linux-stable/fs/bcachefs/journal_reclaim.h
Kent Overstreet d483dd17e2 bcachefs: Fix race between journal_seq_copy() and journal_seq_drop()
In bch2_btree_interior_update_will_free_node, we copy the journal pins
from outstanding writes on the btree node we're about to free. But, this
can race with the writes completing, and dropping their journal pins.

To guard against this, just use READ_ONCE() in bch2_journal_pin_copy().

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:50 -04:00

88 lines
2.4 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _BCACHEFS_JOURNAL_RECLAIM_H
#define _BCACHEFS_JOURNAL_RECLAIM_H
#define JOURNAL_PIN (32 * 1024)
static inline void journal_reclaim_kick(struct journal *j)
{
struct task_struct *p = READ_ONCE(j->reclaim_thread);
if (p && !j->reclaim_kicked) {
j->reclaim_kicked = true;
if (p)
wake_up_process(p);
}
}
unsigned bch2_journal_dev_buckets_available(struct journal *,
struct journal_device *,
enum journal_space_from);
void bch2_journal_space_available(struct journal *);
static inline bool journal_pin_active(struct journal_entry_pin *pin)
{
return pin->seq != 0;
}
static inline struct journal_entry_pin_list *
journal_seq_pin(struct journal *j, u64 seq)
{
EBUG_ON(seq < j->pin.front || seq >= j->pin.back);
return &j->pin.data[seq & j->pin.mask];
}
void __bch2_journal_pin_put(struct journal *, u64);
void bch2_journal_pin_put(struct journal *, u64);
void bch2_journal_pin_drop(struct journal *, struct journal_entry_pin *);
void bch2_journal_pin_set(struct journal *, u64, struct journal_entry_pin *,
journal_pin_flush_fn);
static inline void bch2_journal_pin_add(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
if (unlikely(!journal_pin_active(pin) || pin->seq > seq))
bch2_journal_pin_set(j, seq, pin, flush_fn);
}
static inline void bch2_journal_pin_copy(struct journal *j,
struct journal_entry_pin *dst,
struct journal_entry_pin *src,
journal_pin_flush_fn flush_fn)
{
/* Guard against racing with journal_pin_drop(src): */
u64 seq = READ_ONCE(src->seq);
if (seq)
bch2_journal_pin_add(j, seq, dst, flush_fn);
}
static inline void bch2_journal_pin_update(struct journal *j, u64 seq,
struct journal_entry_pin *pin,
journal_pin_flush_fn flush_fn)
{
if (unlikely(!journal_pin_active(pin) || pin->seq < seq))
bch2_journal_pin_set(j, seq, pin, flush_fn);
}
void bch2_journal_pin_flush(struct journal *, struct journal_entry_pin *);
void bch2_journal_do_discards(struct journal *);
int bch2_journal_reclaim(struct journal *);
void bch2_journal_reclaim_stop(struct journal *);
int bch2_journal_reclaim_start(struct journal *);
bool bch2_journal_flush_pins(struct journal *, u64);
static inline bool bch2_journal_flush_all_pins(struct journal *j)
{
return bch2_journal_flush_pins(j, U64_MAX);
}
int bch2_journal_flush_device_pins(struct journal *, int);
#endif /* _BCACHEFS_JOURNAL_RECLAIM_H */