Connections to ioemu have single_handler set, so they are closed as
soon as all images of a certain type are closed. This is wrong with
ioemu: All images that belong to the same domain are handled by the
same backend process (usually qemu-dm, but also tapdisk-ioemu for
domains without device model), regardless of the image type.
This patch checks for the same-domain condition for ioemu connections.
Signed-off-by: Kevin Wolf <kwolf@xxxxxxx>
blktapctrl: Fix too early close of pipes
Connections to ioemu have single_handler set, so they are closed as
soon as all images of a certain type are closed. This is wrong with
ioemu: All images that belong to the same domain are handled by the
same backend process (usually qemu-dm, but also tapdisk-ioemu for
domains without device model), regardless of the image type.
This patch checks for the same-domain condition for ioemu connections.
Signed-off-by: Kevin Wolf <kwolf@xxxxxxx>
Index: xen-unstable.hg/tools/blktap/drivers/blktapctrl.c
===================================================================
--- xen-unstable.hg.orig/tools/blktap/drivers/blktapctrl.c
+++ xen-unstable.hg/tools/blktap/drivers/blktapctrl.c
@@ -231,6 +231,24 @@ static void add_disktype(blkif_t *blkif,
entry->pprev = pprev;
}
+static int qemu_instance_has_disks(pid_t pid)
+{
+ int i;
+ int count = 0;
+ driver_list_entry_t *entry;
+
+ for (i = 0; i < MAX_DISK_TYPES; i++) {
+ entry = active_disks[i];
+ while (entry) {
+ if ((entry->blkif->tappid == pid) &&
dtypes[i]->use_ioemu)
+ count++;
+ entry = entry->next;
+ }
+ }
+
+ return (count != 0);
+}
+
static int del_disktype(blkif_t *blkif)
{
driver_list_entry_t *entry, **pprev;
@@ -255,6 +273,14 @@ static int del_disktype(blkif_t *blkif)
DPRINTF("DEL_DISKTYPE: Freeing entry\n");
free(entry);
+ /*
+ * When using ioemu, all disks of one VM are connected to the same
+ * qemu-dm instance. We may close the file handle only if there is
+ * no other disk left for this domain.
+ */
+ if (dtypes[type]->use_ioemu)
+ return !qemu_instance_has_disks(blkif->tappid);
+
/* Caller should close() if no single controller, or list is empty. */
return (!dtypes[type]->single_handler || (active_disks[type] == NULL));
}
@@ -721,6 +747,7 @@ static int unmap_blktapctrl(blkif_t *blk
}
if (del_disktype(blkif)) {
+ DPRINTF("Closing communication pipe to pid %d\n",
blkif->tappid);
close(blkif->fds[WRITE]);
close(blkif->fds[READ]);
}
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
Home