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