jbd: Fix forever sleeping process in do_get_write_access()

[firefly-linux-kernel-4.4.55.git] / fs / jbd / commit.c

diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 4bd882548c456bc496c9facab237e12445efaed1..17d29a83f3ed8eaf40a450231deef799b65372c0 100644 (file)
--- 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);