]>
git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - fs/ntfs/runlist.c
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 /* 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
))
640 ntfs_debug("dfinal = %i, dend = %i", dfinal
, dend
);
641 ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart
, sfinal
, send
);
642 ntfs_debug("start = %i, finish = %i", start
, finish
);
643 ntfs_debug("ds = %i, ss = %i, dins = %i", ds
, ss
, dins
);
647 drl
= ntfs_rl_replace(drl
, ds
, srl
+ sstart
, ss
, dins
);
649 drl
= ntfs_rl_insert(drl
, ds
, srl
+ sstart
, ss
, dins
);
652 drl
= ntfs_rl_append(drl
, ds
, srl
+ sstart
, ss
, dins
);
654 drl
= ntfs_rl_split(drl
, ds
, srl
+ sstart
, ss
, dins
);
657 ntfs_error(NULL
, "Merge failed.");
662 ntfs_debug("Triggering marker code.");
663 for (ds
= dend
; drl
[ds
].length
; ds
++)
665 /* We only need to care if @srl ended after @drl. */
666 if (drl
[ds
].vcn
<= marker_vcn
) {
669 if (drl
[ds
].vcn
== marker_vcn
) {
670 ntfs_debug("Old marker = 0x%llx, replacing "
674 drl
[ds
].lcn
= LCN_ENOENT
;
678 * We need to create an unmapped runlist element in
679 * @drl or extend an existing one before adding the
682 if (drl
[ds
].lcn
== LCN_ENOENT
) {
686 if (drl
[ds
].lcn
!= LCN_RL_NOT_MAPPED
) {
687 /* Add an unmapped runlist element. */
689 drl
= ntfs_rl_realloc_nofail(drl
, ds
,
694 /* Need to set vcn if it isn't set already. */
696 drl
[ds
].vcn
= drl
[ds
- 1].vcn
+
698 drl
[ds
].lcn
= LCN_RL_NOT_MAPPED
;
699 /* We now used up a slot. */
702 drl
[ds
].length
= marker_vcn
- drl
[ds
].vcn
;
703 /* Finally add the ENOENT terminator. */
706 drl
= ntfs_rl_realloc_nofail(drl
, ds
, ds
+ 1);
707 drl
[ds
].vcn
= marker_vcn
;
708 drl
[ds
].lcn
= LCN_ENOENT
;
709 drl
[ds
].length
= (s64
)0;
715 /* The merge was completed successfully. */
716 ntfs_debug("Merged runlist:");
717 ntfs_debug_dump_runlist(drl
);
722 * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist
723 * @vol: ntfs volume on which the attribute resides
724 * @attr: attribute record whose mapping pairs array to decompress
725 * @old_rl: optional runlist in which to insert @attr's runlist
727 * It is up to the caller to serialize access to the runlist @old_rl.
729 * Decompress the attribute @attr's mapping pairs array into a runlist. On
730 * success, return the decompressed runlist.
732 * If @old_rl is not NULL, decompressed runlist is inserted into the
733 * appropriate place in @old_rl and the resultant, combined runlist is
734 * returned. The original @old_rl is deallocated.
736 * On error, return -errno. @old_rl is left unmodified in that case.
738 * The following error codes are defined:
739 * -ENOMEM - Not enough memory to allocate runlist array.
740 * -EIO - Corrupt runlist.
741 * -EINVAL - Invalid parameters were passed in.
742 * -ERANGE - The two runlists overlap.
744 * FIXME: For now we take the conceptionally simplest approach of creating the
745 * new runlist disregarding the already existing one and then splicing the
746 * two into one, if that is possible (we check for overlap and discard the new
747 * runlist if overlap present before returning ERR_PTR(-ERANGE)).
749 runlist_element
*ntfs_mapping_pairs_decompress(const ntfs_volume
*vol
,
750 const ATTR_RECORD
*attr
, runlist_element
*old_rl
)
752 VCN vcn
; /* Current vcn. */
753 LCN lcn
; /* Current lcn. */
754 s64 deltaxcn
; /* Change in [vl]cn. */
755 runlist_element
*rl
; /* The output runlist. */
756 u8
*buf
; /* Current position in mapping pairs array. */
757 u8
*attr_end
; /* End of attribute. */
758 int rlsize
; /* Size of runlist buffer. */
759 u16 rlpos
; /* Current runlist position in units of
761 u8 b
; /* Current byte offset in buf. */
764 /* Make sure attr exists and is non-resident. */
765 if (!attr
|| !attr
->non_resident
|| sle64_to_cpu(
766 attr
->data
.non_resident
.lowest_vcn
) < (VCN
)0) {
767 ntfs_error(vol
->sb
, "Invalid arguments.");
768 return ERR_PTR(-EINVAL
);
771 /* Start at vcn = lowest_vcn and lcn 0. */
772 vcn
= sle64_to_cpu(attr
->data
.non_resident
.lowest_vcn
);
774 /* Get start of the mapping pairs array. */
775 buf
= (u8
*)attr
+ le16_to_cpu(
776 attr
->data
.non_resident
.mapping_pairs_offset
);
777 attr_end
= (u8
*)attr
+ le32_to_cpu(attr
->length
);
778 if (unlikely(buf
< (u8
*)attr
|| buf
> attr_end
)) {
779 ntfs_error(vol
->sb
, "Corrupt attribute.");
780 return ERR_PTR(-EIO
);
782 /* If the mapping pairs array is valid but empty, nothing to do. */
785 /* Current position in runlist array. */
787 /* Allocate first page and set current runlist size to one page. */
788 rl
= ntfs_malloc_nofs(rlsize
= PAGE_SIZE
);
790 return ERR_PTR(-ENOMEM
);
791 /* Insert unmapped starting element if necessary. */
794 rl
->lcn
= LCN_RL_NOT_MAPPED
;
798 while (buf
< attr_end
&& *buf
) {
800 * Allocate more memory if needed, including space for the
801 * not-mapped and terminator elements. ntfs_malloc_nofs()
802 * operates on whole pages only.
804 if (((rlpos
+ 3) * sizeof(*old_rl
)) > rlsize
) {
805 runlist_element
*rl2
;
807 rl2
= ntfs_malloc_nofs(rlsize
+ (int)PAGE_SIZE
);
808 if (unlikely(!rl2
)) {
810 return ERR_PTR(-ENOMEM
);
812 memcpy(rl2
, rl
, rlsize
);
817 /* Enter the current vcn into the current runlist element. */
820 * Get the change in vcn, i.e. the run length in clusters.
821 * Doing it this way ensures that we signextend negative values.
822 * A negative run length doesn't make any sense, but hey, I
823 * didn't make up the NTFS specs and Windows NT4 treats the run
824 * length as a signed value so that's how it is...
828 if (unlikely(buf
+ b
> attr_end
))
830 for (deltaxcn
= (s8
)buf
[b
--]; b
; b
--)
831 deltaxcn
= (deltaxcn
<< 8) + buf
[b
];
832 } else { /* The length entry is compulsory. */
833 ntfs_error(vol
->sb
, "Missing length entry in mapping "
838 * Assume a negative length to indicate data corruption and
839 * hence clean-up and return NULL.
841 if (unlikely(deltaxcn
< 0)) {
842 ntfs_error(vol
->sb
, "Invalid length in mapping pairs "
847 * Enter the current run length into the current runlist
850 rl
[rlpos
].length
= deltaxcn
;
851 /* Increment the current vcn by the current run length. */
854 * There might be no lcn change at all, as is the case for
855 * sparse clusters on NTFS 3.0+, in which case we set the lcn
859 rl
[rlpos
].lcn
= LCN_HOLE
;
861 /* Get the lcn change which really can be negative. */
863 b
= b2
+ ((*buf
>> 4) & 0xf);
864 if (buf
+ b
> attr_end
)
866 for (deltaxcn
= (s8
)buf
[b
--]; b
> b2
; b
--)
867 deltaxcn
= (deltaxcn
<< 8) + buf
[b
];
868 /* Change the current lcn to its new value. */
872 * On NTFS 1.2-, apparently can have lcn == -1 to
873 * indicate a hole. But we haven't verified ourselves
874 * whether it is really the lcn or the deltaxcn that is
875 * -1. So if either is found give us a message so we
876 * can investigate it further!
878 if (vol
->major_ver
< 3) {
879 if (unlikely(deltaxcn
== (LCN
)-1))
880 ntfs_error(vol
->sb
, "lcn delta == -1");
881 if (unlikely(lcn
== (LCN
)-1))
882 ntfs_error(vol
->sb
, "lcn == -1");
885 /* Check lcn is not below -1. */
886 if (unlikely(lcn
< (LCN
)-1)) {
887 ntfs_error(vol
->sb
, "Invalid LCN < -1 in "
888 "mapping pairs array.");
891 /* Enter the current lcn into the runlist element. */
894 /* Get to the next runlist element. */
896 /* Increment the buffer position to the next mapping pair. */
897 buf
+= (*buf
& 0xf) + ((*buf
>> 4) & 0xf) + 1;
899 if (unlikely(buf
>= attr_end
))
902 * If there is a highest_vcn specified, it must be equal to the final
903 * vcn in the runlist - 1, or something has gone badly wrong.
905 deltaxcn
= sle64_to_cpu(attr
->data
.non_resident
.highest_vcn
);
906 if (unlikely(deltaxcn
&& vcn
- 1 != deltaxcn
)) {
908 ntfs_error(vol
->sb
, "Corrupt mapping pairs array in "
909 "non-resident attribute.");
912 /* Setup not mapped runlist element if this is the base extent. */
913 if (!attr
->data
.non_resident
.lowest_vcn
) {
916 max_cluster
= ((sle64_to_cpu(
917 attr
->data
.non_resident
.allocated_size
) +
918 vol
->cluster_size
- 1) >>
919 vol
->cluster_size_bits
) - 1;
921 * A highest_vcn of zero means this is a single extent
922 * attribute so simply terminate the runlist with LCN_ENOENT).
926 * If there is a difference between the highest_vcn and
927 * the highest cluster, the runlist is either corrupt
928 * or, more likely, there are more extents following
931 if (deltaxcn
< max_cluster
) {
932 ntfs_debug("More extents to follow; deltaxcn "
933 "= 0x%llx, max_cluster = "
935 (unsigned long long)deltaxcn
,
939 vcn
+= rl
[rlpos
].length
= max_cluster
-
941 rl
[rlpos
].lcn
= LCN_RL_NOT_MAPPED
;
943 } else if (unlikely(deltaxcn
> max_cluster
)) {
944 ntfs_error(vol
->sb
, "Corrupt attribute. "
945 "deltaxcn = 0x%llx, "
946 "max_cluster = 0x%llx",
947 (unsigned long long)deltaxcn
,
953 rl
[rlpos
].lcn
= LCN_ENOENT
;
954 } else /* Not the base extent. There may be more extents to follow. */
955 rl
[rlpos
].lcn
= LCN_RL_NOT_MAPPED
;
957 /* Setup terminating runlist element. */
959 rl
[rlpos
].length
= (s64
)0;
960 /* If no existing runlist was specified, we are done. */
962 ntfs_debug("Mapping pairs array successfully decompressed:");
963 ntfs_debug_dump_runlist(rl
);
966 /* Now combine the new and old runlists checking for overlaps. */
967 old_rl
= ntfs_runlists_merge(old_rl
, rl
);
968 if (likely(!IS_ERR(old_rl
)))
971 ntfs_error(vol
->sb
, "Failed to merge runlists.");
974 ntfs_error(vol
->sb
, "Corrupt attribute.");
977 return ERR_PTR(-EIO
);
981 * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist
982 * @rl: runlist to use for conversion
983 * @vcn: vcn to convert
985 * Convert the virtual cluster number @vcn of an attribute into a logical
986 * cluster number (lcn) of a device using the runlist @rl to map vcns to their
987 * corresponding lcns.
989 * It is up to the caller to serialize access to the runlist @rl.
991 * Since lcns must be >= 0, we use negative return codes with special meaning:
993 * Return code Meaning / Description
994 * ==================================================
995 * LCN_HOLE Hole / not allocated on disk.
996 * LCN_RL_NOT_MAPPED This is part of the runlist which has not been
997 * inserted into the runlist yet.
998 * LCN_ENOENT There is no such vcn in the attribute.
1000 * Locking: - The caller must have locked the runlist (for reading or writing).
1001 * - This function does not touch the lock, nor does it modify the
1004 LCN
ntfs_rl_vcn_to_lcn(const runlist_element
*rl
, const VCN vcn
)
1010 * If rl is NULL, assume that we have found an unmapped runlist. The
1011 * caller can then attempt to map it and fail appropriately if
1015 return LCN_RL_NOT_MAPPED
;
1017 /* Catch out of lower bounds vcn. */
1018 if (unlikely(vcn
< rl
[0].vcn
))
1021 for (i
= 0; likely(rl
[i
].length
); i
++) {
1022 if (unlikely(vcn
< rl
[i
+1].vcn
)) {
1023 if (likely(rl
[i
].lcn
>= (LCN
)0))
1024 return rl
[i
].lcn
+ (vcn
- rl
[i
].vcn
);
1029 * The terminator element is setup to the correct value, i.e. one of
1030 * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT.
1032 if (likely(rl
[i
].lcn
< (LCN
)0))
1034 /* Just in case... We could replace this with BUG() some day. */
1041 * ntfs_rl_find_vcn_nolock - find a vcn in a runlist
1042 * @rl: runlist to search
1045 * Find the virtual cluster number @vcn in the runlist @rl and return the
1046 * address of the runlist element containing the @vcn on success.
1048 * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of
1051 * Locking: The runlist must be locked on entry.
1053 runlist_element
*ntfs_rl_find_vcn_nolock(runlist_element
*rl
, const VCN vcn
)
1056 if (unlikely(!rl
|| vcn
< rl
[0].vcn
))
1058 while (likely(rl
->length
)) {
1059 if (unlikely(vcn
< rl
[1].vcn
)) {
1060 if (likely(rl
->lcn
>= LCN_HOLE
))
1066 if (likely(rl
->lcn
== LCN_ENOENT
))
1072 * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number
1073 * @n: number for which to get the number of bytes for
1075 * Return the number of bytes required to store @n unambiguously as
1078 * This is used in the context of the mapping pairs array to determine how
1079 * many bytes will be needed in the array to store a given logical cluster
1080 * number (lcn) or a specific run length.
1082 * Return the number of bytes written. This function cannot fail.
1084 static inline int ntfs_get_nr_significant_bytes(const s64 n
)
1094 } while (l
!= 0 && l
!= -1);
1095 j
= (n
>> 8 * (i
- 1)) & 0xff;
1096 /* If the sign bit is wrong, we need an extra byte. */
1097 if ((n
< 0 && j
>= 0) || (n
> 0 && j
< 0))
1103 * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array
1104 * @vol: ntfs volume (needed for the ntfs version)
1105 * @rl: locked runlist to determine the size of the mapping pairs of
1106 * @first_vcn: first vcn which to include in the mapping pairs array
1107 * @last_vcn: last vcn which to include in the mapping pairs array
1109 * Walk the locked runlist @rl and calculate the size in bytes of the mapping
1110 * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and
1111 * finishing with vcn @last_vcn.
1113 * A @last_vcn of -1 means end of runlist and in that case the size of the
1114 * mapping pairs array corresponding to the runlist starting at vcn @first_vcn
1115 * and finishing at the end of the runlist is determined.
1117 * This for example allows us to allocate a buffer of the right size when
1118 * building the mapping pairs array.
1120 * If @rl is NULL, just return 1 (for the single terminator byte).
1122 * Return the calculated size in bytes on success. On error, return -errno.
1123 * The following error codes are defined:
1124 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1125 * fully mapped runlists to this function.
1126 * -EIO - The runlist is corrupt.
1128 * Locking: @rl must be locked on entry (either for reading or writing), it
1129 * remains locked throughout, and is left locked upon return.
1131 int ntfs_get_size_for_mapping_pairs(const ntfs_volume
*vol
,
1132 const runlist_element
*rl
, const VCN first_vcn
,
1137 bool the_end
= false;
1139 BUG_ON(first_vcn
< 0);
1140 BUG_ON(last_vcn
< -1);
1141 BUG_ON(last_vcn
>= 0 && first_vcn
> last_vcn
);
1144 BUG_ON(last_vcn
> 0);
1147 /* Skip to runlist element containing @first_vcn. */
1148 while (rl
->length
&& first_vcn
>= rl
[1].vcn
)
1150 if (unlikely((!rl
->length
&& first_vcn
> rl
->vcn
) ||
1151 first_vcn
< rl
->vcn
))
1154 /* Always need the termining zero byte. */
1156 /* Do the first partial run if present. */
1157 if (first_vcn
> rl
->vcn
) {
1158 s64 delta
, length
= rl
->length
;
1160 /* We know rl->length != 0 already. */
1161 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1164 * If @stop_vcn is given and finishes inside this run, cap the
1167 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1168 s64 s1
= last_vcn
+ 1;
1169 if (unlikely(rl
[1].vcn
> s1
))
1170 length
= s1
- rl
->vcn
;
1173 delta
= first_vcn
- rl
->vcn
;
1174 /* Header byte + length. */
1175 rls
+= 1 + ntfs_get_nr_significant_bytes(length
- delta
);
1177 * If the logical cluster number (lcn) denotes a hole and we
1178 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1179 * zero space. On earlier NTFS versions we just store the lcn.
1180 * Note: this assumes that on NTFS 1.2-, holes are stored with
1181 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1183 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1185 if (likely(rl
->lcn
>= 0))
1187 /* Change in lcn. */
1188 rls
+= ntfs_get_nr_significant_bytes(prev_lcn
);
1190 /* Go to next runlist element. */
1193 /* Do the full runs. */
1194 for (; rl
->length
&& !the_end
; rl
++) {
1195 s64 length
= rl
->length
;
1197 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1200 * If @stop_vcn is given and finishes inside this run, cap the
1203 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1204 s64 s1
= last_vcn
+ 1;
1205 if (unlikely(rl
[1].vcn
> s1
))
1206 length
= s1
- rl
->vcn
;
1209 /* Header byte + length. */
1210 rls
+= 1 + ntfs_get_nr_significant_bytes(length
);
1212 * If the logical cluster number (lcn) denotes a hole and we
1213 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1214 * zero space. On earlier NTFS versions we just store the lcn.
1215 * Note: this assumes that on NTFS 1.2-, holes are stored with
1216 * an lcn of -1 and not a delta_lcn of -1 (unless both are -1).
1218 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1219 /* Change in lcn. */
1220 rls
+= ntfs_get_nr_significant_bytes(rl
->lcn
-
1227 if (rl
->lcn
== LCN_RL_NOT_MAPPED
)
1235 * ntfs_write_significant_bytes - write the significant bytes of a number
1236 * @dst: destination buffer to write to
1237 * @dst_max: pointer to last byte of destination buffer for bounds checking
1238 * @n: number whose significant bytes to write
1240 * Store in @dst, the minimum bytes of the number @n which are required to
1241 * identify @n unambiguously as a signed number, taking care not to exceed
1242 * @dest_max, the maximum position within @dst to which we are allowed to
1245 * This is used when building the mapping pairs array of a runlist to compress
1246 * a given logical cluster number (lcn) or a specific run length to the minumum
1249 * Return the number of bytes written on success. On error, i.e. the
1250 * destination buffer @dst is too small, return -ENOSPC.
1252 static inline int ntfs_write_significant_bytes(s8
*dst
, const s8
*dst_max
,
1261 if (unlikely(dst
> dst_max
))
1263 *dst
++ = l
& 0xffll
;
1266 } while (l
!= 0 && l
!= -1);
1267 j
= (n
>> 8 * (i
- 1)) & 0xff;
1268 /* If the sign bit is wrong, we need an extra byte. */
1269 if (n
< 0 && j
>= 0) {
1270 if (unlikely(dst
> dst_max
))
1274 } else if (n
> 0 && j
< 0) {
1275 if (unlikely(dst
> dst_max
))
1286 * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist
1287 * @vol: ntfs volume (needed for the ntfs version)
1288 * @dst: destination buffer to which to write the mapping pairs array
1289 * @dst_len: size of destination buffer @dst in bytes
1290 * @rl: locked runlist for which to build the mapping pairs array
1291 * @first_vcn: first vcn which to include in the mapping pairs array
1292 * @last_vcn: last vcn which to include in the mapping pairs array
1293 * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC
1295 * Create the mapping pairs array from the locked runlist @rl, starting at vcn
1296 * @first_vcn and finishing with vcn @last_vcn and save the array in @dst.
1297 * @dst_len is the size of @dst in bytes and it should be at least equal to the
1298 * value obtained by calling ntfs_get_size_for_mapping_pairs().
1300 * A @last_vcn of -1 means end of runlist and in that case the mapping pairs
1301 * array corresponding to the runlist starting at vcn @first_vcn and finishing
1302 * at the end of the runlist is created.
1304 * If @rl is NULL, just write a single terminator byte to @dst.
1306 * On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to
1307 * the first vcn outside the destination buffer. Note that on error, @dst has
1308 * been filled with all the mapping pairs that will fit, thus it can be treated
1309 * as partial success, in that a new attribute extent needs to be created or
1310 * the next extent has to be used and the mapping pairs build has to be
1311 * continued with @first_vcn set to *@stop_vcn.
1313 * Return 0 on success and -errno on error. The following error codes are
1315 * -EINVAL - Run list contains unmapped elements. Make sure to only pass
1316 * fully mapped runlists to this function.
1317 * -EIO - The runlist is corrupt.
1318 * -ENOSPC - The destination buffer is too small.
1320 * Locking: @rl must be locked on entry (either for reading or writing), it
1321 * remains locked throughout, and is left locked upon return.
1323 int ntfs_mapping_pairs_build(const ntfs_volume
*vol
, s8
*dst
,
1324 const int dst_len
, const runlist_element
*rl
,
1325 const VCN first_vcn
, const VCN last_vcn
, VCN
*const stop_vcn
)
1328 s8
*dst_max
, *dst_next
;
1330 bool the_end
= false;
1331 s8 len_len
, lcn_len
;
1333 BUG_ON(first_vcn
< 0);
1334 BUG_ON(last_vcn
< -1);
1335 BUG_ON(last_vcn
>= 0 && first_vcn
> last_vcn
);
1336 BUG_ON(dst_len
< 1);
1339 BUG_ON(last_vcn
> 0);
1342 /* Terminator byte. */
1346 /* Skip to runlist element containing @first_vcn. */
1347 while (rl
->length
&& first_vcn
>= rl
[1].vcn
)
1349 if (unlikely((!rl
->length
&& first_vcn
> rl
->vcn
) ||
1350 first_vcn
< rl
->vcn
))
1353 * @dst_max is used for bounds checking in
1354 * ntfs_write_significant_bytes().
1356 dst_max
= dst
+ dst_len
- 1;
1358 /* Do the first partial run if present. */
1359 if (first_vcn
> rl
->vcn
) {
1360 s64 delta
, length
= rl
->length
;
1362 /* We know rl->length != 0 already. */
1363 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1366 * If @stop_vcn is given and finishes inside this run, cap the
1369 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1370 s64 s1
= last_vcn
+ 1;
1371 if (unlikely(rl
[1].vcn
> s1
))
1372 length
= s1
- rl
->vcn
;
1375 delta
= first_vcn
- rl
->vcn
;
1377 len_len
= ntfs_write_significant_bytes(dst
+ 1, dst_max
,
1379 if (unlikely(len_len
< 0))
1382 * If the logical cluster number (lcn) denotes a hole and we
1383 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1384 * zero space. On earlier NTFS versions we just write the lcn
1385 * change. FIXME: Do we need to write the lcn change or just
1386 * the lcn in that case? Not sure as I have never seen this
1387 * case on NT4. - We assume that we just need to write the lcn
1388 * change until someone tells us otherwise... (AIA)
1390 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1392 if (likely(rl
->lcn
>= 0))
1394 /* Write change in lcn. */
1395 lcn_len
= ntfs_write_significant_bytes(dst
+ 1 +
1396 len_len
, dst_max
, prev_lcn
);
1397 if (unlikely(lcn_len
< 0))
1401 dst_next
= dst
+ len_len
+ lcn_len
+ 1;
1402 if (unlikely(dst_next
> dst_max
))
1404 /* Update header byte. */
1405 *dst
= lcn_len
<< 4 | len_len
;
1406 /* Position at next mapping pairs array element. */
1408 /* Go to next runlist element. */
1411 /* Do the full runs. */
1412 for (; rl
->length
&& !the_end
; rl
++) {
1413 s64 length
= rl
->length
;
1415 if (unlikely(length
< 0 || rl
->lcn
< LCN_HOLE
))
1418 * If @stop_vcn is given and finishes inside this run, cap the
1421 if (unlikely(last_vcn
>= 0 && rl
[1].vcn
> last_vcn
)) {
1422 s64 s1
= last_vcn
+ 1;
1423 if (unlikely(rl
[1].vcn
> s1
))
1424 length
= s1
- rl
->vcn
;
1428 len_len
= ntfs_write_significant_bytes(dst
+ 1, dst_max
,
1430 if (unlikely(len_len
< 0))
1433 * If the logical cluster number (lcn) denotes a hole and we
1434 * are on NTFS 3.0+, we don't store it at all, i.e. we need
1435 * zero space. On earlier NTFS versions we just write the lcn
1436 * change. FIXME: Do we need to write the lcn change or just
1437 * the lcn in that case? Not sure as I have never seen this
1438 * case on NT4. - We assume that we just need to write the lcn
1439 * change until someone tells us otherwise... (AIA)
1441 if (likely(rl
->lcn
>= 0 || vol
->major_ver
< 3)) {
1442 /* Write change in lcn. */
1443 lcn_len
= ntfs_write_significant_bytes(dst
+ 1 +
1444 len_len
, dst_max
, rl
->lcn
- prev_lcn
);
1445 if (unlikely(lcn_len
< 0))
1450 dst_next
= dst
+ len_len
+ lcn_len
+ 1;
1451 if (unlikely(dst_next
> dst_max
))
1453 /* Update header byte. */
1454 *dst
= lcn_len
<< 4 | len_len
;
1455 /* Position at next mapping pairs array element. */
1463 *stop_vcn
= rl
->vcn
;
1464 /* Add terminator byte. */
1468 if (rl
->lcn
== LCN_RL_NOT_MAPPED
)
1476 * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn
1477 * @vol: ntfs volume (needed for error output)
1478 * @runlist: runlist to truncate
1479 * @new_length: the new length of the runlist in VCNs
1481 * Truncate the runlist described by @runlist as well as the memory buffer
1482 * holding the runlist elements to a length of @new_length VCNs.
1484 * If @new_length lies within the runlist, the runlist elements with VCNs of
1485 * @new_length and above are discarded. As a special case if @new_length is
1486 * zero, the runlist is discarded and set to NULL.
1488 * If @new_length lies beyond the runlist, a sparse runlist element is added to
1489 * the end of the runlist @runlist or if the last runlist element is a sparse
1490 * one already, this is extended.
1492 * Note, no checking is done for unmapped runlist elements. It is assumed that
1493 * the caller has mapped any elements that need to be mapped already.
1495 * Return 0 on success and -errno on error.
1497 * Locking: The caller must hold @runlist->lock for writing.
1499 int ntfs_rl_truncate_nolock(const ntfs_volume
*vol
, runlist
*const runlist
,
1500 const s64 new_length
)
1502 runlist_element
*rl
;
1505 ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length
);
1507 BUG_ON(new_length
< 0);
1510 ntfs_debug("Freeing runlist.");
1516 if (unlikely(!rl
)) {
1518 * Create a runlist consisting of a sparse runlist element of
1519 * length @new_length followed by a terminator runlist element.
1521 rl
= ntfs_malloc_nofs(PAGE_SIZE
);
1522 if (unlikely(!rl
)) {
1523 ntfs_error(vol
->sb
, "Not enough memory to allocate "
1524 "runlist element buffer.");
1528 rl
[1].length
= rl
->vcn
= 0;
1530 rl
[1].vcn
= rl
->length
= new_length
;
1531 rl
[1].lcn
= LCN_ENOENT
;
1534 BUG_ON(new_length
< rl
->vcn
);
1535 /* Find @new_length in the runlist. */
1536 while (likely(rl
->length
&& new_length
>= rl
[1].vcn
))
1539 * If not at the end of the runlist we need to shrink it.
1540 * If at the end of the runlist we need to expand it.
1543 runlist_element
*trl
;
1546 ntfs_debug("Shrinking runlist.");
1547 /* Determine the runlist size. */
1549 while (likely(trl
->length
))
1551 old_size
= trl
- runlist
->rl
+ 1;
1552 /* Truncate the run. */
1553 rl
->length
= new_length
- rl
->vcn
;
1555 * If a run was partially truncated, make the following runlist
1556 * element a terminator.
1563 rl
->vcn
= new_length
;
1566 rl
->lcn
= LCN_ENOENT
;
1567 /* Reallocate memory if necessary. */
1569 int new_size
= rl
- runlist
->rl
+ 1;
1570 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
, new_size
);
1572 ntfs_warning(vol
->sb
, "Failed to shrink "
1573 "runlist buffer. This just "
1574 "wastes a bit of memory "
1575 "temporarily so we ignore it "
1576 "and return success.");
1580 } else if (likely(/* !rl->length && */ new_length
> rl
->vcn
)) {
1581 ntfs_debug("Expanding runlist.");
1583 * If there is a previous runlist element and it is a sparse
1584 * one, extend it. Otherwise need to add a new, sparse runlist
1587 if ((rl
> runlist
->rl
) && ((rl
- 1)->lcn
== LCN_HOLE
))
1588 (rl
- 1)->length
= new_length
- (rl
- 1)->vcn
;
1590 /* Determine the runlist size. */
1591 old_size
= rl
- runlist
->rl
+ 1;
1592 /* Reallocate memory if necessary. */
1593 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
,
1596 ntfs_error(vol
->sb
, "Failed to expand runlist "
1597 "buffer, aborting.");
1602 * Set @rl to the same runlist element in the new
1603 * runlist as before in the old runlist.
1606 /* Add a new, sparse runlist element. */
1608 rl
->length
= new_length
- rl
->vcn
;
1609 /* Add a new terminator runlist element. */
1613 rl
->vcn
= new_length
;
1614 rl
->lcn
= LCN_ENOENT
;
1615 } else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ {
1616 /* Runlist already has same size as requested. */
1617 rl
->lcn
= LCN_ENOENT
;
1619 ntfs_debug("Done.");
1624 * ntfs_rl_punch_nolock - punch a hole into a runlist
1625 * @vol: ntfs volume (needed for error output)
1626 * @runlist: runlist to punch a hole into
1627 * @start: starting VCN of the hole to be created
1628 * @length: size of the hole to be created in units of clusters
1630 * Punch a hole into the runlist @runlist starting at VCN @start and of size
1633 * Return 0 on success and -errno on error, in which case @runlist has not been
1636 * If @start and/or @start + @length are outside the runlist return error code
1639 * If the runlist contains unmapped or error elements between @start and @start
1640 * + @length return error code -EINVAL.
1642 * Locking: The caller must hold @runlist->lock for writing.
1644 int ntfs_rl_punch_nolock(const ntfs_volume
*vol
, runlist
*const runlist
,
1645 const VCN start
, const s64 length
)
1647 const VCN end
= start
+ length
;
1649 runlist_element
*rl
, *rl_end
, *rl_real_end
, *trl
;
1651 bool lcn_fixup
= false;
1653 ntfs_debug("Entering for start 0x%llx, length 0x%llx.",
1654 (long long)start
, (long long)length
);
1660 if (unlikely(!rl
)) {
1661 if (likely(!start
&& !length
))
1665 /* Find @start in the runlist. */
1666 while (likely(rl
->length
&& start
>= rl
[1].vcn
))
1669 /* Find @end in the runlist. */
1670 while (likely(rl_end
->length
&& end
>= rl_end
[1].vcn
)) {
1671 /* Verify there are no unmapped or error elements. */
1672 if (unlikely(rl_end
->lcn
< LCN_HOLE
))
1676 /* Check the last element. */
1677 if (unlikely(rl_end
->length
&& rl_end
->lcn
< LCN_HOLE
))
1679 /* This covers @start being out of bounds, too. */
1680 if (!rl_end
->length
&& end
> rl_end
->vcn
)
1686 rl_real_end
= rl_end
;
1687 /* Determine the runlist size. */
1688 while (likely(rl_real_end
->length
))
1690 old_size
= rl_real_end
- runlist
->rl
+ 1;
1691 /* If @start is in a hole simply extend the hole. */
1692 if (rl
->lcn
== LCN_HOLE
) {
1694 * If both @start and @end are in the same sparse run, we are
1697 if (end
<= rl
[1].vcn
) {
1698 ntfs_debug("Done (requested hole is already sparse).");
1702 /* Extend the hole. */
1703 rl
->length
= end
- rl
->vcn
;
1704 /* If @end is in a hole, merge it with the current one. */
1705 if (rl_end
->lcn
== LCN_HOLE
) {
1707 rl
->length
= rl_end
->vcn
- rl
->vcn
;
1709 /* We have done the hole. Now deal with the remaining tail. */
1711 /* Cut out all runlist elements up to @end. */
1713 memmove(rl
, rl_end
, (rl_real_end
- rl_end
+ 1) *
1715 /* Adjust the beginning of the tail if necessary. */
1716 if (end
> rl
->vcn
) {
1717 s64 delta
= end
- rl
->vcn
;
1719 rl
->length
-= delta
;
1720 /* Only adjust the lcn if it is real. */
1725 /* Reallocate memory if the allocation changed. */
1727 rl
= ntfs_rl_realloc(runlist
->rl
, old_size
,
1728 old_size
- (rl_end
- rl
));
1730 ntfs_warning(vol
->sb
, "Failed to shrink "
1731 "runlist buffer. This just "
1732 "wastes a bit of memory "
1733 "temporarily so we ignore it "
1734 "and return success.");
1738 ntfs_debug("Done (extend hole).");
1742 * If @start is at the beginning of a run things are easier as there is
1743 * no need to split the first run.
1745 if (start
== rl
->vcn
) {
1747 * @start is at the beginning of a run.
1749 * If the previous run is sparse, extend its hole.
1751 * If @end is not in the same run, switch the run to be sparse
1752 * and extend the newly created hole.
1754 * Thus both of these cases reduce the problem to the above
1755 * case of "@start is in a hole".
1757 if (rl
> runlist
->rl
&& (rl
- 1)->lcn
== LCN_HOLE
) {
1761 if (end
>= rl
[1].vcn
) {
1766 * The final case is when @end is in the same run as @start.
1767 * For this need to split the run into two. One run for the
1768 * sparse region between the beginning of the old run, i.e.
1769 * @start, and @end and one for the remaining non-sparse
1770 * region, i.e. between @end and the end of the old run.
1772 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 1);
1776 if (runlist
->rl
!= trl
) {
1777 rl
= trl
+ (rl
- runlist
->rl
);
1778 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1779 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1783 /* Shift all the runs up by one. */
1784 memmove(rl
+ 1, rl
, (rl_real_end
- rl
+ 1) * sizeof(*rl
));
1785 /* Finally, setup the two split runs. */
1787 rl
->length
= length
;
1790 /* Only adjust the lcn if it is real. */
1791 if (rl
->lcn
>= 0 || lcn_fixup
)
1793 rl
->length
-= length
;
1794 ntfs_debug("Done (split one).");
1798 * @start is neither in a hole nor at the beginning of a run.
1800 * If @end is in a hole, things are easier as simply truncating the run
1801 * @start is in to end at @start - 1, deleting all runs after that up
1802 * to @end, and finally extending the beginning of the run @end is in
1803 * to be @start is all that is needed.
1805 if (rl_end
->lcn
== LCN_HOLE
) {
1806 /* Truncate the run containing @start. */
1807 rl
->length
= start
- rl
->vcn
;
1809 /* Cut out all runlist elements up to @end. */
1811 memmove(rl
, rl_end
, (rl_real_end
- rl_end
+ 1) *
1813 /* Extend the beginning of the run @end is in to be @start. */
1815 rl
->length
= rl
[1].vcn
- start
;
1816 goto shrink_allocation
;
1819 * If @end is not in a hole there are still two cases to distinguish.
1820 * Either @end is or is not in the same run as @start.
1822 * The second case is easier as it can be reduced to an already solved
1823 * problem by truncating the run @start is in to end at @start - 1.
1824 * Then, if @end is in the next run need to split the run into a sparse
1825 * run followed by a non-sparse run (already covered above) and if @end
1826 * is not in the next run switching it to be sparse, again reduces the
1827 * problem to the already covered case of "@start is in a hole".
1829 if (end
>= rl
[1].vcn
) {
1831 * If @end is not in the next run, reduce the problem to the
1832 * case of "@start is in a hole".
1834 if (rl
[1].length
&& end
>= rl
[2].vcn
) {
1835 /* Truncate the run containing @start. */
1836 rl
->length
= start
- rl
->vcn
;
1842 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 1);
1846 if (runlist
->rl
!= trl
) {
1847 rl
= trl
+ (rl
- runlist
->rl
);
1848 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1849 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1852 /* Truncate the run containing @start. */
1853 rl
->length
= start
- rl
->vcn
;
1856 * @end is in the next run, reduce the problem to the case
1857 * where "@start is at the beginning of a run and @end is in
1858 * the same run as @start".
1860 delta
= rl
->vcn
- start
;
1864 /* Need this in case the lcn just became negative. */
1867 rl
->length
+= delta
;
1871 * The first case from above, i.e. @end is in the same run as @start.
1872 * We need to split the run into three. One run for the non-sparse
1873 * region between the beginning of the old run and @start, one for the
1874 * sparse region between @start and @end, and one for the remaining
1875 * non-sparse region, i.e. between @end and the end of the old run.
1877 trl
= ntfs_rl_realloc(runlist
->rl
, old_size
, old_size
+ 2);
1881 if (runlist
->rl
!= trl
) {
1882 rl
= trl
+ (rl
- runlist
->rl
);
1883 rl_end
= trl
+ (rl_end
- runlist
->rl
);
1884 rl_real_end
= trl
+ (rl_real_end
- runlist
->rl
);
1887 /* Shift all the runs up by two. */
1888 memmove(rl
+ 2, rl
, (rl_real_end
- rl
+ 1) * sizeof(*rl
));
1889 /* Finally, setup the three split runs. */
1890 rl
->length
= start
- rl
->vcn
;
1894 rl
->length
= length
;
1896 delta
= end
- rl
->vcn
;
1899 rl
->length
-= delta
;
1900 ntfs_debug("Done (split both).");
1903 ntfs_error(vol
->sb
, "Not enough memory to extend runlist buffer.");
1907 #endif /* NTFS_RW */