Commit e819f152 authored by Eric W. Biederman's avatar Eric W. Biederman

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: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent a3b3c562
...@@ -1317,14 +1317,15 @@ static inline void namespace_lock(void) ...@@ -1317,14 +1317,15 @@ static inline void namespace_lock(void)
down_write(&namespace_sem); down_write(&namespace_sem);
} }
enum umount_tree_flags {
UMOUNT_SYNC = 1,
UMOUNT_PROPAGATE = 2,
};
/* /*
* mount_lock must be held * mount_lock must be held
* namespace_sem must be held for write * namespace_sem must be held for write
* how = 0 => just this tree, don't propagate
* how = 1 => propagate; we know that nobody else has reference to any victims
* how = 2 => lazy umount
*/ */
void umount_tree(struct mount *mnt, int how) static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
{ {
HLIST_HEAD(tmp_list); HLIST_HEAD(tmp_list);
struct mount *p; struct mount *p;
...@@ -1337,7 +1338,7 @@ void umount_tree(struct mount *mnt, int how) ...@@ -1337,7 +1338,7 @@ void umount_tree(struct mount *mnt, int how)
hlist_for_each_entry(p, &tmp_list, mnt_hash) hlist_for_each_entry(p, &tmp_list, mnt_hash)
list_del_init(&p->mnt_child); list_del_init(&p->mnt_child);
if (how) if (how & UMOUNT_PROPAGATE)
propagate_umount(&tmp_list); propagate_umount(&tmp_list);
while (!hlist_empty(&tmp_list)) { while (!hlist_empty(&tmp_list)) {
...@@ -1347,7 +1348,7 @@ void umount_tree(struct mount *mnt, int how) ...@@ -1347,7 +1348,7 @@ void umount_tree(struct mount *mnt, int how)
list_del_init(&p->mnt_list); list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns); __touch_mnt_namespace(p->mnt_ns);
p->mnt_ns = NULL; p->mnt_ns = NULL;
if (how < 2) if (how & UMOUNT_SYNC)
p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted); pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted);
...@@ -1445,14 +1446,14 @@ static int do_umount(struct mount *mnt, int flags) ...@@ -1445,14 +1446,14 @@ static int do_umount(struct mount *mnt, int flags)
if (flags & MNT_DETACH) { if (flags & MNT_DETACH) {
if (!list_empty(&mnt->mnt_list)) if (!list_empty(&mnt->mnt_list))
umount_tree(mnt, 2); umount_tree(mnt, UMOUNT_PROPAGATE);
retval = 0; retval = 0;
} else { } else {
shrink_submounts(mnt); shrink_submounts(mnt);
retval = -EBUSY; retval = -EBUSY;
if (!propagate_mount_busy(mnt, 2)) { if (!propagate_mount_busy(mnt, 2)) {
if (!list_empty(&mnt->mnt_list)) if (!list_empty(&mnt->mnt_list))
umount_tree(mnt, 1); umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
retval = 0; retval = 0;
} }
} }
...@@ -1484,7 +1485,7 @@ void __detach_mounts(struct dentry *dentry) ...@@ -1484,7 +1485,7 @@ void __detach_mounts(struct dentry *dentry)
lock_mount_hash(); lock_mount_hash();
while (!hlist_empty(&mp->m_list)) { while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
umount_tree(mnt, 2); umount_tree(mnt, UMOUNT_PROPAGATE);
} }
unlock_mount_hash(); unlock_mount_hash();
put_mountpoint(mp); put_mountpoint(mp);
...@@ -1646,7 +1647,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry, ...@@ -1646,7 +1647,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
out: out:
if (res) { if (res) {
lock_mount_hash(); lock_mount_hash();
umount_tree(res, 0); umount_tree(res, UMOUNT_SYNC);
unlock_mount_hash(); unlock_mount_hash();
} }
return q; return q;
...@@ -1670,7 +1671,7 @@ void drop_collected_mounts(struct vfsmount *mnt) ...@@ -1670,7 +1671,7 @@ void drop_collected_mounts(struct vfsmount *mnt)
{ {
namespace_lock(); namespace_lock();
lock_mount_hash(); lock_mount_hash();
umount_tree(real_mount(mnt), 0); umount_tree(real_mount(mnt), UMOUNT_SYNC);
unlock_mount_hash(); unlock_mount_hash();
namespace_unlock(); namespace_unlock();
} }
...@@ -1853,7 +1854,7 @@ static int attach_recursive_mnt(struct mount *source_mnt, ...@@ -1853,7 +1854,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
out_cleanup_ids: out_cleanup_ids:
while (!hlist_empty(&tree_list)) { while (!hlist_empty(&tree_list)) {
child = hlist_entry(tree_list.first, struct mount, mnt_hash); child = hlist_entry(tree_list.first, struct mount, mnt_hash);
umount_tree(child, 0); umount_tree(child, UMOUNT_SYNC);
} }
unlock_mount_hash(); unlock_mount_hash();
cleanup_group_ids(source_mnt, NULL); cleanup_group_ids(source_mnt, NULL);
...@@ -2033,7 +2034,7 @@ static int do_loopback(struct path *path, const char *old_name, ...@@ -2033,7 +2034,7 @@ static int do_loopback(struct path *path, const char *old_name,
err = graft_tree(mnt, parent, mp); err = graft_tree(mnt, parent, mp);
if (err) { if (err) {
lock_mount_hash(); lock_mount_hash();
umount_tree(mnt, 0); umount_tree(mnt, UMOUNT_SYNC);
unlock_mount_hash(); unlock_mount_hash();
} }
out2: out2:
...@@ -2404,7 +2405,7 @@ void mark_mounts_for_expiry(struct list_head *mounts) ...@@ -2404,7 +2405,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
while (!list_empty(&graveyard)) { while (!list_empty(&graveyard)) {
mnt = list_first_entry(&graveyard, struct mount, mnt_expire); mnt = list_first_entry(&graveyard, struct mount, mnt_expire);
touch_mnt_namespace(mnt->mnt_ns); touch_mnt_namespace(mnt->mnt_ns);
umount_tree(mnt, 1); umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC);
} }
unlock_mount_hash(); unlock_mount_hash();
namespace_unlock(); namespace_unlock();
...@@ -2475,7 +2476,7 @@ static void shrink_submounts(struct mount *mnt) ...@@ -2475,7 +2476,7 @@ static void shrink_submounts(struct mount *mnt)
m = list_first_entry(&graveyard, struct mount, m = list_first_entry(&graveyard, struct mount,
mnt_expire); mnt_expire);
touch_mnt_namespace(m->mnt_ns); touch_mnt_namespace(m->mnt_ns);
umount_tree(m, 1); umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC);
} }
} }
} }
......
...@@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt, const struct path *root); ...@@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt, const struct path *root);
unsigned int mnt_get_count(struct mount *mnt); unsigned int mnt_get_count(struct mount *mnt);
void mnt_set_mountpoint(struct mount *, struct mountpoint *, void mnt_set_mountpoint(struct mount *, struct mountpoint *,
struct mount *); struct mount *);
void umount_tree(struct mount *, int);
struct mount *copy_tree(struct mount *, struct dentry *, int); struct mount *copy_tree(struct mount *, struct dentry *, int);
bool is_path_reachable(struct mount *, struct dentry *, bool is_path_reachable(struct mount *, struct dentry *,
const struct path *root); const struct path *root);
......
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