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