Fix qemu-img broken in 0.5.11

Caused by the lack of reenterability of the main cluster_client function

src/cluster_client.cpp

@@ -95,6 +95,14 @@ void cluster_client_t::continue_ops(bool up_retry)
         // We're offline
         return;
     }
+    if (continuing_ops)
+    {
+        // Attempt to reenter the function
+        continuing_ops = 2;
+        return;
+    }
+restart:
+    continuing_ops = 1;
     bool has_flushes = false, has_writes = false;
     int j = 0;
     for (int i = 0; i < op_queue.size(); i++)
@@ -141,6 +149,14 @@ void cluster_client_t::continue_ops(bool up_retry)
         }
     }
     op_queue.resize(j);
+    if (continuing_ops == 2)
+    {
+        goto restart;
+    }
+    else
+    {
+        continuing_ops = 0;
+    }
 }
 
 static uint32_t is_power_of_two(uint64_t value)

src/cluster_client.h

@@ -82,6 +82,7 @@ class cluster_client_t
     bool pgs_loaded = false;
     ring_consumer_t consumer;
     std::vector<std::function<void(void)>> on_ready_hooks;
+    int continuing_ops = 0;
 
 public:
     etcd_state_client_t st_cli;

tests/test_write.sh

@@ -35,6 +35,14 @@ fi
 #    fio -thread -name=test -ioengine=build/src/libfio_vitastor_sec.so -bs=4k -fsync=128 `$ETCDCTL get /vitastor/osd/state/1 --print-value-only | jq -r '"-host="+.addresses[0]+" -port="+(.port|tostring)'` -rw=write -size=32M
 
 LD_PRELOAD=libasan.so.5 \
-    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=4M -direct=1 -iodepth=1 -fsync=1 -rw=write -etcd=$ETCD_URL -pool=1 -inode=1 -size=1G -cluster_log_level=10
+    fio -thread -name=test -ioengine=build/src/libfio_vitastor.so -bs=4M -direct=1 -iodepth=1 -fsync=1 -rw=write -etcd=$ETCD_URL -pool=1 -inode=1 -size=128M -cluster_log_level=10
+
+qemu-img convert -S 4096 -p \
+    -f raw "vitastor:etcd_host=127.0.0.1\:$ETCD_PORT/v3:pool=1:inode=1:size=$((128*1024*1024))" \
+    -O raw ./testdata/read.bin
+
+qemu-img convert -S 4096 -p \
+    -f raw ./testdata/read.bin \
+    -O raw "vitastor:etcd_host=127.0.0.1\:$ETCD_PORT/v3:pool=1:inode=1:size=$((128*1024*1024))"
 
 format_green OK