ask the detail about 'read' and 'write' in sanlock

[tsiren tsi]

Hi, all

I hava read the source code of sanlock some days. But I have a question, it
is that why scsi command was not used in the 'diskio.c'? The scsi command
can catch much more exception the io.

Could someone help me?

diskio.c

/* write aligned io buffer */

int write_iobuf(int fd, uint64_t offset, char *iobuf, int iobuf_len,
        struct task *task, int ioto)
{
    if (task && task->use_aio == 1)
        return do_write_aio_linux(fd, offset, iobuf, iobuf_len, task, ioto);
    else if (task && task->use_aio == 2)
        return do_write_aio_posix(fd, offset, iobuf, iobuf_len, task, ioto);
    else
        return do_write(fd, offset, iobuf, iobuf_len, task);
}