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

From: Namjae Jeon
Date: Mon Sep 24 2012 - 10:35:06 EST


2012/9/24, OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>:
> Namjae Jeon <linkinjeon@xxxxxxxxx> writes:
>
>> 2012/9/24, OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>:
>>> Namjae Jeon <linkinjeon@xxxxxxxxx> 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@xxxxxxxxxxxxxxxxxx>
>
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