On Tue, Mar 02, 2010 at 04:26:59PM +0100, Jiri Denemark wrote:
> Instead of opening storage file with O_DSYNC, make sure data are written
> to a disk only before we claim allocation has finished.
>
> Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
> ---
> src/storage/storage_backend.c | 9 ++++++++-
> 1 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
> index 849f01b..4cc2f93 100644
> --- a/src/storage/storage_backend.c
> +++ b/src/storage/storage_backend.c
> @@ -332,6 +332,13 @@ static int createRawFileOpHook(int fd, void *data) {
> goto cleanup;
> }
> }
> +
> + if (fsync(fd) < 0) {
> + ret = errno;
> + virReportSystemError(errno, _("cannot sync data to file '%s'"),
> + hdata->vol->target.path);
> + goto cleanup;
> + }
> }
>
> cleanup:
> @@ -357,7 +364,7 @@ virStorageBackendCreateRaw(virConnectPtr conn ATTRIBUTE_UNUSED,
> }
>
> if ((createstat = virFileOperation(vol->target.path,
> - O_RDWR | O_CREAT | O_EXCL | O_DSYNC,
> + O_RDWR | O_CREAT | O_EXCL,
> vol->target.perms.mode,
> vol->target.perms.uid, vol->target.perms.gid,
> createRawFileOpHook, &hdata,
I would tend to prefer this patch on the basis that I would prefer a
smaller change to the code at this point before the release. But the
O_DSYNC was added after finding that cache effects could just break the
qemu startup timeout in the test environment. I'm not 100% sure fsync()
will have the same behaviour overall, it should but theory and practice
may diverge :-)
So I'm tempted to go with this patch but we should validate it on testing
before the end of the week.
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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