jbd2: refine waiting for shadow buffers

[karo-tx-linux.git] / fs / jbd2 / commit.c

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 7c6f7eea2316c4d13395c970978f22b19e56b1ba..d73a0d808ec1e7339a61b4296b618518df53eb70 100644 (file)
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -30,15 +30,22 @@
 #include <trace/events/jbd2.h>
 
 /*
- * Default IO end handler for temporary BJ_IO buffer_heads.
+ * IO end handler for temporary buffer_heads handling writes to the journal.
  */
 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 {
+       struct buffer_head *orig_bh = bh->b_private;
+
        BUFFER_TRACE(bh, "");
        if (uptodate)
                set_buffer_uptodate(bh);
        else
                clear_buffer_uptodate(bh);
+       if (orig_bh) {
+               clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
+               smp_mb__after_clear_bit();
+               wake_up_bit(&orig_bh->b_state, BH_Shadow);
+       }
        unlock_buffer(bh);
 }
 
@@ -832,6 +839,7 @@ start_journal_io:
                bh = jh2bh(jh);
                clear_buffer_jwrite(bh);
                J_ASSERT_BH(bh, buffer_jbddirty(bh));
+               J_ASSERT_BH(bh, !buffer_shadow(bh));
 
                /* The metadata is now released for reuse, but we need
                    to remember it against this transaction so that when
@@ -839,14 +847,6 @@ start_journal_io:
                    required. */
                JBUFFER_TRACE(jh, "file as BJ_Forget");
                jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
-               /*
-                * Wake up any transactions which were waiting for this IO to
-                * complete. The barrier must be here so that changes by
-                * jbd2_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);
        }