From 1e7eeed28d952adf81090e9551e7ee1d5a20ac44 Mon Sep 17 00:00:00 2001 From: Hallvard Furuseth Date: Sun, 17 Aug 2014 00:29:12 +0200 Subject: [PATCH] Fix loose pages in mdb_freelist_save(). Leaving them in dirty_list caused breakage. Instead merge them into me_pghead at the end, when no more pages will be allocated. --- libraries/liblmdb/mdb.c | 66 ++++++++++++++++++++++++++--------------- 1 file changed, 42 insertions(+), 24 deletions(-) diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c index 4e23888..47a230b 100644 --- a/libraries/liblmdb/mdb.c +++ b/libraries/liblmdb/mdb.c @@ -745,7 +745,7 @@ 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 */ + /** Link in #MDB_txn.%mt_loose_pgs list */ #define NEXT_LOOSE_PAGE(p) (*(MDB_page **)((p) + 2)) /** Header for a single key/data pair within a page. @@ -950,6 +950,8 @@ struct MDB_txn { * in this transaction, linked through #NEXT_LOOSE_PAGE(page). */ MDB_page *mt_loose_pgs; + /* #Number of loose pages (#mt_loose_pgs) */ + int mt_loose_count; /** The sorted list of dirty pages we temporarily wrote to disk * because the dirty list was full. page numbers in here are * shifted left by 1, deleted slots have the LSB set. @@ -1661,6 +1663,7 @@ mdb_page_loose(MDB_cursor *mc, MDB_page *mp) mp->mp_pgno)); NEXT_LOOSE_PAGE(mp) = mc->mc_txn->mt_loose_pgs; mc->mc_txn->mt_loose_pgs = mp; + mc->mc_txn->mt_loose_count++; mp->mp_flags |= P_LOOSE; } else { int rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, pgno); @@ -1950,6 +1953,7 @@ mdb_page_alloc(MDB_cursor *mc, int num, MDB_page **mp) if (num == 1 && txn->mt_loose_pgs) { np = txn->mt_loose_pgs; txn->mt_loose_pgs = NEXT_LOOSE_PAGE(np); + txn->mt_loose_count--; DPRINTF(("db %d use loose page %"Z"u", DDBI(mc), np->mp_pgno)); *mp = np; @@ -2823,30 +2827,17 @@ mdb_freelist_save(MDB_txn *txn) return rc; } - /* Dispose of loose pages. Usually they will have all - * been used up by the time we get here. - */ - if (txn->mt_loose_pgs) { + if (!env->me_pghead) { + /* Put loose page numbers in mt_free_pgs, since + * we may be unable to return them to me_pghead. + */ MDB_page *mp = txn->mt_loose_pgs; - /* Just return them to freeDB */ - if (env->me_pghead) { - int i, j; - mop = env->me_pghead; - 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; - } - } else { - /* Oh well, they were wasted. Put on freelist */ - for (; mp; mp = NEXT_LOOSE_PAGE(mp)) { - mdb_midl_append(&txn->mt_free_pgs, mp->mp_pgno); - } - } + if ((rc = mdb_midl_need(&txn->mt_free_pgs, txn->mt_loose_count)) != 0) + return rc; + for (; mp; mp = NEXT_LOOSE_PAGE(mp)) + mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno); txn->mt_loose_pgs = NULL; + txn->mt_loose_count = 0; } /* MDB_RESERVE cancels meminit in ovpage malloc (when no WRITEMAP) */ @@ -2910,7 +2901,7 @@ mdb_freelist_save(MDB_txn *txn) } mop = env->me_pghead; - mop_len = mop ? mop[0] : 0; + mop_len = (mop ? mop[0] : 0) + txn->mt_loose_count; /* Reserve records for me_pghead[]. Split it if multi-page, * to avoid searching freeDB for a page range. Use keys in @@ -2950,6 +2941,28 @@ mdb_freelist_save(MDB_txn *txn) total_room += head_room; } + /* Return loose page numbers to me_pghead, though usually none are + * left at this point. The pages themselves remain in dirty_list. + */ + if (txn->mt_loose_pgs) { + MDB_page *mp = txn->mt_loose_pgs; + unsigned count = txn->mt_loose_count; + MDB_IDL loose; + /* Room for loose pages + temp IDL with same */ + if ((rc = mdb_midl_need(&env->me_pghead, 2*count+1)) != 0) + return rc; + mop = env->me_pghead; + loose = mop + MDB_IDL_ALLOCLEN(mop) - count; + for (count = 0; mp; mp = NEXT_LOOSE_PAGE(mp)) + loose[ ++count ] = mp->mp_pgno; + loose[0] = count; + mdb_midl_sort(loose); + mdb_midl_xmerge(mop, loose); + txn->mt_loose_pgs = NULL; + txn->mt_loose_count = 0; + mop_len = mop[0]; + } + /* Fill in the reserved me_pghead records */ rc = MDB_SUCCESS; if (mop_len) { @@ -3264,6 +3277,7 @@ mdb_txn_commit(MDB_txn *txn) for (lp = &parent->mt_loose_pgs; *lp; lp = &NEXT_LOOSE_PAGE(lp)) ; *lp = txn->mt_loose_pgs; + parent->mt_loose_count += txn->mt_loose_count; parent->mt_child = NULL; mdb_midl_free(((MDB_ntxn *)txn)->mnt_pgstate.mf_pghead); @@ -3326,6 +3340,10 @@ mdb_txn_commit(MDB_txn *txn) (rc = mdb_env_write_meta(txn))) goto fail; + /* Free P_LOOSE pages left behind in dirty_list */ + if (!(env->me_flags & MDB_WRITEMAP)) + mdb_dlist_free(txn); + done: env->me_pglast = 0; env->me_txn = NULL;