Re: [PATCH v2 2/2] xfstests: introduce 280 for SEEK_DATA/SEEK_HOLE copy check

Mark Tinguely
2012-02-06T22:30:14Z

On 02/06/12 08:30, Jeff Liu wrote:
> Introduce 280 for SEEK_DATA/SEEK_HOLE copy check.
>
> Signed-off-by: Jie Liu<jeff.liu@oracle.com>
>
> ---

>
> diff --git a/src/seek_copy_tester.c b/src/seek_copy_tester.c
> new file mode 100644
> index 0000000..ddf683f
> --- /dev/null
> +++ b/src/seek_copy_tester.c

> +static size_t
> +full_write(int fd, const void *buf, size_t count)
> +{
> + size_t total = 0;
> + const char *ptr = (const char *) buf;
> +
> + while (count> 0) {
> + ssize_t n = write(fd, ptr, count);
> + if (n< 0) {
> + if (errno == EINTR)
> + continue;

Wouldn't you want to stop the write loop if interrupted?

> + error("full_write() failed as %s", strerror(errno));
> + break;
> + }
> +
> + if (n == 0) {
> + error("full_write() ZERO bytes transferred");

You can tell them how many (total) bytes were written before the error.
Same in full_pwrite()

> +create_data_and_holes(int fd, size_t nr_total_bytes, off_t start_offset,
> + uint64_t nr_skip_bytes, uint64_t nr_data_bytes,
> + int wrote_hole_at_eof)
> +{
> + int ret = 0;
> + off_t total = nr_total_bytes;
> + off_t data_len = nr_data_bytes;
> + off_t off = start_offset;
> + char buf[BUF_SIZE];
> +
> + memset(buf, 'A', sizeof(buf));
> +
> + total -= start_offset;
> + while (total> 0) {

+ data_len = nr_data_bytes; /* see below */

> + do {
> + size_t nr_write = MIN(total, BUF_SIZE);

There are 2 dependencies:
1) The last nr_data_bytes does not exceed total (outer loop)
2) The remaining data size (data_len) could be less than BUF_SIZE
(if data_len is not a multiple of BUF_SIZE for example).

> + if (full_pwrite(fd, buf, nr_write, off) != nr_write) {
> + error("full_pwrite() failed as %s", strerror(errno));
> + ret = -1;
> + goto out;
> + }
> +
> + off += nr_write;
> + data_len -= nr_write;
> + } while (data_len> 0);

data_len is <= 0 so the inner loop will execute only once if you have
more than one chunk of data.
> +
> + off += (nr_skip_bytes + nr_data_bytes);
> + total -= off;
> + }
> +
> + if (off< nr_total_bytes) {
> + if (wrote_hole_at_eof) {
> + ret = ftruncate(fd, nr_total_bytes);
> + if (ret< 0) {
> + error("truncate source file to %lld bytes failed as %s",
> + (long long)nr_total_bytes, strerror(errno));
> + }
> + }
> +
> + ret = write_zeros(fd, nr_total_bytes - off);
> + if (ret< 0) {
> + error("write_zeros to end of file failed as %s",
> + strerror(errno));
> + }
> + }
> +
> +out:
> + return ret;
> +}

It is shaping up nicely.

--Mark