jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging

'write_op' was still used, even though it was always WRITE_SYNC now.
Add plugging around the cases where it submits IO, and flush them
before we end up waiting for that IO.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 3da1cc4..fa36d76 100644 (file)
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -329,7 +329,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
        int tag_bytes = journal_tag_bytes(journal);
        struct buffer_head *cbh = NULL; /* For transactional checksums */
        __u32 crc32_sum = ~0;
-       int write_op = WRITE_SYNC;
+       struct blk_plug plug;
 
        /*
         * First job: lock down the current transaction and wait for
@@ -363,13 +363,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
        write_lock(&journal->j_state_lock);
        commit_transaction->t_state = T_LOCKED;
 
-       /*
-        * Use plugged writes here, since we want to submit several before
-        * we unplug the device. We don't do explicit unplugging in here,
-        * instead we rely on sync_buffer() doing the unplug for us.
-        */
-       if (commit_transaction->t_synchronous_commit)
-               write_op = WRITE_SYNC;
        trace_jbd2_commit_locking(journal, commit_transaction);
        stats.run.rs_wait = commit_transaction->t_max_wait;
        stats.run.rs_locked = jiffies;
@@ -469,8 +462,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
        if (err)
                jbd2_journal_abort(journal, err);
 
+       blk_start_plug(&plug);
        jbd2_journal_write_revoke_records(journal, commit_transaction,
-                                         write_op);
+                                         WRITE_SYNC);
+       blk_finish_plug(&plug);
 
        jbd_debug(3, "JBD: commit phase 2\n");
 
@@ -497,6 +492,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
        err = 0;
        descriptor = NULL;
        bufs = 0;
+       blk_start_plug(&plug);
        while (commit_transaction->t_buffers) {
 
                /* Find the next buffer to be journaled... */
@@ -658,7 +654,7 @@ start_journal_io:
                                clear_buffer_dirty(bh);
                                set_buffer_uptodate(bh);
                                bh->b_end_io = journal_end_buffer_io_sync;
-                               submit_bh(write_op, bh);
+                               submit_bh(WRITE_SYNC, bh);
                        }
                        cond_resched();
                        stats.run.rs_blocks_logged += bufs;
@@ -699,6 +695,8 @@ start_journal_io:
                        __jbd2_journal_abort_hard(journal);
        }
 
+       blk_finish_plug(&plug);
+
        /* Lo and behold: we have just managed to send a transaction to
            the log.  Before we can commit it, wait for the IO so far to
            complete.  Control buffers being written are on the