Re: [Qemu-devel] [PATCH 19/27] block/parallels: implement incorrect close detection

[Roman Kagan]

On Tue, Mar 10, 2015 at 05:44:19PM +0300, Denis V. Lunev wrote:
> On 10/03/15 17:38, Roman Kagan wrote:
> >On Tue, Mar 10, 2015 at 11:51:13AM +0300, Denis V. Lunev wrote:
> >>The software driver must set inuse field in Parallels header to
> >>0x746F6E59 when the image is opened in read-write mode. The presence of
> >>this magic in the header on open forces image consistency check.
> >>
> >>There is an unfortunate trick here. We can not check for inuse in
> >>parallels_check as this will happen too late. It is possible to do
> >>that for simple check, but during the fix this would always report
> >>an error as the image was opened in BDRV_O_RDWR mode. Thus we save
> >>the flag in BDRVParallelsState for this.
> >>
> >>On the other hand, nothing should be done to clear inuse in
> >>parallels_check. Generic close will do the job right.
> >>
> >>Signed-off-by: Denis V. Lunev <address@hidden>
> >>CC: Roman Kagan <address@hidden>
> >>CC: Kevin Wolf <address@hidden>
> >>CC: Stefan Hajnoczi <address@hidden>
> >>---
> >>  block/parallels.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 50 insertions(+)
> >>@@ -462,6 +487,25 @@ static int parallels_open(BlockDriverState *bs, QDict 
> >>*options, int flags,
> >>      }
> >>      s->bat_bitmap = (uint32_t *)(s->header + 1);
> >>+    if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
> >>+        /* Image was not closed correctly. The check is mandatory */
> >>+        s->header_unclean = true;
> >>+        if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
> >>+            error_setg(errp, "parallels: Image was not closed correctly; "
> >>+                       "cannot be opened read/write");
> >>+            ret = -EACCES;
> >-EBUSY?
> >
> >Otherwise looks ok.
> >
> >Roman.
> error code is the same as one in qcow2

OK then

Reviewed-by: Roman Kagan <address@hidden>

Roman.