bcachefs: thread_with_file: add f_ops.flush

Add a flush op, to return the exit code via close().

Also update bcachefs usage to use this to return fsck exit codes.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/chardev.c

@@ -155,14 +155,28 @@ static void bch2_fsck_thread_exit(struct thread_with_stdio *_thr)
 	kfree(thr);
 }
 
-static void bch2_fsck_offline_thread_fn(struct thread_with_stdio *stdio)
+static int bch2_fsck_offline_thread_fn(struct thread_with_stdio *stdio)
 {
 	struct fsck_thread *thr = container_of(stdio, struct fsck_thread, thr);
 	struct bch_fs *c = bch2_fs_open(thr->devs, thr->nr_devs, thr->opts);
 
-	thr->thr.thr.ret = PTR_ERR_OR_ZERO(c);
-	if (!thr->thr.thr.ret)
-		bch2_fs_stop(c);
+	if (IS_ERR(c))
+		return PTR_ERR(c);
+
+	int ret = 0;
+	if (test_bit(BCH_FS_errors_fixed, &c->flags))
+		ret |= 1;
+	if (test_bit(BCH_FS_error, &c->flags))
+		ret |= 4;
+
+	bch2_fs_stop(c);
+
+	if (ret & 1)
+		bch2_stdio_redirect_printf(&stdio->stdio, false, "%s: errors fixed\n", c->name);
+	if (ret & 4)
+		bch2_stdio_redirect_printf(&stdio->stdio, false, "%s: still has errors\n", c->name);
+
+	return ret;
 }
 
 static const struct thread_with_stdio_ops bch2_offline_fsck_ops = {
@@ -763,7 +777,7 @@ static long bch2_ioctl_disk_resize_journal(struct bch_fs *c,
 	return ret;
 }
 
-static void bch2_fsck_online_thread_fn(struct thread_with_stdio *stdio)
+static int bch2_fsck_online_thread_fn(struct thread_with_stdio *stdio)
 {
 	struct fsck_thread *thr = container_of(stdio, struct fsck_thread, thr);
 	struct bch_fs *c = thr->c;
@@ -795,6 +809,7 @@ static void bch2_fsck_online_thread_fn(struct thread_with_stdio *stdio)
 
 	up(&c->online_fsck_mutex);
 	bch2_ro_ref_put(c);
+	return ret;
 }
 
 static const struct thread_with_stdio_ops bch2_online_fsck_ops = {

fs/bcachefs/thread_with_file.c

@@ -247,6 +247,14 @@ static __poll_t thread_with_stdout_poll(struct file *file, struct poll_table_str
 	return mask;
 }
 
+static int thread_with_stdio_flush(struct file *file, fl_owner_t id)
+{
+	struct thread_with_stdio *thr =
+		container_of(file->private_data, struct thread_with_stdio, thr);
+
+	return thr->thr.ret;
+}
+
 static long thread_with_stdio_ioctl(struct file *file, unsigned int cmd, unsigned long p)
 {
 	struct thread_with_stdio *thr =
@@ -262,6 +270,7 @@ static const struct file_operations thread_with_stdio_fops = {
 	.read		= thread_with_stdio_read,
 	.write		= thread_with_stdio_write,
 	.poll		= thread_with_stdio_poll,
+	.flush		= thread_with_stdio_flush,
 	.release	= thread_with_stdio_release,
 	.unlocked_ioctl	= thread_with_stdio_ioctl,
 };
@@ -270,6 +279,7 @@ static const struct file_operations thread_with_stdout_fops = {
 	.llseek		= no_llseek,
 	.read		= thread_with_stdio_read,
 	.poll		= thread_with_stdout_poll,
+	.flush		= thread_with_stdio_flush,
 	.release	= thread_with_stdio_release,
 	.unlocked_ioctl	= thread_with_stdio_ioctl,
 };
@@ -278,7 +288,7 @@ static int thread_with_stdio_fn(void *arg)
 {
 	struct thread_with_stdio *thr = arg;
 
-	thr->ops->fn(thr);
+	thr->thr.ret = thr->ops->fn(thr);
 
 	thread_with_stdio_done(thr);
 	return 0;

fs/bcachefs/thread_with_file.h

@@ -53,7 +53,7 @@ struct thread_with_stdio;
 
 struct thread_with_stdio_ops {
 	void (*exit)(struct thread_with_stdio *);
-	void (*fn)(struct thread_with_stdio *);
+	int (*fn)(struct thread_with_stdio *);
 	long (*unlocked_ioctl)(struct thread_with_stdio *, unsigned int, unsigned long);
 };