bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

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

1 files changed, 178 insertions, 0 deletions

diff --git a/fs/bcachefs/migrate.c b/fs/bcachefs/migrate.c
new file mode 100644
index 000000000000..8f618dc5160d
--- /dev/null
+++ b/fs/bcachefs/migrate.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Code for moving data off a device.
+ */
+
+#include "bcachefs.h"
+#include "btree_update.h"
+#include "buckets.h"
+#include "extents.h"
+#include "io.h"
+#include "journal.h"
+#include "keylist.h"
+#include "migrate.h"
+#include "move.h"
+#include "replicas.h"
+#include "super-io.h"
+
+static int drop_dev_ptrs(struct bch_fs *c, struct bkey_s_extent e,
+			 unsigned dev_idx, int flags, bool metadata)
+{
+	unsigned replicas = metadata ? c->opts.metadata_replicas : c->opts.data_replicas;
+	unsigned lost = metadata ? BCH_FORCE_IF_METADATA_LOST : BCH_FORCE_IF_DATA_LOST;
+	unsigned degraded = metadata ? BCH_FORCE_IF_METADATA_DEGRADED : BCH_FORCE_IF_DATA_DEGRADED;
+	unsigned nr_good;
+
+	bch2_extent_drop_device(e, dev_idx);
+
+	nr_good = bch2_extent_durability(c, e.c);
+	if ((!nr_good && !(flags & lost)) ||
+	    (nr_good < replicas && !(flags & degraded)))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int bch2_dev_usrdata_drop(struct bch_fs *c, unsigned dev_idx, int flags)
+{
+	struct bkey_s_c k;
+	struct bkey_s_extent e;
+	BKEY_PADDED(key) tmp;
+	struct btree_iter iter;
+	int ret = 0;
+
+	mutex_lock(&c->replicas_gc_lock);
+	bch2_replicas_gc_start(c, (1 << BCH_DATA_USER)|(1 << BCH_DATA_CACHED));
+
+	bch2_btree_iter_init(&iter, c, BTREE_ID_EXTENTS,
+			     POS_MIN, BTREE_ITER_PREFETCH);
+
+	while ((k = bch2_btree_iter_peek(&iter)).k &&
+	       !(ret = btree_iter_err(k))) {
+		if (!bkey_extent_is_data(k.k) ||
+		    !bch2_extent_has_device(bkey_s_c_to_extent(k), dev_idx)) {
+			ret = bch2_mark_bkey_replicas(c, BCH_DATA_USER, k);
+			if (ret)
+				break;
+			bch2_btree_iter_next(&iter);
+			continue;
+		}
+
+		bkey_reassemble(&tmp.key, k);
+		e = bkey_i_to_s_extent(&tmp.key);
+
+		ret = drop_dev_ptrs(c, e, dev_idx, flags, false);
+		if (ret)
+			break;
+
+		/*
+		 * If the new extent no longer has any pointers, bch2_extent_normalize()
+		 * will do the appropriate thing with it (turning it into a
+		 * KEY_TYPE_ERROR key, or just a discard if it was a cached extent)
+		 */
+		bch2_extent_normalize(c, e.s);
+
+		ret = bch2_mark_bkey_replicas(c, BCH_DATA_USER,
+					      bkey_i_to_s_c(&tmp.key));
+		if (ret)
+			break;
+
+		iter.pos = bkey_start_pos(&tmp.key.k);
+
+		ret = bch2_btree_insert_at(c, NULL, NULL, NULL,
+					   BTREE_INSERT_ATOMIC|
+					   BTREE_INSERT_NOFAIL,
+					   BTREE_INSERT_ENTRY(&iter, &tmp.key));
+
+		/*
+		 * don't want to leave ret == -EINTR, since if we raced and
+		 * something else overwrote the key we could spuriously return
+		 * -EINTR below:
+		 */
+		if (ret == -EINTR)
+			ret = 0;
+		if (ret)
+			break;
+	}
+
+	bch2_btree_iter_unlock(&iter);
+
+	bch2_replicas_gc_end(c, ret);
+	mutex_unlock(&c->replicas_gc_lock);
+
+	return ret;
+}
+
+static int bch2_dev_metadata_drop(struct bch_fs *c, unsigned dev_idx, int flags)
+{
+	struct btree_iter iter;
+	struct closure cl;
+	struct btree *b;
+	unsigned id;
+	int ret;
+
+	/* don't handle this yet: */
+	if (flags & BCH_FORCE_IF_METADATA_LOST)
+		return -EINVAL;
+
+	closure_init_stack(&cl);
+
+	mutex_lock(&c->replicas_gc_lock);
+	bch2_replicas_gc_start(c, 1 << BCH_DATA_BTREE);
+
+	for (id = 0; id < BTREE_ID_NR; id++) {
+		for_each_btree_node(&iter, c, id, POS_MIN, BTREE_ITER_PREFETCH, b) {
+			__BKEY_PADDED(k, BKEY_BTREE_PTR_VAL_U64s_MAX) tmp;
+			struct bkey_i_extent *new_key;
+retry:
+			if (!bch2_extent_has_device(bkey_i_to_s_c_extent(&b->key),
+						    dev_idx)) {
+				/*
+				 * we might have found a btree node key we
+				 * needed to update, and then tried to update it
+				 * but got -EINTR after upgrading the iter, but
+				 * then raced and the node is now gone:
+				 */
+				bch2_btree_iter_downgrade(&iter);
+
+				ret = bch2_mark_bkey_replicas(c, BCH_DATA_BTREE,
+							      bkey_i_to_s_c(&b->key));
+				if (ret)
+					goto err;
+			} else {
+				bkey_copy(&tmp.k, &b->key);
+				new_key = bkey_i_to_extent(&tmp.k);
+
+				ret = drop_dev_ptrs(c, extent_i_to_s(new_key),
+						    dev_idx, flags, true);
+				if (ret)
+					goto err;
+
+				ret = bch2_btree_node_update_key(c, &iter, b, new_key);
+				if (ret == -EINTR) {
+					b = bch2_btree_iter_peek_node(&iter);
+					goto retry;
+				}
+				if (ret)
+					goto err;
+			}
+		}
+		bch2_btree_iter_unlock(&iter);
+	}
+
+	ret = 0;
+out:
+	ret = bch2_replicas_gc_end(c, ret);
+	mutex_unlock(&c->replicas_gc_lock);
+
+	return ret;
+err:
+	bch2_btree_iter_unlock(&iter);
+	goto out;
+}
+
+int bch2_dev_data_drop(struct bch_fs *c, unsigned dev_idx, int flags)
+{
+	return bch2_dev_usrdata_drop(c, dev_idx, flags) ?:
+		bch2_dev_metadata_drop(c, dev_idx, flags);
+}