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From 06400ebc136bf44f1fa423159fae9cc9a4f6839d Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Thu, 27 Oct 2011 09:12:04 +0200
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Subject: [PATCH] migration: flush migration data to disk.
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This patch increases robustness when migrating to a file with
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two little changes:
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(1) Before closing the migration file handle checks if it happens to be
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a regular file and if so it issues a fsync. This way the data is
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flushed to disk before qemu sends the migration completed event.
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(2) It adds error checking. In case either fsync or close syscall
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fails pass up the error (and fail migration).
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[ v2: return -errno instead of -1 ]
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Cc: Juan Quintela <quintela@redhat.com>
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Cc: Jiri Denemark <jdenemar@redhat.com>
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
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(cherry picked from commit aab2293687ee54a409f3fb53a1ab3595b595e0fb)
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Signed-off-by: Bruce Rogers <brogers@suse.com>
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Signed-off-by: Andreas Färber <afaerber@suse.de>
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---
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migration-fd.c | 23 ++++++++++++++++++++++-
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1 file changed, 22 insertions(+), 1 deletion(-)
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diff --git a/migration-fd.c b/migration-fd.c
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index 66d51c1..f986bdf 100644
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--- a/migration-fd.c
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+++ b/migration-fd.c
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@@ -42,10 +42,31 @@ static int fd_write(FdMigrationState *s, const void * buf, size_t size)
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static int fd_close(FdMigrationState *s)
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{
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+ struct stat st;
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+ int ret;
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+
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DPRINTF("fd_close\n");
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if (s->fd != -1) {
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- close(s->fd);
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+ ret = fstat(s->fd, &st);
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+ if (ret == 0 && S_ISREG(st.st_mode)) {
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+ /*
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+ * If the file handle is a regular file make sure the
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+ * data is flushed to disk before signaling success.
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+ */
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+ ret = fsync(s->fd);
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+ if (ret != 0) {
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+ ret = -errno;
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+ perror("migration-fd: fsync");
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+ return ret;
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+ }
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+ }
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+ ret = close(s->fd);
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s->fd = -1;
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+ if (ret != 0) {
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+ ret = -errno;
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+ perror("migration-fd: close");
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+ return ret;
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+ }
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}
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return 0;
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}
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--
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1.7.11.2
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