diff options
| author | Paolo Bonzini <pbonzini@redhat.com> | 2012-07-18 14:57:15 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2012-07-24 09:31:53 +0200 |
| commit | 39a5235cd7f367cce7be7b3f4d258452452e38e3 (patch) | |
| tree | f0d618f82745259de3144ec4bdcca3f336a453ca /qemu-nbd.c | |
| parent | b033cd864042646dd3e17a23c7850c413bc360f4 (diff) | |
qemu-nbd: add --cache and --aio options
Add two options to tune the I/O implementation of qemu-nbd, matching
the possibilities given by the QEMU -drive option.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'qemu-nbd.c')
| -rw-r--r-- | qemu-nbd.c | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/qemu-nbd.c b/qemu-nbd.c index 1c32290a8e..1c1cf6a463 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -33,7 +33,9 @@ #include <libgen.h> #include <pthread.h> -#define SOCKET_PATH "/var/lock/qemu-nbd-%s" +#define SOCKET_PATH "/var/lock/qemu-nbd-%s" +#define QEMU_NBD_OPT_CACHE 1 +#define QEMU_NBD_OPT_AIO 2 static NBDExport *exp; static int verbose; @@ -77,6 +79,10 @@ static void usage(const char *name) " -r, --read-only export read-only\n" " -s, --snapshot use snapshot file\n" " -n, --nocache disable host cache\n" +" --cache=MODE set cache mode (none, writeback, ...)\n" +#ifdef CONFIG_LINUX_AIO +" --aio=MODE set AIO mode (native or threads)\n" +#endif "\n" "Report bugs to <qemu-devel@nongnu.org>\n" , name, NBD_DEFAULT_PORT, "DEVICE"); @@ -306,6 +312,10 @@ int main(int argc, char **argv) { "disconnect", 0, NULL, 'd' }, { "snapshot", 0, NULL, 's' }, { "nocache", 0, NULL, 'n' }, + { "cache", 1, NULL, QEMU_NBD_OPT_CACHE }, +#ifdef CONFIG_LINUX_AIO + { "aio", 1, NULL, QEMU_NBD_OPT_AIO }, +#endif { "shared", 1, NULL, 'e' }, { "persistent", 0, NULL, 't' }, { "verbose", 0, NULL, 'v' }, @@ -320,6 +330,10 @@ int main(int argc, char **argv) int ret; int fd; int persistent = 0; + bool seen_cache = false; +#ifdef CONFIG_LINUX_AIO + bool seen_aio = false; +#endif pthread_t client_thread; /* The client thread uses SIGTERM to interrupt the server. A signal @@ -336,8 +350,32 @@ int main(int argc, char **argv) flags |= BDRV_O_SNAPSHOT; break; case 'n': - flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; + optarg = (char *) "none"; + /* fallthrough */ + case QEMU_NBD_OPT_CACHE: + if (seen_cache) { + errx(EXIT_FAILURE, "-n and --cache can only be specified once"); + } + seen_cache = true; + if (bdrv_parse_cache_flags(optarg, &flags) == -1) { + errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg); + } break; +#ifdef CONFIG_LINUX_AIO + case QEMU_NBD_OPT_AIO: + if (seen_aio) { + errx(EXIT_FAILURE, "--aio can only be specified once"); + } + seen_aio = true; + if (!strcmp(optarg, "native")) { + flags |= BDRV_O_NATIVE_AIO; + } else if (!strcmp(optarg, "threads")) { + /* this is the default */ + } else { + errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg); + } + break; +#endif case 'b': bindto = optarg; break; |