Re: (2) [PATCH] f2fs: fix null reference error when checking end of zone

[Chao Yu <chao@kernel.org>]

On 2024/7/4 15:55, Daejun Park wrote:
> Hi Chao Yu,
>>   
>> --------- Original Message ---------
>> Sender : Chao Yu <chao@kernel.org>
>> Date : 2024-07-04 16:16 (GMT+9)
>> Title : Re: [PATCH] f2fs: fix null reference error when checking end of zone
>>   
>> On 2024/7/4 9:01, Daejun Park wrote:
>>> This patch fixes a potentially null pointer being accessed by
>>> is_end_zone_blkaddr() that checks the last block of a zone
>>> when f2fs is mounted as a single device.
>>
>> blkzoned feature depends on multiple device feature? One regular
>> device and one seq-zone device?
> 
> According to mkfs.f2fs, if there are a sufficient number of
> conventional zones, a single zoned device can be used.

Correct.

Anyway, the code looks clean.

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

> 
> Thanks,
> Daejun
> 
>>
>> Thanks,
>>
>>>
>>> Fixes: e067dc3c6b9c ("f2fs: maintain six open zones for zoned devices")
>>> Signed-off-by: Daejun Park <daejun7.park@samsung.com>
>>> ---
>>>    fs/f2fs/data.c 4 +++-
>>>    1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>>> index b6dcb3bcaef7..1aa7eefa659c 100644
>>> --- a/fs/f2fs/data.c
>>> +++ b/fs/f2fs/data.c
>>> @@ -925,6 +925,7 @@ int f2fs_merge_page_bio(struct f2fs_io_info *fio)
>>>    #ifdef CONFIG_BLK_DEV_ZONED
>>>    static bool is_end_zone_blkaddr(struct f2fs_sb_info *sbi, block_t blkaddr)
>>>    {
>>> +        struct block_device *bdev = sbi->sb->s_bdev;
>>>             int devi = 0;
>>>   
>>>             if (f2fs_is_multi_device(sbi)) {
>>> @@ -935,8 +936,9 @@ static bool is_end_zone_blkaddr(struct f2fs_sb_info *sbi, block_t blkaddr)
>>>                             return false;
>>>                     }
>>>                     blkaddr -= FDEV(devi).start_blk;
>>> +                bdev = FDEV(devi).bdev;
>>>             }
>>> -        return bdev_is_zoned(FDEV(devi).bdev) &&
>>> +        return bdev_is_zoned(bdev) &&
>>>                     f2fs_blkz_is_seq(sbi, devi, blkaddr) &&
>>>                     (blkaddr % sbi->blocks_per_blkz == sbi->blocks_per_blkz - 1);
>>>    }