Re: [PATCH v2 00/19] btrfs: add read-only support for subpage sector size

Neal Gompa
2020-09-17T00:23:01Z

On Wed, Sep 16, 2020 at 8:03 PM Qu Wenruo <wqu@suse.com> wrote:
>
>
>
> On 2020/9/17 上午12:18, Neal Gompa wrote:
> > On Tue, Sep 15, 2020 at 1:36 AM Qu Wenruo <wqu@suse.com> wrote:
> >>
> >> Patches can be fetched from github:
> >> https://github.com/adam900710/linux/tree/subpage
> >>
> >> Currently btrfs only allows to mount fs with sectorsize == PAGE_SIZE.
> >>
> >> That means, for 64K page size system, they can only use 64K sector size
> >> fs.
> >> This brings a big compatible problem for btrfs.
> >>
> >> This patch is going to slightly solve the problem by, allowing 64K
> >> system to mount 4K sectorsize fs in read-only mode.
> >>
> >> The main objective here, is to remove the blockage in the code base, and
> >> pave the road to full RW mount support.
> >>
> >
> > Is there a reason we don't include a patch in here to just hardwire
> > the block size to 4K going forward?
> >
>
> Did you mean to make 4K sector size the hard requirement?
>
> That would make existing 64K sector size fs unable to be mounted then.
>

I mean, make the 64K variant a legacy one and force 4K for all new
filesystems. That then simplifies this work to making it mountable and
usable as a legacy filesystem format.

I guess that would be an incompat flag, no?

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