linux-kernel - Re: [PATCH v5 5/8] fat: restructure export

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Date:	Thu, 6 Dec 2012 18:43:32 +0900
From:	Namjae Jeon <linkinjeon@...il.com>
To:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Cc:	akpm@...ux-foundation.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Namjae Jeon <namjae.jeon@...sung.com>,
	Ravishankar N <ravi.n1@...sung.com>,
	Amit Sahrawat <a.sahrawat@...sung.com>
Subject: Re: [PATCH v5 5/8] fat: restructure export_operations

2012/12/6, OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>:
> Namjae Jeon <linkinjeon@...il.com> writes:
>
>>> I know encode_fh(). But NFS is network protocol, and network can input
>>> any data, and I guess the userland interface (open_by_handle()?) can be
>>> any too.
>>>
>>> And generic_fh_to_dentry()'s input verify choose to check the minimum
>>> length only. But your logic choose the exact length.
>>>
>>> I think the both is sane and correct. But I wonder why did you changed
>>> it.
>> There was no particular reason for us to put those conditions. It is
>> just we knew what fh lengths we have chosen for the 2 cases
>> WITH/WITHOUT parent.
>> i.e., we checked with encoded length.
>> Now, when I check the export functions of other filesystems(btrfs,
>> nilfs2, udf). They also adopt the same method of checking the exact
>> length and type.
>> If there is any particular reason, we will look into that and can also
>> updated on that.
>
> OK. Then, just cleanup code, and let's use strict checking version.
>
> Removing strange fallthrou, something like the following.
>
> static struct dentry *fat_fh_to_dentry_nostale(struct super_block *sb,
> 					       struct fid *fh, int fh_len,
> 					       int fh_type)
> {
> 	struct inode *inode = NULL;
> 	struct fat_fid *fid = (struct fat_fid *)fh;
> 	loff_t i_pos;
>
> 	switch (fh_type) {
> 	case FILEID_FAT_WITHOUT_PARENT:
> 		if (fh_len < FAT_FID_SIZE_WITHOUT_PARENT)
> 			return NULL;
> 		break;
> 	case FILEID_FAT_WITH_PARENT:
> 		if (fh_len < FAT_FID_SIZE_WITH_PARENT)
> 			return NULL;
> 		break;
> 	default:
> 		return NULL;
> 	}
>
> 	i_pos = fid->i_pos_hi;
> 	i_pos = (i_pos << 32) | (fid->i_pos_low);
> 	inode = __fat_nfs_get_inode(sb, 0, fid->i_gen, i_pos);
>
> 	return d_obtain_alias(inode);
> }
Okay. I will change like this on next patch-set.

Thanks OGAWA!
>
>
> --
> OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
>
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