diff options
Diffstat (limited to 'src/third_party/wiredtiger/src/btree/bt_split.c')
| -rw-r--r-- | src/third_party/wiredtiger/src/btree/bt_split.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/src/third_party/wiredtiger/src/btree/bt_split.c b/src/third_party/wiredtiger/src/btree/bt_split.c index 4f16a290958..00bea5a6773 100644 --- a/src/third_party/wiredtiger/src/btree/bt_split.c +++ b/src/third_party/wiredtiger/src/btree/bt_split.c @@ -298,7 +298,7 @@ static int __split_ref_move(WT_SESSION_IMPL *session, WT_PAGE *from_home, WT_REF **from_refp, size_t *decrp, WT_REF **to_refp, size_t *incrp) { - WT_ADDR *addr; + WT_ADDR *addr, *ref_addr; WT_CELL_UNPACK unpack; WT_DECL_RET; WT_IKEY *ikey; @@ -345,13 +345,18 @@ __split_ref_move(WT_SESSION_IMPL *session, WT_PAGE *from_home, } /* - * If there's no address (the page has never been written), or the - * address has been instantiated, there's no work to do. Otherwise, - * instantiate the address in-memory, from the on-page cell. + * If there's no address at all (the page has never been written), or + * the address has already been instantiated, there's no work to do. + * Otherwise, the address still references a split page on-page cell, + * instantiate it. We can race with reconciliation and/or eviction of + * the child pages, be cautious: read the address and verify it, and + * only update it if the value is unchanged from the original. In the + * case of a race, the address must no longer reference the split page, + * we're done. */ - addr = ref->addr; - if (addr != NULL && !__wt_off_page(from_home, addr)) { - __wt_cell_unpack((WT_CELL *)ref->addr, &unpack); + WT_ORDERED_READ(ref_addr, ref->addr); + if (ref_addr != NULL && !__wt_off_page(from_home, ref_addr)) { + __wt_cell_unpack((WT_CELL *)ref_addr, &unpack); WT_RET(__wt_calloc_one(session, &addr)); if ((ret = __wt_strndup( session, unpack.data, unpack.size, &addr->addr)) != 0) { @@ -371,7 +376,10 @@ __split_ref_move(WT_SESSION_IMPL *session, WT_PAGE *from_home, break; WT_ILLEGAL_VALUE(session); } - ref->addr = addr; + if (!__wt_atomic_cas_ptr(&ref->addr, ref_addr, addr)) { + __wt_free(session, addr->addr); + __wt_free(session, addr); + } } /* And finally, copy the WT_REF pointer itself. */ |