From 6b1353cb2664c93997561fa4f46f055da51f5ee7 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 24 Dec 2014 07:20:01 -0600 Subject: [PATCH] mnt: Improve the umount_tree flags [ Upstream commit e819f152104c9f7c9fe50e1aecce6f5d4bf06d65 ] - 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" Signed-off-by: Sasha Levin --- fs/namespace.c | 31 ++++++++++++++++--------------- fs/pnode.h | 1 - 2 files changed, 16 insertions(+), 16 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index bbde147..7ea7e51 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1322,14 +1322,15 @@ static inline void namespace_lock(void) down_write(&namespace_sem); } +enum umount_tree_flags { + UMOUNT_SYNC = 1, + UMOUNT_PROPAGATE = 2, +}; /* * mount_lock must be held * 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); struct mount *p; @@ -1343,7 +1344,7 @@ void umount_tree(struct mount *mnt, int how) hlist_for_each_entry(p, &tmp_list, mnt_hash) list_del_init(&p->mnt_child); - if (how) + if (how & UMOUNT_PROPAGATE) propagate_umount(&tmp_list); hlist_for_each_entry(p, &tmp_list, mnt_hash) { @@ -1351,7 +1352,7 @@ void umount_tree(struct mount *mnt, int how) list_del_init(&p->mnt_list); __touch_mnt_namespace(p->mnt_ns); p->mnt_ns = NULL; - if (how < 2) + if (how & UMOUNT_SYNC) p->mnt.mnt_flags |= MNT_SYNC_UMOUNT; if (mnt_has_parent(p)) { hlist_del_init(&p->mnt_mp_list); @@ -1456,14 +1457,14 @@ static int do_umount(struct mount *mnt, int flags) if (flags & MNT_DETACH) { if (!list_empty(&mnt->mnt_list)) - umount_tree(mnt, 2); + umount_tree(mnt, UMOUNT_PROPAGATE); retval = 0; } else { shrink_submounts(mnt); retval = -EBUSY; if (!propagate_mount_busy(mnt, 2)) { if (!list_empty(&mnt->mnt_list)) - umount_tree(mnt, 1); + umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC); retval = 0; } } @@ -1495,7 +1496,7 @@ void __detach_mounts(struct dentry *dentry) lock_mount_hash(); while (!hlist_empty(&mp->m_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(); put_mountpoint(mp); @@ -1662,7 +1663,7 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry, out: if (res) { lock_mount_hash(); - umount_tree(res, 0); + umount_tree(res, UMOUNT_SYNC); unlock_mount_hash(); } return q; @@ -1686,7 +1687,7 @@ void drop_collected_mounts(struct vfsmount *mnt) { namespace_lock(); lock_mount_hash(); - umount_tree(real_mount(mnt), 0); + umount_tree(real_mount(mnt), UMOUNT_SYNC); unlock_mount_hash(); namespace_unlock(); } @@ -1869,7 +1870,7 @@ static int attach_recursive_mnt(struct mount *source_mnt, out_cleanup_ids: while (!hlist_empty(&tree_list)) { child = hlist_entry(tree_list.first, struct mount, mnt_hash); - umount_tree(child, 0); + umount_tree(child, UMOUNT_SYNC); } unlock_mount_hash(); cleanup_group_ids(source_mnt, NULL); @@ -2046,7 +2047,7 @@ static int do_loopback(struct path *path, const char *old_name, err = graft_tree(mnt, parent, mp); if (err) { lock_mount_hash(); - umount_tree(mnt, 0); + umount_tree(mnt, UMOUNT_SYNC); unlock_mount_hash(); } out2: @@ -2417,7 +2418,7 @@ void mark_mounts_for_expiry(struct list_head *mounts) while (!list_empty(&graveyard)) { mnt = list_first_entry(&graveyard, struct mount, mnt_expire); touch_mnt_namespace(mnt->mnt_ns); - umount_tree(mnt, 1); + umount_tree(mnt, UMOUNT_PROPAGATE|UMOUNT_SYNC); } unlock_mount_hash(); namespace_unlock(); @@ -2488,7 +2489,7 @@ static void shrink_submounts(struct mount *mnt) m = list_first_entry(&graveyard, struct mount, mnt_expire); touch_mnt_namespace(m->mnt_ns); - umount_tree(m, 1); + umount_tree(m, UMOUNT_PROPAGATE|UMOUNT_SYNC); } } } diff --git a/fs/pnode.h b/fs/pnode.h index 4a24635..16afc3d 100644 --- a/fs/pnode.h +++ b/fs/pnode.h @@ -47,7 +47,6 @@ int get_dominating_id(struct mount *mnt, const struct path *root); unsigned int mnt_get_count(struct mount *mnt); void mnt_set_mountpoint(struct mount *, struct mountpoint *, struct mount *); -void umount_tree(struct mount *, int); struct mount *copy_tree(struct mount *, struct dentry *, int); bool is_path_reachable(struct mount *, struct dentry *, const struct path *root); -- 2.7.4