Re: [PATCH 0/8] Convert reiserfs from b_page to b_folio

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

On venerdì 16 dicembre 2022 21:53:39 CET Matthew Wilcox (Oracle) wrote:
> These patches apply on top of
> https://lore.kernel.org/linux-fsdevel/20221215214402.3522366-1-willy@infradead
> .org/
> 
> The non-trivial ones mostly revolve around uses of kmap()/kmap_atomic(),
> so review from the experts on those would be welcome.

I took a quick look at your conversions and they made me recall that months 
ago you converted to kmap_local_folio() a previous conversion from kmap() to 
kmap_local_page() in ext2_get_page(): commit 37ce0b319b287 ("ext2: Use a folio 
in ext2_get_page()").

So I just saw kmap_local_folio again. Unfortunately, because of my 
inexperience,  I'm not able to see why we should prefer the use of this 
function instead of kmap_local_page().

Can you please tell me why and when we should prefer kmap_local_folio() in 
those cases too where kmap_local_page() can work properly? I'm asking because 
these days I'm converting other *_get_page() from kmap() (including the series 
to fs/ufs that I sent today).

> If these all look
> good to people, I can pass them off to Andrew for the 6.3 merge window.
> 
> Running xfstests against reiserfs gives me 313/701 failures before and
> after this set of patches.

It has happened several times to me too. Some patches of mine have failures 
from xfstests whose amounts and types don't change with or without my changes.

Several of them have already been merged. I guess that if they don't add 
further failures everything is alright.

However, something is broken for sure... xfstests or the filesystems? :-/ 

Thanks,

Fabio

> I don't have a huge amount of confidence
> that we're really getting good coverage from that test run!
> 
> Matthew Wilcox (Oracle) (8):
>   reiserfs: use b_folio instead of b_page in some obvious cases
>   reiserfs: use kmap_local_folio() in _get_block_create_0()
>   reiserfs: Convert direct2indirect() to call folio_zero_range()
>   reiserfs: Convert reiserfs_delete_item() to use kmap_local_folio()
>   reiserfs: Convert do_journal_end() to use kmap_local_folio()
>   reiserfs: Convert map_block_for_writepage() to use kmap_local_folio()
>   reiserfs: Convert convert_tail_for_hole() to use folios
>   reiserfs: Use flush_dcache_folio() in reiserfs_quota_write()
> 
>  fs/reiserfs/inode.c           | 73 +++++++++++++++++------------------
>  fs/reiserfs/journal.c         | 12 +++---
>  fs/reiserfs/prints.c          |  4 +-
>  fs/reiserfs/stree.c           |  9 +++--
>  fs/reiserfs/super.c           |  2 +-
>  fs/reiserfs/tail_conversion.c | 19 ++++-----
>  6 files changed, 59 insertions(+), 60 deletions(-)
> 
> --
> 2.35.1