Re: [PATCH] f2fs: add a max block count for f2fs_map_blocks

[He YunLei <heyunlei@huawei.com>]

On 2015/12/26 21:21, Chao Yu wrote:
> Hi,
>
> On 12/25/15 6:17 PM, liuxue wrote:
>> On 2015/12/25 17:25, Chao Yu wrote:
>>> Hi,
>>>
>>>> -----Original Message-----
>>>> From: Yunlei He [mailto:heyunlei@huawei.com]
>>>> Sent: Friday, December 25, 2015 4:48 PM
>>>> To: linux-f2fs-devel@lists.sourceforge.net; jaegeuk@kernel.org; chao2.yu@samsung.com
>>>> Cc: bintian.wang@huawei.com; Yunlei He; Xue Liu
>>>> Subject: [PATCH] f2fs: add a max block count for f2fs_map_blocks
>>>>
>>>> This patch adds a max block count for f2fs_map_blocks
>>>
>>> Maximum file size should be limited by sb->s_maxbytes which was inited
>>> in max_file_size(), so logical block index should not exceed the value
>>> calculated with maxbytes, why would we limit logical block index with
>>> another value?
>>>
>>> Thanks,
>>>
>>
>> Hi,
>> Trinity test program will send a block number as parameter into ioctl_fibmap, which will be used in
>> get_node_path(), when the block number large than f2fs max blocks, it will trigger kernel bug.
>> So we judge the block number in f2fs_map_blocks(), which reference ext4:
>
> Thanks for the explanation, and this makes sense to me, it's better to add above
> message in commit log.
>
>>
>> file: fs/ext4/inode.c
>> function: ext4_map_blocks()
>>
>>       /* We can handle the block number less than EXT_MAX_BLOCKS */
>>       if (unlikely(map->m_lblk >= EXT_MAX_BLOCKS))
>>           return -EFSCORRUPTED;
>>
>>
>>>>
>>>> Signed-off-by: Yunlei He <heyunlei@huawei.com>
>>>> Signed-off-by: Xue Liu <liuxueliu.liu@huawei.com>
>>>> ---
>>>>    fs/f2fs/data.c | 4 ++++
>>>>    fs/f2fs/f2fs.h | 3 +++
>>>>    2 files changed, 7 insertions(+)
>>>>
>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>>> index e34b1bd..2a16c867 100644
>>>> --- a/fs/f2fs/data.c
>>>> +++ b/fs/f2fs/data.c
>>>> @@ -578,6 +578,10 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>
> As you mentioned, this bug will only be triggered in bmap, so how about checking
> upper boundary in get_data_block_bmap? Since we could remain bug_on in
> get_node_path for other call paths to check whether this is a bug of VFS or not.
>
yeah, change here maybe influence dio and fiemap.
>>>>    	map->m_len = 0;
>>>>    	map->m_flags = 0;
>>>>
>>>> +	/* We can handle the block number less than F2FS_MAX_BLOCKS */
>>>> +	if (unlikely(map->m_lblk >= F2FS_MAX_BLOCKS))
>>>> +		return -EUCLEAN;
>
> EFBIG ?

yeah, EFBIG is better.
>
>>>> +
>>>>    	/* it only supports block size == page size */
>>>>    	pgofs =	(pgoff_t)map->m_lblk;
>>>>
>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>>> index 19beabe..911c99b 100644
>>>> --- a/fs/f2fs/f2fs.h
>>>> +++ b/fs/f2fs/f2fs.h
>>>> @@ -331,6 +331,9 @@ enum {
>>>>
>>>>    #define F2FS_LINK_MAX	0xffffffff	/* maximum link count per file */
>>>>
>>>> +
>>>> +#define F2FS_MAX_BLOCKS 0x3F015AFF      /* maximum block count per file */
>
> Can you introduce F2FS_MAX_BLOCKS with calculation detail of constant
> '0x3F015AFF', moreover need to exclude reserved space for inline xattr.
>
> Thanks,

I will send version v2 use max_file_size() function.

Thanks,

>
>>>> +
>>>>    #define MAX_DIR_RA_PAGES	4	/* maximum ra pages of dir */
>>>>
>>>>    /* vector size for gang look-up from extent cache that consists of radix tree */
>>>> --
>>>> 1.9.1
>>>
>>>
>>>
>>> .
>>
>>
>>
>>
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>>
>
> .
>


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