bcachefs: Check for extents that point to same space
In backpointer repair, if we get a missing backpointer - but there's already a backpointer that points to an existing extent - we've got multiple extents that point to the same space and need to decide which to keep. Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet
parent
a292be3b68
commit
4c02e63dad
@ -8,6 +8,7 @@
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#include "btree_update.h"
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#include "btree_update_interior.h"
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#include "btree_write_buffer.h"
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#include "checksum.h"
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#include "error.h"
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#include <linux/mm.h>
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@ -418,6 +419,84 @@ struct extents_to_bp_state {
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struct bkey_buf last_flushed;
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};
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static int drop_dev_and_update(struct btree_trans *trans, enum btree_id btree,
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struct bkey_s_c extent, unsigned dev)
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{
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struct bkey_i *n = bch2_bkey_make_mut_noupdate(trans, extent);
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int ret = PTR_ERR_OR_ZERO(n);
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if (ret)
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return ret;
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bch2_bkey_drop_device(bkey_i_to_s(n), dev);
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return bch2_btree_insert_trans(trans, btree, n, 0);
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}
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static int check_extent_checksum(struct btree_trans *trans,
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enum btree_id btree, struct bkey_s_c extent,
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enum btree_id o_btree, struct bkey_s_c extent2, unsigned dev)
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{
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struct bch_fs *c = trans->c;
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struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(extent);
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const union bch_extent_entry *entry;
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struct extent_ptr_decoded p;
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struct printbuf buf = PRINTBUF;
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void *data_buf = NULL;
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struct bio *bio = NULL;
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size_t bytes;
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int ret = 0;
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if (bkey_is_btree_ptr(extent.k))
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return false;
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bkey_for_each_ptr_decode(extent.k, ptrs, p, entry)
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if (p.ptr.dev == dev)
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goto found;
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BUG();
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found:
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if (!p.crc.csum_type)
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return false;
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bytes = p.crc.compressed_size << 9;
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struct bch_dev *ca = bch_dev_bkey_exists(c, dev);
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if (!bch2_dev_get_ioref(ca, READ))
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return false;
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data_buf = kvmalloc(bytes, GFP_KERNEL);
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if (!data_buf) {
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ret = -ENOMEM;
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goto err;
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}
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bio = bio_alloc(ca->disk_sb.bdev, 1, REQ_OP_READ, GFP_KERNEL);
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bio->bi_iter.bi_sector = p.ptr.offset;
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bch2_bio_map(bio, data_buf, bytes);
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ret = submit_bio_wait(bio);
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if (ret)
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goto err;
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prt_str(&buf, "extents pointing to same space, but first extent checksum bad:");
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prt_printf(&buf, "\n %s ", bch2_btree_id_str(btree));
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bch2_bkey_val_to_text(&buf, c, extent);
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prt_printf(&buf, "\n %s ", bch2_btree_id_str(o_btree));
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bch2_bkey_val_to_text(&buf, c, extent2);
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struct nonce nonce = extent_nonce(extent.k->version, p.crc);
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struct bch_csum csum = bch2_checksum(c, p.crc.csum_type, nonce, data_buf, bytes);
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if (fsck_err_on(bch2_crc_cmp(csum, p.crc.csum),
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c, dup_backpointer_to_bad_csum_extent,
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"%s", buf.buf))
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ret = drop_dev_and_update(trans, btree, extent, dev) ?: 1;
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fsck_err:
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err:
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if (bio)
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bio_put(bio);
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kvfree(data_buf);
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percpu_ref_put(&ca->io_ref);
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printbuf_exit(&buf);
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return ret;
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}
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static int check_bp_exists(struct btree_trans *trans,
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struct extents_to_bp_state *s,
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struct bpos bucket,
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@ -425,7 +504,8 @@ static int check_bp_exists(struct btree_trans *trans,
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struct bkey_s_c orig_k)
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{
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struct bch_fs *c = trans->c;
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struct btree_iter bp_iter = { NULL };
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struct btree_iter bp_iter = {};
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struct btree_iter other_extent_iter = {};
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struct printbuf buf = PRINTBUF;
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struct bkey_s_c bp_k;
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struct bkey_buf tmp;
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@ -433,13 +513,19 @@ static int check_bp_exists(struct btree_trans *trans,
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bch2_bkey_buf_init(&tmp);
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if (!bch2_dev_bucket_exists(c, bucket)) {
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prt_str(&buf, "extent for nonexistent device:bucket ");
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bch2_bpos_to_text(&buf, bucket);
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prt_str(&buf, "\n ");
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bch2_bkey_val_to_text(&buf, c, orig_k);
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bch_err(c, "%s", buf.buf);
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return -BCH_ERR_fsck_repair_unimplemented;
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}
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if (bpos_lt(bucket, s->bucket_start) ||
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bpos_gt(bucket, s->bucket_end))
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return 0;
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if (!bch2_dev_bucket_exists(c, bucket))
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goto missing;
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bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
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bucket_pos_to_bp(c, bucket, bp.bucket_offset),
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0);
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@ -465,21 +551,94 @@ static int check_bp_exists(struct btree_trans *trans,
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ret = -BCH_ERR_transaction_restart_write_buffer_flush;
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goto out;
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}
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goto missing;
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goto check_existing_bp;
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}
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out:
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err:
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fsck_err:
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bch2_trans_iter_exit(trans, &other_extent_iter);
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bch2_trans_iter_exit(trans, &bp_iter);
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bch2_bkey_buf_exit(&tmp, c);
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printbuf_exit(&buf);
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return ret;
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check_existing_bp:
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/* Do we have a backpointer for a different extent? */
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if (bp_k.k->type != KEY_TYPE_backpointer)
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goto missing;
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struct bch_backpointer other_bp = *bkey_s_c_to_backpointer(bp_k).v;
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struct bkey_s_c other_extent =
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bch2_backpointer_get_key(trans, &other_extent_iter, bp_k.k->p, other_bp, 0);
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ret = bkey_err(other_extent);
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if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
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ret = 0;
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if (ret)
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goto err;
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if (!other_extent.k)
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goto missing;
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if (bch2_extents_match(orig_k, other_extent)) {
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printbuf_reset(&buf);
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prt_printf(&buf, "duplicate versions of same extent, deleting smaller\n ");
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bch2_bkey_val_to_text(&buf, c, orig_k);
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prt_str(&buf, "\n ");
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bch2_bkey_val_to_text(&buf, c, other_extent);
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bch_err(c, "%s", buf.buf);
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if (other_extent.k->size <= orig_k.k->size) {
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ret = drop_dev_and_update(trans, other_bp.btree_id, other_extent, bucket.inode);
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if (ret)
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goto err;
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goto out;
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} else {
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ret = drop_dev_and_update(trans, bp.btree_id, orig_k, bucket.inode);
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if (ret)
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goto err;
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goto missing;
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}
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}
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ret = check_extent_checksum(trans, other_bp.btree_id, other_extent, bp.btree_id, orig_k, bucket.inode);
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if (ret < 0)
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goto err;
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if (ret) {
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ret = 0;
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goto missing;
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}
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ret = check_extent_checksum(trans, bp.btree_id, orig_k, other_bp.btree_id, other_extent, bucket.inode);
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if (ret < 0)
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goto err;
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if (ret) {
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ret = 0;
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goto out;
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}
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printbuf_reset(&buf);
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prt_printf(&buf, "duplicate extents pointing to same space on dev %llu\n ", bucket.inode);
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bch2_bkey_val_to_text(&buf, c, orig_k);
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prt_str(&buf, "\n ");
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bch2_bkey_val_to_text(&buf, c, other_extent);
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bch_err(c, "%s", buf.buf);
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ret = -BCH_ERR_fsck_repair_unimplemented;
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goto err;
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missing:
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printbuf_reset(&buf);
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prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
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bch2_btree_id_str(bp.btree_id), bp.level);
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bch2_bkey_val_to_text(&buf, c, orig_k);
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prt_printf(&buf, "\nbp pos ");
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bch2_bpos_to_text(&buf, bp_iter.pos);
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prt_printf(&buf, "\n got: ");
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bch2_bkey_val_to_text(&buf, c, bp_k);
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struct bkey_i_backpointer n_bp_k;
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bkey_backpointer_init(&n_bp_k.k_i);
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n_bp_k.k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset);
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n_bp_k.v = bp;
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prt_printf(&buf, "\n want: ");
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bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&n_bp_k.k_i));
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if (fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf))
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ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true);
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@ -269,7 +269,8 @@
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x(btree_node_topology_empty_interior_node, 261) \
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x(btree_ptr_v2_min_key_bad, 262) \
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x(btree_root_unreadable_and_scan_found_nothing, 263) \
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x(snapshot_node_missing, 264)
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x(snapshot_node_missing, 264) \
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x(dup_backpointer_to_bad_csum_extent, 265)
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enum bch_sb_error_id {
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#define x(t, n) BCH_FSCK_ERR_##t = n,
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