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Groups > linux.kernel > #1507334
| From | David Sterba <dsterba@suse.cz> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: Btrfs: fix free space tree bitmaps on big-endian systems |
| Date | 2016-10-24 17:50 +0200 |
| Message-ID | <svPFE-17R-29@gated-at.bofh.it> (permalink) |
| References | <svHRM-4qe-29@gated-at.bofh.it> <svHRM-4qe-27@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Oct 24, 2016 at 09:23:04AM +0200, Geert Uytterhoeven wrote:
> On Sat, Oct 15, 2016 at 2:46 AM, Linux Kernel Mailing List
> <linux-kernel@vger.kernel.org> wrote:
> > Web: https://git.kernel.org/torvalds/c/2fe1d55134fce05c17ea118a2e37a4af771887bc
> > Commit: 2fe1d55134fce05c17ea118a2e37a4af771887bc
>
> 520f16abf003952d in v4.7.10
> 1ff6341b5d92dd6b in v4.8.4
>
> > Parent: 08895a8b6b06ed2323cd97a36ee40a116b3db8ed
> > Refname: refs/heads/master
> > Author: Omar Sandoval <osandov@fb.com>
> > AuthorDate: Thu Sep 22 17:24:20 2016 -0700
> > Committer: David Sterba <dsterba@suse.com>
> > CommitDate: Mon Oct 3 18:52:14 2016 +0200
> >
> > Btrfs: fix free space tree bitmaps on big-endian systems
> >
> > In convert_free_space_to_{bitmaps,extents}(), we buffer the free space
> > bitmaps in memory and copy them directly to/from the extent buffers with
> > {read,write}_extent_buffer(). The extent buffer bitmap helpers use byte
> > granularity, which is equivalent to a little-endian bitmap. This means
> > that on big-endian systems, the in-memory bitmaps will be written to
> > disk byte-swapped. To fix this, use byte-granularity for the bitmaps in
> > memory.
>
> This change looks overly complex to me, and decreases performance.
We had to make it correct, performance is not an issue at the moment.
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Re: Btrfs: fix free space tree bitmaps on big-endian systems Geert Uytterhoeven <geert@linux-m68k.org> - 2016-10-24 09:30 +0200
Re: Btrfs: fix free space tree bitmaps on big-endian systems Omar Sandoval <osandov@osandov.com> - 2016-10-24 17:20 +0200
Re: Btrfs: fix free space tree bitmaps on big-endian systems Geert Uytterhoeven <geert@linux-m68k.org> - 2016-10-24 21:00 +0200
Re: Btrfs: fix free space tree bitmaps on big-endian systems David Sterba <dsterba@suse.cz> - 2016-10-24 17:50 +0200
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