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Date: Wed, 8 Apr 2009 14:00:10 +0200
From: Jens Axboe <jens.axboe@...cle.com>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc: chris.mason@...cle.com, david@...morbit.com, hch@...radead.org,
akpm@...ux-foundation.org, jack@...e.cz,
Jens Axboe <jens.axboe@...cle.com>
Subject: [PATCH 07/13] writeback: include default_backing_dev_info in writeback
We see dirty inodes there occasionally, so better be safe and write them
out.
Signed-off-by: Jens Axboe <jens.axboe@...cle.com>
---
fs/fs-writeback.c | 60 ++++++++++++++++++++++++++------------------
include/linux/writeback.h | 1 +
mm/backing-dev.c | 31 ++++++++++++++---------
3 files changed, 55 insertions(+), 37 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 756714f..bcca7c1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -34,6 +34,10 @@
*/
int nr_pdflush_threads = 0;
+static void generic_sync_wb_inodes(struct bdi_writeback *wb,
+ struct super_block *sb,
+ struct writeback_control *wbc);
+
/**
* writeback_acquire - attempt to get exclusive writeback access to a device
* @bdi: the device's backing_dev_info structure
@@ -149,7 +153,7 @@ int bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,
* older_than_this takes precedence over nr_to_write. So we'll only write back
* all dirty pages if they are all attached to "old" mappings.
*/
-static void wb_kupdated(struct bdi_writeback *wb)
+void wb_kupdated(struct bdi_writeback *wb)
{
long nr_to_write;
struct writeback_control wbc = {
@@ -177,11 +181,7 @@ static void wb_kupdated(struct bdi_writeback *wb)
}
}
-static void generic_sync_wb_inodes(struct bdi_writeback *wb,
- struct super_block *sb,
- struct writeback_control *wbc);
-
-static void wb_writeback(struct bdi_writeback *wb)
+void wb_writeback(struct bdi_writeback *wb)
{
struct writeback_control wbc = {
.bdi = wb->bdi,
@@ -217,6 +217,34 @@ static void wb_writeback(struct bdi_writeback *wb)
}
/*
+ * This will be inlined in bdi_writeback_task() once we get rid of any
+ * dirty inodes on the default_backing_dev_info
+ */
+void wb_do_writeback(struct bdi_writeback *wb)
+{
+ /*
+ * We get here in two cases:
+ *
+ * schedule_timeout() returned because the dirty writeback
+ * interval has elapsed. If that happens, we will be able
+ * to acquire the writeback lock and will proceed to do
+ * kupdated style writeout.
+ *
+ * Someone called bdi_start_writeback(), which will acquire
+ * the writeback lock. This means our writeback_acquire()
+ * below will fail and we call into bdi_pdflush() for
+ * pdflush style writeout.
+ *
+ */
+ if (writeback_acquire(wb))
+ wb_kupdated(wb);
+ else
+ wb_writeback(wb);
+
+ writeback_release(wb);
+}
+
+/*
* Handle writeback of dirty data for the device backed by this bdi. Also
* wakes up periodically and does kupdated style flushing.
*/
@@ -231,26 +259,8 @@ int bdi_writeback_task(struct bdi_writeback *wb)
schedule_timeout(wait_jiffies);
try_to_freeze();
- /*
- * We get here in two cases:
- *
- * schedule_timeout() returned because the dirty writeback
- * interval has elapsed. If that happens, we will be able
- * to acquire the writeback lock and will proceed to do
- * kupdated style writeout.
- *
- * Someone called bdi_start_writeback(), which will acquire
- * the writeback lock. This means our writeback_acquire()
- * below will fail and we call into bdi_pdflush() for
- * pdflush style writeout.
- *
- */
- if (writeback_acquire(wb))
- wb_kupdated(wb);
- else
- wb_writeback(wb);
+ wb_do_writeback(wb);
- writeback_release(wb);
finish_wait(&wb->wait, &wait);
}
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index f241794..2e08bbd 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -69,6 +69,7 @@ void writeback_inodes(struct writeback_control *wbc);
int inode_wait(void *);
void sync_inodes_sb(struct super_block *, int wait);
void sync_inodes(int wait);
+void wb_do_writeback(struct bdi_writeback *wb);
/* writeback.h requires fs.h; it, too, is not included from here. */
static inline void wait_on_inode(struct inode *inode)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 4ebcc49..9707545 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -357,14 +357,6 @@ static int bdi_forker_task(void *ptr)
struct bdi_writeback *wb;
DEFINE_WAIT(wait);
- /*
- * Should never trigger on the default bdi
- */
- if (wb_has_dirty_io(me)) {
- bdi_flush_io(me->bdi);
- WARN_ON(1);
- }
-
prepare_to_wait(&me->wait, &wait, TASK_INTERRUPTIBLE);
smp_mb();
@@ -372,6 +364,21 @@ static int bdi_forker_task(void *ptr)
schedule();
finish_wait(&me->wait, &wait);
+
+ /*
+ * Ideally we'd like not to see any dirty inodes on the
+ * default_backing_dev_info. Until these are tracked down,
+ * perform the same writeback here that bdi_writeback_task
+ * does. For logic, see comment in
+ * fs/fs-writeback.c:bdi_writeback_task()
+ */
+ if (wb_has_dirty_io(me))
+ wb_do_writeback(me);
+
+ /*
+ * This is our real job - check for pending entries in
+ * bdi_pending_list, and create the tasks that got added
+ */
repeat:
bdi = NULL;
spin_lock_bh(&bdi_lock);
@@ -544,12 +551,12 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
ret = -ENOMEM;
goto exit;
}
- } else {
- spin_lock_bh(&bdi_lock);
- list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
- spin_unlock_bh(&bdi_lock);
}
+ spin_lock_bh(&bdi_lock);
+ list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
+ spin_unlock_bh(&bdi_lock);
+
bdi->dev = dev;
bdi_debug_register(bdi, dev_name(dev));
--
1.6.2.2.446.gfbdc0
--
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