X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=fs%2Ffs-writeback.c;h=4c33705489825a8205e3e372415f4aa50ef41147;hb=fe69d560b5bd9ec77b5d5749bd7027344daef47e;hp=8c7e9e51a3980e2915e74997cc34e5044b0eb3a5;hpb=cc396d27d8d5884bbb555efd7783b9e9e2b41dc2;p=linux-2.6-microblaze.git

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 8c7e9e51a398..4c3370548982 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -521,6 +521,9 @@ static bool inode_prepare_wbs_switch(struct inode *inode,
 	 */
 	smp_mb();
 
+	if (IS_DAX(inode))
+		return false;
+
 	/* while holding I_WB_SWITCH, no one else can update the association */
 	spin_lock(&inode->i_lock);
 	if (!(inode->i_sb->s_flags & SB_ACTIVE) ||
@@ -567,9 +570,14 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
 	/* find and pin the new wb */
 	rcu_read_lock();
 	memcg_css = css_from_id(new_wb_id, &memory_cgrp_subsys);
-	if (memcg_css)
-		isw->new_wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+	if (memcg_css && !css_tryget(memcg_css))
+		memcg_css = NULL;
 	rcu_read_unlock();
+	if (!memcg_css)
+		goto out_free;
+
+	isw->new_wb = wb_get_create(bdi, memcg_css, GFP_ATOMIC);
+	css_put(memcg_css);
 	if (!isw->new_wb)
 		goto out_free;