Re: [Qemu-block] [PATCH 1/4] Fix migration in case of scsi-generic

2015-05-08 Thread Paolo Bonzini 


On 08/05/2015 13:38, Dimitris Aragiorgis wrote:
 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.

Good catch!  The patch is correct, but please remove the same test from
iscsi_co_flush (in block/iscsi.c) because it's now duplicate.

Thanks,

Paolo

 Signed-off-by: Dimitris Aragiorgis dim...@arrikto.com
 ---
  block/io.c |2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
 
 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;
  }

[Qemu-block] [PATCH 1/4] Fix migration in case of scsi-generic

2015-05-08 Thread Dimitris Aragiorgis 
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.

Signed-off-by: Dimitris Aragiorgis dim...@arrikto.com
---
 block/io.c |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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;
 }
 
-- 
1.7.10.4