On Fri, Jul 25, 2014 at 01:37:19PM -0400, Abhijith Das wrote:

Hi all,

The topic of a readdirplus-like syscall had come up for discussion at last year's
LSF/MM collab summit. I wrote a couple of syscalls with their GFS2 implementations
to get at a directory's entries as well as stat() info on the individual inodes.
I'm presenting these patches and some early test results on a single-node GFS2
filesystem.

1. dirreadahead() - This patchset is very simple compared to the xgetdents() system
call below and scales very well for large directories in GFS2. dirreadahead() is
designed to be called prior to getdents+stat operations.

Hmm.  Have you tried plumbing these read-ahead calls in under the normal
getdents() syscalls?

We don't have a filereadahead() syscall and yet we somehow manage to
implement buffered file data read-ahead :).

- z