Re: confused on different inode size

[coly <colyli@gmail.com>]

Theodore:

Thanks for your explaining. I ignored this detail before, it is more
clear to me now.

Best regards.

Coly

在 2007-04-09一的 11:26 -0400，Theodore Tso写道：
> On Mon, Apr 09, 2007 at 10:33:13AM +0800, coly wrote:
> > Theodore:
> > 
> > Thanks for your replying. 
> > 
> > Can I understand this way:
> > * Though sizeof(struct ext4_inode) is 152, the real inode size on disk
> > still depends on mount options.
> 
> Not mount options, but how the filesystem is formatted.  So substitute
> "mount" with "mke2fs", and that would be correct.
> 
> > * If use old inode size, the on disk inode will be 128 bytes.
> > * If use new inode size(e.g. extent option in mount), the on disk inode
> > will be 256, or more bytes.
> 
> s/mount/mke2fs/
> 
> And the on-disk inode size is 256, 512, or some greater power of two,
> up to the filesystem blocksize.
> 
> > * If on disk inode size is 128 bytes, only first 128 bytes of struct
> > ext4_inode take effects.
> 
> Well, there's no space to store the fields beyond the first 128, so
> any features that require the extra inode fields can't be used.
> 
> 						- Ted