summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--fs/pnode.c32
-rw-r--r--fs/pnode.h1
2 files changed, 30 insertions, 3 deletions
diff --git a/fs/pnode.c b/fs/pnode.c
index 89890293dd0a..6367e1e435c6 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -382,6 +382,26 @@ void propagate_mount_unlock(struct mount *mnt)
}
/*
+ * Mark all mounts that the MNT_LOCKED logic will allow to be unmounted.
+ */
+static void mark_umount_candidates(struct mount *mnt)
+{
+ struct mount *parent = mnt->mnt_parent;
+ struct mount *m;
+
+ BUG_ON(parent == mnt);
+
+ for (m = propagation_next(parent, parent); m;
+ m = propagation_next(m, parent)) {
+ struct mount *child = __lookup_mnt_last(&m->mnt,
+ mnt->mnt_mountpoint);
+ if (child && (!IS_MNT_LOCKED(child) || IS_MNT_MARKED(m))) {
+ SET_MNT_MARK(child);
+ }
+ }
+}
+
+/*
* NOTE: unmounting 'mnt' naturally propagates to all other mounts its
* parent propagates to.
*/
@@ -398,10 +418,13 @@ static void __propagate_umount(struct mount *mnt)
struct mount *child = __lookup_mnt_last(&m->mnt,
mnt->mnt_mountpoint);
/*
- * umount the child only if the child has no
- * other children
+ * umount the child only if the child has no children
+ * and the child is marked safe to unmount.
*/
- if (child && list_empty(&child->mnt_mounts)) {
+ if (!child || !IS_MNT_MARKED(child))
+ continue;
+ CLEAR_MNT_MARK(child);
+ if (list_empty(&child->mnt_mounts)) {
list_del_init(&child->mnt_child);
child->mnt.mnt_flags |= MNT_UMOUNT;
list_move_tail(&child->mnt_list, &mnt->mnt_list);
@@ -420,6 +443,9 @@ int propagate_umount(struct list_head *list)
{
struct mount *mnt;
+ list_for_each_entry_reverse(mnt, list, mnt_list)
+ mark_umount_candidates(mnt);
+
list_for_each_entry(mnt, list, mnt_list)
__propagate_umount(mnt);
return 0;
diff --git a/fs/pnode.h b/fs/pnode.h
index af47d4bd7b31..0fcdbe7ca648 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -19,6 +19,7 @@
#define IS_MNT_MARKED(m) ((m)->mnt.mnt_flags & MNT_MARKED)
#define SET_MNT_MARK(m) ((m)->mnt.mnt_flags |= MNT_MARKED)
#define CLEAR_MNT_MARK(m) ((m)->mnt.mnt_flags &= ~MNT_MARKED)
+#define IS_MNT_LOCKED(m) ((m)->mnt.mnt_flags & MNT_LOCKED)
#define CL_EXPIRE 0x01
#define CL_SLAVE 0x02