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From: Jeff Layton <jlayton@kernel.org>
To: Jan Kara <jack@suse.cz>,
	linux-fsdevel@vger.kernel.org, Ilya Dryomov <idryomov@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <david@fromorbit.com>,
	ceph-devel@vger.kernel.org, Chao Yu <yuchao0@huawei.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	"Darrick J. Wong" <darrick.wong@oracle.com>,
	Jaegeuk Kim <jaegeuk@kernel.org>,
	Johannes Thumshirn <jth@kernel.org>,
	linux-cifs@vger.kernel.org, linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org,
	linux-xfs@vger.kernel.org, Miklos Szeredi <miklos@szeredi.hu>,
	Steve French <sfrench@samba.org>, Ted Tso <tytso@mit.edu>,
	Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH 10/11] ceph: Fix race between hole punch and page fault
Date: Wed, 12 May 2021 11:19:42 -0400	[thread overview]
Message-ID: <bc8f0ab096e1a7d8ba29655247de7b2c2abfd5f1.camel@kernel.org> (raw)
In-Reply-To: <20210512134631.4053-10-jack@suse.cz>

On Wed, 2021-05-12 at 15:46 +0200, Jan Kara wrote:
> Ceph has a following race between hole punching and page fault:
> 
> CPU1                                  CPU2
> ceph_fallocate()
>   ...
>   ceph_zero_pagecache_range()
>                                       ceph_filemap_fault()
>                                         faults in page in the range being
>                                         punched
>   ceph_zero_objects()
> 
> And now we have a page in punched range with invalid data. Fix the
> problem by using mapping->invalidate_lock similarly to other
> filesystems. Note that using invalidate_lock also fixes a similar race
> wrt ->readpage().
> 
> CC: Jeff Layton <jlayton@kernel.org>
> CC: ceph-devel@vger.kernel.org
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  fs/ceph/addr.c | 9 ++++++---
>  fs/ceph/file.c | 2 ++
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index c1570fada3d8..6d868faf97b5 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -1401,9 +1401,11 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
>  		ret = VM_FAULT_SIGBUS;
>  	} else {
>  		struct address_space *mapping = inode->i_mapping;
> -		struct page *page = find_or_create_page(mapping, 0,
> -						mapping_gfp_constraint(mapping,
> -						~__GFP_FS));
> +		struct page *page;
> +
> +		down_read(&mapping->invalidate_lock);
> +		page = find_or_create_page(mapping, 0,
> +				mapping_gfp_constraint(mapping, ~__GFP_FS));
>  		if (!page) {
>  			ret = VM_FAULT_OOM;
>  			goto out_inline;
> @@ -1424,6 +1426,7 @@ static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
>  		vmf->page = page;
>  		ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
>  out_inline:
> +		up_read(&mapping->invalidate_lock);
>  		dout("filemap_fault %p %llu read inline data ret %x\n",
>  		     inode, off, ret);
>  	}
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 77fc037d5beb..91693d8b458e 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -2083,6 +2083,7 @@ static long ceph_fallocate(struct file *file, int mode,
>  	if (ret < 0)
>  		goto unlock;
>  
> +	down_write(&inode->i_mapping->invalidate_lock);
>  	ceph_zero_pagecache_range(inode, offset, length);
>  	ret = ceph_zero_objects(inode, offset, length);
>  
> @@ -2095,6 +2096,7 @@ static long ceph_fallocate(struct file *file, int mode,
>  		if (dirty)
>  			__mark_inode_dirty(inode, dirty);
>  	}
> +	up_write(&inode->i_mapping->invalidate_lock);
>  
>  	ceph_put_cap_refs(ci, got);
>  unlock:

Assuming the basic concept is sound, then this looks reasonable. 

Reviewed-by: Jeff Layton <jlayton@kernel.org>


  reply	other threads:[~2021-05-12 15:56 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-12 13:46 [PATCH 0/11 v5] fs: Hole punch vs page cache filling races Jan Kara
2021-05-12 13:46 ` [PATCH 01/11] mm: Fix comments mentioning i_mutex Jan Kara
2021-05-12 13:46 ` [PATCH 02/11] documentation: Sync file_operations members with reality Jan Kara
2021-05-12 13:46 ` [PATCH 03/11] mm: Protect operations adding pages to page cache with invalidate_lock Jan Kara
2021-05-12 14:20   ` Matthew Wilcox
2021-05-13 17:49     ` Jan Kara
2021-05-12 14:40   ` Matthew Wilcox
2021-05-13 19:01     ` Jan Kara
2021-05-13 19:38       ` Matthew Wilcox
2021-05-14 11:07         ` Jan Kara
2021-05-12 15:23   ` Darrick J. Wong
2021-05-13 17:44     ` Jan Kara
2021-05-13 18:52       ` Darrick J. Wong
2021-05-13 23:19         ` Dave Chinner
2021-05-14 16:17           ` Darrick J. Wong
2021-05-17 11:21             ` Jan Kara
2021-05-18 22:36             ` Dave Chinner
2021-05-19 10:57               ` Jan Kara
2021-05-12 13:46 ` [PATCH 04/11] ext4: Convert to use mapping->invalidate_lock Jan Kara
2021-05-12 13:46 ` [PATCH 05/11] ext2: Convert to using invalidate_lock Jan Kara
2021-05-12 13:46 ` [PATCH 06/11] xfs: Convert to use invalidate_lock Jan Kara
2021-05-12 13:46 ` [PATCH 07/11] zonefs: Convert to using invalidate_lock Jan Kara
2021-05-13  0:34   ` Damien Le Moal
2021-05-12 13:46 ` [PATCH 08/11] f2fs: " Jan Kara
2021-05-12 13:46 ` [PATCH 09/11] fuse: " Jan Kara
2021-05-12 13:46 ` [PATCH 10/11] ceph: Fix race between hole punch and page fault Jan Kara
2021-05-12 15:19   ` Jeff Layton [this message]
2021-05-12 13:46 ` [PATCH 11/11] cifs: " Jan Kara

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