Re: [Qemu-devel] [PATCH 18/27] block/parallels: implement parallels_check method of block driver

[Denis V. Lunev]

On 10/03/15 17:24, Roman Kagan wrote:
> On Tue, Mar 10, 2015 at 11:51:12AM +0300, Denis V. Lunev wrote:
> > The check is very simple at the moment. It calculates necessary stats
> > and fix only the following errors:
> > - space leak at the end of the image. This would happens due to
> >    preallocation
> > - clusters outside the image are zeroed. Nothing else could be done here
> >
> > 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 | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 82 insertions(+)
> >
> > diff --git a/block/parallels.c b/block/parallels.c
> > index 65f6418..e5b475e 100644
> > --- a/block/parallels.c
> > +++ b/block/parallels.c
> > @@ -228,6 +228,87 @@ fail:
> >       return ret;
> >   }
> >   
> > +
> > +static int parallels_check(BlockDriverState *bs, BdrvCheckResult *res,
> > +                           BdrvCheckMode fix)
> > +{
> > +    BDRVParallelsState *s = bs->opaque;
> > +    int64_t size, prev_off, high_off;
> > +    int ret;
> > +    uint32_t i;
> > +    bool flush_bat = false;
> > +    int cluster_size = s->tracks << BDRV_SECTOR_BITS;
> > +
> > +    size = bdrv_getlength(bs->file);
> > +    if (size < 0) {
> > +        res->check_errors++;
> > +        return size;
> > +    }
> > +
> > +    res->bfi.total_clusters = s->bat_size;
> > +    res->bfi.compressed_clusters = 0; /* compression is not supported */
> > +
> > +    high_off = 0;
> > +    prev_off = 0;
> > +    for (i = 0; i < s->bat_size; i++) {
> > +        int64_t off = bat2sect(s, i) << BDRV_SECTOR_BITS;
> > +        if (off == 0)
> > +            continue;
> If you don't update prev_off here you can get fragmentation stats wrong
> (dunno how important it is)

ok. by the way, I have missed braces here...

> > +
> > +        /* cluster outside the image */
> > +        if (off > size) {
> > +            fprintf(stderr, "%s cluster %u is outside image\n",
> > +                    fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
> > +            res->corruptions++;
> > +            if (fix & BDRV_FIX_ERRORS) {
> > +                s->bat_bitmap[i] = 0;
> > +                res->corruptions_fixed++;
> > +                flush_bat = true;
> > +                continue;
> > +            }
> Ditto
>
> Roman.