[PATCH 4.2.y-ckt 265/273] writeback: initialize inode members that track writeback history

[Kamal Mostafa]

4.2.8-ckt5 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Tahsin Erdogan <tahsin at google.com>

commit 3d65ae4634ed8350aee98a4e6f4e41fe40c7d282 upstream.

inode struct members that track cgroup writeback information
should be reinitialized when inode gets allocated from
kmem_cache. Otherwise, their values remain and get used by the
new inode.

Signed-off-by: Tahsin Erdogan <tahsin at google.com>
Acked-by: Tejun Heo <tj at kernel.org>
Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching")
Signed-off-by: Jens Axboe <axboe at fb.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/inode.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index d30640f..8d72fac 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -156,6 +156,12 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_rdev = 0;
 	inode->dirtied_when = 0;
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+	inode->i_wb_frn_winner = 0;
+	inode->i_wb_frn_avg_time = 0;
+	inode->i_wb_frn_history = 0;
+#endif
+
 	if (security_inode_alloc(inode))
 		goto out;
 	spin_lock_init(&inode->i_lock);
-- 
2.7.0