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Subject[PATCH 27/38] C/R: checkpoint/restore struct uts_namespace
Date
The simplest thing.

Note, no locking is done, because we know:
a) tasks are frozen and thus can't change it
b) number of collected references is correct, so nobody else
is using uts_namespace and thus can't change it under dump

If live checkpointing will be done, code will be changed
to something like:

if (ctx->dump_live)
down_read(&uts_sem);
...
if (ctx->dump_live)
up_read(&uts_sem);
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
include/linux/kstate-image.h | 14 +++++
include/linux/kstate.h | 5 ++
kernel/kstate/cpt-sys.c | 6 ++
kernel/kstate/kstate-context.c | 6 ++
kernel/kstate/kstate-object.c | 4 ++
kernel/nsproxy.c | 33 +++++++++++--
kernel/utsname.c | 106 ++++++++++++++++++++++++++++++++++++++++
7 files changed, 170 insertions(+), 4 deletions(-)
delete mode 100644 kernel/kstate/kstate-nsproxy.c
create mode 100644 kernel/kstate/kstate-uts_ns.c
diff --git a/include/linux/kstate-image.h b/include/linux/kstate-image.h
index b8263c8..2eef50b 100644
--- a/include/linux/kstate-image.h
+++ b/include/linux/kstate-image.h
@@ -44,6 +44,7 @@ struct kstate_image_header {
#define KSTATE_OBJ_VMA 4
#define KSTATE_OBJ_PAGE 5
#define KSTATE_OBJ_NSPROXY 6
+#define KSTATE_OBJ_UTS_NS 7

struct kstate_object_header {
__u32 obj_type;
@@ -208,5 +209,18 @@ struct kstate_image_file {

struct kstate_image_nsproxy {
struct kstate_object_header hdr;
+
+ kstate_ref_t ref_uts_ns;
+} __packed;
+
+struct kstate_image_uts_ns {
+ struct kstate_object_header hdr;
+
+ __u8 sysname[64];
+ __u8 nodename[64];
+ __u8 release[64];
+ __u8 version[64];
+ __u8 machine[64];
+ __u8 domainname[64];
} __packed;
#endif
diff --git a/include/linux/kstate.h b/include/linux/kstate.h
index bd5c9f1..dba4803 100644
--- a/include/linux/kstate.h
+++ b/include/linux/kstate.h
@@ -25,6 +25,7 @@ enum kstate_context_obj_type {
KSTATE_CTX_MM_STRUCT,
KSTATE_CTX_NSPROXY,
KSTATE_CTX_TASK_STRUCT,
+ KSTATE_CTX_UTS_NS,
NR_KSTATE_CTX_TYPES
};

@@ -72,6 +73,10 @@ int kstate_collect_all_nsproxy(struct kstate_context *ctx);
int kstate_dump_all_nsproxy(struct kstate_context *ctx);
int kstate_restore_nsproxy(struct kstate_context *ctx, kstate_ref_t *ref);

+int kstate_collect_all_uts_ns(struct kstate_context *ctx);
+int kstate_dump_all_uts_ns(struct kstate_context *ctx);
+int kstate_restore_uts_ns(struct kstate_context *ctx, kstate_ref_t *ref);
+
#if defined(CONFIG_X86_32) || defined(CONFIG_X86_64)
extern const __u32 kstate_kernel_arch;
int kstate_arch_check_image_header(struct kstate_image_header *i);
diff --git a/kernel/kstate/cpt-sys.c b/kernel/kstate/cpt-sys.c
index 1d5e79d..7d4681a 100644
--- a/kernel/kstate/cpt-sys.c
+++ b/kernel/kstate/cpt-sys.c
@@ -68,6 +68,9 @@ static int kstate_collect(struct kstate_context *ctx)
rv = kstate_collect_all_nsproxy(ctx);
if (rv < 0)
return rv;
+ rv = kstate_collect_all_uts_ns(ctx);
+ if (rv < 0)
+ return rv;
rv = kstate_collect_all_mm_struct(ctx);
if (rv < 0)
return rv;
@@ -130,6 +133,9 @@ static int kstate_dump(struct kstate_context *ctx)
rv = kstate_dump_all_mm_struct(ctx);
if (rv < 0)
return rv;
+ rv = kstate_dump_all_uts_ns(ctx);
+ if (rv < 0)
+ return rv;
rv = kstate_dump_all_nsproxy(ctx);
if (rv < 0)
return rv;
diff --git a/kernel/kstate/kstate-context.c b/kernel/kstate/kstate-context.c
index 8c728f5..98dc0c0 100644
--- a/kernel/kstate/kstate-context.c
+++ b/kernel/kstate/kstate-context.c
@@ -4,6 +4,7 @@
#include <linux/nsproxy.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/utsname.h>

#include <linux/kstate.h>

@@ -51,5 +52,10 @@ void kstate_context_destroy(struct kstate_context *ctx)
list_del(&obj->o_list);
kfree(obj);
}
+ for_each_kstate_object_safe(ctx, obj, tmp, KSTATE_CTX_UTS_NS) {
+ put_uts_ns((struct uts_namespace *)obj->o_obj);
+ list_del(&obj->o_list);
+ kfree(obj);
+ }
kfree(ctx);
}
diff --git a/kernel/kstate/kstate-nsproxy.c b/kernel/kstate/kstate-nsproxy.c
deleted file mode 100644
index e69de29..0000000
diff --git a/kernel/kstate/kstate-object.c b/kernel/kstate/kstate-object.c
index 078bd36..aeadd95 100644
--- a/kernel/kstate/kstate-object.c
+++ b/kernel/kstate/kstate-object.c
@@ -4,6 +4,7 @@
#include <linux/nsproxy.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/utsname.h>

#include <linux/kstate.h>
#include <linux/kstate-image.h>
@@ -42,6 +43,9 @@ int kstate_collect_object(struct kstate_context *ctx, void *p, enum kstate_conte
case KSTATE_CTX_TASK_STRUCT:
get_task_struct((struct task_struct *)obj->o_obj);
break;
+ case KSTATE_CTX_UTS_NS:
+ get_uts_ns((struct uts_namespace *)obj->o_obj);
+ break;
default:
BUG();
}
diff --git a/kernel/kstate/kstate-uts_ns.c b/kernel/kstate/kstate-uts_ns.c
new file mode 100644
index 0000000..e69de29
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b7ccd68..b2a7ed3 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -271,12 +271,16 @@ static int dump_nsproxy(struct kstate_context *ctx, struct kstate_object *obj)
{
struct nsproxy *nsproxy = obj->o_obj;
struct kstate_image_nsproxy *i;
+ struct kstate_object *tmp;
int rv;

i = kstate_prepare_image(KSTATE_OBJ_NSPROXY, sizeof(*i));
if (!i)
return -ENOMEM;

+ tmp = find_kstate_obj_by_ptr(ctx, nsproxy->uts_ns, KSTATE_CTX_UTS_NS);
+ i->ref_uts_ns = tmp->o_ref;
+
rv = kstate_write_image(ctx, i, sizeof(*i), obj);
kfree(i);
pr_debug("dump nsproxy %p: ref {%llu, %u}, rv %d\n", nsproxy, (unsigned long long)obj->o_ref.pos, obj->o_ref.id, rv);
@@ -296,11 +300,30 @@ int kstate_dump_all_nsproxy(struct kstate_context *ctx)
return 0;
}

+static int restore_uts_ns(struct kstate_context *ctx, kstate_ref_t *ref, struct nsproxy *nsproxy)
+{
+ struct uts_namespace *uts_ns;
+ struct kstate_object *tmp;
+ int rv;
+
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_UTS_NS);
+ if (!tmp) {
+ rv = kstate_restore_uts_ns(ctx, ref);
+ if (rv < 0)
+ return rv;
+ tmp = find_kstate_obj_by_ref(ctx, ref, KSTATE_CTX_UTS_NS);
+ }
+ uts_ns = tmp->o_obj;
+
+ get_uts_ns(uts_ns);
+ nsproxy->uts_ns = uts_ns;
+ return 0;
+}
+
int kstate_restore_nsproxy(struct kstate_context *ctx, kstate_ref_t *ref)
{
struct kstate_image_nsproxy *i;
struct nsproxy *nsproxy;
- struct uts_namespace *uts_ns;
#ifdef CONFIG_IPC_NS
struct ipc_namespace *ipc_ns;
#endif
@@ -321,9 +344,9 @@ int kstate_restore_nsproxy(struct kstate_context *ctx, kstate_ref_t *ref)
goto out_free_image;
}

- uts_ns = ctx->init_tsk->nsproxy->uts_ns;
- get_uts_ns(uts_ns);
- nsproxy->uts_ns = uts_ns;
+ rv = restore_uts_ns(ctx, &i->ref_uts_ns, nsproxy);
+ if (rv < 0)
+ goto out_uts_ns;

#ifdef CONFIG_IPC_NS
ipc_ns = ctx->init_tsk->nsproxy->ipc_ns;
@@ -349,6 +372,8 @@ int kstate_restore_nsproxy(struct kstate_context *ctx, kstate_ref_t *ref)
pr_debug("restore nsproxy %p, ref {%llu, %u}, rv %d\n", nsproxy, (unsigned long long)ref->pos, ref->id, rv);
return rv;

+out_uts_ns:
+ kmem_cache_free(nsproxy_cachep, nsproxy);
out_free_image:
kfree(i);
pr_debug("%s: return %d, ref {%llu, %u}\n", __func__, rv, (unsigned long long)ref->pos, ref->id);
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 8a82b4b..5b25e8d 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2004 IBM Corporation
+ * Copyright (C) 2009 Parallels Holdings, Ltd.
*
* Author: Serge Hallyn <serue@us.ibm.com>
*
@@ -73,3 +74,108 @@ void free_uts_ns(struct kref *kref)
ns = container_of(kref, struct uts_namespace, kref);
kfree(ns);
}
+
+#ifdef CONFIG_CHECKPOINT
+#include <linux/kstate.h>
+#include <linux/kstate-image.h>
+
+static int collect_uts_ns(struct kstate_context *ctx, struct uts_namespace *uts_ns)
+{
+ int rv;
+
+ rv = kstate_collect_object(ctx, uts_ns, KSTATE_CTX_UTS_NS);
+ pr_debug("collect uts_ns %p: rv %d\n", uts_ns, rv);
+ return rv;
+}
+
+int kstate_collect_all_uts_ns(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_NSPROXY) {
+ struct nsproxy *nsproxy = obj->o_obj;
+
+ rv = collect_uts_ns(ctx, nsproxy->uts_ns);
+ if (rv < 0)
+ return rv;
+ }
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_UTS_NS) {
+ struct uts_namespace *uts_ns = obj->o_obj;
+ unsigned int cnt = atomic_read(&uts_ns->kref.refcount);
+
+ if (obj->o_count + 1 != cnt) {
+ pr_err("uts_ns %p has external references %lu:%u\n", uts_ns, obj->o_count, cnt);
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int dump_uts_ns(struct kstate_context *ctx, struct kstate_object *obj)
+{
+ struct uts_namespace *uts_ns = obj->o_obj;
+ struct kstate_image_uts_ns *i;
+ int rv;
+
+ i = kstate_prepare_image(KSTATE_OBJ_UTS_NS, sizeof(*i));
+ if (!i)
+ return -ENOMEM;
+
+ strncpy(i->sysname, (const char *)uts_ns->name.sysname, 64);
+ strncpy(i->nodename, (const char *)uts_ns->name.nodename, 64);
+ strncpy(i->release, (const char *)uts_ns->name.release, 64);
+ strncpy(i->version, (const char *)uts_ns->name.version, 64);
+ strncpy(i->machine, (const char *)uts_ns->name.machine, 64);
+ strncpy(i->domainname, (const char *)uts_ns->name.domainname, 64);
+
+ rv = kstate_write_image(ctx, i, sizeof(*i), obj);
+ kfree(i);
+ pr_debug("dump uts_ns %p: ref {%llu, %u}, rv %d\n", uts_ns, (unsigned long long)obj->o_ref.pos, obj->o_ref.id, rv);
+ return rv;
+}
+
+int kstate_dump_all_uts_ns(struct kstate_context *ctx)
+{
+ struct kstate_object *obj;
+ int rv;
+
+ for_each_kstate_object(ctx, obj, KSTATE_CTX_UTS_NS) {
+ rv = dump_uts_ns(ctx, obj);
+ if (rv < 0)
+ return rv;
+ }
+ return 0;
+}
+
+int kstate_restore_uts_ns(struct kstate_context *ctx, kstate_ref_t *ref)
+{
+ struct kstate_image_uts_ns *i;
+ struct uts_namespace *uts_ns;
+ int rv;
+
+ i = kstate_read_image(ctx, ref, KSTATE_OBJ_UTS_NS, sizeof(*i));
+ if (IS_ERR(i))
+ return PTR_ERR(i);
+
+ uts_ns = create_uts_ns();
+ if (!uts_ns) {
+ kfree(i);
+ return -ENOMEM;
+ }
+
+ strlcpy(uts_ns->name.sysname, i->sysname, sizeof(uts_ns->name.sysname));
+ strlcpy(uts_ns->name.nodename, i->nodename, sizeof(uts_ns->name.nodename));
+ strlcpy(uts_ns->name.release, i->release, sizeof(uts_ns->name.release));
+ strlcpy(uts_ns->name.version, i->version, sizeof(uts_ns->name.version));
+ strlcpy(uts_ns->name.machine, i->machine, sizeof(uts_ns->name.machine));
+ strlcpy(uts_ns->name.domainname, i->domainname, sizeof(uts_ns->name.domainname));
+ kfree(i);
+
+ rv = kstate_restore_object(ctx, uts_ns, KSTATE_CTX_UTS_NS, ref);
+ if (rv < 0)
+ put_uts_ns(uts_ns);
+ pr_debug("restore uts_ns %p: ref {%llu, %u}, rv %d\n", uts_ns, (unsigned long long)ref->pos, ref->id, rv);
+ return rv;
+}
+#endif
--
1.5.6.5


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