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>

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 7c068c1..d6aeb1f 100644 (file)
--- 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);