From 1d6a32acd70ab18499829c0a9a5dbe2bace72a13 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 20 Mar 2014 20:34:43 -0400 Subject: [PATCH] keep shadowed vfsmounts together preparation to switching mnt_hash to hlist Cc: stable@vger.kernel.org Signed-off-by: Al Viro --- fs/namespace.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 3b648da55d87..9db3ce397a83 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -621,12 +621,20 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry) { struct list_head *head = m_hash(mnt, dentry); - struct mount *p; + struct mount *p, *res = NULL; - list_for_each_entry_reverse(p, head, mnt_hash) + list_for_each_entry(p, head, mnt_hash) if (&p->mnt_parent->mnt == mnt && p->mnt_mountpoint == dentry) - return p; - return NULL; + goto found; + return res; +found: + res = p; + list_for_each_entry_continue(p, head, mnt_hash) { + if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry) + break; + res = p; + } + return res; } /* @@ -769,14 +777,14 @@ static void attach_mnt(struct mount *mnt, struct mountpoint *mp) { mnt_set_mountpoint(parent, mp, mnt); - list_add_tail(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry)); + list_add(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry)); list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); } /* * vfsmount lock must be held for write */ -static void commit_tree(struct mount *mnt) +static void commit_tree(struct mount *mnt, struct mount *shadows) { struct mount *parent = mnt->mnt_parent; struct mount *m; @@ -791,7 +799,10 @@ static void commit_tree(struct mount *mnt) list_splice(&head, n->list.prev); - list_add_tail(&mnt->mnt_hash, + if (shadows) + list_add(&mnt->mnt_hash, &shadows->mnt_hash); + else + list_add(&mnt->mnt_hash, m_hash(&parent->mnt, mnt->mnt_mountpoint)); list_add_tail(&mnt->mnt_child, &parent->mnt_mounts); touch_mnt_namespace(n); @@ -1659,12 +1670,15 @@ static int attach_recursive_mnt(struct mount *source_mnt, touch_mnt_namespace(source_mnt->mnt_ns); } else { mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt); - commit_tree(source_mnt); + commit_tree(source_mnt, NULL); } list_for_each_entry_safe(child, p, &tree_list, mnt_hash) { + struct mount *q; list_del_init(&child->mnt_hash); - commit_tree(child); + q = __lookup_mnt_last(&child->mnt_parent->mnt, + child->mnt_mountpoint); + commit_tree(child, q); } unlock_mount_hash(); -- 2.34.1