+struct fsck_thread {
+ struct thread_with_file thr;
+ struct printbuf buf;
+ struct bch_fs *c;
+ char **devs;
+ size_t nr_devs;
+ struct bch_opts opts;
+
+ struct log_output output;
+ DARRAY(char) output2;
+};
+
+static void bch2_fsck_thread_free(struct fsck_thread *thr)
+{
+ thread_with_file_exit(&thr->thr);
+ if (thr->devs)
+ for (size_t i = 0; i < thr->nr_devs; i++)
+ kfree(thr->devs[i]);
+ darray_exit(&thr->output2);
+ printbuf_exit(&thr->output.buf);
+ kfree(thr->devs);
+ kfree(thr);
+}
+
+static int bch2_fsck_thread_release(struct inode *inode, struct file *file)
+{
+ struct fsck_thread *thr = container_of(file->private_data, struct fsck_thread, thr);
+
+ bch2_fsck_thread_free(thr);
+ return 0;
+}
+
+static bool fsck_thread_ready(struct fsck_thread *thr)
+{
+ return thr->output.buf.pos ||
+ thr->output2.nr ||
+ thr->thr.done;
+}
+
+static ssize_t bch2_fsck_thread_read(struct file *file, char __user *buf,
+ size_t len, loff_t *ppos)
+{
+ struct fsck_thread *thr = container_of(file->private_data, struct fsck_thread, thr);
+ size_t copied = 0, b;
+ int ret = 0;
+
+ if ((file->f_flags & O_NONBLOCK) &&
+ !fsck_thread_ready(thr))
+ return -EAGAIN;
+
+ ret = wait_event_interruptible(thr->output.wait,
+ fsck_thread_ready(thr));
+ if (ret)
+ return ret;
+
+ if (thr->thr.done)
+ return 0;
+
+ while (len) {
+ ret = darray_make_room(&thr->output2, thr->output.buf.pos);
+ if (ret)
+ break;
+
+ spin_lock_irq(&thr->output.lock);
+ b = min_t(size_t, darray_room(thr->output2), thr->output.buf.pos);
+
+ memcpy(&darray_top(thr->output2), thr->output.buf.buf, b);
+ memmove(thr->output.buf.buf,
+ thr->output.buf.buf + b,
+ thr->output.buf.pos - b);
+
+ thr->output2.nr += b;
+ thr->output.buf.pos -= b;
+ spin_unlock_irq(&thr->output.lock);
+
+ b = min(len, thr->output2.nr);
+ if (!b)
+ break;
+
+ b -= copy_to_user(buf, thr->output2.data, b);
+ if (!b) {
+ ret = -EFAULT;
+ break;
+ }
+
+ copied += b;
+ buf += b;
+ len -= b;
+
+ memmove(thr->output2.data,
+ thr->output2.data + b,
+ thr->output2.nr - b);
+ thr->output2.nr -= b;
+ }
+
+ return copied ?: ret;
+}
+
+static __poll_t bch2_fsck_thread_poll(struct file *file, struct poll_table_struct *wait)
+{
+ struct fsck_thread *thr = container_of(file->private_data, struct fsck_thread, thr);
+
+ poll_wait(file, &thr->output.wait, wait);
+
+ return fsck_thread_ready(thr)
+ ? EPOLLIN|EPOLLHUP
+ : 0;
+}
+
+static const struct file_operations fsck_thread_ops = {
+ .release = bch2_fsck_thread_release,
+ .read = bch2_fsck_thread_read,
+ .poll = bch2_fsck_thread_poll,
+ .llseek = no_llseek,
+};
+
+static int bch2_fsck_offline_thread_fn(void *arg)
+{
+ struct fsck_thread *thr = container_of(arg, struct fsck_thread, thr);
+ struct bch_fs *c = bch2_fs_open(thr->devs, thr->nr_devs, thr->opts);
+
+ thr->thr.ret = PTR_ERR_OR_ZERO(c);
+ if (!thr->thr.ret)
+ bch2_fs_stop(c);
+
+ thr->thr.done = true;
+ wake_up(&thr->output.wait);
+ return 0;
+}
+
+static long bch2_ioctl_fsck_offline(struct bch_ioctl_fsck_offline __user *user_arg)
+{
+ struct bch_ioctl_fsck_offline arg;
+ struct fsck_thread *thr = NULL;
+ u64 *devs = NULL;
+ long ret = 0;
+
+ if (copy_from_user(&arg, user_arg, sizeof(arg)))
+ return -EFAULT;
+
+ if (arg.flags)
+ return -EINVAL;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!(devs = kcalloc(arg.nr_devs, sizeof(*devs), GFP_KERNEL)) ||
+ !(thr = kzalloc(sizeof(*thr), GFP_KERNEL)) ||
+ !(thr->devs = kcalloc(arg.nr_devs, sizeof(*thr->devs), GFP_KERNEL))) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ thr->opts = bch2_opts_empty();
+ thr->nr_devs = arg.nr_devs;
+ thr->output.buf = PRINTBUF;
+ thr->output.buf.atomic++;
+ spin_lock_init(&thr->output.lock);
+ init_waitqueue_head(&thr->output.wait);
+ darray_init(&thr->output2);
+
+ if (copy_from_user(devs, &user_arg->devs[0],
+ array_size(sizeof(user_arg->devs[0]), arg.nr_devs))) {
+ ret = -EINVAL;
+ goto err;
+ }
+
+ for (size_t i = 0; i < arg.nr_devs; i++) {
+ thr->devs[i] = strndup_user((char __user *)(unsigned long) devs[i], PATH_MAX);
+ ret = PTR_ERR_OR_ZERO(thr->devs[i]);
+ if (ret)
+ goto err;
+ }
+
+ if (arg.opts) {
+ char *optstr = strndup_user((char __user *)(unsigned long) arg.opts, 1 << 16);
+
+ ret = PTR_ERR_OR_ZERO(optstr) ?:
+ bch2_parse_mount_opts(NULL, &thr->opts, optstr);
+ kfree(optstr);
+
+ if (ret)
+ goto err;
+ }
+
+ opt_set(thr->opts, log_output, (u64)(unsigned long)&thr->output);
+
+ ret = run_thread_with_file(&thr->thr,
+ &fsck_thread_ops,
+ bch2_fsck_offline_thread_fn,
+ "bch-fsck");
+err:
+ if (ret < 0) {
+ if (thr)
+ bch2_fsck_thread_free(thr);
+ pr_err("ret %s", bch2_err_str(ret));
+ }
+ kfree(devs);
+ return ret;
+}
+