From: Jan Kara <jack@suse.cz>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-xfs@vger.kernel.org, Ted Tso <tytso@mit.edu>,
Amir Goldstein <amir73il@gmail.com>,
Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH 2/7] mm: Protect operations adding pages to page cache with i_mapping_lock
Date: Tue, 13 Apr 2021 15:56:32 +0200 [thread overview]
Message-ID: <20210413135632.GD15752@quack2.suse.cz> (raw)
In-Reply-To: <20210413125746.GB1366579@infradead.org>
On Tue 13-04-21 13:57:46, Christoph Hellwig wrote:
> > if (error == AOP_TRUNCATED_PAGE)
> > put_page(page);
> > + up_read(&mapping->host->i_mapping_sem);
> > return error;
>
> Please add an unlock_mapping label above this up_read and consolidate
> most of the other unlocks by jumping there (put_and_wait_on_page_locked
> probablt can't use it).
Yeah, I've actually simplified the labels even a bit more like:
...
error = filemap_read_page(iocb->ki_filp, mapping, page);
goto unlock_mapping;
unlock:
unlock_page(page);
unlock_mapping:
up_read(&mapping->host->i_mapping_sem);
if (error == AOP_TRUNCATED_PAGE)
put_page(page);
return error;
and everything now jumps to either unlock or unlock_mapping (except for
put_and_wait_on_page_locked() case).
> > truncated:
> > unlock_page(page);
> > @@ -2309,6 +2324,7 @@ static int filemap_update_page(struct kiocb *iocb,
> > return AOP_TRUNCATED_PAGE;
>
> The trunated case actually seems to miss the unlock.
>
> Similarly I think filemap_fault would benefit from a common
> unlock path.
Right, thanks for catching that!
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2021-04-13 13:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 11:28 [PATCH 0/7 RFC v3] fs: Hole punch vs page cache filling races Jan Kara
2021-04-13 11:28 ` [PATCH 1/7] mm: Fix comments mentioning i_mutex Jan Kara
2021-04-13 12:38 ` Christoph Hellwig
2021-04-13 11:28 ` [PATCH 2/7] mm: Protect operations adding pages to page cache with i_mapping_lock Jan Kara
2021-04-13 12:57 ` Christoph Hellwig
2021-04-13 13:56 ` Jan Kara [this message]
2021-04-14 0:01 ` Dave Chinner
2021-04-14 12:23 ` Jan Kara
2021-04-14 21:57 ` Dave Chinner
2021-04-15 13:11 ` Jan Kara
2021-04-14 22:25 ` Matthew Wilcox
2021-04-15 2:05 ` Dave Chinner
2021-04-13 11:28 ` [PATCH 3/7] ext4: Convert to use inode->i_mapping_sem Jan Kara
2021-04-13 11:28 ` [PATCH 4/7] ext2: Convert to using i_mapping_sem Jan Kara
2021-04-13 11:28 ` [PATCH 5/7] xfs: Convert to use i_mapping_sem Jan Kara
2021-04-13 13:05 ` Christoph Hellwig
2021-04-13 13:42 ` Jan Kara
2021-04-13 11:28 ` [PATCH 6/7] zonefs: Convert to using i_mapping_sem Jan Kara
2021-04-13 11:28 ` [PATCH 7/7] fs: Remove i_mapping_sem protection from .page_mkwrite handlers Jan Kara
2021-04-13 13:09 ` [PATCH 0/7 RFC v3] fs: Hole punch vs page cache filling races Christoph Hellwig
2021-04-13 14:17 ` Jan Kara
2021-04-19 15:20 ` Matthew Wilcox
2021-04-19 16:25 ` Jan Kara
2021-04-20 22:12 ` Dave Chinner
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