debian/patches/rbd-enable-cacheoption.patch

   1 Signed-off-by: Josh Durgin <address@hidden>
   2 ---
   3  block/rbd.c |   19 +++++++++++++++++++
   4  1 files changed, 19 insertions(+), 0 deletions(-)
   5
   6 diff --git a/block/rbd.c b/block/rbd.c
   7 index 1280d66..eebc334 100644
   8 --- a/block/rbd.c
   9 +++ b/block/rbd.c
  10 @@ -476,6 +476,25 @@ static int qemu_rbd_open(BlockDriverState *bs, const char *filename, int flags)
  11          s->snap = g_strdup(snap_buf);
  12      }
  13
  14 +    /*
  15 +     * Fallback to more conservative semantics if setting cache
  16 +     * options fails. Ignore errors from setting rbd_cache because the
  17 +     * only possible error is that the option does not exist, and
  18 +     * librbd defaults to no caching. If write through caching cannot
  19 +     * be set up, fall back to no caching.
  20 +     */
  21 +    if (flags & BDRV_O_NOCACHE) {
  22 +        rados_conf_set(s->cluster, "rbd_cache", "false");
  23 +    } else {
  24 +        rados_conf_set(s->cluster, "rbd_cache", "true");
  25 +        if (!(flags & BDRV_O_CACHE_WB)) {
  26 +            r = rados_conf_set(s->cluster, "rbd_cache_max_dirty", "0");
  27 +            if (r < 0) {
  28 +                rados_conf_set(s->cluster, "rbd_cache", "false");
  29 +            }
  30 +        }
  31 +    }
  32 +
  33      if (strstr(conf, "conf=") == NULL) {
  34          /* try default location, but ignore failure */
  35          rados_conf_read_file(s->cluster, NULL);
  36 --
  37 1.7.5.4