linux/fs/bcachefs/errcode.h

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_ERRCODE_H
#define _BCACHEFS_ERRCODE_H
#define BCH_ERRCODES() \
x(ENOSPC, ENOSPC_disk_reservation) \
x(ENOSPC, ENOSPC_bucket_alloc) \
x(ENOSPC, ENOSPC_disk_label_add) \
x(ENOSPC, ENOSPC_stripe_create) \
x(ENOSPC, ENOSPC_stripe_reuse) \
x(ENOSPC, ENOSPC_inode_create) \
x(ENOSPC, ENOSPC_str_hash_create) \
x(ENOSPC, ENOSPC_snapshot_create) \
x(ENOSPC, ENOSPC_subvolume_create) \
x(ENOSPC, ENOSPC_sb) \
x(ENOSPC, ENOSPC_sb_journal) \
x(ENOSPC, ENOSPC_sb_quota) \
x(ENOSPC, ENOSPC_sb_replicas) \
x(ENOSPC, ENOSPC_sb_members) \
x(0, open_buckets_empty) \
x(0, freelist_empty) \
x(BCH_ERR_freelist_empty, no_buckets_found) \
x(0, insufficient_devices) \
x(0, transaction_restart) \
x(BCH_ERR_transaction_restart, transaction_restart_fault_inject) \
x(BCH_ERR_transaction_restart, transaction_restart_relock) \
x(BCH_ERR_transaction_restart, transaction_restart_relock_path) \
x(BCH_ERR_transaction_restart, transaction_restart_relock_path_intent) \
x(BCH_ERR_transaction_restart, transaction_restart_relock_after_fill) \
x(BCH_ERR_transaction_restart, transaction_restart_too_many_iters) \
x(BCH_ERR_transaction_restart, transaction_restart_lock_node_reused) \
x(BCH_ERR_transaction_restart, transaction_restart_fill_relock) \
x(BCH_ERR_transaction_restart, transaction_restart_fill_mem_alloc_fail)\
x(BCH_ERR_transaction_restart, transaction_restart_mem_realloced) \
x(BCH_ERR_transaction_restart, transaction_restart_in_traverse_all) \
x(BCH_ERR_transaction_restart, transaction_restart_would_deadlock) \
x(BCH_ERR_transaction_restart, transaction_restart_would_deadlock_write)\
bcachefs: Deadlock cycle detector We've outgrown our own deadlock avoidance strategy. The btree iterator API provides an interface where the user doesn't need to concern themselves with lock ordering - different btree iterators can be traversed in any order. Without special care, this will lead to deadlocks. Our previous strategy was to define a lock ordering internally, and whenever we attempt to take a lock and trylock() fails, we'd check if the current btree transaction is holding any locks that cause a lock ordering violation. If so, we'd issue a transaction restart, and then bch2_trans_begin() would re-traverse all previously used iterators, but in the correct order. That approach had some issues, though. - Sometimes we'd issue transaction restarts unnecessarily, when no deadlock would have actually occured. Lock ordering restarts have become our primary cause of transaction restarts, on some workloads totally 20% of actual transaction commits. - To avoid deadlock or livelock, we'd often have to take intent locks when we only wanted a read lock: with the lock ordering approach, it is actually illegal to hold _any_ read lock while blocking on an intent lock, and this has been causing us unnecessary lock contention. - It was getting fragile - the various lock ordering rules are not trivial, and we'd been seeing occasional livelock issues related to this machinery. So, since bcachefs is already a relational database masquerading as a filesystem, we're stealing the next traditional database technique and switching to a cycle detector for avoiding deadlocks. When we block taking a btree lock, after adding ourself to the waitlist but before sleeping, we do a DFS of btree transactions waiting on other btree transactions, starting with the current transaction and walking our held locks, and transactions blocking on our held locks. If we find a cycle, we emit a transaction restart. Occasionally (e.g. the btree split path) we can not allow the lock() operation to fail, so if necessary we'll tell another transaction that it has to fail. Result: trans_restart_would_deadlock events are reduced by a factor of 10 to 100, and we'll be able to delete a whole bunch of grotty, fragile code. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
2022-08-22 17:23:47 +00:00
x(BCH_ERR_transaction_restart, transaction_restart_deadlock_recursion_limit)\
x(BCH_ERR_transaction_restart, transaction_restart_upgrade) \
x(BCH_ERR_transaction_restart, transaction_restart_key_cache_upgrade) \
x(BCH_ERR_transaction_restart, transaction_restart_key_cache_fill) \
x(BCH_ERR_transaction_restart, transaction_restart_key_cache_raced) \
x(BCH_ERR_transaction_restart, transaction_restart_key_cache_realloced)\
x(BCH_ERR_transaction_restart, transaction_restart_journal_preres_get) \
x(BCH_ERR_transaction_restart, transaction_restart_split_race) \
x(BCH_ERR_transaction_restart, transaction_restart_nested) \
x(0, no_btree_node) \
x(BCH_ERR_no_btree_node, no_btree_node_relock) \
x(BCH_ERR_no_btree_node, no_btree_node_upgrade) \
x(BCH_ERR_no_btree_node, no_btree_node_drop) \
x(BCH_ERR_no_btree_node, no_btree_node_lock_root) \
x(BCH_ERR_no_btree_node, no_btree_node_up) \
x(BCH_ERR_no_btree_node, no_btree_node_down) \
x(BCH_ERR_no_btree_node, no_btree_node_init) \
x(BCH_ERR_no_btree_node, no_btree_node_cached) \
x(BCH_ERR_no_btree_node, no_btree_node_srcu_reset) \
x(0, btree_insert_fail) \
x(BCH_ERR_btree_insert_fail, btree_insert_btree_node_full) \
x(BCH_ERR_btree_insert_fail, btree_insert_need_mark_replicas) \
x(BCH_ERR_btree_insert_fail, btree_insert_need_journal_res) \
x(BCH_ERR_btree_insert_fail, btree_insert_need_journal_reclaim) \
x(0, lock_fail_root_changed) \
x(0, journal_reclaim_would_deadlock) \
x(0, fsck) \
x(BCH_ERR_fsck, fsck_fix) \
x(BCH_ERR_fsck, fsck_ignore) \
x(BCH_ERR_fsck, fsck_errors_not_fixed) \
x(BCH_ERR_fsck, fsck_repair_unimplemented) \
x(BCH_ERR_fsck, fsck_repair_impossible) \
x(0, need_snapshot_cleanup) \
x(0, need_topology_repair) \
x(EINVAL, device_state_not_allowed) \
x(EINVAL, member_info_missing) \
x(EINVAL, mismatched_block_size) \
x(EINVAL, block_size_too_small) \
x(EINVAL, bucket_size_too_small) \
x(EINVAL, device_size_too_small) \
x(EINVAL, device_not_a_member_of_filesystem) \
x(EINVAL, device_has_been_removed) \
x(EINVAL, device_already_online) \
x(EINVAL, insufficient_devices_to_start) \
x(EINVAL, invalid) \
x(BCH_ERR_invalid, invalid_sb) \
x(BCH_ERR_invalid_sb, invalid_sb_magic) \
x(BCH_ERR_invalid_sb, invalid_sb_version) \
x(BCH_ERR_invalid_sb, invalid_sb_features) \
x(BCH_ERR_invalid_sb, invalid_sb_too_big) \
x(BCH_ERR_invalid_sb, invalid_sb_csum_type) \
x(BCH_ERR_invalid_sb, invalid_sb_csum) \
x(BCH_ERR_invalid_sb, invalid_sb_block_size) \
x(BCH_ERR_invalid_sb, invalid_sb_uuid) \
x(BCH_ERR_invalid_sb, invalid_sb_too_many_members) \
x(BCH_ERR_invalid_sb, invalid_sb_dev_idx) \
x(BCH_ERR_invalid_sb, invalid_sb_time_precision) \
x(BCH_ERR_invalid_sb, invalid_sb_field_size) \
x(BCH_ERR_invalid_sb, invalid_sb_layout) \
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_type) \
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_nr_superblocks) \
x(BCH_ERR_invalid_sb_layout, invalid_sb_layout_superblocks_overlap) \
x(BCH_ERR_invalid_sb, invalid_sb_members_missing) \
x(BCH_ERR_invalid_sb, invalid_sb_members) \
x(BCH_ERR_invalid_sb, invalid_sb_disk_groups) \
x(BCH_ERR_invalid_sb, invalid_sb_replicas) \
x(BCH_ERR_invalid_sb, invalid_sb_journal) \
x(BCH_ERR_invalid_sb, invalid_sb_journal_seq_blacklist) \
x(BCH_ERR_invalid_sb, invalid_sb_crypt) \
x(BCH_ERR_invalid_sb, invalid_sb_clean) \
x(BCH_ERR_invalid_sb, invalid_sb_quota) \
x(BCH_ERR_invalid, invalid_bkey) \
enum bch_errcode {
BCH_ERR_START = 2048,
#define x(class, err) BCH_ERR_##err,
BCH_ERRCODES()
#undef x
BCH_ERR_MAX
};
const char *bch2_err_str(int);
bool __bch2_err_matches(int, int);
static inline bool _bch2_err_matches(int err, int class)
{
return err && __bch2_err_matches(err, class);
}
#define bch2_err_matches(_err, _class) \
({ \
BUILD_BUG_ON(!__builtin_constant_p(_class)); \
_bch2_err_matches(_err, _class); \
})
int __bch2_err_class(int);
static inline long bch2_err_class(long err)
{
return err < 0 ? __bch2_err_class(err) : err;
}
#endif /* _BCACHFES_ERRCODE_H */