From: Jan Kara <jack@suse.cz>
To: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Jan Kara <jack@suse.com>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
"Fabio M . De Francesco" <fmdefrancesco@gmail.com>
Subject: Re: [PATCH 02/10] ext2: Convert ext2_check_page to ext2_check_folio
Date: Tue, 3 Oct 2023 12:52:24 +0200 [thread overview]
Message-ID: <20231003105224.3j47fjxpiudwvupn@quack3> (raw)
In-Reply-To: <20231003104017.ohuyl3fv2mobif5u@quack3>
On Tue 03-10-23 12:40:17, Jan Kara wrote:
> On Thu 21-09-23 21:07:39, Matthew Wilcox (Oracle) wrote:
> > Support in this function for large folios is limited to supporting
> > filesystems with block size > PAGE_SIZE. This new functionality will only
> > be supported on machines without HIGHMEM, so the problem of kmap_local
> > only being able to map a single page in the folio can be ignored.
> > We will not use large folios for ext2 directories on HIGHMEM machines.
>
> OK, but can we perhaps enforce this with some checks & error messages
> instead of a silent failure? Like:
>
> #ifdef CONFIG_HIGHMEM
> if (sb->s_blocksize > PAGE_SIZE)
> bail with error
> #endif
>
> somewhere in ext2_fill_super()? Or maybe force allocation of lowmem pages
> when blocksize > PAGE_SIZE?
>
> > @@ -195,9 +195,9 @@ static void *ext2_get_page(struct inode *dir, unsigned long n,
> >
> > if (IS_ERR(folio))
> > return ERR_CAST(folio);
> > - page_addr = kmap_local_folio(folio, n & (folio_nr_pages(folio) - 1));
> > + page_addr = kmap_local_folio(folio, 0);
Oh, and I think this change breaks the code whenever we get back higher
order folio because the page_addr we get back is not for the page index
'n'.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2023-10-03 10:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-21 20:07 [PATCH 01/10] highmem: Add folio_release_kmap() Matthew Wilcox (Oracle)
2023-09-21 20:07 ` [PATCH 02/10] ext2: Convert ext2_check_page to ext2_check_folio Matthew Wilcox (Oracle)
2023-10-03 10:40 ` Jan Kara
2023-10-03 10:52 ` Jan Kara [this message]
2023-10-05 18:27 ` Matthew Wilcox
2023-10-03 11:02 ` Jan Kara
2023-09-21 20:07 ` [PATCH 03/10] ext2: Add ext2_get_folio() Matthew Wilcox (Oracle)
2023-09-21 20:07 ` [PATCH 04/10] ext2: Convert ext2_readdir to use a folio Matthew Wilcox (Oracle)
2023-09-21 20:07 ` [PATCH 05/10] ext2: Convert ext2_add_link() " Matthew Wilcox (Oracle)
2023-09-21 20:07 ` [PATCH 06/10] ext2: Convert ext2_empty_dir() " Matthew Wilcox (Oracle)
2023-09-21 20:07 ` [PATCH 07/10] ext2: Handle large block size directories in ext2_delete_entry() Matthew Wilcox (Oracle)
2023-10-25 18:17 ` Jan Kara
2023-09-21 20:07 ` [PATCH 08/10] ext2: Convert ext2_unlink() and ext2_rename() to use folios Matthew Wilcox (Oracle)
2023-10-25 18:20 ` Jan Kara
2023-09-21 20:07 ` [PATCH 09/10] ext2: Convert ext2_make_empty() to use a folio Matthew Wilcox (Oracle)
2023-10-03 10:41 ` [PATCH 01/10] highmem: Add folio_release_kmap() Jan Kara
2023-10-03 11:55 ` Matthew Wilcox
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