diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 4b7449495375..c9ea11198aa6 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -2901,9 +2901,17 @@ static int ntfs_write_mft_block(struct folio *folio, struct writeback_control *w
 	struct ntfs_inode *tni;
 	s64 lcn;
 	s64 vcn = ntfs_pidx_to_cluster(vol, folio->index);
-	s64 end_vcn = ntfs_bytes_to_cluster(vol, ni->allocated_size);
+	s64 end_vcn;
 	unsigned int folio_sz;
-	loff_t i_size = i_size_read(vi);
+	loff_t i_size;
+	s64 allocated_size;
+	unsigned long flags;
+
+	read_lock_irqsave(&ni->size_lock, flags);
+	i_size = i_size_read(vi);
+	allocated_size = ni->allocated_size;
+	read_unlock_irqrestore(&ni->size_lock, flags);
+	end_vcn = ntfs_bytes_to_cluster(vol, allocated_size);
 
 	ntfs_debug("Entering for inode 0x%llx, attribute type 0x%x, folio index 0x%lx.",
 			ni->mft_no, ni->type, folio->index);