bcachefs: More fixes for counting extent update iterators

This is unfortunately really fragile - hopefully we'll be able to think
of a new approach at some point.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/fs/bcachefs/extent_update.c b/fs/bcachefs/extent_update.c
index 2a7d913bdda3f053d6df6612f9a37ecc7408a404..d0af1bc17018ad2c8c56a9fa9aa9cda1a655b30e 100644 (file)
--- a/fs/bcachefs/extent_update.c
+++ b/fs/bcachefs/extent_update.c
@@ -34,16 +34,10 @@ static int count_iters_for_insert(struct btree_trans *trans,
                                  unsigned offset,
                                  struct bpos *end,
                                  unsigned *nr_iters,
-                                 unsigned max_iters,
-                                 bool overwrite)
+                                 unsigned max_iters)
 {
-       int ret = 0;
+       int ret = 0, ret2 = 0;
 
-       /*
-        * The extent update path requires an _additional_ iterator for each
-        * extent we're inserting and overwriting:
-        */
-       *nr_iters += 1;
        if (*nr_iters >= max_iters) {
                *end = bpos_min(*end, k.k->p);
                ret = 1;
@@ -70,11 +64,14 @@ static int count_iters_for_insert(struct btree_trans *trans,
 
                for_each_btree_key(trans, iter,
                                   BTREE_ID_REFLINK, POS(0, idx + offset),
-                                  BTREE_ITER_SLOTS, r_k, ret) {
+                                  BTREE_ITER_SLOTS, r_k, ret2) {
                        if (bkey_cmp(bkey_start_pos(r_k.k),
                                     POS(0, idx + sectors)) >= 0)
                                break;
 
+                       /* extent_update_to_keys(), for the reflink_v update */
+                       *nr_iters += 1;
+
                        *nr_iters += 1 + bch2_bkey_nr_alloc_ptrs(r_k);
 
                        if (*nr_iters >= max_iters) {
@@ -92,7 +89,7 @@ static int count_iters_for_insert(struct btree_trans *trans,
        }
        }
 
-       return ret;
+       return ret2 ?: ret;
 }
 
 #define EXTENT_ITERS_MAX       (BTREE_ITER_MAX / 3)
@@ -121,8 +118,11 @@ int bch2_extent_atomic_end(struct btree_iter *iter,
 
        *end = bpos_min(insert->k.p, b->key.k.p);
 
+       /* extent_update_to_keys(): */
+       nr_iters += 1;
+
        ret = count_iters_for_insert(trans, bkey_i_to_s_c(insert), 0, end,
-                                    &nr_iters, EXTENT_ITERS_MAX / 2, false);
+                                    &nr_iters, EXTENT_ITERS_MAX / 2);
        if (ret < 0)
                return ret;
 
@@ -139,8 +139,20 @@ int bch2_extent_atomic_end(struct btree_iter *iter,
                        offset = bkey_start_offset(&insert->k) -
                                bkey_start_offset(k.k);
 
+               /* extent_handle_overwrites(): */
+               switch (bch2_extent_overlap(&insert->k, k.k)) {
+               case BCH_EXTENT_OVERLAP_ALL:
+               case BCH_EXTENT_OVERLAP_FRONT:
+                       nr_iters += 1;
+                       break;
+               case BCH_EXTENT_OVERLAP_BACK:
+               case BCH_EXTENT_OVERLAP_MIDDLE:
+                       nr_iters += 2;
+                       break;
+               }
+
                ret = count_iters_for_insert(trans, k, offset, end,
-                                       &nr_iters, EXTENT_ITERS_MAX, true);
+                                       &nr_iters, EXTENT_ITERS_MAX);
                if (ret)
                        break;