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Cleanup, fix freelist alloc

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Don't allow new pages for free list to come from the free list.
Otherwise a nasty data self-reference occurs that is too much
trouble to unwind.
vmware
Howard Chu 13 years ago
parent f7aa0d5e4a
commit 0f459dd773
1 changed files with 110 additions and 98 deletions
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  1. 140
      libraries/libmdb/mdb.c

140
libraries/libmdb/mdb.c
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@ -268,8 +268,8 @@ typedef struct MDB_pageparent {
unsigned mp_pi; unsigned mp_pi;
} MDB_pageparent; } MDB_pageparent;
static MDB_dpage *mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num); static MDB_dpage *mdb_alloc_page(MDB_txn *txn, MDB_dbi dbi, MDB_page *parent, unsigned int parent_idx, int num);
static int mdb_touch(MDB_txn *txn, MDB_pageparent *mp); static int mdb_touch(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *mp);
typedef struct MDB_ppage { /* ordered list of pages */ typedef struct MDB_ppage { /* ordered list of pages */
MDB_page *mp_page; MDB_page *mp_page;
@ -321,7 +321,6 @@ typedef struct MDB_dbx {
struct MDB_txn { struct MDB_txn {
pgno_t mt_next_pgno; /* next unallocated page */ pgno_t mt_next_pgno; /* next unallocated page */
ULONG mt_txnid; ULONG mt_txnid;
ULONG mt_oldest;
MDB_env *mt_env; MDB_env *mt_env;
pgno_t *mt_free_pgs; /* this is an IDL */ pgno_t *mt_free_pgs; /* this is an IDL */
union { union {
@ -570,21 +569,20 @@ mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b)
/* Allocate new page(s) for writing */ /* Allocate new page(s) for writing */
static MDB_dpage * static MDB_dpage *
mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num) mdb_alloc_page(MDB_txn *txn, MDB_dbi dbi, MDB_page *parent, unsigned int parent_idx, int num)
{ {
MDB_dpage *dp; MDB_dpage *dp;
pgno_t pgno = P_INVALID; pgno_t pgno = P_INVALID;
ULONG oldest;
MIDL2 mid; MIDL2 mid;
if (txn->mt_txnid > 2) { if (txn->mt_txnid > 2) {
oldest = txn->mt_txnid - 1; if (!txn->mt_env->me_pghead && dbi != FREE_DBI &&
if (!txn->mt_env->me_pghead && txn->mt_dbs[FREE_DBI].md_root != P_INVALID) { txn->mt_dbs[FREE_DBI].md_root != P_INVALID) {
/* See if there's anything in the free DB */ /* See if there's anything in the free DB */
MDB_pageparent mpp; MDB_pageparent mpp;
MDB_node *leaf; MDB_node *leaf;
ULONG *kptr; ULONG *kptr, oldest;
mpp.mp_parent = NULL; mpp.mp_parent = NULL;
mpp.mp_pi = 0; mpp.mp_pi = 0;
@ -592,10 +590,19 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
leaf = NODEPTR(mpp.mp_page, 0); leaf = NODEPTR(mpp.mp_page, 0);
kptr = (ULONG *)NODEKEY(leaf); kptr = (ULONG *)NODEKEY(leaf);
/* It's potentially usable, unless there are still {
* older readers outstanding. Grab it. unsigned int i;
*/ oldest = txn->mt_txnid - 1;
for (i=0; i<txn->mt_env->me_txns->mti_numreaders; i++) {
ULONG mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
if (mr && mr < oldest)
oldest = mr;
}
}
if (oldest > *kptr) { if (oldest > *kptr) {
/* It's usable, grab it.
*/
MDB_oldpages *mop; MDB_oldpages *mop;
MDB_val data; MDB_val data;
pgno_t *idl; pgno_t *idl;
@ -627,16 +634,7 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
} }
} }
if (txn->mt_env->me_pghead) { if (txn->mt_env->me_pghead) {
unsigned int i;
for (i=0; i<txn->mt_env->me_txns->mti_numreaders; i++) {
ULONG mr = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
if (!mr) continue;
if (mr < oldest)
oldest = txn->mt_env->me_txns->mti_readers[i].mr_txnid;
}
if (oldest > txn->mt_env->me_pghead->mo_txnid) {
MDB_oldpages *mop = txn->mt_env->me_pghead; MDB_oldpages *mop = txn->mt_env->me_pghead;
txn->mt_oldest = oldest;
if (num > 1) { if (num > 1) {
/* FIXME: For now, always use fresh pages. We /* FIXME: For now, always use fresh pages. We
* really ought to search the free list for a * really ought to search the free list for a
@ -660,7 +658,6 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
} }
} }
} }
}
if (pgno == P_INVALID) { if (pgno == P_INVALID) {
/* DB size is maxed out */ /* DB size is maxed out */
@ -693,7 +690,7 @@ mdb_alloc_page(MDB_txn *txn, MDB_page *parent, unsigned int parent_idx, int num)
/* Touch a page: make it dirty and re-insert into tree with updated pgno. /* Touch a page: make it dirty and re-insert into tree with updated pgno.
*/ */
static int static int
mdb_touch(MDB_txn *txn, MDB_pageparent *pp) mdb_touch(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *pp)
{ {
MDB_page *mp = pp->mp_page; MDB_page *mp = pp->mp_page;
pgno_t pgno; pgno_t pgno;
@ -702,9 +699,9 @@ mdb_touch(MDB_txn *txn, MDB_pageparent *pp)
if (!F_ISSET(mp->mp_flags, P_DIRTY)) { if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
MDB_dpage *dp; MDB_dpage *dp;
if ((dp = mdb_alloc_page(txn, pp->mp_parent, pp->mp_pi, 1)) == NULL) if ((dp = mdb_alloc_page(txn, dbi, pp->mp_parent, pp->mp_pi, 1)) == NULL)
return ENOMEM; return ENOMEM;
DPRINTF("touched page %lu -> %lu", mp->mp_pgno, dp->p.mp_pgno); DPRINTF("touched db %u page %lu -> %lu", dbi, mp->mp_pgno, dp->p.mp_pgno);
assert(mp->mp_pgno != dp->p.mp_pgno); assert(mp->mp_pgno != dp->p.mp_pgno);
mdb_midl_insert(txn->mt_free_pgs, mp->mp_pgno); mdb_midl_insert(txn->mt_free_pgs, mp->mp_pgno);
pgno = dp->p.mp_pgno; pgno = dp->p.mp_pgno;
@ -740,11 +737,6 @@ mdb_txn_renew0(MDB_txn *txn)
{ {
MDB_env *env = txn->mt_env; MDB_env *env = txn->mt_env;
if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("mdb_txn_begin: environment had fatal error, must shutdown!");
return MDB_PANIC;
}
if (txn->mt_flags & MDB_TXN_RDONLY) { if (txn->mt_flags & MDB_TXN_RDONLY) {
MDB_reader *r = pthread_getspecific(env->me_txkey); MDB_reader *r = pthread_getspecific(env->me_txkey);
if (!r) { if (!r) {
@ -795,10 +787,6 @@ mdb_txn_renew0(MDB_txn *txn)
(txn->mt_numdbs - 2) * sizeof(MDB_db)); (txn->mt_numdbs - 2) * sizeof(MDB_db));
LAZY_RWLOCK_UNLOCK(&env->me_dblock); LAZY_RWLOCK_UNLOCK(&env->me_dblock);
DPRINTF("begin txn %p %lu%c on mdbenv %p, root page %lu", txn,
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w',
(void *) env, txn->mt_dbs[MAIN_DBI].md_root);
return MDB_SUCCESS; return MDB_SUCCESS;
} }
@ -810,10 +798,15 @@ mdb_txn_renew(MDB_txn *txn)
if (!txn) if (!txn)
return EINVAL; return EINVAL;
if (txn->mt_env->me_flags & MDB_FATAL_ERROR) {
DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC;
}
rc = mdb_txn_renew0(txn); rc = mdb_txn_renew0(txn);
if (rc == MDB_SUCCESS) { if (rc == MDB_SUCCESS) {
DPRINTF("reset txn %p %lu%c on mdbenv %p, root page %lu", txn, DPRINTF("renew txn %lu%c %p on mdbenv %p, root page %lu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn,
(void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root); (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
} }
return rc; return rc;
@ -826,7 +819,7 @@ mdb_txn_begin(MDB_env *env, int rdonly, MDB_txn **ret)
int rc; int rc;
if (env->me_flags & MDB_FATAL_ERROR) { if (env->me_flags & MDB_FATAL_ERROR) {
DPUTS("mdb_txn_begin: environment had fatal error, must shutdown!"); DPUTS("environment had fatal error, must shutdown!");
return MDB_PANIC; return MDB_PANIC;
} }
if ((txn = calloc(1, sizeof(MDB_txn) + env->me_maxdbs * sizeof(MDB_db))) == NULL) { if ((txn = calloc(1, sizeof(MDB_txn) + env->me_maxdbs * sizeof(MDB_db))) == NULL) {
@ -844,8 +837,8 @@ mdb_txn_begin(MDB_env *env, int rdonly, MDB_txn **ret)
free(txn); free(txn);
else { else {
*ret = txn; *ret = txn;
DPRINTF("begin txn %p %lu%c on mdbenv %p, root page %lu", txn, DPRINTF("begin txn %lu%c %p on mdbenv %p, root page %lu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn,
(void *) env, txn->mt_dbs[MAIN_DBI].md_root); (void *) env, txn->mt_dbs[MAIN_DBI].md_root);
} }
@ -894,8 +887,8 @@ mdb_txn_reset(MDB_txn *txn)
if (txn == NULL) if (txn == NULL)
return; return;
DPRINTF("reset txn %p %lu%c on mdbenv %p, root page %lu", txn, DPRINTF("reset txn %lu%c %p on mdbenv %p, root page %lu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn,
(void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root); (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_txn_reset0(txn); mdb_txn_reset0(txn);
@ -907,8 +900,8 @@ mdb_txn_abort(MDB_txn *txn)
if (txn == NULL) if (txn == NULL)
return; return;
DPRINTF("abort txn %p %lu%c on mdbenv %p, root page %lu", txn, DPRINTF("abort txn %lu%c %p on mdbenv %p, root page %lu",
txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn->mt_txnid, (txn->mt_flags & MDB_TXN_RDONLY) ? 'r' : 'w', txn,
(void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root); (void *)txn->mt_env, txn->mt_dbs[MAIN_DBI].md_root);
mdb_txn_reset0(txn); mdb_txn_reset0(txn);
@ -952,27 +945,23 @@ mdb_txn_commit(MDB_txn *txn)
if (!txn->mt_u.dirty_list[0].mid) if (!txn->mt_u.dirty_list[0].mid)
goto done; goto done;
DPRINTF("committing txn %p %lu on mdbenv %p, root page %lu", txn, DPRINTF("committing txn %lu %p on mdbenv %p, root page %lu",
txn->mt_txnid, (void *) env, txn->mt_dbs[MAIN_DBI].md_root); txn->mt_txnid, txn, (void *)env, txn->mt_dbs[MAIN_DBI].md_root);
/* should only be one record now */ /* should only be one record now */
if (env->me_pghead) { if (env->me_pghead) {
MDB_val key, data; MDB_pageparent mpp;
MDB_oldpages *mop;
mop = env->me_pghead; /* make sure first page of freeDB is touched and on freelist */
key.mv_size = sizeof(pgno_t); mpp.mp_parent = NULL;
key.mv_data = (char *)&mop->mo_txnid; mpp.mp_pi = 0;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages); mdb_search_page(txn, FREE_DBI, NULL, NULL, 1, &mpp);
data.mv_data = mop->mo_pages;
mdb_put0(txn, FREE_DBI, &key, &data, 0);
free(env->me_pghead);
env->me_pghead = NULL;
} }
/* save to free list */ /* save to free list */
if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) { if (!MDB_IDL_IS_ZERO(txn->mt_free_pgs)) {
MDB_val key, data; MDB_val key, data;
MDB_pageparent mpp; MDB_pageparent mpp;
ULONG i;
/* make sure last page of freeDB is touched and on freelist */ /* make sure last page of freeDB is touched and on freelist */
key.mv_size = MAXKEYSIZE+1; key.mv_size = MAXKEYSIZE+1;
@ -995,9 +984,34 @@ mdb_txn_commit(MDB_txn *txn)
/* write to last page of freeDB */ /* write to last page of freeDB */
key.mv_size = sizeof(pgno_t); key.mv_size = sizeof(pgno_t);
key.mv_data = (char *)&txn->mt_txnid; key.mv_data = (char *)&txn->mt_txnid;
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
data.mv_data = txn->mt_free_pgs; data.mv_data = txn->mt_free_pgs;
/* The free list can still grow during this call,
* despite the pre-emptive touches above. So check
* and make sure the entire thing got written.
*/
do {
i = txn->mt_free_pgs[0];
data.mv_size = MDB_IDL_SIZEOF(txn->mt_free_pgs);
rc = mdb_put0(txn, FREE_DBI, &key, &data, 0);
if (rc) {
mdb_txn_abort(txn);
return rc;
}
} while (i != txn->mt_free_pgs[0]);
}
/* should only be one record now */
if (env->me_pghead) {
MDB_val key, data;
MDB_oldpages *mop;
mop = env->me_pghead;
key.mv_size = sizeof(pgno_t);
key.mv_data = (char *)&mop->mo_txnid;
data.mv_size = MDB_IDL_SIZEOF(mop->mo_pages);
data.mv_data = mop->mo_pages;
mdb_put0(txn, FREE_DBI, &key, &data, 0); mdb_put0(txn, FREE_DBI, &key, &data, 0);
free(env->me_pghead);
env->me_pghead = NULL;
} }
/* Update DB root pointers. Their pages have already been /* Update DB root pointers. Their pages have already been
@ -1819,7 +1833,7 @@ mdb_search_page_root(MDB_txn *txn, MDB_dbi dbi, MDB_val *key,
if (modify) { if (modify) {
MDB_dhead *dh = ((MDB_dhead *)mp)-1; MDB_dhead *dh = ((MDB_dhead *)mp)-1;
if ((rc = mdb_touch(txn, mpp)) != 0) if ((rc = mdb_touch(txn, dbi, mpp)) != 0)
return rc; return rc;
dh = ((MDB_dhead *)mpp->mp_page)-1; dh = ((MDB_dhead *)mpp->mp_page)-1;
dh->md_parent = mpp->mp_parent; dh->md_parent = mpp->mp_parent;
@ -1888,7 +1902,7 @@ mdb_search_page(MDB_txn *txn, MDB_dbi dbi, MDB_val *key,
if (!F_ISSET(mpp->mp_page->mp_flags, P_DIRTY)) { if (!F_ISSET(mpp->mp_page->mp_flags, P_DIRTY)) {
mpp->mp_parent = NULL; mpp->mp_parent = NULL;
mpp->mp_pi = 0; mpp->mp_pi = 0;
if ((rc = mdb_touch(txn, mpp))) if ((rc = mdb_touch(txn, dbi, mpp)))
return rc; return rc;
txn->mt_dbs[dbi].md_root = mpp->mp_page->mp_pgno; txn->mt_dbs[dbi].md_root = mpp->mp_page->mp_pgno;
} }
@ -2475,7 +2489,7 @@ mdb_new_page(MDB_txn *txn, MDB_dbi dbi, uint32_t flags, int num)
{ {
MDB_dpage *dp; MDB_dpage *dp;
if ((dp = mdb_alloc_page(txn, NULL, 0, num)) == NULL) if ((dp = mdb_alloc_page(txn, dbi, NULL, 0, num)) == NULL)
return NULL; return NULL;
DPRINTF("allocated new mpage %lu, page size %u", DPRINTF("allocated new mpage %lu, page size %u",
dp->p.mp_pgno, txn->mt_env->me_psize); dp->p.mp_pgno, txn->mt_env->me_psize);
@ -2728,7 +2742,6 @@ mdb_xcursor_init1(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx, MDB_page *mp, MDB_
mx->mx_dbxs[dbn].md_name.mv_data = NODEKEY(node); mx->mx_dbxs[dbn].md_name.mv_data = NODEKEY(node);
mx->mx_dbxs[dbn].md_name.mv_size = node->mn_ksize; mx->mx_dbxs[dbn].md_name.mv_size = node->mn_ksize;
mx->mx_txn.mt_next_pgno = txn->mt_next_pgno; mx->mx_txn.mt_next_pgno = txn->mt_next_pgno;
mx->mx_txn.mt_oldest = txn->mt_oldest;
mx->mx_txn.mt_u = txn->mt_u; mx->mx_txn.mt_u = txn->mt_u;
mx->mx_cursor.mc_initialized = 0; mx->mx_cursor.mc_initialized = 0;
mx->mx_cursor.mc_eof = 0; mx->mx_cursor.mc_eof = 0;
@ -2738,7 +2751,6 @@ static void
mdb_xcursor_fini(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx) mdb_xcursor_fini(MDB_txn *txn, MDB_dbi dbi, MDB_xcursor *mx)
{ {
txn->mt_next_pgno = mx->mx_txn.mt_next_pgno; txn->mt_next_pgno = mx->mx_txn.mt_next_pgno;
txn->mt_oldest = mx->mx_txn.mt_oldest;
txn->mt_u = mx->mx_txn.mt_u; txn->mt_u = mx->mx_txn.mt_u;
txn->mt_dbs[0] = mx->mx_dbs[0]; txn->mt_dbs[0] = mx->mx_dbs[0];
txn->mt_dbs[1] = mx->mx_dbs[1]; txn->mt_dbs[1] = mx->mx_dbs[1];
@ -2870,8 +2882,8 @@ mdb_move_node(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *src, indx_t srcindx,
DKBUF; DKBUF;
/* Mark src and dst as dirty. */ /* Mark src and dst as dirty. */
if ((rc = mdb_touch(txn, src)) || if ((rc = mdb_touch(txn, dbi, src)) ||
(rc = mdb_touch(txn, dst))) (rc = mdb_touch(txn, dbi, dst)))
return rc;; return rc;;
if (IS_LEAF2(src->mp_page)) { if (IS_LEAF2(src->mp_page)) {
@ -2964,8 +2976,8 @@ mdb_merge(MDB_txn *txn, MDB_dbi dbi, MDB_pageparent *src, MDB_pageparent *dst)
assert(dst->mp_parent); assert(dst->mp_parent);
/* Mark src and dst as dirty. */ /* Mark src and dst as dirty. */
if ((rc = mdb_touch(txn, src)) || if ((rc = mdb_touch(txn, dbi, src)) ||
(rc = mdb_touch(txn, dst))) (rc = mdb_touch(txn, dbi, dst)))
return rc; return rc;
/* Move all nodes from src to dst. /* Move all nodes from src to dst.

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