On 17.05.2016 09:35, Fam Zheng wrote:
> They are wrappers of POSIX fcntl "file private locking".
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> include/qemu/osdep.h | 2 ++
> util/osdep.c | 31 +++++++++++++++++++++++++++++++
> 2 files changed, 33 insertions(+)
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 1e3221c..81913a7 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -265,6 +265,8 @@ 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 d56d071..9e5d7fa 100644
> --- a/util/osdep.c
> +++ b/util/osdep.c
> @@ -236,6 +236,37 @@ int qemu_close(int fd)
> return close(fd);
> }
>
> +static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
> +{
> +#ifdef F_OFD_SETLK
> + struct flock fl = (struct flock) {
The (struct flock) can be omitted here (since this is an
initialization), but that's up to you.
> + .l_whence = SEEK_SET,
One space too many?
> + /* Locking byte 1 avoids interfereing with virtlockd. */
*interfering or *interference
But apart from that: This comment seems completely misplaced here. I
guess it's supposed to be in raw-posix.c instead (or just wherever
you're calling qemu_{un,}lock_fd()).
> + .l_start = start,
> + .l_len = len,
> + .l_type = fl_type,
> + };
> + if (fcntl(fd, F_OFD_SETLK, &fl) == -1) {
> + return -errno;
> + } else {
> + return 0;
> + }
> +#else
> + return -ENOTSUP;
> +#endif
> +}
> +
> +int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
> +{
> +
Superfluous empty line.
Max
> + return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
> +}
> +
> +int qemu_unlock_fd(int fd, int64_t start, int64_t len)
> +{
> + return qemu_lock_fcntl(fd, start, len, F_UNLCK);
> +}
> +
> /*
> * A variant of write(2) which handles partial write.
> *
>
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