X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libbcachefs%2Fjournal.h;h=4544ce24bb8a654e62be91c5d7e0242e51893c1c;hb=06ff8b55b70fda44d91b31b5511fafd1680a8934;hp=88a9bd12447d803a11f91656a87da543c0d15024;hpb=63065c01285601afbe2457e92729efc11581e37d;p=bcachefs-tools-debian diff --git a/libbcachefs/journal.h b/libbcachefs/journal.h deleted file mode 100644 index 88a9bd1..0000000 --- a/libbcachefs/journal.h +++ /dev/null @@ -1,398 +0,0 @@ -#ifndef _BCACHE_JOURNAL_H -#define _BCACHE_JOURNAL_H - -/* - * THE JOURNAL: - * - * The primary purpose of the journal is to log updates (insertions) to the - * b-tree, to avoid having to do synchronous updates to the b-tree on disk. - * - * Without the journal, the b-tree is always internally consistent on - * disk - and in fact, in the earliest incarnations bcache didn't have a journal - * but did handle unclean shutdowns by doing all index updates synchronously - * (with coalescing). - * - * Updates to interior nodes still happen synchronously and without the journal - * (for simplicity) - this may change eventually but updates to interior nodes - * are rare enough it's not a huge priority. - * - * This means the journal is relatively separate from the b-tree; it consists of - * just a list of keys and journal replay consists of just redoing those - * insertions in same order that they appear in the journal. - * - * PERSISTENCE: - * - * For synchronous updates (where we're waiting on the index update to hit - * disk), the journal entry will be written out immediately (or as soon as - * possible, if the write for the previous journal entry was still in flight). - * - * Synchronous updates are specified by passing a closure (@flush_cl) to - * bch2_btree_insert() or bch_btree_insert_node(), which then pass that parameter - * down to the journalling code. That closure will will wait on the journal - * write to complete (via closure_wait()). - * - * If the index update wasn't synchronous, the journal entry will be - * written out after 10 ms have elapsed, by default (the delay_ms field - * in struct journal). - * - * JOURNAL ENTRIES: - * - * A journal entry is variable size (struct jset), it's got a fixed length - * header and then a variable number of struct jset_entry entries. - * - * Journal entries are identified by monotonically increasing 64 bit sequence - * numbers - jset->seq; other places in the code refer to this sequence number. - * - * A jset_entry entry contains one or more bkeys (which is what gets inserted - * into the b-tree). We need a container to indicate which b-tree the key is - * for; also, the roots of the various b-trees are stored in jset_entry entries - * (one for each b-tree) - this lets us add new b-tree types without changing - * the on disk format. - * - * We also keep some things in the journal header that are logically part of the - * superblock - all the things that are frequently updated. This is for future - * bcache on raw flash support; the superblock (which will become another - * journal) can't be moved or wear leveled, so it contains just enough - * information to find the main journal, and the superblock only has to be - * rewritten when we want to move/wear level the main journal. - * - * JOURNAL LAYOUT ON DISK: - * - * The journal is written to a ringbuffer of buckets (which is kept in the - * superblock); the individual buckets are not necessarily contiguous on disk - * which means that journal entries are not allowed to span buckets, but also - * that we can resize the journal at runtime if desired (unimplemented). - * - * The journal buckets exist in the same pool as all the other buckets that are - * managed by the allocator and garbage collection - garbage collection marks - * the journal buckets as metadata buckets. - * - * OPEN/DIRTY JOURNAL ENTRIES: - * - * Open/dirty journal entries are journal entries that contain b-tree updates - * that have not yet been written out to the b-tree on disk. We have to track - * which journal entries are dirty, and we also have to avoid wrapping around - * the journal and overwriting old but still dirty journal entries with new - * journal entries. - * - * On disk, this is represented with the "last_seq" field of struct jset; - * last_seq is the first sequence number that journal replay has to replay. - * - * To avoid overwriting dirty journal entries on disk, we keep a mapping (in - * journal_device->seq) of for each journal bucket, the highest sequence number - * any journal entry it contains. Then, by comparing that against last_seq we - * can determine whether that journal bucket contains dirty journal entries or - * not. - * - * To track which journal entries are dirty, we maintain a fifo of refcounts - * (where each entry corresponds to a specific sequence number) - when a ref - * goes to 0, that journal entry is no longer dirty. - * - * Journalling of index updates is done at the same time as the b-tree itself is - * being modified (see btree_insert_key()); when we add the key to the journal - * the pending b-tree write takes a ref on the journal entry the key was added - * to. If a pending b-tree write would need to take refs on multiple dirty - * journal entries, it only keeps the ref on the oldest one (since a newer - * journal entry will still be replayed if an older entry was dirty). - * - * JOURNAL FILLING UP: - * - * There are two ways the journal could fill up; either we could run out of - * space to write to, or we could have too many open journal entries and run out - * of room in the fifo of refcounts. Since those refcounts are decremented - * without any locking we can't safely resize that fifo, so we handle it the - * same way. - * - * If the journal fills up, we start flushing dirty btree nodes until we can - * allocate space for a journal write again - preferentially flushing btree - * nodes that are pinning the oldest journal entries first. - */ - -#include - -#include "journal_types.h" - -/* - * Only used for holding the journal entries we read in btree_journal_read() - * during cache_registration - */ -struct journal_replay { - struct list_head list; - struct jset j; -}; - -static inline struct jset_entry *__jset_entry_type_next(struct jset *jset, - struct jset_entry *entry, unsigned type) -{ - while (entry < vstruct_last(jset)) { - if (JOURNAL_ENTRY_TYPE(entry) == type) - return entry; - - entry = vstruct_next(entry); - } - - return NULL; -} - -#define for_each_jset_entry_type(entry, jset, type) \ - for (entry = (jset)->start; \ - (entry = __jset_entry_type_next(jset, entry, type)); \ - entry = vstruct_next(entry)) - -#define for_each_jset_key(k, _n, entry, jset) \ - for_each_jset_entry_type(entry, jset, JOURNAL_ENTRY_BTREE_KEYS) \ - vstruct_for_each_safe(entry, k, _n) - -#define JOURNAL_PIN (32 * 1024) - -static inline bool journal_pin_active(struct journal_entry_pin *pin) -{ - return pin->pin_list != NULL; -} - -static inline struct journal_entry_pin_list * -journal_seq_pin(struct journal *j, u64 seq) -{ - return &j->pin.data[(size_t) seq & j->pin.mask]; -} - -void bch2_journal_pin_add(struct journal *, struct journal_res *, - struct journal_entry_pin *, journal_pin_flush_fn); -void bch2_journal_pin_drop(struct journal *, struct journal_entry_pin *); -void bch2_journal_pin_add_if_older(struct journal *, - struct journal_entry_pin *, - struct journal_entry_pin *, - journal_pin_flush_fn); -void bch2_journal_flush_pins(struct journal *, u64); - -struct closure; -struct bch_fs; -struct keylist; - -struct bkey_i *bch2_journal_find_btree_root(struct bch_fs *, struct jset *, - enum btree_id, unsigned *); - -int bch2_journal_seq_should_ignore(struct bch_fs *, u64, struct btree *); - -u64 bch2_inode_journal_seq(struct journal *, u64); - -static inline int journal_state_count(union journal_res_state s, int idx) -{ - return idx == 0 ? s.buf0_count : s.buf1_count; -} - -static inline void journal_state_inc(union journal_res_state *s) -{ - s->buf0_count += s->idx == 0; - s->buf1_count += s->idx == 1; -} - -static inline void bch2_journal_set_has_inode(struct journal_buf *buf, u64 inum) -{ - set_bit(hash_64(inum, ilog2(sizeof(buf->has_inode) * 8)), buf->has_inode); -} - -/* - * Amount of space that will be taken up by some keys in the journal (i.e. - * including the jset header) - */ -static inline unsigned jset_u64s(unsigned u64s) -{ - return u64s + sizeof(struct jset_entry) / sizeof(u64); -} - -static inline void bch2_journal_add_entry_at(struct journal_buf *buf, - const void *data, size_t u64s, - unsigned type, enum btree_id id, - unsigned level, unsigned offset) -{ - struct jset_entry *entry = vstruct_idx(buf->data, offset); - - entry->u64s = cpu_to_le16(u64s); - entry->btree_id = id; - entry->level = level; - entry->flags = 0; - SET_JOURNAL_ENTRY_TYPE(entry, type); - - memcpy_u64s(entry->_data, data, u64s); -} - -static inline void bch2_journal_add_keys(struct journal *j, struct journal_res *res, - enum btree_id id, const struct bkey_i *k) -{ - struct journal_buf *buf = &j->buf[res->idx]; - unsigned actual = jset_u64s(k->k.u64s); - - EBUG_ON(!res->ref); - BUG_ON(actual > res->u64s); - - bch2_journal_set_has_inode(buf, k->k.p.inode); - - bch2_journal_add_entry_at(buf, k, k->k.u64s, - JOURNAL_ENTRY_BTREE_KEYS, id, - 0, res->offset); - - res->offset += actual; - res->u64s -= actual; -} - -void bch2_journal_buf_put_slowpath(struct journal *, bool); - -static inline void bch2_journal_buf_put(struct journal *j, unsigned idx, - bool need_write_just_set) -{ - union journal_res_state s; - - s.v = atomic64_sub_return(((union journal_res_state) { - .buf0_count = idx == 0, - .buf1_count = idx == 1, - }).v, &j->reservations.counter); - - EBUG_ON(s.idx != idx && !s.prev_buf_unwritten); - - /* - * Do not initiate a journal write if the journal is in an error state - * (previous journal entry write may have failed) - */ - if (s.idx != idx && - !journal_state_count(s, idx) && - s.cur_entry_offset != JOURNAL_ENTRY_ERROR_VAL) - bch2_journal_buf_put_slowpath(j, need_write_just_set); -} - -/* - * This function releases the journal write structure so other threads can - * then proceed to add their keys as well. - */ -static inline void bch2_journal_res_put(struct journal *j, - struct journal_res *res) -{ - if (!res->ref) - return; - - lock_release(&j->res_map, 0, _RET_IP_); - - while (res->u64s) { - bch2_journal_add_entry_at(&j->buf[res->idx], NULL, 0, - JOURNAL_ENTRY_BTREE_KEYS, - 0, 0, res->offset); - res->offset += jset_u64s(0); - res->u64s -= jset_u64s(0); - } - - bch2_journal_buf_put(j, res->idx, false); - - res->ref = 0; -} - -int bch2_journal_res_get_slowpath(struct journal *, struct journal_res *, - unsigned, unsigned); - -static inline int journal_res_get_fast(struct journal *j, - struct journal_res *res, - unsigned u64s_min, - unsigned u64s_max) -{ - union journal_res_state old, new; - u64 v = atomic64_read(&j->reservations.counter); - - do { - old.v = new.v = v; - - /* - * Check if there is still room in the current journal - * entry: - */ - if (old.cur_entry_offset + u64s_min > j->cur_entry_u64s) - return 0; - - res->offset = old.cur_entry_offset; - res->u64s = min(u64s_max, j->cur_entry_u64s - - old.cur_entry_offset); - - journal_state_inc(&new); - new.cur_entry_offset += res->u64s; - } while ((v = atomic64_cmpxchg(&j->reservations.counter, - old.v, new.v)) != old.v); - - res->ref = true; - res->idx = new.idx; - res->seq = le64_to_cpu(j->buf[res->idx].data->seq); - return 1; -} - -static inline int bch2_journal_res_get(struct journal *j, struct journal_res *res, - unsigned u64s_min, unsigned u64s_max) -{ - int ret; - - EBUG_ON(res->ref); - EBUG_ON(u64s_max < u64s_min); - - if (journal_res_get_fast(j, res, u64s_min, u64s_max)) - goto out; - - ret = bch2_journal_res_get_slowpath(j, res, u64s_min, u64s_max); - if (ret) - return ret; -out: - lock_acquire_shared(&j->res_map, 0, 0, NULL, _THIS_IP_); - EBUG_ON(!res->ref); - return 0; -} - -void bch2_journal_wait_on_seq(struct journal *, u64, struct closure *); -void bch2_journal_flush_seq_async(struct journal *, u64, struct closure *); -void bch2_journal_flush_async(struct journal *, struct closure *); -void bch2_journal_meta_async(struct journal *, struct closure *); - -int bch2_journal_flush_seq(struct journal *, u64); -int bch2_journal_flush(struct journal *); -int bch2_journal_meta(struct journal *); - -void bch2_journal_halt(struct journal *); - -static inline int bch2_journal_error(struct journal *j) -{ - return j->reservations.cur_entry_offset == JOURNAL_ENTRY_ERROR_VAL - ? -EIO : 0; -} - -static inline bool journal_flushes_device(struct bch_dev *ca) -{ - return true; -} - -void bch2_journal_start(struct bch_fs *); -int bch2_journal_mark(struct bch_fs *, struct list_head *); -void bch2_journal_entries_free(struct list_head *); -int bch2_journal_read(struct bch_fs *, struct list_head *); -int bch2_journal_replay(struct bch_fs *, struct list_head *); - -static inline void bch2_journal_set_replay_done(struct journal *j) -{ - BUG_ON(!test_bit(JOURNAL_STARTED, &j->flags)); - set_bit(JOURNAL_REPLAY_DONE, &j->flags); -} - -ssize_t bch2_journal_print_debug(struct journal *, char *); -ssize_t bch2_journal_print_pins(struct journal *, char *); - -int bch2_dev_journal_alloc(struct bch_dev *); - -static inline unsigned bch2_nr_journal_buckets(struct bch_sb_field_journal *j) -{ - return j - ? (__le64 *) vstruct_end(&j->field) - j->buckets - : 0; -} - -int bch2_journal_move(struct bch_dev *); - -void bch2_fs_journal_stop(struct journal *); -void bch2_dev_journal_exit(struct bch_dev *); -int bch2_dev_journal_init(struct bch_dev *, struct bch_sb *); -void bch2_fs_journal_exit(struct journal *); -int bch2_fs_journal_init(struct journal *); - -#endif /* _BCACHE_JOURNAL_H */