diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-04-04 14:36:32 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-04-04 14:36:32 -0700 |
commit | ec25bd8d981d910cdcc84914bf57e2cff9e7d63b (patch) | |
tree | 32139d7aca4bec9ca4388e6bac4c9f4390a9ceac /fs/bcachefs/backpointers.c | |
parent | c85af715cac0a951eea97393378e84bb49384734 (diff) | |
parent | 09d4c2acbf4c864fef0f520bbcba256c9a19102e (diff) |
Merge tag 'bcachefs-2024-04-03' of https://evilpiepirate.org/git/bcachefs
Pull bcachefs repair code from Kent Overstreet:
"A couple more small fixes, and new repair code.
We can now automatically recover from arbitrary corrupted interior
btree nodes by scanning, and we can reconstruct metadata as needed to
bring a filesystem back into a working, consistent, read-write state
and preserve access to whatevver wasn't corrupted.
Meaning - you can blow away all metadata except for extents and
dirents leaf nodes, and repair will reconstruct everything else and
give you your data, and under the correct paths. If inodes are missing
i_size will be slightly off and permissions/ownership/timestamps will
be gone, and we do still need the snapshots btree if snapshots were in
use - in the future we'll be able to guess the snapshot tree structure
in some situations.
IOW - aside from shaking out remaining bugs (fuzz testing is still
coming), repair code should be complete and if repair ever doesn't
work that's the highest priority bug that I want to know about
immediately.
This patchset was kindly tested by a user from India who accidentally
wiped one drive out of a three drive filesystem with no replication on
the family computer - it took a couple weeks but we got everything
important back"
* tag 'bcachefs-2024-04-03' of https://evilpiepirate.org/git/bcachefs:
bcachefs: reconstruct_inode()
bcachefs: Subvolume reconstruction
bcachefs: Check for extents that point to same space
bcachefs: Reconstruct missing snapshot nodes
bcachefs: Flag btrees with missing data
bcachefs: Topology repair now uses nodes found by scanning to fill holes
bcachefs: Repair pass for scanning for btree nodes
bcachefs: Don't skip fake btree roots in fsck
bcachefs: bch2_btree_root_alloc() -> bch2_btree_root_alloc_fake()
bcachefs: Etyzinger cleanups
bcachefs: bch2_shoot_down_journal_keys()
bcachefs: Clear recovery_passes_required as they complete without errors
bcachefs: ratelimit informational fsck errors
bcachefs: Check for bad needs_discard before doing discard
bcachefs: Improve bch2_btree_update_to_text()
mean_and_variance: Drop always failing tests
bcachefs: fix nocow lock deadlock
bcachefs: BCH_WATERMARK_interior_updates
bcachefs: Fix btree node reserve
Diffstat (limited to 'fs/bcachefs/backpointers.c')
-rw-r--r-- | fs/bcachefs/backpointers.c | 173 |
1 files changed, 166 insertions, 7 deletions
diff --git a/fs/bcachefs/backpointers.c b/fs/bcachefs/backpointers.c index 762c8ddfc5e7..114328acde72 100644 --- a/fs/bcachefs/backpointers.c +++ b/fs/bcachefs/backpointers.c @@ -8,6 +8,7 @@ #include "btree_update.h" #include "btree_update_interior.h" #include "btree_write_buffer.h" +#include "checksum.h" #include "error.h" #include <linux/mm.h> @@ -418,6 +419,84 @@ struct extents_to_bp_state { struct bkey_buf last_flushed; }; +static int drop_dev_and_update(struct btree_trans *trans, enum btree_id btree, + struct bkey_s_c extent, unsigned dev) +{ + struct bkey_i *n = bch2_bkey_make_mut_noupdate(trans, extent); + int ret = PTR_ERR_OR_ZERO(n); + if (ret) + return ret; + + bch2_bkey_drop_device(bkey_i_to_s(n), dev); + return bch2_btree_insert_trans(trans, btree, n, 0); +} + +static int check_extent_checksum(struct btree_trans *trans, + enum btree_id btree, struct bkey_s_c extent, + enum btree_id o_btree, struct bkey_s_c extent2, unsigned dev) +{ + struct bch_fs *c = trans->c; + struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(extent); + const union bch_extent_entry *entry; + struct extent_ptr_decoded p; + struct printbuf buf = PRINTBUF; + void *data_buf = NULL; + struct bio *bio = NULL; + size_t bytes; + int ret = 0; + + if (bkey_is_btree_ptr(extent.k)) + return false; + + bkey_for_each_ptr_decode(extent.k, ptrs, p, entry) + if (p.ptr.dev == dev) + goto found; + BUG(); +found: + if (!p.crc.csum_type) + return false; + + bytes = p.crc.compressed_size << 9; + + struct bch_dev *ca = bch_dev_bkey_exists(c, dev); + if (!bch2_dev_get_ioref(ca, READ)) + return false; + + data_buf = kvmalloc(bytes, GFP_KERNEL); + if (!data_buf) { + ret = -ENOMEM; + goto err; + } + + bio = bio_alloc(ca->disk_sb.bdev, 1, REQ_OP_READ, GFP_KERNEL); + bio->bi_iter.bi_sector = p.ptr.offset; + bch2_bio_map(bio, data_buf, bytes); + ret = submit_bio_wait(bio); + if (ret) + goto err; + + prt_str(&buf, "extents pointing to same space, but first extent checksum bad:"); + prt_printf(&buf, "\n %s ", bch2_btree_id_str(btree)); + bch2_bkey_val_to_text(&buf, c, extent); + prt_printf(&buf, "\n %s ", bch2_btree_id_str(o_btree)); + bch2_bkey_val_to_text(&buf, c, extent2); + + struct nonce nonce = extent_nonce(extent.k->version, p.crc); + struct bch_csum csum = bch2_checksum(c, p.crc.csum_type, nonce, data_buf, bytes); + if (fsck_err_on(bch2_crc_cmp(csum, p.crc.csum), + c, dup_backpointer_to_bad_csum_extent, + "%s", buf.buf)) + ret = drop_dev_and_update(trans, btree, extent, dev) ?: 1; +fsck_err: +err: + if (bio) + bio_put(bio); + kvfree(data_buf); + percpu_ref_put(&ca->io_ref); + printbuf_exit(&buf); + return ret; +} + static int check_bp_exists(struct btree_trans *trans, struct extents_to_bp_state *s, struct bpos bucket, @@ -425,7 +504,8 @@ static int check_bp_exists(struct btree_trans *trans, struct bkey_s_c orig_k) { struct bch_fs *c = trans->c; - struct btree_iter bp_iter = { NULL }; + struct btree_iter bp_iter = {}; + struct btree_iter other_extent_iter = {}; struct printbuf buf = PRINTBUF; struct bkey_s_c bp_k; struct bkey_buf tmp; @@ -433,13 +513,19 @@ static int check_bp_exists(struct btree_trans *trans, bch2_bkey_buf_init(&tmp); + if (!bch2_dev_bucket_exists(c, bucket)) { + prt_str(&buf, "extent for nonexistent device:bucket "); + bch2_bpos_to_text(&buf, bucket); + prt_str(&buf, "\n "); + bch2_bkey_val_to_text(&buf, c, orig_k); + bch_err(c, "%s", buf.buf); + return -BCH_ERR_fsck_repair_unimplemented; + } + 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); @@ -465,21 +551,94 @@ static int check_bp_exists(struct btree_trans *trans, ret = -BCH_ERR_transaction_restart_write_buffer_flush; goto out; } - goto missing; + + goto check_existing_bp; } out: err: fsck_err: + bch2_trans_iter_exit(trans, &other_extent_iter); bch2_trans_iter_exit(trans, &bp_iter); bch2_bkey_buf_exit(&tmp, c); printbuf_exit(&buf); return ret; +check_existing_bp: + /* Do we have a backpointer for a different extent? */ + if (bp_k.k->type != KEY_TYPE_backpointer) + goto missing; + + struct bch_backpointer other_bp = *bkey_s_c_to_backpointer(bp_k).v; + + struct bkey_s_c other_extent = + bch2_backpointer_get_key(trans, &other_extent_iter, bp_k.k->p, other_bp, 0); + ret = bkey_err(other_extent); + if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node) + ret = 0; + if (ret) + goto err; + + if (!other_extent.k) + goto missing; + + if (bch2_extents_match(orig_k, other_extent)) { + printbuf_reset(&buf); + prt_printf(&buf, "duplicate versions of same extent, deleting smaller\n "); + bch2_bkey_val_to_text(&buf, c, orig_k); + prt_str(&buf, "\n "); + bch2_bkey_val_to_text(&buf, c, other_extent); + bch_err(c, "%s", buf.buf); + + if (other_extent.k->size <= orig_k.k->size) { + ret = drop_dev_and_update(trans, other_bp.btree_id, other_extent, bucket.inode); + if (ret) + goto err; + goto out; + } else { + ret = drop_dev_and_update(trans, bp.btree_id, orig_k, bucket.inode); + if (ret) + goto err; + goto missing; + } + } + + ret = check_extent_checksum(trans, other_bp.btree_id, other_extent, bp.btree_id, orig_k, bucket.inode); + if (ret < 0) + goto err; + if (ret) { + ret = 0; + goto missing; + } + + ret = check_extent_checksum(trans, bp.btree_id, orig_k, other_bp.btree_id, other_extent, bucket.inode); + if (ret < 0) + goto err; + if (ret) { + ret = 0; + goto out; + } + + printbuf_reset(&buf); + prt_printf(&buf, "duplicate extents pointing to same space on dev %llu\n ", bucket.inode); + bch2_bkey_val_to_text(&buf, c, orig_k); + prt_str(&buf, "\n "); + bch2_bkey_val_to_text(&buf, c, other_extent); + bch_err(c, "%s", buf.buf); + ret = -BCH_ERR_fsck_repair_unimplemented; + goto err; missing: + printbuf_reset(&buf); 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); + prt_printf(&buf, "\n got: "); + bch2_bkey_val_to_text(&buf, c, bp_k); + + struct bkey_i_backpointer n_bp_k; + bkey_backpointer_init(&n_bp_k.k_i); + n_bp_k.k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset); + n_bp_k.v = bp; + prt_printf(&buf, "\n want: "); + bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&n_bp_k.k_i)); if (fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf)) ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true); |