From 85c675d0d09a45a135bddd15d7b385f8758c32fb Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 19:35:05 +0200 Subject: Adding upstream version 6.7.7. Signed-off-by: Daniel Baumann --- fs/bcachefs/nocow_locking.c | 144 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 144 insertions(+) create mode 100644 fs/bcachefs/nocow_locking.c (limited to 'fs/bcachefs/nocow_locking.c') diff --git a/fs/bcachefs/nocow_locking.c b/fs/bcachefs/nocow_locking.c new file mode 100644 index 000000000..3c21981a4 --- /dev/null +++ b/fs/bcachefs/nocow_locking.c @@ -0,0 +1,144 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "bcachefs.h" +#include "bkey_methods.h" +#include "nocow_locking.h" +#include "util.h" + +#include + +bool bch2_bucket_nocow_is_locked(struct bucket_nocow_lock_table *t, struct bpos bucket) +{ + u64 dev_bucket = bucket_to_u64(bucket); + struct nocow_lock_bucket *l = bucket_nocow_lock(t, dev_bucket); + unsigned i; + + for (i = 0; i < ARRAY_SIZE(l->b); i++) + if (l->b[i] == dev_bucket && atomic_read(&l->l[i])) + return true; + return false; +} + +#define sign(v) (v < 0 ? -1 : v > 0 ? 1 : 0) + +void bch2_bucket_nocow_unlock(struct bucket_nocow_lock_table *t, struct bpos bucket, int flags) +{ + u64 dev_bucket = bucket_to_u64(bucket); + struct nocow_lock_bucket *l = bucket_nocow_lock(t, dev_bucket); + int lock_val = flags ? 1 : -1; + unsigned i; + + for (i = 0; i < ARRAY_SIZE(l->b); i++) + if (l->b[i] == dev_bucket) { + int v = atomic_sub_return(lock_val, &l->l[i]); + + BUG_ON(v && sign(v) != lock_val); + if (!v) + closure_wake_up(&l->wait); + return; + } + + BUG(); +} + +bool __bch2_bucket_nocow_trylock(struct nocow_lock_bucket *l, + u64 dev_bucket, int flags) +{ + int v, lock_val = flags ? 1 : -1; + unsigned i; + + spin_lock(&l->lock); + + for (i = 0; i < ARRAY_SIZE(l->b); i++) + if (l->b[i] == dev_bucket) + goto got_entry; + + for (i = 0; i < ARRAY_SIZE(l->b); i++) + if (!atomic_read(&l->l[i])) { + l->b[i] = dev_bucket; + goto take_lock; + } +fail: + spin_unlock(&l->lock); + return false; +got_entry: + v = atomic_read(&l->l[i]); + if (lock_val > 0 ? v < 0 : v > 0) + goto fail; +take_lock: + v = atomic_read(&l->l[i]); + /* Overflow? */ + if (v && sign(v + lock_val) != sign(v)) + goto fail; + + atomic_add(lock_val, &l->l[i]); + spin_unlock(&l->lock); + return true; +} + +void __bch2_bucket_nocow_lock(struct bucket_nocow_lock_table *t, + struct nocow_lock_bucket *l, + u64 dev_bucket, int flags) +{ + if (!__bch2_bucket_nocow_trylock(l, dev_bucket, flags)) { + struct bch_fs *c = container_of(t, struct bch_fs, nocow_locks); + u64 start_time = local_clock(); + + __closure_wait_event(&l->wait, __bch2_bucket_nocow_trylock(l, dev_bucket, flags)); + bch2_time_stats_update(&c->times[BCH_TIME_nocow_lock_contended], start_time); + } +} + +void bch2_nocow_locks_to_text(struct printbuf *out, struct bucket_nocow_lock_table *t) + +{ + unsigned i, nr_zero = 0; + struct nocow_lock_bucket *l; + + for (l = t->l; l < t->l + ARRAY_SIZE(t->l); l++) { + unsigned v = 0; + + for (i = 0; i < ARRAY_SIZE(l->l); i++) + v |= atomic_read(&l->l[i]); + + if (!v) { + nr_zero++; + continue; + } + + if (nr_zero) + prt_printf(out, "(%u empty entries)\n", nr_zero); + nr_zero = 0; + + for (i = 0; i < ARRAY_SIZE(l->l); i++) { + int v = atomic_read(&l->l[i]); + if (v) { + bch2_bpos_to_text(out, u64_to_bucket(l->b[i])); + prt_printf(out, ": %s %u ", v < 0 ? "copy" : "update", abs(v)); + } + } + prt_newline(out); + } + + if (nr_zero) + prt_printf(out, "(%u empty entries)\n", nr_zero); +} + +void bch2_fs_nocow_locking_exit(struct bch_fs *c) +{ + struct bucket_nocow_lock_table *t = &c->nocow_locks; + + for (struct nocow_lock_bucket *l = t->l; l < t->l + ARRAY_SIZE(t->l); l++) + for (unsigned j = 0; j < ARRAY_SIZE(l->l); j++) + BUG_ON(atomic_read(&l->l[j])); +} + +int bch2_fs_nocow_locking_init(struct bch_fs *c) +{ + struct bucket_nocow_lock_table *t = &c->nocow_locks; + + for (struct nocow_lock_bucket *l = t->l; l < t->l + ARRAY_SIZE(t->l); l++) + spin_lock_init(&l->lock); + + return 0; +} -- cgit v1.2.3