On Wed, Jan 23, 2013 at 07:04:33PM +0800, Chen Yang wrote:
> When sending a file with sparse or pre-allocated part,
> these parts will be sent as ZERO streams, and it's unnecessary.
>
> To improve this, we add a punch command on the sending side, so the
> receiving side changed with it. The main change is adding the punch
> processing to receive command.
>
> +static int process_punch(const char *path, u64 offset, u64 len, void *user)
> +{
> + int ret = 0;
> + struct btrfs_receive *r = user;
> + char *full_path = path_cat(r->full_subvol_path, path);
> +
> + ret = open_inode_for_write(r, full_path);
> + if (ret < 0)
> + goto out;
> +
> + ret = fallocate(r->write_fd,
> + FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> + offset, len);
This unnecessarily fails if PUNCH_HOLE is not supported by the kernel
version, some sort of fallback should be applied.
> + if (ret < 0) {
> + ret = -errno;
> + fprintf(stderr, "ERROR: punch %s failed. %s\n",
> + path, strerror(-ret));
> + goto out;
> + }
> +
> +out:
> + free(full_path);
> + return ret;
> +}
david
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