[CRIU] [PATCH] binfmt_misc: Skip dumping if it's not virtual

[Andrew Vagin]

On Mon, Dec 21, 2015 at 03:19:28PM +0300, Kirill Tkhai wrote:
> Similar to devtmpfs and devpts, skip binfmt_misc
> mount if it's not virtual.
>

Acked-by: Andrew Vagin <avagin at virtuozzo.com>

> Signed-off-by: Kirill Tkhai <ktkhai at odin.com>
> ---
>  include/fs-magic.h |    4 ++++
>  include/kerndat.h  |    1 +
>  kerndat.c          |    5 +++++
>  mount.c            |   12 +++++++++++-
>  4 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/include/fs-magic.h b/include/fs-magic.h
> index 777d736..d6e9e54 100644
> --- a/include/fs-magic.h
> +++ b/include/fs-magic.h
> @@ -45,4 +45,8 @@
>  #define PROC_SUPER_MAGIC	0x9fa0
>  #endif
>  
> +#ifndef BINFMTFS_MAGIC
> +#define BINFMTFS_MAGIC		0x42494e4d
> +#endif
> +
>  #endif /* __CR_FS_MAGIC_H__ */
> diff --git a/include/kerndat.h b/include/kerndat.h
> index e76b0d2..076804c 100644
> --- a/include/kerndat.h
> +++ b/include/kerndat.h
> @@ -32,6 +32,7 @@ extern struct kerndat_s kdat;
>  enum {
>  	KERNDAT_FS_STAT_DEVPTS,
>  	KERNDAT_FS_STAT_DEVTMPFS,
> +	KERNDAT_FS_STAT_BINFMT_MISC,
>  
>  	KERNDAT_FS_STAT_MAX
>  };
> diff --git a/kerndat.c b/kerndat.c
> index 5b9df83..4605470 100644
> --- a/kerndat.c
> +++ b/kerndat.c
> @@ -92,6 +92,11 @@ static dev_t get_host_dev(unsigned int which)
>  			.path	= "/dev",
>  			.magic	= TMPFS_MAGIC,
>  		},
> +		[KERNDAT_FS_STAT_BINFMT_MISC] = {
> +			.name	= "binfmt_misc",
> +			.path	= "/proc/sys/fs/binfmt_misc",
> +			.magic	= BINFMTFS_MAGIC,
> +		},
>  	};
>  
>  	if (which >= KERNDAT_FS_STAT_MAX) {
> diff --git a/mount.c b/mount.c
> index 2301b1f..8eedf5a 100644
> --- a/mount.c
> +++ b/mount.c
> @@ -1291,6 +1291,11 @@ static int devtmpfs_restore(struct mount_info *pm)
>  	return ret;
>  }
>  
> +static int binfmt_misc_virtual(struct mount_info *pm)
> +{
> +	return kerndat_fs_virtualized(KERNDAT_FS_STAT_BINFMT_MISC, pm->s_dev);
> +}
> +
>  static int parse_binfmt_misc_entry(struct bfd *f, BinfmtMiscEntry *bme)
>  {
>  	while (1) {
> @@ -1375,9 +1380,13 @@ static int dump_binfmt_misc_entry(int dfd, char *name, struct cr_img *img)
>  static int binfmt_misc_dump(struct mount_info *pm)
>  {
>  	struct cr_img *img;
> -	int fd, ret = -1;
>  	struct dirent *de;
>  	DIR *fdir = NULL;
> +	int fd, ret;
> +
> +	ret = binfmt_misc_virtual(pm);
> +	if (ret <= 0)
> +		return ret;
>  
>  	fd = open_mountpoint(pm);
>  	if (fd < 0)
> @@ -1389,6 +1398,7 @@ static int binfmt_misc_dump(struct mount_info *pm)
>  		return -1;
>  	}
>  
> +	ret = -1;
>  	img = open_image(CR_FD_BINFMT_MISC, O_DUMP, pm->s_dev);
>  	if (!img)
>  		goto out;
>