4.0-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
commit c003b26ff98ca04a180ff34c38c007a3998d62f9 upstream.
umount_tree builds a list of mounts that need to be unmounted.
Utilize mnt_list for this purpose instead of mnt_hash. This begins to
allow keeping a mount on the mnt_hash after it is unmounted, which is
necessary for a properly functioning MNT_LOCKED implementation.
The fact that mnt_list is an ordinary list makding available list_move
is nice bonus.
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 20 +++++++++++---------
fs/pnode.c | 6 +++---
fs/pnode.h | 2 +-
3 files changed, 15 insertions(+), 13 deletions(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1329,23 +1329,25 @@ enum umount_tree_flags {
*/
static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
{
- HLIST_HEAD(tmp_list);
+ LIST_HEAD(tmp_list);
struct mount *p;
- for (p = mnt; p; p = next_mnt(p, mnt)) {
- hlist_del_init_rcu(&p->mnt_hash);
- hlist_add_head(&p->mnt_hash, &tmp_list);
- }
+ /* Gather the mounts to umount */
+ for (p = mnt; p; p = next_mnt(p, mnt))
+ list_move(&p->mnt_list, &tmp_list);
- hlist_for_each_entry(p, &tmp_list, mnt_hash)
+ /* Hide the mounts from lookup_mnt and mnt_mounts */
+ list_for_each_entry(p, &tmp_list, mnt_list) {
+ hlist_del_init_rcu(&p->mnt_hash);
list_del_init(&p->mnt_child);
+ }
+ /* Add propogated mounts to the tmp_list */
if (how & UMOUNT_PROPAGATE)
propagate_umount(&tmp_list);
- while (!hlist_empty(&tmp_list)) {
- p = hlist_entry(tmp_list.first, struct mount, mnt_hash);
- hlist_del_init_rcu(&p->mnt_hash);
+ while (!list_empty(&tmp_list)) {
+ p = list_first_entry(&tmp_list, struct mount, mnt_list);
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -384,7 +384,7 @@ static void __propagate_umount(struct mo
if (child && list_empty(&child->mnt_mounts)) {
list_del_init(&child->mnt_child);
hlist_del_init_rcu(&child->mnt_hash);
- hlist_add_before_rcu(&child->mnt_hash, &mnt->mnt_hash);
+ list_move_tail(&child->mnt_list, &mnt->mnt_list);
}
}
}
@@ -396,11 +396,11 @@ static void __propagate_umount(struct mo
*
* vfsmount lock must be held for write
*/
-int propagate_umount(struct hlist_head *list)
+int propagate_umount(struct list_head *list)
{
struct mount *mnt;
- hlist_for_each_entry(mnt, list, mnt_hash)
+ list_for_each_entry(mnt, list, mnt_list)
__propagate_umount(mnt);
return 0;
}
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -40,7 +40,7 @@ static inline void set_mnt_shared(struct
void change_mnt_propagation(struct mount *, int);
int propagate_mnt(struct mount *, struct mountpoint *, struct mount *,
struct hlist_head *);
-int propagate_umount(struct hlist_head *);
+int propagate_umount(struct list_head *);
int propagate_mount_busy(struct mount *, int);
void mnt_release_group_id(struct mount *);
int get_dominating_id(struct mount *mnt, const struct path *root);
--
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