diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 3dca526..9b82ac7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -47,6 +47,7 @@
 #include "xattr.h"
 #include "acl.h"
 #include "ext4_extents.h"
+#include "truncate.h"
 
 #include <trace/events/ext4.h>
 
@@ -89,33 +90,6 @@
 }
 
 /*
- * Work out how many blocks we need to proceed with the next chunk of a
- * truncate transaction.
- */
-static unsigned long blocks_for_truncate(struct inode *inode)
-{
-	ext4_lblk_t needed;
-
-	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
-
-	/* Give ourselves just enough room to cope with inodes in which
-	 * i_blocks is corrupt: we've seen disk corruptions in the past
-	 * which resulted in random data in an inode which looked enough
-	 * like a regular file for ext4 to try to delete it.  Things
-	 * will go a bit crazy if that happens, but at least we should
-	 * try not to panic the whole kernel. */
-	if (needed < 2)
-		needed = 2;
-
-	/* But we need to bound the transaction so we don't overflow the
-	 * journal. */
-	if (needed > EXT4_MAX_TRANS_DATA)
-		needed = EXT4_MAX_TRANS_DATA;
-
-	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
-}
-
-/*
  * Truncate transactions can be complex and absolutely huge.  So we need to
  * be able to restart the transaction at a conventient checkpoint to make
  * sure we don't overflow the journal.
@@ -129,7 +103,7 @@
 {
 	handle_t *result;
 
-	result = ext4_journal_start(inode, blocks_for_truncate(inode));
+	result = ext4_journal_start(inode, ext4_blocks_for_truncate(inode));
 	if (!IS_ERR(result))
 		return result;
 
@@ -149,7 +123,7 @@
 		return 0;
 	if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
 		return 0;
-	if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
+	if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode)))
 		return 0;
 	return 1;
 }
@@ -204,7 +178,7 @@
 	if (is_bad_inode(inode))
 		goto no_delete;
 
-	handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
+	handle = ext4_journal_start(inode, ext4_blocks_for_truncate(inode)+3);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -1555,16 +1529,6 @@
 	return ret;
 }
 
-/*
- * Truncate blocks that were not used by write. We have to truncate the
- * pagecache as well so that corresponding buffers get properly unmapped.
- */
-static void ext4_truncate_failed_write(struct inode *inode)
-{
-	truncate_inode_pages(inode->i_mapping, inode->i_size);
-	ext4_truncate(inode);
-}
-
 static int ext4_get_block_write(struct inode *inode, sector_t iblock,
 		   struct buffer_head *bh_result, int create);
 static int ext4_write_begin(struct file *file, struct address_space *mapping,
@@ -4134,7 +4098,7 @@
 		if (unlikely(err))
 			goto out_err;
 		err = ext4_truncate_restart_trans(handle, inode,
-						  blocks_for_truncate(inode));
+					ext4_blocks_for_truncate(inode));
 		if (unlikely(err))
 			goto out_err;
 		if (bh) {
@@ -4329,7 +4293,7 @@
 			if (try_to_extend_transaction(handle, inode)) {
 				ext4_mark_inode_dirty(handle, inode);
 				ext4_truncate_restart_trans(handle, inode,
-					    blocks_for_truncate(inode));
+					    ext4_blocks_for_truncate(inode));
 			}
 
 			/*
diff --git a/fs/ext4/truncate.h b/fs/ext4/truncate.h
new file mode 100644
index 0000000..011ba66
--- /dev/null
+++ b/fs/ext4/truncate.h
@@ -0,0 +1,43 @@
+/*
+ * linux/fs/ext4/truncate.h
+ *
+ * Common inline functions needed for truncate support
+ */
+
+/*
+ * Truncate blocks that were not used by write. We have to truncate the
+ * pagecache as well so that corresponding buffers get properly unmapped.
+ */
+static inline void ext4_truncate_failed_write(struct inode *inode)
+{
+	truncate_inode_pages(inode->i_mapping, inode->i_size);
+	ext4_truncate(inode);
+}
+
+/*
+ * Work out how many blocks we need to proceed with the next chunk of a
+ * truncate transaction.
+ */
+static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
+{
+	ext4_lblk_t needed;
+
+	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
+
+	/* Give ourselves just enough room to cope with inodes in which
+	 * i_blocks is corrupt: we've seen disk corruptions in the past
+	 * which resulted in random data in an inode which looked enough
+	 * like a regular file for ext4 to try to delete it.  Things
+	 * will go a bit crazy if that happens, but at least we should
+	 * try not to panic the whole kernel. */
+	if (needed < 2)
+		needed = 2;
+
+	/* But we need to bound the transaction so we don't overflow the
+	 * journal. */
+	if (needed > EXT4_MAX_TRANS_DATA)
+		needed = EXT4_MAX_TRANS_DATA;
+
+	return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
+}
+