The below set of patches implement open by handle support using exportfs
operations. This allows user space application to map a file name to file
handle and later open the file using handle. This should be usable
for userspace NFS and 9P server. XFS already support this with the ioctls
XFS_IOC_PATH_TO_HANDLE and XFS_IOC_OPEN_BY_HANDLE.
Example program:
-------------
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
struct file_handle {
int handle_size;
int handle_type;
void *f_handle;
};
int main(int argc, char *argv[])
{
int ret;
int fd;
char buf[100];
struct file_handle fh;
fh.handle_type = 0;
fh.handle = malloc(100);
fh.handle_size = 100/sizeof(int);
errno = 0;
ret = syscall(338, argv[1], &fh);
if (ret) {
perror("Error:");
exit(1);
}
printf("%d\n",fh.handle_size);
fd = syscall(339, &fh, O_RDONLY);
if (fd <= 0 ) {
perror("Error:");
exit(1);
}
printf("fd = %d\n", fd);
memset(buf, 0 , 100);
while (read(fd, buf, 100) > 0) {
printf("%s", buf);
memset(buf, 0 , 100);
}
return 0;
}
-aneesh
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