fs/bcachefs/extent_update.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "btree_update.h"
   4 #include "btree_update_interior.h"
   5 #include "buckets.h"
   6 #include "debug.h"
   7 #include "extents.h"
   8 #include "extent_update.h"
   9
  10 /*
  11  * This counts the number of iterators to the alloc & ec btrees we'll need
  12  * inserting/removing this extent:
  13  */
  14 static unsigned bch2_bkey_nr_alloc_ptrs(struct bkey_s_c k)
  15 {
  16         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
  17         const union bch_extent_entry *entry;
  18         unsigned ret = 0, lru = 0;
  19
  20         bkey_extent_entry_for_each(ptrs, entry) {
  21                 switch (__extent_entry_type(entry)) {
  22                 case BCH_EXTENT_ENTRY_ptr:
  23                         /* Might also be updating LRU btree */
  24                         if (entry->ptr.cached)
  25                                 lru++;
  26
  27                         fallthrough;
  28                 case BCH_EXTENT_ENTRY_stripe_ptr:
  29                         ret++;
  30                 }
  31         }
  32
  33         /*
  34          * Updating keys in the alloc btree may also update keys in the
  35          * freespace or discard btrees:
  36          */
  37         return lru + ret * 2;
  38 }
  39
  40 static int count_iters_for_insert(struct btree_trans *trans,
  41                                   struct bkey_s_c k,
  42                                   unsigned offset,
  43                                   struct bpos *end,
  44                                   unsigned *nr_iters,
  45                                   unsigned max_iters)
  46 {
  47         int ret = 0, ret2 = 0;
  48
  49         if (*nr_iters >= max_iters) {
  50                 *end = bpos_min(*end, k.k->p);
  51                 ret = 1;
  52         }
  53
  54         switch (k.k->type) {
  55         case KEY_TYPE_extent:
  56         case KEY_TYPE_reflink_v:
  57                 *nr_iters += bch2_bkey_nr_alloc_ptrs(k);
  58
  59                 if (*nr_iters >= max_iters) {
  60                         *end = bpos_min(*end, k.k->p);
  61                         ret = 1;
  62                 }
  63
  64                 break;
  65         case KEY_TYPE_reflink_p: {
  66                 struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
  67                 u64 idx = le64_to_cpu(p.v->idx);
  68                 unsigned sectors = bpos_min(*end, p.k->p).offset -
  69                         bkey_start_offset(p.k);
  70                 struct btree_iter iter;
  71                 struct bkey_s_c r_k;
  72
  73                 for_each_btree_key_norestart(trans, iter,
  74                                    BTREE_ID_reflink, POS(0, idx + offset),
  75                                    BTREE_ITER_slots, r_k, ret2) {
  76                         if (bkey_ge(bkey_start_pos(r_k.k), POS(0, idx + sectors)))
  77                                 break;
  78
  79                         /* extent_update_to_keys(), for the reflink_v update */
  80                         *nr_iters += 1;
  81
  82                         *nr_iters += 1 + bch2_bkey_nr_alloc_ptrs(r_k);
  83
  84                         if (*nr_iters >= max_iters) {
  85                                 struct bpos pos = bkey_start_pos(k.k);
  86                                 pos.offset += min_t(u64, k.k->size,
  87                                                     r_k.k->p.offset - idx);
  88
  89                                 *end = bpos_min(*end, pos);
  90                                 ret = 1;
  91                                 break;
  92                         }
  93                 }
  94                 bch2_trans_iter_exit(trans, &iter);
  95
  96                 break;
  97         }
  98         }
  99
 100         return ret2 ?: ret;
 101 }
 102
 103 #define EXTENT_ITERS_MAX        (BTREE_ITER_INITIAL / 3)
 104
 105 int bch2_extent_atomic_end(struct btree_trans *trans,
 106                            struct btree_iter *iter,
 107                            struct bkey_i *insert,
 108                            struct bpos *end)
 109 {
 110         struct btree_iter copy;
 111         struct bkey_s_c k;
 112         unsigned nr_iters = 0;
 113         int ret;
 114
 115         ret = bch2_btree_iter_traverse(iter);
 116         if (ret)
 117                 return ret;
 118
 119         *end = insert->k.p;
 120
 121         /* extent_update_to_keys(): */
 122         nr_iters += 1;
 123
 124         ret = count_iters_for_insert(trans, bkey_i_to_s_c(insert), 0, end,
 125                                      &nr_iters, EXTENT_ITERS_MAX / 2);
 126         if (ret < 0)
 127                 return ret;
 128
 129         bch2_trans_copy_iter(&copy, iter);
 130
 131         for_each_btree_key_upto_continue_norestart(copy, insert->k.p, 0, k, ret) {
 132                 unsigned offset = 0;
 133
 134                 if (bkey_gt(bkey_start_pos(&insert->k), bkey_start_pos(k.k)))
 135                         offset = bkey_start_offset(&insert->k) -
 136                                 bkey_start_offset(k.k);
 137
 138                 /* extent_handle_overwrites(): */
 139                 switch (bch2_extent_overlap(&insert->k, k.k)) {
 140                 case BCH_EXTENT_OVERLAP_ALL:
 141                 case BCH_EXTENT_OVERLAP_FRONT:
 142                         nr_iters += 1;
 143                         break;
 144                 case BCH_EXTENT_OVERLAP_BACK:
 145                 case BCH_EXTENT_OVERLAP_MIDDLE:
 146                         nr_iters += 2;
 147                         break;
 148                 }
 149
 150                 ret = count_iters_for_insert(trans, k, offset, end,
 151                                         &nr_iters, EXTENT_ITERS_MAX);
 152                 if (ret)
 153                         break;
 154         }
 155
 156         bch2_trans_iter_exit(trans, &copy);
 157         return ret < 0 ? ret : 0;
 158 }
 159
 160 int bch2_extent_trim_atomic(struct btree_trans *trans,
 161                             struct btree_iter *iter,
 162                             struct bkey_i *k)
 163 {
 164         struct bpos end;
 165         int ret;
 166
 167         ret = bch2_extent_atomic_end(trans, iter, k, &end);
 168         if (ret)
 169                 return ret;
 170
 171         bch2_cut_back(end, k);
 172         return 0;
 173 }