---
 fs/ext4/ext4.h         |    6 +++++
 fs/ext4/ext4_extents.h |   10 +++++++++
 fs/ext4/ext4_jbd2.h    |    3 ++
 fs/ext4/extents.c      |   50 +++++++++++++++++++++++++++++++++++++++++++++++++
 fs/ext4/super.c        |   12 +++++++++++
 5 files changed, 81 insertions(+)

--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1826,6 +1829,9 @@ extern void ext4_add_groupblocks(handle_
 				ext4_fsblk_t block, unsigned long count);
 extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);

+extern void ext4_mb_discard_inode_preallocations(struct inode *);
+
+
 /* inode.c */
 struct buffer_head *ext4_getblk(handle_t *, struct inode *,
 						ext4_lblk_t, int, int *);
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -58,6 +58,13 @@
  */
 #define EXT_STATS_

+/*
+ * define EXT4_ALLOC_NEEDED to 0 since block bitmap, group desc. and sb
+ * are now accounted in ext4_ext_calc_credits_for_insert()
+ */
+#define EXT4_ALLOC_NEEDED 0
+#define HAVE_EXT_PREPARE_CB_EXTENT
+#define HAVE_EXT4_EXT_PBLOCK

 /*
  * ext4_inode has i_block array (60 bytes total).
@@ -241,6 +248,7 @@ static inline ext4_fsblk_t ext4_ext_pblo
 	block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
 	return block;
 }
+#define ext_pblock(ex) ext4_ext_pblock(ex)

 /*
  * ext4_idx_pblock:
@@ -287,6 +295,8 @@ extern int ext4_extent_tree_init(handle_
 extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
 						   int num,
 						   struct ext4_ext_path *path);
+extern int ext4_ext_calc_credits_for_insert(struct inode *,
+					    struct ext4_ext_path *);
 extern int ext4_can_extents_be_merged(struct inode *inode,
 				      struct ext4_extent *ex1,
 				      struct ext4_extent *ex2);
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -175,6 +177,7 @@ static inline void ext4_journal_callback
 	list_del_init(&jce->jce_list);
 	spin_unlock(&sbi->s_md_lock);
 }
+#define HAVE_EXT4_JOURNAL_CALLBACK_ADD

 int
 ext4_mark_iloc_dirty(handle_t *handle,
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2205,6 +2205,56 @@ int ext4_ext_calc_credits_for_single_ext
 }

 /*
+ * This routine returns max. credits extent tree can consume.
+ * It should be OK for low-performance paths like ->writepage()
+ * To allow many writing process to fit a single transaction,
+ * caller should calculate credits under truncate_mutex and
+ * pass actual path.
+ */
+int ext4_ext_calc_credits_for_insert(struct inode *inode,
+				     struct ext4_ext_path *path)
+{
+	int depth, needed;
+
+	if (path) {
+		/* probably there is space in leaf? */
+		depth = path->p_depth;
+		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
+				< le16_to_cpu(path[depth].p_hdr->eh_max))
+			return 1;
+	}
+
+	/*
+	 * given 32bit logical block (4294967296 blocks), max. tree
+	 * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
+	 * let's also add one more level for imbalance.
+	 */
+	depth = 5;
+
+	/* allocation of new data block(s) */
+	needed = 2;
+
+	/*
+	 * tree can be full, so it'd need to grow in depth:
+	 * we need one credit to modify old root, credits for
+	 * new root will be added in split accounting
+	 */
+	needed += 1;
+	/*
+	 * Index split can happen, we'd need:
+	 *    allocate intermediate indexes (bitmap + group)
+	 *  + change two blocks at each level, but root (already included)
+	 */
+	needed += (depth * 2) + (depth * 2);
+
+	/* any allocation modifies superblock */
+	needed += 1;
+
+	return needed;
+}
+EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
+
+/*
  * How many index/leaf blocks need to change/allocate to modify nrblocks?
  *
  * if nrblocks are fit in a single extent (chunk flag is 1), then