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linux/fs/bcachefs/btree_gc.c
Kent Overstreet 4881fdb756 bcachefs: initial gc no longer needs to touch every node 
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2023-10-22 17:08:20 -04:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
* Copyright (C) 2014 Datera Inc.
*/
#include "bcachefs.h"
#include "alloc_background.h"
#include "alloc_foreground.h"
#include "bkey_methods.h"
#include "btree_locking.h"
#include "btree_update_interior.h"
#include "btree_io.h"
#include "btree_gc.h"
#include "buckets.h"
#include "clock.h"
#include "debug.h"
#include "ec.h"
#include "error.h"
#include "extents.h"
#include "journal.h"
#include "journal_io.h"
#include "keylist.h"
#include "move.h"
#include "replicas.h"
#include "super-io.h"
#include "trace.h"
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/preempt.h>
#include <linux/rcupdate.h>
#include <linux/sched/task.h>
static inline void __gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
{
preempt_disable();
write_seqcount_begin(&c->gc_pos_lock);
c->gc_pos = new_pos;
write_seqcount_end(&c->gc_pos_lock);
preempt_enable();
}
static inline void gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
{
BUG_ON(gc_pos_cmp(new_pos, c->gc_pos) <= 0);
__gc_pos_set(c, new_pos);
}
/* range_checks - for validating min/max pos of each btree node: */
struct range_checks {
struct range_level {
struct bpos min;
struct bpos max;
} l[BTREE_MAX_DEPTH];
unsigned depth;
};
static void btree_node_range_checks_init(struct range_checks *r, unsigned depth)
{
unsigned i;
for (i = 0; i < BTREE_MAX_DEPTH; i++)
r->l[i].min = r->l[i].max = POS_MIN;
r->depth = depth;
}
static void btree_node_range_checks(struct bch_fs *c, struct btree *b,
struct range_checks *r)
{
struct range_level *l = &r->l[b->level];
struct bpos expected_min = bkey_cmp(l->min, l->max)
? btree_type_successor(b->btree_id, l->max)
: l->max;
bch2_fs_inconsistent_on(bkey_cmp(b->data->min_key, expected_min), c,
"btree node has incorrect min key: %llu:%llu != %llu:%llu",
b->data->min_key.inode,
b->data->min_key.offset,
expected_min.inode,
expected_min.offset);
l->max = b->data->max_key;
if (b->level > r->depth) {
l = &r->l[b->level - 1];
bch2_fs_inconsistent_on(bkey_cmp(b->data->min_key, l->min), c,
"btree node min doesn't match min of child nodes: %llu:%llu != %llu:%llu",
b->data->min_key.inode,
b->data->min_key.offset,
l->min.inode,
l->min.offset);
bch2_fs_inconsistent_on(bkey_cmp(b->data->max_key, l->max), c,
"btree node max doesn't match max of child nodes: %llu:%llu != %llu:%llu",
b->data->max_key.inode,
b->data->max_key.offset,
l->max.inode,
l->max.offset);
if (bkey_cmp(b->data->max_key, POS_MAX))
l->min = l->max =
btree_type_successor(b->btree_id,
b->data->max_key);
}
}
/* marking of btree keys/nodes: */
static int bch2_gc_mark_key(struct bch_fs *c, struct bkey_s_c k,
u8 *max_stale, bool initial)
{
struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
const struct bch_extent_ptr *ptr;
unsigned flags =
BCH_BUCKET_MARK_GC|
(initial ? BCH_BUCKET_MARK_NOATOMIC : 0);
int ret = 0;
if (initial) {
BUG_ON(journal_seq_verify(c) &&
k.k->version.lo > journal_cur_seq(&c->journal));
if (k.k->version.lo > atomic64_read(&c->key_version))
atomic64_set(&c->key_version, k.k->version.lo);
if (test_bit(BCH_FS_REBUILD_REPLICAS, &c->flags) ||
fsck_err_on(!bch2_bkey_replicas_marked(c, k, false), c,
"superblock not marked as containing replicas (type %u)",
k.k->type)) {
ret = bch2_mark_bkey_replicas(c, k);
if (ret)
return ret;
}
bkey_for_each_ptr(ptrs, ptr) {
struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
struct bucket *g = PTR_BUCKET(ca, ptr, true);
struct bucket *g2 = PTR_BUCKET(ca, ptr, false);
if (mustfix_fsck_err_on(!g->gen_valid, c,
"found ptr with missing gen in alloc btree,\n"
"type %u gen %u",
k.k->type, ptr->gen)) {
g2->_mark.gen = g->_mark.gen = ptr->gen;
g2->_mark.dirty = g->_mark.dirty = true;
g2->gen_valid = g->gen_valid = true;
}
if (mustfix_fsck_err_on(gen_cmp(ptr->gen, g->mark.gen) > 0, c,
"%u ptr gen in the future: %u > %u",
k.k->type, ptr->gen, g->mark.gen)) {
g2->_mark.gen = g->_mark.gen = ptr->gen;
g2->_mark.dirty = g->_mark.dirty = true;
g2->gen_valid = g->gen_valid = true;
set_bit(BCH_FS_FIXED_GENS, &c->flags);
}
}
}
bkey_for_each_ptr(ptrs, ptr) {
struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
struct bucket *g = PTR_BUCKET(ca, ptr, true);
if (gen_after(g->oldest_gen, ptr->gen))
g->oldest_gen = ptr->gen;
*max_stale = max(*max_stale, ptr_stale(ca, ptr));
}
bch2_mark_key(c, k, true, k.k->size, NULL, 0, flags);
fsck_err:
return ret;
}
static int btree_gc_mark_node(struct bch_fs *c, struct btree *b,
u8 *max_stale, bool initial)
{
struct btree_node_iter iter;
struct bkey unpacked;
struct bkey_s_c k;
int ret = 0;
*max_stale = 0;
if (!btree_node_type_needs_gc(btree_node_type(b)))
return 0;
for_each_btree_node_key_unpack(b, k, &iter,
&unpacked) {
bch2_bkey_debugcheck(c, b, k);
ret = bch2_gc_mark_key(c, k, max_stale, initial);
if (ret)
break;
}
return ret;
}
static int bch2_gc_btree(struct bch_fs *c, enum btree_id btree_id,
bool initial, bool metadata_only)
{
struct btree_trans trans;
struct btree_iter *iter;
struct btree *b;
struct range_checks r;
unsigned depth = metadata_only ? 1
: expensive_debug_checks(c) ? 0
: !btree_node_type_needs_gc(btree_id) ? 1
: 0;
u8 max_stale;
int ret = 0;
bch2_trans_init(&trans, c);
gc_pos_set(c, gc_pos_btree(btree_id, POS_MIN, 0));
btree_node_range_checks_init(&r, depth);
__for_each_btree_node(&trans, iter, btree_id, POS_MIN,
0, depth, BTREE_ITER_PREFETCH, b) {
btree_node_range_checks(c, b, &r);
bch2_verify_btree_nr_keys(b);
gc_pos_set(c, gc_pos_btree_node(b));
ret = btree_gc_mark_node(c, b, &max_stale, initial);
if (ret)
break;
if (!initial) {
if (max_stale > 64)
bch2_btree_node_rewrite(c, iter,
b->data->keys.seq,
BTREE_INSERT_USE_RESERVE|
BTREE_INSERT_NOWAIT|
BTREE_INSERT_GC_LOCK_HELD);
else if (!btree_gc_rewrite_disabled(c) &&
(btree_gc_always_rewrite(c) || max_stale > 16))
bch2_btree_node_rewrite(c, iter,
b->data->keys.seq,
BTREE_INSERT_NOWAIT|
BTREE_INSERT_GC_LOCK_HELD);
}
bch2_trans_cond_resched(&trans);
}
ret = bch2_trans_exit(&trans) ?: ret;
if (ret)
return ret;
mutex_lock(&c->btree_root_lock);
b = c->btree_roots[btree_id].b;
if (!btree_node_fake(b))
ret = bch2_gc_mark_key(c, bkey_i_to_s_c(&b->key),
&max_stale, initial);
gc_pos_set(c, gc_pos_btree_root(b->btree_id));
mutex_unlock(&c->btree_root_lock);
return ret;
}
static inline int btree_id_gc_phase_cmp(enum btree_id l, enum btree_id r)
{
return (int) btree_id_to_gc_phase(l) -
(int) btree_id_to_gc_phase(r);
}
static int bch2_gc_btrees(struct bch_fs *c, struct list_head *journal,
bool initial, bool metadata_only)
{
enum btree_id ids[BTREE_ID_NR];
u8 max_stale;
unsigned i;
for (i = 0; i < BTREE_ID_NR; i++)
ids[i] = i;
bubble_sort(ids, BTREE_ID_NR, btree_id_gc_phase_cmp);
for (i = 0; i < BTREE_ID_NR; i++) {
enum btree_id id = ids[i];
enum btree_node_type type = __btree_node_type(0, id);
int ret = bch2_gc_btree(c, id, initial, metadata_only);
if (ret)
return ret;
if (journal && !metadata_only &&
btree_node_type_needs_gc(type)) {
struct bkey_i *k, *n;
struct jset_entry *j;
struct journal_replay *r;
int ret;
list_for_each_entry(r, journal, list)
for_each_jset_key(k, n, j, &r->j) {
if (type == __btree_node_type(j->level, j->btree_id)) {
ret = bch2_gc_mark_key(c,
bkey_i_to_s_c(k),
&max_stale, initial);
if (ret)
return ret;
}
}
}
}
return 0;
}
static void mark_metadata_sectors(struct bch_fs *c, struct bch_dev *ca,
u64 start, u64 end,
enum bch_data_type type,
unsigned flags)
{
u64 b = sector_to_bucket(ca, start);
do {
unsigned sectors =
min_t(u64, bucket_to_sector(ca, b + 1), end) - start;
bch2_mark_metadata_bucket(c, ca, b, type, sectors,
gc_phase(GC_PHASE_SB), flags);
b++;
start += sectors;
} while (start < end);
}
void bch2_mark_dev_superblock(struct bch_fs *c, struct bch_dev *ca,
unsigned flags)
{
struct bch_sb_layout *layout = &ca->disk_sb.sb->layout;
unsigned i;
u64 b;
/*
* This conditional is kind of gross, but we may be called from the
* device add path, before the new device has actually been added to the
* running filesystem:
*/
if (c) {
lockdep_assert_held(&c->sb_lock);
percpu_down_read(&c->mark_lock);
}
for (i = 0; i < layout->nr_superblocks; i++) {
u64 offset = le64_to_cpu(layout->sb_offset[i]);
if (offset == BCH_SB_SECTOR)
mark_metadata_sectors(c, ca, 0, BCH_SB_SECTOR,
BCH_DATA_SB, flags);
mark_metadata_sectors(c, ca, offset,
offset + (1 << layout->sb_max_size_bits),
BCH_DATA_SB, flags);
}
for (i = 0; i < ca->journal.nr; i++) {
b = ca->journal.buckets[i];
bch2_mark_metadata_bucket(c, ca, b, BCH_DATA_JOURNAL,
ca->mi.bucket_size,
gc_phase(GC_PHASE_SB), flags);
}
if (c)
percpu_up_read(&c->mark_lock);
}
static void bch2_mark_superblocks(struct bch_fs *c)
{
struct bch_dev *ca;
unsigned i;
mutex_lock(&c->sb_lock);
gc_pos_set(c, gc_phase(GC_PHASE_SB));
for_each_online_member(ca, c, i)
bch2_mark_dev_superblock(c, ca, BCH_BUCKET_MARK_GC);
mutex_unlock(&c->sb_lock);
}
/* Also see bch2_pending_btree_node_free_insert_done() */
static void bch2_mark_pending_btree_node_frees(struct bch_fs *c)
{
struct btree_update *as;
struct pending_btree_node_free *d;
mutex_lock(&c->btree_interior_update_lock);
gc_pos_set(c, gc_phase(GC_PHASE_PENDING_DELETE));
for_each_pending_btree_node_free(c, as, d)
if (d->index_update_done)
bch2_mark_key(c, bkey_i_to_s_c(&d->key),
true, 0, NULL, 0,
BCH_BUCKET_MARK_GC);
mutex_unlock(&c->btree_interior_update_lock);
}
static void bch2_mark_allocator_buckets(struct bch_fs *c)
{
struct bch_dev *ca;
struct open_bucket *ob;
size_t i, j, iter;
unsigned ci;
percpu_down_read(&c->mark_lock);
spin_lock(&c->freelist_lock);
gc_pos_set(c, gc_pos_alloc(c, NULL));
for_each_member_device(ca, c, ci) {
fifo_for_each_entry(i, &ca->free_inc, iter)
bch2_mark_alloc_bucket(c, ca, i, true,
gc_pos_alloc(c, NULL),
BCH_BUCKET_MARK_GC);
for (j = 0; j < RESERVE_NR; j++)
fifo_for_each_entry(i, &ca->free[j], iter)
bch2_mark_alloc_bucket(c, ca, i, true,
gc_pos_alloc(c, NULL),
BCH_BUCKET_MARK_GC);
}
spin_unlock(&c->freelist_lock);
for (ob = c->open_buckets;
ob < c->open_buckets + ARRAY_SIZE(c->open_buckets);
ob++) {
spin_lock(&ob->lock);
if (ob->valid) {
gc_pos_set(c, gc_pos_alloc(c, ob));
ca = bch_dev_bkey_exists(c, ob->ptr.dev);
bch2_mark_alloc_bucket(c, ca, PTR_BUCKET_NR(ca, &ob->ptr), true,
gc_pos_alloc(c, ob),
BCH_BUCKET_MARK_GC);
}
spin_unlock(&ob->lock);
}
percpu_up_read(&c->mark_lock);
}
static void bch2_gc_free(struct bch_fs *c)
{
struct bch_dev *ca;
unsigned i;
genradix_free(&c->stripes[1]);
for_each_member_device(ca, c, i) {
kvpfree(rcu_dereference_protected(ca->buckets[1], 1),
sizeof(struct bucket_array) +
ca->mi.nbuckets * sizeof(struct bucket));
ca->buckets[1] = NULL;
free_percpu(ca->usage[1]);
ca->usage[1] = NULL;
}
free_percpu(c->usage[1]);
c->usage[1] = NULL;
}
static int bch2_gc_done(struct bch_fs *c,
bool initial, bool metadata_only)
{
struct bch_dev *ca;
bool verify = !metadata_only &&
(!initial ||
(c->sb.compat & (1ULL << BCH_COMPAT_FEAT_ALLOC_INFO)));
unsigned i;
int ret = 0;
#define copy_field(_f, _msg, ...) \
if (dst->_f != src->_f) { \
if (verify) \
fsck_err(c, _msg ": got %llu, should be %llu" \
, ##__VA_ARGS__, dst->_f, src->_f); \
dst->_f = src->_f; \
}
#define copy_stripe_field(_f, _msg, ...) \
if (dst->_f != src->_f) { \
if (verify) \
fsck_err(c, "stripe %zu has wrong "_msg \
": got %u, should be %u", \
dst_iter.pos, ##__VA_ARGS__, \
dst->_f, src->_f); \
dst->_f = src->_f; \
dst->dirty = true; \
}
#define copy_bucket_field(_f) \
if (dst->b[b].mark._f != src->b[b].mark._f) { \
if (verify) \
fsck_err(c, "dev %u bucket %zu has wrong " #_f \
": got %u, should be %u", i, b, \
dst->b[b].mark._f, src->b[b].mark._f); \
dst->b[b]._mark._f = src->b[b].mark._f; \
dst->b[b]._mark.dirty = true; \
}
#define copy_dev_field(_f, _msg, ...) \
copy_field(_f, "dev %u has wrong " _msg, i, ##__VA_ARGS__)
#define copy_fs_field(_f, _msg, ...) \
copy_field(_f, "fs has wrong " _msg, ##__VA_ARGS__)
if (!metadata_only) {
struct genradix_iter dst_iter = genradix_iter_init(&c->stripes[0], 0);
struct genradix_iter src_iter = genradix_iter_init(&c->stripes[1], 0);
struct stripe *dst, *src;
unsigned i;
c->ec_stripes_heap.used = 0;
while ((dst = genradix_iter_peek(&dst_iter, &c->stripes[0])) &&
(src = genradix_iter_peek(&src_iter, &c->stripes[1]))) {
BUG_ON(src_iter.pos != dst_iter.pos);
copy_stripe_field(alive, "alive");
copy_stripe_field(sectors, "sectors");
copy_stripe_field(algorithm, "algorithm");
copy_stripe_field(nr_blocks, "nr_blocks");
copy_stripe_field(nr_redundant, "nr_redundant");
copy_stripe_field(blocks_nonempty,
"blocks_nonempty");
for (i = 0; i < ARRAY_SIZE(dst->block_sectors); i++)
copy_stripe_field(block_sectors[i],
"block_sectors[%u]", i);
if (dst->alive)
bch2_stripes_heap_insert(c, dst, dst_iter.pos);
genradix_iter_advance(&dst_iter, &c->stripes[0]);
genradix_iter_advance(&src_iter, &c->stripes[1]);
}
}
for_each_member_device(ca, c, i) {
struct bucket_array *dst = __bucket_array(ca, 0);
struct bucket_array *src = __bucket_array(ca, 1);
size_t b;
for (b = 0; b < src->nbuckets; b++) {
copy_bucket_field(gen);
copy_bucket_field(data_type);
copy_bucket_field(owned_by_allocator);
copy_bucket_field(stripe);
copy_bucket_field(dirty_sectors);
copy_bucket_field(cached_sectors);
if (dst->b[b].oldest_gen != src->b[b].oldest_gen) {
dst->b[b].oldest_gen = src->b[b].oldest_gen;
dst->b[b]._mark.dirty = true;
}
}
};
bch2_dev_usage_from_buckets(c);
{
unsigned nr = fs_usage_u64s(c);
struct bch_fs_usage *dst = (void *)
bch2_acc_percpu_u64s((void *) c->usage[0], nr);
struct bch_fs_usage *src = (void *)
bch2_acc_percpu_u64s((void *) c->usage[1], nr);
copy_fs_field(hidden, "hidden");
copy_fs_field(btree, "btree");
if (!metadata_only) {
copy_fs_field(data, "data");
copy_fs_field(cached, "cached");
copy_fs_field(reserved, "reserved");
copy_fs_field(nr_inodes,"nr_inodes");
for (i = 0; i < BCH_REPLICAS_MAX; i++)
copy_fs_field(persistent_reserved[i],
"persistent_reserved[%i]", i);
}
for (i = 0; i < c->replicas.nr; i++) {
struct bch_replicas_entry *e =
cpu_replicas_entry(&c->replicas, i);
char buf[80];
if (metadata_only &&
(e->data_type == BCH_DATA_USER ||
e->data_type == BCH_DATA_CACHED))
continue;
bch2_replicas_entry_to_text(&PBUF(buf), e);
copy_fs_field(replicas[i], "%s", buf);
}
}
#undef copy_fs_field
#undef copy_dev_field
#undef copy_bucket_field
#undef copy_stripe_field
#undef copy_field
fsck_err:
return ret;
}
static int bch2_gc_start(struct bch_fs *c,
bool metadata_only)
{
struct bch_dev *ca;
unsigned i;
/*
* indicate to stripe code that we need to allocate for the gc stripes
* radix tree, too
*/
gc_pos_set(c, gc_phase(GC_PHASE_START));
BUG_ON(c->usage[1]);
c->usage[1] = __alloc_percpu_gfp(fs_usage_u64s(c) * sizeof(u64),
sizeof(u64), GFP_KERNEL);
if (!c->usage[1])
return -ENOMEM;
for_each_member_device(ca, c, i) {
BUG_ON(ca->buckets[1]);
BUG_ON(ca->usage[1]);
ca->buckets[1] = kvpmalloc(sizeof(struct bucket_array) +
ca->mi.nbuckets * sizeof(struct bucket),
GFP_KERNEL|__GFP_ZERO);
if (!ca->buckets[1]) {
percpu_ref_put(&ca->ref);
return -ENOMEM;
}
ca->usage[1] = alloc_percpu(struct bch_dev_usage);
if (!ca->usage[1]) {
percpu_ref_put(&ca->ref);
return -ENOMEM;
}
}
for_each_member_device(ca, c, i) {
struct bucket_array *dst = __bucket_array(ca, 1);
struct bucket_array *src = __bucket_array(ca, 0);
size_t b;
dst->first_bucket = src->first_bucket;
dst->nbuckets = src->nbuckets;
for (b = 0; b < src->nbuckets; b++) {
struct bucket *d = &dst->b[b];
struct bucket *s = &src->b[b];
d->_mark.gen = dst->b[b].oldest_gen = s->mark.gen;
d->gen_valid = s->gen_valid;
if (metadata_only &&
(s->mark.data_type == BCH_DATA_USER ||
s->mark.data_type == BCH_DATA_CACHED)) {
d->_mark = s->mark;
d->_mark.owned_by_allocator = 0;
}
}
};
return bch2_ec_mem_alloc(c, true);
}
/**
* bch2_gc - walk _all_ references to buckets, and recompute them:
*
* Order matters here:
* - Concurrent GC relies on the fact that we have a total ordering for
* everything that GC walks - see gc_will_visit_node(),
* gc_will_visit_root()
*
* - also, references move around in the course of index updates and
* various other crap: everything needs to agree on the ordering
* references are allowed to move around in - e.g., we're allowed to
* start with a reference owned by an open_bucket (the allocator) and
* move it to the btree, but not the reverse.
*
* This is necessary to ensure that gc doesn't miss references that
* move around - if references move backwards in the ordering GC
* uses, GC could skip past them
*/
int bch2_gc(struct bch_fs *c, struct list_head *journal,
bool initial, bool metadata_only)
{
struct bch_dev *ca;
u64 start_time = local_clock();
unsigned i, iter = 0;
int ret;
trace_gc_start(c);
down_write(&c->gc_lock);
again:
percpu_down_write(&c->mark_lock);
ret = bch2_gc_start(c, metadata_only);
percpu_up_write(&c->mark_lock);
if (ret)
goto out;
bch2_mark_superblocks(c);
ret = bch2_gc_btrees(c, journal, initial, metadata_only);
if (ret)
goto out;
bch2_mark_pending_btree_node_frees(c);
bch2_mark_allocator_buckets(c);
c->gc_count++;
out:
if (!ret &&
(test_bit(BCH_FS_FIXED_GENS, &c->flags) ||
(!iter && test_restart_gc(c)))) {
/*
* XXX: make sure gens we fixed got saved
*/
if (iter++ <= 2) {
bch_info(c, "Fixed gens, restarting mark and sweep:");
clear_bit(BCH_FS_FIXED_GENS, &c->flags);
__gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
percpu_down_write(&c->mark_lock);
bch2_gc_free(c);
percpu_up_write(&c->mark_lock);
goto again;
}
bch_info(c, "Unable to fix bucket gens, looping");
ret = -EINVAL;
}
percpu_down_write(&c->mark_lock);
if (!ret)
ret = bch2_gc_done(c, initial, metadata_only);
/* Indicates that gc is no longer in progress: */
__gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
bch2_gc_free(c);
percpu_up_write(&c->mark_lock);
up_write(&c->gc_lock);
trace_gc_end(c);
bch2_time_stats_update(&c->times[BCH_TIME_btree_gc], start_time);
/*
* Wake up allocator in case it was waiting for buckets
* because of not being able to inc gens
*/
for_each_member_device(ca, c, i)
bch2_wake_allocator(ca);
/*
* At startup, allocations can happen directly instead of via the
* allocator thread - issue wakeup in case they blocked on gc_lock:
*/
closure_wake_up(&c->freelist_wait);
return ret;
}
/* Btree coalescing */
static void recalc_packed_keys(struct btree *b)
{
struct bset *i = btree_bset_first(b);
struct bkey_packed *k;
memset(&b->nr, 0, sizeof(b->nr));
BUG_ON(b->nsets != 1);
vstruct_for_each(i, k)
btree_keys_account_key_add(&b->nr, 0, k);
}
static void bch2_coalesce_nodes(struct bch_fs *c, struct btree_iter *iter,
struct btree *old_nodes[GC_MERGE_NODES])
{
struct btree *parent = btree_node_parent(iter, old_nodes[0]);
unsigned i, nr_old_nodes, nr_new_nodes, u64s = 0;
unsigned blocks = btree_blocks(c) * 2 / 3;
struct btree *new_nodes[GC_MERGE_NODES];
struct btree_update *as;
struct keylist keylist;
struct bkey_format_state format_state;
struct bkey_format new_format;
memset(new_nodes, 0, sizeof(new_nodes));
bch2_keylist_init(&keylist, NULL);
/* Count keys that are not deleted */
for (i = 0; i < GC_MERGE_NODES && old_nodes[i]; i++)
u64s += old_nodes[i]->nr.live_u64s;
nr_old_nodes = nr_new_nodes = i;
/* Check if all keys in @old_nodes could fit in one fewer node */
if (nr_old_nodes <= 1 ||
__vstruct_blocks(struct btree_node, c->block_bits,
DIV_ROUND_UP(u64s, nr_old_nodes - 1)) > blocks)
return;
/* Find a format that all keys in @old_nodes can pack into */
bch2_bkey_format_init(&format_state);
for (i = 0; i < nr_old_nodes; i++)
__bch2_btree_calc_format(&format_state, old_nodes[i]);
new_format = bch2_bkey_format_done(&format_state);
/* Check if repacking would make any nodes too big to fit */
for (i = 0; i < nr_old_nodes; i++)
if (!bch2_btree_node_format_fits(c, old_nodes[i], &new_format)) {
trace_btree_gc_coalesce_fail(c,
BTREE_GC_COALESCE_FAIL_FORMAT_FITS);
return;
}
if (bch2_keylist_realloc(&keylist, NULL, 0,
(BKEY_U64s + BKEY_EXTENT_U64s_MAX) * nr_old_nodes)) {
trace_btree_gc_coalesce_fail(c,
BTREE_GC_COALESCE_FAIL_KEYLIST_REALLOC);
return;
}
as = bch2_btree_update_start(c, iter->btree_id,
btree_update_reserve_required(c, parent) + nr_old_nodes,
BTREE_INSERT_NOFAIL|
BTREE_INSERT_USE_RESERVE,
NULL);
if (IS_ERR(as)) {
trace_btree_gc_coalesce_fail(c,
BTREE_GC_COALESCE_FAIL_RESERVE_GET);
bch2_keylist_free(&keylist, NULL);
return;
}
trace_btree_gc_coalesce(c, old_nodes[0]);
for (i = 0; i < nr_old_nodes; i++)
bch2_btree_interior_update_will_free_node(as, old_nodes[i]);
/* Repack everything with @new_format and sort down to one bset */
for (i = 0; i < nr_old_nodes; i++)
new_nodes[i] =
__bch2_btree_node_alloc_replacement(as, old_nodes[i],
new_format);
/*
* Conceptually we concatenate the nodes together and slice them
* up at different boundaries.
*/
for (i = nr_new_nodes - 1; i > 0; --i) {
struct btree *n1 = new_nodes[i];
struct btree *n2 = new_nodes[i - 1];
struct bset *s1 = btree_bset_first(n1);
struct bset *s2 = btree_bset_first(n2);
struct bkey_packed *k, *last = NULL;
/* Calculate how many keys from @n2 we could fit inside @n1 */
u64s = 0;
for (k = s2->start;
k < vstruct_last(s2) &&
vstruct_blocks_plus(n1->data, c->block_bits,
u64s + k->u64s) <= blocks;
k = bkey_next(k)) {
last = k;
u64s += k->u64s;
}
if (u64s == le16_to_cpu(s2->u64s)) {
/* n2 fits entirely in n1 */
n1->key.k.p = n1->data->max_key = n2->data->max_key;
memcpy_u64s(vstruct_last(s1),
s2->start,
le16_to_cpu(s2->u64s));
le16_add_cpu(&s1->u64s, le16_to_cpu(s2->u64s));
set_btree_bset_end(n1, n1->set);
six_unlock_write(&n2->lock);
bch2_btree_node_free_never_inserted(c, n2);
six_unlock_intent(&n2->lock);
memmove(new_nodes + i - 1,
new_nodes + i,
sizeof(new_nodes[0]) * (nr_new_nodes - i));
new_nodes[--nr_new_nodes] = NULL;
} else if (u64s) {
/* move part of n2 into n1 */
n1->key.k.p = n1->data->max_key =
bkey_unpack_pos(n1, last);
n2->data->min_key =
btree_type_successor(iter->btree_id,
n1->data->max_key);
memcpy_u64s(vstruct_last(s1),
s2->start, u64s);
le16_add_cpu(&s1->u64s, u64s);
memmove(s2->start,
vstruct_idx(s2, u64s),
(le16_to_cpu(s2->u64s) - u64s) * sizeof(u64));
s2->u64s = cpu_to_le16(le16_to_cpu(s2->u64s) - u64s);
set_btree_bset_end(n1, n1->set);
set_btree_bset_end(n2, n2->set);
}
}
for (i = 0; i < nr_new_nodes; i++) {
struct btree *n = new_nodes[i];
recalc_packed_keys(n);
btree_node_reset_sib_u64s(n);
bch2_btree_build_aux_trees(n);
six_unlock_write(&n->lock);
bch2_btree_node_write(c, n, SIX_LOCK_intent);
}
/*
* The keys for the old nodes get deleted. We don't want to insert keys
* that compare equal to the keys for the new nodes we'll also be
* inserting - we can't because keys on a keylist must be strictly
* greater than the previous keys, and we also don't need to since the
* key for the new node will serve the same purpose (overwriting the key
* for the old node).
*/
for (i = 0; i < nr_old_nodes; i++) {
struct bkey_i delete;
unsigned j;
for (j = 0; j < nr_new_nodes; j++)
if (!bkey_cmp(old_nodes[i]->key.k.p,
new_nodes[j]->key.k.p))
goto next;
bkey_init(&delete.k);
delete.k.p = old_nodes[i]->key.k.p;
bch2_keylist_add_in_order(&keylist, &delete);
next:
i = i;
}
/*
* Keys for the new nodes get inserted: bch2_btree_insert_keys() only
* does the lookup once and thus expects the keys to be in sorted order
* so we have to make sure the new keys are correctly ordered with
* respect to the deleted keys added in the previous loop
*/
for (i = 0; i < nr_new_nodes; i++)
bch2_keylist_add_in_order(&keylist, &new_nodes[i]->key);
/* Insert the newly coalesced nodes */
bch2_btree_insert_node(as, parent, iter, &keylist, 0);
BUG_ON(!bch2_keylist_empty(&keylist));
BUG_ON(iter->l[old_nodes[0]->level].b != old_nodes[0]);
bch2_btree_iter_node_replace(iter, new_nodes[0]);
for (i = 0; i < nr_new_nodes; i++)
bch2_open_buckets_put(c, &new_nodes[i]->ob);
/* Free the old nodes and update our sliding window */
for (i = 0; i < nr_old_nodes; i++) {
bch2_btree_node_free_inmem(c, old_nodes[i], iter);
/*
* the index update might have triggered a split, in which case
* the nodes we coalesced - the new nodes we just created -
* might not be sibling nodes anymore - don't add them to the
* sliding window (except the first):
*/
if (!i) {
old_nodes[i] = new_nodes[i];
} else {
old_nodes[i] = NULL;
if (new_nodes[i])
six_unlock_intent(&new_nodes[i]->lock);
}
}
bch2_btree_update_done(as);
bch2_keylist_free(&keylist, NULL);
}
static int bch2_coalesce_btree(struct bch_fs *c, enum btree_id btree_id)
{
struct btree_trans trans;
struct btree_iter *iter;
struct btree *b;
bool kthread = (current->flags & PF_KTHREAD) != 0;
unsigned i;
/* Sliding window of adjacent btree nodes */
struct btree *merge[GC_MERGE_NODES];
u32 lock_seq[GC_MERGE_NODES];
bch2_trans_init(&trans, c);
/*
* XXX: We don't have a good way of positively matching on sibling nodes
* that have the same parent - this code works by handling the cases
* where they might not have the same parent, and is thus fragile. Ugh.
*
* Perhaps redo this to use multiple linked iterators?
*/
memset(merge, 0, sizeof(merge));
__for_each_btree_node(&trans, iter, btree_id, POS_MIN,
BTREE_MAX_DEPTH, 0,
BTREE_ITER_PREFETCH, b) {
memmove(merge + 1, merge,
sizeof(merge) - sizeof(merge[0]));
memmove(lock_seq + 1, lock_seq,
sizeof(lock_seq) - sizeof(lock_seq[0]));
merge[0] = b;
for (i = 1; i < GC_MERGE_NODES; i++) {
if (!merge[i] ||
!six_relock_intent(&merge[i]->lock, lock_seq[i]))
break;
if (merge[i]->level != merge[0]->level) {
six_unlock_intent(&merge[i]->lock);
break;
}
}
memset(merge + i, 0, (GC_MERGE_NODES - i) * sizeof(merge[0]));
bch2_coalesce_nodes(c, iter, merge);
for (i = 1; i < GC_MERGE_NODES && merge[i]; i++) {
lock_seq[i] = merge[i]->lock.state.seq;
six_unlock_intent(&merge[i]->lock);
}
lock_seq[0] = merge[0]->lock.state.seq;
if (kthread && kthread_should_stop()) {
bch2_trans_exit(&trans);
return -ESHUTDOWN;
}
bch2_trans_cond_resched(&trans);
/*
* If the parent node wasn't relocked, it might have been split
* and the nodes in our sliding window might not have the same
* parent anymore - blow away the sliding window:
*/
if (btree_iter_node(iter, iter->level + 1) &&
!btree_node_intent_locked(iter, iter->level + 1))
memset(merge + 1, 0,
(GC_MERGE_NODES - 1) * sizeof(merge[0]));
}
return bch2_trans_exit(&trans);
}
/**
* bch_coalesce - coalesce adjacent nodes with low occupancy
*/
void bch2_coalesce(struct bch_fs *c)
{
enum btree_id id;
down_read(&c->gc_lock);
trace_gc_coalesce_start(c);
for (id = 0; id < BTREE_ID_NR; id++) {
int ret = c->btree_roots[id].b
? bch2_coalesce_btree(c, id)
: 0;
if (ret) {
if (ret != -ESHUTDOWN)
bch_err(c, "btree coalescing failed: %d", ret);
return;
}
}
trace_gc_coalesce_end(c);
up_read(&c->gc_lock);
}
static int bch2_gc_thread(void *arg)
{
struct bch_fs *c = arg;
struct io_clock *clock = &c->io_clock[WRITE];
unsigned long last = atomic_long_read(&clock->now);
unsigned last_kick = atomic_read(&c->kick_gc);
int ret;
set_freezable();
while (1) {
while (1) {
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
return 0;
}
if (atomic_read(&c->kick_gc) != last_kick)
break;
if (c->btree_gc_periodic) {
unsigned long next = last + c->capacity / 16;
if (atomic_long_read(&clock->now) >= next)
break;
bch2_io_clock_schedule_timeout(clock, next);
} else {
schedule();
}
try_to_freeze();
}
__set_current_state(TASK_RUNNING);
last = atomic_long_read(&clock->now);
last_kick = atomic_read(&c->kick_gc);
ret = bch2_gc(c, NULL, false, false);
if (ret)
bch_err(c, "btree gc failed: %i", ret);
debug_check_no_locks_held();
}
return 0;
}
void bch2_gc_thread_stop(struct bch_fs *c)
{
struct task_struct *p;
p = c->gc_thread;
c->gc_thread = NULL;
if (p) {
kthread_stop(p);
put_task_struct(p);
}
}
int bch2_gc_thread_start(struct bch_fs *c)
{
struct task_struct *p;
BUG_ON(c->gc_thread);
p = kthread_create(bch2_gc_thread, c, "bch_gc");
if (IS_ERR(p))
return PTR_ERR(p);
get_task_struct(p);
c->gc_thread = p;
wake_up_process(p);
return 0;
}
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