diff options
Diffstat (limited to 'fs/bcachefs/alloc_foreground.c')
| -rw-r--r-- | fs/bcachefs/alloc_foreground.c | 740 |
1 files changed, 740 insertions, 0 deletions
diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c new file mode 100644 index 000000000000..9fba3e414c62 --- /dev/null +++ b/fs/bcachefs/alloc_foreground.c @@ -0,0 +1,740 @@ +/* + * Primary bucket allocation code + * + * Copyright 2012 Google, Inc. + * + * Allocation in bcache is done in terms of buckets: + * + * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in + * btree pointers - they must match for the pointer to be considered valid. + * + * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a + * bucket simply by incrementing its gen. + * + * The gens (along with the priorities; it's really the gens are important but + * the code is named as if it's the priorities) are written in an arbitrary list + * of buckets on disk, with a pointer to them in the journal header. + * + * When we invalidate a bucket, we have to write its new gen to disk and wait + * for that write to complete before we use it - otherwise after a crash we + * could have pointers that appeared to be good but pointed to data that had + * been overwritten. + * + * Since the gens and priorities are all stored contiguously on disk, we can + * batch this up: We fill up the free_inc list with freshly invalidated buckets, + * call prio_write(), and when prio_write() finishes we pull buckets off the + * free_inc list and optionally discard them. + * + * free_inc isn't the only freelist - if it was, we'd often have to sleep while + * priorities and gens were being written before we could allocate. c->free is a + * smaller freelist, and buckets on that list are always ready to be used. + * + * If we've got discards enabled, that happens when a bucket moves from the + * free_inc list to the free list. + * + * It's important to ensure that gens don't wrap around - with respect to + * either the oldest gen in the btree or the gen on disk. This is quite + * difficult to do in practice, but we explicitly guard against it anyways - if + * a bucket is in danger of wrapping around we simply skip invalidating it that + * time around, and we garbage collect or rewrite the priorities sooner than we + * would have otherwise. + * + * bch2_bucket_alloc() allocates a single bucket from a specific device. + * + * bch2_bucket_alloc_set() allocates one or more buckets from different devices + * in a given filesystem. + * + * invalidate_buckets() drives all the processes described above. It's called + * from bch2_bucket_alloc() and a few other places that need to make sure free + * buckets are ready. + * + * invalidate_buckets_(lru|fifo)() find buckets that are available to be + * invalidated, and then invalidate them and stick them on the free_inc list - + * in either lru or fifo order. + */ + +#include "bcachefs.h" +#include "alloc_background.h" +#include "alloc_foreground.h" +#include "btree_gc.h" +#include "buckets.h" +#include "clock.h" +#include "debug.h" +#include "disk_groups.h" +#include "io.h" + +#include <linux/math64.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> +#include <trace/events/bcachefs.h> + +enum bucket_alloc_ret { + ALLOC_SUCCESS = 0, + OPEN_BUCKETS_EMPTY = -1, + FREELIST_EMPTY = -2, /* Allocator thread not keeping up */ + NO_DEVICES = -3, /* -EROFS */ +}; + +/* + * Open buckets represent a bucket that's currently being allocated from. They + * serve two purposes: + * + * - They track buckets that have been partially allocated, allowing for + * sub-bucket sized allocations - they're used by the sector allocator below + * + * - They provide a reference to the buckets they own that mark and sweep GC + * can find, until the new allocation has a pointer to it inserted into the + * btree + * + * When allocating some space with the sector allocator, the allocation comes + * with a reference to an open bucket - the caller is required to put that + * reference _after_ doing the index update that makes its allocation reachable. + */ + +void __bch2_open_bucket_put(struct bch_fs *c, struct open_bucket *ob) +{ + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + percpu_down_read_preempt_disable(&c->usage_lock); + spin_lock(&ob->lock); + + bch2_mark_alloc_bucket(c, ca, PTR_BUCKET_NR(ca, &ob->ptr), + false, gc_pos_alloc(c, ob), 0); + ob->valid = false; + + spin_unlock(&ob->lock); + percpu_up_read_preempt_enable(&c->usage_lock); + + spin_lock(&c->freelist_lock); + ob->freelist = c->open_buckets_freelist; + c->open_buckets_freelist = ob - c->open_buckets; + c->open_buckets_nr_free++; + spin_unlock(&c->freelist_lock); + + closure_wake_up(&c->open_buckets_wait); +} + +static struct open_bucket *bch2_open_bucket_alloc(struct bch_fs *c) +{ + struct open_bucket *ob; + + BUG_ON(!c->open_buckets_freelist || !c->open_buckets_nr_free); + + ob = c->open_buckets + c->open_buckets_freelist; + c->open_buckets_freelist = ob->freelist; + atomic_set(&ob->pin, 1); + + c->open_buckets_nr_free--; + return ob; +} + +/* _only_ for allocating the journal on a new device: */ +long bch2_bucket_alloc_new_fs(struct bch_dev *ca) +{ + struct bucket_array *buckets; + ssize_t b; + + rcu_read_lock(); + buckets = bucket_array(ca); + + for (b = ca->mi.first_bucket; b < ca->mi.nbuckets; b++) + if (is_available_bucket(buckets->b[b].mark)) + goto success; + b = -1; +success: + rcu_read_unlock(); + return b; +} + +static inline unsigned open_buckets_reserved(enum alloc_reserve reserve) +{ + switch (reserve) { + case RESERVE_ALLOC: + return 0; + case RESERVE_BTREE: + return BTREE_NODE_RESERVE / 2; + default: + return BTREE_NODE_RESERVE; + } +} + +/** + * bch_bucket_alloc - allocate a single bucket from a specific device + * + * Returns index of bucket on success, 0 on failure + * */ +int bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca, + enum alloc_reserve reserve, + bool may_alloc_partial, + struct closure *cl) +{ + struct bucket_array *buckets; + struct open_bucket *ob; + long bucket; + + spin_lock(&c->freelist_lock); + + if (may_alloc_partial && + ca->open_buckets_partial_nr) { + int ret = ca->open_buckets_partial[--ca->open_buckets_partial_nr]; + c->open_buckets[ret].on_partial_list = false; + spin_unlock(&c->freelist_lock); + return ret; + } + + if (unlikely(c->open_buckets_nr_free <= open_buckets_reserved(reserve))) { + if (cl) + closure_wait(&c->open_buckets_wait, cl); + spin_unlock(&c->freelist_lock); + trace_open_bucket_alloc_fail(ca, reserve); + return OPEN_BUCKETS_EMPTY; + } + + if (likely(fifo_pop(&ca->free[RESERVE_NONE], bucket))) + goto out; + + switch (reserve) { + case RESERVE_ALLOC: + if (fifo_pop(&ca->free[RESERVE_BTREE], bucket)) + goto out; + break; + case RESERVE_BTREE: + if (fifo_used(&ca->free[RESERVE_BTREE]) * 2 >= + ca->free[RESERVE_BTREE].size && + fifo_pop(&ca->free[RESERVE_BTREE], bucket)) + goto out; + break; + case RESERVE_MOVINGGC: + if (fifo_pop(&ca->free[RESERVE_MOVINGGC], bucket)) + goto out; + break; + default: + break; + } + + if (cl) + closure_wait(&c->freelist_wait, cl); + + spin_unlock(&c->freelist_lock); + + trace_bucket_alloc_fail(ca, reserve); + return FREELIST_EMPTY; +out: + verify_not_on_freelist(c, ca, bucket); + + ob = bch2_open_bucket_alloc(c); + + spin_lock(&ob->lock); + buckets = bucket_array(ca); + + ob->valid = true; + ob->sectors_free = ca->mi.bucket_size; + ob->ptr = (struct bch_extent_ptr) { + .gen = buckets->b[bucket].mark.gen, + .offset = bucket_to_sector(ca, bucket), + .dev = ca->dev_idx, + }; + + bucket_io_clock_reset(c, ca, bucket, READ); + bucket_io_clock_reset(c, ca, bucket, WRITE); + spin_unlock(&ob->lock); + + spin_unlock(&c->freelist_lock); + + bch2_wake_allocator(ca); + + trace_bucket_alloc(ca, reserve); + return ob - c->open_buckets; +} + +static int __dev_alloc_cmp(struct write_point *wp, + unsigned l, unsigned r) +{ + return ((wp->next_alloc[l] > wp->next_alloc[r]) - + (wp->next_alloc[l] < wp->next_alloc[r])); +} + +#define dev_alloc_cmp(l, r) __dev_alloc_cmp(wp, l, r) + +struct dev_alloc_list bch2_wp_alloc_list(struct bch_fs *c, + struct write_point *wp, + struct bch_devs_mask *devs) +{ + struct dev_alloc_list ret = { .nr = 0 }; + struct bch_dev *ca; + unsigned i; + + for_each_member_device_rcu(ca, c, i, devs) + ret.devs[ret.nr++] = i; + + bubble_sort(ret.devs, ret.nr, dev_alloc_cmp); + return ret; +} + +void bch2_wp_rescale(struct bch_fs *c, struct bch_dev *ca, + struct write_point *wp) +{ + u64 *v = wp->next_alloc + ca->dev_idx; + u64 free_space = dev_buckets_free(c, ca); + u64 free_space_inv = free_space + ? div64_u64(1ULL << 48, free_space) + : 1ULL << 48; + u64 scale = *v / 4; + + if (*v + free_space_inv >= *v) + *v += free_space_inv; + else + *v = U64_MAX; + + for (v = wp->next_alloc; + v < wp->next_alloc + ARRAY_SIZE(wp->next_alloc); v++) + *v = *v < scale ? 0 : *v - scale; +} + +static enum bucket_alloc_ret bch2_bucket_alloc_set(struct bch_fs *c, + struct write_point *wp, + unsigned nr_replicas, + enum alloc_reserve reserve, + struct bch_devs_mask *devs, + struct closure *cl) +{ + enum bucket_alloc_ret ret = NO_DEVICES; + struct dev_alloc_list devs_sorted; + struct bch_dev *ca; + unsigned i, nr_ptrs_effective = 0; + bool have_cache_dev = false; + + BUG_ON(nr_replicas > ARRAY_SIZE(wp->ptrs)); + + for (i = wp->first_ptr; i < wp->nr_ptrs; i++) { + ca = bch_dev_bkey_exists(c, wp->ptrs[i]->ptr.dev); + + nr_ptrs_effective += ca->mi.durability; + have_cache_dev |= !ca->mi.durability; + } + + if (nr_ptrs_effective >= nr_replicas) + return ALLOC_SUCCESS; + + devs_sorted = bch2_wp_alloc_list(c, wp, devs); + + for (i = 0; i < devs_sorted.nr; i++) { + int ob; + + ca = rcu_dereference(c->devs[devs_sorted.devs[i]]); + if (!ca) + continue; + + if (!ca->mi.durability && + (have_cache_dev || + wp->type != BCH_DATA_USER)) + continue; + + ob = bch2_bucket_alloc(c, ca, reserve, + wp->type == BCH_DATA_USER, cl); + if (ob < 0) { + ret = ob; + if (ret == OPEN_BUCKETS_EMPTY) + break; + continue; + } + + BUG_ON(ob <= 0 || ob > U8_MAX); + BUG_ON(wp->nr_ptrs >= ARRAY_SIZE(wp->ptrs)); + + wp->ptrs[wp->nr_ptrs++] = c->open_buckets + ob; + + bch2_wp_rescale(c, ca, wp); + + nr_ptrs_effective += ca->mi.durability; + have_cache_dev |= !ca->mi.durability; + + __clear_bit(ca->dev_idx, devs->d); + + if (nr_ptrs_effective >= nr_replicas) { + ret = ALLOC_SUCCESS; + break; + } + } + + EBUG_ON(reserve == RESERVE_MOVINGGC && + ret != ALLOC_SUCCESS && + ret != OPEN_BUCKETS_EMPTY); + + switch (ret) { + case ALLOC_SUCCESS: + return 0; + case NO_DEVICES: + return -EROFS; + case FREELIST_EMPTY: + case OPEN_BUCKETS_EMPTY: + return cl ? -EAGAIN : -ENOSPC; + default: + BUG(); + } +} + +/* Sector allocator */ + +static void bch2_writepoint_drop_ptr(struct bch_fs *c, + struct write_point *wp, + unsigned i) +{ + struct open_bucket *ob = wp->ptrs[i]; + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + BUG_ON(ca->open_buckets_partial_nr >= + ARRAY_SIZE(ca->open_buckets_partial)); + + if (wp->type == BCH_DATA_USER) { + spin_lock(&c->freelist_lock); + ob->on_partial_list = true; + ca->open_buckets_partial[ca->open_buckets_partial_nr++] = + ob - c->open_buckets; + spin_unlock(&c->freelist_lock); + + closure_wake_up(&c->open_buckets_wait); + closure_wake_up(&c->freelist_wait); + } else { + bch2_open_bucket_put(c, ob); + } + + array_remove_item(wp->ptrs, wp->nr_ptrs, i); + + if (i < wp->first_ptr) + wp->first_ptr--; +} + +void bch2_writepoint_drop_ptrs(struct bch_fs *c, + struct write_point *wp, + u16 target, bool in_target) +{ + int i; + + for (i = wp->first_ptr - 1; i >= 0; --i) + if (bch2_dev_in_target(c, wp->ptrs[i]->ptr.dev, + target) == in_target) + bch2_writepoint_drop_ptr(c, wp, i); +} + +static void verify_not_stale(struct bch_fs *c, const struct write_point *wp) +{ +#ifdef CONFIG_BCACHEFS_DEBUG + struct open_bucket *ob; + unsigned i; + + writepoint_for_each_ptr_all(wp, ob, i) { + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + BUG_ON(ptr_stale(ca, &ob->ptr)); + } +#endif +} + +static int open_bucket_add_buckets(struct bch_fs *c, + u16 target, + struct write_point *wp, + struct bch_devs_list *devs_have, + unsigned nr_replicas, + enum alloc_reserve reserve, + struct closure *cl) +{ + struct bch_devs_mask devs = c->rw_devs[wp->type]; + const struct bch_devs_mask *t; + struct open_bucket *ob; + unsigned i; + int ret; + + percpu_down_read_preempt_disable(&c->usage_lock); + rcu_read_lock(); + + /* Don't allocate from devices we already have pointers to: */ + for (i = 0; i < devs_have->nr; i++) + __clear_bit(devs_have->devs[i], devs.d); + + writepoint_for_each_ptr_all(wp, ob, i) + __clear_bit(ob->ptr.dev, devs.d); + + t = bch2_target_to_mask(c, target); + if (t) + bitmap_and(devs.d, devs.d, t->d, BCH_SB_MEMBERS_MAX); + + ret = bch2_bucket_alloc_set(c, wp, nr_replicas, reserve, &devs, cl); + + rcu_read_unlock(); + percpu_up_read_preempt_enable(&c->usage_lock); + + return ret; +} + +void bch2_writepoint_stop(struct bch_fs *c, struct bch_dev *ca, + struct write_point *wp) +{ + struct bch_devs_mask not_self; + + bitmap_complement(not_self.d, ca->self.d, BCH_SB_MEMBERS_MAX); + + mutex_lock(&wp->lock); + wp->first_ptr = wp->nr_ptrs; + bch2_writepoint_drop_ptrs(c, wp, dev_to_target(ca->dev_idx), true); + mutex_unlock(&wp->lock); +} + +static struct write_point *__writepoint_find(struct hlist_head *head, + unsigned long write_point) +{ + struct write_point *wp; + + hlist_for_each_entry_rcu(wp, head, node) + if (wp->write_point == write_point) + return wp; + + return NULL; +} + +static struct write_point *writepoint_find(struct bch_fs *c, + unsigned long write_point) +{ + struct write_point *wp, *oldest; + struct hlist_head *head; + + if (!(write_point & 1UL)) { + wp = (struct write_point *) write_point; + mutex_lock(&wp->lock); + return wp; + } + + head = writepoint_hash(c, write_point); +restart_find: + wp = __writepoint_find(head, write_point); + if (wp) { +lock_wp: + mutex_lock(&wp->lock); + if (wp->write_point == write_point) + goto out; + mutex_unlock(&wp->lock); + goto restart_find; + } + + oldest = NULL; + for (wp = c->write_points; + wp < c->write_points + ARRAY_SIZE(c->write_points); + wp++) + if (!oldest || time_before64(wp->last_used, oldest->last_used)) + oldest = wp; + + mutex_lock(&oldest->lock); + mutex_lock(&c->write_points_hash_lock); + wp = __writepoint_find(head, write_point); + if (wp && wp != oldest) { + mutex_unlock(&c->write_points_hash_lock); + mutex_unlock(&oldest->lock); + goto lock_wp; + } + + wp = oldest; + hlist_del_rcu(&wp->node); + wp->write_point = write_point; + hlist_add_head_rcu(&wp->node, head); + mutex_unlock(&c->write_points_hash_lock); +out: + wp->last_used = sched_clock(); + return wp; +} + +/* + * Get us an open_bucket we can allocate from, return with it locked: + */ +struct write_point *bch2_alloc_sectors_start(struct bch_fs *c, + unsigned target, + struct write_point_specifier write_point, + struct bch_devs_list *devs_have, + unsigned nr_replicas, + unsigned nr_replicas_required, + enum alloc_reserve reserve, + unsigned flags, + struct closure *cl) +{ + struct write_point *wp; + struct open_bucket *ob; + struct bch_dev *ca; + unsigned nr_ptrs_have, nr_ptrs_effective; + int ret, i, cache_idx = -1; + + BUG_ON(!nr_replicas || !nr_replicas_required); + + wp = writepoint_find(c, write_point.v); + + wp->first_ptr = 0; + + /* does writepoint have ptrs we can't use? */ + writepoint_for_each_ptr(wp, ob, i) + if (bch2_dev_list_has_dev(*devs_have, ob->ptr.dev)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + } + + nr_ptrs_have = wp->first_ptr; + + /* does writepoint have ptrs we don't want to use? */ + if (target) + writepoint_for_each_ptr(wp, ob, i) + if (!bch2_dev_in_target(c, ob->ptr.dev, target)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + } + + if (flags & BCH_WRITE_ONLY_SPECIFIED_DEVS) { + ret = open_bucket_add_buckets(c, target, wp, devs_have, + nr_replicas, reserve, cl); + } else { + ret = open_bucket_add_buckets(c, target, wp, devs_have, + nr_replicas, reserve, NULL); + if (!ret) + goto alloc_done; + + wp->first_ptr = nr_ptrs_have; + + ret = open_bucket_add_buckets(c, 0, wp, devs_have, + nr_replicas, reserve, cl); + } + + if (ret && ret != -EROFS) + goto err; +alloc_done: + /* check for more than one cache: */ + for (i = wp->nr_ptrs - 1; i >= wp->first_ptr; --i) { + ca = bch_dev_bkey_exists(c, wp->ptrs[i]->ptr.dev); + + if (ca->mi.durability) + continue; + + /* + * if we ended up with more than one cache device, prefer the + * one in the target we want: + */ + if (cache_idx >= 0) { + if (!bch2_dev_in_target(c, wp->ptrs[i]->ptr.dev, + target)) { + bch2_writepoint_drop_ptr(c, wp, i); + } else { + bch2_writepoint_drop_ptr(c, wp, cache_idx); + cache_idx = i; + } + } else { + cache_idx = i; + } + } + + /* we might have more effective replicas than required: */ + nr_ptrs_effective = 0; + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + nr_ptrs_effective += ca->mi.durability; + } + + if (ret == -EROFS && + nr_ptrs_effective >= nr_replicas_required) + ret = 0; + + if (ret) + goto err; + + if (nr_ptrs_effective > nr_replicas) { + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + if (ca->mi.durability && + ca->mi.durability <= nr_ptrs_effective - nr_replicas && + !bch2_dev_in_target(c, ob->ptr.dev, target)) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + nr_ptrs_effective -= ca->mi.durability; + } + } + } + + if (nr_ptrs_effective > nr_replicas) { + writepoint_for_each_ptr(wp, ob, i) { + ca = bch_dev_bkey_exists(c, ob->ptr.dev); + + if (ca->mi.durability && + ca->mi.durability <= nr_ptrs_effective - nr_replicas) { + swap(wp->ptrs[i], wp->ptrs[wp->first_ptr]); + wp->first_ptr++; + nr_ptrs_effective -= ca->mi.durability; + } + } + } + + /* Remove pointers we don't want to use: */ + if (target) + bch2_writepoint_drop_ptrs(c, wp, target, false); + + BUG_ON(wp->first_ptr >= wp->nr_ptrs); + BUG_ON(nr_ptrs_effective < nr_replicas_required); + + wp->sectors_free = UINT_MAX; + + writepoint_for_each_ptr(wp, ob, i) + wp->sectors_free = min(wp->sectors_free, ob->sectors_free); + + BUG_ON(!wp->sectors_free || wp->sectors_free == UINT_MAX); + + verify_not_stale(c, wp); + + return wp; +err: + mutex_unlock(&wp->lock); + return ERR_PTR(ret); +} + +/* + * Append pointers to the space we just allocated to @k, and mark @sectors space + * as allocated out of @ob + */ +void bch2_alloc_sectors_append_ptrs(struct bch_fs *c, struct write_point *wp, + struct bkey_i_extent *e, unsigned sectors) +{ + struct open_bucket *ob; + unsigned i; + + BUG_ON(sectors > wp->sectors_free); + wp->sectors_free -= sectors; + + writepoint_for_each_ptr(wp, ob, i) { + struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev); + struct bch_extent_ptr tmp = ob->ptr; + + EBUG_ON(bch2_extent_has_device(extent_i_to_s_c(e), ob->ptr.dev)); + + tmp.cached = bkey_extent_is_cached(&e->k) || + (!ca->mi.durability && wp->type == BCH_DATA_USER); + + tmp.offset += ca->mi.bucket_size - ob->sectors_free; + extent_ptr_append(e, tmp); + + BUG_ON(sectors > ob->sectors_free); + ob->sectors_free -= sectors; + } +} + +/* + * Append pointers to the space we just allocated to @k, and mark @sectors space + * as allocated out of @ob + */ +void bch2_alloc_sectors_done(struct bch_fs *c, struct write_point *wp) +{ + int i; + + for (i = wp->nr_ptrs - 1; i >= 0; --i) { + struct open_bucket *ob = wp->ptrs[i]; + + if (!ob->sectors_free) { + array_remove_item(wp->ptrs, wp->nr_ptrs, i); + bch2_open_bucket_put(c, ob); + } + } + + mutex_unlock(&wp->lock); +} |