linux/fs/bcachefs/btree_iter.h

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_BTREE_ITER_H
#define _BCACHEFS_BTREE_ITER_H
#include "bset.h"
#include "btree_types.h"
#include "trace.h"
static inline int __bkey_err(const struct bkey *k)
{
return PTR_ERR_OR_ZERO(k);
}
#define bkey_err(_k) __bkey_err((_k).k)
static inline void __btree_path_get(struct btree_path *path, bool intent)
{
path->ref++;
path->intent_ref += intent;
}
static inline bool __btree_path_put(struct btree_path *path, bool intent)
{
EBUG_ON(!path->ref);
EBUG_ON(!path->intent_ref && intent);
path->intent_ref -= intent;
return --path->ref == 0;
}
static inline void btree_path_set_dirty(struct btree_path *path,
enum btree_path_uptodate u)
{
path->uptodate = max_t(unsigned, path->uptodate, u);
}
static inline struct btree *btree_path_node(struct btree_path *path,
unsigned level)
{
return level < BTREE_MAX_DEPTH ? path->l[level].b : NULL;
}
static inline bool btree_node_lock_seq_matches(const struct btree_path *path,
const struct btree *b, unsigned level)
{
/*
* We don't compare the low bits of the lock sequence numbers because
* @path might have taken a write lock on @b, and we don't want to skip
* the linked path if the sequence numbers were equal before taking that
* write lock. The lock sequence number is incremented by taking and
* releasing write locks and is even when unlocked:
*/
return path->l[level].lock_seq >> 1 == six_lock_seq(&b->c.lock) >> 1;
}
static inline struct btree *btree_node_parent(struct btree_path *path,
struct btree *b)
{
return btree_path_node(path, b->c.level + 1);
}
/* Iterate over paths within a transaction: */
void __bch2_btree_trans_sort_paths(struct btree_trans *);
static inline void btree_trans_sort_paths(struct btree_trans *trans)
{
if (!IS_ENABLED(CONFIG_BCACHEFS_DEBUG) &&
trans->paths_sorted)
return;
__bch2_btree_trans_sort_paths(trans);
}
static inline struct btree_path *
__trans_next_path(struct btree_trans *trans, unsigned idx)
{
u64 l;
if (idx == BTREE_ITER_MAX)
return NULL;
l = trans->paths_allocated >> idx;
if (!l)
return NULL;
idx += __ffs64(l);
EBUG_ON(idx >= BTREE_ITER_MAX);
EBUG_ON(trans->paths[idx].idx != idx);
return &trans->paths[idx];
}
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
#define trans_for_each_path_from(_trans, _path, _start) \
for (_path = __trans_next_path((_trans), _start); \
(_path); \
_path = __trans_next_path((_trans), (_path)->idx + 1))
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
#define trans_for_each_path(_trans, _path) \
trans_for_each_path_from(_trans, _path, 0)
static inline struct btree_path *next_btree_path(struct btree_trans *trans, struct btree_path *path)
{
unsigned idx = path ? path->sorted_idx + 1 : 0;
EBUG_ON(idx > trans->nr_sorted);
return idx < trans->nr_sorted
? trans->paths + trans->sorted[idx]
: NULL;
}
static inline struct btree_path *prev_btree_path(struct btree_trans *trans, struct btree_path *path)
{
unsigned idx = path ? path->sorted_idx : trans->nr_sorted;
return idx
? trans->paths + trans->sorted[idx - 1]
: NULL;
}
#define trans_for_each_path_inorder(_trans, _path, _i) \
for (_i = 0; \
((_path) = (_trans)->paths + trans->sorted[_i]), (_i) < (_trans)->nr_sorted;\
_i++)
#define trans_for_each_path_inorder_reverse(_trans, _path, _i) \
for (_i = trans->nr_sorted - 1; \
((_path) = (_trans)->paths + trans->sorted[_i]), (_i) >= 0;\
--_i)
static inline bool __path_has_node(const struct btree_path *path,
const struct btree *b)
{
return path->l[b->c.level].b == b &&
btree_node_lock_seq_matches(path, b, b->c.level);
}
static inline struct btree_path *
__trans_next_path_with_node(struct btree_trans *trans, struct btree *b,
unsigned idx)
{
struct btree_path *path = __trans_next_path(trans, idx);
while (path && !__path_has_node(path, b))
path = __trans_next_path(trans, path->idx + 1);
return path;
}
#define trans_for_each_path_with_node(_trans, _b, _path) \
for (_path = __trans_next_path_with_node((_trans), (_b), 0); \
(_path); \
_path = __trans_next_path_with_node((_trans), (_b), \
(_path)->idx + 1))
struct btree_path *__bch2_btree_path_make_mut(struct btree_trans *, struct btree_path *,
bool, unsigned long);
static inline struct btree_path * __must_check
bch2_btree_path_make_mut(struct btree_trans *trans,
struct btree_path *path, bool intent,
unsigned long ip)
{
if (path->ref > 1 || path->preserve)
path = __bch2_btree_path_make_mut(trans, path, intent, ip);
path->should_be_locked = false;
return path;
}
struct btree_path * __must_check
__bch2_btree_path_set_pos(struct btree_trans *, struct btree_path *,
struct bpos, bool, unsigned long, int);
static inline struct btree_path * __must_check
bch2_btree_path_set_pos(struct btree_trans *trans,
struct btree_path *path, struct bpos new_pos,
bool intent, unsigned long ip)
{
int cmp = bpos_cmp(new_pos, path->pos);
return cmp
? __bch2_btree_path_set_pos(trans, path, new_pos, intent, ip, cmp)
: path;
}
int __must_check bch2_btree_path_traverse_one(struct btree_trans *, struct btree_path *,
unsigned, unsigned long);
static inline int __must_check bch2_btree_path_traverse(struct btree_trans *trans,
struct btree_path *path, unsigned flags)
{
if (path->uptodate < BTREE_ITER_NEED_RELOCK)
return 0;
return bch2_btree_path_traverse_one(trans, path, flags, _RET_IP_);
}
int __must_check bch2_btree_path_traverse(struct btree_trans *,
struct btree_path *, unsigned);
struct btree_path *bch2_path_get(struct btree_trans *, enum btree_id, struct bpos,
unsigned, unsigned, unsigned, unsigned long);
struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *, struct bkey *);
struct bkey_i *bch2_btree_journal_peek_slot(struct btree_trans *,
struct btree_iter *, struct bpos);
void bch2_btree_path_level_init(struct btree_trans *, struct btree_path *, struct btree *);
int __bch2_trans_mutex_lock(struct btree_trans *, struct mutex *);
static inline int bch2_trans_mutex_lock(struct btree_trans *trans, struct mutex *lock)
{
return mutex_trylock(lock)
? 0
: __bch2_trans_mutex_lock(trans, lock);
}
#ifdef CONFIG_BCACHEFS_DEBUG
void bch2_trans_verify_paths(struct btree_trans *);
void bch2_assert_pos_locked(struct btree_trans *, enum btree_id,
struct bpos, bool);
#else
static inline void bch2_trans_verify_paths(struct btree_trans *trans) {}
static inline void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
struct bpos pos, bool key_cache) {}
#endif
void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
struct btree *, struct bkey_packed *);
void bch2_btree_node_iter_fix(struct btree_trans *trans, struct btree_path *,
struct btree *, struct btree_node_iter *,
struct bkey_packed *, unsigned, unsigned);
int bch2_btree_path_relock_intent(struct btree_trans *, struct btree_path *);
void bch2_path_put(struct btree_trans *, struct btree_path *, bool);
int bch2_trans_relock(struct btree_trans *);
int bch2_trans_relock_notrace(struct btree_trans *);
void bch2_trans_unlock(struct btree_trans *);
bool bch2_trans_locked(struct btree_trans *);
static inline bool trans_was_restarted(struct btree_trans *trans, u32 restart_count)
{
return restart_count != trans->restart_count;
}
void __noreturn bch2_trans_restart_error(struct btree_trans *, u32);
static inline void bch2_trans_verify_not_restarted(struct btree_trans *trans,
u32 restart_count)
{
if (trans_was_restarted(trans, restart_count))
bch2_trans_restart_error(trans, restart_count);
}
void __noreturn bch2_trans_in_restart_error(struct btree_trans *);
static inline void bch2_trans_verify_not_in_restart(struct btree_trans *trans)
{
if (trans->restarted)
bch2_trans_in_restart_error(trans);
}
__always_inline
static inline int btree_trans_restart_nounlock(struct btree_trans *trans, int err)
{
BUG_ON(err <= 0);
BUG_ON(!bch2_err_matches(err, BCH_ERR_transaction_restart));
trans->restarted = err;
trans->last_restarted_ip = _THIS_IP_;
return -err;
}
__always_inline
static inline int btree_trans_restart(struct btree_trans *trans, int err)
{
btree_trans_restart_nounlock(trans, err);
return -err;
}
bool bch2_btree_node_upgrade(struct btree_trans *,
struct btree_path *, unsigned);
void __bch2_btree_path_downgrade(struct btree_trans *, struct btree_path *, unsigned);
static inline void bch2_btree_path_downgrade(struct btree_trans *trans,
struct btree_path *path)
{
unsigned new_locks_want = path->level + !!path->intent_ref;
if (path->locks_want > new_locks_want)
__bch2_btree_path_downgrade(trans, path, new_locks_want);
}
void bch2_trans_downgrade(struct btree_trans *);
void bch2_trans_node_add(struct btree_trans *trans, struct btree *);
void bch2_trans_node_reinit_iter(struct btree_trans *, struct btree *);
int __must_check __bch2_btree_iter_traverse(struct btree_iter *iter);
int __must_check bch2_btree_iter_traverse(struct btree_iter *);
struct btree *bch2_btree_iter_peek_node(struct btree_iter *);
struct btree *bch2_btree_iter_peek_node_and_restart(struct btree_iter *);
struct btree *bch2_btree_iter_next_node(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *, struct bpos);
struct bkey_s_c bch2_btree_iter_next(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_peek_all_levels(struct btree_iter *);
static inline struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)
{
return bch2_btree_iter_peek_upto(iter, SPOS_MAX);
}
struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *);
struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *);
bool bch2_btree_iter_advance(struct btree_iter *);
bool bch2_btree_iter_rewind(struct btree_iter *);
static inline void __bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
{
iter->k.type = KEY_TYPE_deleted;
iter->k.p.inode = iter->pos.inode = new_pos.inode;
iter->k.p.offset = iter->pos.offset = new_pos.offset;
iter->k.p.snapshot = iter->pos.snapshot = new_pos.snapshot;
iter->k.size = 0;
}
static inline void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
{
if (unlikely(iter->update_path))
bch2_path_put(iter->trans, iter->update_path,
iter->flags & BTREE_ITER_INTENT);
iter->update_path = NULL;
if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
new_pos.snapshot = iter->snapshot;
__bch2_btree_iter_set_pos(iter, new_pos);
}
static inline void bch2_btree_iter_set_pos_to_extent_start(struct btree_iter *iter)
{
BUG_ON(!(iter->flags & BTREE_ITER_IS_EXTENTS));
iter->pos = bkey_start_pos(&iter->k);
}
static inline void bch2_btree_iter_set_snapshot(struct btree_iter *iter, u32 snapshot)
{
struct bpos pos = iter->pos;
iter->snapshot = snapshot;
pos.snapshot = snapshot;
bch2_btree_iter_set_pos(iter, pos);
}
void bch2_trans_iter_exit(struct btree_trans *, struct btree_iter *);
static inline unsigned __bch2_btree_iter_flags(struct btree_trans *trans,
unsigned btree_id,
unsigned flags)
{
if (flags & BTREE_ITER_ALL_LEVELS)
flags |= BTREE_ITER_ALL_SNAPSHOTS|__BTREE_ITER_ALL_SNAPSHOTS;
if (!(flags & (BTREE_ITER_ALL_SNAPSHOTS|BTREE_ITER_NOT_EXTENTS)) &&
btree_node_type_is_extents(btree_id))
flags |= BTREE_ITER_IS_EXTENTS;
if (!(flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
!btree_type_has_snapshots(btree_id))
flags &= ~BTREE_ITER_ALL_SNAPSHOTS;
if (!(flags & BTREE_ITER_ALL_SNAPSHOTS) &&
btree_type_has_snapshots(btree_id))
flags |= BTREE_ITER_FILTER_SNAPSHOTS;
if (trans->journal_replay_not_finished)
flags |= BTREE_ITER_WITH_JOURNAL;
return flags;
}
static inline unsigned bch2_btree_iter_flags(struct btree_trans *trans,
unsigned btree_id,
unsigned flags)
{
if (!btree_id_cached(trans->c, btree_id)) {
flags &= ~BTREE_ITER_CACHED;
flags &= ~BTREE_ITER_WITH_KEY_CACHE;
} else if (!(flags & BTREE_ITER_CACHED))
flags |= BTREE_ITER_WITH_KEY_CACHE;
return __bch2_btree_iter_flags(trans, btree_id, flags);
}
static inline void bch2_trans_iter_init_common(struct btree_trans *trans,
struct btree_iter *iter,
unsigned btree_id, struct bpos pos,
unsigned locks_want,
unsigned depth,
unsigned flags,
unsigned long ip)
{
memset(iter, 0, sizeof(*iter));
iter->trans = trans;
iter->btree_id = btree_id;
iter->flags = flags;
iter->snapshot = pos.snapshot;
iter->pos = pos;
iter->k.p = pos;
#ifdef CONFIG_BCACHEFS_DEBUG
iter->ip_allocated = ip;
#endif
iter->path = bch2_path_get(trans, btree_id, iter->pos,
locks_want, depth, flags, ip);
}
void bch2_trans_iter_init_outlined(struct btree_trans *, struct btree_iter *,
enum btree_id, struct bpos, unsigned);
static inline void bch2_trans_iter_init(struct btree_trans *trans,
struct btree_iter *iter,
unsigned btree_id, struct bpos pos,
unsigned flags)
{
if (__builtin_constant_p(btree_id) &&
__builtin_constant_p(flags))
bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
bch2_btree_iter_flags(trans, btree_id, flags),
_THIS_IP_);
else
bch2_trans_iter_init_outlined(trans, iter, btree_id, pos, flags);
}
void bch2_trans_node_iter_init(struct btree_trans *, struct btree_iter *,
enum btree_id, struct bpos,
unsigned, unsigned, unsigned);
void bch2_trans_copy_iter(struct btree_iter *, struct btree_iter *);
static inline void set_btree_iter_dontneed(struct btree_iter *iter)
{
if (!iter->trans->restarted)
iter->path->preserve = false;
}
void *__bch2_trans_kmalloc(struct btree_trans *, size_t);
static inline void *bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
{
size = roundup(size, 8);
if (likely(trans->mem_top + size <= trans->mem_bytes)) {
void *p = trans->mem + trans->mem_top;
trans->mem_top += size;
memset(p, 0, size);
return p;
} else {
return __bch2_trans_kmalloc(trans, size);
}
}
static inline void *bch2_trans_kmalloc_nomemzero(struct btree_trans *trans, size_t size)
{
size = roundup(size, 8);
if (likely(trans->mem_top + size <= trans->mem_bytes)) {
void *p = trans->mem + trans->mem_top;
trans->mem_top += size;
return p;
} else {
return __bch2_trans_kmalloc(trans, size);
}
}
static inline struct bkey_s_c __bch2_bkey_get_iter(struct btree_trans *trans,
struct btree_iter *iter,
unsigned btree_id, struct bpos pos,
unsigned flags, unsigned type)
{
struct bkey_s_c k;
bch2_trans_iter_init(trans, iter, btree_id, pos, flags);
k = bch2_btree_iter_peek_slot(iter);
if (!bkey_err(k) && type && k.k->type != type)
k = bkey_s_c_err(-ENOENT);
if (unlikely(bkey_err(k)))
bch2_trans_iter_exit(trans, iter);
return k;
}
static inline struct bkey_s_c bch2_bkey_get_iter(struct btree_trans *trans,
struct btree_iter *iter,
unsigned btree_id, struct bpos pos,
unsigned flags)
{
return __bch2_bkey_get_iter(trans, iter, btree_id, pos, flags, 0);
}
#define bch2_bkey_get_iter_typed(_trans, _iter, _btree_id, _pos, _flags, _type)\
bkey_s_c_to_##_type(__bch2_bkey_get_iter(_trans, _iter, \
_btree_id, _pos, _flags, KEY_TYPE_##_type))
static inline int __bch2_bkey_get_val_typed(struct btree_trans *trans,
unsigned btree_id, struct bpos pos,
unsigned flags, unsigned type,
unsigned val_size, void *val)
{
struct btree_iter iter;
struct bkey_s_c k;
int ret;
k = __bch2_bkey_get_iter(trans, &iter, btree_id, pos, flags, type);
ret = bkey_err(k);
if (!ret) {
unsigned b = min_t(unsigned, bkey_val_bytes(k.k), val_size);
memcpy(val, k.v, b);
if (unlikely(b < sizeof(*val)))
memset((void *) val + b, 0, sizeof(*val) - b);
bch2_trans_iter_exit(trans, &iter);
}
return ret;
}
#define bch2_bkey_get_val_typed(_trans, _btree_id, _pos, _flags, _type, _val)\
__bch2_bkey_get_val_typed(_trans, _btree_id, _pos, _flags, \
KEY_TYPE_##_type, sizeof(*_val), _val)
u32 bch2_trans_begin(struct btree_trans *);
/*
* XXX
* this does not handle transaction restarts from bch2_btree_iter_next_node()
* correctly
*/
#define __for_each_btree_node(_trans, _iter, _btree_id, _start, \
_locks_want, _depth, _flags, _b, _ret) \
for (bch2_trans_node_iter_init((_trans), &(_iter), (_btree_id), \
_start, _locks_want, _depth, _flags); \
(_b) = bch2_btree_iter_peek_node_and_restart(&(_iter)), \
!((_ret) = PTR_ERR_OR_ZERO(_b)) && (_b); \
(_b) = bch2_btree_iter_next_node(&(_iter)))
#define for_each_btree_node(_trans, _iter, _btree_id, _start, \
_flags, _b, _ret) \
__for_each_btree_node(_trans, _iter, _btree_id, _start, \
0, 0, _flags, _b, _ret)
static inline struct bkey_s_c bch2_btree_iter_peek_prev_type(struct btree_iter *iter,
unsigned flags)
{
BUG_ON(flags & BTREE_ITER_ALL_LEVELS);
return flags & BTREE_ITER_SLOTS ? bch2_btree_iter_peek_slot(iter) :
bch2_btree_iter_peek_prev(iter);
}
static inline struct bkey_s_c bch2_btree_iter_peek_type(struct btree_iter *iter,
unsigned flags)
{
return flags & BTREE_ITER_ALL_LEVELS ? bch2_btree_iter_peek_all_levels(iter) :
flags & BTREE_ITER_SLOTS ? bch2_btree_iter_peek_slot(iter) :
bch2_btree_iter_peek(iter);
}
static inline struct bkey_s_c bch2_btree_iter_peek_upto_type(struct btree_iter *iter,
struct bpos end,
unsigned flags)
{
if (!(flags & BTREE_ITER_SLOTS))
return bch2_btree_iter_peek_upto(iter, end);
if (bkey_gt(iter->pos, end))
return bkey_s_c_null;
return bch2_btree_iter_peek_slot(iter);
}
static inline int btree_trans_too_many_iters(struct btree_trans *trans)
{
if (hweight64(trans->paths_allocated) > BTREE_ITER_MAX - 8) {
trace_and_count(trans->c, trans_restart_too_many_iters, trans, _THIS_IP_);
return btree_trans_restart(trans, BCH_ERR_transaction_restart_too_many_iters);
}
return 0;
}
struct bkey_s_c bch2_btree_iter_peek_and_restart_outlined(struct btree_iter *);
static inline struct bkey_s_c
__bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
struct btree_iter *iter, unsigned flags)
{
struct bkey_s_c k;
while (btree_trans_too_many_iters(trans) ||
(k = bch2_btree_iter_peek_type(iter, flags),
bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
bch2_trans_begin(trans);
return k;
}
static inline struct bkey_s_c
__bch2_btree_iter_peek_upto_and_restart(struct btree_trans *trans,
struct btree_iter *iter,
struct bpos end,
unsigned flags)
{
struct bkey_s_c k;
while (btree_trans_too_many_iters(trans) ||
(k = bch2_btree_iter_peek_upto_type(iter, end, flags),
bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
bch2_trans_begin(trans);
return k;
}
#define lockrestart_do(_trans, _do) \
({ \
u32 _restart_count; \
int _ret; \
\
do { \
_restart_count = bch2_trans_begin(_trans); \
_ret = (_do); \
} while (bch2_err_matches(_ret, BCH_ERR_transaction_restart)); \
\
if (!_ret) \
bch2_trans_verify_not_restarted(_trans, _restart_count);\
\
_ret; \
})
/*
* nested_lockrestart_do(), nested_commit_do():
*
* These are like lockrestart_do() and commit_do(), with two differences:
*
* - We don't call bch2_trans_begin() unless we had a transaction restart
* - We return -BCH_ERR_transaction_restart_nested if we succeeded after a
* transaction restart
*/
#define nested_lockrestart_do(_trans, _do) \
({ \
u32 _restart_count, _orig_restart_count; \
int _ret; \
\
_restart_count = _orig_restart_count = (_trans)->restart_count; \
\
while (bch2_err_matches(_ret = (_do), BCH_ERR_transaction_restart))\
_restart_count = bch2_trans_begin(_trans); \
\
if (!_ret) \
bch2_trans_verify_not_restarted(_trans, _restart_count);\
\
if (!_ret && trans_was_restarted(_trans, _orig_restart_count)) \
_ret = -BCH_ERR_transaction_restart_nested; \
\
_ret; \
})
#define for_each_btree_key2(_trans, _iter, _btree_id, \
_start, _flags, _k, _do) \
({ \
int _ret = 0; \
\
bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
\
while (1) { \
u32 _restart_count = bch2_trans_begin(_trans); \
\
_ret = 0; \
(_k) = bch2_btree_iter_peek_type(&(_iter), (_flags)); \
if (!(_k).k) \
break; \
\
_ret = bkey_err(_k) ?: (_do); \
if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
continue; \
if (_ret) \
break; \
bch2_trans_verify_not_restarted(_trans, _restart_count);\
if (!bch2_btree_iter_advance(&(_iter))) \
break; \
} \
\
bch2_trans_iter_exit((_trans), &(_iter)); \
_ret; \
})
#define for_each_btree_key2_upto(_trans, _iter, _btree_id, \
_start, _end, _flags, _k, _do) \
({ \
int _ret = 0; \
\
bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
\
while (1) { \
u32 _restart_count = bch2_trans_begin(_trans); \
\
_ret = 0; \
(_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, (_flags));\
if (!(_k).k) \
break; \
\
_ret = bkey_err(_k) ?: (_do); \
if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
continue; \
if (_ret) \
break; \
bch2_trans_verify_not_restarted(_trans, _restart_count);\
if (!bch2_btree_iter_advance(&(_iter))) \
break; \
} \
\
bch2_trans_iter_exit((_trans), &(_iter)); \
_ret; \
})
#define for_each_btree_key_reverse(_trans, _iter, _btree_id, \
_start, _flags, _k, _do) \
({ \
int _ret = 0; \
\
bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
\
while (1) { \
u32 _restart_count = bch2_trans_begin(_trans); \
(_k) = bch2_btree_iter_peek_prev_type(&(_iter), (_flags));\
if (!(_k).k) { \
_ret = 0; \
break; \
} \
\
_ret = bkey_err(_k) ?: (_do); \
if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
continue; \
if (_ret) \
break; \
bch2_trans_verify_not_restarted(_trans, _restart_count);\
if (!bch2_btree_iter_rewind(&(_iter))) \
break; \
} \
\
bch2_trans_iter_exit((_trans), &(_iter)); \
_ret; \
})
#define for_each_btree_key_commit(_trans, _iter, _btree_id, \
_start, _iter_flags, _k, \
_disk_res, _journal_seq, _commit_flags,\
_do) \
for_each_btree_key2(_trans, _iter, _btree_id, _start, _iter_flags, _k,\
(_do) ?: bch2_trans_commit(_trans, (_disk_res),\
(_journal_seq), (_commit_flags)))
#define for_each_btree_key_upto_commit(_trans, _iter, _btree_id, \
_start, _end, _iter_flags, _k, \
_disk_res, _journal_seq, _commit_flags,\
_do) \
for_each_btree_key2_upto(_trans, _iter, _btree_id, _start, _end, _iter_flags, _k,\
(_do) ?: bch2_trans_commit(_trans, (_disk_res),\
(_journal_seq), (_commit_flags)))
#define for_each_btree_key(_trans, _iter, _btree_id, \
_start, _flags, _k, _ret) \
for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
(_k) = __bch2_btree_iter_peek_and_restart((_trans), &(_iter), _flags),\
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_upto(_trans, _iter, _btree_id, \
_start, _end, _flags, _k, _ret) \
for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
(_k) = __bch2_btree_iter_peek_upto_and_restart((_trans), \
&(_iter), _end, _flags),\
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_norestart(_trans, _iter, _btree_id, \
_start, _flags, _k, _ret) \
for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
(_k) = bch2_btree_iter_peek_type(&(_iter), _flags), \
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_upto_norestart(_trans, _iter, _btree_id, \
_start, _end, _flags, _k, _ret) \
for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id), \
(_start), (_flags)); \
(_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, _flags),\
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_continue(_trans, _iter, _flags, _k, _ret) \
for (; \
(_k) = __bch2_btree_iter_peek_and_restart((_trans), &(_iter), _flags),\
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_continue_norestart(_iter, _flags, _k, _ret) \
for (; \
(_k) = bch2_btree_iter_peek_type(&(_iter), _flags), \
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
#define for_each_btree_key_upto_continue_norestart(_iter, _end, _flags, _k, _ret)\
for (; \
(_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, _flags), \
!((_ret) = bkey_err(_k)) && (_k).k; \
bch2_btree_iter_advance(&(_iter)))
/* new multiple iterator interface: */
void bch2_trans_updates_to_text(struct printbuf *, struct btree_trans *);
void bch2_btree_path_to_text(struct printbuf *, struct btree_path *);
void bch2_trans_paths_to_text(struct printbuf *, struct btree_trans *);
void bch2_dump_trans_updates(struct btree_trans *);
void bch2_dump_trans_paths_updates(struct btree_trans *);
void __bch2_trans_init(struct btree_trans *, struct bch_fs *, unsigned);
void bch2_trans_exit(struct btree_trans *);
extern const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR];
unsigned bch2_trans_get_fn_idx(const char *);
#define bch2_trans_init(_trans, _c, _nr_iters, _mem) \
do { \
static unsigned trans_fn_idx; \
\
if (unlikely(!trans_fn_idx)) \
trans_fn_idx = bch2_trans_get_fn_idx(__func__); \
\
__bch2_trans_init(_trans, _c, trans_fn_idx); \
} while (0)
void bch2_btree_trans_to_text(struct printbuf *, struct btree_trans *);
void bch2_fs_btree_iter_exit(struct bch_fs *);
int bch2_fs_btree_iter_init(struct bch_fs *);
#endif /* _BCACHEFS_BTREE_ITER_H */