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

[Chao Yu <chao@kernel.org>]

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@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

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@suse.com>
>> SUSE Labs, CR
>>