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authorGerd Hoffmann <kraxel@redhat.com>2011-10-27 09:12:04 +0200
committerAnthony Liguori <aliguori@us.ibm.com>2011-11-01 11:50:21 -0500
commitaab2293687ee54a409f3fb53a1ab3595b595e0fb (patch)
tree32e34e0b63e52682db4d7e5b7d44b17ad1fa0179
parent695833bc8bbb9f1dbb0d7736cbe927863e1b40cd (diff)
migration: flush migration data to disk.
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>
-rw-r--r--migration-fd.c23
1 files changed, 22 insertions, 1 deletions
diff --git a/migration-fd.c b/migration-fd.c
index d0aec89e8d..6211124a05 100644
--- a/migration-fd.c
+++ b/migration-fd.c
@@ -42,10 +42,31 @@ static int fd_write(MigrationState *s, const void * buf, size_t size)
static int fd_close(MigrationState *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;
}