X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=fs%2Fjbd%2Fcommit.c;h=17d29a83f3ed8eaf40a450231deef799b65372c0;hb=538e7bf8cfae29e1debcd16eb50f4fdfb5c5895d;hp=4bd882548c456bc496c9facab237e12445efaed1;hpb=d23b7b625ca72612b9d43b212783414e009bd5db;p=firefly-linux-kernel-4.4.55.git

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 4bd882548c45..17d29a83f3ed 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -746,8 +746,13 @@ wait_for_iobuf:
                    required. */
 		JBUFFER_TRACE(jh, "file as BJ_Forget");
 		journal_file_buffer(jh, commit_transaction, BJ_Forget);
-		/* Wake up any transactions which were waiting for this
-		   IO to complete */
+		/*
+		 * Wake up any transactions which were waiting for this
+		 * IO to complete. The barrier must be here so that changes
+		 * by journal_file_buffer() take effect before wake_up_bit()
+		 * does the waitqueue check.
+		 */
+		smp_mb();
 		wake_up_bit(&bh->b_state, BH_Unshadow);
 		JBUFFER_TRACE(jh, "brelse shadowed buffer");
 		__brelse(bh);