reorganize do_make_slave()
Make sure that clone_mnt() never returns a mount with MNT_SHARED in flags, but without a valid ->mnt_group_id. That allows to demystify do_make_slave() quite a bit, among other things. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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parent
066715d3fd
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5235d448c4
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@ -1030,6 +1030,8 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
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if (IS_MNT_SLAVE(old))
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list_add(&mnt->mnt_slave, &old->mnt_slave);
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mnt->mnt_master = old->mnt_master;
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} else {
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CLEAR_MNT_SHARED(mnt);
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}
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if (flag & CL_MAKE_SHARED)
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set_mnt_shared(mnt);
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62
fs/pnode.c
62
fs/pnode.c
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@ -67,39 +67,15 @@ int get_dominating_id(struct mount *mnt, const struct path *root)
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static int do_make_slave(struct mount *mnt)
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{
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struct mount *peer_mnt = mnt, *master = mnt->mnt_master;
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struct mount *slave_mnt;
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struct mount *master, *slave_mnt;
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/*
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* slave 'mnt' to a peer mount that has the
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* same root dentry. If none is available then
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* slave it to anything that is available.
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*/
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while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
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peer_mnt->mnt.mnt_root != mnt->mnt.mnt_root) ;
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if (peer_mnt == mnt) {
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peer_mnt = next_peer(mnt);
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if (peer_mnt == mnt)
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peer_mnt = NULL;
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}
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if (mnt->mnt_group_id && IS_MNT_SHARED(mnt) &&
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list_empty(&mnt->mnt_share))
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if (list_empty(&mnt->mnt_share)) {
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if (IS_MNT_SHARED(mnt)) {
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mnt_release_group_id(mnt);
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list_del_init(&mnt->mnt_share);
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mnt->mnt_group_id = 0;
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if (peer_mnt)
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master = peer_mnt;
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if (master) {
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list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
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slave_mnt->mnt_master = master;
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list_move(&mnt->mnt_slave, &master->mnt_slave_list);
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list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
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INIT_LIST_HEAD(&mnt->mnt_slave_list);
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} else {
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CLEAR_MNT_SHARED(mnt);
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}
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master = mnt->mnt_master;
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if (!master) {
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struct list_head *p = &mnt->mnt_slave_list;
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while (!list_empty(p)) {
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slave_mnt = list_first_entry(p,
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@ -107,9 +83,31 @@ static int do_make_slave(struct mount *mnt)
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list_del_init(&slave_mnt->mnt_slave);
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slave_mnt->mnt_master = NULL;
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}
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return 0;
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}
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mnt->mnt_master = master;
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} else {
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struct mount *m;
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/*
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* slave 'mnt' to a peer mount that has the
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* same root dentry. If none is available then
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* slave it to anything that is available.
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*/
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for (m = master = next_peer(mnt); m != mnt; m = next_peer(m)) {
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if (m->mnt.mnt_root == mnt->mnt.mnt_root) {
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master = m;
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break;
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}
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}
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list_del_init(&mnt->mnt_share);
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mnt->mnt_group_id = 0;
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CLEAR_MNT_SHARED(mnt);
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}
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list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
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slave_mnt->mnt_master = master;
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list_move(&mnt->mnt_slave, &master->mnt_slave_list);
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list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
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INIT_LIST_HEAD(&mnt->mnt_slave_list);
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mnt->mnt_master = master;
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return 0;
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}
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