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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