ext4: drop EXT4_EX_NOFREE_ON_ERR from rest of extents handling code

Drop EXT4_EX_NOFREE_ON_ERR from ext4_ext_create_new_leaf(),
ext4_split_extent(), ext4_convert_unwritten_extents_endio().

This requires fixing all of their callers to potentially
ext4_ext_find_extent() to free the struct ext4_ext_path object in case
of an error, and there are interlocking dependencies all the way up to
ext4_ext_map_blocks(), ext4_swap_extents(), and
ext4_ext_remove_space().

Once this is done, we can drop the EXT4_EX_NOFREE_ON_ERR flag since it
is no longer necessary.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: tytso

fs/ext4/ext4.h

@@ -582,7 +582,6 @@ enum {
  */
 #define EXT4_EX_NOCACHE				0x0800
 #define EXT4_EX_FORCE_CACHE			0x1000
-#define EXT4_EX_NOFREE_ON_ERR			0x2000
 
 /*
  * Flags used by ext4_free_blocks
@@ -2731,7 +2730,7 @@ extern int ext4_can_extents_be_merged(struct inode *inode,
 				      struct ext4_extent *ex1,
 				      struct ext4_extent *ex2);
 extern int ext4_ext_insert_extent(handle_t *, struct inode *,
-				  struct ext4_ext_path *,
+				  struct ext4_ext_path **,
 				  struct ext4_extent *, int);
 extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
 						  struct ext4_ext_path **,