1 files changed, 14 insertions, 0 deletions
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 61f13e57975e..8d849dae8428 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -810,11 +810,25 @@ retry:
 		if (unlikely(!list_empty(&ei->i_completed_io_list)))
 			ext4_flush_completed_IO(inode);
 
+		/*
+		 * Nolock dioread optimization may be dynamically disabled
+		 * via ext4_inode_block_unlocked_dio(). Check inode's state
+		 * while holding extra i_dio_count ref.
+		 */
+		atomic_inc(&inode->i_dio_count);
+		smp_mb();
+		if (unlikely(ext4_test_inode_state(inode,
+						    EXT4_STATE_DIOREAD_LOCK))) {
+			inode_dio_done(inode);
+			goto locked;
+		}
 		ret = __blockdev_direct_IO(rw, iocb, inode,
 				 inode->i_sb->s_bdev, iov,
 				 offset, nr_segs,
 				 ext4_get_block, NULL, NULL, 0);
+		inode_dio_done(inode);
 	} else {
+locked:
 		ret = blockdev_direct_IO(rw, iocb, inode, iov,
 				 offset, nr_segs, ext4_get_block);