On 8/27/20 3:58 PM, Daniel P. Berrangé wrote: > On Thu, Jul 09, 2020 at 04:26:42PM +0300, Denis V. Lunev wrote: >> Right now bdrv_fclose() is just calling bdrv_flush(). >> >> The problem is that migration code is working inefficiently from block >> layer terms and are frequently called for very small pieces of >> unaligned data. Block layer is capable to work this way, but this is very >> slow. >> >> This patch is a preparation for the introduction of the intermediate >> buffer at block driver state. It would be beneficial to separate >> conventional bdrv_flush() from closing QEMU file from migration code. >> >> The patch also forces bdrv_finalize_vmstate() operation inside >> synchronous blk_save_vmstate() operation. This helper is used from >> qemu-io only. >> >> Signed-off-by: Denis V. Lunev <[email protected]> >> Reviewed-by: Vladimir Sementsov-Ogievskiy <[email protected]> >> CC: Kevin Wolf <[email protected]> >> CC: Max Reitz <[email protected]> >> CC: Stefan Hajnoczi <[email protected]> >> CC: Fam Zheng <[email protected]> >> CC: Juan Quintela <[email protected]> >> CC: "Dr. David Alan Gilbert" <[email protected]> >> CC: Denis Plotnikov <[email protected]> >> --- >> block/block-backend.c | 6 +++++- >> block/io.c | 15 +++++++++++++++ >> include/block/block.h | 5 +++++ >> migration/savevm.c | 4 ++++ >> 4 files changed, 29 insertions(+), 1 deletion(-) >> diff --git a/migration/savevm.c b/migration/savevm.c >> index 45c9dd9d8a..d8a94e312c 100644 >> --- a/migration/savevm.c >> +++ b/migration/savevm.c >> @@ -150,6 +150,10 @@ static ssize_t block_get_buffer(void *opaque, uint8_t >> *buf, int64_t pos, >> >> static int bdrv_fclose(void *opaque, Error **errp) >> { >> + int err = bdrv_finalize_vmstate(opaque); >> + if (err < 0) { >> + return err; > This is returning an error without having populating 'errp' which means > the caller will be missing error diagnosis
but this behaves exactly like the branch below, bdrv_flush() could return error too and errp is not filled in the same way. Den >> + } >> return bdrv_flush(opaque); >> } > Regards, > Daniel
