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/alloc.c b/fs/ocfs2/alloc.c
index d17bdc7..20538dd 100644
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -5712,7 +5712,7 @@
 		goto out;
 	}
 
-	vfs_dq_free_space_nodirty(inode,
+	dquot_free_space_nodirty(inode,
 				  ocfs2_clusters_to_bytes(inode->i_sb, len));
 
 	ret = ocfs2_remove_extent(handle, et, cpos, len, meta_ac, dealloc);
@@ -6935,7 +6935,7 @@
 		goto bail;
 	}
 
-	vfs_dq_free_space_nodirty(inode,
+	dquot_free_space_nodirty(inode,
 			ocfs2_clusters_to_bytes(osb->sb, clusters_to_del));
 	spin_lock(&OCFS2_I(inode)->ip_lock);
 	OCFS2_I(inode)->ip_clusters = le32_to_cpu(fe->i_clusters) -
@@ -7300,11 +7300,10 @@
 		unsigned int page_end;
 		u64 phys;
 
-		if (vfs_dq_alloc_space_nodirty(inode,
-				       ocfs2_clusters_to_bytes(osb->sb, 1))) {
-			ret = -EDQUOT;
+		ret = dquot_alloc_space_nodirty(inode,
+				       ocfs2_clusters_to_bytes(osb->sb, 1));
+		if (ret)
 			goto out_commit;
-		}
 		did_quota = 1;
 
 		ret = ocfs2_claim_clusters(osb, handle, data_ac, 1, &bit_off,
@@ -7380,7 +7379,7 @@
 
 out_commit:
 	if (ret < 0 && did_quota)
-		vfs_dq_free_space_nodirty(inode,
+		dquot_free_space_nodirty(inode,
 					  ocfs2_clusters_to_bytes(osb->sb, 1));
 
 	ocfs2_commit_trans(osb, handle);