linux-kernel - Re: [PATCH] f2fs: avoid attaching SB

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Date:   Wed, 23 Jun 2021 08:49:37 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <chao@...nel.org>
Cc:     Chao Yu <yuchao0@...wei.com>,
        linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Zhang Yi <yi.zhang@...wei.com>,
        Jan Kara <jack@...e.cz>
Subject: Re: [PATCH] f2fs: avoid attaching SB_ACTIVE flag during mount/remount

On 06/23, Chao Yu wrote:
> Hi Jaegeuk,
> 
> On 2021/6/23 16:09, Jaegeuk Kim wrote:
> > Hi Chao,
> > 
> > I'll remove this patch, since it breaks checkpoint=disable and recovery
> > flow that check SB_ACTIVE.
> 
> Oh, sorry, is it due to changes in f2fs_disable_checkpoint()?
> 
> So how about testing with changes f2fs_recover_orphan_inodes() and
> f2fs_recover_fsync_data()?

I'm now nervous whether the test can miss corner cases. So, I don't think
we need to pour our time for this nice-to-have patch.

> 
> Thanks,
> 
> > 
> > Thanks,
> > 
> > On 05/25, Chao Yu wrote:
> > > Quoted from [1]
> > > 
> > > "I do remember that I've added this code back then because otherwise
> > > orphan cleanup was losing updates to quota files. But you're right
> > > that now I don't see how that could be happening and it would be nice
> > > if we could get rid of this hack"
> > > 
> > > [1] https://lore.kernel.org/linux-ext4/99cce8ca-e4a0-7301-840f-2ace67c551f3@huawei.com/T/#m04990cfbc4f44592421736b504afcc346b2a7c00
> > > 
> > > Related fix in ext4 by
> > > commit 72ffb49a7b62 ("ext4: do not set SB_ACTIVE in ext4_orphan_cleanup()").
> > > 
> > > f2fs has the same hack implementation in
> > > - f2fs_recover_orphan_inodes()
> > > - f2fs_recover_fsync_data()
> > > - f2fs_disable_checkpoint()
> > > 
> > > Let's get rid of this hack as well in f2fs.
> > > 
> > > Cc: Zhang Yi <yi.zhang@...wei.com>
> > > Cc: Jan Kara <jack@...e.cz>
> > > Signed-off-by: Chao Yu <yuchao0@...wei.com>
> > > ---
> > >   fs/f2fs/checkpoint.c |  3 ---
> > >   fs/f2fs/recovery.c   |  8 ++------
> > >   fs/f2fs/super.c      | 11 ++++-------
> > >   3 files changed, 6 insertions(+), 16 deletions(-)
> > > 
> > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
> > > index 6c208108d69c..a578c7d13d81 100644
> > > --- a/fs/f2fs/checkpoint.c
> > > +++ b/fs/f2fs/checkpoint.c
> > > @@ -691,9 +691,6 @@ int f2fs_recover_orphan_inodes(struct f2fs_sb_info *sbi)
> > >   	}
> > >   #ifdef CONFIG_QUOTA
> > > -	/* Needed for iput() to work correctly and not trash data */
> > > -	sbi->sb->s_flags |= SB_ACTIVE;
> > > -
> > >   	/*
> > >   	 * Turn on quotas which were not enabled for read-only mounts if
> > >   	 * filesystem has quota feature, so that they are updated correctly.
> > > diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
> > > index 4b2f7d1d5bf4..4cfe36fa41be 100644
> > > --- a/fs/f2fs/recovery.c
> > > +++ b/fs/f2fs/recovery.c
> > > @@ -782,8 +782,6 @@ int f2fs_recover_fsync_data(struct f2fs_sb_info *sbi, bool check_only)
> > >   	}
> > >   #ifdef CONFIG_QUOTA
> > > -	/* Needed for iput() to work correctly and not trash data */
> > > -	sbi->sb->s_flags |= SB_ACTIVE;
> > >   	/* Turn on quotas so that they are updated correctly */
> > >   	quota_enabled = f2fs_enable_quota_files(sbi, s_flags & SB_RDONLY);
> > >   #endif
> > > @@ -811,10 +809,8 @@ int f2fs_recover_fsync_data(struct f2fs_sb_info *sbi, bool check_only)
> > >   	err = recover_data(sbi, &inode_list, &tmp_inode_list, &dir_list);
> > >   	if (!err)
> > >   		f2fs_bug_on(sbi, !list_empty(&inode_list));
> > > -	else {
> > > -		/* restore s_flags to let iput() trash data */
> > > -		sbi->sb->s_flags = s_flags;
> > > -	}
> > > +	else
> > > +		f2fs_bug_on(sbi, sbi->sb->s_flags & SB_ACTIVE);
> > >   skip:
> > >   	fix_curseg_write_pointer = !check_only || list_empty(&inode_list);
> > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> > > index 0a77808ebb8f..e7bd983fbddc 100644
> > > --- a/fs/f2fs/super.c
> > > +++ b/fs/f2fs/super.c
> > > @@ -1881,17 +1881,15 @@ 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 = 0;
> > >   	int ret;
> > >   	block_t unusable;
> > > -	if (s_flags & SB_RDONLY) {
> > > +	if (sbi->sb->s_flags & SB_RDONLY) {
> > >   		f2fs_err(sbi, "checkpoint=disable on readonly fs");
> > >   		return -EINVAL;
> > >   	}
> > > -	sbi->sb->s_flags |= SB_ACTIVE;
> > >   	f2fs_update_time(sbi, DISABLE_TIME);
> > > @@ -1909,13 +1907,13 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
> > >   	ret = sync_filesystem(sbi->sb);
> > >   	if (ret || err) {
> > >   		err = ret ? ret : err;
> > > -		goto restore_flag;
> > > +		goto out;
> > >   	}
> > >   	unusable = f2fs_get_unusable_blocks(sbi);
> > >   	if (f2fs_disable_cp_again(sbi, unusable)) {
> > >   		err = -EAGAIN;
> > > -		goto restore_flag;
> > > +		goto out;
> > >   	}
> > >   	down_write(&sbi->gc_lock);
> > > @@ -1931,8 +1929,7 @@ static int f2fs_disable_checkpoint(struct f2fs_sb_info *sbi)
> > >   out_unlock:
> > >   	up_write(&sbi->gc_lock);
> > > -restore_flag:
> > > -	sbi->sb->s_flags = s_flags;	/* Restore SB_RDONLY status */
> > > +out:
> > >   	return err;
> > >   }
> > > -- 
> > > 2.29.2