ITS#7515 Fix nested txn touch of subpage/ovpage.

mdb_page_touch(): Don't touch a subpage, replacing with non-subpage.
mdb_cursor_put(): Don't overwrite ancestor txn's dirty overflow page.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 6c7d28c6b9262aa1ac3dde60ac570ece54e92f67..acf8338ab343bb41bea39f4f5953f12be5d6712f 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -1633,7 +1633,7 @@ finish:
                        SETPGNO(NODEPTR(mc->mc_pg[mc->mc_top-1], mc->mc_ki[mc->mc_top-1]), mp->mp_pgno);
                else
                        mc->mc_db->md_root = mp->mp_pgno;
-       } else if (mc->mc_txn->mt_parent) {
+       } else if (mc->mc_txn->mt_parent && !(mp->mp_flags & P_SUBP)) {
                MDB_page *np;
                MDB_ID2 mid;
                /* If txn has a parent, make sure the page is in our
@@ -5197,11 +5197,11 @@ current:
                if (F_ISSET(leaf->mn_flags, F_BIGDATA)) {
                        MDB_page *omp;
                        pgno_t pg;
-                       int ovpages, dpages;
+                       unsigned psize = mc->mc_txn->mt_env->me_psize;
+                       int level, ovpages, dpages = OVPAGES(data->mv_size, psize);
 
-                       dpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
                        memcpy(&pg, NODEDATA(leaf), sizeof(pg));
-                       if ((rc2 = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) != 0)
+                       if ((rc2 = mdb_page_get(mc->mc_txn, pg, &omp, &level)) != 0)
                                return rc2;
                        ovpages = omp->mp_pages;
 
@@ -5211,6 +5211,28 @@ current:
                                 * bother to try shrinking the page if the new data
                                 * is smaller than the overflow threshold.
                                 */
+                               if (level > 1) {
+                                       /* It is writable only in a parent txn */
+                                       size_t sz = (size_t) psize * ovpages, off;
+                                       MDB_page *np = mdb_page_malloc(mc, ovpages);
+                                       MDB_ID2 id2;
+                                       if (!np)
+                                               return ENOMEM;
+                                       id2.mid = pg;
+                                       id2.mptr = np;
+                                       mdb_mid2l_insert(mc->mc_txn->mt_u.dirty_list, &id2);
+                                       if (!(flags & MDB_RESERVE)) {
+                                               /* Copy end of page, adjusting alignment so
+                                                * compiler may copy words instead of bytes.
+                                                */
+                                               off = (PAGEHDRSZ + data->mv_size) & -sizeof(size_t);
+                                               memcpy((size_t *)((char *)np + off),
+                                                       (size_t *)((char *)omp + off), sz - off);
+                                               sz = PAGEHDRSZ;
+                                       }
+                                       memcpy(np, omp, sz); /* Copy beginning of page */
+                                       omp = np;
+                               }
                                SETDSZ(leaf, data->mv_size);
                                if (F_ISSET(flags, MDB_RESERVE))
                                        data->mv_data = METADATA(omp);