* Peter Xu (pet...@redhat.com) wrote:
> We will not allow failures to happen when sending data from destination
> to source via the return path. However it is possible that there can be
> errors along the way. This patch allows the migrate_send_rp_message()
> to return error when it happens, and further extended it to
> migrate_send_rp_req_pages().
>
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> migration/migration.c | 38 ++++++++++++++++++++++++++++++--------
> migration/migration.h | 2 +-
> 2 files changed, 31 insertions(+), 9 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index d0b9a86..9a0b5b0 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -195,17 +195,35 @@ static void deferred_incoming_migration(Error **errp)
> * Send a message on the return channel back to the source
> * of the migration.
> */
> -static void migrate_send_rp_message(MigrationIncomingState *mis,
> - enum mig_rp_message_type message_type,
> - uint16_t len, void *data)
> +static int migrate_send_rp_message(MigrationIncomingState *mis,
> + enum mig_rp_message_type message_type,
> + uint16_t len, void *data)
> {
> + int ret = 0;
> +
> trace_migrate_send_rp_message((int)message_type, len);
> qemu_mutex_lock(&mis->rp_mutex);
> +
> + /*
> + * It's possible that the file handle got lost due to network
> + * failures.
> + */
> + if (!mis->to_src_file) {
> + ret = -EIO;
> + goto error;
> + }
> +
Right, and this answers one of my questions from the previous patches.
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> qemu_put_be16(mis->to_src_file, (unsigned int)message_type);
> qemu_put_be16(mis->to_src_file, len);
> qemu_put_buffer(mis->to_src_file, data, len);
> qemu_fflush(mis->to_src_file);
> +
> + /* It's possible that qemu file got error during sending */
> + ret = qemu_file_get_error(mis->to_src_file);
> +
> +error:
> qemu_mutex_unlock(&mis->rp_mutex);
> + return ret;
> }
>
> /* Request a range of pages from the source VM at the given
> @@ -215,26 +233,30 @@ static void
> migrate_send_rp_message(MigrationIncomingState *mis,
> * Start: Address offset within the RB
> * Len: Length in bytes required - must be a multiple of pagesize
> */
> -void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char
> *rbname,
> - ram_addr_t start, size_t len)
> +int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char
> *rbname,
> + ram_addr_t start, size_t len)
> {
> uint8_t bufc[12 + 1 + 255]; /* start (8), len (4), rbname up to 256 */
> size_t msglen = 12; /* start + len */
> + int rbname_len;
> + enum mig_rp_message_type msg_type;
>
> *(uint64_t *)bufc = cpu_to_be64((uint64_t)start);
> *(uint32_t *)(bufc + 8) = cpu_to_be32((uint32_t)len);
>
> if (rbname) {
> - int rbname_len = strlen(rbname);
> + rbname_len = strlen(rbname);
> assert(rbname_len < 256);
>
> bufc[msglen++] = rbname_len;
> memcpy(bufc + msglen, rbname, rbname_len);
> msglen += rbname_len;
> - migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES_ID, msglen, bufc);
> + msg_type = MIG_RP_MSG_REQ_PAGES_ID;
> } else {
> - migrate_send_rp_message(mis, MIG_RP_MSG_REQ_PAGES, msglen, bufc);
> + msg_type = MIG_RP_MSG_REQ_PAGES;
> }
> +
> + return migrate_send_rp_message(mis, msg_type, msglen, bufc);
> }
>
> void qemu_start_incoming_migration(const char *uri, Error **errp)
> diff --git a/migration/migration.h b/migration/migration.h
> index 7aaab13..047872b 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -201,7 +201,7 @@ void migrate_send_rp_shut(MigrationIncomingState *mis,
> uint32_t value);
> void migrate_send_rp_pong(MigrationIncomingState *mis,
> uint32_t value);
> -void migrate_send_rp_req_pages(MigrationIncomingState *mis, const char*
> rbname,
> +int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char*
> rbname,
> ram_addr_t start, size_t len);
>
> #endif
> --
> 2.7.4
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
