[PATCH 26/30] cr: mount namespace
From: Alexey Dobriyan
Date: Thu Apr 09 2009 - 22:46:43 EST
This is one big FIXME:
What to do with overmounted files?
What to do with mounts at all, who should restore them?
just restore something to not oops on task exit
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
---
fs/namespace.c | 22 ++++++--
include/linux/cr.h | 6 ++
include/linux/mnt_namespace.h | 1
kernel/cr/Makefile | 1
kernel/cr/cpt-sys.c | 6 ++
kernel/cr/cr-mnt.c | 108 ++++++++++++++++++++++++++++++++++++++++++
kernel/cr/cr-nsproxy.c | 2
kernel/cr/cr.h | 4 +
8 files changed, 144 insertions(+), 6 deletions(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1970,6 +1970,21 @@ dput_out:
return retval;
}
+struct mnt_namespace *alloc_mnt_ns(void)
+{
+ struct mnt_namespace *mnt_ns;
+
+ mnt_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
+ if (mnt_ns) {
+ atomic_set(&mnt_ns->count, 1);
+ mnt_ns->root = NULL;
+ INIT_LIST_HEAD(&mnt_ns->list);
+ init_waitqueue_head(&mnt_ns->poll);
+ mnt_ns->event = 0;
+ }
+ return mnt_ns;
+}
+
/*
* Allocate a new namespace structure and populate it with contents
* copied from the namespace of the passed in task structure.
@@ -1981,15 +1996,10 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
struct vfsmount *rootmnt = NULL, *pwdmnt = NULL;
struct vfsmount *p, *q;
- new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
+ new_ns = alloc_mnt_ns();
if (!new_ns)
return ERR_PTR(-ENOMEM);
- atomic_set(&new_ns->count, 1);
- INIT_LIST_HEAD(&new_ns->list);
- init_waitqueue_head(&new_ns->poll);
- new_ns->event = 0;
-
down_write(&namespace_sem);
/* First pass: copy the tree topology */
new_ns->root = copy_tree(mnt_ns->root, mnt_ns->root->mnt_root,
--- a/include/linux/cr.h
+++ b/include/linux/cr.h
@@ -48,6 +48,7 @@ struct cr_object_header {
#define CR_OBJ_GROUP_INFO 17
#define CR_OBJ_USER_STRUCT 18
#define CR_OBJ_USER_NS 19
+#define CR_OBJ_MNT_NS 20
__u32 cr_type; /* object type */
__u32 cr_len; /* object length in bytes including header */
} __packed;
@@ -176,6 +177,7 @@ struct cr_image_nsproxy {
struct cr_object_header cr_hdr;
cr_pos_t cr_pos_uts_ns;
+ cr_pos_t cr_pos_mnt_ns;
cr_pos_t cr_pos_pid_ns;
} __packed;
@@ -190,6 +192,10 @@ struct cr_image_uts_ns {
__u8 cr_domainname[64];
} __packed;
+struct cr_image_mnt_ns {
+ struct cr_object_header cr_hdr;
+} __packed;
+
struct cr_image_pid_ns {
struct cr_object_header cr_hdr;
--- a/include/linux/mnt_namespace.h
+++ b/include/linux/mnt_namespace.h
@@ -24,6 +24,7 @@ struct proc_mounts {
struct fs_struct;
+struct mnt_namespace *alloc_mnt_ns(void);
extern struct mnt_namespace *copy_mnt_ns(unsigned long, struct mnt_namespace *,
struct fs_struct *);
extern void __put_mnt_ns(struct mnt_namespace *ns);
--- a/kernel/cr/Makefile
+++ b/kernel/cr/Makefile
@@ -5,6 +5,7 @@ cr-y += cr-cred.o
cr-y += cr-file.o
cr-y += cr-fs.o
cr-y += cr-mm.o
+cr-y += cr-mnt.o
cr-y += cr-nsproxy.o
cr-y += cr-pid.o
cr-y += cr-signal.o
--- a/kernel/cr/cpt-sys.c
+++ b/kernel/cr/cpt-sys.c
@@ -71,6 +71,9 @@ static int cr_collect(struct cr_context *ctx)
rv = cr_collect_all_uts_ns(ctx);
if (rv < 0)
return rv;
+ rv = cr_collect_all_mnt_ns(ctx);
+ if (rv < 0)
+ return rv;
rv = cr_collect_all_pid_ns(ctx);
if (rv < 0)
return rv;
@@ -158,6 +161,9 @@ static int cr_dump(struct cr_context *ctx)
rv = cr_dump_all_cred(ctx);
if (rv < 0)
return rv;
+ rv = cr_dump_all_mnt_ns(ctx);
+ if (rv < 0)
+ return rv;
rv = cr_dump_all_file(ctx);
if (rv < 0)
return rv;
new file mode 100644
--- /dev/null
+++ b/kernel/cr/cr-mnt.c
@@ -0,0 +1,108 @@
+/* Copyright (C) 2000-2009 Parallels Holdings, Ltd. */
+#include <linux/fs.h>
+#include <linux/mnt_namespace.h>
+
+#include <linux/cr.h>
+#include "cr.h"
+
+static int cr_collect_mnt_ns(struct cr_context *ctx, struct mnt_namespace *mnt_ns)
+{
+ int rv;
+
+ rv = cr_collect_object(ctx, mnt_ns, CR_CTX_MNT_NS);
+ printk("collect mnt_ns %p: rv %d\n", mnt_ns, rv);
+ return rv;
+}
+
+int cr_collect_all_mnt_ns(struct cr_context *ctx)
+{
+ struct cr_object *obj;
+ int rv;
+
+ for_each_cr_object(ctx, obj, CR_CTX_NSPROXY) {
+ struct nsproxy *nsproxy = obj->o_obj;
+
+ rv = cr_collect_mnt_ns(ctx, nsproxy->mnt_ns);
+ if (rv < 0)
+ return rv;
+ }
+ for_each_cr_object(ctx, obj, CR_CTX_MNT_NS) {
+ struct mnt_namespace *mnt_ns = obj->o_obj;
+ unsigned int cnt = atomic_read(&mnt_ns->count);
+
+ if (obj->o_count != cnt) {
+ printk("%s: mnt_ns %p has external references %lu:%u\n", __func__, mnt_ns, obj->o_count, cnt);
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int cr_dump_mnt_ns(struct cr_context *ctx, struct cr_object *obj)
+{
+ struct mnt_namespace *mnt_ns = obj->o_obj;
+ struct cr_image_mnt_ns *i;
+ int rv;
+
+ printk("dump mnt_ns %p\n", mnt_ns);
+
+ i = cr_prepare_image(CR_OBJ_MNT_NS, sizeof(*i));
+ if (!i)
+ return -ENOMEM;
+
+ obj->o_pos = ctx->cr_dump_file->f_pos;
+ rv = cr_write(ctx, i, sizeof(*i));
+ kfree(i);
+ return rv;
+}
+
+int cr_dump_all_mnt_ns(struct cr_context *ctx)
+{
+ struct cr_object *obj;
+ int rv;
+
+ for_each_cr_object(ctx, obj, CR_CTX_MNT_NS) {
+ rv = cr_dump_mnt_ns(ctx, obj);
+ if (rv < 0)
+ return rv;
+ }
+ return 0;
+}
+
+int cr_restore_mnt_ns(struct cr_context *ctx, loff_t pos)
+{
+ struct cr_image_mnt_ns *i;
+ struct mnt_namespace *mnt_ns;
+ struct cr_object *obj;
+ int rv;
+
+ i = kzalloc(sizeof(*i), GFP_KERNEL);
+ if (!i)
+ return -ENOMEM;
+ rv = cr_pread(ctx, i, sizeof(*i), pos);
+ if (rv < 0) {
+ kfree(i);
+ return rv;
+ }
+ if (i->cr_hdr.cr_type != CR_OBJ_MNT_NS) {
+ kfree(i);
+ return -EINVAL;
+ }
+
+ mnt_ns = alloc_mnt_ns();
+ if (!mnt_ns) {
+ kfree(i);
+ return -ENOMEM;
+ }
+ kfree(i);
+
+ obj = cr_object_create(mnt_ns);
+ if (!obj) {
+ kfree(mnt_ns);
+ return -ENOMEM;
+ }
+ obj->o_pos = pos;
+ list_add(&obj->o_list, &ctx->cr_obj[CR_CTX_MNT_NS]);
+ printk("restore mnt_ns %p, pos %lld\n", mnt_ns, (long long)pos);
+ return 0;
+}
--- a/kernel/cr/cr-nsproxy.c
+++ b/kernel/cr/cr-nsproxy.c
@@ -59,6 +59,8 @@ static int cr_dump_nsproxy(struct cr_context *ctx, struct cr_object *obj)
tmp = cr_find_obj_by_ptr(ctx, nsproxy->uts_ns, CR_CTX_UTS_NS);
i->cr_pos_uts_ns = tmp->o_pos;
+ tmp = cr_find_obj_by_ptr(ctx, nsproxy->mnt_ns, CR_CTX_MNT_NS);
+ i->cr_pos_mnt_ns = tmp->o_pos;
tmp = cr_find_obj_by_ptr(ctx, nsproxy->pid_ns, CR_CTX_PID_NS);
i->cr_pos_pid_ns = tmp->o_pos;
--- a/kernel/cr/cr.h
+++ b/kernel/cr/cr.h
@@ -28,6 +28,7 @@ enum cr_context_obj_type {
CR_CTX_FS_STRUCT,
CR_CTX_GROUP_INFO,
CR_CTX_MM_STRUCT,
+ CR_CTX_MNT_NS,
CR_CTX_NSPROXY,
CR_CTX_PID,
CR_CTX_PID_NS,
@@ -95,6 +96,7 @@ int cr_collect_all_file(struct cr_context *ctx);
int cr_collect_all_fs_struct(struct cr_context *ctx);
int cr_collect_all_group_info(struct cr_context *ctx);
int cr_collect_all_mm_struct(struct cr_context *ctx);
+int cr_collect_all_mnt_ns(struct cr_context *ctx);
int cr_collect_all_nsproxy(struct cr_context *ctx);
int cr_collect_all_pid_ns(struct cr_context *ctx);
int cr_collect_all_pid(struct cr_context *ctx);
@@ -111,6 +113,7 @@ int cr_dump_all_file(struct cr_context *ctx);
int cr_dump_all_fs_struct(struct cr_context *ctx);
int cr_dump_all_group_info(struct cr_context *ctx);
int cr_dump_all_mm_struct(struct cr_context *ctx);
+int cr_dump_all_mnt_ns(struct cr_context *ctx);
int cr_dump_all_nsproxy(struct cr_context *ctx);
int cr_dump_all_pid_ns(struct cr_context *ctx);
int cr_dump_all_pid(struct cr_context *ctx);
@@ -127,6 +130,7 @@ int cr_restore_file(struct cr_context *ctx, loff_t pos);
int cr_restore_fs_struct(struct cr_context *ctx, loff_t pos);
int cr_restore_group_info(struct cr_context *ctx, loff_t pos);
int cr_restore_mm_struct(struct cr_context *ctx, loff_t pos);
+int cr_restore_mnt_ns(struct cr_context *ctx, loff_t pos);
int cr_restore_nsproxy(struct cr_context *ctx, loff_t pos);
int cr_restore_pid_ns(struct cr_context *ctx, loff_t pos);
int cr_restore_pid(struct cr_context *ctx, struct cr_image_task_struct *i);
--
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