c/r: Add UTS support

c/r: Add UTS support

[Dan Smith]

This is the latest version of my patch set with changes in support of
feedback on version 6.

[PATCH 1/3] Make cr_may_checkpoint_task() check each namespace individually

[Dan Smith]

Cc: orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org
Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 checkpoint/checkpoint.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index ef35754..c2f0e16 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -302,8 +302,19 @@ static int cr_may_checkpoint_task(struct task_struct *t, struct cr_ctx *ctx)
 	if (t != current && !frozen(t))
 		return -EBUSY;
 
-	/* FIXME: change this for nested containers */
-	if (task_nsproxy(t) != ctx->root_nsproxy)
+	if (task_nsproxy(t)->uts_ns != ctx->root_nsproxy->uts_ns)
+		return -EPERM;
+
+	if (task_nsproxy(t)->ipc_ns != ctx->root_nsproxy->ipc_ns)
+		return -EPERM;
+
+	if (task_nsproxy(t)->mnt_ns != ctx->root_nsproxy->mnt_ns)
+		return -EPERM;
+
+	if (task_nsproxy(t)->pid_ns != ctx->root_nsproxy->pid_ns)
+		return -EPERM;
+
+	if (task_nsproxy(t)->net_ns != ctx->root_nsproxy->net_ns)
 		return -EPERM;
 
 	return 0;
-- 
1.5.6.3

[PATCH 2/3] c/r: Add UTS support (v7)

[Dan Smith]

This patch adds a "phase" of checkpoint that saves out information about any
namespaces the task(s) may have.  Do this by tracking the namespace objects
of the tasks and making sure that tasks with the same namespace that follow
get properly referenced in the checkpoint stream.

I tested this with single and multiple task restore, on top of Oren's
v13 tree.

Changes:
  - Remove the kernel restore path
  - Punt on nested namespaces
  - Use __NEW_UTS_LEN in nodename and domainname buffers
  - Add a note to Documentation/checkpoint/internals.txt to indicate where
    in the save/restore process the UTS information is kept
  - Store (and track) the objref of the namespace itself instead of the
    nsproxy (based on comments from Dave on IRC)
  - Remove explicit check for non-root nsproxy
  - Store the nodename and domainname lengths and use cr_write_string()
    to store the actual name strings
  - Catch failure of cr_obj_add_ptr() in cr_write_namespaces()
  - Remove "types" bitfield and use the "is this new" flag to determine
    whether or not we should write out a new ns descriptor
  - Replace kernel restore path
  - Move the namespace information to be directly after the task
    information record
  - Update Documentation to reflect new location of namespace info
  - Support checkpoint and restart of nested UTS namespaces
  - Check nodename and domainname length on restart (!)
  - memset() the nodename and domainname buffers on restart
  - Change uts to newuts in cr_write_namespaces()
  - Check return values of cr_hbuf_get()

Cc: orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org
Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 Documentation/checkpoint/internals.txt |    1 +
 checkpoint/Makefile                    |    1 +
 checkpoint/checkpoint.c                |   73 ++++++++++++++++++++-
 checkpoint/objhash.c                   |    7 ++
 checkpoint/restart.c                   |  111 ++++++++++++++++++++++++++++++++
 include/linux/checkpoint.h             |    1 +
 include/linux/checkpoint_hdr.h         |   11 +++
 7 files changed, 202 insertions(+), 3 deletions(-)

diff --git a/Documentation/checkpoint/internals.txt b/Documentation/checkpoint/internals.txt
index c741b6c..bdd202c 100644
--- a/Documentation/checkpoint/internals.txt
+++ b/Documentation/checkpoint/internals.txt
@@ -17,6 +17,7 @@ The order of operations, both save and restore, is as follows:
   -> thread state: elements of thread_struct and thread_info
   -> CPU state: registers etc, including FPU
   -> memory state: memory address space layout and contents
+  -> namespace information
   -> filesystem state: [TBD] filesystem namespace state, chroot, cwd, etc
   -> files state: open file descriptors and their state
   -> signals state: [TBD] pending signals and signal handling state
diff --git a/checkpoint/Makefile b/checkpoint/Makefile
index 607d864..55c5c3d 100644
--- a/checkpoint/Makefile
+++ b/checkpoint/Makefile
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_CHECKPOINT) += sys.o checkpoint.o restart.o objhash.o \
 		ckpt_mem.o rstr_mem.o ckpt_file.o rstr_file.o
+EXTRA_CFLAGS += -DDEBUG
diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index c2f0e16..ae0d3f8 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -213,6 +213,72 @@ static int cr_write_tail(struct cr_ctx *ctx)
 	return ret;
 }
 
+static int cr_write_utsns(struct cr_ctx *ctx, struct new_utsname *name)
+{
+	struct cr_hdr h;
+	struct cr_hdr_utsns *hh = cr_hbuf_get(ctx, sizeof(*hh));
+	int ret;
+
+	if (!hh)
+		return -ENOMEM;
+
+	h.type = CR_HDR_UTSNS;
+	h.len = sizeof(*hh);
+
+	hh->nodename_len = strlen(name->nodename) + 1;
+	hh->domainname_len = strlen(name->domainname) + 1;
+
+	ret = cr_write_obj(ctx, &h, hh);
+	if (ret < 0)
+		goto out;
+
+	ret = cr_write_string(ctx, name->nodename, hh->nodename_len);
+	if (ret < 0)
+		goto out;
+
+	ret = cr_write_string(ctx, name->domainname, hh->domainname_len);
+ out:
+	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_namespaces *hh = cr_hbuf_get(ctx, sizeof(*hh));
+	struct nsproxy *nsp = t->nsproxy;
+	int ret;
+	int newuts;
+
+	if (!hh)
+		return -ENOMEM;
+
+	h.type = CR_HDR_NS;
+	h.len = sizeof(*hh);
+
+	newuts = cr_obj_add_ptr(ctx, nsp->uts_ns, &hh->uts_ref,
+				CR_OBJ_UTSNS, 0);
+	if (newuts < 0)
+		goto out;
+
+	ret = cr_write_obj(ctx, &h, hh);
+	if (ret)
+		goto out;
+
+	if (newuts) {
+		ret = cr_write_utsns(ctx, &nsp->uts_ns->name);
+		if (ret < 0)
+			goto out;
+	}
+
+	/* FIXME: Write other namespaces here */
+ out:
+	cr_hbuf_put(ctx, sizeof(*hh));
+
+	return ret;
+}
+
 /* dump the task_struct of a given task */
 static int cr_write_task_struct(struct cr_ctx *ctx, struct task_struct *t)
 {
@@ -267,6 +333,10 @@ static int cr_write_task(struct cr_ctx *ctx, struct task_struct *t)
 		goto out;
 	ret = cr_write_cpu(ctx, t);
 	cr_debug("cpu: ret %d\n", ret);
+	if (ret < 0)
+		goto out;
+	ret = cr_write_namespaces(ctx, t);
+	cr_debug("ns: ret %d\n", ret);
  out:
 	return ret;
 }
@@ -302,9 +372,6 @@ static int cr_may_checkpoint_task(struct task_struct *t, struct cr_ctx *ctx)
 	if (t != current && !frozen(t))
 		return -EBUSY;
 
-	if (task_nsproxy(t)->uts_ns != ctx->root_nsproxy->uts_ns)
-		return -EPERM;
-
 	if (task_nsproxy(t)->ipc_ns != ctx->root_nsproxy->ipc_ns)
 		return -EPERM;
 
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index 25916c1..c6ae7c1 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;
@@ -38,6 +39,9 @@ static void cr_obj_ref_drop(struct cr_objref *obj)
 	case CR_OBJ_INODE:
 		iput((struct inode *) obj->ptr);
 		break;
+	case CR_OBJ_UTSNS:
+		put_uts_ns((struct uts_namespace *) obj->ptr);
+		break;
 	default:
 		BUG();
 	}
@@ -55,6 +59,9 @@ static int cr_obj_ref_grab(struct cr_objref *obj)
 		if (!igrab((struct inode *) obj->ptr))
 			ret = -EBADF;
 		break;
+	case CR_OBJ_UTSNS:
+		get_uts_ns((struct uts_namespace *) obj->ptr);
+		break;
 	default:
 		BUG();
 	}
diff --git a/checkpoint/restart.c b/checkpoint/restart.c
index adebc1c..1767460 100644
--- a/checkpoint/restart.c
+++ b/checkpoint/restart.c
@@ -15,6 +15,8 @@
 #include <linux/magic.h>
 #include <linux/checkpoint.h>
 #include <linux/checkpoint_hdr.h>
+#include <linux/utsname.h>
+#include <linux/syscalls.h>
 
 #include "checkpoint_arch.h"
 
@@ -236,6 +238,111 @@ static int cr_read_tail(struct cr_ctx *ctx)
 	return ret;
 }
 
+static int cr_read_utsns(struct cr_ctx *ctx, struct task_struct *t)
+{
+	struct cr_hdr_utsns hh;
+	struct uts_namespace *ns;
+	int ret;
+	char *nn = NULL;
+	char *dn = NULL;
+
+	ret = cr_read_obj_type(ctx, &hh, sizeof(hh), CR_HDR_UTSNS);
+	if (ret < 0)
+		return ret;
+
+	nn = kmalloc(hh.nodename_len, GFP_KERNEL);
+	if (!nn) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	dn = kmalloc(hh.domainname_len, GFP_KERNEL);
+	if (!dn) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	ret = cr_read_string(ctx, nn, hh.nodename_len);
+	if (ret < 0)
+		goto out;
+
+	ret = cr_read_string(ctx, dn, hh.domainname_len);
+	if (ret < 0)
+		goto out;
+
+	ret = sys_unshare(CLONE_NEWUTS);
+	if (ret)
+		goto out;
+
+	ns = t->nsproxy->uts_ns;
+
+	if ((hh.nodename_len > sizeof(ns->name.nodename)) ||
+	    (hh.domainname_len > sizeof(ns->name.domainname))) {
+		cr_debug("UTS field length too long\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	memset(ns->name.nodename, 0, sizeof(ns->name.nodename));
+	memset(ns->name.domainname, 0, sizeof(ns->name.domainname));
+	memcpy(ns->name.nodename, nn, hh.nodename_len);
+	memcpy(ns->name.domainname, dn, hh.domainname_len);
+
+ out:
+	kfree(nn);
+	kfree(dn);
+
+	return ret;
+}
+
+static int cr_restore_utsns(struct cr_ctx *ctx, int ref)
+{
+	struct uts_namespace *uts;
+	int ret;
+
+	uts = cr_obj_get_by_ref(ctx, ref, CR_OBJ_UTSNS);
+	if (uts == NULL) {
+		ret = cr_read_utsns(ctx, current);
+		if (ret < 0)
+			return ret;
+
+		return cr_obj_add_ref(ctx, current->nsproxy->uts_ns,
+				      ref, CR_OBJ_UTSNS, 0);
+	} else if (IS_ERR(uts)) {
+		cr_debug("Failed to get UTS ns from objhash");
+		return PTR_ERR(uts);
+	}
+
+	ret = copy_namespaces(CLONE_NEWUTS, current);
+	if (ret < 0)
+		return ret;
+
+	put_uts_ns(current->nsproxy->uts_ns);
+	get_uts_ns(uts);
+	current->nsproxy->uts_ns = uts;
+
+	return 0;
+}
+
+static int cr_read_namespaces(struct cr_ctx *ctx)
+{
+	struct cr_hdr_namespaces hh;
+	int ret;
+
+	ret = cr_read_obj_type(ctx, &hh, sizeof(hh), CR_HDR_NS);
+	if (ret < 0)
+		return ret;
+
+	ret = cr_restore_utsns(ctx, hh.uts_ref);
+	cr_debug("uts ns: %d\n", ret);
+	if (ret < 0)
+		return ret;
+
+	/* FIXME: Add more namespaces here */
+
+	return 0;
+}
+
 /* read the task_struct into the current task */
 static int cr_read_task_struct(struct cr_ctx *ctx)
 {
@@ -297,6 +404,10 @@ static int cr_read_task(struct cr_ctx *ctx)
 		goto out;
 	ret = cr_read_cpu(ctx);
 	cr_debug("cpu: ret %d\n", ret);
+	if (ret < 0)
+		goto out;
+	ret = cr_read_namespaces(ctx);
+	cr_debug("ns: ret %d\n", ret);
 
  out:
 	return ret;
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 59ec563..cf20746 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_INODE,
+	CR_OBJ_UTSNS,
 	CR_OBJ_MAX
 };
 
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 22b40a2..97f5761 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -48,6 +48,8 @@ enum {
 	CR_HDR_TASK,
 	CR_HDR_THREAD,
 	CR_HDR_CPU,
+	CR_HDR_NS,
+	CR_HDR_UTSNS,
 
 	CR_HDR_MM = 201,
 	CR_HDR_VMA,
@@ -184,4 +186,13 @@ struct cr_hdr_fd_pipe {
 	__s32 nr_bufs;
 } __attribute__((aligned(8)));
 
+struct cr_hdr_namespaces {
+	__u32 uts_ref;
+};
+
+struct cr_hdr_utsns {
+	__u32 nodename_len;
+	__u32 domainname_len;
+};
+
 #endif /* _CHECKPOINT_CKPT_HDR_H_ */
-- 
1.5.6.3

[PATCH 3/3] Stub implementation of IPC namespace c/r (v3)

[Dan Smith]

Changes:
 - Update to match UTS changes
 - Change ipc to newipc
 - Check return value of cr_hbuf_get()

Signed-off-by: Dan Smith <danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>
---
 checkpoint/checkpoint.c        |   30 ++++++++++++++++++++++++
 checkpoint/objhash.c           |    7 +++++
 checkpoint/restart.c           |   49 ++++++++++++++++++++++++++++++++++++++++
 include/linux/checkpoint.h     |    1 +
 include/linux/checkpoint_hdr.h |    6 +++++
 5 files changed, 93 insertions(+), 0 deletions(-)

diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index ae0d3f8..2212e21 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -243,6 +243,24 @@ static int cr_write_utsns(struct cr_ctx *ctx, struct new_utsname *name)
 	return ret;
 }
 
+static int cr_write_ipcns(struct cr_ctx *ctx, struct ipc_namespace *ipc)
+{
+	struct cr_hdr h;
+	struct cr_hdr_ipcns *hh = cr_hbuf_get(ctx, sizeof(*hh));
+	int ret;
+
+	if (!hh)
+		return -ENOMEM;
+
+	h.type = CR_HDR_IPCNS;
+	h.len = sizeof(*hh);
+
+	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;
@@ -250,6 +268,7 @@ static int cr_write_namespaces(struct cr_ctx *ctx, struct task_struct *t)
 	struct nsproxy *nsp = t->nsproxy;
 	int ret;
 	int newuts;
+	int newipc;
 
 	if (!hh)
 		return -ENOMEM;
@@ -262,6 +281,11 @@ static int cr_write_namespaces(struct cr_ctx *ctx, struct task_struct *t)
 	if (newuts < 0)
 		goto out;
 
+	newipc = cr_obj_add_ptr(ctx, nsp->ipc_ns, &hh->ipc_ref,
+				CR_OBJ_IPCNS, 0);
+	if (newipc < 0)
+		goto out;
+
 	ret = cr_write_obj(ctx, &h, hh);
 	if (ret)
 		goto out;
@@ -272,6 +296,12 @@ static int cr_write_namespaces(struct cr_ctx *ctx, struct task_struct *t)
 			goto out;
 	}
 
+	if (newipc) {
+		ret = cr_write_ipcns(ctx, nsp->ipc_ns);
+		if (ret < 0)
+			goto out;
+	}
+
 	/* FIXME: Write other namespaces here */
  out:
 	cr_hbuf_put(ctx, sizeof(*hh));
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index c6ae7c1..b04f8df 100644
--- a/checkpoint/objhash.c
+++ b/checkpoint/objhash.c
@@ -13,6 +13,7 @@
 #include <linux/hash.h>
 #include <linux/checkpoint.h>
 #include <linux/utsname.h>
+#include <linux/ipc_namespace.h>
 
 struct cr_objref {
 	int objref;
@@ -42,6 +43,9 @@ static void cr_obj_ref_drop(struct cr_objref *obj)
 	case CR_OBJ_UTSNS:
 		put_uts_ns((struct uts_namespace *) obj->ptr);
 		break;
+	case CR_OBJ_IPCNS:
+		put_ipc_ns((struct ipc_namespace *) obj->ptr);
+		break;
 	default:
 		BUG();
 	}
@@ -62,6 +66,9 @@ static int cr_obj_ref_grab(struct cr_objref *obj)
 	case CR_OBJ_UTSNS:
 		get_uts_ns((struct uts_namespace *) obj->ptr);
 		break;
+	case CR_OBJ_IPCNS:
+		get_ipc_ns((struct ipc_namespace *) obj->ptr);
+		break;
 	default:
 		BUG();
 	}
diff --git a/checkpoint/restart.c b/checkpoint/restart.c
index 1767460..3cb6786 100644
--- a/checkpoint/restart.c
+++ b/checkpoint/restart.c
@@ -16,6 +16,7 @@
 #include <linux/checkpoint.h>
 #include <linux/checkpoint_hdr.h>
 #include <linux/utsname.h>
+#include <linux/ipc_namespace.h>
 #include <linux/syscalls.h>
 
 #include "checkpoint_arch.h"
@@ -324,6 +325,49 @@ static int cr_restore_utsns(struct cr_ctx *ctx, int ref)
 	return 0;
 }
 
+static int cr_read_ipcns(struct cr_ctx *ctx, struct task_struct *t)
+{
+	struct cr_hdr_ipcns hh;
+	int ret;
+
+	ret = cr_read_obj_type(ctx, &hh, sizeof(hh), CR_HDR_IPCNS);
+	if (ret < 0)
+		return ret;
+
+	/* FIXME: Implement this */
+
+	return 0;
+}
+
+static int cr_restore_ipcns(struct cr_ctx *ctx, int ref)
+{
+	struct ipc_namespace *ipc;
+	int ret;
+
+	ipc = cr_obj_get_by_ref(ctx, ref, CR_OBJ_IPCNS);
+	if (ipc == NULL) {
+		ret = cr_read_ipcns(ctx, current);
+		if (ret < 0)
+			return ret;
+
+		return cr_obj_add_ref(ctx, current->nsproxy->ipc_ns,
+				      ref, CR_OBJ_IPCNS, 0);
+	} else if (IS_ERR(ipc)) {
+		cr_debug("Failed to get IPC ns from objhash\n");
+		return PTR_ERR(ipc);
+	}
+
+	ret = copy_namespaces(CLONE_NEWIPC, current);
+	if (ret < 0)
+		return ret;
+
+	put_ipc_ns(current->nsproxy->ipc_ns);
+	get_ipc_ns(ipc);
+	current->nsproxy->ipc_ns = ipc;
+
+	return 0;
+}
+
 static int cr_read_namespaces(struct cr_ctx *ctx)
 {
 	struct cr_hdr_namespaces hh;
@@ -338,6 +382,11 @@ static int cr_read_namespaces(struct cr_ctx *ctx)
 	if (ret < 0)
 		return ret;
 
+	ret = cr_restore_ipcns(ctx, hh.ipc_ref);
+	cr_debug("ipc ns: %d\n", ret);
+	if (ret < 0)
+		return ret;
+
 	/* FIXME: Add more namespaces here */
 
 	return 0;
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index cf20746..ba66bcf 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -76,6 +76,7 @@ enum {
 	CR_OBJ_FILE = 1,
 	CR_OBJ_INODE,
 	CR_OBJ_UTSNS,
+	CR_OBJ_IPCNS,
 	CR_OBJ_MAX
 };
 
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 97f5761..3ebbfd5 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -50,6 +50,7 @@ enum {
 	CR_HDR_CPU,
 	CR_HDR_NS,
 	CR_HDR_UTSNS,
+	CR_HDR_IPCNS,
 
 	CR_HDR_MM = 201,
 	CR_HDR_VMA,
@@ -188,6 +189,7 @@ struct cr_hdr_fd_pipe {
 
 struct cr_hdr_namespaces {
 	__u32 uts_ref;
+	__u32 ipc_ref;
 };
 
 struct cr_hdr_utsns {
@@ -195,4 +197,8 @@ struct cr_hdr_utsns {
 	__u32 domainname_len;
 };
 
+struct cr_hdr_ipcns {
+	/* FIXME: Fill this in */
+};
+
 #endif /* _CHECKPOINT_CKPT_HDR_H_ */
-- 
1.5.6.3

Re: c/r: Add UTS support

[Oren Laadan]

Hmm.. I already integrated the previous version to the current
dev branch (see branch ckpt-v14-rc3-dev ;  there are several
changed untested so I didn't release yet, but you can take a
look at the three corresponding patches.

BTW, in branch v14-rc3-dev of the userspace tool there is a
version of 'mktree' with the full algorithm for userspace task
creation.

Oren.

Dan Smith wrote:
> This is the latest version of my patch set with changes in support of
> feedback on version 6.
> 
> 
> _______________________________________________
> Containers mailing list
> Containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
> https://lists.linux-foundation.org/mailman/listinfo/containers
> 

Re: c/r: Add UTS support

[Dan Smith]

OL> Hmm.. I already integrated the previous version to the current dev
OL> branch (see branch ckpt-v14-rc3-dev ; there are several changed
OL> untested so I didn't release yet, but you can take a look at the
OL> three corresponding patches.

Okay, I can send a delta against rc3.

OL> BTW, in branch v14-rc3-dev of the userspace tool there is a
OL> version of 'mktree' with the full algorithm for userspace task
OL> creation.

Cool.

-- 
Dan Smith
IBM Linux Technology Center
email: danms-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org

c/r: Add UTS support

[Dan Smith]

This is the latest version of my UTS patch set.  It has been re-modified to
do restart in the kernel after much ponderage of the required algorithm
to do nested restart in userspace.  Thus, it no longer requires the
modified mktree.c from earlier sets.

The namespace information has been moved to follow the per-task
information in the checkpoint stream, per Oren's recommendation.

Checkpoint and restart of nested UTS namespaces is now supported.  In
support of that, the cr_may_checkpoint_task() function is updated to be
flexible about which namespaces must patch that of the root task.

The updated stub implementation of IPC namespace patch is included at
the end again.

c/r: Add UTS support

[Dan Smith]

This is the latest version of my UTS patch.  I think I integrated all
necessary feedback in the flurry of recent discussion.  My apologies if
I missed something.

This also adds the stub IPC namespace implementation, which right now
just writes an empty record.  Matching userspace support to follow.