proc_parse: parse mnt_id from /proc/PID/fdinfo/FD

It will be used for restoring files from proper mounts.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files.c

@@ -205,7 +205,7 @@ static int fill_fd_params(struct parasite_ctl *ctl, int fd, int lfd,
 {
 	int ret;
 	struct statfs fsbuf;
-	struct fdinfo_common fdinfo;
+	struct fdinfo_common fdinfo = { .mnt_id = -1 };
 
 	if (fstat(lfd, &p->stat) < 0) {
 		pr_perror("Can't stat fd %d", lfd);

include/proc_parse.h

@@ -156,6 +156,7 @@ union fdinfo_entries {
 struct fdinfo_common {
 	off64_t pos;
 	int flags;
+	int mnt_id;
 };
 
 extern int parse_fdinfo(int fd, int type,

proc_parse.c

@@ -1021,7 +1021,8 @@ static int parse_fdinfo_pid_s(char *pid, int fd, int type,
 		union fdinfo_entries entry;
 
 		if (fdinfo_field(str, "pos") ||
-		    fdinfo_field(str, "flags")) {
+		    fdinfo_field(str, "flags") ||
+		    fdinfo_field(str, "mnt_id")) {
 			unsigned long long val;
 			struct fdinfo_common *fdinfo = arg;
 
@@ -1035,6 +1036,8 @@ static int parse_fdinfo_pid_s(char *pid, int fd, int type,
 				fdinfo->pos = val;
 			else if (fdinfo_field(str, "flags"))
 				fdinfo->flags = val;
+			else if (fdinfo_field(str, "mnt_id"))
+				fdinfo->mnt_id = val;
 
 			entry_met = true;
 			continue;