dquot: cleanup space allocation / freeing routines

Get rid of the alloc_space, free_space, reserve_space, claim_space and
release_rsv dquot operations - they are always called from the filesystem
and if a filesystem really needs their own (which none currently does)
it can just call into it's own routine directly.

Move shared logic into the common __dquot_alloc_space,
dquot_claim_space_nodirty and __dquot_free_space low-level methods,
and rationalize the wrappers around it to move as much as possible
code into the common block for CONFIG_QUOTA vs not.  Also rename
all these helpers to be named dquot_* instead of vfs_dq_*.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 558ce03..6cf3d8d 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -629,11 +629,10 @@
 	}
 
 restarted_transaction:
-	if (vfs_dq_alloc_space_nodirty(inode, ocfs2_clusters_to_bytes(osb->sb,
-	    clusters_to_add))) {
-		status = -EDQUOT;
+	status = dquot_alloc_space_nodirty(inode,
+			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
+	if (status)
 		goto leave;
-	}
 	did_quota = 1;
 
 	/* reserve a write to the file entry early on - that we if we
@@ -674,7 +673,7 @@
 	clusters_to_add -= (OCFS2_I(inode)->ip_clusters - prev_clusters);
 	spin_unlock(&OCFS2_I(inode)->ip_lock);
 	/* Release unused quota reservation */
-	vfs_dq_free_space(inode,
+	dquot_free_space(inode,
 			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
 	did_quota = 0;
 
@@ -710,7 +709,7 @@
 
 leave:
 	if (status < 0 && did_quota)
-		vfs_dq_free_space(inode,
+		dquot_free_space(inode,
 			ocfs2_clusters_to_bytes(osb->sb, clusters_to_add));
 	if (handle) {
 		ocfs2_commit_trans(osb, handle);