Re: [Libguestfs] [nbdkit PATCH] retry: Tweak error message

The retry filter defaults to 5 retries, but when run with verbose details produces some confusing output: $ rm -f /tmp/inject; (sleep 5s; touch /tmp/inject)& ./nbdkit -f -v -U - \ null 1G --filter=retry --filter=noextents --filter=error error-rate=100% \ error-file=/tmp/inject --filter=delay rdelay=1 \ --run 'qemu-img convert $nbd out.img' ... nbdkit: null[1]: debug: noextents: pread count=2097152 offset=14680064 nbdkit: null[1]: debug: error: pread count=2097152 offset=14680064 nbdkit: null[1]: error: injecting EIO error into pread nbdkit: null[1]: debug: retry 6: original errno = 5 nbdkit: null[1]: debug: could not recover after 5 retries The code is correct (there were six attempts, but that corresponds to 5 retries after the initial attempt; comments mention that retry=0 turns the filter into a no-op but even that requires an initial attempt). So all we need to adjust is the output. Fixes: f0f0ec49 Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- I'm pushing this in response to https://bugzilla.redhat.com/1819240 At the same time, I'm looking at whether qemu-img should be tweaked to have a mode where it gives up on the first EIO error, rather than plowing on through the rest of the image even after the first error. filters/retry/retry.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/filters/retry/retry.c b/filters/retry/retry.c index 11e5313b..db91d7ca 100644 --- a/filters/retry/retry.c +++ b/filters/retry/retry.c @@ -173,7 +173,7 @@ do_retry (struct retry_handle *h, again: /* Log the original errno since it will be lost when we retry. */ - nbdkit_debug ("retry %d: original errno = %d", data->retry+1, *err); + nbdkit_debug ("retry attempt %d: original errno = %d", data->retry, *err); if (data->retry >= retries) { nbdkit_debug ("could not recover after %d retries", retries);