Fix: 4.10 btrfs instrumentation update backward compat

[lttng-modules.git] / lttng-abi.c

diff --git a/lttng-abi.c b/lttng-abi.c
index 87465189060edd4122cc9f8c5ad87c3fe218b6f1..397e1de6dd5848a0603a53a26fc264af1e65b3fd 100644 (file)
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -702,6 +702,18 @@ long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 
                return put_u64(stream->version, arg);
        }
+       case RING_BUFFER_SNAPSHOT:
+       {
+               /*
+                * Force the buffer to quiescent so the ring buffer
+                * don't attempt to perform a SWITCH_FLUSH, which would
+                * desynchronize the client accounting of the amount of
+                * data available in the buffer from the ring buffer
+                * view.
+                */
+               buf->quiescent = true;
+               break;
+       }
        default:
                break;
        }
@@ -778,6 +790,18 @@ long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
 
                return put_u64(stream->version, arg);
        }
+       case RING_BUFFER_SNAPSHOT:
+       {
+               /*
+                * Force the buffer to quiescent so the ring buffer
+                * don't attempt to perform a SWITCH_FLUSH, which would
+                * desynchronize the client accounting of the amount of
+                * data available in the buffer from the ring buffer
+                * view.
+                */
+               buf->quiescent = true;
+               break;
+       }
        default:
                break;
        }
@@ -972,8 +996,11 @@ int lttng_abi_open_metadata_stream(struct file *channel_file)
                goto notransport;
        }
 
-       if (!lttng_kref_get(&session->metadata_cache->refcount))
+       if (!lttng_kref_get(&session->metadata_cache->refcount)) {
+               ret = -EOVERFLOW;
                goto kref_error;
+       }
+
        ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
                        &lttng_metadata_ring_buffer_file_operations);
        if (ret < 0)