Fix: sync buffer file metadata on buffer allocation

[lttng-ust.git] / libringbuffer / shm.c

diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c
index c4c651e4b925543e373e9b016398636be4c03293..8ac321e3931906888f79dd9e2419a7dbca8225de 100644 (file)
--- a/libringbuffer/shm.c
+++ b/libringbuffer/shm.c
@@ -39,6 +39,9 @@
  * Ensure we have the required amount of space available by writing 0
  * into the entire buffer. Not doing so can trigger SIGBUS when going
  * beyond the available shm space.
+ *
+ * Also ensure the file metadata is synced with the storage by using
+ * fsync(2).
  */
 static
 int zero_file(int fd, size_t len)
@@ -67,6 +70,11 @@ int zero_file(int fd, size_t len)
                }
                written += retlen;
        }
+       ret = fsync(fd);
+       if (ret) {
+               ret = (int) -errno;
+               goto error;
+       }
        ret = 0;
 error:
        free(zeropage);