Re: [Qemu-devel] [sheepdog] [PATCH v2 2/2] sheepdog: support user-defined redundancy option

[Liu Yuan <namei.unix@gmail.com>]

On Thu, Oct 31, 2013 at 04:41:05AM +0900, MORITA Kazutaka wrote:
> At Tue, 29 Oct 2013 16:25:52 +0800,
> Liu Yuan wrote:
> > 
> > Sheepdog support two kinds of redundancy, full replication and erasure coding.
> > 
> > # create a fully replicated vdi with x copies
> >  -o redundancy=x (1 <= x <= SD_MAX_COPIES)
> > 
> > # create a erasure coded vdi with x data strips and y parity strips
> >  -o redundancy=x:y (x must be one of {2,4,8,16} and 1 <= y < SD_EC_MAX_STRIP)
> > 
> > E.g, to convert a vdi into sheepdog vdi 'test' with 8:3 erasure coding scheme
> > 
> > $ qemu-img convert -o redundancy=8:3 linux-0.2.img sheepdog:test
> > 
> > Cc: Kevin Wolf <kwolf@redhat.com>
> > Cc: Stefan Hajnoczi <stefanha@redhat.com>
> > Signed-off-by: Liu Yuan <namei.unix@gmail.com>
> > ---
> >  block/sheepdog.c          |   78 ++++++++++++++++++++++++++++++++++++++++++++-
> >  include/block/block_int.h |    1 +
> >  2 files changed, 78 insertions(+), 1 deletion(-)
> > 
> > diff --git a/block/sheepdog.c b/block/sheepdog.c
> > index e66d2f8..bd7cfd6 100644
> > --- a/block/sheepdog.c
> > +++ b/block/sheepdog.c
> > @@ -91,6 +91,14 @@
> >  #define SD_NR_VDIS   (1U << 24)
> >  #define SD_DATA_OBJ_SIZE (UINT64_C(1) << 22)
> >  #define SD_MAX_VDI_SIZE (SD_DATA_OBJ_SIZE * MAX_DATA_OBJS)
> > +/*
> > + * For erasure coding, we use at most SD_EC_MAX_STRIP for data strips and
> > + * (SD_EC_MAX_STRIP - 1) for parity strips
> > + *
> > + * SD_MAX_COPIES is sum of number of dats trips and parity strips.
> > + */
> > +#define SD_EC_MAX_STRIP 16
> > +#define SD_MAX_COPIES (SD_EC_MAX_STRIP * 2 - 1)
> >  
> >  #define SD_INODE_SIZE (sizeof(SheepdogInode))
> >  #define CURRENT_VDI_ID 0
> > @@ -1446,6 +1454,65 @@ out:
> >      return ret;
> >  }
> >  
> > +static int64_t is_numeric(const char *s)
> > +{
> > +    char *end;
> > +    return strtosz_suffix(s, &end, STRTOSZ_DEFSUFFIX_B);
> > +}
> 
> I think the type of the return value should be bool.
> 

Actually I copied from cvtnum() it returns negative to indicate errors. Either
way I found a bug in this version. I'll try another approach to test if it is
numbers in next version.

Thanks
Yuan