ext4: remove do_blk_alloc()

The convenience function do_blk_alloc() is a static function with only
one caller, so fold it into ext4_new_meta_blocks() to simplify the
code and to make it easier to understand.

To save more stack space, if count is a null pointer in
ext4_new_meta_blocks() assume that caller wanted a single block (and
if there is an error, no blocks were allocated).

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e5b169b44..59401d0 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -189,10 +189,9 @@
 			struct ext4_extent *ex, int *err)
 {
 	ext4_fsblk_t goal, newblock;
-	unsigned long count = 1;
 
 	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
-	newblock = ext4_new_meta_blocks(handle, inode, goal, &count, err);
+	newblock = ext4_new_meta_blocks(handle, inode, goal, NULL, err);
 	return newblock;
 }