[PATCH 0/4 V4] xfs: new global stats in sysfs

[Bill O'Donnell]

Hi all-

Here is a new pass at the series to add new global stats to sysfs.
The new series now includes a fourth patch that consolidates sysfs
ops for debug, stats and log. (Per Dave Chinner's suggestion to
create a common sysfs_ops structure to help streamline).

The series provides the beginnings of the infrastructure for per-fs
stats (in addition to global accumulative stats).

We already have per-fs information in /sys, so it makes sense to
have per-fs stats there too.  As a first step, moving existing
global stats infrastructure to /sys will allow us to re-use that
sysfs code for per-fs stats as well.

Patch 1 handles the bring-up and tear down of xfs/stats directory
structure in sysfs when an fs is mounted. The directory contains
the stats file and the stats_clear file. The stats file contents mimic
those of /proc/fs/xfs/stat. The stats_clear file is empty, and much
like the current stat_clear command, handles the zeroing of the stats
file when a "1" is echoed to the stats_clear file.

Patch 2 creates the symlink for stats from procfs to sysfs.

Patch 3 removes the now unused portions of procfs for stat.

Patch 4 consolidates the sysfs ops for dbg, stats, log.

Once again, comments and questions are welcome.

Thanks-
Bill