Daniel P. Berrangé <berra...@redhat.com> writes:
> Currently we suggest that a filesystem may not support O_DIRECT after
> seeing an EINVAL. Other things can cause EINVAL though, so it is better
> to do an explicit check, and then report a definitive error message.
>
> Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
> ---
> util/osdep.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/util/osdep.c b/util/osdep.c
> index 4829c07ff6..e2b7507ee2 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -332,9 +332,11 @@ int qemu_open(const char *name, int flags, ...)
> }
>
> #ifdef O_CLOEXEC
> - ret = open(name, flags | O_CLOEXEC, mode);
> -#else
> + flags |= O_CLOEXEC;
> +#endif
> ret = open(name, flags, mode);
> +
> +#ifndef O_CLOEXEC
> if (ret >= 0) {
> qemu_set_cloexec(ret);
> }
I'd prefer something like
#ifdef O_CLOEXEC
flags |= O_CLOEXEC;
ret = open(name, flags, mode);
#else
ret = open(name, flags, mode);
if (ret >= 0) {
qemu_set_cloexec(ret);
}
#endif
Continues to duplicate open(), but spares me the effort to fuse two
#ifdef sections in my head to understand what is being done in each
case.
> @@ -342,8 +344,13 @@ int qemu_open(const char *name, int flags, ...)
>
> #ifdef O_DIRECT
> if (ret == -1 && errno == EINVAL && (flags & O_DIRECT)) {
> - error_report("file system may not support O_DIRECT");
> - errno = EINVAL; /* in case it was clobbered */
> + int newflags = flags & ~O_DIRECT;
> + ret = open(name, newflags, mode);
I'd prefer the more concise
ret = open(name, flags & ~O_DIRECT, mode);
> + if (ret != -1) {
> + close(ret);
> + error_report("file system does not support O_DIRECT");
> + errno = EINVAL;
> + }
> }
> #endif /* O_DIRECT */
The function now reports to stderr in just one of many failure modes.
That's wrong. Looks like the next patch fixes this defect. I'd swap
the two.
