Re: [libvirt] [PATCH v5 4/6] block: Convert open calls to qemu_open
On 07/25/2012 03:22 PM, Eric Blake wrote:
On 07/23/2012 07:08 AM, Corey Bryant wrote:
> This patch converts all block layer open calls to qemu_open.
>
> Note that this adds the O_CLOEXEC flag to the changed open paths
> when the O_CLOEXEC macro is defined.
Is it actually adding O_CLOEXEC, or just the ability to use O_CLOEXEC?
It is adding O_CLOEXEC in qemu_open() on the open() call (as long as it
is defined).
Or is the actual change that the end result is that the fd now has
FD_CLOEXEC set unconditionally, whether by O_CLOEXEC (which the caller
need not pass) or by fcntl()?
The statement in the commit message isn't referring to anything dealing
with qemu_dup(). The statement is specifically talking about the open()
call in qemu_open(), and the point is to alert folks that old open()
calls are now being routed through qemu_open() and likely are using the
O_CLOEXEC flag, which is new behavior.
> +++ b/block/raw-posix.c
> @@ -572,8 +572,8 @@ static int raw_create(const char *filename, QEMUOptionParameter
*options)
> options++;
> }
>
> - fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
> - 0644);
> + fd = qemu_open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY,
> + 0644);
After all, I don't see O_CLOEXEC used here.
That's right. qemu_open() adds O_CLOEXEC on the open() call.
> if (fd < 0) {
> result = -errno;
> } else {
> @@ -846,7 +846,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename,
int flags)
> if ( bsdPath[ 0 ] != '\0' ) {
> strcat(bsdPath,"s0");
> /* some CDs don't have a partition 0 */
> - fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
> + fd = qemu_open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
Also, I still stand by my earlier claim that we don't need O_LARGEFILE
here (we should already be configuring for 64-bit off_t by default),
although cleaning that up is probably worth an independent commit.
I have a note to get rid of O_LARGEFILE as a separate follow-on patch.
> +++ b/block/vdi.c
> @@ -653,8 +653,9 @@ static int vdi_create(const char *filename, QEMUOptionParameter
*options)
> options++;
> }
>
> - fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
> - 0644);
> + fd = qemu_open(filename,
> + O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
> + 0644);
Another pointless O_LARGEFILE, and so forth.
Yep.
--
Regards,
Corey