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

[liuxue <liuxueliu.liu@huawei.com>]

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:

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,
>>   	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;
>> +
>>   	/* 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 */
>> +
>>   #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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