Re: [PATCH] Btrfs: make sure fs_info is not null before its field is used in __btrfs_panic

[Wang Sheng-Hui <shhuiw@gmail.com>]

On 2012年12月08日 18:10, Li Zefan wrote:
> On 2012/12/7 23:42, Wang Sheng-Hui wrote:
>> We should make sure fs_info is not null before we refer to its field.
>> Add simple check here.
> Why? Is there any caller passing NULL @fs_info to this function?

At least for code clean now.

In __btrfs_panic, we have:
276 if (fs_info)
277 s_id = fs_info->sb->s_id;
So for the ->mount_opt field access, we'd better do the check first.

>> Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
>> ---
>>  fs/btrfs/super.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
>> index 915ac14..c6a3633 100644
>> --- a/fs/btrfs/super.c
>> +++ b/fs/btrfs/super.c
>> @@ -280,7 +280,7 @@ void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
>>  	vaf.va = &args;
>>  
>>  	errstr = btrfs_decode_error(fs_info, errno, nbuf);
>> -	if (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR)
>> +	if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
>>  		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
>>  			s_id, function, line, &vaf, errstr);
>>  
>>