positional readdir cookies

These two patches implement positional readdir cookies. The first one simply changes how splitting leaf blocks works to allow for this method to work. The second one does the meat of the work.

Like I mention in the second patch, this adds a new parameter to the dirent structure that is never saved to disk. This is simply to make use of the memory to store the computed location based cookie. Avoiding this has a noticeable performance impact. However, I'm open to any ideas on how to make this look less strange (or, any other ways of getting space to store these values that doesn't involve allocating it, which caused the performance hit).

This set is the same as my last set but the ar_loccookie flag in gfs2_args, is now a single bit, instead of a whole unsigned int.

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