journal: move code that checks for network fs to stat-util.[ch]

We have similar code in stat-util.[ch] and managing this at a central
place almost definitely is the better choice.

src/basic/stat-util.c

@@ -214,8 +214,19 @@ int path_is_fs_type(const char *path, statfs_f_type_t magic_value) {
 }
 
 bool is_temporary_fs(const struct statfs *s) {
-    return is_fs_type(s, TMPFS_MAGIC) ||
-           is_fs_type(s, RAMFS_MAGIC);
+        return is_fs_type(s, TMPFS_MAGIC) ||
+                is_fs_type(s, RAMFS_MAGIC);
+}
+
+bool is_network_fs(const struct statfs *s) {
+        return is_fs_type(s, CIFS_MAGIC_NUMBER) ||
+                is_fs_type(s, CODA_SUPER_MAGIC) ||
+                is_fs_type(s, NCP_SUPER_MAGIC) ||
+                is_fs_type(s, NFS_SUPER_MAGIC) ||
+                is_fs_type(s, SMB_SUPER_MAGIC) ||
+                is_fs_type(s, V9FS_MAGIC) ||
+                is_fs_type(s, AFS_SUPER_MAGIC) ||
+                is_fs_type(s, OCFS2_SUPER_MAGIC);
 }
 
 int fd_is_temporary_fs(int fd) {
@@ -227,15 +238,25 @@ int fd_is_temporary_fs(int fd) {
         return is_temporary_fs(&s);
 }
 
+int fd_is_network_fs(int fd) {
+        struct statfs s;
+
+        if (fstatfs(fd, &s) < 0)
+                return -errno;
+
+        return is_network_fs(&s);
+}
+
 int fd_is_network_ns(int fd) {
         int r;
 
         r = fd_is_fs_type(fd, NSFS_MAGIC);
         if (r <= 0)
                 return r;
-        r = ioctl(fd, NS_GET_NSTYPE);
-        if (r < 0)
+
+        if (ioctl(fd, NS_GET_NSTYPE) < 0)
                 return -errno;
+
         return r == CLONE_NEWNET;
 }