Re: [PATCH 0/4] Fiemap, an extent mapping ioctl - round 2

[Jamie Lokier <jamie@shareable.org>]

> > Because xattrs tend to contain user data, not metadata?
> 
> Agreed, I don't see anything particularly strange about returning the
> xattr mapping, and to me it's not particularly fs specific  (well, the
> detailed format of the on-disk data might be, i.e. the layout of names &
> values within that blob of data, but it is still user data... I guess
> it's something of a grey area).

I'm thinking that some filesystems won't store it as a 'blob' at all,
but as, for example, leaves in a whole-fs tree structure on the same
footing as permissions, size, etc.

I don't see a problem with the xattr feature - it might be useful on
several filesystems.  (For my own program which tries to call stat()
in disk layout order to reduce seeks, knowing xattr blocks _would_ be
useful, as it could try to get xattrs in disk layout order too).

I just wanted to bring up that "all the xattrs of one inode" aren't
necessarily a blob of data in the same way as ordinary contents.
(Just in case it's being assumed that it is.)

-- Jamie