On Fri, Oct 16, 2020 at 11:35:55PM -0500, Eric Blake wrote:
> Otherwise, we get a failure due to Numerical result out of range.
>
> And for safety's sake, we are best capping our request to an aligned
> value, if the server insists on minimum alignment.
>
> Fixes: f3fd935c
> ---
> info/nbdinfo.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/info/nbdinfo.c b/info/nbdinfo.c
> index 1afdf98..2b22f51 100644
> --- a/info/nbdinfo.c
> +++ b/info/nbdinfo.c
> @@ -31,6 +31,8 @@
>
> #include <libnbd.h>
>
> +#define MIN(a,b) ((a) < (b) ? (a) : (b))
I suppose we could import the min & max macros from nbdkit
common/include/minmax.h. However that's a larger change.
> static const char *progname;
> static FILE *fp;
> static bool list_all = false;
> @@ -267,7 +269,7 @@ main (int argc, char *argv[])
> fprintf (fp, "%" PRIi64 "\n", size);
> }
> else if (map) { /* --map (!list_all) */
> - uint64_t offset, prev_offset;
> + uint64_t offset, prev_offset, align, max_len;
>
> /* Did we get the requested map? */
> if (!nbd_can_meta_context (nbd, map)) {
> @@ -276,6 +278,8 @@ main (int argc, char *argv[])
> progname, map);
> exit (EXIT_FAILURE);
> }
> + align = nbd_get_block_size (nbd, LIBNBD_SIZE_MINIMUM) ?: 512;
> + max_len = UINT32_MAX - align + 1;
>
> size = nbd_get_size (nbd);
> if (size == -1) {
> @@ -286,7 +290,7 @@ main (int argc, char *argv[])
> if (json_output) fprintf (fp, "[\n");
> for (offset = 0; offset < size;) {
> prev_offset = offset;
> - if (nbd_block_status (nbd, size - offset, offset,
> + if (nbd_block_status (nbd, MIN (size - offset, max_len), offset,
> (nbd_extent_callback) { .callback =
> extent_callback,
> .user_data = &offset },
> 0) == -1) {
> --
> 2.29.0.rc1
ACK
Thanks,
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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