[libvirt] [PATCH] storage: Flush host cache after write

[Michal Privoznik]

Although we are flushing cache after some critical writes (e.g.
volume creation), after some others we do not (e.g. volume cloning).
This patch fix this issue. That is for volume cloning, writing
header of logical volume, and storage wipe.
---
 src/storage/storage_backend.c         |    8 ++++++++
 src/storage/storage_backend_logical.c |    7 +++++++
 src/storage/storage_driver.c          |    8 ++++++++
 3 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index 6243d1e..889f530 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -208,6 +208,14 @@ virStorageBackendCopyToFD(virStorageVolDefPtr vol,
         } while ((amtleft -= interval) > 0);
     }
 
+    if (fdatasync(fd) < 0) {
+        ret = -errno;
+        virReportSystemError(errno, _("cannot sync data to file '%s'"),
+                             vol->target.path);
+        goto cleanup;
+    }
+
+
     if (VIR_CLOSE(inputfd) < 0) {
         ret = -errno;
         virReportSystemError(errno,
diff --git a/src/storage/storage_backend_logical.c b/src/storage/storage_backend_logical.c
index c622d2a..ca4166d 100644
--- a/src/storage/storage_backend_logical.c
+++ b/src/storage/storage_backend_logical.c
@@ -424,6 +424,13 @@ virStorageBackendLogicalBuildPool(virConnectPtr conn ATTRIBUTE_UNUSED,
             VIR_FORCE_CLOSE(fd);
             goto cleanup;
         }
+        if (fsync(fd) < 0) {
+            virReportSystemError(errno,
+                                 _("cannot flush header of device'%s'"),
+                                 pool->def->source.devices[i].path);
+            VIR_FORCE_CLOSE(fd);
+            goto cleanup;
+        }
         if (VIR_CLOSE(fd) < 0) {
             virReportSystemError(errno,
                                  _("cannot close device '%s'"),
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 6715790..68cac1f 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1777,6 +1777,14 @@ storageWipeExtent(virStorageVolDefPtr vol,
         remaining -= written;
     }
 
+    if (fdatasync(fd) < 0) {
+        ret = -errno;
+        virReportSystemError(errno,
+                             _("cannot sync data to volume with path '%s'"),
+                             vol->target.path);
+        goto out;
+    }
+
     VIR_DEBUG("Wrote %zu bytes to volume with path '%s'",
               *bytes_wiped, vol->target.path);
 
-- 
1.7.3.4