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/reiserfs/stree.c b/fs/reiserfs/stree.c
index 5fa7118..313d39d 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1299,7 +1299,7 @@
 		       "reiserquota delete_item(): freeing %u, id=%u type=%c",
 		       quota_cut_bytes, inode->i_uid, head2type(&s_ih));
 #endif
-	vfs_dq_free_space_nodirty(inode, quota_cut_bytes);
+	dquot_free_space_nodirty(inode, quota_cut_bytes);
 
 	/* Return deleted body length */
 	return ret_value;
@@ -1383,7 +1383,7 @@
 					       quota_cut_bytes, inode->i_uid,
 					       key2type(key));
 #endif
-				vfs_dq_free_space_nodirty(inode,
+				dquot_free_space_nodirty(inode,
 							 quota_cut_bytes);
 			}
 			break;
@@ -1733,7 +1733,7 @@
 		       "reiserquota cut_from_item(): freeing %u id=%u type=%c",
 		       quota_cut_bytes, inode->i_uid, '?');
 #endif
-	vfs_dq_free_space_nodirty(inode, quota_cut_bytes);
+	dquot_free_space_nodirty(inode, quota_cut_bytes);
 	return ret_value;
 }
 
@@ -1968,9 +1968,10 @@
 		       key2type(&(key->on_disk_key)));
 #endif
 
-	if (vfs_dq_alloc_space_nodirty(inode, pasted_size)) {
+	retval = dquot_alloc_space_nodirty(inode, pasted_size);
+	if (retval) {
 		pathrelse(search_path);
-		return -EDQUOT;
+		return retval;
 	}
 	init_tb_struct(th, &s_paste_balance, th->t_super, search_path,
 		       pasted_size);
@@ -2024,7 +2025,7 @@
 		       pasted_size, inode->i_uid,
 		       key2type(&(key->on_disk_key)));
 #endif
-	vfs_dq_free_space_nodirty(inode, pasted_size);
+	dquot_free_space_nodirty(inode, pasted_size);
 	return retval;
 }
 
@@ -2062,9 +2063,10 @@
 #endif
 		/* We can't dirty inode here. It would be immediately written but
 		 * appropriate stat item isn't inserted yet... */
-		if (vfs_dq_alloc_space_nodirty(inode, quota_bytes)) {
+		retval = dquot_alloc_space_nodirty(inode, quota_bytes);
+		if (retval) {
 			pathrelse(path);
-			return -EDQUOT;
+			return retval;
 		}
 	}
 	init_tb_struct(th, &s_ins_balance, th->t_super, path,
@@ -2113,6 +2115,6 @@
 		       quota_bytes, inode->i_uid, head2type(ih));
 #endif
 	if (inode)
-		vfs_dq_free_space_nodirty(inode, quota_bytes);
+		dquot_free_space_nodirty(inode, quota_bytes);
 	return retval;
 }