bcachefs: bch2_print_opts()

Make sure early error messages get redirected, for
kernel-fsck-from-userland.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/bcachefs.h

@@ -265,6 +265,9 @@ do {									\
 
 #define bch2_fmt(_c, fmt)		bch2_log_msg(_c, fmt "\n")
 
+__printf(2, 3)
+void bch2_print_opts(struct bch_opts *, const char *, ...);
+
 __printf(2, 3)
 void __bch2_print(struct bch_fs *c, const char *fmt, ...);
 

fs/bcachefs/super-io.c

@@ -717,6 +717,7 @@ static int __bch2_read_super(const char *path, struct bch_opts *opts,
 
 	if (IS_ERR(sb->bdev_handle)) {
 		ret = PTR_ERR(sb->bdev_handle);
+		prt_printf(&err, "error opening %s: %s", path, bch2_err_str(ret));
 		goto err;
 	}
 	sb->bdev = sb->bdev_handle->bdev;
@@ -743,9 +744,9 @@ static int __bch2_read_super(const char *path, struct bch_opts *opts,
 	prt_printf(&err2, "bcachefs (%s): error reading default superblock: %s\n",
 	       path, err.buf);
 	if (ret == -BCH_ERR_invalid_sb_magic && ignore_notbchfs_msg)
-		printk(KERN_INFO "%s", err2.buf);
+		bch2_print_opts(opts, KERN_INFO "%s", err2.buf);
 	else
-		printk(KERN_ERR "%s", err2.buf);
+		bch2_print_opts(opts, KERN_ERR "%s", err2.buf);
 
 	printbuf_exit(&err2);
 	printbuf_reset(&err);
@@ -808,16 +809,16 @@ static int __bch2_read_super(const char *path, struct bch_opts *opts,
 
 	ret = bch2_sb_validate(sb, &err, READ);
 	if (ret) {
-		printk(KERN_ERR "bcachefs (%s): error validating superblock: %s\n",
-		       path, err.buf);
+		bch2_print_opts(opts, KERN_ERR "bcachefs (%s): error validating superblock: %s\n",
+				path, err.buf);
 		goto err_no_print;
 	}
 out:
 	printbuf_exit(&err);
 	return ret;
 err:
-	printk(KERN_ERR "bcachefs (%s): error reading superblock: %s\n",
-	       path, err.buf);
+	bch2_print_opts(opts, KERN_ERR "bcachefs (%s): error reading superblock: %s\n",
+			path, err.buf);
 err_no_print:
 	bch2_free_super(sb);
 	goto out;

fs/bcachefs/super.c

@@ -87,6 +87,23 @@ const char * const bch2_fs_flag_strs[] = {
 	NULL
 };
 
+void bch2_print_opts(struct bch_opts *opts, const char *fmt, ...)
+{
+	struct stdio_redirect *stdio = (void *)(unsigned long)opts->stdio;
+
+	va_list args;
+	va_start(args, fmt);
+	if (likely(!stdio)) {
+		vprintk(fmt, args);
+	} else {
+		if (fmt[0] == KERN_SOH[0])
+			fmt += 2;
+
+		bch2_stdio_redirect_vprintf(stdio, true, fmt, args);
+	}
+	va_end(args);
+}
+
 void __bch2_print(struct bch_fs *c, const char *fmt, ...)
 {
 	struct stdio_redirect *stdio = bch2_fs_stdio_redirect(c);