diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 299aee4..eed073c 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -778,22 +778,26 @@ xfs_file_fallocate(
 		if (error)
 			goto out_unlock;
 	} else if (mode & FALLOC_FL_INSERT_RANGE) {
-		unsigned int blksize_mask = i_blocksize(inode) - 1;
+		unsigned int	blksize_mask = i_blocksize(inode) - 1;
+		loff_t		isize = i_size_read(inode);
 
-		new_size = i_size_read(inode) + len;
 		if (offset & blksize_mask || len & blksize_mask) {
 			error = -EINVAL;
 			goto out_unlock;
 		}
 
-		/* check the new inode size does not wrap through zero */
-		if (new_size > inode->i_sb->s_maxbytes) {
+		/*
+		 * New inode size must not exceed ->s_maxbytes, accounting for
+		 * possible signed overflow.
+		 */
+		if (inode->i_sb->s_maxbytes - isize < len) {
 			error = -EFBIG;
 			goto out_unlock;
 		}
+		new_size = isize + len;
 
 		/* Offset should be less than i_size */
-		if (offset >= i_size_read(inode)) {
+		if (offset >= isize) {
 			error = -EINVAL;
 			goto out_unlock;
 		}