On Sat, Nov 9, 2013 at 3:59 PM, Jeff Liu <jeff.liu@xxxxxxxxxx> wrote:
Hi Jeff Liu,
Thanks for your reply ;-)
> Mount your realtime device at first:
> mount -o rtdev=/dev/sda3 /dev/sda4 /mount_point
>
> Then you need to mark the attribute bit set with XFS_XFLAG_REALTIME via xfsctl(3)
> after file creation before writing any data to the file, hence your demo code
> would looks like:
>
> struct fsxattr attr;
>
> attr.fsx_xflags |= XFS_XFLAG_REALTIME;
> xfs_ret = xfsctl(target_file_path, fd, XFS_IOC_FSSETXATTR, &attr);
> ...
Yeah, it's right. I have mounted as you said and changed my codes as follows.
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <xfs/xfs.h>
#include <xfs/xfs_fs.h>
#define F_PATH "./rtxfs.txt"
#define EXTSIZE (0x00001000U)
int main(int argc, char **argv) {
int fd;
int ret = 0;
struct fsxattr fsxattr;
fd = open(F_PATH, O_RDWR|O_CREAT, 0666);
if (fd < 0) {
fprintf(stderr, "open error!\n");
return -1;
}
fsxattr.fsx_xflags = XFS_XFLAG_REALTIME;
fsxattr.fsx_extsize = EXTSIZE;
if (xfsctl(F_PATH, fd, XFS_IOC_FSSETXATTR, &fsxattr)) {
fprintf(stderr, "Set XFS attributes error!\n");
ret = -1;
goto out;
}
out:
close(fd);
return ret;
}
>
> I would suggest you take a look at the source of xfs_rctp(8) at xfsprogs to get
> more info.
xfs_rtcp really helps me a lot.
>
> BTW, I remember Dave once mentioned that the realtime feature on Linux is not widely
> tested and not recommended for production use.
>
However, I am wondering, now, I have created a XFS real-time file
named "rtfs.txt" and how I
could do some real-time stuffs on this file, which is different from
other common files.
--
Thanks
Weiwei Jia (Harry Wei)
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