len;
1318 BUG_ON(first_vcn < 0);
1319 BUG_ON(last_vcn < -1);
1320 BUG_ON(last_vcn >= 0 && first_vcn > last_vcn);
1321 BUG_ON(dst_len < 1);
1324 BUG_ON(last_vcn > 0);
1327 /* Terminator byte. */
1331 /* Skip to runlist element containing @first_vcn. */
1332 while (rl->length && first_vcn >= rl[1].vcn)
1334 if (unlikely((!rl->length && first_vcn > rl->vcn) ||
1335 first_vcn < rl->vcn))
1338 * @dst_max is used for bounds checking in
1339 * ntfs_write_significant_bytes().
1341 dst_max = dst + dst_len - 1;
1343 /* Do the first partial run if present. */
1344 if (first_vcn > rl->vcn) {
1345 s64 delta, length = rl->length;
1347 /* We know rl->length != 0 already. */
1348 if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
1351 * If @stop_vcn is given and finishes inside this run, cap the
1354 if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
1355 s64 s1 = last_vcn + 1;
1356 if (unlikely(rl[1].vcn > s1))
1357 length = s1 - rl->vcn;
1360 delta = first_vcn - rl->vcn;
1362 len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
1364 if (unlikely(len_len < 0))
1367 * If the logical cluster number (lcn) denotes a hole and we
1368 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1369 * zero space. On earlier NTFS versions we just write the lcn
1370 * change. FIXME: Do we need to write the lcn change or just
1371 * the lcn in that case? Not sure as I have never seen this
1372 * case on NT4. - We assume that we just need to write the lcn
1373 * change until someone tells us otherwise... (AIA)
1375 if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
1377 if (likely(rl->lcn >= 0))
1379 /* Write change in lcn. */
1380 lcn_len = ntfs_write_significant_bytes(dst + 1 +
1381 len_len, dst_max, prev_lcn);
1382 if (unlikely(lcn_len < 0))
1386 dst_next = dst + len_len + lcn_len + 1;
1387 if (unlikely(dst_next > dst_max))
1389 /* Update header byte. */
1390 *dst = lcn_len << 4 | len_len;
1391 /* Position at next mapping pairs array element. */
1393 /* Go to next runlist element. */
1396 /* Do the full runs. */
1397 for (; rl->length && !the_end; rl++) {
1398 s64 length = rl->length;
1400 if (unlikely(length < 0 || rl->lcn < LCN_HOLE))
1403 * If @stop_vcn is given and finishes inside this run, cap the
1406 if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) {
1407 s64 s1 = last_vcn + 1;
1408 if (unlikely(rl[1].vcn > s1))
1409 length = s1 - rl->vcn;
1413 len_len = ntfs_write_significant_bytes(dst + 1, dst_max,
1415 if (unlikely(len_len < 0))
1418 * If the logical cluster number (lcn) denotes a hole and we
1419 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1420 * zero space. On earlier NTFS versions we just write the lcn
1421 * change. FIXME: Do we need to write the lcn change or just
1422 * the lcn in that case? Not sure as I have never seen this
1423 * case on NT4. - We assume that we just need to write the lcn
1424 * change until someone tells us otherwise... (AIA)
1426 if (likely(rl->lcn >= 0 || vol->major_ver < 3)) {
1427 /* Write change in lcn. */
1428 lcn_len = ntfs_write_significant_bytes(dst + 1 +
1429 len_len, dst_max, rl->lcn - prev_lcn);
1430 if (unlikely(lcn_len < 0))
1435 dst_next = dst + len_len + lcn_len + 1;
1436 if (unlikely(dst_next > dst_max))
1438 /* Update header byte. */
1439 *dst = lcn_len << 4 | len_len;
1440 /* Position at next mapping pairs array element. */
1448 *stop_vcn = rl->vcn;
1449 /* Add terminator byte. */
1453 if (rl->lcn == LCN_RL_NOT_MAPPED)
1461 * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn
1462 * @vol: ntfs volume (needed for error output)
1463 * @runlist: runlist to truncate
1464 * @new_length: the new length of the runlist in VCNs
1466 * Truncate the runlist described by @runlist as well as the memory buffer
1467 * holding the runlist elements to a length of @new_length VCNs.
1469 * If @new_length lies within the runlist, the runlist elements with VCNs of
1470 * @new_length and above are discarded. As a special case if @new_length is
1471 * zero, the runlist is discarded and set to NULL.
1473 * If @new_length lies beyond the runlist, a sparse runlist element is added to
1474 * the end of the runlist @runlist or if the last runlist element is a sparse
1475 * one already, this is extended.
1477 * Note, no checking is done for unmapped runlist elements. It is assumed that
1478 * the caller has mapped any elements that need to be mapped already.
1480 * Return 0 on success and -errno on error.
1482 * Locking: The caller must hold @runlist->lock for writing.
1484 int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist,
1485 const s64 new_length)
1487 runlist_element *rl;
1490 ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length);
1492 BUG_ON(new_length < 0);
1495 ntfs_debug("Freeing runlist.");
1501 if (unlikely(!rl)) {
1503 * Create a runlist consisting of a sparse runlist element of
1504 * length @new_length followed by a terminator runlist element.
1506 rl = ntfs_malloc_nofs(PAGE_SIZE);
1507 if (unlikely(!rl)) {
1508 ntfs_error(vol->sb, "Not enough memory to allocate "
1509 "runlist element buffer.");
1513 rl[1].length = rl->vcn = 0;
1515 rl[1].vcn = rl->length = new_length;
1516 rl[1].lcn = LCN_ENOENT;
1519 BUG_ON(new_length < rl->vcn);
1520 /* Find @new_length in the runlist. */
1521 while (likely(rl->length && new_length >= rl[1].vcn))
1524 * If not at the end of the runlist we need to shrink it.
1525 * If at the end of the runlist we need to expand it.
1528 runlist_element *trl;
1531 ntfs_debug("Shrinking runlist.");
1532 /* Determine the runlist size. */
1534 while (likely(trl->length))
1536 old_size = trl - runlist->rl + 1;
1537 /* Truncate the run. */
1538 rl->length = new_length - rl->vcn;
1540 * If a run was partially truncated, make the following runlist
1541 * element a terminator.
1548 rl->vcn = new_length;
1551 rl->lcn = LCN_ENOENT;
1552 /* Reallocate memory if necessary. */
1554 int new_size = rl - runlist->rl + 1;
1555 rl = ntfs_rl_realloc(runlist->rl, old_size, new_size);
1557 ntfs_warning(vol->sb, "Failed to shrink "
1558 "runlist buffer. This just "
1559 "wastes a bit of memory "
1560 "temporarily so we ignore it "
1561 "and return success.");
1565 } else if (likely(/* !rl->length && */ new_length > rl->vcn)) {
1566 ntfs_debug("Expanding runlist.");
1568 * If there is a previous runlist element and it is a sparse
1569 * one, extend it. Otherwise need to add a new, sparse runlist
1572 if ((rl > runlist->rl) && ((rl - 1)->lcn == LCN_HOLE))
1573 (rl - 1)->length = new_length - (rl - 1)->vcn;
1575 /* Determine the runlist size. */
1576 old_size = rl - runlist->rl + 1;
1577 /* Reallocate memory if necessary. */
1578 rl = ntfs_rl_realloc(runlist->rl, old_size,
1581 ntfs_error(vol->sb, "Failed to expand runlist "
1582 "buffer, aborting.");
1587 * Set @rl to the same runlist element in the new
1588 * runlist as before in the old runlist.
1591 /* Add a new, sparse runlist element. */
1593 rl->length = new_length - rl->vcn;
1594 /* Add a new terminator runlist element. */
1598 rl->vcn = new_length;
1599 rl->lcn = LCN_ENOENT;
1600 } else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ {
1601 /* Runlist already has same size as requested. */
1602 rl->lcn = LCN_ENOENT;
1604 ntfs_debug("Done.");
1609 * ntfs_rl_punch_nolock - punch a hole into a runlist
1610 * @vol: ntfs volume (needed for error output)
1611 * @runlist: runlist to punch a hole into
1612 * @start: starting VCN of the hole to be created
1613 * @length: size of the hole to be created in units of clusters
1615 * Punch a hole into the runlist @runlist starting at VCN @start and of size
1618 * Return 0 on success and -errno on error, in which case @runlist has not been
1621 * If @start and/or @start + @length are outside the runlist return error code
1624 * If the runlist contains unmapped or error elements between @start and @start
1625 * + @length return error code -EINVAL.
1627 * Locking: The caller must hold @runlist->lock for writing.
1629 int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist,
1630 const VCN start, const s64 length)
1632 const VCN end = start + length;
1634 runlist_element *rl, *rl_end, *rl_real_end, *trl;
1636 BOOL lcn_fixup = FALSE;
1638 ntfs_debug("Entering for start 0x%llx, length 0x%llx.",
1639 (long long)start, (long long)length);
1645 if (unlikely(!rl)) {
1646 if (likely(!start && !length))
1650 /* Find @start in the runlist. */
1651 while (likely(rl->length && start >= rl[1].vcn))
1654 /* Find @end in the runlist. */
1655 while (likely(rl_end->length && end >= rl_end[1].vcn)) {
1656 /* Verify there are no unmapped or error elements. */
1657 if (unlikely(rl_end->lcn < LCN_HOLE))
1661 /* Check the last element. */
1662 if (unlikely(rl_end->length && rl_end->lcn < LCN_HOLE))
1664 /* This covers @start being out of bounds, too. */
1665 if (!rl_end->length && end > rl_end->vcn)
1671 rl_real_end = rl_end;
1672 /* Determine the runlist size. */
1673 while (likely(rl_real_end->length))
1675 old_size = rl_real_end - runlist->rl + 1;
1676 /* If @start is in a hole simply extend the hole. */
1677 if (rl->lcn == LCN_HOLE) {
1679 * If both @start and @end are in the same sparse run, we are
1682 if (end <= rl[1].vcn) {
1683 ntfs_debug("Done (requested hole is already sparse).");
1687 /* Extend the hole. */
1688 rl->length = end - rl->vcn;
1689 /* If @end is in a hole, merge it with the current one. */
1690 if (rl_end->lcn == LCN_HOLE) {
1692 rl->length = rl_end->vcn - rl->vcn;
1694 /* We have done the hole. Now deal with the remaining tail. */
1696 /* Cut out all runlist elements up to @end. */
1698 memmove(rl, rl_end, (rl_real_end - rl_end + 1) *
1700 /* Adjust the beginning of the tail if necessary. */
1701 if (end > rl->vcn) {
1702 s64 delta = end - rl->vcn;
1704 rl->length -= delta;
1705 /* Only adjust the lcn if it is real. */
1710 /* Reallocate memory if the allocation changed. */
1712 rl = ntfs_rl_realloc(runlist->rl, old_size,
1713 old_size - (rl_end - rl));
1715 ntfs_warning(vol->sb, "Failed to shrink "
1716 "runlist buffer. This just "
1717 "wastes a bit of memory "
1718 "temporarily so we ignore it "
1719 "and return success.");
1723 ntfs_debug("Done (extend hole).");
1727 * If @start is at the beginning of a run things are easier as there is
1728 * no need to split the first run.
1730 if (start == rl->vcn) {
1732 * @start is at the beginning of a run.
1734 * If the previous run is sparse, extend its hole.
1736 * If @end is not in the same run, switch the run to be sparse
1737 * and extend the newly created hole.
1739 * Thus both of these cases reduce the problem to the above
1740 * case of "@start is in a hole".
1742 if (rl > runlist->rl && (rl - 1)->lcn == LCN_HOLE) {
1746 if (end >= rl[1].vcn) {
1751 * The final case is when @end is in the same run as @start.
1752 * For this need to split the run into two. One run for the
1753 * sparse region between the beginning of the old run, i.e.
1754 * @start, and @end and one for the remaining non-sparse
1755 * region, i.e. between @end and the end of the old run.
1757 trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1);
1761 if (runlist->rl != trl) {
1762 rl = trl + (rl - runlist->rl);
1763 rl_end = trl + (rl_end - runlist->rl);
1764 rl_real_end = trl + (rl_real_end - runlist->rl);
1768 /* Shift all the runs up by one. */
1769 memmove(rl + 1, rl, (rl_real_end - rl + 1) * sizeof(*rl));
1770 /* Finally, setup the two split runs. */
1772 rl->length = length;
1775 /* Only adjust the lcn if it is real. */
1776 if (rl->lcn >= 0 || lcn_fixup)
1778 rl->length -= length;
1779 ntfs_debug("Done (split one).");
1783 * @start is neither in a hole nor at the beginning of a run.
1785 * If @end is in a hole, things are easier as simply truncating the run
1786 * @start is in to end at @start - 1, deleting all runs after that up
1787 * to @end, and finally extending the beginning of the run @end is in
1788 * to be @start is all that is needed.
1790 if (rl_end->lcn == LCN_HOLE) {
1791 /* Truncate the run containing @start. */
1792 rl->length = start - rl->vcn;
1794 /* Cut out all runlist elements up to @end. */
1796 memmove(rl, rl_end, (rl_real_end - rl_end + 1) *
1798 /* Extend the beginning of the run @end is in to be @start. */
1800 rl->length = rl[1].vcn - start;
1801 goto shrink_allocation;
1804 * If @end is not in a hole there are still two cases to distinguish.
1805 * Either @end is or is not in the same run as @start.
1807 * The second case is easier as it can be reduced to an already solved
1808 * problem by truncating the run @start is in to end at @start - 1.
1809 * Then, if @end is in the next run need to split the run into a sparse
1810 * run followed by a non-sparse run (already covered above) and if @end
1811 * is not in the next run switching it to be sparse, again reduces the
1812 * problem to the already covered case of "@start is in a hole".
1814 if (end >= rl[1].vcn) {
1816 * If @end is not in the next run, reduce the problem to the
1817 * case of "@start is in a hole".
1819 if (rl[1].length && end >= rl[2].vcn) {
1820 /* Truncate the run containing @start. */
1821 rl->length = start - rl->vcn;
1827 trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1);
1831 if (runlist->rl != trl) {
1832 rl = trl + (rl - runlist->rl);
1833 rl_end = trl + (rl_end - runlist->rl);
1834 rl_real_end = trl + (rl_real_end - runlist->rl);
1837 /* Truncate the run containing @start. */
1838 rl->length = start - rl->vcn;
1841 * @end is in the next run, reduce the problem to the case
1842 * where "@start is at the beginning of a run and @end is in
1843 * the same run as @start".
1845 delta = rl->vcn - start;
1849 /* Need this in case the lcn just became negative. */
1852 rl->length += delta;
1856 * The first case from above, i.e. @end is in the same run as @start.
1857 * We need to split the run into three. One run for the non-sparse
1858 * region between the beginning of the old run and @start, one for the
1859 * sparse region between @start and @end, and one for the remaining
1860 * non-sparse region, i.e. between @end and the end of the old run.
1862 trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 2);
1866 if (runlist->rl != trl) {
1867 rl = trl + (rl - runlist->rl);
1868 rl_end = trl + (rl_end - runlist->rl);
1869 rl_real_end = trl + (rl_real_end - runlist->rl);
1872 /* Shift all the runs up by two. */
1873 memmove(rl + 2, rl, (rl_real_end - rl + 1) * sizeof(*rl));
1874 /* Finally, setup the three split runs. */
1875 rl->length = start - rl->vcn;
1879 rl->length = length;
1881 delta = end - rl->vcn;
1884 rl->length -= delta;
1885 ntfs_debug("Done (split both).");
1888 ntfs_error(vol->sb, "Not enough memory to extend runlist buffer.");
1892 #endif /* NTFS_RW */