Re: [PATCH 3/3] find: take advantage of new gnulib/fts leaf-optimization

[James Youngman]

On Sun, Jan 4, 2009 at 12:09 AM, Eric Blake <address@hidden> wrote:
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> According to James Youngman on 1/3/2009 3:04 PM:
>> 2. There exist other filesystems where (st_links - (0 or 2)) <
>> (subdirectory count).   The only example I can think of offhand is
>> AFS.   There is some incomplete information at
>> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=143111
>
> On cygwin 1.5, remote drives have st_links == 1; and on the upcoming
> cygwin 1.7, all directories have st_links == 1.

This is obviously not a problem case, though.   st_links<2 can be used
as a hint that the leaf optimization cannot work.  Indeed, that's just
how oldfind uses it.

> This is because the cost
> of computing how many subdirectories are within a directory outweighs the
> optimization that can be gained by knowing when all subdirectories have
> been encountered.  At least cygwin 1.7 also adds d_link, so that at least
> optimizations using readdir are possible.
>
> - --
> Don't work too hard, make some time for fun as well!
>
> Eric Blake             address@hidden
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