1 files changed, 26 insertions, 12 deletions

diff --git a/libbcachefs/super.c b/libbcachefs/super.c
index 96264686..18d8823c 100644
--- a/libbcachefs/super.c
+++ b/libbcachefs/super.c
@@ -214,7 +214,6 @@ static int bch2_dev_sysfs_online(struct bch_fs *, struct bch_dev *);
 static void bch2_dev_io_ref_stop(struct bch_dev *, int);
 static void __bch2_dev_read_only(struct bch_fs *, struct bch_dev *);
 static int bch2_fs_init_rw(struct bch_fs *);
-static int bch2_fs_resize_on_mount(struct bch_fs *);
 
 struct bch_fs *bch2_dev_to_fs(dev_t dev)
 {
@@ -1150,15 +1149,11 @@ int bch2_fs_start(struct bch_fs *c)
 		cpu_to_le64(now);
 	rcu_read_unlock();
 
-	bch2_write_super(c);
+	/*
+	 * Dno't write superblock yet: recovery might have to downgrade
+	 */
 	mutex_unlock(&c->sb_lock);
 
-	ret = bch2_fs_resize_on_mount(c);
-	if (ret) {
-		up_write(&c->state_lock);
-		goto err;
-	}
-
 	rcu_read_lock();
 	for_each_online_member_rcu(c, ca)
 		if (ca->mi.state == BCH_MEMBER_STATE_rw)
@@ -1724,6 +1719,8 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 {
 	struct bch_member *m;
 	unsigned dev_idx = ca->dev_idx, data;
+	bool fast_device_removal = !bch2_request_incompat_feature(c,
+					bcachefs_metadata_version_fast_device_removal);
 	int ret;
 
 	down_write(&c->state_lock);
@@ -1742,11 +1739,24 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 
 	__bch2_dev_read_only(c, ca);
 
-	ret = bch2_dev_data_drop(c, ca->dev_idx, flags);
-	bch_err_msg(ca, ret, "bch2_dev_data_drop()");
+	ret = fast_device_removal
+		? bch2_dev_data_drop_by_backpointers(c, ca->dev_idx, flags)
+		: bch2_dev_data_drop(c, ca->dev_idx, flags);
 	if (ret)
 		goto err;
 
+	/* Check if device still has data */
+	struct bch_dev_usage usage = bch2_dev_usage_read(ca);
+	for (unsigned i = 0; i < BCH_DATA_NR; i++)
+		if (!data_type_is_empty(i) &&
+		    !data_type_is_hidden(i) &&
+		    usage.buckets[i]) {
+			bch_err(ca, "Remove failed: still has data (%s, %llu buckets)",
+				__bch2_data_types[i], usage.buckets[i]);
+			ret = -EBUSY;
+			goto err;
+		}
+
 	ret = bch2_dev_remove_alloc(c, ca);
 	bch_err_msg(ca, ret, "bch2_dev_remove_alloc()");
 	if (ret)
@@ -1810,7 +1820,11 @@ int bch2_dev_remove(struct bch_fs *c, struct bch_dev *ca, int flags)
 	 */
 	mutex_lock(&c->sb_lock);
 	m = bch2_members_v2_get_mut(c->disk_sb.sb, dev_idx);
-	memset(&m->uuid, 0, sizeof(m->uuid));
+
+	if (fast_device_removal)
+		m->uuid = BCH_SB_MEMBER_DELETED_UUID;
+	else
+		memset(&m->uuid, 0, sizeof(m->uuid));
 
 	bch2_write_super(c);
 
@@ -2120,7 +2134,7 @@ err:
 	return ret;
 }
 
-static int bch2_fs_resize_on_mount(struct bch_fs *c)
+int bch2_fs_resize_on_mount(struct bch_fs *c)
 {
 	for_each_online_member(c, ca, BCH_DEV_READ_REF_fs_resize_on_mount) {
 		u64 old_nbuckets = ca->mi.nbuckets;