fs: Convert nr_inodes and nr_unused to per-cpu counters

The number of inodes allocated does not need to be tied to the
addition or removal of an inode to/from a list. If we are not tied
to a list lock, we could update the counters when inodes are
initialised or destroyed, but to do that we need to convert the
counters to be per-cpu (i.e. independent of a lock). This means that
we have the freedom to change the list/locking implementation
without needing to care about the counters.

Based on a patch originally from Eric Dumazet.

[AV: cleaned up a bit, fixed build breakage on weird configs

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 694b140852c2..99a510cbfbb3 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1340,14 +1340,14 @@ static struct ctl_table fs_table[] = {
                 .data           = &inodes_stat,
                 .maxlen         = 2*sizeof(int),
                 .mode           = 0444,
-                .proc_handler   = proc_dointvec,
+                .proc_handler   = proc_nr_inodes,
         },
         {
                 .procname       = "inode-state",
                 .data           = &inodes_stat,
                 .maxlen         = 7*sizeof(int),
                 .mode           = 0444,
-                .proc_handler   = proc_dointvec,
+                .proc_handler   = proc_nr_inodes,
         },
         {
                 .procname       = "file-nr",