From: Damien Le Moal <Damien.LeMoal@wdc.com>
To: Jan Kara <jack@suse.cz>, "Darrick J. Wong" <djwong@kernel.org>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
"ceph-devel@vger.kernel.org" <ceph-devel@vger.kernel.org>,
Chao Yu <yuchao0@huawei.com>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Jeff Layton <jlayton@kernel.org>,
Johannes Thumshirn <jth@kernel.org>,
"linux-cifs@vger.kernel.org" <linux-cifs@vger.kernel.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"linux-f2fs-devel@lists.sourceforge.net"
<linux-f2fs-devel@lists.sourceforge.net>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-xfs@vger.kernel.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 04/13] mm: Add functions to lock invalidate_lock for two mappings
Date: Wed, 26 May 2021 12:11:43 +0000 [thread overview]
Message-ID: <DM6PR04MB7081EBE7CE3404AB53F62795E7249@DM6PR04MB7081.namprd04.prod.outlook.com> (raw)
In-Reply-To: 20210526100702.GB30369@quack2.suse.cz
On 2021/05/26 19:07, Jan Kara wrote:
> On Tue 25-05-21 13:48:05, Darrick J. Wong wrote:
>> On Tue, May 25, 2021 at 03:50:41PM +0200, Jan Kara wrote:
>>> Some operations such as reflinking blocks among files will need to lock
>>> invalidate_lock for two mappings. Add helper functions to do that.
>>>
>>> Signed-off-by: Jan Kara <jack@suse.cz>
>>> ---
>>> include/linux/fs.h | 6 ++++++
>>> mm/filemap.c | 38 ++++++++++++++++++++++++++++++++++++++
>>> 2 files changed, 44 insertions(+)
>>>
>>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>>> index 897238d9f1e0..e6f7447505f5 100644
>>> --- a/include/linux/fs.h
>>> +++ b/include/linux/fs.h
>>> @@ -822,6 +822,12 @@ static inline void inode_lock_shared_nested(struct inode *inode, unsigned subcla
>>> void lock_two_nondirectories(struct inode *, struct inode*);
>>> void unlock_two_nondirectories(struct inode *, struct inode*);
>>>
>>> +void filemap_invalidate_down_write_two(struct address_space *mapping1,
>>> + struct address_space *mapping2);
>>> +void filemap_invalidate_up_write_two(struct address_space *mapping1,
>>
>> TBH I find myself wishing that the invalidate_lock used the same
>> lock/unlock style wrappers that we use for i_rwsem.
>>
>> filemap_invalidate_lock(inode1->mapping);
>> filemap_invalidate_lock_two(inode1->i_mapping, inode2->i_mapping);
>
> OK, and filemap_invalidate_lock_shared() for down_read()? I guess that
> works for me.
What about filemap_invalidate_lock_read() and filemap_invalidate_lock_write() ?
That reminds the down_read()/down_write() without the slightly confusing down/up.
>
> Honza
>
>
>> To be fair, I've never been able to keep straight that down means lock
>> and up means unlock. Ah well, at least you didn't use "p" and "v".
>>
>> Mechanically, the changes look ok to me.
>> Acked-by: Darrick J. Wong <djwong@kernel.org>
>>
>> --D
>>
>>> + struct address_space *mapping2);
>>> +
>>> +
>>> /*
>>> * NOTE: in a 32bit arch with a preemptable kernel and
>>> * an UP compile the i_size_read/write must be atomic
>>> diff --git a/mm/filemap.c b/mm/filemap.c
>>> index 4d9ec4c6cc34..d3801a9739aa 100644
>>> --- a/mm/filemap.c
>>> +++ b/mm/filemap.c
>>> @@ -1009,6 +1009,44 @@ struct page *__page_cache_alloc(gfp_t gfp)
>>> EXPORT_SYMBOL(__page_cache_alloc);
>>> #endif
>>>
>>> +/*
>>> + * filemap_invalidate_down_write_two - lock invalidate_lock for two mappings
>>> + *
>>> + * Lock exclusively invalidate_lock of any passed mapping that is not NULL.
>>> + *
>>> + * @mapping1: the first mapping to lock
>>> + * @mapping2: the second mapping to lock
>>> + */
>>> +void filemap_invalidate_down_write_two(struct address_space *mapping1,
>>> + struct address_space *mapping2)
>>> +{
>>> + if (mapping1 > mapping2)
>>> + swap(mapping1, mapping2);
>>> + if (mapping1)
>>> + down_write(&mapping1->invalidate_lock);
>>> + if (mapping2 && mapping1 != mapping2)
>>> + down_write_nested(&mapping2->invalidate_lock, 1);
>>> +}
>>> +EXPORT_SYMBOL(filemap_invalidate_down_write_two);
>>> +
>>> +/*
>>> + * filemap_invalidate_up_write_two - unlock invalidate_lock for two mappings
>>> + *
>>> + * Unlock exclusive invalidate_lock of any passed mapping that is not NULL.
>>> + *
>>> + * @mapping1: the first mapping to unlock
>>> + * @mapping2: the second mapping to unlock
>>> + */
>>> +void filemap_invalidate_up_write_two(struct address_space *mapping1,
>>> + struct address_space *mapping2)
>>> +{
>>> + if (mapping1)
>>> + up_write(&mapping1->invalidate_lock);
>>> + if (mapping2 && mapping1 != mapping2)
>>> + up_write(&mapping2->invalidate_lock);
>>> +}
>>> +EXPORT_SYMBOL(filemap_invalidate_up_write_two);
>>> +
>>> /*
>>> * In order to wait for pages to become available there must be
>>> * waitqueues associated with pages. By using a hash table of
>>> --
>>> 2.26.2
>>>
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2021-05-26 12:11 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 13:50 [PATCH 0/13 v6] fs: Hole punch vs page cache filling races Jan Kara
2021-05-25 13:50 ` [PATCH 01/13] mm: Fix comments mentioning i_mutex Jan Kara
2021-05-25 13:50 ` [PATCH 02/13] documentation: Sync file_operations members with reality Jan Kara
2021-05-25 20:43 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 03/13] mm: Protect operations adding pages to page cache with invalidate_lock Jan Kara
2021-05-25 21:01 ` Darrick J. Wong
2021-05-26 10:00 ` Jan Kara
2021-05-25 13:50 ` [PATCH 04/13] mm: Add functions to lock invalidate_lock for two mappings Jan Kara
2021-05-25 20:48 ` Darrick J. Wong
2021-05-26 10:07 ` Jan Kara
2021-05-26 12:11 ` Damien Le Moal [this message]
2021-05-26 13:45 ` Jan Kara
2021-05-26 15:25 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 05/13] ext4: Convert to use mapping->invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 06/13] ext2: Convert to using invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 07/13] xfs: Convert to use invalidate_lock Jan Kara
2021-05-25 21:37 ` Darrick J. Wong
2021-05-26 10:18 ` Jan Kara
2021-05-26 15:32 ` Darrick J. Wong
2021-05-27 12:01 ` Jan Kara
2021-05-25 21:40 ` Dave Chinner
2021-05-26 10:20 ` Jan Kara
2021-05-26 13:42 ` Jan Kara
2021-05-25 13:50 ` [PATCH 08/13] xfs: Convert double locking of MMAPLOCK to use VFS helpers Jan Kara
2021-05-25 21:41 ` Darrick J. Wong
2021-05-25 13:50 ` [PATCH 09/13] zonefs: Convert to using invalidate_lock Jan Kara
2021-05-25 13:50 ` [PATCH 10/13] f2fs: " Jan Kara
2021-05-26 9:55 ` Chao Yu
2021-05-25 13:50 ` [PATCH 11/13] fuse: " Jan Kara
2021-05-25 13:50 ` [PATCH 12/13] ceph: Fix race between hole punch and page fault Jan Kara
2021-05-25 13:50 ` [PATCH 13/13] cifs: " Jan Kara
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