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         error_propagate(errp, local_err);
 132         ret = -EINVAL;
 133         goto fail;
 134     }
 135
 136     /* Parse the raw image filename */
 137     raw = qemu_opt_get(opts, "x-raw");
 138     if (raw == NULL) {
 139         error_setg(errp, "Could not retrieve raw image filename");
 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         error_propagate(errp, local_err);
 147         goto fail;
 148     }
 149
 150     /* Open the test file */
 151     filename = qemu_opt_get(opts, "x-image");
 152     if (filename == NULL) {
 153         error_setg(errp, "Could not retrieve test image filename");
 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         error_propagate(errp, local_err);
 162         bdrv_unref(s->test_file);
 163         s->test_file = NULL;
 164         goto fail;
 165     }
 166
 167     ret = 0;
 168 fail:
 169     return ret;
 170 }
 171
 172 static void blkverify_close(BlockDriverState *bs)
 173 {
 174     BDRVBlkverifyState *s = bs->opaque;
 175
 176     bdrv_unref(s->test_file);
 177     s->test_file = NULL;
 178 }
 179
 180 static int64_t blkverify_getlength(BlockDriverState *bs)
 181 {
 182     BDRVBlkverifyState *s = bs->opaque;
 183
 184     return bdrv_getlength(s->test_file);
 185 }
 186
 187 /**
 188  * Check that I/O vector contents are identical
 189  *
 190  * @a:          I/O vector
 191  * @b:          I/O vector
 192  * @ret:        Offset to first mismatching byte or -1 if match
 193  */
 194 static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
 195 {
 196     int i;
 197     ssize_t offset = 0;
 198
 199     assert(a->niov == b->niov);
 200     for (i = 0; i < a->niov; i++) {
 201         size_t len = 0;
 202         uint8_t *p = (uint8_t *)a->iov[i].iov_base;
 203         uint8_t *q = (uint8_t *)b->iov[i].iov_base;
 204
 205         assert(a->iov[i].iov_len == b->iov[i].iov_len);
 206         while (len < a->iov[i].iov_len && *p++ == *q++) {
 207             len++;
 208         }
 209
 210         offset += len;
 211
 212         if (len != a->iov[i].iov_len) {
 213             return offset;
 214         }
 215     }
 216     return -1;
 217 }
 218
 219 typedef struct {
 220     int src_index;
 221     struct iovec *src_iov;
 222     void *dest_base;
 223 } IOVectorSortElem;
 224
 225 static int sortelem_cmp_src_base(const void *a, const void *b)
 226 {
 227     const IOVectorSortElem *elem_a = a;
 228     const IOVectorSortElem *elem_b = b;
 229
 230     /* Don't overflow */
 231     if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
 232         return -1;
 233     } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
 234         return 1;
 235     } else {
 236         return 0;
 237     }
 238 }
 239
 240 static int sortelem_cmp_src_index(const void *a, const void *b)
 241 {
 242     const IOVectorSortElem *elem_a = a;
 243     const IOVectorSortElem *elem_b = b;
 244
 245     return elem_a->src_index - elem_b->src_index;
 246 }
 247
 248 /**
 249  * Copy contents of I/O vector
 250  *
 251  * The relative relationships of overlapping iovecs are preserved.  This is
 252  * necessary to ensure identical semantics in the cloned I/O vector.
 253  */
 254 static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,
 255                                   void *buf)
 256 {
 257     IOVectorSortElem sortelems[src->niov];
 258     void *last_end;
 259     int i;
 260
 261     /* Sort by source iovecs by base address */
 262     for (i = 0; i < src->niov; i++) {
 263         sortelems[i].src_index = i;
 264         sortelems[i].src_iov = &src->iov[i];
 265     }
 266     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
 267
 268     /* Allocate buffer space taking into account overlapping iovecs */
 269     last_end = NULL;
 270     for (i = 0; i < src->niov; i++) {
 271         struct iovec *cur = sortelems[i].src_iov;
 272         ptrdiff_t rewind = 0;
 273
 274         /* Detect overlap */
 275         if (last_end && last_end > cur->iov_base) {
 276             rewind = last_end - cur->iov_base;
 277         }
 278
 279         sortelems[i].dest_base = buf - rewind;
 280         buf += cur->iov_len - MIN(rewind, cur->iov_len);
 281         last_end = MAX(cur->iov_base + cur->iov_len, last_end);
 282     }
 283
 284     /* Sort by source iovec index and build destination iovec */
 285     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
 286     for (i = 0; i < src->niov; i++) {
 287         qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
 288     }
 289 }
 290
 291 static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
 292                                          int64_t sector_num, QEMUIOVector *qiov,
 293                                          int nb_sectors,
 294                                          BlockDriverCompletionFunc *cb,
 295                                          void *opaque)
 296 {
 297     BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aiocb_info, bs, cb, opaque);
 298
 299     acb->bh = NULL;
 300     acb->is_write = is_write;
 301     acb->sector_num = sector_num;
 302     acb->nb_sectors = nb_sectors;
 303     acb->ret = -EINPROGRESS;
 304     acb->done = 0;
 305     acb->qiov = qiov;
 306     acb->buf = NULL;
 307     acb->verify = NULL;
 308     acb->finished = NULL;
 309     return acb;
 310 }
 311
 312 static void blkverify_aio_bh(void *opaque)
 313 {
 314     BlkverifyAIOCB *acb = opaque;
 315
 316     qemu_bh_delete(acb->bh);
 317     if (acb->buf) {
 318         qemu_iovec_destroy(&acb->raw_qiov);
 319         qemu_vfree(acb->buf);
 320     }
 321     acb->common.cb(acb->common.opaque, acb->ret);
 322     if (acb->finished) {
 323         *acb->finished = true;
 324     }
 325     qemu_aio_release(acb);
 326 }
 327
 328 static void blkverify_aio_cb(void *opaque, int ret)
 329 {
 330     BlkverifyAIOCB *acb = opaque;
 331
 332     switch (++acb->done) {
 333     case 1:
 334         acb->ret = ret;
 335         break;
 336
 337     case 2:
 338         if (acb->ret != ret) {
 339             blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);
 340         }
 341
 342         if (acb->verify) {
 343             acb->verify(acb);
 344         }
 345
 346         acb->bh = qemu_bh_new(blkverify_aio_bh, acb);
 347         qemu_bh_schedule(acb->bh);
 348         break;
 349     }
 350 }
 351
 352 static void blkverify_verify_readv(BlkverifyAIOCB *acb)
 353 {
 354     ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
 355     if (offset != -1) {
 356         blkverify_err(acb, "contents mismatch in sector %" PRId64,
 357                       acb->sector_num + (int64_t)(offset / BDRV_SECTOR_SIZE));
 358     }
 359 }
 360
 361 static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,
 362         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 363         BlockDriverCompletionFunc *cb, void *opaque)
 364 {
 365     BDRVBlkverifyState *s = bs->opaque;
 366     BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,
 367                                             nb_sectors, cb, opaque);
 368
 369     acb->verify = blkverify_verify_readv;
 370     acb->buf = qemu_blockalign(bs->file, qiov->size);
 371     qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);
 372     blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);
 373
 374     bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,
 375                    blkverify_aio_cb, acb);
 376     bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,
 377                    blkverify_aio_cb, acb);
 378     return &acb->common;
 379 }
 380
 381 static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,
 382         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 383         BlockDriverCompletionFunc *cb, void *opaque)
 384 {
 385     BDRVBlkverifyState *s = bs->opaque;
 386     BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,
 387                                             nb_sectors, cb, opaque);
 388
 389     bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,
 390                     blkverify_aio_cb, acb);
 391     bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,
 392                     blkverify_aio_cb, acb);
 393     return &acb->common;
 394 }
 395
 396 static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,
 397                                              BlockDriverCompletionFunc *cb,
 398                                              void *opaque)
 399 {
 400     BDRVBlkverifyState *s = bs->opaque;
 401
 402     /* Only flush test file, the raw file is not important */
 403     return bdrv_aio_flush(s->test_file, cb, opaque);
 404 }
 405
 406 static BlockDriver bdrv_blkverify = {
 407     .format_name            = "blkverify",
 408     .protocol_name          = "blkverify",
 409     .instance_size          = sizeof(BDRVBlkverifyState),
 410
 411     .bdrv_parse_filename    = blkverify_parse_filename,
 412     .bdrv_file_open         = blkverify_open,
 413     .bdrv_close             = blkverify_close,
 414     .bdrv_getlength         = blkverify_getlength,
 415
 416     .bdrv_aio_readv         = blkverify_aio_readv,
 417     .bdrv_aio_writev        = blkverify_aio_writev,
 418     .bdrv_aio_flush         = blkverify_aio_flush,
 419
 420     .bdrv_check_ext_snapshot = bdrv_check_ext_snapshot_forbidden,
 421 };
 422
 423 static void bdrv_blkverify_init(void)
 424 {
 425     bdrv_register(&bdrv_blkverify);
 426 }
 427
 428 block_init(bdrv_blkverify_init);