Fix mdb_page_loose() vs. mdb_page_flush().

Do not overwrite loose pages' mp_pgno with mp_next.
mdb_page_flush() will use mp_pgno to rebuild dirty_list.

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index c21f556e08e249a5a1e2122108e6cc17f20cf9bb..c5311fab32615a6ffae76fec74a605df6ad41fa5 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -701,6 +701,9 @@ typedef struct MDB_page {
        /** The number of overflow pages needed to store the given size. */
 #define OVPAGES(size, psize)   ((PAGEHDRSZ-1 + (size)) / (psize) + 1)
 
+       /** Link in #MDB_txn.%mt_loose_pages list */
+#define NEXT_LOOSE_PAGE(p)             (*(MDB_page **)METADATA(p))
+
        /** Header for a single key/data pair within a page.
         * Used in pages of type #P_BRANCH and #P_LEAF without #P_LEAF2.
         * We guarantee 2-byte alignment for 'MDB_node's.
@@ -900,7 +903,7 @@ struct MDB_txn {
         */
        MDB_IDL         mt_free_pgs;
        /** The list of loose pages that became unused and may be reused
-        *      in this transaction.
+        *      in this transaction, linked through #NEXT_LOOSE_PAGE(page).
         */
        MDB_page        *mt_loose_pgs;
        /** The sorted list of dirty pages we temporarily wrote to disk
@@ -1569,9 +1572,7 @@ mdb_page_loose(MDB_cursor *mc, MDB_page *mp)
                }
        }
        if (loose) {
-               pgno_t *pp = (pgno_t *)mp->mp_ptrs;
-               *pp = pgno;
-               mp->mp_next = mc->mc_txn->mt_loose_pgs;
+               NEXT_LOOSE_PAGE(mp) = mc->mc_txn->mt_loose_pgs;
                mc->mc_txn->mt_loose_pgs = mp;
                mp->mp_flags |= P_LOOSE;
        } else {
@@ -1632,7 +1633,7 @@ mdb_pages_xkeep(MDB_cursor *mc, unsigned pflags, int all)
        }
 
        /* Loose pages shouldn't be spilled */
-       for (dp = txn->mt_loose_pgs; dp; dp=dp->mp_next) {
+       for (dp = txn->mt_loose_pgs; dp; dp = NEXT_LOOSE_PAGE(dp)) {
                if ((dp->mp_flags & Mask) == pflags)
                        dp->mp_flags ^= P_KEEP;
        }
@@ -1866,11 +1867,8 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp)
 
        /* If there are any loose pages, just use them */
        if (num == 1 && txn->mt_loose_pgs) {
-               pgno_t *pp;
                np = txn->mt_loose_pgs;
-               txn->mt_loose_pgs = np->mp_next;
-               pp = (pgno_t *)np->mp_ptrs;
-               np->mp_pgno = *pp;
+               txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np);
                *mp = np;
                return MDB_SUCCESS;
        }
@@ -2741,28 +2739,22 @@ mdb_freelist_save(MDB_txn *txn)
         */
        if (txn->mt_loose_pgs) {
                MDB_page *mp = txn->mt_loose_pgs;
-               pgno_t *pp;
                /* Just return them to freeDB */
                if (env->me_pghead) {
                        int i, j;
                        mop = env->me_pghead;
-                       while(mp) {
-                               pgno_t pg;
-                               pp = (pgno_t *)mp->mp_ptrs;
-                               pg = *pp;
+                       for (; mp; mp = NEXT_LOOSE_PAGE(mp)) {
+                               pgno_t pg = mp->mp_pgno;
                                j = mop[0] + 1;
                                for (i = mop[0]; i && mop[i] < pg; i--)
                                        mop[j--] = mop[i];
                                mop[j] = pg;
                                mop[0] += 1;
-                               mp = mp->mp_next;
                        }
                } else {
                /* Oh well, they were wasted. Put on freelist */
-                       while(mp) {
-                               pp = (pgno_t *)mp->mp_ptrs;
-                               mdb_midl_append(&txn->mt_free_pgs, *pp);
-                               mp = mp->mp_next;
+                       for (; mp; mp = NEXT_LOOSE_PAGE(mp)) {
+                               mdb_midl_append(&txn->mt_free_pgs, mp->mp_pgno);
                        }
                }
                txn->mt_loose_pgs = NULL;