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-rw-r--r--fs/namespace.c31
1 files changed, 24 insertions, 7 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 48809e21f270..9f544f35ed34 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -611,6 +611,21 @@ static void attach_mnt(struct vfsmount *mnt, struct path *path)
list_add_tail(&mnt->mnt_child, &path->mnt->mnt_mounts);
}
+static inline void __mnt_make_longterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_inc(&mnt->mnt_longterm);
+#endif
+}
+
+/* needs vfsmount lock for write */
+static inline void __mnt_make_shortterm(struct vfsmount *mnt)
+{
+#ifdef CONFIG_SMP
+ atomic_dec(&mnt->mnt_longterm);
+#endif
+}
+
/*
* vfsmount lock must be held for write
*/
@@ -626,7 +641,7 @@ static void commit_tree(struct vfsmount *mnt)
list_add_tail(&head, &mnt->mnt_list);
list_for_each_entry(m, &head, mnt_list) {
m->mnt_ns = n;
- atomic_inc(&m->mnt_longterm);
+ __mnt_make_longterm(m);
}
list_splice(&head, n->list.prev);
@@ -1189,7 +1204,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill)
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL;
- atomic_dec(&p->mnt_longterm);
+ __mnt_make_shortterm(p);
list_del_init(&p->mnt_child);
if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;
@@ -2243,16 +2258,18 @@ static struct mnt_namespace *alloc_mnt_ns(void)
void mnt_make_longterm(struct vfsmount *mnt)
{
- atomic_inc(&mnt->mnt_longterm);
+ __mnt_make_longterm(mnt);
}
void mnt_make_shortterm(struct vfsmount *mnt)
{
+#ifdef CONFIG_SMP
if (atomic_add_unless(&mnt->mnt_longterm, -1, 1))
return;
br_write_lock(vfsmount_lock);
atomic_dec(&mnt->mnt_longterm);
br_write_unlock(vfsmount_lock);
+#endif
}
/*
@@ -2292,17 +2309,17 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
q = new_ns->root;
while (p) {
q->mnt_ns = new_ns;
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
if (fs) {
if (p == fs->root.mnt) {
fs->root.mnt = mntget(q);
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
mnt_make_shortterm(p);
rootmnt = p;
}
if (p == fs->pwd.mnt) {
fs->pwd.mnt = mntget(q);
- atomic_inc(&q->mnt_longterm);
+ __mnt_make_longterm(q);
mnt_make_shortterm(p);
pwdmnt = p;
}
@@ -2348,7 +2365,7 @@ struct mnt_namespace *create_mnt_ns(struct vfsmount *mnt)
new_ns = alloc_mnt_ns();
if (!IS_ERR(new_ns)) {
mnt->mnt_ns = new_ns;
- atomic_inc(&mnt->mnt_longterm);
+ __mnt_make_longterm(mnt);
new_ns->root = mnt;
list_add(&new_ns->list, &new_ns->root->mnt_list);
}