From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 9 Aug 2017 16:02:11 +0000 (+0100)
Subject: IDE: Do not flush empty CDROM drives
X-Git-Tag: v2.10.0-rc3~16^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4da97120d51a4383aa96d741a2b837f8c4bbcd0b;p=thirdparty%2Fqemu.git

IDE: Do not flush empty CDROM drives

The block backend changed in a way that flushing empty CDROM drives now
crashes.  Amend IDE to avoid doing so until the root problem can be
addressed for 2.11.

Original patch by John Snow <jsnow@redhat.com>.

Reported-by: Kieron Shorrock <kshorrock@paloaltonetworks.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20170809160212.29976-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---

diff --git a/hw/ide/core.c b/hw/ide/core.c
index 0b48b64d3ae..bea39536b05 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1063,7 +1063,15 @@ static void ide_flush_cache(IDEState *s)
     s->status |= BUSY_STAT;
     ide_set_retry(s);
     block_acct_start(blk_get_stats(s->blk), &s->acct, 0, BLOCK_ACCT_FLUSH);
-    s->pio_aiocb = blk_aio_flush(s->blk, ide_flush_cb, s);
+
+    if (blk_bs(s->blk)) {
+        s->pio_aiocb = blk_aio_flush(s->blk, ide_flush_cb, s);
+    } else {
+        /* XXX blk_aio_flush() crashes when blk_bs(blk) is NULL, remove this
+         * temporary workaround when blk_aio_*() functions handle NULL blk_bs.
+         */
+        ide_flush_cb(s, 0);
+    }
 }
 
 static void ide_cfata_metadata_inquiry(IDEState *s)