On Mon, 2014-03-17 at 14:49 +0100, Andreas Rohner wrote:
> >
> >> */
> >> struct nilfs_vdesc {
> >> __u64 vd_ino;
> >> @@ -873,9 +873,55 @@ struct nilfs_vdesc {
> >> __u64 vd_blocknr;
> >> __u64 vd_offset;
> >> __u32 vd_flags;
> >> - __u32 vd_pad;
> >> + /* vd_flags2 needed because of backwards compatibility */
> >
> > Completely, misunderstand comment. Usually, it keeps old fields for
> > backward compatibility. But this flag is new.
>
> I will rewrite the comment. I need vd_flags2 because I can't use
> vd_flags because of backwards compatibility.
>
> >> + __u32 vd_flags2;
What about vd_blk_state instead of vd_flags2?
> >> };
> >>
> >> +/* vdesc flags */
> >
> > To be honest, I misunderstand why such number of flags and why namely
> > such flags? Comments are really necessary.
> >
> >> +enum {
> >> + NILFS_VDESC_DATA,
> >> + NILFS_VDESC_NODE,
> >> + /* ... */
> >
> > What does it mean?
>
> NILFS_VDESC_DATA = 0 and NILFS_VDESC_NODE = 1. This represents the type
> of block. These two already existed, in the previous version, but they
> were not explicit. See "[Patch 4/4] nilfs-utils: add extra flags to
> nilfs_vdesc and update sui_nblocks":
>
> @@ -148,17 +149,19 @@ static int nilfs_acc_blocks_file(struct nilfs_file
> *file,
> - vdesc->vd_flags = 0; /* data */
> + nilfs_vdesc_set_data(vdesc);
> } else {
> vdesc->vd_vblocknr =
> le64_to_cpu(*(__le64 *)blk.b_binfo);
> - vdesc->vd_flags = 1; /* node */
> + nilfs_vdesc_set_node(vdesc);
> }
>
> >> +};
> >> +enum {
> >> + NILFS_VDESC_SNAPSHOT,
> >> + __NR_NILFS_VDESC_FIELDS,
> >> + /* ... */
> >
> > What does it mean?
I asked here about strange comment. What does it mean?
Moreover, I slightly confused by NILFS_VDESC_SNAPSHOT. Is it bit-based
flag? I mean NILFS_VDESC_SNAPSHOT = (1 << 0). Or am I incorrect?
Thanks,
Vyacheslav Dubeyko.
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