]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/buckets.h
Disable pristine-tar option in gbp.conf, since there is no pristine-tar branch.
[bcachefs-tools-debian] / libbcachefs / buckets.h
index 5ab6f3d3413718218ddf060473f05d53ce23a3c0..6387e039f7897534e27c207dd3818dc4b6afb3b7 100644 (file)
 #define _BUCKETS_H
 
 #include "buckets_types.h"
-#include "super.h"
+#include "extents.h"
+#include "sb-members.h"
+
+static inline size_t sector_to_bucket(const struct bch_dev *ca, sector_t s)
+{
+       return div_u64(s, ca->mi.bucket_size);
+}
+
+static inline sector_t bucket_to_sector(const struct bch_dev *ca, size_t b)
+{
+       return ((sector_t) b) * ca->mi.bucket_size;
+}
+
+static inline sector_t bucket_remainder(const struct bch_dev *ca, sector_t s)
+{
+       u32 remainder;
+
+       div_u64_rem(s, ca->mi.bucket_size, &remainder);
+       return remainder;
+}
+
+static inline size_t sector_to_bucket_and_offset(const struct bch_dev *ca, sector_t s,
+                                                u32 *offset)
+{
+       return div_u64_rem(s, ca->mi.bucket_size, offset);
+}
 
 #define for_each_bucket(_b, _buckets)                          \
        for (_b = (_buckets)->b + (_buckets)->first_bucket;     \
             _b < (_buckets)->b + (_buckets)->nbuckets; _b++)
 
-#define bucket_cmpxchg(g, new, expr)                           \
-({                                                             \
-       struct bucket *_g = g;                                  \
-       u64 _v = atomic64_read(&(g)->_mark.v);                  \
-       struct bucket_mark _old;                                \
-                                                               \
-       do {                                                    \
-               (new).v.counter = _old.v.counter = _v;          \
-               expr;                                           \
-       } while ((_v = atomic64_cmpxchg(&(_g)->_mark.v,         \
-                              _old.v.counter,                  \
-                              (new).v.counter)) != _old.v.counter);\
-       _old;                                                   \
-})
+/*
+ * Ugly hack alert:
+ *
+ * We need to cram a spinlock in a single byte, because that's what we have left
+ * in struct bucket, and we care about the size of these - during fsck, we need
+ * in memory state for every single bucket on every device.
+ *
+ * We used to do
+ *   while (xchg(&b->lock, 1) cpu_relax();
+ * but, it turns out not all architectures support xchg on a single byte.
+ *
+ * So now we use bit_spin_lock(), with fun games since we can't burn a whole
+ * ulong for this - we just need to make sure the lock bit always ends up in the
+ * first byte.
+ */
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define BUCKET_LOCK_BITNR      0
+#else
+#define BUCKET_LOCK_BITNR      (BITS_PER_LONG - 1)
+#endif
 
-static inline struct bucket_array *__bucket_array(struct bch_dev *ca,
-                                                 bool gc)
+union ulong_byte_assert {
+       ulong   ulong;
+       u8      byte;
+};
+
+static inline void bucket_unlock(struct bucket *b)
 {
-       return rcu_dereference_check(ca->buckets[gc],
+       BUILD_BUG_ON(!((union ulong_byte_assert) { .ulong = 1UL << BUCKET_LOCK_BITNR }).byte);
+
+       clear_bit_unlock(BUCKET_LOCK_BITNR, (void *) &b->lock);
+       wake_up_bit((void *) &b->lock, BUCKET_LOCK_BITNR);
+}
+
+static inline void bucket_lock(struct bucket *b)
+{
+       wait_on_bit_lock((void *) &b->lock, BUCKET_LOCK_BITNR,
+                        TASK_UNINTERRUPTIBLE);
+}
+
+static inline struct bucket_array *gc_bucket_array(struct bch_dev *ca)
+{
+       return rcu_dereference_check(ca->buckets_gc,
                                     !ca->fs ||
                                     percpu_rwsem_is_held(&ca->fs->mark_lock) ||
                                     lockdep_is_held(&ca->fs->gc_lock) ||
                                     lockdep_is_held(&ca->bucket_lock));
 }
 
-static inline struct bucket_array *bucket_array(struct bch_dev *ca)
-{
-       return __bucket_array(ca, false);
-}
-
-static inline struct bucket *__bucket(struct bch_dev *ca, size_t b, bool gc)
+static inline struct bucket *gc_bucket(struct bch_dev *ca, size_t b)
 {
-       struct bucket_array *buckets = __bucket_array(ca, gc);
+       struct bucket_array *buckets = gc_bucket_array(ca);
 
        BUG_ON(b < buckets->first_bucket || b >= buckets->nbuckets);
        return buckets->b + b;
 }
 
-static inline struct bucket *bucket(struct bch_dev *ca, size_t b)
+static inline struct bucket_gens *bucket_gens(struct bch_dev *ca)
 {
-       return __bucket(ca, b, false);
+       return rcu_dereference_check(ca->bucket_gens,
+                                    !ca->fs ||
+                                    percpu_rwsem_is_held(&ca->fs->mark_lock) ||
+                                    lockdep_is_held(&ca->fs->gc_lock) ||
+                                    lockdep_is_held(&ca->bucket_lock));
 }
 
-static inline void bucket_io_clock_reset(struct bch_fs *c, struct bch_dev *ca,
-                                        size_t b, int rw)
+static inline u8 *bucket_gen(struct bch_dev *ca, size_t b)
 {
-       bucket(ca, b)->io_time[rw] = c->bucket_clock[rw].hand;
+       struct bucket_gens *gens = bucket_gens(ca);
+
+       BUG_ON(b < gens->first_bucket || b >= gens->nbuckets);
+       return gens->b + b;
 }
 
-static inline u16 bucket_last_io(struct bch_fs *c, struct bucket *g, int rw)
+static inline size_t PTR_BUCKET_NR(const struct bch_dev *ca,
+                                  const struct bch_extent_ptr *ptr)
 {
-       return c->bucket_clock[rw].hand - g->io_time[rw];
+       return sector_to_bucket(ca, ptr->offset);
 }
 
-/*
- * bucket_gc_gen() returns the difference between the bucket's current gen and
- * the oldest gen of any pointer into that bucket in the btree.
- */
-
-static inline u8 bucket_gc_gen(struct bch_dev *ca, size_t b)
+static inline struct bpos PTR_BUCKET_POS(const struct bch_fs *c,
+                                  const struct bch_extent_ptr *ptr)
 {
-       struct bucket *g = bucket(ca, b);
+       struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 
-       return g->mark.gen - g->oldest_gen;
+       return POS(ptr->dev, PTR_BUCKET_NR(ca, ptr));
 }
 
-static inline size_t PTR_BUCKET_NR(const struct bch_dev *ca,
-                                  const struct bch_extent_ptr *ptr)
+static inline struct bpos PTR_BUCKET_POS_OFFSET(const struct bch_fs *c,
+                                               const struct bch_extent_ptr *ptr,
+                                               u32 *bucket_offset)
 {
-       return sector_to_bucket(ca, ptr->offset);
+       struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
+
+       return POS(ptr->dev, sector_to_bucket_and_offset(ca, ptr->offset, bucket_offset));
 }
 
-static inline struct bucket *PTR_BUCKET(struct bch_dev *ca,
-                                       const struct bch_extent_ptr *ptr,
-                                       bool gc)
+static inline struct bucket *PTR_GC_BUCKET(struct bch_dev *ca,
+                                          const struct bch_extent_ptr *ptr)
 {
-       return __bucket(ca, PTR_BUCKET_NR(ca, ptr), gc);
+       return gc_bucket(ca, PTR_BUCKET_NR(ca, ptr));
 }
 
-static inline struct bucket_mark ptr_bucket_mark(struct bch_dev *ca,
-                                                const struct bch_extent_ptr *ptr)
+static inline enum bch_data_type ptr_data_type(const struct bkey *k,
+                                              const struct bch_extent_ptr *ptr)
 {
-       struct bucket_mark m;
+       if (bkey_is_btree_ptr(k))
+               return BCH_DATA_btree;
 
-       rcu_read_lock();
-       m = READ_ONCE(PTR_BUCKET(ca, ptr, 0)->mark);
-       rcu_read_unlock();
+       return ptr->cached ? BCH_DATA_cached : BCH_DATA_user;
+}
+
+static inline s64 ptr_disk_sectors(s64 sectors, struct extent_ptr_decoded p)
+{
+       EBUG_ON(sectors < 0);
 
-       return m;
+       return crc_is_compressed(p.crc)
+               ? DIV_ROUND_UP_ULL(sectors * p.crc.compressed_size,
+                                  p.crc.uncompressed_size)
+               : sectors;
 }
 
 static inline int gen_cmp(u8 a, u8 b)
@@ -125,175 +182,264 @@ static inline int gen_after(u8 a, u8 b)
 static inline u8 ptr_stale(struct bch_dev *ca,
                           const struct bch_extent_ptr *ptr)
 {
-       return gen_after(ptr_bucket_mark(ca, ptr).gen, ptr->gen);
-}
+       u8 ret;
 
-static inline unsigned __ptr_disk_sectors(struct extent_ptr_decoded p,
-                                         unsigned live_size)
-{
-       return live_size && p.crc.compression_type
-               ? max(1U, DIV_ROUND_UP(live_size * p.crc.compressed_size,
-                                      p.crc.uncompressed_size))
-               : live_size;
+       rcu_read_lock();
+       ret = gen_after(*bucket_gen(ca, PTR_BUCKET_NR(ca, ptr)), ptr->gen);
+       rcu_read_unlock();
+
+       return ret;
 }
 
-static inline unsigned ptr_disk_sectors(struct extent_ptr_decoded p)
+/* Device usage: */
+
+void bch2_dev_usage_read_fast(struct bch_dev *, struct bch_dev_usage *);
+static inline struct bch_dev_usage bch2_dev_usage_read(struct bch_dev *ca)
 {
-       return __ptr_disk_sectors(p, p.crc.live_size);
+       struct bch_dev_usage ret;
+
+       bch2_dev_usage_read_fast(ca, &ret);
+       return ret;
 }
 
-/* bucket gc marks */
+void bch2_dev_usage_init(struct bch_dev *);
+void bch2_dev_usage_to_text(struct printbuf *, struct bch_dev_usage *);
 
-static inline unsigned bucket_sectors_used(struct bucket_mark mark)
+static inline u64 bch2_dev_buckets_reserved(struct bch_dev *ca, enum bch_watermark watermark)
 {
-       return mark.dirty_sectors + mark.cached_sectors;
+       s64 reserved = 0;
+
+       switch (watermark) {
+       case BCH_WATERMARK_NR:
+               BUG();
+       case BCH_WATERMARK_stripe:
+               reserved += ca->mi.nbuckets >> 6;
+               fallthrough;
+       case BCH_WATERMARK_normal:
+               reserved += ca->mi.nbuckets >> 6;
+               fallthrough;
+       case BCH_WATERMARK_copygc:
+               reserved += ca->nr_btree_reserve;
+               fallthrough;
+       case BCH_WATERMARK_btree:
+               reserved += ca->nr_btree_reserve;
+               fallthrough;
+       case BCH_WATERMARK_btree_copygc:
+       case BCH_WATERMARK_reclaim:
+               break;
+       }
+
+       return reserved;
 }
 
-static inline bool bucket_unused(struct bucket_mark mark)
+static inline u64 dev_buckets_free(struct bch_dev *ca,
+                                  struct bch_dev_usage usage,
+                                  enum bch_watermark watermark)
 {
-       return !mark.owned_by_allocator &&
-               !mark.data_type &&
-               !bucket_sectors_used(mark);
+       return max_t(s64, 0,
+                    usage.d[BCH_DATA_free].buckets -
+                    ca->nr_open_buckets -
+                    bch2_dev_buckets_reserved(ca, watermark));
 }
 
-static inline bool is_available_bucket(struct bucket_mark mark)
+static inline u64 __dev_buckets_available(struct bch_dev *ca,
+                                         struct bch_dev_usage usage,
+                                         enum bch_watermark watermark)
 {
-       return (!mark.owned_by_allocator &&
-               !mark.dirty_sectors &&
-               !mark.stripe);
+       return max_t(s64, 0,
+                      usage.d[BCH_DATA_free].buckets
+                    + usage.d[BCH_DATA_cached].buckets
+                    + usage.d[BCH_DATA_need_gc_gens].buckets
+                    + usage.d[BCH_DATA_need_discard].buckets
+                    - ca->nr_open_buckets
+                    - bch2_dev_buckets_reserved(ca, watermark));
 }
 
-static inline bool bucket_needs_journal_commit(struct bucket_mark m,
-                                              u16 last_seq_ondisk)
+static inline u64 dev_buckets_available(struct bch_dev *ca,
+                                       enum bch_watermark watermark)
 {
-       return m.journal_seq_valid &&
-               ((s16) m.journal_seq - (s16) last_seq_ondisk > 0);
+       return __dev_buckets_available(ca, bch2_dev_usage_read(ca), watermark);
 }
 
-/* Device usage: */
-
-struct bch_dev_usage bch2_dev_usage_read(struct bch_fs *, struct bch_dev *);
-
-void bch2_dev_usage_from_buckets(struct bch_fs *);
+/* Filesystem usage: */
 
-static inline u64 __dev_buckets_available(struct bch_dev *ca,
-                                         struct bch_dev_usage stats)
+static inline unsigned __fs_usage_u64s(unsigned nr_replicas)
 {
-       u64 total = ca->mi.nbuckets - ca->mi.first_bucket;
-
-       if (WARN_ONCE(stats.buckets_unavailable > total,
-                     "buckets_unavailable overflow (%llu > %llu)\n",
-                     stats.buckets_unavailable, total))
-               return 0;
-
-       return total - stats.buckets_unavailable;
+       return sizeof(struct bch_fs_usage) / sizeof(u64) + nr_replicas;
 }
 
-/*
- * Number of reclaimable buckets - only for use by the allocator thread:
- */
-static inline u64 dev_buckets_available(struct bch_fs *c, struct bch_dev *ca)
+static inline unsigned fs_usage_u64s(struct bch_fs *c)
 {
-       return __dev_buckets_available(ca, bch2_dev_usage_read(c, ca));
+       return __fs_usage_u64s(READ_ONCE(c->replicas.nr));
 }
 
-static inline u64 __dev_buckets_free(struct bch_dev *ca,
-                                    struct bch_dev_usage stats)
+static inline unsigned __fs_usage_online_u64s(unsigned nr_replicas)
 {
-       return __dev_buckets_available(ca, stats) +
-               fifo_used(&ca->free[RESERVE_NONE]) +
-               fifo_used(&ca->free_inc);
+       return sizeof(struct bch_fs_usage_online) / sizeof(u64) + nr_replicas;
 }
 
-static inline u64 dev_buckets_free(struct bch_fs *c, struct bch_dev *ca)
+static inline unsigned fs_usage_online_u64s(struct bch_fs *c)
 {
-       return __dev_buckets_free(ca, bch2_dev_usage_read(c, ca));
+       return __fs_usage_online_u64s(READ_ONCE(c->replicas.nr));
 }
 
-/* Filesystem usage: */
-
-static inline unsigned fs_usage_u64s(struct bch_fs *c)
+static inline unsigned dev_usage_u64s(void)
 {
-
-       return sizeof(struct bch_fs_usage) / sizeof(u64) +
-               READ_ONCE(c->replicas.nr);
+       return sizeof(struct bch_dev_usage) / sizeof(u64);
 }
 
-void bch2_fs_usage_scratch_put(struct bch_fs *, struct bch_fs_usage *);
-struct bch_fs_usage *bch2_fs_usage_scratch_get(struct bch_fs *);
-
 u64 bch2_fs_usage_read_one(struct bch_fs *, u64 *);
 
-struct bch_fs_usage *bch2_fs_usage_read(struct bch_fs *);
+struct bch_fs_usage_online *bch2_fs_usage_read(struct bch_fs *);
 
 void bch2_fs_usage_acc_to_base(struct bch_fs *, unsigned);
 
 void bch2_fs_usage_to_text(struct printbuf *,
-                          struct bch_fs *, struct bch_fs_usage *);
+                          struct bch_fs *, struct bch_fs_usage_online *);
 
-u64 bch2_fs_sectors_used(struct bch_fs *, struct bch_fs_usage *);
+u64 bch2_fs_sectors_used(struct bch_fs *, struct bch_fs_usage_online *);
 
 struct bch_fs_usage_short
 bch2_fs_usage_read_short(struct bch_fs *);
 
+void bch2_dev_usage_update(struct bch_fs *, struct bch_dev *,
+                          const struct bch_alloc_v4 *,
+                          const struct bch_alloc_v4 *, u64, bool);
+void bch2_dev_usage_update_m(struct bch_fs *, struct bch_dev *,
+                            struct bucket *, struct bucket *);
+
 /* key/bucket marking: */
 
-void bch2_bucket_seq_cleanup(struct bch_fs *);
+static inline struct bch_fs_usage *fs_usage_ptr(struct bch_fs *c,
+                                               unsigned journal_seq,
+                                               bool gc)
+{
+       percpu_rwsem_assert_held(&c->mark_lock);
+       BUG_ON(!gc && !journal_seq);
+
+       return this_cpu_ptr(gc
+                           ? c->usage_gc
+                           : c->usage[journal_seq & JOURNAL_BUF_MASK]);
+}
+
+int bch2_update_replicas(struct bch_fs *, struct bkey_s_c,
+                        struct bch_replicas_entry_v1 *, s64,
+                        unsigned, bool);
+int bch2_update_replicas_list(struct btree_trans *,
+                        struct bch_replicas_entry_v1 *, s64);
+int bch2_update_cached_sectors_list(struct btree_trans *, unsigned, s64);
+int bch2_replicas_deltas_realloc(struct btree_trans *, unsigned);
+
 void bch2_fs_usage_initialize(struct bch_fs *);
 
-void bch2_invalidate_bucket(struct bch_fs *, struct bch_dev *,
-                           size_t, struct bucket_mark *);
-void bch2_mark_alloc_bucket(struct bch_fs *, struct bch_dev *,
-                           size_t, bool, struct gc_pos, unsigned);
-void bch2_mark_metadata_bucket(struct bch_fs *, struct bch_dev *,
-                              size_t, enum bch_data_type, unsigned,
-                              struct gc_pos, unsigned);
-
-#define BCH_BUCKET_MARK_INSERT                 (1 << 0)
-#define BCH_BUCKET_MARK_OVERWRITE              (1 << 1)
-#define BCH_BUCKET_MARK_BUCKET_INVALIDATE      (1 << 2)
-#define BCH_BUCKET_MARK_GC                     (1 << 3)
-#define BCH_BUCKET_MARK_ALLOC_READ             (1 << 4)
-#define BCH_BUCKET_MARK_NOATOMIC               (1 << 5)
-
-int bch2_mark_key_locked(struct bch_fs *, struct bkey_s_c, s64,
-                        struct bch_fs_usage *, u64, unsigned);
-int bch2_mark_key(struct bch_fs *, struct bkey_s_c, s64,
-                 struct bch_fs_usage *, u64, unsigned);
-int bch2_fs_usage_apply(struct bch_fs *, struct bch_fs_usage *,
-                       struct disk_reservation *, unsigned);
-
-int bch2_mark_overwrite(struct btree_trans *, struct btree_iter *,
-                       struct bkey_s_c, struct bkey_i *,
-                       struct bch_fs_usage *, unsigned);
-int bch2_mark_update(struct btree_trans *, struct btree_insert_entry *,
-                    struct bch_fs_usage *, unsigned);
-
-void bch2_replicas_delta_list_apply(struct bch_fs *,
-                                   struct bch_fs_usage *,
-                                   struct replicas_delta_list *);
-int bch2_trans_mark_key(struct btree_trans *, struct bkey_s_c, s64, unsigned);
-int bch2_trans_mark_update(struct btree_trans *,
-                          struct btree_iter *iter,
-                          struct bkey_i *insert);
-void bch2_trans_fs_usage_apply(struct btree_trans *, struct bch_fs_usage *);
+int bch2_check_bucket_ref(struct btree_trans *, struct bkey_s_c,
+                         const struct bch_extent_ptr *,
+                         s64, enum bch_data_type, u8, u8, u32);
+
+int bch2_mark_metadata_bucket(struct bch_fs *, struct bch_dev *,
+                             size_t, enum bch_data_type, unsigned,
+                             struct gc_pos, unsigned);
+
+int bch2_trigger_extent(struct btree_trans *, enum btree_id, unsigned,
+                       struct bkey_s_c, struct bkey_s, unsigned);
+int bch2_trigger_reservation(struct btree_trans *, enum btree_id, unsigned,
+                         struct bkey_s_c, struct bkey_s, unsigned);
+
+#define trigger_run_overwrite_then_insert(_fn, _trans, _btree_id, _level, _old, _new, _flags)\
+({                                                                                             \
+       int ret = 0;                                                                            \
+                                                                                               \
+       if (_old.k->type)                                                                       \
+               ret = _fn(_trans, _btree_id, _level, _old, _flags & ~BTREE_TRIGGER_INSERT);     \
+       if (!ret && _new.k->type)                                                               \
+               ret = _fn(_trans, _btree_id, _level, _new.s_c, _flags & ~BTREE_TRIGGER_OVERWRITE);\
+       ret;                                                                                    \
+})
+
+void bch2_trans_account_disk_usage_change(struct btree_trans *);
 
-/* disk reservations: */
+void bch2_trans_fs_usage_revert(struct btree_trans *, struct replicas_delta_list *);
+int bch2_trans_fs_usage_apply(struct btree_trans *, struct replicas_delta_list *);
+
+int bch2_trans_mark_metadata_bucket(struct btree_trans *, struct bch_dev *,
+                                   size_t, enum bch_data_type, unsigned);
+int bch2_trans_mark_dev_sb(struct bch_fs *, struct bch_dev *);
+int bch2_trans_mark_dev_sbs(struct bch_fs *);
+
+static inline bool is_superblock_bucket(struct bch_dev *ca, u64 b)
+{
+       struct bch_sb_layout *layout = &ca->disk_sb.sb->layout;
+       u64 b_offset    = bucket_to_sector(ca, b);
+       u64 b_end       = bucket_to_sector(ca, b + 1);
+       unsigned i;
 
-void __bch2_disk_reservation_put(struct bch_fs *, struct disk_reservation *);
+       if (!b)
+               return true;
+
+       for (i = 0; i < layout->nr_superblocks; i++) {
+               u64 offset = le64_to_cpu(layout->sb_offset[i]);
+               u64 end = offset + (1 << layout->sb_max_size_bits);
+
+               if (!(offset >= b_end || end <= b_offset))
+                       return true;
+       }
+
+       return false;
+}
+
+static inline const char *bch2_data_type_str(enum bch_data_type type)
+{
+       return type < BCH_DATA_NR
+               ? __bch2_data_types[type]
+               : "(invalid data type)";
+}
+
+static inline void bch2_prt_data_type(struct printbuf *out, enum bch_data_type type)
+{
+       if (type < BCH_DATA_NR)
+               prt_str(out, __bch2_data_types[type]);
+       else
+               prt_printf(out, "(invalid data type %u)", type);
+}
+
+/* disk reservations: */
 
 static inline void bch2_disk_reservation_put(struct bch_fs *c,
                                             struct disk_reservation *res)
 {
-       if (res->sectors)
-               __bch2_disk_reservation_put(c, res);
+       if (res->sectors) {
+               this_cpu_sub(*c->online_reserved, res->sectors);
+               res->sectors = 0;
+       }
 }
 
 #define BCH_DISK_RESERVATION_NOFAIL            (1 << 0)
 
-int bch2_disk_reservation_add(struct bch_fs *,
-                            struct disk_reservation *,
-                            unsigned, int);
+int __bch2_disk_reservation_add(struct bch_fs *,
+                               struct disk_reservation *,
+                               u64, int);
+
+static inline int bch2_disk_reservation_add(struct bch_fs *c, struct disk_reservation *res,
+                                           u64 sectors, int flags)
+{
+#ifdef __KERNEL__
+       u64 old, new;
+
+       do {
+               old = this_cpu_read(c->pcpu->sectors_available);
+               if (sectors > old)
+                       return __bch2_disk_reservation_add(c, res, sectors, flags);
+
+               new = old - sectors;
+       } while (this_cpu_cmpxchg(c->pcpu->sectors_available, old, new) != old);
+
+       this_cpu_add(*c->online_reserved, sectors);
+       res->sectors                    += sectors;
+       return 0;
+#else
+       return __bch2_disk_reservation_add(c, res, sectors, flags);
+#endif
+}
 
 static inline struct disk_reservation
 bch2_disk_reservation_init(struct bch_fs *c, unsigned nr_replicas)
@@ -310,8 +456,7 @@ bch2_disk_reservation_init(struct bch_fs *c, unsigned nr_replicas)
 
 static inline int bch2_disk_reservation_get(struct bch_fs *c,
                                            struct disk_reservation *res,
-                                           unsigned sectors,
-                                           unsigned nr_replicas,
+                                           u64 sectors, unsigned nr_replicas,
                                            int flags)
 {
        *res = bch2_disk_reservation_init(c, nr_replicas);
@@ -319,6 +464,13 @@ static inline int bch2_disk_reservation_get(struct bch_fs *c,
        return bch2_disk_reservation_add(c, res, sectors * nr_replicas, flags);
 }
 
+#define RESERVE_FACTOR 6
+
+static inline u64 avail_factor(u64 r)
+{
+       return div_u64(r << RESERVE_FACTOR, (1 << RESERVE_FACTOR) + 1);
+}
+
 int bch2_dev_buckets_resize(struct bch_fs *, struct bch_dev *, u64);
 void bch2_dev_buckets_free(struct bch_dev *);
 int bch2_dev_buckets_alloc(struct bch_fs *, struct bch_dev *);