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Re: [Qemu-block] [PATCH v6 05/22] osdep: Add qemu_lock_fd and qemu_unloc
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-block] [PATCH v6 05/22] osdep: Add qemu_lock_fd and qemu_unlock_fd |
Date: |
Fri, 17 Jun 2016 14:12:13 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 03.06.2016 um 10:48 hat Fam Zheng geschrieben:
> They are wrappers of POSIX fcntl "file private locking".
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> include/qemu/osdep.h | 2 ++
> util/osdep.c | 29 +++++++++++++++++++++++++++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 6937694..749214a 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -280,6 +280,8 @@ int qemu_madvise(void *addr, size_t len, int advice);
>
> int qemu_open(const char *name, int flags, ...);
> int qemu_close(int fd);
> +int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
> +int qemu_unlock_fd(int fd, int64_t start, int64_t len);
>
> #if defined(__HAIKU__) && defined(__i386__)
> #define FMT_pid "%ld"
> diff --git a/util/osdep.c b/util/osdep.c
> index 9a7a439..085ed52 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -137,6 +137,35 @@ static int qemu_parse_fdset(const char *param)
> {
> return qemu_parse_fd(param);
> }
> +
> +static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
> +{
> +#ifdef F_OFD_SETLK
> + int ret;
> + struct flock fl = {
> + .l_whence = SEEK_SET,
> + .l_start = start,
> + .l_len = len,
> + .l_type = fl_type,
> + };
> + do {
> + ret = fcntl(fd, F_OFD_SETLK, &fl);
> + } while (ret == -1 && errno == EINTR);
> + return ret == -1 ? -errno : 0;
> +#else
> + return -ENOTSUP;
> +#endif
> +}
This will return -ENOTSUP in the case that the function wasn't available
at build time, but -EINVAL if it was available at build time but the
kernel doesn't support it at runtime. Should we unify this?
Kevin
- [Qemu-block] [PATCH v6 04/22] block: Introduce image file locking, (continued)
[Qemu-block] [PATCH v6 03/22] blockdev: Add and parse "lock-mode" option for image locking, Fam Zheng, 2016/06/03
[Qemu-block] [PATCH v6 05/22] osdep: Add qemu_lock_fd and qemu_unlock_fd, Fam Zheng, 2016/06/03
- Re: [Qemu-block] [PATCH v6 05/22] osdep: Add qemu_lock_fd and qemu_unlock_fd,
Kevin Wolf <=
[Qemu-block] [PATCH v6 07/22] raw-posix: Use qemu_dup, Fam Zheng, 2016/06/03
[Qemu-block] [PATCH v6 06/22] osdep: Introduce qemu_dup, Fam Zheng, 2016/06/03
[Qemu-block] [PATCH v6 09/22] qemu-io: Add "-L" option for BDRV_O_NO_LOCK, Fam Zheng, 2016/06/03
[Qemu-block] [PATCH v6 08/22] raw-posix: Add image locking support, Fam Zheng, 2016/06/03