Re: [PATCH v3 2/5] fat: allocate persistent inode numbers

From: Namjae Jeon <linkinjeon@gmail.com>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: akpm@linux-foundation.org, bfields@fieldses.org,
	viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org,
	Namjae Jeon <namjae.jeon@samsung.com>,
	Ravishankar N <ravi.n1@samsung.com>,
	Amit Sahrawat <a.sahrawat@samsung.com>
Subject: Re: [PATCH v3 2/5] fat: allocate persistent inode numbers
Date: Mon, 24 Sep 2012 23:35:11 +0900	[thread overview]
Message-ID: <CAKYAXd9Men4x5vut=j9Cg8sdtOp+J1kVvd7xqEiOz3jihP_XfA@mail.gmail.com> (raw)
In-Reply-To: <87txun4n5r.fsf@devron.myhome.or.jp>

2012/9/24, OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
> Namjae Jeon <linkinjeon@gmail.com> writes:
>
>> 2012/9/24, OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>:
>>> Namjae Jeon <linkinjeon@gmail.com> writes:
>>>
>>>>> I see. fileid seems to be stat.ino on nfsd4. inode->i_ino is actually
>>>>> just a hash key of inode hash (exception is only in audit, iirc).
>>>>>
>>>>> So, what happens if we set "stat->ino = i_pos" on fat_getattr().
>>>>>
>>>>> int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct
>>>>> kstat
>>>>> *stat)
>>>>> {
>>>>> 	struct inode *inode = dentry->d_inode;
>>>>> 	generic_fillattr(inode, stat);
>>>>> 	stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
>>>>> 	if (opts->nfs == FAT_NFS_LIMITED) {
>>>>> 		/* Use i_pos for ino. This is used as fileid of nfs. */
>>>>> 		stat->ino = MSDOS_SB(inode->i_sb)->i_pos;
>>>
>>> 		stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb), inode);
>>>
>>> Ouch, I forgot to use fat_i_pos_read().
>>>
>> There is some unclear thing.
>> When I see first mail, I think maybe you don't want to use i_pos for
>> inode->ino.
>> FAT allocate inode->ino from i_unique on server side and If NFS client
>> use i_pos for inode->ino in fat_get_attr, inode numbers on each
>> client/server will still be mismatched.
>>
>> Would you plz give me hint ?
>
> ->i_ino is long. It can't hold i_pos fully on 32bit arch, so we can't
> use ->i_no to store i_pos, and changing ->i_ino is unnecessary. If
> getattr() returned i_pos as ino, nobody see ->i_ino anymore except
> internal of kernel.
>
> Furthermore I think there is no issue even if server and client didn't
> have same ino. Because client just uses FH (nfs4 seems to be using
> stat.ino though).
Okay, I will share the result after checking and testing more(nfsv3 and nfsv4).
Thanks a lot!
> --
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
>