Re: [PATCH v6 4/7] fat: restructure export_operations

From: Namjae Jeon
Date: Mon Feb 18 2013 - 09:03:53 EST


2013/2/18 OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>:
> Namjae Jeon <linkinjeon@xxxxxxxxx> writes:
>
>> + if (MSDOS_SB(inode->i_sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
>> + if (inode->i_ino == MSDOS_ROOT_INO)
>> + stat->ino = MSDOS_ROOT_INO;
>
> Can we simply set i_pos = MSDOS_ROOT_INO in fat_read_root()? If so, I
> think we can avoid this check.
Yes, we can. I will change it.

>
>> + else
>> + /* Use i_pos for ino. This is used as fileid of nfs. */
>> + stat->ino = fat_i_pos_read(MSDOS_SB(inode->i_sb),
>> + inode);
>> + }
>> return 0;
>> }
>> EXPORT_SYMBOL_GPL(fat_getattr);
>
>
>> +struct fat_fid {
>> + u32 i_gen;
>> + u32 i_pos_low;
>> + u16 i_pos_hi;
>> + u16 parent_i_pos_hi;
>> + u32 parent_i_pos_low;
>> + u32 parent_i_gen;
>> +} __packed;
>
> Do we need to use __packed? Unnecessary __packed can generate slower
> code for alignment check on arch has unaligned fault.
Actually, I referenced other filesystem's exportfs code like btrfs and xfs.
they are packing their fids.
your opinion is reasonable, so I can fix it as your opinion.
>
>> + if (parent && (len < FAT_FID_SIZE_WITH_PARENT)) {
>> + *lenp = FAT_FID_SIZE_WITH_PARENT;
>> + return 255;
>> + } else if (len < FAT_FID_SIZE_WITHOUT_PARENT) {
>> + *lenp = FAT_FID_SIZE_WITHOUT_PARENT;
>> + return 255;
>> + }
>
> This check strange. "parent && len == FAT_FID_SIZE_WITHOUT_PARENT" will
> overwrite over limit of fh size?
I need to check more. because I followed the logic in
export_encode_fh() function.

Thanks for review!
> --
> OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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