block/blkverify.c

   1 /*
   2  * Block protocol for block driver correctness testing
   3  *
   4  * Copyright (C) 2010 IBM, Corp.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #include <stdarg.h>
  11 #include "qemu/sockets.h" /* for EINPROGRESS on Windows */
  12 #include "block/block_int.h"
  13
  14 typedef struct {
  15     BlockDriverState *test_file;
  16 } BDRVBlkverifyState;
  17
  18 typedef struct BlkverifyAIOCB BlkverifyAIOCB;
  19 struct BlkverifyAIOCB {
  20     BlockDriverAIOCB common;
  21     QEMUBH *bh;
  22
  23     /* Request metadata */
  24     bool is_write;
  25     int64_t sector_num;
  26     int nb_sectors;
  27
  28     int ret;                    /* first completed request's result */
  29     unsigned int done;          /* completion counter */
  30     bool *finished;             /* completion signal for cancel */
  31
  32     QEMUIOVector *qiov;         /* user I/O vector */
  33     QEMUIOVector raw_qiov;      /* cloned I/O vector for raw file */
  34     void *buf;                  /* buffer for raw file I/O */
  35
  36     void (*verify)(BlkverifyAIOCB *acb);
  37 };
  38
  39 static void blkverify_aio_cancel(BlockDriverAIOCB *blockacb)
  40 {
  41     BlkverifyAIOCB *acb = (BlkverifyAIOCB *)blockacb;
  42     bool finished = false;
  43
  44     /* Wait until request completes, invokes its callback, and frees itself */
  45     acb->finished = &finished;
  46     while (!finished) {
  47         qemu_aio_wait();
  48     }
  49 }
  50
  51 static const AIOCBInfo blkverify_aiocb_info = {
  52     .aiocb_size         = sizeof(BlkverifyAIOCB),
  53     .cancel             = blkverify_aio_cancel,
  54 };
  55
  56 static void GCC_FMT_ATTR(2, 3) blkverify_err(BlkverifyAIOCB *acb,
  57                                              const char *fmt, ...)
  58 {
  59     va_list ap;
  60
  61     va_start(ap, fmt);
  62     fprintf(stderr, "blkverify: %s sector_num=%" PRId64 " nb_sectors=%d ",
  63             acb->is_write ? "write" : "read", acb->sector_num,
  64             acb->nb_sectors);
  65     vfprintf(stderr, fmt, ap);
  66     fprintf(stderr, "\n");
  67     va_end(ap);
  68     exit(1);
  69 }
  70
  71 /* Valid blkverify filenames look like blkverify:path/to/raw_image:path/to/image */
  72 static void blkverify_parse_filename(const char *filename, QDict *options,
  73                                      Error **errp)
  74 {
  75     const char *c;
  76     QString *raw_path;
  77
  78
  79     /* Parse the blkverify: prefix */
  80     if (!strstart(filename, "blkverify:", &filename)) {
  81         error_setg(errp, "File name string must start with 'blkverify:'");
  82         return;
  83     }
  84
  85     /* Parse the raw image filename */
  86     c = strchr(filename, ':');
  87     if (c == NULL) {
  88         error_setg(errp, "blkverify requires raw copy and original image path");
  89         return;
  90     }
  91
  92     /* TODO Implement option pass-through and set raw.filename here */
  93     raw_path = qstring_from_substr(filename, 0, c - filename - 1);
  94     qdict_put(options, "x-raw", raw_path);
  95
  96     /* TODO Allow multi-level nesting and set file.filename here */
  97     filename = c + 1;
  98     qdict_put(options, "x-image", qstring_from_str(filename));
  99 }
 100
 101 static QemuOptsList runtime_opts = {
 102     .name = "blkverify",
 103     .head = QTAILQ_HEAD_INITIALIZER(runtime_opts.head),
 104     .desc = {
 105         {
 106             .name = "x-raw",
 107             .type = QEMU_OPT_STRING,
 108             .help = "[internal use only, will be removed]",
 109         },
 110         {
 111             .name = "x-image",
 112             .type = QEMU_OPT_STRING,
 113             .help = "[internal use only, will be removed]",
 114         },
 115         { /* end of list */ }
 116     },
 117 };
 118
 119 static int blkverify_open(BlockDriverState *bs, QDict *options, int flags,
 120                           Error **errp)
 121 {
 122     BDRVBlkverifyState *s = bs->opaque;
 123     QemuOpts *opts;
 124     Error *local_err = NULL;
 125     const char *filename, *raw;
 126     int ret;
 127
 128     opts = qemu_opts_create_nofail(&runtime_opts);
 129     qemu_opts_absorb_qdict(opts, options, &local_err);
 130     if (error_is_set(&local_err)) {
 131         qerror_report_err(local_err);
 132         error_free(local_err);
 133         ret = -EINVAL;
 134         goto fail;
 135     }
 136
 137     /* Parse the raw image filename */
 138     raw = qemu_opt_get(opts, "x-raw");
 139     if (raw == NULL) {
 140         ret = -EINVAL;
 141         goto fail;
 142     }
 143
 144     ret = bdrv_file_open(&bs->file, raw, NULL, flags, &local_err);
 145     if (ret < 0) {
 146         qerror_report_err(local_err);
 147         error_free(local_err);
 148         goto fail;
 149     }
 150
 151     /* Open the test file */
 152     filename = qemu_opt_get(opts, "x-image");
 153     if (filename == NULL) {
 154         ret = -EINVAL;
 155         goto fail;
 156     }
 157
 158     s->test_file = bdrv_new("");
 159     ret = bdrv_open(s->test_file, filename, NULL, flags, NULL, &local_err);
 160     if (ret < 0) {
 161         qerror_report_err(local_err);
 162         error_free(local_err);
 163         bdrv_unref(s->test_file);
 164         s->test_file = NULL;
 165         goto fail;
 166     }
 167
 168     ret = 0;
 169 fail:
 170     return ret;
 171 }
 172
 173 static void blkverify_close(BlockDriverState *bs)
 174 {
 175     BDRVBlkverifyState *s = bs->opaque;
 176
 177     bdrv_unref(s->test_file);
 178     s->test_file = NULL;
 179 }
 180
 181 static int64_t blkverify_getlength(BlockDriverState *bs)
 182 {
 183     BDRVBlkverifyState *s = bs->opaque;
 184
 185     return bdrv_getlength(s->test_file);
 186 }
 187
 188 /**
 189  * Check that I/O vector contents are identical
 190  *
 191  * @a:          I/O vector
 192  * @b:          I/O vector
 193  * @ret:        Offset to first mismatching byte or -1 if match
 194  */
 195 static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
 196 {
 197     int i;
 198     ssize_t offset = 0;
 199
 200     assert(a->niov == b->niov);
 201     for (i = 0; i < a->niov; i++) {
 202         size_t len = 0;
 203         uint8_t *p = (uint8_t *)a->iov[i].iov_base;
 204         uint8_t *q = (uint8_t *)b->iov[i].iov_base;
 205
 206         assert(a->iov[i].iov_len == b->iov[i].iov_len);
 207         while (len < a->iov[i].iov_len && *p++ == *q++) {
 208             len++;
 209         }
 210
 211         offset += len;
 212
 213         if (len != a->iov[i].iov_len) {
 214             return offset;
 215         }
 216     }
 217     return -1;
 218 }
 219
 220 typedef struct {
 221     int src_index;
 222     struct iovec *src_iov;
 223     void *dest_base;
 224 } IOVectorSortElem;
 225
 226 static int sortelem_cmp_src_base(const void *a, const void *b)
 227 {
 228     const IOVectorSortElem *elem_a = a;
 229     const IOVectorSortElem *elem_b = b;
 230
 231     /* Don't overflow */
 232     if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
 233         return -1;
 234     } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
 235         return 1;
 236     } else {
 237         return 0;
 238     }
 239 }
 240
 241 static int sortelem_cmp_src_index(const void *a, const void *b)
 242 {
 243     const IOVectorSortElem *elem_a = a;
 244     const IOVectorSortElem *elem_b = b;
 245
 246     return elem_a->src_index - elem_b->src_index;
 247 }
 248
 249 /**
 250  * Copy contents of I/O vector
 251  *
 252  * The relative relationships of overlapping iovecs are preserved.  This is
 253  * necessary to ensure identical semantics in the cloned I/O vector.
 254  */
 255 static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,
 256                                   void *buf)
 257 {
 258     IOVectorSortElem sortelems[src->niov];
 259     void *last_end;
 260     int i;
 261
 262     /* Sort by source iovecs by base address */
 263     for (i = 0; i < src->niov; i++) {
 264         sortelems[i].src_index = i;
 265         sortelems[i].src_iov = &src->iov[i];
 266     }
 267     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
 268
 269     /* Allocate buffer space taking into account overlapping iovecs */
 270     last_end = NULL;
 271     for (i = 0; i < src->niov; i++) {
 272         struct iovec *cur = sortelems[i].src_iov;
 273         ptrdiff_t rewind = 0;
 274
 275         /* Detect overlap */
 276         if (last_end && last_end > cur->iov_base) {
 277             rewind = last_end - cur->iov_base;
 278         }
 279
 280         sortelems[i].dest_base = buf - rewind;
 281         buf += cur->iov_len - MIN(rewind, cur->iov_len);
 282         last_end = MAX(cur->iov_base + cur->iov_len, last_end);
 283     }
 284
 285     /* Sort by source iovec index and build destination iovec */
 286     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
 287     for (i = 0; i < src->niov; i++) {
 288         qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
 289     }
 290 }
 291
 292 static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
 293                                          int64_t sector_num, QEMUIOVector *qiov,
 294                                          int nb_sectors,
 295                                          BlockDriverCompletionFunc *cb,
 296                                          void *opaque)
 297 {
 298     BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aiocb_info, bs, cb, opaque);
 299
 300     acb->bh = NULL;
 301     acb->is_write = is_write;
 302     acb->sector_num = sector_num;
 303     acb->nb_sectors = nb_sectors;
 304     acb->ret = -EINPROGRESS;
 305     acb->done = 0;
 306     acb->qiov = qiov;
 307     acb->buf = NULL;
 308     acb->verify = NULL;
 309     acb->finished = NULL;
 310     return acb;
 311 }
 312
 313 static void blkverify_aio_bh(void *opaque)
 314 {
 315     BlkverifyAIOCB *acb = opaque;
 316
 317     qemu_bh_delete(acb->bh);
 318     if (acb->buf) {
 319         qemu_iovec_destroy(&acb->raw_qiov);
 320         qemu_vfree(acb->buf);
 321     }
 322     acb->common.cb(acb->common.opaque, acb->ret);
 323     if (acb->finished) {
 324         *acb->finished = true;
 325     }
 326     qemu_aio_release(acb);
 327 }
 328
 329 static void blkverify_aio_cb(void *opaque, int ret)
 330 {
 331     BlkverifyAIOCB *acb = opaque;
 332
 333     switch (++acb->done) {
 334     case 1:
 335         acb->ret = ret;
 336         break;
 337
 338     case 2:
 339         if (acb->ret != ret) {
 340             blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);
 341         }
 342
 343         if (acb->verify) {
 344             acb->verify(acb);
 345         }
 346
 347         acb->bh = qemu_bh_new(blkverify_aio_bh, acb);
 348         qemu_bh_schedule(acb->bh);
 349         break;
 350     }
 351 }
 352
 353 static void blkverify_verify_readv(BlkverifyAIOCB *acb)
 354 {
 355     ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
 356     if (offset != -1) {
 357         blkverify_err(acb, "contents mismatch in sector %" PRId64,
 358                       acb->sector_num + (int64_t)(offset / BDRV_SECTOR_SIZE));
 359     }
 360 }
 361
 362 static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,
 363         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 364         BlockDriverCompletionFunc *cb, void *opaque)
 365 {
 366     BDRVBlkverifyState *s = bs->opaque;
 367     BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,
 368                                             nb_sectors, cb, opaque);
 369
 370     acb->verify = blkverify_verify_readv;
 371     acb->buf = qemu_blockalign(bs->file, qiov->size);
 372     qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);
 373     blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);
 374
 375     bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,
 376                    blkverify_aio_cb, acb);
 377     bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,
 378                    blkverify_aio_cb, acb);
 379     return &acb->common;
 380 }
 381
 382 static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,
 383         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 384         BlockDriverCompletionFunc *cb, void *opaque)
 385 {
 386     BDRVBlkverifyState *s = bs->opaque;
 387     BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,
 388                                             nb_sectors, cb, opaque);
 389
 390     bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,
 391                     blkverify_aio_cb, acb);
 392     bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,
 393                     blkverify_aio_cb, acb);
 394     return &acb->common;
 395 }
 396
 397 static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,
 398                                              BlockDriverCompletionFunc *cb,
 399                                              void *opaque)
 400 {
 401     BDRVBlkverifyState *s = bs->opaque;
 402
 403     /* Only flush test file, the raw file is not important */
 404     return bdrv_aio_flush(s->test_file, cb, opaque);
 405 }
 406
 407 static BlockDriver bdrv_blkverify = {
 408     .format_name            = "blkverify",
 409     .protocol_name          = "blkverify",
 410     .instance_size          = sizeof(BDRVBlkverifyState),
 411
 412     .bdrv_parse_filename    = blkverify_parse_filename,
 413     .bdrv_file_open         = blkverify_open,
 414     .bdrv_close             = blkverify_close,
 415     .bdrv_getlength         = blkverify_getlength,
 416
 417     .bdrv_aio_readv         = blkverify_aio_readv,
 418     .bdrv_aio_writev        = blkverify_aio_writev,
 419     .bdrv_aio_flush         = blkverify_aio_flush,
 420
 421     .bdrv_check_ext_snapshot = bdrv_check_ext_snapshot_forbidden,
 422 };
 423
 424 static void bdrv_blkverify_init(void)
 425 {
 426     bdrv_register(&bdrv_blkverify);
 427 }
 428
 429 block_init(bdrv_blkverify_init);