The only place that really needs to be adjusted is commit_tree() -
there we need to iterate through the copy and we might as well
use next_mnt() for that. However, in case when our tree has been
slid under something already mounted (propagation to a mountpoint
that already has something mounted on it or a 'beneath' move_mount)
we need to take care not to walk into the overmounting tree.
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/mount.h | 3 +--
fs/namespace.c | 60 ++++++++++++++++++++------------------------------
fs/pnode.c | 3 ++-
3 files changed, 27 insertions(+), 39 deletions(-)
diff --git a/fs/mount.h b/fs/mount.h
index 4355c482a841..c5b170b6cb3c 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -176,7 +176,7 @@ static inline bool mnt_ns_empty(const struct mnt_namespace *ns)
return RB_EMPTY_ROOT(&ns->mounts);
}
-static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list)
+static inline void move_from_ns(struct mount *mnt)
{
struct mnt_namespace *ns = mnt->mnt_ns;
WARN_ON(!mnt_ns_attached(mnt));
@@ -186,7 +186,6 @@ static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list)
ns->mnt_first_node = rb_next(&mnt->mnt_node);
rb_erase(&mnt->mnt_node, &ns->mounts);
RB_CLEAR_NODE(&mnt->mnt_node);
- list_add_tail(&mnt->mnt_list, dt_list);
}
bool has_locked_children(struct mount *mnt, struct dentry *dentry);
diff --git a/fs/namespace.c b/fs/namespace.c
index 4b123e2384ca..5556c5edbae9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1161,34 +1161,6 @@ static void mnt_add_to_ns(struct mnt_namespace *ns, struct mount *mnt)
mnt_notify_add(mnt);
}
-/*
- * vfsmount lock must be held for write
- */
-static void commit_tree(struct mount *mnt)
-{
- struct mount *parent = mnt->mnt_parent;
- struct mount *m;
- LIST_HEAD(head);
- struct mnt_namespace *n = parent->mnt_ns;
-
- BUG_ON(parent == mnt);
-
- if (!mnt_ns_attached(mnt)) {
- list_add_tail(&head, &mnt->mnt_list);
- while (!list_empty(&head)) {
- m = list_first_entry(&head, typeof(*m), mnt_list);
- list_del(&m->mnt_list);
-
- mnt_add_to_ns(n, m);
- }
- n->nr_mounts += n->pending_mounts;
- n->pending_mounts = 0;
- }
-
- make_visible(mnt);
- touch_mnt_namespace(n);
-}
-
static struct mount *next_mnt(struct mount *p, struct mount *root)
{
struct list_head *next = p->mnt_mounts.next;
@@ -1215,6 +1187,27 @@ static struct mount *skip_mnt_tree(struct mount *p)
return p;
}
+/*
+ * vfsmount lock must be held for write
+ */
+static void commit_tree(struct mount *mnt)
+{
+ struct mnt_namespace *n = mnt->mnt_parent->mnt_ns;
+
+ if (!mnt_ns_attached(mnt)) {
+ for (struct mount *m = mnt; m; m = next_mnt(m, mnt))
+ if (unlikely(mnt_ns_attached(m)))
+ m = skip_mnt_tree(m);
+ else
+ mnt_add_to_ns(n, m);
+ n->nr_mounts += n->pending_mounts;
+ n->pending_mounts = 0;
+ }
+
+ make_visible(mnt);
+ touch_mnt_namespace(n);
+}
+
/**
* vfs_create_mount - Create a mount for a configured superblock
* @fc: The configuration context with the superblock attached
@@ -1831,9 +1824,8 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
for (p = mnt; p; p = next_mnt(p, mnt)) {
p->mnt.mnt_flags |= MNT_UMOUNT;
if (mnt_ns_attached(p))
- move_from_ns(p, &tmp_list);
- else
- list_move(&p->mnt_list, &tmp_list);
+ move_from_ns(p);
+ list_add_tail(&p->mnt_list, &tmp_list);
}
/* Hide the mounts from mnt_mounts */
@@ -2270,7 +2262,6 @@ struct mount *copy_tree(struct mount *src_root, struct dentry *dentry,
list_add(&dst_mnt->mnt_expire,
&src_mnt->mnt_expire);
}
- list_add_tail(&dst_mnt->mnt_list, &res->mnt_list);
attach_mnt(dst_mnt, dst_parent, src_parent->mnt_mp);
unlock_mount_hash();
}
@@ -2686,12 +2677,9 @@ static int attach_recursive_mnt(struct mount *source_mnt,
list_del_init(&source_mnt->mnt_expire);
} else {
if (source_mnt->mnt_ns) {
- LIST_HEAD(head);
-
/* move from anon - the caller will destroy */
for (p = source_mnt; p; p = next_mnt(p, source_mnt))
- move_from_ns(p, &head);
- list_del_init(&head);
+ move_from_ns(p);
}
}
diff --git a/fs/pnode.c b/fs/pnode.c
index 73a64c55deb3..f897a501bee7 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -459,7 +459,8 @@ static void umount_one(struct mount *m, struct list_head *to_umount)
{
m->mnt.mnt_flags |= MNT_UMOUNT;
list_del_init(&m->mnt_child);
- move_from_ns(m, to_umount);
+ move_from_ns(m);
+ list_add_tail(&m->mnt_list, to_umount);
}
static void remove_from_candidate_list(struct mount *m)
--
2.39.5
