fs/bcachefs/btree_update_interior.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_BTREE_UPDATE_INTERIOR_H
   3 #define _BCACHEFS_BTREE_UPDATE_INTERIOR_H
   4
   5 #include "btree_cache.h"
   6 #include "btree_locking.h"
   7 #include "btree_update.h"
   8
   9 #define BTREE_UPDATE_NODES_MAX          ((BTREE_MAX_DEPTH - 2) * 2 + GC_MERGE_NODES)
  10
  11 #define BTREE_UPDATE_JOURNAL_RES        (BTREE_UPDATE_NODES_MAX * (BKEY_BTREE_PTR_U64s_MAX + 1))
  12
  13 /*
  14  * Tracks an in progress split/rewrite of a btree node and the update to the
  15  * parent node:
  16  *
  17  * When we split/rewrite a node, we do all the updates in memory without
  18  * waiting for any writes to complete - we allocate the new node(s) and update
  19  * the parent node, possibly recursively up to the root.
  20  *
  21  * The end result is that we have one or more new nodes being written -
  22  * possibly several, if there were multiple splits - and then a write (updating
  23  * an interior node) which will make all these new nodes visible.
  24  *
  25  * Additionally, as we split/rewrite nodes we free the old nodes - but the old
  26  * nodes can't be freed (their space on disk can't be reclaimed) until the
  27  * update to the interior node that makes the new node visible completes -
  28  * until then, the old nodes are still reachable on disk.
  29  *
  30  */
  31 struct btree_update {
  32         struct closure                  cl;
  33         struct bch_fs                   *c;
  34         u64                             start_time;
  35
  36         struct list_head                list;
  37         struct list_head                unwritten_list;
  38
  39         /* What kind of update are we doing? */
  40         enum {
  41                 BTREE_INTERIOR_NO_UPDATE,
  42                 BTREE_INTERIOR_UPDATING_NODE,
  43                 BTREE_INTERIOR_UPDATING_ROOT,
  44                 BTREE_INTERIOR_UPDATING_AS,
  45         } mode;
  46
  47         unsigned                        nodes_written:1;
  48         unsigned                        took_gc_lock:1;
  49
  50         enum btree_id                   btree_id;
  51         unsigned                        update_level;
  52
  53         struct disk_reservation         disk_res;
  54
  55         /*
  56          * BTREE_INTERIOR_UPDATING_NODE:
  57          * The update that made the new nodes visible was a regular update to an
  58          * existing interior node - @b. We can't write out the update to @b
  59          * until the new nodes we created are finished writing, so we block @b
  60          * from writing by putting this btree_interior update on the
  61          * @b->write_blocked list with @write_blocked_list:
  62          */
  63         struct btree                    *b;
  64         struct list_head                write_blocked_list;
  65
  66         /*
  67          * We may be freeing nodes that were dirty, and thus had journal entries
  68          * pinned: we need to transfer the oldest of those pins to the
  69          * btree_update operation, and release it when the new node(s)
  70          * are all persistent and reachable:
  71          */
  72         struct journal_entry_pin        journal;
  73
  74         /* Preallocated nodes we reserve when we start the update: */
  75         struct prealloc_nodes {
  76                 struct btree            *b[BTREE_UPDATE_NODES_MAX];
  77                 unsigned                nr;
  78         }                               prealloc_nodes[2];
  79
  80         /* Nodes being freed: */
  81         struct keylist                  old_keys;
  82         u64                             _old_keys[BTREE_UPDATE_NODES_MAX *
  83                                                   BKEY_BTREE_PTR_U64s_MAX];
  84
  85         /* Nodes being added: */
  86         struct keylist                  new_keys;
  87         u64                             _new_keys[BTREE_UPDATE_NODES_MAX *
  88                                                   BKEY_BTREE_PTR_U64s_MAX];
  89
  90         /* New nodes, that will be made reachable by this update: */
  91         struct btree                    *new_nodes[BTREE_UPDATE_NODES_MAX];
  92         unsigned                        nr_new_nodes;
  93
  94         struct btree                    *old_nodes[BTREE_UPDATE_NODES_MAX];
  95         __le64                          old_nodes_seq[BTREE_UPDATE_NODES_MAX];
  96         unsigned                        nr_old_nodes;
  97
  98         open_bucket_idx_t               open_buckets[BTREE_UPDATE_NODES_MAX *
  99                                                      BCH_REPLICAS_MAX];
 100         open_bucket_idx_t               nr_open_buckets;
 101
 102         unsigned                        journal_u64s;
 103         u64                             journal_entries[BTREE_UPDATE_JOURNAL_RES];
 104
 105         /* Only here to reduce stack usage on recursive splits: */
 106         struct keylist                  parent_keys;
 107         /*
 108          * Enough room for btree_split's keys without realloc - btree node
 109          * pointers never have crc/compression info, so we only need to acount
 110          * for the pointers for three keys
 111          */
 112         u64                             inline_keys[BKEY_BTREE_PTR_U64s_MAX * 3];
 113 };
 114
 115 struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *,
 116                                                   struct btree_trans *,
 117                                                   struct btree *,
 118                                                   struct bkey_format);
 119
 120 int bch2_btree_split_leaf(struct btree_trans *, btree_path_idx_t, unsigned);
 121
 122 int bch2_btree_increase_depth(struct btree_trans *, btree_path_idx_t, unsigned);
 123
 124 int __bch2_foreground_maybe_merge(struct btree_trans *, btree_path_idx_t,
 125                                   unsigned, unsigned, enum btree_node_sibling);
 126
 127 static inline int bch2_foreground_maybe_merge_sibling(struct btree_trans *trans,
 128                                         btree_path_idx_t path_idx,
 129                                         unsigned level, unsigned flags,
 130                                         enum btree_node_sibling sib)
 131 {
 132         struct btree_path *path = trans->paths + path_idx;
 133         struct btree *b;
 134
 135         EBUG_ON(!btree_node_locked(path, level));
 136
 137         b = path->l[level].b;
 138         if (b->sib_u64s[sib] > trans->c->btree_foreground_merge_threshold)
 139                 return 0;
 140
 141         return __bch2_foreground_maybe_merge(trans, path_idx, level, flags, sib);
 142 }
 143
 144 static inline int bch2_foreground_maybe_merge(struct btree_trans *trans,
 145                                               btree_path_idx_t path,
 146                                               unsigned level,
 147                                               unsigned flags)
 148 {
 149         return  bch2_foreground_maybe_merge_sibling(trans, path, level, flags,
 150                                                     btree_prev_sib) ?:
 151                 bch2_foreground_maybe_merge_sibling(trans, path, level, flags,
 152                                                     btree_next_sib);
 153 }
 154
 155 int bch2_btree_node_rewrite(struct btree_trans *, struct btree_iter *,
 156                             struct btree *, unsigned);
 157 void bch2_btree_node_rewrite_async(struct bch_fs *, struct btree *);
 158 int bch2_btree_node_update_key(struct btree_trans *, struct btree_iter *,
 159                                struct btree *, struct bkey_i *,
 160                                unsigned, bool);
 161 int bch2_btree_node_update_key_get_iter(struct btree_trans *, struct btree *,
 162                                         struct bkey_i *, unsigned, bool);
 163
 164 void bch2_btree_set_root_for_read(struct bch_fs *, struct btree *);
 165 void bch2_btree_root_alloc(struct bch_fs *, enum btree_id);
 166
 167 static inline unsigned btree_update_reserve_required(struct bch_fs *c,
 168                                                      struct btree *b)
 169 {
 170         unsigned depth = btree_node_root(c, b)->c.level + 1;
 171
 172         /*
 173          * Number of nodes we might have to allocate in a worst case btree
 174          * split operation - we split all the way up to the root, then allocate
 175          * a new root, unless we're already at max depth:
 176          */
 177         if (depth < BTREE_MAX_DEPTH)
 178                 return (depth - b->c.level) * 2 + 1;
 179         else
 180                 return (depth - b->c.level) * 2 - 1;
 181 }
 182
 183 static inline void btree_node_reset_sib_u64s(struct btree *b)
 184 {
 185         b->sib_u64s[0] = b->nr.live_u64s;
 186         b->sib_u64s[1] = b->nr.live_u64s;
 187 }
 188
 189 static inline void *btree_data_end(struct btree *b)
 190 {
 191         return (void *) b->data + btree_buf_bytes(b);
 192 }
 193
 194 static inline struct bkey_packed *unwritten_whiteouts_start(struct btree *b)
 195 {
 196         return (void *) ((u64 *) btree_data_end(b) - b->whiteout_u64s);
 197 }
 198
 199 static inline struct bkey_packed *unwritten_whiteouts_end(struct btree *b)
 200 {
 201         return btree_data_end(b);
 202 }
 203
 204 static inline void *write_block(struct btree *b)
 205 {
 206         return (void *) b->data + (b->written << 9);
 207 }
 208
 209 static inline bool __btree_addr_written(struct btree *b, void *p)
 210 {
 211         return p < write_block(b);
 212 }
 213
 214 static inline bool bset_written(struct btree *b, struct bset *i)
 215 {
 216         return __btree_addr_written(b, i);
 217 }
 218
 219 static inline bool bkey_written(struct btree *b, struct bkey_packed *k)
 220 {
 221         return __btree_addr_written(b, k);
 222 }
 223
 224 static inline ssize_t __bch2_btree_u64s_remaining(struct btree *b, void *end)
 225 {
 226         ssize_t used = bset_byte_offset(b, end) / sizeof(u64) +
 227                 b->whiteout_u64s;
 228         ssize_t total = btree_buf_bytes(b) >> 3;
 229
 230         /* Always leave one extra u64 for bch2_varint_decode: */
 231         used++;
 232
 233         return total - used;
 234 }
 235
 236 static inline size_t bch2_btree_keys_u64s_remaining(struct btree *b)
 237 {
 238         ssize_t remaining = __bch2_btree_u64s_remaining(b,
 239                                 btree_bkey_last(b, bset_tree_last(b)));
 240
 241         BUG_ON(remaining < 0);
 242
 243         if (bset_written(b, btree_bset_last(b)))
 244                 return 0;
 245
 246         return remaining;
 247 }
 248
 249 #define BTREE_WRITE_SET_U64s_BITS       9
 250
 251 static inline unsigned btree_write_set_buffer(struct btree *b)
 252 {
 253         /*
 254          * Could buffer up larger amounts of keys for btrees with larger keys,
 255          * pending benchmarking:
 256          */
 257         return 8 << BTREE_WRITE_SET_U64s_BITS;
 258 }
 259
 260 static inline struct btree_node_entry *want_new_bset(struct bch_fs *c, struct btree *b)
 261 {
 262         struct bset_tree *t = bset_tree_last(b);
 263         struct btree_node_entry *bne = max(write_block(b),
 264                         (void *) btree_bkey_last(b, bset_tree_last(b)));
 265         ssize_t remaining_space =
 266                 __bch2_btree_u64s_remaining(b, bne->keys.start);
 267
 268         if (unlikely(bset_written(b, bset(b, t)))) {
 269                 if (remaining_space > (ssize_t) (block_bytes(c) >> 3))
 270                         return bne;
 271         } else {
 272                 if (unlikely(bset_u64s(t) * sizeof(u64) > btree_write_set_buffer(b)) &&
 273                     remaining_space > (ssize_t) (btree_write_set_buffer(b) >> 3))
 274                         return bne;
 275         }
 276
 277         return NULL;
 278 }
 279
 280 static inline void push_whiteout(struct btree *b, struct bpos pos)
 281 {
 282         struct bkey_packed k;
 283
 284         BUG_ON(bch2_btree_keys_u64s_remaining(b) < BKEY_U64s);
 285         EBUG_ON(btree_node_just_written(b));
 286
 287         if (!bkey_pack_pos(&k, pos, b)) {
 288                 struct bkey *u = (void *) &k;
 289
 290                 bkey_init(u);
 291                 u->p = pos;
 292         }
 293
 294         k.needs_whiteout = true;
 295
 296         b->whiteout_u64s += k.u64s;
 297         bkey_p_copy(unwritten_whiteouts_start(b), &k);
 298 }
 299
 300 /*
 301  * write lock must be held on @b (else the dirty bset that we were going to
 302  * insert into could be written out from under us)
 303  */
 304 static inline bool bch2_btree_node_insert_fits(struct btree *b, unsigned u64s)
 305 {
 306         if (unlikely(btree_node_need_rewrite(b)))
 307                 return false;
 308
 309         return u64s <= bch2_btree_keys_u64s_remaining(b);
 310 }
 311
 312 void bch2_btree_updates_to_text(struct printbuf *, struct bch_fs *);
 313
 314 bool bch2_btree_interior_updates_flush(struct bch_fs *);
 315
 316 void bch2_journal_entry_to_btree_root(struct bch_fs *, struct jset_entry *);
 317 struct jset_entry *bch2_btree_roots_to_journal_entries(struct bch_fs *,
 318                                         struct jset_entry *, unsigned long);
 319
 320 void bch2_do_pending_node_rewrites(struct bch_fs *);
 321 void bch2_free_pending_node_rewrites(struct bch_fs *);
 322
 323 void bch2_fs_btree_interior_update_exit(struct bch_fs *);
 324 void bch2_fs_btree_interior_update_init_early(struct bch_fs *);
 325 int bch2_fs_btree_interior_update_init(struct bch_fs *);
 326
 327 #endif /* _BCACHEFS_BTREE_UPDATE_INTERIOR_H */