Quoting Dan Smith ([email protected]): > 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 <[email protected]> > --- > 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 > [email protected] > https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
