[libvirt] [Qemu-devel] [PATCH v4 7/7] osdep: Enable qemu_open to dup pre-opened fd

[Kevin Wolf]

Am 25.06.2012 16:34, schrieb Eric Blake:
>> Also, I noticed in the fnctl man page that F_SETFL:  "On Linux this
>> command can change only the O_APPEND, O_ASYNC, O_DIRECT, O_NOATIME, and
>> O_NONBLOCK flags."  So I'll only set/unset these flags.
> 
> O_NDELAY is the obsolete spelling of O_NONBLOCK; which means the only
> other flags in your list not supported by Linux are O_LARGEFILE (which I
> said was pointless), O_NOCTTY (which only has an impact at open() and
> not later on, so it is not worth worrying about), and O_SYNC (so for
> that one, you should error out if not set correctly, as the difference
> between O_SYNC on vs. off is significant).

As far as I know, newer kernels can change O_SYNC with fcntl, so it's
probably worth trying, but you'd have to check if it has really been set.

Kevin