15 files changed, 9452 insertions, 0 deletions

diff --git a/mp/mp_alloc.c b/mp/mp_alloc.c
new file mode 100644
index 0000000..ff02143
--- /dev/null
+++ b/mp/mp_alloc.c
@@ -0,0 +1,622 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+/*
+ * __memp_alloc --
+ *	Allocate some space from a cache region.
+ *
+ * PUBLIC: int __memp_alloc __P((DB_MPOOL *,
+ * PUBLIC:     REGINFO *, MPOOLFILE *, size_t, roff_t *, void *));
+ */
+int
+__memp_alloc(dbmp, infop, mfp, len, offsetp, retp)
+	DB_MPOOL *dbmp;
+	REGINFO *infop;
+	MPOOLFILE *mfp;
+	size_t len;
+	roff_t *offsetp;
+	void *retp;
+{
+	BH *bhp, *current_bhp, *mvcc_bhp, *oldest_bhp;
+	BH_FROZEN_PAGE *frozen_bhp;
+	DB_LSN vlsn;
+	DB_MPOOL_HASH *dbht, *hp, *hp_end, *hp_saved, *hp_tmp;
+	ENV *env;
+	MPOOL *c_mp;
+	MPOOLFILE *bh_mfp;
+	size_t freed_space;
+	u_int32_t buckets, buffers, high_priority, priority, priority_saved;
+	u_int32_t put_counter, total_buckets;
+	int aggressive, alloc_freeze, b_lock, giveup, got_oldest;
+	int h_locked, need_free, need_freeze, obsolete, ret;
+	u_int8_t *endp;
+	void *p;
+
+	env = dbmp->env;
+	c_mp = infop->primary;
+	dbht = R_ADDR(infop, c_mp->htab);
+	hp_end = &dbht[c_mp->htab_buckets];
+	hp_saved = NULL;
+	priority_saved = 0;
+
+	buckets = buffers = put_counter = total_buckets = 0;
+	aggressive = alloc_freeze = giveup = got_oldest = h_locked = 0;
+
+	STAT(c_mp->stat.st_alloc++);
+
+	/*
+	 * If we're allocating a buffer, and the one we're discarding is the
+	 * same size, we don't want to waste the time to re-integrate it into
+	 * the shared memory free list.  If the DB_MPOOLFILE argument isn't
+	 * NULL, we'll compare the underlying page sizes of the two buffers
+	 * before free-ing and re-allocating buffers.
+	 */
+	if (mfp != NULL) {
+		len = SSZA(BH, buf) + mfp->stat.st_pagesize;
+		/* Add space for alignment padding for MVCC diagnostics. */
+		MVCC_BHSIZE(mfp, len);
+	}
+
+	MPOOL_REGION_LOCK(env, infop);
+
+	/*
+	 * Anything newer than 1/10th of the buffer pool is ignored during
+	 * allocation (unless allocation starts failing).
+	 */
+	high_priority = c_mp->lru_count - c_mp->stat.st_pages / 10;
+
+	/*
+	 * First we try to allocate from free memory.  If that fails, scan the
+	 * buffer pool to find buffers with low priorities.  We consider small
+	 * sets of hash buckets each time to limit the amount of work needing
+	 * to be done.  This approximates LRU, but not very well.  We either
+	 * find a buffer of the same size to use, or we will free 3 times what
+	 * we need in the hopes it will coalesce into a contiguous chunk of the
+	 * right size.  In the latter case we branch back here and try again.
+	 */
+alloc:	if ((ret = __env_alloc(infop, len, &p)) == 0) {
+		if (mfp != NULL) {
+			/*
+			 * For MVCC diagnostics, align the pointer so that the
+			 * buffer starts on a page boundary.
+			 */
+			MVCC_BHALIGN(p);
+			bhp = (BH *)p;
+
+			if ((ret = __mutex_alloc(env, MTX_MPOOL_BH,
+			    DB_MUTEX_SHARED, &bhp->mtx_buf)) != 0) {
+				MVCC_BHUNALIGN(bhp);
+				__env_alloc_free(infop, bhp);
+				goto search;
+			}
+			c_mp->stat.st_pages++;
+		}
+		MPOOL_REGION_UNLOCK(env, infop);
+found:		if (offsetp != NULL)
+			*offsetp = R_OFFSET(infop, p);
+		*(void **)retp = p;
+
+		/*
+		 * Update the search statistics.
+		 *
+		 * We're not holding the region locked here, these statistics
+		 * can't be trusted.
+		 */
+#ifdef HAVE_STATISTICS
+		total_buckets += buckets;
+		if (total_buckets != 0) {
+			if (total_buckets > c_mp->stat.st_alloc_max_buckets)
+				c_mp->stat.st_alloc_max_buckets = total_buckets;
+			c_mp->stat.st_alloc_buckets += total_buckets;
+		}
+		if (buffers != 0) {
+			if (buffers > c_mp->stat.st_alloc_max_pages)
+				c_mp->stat.st_alloc_max_pages = buffers;
+			c_mp->stat.st_alloc_pages += buffers;
+		}
+#endif
+		return (0);
+	} else if (giveup || c_mp->stat.st_pages == 0) {
+		MPOOL_REGION_UNLOCK(env, infop);
+
+		__db_errx(env,
+		    "unable to allocate space from the buffer cache");
+		return (ret);
+	}
+search:	ret = 0;
+
+	/*
+	 * We re-attempt the allocation every time we've freed 3 times what
+	 * we need.  Reset our free-space counter.
+	 */
+	freed_space = 0;
+	total_buckets += buckets;
+	buckets = 0;
+
+	/*
+	 * Walk the hash buckets and find the next two with potentially useful
+	 * buffers.  Free the buffer with the lowest priority from the buckets'
+	 * chains.
+	 */
+	for (;;) {
+		/* All pages have been freed, make one last try */
+		if (c_mp->stat.st_pages == 0)
+			goto alloc;
+
+		/* Check for wrap around. */
+		hp = &dbht[c_mp->last_checked++];
+		if (hp >= hp_end) {
+			c_mp->last_checked = 0;
+			hp = &dbht[c_mp->last_checked++];
+		}
+
+		/*
+		 * The failure mode is when there are too many buffers we can't
+		 * write or there's not enough memory in the system to support
+		 * the number of pinned buffers.
+		 *
+		 * Get aggressive if we've reviewed the entire cache without
+		 * freeing the needed space.  (The code resets "aggressive"
+		 * when we free any space.)  Aggressive means:
+		 *
+		 * a: set a flag to attempt to flush high priority buffers as
+		 *    well as other buffers.
+		 * b: sync the mpool to force out queue extent pages.  While we
+		 *    might not have enough space for what we want and flushing
+		 *    is expensive, why not?
+		 * c: look at a buffer in every hash bucket rather than choose
+		 *    the more preferable of two.
+		 * d: start to think about giving up.
+		 *
+		 * If we get here twice, sleep for a second, hopefully someone
+		 * else will run and free up some memory.
+		 *
+		 * Always try to allocate memory too, in case some other thread
+		 * returns its memory to the region.
+		 *
+		 * We don't have any way to know an allocation has no way to
+		 * succeed.  Fail if no pages are returned to the cache after
+		 * we've been trying for a relatively long time.
+		 *
+		 * !!!
+		 * This test ignores pathological cases like no buffers in the
+		 * system -- we check for that early on, so it isn't possible.
+		 */
+		if (buckets++ == c_mp->htab_buckets) {
+			if (freed_space > 0)
+				goto alloc;
+			MPOOL_REGION_UNLOCK(env, infop);
+
+			switch (++aggressive) {
+			case 1:
+				break;
+			case 2:
+				put_counter = c_mp->put_counter;
+				/* FALLTHROUGH */
+			case 3:
+			case 4:
+			case 5:
+			case 6:
+				(void)__memp_sync_int(
+				    env, NULL, 0, DB_SYNC_ALLOC, NULL, NULL);
+
+				__os_yield(env, 1, 0);
+				break;
+			default:
+				aggressive = 1;
+				if (put_counter == c_mp->put_counter)
+					giveup = 1;
+				break;
+			}
+
+			MPOOL_REGION_LOCK(env, infop);
+			goto alloc;
+		}
+
+		/*
+		 * Skip empty buckets.
+		 *
+		 * We can check for empty buckets before locking the hash
+		 * bucket as we only care if the pointer is zero or non-zero.
+		 */
+		if (SH_TAILQ_FIRST(&hp->hash_bucket, __bh) == NULL)
+			continue;
+
+		/* Unlock the region and lock the hash bucket. */
+		MPOOL_REGION_UNLOCK(env, infop);
+		MUTEX_READLOCK(env, hp->mtx_hash);
+		h_locked = 1;
+		b_lock = 0;
+
+		/*
+		 * Find a buffer we can use.
+		 *
+		 * We don't want to free a buffer out of the middle of an MVCC
+		 * chain (that requires I/O).  So, walk the buffers, looking
+		 * for, in order of preference:
+		 *
+		 *	an obsolete buffer at the end of an MVCC chain,
+		 *	the lowest priority buffer, if it is not frozen,
+		 *	the lowest priority frozen buffer.
+		 *
+		 * We use an obsolete buffer at the end of a chain as soon as
+		 * we find one.  We use the lowest-LRU singleton buffer if we
+		 * find one and it's better than the result of another hash
+		 * bucket we've reviewed.  We do not use a buffer which
+		 * has a priority greater than high_priority unless we are
+		 * being aggressive.
+		 *
+		 * We prefer ordinary buffers over frozen buffers in the middle
+		 * of an MVCC chain, regardless of priority: if the oldest
+		 * buffer in a chain is frozen, we thaw or free it before
+		 * recycling any buffers within the version chain.
+		 *
+		 * Ignore referenced buffers, we can't get rid of them.
+		 */
+retry_search:	bhp = NULL;
+		obsolete = 0;
+		SH_TAILQ_FOREACH(current_bhp, &hp->hash_bucket, hq, __bh) {
+			if (SH_CHAIN_SINGLETON(current_bhp, vc)) {
+				if (BH_REFCOUNT(current_bhp) == 0 &&
+				    (aggressive ||
+				    current_bhp->priority < high_priority) &&
+				    (bhp == NULL ||
+				    bhp->priority > current_bhp->priority)) {
+					if (bhp != NULL)
+						atomic_dec(env, &bhp->ref);
+					bhp = current_bhp;
+					atomic_inc(env, &bhp->ref);
+				}
+				continue;
+			}
+
+			for (mvcc_bhp = oldest_bhp = current_bhp;
+			    mvcc_bhp != NULL;
+			    oldest_bhp = mvcc_bhp,
+			    mvcc_bhp = SH_CHAIN_PREV(mvcc_bhp, vc, __bh)) {
+				DB_ASSERT(env, mvcc_bhp !=
+				    SH_CHAIN_PREV(mvcc_bhp, vc, __bh));
+				if (aggressive > 2 &&
+				    BH_REFCOUNT(mvcc_bhp) == 0 &&
+				    !F_ISSET(mvcc_bhp, BH_FROZEN) &&
+				    (bhp == NULL ||
+				    bhp->priority > mvcc_bhp->priority)) {
+					if (bhp != NULL)
+						atomic_dec(env, &bhp->ref);
+					bhp = mvcc_bhp;
+					atomic_inc(env, &bhp->ref);
+				}
+			}
+
+			/*
+			 * oldest_bhp is the last buffer on the MVCC chain, and
+			 * an obsolete buffer at the end of the MVCC chain
+			 * gets used without further search.
+			 *
+			 * If the buffer isn't obsolete with respect to the
+			 * cached old reader LSN, recalculate the oldest
+			 * reader LSN and check again.
+			 */
+retry_obsolete:		if (BH_OBSOLETE(oldest_bhp, hp->old_reader, vlsn)) {
+				obsolete = 1;
+				if (bhp != NULL)
+					atomic_dec(env, &bhp->ref);
+				bhp = oldest_bhp;
+				atomic_inc(env, &bhp->ref);
+				goto this_buffer;
+			}
+			if (!got_oldest) {
+				if ((ret = __txn_oldest_reader(
+				    env, &hp->old_reader)) != 0)
+					return (ret);
+				got_oldest = 1;
+				goto retry_obsolete;
+			}
+		}
+
+		/*
+		 * bhp is either NULL or the best candidate buffer.
+		 * We'll use the chosen buffer only if we have compared its
+		 * priority against one chosen from another hash bucket.
+		 */
+		if (bhp == NULL)
+			goto next_hb;
+
+		/* Adjust the priority if the bucket has not been reset. */
+		priority = bhp->priority;
+		if (c_mp->lru_reset != 0 && c_mp->lru_reset <= hp - dbht)
+			priority -= MPOOL_BASE_DECREMENT;
+
+		/*
+		 * Compare two hash buckets and select the one with the lowest
+		 * priority.  Performance testing shows looking at two improves
+		 * the LRU-ness and looking at more only does a little better.
+		 */
+		if (hp_saved == NULL) {
+			hp_saved = hp;
+			priority_saved = priority;
+			goto next_hb;
+		}
+
+		/*
+		 * If the buffer we just found is a better choice than our
+		 * previous choice, use it.
+		 *
+		 * If the previous choice was better, pretend we're moving
+		 * from this hash bucket to the previous one and re-do the
+		 * search.
+		 *
+		 * We don't worry about simply swapping between two buckets
+		 * because that could only happen if a buffer was removed
+		 * from the chain, or its priority updated.   If a buffer
+		 * is removed from the chain, some other thread has managed
+		 * to discard a buffer, so we're moving forward.  Updating
+		 * a buffer's priority will make it a high-priority buffer,
+		 * so we'll ignore it when we search again, and so we will
+		 * eventually zero in on a buffer to use, or we'll decide
+		 * there are no buffers we can use.
+		 *
+		 * If there's only a single hash bucket with buffers, we'll
+		 * search the bucket once, choose a buffer, walk the entire
+		 * list of buckets and search it again.   In the case of a
+		 * system that's busy, it's possible to imagine a case where
+		 * we'd loop for a long while.  For that reason, and because
+		 * the test is easy, we special case and test for it.
+		 */
+		if (priority > priority_saved && hp != hp_saved) {
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+			hp_tmp = hp_saved;
+			hp_saved = hp;
+			hp = hp_tmp;
+			priority_saved = priority;
+			MUTEX_READLOCK(env, hp->mtx_hash);
+			h_locked = 1;
+			DB_ASSERT(env, BH_REFCOUNT(bhp) > 0);
+			atomic_dec(env, &bhp->ref);
+			goto retry_search;
+		}
+
+this_buffer:	buffers++;
+
+		/*
+		 * Discard any previously remembered hash bucket, we've got
+		 * a winner.
+		 */
+		hp_saved = NULL;
+
+		/* Drop the hash mutex and lock the buffer exclusively. */
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		h_locked = 0;
+		/* We cannot block as the caller is probably holding locks. */
+		if (BH_REFCOUNT(bhp) > 1 ||
+		    (ret = MUTEX_TRYLOCK(env, bhp->mtx_buf)) != 0) {
+			if (ret != 0 && ret != DB_LOCK_NOTGRANTED)
+				return (ret);
+			ret = 0;
+			goto next_hb;
+		}
+		F_SET(bhp, BH_EXCLUSIVE);
+		b_lock = 1;
+
+		/* Someone may have grabbed it while we got the lock. */
+		if (BH_REFCOUNT(bhp) != 1)
+			goto next_hb;
+
+		/* Find the associated MPOOLFILE. */
+		bh_mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+
+		/* If the page is dirty, write it. */
+		ret = 0;
+		if (F_ISSET(bhp, BH_DIRTY)) {
+			DB_ASSERT(env, atomic_read(&hp->hash_page_dirty) > 0);
+			ret = __memp_bhwrite(dbmp, hp, bh_mfp, bhp, 0);
+			DB_ASSERT(env, atomic_read(&bhp->ref) > 0);
+#ifdef HAVE_STATISTICS
+			if (ret == 0)
+				++c_mp->stat.st_rw_evict;
+#endif
+		}
+#ifdef HAVE_STATISTICS
+		else
+			++c_mp->stat.st_ro_evict;
+#endif
+
+		/*
+		 * Freeze this buffer, if necessary.  That is, if the buffer
+		 * could be read by the oldest reader in the system.
+		 */
+		need_freeze = (SH_CHAIN_HASPREV(bhp, vc) ||
+		    (SH_CHAIN_HASNEXT(bhp, vc) && !obsolete));
+		if (ret == 0 && need_freeze) {
+			if (!aggressive ||
+			    F_ISSET(bhp, BH_DIRTY | BH_FROZEN))
+				goto next_hb;
+			if ((ret = __memp_bh_freeze(dbmp,
+			    infop, hp, bhp, &alloc_freeze)) == 0)
+				need_freeze = 0;
+			else if (ret == EBUSY || ret == EIO ||
+			    ret == ENOMEM || ret == ENOSPC)
+				ret = 0;
+			else {
+				DB_ASSERT(env, BH_REFCOUNT(bhp) > 0);
+				atomic_dec(env, &bhp->ref);
+				DB_ASSERT(env, b_lock);
+				F_CLR(bhp, BH_EXCLUSIVE);
+				MUTEX_UNLOCK(env, bhp->mtx_buf);
+				DB_ASSERT(env, !h_locked);
+				return (ret);
+			}
+		}
+
+		/*
+		 * If a write fails for any reason, we can't proceed.
+		 *
+		 * Also, we released the hash bucket lock while doing I/O, so
+		 * another thread may have acquired this buffer and incremented
+		 * the ref count or dirtied the buffer after we wrote it, in
+		 * which case we can't have it.
+		 *
+		 * If there's a write error and we're having problems finding
+		 * something to allocate, avoid selecting this buffer again
+		 * by raising its priority.
+		 */
+		MUTEX_LOCK(env, hp->mtx_hash);
+		h_locked = 1;
+		if (ret != 0 && (aggressive || bhp->priority < c_mp->lru_count))
+			bhp->priority = c_mp->lru_count +
+			     c_mp->stat.st_pages / MPOOL_PRI_DIRTY;
+
+		if (ret != 0 || BH_REFCOUNT(bhp) != 1 ||
+		    F_ISSET(bhp, BH_DIRTY) || need_freeze)
+			goto next_hb;
+
+		/*
+		 * If the buffer is frozen, thaw it and look for another one
+		 * we can use. (Calling __memp_bh_freeze above will not
+		 * mark bhp BH_FROZEN.)
+		 */
+		if (F_ISSET(bhp, BH_FROZEN)) {
+			DB_ASSERT(env, obsolete || SH_CHAIN_SINGLETON(bhp, vc));
+			DB_ASSERT(env, BH_REFCOUNT(bhp) > 0);
+			if (!F_ISSET(bhp, BH_THAWED)) {
+				/*
+				 * This call releases the hash bucket mutex.
+				 * We're going to retry the search, so we need
+				 * to re-lock it.
+				 */
+				if ((ret = __memp_bh_thaw(dbmp,
+				    infop, hp, bhp, NULL)) != 0)
+					return (ret);
+				MUTEX_READLOCK(env, hp->mtx_hash);
+			} else {
+				need_free = (atomic_dec(env, &bhp->ref) == 0);
+				F_CLR(bhp, BH_EXCLUSIVE);
+				MUTEX_UNLOCK(env, bhp->mtx_buf);
+				if (need_free) {
+					MPOOL_REGION_LOCK(env, infop);
+					SH_TAILQ_INSERT_TAIL(&c_mp->free_frozen,
+					    bhp, hq);
+					MPOOL_REGION_UNLOCK(env, infop);
+				}
+			}
+			bhp = NULL;
+			b_lock = alloc_freeze = 0;
+			goto retry_search;
+		}
+
+		/*
+		 * If we need some empty buffer headers for freezing, turn the
+		 * buffer we've found into frozen headers and put them on the
+		 * free list.  Only reset alloc_freeze if we've actually
+		 * allocated some frozen buffer headers.
+		 */
+		if (alloc_freeze) {
+			if ((ret = __memp_bhfree(dbmp,
+			     infop, bh_mfp, hp, bhp, 0)) != 0)
+				return (ret);
+			b_lock = 0;
+			h_locked = 0;
+
+			MVCC_MPROTECT(bhp->buf, bh_mfp->stat.st_pagesize,
+			    PROT_READ | PROT_WRITE | PROT_EXEC);
+
+			MPOOL_REGION_LOCK(env, infop);
+			SH_TAILQ_INSERT_TAIL(&c_mp->alloc_frozen,
+			    (BH_FROZEN_ALLOC *)bhp, links);
+			frozen_bhp = (BH_FROZEN_PAGE *)
+			    ((BH_FROZEN_ALLOC *)bhp + 1);
+			endp = (u_int8_t *)bhp->buf + bh_mfp->stat.st_pagesize;
+			while ((u_int8_t *)(frozen_bhp + 1) < endp) {
+				frozen_bhp->header.mtx_buf = MUTEX_INVALID;
+				SH_TAILQ_INSERT_TAIL(&c_mp->free_frozen,
+				    (BH *)frozen_bhp, hq);
+				frozen_bhp++;
+			}
+			MPOOL_REGION_UNLOCK(env, infop);
+
+			alloc_freeze = 0;
+			MUTEX_READLOCK(env, hp->mtx_hash);
+			h_locked = 1;
+			goto retry_search;
+		}
+
+		/*
+		 * Check to see if the buffer is the size we're looking for.
+		 * If so, we can simply reuse it.  Otherwise, free the buffer
+		 * and its space and keep looking.
+		 */
+		if (mfp != NULL &&
+		    mfp->stat.st_pagesize == bh_mfp->stat.st_pagesize) {
+			if ((ret = __memp_bhfree(dbmp,
+			     infop, bh_mfp, hp, bhp, 0)) != 0)
+				return (ret);
+			p = bhp;
+			goto found;
+		}
+
+		freed_space += sizeof(*bhp) + bh_mfp->stat.st_pagesize;
+		if ((ret =
+		    __memp_bhfree(dbmp, infop,
+			 bh_mfp, hp, bhp, BH_FREE_FREEMEM)) != 0)
+			return (ret);
+
+		/* Reset "aggressive" if we free any space. */
+		if (aggressive > 1)
+			aggressive = 1;
+
+		/*
+		 * Unlock this buffer and re-acquire the region lock. If
+		 * we're reaching here as a result of calling memp_bhfree, the
+		 * buffer lock has already been discarded.
+		 */
+		if (0) {
+next_hb:		if (bhp != NULL) {
+				DB_ASSERT(env, BH_REFCOUNT(bhp) > 0);
+				atomic_dec(env, &bhp->ref);
+				if (b_lock) {
+					F_CLR(bhp, BH_EXCLUSIVE);
+					MUTEX_UNLOCK(env, bhp->mtx_buf);
+				}
+			}
+			if (h_locked)
+				MUTEX_UNLOCK(env, hp->mtx_hash);
+			h_locked = 0;
+		}
+		MPOOL_REGION_LOCK(env, infop);
+
+		/*
+		 * Retry the allocation as soon as we've freed up sufficient
+		 * space.  We're likely to have to coalesce of memory to
+		 * satisfy the request, don't try until it's likely (possible?)
+		 * we'll succeed.
+		 */
+		if (freed_space >= 3 * len)
+			goto alloc;
+	}
+	/* NOTREACHED */
+}
+
+/*
+ * __memp_free --
+ *	Free some space from a cache region.
+ *
+ * PUBLIC: void __memp_free __P((REGINFO *, void *));
+ */
+void
+__memp_free(infop, buf)
+	REGINFO *infop;
+	void *buf;
+{
+	__env_alloc_free(infop, buf);
+}
diff --git a/mp/mp_bh.c b/mp/mp_bh.c
new file mode 100644
index 0000000..bedb430
--- /dev/null
+++ b/mp/mp_bh.c
@@ -0,0 +1,639 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/db_page.h"		/* Required for diagnostic code. */
+#include "dbinc/mp.h"
+#include "dbinc/log.h"
+#include "dbinc/txn.h"
+
+static int __memp_pgwrite
+	       __P((ENV *, DB_MPOOLFILE *, DB_MPOOL_HASH *, BH *));
+
+/*
+ * __memp_bhwrite --
+ *	Write the page associated with a given buffer header.
+ *
+ * PUBLIC: int __memp_bhwrite __P((DB_MPOOL *,
+ * PUBLIC:      DB_MPOOL_HASH *, MPOOLFILE *, BH *, int));
+ */
+int
+__memp_bhwrite(dbmp, hp, mfp, bhp, open_extents)
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOLFILE *mfp;
+	BH *bhp;
+	int open_extents;
+{
+	DB_MPOOLFILE *dbmfp;
+	DB_MPREG *mpreg;
+	ENV *env;
+	int ret;
+
+	env = dbmp->env;
+
+	/*
+	 * If the file has been removed or is a closed temporary file, we're
+	 * done -- the page-write function knows how to handle the fact that
+	 * we don't have (or need!) any real file descriptor information.
+	 */
+	if (mfp->deadfile)
+		return (__memp_pgwrite(env, NULL, hp, bhp));
+
+	/*
+	 * Walk the process' DB_MPOOLFILE list and find a file descriptor for
+	 * the file.  We also check that the descriptor is open for writing.
+	 */
+	MUTEX_LOCK(env, dbmp->mutex);
+	TAILQ_FOREACH(dbmfp, &dbmp->dbmfq, q)
+		if (dbmfp->mfp == mfp && !F_ISSET(dbmfp, MP_READONLY)) {
+			++dbmfp->ref;
+			break;
+		}
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	if (dbmfp != NULL) {
+		/*
+		 * Temporary files may not have been created.  We only handle
+		 * temporary files in this path, because only the process that
+		 * created a temporary file will ever flush buffers to it.
+		 */
+		if (dbmfp->fhp == NULL) {
+			/* We may not be allowed to create backing files. */
+			if (mfp->no_backing_file) {
+				--dbmfp->ref;
+				return (EPERM);
+			}
+
+			MUTEX_LOCK(env, dbmp->mutex);
+			if (dbmfp->fhp == NULL) {
+				ret = __db_tmp_open(env,
+				    F_ISSET(env->dbenv, DB_ENV_DIRECT_DB) ?
+				    DB_OSO_DIRECT : 0, &dbmfp->fhp);
+			} else
+				ret = 0;
+			MUTEX_UNLOCK(env, dbmp->mutex);
+			if (ret != 0) {
+				__db_errx(env,
+				    "unable to create temporary backing file");
+				--dbmfp->ref;
+				return (ret);
+			}
+		}
+
+		goto pgwrite;
+	}
+
+	/*
+	 * There's no file handle for this file in our process.
+	 *
+	 * !!!
+	 * It's the caller's choice if we're going to open extent files.
+	 */
+	if (!open_extents && F_ISSET(mfp, MP_EXTENT))
+		return (EPERM);
+
+	/*
+	 * !!!
+	 * Don't try to attach to temporary files.  There are two problems in
+	 * trying to do that.  First, if we have different privileges than the
+	 * process that "owns" the temporary file, we might create the backing
+	 * disk file such that the owning process couldn't read/write its own
+	 * buffers, e.g., memp_trickle running as root creating a file owned
+	 * as root, mode 600.  Second, if the temporary file has already been
+	 * created, we don't have any way of finding out what its real name is,
+	 * and, even if we did, it was already unlinked (so that it won't be
+	 * left if the process dies horribly).  This decision causes a problem,
+	 * however: if the temporary file consumes the entire buffer cache,
+	 * and the owner doesn't flush the buffers to disk, we could end up
+	 * with resource starvation, and the memp_trickle thread couldn't do
+	 * anything about it.  That's a pretty unlikely scenario, though.
+	 *
+	 * Note we should never get here when the temporary file in question
+	 * has already been closed in another process, in which case it should
+	 * be marked dead.
+	 */
+	if (F_ISSET(mfp, MP_TEMP) || mfp->no_backing_file)
+		return (EPERM);
+
+	/*
+	 * It's not a page from a file we've opened.  If the file requires
+	 * application-specific input/output processing, see if this process
+	 * has ever registered information as to how to write this type of
+	 * file.  If not, there's nothing we can do.
+	 */
+	if (mfp->ftype != 0 && mfp->ftype != DB_FTYPE_SET) {
+		MUTEX_LOCK(env, dbmp->mutex);
+		LIST_FOREACH(mpreg, &dbmp->dbregq, q)
+			if (mpreg->ftype == mfp->ftype)
+				break;
+		MUTEX_UNLOCK(env, dbmp->mutex);
+		if (mpreg == NULL)
+			return (EPERM);
+	}
+
+	/*
+	 * Try and open the file, specifying the known underlying shared area.
+	 *
+	 * !!!
+	 * There's no negative cache, so we may repeatedly try and open files
+	 * that we have previously tried (and failed) to open.
+	 */
+	if ((ret = __memp_fcreate(env, &dbmfp)) != 0)
+		return (ret);
+	if ((ret = __memp_fopen(dbmfp, mfp,
+	    NULL, NULL, DB_DURABLE_UNKNOWN, 0, mfp->stat.st_pagesize)) != 0) {
+		(void)__memp_fclose(dbmfp, 0);
+
+		/*
+		 * Ignore any error if the file is marked dead, assume the file
+		 * was removed from under us.
+		 */
+		if (!mfp->deadfile)
+			return (ret);
+
+		dbmfp = NULL;
+	}
+
+pgwrite:
+	MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize,
+	    PROT_READ | PROT_WRITE | PROT_EXEC);
+	ret = __memp_pgwrite(env, dbmfp, hp, bhp);
+	if (dbmfp == NULL)
+		return (ret);
+
+	/*
+	 * Discard our reference, and, if we're the last reference, make sure
+	 * the file eventually gets closed.
+	 */
+	MUTEX_LOCK(env, dbmp->mutex);
+	if (dbmfp->ref == 1)
+		F_SET(dbmfp, MP_FLUSH);
+	else
+		--dbmfp->ref;
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	return (ret);
+}
+
+/*
+ * __memp_pgread --
+ *	Read a page from a file.
+ *
+ * PUBLIC: int __memp_pgread __P((DB_MPOOLFILE *, BH *, int));
+ */
+int
+__memp_pgread(dbmfp, bhp, can_create)
+	DB_MPOOLFILE *dbmfp;
+	BH *bhp;
+	int can_create;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+	size_t len, nr;
+	u_int32_t pagesize;
+	int ret;
+
+	env = dbmfp->env;
+	mfp = dbmfp->mfp;
+	pagesize = mfp->stat.st_pagesize;
+
+	/* We should never be called with a dirty or unlocked buffer. */
+	DB_ASSERT(env, !F_ISSET(bhp, BH_DIRTY_CREATE | BH_FROZEN));
+	DB_ASSERT(env, can_create || !F_ISSET(bhp, BH_DIRTY));
+	DB_ASSERT(env, F_ISSET(bhp, BH_EXCLUSIVE));
+
+	/* Mark the buffer as in transistion. */
+	F_SET(bhp, BH_TRASH);
+
+	/*
+	 * Temporary files may not yet have been created.  We don't create
+	 * them now, we create them when the pages have to be flushed.
+	 */
+	nr = 0;
+	if (dbmfp->fhp != NULL)
+		if ((ret = __os_io(env, DB_IO_READ, dbmfp->fhp,
+		    bhp->pgno, pagesize, 0, pagesize, bhp->buf, &nr)) != 0)
+			goto err;
+
+	/*
+	 * The page may not exist; if it doesn't, nr may well be 0, but we
+	 * expect the underlying OS calls not to return an error code in
+	 * this case.
+	 */
+	if (nr < pagesize) {
+		/*
+		 * Don't output error messages for short reads.  In particular,
+		 * DB recovery processing may request pages never written to
+		 * disk or for which only some part have been written to disk,
+		 * in which case we won't find the page.  The caller must know
+		 * how to handle the error.
+		 */
+		if (!can_create) {
+			ret = DB_PAGE_NOTFOUND;
+			goto err;
+		}
+
+		/* Clear any bytes that need to be cleared. */
+		len = mfp->clear_len == DB_CLEARLEN_NOTSET ?
+		    pagesize : mfp->clear_len;
+		memset(bhp->buf, 0, len);
+
+#if defined(DIAGNOSTIC) || defined(UMRW)
+		/*
+		 * If we're running in diagnostic mode, corrupt any bytes on
+		 * the page that are unknown quantities for the caller.
+		 */
+		if (len < pagesize)
+			memset(bhp->buf + len, CLEAR_BYTE, pagesize - len);
+#endif
+#ifdef HAVE_STATISTICS
+		++mfp->stat.st_page_create;
+	} else
+		++mfp->stat.st_page_in;
+#else
+	}
+#endif
+
+	/* Call any pgin function. */
+	ret = mfp->ftype == 0 ? 0 : __memp_pg(dbmfp, bhp->pgno, bhp->buf, 1);
+
+	/*
+	 * If no errors occurred, the data is now valid, clear the BH_TRASH
+	 * flag.
+	 */
+	if (ret == 0)
+		F_CLR(bhp, BH_TRASH);
+err:	return (ret);
+}
+
+/*
+ * __memp_pgwrite --
+ *	Write a page to a file.
+ */
+static int
+__memp_pgwrite(env, dbmfp, hp, bhp)
+	ENV *env;
+	DB_MPOOLFILE *dbmfp;
+	DB_MPOOL_HASH *hp;
+	BH *bhp;
+{
+	DB_LSN lsn;
+	MPOOLFILE *mfp;
+	size_t nw;
+	int ret;
+	void * buf;
+
+	/*
+	 * Since writing does not require exclusive access, another thread
+	 * could have already written this buffer.
+	 */
+	if (!F_ISSET(bhp, BH_DIRTY))
+		return (0);
+
+	mfp = dbmfp == NULL ? NULL : dbmfp->mfp;
+	ret = 0;
+	buf = NULL;
+
+	/* We should never be called with a frozen or trashed buffer. */
+	DB_ASSERT(env, !F_ISSET(bhp, BH_FROZEN | BH_TRASH));
+
+	/*
+	 * It's possible that the underlying file doesn't exist, either
+	 * because of an outright removal or because it was a temporary
+	 * file that's been closed.
+	 *
+	 * !!!
+	 * Once we pass this point, we know that dbmfp and mfp aren't NULL,
+	 * and that we have a valid file reference.
+	 */
+	if (mfp == NULL || mfp->deadfile)
+		goto file_dead;
+
+	/*
+	 * If the page is in a file for which we have LSN information, we have
+	 * to ensure the appropriate log records are on disk.
+	 */
+	if (LOGGING_ON(env) && mfp->lsn_off != DB_LSN_OFF_NOTSET &&
+	    !IS_CLIENT_PGRECOVER(env)) {
+		memcpy(&lsn, bhp->buf + mfp->lsn_off, sizeof(DB_LSN));
+		if (!IS_NOT_LOGGED_LSN(lsn) &&
+		    (ret = __log_flush(env, &lsn)) != 0)
+			goto err;
+	}
+
+#ifdef DIAGNOSTIC
+	/*
+	 * Verify write-ahead logging semantics.
+	 *
+	 * !!!
+	 * Two special cases.  There is a single field on the meta-data page,
+	 * the last-page-number-in-the-file field, for which we do not log
+	 * changes.  If the page was originally created in a database that
+	 * didn't have logging turned on, we can see a page marked dirty but
+	 * for which no corresponding log record has been written.  However,
+	 * the only way that a page can be created for which there isn't a
+	 * previous log record and valid LSN is when the page was created
+	 * without logging turned on, and so we check for that special-case
+	 * LSN value.
+	 *
+	 * Second, when a client is reading database pages from a master
+	 * during an internal backup, we may get pages modified after
+	 * the current end-of-log.
+	 */
+	if (LOGGING_ON(env) && !IS_NOT_LOGGED_LSN(LSN(bhp->buf)) &&
+	    !IS_CLIENT_PGRECOVER(env)) {
+		/*
+		 * There is a potential race here.  If we are in the midst of
+		 * switching log files, it's possible we could test against the
+		 * old file and the new offset in the log region's LSN.  If we
+		 * fail the first test, acquire the log mutex and check again.
+		 */
+		DB_LOG *dblp;
+		LOG *lp;
+
+		dblp = env->lg_handle;
+		lp = dblp->reginfo.primary;
+		if (!lp->db_log_inmemory &&
+		    LOG_COMPARE(&lp->s_lsn, &LSN(bhp->buf)) <= 0) {
+			MUTEX_LOCK(env, lp->mtx_flush);
+			DB_ASSERT(env,
+			    LOG_COMPARE(&lp->s_lsn, &LSN(bhp->buf)) > 0);
+			MUTEX_UNLOCK(env, lp->mtx_flush);
+		}
+	}
+#endif
+
+	/*
+	 * Call any pgout function.  If we have the page exclusive then
+	 * we are going to reuse it otherwise make a copy of the page so
+	 * that others can continue looking at the page while we write it.
+	 */
+	buf = bhp->buf;
+	if (mfp->ftype != 0) {
+		if (F_ISSET(bhp, BH_EXCLUSIVE))
+			F_SET(bhp, BH_TRASH);
+		else {
+			if ((ret =
+			    __os_malloc(env, mfp->stat.st_pagesize, &buf)) != 0)
+				goto err;
+			memcpy(buf, bhp->buf, mfp->stat.st_pagesize);
+		}
+		if ((ret = __memp_pg(dbmfp, bhp->pgno, buf, 0)) != 0)
+			goto err;
+	}
+
+	/* Write the page. */
+	if ((ret = __os_io(
+	    env, DB_IO_WRITE, dbmfp->fhp, bhp->pgno, mfp->stat.st_pagesize,
+	    0, mfp->stat.st_pagesize, buf, &nw)) != 0) {
+		__db_errx(env, "%s: write failed for page %lu",
+		    __memp_fn(dbmfp), (u_long)bhp->pgno);
+		goto err;
+	}
+	STAT(++mfp->stat.st_page_out);
+	if (bhp->pgno > mfp->last_flushed_pgno) {
+		MUTEX_LOCK(env, mfp->mutex);
+		if (bhp->pgno > mfp->last_flushed_pgno)
+			mfp->last_flushed_pgno = bhp->pgno;
+		MUTEX_UNLOCK(env, mfp->mutex);
+	}
+
+err:
+file_dead:
+	if (buf != NULL && buf != bhp->buf)
+		__os_free(env, buf);
+	/*
+	 * !!!
+	 * Once we pass this point, dbmfp and mfp may be NULL, we may not have
+	 * a valid file reference.
+	 */
+
+	/*
+	 * Update the hash bucket statistics, reset the flags.  If we were
+	 * successful, the page is no longer dirty.  Someone else may have
+	 * also written the page so we need to latch the hash bucket here
+	 * to get the accounting correct.  Since we have the buffer
+	 * shared it cannot be marked dirty again till we release it.
+	 * This is the only place we update the flags field only holding
+	 * a shared latch.
+	 */
+	if (F_ISSET(bhp, BH_DIRTY | BH_TRASH)) {
+		MUTEX_LOCK(env, hp->mtx_hash);
+		DB_ASSERT(env, !SH_CHAIN_HASNEXT(bhp, vc));
+		if (ret == 0 && F_ISSET(bhp, BH_DIRTY)) {
+			F_CLR(bhp, BH_DIRTY | BH_DIRTY_CREATE);
+			DB_ASSERT(env, atomic_read(&hp->hash_page_dirty) > 0);
+			atomic_dec(env, &hp->hash_page_dirty);
+		}
+
+		/* put the page back if necessary. */
+		if ((ret != 0 || BH_REFCOUNT(bhp) > 1) &&
+		    F_ISSET(bhp, BH_TRASH)) {
+			ret = __memp_pg(dbmfp, bhp->pgno, bhp->buf, 1);
+			F_CLR(bhp, BH_TRASH);
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+
+	return (ret);
+}
+
+/*
+ * __memp_pg --
+ *	Call the pgin/pgout routine.
+ *
+ * PUBLIC: int __memp_pg __P((DB_MPOOLFILE *, db_pgno_t, void *, int));
+ */
+int
+__memp_pg(dbmfp, pgno, buf, is_pgin)
+	DB_MPOOLFILE *dbmfp;
+	db_pgno_t pgno;
+	void *buf;
+	int is_pgin;
+{
+	DBT dbt, *dbtp;
+	DB_MPOOL *dbmp;
+	DB_MPREG *mpreg;
+	ENV *env;
+	MPOOLFILE *mfp;
+	int ftype, ret;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+
+	if ((ftype = mfp->ftype) == DB_FTYPE_SET)
+		mpreg = dbmp->pg_inout;
+	else {
+		MUTEX_LOCK(env, dbmp->mutex);
+		LIST_FOREACH(mpreg, &dbmp->dbregq, q)
+			if (ftype == mpreg->ftype)
+				break;
+		MUTEX_UNLOCK(env, dbmp->mutex);
+	}
+	if (mpreg == NULL)
+		return (0);
+
+	if (mfp->pgcookie_len == 0)
+		dbtp = NULL;
+	else {
+		DB_SET_DBT(dbt, R_ADDR(
+		    dbmp->reginfo, mfp->pgcookie_off), mfp->pgcookie_len);
+		dbtp = &dbt;
+	}
+
+	if (is_pgin) {
+		if (mpreg->pgin != NULL && (ret =
+		    mpreg->pgin(env->dbenv, pgno, buf, dbtp)) != 0)
+			goto err;
+	} else
+		if (mpreg->pgout != NULL && (ret =
+		    mpreg->pgout(env->dbenv, pgno, buf, dbtp)) != 0)
+			goto err;
+
+	return (0);
+
+err:	__db_errx(env, "%s: %s failed for page %lu",
+	    __memp_fn(dbmfp), is_pgin ? "pgin" : "pgout", (u_long)pgno);
+	return (ret);
+}
+
+/*
+ * __memp_bhfree --
+ *	Free a bucket header and its referenced data.
+ *
+ * PUBLIC: int __memp_bhfree __P((DB_MPOOL *,
+ * PUBLIC:	REGINFO *, MPOOLFILE *, DB_MPOOL_HASH *, BH *, u_int32_t));
+ */
+int
+__memp_bhfree(dbmp, infop, mfp, hp, bhp, flags)
+	DB_MPOOL *dbmp;
+	REGINFO *infop;
+	MPOOLFILE *mfp;
+	DB_MPOOL_HASH *hp;
+	BH *bhp;
+	u_int32_t flags;
+{
+	ENV *env;
+#ifdef DIAGNOSTIC
+	DB_LSN vlsn;
+#endif
+	BH *prev_bhp;
+	MPOOL *c_mp;
+	int ret, t_ret;
+#ifdef DIAG_MVCC
+	size_t pagesize;
+#endif
+
+	ret = 0;
+
+	/*
+	 * Assumes the hash bucket is locked and the MPOOL is not.
+	 */
+	env = dbmp->env;
+#ifdef DIAG_MVCC
+	if (mfp != NULL)
+		pagesize = mfp->stat.st_pagesize;
+#endif
+
+	DB_ASSERT(env, LF_ISSET(BH_FREE_UNLOCKED) ||
+	    (hp != NULL && MUTEX_IS_OWNED(env, hp->mtx_hash)));
+	DB_ASSERT(env, BH_REFCOUNT(bhp) == 1 &&
+	    !F_ISSET(bhp, BH_DIRTY | BH_FROZEN));
+	DB_ASSERT(env, LF_ISSET(BH_FREE_UNLOCKED) ||
+	    SH_CHAIN_SINGLETON(bhp, vc) || (SH_CHAIN_HASNEXT(bhp, vc) &&
+	    (SH_CHAIN_NEXTP(bhp, vc, __bh)->td_off == bhp->td_off ||
+	    bhp->td_off == INVALID_ROFF ||
+	    IS_MAX_LSN(*VISIBLE_LSN(env, bhp)) ||
+	    BH_OBSOLETE(bhp, hp->old_reader, vlsn))));
+
+	/*
+	 * Delete the buffer header from the hash bucket queue or the
+	 * version chain.
+	 */
+	if (hp == NULL)
+		goto no_hp;
+	prev_bhp = SH_CHAIN_PREV(bhp, vc, __bh);
+	if (!SH_CHAIN_HASNEXT(bhp, vc)) {
+		if (prev_bhp != NULL)
+			SH_TAILQ_INSERT_AFTER(&hp->hash_bucket,
+			    bhp, prev_bhp, hq, __bh);
+		SH_TAILQ_REMOVE(&hp->hash_bucket, bhp, hq, __bh);
+	}
+	SH_CHAIN_REMOVE(bhp, vc, __bh);
+
+	/*
+	 * Remove the reference to this buffer from the transaction that
+	 * created it, if any.  When the BH_FREE_UNLOCKED flag is set, we're
+	 * discarding the environment, so the transaction region is already
+	 * gone.
+	 */
+	if (bhp->td_off != INVALID_ROFF && !LF_ISSET(BH_FREE_UNLOCKED)) {
+		ret = __txn_remove_buffer(
+		    env, BH_OWNER(env, bhp), hp->mtx_hash);
+		bhp->td_off = INVALID_ROFF;
+	}
+
+	/*
+	 * We're going to use the memory for something else -- it had better be
+	 * accessible.
+	 */
+no_hp:	MVCC_MPROTECT(bhp->buf, pagesize, PROT_READ | PROT_WRITE | PROT_EXEC);
+
+	/*
+	 * Discard the hash bucket's mutex, it's no longer needed, and
+	 * we don't want to be holding it when acquiring other locks.
+	 */
+	if (!LF_ISSET(BH_FREE_UNLOCKED))
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+
+	/*
+	 * If we're only removing this header from the chain for reuse, we're
+	 * done.
+	 */
+	if (LF_ISSET(BH_FREE_REUSE))
+		return (ret);
+
+	/*
+	 * If we're not reusing the buffer immediately, free the buffer for
+	 * real.
+	 */
+	if (!LF_ISSET(BH_FREE_UNLOCKED))
+		MUTEX_UNLOCK(env, bhp->mtx_buf);
+	if (LF_ISSET(BH_FREE_FREEMEM)) {
+		if ((ret = __mutex_free(env, &bhp->mtx_buf)) != 0)
+			return (ret);
+		MPOOL_REGION_LOCK(env, infop);
+
+		MVCC_BHUNALIGN(bhp);
+		__memp_free(infop, bhp);
+		c_mp = infop->primary;
+		c_mp->stat.st_pages--;
+
+		MPOOL_REGION_UNLOCK(env, infop);
+	}
+
+	if (mfp == NULL)
+		return (ret);
+
+	/*
+	 * Decrement the reference count of the underlying MPOOLFILE.
+	 * If this is its last reference, remove it.
+	 */
+	MUTEX_LOCK(env, mfp->mutex);
+	if (--mfp->block_cnt == 0 && mfp->mpf_cnt == 0) {
+		if ((t_ret = __memp_mf_discard(dbmp, mfp)) != 0 && ret == 0)
+			ret = t_ret;
+	} else
+		MUTEX_UNLOCK(env, mfp->mutex);
+
+	return (ret);
+}
diff --git a/mp/mp_fget.c b/mp/mp_fget.c
new file mode 100644
index 0000000..5fdee5a
--- /dev/null
+++ b/mp/mp_fget.c
@@ -0,0 +1,1161 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+/*
+ * __memp_fget_pp --
+ *	DB_MPOOLFILE->get pre/post processing.
+ *
+ * PUBLIC: int __memp_fget_pp
+ * PUBLIC:     __P((DB_MPOOLFILE *, db_pgno_t *, DB_TXN *, u_int32_t, void *));
+ */
+int
+__memp_fget_pp(dbmfp, pgnoaddr, txnp, flags, addrp)
+	DB_MPOOLFILE *dbmfp;
+	db_pgno_t *pgnoaddr;
+	DB_TXN *txnp;
+	u_int32_t flags;
+	void *addrp;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int rep_blocked, ret;
+
+	env = dbmfp->env;
+
+	MPF_ILLEGAL_BEFORE_OPEN(dbmfp, "DB_MPOOLFILE->get");
+
+	/*
+	 * Validate arguments.
+	 *
+	 * !!!
+	 * Don't test for DB_MPOOL_CREATE and DB_MPOOL_NEW flags for readonly
+	 * files here, and create non-existent pages in readonly files if the
+	 * flags are set, later.  The reason is that the hash access method
+	 * wants to get empty pages that don't really exist in readonly files.
+	 * The only alternative is for hash to write the last "bucket" all the
+	 * time, which we don't want to do because one of our big goals in life
+	 * is to keep database files small.  It's sleazy as hell, but we catch
+	 * any attempt to actually write the file in memp_fput().
+	 */
+#define	OKFLAGS		(DB_MPOOL_CREATE | DB_MPOOL_DIRTY | \
+	    DB_MPOOL_EDIT | DB_MPOOL_LAST | DB_MPOOL_NEW)
+	if (flags != 0) {
+		if ((ret = __db_fchk(env, "memp_fget", flags, OKFLAGS)) != 0)
+			return (ret);
+
+		switch (flags) {
+		case DB_MPOOL_DIRTY:
+		case DB_MPOOL_CREATE:
+		case DB_MPOOL_EDIT:
+		case DB_MPOOL_LAST:
+		case DB_MPOOL_NEW:
+			break;
+		default:
+			return (__db_ferr(env, "memp_fget", 1));
+		}
+	}
+
+	ENV_ENTER(env, ip);
+
+	rep_blocked = 0;
+	if (txnp == NULL && IS_ENV_REPLICATED(env)) {
+		if ((ret = __op_rep_enter(env)) != 0)
+			goto err;
+		rep_blocked = 1;
+	}
+	ret = __memp_fget(dbmfp, pgnoaddr, ip, txnp, flags, addrp);
+	/*
+	 * We only decrement the count in op_rep_exit if the operation fails.
+	 * Otherwise the count will be decremented when the page is no longer
+	 * pinned in memp_fput.
+	 */
+	if (ret != 0 && rep_blocked)
+		(void)__op_rep_exit(env);
+
+	/* Similarly if an app has a page pinned it is ACTIVE. */
+err:	if (ret != 0)
+		ENV_LEAVE(env, ip);
+
+	return (ret);
+}
+
+/*
+ * __memp_fget --
+ *	Get a page from the file.
+ *
+ * PUBLIC: int __memp_fget __P((DB_MPOOLFILE *,
+ * PUBLIC:     db_pgno_t *, DB_THREAD_INFO *, DB_TXN *, u_int32_t, void *));
+ */
+int
+__memp_fget(dbmfp, pgnoaddr, ip, txn, flags, addrp)
+	DB_MPOOLFILE *dbmfp;
+	db_pgno_t *pgnoaddr;
+	DB_THREAD_INFO *ip;
+	DB_TXN *txn;
+	u_int32_t flags;
+	void *addrp;
+{
+	enum { FIRST_FOUND, FIRST_MISS, SECOND_FOUND, SECOND_MISS } state;
+	BH *alloc_bhp, *bhp, *oldest_bhp;
+	ENV *env;
+	DB_LSN *read_lsnp, vlsn;
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *c_mp;
+	MPOOLFILE *mfp;
+	PIN_LIST *list, *lp;
+	REGENV *renv;
+	REGINFO *infop, *t_infop, *reginfo;
+	TXN_DETAIL *td;
+	roff_t list_off, mf_offset;
+	u_int32_t bucket, pinmax, st_hsearch;
+	int b_incr, b_lock, h_locked, dirty, extending;
+	int makecopy, mvcc, need_free, ret;
+
+	*(void **)addrp = NULL;
+	COMPQUIET(c_mp, NULL);
+	COMPQUIET(infop, NULL);
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+
+	mfp = dbmfp->mfp;
+	mvcc = mfp->multiversion && (txn != NULL);
+	mf_offset = R_OFFSET(dbmp->reginfo, mfp);
+	alloc_bhp = bhp = oldest_bhp = NULL;
+	read_lsnp = NULL;
+	td = NULL;
+	hp = NULL;
+	b_incr = b_lock = h_locked = extending = makecopy = ret = 0;
+
+	if (LF_ISSET(DB_MPOOL_DIRTY)) {
+		if (F_ISSET(dbmfp, MP_READONLY)) {
+			__db_errx(env,
+			    "%s: dirty flag set for readonly file page",
+			    __memp_fn(dbmfp));
+			return (EINVAL);
+		}
+		if ((ret = __db_fcchk(env, "DB_MPOOLFILE->get",
+		    flags, DB_MPOOL_DIRTY, DB_MPOOL_EDIT)) != 0)
+			return (ret);
+	}
+
+	dirty = LF_ISSET(DB_MPOOL_DIRTY | DB_MPOOL_EDIT | DB_MPOOL_FREE);
+	LF_CLR(DB_MPOOL_DIRTY | DB_MPOOL_EDIT);
+
+	/*
+	 * If the transaction is being used to update a multiversion database
+	 * for the first time, set the read LSN.  In addition, if this is an
+	 * update, allocate a mutex.  If no transaction has been supplied, that
+	 * will be caught later, when we know whether one is required.
+	 */
+	if (mvcc && txn != NULL && txn->td != NULL) {
+		/* We're only interested in the ultimate parent transaction. */
+		while (txn->parent != NULL)
+			txn = txn->parent;
+		td = (TXN_DETAIL *)txn->td;
+		if (F_ISSET(txn, TXN_SNAPSHOT)) {
+			read_lsnp = &td->read_lsn;
+			if (IS_MAX_LSN(*read_lsnp) &&
+			    (ret = __log_current_lsn(env, read_lsnp,
+			    NULL, NULL)) != 0)
+				return (ret);
+		}
+		if ((dirty || LF_ISSET(DB_MPOOL_CREATE | DB_MPOOL_NEW)) &&
+		    td->mvcc_mtx == MUTEX_INVALID && (ret =
+		    __mutex_alloc(env, MTX_TXN_MVCC, 0, &td->mvcc_mtx)) != 0)
+			return (ret);
+	}
+
+	switch (flags) {
+	case DB_MPOOL_LAST:
+		/* Get the last page number in the file. */
+		MUTEX_LOCK(env, mfp->mutex);
+		*pgnoaddr = mfp->last_pgno;
+		MUTEX_UNLOCK(env, mfp->mutex);
+		break;
+	case DB_MPOOL_NEW:
+		/*
+		 * If always creating a page, skip the first search
+		 * of the hash bucket.
+		 */
+		goto newpg;
+	case DB_MPOOL_CREATE:
+	default:
+		break;
+	}
+
+	/*
+	 * If mmap'ing the file and the page is not past the end of the file,
+	 * just return a pointer.  We can't use R_ADDR here: this is an offset
+	 * into an mmap'd file, not a shared region, and doesn't change for
+	 * private environments.
+	 *
+	 * The page may be past the end of the file, so check the page number
+	 * argument against the original length of the file.  If we previously
+	 * returned pages past the original end of the file, last_pgno will
+	 * have been updated to match the "new" end of the file, and checking
+	 * against it would return pointers past the end of the mmap'd region.
+	 *
+	 * If another process has opened the file for writing since we mmap'd
+	 * it, we will start playing the game by their rules, i.e. everything
+	 * goes through the cache.  All pages previously returned will be safe,
+	 * as long as the correct locking protocol was observed.
+	 *
+	 * We don't discard the map because we don't know when all of the
+	 * pages will have been discarded from the process' address space.
+	 * It would be possible to do so by reference counting the open
+	 * pages from the mmap, but it's unclear to me that it's worth it.
+	 */
+	if (dbmfp->addr != NULL &&
+	    F_ISSET(mfp, MP_CAN_MMAP) && *pgnoaddr <= mfp->orig_last_pgno) {
+		*(void **)addrp = (u_int8_t *)dbmfp->addr +
+		    (*pgnoaddr * mfp->stat.st_pagesize);
+		STAT(++mfp->stat.st_map);
+		return (0);
+	}
+
+	/*
+	 * Determine the cache and hash bucket where this page lives and get
+	 * local pointers to them.  Reset on each pass through this code, the
+	 * page number can change.
+	 */
+	MP_GET_BUCKET(env, mfp, *pgnoaddr, &infop, hp, bucket, ret);
+	if (ret != 0)
+		return (ret);
+	c_mp = infop->primary;
+
+	if (0) {
+		/* if we search again, get an exclusive lock. */
+retry:		MUTEX_LOCK(env, hp->mtx_hash);
+	}
+
+	/* Search the hash chain for the page. */
+	st_hsearch = 0;
+	h_locked = 1;
+	SH_TAILQ_FOREACH(bhp, &hp->hash_bucket, hq, __bh) {
+		++st_hsearch;
+		if (bhp->pgno != *pgnoaddr || bhp->mf_offset != mf_offset)
+			continue;
+
+		/* Snapshot reads -- get the version visible at read_lsn. */
+		if (read_lsnp != NULL) {
+			while (bhp != NULL &&
+			    !BH_OWNED_BY(env, bhp, txn) &&
+			    !BH_VISIBLE(env, bhp, read_lsnp, vlsn))
+				bhp = SH_CHAIN_PREV(bhp, vc, __bh);
+	
+			/* 
+			 * We can get a null bhp if we are looking for a 
+			 * page that was created after the transaction was
+			 * started so its not visible  (i.e. page added to 
+			 * the BTREE in a subsequent txn).
+			 */
+			if (bhp == NULL) {
+				ret = DB_PAGE_NOTFOUND;
+				goto err;
+			}
+		}
+
+		makecopy = mvcc && dirty && !BH_OWNED_BY(env, bhp, txn);
+
+		/*
+		 * Increment the reference count.  This signals that the
+		 * buffer may not be discarded.  We must drop the hash
+		 * mutex before we lock the buffer mutex.
+		 */
+		if (BH_REFCOUNT(bhp) == UINT16_MAX) {
+			__db_errx(env,
+			    "%s: page %lu: reference count overflow",
+			    __memp_fn(dbmfp), (u_long)bhp->pgno);
+			ret = __env_panic(env, EINVAL);
+			goto err;
+		}
+		atomic_inc(env, &bhp->ref);
+		b_incr = 1;
+
+		/*
+		 * Lock the buffer. If the page is being read in or modified it
+		 * will be exclusively locked and we will block.
+		 */
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		h_locked = 0;
+		if (dirty || extending || makecopy || F_ISSET(bhp, BH_FROZEN)) {
+xlatch:			if (LF_ISSET(DB_MPOOL_TRY)) {
+				if ((ret =
+				    MUTEX_TRYLOCK(env, bhp->mtx_buf)) != 0)
+					goto err;
+			} else
+				MUTEX_LOCK(env, bhp->mtx_buf);
+			F_SET(bhp, BH_EXCLUSIVE);
+		} else if (LF_ISSET(DB_MPOOL_TRY)) {
+			if ((ret = MUTEX_TRY_READLOCK(env, bhp->mtx_buf)) != 0)
+				goto err;
+		} else
+			MUTEX_READLOCK(env, bhp->mtx_buf);
+
+#ifdef HAVE_SHARED_LATCHES
+		/*
+		 * If buffer is still in transit once we have a shared latch,
+		 * upgrade to an exclusive latch.
+		 */
+		if (F_ISSET(bhp, BH_FREED | BH_TRASH) &&
+		    !F_ISSET(bhp, BH_EXCLUSIVE)) {
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			goto xlatch;
+		}
+#else
+		F_SET(bhp, BH_EXCLUSIVE);
+#endif
+		b_lock = 1;
+
+		/*
+		 * If the buffer was frozen before we waited for any I/O to
+		 * complete and is still frozen, we will need to thaw it.
+		 * Otherwise, it was thawed while we waited, and we need to
+		 * search again.
+		 */
+		if (F_ISSET(bhp, BH_THAWED)) {
+thawed:			need_free = (atomic_dec(env, &bhp->ref) == 0);
+			b_incr = 0;
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			b_lock = 0;
+			if (need_free) {
+				MPOOL_REGION_LOCK(env, infop);
+				SH_TAILQ_INSERT_TAIL(&c_mp->free_frozen,
+				    bhp, hq);
+				MPOOL_REGION_UNLOCK(env, infop);
+			}
+			bhp = NULL;
+			goto retry;
+		}
+
+		/*
+		 * If the buffer we wanted was frozen or thawed while we
+		 * waited, we need to start again.  That is indicated by
+		 * a new buffer header in the version chain owned by the same
+		 * transaction as the one we pinned.
+		 *
+		 * Also, if we're doing an unversioned read on a multiversion
+		 * file, another thread may have dirtied this buffer while we
+		 * swapped from the hash bucket lock to the buffer lock.
+		 */
+		if (SH_CHAIN_HASNEXT(bhp, vc) &&
+		    (SH_CHAIN_NEXTP(bhp, vc, __bh)->td_off == bhp->td_off ||
+		    (!dirty && read_lsnp == NULL))) {
+			DB_ASSERT(env, b_incr && BH_REFCOUNT(bhp) != 0);
+			atomic_dec(env, &bhp->ref);
+			b_incr = 0;
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			b_lock = 0;
+			bhp = NULL;
+			goto retry;
+		} else if (dirty && SH_CHAIN_HASNEXT(bhp, vc)) {
+			ret = DB_LOCK_DEADLOCK;
+			goto err;
+		} else if (F_ISSET(bhp, BH_FREED) && flags != DB_MPOOL_CREATE &&
+		    flags != DB_MPOOL_NEW && flags != DB_MPOOL_FREE) {
+			ret = DB_PAGE_NOTFOUND;
+			goto err;
+		}
+
+		STAT(++mfp->stat.st_cache_hit);
+		break;
+	}
+
+#ifdef HAVE_STATISTICS
+	/*
+	 * Update the hash bucket search statistics -- do now because our next
+	 * search may be for a different bucket.
+	 */
+	++c_mp->stat.st_hash_searches;
+	if (st_hsearch > c_mp->stat.st_hash_longest)
+		c_mp->stat.st_hash_longest = st_hsearch;
+	c_mp->stat.st_hash_examined += st_hsearch;
+#endif
+
+	/*
+	 * There are 4 possible paths to this location:
+	 *
+	 * FIRST_MISS:
+	 *	Didn't find the page in the hash bucket on our first pass:
+	 *	bhp == NULL, alloc_bhp == NULL
+	 *
+	 * FIRST_FOUND:
+	 *	Found the page in the hash bucket on our first pass:
+	 *	bhp != NULL, alloc_bhp == NULL
+	 *
+	 * SECOND_FOUND:
+	 *	Didn't find the page in the hash bucket on the first pass,
+	 *	allocated space, and found the page in the hash bucket on
+	 *	our second pass:
+	 *	bhp != NULL, alloc_bhp != NULL
+	 *
+	 * SECOND_MISS:
+	 *	Didn't find the page in the hash bucket on the first pass,
+	 *	allocated space, and didn't find the page in the hash bucket
+	 *	on our second pass:
+	 *	bhp == NULL, alloc_bhp != NULL
+	 */
+	state = bhp == NULL ?
+	    (alloc_bhp == NULL ? FIRST_MISS : SECOND_MISS) :
+	    (alloc_bhp == NULL ? FIRST_FOUND : SECOND_FOUND);
+
+	switch (state) {
+	case FIRST_FOUND:
+		/*
+		 * If we are to free the buffer, then this had better be the
+		 * only reference. If so, just free the buffer.  If not,
+		 * complain and get out.
+		 */
+		if (flags == DB_MPOOL_FREE) {
+freebuf:		MUTEX_LOCK(env, hp->mtx_hash);
+			h_locked = 1;
+			if (F_ISSET(bhp, BH_DIRTY)) {
+				F_CLR(bhp, BH_DIRTY | BH_DIRTY_CREATE);
+				DB_ASSERT(env,
+				   atomic_read(&hp->hash_page_dirty) > 0);
+				atomic_dec(env, &hp->hash_page_dirty);
+			}
+
+			/*
+			 * If the buffer we found is already freed, we're done.
+			 * If the ref count is not 1 then someone may be
+			 * peeking at the buffer.  We cannot free it until they
+			 * determine that it is not what they want.  Clear the
+			 * buffer so that waiting threads get an empty page.
+			 */
+			if (F_ISSET(bhp, BH_FREED))
+				goto done;
+			else if (F_ISSET(bhp, BH_FROZEN))
+				makecopy = 1;
+
+			if (makecopy)
+				break;
+			else if (BH_REFCOUNT(bhp) != 1 ||
+			    !SH_CHAIN_SINGLETON(bhp, vc)) {
+				/*
+				 * Create an empty page in the chain for
+				 * subsequent gets.  Otherwise, a thread that
+				 * re-creates this page while it is still in
+				 * cache will see stale data.
+				 */
+				F_SET(bhp, BH_FREED);
+				F_CLR(bhp, BH_TRASH);
+			} else {
+				ret = __memp_bhfree(dbmp, infop, mfp,
+				    hp, bhp, BH_FREE_FREEMEM);
+				bhp = NULL;
+				b_incr = b_lock = h_locked = 0;
+			}
+			goto done;
+		} else if (F_ISSET(bhp, BH_FREED)) {
+revive:			DB_ASSERT(env,
+			    flags == DB_MPOOL_CREATE || flags == DB_MPOOL_NEW);
+			makecopy = makecopy ||
+			    (mvcc && !BH_OWNED_BY(env, bhp, txn)) ||
+			    F_ISSET(bhp, BH_FROZEN);
+			if (flags == DB_MPOOL_CREATE) {
+				MUTEX_LOCK(env, mfp->mutex);
+				if (*pgnoaddr > mfp->last_pgno)
+					mfp->last_pgno = *pgnoaddr;
+				MUTEX_UNLOCK(env, mfp->mutex);
+			}
+		}
+		if (mvcc) {
+			/*
+			 * With multiversion databases, we might need to
+			 * allocate a new buffer into which we can copy the one
+			 * that we found.  In that case, check the last buffer
+			 * in the chain to see whether we can reuse an obsolete
+			 * buffer.
+			 *
+			 * To provide snapshot isolation, we need to make sure
+			 * that we've seen a buffer older than the oldest
+			 * snapshot read LSN.
+			 */
+reuse:			if ((makecopy || F_ISSET(bhp, BH_FROZEN)) &&
+			    !h_locked) {
+				MUTEX_LOCK(env, hp->mtx_hash);
+				h_locked = 1;
+			}
+			if ((makecopy || F_ISSET(bhp, BH_FROZEN)) &&
+			    SH_CHAIN_HASPREV(bhp, vc)) {
+				oldest_bhp = SH_CHAIN_PREVP(bhp, vc, __bh);
+				while (SH_CHAIN_HASPREV(oldest_bhp, vc))
+					oldest_bhp = SH_CHAIN_PREVP(
+					    oldest_bhp, vc, __bh);
+
+				if (BH_REFCOUNT(oldest_bhp) == 0 &&
+				    !BH_OBSOLETE(
+				    oldest_bhp, hp->old_reader, vlsn) &&
+				    (ret = __txn_oldest_reader(env,
+				    &hp->old_reader)) != 0)
+					goto err;
+
+				if (BH_OBSOLETE(
+				    oldest_bhp, hp->old_reader, vlsn) &&
+				    BH_REFCOUNT(oldest_bhp) == 0) {
+					DB_ASSERT(env,
+					    !F_ISSET(oldest_bhp, BH_DIRTY));
+					atomic_inc(env, &oldest_bhp->ref);
+					if (F_ISSET(oldest_bhp, BH_FROZEN)) {
+						/*
+						 * This call will release the
+						 * hash bucket mutex.
+						 */
+						ret = __memp_bh_thaw(dbmp,
+						    infop, hp, oldest_bhp,
+						    NULL);
+						h_locked = 0;
+						if (ret != 0)
+							goto err;
+						goto reuse;
+					}
+					if ((ret = __memp_bhfree(dbmp,
+					    infop, mfp, hp, oldest_bhp,
+					    BH_FREE_REUSE)) != 0)
+						goto err;
+					alloc_bhp = oldest_bhp;
+					h_locked = 0;
+				}
+
+				DB_ASSERT(env, alloc_bhp == NULL ||
+				    !F_ISSET(alloc_bhp, BH_FROZEN));
+			}
+		}
+
+		/* We found the buffer or we're ready to copy -- we're done. */
+		if (!(makecopy || F_ISSET(bhp, BH_FROZEN)) || alloc_bhp != NULL)
+			break;
+
+		/* FALLTHROUGH */
+	case FIRST_MISS:
+		/*
+		 * We didn't find the buffer in our first check.  Figure out
+		 * if the page exists, and allocate structures so we can add
+		 * the page to the buffer pool.
+		 */
+		if (h_locked)
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+		h_locked = 0;
+
+		/*
+		 * The buffer is not in the pool, so we don't need to free it.
+		 */
+		if (LF_ISSET(DB_MPOOL_FREE) &&
+		    (bhp == NULL || F_ISSET(bhp, BH_FREED) || !makecopy))
+			goto done;
+
+		if (bhp != NULL)
+			goto alloc;
+
+newpg:		/*
+		 * If DB_MPOOL_NEW is set, we have to allocate a page number.
+		 * If neither DB_MPOOL_CREATE or DB_MPOOL_NEW is set, then
+		 * it's an error to try and get a page past the end of file.
+		 */
+		DB_ASSERT(env, !h_locked);
+		MUTEX_LOCK(env, mfp->mutex);
+		switch (flags) {
+		case DB_MPOOL_NEW:
+			extending = 1;
+			if (mfp->maxpgno != 0 &&
+			    mfp->last_pgno >= mfp->maxpgno) {
+				__db_errx(env, "%s: file limited to %lu pages",
+				    __memp_fn(dbmfp), (u_long)mfp->maxpgno);
+				ret = ENOSPC;
+			} else
+				*pgnoaddr = mfp->last_pgno + 1;
+			break;
+		case DB_MPOOL_CREATE:
+			if (mfp->maxpgno != 0 && *pgnoaddr > mfp->maxpgno) {
+				__db_errx(env, "%s: file limited to %lu pages",
+				    __memp_fn(dbmfp), (u_long)mfp->maxpgno);
+				ret = ENOSPC;
+			} else if (!extending)
+				extending = *pgnoaddr > mfp->last_pgno;
+			break;
+		default:
+			ret = *pgnoaddr > mfp->last_pgno ? DB_PAGE_NOTFOUND : 0;
+			break;
+		}
+		MUTEX_UNLOCK(env, mfp->mutex);
+		if (ret != 0)
+			goto err;
+
+		/*
+		 * !!!
+		 * In the DB_MPOOL_NEW code path, hp, infop and c_mp have
+		 * not yet been initialized.
+		 */
+		if (hp == NULL) {
+			MP_GET_BUCKET(env,
+			    mfp, *pgnoaddr, &infop, hp, bucket, ret);
+			if (ret != 0)
+				goto err;
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+			c_mp = infop->primary;
+		}
+
+alloc:		/* Allocate a new buffer header and data space. */
+		if (alloc_bhp == NULL && (ret =
+		    __memp_alloc(dbmp, infop, mfp, 0, NULL, &alloc_bhp)) != 0)
+			goto err;
+
+		/* Initialize enough so we can call __memp_bhfree. */
+		alloc_bhp->flags = 0;
+		atomic_init(&alloc_bhp->ref, 1);
+#ifdef DIAGNOSTIC
+		if ((uintptr_t)alloc_bhp->buf & (sizeof(size_t) - 1)) {
+			__db_errx(env,
+		    "DB_MPOOLFILE->get: buffer data is NOT size_t aligned");
+			ret = __env_panic(env, EINVAL);
+			goto err;
+		}
+#endif
+
+		/*
+		 * If we're doing copy-on-write, we will already have the
+		 * buffer header.  In that case, we don't need to search again.
+		 */
+		if (bhp != NULL)
+			break;
+
+		/*
+		 * If we are extending the file, we'll need the mfp lock
+		 * again.
+		 */
+		if (extending)
+			MUTEX_LOCK(env, mfp->mutex);
+
+		/*
+		 * DB_MPOOL_NEW does not guarantee you a page unreferenced by
+		 * any other thread of control.  (That guarantee is interesting
+		 * for DB_MPOOL_NEW, unlike DB_MPOOL_CREATE, because the caller
+		 * did not specify the page number, and so, may reasonably not
+		 * have any way to lock the page outside of mpool.) Regardless,
+		 * if we allocate the page, and some other thread of control
+		 * requests the page by number, we will not detect that and the
+		 * thread of control that allocated using DB_MPOOL_NEW may not
+		 * have a chance to initialize the page.  (Note: we *could*
+		 * detect this case if we set a flag in the buffer header which
+		 * guaranteed that no gets of the page would succeed until the
+		 * reference count went to 0, that is, until the creating page
+		 * put the page.)  What we do guarantee is that if two threads
+		 * of control are both doing DB_MPOOL_NEW calls, they won't
+		 * collide, that is, they won't both get the same page.
+		 *
+		 * There's a possibility that another thread allocated the page
+		 * we were planning to allocate while we were off doing buffer
+		 * allocation.  We can do that by making sure the page number
+		 * we were going to use is still available.  If it's not, then
+		 * we check to see if the next available page number hashes to
+		 * the same mpool region as the old one -- if it does, we can
+		 * continue, otherwise, we have to start over.
+		 */
+		if (flags == DB_MPOOL_NEW && *pgnoaddr != mfp->last_pgno + 1) {
+			*pgnoaddr = mfp->last_pgno + 1;
+			MP_GET_REGION(dbmfp, *pgnoaddr, &t_infop, ret);
+			if (ret != 0)
+				goto err;
+			if (t_infop != infop) {
+				/*
+				 * flags == DB_MPOOL_NEW, so extending is set
+				 * and we're holding the mfp locked.
+				 */
+				MUTEX_UNLOCK(env, mfp->mutex);
+				goto newpg;
+			}
+		}
+
+		/*
+		 * We released the mfp lock, so another thread might have
+		 * extended the file.  Update the last_pgno and initialize
+		 * the file, as necessary, if we extended the file.
+		 */
+		if (extending) {
+			if (*pgnoaddr > mfp->last_pgno)
+				mfp->last_pgno = *pgnoaddr;
+			MUTEX_UNLOCK(env, mfp->mutex);
+			if (ret != 0)
+				goto err;
+		}
+		goto retry;
+	case SECOND_FOUND:
+		/*
+		 * We allocated buffer space for the requested page, but then
+		 * found the page in the buffer cache on our second check.
+		 * That's OK -- we can use the page we found in the pool,
+		 * unless DB_MPOOL_NEW is set.  If we're about to copy-on-write,
+		 * this is exactly the situation we want.
+		 *
+		 * For multiversion files, we may have left some pages in cache
+		 * beyond the end of a file after truncating.  In that case, we
+		 * would get to here with extending set.  If so, we need to
+		 * insert the new page in the version chain similar to when
+		 * we copy on write.
+		 */
+		if (F_ISSET(bhp, BH_FREED) &&
+		    (flags == DB_MPOOL_NEW || flags == DB_MPOOL_CREATE))
+			goto revive;
+		else if (flags == DB_MPOOL_FREE)
+			goto freebuf;
+		else if (makecopy || F_ISSET(bhp, BH_FROZEN))
+			break;
+
+		/*
+		 * We can't use the page we found in the pool if DB_MPOOL_NEW
+		 * was set.  (For details, see the above comment beginning
+		 * "DB_MPOOL_NEW does not guarantee you a page unreferenced by
+		 * any other thread of control".)  If DB_MPOOL_NEW is set, we
+		 * release our pin on this particular buffer, and try to get
+		 * another one.
+		 */
+		if (flags == DB_MPOOL_NEW) {
+			DB_ASSERT(env, b_incr && BH_REFCOUNT(bhp) != 0);
+			atomic_dec(env, &bhp->ref);
+			b_incr = 0;
+			if (F_ISSET(bhp, BH_EXCLUSIVE))
+				F_CLR(bhp, BH_EXCLUSIVE);
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			b_lock = 0;
+			bhp = NULL;
+			goto newpg;
+		}
+
+		break;
+	case SECOND_MISS:
+		/*
+		 * We allocated buffer space for the requested page, and found
+		 * the page still missing on our second pass through the buffer
+		 * cache.  Instantiate the page.
+		 */
+		DB_ASSERT(env, alloc_bhp != NULL);
+		bhp = alloc_bhp;
+		alloc_bhp = NULL;
+
+		/*
+		 * Initialize all the BH and hash bucket fields so we can call
+		 * __memp_bhfree if an error occurs.
+		 *
+		 * Append the buffer to the tail of the bucket list.
+		 */
+		bhp->priority = UINT32_MAX;
+		bhp->pgno = *pgnoaddr;
+		bhp->mf_offset = mf_offset;
+		bhp->bucket = bucket;
+		bhp->region = (int)(infop - dbmp->reginfo);
+		bhp->td_off = INVALID_ROFF;
+		SH_CHAIN_INIT(bhp, vc);
+		bhp->flags = 0;
+
+		/*
+		 * Reference the buffer and lock exclusive.  We either
+		 * need to read the buffer or create it from scratch
+		 * and don't want anyone looking at it till we do.
+		 */
+		MUTEX_LOCK(env, bhp->mtx_buf);
+		b_lock = 1;
+		F_SET(bhp, BH_EXCLUSIVE);
+		b_incr = 1;
+
+		/* We created a new page, it starts dirty. */
+		if (extending) {
+			atomic_inc(env, &hp->hash_page_dirty);
+			F_SET(bhp, BH_DIRTY | BH_DIRTY_CREATE);
+		}
+
+		MUTEX_REQUIRED(env, hp->mtx_hash);
+		SH_TAILQ_INSERT_HEAD(&hp->hash_bucket, bhp, hq, __bh);
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		h_locked = 0;
+
+		/*
+		 * If we created the page, zero it out.  If we didn't create
+		 * the page, read from the backing file.
+		 *
+		 * !!!
+		 * DB_MPOOL_NEW doesn't call the pgin function.
+		 *
+		 * If DB_MPOOL_CREATE is used, then the application's pgin
+		 * function has to be able to handle pages of 0's -- if it
+		 * uses DB_MPOOL_NEW, it can detect all of its page creates,
+		 * and not bother.
+		 *
+		 * If we're running in diagnostic mode, smash any bytes on the
+		 * page that are unknown quantities for the caller.
+		 *
+		 * Otherwise, read the page into memory, optionally creating it
+		 * if DB_MPOOL_CREATE is set.
+		 */
+		if (extending) {
+			MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize,
+			    PROT_READ | PROT_WRITE);
+			memset(bhp->buf, 0,
+			    (mfp->clear_len == DB_CLEARLEN_NOTSET) ?
+			    mfp->stat.st_pagesize : mfp->clear_len);
+#if defined(DIAGNOSTIC) || defined(UMRW)
+			if (mfp->clear_len != DB_CLEARLEN_NOTSET)
+				memset(bhp->buf + mfp->clear_len, CLEAR_BYTE,
+				    mfp->stat.st_pagesize - mfp->clear_len);
+#endif
+
+			if (flags == DB_MPOOL_CREATE && mfp->ftype != 0 &&
+			    (ret = __memp_pg(dbmfp,
+			    bhp->pgno, bhp->buf, 1)) != 0)
+				goto err;
+
+			STAT(++mfp->stat.st_page_create);
+		} else {
+			F_SET(bhp, BH_TRASH);
+			STAT(++mfp->stat.st_cache_miss);
+		}
+
+		makecopy = mvcc && dirty && !extending;
+
+		/* Increment buffer count referenced by MPOOLFILE. */
+		MUTEX_LOCK(env, mfp->mutex);
+		++mfp->block_cnt;
+		MUTEX_UNLOCK(env, mfp->mutex);
+	}
+
+	DB_ASSERT(env, bhp != NULL && BH_REFCOUNT(bhp) != 0 && b_lock);
+	DB_ASSERT(env, !F_ISSET(bhp, BH_FROZEN) || !F_ISSET(bhp, BH_FREED) ||
+	    makecopy);
+
+	/* We've got a buffer header we're re-instantiating. */
+	if (F_ISSET(bhp, BH_FROZEN) && !F_ISSET(bhp, BH_FREED)) {
+		if (alloc_bhp == NULL)
+			goto reuse;
+
+		/*
+		 * To thaw the buffer, we must hold the hash bucket mutex,
+		 * and the call to __memp_bh_thaw will release it.
+		 */
+		if (h_locked == 0)
+			MUTEX_LOCK(env, hp->mtx_hash);
+		h_locked = 1;
+
+		/*
+		 * If the empty buffer has been filled in the meantime, don't
+		 * overwrite it.
+		 */
+		if (F_ISSET(bhp, BH_THAWED)) {
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+			h_locked = 0;
+			goto thawed;
+		}
+
+		ret = __memp_bh_thaw(dbmp, infop, hp, bhp, alloc_bhp);
+		bhp = NULL;
+		b_lock = h_locked = 0;
+		if (ret != 0)
+			goto err;
+		bhp = alloc_bhp;
+		alloc_bhp = NULL;
+		MUTEX_REQUIRED(env, bhp->mtx_buf);
+		b_incr = b_lock = 1;
+	}
+
+	/*
+	 * BH_TRASH --
+	 * The buffer we found may need to be filled from the disk.
+	 *
+	 * It's possible for the read function to fail, which means we fail
+	 * as well.  Discard the buffer on failure unless another thread
+	 * is waiting on our I/O to complete.  It's OK to leave the buffer
+	 * around, as the waiting thread will see the BH_TRASH flag set,
+	 * and will also attempt to discard it.  If there's a waiter,
+	 * we need to decrement our reference count.
+	 */
+	if (F_ISSET(bhp, BH_TRASH) &&
+	    flags != DB_MPOOL_FREE && !F_ISSET(bhp, BH_FREED)) {
+		if ((ret = __memp_pgread(dbmfp,
+		    bhp, LF_ISSET(DB_MPOOL_CREATE) ? 1 : 0)) != 0)
+			goto err;
+		DB_ASSERT(env, read_lsnp != NULL || !SH_CHAIN_HASNEXT(bhp, vc));
+	}
+
+	/* Copy-on-write. */
+	if (makecopy) {
+		/*
+		 * If we read a page from disk that we want to modify, we now
+		 * need to make copy, so we now need to allocate another buffer
+		 * to hold the new copy.
+		 */
+		if (alloc_bhp == NULL)
+			goto reuse;
+
+		DB_ASSERT(env, bhp != NULL && alloc_bhp != bhp);
+		DB_ASSERT(env, txn != NULL ||
+		    (F_ISSET(bhp, BH_FROZEN) && F_ISSET(bhp, BH_FREED)));
+		DB_ASSERT(env, (extending || flags == DB_MPOOL_FREE ||
+		    F_ISSET(bhp, BH_FREED)) ||
+		    !F_ISSET(bhp, BH_FROZEN | BH_TRASH));
+		MUTEX_REQUIRED(env, bhp->mtx_buf);
+
+		if (BH_REFCOUNT(bhp) == 1)
+			MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize,
+			    PROT_READ);
+
+		atomic_init(&alloc_bhp->ref, 1);
+		MUTEX_LOCK(env, alloc_bhp->mtx_buf);
+		alloc_bhp->priority = bhp->priority;
+		alloc_bhp->pgno = bhp->pgno;
+		alloc_bhp->bucket = bhp->bucket;
+		alloc_bhp->region = bhp->region;
+		alloc_bhp->mf_offset = bhp->mf_offset;
+		alloc_bhp->td_off = INVALID_ROFF;
+		if (txn == NULL) {
+			DB_ASSERT(env,
+			    F_ISSET(bhp, BH_FROZEN) && F_ISSET(bhp, BH_FREED));
+			if (bhp->td_off != INVALID_ROFF && (ret =
+			    __memp_bh_settxn(dbmp, mfp, alloc_bhp,
+			    BH_OWNER(env, bhp))) != 0)
+				goto err;
+		} else if ((ret =
+		    __memp_bh_settxn(dbmp, mfp, alloc_bhp, td)) != 0)
+			goto err;
+		MVCC_MPROTECT(alloc_bhp->buf, mfp->stat.st_pagesize,
+		    PROT_READ | PROT_WRITE);
+		if (extending ||
+		    F_ISSET(bhp, BH_FREED) || flags == DB_MPOOL_FREE) {
+			memset(alloc_bhp->buf, 0,
+			    (mfp->clear_len == DB_CLEARLEN_NOTSET) ?
+			    mfp->stat.st_pagesize : mfp->clear_len);
+#if defined(DIAGNOSTIC) || defined(UMRW)
+			if (mfp->clear_len != DB_CLEARLEN_NOTSET)
+				memset(alloc_bhp->buf + mfp->clear_len,
+				    CLEAR_BYTE,
+				    mfp->stat.st_pagesize - mfp->clear_len);
+#endif
+		} else
+			memcpy(alloc_bhp->buf, bhp->buf, mfp->stat.st_pagesize);
+		MVCC_MPROTECT(alloc_bhp->buf, mfp->stat.st_pagesize, 0);
+
+		if (h_locked == 0)
+			MUTEX_LOCK(env, hp->mtx_hash);
+		MUTEX_REQUIRED(env, hp->mtx_hash);
+		h_locked = 1;
+
+		alloc_bhp->flags = BH_EXCLUSIVE |
+		    ((flags == DB_MPOOL_FREE) ? BH_FREED :
+		    F_ISSET(bhp, BH_DIRTY | BH_DIRTY_CREATE));
+		DB_ASSERT(env, flags != DB_MPOOL_FREE ||
+		    !F_ISSET(bhp, BH_DIRTY));
+		F_CLR(bhp, BH_DIRTY | BH_DIRTY_CREATE);
+		DB_ASSERT(env, !SH_CHAIN_HASNEXT(bhp, vc));
+		SH_CHAIN_INSERT_AFTER(bhp, alloc_bhp, vc, __bh);
+		SH_TAILQ_INSERT_BEFORE(&hp->hash_bucket,
+		    bhp, alloc_bhp, hq, __bh);
+		SH_TAILQ_REMOVE(&hp->hash_bucket, bhp, hq, __bh);
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		h_locked = 0;
+		DB_ASSERT(env, b_incr && BH_REFCOUNT(bhp) > 0);
+		if (atomic_dec(env, &bhp->ref) == 0) {
+			bhp->priority = c_mp->lru_count;
+			MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize, 0);
+		}
+		F_CLR(bhp, BH_EXCLUSIVE);
+		MUTEX_UNLOCK(env, bhp->mtx_buf);
+
+		bhp = alloc_bhp;
+		DB_ASSERT(env, BH_REFCOUNT(bhp) > 0);
+		b_incr = 1;
+		MUTEX_REQUIRED(env, bhp->mtx_buf);
+		b_lock = 1;
+
+		if (alloc_bhp != oldest_bhp) {
+			MUTEX_LOCK(env, mfp->mutex);
+			++mfp->block_cnt;
+			MUTEX_UNLOCK(env, mfp->mutex);
+		}
+
+		alloc_bhp = NULL;
+	} else if (mvcc && extending &&
+	    (ret = __memp_bh_settxn(dbmp, mfp, bhp, td)) != 0)
+		goto err;
+
+	if (flags == DB_MPOOL_FREE) {
+		DB_ASSERT(env, !SH_CHAIN_HASNEXT(bhp, vc));
+		/* If we have created an empty buffer, it is not returned. */
+		if (!F_ISSET(bhp, BH_FREED))
+			goto freebuf;
+		goto done;
+	}
+
+	/*
+	 * Free the allocated memory, we no longer need it.
+	 */
+	if (alloc_bhp != NULL) {
+		if ((ret = __memp_bhfree(dbmp, infop, NULL,
+		     NULL, alloc_bhp, BH_FREE_FREEMEM | BH_FREE_UNLOCKED)) != 0)
+			goto err;
+		alloc_bhp = NULL;
+	}
+
+	if (dirty || extending ||
+	    (F_ISSET(bhp, BH_FREED) &&
+	    (flags == DB_MPOOL_CREATE || flags == DB_MPOOL_NEW))) {
+		MUTEX_REQUIRED(env, bhp->mtx_buf);
+		if (F_ISSET(bhp, BH_FREED)) {
+			memset(bhp->buf, 0,
+			    (mfp->clear_len == DB_CLEARLEN_NOTSET) ?
+			    mfp->stat.st_pagesize : mfp->clear_len);
+			F_CLR(bhp, BH_FREED);
+		}
+		if (!F_ISSET(bhp, BH_DIRTY)) {
+#ifdef DIAGNOSTIC
+			MUTEX_LOCK(env, hp->mtx_hash);
+#endif
+			DB_ASSERT(env, !SH_CHAIN_HASNEXT(bhp, vc));
+			atomic_inc(env, &hp->hash_page_dirty);
+			F_SET(bhp, BH_DIRTY);
+#ifdef DIAGNOSTIC
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+#endif
+		}
+	} else if (F_ISSET(bhp, BH_EXCLUSIVE)) {
+		F_CLR(bhp, BH_EXCLUSIVE);
+#ifdef HAVE_SHARED_LATCHES
+		MUTEX_UNLOCK(env, bhp->mtx_buf);
+		MUTEX_READLOCK(env, bhp->mtx_buf);
+		/*
+		 * If another thread has dirtied the page while we
+		 * switched locks, we have to go through it all again.
+		 */
+		if (SH_CHAIN_HASNEXT(bhp, vc) && read_lsnp == NULL) {
+			atomic_dec(env, &bhp->ref);
+			b_incr = 0;
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			b_lock = 0;
+			bhp = NULL;
+			goto retry;
+		}
+#endif
+	}
+
+	MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize, PROT_READ |
+	    (dirty || extending || F_ISSET(bhp, BH_DIRTY) ?
+	    PROT_WRITE : 0));
+
+#ifdef DIAGNOSTIC
+	MUTEX_LOCK(env, hp->mtx_hash);
+	{
+	BH *next_bhp = SH_CHAIN_NEXT(bhp, vc, __bh);
+
+	DB_ASSERT(env, !mfp->multiversion || read_lsnp != NULL ||
+	    next_bhp == NULL);
+	DB_ASSERT(env, !mvcc || read_lsnp == NULL ||
+	    bhp->td_off == INVALID_ROFF || BH_OWNED_BY(env, bhp, txn) ||
+	    (BH_VISIBLE(env, bhp, read_lsnp, vlsn) &&
+	    (next_bhp == NULL || F_ISSET(next_bhp, BH_FROZEN) ||
+	    (next_bhp->td_off != INVALID_ROFF &&
+	    (BH_OWNER(env, next_bhp)->status != TXN_COMMITTED ||
+	    IS_ZERO_LSN(BH_OWNER(env, next_bhp)->last_lsn) ||
+	    !BH_VISIBLE(env, next_bhp, read_lsnp, vlsn))))));
+	}
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+#endif
+
+	/*
+	 * Record this pin for this thread.  Holding the page pinned
+	 * without recording the pin is ok since we do not recover from
+	 * a death from within the library itself.
+	 */
+	if (ip != NULL) {
+		reginfo = env->reginfo;
+		if (ip->dbth_pincount == ip->dbth_pinmax) {
+			pinmax = ip->dbth_pinmax;
+			renv = reginfo->primary;
+			MUTEX_LOCK(env, renv->mtx_regenv);
+			if ((ret = __env_alloc(reginfo,
+			    2 * pinmax * sizeof(PIN_LIST), &list)) != 0) {
+				MUTEX_UNLOCK(env, renv->mtx_regenv);
+				goto err;
+			}
+
+			memcpy(list, R_ADDR(reginfo, ip->dbth_pinlist),
+			    pinmax * sizeof(PIN_LIST));
+			memset(&list[pinmax], 0, pinmax * sizeof(PIN_LIST));
+			list_off = R_OFFSET(reginfo, list);
+			list = R_ADDR(reginfo, ip->dbth_pinlist);
+			ip->dbth_pinmax = 2 * pinmax;
+			ip->dbth_pinlist = list_off;
+			if (list != ip->dbth_pinarray)
+				__env_alloc_free(reginfo, list);
+			MUTEX_UNLOCK(env, renv->mtx_regenv);
+		}
+		list = R_ADDR(reginfo, ip->dbth_pinlist);
+		for (lp = list; lp < &list[ip->dbth_pinmax]; lp++)
+			if (lp->b_ref == INVALID_ROFF)
+				break;
+
+		ip->dbth_pincount++;
+		lp->b_ref = R_OFFSET(infop, bhp);
+		lp->region = (int)(infop - dbmp->reginfo);
+	}
+
+#ifdef DIAGNOSTIC
+	/* Update the file's pinned reference count. */
+	MPOOL_SYSTEM_LOCK(env);
+	++dbmfp->pinref;
+	MPOOL_SYSTEM_UNLOCK(env);
+
+	/*
+	 * We want to switch threads as often as possible, and at awkward
+	 * times.  Yield every time we get a new page to ensure contention.
+	 */
+	if (F_ISSET(env->dbenv, DB_ENV_YIELDCPU))
+		__os_yield(env, 0, 0);
+#endif
+
+	DB_ASSERT(env, alloc_bhp == NULL);
+	DB_ASSERT(env, !(dirty || extending) ||
+	    atomic_read(&hp->hash_page_dirty) > 0);
+	DB_ASSERT(env, BH_REFCOUNT(bhp) > 0 &&
+	    !F_ISSET(bhp, BH_FREED | BH_FROZEN | BH_TRASH));
+
+	*(void **)addrp = bhp->buf;
+	return (0);
+
+done:
+err:	/*
+	 * We should only get to here with ret == 0 if freeing a buffer.
+	 * In that case, check that it has in fact been freed.
+	 */
+	DB_ASSERT(env, ret != 0 || flags != DB_MPOOL_FREE || bhp == NULL ||
+	    (F_ISSET(bhp, BH_FREED) && !SH_CHAIN_HASNEXT(bhp, vc)));
+
+	if (bhp != NULL) {
+		if (b_incr)
+			atomic_dec(env, &bhp->ref);
+		if (b_lock) {
+			F_CLR(bhp, BH_EXCLUSIVE);
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+		}
+	}
+
+	if (h_locked)
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+
+	/* If alloc_bhp is set, free the memory. */
+	if (alloc_bhp != NULL)
+		(void)__memp_bhfree(dbmp, infop, NULL,
+		     NULL, alloc_bhp, BH_FREE_FREEMEM | BH_FREE_UNLOCKED);
+
+	return (ret);
+}
diff --git a/mp/mp_fmethod.c b/mp/mp_fmethod.c
new file mode 100644
index 0000000..2acc282
--- /dev/null
+++ b/mp/mp_fmethod.c
@@ -0,0 +1,555 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+
+static int __memp_get_clear_len __P((DB_MPOOLFILE *, u_int32_t *));
+static int __memp_get_lsn_offset __P((DB_MPOOLFILE *, int32_t *));
+static int __memp_get_maxsize __P((DB_MPOOLFILE *, u_int32_t *, u_int32_t *));
+static int __memp_set_maxsize __P((DB_MPOOLFILE *, u_int32_t, u_int32_t));
+static int __memp_get_priority __P((DB_MPOOLFILE *, DB_CACHE_PRIORITY *));
+static int __memp_set_priority __P((DB_MPOOLFILE *, DB_CACHE_PRIORITY));
+
+/*
+ * __memp_fcreate_pp --
+ *	ENV->memp_fcreate pre/post processing.
+ *
+ * PUBLIC: int __memp_fcreate_pp __P((DB_ENV *, DB_MPOOLFILE **, u_int32_t));
+ */
+int
+__memp_fcreate_pp(dbenv, retp, flags)
+	DB_ENV *dbenv;
+	DB_MPOOLFILE **retp;
+	u_int32_t flags;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	/* Validate arguments. */
+	if ((ret = __db_fchk(env, "DB_ENV->memp_fcreate", flags, 0)) != 0)
+		return (ret);
+
+	if (REP_ON(env)) {
+		__db_errx(env,
+  "DB_ENV->memp_fcreate: method not permitted when replication is configured");
+		return (EINVAL);
+	}
+
+	ENV_ENTER(env, ip);
+	ret = __memp_fcreate(env, retp);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_fcreate --
+ *	ENV->memp_fcreate.
+ *
+ * PUBLIC: int __memp_fcreate __P((ENV *, DB_MPOOLFILE **));
+ */
+int
+__memp_fcreate(env, retp)
+	ENV *env;
+	DB_MPOOLFILE **retp;
+{
+	DB_MPOOLFILE *dbmfp;
+	int ret;
+
+	/* Allocate and initialize the per-process structure. */
+	if ((ret = __os_calloc(env, 1, sizeof(DB_MPOOLFILE), &dbmfp)) != 0)
+		return (ret);
+
+	dbmfp->ref = 1;
+	dbmfp->lsn_offset = DB_LSN_OFF_NOTSET;
+	dbmfp->env = env;
+	dbmfp->mfp = INVALID_ROFF;
+
+	dbmfp->close = __memp_fclose_pp;
+	dbmfp->get = __memp_fget_pp;
+	dbmfp->get_clear_len = __memp_get_clear_len;
+	dbmfp->get_fileid = __memp_get_fileid;
+	dbmfp->get_flags = __memp_get_flags;
+	dbmfp->get_ftype = __memp_get_ftype;
+	dbmfp->get_last_pgno = __memp_get_last_pgno;
+	dbmfp->get_lsn_offset = __memp_get_lsn_offset;
+	dbmfp->get_maxsize = __memp_get_maxsize;
+	dbmfp->get_pgcookie = __memp_get_pgcookie;
+	dbmfp->get_priority = __memp_get_priority;
+	dbmfp->open = __memp_fopen_pp;
+	dbmfp->put = __memp_fput_pp;
+	dbmfp->set_clear_len = __memp_set_clear_len;
+	dbmfp->set_fileid = __memp_set_fileid;
+	dbmfp->set_flags = __memp_set_flags;
+	dbmfp->set_ftype = __memp_set_ftype;
+	dbmfp->set_lsn_offset = __memp_set_lsn_offset;
+	dbmfp->set_maxsize = __memp_set_maxsize;
+	dbmfp->set_pgcookie = __memp_set_pgcookie;
+	dbmfp->set_priority = __memp_set_priority;
+	dbmfp->sync = __memp_fsync_pp;
+
+	*retp = dbmfp;
+	return (0);
+}
+
+/*
+ * __memp_get_clear_len --
+ *	Get the clear length.
+ */
+static int
+__memp_get_clear_len(dbmfp, clear_lenp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t *clear_lenp;
+{
+	*clear_lenp = dbmfp->clear_len;
+	return (0);
+}
+
+/*
+ * __memp_set_clear_len --
+ *	DB_MPOOLFILE->set_clear_len.
+ *
+ * PUBLIC: int __memp_set_clear_len __P((DB_MPOOLFILE *, u_int32_t));
+ */
+int
+__memp_set_clear_len(dbmfp, clear_len)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t clear_len;
+{
+	MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_clear_len");
+
+	dbmfp->clear_len = clear_len;
+	return (0);
+}
+
+/*
+ * __memp_get_fileid --
+ *	DB_MPOOLFILE->get_fileid.
+ *
+ * PUBLIC: int __memp_get_fileid __P((DB_MPOOLFILE *, u_int8_t *));
+ */
+int
+__memp_get_fileid(dbmfp, fileid)
+	DB_MPOOLFILE *dbmfp;
+	u_int8_t *fileid;
+{
+	if (!F_ISSET(dbmfp, MP_FILEID_SET)) {
+		__db_errx(dbmfp->env, "get_fileid: file ID not set");
+		return (EINVAL);
+	}
+
+	memcpy(fileid, dbmfp->fileid, DB_FILE_ID_LEN);
+	return (0);
+}
+
+/*
+ * __memp_set_fileid --
+ *	DB_MPOOLFILE->set_fileid.
+ *
+ * PUBLIC: int __memp_set_fileid __P((DB_MPOOLFILE *, u_int8_t *));
+ */
+int
+__memp_set_fileid(dbmfp, fileid)
+	DB_MPOOLFILE *dbmfp;
+	u_int8_t *fileid;
+{
+	MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_fileid");
+
+	memcpy(dbmfp->fileid, fileid, DB_FILE_ID_LEN);
+	F_SET(dbmfp, MP_FILEID_SET);
+
+	return (0);
+}
+
+/*
+ * __memp_get_flags --
+ *	Get the DB_MPOOLFILE flags;
+ *
+ * PUBLIC: int __memp_get_flags __P((DB_MPOOLFILE *, u_int32_t *));
+ */
+int
+__memp_get_flags(dbmfp, flagsp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t *flagsp;
+{
+	MPOOLFILE *mfp;
+
+	mfp = dbmfp->mfp;
+
+	*flagsp = 0;
+
+	if (mfp == NULL)
+		*flagsp = FLD_ISSET(dbmfp->config_flags,
+		     DB_MPOOL_NOFILE | DB_MPOOL_UNLINK);
+	else {
+		if (mfp->no_backing_file)
+			FLD_SET(*flagsp, DB_MPOOL_NOFILE);
+		if (mfp->unlink_on_close)
+			FLD_SET(*flagsp, DB_MPOOL_UNLINK);
+	}
+	return (0);
+}
+
+/*
+ * __memp_set_flags --
+ *	Set the DB_MPOOLFILE flags;
+ *
+ * PUBLIC: int __memp_set_flags __P((DB_MPOOLFILE *, u_int32_t, int));
+ */
+int
+__memp_set_flags(dbmfp, flags, onoff)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t flags;
+	int onoff;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+	int ret;
+
+	env = dbmfp->env;
+	mfp = dbmfp->mfp;
+
+	switch (flags) {
+	case DB_MPOOL_NOFILE:
+		if (mfp == NULL)
+			if (onoff)
+				FLD_SET(dbmfp->config_flags, DB_MPOOL_NOFILE);
+			else
+				FLD_CLR(dbmfp->config_flags, DB_MPOOL_NOFILE);
+		else
+			mfp->no_backing_file = onoff;
+		break;
+	case DB_MPOOL_UNLINK:
+		if (mfp == NULL)
+			if (onoff)
+				FLD_SET(dbmfp->config_flags, DB_MPOOL_UNLINK);
+			else
+				FLD_CLR(dbmfp->config_flags, DB_MPOOL_UNLINK);
+		else
+			mfp->unlink_on_close = onoff;
+		break;
+	default:
+		if ((ret = __db_fchk(env, "DB_MPOOLFILE->set_flags",
+		    flags, DB_MPOOL_NOFILE | DB_MPOOL_UNLINK)) != 0)
+			return (ret);
+		break;
+	}
+	return (0);
+}
+
+/*
+ * __memp_get_ftype --
+ *	Get the file type (as registered).
+ *
+ * PUBLIC: int __memp_get_ftype __P((DB_MPOOLFILE *, int *));
+ */
+int
+__memp_get_ftype(dbmfp, ftypep)
+	DB_MPOOLFILE *dbmfp;
+	int *ftypep;
+{
+	*ftypep = dbmfp->ftype;
+	return (0);
+}
+
+/*
+ * __memp_set_ftype --
+ *	DB_MPOOLFILE->set_ftype.
+ *
+ * PUBLIC: int __memp_set_ftype __P((DB_MPOOLFILE *, int));
+ */
+int
+__memp_set_ftype(dbmfp, ftype)
+	DB_MPOOLFILE *dbmfp;
+	int ftype;
+{
+	MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_ftype");
+
+	dbmfp->ftype = ftype;
+	return (0);
+}
+
+/*
+ * __memp_get_lsn_offset --
+ *	Get the page's LSN offset.
+ */
+static int
+__memp_get_lsn_offset(dbmfp, lsn_offsetp)
+	DB_MPOOLFILE *dbmfp;
+	int32_t *lsn_offsetp;
+{
+	*lsn_offsetp = dbmfp->lsn_offset;
+	return (0);
+}
+
+/*
+ * __memp_set_lsn_offset --
+ *	Set the page's LSN offset.
+ *
+ * PUBLIC: int __memp_set_lsn_offset __P((DB_MPOOLFILE *, int32_t));
+ */
+int
+__memp_set_lsn_offset(dbmfp, lsn_offset)
+	DB_MPOOLFILE *dbmfp;
+	int32_t lsn_offset;
+{
+	MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_lsn_offset");
+
+	dbmfp->lsn_offset = lsn_offset;
+	return (0);
+}
+
+/*
+ * __memp_get_maxsize --
+ *	Get the file's maximum size.
+ */
+static int
+__memp_get_maxsize(dbmfp, gbytesp, bytesp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t *gbytesp, *bytesp;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+
+	if ((mfp = dbmfp->mfp) == NULL) {
+		*gbytesp = dbmfp->gbytes;
+		*bytesp = dbmfp->bytes;
+	} else {
+		env = dbmfp->env;
+
+		MUTEX_LOCK(env, mfp->mutex);
+		*gbytesp = (u_int32_t)
+		    (mfp->maxpgno / (GIGABYTE / mfp->stat.st_pagesize));
+		*bytesp = (u_int32_t)
+		    ((mfp->maxpgno % (GIGABYTE / mfp->stat.st_pagesize)) *
+		    mfp->stat.st_pagesize);
+		MUTEX_UNLOCK(env, mfp->mutex);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_set_maxsize --
+ *	Set the file's maximum size.
+ */
+static int
+__memp_set_maxsize(dbmfp, gbytes, bytes)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t gbytes, bytes;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+
+	if ((mfp = dbmfp->mfp) == NULL) {
+		dbmfp->gbytes = gbytes;
+		dbmfp->bytes = bytes;
+	} else {
+		env = dbmfp->env;
+
+		MUTEX_LOCK(env, mfp->mutex);
+		mfp->maxpgno = (db_pgno_t)
+		    (gbytes * (GIGABYTE / mfp->stat.st_pagesize));
+		mfp->maxpgno += (db_pgno_t)
+		    ((bytes + mfp->stat.st_pagesize - 1) /
+		    mfp->stat.st_pagesize);
+		MUTEX_UNLOCK(env, mfp->mutex);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_get_pgcookie --
+ *	Get the pgin/pgout cookie.
+ *
+ * PUBLIC: int __memp_get_pgcookie __P((DB_MPOOLFILE *, DBT *));
+ */
+int
+__memp_get_pgcookie(dbmfp, pgcookie)
+	DB_MPOOLFILE *dbmfp;
+	DBT *pgcookie;
+{
+	if (dbmfp->pgcookie == NULL) {
+		pgcookie->size = 0;
+		pgcookie->data = "";
+	} else
+		memcpy(pgcookie, dbmfp->pgcookie, sizeof(DBT));
+	return (0);
+}
+
+/*
+ * __memp_set_pgcookie --
+ *	Set the pgin/pgout cookie.
+ *
+ * PUBLIC: int __memp_set_pgcookie __P((DB_MPOOLFILE *, DBT *));
+ */
+int
+__memp_set_pgcookie(dbmfp, pgcookie)
+	DB_MPOOLFILE *dbmfp;
+	DBT *pgcookie;
+{
+	DBT *cookie;
+	ENV *env;
+	int ret;
+
+	MPF_ILLEGAL_AFTER_OPEN(dbmfp, "DB_MPOOLFILE->set_pgcookie");
+	env = dbmfp->env;
+
+	if ((ret = __os_calloc(env, 1, sizeof(*cookie), &cookie)) != 0)
+		return (ret);
+	if ((ret = __os_malloc(env, pgcookie->size, &cookie->data)) != 0) {
+		__os_free(env, cookie);
+		return (ret);
+	}
+
+	memcpy(cookie->data, pgcookie->data, pgcookie->size);
+	cookie->size = pgcookie->size;
+
+	dbmfp->pgcookie = cookie;
+	return (0);
+}
+
+/*
+ * __memp_get_priority --
+ *	Set the cache priority for pages from this file.
+ */
+static int
+__memp_get_priority(dbmfp, priorityp)
+	DB_MPOOLFILE *dbmfp;
+	DB_CACHE_PRIORITY *priorityp;
+{
+	switch (dbmfp->priority) {
+	case MPOOL_PRI_VERY_LOW:
+		*priorityp = DB_PRIORITY_VERY_LOW;
+		break;
+	case MPOOL_PRI_LOW:
+		*priorityp = DB_PRIORITY_LOW;
+		break;
+	case MPOOL_PRI_DEFAULT:
+		*priorityp = DB_PRIORITY_DEFAULT;
+		break;
+	case MPOOL_PRI_HIGH:
+		*priorityp = DB_PRIORITY_HIGH;
+		break;
+	case MPOOL_PRI_VERY_HIGH:
+		*priorityp = DB_PRIORITY_VERY_HIGH;
+		break;
+	default:
+		__db_errx(dbmfp->env,
+		    "DB_MPOOLFILE->get_priority: unknown priority value: %d",
+		    dbmfp->priority);
+		return (EINVAL);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_set_priority --
+ *	Set the cache priority for pages from this file.
+ */
+static int
+__memp_set_priority(dbmfp, priority)
+	DB_MPOOLFILE *dbmfp;
+	DB_CACHE_PRIORITY priority;
+{
+	switch (priority) {
+	case DB_PRIORITY_VERY_LOW:
+		dbmfp->priority = MPOOL_PRI_VERY_LOW;
+		break;
+	case DB_PRIORITY_LOW:
+		dbmfp->priority = MPOOL_PRI_LOW;
+		break;
+	case DB_PRIORITY_DEFAULT:
+		dbmfp->priority = MPOOL_PRI_DEFAULT;
+		break;
+	case DB_PRIORITY_HIGH:
+		dbmfp->priority = MPOOL_PRI_HIGH;
+		break;
+	case DB_PRIORITY_VERY_HIGH:
+		dbmfp->priority = MPOOL_PRI_VERY_HIGH;
+		break;
+	default:
+		__db_errx(dbmfp->env,
+		    "DB_MPOOLFILE->set_priority: unknown priority value: %d",
+		    priority);
+		return (EINVAL);
+	}
+
+	/* Update the underlying file if we've already opened it. */
+	if (dbmfp->mfp != NULL)
+		dbmfp->mfp->priority = dbmfp->priority;
+
+	return (0);
+}
+
+/*
+ * __memp_get_last_pgno --
+ *	Return the page number of the last page in the file.
+ *
+ * !!!
+ * The method is undocumented, but the handle is exported, users occasionally
+ * ask for it.
+ *
+ * PUBLIC: int __memp_get_last_pgno __P((DB_MPOOLFILE *, db_pgno_t *));
+ */
+int
+__memp_get_last_pgno(dbmfp, pgnoaddr)
+	DB_MPOOLFILE *dbmfp;
+	db_pgno_t *pgnoaddr;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+
+	env = dbmfp->env;
+	mfp = dbmfp->mfp;
+
+	MUTEX_LOCK(env, mfp->mutex);
+	*pgnoaddr = mfp->last_pgno;
+	MUTEX_UNLOCK(env, mfp->mutex);
+
+	return (0);
+}
+
+/*
+ * __memp_fn --
+ *	On errors we print whatever is available as the file name.
+ *
+ * PUBLIC: char * __memp_fn __P((DB_MPOOLFILE *));
+ */
+char *
+__memp_fn(dbmfp)
+	DB_MPOOLFILE *dbmfp;
+{
+	return (__memp_fns(dbmfp->env->mp_handle, dbmfp->mfp));
+}
+
+/*
+ * __memp_fns --
+ *	On errors we print whatever is available as the file name.
+ *
+ * PUBLIC: char * __memp_fns __P((DB_MPOOL *, MPOOLFILE *));
+ *
+ */
+char *
+__memp_fns(dbmp, mfp)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+{
+	if (mfp == NULL || mfp->path_off == 0)
+		return ((char *)"unknown");
+
+	return ((char *)R_ADDR(dbmp->reginfo, mfp->path_off));
+}
diff --git a/mp/mp_fopen.c b/mp/mp_fopen.c
new file mode 100644
index 0000000..48a7d5b
--- /dev/null
+++ b/mp/mp_fopen.c
@@ -0,0 +1,1100 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/db_page.h"
+#include "dbinc/hash.h"
+
+static int __memp_mpf_alloc __P((DB_MPOOL *,
+    DB_MPOOLFILE *, const char *, u_int32_t, u_int32_t, MPOOLFILE **));
+static int __memp_mpf_find __P((ENV *,
+    DB_MPOOLFILE *, DB_MPOOL_HASH *, const char *, u_int32_t, MPOOLFILE **));
+
+/*
+ * __memp_fopen_pp --
+ *	DB_MPOOLFILE->open pre/post processing.
+ *
+ * PUBLIC: int __memp_fopen_pp
+ * PUBLIC:     __P((DB_MPOOLFILE *, const char *, u_int32_t, int, size_t));
+ */
+int
+__memp_fopen_pp(dbmfp, path, flags, mode, pagesize)
+	DB_MPOOLFILE *dbmfp;
+	const char *path;
+	u_int32_t flags;
+	int mode;
+	size_t pagesize;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbmfp->env;
+
+	/* Validate arguments. */
+	if ((ret = __db_fchk(env, "DB_MPOOLFILE->open", flags,
+	    DB_CREATE | DB_DIRECT | DB_EXTENT | DB_MULTIVERSION |
+	    DB_NOMMAP | DB_ODDFILESIZE | DB_RDONLY | DB_TRUNCATE)) != 0)
+		return (ret);
+
+	/*
+	 * Require a non-zero, power-of-two pagesize, smaller than the
+	 * clear length.
+	 */
+	if (pagesize == 0 || !POWER_OF_TWO(pagesize)) {
+		__db_errx(env,
+		    "DB_MPOOLFILE->open: page sizes must be a power-of-2");
+		return (EINVAL);
+	}
+	if (dbmfp->clear_len > pagesize) {
+		__db_errx(env,
+		    "DB_MPOOLFILE->open: clear length larger than page size");
+		return (EINVAL);
+	}
+
+	/* Read-only checks, and local flag. */
+	if (LF_ISSET(DB_RDONLY) && path == NULL) {
+		__db_errx(env,
+		    "DB_MPOOLFILE->open: temporary files can't be readonly");
+		return (EINVAL);
+	}
+
+	if (LF_ISSET(DB_MULTIVERSION) && !TXN_ON(env)) {
+		__db_errx(env,
+		   "DB_MPOOLFILE->open: DB_MULTIVERSION requires transactions");
+		return (EINVAL);
+	}
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env,
+	    (__memp_fopen(dbmfp, NULL,
+	    path, NULL, flags, mode, pagesize)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_fopen --
+ *	DB_MPOOLFILE->open.
+ *
+ * PUBLIC: int __memp_fopen __P((DB_MPOOLFILE *, MPOOLFILE *,
+ * PUBLIC:     const char *, const char **, u_int32_t, int, size_t));
+ */
+int
+__memp_fopen(dbmfp, mfp, path, dirp, flags, mode, pgsize)
+	DB_MPOOLFILE *dbmfp;
+	MPOOLFILE *mfp;
+	const char *path;
+	const char **dirp;
+	u_int32_t flags;
+	int mode;
+	size_t pgsize;
+{
+	DB_ENV *dbenv;
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *tmp_dbmfp;
+	DB_MPOOL_HASH *hp;
+	ENV *env;
+	MPOOL *mp;
+	MPOOLFILE *alloc_mfp;
+	size_t maxmap;
+	db_pgno_t last_pgno;
+	u_int32_t bucket, mbytes, bytes, oflags, pagesize;
+	int refinc, ret;
+	char *rpath;
+
+	/* If this handle is already open, return. */
+	if (F_ISSET(dbmfp, MP_OPEN_CALLED))
+		return (0);
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	dbenv = env->dbenv;
+	mp = dbmp->reginfo[0].primary;
+	alloc_mfp = NULL;
+	mbytes = bytes = 0;
+	refinc = ret = 0;
+	rpath = NULL;
+
+	/*
+	 * We're keeping the page size as a size_t in the public API, but
+	 * it's a u_int32_t everywhere internally.
+	 */
+	pagesize = (u_int32_t)pgsize;
+
+	/*
+	 * We're called internally with a specified mfp, in which case the
+	 * path is NULL, but we'll get the path from the underlying region
+	 * information.  Otherwise, if the path is NULL, it's a temporary
+	 * file -- we know we can't join any existing files, and we'll delay
+	 * the open until we actually need to write the file. All temporary
+	 * files will go into the first hash bucket.
+	 */
+	DB_ASSERT(env, mfp == NULL || path == NULL);
+
+	bucket = 0;
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+	if (mfp == NULL) {
+		if (path == NULL)
+			goto alloc;
+
+		/*
+		 * Hash to the proper file table entry and walk it.
+		 *
+		 * The fileID is a filesystem unique number (e.g., a
+		 * UNIX dev/inode pair) plus a timestamp.  If files are
+		 * removed and created in less than a second, the fileID
+		 * can be repeated.  The problem with repetition happens
+		 * when the file that previously had the fileID value still
+		 * has pages in the pool, since we don't want to use them
+		 * to satisfy requests for the new file. Because the
+		 * DB_TRUNCATE flag reuses the dev/inode pair, repeated
+		 * opens with that flag set guarantees matching fileIDs
+		 * when the machine can open a file and then re-open
+		 * with truncate within a second.  For this reason, we
+		 * pass that flag down, and, if we find a matching entry,
+		 * we ensure that it's never found again, and we create
+		 * a new entry for the current request.
+		 */
+
+		if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE))
+			bucket = FNBUCKET(path, strlen(path));
+		else
+			bucket = FNBUCKET(dbmfp->fileid, DB_FILE_ID_LEN);
+		hp += bucket;
+
+		/*
+		 * If we are passed a FILEID find the MPOOLFILE and inc
+		 * its ref count.  That way it cannot go away while we
+		 * open it.
+		 */
+		if (F_ISSET(dbmfp, MP_FILEID_SET)) {
+			MUTEX_LOCK(env, hp->mtx_hash);
+			ret =
+			    __memp_mpf_find(env, dbmfp, hp, path, flags,&mfp);
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+			if (ret != 0)
+				goto err;
+			if (mfp != NULL)
+				refinc = 1;
+		}
+	} else {
+		/*
+		 * Deadfile can only be set if mpf_cnt goes to zero (or if we
+		 * failed creating the file DB_AM_DISCARD).  Increment the ref
+		 * count so the file cannot become dead and be unlinked.
+		 */
+		MUTEX_LOCK(env, mfp->mutex);
+		if (!mfp->deadfile) {
+			++mfp->mpf_cnt;
+			refinc = 1;
+		}
+		MUTEX_UNLOCK(env, mfp->mutex);
+
+		/*
+		 * Test one last time to see if the file is dead -- it may have
+		 * been removed.  This happens when a checkpoint trying to open
+		 * the file to flush a buffer races with the Db::remove method.
+		 * The error will be ignored, so don't output an error message.
+		 */
+		if (mfp->deadfile)
+			return (EINVAL);
+	}
+
+	/*
+	 * If there's no backing file, we can join existing files in the cache,
+	 * but there's nothing to read from disk.
+	 */
+	if (!FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE)) {
+		/* Convert MP open flags to DB OS-layer open flags. */
+		oflags = 0;
+		if (LF_ISSET(DB_CREATE))
+			oflags |= DB_OSO_CREATE;
+		if (LF_ISSET(DB_DIRECT))
+			oflags |= DB_OSO_DIRECT;
+		if (LF_ISSET(DB_RDONLY)) {
+			F_SET(dbmfp, MP_READONLY);
+			oflags |= DB_OSO_RDONLY;
+		}
+
+		/*
+		 * XXX
+		 * A grievous layering violation, the DB_DSYNC_DB flag
+		 * was left in the ENV structure and not driven through
+		 * the cache API.  This needs to be fixed when the general
+		 * API configuration is fixed.
+		 */
+		if (F_ISSET(env->dbenv, DB_ENV_DSYNC_DB))
+			oflags |= DB_OSO_DSYNC;
+
+		/*
+		 * Get the real name for this file and open it.
+		 *
+		 * Supply a page size so os_open can decide whether to
+		 * turn buffering off if the DB_DIRECT_DB flag is set.
+		 *
+		 * Acquire the region lock if we're using a path from
+		 * an underlying MPOOLFILE -- there's a race in accessing
+		 * the path name stored in the region, __memp_nameop may
+		 * be simultaneously renaming the file.
+		 */
+		if (mfp != NULL) {
+			MPOOL_SYSTEM_LOCK(env);
+			path = R_ADDR(dbmp->reginfo, mfp->path_off);
+		}
+		if ((ret = __db_appname(env,
+		     DB_APP_DATA, path, dirp, &rpath)) == 0)
+			ret = __os_open(env, rpath,
+			     (u_int32_t)pagesize, oflags, mode, &dbmfp->fhp);
+		if (mfp != NULL)
+			MPOOL_SYSTEM_UNLOCK(env);
+		if (ret != 0)
+			goto err;
+
+		/*
+		 * Cache file handles are shared, and have mutexes to
+		 * protect the underlying file handle across seek and
+		 * read/write calls.
+		 */
+		dbmfp->fhp->ref = 1;
+		if ((ret = __mutex_alloc(env, MTX_MPOOL_FH,
+		     DB_MUTEX_PROCESS_ONLY, &dbmfp->fhp->mtx_fh)) != 0)
+			goto err;
+
+		/*
+		 * Figure out the file's size.
+		 *
+		 * !!!
+		 * We can't use off_t's here, or in any code in the mainline
+		 * library for that matter.  (We have to use them in the
+		 * os stubs, of course, as there are system calls that
+		 * take them as arguments.)  The reason is some customers
+		 * build in environments where an off_t is 32-bits, but
+		 * still run where offsets are 64-bits, and they pay us
+		 * a lot of money.
+		 */
+		if ((ret = __os_ioinfo(
+		    env, rpath, dbmfp->fhp, &mbytes, &bytes, NULL)) != 0) {
+			__db_err(env, ret, "%s", rpath);
+			goto err;
+		}
+
+		/*
+		 * Don't permit files that aren't a multiple of the pagesize,
+		 * and find the number of the last page in the file, all the
+		 * time being careful not to overflow 32 bits.
+		 *
+		 * During verify or recovery, we might have to cope with a
+		 * truncated file; if the file size is not a multiple of the
+		 * page size, round down to a page, we'll take care of the
+		 * partial page outside the mpool system.
+		 */
+		DB_ASSERT(env, pagesize != 0);
+		if (bytes % pagesize != 0) {
+			if (LF_ISSET(DB_ODDFILESIZE))
+				bytes -= (u_int32_t)(bytes % pagesize);
+			else {
+				__db_errx(env,
+		    "%s: file size not a multiple of the pagesize", rpath);
+				ret = EINVAL;
+				goto err;
+			}
+		}
+
+		/*
+		 * Get the file id if we weren't given one.  Generated file id's
+		 * don't use timestamps, otherwise there'd be no chance of any
+		 * other process joining the party.  Don't bother looking for
+		 * this id in the hash table, its new.
+		 */
+		if (mfp == NULL && !F_ISSET(dbmfp, MP_FILEID_SET)) {
+			if  ((ret =
+			     __os_fileid(env, rpath, 0, dbmfp->fileid)) != 0)
+				goto err;
+			F_SET(dbmfp, MP_FILEID_SET);
+			goto alloc;
+		}
+	}
+
+	if (mfp != NULL)
+		goto have_mfp;
+
+	/*
+	 * We can race with another process opening the same file when
+	 * we allocate the mpoolfile structure.  We will come back
+	 * here and check the hash table again to see if it has appeared.
+	 * For most files this is not a problem, since the name is locked
+	 * at a higher layer but QUEUE extent files are not locked.
+	 */
+check:	MUTEX_LOCK(env, hp->mtx_hash);
+	if ((ret = __memp_mpf_find(env, dbmfp, hp, path, flags, &mfp) != 0))
+		goto err;
+
+	if (alloc_mfp != NULL && mfp == NULL) {
+		mfp = alloc_mfp;
+		alloc_mfp = NULL;
+		SH_TAILQ_INSERT_HEAD(&hp->hash_bucket, mfp, q, __mpoolfile);
+	} else if (mfp != NULL) {
+		/*
+		 * Some things about a file cannot be changed: the clear length,
+		 * page size, or LSN location.  However, if this is an attempt
+		 * to open a named in-memory file, we may not yet have that
+		 * information. so accept uninitialized entries.
+		 *
+		 * The file type can change if the application's pre- and post-
+		 * processing needs change.  For example, an application that
+		 * created a hash subdatabase in a database that was previously
+		 * all btree.
+		 *
+		 * !!!
+		 * We do not check to see if the pgcookie information changed,
+		 * or update it if it is.
+		 */
+		if ((dbmfp->clear_len != DB_CLEARLEN_NOTSET &&
+		    mfp->clear_len != DB_CLEARLEN_NOTSET &&
+		    dbmfp->clear_len != mfp->clear_len) ||
+		    (pagesize != 0 && pagesize != mfp->stat.st_pagesize) ||
+		    (dbmfp->lsn_offset != DB_LSN_OFF_NOTSET &&
+		    mfp->lsn_off != DB_LSN_OFF_NOTSET &&
+		    dbmfp->lsn_offset != mfp->lsn_off)) {
+			__db_errx(env,
+		    "%s: clear length, page size or LSN location changed",
+			    path);
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+			ret = EINVAL;
+			goto err;
+		}
+	}
+
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+	if (alloc_mfp != NULL) {
+		MUTEX_LOCK(env, alloc_mfp->mutex);
+		if ((ret = __memp_mf_discard(dbmp, alloc_mfp)) != 0)
+			goto err;
+	}
+
+	if (mfp == NULL) {
+		/*
+		 * If we didn't find the file and this is an in-memory file,
+		 * then the create flag should be set.
+		 */
+		if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE) &&
+		    !LF_ISSET(DB_CREATE)) {
+			ret = ENOENT;
+			goto err;
+		}
+
+alloc:		/*
+		 * Get the file ID if we weren't given one.  Generated file
+		 * ID's don't use timestamps, otherwise there'd be no
+		 * chance of any other process joining the party.
+		 */
+		if (path != NULL &&
+		     !FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE) &&
+		     !F_ISSET(dbmfp, MP_FILEID_SET) && (ret =
+			    __os_fileid(env, rpath, 0, dbmfp->fileid)) != 0)
+				goto err;
+
+		if ((ret = __memp_mpf_alloc(dbmp,
+		     dbmfp, path, pagesize, flags, &alloc_mfp)) != 0)
+			goto err;
+
+		/*
+		 * If the user specifies DB_MPOOL_LAST or DB_MPOOL_NEW on a
+		 * page get, we have to increment the last page in the file.
+		 * Figure it out and save it away.
+		 *
+		 * Note correction: page numbers are zero-based, not 1-based.
+		 */
+		DB_ASSERT(env, pagesize != 0);
+		last_pgno = (db_pgno_t)(mbytes * (MEGABYTE / pagesize));
+		last_pgno += (db_pgno_t)(bytes / pagesize);
+		if (last_pgno != 0)
+			--last_pgno;
+
+		alloc_mfp->last_flushed_pgno = alloc_mfp->orig_last_pgno =
+		    alloc_mfp->last_pgno = last_pgno;
+
+		alloc_mfp->bucket = bucket;
+
+		/* Go back and see if someone else has opened the file. */
+		if (path != NULL)
+			goto check;
+
+		mfp = alloc_mfp;
+		/* This is a temp, noone else can see it, put it at the end. */
+		MUTEX_LOCK(env, hp->mtx_hash);
+		SH_TAILQ_INSERT_TAIL(&hp->hash_bucket, mfp, q);
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+have_mfp:
+	/*
+	 * We need to verify that all handles open a file either durable or not
+	 * durable.  This needs to be cross process and cross sub-databases, so
+	 * mpool is the place to do it.
+	 */
+	if (!LF_ISSET(DB_DURABLE_UNKNOWN | DB_RDONLY)) {
+		if (F_ISSET(mfp, MP_DURABLE_UNKNOWN)) {
+			if (LF_ISSET(DB_TXN_NOT_DURABLE))
+				F_SET(mfp, MP_NOT_DURABLE);
+			F_CLR(mfp, MP_DURABLE_UNKNOWN);
+		} else if (!LF_ISSET(DB_TXN_NOT_DURABLE) !=
+		    !F_ISSET(mfp, MP_NOT_DURABLE)) {
+			__db_errx(env,
+	     "Cannot open DURABLE and NOT DURABLE handles in the same file");
+			ret = EINVAL;
+			goto err;
+		}
+	}
+
+	if (LF_ISSET(DB_MULTIVERSION)) {
+		++mfp->multiversion;
+		F_SET(dbmfp, MP_MULTIVERSION);
+	}
+
+	/*
+	 * All paths to here have initialized the mfp variable to reference
+	 * the selected (or allocated) MPOOLFILE.
+	 */
+	dbmfp->mfp = mfp;
+
+	/*
+	 * Check to see if we can mmap the file.  If a file:
+	 *	+ isn't temporary
+	 *	+ is read-only
+	 *	+ doesn't require any pgin/pgout support
+	 *	+ the DB_NOMMAP flag wasn't set (in either the file open or
+	 *	  the environment in which it was opened)
+	 *	+ and is less than mp_mmapsize bytes in size
+	 *
+	 * we can mmap it instead of reading/writing buffers.  Don't do error
+	 * checking based on the mmap call failure.  We want to do normal I/O
+	 * on the file if the reason we failed was because the file was on an
+	 * NFS mounted partition, and we can fail in buffer I/O just as easily
+	 * as here.
+	 *
+	 * We'd like to test to see if the file is too big to mmap.  Since we
+	 * don't know what size or type off_t's or size_t's are, or the largest
+	 * unsigned integral type is, or what random insanity the local C
+	 * compiler will perpetrate, doing the comparison in a portable way is
+	 * flatly impossible.  Hope that mmap fails if the file is too large.
+	 */
+#define	DB_MAXMMAPSIZE	(10 * 1024 * 1024)	/* 10 MB. */
+	if (F_ISSET(mfp, MP_CAN_MMAP)) {
+		maxmap = dbenv->mp_mmapsize == 0 ?
+		    DB_MAXMMAPSIZE : dbenv->mp_mmapsize;
+		if (path == NULL ||
+		    FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE))
+			F_CLR(mfp, MP_CAN_MMAP);
+		else if (!F_ISSET(dbmfp, MP_READONLY))
+			F_CLR(mfp, MP_CAN_MMAP);
+		else if (dbmfp->ftype != 0)
+			F_CLR(mfp, MP_CAN_MMAP);
+		else if (LF_ISSET(DB_NOMMAP) || F_ISSET(dbenv, DB_ENV_NOMMAP))
+			F_CLR(mfp, MP_CAN_MMAP);
+		else {
+			MPOOL_SYSTEM_LOCK(env);
+			maxmap = mp->mp_mmapsize == 0 ?
+			    DB_MAXMMAPSIZE : mp->mp_mmapsize;
+			MPOOL_SYSTEM_UNLOCK(env);
+			if (mbytes > maxmap / MEGABYTE ||
+			    (mbytes == maxmap / MEGABYTE &&
+			    bytes >= maxmap % MEGABYTE))
+				F_CLR(mfp, MP_CAN_MMAP);
+		}
+
+		dbmfp->addr = NULL;
+		if (F_ISSET(mfp, MP_CAN_MMAP)) {
+			dbmfp->len = (size_t)mbytes * MEGABYTE + bytes;
+			if (__os_mapfile(env, rpath,
+			    dbmfp->fhp, dbmfp->len, 1, &dbmfp->addr) != 0) {
+				dbmfp->addr = NULL;
+				F_CLR(mfp, MP_CAN_MMAP);
+			}
+		}
+	}
+
+	F_SET(dbmfp, MP_OPEN_CALLED);
+
+	/*
+	 * Share the underlying file descriptor if that's possible.
+	 *
+	 * Add the file to the process' list of DB_MPOOLFILEs.
+	 */
+	MUTEX_LOCK(env, dbmp->mutex);
+
+	if (dbmfp->fhp != NULL)
+		TAILQ_FOREACH(tmp_dbmfp, &dbmp->dbmfq, q)
+			if (dbmfp->mfp == tmp_dbmfp->mfp &&
+			    (F_ISSET(dbmfp, MP_READONLY) ||
+			    !F_ISSET(tmp_dbmfp, MP_READONLY))) {
+				(void)__mutex_free(env, &dbmfp->fhp->mtx_fh);
+				(void)__os_closehandle(env, dbmfp->fhp);
+				++tmp_dbmfp->fhp->ref;
+				dbmfp->fhp = tmp_dbmfp->fhp;
+				break;
+			}
+
+	TAILQ_INSERT_TAIL(&dbmp->dbmfq, dbmfp, q);
+
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	if (0) {
+err:		if (refinc) {
+			/*
+			 * If mpf_cnt goes to zero here and unlink_on_close is
+			 * set, then we missed the last close, but there was an
+			 * error trying to open the file, so we probably cannot
+			 * unlink it anyway.
+			 */
+			MUTEX_LOCK(env, mfp->mutex);
+			--mfp->mpf_cnt;
+			MUTEX_UNLOCK(env, mfp->mutex);
+		}
+
+	}
+	if (rpath != NULL)
+		__os_free(env, rpath);
+	return (ret);
+}
+
+/*
+ * __memp_mpf_find --
+ *	Search a hash bucket for a MPOOLFILE.
+ */
+static int
+__memp_mpf_find(env, dbmfp, hp, path, flags, mfpp)
+	ENV *env;
+	DB_MPOOLFILE *dbmfp;
+	DB_MPOOL_HASH *hp;
+	const char *path;
+	u_int32_t flags;
+	MPOOLFILE **mfpp;
+{
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+
+	dbmp = env->mp_handle;
+
+	SH_TAILQ_FOREACH(mfp, &hp->hash_bucket, q, __mpoolfile) {
+		/* Skip dead files and temporary files. */
+		if (mfp->deadfile || F_ISSET(mfp, MP_TEMP))
+			continue;
+
+		/*
+		 * Any remaining DB_MPOOL_NOFILE databases are in-memory
+		 * named databases and need only match other in-memory
+		 * databases with the same name.
+		 */
+		if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE)) {
+			if (!mfp->no_backing_file)
+				continue;
+
+			if (strcmp(path, R_ADDR(dbmp->reginfo, mfp->path_off)))
+				continue;
+
+			/*
+			 * We matched an in-memory file; grab the fileid if
+			 * it is set in the region, but not in the dbmfp.
+			 */
+			if (!F_ISSET(dbmfp, MP_FILEID_SET))
+				(void)__memp_set_fileid(dbmfp,
+				    R_ADDR(dbmp->reginfo, mfp->fileid_off));
+		} else
+			if (memcmp(dbmfp->fileid, R_ADDR(dbmp->reginfo,
+			    mfp->fileid_off), DB_FILE_ID_LEN) != 0)
+				continue;
+
+		/*
+		 * If the file is being truncated, remove it from the system
+		 * and create a new entry.
+		 *
+		 * !!!
+		 * We should be able to set mfp to NULL and break out of the
+		 * loop, but I like the idea of checking all the entries.
+		 */
+		if (LF_ISSET(DB_TRUNCATE)) {
+			MUTEX_LOCK(env, mfp->mutex);
+			mfp->deadfile = 1;
+			MUTEX_UNLOCK(env, mfp->mutex);
+			continue;
+		}
+
+		/*
+		 * Check to see if this file has died while we waited.
+		 *
+		 * We normally don't lock the deadfile field when we read it as
+		 * we only care if the field is zero or non-zero.  We do lock
+		 * on read when searching for a matching MPOOLFILE so that two
+		 * threads of control don't race between setting the deadfile
+		 * bit and incrementing the reference count, that is, a thread
+		 * of control decrementing the reference count and then setting
+		 * deadfile because the reference count is 0 blocks us finding
+		 * the file without knowing it's about to be marked dead.
+		 */
+		MUTEX_LOCK(env, mfp->mutex);
+		if (mfp->deadfile) {
+			MUTEX_UNLOCK(env, mfp->mutex);
+			continue;
+		}
+		++mfp->mpf_cnt;
+		MUTEX_UNLOCK(env, mfp->mutex);
+
+		/* Initialize any fields that are not yet set. */
+		if (dbmfp->ftype != 0)
+			mfp->ftype = dbmfp->ftype;
+		if (dbmfp->clear_len != DB_CLEARLEN_NOTSET)
+			mfp->clear_len = dbmfp->clear_len;
+		if (dbmfp->lsn_offset != -1)
+			mfp->lsn_off = dbmfp->lsn_offset;
+
+		break;
+	}
+
+	*mfpp = mfp;
+	return (0);
+}
+
+static int
+__memp_mpf_alloc(dbmp, dbmfp, path, pagesize, flags, retmfp)
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	const char *path;
+	u_int32_t pagesize;
+	u_int32_t flags;
+	MPOOLFILE **retmfp;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+	int ret;
+	void *p;
+
+	env = dbmp->env;
+	ret = 0;
+	/* Allocate and initialize a new MPOOLFILE. */
+	if ((ret = __memp_alloc(dbmp,
+	     dbmp->reginfo, NULL, sizeof(MPOOLFILE), NULL, &mfp)) != 0)
+		goto err;
+	memset(mfp, 0, sizeof(MPOOLFILE));
+	mfp->mpf_cnt = 1;
+	mfp->ftype = dbmfp->ftype;
+	mfp->stat.st_pagesize = pagesize;
+	mfp->lsn_off = dbmfp->lsn_offset;
+	mfp->clear_len = dbmfp->clear_len;
+	mfp->priority = dbmfp->priority;
+	if (dbmfp->gbytes != 0 || dbmfp->bytes != 0) {
+		mfp->maxpgno = (db_pgno_t)
+		    (dbmfp->gbytes * (GIGABYTE / mfp->stat.st_pagesize));
+		mfp->maxpgno += (db_pgno_t)
+		    ((dbmfp->bytes + mfp->stat.st_pagesize - 1) /
+		    mfp->stat.st_pagesize);
+	}
+	if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE))
+		mfp->no_backing_file = 1;
+	if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_UNLINK))
+		mfp->unlink_on_close = 1;
+
+	if (LF_ISSET(DB_DURABLE_UNKNOWN | DB_RDONLY))
+		F_SET(mfp, MP_DURABLE_UNKNOWN);
+	if (LF_ISSET(DB_DIRECT))
+		F_SET(mfp, MP_DIRECT);
+	if (LF_ISSET(DB_EXTENT))
+		F_SET(mfp, MP_EXTENT);
+	if (LF_ISSET(DB_TXN_NOT_DURABLE))
+		F_SET(mfp, MP_NOT_DURABLE);
+	F_SET(mfp, MP_CAN_MMAP);
+
+	/*
+	 * An in-memory database with no name is a temp file.  Named
+	 * in-memory databases get an artificially  bumped reference
+	 * count so they don't disappear on close; they need a remove
+	 * to make them disappear.
+	 */
+	if (path == NULL)
+		F_SET(mfp, MP_TEMP);
+	else if (FLD_ISSET(dbmfp->config_flags, DB_MPOOL_NOFILE))
+		mfp->mpf_cnt++;
+
+	/* Copy the file identification string into shared memory. */
+	if (F_ISSET(dbmfp, MP_FILEID_SET)) {
+		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+		    NULL, DB_FILE_ID_LEN, &mfp->fileid_off, &p)) != 0)
+			goto err;
+		memcpy(p, dbmfp->fileid, DB_FILE_ID_LEN);
+	}
+
+	/* Copy the file path into shared memory. */
+	if (path != NULL) {
+		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+		    NULL, strlen(path) + 1, &mfp->path_off, &p)) != 0)
+			goto err;
+		memcpy(p, path, strlen(path) + 1);
+	}
+
+	/* Copy the page cookie into shared memory. */
+	if (dbmfp->pgcookie == NULL || dbmfp->pgcookie->size == 0) {
+		mfp->pgcookie_len = 0;
+		mfp->pgcookie_off = 0;
+	} else {
+		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+		    NULL, dbmfp->pgcookie->size,
+		    &mfp->pgcookie_off, &p)) != 0)
+			goto err;
+		memcpy(p,
+		     dbmfp->pgcookie->data, dbmfp->pgcookie->size);
+		mfp->pgcookie_len = dbmfp->pgcookie->size;
+	}
+
+	if ((ret = __mutex_alloc(env,
+	    MTX_MPOOLFILE_HANDLE, 0, &mfp->mutex)) != 0)
+		goto err;
+	*retmfp = mfp;
+
+err:	return (ret);
+}
+
+/*
+ * memp_fclose_pp --
+ *	DB_MPOOLFILE->close pre/post processing.
+ *
+ * PUBLIC: int __memp_fclose_pp __P((DB_MPOOLFILE *, u_int32_t));
+ */
+int
+__memp_fclose_pp(dbmfp, flags)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t flags;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbmfp->env;
+
+	/*
+	 * Validate arguments, but as a handle destructor, we can't fail.
+	 */
+	if (flags != 0)
+		(void)__db_ferr(env, "DB_MPOOLFILE->close", 0);
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_fclose(dbmfp, 0)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_fclose --
+ *	DB_MPOOLFILE->close.
+ *
+ * PUBLIC: int __memp_fclose __P((DB_MPOOLFILE *, u_int32_t));
+ */
+int
+__memp_fclose(dbmfp, flags)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOLFILE *mfp;
+	char *rpath;
+	u_int32_t ref;
+	int deleted, ret, t_ret;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	ret = 0;
+
+	/*
+	 * Remove the DB_MPOOLFILE from the process' list.
+	 *
+	 * It's possible the underlying mpool cache may never have been created.
+	 * In that case, all we have is a structure, discard it.
+	 *
+	 * It's possible the DB_MPOOLFILE was never added to the DB_MPOOLFILE
+	 * file list, check the MP_OPEN_CALLED flag to be sure.
+	 */
+	if (dbmp == NULL)
+		goto done;
+
+	MUTEX_LOCK(env, dbmp->mutex);
+
+	DB_ASSERT(env, dbmfp->ref >= 1);
+	if ((ref = --dbmfp->ref) == 0 && F_ISSET(dbmfp, MP_OPEN_CALLED))
+		TAILQ_REMOVE(&dbmp->dbmfq, dbmfp, q);
+
+	/*
+	 * Decrement the file descriptor's ref count -- if we're the last ref,
+	 * we'll discard the file descriptor.
+	 */
+	if (ref == 0 && dbmfp->fhp != NULL && --dbmfp->fhp->ref > 0)
+		dbmfp->fhp = NULL;
+	MUTEX_UNLOCK(env, dbmp->mutex);
+	if (ref != 0)
+		return (0);
+
+	/* Complain if pinned blocks never returned. */
+	if (dbmfp->pinref != 0) {
+		__db_errx(env, "%s: close: %lu blocks left pinned",
+		    __memp_fn(dbmfp), (u_long)dbmfp->pinref);
+		ret = __env_panic(env, DB_RUNRECOVERY);
+	}
+
+	/* Discard any mmap information. */
+	if (dbmfp->addr != NULL &&
+	    (ret = __os_unmapfile(env, dbmfp->addr, dbmfp->len)) != 0)
+		__db_err(env, ret, "%s", __memp_fn(dbmfp));
+
+	/*
+	 * Close the file and discard the descriptor structure; temporary
+	 * files may not yet have been created.
+	 */
+	if (dbmfp->fhp != NULL) {
+		if ((t_ret =
+		    __mutex_free(env, &dbmfp->fhp->mtx_fh)) != 0 && ret == 0)
+			ret = t_ret;
+		if ((t_ret = __os_closehandle(env, dbmfp->fhp)) != 0) {
+			__db_err(env, t_ret, "%s", __memp_fn(dbmfp));
+			if (ret == 0)
+				ret = t_ret;
+		}
+		dbmfp->fhp = NULL;
+	}
+
+	/*
+	 * Discard our reference on the underlying MPOOLFILE, and close it
+	 * if it's no longer useful to anyone.  It possible the open of the
+	 * file never happened or wasn't successful, in which case, mpf will
+	 * be NULL and MP_OPEN_CALLED will not be set.
+	 */
+	mfp = dbmfp->mfp;
+	DB_ASSERT(env,
+	    (F_ISSET(dbmfp, MP_OPEN_CALLED) && mfp != NULL) ||
+	    (!F_ISSET(dbmfp, MP_OPEN_CALLED) && mfp == NULL));
+	if (!F_ISSET(dbmfp, MP_OPEN_CALLED))
+		goto done;
+
+	/*
+	 * If it's a temp file, all outstanding references belong to unflushed
+	 * buffers.  (A temp file can only be referenced by one DB_MPOOLFILE).
+	 * We don't care about preserving any of those buffers, so mark the
+	 * MPOOLFILE as dead so that even the dirty ones just get discarded
+	 * when we try to flush them.
+	 */
+	deleted = 0;
+	if (!LF_ISSET(DB_MPOOL_NOLOCK))
+		MUTEX_LOCK(env, mfp->mutex);
+	if (F_ISSET(dbmfp, MP_MULTIVERSION))
+		--mfp->multiversion;
+	if (--mfp->mpf_cnt == 0 || LF_ISSET(DB_MPOOL_DISCARD)) {
+		if (LF_ISSET(DB_MPOOL_DISCARD) ||
+		    F_ISSET(mfp, MP_TEMP) || mfp->unlink_on_close) {
+			mfp->deadfile = 1;
+		}
+		if (mfp->unlink_on_close) {
+			if ((t_ret = __db_appname(dbmp->env, DB_APP_DATA,
+			    R_ADDR(dbmp->reginfo, mfp->path_off), NULL,
+			    &rpath)) != 0 && ret == 0)
+				ret = t_ret;
+			if (t_ret == 0) {
+				if ((t_ret = __os_unlink(
+				    dbmp->env, rpath, 0)) != 0 && ret == 0)
+					ret = t_ret;
+				__os_free(env, rpath);
+			}
+		}
+		if (mfp->mpf_cnt == 0) {
+			F_CLR(mfp, MP_NOT_DURABLE);
+			F_SET(mfp, MP_DURABLE_UNKNOWN);
+		}
+		if (mfp->block_cnt == 0) {
+			/*
+			 * We should never discard this mp file if our caller
+			 * is holding the lock on it.  See comment in
+			 * __memp_sync_file.
+			 */
+			DB_ASSERT(env, !LF_ISSET(DB_MPOOL_NOLOCK));
+			if ((t_ret =
+			    __memp_mf_discard(dbmp, mfp)) != 0 && ret == 0)
+				ret = t_ret;
+			deleted = 1;
+		}
+	}
+	if (!deleted && !LF_ISSET(DB_MPOOL_NOLOCK))
+		MUTEX_UNLOCK(env, mfp->mutex);
+
+done:	/* Discard the DB_MPOOLFILE structure. */
+	if (dbmfp->pgcookie != NULL) {
+		__os_free(env, dbmfp->pgcookie->data);
+		__os_free(env, dbmfp->pgcookie);
+	}
+	__os_free(env, dbmfp);
+
+	return (ret);
+}
+
+/*
+ * __memp_mf_discard --
+ *	Discard an MPOOLFILE.
+ *
+ * PUBLIC: int __memp_mf_discard __P((DB_MPOOL *, MPOOLFILE *));
+ */
+int
+__memp_mf_discard(dbmp, mfp)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+{
+	DB_MPOOL_HASH *hp;
+	ENV *env;
+#ifdef HAVE_STATISTICS
+	DB_MPOOL_STAT *sp;
+#endif
+	MPOOL *mp;
+	int need_sync, ret, t_ret;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+	hp += mfp->bucket;
+	ret = 0;
+
+	/*
+	 * Expects caller to be holding the MPOOLFILE mutex.
+	 *
+	 * When discarding a file, we have to flush writes from it to disk.
+	 * The scenario is that dirty buffers from this file need to be
+	 * flushed to satisfy a future checkpoint, but when the checkpoint
+	 * calls mpool sync, the sync code won't know anything about them.
+	 * Ignore files not written, discarded, or only temporary.
+	 */
+	need_sync =
+	   mfp->file_written && !mfp->deadfile && !F_ISSET(mfp, MP_TEMP);
+
+	/*
+	 * We have to release the MPOOLFILE mutex before acquiring the region
+	 * mutex so we don't deadlock.  Make sure nobody ever looks at this
+	 * structure again.
+	 */
+	mfp->deadfile = 1;
+
+	/* Discard the mutex we're holding and return it too the pool. */
+	MUTEX_UNLOCK(env, mfp->mutex);
+	if ((t_ret = __mutex_free(env, &mfp->mutex)) != 0 && ret == 0)
+		ret = t_ret;
+
+	/* Lock the bucket and delete from the list of MPOOLFILEs. */
+	MUTEX_LOCK(env, hp->mtx_hash);
+	SH_TAILQ_REMOVE(&hp->hash_bucket, mfp, q, __mpoolfile);
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+
+	/* Lock the region and collect stats and free the space. */
+	MPOOL_SYSTEM_LOCK(env);
+	if (need_sync &&
+	    (t_ret = __memp_mf_sync(dbmp, mfp, 0)) != 0 && ret == 0)
+		ret = t_ret;
+
+#ifdef HAVE_STATISTICS
+	/* Copy the statistics into the region. */
+	sp = &mp->stat;
+	sp->st_cache_hit += mfp->stat.st_cache_hit;
+	sp->st_cache_miss += mfp->stat.st_cache_miss;
+	sp->st_map += mfp->stat.st_map;
+	sp->st_page_create += mfp->stat.st_page_create;
+	sp->st_page_in += mfp->stat.st_page_in;
+	sp->st_page_out += mfp->stat.st_page_out;
+#endif
+
+	/* Free the space. */
+	if (mfp->path_off != 0)
+		__memp_free(&dbmp->reginfo[0],
+		    R_ADDR(dbmp->reginfo, mfp->path_off));
+	if (mfp->fileid_off != 0)
+		__memp_free(&dbmp->reginfo[0],
+		    R_ADDR(dbmp->reginfo, mfp->fileid_off));
+	if (mfp->pgcookie_off != 0)
+		__memp_free(&dbmp->reginfo[0],
+		    R_ADDR(dbmp->reginfo, mfp->pgcookie_off));
+	__memp_free(&dbmp->reginfo[0], mfp);
+
+	MPOOL_SYSTEM_UNLOCK(env);
+
+	return (ret);
+}
+
+/*
+ * __memp_inmemlist --
+ *	Return a list of the named in-memory databases.
+ *
+ * PUBLIC: int __memp_inmemlist __P((ENV *, char ***, int *));
+ */
+int
+__memp_inmemlist(env, namesp, cntp)
+	ENV *env;
+	char ***namesp;
+	int *cntp;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *mp;
+	MPOOLFILE *mfp;
+	int arraysz, cnt, i, ret;
+	char **names;
+
+	names = NULL;
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+
+	arraysz = cnt = 0;
+	for (i = 0; i < MPOOL_FILE_BUCKETS; i++, hp++) {
+		MUTEX_LOCK(env, hp->mtx_hash);
+		SH_TAILQ_FOREACH(mfp, &hp->hash_bucket, q, __mpoolfile) {
+			/* Skip dead files and temporary files. */
+			if (mfp->deadfile || F_ISSET(mfp, MP_TEMP))
+				continue;
+
+			/* Skip entries that allow files. */
+			if (!mfp->no_backing_file)
+				continue;
+
+			/* We found one. */
+			if (cnt >= arraysz) {
+				arraysz += 100;
+				if ((ret = __os_realloc(env,
+				    (u_int)arraysz * sizeof(names[0]),
+				    &names)) != 0)
+					goto nomem;
+			}
+			if ((ret = __os_strdup(env,
+			    R_ADDR(dbmp->reginfo, mfp->path_off),
+			    &names[cnt])) != 0)
+				goto nomem;
+
+			cnt++;
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+	*namesp = names;
+	*cntp = cnt;
+	return (0);
+
+nomem:	MUTEX_UNLOCK(env, hp->mtx_hash);
+	if (names != NULL) {
+		while (--cnt >= 0)
+			__os_free(env, names[cnt]);
+		__os_free(env, names);
+	}
+
+	/* Make sure we don't return any garbage. */
+	*cntp = 0;
+	*namesp = NULL;
+	return (ret);
+}
diff --git a/mp/mp_fput.c b/mp/mp_fput.c
new file mode 100644
index 0000000..0f8598c
--- /dev/null
+++ b/mp/mp_fput.c
@@ -0,0 +1,367 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+
+static int __memp_reset_lru __P((ENV *, REGINFO *));
+
+/*
+ * __memp_fput_pp --
+ *	DB_MPOOLFILE->put pre/post processing.
+ *
+ * PUBLIC: int __memp_fput_pp
+ * PUBLIC:     __P((DB_MPOOLFILE *, void *, DB_CACHE_PRIORITY, u_int32_t));
+ */
+int
+__memp_fput_pp(dbmfp, pgaddr, priority, flags)
+	DB_MPOOLFILE *dbmfp;
+	void *pgaddr;
+	DB_CACHE_PRIORITY priority;
+	u_int32_t flags;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret, t_ret;
+
+	env = dbmfp->env;
+
+	if (flags != 0)
+		return (__db_ferr(env, "DB_MPOOLFILE->put", 0));
+
+	MPF_ILLEGAL_BEFORE_OPEN(dbmfp, "DB_MPOOLFILE->put");
+
+	ENV_ENTER(env, ip);
+
+	ret = __memp_fput(dbmfp, ip, pgaddr, priority);
+	if (IS_ENV_REPLICATED(env) &&
+	    (t_ret = __op_rep_exit(env)) != 0 && ret == 0)
+		ret = t_ret;
+
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_fput --
+ *	DB_MPOOLFILE->put.
+ *
+ * PUBLIC: int __memp_fput __P((DB_MPOOLFILE *,
+ * PUBLIC:      DB_THREAD_INFO *, void *, DB_CACHE_PRIORITY));
+ */
+int
+__memp_fput(dbmfp, ip, pgaddr, priority)
+	DB_MPOOLFILE *dbmfp;
+	DB_THREAD_INFO *ip;
+	void *pgaddr;
+	DB_CACHE_PRIORITY priority;
+{
+	BH *bhp;
+	DB_ENV *dbenv;
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	ENV *env;
+	MPOOL *c_mp;
+	MPOOLFILE *mfp;
+	PIN_LIST *list, *lp;
+	REGINFO *infop, *reginfo;
+	roff_t b_ref;
+	int region;
+	int adjust, pfactor, ret, t_ret;
+	char buf[DB_THREADID_STRLEN];
+
+	env = dbmfp->env;
+	dbenv = env->dbenv;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+	bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));
+	ret = 0;
+
+	/*
+	 * If this is marked dummy, we are using it to unpin a buffer for
+	 * another thread.
+	 */
+	if (F_ISSET(dbmfp, MP_DUMMY))
+		goto unpin;
+
+	/*
+	 * If we're mapping the file, there's nothing to do.  Because we can
+	 * stop mapping the file at any time, we have to check on each buffer
+	 * to see if the address we gave the application was part of the map
+	 * region.
+	 */
+	if (dbmfp->addr != NULL && pgaddr >= dbmfp->addr &&
+	    (u_int8_t *)pgaddr <= (u_int8_t *)dbmfp->addr + dbmfp->len)
+		return (0);
+
+#ifdef DIAGNOSTIC
+	/*
+	 * Decrement the per-file pinned buffer count (mapped pages aren't
+	 * counted).
+	 */
+	MPOOL_SYSTEM_LOCK(env);
+	if (dbmfp->pinref == 0) {
+		MPOOL_SYSTEM_UNLOCK(env);
+		__db_errx(env,
+		    "%s: more pages returned than retrieved", __memp_fn(dbmfp));
+		return (__env_panic(env, EACCES));
+	}
+	--dbmfp->pinref;
+	MPOOL_SYSTEM_UNLOCK(env);
+#endif
+
+unpin:
+	infop = &dbmp->reginfo[bhp->region];
+	c_mp = infop->primary;
+	hp = R_ADDR(infop, c_mp->htab);
+	hp = &hp[bhp->bucket];
+
+	/*
+	 * Check for a reference count going to zero.  This can happen if the
+	 * application returns a page twice.
+	 */
+	if (atomic_read(&bhp->ref) == 0) {
+		__db_errx(env, "%s: page %lu: unpinned page returned",
+		    __memp_fn(dbmfp), (u_long)bhp->pgno);
+		DB_ASSERT(env, atomic_read(&bhp->ref) != 0);
+		return (__env_panic(env, EACCES));
+	}
+
+	/* Note the activity so allocation won't decide to quit. */
+	++c_mp->put_counter;
+
+	if (ip != NULL) {
+		reginfo = env->reginfo;
+		list = R_ADDR(reginfo, ip->dbth_pinlist);
+		region = (int)(infop - dbmp->reginfo);
+		b_ref = R_OFFSET(infop, bhp);
+		for (lp = list; lp < &list[ip->dbth_pinmax]; lp++)
+			if (lp->b_ref == b_ref && lp->region == region)
+				break;
+
+		if (lp == &list[ip->dbth_pinmax]) {
+			__db_errx(env,
+		    "__memp_fput: pinned buffer not found for thread %s",
+			    dbenv->thread_id_string(dbenv,
+			    ip->dbth_pid, ip->dbth_tid, buf));
+			return (__env_panic(env, EINVAL));
+		}
+
+		lp->b_ref = INVALID_ROFF;
+		ip->dbth_pincount--;
+	}
+
+	/*
+	 * Mark the file dirty.
+	 */
+	if (F_ISSET(bhp, BH_EXCLUSIVE) && F_ISSET(bhp, BH_DIRTY)) {
+		DB_ASSERT(env, atomic_read(&hp->hash_page_dirty) > 0);
+		mfp->file_written = 1;
+	}
+
+	/*
+	 * If more than one reference to the page we're done.  Ignore the
+	 * discard flags (for now) and leave the buffer's priority alone.
+	 * We are doing this a little early as the remaining ref may or
+	 * may not be a write behind.  If it is we set the priority
+	 * here, if not it will get set again later.  We might race
+	 * and miss setting the priority which would leave it wrong
+	 * for a while.
+	 */
+	DB_ASSERT(env, atomic_read(&bhp->ref) != 0);
+	if (atomic_dec(env, &bhp->ref) > 1 || (atomic_read(&bhp->ref) == 1 &&
+	    !F_ISSET(bhp, BH_DIRTY))) {
+		/*
+		 * __memp_pgwrite only has a shared lock while it clears
+		 * the BH_DIRTY bit. If we only have a shared latch then
+		 * we can't touch the flags bits.
+		 */
+		if (F_ISSET(bhp, BH_EXCLUSIVE))
+			F_CLR(bhp, BH_EXCLUSIVE);
+		MUTEX_UNLOCK(env, bhp->mtx_buf);
+		return (0);
+	}
+
+	/* The buffer should not be accessed again. */
+	if (BH_REFCOUNT(bhp) == 0)
+		MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize, 0);
+
+	/* Update priority values. */
+	if (priority == DB_PRIORITY_VERY_LOW ||
+	    mfp->priority == MPOOL_PRI_VERY_LOW)
+		bhp->priority = 0;
+	else {
+		/*
+		 * We don't lock the LRU counter or the stat.st_pages field, if
+		 * we get garbage (which won't happen on a 32-bit machine), it
+		 * only means a buffer has the wrong priority.
+		 */
+		bhp->priority = c_mp->lru_count;
+
+		switch (priority) {
+		default:
+		case DB_PRIORITY_UNCHANGED:
+			pfactor = mfp->priority;
+			break;
+		case DB_PRIORITY_VERY_LOW:
+			pfactor = MPOOL_PRI_VERY_LOW;
+			break;
+		case DB_PRIORITY_LOW:
+			pfactor = MPOOL_PRI_LOW;
+			break;
+		case DB_PRIORITY_DEFAULT:
+			pfactor = MPOOL_PRI_DEFAULT;
+			break;
+		case DB_PRIORITY_HIGH:
+			pfactor = MPOOL_PRI_HIGH;
+			break;
+		case DB_PRIORITY_VERY_HIGH:
+			pfactor = MPOOL_PRI_VERY_HIGH;
+			break;
+		}
+
+		adjust = 0;
+		if (pfactor != 0)
+			adjust = (int)c_mp->stat.st_pages / pfactor;
+
+		if (F_ISSET(bhp, BH_DIRTY))
+			adjust += (int)c_mp->stat.st_pages / MPOOL_PRI_DIRTY;
+
+		if (adjust > 0) {
+			if (UINT32_MAX - bhp->priority >= (u_int32_t)adjust)
+				bhp->priority += adjust;
+		} else if (adjust < 0)
+			if (bhp->priority > (u_int32_t)-adjust)
+				bhp->priority += adjust;
+	}
+
+	/*
+	 * __memp_pgwrite only has a shared lock while it clears the
+	 * BH_DIRTY bit. If we only have a shared latch then we can't
+	 * touch the flags bits.
+	 */
+	if (F_ISSET(bhp, BH_EXCLUSIVE))
+		F_CLR(bhp, BH_EXCLUSIVE);
+	MUTEX_UNLOCK(env, bhp->mtx_buf);
+
+	/*
+	 * On every buffer put we update the buffer generation number and check
+	 * for wraparound.
+	 */
+	if (++c_mp->lru_count == UINT32_MAX)
+		if ((t_ret =
+		    __memp_reset_lru(env, dbmp->reginfo)) != 0 && ret == 0)
+			ret = t_ret;
+
+	return (ret);
+}
+
+/*
+ * __memp_reset_lru --
+ *	Reset the cache LRU counter.
+ */
+static int
+__memp_reset_lru(env, infop)
+	ENV *env;
+	REGINFO *infop;
+{
+	BH *bhp, *tbhp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *c_mp;
+	u_int32_t bucket, priority;
+
+	c_mp = infop->primary;
+	/*
+	 * Update the counter so all future allocations will start at the
+	 * bottom.
+	 */
+	c_mp->lru_count -= MPOOL_BASE_DECREMENT;
+
+	/* Adjust the priority of every buffer in the system. */
+	for (hp = R_ADDR(infop, c_mp->htab),
+	    bucket = 0; bucket < c_mp->htab_buckets; ++hp, ++bucket) {
+		/*
+		 * Skip empty buckets.
+		 *
+		 * We can check for empty buckets before locking as we
+		 * only care if the pointer is zero or non-zero.
+		 */
+		if (SH_TAILQ_FIRST(&hp->hash_bucket, __bh) == NULL) {
+			c_mp->lru_reset++;
+			continue;
+		}
+
+		MUTEX_LOCK(env, hp->mtx_hash);
+		c_mp->lru_reset++;
+		/*
+		 * We need to take a little care that the bucket does
+		 * not become unsorted.  This is highly unlikely but
+		 * possible.
+		 */
+		priority = 0;
+		SH_TAILQ_FOREACH(bhp, &hp->hash_bucket, hq, __bh) {
+			for (tbhp = bhp; tbhp != NULL;
+			    tbhp = SH_CHAIN_PREV(tbhp, vc, __bh)) {
+				if (tbhp->priority != UINT32_MAX &&
+				    tbhp->priority > MPOOL_BASE_DECREMENT) {
+					tbhp->priority -= MPOOL_BASE_DECREMENT;
+					if (tbhp->priority < priority)
+						tbhp->priority = priority;
+				}
+			}
+			priority = bhp->priority;
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+	c_mp->lru_reset = 0;
+
+	COMPQUIET(env, NULL);
+	return (0);
+}
+
+/*
+ * __memp_unpin_buffers --
+ *	Unpin buffers pinned by a thread.
+ *
+ * PUBLIC: int __memp_unpin_buffers __P((ENV *, DB_THREAD_INFO *));
+ */
+int
+__memp_unpin_buffers(env, ip)
+	ENV *env;
+	DB_THREAD_INFO *ip;
+{
+	BH *bhp;
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE dbmf;
+	PIN_LIST *list, *lp;
+	REGINFO *rinfop, *reginfo;
+	int ret;
+
+	memset(&dbmf, 0, sizeof(dbmf));
+	dbmf.env = env;
+	dbmf.flags = MP_DUMMY;
+	dbmp = env->mp_handle;
+	reginfo = env->reginfo;
+
+	list = R_ADDR(reginfo, ip->dbth_pinlist);
+	for (lp = list; lp < &list[ip->dbth_pinmax]; lp++) {
+		if (lp->b_ref == INVALID_ROFF)
+			continue;
+		rinfop = &dbmp->reginfo[lp->region];
+		bhp = R_ADDR(rinfop, lp->b_ref);
+		dbmf.mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+		if ((ret = __memp_fput(&dbmf, ip,
+		    (u_int8_t *)bhp + SSZA(BH, buf),
+		    DB_PRIORITY_UNCHANGED)) != 0)
+			return (ret);
+	}
+	return (0);
+}
diff --git a/mp/mp_fset.c b/mp/mp_fset.c
new file mode 100644
index 0000000..2869fc8
--- /dev/null
+++ b/mp/mp_fset.c
@@ -0,0 +1,165 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+/*
+ * __memp_dirty --
+ *	Upgrade a page from a read-only to a writeable pointer.
+ *
+ * PUBLIC: int __memp_dirty __P((DB_MPOOLFILE *, void *,
+ * PUBLIC:     DB_THREAD_INFO *, DB_TXN *, DB_CACHE_PRIORITY, u_int32_t));
+ */
+int
+__memp_dirty(dbmfp, addrp, ip, txn, priority, flags)
+	DB_MPOOLFILE *dbmfp;
+	void *addrp;
+	DB_THREAD_INFO *ip;
+	DB_TXN *txn;
+	DB_CACHE_PRIORITY priority;
+	u_int32_t flags;
+{
+	BH *bhp;
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	DB_TXN *ancestor;
+	ENV *env;
+	MPOOL *c_mp;
+#ifdef DIAG_MVCC
+	MPOOLFILE *mfp;
+#endif
+	REGINFO *infop;
+	int mvcc, ret;
+	db_pgno_t pgno;
+	void *pgaddr;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mvcc = dbmfp->mfp->multiversion;
+
+	/* Convert the page address to a buffer header. */
+	pgaddr = *(void **)addrp;
+	bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));
+	pgno = bhp->pgno;
+
+	/* If we have it exclusively then its already dirty. */
+	if (F_ISSET(bhp, BH_EXCLUSIVE)) {
+		DB_ASSERT(env, F_ISSET(bhp, BH_DIRTY));
+		return (0);
+	}
+
+	if (flags == 0)
+		flags = DB_MPOOL_DIRTY;
+	DB_ASSERT(env, flags == DB_MPOOL_DIRTY || flags == DB_MPOOL_EDIT);
+
+	if (F_ISSET(dbmfp, MP_READONLY)) {
+		__db_errx(env, "%s: dirty flag set for readonly file page",
+		    __memp_fn(dbmfp));
+		return (EACCES);
+	}
+
+	for (ancestor = txn;
+	    ancestor != NULL && ancestor->parent != NULL;
+	    ancestor = ancestor->parent)
+		;
+
+	if (mvcc && txn != NULL && flags == DB_MPOOL_DIRTY &&
+	    (!BH_OWNED_BY(env, bhp, ancestor) || SH_CHAIN_HASNEXT(bhp, vc))) {
+		atomic_inc(env, &bhp->ref);
+		*(void **)addrp = NULL;
+		if ((ret = __memp_fput(dbmfp, ip, pgaddr, priority)) != 0) {
+			__db_errx(env,
+			    "%s: error releasing a read-only page",
+			    __memp_fn(dbmfp));
+			atomic_dec(env, &bhp->ref);
+			return (ret);
+		}
+		if ((ret = __memp_fget(dbmfp,
+		    &pgno, ip, txn, flags, addrp)) != 0) {
+			if (ret != DB_LOCK_DEADLOCK)
+				__db_errx(env,
+				    "%s: error getting a page for writing",
+				    __memp_fn(dbmfp));
+			atomic_dec(env, &bhp->ref);
+			return (ret);
+		}
+		atomic_dec(env, &bhp->ref);
+
+		DB_ASSERT(env,
+		    flags == DB_MPOOL_DIRTY && *(void **)addrp != pgaddr);
+
+		pgaddr = *(void **)addrp;
+		bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));
+		DB_ASSERT(env, pgno == bhp->pgno);
+		return (0);
+	}
+
+	infop = &dbmp->reginfo[bhp->region];
+	c_mp = infop->primary;
+	hp = R_ADDR(infop, c_mp->htab);
+	hp = &hp[bhp->bucket];
+
+	/* Drop the shared latch and get an exclusive. We have the buf ref'ed.*/
+	MUTEX_UNLOCK(env, bhp->mtx_buf);
+	MUTEX_LOCK(env, bhp->mtx_buf);
+	DB_ASSERT(env, !F_ISSET(bhp, BH_EXCLUSIVE));
+	F_SET(bhp, BH_EXCLUSIVE);
+
+	/* Set/clear the page bits. */
+	if (!F_ISSET(bhp, BH_DIRTY)) {
+#ifdef DIAGNOSTIC
+		MUTEX_LOCK(env, hp->mtx_hash);
+#endif
+		atomic_inc(env, &hp->hash_page_dirty);
+		F_SET(bhp, BH_DIRTY);
+#ifdef DIAGNOSTIC
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+#endif
+	}
+
+#ifdef DIAG_MVCC
+	mfp = R_ADDR(env->mp_handle->reginfo, bhp->mf_offset);
+	MVCC_MPROTECT(bhp->buf, mfp->stat.st_pagesize, PROT_READ | PROT_WRITE);
+#endif
+	DB_ASSERT(env, !F_ISSET(bhp, BH_DIRTY) ||
+	    atomic_read(&hp->hash_page_dirty) != 0);
+	return (0);
+}
+
+/*
+ * __memp_shared --
+ *	Downgrade a page from exlusively held to shared.
+ *
+ * PUBLIC: int __memp_shared __P((DB_MPOOLFILE *, void *));
+ */
+int
+__memp_shared(dbmfp, pgaddr)
+	DB_MPOOLFILE *dbmfp;
+	void *pgaddr;
+{
+	BH *bhp;
+	ENV *env;
+
+	env = dbmfp->env;
+	/* Convert the page address to a buffer header. */
+	bhp = (BH *)((u_int8_t *)pgaddr - SSZA(BH, buf));
+
+	if (F_ISSET(bhp, BH_DIRTY))
+		dbmfp->mfp->file_written = 1;
+	DB_ASSERT(env, F_ISSET(bhp, BH_EXCLUSIVE));
+	F_CLR(bhp, BH_EXCLUSIVE);
+	MUTEX_UNLOCK(env, bhp->mtx_buf);
+	MUTEX_READLOCK(env, bhp->mtx_buf);
+
+	return (0);
+}
diff --git a/mp/mp_method.c b/mp/mp_method.c
new file mode 100644
index 0000000..c51a404
--- /dev/null
+++ b/mp/mp_method.c
@@ -0,0 +1,992 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/mp.h"
+#include "dbinc/db_page.h"
+#include "dbinc/hash.h"
+
+/*
+ * __memp_env_create --
+ *	Mpool specific creation of the DB_ENV structure.
+ *
+ * PUBLIC: int __memp_env_create __P((DB_ENV *));
+ */
+int
+__memp_env_create(dbenv)
+	DB_ENV *dbenv;
+{
+	/*
+	 * !!!
+	 * Our caller has not yet had the opportunity to reset the panic
+	 * state or turn off mutex locking, and so we can neither check
+	 * the panic state or acquire a mutex in the DB_ENV create path.
+	 *
+	 * We default to 32 8K pages.  We don't default to a flat 256K, because
+	 * some systems require significantly more memory to hold 32 pages than
+	 * others.  For example, HP-UX with POSIX pthreads needs 88 bytes for
+	 * a POSIX pthread mutex and almost 200 bytes per buffer header, while
+	 * Solaris needs 24 and 52 bytes for the same structures.  The minimum
+	 * number of hash buckets is 37.  These contain a mutex also.
+	 */
+	dbenv->mp_bytes = dbenv->mp_max_bytes =
+	    32 * ((8 * 1024) + sizeof(BH)) + 37 * sizeof(DB_MPOOL_HASH);
+	dbenv->mp_ncache = 1;
+
+	return (0);
+}
+
+/*
+ * __memp_env_destroy --
+ *	Mpool specific destruction of the DB_ENV structure.
+ *
+ * PUBLIC: void __memp_env_destroy __P((DB_ENV *));
+ */
+void
+__memp_env_destroy(dbenv)
+	DB_ENV *dbenv;
+{
+	COMPQUIET(dbenv, NULL);
+}
+
+/*
+ * __memp_get_cachesize --
+ *	{DB_ENV,DB}->get_cachesize.
+ *
+ * PUBLIC: int __memp_get_cachesize
+ * PUBLIC:         __P((DB_ENV *, u_int32_t *, u_int32_t *, int *));
+ */
+int
+__memp_get_cachesize(dbenv, gbytesp, bytesp, ncachep)
+	DB_ENV *dbenv;
+	u_int32_t *gbytesp, *bytesp;
+	int *ncachep;
+{
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_cachesize", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		/* Cannot be set after open, no lock required to read. */
+		mp = env->mp_handle->reginfo[0].primary;
+		if (gbytesp != NULL)
+			*gbytesp = mp->stat.st_gbytes;
+		if (bytesp != NULL)
+			*bytesp = mp->stat.st_bytes;
+		if (ncachep != NULL)
+			*ncachep = (int)mp->nreg;
+	} else {
+		if (gbytesp != NULL)
+			*gbytesp = dbenv->mp_gbytes;
+		if (bytesp != NULL)
+			*bytesp = dbenv->mp_bytes;
+		if (ncachep != NULL)
+			*ncachep = (int)dbenv->mp_ncache;
+	}
+	return (0);
+}
+
+/*
+ * __memp_set_cachesize --
+ *	{DB_ENV,DB}->set_cachesize.
+ *
+ * PUBLIC: int __memp_set_cachesize __P((DB_ENV *, u_int32_t, u_int32_t, int));
+ */
+int
+__memp_set_cachesize(dbenv, gbytes, bytes, arg_ncache)
+	DB_ENV *dbenv;
+	u_int32_t gbytes, bytes;
+	int arg_ncache;
+{
+	ENV *env;
+	u_int ncache;
+
+	env = dbenv->env;
+
+	/* Normalize the cache count. */
+	ncache = arg_ncache <= 0 ? 1 : (u_int)arg_ncache;
+
+	/*
+	 * You can only store 4GB-1 in an unsigned 32-bit value, so correct for
+	 * applications that specify 4GB cache sizes -- we know what they meant.
+	 */
+	if (sizeof(roff_t) == 4 && gbytes / ncache == 4 && bytes == 0) {
+		--gbytes;
+		bytes = GIGABYTE - 1;
+	} else {
+		gbytes += bytes / GIGABYTE;
+		bytes %= GIGABYTE;
+	}
+
+	/*
+	 * !!!
+	 * With 32-bit region offsets, individual cache regions must be smaller
+	 * than 4GB.  Also, cache sizes larger than 10TB would cause 32-bit
+	 * wrapping in the calculation of the number of hash buckets.  See
+	 * __memp_open for details.
+	 */
+	if (!F_ISSET(env, ENV_OPEN_CALLED)) {
+		if (sizeof(roff_t) <= 4 && gbytes / ncache >= 4) {
+			__db_errx(env,
+			    "individual cache size too large: maximum is 4GB");
+			return (EINVAL);
+		}
+		if (gbytes / ncache > 10000) {
+			__db_errx(env,
+			    "individual cache size too large: maximum is 10TB");
+			return (EINVAL);
+		}
+	}
+
+	/*
+	 * If the application requested less than 500Mb, increase the cachesize
+	 * by 25% and factor in the size of the hash buckets to account for our
+	 * overhead.  (I'm guessing caches over 500Mb are specifically sized,
+	 * that is, it's a large server and the application actually knows how
+	 * much memory is available.  We only document the 25% overhead number,
+	 * not the hash buckets, but I don't see a reason to confuse the issue,
+	 * it shouldn't matter to an application.)
+	 *
+	 * There is a minimum cache size, regardless.
+	 */
+	if (gbytes == 0) {
+		if (bytes < 500 * MEGABYTE)
+			bytes += (bytes / 4) + 37 * sizeof(DB_MPOOL_HASH);
+		if (bytes / ncache < DB_CACHESIZE_MIN)
+			bytes = ncache * DB_CACHESIZE_MIN;
+	}
+
+	if (F_ISSET(env, ENV_OPEN_CALLED))
+		return (__memp_resize(env->mp_handle, gbytes, bytes));
+
+	dbenv->mp_gbytes = gbytes;
+	dbenv->mp_bytes = bytes;
+	dbenv->mp_ncache = ncache;
+
+	return (0);
+}
+
+/*
+ * __memp_set_config --
+ *	Set the cache subsystem configuration.
+ *
+ * PUBLIC: int __memp_set_config __P((DB_ENV *, u_int32_t, int));
+ */
+int
+__memp_set_config(dbenv, which, on)
+	DB_ENV *dbenv;
+	u_int32_t which;
+	int on;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->memp_set_config", DB_INIT_MPOOL);
+
+	switch (which) {
+	case DB_MEMP_SUPPRESS_WRITE:
+	case DB_MEMP_SYNC_INTERRUPT:
+		if (MPOOL_ON(env)) {
+			dbmp = env->mp_handle;
+			mp = dbmp->reginfo[0].primary;
+			if (on)
+				FLD_SET(mp->config_flags, which);
+			else
+				FLD_CLR(mp->config_flags, which);
+		}
+		break;
+	default:
+		return (EINVAL);
+	}
+	return (0);
+}
+
+/*
+ * __memp_get_config --
+ *	Return the cache subsystem configuration.
+ *
+ * PUBLIC: int __memp_get_config __P((DB_ENV *, u_int32_t, int *));
+ */
+int
+__memp_get_config(dbenv, which, onp)
+	DB_ENV *dbenv;
+	u_int32_t which;
+	int *onp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "DB_ENV->memp_get_config", DB_INIT_MPOOL);
+
+	switch (which) {
+	case DB_MEMP_SUPPRESS_WRITE:
+	case DB_MEMP_SYNC_INTERRUPT:
+		if (MPOOL_ON(env)) {
+			dbmp = env->mp_handle;
+			mp = dbmp->reginfo[0].primary;
+			*onp = FLD_ISSET(mp->config_flags, which) ? 1 : 0;
+		} else
+			*onp = 0;
+		break;
+	default:
+		return (EINVAL);
+	}
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_get_mp_max_openfd __P((DB_ENV *, int *));
+ */
+int
+__memp_get_mp_max_openfd(dbenv, maxopenfdp)
+	DB_ENV *dbenv;
+	int *maxopenfdp;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_openfd", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		*maxopenfdp = mp->mp_maxopenfd;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else
+		*maxopenfdp = dbenv->mp_maxopenfd;
+	return (0);
+}
+
+/*
+ * __memp_set_mp_max_openfd --
+ *	Set the maximum number of open fd's when flushing the cache.
+ * PUBLIC: int __memp_set_mp_max_openfd __P((DB_ENV *, int));
+ */
+int
+__memp_set_mp_max_openfd(dbenv, maxopenfd)
+	DB_ENV *dbenv;
+	int maxopenfd;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->set_mp_max_openfd", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		mp->mp_maxopenfd = maxopenfd;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else
+		dbenv->mp_maxopenfd = maxopenfd;
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_get_mp_max_write __P((DB_ENV *, int *, db_timeout_t *));
+ */
+int
+__memp_get_mp_max_write(dbenv, maxwritep, maxwrite_sleepp)
+	DB_ENV *dbenv;
+	int *maxwritep;
+	db_timeout_t *maxwrite_sleepp;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_write", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		*maxwritep = mp->mp_maxwrite;
+		*maxwrite_sleepp = mp->mp_maxwrite_sleep;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else {
+		*maxwritep = dbenv->mp_maxwrite;
+		*maxwrite_sleepp = dbenv->mp_maxwrite_sleep;
+	}
+	return (0);
+}
+
+/*
+ * __memp_set_mp_max_write --
+ *	Set the maximum continuous I/O count.
+ *
+ * PUBLIC: int __memp_set_mp_max_write __P((DB_ENV *, int, db_timeout_t));
+ */
+int
+__memp_set_mp_max_write(dbenv, maxwrite, maxwrite_sleep)
+	DB_ENV *dbenv;
+	int maxwrite;
+	db_timeout_t maxwrite_sleep;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_write", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		mp->mp_maxwrite = maxwrite;
+		mp->mp_maxwrite_sleep = maxwrite_sleep;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else {
+		dbenv->mp_maxwrite = maxwrite;
+		dbenv->mp_maxwrite_sleep = maxwrite_sleep;
+	}
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_get_mp_mmapsize __P((DB_ENV *, size_t *));
+ */
+int
+__memp_get_mp_mmapsize(dbenv, mp_mmapsizep)
+	DB_ENV *dbenv;
+	size_t *mp_mmapsizep;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_mmapsize", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		*mp_mmapsizep = mp->mp_mmapsize;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else
+		*mp_mmapsizep = dbenv->mp_mmapsize;
+	return (0);
+}
+
+/*
+ * __memp_set_mp_mmapsize --
+ *	DB_ENV->set_mp_mmapsize.
+ *
+ * PUBLIC: int __memp_set_mp_mmapsize __P((DB_ENV *, size_t));
+ */
+int
+__memp_set_mp_mmapsize(dbenv, mp_mmapsize)
+	DB_ENV *dbenv;
+	size_t mp_mmapsize;
+{
+	DB_MPOOL *dbmp;
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	MPOOL *mp;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->set_mp_max_mmapsize", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		ENV_ENTER(env, ip);
+		MPOOL_SYSTEM_LOCK(env);
+		mp->mp_mmapsize = mp_mmapsize;
+		MPOOL_SYSTEM_UNLOCK(env);
+		ENV_LEAVE(env, ip);
+	} else
+		dbenv->mp_mmapsize = mp_mmapsize;
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_get_mp_pagesize __P((DB_ENV *, u_int32_t *));
+ */
+int
+__memp_get_mp_pagesize(dbenv, mp_pagesizep)
+	DB_ENV *dbenv;
+	u_int32_t *mp_pagesizep;
+{
+	ENV *env;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_pagesize", DB_INIT_MPOOL);
+
+	*mp_pagesizep = dbenv->mp_pagesize;
+	return (0);
+}
+
+/*
+ * __memp_set_mp_pagesize --
+ *	DB_ENV->set_mp_pagesize.
+ *
+ * PUBLIC: int __memp_set_mp_pagesize __P((DB_ENV *, u_int32_t));
+ */
+int
+__memp_set_mp_pagesize(dbenv, mp_pagesize)
+	DB_ENV *dbenv;
+	u_int32_t mp_pagesize;
+{
+	ENV *env;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_mmapsize", DB_INIT_MPOOL);
+	ENV_ILLEGAL_AFTER_OPEN(env, "DB_ENV->set_mp_pagesize");
+
+	dbenv->mp_pagesize = mp_pagesize;
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_get_mp_tablesize __P((DB_ENV *, u_int32_t *));
+ */
+int
+__memp_get_mp_tablesize(dbenv, mp_tablesizep)
+	DB_ENV *dbenv;
+	u_int32_t *mp_tablesizep;
+{
+	ENV *env;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_tablesize", DB_INIT_MPOOL);
+
+	*mp_tablesizep = dbenv->mp_tablesize;
+	return (0);
+}
+
+/*
+ * __memp_set_mp_tablesize --
+ *	DB_ENV->set_mp_tablesize.
+ *
+ * PUBLIC: int __memp_set_mp_tablesize __P((DB_ENV *, u_int32_t));
+ */
+int
+__memp_set_mp_tablesize(dbenv, mp_tablesize)
+	DB_ENV *dbenv;
+	u_int32_t mp_tablesize;
+{
+	ENV *env;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_mmapsize", DB_INIT_MPOOL);
+	ENV_ILLEGAL_AFTER_OPEN(env, "DB_ENV->set_mp_tablesize");
+
+	dbenv->mp_tablesize = mp_tablesize;
+	return (0);
+}
+
+/*
+ * __memp_nameop
+ *	Remove or rename a file in the pool.
+ *
+ * PUBLIC: int __memp_nameop __P((ENV *,
+ * PUBLIC:     u_int8_t *, const char *, const char *, const char *, int));
+ *
+ * XXX
+ * Undocumented interface: DB private.
+ */
+int
+__memp_nameop(env, fileid, newname, fullold, fullnew, inmem)
+	ENV *env;
+	u_int8_t *fileid;
+	const char *newname, *fullold, *fullnew;
+	int inmem;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp, *nhp;
+	MPOOL *mp;
+	MPOOLFILE *mfp;
+	roff_t newname_off;
+	u_int32_t bucket;
+	int locked, ret;
+	size_t nlen;
+	void *p;
+
+#undef	op_is_remove
+#define	op_is_remove	(newname == NULL)
+
+	COMPQUIET(bucket, 0);
+	COMPQUIET(hp, NULL);
+	COMPQUIET(newname_off, 0);
+	COMPQUIET(nlen, 0);
+
+	dbmp = NULL;
+	mfp = NULL;
+	nhp = NULL;
+	p = NULL;
+	locked = ret = 0;
+
+	if (!MPOOL_ON(env))
+		goto fsop;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+
+	if (!op_is_remove) {
+		nlen = strlen(newname);
+		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+		    NULL,  nlen + 1, &newname_off, &p)) != 0)
+			return (ret);
+		memcpy(p, newname, nlen + 1);
+	}
+
+	/*
+	 * Remove or rename a file that the mpool might know about.  We assume
+	 * that the fop layer has the file locked for exclusive access, so we
+	 * don't worry about locking except for the mpool mutexes.  Checkpoint
+	 * can happen at any time, independent of file locking, so we have to
+	 * do the actual unlink or rename system call while holding
+	 * all affected buckets locked.
+	 *
+	 * If this is a rename and this is a memory file then we need
+	 * to make sure that the new name does not exist.  Since we
+	 * are locking two buckets lock them in ascending order.
+	 */
+	if (inmem) {
+		DB_ASSERT(env, fullold != NULL);
+		hp += FNBUCKET(fullold, strlen(fullold));
+		if (!op_is_remove) {
+			bucket = FNBUCKET(newname, nlen);
+			nhp = R_ADDR(dbmp->reginfo, mp->ftab);
+			nhp += bucket;
+		}
+	} else
+		hp += FNBUCKET(fileid, DB_FILE_ID_LEN);
+
+	if (nhp != NULL && nhp < hp)
+		MUTEX_LOCK(env, nhp->mtx_hash);
+	MUTEX_LOCK(env, hp->mtx_hash);
+	if (nhp != NULL && nhp > hp)
+		MUTEX_LOCK(env, nhp->mtx_hash);
+	locked = 1;
+
+	if (!op_is_remove && inmem) {
+		SH_TAILQ_FOREACH(mfp, &nhp->hash_bucket, q, __mpoolfile)
+			if (!mfp->deadfile &&
+			    mfp->no_backing_file && strcmp(newname,
+			    R_ADDR(dbmp->reginfo, mfp->path_off)) == 0)
+				break;
+		if (mfp != NULL) {
+			ret = EEXIST;
+			goto err;
+		}
+	}
+
+	/*
+	 * Find the file -- if mpool doesn't know about this file, that may
+	 * not be an error.
+	 */
+	SH_TAILQ_FOREACH(mfp, &hp->hash_bucket, q, __mpoolfile) {
+		/* Ignore non-active files. */
+		if (mfp->deadfile || F_ISSET(mfp, MP_TEMP))
+			continue;
+
+		/* Try to match on fileid. */
+		if (memcmp(fileid, R_ADDR(
+		    dbmp->reginfo, mfp->fileid_off), DB_FILE_ID_LEN) != 0)
+			continue;
+
+		break;
+	}
+
+	if (mfp == NULL) {
+		if (inmem) {
+			ret = ENOENT;
+			goto err;
+		}
+		goto fsop;
+	}
+
+	if (op_is_remove) {
+		MUTEX_LOCK(env, mfp->mutex);
+		/*
+		 * In-memory dbs have an artificially incremented ref count so
+		 * they do not get reclaimed as long as they exist.  Since we
+		 * are now deleting the database, we need to dec that count.
+		 */
+		if (mfp->no_backing_file)
+			mfp->mpf_cnt--;
+		mfp->deadfile = 1;
+		MUTEX_UNLOCK(env, mfp->mutex);
+	} else {
+		/*
+		 * Else, it's a rename.  We've allocated memory for the new
+		 * name.  Swap it with the old one.  If it's in memory we
+		 * need to move it the right bucket.
+		 */
+		p = R_ADDR(dbmp->reginfo, mfp->path_off);
+		mfp->path_off = newname_off;
+
+		if (inmem && hp != nhp) {
+			DB_ASSERT(env, nhp != NULL);
+			SH_TAILQ_REMOVE(&hp->hash_bucket, mfp, q, __mpoolfile);
+			mfp->bucket = bucket;
+			SH_TAILQ_INSERT_TAIL(&nhp->hash_bucket, mfp, q);
+		}
+	}
+
+fsop:	/*
+	 * If this is a real file, then mfp could be NULL, because
+	 * mpool isn't turned on, and we still need to do the file ops.
+	 */
+	if (mfp == NULL || !mfp->no_backing_file) {
+		if (op_is_remove) {
+			/*
+			 * !!!
+			 * Replication may ask us to unlink a file that's been
+			 * renamed.  Don't complain if it doesn't exist.
+			 */
+			if ((ret = __os_unlink(env, fullold, 0)) == ENOENT)
+				ret = 0;
+		} else {
+			/*
+			 * Defensive only, fullnew should never be
+			 * NULL.
+			 */
+			DB_ASSERT(env, fullnew != NULL);
+			if (fullnew == NULL) {
+				ret = EINVAL;
+				goto err;
+			}
+			ret = __os_rename(env, fullold, fullnew, 1);
+		}
+	}
+
+	/* Delete the memory we no longer need. */
+err:	if (p != NULL) {
+		MPOOL_REGION_LOCK(env, &dbmp->reginfo[0]);
+		__memp_free(&dbmp->reginfo[0], p);
+		MPOOL_REGION_UNLOCK(env, &dbmp->reginfo[0]);
+	}
+
+	/* If we have buckets locked, unlock them when done moving files. */
+	if (locked == 1) {
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		if (nhp != NULL && nhp != hp)
+			MUTEX_UNLOCK(env, nhp->mtx_hash);
+	}
+	return (ret);
+}
+
+/*
+ * __memp_ftruncate __
+ *	Truncate the file.
+ *
+ * PUBLIC: int __memp_ftruncate __P((DB_MPOOLFILE *, DB_TXN *,
+ * PUBLIC:     DB_THREAD_INFO *, db_pgno_t, u_int32_t));
+ */
+int
+__memp_ftruncate(dbmfp, txn, ip, pgno, flags)
+	DB_MPOOLFILE *dbmfp;
+	DB_TXN *txn;
+	DB_THREAD_INFO *ip;
+	db_pgno_t pgno;
+	u_int32_t flags;
+{
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *pagep;
+	db_pgno_t last_pgno, pg;
+	int ret;
+
+	env = dbmfp->env;
+	mfp = dbmfp->mfp;
+	ret = 0;
+
+	MUTEX_LOCK(env, mfp->mutex);
+	last_pgno = mfp->last_pgno;
+	MUTEX_UNLOCK(env, mfp->mutex);
+
+	if (pgno > last_pgno) {
+		if (LF_ISSET(MP_TRUNC_RECOVER))
+			return (0);
+		__db_errx(env, "Truncate beyond the end of file");
+		return (EINVAL);
+	}
+
+	pg = pgno;
+	do {
+		if (mfp->block_cnt == 0)
+			break;
+		if ((ret = __memp_fget(dbmfp, &pg,
+		    ip, txn, DB_MPOOL_FREE, &pagep)) != 0)
+			return (ret);
+	} while (pg++ < last_pgno);
+
+	/*
+	 * If we are aborting an extend of a file, the call to __os_truncate
+	 * could extend the file if the new page(s) had not yet been
+	 * written to disk.  We do not want to extend the file to pages
+	 * whose log records are not yet flushed [#14031].  In addition if
+	 * we are out of disk space we can generate an error [#12743].
+	 */
+	MUTEX_LOCK(env, mfp->mutex);
+	if (!F_ISSET(mfp, MP_TEMP) &&
+	    !mfp->no_backing_file && pgno <= mfp->last_flushed_pgno)
+#ifdef HAVE_FTRUNCATE
+		ret = __os_truncate(env,
+		    dbmfp->fhp, pgno, mfp->stat.st_pagesize);
+#else
+		ret = __db_zero_extend(env,
+		    dbmfp->fhp, pgno, mfp->last_pgno, mfp->stat.st_pagesize);
+#endif
+
+	/*
+	 * This set could race with another thread of control that extending
+	 * the file.  It's not a problem because we should have the page
+	 * locked at a higher level of the system.
+	 */
+	if (ret == 0) {
+		mfp->last_pgno = pgno - 1;
+		if (mfp->last_flushed_pgno > mfp->last_pgno)
+			mfp->last_flushed_pgno = mfp->last_pgno;
+	}
+	MUTEX_UNLOCK(env, mfp->mutex);
+
+	return (ret);
+}
+
+#ifdef HAVE_FTRUNCATE
+/*
+ * Support routines for maintaining a sorted freelist while we try to rearrange
+ * and truncate the file.
+ */
+
+/*
+ * __memp_alloc_freelist --
+ *	Allocate mpool space for the freelist.
+ *
+ * PUBLIC: int __memp_alloc_freelist __P((DB_MPOOLFILE *,
+ * PUBLIC:	 u_int32_t, db_pgno_t **));
+ */
+int
+__memp_alloc_freelist(dbmfp, nelems, listp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t nelems;
+	db_pgno_t **listp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *retp;
+	int ret;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+
+	*listp = NULL;
+
+	/*
+	 * These fields are protected because the database layer
+	 * has the metapage locked while manipulating them.
+	 */
+	mfp->free_ref++;
+	if (mfp->free_size != 0)
+		return (EBUSY);
+
+	/* Allocate at least a few slots. */
+	mfp->free_cnt = nelems;
+	if (nelems == 0)
+		nelems = 50;
+
+	if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+	    NULL, nelems * sizeof(db_pgno_t), &mfp->free_list, &retp)) != 0)
+		return (ret);
+
+	mfp->free_size = nelems * sizeof(db_pgno_t);
+	*listp = retp;
+	return (0);
+}
+
+/*
+ * __memp_free_freelist --
+ *	Free the list.
+ *
+ * PUBLIC: int __memp_free_freelist __P((DB_MPOOLFILE *));
+ */
+int
+__memp_free_freelist(dbmfp)
+	DB_MPOOLFILE *dbmfp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOLFILE *mfp;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+
+	DB_ASSERT(env, mfp->free_ref > 0);
+	if (--mfp->free_ref > 0)
+		return (0);
+
+	DB_ASSERT(env, mfp->free_size != 0);
+
+	MPOOL_SYSTEM_LOCK(env);
+	__memp_free(dbmp->reginfo, R_ADDR(dbmp->reginfo, mfp->free_list));
+	MPOOL_SYSTEM_UNLOCK(env);
+
+	mfp->free_cnt = 0;
+	mfp->free_list = 0;
+	mfp->free_size = 0;
+	return (0);
+}
+
+/*
+ * __memp_get_freelst --
+ *	Return current list.
+ *
+ * PUBLIC: int __memp_get_freelist __P((
+ * PUBLIC:	DB_MPOOLFILE *, u_int32_t *, db_pgno_t **));
+ */
+int
+__memp_get_freelist(dbmfp, nelemp, listp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t *nelemp;
+	db_pgno_t **listp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOLFILE *mfp;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+
+	if (mfp->free_size == 0) {
+		*nelemp = 0;
+		*listp = NULL;
+	} else {
+		*nelemp = mfp->free_cnt;
+		*listp = R_ADDR(dbmp->reginfo, mfp->free_list);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_extend_freelist --
+ *	Extend the list.
+ *
+ * PUBLIC: int __memp_extend_freelist __P((
+ * PUBLIC:	DB_MPOOLFILE *, u_int32_t , db_pgno_t **));
+ */
+int
+__memp_extend_freelist(dbmfp, count, listp)
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t count;
+	db_pgno_t **listp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOLFILE *mfp;
+	int ret;
+	void *retp;
+
+	env = dbmfp->env;
+	dbmp = env->mp_handle;
+	mfp = dbmfp->mfp;
+
+	if (mfp->free_size == 0)
+		return (EINVAL);
+
+	if (count * sizeof(db_pgno_t) > mfp->free_size) {
+		mfp->free_size =
+		     (size_t)DB_ALIGN(count * sizeof(db_pgno_t), 512);
+		*listp = R_ADDR(dbmp->reginfo, mfp->free_list);
+		if ((ret = __memp_alloc(dbmp, dbmp->reginfo,
+		    NULL, mfp->free_size, &mfp->free_list, &retp)) != 0)
+			return (ret);
+
+		memcpy(retp, *listp, mfp->free_cnt * sizeof(db_pgno_t));
+
+		MPOOL_SYSTEM_LOCK(env);
+		__memp_free(dbmp->reginfo, *listp);
+		MPOOL_SYSTEM_UNLOCK(env);
+	}
+
+	mfp->free_cnt = count;
+	*listp = R_ADDR(dbmp->reginfo, mfp->free_list);
+
+	return (0);
+}
+#endif
+
+/*
+ * __memp_set_last_pgno -- set the last page of the file
+ *
+ * PUBLIC: void __memp_set_last_pgno __P((DB_MPOOLFILE *, db_pgno_t));
+ */
+void
+__memp_set_last_pgno(dbmfp, pgno)
+	DB_MPOOLFILE *dbmfp;
+	db_pgno_t pgno;
+{
+	dbmfp->mfp->last_pgno = pgno;
+}
diff --git a/mp/mp_mvcc.c b/mp/mp_mvcc.c
new file mode 100644
index 0000000..34467d2
--- /dev/null
+++ b/mp/mp_mvcc.c
@@ -0,0 +1,634 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2006-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+static int __pgno_cmp __P((const void *, const void *));
+
+/*
+ * __memp_bh_settxn --
+ *	Set the transaction that owns the given buffer.
+ *
+ * PUBLIC: int __memp_bh_settxn __P((DB_MPOOL *, MPOOLFILE *mfp, BH *, void *));
+ */
+int
+__memp_bh_settxn(dbmp, mfp, bhp, vtd)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+	BH *bhp;
+	void *vtd;
+{
+	ENV *env;
+	TXN_DETAIL *td;
+
+	env = dbmp->env;
+	td = (TXN_DETAIL *)vtd;
+
+	if (td == NULL) {
+		__db_errx(env,
+		      "%s: non-transactional update to a multiversion file",
+		    __memp_fns(dbmp, mfp));
+		return (EINVAL);
+	}
+
+	if (bhp->td_off != INVALID_ROFF) {
+		DB_ASSERT(env, BH_OWNER(env, bhp) == td);
+		return (0);
+	}
+
+	bhp->td_off = R_OFFSET(&env->tx_handle->reginfo, td);
+	return (__txn_add_buffer(env, td));
+}
+
+/*
+ * __memp_skip_curadj --
+ *	Indicate whether a cursor adjustment can be skipped for a snapshot
+ *	cursor.
+ *
+ * PUBLIC: int __memp_skip_curadj __P((DBC *, db_pgno_t));
+ */
+int
+__memp_skip_curadj(dbc, pgno)
+	DBC * dbc;
+	db_pgno_t pgno;
+{
+	BH *bhp;
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	DB_MPOOL_HASH *hp;
+	DB_TXN *txn;
+	ENV *env;
+	MPOOLFILE *mfp;
+	REGINFO *infop;
+	roff_t mf_offset;
+	int ret, skip;
+	u_int32_t bucket;
+
+	env = dbc->env;
+	dbmp = env->mp_handle;
+	dbmfp = dbc->dbp->mpf;
+	mfp = dbmfp->mfp;
+	mf_offset = R_OFFSET(dbmp->reginfo, mfp);
+	skip = 0;
+
+	for (txn = dbc->txn; txn->parent != NULL; txn = txn->parent)
+		;
+
+	/*
+	 * Determine the cache and hash bucket where this page lives and get
+	 * local pointers to them.  Reset on each pass through this code, the
+	 * page number can change.
+	 */
+	MP_GET_BUCKET(env, mfp, pgno, &infop, hp, bucket, ret);
+	if (ret != 0) {
+		/* Panic: there is no way to return the error. */
+		(void)__env_panic(env, ret);
+		return (0);
+	}
+
+	SH_TAILQ_FOREACH(bhp, &hp->hash_bucket, hq, __bh) {
+		if (bhp->pgno != pgno || bhp->mf_offset != mf_offset)
+			continue;
+
+		if (!BH_OWNED_BY(env, bhp, txn))
+			skip = 1;
+		break;
+	}
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+
+	return (skip);
+}
+
+#define	DB_FREEZER_MAGIC 0x06102002
+
+/*
+ * __memp_bh_freeze --
+ *	Save a buffer to temporary storage in case it is needed later by
+ *	a snapshot transaction.  This function should be called with the buffer
+ *	locked and will exit with it locked.  A BH_FROZEN buffer header is
+ *	allocated to represent the frozen data in mpool.
+ *
+ * PUBLIC: int __memp_bh_freeze __P((DB_MPOOL *, REGINFO *, DB_MPOOL_HASH *,
+ * PUBLIC:     BH *, int *));
+ */
+int
+__memp_bh_freeze(dbmp, infop, hp, bhp, need_frozenp)
+	DB_MPOOL *dbmp;
+	REGINFO *infop;
+	DB_MPOOL_HASH *hp;
+	BH *bhp;
+	int *need_frozenp;
+{
+	BH *frozen_bhp;
+	BH_FROZEN_ALLOC *frozen_alloc;
+	DB_FH *fhp;
+	ENV *env;
+	MPOOL *c_mp;
+	MPOOLFILE *mfp;
+	db_mutex_t mutex;
+	db_pgno_t maxpgno, newpgno, nextfree;
+	size_t nio;
+	int created, h_locked, ret, t_ret;
+	u_int32_t magic, nbucket, ncache, pagesize;
+	char filename[100], *real_name;
+
+	env = dbmp->env;
+	c_mp = infop->primary;
+	created = h_locked = ret = 0;
+	/* Find the associated MPOOLFILE. */
+	mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+	pagesize = mfp->stat.st_pagesize;
+	real_name = NULL;
+	fhp = NULL;
+
+	MVCC_MPROTECT(bhp->buf, pagesize, PROT_READ | PROT_WRITE);
+
+	MPOOL_REGION_LOCK(env, infop);
+	frozen_bhp = SH_TAILQ_FIRST(&c_mp->free_frozen, __bh);
+	if (frozen_bhp != NULL) {
+		SH_TAILQ_REMOVE(&c_mp->free_frozen, frozen_bhp, hq, __bh);
+		*need_frozenp = SH_TAILQ_EMPTY(&c_mp->free_frozen);
+	} else {
+		*need_frozenp = 1;
+
+		/* There might be a small amount of unallocated space. */
+		if (__env_alloc(infop,
+		    sizeof(BH_FROZEN_ALLOC) + sizeof(BH_FROZEN_PAGE),
+		    &frozen_alloc) == 0) {
+			frozen_bhp = (BH *)(frozen_alloc + 1);
+			frozen_bhp->mtx_buf = MUTEX_INVALID;
+			SH_TAILQ_INSERT_TAIL(&c_mp->alloc_frozen,
+			    frozen_alloc, links);
+		}
+	}
+	MPOOL_REGION_UNLOCK(env, infop);
+
+	/*
+	 * If we can't get a frozen buffer header, return ENOMEM immediately:
+	 * we don't want to call __memp_alloc recursively.  __memp_alloc will
+	 * turn the next free page it finds into frozen buffer headers.
+	 */
+	if (frozen_bhp == NULL) {
+		ret = ENOMEM;
+		goto err;
+	}
+
+	/*
+	 * For now, keep things simple and have one file per page size per
+	 * hash bucket.  This improves concurrency but can mean lots of files
+	 * if there is lots of freezing.
+	 */
+	ncache = (u_int32_t)(infop - dbmp->reginfo);
+	nbucket = (u_int32_t)(hp - (DB_MPOOL_HASH *)R_ADDR(infop, c_mp->htab));
+	snprintf(filename, sizeof(filename), "__db.freezer.%lu.%lu.%luK",
+	    (u_long)ncache, (u_long)nbucket, (u_long)pagesize / 1024);
+
+	if ((ret = __db_appname(env,
+	    DB_APP_NONE, filename, NULL, &real_name)) != 0)
+		goto err;
+
+	MUTEX_LOCK(env, hp->mtx_hash);
+	h_locked = 1;
+	DB_ASSERT(env, F_ISSET(bhp, BH_EXCLUSIVE) && !F_ISSET(bhp, BH_FROZEN));
+
+	if (BH_REFCOUNT(bhp) > 1 || F_ISSET(bhp, BH_DIRTY)) {
+		ret = EBUSY;
+		goto err;
+	}
+
+	if ((ret = __os_open(env, real_name, pagesize,
+	    DB_OSO_CREATE | DB_OSO_EXCL, env->db_mode, &fhp)) == 0) {
+		/* We're creating the file -- initialize the metadata page. */
+		created = 1;
+		magic = DB_FREEZER_MAGIC;
+		maxpgno = newpgno = 0;
+		if ((ret = __os_write(env, fhp,
+		    &magic, sizeof(u_int32_t), &nio)) != 0 ||
+		    (ret = __os_write(env, fhp,
+		    &newpgno, sizeof(db_pgno_t), &nio)) != 0 ||
+		    (ret = __os_write(env, fhp,
+		    &maxpgno, sizeof(db_pgno_t), &nio)) != 0 ||
+		    (ret = __os_seek(env, fhp, 0, 0, 0)) != 0)
+			goto err;
+	} else if (ret == EEXIST)
+		ret = __os_open(env,
+		    real_name, pagesize, 0, env->db_mode, &fhp);
+	if (ret != 0)
+		goto err;
+	if ((ret = __os_read(env, fhp,
+	    &magic, sizeof(u_int32_t), &nio)) != 0 ||
+	    (ret = __os_read(env, fhp,
+	    &newpgno, sizeof(db_pgno_t), &nio)) != 0 ||
+	    (ret = __os_read(env, fhp,
+	    &maxpgno, sizeof(db_pgno_t), &nio)) != 0)
+		goto err;
+	if (magic != DB_FREEZER_MAGIC) {
+		ret = EINVAL;
+		goto err;
+	}
+	if (newpgno == 0) {
+		newpgno = ++maxpgno;
+		if ((ret = __os_seek(env,
+		    fhp, 0, 0, sizeof(u_int32_t) + sizeof(db_pgno_t))) != 0 ||
+		    (ret = __os_write(env, fhp, &maxpgno, sizeof(db_pgno_t),
+		    &nio)) != 0)
+			goto err;
+	} else {
+		if ((ret = __os_seek(env, fhp, newpgno, pagesize, 0)) != 0 ||
+		    (ret = __os_read(env, fhp, &nextfree, sizeof(db_pgno_t),
+		    &nio)) != 0)
+			goto err;
+		if ((ret =
+		    __os_seek(env, fhp, 0, 0, sizeof(u_int32_t))) != 0 ||
+		    (ret = __os_write(env, fhp, &nextfree, sizeof(db_pgno_t),
+		    &nio)) != 0)
+			goto err;
+	}
+
+	/* Write the buffer to the allocated page. */
+	if ((ret = __os_io(env, DB_IO_WRITE, fhp, newpgno, pagesize, 0,
+	    pagesize, bhp->buf, &nio)) != 0)
+		goto err;
+
+	ret = __os_closehandle(env, fhp);
+	fhp = NULL;
+	if (ret != 0)
+		goto err;
+
+	/*
+	 * Set up the frozen_bhp with the freezer page number.  The original
+	 * buffer header is about to be freed, so transfer resources to the
+	 * frozen header here.
+	 */
+	mutex = frozen_bhp->mtx_buf;
+#ifdef DIAG_MVCC
+	memcpy(frozen_bhp, bhp, SSZ(BH, align_off));
+#else
+	memcpy(frozen_bhp, bhp, SSZA(BH, buf));
+#endif
+	atomic_init(&frozen_bhp->ref, 0);
+	if (mutex != MUTEX_INVALID)
+		frozen_bhp->mtx_buf = mutex;
+	else if ((ret = __mutex_alloc(env, MTX_MPOOL_BH,
+	    DB_MUTEX_SHARED, &frozen_bhp->mtx_buf)) != 0)
+		goto err;
+	F_SET(frozen_bhp, BH_FROZEN);
+	F_CLR(frozen_bhp, BH_EXCLUSIVE);
+	((BH_FROZEN_PAGE *)frozen_bhp)->spgno = newpgno;
+
+	/*
+	 * We're about to add the frozen buffer header to the version chain, so
+	 * we have temporarily created another buffer for the owning
+	 * transaction.
+	 */
+	if (frozen_bhp->td_off != INVALID_ROFF &&
+	    (ret = __txn_add_buffer(env, BH_OWNER(env, frozen_bhp))) != 0) {
+		(void)__env_panic(env, ret);
+		goto err;
+	}
+
+	/*
+	 * Add the frozen buffer to the version chain and update the hash
+	 * bucket if this is the head revision.  The original buffer will be
+	 * freed by __memp_alloc calling __memp_bhfree (assuming no other
+	 * thread has blocked waiting for it while we were freezing).
+	 */
+	SH_CHAIN_INSERT_AFTER(bhp, frozen_bhp, vc, __bh);
+	if (!SH_CHAIN_HASNEXT(frozen_bhp, vc)) {
+		SH_TAILQ_INSERT_BEFORE(&hp->hash_bucket,
+		    bhp, frozen_bhp, hq, __bh);
+		SH_TAILQ_REMOVE(&hp->hash_bucket, bhp, hq, __bh);
+	}
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+	h_locked = 0;
+
+	/*
+	 * Increment the file's block count -- freeing the original buffer will
+	 * decrement it.
+	 */
+	MUTEX_LOCK(env, mfp->mutex);
+	++mfp->block_cnt;
+	MUTEX_UNLOCK(env, mfp->mutex);
+
+	STAT(++hp->hash_frozen);
+
+	if (0) {
+err:		if (fhp != NULL &&
+		    (t_ret = __os_closehandle(env, fhp)) != 0 && ret == 0)
+			ret = t_ret;
+		if (created) {
+			DB_ASSERT(env, h_locked);
+			if ((t_ret = __os_unlink(env, real_name, 0)) != 0 &&
+			    ret == 0)
+				ret = t_ret;
+		}
+		if (h_locked)
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+		if (ret == 0)
+			ret = EIO;
+		if (frozen_bhp != NULL) {
+			MPOOL_REGION_LOCK(env, infop);
+			SH_TAILQ_INSERT_TAIL(&c_mp->free_frozen,
+			    frozen_bhp, hq);
+			MPOOL_REGION_UNLOCK(env, infop);
+		}
+	}
+	if (real_name != NULL)
+		__os_free(env, real_name);
+	if (ret != 0 && ret != EBUSY && ret != ENOMEM)
+		__db_err(env, ret, "__memp_bh_freeze");
+
+	return (ret);
+}
+
+static int
+__pgno_cmp(a, b)
+	const void *a, *b;
+{
+	db_pgno_t *ap, *bp;
+
+	ap = (db_pgno_t *)a;
+	bp = (db_pgno_t *)b;
+
+	return (int)(*ap - *bp);
+}
+
+/*
+ * __memp_bh_thaw --
+ *	Free a buffer header in temporary storage.  Optionally restore the
+ *	buffer (if alloc_bhp != NULL).  This function should be
+ *	called with the hash bucket locked and will return with it unlocked.
+ *
+ * PUBLIC: int __memp_bh_thaw __P((DB_MPOOL *, REGINFO *,
+ * PUBLIC:	DB_MPOOL_HASH *, BH *, BH *));
+ */
+int
+__memp_bh_thaw(dbmp, infop, hp, frozen_bhp, alloc_bhp)
+	DB_MPOOL *dbmp;
+	REGINFO *infop;
+	DB_MPOOL_HASH *hp;
+	BH *frozen_bhp, *alloc_bhp;
+{
+	DB_FH *fhp;
+	ENV *env;
+#ifdef DIAGNOSTIC
+	DB_LSN vlsn;
+#endif
+	MPOOL *c_mp;
+	MPOOLFILE *mfp;
+	db_mutex_t mutex;
+	db_pgno_t *freelist, *ppgno, freepgno, maxpgno, spgno;
+	size_t nio;
+	u_int32_t listsize, magic, nbucket, ncache, ntrunc, nfree, pagesize;
+#ifdef HAVE_FTRUNCATE
+	int i;
+#endif
+	int h_locked, needfree, ret, t_ret;
+	char filename[100], *real_name;
+
+	env = dbmp->env;
+	fhp = NULL;
+	c_mp = infop->primary;
+	mfp = R_ADDR(dbmp->reginfo, frozen_bhp->mf_offset);
+	freelist = NULL;
+	pagesize = mfp->stat.st_pagesize;
+	ret = 0;
+	real_name = NULL;
+
+	MUTEX_REQUIRED(env, hp->mtx_hash);
+	DB_ASSERT(env, F_ISSET(frozen_bhp, BH_EXCLUSIVE) || alloc_bhp == NULL);
+	h_locked = 1;
+
+	DB_ASSERT(env, F_ISSET(frozen_bhp, BH_FROZEN) &&
+	    !F_ISSET(frozen_bhp, BH_THAWED));
+	DB_ASSERT(env, alloc_bhp != NULL ||
+	    SH_CHAIN_SINGLETON(frozen_bhp, vc) ||
+	    (SH_CHAIN_HASNEXT(frozen_bhp, vc) &&
+	    BH_OBSOLETE(frozen_bhp, hp->old_reader, vlsn)));
+	DB_ASSERT(env, alloc_bhp == NULL || !F_ISSET(alloc_bhp, BH_FROZEN));
+
+	spgno = ((BH_FROZEN_PAGE *)frozen_bhp)->spgno;
+
+	if (alloc_bhp != NULL) {
+		mutex = alloc_bhp->mtx_buf;
+#ifdef DIAG_MVCC
+		memcpy(alloc_bhp, frozen_bhp, SSZ(BH, align_off));
+#else
+		memcpy(alloc_bhp, frozen_bhp, SSZA(BH, buf));
+#endif
+		alloc_bhp->mtx_buf = mutex;
+		MUTEX_LOCK(env, alloc_bhp->mtx_buf);
+		atomic_init(&alloc_bhp->ref, 1);
+		F_CLR(alloc_bhp, BH_FROZEN);
+	}
+
+	/*
+	 * For now, keep things simple and have one file per page size per
+	 * hash bucket.  This improves concurrency but can mean lots of files
+	 * if there is lots of freezing.
+	 */
+	ncache = (u_int32_t)(infop - dbmp->reginfo);
+	nbucket = (u_int32_t)(hp - (DB_MPOOL_HASH *)R_ADDR(infop, c_mp->htab));
+	snprintf(filename, sizeof(filename), "__db.freezer.%lu.%lu.%luK",
+	    (u_long)ncache, (u_long)nbucket, (u_long)pagesize / 1024);
+
+	if ((ret = __db_appname(env,
+	    DB_APP_NONE, filename, NULL, &real_name)) != 0)
+		goto err;
+	if ((ret = __os_open(env,
+	    real_name, pagesize, 0, env->db_mode, &fhp)) != 0)
+		goto err;
+
+	/*
+	 * Read the first free page number -- we're about to free the page
+	 * after we we read it.
+	 */
+	if ((ret = __os_read(env, fhp, &magic, sizeof(u_int32_t), &nio)) != 0 ||
+	    (ret =
+	    __os_read(env, fhp, &freepgno, sizeof(db_pgno_t), &nio)) != 0 ||
+	    (ret = __os_read(env, fhp, &maxpgno, sizeof(db_pgno_t), &nio)) != 0)
+		goto err;
+
+	if (magic != DB_FREEZER_MAGIC) {
+		ret = EINVAL;
+		goto err;
+	}
+
+	/* Read the buffer from the frozen page. */
+	if (alloc_bhp != NULL) {
+		DB_ASSERT(env, !F_ISSET(frozen_bhp, BH_FREED));
+		if ((ret = __os_io(env, DB_IO_READ, fhp,
+		    spgno, pagesize, 0, pagesize, alloc_bhp->buf, &nio)) != 0)
+			goto err;
+	}
+
+	/*
+	 * Free the page from the file.  If it's the last page, truncate.
+	 * Otherwise, update free page linked list.
+	 */
+	needfree = 1;
+	if (spgno == maxpgno) {
+		listsize = 100;
+		if ((ret = __os_malloc(env,
+		    listsize * sizeof(db_pgno_t), &freelist)) != 0)
+			goto err;
+		nfree = 0;
+		while (freepgno != 0) {
+			if (nfree == listsize - 1) {
+				listsize *= 2;
+				if ((ret = __os_realloc(env,
+				    listsize * sizeof(db_pgno_t),
+				    &freelist)) != 0)
+					goto err;
+			}
+			freelist[nfree++] = freepgno;
+			if ((ret = __os_seek(env, fhp,
+			    freepgno, pagesize, 0)) != 0 ||
+			    (ret = __os_read(env, fhp, &freepgno,
+			    sizeof(db_pgno_t), &nio)) != 0)
+				goto err;
+		}
+		freelist[nfree++] = spgno;
+		qsort(freelist, nfree, sizeof(db_pgno_t), __pgno_cmp);
+		for (ppgno = &freelist[nfree - 1]; ppgno > freelist; ppgno--)
+			if (*(ppgno - 1) != *ppgno - 1)
+				break;
+		ntrunc = (u_int32_t)(&freelist[nfree] - ppgno);
+		if (ntrunc == (u_int32_t)maxpgno) {
+			needfree = 0;
+			ret = __os_closehandle(env, fhp);
+			fhp = NULL;
+			if (ret != 0 ||
+			    (ret = __os_unlink(env, real_name, 0)) != 0)
+				goto err;
+		}
+#ifdef HAVE_FTRUNCATE
+		else {
+			maxpgno -= (db_pgno_t)ntrunc;
+			if ((ret = __os_truncate(env, fhp,
+			    maxpgno + 1, pagesize)) != 0)
+				goto err;
+
+			/* Fix up the linked list */
+			freelist[nfree - ntrunc] = 0;
+			if ((ret = __os_seek(env, fhp,
+			    0, 0, sizeof(u_int32_t))) != 0 ||
+			    (ret = __os_write(env, fhp, &freelist[0],
+			    sizeof(db_pgno_t), &nio)) != 0 ||
+			    (ret = __os_write(env, fhp, &maxpgno,
+			    sizeof(db_pgno_t), &nio)) != 0)
+				goto err;
+
+			for (i = 0; i < (int)(nfree - ntrunc); i++)
+				if ((ret = __os_seek(env,
+				    fhp, freelist[i], pagesize, 0)) != 0 ||
+				    (ret = __os_write(env, fhp,
+				    &freelist[i + 1], sizeof(db_pgno_t),
+				    &nio)) != 0)
+					goto err;
+			needfree = 0;
+		}
+#endif
+	}
+	if (needfree) {
+		if ((ret = __os_seek(env, fhp, spgno, pagesize, 0)) != 0 ||
+		    (ret = __os_write(env, fhp,
+		    &freepgno, sizeof(db_pgno_t), &nio)) != 0 ||
+	    	    (ret = __os_seek(env, fhp, 0, 0, sizeof(u_int32_t))) != 0 ||
+		    (ret = __os_write(env, fhp,
+		    &spgno, sizeof(db_pgno_t), &nio)) != 0)
+			goto err;
+
+		ret = __os_closehandle(env, fhp);
+		fhp = NULL;
+		if (ret != 0)
+			goto err;
+	}
+
+	/*
+	 * Add the thawed buffer (if any) to the version chain.  We can't
+	 * do this any earlier, because we can't guarantee that another thread
+	 * won't be waiting for it, which means we can't clean up if there are
+	 * errors reading from the freezer.  We can't do it any later, because
+	 * we're about to free frozen_bhp, and without it we would need to do
+	 * another cache lookup to find out where the new page should live.
+	 */
+	MUTEX_REQUIRED(env, hp->mtx_hash);
+	if (alloc_bhp != NULL) {
+		alloc_bhp->priority = c_mp->lru_count;
+
+		SH_CHAIN_INSERT_AFTER(frozen_bhp, alloc_bhp, vc, __bh);
+		if (!SH_CHAIN_HASNEXT(alloc_bhp, vc)) {
+			SH_TAILQ_INSERT_BEFORE(&hp->hash_bucket, frozen_bhp,
+			    alloc_bhp, hq, __bh);
+			SH_TAILQ_REMOVE(&hp->hash_bucket, frozen_bhp, hq, __bh);
+		}
+	} else if (!SH_CHAIN_HASNEXT(frozen_bhp, vc)) {
+		if (SH_CHAIN_HASPREV(frozen_bhp, vc))
+			SH_TAILQ_INSERT_BEFORE(&hp->hash_bucket, frozen_bhp,
+			    SH_CHAIN_PREV(frozen_bhp, vc, __bh), hq, __bh);
+		SH_TAILQ_REMOVE(&hp->hash_bucket, frozen_bhp, hq, __bh);
+	}
+	SH_CHAIN_REMOVE(frozen_bhp, vc, __bh);
+
+	if (alloc_bhp == NULL && frozen_bhp->td_off != INVALID_ROFF &&
+	    (ret = __txn_remove_buffer(env,
+	    BH_OWNER(env, frozen_bhp), MUTEX_INVALID)) != 0) {
+		(void)__env_panic(env, ret);
+		goto err;
+	}
+	frozen_bhp->td_off = INVALID_ROFF;
+
+	/*
+	 * If other threads are waiting for this buffer as well, they will have
+	 * incremented the reference count and will be waiting on the mutex.
+	 * For that reason, we can't unconditionally free the memory here.
+	 */
+	needfree = (atomic_dec(env, &frozen_bhp->ref) == 0);
+	if (!needfree)
+		F_SET(frozen_bhp, BH_THAWED);
+	MUTEX_UNLOCK(env, hp->mtx_hash);
+	if (F_ISSET(frozen_bhp, BH_EXCLUSIVE))
+		MUTEX_UNLOCK(env, frozen_bhp->mtx_buf);
+	h_locked = 0;
+	if (needfree) {
+		MPOOL_REGION_LOCK(env, infop);
+		SH_TAILQ_INSERT_TAIL(&c_mp->free_frozen, frozen_bhp, hq);
+		MPOOL_REGION_UNLOCK(env, infop);
+	}
+
+#ifdef HAVE_STATISTICS
+	if (alloc_bhp != NULL)
+		++hp->hash_thawed;
+	else
+		++hp->hash_frozen_freed;
+#endif
+
+	if (0) {
+err:		if (h_locked)
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+		if (ret == 0)
+			ret = EIO;
+	}
+	if (real_name != NULL)
+		__os_free(env, real_name);
+	if (freelist != NULL)
+		__os_free(env, freelist);
+	if (fhp != NULL &&
+	    (t_ret = __os_closehandle(env, fhp)) != 0 && ret == 0)
+		ret = t_ret;
+	if (ret != 0)
+		__db_err(env, ret, "__memp_bh_thaw");
+
+	return (ret);
+}
diff --git a/mp/mp_region.c b/mp/mp_region.c
new file mode 100644
index 0000000..e6cece9
--- /dev/null
+++ b/mp/mp_region.c
@@ -0,0 +1,588 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/mp.h"
+
+static int	__memp_init_config __P((ENV *, MPOOL *));
+static void	__memp_region_size __P((ENV *, roff_t *, u_int32_t *));
+
+#define	MPOOL_DEFAULT_PAGESIZE	(4 * 1024)
+
+/*
+ * __memp_open --
+ *	Internal version of memp_open: only called from ENV->open.
+ *
+ * PUBLIC: int __memp_open __P((ENV *, int));
+ */
+int
+__memp_open(env, create_ok)
+	ENV *env;
+	int create_ok;
+{
+	DB_ENV *dbenv;
+	DB_MPOOL *dbmp;
+	MPOOL *mp;
+	REGINFO reginfo;
+	roff_t reg_size;
+	u_int i, max_nreg;
+	u_int32_t htab_buckets, *regids;
+	int ret;
+
+	dbenv = env->dbenv;
+
+	/* Calculate the region size and hash bucket count. */
+	__memp_region_size(env, &reg_size, &htab_buckets);
+
+	/* Create and initialize the DB_MPOOL structure. */
+	if ((ret = __os_calloc(env, 1, sizeof(*dbmp), &dbmp)) != 0)
+		return (ret);
+	LIST_INIT(&dbmp->dbregq);
+	TAILQ_INIT(&dbmp->dbmfq);
+	dbmp->env = env;
+
+	/* Join/create the first mpool region. */
+	memset(&reginfo, 0, sizeof(REGINFO));
+	reginfo.env = env;
+	reginfo.type = REGION_TYPE_MPOOL;
+	reginfo.id = INVALID_REGION_ID;
+	reginfo.flags = REGION_JOIN_OK;
+	if (create_ok)
+		F_SET(&reginfo, REGION_CREATE_OK);
+	if ((ret = __env_region_attach(env, &reginfo, reg_size)) != 0)
+		goto err;
+
+	/*
+	 * If we created the region, initialize it.  Create or join any
+	 * additional regions.
+	 */
+	if (F_ISSET(&reginfo, REGION_CREATE)) {
+		/*
+		 * We define how many regions there are going to be, allocate
+		 * the REGINFO structures and create them.  Make sure we don't
+		 * clear the wrong entries on error.
+		 */
+		max_nreg = __memp_max_regions(env);
+		if ((ret = __os_calloc(env,
+		    max_nreg, sizeof(REGINFO), &dbmp->reginfo)) != 0)
+			goto err;
+		/* Make sure we don't clear the wrong entries on error. */
+		dbmp->reginfo[0] = reginfo;
+		for (i = 1; i < max_nreg; ++i)
+			dbmp->reginfo[i].id = INVALID_REGION_ID;
+
+		/* Initialize the first region. */
+		if ((ret = __memp_init(env, dbmp,
+		    0, htab_buckets, max_nreg)) != 0)
+			goto err;
+
+		/*
+		 * Create/initialize remaining regions and copy their IDs into
+		 * the first region.
+		 */
+		mp = R_ADDR(dbmp->reginfo, dbmp->reginfo[0].rp->primary);
+		regids = R_ADDR(dbmp->reginfo, mp->regids);
+		regids[0] = dbmp->reginfo[0].id;
+		for (i = 1; i < dbenv->mp_ncache; ++i) {
+			dbmp->reginfo[i].env = env;
+			dbmp->reginfo[i].type = REGION_TYPE_MPOOL;
+			dbmp->reginfo[i].id = INVALID_REGION_ID;
+			dbmp->reginfo[i].flags = REGION_CREATE_OK;
+			if ((ret = __env_region_attach(
+			    env, &dbmp->reginfo[i], reg_size)) != 0)
+				goto err;
+			if ((ret = __memp_init(env, dbmp,
+			    i, htab_buckets, max_nreg)) != 0)
+				goto err;
+
+			regids[i] = dbmp->reginfo[i].id;
+		}
+	} else {
+		/*
+		 * Determine how many regions there are going to be, allocate
+		 * the REGINFO structures and fill in local copies of that
+		 * information.
+		 */
+		mp = R_ADDR(&reginfo, reginfo.rp->primary);
+		dbenv->mp_ncache = mp->nreg;
+		if ((ret = __os_calloc(env,
+		    mp->max_nreg, sizeof(REGINFO), &dbmp->reginfo)) != 0)
+			goto err;
+		/* Make sure we don't clear the wrong entries on error. */
+		for (i = 0; i < dbenv->mp_ncache; ++i)
+			dbmp->reginfo[i].id = INVALID_REGION_ID;
+		dbmp->reginfo[0] = reginfo;
+
+		/* Join remaining regions. */
+		regids = R_ADDR(dbmp->reginfo, mp->regids);
+		for (i = 1; i < dbenv->mp_ncache; ++i) {
+			dbmp->reginfo[i].env = env;
+			dbmp->reginfo[i].type = REGION_TYPE_MPOOL;
+			dbmp->reginfo[i].id = regids[i];
+			dbmp->reginfo[i].flags = REGION_JOIN_OK;
+			if ((ret = __env_region_attach(
+			    env, &dbmp->reginfo[i], 0)) != 0)
+				goto err;
+		}
+	}
+
+	/* Set the local addresses for the regions. */
+	for (i = 0; i < dbenv->mp_ncache; ++i)
+		dbmp->reginfo[i].primary =
+		    R_ADDR(&dbmp->reginfo[i], dbmp->reginfo[i].rp->primary);
+
+	/* If the region is threaded, allocate a mutex to lock the handles. */
+	if ((ret = __mutex_alloc(env,
+	    MTX_MPOOL_HANDLE, DB_MUTEX_PROCESS_ONLY, &dbmp->mutex)) != 0)
+		goto err;
+
+	env->mp_handle = dbmp;
+
+	/* A process joining the region may reset the mpool configuration. */
+	if ((ret = __memp_init_config(env, mp)) != 0)
+		return (ret);
+
+	return (0);
+
+err:	env->mp_handle = NULL;
+	if (dbmp->reginfo != NULL && dbmp->reginfo[0].addr != NULL) {
+		for (i = 0; i < dbenv->mp_ncache; ++i)
+			if (dbmp->reginfo[i].id != INVALID_REGION_ID)
+				(void)__env_region_detach(
+				    env, &dbmp->reginfo[i], 0);
+		__os_free(env, dbmp->reginfo);
+	}
+
+	(void)__mutex_free(env, &dbmp->mutex);
+	__os_free(env, dbmp);
+	return (ret);
+}
+
+/*
+ * __memp_init --
+ *	Initialize a MPOOL structure in shared memory.
+ *
+ * PUBLIC: int	__memp_init
+ * PUBLIC:     __P((ENV *, DB_MPOOL *, u_int, u_int32_t, u_int));
+ */
+int
+__memp_init(env, dbmp, reginfo_off, htab_buckets, max_nreg)
+	ENV *env;
+	DB_MPOOL *dbmp;
+	u_int reginfo_off, max_nreg;
+	u_int32_t htab_buckets;
+{
+	BH *frozen_bhp;
+	BH_FROZEN_ALLOC *frozen;
+	DB_ENV *dbenv;
+	DB_MPOOL_HASH *htab, *hp;
+	MPOOL *mp, *main_mp;
+	REGINFO *infop;
+	db_mutex_t mtx_base, mtx_discard, mtx_prev;
+	u_int32_t i;
+	int ret;
+	void *p;
+
+	dbenv = env->dbenv;
+
+	infop = &dbmp->reginfo[reginfo_off];
+	if ((ret = __env_alloc(infop, sizeof(MPOOL), &infop->primary)) != 0)
+		goto mem_err;
+	infop->rp->primary = R_OFFSET(infop, infop->primary);
+	mp = infop->primary;
+	memset(mp, 0, sizeof(*mp));
+
+	if ((ret =
+	    __mutex_alloc(env, MTX_MPOOL_REGION, 0, &mp->mtx_region)) != 0)
+		return (ret);
+
+	if (reginfo_off == 0) {
+		ZERO_LSN(mp->lsn);
+
+		mp->nreg = dbenv->mp_ncache;
+		mp->max_nreg = max_nreg;
+		if ((ret = __env_alloc(&dbmp->reginfo[0],
+		    max_nreg * sizeof(u_int32_t), &p)) != 0)
+			goto mem_err;
+		mp->regids = R_OFFSET(dbmp->reginfo, p);
+		mp->nbuckets = dbenv->mp_ncache * htab_buckets;
+
+		/* Allocate file table space and initialize it. */
+		if ((ret = __env_alloc(infop,
+		    MPOOL_FILE_BUCKETS * sizeof(DB_MPOOL_HASH), &htab)) != 0)
+			goto mem_err;
+		mp->ftab = R_OFFSET(infop, htab);
+		for (i = 0; i < MPOOL_FILE_BUCKETS; i++) {
+			if ((ret = __mutex_alloc(env,
+			     MTX_MPOOL_FILE_BUCKET, 0, &htab[i].mtx_hash)) != 0)
+				return (ret);
+			SH_TAILQ_INIT(&htab[i].hash_bucket);
+			atomic_init(&htab[i].hash_page_dirty, 0);
+		}
+
+		/*
+		 * Allocate all of the hash bucket mutexes up front.  We do
+		 * this so that we don't need to free and reallocate mutexes as
+		 * the cache is resized.
+		 */
+		mtx_base = mtx_prev = MUTEX_INVALID;
+		for (i = 0; i < mp->max_nreg * htab_buckets; i++) {
+			if ((ret = __mutex_alloc(env, MTX_MPOOL_HASH_BUCKET,
+			    DB_MUTEX_SHARED, &mtx_discard)) != 0)
+				return (ret);
+			if (i == 0) {
+				mtx_base = mtx_discard;
+				mtx_prev = mtx_discard - 1;
+			}
+			DB_ASSERT(env, mtx_discard == mtx_prev + 1 ||
+			    mtx_base == MUTEX_INVALID);
+			mtx_prev = mtx_discard;
+		}
+	} else {
+		main_mp = dbmp->reginfo[0].primary;
+		htab = R_ADDR(&dbmp->reginfo[0], main_mp->htab);
+		mtx_base = htab[0].mtx_hash;
+	}
+
+	/*
+	 * We preallocated all of the mutexes in a block, so for regions after
+	 * the first, we skip mutexes in use in earlier regions.  Each region
+	 * has the same number of buckets
+	 */
+	if (mtx_base != MUTEX_INVALID)
+		mtx_base += reginfo_off * htab_buckets;
+
+	/* Allocate hash table space and initialize it. */
+	if ((ret = __env_alloc(infop,
+	    htab_buckets * sizeof(DB_MPOOL_HASH), &htab)) != 0)
+		goto mem_err;
+	mp->htab = R_OFFSET(infop, htab);
+	for (i = 0; i < htab_buckets; i++) {
+		hp = &htab[i];
+		hp->mtx_hash = (mtx_base == MUTEX_INVALID) ? MUTEX_INVALID :
+		    mtx_base + i;
+		SH_TAILQ_INIT(&hp->hash_bucket);
+		atomic_init(&hp->hash_page_dirty, 0);
+#ifdef HAVE_STATISTICS
+		hp->hash_io_wait = 0;
+		hp->hash_frozen = hp->hash_thawed = hp->hash_frozen_freed = 0;
+#endif
+		hp->flags = 0;
+		ZERO_LSN(hp->old_reader);
+	}
+	mp->htab_buckets = htab_buckets;
+#ifdef HAVE_STATISTICS
+	mp->stat.st_hash_buckets = htab_buckets;
+	mp->stat.st_pagesize = dbenv->mp_pagesize == 0 ?
+	    MPOOL_DEFAULT_PAGESIZE : dbenv->mp_pagesize;
+#endif
+
+	SH_TAILQ_INIT(&mp->free_frozen);
+	SH_TAILQ_INIT(&mp->alloc_frozen);
+
+	/*
+	 * Pre-allocate one frozen buffer header.  This avoids situations where
+	 * the cache becomes full of pages and we don't even have the 28 bytes
+	 * (or so) available to allocate a frozen buffer header.
+	 */
+	if ((ret = __env_alloc(infop,
+	    sizeof(BH_FROZEN_ALLOC) + sizeof(BH_FROZEN_PAGE), &frozen)) != 0)
+		goto mem_err;
+	SH_TAILQ_INSERT_TAIL(&mp->alloc_frozen, frozen, links);
+	frozen_bhp = (BH *)(frozen + 1);
+	frozen_bhp->mtx_buf = MUTEX_INVALID;
+	SH_TAILQ_INSERT_TAIL(&mp->free_frozen, frozen_bhp, hq);
+
+	/*
+	 * Only the environment creator knows the total cache size, fill in
+	 * those statistics now.
+	 */
+	mp->stat.st_gbytes = dbenv->mp_gbytes;
+	mp->stat.st_bytes = dbenv->mp_bytes;
+	infop->mtx_alloc = mp->mtx_region;
+	return (0);
+
+mem_err:__db_errx(env, "Unable to allocate memory for mpool region");
+	return (ret);
+}
+
+/*
+ * PUBLIC: u_int32_t __memp_max_regions __P((ENV *));
+ */
+u_int32_t
+__memp_max_regions(env)
+	ENV *env;
+{
+	DB_ENV *dbenv;
+	roff_t reg_size, max_size;
+	size_t max_nreg;
+
+	dbenv = env->dbenv;
+
+	__memp_region_size(env, &reg_size, NULL);
+	max_size =
+	    (roff_t)dbenv->mp_max_gbytes * GIGABYTE + dbenv->mp_max_bytes;
+	max_nreg = (max_size + reg_size / 2) / reg_size;
+
+	/* Sanity check that the number of regions fits in 32 bits. */
+	DB_ASSERT(env, max_nreg == (u_int32_t)max_nreg);
+
+	if (max_nreg <= dbenv->mp_ncache)
+		max_nreg = dbenv->mp_ncache;
+	return ((u_int32_t)max_nreg);
+}
+
+/*
+ * __memp_region_size --
+ *	Size the region and figure out how many hash buckets we'll have.
+ */
+static void
+__memp_region_size(env, reg_sizep, htab_bucketsp)
+	ENV *env;
+	roff_t *reg_sizep;
+	u_int32_t *htab_bucketsp;
+{
+	DB_ENV *dbenv;
+	roff_t reg_size, cache_size;
+	u_int32_t pgsize;
+
+	dbenv = env->dbenv;
+
+	/*
+	 * Figure out how big each cache region is.  Cast an operand to roff_t
+	 * so we do 64-bit arithmetic as appropriate.
+	 */
+	cache_size = (roff_t)dbenv->mp_gbytes * GIGABYTE + dbenv->mp_bytes;
+	reg_size = cache_size / dbenv->mp_ncache;
+	if (reg_sizep != NULL)
+		*reg_sizep = reg_size;
+
+	/*
+	 * Figure out how many hash buckets each region will have.  Assume we
+	 * want to keep the hash chains with under 3 pages on each chain.  We
+	 * don't know the pagesize in advance, and it may differ for different
+	 * files.  Use a pagesize of 4K for the calculation -- we walk these
+	 * chains a lot, they must be kept short.  We use 2.5 as this maintains
+	 * compatibility with previous releases.
+	 *
+	 * XXX
+	 * Cache sizes larger than 10TB would cause 32-bit wrapping in the
+	 * calculation of the number of hash buckets.  This probably isn't
+	 * something we need to worry about right now, but is checked when the
+	 * cache size is set.
+	 */
+	if (htab_bucketsp != NULL) {
+		if (dbenv->mp_tablesize != 0)
+			*htab_bucketsp = __db_tablesize(dbenv->mp_tablesize);
+		else {
+			if ((pgsize = dbenv->mp_pagesize) == 0)
+				pgsize = MPOOL_DEFAULT_PAGESIZE;
+			*htab_bucketsp = __db_tablesize(
+				(u_int32_t)(reg_size / (2.5 * pgsize)));
+		}
+	}
+}
+
+/*
+ * __memp_region_mutex_count --
+ *	Return the number of mutexes the mpool region will need.
+ *
+ * PUBLIC: u_int32_t __memp_region_mutex_count __P((ENV *));
+ */
+u_int32_t
+__memp_region_mutex_count(env)
+	ENV *env;
+{
+	DB_ENV *dbenv;
+	u_int32_t htab_buckets;
+	roff_t reg_size;
+	u_int32_t num_per_cache, pgsize;
+
+	dbenv = env->dbenv;
+
+	__memp_region_size(env, &reg_size, &htab_buckets);
+	if ((pgsize = dbenv->mp_pagesize) == 0)
+		pgsize = MPOOL_DEFAULT_PAGESIZE;
+
+	/*
+	 * We need a couple of mutexes for the region itself, one for each
+	 * file handle (MPOOLFILE) the application allocates, one for each
+	 * of the MPOOL_FILE_BUCKETS, and each cache has one mutex per
+	 * hash bucket. We then need one mutex per page in the cache,
+	 * the worst case is really big if the pages are 512 bytes.
+	 */
+	num_per_cache = htab_buckets + (u_int32_t)(reg_size / pgsize);
+	return ((dbenv->mp_ncache * num_per_cache) + 50 + MPOOL_FILE_BUCKETS);
+}
+
+/*
+ * __memp_init_config --
+ *	Initialize shared configuration information.
+ */
+static int
+__memp_init_config(env, mp)
+	ENV *env;
+	MPOOL *mp;
+{
+	DB_ENV *dbenv;
+
+	dbenv = env->dbenv;
+
+	MPOOL_SYSTEM_LOCK(env);
+	if (dbenv->mp_mmapsize != 0)
+		mp->mp_mmapsize = dbenv->mp_mmapsize;
+	if (dbenv->mp_maxopenfd != 0)
+		mp->mp_maxopenfd = dbenv->mp_maxopenfd;
+	if (dbenv->mp_maxwrite != 0)
+		mp->mp_maxwrite = dbenv->mp_maxwrite;
+	if (dbenv->mp_maxwrite_sleep != 0)
+		mp->mp_maxwrite_sleep = dbenv->mp_maxwrite_sleep;
+	MPOOL_SYSTEM_UNLOCK(env);
+
+	return (0);
+}
+
+/*
+ * __memp_env_refresh --
+ *	Clean up after the mpool system on a close or failed open.
+ *
+ * PUBLIC: int __memp_env_refresh __P((ENV *));
+ */
+int
+__memp_env_refresh(env)
+	ENV *env;
+{
+	BH *bhp;
+	BH_FROZEN_ALLOC *frozen_alloc;
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	DB_MPOOL_HASH *hp;
+	DB_MPREG *mpreg;
+	MPOOL *mp, *c_mp;
+	REGINFO *infop;
+	db_mutex_t mtx_base, mtx;
+	u_int32_t bucket, htab_buckets, i, max_nreg, nreg;
+	int ret, t_ret;
+
+	ret = 0;
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	htab_buckets = mp->htab_buckets;
+	nreg = mp->nreg;
+	max_nreg = mp->max_nreg;
+	hp = R_ADDR(&dbmp->reginfo[0], mp->htab);
+	mtx_base = hp->mtx_hash;
+
+	/*
+	 * If a private region, return the memory to the heap.  Not needed for
+	 * filesystem-backed or system shared memory regions, that memory isn't
+	 * owned by any particular process.
+	 */
+	if (!F_ISSET(env, ENV_PRIVATE))
+		goto not_priv;
+
+	/* Discard buffers. */
+	for (i = 0; i < nreg; ++i) {
+		infop = &dbmp->reginfo[i];
+		c_mp = infop->primary;
+		for (hp = R_ADDR(infop, c_mp->htab), bucket = 0;
+		    bucket < c_mp->htab_buckets; ++hp, ++bucket) {
+			while ((bhp = SH_TAILQ_FIRST(
+			    &hp->hash_bucket, __bh)) != NULL)
+				if (F_ISSET(bhp, BH_FROZEN))
+					SH_TAILQ_REMOVE(
+					    &hp->hash_bucket, bhp,
+					    hq, __bh);
+				else {
+					if (F_ISSET(bhp, BH_DIRTY)) {
+						atomic_dec(env,
+						     &hp->hash_page_dirty);
+						F_CLR(bhp,
+						    BH_DIRTY | BH_DIRTY_CREATE);
+					}
+					atomic_inc(env, &bhp->ref);
+					if ((t_ret = __memp_bhfree(dbmp, infop,
+					    R_ADDR(dbmp->reginfo,
+					    bhp->mf_offset), hp, bhp,
+					    BH_FREE_FREEMEM |
+					    BH_FREE_UNLOCKED)) != 0 && ret == 0)
+						ret = t_ret;
+				}
+		}
+		MPOOL_REGION_LOCK(env, infop);
+		while ((frozen_alloc = SH_TAILQ_FIRST(
+		    &c_mp->alloc_frozen, __bh_frozen_a)) != NULL) {
+			SH_TAILQ_REMOVE(&c_mp->alloc_frozen, frozen_alloc,
+			    links, __bh_frozen_a);
+			__env_alloc_free(infop, frozen_alloc);
+		}
+		MPOOL_REGION_UNLOCK(env, infop);
+	}
+
+	/* Discard hash bucket mutexes. */
+	if (mtx_base != MUTEX_INVALID)
+		for (i = 0; i < max_nreg * htab_buckets; ++i) {
+			mtx = mtx_base + i;
+			if ((t_ret = __mutex_free(env, &mtx)) != 0 &&
+			    ret == 0)
+				ret = t_ret;
+		}
+
+not_priv:
+	/* Discard DB_MPOOLFILEs. */
+	while ((dbmfp = TAILQ_FIRST(&dbmp->dbmfq)) != NULL)
+		if ((t_ret = __memp_fclose(dbmfp, 0)) != 0 && ret == 0)
+			ret = t_ret;
+
+	/* Discard DB_MPREGs. */
+	if (dbmp->pg_inout != NULL)
+		__os_free(env, dbmp->pg_inout);
+	while ((mpreg = LIST_FIRST(&dbmp->dbregq)) != NULL) {
+		LIST_REMOVE(mpreg, q);
+		__os_free(env, mpreg);
+	}
+
+	/* Discard the DB_MPOOL thread mutex. */
+	if ((t_ret = __mutex_free(env, &dbmp->mutex)) != 0 && ret == 0)
+		ret = t_ret;
+
+	if (F_ISSET(env, ENV_PRIVATE)) {
+		/* Discard REGION IDs. */
+		infop = &dbmp->reginfo[0];
+		infop->mtx_alloc = MUTEX_INVALID;
+		__memp_free(infop, R_ADDR(infop, mp->regids));
+
+		/* Discard the File table. */
+		__memp_free(infop, R_ADDR(infop, mp->ftab));
+
+		/* Discard Hash tables. */
+		for (i = 0; i < nreg; ++i) {
+			infop = &dbmp->reginfo[i];
+			c_mp = infop->primary;
+			infop->mtx_alloc = MUTEX_INVALID;
+			__memp_free(infop, R_ADDR(infop, c_mp->htab));
+		}
+	}
+
+	/* Detach from the region. */
+	for (i = 0; i < nreg; ++i) {
+		infop = &dbmp->reginfo[i];
+		if ((t_ret =
+		    __env_region_detach(env, infop, 0)) != 0 && ret == 0)
+			ret = t_ret;
+	}
+
+	/* Discard DB_MPOOL. */
+	__os_free(env, dbmp->reginfo);
+	__os_free(env, dbmp);
+
+	env->mp_handle = NULL;
+	return (ret);
+}
diff --git a/mp/mp_register.c b/mp/mp_register.c
new file mode 100644
index 0000000..1ed907b
--- /dev/null
+++ b/mp/mp_register.c
@@ -0,0 +1,115 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+
+/*
+ * memp_register_pp --
+ *	ENV->memp_register pre/post processing.
+ *
+ * PUBLIC: int __memp_register_pp __P((DB_ENV *, int,
+ * PUBLIC:     int (*)(DB_ENV *, db_pgno_t, void *, DBT *),
+ * PUBLIC:     int (*)(DB_ENV *, db_pgno_t, void *, DBT *)));
+ */
+int
+__memp_register_pp(dbenv, ftype, pgin, pgout)
+	DB_ENV *dbenv;
+	int ftype;
+	int (*pgin) __P((DB_ENV *, db_pgno_t, void *, DBT *));
+	int (*pgout) __P((DB_ENV *, db_pgno_t, void *, DBT *));
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "DB_ENV->memp_register", DB_INIT_MPOOL);
+
+	if (REP_ON(env)) {
+		__db_errx(env, "%s%s", "DB_ENV->memp_register: ",
+		    "method not permitted when replication is configured");
+		return (EINVAL);
+	}
+
+	ENV_ENTER(env, ip);
+	ret = __memp_register(env, ftype, pgin, pgout);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * memp_register --
+ *	ENV->memp_register.
+ *
+ * PUBLIC: int __memp_register __P((ENV *, int,
+ * PUBLIC:     int (*)(DB_ENV *, db_pgno_t, void *, DBT *),
+ * PUBLIC:     int (*)(DB_ENV *, db_pgno_t, void *, DBT *)));
+ */
+int
+__memp_register(env, ftype, pgin, pgout)
+	ENV *env;
+	int ftype;
+	int (*pgin) __P((DB_ENV *, db_pgno_t, void *, DBT *));
+	int (*pgout) __P((DB_ENV *, db_pgno_t, void *, DBT *));
+{
+	DB_MPOOL *dbmp;
+	DB_MPREG *mpreg;
+	int ret;
+
+	dbmp = env->mp_handle;
+
+	/*
+	 * We keep the DB pgin/pgout functions outside of the linked list
+	 * to avoid locking/unlocking the linked list on every page I/O.
+	 *
+	 * The Berkeley DB I/O conversion functions are registered when the
+	 * environment is first created, so there's no need for locking here.
+	 */
+	if (ftype == DB_FTYPE_SET) {
+		if (dbmp->pg_inout != NULL)
+			return (0);
+		if ((ret =
+		    __os_malloc(env, sizeof(DB_MPREG), &dbmp->pg_inout)) != 0)
+			return (ret);
+		dbmp->pg_inout->ftype = ftype;
+		dbmp->pg_inout->pgin = pgin;
+		dbmp->pg_inout->pgout = pgout;
+		return (0);
+	}
+
+	/*
+	 * The item may already have been registered.  If already registered,
+	 * just update the entry, although it's probably unchanged.
+	 */
+	MUTEX_LOCK(env, dbmp->mutex);
+	LIST_FOREACH(mpreg, &dbmp->dbregq, q)
+		if (mpreg->ftype == ftype) {
+			mpreg->pgin = pgin;
+			mpreg->pgout = pgout;
+			break;
+		}
+
+	if (mpreg == NULL) {			/* New entry. */
+		if ((ret = __os_malloc(env, sizeof(DB_MPREG), &mpreg)) != 0)
+			return (ret);
+		mpreg->ftype = ftype;
+		mpreg->pgin = pgin;
+		mpreg->pgout = pgout;
+
+		LIST_INSERT_HEAD(&dbmp->dbregq, mpreg, q);
+	}
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	return (0);
+}
diff --git a/mp/mp_resize.c b/mp/mp_resize.c
new file mode 100644
index 0000000..a234ad7
--- /dev/null
+++ b/mp/mp_resize.c
@@ -0,0 +1,579 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 2006-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+static int __memp_add_bucket __P((DB_MPOOL *));
+static int __memp_add_region __P((DB_MPOOL *));
+static int __memp_map_regions __P((DB_MPOOL *));
+static int __memp_merge_buckets
+    __P((DB_MPOOL *, u_int32_t, u_int32_t, u_int32_t));
+static int __memp_remove_bucket __P((DB_MPOOL *));
+static int __memp_remove_region __P((DB_MPOOL *));
+
+/*
+ * PUBLIC: int __memp_get_bucket __P((ENV *, MPOOLFILE *,
+ * PUBLIC:     db_pgno_t, REGINFO **, DB_MPOOL_HASH **, u_int32_t *));
+ */
+int
+__memp_get_bucket(env, mfp, pgno, infopp, hpp, bucketp)
+	ENV *env;
+	MPOOLFILE *mfp;
+	db_pgno_t pgno;
+	REGINFO **infopp;
+	DB_MPOOL_HASH **hpp;
+	u_int32_t *bucketp;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *c_mp, *mp;
+	REGINFO *infop;
+	roff_t mf_offset;
+	u_int32_t bucket, nbuckets, new_bucket, new_nbuckets, region;
+	u_int32_t *regids;
+	int ret;
+
+	dbmp = env->mp_handle;
+	mf_offset = R_OFFSET(dbmp->reginfo, mfp);
+	mp = dbmp->reginfo[0].primary;
+	ret = 0;
+
+	for (;;) {
+		nbuckets = mp->nbuckets;
+		MP_BUCKET(mf_offset, pgno, nbuckets, bucket);
+
+		/*
+		 * Once we work out which region we are looking in, we have to
+		 * check that we have that region mapped, and that the version
+		 * we have matches the ID in the main mpool region.  Otherwise
+		 * we have to go and map in any regions that don't match and
+		 * retry.
+		 */
+		region = NREGION(mp, bucket);
+		regids = R_ADDR(dbmp->reginfo, mp->regids);
+
+		for (;;) {
+			infop = *infopp = &dbmp->reginfo[region];
+			c_mp = infop->primary;
+
+			/* If we have the correct region mapped, we're done. */
+			if (c_mp != NULL && regids[region] == infop->id)
+				break;
+			if ((ret = __memp_map_regions(dbmp)) != 0)
+				return (ret);
+		}
+
+		/* If our caller wants the hash bucket, lock it here. */
+		if (hpp != NULL) {
+			hp = R_ADDR(infop, c_mp->htab);
+			hp = &hp[bucket - region * mp->htab_buckets];
+
+			MUTEX_READLOCK(env, hp->mtx_hash);
+
+			/*
+			 * Check that we still have the correct region mapped.
+			 */
+			if (regids[region] != infop->id) {
+				MUTEX_UNLOCK(env, hp->mtx_hash);
+				continue;
+			}
+
+			/*
+			 * Now that the bucket is locked, we need to check that
+			 * the cache has not been resized while we waited.
+			 */
+			new_nbuckets = mp->nbuckets;
+			if (nbuckets != new_nbuckets) {
+				MP_BUCKET(mf_offset, pgno, new_nbuckets,
+				    new_bucket);
+
+				if (new_bucket != bucket) {
+					MUTEX_UNLOCK(env, hp->mtx_hash);
+					continue;
+				}
+			}
+
+			*hpp = hp;
+		}
+
+		break;
+	}
+
+	if (bucketp != NULL)
+		*bucketp = bucket - region * mp->htab_buckets;
+	return (ret);
+}
+
+static int
+__memp_merge_buckets(dbmp, new_nbuckets, old_bucket, new_bucket)
+	DB_MPOOL *dbmp;
+	u_int32_t new_nbuckets, old_bucket, new_bucket;
+{
+	BH *alloc_bhp, *bhp, *current_bhp, *new_bhp, *next_bhp;
+	DB_LSN vlsn;
+	DB_MPOOL_HASH *new_hp, *old_hp;
+	ENV *env;
+	MPOOL *mp, *new_mp, *old_mp;
+	MPOOLFILE *mfp;
+	REGINFO *new_infop, *old_infop;
+	u_int32_t bucket, high_mask, new_region, old_region;
+	int ret;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	new_bhp = NULL;
+	ret = 0;
+
+	MP_MASK(new_nbuckets, high_mask);
+
+	old_region = NREGION(mp, old_bucket);
+	old_infop = &dbmp->reginfo[old_region];
+	old_mp = old_infop->primary;
+	old_hp = R_ADDR(old_infop, old_mp->htab);
+	old_hp = &old_hp[old_bucket - old_region * mp->htab_buckets];
+
+	new_region = NREGION(mp, new_bucket);
+	new_infop = &dbmp->reginfo[new_region];
+	new_mp = new_infop->primary;
+	new_hp = R_ADDR(new_infop, new_mp->htab);
+	new_hp = &new_hp[new_bucket - new_region * mp->htab_buckets];
+
+	/*
+	 * Before merging, we need to check that there are no old buffers left
+	 * in the target hash bucket after a previous split.
+	 */
+free_old:
+	MUTEX_LOCK(env, new_hp->mtx_hash);
+	SH_TAILQ_FOREACH(bhp, &new_hp->hash_bucket, hq, __bh) {
+		MP_BUCKET(bhp->mf_offset, bhp->pgno, mp->nbuckets, bucket);
+
+		if (bucket != new_bucket) {
+			/*
+			 * There is no way that an old buffer can be locked
+			 * after a split, since everyone will look for it in
+			 * the new hash bucket.
+			 */
+			DB_ASSERT(env, !F_ISSET(bhp, BH_DIRTY) &&
+			    atomic_read(&bhp->ref) == 0);
+			atomic_inc(env, &bhp->ref);
+			mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+			if ((ret = __memp_bhfree(dbmp, new_infop,
+			    mfp, new_hp, bhp, BH_FREE_FREEMEM)) != 0) {
+				MUTEX_UNLOCK(env, new_hp->mtx_hash);
+				return (ret);
+			}
+
+			/*
+			 * The free has modified the list of buffers and
+			 * dropped the mutex.  We need to start again.
+			 */
+			goto free_old;
+		}
+	}
+	MUTEX_UNLOCK(env, new_hp->mtx_hash);
+
+	/*
+	 * Before we begin, make sure that all of the buffers we care about are
+	 * not in use and not frozen.  We do this because we can't drop the old
+	 * hash bucket mutex once we start moving buffers around.
+	 */
+retry:	MUTEX_LOCK(env, old_hp->mtx_hash);
+	SH_TAILQ_FOREACH(bhp, &old_hp->hash_bucket, hq, __bh) {
+		MP_HASH_BUCKET(MP_HASH(bhp->mf_offset, bhp->pgno),
+		    new_nbuckets, high_mask, bucket);
+
+		if (bucket == new_bucket && atomic_read(&bhp->ref) != 0) {
+			MUTEX_UNLOCK(env, old_hp->mtx_hash);
+			__os_yield(env, 0, 0);
+			goto retry;
+		} else if (bucket == new_bucket && F_ISSET(bhp, BH_FROZEN)) {
+			atomic_inc(env, &bhp->ref);
+			/*
+			 * We need to drop the hash bucket mutex to avoid
+			 * self-blocking when we allocate a new buffer.
+			 */
+			MUTEX_UNLOCK(env, old_hp->mtx_hash);
+			MUTEX_LOCK(env, bhp->mtx_buf);
+			F_SET(bhp, BH_EXCLUSIVE);
+			if (BH_OBSOLETE(bhp, old_hp->old_reader, vlsn))
+				alloc_bhp = NULL;
+			else {
+				mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+				if ((ret = __memp_alloc(dbmp,
+				    old_infop, mfp, 0, NULL, &alloc_bhp)) != 0)
+					goto err;
+			}
+			/*
+			 * But we need to lock the hash bucket again before
+			 * thawing the buffer.  The call to __memp_bh_thaw
+			 * will unlock the hash bucket mutex.
+			 */
+			MUTEX_LOCK(env, old_hp->mtx_hash);
+			if (F_ISSET(bhp, BH_THAWED)) {
+				ret = __memp_bhfree(dbmp, old_infop, NULL, NULL,
+				    alloc_bhp,
+				    BH_FREE_FREEMEM | BH_FREE_UNLOCKED);
+			} else
+				ret = __memp_bh_thaw(dbmp,
+				    old_infop, old_hp, bhp, alloc_bhp);
+
+			/*
+			 * We've dropped the mutex in order to thaw, so we need
+			 * to go back to the beginning and check that all of
+			 * the buffers we care about are still unlocked and
+			 * unreferenced.
+			 */
+err:			atomic_dec(env, &bhp->ref);
+			F_CLR(bhp, BH_EXCLUSIVE);
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			if (ret != 0)
+				return (ret);
+			goto retry;
+		}
+	}
+
+	/*
+	 * We now know that all of the buffers we care about are unlocked and
+	 * unreferenced.  Go ahead and copy them.
+	 */
+	SH_TAILQ_FOREACH(bhp, &old_hp->hash_bucket, hq, __bh) {
+		MP_HASH_BUCKET(MP_HASH(bhp->mf_offset, bhp->pgno),
+		    new_nbuckets, high_mask, bucket);
+		mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+
+		/*
+		 * We ignore buffers that don't hash to the new bucket.  We
+		 * could also ignore clean buffers which are not part of a
+		 * multiversion chain as long as they have a backing file.
+		 */
+		if (bucket != new_bucket || (!F_ISSET(bhp, BH_DIRTY) &&
+		    SH_CHAIN_SINGLETON(bhp, vc) && !mfp->no_backing_file))
+			continue;
+
+		for (current_bhp = bhp, next_bhp = NULL;
+		    current_bhp != NULL;
+		    current_bhp = SH_CHAIN_PREV(current_bhp, vc, __bh),
+		    next_bhp = alloc_bhp) {
+			/* Allocate in the new region. */
+			if ((ret = __memp_alloc(dbmp,
+			    new_infop, mfp, 0, NULL, &alloc_bhp)) != 0)
+				break;
+
+			alloc_bhp->ref = current_bhp->ref;
+			alloc_bhp->priority = current_bhp->priority;
+			alloc_bhp->pgno = current_bhp->pgno;
+			alloc_bhp->mf_offset = current_bhp->mf_offset;
+			alloc_bhp->flags = current_bhp->flags;
+			alloc_bhp->td_off = current_bhp->td_off;
+
+			/*
+			 * We've duplicated the buffer, so now we need to
+			 * update reference counts, including the counts in the
+			 * per-MPOOLFILE and the transaction detail (for MVCC
+			 * buffers).
+			 */
+			MUTEX_LOCK(env, mfp->mutex);
+			++mfp->block_cnt;
+			MUTEX_UNLOCK(env, mfp->mutex);
+
+			if (alloc_bhp->td_off != INVALID_ROFF &&
+			    (ret = __txn_add_buffer(env,
+			    R_ADDR(&env->tx_handle->reginfo,
+			    alloc_bhp->td_off))) != 0)
+				break;
+
+			memcpy(alloc_bhp->buf, bhp->buf, mfp->stat.st_pagesize);
+
+			/*
+			 * We build up the MVCC chain first, then insert the
+			 * head (stored in new_bhp) once.
+			 */
+			if (next_bhp == NULL) {
+				SH_CHAIN_INIT(alloc_bhp, vc);
+				new_bhp = alloc_bhp;
+			} else
+				SH_CHAIN_INSERT_BEFORE(
+				    next_bhp, alloc_bhp, vc, __bh);
+		}
+
+		MUTEX_LOCK(env, new_hp->mtx_hash);
+		SH_TAILQ_INSERT_TAIL(&new_hp->hash_bucket, new_bhp, hq);
+		if (F_ISSET(new_bhp, BH_DIRTY))
+			atomic_inc(env, &new_hp->hash_page_dirty);
+
+		if (F_ISSET(bhp, BH_DIRTY)) {
+			F_CLR(bhp, BH_DIRTY);
+			atomic_dec(env, &old_hp->hash_page_dirty);
+		}
+		MUTEX_UNLOCK(env, new_hp->mtx_hash);
+	}
+
+	if (ret == 0)
+		mp->nbuckets = new_nbuckets;
+	MUTEX_UNLOCK(env, old_hp->mtx_hash);
+
+	return (ret);
+}
+
+static int
+__memp_add_bucket(dbmp)
+	DB_MPOOL *dbmp;
+{
+	ENV *env;
+	MPOOL *mp;
+	u_int32_t high_mask, new_bucket, old_bucket;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+
+	new_bucket = mp->nbuckets;
+	/* We should always be adding buckets to the last region. */
+	DB_ASSERT(env, NREGION(mp, new_bucket) == mp->nreg - 1);
+	MP_MASK(mp->nbuckets, high_mask);
+	old_bucket = new_bucket & (high_mask >> 1);
+
+	/*
+	 * With fixed-sized regions, the new region is always smaller than the
+	 * existing total cache size, so buffers always need to be copied.  If
+	 * we implement variable region sizes, it's possible that we will be
+	 * splitting a hash bucket in the new region.  Catch that here.
+	 */
+	DB_ASSERT(env, NREGION(mp, old_bucket) != NREGION(mp, new_bucket));
+
+	return (__memp_merge_buckets(dbmp, mp->nbuckets + 1,
+	    old_bucket, new_bucket));
+}
+
+static int
+__memp_add_region(dbmp)
+	DB_MPOOL *dbmp;
+{
+	ENV *env;
+	MPOOL *mp;
+	REGINFO *infop;
+	int ret;
+	roff_t reg_size;
+	u_int i;
+	u_int32_t *regids;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	/* All cache regions are the same size. */
+	reg_size = dbmp->reginfo[0].rp->size;
+	ret = 0;
+
+	infop = &dbmp->reginfo[mp->nreg];
+	infop->env = env;
+	infop->type = REGION_TYPE_MPOOL;
+	infop->id = INVALID_REGION_ID;
+	infop->flags = REGION_CREATE_OK;
+	if ((ret = __env_region_attach(env, infop, reg_size)) != 0)
+		return (ret);
+	if ((ret = __memp_init(env,
+	    dbmp, mp->nreg, mp->htab_buckets, mp->max_nreg)) != 0)
+		return (ret);
+	regids = R_ADDR(dbmp->reginfo, mp->regids);
+	regids[mp->nreg++] = infop->id;
+
+	for (i = 0; i < mp->htab_buckets; i++)
+		if ((ret = __memp_add_bucket(dbmp)) != 0)
+			break;
+
+	return (ret);
+}
+
+static int
+__memp_remove_bucket(dbmp)
+	DB_MPOOL *dbmp;
+{
+	ENV *env;
+	MPOOL *mp;
+	u_int32_t high_mask, new_bucket, old_bucket;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+
+	old_bucket = mp->nbuckets - 1;
+
+	/* We should always be removing buckets from the last region. */
+	DB_ASSERT(env, NREGION(mp, old_bucket) == mp->nreg - 1);
+	MP_MASK(mp->nbuckets - 1, high_mask);
+	new_bucket = old_bucket & (high_mask >> 1);
+
+	return (__memp_merge_buckets(dbmp, mp->nbuckets - 1,
+	    old_bucket, new_bucket));
+}
+
+static int
+__memp_remove_region(dbmp)
+	DB_MPOOL *dbmp;
+{
+	ENV *env;
+	MPOOL *mp;
+	REGINFO *infop;
+	int ret;
+	u_int i;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	ret = 0;
+
+	if (mp->nreg == 1) {
+		__db_errx(env, "cannot remove the last cache");
+		return (EINVAL);
+	}
+
+	for (i = 0; i < mp->htab_buckets; i++)
+		if ((ret = __memp_remove_bucket(dbmp)) != 0)
+			return (ret);
+
+	/* Detach from the region then destroy it. */
+	infop = &dbmp->reginfo[--mp->nreg];
+	return (__env_region_detach(env, infop, 1));
+}
+
+static int
+__memp_map_regions(dbmp)
+	DB_MPOOL *dbmp;
+{
+	ENV *env;
+	MPOOL *mp;
+	int ret;
+	u_int i;
+	u_int32_t *regids;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	regids = R_ADDR(dbmp->reginfo, mp->regids);
+	ret = 0;
+
+	for (i = 1; i < mp->nreg; ++i) {
+		if (dbmp->reginfo[i].primary != NULL &&
+		    dbmp->reginfo[i].id == regids[i])
+			continue;
+
+		if (dbmp->reginfo[i].primary != NULL)
+			ret = __env_region_detach(env, &dbmp->reginfo[i], 0);
+
+		dbmp->reginfo[i].env = env;
+		dbmp->reginfo[i].type = REGION_TYPE_MPOOL;
+		dbmp->reginfo[i].id = regids[i];
+		dbmp->reginfo[i].flags = REGION_JOIN_OK;
+		if ((ret =
+		    __env_region_attach(env, &dbmp->reginfo[i], 0)) != 0)
+			return (ret);
+		dbmp->reginfo[i].primary = R_ADDR(&dbmp->reginfo[i],
+		    dbmp->reginfo[i].rp->primary);
+	}
+
+	for (; i < mp->max_nreg; i++)
+		if (dbmp->reginfo[i].primary != NULL &&
+		    (ret = __env_region_detach(env,
+		    &dbmp->reginfo[i], 0)) != 0)
+			break;
+
+	return (ret);
+}
+
+/*
+ * PUBLIC: int __memp_resize __P((DB_MPOOL *, u_int32_t, u_int32_t));
+ */
+int
+__memp_resize(dbmp, gbytes, bytes)
+	DB_MPOOL *dbmp;
+	u_int32_t gbytes, bytes;
+{
+	ENV *env;
+	MPOOL *mp;
+	int ret;
+	u_int32_t ncache;
+	roff_t reg_size, total_size;
+
+	env = dbmp->env;
+	mp = dbmp->reginfo[0].primary;
+	reg_size = dbmp->reginfo[0].rp->size;
+	total_size = (roff_t)gbytes * GIGABYTE + bytes;
+	ncache = (u_int32_t)((total_size + reg_size / 2) / reg_size);
+
+	if (ncache < 1)
+		ncache = 1;
+	else if (ncache > mp->max_nreg) {
+		__db_errx(env,
+		    "cannot resize to %lu cache regions: maximum is %lu",
+		    (u_long)ncache, (u_long)mp->max_nreg);
+		return (EINVAL);
+	}
+
+	ret = 0;
+	MUTEX_LOCK(env, mp->mtx_resize);
+	while (mp->nreg != ncache)
+		if ((ret = (mp->nreg < ncache ?
+		    __memp_add_region(dbmp) :
+		    __memp_remove_region(dbmp))) != 0)
+			break;
+	MUTEX_UNLOCK(env, mp->mtx_resize);
+
+	return (ret);
+}
+
+/*
+ * PUBLIC: int __memp_get_cache_max __P((DB_ENV *, u_int32_t *, u_int32_t *));
+ */
+int
+__memp_get_cache_max(dbenv, max_gbytesp, max_bytesp)
+	DB_ENV *dbenv;
+	u_int32_t *max_gbytesp, *max_bytesp;
+{
+	DB_MPOOL *dbmp;
+	ENV *env;
+	MPOOL *mp;
+	roff_t reg_size, max_size;
+
+	env = dbenv->env;
+
+	ENV_NOT_CONFIGURED(env,
+	    env->mp_handle, "DB_ENV->get_mp_max_ncache", DB_INIT_MPOOL);
+
+	if (MPOOL_ON(env)) {
+		/* Cannot be set after open, no lock required to read. */
+		dbmp = env->mp_handle;
+		mp = dbmp->reginfo[0].primary;
+		reg_size = dbmp->reginfo[0].rp->size;
+		max_size = mp->max_nreg * reg_size;
+		*max_gbytesp = (u_int32_t)(max_size / GIGABYTE);
+		*max_bytesp = (u_int32_t)(max_size % GIGABYTE);
+	} else {
+		*max_gbytesp = dbenv->mp_max_gbytes;
+		*max_bytesp = dbenv->mp_max_bytes;
+	}
+
+	return (0);
+}
+
+/*
+ * PUBLIC: int __memp_set_cache_max __P((DB_ENV *, u_int32_t, u_int32_t));
+ */
+int
+__memp_set_cache_max(dbenv, max_gbytes, max_bytes)
+	DB_ENV *dbenv;
+	u_int32_t max_gbytes, max_bytes;
+{
+	ENV *env;
+
+	env = dbenv->env;
+
+	ENV_ILLEGAL_AFTER_OPEN(env, "DB_ENV->set_cache_max");
+	dbenv->mp_max_gbytes = max_gbytes;
+	dbenv->mp_max_bytes = max_bytes;
+
+	return (0);
+}
diff --git a/mp/mp_stat.c b/mp/mp_stat.c
new file mode 100644
index 0000000..32f8080
--- /dev/null
+++ b/mp/mp_stat.c
@@ -0,0 +1,904 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/db_page.h"
+#include "dbinc/db_am.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/txn.h"
+
+#ifdef HAVE_STATISTICS
+static void __memp_print_bh __P((ENV *,
+		DB_MPOOL *, const char *, BH *, roff_t *));
+static int  __memp_print_all __P((ENV *, u_int32_t));
+static int  __memp_print_stats __P((ENV *, u_int32_t));
+static int __memp_print_hash __P((ENV *,
+		DB_MPOOL *, REGINFO *, roff_t *, u_int32_t));
+static int  __memp_stat __P((ENV *,
+		DB_MPOOL_STAT **, DB_MPOOL_FSTAT ***, u_int32_t));
+static void __memp_stat_wait
+		__P((ENV *, REGINFO *, MPOOL *, DB_MPOOL_STAT *, u_int32_t));
+static int __memp_file_stats __P((ENV *,
+		MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+static int __memp_count_files __P((ENV *,
+		MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+static int __memp_get_files __P((ENV *,
+		MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+static int __memp_print_files __P((ENV *,
+		MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+
+/*
+ * __memp_stat_pp --
+ *	DB_ENV->memp_stat pre/post processing.
+ *
+ * PUBLIC: int __memp_stat_pp
+ * PUBLIC:     __P((DB_ENV *, DB_MPOOL_STAT **, DB_MPOOL_FSTAT ***, u_int32_t));
+ */
+int
+__memp_stat_pp(dbenv, gspp, fspp, flags)
+	DB_ENV *dbenv;
+	DB_MPOOL_STAT **gspp;
+	DB_MPOOL_FSTAT ***fspp;
+	u_int32_t flags;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "DB_ENV->memp_stat", DB_INIT_MPOOL);
+
+	if ((ret = __db_fchk(env,
+	    "DB_ENV->memp_stat", flags, DB_STAT_CLEAR)) != 0)
+		return (ret);
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_stat(env, gspp, fspp, flags)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_stat --
+ *	ENV->memp_stat
+ */
+static int
+__memp_stat(env, gspp, fspp, flags)
+	ENV *env;
+	DB_MPOOL_STAT **gspp;
+	DB_MPOOL_FSTAT ***fspp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_FSTAT **tfsp;
+	DB_MPOOL_STAT *sp;
+	MPOOL *c_mp, *mp;
+	size_t len;
+	int ret;
+	u_int32_t i, st_bytes, st_gbytes, st_hash_buckets, st_pages;
+	uintmax_t tmp_wait, tmp_nowait;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+
+	/* Global statistics. */
+	if (gspp != NULL) {
+		*gspp = NULL;
+
+		if ((ret = __os_umalloc(env, sizeof(**gspp), gspp)) != 0)
+			return (ret);
+		memset(*gspp, 0, sizeof(**gspp));
+		sp = *gspp;
+
+		/*
+		 * Initialization and information that is not maintained on
+		 * a per-cache basis.  Note that configuration information
+		 * may be modified at any time, and so we have to lock.
+		 */
+		sp->st_gbytes = mp->stat.st_gbytes;
+		sp->st_bytes = mp->stat.st_bytes;
+		sp->st_pagesize = mp->stat.st_pagesize;
+		sp->st_ncache = mp->nreg;
+		sp->st_max_ncache = mp->max_nreg;
+		sp->st_regsize = dbmp->reginfo[0].rp->size;
+		sp->st_sync_interrupted = mp->stat.st_sync_interrupted;
+
+		MPOOL_SYSTEM_LOCK(env);
+		sp->st_mmapsize = mp->mp_mmapsize;
+		sp->st_maxopenfd = mp->mp_maxopenfd;
+		sp->st_maxwrite = mp->mp_maxwrite;
+		sp->st_maxwrite_sleep = mp->mp_maxwrite_sleep;
+		MPOOL_SYSTEM_UNLOCK(env);
+
+		/* Walk the cache list and accumulate the global information. */
+		for (i = 0; i < mp->nreg; ++i) {
+			c_mp = dbmp->reginfo[i].primary;
+
+			sp->st_map += c_mp->stat.st_map;
+			sp->st_cache_hit += c_mp->stat.st_cache_hit;
+			sp->st_cache_miss += c_mp->stat.st_cache_miss;
+			sp->st_page_create += c_mp->stat.st_page_create;
+			sp->st_page_in += c_mp->stat.st_page_in;
+			sp->st_page_out += c_mp->stat.st_page_out;
+			sp->st_ro_evict += c_mp->stat.st_ro_evict;
+			sp->st_rw_evict += c_mp->stat.st_rw_evict;
+			sp->st_page_trickle += c_mp->stat.st_page_trickle;
+			sp->st_pages += c_mp->stat.st_pages;
+			/*
+			 * st_page_dirty	calculated by __memp_stat_hash
+			 * st_page_clean	calculated here
+			 */
+			__memp_stat_hash(
+			    &dbmp->reginfo[i], c_mp, &sp->st_page_dirty);
+			sp->st_page_clean = sp->st_pages - sp->st_page_dirty;
+			sp->st_hash_buckets += c_mp->stat.st_hash_buckets;
+			sp->st_hash_searches += c_mp->stat.st_hash_searches;
+			sp->st_hash_longest += c_mp->stat.st_hash_longest;
+			sp->st_hash_examined += c_mp->stat.st_hash_examined;
+			/*
+			 * st_hash_nowait	calculated by __memp_stat_wait
+			 * st_hash_wait
+			 */
+			__memp_stat_wait(
+			    env, &dbmp->reginfo[i], c_mp, sp, flags);
+			__mutex_set_wait_info(env,
+			    c_mp->mtx_region, &tmp_wait, &tmp_nowait);
+			sp->st_region_nowait += tmp_nowait;
+			sp->st_region_wait += tmp_wait;
+			sp->st_alloc += c_mp->stat.st_alloc;
+			sp->st_alloc_buckets += c_mp->stat.st_alloc_buckets;
+			if (sp->st_alloc_max_buckets <
+			    c_mp->stat.st_alloc_max_buckets)
+				sp->st_alloc_max_buckets =
+				    c_mp->stat.st_alloc_max_buckets;
+			sp->st_alloc_pages += c_mp->stat.st_alloc_pages;
+			if (sp->st_alloc_max_pages <
+			    c_mp->stat.st_alloc_max_pages)
+				sp->st_alloc_max_pages =
+				    c_mp->stat.st_alloc_max_pages;
+
+			if (LF_ISSET(DB_STAT_CLEAR)) {
+				if (!LF_ISSET(DB_STAT_SUBSYSTEM))
+					__mutex_clear(env, c_mp->mtx_region);
+
+				MPOOL_SYSTEM_LOCK(env);
+				st_bytes = c_mp->stat.st_bytes;
+				st_gbytes = c_mp->stat.st_gbytes;
+				st_hash_buckets = c_mp->stat.st_hash_buckets;
+				st_pages = c_mp->stat.st_pages;
+				memset(&c_mp->stat, 0, sizeof(c_mp->stat));
+				c_mp->stat.st_bytes = st_bytes;
+				c_mp->stat.st_gbytes = st_gbytes;
+				c_mp->stat.st_hash_buckets = st_hash_buckets;
+				c_mp->stat.st_pages = st_pages;
+				MPOOL_SYSTEM_UNLOCK(env);
+			}
+		}
+
+		/*
+		 * We have duplicate statistics fields in per-file structures
+		 * and the cache.  The counters are only incremented in the
+		 * per-file structures, except if a file is flushed from the
+		 * mpool, at which time we copy its information into the cache
+		 * statistics.  We added the cache information above, now we
+		 * add the per-file information.
+		 */
+		if ((ret = __memp_walk_files(env, mp, __memp_file_stats,
+		    sp, NULL, fspp == NULL ? LF_ISSET(DB_STAT_CLEAR) : 0)) != 0)
+			return (ret);
+	}
+
+	/* Per-file statistics. */
+	if (fspp != NULL) {
+		*fspp = NULL;
+
+		/* Count the MPOOLFILE structures. */
+		i = 0;
+		len = 0;
+		if ((ret = __memp_walk_files(env,
+		     mp, __memp_count_files, &len, &i, flags)) != 0)
+			return (ret);
+
+		if (i == 0)
+			return (0);
+		len += sizeof(DB_MPOOL_FSTAT *);	/* Trailing NULL */
+
+		/* Allocate space */
+		if ((ret = __os_umalloc(env, len, fspp)) != 0)
+			return (ret);
+
+		tfsp = *fspp;
+		*tfsp = NULL;
+
+		/*
+		 * Files may have been opened since we counted, don't walk
+		 * off the end of the allocated space.
+		 */
+		if ((ret = __memp_walk_files(env,
+		    mp, __memp_get_files, &tfsp, &i, flags)) != 0)
+			return (ret);
+
+		*++tfsp = NULL;
+	}
+
+	return (0);
+}
+
+static int
+__memp_file_stats(env, mfp, argp, countp, flags)
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *argp;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	DB_MPOOL_STAT *sp;
+	u_int32_t pagesize;
+
+	COMPQUIET(env, NULL);
+	COMPQUIET(countp, NULL);
+
+	sp = argp;
+
+	sp->st_map += mfp->stat.st_map;
+	sp->st_cache_hit += mfp->stat.st_cache_hit;
+	sp->st_cache_miss += mfp->stat.st_cache_miss;
+	sp->st_page_create += mfp->stat.st_page_create;
+	sp->st_page_in += mfp->stat.st_page_in;
+	sp->st_page_out += mfp->stat.st_page_out;
+	if (LF_ISSET(DB_STAT_CLEAR)) {
+		pagesize = mfp->stat.st_pagesize;
+		memset(&mfp->stat, 0, sizeof(mfp->stat));
+		mfp->stat.st_pagesize = pagesize;
+	}
+	return (0);
+}
+
+static int
+__memp_count_files(env, mfp, argp, countp, flags)
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *argp;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	size_t len;
+
+	COMPQUIET(flags, 0);
+	dbmp = env->mp_handle;
+	len = *(size_t *)argp;
+
+	(*countp)++;
+	len += sizeof(DB_MPOOL_FSTAT *) +
+	    sizeof(DB_MPOOL_FSTAT) + strlen(__memp_fns(dbmp, mfp)) + 1;
+
+	*(size_t *)argp = len;
+	return (0);
+}
+
+/*
+ * __memp_get_files --
+ *	get file specific statistics
+ *
+ * Build each individual entry.  We assume that an array of pointers are
+ * aligned correctly to be followed by an array of structures, which should
+ * be safe (in this particular case, the first element of the structure
+ * is a pointer, so we're doubly safe).  The array is followed by space
+ * for the text file names.
+ */
+static int
+__memp_get_files(env, mfp, argp, countp, flags)
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *argp;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_FSTAT **tfsp, *tstruct;
+	char *name, *tname;
+	size_t nlen;
+	u_int32_t pagesize;
+
+	if (*countp == 0)
+		return (0);
+
+	dbmp = env->mp_handle;
+	tfsp = *(DB_MPOOL_FSTAT ***)argp;
+
+	if (*tfsp == NULL) {
+		/* Add 1 to count because we need to skip over the NULL. */
+		tstruct = (DB_MPOOL_FSTAT *)(tfsp + *countp + 1);
+		tname = (char *)(tstruct + *countp);
+		*tfsp = tstruct;
+	} else {
+		tstruct = *tfsp + 1;
+		tname = (*tfsp)->file_name + strlen((*tfsp)->file_name) + 1;
+		*++tfsp = tstruct;
+	}
+
+	name = __memp_fns(dbmp, mfp);
+	nlen = strlen(name) + 1;
+	memcpy(tname, name, nlen);
+	*tstruct = mfp->stat;
+	tstruct->file_name = tname;
+
+	*(DB_MPOOL_FSTAT ***)argp = tfsp;
+	(*countp)--;
+
+	if (LF_ISSET(DB_STAT_CLEAR)) {
+		pagesize = mfp->stat.st_pagesize;
+		memset(&mfp->stat, 0, sizeof(mfp->stat));
+		mfp->stat.st_pagesize = pagesize;
+	}
+	return (0);
+}
+
+/*
+ * __memp_stat_print_pp --
+ *	ENV->memp_stat_print pre/post processing.
+ *
+ * PUBLIC: int __memp_stat_print_pp __P((DB_ENV *, u_int32_t));
+ */
+int
+__memp_stat_print_pp(dbenv, flags)
+	DB_ENV *dbenv;
+	u_int32_t flags;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "DB_ENV->memp_stat_print", DB_INIT_MPOOL);
+
+#define	DB_STAT_MEMP_FLAGS						\
+	(DB_STAT_ALL | DB_STAT_CLEAR | DB_STAT_MEMP_HASH)
+	if ((ret = __db_fchk(env,
+	    "DB_ENV->memp_stat_print", flags, DB_STAT_MEMP_FLAGS)) != 0)
+		return (ret);
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_stat_print(env, flags)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+#define	FMAP_ENTRIES	200			/* Files we map. */
+
+/*
+ * __memp_stat_print --
+ *	ENV->memp_stat_print method.
+ *
+ * PUBLIC: int  __memp_stat_print __P((ENV *, u_int32_t));
+ */
+int
+__memp_stat_print(env, flags)
+	ENV *env;
+	u_int32_t flags;
+{
+	u_int32_t orig_flags;
+	int ret;
+
+	orig_flags = flags;
+	LF_CLR(DB_STAT_CLEAR | DB_STAT_SUBSYSTEM);
+	if (flags == 0 || LF_ISSET(DB_STAT_ALL)) {
+		ret = __memp_print_stats(env,
+		    LF_ISSET(DB_STAT_ALL) ? flags : orig_flags);
+		if (flags == 0 || ret != 0)
+			return (ret);
+	}
+
+	if (LF_ISSET(DB_STAT_ALL | DB_STAT_MEMP_HASH) &&
+	    (ret = __memp_print_all(env, orig_flags)) != 0)
+		return (ret);
+
+	return (0);
+}
+
+/*
+ * __memp_print_stats --
+ *	Display default mpool region statistics.
+ */
+static int
+__memp_print_stats(env, flags)
+	ENV *env;
+	u_int32_t flags;
+{
+	DB_MPOOL_FSTAT **fsp, **tfsp;
+	DB_MPOOL_STAT *gsp;
+	int ret;
+
+	if ((ret = __memp_stat(env, &gsp, &fsp, flags)) != 0)
+		return (ret);
+
+	if (LF_ISSET(DB_STAT_ALL))
+		__db_msg(env, "Default cache region information:");
+	__db_dlbytes(env, "Total cache size",
+	    (u_long)gsp->st_gbytes, (u_long)0, (u_long)gsp->st_bytes);
+	__db_dl(env, "Number of caches", (u_long)gsp->st_ncache);
+	__db_dl(env, "Maximum number of caches", (u_long)gsp->st_max_ncache);
+	__db_dlbytes(env, "Pool individual cache size",
+	    (u_long)0, (u_long)0, (u_long)gsp->st_regsize);
+	__db_dlbytes(env, "Maximum memory-mapped file size",
+	    (u_long)0, (u_long)0, (u_long)gsp->st_mmapsize);
+	STAT_LONG("Maximum open file descriptors", gsp->st_maxopenfd);
+	STAT_LONG("Maximum sequential buffer writes", gsp->st_maxwrite);
+	STAT_LONG("Sleep after writing maximum sequential buffers",
+	    gsp->st_maxwrite_sleep);
+	__db_dl(env,
+	    "Requested pages mapped into the process' address space",
+	    (u_long)gsp->st_map);
+	__db_dl_pct(env, "Requested pages found in the cache",
+	    (u_long)gsp->st_cache_hit, DB_PCT(
+	    gsp->st_cache_hit, gsp->st_cache_hit + gsp->st_cache_miss), NULL);
+	__db_dl(env, "Requested pages not found in the cache",
+	    (u_long)gsp->st_cache_miss);
+	__db_dl(env,
+	    "Pages created in the cache", (u_long)gsp->st_page_create);
+	__db_dl(env, "Pages read into the cache", (u_long)gsp->st_page_in);
+	__db_dl(env, "Pages written from the cache to the backing file",
+	    (u_long)gsp->st_page_out);
+	__db_dl(env, "Clean pages forced from the cache",
+	    (u_long)gsp->st_ro_evict);
+	__db_dl(env, "Dirty pages forced from the cache",
+	    (u_long)gsp->st_rw_evict);
+	__db_dl(env, "Dirty pages written by trickle-sync thread",
+	    (u_long)gsp->st_page_trickle);
+	__db_dl(env, "Current total page count",
+	    (u_long)gsp->st_pages);
+	__db_dl(env, "Current clean page count",
+	    (u_long)gsp->st_page_clean);
+	__db_dl(env, "Current dirty page count",
+	    (u_long)gsp->st_page_dirty);
+	__db_dl(env, "Number of hash buckets used for page location",
+	    (u_long)gsp->st_hash_buckets);
+	__db_dl(env, "Assumed page size used",
+	    (u_long)gsp->st_pagesize);
+	__db_dl(env,
+	    "Total number of times hash chains searched for a page",
+	    (u_long)gsp->st_hash_searches);
+	__db_dl(env, "The longest hash chain searched for a page",
+	    (u_long)gsp->st_hash_longest);
+	__db_dl(env,
+	    "Total number of hash chain entries checked for page",
+	    (u_long)gsp->st_hash_examined);
+	__db_dl_pct(env,
+	    "The number of hash bucket locks that required waiting",
+	    (u_long)gsp->st_hash_wait, DB_PCT(
+	    gsp->st_hash_wait, gsp->st_hash_wait + gsp->st_hash_nowait), NULL);
+	__db_dl_pct(env,
+    "The maximum number of times any hash bucket lock was waited for",
+	    (u_long)gsp->st_hash_max_wait, DB_PCT(gsp->st_hash_max_wait,
+	    gsp->st_hash_max_wait + gsp->st_hash_max_nowait), NULL);
+	__db_dl_pct(env,
+	    "The number of region locks that required waiting",
+	    (u_long)gsp->st_region_wait, DB_PCT(gsp->st_region_wait,
+	    gsp->st_region_wait + gsp->st_region_nowait), NULL);
+	__db_dl(env, "The number of buffers frozen",
+	    (u_long)gsp->st_mvcc_frozen);
+	__db_dl(env, "The number of buffers thawed",
+	    (u_long)gsp->st_mvcc_thawed);
+	__db_dl(env, "The number of frozen buffers freed",
+	    (u_long)gsp->st_mvcc_freed);
+	__db_dl(env, "The number of page allocations", (u_long)gsp->st_alloc);
+	__db_dl(env,
+	    "The number of hash buckets examined during allocations",
+	    (u_long)gsp->st_alloc_buckets);
+	__db_dl(env,
+	    "The maximum number of hash buckets examined for an allocation",
+	    (u_long)gsp->st_alloc_max_buckets);
+	__db_dl(env, "The number of pages examined during allocations",
+	    (u_long)gsp->st_alloc_pages);
+	__db_dl(env, "The max number of pages examined for an allocation",
+	    (u_long)gsp->st_alloc_max_pages);
+	__db_dl(env, "Threads waited on page I/O", (u_long)gsp->st_io_wait);
+	__db_dl(env, "The number of times a sync is interrupted",
+	    (u_long)gsp->st_sync_interrupted);
+
+	for (tfsp = fsp; fsp != NULL && *tfsp != NULL; ++tfsp) {
+		if (LF_ISSET(DB_STAT_ALL))
+			__db_msg(env, "%s", DB_GLOBAL(db_line));
+		__db_msg(env, "Pool File: %s", (*tfsp)->file_name);
+		__db_dl(env, "Page size", (u_long)(*tfsp)->st_pagesize);
+		__db_dl(env,
+		    "Requested pages mapped into the process' address space",
+		    (u_long)(*tfsp)->st_map);
+		__db_dl_pct(env, "Requested pages found in the cache",
+		    (u_long)(*tfsp)->st_cache_hit, DB_PCT((*tfsp)->st_cache_hit,
+		    (*tfsp)->st_cache_hit + (*tfsp)->st_cache_miss), NULL);
+		__db_dl(env, "Requested pages not found in the cache",
+		    (u_long)(*tfsp)->st_cache_miss);
+		__db_dl(env, "Pages created in the cache",
+		    (u_long)(*tfsp)->st_page_create);
+		__db_dl(env, "Pages read into the cache",
+		    (u_long)(*tfsp)->st_page_in);
+		__db_dl(env,
+		    "Pages written from the cache to the backing file",
+		    (u_long)(*tfsp)->st_page_out);
+	}
+
+	__os_ufree(env, fsp);
+	__os_ufree(env, gsp);
+	return (0);
+}
+
+/*
+ * __memp_print_all --
+ *	Display debugging mpool region statistics.
+ */
+static int
+__memp_print_all(env, flags)
+	ENV *env;
+	u_int32_t flags;
+{
+	static const FN cfn[] = {
+		{ DB_MPOOL_NOFILE,	"DB_MPOOL_NOFILE" },
+		{ DB_MPOOL_UNLINK,	"DB_MPOOL_UNLINK" },
+		{ 0,			NULL }
+	};
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	MPOOL *mp;
+	roff_t fmap[FMAP_ENTRIES + 1];
+	u_int32_t i, cnt;
+	int ret;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	ret = 0;
+
+	MPOOL_SYSTEM_LOCK(env);
+
+	__db_print_reginfo(env, dbmp->reginfo, "Mpool", flags);
+	__db_msg(env, "%s", DB_GLOBAL(db_line));
+
+	__db_msg(env, "MPOOL structure:");
+	__mutex_print_debug_single(
+	    env, "MPOOL region mutex", mp->mtx_region, flags);
+	STAT_LSN("Maximum checkpoint LSN", &mp->lsn);
+	STAT_ULONG("Hash table entries", mp->htab_buckets);
+	STAT_ULONG("Hash table last-checked", mp->last_checked);
+	STAT_ULONG("Hash table LRU count", mp->lru_count);
+	STAT_ULONG("Put counter", mp->put_counter);
+
+	__db_msg(env, "%s", DB_GLOBAL(db_line));
+	__db_msg(env, "DB_MPOOL handle information:");
+	__mutex_print_debug_single(
+	    env, "DB_MPOOL handle mutex", dbmp->mutex, flags);
+	STAT_ULONG("Underlying cache regions", mp->nreg);
+
+	__db_msg(env, "%s", DB_GLOBAL(db_line));
+	__db_msg(env, "DB_MPOOLFILE structures:");
+	for (cnt = 0, dbmfp = TAILQ_FIRST(&dbmp->dbmfq);
+	    dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q), ++cnt) {
+		__db_msg(env, "File #%lu: %s: per-process, %s",
+		    (u_long)cnt + 1, __memp_fn(dbmfp),
+		    F_ISSET(dbmfp, MP_READONLY) ? "readonly" : "read/write");
+		STAT_ULONG("Reference count", dbmfp->ref);
+		STAT_ULONG("Pinned block reference count", dbmfp->ref);
+		STAT_ULONG("Clear length", dbmfp->clear_len);
+		__db_print_fileid(env, dbmfp->fileid, "\tID");
+		STAT_ULONG("File type", dbmfp->ftype);
+		STAT_ULONG("LSN offset", dbmfp->lsn_offset);
+		STAT_ULONG("Max gbytes", dbmfp->gbytes);
+		STAT_ULONG("Max bytes", dbmfp->bytes);
+		STAT_ULONG("Cache priority", dbmfp->priority);
+		STAT_POINTER("mmap address", dbmfp->addr);
+		STAT_ULONG("mmap length", dbmfp->len);
+		__db_prflags(env, NULL, dbmfp->flags, cfn, NULL, "\tFlags");
+		__db_print_fh(env, "File handle", dbmfp->fhp, flags);
+	}
+
+	__db_msg(env, "%s", DB_GLOBAL(db_line));
+	__db_msg(env, "MPOOLFILE structures:");
+	cnt = 0;
+	ret = __memp_walk_files(env, mp, __memp_print_files, fmap, &cnt, flags);
+	MPOOL_SYSTEM_UNLOCK(env);
+	if (ret != 0)
+		return (ret);
+
+	if (cnt < FMAP_ENTRIES)
+		fmap[cnt] = INVALID_ROFF;
+	else
+		fmap[FMAP_ENTRIES] = INVALID_ROFF;
+
+	/* Dump the individual caches. */
+	for (i = 0; i < mp->nreg; ++i) {
+		__db_msg(env, "%s", DB_GLOBAL(db_line));
+		__db_msg(env, "Cache #%d:", i + 1);
+		if (i > 0)
+			__env_alloc_print(&dbmp->reginfo[i], flags);
+		if ((ret = __memp_print_hash(
+		    env, dbmp, &dbmp->reginfo[i], fmap, flags)) != 0)
+			break;
+	}
+
+	return (ret);
+}
+
+static int
+__memp_print_files(env, mfp, argp, countp, flags)
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *argp;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	roff_t *fmap;
+	DB_MPOOL *dbmp;
+	u_int32_t mfp_flags;
+	static const FN fn[] = {
+		{ MP_CAN_MMAP,		"MP_CAN_MMAP" },
+		{ MP_DIRECT,		"MP_DIRECT" },
+		{ MP_EXTENT,		"MP_EXTENT" },
+		{ MP_FAKE_DEADFILE,	"deadfile" },
+		{ MP_FAKE_FILEWRITTEN,	"file written" },
+		{ MP_FAKE_NB,		"no backing file" },
+		{ MP_FAKE_UOC,		"unlink on close" },
+		{ MP_NOT_DURABLE,	"not durable" },
+		{ MP_TEMP,		"MP_TEMP" },
+		{ 0,			NULL }
+	};
+
+	dbmp = env->mp_handle;
+	fmap = argp;
+
+	__db_msg(env, "File #%d: %s", *countp + 1, __memp_fns(dbmp, mfp));
+	__mutex_print_debug_single(env, "Mutex", mfp->mutex, flags);
+
+	MUTEX_LOCK(env, mfp->mutex);
+	STAT_ULONG("Reference count", mfp->mpf_cnt);
+	STAT_ULONG("Block count", mfp->block_cnt);
+	STAT_ULONG("Last page number", mfp->last_pgno);
+	STAT_ULONG("Original last page number", mfp->orig_last_pgno);
+	STAT_ULONG("Maximum page number", mfp->maxpgno);
+	STAT_LONG("Type", mfp->ftype);
+	STAT_LONG("Priority", mfp->priority);
+	STAT_LONG("Page's LSN offset", mfp->lsn_off);
+	STAT_LONG("Page's clear length", mfp->clear_len);
+
+	__db_print_fileid(env,
+	    R_ADDR(dbmp->reginfo, mfp->fileid_off), "\tID");
+
+	mfp_flags = 0;
+	if (mfp->deadfile)
+		FLD_SET(mfp_flags, MP_FAKE_DEADFILE);
+	if (mfp->file_written)
+		FLD_SET(mfp_flags, MP_FAKE_FILEWRITTEN);
+	if (mfp->no_backing_file)
+		FLD_SET(mfp_flags, MP_FAKE_NB);
+	if (mfp->unlink_on_close)
+		FLD_SET(mfp_flags, MP_FAKE_UOC);
+	__db_prflags(env, NULL, mfp_flags, fn, NULL, "\tFlags");
+
+	if (*countp < FMAP_ENTRIES)
+		fmap[*countp] = R_OFFSET(dbmp->reginfo, mfp);
+	(*countp)++;
+	MUTEX_UNLOCK(env, mfp->mutex);
+	return (0);
+}
+
+/*
+ * __memp_print_hash --
+ *	Display hash bucket statistics for a cache.
+ */
+static int
+__memp_print_hash(env, dbmp, reginfo, fmap, flags)
+	ENV *env;
+	DB_MPOOL *dbmp;
+	REGINFO *reginfo;
+	roff_t *fmap;
+	u_int32_t flags;
+{
+	BH *bhp, *vbhp;
+	DB_MPOOL_HASH *hp;
+	DB_MSGBUF mb;
+	MPOOL *c_mp;
+	u_int32_t bucket;
+
+	c_mp = reginfo->primary;
+	DB_MSGBUF_INIT(&mb);
+
+	/* Display the hash table list of BH's. */
+	__db_msg(env,
+	    "BH hash table (%lu hash slots)", (u_long)c_mp->htab_buckets);
+	__db_msg(env, "bucket #: priority, I/O wait, [mutex]");
+	__db_msg(env, "\tpageno, file, ref, LSN, address, priority, flags");
+
+	for (hp = R_ADDR(reginfo, c_mp->htab),
+	    bucket = 0; bucket < c_mp->htab_buckets; ++hp, ++bucket) {
+		MUTEX_READLOCK(env, hp->mtx_hash);
+		if ((bhp = SH_TAILQ_FIRST(&hp->hash_bucket, __bh)) != NULL) {
+			__db_msgadd(env, &mb,
+			    "bucket %lu: %lu (%lu dirty)",
+			    (u_long)bucket, (u_long)hp->hash_io_wait,
+			    (u_long)atomic_read(&hp->hash_page_dirty));
+			if (hp->hash_frozen != 0)
+				__db_msgadd(env, &mb, "(MVCC %lu/%lu/%lu) ",
+				    (u_long)hp->hash_frozen,
+				    (u_long)hp->hash_thawed,
+				    (u_long)hp->hash_frozen_freed);
+			__mutex_print_debug_stats(
+			    env, &mb, hp->mtx_hash, flags);
+			DB_MSGBUF_FLUSH(env, &mb);
+		}
+		for (; bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, hq, __bh)) {
+			__memp_print_bh(env, dbmp, NULL, bhp, fmap);
+
+			/* Print the version chain, if it exists. */
+			for (vbhp = SH_CHAIN_PREV(bhp, vc, __bh);
+			    vbhp != NULL;
+			    vbhp = SH_CHAIN_PREV(vbhp, vc, __bh)) {
+				__memp_print_bh(env, dbmp,
+				    " next:\t", vbhp, fmap);
+			}
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_print_bh --
+ *	Display a BH structure.
+ */
+static void
+__memp_print_bh(env, dbmp, prefix, bhp, fmap)
+	ENV *env;
+	DB_MPOOL *dbmp;
+	const char *prefix;
+	BH *bhp;
+	roff_t *fmap;
+{
+	static const FN fn[] = {
+		{ BH_CALLPGIN,		"callpgin" },
+		{ BH_DIRTY,		"dirty" },
+		{ BH_DIRTY_CREATE,	"created" },
+		{ BH_DISCARD,		"discard" },
+		{ BH_EXCLUSIVE,		"exclusive" },
+		{ BH_FREED,		"freed" },
+		{ BH_FROZEN,		"frozen" },
+		{ BH_TRASH,		"trash" },
+		{ BH_THAWED,		"thawed" },
+		{ 0,			NULL }
+	};
+	DB_MSGBUF mb;
+	int i;
+
+	DB_MSGBUF_INIT(&mb);
+
+	if (prefix != NULL)
+		__db_msgadd(env, &mb, "%s", prefix);
+	else
+		__db_msgadd(env, &mb, "\t");
+
+	for (i = 0; i < FMAP_ENTRIES; ++i)
+		if (fmap[i] == INVALID_ROFF || fmap[i] == bhp->mf_offset)
+			break;
+
+	if (fmap[i] == INVALID_ROFF)
+		__db_msgadd(env, &mb, "%5lu, %lu, ",
+		    (u_long)bhp->pgno, (u_long)bhp->mf_offset);
+	else
+		__db_msgadd(
+		    env, &mb, "%5lu, #%d, ", (u_long)bhp->pgno, i + 1);
+
+	__db_msgadd(env, &mb, "%2lu, %lu/%lu", (u_long)atomic_read(&bhp->ref),
+	    F_ISSET(bhp, BH_FROZEN) ? 0 : (u_long)LSN(bhp->buf).file,
+	    F_ISSET(bhp, BH_FROZEN) ? 0 : (u_long)LSN(bhp->buf).offset);
+	if (bhp->td_off != INVALID_ROFF)
+		__db_msgadd(env, &mb, " (@%lu/%lu)",
+		    (u_long)VISIBLE_LSN(env, bhp)->file,
+		    (u_long)VISIBLE_LSN(env, bhp)->offset);
+	__db_msgadd(env, &mb, ", %#08lx, %lu",
+	    (u_long)R_OFFSET(dbmp->reginfo, bhp), (u_long)bhp->priority);
+	__db_prflags(env, &mb, bhp->flags, fn, " (", ")");
+	DB_MSGBUF_FLUSH(env, &mb);
+}
+
+/*
+ * __memp_stat_wait --
+ *	Total hash bucket wait stats into the region.
+ */
+static void
+__memp_stat_wait(env, reginfo, mp, mstat, flags)
+	ENV *env;
+	REGINFO *reginfo;
+	MPOOL *mp;
+	DB_MPOOL_STAT *mstat;
+	u_int32_t flags;
+{
+	DB_MPOOL_HASH *hp;
+	u_int32_t i;
+	uintmax_t tmp_nowait, tmp_wait;
+
+	mstat->st_hash_max_wait = 0;
+	hp = R_ADDR(reginfo, mp->htab);
+	for (i = 0; i < mp->htab_buckets; i++, hp++) {
+		__mutex_set_wait_info(
+		    env, hp->mtx_hash, &tmp_wait, &tmp_nowait);
+		mstat->st_hash_nowait += tmp_nowait;
+		mstat->st_hash_wait += tmp_wait;
+		if (tmp_wait > mstat->st_hash_max_wait) {
+			mstat->st_hash_max_wait = tmp_wait;
+			mstat->st_hash_max_nowait = tmp_nowait;
+		}
+		if (LF_ISSET(DB_STAT_CLEAR |
+		    DB_STAT_SUBSYSTEM) == DB_STAT_CLEAR)
+			__mutex_clear(env, hp->mtx_hash);
+
+		mstat->st_io_wait += hp->hash_io_wait;
+		mstat->st_mvcc_frozen += hp->hash_frozen;
+		mstat->st_mvcc_thawed += hp->hash_thawed;
+		mstat->st_mvcc_freed += hp->hash_frozen_freed;
+		if (LF_ISSET(DB_STAT_CLEAR)) {
+			hp->hash_io_wait = 0;
+			hp->hash_frozen = 0;
+			hp->hash_thawed = 0;
+			hp->hash_frozen_freed = 0;
+		}
+	}
+}
+
+#else /* !HAVE_STATISTICS */
+
+int
+__memp_stat_pp(dbenv, gspp, fspp, flags)
+	DB_ENV *dbenv;
+	DB_MPOOL_STAT **gspp;
+	DB_MPOOL_FSTAT ***fspp;
+	u_int32_t flags;
+{
+	COMPQUIET(gspp, NULL);
+	COMPQUIET(fspp, NULL);
+	COMPQUIET(flags, 0);
+
+	return (__db_stat_not_built(dbenv->env));
+}
+
+int
+__memp_stat_print_pp(dbenv, flags)
+	DB_ENV *dbenv;
+	u_int32_t flags;
+{
+	COMPQUIET(flags, 0);
+
+	return (__db_stat_not_built(dbenv->env));
+}
+#endif
+
+/*
+ * __memp_stat_hash --
+ *	Total hash bucket stats (other than mutex wait) into the region.
+ *
+ * PUBLIC: void __memp_stat_hash __P((REGINFO *, MPOOL *, u_int32_t *));
+ */
+void
+__memp_stat_hash(reginfo, mp, dirtyp)
+	REGINFO *reginfo;
+	MPOOL *mp;
+	u_int32_t *dirtyp;
+{
+	DB_MPOOL_HASH *hp;
+	u_int32_t dirty, i;
+
+	hp = R_ADDR(reginfo, mp->htab);
+	for (i = 0, dirty = 0; i < mp->htab_buckets; i++, hp++)
+		dirty += (u_int32_t)atomic_read(&hp->hash_page_dirty);
+	*dirtyp = dirty;
+}
diff --git a/mp/mp_sync.c b/mp/mp_sync.c
new file mode 100644
index 0000000..7490445
--- /dev/null
+++ b/mp/mp_sync.c
@@ -0,0 +1,919 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+#include "dbinc/db_page.h"
+#include "dbinc/hash.h"
+
+typedef struct {
+	DB_MPOOL_HASH *track_hp;	/* Hash bucket. */
+
+	roff_t	  track_off;		/* Page file offset. */
+	db_pgno_t track_pgno;		/* Page number. */
+} BH_TRACK;
+
+static int __bhcmp __P((const void *, const void *));
+static int __memp_close_flush_files __P((ENV *, int));
+static int __memp_sync_files __P((ENV *));
+static int __memp_sync_file __P((ENV *,
+		MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+
+/*
+ * __memp_walk_files --
+ * PUBLIC: int __memp_walk_files __P((ENV *, MPOOL *,
+ * PUBLIC:	int (*) __P((ENV *, MPOOLFILE *, void *,
+ * PUBLIC:	u_int32_t *, u_int32_t)), void *, u_int32_t *, u_int32_t));
+ */
+int
+__memp_walk_files(env, mp, func, arg, countp, flags)
+	ENV *env;
+	MPOOL *mp;
+	int (*func)__P((ENV *, MPOOLFILE *, void *, u_int32_t *, u_int32_t));
+	void *arg;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOLFILE *mfp;
+	int i, ret, t_ret;
+
+	dbmp = env->mp_handle;
+	ret = 0;
+
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+	for (i = 0; i < MPOOL_FILE_BUCKETS; i++, hp++) {
+		MUTEX_LOCK(env, hp->mtx_hash);
+		SH_TAILQ_FOREACH(mfp, &hp->hash_bucket, q, __mpoolfile) {
+			if ((t_ret = func(env,
+			    mfp, arg, countp, flags)) != 0 && ret == 0)
+				ret = t_ret;
+			if (ret != 0 && !LF_ISSET(DB_STAT_MEMP_NOERROR))
+				break;
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+		if (ret != 0 && !LF_ISSET(DB_STAT_MEMP_NOERROR))
+			break;
+	}
+	return (ret);
+}
+
+/*
+ * __memp_sync_pp --
+ *	ENV->memp_sync pre/post processing.
+ *
+ * PUBLIC: int __memp_sync_pp __P((DB_ENV *, DB_LSN *));
+ */
+int
+__memp_sync_pp(dbenv, lsnp)
+	DB_ENV *dbenv;
+	DB_LSN *lsnp;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "memp_sync", DB_INIT_MPOOL);
+
+	/*
+	 * If no LSN is provided, flush the entire cache (reasonable usage
+	 * even if there's no log subsystem configured).
+	 */
+	if (lsnp != NULL)
+		ENV_REQUIRES_CONFIG(env,
+		    env->lg_handle, "memp_sync", DB_INIT_LOG);
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_sync(env, DB_SYNC_CACHE, lsnp)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_sync --
+ *	ENV->memp_sync.
+ *
+ * PUBLIC: int __memp_sync __P((ENV *, u_int32_t, DB_LSN *));
+ */
+int
+__memp_sync(env, flags, lsnp)
+	ENV *env;
+	u_int32_t flags;
+	DB_LSN *lsnp;
+{
+	DB_MPOOL *dbmp;
+	MPOOL *mp;
+	int interrupted, ret;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+
+	/* If we've flushed to the requested LSN, return that information. */
+	if (lsnp != NULL) {
+		MPOOL_SYSTEM_LOCK(env);
+		if (LOG_COMPARE(lsnp, &mp->lsn) <= 0) {
+			*lsnp = mp->lsn;
+
+			MPOOL_SYSTEM_UNLOCK(env);
+			return (0);
+		}
+		MPOOL_SYSTEM_UNLOCK(env);
+	}
+
+	if ((ret =
+	    __memp_sync_int(env, NULL, 0, flags, NULL, &interrupted)) != 0)
+		return (ret);
+
+	if (!interrupted && lsnp != NULL) {
+		MPOOL_SYSTEM_LOCK(env);
+		if (LOG_COMPARE(lsnp, &mp->lsn) > 0)
+			mp->lsn = *lsnp;
+		MPOOL_SYSTEM_UNLOCK(env);
+	}
+
+	return (0);
+}
+
+/*
+ * __memp_fsync_pp --
+ *	DB_MPOOLFILE->sync pre/post processing.
+ *
+ * PUBLIC: int __memp_fsync_pp __P((DB_MPOOLFILE *));
+ */
+int
+__memp_fsync_pp(dbmfp)
+	DB_MPOOLFILE *dbmfp;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbmfp->env;
+
+	MPF_ILLEGAL_BEFORE_OPEN(dbmfp, "DB_MPOOLFILE->sync");
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_fsync(dbmfp)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_fsync --
+ *	DB_MPOOLFILE->sync.
+ *
+ * PUBLIC: int __memp_fsync __P((DB_MPOOLFILE *));
+ */
+int
+__memp_fsync(dbmfp)
+	DB_MPOOLFILE *dbmfp;
+{
+	MPOOLFILE *mfp;
+
+	mfp = dbmfp->mfp;
+
+	/*
+	 * If this handle doesn't have a file descriptor that's open for
+	 * writing, or if the file is a temporary, or if the file hasn't
+	 * been written since it was flushed, there's no reason to proceed
+	 * further.
+	 */
+	if (F_ISSET(dbmfp, MP_READONLY))
+		return (0);
+
+	if (F_ISSET(dbmfp->mfp, MP_TEMP) || dbmfp->mfp->no_backing_file)
+		return (0);
+
+	if (mfp->file_written == 0)
+		return (0);
+
+	return (__memp_sync_int(
+	    dbmfp->env, dbmfp, 0, DB_SYNC_FILE, NULL, NULL));
+}
+
+/*
+ * __mp_xxx_fh --
+ *	Return a file descriptor for DB 1.85 compatibility locking.
+ *
+ * PUBLIC: int __mp_xxx_fh __P((DB_MPOOLFILE *, DB_FH **));
+ */
+int
+__mp_xxx_fh(dbmfp, fhp)
+	DB_MPOOLFILE *dbmfp;
+	DB_FH **fhp;
+{
+	int ret;
+
+	/*
+	 * This is a truly spectacular layering violation, intended ONLY to
+	 * support compatibility for the DB 1.85 DB->fd call.
+	 *
+	 * Sync the database file to disk, creating the file as necessary.
+	 *
+	 * We skip the MP_READONLY and MP_TEMP tests done by memp_fsync(3).
+	 * The MP_READONLY test isn't interesting because we will either
+	 * already have a file descriptor (we opened the database file for
+	 * reading) or we aren't readonly (we created the database which
+	 * requires write privileges).  The MP_TEMP test isn't interesting
+	 * because we want to write to the backing file regardless so that
+	 * we get a file descriptor to return.
+	 */
+	if ((*fhp = dbmfp->fhp) != NULL)
+		return (0);
+
+	if ((ret = __memp_sync_int(
+	    dbmfp->env, dbmfp, 0, DB_SYNC_FILE, NULL, NULL)) == 0)
+		*fhp = dbmfp->fhp;
+	return (ret);
+}
+
+/*
+ * __memp_sync_int --
+ *	Mpool sync internal function.
+ *
+ * PUBLIC: int __memp_sync_int __P((ENV *,
+ * PUBLIC:     DB_MPOOLFILE *, u_int32_t, u_int32_t, u_int32_t *, int *));
+ */
+int
+__memp_sync_int(env, dbmfp, trickle_max, flags, wrote_totalp, interruptedp)
+	ENV *env;
+	DB_MPOOLFILE *dbmfp;
+	u_int32_t trickle_max, flags, *wrote_totalp;
+	int *interruptedp;
+{
+	BH *bhp;
+	BH_TRACK *bharray;
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *c_mp, *mp;
+	MPOOLFILE *mfp;
+	db_mutex_t mutex;
+	roff_t last_mf_offset;
+	u_int32_t ar_cnt, ar_max, i, n_cache, remaining, wrote_total;
+	int dirty, filecnt, maxopenfd, required_write, ret, t_ret;
+	int wrote_cnt;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	last_mf_offset = INVALID_ROFF;
+	filecnt = wrote_total = 0;
+
+	if (wrote_totalp != NULL)
+		*wrote_totalp = 0;
+	if (interruptedp != NULL)
+		*interruptedp = 0;
+
+	/*
+	 * If we're flushing the cache, it's a checkpoint or we're flushing a
+	 * specific file, we really have to write the blocks and we have to
+	 * confirm they made it to disk.  Otherwise, we can skip a block if
+	 * it's hard to get.
+	 */
+	required_write = LF_ISSET(DB_SYNC_CACHE |
+	    DB_SYNC_CHECKPOINT | DB_SYNC_FILE | DB_SYNC_QUEUE_EXTENT);
+
+	/* Get shared configuration information. */
+	MPOOL_SYSTEM_LOCK(env);
+	maxopenfd = mp->mp_maxopenfd;
+	MPOOL_SYSTEM_UNLOCK(env);
+
+	/* Assume one dirty page per bucket. */
+	ar_max = mp->nreg * mp->htab_buckets;
+	if ((ret =
+	    __os_malloc(env, ar_max * sizeof(BH_TRACK), &bharray)) != 0)
+		return (ret);
+
+	/*
+	 * Walk each cache's list of buffers and mark all dirty buffers to be
+	 * written and all dirty buffers to be potentially written, depending
+	 * on our flags.
+	 */
+	for (ar_cnt = 0, n_cache = 0; n_cache < mp->nreg; ++n_cache) {
+		c_mp = dbmp->reginfo[n_cache].primary;
+
+		hp = R_ADDR(&dbmp->reginfo[n_cache], c_mp->htab);
+		for (i = 0; i < c_mp->htab_buckets; i++, hp++) {
+			/*
+			 * We can check for empty buckets before locking as
+			 * we only care if the pointer is zero or non-zero.
+			 * We can ignore empty or clean buckets because we
+			 * only need write buffers that were dirty before
+			 * we started.
+			 */
+#ifdef DIAGNOSTIC
+			if (SH_TAILQ_FIRST(&hp->hash_bucket, __bh) == NULL)
+#else
+			if (atomic_read(&hp->hash_page_dirty) == 0)
+#endif
+				continue;
+
+			dirty = 0;
+			MUTEX_LOCK(env, hp->mtx_hash);
+			SH_TAILQ_FOREACH(bhp, &hp->hash_bucket, hq, __bh) {
+				/* Always ignore clean pages. */
+				if (!F_ISSET(bhp, BH_DIRTY))
+					continue;
+
+				dirty++;
+				mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+
+				/*
+				 * Ignore in-memory files, unless the file is
+				 * specifically being flushed.
+				 */
+				if (mfp->no_backing_file)
+					continue;
+				if (!LF_ISSET(DB_SYNC_FILE) &&
+				    F_ISSET(mfp, MP_TEMP))
+					continue;
+
+				/*
+				 * Ignore files that aren't involved in DB's
+				 * transactional operations during checkpoints.
+				 */
+				if (LF_ISSET(DB_SYNC_CHECKPOINT) &&
+				    mfp->lsn_off == DB_LSN_OFF_NOTSET)
+					continue;
+
+				/*
+				 * Ignore files that aren't Queue extent files
+				 * if we're flushing a Queue file with extents.
+				 */
+				if (LF_ISSET(DB_SYNC_QUEUE_EXTENT) &&
+				    !F_ISSET(mfp, MP_EXTENT))
+					continue;
+
+				/*
+				 * If we're flushing a specific file, see if
+				 * this page is from that file.
+				 */
+				if (dbmfp != NULL && mfp != dbmfp->mfp)
+					continue;
+
+				/* Track the buffer, we want it. */
+				bharray[ar_cnt].track_hp = hp;
+				bharray[ar_cnt].track_pgno = bhp->pgno;
+				bharray[ar_cnt].track_off = bhp->mf_offset;
+				ar_cnt++;
+
+				/*
+				 * If we run out of space, double and continue.
+				 * Don't stop at trickle_max, we want to sort
+				 * as large a sample set as possible in order
+				 * to minimize disk seeks.
+				 */
+				if (ar_cnt >= ar_max) {
+					if ((ret = __os_realloc(env,
+					    (ar_max * 2) * sizeof(BH_TRACK),
+					    &bharray)) != 0)
+						break;
+					ar_max *= 2;
+				}
+			}
+
+			if (ret != 0)
+				goto err;
+			/*
+			 * We are only checking this in diagnostic mode
+			 * since it requires extra latching to keep the count
+			 * in sync with the number of bits counted.
+			 */
+			DB_ASSERT(env,
+			    dirty == (int)atomic_read(&hp->hash_page_dirty));
+			MUTEX_UNLOCK(env, hp->mtx_hash);
+
+			/* Check if the call has been interrupted. */
+			if (LF_ISSET(DB_SYNC_INTERRUPT_OK) && FLD_ISSET(
+			    mp->config_flags, DB_MEMP_SYNC_INTERRUPT)) {
+				STAT(++mp->stat.st_sync_interrupted);
+				if (interruptedp != NULL)
+					*interruptedp = 1;
+				goto err;
+			}
+		}
+	}
+
+	/* If there no buffers to write, we're done. */
+	if (ar_cnt == 0)
+		goto done;
+
+	/*
+	 * Write the buffers in file/page order, trying to reduce seeks by the
+	 * filesystem and, when pages are smaller than filesystem block sizes,
+	 * reduce the actual number of writes.
+	 */
+	if (ar_cnt > 1)
+		qsort(bharray, ar_cnt, sizeof(BH_TRACK), __bhcmp);
+
+	/*
+	 * If we're trickling buffers, only write enough to reach the correct
+	 * percentage.
+	 */
+	if (LF_ISSET(DB_SYNC_TRICKLE) && ar_cnt > trickle_max)
+		ar_cnt = trickle_max;
+
+	/*
+	 * Flush the log.  We have to ensure the log records reflecting the
+	 * changes on the database pages we're writing have already made it
+	 * to disk.  We still have to check the log each time we write a page
+	 * (because pages we are about to write may be modified after we have
+	 * flushed the log), but in general this will at least avoid any I/O
+	 * on the log's part.
+	 */
+	if (LOGGING_ON(env) && (ret = __log_flush(env, NULL)) != 0)
+		goto err;
+
+	/*
+	 * Walk the array, writing buffers.  When we write a buffer, we NULL
+	 * out its hash bucket pointer so we don't process a slot more than
+	 * once.
+	 */
+	for (i = wrote_cnt = 0, remaining = ar_cnt; remaining > 0; ++i) {
+		if (i >= ar_cnt) {
+			i = 0;
+			__os_yield(env, 1, 0);
+		}
+		if ((hp = bharray[i].track_hp) == NULL)
+			continue;
+
+		/* Lock the hash bucket and find the buffer. */
+		mutex = hp->mtx_hash;
+		MUTEX_READLOCK(env, mutex);
+		SH_TAILQ_FOREACH(bhp, &hp->hash_bucket, hq, __bh)
+			if (bhp->pgno == bharray[i].track_pgno &&
+			    bhp->mf_offset == bharray[i].track_off)
+				break;
+
+		/*
+		 * If we can't find the buffer we're done, somebody else had
+		 * to have written it.
+		 *
+		 * If the buffer isn't dirty, we're done, there's no work
+		 * needed.
+		 */
+		if (bhp == NULL || !F_ISSET(bhp, BH_DIRTY)) {
+			MUTEX_UNLOCK(env, mutex);
+			--remaining;
+			bharray[i].track_hp = NULL;
+			continue;
+		}
+
+		/*
+		 * If the buffer is locked by another thread, ignore it, we'll
+		 * come back to it.
+		 */
+		if (F_ISSET(bhp, BH_EXCLUSIVE)) {
+			MUTEX_UNLOCK(env, mutex);
+			if (!required_write) {
+				--remaining;
+				bharray[i].track_hp = NULL;
+			}
+			continue;
+		}
+
+		/* Pin the buffer into memory. */
+		atomic_inc(env, &bhp->ref);
+		MUTEX_UNLOCK(env, mutex);
+		MUTEX_READLOCK(env, bhp->mtx_buf);
+		DB_ASSERT(env, !F_ISSET(bhp, BH_EXCLUSIVE));
+
+		/*
+		 * When swapping the hash bucket mutex for the buffer mutex,
+		 * we may have raced with an MVCC update.  In that case, we
+		 * no longer have the most recent version, and need to retry
+		 * (the buffer header we have pinned will no longer be marked
+		 * dirty, so we can't just write it).
+		 */
+		if (SH_CHAIN_HASNEXT(bhp, vc)) {
+			atomic_dec(env, &bhp->ref);
+			MUTEX_UNLOCK(env, bhp->mtx_buf);
+			continue;
+		}
+
+		/* we will dispose of this buffer. */
+		--remaining;
+		bharray[i].track_hp = NULL;
+
+		/*
+		 * If we've switched files, check to see if we're configured
+		 * to close file descriptors.
+		 */
+		if (maxopenfd != 0 && bhp->mf_offset != last_mf_offset) {
+			if (++filecnt >= maxopenfd) {
+				filecnt = 0;
+				if ((t_ret = __memp_close_flush_files(
+				    env, 1)) != 0 && ret == 0)
+					ret = t_ret;
+			}
+			last_mf_offset = bhp->mf_offset;
+		}
+
+		/*
+		 * If the buffer is dirty, we write it.  We only try to
+		 * write the buffer once.
+		 */
+		if (F_ISSET(bhp, BH_DIRTY)) {
+			mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset);
+			if ((t_ret =
+			    __memp_bhwrite(dbmp, hp, mfp, bhp, 1)) == 0) {
+				++wrote_cnt;
+				++wrote_total;
+			} else {
+				if (ret == 0)
+					ret = t_ret;
+				__db_errx
+				    (env, "%s: unable to flush page: %lu",
+				    __memp_fns(dbmp, mfp), (u_long)bhp->pgno);
+
+			}
+		}
+
+		/* Discard our buffer reference. */
+		DB_ASSERT(env, atomic_read(&bhp->ref) > 0);
+		atomic_dec(env, &bhp->ref);
+		MUTEX_UNLOCK(env, bhp->mtx_buf);
+
+		/* Check if the call has been interrupted. */
+		if (LF_ISSET(DB_SYNC_INTERRUPT_OK) &&
+		    FLD_ISSET(mp->config_flags, DB_MEMP_SYNC_INTERRUPT)) {
+			STAT(++mp->stat.st_sync_interrupted);
+			if (interruptedp != NULL)
+				*interruptedp = 1;
+			goto err;
+		}
+
+		/*
+		 * Sleep after some number of writes to avoid disk saturation.
+		 * Don't cache the max writes value, an application shutting
+		 * down might reset the value in order to do a fast flush or
+		 * checkpoint.
+		 */
+		if (!LF_ISSET(DB_SYNC_SUPPRESS_WRITE) &&
+		    !FLD_ISSET(mp->config_flags, DB_MEMP_SUPPRESS_WRITE) &&
+		    mp->mp_maxwrite != 0 && wrote_cnt >= mp->mp_maxwrite) {
+			wrote_cnt = 0;
+			__os_yield(env, 0, (u_long)mp->mp_maxwrite_sleep);
+		}
+	}
+
+done:	/*
+	 * If a write is required, we have to force the pages to disk.  We
+	 * don't do this as we go along because we want to give the OS as
+	 * much time as possible to lazily flush, and because we have to flush
+	 * files that might not even have had dirty buffers in the cache, so
+	 * we have to walk the files list.
+	 */
+	if (ret == 0 && required_write) {
+		if (dbmfp == NULL)
+			ret = __memp_sync_files(env);
+		else
+			ret = __os_fsync(env, dbmfp->fhp);
+	}
+
+	/* If we've opened files to flush pages, close them. */
+	if ((t_ret = __memp_close_flush_files(env, 0)) != 0 && ret == 0)
+		ret = t_ret;
+
+err:	__os_free(env, bharray);
+	if (wrote_totalp != NULL)
+		*wrote_totalp = wrote_total;
+
+	return (ret);
+}
+
+static int
+__memp_sync_file(env, mfp, argp, countp, flags)
+	ENV *env;
+	MPOOLFILE *mfp;
+	void *argp;
+	u_int32_t *countp;
+	u_int32_t flags;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	int ret, t_ret;
+
+	COMPQUIET(countp, NULL);
+	COMPQUIET(flags, 0);
+
+	if (!mfp->file_written || mfp->no_backing_file ||
+	    mfp->deadfile || F_ISSET(mfp, MP_TEMP))
+		return (0);
+	/*
+	 * Pin the MPOOLFILE structure into memory, and release the
+	 * region mutex allowing us to walk the linked list.  We'll
+	 * re-acquire that mutex to move to the next entry in the list.
+	 *
+	 * This works because we only need to flush current entries,
+	 * we don't care about new entries being added, and the linked
+	 * list is never re-ordered, a single pass is sufficient.  It
+	 * requires MPOOLFILE structures removed before we get to them
+	 * be flushed to disk, but that's nothing new, they could have
+	 * been removed while checkpoint was running, too.
+	 *
+	 * Once we have the MPOOLFILE lock, re-check the MPOOLFILE is
+	 * not being discarded.  (A thread removing the MPOOLFILE
+	 * will: hold the MPOOLFILE mutex, set deadfile, drop the
+	 * MPOOLFILE mutex and then acquire the region MUTEX to walk
+	 * the linked list and remove the MPOOLFILE structure.  Make
+	 * sure the MPOOLFILE wasn't marked dead while we waited for
+	 * the mutex.
+	 */
+	MUTEX_LOCK(env, mfp->mutex);
+	if (!mfp->file_written || mfp->deadfile) {
+		MUTEX_UNLOCK(env, mfp->mutex);
+		return (0);
+	}
+	++mfp->mpf_cnt;
+	MUTEX_UNLOCK(env, mfp->mutex);
+
+	/*
+	 * Look for an already open, writeable handle (fsync doesn't
+	 * work on read-only Windows handles).
+	 */
+	dbmp = env->mp_handle;
+	MUTEX_LOCK(env, dbmp->mutex);
+	TAILQ_FOREACH(dbmfp, &dbmp->dbmfq, q) {
+		if (dbmfp->mfp != mfp || F_ISSET(dbmfp, MP_READONLY))
+			continue;
+		/*
+		 * We don't want to hold the mutex while calling sync.
+		 * Increment the DB_MPOOLFILE handle ref count to pin
+		 * it into memory.
+		 */
+		++dbmfp->ref;
+		break;
+	}
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	/* If we don't find a handle we can use, open one. */
+	if (dbmfp == NULL) {
+		if ((ret = __memp_mf_sync(dbmp, mfp, 1)) != 0) {
+			__db_err(env, ret,
+			    "%s: unable to flush", (char *)
+			    R_ADDR(dbmp->reginfo, mfp->path_off));
+		}
+	} else
+		ret = __os_fsync(env, dbmfp->fhp);
+
+	/*
+	 * Re-acquire the MPOOLFILE mutex, we need it to modify the
+	 * reference count.
+	 */
+	MUTEX_LOCK(env, mfp->mutex);
+
+	/*
+	 * If we wrote the file and there are no other references (or there
+	 * is a single reference, and it's the one we opened to write
+	 * buffers during checkpoint), clear the file_written flag.  We
+	 * do this so that applications opening thousands of files don't
+	 * loop here opening and flushing those files during checkpoint.
+	 *
+	 * The danger here is if a buffer were to be written as part of
+	 * a checkpoint, and then not be flushed to disk.  This cannot
+	 * happen because we only clear file_written when there are no
+	 * other users of the MPOOLFILE in the system, and, as we hold
+	 * the region lock, no possibility of another thread of control
+	 * racing with us to open a MPOOLFILE.
+	 */
+	if (mfp->mpf_cnt == 1 || (mfp->mpf_cnt == 2 &&
+	    dbmfp != NULL && F_ISSET(dbmfp, MP_FLUSH))) {
+		mfp->file_written = 0;
+
+		/*
+		 * We may be the last reference for a MPOOLFILE, as we
+		 * weren't holding the MPOOLFILE mutex when flushing
+		 * it's buffers to disk.  If we can discard it, set
+		 * a flag to schedule a clean-out pass.   (Not likely,
+		 * I mean, what are the chances that there aren't any
+		 * buffers in the pool?  Regardless, it might happen.)
+		 */
+		if (mfp->mpf_cnt == 1 && mfp->block_cnt == 0)
+			*(int *)argp = 1;
+	}
+
+	/*
+	 * If we found the file we must close it in case we are the last
+	 * reference to the dbmfp.  NOTE: since we have incremented
+	 * mfp->mpf_cnt this cannot be the last reference to the mfp.
+	 * This is important since we are called with the hash bucket
+	 * locked.  The mfp will get freed via the cleanup pass.
+	 */
+	if (dbmfp != NULL &&
+	    (t_ret = __memp_fclose(dbmfp, DB_MPOOL_NOLOCK)) != 0 && ret == 0)
+		ret = t_ret;
+
+	--mfp->mpf_cnt;
+
+	/* Unlock the MPOOLFILE. */
+	MUTEX_UNLOCK(env, mfp->mutex);
+	return (ret);
+}
+
+/*
+ * __memp_sync_files --
+ *	Sync all the files in the environment, open or not.
+ */
+static int
+__memp_sync_files(env)
+	ENV *env;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOL_HASH *hp;
+	MPOOL *mp;
+	MPOOLFILE *mfp, *next_mfp;
+	int i, need_discard_pass, ret;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+	need_discard_pass = ret = 0;
+
+	ret = __memp_walk_files(env,
+	    mp, __memp_sync_file, &need_discard_pass, 0, DB_STAT_MEMP_NOERROR);
+
+	/*
+	 * We may need to do a last pass through the MPOOLFILE list -- if we
+	 * were the last reference to an MPOOLFILE, we need to clean it out.
+	 */
+	if (!need_discard_pass)
+		return (ret);
+
+	hp = R_ADDR(dbmp->reginfo, mp->ftab);
+	for (i = 0; i < MPOOL_FILE_BUCKETS; i++, hp++) {
+retry:		MUTEX_LOCK(env, hp->mtx_hash);
+		for (mfp = SH_TAILQ_FIRST(&hp->hash_bucket,
+		    __mpoolfile); mfp != NULL; mfp = next_mfp) {
+			next_mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile);
+			/*
+			 * Do a fast check -- we can check for zero/non-zero
+			 * without a mutex on the MPOOLFILE.  If likely to
+			 * succeed, lock the MPOOLFILE down and look for real.
+			 */
+			if (mfp->deadfile ||
+			    mfp->block_cnt != 0 || mfp->mpf_cnt != 0)
+				continue;
+
+			MUTEX_LOCK(env, mfp->mutex);
+			if (!mfp->deadfile &&
+			    mfp->block_cnt == 0 && mfp->mpf_cnt == 0) {
+				MUTEX_UNLOCK(env, hp->mtx_hash);
+				(void)__memp_mf_discard(dbmp, mfp);
+				goto retry;
+			} else
+				MUTEX_UNLOCK(env, mfp->mutex);
+		}
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+	}
+	return (ret);
+}
+
+/*
+ * __memp_mf_sync --
+ *	Flush an MPOOLFILE, when no currently open handle is available.
+ *
+ * PUBLIC: int __memp_mf_sync __P((DB_MPOOL *, MPOOLFILE *, int));
+ */
+int
+__memp_mf_sync(dbmp, mfp, locked)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+	int locked;
+{
+	DB_FH *fhp;
+	DB_MPOOL_HASH *hp;
+	ENV *env;
+	MPOOL *mp;
+	int ret, t_ret;
+	char *rpath;
+
+	COMPQUIET(hp, NULL);
+	env = dbmp->env;
+
+	/*
+	 * We need to be holding the hash lock: we're using the path name
+	 * and __memp_nameop might try and rename the file.
+	 */
+	if (!locked) {
+		mp = dbmp->reginfo[0].primary;
+		hp = R_ADDR(dbmp->reginfo, mp->ftab);
+		hp += FNBUCKET(
+		    R_ADDR(dbmp->reginfo, mfp->fileid_off), DB_FILE_ID_LEN);
+		MUTEX_LOCK(env, hp->mtx_hash);
+	}
+
+	if ((ret = __db_appname(env, DB_APP_DATA,
+	    R_ADDR(dbmp->reginfo, mfp->path_off), NULL, &rpath)) == 0) {
+		if ((ret = __os_open(env, rpath, 0, 0, 0, &fhp)) == 0) {
+			ret = __os_fsync(env, fhp);
+			if ((t_ret =
+			    __os_closehandle(env, fhp)) != 0 && ret == 0)
+				ret = t_ret;
+		}
+		__os_free(env, rpath);
+	}
+
+	if (!locked)
+		MUTEX_UNLOCK(env, hp->mtx_hash);
+
+	return (ret);
+}
+
+/*
+ * __memp_close_flush_files --
+ *	Close files opened only to flush buffers.
+ */
+static int
+__memp_close_flush_files(env, dosync)
+	ENV *env;
+	int dosync;
+{
+	DB_MPOOL *dbmp;
+	DB_MPOOLFILE *dbmfp;
+	MPOOLFILE *mfp;
+	int ret;
+
+	dbmp = env->mp_handle;
+
+	/*
+	 * The routine exists because we must close files opened by sync to
+	 * flush buffers.  There are two cases: first, extent files have to
+	 * be closed so they may be removed when empty.  Second, regular
+	 * files have to be closed so we don't run out of descriptors (for
+	 * example, an application partitioning its data into databases
+	 * based on timestamps, so there's a continually increasing set of
+	 * files).
+	 *
+	 * We mark files opened in the __memp_bhwrite() function with the
+	 * MP_FLUSH flag.  Here we walk through our file descriptor list,
+	 * and, if a file was opened by __memp_bhwrite(), we close it.
+	 */
+retry:	MUTEX_LOCK(env, dbmp->mutex);
+	TAILQ_FOREACH(dbmfp, &dbmp->dbmfq, q)
+		if (F_ISSET(dbmfp, MP_FLUSH)) {
+			F_CLR(dbmfp, MP_FLUSH);
+			MUTEX_UNLOCK(env, dbmp->mutex);
+			if (dosync) {
+				/*
+				 * If we have the only open handle on the file,
+				 * clear the dirty flag so we don't re-open and
+				 * sync it again when discarding the MPOOLFILE
+				 * structure.  Clear the flag before the sync
+				 * so can't race with a thread writing the file.
+				 */
+				mfp = dbmfp->mfp;
+				if (mfp->mpf_cnt == 1) {
+					MUTEX_LOCK(env, mfp->mutex);
+					if (mfp->mpf_cnt == 1)
+						mfp->file_written = 0;
+					MUTEX_UNLOCK(env, mfp->mutex);
+				}
+				if ((ret = __os_fsync(env, dbmfp->fhp)) != 0)
+					return (ret);
+			}
+			if ((ret = __memp_fclose(dbmfp, 0)) != 0)
+				return (ret);
+			goto retry;
+		}
+	MUTEX_UNLOCK(env, dbmp->mutex);
+
+	return (0);
+}
+
+static int
+__bhcmp(p1, p2)
+	const void *p1, *p2;
+{
+	BH_TRACK *bhp1, *bhp2;
+
+	bhp1 = (BH_TRACK *)p1;
+	bhp2 = (BH_TRACK *)p2;
+
+	/* Sort by file (shared memory pool offset). */
+	if (bhp1->track_off < bhp2->track_off)
+		return (-1);
+	if (bhp1->track_off > bhp2->track_off)
+		return (1);
+
+	/*
+	 * !!!
+	 * Defend against badly written quicksort code calling the comparison
+	 * function with two identical pointers (e.g., WATCOM C++ (Power++)).
+	 */
+	if (bhp1->track_pgno < bhp2->track_pgno)
+		return (-1);
+	if (bhp1->track_pgno > bhp2->track_pgno)
+		return (1);
+	return (0);
+}
diff --git a/mp/mp_trickle.c b/mp/mp_trickle.c
new file mode 100644
index 0000000..e92e788
--- /dev/null
+++ b/mp/mp_trickle.c
@@ -0,0 +1,112 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996-2009 Oracle.  All rights reserved.
+ *
+ * $Id$
+ */
+
+#include "db_config.h"
+
+#include "db_int.h"
+#include "dbinc/log.h"
+#include "dbinc/mp.h"
+
+static int __memp_trickle __P((ENV *, int, int *));
+
+/*
+ * __memp_trickle_pp --
+ *	ENV->memp_trickle pre/post processing.
+ *
+ * PUBLIC: int __memp_trickle_pp __P((DB_ENV *, int, int *));
+ */
+int
+__memp_trickle_pp(dbenv, pct, nwrotep)
+	DB_ENV *dbenv;
+	int pct, *nwrotep;
+{
+	DB_THREAD_INFO *ip;
+	ENV *env;
+	int ret;
+
+	env = dbenv->env;
+
+	ENV_REQUIRES_CONFIG(env,
+	    env->mp_handle, "memp_trickle", DB_INIT_MPOOL);
+
+	ENV_ENTER(env, ip);
+	REPLICATION_WRAP(env, (__memp_trickle(env, pct, nwrotep)), 0, ret);
+	ENV_LEAVE(env, ip);
+	return (ret);
+}
+
+/*
+ * __memp_trickle --
+ *	ENV->memp_trickle.
+ */
+static int
+__memp_trickle(env, pct, nwrotep)
+	ENV *env;
+	int pct, *nwrotep;
+{
+	DB_MPOOL *dbmp;
+	MPOOL *c_mp, *mp;
+	u_int32_t clean, dirty, i, need_clean, total, dtmp, wrote;
+	int ret;
+
+	dbmp = env->mp_handle;
+	mp = dbmp->reginfo[0].primary;
+
+	if (nwrotep != NULL)
+		*nwrotep = 0;
+
+	if (pct < 1 || pct > 100) {
+		__db_errx(env,
+	    "DB_ENV->memp_trickle: %d: percent must be between 1 and 100",
+		    pct);
+		return (EINVAL);
+	}
+
+	/*
+	 * Loop through the caches counting total/dirty buffers.
+	 *
+	 * XXX
+	 * Using hash_page_dirty is our only choice at the moment, but it's not
+	 * as correct as we might like in the presence of pools having more
+	 * than one page size, as a free 512B buffer may not be equivalent to
+	 * having a free 8KB buffer.
+	 */
+	for (ret = 0, i = dirty = total = 0; i < mp->nreg; ++i) {
+		c_mp = dbmp->reginfo[i].primary;
+		total += c_mp->stat.st_pages;
+		__memp_stat_hash(&dbmp->reginfo[i], c_mp, &dtmp);
+		dirty += dtmp;
+	}
+
+	/*
+	 * If there are sufficient clean buffers, no buffers or no dirty
+	 * buffers, we're done.
+	 */
+	if (total == 0 || dirty == 0)
+		return (0);
+
+	/*
+	 * The total number of pages is an exact number, but the dirty page
+	 * count can change while we're walking the hash buckets, and it's
+	 * even possible the dirty page count ends up larger than the total
+	 * number of pages.
+	 */
+	clean = total > dirty ? total - dirty : 0;
+	need_clean = (total * (u_int)pct) / 100;
+	if (clean >= need_clean)
+		return (0);
+
+	need_clean -= clean;
+	ret = __memp_sync_int(env, NULL,
+	    need_clean, DB_SYNC_TRICKLE | DB_SYNC_INTERRUPT_OK, &wrote, NULL);
+	STAT((mp->stat.st_page_trickle += wrote));
+	if (nwrotep != NULL)
+		*nwrotep = (int)wrote;
+
+	return (ret);
+}