From: Josef Bacik <josef@toxicpanda.com>
Date: Fri, 16 Oct 2020 15:29:15 +0000 (-0400)
Subject: btrfs: sysfs: export supported rescue= mount options
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ceafe3cc39923fc80b9091f3fd993e6de1b6a399;p=linux.git

btrfs: sysfs: export supported rescue= mount options

We're going to be adding a variety of different rescue options, we
should advertise which ones we support to make user spaces life easier
in the future.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 8424f5d0e5ed..8f0462d6855d 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -329,10 +329,32 @@ static ssize_t send_stream_version_show(struct kobject *kobj,
 }
 BTRFS_ATTR(static_feature, send_stream_version, send_stream_version_show);
 
+static const char *rescue_opts[] = {
+	"usebackuproot",
+	"nologreplay",
+};
+
+static ssize_t supported_rescue_options_show(struct kobject *kobj,
+					     struct kobj_attribute *a,
+					     char *buf)
+{
+	ssize_t ret = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(rescue_opts); i++)
+		ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+				 (i ? " " : ""), rescue_opts[i]);
+	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");
+	return ret;
+}
+BTRFS_ATTR(static_feature, supported_rescue_options,
+	   supported_rescue_options_show);
+
 static struct attribute *btrfs_supported_static_feature_attrs[] = {
 	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
 	BTRFS_ATTR_PTR(static_feature, supported_checksums),
 	BTRFS_ATTR_PTR(static_feature, send_stream_version),
+	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
 	NULL
 };