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1da177e4 LT |
1 | /** |
2 | * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. | |
3 | * | |
1a0df15a | 4 | * Copyright (c) 2001-2005 Anton Altaparmakov |
5c9f6de3 | 5 | * Copyright (c) 2002-2005 Richard Russon |
1da177e4 LT |
6 | * |
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. | |
11 | * | |
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. | |
16 | * | |
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 | |
21 | */ | |
22 | ||
23 | #include "debug.h" | |
24 | #include "dir.h" | |
25 | #include "endian.h" | |
26 | #include "malloc.h" | |
27 | #include "ntfs.h" | |
28 | ||
29 | /** | |
30 | * ntfs_rl_mm - runlist memmove | |
31 | * | |
32 | * It is up to the caller to serialize access to the runlist @base. | |
33 | */ | |
34 | static inline void ntfs_rl_mm(runlist_element *base, int dst, int src, | |
35 | int size) | |
36 | { | |
37 | if (likely((dst != src) && (size > 0))) | |
9529d461 | 38 | memmove(base + dst, base + src, size * sizeof(*base)); |
1da177e4 LT |
39 | } |
40 | ||
41 | /** | |
42 | * ntfs_rl_mc - runlist memory copy | |
43 | * | |
44 | * It is up to the caller to serialize access to the runlists @dstbase and | |
45 | * @srcbase. | |
46 | */ | |
47 | static inline void ntfs_rl_mc(runlist_element *dstbase, int dst, | |
48 | runlist_element *srcbase, int src, int size) | |
49 | { | |
50 | if (likely(size > 0)) | |
51 | memcpy(dstbase + dst, srcbase + src, size * sizeof(*dstbase)); | |
52 | } | |
53 | ||
54 | /** | |
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 | |
59 | * | |
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 | |
1a0df15a | 62 | * memory, this function returns an entire page of memory. |
1da177e4 LT |
63 | * |
64 | * It is up to the caller to serialize access to the runlist @rl. | |
65 | * | |
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. | |
68 | * | |
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. | |
73 | */ | |
74 | static inline runlist_element *ntfs_rl_realloc(runlist_element *rl, | |
75 | int old_size, int new_size) | |
76 | { | |
77 | runlist_element *new_rl; | |
78 | ||
79 | old_size = PAGE_ALIGN(old_size * sizeof(*rl)); | |
80 | new_size = PAGE_ALIGN(new_size * sizeof(*rl)); | |
81 | if (old_size == new_size) | |
82 | return rl; | |
83 | ||
84 | new_rl = ntfs_malloc_nofs(new_size); | |
85 | if (unlikely(!new_rl)) | |
86 | return ERR_PTR(-ENOMEM); | |
87 | ||
88 | if (likely(rl != NULL)) { | |
89 | if (unlikely(old_size > new_size)) | |
90 | old_size = new_size; | |
91 | memcpy(new_rl, rl, old_size); | |
92 | ntfs_free(rl); | |
93 | } | |
94 | return new_rl; | |
95 | } | |
96 | ||
9529d461 AA |
97 | /** |
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 | |
102 | * | |
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. | |
106 | * | |
107 | * This function guarantees that the allocation will succeed. It will sleep | |
108 | * for as long as it takes to complete the allocation. | |
109 | * | |
110 | * It is up to the caller to serialize access to the runlist @rl. | |
111 | * | |
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. | |
114 | * | |
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. | |
119 | */ | |
120 | static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl, | |
121 | int old_size, int new_size) | |
122 | { | |
123 | runlist_element *new_rl; | |
124 | ||
125 | old_size = PAGE_ALIGN(old_size * sizeof(*rl)); | |
126 | new_size = PAGE_ALIGN(new_size * sizeof(*rl)); | |
127 | if (old_size == new_size) | |
128 | return rl; | |
129 | ||
130 | new_rl = ntfs_malloc_nofs_nofail(new_size); | |
131 | BUG_ON(!new_rl); | |
132 | ||
133 | if (likely(rl != NULL)) { | |
134 | if (unlikely(old_size > new_size)) | |
135 | old_size = new_size; | |
136 | memcpy(new_rl, rl, old_size); | |
137 | ntfs_free(rl); | |
138 | } | |
139 | return new_rl; | |
140 | } | |
141 | ||
1da177e4 LT |
142 | /** |
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 | |
146 | * | |
147 | * Test if two runlists can be joined together. For this, their VCNs and LCNs | |
148 | * must be adjacent. | |
149 | * | |
150 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
151 | * | |
152 | * Return: TRUE Success, the runlists can be merged. | |
153 | * FALSE Failure, the runlists cannot be merged. | |
154 | */ | |
155 | static inline BOOL ntfs_are_rl_mergeable(runlist_element *dst, | |
156 | runlist_element *src) | |
157 | { | |
158 | BUG_ON(!dst); | |
159 | BUG_ON(!src); | |
160 | ||
37e4c13b AA |
161 | if ((dst->lcn < 0) || (src->lcn < 0)) { /* Are we merging holes? */ |
162 | if (dst->lcn == LCN_HOLE && src->lcn == LCN_HOLE) | |
163 | return TRUE; | |
1da177e4 | 164 | return FALSE; |
37e4c13b | 165 | } |
1da177e4 LT |
166 | if ((dst->lcn + dst->length) != src->lcn) /* Are the runs contiguous? */ |
167 | return FALSE; | |
168 | if ((dst->vcn + dst->length) != src->vcn) /* Are the runs misaligned? */ | |
169 | return FALSE; | |
170 | ||
171 | return TRUE; | |
172 | } | |
173 | ||
174 | /** | |
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 | |
178 | * | |
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. | |
182 | * | |
183 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
184 | */ | |
185 | static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) | |
186 | { | |
187 | dst->length += src->length; | |
188 | } | |
189 | ||
190 | /** | |
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 | |
197 | * | |
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 | |
200 | * appended runlist. | |
201 | * | |
202 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
203 | * | |
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.) | |
208 | * | |
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. | |
213 | */ | |
214 | static inline runlist_element *ntfs_rl_append(runlist_element *dst, | |
215 | int dsize, runlist_element *src, int ssize, int loc) | |
216 | { | |
5c9f6de3 AA |
217 | BOOL right; /* Right end of @src needs merging. */ |
218 | int marker; /* End of the inserted runs. */ | |
1da177e4 LT |
219 | |
220 | BUG_ON(!dst); | |
221 | BUG_ON(!src); | |
222 | ||
223 | /* First, check if the right hand end needs merging. */ | |
224 | right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); | |
225 | ||
226 | /* Space required: @dst size + @src size, less one if we merged. */ | |
227 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right); | |
228 | if (IS_ERR(dst)) | |
229 | return dst; | |
230 | /* | |
231 | * We are guaranteed to succeed from here so can start modifying the | |
232 | * original runlists. | |
233 | */ | |
234 | ||
235 | /* First, merge the right hand end, if necessary. */ | |
236 | if (right) | |
237 | __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); | |
238 | ||
5c9f6de3 AA |
239 | /* First run after the @src runs that have been inserted. */ |
240 | marker = loc + ssize + 1; | |
1da177e4 LT |
241 | |
242 | /* Move the tail of @dst out of the way, then copy in @src. */ | |
5c9f6de3 | 243 | ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right)); |
1da177e4 LT |
244 | ntfs_rl_mc(dst, loc + 1, src, 0, ssize); |
245 | ||
246 | /* Adjust the size of the preceding hole. */ | |
247 | dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; | |
248 | ||
249 | /* We may have changed the length of the file, so fix the end marker */ | |
5c9f6de3 AA |
250 | if (dst[marker].lcn == LCN_ENOENT) |
251 | dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; | |
1da177e4 LT |
252 | |
253 | return dst; | |
254 | } | |
255 | ||
256 | /** | |
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 | |
263 | * | |
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. | |
267 | * | |
268 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
269 | * | |
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.) | |
274 | * | |
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. | |
279 | */ | |
280 | static inline runlist_element *ntfs_rl_insert(runlist_element *dst, | |
281 | int dsize, runlist_element *src, int ssize, int loc) | |
282 | { | |
5c9f6de3 AA |
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. */ | |
1da177e4 LT |
286 | |
287 | BUG_ON(!dst); | |
288 | BUG_ON(!src); | |
289 | ||
5c9f6de3 AA |
290 | /* |
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. | |
293 | */ | |
1da177e4 LT |
294 | if (loc == 0) |
295 | disc = (src[0].vcn > 0); | |
296 | else { | |
297 | s64 merged_length; | |
298 | ||
299 | left = ntfs_are_rl_mergeable(dst + loc - 1, src); | |
300 | ||
301 | merged_length = dst[loc - 1].length; | |
302 | if (left) | |
303 | merged_length += src->length; | |
304 | ||
305 | disc = (src[0].vcn > dst[loc - 1].vcn + merged_length); | |
1da177e4 | 306 | } |
5c9f6de3 AA |
307 | /* |
308 | * Space required: @dst size + @src size, less one if we merged, plus | |
309 | * one if there was a discontinuity. | |
310 | */ | |
311 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc); | |
1da177e4 LT |
312 | if (IS_ERR(dst)) |
313 | return dst; | |
314 | /* | |
315 | * We are guaranteed to succeed from here so can start modifying the | |
316 | * original runlist. | |
317 | */ | |
1da177e4 LT |
318 | if (left) |
319 | __ntfs_rl_merge(dst + loc - 1, src); | |
5c9f6de3 AA |
320 | /* |
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. | |
326 | */ | |
327 | marker = loc + ssize - left + disc; | |
1da177e4 LT |
328 | |
329 | /* Move the tail of @dst out of the way, then copy in @src. */ | |
5c9f6de3 AA |
330 | ntfs_rl_mm(dst, marker, loc, dsize - loc); |
331 | ntfs_rl_mc(dst, loc + disc, src, left, ssize - left); | |
1da177e4 | 332 | |
5c9f6de3 AA |
333 | /* Adjust the VCN of the first run after the insertion... */ |
334 | dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; | |
1da177e4 | 335 | /* ... and the length. */ |
5c9f6de3 AA |
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; | |
1da177e4 | 338 | |
5c9f6de3 | 339 | /* Writing beyond the end of the file and there is a discontinuity. */ |
1da177e4 | 340 | if (disc) { |
5c9f6de3 AA |
341 | if (loc > 0) { |
342 | dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length; | |
343 | dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; | |
344 | } else { | |
345 | dst[loc].vcn = 0; | |
346 | dst[loc].length = dst[loc + 1].vcn; | |
1da177e4 | 347 | } |
5c9f6de3 | 348 | dst[loc].lcn = LCN_RL_NOT_MAPPED; |
1da177e4 LT |
349 | } |
350 | return dst; | |
351 | } | |
352 | ||
353 | /** | |
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 | |
360 | * | |
361 | * Replace the runlist element @dst at @loc with @src. Merge the left and | |
362 | * right ends of the inserted runlist, if necessary. | |
363 | * | |
364 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
365 | * | |
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.) | |
370 | * | |
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. | |
375 | */ | |
376 | static inline runlist_element *ntfs_rl_replace(runlist_element *dst, | |
377 | int dsize, runlist_element *src, int ssize, int loc) | |
378 | { | |
5c9f6de3 AA |
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. */ | |
1da177e4 LT |
383 | |
384 | BUG_ON(!dst); | |
385 | BUG_ON(!src); | |
386 | ||
387 | /* First, merge the left and right ends, if necessary. */ | |
388 | right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); | |
389 | if (loc > 0) | |
390 | left = ntfs_are_rl_mergeable(dst + loc - 1, src); | |
5c9f6de3 AA |
391 | /* |
392 | * Allocate some space. We will need less if the left, right, or both | |
393 | * ends were merged. | |
394 | */ | |
1da177e4 LT |
395 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right); |
396 | if (IS_ERR(dst)) | |
397 | return dst; | |
398 | /* | |
399 | * We are guaranteed to succeed from here so can start modifying the | |
400 | * original runlists. | |
401 | */ | |
402 | if (right) | |
403 | __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); | |
404 | if (left) | |
405 | __ntfs_rl_merge(dst + loc - 1, src); | |
5c9f6de3 AA |
406 | /* |
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 | |
409 | * tail of @dst. | |
410 | */ | |
411 | tail = loc + right + 1; | |
412 | /* | |
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. | |
418 | */ | |
419 | marker = loc + ssize - left; | |
1da177e4 LT |
420 | |
421 | /* Move the tail of @dst out of the way, then copy in @src. */ | |
5c9f6de3 | 422 | ntfs_rl_mm(dst, marker, tail, dsize - tail); |
1da177e4 LT |
423 | ntfs_rl_mc(dst, loc, src, left, ssize - left); |
424 | ||
5c9f6de3 AA |
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; | |
1da177e4 LT |
428 | return dst; |
429 | } | |
430 | ||
431 | /** | |
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 | |
438 | * | |
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 | |
441 | * holes either side. | |
442 | * | |
443 | * It is up to the caller to serialize access to the runlists @dst and @src. | |
444 | * | |
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.) | |
449 | * | |
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. | |
454 | */ | |
455 | static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize, | |
456 | runlist_element *src, int ssize, int loc) | |
457 | { | |
458 | BUG_ON(!dst); | |
459 | BUG_ON(!src); | |
460 | ||
461 | /* Space required: @dst size + @src size + one new hole. */ | |
462 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1); | |
463 | if (IS_ERR(dst)) | |
464 | return dst; | |
465 | /* | |
466 | * We are guaranteed to succeed from here so can start modifying the | |
467 | * original runlists. | |
468 | */ | |
469 | ||
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); | |
473 | ||
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; | |
478 | ||
479 | return dst; | |
480 | } | |
481 | ||
482 | /** | |
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 | |
486 | * | |
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. | |
490 | * | |
491 | * It is up to the caller to serialize access to the runlists @drl and @srl. | |
492 | * | |
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. | |
496 | * | |
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. | |
504 | * | |
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.) | |
509 | * | |
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. | |
515 | */ | |
516 | runlist_element *ntfs_runlists_merge(runlist_element *drl, | |
517 | runlist_element *srl) | |
518 | { | |
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 | |
524 | lcn >= LCN_HOLE. */ | |
525 | int marker = 0; | |
526 | VCN marker_vcn = 0; | |
527 | ||
528 | #ifdef DEBUG | |
529 | ntfs_debug("dst:"); | |
530 | ntfs_debug_dump_runlist(drl); | |
531 | ntfs_debug("src:"); | |
532 | ntfs_debug_dump_runlist(srl); | |
533 | #endif | |
534 | ||
535 | /* Check for silly calling... */ | |
536 | if (unlikely(!srl)) | |
537 | return drl; | |
538 | if (IS_ERR(srl) || IS_ERR(drl)) | |
539 | return ERR_PTR(-EINVAL); | |
540 | ||
541 | /* Check for the case where the first mapping is being done now. */ | |
542 | if (unlikely(!drl)) { | |
543 | drl = srl; | |
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++) | |
548 | ; | |
84d6ebe6 | 549 | dend++; |
1da177e4 LT |
550 | drl = ntfs_rl_realloc(drl, dend, dend + 1); |
551 | if (IS_ERR(drl)) | |
552 | return drl; | |
553 | /* Insert start element at the front of the runlist. */ | |
554 | ntfs_rl_mm(drl, 1, 0, dend); | |
555 | drl[0].vcn = 0; | |
556 | drl[0].lcn = LCN_RL_NOT_MAPPED; | |
557 | drl[0].length = drl[1].vcn; | |
558 | } | |
559 | goto finished; | |
560 | } | |
561 | ||
562 | si = di = 0; | |
563 | ||
564 | /* Skip any unmapped start element(s) in the source runlist. */ | |
565 | while (srl[si].length && srl[si].lcn < LCN_HOLE) | |
566 | si++; | |
567 | ||
568 | /* Can't have an entirely unmapped source runlist. */ | |
569 | BUG_ON(!srl[si].length); | |
570 | ||
571 | /* Record the starting points. */ | |
572 | sstart = si; | |
573 | ||
574 | /* | |
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 | |
577 | * appended to @drl. | |
578 | */ | |
579 | for (; drl[di].length; di++) { | |
580 | if (drl[di].vcn + drl[di].length > srl[sstart].vcn) | |
581 | break; | |
582 | } | |
583 | dins = di; | |
584 | ||
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); | |
590 | } | |
591 | ||
592 | /* Scan to the end of both runlists in order to know their sizes. */ | |
593 | for (send = si; srl[send].length; send++) | |
594 | ; | |
595 | for (dend = di; drl[dend].length; dend++) | |
596 | ; | |
597 | ||
598 | if (srl[send].lcn == LCN_ENOENT) | |
599 | marker_vcn = srl[marker = send].vcn; | |
600 | ||
601 | /* Scan to the last element with lcn >= LCN_HOLE. */ | |
602 | for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--) | |
603 | ; | |
604 | for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--) | |
605 | ; | |
606 | ||
607 | { | |
608 | BOOL start; | |
609 | BOOL finish; | |
610 | int ds = dend + 1; /* Number of elements in drl & srl */ | |
611 | int ss = sfinal - sstart + 1; | |
612 | ||
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))); | |
618 | ||
84d6ebe6 AA |
619 | /* Or we will lose an end marker. */ |
620 | if (finish && !drl[dins].length) | |
1da177e4 LT |
621 | ss++; |
622 | if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn)) | |
623 | finish = FALSE; | |
624 | #if 0 | |
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); | |
629 | #endif | |
630 | if (start) { | |
631 | if (finish) | |
632 | drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins); | |
633 | else | |
634 | drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins); | |
635 | } else { | |
636 | if (finish) | |
637 | drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins); | |
638 | else | |
639 | drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins); | |
640 | } | |
641 | if (IS_ERR(drl)) { | |
642 | ntfs_error(NULL, "Merge failed."); | |
643 | return drl; | |
644 | } | |
645 | ntfs_free(srl); | |
646 | if (marker) { | |
647 | ntfs_debug("Triggering marker code."); | |
648 | for (ds = dend; drl[ds].length; ds++) | |
649 | ; | |
650 | /* We only need to care if @srl ended after @drl. */ | |
651 | if (drl[ds].vcn <= marker_vcn) { | |
652 | int slots = 0; | |
653 | ||
654 | if (drl[ds].vcn == marker_vcn) { | |
655 | ntfs_debug("Old marker = 0x%llx, replacing " | |
656 | "with LCN_ENOENT.", | |
657 | (unsigned long long) | |
658 | drl[ds].lcn); | |
659 | drl[ds].lcn = LCN_ENOENT; | |
660 | goto finished; | |
661 | } | |
662 | /* | |
663 | * We need to create an unmapped runlist element in | |
664 | * @drl or extend an existing one before adding the | |
665 | * ENOENT terminator. | |
666 | */ | |
667 | if (drl[ds].lcn == LCN_ENOENT) { | |
668 | ds--; | |
669 | slots = 1; | |
670 | } | |
671 | if (drl[ds].lcn != LCN_RL_NOT_MAPPED) { | |
672 | /* Add an unmapped runlist element. */ | |
673 | if (!slots) { | |
9529d461 AA |
674 | drl = ntfs_rl_realloc_nofail(drl, ds, |
675 | ds + 2); | |
1da177e4 LT |
676 | slots = 2; |
677 | } | |
678 | ds++; | |
679 | /* Need to set vcn if it isn't set already. */ | |
680 | if (slots != 1) | |
681 | drl[ds].vcn = drl[ds - 1].vcn + | |
682 | drl[ds - 1].length; | |
683 | drl[ds].lcn = LCN_RL_NOT_MAPPED; | |
684 | /* We now used up a slot. */ | |
685 | slots--; | |
686 | } | |
687 | drl[ds].length = marker_vcn - drl[ds].vcn; | |
688 | /* Finally add the ENOENT terminator. */ | |
689 | ds++; | |
9529d461 AA |
690 | if (!slots) |
691 | drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1); | |
1da177e4 LT |
692 | drl[ds].vcn = marker_vcn; |
693 | drl[ds].lcn = LCN_ENOENT; | |
694 | drl[ds].length = (s64)0; | |
695 | } | |
696 | } | |
697 | } | |
698 | ||
699 | finished: | |
700 | /* The merge was completed successfully. */ | |
701 | ntfs_debug("Merged runlist:"); | |
702 | ntfs_debug_dump_runlist(drl); | |
703 | return drl; | |
1da177e4 LT |
704 | } |
705 | ||
706 | /** | |
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 | |
711 | * | |
712 | * It is up to the caller to serialize access to the runlist @old_rl. | |
713 | * | |
714 | * Decompress the attribute @attr's mapping pairs array into a runlist. On | |
715 | * success, return the decompressed runlist. | |
716 | * | |
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. | |
720 | * | |
721 | * On error, return -errno. @old_rl is left unmodified in that case. | |
722 | * | |
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. | |
728 | * | |
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)). | |
733 | */ | |
734 | runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol, | |
735 | const ATTR_RECORD *attr, runlist_element *old_rl) | |
736 | { | |
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 | |
745 | runlist_elements. */ | |
746 | u8 b; /* Current byte offset in buf. */ | |
747 | ||
748 | #ifdef DEBUG | |
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); | |
754 | } | |
755 | #endif | |
756 | /* Start at vcn = lowest_vcn and lcn 0. */ | |
757 | vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn); | |
758 | lcn = 0; | |
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); | |
766 | } | |
2b0ada2b AA |
767 | /* If the mapping pairs array is valid but empty, nothing to do. */ |
768 | if (!vcn && !*buf) | |
769 | return old_rl; | |
1da177e4 LT |
770 | /* Current position in runlist array. */ |
771 | rlpos = 0; | |
772 | /* Allocate first page and set current runlist size to one page. */ | |
773 | rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE); | |
774 | if (unlikely(!rl)) | |
775 | return ERR_PTR(-ENOMEM); | |
776 | /* Insert unmapped starting element if necessary. */ | |
777 | if (vcn) { | |
778 | rl->vcn = 0; | |
779 | rl->lcn = LCN_RL_NOT_MAPPED; | |
780 | rl->length = vcn; | |
781 | rlpos++; | |
782 | } | |
783 | while (buf < attr_end && *buf) { | |
784 | /* | |
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. | |
788 | */ | |
789 | if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) { | |
790 | runlist_element *rl2; | |
791 | ||
792 | rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE); | |
793 | if (unlikely(!rl2)) { | |
794 | ntfs_free(rl); | |
795 | return ERR_PTR(-ENOMEM); | |
796 | } | |
797 | memcpy(rl2, rl, rlsize); | |
798 | ntfs_free(rl); | |
799 | rl = rl2; | |
800 | rlsize += PAGE_SIZE; | |
801 | } | |
802 | /* Enter the current vcn into the current runlist element. */ | |
803 | rl[rlpos].vcn = vcn; | |
804 | /* | |
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... | |
810 | */ | |
811 | b = *buf & 0xf; | |
812 | if (b) { | |
813 | if (unlikely(buf + b > attr_end)) | |
814 | goto io_error; | |
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 " | |
819 | "pairs array."); | |
820 | deltaxcn = (s64)-1; | |
821 | } | |
822 | /* | |
823 | * Assume a negative length to indicate data corruption and | |
824 | * hence clean-up and return NULL. | |
825 | */ | |
826 | if (unlikely(deltaxcn < 0)) { | |
827 | ntfs_error(vol->sb, "Invalid length in mapping pairs " | |
828 | "array."); | |
829 | goto err_out; | |
830 | } | |
831 | /* | |
832 | * Enter the current run length into the current runlist | |
833 | * element. | |
834 | */ | |
835 | rl[rlpos].length = deltaxcn; | |
836 | /* Increment the current vcn by the current run length. */ | |
837 | vcn += deltaxcn; | |
838 | /* | |
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 | |
841 | * to LCN_HOLE. | |
842 | */ | |
843 | if (!(*buf & 0xf0)) | |
844 | rl[rlpos].lcn = LCN_HOLE; | |
845 | else { | |
846 | /* Get the lcn change which really can be negative. */ | |
847 | u8 b2 = *buf & 0xf; | |
848 | b = b2 + ((*buf >> 4) & 0xf); | |
849 | if (buf + b > attr_end) | |
850 | goto io_error; | |
851 | for (deltaxcn = (s8)buf[b--]; b > b2; b--) | |
852 | deltaxcn = (deltaxcn << 8) + buf[b]; | |
853 | /* Change the current lcn to its new value. */ | |
854 | lcn += deltaxcn; | |
855 | #ifdef DEBUG | |
856 | /* | |
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! | |
862 | */ | |
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"); | |
868 | } | |
869 | #endif | |
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."); | |
874 | goto err_out; | |
875 | } | |
876 | /* Enter the current lcn into the runlist element. */ | |
877 | rl[rlpos].lcn = lcn; | |
878 | } | |
879 | /* Get to the next runlist element. */ | |
880 | rlpos++; | |
881 | /* Increment the buffer position to the next mapping pair. */ | |
882 | buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1; | |
883 | } | |
884 | if (unlikely(buf >= attr_end)) | |
885 | goto io_error; | |
886 | /* | |
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. | |
889 | */ | |
890 | deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn); | |
891 | if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) { | |
892 | mpa_err: | |
893 | ntfs_error(vol->sb, "Corrupt mapping pairs array in " | |
894 | "non-resident attribute."); | |
895 | goto err_out; | |
896 | } | |
897 | /* Setup not mapped runlist element if this is the base extent. */ | |
898 | if (!attr->data.non_resident.lowest_vcn) { | |
899 | VCN max_cluster; | |
900 | ||
1a0df15a | 901 | max_cluster = ((sle64_to_cpu( |
1da177e4 LT |
902 | attr->data.non_resident.allocated_size) + |
903 | vol->cluster_size - 1) >> | |
1a0df15a | 904 | vol->cluster_size_bits) - 1; |
1da177e4 | 905 | /* |
1a0df15a AA |
906 | * A highest_vcn of zero means this is a single extent |
907 | * attribute so simply terminate the runlist with LCN_ENOENT). | |
1da177e4 | 908 | */ |
1a0df15a AA |
909 | if (deltaxcn) { |
910 | /* | |
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 | |
914 | * this one. | |
915 | */ | |
916 | if (deltaxcn < max_cluster) { | |
917 | ntfs_debug("More extents to follow; deltaxcn " | |
918 | "= 0x%llx, max_cluster = " | |
919 | "0x%llx", | |
920 | (unsigned long long)deltaxcn, | |
921 | (unsigned long long) | |
922 | max_cluster); | |
923 | rl[rlpos].vcn = vcn; | |
924 | vcn += rl[rlpos].length = max_cluster - | |
925 | deltaxcn; | |
926 | rl[rlpos].lcn = LCN_RL_NOT_MAPPED; | |
927 | rlpos++; | |
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, | |
933 | (unsigned long long) | |
934 | max_cluster); | |
935 | goto mpa_err; | |
936 | } | |
1da177e4 LT |
937 | } |
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; | |
941 | ||
942 | /* Setup terminating runlist element. */ | |
943 | rl[rlpos].vcn = vcn; | |
944 | rl[rlpos].length = (s64)0; | |
945 | /* If no existing runlist was specified, we are done. */ | |
946 | if (!old_rl) { | |
947 | ntfs_debug("Mapping pairs array successfully decompressed:"); | |
948 | ntfs_debug_dump_runlist(rl); | |
949 | return rl; | |
950 | } | |
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))) | |
954 | return old_rl; | |
955 | ntfs_free(rl); | |
956 | ntfs_error(vol->sb, "Failed to merge runlists."); | |
957 | return old_rl; | |
958 | io_error: | |
959 | ntfs_error(vol->sb, "Corrupt attribute."); | |
960 | err_out: | |
961 | ntfs_free(rl); | |
962 | return ERR_PTR(-EIO); | |
963 | } | |
964 | ||
965 | /** | |
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 | |
969 | * | |
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. | |
973 | * | |
974 | * It is up to the caller to serialize access to the runlist @rl. | |
975 | * | |
c0c1cc0e | 976 | * Since lcns must be >= 0, we use negative return codes with special meaning: |
1da177e4 | 977 | * |
c0c1cc0e | 978 | * Return code Meaning / Description |
1da177e4 | 979 | * ================================================== |
c0c1cc0e AA |
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. | |
1da177e4 LT |
984 | * |
985 | * Locking: - The caller must have locked the runlist (for reading or writing). | |
c0c1cc0e AA |
986 | * - This function does not touch the lock, nor does it modify the |
987 | * runlist. | |
1da177e4 LT |
988 | */ |
989 | LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn) | |
990 | { | |
991 | int i; | |
992 | ||
993 | BUG_ON(vcn < 0); | |
994 | /* | |
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 | |
997 | * necessary. | |
998 | */ | |
999 | if (unlikely(!rl)) | |
1000 | return LCN_RL_NOT_MAPPED; | |
1001 | ||
1002 | /* Catch out of lower bounds vcn. */ | |
1003 | if (unlikely(vcn < rl[0].vcn)) | |
1004 | return LCN_ENOENT; | |
1005 | ||
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); | |
1010 | return rl[i].lcn; | |
1011 | } | |
1012 | } | |
1013 | /* | |
1014 | * The terminator element is setup to the correct value, i.e. one of | |
1015 | * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT. | |
1016 | */ | |
1017 | if (likely(rl[i].lcn < (LCN)0)) | |
1018 | return rl[i].lcn; | |
1019 | /* Just in case... We could replace this with BUG() some day. */ | |
1020 | return LCN_ENOENT; | |
1021 | } | |
1022 | ||
53d59aad AA |
1023 | #ifdef NTFS_RW |
1024 | ||
1025 | /** | |
1026 | * ntfs_rl_find_vcn_nolock - find a vcn in a runlist | |
1027 | * @rl: runlist to search | |
1028 | * @vcn: vcn to find | |
1029 | * | |
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. | |
1032 | * | |
1033 | * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of | |
1034 | * the runlist. | |
1035 | * | |
1036 | * Locking: The runlist must be locked on entry. | |
1037 | */ | |
1038 | runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl, const VCN vcn) | |
1039 | { | |
1040 | BUG_ON(vcn < 0); | |
1041 | if (unlikely(!rl || vcn < rl[0].vcn)) | |
1042 | return NULL; | |
1043 | while (likely(rl->length)) { | |
1044 | if (unlikely(vcn < rl[1].vcn)) { | |
1045 | if (likely(rl->lcn >= LCN_HOLE)) | |
1046 | return rl; | |
1047 | return NULL; | |
1048 | } | |
1049 | rl++; | |
1050 | } | |
1051 | if (likely(rl->lcn == LCN_ENOENT)) | |
1052 | return rl; | |
1053 | return NULL; | |
1054 | } | |
1055 | ||
1da177e4 LT |
1056 | /** |
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 | |
1059 | * | |
1060 | * Return the number of bytes required to store @n unambiguously as | |
1061 | * a signed number. | |
1062 | * | |
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. | |
1066 | * | |
1067 | * Return the number of bytes written. This function cannot fail. | |
1068 | */ | |
1069 | static inline int ntfs_get_nr_significant_bytes(const s64 n) | |
1070 | { | |
1071 | s64 l = n; | |
1072 | int i; | |
1073 | s8 j; | |
1074 | ||
1075 | i = 0; | |
1076 | do { | |
1077 | l >>= 8; | |
1078 | i++; | |
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)) | |
1083 | i++; | |
1084 | return i; | |
1085 | } | |
1086 | ||
1087 | /** | |
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 | |
fa3be923 AA |
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 | |
1da177e4 LT |
1093 | * |
1094 | * Walk the locked runlist @rl and calculate the size in bytes of the mapping | |
fa3be923 AA |
1095 | * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and |
1096 | * finishing with vcn @last_vcn. | |
1097 | * | |
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. | |
1101 | * | |
1da177e4 LT |
1102 | * This for example allows us to allocate a buffer of the right size when |
1103 | * building the mapping pairs array. | |
1104 | * | |
1105 | * If @rl is NULL, just return 1 (for the single terminator byte). | |
1106 | * | |
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. | |
1112 | * | |
1113 | * Locking: @rl must be locked on entry (either for reading or writing), it | |
1114 | * remains locked throughout, and is left locked upon return. | |
1115 | */ | |
1116 | int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, | |
fa3be923 AA |
1117 | const runlist_element *rl, const VCN first_vcn, |
1118 | const VCN last_vcn) | |
1da177e4 LT |
1119 | { |
1120 | LCN prev_lcn; | |
1121 | int rls; | |
fa3be923 | 1122 | BOOL the_end = FALSE; |
1da177e4 | 1123 | |
fa3be923 AA |
1124 | BUG_ON(first_vcn < 0); |
1125 | BUG_ON(last_vcn < -1); | |
1126 | BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); | |
1da177e4 | 1127 | if (!rl) { |
fa3be923 AA |
1128 | BUG_ON(first_vcn); |
1129 | BUG_ON(last_vcn > 0); | |
1da177e4 LT |
1130 | return 1; |
1131 | } | |
fa3be923 AA |
1132 | /* Skip to runlist element containing @first_vcn. */ |
1133 | while (rl->length && first_vcn >= rl[1].vcn) | |
1da177e4 | 1134 | rl++; |
fa3be923 AA |
1135 | if (unlikely((!rl->length && first_vcn > rl->vcn) || |
1136 | first_vcn < rl->vcn)) | |
1da177e4 LT |
1137 | return -EINVAL; |
1138 | prev_lcn = 0; | |
1139 | /* Always need the termining zero byte. */ | |
1140 | rls = 1; | |
1141 | /* Do the first partial run if present. */ | |
fa3be923 AA |
1142 | if (first_vcn > rl->vcn) { |
1143 | s64 delta, length = rl->length; | |
1da177e4 LT |
1144 | |
1145 | /* We know rl->length != 0 already. */ | |
fa3be923 | 1146 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
1da177e4 | 1147 | goto err_out; |
fa3be923 AA |
1148 | /* |
1149 | * If @stop_vcn is given and finishes inside this run, cap the | |
1150 | * run length. | |
1151 | */ | |
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; | |
1156 | the_end = TRUE; | |
1157 | } | |
1158 | delta = first_vcn - rl->vcn; | |
1da177e4 | 1159 | /* Header byte + length. */ |
fa3be923 | 1160 | rls += 1 + ntfs_get_nr_significant_bytes(length - delta); |
1da177e4 LT |
1161 | /* |
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). | |
1167 | */ | |
fa3be923 | 1168 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
1da177e4 | 1169 | prev_lcn = rl->lcn; |
fa3be923 | 1170 | if (likely(rl->lcn >= 0)) |
1da177e4 LT |
1171 | prev_lcn += delta; |
1172 | /* Change in lcn. */ | |
1173 | rls += ntfs_get_nr_significant_bytes(prev_lcn); | |
1174 | } | |
1175 | /* Go to next runlist element. */ | |
1176 | rl++; | |
1177 | } | |
1178 | /* Do the full runs. */ | |
fa3be923 AA |
1179 | for (; rl->length && !the_end; rl++) { |
1180 | s64 length = rl->length; | |
1181 | ||
1182 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) | |
1da177e4 | 1183 | goto err_out; |
fa3be923 AA |
1184 | /* |
1185 | * If @stop_vcn is given and finishes inside this run, cap the | |
1186 | * run length. | |
1187 | */ | |
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; | |
1192 | the_end = TRUE; | |
1193 | } | |
1da177e4 | 1194 | /* Header byte + length. */ |
fa3be923 | 1195 | rls += 1 + ntfs_get_nr_significant_bytes(length); |
1da177e4 LT |
1196 | /* |
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). | |
1202 | */ | |
fa3be923 | 1203 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
1da177e4 LT |
1204 | /* Change in lcn. */ |
1205 | rls += ntfs_get_nr_significant_bytes(rl->lcn - | |
1206 | prev_lcn); | |
1207 | prev_lcn = rl->lcn; | |
1208 | } | |
1209 | } | |
1210 | return rls; | |
1211 | err_out: | |
1212 | if (rl->lcn == LCN_RL_NOT_MAPPED) | |
1213 | rls = -EINVAL; | |
1214 | else | |
1215 | rls = -EIO; | |
1216 | return rls; | |
1217 | } | |
1218 | ||
1219 | /** | |
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 | |
1224 | * | |
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 | |
1228 | * write. | |
1229 | * | |
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 | |
1232 | * size possible. | |
1233 | * | |
1234 | * Return the number of bytes written on success. On error, i.e. the | |
1235 | * destination buffer @dst is too small, return -ENOSPC. | |
1236 | */ | |
1237 | static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, | |
1238 | const s64 n) | |
1239 | { | |
1240 | s64 l = n; | |
1241 | int i; | |
1242 | s8 j; | |
1243 | ||
1244 | i = 0; | |
1245 | do { | |
fa3be923 | 1246 | if (unlikely(dst > dst_max)) |
1da177e4 LT |
1247 | goto err_out; |
1248 | *dst++ = l & 0xffll; | |
1249 | l >>= 8; | |
1250 | i++; | |
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) { | |
fa3be923 | 1255 | if (unlikely(dst > dst_max)) |
1da177e4 LT |
1256 | goto err_out; |
1257 | i++; | |
1258 | *dst = (s8)-1; | |
1259 | } else if (n > 0 && j < 0) { | |
fa3be923 | 1260 | if (unlikely(dst > dst_max)) |
1da177e4 LT |
1261 | goto err_out; |
1262 | i++; | |
1263 | *dst = (s8)0; | |
1264 | } | |
1265 | return i; | |
1266 | err_out: | |
1267 | return -ENOSPC; | |
1268 | } | |
1269 | ||
1270 | /** | |
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 | |
fa3be923 AA |
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 | |
1da177e4 LT |
1278 | * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC |
1279 | * | |
1280 | * Create the mapping pairs array from the locked runlist @rl, starting at vcn | |
fa3be923 AA |
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(). | |
1284 | * | |
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. | |
1da177e4 LT |
1288 | * |
1289 | * If @rl is NULL, just write a single terminator byte to @dst. | |
1290 | * | |
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 | |
fa3be923 | 1296 | * continued with @first_vcn set to *@stop_vcn. |
1da177e4 LT |
1297 | * |
1298 | * Return 0 on success and -errno on error. The following error codes are | |
1299 | * defined: | |
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. | |
1304 | * | |
1305 | * Locking: @rl must be locked on entry (either for reading or writing), it | |
1306 | * remains locked throughout, and is left locked upon return. | |
1307 | */ | |
1308 | int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, | |
1309 | const int dst_len, const runlist_element *rl, | |
fa3be923 | 1310 | const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn) |
1da177e4 LT |
1311 | { |
1312 | LCN prev_lcn; | |
1313 | s8 *dst_max, *dst_next; | |
1314 | int err = -ENOSPC; | |
fa3be923 | 1315 | BOOL the_end = FALSE; |
1da177e4 LT |
1316 | s8 len_len, lcn_len; |
1317 | ||
fa3be923 AA |
1318 | BUG_ON(first_vcn < 0); |
1319 | BUG_ON(last_vcn < -1); | |
1320 | BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); | |
1da177e4 LT |
1321 | BUG_ON(dst_len < 1); |
1322 | if (!rl) { | |
fa3be923 AA |
1323 | BUG_ON(first_vcn); |
1324 | BUG_ON(last_vcn > 0); | |
1da177e4 LT |
1325 | if (stop_vcn) |
1326 | *stop_vcn = 0; | |
1327 | /* Terminator byte. */ | |
1328 | *dst = 0; | |
1329 | return 0; | |
1330 | } | |
fa3be923 AA |
1331 | /* Skip to runlist element containing @first_vcn. */ |
1332 | while (rl->length && first_vcn >= rl[1].vcn) | |
1da177e4 | 1333 | rl++; |
fa3be923 AA |
1334 | if (unlikely((!rl->length && first_vcn > rl->vcn) || |
1335 | first_vcn < rl->vcn)) | |
1da177e4 LT |
1336 | return -EINVAL; |
1337 | /* | |
1338 | * @dst_max is used for bounds checking in | |
1339 | * ntfs_write_significant_bytes(). | |
1340 | */ | |
1341 | dst_max = dst + dst_len - 1; | |
1342 | prev_lcn = 0; | |
1343 | /* Do the first partial run if present. */ | |
fa3be923 AA |
1344 | if (first_vcn > rl->vcn) { |
1345 | s64 delta, length = rl->length; | |
1da177e4 LT |
1346 | |
1347 | /* We know rl->length != 0 already. */ | |
fa3be923 | 1348 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
1da177e4 | 1349 | goto err_out; |
fa3be923 AA |
1350 | /* |
1351 | * If @stop_vcn is given and finishes inside this run, cap the | |
1352 | * run length. | |
1353 | */ | |
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; | |
1358 | the_end = TRUE; | |
1359 | } | |
1360 | delta = first_vcn - rl->vcn; | |
1da177e4 LT |
1361 | /* Write length. */ |
1362 | len_len = ntfs_write_significant_bytes(dst + 1, dst_max, | |
fa3be923 AA |
1363 | length - delta); |
1364 | if (unlikely(len_len < 0)) | |
1da177e4 LT |
1365 | goto size_err; |
1366 | /* | |
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) | |
1374 | */ | |
fa3be923 | 1375 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
1da177e4 | 1376 | prev_lcn = rl->lcn; |
fa3be923 | 1377 | if (likely(rl->lcn >= 0)) |
1da177e4 LT |
1378 | prev_lcn += delta; |
1379 | /* Write change in lcn. */ | |
1380 | lcn_len = ntfs_write_significant_bytes(dst + 1 + | |
1381 | len_len, dst_max, prev_lcn); | |
fa3be923 | 1382 | if (unlikely(lcn_len < 0)) |
1da177e4 LT |
1383 | goto size_err; |
1384 | } else | |
1385 | lcn_len = 0; | |
1386 | dst_next = dst + len_len + lcn_len + 1; | |
fa3be923 | 1387 | if (unlikely(dst_next > dst_max)) |
1da177e4 LT |
1388 | goto size_err; |
1389 | /* Update header byte. */ | |
1390 | *dst = lcn_len << 4 | len_len; | |
1391 | /* Position at next mapping pairs array element. */ | |
1392 | dst = dst_next; | |
1393 | /* Go to next runlist element. */ | |
1394 | rl++; | |
1395 | } | |
1396 | /* Do the full runs. */ | |
fa3be923 AA |
1397 | for (; rl->length && !the_end; rl++) { |
1398 | s64 length = rl->length; | |
1399 | ||
1400 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) | |
1da177e4 | 1401 | goto err_out; |
fa3be923 AA |
1402 | /* |
1403 | * If @stop_vcn is given and finishes inside this run, cap the | |
1404 | * run length. | |
1405 | */ | |
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; | |
1410 | the_end = TRUE; | |
1411 | } | |
1da177e4 LT |
1412 | /* Write length. */ |
1413 | len_len = ntfs_write_significant_bytes(dst + 1, dst_max, | |
fa3be923 AA |
1414 | length); |
1415 | if (unlikely(len_len < 0)) | |
1da177e4 LT |
1416 | goto size_err; |
1417 | /* | |
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) | |
1425 | */ | |
fa3be923 | 1426 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
1da177e4 LT |
1427 | /* Write change in lcn. */ |
1428 | lcn_len = ntfs_write_significant_bytes(dst + 1 + | |
1429 | len_len, dst_max, rl->lcn - prev_lcn); | |
fa3be923 | 1430 | if (unlikely(lcn_len < 0)) |
1da177e4 LT |
1431 | goto size_err; |
1432 | prev_lcn = rl->lcn; | |
1433 | } else | |
1434 | lcn_len = 0; | |
1435 | dst_next = dst + len_len + lcn_len + 1; | |
fa3be923 | 1436 | if (unlikely(dst_next > dst_max)) |
1da177e4 LT |
1437 | goto size_err; |
1438 | /* Update header byte. */ | |
1439 | *dst = lcn_len << 4 | len_len; | |
1440 | /* Position at next mapping pairs array element. */ | |
1441 | dst = dst_next; | |
1442 | } | |
1443 | /* Success. */ | |
1444 | err = 0; | |
1445 | size_err: | |
1446 | /* Set stop vcn. */ | |
1447 | if (stop_vcn) | |
1448 | *stop_vcn = rl->vcn; | |
1449 | /* Add terminator byte. */ | |
1450 | *dst = 0; | |
1451 | return err; | |
1452 | err_out: | |
1453 | if (rl->lcn == LCN_RL_NOT_MAPPED) | |
1454 | err = -EINVAL; | |
1455 | else | |
1456 | err = -EIO; | |
1457 | return err; | |
1458 | } | |
1459 | ||
1460 | /** | |
1461 | * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn | |
3ffc5a44 | 1462 | * @vol: ntfs volume (needed for error output) |
1da177e4 LT |
1463 | * @runlist: runlist to truncate |
1464 | * @new_length: the new length of the runlist in VCNs | |
1465 | * | |
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. | |
1468 | * | |
1469 | * If @new_length lies within the runlist, the runlist elements with VCNs of | |
3ffc5a44 AA |
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. | |
1da177e4 LT |
1472 | * |
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. | |
1476 | * | |
3ffc5a44 AA |
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. | |
1479 | * | |
1da177e4 LT |
1480 | * Return 0 on success and -errno on error. |
1481 | * | |
1482 | * Locking: The caller must hold @runlist->lock for writing. | |
1483 | */ | |
1484 | int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, | |
1485 | const s64 new_length) | |
1486 | { | |
1487 | runlist_element *rl; | |
1488 | int old_size; | |
1489 | ||
1490 | ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length); | |
1491 | BUG_ON(!runlist); | |
1492 | BUG_ON(new_length < 0); | |
1493 | rl = runlist->rl; | |
3ffc5a44 AA |
1494 | if (!new_length) { |
1495 | ntfs_debug("Freeing runlist."); | |
1496 | runlist->rl = NULL; | |
1497 | if (rl) | |
1498 | ntfs_free(rl); | |
1499 | return 0; | |
1500 | } | |
1da177e4 LT |
1501 | if (unlikely(!rl)) { |
1502 | /* | |
1503 | * Create a runlist consisting of a sparse runlist element of | |
1504 | * length @new_length followed by a terminator runlist element. | |
1505 | */ | |
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."); | |
1510 | return -ENOMEM; | |
1511 | } | |
1512 | runlist->rl = rl; | |
1513 | rl[1].length = rl->vcn = 0; | |
1514 | rl->lcn = LCN_HOLE; | |
1515 | rl[1].vcn = rl->length = new_length; | |
1516 | rl[1].lcn = LCN_ENOENT; | |
1517 | return 0; | |
1518 | } | |
1519 | BUG_ON(new_length < rl->vcn); | |
1520 | /* Find @new_length in the runlist. */ | |
1521 | while (likely(rl->length && new_length >= rl[1].vcn)) | |
1522 | rl++; | |
1523 | /* | |
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. | |
1526 | */ | |
1527 | if (rl->length) { | |
1528 | runlist_element *trl; | |
1529 | BOOL is_end; | |
1530 | ||
1531 | ntfs_debug("Shrinking runlist."); | |
1532 | /* Determine the runlist size. */ | |
1533 | trl = rl + 1; | |
1534 | while (likely(trl->length)) | |
1535 | trl++; | |
1536 | old_size = trl - runlist->rl + 1; | |
1537 | /* Truncate the run. */ | |
1538 | rl->length = new_length - rl->vcn; | |
1539 | /* | |
1540 | * If a run was partially truncated, make the following runlist | |
1541 | * element a terminator. | |
1542 | */ | |
1543 | is_end = FALSE; | |
1544 | if (rl->length) { | |
1545 | rl++; | |
1546 | if (!rl->length) | |
1547 | is_end = TRUE; | |
1548 | rl->vcn = new_length; | |
1549 | rl->length = 0; | |
1550 | } | |
1551 | rl->lcn = LCN_ENOENT; | |
1552 | /* Reallocate memory if necessary. */ | |
1553 | if (!is_end) { | |
1554 | int new_size = rl - runlist->rl + 1; | |
1555 | rl = ntfs_rl_realloc(runlist->rl, old_size, new_size); | |
1556 | if (IS_ERR(rl)) | |
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."); | |
1562 | else | |
1563 | runlist->rl = rl; | |
1564 | } | |
1565 | } else if (likely(/* !rl->length && */ new_length > rl->vcn)) { | |
1566 | ntfs_debug("Expanding runlist."); | |
1567 | /* | |
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 | |
1570 | * element. | |
1571 | */ | |
1572 | if ((rl > runlist->rl) && ((rl - 1)->lcn == LCN_HOLE)) | |
1573 | (rl - 1)->length = new_length - (rl - 1)->vcn; | |
1574 | else { | |
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, | |
1579 | old_size + 1); | |
1580 | if (IS_ERR(rl)) { | |
1581 | ntfs_error(vol->sb, "Failed to expand runlist " | |
1582 | "buffer, aborting."); | |
1583 | return PTR_ERR(rl); | |
1584 | } | |
1585 | runlist->rl = rl; | |
1586 | /* | |
1587 | * Set @rl to the same runlist element in the new | |
1588 | * runlist as before in the old runlist. | |
1589 | */ | |
1590 | rl += old_size - 1; | |
1591 | /* Add a new, sparse runlist element. */ | |
1592 | rl->lcn = LCN_HOLE; | |
1593 | rl->length = new_length - rl->vcn; | |
1594 | /* Add a new terminator runlist element. */ | |
1595 | rl++; | |
1596 | rl->length = 0; | |
1597 | } | |
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; | |
1603 | } | |
1604 | ntfs_debug("Done."); | |
1605 | return 0; | |
1606 | } | |
53d59aad | 1607 | |
6e48321a AA |
1608 | /** |
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 | |
1614 | * | |
1615 | * Punch a hole into the runlist @runlist starting at VCN @start and of size | |
1616 | * @length clusters. | |
1617 | * | |
1618 | * Return 0 on success and -errno on error, in which case @runlist has not been | |
1619 | * modified. | |
1620 | * | |
1621 | * If @start and/or @start + @length are outside the runlist return error code | |
1622 | * -ENOENT. | |
1623 | * | |
1624 | * If the runlist contains unmapped or error elements between @start and @start | |
1625 | * + @length return error code -EINVAL. | |
1626 | * | |
1627 | * Locking: The caller must hold @runlist->lock for writing. | |
1628 | */ | |
1629 | int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist, | |
1630 | const VCN start, const s64 length) | |
1631 | { | |
1632 | const VCN end = start + length; | |
1633 | s64 delta; | |
1634 | runlist_element *rl, *rl_end, *rl_real_end, *trl; | |
1635 | int old_size; | |
1636 | BOOL lcn_fixup = FALSE; | |
1637 | ||
1638 | ntfs_debug("Entering for start 0x%llx, length 0x%llx.", | |
1639 | (long long)start, (long long)length); | |
1640 | BUG_ON(!runlist); | |
1641 | BUG_ON(start < 0); | |
1642 | BUG_ON(length < 0); | |
1643 | BUG_ON(end < 0); | |
1644 | rl = runlist->rl; | |
1645 | if (unlikely(!rl)) { | |
1646 | if (likely(!start && !length)) | |
1647 | return 0; | |
1648 | return -ENOENT; | |
1649 | } | |
1650 | /* Find @start in the runlist. */ | |
1651 | while (likely(rl->length && start >= rl[1].vcn)) | |
1652 | rl++; | |
1653 | rl_end = rl; | |
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)) | |
1658 | return -EINVAL; | |
1659 | rl_end++; | |
1660 | } | |
1661 | /* Check the last element. */ | |
1662 | if (unlikely(rl_end->length && rl_end->lcn < LCN_HOLE)) | |
1663 | return -EINVAL; | |
1664 | /* This covers @start being out of bounds, too. */ | |
1665 | if (!rl_end->length && end > rl_end->vcn) | |
1666 | return -ENOENT; | |
1667 | if (!length) | |
1668 | return 0; | |
1669 | if (!rl->length) | |
1670 | return -ENOENT; | |
1671 | rl_real_end = rl_end; | |
1672 | /* Determine the runlist size. */ | |
1673 | while (likely(rl_real_end->length)) | |
1674 | rl_real_end++; | |
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) { | |
1678 | /* | |
1679 | * If both @start and @end are in the same sparse run, we are | |
1680 | * done. | |
1681 | */ | |
1682 | if (end <= rl[1].vcn) { | |
1683 | ntfs_debug("Done (requested hole is already sparse)."); | |
1684 | return 0; | |
1685 | } | |
1686 | extend_hole: | |
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) { | |
1691 | rl_end++; | |
1692 | rl->length = rl_end->vcn - rl->vcn; | |
1693 | } | |
1694 | /* We have done the hole. Now deal with the remaining tail. */ | |
1695 | rl++; | |
1696 | /* Cut out all runlist elements up to @end. */ | |
1697 | if (rl < rl_end) | |
1698 | memmove(rl, rl_end, (rl_real_end - rl_end + 1) * | |
1699 | sizeof(*rl)); | |
1700 | /* Adjust the beginning of the tail if necessary. */ | |
1701 | if (end > rl->vcn) { | |
1702 | s64 delta = end - rl->vcn; | |
1703 | rl->vcn = end; | |
1704 | rl->length -= delta; | |
1705 | /* Only adjust the lcn if it is real. */ | |
1706 | if (rl->lcn >= 0) | |
1707 | rl->lcn += delta; | |
1708 | } | |
1709 | shrink_allocation: | |
1710 | /* Reallocate memory if the allocation changed. */ | |
1711 | if (rl < rl_end) { | |
1712 | rl = ntfs_rl_realloc(runlist->rl, old_size, | |
1713 | old_size - (rl_end - rl)); | |
1714 | if (IS_ERR(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."); | |
1720 | else | |
1721 | runlist->rl = rl; | |
1722 | } | |
1723 | ntfs_debug("Done (extend hole)."); | |
1724 | return 0; | |
1725 | } | |
1726 | /* | |
1727 | * If @start is at the beginning of a run things are easier as there is | |
1728 | * no need to split the first run. | |
1729 | */ | |
1730 | if (start == rl->vcn) { | |
1731 | /* | |
1732 | * @start is at the beginning of a run. | |
1733 | * | |
1734 | * If the previous run is sparse, extend its hole. | |
1735 | * | |
1736 | * If @end is not in the same run, switch the run to be sparse | |
1737 | * and extend the newly created hole. | |
1738 | * | |
1739 | * Thus both of these cases reduce the problem to the above | |
1740 | * case of "@start is in a hole". | |
1741 | */ | |
1742 | if (rl > runlist->rl && (rl - 1)->lcn == LCN_HOLE) { | |
1743 | rl--; | |
1744 | goto extend_hole; | |
1745 | } | |
1746 | if (end >= rl[1].vcn) { | |
1747 | rl->lcn = LCN_HOLE; | |
1748 | goto extend_hole; | |
1749 | } | |
1750 | /* | |
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. | |
1756 | */ | |
1757 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); | |
1758 | if (IS_ERR(trl)) | |
1759 | goto enomem_out; | |
1760 | old_size++; | |
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); | |
1765 | runlist->rl = trl; | |
1766 | } | |
1767 | split_end: | |
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. */ | |
1771 | rl->lcn = LCN_HOLE; | |
1772 | rl->length = length; | |
1773 | rl++; | |
1774 | rl->vcn += length; | |
1775 | /* Only adjust the lcn if it is real. */ | |
1776 | if (rl->lcn >= 0 || lcn_fixup) | |
1777 | rl->lcn += length; | |
1778 | rl->length -= length; | |
1779 | ntfs_debug("Done (split one)."); | |
1780 | return 0; | |
1781 | } | |
1782 | /* | |
1783 | * @start is neither in a hole nor at the beginning of a run. | |
1784 | * | |
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. | |
1789 | */ | |
1790 | if (rl_end->lcn == LCN_HOLE) { | |
1791 | /* Truncate the run containing @start. */ | |
1792 | rl->length = start - rl->vcn; | |
1793 | rl++; | |
1794 | /* Cut out all runlist elements up to @end. */ | |
1795 | if (rl < rl_end) | |
1796 | memmove(rl, rl_end, (rl_real_end - rl_end + 1) * | |
1797 | sizeof(*rl)); | |
1798 | /* Extend the beginning of the run @end is in to be @start. */ | |
1799 | rl->vcn = start; | |
1800 | rl->length = rl[1].vcn - start; | |
1801 | goto shrink_allocation; | |
1802 | } | |
1803 | /* | |
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. | |
1806 | * | |
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". | |
1813 | */ | |
1814 | if (end >= rl[1].vcn) { | |
1815 | /* | |
1816 | * If @end is not in the next run, reduce the problem to the | |
1817 | * case of "@start is in a hole". | |
1818 | */ | |
1819 | if (rl[1].length && end >= rl[2].vcn) { | |
1820 | /* Truncate the run containing @start. */ | |
1821 | rl->length = start - rl->vcn; | |
1822 | rl++; | |
1823 | rl->vcn = start; | |
1824 | rl->lcn = LCN_HOLE; | |
1825 | goto extend_hole; | |
1826 | } | |
1827 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); | |
1828 | if (IS_ERR(trl)) | |
1829 | goto enomem_out; | |
1830 | old_size++; | |
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); | |
1835 | runlist->rl = trl; | |
1836 | } | |
1837 | /* Truncate the run containing @start. */ | |
1838 | rl->length = start - rl->vcn; | |
1839 | rl++; | |
1840 | /* | |
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". | |
1844 | */ | |
1845 | delta = rl->vcn - start; | |
1846 | rl->vcn = start; | |
1847 | if (rl->lcn >= 0) { | |
1848 | rl->lcn -= delta; | |
1849 | /* Need this in case the lcn just became negative. */ | |
1850 | lcn_fixup = TRUE; | |
1851 | } | |
1852 | rl->length += delta; | |
1853 | goto split_end; | |
1854 | } | |
1855 | /* | |
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. | |
1861 | */ | |
1862 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 2); | |
1863 | if (IS_ERR(trl)) | |
1864 | goto enomem_out; | |
1865 | 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); | |
1870 | runlist->rl = trl; | |
1871 | } | |
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; | |
1876 | rl++; | |
1877 | rl->vcn = start; | |
1878 | rl->lcn = LCN_HOLE; | |
1879 | rl->length = length; | |
1880 | rl++; | |
1881 | delta = end - rl->vcn; | |
1882 | rl->vcn = end; | |
1883 | rl->lcn += delta; | |
1884 | rl->length -= delta; | |
1885 | ntfs_debug("Done (split both)."); | |
1886 | return 0; | |
1887 | enomem_out: | |
1888 | ntfs_error(vol->sb, "Not enough memory to extend runlist buffer."); | |
1889 | return -ENOMEM; | |
1890 | } | |
1891 | ||
53d59aad | 1892 | #endif /* NTFS_RW */ |