linux-erofs.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>,
	"Darrick J. Wong" <djwong@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Joseph Qi <joseph.qi@linux.alibaba.com>,
	Liu Bo <bo.liu@linux.alibaba.com>,
	linux-fsdevel@vger.kernel.org,
	Gao Xiang <hsiangkao@linux.alibaba.com>,
	Liu Jiang <gerry@linux.alibaba.com>,
	linux-erofs@lists.ozlabs.org
Subject: Re: [PATCH 1/2] iomap: support tail packing inline read
Date: Fri, 16 Jul 2021 14:47:35 +0100	[thread overview]
Message-ID: <YPGN97vWokqkWSZn@casper.infradead.org> (raw)
In-Reply-To: <YPFPDS5ktWJEUKTo@infradead.org>

On Fri, Jul 16, 2021 at 10:19:09AM +0100, Christoph Hellwig wrote:
>  static void
>  iomap_read_inline_data(struct inode *inode, struct page *page,
> -		struct iomap *iomap)
> +		struct iomap *iomap, loff_t pos, unsigned int size)
>  {
> -	size_t size = i_size_read(inode);
> +	unsigned int block_aligned_size = round_up(size, i_blocksize(inode));
> +	unsigned int poff = offset_in_page(pos);
>  	void *addr;
>  
> -	if (PageUptodate(page))
> -		return;
> -
> -	BUG_ON(page_has_private(page));
> -	BUG_ON(page->index);
> +	/* make sure that inline_data doesn't cross page boundary */
>  	BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
> +	BUG_ON(size != i_size_read(inode) - pos);
>  
>  	addr = kmap_atomic(page);
> -	memcpy(addr, iomap->inline_data, size);
> -	memset(addr + size, 0, PAGE_SIZE - size);
> +	memcpy(addr + poff, iomap->inline_data - iomap->offset + pos, size);
> +	memset(addr + poff + size, 0, block_aligned_size - size);
>  	kunmap_atomic(addr);
> -	SetPageUptodate(page);
> +
> +	iomap_set_range_uptodate(page, poff, block_aligned_size);
>  }

This should be relatively straightforward to port to folios.
I think it looks something like this ...

@@ -211,23 +211,18 @@ struct iomap_readpage_ctx {
 };

 static void iomap_read_inline_data(struct inode *inode, struct folio *folio,
-               struct iomap *iomap)
+               struct iomap *iomap, loff_t pos, size_t size)
 {
-       size_t size = i_size_read(inode);
        void *addr;
+       size_t offset = offset_in_folio(folio, pos);

-       if (folio_test_uptodate(folio))
-               return;
+       BUG_ON(size != i_size_read(inode) - pos);

-       BUG_ON(folio->index);
-       BUG_ON(folio_multi(folio));
-       BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
-
-       addr = kmap_local_folio(folio, 0);
+       addr = kmap_local_folio(folio, offset);
        memcpy(addr, iomap->inline_data, size);
        memset(addr + size, 0, PAGE_SIZE - size);
        kunmap_local(addr);
-       folio_mark_uptodate(folio);
+       iomap_set_range_uptodate(folio, to_iomap_page(folio), pos, size);
 }

> -	if (iomap->type == IOMAP_INLINE) {
> -		WARN_ON_ONCE(pos);
> -		iomap_read_inline_data(inode, page, iomap);
> -		return PAGE_SIZE;
> -	}
> +	if (iomap->type == IOMAP_INLINE && !pos)
> +		WARN_ON_ONCE(to_iomap_page(page) != NULL);
> +	else
> +		iop = iomap_page_create(inode, page);

This WARN_ON doesn't make sense to me.  If a file contains bytes 0-2047
that are !INLINE and then bytes 2048-2050 that are INLINE, we're going
to trigger it.  Perhaps just make this:

	if (iomap->type != IOMAP_INLINE || pos)
		iop = iomap_page_create(inode, page);


  parent reply	other threads:[~2021-07-16 13:48 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16  5:07 [PATCH 0/2] erofs: iomap support for tailpacking cases Gao Xiang
2021-07-16  5:07 ` [PATCH 1/2] iomap: support tail packing inline read Gao Xiang
2021-07-16  9:19   ` Christoph Hellwig
2021-07-16  9:46     ` Gao Xiang
2021-07-16 13:47     ` Matthew Wilcox [this message]
2021-07-16 14:38       ` Matthew Wilcox
2021-07-16 13:02   ` Matthew Wilcox
2021-07-16 13:56     ` Gao Xiang
2021-07-16 14:44       ` Matthew Wilcox
2021-07-16 15:03         ` Gao Xiang
2021-07-16 15:53           ` Andreas Grünbacher
2021-07-17 13:38             ` Gao Xiang
2021-07-17 15:01               ` Matthew Wilcox
2021-07-17 15:15                 ` Gao Xiang
2021-07-17 18:40                   ` Matthew Wilcox
2021-07-19 11:19                     ` Christoph Hellwig
2021-07-19 13:45                       ` Gao Xiang
2021-07-19 11:15               ` Christoph Hellwig
2021-07-19 13:31                 ` Gao Xiang
2021-07-16  5:07 ` [PATCH 2/2] erofs: convert all uncompressed cases to iomap Gao Xiang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YPGN97vWokqkWSZn@casper.infradead.org \
    --to=willy@infradead.org \
    --cc=agruenba@redhat.com \
    --cc=bo.liu@linux.alibaba.com \
    --cc=djwong@kernel.org \
    --cc=gerry@linux.alibaba.com \
    --cc=hch@infradead.org \
    --cc=hsiangkao@linux.alibaba.com \
    --cc=joseph.qi@linux.alibaba.com \
    --cc=linux-erofs@lists.ozlabs.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH 1/2] iomap: support tail packing inline read' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).