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From:   =?utf-8?Q?Lu=C3=ADs_Henriques?= <lhenriques@suse.de>
To:     Joseph Qi <joseph.qi@linux.alibaba.com>
Cc:     Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>,
        Heming Zhao <heming.zhao@suse.com>, ocfs2-devel@oss.oracle.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ocfs2: check new file size on fallocate call
References: <20230529152645.32680-1-lhenriques@suse.de>
        <810630b9-2021-01b3-1473-aa759174205e@linux.alibaba.com>
Date:   Wed, 31 May 2023 09:29:18 +0100
In-Reply-To: <810630b9-2021-01b3-1473-aa759174205e@linux.alibaba.com> (Joseph
        Qi's message of "Wed, 31 May 2023 14:00:12 +0800")
Message-ID: <87fs7c3nvl.fsf@suse.de>
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Joseph Qi <joseph.qi@linux.alibaba.com> writes:

> On 5/29/23 11:26 PM, Lu=C3=ADs Henriques wrote:
>> When changing a file size with fallocate() the new size isn't being
>> checked.  In particular, the FSIZE ulimit isn't being checked, which mak=
es
>> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fix=
es
>> this issue.
>>=20
>> Signed-off-by: Lu=C3=ADs Henriques <lhenriques@suse.de>
>> ---
>>  fs/ocfs2/file.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>=20
>> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
>> index efb09de4343d..b173c36bcab3 100644
>> --- a/fs/ocfs2/file.c
>> +++ b/fs/ocfs2/file.c
>> @@ -2100,14 +2100,20 @@ static long ocfs2_fallocate(struct file *file, i=
nt mode, loff_t offset,
>>  	struct ocfs2_space_resv sr;
>>  	int change_size =3D 1;
>>  	int cmd =3D OCFS2_IOC_RESVSP64;
>> +	int ret =3D 0;
>>=20=20
>>  	if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
>>  		return -EOPNOTSUPP;
>
> This means we only support keep-size and pouch_hole.
> And it seems pouch_hole will also imply keep-size.

I think you're forgetting about mode =3D 0, which is also valid.  And the
default '0' will allow size to be changed.

>>  	if (!ocfs2_writes_unwritten_extents(osb))
>>  		return -EOPNOTSUPP;
>>=20=20
>> -	if (mode & FALLOC_FL_KEEP_SIZE)
>> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>>  		change_size =3D 0;
>> +	} else {
>
> Seems this will be a dead branch?

Again, you need to consider '0' as a valid mode value.  If you run
generic/228 without this patch you'll see that test failing because it
*does* hit this branch.

Cheers,
--=20
Lu=C3=ADs

>
> Thanks,
> Joseph
>
>> +		ret =3D inode_newsize_ok(inode, offset + len);
>> +		if (ret)
>> +			return ret;
>> +	}
>>=20=20
>>  	if (mode & FALLOC_FL_PUNCH_HOLE)
>>  		cmd =3D OCFS2_IOC_UNRESVSP64;