bcachefs: bch2_opt_set_sb() can now set (some) device options

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/opts.c

@@ -617,10 +617,20 @@ int bch2_opts_from_sb(struct bch_opts *opts, struct bch_sb *sb)
 	return 0;
 }
 
-void __bch2_opt_set_sb(struct bch_sb *sb, const struct bch_option *opt, u64 v)
+struct bch_dev_sb_opt_set {
+	void			(*set_sb)(struct bch_member *, u64);
+};
+
+static const struct bch_dev_sb_opt_set bch2_dev_sb_opt_setters [] = {
+#define x(n, set)	[Opt_##n] = { .set_sb = SET_##set },
+	BCH_DEV_OPTS()
+#undef x
+};
+
+void __bch2_opt_set_sb(struct bch_sb *sb, int dev_idx,
+		       const struct bch_option *opt, u64 v)
 {
-	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
-		return;
+	enum bch_opt_id id = opt - bch2_opt_table;
 
 	if (opt->flags & OPT_SB_FIELD_SECTORS)
 		v >>= 9;
@@ -628,16 +638,30 @@ void __bch2_opt_set_sb(struct bch_sb *sb, const struct bch_option *opt, u64 v)
 	if (opt->flags & OPT_SB_FIELD_ILOG2)
 		v = ilog2(v);
 
+	if (opt->flags & OPT_FS) {
+		if (opt->set_sb != SET_BCH2_NO_SB_OPT)
 			opt->set_sb(sb, v);
-}
+	}
 
-void bch2_opt_set_sb(struct bch_fs *c, const struct bch_option *opt, u64 v)
-{
-	if (opt->set_sb == SET_BCH2_NO_SB_OPT)
+	if ((opt->flags & OPT_DEVICE) && dev_idx >= 0) {
+		if (WARN(!bch2_member_exists(sb, dev_idx),
+			 "tried to set device option %s on nonexistent device %i",
+			 opt->attr.name, dev_idx))
 			return;
 
+		struct bch_member *m = bch2_members_v2_get_mut(sb, dev_idx);
+
+		const struct bch_dev_sb_opt_set *set = bch2_dev_sb_opt_setters + id;
+		if (set->set_sb)
+			set->set_sb(m, v);
+	}
+}
+
+void bch2_opt_set_sb(struct bch_fs *c, struct bch_dev *ca,
+		     const struct bch_option *opt, u64 v)
+{
 	mutex_lock(&c->sb_lock);
-	__bch2_opt_set_sb(c->disk_sb.sb, opt, v);
+	__bch2_opt_set_sb(c->disk_sb.sb, ca ? ca->dev_idx : -1, opt, v);
 	bch2_write_super(c);
 	mutex_unlock(&c->sb_lock);
 }

fs/bcachefs/opts.h

@@ -490,6 +490,10 @@ enum fsck_err_opts {
 	  NULL,		"BTREE_ITER_prefetch casuse btree nodes to be\n"\
 	  " prefetched sequentially")
 
+#define BCH_DEV_OPTS()							\
+	x(discard,		BCH_MEMBER_DISCARD)			\
+	x(data_allowed,		BCH_MEMBER_DATA_ALLOWED)
+
 struct bch_opts {
 #define x(_name, _bits, ...)	unsigned _name##_defined:1;
 	BCH_OPTS()
@@ -569,8 +573,10 @@ void bch2_opt_set_by_id(struct bch_opts *, enum bch_opt_id, u64);
 
 u64 bch2_opt_from_sb(struct bch_sb *, enum bch_opt_id);
 int bch2_opts_from_sb(struct bch_opts *, struct bch_sb *);
-void __bch2_opt_set_sb(struct bch_sb *, const struct bch_option *, u64);
-void bch2_opt_set_sb(struct bch_fs *, const struct bch_option *, u64);
+void __bch2_opt_set_sb(struct bch_sb *, int, const struct bch_option *, u64);
+
+struct bch_dev;
+void bch2_opt_set_sb(struct bch_fs *, struct bch_dev *, const struct bch_option *, u64);
 
 int bch2_opt_lookup(const char *);
 int bch2_opt_validate(const struct bch_option *, u64, struct printbuf *);

fs/bcachefs/sysfs.c

@@ -674,7 +674,7 @@ STORE(bch2_fs_opts_dir)
 	if (ret < 0)
 		goto err;
 
-	bch2_opt_set_sb(c, opt, v);
+	bch2_opt_set_sb(c, NULL, opt, v);
 	bch2_opt_set_by_id(&c->opts, id, v);
 
 	if (v &&
@@ -826,14 +826,7 @@ STORE(bch2_dev)
 	if (attr == &sysfs_discard) {
 		bool v = strtoul_or_return(buf);
 
-		mutex_lock(&c->sb_lock);
-		mi = bch2_members_v2_get_mut(c->disk_sb.sb, ca->dev_idx);
-
-		if (v != BCH_MEMBER_DISCARD(mi)) {
-			SET_BCH_MEMBER_DISCARD(mi, v);
-			bch2_write_super(c);
-		}
-		mutex_unlock(&c->sb_lock);
+		bch2_opt_set_sb(c, ca, bch2_opt_table + Opt_discard, v);
 	}
 
 	if (attr == &sysfs_durability) {