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Diffstat (limited to 'c_src/libbcachefs/journal.h')
| -rw-r--r-- | c_src/libbcachefs/journal.h | 448 |
1 files changed, 0 insertions, 448 deletions
diff --git a/c_src/libbcachefs/journal.h b/c_src/libbcachefs/journal.h deleted file mode 100644 index 4544ce24..00000000 --- a/c_src/libbcachefs/journal.h +++ /dev/null @@ -1,448 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _BCACHEFS_JOURNAL_H -#define _BCACHEFS_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 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 <linux/hash.h> - -#include "journal_types.h" - -struct bch_fs; - -static inline void journal_wake(struct journal *j) -{ - wake_up(&j->wait); - closure_wake_up(&j->async_wait); -} - -static inline struct journal_buf *journal_cur_buf(struct journal *j) -{ - return j->buf + j->reservations.idx; -} - -/* Sequence number of oldest dirty journal entry */ - -static inline u64 journal_last_seq(struct journal *j) -{ - return j->pin.front; -} - -static inline u64 journal_cur_seq(struct journal *j) -{ - return atomic64_read(&j->seq); -} - -static inline u64 journal_last_unwritten_seq(struct journal *j) -{ - return j->seq_ondisk + 1; -} - -static inline int journal_state_count(union journal_res_state s, int idx) -{ - switch (idx) { - case 0: return s.buf0_count; - case 1: return s.buf1_count; - case 2: return s.buf2_count; - case 3: return s.buf3_count; - } - BUG(); -} - -static inline void journal_state_inc(union journal_res_state *s) -{ - s->buf0_count += s->idx == 0; - s->buf1_count += s->idx == 1; - s->buf2_count += s->idx == 2; - s->buf3_count += s->idx == 3; -} - -/* - * 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 int journal_entry_overhead(struct journal *j) -{ - return sizeof(struct jset) / sizeof(u64) + j->entry_u64s_reserved; -} - -static inline struct jset_entry * -bch2_journal_add_entry_noreservation(struct journal_buf *buf, size_t u64s) -{ - struct jset *jset = buf->data; - struct jset_entry *entry = vstruct_idx(jset, le32_to_cpu(jset->u64s)); - - memset(entry, 0, sizeof(*entry)); - entry->u64s = cpu_to_le16(u64s); - - le32_add_cpu(&jset->u64s, jset_u64s(u64s)); - - return entry; -} - -static inline struct jset_entry * -journal_res_entry(struct journal *j, struct journal_res *res) -{ - return vstruct_idx(j->buf[res->idx].data, res->offset); -} - -static inline unsigned journal_entry_init(struct jset_entry *entry, unsigned type, - enum btree_id id, unsigned level, - unsigned u64s) -{ - entry->u64s = cpu_to_le16(u64s); - entry->btree_id = id; - entry->level = level; - entry->type = type; - entry->pad[0] = 0; - entry->pad[1] = 0; - entry->pad[2] = 0; - return jset_u64s(u64s); -} - -static inline unsigned journal_entry_set(struct jset_entry *entry, unsigned type, - enum btree_id id, unsigned level, - const void *data, unsigned u64s) -{ - unsigned ret = journal_entry_init(entry, type, id, level, u64s); - - memcpy_u64s_small(entry->_data, data, u64s); - return ret; -} - -static inline struct jset_entry * -bch2_journal_add_entry(struct journal *j, struct journal_res *res, - unsigned type, enum btree_id id, - unsigned level, unsigned u64s) -{ - struct jset_entry *entry = journal_res_entry(j, res); - unsigned actual = journal_entry_init(entry, type, id, level, u64s); - - EBUG_ON(!res->ref); - EBUG_ON(actual > res->u64s); - - res->offset += actual; - res->u64s -= actual; - return entry; -} - -static inline bool journal_entry_empty(struct jset *j) -{ - if (j->seq != j->last_seq) - return false; - - vstruct_for_each(j, i) - if (i->type == BCH_JSET_ENTRY_btree_keys && i->u64s) - return false; - return true; -} - -/* - * Drop reference on a buffer index and return true if the count has hit zero. - */ -static inline union journal_res_state journal_state_buf_put(struct journal *j, unsigned idx) -{ - union journal_res_state s; - - s.v = atomic64_sub_return(((union journal_res_state) { - .buf0_count = idx == 0, - .buf1_count = idx == 1, - .buf2_count = idx == 2, - .buf3_count = idx == 3, - }).v, &j->reservations.counter); - return s; -} - -bool bch2_journal_entry_close(struct journal *); -void bch2_journal_buf_put_final(struct journal *, u64, bool); - -static inline void __bch2_journal_buf_put(struct journal *j, unsigned idx, u64 seq) -{ - union journal_res_state s; - - s = journal_state_buf_put(j, idx); - if (!journal_state_count(s, idx)) - bch2_journal_buf_put_final(j, seq, idx == s.unwritten_idx); -} - -static inline void bch2_journal_buf_put(struct journal *j, unsigned idx, u64 seq) -{ - union journal_res_state s; - - s = journal_state_buf_put(j, idx); - if (!journal_state_count(s, idx)) { - spin_lock(&j->lock); - bch2_journal_buf_put_final(j, seq, idx == s.unwritten_idx); - spin_unlock(&j->lock); - } -} - -/* - * 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, _THIS_IP_); - - while (res->u64s) - bch2_journal_add_entry(j, res, - BCH_JSET_ENTRY_btree_keys, - 0, 0, 0); - - bch2_journal_buf_put(j, res->idx, res->seq); - - res->ref = 0; -} - -int bch2_journal_res_get_slowpath(struct journal *, struct journal_res *, - unsigned); - -/* First bits for BCH_WATERMARK: */ -enum journal_res_flags { - __JOURNAL_RES_GET_NONBLOCK = BCH_WATERMARK_BITS, - __JOURNAL_RES_GET_CHECK, -}; - -#define JOURNAL_RES_GET_NONBLOCK (1 << __JOURNAL_RES_GET_NONBLOCK) -#define JOURNAL_RES_GET_CHECK (1 << __JOURNAL_RES_GET_CHECK) - -static inline int journal_res_get_fast(struct journal *j, - struct journal_res *res, - unsigned flags) -{ - 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 (new.cur_entry_offset + res->u64s > j->cur_entry_u64s) - return 0; - - EBUG_ON(!journal_state_count(new, new.idx)); - - if ((flags & BCH_WATERMARK_MASK) < j->watermark) - return 0; - - new.cur_entry_offset += res->u64s; - journal_state_inc(&new); - - /* - * If the refcount would overflow, we have to wait: - * XXX - tracepoint this: - */ - if (!journal_state_count(new, new.idx)) - return 0; - - if (flags & JOURNAL_RES_GET_CHECK) - return 1; - } while ((v = atomic64_cmpxchg(&j->reservations.counter, - old.v, new.v)) != old.v); - - res->ref = true; - res->idx = old.idx; - res->offset = old.cur_entry_offset; - res->seq = le64_to_cpu(j->buf[old.idx].data->seq); - return 1; -} - -static inline int bch2_journal_res_get(struct journal *j, struct journal_res *res, - unsigned u64s, unsigned flags) -{ - int ret; - - EBUG_ON(res->ref); - EBUG_ON(!test_bit(JOURNAL_STARTED, &j->flags)); - - res->u64s = u64s; - - if (journal_res_get_fast(j, res, flags)) - goto out; - - ret = bch2_journal_res_get_slowpath(j, res, flags); - if (ret) - return ret; -out: - if (!(flags & JOURNAL_RES_GET_CHECK)) { - lock_acquire_shared(&j->res_map, 0, - (flags & JOURNAL_RES_GET_NONBLOCK) != 0, - NULL, _THIS_IP_); - EBUG_ON(!res->ref); - } - return 0; -} - -/* journal_entry_res: */ - -void bch2_journal_entry_res_resize(struct journal *, - struct journal_entry_res *, - unsigned); - -int bch2_journal_flush_seq_async(struct journal *, u64, struct closure *); -void bch2_journal_flush_async(struct journal *, struct closure *); - -int bch2_journal_flush_seq(struct journal *, u64); -int bch2_journal_flush(struct journal *); -bool bch2_journal_noflush_seq(struct journal *, u64); -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; -} - -struct bch_dev; - -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); -} - -void bch2_journal_unblock(struct journal *); -void bch2_journal_block(struct journal *); -struct journal_buf *bch2_next_write_buffer_flush_journal_buf(struct journal *j, u64 max_seq); - -void __bch2_journal_debug_to_text(struct printbuf *, struct journal *); -void bch2_journal_debug_to_text(struct printbuf *, struct journal *); -void bch2_journal_pins_to_text(struct printbuf *, struct journal *); -bool bch2_journal_seq_pins_to_text(struct printbuf *, struct journal *, u64 *); - -int bch2_set_nr_journal_buckets(struct bch_fs *, struct bch_dev *, - unsigned nr); -int bch2_dev_journal_alloc(struct bch_dev *); -int bch2_fs_journal_alloc(struct bch_fs *); - -void bch2_dev_journal_stop(struct journal *, struct bch_dev *); - -void bch2_fs_journal_stop(struct journal *); -int bch2_fs_journal_start(struct journal *, u64); - -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 /* _BCACHEFS_JOURNAL_H */ |