GFS2: Merge lock_dlm module into GFS2

This is the big patch that I've been working on for some time
now. There are many reasons for wanting to make this change
such as:
 o Reducing overhead by eliminating duplicated fields between structures
 o Simplifcation of the code (reduces the code size by a fair bit)
 o The locking interface is now the DLM interface itself as proposed
   some time ago.
 o Fewer lookups of glocks when processing replies from the DLM
 o Fewer memory allocations/deallocations for each glock
 o Scope to do further optimisations in the future (but this patch is
   more than big enough for now!)

Please note that (a) this patch relates to the lock_dlm module and
not the DLM itself, that is still a separate module; and (b) that
we retain the ability to build GFS2 as a standalone single node
filesystem with out requiring the DLM.

This patch needs a lot of testing, hence my keeping it I restarted
my -git tree after the last merge window. That way, this has the maximum
exposure before its merged. This is (modulo a few minor bug fixes) the
same patch that I've been posting on and off the the last three months
and its passed a number of different tests so far.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/fs/gfs2/Kconfig b/fs/gfs2/Kconfig
index e563a6449811..3a981b7f64ca 100644
--- a/fs/gfs2/Kconfig
+++ b/fs/gfs2/Kconfig
@@ -1,6 +1,10 @@
 config GFS2_FS
         tristate "GFS2 file system support"
         depends on EXPERIMENTAL && (64BIT || LBD)
+        select DLM if GFS2_FS_LOCKING_DLM
+        select CONFIGFS_FS if GFS2_FS_LOCKING_DLM
+        select SYSFS if GFS2_FS_LOCKING_DLM
+        select IP_SCTP if DLM_SCTP
         select FS_POSIX_ACL
         select CRC32
         help
@@ -18,17 +22,16 @@ config GFS2_FS
           the locking module below. Documentation and utilities for GFS2 can
           be found here: http://sources.redhat.com/cluster
 
-          The "nolock" lock module is now built in to GFS2 by default.
+          The "nolock" lock module is now built in to GFS2 by default. If
+          you want to use the DLM, be sure to enable HOTPLUG and IPv4/6
+          networking.
 
 config GFS2_FS_LOCKING_DLM
-        tristate "GFS2 DLM locking module"
-        depends on GFS2_FS && SYSFS && NET && INET && (IPV6 || IPV6=n)
-        select IP_SCTP if DLM_SCTP
-        select CONFIGFS_FS
-        select DLM
+        bool "GFS2 DLM locking"
+        depends on (GFS2_FS!=n) && NET && INET && (IPV6 || IPV6=n) && HOTPLUG
         help
           Multiple node locking module for GFS2
 
-          Most users of GFS2 will require this module. It provides the locking
+          Most users of GFS2 will require this. It provides the locking
           interface between GFS2 and the DLM, which is required to use GFS2
           in a cluster environment.