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