linux-kernel - [ 51/79] bcache: Fix a sysfs splat on shutdown

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Message-Id: <20130726204727.905469344@linuxfoundation.org>
Date:	Fri, 26 Jul 2013 13:47:41 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Kent Overstreet <kmo@...erainc.com>
Subject: [ 51/79] bcache: Fix a sysfs splat on shutdown

3.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kent Overstreet <kmo@...erainc.com>

commit c9502ea4424b31728703d113fc6b30bfead14633 upstream.

If we stopped a bcache device when we were already detaching (or
something like that), bcache_device_unlink() would try to remove a
symlink from sysfs that was already gone because the bcache dev kobject
had already been removed from sysfs.

So keep track of whether we've removed stuff from sysfs.

Signed-off-by: Kent Overstreet <kmo@...erainc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/md/bcache/bcache.h |    1 +
 drivers/md/bcache/super.c  |   11 ++++++++++-
 2 files changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -437,6 +437,7 @@ struct bcache_device {
 
 	/* If nonzero, we're detaching/unregistering from cache set */
 	atomic_t		detaching;
+	int			flush_done;
 
 	atomic_long_t		sectors_dirty;
 	unsigned long		sectors_dirty_gc;
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -704,7 +704,8 @@ static void bcache_device_detach(struct
 		atomic_set(&d->detaching, 0);
 	}
 
-	bcache_device_unlink(d);
+	if (!d->flush_done)
+		bcache_device_unlink(d);
 
 	d->c->devices[d->id] = NULL;
 	closure_put(&d->c->caching);
@@ -1016,6 +1017,14 @@ static void cached_dev_flush(struct clos
 	struct cached_dev *dc = container_of(cl, struct cached_dev, disk.cl);
 	struct bcache_device *d = &dc->disk;
 
+	mutex_lock(&bch_register_lock);
+	d->flush_done = 1;
+
+	if (d->c)
+		bcache_device_unlink(d);
+
+	mutex_unlock(&bch_register_lock);
+
 	bch_cache_accounting_destroy(&dc->accounting);
 	kobject_del(&d->kobj);
 


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