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Date: Fri, 12 Apr 2024 15:01:30 +0200
From: Jan Kara <jack@suse.cz>
To: Chao Yu <chao@kernel.org>
Cc: Jan Kara <jack@suse.com>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] quota: fix to propagate error of mark_dquot_dirty() to
 caller
Message-ID: <20240412130130.m4msohzpiojtve7r@quack3>
References: <20240412094942.2131243-1-chao@kernel.org>
 <20240412121517.dydwqiqkdzvwpwf5@quack3>
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In-Reply-To: <20240412121517.dydwqiqkdzvwpwf5@quack3>

On Fri 12-04-24 14:15:17, Jan Kara wrote:
> On Fri 12-04-24 17:49:42, Chao Yu wrote:
> > in order to let caller be aware of failure of mark_dquot_dirty().
> > 
> > Signed-off-by: Chao Yu <chao@kernel.org>
> 
> Thanks. I've added the patch to my tree.

So this patch was buggy because mark_all_dquots() dirty was returning 1 in
case some dquot was indeed dirtied which resulted in e.g.
dquot_alloc_inode() to return 1 and consequently __ext4_new_inode() to fail
and eventually we've crashed in ext4_create().  I've fixed up the patch to
make mark_all_dquots() return 0 or error.

								Honza

> > ---
> >  fs/quota/dquot.c | 21 ++++++++++++++-------
> >  1 file changed, 14 insertions(+), 7 deletions(-)
> > 
> > diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> > index dacbee455c03..b2a109d8b198 100644
> > --- a/fs/quota/dquot.c
> > +++ b/fs/quota/dquot.c
> > @@ -1737,7 +1737,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
> >  
> >  	if (reserve)
> >  		goto out_flush_warn;
> > -	mark_all_dquot_dirty(dquots);
> > +	ret = mark_all_dquot_dirty(dquots);
> >  out_flush_warn:
> >  	srcu_read_unlock(&dquot_srcu, index);
> >  	flush_warnings(warn);
> > @@ -1786,7 +1786,7 @@ int dquot_alloc_inode(struct inode *inode)
> >  warn_put_all:
> >  	spin_unlock(&inode->i_lock);
> >  	if (ret == 0)
> > -		mark_all_dquot_dirty(dquots);
> > +		ret = mark_all_dquot_dirty(dquots);
> >  	srcu_read_unlock(&dquot_srcu, index);
> >  	flush_warnings(warn);
> >  	return ret;
> > @@ -1990,7 +1990,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
> >  	qsize_t inode_usage = 1;
> >  	struct dquot __rcu **dquots;
> >  	struct dquot *transfer_from[MAXQUOTAS] = {};
> > -	int cnt, index, ret = 0;
> > +	int cnt, index, ret = 0, err;
> >  	char is_valid[MAXQUOTAS] = {};
> >  	struct dquot_warn warn_to[MAXQUOTAS];
> >  	struct dquot_warn warn_from_inodes[MAXQUOTAS];
> > @@ -2087,8 +2087,12 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
> >  	 * mark_all_dquot_dirty().
> >  	 */
> >  	index = srcu_read_lock(&dquot_srcu);
> > -	mark_all_dquot_dirty((struct dquot __rcu **)transfer_from);
> > -	mark_all_dquot_dirty((struct dquot __rcu **)transfer_to);
> > +	err = mark_all_dquot_dirty((struct dquot __rcu **)transfer_from);
> > +	if (err < 0)
> > +		ret = err;
> > +	err = mark_all_dquot_dirty((struct dquot __rcu **)transfer_to);
> > +	if (err < 0)
> > +		ret = err;
> >  	srcu_read_unlock(&dquot_srcu, index);
> >  
> >  	flush_warnings(warn_to);
> > @@ -2098,7 +2102,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
> >  	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
> >  		if (is_valid[cnt])
> >  			transfer_to[cnt] = transfer_from[cnt];
> > -	return 0;
> > +	return ret;
> >  over_quota:
> >  	/* Back out changes we already did */
> >  	for (cnt--; cnt >= 0; cnt--) {
> > @@ -2726,6 +2730,7 @@ static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
> >  	struct mem_dqblk *dm = &dquot->dq_dqb;
> >  	int check_blim = 0, check_ilim = 0;
> >  	struct mem_dqinfo *dqi = &sb_dqopt(dquot->dq_sb)->info[dquot->dq_id.type];
> > +	int ret;
> >  
> >  	if (di->d_fieldmask & ~VFS_QC_MASK)
> >  		return -EINVAL;
> > @@ -2807,7 +2812,9 @@ static int do_set_dqblk(struct dquot *dquot, struct qc_dqblk *di)
> >  	else
> >  		set_bit(DQ_FAKE_B, &dquot->dq_flags);
> >  	spin_unlock(&dquot->dq_dqb_lock);
> > -	mark_dquot_dirty(dquot);
> > +	ret = mark_dquot_dirty(dquot);
> > +	if (ret < 0)
> > +		return ret;
> >  
> >  	return 0;
> >  }
> > -- 
> > 2.40.1
> > 
> -- 
> Jan Kara <jack@suse.com>
> SUSE Labs, CR
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR