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Date:   Wed, 29 Jul 2020 09:21:44 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <chao@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com,
        Daeho Jeong <daehojeong@google.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix deadlock between quota writes and
 checkpoint
Message-ID: <20200729162144.GA1460954@google.com>
References: <20200729070244.584518-1-jaegeuk@kernel.org>
 <054f161c-05db-73b7-3d83-be7addcd6015@kernel.org>
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On 07/29, Chao Yu wrote:
> On 2020-7-29 15:02, Jaegeuk Kim wrote:
> > f2fs_write_data_pages(quota_mapping)
> >  __f2fs_write_data_pages             f2fs_write_checkpoint
> >   * blk_start_plug(&plug);
> >   * add bio in write_io[DATA]
> >                                       - block_operations
> >                                       - skip syncing quota by
> >                                                 >DEFAULT_RETRY_QUOTA_FLUSH_COUNT
> >                                       - down_write(&sbi->node_write);
> >   - f2fs_write_single_data_page
> 
> After commit 79963d967b49 ("f2fs: shrink node_write lock coverage"),
> node_write lock was moved to f2fs_write_single_data_page() and
> f2fs_write_compressed_pages().
> 
> So it needs to update the callstack.
> 
> - down_write(node_write)

Yeah, applied. :)

> 
> Otherwise it looks good to me.
> 
> Reviewed-by: Chao Yu <yuchao0@huawei.com>
> 
> Thanks,
> 
> >     - f2fs_do_write_data_page
> >       - f2fs_outplace_write_data
> >         - do_write_page
> >            - f2fs_allocate_data_block
> >             - down_write(node_write)
> >                                       - f2fs_wait_on_all_pages(F2FS_WB_CP_DATA);
> > 
> > Signed-off-by: Daeho Jeong <daehojeong@google.com>
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/checkpoint.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index 8c782d3f324f0..99c8061da55b9 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -1269,6 +1269,8 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
> >  		if (type == F2FS_DIRTY_META)
> >  			f2fs_sync_meta_pages(sbi, META, LONG_MAX,
> >  							FS_CP_META_IO);
> > +		else if (type == F2FS_WB_CP_DATA)
> > +			f2fs_submit_merged_write(sbi, DATA);
> >  		io_schedule_timeout(DEFAULT_IO_TIMEOUT);
> >  	}
> >  	finish_wait(&sbi->cp_wait, &wait);
> >