Received-SPF: pass (google.com: domain of linux-kernel+bounces-174226-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Content-Type: text/plain;
	charset=utf-8
Precedence: bulk
Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.500.171.1.1\))
Subject: Re: [PATCH v3 1/1] bcachefs: Move BCACHEFS_STATFS_MAGIC value to UAPI
 magic.h
From: Glass Su <glass.su@suse.com>
In-Reply-To: <20240509061718.GA231218@pevik>
Date: Thu, 9 May 2024 15:01:33 +0800
Cc: Kent Overstreet <kent.overstreet@linux.dev>,
 linux-bcachefs@vger.kernel.org,
 Su Yue <l@damenly.org>,
 Brian Foster <bfoster@redhat.com>,
 Coly Li <colyli@suse.de>,
 linux-kernel@vger.kernel.org
Content-Transfer-Encoding: quoted-printable
Message-Id: <37665ED1-9929-444F-B9A0-3CC7EADBC064@suse.com>
References: <20240507153757.150891-1-pvorel@suse.cz>
 <6D9FCB08-480D-4CA0-82E2-284B1F2BF8FD@suse.com>
 <20240508211759.GA209026@pevik>
 <fg3cvwvadldeglwrqdeeglswxwupyy2cjki7si7sz3jwsrpzpf@5pkugq7jyzb2>
 <20240509061718.GA231218@pevik>
To: Petr Vorel <pvorel@suse.cz>


> On May 9, 2024, at 14:17, Petr Vorel <pvorel@suse.cz> wrote:
>=20
> Hi Kent,
>=20
>> On Wed, May 08, 2024 at 11:17:59PM +0200, Petr Vorel wrote:
>>> Hi Su, Kent,
>=20
>>>>> On May 7, 2024, at 23:37, Petr Vorel <pvorel@suse.cz> wrote:
>=20
>>>>> Move BCACHEFS_STATFS_MAGIC value to UAPI <linux/magic.h> under
>>>>> BCACHEFS_SUPER_MAGIC definition (use common approach for name) and =
reuse the
>>>>> definition in bcachefs_format.h BCACHEFS_STATFS_MAGIC.
>=20
>>>>> There are other bcachefs magic definitions: BCACHE_MAGIC, =
BCHFS_MAGIC,
>>>>> which use UUID_INIT() and are used only in libbcachefs. Therefore =
move
>>>>> only BCACHEFS_STATFS_MAGIC value, which can be used outside of
>>>>> libbcachefs for f_type field in struct statfs in statfs() or =
fstatfs().
>=20
>>>>> Suggested-by: Su Yue <l@damenly.org>
>=20
>>>> Would you kindly amend it to Su Yue <glass.su@suse.com> or
>>>> Kent can help if the patch is going to be applied.
>=20
>>> Unfortunately Kent was faster, it's already merged without your SUSE =
address
>>> (and your RBT you added in the end):
>=20
>>> =
https://evilpiepirate.org/git/bcachefs.git/commit/?h=3Dfor-next&id=3Dce8f9=
355f23be9756e499682d0d642a741db6c3a
>=20
>>> @Kent: Maybe it can be even now amended (with Su Yue's RBT).
>=20
>> ...sure, make me invalidate my test results :)
>=20
> Thank you! FYI there was also his RBT (Reviewed-by: Su Yue =
<glass.su@suse.com>)
>=20
Thanks both for you Petr and Kent :- )  Sorry for inconvenience due to =
my email quirk...

=E2=80=94=20
Su
> =
https://lore.kernel.org/linux-bcachefs/6D9FCB08-480D-4CA0-82E2-284B1F2BF8F=
D@suse.com/
>=20
> Kind regards,
> Petr
>=20
>>>>> Signed-off-by: Petr Vorel <pvorel@suse.cz>
>>>>> ---
>>>>> Changes v2->v3:
>>>>> * Align tab with other entries.
>>> ...
>>>>> #include <linux/uuid.h>
>>>>> +#include <uapi/linux/magic.h>
>>>>> #include "vstructs.h"
>=20
>>>>> #ifdef __KERNEL__
>>>>> @@ -1275,7 +1276,7 @@ enum bch_compression_opts {
>>>>> UUID_INIT(0xc68573f6, 0x66ce, 0x90a9, \
>>>>> 0xd9, 0x6a, 0x60, 0xcf, 0x80, 0x3d, 0xf7, 0xef)
>=20
>>>>> -#define BCACHEFS_STATFS_MAGIC 0xca451a4e
>>>>> +#define BCACHEFS_STATFS_MAGIC BCACHEFS_SUPER_MAGIC
>=20
>>>>> #define JSET_MAGIC __cpu_to_le64(0x245235c1a3625032ULL)
>>>>> #define BSET_MAGIC __cpu_to_le64(0x90135c78b99e07f5ULL)
>>>>> diff --git a/include/uapi/linux/magic.h =
b/include/uapi/linux/magic.h
>>>>> index 1b40a968ba91..bb575f3ab45e 100644
>>>>> --- a/include/uapi/linux/magic.h
>>>>> +++ b/include/uapi/linux/magic.h
>>>>> @@ -37,6 +37,7 @@
>>>>> #define HOSTFS_SUPER_MAGIC 0x00c0ffee
>>>>> #define OVERLAYFS_SUPER_MAGIC 0x794c7630
>>>>> #define FUSE_SUPER_MAGIC 0x65735546
>>>>> +#define BCACHEFS_SUPER_MAGIC 0xca451a4e
>=20
>>>> IIUC, due to some historical reasons bcachefs used to switched
>>>> ondisk sb magic from BCACHE_MAGIC to BCHFS_MAGIC.
>>>> Other major fses uses  *_SUPER_MAGIC both for ondisk=20
>>>> sb magic, kstatfs::f_type and super_block::s_magic.
>>>> However, for bcacehfs there are three magic numbers.
>=20
>>> Thanks for info. But for struct statfs in statfs() or fstatfs() only =
0xca451a4e
>>> is needed, right? I would not expose the other(s) unless it's really =
needed.
>>> Also we'd need to backport UUID_INIT() into UAPI :(.
>=20
>>>> Anyway, it looks good to me so far:
>>>> Reviewed-by: Su Yue <glass.su@suse.com>=20
>=20
>>> And also without your RBT.
>=20
>>> Kind regards,
>>> Petr
>=20
>>>> =E2=80=94=20
>>>> Su