mnt: Improve the umount_tree flags
- Remove the unneeded declaration from pnode.h - Mark umount_tree static as it has no callers outside of namespace.c - Define an enumeration of umount_tree's flags. - Pass umount_tree's flags in by name This removes the magic numbers 0, 1 and 2 making the code a little clearer and makes it possible for there to be lazy unmounts that don't propagate. Which is what __detach_mounts actually wants for example. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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a3b3c5627c
Коммит
e819f15210
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@ -1317,14 +1317,15 @@ static inline void namespace_lock(void)
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down_write(&namespace_sem);
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}
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enum umount_tree_flags {
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UMOUNT_SYNC = 1,
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UMOUNT_PROPAGATE = 2,
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};
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/*
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* mount_lock must be held
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* namespace_sem must be held for write
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* how = 0 => just this tree, don't propagate
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* how = 1 => propagate; we know that nobody else has reference to any victims
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* how = 2 => lazy umount
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*/
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void umount_tree(struct mount *mnt, int how)
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static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
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{
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HLIST_HEAD(tmp_list);
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struct mount *p;
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@ -1337,7 +1338,7 @@ void umount_tree(struct mount *mnt, int how)
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hlist_for_each_entry(p, &tmp_list, mnt_hash)
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list_del_init(&p->mnt_child);
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if (how)
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if (how & UMOUNT_PROPAGATE)
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propagate_umount(&tmp_list);
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while (!hlist_empty(&tmp_list)) {
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@ -1347,7 +1348,7 @@ void umount_tree(struct mount *mnt, int how)
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list_del_init(&p->mnt_list);
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__touch_mnt_namespace(p->mnt_ns);
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p->mnt_ns = NULL;
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if (how < 2)
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if (how & UMOUNT_SYNC)
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p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
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pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted);
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@ -1445,14 +1446,14 @@ static int do_umount(struct mount *mnt, int flags)
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if (flags & MNT_DETACH) {
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if (!list_empty(&mnt->mnt_list))
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umount_tree(mnt, 2);
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umount_tree(mnt, UMOUNT_PROPAGATE);
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retval = 0;
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} else {
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shrink_submounts(mnt);
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retval = -EBUSY;
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if (!propagate_mount_busy(mnt, 2)) {
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if (!list_empty(&mnt->mnt_list))
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umount_tree(mnt, 1);
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umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
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retval = 0;
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}
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}
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@ -1484,7 +1485,7 @@ void __detach_mounts(struct dentry *dentry)
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lock_mount_hash();
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while (!hlist_empty(&mp->m_list)) {
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mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
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umount_tree(mnt, 2);
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umount_tree(mnt, UMOUNT_PROPAGATE);
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}
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unlock_mount_hash();
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put_mountpoint(mp);
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@ -1646,7 +1647,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
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out:
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if (res) {
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lock_mount_hash();
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umount_tree(res, 0);
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umount_tree(res, UMOUNT_SYNC);
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unlock_mount_hash();
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}
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return q;
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@ -1670,7 +1671,7 @@ void drop_collected_mounts(struct vfsmount *mnt)
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{
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namespace_lock();
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lock_mount_hash();
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umount_tree(real_mount(mnt), 0);
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umount_tree(real_mount(mnt), UMOUNT_SYNC);
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unlock_mount_hash();
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namespace_unlock();
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}
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@ -1853,7 +1854,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
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out_cleanup_ids:
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while (!hlist_empty(&tree_list)) {
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child = hlist_entry(tree_list.first, struct mount, mnt_hash);
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umount_tree(child, 0);
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umount_tree(child, UMOUNT_SYNC);
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}
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unlock_mount_hash();
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cleanup_group_ids(source_mnt, NULL);
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@ -2033,7 +2034,7 @@ static int do_loopback(struct path *path, const char *old_name,
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err = graft_tree(mnt, parent, mp);
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if (err) {
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lock_mount_hash();
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umount_tree(mnt, 0);
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umount_tree(mnt, UMOUNT_SYNC);
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unlock_mount_hash();
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}
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out2:
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@ -2404,7 +2405,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
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while (!list_empty(&graveyard)) {
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mnt = list_first_entry(&graveyard, struct mount, mnt_expire);
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touch_mnt_namespace(mnt->mnt_ns);
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umount_tree(mnt, 1);
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umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
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}
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unlock_mount_hash();
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namespace_unlock();
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@ -2475,7 +2476,7 @@ static void shrink_submounts(struct mount *mnt)
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m = list_first_entry(&graveyard, struct mount,
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mnt_expire);
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touch_mnt_namespace(m->mnt_ns);
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umount_tree(m, 1);
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umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC);
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}
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}
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}
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@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt, const struct path *root);
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unsigned int mnt_get_count(struct mount *mnt);
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void mnt_set_mountpoint(struct mount *, struct mountpoint *,
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struct mount *);
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void umount_tree(struct mount *, int);
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struct mount *copy_tree(struct mount *, struct dentry *, int);
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bool is_path_reachable(struct mount *, struct dentry *,
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const struct path *root);
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