Sample the current rcu state and kick off a new grace period after we're
done with umount_tree() and make namespace_unlock() take the previous
state into account before invoking synchronize_rcu_expedited().
Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
---
fs/namespace.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index d9ca80dcc544..287189e85af5 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -77,6 +77,7 @@ static struct hlist_head *mount_hashtable __ro_after_init;
static struct hlist_head *mountpoint_hashtable __ro_after_init;
static struct kmem_cache *mnt_cache __ro_after_init;
static DECLARE_RWSEM(namespace_sem);
+static struct rcu_gp_oldstate rcu_unmount_gp;
static HLIST_HEAD(unmounted); /* protected by namespace_sem */
static LIST_HEAD(ex_mountpoints); /* protected by namespace_sem */
static DEFINE_SEQLOCK(mnt_ns_tree_lock);
@@ -1817,7 +1818,7 @@ static void namespace_unlock(void)
if (likely(hlist_empty(&head)))
return;
- synchronize_rcu_expedited();
+ cond_synchronize_rcu_expedited_full(&rcu_unmount_gp);
hlist_for_each_entry_safe(m, p, &head, mnt_umount) {
hlist_del(&m->mnt_umount);
@@ -1939,6 +1940,9 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
*/
mnt_notify_add(p);
}
+
+ /* Record current grace period state and kick of new grace period. */
+ start_poll_synchronize_rcu_expedited_full(&rcu_unmount_gp);
}
static void shrink_submounts(struct mount *mnt);
--
2.47.2
--wlvjtn7bxagetzkl--
