Theodore Ts'o | 69365c6 | 2009-08-22 13:27:40 -0400 | [diff] [blame] | 1 | /* |
| 2 | * blkmap64_ba.c --- Simple bitarray implementation for bitmaps |
| 3 | * |
| 4 | * Copyright (C) 2008 Theodore Ts'o. |
| 5 | * |
| 6 | * %Begin-Header% |
| 7 | * This file may be redistributed under the terms of the GNU Public |
| 8 | * License. |
| 9 | * %End-Header% |
| 10 | */ |
| 11 | |
Theodore Ts'o | d1154eb | 2011-09-18 17:34:37 -0400 | [diff] [blame] | 12 | #include "config.h" |
Theodore Ts'o | 69365c6 | 2009-08-22 13:27:40 -0400 | [diff] [blame] | 13 | #include <stdio.h> |
| 14 | #include <string.h> |
| 15 | #if HAVE_UNISTD_H |
| 16 | #include <unistd.h> |
| 17 | #endif |
| 18 | #include <fcntl.h> |
| 19 | #include <time.h> |
| 20 | #if HAVE_SYS_STAT_H |
| 21 | #include <sys/stat.h> |
| 22 | #endif |
| 23 | #if HAVE_SYS_TYPES_H |
| 24 | #include <sys/types.h> |
| 25 | #endif |
| 26 | |
| 27 | #include "ext2_fs.h" |
| 28 | #include "ext2fsP.h" |
| 29 | #include "bmap64.h" |
| 30 | |
| 31 | /* |
| 32 | * Private data for bit array implementation of bitmap ops. |
| 33 | * Currently, this is just a pointer to our big flat hunk of memory, |
| 34 | * exactly equivalent to the old-skool char * bitmap member. |
| 35 | */ |
| 36 | |
| 37 | struct ext2fs_ba_private_struct { |
| 38 | char *bitarray; |
| 39 | }; |
| 40 | |
| 41 | typedef struct ext2fs_ba_private_struct *ext2fs_ba_private; |
| 42 | |
| 43 | static errcode_t ba_alloc_private_data (ext2fs_generic_bitmap bitmap) |
| 44 | { |
| 45 | ext2fs_ba_private bp; |
| 46 | errcode_t retval; |
| 47 | size_t size; |
| 48 | |
| 49 | /* |
| 50 | * Since we only have the one pointer, we could just shove our |
| 51 | * private data in the void *private field itself, but then |
| 52 | * we'd have to do a fair bit of rewriting if we ever added a |
| 53 | * field. I'm agnostic. |
| 54 | */ |
| 55 | retval = ext2fs_get_mem(sizeof (ext2fs_ba_private), &bp); |
| 56 | if (retval) |
| 57 | return retval; |
| 58 | |
| 59 | size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1); |
| 60 | |
| 61 | retval = ext2fs_get_mem(size, &bp->bitarray); |
| 62 | if (retval) { |
| 63 | ext2fs_free_mem(&bp); |
| 64 | bp = 0; |
| 65 | return retval; |
| 66 | } |
| 67 | bitmap->private = (void *) bp; |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | static errcode_t ba_new_bmap(ext2_filsys fs EXT2FS_ATTR((unused)), |
| 72 | ext2fs_generic_bitmap bitmap) |
| 73 | { |
| 74 | ext2fs_ba_private bp; |
| 75 | errcode_t retval; |
| 76 | size_t size; |
| 77 | |
| 78 | retval = ba_alloc_private_data (bitmap); |
| 79 | if (retval) |
| 80 | return retval; |
| 81 | |
| 82 | bp = (ext2fs_ba_private) bitmap->private; |
| 83 | size = (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1); |
| 84 | memset(bp->bitarray, 0, size); |
| 85 | |
| 86 | return 0; |
| 87 | } |
| 88 | |
| 89 | static void ba_free_bmap(ext2fs_generic_bitmap bitmap) |
| 90 | { |
| 91 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 92 | |
| 93 | if (!bp) |
| 94 | return; |
| 95 | |
| 96 | if (bp->bitarray) { |
| 97 | ext2fs_free_mem (&bp->bitarray); |
| 98 | bp->bitarray = 0; |
| 99 | } |
| 100 | ext2fs_free_mem (&bp); |
| 101 | bp = 0; |
| 102 | } |
| 103 | |
| 104 | static errcode_t ba_copy_bmap(ext2fs_generic_bitmap src, |
| 105 | ext2fs_generic_bitmap dest) |
| 106 | { |
| 107 | ext2fs_ba_private src_bp = (ext2fs_ba_private) src->private; |
| 108 | ext2fs_ba_private dest_bp; |
| 109 | errcode_t retval; |
| 110 | size_t size; |
| 111 | |
| 112 | retval = ba_alloc_private_data (dest); |
| 113 | if (retval) |
| 114 | return retval; |
| 115 | |
| 116 | dest_bp = (ext2fs_ba_private) dest->private; |
| 117 | |
| 118 | size = (size_t) (((src->real_end - src->start) / 8) + 1); |
| 119 | memcpy (dest_bp->bitarray, src_bp->bitarray, size); |
| 120 | |
| 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static errcode_t ba_resize_bmap(ext2fs_generic_bitmap bmap, |
| 125 | __u64 new_end, __u64 new_real_end) |
| 126 | { |
| 127 | ext2fs_ba_private bp = (ext2fs_ba_private) bmap->private; |
| 128 | errcode_t retval; |
| 129 | size_t size, new_size; |
| 130 | __u64 bitno; |
| 131 | |
| 132 | /* |
| 133 | * If we're expanding the bitmap, make sure all of the new |
| 134 | * parts of the bitmap are zero. |
| 135 | */ |
| 136 | if (new_end > bmap->end) { |
| 137 | bitno = bmap->real_end; |
| 138 | if (bitno > new_end) |
| 139 | bitno = new_end; |
| 140 | for (; bitno > bmap->end; bitno--) |
| 141 | ext2fs_clear_bit64(bitno - bmap->start, bp->bitarray); |
| 142 | } |
| 143 | if (new_real_end == bmap->real_end) { |
| 144 | bmap->end = new_end; |
| 145 | return 0; |
| 146 | } |
| 147 | |
| 148 | size = ((bmap->real_end - bmap->start) / 8) + 1; |
| 149 | new_size = ((new_real_end - bmap->start) / 8) + 1; |
| 150 | |
| 151 | if (size != new_size) { |
| 152 | retval = ext2fs_resize_mem(size, new_size, &bp->bitarray); |
| 153 | if (retval) |
| 154 | return retval; |
| 155 | } |
| 156 | if (new_size > size) |
| 157 | memset(bp->bitarray + size, 0, new_size - size); |
| 158 | |
| 159 | bmap->end = new_end; |
| 160 | bmap->real_end = new_real_end; |
| 161 | return 0; |
| 162 | |
| 163 | } |
| 164 | |
| 165 | static int ba_mark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg) |
| 166 | { |
| 167 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 168 | blk64_t bitno = (blk64_t) arg; |
| 169 | |
| 170 | return ext2fs_set_bit64(bitno - bitmap->start, bp->bitarray); |
| 171 | } |
| 172 | |
| 173 | static int ba_unmark_bmap(ext2fs_generic_bitmap bitmap, __u64 arg) |
| 174 | { |
| 175 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 176 | blk64_t bitno = (blk64_t) arg; |
| 177 | |
| 178 | return ext2fs_clear_bit64(bitno - bitmap->start, bp->bitarray); |
| 179 | } |
| 180 | |
| 181 | static int ba_test_bmap(ext2fs_generic_bitmap bitmap, __u64 arg) |
| 182 | { |
| 183 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 184 | blk64_t bitno = (blk64_t) arg; |
| 185 | |
| 186 | return ext2fs_test_bit64(bitno - bitmap->start, bp->bitarray); |
| 187 | } |
| 188 | |
| 189 | static void ba_mark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg, |
| 190 | unsigned int num) |
| 191 | { |
| 192 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 193 | blk64_t bitno = (blk64_t) arg; |
| 194 | unsigned int i; |
| 195 | |
| 196 | for (i = 0; i < num; i++) |
| 197 | ext2fs_fast_set_bit64(bitno + i - bitmap->start, bp->bitarray); |
| 198 | } |
| 199 | |
| 200 | static void ba_unmark_bmap_extent(ext2fs_generic_bitmap bitmap, __u64 arg, |
| 201 | unsigned int num) |
| 202 | { |
| 203 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 204 | blk64_t bitno = (blk64_t) arg; |
| 205 | unsigned int i; |
| 206 | |
| 207 | for (i = 0; i < num; i++) |
| 208 | ext2fs_fast_clear_bit64(bitno + i - bitmap->start, bp->bitarray); |
| 209 | } |
| 210 | |
| 211 | static int ba_test_clear_bmap_extent(ext2fs_generic_bitmap bitmap, |
| 212 | __u64 start, unsigned int len) |
| 213 | { |
| 214 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 215 | __u64 start_byte, len_byte = len >> 3; |
| 216 | unsigned int start_bit, len_bit = len % 8; |
| 217 | unsigned int first_bit = 0; |
| 218 | unsigned int last_bit = 0; |
| 219 | int mark_count = 0; |
| 220 | int mark_bit = 0; |
| 221 | int i; |
| 222 | const char *ADDR; |
| 223 | |
| 224 | ADDR = bp->bitarray; |
| 225 | start -= bitmap->start; |
| 226 | start_byte = start >> 3; |
| 227 | start_bit = start % 8; |
| 228 | |
| 229 | if (start_bit != 0) { |
| 230 | /* |
| 231 | * The compared start block number or start inode number |
| 232 | * is not the first bit in a byte. |
| 233 | */ |
| 234 | mark_count = 8 - start_bit; |
| 235 | if (len < 8 - start_bit) { |
| 236 | mark_count = (int)len; |
| 237 | mark_bit = len + start_bit - 1; |
| 238 | } else |
| 239 | mark_bit = 7; |
| 240 | |
| 241 | for (i = mark_count; i > 0; i--, mark_bit--) |
| 242 | first_bit |= 1 << mark_bit; |
| 243 | |
| 244 | /* |
| 245 | * Compare blocks or inodes in the first byte. |
| 246 | * If there is any marked bit, this function returns 0. |
| 247 | */ |
| 248 | if (first_bit & ADDR[start_byte]) |
| 249 | return 0; |
| 250 | else if (len <= 8 - start_bit) |
| 251 | return 1; |
| 252 | |
| 253 | start_byte++; |
| 254 | len_bit = (len - mark_count) % 8; |
| 255 | len_byte = (len - mark_count) >> 3; |
| 256 | } |
| 257 | |
| 258 | /* |
| 259 | * The compared start block number or start inode number is |
| 260 | * the first bit in a byte. |
| 261 | */ |
| 262 | if (len_bit != 0) { |
| 263 | /* |
| 264 | * The compared end block number or end inode number is |
| 265 | * not the last bit in a byte. |
| 266 | */ |
| 267 | for (mark_bit = len_bit - 1; mark_bit >= 0; mark_bit--) |
| 268 | last_bit |= 1 << mark_bit; |
| 269 | |
| 270 | /* |
| 271 | * Compare blocks or inodes in the last byte. |
| 272 | * If there is any marked bit, this function returns 0. |
| 273 | */ |
| 274 | if (last_bit & ADDR[start_byte + len_byte]) |
| 275 | return 0; |
| 276 | else if (len_byte == 0) |
| 277 | return 1; |
| 278 | } |
| 279 | |
| 280 | /* Check whether all bytes are 0 */ |
| 281 | return ext2fs_mem_is_zero(ADDR + start_byte, len_byte); |
| 282 | } |
| 283 | |
| 284 | |
| 285 | static errcode_t ba_set_bmap_range(ext2fs_generic_bitmap bitmap, |
| 286 | __u64 start, size_t num, void *in) |
| 287 | { |
| 288 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 289 | |
| 290 | memcpy (bp->bitarray + (start >> 3), in, (num + 7) >> 3); |
| 291 | |
| 292 | return 0; |
| 293 | } |
| 294 | |
| 295 | static errcode_t ba_get_bmap_range(ext2fs_generic_bitmap bitmap, |
| 296 | __u64 start, size_t num, void *out) |
| 297 | { |
| 298 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 299 | |
| 300 | memcpy (out, bp->bitarray + (start >> 3), (num + 7) >> 3); |
| 301 | |
| 302 | return 0; |
| 303 | } |
| 304 | |
| 305 | static void ba_clear_bmap(ext2fs_generic_bitmap bitmap) |
| 306 | { |
| 307 | ext2fs_ba_private bp = (ext2fs_ba_private) bitmap->private; |
| 308 | |
| 309 | memset(bp->bitarray, 0, |
| 310 | (size_t) (((bitmap->real_end - bitmap->start) / 8) + 1)); |
| 311 | } |
| 312 | |
Lukas Czerner | 9288e3b | 2011-12-16 17:31:07 -0500 | [diff] [blame] | 313 | static void ba_print_stats(ext2fs_generic_bitmap bitmap) |
| 314 | { |
| 315 | fprintf(stderr, "%16llu Bytes used by bitarray\n", |
| 316 | ((bitmap->real_end - bitmap->start) >> 3) + 1 + |
| 317 | sizeof(struct ext2fs_ba_private_struct)); |
| 318 | } |
| 319 | |
Sami Liedes | 11f359f | 2012-03-10 23:38:40 +0200 | [diff] [blame] | 320 | /* Find the first zero bit between start and end, inclusive. */ |
| 321 | static errcode_t ba_find_first_zero(ext2fs_generic_bitmap bitmap, |
| 322 | __u64 start, __u64 end, __u64 *out) |
| 323 | { |
| 324 | ext2fs_ba_private bp = (ext2fs_ba_private)bitmap->private; |
| 325 | unsigned long bitpos = start - bitmap->start; |
| 326 | unsigned long count = end - start + 1; |
| 327 | int byte_found = 0; /* whether a != 0xff byte has been found */ |
| 328 | const unsigned char *pos; |
| 329 | unsigned long max_loop_count, i; |
| 330 | |
| 331 | if (start < bitmap->start || end > bitmap->end || start > end) |
| 332 | return EINVAL; |
| 333 | |
| 334 | if (bitmap->cluster_bits) |
| 335 | return EINVAL; |
| 336 | |
| 337 | /* scan bits until we hit a byte boundary */ |
| 338 | while ((bitpos & 0x7) != 0 && count > 0) { |
| 339 | if (!ext2fs_test_bit64(bitpos, bp->bitarray)) { |
| 340 | *out = bitpos + bitmap->start; |
| 341 | return 0; |
| 342 | } |
| 343 | bitpos++; |
| 344 | count--; |
| 345 | } |
| 346 | |
| 347 | if (!count) |
| 348 | return ENOENT; |
| 349 | |
| 350 | pos = ((unsigned char *)bp->bitarray) + (bitpos >> 3); |
| 351 | /* scan bytes until 8-byte (64-bit) aligned */ |
| 352 | while (count >= 8 && (((unsigned long)pos) & 0x07)) { |
| 353 | if (*pos != 0xff) { |
| 354 | byte_found = 1; |
| 355 | break; |
| 356 | } |
| 357 | pos++; |
| 358 | count -= 8; |
| 359 | bitpos += 8; |
| 360 | } |
| 361 | |
| 362 | if (!byte_found) { |
| 363 | max_loop_count = count >> 6; /* 8-byte blocks */ |
| 364 | i = max_loop_count; |
| 365 | while (i) { |
| 366 | if (*((const __u64 *)pos) != ((__u64)-1)) |
| 367 | break; |
| 368 | pos += 8; |
| 369 | i--; |
| 370 | } |
| 371 | count -= 64 * (max_loop_count - i); |
| 372 | bitpos += 64 * (max_loop_count - i); |
| 373 | |
| 374 | max_loop_count = count >> 3; |
| 375 | i = max_loop_count; |
| 376 | while (i) { |
| 377 | if (*pos != 0xff) { |
| 378 | byte_found = 1; |
| 379 | break; |
| 380 | } |
| 381 | pos++; |
| 382 | i--; |
| 383 | } |
| 384 | count -= 8 * (max_loop_count - i); |
| 385 | bitpos += 8 * (max_loop_count - i); |
| 386 | } |
| 387 | |
| 388 | /* Here either count < 8 or byte_found == 1. */ |
| 389 | while (count-- > 0) { |
| 390 | if (!ext2fs_test_bit64(bitpos, bp->bitarray)) { |
| 391 | *out = bitpos + bitmap->start; |
| 392 | return 0; |
| 393 | } |
| 394 | bitpos++; |
| 395 | } |
| 396 | |
| 397 | return ENOENT; |
| 398 | } |
| 399 | |
Theodore Ts'o | 69365c6 | 2009-08-22 13:27:40 -0400 | [diff] [blame] | 400 | struct ext2_bitmap_ops ext2fs_blkmap64_bitarray = { |
| 401 | .type = EXT2FS_BMAP64_BITARRAY, |
| 402 | .new_bmap = ba_new_bmap, |
| 403 | .free_bmap = ba_free_bmap, |
| 404 | .copy_bmap = ba_copy_bmap, |
| 405 | .resize_bmap = ba_resize_bmap, |
| 406 | .mark_bmap = ba_mark_bmap, |
| 407 | .unmark_bmap = ba_unmark_bmap, |
| 408 | .test_bmap = ba_test_bmap, |
| 409 | .test_clear_bmap_extent = ba_test_clear_bmap_extent, |
| 410 | .mark_bmap_extent = ba_mark_bmap_extent, |
| 411 | .unmark_bmap_extent = ba_unmark_bmap_extent, |
| 412 | .set_bmap_range = ba_set_bmap_range, |
| 413 | .get_bmap_range = ba_get_bmap_range, |
| 414 | .clear_bmap = ba_clear_bmap, |
Lukas Czerner | 9288e3b | 2011-12-16 17:31:07 -0500 | [diff] [blame] | 415 | .print_stats = ba_print_stats, |
Sami Liedes | 11f359f | 2012-03-10 23:38:40 +0200 | [diff] [blame] | 416 | .find_first_zero = ba_find_first_zero |
Theodore Ts'o | 69365c6 | 2009-08-22 13:27:40 -0400 | [diff] [blame] | 417 | }; |