Re: [Qemu-devel] [PATCH 2/2] xen: Don't peek behind the BlockDriverState abstraction

[Stefano Stabellini]

On Wed, 6 Jun 2012, Markus Armbruster wrote:
> Stefano Stabellini <address@hidden> writes:
> > On Tue, 5 Jun 2012, Markus Armbruster wrote:
> >> First offender is xen_config_dev_blk()'s use of disk->bdrv->filename.
> >> Get the filename from disk->opts instead.  Same result, except for
> >> snapshots: there, we now get the filename specified by the user
> >> instead of the name of the temporary image created by bdrv_open().
> >> Should be an improvement.
> >> 
> >> Second offender is blk_init()'s use of blkdev->bs->drv->format_name.
> >> Simply use the appropriate interface to get the format name.
> >> 
> >> Signed-off-by: Markus Armbruster <address@hidden>
> >> ---
> >>  hw/xen_devconfig.c |    6 +++---
> >>  hw/xen_disk.c      |    5 +++--
> >>  2 files changed, 6 insertions(+), 5 deletions(-)
> >> 
> >> diff --git a/hw/xen_devconfig.c b/hw/xen_devconfig.c
> >> index 7b7b0a2..0928613 100644
> >> --- a/hw/xen_devconfig.c
> >> +++ b/hw/xen_devconfig.c
> >> @@ -1,6 +1,5 @@
> >>  #include "xen_backend.h"
> >>  #include "blockdev.h"
> >> -#include "block_int.h" /* XXX */
> >>  
> >>  /* ------------------------------------------------------------- */
> >>  
> >> @@ -99,10 +98,11 @@ int xen_config_dev_blk(DriveInfo *disk)
> >>      int cdrom = disk->media_cd;
> >>      const char *devtype = cdrom ? "cdrom" : "disk";
> >>      const char *mode    = cdrom ? "r"     : "w";
> >> +    const char *filename = qemu_opt_get(disk->opts, "file");
> >>  
> >>      snprintf(device_name, sizeof(device_name), "xvd%c", 'a' + disk->unit);
> >>      xen_be_printf(NULL, 1, "config disk %d [%s]: %s\n",
> >> -                  disk->unit, device_name, disk->bdrv->filename);
> >> +                  disk->unit, device_name, filename);
> >>      xen_config_dev_dirs("vbd", "qdisk", vdev, fe, be, sizeof(fe));
> >>  
> >>      /* frontend */
> >> @@ -112,7 +112,7 @@ int xen_config_dev_blk(DriveInfo *disk)
> >>      /* backend */
> >>      xenstore_write_str(be, "dev",             device_name);
> >>      xenstore_write_str(be, "type",            "file");
> >> -    xenstore_write_str(be, "params",          disk->bdrv->filename);
> >> +    xenstore_write_str(be, "params",          filename);
> >>      xenstore_write_str(be, "mode",            mode);
> >>  
> >>      /* common stuff */
> >> diff --git a/hw/xen_disk.c b/hw/xen_disk.c
> >> index 07594bc..c73b71e 100644
> >> --- a/hw/xen_disk.c
> >> +++ b/hw/xen_disk.c
> >> @@ -40,7 +40,6 @@
> >>  #include <xen/io/xenbus.h>
> >>  
> >>  #include "hw.h"
> >> -#include "block_int.h"
> >>  #include "qemu-char.h"
> >>  #include "xen_blkif.h"
> >>  #include "xen_backend.h"
> >> @@ -554,6 +553,7 @@ static int blk_init(struct XenDevice *xendev)
> >>  {
> >>      struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, 
> >> xendev);
> >>      int index, qflags, info = 0;
> >> +    char fmt_name[128];
> >>  
> >>      /* read xenstore entries */
> >>      if (blkdev->params == NULL) {
> >> @@ -634,9 +634,10 @@ static int blk_init(struct XenDevice *xendev)
> >>      blkdev->file_blk  = BLOCK_SIZE;
> >>      blkdev->file_size = bdrv_getlength(blkdev->bs);
> >>      if (blkdev->file_size < 0) {
> >> +        bdrv_get_format(blkdev->bs, fmt_name, sizeof(fmt_name));
> >>          xen_be_printf(&blkdev->xendev, 1, "bdrv_getlength: %d (%s) | drv 
> >> %s\n",
> >>                        (int)blkdev->file_size, 
> >> strerror(-blkdev->file_size),
> >> -                      blkdev->bs->drv ? blkdev->bs->drv->format_name : 
> >> "-");
> >> +                      fmt_name[0] ? fmt_name : "-");
> >>          blkdev->file_size = 0;
> >>      }
> >
> > You might as well move fmt_name here because it is only used if
> > blkdev->file_size < 0.
> 
> Matter of taste, and you're the maintainer.  Want me to respin?
 
Yes, please :-)