2 * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project.
4 * Copyright (c) 2001-2007 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 /* We can merge unmapped regions even if they are misaligned. */
162 if ((dst
->lcn
== LCN_RL_NOT_MAPPED
) && (src
->lcn
== LCN_RL_NOT_MAPPED
))
164 /* If the runs are misaligned, we cannot merge them. */
165 if ((dst
->vcn
+ dst
->length
) != src
->vcn
)
167 /* If both runs are non-sparse and contiguous, we can merge them. */
168 if ((dst
->lcn
>= 0) && (src
->lcn
>= 0) &&
169 ((dst
->lcn
+ dst
->length
) == src
->lcn
))
171 /* If we are merging two holes, we can merge them. */
172 if ((dst
->lcn
== LCN_HOLE
) && (src
->lcn
== LCN_HOLE
))
179 * __ntfs_rl_merge - merge two runlists without testing if they can be merged
180 * @dst: original, destination runlist
181 * @src: new runlist to merge with @dst
183 * Merge the two runlists, writing into the destination runlist @dst. The
184 * caller must make sure the runlists can be merged or this will corrupt the
185 * destination runlist.
187 * It is up to the caller to serialize access to the runlists @dst and @src.
189 static inline void __ntfs_rl_merge(runlist_element
*dst
, runlist_element
*src
)
191 dst
->length
+= src
->length
;
195 * ntfs_rl_append - append a runlist after a given element
196 * @dst: original runlist to be worked on
197 * @dsize: number of elements in @dst (including end marker)
198 * @src: runlist to be inserted into @dst
199 * @ssize: number of elements in @src (excluding end marker)
200 * @loc: append the new runlist @src after this element in @dst
202 * Append the runlist @src after element @loc in @dst. Merge the right end of
203 * the new runlist, if necessary. Adjust the size of the hole before the
206 * It is up to the caller to serialize access to the runlists @dst and @src.
208 * On success, return a pointer to the new, combined, runlist. Note, both
209 * runlists @dst and @src are deallocated before returning so you cannot use
210 * the pointers for anything any more. (Strictly speaking the returned runlist
211 * may be the same as @dst but this is irrelevant.)
213 * On error, return -errno. Both runlists are left unmodified. The following
214 * error codes are defined:
215 * -ENOMEM - Not enough memory to allocate runlist array.
216 * -EINVAL - Invalid parameters were passed in.
218 static inline runlist_element
*ntfs_rl_append(runlist_element
*dst
,
219 int dsize
, runlist_element
*src
, int ssize
, int loc
)
221 bool right
= false; /* Right end of @src needs merging. */
222 int marker
; /* End of the inserted runs. */
227 /* First, check if the right hand end needs merging. */
228 if ((loc
+ 1) < dsize
)
229 right
= ntfs_are_rl_mergeable(src
+ ssize
- 1, dst
+ loc
+ 1);
231 /* Space required: @dst size + @src size, less one if we merged. */
232 dst
= ntfs_rl_realloc(dst
, dsize
, dsize
+ ssize
- right
);
236 * We are guaranteed to succeed from here so can start modifying the
240 /* First, merge the right hand end, if necessary. */
242 __ntfs_rl_merge(src
+ ssize
- 1, dst
+ loc
+ 1);
244 /* First run after the @src runs that have been inserted. */
245 marker
= loc
+ ssize
+ 1;
247 /* Move the tail of @dst out of the way, then copy in @src. */
248 ntfs_rl_mm(dst
, marker
, loc
+ 1 + right
, dsize
- (loc
+ 1 + right
));
249 ntfs_rl_mc(dst
, loc
+ 1, src
, 0, ssize
);
251 /* Adjust the size of the preceding hole. */
252 dst
[loc
].length
= dst
[loc
+ 1].vcn
- dst
[loc
].vcn
;
254 /* We may have changed the length of the file, so fix the end marker */
255 if (dst
[marker
].lcn
== LCN_ENOENT
)
256 dst
[marker
].vcn
= dst
[marker
- 1].vcn
+ dst
[marker
- 1].length
;
262 * ntfs_rl_insert - insert a runlist into another
263 * @dst: original runlist to be worked on
264 * @dsize: number of elements in @dst (including end marker)
265 * @src: new runlist to be inserted
266 * @ssize: number of elements in @src (excluding end marker)
267 * @loc: insert the new runlist @src before this element in @dst
269 * Insert the runlist @src before element @loc in the runlist @dst. Merge the
270 * left end of the new runlist, if necessary. Adjust the size of the hole
271 * after the inserted runlist.
273 * It is up to the caller to serialize access to the runlists @dst and @src.
275 * On success, return a pointer to the new, combined, runlist. Note, both
276 * runlists @dst and @src are deallocated before returning so you cannot use
277 * the pointers for anything any more. (Strictly speaking the returned runlist
278 * may be the same as @dst but this is irrelevant.)
280 * On error, return -errno. Both runlists are left unmodified. The following
281 * error codes are defined:
282 * -ENOMEM - Not enough memory to allocate runlist array.
283 * -EINVAL - Invalid parameters were passed in.
285 static inline runlist_element
*ntfs_rl_insert(runlist_element
*dst
,
286 int dsize
, runlist_element
*src
, int ssize
, int loc
)
288 bool left
= false; /* Left end of @src needs merging. */
289 bool disc
= false; /* Discontinuity between @dst and @src. */
290 int marker
; /* End of the inserted runs. */
296 * disc => Discontinuity between the end of @dst and the start of @src.
297 * This means we might need to insert a "not mapped" run.
300 disc
= (src
[0].vcn
> 0);
304 left
= ntfs_are_rl_mergeable(dst
+ loc
- 1, src
);
306 merged_length
= dst
[loc
- 1].length
;
308 merged_length
+= src
->length
;
310 disc
= (src
[0].vcn
> dst
[loc
- 1].vcn
+ merged_length
);
313 * Space required: @dst size + @src size, less one if we merged, plus
314 * one if there was a discontinuity.
316 dst
= ntfs_rl_realloc(dst
, dsize
, dsize
+ ssize
- left
+ disc
);
320 * We are guaranteed to succeed from here so can start modifying the
324 __ntfs_rl_merge(dst
+ loc
- 1, src
);
326 * First run after the @src runs that have been inserted.
327 * Nominally, @marker equals @loc + @ssize, i.e. location + number of
328 * runs in @src. However, if @left, then the first run in @src has
329 * been merged with one in @dst. And if @disc, then @dst and @src do
330 * not meet and we need an extra run to fill the gap.
332 marker
= loc
+ ssize
- left
+ disc
;
334 /* Move the tail of @dst out of the way, then copy in @src. */
335 ntfs_rl_mm(dst
, marker
, loc
, dsize
- loc
);
336 ntfs_rl_mc(dst
, loc
+ disc
, src
, left
, ssize
- left
);
338 /* Adjust the VCN of the first run after the insertion... */
339 dst
[marker
].vcn
= dst
[marker
- 1].vcn
+ dst
[marker
- 1].length
;
340 /* ... and the length. */
341 if (dst
[marker
].lcn
== LCN_HOLE
|| dst
[marker
].lcn
== LCN_RL_NOT_MAPPED
)
342 dst
[marker
].length
= dst
[marker
+ 1].vcn
- dst
[marker
].vcn
;
344 /* Writing beyond the end of the file and there is a discontinuity. */
347 dst
[loc
].vcn
= dst
[loc
- 1].vcn
+ dst
[loc
- 1].length
;
348 dst
[loc
].length
= dst
[loc
+ 1].vcn
- dst
[loc
].vcn
;
351 dst
[loc
].length
= dst
[loc
+ 1].vcn
;
353 dst
[loc
].lcn
= LCN_RL_NOT_MAPPED
;
359 * ntfs_rl_replace - overwrite a runlist element with another runlist
360 * @dst: original runlist to be worked on
361 * @dsize: number of elements in @dst (including end marker)
362 * @src: new runlist to be inserted
363 * @ssize: number of elements in @src (excluding end marker)
364 * @loc: index in runlist @dst to overwrite with @src
366 * Replace the runlist element @dst at @loc with @src. Merge the left and
367 * right ends of the inserted runlist, if necessary.
369 * It is up to the caller to serialize access to the runlists @dst and @src.
371 * On success, return a pointer to the new, combined, runlist. Note, both
372 * runlists @dst and @src are deallocated before returning so you cannot use
373 * the pointers for anything any more. (Strictly speaking the returned runlist
374 * may be the same as @dst but this is irrelevant.)
376 * On error, return -errno. Both runlists are left unmodified. The following
377 * error codes are defined:
378 * -ENOMEM - Not enough memory to allocate runlist array.
379 * -EINVAL - Invalid parameters were passed in.
381 static inline runlist_element
*ntfs_rl_replace(runlist_element
*dst
,
382 int dsize
, runlist_element
*src
, int ssize
, int loc
)
385 bool left
= false; /* Left end of @src needs merging. */
386 bool right
= false; /* Right end of @src needs merging. */
387 int tail
; /* Start of tail of @dst. */
388 int marker
; /* End of the inserted runs. */
393 /* First, see if the left and right ends need merging. */
394 if ((loc
+ 1) < dsize
)
395 right
= ntfs_are_rl_mergeable(src
+ ssize
- 1, dst
+ loc
+ 1);
397 left
= ntfs_are_rl_mergeable(dst
+ loc
- 1, src
);
399 * Allocate some space. We will need less if the left, right, or both
400 * ends get merged. The -1 accounts for the run being replaced.
402 delta
= ssize
- 1 - left
- right
;
404 dst
= ntfs_rl_realloc(dst
, dsize
, dsize
+ delta
);
409 * We are guaranteed to succeed from here so can start modifying the
413 /* First, merge the left and right ends, if necessary. */
415 __ntfs_rl_merge(src
+ ssize
- 1, dst
+ loc
+ 1);
417 __ntfs_rl_merge(dst
+ loc
- 1, src
);
419 * Offset of the tail of @dst. This needs to be moved out of the way
420 * to make space for the runs to be copied from @src, i.e. the first
421 * run of the tail of @dst.
422 * Nominally, @tail equals @loc + 1, i.e. location, skipping the
423 * replaced run. However, if @right, then one of @dst's runs is
424 * already merged into @src.
426 tail
= loc
+ right
+ 1;
428 * First run after the @src runs that have been inserted, i.e. where
429 * the tail of @dst needs to be moved to.
430 * Nominally, @marker equals @loc + @ssize, i.e. location + number of
431 * runs in @src. However, if @left, then the first run in @src has
432 * been merged with one in @dst.
434 marker
= loc
+ ssize
- left
;
436 /* Move the tail of @dst out of the way, then copy in @src. */
437 ntfs_rl_mm(dst
, marker
, tail
, dsize
- tail
);
438 ntfs_rl_mc(dst
, loc
, src
, left
, ssize
- left
);
440 /* We may have changed the length of the file, so fix the end marker. */
441 if (dsize
- tail
> 0 && dst
[marker
].lcn
== LCN_ENOENT
)
442 dst
[marker
].vcn
= dst
[marker
- 1].vcn
+ dst
[marker
- 1].length
;
447 * ntfs_rl_split - insert a runlist into the centre of a hole
448 * @dst: original runlist to be worked on
449 * @dsize: number of elements in @dst (including end marker)
450 * @src: new runlist to be inserted
451 * @ssize: number of elements in @src (excluding end marker)
452 * @loc: index in runlist @dst at which to split and insert @src
454 * Split the runlist @dst at @loc into two and insert @new in between the two
455 * fragments. No merging of runlists is necessary. Adjust the size of the
458 * It is up to the caller to serialize access to the runlists @dst and @src.
460 * On success, return a pointer to the new, combined, runlist. Note, both
461 * runlists @dst and @src are deallocated before returning so you cannot use
462 * the pointers for anything any more. (Strictly speaking the returned runlist
463 * may be the same as @dst but this is irrelevant.)
465 * On error, return -errno. Both runlists are left unmodified. The following
466 * error codes are defined:
467 * -ENOMEM - Not enough memory to allocate runlist array.
468 * -EINVAL - Invalid parameters were passed in.
470 static inline runlist_element
*ntfs_rl_split(runlist_element
*dst
, int dsize
,
471 runlist_element
*src
, int ssize
, int loc
)
476 /* Space required: @dst size + @src size + one new hole. */
477 dst
= ntfs_rl_realloc(dst
, dsize
, dsize
+ ssize
+ 1);
481 * We are guaranteed to succeed from here so can start modifying the
485 /* Move the tail of @dst out of the way, then copy in @src. */
486 ntfs_rl_mm(dst
, loc
+ 1 + ssize
, loc
, dsize
- loc
);
487 ntfs_rl_mc(dst
, loc
+ 1, src
, 0, ssize
);
489 /* Adjust the size of the holes either size of @src. */
490 dst
[loc
].length
= dst
[loc
+1].vcn
- dst
[loc
].vcn
;
491 dst
[loc
+ssize
+1].vcn
= dst
[loc
+ssize
].vcn
+ dst
[loc
+ssize
].length
;
492 dst
[loc
+ssize
+1].length
= dst
[loc
+ssize
+2].vcn
- dst
[loc
+ssize
+1].vcn
;
498 * ntfs_runlists_merge - merge two runlists into one
499 * @drl: original runlist to be worked on
500 * @srl: new runlist to be merged into @drl
502 * First we sanity check the two runlists @srl and @drl to make sure that they
503 * are sensible and can be merged. The runlist @srl must be either after the
504 * runlist @drl or completely within a hole (or unmapped region) in @drl.
506 * It is up to the caller to serialize access to the runlists @drl and @srl.
508 * Merging of runlists is necessary in two cases:
509 * 1. When attribute lists are used and a further extent is being mapped.
510 * 2. When new clusters are allocated to fill a hole or extend a file.
512 * There are four possible ways @srl can be merged. It can:
513 * - be inserted at the beginning of a hole,
514 * - split the hole in two and be inserted between the two fragments,
515 * - be appended at the end of a hole, or it can
516 * - replace the whole hole.
517 * It can also be appended to the end of the runlist, which is just a variant
518 * of the insert case.
520 * On success, return a pointer to the new, combined, runlist. Note, both
521 * runlists @drl and @srl are deallocated before returning so you cannot use
522 * the pointers for anything any more. (Strictly speaking the returned runlist
523 * may be the same as @dst but this is irrelevant.)
525 * On error, return -errno. Both runlists are left unmodified. The following
526 * error codes are defined:
527 * -ENOMEM - Not enough memory to allocate runlist array.
528 * -EINVAL - Invalid parameters were passed in.
529 * -ERANGE - The runlists overlap and cannot be merged.
531 runlist_element
*ntfs_runlists_merge(runlist_element
*drl
,
532 runlist_element
*srl
)
534 int di
, si
; /* Current index into @[ds]rl. */
535 int sstart
; /* First index with lcn > LCN_RL_NOT_MAPPED. */
536 int dins
; /* Index into @drl at which to insert @srl. */
537 int dend
, send
; /* Last index into @[ds]rl. */
538 int dfinal
, sfinal
; /* The last index into @[ds]rl with
545 ntfs_debug_dump_runlist(drl
);
547 ntfs_debug_dump_runlist(srl
);
550 /* Check for silly calling... */
553 if (IS_ERR(srl
) || IS_ERR(drl
))
554 return ERR_PTR(-EINVAL
);
556 /* Check for the case where the first mapping is being done now. */
557 if (unlikely(!drl
)) {
559 /* Complete the source runlist if necessary. */
560 if (unlikely(drl
[0].vcn
)) {
561 /* Scan to the end of the source runlist. */
562 for (dend
= 0; likely(drl
[dend
].length
); dend
++)
565 drl
= ntfs_rl_realloc(drl
, dend
, dend
+ 1);
568 /* Insert start element at the front of the runlist. */
569 ntfs_rl_mm(drl
, 1, 0, dend
);
571 drl
[0].lcn
= LCN_RL_NOT_MAPPED
;
572 drl
[0].length
= drl
[1].vcn
;
579 /* Skip any unmapped start element(s) in the source runlist. */
580 while (srl
[si
].length
&& srl
[si
].lcn
< LCN_HOLE
)
583 /* Can't have an entirely unmapped source runlist. */
584 BUG_ON(!srl
[si
].length
);
586 /* Record the starting points. */
590 * Skip forward in @drl until we reach the position where @srl needs to
591 * be inserted. If we reach the end of @drl, @srl just needs to be
594 for (; drl
[di
].length
; di
++) {
595 if (drl
[di
].vcn
+ drl
[di
].length
> srl
[sstart
].vcn
)
600 /* Sanity check for illegal overlaps. */
601 if ((drl
[di
].vcn
== srl
[si
].vcn
) && (drl
[di
].lcn
>= 0) &&
602 (srl
[si
].lcn
>= 0)) {
603 ntfs_error(NULL
, "Run lists overlap. Cannot merge!");
604 return ERR_PTR(-ERANGE
);
607 /* Scan to the end of both runlists in order to know their sizes. */
608 for (send
= si
; srl
[send
].length
; send
++)
610 for (dend
= di
; drl
[dend
].length
; dend
++)
613 if (srl
[send
].lcn
== LCN_ENOENT
)
614 marker_vcn
= srl
[marker
= send
].vcn
;
616 /* Scan to the last element with lcn >= LCN_HOLE. */
617 for (sfinal
= send
; sfinal
>= 0 && srl
[sfinal
].lcn
< LCN_HOLE
; sfinal
--)
619 for (dfinal
= dend
; dfinal
>= 0 && drl
[dfinal
].lcn
< LCN_HOLE
; dfinal
--)
625 int ds
= dend
+ 1; /* Number of elements in drl & srl */
626 int ss
= sfinal
- sstart
+ 1;
628 start
= ((drl
[dins
].lcn
< LCN_RL_NOT_MAPPED
) || /* End of file */
629 (drl
[dins
].vcn
== srl
[sstart
].vcn
)); /* Start of hole */
630 finish
= ((drl
[dins
].lcn
>= LCN_RL_NOT_MAPPED
) && /* End of file */
631 ((drl
[dins
].vcn
+ drl
[dins
].length
) <= /* End of hole */
632 (srl
[send
- 1].vcn
+ srl
[send
- 1].length
)));
634 /* Or we will lose an end marker. */
635 if (finish
&& !drl
[dins
].length
)
637 if (marker
&& (drl
[dins
].vcn
+ drl
[dins
].length
> srl
[send
- 1].vcn
))
641 drl
= ntfs_rl_replace(drl
, ds
, srl
+ sstart
, ss
, dins
);
643 drl
= ntfs_rl_insert(drl
, ds
, srl
+ sstart
, ss
, dins
);
646 drl
= ntfs_rl_append(drl
, ds
, srl
+ sstart
, ss
, dins
);
648 drl
= ntfs_rl_split(drl
, ds
, srl
+ sstart
, ss
, dins
);
651 ntfs_error(NULL
, "Merge failed.");
656 ntfs_debug("Triggering marker code.");
657 for (ds
= dend
; drl
[ds
].length
; ds
++)
659 /* We only need to care if @srl ended after @drl. */
660 if (drl
[ds
].vcn
<= marker_vcn
) {
663 if (drl
[ds
].vcn
== marker_vcn
) {
664 ntfs_debug("Old marker = 0x%llx, replacing "
668 drl
[ds
].lcn
= LCN_ENOENT
;
672 * We need to create an unmapped runlist element in
673 * @drl or extend an existing one before adding the
676 if (drl
[ds
].lcn
== LCN_ENOENT
) {
680 if (drl
[ds
].lcn
!= LCN_RL_NOT_MAPPED
) {
681 /* Add an unmapped runlist element. */
683 drl
= ntfs_rl_realloc_nofail(drl
, ds
,
688 /* Need to set vcn if it isn't set already. */
690 drl
[ds
].vcn
= drl
[ds
- 1].vcn
+
692 drl
[ds
].lcn
= LCN_RL_NOT_MAPPED
;
693 /* We now used up a slot. */
696 drl
[ds
].length
= marker_vcn
- drl
[ds
].vcn
;
697 /* Finally add the ENOENT terminator. */
700 drl
= ntfs_rl_realloc_nofail(drl
, ds
, ds
+ 1);
701 drl
[ds
].vcn
= marker_vcn
;
702 drl
[ds
].lcn
= LCN_ENOENT
;
703 drl
[ds
].length
= (s64
)0;
709 /* The merge was completed successfully. */
710 ntfs_debug("Merged runlist:");
711 ntfs_debug_dump_runlist(drl
);
715 runlist_element
*ntfs_mapping_pairs_decompress(const ntfs_volume
*vol
,
716 const ATTR_RECORD
*attr
, runlist_element
*old_rl
)
718 VCN vcn
; /* Current vcn. */
719 LCN lcn
; /* Current lcn. */
720 s64 deltaxcn
; /* Change in [vl]cn. */
721 runlist_element
*rl
; /* The output runlist. */
722 u8
*buf
; /* Current position in mapping pairs array. */
723 u8
*attr_end
; /* End of attribute. */
724 int rlsize
; /* Size of runlist buffer. */
725 u16 rlpos
; /* Current runlist position in units of
727 u8 b
; /* Current byte offset in buf. */
730 /* Make sure attr exists and is non-resident. */
731 if (!attr
|| !attr
->non_resident
|| sle64_to_cpu(
732 attr
->data
.non_resident
.lowest_vcn
) < (VCN
)0) {
733 ntfs_error(vol
->sb
, "Invalid arguments.");
734 return ERR_PTR(-EINVAL
);
737 /* Start at vcn = lowest_vcn and lcn 0. */
738 vcn
= sle64_to_cpu(attr
->data
.non_resident
.lowest_vcn
);
740 /* Get start of the mapping pairs array. */
741 buf
= (u8
*)attr
+ le16_to_cpu(
742 attr
->data
.non_resident
.mapping_pairs_offset
);
743 attr_end
= (u8
*)attr
+ le32_to_cpu(attr
->length
);
744 if (unlikely(buf
< (u8
*)attr
|| buf
> attr_end
)) {
745 ntfs_error(vol
->sb
, "Corrupt attribute.");
746 return ERR_PTR(-EIO
);
748 /* If the mapping pairs array is valid but empty, nothing to do. */
751 /* Current position in runlist array. */
753 /* Allocate first page and set current runlist size to one page. */
754 rl
= ntfs_malloc_nofs(rlsize
= PAGE_SIZE
);
756 return ERR_PTR(-ENOMEM
);
757 /* Insert unmapped starting element if necessary. */
760 rl
->lcn
= LCN_RL_NOT_MAPPED
;
764 while (buf
< attr_end
&& *buf
) {
766 * Allocate more memory if needed, including space for the
767 * not-mapped and terminator elements. ntfs_malloc_nofs()
768 * operates on whole pages only.
770 if (((rlpos
+ 3) * sizeof(*old_rl
)) > rlsize
) {
771 runlist_element
*rl2
;
773 rl2
= ntfs_malloc_nofs(rlsize
+ (int)PAGE_SIZE
);
774 if (unlikely(!rl2
)) {
776 return ERR_PTR(-ENOMEM
);
778 memcpy(rl2
, rl
, rlsize
);
783 /* Enter the current vcn into the current runlist element. */
786 * Get the change in vcn, i.e. the run length in clusters.
787 * Doing it this way ensures that we signextend negative values.
788 * A negative run length doesn't make any sense, but hey, I
789 * didn't make up the NTFS specs and Windows NT4 treats the run
790 * length as a signed value so that's how it is...
794 if (unlikely(buf
+ b
> attr_end
))
796 for (deltaxcn
= (s8
)buf
[b
--]; b
; b
--)
797 deltaxcn
= (deltaxcn
<< 8) + buf
[b
];
798 } else { /* The length entry is compulsory. */
799 ntfs_error(vol
->sb
, "Missing length entry in mapping "
804 * Assume a negative length to indicate data corruption and
805 * hence clean-up and return NULL.
807 if (unlikely(deltaxcn
< 0)) {
808 ntfs_error(vol
->sb
, "Invalid length in mapping pairs "
813 * Enter the current run length into the current runlist
816 rl
[rlpos
].length
= deltaxcn
;
817 /* Increment the current vcn by the current run length. */
820 * There might be no lcn change at all, as is the case for
821 * sparse clusters on NTFS 3.0+, in which case we set the lcn
825 rl
[rlpos
].lcn
= LCN_HOLE
;
827 /* Get the lcn change which really can be negative. */
829 b
= b2
+ ((*buf
>> 4) & 0xf);
830 if (buf
+ b
> attr_end
)
832 for (deltaxcn
= (s8
)buf
[b
--]; b
> b2
; b
--)
833 deltaxcn
= (deltaxcn
<< 8) + buf
[b
];
834 /* Change the current lcn to its new value. */
838 * On NTFS 1.2-, apparently can have lcn == -1 to
839 * indicate a hole. But we haven't verified ourselves
840 * whether it is really the lcn or the deltaxcn that is
841 * -1. So if either is found give us a message so we
842 * can investigate it further!
844 if (vol
->major_ver
< 3) {
845 if (unlikely(deltaxcn
== (LCN
)-1))
846 ntfs_error(vol
->sb
, "lcn delta == -1");
847 if (unlikely(lcn
== (LCN
)-1))
848 ntfs_error(vol
->sb
, "lcn == -1");
851 /* Check lcn is not below -1. */
852 if (unlikely(lcn
< (LCN
)-1)) {
853 ntfs_error(vol
->sb
, "Invalid LCN < -1 in "
854 "mapping pairs array.");
857 /* Enter the current lcn into the runlist element. */
860 /* Get to the next runlist element. */
862 /* Increment the buffer position to the next mapping pair. */
863 buf
+= (*buf
& 0xf) + ((*buf
>> 4) & 0xf) + 1;
865 if (unlikely(buf
>= attr_end
))
868 * If there is a highest_vcn specified, it must be equal to the final
869 * vcn in the runlist - 1, or something has gone badly wrong.
871 deltaxcn
= sle64_to_cpu(attr
->data
.non_resident
.highest_vcn
);
872 if (unlikely(deltaxcn
&& vcn
- 1 != deltaxcn
)) {
874 ntfs_error(vol
->sb
, "Corrupt mapping pairs array in "
875 "non-resident attribute.");
878 /* Setup not mapped runlist element if this is the base extent. */
879 if (!attr
->data
.non_resident
.lowest_vcn
) {
882 max_cluster
= ((sle64_to_cpu(
883 attr
->data
.non_resident
.allocated_size
) +
884 vol
->cluster_size
- 1) >>
885 vol
->cluster_size_bits
) - 1;
887 * A highest_vcn of zero means this is a single extent
888 * attribute so simply terminate the runlist with LCN_ENOENT).
892 * If there is a difference between the highest_vcn and
893 * the highest cluster, the runlist is either corrupt
894 * or, more likely, there are more extents following
897 if (deltaxcn
< max_cluster
) {
898 ntfs_debug("More extents to follow; deltaxcn "
899 "= 0x%llx, max_cluster = "
901 (unsigned long long)deltaxcn
,
905 vcn
+= rl
[rlpos
].length
= max_cluster
-
907 rl
[rlpos
].lcn
= LCN_RL_NOT_MAPPED
;
909 } else if (unlikely(deltaxcn
> max_cluster
)) {
910 ntfs_error(vol
->sb
, "Corrupt attribute. "
911 "deltaxcn = 0x%llx, "
912 "max_cluster = 0x%llx",
913 (unsigned long long)deltaxcn
,
919 rl
[rlpos
].lcn
= LCN_ENOENT
;
920 } else /* Not the base extent. There may be more extents to follow. */
921 rl
[rlpos
].lcn
= LCN_RL_NOT_MAPPED
;
923 /* Setup terminating runlist element. */
925 rl
[rlpos
].length
= (s64
)0;
926 /* If no existing runlist was specified, we are done. */
928 ntfs_debug("Mapping pairs array successfully decompressed:");
929 ntfs_debug_dump_runlist(rl
);
932 /* Now combine the new and old runlists checking for overlaps. */
933 old_rl
= ntfs_runlists_merge(old_rl
, rl
);
934 if (likely(!IS_ERR(old_rl
)))
937 ntfs_error(vol
->sb
, "Failed to merge runlists.");
940 ntfs_error(vol
->sb
, "Corrupt attribute.");
943 return ERR_PTR(-EIO
);
947 * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
948 * @rl: runlist to use for conversion
949 * @vcn: vcn to convert
951 * Convert the virtual cluster number @vcn of an attribute into a logical
952 * cluster number (lcn) of a device using the runlist @rl to map vcns to their
953 * corresponding lcns.
955 * It is up to the caller to serialize access to the runlist @rl.
957 * Since lcns must be >= 0, we use negative return codes with special meaning:
959 * Return code Meaning / Description
960 * ==================================================
961 * LCN_HOLE Hole / not allocated on disk.
962 * LCN_RL_NOT_MAPPED This is part of the runlist which has not been
963 * inserted into the runlist yet.
964 * LCN_ENOENT There is no such vcn in the attribute.
966 * Locking: - The caller must have locked the runlist (for reading or writing).
967 * - This function does not touch the lock, nor does it modify the
970 LCN
ntfs_rl_vcn_to_lcn(const runlist_element
*rl
, const VCN vcn
)
976 * If rl is NULL, assume that we have found an unmapped runlist. The
977 * caller can then attempt to map it and fail appropriately if
981 return LCN_RL_NOT_MAPPED
;
983 /* Catch out of lower bounds vcn. */
984 if (unlikely(vcn
< rl
[0].vcn
))
987 for (i
= 0; likely(rl
[i
].length
); i
++) {
988 if (unlikely(vcn
< rl
[i
+1].vcn
)) {
989 if (likely(rl
[i
].lcn
>= (LCN
)0))
990 return rl
[i
].lcn
+ (vcn
- rl
[i
].vcn
);
995 * The terminator element is setup to the correct value, i.e. one of
996 * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
998 if (likely(rl
[i
].lcn
< (LCN
)0))
1000 /* Just in case... We could replace this with BUG() some day. */
1007 * ntfs_rl_find_vcn_nolock - find a vcn in a runlist
1008 * @rl: runlist to search
1011 * Find the virtual cluster number @vcn in the runlist @rl and return the
1012 * address of the runlist element containing the @vcn on success.
1014 * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of
1017 * Locking: The runlist must be locked on entry.
1019 runlist_element
*ntfs_rl_find_vcn_nolock(runlist_element
*rl
, const VCN vcn
)
1022 if (unlikely(!rl
|| vcn
< rl
[0].vcn
))
1024 while (likely(rl
->length
)) {
1025 if (unlikely(vcn
< rl
[1].vcn
)) {
1026 if (likely(rl
->lcn
>= LCN_HOLE
))
1032 if (likely(rl
->lcn
== LCN_ENOENT
))
1038 * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
1039 * @n: number for which to get the number of bytes for
1041 * Return the number of bytes required to store @n unambiguously as
1044 * This is used in the context of the mapping pairs array to determine how
1045 * many bytes will be needed in the array to store a given logical cluster
1046 * number (lcn) or a specific run length.
1048 * Return the number of bytes written. This function cannot fail.
1050 static inline int ntfs_get_nr_significant_bytes(const s64 n
)
1060 } while (l
!= 0 && l
!= -1);
1061 j
= (n
>> 8 * (i
- 1)) & 0xff;
1062 /* If the sign bit is wrong, we need an extra byte. */
1063 if ((n
< 0 && j
>= 0) || (n
> 0 && j
< 0))
1069 * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
1070 * @vol: ntfs volume (needed for the ntfs version)
1071 * @rl: locked runlist to determine the size of the mapping pairs of
1072 * @first_vcn: first vcn which to include in the mapping pairs array
1073 * @last_vcn: last vcn which to include in the mapping pairs array
1075 * Walk the locked runlist @rl and calculate the size in bytes of the mapping
1076 * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and
1077 * finishing with vcn @last_vcn.
1079 * A @last_vcn of -1 means end of runlist and in that case the size of the
1080 * mapping pairs array corresponding to the runlist starting at vcn @first_vcn
1081 * and finishing at the end of the runlist is determined.
1083 * This for example allows us to allocate a buffer of the right size when
1084 * building the mapping pairs array.
1086 * If @rl is NULL, just return 1 (for the single terminator byte).
1088 * Return the calculated size in bytes on success. On error, return -errno.
1089 * The following error codes are defined:
1090 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1091 * fully mapped runlists to this function.
1092 * -EIO - The runlist is corrupt.
1094 * Locking: @rl must be locked on entry (either for reading or writing), it
1095 * remains locked throughout, and is left locked upon return.
1097 int ntfs_get_size_for_mapping_pairs(const ntfs_volume
*vol
,
1098 const runlist_element
*rl
, const VCN first_vcn
,
1103 bool the_end
= false;
1105 BUG_ON(first_vcn
< 0);
1106 BUG_ON(last_vcn
< -1);
1107 BUG_ON(last_vcn
>= 0 && first_vcn
> last_vcn
);
1110 BUG_ON(last_vcn
> 0);
1113 /* Skip to runlist element containing @first_vcn. */
1114 while (rl
->length
&& first_vcn
>= rl
[1].vcn
)
1116 if (unlikely((!rl
->length
&& first_vcn
> rl
->vcn
) ||
1117 first_vcn
< rl
->vcn
))
1120 /* Always need the termining zero byte. */
1122 /* Do the first partial run if present. */
1123 if (first_vcn
> rl
->vcn
) {
1124 s64 delta
, length
= rl
->length
;
1126 /* We know rl->length != 0 already. */
1127 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1130 * If @stop_vcn is given and finishes inside this run, cap the
1133 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1134 s64 s1
= last_vcn
+ 1;
1135 if (unlikely(rl
[1].vcn
> s1
))
1136 length
= s1
- rl
->vcn
;
1139 delta
= first_vcn
- rl
->vcn
;
1140 /* Header byte + length. */
1141 rls
+= 1 + ntfs_get_nr_significant_bytes(length
- delta
);
1143 * If the logical cluster number (lcn) denotes a hole and we
1144 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1145 * zero space. On earlier NTFS versions we just store the lcn.
1146 * Note: this assumes that on NTFS 1.2-, holes are stored with
1147 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1149 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1151 if (likely(rl
->lcn
>= 0))
1153 /* Change in lcn. */
1154 rls
+= ntfs_get_nr_significant_bytes(prev_lcn
);
1156 /* Go to next runlist element. */
1159 /* Do the full runs. */
1160 for (; rl
->length
&& !the_end
; rl
++) {
1161 s64 length
= rl
->length
;
1163 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1166 * If @stop_vcn is given and finishes inside this run, cap the
1169 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1170 s64 s1
= last_vcn
+ 1;
1171 if (unlikely(rl
[1].vcn
> s1
))
1172 length
= s1
- rl
->vcn
;
1175 /* Header byte + length. */
1176 rls
+= 1 + ntfs_get_nr_significant_bytes(length
);
1178 * If the logical cluster number (lcn) denotes a hole and we
1179 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1180 * zero space. On earlier NTFS versions we just store the lcn.
1181 * Note: this assumes that on NTFS 1.2-, holes are stored with
1182 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1184 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1185 /* Change in lcn. */
1186 rls
+= ntfs_get_nr_significant_bytes(rl
->lcn
-
1193 if (rl
->lcn
== LCN_RL_NOT_MAPPED
)
1201 * ntfs_write_significant_bytes - write the significant bytes of a number
1202 * @dst: destination buffer to write to
1203 * @dst_max: pointer to last byte of destination buffer for bounds checking
1204 * @n: number whose significant bytes to write
1206 * Store in @dst, the minimum bytes of the number @n which are required to
1207 * identify @n unambiguously as a signed number, taking care not to exceed
1208 * @dest_max, the maximum position within @dst to which we are allowed to
1211 * This is used when building the mapping pairs array of a runlist to compress
1212 * a given logical cluster number (lcn) or a specific run length to the minumum
1215 * Return the number of bytes written on success. On error, i.e. the
1216 * destination buffer @dst is too small, return -ENOSPC.
1218 static inline int ntfs_write_significant_bytes(s8
*dst
, const s8
*dst_max
,
1227 if (unlikely(dst
> dst_max
))
1229 *dst
++ = l
& 0xffll
;
1232 } while (l
!= 0 && l
!= -1);
1233 j
= (n
>> 8 * (i
- 1)) & 0xff;
1234 /* If the sign bit is wrong, we need an extra byte. */
1235 if (n
< 0 && j
>= 0) {
1236 if (unlikely(dst
> dst_max
))
1240 } else if (n
> 0 && j
< 0) {
1241 if (unlikely(dst
> dst_max
))
1252 * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
1253 * @vol: ntfs volume (needed for the ntfs version)
1254 * @dst: destination buffer to which to write the mapping pairs array
1255 * @dst_len: size of destination buffer @dst in bytes
1256 * @rl: locked runlist for which to build the mapping pairs array
1257 * @first_vcn: first vcn which to include in the mapping pairs array
1258 * @last_vcn: last vcn which to include in the mapping pairs array
1259 * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC
1261 * Create the mapping pairs array from the locked runlist @rl, starting at vcn
1262 * @first_vcn and finishing with vcn @last_vcn and save the array in @dst.
1263 * @dst_len is the size of @dst in bytes and it should be at least equal to the
1264 * value obtained by calling ntfs_get_size_for_mapping_pairs().
1266 * A @last_vcn of -1 means end of runlist and in that case the mapping pairs
1267 * array corresponding to the runlist starting at vcn @first_vcn and finishing
1268 * at the end of the runlist is created.
1270 * If @rl is NULL, just write a single terminator byte to @dst.
1272 * On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
1273 * the first vcn outside the destination buffer. Note that on error, @dst has
1274 * been filled with all the mapping pairs that will fit, thus it can be treated
1275 * as partial success, in that a new attribute extent needs to be created or
1276 * the next extent has to be used and the mapping pairs build has to be
1277 * continued with @first_vcn set to *@stop_vcn.
1279 * Return 0 on success and -errno on error. The following error codes are
1281 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1282 * fully mapped runlists to this function.
1283 * -EIO - The runlist is corrupt.
1284 * -ENOSPC - The destination buffer is too small.
1286 * Locking: @rl must be locked on entry (either for reading or writing), it
1287 * remains locked throughout, and is left locked upon return.
1289 int ntfs_mapping_pairs_build(const ntfs_volume
*vol
, s8
*dst
,
1290 const int dst_len
, const runlist_element
*rl
,
1291 const VCN first_vcn
, const VCN last_vcn
, VCN
*const stop_vcn
)
1294 s8
*dst_max
, *dst_next
;
1296 bool the_end
= false;
1297 s8 len_len
, lcn_len
;
1299 BUG_ON(first_vcn
< 0);
1300 BUG_ON(last_vcn
< -1);
1301 BUG_ON(last_vcn
>= 0 && first_vcn
> last_vcn
);
1302 BUG_ON(dst_len
< 1);
1305 BUG_ON(last_vcn
> 0);
1308 /* Terminator byte. */
1312 /* Skip to runlist element containing @first_vcn. */
1313 while (rl
->length
&& first_vcn
>= rl
[1].vcn
)
1315 if (unlikely((!rl
->length
&& first_vcn
> rl
->vcn
) ||
1316 first_vcn
< rl
->vcn
))
1319 * @dst_max is used for bounds checking in
1320 * ntfs_write_significant_bytes().
1322 dst_max
= dst
+ dst_len
- 1;
1324 /* Do the first partial run if present. */
1325 if (first_vcn
> rl
->vcn
) {
1326 s64 delta
, length
= rl
->length
;
1328 /* We know rl->length != 0 already. */
1329 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1332 * If @stop_vcn is given and finishes inside this run, cap the
1335 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1336 s64 s1
= last_vcn
+ 1;
1337 if (unlikely(rl
[1].vcn
> s1
))
1338 length
= s1
- rl
->vcn
;
1341 delta
= first_vcn
- rl
->vcn
;
1343 len_len
= ntfs_write_significant_bytes(dst
+ 1, dst_max
,
1345 if (unlikely(len_len
< 0))
1347 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1349 if (likely(rl
->lcn
>= 0))
1351 /* Write change in lcn. */
1352 lcn_len
= ntfs_write_significant_bytes(dst
+ 1 +
1353 len_len
, dst_max
, prev_lcn
);
1354 if (unlikely(lcn_len
< 0))
1358 dst_next
= dst
+ len_len
+ lcn_len
+ 1;
1359 if (unlikely(dst_next
> dst_max
))
1361 /* Update header byte. */
1362 *dst
= lcn_len
<< 4 | len_len
;
1363 /* Position at next mapping pairs array element. */
1365 /* Go to next runlist element. */
1368 /* Do the full runs. */
1369 for (; rl
->length
&& !the_end
; rl
++) {
1370 s64 length
= rl
->length
;
1372 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1375 * If @stop_vcn is given and finishes inside this run, cap the
1378 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1379 s64 s1
= last_vcn
+ 1;
1380 if (unlikely(rl
[1].vcn
> s1
))
1381 length
= s1
- rl
->vcn
;
1385 len_len
= ntfs_write_significant_bytes(dst
+ 1, dst_max
,
1387 if (unlikely(len_len
< 0))
1389 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1390 /* Write change in lcn. */
1391 lcn_len
= ntfs_write_significant_bytes(dst
+ 1 +
1392 len_len
, dst_max
, rl
->lcn
- prev_lcn
);
1393 if (unlikely(lcn_len
< 0))
1398 dst_next
= dst
+ len_len
+ lcn_len
+ 1;
1399 if (unlikely(dst_next
> dst_max
))
1401 /* Update header byte. */
1402 *dst
= lcn_len
<< 4 | len_len
;
1403 /* Position at next mapping pairs array element. */
1411 *stop_vcn
= rl
->vcn
;
1412 /* Add terminator byte. */
1416 if (rl
->lcn
== LCN_RL_NOT_MAPPED
)
1424 * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn
1425 * @vol: ntfs volume (needed for error output)
1426 * @runlist: runlist to truncate
1427 * @new_length: the new length of the runlist in VCNs
1429 * Truncate the runlist described by @runlist as well as the memory buffer
1430 * holding the runlist elements to a length of @new_length VCNs.
1432 * If @new_length lies within the runlist, the runlist elements with VCNs of
1433 * @new_length and above are discarded. As a special case if @new_length is
1434 * zero, the runlist is discarded and set to NULL.
1436 * If @new_length lies beyond the runlist, a sparse runlist element is added to
1437 * the end of the runlist @runlist or if the last runlist element is a sparse
1438 * one already, this is extended.
1440 * Note, no checking is done for unmapped runlist elements. It is assumed that
1441 * the caller has mapped any elements that need to be mapped already.
1443 * Return 0 on success and -errno on error.
1445 * Locking: The caller must hold @runlist->lock for writing.
1447 int ntfs_rl_truncate_nolock(const ntfs_volume
*vol
, runlist
*const runlist
,
1448 const s64 new_length
)
1450 runlist_element
*rl
;
1453 ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length
);
1455 BUG_ON(new_length
< 0);
1458 ntfs_debug("Freeing runlist.");
1464 if (unlikely(!rl
)) {
1466 * Create a runlist consisting of a sparse runlist element of
1467 * length @new_length followed by a terminator runlist element.
1469 rl
= ntfs_malloc_nofs(PAGE_SIZE
);
1470 if (unlikely(!rl
)) {
1471 ntfs_error(vol
->sb
, "Not enough memory to allocate "
1472 "runlist element buffer.");
1476 rl
[1].length
= rl
->vcn
= 0;
1478 rl
[1].vcn
= rl
->length
= new_length
;
1479 rl
[1].lcn
= LCN_ENOENT
;
1482 BUG_ON(new_length
< rl
->vcn
);
1483 /* Find @new_length in the runlist. */
1484 while (likely(rl
->length
&& new_length
>= rl
[1].vcn
))
1487 * If not at the end of the runlist we need to shrink it.
1488 * If at the end of the runlist we need to expand it.
1491 runlist_element
*trl
;
1494 ntfs_debug("Shrinking runlist.");
1495 /* Determine the runlist size. */
1497 while (likely(trl
->length
))
1499 old_size
= trl
- runlist
->rl
+ 1;
1500 /* Truncate the run. */
1501 rl
->length
= new_length
- rl
->vcn
;
1503 * If a run was partially truncated, make the following runlist
1504 * element a terminator.
1511 rl
->vcn
= new_length
;
1514 rl
->lcn
= LCN_ENOENT
;
1515 /* Reallocate memory if necessary. */
1517 int new_size
= rl
- runlist
->rl
+ 1;
1518 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
, new_size
);
1520 ntfs_warning(vol
->sb
, "Failed to shrink "
1521 "runlist buffer. This just "
1522 "wastes a bit of memory "
1523 "temporarily so we ignore it "
1524 "and return success.");
1528 } else if (likely(/* !rl->length && */ new_length
> rl
->vcn
)) {
1529 ntfs_debug("Expanding runlist.");
1531 * If there is a previous runlist element and it is a sparse
1532 * one, extend it. Otherwise need to add a new, sparse runlist
1535 if ((rl
> runlist
->rl
) && ((rl
- 1)->lcn
== LCN_HOLE
))
1536 (rl
- 1)->length
= new_length
- (rl
- 1)->vcn
;
1538 /* Determine the runlist size. */
1539 old_size
= rl
- runlist
->rl
+ 1;
1540 /* Reallocate memory if necessary. */
1541 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
,
1544 ntfs_error(vol
->sb
, "Failed to expand runlist "
1545 "buffer, aborting.");
1550 * Set @rl to the same runlist element in the new
1551 * runlist as before in the old runlist.
1554 /* Add a new, sparse runlist element. */
1556 rl
->length
= new_length
- rl
->vcn
;
1557 /* Add a new terminator runlist element. */
1561 rl
->vcn
= new_length
;
1562 rl
->lcn
= LCN_ENOENT
;
1563 } else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ {
1564 /* Runlist already has same size as requested. */
1565 rl
->lcn
= LCN_ENOENT
;
1567 ntfs_debug("Done.");
1572 * ntfs_rl_punch_nolock - punch a hole into a runlist
1573 * @vol: ntfs volume (needed for error output)
1574 * @runlist: runlist to punch a hole into
1575 * @start: starting VCN of the hole to be created
1576 * @length: size of the hole to be created in units of clusters
1578 * Punch a hole into the runlist @runlist starting at VCN @start and of size
1581 * Return 0 on success and -errno on error, in which case @runlist has not been
1584 * If @start and/or @start + @length are outside the runlist return error code
1587 * If the runlist contains unmapped or error elements between @start and @start
1588 * + @length return error code -EINVAL.
1590 * Locking: The caller must hold @runlist->lock for writing.
1592 int ntfs_rl_punch_nolock(const ntfs_volume
*vol
, runlist
*const runlist
,
1593 const VCN start
, const s64 length
)
1595 const VCN end
= start
+ length
;
1597 runlist_element
*rl
, *rl_end
, *rl_real_end
, *trl
;
1599 bool lcn_fixup
= false;
1601 ntfs_debug("Entering for start 0x%llx, length 0x%llx.",
1602 (long long)start
, (long long)length
);
1608 if (unlikely(!rl
)) {
1609 if (likely(!start
&& !length
))
1613 /* Find @start in the runlist. */
1614 while (likely(rl
->length
&& start
>= rl
[1].vcn
))
1617 /* Find @end in the runlist. */
1618 while (likely(rl_end
->length
&& end
>= rl_end
[1].vcn
)) {
1619 /* Verify there are no unmapped or error elements. */
1620 if (unlikely(rl_end
->lcn
< LCN_HOLE
))
1624 /* Check the last element. */
1625 if (unlikely(rl_end
->length
&& rl_end
->lcn
< LCN_HOLE
))
1627 /* This covers @start being out of bounds, too. */
1628 if (!rl_end
->length
&& end
> rl_end
->vcn
)
1634 rl_real_end
= rl_end
;
1635 /* Determine the runlist size. */
1636 while (likely(rl_real_end
->length
))
1638 old_size
= rl_real_end
- runlist
->rl
+ 1;
1639 /* If @start is in a hole simply extend the hole. */
1640 if (rl
->lcn
== LCN_HOLE
) {
1642 * If both @start and @end are in the same sparse run, we are
1645 if (end
<= rl
[1].vcn
) {
1646 ntfs_debug("Done (requested hole is already sparse).");
1650 /* Extend the hole. */
1651 rl
->length
= end
- rl
->vcn
;
1652 /* If @end is in a hole, merge it with the current one. */
1653 if (rl_end
->lcn
== LCN_HOLE
) {
1655 rl
->length
= rl_end
->vcn
- rl
->vcn
;
1657 /* We have done the hole. Now deal with the remaining tail. */
1659 /* Cut out all runlist elements up to @end. */
1661 memmove(rl
, rl_end
, (rl_real_end
- rl_end
+ 1) *
1663 /* Adjust the beginning of the tail if necessary. */
1664 if (end
> rl
->vcn
) {
1665 delta
= end
- rl
->vcn
;
1667 rl
->length
-= delta
;
1668 /* Only adjust the lcn if it is real. */
1673 /* Reallocate memory if the allocation changed. */
1675 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
,
1676 old_size
- (rl_end
- rl
));
1678 ntfs_warning(vol
->sb
, "Failed to shrink "
1679 "runlist buffer. This just "
1680 "wastes a bit of memory "
1681 "temporarily so we ignore it "
1682 "and return success.");
1686 ntfs_debug("Done (extend hole).");
1690 * If @start is at the beginning of a run things are easier as there is
1691 * no need to split the first run.
1693 if (start
== rl
->vcn
) {
1695 * @start is at the beginning of a run.
1697 * If the previous run is sparse, extend its hole.
1699 * If @end is not in the same run, switch the run to be sparse
1700 * and extend the newly created hole.
1702 * Thus both of these cases reduce the problem to the above
1703 * case of "@start is in a hole".
1705 if (rl
> runlist
->rl
&& (rl
- 1)->lcn
== LCN_HOLE
) {
1709 if (end
>= rl
[1].vcn
) {
1714 * The final case is when @end is in the same run as @start.
1715 * For this need to split the run into two. One run for the
1716 * sparse region between the beginning of the old run, i.e.
1717 * @start, and @end and one for the remaining non-sparse
1718 * region, i.e. between @end and the end of the old run.
1720 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 1);
1724 if (runlist
->rl
!= trl
) {
1725 rl
= trl
+ (rl
- runlist
->rl
);
1726 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1727 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1731 /* Shift all the runs up by one. */
1732 memmove(rl
+ 1, rl
, (rl_real_end
- rl
+ 1) * sizeof(*rl
));
1733 /* Finally, setup the two split runs. */
1735 rl
->length
= length
;
1738 /* Only adjust the lcn if it is real. */
1739 if (rl
->lcn
>= 0 || lcn_fixup
)
1741 rl
->length
-= length
;
1742 ntfs_debug("Done (split one).");
1746 * @start is neither in a hole nor at the beginning of a run.
1748 * If @end is in a hole, things are easier as simply truncating the run
1749 * @start is in to end at @start - 1, deleting all runs after that up
1750 * to @end, and finally extending the beginning of the run @end is in
1751 * to be @start is all that is needed.
1753 if (rl_end
->lcn
== LCN_HOLE
) {
1754 /* Truncate the run containing @start. */
1755 rl
->length
= start
- rl
->vcn
;
1757 /* Cut out all runlist elements up to @end. */
1759 memmove(rl
, rl_end
, (rl_real_end
- rl_end
+ 1) *
1761 /* Extend the beginning of the run @end is in to be @start. */
1763 rl
->length
= rl
[1].vcn
- start
;
1764 goto shrink_allocation
;
1767 * If @end is not in a hole there are still two cases to distinguish.
1768 * Either @end is or is not in the same run as @start.
1770 * The second case is easier as it can be reduced to an already solved
1771 * problem by truncating the run @start is in to end at @start - 1.
1772 * Then, if @end is in the next run need to split the run into a sparse
1773 * run followed by a non-sparse run (already covered above) and if @end
1774 * is not in the next run switching it to be sparse, again reduces the
1775 * problem to the already covered case of "@start is in a hole".
1777 if (end
>= rl
[1].vcn
) {
1779 * If @end is not in the next run, reduce the problem to the
1780 * case of "@start is in a hole".
1782 if (rl
[1].length
&& end
>= rl
[2].vcn
) {
1783 /* Truncate the run containing @start. */
1784 rl
->length
= start
- rl
->vcn
;
1790 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 1);
1794 if (runlist
->rl
!= trl
) {
1795 rl
= trl
+ (rl
- runlist
->rl
);
1796 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1797 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1800 /* Truncate the run containing @start. */
1801 rl
->length
= start
- rl
->vcn
;
1804 * @end is in the next run, reduce the problem to the case
1805 * where "@start is at the beginning of a run and @end is in
1806 * the same run as @start".
1808 delta
= rl
->vcn
- start
;
1812 /* Need this in case the lcn just became negative. */
1815 rl
->length
+= delta
;
1819 * The first case from above, i.e. @end is in the same run as @start.
1820 * We need to split the run into three. One run for the non-sparse
1821 * region between the beginning of the old run and @start, one for the
1822 * sparse region between @start and @end, and one for the remaining
1823 * non-sparse region, i.e. between @end and the end of the old run.
1825 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 2);
1829 if (runlist
->rl
!= trl
) {
1830 rl
= trl
+ (rl
- runlist
->rl
);
1831 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1832 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1835 /* Shift all the runs up by two. */
1836 memmove(rl
+ 2, rl
, (rl_real_end
- rl
+ 1) * sizeof(*rl
));
1837 /* Finally, setup the three split runs. */
1838 rl
->length
= start
- rl
->vcn
;
1842 rl
->length
= length
;
1844 delta
= end
- rl
->vcn
;
1847 rl
->length
-= delta
;
1848 ntfs_debug("Done (split both).");
1851 ntfs_error(vol
->sb
, "Not enough memory to extend runlist buffer.");
1855 #endif /* NTFS_RW */