// 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 "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; 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {		struct bpos bucket2;		struct bch_backpointer bp2; 		if (p.ptr.cached)			continue; 		bch2_extent_ptr_to_bp(c, btree_id, level, k, p,				      &bucket2, &bp2);		if (bpos_eq(bucket, bucket2) &&		    !memcmp(&bp, &bp2, sizeof(bp)))			return true;	} 	return false;} int bch2_backpointer_invalid(struct bch_fs *c, struct bkey_s_c k,			     enum bkey_invalid_flags flags,			     struct printbuf *err){	struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);	struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);	int ret = 0; 	bkey_fsck_err_on(!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset)),			 c, err,			 backpointer_pos_wrong,			 "backpointer at wrong pos");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){	if (bch2_dev_exists2(c, k.k->p.inode)) {		prt_str(out, "bucket=");		bch2_bpos_to_text(out, bp_pos_to_bucket(c, k.k->p));		prt_str(out, " ");	} 	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");		prt_newline(&buf);		printbuf_indent_add(&buf, 2); 		prt_printf(&buf, "searching for ");		bch2_backpointer_to_text(&buf, &bp);		prt_newline(&buf); 		prt_printf(&buf, "got ");		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);	} 	printbuf_exit(&buf); 	if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {		bch2_inconsistent_error(c);		return -EIO;	} else {		return 0;	}} int bch2_bucket_backpointer_mod_nowritebuffer(struct btree_trans *trans,				struct bpos bucket,				struct bch_backpointer bp,				struct bkey_s_c orig_k,				bool insert){	struct btree_iter bp_iter;	struct bkey_s_c k;	struct bkey_i_backpointer *bp_k;	int ret; 	bp_k = bch2_trans_kmalloc_nomemzero(trans, sizeof(struct bkey_i_backpointer));	ret = PTR_ERR_OR_ZERO(bp_k);	if (ret)		return ret; 	bkey_backpointer_init(&bp_k->k_i);	bp_k->k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset);	bp_k->v = bp; 	if (!insert) {		bp_k->k.type = KEY_TYPE_deleted;		set_bkey_val_u64s(&bp_k->k, 0);	} 	k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,			       bp_k->k.p,			       BTREE_ITER_INTENT|			       BTREE_ITER_SLOTS|			       BTREE_ITER_WITH_UPDATES);	ret = bkey_err(k);	if (ret)		goto err; 	if (insert	    ? k.k->type	    : (k.k->type != KEY_TYPE_backpointer ||	       memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp)))) {		ret = backpointer_mod_err(trans, bp, k, orig_k, insert);		if (ret)			goto err;	} 	ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);err:	bch2_trans_iter_exit(trans, &bp_iter);	return ret;} /* * Find the next backpointer >= *bp_offset: */int bch2_get_next_backpointer(struct btree_trans *trans,			      struct bpos bucket, int gen,			      struct bpos *bp_pos,			      struct bch_backpointer *bp,			      unsigned iter_flags){	struct bch_fs *c = trans->c;	struct bpos bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);	struct btree_iter alloc_iter = { NULL }, bp_iter = { NULL };	struct bkey_s_c k;	int ret = 0; 	if (bpos_ge(*bp_pos, bp_end_pos))		goto done; 	if (gen >= 0) {		k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,				       bucket, BTREE_ITER_CACHED|iter_flags);		ret = bkey_err(k);		if (ret)			goto out; 		if (k.k->type != KEY_TYPE_alloc_v4 ||		    bkey_s_c_to_alloc_v4(k).v->gen != gen)			goto done;	} 	*bp_pos = bpos_max(*bp_pos, bucket_pos_to_bp(c, bucket, 0)); 	for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,				     *bp_pos, iter_flags, k, ret) {		if (bpos_ge(k.k->p, bp_end_pos))			break; 		*bp_pos = k.k->p;		*bp = *bkey_s_c_to_backpointer(k).v;		goto out;	}done:	*bp_pos = SPOS_MAX;out:	bch2_trans_iter_exit(trans, &bp_iter);	bch2_trans_iter_exit(trans, &alloc_iter);	return ret;} static void backpointer_not_found(struct btree_trans *trans,				  struct bpos bp_pos,				  struct bch_backpointer bp,				  struct bkey_s_c k){	struct bch_fs *c = trans->c;	struct printbuf buf = PRINTBUF;	struct bpos bucket = bp_pos_to_bucket(c, bp_pos); 	/*	 * If we're using the btree write buffer, the backpointer we were	 * looking at may have already been deleted - failure to find what it	 * pointed to is not an error:	 */	if (likely(!bch2_backpointers_no_use_write_buffer))		return; 	prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",		   bp.level ? "btree node" : "extent");	prt_printf(&buf, "bucket: ");	bch2_bpos_to_text(&buf, bucket);	prt_printf(&buf, "\n  "); 	prt_printf(&buf, "backpointer pos: ");	bch2_bpos_to_text(&buf, bp_pos);	prt_printf(&buf, "\n  "); 	bch2_backpointer_to_text(&buf, &bp);	prt_printf(&buf, "\n  ");	bch2_bkey_val_to_text(&buf, c, k);	if (c->curr_recovery_pass >= BCH_RECOVERY_PASS_check_extents_to_backpointers)		bch_err_ratelimited(c, "%s", buf.buf);	else		bch2_trans_inconsistent(trans, "%s", buf.buf); 	printbuf_exit(&buf);} struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,					 struct btree_iter *iter,					 struct bpos bp_pos,					 struct bch_backpointer bp,					 unsigned iter_flags){	if (likely(!bp.level)) {		struct bch_fs *c = trans->c;		struct bpos bucket = bp_pos_to_bucket(c, bp_pos);		struct bkey_s_c k; 		bch2_trans_node_iter_init(trans, iter,					  bp.btree_id,					  bp.pos,					  0, 0,					  iter_flags);		k = bch2_btree_iter_peek_slot(iter);		if (bkey_err(k)) {			bch2_trans_iter_exit(trans, iter);			return k;		} 		if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))			return k; 		bch2_trans_iter_exit(trans, iter);		backpointer_not_found(trans, bp_pos, bp, k);		return bkey_s_c_null;	} else {		struct btree *b = bch2_backpointer_get_node(trans, iter, bp_pos, bp); 		if (IS_ERR_OR_NULL(b)) {			bch2_trans_iter_exit(trans, iter);			return IS_ERR(b) ? bkey_s_c_err(PTR_ERR(b)) : bkey_s_c_null;		}		return bkey_i_to_s_c(&b->key);	}} struct btree *bch2_backpointer_get_node(struct btree_trans *trans,					struct btree_iter *iter,					struct bpos bp_pos,					struct bch_backpointer bp){	struct bch_fs *c = trans->c;	struct bpos bucket = bp_pos_to_bucket(c, bp_pos);	struct btree *b; 	BUG_ON(!bp.level); 	bch2_trans_node_iter_init(trans, iter,				  bp.btree_id,				  bp.pos,				  0,				  bp.level - 1,				  0);	b = bch2_btree_iter_peek_node(iter);	if (IS_ERR_OR_NULL(b))		goto err; 	BUG_ON(b->c.level != bp.level - 1); 	if (extent_matches_bp(c, bp.btree_id, bp.level,			      bkey_i_to_s_c(&b->key),			      bucket, bp))		return b; 	if (btree_node_will_make_reachable(b)) {		b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);	} else {		backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));		b = NULL;	}err:	bch2_trans_iter_exit(trans, iter);	return b;} static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,					struct bkey_s_c k){	struct bch_fs *c = trans->c;	struct btree_iter alloc_iter = { NULL };	struct bkey_s_c alloc_k;	struct printbuf buf = PRINTBUF;	int ret = 0; 	if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,			backpointer_to_missing_device,			"backpointer for missing device:\n%s",			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {		ret = bch2_btree_delete_at(trans, bp_iter, 0);		goto out;	} 	alloc_k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,				     bp_pos_to_bucket(c, k.k->p), 0);	ret = bkey_err(alloc_k);	if (ret)		goto out; 	if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,			backpointer_to_missing_alloc,			"backpointer for nonexistent alloc key: %llu:%llu:0\n%s",			alloc_iter.pos.inode, alloc_iter.pos.offset,			(bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {		ret = bch2_btree_delete_at(trans, bp_iter, 0);		goto out;	}out:fsck_err:	bch2_trans_iter_exit(trans, &alloc_iter);	printbuf_exit(&buf);	return ret;} /* verify that every backpointer has a corresponding alloc key */int bch2_check_btree_backpointers(struct bch_fs *c){	int ret = bch2_trans_run(c,		for_each_btree_key_commit(trans, iter,			BTREE_ID_backpointers, POS_MIN, 0, k,			NULL, NULL, BCH_TRANS_COMMIT_no_enospc,		  bch2_check_btree_backpointer(trans, &iter, k)));	bch_err_fn(c, ret);	return ret;} static inline bool bkey_and_val_eq(struct bkey_s_c l, struct bkey_s_c r){	return bpos_eq(l.k->p, r.k->p) &&		bkey_bytes(l.k) == bkey_bytes(r.k) &&		!memcmp(l.v, r.v, bkey_val_bytes(l.k));} struct extents_to_bp_state {	struct bpos	bucket_start;	struct bpos	bucket_end;	struct bkey_buf last_flushed;}; static int check_bp_exists(struct btree_trans *trans,			   struct extents_to_bp_state *s,			   struct bpos bucket,			   struct bch_backpointer bp,			   struct bkey_s_c orig_k){	struct bch_fs *c = trans->c;	struct btree_iter bp_iter = { NULL };	struct printbuf buf = PRINTBUF;	struct bkey_s_c bp_k;	struct bkey_buf tmp;	int ret; 	bch2_bkey_buf_init(&tmp); 	if (bpos_lt(bucket, s->bucket_start) ||	    bpos_gt(bucket, s->bucket_end))		return 0; 	if (!bch2_dev_bucket_exists(c, bucket))		goto missing; 	bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,				  bucket_pos_to_bp(c, bucket, bp.bucket_offset),				  0);	ret = bkey_err(bp_k);	if (ret)		goto err; 	if (bp_k.k->type != KEY_TYPE_backpointer ||	    memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp))) {		bch2_bkey_buf_reassemble(&tmp, c, orig_k); 		if (!bkey_and_val_eq(orig_k, bkey_i_to_s_c(s->last_flushed.k))) {			if (bp.level) {				bch2_trans_unlock(trans);				bch2_btree_interior_updates_flush(c);			} 			ret = bch2_btree_write_buffer_flush_sync(trans);			if (ret)				goto err; 			bch2_bkey_buf_copy(&s->last_flushed, c, tmp.k);			ret = -BCH_ERR_transaction_restart_write_buffer_flush;			goto out;		}		goto missing;	}out:err:fsck_err:	bch2_trans_iter_exit(trans, &bp_iter);	bch2_bkey_buf_exit(&tmp, c);	printbuf_exit(&buf);	return ret;missing:	prt_printf(&buf, "missing backpointer for btree=%s l=%u ",	       bch2_btree_id_str(bp.btree_id), bp.level);	bch2_bkey_val_to_text(&buf, c, orig_k);	prt_printf(&buf, "\nbp pos ");	bch2_bpos_to_text(&buf, bp_iter.pos); 	if (c->opts.reconstruct_alloc ||	    fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf))		ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true); 	goto out;} static int check_extent_to_backpointers(struct btree_trans *trans,					struct extents_to_bp_state *s,					enum btree_id btree, unsigned level,					struct bkey_s_c k){	struct bch_fs *c = trans->c;	struct bkey_ptrs_c ptrs;	const union bch_extent_entry *entry;	struct extent_ptr_decoded p;	int ret; 	ptrs = bch2_bkey_ptrs_c(k);	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {

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