The cited manual page for getdents is Linux-specific, and does not apply to all filesystem types (for instance, the manual page does not mention
nfs), while GNU find is not platform-specific (its manual page mentions SELinux, which is arguably a useful feature to take into account). It could be optimized for this special case as well.
Even if the feature is available, the manual page recommends:
All applications must properly handle a return of
That is, the information if available can be useful, but it is not guaranteed to be present.
With all of those drawbacks, the developers of
find may not see the need for this optimization. A motivated user could delve into the source code to see how to do this and propose a suitable ifdef'd change.
@Nate Eldredge notes that someone started in this direction. The
find manual states in 7.2 d_type Optimisation
When this feature is enabled, find takes advantage of the fact that on some systems readdir will return the type of a file in struct dirent.
The feature was first mentioned in
2005-01-17 James Youngman <firstname.lastname@example.org>
* configure.in, find/defs.h, find/find.c, find/parser.c, find/pred.c, find/tree.c, find/util.c:
Implemented d_type optimisation but not working correctly, so currently disabled
Later, it was revised to use gnulib to support this:
2010-04-08 James Youngman <email@example.com>
Adopt the use of the gnulib module d-type.
* import-gnulib.config (modules): Import the d-type module.
* configure.ac: Remove old struct dirent.d_type detection logic
(since we now use the gnulib macro from the d-type module for
Version 4.2.2 is rather old (perhaps a typo), by the way: 4.2.3 dates from 2004, and is before these changelog entries. The current release-tag in git is 4.5.14 (mid-2014).
Regardless of the status of a
d_type optimization, the developers are interested in reducing the number of calls to
stat. A note from 4.5.4 (2009-03-10) says for instance:
The ftsfind executable also now avoids calling stat() functions to
discover the inode number of a file, if we already read this
information from the directory. This does provide a speed-up, but
only for a restricted set of commands such as "find . -inum 4001".
This fix is listed below as bug #24342.
In summary: OP asked
Why need to for stat regardless of -L, -H or whatever options.
The reason is that it is a special case which is troublesome to make it work seamlessly instead of
stat for all of the scenarios where
find might need this, and that it takes time to do this.
d_typeis a compile-time option.
find --versionwill tell you if your version was compiled with it.
Features enabled: D_TYPE O_NOFOLLOW(enabled) LEAF_OPTIMISATION FTS() CBO(level=0)