rgw: add check for ACL when create existing bucket

[cbodley]

some cleanups for #35170:

• use composition of operator==()s to avoid having to encode buffers for comparison
• adds operator!=()s
• changes the create_bucket() policy argument from an optional pointer to a const reference
• moves the acl owner comparison into operator==()

Fixes: https://tracker.ceph.com/issues/47028

Checklist

• References tracker ticket
• Updates documentation if necessary
• Includes tests for new functionality or reproducer for bug

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[BryceCao]

LGTM, brevity code.

[cbodley]

i wrote an s3test case for this and it doesn't appear to work. there's extra code in RGWCreateBucket::execute() that handles this -EEXIST error and falls back to an owner comparison. i don't fully understand the retry logic in if (need_metadata_upload() && existed), but that's probably related to the tempest test failures

[cbodley]

see test cases in ceph/s3-tests#356

[cbodley]

@dang it looks like my latest commit resolved the tempest test failures in test_create_container_with_remove_metadata_key and test_create_container_with_remove_metadata_value. can you please review that one?

https://pulpito.ceph.com/cbodley-2020-09-11_14:01:23-rgw-wip-cbodley-testing-distro-basic-smithi/

[cbodley]

still having issues with the multisite test_bucket_create() here. when creating a bucket on a secondary zone, it forwards the request to the master first. after that, we go on to call RGWRados::create_bucket(), but that returns -EEXIST if metadata sync raced to create the bucket instance first

[dang]

How about this:

diff --git a/src/rgw/rgw_sal_rados.cc b/src/rgw/rgw_sal_rados.cc
index 4902e72a84c..ba4168e7320 100644
--- a/src/rgw/rgw_sal_rados.cc
+++ b/src/rgw/rgw_sal_rados.cc
@@ -925,6 +925,7 @@ int RGWRadosStore::create_bucket(RGWUser& u, const rgw_bucket& b,
                                    pmaster_bucket, pmaster_num_shards, exclusive);
     if (ret == -EEXIST) {
       *existed = true;
+      ret = 0;
     } else if (ret != 0) {
       return ret;
     }

[cbodley]

thanks, that did it! https://pulpito.ceph.com/cbodley-2020-09-14_18:11:23-rgw-wip-cbodley-testing-distro-basic-smithi/