[CRIU] [PATCH 01/10] files: split collect_fd on allocate_fd and handle_fd

[Pavel Emelyanov]

On 02/09/2017 11:10 AM, Andrei Vagin wrote:
> From: Andrew Vagin <avagin at virtuozzo.com>
> 
> We are going to open root directories for each namespace in
> the root task, so we need to collect all file descriptors to
> be able to find unused file descriptors.

In other words we need to call prepare_net_ns() after prepare_fd_pid(),
right?

But the former one is called from prepare_namespace() and the latter
from root_prepare_shared(), which in turn are both called from
restore_task_with_children() in the "wrong" order.

Maybe it's simpler to move prepare_net_ns() call out of prepare_namespaces()
into root_prepare_shared()'s end?

> Signed-off-by: Andrei Vagin <avagin at virtuozzo.com>
> ---
>  criu/cr-restore.c    | 18 ++++++++++++++++++
>  criu/files.c         | 50 +++++++++++++++++++++++++++++++++++++++++---------
>  criu/include/files.h |  1 +
>  3 files changed, 60 insertions(+), 9 deletions(-)
> 
> diff --git a/criu/cr-restore.c b/criu/cr-restore.c
> index 785d724..e7babe9 100644
> --- a/criu/cr-restore.c
> +++ b/criu/cr-restore.c
> @@ -1317,6 +1317,21 @@ static int create_children_and_session(void)
>  	return 0;
>  }
>  
> +static int collect_fd_shared()
> +{
> +	struct pstree_item *pi;
> +
> +	for_each_pstree_item(pi) {
> +		if (pi->pid->state == TASK_HELPER)
> +			continue;
> +
> +		if  (collect_fd_pid(pi))
> +			return -1;
> +	}
> +
> +	return 0;
> +}
> +
>  static int restore_task_with_children(void *_arg)
>  {
>  	struct cr_clone_arg *ca = _arg;
> @@ -1404,6 +1419,9 @@ static int restore_task_with_children(void *_arg)
>  		pr_info("Calling restore_sid() for init\n");
>  		restore_sid();
>  
> +		if (collect_fd_shared())
> +			goto err;
> +
>  		/*
>  		 * We need non /proc proc mount for restoring pid and mount
>  		 * namespaces and do not care for the rest of the cases.
> diff --git a/criu/files.c b/criu/files.c
> index 1a76313..4ef75b3 100644
> --- a/criu/files.c
> +++ b/criu/files.c
> @@ -686,19 +686,28 @@ int rst_file_params(int fd, FownEntry *fown, int flags)
>  	return 0;
>  }
>  
> -static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> +static struct fdinfo_list_entry *allocate_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
>  {
> -	struct fdinfo_list_entry *le, *new_le;
> -	struct file_desc *fdesc;
> +	struct fdinfo_list_entry *new_le;
>  
>  	pr_info("Collect fdinfo pid=%d fd=%d id=%#x\n",
>  		pid, e->fd, e->id);
>  
>  	new_le = shmalloc(sizeof(*new_le));
>  	if (!new_le)
> -		return -1;
> +		return NULL;
>  
>  	fle_init(new_le, pid, e);
> +	collect_task_fd(new_le, rst_info);
> +
> +	return new_le;
> +}
> +
> +static int handle_fd(struct fdinfo_list_entry *new_le, struct rst_info *rst_info)
> +{
> +	struct fdinfo_list_entry *le;
> +	struct file_desc *fdesc;
> +	FdinfoEntry *e = new_le->fe;
>  
>  	fdesc = find_file_desc(e);
>  	if (fdesc == NULL) {
> @@ -713,14 +722,23 @@ static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
>  	if (fdesc->ops->collect_fd)
>  		fdesc->ops->collect_fd(fdesc, new_le, rst_info);
>  
> -	collect_task_fd(new_le, rst_info);
> -
>  	list_add_tail(&new_le->desc_list, &le->desc_list);
>  	new_le->desc = fdesc;
>  
>  	return 0;
>  }
>  
> +static int collect_fd(int pid, FdinfoEntry *e, struct rst_info *rst_info)
> +{
> +	struct fdinfo_list_entry *le;
> +
> +	le = allocate_fd(pid, e, rst_info);
> +	if (le == NULL)
> +		return -1;
> +
> +	return handle_fd(le, rst_info);
> +}
> +
>  FdinfoEntry *dup_fdinfo(FdinfoEntry *old, int fd, unsigned flags)
>  {
>  	FdinfoEntry *e;
> @@ -777,7 +795,7 @@ int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id)
>  	return 0;
>  }
>  
> -int prepare_fd_pid(struct pstree_item *item)
> +int collect_fd_pid(struct pstree_item *item)
>  {
>  	int ret = 0;
>  	struct cr_img *img;
> @@ -798,6 +816,7 @@ int prepare_fd_pid(struct pstree_item *item)
>  		return -1;
>  
>  	while (1) {
> +		struct fdinfo_list_entry *le;
>  		FdinfoEntry *e;
>  
>  		ret = pb_read_one_eof(img, &e, PB_FDINFO);
> @@ -810,9 +829,10 @@ int prepare_fd_pid(struct pstree_item *item)
>  			break;
>  		}
>  
> -		ret = collect_fd(pid, e, rst_info);
> -		if (ret < 0) {
> +		le = allocate_fd(pid, e, rst_info);
> +		if (le == NULL) {
>  			fdinfo_entry__free_unpacked(e, NULL);
> +			ret = -1;
>  			break;
>  		}
>  	}
> @@ -821,6 +841,18 @@ int prepare_fd_pid(struct pstree_item *item)
>  	return ret;
>  }
>  
> +int prepare_fd_pid(struct pstree_item *item)
> +{
> +	struct rst_info *rst_info = rsti(item);
> +	struct fdinfo_list_entry *le, *t;
> +	list_for_each_entry_safe(le, t, &rst_info->fds, ps_list) {
> +		if (handle_fd(le, rst_info))
> +			return -1;
> +	}
> +
> +	return 0;
> +}
> +
>  #define SETFL_MASK (O_APPEND | O_ASYNC | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
>  int set_fd_flags(int fd, int flags)
>  {
> diff --git a/criu/include/files.h b/criu/include/files.h
> index 39ef23b..f1216a1 100644
> --- a/criu/include/files.h
> +++ b/criu/include/files.h
> @@ -156,6 +156,7 @@ extern int rst_file_params(int fd, FownEntry *fown, int flags);
>  extern void show_saved_files(void);
>  
>  extern int prepare_fds(struct pstree_item *me);
> +extern int collect_fd_pid(struct pstree_item *me);
>  extern int prepare_fd_pid(struct pstree_item *me);
>  extern int prepare_ctl_tty(int pid, struct rst_info *rst_info, u32 ctl_tty_id);
>  extern int prepare_shared_fdinfo(void);
>