Quoting Dan Smith (danms@xxxxxxxxxx):
> This patch adds a "phase" of checkpoint that saves out information about any
> namespaces the task(s) may have. Do this by tracking the nsproxy of the
> first task and making sure that the tasks that follow get hooked back to
> share the same one on restart.
>
> Restart is handled in userspace by reading the UTS record(s), calling
> unshare() and setting the hostname accordingly. See my changes to
> mktree.c for details.
>
> I tested this with single and multiple task restore, on top of Oren's
> v13 tree.
Yeah this actually looks good to me.
Someone might complain about the per-task namespace data not showing
up in the per-task data, but I think the way you have it simplifies
things enough to justify it.
Do add a note to Documentation/checkpoint/internals.txt (and maybe
use __NEW_UTS_LEN+1 instead of 65), but other than that it looks
good to me.
thanks,
-serge
> Changes:
> - Remove the kernel restore path
> - Punt on nested namespaces
>
> Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
> ---
> checkpoint/checkpoint.c | 80 ++++++++++++++++++++++++++++++++++++++++
> checkpoint/objhash.c | 7 +++
> checkpoint/restart.c | 1 +
> include/linux/checkpoint.h | 1 +
> include/linux/checkpoint_hdr.h | 15 +++++++
> 5 files changed, 104 insertions(+), 0 deletions(-)
>
> diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
> index 64155de..12eb1d5 100644
> --- a/checkpoint/checkpoint.c
> +++ b/checkpoint/checkpoint.c
> @@ -193,6 +193,82 @@ static int cr_write_tail(struct cr_ctx *ctx)
> return ret;
> }
>
> +static int cr_write_ns_uts(struct cr_ctx *ctx, struct task_struct *t)
> +{
> + struct cr_hdr h;
> + struct cr_hdr_utsns *hh = cr_hbuf_get(ctx, sizeof(*hh));
> + struct new_utsname *n = &t->nsproxy->uts_ns->name;
> + int ret;
> +
> + h.type = CR_HDR_UTSNS;
> + h.len = sizeof(*hh);
> + h.parent = 0;
> +
> + memcpy(hh->nodename, n->nodename, sizeof(n->nodename));
> + memcpy(hh->domainname, n->domainname, sizeof(n->domainname));
> +
> + ret = cr_write_obj(ctx, &h, hh);
> + cr_hbuf_put(ctx, sizeof(*hh));
> +
> + return ret;
> +}
> +
> +static int cr_write_namespaces(struct cr_ctx *ctx, struct task_struct *t)
> +{
> + struct cr_hdr h;
> + struct cr_hdr_nsproxy *hh = cr_hbuf_get(ctx, sizeof(*hh));
> + struct nsproxy *nsp = t->nsproxy;
> + int ret;
> + int new;
> +
> + if (nsp != ctx->root_nsproxy) {
> + /* Don't allow checkpoint of nested namespaces yet */
> + pr_debug("Task has different nsproxy than root\n");
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + h.type = CR_HDR_NSP;
> + h.len = sizeof(*hh);
> + h.parent = 0;
> +
> + new = cr_obj_add_ptr(ctx, nsp, &hh->objref, CR_OBJ_NSP, 0);
> + if (new)
> + hh->types = CR_NSP_UTS; /* Record types we support */
> + else
> + hh->types = 0;
> +
> + ret = cr_write_obj(ctx, &h, hh);
> + if (ret)
> + goto out;
> +
> + if (new) {
> + ret = cr_write_ns_uts(ctx, t);
> + if (ret < 0)
> + goto out;
> +
> + /* FIXME: Write other namespaces here */
> + }
> + out:
> + cr_hbuf_put(ctx, sizeof(*hh));
> +
> + return ret;
> +}
> +
> +static int cr_write_all_namespaces(struct cr_ctx *ctx)
> +{
> + int n, ret = 0;
> +
> + for (n = 0; n < ctx->tasks_nr; n++) {
> + pr_debug("dumping ns for task #%d\n", n);
> + ret = cr_write_namespaces(ctx, ctx->tasks_arr[n]);
> + if (ret < 0)
> + break;
> + }
> +
> + return ret;
> +}
> +
> /* dump the task_struct of a given task */
> static int cr_write_task_struct(struct cr_ctx *ctx, struct task_struct *t)
> {
> @@ -549,6 +625,10 @@ int do_checkpoint(struct cr_ctx *ctx, pid_t pid)
> if (ret < 0)
> goto out;
>
> + ret = cr_write_all_namespaces(ctx);
> + if (ret < 0)
> + goto out;
> +
> ret = cr_write_all_tasks(ctx);
> if (ret < 0)
> goto out;
> diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
> index ee31b38..aaaf583 100644
> --- a/checkpoint/objhash.c
> +++ b/checkpoint/objhash.c
> @@ -12,6 +12,7 @@
> #include <linux/file.h>
> #include <linux/hash.h>
> #include <linux/checkpoint.h>
> +#include <linux/utsname.h>
>
> struct cr_objref {
> int objref;
> @@ -35,6 +36,9 @@ static void cr_obj_ref_drop(struct cr_objref *obj)
> case CR_OBJ_FILE:
> fput((struct file *) obj->ptr);
> break;
> + case CR_OBJ_NSP:
> + put_nsproxy((struct nsproxy *) obj->ptr);
> + break;
> default:
> BUG();
> }
> @@ -46,6 +50,9 @@ static void cr_obj_ref_grab(struct cr_objref *obj)
> case CR_OBJ_FILE:
> get_file((struct file *) obj->ptr);
> break;
> + case CR_OBJ_NSP:
> + get_nsproxy((struct nsproxy *) obj->ptr);
> + break;
> default:
> BUG();
> }
> diff --git a/checkpoint/restart.c b/checkpoint/restart.c
> index 7ec4de4..0ed01aa 100644
> --- a/checkpoint/restart.c
> +++ b/checkpoint/restart.c
> @@ -15,6 +15,7 @@
> #include <linux/magic.h>
> #include <linux/checkpoint.h>
> #include <linux/checkpoint_hdr.h>
> +#include <linux/utsname.h>
>
> #include "checkpoint_arch.h"
>
> diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
> index 217cf6e..5966275 100644
> --- a/include/linux/checkpoint.h
> +++ b/include/linux/checkpoint.h
> @@ -75,6 +75,7 @@ extern void cr_ctx_put(struct cr_ctx *ctx);
>
> enum {
> CR_OBJ_FILE = 1,
> + CR_OBJ_NSP,
> CR_OBJ_MAX
> };
>
> diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
> index 6dc739f..1413572 100644
> --- a/include/linux/checkpoint_hdr.h
> +++ b/include/linux/checkpoint_hdr.h
> @@ -49,6 +49,8 @@ enum {
> CR_HDR_TASK,
> CR_HDR_THREAD,
> CR_HDR_CPU,
> + CR_HDR_NSP,
> + CR_HDR_UTSNS,
>
> CR_HDR_MM = 201,
> CR_HDR_VMA,
> @@ -156,4 +158,17 @@ struct cr_hdr_fd_data {
> __u64 f_version;
> } __attribute__((aligned(8)));
>
> +#define CR_NSP_UTS 1
> +
> +struct cr_hdr_nsproxy {
> + __u32 objref;
> + __u32 types;
> +};
> +
> +struct cr_hdr_utsns {
> + /* Both of these fields are defined as 65-chars long */
> + char nodename[65];
> + char domainname[65];
> +};
> +
> #endif /* _CHECKPOINT_CKPT_HDR_H_ */
> --
> 1.5.6.3
>
> _______________________________________________
> Containers mailing list
> Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
> https://lists.linux-foundation.org/mailman/listinfo/containers
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/containers
