switch the IO-triggering parts of umount to fs_pin
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/namespace.c b/fs/namespace.c
index cd1e968..4a985ff 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -190,6 +190,14 @@
#endif
}
+static void drop_mountpoint(struct fs_pin *p)
+{
+ struct mount *m = container_of(p, struct mount, mnt_umount);
+ dput(m->mnt_ex_mountpoint);
+ pin_remove(p);
+ mntput(&m->mnt);
+}
+
static struct mount *alloc_vfsmnt(const char *name)
{
struct mount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
@@ -229,6 +237,7 @@
#ifdef CONFIG_FSNOTIFY
INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks);
#endif
+ init_fs_pin(&mnt->mnt_umount, drop_mountpoint);
}
return mnt;
@@ -1289,7 +1298,6 @@
static void namespace_unlock(void)
{
- struct mount *mnt;
struct hlist_head head = unmounted;
if (likely(hlist_empty(&head))) {
@@ -1299,23 +1307,11 @@
head.first->pprev = &head.first;
INIT_HLIST_HEAD(&unmounted);
-
- /* undo decrements we'd done in umount_tree() */
- hlist_for_each_entry(mnt, &head, mnt_hash)
- if (mnt->mnt_ex_mountpoint.mnt)
- mntget(mnt->mnt_ex_mountpoint.mnt);
-
up_write(&namespace_sem);
synchronize_rcu();
- while (!hlist_empty(&head)) {
- mnt = hlist_entry(head.first, struct mount, mnt_hash);
- hlist_del_init(&mnt->mnt_hash);
- if (mnt->mnt_ex_mountpoint.mnt)
- path_put(&mnt->mnt_ex_mountpoint);
- mntput(&mnt->mnt);
- }
+ group_pin_kill(&head);
}
static inline void namespace_lock(void)
@@ -1334,7 +1330,6 @@
{
HLIST_HEAD(tmp_list);
struct mount *p;
- struct mount *last = NULL;
for (p = mnt; p; p = next_mnt(p, mnt)) {
hlist_del_init_rcu(&p->mnt_hash);
@@ -1347,33 +1342,28 @@
if (how)
propagate_umount(&tmp_list);
- hlist_for_each_entry(p, &tmp_list, mnt_hash) {
+ while (!hlist_empty(&tmp_list)) {
+ p = hlist_entry(tmp_list.first, struct mount, mnt_hash);
+ hlist_del_init_rcu(&p->mnt_hash);
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
if (how < 2)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
+
+ pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted);
if (mnt_has_parent(p)) {
hlist_del_init(&p->mnt_mp_list);
put_mountpoint(p->mnt_mp);
mnt_add_count(p->mnt_parent, -1);
- /* move the reference to mountpoint into ->mnt_ex_mountpoint */
- p->mnt_ex_mountpoint.dentry = p->mnt_mountpoint;
- p->mnt_ex_mountpoint.mnt = &p->mnt_parent->mnt;
+ /* old mountpoint will be dropped when we can do that */
+ p->mnt_ex_mountpoint = p->mnt_mountpoint;
p->mnt_mountpoint = p->mnt.mnt_root;
p->mnt_parent = p;
p->mnt_mp = NULL;
}
change_mnt_propagation(p, MS_PRIVATE);
- last = p;
- }
- if (last) {
- last->mnt_hash.next = unmounted.first;
- if (unmounted.first)
- unmounted.first->pprev = &last->mnt_hash.next;
- unmounted.first = tmp_list.first;
- unmounted.first->pprev = &unmounted.first;
}
}