linux-kernel - Re: [PATCH] ocfs2: check new file size on fallocate call

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Message-ID: <301cdaee-0b73-67b5-75d8-0cbad93b9736@linux.alibaba.com>
Date:   Wed, 31 May 2023 16:31:19 +0800
From:   Joseph Qi <joseph.qi@...ux.alibaba.com>
To:     Luís Henriques <lhenriques@...e.de>
Cc:     Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>,
        Heming Zhao <heming.zhao@...e.com>, ocfs2-devel@....oracle.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ocfs2: check new file size on fallocate call



On 5/31/23 4:29 PM, Luís Henriques wrote:
> Joseph Qi <joseph.qi@...ux.alibaba.com> writes:
> 
>> On 5/29/23 11:26 PM, Luís 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 makes
>>> fstest generic/228 fail.  Simply adding a call to inode_newsize_ok() fixes
>>> this issue.
>>>
>>> Signed-off-by: Luís Henriques <lhenriques@...e.de>
>>> ---
>>>  fs/ocfs2/file.c | 8 +++++++-
>>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> 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, int mode, loff_t offset,
>>>  	struct ocfs2_space_resv sr;
>>>  	int change_size = 1;
>>>  	int cmd = OCFS2_IOC_RESVSP64;
>>> +	int ret = 0;
>>>  
>>>  	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 = 0, which is also valid.  And the
> default '0' will allow size to be changed.
> 

Oops... You are right.

>>>  	if (!ocfs2_writes_unwritten_extents(osb))
>>>  		return -EOPNOTSUPP;
>>>  
>>> -	if (mode & FALLOC_FL_KEEP_SIZE)
>>> +	if (mode & FALLOC_FL_KEEP_SIZE) {
>>>  		change_size = 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,