From aeda7f6343e6375a832e52ff5ed389c115023ca5 Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Date: Mon, 2 Nov 2009 15:08:13 +0900
Subject: [PATCH] nilfs2: fix irregular checkpoint creation due to data flush

When nilfs flushes out dirty data to reduce memory pressure, creation
of checkpoints is wrongly postponed.  This bug causes irregular
checkpoint creation especially in small footprint systems.

To correct this issue, a timer for the checkpoint creation has to be
continued if a log writer does not create a checkpoint.

This will do the correction.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
---
 fs/nilfs2/segment.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 683df89dbae5a..6eff66a070d5e 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2468,17 +2468,22 @@ static void nilfs_segctor_notify(struct nilfs_sc_info *sci,
 	/* Clear requests (even when the construction failed) */
 	spin_lock(&sci->sc_state_lock);
 
-	sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
-
 	if (req->mode == SC_LSEG_SR) {
+		sci->sc_state &= ~NILFS_SEGCTOR_COMMIT;
 		sci->sc_seq_done = req->seq_accepted;
 		nilfs_segctor_wakeup(sci, req->sc_err ? : req->sb_err);
 		sci->sc_flush_request = 0;
-	} else if (req->mode == SC_FLUSH_FILE)
-		sci->sc_flush_request &= ~FLUSH_FILE_BIT;
-	else if (req->mode == SC_FLUSH_DAT)
-		sci->sc_flush_request &= ~FLUSH_DAT_BIT;
+	} else {
+		if (req->mode == SC_FLUSH_FILE)
+			sci->sc_flush_request &= ~FLUSH_FILE_BIT;
+		else if (req->mode == SC_FLUSH_DAT)
+			sci->sc_flush_request &= ~FLUSH_DAT_BIT;
 
+		/* re-enable timer if checkpoint creation was not done */
+		if (sci->sc_timer && (sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
+		    time_before(jiffies, sci->sc_timer->expires))
+			add_timer(sci->sc_timer);
+	}
 	spin_unlock(&sci->sc_state_lock);
 }
 
-- 
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