---
 fs/ext4/ext4.h         |    1 +
 fs/ext4/ext4_extents.h |    5 +++++
 fs/ext4/extents.c      |    2 ++
 3 files changed, 8 insertions(+)

--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -821,6 +821,7 @@ struct ext4_inode_info {
 	struct inode vfs_inode;
 	struct jbd2_inode *jinode;
 
+	unsigned long i_ext_generation;
 	struct ext4_ext_cache i_cached_extent;
 	/*
 	 * File creation time. Its function is same as that of
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -193,6 +193,11 @@ static inline unsigned short ext_depth(s
 	return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
 }
 
+static inline void ext4_ext_tree_changed(struct inode *inode)
+{
+	EXT4_I(inode)->i_ext_generation++;
+}
+
 static inline void
 ext4_ext_invalidate_cache(struct inode *inode)
 {
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -1874,6 +1874,7 @@ cleanup:
 		ext4_ext_drop_refs(npath);
 		kfree(npath);
 	}
+	ext4_ext_tree_changed(inode);
 	ext4_ext_invalidate_cache(inode);
 	return err;
 }
@@ -2681,6 +2682,7 @@ again:
 		}
 	}
 out:
+	ext4_ext_tree_changed(inode);
 	ext4_ext_drop_refs(path);
 	kfree(path);
 	if (err == -EAGAIN)