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[PULL 10/11] migration: file URI offset
From: |
Juan Quintela |
Subject: |
[PULL 10/11] migration: file URI offset |
Date: |
Wed, 4 Oct 2023 14:40:37 +0200 |
From: Steve Sistare <steven.sistare@oracle.com>
Allow an offset option to be specified as part of the file URI, in
the form "file:filename,offset=offset", where offset accepts the common
size suffixes, or the 0x prefix, but not both. Migration data is written
to and read from the file starting at offset. If unspecified, it defaults
to 0.
This is needed by libvirt to store its own data at the head of the file.
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-ID: <1694182931-61390-3-git-send-email-steven.sistare@oracle.com>
---
migration/file.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
qemu-options.hx | 7 ++++---
2 files changed, 47 insertions(+), 5 deletions(-)
diff --git a/migration/file.c b/migration/file.c
index 0a65c43fdd..cf5b1bf365 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -6,6 +6,8 @@
*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
+#include "qapi/error.h"
#include "channel.h"
#include "file.h"
#include "migration.h"
@@ -13,14 +15,41 @@
#include "io/channel-util.h"
#include "trace.h"
-void file_start_outgoing_migration(MigrationState *s, const char *filename,
+#define OFFSET_OPTION ",offset="
+
+/* Remove the offset option from @filespec and return it in @offsetp. */
+
+static int file_parse_offset(char *filespec, uint64_t *offsetp, Error **errp)
+{
+ char *option = strstr(filespec, OFFSET_OPTION);
+ int ret;
+
+ if (option) {
+ *option = 0;
+ option += sizeof(OFFSET_OPTION) - 1;
+ ret = qemu_strtosz(option, NULL, offsetp);
+ if (ret) {
+ error_setg_errno(errp, -ret, "file URI has bad offset %s", option);
+ return -1;
+ }
+ }
+ return 0;
+}
+
+void file_start_outgoing_migration(MigrationState *s, const char *filespec,
Error **errp)
{
+ g_autofree char *filename = g_strdup(filespec);
g_autoptr(QIOChannelFile) fioc = NULL;
+ uint64_t offset = 0;
QIOChannel *ioc;
trace_migration_file_outgoing(filename);
+ if (file_parse_offset(filename, &offset, errp)) {
+ return;
+ }
+
fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC,
0600, errp);
if (!fioc) {
@@ -28,6 +57,9 @@ void file_start_outgoing_migration(MigrationState *s, const
char *filename,
}
ioc = QIO_CHANNEL(fioc);
+ if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+ return;
+ }
qio_channel_set_name(ioc, "migration-file-outgoing");
migration_channel_connect(s, ioc, NULL, NULL);
}
@@ -41,19 +73,28 @@ static gboolean file_accept_incoming_migration(QIOChannel
*ioc,
return G_SOURCE_REMOVE;
}
-void file_start_incoming_migration(const char *filename, Error **errp)
+void file_start_incoming_migration(const char *filespec, Error **errp)
{
+ g_autofree char *filename = g_strdup(filespec);
QIOChannelFile *fioc = NULL;
+ uint64_t offset = 0;
QIOChannel *ioc;
trace_migration_file_incoming(filename);
+ if (file_parse_offset(filename, &offset, errp)) {
+ return;
+ }
+
fioc = qio_channel_file_new_path(filename, O_RDONLY, 0, errp);
if (!fioc) {
return;
}
ioc = QIO_CHANNEL(fioc);
+ if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+ return;
+ }
qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming");
qio_channel_add_watch_full(ioc, G_IO_IN,
file_accept_incoming_migration,
diff --git a/qemu-options.hx b/qemu-options.hx
index 93e638c097..840b83d237 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4706,7 +4706,7 @@ DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \
" prepare for incoming migration, listen on\n" \
" specified protocol and socket address\n" \
"-incoming fd:fd\n" \
- "-incoming file:filename\n" \
+ "-incoming file:filename[,offset=offset]\n" \
"-incoming exec:cmdline\n" \
" accept incoming migration on given file descriptor\n" \
" or from given external command\n" \
@@ -4725,8 +4725,9 @@ SRST
``-incoming fd:fd``
Accept incoming migration from a given file descriptor.
-``-incoming file:filename``
- Accept incoming migration from a given file.
+``-incoming file:filename[,offset=offset]``
+ Accept incoming migration from a given file starting at offset.
+ offset allows the common size suffixes, or a 0x prefix, but not both.
``-incoming exec:cmdline``
Accept incoming migration as an output from specified external
--
2.41.0
- [PULL 11/11] migration: Unify and trace vmstate field_exists() checks, (continued)
- [PULL 11/11] migration: Unify and trace vmstate field_exists() checks, Juan Quintela, 2023/10/04
- [PULL 03/11] MAINTAINERS: Add entry for rdma migration, Juan Quintela, 2023/10/04
- [PULL 06/11] i386/a-b-bootblock: factor test memory addresses out into constants, Juan Quintela, 2023/10/04
- [PULL 08/11] s390x/a-b-bios: zero the first byte of each page on start, Juan Quintela, 2023/10/04
- [PULL 09/11] migration: file URI, Juan Quintela, 2023/10/04
[PULL 07/11] i386/a-b-bootblock: zero the first byte of each page on start, Juan Quintela, 2023/10/04
[PULL 10/11] migration: file URI offset,
Juan Quintela <=
Re: [PULL 00/11] Migration 20231004 patches, Stefan Hajnoczi, 2023/10/05