Dave Kleikamp wrote:
> On Tue, 2007-06-05 at 06:41 -0500, Jose R. Santos wrote:
>> On Mon, 04 Jun 2007 16:01:45 -0700
>> Mingming Cao <cmm@xxxxxxxxxx> wrote:
>>
>>> On Mon, 2007-06-04 at 11:57 -0600, Andreas Dilger wrote:
>>>> On Jun 04, 2007 11:32 -0500, Jose R. Santos wrote:
>>>>> Set the journals JBD2_FEATURE_INCOMPAT_64BIT on devices with more
>>>>> than 32bit block sizes during mount time. This ensure proper record
>>>>> lenth when writing to the journal.
>>>>>
>>>>> Signed-off-by: Jose R. Santos <jrs@xxxxxxxxxx>
>>>>> ---
>>>>> fs/ext4/super.c | 11 +++++++++++
>>>>> 1 file changed, 11 insertions(+)
>>>>>
>>>>> Index: linux-2.6.22-rc3/fs/ext4/super.c
>>>>> ===================================================================
>>>>> --- linux-2.6.22-rc3.orig/fs/ext4/super.c 2007-06-04 11:01:20.028360650 -0500
>>>>> +++ linux-2.6.22-rc3/fs/ext4/super.c 2007-06-04 11:05:11.389126418 -0500
>>>>> @@ -1824,6 +1824,17 @@ static int ext4_fill_super (struct super
>>>>> goto failed_mount3;
>>>>> }
>>>>>
>>>>> + /*
>>>>> + * Make sure to set JBD2_FEATURE_INCOMPAT_64BIT on filesystems
>>>>> + * with more that 32-bit block counts
>>>>> + */
>>>>> + if(es->s_blocks_count_hi &&
>>> This need to be le32_to_cpu(es->s_blocks_count_hi)
>> I'm curious,
>>
>> Why do we need to do an endian conversion to check for a non-zero value
>> in s_blocks_count_hi? Seems unnecessary here.
>
> Jose is right. The endian conversion is unnecessary.
>
> Shaggy
But by using le32_to_cpu(es->s_blocks_count_hi) you explicitly mark the variable
as a little-endian.
So if someone reads the code, he knows this is a little-endian value and this
allows to avoid errors if later variable must be tested for other value than 0.
For instance, you have :
if(es->s_blocks_count_hi)
and later the value should be compared to 10, how do you know easily you should use:
if (le32_to_cpu(es->s_blocks_count_hi) == 10)
instead of
if(es->s_blocks_count_hi == 10)
I think writing like Mingming asks should allow to avoid errors later.
(and code becomes really self-explicit...)
Regards,
Laurent
--
------------- Laurent.Vivier@xxxxxxxx --------------
"Any sufficiently advanced technology is
indistinguishable from magic." - Arthur C. Clarke
Attachment:
signature.asc
Description: OpenPGP digital signature
