Re: [PATCH 14/38] fallthru: ext2 fallthru support

From: Miklos Szeredi
Date: Wed Aug 18 2010 - 04:26:56 EST


On Tue, 17 Aug 2010, Valerie Aurora wrote:
> > - hard links to make sure a separate inode is not necessary for each
> > whiteout/fallthrough entry
>
> The problem with hard links is that you run into hard link limits. I
> don't think we can do hard links for whiteouts and fallthrus. Each
> whiteout or fallthru will cost an inode if we implement them as
> extended attributes. This cost has to be balanced against the cost of
> implementing them as dentries, which is mainly code complexity in
> individual file systems.

get_unlinked_inode() is a great idea. But I feel that individual
inodes for each fallthrough is excessive. It'll make the first
readdir() really really expensive and wastes a lot of disk and memory
for no good reason.

Not sure how to fix the hard link limits problem though...

Thanks,
Miklos
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