linux-ext4 - [PATCH 2/2] jbd2: fold __wait_cp_io into jbd2_log_do

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Message-Id: <1409624051-6902-2-git-send-email-tytso@mit.edu>
Date:	Mon,  1 Sep 2014 22:14:11 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	Theodore Ts'o <tytso@....edu>
Subject: [PATCH 2/2] jbd2: fold __wait_cp_io into jbd2_log_do_checkpoint()

__wait_cp_io() is only called by jbd2_log_do_checkpoint().  Fold it in
to make it a bit easier to understand.

Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 fs/jbd2/checkpoint.c | 87 +++++++++++++++++++---------------------------------
 1 file changed, 31 insertions(+), 56 deletions(-)

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 993a187..22fcd50 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -183,58 +183,6 @@ void __jbd2_log_wait_for_space(journal_t *journal)
 	}
 }
 
-/*
- * Clean up transaction's list of buffers submitted for io.
- * We wait for any pending IO to complete and remove any clean
- * buffers. Note that we take the buffers in the opposite ordering
- * from the one in which they were submitted for IO.
- *
- * Return 0 on success, and return <0 if some buffers have failed
- * to be written out.
- *
- * Called with j_list_lock held.
- */
-static int __wait_cp_io(journal_t *journal, transaction_t *transaction)
-{
-	struct journal_head *jh;
-	struct buffer_head *bh;
-	tid_t this_tid;
-	int released = 0;
-	int ret = 0;
-
-	this_tid = transaction->t_tid;
-restart:
-	/* Did somebody clean up the transaction in the meanwhile? */
-	if (journal->j_checkpoint_transactions != transaction ||
-			transaction->t_tid != this_tid)
-		return ret;
-	while (!released && transaction->t_checkpoint_io_list) {
-		jh = transaction->t_checkpoint_io_list;
-		bh = jh2bh(jh);
-		get_bh(bh);
-		if (buffer_locked(bh)) {
-			spin_unlock(&journal->j_list_lock);
-			wait_on_buffer(bh);
-			/* the journal_head may have gone by now */
-			BUFFER_TRACE(bh, "brelse");
-			__brelse(bh);
-			spin_lock(&journal->j_list_lock);
-			goto restart;
-		}
-		if (unlikely(buffer_write_io_error(bh)))
-			ret = -EIO;
-
-		/*
-		 * Now in whatever state the buffer currently is, we know that
-		 * it has been written out and so we can drop it from the list
-		 */
-		released = __jbd2_journal_remove_checkpoint(jh);
-		__brelse(bh);
-	}
-
-	return ret;
-}
-
 static void
 __flush_batch(journal_t *journal, int *batch_count)
 {
@@ -268,7 +216,7 @@ int jbd2_log_do_checkpoint(journal_t *journal)
 	struct buffer_head	*bh;
 	transaction_t		*transaction;
 	tid_t			this_tid;
-	int			err, result, batch_count = 0;
+	int			result, batch_count = 0, done = 0;
 
 	jbd_debug(1, "Start checkpoint\n");
 
@@ -384,9 +332,36 @@ restart:
 	 * Now we issued all of the transaction's buffers, let's deal
 	 * with the buffers that are out for I/O.
 	 */
-	err = __wait_cp_io(journal, transaction);
-	if (!result)
-		result = err;
+restart2:
+	/* Did somebody clean up the transaction in the meanwhile? */
+	if (journal->j_checkpoint_transactions != transaction ||
+	    transaction->t_tid != this_tid)
+		goto out;
+
+	while (!done && transaction->t_checkpoint_io_list) {
+		jh = transaction->t_checkpoint_io_list;
+		bh = jh2bh(jh);
+		get_bh(bh);
+		if (buffer_locked(bh)) {
+			spin_unlock(&journal->j_list_lock);
+			wait_on_buffer(bh);
+			/* the journal_head may have gone by now */
+			BUFFER_TRACE(bh, "brelse");
+			__brelse(bh);
+			spin_lock(&journal->j_list_lock);
+			goto restart2;
+		}
+		if (unlikely(buffer_write_io_error(bh)) && !result)
+			result = -EIO;
+
+		/*
+		 * Now in whatever state the buffer currently is, we
+		 * know that it has been written out and so we can
+		 * drop it from the list
+		 */
+		done = __jbd2_journal_remove_checkpoint(jh);
+		__brelse(bh);
+	}
 out:
 	spin_unlock(&journal->j_list_lock);
 	if (result < 0)
-- 
2.1.0

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