jbd2: fix sending of data flush on journal commit

In data=ordered mode, it's theoretically possible (however rare) that
an inode is filed to transaction's t_inode_list and a flusher thread
writes all the data and inode is reclaimed before the transaction
starts to commit.  In such a case, we could erroneously omit sending a
flush to file system device when it is different from the journal
device (because data can still be in disk cache only).

Fix the problem by setting a flag in a transaction when some inode is added
to it and then send disk flush in the commit code when the flag is set.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index a32dcaec04e1..4d57955061f4 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -658,7 +658,9 @@ struct transaction_s
          * waiting for it to finish.
          */
         unsigned int t_synchronous_commit:1;
-        unsigned int t_flushed_data_blocks:1;
+
+        /* Disk flush needs to be sent to fs partition [no locking] */
+        int                     t_need_data_flush;
 
         /*
          * For use by the filesystem to store fs-specific data