bcachefs: Reflink

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

1 files changed, 300 insertions, 0 deletions

diff --git a/fs/bcachefs/reflink.c b/fs/bcachefs/reflink.c
new file mode 100644
index 000000000000..dcca9c1d0f47
--- /dev/null
+++ b/fs/bcachefs/reflink.c
@@ -0,0 +1,300 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "bcachefs.h"
+#include "btree_update.h"
+#include "extents.h"
+#include "fs.h"
+#include "fs-io.h"
+#include "reflink.h"
+
+#include <linux/sched/signal.h>
+
+/* reflink pointers */
+
+const char *bch2_reflink_p_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
+
+	if (bkey_val_bytes(p.k) != sizeof(*p.v))
+		return "incorrect value size";
+
+	return NULL;
+}
+
+void bch2_reflink_p_to_text(struct printbuf *out, struct bch_fs *c,
+			    struct bkey_s_c k)
+{
+	struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
+
+	pr_buf(out, "idx %llu", le64_to_cpu(p.v->idx));
+}
+
+enum merge_result bch2_reflink_p_merge(struct bch_fs *c,
+				       struct bkey_s _l, struct bkey_s _r)
+{
+	struct bkey_s_reflink_p l = bkey_s_to_reflink_p(_l);
+	struct bkey_s_reflink_p r = bkey_s_to_reflink_p(_r);
+
+	if (le64_to_cpu(l.v->idx) + l.k->size != le64_to_cpu(r.v->idx))
+		return BCH_MERGE_NOMERGE;
+
+	if ((u64) l.k->size + r.k->size > KEY_SIZE_MAX) {
+		bch2_key_resize(l.k, KEY_SIZE_MAX);
+		__bch2_cut_front(l.k->p, _r);
+		return BCH_MERGE_PARTIAL;
+	}
+
+	bch2_key_resize(l.k, l.k->size + r.k->size);
+
+	return BCH_MERGE_MERGE;
+}
+
+/* indirect extents */
+
+const char *bch2_reflink_v_invalid(const struct bch_fs *c, struct bkey_s_c k)
+{
+	struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
+
+	if (bkey_val_bytes(r.k) < sizeof(*r.v))
+		return "incorrect value size";
+
+	return bch2_bkey_ptrs_invalid(c, k);
+}
+
+void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
+			    struct bkey_s_c k)
+{
+	struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
+
+	pr_buf(out, "refcount: %llu ", le64_to_cpu(r.v->refcount));
+
+	bch2_bkey_ptrs_to_text(out, c, k);
+}
+
+/*
+ * bch2_remap_range() depends on bch2_extent_update(), which depends on various
+ * things tied to the linux vfs for inode updates, for now:
+ */
+#ifndef NO_BCACHEFS_FS
+
+static int bch2_make_extent_indirect(struct btree_trans *trans,
+				     struct btree_iter *extent_iter,
+				     struct bkey_i_extent *e)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter *reflink_iter;
+	struct bkey_s_c k;
+	struct bkey_i_reflink_v *r_v;
+	struct bkey_i_reflink_p *r_p;
+	int ret;
+
+	for_each_btree_key(trans, reflink_iter, BTREE_ID_REFLINK,
+			   POS(0, c->reflink_hint),
+			   BTREE_ITER_INTENT|BTREE_ITER_SLOTS, k, ret) {
+		if (reflink_iter->pos.inode) {
+			bch2_btree_iter_set_pos(reflink_iter, POS_MIN);
+			continue;
+		}
+
+		if (bkey_deleted(k.k) && e->k.size <= k.k->size)
+			break;
+	}
+
+	if (ret)
+		goto err;
+
+	/* rewind iter to start of hole, if necessary: */
+	bch2_btree_iter_set_pos(reflink_iter, bkey_start_pos(k.k));
+
+	r_v = bch2_trans_kmalloc(trans, sizeof(*r_v) + bkey_val_bytes(&e->k));
+	ret = PTR_ERR_OR_ZERO(r_v);
+	if (ret)
+		goto err;
+
+	bkey_reflink_v_init(&r_v->k_i);
+	r_v->k.p	= reflink_iter->pos;
+	bch2_key_resize(&r_v->k, e->k.size);
+	r_v->k.version	= e->k.version;
+
+	set_bkey_val_u64s(&r_v->k, bkey_val_u64s(&r_v->k) +
+			  bkey_val_u64s(&e->k));
+	r_v->v.refcount	= 0;
+	memcpy(r_v->v.start, e->v.start, bkey_val_bytes(&e->k));
+
+	bch2_trans_update(trans, BTREE_INSERT_ENTRY(reflink_iter, &r_v->k_i));
+
+	r_p = bch2_trans_kmalloc(trans, sizeof(*r_p));
+	if (IS_ERR(r_p))
+		return PTR_ERR(r_p);
+
+	e->k.type = KEY_TYPE_reflink_p;
+	r_p = bkey_i_to_reflink_p(&e->k_i);
+	set_bkey_val_bytes(&r_p->k, sizeof(r_p->v));
+	r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
+
+	bch2_trans_update(trans, BTREE_INSERT_ENTRY(extent_iter, &r_p->k_i));
+err:
+	if (!IS_ERR(reflink_iter)) {
+		c->reflink_hint = reflink_iter->pos.offset;
+		bch2_trans_iter_put(trans, reflink_iter);
+	}
+
+	return ret;
+}
+
+static struct bkey_s_c get_next_src(struct btree_iter *iter, struct bpos end)
+{
+	struct bkey_s_c k = bch2_btree_iter_peek(iter);
+
+	while (1) {
+		if (bkey_err(k))
+			return k;
+
+		if (bkey_cmp(iter->pos, end) >= 0)
+			return bkey_s_c_null;
+
+		if (k.k->type == KEY_TYPE_extent ||
+		    k.k->type == KEY_TYPE_reflink_p)
+			return k;
+
+		k = bch2_btree_iter_next(iter);
+	}
+}
+
+s64 bch2_remap_range(struct bch_fs *c,
+		     struct bch_inode_info *dst_inode,
+		     struct bpos dst_start, struct bpos src_start,
+		     u64 remap_sectors, u64 new_i_size)
+{
+	struct btree_trans trans;
+	struct btree_iter *dst_iter, *src_iter;
+	struct bkey_s_c src_k;
+	BKEY_PADDED(k) new_dst, new_src;
+	struct bpos dst_end = dst_start, src_end = src_start;
+	struct bpos dst_want, src_want;
+	u64 src_done, dst_done;
+	int ret = 0;
+
+	if (!(c->sb.features & (1ULL << BCH_FEATURE_REFLINK))) {
+		mutex_lock(&c->sb_lock);
+		if (!(c->sb.features & (1ULL << BCH_FEATURE_REFLINK))) {
+			c->disk_sb.sb->features[0] |=
+				cpu_to_le64(1ULL << BCH_FEATURE_REFLINK);
+
+			bch2_write_super(c);
+		}
+		mutex_unlock(&c->sb_lock);
+	}
+
+	dst_end.offset += remap_sectors;
+	src_end.offset += remap_sectors;
+
+	bch2_trans_init(&trans, c, BTREE_ITER_MAX, 4096);
+
+	src_iter = __bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, src_start,
+					 BTREE_ITER_INTENT, 1);
+	dst_iter = __bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, dst_start,
+					 BTREE_ITER_INTENT, 2);
+
+	while (1) {
+		bch2_trans_begin_updates(&trans);
+		trans.mem_top = 0;
+
+		if (fatal_signal_pending(current)) {
+			ret = -EINTR;
+			goto err;
+		}
+
+		src_k = get_next_src(src_iter, src_end);
+		ret = bkey_err(src_k);
+		if (ret)
+			goto btree_err;
+
+		src_done = bpos_min(src_iter->pos, src_end).offset -
+			src_start.offset;
+		dst_want = POS(dst_start.inode, dst_start.offset + src_done);
+
+		if (bkey_cmp(dst_iter->pos, dst_want) < 0) {
+			ret = bch2_fpunch_at(&trans, dst_iter, dst_want,
+					     dst_inode, new_i_size);
+			if (ret)
+				goto btree_err;
+			continue;
+		}
+
+		BUG_ON(bkey_cmp(dst_iter->pos, dst_want));
+
+		if (!bkey_cmp(dst_iter->pos, dst_end))
+			break;
+
+		if (src_k.k->type == KEY_TYPE_extent) {
+			bkey_reassemble(&new_src.k, src_k);
+			src_k = bkey_i_to_s_c(&new_src.k);
+
+			bch2_cut_front(src_iter->pos,	&new_src.k);
+			bch2_cut_back(src_end,		&new_src.k.k);
+
+			ret = bch2_make_extent_indirect(&trans, src_iter,
+						bkey_i_to_extent(&new_src.k));
+			if (ret)
+				goto btree_err;
+
+			BUG_ON(src_k.k->type != KEY_TYPE_reflink_p);
+		}
+
+		if (src_k.k->type == KEY_TYPE_reflink_p) {
+			struct bkey_s_c_reflink_p src_p =
+				bkey_s_c_to_reflink_p(src_k);
+			struct bkey_i_reflink_p *dst_p =
+				bkey_reflink_p_init(&new_dst.k);
+
+			u64 offset = le64_to_cpu(src_p.v->idx) +
+				(src_iter->pos.offset -
+				 bkey_start_offset(src_k.k));
+
+			dst_p->v.idx = cpu_to_le64(offset);
+		} else {
+			BUG();
+		}
+
+		new_dst.k.k.p = dst_iter->pos;
+		bch2_key_resize(&new_dst.k.k,
+				min(src_k.k->p.offset - src_iter->pos.offset,
+				    dst_end.offset - dst_iter->pos.offset));
+
+		ret = bch2_extent_update(&trans, dst_inode, NULL, NULL,
+					 dst_iter, &new_dst.k,
+					 new_i_size, false, true, NULL);
+		if (ret)
+			goto btree_err;
+
+		dst_done = dst_iter->pos.offset - dst_start.offset;
+		src_want = POS(src_start.inode, src_start.offset + dst_done);
+		bch2_btree_iter_set_pos(src_iter, src_want);
+btree_err:
+		if (ret == -EINTR)
+			ret = 0;
+		if (ret)
+			goto err;
+	}
+
+	BUG_ON(bkey_cmp(dst_iter->pos, dst_end));
+err:
+	BUG_ON(bkey_cmp(dst_iter->pos, dst_end) > 0);
+
+	dst_done = dst_iter->pos.offset - dst_start.offset;
+	new_i_size = min(dst_iter->pos.offset << 9, new_i_size);
+
+	ret = bch2_trans_exit(&trans) ?: ret;
+
+	mutex_lock(&dst_inode->ei_update_lock);
+	if (dst_inode->v.i_size < new_i_size) {
+		i_size_write(&dst_inode->v, new_i_size);
+		ret = bch2_write_inode_size(c, dst_inode, new_i_size,
+					    ATTR_MTIME|ATTR_CTIME);
+	}
+	mutex_unlock(&dst_inode->ei_update_lock);
+
+	return dst_done ?: ret;
+}
+
+#endif /* NO_BCACHEFS_FS */