path: root/fs/bcachefs/backpointers.c

// SPDX-License-Identifier: GPL-2.0
#include "bcachefs.h"
#include "bbpos.h"
#include "alloc_background.h"
#include "backpointers.h"
#include "bkey_buf.h"
#include "btree_cache.h"
#include "btree_update.h"
#include "btree_update_interior.h"
#include "btree_write_buffer.h"
#include "checksum.h"
#include "disk_accounting.h"
#include "error.h"

#include <linux/mm.h>

static bool extent_matches_bp(struct bch_fs *c,
			      enum btree_id btree_id, unsigned level,
			      struct bkey_s_c k,
			      struct bpos bucket,
			      struct bch_backpointer bp)
{
	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
	const union bch_extent_entry *entry;
	struct extent_ptr_decoded p;

	rcu_read_lock();
	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
		struct bpos bucket2;
		struct bch_backpointer bp2;

		if (p.ptr.cached)
			continue;

		struct bch_dev *ca = bch2_dev_rcu(c, p.ptr.dev);
		if (!ca)
			continue;

		bch2_extent_ptr_to_bp(c, ca, btree_id, level, k, p, entry, &bucket2, &bp2);
		if (bpos_eq(bucket, bucket2) &&
		    !memcmp(&bp, &bp2, sizeof(bp))) {
			rcu_read_unlock();
			return true;
		}
	}
	rcu_read_unlock();

	return false;
}

int bch2_backpointer_validate(struct bch_fs *c, struct bkey_s_c k,
			      enum bch_validate_flags flags)
{
	struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);

	rcu_read_lock();
	struct bch_dev *ca = bch2_dev_rcu_noerror(c, bp.k->p.inode);
	if (!ca) {
		/* these will be caught by fsck */
		rcu_read_unlock();
		return 0;
	}

	struct bpos bucket = bp_pos_to_bucket(ca, bp.k->p);
	struct bpos bp_pos = bucket_pos_to_bp_noerror(ca, bucket, bp.v->bucket_offset);
	rcu_read_unlock();
	int ret = 0;

	bkey_fsck_err_on((bp.v->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT) >= ca->mi.bucket_size ||
			 !bpos_eq(bp.k->p, bp_pos),
			 c, backpointer_bucket_offset_wrong,
			 "backpointer bucket_offset wrong");
fsck_err:
	return ret;
}

void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
{
	prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
	       bch2_btree_id_str(bp->btree_id),
	       bp->level,
	       (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
	       (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
	       bp->bucket_len);
	bch2_bpos_to_text(out, bp->pos);
}

void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
{
	rcu_read_lock();
	struct bch_dev *ca = bch2_dev_rcu_noerror(c, k.k->p.inode);
	if (ca) {
		struct bpos bucket = bp_pos_to_bucket(ca, k.k->p);
		rcu_read_unlock();
		prt_str(out, "bucket=");
		bch2_bpos_to_text(out, bucket);
		prt_str(out, " ");
	} else {
		rcu_read_unlock();
	}

	bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
}

void bch2_backpointer_swab(struct bkey_s k)
{
	struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);

	bp.v->bucket_offset	= swab40(bp.v->bucket_offset);
	bp.v->bucket_len	= swab32(bp.v->bucket_len);
	bch2_bpos_swab(&bp.v->pos);
}

static noinline int backpointer_mod_err(struct btree_trans *trans,
					struct bch_backpointer bp,
					struct bkey_s_c bp_k,
					struct bkey_s_c orig_k,
					bool insert)
{
	struct bch_fs *c = trans->c;
	struct printbuf buf = PRINTBUF;

	if (insert) {
		prt_printf(&buf, "existing backpointer found when inserting ");
		bch2_backpointer_to_text(&buf, &bp);
		prt_newline(&buf);
		printbuf_indent_add(&buf, 2);

		prt_printf(&buf, "found ");
		bch2_bkey_val_to_text(&buf, c, bp_k);
		prt_newline(&buf);

		prt_printf(&buf, "for ");
		bch2_bkey_val_to_text(&buf, c, orig_k);

		bch_err(c, "%s", buf.buf);
	} else if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {
		prt_printf(&buf, "backpointer not found when deleting\n");
		printbuf_indent_add(&buf, 2);

		prt_printf(&buf, "searching for ");
		bch2_backpointer_to_text(&buf, &bp);
		prt_newline(&buf);

		prt_printf(&