From cb8336ca42e493a76b3cc05b76a51a2eed26cdaa Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 11 Mar 2025 10:02:40 -0400 Subject: [PATCH] bcachefs: Data move can read from poisoned extents Now, if an extent is poisoned we can move it even if there was a checksum error. We'll have to give it a new checksum, but the poison bit means that userspace will still see the appropriate error when they try to read it. Signed-off-by: Kent Overstreet --- fs/bcachefs/extents.c | 6 +----- fs/bcachefs/io_read.c | 4 ++++ fs/bcachefs/move.c | 26 ++++++++++++++++++++------ 3 files changed, 25 insertions(+), 11 deletions(-) diff --git a/fs/bcachefs/extents.c b/fs/bcachefs/extents.c index e597fb9c9823..a369f978ffe6 100644 --- a/fs/bcachefs/extents.c +++ b/fs/bcachefs/extents.c @@ -136,12 +136,8 @@ int bch2_bkey_pick_read_device(struct bch_fs *c, struct bkey_s_c k, if (k.k->type == KEY_TYPE_error) return -BCH_ERR_key_type_error; - struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k); - - if (bch2_bkey_extent_ptrs_flags(ptrs) & BIT_ULL(BCH_EXTENT_FLAG_poisoned)) - return -BCH_ERR_extent_poisoned; - rcu_read_lock(); + struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k); const union bch_extent_entry *entry; struct extent_ptr_decoded p; u64 pick_latency; diff --git a/fs/bcachefs/io_read.c b/fs/bcachefs/io_read.c index 3f111f918345..751a9679d7e5 100644 --- a/fs/bcachefs/io_read.c +++ b/fs/bcachefs/io_read.c @@ -1053,6 +1053,10 @@ int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig, bvec_iter_sectors(iter)); goto out_read_done; } + + if ((bch2_bkey_extent_flags(k) & BIT_ULL(BCH_EXTENT_FLAG_poisoned)) && + !orig->data_update) + return -BCH_ERR_extent_poisoned; retry_pick: ret = bch2_bkey_pick_read_device(c, k, failed, &pick, dev); diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c index dfdbb9259985..fe2fa665150b 100644 --- a/fs/bcachefs/move.c +++ b/fs/bcachefs/move.c @@ -126,26 +126,40 @@ static void move_write_done(struct bch_write_op *op) static void move_write(struct moving_io *io) { + struct bch_fs *c = io->write.op.c; struct moving_context *ctxt = io->write.ctxt; + struct bch_read_bio *rbio = &io->write.rbio; if (ctxt->stats) { - if (io->write.rbio.bio.bi_status) + if (rbio->bio.bi_status) atomic64_add(io->write.rbio.bvec_iter.bi_size >> 9, &ctxt->stats->sectors_error_uncorrected); - else if (io->write.rbio.saw_error) + else if (rbio->saw_error) atomic64_add(io->write.rbio.bvec_iter.bi_size >> 9, &ctxt->stats->sectors_error_corrected); } - if (unlikely(io->write.rbio.ret || - io->write.rbio.bio.bi_status || - io->write.data_opts.scrub)) { + /* + * If the extent has been bitrotted, we're going to have to give it a + * new checksum in order to move it - but the poison bit will ensure + * that userspace still gets the appropriate error. + */ + if (unlikely(rbio->ret == -BCH_ERR_data_read_csum_err && + (bch2_bkey_extent_flags(bkey_i_to_s_c(io->write.k.k)) & BIT_ULL(BCH_EXTENT_FLAG_poisoned)))) { + struct bch_extent_crc_unpacked crc = rbio->pick.crc; + struct nonce nonce = extent_nonce(rbio->version, crc); + + rbio->pick.crc.csum = bch2_checksum_bio(c, rbio->pick.crc.csum_type, + nonce, &rbio->bio); + rbio->ret = 0; + } + + if (unlikely(rbio->ret || io->write.data_opts.scrub)) { move_free(io); return; } if (trace_io_move_write_enabled()) { - struct bch_fs *c = io->write.op.c; struct printbuf buf = PRINTBUF; bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(io->write.k.k)); -- 2.50.1