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Date:   Thu, 24 Jan 2019 16:52:15 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: sync filesystem after roll-forward
 recovery
Message-ID: <20190125005215.GA2196@jaegeuk-macbookpro.roam.corp.google.com>
References: <20190123000229.45236-1-jaegeuk@kernel.org>
 <20190123000229.45236-2-jaegeuk@kernel.org>
 <fc1eab1c-f752-c44a-6ebf-338b1fdad741@huawei.com>
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On 01/24, Chao Yu wrote:
> On 2019/1/23 8:02, Jaegeuk Kim wrote:
> > Some works after roll-forward recovery can get an error which will release
> > all the data structures. Let's flush them in order to make it clean.
> > 
> > One possible corruption came from:
> > 
> > [   90.400500] list_del corruption. prev->next should be ffffffed1f566208, but was (null)
> > [   90.675349] Call trace:
> > [   90.677869]  __list_del_entry_valid+0x94/0xb4
> > [   90.682351]  remove_dirty_inode+0xac/0x114
> > [   90.686563]  __f2fs_write_data_pages+0x6a8/0x6c8
> > [   90.691302]  f2fs_write_data_pages+0x40/0x4c
> > [   90.695695]  do_writepages+0x80/0xf0
> > [   90.699372]  __writeback_single_inode+0xdc/0x4ac
> > [   90.704113]  writeback_sb_inodes+0x280/0x440
> > [   90.708501]  wb_writeback+0x1b8/0x3d0
> > [   90.712267]  wb_workfn+0x1a8/0x4d4
> > [   90.715765]  process_one_work+0x1c0/0x3d4
> > [   90.719883]  worker_thread+0x224/0x344
> > [   90.723739]  kthread+0x120/0x130
> > [   90.727055]  ret_from_fork+0x10/0x18
> > 
> > Reported-by: Sahitya Tummala <stummala@codeaurora.org>
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/checkpoint.c |  5 +++--
> >  fs/f2fs/node.c       |  4 +++-
> >  fs/f2fs/super.c      | 42 +++++++++++++++++++++++++++++++-----------
> >  3 files changed, 37 insertions(+), 14 deletions(-)
> > 
> > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > index f955cd3e0677..ccccf0ce2f06 100644
> > --- a/fs/f2fs/checkpoint.c
> > +++ b/fs/f2fs/checkpoint.c
> > @@ -306,8 +306,9 @@ static int f2fs_write_meta_pages(struct address_space *mapping,
> >  		goto skip_write;
> >  
> >  	/* collect a number of dirty meta pages and write together */
> > -	if (wbc->for_kupdate ||
> > -		get_pages(sbi, F2FS_DIRTY_META) < nr_pages_to_skip(sbi, META))
> > +	if (wbc->sync_mode != WB_SYNC_ALL &&
> > +			get_pages(sbi, F2FS_DIRTY_META) <
> > +					nr_pages_to_skip(sbi, META))
> >  		goto skip_write;
> >  
> >  	/* if locked failed, cp will flush dirty pages instead */
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index 4f450e573312..f6ff84e29749 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -1920,7 +1920,9 @@ static int f2fs_write_node_pages(struct address_space *mapping,
> >  	f2fs_balance_fs_bg(sbi);
> >  
> >  	/* collect a number of dirty node pages and write together */
> > -	if (get_pages(sbi, F2FS_DIRTY_NODES) < nr_pages_to_skip(sbi, NODE))
> > +	if (wbc->sync_mode != WB_SYNC_ALL &&
> > +			get_pages(sbi, F2FS_DIRTY_NODES) <
> > +					nr_pages_to_skip(sbi, NODE))
> >  		goto skip_write;
> >  
> >  	if (wbc->sync_mode == WB_SYNC_ALL)
> > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > index 7998ff5418f2..2af0db2b738e 100644
> > --- a/fs/f2fs/super.c
> > +++ b/fs/f2fs/super.c
> > @@ -1456,9 +1456,16 @@ static int f2fs_enable_quotas(struct super_block *sb);
> >  
> >  static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
> >  {
> > +	unsigned int s_flags = sbi->sb->s_flags;
> >  	struct cp_control cpc;
> > -	int err;
> > +	int err = 0;
> > +	int ret;
> >  
> > +	if (s_flags & SB_RDONLY) {
> > +		f2fs_msg(sbi->sb, KERN_ERR,
> > +				"checkpoint=disable on readonly fs");
> > +		return -EINVAL;
> > +	}
> >  	sbi->sb->s_flags |= SB_ACTIVE;
> >  
> >  	f2fs_update_time(sbi, DISABLE_TIME);
> > @@ -1466,18 +1473,24 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
> >  	while (!f2fs_time_over(sbi, DISABLE_TIME)) {
> >  		mutex_lock(&sbi->gc_mutex);
> >  		err = f2fs_gc(sbi, true, false, NULL_SEGNO);
> > -		if (err == -ENODATA)
> > +		if (err == -ENODATA) {
> > +			err = 0;
> >  			break;
> > +		}
> >  		if (err && err != -EAGAIN)
> > -			return err;
> > +			break;
> 
> Should be?
> 
> if (err) {
> 	if (err == -EAGAIN)
> 		err = 0;

Have to report EAGAIN, but not for ENODATA.

> 	else
> 		break;
> }
> 
> Thanks,
> 
> >  	}
> >  
> > -	err = sync_filesystem(sbi->sb);
> > -	if (err)
> > -		return err;
> > +	ret = sync_filesystem(sbi->sb);
> > +	if (ret || err) {
> > +		err = ret ? ret: err;
> > +		goto restore_flag;
> > +	}
> >  
> > -	if (f2fs_disable_cp_again(sbi))
> > -		return -EAGAIN;
> > +	if (f2fs_disable_cp_again(sbi)) {
> > +		err = -EAGAIN;
> > +		goto restore_flag;
> > +	}
> >  
> >  	mutex_lock(&sbi->gc_mutex);
> >  	cpc.reason = CP_PAUSE;
> > @@ -1486,7 +1499,9 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
> >  
> >  	sbi->unusable_block_count = 0;
> >  	mutex_unlock(&sbi->gc_mutex);
> > -	return 0;
> > +restore_flag:
> > +	sbi->sb->s_flags = s_flags;	/* Restore MS_RDONLY status */
> > +	return err;
> >  }
> >  
> >  static void f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
> > @@ -3356,7 +3371,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >  	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
> >  		err = f2fs_disable_checkpoint(sbi);
> >  		if (err)
> > -			goto free_meta;
> > +			goto sync_free_meta;
> >  	} else if (is_set_ckpt_flags(sbi, CP_DISABLED_FLAG)) {
> >  		f2fs_enable_checkpoint(sbi);
> >  	}
> > @@ -3369,7 +3384,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >  		/* After POR, we can run background GC thread.*/
> >  		err = f2fs_start_gc_thread(sbi);
> >  		if (err)
> > -			goto free_meta;
> > +			goto sync_free_meta;
> >  	}
> >  	kvfree(options);
> >  
> > @@ -3391,6 +3406,11 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
> >  	f2fs_update_time(sbi, REQ_TIME);
> >  	return 0;
> >  
> > +sync_free_meta:
> > +	/* safe to flush all the data */
> > +	sync_filesystem(sbi->sb);
> > +	retry = false;
> > +
> >  free_meta:
> >  #ifdef CONFIG_QUOTA
> >  	f2fs_truncate_quota_inode_pages(sb);
> >