From: Yuval Lifshitz <yuvalif@yahoo.com>
Date: Tue, 3 Mar 2020 10:15:02 +0000 (+0200)
Subject: cls/queue: fix data corruption in urgent data
X-Git-Tag: v15.1.1~72^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=5efbd86a6e71dba5e7b77d6c22cda0132a67ddbc;p=ceph.git

cls/queue: fix data corruption in urgent data

when queue size exceeded 1K, urgent data was currupted
this was happening even if the urgent data size was set correctly

Signed-off-by: Yuval Lifshitz <yuvalif@yahoo.com>
---

diff --git a/src/cls/queue/cls_queue_src.cc b/src/cls/queue/cls_queue_src.cc
index 59fa626695ff..b48dcd19f851 100644
--- a/src/cls/queue/cls_queue_src.cc
+++ b/src/cls/queue/cls_queue_src.cc
@@ -38,7 +38,7 @@ int queue_read_head(cls_method_context_t hctx, cls_queue_head& head)
   uint64_t chunk_size = 1024, start_offset = 0;
 
   bufferlist bl_head;
-  int ret = cls_cxx_read(hctx, start_offset, chunk_size, &bl_head);
+  const auto  ret = cls_cxx_read(hctx, start_offset, chunk_size, &bl_head);
   if (ret < 0) {
     CLS_LOG(5, "ERROR: queue_read_head: failed to read head\n");
     return ret;
@@ -67,12 +67,12 @@ int queue_read_head(cls_method_context_t hctx, cls_queue_head& head)
     return -EINVAL;
   }
 
-  uint8_t decoded_head_size = sizeof(uint64_t) + sizeof(uint16_t);
+  constexpr auto decoded_head_size = sizeof(queue_head_start) + sizeof(encoded_len);
   if (encoded_len > (chunk_size - decoded_head_size)) {
+    start_offset = chunk_size;
     chunk_size = (encoded_len - (chunk_size - decoded_head_size));
-    start_offset += decoded_head_size;
     bufferlist bl_remaining_head;
-    int ret = cls_cxx_read2(hctx, start_offset, chunk_size, &bl_remaining_head, CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL);
+    const auto ret = cls_cxx_read2(hctx, start_offset, chunk_size, &bl_remaining_head, CEPH_OSD_OP_FLAG_FADVISE_SEQUENTIAL);
     if (ret < 0) {
       CLS_LOG(5, "ERROR: queue_read_head: failed to read remaining part of head\n");
       return ret;