diff mbox

[stable-0.15,12/36] migration: flush migration data to disk.

Message ID 1332939159-16434-13-git-send-email-afaerber@suse.de
State New
Headers show

Commit Message

Andreas Färber March 28, 2012, 12:52 p.m. UTC 
From: Gerd Hoffmann <kraxel@redhat.com>

This patch increases robustness when migrating to a file with
two little changes:

 (1) Before closing the migration file handle checks if it happens to be
     a regular file and if so it issues a fsync.  This way the data is
     flushed to disk before qemu sends the migration completed event.
 (2) It adds error checking.  In case either fsync or close syscall
     fails pass up the error (and fail migration).

[ v2: return -errno instead of -1 ]

Cc: Juan Quintela <quintela@redhat.com>
Cc: Jiri Denemark <jdenemar@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
(cherry picked from commit aab2293687ee54a409f3fb53a1ab3595b595e0fb)

Signed-off-by: Bruce Rogers <brogers@suse.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
 migration-fd.c |   23 ++++++++++++++++++++++-
 1 files changed, 22 insertions(+), 1 deletions(-)
diff mbox

Patch

diff --git a/migration-fd.c b/migration-fd.c
index 66d51c1..f986bdf 100644
--- a/migration-fd.c
+++ b/migration-fd.c
@@ -42,10 +42,31 @@  static int fd_write(FdMigrationState *s, const void * buf, size_t size)
 
 static int fd_close(FdMigrationState *s)
 {
+    struct stat st;
+    int ret;
+
     DPRINTF("fd_close\n");
     if (s->fd != -1) {
-        close(s->fd);
+        ret = fstat(s->fd, &st);
+        if (ret == 0 && S_ISREG(st.st_mode)) {
+            /*
+             * If the file handle is a regular file make sure the
+             * data is flushed to disk before signaling success.
+             */
+            ret = fsync(s->fd);
+            if (ret != 0) {
+                ret = -errno;
+                perror("migration-fd: fsync");
+                return ret;
+            }
+        }
+        ret = close(s->fd);
         s->fd = -1;
+        if (ret != 0) {
+            ret = -errno;
+            perror("migration-fd: close");
+            return ret;
+        }
     }
     return 0;
 }