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, 22 insertions, 52 deletions

diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index 93fe41b..99d726f 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -20,9 +20,10 @@
 #include <linux/gfs2_ondisk.h>
 #include <linux/ext2_fs.h>
 #include <linux/crc32.h>
-#include <linux/lm_interface.h>
 #include <linux/writeback.h>
 #include <asm/uaccess.h>
+#include <linux/dlm.h>
+#include <linux/dlm_plock.h>
 
 #include "gfs2.h"
 #include "incore.h"
@@ -560,57 +561,24 @@ static int gfs2_fsync(struct file *file, struct dentry *dentry, int datasync)
 	return ret;
 }
 
+#ifdef CONFIG_GFS2_FS_LOCKING_DLM
+
 /**
  * gfs2_setlease - acquire/release a file lease
  * @file: the file pointer
  * @arg: lease type
  * @fl: file lock
  *
+ * We don't currently have a way to enforce a lease across the whole
+ * cluster; until we do, disable leases (by just returning -EINVAL),
+ * unless the administrator has requested purely local locking.
+ *
  * Returns: errno
  */
 
 static int gfs2_setlease(struct file *file, long arg, struct file_lock **fl)
 {
-	struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
-
-	/*
-	 * We don't currently have a way to enforce a lease across the whole
-	 * cluster; until we do, disable leases (by just returning -EINVAL),
-	 * unless the administrator has requested purely local locking.
-	 */
-	if (!sdp->sd_args.ar_localflocks)
-		return -EINVAL;
-	return generic_setlease(file, arg, fl);
-}
-
-static int gfs2_lm_plock_get(struct gfs2_sbd *sdp, struct lm_lockname *name,
-		      struct file *file, struct file_lock *fl)
-{
-	int error = -EIO;
-	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-		error = sdp->sd_lockstruct.ls_ops->lm_plock_get(
-				sdp->sd_lockstruct.ls_lockspace, name, file, fl);
-	return error;
-}
-
-static int gfs2_lm_plock(struct gfs2_sbd *sdp, struct lm_lockname *name,
-		  struct file *file, int cmd, struct file_lock *fl)
-{
-	int error = -EIO;
-	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-		error = sdp->sd_lockstruct.ls_ops->lm_plock(
-				sdp->sd_lockstruct.ls_lockspace, name, file, cmd, fl);
-	return error;
-}
-
-static int gfs2_lm_punlock(struct gfs2_sbd *sdp, struct lm_lockname *name,
-		    struct file *file, struct file_lock *fl)
-{
-	int error = -EIO;
-	if (likely(!test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
-		error = sdp->sd_lockstruct.ls_ops->lm_punlock(
-				sdp->sd_lockstruct.ls_lockspace, name, file, fl);
-	return error;
+	return -EINVAL;
 }
 
 /**
@@ -626,9 +594,7 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
 {
 	struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 	struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
-	struct lm_lockname name =
-		{ .ln_number = ip->i_no_addr,
-		  .ln_type = LM_TYPE_PLOCK };
+	struct lm_lockstruct *ls = &sdp->sd_lockstruct;
 
 	if (!(fl->fl_flags & FL_POSIX))
 		return -ENOLCK;
@@ -640,12 +606,14 @@ static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
 		cmd = F_SETLK;
 		fl->fl_type = F_UNLCK;
 	}
+	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
+		return -EIO;
 	if (IS_GETLK(cmd))
-		return gfs2_lm_plock_get(sdp, &name, file, fl);
+		return dlm_posix_get(ls->ls_dlm, ip->i_no_addr, file, fl);
 	else if (fl->fl_type == F_UNLCK)
-		return gfs2_lm_punlock(sdp, &name, file, fl);
+		return dlm_posix_unlock(ls->ls_dlm, ip->i_no_addr, file, fl);
 	else
-		return gfs2_lm_plock(sdp, &name, file, cmd, fl);
+		return dlm_posix_lock(ls->ls_dlm, ip->i_no_addr, file, cmd, fl);
 }
 
 static int do_flock(struct file *file, int cmd, struct file_lock *fl)
@@ -732,7 +700,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
 	}
 }
 
-const struct file_operations gfs2_file_fops = {
+const struct file_operations *gfs2_file_fops = &(const struct file_operations){
 	.llseek		= gfs2_llseek,
 	.read		= do_sync_read,
 	.aio_read	= generic_file_aio_read,
@@ -750,7 +718,7 @@ const struct file_operations gfs2_file_fops = {
 	.setlease	= gfs2_setlease,
 };
 
-const struct file_operations gfs2_dir_fops = {
+const struct file_operations *gfs2_dir_fops = &(const struct file_operations){
 	.readdir	= gfs2_readdir,
 	.unlocked_ioctl	= gfs2_ioctl,
 	.open		= gfs2_open,
@@ -760,7 +728,9 @@ const struct file_operations gfs2_dir_fops = {
 	.flock		= gfs2_flock,
 };
 
-const struct file_operations gfs2_file_fops_nolock = {
+#endif /* CONFIG_GFS2_FS_LOCKING_DLM */
+
+const struct file_operations *gfs2_file_fops_nolock = &(const struct file_operations){
 	.llseek		= gfs2_llseek,
 	.read		= do_sync_read,
 	.aio_read	= generic_file_aio_read,
@@ -773,10 +743,10 @@ const struct file_operations gfs2_file_fops_nolock = {
 	.fsync		= gfs2_fsync,
 	.splice_read	= generic_file_splice_read,
 	.splice_write	= generic_file_splice_write,
-	.setlease	= gfs2_setlease,
+	.setlease	= generic_setlease,
 };
 
-const struct file_operations gfs2_dir_fops_nolock = {
+const struct file_operations *gfs2_dir_fops_nolock = &(const struct file_operations){
 	.readdir	= gfs2_readdir,
 	.unlocked_ioctl	= gfs2_ioctl,
 	.open		= gfs2_open,