On Tue, Mar 25, 2025 at 10:06:55AM +0000, Matthew Wilcox wrote: > On Mon, Mar 24, 2025 at 08:47:05AM +0800, Nanzhe Zhao wrote: > > Knowing that the F2FS community is currently heavily invested in the > > folio support effort, I wanted to also bring up some observations and > > questions regarding folio support in F2FS garbage collection. > > Specifically, I'm concerned about the challenge of allocating > > high-order folios due to non-contiguous index ranges during the GC > > process. I've initiated a discussion about this issue on the f2fs > > mailing list in an email > > thread.[https://lore.kernel.org/linux-f2fs-devel/CAMLCH1F8niz3qifu9pt6C3yLhonadD=feaptwkhcard8fpj...@mail.gmail.com/T/#u] > > I would be grateful if you and other developers could take a look and > > share your thoughts. > > Sorry, I'm at LSFMM this week and don't have time to dig into this. > I hope you saw my recent email about folios: > > https://lore.kernel.org/linux-f2fs-devel/z9rr2ubks9caf...@casper.infradead.org/ > > The fundamental problem is that f2fs has no per-block data structure. In > ext4, that's struct buffer_head. For XFS, it's struct iomap_folio_state. > For btrfs, it's struct btrfs_subpage and for bcachefs, it's struct > bch_folio. > > Either f2fs needs to grow its own, or it needs to share iomap with > XFS. Both options are a lot of work; iomap doesn't support all the > functionality that f2fs needs. But btrfs is looking to move to using > iomap and it has some of the same needs that f2fs has, so perhaps you > can help each other.
I think there are two reasonable projects you could undertake which would be generally helpful. One is that you could add fsverity support to XFS. You'd want to coordinate with the XFS developers as a number of them have Strongly Held Opinions on how this should be done. There may even be prototype code; I haven't been following closely. The other is that you could help out with the ext4 large folio conversion. There are already patches for this: https://lore.kernel.org/linux-fsdevel/20241125114419.903270-1-yi.zh...@huaweicloud.com/ As the cover letter says, "with the exception of fsverity, fscrypt, and data=journal mode." So you could perhaps apply this patch series (patch 1 is now obsolete), and try to make fsverity work. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
