jbd2: Modify ASYNC_COMMIT code to not rely on queue draining on barrier

Currently JBD2 relies blkdev_issue_flush() draining the queue when ASYNC_COMMIT
feature is set. This property is going away so make JBD2 wait for buffers it
needs on its own before submitting the cache flush.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 16 insertions, 13 deletions

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 7c068c189d80..d6aeb1f6cfe0 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -701,6 +701,16 @@ start_journal_io:
                 }
         }
 
+        err = journal_finish_inode_data_buffers(journal, commit_transaction);
+        if (err) {
+                printk(KERN_WARNING
+                        "JBD2: Detected IO errors while flushing file data "
+                       "on %s\n", journal->j_devname);
+                if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
+                        jbd2_journal_abort(journal, err);
+                err = 0;
+        }
+
         /* 
          * If the journal is not located on the file system device,
          * then we must flush the file system device before we issue
@@ -719,19 +729,6 @@ start_journal_io:
                                                  &cbh, crc32_sum);
                 if (err)
                         __jbd2_journal_abort_hard(journal);
-                if (journal->j_flags & JBD2_BARRIER)
-                        blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL,
-                                BLKDEV_IFL_WAIT);
-        }
-
-        err = journal_finish_inode_data_buffers(journal, commit_transaction);
-        if (err) {
-                printk(KERN_WARNING
-                        "JBD2: Detected IO errors while flushing file data "
-                       "on %s\n", journal->j_devname);
-                if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
-                        jbd2_journal_abort(journal, err);
-                err = 0;
         }
 
         /* Lo and behold: we have just managed to send a transaction to
@@ -845,6 +842,12 @@ wait_for_iobuf:
         }
         if (!err && !is_journal_aborted(journal))
                 err = journal_wait_on_commit_record(journal, cbh);
+        if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+                                      JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
+            journal->j_flags & JBD2_BARRIER) {
+                blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL,
+                                   BLKDEV_IFL_WAIT);
+        }
 
         if (err)
                 jbd2_journal_abort(journal, err);