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, 18 insertions, 4 deletions

diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index d5329364cdff..dca4fee3078b 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -101,12 +101,26 @@ void gfs2_dinode_print(const struct gfs2_inode *ip);
 extern const struct inode_operations gfs2_file_iops;
 extern const struct inode_operations gfs2_dir_iops;
 extern const struct inode_operations gfs2_symlink_iops;
-extern const struct file_operations gfs2_file_fops;
-extern const struct file_operations gfs2_dir_fops;
-extern const struct file_operations gfs2_file_fops_nolock;
-extern const struct file_operations gfs2_dir_fops_nolock;
+extern const struct file_operations *gfs2_file_fops_nolock;
+extern const struct file_operations *gfs2_dir_fops_nolock;
 
 extern void gfs2_set_inode_flags(struct inode *inode);
+ 
+#ifdef CONFIG_GFS2_FS_LOCKING_DLM
+extern const struct file_operations *gfs2_file_fops;
+extern const struct file_operations *gfs2_dir_fops;
+static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
+{
+	return sdp->sd_args.ar_localflocks;
+}
+#else /* Single node only */
+#define gfs2_file_fops NULL
+#define gfs2_dir_fops NULL
+static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
+{
+	return 1;
+}
+#endif /* CONFIG_GFS2_FS_LOCKING_DLM */
 
 #endif /* __INODE_DOT_H__ */