Re: [PATCH] quota: fix to propagate error of mark_dquot_dirty() to caller

[Chao Yu <chao@xxxxxxxxxx>]

On 2024/4/12 21:01, Jan Kara wrote:
> 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@xxxxxxxxxx>
> >
> > 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

Correct, I missed that case.

> and eventually we've crashed in ext4_create().  I've fixed up the patch to
> make mark_all_dquots() return 0 or error.

Thank you for catching and fixing it.

Thanks,

> 								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@xxxxxxxx>
> > SUSE Labs, CR