Re: [PATCH 0/20] return f_fsid for statfs(2)

From: Coly Li
Date: Thu Jan 22 2009 - 14:31:21 EST




Jamie Lokier Wrote:
> Andreas Dilger wrote:
>> On Jan 20, 2009 12:30 +0800, Coly Li wrote:
>>> Ext[234] is sophisticated to have on-disk uuid record. Most file systems
>>> in the patches (except jfs and reiser3) do not have a persistent uuid,
>>> a reasonable/feasible solution without media format modification is fsid
>>> in boot/mount life cycle. That's why huge_encode_dev(sb->s_bdev->bd_dev)
>>> is used here. For jfs and reiserfs3, is there any use case for
>>> persistent fsid cross boots ?
>> I would say yes, this is worthwhile to do, or the fsid can change between
>> boots unnecessarily.
>
> Even FAT has a volume id which should probably be used.
> I'm guessing NTFS does too.
>
vfat volume id is assigned manually in mkfs.vfat, vfat volumes in one machine can be assigned to
same volume id value, even worse the volume id can be modified when volume is mounted. Therefore,
IMHO it's not suitable to be used as a fsid.

--
Coly Li
SuSE Labs
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