+++ /dev/null
-#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 <linux/hash.h>
-
-#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 */
projects / bcachefs-tools-debian / blobdiff