[libvirt] [PATCH] iohelper: Don't try to fdatasync(stdout)

[Christophe Fergeau]

After upgrading to libvirt 1.0.0, I've started getting warnings
from libvirt:
(gnome-boxes:5965): Libvirt.GObject-CRITICAL **: cannot finish stream:
internal error libvirt_iohelper: unable to fsync stdout: Invalid argument

On further investigation, in iohelper.c:runIO(), fdatasync can get called
on STDOUT_FILENO, which indeed returns EINVAL when this happens. After
making sure that fdout is not STDOUT_FILENO, this warning goes away.
---
 src/util/iohelper.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/util/iohelper.c b/src/util/iohelper.c
index 860e14a..f8a8ee3 100644
--- a/src/util/iohelper.c
+++ b/src/util/iohelper.c
@@ -180,9 +180,11 @@ runIO(const char *path, int fd, int oflags, unsigned long long length)
     }
 
     /* Ensure all data is written */
-    if (fdatasync(fdout) < 0) {
-        virReportSystemError(errno, _("unable to fsync %s"), fdoutname);
-        goto cleanup;
+    if (fdout != STDOUT_FILENO) {
+        if (fdatasync(fdout) < 0) {
+            virReportSystemError(errno, _("unable to fsync %s"), fdoutname);
+            goto cleanup;
+        }
     }
 
     ret = 0;
-- 
1.7.12.1