Re: [PATCH v2 9/9] pack-objects: improve partial packfile reuse

From: Christian Couder <christian.couder@gmail.com>
Date: Oct 19, 2019, 19:20 UTC
Message-ID: <CAP8UFD2rsZj3=KoPCEWw2sTXFhNkynrJLeAGWK2vEbD5GU8chA@mail.gmail.com>
In-Reply-To: <6e4ad9bb-20d7-4ae5-8768-326f5c455c3c@iee.email>

Hi Philip,

On Sat, Oct 19, 2019 at 5:30 PM Philip Oakley <philipoakley@iee.email> wrote:

> On 19/10/2019 11:35, Christian Couder wrote:

Show 8 quoted lines

> > +static void write_reused_pack_one(size_t pos, struct hashfile *out,
> > +                               struct pack_window **w_curs)
> > +{
> > +     off_t offset, next, cur;
> > +     enum object_type type;
> > +     unsigned long size;
>
> Is this a mem_sized size or a counter for less that 4GiB items?

What I can see is that `&size` is passed as the last argument to unpack_object_header() below. And unpack_object_header() is defined in packfile.h like this:

int unpack_object_header(struct packed_git *, struct pack_window **, off_t *, unsigned long *);

since at least 336226c259 (packfile.h: drop extern from function declarations, 2019-04-05)

So fixing this, if it needs to be fixed, should probably be part of a separate topic fixing unpack_object_header().

Show 12 quoted lines

> > +
> > +     offset = reuse_packfile->revindex[pos].offset;
> > +     next = reuse_packfile->revindex[pos + 1].offset;
> >
> > -     if (reuse_packfile_offset < 0)
> > -             reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
> > +     record_reused_object(offset, offset - hashfile_total(out));
> >
> > -     total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
> > +     cur = offset;
> > +     type = unpack_object_header(reuse_packfile, w_curs, &cur, &size);
> > +     assert(type >= 0);

Show 11 quoted lines

> > +static void try_partial_reuse(struct bitmap_index *bitmap_git,
> > +                           size_t pos,
> > +                           struct bitmap *reuse,
> > +                           struct pack_window **w_curs)
> >   {
> > +     struct revindex_entry *revidx;
> > +     off_t offset;
> > +     enum object_type type;
> > +     unsigned long size;
>
> Is this mem_sized or a <4GiB size?

Again this `size` variable is passed as the last argument to unpack_object_header() below.

...

> Apologies if these are dumb queries..

I think it's a valid concern, so it's certainly ok for you to ask these questions.