More for ITS#7620 Fix mdb_ovpage_free().

Do not binary-search dirty_list, it is unsorted when MDB_WRITEMAP.
Catch errors. In nested txns, put the page in mt_free_pgs after
all since pages dirty in a parent txn would add complexities.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index 2f6a02735f516b10436a87d436b5b4664e6cfdb2..536aaaaff5feb24341ecfb85f0fcfd3e55a8d379 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -4281,47 +4281,55 @@ mdb_page_search(MDB_cursor *mc, MDB_val *key, int flags)
 static int
 mdb_ovpage_free(MDB_cursor *mc, MDB_page *mp)
 {
+       MDB_txn *txn = mc->mc_txn;
        pgno_t pg = mp->mp_pgno;
        unsigned i, ovpages = mp->mp_pages;
        int rc;
 
        DPRINTF("free ov page %zu (%d)", pg, ovpages);
-       mc->mc_db->md_overflow_pages -= ovpages;
        /* If the page is dirty we just acquired it, so we should
         * give it back to our current free list, if any.
+        * Not currently supported in nested txns.
         * Otherwise put it onto the list of pages we freed in this txn.
         */
-       if ((mp->mp_flags & P_DIRTY) && mc->mc_txn->mt_env->me_pghead) {
+       if ((mp->mp_flags & P_DIRTY) && !txn->mt_parent && txn->mt_env->me_pghead) {
                unsigned j, x;
-               pgno_t *mop = mc->mc_txn->mt_env->me_pghead;
-               /* Remove from dirty list */
-               x = mdb_mid2l_search(mc->mc_txn->mt_u.dirty_list, pg);
-               for (; x < mc->mc_txn->mt_u.dirty_list[0].mid; x++)
-                       mc->mc_txn->mt_u.dirty_list[x] = mc->mc_txn->mt_u.dirty_list[x+1];
-               mc->mc_txn->mt_u.dirty_list[0].mid--;
-               /* Make room to insert pg */
+               pgno_t *mop = txn->mt_env->me_pghead;
+               MDB_ID2 *dl, ix, iy;
+               /* Prepare to insert pg */
                j = mop[0] + ovpages;
                if (j > mop[-1]) {
                        rc = mdb_midl_grow(&mop, ovpages);
                        if (rc)
                                return rc;
-                       mc->mc_txn->mt_env->me_pghead = mop;
+                       txn->mt_env->me_pghead = mop;
                }
-               for (i = mop[0]; i>0; i--) {
-                       if (mop[i] < pg)
-                               mop[j--] = mop[i];
-                       else
-                               break;
+               /* Remove from dirty list */
+               dl = txn->mt_u.dirty_list;
+               x = dl[0].mid--;
+               for (ix = dl[x]; ix.mid != pg; ix = iy) {
+                       if (x > 1) {
+                               x--;
+                               iy = dl[x];
+                               dl[x] = ix;
+                       } else {
+                               assert(x > 1);
+                               return MDB_CORRUPTED;
+                       }
                }
+               /* Insert in me_pghead */
+               for (i = mop[0]; i && mop[i] < pg; i--)
+                       mop[j--] = mop[i];
                while (j>i)
                        mop[j--] = pg++;
                mop[0] += ovpages;
        } else {
                for (i=0; i<ovpages; i++) {
-                       mdb_midl_append(&mc->mc_txn->mt_free_pgs, pg);
+                       mdb_midl_append(&txn->mt_free_pgs, pg);
                        pg++;
                }
        }
+       mc->mc_db->md_overflow_pages -= ovpages;
        return 0;
 }