ext2 inode size patch - RE: PR kern/124621

[Peter C. Lai]

On 2008-11-25 10:11:09AM -0500, Josh Carroll wrote:
> > Ok, I describe my concern once more. I do not object against the checking
> > of the inode size. But, if inode size is changed, then some data is added
> > to the inode, that could (and usually does, otherwise why extend it ?)
> > change intrerpetation of the inode. Thus, we need a verification of the
> > fact that simply ignoring added fields does not damage filesystem or
> > cause user data corruption. Verification != testing.
> 
> Ok, I see your point. I will do some more research into the ext2 inode
> structure on disk and see what happens when inode size > 128.

Possibly overstating the obvious, but since e2fsprogs were the ones who
actually initiated the change in default inode size, maybe start digging 
through that to see what it actually does with the other 128 bytes (the
changelog and some posts on comp.os.linux seem to suggest is that it has 
something to do with optimizing extended attributes/acls; basically
extended acls being inaccessible to kernels that ignore the extra data,
and 2.4 kernels refusing to mount those filesystems at all (presumably
due to the same assumption we've been making)).

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Peter C. Lai                 | Bard College at Simon's Rock
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