Re: [PATCH] devtmpfs: Calling delete_path() only when necessary

[Axel Lin]

2013/12/9 Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>:
> On Mon, Dec 09, 2013 at 04:54:29PM +0800, Axel Lin wrote:
>> 2013/12/9 Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>:
>> > On Wed, Dec 04, 2013 at 02:44:14PM +0800, Axel Lin wrote:
>> >> 2013/12/4 Rob Landley <rob@xxxxxxxxxxx>:
>> >> > On 11/16/2013 02:15:23 AM, Axel Lin wrote:
>> >> >>
>> >> >> The deleted variable is always 1 in current code.
>> >> >> Initialize deleted variable to be 0, so delete_path() will be called only
>> >> >> when
>> >> >> necessary.
>> >> >>
>> >> >> Signed-off-by: Axel Lin <axel.lin@xxxxxxxxxx>
>> >> >
>> >> >
>> >> > I'm not seeing this in linux-next, or a reply on the web archive. Assuming
>> >> > nobody's objected to this, you might want to forward it to
>> >> > trivial@xxxxxxxxxxx
>> >> >
>> >> > That said, you could describe what it _does_ a little more?
>> >>
>> >> I was expecting Greg to pick up this patch.
>> >>
>> >> I thought the description is pretty clear.
>> >> What the patch does is changing the init value of deleted variable to 0.
>> >> The intention of this change is to avoid unnecessary delete_path() call.
>> >
>> > I agree the logic is a bit odd here, but are you seeing an "unnecessary"
>> > delete_path() call happening?  The code has always been like this from
>> > what I can tell...
>>
>> Honestly, I havn't see the "unnecessary" delete_path() call happening druing my
>> test. I look at the code when I was debugging a hangup issue.
>> (In the end, I think the issue is not related to the devtmpfs code.)
>> But I found the logic for the deleted variable looks odd.
>> There are below possible (unlikely) case:
>> When strchr(nodename, '/') != 0 and
>> 1. If dentry->d_inode is NULL
>> 2. vfs_getattr returns error
>> 3. vfs_unlink returns error except -ENOENT.
>>
>> In these cases, delete_path() will fail anyway.
>>
>> Although this is a unlikely case, and I know the code is there since initial
>> commit. But I think it's still good to fix it.
>
> Have you tested your patch to verify nothing breaks?
Yes. I have this patch in my local build image since the day I sent the patch.
Regards,
Axel
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