Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /** |
| 2 | * runlist.c - NTFS runlist handling code. Part of the Linux-NTFS project. |
| 3 | * |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 4 | * Copyright (c) 2001-2005 Anton Altaparmakov |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 5 | * Copyright (c) 2002-2005 Richard Russon |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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))) |
Anton Altaparmakov | 9529d46 | 2005-09-08 16:33:12 +0100 | [diff] [blame] | 38 | memmove(base + dst, base + src, size * sizeof(*base)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 62 | * memory, this function returns an entire page of memory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
| 97 | /** |
Anton Altaparmakov | 9529d46 | 2005-09-08 16:33:12 +0100 | [diff] [blame] | 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 | |
| 142 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 161 | /* We can merge unmapped regions even if they are misaligned. */ |
| 162 | if ((dst->lcn == LCN_RL_NOT_MAPPED) && (src->lcn == LCN_RL_NOT_MAPPED)) |
| 163 | return TRUE; |
| 164 | /* If the runs are misaligned, we cannot merge them. */ |
| 165 | if ((dst->vcn + dst->length) != src->vcn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | return FALSE; |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 167 | /* If both runs are non-sparse and contiguous, we can merge them. */ |
| 168 | if ((dst->lcn >= 0) && (src->lcn >= 0) && |
| 169 | ((dst->lcn + dst->length) == src->lcn)) |
| 170 | return TRUE; |
| 171 | /* If we are merging two holes, we can merge them. */ |
| 172 | if ((dst->lcn == LCN_HOLE) && (src->lcn == LCN_HOLE)) |
| 173 | return TRUE; |
| 174 | /* Cannot merge. */ |
| 175 | return FALSE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | } |
| 177 | |
| 178 | /** |
| 179 | * __ntfs_rl_merge - merge two runlists without testing if they can be merged |
| 180 | * @dst: original, destination runlist |
| 181 | * @src: new runlist to merge with @dst |
| 182 | * |
| 183 | * Merge the two runlists, writing into the destination runlist @dst. The |
| 184 | * caller must make sure the runlists can be merged or this will corrupt the |
| 185 | * destination runlist. |
| 186 | * |
| 187 | * It is up to the caller to serialize access to the runlists @dst and @src. |
| 188 | */ |
| 189 | static inline void __ntfs_rl_merge(runlist_element *dst, runlist_element *src) |
| 190 | { |
| 191 | dst->length += src->length; |
| 192 | } |
| 193 | |
| 194 | /** |
| 195 | * ntfs_rl_append - append a runlist after a given element |
| 196 | * @dst: original runlist to be worked on |
| 197 | * @dsize: number of elements in @dst (including end marker) |
| 198 | * @src: runlist to be inserted into @dst |
| 199 | * @ssize: number of elements in @src (excluding end marker) |
| 200 | * @loc: append the new runlist @src after this element in @dst |
| 201 | * |
| 202 | * Append the runlist @src after element @loc in @dst. Merge the right end of |
| 203 | * the new runlist, if necessary. Adjust the size of the hole before the |
| 204 | * appended runlist. |
| 205 | * |
| 206 | * It is up to the caller to serialize access to the runlists @dst and @src. |
| 207 | * |
| 208 | * On success, return a pointer to the new, combined, runlist. Note, both |
| 209 | * runlists @dst and @src are deallocated before returning so you cannot use |
| 210 | * the pointers for anything any more. (Strictly speaking the returned runlist |
| 211 | * may be the same as @dst but this is irrelevant.) |
| 212 | * |
| 213 | * On error, return -errno. Both runlists are left unmodified. The following |
| 214 | * error codes are defined: |
| 215 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 216 | * -EINVAL - Invalid parameters were passed in. |
| 217 | */ |
| 218 | static inline runlist_element *ntfs_rl_append(runlist_element *dst, |
| 219 | int dsize, runlist_element *src, int ssize, int loc) |
| 220 | { |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 221 | BOOL right = FALSE; /* Right end of @src needs merging. */ |
| 222 | int marker; /* End of the inserted runs. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | |
| 224 | BUG_ON(!dst); |
| 225 | BUG_ON(!src); |
| 226 | |
| 227 | /* First, check if the right hand end needs merging. */ |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 228 | if ((loc + 1) < dsize) |
| 229 | right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | |
| 231 | /* Space required: @dst size + @src size, less one if we merged. */ |
| 232 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - right); |
| 233 | if (IS_ERR(dst)) |
| 234 | return dst; |
| 235 | /* |
| 236 | * We are guaranteed to succeed from here so can start modifying the |
| 237 | * original runlists. |
| 238 | */ |
| 239 | |
| 240 | /* First, merge the right hand end, if necessary. */ |
| 241 | if (right) |
| 242 | __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); |
| 243 | |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 244 | /* First run after the @src runs that have been inserted. */ |
| 245 | marker = loc + ssize + 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 246 | |
| 247 | /* Move the tail of @dst out of the way, then copy in @src. */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 248 | ntfs_rl_mm(dst, marker, loc + 1 + right, dsize - (loc + 1 + right)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | ntfs_rl_mc(dst, loc + 1, src, 0, ssize); |
| 250 | |
| 251 | /* Adjust the size of the preceding hole. */ |
| 252 | dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; |
| 253 | |
| 254 | /* We may have changed the length of the file, so fix the end marker */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 255 | if (dst[marker].lcn == LCN_ENOENT) |
| 256 | dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
| 258 | return dst; |
| 259 | } |
| 260 | |
| 261 | /** |
| 262 | * ntfs_rl_insert - insert a runlist into another |
| 263 | * @dst: original runlist to be worked on |
| 264 | * @dsize: number of elements in @dst (including end marker) |
| 265 | * @src: new runlist to be inserted |
| 266 | * @ssize: number of elements in @src (excluding end marker) |
| 267 | * @loc: insert the new runlist @src before this element in @dst |
| 268 | * |
| 269 | * Insert the runlist @src before element @loc in the runlist @dst. Merge the |
| 270 | * left end of the new runlist, if necessary. Adjust the size of the hole |
| 271 | * after the inserted runlist. |
| 272 | * |
| 273 | * It is up to the caller to serialize access to the runlists @dst and @src. |
| 274 | * |
| 275 | * On success, return a pointer to the new, combined, runlist. Note, both |
| 276 | * runlists @dst and @src are deallocated before returning so you cannot use |
| 277 | * the pointers for anything any more. (Strictly speaking the returned runlist |
| 278 | * may be the same as @dst but this is irrelevant.) |
| 279 | * |
| 280 | * On error, return -errno. Both runlists are left unmodified. The following |
| 281 | * error codes are defined: |
| 282 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 283 | * -EINVAL - Invalid parameters were passed in. |
| 284 | */ |
| 285 | static inline runlist_element *ntfs_rl_insert(runlist_element *dst, |
| 286 | int dsize, runlist_element *src, int ssize, int loc) |
| 287 | { |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 288 | BOOL left = FALSE; /* Left end of @src needs merging. */ |
| 289 | BOOL disc = FALSE; /* Discontinuity between @dst and @src. */ |
| 290 | int marker; /* End of the inserted runs. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | |
| 292 | BUG_ON(!dst); |
| 293 | BUG_ON(!src); |
| 294 | |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 295 | /* |
| 296 | * disc => Discontinuity between the end of @dst and the start of @src. |
| 297 | * This means we might need to insert a "not mapped" run. |
| 298 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | if (loc == 0) |
| 300 | disc = (src[0].vcn > 0); |
| 301 | else { |
| 302 | s64 merged_length; |
| 303 | |
| 304 | left = ntfs_are_rl_mergeable(dst + loc - 1, src); |
| 305 | |
| 306 | merged_length = dst[loc - 1].length; |
| 307 | if (left) |
| 308 | merged_length += src->length; |
| 309 | |
| 310 | disc = (src[0].vcn > dst[loc - 1].vcn + merged_length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 311 | } |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 312 | /* |
| 313 | * Space required: @dst size + @src size, less one if we merged, plus |
| 314 | * one if there was a discontinuity. |
| 315 | */ |
| 316 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left + disc); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | if (IS_ERR(dst)) |
| 318 | return dst; |
| 319 | /* |
| 320 | * We are guaranteed to succeed from here so can start modifying the |
| 321 | * original runlist. |
| 322 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | if (left) |
| 324 | __ntfs_rl_merge(dst + loc - 1, src); |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 325 | /* |
| 326 | * First run after the @src runs that have been inserted. |
| 327 | * Nominally, @marker equals @loc + @ssize, i.e. location + number of |
| 328 | * runs in @src. However, if @left, then the first run in @src has |
| 329 | * been merged with one in @dst. And if @disc, then @dst and @src do |
| 330 | * not meet and we need an extra run to fill the gap. |
| 331 | */ |
| 332 | marker = loc + ssize - left + disc; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | |
| 334 | /* Move the tail of @dst out of the way, then copy in @src. */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 335 | ntfs_rl_mm(dst, marker, loc, dsize - loc); |
| 336 | ntfs_rl_mc(dst, loc + disc, src, left, ssize - left); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 338 | /* Adjust the VCN of the first run after the insertion... */ |
| 339 | dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | /* ... and the length. */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 341 | if (dst[marker].lcn == LCN_HOLE || dst[marker].lcn == LCN_RL_NOT_MAPPED) |
| 342 | dst[marker].length = dst[marker + 1].vcn - dst[marker].vcn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 344 | /* Writing beyond the end of the file and there is a discontinuity. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 345 | if (disc) { |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 346 | if (loc > 0) { |
| 347 | dst[loc].vcn = dst[loc - 1].vcn + dst[loc - 1].length; |
| 348 | dst[loc].length = dst[loc + 1].vcn - dst[loc].vcn; |
| 349 | } else { |
| 350 | dst[loc].vcn = 0; |
| 351 | dst[loc].length = dst[loc + 1].vcn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | } |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 353 | dst[loc].lcn = LCN_RL_NOT_MAPPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 354 | } |
| 355 | return dst; |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * ntfs_rl_replace - overwrite a runlist element with another runlist |
| 360 | * @dst: original runlist to be worked on |
| 361 | * @dsize: number of elements in @dst (including end marker) |
| 362 | * @src: new runlist to be inserted |
| 363 | * @ssize: number of elements in @src (excluding end marker) |
| 364 | * @loc: index in runlist @dst to overwrite with @src |
| 365 | * |
| 366 | * Replace the runlist element @dst at @loc with @src. Merge the left and |
| 367 | * right ends of the inserted runlist, if necessary. |
| 368 | * |
| 369 | * It is up to the caller to serialize access to the runlists @dst and @src. |
| 370 | * |
| 371 | * On success, return a pointer to the new, combined, runlist. Note, both |
| 372 | * runlists @dst and @src are deallocated before returning so you cannot use |
| 373 | * the pointers for anything any more. (Strictly speaking the returned runlist |
| 374 | * may be the same as @dst but this is irrelevant.) |
| 375 | * |
| 376 | * On error, return -errno. Both runlists are left unmodified. The following |
| 377 | * error codes are defined: |
| 378 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 379 | * -EINVAL - Invalid parameters were passed in. |
| 380 | */ |
| 381 | static inline runlist_element *ntfs_rl_replace(runlist_element *dst, |
| 382 | int dsize, runlist_element *src, int ssize, int loc) |
| 383 | { |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 384 | BOOL left = FALSE; /* Left end of @src needs merging. */ |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 385 | BOOL right = FALSE; /* Right end of @src needs merging. */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 386 | int tail; /* Start of tail of @dst. */ |
| 387 | int marker; /* End of the inserted runs. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | |
| 389 | BUG_ON(!dst); |
| 390 | BUG_ON(!src); |
| 391 | |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 392 | /* First, see if the left and right ends need merging. */ |
| 393 | if ((loc + 1) < dsize) |
| 394 | right = ntfs_are_rl_mergeable(src + ssize - 1, dst + loc + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 395 | if (loc > 0) |
| 396 | left = ntfs_are_rl_mergeable(dst + loc - 1, src); |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 397 | /* |
| 398 | * Allocate some space. We will need less if the left, right, or both |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 399 | * ends get merged. |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 400 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize - left - right); |
| 402 | if (IS_ERR(dst)) |
| 403 | return dst; |
| 404 | /* |
| 405 | * We are guaranteed to succeed from here so can start modifying the |
| 406 | * original runlists. |
| 407 | */ |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 408 | |
| 409 | /* First, merge the left and right ends, if necessary. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 410 | if (right) |
| 411 | __ntfs_rl_merge(src + ssize - 1, dst + loc + 1); |
| 412 | if (left) |
| 413 | __ntfs_rl_merge(dst + loc - 1, src); |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 414 | /* |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 415 | * Offset of the tail of @dst. This needs to be moved out of the way |
| 416 | * to make space for the runs to be copied from @src, i.e. the first |
| 417 | * run of the tail of @dst. |
| 418 | * Nominally, @tail equals @loc + 1, i.e. location, skipping the |
| 419 | * replaced run. However, if @right, then one of @dst's runs is |
| 420 | * already merged into @src. |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 421 | */ |
| 422 | tail = loc + right + 1; |
| 423 | /* |
| 424 | * First run after the @src runs that have been inserted, i.e. where |
| 425 | * the tail of @dst needs to be moved to. |
Anton Altaparmakov | eed8b2d | 2005-09-20 14:19:30 +0100 | [diff] [blame] | 426 | * Nominally, @marker equals @loc + @ssize, i.e. location + number of |
| 427 | * runs in @src. However, if @left, then the first run in @src has |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 428 | * been merged with one in @dst. |
| 429 | */ |
| 430 | marker = loc + ssize - left; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | |
| 432 | /* Move the tail of @dst out of the way, then copy in @src. */ |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 433 | ntfs_rl_mm(dst, marker, tail, dsize - tail); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 434 | ntfs_rl_mc(dst, loc, src, left, ssize - left); |
| 435 | |
Anton Altaparmakov | 5c9f6de | 2005-09-19 09:33:40 +0100 | [diff] [blame] | 436 | /* We may have changed the length of the file, so fix the end marker. */ |
| 437 | if (dsize - tail > 0 && dst[marker].lcn == LCN_ENOENT) |
| 438 | dst[marker].vcn = dst[marker - 1].vcn + dst[marker - 1].length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 439 | return dst; |
| 440 | } |
| 441 | |
| 442 | /** |
| 443 | * ntfs_rl_split - insert a runlist into the centre of a hole |
| 444 | * @dst: original runlist to be worked on |
| 445 | * @dsize: number of elements in @dst (including end marker) |
| 446 | * @src: new runlist to be inserted |
| 447 | * @ssize: number of elements in @src (excluding end marker) |
| 448 | * @loc: index in runlist @dst at which to split and insert @src |
| 449 | * |
| 450 | * Split the runlist @dst at @loc into two and insert @new in between the two |
| 451 | * fragments. No merging of runlists is necessary. Adjust the size of the |
| 452 | * holes either side. |
| 453 | * |
| 454 | * It is up to the caller to serialize access to the runlists @dst and @src. |
| 455 | * |
| 456 | * On success, return a pointer to the new, combined, runlist. Note, both |
| 457 | * runlists @dst and @src are deallocated before returning so you cannot use |
| 458 | * the pointers for anything any more. (Strictly speaking the returned runlist |
| 459 | * may be the same as @dst but this is irrelevant.) |
| 460 | * |
| 461 | * On error, return -errno. Both runlists are left unmodified. The following |
| 462 | * error codes are defined: |
| 463 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 464 | * -EINVAL - Invalid parameters were passed in. |
| 465 | */ |
| 466 | static inline runlist_element *ntfs_rl_split(runlist_element *dst, int dsize, |
| 467 | runlist_element *src, int ssize, int loc) |
| 468 | { |
| 469 | BUG_ON(!dst); |
| 470 | BUG_ON(!src); |
| 471 | |
| 472 | /* Space required: @dst size + @src size + one new hole. */ |
| 473 | dst = ntfs_rl_realloc(dst, dsize, dsize + ssize + 1); |
| 474 | if (IS_ERR(dst)) |
| 475 | return dst; |
| 476 | /* |
| 477 | * We are guaranteed to succeed from here so can start modifying the |
| 478 | * original runlists. |
| 479 | */ |
| 480 | |
| 481 | /* Move the tail of @dst out of the way, then copy in @src. */ |
| 482 | ntfs_rl_mm(dst, loc + 1 + ssize, loc, dsize - loc); |
| 483 | ntfs_rl_mc(dst, loc + 1, src, 0, ssize); |
| 484 | |
| 485 | /* Adjust the size of the holes either size of @src. */ |
| 486 | dst[loc].length = dst[loc+1].vcn - dst[loc].vcn; |
| 487 | dst[loc+ssize+1].vcn = dst[loc+ssize].vcn + dst[loc+ssize].length; |
| 488 | dst[loc+ssize+1].length = dst[loc+ssize+2].vcn - dst[loc+ssize+1].vcn; |
| 489 | |
| 490 | return dst; |
| 491 | } |
| 492 | |
| 493 | /** |
| 494 | * ntfs_runlists_merge - merge two runlists into one |
| 495 | * @drl: original runlist to be worked on |
| 496 | * @srl: new runlist to be merged into @drl |
| 497 | * |
| 498 | * First we sanity check the two runlists @srl and @drl to make sure that they |
| 499 | * are sensible and can be merged. The runlist @srl must be either after the |
| 500 | * runlist @drl or completely within a hole (or unmapped region) in @drl. |
| 501 | * |
| 502 | * It is up to the caller to serialize access to the runlists @drl and @srl. |
| 503 | * |
| 504 | * Merging of runlists is necessary in two cases: |
| 505 | * 1. When attribute lists are used and a further extent is being mapped. |
| 506 | * 2. When new clusters are allocated to fill a hole or extend a file. |
| 507 | * |
| 508 | * There are four possible ways @srl can be merged. It can: |
| 509 | * - be inserted at the beginning of a hole, |
| 510 | * - split the hole in two and be inserted between the two fragments, |
| 511 | * - be appended at the end of a hole, or it can |
| 512 | * - replace the whole hole. |
| 513 | * It can also be appended to the end of the runlist, which is just a variant |
| 514 | * of the insert case. |
| 515 | * |
| 516 | * On success, return a pointer to the new, combined, runlist. Note, both |
| 517 | * runlists @drl and @srl are deallocated before returning so you cannot use |
| 518 | * the pointers for anything any more. (Strictly speaking the returned runlist |
| 519 | * may be the same as @dst but this is irrelevant.) |
| 520 | * |
| 521 | * On error, return -errno. Both runlists are left unmodified. The following |
| 522 | * error codes are defined: |
| 523 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 524 | * -EINVAL - Invalid parameters were passed in. |
| 525 | * -ERANGE - The runlists overlap and cannot be merged. |
| 526 | */ |
| 527 | runlist_element *ntfs_runlists_merge(runlist_element *drl, |
| 528 | runlist_element *srl) |
| 529 | { |
| 530 | int di, si; /* Current index into @[ds]rl. */ |
| 531 | int sstart; /* First index with lcn > LCN_RL_NOT_MAPPED. */ |
| 532 | int dins; /* Index into @drl at which to insert @srl. */ |
| 533 | int dend, send; /* Last index into @[ds]rl. */ |
| 534 | int dfinal, sfinal; /* The last index into @[ds]rl with |
| 535 | lcn >= LCN_HOLE. */ |
| 536 | int marker = 0; |
| 537 | VCN marker_vcn = 0; |
| 538 | |
| 539 | #ifdef DEBUG |
| 540 | ntfs_debug("dst:"); |
| 541 | ntfs_debug_dump_runlist(drl); |
| 542 | ntfs_debug("src:"); |
| 543 | ntfs_debug_dump_runlist(srl); |
| 544 | #endif |
| 545 | |
| 546 | /* Check for silly calling... */ |
| 547 | if (unlikely(!srl)) |
| 548 | return drl; |
| 549 | if (IS_ERR(srl) || IS_ERR(drl)) |
| 550 | return ERR_PTR(-EINVAL); |
| 551 | |
| 552 | /* Check for the case where the first mapping is being done now. */ |
| 553 | if (unlikely(!drl)) { |
| 554 | drl = srl; |
| 555 | /* Complete the source runlist if necessary. */ |
| 556 | if (unlikely(drl[0].vcn)) { |
| 557 | /* Scan to the end of the source runlist. */ |
| 558 | for (dend = 0; likely(drl[dend].length); dend++) |
| 559 | ; |
Anton Altaparmakov | 84d6ebe | 2005-09-08 16:46:55 +0100 | [diff] [blame] | 560 | dend++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | drl = ntfs_rl_realloc(drl, dend, dend + 1); |
| 562 | if (IS_ERR(drl)) |
| 563 | return drl; |
| 564 | /* Insert start element at the front of the runlist. */ |
| 565 | ntfs_rl_mm(drl, 1, 0, dend); |
| 566 | drl[0].vcn = 0; |
| 567 | drl[0].lcn = LCN_RL_NOT_MAPPED; |
| 568 | drl[0].length = drl[1].vcn; |
| 569 | } |
| 570 | goto finished; |
| 571 | } |
| 572 | |
| 573 | si = di = 0; |
| 574 | |
| 575 | /* Skip any unmapped start element(s) in the source runlist. */ |
| 576 | while (srl[si].length && srl[si].lcn < LCN_HOLE) |
| 577 | si++; |
| 578 | |
| 579 | /* Can't have an entirely unmapped source runlist. */ |
| 580 | BUG_ON(!srl[si].length); |
| 581 | |
| 582 | /* Record the starting points. */ |
| 583 | sstart = si; |
| 584 | |
| 585 | /* |
| 586 | * Skip forward in @drl until we reach the position where @srl needs to |
| 587 | * be inserted. If we reach the end of @drl, @srl just needs to be |
| 588 | * appended to @drl. |
| 589 | */ |
| 590 | for (; drl[di].length; di++) { |
| 591 | if (drl[di].vcn + drl[di].length > srl[sstart].vcn) |
| 592 | break; |
| 593 | } |
| 594 | dins = di; |
| 595 | |
| 596 | /* Sanity check for illegal overlaps. */ |
| 597 | if ((drl[di].vcn == srl[si].vcn) && (drl[di].lcn >= 0) && |
| 598 | (srl[si].lcn >= 0)) { |
| 599 | ntfs_error(NULL, "Run lists overlap. Cannot merge!"); |
| 600 | return ERR_PTR(-ERANGE); |
| 601 | } |
| 602 | |
| 603 | /* Scan to the end of both runlists in order to know their sizes. */ |
| 604 | for (send = si; srl[send].length; send++) |
| 605 | ; |
| 606 | for (dend = di; drl[dend].length; dend++) |
| 607 | ; |
| 608 | |
| 609 | if (srl[send].lcn == LCN_ENOENT) |
| 610 | marker_vcn = srl[marker = send].vcn; |
| 611 | |
| 612 | /* Scan to the last element with lcn >= LCN_HOLE. */ |
| 613 | for (sfinal = send; sfinal >= 0 && srl[sfinal].lcn < LCN_HOLE; sfinal--) |
| 614 | ; |
| 615 | for (dfinal = dend; dfinal >= 0 && drl[dfinal].lcn < LCN_HOLE; dfinal--) |
| 616 | ; |
| 617 | |
| 618 | { |
| 619 | BOOL start; |
| 620 | BOOL finish; |
| 621 | int ds = dend + 1; /* Number of elements in drl & srl */ |
| 622 | int ss = sfinal - sstart + 1; |
| 623 | |
| 624 | start = ((drl[dins].lcn < LCN_RL_NOT_MAPPED) || /* End of file */ |
| 625 | (drl[dins].vcn == srl[sstart].vcn)); /* Start of hole */ |
| 626 | finish = ((drl[dins].lcn >= LCN_RL_NOT_MAPPED) && /* End of file */ |
| 627 | ((drl[dins].vcn + drl[dins].length) <= /* End of hole */ |
| 628 | (srl[send - 1].vcn + srl[send - 1].length))); |
| 629 | |
Anton Altaparmakov | 84d6ebe | 2005-09-08 16:46:55 +0100 | [diff] [blame] | 630 | /* Or we will lose an end marker. */ |
| 631 | if (finish && !drl[dins].length) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | ss++; |
| 633 | if (marker && (drl[dins].vcn + drl[dins].length > srl[send - 1].vcn)) |
| 634 | finish = FALSE; |
| 635 | #if 0 |
| 636 | ntfs_debug("dfinal = %i, dend = %i", dfinal, dend); |
| 637 | ntfs_debug("sstart = %i, sfinal = %i, send = %i", sstart, sfinal, send); |
| 638 | ntfs_debug("start = %i, finish = %i", start, finish); |
| 639 | ntfs_debug("ds = %i, ss = %i, dins = %i", ds, ss, dins); |
| 640 | #endif |
| 641 | if (start) { |
| 642 | if (finish) |
| 643 | drl = ntfs_rl_replace(drl, ds, srl + sstart, ss, dins); |
| 644 | else |
| 645 | drl = ntfs_rl_insert(drl, ds, srl + sstart, ss, dins); |
| 646 | } else { |
| 647 | if (finish) |
| 648 | drl = ntfs_rl_append(drl, ds, srl + sstart, ss, dins); |
| 649 | else |
| 650 | drl = ntfs_rl_split(drl, ds, srl + sstart, ss, dins); |
| 651 | } |
| 652 | if (IS_ERR(drl)) { |
| 653 | ntfs_error(NULL, "Merge failed."); |
| 654 | return drl; |
| 655 | } |
| 656 | ntfs_free(srl); |
| 657 | if (marker) { |
| 658 | ntfs_debug("Triggering marker code."); |
| 659 | for (ds = dend; drl[ds].length; ds++) |
| 660 | ; |
| 661 | /* We only need to care if @srl ended after @drl. */ |
| 662 | if (drl[ds].vcn <= marker_vcn) { |
| 663 | int slots = 0; |
| 664 | |
| 665 | if (drl[ds].vcn == marker_vcn) { |
| 666 | ntfs_debug("Old marker = 0x%llx, replacing " |
| 667 | "with LCN_ENOENT.", |
| 668 | (unsigned long long) |
| 669 | drl[ds].lcn); |
| 670 | drl[ds].lcn = LCN_ENOENT; |
| 671 | goto finished; |
| 672 | } |
| 673 | /* |
| 674 | * We need to create an unmapped runlist element in |
| 675 | * @drl or extend an existing one before adding the |
| 676 | * ENOENT terminator. |
| 677 | */ |
| 678 | if (drl[ds].lcn == LCN_ENOENT) { |
| 679 | ds--; |
| 680 | slots = 1; |
| 681 | } |
| 682 | if (drl[ds].lcn != LCN_RL_NOT_MAPPED) { |
| 683 | /* Add an unmapped runlist element. */ |
| 684 | if (!slots) { |
Anton Altaparmakov | 9529d46 | 2005-09-08 16:33:12 +0100 | [diff] [blame] | 685 | drl = ntfs_rl_realloc_nofail(drl, ds, |
| 686 | ds + 2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 687 | slots = 2; |
| 688 | } |
| 689 | ds++; |
| 690 | /* Need to set vcn if it isn't set already. */ |
| 691 | if (slots != 1) |
| 692 | drl[ds].vcn = drl[ds - 1].vcn + |
| 693 | drl[ds - 1].length; |
| 694 | drl[ds].lcn = LCN_RL_NOT_MAPPED; |
| 695 | /* We now used up a slot. */ |
| 696 | slots--; |
| 697 | } |
| 698 | drl[ds].length = marker_vcn - drl[ds].vcn; |
| 699 | /* Finally add the ENOENT terminator. */ |
| 700 | ds++; |
Anton Altaparmakov | 9529d46 | 2005-09-08 16:33:12 +0100 | [diff] [blame] | 701 | if (!slots) |
| 702 | drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 703 | drl[ds].vcn = marker_vcn; |
| 704 | drl[ds].lcn = LCN_ENOENT; |
| 705 | drl[ds].length = (s64)0; |
| 706 | } |
| 707 | } |
| 708 | } |
| 709 | |
| 710 | finished: |
| 711 | /* The merge was completed successfully. */ |
| 712 | ntfs_debug("Merged runlist:"); |
| 713 | ntfs_debug_dump_runlist(drl); |
| 714 | return drl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | } |
| 716 | |
| 717 | /** |
| 718 | * ntfs_mapping_pairs_decompress - convert mapping pairs array to runlist |
| 719 | * @vol: ntfs volume on which the attribute resides |
| 720 | * @attr: attribute record whose mapping pairs array to decompress |
| 721 | * @old_rl: optional runlist in which to insert @attr's runlist |
| 722 | * |
| 723 | * It is up to the caller to serialize access to the runlist @old_rl. |
| 724 | * |
| 725 | * Decompress the attribute @attr's mapping pairs array into a runlist. On |
| 726 | * success, return the decompressed runlist. |
| 727 | * |
| 728 | * If @old_rl is not NULL, decompressed runlist is inserted into the |
| 729 | * appropriate place in @old_rl and the resultant, combined runlist is |
| 730 | * returned. The original @old_rl is deallocated. |
| 731 | * |
| 732 | * On error, return -errno. @old_rl is left unmodified in that case. |
| 733 | * |
| 734 | * The following error codes are defined: |
| 735 | * -ENOMEM - Not enough memory to allocate runlist array. |
| 736 | * -EIO - Corrupt runlist. |
| 737 | * -EINVAL - Invalid parameters were passed in. |
| 738 | * -ERANGE - The two runlists overlap. |
| 739 | * |
| 740 | * FIXME: For now we take the conceptionally simplest approach of creating the |
| 741 | * new runlist disregarding the already existing one and then splicing the |
| 742 | * two into one, if that is possible (we check for overlap and discard the new |
| 743 | * runlist if overlap present before returning ERR_PTR(-ERANGE)). |
| 744 | */ |
| 745 | runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol, |
| 746 | const ATTR_RECORD *attr, runlist_element *old_rl) |
| 747 | { |
| 748 | VCN vcn; /* Current vcn. */ |
| 749 | LCN lcn; /* Current lcn. */ |
| 750 | s64 deltaxcn; /* Change in [vl]cn. */ |
| 751 | runlist_element *rl; /* The output runlist. */ |
| 752 | u8 *buf; /* Current position in mapping pairs array. */ |
| 753 | u8 *attr_end; /* End of attribute. */ |
| 754 | int rlsize; /* Size of runlist buffer. */ |
| 755 | u16 rlpos; /* Current runlist position in units of |
| 756 | runlist_elements. */ |
| 757 | u8 b; /* Current byte offset in buf. */ |
| 758 | |
| 759 | #ifdef DEBUG |
| 760 | /* Make sure attr exists and is non-resident. */ |
| 761 | if (!attr || !attr->non_resident || sle64_to_cpu( |
| 762 | attr->data.non_resident.lowest_vcn) < (VCN)0) { |
| 763 | ntfs_error(vol->sb, "Invalid arguments."); |
| 764 | return ERR_PTR(-EINVAL); |
| 765 | } |
| 766 | #endif |
| 767 | /* Start at vcn = lowest_vcn and lcn 0. */ |
| 768 | vcn = sle64_to_cpu(attr->data.non_resident.lowest_vcn); |
| 769 | lcn = 0; |
| 770 | /* Get start of the mapping pairs array. */ |
| 771 | buf = (u8*)attr + le16_to_cpu( |
| 772 | attr->data.non_resident.mapping_pairs_offset); |
| 773 | attr_end = (u8*)attr + le32_to_cpu(attr->length); |
| 774 | if (unlikely(buf < (u8*)attr || buf > attr_end)) { |
| 775 | ntfs_error(vol->sb, "Corrupt attribute."); |
| 776 | return ERR_PTR(-EIO); |
| 777 | } |
Anton Altaparmakov | 2b0ada2 | 2005-09-08 16:52:31 +0100 | [diff] [blame] | 778 | /* If the mapping pairs array is valid but empty, nothing to do. */ |
| 779 | if (!vcn && !*buf) |
| 780 | return old_rl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | /* Current position in runlist array. */ |
| 782 | rlpos = 0; |
| 783 | /* Allocate first page and set current runlist size to one page. */ |
| 784 | rl = ntfs_malloc_nofs(rlsize = PAGE_SIZE); |
| 785 | if (unlikely(!rl)) |
| 786 | return ERR_PTR(-ENOMEM); |
| 787 | /* Insert unmapped starting element if necessary. */ |
| 788 | if (vcn) { |
| 789 | rl->vcn = 0; |
| 790 | rl->lcn = LCN_RL_NOT_MAPPED; |
| 791 | rl->length = vcn; |
| 792 | rlpos++; |
| 793 | } |
| 794 | while (buf < attr_end && *buf) { |
| 795 | /* |
| 796 | * Allocate more memory if needed, including space for the |
| 797 | * not-mapped and terminator elements. ntfs_malloc_nofs() |
| 798 | * operates on whole pages only. |
| 799 | */ |
| 800 | if (((rlpos + 3) * sizeof(*old_rl)) > rlsize) { |
| 801 | runlist_element *rl2; |
| 802 | |
| 803 | rl2 = ntfs_malloc_nofs(rlsize + (int)PAGE_SIZE); |
| 804 | if (unlikely(!rl2)) { |
| 805 | ntfs_free(rl); |
| 806 | return ERR_PTR(-ENOMEM); |
| 807 | } |
| 808 | memcpy(rl2, rl, rlsize); |
| 809 | ntfs_free(rl); |
| 810 | rl = rl2; |
| 811 | rlsize += PAGE_SIZE; |
| 812 | } |
| 813 | /* Enter the current vcn into the current runlist element. */ |
| 814 | rl[rlpos].vcn = vcn; |
| 815 | /* |
| 816 | * Get the change in vcn, i.e. the run length in clusters. |
| 817 | * Doing it this way ensures that we signextend negative values. |
| 818 | * A negative run length doesn't make any sense, but hey, I |
| 819 | * didn't make up the NTFS specs and Windows NT4 treats the run |
| 820 | * length as a signed value so that's how it is... |
| 821 | */ |
| 822 | b = *buf & 0xf; |
| 823 | if (b) { |
| 824 | if (unlikely(buf + b > attr_end)) |
| 825 | goto io_error; |
| 826 | for (deltaxcn = (s8)buf[b--]; b; b--) |
| 827 | deltaxcn = (deltaxcn << 8) + buf[b]; |
| 828 | } else { /* The length entry is compulsory. */ |
| 829 | ntfs_error(vol->sb, "Missing length entry in mapping " |
| 830 | "pairs array."); |
| 831 | deltaxcn = (s64)-1; |
| 832 | } |
| 833 | /* |
| 834 | * Assume a negative length to indicate data corruption and |
| 835 | * hence clean-up and return NULL. |
| 836 | */ |
| 837 | if (unlikely(deltaxcn < 0)) { |
| 838 | ntfs_error(vol->sb, "Invalid length in mapping pairs " |
| 839 | "array."); |
| 840 | goto err_out; |
| 841 | } |
| 842 | /* |
| 843 | * Enter the current run length into the current runlist |
| 844 | * element. |
| 845 | */ |
| 846 | rl[rlpos].length = deltaxcn; |
| 847 | /* Increment the current vcn by the current run length. */ |
| 848 | vcn += deltaxcn; |
| 849 | /* |
| 850 | * There might be no lcn change at all, as is the case for |
| 851 | * sparse clusters on NTFS 3.0+, in which case we set the lcn |
| 852 | * to LCN_HOLE. |
| 853 | */ |
| 854 | if (!(*buf & 0xf0)) |
| 855 | rl[rlpos].lcn = LCN_HOLE; |
| 856 | else { |
| 857 | /* Get the lcn change which really can be negative. */ |
| 858 | u8 b2 = *buf & 0xf; |
| 859 | b = b2 + ((*buf >> 4) & 0xf); |
| 860 | if (buf + b > attr_end) |
| 861 | goto io_error; |
| 862 | for (deltaxcn = (s8)buf[b--]; b > b2; b--) |
| 863 | deltaxcn = (deltaxcn << 8) + buf[b]; |
| 864 | /* Change the current lcn to its new value. */ |
| 865 | lcn += deltaxcn; |
| 866 | #ifdef DEBUG |
| 867 | /* |
| 868 | * On NTFS 1.2-, apparently can have lcn == -1 to |
| 869 | * indicate a hole. But we haven't verified ourselves |
| 870 | * whether it is really the lcn or the deltaxcn that is |
| 871 | * -1. So if either is found give us a message so we |
| 872 | * can investigate it further! |
| 873 | */ |
| 874 | if (vol->major_ver < 3) { |
| 875 | if (unlikely(deltaxcn == (LCN)-1)) |
| 876 | ntfs_error(vol->sb, "lcn delta == -1"); |
| 877 | if (unlikely(lcn == (LCN)-1)) |
| 878 | ntfs_error(vol->sb, "lcn == -1"); |
| 879 | } |
| 880 | #endif |
| 881 | /* Check lcn is not below -1. */ |
| 882 | if (unlikely(lcn < (LCN)-1)) { |
| 883 | ntfs_error(vol->sb, "Invalid LCN < -1 in " |
| 884 | "mapping pairs array."); |
| 885 | goto err_out; |
| 886 | } |
| 887 | /* Enter the current lcn into the runlist element. */ |
| 888 | rl[rlpos].lcn = lcn; |
| 889 | } |
| 890 | /* Get to the next runlist element. */ |
| 891 | rlpos++; |
| 892 | /* Increment the buffer position to the next mapping pair. */ |
| 893 | buf += (*buf & 0xf) + ((*buf >> 4) & 0xf) + 1; |
| 894 | } |
| 895 | if (unlikely(buf >= attr_end)) |
| 896 | goto io_error; |
| 897 | /* |
| 898 | * If there is a highest_vcn specified, it must be equal to the final |
| 899 | * vcn in the runlist - 1, or something has gone badly wrong. |
| 900 | */ |
| 901 | deltaxcn = sle64_to_cpu(attr->data.non_resident.highest_vcn); |
| 902 | if (unlikely(deltaxcn && vcn - 1 != deltaxcn)) { |
| 903 | mpa_err: |
| 904 | ntfs_error(vol->sb, "Corrupt mapping pairs array in " |
| 905 | "non-resident attribute."); |
| 906 | goto err_out; |
| 907 | } |
| 908 | /* Setup not mapped runlist element if this is the base extent. */ |
| 909 | if (!attr->data.non_resident.lowest_vcn) { |
| 910 | VCN max_cluster; |
| 911 | |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 912 | max_cluster = ((sle64_to_cpu( |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | attr->data.non_resident.allocated_size) + |
| 914 | vol->cluster_size - 1) >> |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 915 | vol->cluster_size_bits) - 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 916 | /* |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 917 | * A highest_vcn of zero means this is a single extent |
| 918 | * attribute so simply terminate the runlist with LCN_ENOENT). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 919 | */ |
Anton Altaparmakov | 1a0df15 | 2005-02-03 12:04:36 +0000 | [diff] [blame] | 920 | if (deltaxcn) { |
| 921 | /* |
| 922 | * If there is a difference between the highest_vcn and |
| 923 | * the highest cluster, the runlist is either corrupt |
| 924 | * or, more likely, there are more extents following |
| 925 | * this one. |
| 926 | */ |
| 927 | if (deltaxcn < max_cluster) { |
| 928 | ntfs_debug("More extents to follow; deltaxcn " |
| 929 | "= 0x%llx, max_cluster = " |
| 930 | "0x%llx", |
| 931 | (unsigned long long)deltaxcn, |
| 932 | (unsigned long long) |
| 933 | max_cluster); |
| 934 | rl[rlpos].vcn = vcn; |
| 935 | vcn += rl[rlpos].length = max_cluster - |
| 936 | deltaxcn; |
| 937 | rl[rlpos].lcn = LCN_RL_NOT_MAPPED; |
| 938 | rlpos++; |
| 939 | } else if (unlikely(deltaxcn > max_cluster)) { |
| 940 | ntfs_error(vol->sb, "Corrupt attribute. " |
| 941 | "deltaxcn = 0x%llx, " |
| 942 | "max_cluster = 0x%llx", |
| 943 | (unsigned long long)deltaxcn, |
| 944 | (unsigned long long) |
| 945 | max_cluster); |
| 946 | goto mpa_err; |
| 947 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 948 | } |
| 949 | rl[rlpos].lcn = LCN_ENOENT; |
| 950 | } else /* Not the base extent. There may be more extents to follow. */ |
| 951 | rl[rlpos].lcn = LCN_RL_NOT_MAPPED; |
| 952 | |
| 953 | /* Setup terminating runlist element. */ |
| 954 | rl[rlpos].vcn = vcn; |
| 955 | rl[rlpos].length = (s64)0; |
| 956 | /* If no existing runlist was specified, we are done. */ |
| 957 | if (!old_rl) { |
| 958 | ntfs_debug("Mapping pairs array successfully decompressed:"); |
| 959 | ntfs_debug_dump_runlist(rl); |
| 960 | return rl; |
| 961 | } |
| 962 | /* Now combine the new and old runlists checking for overlaps. */ |
| 963 | old_rl = ntfs_runlists_merge(old_rl, rl); |
| 964 | if (likely(!IS_ERR(old_rl))) |
| 965 | return old_rl; |
| 966 | ntfs_free(rl); |
| 967 | ntfs_error(vol->sb, "Failed to merge runlists."); |
| 968 | return old_rl; |
| 969 | io_error: |
| 970 | ntfs_error(vol->sb, "Corrupt attribute."); |
| 971 | err_out: |
| 972 | ntfs_free(rl); |
| 973 | return ERR_PTR(-EIO); |
| 974 | } |
| 975 | |
| 976 | /** |
| 977 | * ntfs_rl_vcn_to_lcn - convert a vcn into a lcn given a runlist |
| 978 | * @rl: runlist to use for conversion |
| 979 | * @vcn: vcn to convert |
| 980 | * |
| 981 | * Convert the virtual cluster number @vcn of an attribute into a logical |
| 982 | * cluster number (lcn) of a device using the runlist @rl to map vcns to their |
| 983 | * corresponding lcns. |
| 984 | * |
| 985 | * It is up to the caller to serialize access to the runlist @rl. |
| 986 | * |
Anton Altaparmakov | c0c1cc0 | 2005-03-07 21:43:38 +0000 | [diff] [blame] | 987 | * Since lcns must be >= 0, we use negative return codes with special meaning: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 988 | * |
Anton Altaparmakov | c0c1cc0 | 2005-03-07 21:43:38 +0000 | [diff] [blame] | 989 | * Return code Meaning / Description |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | * ================================================== |
Anton Altaparmakov | c0c1cc0 | 2005-03-07 21:43:38 +0000 | [diff] [blame] | 991 | * LCN_HOLE Hole / not allocated on disk. |
| 992 | * LCN_RL_NOT_MAPPED This is part of the runlist which has not been |
| 993 | * inserted into the runlist yet. |
| 994 | * LCN_ENOENT There is no such vcn in the attribute. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 995 | * |
| 996 | * Locking: - The caller must have locked the runlist (for reading or writing). |
Anton Altaparmakov | c0c1cc0 | 2005-03-07 21:43:38 +0000 | [diff] [blame] | 997 | * - This function does not touch the lock, nor does it modify the |
| 998 | * runlist. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | */ |
| 1000 | LCN ntfs_rl_vcn_to_lcn(const runlist_element *rl, const VCN vcn) |
| 1001 | { |
| 1002 | int i; |
| 1003 | |
| 1004 | BUG_ON(vcn < 0); |
| 1005 | /* |
| 1006 | * If rl is NULL, assume that we have found an unmapped runlist. The |
| 1007 | * caller can then attempt to map it and fail appropriately if |
| 1008 | * necessary. |
| 1009 | */ |
| 1010 | if (unlikely(!rl)) |
| 1011 | return LCN_RL_NOT_MAPPED; |
| 1012 | |
| 1013 | /* Catch out of lower bounds vcn. */ |
| 1014 | if (unlikely(vcn < rl[0].vcn)) |
| 1015 | return LCN_ENOENT; |
| 1016 | |
| 1017 | for (i = 0; likely(rl[i].length); i++) { |
| 1018 | if (unlikely(vcn < rl[i+1].vcn)) { |
| 1019 | if (likely(rl[i].lcn >= (LCN)0)) |
| 1020 | return rl[i].lcn + (vcn - rl[i].vcn); |
| 1021 | return rl[i].lcn; |
| 1022 | } |
| 1023 | } |
| 1024 | /* |
| 1025 | * The terminator element is setup to the correct value, i.e. one of |
| 1026 | * LCN_HOLE, LCN_RL_NOT_MAPPED, or LCN_ENOENT. |
| 1027 | */ |
| 1028 | if (likely(rl[i].lcn < (LCN)0)) |
| 1029 | return rl[i].lcn; |
| 1030 | /* Just in case... We could replace this with BUG() some day. */ |
| 1031 | return LCN_ENOENT; |
| 1032 | } |
| 1033 | |
Anton Altaparmakov | 53d59aa | 2005-03-17 10:51:33 +0000 | [diff] [blame] | 1034 | #ifdef NTFS_RW |
| 1035 | |
| 1036 | /** |
| 1037 | * ntfs_rl_find_vcn_nolock - find a vcn in a runlist |
| 1038 | * @rl: runlist to search |
| 1039 | * @vcn: vcn to find |
| 1040 | * |
| 1041 | * Find the virtual cluster number @vcn in the runlist @rl and return the |
| 1042 | * address of the runlist element containing the @vcn on success. |
| 1043 | * |
| 1044 | * Return NULL if @rl is NULL or @vcn is in an unmapped part/out of bounds of |
| 1045 | * the runlist. |
| 1046 | * |
| 1047 | * Locking: The runlist must be locked on entry. |
| 1048 | */ |
| 1049 | runlist_element *ntfs_rl_find_vcn_nolock(runlist_element *rl, const VCN vcn) |
| 1050 | { |
| 1051 | BUG_ON(vcn < 0); |
| 1052 | if (unlikely(!rl || vcn < rl[0].vcn)) |
| 1053 | return NULL; |
| 1054 | while (likely(rl->length)) { |
| 1055 | if (unlikely(vcn < rl[1].vcn)) { |
| 1056 | if (likely(rl->lcn >= LCN_HOLE)) |
| 1057 | return rl; |
| 1058 | return NULL; |
| 1059 | } |
| 1060 | rl++; |
| 1061 | } |
| 1062 | if (likely(rl->lcn == LCN_ENOENT)) |
| 1063 | return rl; |
| 1064 | return NULL; |
| 1065 | } |
| 1066 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1067 | /** |
| 1068 | * ntfs_get_nr_significant_bytes - get number of bytes needed to store a number |
| 1069 | * @n: number for which to get the number of bytes for |
| 1070 | * |
| 1071 | * Return the number of bytes required to store @n unambiguously as |
| 1072 | * a signed number. |
| 1073 | * |
| 1074 | * This is used in the context of the mapping pairs array to determine how |
| 1075 | * many bytes will be needed in the array to store a given logical cluster |
| 1076 | * number (lcn) or a specific run length. |
| 1077 | * |
| 1078 | * Return the number of bytes written. This function cannot fail. |
| 1079 | */ |
| 1080 | static inline int ntfs_get_nr_significant_bytes(const s64 n) |
| 1081 | { |
| 1082 | s64 l = n; |
| 1083 | int i; |
| 1084 | s8 j; |
| 1085 | |
| 1086 | i = 0; |
| 1087 | do { |
| 1088 | l >>= 8; |
| 1089 | i++; |
| 1090 | } while (l != 0 && l != -1); |
| 1091 | j = (n >> 8 * (i - 1)) & 0xff; |
| 1092 | /* If the sign bit is wrong, we need an extra byte. */ |
| 1093 | if ((n < 0 && j >= 0) || (n > 0 && j < 0)) |
| 1094 | i++; |
| 1095 | return i; |
| 1096 | } |
| 1097 | |
| 1098 | /** |
| 1099 | * ntfs_get_size_for_mapping_pairs - get bytes needed for mapping pairs array |
| 1100 | * @vol: ntfs volume (needed for the ntfs version) |
| 1101 | * @rl: locked runlist to determine the size of the mapping pairs of |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1102 | * @first_vcn: first vcn which to include in the mapping pairs array |
| 1103 | * @last_vcn: last vcn which to include in the mapping pairs array |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1104 | * |
| 1105 | * Walk the locked runlist @rl and calculate the size in bytes of the mapping |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1106 | * pairs array corresponding to the runlist @rl, starting at vcn @first_vcn and |
| 1107 | * finishing with vcn @last_vcn. |
| 1108 | * |
| 1109 | * A @last_vcn of -1 means end of runlist and in that case the size of the |
| 1110 | * mapping pairs array corresponding to the runlist starting at vcn @first_vcn |
| 1111 | * and finishing at the end of the runlist is determined. |
| 1112 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1113 | * This for example allows us to allocate a buffer of the right size when |
| 1114 | * building the mapping pairs array. |
| 1115 | * |
| 1116 | * If @rl is NULL, just return 1 (for the single terminator byte). |
| 1117 | * |
| 1118 | * Return the calculated size in bytes on success. On error, return -errno. |
| 1119 | * The following error codes are defined: |
| 1120 | * -EINVAL - Run list contains unmapped elements. Make sure to only pass |
| 1121 | * fully mapped runlists to this function. |
| 1122 | * -EIO - The runlist is corrupt. |
| 1123 | * |
| 1124 | * Locking: @rl must be locked on entry (either for reading or writing), it |
| 1125 | * remains locked throughout, and is left locked upon return. |
| 1126 | */ |
| 1127 | int ntfs_get_size_for_mapping_pairs(const ntfs_volume *vol, |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1128 | const runlist_element *rl, const VCN first_vcn, |
| 1129 | const VCN last_vcn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1130 | { |
| 1131 | LCN prev_lcn; |
| 1132 | int rls; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1133 | BOOL the_end = FALSE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1134 | |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1135 | BUG_ON(first_vcn < 0); |
| 1136 | BUG_ON(last_vcn < -1); |
| 1137 | BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1138 | if (!rl) { |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1139 | BUG_ON(first_vcn); |
| 1140 | BUG_ON(last_vcn > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1141 | return 1; |
| 1142 | } |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1143 | /* Skip to runlist element containing @first_vcn. */ |
| 1144 | while (rl->length && first_vcn >= rl[1].vcn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1145 | rl++; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1146 | if (unlikely((!rl->length && first_vcn > rl->vcn) || |
| 1147 | first_vcn < rl->vcn)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1148 | return -EINVAL; |
| 1149 | prev_lcn = 0; |
| 1150 | /* Always need the termining zero byte. */ |
| 1151 | rls = 1; |
| 1152 | /* Do the first partial run if present. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1153 | if (first_vcn > rl->vcn) { |
| 1154 | s64 delta, length = rl->length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | |
| 1156 | /* We know rl->length != 0 already. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1157 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1158 | goto err_out; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1159 | /* |
| 1160 | * If @stop_vcn is given and finishes inside this run, cap the |
| 1161 | * run length. |
| 1162 | */ |
| 1163 | if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { |
| 1164 | s64 s1 = last_vcn + 1; |
| 1165 | if (unlikely(rl[1].vcn > s1)) |
| 1166 | length = s1 - rl->vcn; |
| 1167 | the_end = TRUE; |
| 1168 | } |
| 1169 | delta = first_vcn - rl->vcn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1170 | /* Header byte + length. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1171 | rls += 1 + ntfs_get_nr_significant_bytes(length - delta); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1172 | /* |
| 1173 | * If the logical cluster number (lcn) denotes a hole and we |
| 1174 | * are on NTFS 3.0+, we don't store it at all, i.e. we need |
| 1175 | * zero space. On earlier NTFS versions we just store the lcn. |
| 1176 | * Note: this assumes that on NTFS 1.2-, holes are stored with |
| 1177 | * an lcn of -1 and not a delta_lcn of -1 (unless both are -1). |
| 1178 | */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1179 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1180 | prev_lcn = rl->lcn; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1181 | if (likely(rl->lcn >= 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1182 | prev_lcn += delta; |
| 1183 | /* Change in lcn. */ |
| 1184 | rls += ntfs_get_nr_significant_bytes(prev_lcn); |
| 1185 | } |
| 1186 | /* Go to next runlist element. */ |
| 1187 | rl++; |
| 1188 | } |
| 1189 | /* Do the full runs. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1190 | for (; rl->length && !the_end; rl++) { |
| 1191 | s64 length = rl->length; |
| 1192 | |
| 1193 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1194 | goto err_out; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1195 | /* |
| 1196 | * If @stop_vcn is given and finishes inside this run, cap the |
| 1197 | * run length. |
| 1198 | */ |
| 1199 | if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { |
| 1200 | s64 s1 = last_vcn + 1; |
| 1201 | if (unlikely(rl[1].vcn > s1)) |
| 1202 | length = s1 - rl->vcn; |
| 1203 | the_end = TRUE; |
| 1204 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1205 | /* Header byte + length. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1206 | rls += 1 + ntfs_get_nr_significant_bytes(length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1207 | /* |
| 1208 | * If the logical cluster number (lcn) denotes a hole and we |
| 1209 | * are on NTFS 3.0+, we don't store it at all, i.e. we need |
| 1210 | * zero space. On earlier NTFS versions we just store the lcn. |
| 1211 | * Note: this assumes that on NTFS 1.2-, holes are stored with |
| 1212 | * an lcn of -1 and not a delta_lcn of -1 (unless both are -1). |
| 1213 | */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1214 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1215 | /* Change in lcn. */ |
| 1216 | rls += ntfs_get_nr_significant_bytes(rl->lcn - |
| 1217 | prev_lcn); |
| 1218 | prev_lcn = rl->lcn; |
| 1219 | } |
| 1220 | } |
| 1221 | return rls; |
| 1222 | err_out: |
| 1223 | if (rl->lcn == LCN_RL_NOT_MAPPED) |
| 1224 | rls = -EINVAL; |
| 1225 | else |
| 1226 | rls = -EIO; |
| 1227 | return rls; |
| 1228 | } |
| 1229 | |
| 1230 | /** |
| 1231 | * ntfs_write_significant_bytes - write the significant bytes of a number |
| 1232 | * @dst: destination buffer to write to |
| 1233 | * @dst_max: pointer to last byte of destination buffer for bounds checking |
| 1234 | * @n: number whose significant bytes to write |
| 1235 | * |
| 1236 | * Store in @dst, the minimum bytes of the number @n which are required to |
| 1237 | * identify @n unambiguously as a signed number, taking care not to exceed |
| 1238 | * @dest_max, the maximum position within @dst to which we are allowed to |
| 1239 | * write. |
| 1240 | * |
| 1241 | * This is used when building the mapping pairs array of a runlist to compress |
| 1242 | * a given logical cluster number (lcn) or a specific run length to the minumum |
| 1243 | * size possible. |
| 1244 | * |
| 1245 | * Return the number of bytes written on success. On error, i.e. the |
| 1246 | * destination buffer @dst is too small, return -ENOSPC. |
| 1247 | */ |
| 1248 | static inline int ntfs_write_significant_bytes(s8 *dst, const s8 *dst_max, |
| 1249 | const s64 n) |
| 1250 | { |
| 1251 | s64 l = n; |
| 1252 | int i; |
| 1253 | s8 j; |
| 1254 | |
| 1255 | i = 0; |
| 1256 | do { |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1257 | if (unlikely(dst > dst_max)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1258 | goto err_out; |
| 1259 | *dst++ = l & 0xffll; |
| 1260 | l >>= 8; |
| 1261 | i++; |
| 1262 | } while (l != 0 && l != -1); |
| 1263 | j = (n >> 8 * (i - 1)) & 0xff; |
| 1264 | /* If the sign bit is wrong, we need an extra byte. */ |
| 1265 | if (n < 0 && j >= 0) { |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1266 | if (unlikely(dst > dst_max)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1267 | goto err_out; |
| 1268 | i++; |
| 1269 | *dst = (s8)-1; |
| 1270 | } else if (n > 0 && j < 0) { |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1271 | if (unlikely(dst > dst_max)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1272 | goto err_out; |
| 1273 | i++; |
| 1274 | *dst = (s8)0; |
| 1275 | } |
| 1276 | return i; |
| 1277 | err_out: |
| 1278 | return -ENOSPC; |
| 1279 | } |
| 1280 | |
| 1281 | /** |
| 1282 | * ntfs_mapping_pairs_build - build the mapping pairs array from a runlist |
| 1283 | * @vol: ntfs volume (needed for the ntfs version) |
| 1284 | * @dst: destination buffer to which to write the mapping pairs array |
| 1285 | * @dst_len: size of destination buffer @dst in bytes |
| 1286 | * @rl: locked runlist for which to build the mapping pairs array |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1287 | * @first_vcn: first vcn which to include in the mapping pairs array |
| 1288 | * @last_vcn: last vcn which to include in the mapping pairs array |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1289 | * @stop_vcn: first vcn outside destination buffer on success or -ENOSPC |
| 1290 | * |
| 1291 | * Create the mapping pairs array from the locked runlist @rl, starting at vcn |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1292 | * @first_vcn and finishing with vcn @last_vcn and save the array in @dst. |
| 1293 | * @dst_len is the size of @dst in bytes and it should be at least equal to the |
| 1294 | * value obtained by calling ntfs_get_size_for_mapping_pairs(). |
| 1295 | * |
| 1296 | * A @last_vcn of -1 means end of runlist and in that case the mapping pairs |
| 1297 | * array corresponding to the runlist starting at vcn @first_vcn and finishing |
| 1298 | * at the end of the runlist is created. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1299 | * |
| 1300 | * If @rl is NULL, just write a single terminator byte to @dst. |
| 1301 | * |
| 1302 | * On success or -ENOSPC error, if @stop_vcn is not NULL, *@stop_vcn is set to |
| 1303 | * the first vcn outside the destination buffer. Note that on error, @dst has |
| 1304 | * been filled with all the mapping pairs that will fit, thus it can be treated |
| 1305 | * as partial success, in that a new attribute extent needs to be created or |
| 1306 | * the next extent has to be used and the mapping pairs build has to be |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1307 | * continued with @first_vcn set to *@stop_vcn. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1308 | * |
| 1309 | * Return 0 on success and -errno on error. The following error codes are |
| 1310 | * defined: |
| 1311 | * -EINVAL - Run list contains unmapped elements. Make sure to only pass |
| 1312 | * fully mapped runlists to this function. |
| 1313 | * -EIO - The runlist is corrupt. |
| 1314 | * -ENOSPC - The destination buffer is too small. |
| 1315 | * |
| 1316 | * Locking: @rl must be locked on entry (either for reading or writing), it |
| 1317 | * remains locked throughout, and is left locked upon return. |
| 1318 | */ |
| 1319 | int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst, |
| 1320 | const int dst_len, const runlist_element *rl, |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1321 | const VCN first_vcn, const VCN last_vcn, VCN *const stop_vcn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1322 | { |
| 1323 | LCN prev_lcn; |
| 1324 | s8 *dst_max, *dst_next; |
| 1325 | int err = -ENOSPC; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1326 | BOOL the_end = FALSE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1327 | s8 len_len, lcn_len; |
| 1328 | |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1329 | BUG_ON(first_vcn < 0); |
| 1330 | BUG_ON(last_vcn < -1); |
| 1331 | BUG_ON(last_vcn >= 0 && first_vcn > last_vcn); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1332 | BUG_ON(dst_len < 1); |
| 1333 | if (!rl) { |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1334 | BUG_ON(first_vcn); |
| 1335 | BUG_ON(last_vcn > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1336 | if (stop_vcn) |
| 1337 | *stop_vcn = 0; |
| 1338 | /* Terminator byte. */ |
| 1339 | *dst = 0; |
| 1340 | return 0; |
| 1341 | } |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1342 | /* Skip to runlist element containing @first_vcn. */ |
| 1343 | while (rl->length && first_vcn >= rl[1].vcn) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1344 | rl++; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1345 | if (unlikely((!rl->length && first_vcn > rl->vcn) || |
| 1346 | first_vcn < rl->vcn)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1347 | return -EINVAL; |
| 1348 | /* |
| 1349 | * @dst_max is used for bounds checking in |
| 1350 | * ntfs_write_significant_bytes(). |
| 1351 | */ |
| 1352 | dst_max = dst + dst_len - 1; |
| 1353 | prev_lcn = 0; |
| 1354 | /* Do the first partial run if present. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1355 | if (first_vcn > rl->vcn) { |
| 1356 | s64 delta, length = rl->length; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1357 | |
| 1358 | /* We know rl->length != 0 already. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1359 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1360 | goto err_out; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1361 | /* |
| 1362 | * If @stop_vcn is given and finishes inside this run, cap the |
| 1363 | * run length. |
| 1364 | */ |
| 1365 | if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { |
| 1366 | s64 s1 = last_vcn + 1; |
| 1367 | if (unlikely(rl[1].vcn > s1)) |
| 1368 | length = s1 - rl->vcn; |
| 1369 | the_end = TRUE; |
| 1370 | } |
| 1371 | delta = first_vcn - rl->vcn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1372 | /* Write length. */ |
| 1373 | len_len = ntfs_write_significant_bytes(dst + 1, dst_max, |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1374 | length - delta); |
| 1375 | if (unlikely(len_len < 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1376 | goto size_err; |
| 1377 | /* |
| 1378 | * If the logical cluster number (lcn) denotes a hole and we |
| 1379 | * are on NTFS 3.0+, we don't store it at all, i.e. we need |
| 1380 | * zero space. On earlier NTFS versions we just write the lcn |
| 1381 | * change. FIXME: Do we need to write the lcn change or just |
| 1382 | * the lcn in that case? Not sure as I have never seen this |
| 1383 | * case on NT4. - We assume that we just need to write the lcn |
| 1384 | * change until someone tells us otherwise... (AIA) |
| 1385 | */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1386 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1387 | prev_lcn = rl->lcn; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1388 | if (likely(rl->lcn >= 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1389 | prev_lcn += delta; |
| 1390 | /* Write change in lcn. */ |
| 1391 | lcn_len = ntfs_write_significant_bytes(dst + 1 + |
| 1392 | len_len, dst_max, prev_lcn); |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1393 | if (unlikely(lcn_len < 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1394 | goto size_err; |
| 1395 | } else |
| 1396 | lcn_len = 0; |
| 1397 | dst_next = dst + len_len + lcn_len + 1; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1398 | if (unlikely(dst_next > dst_max)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1399 | goto size_err; |
| 1400 | /* Update header byte. */ |
| 1401 | *dst = lcn_len << 4 | len_len; |
| 1402 | /* Position at next mapping pairs array element. */ |
| 1403 | dst = dst_next; |
| 1404 | /* Go to next runlist element. */ |
| 1405 | rl++; |
| 1406 | } |
| 1407 | /* Do the full runs. */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1408 | for (; rl->length && !the_end; rl++) { |
| 1409 | s64 length = rl->length; |
| 1410 | |
| 1411 | if (unlikely(length < 0 || rl->lcn < LCN_HOLE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1412 | goto err_out; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1413 | /* |
| 1414 | * If @stop_vcn is given and finishes inside this run, cap the |
| 1415 | * run length. |
| 1416 | */ |
| 1417 | if (unlikely(last_vcn >= 0 && rl[1].vcn > last_vcn)) { |
| 1418 | s64 s1 = last_vcn + 1; |
| 1419 | if (unlikely(rl[1].vcn > s1)) |
| 1420 | length = s1 - rl->vcn; |
| 1421 | the_end = TRUE; |
| 1422 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1423 | /* Write length. */ |
| 1424 | len_len = ntfs_write_significant_bytes(dst + 1, dst_max, |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1425 | length); |
| 1426 | if (unlikely(len_len < 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1427 | goto size_err; |
| 1428 | /* |
| 1429 | * If the logical cluster number (lcn) denotes a hole and we |
| 1430 | * are on NTFS 3.0+, we don't store it at all, i.e. we need |
| 1431 | * zero space. On earlier NTFS versions we just write the lcn |
| 1432 | * change. FIXME: Do we need to write the lcn change or just |
| 1433 | * the lcn in that case? Not sure as I have never seen this |
| 1434 | * case on NT4. - We assume that we just need to write the lcn |
| 1435 | * change until someone tells us otherwise... (AIA) |
| 1436 | */ |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1437 | if (likely(rl->lcn >= 0 || vol->major_ver < 3)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1438 | /* Write change in lcn. */ |
| 1439 | lcn_len = ntfs_write_significant_bytes(dst + 1 + |
| 1440 | len_len, dst_max, rl->lcn - prev_lcn); |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1441 | if (unlikely(lcn_len < 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | goto size_err; |
| 1443 | prev_lcn = rl->lcn; |
| 1444 | } else |
| 1445 | lcn_len = 0; |
| 1446 | dst_next = dst + len_len + lcn_len + 1; |
Anton Altaparmakov | fa3be923 | 2005-06-25 17:15:36 +0100 | [diff] [blame] | 1447 | if (unlikely(dst_next > dst_max)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1448 | goto size_err; |
| 1449 | /* Update header byte. */ |
| 1450 | *dst = lcn_len << 4 | len_len; |
| 1451 | /* Position at next mapping pairs array element. */ |
| 1452 | dst = dst_next; |
| 1453 | } |
| 1454 | /* Success. */ |
| 1455 | err = 0; |
| 1456 | size_err: |
| 1457 | /* Set stop vcn. */ |
| 1458 | if (stop_vcn) |
| 1459 | *stop_vcn = rl->vcn; |
| 1460 | /* Add terminator byte. */ |
| 1461 | *dst = 0; |
| 1462 | return err; |
| 1463 | err_out: |
| 1464 | if (rl->lcn == LCN_RL_NOT_MAPPED) |
| 1465 | err = -EINVAL; |
| 1466 | else |
| 1467 | err = -EIO; |
| 1468 | return err; |
| 1469 | } |
| 1470 | |
| 1471 | /** |
| 1472 | * ntfs_rl_truncate_nolock - truncate a runlist starting at a specified vcn |
Anton Altaparmakov | 3ffc5a4 | 2005-09-08 20:23:06 +0100 | [diff] [blame] | 1473 | * @vol: ntfs volume (needed for error output) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1474 | * @runlist: runlist to truncate |
| 1475 | * @new_length: the new length of the runlist in VCNs |
| 1476 | * |
| 1477 | * Truncate the runlist described by @runlist as well as the memory buffer |
| 1478 | * holding the runlist elements to a length of @new_length VCNs. |
| 1479 | * |
| 1480 | * If @new_length lies within the runlist, the runlist elements with VCNs of |
Anton Altaparmakov | 3ffc5a4 | 2005-09-08 20:23:06 +0100 | [diff] [blame] | 1481 | * @new_length and above are discarded. As a special case if @new_length is |
| 1482 | * zero, the runlist is discarded and set to NULL. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1483 | * |
| 1484 | * If @new_length lies beyond the runlist, a sparse runlist element is added to |
| 1485 | * the end of the runlist @runlist or if the last runlist element is a sparse |
| 1486 | * one already, this is extended. |
| 1487 | * |
Anton Altaparmakov | 3ffc5a4 | 2005-09-08 20:23:06 +0100 | [diff] [blame] | 1488 | * Note, no checking is done for unmapped runlist elements. It is assumed that |
| 1489 | * the caller has mapped any elements that need to be mapped already. |
| 1490 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1491 | * Return 0 on success and -errno on error. |
| 1492 | * |
| 1493 | * Locking: The caller must hold @runlist->lock for writing. |
| 1494 | */ |
| 1495 | int ntfs_rl_truncate_nolock(const ntfs_volume *vol, runlist *const runlist, |
| 1496 | const s64 new_length) |
| 1497 | { |
| 1498 | runlist_element *rl; |
| 1499 | int old_size; |
| 1500 | |
| 1501 | ntfs_debug("Entering for new_length 0x%llx.", (long long)new_length); |
| 1502 | BUG_ON(!runlist); |
| 1503 | BUG_ON(new_length < 0); |
| 1504 | rl = runlist->rl; |
Anton Altaparmakov | 3ffc5a4 | 2005-09-08 20:23:06 +0100 | [diff] [blame] | 1505 | if (!new_length) { |
| 1506 | ntfs_debug("Freeing runlist."); |
| 1507 | runlist->rl = NULL; |
| 1508 | if (rl) |
| 1509 | ntfs_free(rl); |
| 1510 | return 0; |
| 1511 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1512 | if (unlikely(!rl)) { |
| 1513 | /* |
| 1514 | * Create a runlist consisting of a sparse runlist element of |
| 1515 | * length @new_length followed by a terminator runlist element. |
| 1516 | */ |
| 1517 | rl = ntfs_malloc_nofs(PAGE_SIZE); |
| 1518 | if (unlikely(!rl)) { |
| 1519 | ntfs_error(vol->sb, "Not enough memory to allocate " |
| 1520 | "runlist element buffer."); |
| 1521 | return -ENOMEM; |
| 1522 | } |
| 1523 | runlist->rl = rl; |
| 1524 | rl[1].length = rl->vcn = 0; |
| 1525 | rl->lcn = LCN_HOLE; |
| 1526 | rl[1].vcn = rl->length = new_length; |
| 1527 | rl[1].lcn = LCN_ENOENT; |
| 1528 | return 0; |
| 1529 | } |
| 1530 | BUG_ON(new_length < rl->vcn); |
| 1531 | /* Find @new_length in the runlist. */ |
| 1532 | while (likely(rl->length && new_length >= rl[1].vcn)) |
| 1533 | rl++; |
| 1534 | /* |
| 1535 | * If not at the end of the runlist we need to shrink it. |
| 1536 | * If at the end of the runlist we need to expand it. |
| 1537 | */ |
| 1538 | if (rl->length) { |
| 1539 | runlist_element *trl; |
| 1540 | BOOL is_end; |
| 1541 | |
| 1542 | ntfs_debug("Shrinking runlist."); |
| 1543 | /* Determine the runlist size. */ |
| 1544 | trl = rl + 1; |
| 1545 | while (likely(trl->length)) |
| 1546 | trl++; |
| 1547 | old_size = trl - runlist->rl + 1; |
| 1548 | /* Truncate the run. */ |
| 1549 | rl->length = new_length - rl->vcn; |
| 1550 | /* |
| 1551 | * If a run was partially truncated, make the following runlist |
| 1552 | * element a terminator. |
| 1553 | */ |
| 1554 | is_end = FALSE; |
| 1555 | if (rl->length) { |
| 1556 | rl++; |
| 1557 | if (!rl->length) |
| 1558 | is_end = TRUE; |
| 1559 | rl->vcn = new_length; |
| 1560 | rl->length = 0; |
| 1561 | } |
| 1562 | rl->lcn = LCN_ENOENT; |
| 1563 | /* Reallocate memory if necessary. */ |
| 1564 | if (!is_end) { |
| 1565 | int new_size = rl - runlist->rl + 1; |
| 1566 | rl = ntfs_rl_realloc(runlist->rl, old_size, new_size); |
| 1567 | if (IS_ERR(rl)) |
| 1568 | ntfs_warning(vol->sb, "Failed to shrink " |
| 1569 | "runlist buffer. This just " |
| 1570 | "wastes a bit of memory " |
| 1571 | "temporarily so we ignore it " |
| 1572 | "and return success."); |
| 1573 | else |
| 1574 | runlist->rl = rl; |
| 1575 | } |
| 1576 | } else if (likely(/* !rl->length && */ new_length > rl->vcn)) { |
| 1577 | ntfs_debug("Expanding runlist."); |
| 1578 | /* |
| 1579 | * If there is a previous runlist element and it is a sparse |
| 1580 | * one, extend it. Otherwise need to add a new, sparse runlist |
| 1581 | * element. |
| 1582 | */ |
| 1583 | if ((rl > runlist->rl) && ((rl - 1)->lcn == LCN_HOLE)) |
| 1584 | (rl - 1)->length = new_length - (rl - 1)->vcn; |
| 1585 | else { |
| 1586 | /* Determine the runlist size. */ |
| 1587 | old_size = rl - runlist->rl + 1; |
| 1588 | /* Reallocate memory if necessary. */ |
| 1589 | rl = ntfs_rl_realloc(runlist->rl, old_size, |
| 1590 | old_size + 1); |
| 1591 | if (IS_ERR(rl)) { |
| 1592 | ntfs_error(vol->sb, "Failed to expand runlist " |
| 1593 | "buffer, aborting."); |
| 1594 | return PTR_ERR(rl); |
| 1595 | } |
| 1596 | runlist->rl = rl; |
| 1597 | /* |
| 1598 | * Set @rl to the same runlist element in the new |
| 1599 | * runlist as before in the old runlist. |
| 1600 | */ |
| 1601 | rl += old_size - 1; |
| 1602 | /* Add a new, sparse runlist element. */ |
| 1603 | rl->lcn = LCN_HOLE; |
| 1604 | rl->length = new_length - rl->vcn; |
| 1605 | /* Add a new terminator runlist element. */ |
| 1606 | rl++; |
| 1607 | rl->length = 0; |
| 1608 | } |
| 1609 | rl->vcn = new_length; |
| 1610 | rl->lcn = LCN_ENOENT; |
| 1611 | } else /* if (unlikely(!rl->length && new_length == rl->vcn)) */ { |
| 1612 | /* Runlist already has same size as requested. */ |
| 1613 | rl->lcn = LCN_ENOENT; |
| 1614 | } |
| 1615 | ntfs_debug("Done."); |
| 1616 | return 0; |
| 1617 | } |
Anton Altaparmakov | 53d59aa | 2005-03-17 10:51:33 +0000 | [diff] [blame] | 1618 | |
Anton Altaparmakov | 6e48321 | 2005-09-08 20:26:34 +0100 | [diff] [blame] | 1619 | /** |
| 1620 | * ntfs_rl_punch_nolock - punch a hole into a runlist |
| 1621 | * @vol: ntfs volume (needed for error output) |
| 1622 | * @runlist: runlist to punch a hole into |
| 1623 | * @start: starting VCN of the hole to be created |
| 1624 | * @length: size of the hole to be created in units of clusters |
| 1625 | * |
| 1626 | * Punch a hole into the runlist @runlist starting at VCN @start and of size |
| 1627 | * @length clusters. |
| 1628 | * |
| 1629 | * Return 0 on success and -errno on error, in which case @runlist has not been |
| 1630 | * modified. |
| 1631 | * |
| 1632 | * If @start and/or @start + @length are outside the runlist return error code |
| 1633 | * -ENOENT. |
| 1634 | * |
| 1635 | * If the runlist contains unmapped or error elements between @start and @start |
| 1636 | * + @length return error code -EINVAL. |
| 1637 | * |
| 1638 | * Locking: The caller must hold @runlist->lock for writing. |
| 1639 | */ |
| 1640 | int ntfs_rl_punch_nolock(const ntfs_volume *vol, runlist *const runlist, |
| 1641 | const VCN start, const s64 length) |
| 1642 | { |
| 1643 | const VCN end = start + length; |
| 1644 | s64 delta; |
| 1645 | runlist_element *rl, *rl_end, *rl_real_end, *trl; |
| 1646 | int old_size; |
| 1647 | BOOL lcn_fixup = FALSE; |
| 1648 | |
| 1649 | ntfs_debug("Entering for start 0x%llx, length 0x%llx.", |
| 1650 | (long long)start, (long long)length); |
| 1651 | BUG_ON(!runlist); |
| 1652 | BUG_ON(start < 0); |
| 1653 | BUG_ON(length < 0); |
| 1654 | BUG_ON(end < 0); |
| 1655 | rl = runlist->rl; |
| 1656 | if (unlikely(!rl)) { |
| 1657 | if (likely(!start && !length)) |
| 1658 | return 0; |
| 1659 | return -ENOENT; |
| 1660 | } |
| 1661 | /* Find @start in the runlist. */ |
| 1662 | while (likely(rl->length && start >= rl[1].vcn)) |
| 1663 | rl++; |
| 1664 | rl_end = rl; |
| 1665 | /* Find @end in the runlist. */ |
| 1666 | while (likely(rl_end->length && end >= rl_end[1].vcn)) { |
| 1667 | /* Verify there are no unmapped or error elements. */ |
| 1668 | if (unlikely(rl_end->lcn < LCN_HOLE)) |
| 1669 | return -EINVAL; |
| 1670 | rl_end++; |
| 1671 | } |
| 1672 | /* Check the last element. */ |
| 1673 | if (unlikely(rl_end->length && rl_end->lcn < LCN_HOLE)) |
| 1674 | return -EINVAL; |
| 1675 | /* This covers @start being out of bounds, too. */ |
| 1676 | if (!rl_end->length && end > rl_end->vcn) |
| 1677 | return -ENOENT; |
| 1678 | if (!length) |
| 1679 | return 0; |
| 1680 | if (!rl->length) |
| 1681 | return -ENOENT; |
| 1682 | rl_real_end = rl_end; |
| 1683 | /* Determine the runlist size. */ |
| 1684 | while (likely(rl_real_end->length)) |
| 1685 | rl_real_end++; |
| 1686 | old_size = rl_real_end - runlist->rl + 1; |
| 1687 | /* If @start is in a hole simply extend the hole. */ |
| 1688 | if (rl->lcn == LCN_HOLE) { |
| 1689 | /* |
| 1690 | * If both @start and @end are in the same sparse run, we are |
| 1691 | * done. |
| 1692 | */ |
| 1693 | if (end <= rl[1].vcn) { |
| 1694 | ntfs_debug("Done (requested hole is already sparse)."); |
| 1695 | return 0; |
| 1696 | } |
| 1697 | extend_hole: |
| 1698 | /* Extend the hole. */ |
| 1699 | rl->length = end - rl->vcn; |
| 1700 | /* If @end is in a hole, merge it with the current one. */ |
| 1701 | if (rl_end->lcn == LCN_HOLE) { |
| 1702 | rl_end++; |
| 1703 | rl->length = rl_end->vcn - rl->vcn; |
| 1704 | } |
| 1705 | /* We have done the hole. Now deal with the remaining tail. */ |
| 1706 | rl++; |
| 1707 | /* Cut out all runlist elements up to @end. */ |
| 1708 | if (rl < rl_end) |
| 1709 | memmove(rl, rl_end, (rl_real_end - rl_end + 1) * |
| 1710 | sizeof(*rl)); |
| 1711 | /* Adjust the beginning of the tail if necessary. */ |
| 1712 | if (end > rl->vcn) { |
| 1713 | s64 delta = end - rl->vcn; |
| 1714 | rl->vcn = end; |
| 1715 | rl->length -= delta; |
| 1716 | /* Only adjust the lcn if it is real. */ |
| 1717 | if (rl->lcn >= 0) |
| 1718 | rl->lcn += delta; |
| 1719 | } |
| 1720 | shrink_allocation: |
| 1721 | /* Reallocate memory if the allocation changed. */ |
| 1722 | if (rl < rl_end) { |
| 1723 | rl = ntfs_rl_realloc(runlist->rl, old_size, |
| 1724 | old_size - (rl_end - rl)); |
| 1725 | if (IS_ERR(rl)) |
| 1726 | ntfs_warning(vol->sb, "Failed to shrink " |
| 1727 | "runlist buffer. This just " |
| 1728 | "wastes a bit of memory " |
| 1729 | "temporarily so we ignore it " |
| 1730 | "and return success."); |
| 1731 | else |
| 1732 | runlist->rl = rl; |
| 1733 | } |
| 1734 | ntfs_debug("Done (extend hole)."); |
| 1735 | return 0; |
| 1736 | } |
| 1737 | /* |
| 1738 | * If @start is at the beginning of a run things are easier as there is |
| 1739 | * no need to split the first run. |
| 1740 | */ |
| 1741 | if (start == rl->vcn) { |
| 1742 | /* |
| 1743 | * @start is at the beginning of a run. |
| 1744 | * |
| 1745 | * If the previous run is sparse, extend its hole. |
| 1746 | * |
| 1747 | * If @end is not in the same run, switch the run to be sparse |
| 1748 | * and extend the newly created hole. |
| 1749 | * |
| 1750 | * Thus both of these cases reduce the problem to the above |
| 1751 | * case of "@start is in a hole". |
| 1752 | */ |
| 1753 | if (rl > runlist->rl && (rl - 1)->lcn == LCN_HOLE) { |
| 1754 | rl--; |
| 1755 | goto extend_hole; |
| 1756 | } |
| 1757 | if (end >= rl[1].vcn) { |
| 1758 | rl->lcn = LCN_HOLE; |
| 1759 | goto extend_hole; |
| 1760 | } |
| 1761 | /* |
| 1762 | * The final case is when @end is in the same run as @start. |
| 1763 | * For this need to split the run into two. One run for the |
| 1764 | * sparse region between the beginning of the old run, i.e. |
| 1765 | * @start, and @end and one for the remaining non-sparse |
| 1766 | * region, i.e. between @end and the end of the old run. |
| 1767 | */ |
| 1768 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); |
| 1769 | if (IS_ERR(trl)) |
| 1770 | goto enomem_out; |
| 1771 | old_size++; |
| 1772 | if (runlist->rl != trl) { |
| 1773 | rl = trl + (rl - runlist->rl); |
| 1774 | rl_end = trl + (rl_end - runlist->rl); |
| 1775 | rl_real_end = trl + (rl_real_end - runlist->rl); |
| 1776 | runlist->rl = trl; |
| 1777 | } |
| 1778 | split_end: |
| 1779 | /* Shift all the runs up by one. */ |
| 1780 | memmove(rl + 1, rl, (rl_real_end - rl + 1) * sizeof(*rl)); |
| 1781 | /* Finally, setup the two split runs. */ |
| 1782 | rl->lcn = LCN_HOLE; |
| 1783 | rl->length = length; |
| 1784 | rl++; |
| 1785 | rl->vcn += length; |
| 1786 | /* Only adjust the lcn if it is real. */ |
| 1787 | if (rl->lcn >= 0 || lcn_fixup) |
| 1788 | rl->lcn += length; |
| 1789 | rl->length -= length; |
| 1790 | ntfs_debug("Done (split one)."); |
| 1791 | return 0; |
| 1792 | } |
| 1793 | /* |
| 1794 | * @start is neither in a hole nor at the beginning of a run. |
| 1795 | * |
| 1796 | * If @end is in a hole, things are easier as simply truncating the run |
| 1797 | * @start is in to end at @start - 1, deleting all runs after that up |
| 1798 | * to @end, and finally extending the beginning of the run @end is in |
| 1799 | * to be @start is all that is needed. |
| 1800 | */ |
| 1801 | if (rl_end->lcn == LCN_HOLE) { |
| 1802 | /* Truncate the run containing @start. */ |
| 1803 | rl->length = start - rl->vcn; |
| 1804 | rl++; |
| 1805 | /* Cut out all runlist elements up to @end. */ |
| 1806 | if (rl < rl_end) |
| 1807 | memmove(rl, rl_end, (rl_real_end - rl_end + 1) * |
| 1808 | sizeof(*rl)); |
| 1809 | /* Extend the beginning of the run @end is in to be @start. */ |
| 1810 | rl->vcn = start; |
| 1811 | rl->length = rl[1].vcn - start; |
| 1812 | goto shrink_allocation; |
| 1813 | } |
| 1814 | /* |
| 1815 | * If @end is not in a hole there are still two cases to distinguish. |
| 1816 | * Either @end is or is not in the same run as @start. |
| 1817 | * |
| 1818 | * The second case is easier as it can be reduced to an already solved |
| 1819 | * problem by truncating the run @start is in to end at @start - 1. |
| 1820 | * Then, if @end is in the next run need to split the run into a sparse |
| 1821 | * run followed by a non-sparse run (already covered above) and if @end |
| 1822 | * is not in the next run switching it to be sparse, again reduces the |
| 1823 | * problem to the already covered case of "@start is in a hole". |
| 1824 | */ |
| 1825 | if (end >= rl[1].vcn) { |
| 1826 | /* |
| 1827 | * If @end is not in the next run, reduce the problem to the |
| 1828 | * case of "@start is in a hole". |
| 1829 | */ |
| 1830 | if (rl[1].length && end >= rl[2].vcn) { |
| 1831 | /* Truncate the run containing @start. */ |
| 1832 | rl->length = start - rl->vcn; |
| 1833 | rl++; |
| 1834 | rl->vcn = start; |
| 1835 | rl->lcn = LCN_HOLE; |
| 1836 | goto extend_hole; |
| 1837 | } |
| 1838 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 1); |
| 1839 | if (IS_ERR(trl)) |
| 1840 | goto enomem_out; |
| 1841 | old_size++; |
| 1842 | if (runlist->rl != trl) { |
| 1843 | rl = trl + (rl - runlist->rl); |
| 1844 | rl_end = trl + (rl_end - runlist->rl); |
| 1845 | rl_real_end = trl + (rl_real_end - runlist->rl); |
| 1846 | runlist->rl = trl; |
| 1847 | } |
| 1848 | /* Truncate the run containing @start. */ |
| 1849 | rl->length = start - rl->vcn; |
| 1850 | rl++; |
| 1851 | /* |
| 1852 | * @end is in the next run, reduce the problem to the case |
| 1853 | * where "@start is at the beginning of a run and @end is in |
| 1854 | * the same run as @start". |
| 1855 | */ |
| 1856 | delta = rl->vcn - start; |
| 1857 | rl->vcn = start; |
| 1858 | if (rl->lcn >= 0) { |
| 1859 | rl->lcn -= delta; |
| 1860 | /* Need this in case the lcn just became negative. */ |
| 1861 | lcn_fixup = TRUE; |
| 1862 | } |
| 1863 | rl->length += delta; |
| 1864 | goto split_end; |
| 1865 | } |
| 1866 | /* |
| 1867 | * The first case from above, i.e. @end is in the same run as @start. |
| 1868 | * We need to split the run into three. One run for the non-sparse |
| 1869 | * region between the beginning of the old run and @start, one for the |
| 1870 | * sparse region between @start and @end, and one for the remaining |
| 1871 | * non-sparse region, i.e. between @end and the end of the old run. |
| 1872 | */ |
| 1873 | trl = ntfs_rl_realloc(runlist->rl, old_size, old_size + 2); |
| 1874 | if (IS_ERR(trl)) |
| 1875 | goto enomem_out; |
| 1876 | old_size += 2; |
| 1877 | if (runlist->rl != trl) { |
| 1878 | rl = trl + (rl - runlist->rl); |
| 1879 | rl_end = trl + (rl_end - runlist->rl); |
| 1880 | rl_real_end = trl + (rl_real_end - runlist->rl); |
| 1881 | runlist->rl = trl; |
| 1882 | } |
| 1883 | /* Shift all the runs up by two. */ |
| 1884 | memmove(rl + 2, rl, (rl_real_end - rl + 1) * sizeof(*rl)); |
| 1885 | /* Finally, setup the three split runs. */ |
| 1886 | rl->length = start - rl->vcn; |
| 1887 | rl++; |
| 1888 | rl->vcn = start; |
| 1889 | rl->lcn = LCN_HOLE; |
| 1890 | rl->length = length; |
| 1891 | rl++; |
| 1892 | delta = end - rl->vcn; |
| 1893 | rl->vcn = end; |
| 1894 | rl->lcn += delta; |
| 1895 | rl->length -= delta; |
| 1896 | ntfs_debug("Done (split both)."); |
| 1897 | return 0; |
| 1898 | enomem_out: |
| 1899 | ntfs_error(vol->sb, "Not enough memory to extend runlist buffer."); |
| 1900 | return -ENOMEM; |
| 1901 | } |
| 1902 | |
Anton Altaparmakov | 53d59aa | 2005-03-17 10:51:33 +0000 | [diff] [blame] | 1903 | #endif /* NTFS_RW */ |