ext4: fix ext4_flush_completed_IO wait semantics

[karo-tx-linux.git] / fs / ext4 / indirect.c

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 830e1b2bf145c99f1ebdc2198147295d73eff8ac..792e388e7b444bece02de64261be376227bd22bc 100644 (file)
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -807,16 +807,30 @@ ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
 
 retry:
        if (rw == READ && ext4_should_dioread_nolock(inode)) {
-               if (unlikely(!list_empty(&ei->i_completed_io_list))) {
+               if (unlikely(atomic_read(&EXT4_I(inode)->i_unwritten))) {
                        mutex_lock(&inode->i_mutex);
-                       ext4_flush_completed_IO(inode);
+                       ext4_flush_unwritten_io(inode);
                        mutex_unlock(&inode->i_mutex);
                }
+               /*
+                * 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);