jbd: 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/jbd/commit.c b/fs/jbd/commit.c
index 66be299acb1b8d1da52365c180e821fed734ded1..da871ee084d365780f8a3f78078550e48d3f12ea 100644 (file)
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -20,6 +20,7 @@
 #include <linux/mm.h>
 #include <linux/pagemap.h>
 #include <linux/bio.h>
+#include <linux/blkdev.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -294,7 +295,7 @@ void journal_commit_transaction(journal_t *journal)
        int first_tag = 0;
        int tag_flag;
        int i;
-       int write_op = WRITE_SYNC;
+       struct blk_plug plug;
 
        /*
         * First job: lock down the current transaction and wait for
@@ -327,13 +328,6 @@ void journal_commit_transaction(journal_t *journal)
        spin_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;
        spin_lock(&commit_transaction->t_handle_lock);
        while (commit_transaction->t_updates) {
                DEFINE_WAIT(wait);
@@ -418,8 +412,10 @@ void journal_commit_transaction(journal_t *journal)
         * Now start flushing things to disk, in the order they appear
         * on the transaction lists.  Data blocks go first.
         */
+       blk_start_plug(&plug);
        err = journal_submit_data_buffers(journal, commit_transaction,
-                                         write_op);
+                                         WRITE_SYNC);
+       blk_finish_plug(&plug);
 
        /*
         * Wait for all previously submitted IO to complete.
@@ -480,7 +476,9 @@ void journal_commit_transaction(journal_t *journal)
                err = 0;
        }
 
-       journal_write_revoke_records(journal, commit_transaction, write_op);
+       blk_start_plug(&plug);
+
+       journal_write_revoke_records(journal, commit_transaction, WRITE_SYNC);
 
        /*
         * If we found any dirty or locked buffers, then we should have
@@ -650,7 +648,7 @@ 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();
 
@@ -661,6 +659,8 @@ start_journal_io:
                }
        }
 
+       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