diff options
| author | Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> | 2011-08-04 12:26:52 +0100 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2011-08-23 14:15:17 +0200 |
| commit | 92196b2f5664d5defa778b1b24df56e2239b5e93 (patch) | |
| tree | 944fe6b4fb403578fdb43073ce622ef0a34befc6 /qemu-config.c | |
| parent | c3993cdca39c252d65bbbcc234d8d242dc9bd693 (diff) | |
block: add cache=directsync parameter to -drive
This patch adds -drive cache=directsync for O_DIRECT | O_SYNC host file
I/O with no disk write cache presented to the guest.
This mode is useful when guests may not be sending flushes when
appropriate and therefore leave data at risk in case of power failure.
When cache=directsync is used, write operations are only completed to
the guest when data is safely on disk.
This new mode is like cache=writethrough but it bypasses the host page
cache.
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'qemu-config.c')
| -rw-r--r-- | qemu-config.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/qemu-config.c b/qemu-config.c index 1eb6b9a709..139e07768b 100644 --- a/qemu-config.c +++ b/qemu-config.c @@ -55,7 +55,8 @@ static QemuOptsList qemu_drive_opts = { },{ .name = "cache", .type = QEMU_OPT_STRING, - .help = "host cache usage (none, writeback, writethrough, unsafe)", + .help = "host cache usage (none, writeback, writethrough, " + "directsync, unsafe)", },{ .name = "aio", .type = QEMU_OPT_STRING, |