linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@lst.de>,
	linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	"Darrick J . Wong" <djwong@kernel.org>,
	Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
Subject: Re: [PATCH v6] iomap: support tail packing inline read
Date: Fri, 23 Jul 2021 16:56:35 +0100	[thread overview]
Message-ID: <YPrms0fWPwEZGNAL@casper.infradead.org> (raw)
In-Reply-To: <YPre+j906ywgRHEZ@B-P7TQMD6M-0146.local>

On Fri, Jul 23, 2021 at 11:23:38PM +0800, Gao Xiang wrote:
> Hi Matthew,
> 
> On Fri, Jul 23, 2021 at 04:05:29PM +0100, Matthew Wilcox wrote:
> > On Thu, Jul 22, 2021 at 07:39:47AM +0200, Christoph Hellwig wrote:
> > > @@ -675,7 +676,7 @@ static size_t iomap_write_end_inline(struct inode *inode, struct page *page,
> > >  
> > >  	flush_dcache_page(page);
> > >  	addr = kmap_atomic(page);
> > > -	memcpy(iomap->inline_data + pos, addr + pos, copied);
> > > +	memcpy(iomap_inline_buf(iomap, pos), addr + pos, copied);
> > 
> > This is wrong; pos can be > PAGE_SIZE, so this needs to be
> > addr + offset_in_page(pos).
> 
> Yeah, thanks for pointing out. It seems so, since EROFS cannot test
> such write path, previously it was disabled explicitly. I could
> update it in the next version as above.

We're also missing a call to __set_page_dirty_nobuffers().  This
matters to nobody right now -- erofs is read-only and gfs2 only
supports inline data in the inode.  I presume what is happening
for gfs2 is that at inode writeback time, it copies the ~60 bytes
from the page cache into the inode and then schedules the inode
for writeback.

But logically, we should mark the page as dirty.  It'll be marked
as dirty by ->mkwrite, should the page be mmaped, so gfs2 must
already cope with a dirty page for inline data.

  reply	other threads:[~2021-07-23 15:57 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-22  3:17 Gao Xiang
2021-07-22  5:39 ` Christoph Hellwig
2021-07-22  5:56   ` Gao Xiang
2021-07-22 16:51   ` Darrick J. Wong
2021-07-22 16:53     ` Christoph Hellwig
2021-07-22 16:57       ` Matthew Wilcox
2021-07-23  1:26     ` Gao Xiang
2021-07-23  6:22       ` Huang Jianan
2021-07-23 15:05   ` Matthew Wilcox
2021-07-23 15:23     ` Gao Xiang
2021-07-23 15:56       ` Matthew Wilcox [this message]
2021-07-23 16:24         ` 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=YPrms0fWPwEZGNAL@casper.infradead.org \
    --to=willy@infradead.org \
    --cc=andreas.gruenbacher@gmail.com \
    --cc=djwong@kernel.org \
    --cc=hch@lst.de \
    --cc=linux-erofs@lists.ozlabs.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH v6] 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).