From 324c377849a5d246f689f6e7a2862f42f1504d2c Mon Sep 17 00:00:00 2001
From: Mark Kogan <mkogan@redhat.com>
Date: Mon, 5 Apr 2021 15:49:42 +0300
Subject: [PATCH] rgw: return OK on consecutive complete-multipart reqs

Fixes: https://tracker.ceph.com/issues/50141

Signed-off-by: Mark Kogan <mkogan@redhat.com>

fixup! rgw: return OK on consecutive complete-multipart reqs
---
 src/rgw/rgw_op.cc | 43 +++++++++++++++++++++++++++++++++++++++++++
 src/rgw/rgw_op.h  |  1 +
 2 files changed, 44 insertions(+)

diff --git a/src/rgw/rgw_op.cc b/src/rgw/rgw_op.cc
index e66a5b85719a6..6fbd7cf2850ca 100644
--- a/src/rgw/rgw_op.cc
+++ b/src/rgw/rgw_op.cc
@@ -5956,6 +5956,11 @@ void RGWCompleteMultipart::execute(optional_yield y)
   op_ret = serializer->try_lock(dur, y);
   if (op_ret < 0) {
     ldpp_dout(this, 0) << "failed to acquire lock" << dendl;
+    if (op_ret == -ENOENT && check_previously_completed(this, parts)) {
+      ldpp_dout(this, 1) << "NOTICE: This multipart completion is already completed" << dendl;
+      op_ret = 0;
+      return;
+    }
     op_ret = -ERR_INTERNAL_ERROR;
     s->err.message = "This multipart completion is already in progress";
     return;
@@ -6139,6 +6144,44 @@ void RGWCompleteMultipart::execute(optional_yield y)
   }
 }
 
+bool RGWCompleteMultipart::check_previously_completed(const DoutPrefixProvider* dpp, const RGWMultiCompleteUpload* parts)
+{
+  // re-calculate the etag from the parts and compare to the existing object
+  s->object->set_bucket(s->bucket.get());
+  int ret = s->object->get_obj_attrs(s->obj_ctx, s->yield, this);
+  if (ret < 0) {
+    ldpp_dout(dpp, 0) << __func__ << "() ERROR: get_obj_attrs() returned ret=" << ret << dendl;
+    return false;
+  }
+  rgw::sal::Attrs sattrs = s->object->get_attrs();
+  string oetag = sattrs[RGW_ATTR_ETAG].to_str();
+
+  MD5 hash;
+  for (const auto& [index, part] : parts->parts) {
+    std::string partetag = rgw_string_unquote(part);
+    char petag[CEPH_CRYPTO_MD5_DIGESTSIZE];
+    hex_to_buf(partetag.c_str(), petag, CEPH_CRYPTO_MD5_DIGESTSIZE);
+    hash.Update((const unsigned char *)petag, sizeof(petag));
+    ldpp_dout(dpp, 20) << __func__ << "() re-calculating multipart etag: part: "
+                                   << index << ", etag: " << partetag << dendl;
+  }
+
+  unsigned char final_etag[CEPH_CRYPTO_MD5_DIGESTSIZE];
+  char final_etag_str[CEPH_CRYPTO_MD5_DIGESTSIZE * 2 + 16];
+  hash.Final(final_etag);
+  buf_to_hex(final_etag, CEPH_CRYPTO_MD5_DIGESTSIZE, final_etag_str);
+  snprintf(&final_etag_str[CEPH_CRYPTO_MD5_DIGESTSIZE * 2], sizeof(final_etag_str) - CEPH_CRYPTO_MD5_DIGESTSIZE * 2,
+           "-%lld", (long long)parts->parts.size());
+
+  if (oetag.compare(final_etag_str) != 0) {
+    ldpp_dout(dpp, 1) << __func__ << "() NOTICE: etag mismatch: object etag:"
+                                  << oetag << ", re-calculated etag:" << final_etag_str << dendl;
+    return false;
+  }
+  ldpp_dout(dpp, 5) << __func__ << "() object etag and re-calculated etag match, etag: " << oetag << dendl;
+  return true;
+}
+
 void RGWCompleteMultipart::complete()
 {
   /* release exclusive lock iff not already */
diff --git a/src/rgw/rgw_op.h b/src/rgw/rgw_op.h
index 3de1b5d3b34b6..0e746b6be8161 100644
--- a/src/rgw/rgw_op.h
+++ b/src/rgw/rgw_op.h
@@ -1815,6 +1815,7 @@ public:
   int verify_permission(optional_yield y) override;
   void pre_exec() override;
   void execute(optional_yield y) override;
+  bool check_previously_completed(const DoutPrefixProvider* dpp, const RGWMultiCompleteUpload* parts);
   void complete() override;
 
   virtual int get_params(optional_yield y) = 0;
-- 
2.39.5