Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Block driver for Hyper-V VHDX Images |
| 3 | * |
| 4 | * Copyright (c) 2013 Red Hat, Inc., |
| 5 | * |
| 6 | * Authors: |
| 7 | * Jeff Cody <jcody@redhat.com> |
| 8 | * |
| 9 | * This is based on the "VHDX Format Specification v1.00", published 8/25/2012 |
| 10 | * by Microsoft: |
| 11 | * https://www.microsoft.com/en-us/download/details.aspx?id=34750 |
| 12 | * |
| 13 | * This file covers the functionality of the metadata log writing, parsing, and |
| 14 | * replay. |
| 15 | * |
| 16 | * This work is licensed under the terms of the GNU LGPL, version 2 or later. |
| 17 | * See the COPYING.LIB file in the top-level directory. |
| 18 | * |
| 19 | */ |
Peter Maydell | 80c71a2 | 2016-01-18 18:01:42 +0000 | [diff] [blame] | 20 | #include "qemu/osdep.h" |
Markus Armbruster | da34e65 | 2016-03-14 09:01:28 +0100 | [diff] [blame] | 21 | #include "qapi/error.h" |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 22 | #include "qemu-common.h" |
| 23 | #include "block/block_int.h" |
Markus Armbruster | d49b683 | 2015-03-17 18:29:20 +0100 | [diff] [blame] | 24 | #include "qemu/error-report.h" |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 25 | #include "qemu/module.h" |
| 26 | #include "block/vhdx.h" |
| 27 | |
| 28 | |
| 29 | typedef struct VHDXLogSequence { |
| 30 | bool valid; |
| 31 | uint32_t count; |
| 32 | VHDXLogEntries log; |
| 33 | VHDXLogEntryHeader hdr; |
| 34 | } VHDXLogSequence; |
| 35 | |
| 36 | typedef struct VHDXLogDescEntries { |
| 37 | VHDXLogEntryHeader hdr; |
| 38 | VHDXLogDescriptor desc[]; |
| 39 | } VHDXLogDescEntries; |
| 40 | |
| 41 | static const MSGUID zero_guid = { 0 }; |
| 42 | |
| 43 | /* The log located on the disk is circular buffer containing |
| 44 | * sectors of 4096 bytes each. |
| 45 | * |
| 46 | * It is assumed for the read/write functions below that the |
| 47 | * circular buffer scheme uses a 'one sector open' to indicate |
| 48 | * the buffer is full. Given the validation methods used for each |
| 49 | * sector, this method should be compatible with other methods that |
| 50 | * do not waste a sector. |
| 51 | */ |
| 52 | |
| 53 | |
| 54 | /* Allow peeking at the hdr entry at the beginning of the current |
| 55 | * read index, without advancing the read index */ |
| 56 | static int vhdx_log_peek_hdr(BlockDriverState *bs, VHDXLogEntries *log, |
| 57 | VHDXLogEntryHeader *hdr) |
| 58 | { |
| 59 | int ret = 0; |
| 60 | uint64_t offset; |
| 61 | uint32_t read; |
| 62 | |
| 63 | assert(hdr != NULL); |
| 64 | |
| 65 | /* peek is only supported on sector boundaries */ |
| 66 | if (log->read % VHDX_LOG_SECTOR_SIZE) { |
| 67 | ret = -EFAULT; |
| 68 | goto exit; |
| 69 | } |
| 70 | |
| 71 | read = log->read; |
| 72 | /* we are guaranteed that a) log sectors are 4096 bytes, |
| 73 | * and b) the log length is a multiple of 1MB. So, there |
| 74 | * is always a round number of sectors in the buffer */ |
| 75 | if ((read + sizeof(VHDXLogEntryHeader)) > log->length) { |
| 76 | read = 0; |
| 77 | } |
| 78 | |
| 79 | if (read == log->write) { |
| 80 | ret = -EINVAL; |
| 81 | goto exit; |
| 82 | } |
| 83 | |
| 84 | offset = log->offset + read; |
| 85 | |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 86 | ret = bdrv_pread(bs->file->bs, offset, hdr, sizeof(VHDXLogEntryHeader)); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 87 | if (ret < 0) { |
| 88 | goto exit; |
| 89 | } |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 90 | vhdx_log_entry_hdr_le_import(hdr); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 91 | |
| 92 | exit: |
| 93 | return ret; |
| 94 | } |
| 95 | |
| 96 | /* Index increment for log, based on sector boundaries */ |
| 97 | static int vhdx_log_inc_idx(uint32_t idx, uint64_t length) |
| 98 | { |
| 99 | idx += VHDX_LOG_SECTOR_SIZE; |
| 100 | /* we are guaranteed that a) log sectors are 4096 bytes, |
| 101 | * and b) the log length is a multiple of 1MB. So, there |
| 102 | * is always a round number of sectors in the buffer */ |
| 103 | return idx >= length ? 0 : idx; |
| 104 | } |
| 105 | |
| 106 | |
| 107 | /* Reset the log to empty */ |
| 108 | static void vhdx_log_reset(BlockDriverState *bs, BDRVVHDXState *s) |
| 109 | { |
| 110 | MSGUID guid = { 0 }; |
| 111 | s->log.read = s->log.write = 0; |
| 112 | /* a log guid of 0 indicates an empty log to any parser of v0 |
| 113 | * VHDX logs */ |
| 114 | vhdx_update_headers(bs, s, false, &guid); |
| 115 | } |
| 116 | |
| 117 | /* Reads num_sectors from the log (all log sectors are 4096 bytes), |
| 118 | * into buffer 'buffer'. Upon return, *sectors_read will contain |
| 119 | * the number of sectors successfully read. |
| 120 | * |
| 121 | * It is assumed that 'buffer' is already allocated, and of sufficient |
| 122 | * size (i.e. >= 4096*num_sectors). |
| 123 | * |
| 124 | * If 'peek' is true, then the tail (read) pointer for the circular buffer is |
| 125 | * not modified. |
| 126 | * |
| 127 | * 0 is returned on success, -errno otherwise. */ |
| 128 | static int vhdx_log_read_sectors(BlockDriverState *bs, VHDXLogEntries *log, |
| 129 | uint32_t *sectors_read, void *buffer, |
| 130 | uint32_t num_sectors, bool peek) |
| 131 | { |
| 132 | int ret = 0; |
| 133 | uint64_t offset; |
| 134 | uint32_t read; |
| 135 | |
| 136 | read = log->read; |
| 137 | |
| 138 | *sectors_read = 0; |
| 139 | while (num_sectors) { |
| 140 | if (read == log->write) { |
| 141 | /* empty */ |
| 142 | break; |
| 143 | } |
| 144 | offset = log->offset + read; |
| 145 | |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 146 | ret = bdrv_pread(bs->file->bs, offset, buffer, VHDX_LOG_SECTOR_SIZE); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 147 | if (ret < 0) { |
| 148 | goto exit; |
| 149 | } |
| 150 | read = vhdx_log_inc_idx(read, log->length); |
| 151 | |
| 152 | *sectors_read = *sectors_read + 1; |
| 153 | num_sectors--; |
| 154 | } |
| 155 | |
| 156 | exit: |
| 157 | if (!peek) { |
| 158 | log->read = read; |
| 159 | } |
| 160 | return ret; |
| 161 | } |
| 162 | |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 163 | /* Writes num_sectors to the log (all log sectors are 4096 bytes), |
| 164 | * from buffer 'buffer'. Upon return, *sectors_written will contain |
| 165 | * the number of sectors successfully written. |
| 166 | * |
| 167 | * It is assumed that 'buffer' is at least 4096*num_sectors large. |
| 168 | * |
| 169 | * 0 is returned on success, -errno otherwise */ |
| 170 | static int vhdx_log_write_sectors(BlockDriverState *bs, VHDXLogEntries *log, |
| 171 | uint32_t *sectors_written, void *buffer, |
| 172 | uint32_t num_sectors) |
| 173 | { |
| 174 | int ret = 0; |
| 175 | uint64_t offset; |
| 176 | uint32_t write; |
| 177 | void *buffer_tmp; |
| 178 | BDRVVHDXState *s = bs->opaque; |
| 179 | |
| 180 | ret = vhdx_user_visible_write(bs, s); |
| 181 | if (ret < 0) { |
| 182 | goto exit; |
| 183 | } |
| 184 | |
| 185 | write = log->write; |
| 186 | |
| 187 | buffer_tmp = buffer; |
| 188 | while (num_sectors) { |
| 189 | |
| 190 | offset = log->offset + write; |
| 191 | write = vhdx_log_inc_idx(write, log->length); |
| 192 | if (write == log->read) { |
| 193 | /* full */ |
| 194 | break; |
| 195 | } |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 196 | ret = bdrv_pwrite(bs->file->bs, offset, buffer_tmp, |
| 197 | VHDX_LOG_SECTOR_SIZE); |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 198 | if (ret < 0) { |
| 199 | goto exit; |
| 200 | } |
| 201 | buffer_tmp += VHDX_LOG_SECTOR_SIZE; |
| 202 | |
| 203 | log->write = write; |
| 204 | *sectors_written = *sectors_written + 1; |
| 205 | num_sectors--; |
| 206 | } |
| 207 | |
| 208 | exit: |
| 209 | return ret; |
| 210 | } |
| 211 | |
| 212 | |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 213 | /* Validates a log entry header */ |
| 214 | static bool vhdx_log_hdr_is_valid(VHDXLogEntries *log, VHDXLogEntryHeader *hdr, |
| 215 | BDRVVHDXState *s) |
| 216 | { |
| 217 | int valid = false; |
| 218 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 219 | if (hdr->signature != VHDX_LOG_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 220 | goto exit; |
| 221 | } |
| 222 | |
| 223 | /* if the individual entry length is larger than the whole log |
| 224 | * buffer, that is obviously invalid */ |
| 225 | if (log->length < hdr->entry_length) { |
| 226 | goto exit; |
| 227 | } |
| 228 | |
| 229 | /* length of entire entry must be in units of 4KB (log sector size) */ |
| 230 | if (hdr->entry_length % (VHDX_LOG_SECTOR_SIZE)) { |
| 231 | goto exit; |
| 232 | } |
| 233 | |
| 234 | /* per spec, sequence # must be > 0 */ |
| 235 | if (hdr->sequence_number == 0) { |
| 236 | goto exit; |
| 237 | } |
| 238 | |
| 239 | /* log entries are only valid if they match the file-wide log guid |
| 240 | * found in the active header */ |
| 241 | if (!guid_eq(hdr->log_guid, s->headers[s->curr_header]->log_guid)) { |
| 242 | goto exit; |
| 243 | } |
| 244 | |
| 245 | if (hdr->descriptor_count * sizeof(VHDXLogDescriptor) > hdr->entry_length) { |
| 246 | goto exit; |
| 247 | } |
| 248 | |
| 249 | valid = true; |
| 250 | |
| 251 | exit: |
| 252 | return valid; |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * Given a log header, this will validate that the descriptors and the |
| 257 | * corresponding data sectors (if applicable) |
| 258 | * |
| 259 | * Validation consists of: |
| 260 | * 1. Making sure the sequence numbers matches the entry header |
| 261 | * 2. Verifying a valid signature ('zero' or 'desc' for descriptors) |
| 262 | * 3. File offset field is a multiple of 4KB |
| 263 | * 4. If a data descriptor, the corresponding data sector |
| 264 | * has its signature ('data') and matching sequence number |
| 265 | * |
| 266 | * @desc: the data buffer containing the descriptor |
| 267 | * @hdr: the log entry header |
| 268 | * |
| 269 | * Returns true if valid |
| 270 | */ |
| 271 | static bool vhdx_log_desc_is_valid(VHDXLogDescriptor *desc, |
| 272 | VHDXLogEntryHeader *hdr) |
| 273 | { |
| 274 | bool ret = false; |
| 275 | |
| 276 | if (desc->sequence_number != hdr->sequence_number) { |
| 277 | goto exit; |
| 278 | } |
| 279 | if (desc->file_offset % VHDX_LOG_SECTOR_SIZE) { |
| 280 | goto exit; |
| 281 | } |
| 282 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 283 | if (desc->signature == VHDX_LOG_ZERO_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 284 | if (desc->zero_length % VHDX_LOG_SECTOR_SIZE == 0) { |
| 285 | /* valid */ |
| 286 | ret = true; |
| 287 | } |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 288 | } else if (desc->signature == VHDX_LOG_DESC_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 289 | /* valid */ |
| 290 | ret = true; |
| 291 | } |
| 292 | |
| 293 | exit: |
| 294 | return ret; |
| 295 | } |
| 296 | |
| 297 | |
| 298 | /* Prior to sector data for a log entry, there is the header |
| 299 | * and the descriptors referenced in the header: |
| 300 | * |
| 301 | * [] = 4KB sector |
| 302 | * |
| 303 | * [ hdr, desc ][ desc ][ ... ][ data ][ ... ] |
| 304 | * |
| 305 | * The first sector in a log entry has a 64 byte header, and |
| 306 | * up to 126 32-byte descriptors. If more descriptors than |
| 307 | * 126 are required, then subsequent sectors can have up to 128 |
| 308 | * descriptors. Each sector is 4KB. Data follows the descriptor |
| 309 | * sectors. |
| 310 | * |
| 311 | * This will return the number of sectors needed to encompass |
| 312 | * the passed number of descriptors in desc_cnt. |
| 313 | * |
| 314 | * This will never return 0, even if desc_cnt is 0. |
| 315 | */ |
| 316 | static int vhdx_compute_desc_sectors(uint32_t desc_cnt) |
| 317 | { |
| 318 | uint32_t desc_sectors; |
| 319 | |
| 320 | desc_cnt += 2; /* account for header in first sector */ |
| 321 | desc_sectors = desc_cnt / 128; |
| 322 | if (desc_cnt % 128) { |
| 323 | desc_sectors++; |
| 324 | } |
| 325 | |
| 326 | return desc_sectors; |
| 327 | } |
| 328 | |
| 329 | |
| 330 | /* Reads the log header, and subsequent descriptors (if any). This |
| 331 | * will allocate all the space for buffer, which must be NULL when |
| 332 | * passed into this function. Each descriptor will also be validated, |
| 333 | * and error returned if any are invalid. */ |
| 334 | static int vhdx_log_read_desc(BlockDriverState *bs, BDRVVHDXState *s, |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 335 | VHDXLogEntries *log, VHDXLogDescEntries **buffer, |
| 336 | bool convert_endian) |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 337 | { |
| 338 | int ret = 0; |
| 339 | uint32_t desc_sectors; |
| 340 | uint32_t sectors_read; |
| 341 | VHDXLogEntryHeader hdr; |
| 342 | VHDXLogDescEntries *desc_entries = NULL; |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 343 | VHDXLogDescriptor desc; |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 344 | int i; |
| 345 | |
| 346 | assert(*buffer == NULL); |
| 347 | |
| 348 | ret = vhdx_log_peek_hdr(bs, log, &hdr); |
| 349 | if (ret < 0) { |
| 350 | goto exit; |
| 351 | } |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 352 | |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 353 | if (vhdx_log_hdr_is_valid(log, &hdr, s) == false) { |
| 354 | ret = -EINVAL; |
| 355 | goto exit; |
| 356 | } |
| 357 | |
| 358 | desc_sectors = vhdx_compute_desc_sectors(hdr.descriptor_count); |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 359 | desc_entries = qemu_try_blockalign(bs->file->bs, |
Kevin Wolf | a67e128 | 2014-05-20 13:55:50 +0200 | [diff] [blame] | 360 | desc_sectors * VHDX_LOG_SECTOR_SIZE); |
| 361 | if (desc_entries == NULL) { |
| 362 | ret = -ENOMEM; |
| 363 | goto exit; |
| 364 | } |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 365 | |
| 366 | ret = vhdx_log_read_sectors(bs, log, §ors_read, desc_entries, |
| 367 | desc_sectors, false); |
| 368 | if (ret < 0) { |
| 369 | goto free_and_exit; |
| 370 | } |
| 371 | if (sectors_read != desc_sectors) { |
| 372 | ret = -EINVAL; |
| 373 | goto free_and_exit; |
| 374 | } |
| 375 | |
| 376 | /* put in proper endianness, and validate each desc */ |
| 377 | for (i = 0; i < hdr.descriptor_count; i++) { |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 378 | desc = desc_entries->desc[i]; |
| 379 | vhdx_log_desc_le_import(&desc); |
| 380 | if (convert_endian) { |
| 381 | desc_entries->desc[i] = desc; |
| 382 | } |
| 383 | if (vhdx_log_desc_is_valid(&desc, &hdr) == false) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 384 | ret = -EINVAL; |
| 385 | goto free_and_exit; |
| 386 | } |
| 387 | } |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 388 | if (convert_endian) { |
| 389 | desc_entries->hdr = hdr; |
| 390 | } |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 391 | |
| 392 | *buffer = desc_entries; |
| 393 | goto exit; |
| 394 | |
| 395 | free_and_exit: |
| 396 | qemu_vfree(desc_entries); |
| 397 | exit: |
| 398 | return ret; |
| 399 | } |
| 400 | |
| 401 | |
| 402 | /* Flushes the descriptor described by desc to the VHDX image file. |
| 403 | * If the descriptor is a data descriptor, than 'data' must be non-NULL, |
| 404 | * and >= 4096 bytes (VHDX_LOG_SECTOR_SIZE), containing the data to be |
| 405 | * written. |
| 406 | * |
| 407 | * Verification is performed to make sure the sequence numbers of a data |
| 408 | * descriptor match the sequence number in the desc. |
| 409 | * |
| 410 | * For a zero descriptor, it may describe multiple sectors to fill with zeroes. |
| 411 | * In this case, it should be noted that zeroes are written to disk, and the |
| 412 | * image file is not extended as a sparse file. */ |
| 413 | static int vhdx_log_flush_desc(BlockDriverState *bs, VHDXLogDescriptor *desc, |
| 414 | VHDXLogDataSector *data) |
| 415 | { |
| 416 | int ret = 0; |
| 417 | uint64_t seq, file_offset; |
| 418 | uint32_t offset = 0; |
| 419 | void *buffer = NULL; |
| 420 | uint64_t count = 1; |
| 421 | int i; |
| 422 | |
| 423 | buffer = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE); |
| 424 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 425 | if (desc->signature == VHDX_LOG_DESC_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 426 | /* data sector */ |
| 427 | if (data == NULL) { |
| 428 | ret = -EFAULT; |
| 429 | goto exit; |
| 430 | } |
| 431 | |
| 432 | /* The sequence number of the data sector must match that |
| 433 | * in the descriptor */ |
| 434 | seq = data->sequence_high; |
| 435 | seq <<= 32; |
| 436 | seq |= data->sequence_low & 0xffffffff; |
| 437 | |
| 438 | if (seq != desc->sequence_number) { |
| 439 | ret = -EINVAL; |
| 440 | goto exit; |
| 441 | } |
| 442 | |
| 443 | /* Each data sector is in total 4096 bytes, however the first |
| 444 | * 8 bytes, and last 4 bytes, are located in the descriptor */ |
| 445 | memcpy(buffer, &desc->leading_bytes, 8); |
| 446 | offset += 8; |
| 447 | |
| 448 | memcpy(buffer+offset, data->data, 4084); |
| 449 | offset += 4084; |
| 450 | |
| 451 | memcpy(buffer+offset, &desc->trailing_bytes, 4); |
| 452 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 453 | } else if (desc->signature == VHDX_LOG_ZERO_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 454 | /* write 'count' sectors of sector */ |
| 455 | memset(buffer, 0, VHDX_LOG_SECTOR_SIZE); |
| 456 | count = desc->zero_length / VHDX_LOG_SECTOR_SIZE; |
Jeff Cody | 349592e | 2014-08-06 15:54:57 -0400 | [diff] [blame] | 457 | } else { |
| 458 | error_report("Invalid VHDX log descriptor entry signature 0x%" PRIx32, |
| 459 | desc->signature); |
| 460 | ret = -EINVAL; |
| 461 | goto exit; |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 462 | } |
| 463 | |
| 464 | file_offset = desc->file_offset; |
| 465 | |
| 466 | /* count is only > 1 if we are writing zeroes */ |
| 467 | for (i = 0; i < count; i++) { |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 468 | ret = bdrv_pwrite_sync(bs->file->bs, file_offset, buffer, |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 469 | VHDX_LOG_SECTOR_SIZE); |
| 470 | if (ret < 0) { |
| 471 | goto exit; |
| 472 | } |
| 473 | file_offset += VHDX_LOG_SECTOR_SIZE; |
| 474 | } |
| 475 | |
| 476 | exit: |
| 477 | qemu_vfree(buffer); |
| 478 | return ret; |
| 479 | } |
| 480 | |
| 481 | /* Flush the entire log (as described by 'logs') to the VHDX image |
| 482 | * file, and then set the log to 'empty' status once complete. |
| 483 | * |
| 484 | * The log entries should be validate prior to flushing */ |
| 485 | static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s, |
| 486 | VHDXLogSequence *logs) |
| 487 | { |
| 488 | int ret = 0; |
| 489 | int i; |
| 490 | uint32_t cnt, sectors_read; |
| 491 | uint64_t new_file_size; |
| 492 | void *data = NULL; |
| 493 | VHDXLogDescEntries *desc_entries = NULL; |
| 494 | VHDXLogEntryHeader hdr_tmp = { 0 }; |
| 495 | |
| 496 | cnt = logs->count; |
| 497 | |
| 498 | data = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE); |
| 499 | |
| 500 | ret = vhdx_user_visible_write(bs, s); |
| 501 | if (ret < 0) { |
| 502 | goto exit; |
| 503 | } |
| 504 | |
| 505 | /* each iteration represents one log sequence, which may span multiple |
| 506 | * sectors */ |
| 507 | while (cnt--) { |
| 508 | ret = vhdx_log_peek_hdr(bs, &logs->log, &hdr_tmp); |
| 509 | if (ret < 0) { |
| 510 | goto exit; |
| 511 | } |
| 512 | /* if the log shows a FlushedFileOffset larger than our current file |
| 513 | * size, then that means the file has been truncated / corrupted, and |
| 514 | * we must refused to open it / use it */ |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 515 | if (hdr_tmp.flushed_file_offset > bdrv_getlength(bs->file->bs)) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 516 | ret = -EINVAL; |
| 517 | goto exit; |
| 518 | } |
| 519 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 520 | ret = vhdx_log_read_desc(bs, s, &logs->log, &desc_entries, true); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 521 | if (ret < 0) { |
| 522 | goto exit; |
| 523 | } |
| 524 | |
| 525 | for (i = 0; i < desc_entries->hdr.descriptor_count; i++) { |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 526 | if (desc_entries->desc[i].signature == VHDX_LOG_DESC_SIGNATURE) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 527 | /* data sector, so read a sector to flush */ |
| 528 | ret = vhdx_log_read_sectors(bs, &logs->log, §ors_read, |
| 529 | data, 1, false); |
| 530 | if (ret < 0) { |
| 531 | goto exit; |
| 532 | } |
| 533 | if (sectors_read != 1) { |
| 534 | ret = -EINVAL; |
| 535 | goto exit; |
| 536 | } |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 537 | vhdx_log_data_le_import(data); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 538 | } |
| 539 | |
| 540 | ret = vhdx_log_flush_desc(bs, &desc_entries->desc[i], data); |
| 541 | if (ret < 0) { |
| 542 | goto exit; |
| 543 | } |
| 544 | } |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 545 | if (bdrv_getlength(bs->file->bs) < desc_entries->hdr.last_file_offset) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 546 | new_file_size = desc_entries->hdr.last_file_offset; |
| 547 | if (new_file_size % (1024*1024)) { |
| 548 | /* round up to nearest 1MB boundary */ |
| 549 | new_file_size = ((new_file_size >> 20) + 1) << 20; |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 550 | bdrv_truncate(bs->file->bs, new_file_size); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 551 | } |
| 552 | } |
| 553 | qemu_vfree(desc_entries); |
| 554 | desc_entries = NULL; |
| 555 | } |
| 556 | |
| 557 | bdrv_flush(bs); |
| 558 | /* once the log is fully flushed, indicate that we have an empty log |
| 559 | * now. This also sets the log guid to 0, to indicate an empty log */ |
| 560 | vhdx_log_reset(bs, s); |
| 561 | |
| 562 | exit: |
| 563 | qemu_vfree(data); |
| 564 | qemu_vfree(desc_entries); |
| 565 | return ret; |
| 566 | } |
| 567 | |
| 568 | static int vhdx_validate_log_entry(BlockDriverState *bs, BDRVVHDXState *s, |
| 569 | VHDXLogEntries *log, uint64_t seq, |
| 570 | bool *valid, VHDXLogEntryHeader *entry) |
| 571 | { |
| 572 | int ret = 0; |
| 573 | VHDXLogEntryHeader hdr; |
| 574 | void *buffer = NULL; |
| 575 | uint32_t i, desc_sectors, total_sectors, crc; |
| 576 | uint32_t sectors_read = 0; |
| 577 | VHDXLogDescEntries *desc_buffer = NULL; |
| 578 | |
| 579 | *valid = false; |
| 580 | |
| 581 | ret = vhdx_log_peek_hdr(bs, log, &hdr); |
| 582 | if (ret < 0) { |
| 583 | goto inc_and_exit; |
| 584 | } |
| 585 | |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 586 | if (vhdx_log_hdr_is_valid(log, &hdr, s) == false) { |
| 587 | goto inc_and_exit; |
| 588 | } |
| 589 | |
| 590 | if (seq > 0) { |
| 591 | if (hdr.sequence_number != seq + 1) { |
| 592 | goto inc_and_exit; |
| 593 | } |
| 594 | } |
| 595 | |
| 596 | desc_sectors = vhdx_compute_desc_sectors(hdr.descriptor_count); |
| 597 | |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 598 | /* Read all log sectors, and calculate log checksum */ |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 599 | |
| 600 | total_sectors = hdr.entry_length / VHDX_LOG_SECTOR_SIZE; |
| 601 | |
| 602 | |
Deepak Kathayat | dc6fb73 | 2014-03-24 16:30:17 +0800 | [diff] [blame] | 603 | /* read_desc() will increment the read idx */ |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 604 | ret = vhdx_log_read_desc(bs, s, log, &desc_buffer, false); |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 605 | if (ret < 0) { |
| 606 | goto free_and_exit; |
| 607 | } |
| 608 | |
| 609 | crc = vhdx_checksum_calc(0xffffffff, (void *)desc_buffer, |
| 610 | desc_sectors * VHDX_LOG_SECTOR_SIZE, 4); |
| 611 | crc ^= 0xffffffff; |
| 612 | |
| 613 | buffer = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE); |
| 614 | if (total_sectors > desc_sectors) { |
| 615 | for (i = 0; i < total_sectors - desc_sectors; i++) { |
| 616 | sectors_read = 0; |
| 617 | ret = vhdx_log_read_sectors(bs, log, §ors_read, buffer, |
| 618 | 1, false); |
| 619 | if (ret < 0 || sectors_read != 1) { |
| 620 | goto free_and_exit; |
| 621 | } |
| 622 | crc = vhdx_checksum_calc(crc, buffer, VHDX_LOG_SECTOR_SIZE, -1); |
| 623 | crc ^= 0xffffffff; |
| 624 | } |
| 625 | } |
| 626 | crc ^= 0xffffffff; |
Jeff Cody | 4f75b52 | 2014-08-06 15:54:58 -0400 | [diff] [blame] | 627 | if (crc != hdr.checksum) { |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 628 | goto free_and_exit; |
| 629 | } |
| 630 | |
| 631 | *valid = true; |
| 632 | *entry = hdr; |
| 633 | goto free_and_exit; |
| 634 | |
| 635 | inc_and_exit: |
| 636 | log->read = vhdx_log_inc_idx(log->read, log->length); |
| 637 | |
| 638 | free_and_exit: |
| 639 | qemu_vfree(buffer); |
| 640 | qemu_vfree(desc_buffer); |
| 641 | return ret; |
| 642 | } |
| 643 | |
| 644 | /* Search through the log circular buffer, and find the valid, active |
| 645 | * log sequence, if any exists |
| 646 | * */ |
| 647 | static int vhdx_log_search(BlockDriverState *bs, BDRVVHDXState *s, |
| 648 | VHDXLogSequence *logs) |
| 649 | { |
| 650 | int ret = 0; |
| 651 | uint32_t tail; |
| 652 | bool seq_valid = false; |
| 653 | VHDXLogSequence candidate = { 0 }; |
| 654 | VHDXLogEntryHeader hdr = { 0 }; |
| 655 | VHDXLogEntries curr_log; |
| 656 | |
| 657 | memcpy(&curr_log, &s->log, sizeof(VHDXLogEntries)); |
| 658 | curr_log.write = curr_log.length; /* assume log is full */ |
| 659 | curr_log.read = 0; |
| 660 | |
| 661 | |
| 662 | /* now we will go through the whole log sector by sector, until |
| 663 | * we find a valid, active log sequence, or reach the end of the |
| 664 | * log buffer */ |
| 665 | for (;;) { |
| 666 | uint64_t curr_seq = 0; |
| 667 | VHDXLogSequence current = { 0 }; |
| 668 | |
| 669 | tail = curr_log.read; |
| 670 | |
| 671 | ret = vhdx_validate_log_entry(bs, s, &curr_log, curr_seq, |
| 672 | &seq_valid, &hdr); |
| 673 | if (ret < 0) { |
| 674 | goto exit; |
| 675 | } |
| 676 | |
| 677 | if (seq_valid) { |
| 678 | current.valid = true; |
| 679 | current.log = curr_log; |
| 680 | current.log.read = tail; |
| 681 | current.log.write = curr_log.read; |
| 682 | current.count = 1; |
| 683 | current.hdr = hdr; |
| 684 | |
| 685 | |
| 686 | for (;;) { |
| 687 | ret = vhdx_validate_log_entry(bs, s, &curr_log, curr_seq, |
| 688 | &seq_valid, &hdr); |
| 689 | if (ret < 0) { |
| 690 | goto exit; |
| 691 | } |
| 692 | if (seq_valid == false) { |
| 693 | break; |
| 694 | } |
| 695 | current.log.write = curr_log.read; |
| 696 | current.count++; |
| 697 | |
| 698 | curr_seq = hdr.sequence_number; |
| 699 | } |
| 700 | } |
| 701 | |
| 702 | if (current.valid) { |
| 703 | if (candidate.valid == false || |
| 704 | current.hdr.sequence_number > candidate.hdr.sequence_number) { |
| 705 | candidate = current; |
| 706 | } |
| 707 | } |
| 708 | |
| 709 | if (curr_log.read < tail) { |
| 710 | break; |
| 711 | } |
| 712 | } |
| 713 | |
| 714 | *logs = candidate; |
| 715 | |
| 716 | if (candidate.valid) { |
| 717 | /* this is the next sequence number, for writes */ |
| 718 | s->log.sequence = candidate.hdr.sequence_number + 1; |
| 719 | } |
| 720 | |
| 721 | |
| 722 | exit: |
| 723 | return ret; |
| 724 | } |
| 725 | |
| 726 | /* Parse the replay log. Per the VHDX spec, if the log is present |
| 727 | * it must be replayed prior to opening the file, even read-only. |
| 728 | * |
| 729 | * If read-only, we must replay the log in RAM (or refuse to open |
| 730 | * a dirty VHDX file read-only) */ |
Jeff Cody | 7e30e6a | 2013-12-17 05:33:37 -0500 | [diff] [blame] | 731 | int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed, |
| 732 | Error **errp) |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 733 | { |
| 734 | int ret = 0; |
| 735 | VHDXHeader *hdr; |
| 736 | VHDXLogSequence logs = { 0 }; |
| 737 | |
| 738 | hdr = s->headers[s->curr_header]; |
| 739 | |
| 740 | *flushed = false; |
| 741 | |
| 742 | /* s->log.hdr is freed in vhdx_close() */ |
| 743 | if (s->log.hdr == NULL) { |
| 744 | s->log.hdr = qemu_blockalign(bs, sizeof(VHDXLogEntryHeader)); |
| 745 | } |
| 746 | |
| 747 | s->log.offset = hdr->log_offset; |
| 748 | s->log.length = hdr->log_length; |
| 749 | |
| 750 | if (s->log.offset < VHDX_LOG_MIN_SIZE || |
| 751 | s->log.offset % VHDX_LOG_MIN_SIZE) { |
| 752 | ret = -EINVAL; |
| 753 | goto exit; |
| 754 | } |
| 755 | |
| 756 | /* per spec, only log version of 0 is supported */ |
| 757 | if (hdr->log_version != 0) { |
| 758 | ret = -EINVAL; |
| 759 | goto exit; |
| 760 | } |
| 761 | |
| 762 | /* If either the log guid, or log length is zero, |
| 763 | * then a replay log is not present */ |
| 764 | if (guid_eq(hdr->log_guid, zero_guid)) { |
| 765 | goto exit; |
| 766 | } |
| 767 | |
| 768 | if (hdr->log_length == 0) { |
| 769 | goto exit; |
| 770 | } |
| 771 | |
| 772 | if (hdr->log_length % VHDX_LOG_MIN_SIZE) { |
| 773 | ret = -EINVAL; |
| 774 | goto exit; |
| 775 | } |
| 776 | |
| 777 | |
| 778 | /* The log is present, we need to find if and where there is an active |
| 779 | * sequence of valid entries present in the log. */ |
| 780 | |
| 781 | ret = vhdx_log_search(bs, s, &logs); |
| 782 | if (ret < 0) { |
| 783 | goto exit; |
| 784 | } |
| 785 | |
| 786 | if (logs.valid) { |
Jeff Cody | 7e30e6a | 2013-12-17 05:33:37 -0500 | [diff] [blame] | 787 | if (bs->read_only) { |
| 788 | ret = -EPERM; |
Markus Armbruster | bf89e87 | 2015-12-18 16:35:23 +0100 | [diff] [blame] | 789 | error_setg(errp, |
| 790 | "VHDX image file '%s' opened read-only, but " |
| 791 | "contains a log that needs to be replayed", |
| 792 | bs->filename); |
| 793 | error_append_hint(errp, "To replay the log, run:\n" |
| 794 | "qemu-img check -r all '%s'\n", |
| 795 | bs->filename); |
Jeff Cody | 7e30e6a | 2013-12-17 05:33:37 -0500 | [diff] [blame] | 796 | goto exit; |
| 797 | } |
Jeff Cody | 0a43a1b | 2013-10-30 10:44:45 -0400 | [diff] [blame] | 798 | /* now flush the log */ |
| 799 | ret = vhdx_log_flush(bs, s, &logs); |
| 800 | if (ret < 0) { |
| 801 | goto exit; |
| 802 | } |
| 803 | *flushed = true; |
| 804 | } |
| 805 | |
| 806 | |
| 807 | exit: |
| 808 | return ret; |
| 809 | } |
| 810 | |
| 811 | |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 812 | |
| 813 | static void vhdx_log_raw_to_le_sector(VHDXLogDescriptor *desc, |
| 814 | VHDXLogDataSector *sector, void *data, |
| 815 | uint64_t seq) |
| 816 | { |
| 817 | /* 8 + 4084 + 4 = 4096, 1 log sector */ |
| 818 | memcpy(&desc->leading_bytes, data, 8); |
| 819 | data += 8; |
| 820 | cpu_to_le64s(&desc->leading_bytes); |
| 821 | memcpy(sector->data, data, 4084); |
| 822 | data += 4084; |
| 823 | memcpy(&desc->trailing_bytes, data, 4); |
| 824 | cpu_to_le32s(&desc->trailing_bytes); |
| 825 | data += 4; |
| 826 | |
| 827 | sector->sequence_high = (uint32_t) (seq >> 32); |
| 828 | sector->sequence_low = (uint32_t) (seq & 0xffffffff); |
| 829 | sector->data_signature = VHDX_LOG_DATA_SIGNATURE; |
| 830 | |
| 831 | vhdx_log_desc_le_export(desc); |
| 832 | vhdx_log_data_le_export(sector); |
| 833 | } |
| 834 | |
| 835 | |
| 836 | static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s, |
| 837 | void *data, uint32_t length, uint64_t offset) |
| 838 | { |
| 839 | int ret = 0; |
| 840 | void *buffer = NULL; |
| 841 | void *merged_sector = NULL; |
| 842 | void *data_tmp, *sector_write; |
| 843 | unsigned int i; |
| 844 | int sector_offset; |
| 845 | uint32_t desc_sectors, sectors, total_length; |
| 846 | uint32_t sectors_written = 0; |
| 847 | uint32_t aligned_length; |
| 848 | uint32_t leading_length = 0; |
| 849 | uint32_t trailing_length = 0; |
| 850 | uint32_t partial_sectors = 0; |
| 851 | uint32_t bytes_written = 0; |
| 852 | uint64_t file_offset; |
| 853 | VHDXHeader *header; |
| 854 | VHDXLogEntryHeader new_hdr; |
| 855 | VHDXLogDescriptor *new_desc = NULL; |
| 856 | VHDXLogDataSector *data_sector = NULL; |
| 857 | MSGUID new_guid = { 0 }; |
| 858 | |
| 859 | header = s->headers[s->curr_header]; |
| 860 | |
| 861 | /* need to have offset read data, and be on 4096 byte boundary */ |
| 862 | |
| 863 | if (length > header->log_length) { |
| 864 | /* no log present. we could create a log here instead of failing */ |
| 865 | ret = -EINVAL; |
| 866 | goto exit; |
| 867 | } |
| 868 | |
| 869 | if (guid_eq(header->log_guid, zero_guid)) { |
| 870 | vhdx_guid_generate(&new_guid); |
| 871 | vhdx_update_headers(bs, s, false, &new_guid); |
| 872 | } else { |
| 873 | /* currently, we require that the log be flushed after |
| 874 | * every write. */ |
| 875 | ret = -ENOTSUP; |
| 876 | goto exit; |
| 877 | } |
| 878 | |
| 879 | /* 0 is an invalid sequence number, but may also represent the first |
| 880 | * log write (or a wrapped seq) */ |
| 881 | if (s->log.sequence == 0) { |
| 882 | s->log.sequence = 1; |
| 883 | } |
| 884 | |
| 885 | sector_offset = offset % VHDX_LOG_SECTOR_SIZE; |
| 886 | file_offset = (offset / VHDX_LOG_SECTOR_SIZE) * VHDX_LOG_SECTOR_SIZE; |
| 887 | |
| 888 | aligned_length = length; |
| 889 | |
| 890 | /* add in the unaligned head and tail bytes */ |
| 891 | if (sector_offset) { |
| 892 | leading_length = (VHDX_LOG_SECTOR_SIZE - sector_offset); |
| 893 | leading_length = leading_length > length ? length : leading_length; |
| 894 | aligned_length -= leading_length; |
| 895 | partial_sectors++; |
| 896 | } |
| 897 | |
| 898 | sectors = aligned_length / VHDX_LOG_SECTOR_SIZE; |
| 899 | trailing_length = aligned_length - (sectors * VHDX_LOG_SECTOR_SIZE); |
| 900 | if (trailing_length) { |
| 901 | partial_sectors++; |
| 902 | } |
| 903 | |
| 904 | sectors += partial_sectors; |
| 905 | |
| 906 | /* sectors is now how many sectors the data itself takes, not |
| 907 | * including the header and descriptor metadata */ |
| 908 | |
| 909 | new_hdr = (VHDXLogEntryHeader) { |
| 910 | .signature = VHDX_LOG_SIGNATURE, |
| 911 | .tail = s->log.tail, |
| 912 | .sequence_number = s->log.sequence, |
| 913 | .descriptor_count = sectors, |
| 914 | .reserved = 0, |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 915 | .flushed_file_offset = bdrv_getlength(bs->file->bs), |
| 916 | .last_file_offset = bdrv_getlength(bs->file->bs), |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 917 | }; |
| 918 | |
| 919 | new_hdr.log_guid = header->log_guid; |
| 920 | |
| 921 | desc_sectors = vhdx_compute_desc_sectors(new_hdr.descriptor_count); |
| 922 | |
| 923 | total_length = (desc_sectors + sectors) * VHDX_LOG_SECTOR_SIZE; |
| 924 | new_hdr.entry_length = total_length; |
| 925 | |
| 926 | vhdx_log_entry_hdr_le_export(&new_hdr); |
| 927 | |
| 928 | buffer = qemu_blockalign(bs, total_length); |
| 929 | memcpy(buffer, &new_hdr, sizeof(new_hdr)); |
| 930 | |
Markus Armbruster | d4df3db | 2014-08-19 10:31:11 +0200 | [diff] [blame] | 931 | new_desc = buffer + sizeof(new_hdr); |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 932 | data_sector = buffer + (desc_sectors * VHDX_LOG_SECTOR_SIZE); |
| 933 | data_tmp = data; |
| 934 | |
| 935 | /* All log sectors are 4KB, so for any partial sectors we must |
| 936 | * merge the data with preexisting data from the final file |
| 937 | * destination */ |
| 938 | merged_sector = qemu_blockalign(bs, VHDX_LOG_SECTOR_SIZE); |
| 939 | |
| 940 | for (i = 0; i < sectors; i++) { |
| 941 | new_desc->signature = VHDX_LOG_DESC_SIGNATURE; |
| 942 | new_desc->sequence_number = s->log.sequence; |
| 943 | new_desc->file_offset = file_offset; |
| 944 | |
| 945 | if (i == 0 && leading_length) { |
| 946 | /* partial sector at the front of the buffer */ |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 947 | ret = bdrv_pread(bs->file->bs, file_offset, merged_sector, |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 948 | VHDX_LOG_SECTOR_SIZE); |
| 949 | if (ret < 0) { |
| 950 | goto exit; |
| 951 | } |
| 952 | memcpy(merged_sector + sector_offset, data_tmp, leading_length); |
| 953 | bytes_written = leading_length; |
| 954 | sector_write = merged_sector; |
| 955 | } else if (i == sectors - 1 && trailing_length) { |
| 956 | /* partial sector at the end of the buffer */ |
Kevin Wolf | 9a4f4c3 | 2015-06-16 14:19:22 +0200 | [diff] [blame] | 957 | ret = bdrv_pread(bs->file->bs, |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 958 | file_offset, |
| 959 | merged_sector + trailing_length, |
| 960 | VHDX_LOG_SECTOR_SIZE - trailing_length); |
| 961 | if (ret < 0) { |
| 962 | goto exit; |
| 963 | } |
| 964 | memcpy(merged_sector, data_tmp, trailing_length); |
| 965 | bytes_written = trailing_length; |
| 966 | sector_write = merged_sector; |
| 967 | } else { |
| 968 | bytes_written = VHDX_LOG_SECTOR_SIZE; |
| 969 | sector_write = data_tmp; |
| 970 | } |
| 971 | |
| 972 | /* populate the raw sector data into the proper structures, |
| 973 | * as well as update the descriptor, and convert to proper |
| 974 | * endianness */ |
| 975 | vhdx_log_raw_to_le_sector(new_desc, data_sector, sector_write, |
| 976 | s->log.sequence); |
| 977 | |
| 978 | data_tmp += bytes_written; |
| 979 | data_sector++; |
| 980 | new_desc++; |
| 981 | file_offset += VHDX_LOG_SECTOR_SIZE; |
| 982 | } |
| 983 | |
| 984 | /* checksum covers entire entry, from the log header through the |
| 985 | * last data sector */ |
| 986 | vhdx_update_checksum(buffer, total_length, |
| 987 | offsetof(VHDXLogEntryHeader, checksum)); |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 988 | |
| 989 | /* now write to the log */ |
Markus Armbruster | f50159f | 2014-01-29 18:05:08 +0100 | [diff] [blame] | 990 | ret = vhdx_log_write_sectors(bs, &s->log, §ors_written, buffer, |
| 991 | desc_sectors + sectors); |
Jeff Cody | 8adc523 | 2013-10-30 10:44:47 -0400 | [diff] [blame] | 992 | if (ret < 0) { |
| 993 | goto exit; |
| 994 | } |
| 995 | |
| 996 | if (sectors_written != desc_sectors + sectors) { |
| 997 | /* instead of failing, we could flush the log here */ |
| 998 | ret = -EINVAL; |
| 999 | goto exit; |
| 1000 | } |
| 1001 | |
| 1002 | s->log.sequence++; |
| 1003 | /* write new tail */ |
| 1004 | s->log.tail = s->log.write; |
| 1005 | |
| 1006 | exit: |
| 1007 | qemu_vfree(buffer); |
| 1008 | qemu_vfree(merged_sector); |
| 1009 | return ret; |
| 1010 | } |
| 1011 | |
| 1012 | /* Perform a log write, and then immediately flush the entire log */ |
| 1013 | int vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s, |
| 1014 | void *data, uint32_t length, uint64_t offset) |
| 1015 | { |
| 1016 | int ret = 0; |
| 1017 | VHDXLogSequence logs = { .valid = true, |
| 1018 | .count = 1, |
| 1019 | .hdr = { 0 } }; |
| 1020 | |
| 1021 | |
| 1022 | /* Make sure data written (new and/or changed blocks) is stable |
| 1023 | * on disk, before creating log entry */ |
| 1024 | bdrv_flush(bs); |
| 1025 | ret = vhdx_log_write(bs, s, data, length, offset); |
| 1026 | if (ret < 0) { |
| 1027 | goto exit; |
| 1028 | } |
| 1029 | logs.log = s->log; |
| 1030 | |
| 1031 | /* Make sure log is stable on disk */ |
| 1032 | bdrv_flush(bs); |
| 1033 | ret = vhdx_log_flush(bs, s, &logs); |
| 1034 | if (ret < 0) { |
| 1035 | goto exit; |
| 1036 | } |
| 1037 | |
| 1038 | s->log = logs.log; |
| 1039 | |
| 1040 | exit: |
| 1041 | return ret; |
| 1042 | } |
| 1043 | |