path: root/fs/bcachefs/subvolume.c

// SPDX-License-Identifier: GPL-2.0

#include "bcachefs.h"
#include "btree_key_cache.h"
#include "btree_update.h"
#include "errcode.h"
#include "error.h"
#include "fs.h"
#include "subvolume.h"

/* Snapshot tree: */

void bch2_snapshot_to_text(struct printbuf *out, struct bch_fs *c,
			   struct bkey_s_c k)
{
	struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(k);

	prt_printf(out, "is_subvol %llu deleted %llu parent %10u children %10u %10u subvol %u",
	       BCH_SNAPSHOT_SUBVOL(s.v),
	       BCH_SNAPSHOT_DELETED(s.v),
	       le32_to_cpu(s.v->parent),
	       le32_to_cpu(s.v->children[0]),
	       le32_to_cpu(s.v->children[1]),
	       le32_to_cpu(s.v->subvol));
}

int bch2_snapshot_invalid(const struct bch_fs *c, struct bkey_s_c k,
			  unsigned flags, struct printbuf *err)
{
	struct bkey_s_c_snapshot s;
	u32 i, id;

	if (bkey_gt(k.k->p, POS(0, U32_MAX)) ||
	    bkey_lt(k.k->p, POS(0, 1))) {
		prt_printf(err, "bad pos");
		return -BCH_ERR_invalid_bkey;
	}

	if (bkey_val_bytes(k.k) != sizeof(struct bch_snapshot)) {
		prt_printf(err, "bad val size (%zu != %zu)",
		       bkey_val_bytes(k.k), sizeof(struct bch_snapshot));
		return -BCH_ERR_invalid_bkey;
	}

	s = bkey_s_c_to_snapshot(k);

	id = le32_to_cpu(s.v->parent);
	if (id && id <= k.k->p.offset) {
		prt_printf(err, "bad parent node (%u <= %llu)",
		       id, k.k->p.offset);
		return -BCH_ERR_invalid_bkey;
	}

	if (le32_to_cpu(s.v->children[0]) < le32_to_cpu(s.v->children[1])) {
		prt_printf(err, "children not normalized");
		return -BCH_ERR_invalid_bkey;
	}

	if (s.v->children[0] &&
	    s.v->children[0] == s.v->children[1]) {
		prt_printf(err, "duplicate child nodes");
		return -BCH_ERR_invalid_bkey;
	}

	for (i = 0; i < 2; i++) {
		id = le32_to_cpu(s.v->children[i]);

		if (id >= k.k->p.offset) {
			prt_printf(err, "bad child node (%u >= %llu)",
			       id, k.k->p.offset);
			return -BCH_ERR_invalid_bkey;
		}
	}

	return 0;
}

int bch2_mark_snapshot(struct btree_trans *trans,
		       enum btree_id btree, unsigned level,
		       struct bkey_s_c old, struct bkey_s_c new,
		       unsigned flags)
{
	struct bch_fs *c = trans->c;
	struct snapshot_t *t;

	t = genradix_ptr_alloc(&c->snapshots,
			       U32_MAX - new.k->p.offset,
			       GFP_KERNEL);
	if (!t)
		return -BCH_ERR_ENOMEM_mark_snapshot;

	if (new.k->type == KEY_TYPE_snapshot) {
		struct bkey_s_c_snapshot s = bkey_s_c_to_snapshot(new);

		t->parent	= le32_to_cpu(s.v->parent);
		t->children[0]	= le32_to_cpu(s.v->children[0]);
		t->children[1]	= le32_to_cpu(s.v->children[1]);
		t->subvol	= BCH_SNAPSHOT_SUBVOL(s.v) ? le32_to_cpu(s.v->subvol) : 0;
	} else {
		t->parent	= 0;
		t->children[0]	= 0;
		t->children[1]	= 0;
		t->subvol	= 0;
	}

	return 0;
}

static int snapshot_lookup(struct btree_trans *trans, u32 id,
			   struct bch_snapshot *s)
{
	struct btree_iter iter;
	struct bkey_s_c k;
	int ret;

	bch2_trans_iter_init(trans, &iter, BTREE_ID_snapshots, POS(0, id),
			     BTREE_ITER_WITH_UPDATES);
	k = bch2_btree_iter_peek_slot(&iter);
	ret = bkey_err(k) ?: k.k->type == KEY_TYPE_snapshot ? 0 : -ENOENT;

	if (!ret)
		*s = *bkey_s_c_to_snapshot(k).v;

	bch2_trans_iter_exit(trans, &iter);
	return ret;
}

static int snapshot_live(struct btree_trans *trans, u32 id)
{
	struct bch_snapshot v;