diff options
| -rw-r--r-- | block/rbd.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/block/rbd.c b/block/rbd.c index 1280d66d3c..eebc334462 100644 --- a/block/rbd.c +++ b/block/rbd.c @@ -476,6 +476,25 @@ static int qemu_rbd_open(BlockDriverState *bs, const char *filename, int flags) s->snap = g_strdup(snap_buf); } + /* + * Fallback to more conservative semantics if setting cache + * options fails. Ignore errors from setting rbd_cache because the + * only possible error is that the option does not exist, and + * librbd defaults to no caching. If write through caching cannot + * be set up, fall back to no caching. + */ + if (flags & BDRV_O_NOCACHE) { + rados_conf_set(s->cluster, "rbd_cache", "false"); + } else { + rados_conf_set(s->cluster, "rbd_cache", "true"); + if (!(flags & BDRV_O_CACHE_WB)) { + r = rados_conf_set(s->cluster, "rbd_cache_max_dirty", "0"); + if (r < 0) { + rados_conf_set(s->cluster, "rbd_cache", "false"); + } + } + } + if (strstr(conf, "conf=") == NULL) { /* try default location, but ignore failure */ rados_conf_read_file(s->cluster, NULL); |