On Fri, Sep 24, 2010 at 04:33:05PM +0200, Jens Axboe wrote: > On 2010-09-23 01:21, Valerie Aurora wrote: > > On Mon, Sep 20, 2010 at 08:04:10PM +0200, Miklos Szeredi wrote: > >> From: Miklos Szeredi <mszeredi@xxxxxxx> > >> > >> This overlay filesystem is a hybrid of entirely filesystem based > >> (unionfs, aufs) and entierly VFS based (union mounts) solutions. > > > > [...] > > > >> +static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) > >> +{ > >> + struct file *old_file; > >> + struct file *new_file; > >> + int error = 0; > >> + > >> + if (len == 0) > >> + return 0; > >> + > >> + old_file = path_open(old, O_RDONLY); > >> + if (IS_ERR(old_file)) > >> + return PTR_ERR(old_file); > >> + > >> + new_file = path_open(new, O_WRONLY); > >> + if (IS_ERR(new_file)) { > >> + error = PTR_ERR(new_file); > >> + goto out_fput; > >> + } > >> + > >> + /* FIXME: copy up sparse files efficiently */ > >> + while (len) { > >> + loff_t offset = new_file->f_pos; > >> + size_t this_len = OVL_COPY_UP_CHUNK_SIZE; > >> + long bytes; > >> + > >> + if (len < this_len) > >> + this_len = len; > >> + > >> + if (signal_pending_state(TASK_KILLABLE, current)) > >> + return -EINTR; > >> + > >> + bytes = do_splice_direct(old_file, &offset, new_file, this_len, > >> + SPLICE_F_MOVE); > > > > Interruptible copyup is good. But it looks like splice setup is kind > > of heavyweight and we should do it as seldom as possible. > > > > What about implementing splice flag SPLICE_F_INTERRUPTIBLE instead? > > The pipe alloc and such? That is lazily done and sticks around. Thanks! So this looks like a good way to implement interruptible in-kernel file copyup? -VAL -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html