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aab2293687
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>
127 lines
2.8 KiB
C
127 lines
2.8 KiB
C
/*
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* QEMU live migration via generic fd
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*
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* Copyright Red Hat, Inc. 2009
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*
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* Authors:
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* Chris Lalancette <clalance@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h"
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#include "qemu_socket.h"
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#include "migration.h"
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#include "monitor.h"
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#include "qemu-char.h"
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#include "buffered_file.h"
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#include "block.h"
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#include "qemu_socket.h"
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//#define DEBUG_MIGRATION_FD
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#ifdef DEBUG_MIGRATION_FD
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#define DPRINTF(fmt, ...) \
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do { printf("migration-fd: " fmt, ## __VA_ARGS__); } while (0)
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#else
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#define DPRINTF(fmt, ...) \
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do { } while (0)
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#endif
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static int fd_errno(MigrationState *s)
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{
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return errno;
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}
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static int fd_write(MigrationState *s, const void * buf, size_t size)
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{
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return write(s->fd, buf, size);
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}
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static int fd_close(MigrationState *s)
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{
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struct stat st;
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int ret;
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DPRINTF("fd_close\n");
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if (s->fd != -1) {
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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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int fd_start_outgoing_migration(MigrationState *s, const char *fdname)
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{
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s->fd = monitor_get_fd(s->mon, fdname);
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if (s->fd == -1) {
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DPRINTF("fd_migration: invalid file descriptor identifier\n");
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goto err_after_get_fd;
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}
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if (fcntl(s->fd, F_SETFL, O_NONBLOCK) == -1) {
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DPRINTF("Unable to set nonblocking mode on file descriptor\n");
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goto err_after_open;
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}
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s->get_error = fd_errno;
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s->write = fd_write;
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s->close = fd_close;
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migrate_fd_connect(s);
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return 0;
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err_after_open:
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close(s->fd);
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err_after_get_fd:
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return -1;
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}
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static void fd_accept_incoming_migration(void *opaque)
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{
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QEMUFile *f = opaque;
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process_incoming_migration(f);
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qemu_set_fd_handler2(qemu_stdio_fd(f), NULL, NULL, NULL, NULL);
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qemu_fclose(f);
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}
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int fd_start_incoming_migration(const char *infd)
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{
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int fd;
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QEMUFile *f;
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DPRINTF("Attempting to start an incoming migration via fd\n");
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fd = strtol(infd, NULL, 0);
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f = qemu_fdopen(fd, "rb");
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if(f == NULL) {
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DPRINTF("Unable to apply qemu wrapper to file descriptor\n");
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return -errno;
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}
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qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);
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return 0;
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}
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