[Cluster-devel] [GFS2 PATCH 0/2 v2] readdir cookie patches

[Benjamin Marzinski <bmarzins@redhat.com>]

These two patches change the readdir cookies to format that should last a lot
longer before there are collisions. Unlike my last version, they store the
computed cookie in the gfs2_dirent structure, which keeps their performance on
small directories similar to the old code. After that you start reaching the
point where hash indexes reach the maximum depth, and the new code stops
needing to sort them, and performance of the new code quickly surpasses the old
code. For instance, when I contrived a situation where there were 1000 dirents
with the same hash index, the new code "ls -f" time was a less than a tenth of
the old code, 0.003s vs 0.036s. However, this is a pretty unrealistic size,
since with 131072 hash buckets, you shouldn't expect this many dirents per
average bucket until you have around 130 million files in a directory.

Benjamin Marzinski (2):
  gfs2: keep offset when splitting dir leaf blocks
  gfs2: change gfs2 readdir cookie

 fs/gfs2/dir.c                    | 160 ++++++++++++++++++++++++++++++---------
 fs/gfs2/incore.h                 |   3 +
 fs/gfs2/ops_fstype.c             |   3 +
 fs/gfs2/super.c                  |  12 +++
 include/uapi/linux/gfs2_ondisk.h |   9 ++-
 5 files changed, 148 insertions(+), 39 deletions(-)

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1.8.3.1