tests/test-flush-plugin.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #define NBDKIT_API_VERSION 2
  40
  41 #include <nbdkit-plugin.h>
  42
  43 /* level abuses our knowledge of internal nbdkit values:
  44  *  -1: force error during connect
  45  *   0: no flush, no FUA
  46  *   1: flush works, FUA is emulated
  47  *   2: flush works, FUA is native
  48  */
  49 static int level = -1;
  50
  51 static int
  52 flush_config (const char *key, const char *value)
  53 {
  54   if (strcmp (key, "level") == 0)
  55     return nbdkit_parse_int (key, value, &level);
  56   nbdkit_error ("unknown parameter '%s'", key);
  57   return -1;
  58 }
  59
  60 /* Implements both .can_flush and .can_fua */
  61 static int
  62 flush_level (void *handle)
  63 {
  64   return level;
  65 }
  66
  67 static void *
  68 flush_open (int readonly)
  69 {
  70   return NBDKIT_HANDLE_NOT_NEEDED;
  71 }
  72
  73 static int64_t
  74 flush_get_size (void *handle)
  75 {
  76   return 1024*1024;
  77 }
  78
  79 #define THREAD_MODEL NBDKIT_THREAD_MODEL_PARALLEL
  80
  81 static int
  82 flush_pread (void *handle, void *buf, uint32_t count, uint64_t offset,
  83              uint32_t flags)
  84 {
  85   memset (buf, 0, count);
  86   return 0;
  87 }
  88
  89 static int
  90 flush_pwrite (void *handle, const void *buf, uint32_t count, uint64_t offset,
  91               uint32_t flags)
  92 {
  93   if (flags & NBDKIT_FLAG_FUA)
  94     nbdkit_debug (" **handling native FUA");
  95   return 0;
  96 }
  97
  98 static int
  99 flush_flush (void *handle, uint32_t flags)
 100 {
 101   nbdkit_debug (" **handling flush");
 102   return 0;
 103 }
 104
 105 static struct nbdkit_plugin plugin = {
 106   .name              = "flush",
 107   .version           = PACKAGE_VERSION,
 108   .config            = flush_config,
 109   .magic_config_key  = "level",
 110   .open              = flush_open,
 111   .get_size          = flush_get_size,
 112   .pread             = flush_pread,
 113   .pwrite            = flush_pwrite,
 114   .can_flush         = flush_level,
 115   .can_fua           = flush_level,
 116   .flush             = flush_flush,
 117 };
 118
 119 NBDKIT_REGISTER_PLUGIN (plugin)