Re: [Ext2-devel] Re: Shrinking ext3 directories

From: Andreas Dilger (adilger@clusterfs.com)
Date: Wed Jun 19 2002 - 19:24:20 EST


On Jun 20, 2002 00:49 +0200, Daniel Phillips wrote:
> My inclination is to copy the last block of the directory into the
> vacated block as opposed to leaving a hole in the file. The slight
> extra cost doesn't seem to be worth worrying about, and it's guaranteed
> to leave the directory in a compact state when emptied.

This also has the benefit of avoiding huge truncates when we are
deleting lots of files. At most it will add a single block into
each transaction.

> I think it's best to err on the side of simplicity this time: the
> copy-down-last strategy eliminates the need to search for a free
> block when the directory needs to be expanded again,

It also keeps compatibility with older code, whereas having holes in
directories can cause problems on older kernels.

Cheers, Andreas

--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/

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