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_socket.h" /* for EINPROGRESS on Windows */
  12 #include "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 AIOPool blkverify_aio_pool = {
  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 int blkverify_open(BlockDriverState *bs, const char *filename, int flags)
  73 {
  74     BDRVBlkverifyState *s = bs->opaque;
  75     int ret;
  76     char *raw, *c;
  77
  78     /* Parse the blkverify: prefix */
  79     if (strncmp(filename, "blkverify:", strlen("blkverify:"))) {
  80         return -EINVAL;
  81     }
  82     filename += strlen("blkverify:");
  83
  84     /* Parse the raw image filename */
  85     c = strchr(filename, ':');
  86     if (c == NULL) {
  87         return -EINVAL;
  88     }
  89
  90     raw = strdup(filename);
  91     raw[c - filename] = '\0';
  92     ret = bdrv_file_open(&bs->file, raw, flags);
  93     free(raw);
  94     if (ret < 0) {
  95         return ret;
  96     }
  97     filename = c + 1;
  98
  99     /* Open the test file */
 100     s->test_file = bdrv_new("");
 101     ret = bdrv_open(s->test_file, filename, flags, NULL);
 102     if (ret < 0) {
 103         bdrv_delete(s->test_file);
 104         s->test_file = NULL;
 105         return ret;
 106     }
 107
 108     return 0;
 109 }
 110
 111 static void blkverify_close(BlockDriverState *bs)
 112 {
 113     BDRVBlkverifyState *s = bs->opaque;
 114
 115     bdrv_delete(s->test_file);
 116     s->test_file = NULL;
 117 }
 118
 119 static int blkverify_flush(BlockDriverState *bs)
 120 {
 121     BDRVBlkverifyState *s = bs->opaque;
 122
 123     /* Only flush test file, the raw file is not important */
 124     return bdrv_flush(s->test_file);
 125 }
 126
 127 static int64_t blkverify_getlength(BlockDriverState *bs)
 128 {
 129     BDRVBlkverifyState *s = bs->opaque;
 130
 131     return bdrv_getlength(s->test_file);
 132 }
 133
 134 /**
 135  * Check that I/O vector contents are identical
 136  *
 137  * @a:          I/O vector
 138  * @b:          I/O vector
 139  * @ret:        Offset to first mismatching byte or -1 if match
 140  */
 141 static ssize_t blkverify_iovec_compare(QEMUIOVector *a, QEMUIOVector *b)
 142 {
 143     int i;
 144     ssize_t offset = 0;
 145
 146     assert(a->niov == b->niov);
 147     for (i = 0; i < a->niov; i++) {
 148         size_t len = 0;
 149         uint8_t *p = (uint8_t *)a->iov[i].iov_base;
 150         uint8_t *q = (uint8_t *)b->iov[i].iov_base;
 151
 152         assert(a->iov[i].iov_len == b->iov[i].iov_len);
 153         while (len < a->iov[i].iov_len && *p++ == *q++) {
 154             len++;
 155         }
 156
 157         offset += len;
 158
 159         if (len != a->iov[i].iov_len) {
 160             return offset;
 161         }
 162     }
 163     return -1;
 164 }
 165
 166 typedef struct {
 167     int src_index;
 168     struct iovec *src_iov;
 169     void *dest_base;
 170 } IOVectorSortElem;
 171
 172 static int sortelem_cmp_src_base(const void *a, const void *b)
 173 {
 174     const IOVectorSortElem *elem_a = a;
 175     const IOVectorSortElem *elem_b = b;
 176
 177     /* Don't overflow */
 178     if (elem_a->src_iov->iov_base < elem_b->src_iov->iov_base) {
 179         return -1;
 180     } else if (elem_a->src_iov->iov_base > elem_b->src_iov->iov_base) {
 181         return 1;
 182     } else {
 183         return 0;
 184     }
 185 }
 186
 187 static int sortelem_cmp_src_index(const void *a, const void *b)
 188 {
 189     const IOVectorSortElem *elem_a = a;
 190     const IOVectorSortElem *elem_b = b;
 191
 192     return elem_a->src_index - elem_b->src_index;
 193 }
 194
 195 /**
 196  * Copy contents of I/O vector
 197  *
 198  * The relative relationships of overlapping iovecs are preserved.  This is
 199  * necessary to ensure identical semantics in the cloned I/O vector.
 200  */
 201 static void blkverify_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src,
 202                                   void *buf)
 203 {
 204     IOVectorSortElem sortelems[src->niov];
 205     void *last_end;
 206     int i;
 207
 208     /* Sort by source iovecs by base address */
 209     for (i = 0; i < src->niov; i++) {
 210         sortelems[i].src_index = i;
 211         sortelems[i].src_iov = &src->iov[i];
 212     }
 213     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_base);
 214
 215     /* Allocate buffer space taking into account overlapping iovecs */
 216     last_end = NULL;
 217     for (i = 0; i < src->niov; i++) {
 218         struct iovec *cur = sortelems[i].src_iov;
 219         ptrdiff_t rewind = 0;
 220
 221         /* Detect overlap */
 222         if (last_end && last_end > cur->iov_base) {
 223             rewind = last_end - cur->iov_base;
 224         }
 225
 226         sortelems[i].dest_base = buf - rewind;
 227         buf += cur->iov_len - MIN(rewind, cur->iov_len);
 228         last_end = MAX(cur->iov_base + cur->iov_len, last_end);
 229     }
 230
 231     /* Sort by source iovec index and build destination iovec */
 232     qsort(sortelems, src->niov, sizeof(sortelems[0]), sortelem_cmp_src_index);
 233     for (i = 0; i < src->niov; i++) {
 234         qemu_iovec_add(dest, sortelems[i].dest_base, src->iov[i].iov_len);
 235     }
 236 }
 237
 238 static BlkverifyAIOCB *blkverify_aio_get(BlockDriverState *bs, bool is_write,
 239                                          int64_t sector_num, QEMUIOVector *qiov,
 240                                          int nb_sectors,
 241                                          BlockDriverCompletionFunc *cb,
 242                                          void *opaque)
 243 {
 244     BlkverifyAIOCB *acb = qemu_aio_get(&blkverify_aio_pool, bs, cb, opaque);
 245
 246     acb->bh = NULL;
 247     acb->is_write = is_write;
 248     acb->sector_num = sector_num;
 249     acb->nb_sectors = nb_sectors;
 250     acb->ret = -EINPROGRESS;
 251     acb->done = 0;
 252     acb->qiov = qiov;
 253     acb->buf = NULL;
 254     acb->verify = NULL;
 255     acb->finished = NULL;
 256     return acb;
 257 }
 258
 259 static void blkverify_aio_bh(void *opaque)
 260 {
 261     BlkverifyAIOCB *acb = opaque;
 262
 263     qemu_bh_delete(acb->bh);
 264     if (acb->buf) {
 265         qemu_iovec_destroy(&acb->raw_qiov);
 266         qemu_vfree(acb->buf);
 267     }
 268     acb->common.cb(acb->common.opaque, acb->ret);
 269     if (acb->finished) {
 270         *acb->finished = true;
 271     }
 272     qemu_aio_release(acb);
 273 }
 274
 275 static void blkverify_aio_cb(void *opaque, int ret)
 276 {
 277     BlkverifyAIOCB *acb = opaque;
 278
 279     switch (++acb->done) {
 280     case 1:
 281         acb->ret = ret;
 282         break;
 283
 284     case 2:
 285         if (acb->ret != ret) {
 286             blkverify_err(acb, "return value mismatch %d != %d", acb->ret, ret);
 287         }
 288
 289         if (acb->verify) {
 290             acb->verify(acb);
 291         }
 292
 293         acb->bh = qemu_bh_new(blkverify_aio_bh, acb);
 294         qemu_bh_schedule(acb->bh);
 295         break;
 296     }
 297 }
 298
 299 static void blkverify_verify_readv(BlkverifyAIOCB *acb)
 300 {
 301     ssize_t offset = blkverify_iovec_compare(acb->qiov, &acb->raw_qiov);
 302     if (offset != -1) {
 303         blkverify_err(acb, "contents mismatch in sector %" PRId64,
 304                       acb->sector_num + (int64_t)(offset / BDRV_SECTOR_SIZE));
 305     }
 306 }
 307
 308 static BlockDriverAIOCB *blkverify_aio_readv(BlockDriverState *bs,
 309         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 310         BlockDriverCompletionFunc *cb, void *opaque)
 311 {
 312     BDRVBlkverifyState *s = bs->opaque;
 313     BlkverifyAIOCB *acb = blkverify_aio_get(bs, false, sector_num, qiov,
 314                                             nb_sectors, cb, opaque);
 315
 316     acb->verify = blkverify_verify_readv;
 317     acb->buf = qemu_blockalign(bs->file, qiov->size);
 318     qemu_iovec_init(&acb->raw_qiov, acb->qiov->niov);
 319     blkverify_iovec_clone(&acb->raw_qiov, qiov, acb->buf);
 320
 321     if (!bdrv_aio_readv(s->test_file, sector_num, qiov, nb_sectors,
 322                         blkverify_aio_cb, acb)) {
 323         blkverify_aio_cb(acb, -EIO);
 324     }
 325     if (!bdrv_aio_readv(bs->file, sector_num, &acb->raw_qiov, nb_sectors,
 326                         blkverify_aio_cb, acb)) {
 327         blkverify_aio_cb(acb, -EIO);
 328     }
 329     return &acb->common;
 330 }
 331
 332 static BlockDriverAIOCB *blkverify_aio_writev(BlockDriverState *bs,
 333         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 334         BlockDriverCompletionFunc *cb, void *opaque)
 335 {
 336     BDRVBlkverifyState *s = bs->opaque;
 337     BlkverifyAIOCB *acb = blkverify_aio_get(bs, true, sector_num, qiov,
 338                                             nb_sectors, cb, opaque);
 339
 340     if (!bdrv_aio_writev(s->test_file, sector_num, qiov, nb_sectors,
 341                          blkverify_aio_cb, acb)) {
 342         blkverify_aio_cb(acb, -EIO);
 343     }
 344     if (!bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors,
 345                          blkverify_aio_cb, acb)) {
 346         blkverify_aio_cb(acb, -EIO);
 347     }
 348     return &acb->common;
 349 }
 350
 351 static BlockDriverAIOCB *blkverify_aio_flush(BlockDriverState *bs,
 352                                              BlockDriverCompletionFunc *cb,
 353                                              void *opaque)
 354 {
 355     BDRVBlkverifyState *s = bs->opaque;
 356
 357     /* Only flush test file, the raw file is not important */
 358     return bdrv_aio_flush(s->test_file, cb, opaque);
 359 }
 360
 361 static BlockDriver bdrv_blkverify = {
 362     .format_name        = "blkverify",
 363     .protocol_name      = "blkverify",
 364
 365     .instance_size      = sizeof(BDRVBlkverifyState),
 366
 367     .bdrv_getlength     = blkverify_getlength,
 368
 369     .bdrv_file_open     = blkverify_open,
 370     .bdrv_close         = blkverify_close,
 371     .bdrv_flush         = blkverify_flush,
 372
 373     .bdrv_aio_readv     = blkverify_aio_readv,
 374     .bdrv_aio_writev    = blkverify_aio_writev,
 375     .bdrv_aio_flush     = blkverify_aio_flush,
 376 };
 377
 378 static void bdrv_blkverify_init(void)
 379 {
 380     bdrv_register(&bdrv_blkverify);
 381 }
 382
 383 block_init(bdrv_blkverify_init);