Honor zfs_nocacheflush for file vdevs

For consistency with disk vdevs honor the zfs_nocacheflush tunable.
This setting is available primarily for debugging and performance
analysis.

Signed-off-by: HC <mmttdebbcc@yahoo.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #2336

diff --git a/module/zfs/vdev_file.c b/module/zfs/vdev_file.c
index 3305802241d7c63ebba0baba792551009643c244..8059cdea4400b57d2da8ece842046d30c4b63fa3 100644 (file)
--- a/module/zfs/vdev_file.c
+++ b/module/zfs/vdev_file.c
@@ -176,6 +176,10 @@ vdev_file_io_start(zio_t *zio)
 
                switch (zio->io_cmd) {
                case DKIOCFLUSHWRITECACHE:
+
+                       if (zfs_nocacheflush)
+                               break;
+
                        zio->io_error = VOP_FSYNC(vf->vf_vnode, FSYNC | FDSYNC,
                            kcred, NULL);
                        break;