+ " -p Automatic repair (no questions)\n"
+ " -n Don't repair, only check for errors\n"
+ " -y Assume \"yes\" to all questions\n"
+ " -f Force checking even if filesystem is marked clean\n"
+ " -r, --ratelimit_errors Don't display more than 10 errors of a given type\n"
+ " -R, --reconstruct_alloc Reconstruct the alloc btree\n"
+ " -k, --kernel Use the in-kernel fsck implementation\n"
+ " -v Be verbose\n"
+ " -h, --help Display this help and exit\n"
+ "Report bugs to <linux-bcachefs@vger.kernel.org>");
+}
+
+static void setnonblocking(int fd)
+{
+ int flags = fcntl(fd, F_GETFL);
+ if (fcntl(fd, F_SETFL, flags|O_NONBLOCK))
+ die("fcntl error: %m");
+}
+
+static int do_splice(int rfd, int wfd)
+{
+ char buf[4096], *b = buf;
+
+ int r = read(rfd, buf, sizeof(buf));
+ if (r < 0 && errno == EAGAIN)
+ return 0;
+ if (r < 0)
+ return r;
+ if (!r)
+ return 1;
+ do {
+ ssize_t w = write(wfd, b, r);
+ if (w < 0)
+ die("%s: write error: %m", __func__);
+ r -= w;
+ b += w;
+ } while (r);
+ return 0;
+}
+
+static int splice_fd_to_stdinout(int fd)
+{
+ setnonblocking(STDIN_FILENO);
+ setnonblocking(fd);
+
+ while (true) {
+ fd_set fds;
+
+ FD_ZERO(&fds);
+ FD_SET(STDIN_FILENO, &fds);
+ FD_SET(fd, &fds);
+
+ select(fd + 1, &fds, NULL, NULL, NULL);
+
+ int r = do_splice(fd, STDOUT_FILENO) ?:
+ do_splice(STDIN_FILENO, fd);
+ if (r)
+ return r < 0 ? r : 0;
+ }
+
+ return 0;
+}
+
+static int fsck_online(const char *dev_path)
+{
+ int dev_idx;
+ struct bchfs_handle fs = bchu_fs_open_by_dev(dev_path, &dev_idx);
+
+ struct bch_ioctl_fsck_online fsck = { 0 };
+
+ int fsck_fd = ioctl(fs.ioctl_fd, BCH_IOCTL_FSCK_ONLINE, &fsck);
+ if (fsck_fd < 0)
+ die("BCH_IOCTL_FSCK_ONLINE error: %s", bch2_err_str(fsck_fd));
+
+ return splice_fd_to_stdinout(fsck_fd);
+}
+
+static void append_opt(struct printbuf *out, const char *opt)
+{
+ if (out->pos)
+ prt_char(out, ',');
+ prt_str(out, opt);