[GFS2] Further updates to dir and logging code

This reduces the size of the directory code by about 3k and gets
readdir() to use the functions which were introduced in the previous
directory code update.

Two memory allocations are merged into one. Eliminates zeroing of some
buffers which were never used before they were initialised by
other data.

There is still scope for further improvement in the directory code.

On the logging side, a hand created mutex has been replaced by a
standard Linux mutex in the log allocation code.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/ops_export.c b/fs/gfs2/ops_export.c
index b27bce7..be16c68 100644
--- a/fs/gfs2/ops_export.c
+++ b/fs/gfs2/ops_export.c
@@ -13,6 +13,7 @@
 #include <linux/completion.h>
 #include <linux/buffer_head.h>
 #include <linux/gfs2_ondisk.h>
+#include <linux/crc32.h>
 #include <asm/semaphore.h>
 
 #include "gfs2.h"
@@ -153,7 +154,7 @@
 	if (error)
 		return error;
 
-	error = gfs2_dir_read(dip, &offset, &gnfd, get_name_filldir);
+	error = gfs2_dir_read(dir, &offset, &gnfd, get_name_filldir);
 
 	gfs2_glock_dq_uninit(&gh);
 
@@ -165,12 +166,11 @@
 
 static struct dentry *gfs2_get_parent(struct dentry *child)
 {
-	struct qstr dotdot = { .name = "..", .len = 2 };
+	struct qstr dotdot;
 	struct inode *inode;
 	struct dentry *dentry;
 
-	dotdot.hash = gfs2_disk_hash(dotdot.name, dotdot.len);
-
+	gfs2_str2qstr(&dotdot, "..");
 	inode = gfs2_lookupi(child->d_inode, &dotdot, 1, NULL);
 
 	if (!inode)