The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.38
------>
commit d986e2a72ad3e92ba95dac9bb4f720cdb5206be1
Author: Konstantin Khorenko <[email protected]>
Date: Wed Jun 9 18:16:01 2021 +0300
mnt_ns: introduce global list of mount namespaces for debug
We've got several cases when ploop could not be unmounted resulting in
-EBUSY. Sometimes we could find what holds it sometimes not, so let's
introduce the global list of mount namespaces: it will make it easier to
debug such cases.
https://jira.sw.ru/browse/PSBM-80869
Signed-off-by: Konstantin Khorenko <[email protected]>
Reviewed-by: Andrey Ryabinin <[email protected]>
(cherry picked from vz7 commit abee9d40a8d1 ("mnt_ns: introduce global list
of
mount namespaces for debug"))
VZ 8 rebase part https://jira.sw.ru/browse/PSBM-127837
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
---
fs/mount.h | 1 +
fs/namespace.c | 14 ++++++++++++++
2 files changed, 15 insertions(+)
diff --git a/fs/mount.h b/fs/mount.h
index e3e0379d5c47..9225fc7bce30 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -17,6 +17,7 @@ struct mnt_namespace {
u64 event;
unsigned int mounts; /* # of mounts in the namespace */
unsigned int pending_mounts;
+ struct list_head mntns_list;
} __randomize_layout;
struct mnt_pcp {
diff --git a/fs/namespace.c b/fs/namespace.c
index adedb5839907..0096fbb71774 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3262,6 +3262,10 @@ static void free_mnt_ns(struct mnt_namespace *ns)
ns_free_inum(&ns->ns);
dec_mnt_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
+
+ namespace_lock();
+ list_del(&ns->mntns_list);
+ namespace_unlock();
kfree(ns);
}
@@ -3273,6 +3277,7 @@ static void free_mnt_ns(struct mnt_namespace *ns)
* is effectively never, so we can ignore the possibility.
*/
static atomic64_t mnt_ns_seq = ATOMIC64_INIT(1);
+static LIST_HEAD(all_mntns_list); /* protected by namespace_sem */
static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns, bool
anon)
{
@@ -3302,6 +3307,7 @@ static struct mnt_namespace *alloc_mnt_ns(struct
user_namespace *user_ns, bool a
new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
atomic_set(&new_ns->count, 1);
INIT_LIST_HEAD(&new_ns->list);
+ INIT_LIST_HEAD(&new_ns->mntns_list);
init_waitqueue_head(&new_ns->poll);
new_ns->user_ns = get_user_ns(user_ns);
new_ns->ucounts = ucounts;
@@ -3333,6 +3339,8 @@ struct mnt_namespace *copy_mnt_ns(unsigned long flags,
struct mnt_namespace *ns,
return new_ns;
namespace_lock();
+ list_add_tail(&new_ns->mntns_list, &all_mntns_list);
+
/* First pass: copy the tree topology */
copy_flags = CL_COPY_UNBINDABLE | CL_EXPIRE;
if (user_ns != ns->user_ns)
@@ -3400,6 +3408,9 @@ struct dentry *mount_subtree(struct vfsmount *m, const
char *name)
ns->root = mnt;
ns->mounts++;
list_add(&mnt->mnt_list, &ns->list);
+ namespace_lock();
+ list_add_tail(&ns->mntns_list, &all_mntns_list);
+ namespace_unlock();
err = vfs_path_lookup(m->mnt_root, m,
name, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
@@ -3691,6 +3702,9 @@ static void __init init_mount_tree(void)
ns->root = m;
ns->mounts = 1;
list_add(&m->mnt_list, &ns->list);
+ namespace_lock();
+ list_add_tail(&ns->mntns_list, &all_mntns_list);
+ namespace_unlock();
init_task.nsproxy->mnt_ns = ns;
get_mnt_ns(ns);
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