During migration, QEMU uses fsync()/fdatasync() on the open file descriptor for read-write block devices to flush data just before stopping the VM.
However, fsync() on a scsi-generic device returns -EINVAL which causes the migration to fail. This patch skips flushing data in case of an SG device, since submitting SCSI commands directly via an SG character device (e.g. /dev/sg0) bypasses the page cache completely, anyway. Remove the bdrv_is_sg() test from iscsi_co_flush() since this is now redundant (we flush the underlying protocol at the end of bdrv_co_flush() which, with this patch, we never reach). Signed-off-by: Dimitris Aragiorgis <dim...@arrikto.com> --- block/io.c | 2 +- block/iscsi.c | 4 ---- 2 files changed, 1 insertion(+), 5 deletions(-) diff --git a/block/io.c b/block/io.c index 1ce62c4..d248a4d 100644 --- a/block/io.c +++ b/block/io.c @@ -2231,7 +2231,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs) { int ret; - if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) { + if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || bdrv_is_sg(bs)) { return 0; } diff --git a/block/iscsi.c b/block/iscsi.c index 502a81f..965978b 100644 --- a/block/iscsi.c +++ b/block/iscsi.c @@ -627,10 +627,6 @@ static int coroutine_fn iscsi_co_flush(BlockDriverState *bs) IscsiLun *iscsilun = bs->opaque; struct IscsiTask iTask; - if (bdrv_is_sg(bs)) { - return 0; - } - if (!iscsilun->force_next_flush) { return 0; } -- 1.7.10.4