[CRIU] [PATCHv2 3/5] locks: Fix breaking lease type after dump

[Pavel Emelyanov]

On 08/14/2017 02:49 AM, Pavel Begunkov wrote:
> To restore breaking lease we should know 'target lease type' (see fcntl
> man), but it is always 'READ' in /proc. The patch sets correct lease
> type using fcntl(F_GETLEASE).
> 
> Signed-off-by: Pavel Begunkov <asml.silence at gmail.com>
> ---
>  criu/file-lock.c         | 26 +++++++++++++++++++++++++-
>  criu/files.c             |  3 +++
>  criu/include/file-lock.h |  1 +
>  3 files changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/criu/file-lock.c b/criu/file-lock.c
> index 0c5da70ca..5b0580782 100644
> --- a/criu/file-lock.c
> +++ b/criu/file-lock.c
> @@ -334,6 +334,30 @@ int note_file_lock(struct pid *pid, int fd, int lfd, struct fd_parms *p)
>  	return 0;
>  }
>  
> +int correct_file_leases_type(struct pid *pid, int fd, int lfd)
> +{
> +	struct file_lock *fl;
> +	int target_type;
> +
> +	list_for_each_entry(fl, &file_lock_list, list) {

I don't get why the list_for_each is here. The correct_file_leases_type() is done
right after note_file_lock which already walks the list of locks. Why not just re-use it?

> +		if (fl->fl_owner != pid->real || fl->owners_fd != fd)
> +			continue;
> +
> +		if (fl->fl_kind == FL_LEASE && fl->fl_ltype & LEASE_BREAKING) {

Please, add braces to the & operation.

> +			target_type = fcntl(lfd, F_GETLEASE);
> +			if (target_type < 0) {
> +				perror("Can't get lease type\n");
> +				return -1;
> +			}
> +
> +			fl->fl_ltype &= ~O_ACCMODE;
> +			fl->fl_ltype |= target_type;
> +			break;
> +		}
> +	}
> +	return 0;
> +}
> +
>  static int open_break_cb(int ns_root_fd, struct reg_file_info *rfi, void *arg)
>  {
>  	int fd, flags = *(int *)arg | O_NONBLOCK;
> @@ -365,7 +389,7 @@ static int set_lease_for_breaking(int fd, int fd_type)
>  	}
>  
>  	if (fcntl(fd, F_SETLEASE, lease_type) < 0) {
> -		pr_perror("Can't set lease to fd %#x\n", fd);
> +		pr_perror("Can't set lease (fd %i)\n", fd);

Merge this hunk into prev patch.

>  		return -1;
>  	}
>  	return 0;
> diff --git a/criu/files.c b/criu/files.c
> index 2c3389e3f..6c27e2e26 100644
> --- a/criu/files.c
> +++ b/criu/files.c
> @@ -459,6 +459,9 @@ static int dump_one_file(struct pid *pid, int fd, int lfd, struct fd_opts *opts,
>  	if (note_file_lock(pid, fd, lfd, &p))
>  		return -1;
>  
> +	if (correct_file_leases_type(pid, fd, lfd))
> +		return -1;
> +
>  	p.fd_ctl = ctl; /* Some dump_opts require this to talk to parasite */
>  
>  	if (S_ISSOCK(p.stat.st_mode))
> diff --git a/criu/include/file-lock.h b/criu/include/file-lock.h
> index 7280e0b55..7b19524d7 100644
> --- a/criu/include/file-lock.h
> +++ b/criu/include/file-lock.h
> @@ -68,6 +68,7 @@ extern struct collect_image_info file_locks_cinfo;
>  
>  struct pid;
>  struct fd_parms;
> +extern int correct_file_leases_type(struct pid *, int fd, int lfd);
>  extern int note_file_lock(struct pid *, int fd, int lfd, struct fd_parms *);
>  extern int dump_file_locks(void);
>  
>