From: Shilpa Jagannath <smanjara@redhat.com>
Date: Mon, 8 Dec 2025 17:48:53 +0000 (-0500)
Subject: rgw/reshard: bucket reshard may race with bucket index update.
X-Git-Tag: v21.0.0~311^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=e34067f8ceab85d9eb97eecd7d6f753e82747930;p=ceph.git

rgw/reshard: bucket reshard may race with bucket index update.
guard_reshard() serves as a wrapper to protect bucket index operations
against concurrent resharding. but it only handles -ERR_BUSY_RESHARDING
if bucket index update is already in progress with bucket shard
assigned, and a concurrent resharding operation deletes this old shard
object, there may be a window of operations targeting the old shards
failing with -ENOENT. this error is not caught anywhere in the calling
functions. as a result we could end up with objects in an inconsistent state.

Signed-off-by: Shilpa Jagannath <smanjara@redhat.com>
---

diff --git a/src/rgw/driver/rados/rgw_rados.cc b/src/rgw/driver/rados/rgw_rados.cc
index 4e861f937767..a1dac761cd9d 100644
--- a/src/rgw/driver/rados/rgw_rados.cc
+++ b/src/rgw/driver/rados/rgw_rados.cc
@@ -7974,6 +7974,12 @@ int RGWRados::Bucket::UpdateIndex::guard_reshard(const DoutPrefixProvider *dpp,
     }
 
     r = call(bs);
+    if (r == -ENOENT) {
+      ldpp_dout(dpp, 10) << "ENOENT in guard_reshard(), likely bucket resharding, retrying" << dendl;
+      invalidate_bs();
+      continue;
+    }
+
     if (r != -ERR_BUSY_RESHARDING) {
       break;
     }
@@ -8678,6 +8684,10 @@ int RGWRados::guard_reshard(const DoutPrefixProvider *dpp,
     }
 
     r = call(bs);
+    if (r == -ENOENT) {
+      ldpp_dout(dpp, 10) << "ENOENT in guard_reshard(), likely bucket resharding, retrying" << dendl;
+      continue;
+    }
     if (r != -ERR_BUSY_RESHARDING) {
       break;
     }