Xen devel - Apr 2012 - [PATCH 0/3] qemu-xen-traditional: xen_disk backports

Hi all,
this patch series is a set of xen_disk improvements backports from
upstream QEMU:

Stefano Stabellini (3):
      xen: handle backend deletion from xenstore
      xen_disk: use bdrv_aio_flush instead of bdrv_flush
      xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove
BLKIF_OP_WRITE_BARRIER

 hw/xen_backend.c |   17 +++++++++--------
 hw/xen_disk.c    |   27 ++++++++++++++++-----------
 2 files changed, 25 insertions(+), 19 deletions(-)

Cheers,

Stefano

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 hw/xen_backend.c |   17 +++++++++--------
 hw/xen_disk.c    |    4 ++++
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/hw/xen_backend.c b/hw/xen_backend.c
index 64dc93a..11e09fc 100644
--- a/hw/xen_backend.c
+++ b/hw/xen_backend.c
@@ -561,7 +561,7 @@ static void xenstore_update_be(char *watch, char *type, int
dom,
 			       struct XenDevOps *ops)
 {
     struct XenDevice *xendev;
-    char path[XEN_BUFSIZE], *dom0;
+    char path[XEN_BUFSIZE], *dom0, *bepath;
     unsigned int len, dev;
 
     dom0 = xs_get_domain_path(xenstore, 0);
@@ -577,15 +577,16 @@ static void xenstore_update_be(char *watch, char *type,
int dom,
     if (dev == -1)
 	return;
 
-    if (0) {
-	/* FIXME: detect devices being deleted from xenstore ... */
-	xen_be_del_xendev(dom, dev);
-    }
-
     xendev = xen_be_get_xendev(type, dom, dev, ops);
     if (xendev != NULL) {
-	xen_be_backend_changed(xendev, path);
-	xen_be_check_state(xendev);
+        bepath = xs_read(xenstore, 0, xendev->be, &len);
+        if (bepath == NULL) {
+            xen_be_del_xendev(dom, dev);
+        } else {
+            free(bepath);
+            xen_be_backend_changed(xendev, path);
+            xen_be_check_state(xendev);
+        }
     }
 }
 
diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 5db58ac..f9ef062 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -758,6 +758,10 @@ static int blk_free(struct XenDevice *xendev)
     struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
     struct ioreq *ioreq;
 
+    if (blkdev->bs || blkdev->sring) {
+        blk_disconnect(xendev);
+    }
+
     while (!LIST_EMPTY(&blkdev->freelist)) {
 	ioreq = LIST_FIRST(&blkdev->freelist);
         LIST_REMOVE(ioreq, list);
-- 
1.7.2.5

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 hw/xen_disk.c |   15 ++++++++-------
 1 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index f9ef062..900f456 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -382,8 +382,6 @@ static void qemu_aio_complete(void *opaque, int ret)
     ioreq->aio_inflight--;
     if (ioreq->aio_inflight > 0)
         return;
-    if (ioreq->postsync)
-	bdrv_flush(ioreq->blkdev->bs);
 
     ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
     ioreq_unmap(ioreq);
@@ -398,9 +396,10 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
     if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1)
 	goto err;
 
-    ioreq->aio_inflight++;
-    if (ioreq->presync)
-	bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
+    if (ioreq->presync) {
+        ioreq->aio_inflight++;
+        bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq);
+    }
 
     switch (ioreq->req.operation) {
     case BLKIF_OP_READ:
@@ -422,8 +421,10 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
 	/* unknown operation (shouldn''t happen -- parse catches this) */
 	goto err;
     }
-
-    qemu_aio_complete(ioreq, 0);
+    if (ioreq->postsync) {
+        ioreq->aio_inflight++;
+        bdrv_aio_flush(ioreq->blkdev->bs, qemu_aio_complete, ioreq);
+    }
 
     return 0;
 
-- 
1.7.2.5

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 hw/xen_disk.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 900f456..8181af9 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -181,13 +181,13 @@ static int ioreq_parse(struct ioreq *ioreq)
     case BLKIF_OP_READ:
 	ioreq->prot = PROT_WRITE; /* to memory */
 	break;
-    case BLKIF_OP_WRITE_BARRIER:
+    case BLKIF_OP_FLUSH_DISKCACHE:
         if (!ioreq->req.nr_segments) {
             ioreq->presync = 1;
             return 0;
         }
 	if (!syncwrite)
-	    ioreq->presync = ioreq->postsync = 1;
+        ioreq->postsync = 1;
 	/* fall through */
     case BLKIF_OP_WRITE:
 	ioreq->prot = PROT_READ; /* from memory */
@@ -333,7 +333,7 @@ static int ioreq_runio_qemu_sync(struct ioreq *ioreq)
 	}
 	break;
     case BLKIF_OP_WRITE:
-    case BLKIF_OP_WRITE_BARRIER:
+    case BLKIF_OP_FLUSH_DISKCACHE:
         if (!ioreq->req.nr_segments)
             break;
 	pos = ioreq->start;
@@ -669,7 +669,7 @@ static int blk_init(struct XenDevice *xendev)
 		  blkdev->file_size, blkdev->file_size >> 20);
 
     /* fill info */
-    xenstore_write_be_int(&blkdev->xendev, "feature-barrier",
have_barriers);
+    xenstore_write_be_int(&blkdev->xendev,
"feature-flush-cache", 1);
     xenstore_write_be_int(&blkdev->xendev, "info",           
info);
     xenstore_write_be_int(&blkdev->xendev, "sector-size",    
blkdev->file_blk);
     xenstore_write_be_int(&blkdev->xendev, "sectors",
-- 
1.7.2.5

Stefano Stabellini writes ("[Xen-devel] [PATCH 0/3] qemu-xen-traditional:
xen_disk backports"):
> Stefano Stabellini (3):
>       xen: handle backend deletion from xenstore
>       xen_disk: use bdrv_aio_flush instead of bdrv_flush
>       xen_disk: implement BLKIF_OP_FLUSH_DISKCACHE, remove
BLKIF_OP_WRITE_BARRIER
Thanks, they all look sensible, and you can put my ack on them:

Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

But can you please repost with some commit messages which contain a
reference to the corresponding upstream commit for each one ?  That
will make future archaeology much much easier.

Ian.