ext4: Add new tracepoints to debug delayed allocation space functions

Add tracepoints for ext4_da_reserve_space(),
ext4_da_update_reserve_space(), and ext4_da_release_space().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3e8afd9..1a3d7b2 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1061,6 +1061,7 @@
 	int mdb_free = 0, allocated_meta_blocks = 0;
 
 	spin_lock(&ei->i_block_reservation_lock);
+	trace_ext4_da_update_reserve_space(inode, used);
 	if (unlikely(used > ei->i_reserved_data_blocks)) {
 		ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, used %d "
 			 "with only %d reserved data blocks\n",
@@ -1846,6 +1847,7 @@
 	spin_lock(&ei->i_block_reservation_lock);
 	md_reserved = ei->i_reserved_meta_blocks;
 	md_needed = ext4_calc_metadata_amount(inode, lblock);
+	trace_ext4_da_reserve_space(inode, md_needed);
 	spin_unlock(&ei->i_block_reservation_lock);
 
 	/*