1 files changed, 437 insertions, 0 deletions

diff --git a/db2/mp/mp_bh.c b/db2/mp/mp_bh.c
new file mode 100644
index 0000000..e1b68ce
--- /dev/null
+++ b/db2/mp/mp_bh.c
@@ -0,0 +1,437 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997
+ *	Sleepycat Software.  All rights reserved.
+ */
+#include "config.h"
+
+#ifndef lint
+static const char sccsid[] = "@(#)mp_bh.c	10.12 (Sleepycat) 8/20/97";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#endif
+
+#include "db_int.h"
+#include "shqueue.h"
+#include "db_shash.h"
+#include "mp.h"
+#include "common_ext.h"
+
+/*
+ * __memp_bhwrite --
+ *	Write the page associated with a given bucket header.
+ *
+ * PUBLIC: int __memp_bhwrite
+ * PUBLIC:     __P((DB_MPOOL *, MPOOLFILE *, BH *, int *, int *));
+ */
+int
+__memp_bhwrite(dbmp, mfp, bhp, restartp, wrotep)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+	BH *bhp;
+	int *restartp, *wrotep;
+{
+	DBT dbt;
+	DB_MPOOLFILE *dbmfp;
+	DB_MPREG *mpreg;
+
+	if (restartp != NULL)
+		*restartp = 0;
+	if (wrotep != NULL)
+		*wrotep = 0;
+
+	/*
+	 * Walk the process' DB_MPOOLFILE list and try and find a file
+	 * descriptor for this file.
+	 */
+	LOCKHANDLE(dbmp, &dbmp->mutex);
+	for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq);
+	    dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q))
+		if (dbmfp->mfp == mfp)
+			break;
+	UNLOCKHANDLE(dbmp, &dbmp->mutex);
+	if (dbmfp != NULL)
+		goto found;
+
+	/*
+	 * It's not a page from a file we've opened.  If the file requires
+	 * 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) {
+		LOCKHANDLE(dbmp, &dbmp->mutex);
+		for (mpreg = LIST_FIRST(&dbmp->dbregq);
+		    mpreg != NULL; mpreg = LIST_NEXT(mpreg, q))
+			if (mpreg->ftype == mfp->ftype)
+				break;
+		UNLOCKHANDLE(dbmp, &dbmp->mutex);
+		if (mpreg == NULL)
+			return (0);
+	}
+
+	/*
+	 * Try and open the file; ignore any error, assume it's a permissions
+	 * problem.
+	 */
+	dbt.size = mfp->pgcookie_len;
+	dbt.data = ADDR(dbmp, mfp->pgcookie_off);
+	if (__memp_fopen(dbmp, ADDR(dbmp, mfp->path_off),
+	    mfp->ftype, 0, 0, mfp->stat.st_pagesize,
+	    mfp->lsn_off, &dbt, ADDR(dbmp, mfp->fileid_off), 0, &dbmfp) != 0)
+		return (0);
+
+found:	return (__memp_pgwrite(dbmfp, bhp, restartp, wrotep));
+}
+
+/*
+ * __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;
+{
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+	size_t pagesize;
+	ssize_t nr;
+	int ret;
+
+	dbmp = dbmfp->dbmp;
+	mfp = dbmfp->mfp;
+	pagesize = mfp->stat.st_pagesize;
+
+	F_SET(bhp, BH_LOCKED | BH_TRASH);
+	LOCKBUFFER(dbmp, bhp);
+	UNLOCKREGION(dbmp);
+
+	/*
+	 * Temporary files may not yet have been created.
+	 *
+	 * Seek to the page location.
+	 */
+	ret = 0;
+	LOCKHANDLE(dbmp, &dbmfp->mutex);
+	if (dbmfp->fd == -1 || (ret =
+	    __db_lseek(dbmfp->fd, pagesize, bhp->pgno, 0, SEEK_SET)) != 0) {
+		if (!can_create) {
+			if (dbmfp->fd == -1)
+				ret = EINVAL;
+			UNLOCKHANDLE(dbmp, &dbmfp->mutex);
+			__db_err(dbmp->dbenv,
+			    "%s: page %lu doesn't exist, create flag not set",
+			    dbmfp->path, (u_long)bhp->pgno);
+			goto err;
+		}
+		UNLOCKHANDLE(dbmp, &dbmfp->mutex);
+
+		/* Clear any uninitialized data. */
+		memset(bhp->buf, 0, pagesize);
+		goto pgin;
+	}
+
+	/*
+	 * Read the page; short reads are treated like creates, although
+	 * any valid data is preserved.
+	 */
+	ret = __db_read(dbmfp->fd, bhp->buf, pagesize, &nr);
+	UNLOCKHANDLE(dbmp, &dbmfp->mutex);
+	if (ret != 0)
+		goto err;
+
+	if (nr == (ssize_t)pagesize)
+		can_create = 0;
+	else {
+		if (!can_create) {
+			ret = EINVAL;
+			goto err;
+		}
+
+		/* Clear any uninitialized data. */
+		memset(bhp->buf + nr, 0, pagesize - nr);
+	}
+
+	/* Call any pgin function. */
+pgin:	ret = mfp->ftype == 0 ? 0 : __memp_pg(dbmfp, bhp, 1);
+
+	/* Reacquire the region lock. */
+	LOCKREGION(dbmp);
+
+	/* If the pgin function succeeded, the data is now valid. */
+	if (ret == 0)
+		F_CLR(bhp, BH_TRASH);
+
+	/* Update the statistics. */
+	if (can_create) {
+		++dbmp->mp->stat.st_page_create;
+		++mfp->stat.st_page_create;
+	} else {
+		++dbmp->mp->stat.st_page_in;
+		++mfp->stat.st_page_in;
+	}
+
+	if (0) {
+err:		LOCKREGION(dbmp);
+	}
+
+	/* Release the buffer. */
+	F_CLR(bhp, BH_LOCKED);
+	UNLOCKBUFFER(dbmp, bhp);
+
+	return (ret);
+}
+
+/*
+ * __memp_pgwrite --
+ *	Write a page to a file.
+ *
+ * PUBLIC: int __memp_pgwrite __P((DB_MPOOLFILE *, BH *, int *, int *));
+ */
+int
+__memp_pgwrite(dbmfp, bhp, restartp, wrotep)
+	DB_MPOOLFILE *dbmfp;
+	BH *bhp;
+	int *restartp, *wrotep;
+{
+	DB_ENV *dbenv;
+	DB_LOG *lg_info;
+	DB_LSN lsn;
+	DB_MPOOL *dbmp;
+	MPOOL *mp;
+	MPOOLFILE *mfp;
+	size_t pagesize;
+	ssize_t nw;
+	int callpgin, ret;
+	const char *fail;
+
+	dbmp = dbmfp->dbmp;
+	dbenv = dbmp->dbenv;
+	mfp = dbmfp->mfp;
+
+	if (restartp != NULL)
+		*restartp = 0;
+	if (wrotep != NULL)
+		*wrotep = 0;
+	callpgin = 0;
+	pagesize = mfp->stat.st_pagesize;
+
+	F_SET(bhp, BH_LOCKED);
+	LOCKBUFFER(dbmp, bhp);
+	UNLOCKREGION(dbmp);
+
+	if (restartp != NULL)
+		*restartp = 1;
+
+	/* Copy the LSN off the page if we're going to need it. */
+	lg_info = dbenv->lg_info;
+	if (lg_info != NULL || F_ISSET(bhp, BH_WRITE))
+		memcpy(&lsn, bhp->buf + mfp->lsn_off, sizeof(DB_LSN));
+
+	/* Ensure the appropriate log records are on disk. */
+	if (lg_info != NULL && (ret = log_flush(lg_info, &lsn)) != 0)
+		goto err;
+
+	/*
+	 * Call any pgout function.  We set the callpgin flag so that on
+	 * error we flag that the contents of the buffer may be trash.
+	 */
+	if (mfp->ftype == 0)
+		ret = 0;
+	else {
+		callpgin = 1;
+		if ((ret = __memp_pg(dbmfp, bhp, 0)) != 0)
+			goto err;
+	}
+
+	/* Temporary files may not yet have been created. */
+	LOCKHANDLE(dbmp, &dbmfp->mutex);
+	if (dbmfp->fd == -1 && ((ret = __db_appname(dbenv, DB_APP_TMP,
+	    NULL, NULL, &dbmfp->fd, NULL)) != 0 || dbmfp->fd == -1)) {
+		UNLOCKHANDLE(dbmp, &dbmfp->mutex);
+		__db_err(dbenv, "unable to create temporary backing file");
+		goto err;
+	}
+
+	/* Write the page out. */
+	if ((ret =
+	    __db_lseek(dbmfp->fd, pagesize, bhp->pgno, 0, SEEK_SET)) != 0)
+		fail = "seek";
+	else if ((ret = __db_write(dbmfp->fd, bhp->buf, pagesize, &nw)) != 0)
+		fail = "write";
+	UNLOCKHANDLE(dbmp, &dbmfp->mutex);
+	if (ret != 0) {
+		/*
+		 * XXX
+		 * Shut the compiler up; it doesn't understand the correlation
+		 * between the failing clauses to __db_lseek and __db_write and
+		 * this ret != 0.
+		 */
+		fail = NULL;
+		goto syserr;
+	}
+
+	if (nw != (ssize_t)pagesize) {
+		ret = EIO;
+		fail = "write";
+		goto syserr;
+	}
+
+	if (wrotep != NULL)
+		*wrotep = 1;
+
+	/* Reacquire the region lock. */
+	LOCKREGION(dbmp);
+
+	/* Clean up the flags based on a successful write. */
+	F_SET(bhp, BH_CALLPGIN);
+	F_CLR(bhp, BH_DIRTY | BH_LOCKED);
+	UNLOCKBUFFER(dbmp, bhp);
+
+	/*
+	 * If we wrote a buffer which a checkpoint is waiting for, update
+	 * the count of pending buffers (both in the mpool as a whole and
+	 * for this file).  If the count for this file goes to zero, flush
+	 * the writes.
+	 *
+	 * XXX:
+	 * We ignore errors from the sync -- it makes no sense to return an
+	 * error to the calling process, so set a flag causing the sync to
+	 * be retried later.
+	 *
+	 * If the buffer we wrote has a LSN larger than the current largest
+	 * we've written for this checkpoint, update the saved value.
+	 */
+	mp = dbmp->mp;
+	if (F_ISSET(bhp, BH_WRITE)) {
+		if (log_compare(&lsn, &mp->lsn) > 0)
+			mp->lsn = lsn;
+		F_CLR(bhp, BH_WRITE);
+
+		--mp->lsn_cnt;
+		if (--mfp->lsn_cnt == 0) {
+			/*
+			 * Don't lock -- there are no atomicity issues for
+			 * fsync(2).
+			 */
+			if (__db_fsync(dbmfp->fd) != 0)
+				F_SET(mp, MP_LSN_RETRY);
+		}
+	}
+
+	/* Update I/O statistics. */
+	++mp->stat.st_page_out;
+	++mfp->stat.st_page_out;
+
+	return (0);
+
+syserr:	__db_err(dbenv,
+	    "%s: %s failed for page %lu", dbmfp->path, fail, (u_long)bhp->pgno);
+
+err:	UNLOCKBUFFER(dbmp, bhp);
+	LOCKREGION(dbmp);
+	if (callpgin)
+		F_SET(bhp, BH_CALLPGIN);
+	F_CLR(bhp, BH_LOCKED);
+	return (ret);
+}
+
+/*
+ * __memp_pg --
+ *	Call the pgin/pgout routine.
+ *
+ * PUBLIC: int __memp_pg __P((DB_MPOOLFILE *, BH *, int));
+ */
+int
+__memp_pg(dbmfp, bhp, is_pgin)
+	DB_MPOOLFILE *dbmfp;
+	BH *bhp;
+	int is_pgin;
+{
+	DBT dbt, *dbtp;
+	DB_MPOOL *dbmp;
+	DB_MPREG *mpreg;
+	MPOOLFILE *mfp;
+	int ftype, ret;
+
+	dbmp = dbmfp->dbmp;
+	mfp = dbmfp->mfp;
+
+	LOCKHANDLE(dbmp, &dbmp->mutex);
+
+	ftype = mfp->ftype;
+	for (mpreg = LIST_FIRST(&dbmp->dbregq);
+	    mpreg != NULL; mpreg = LIST_NEXT(mpreg, q)) {
+		if (ftype != mpreg->ftype)
+			continue;
+		if (mfp->pgcookie_len == 0)
+			dbtp = NULL;
+		else {
+			dbt.size = mfp->pgcookie_len;
+			dbt.data = ADDR(dbmp, mfp->pgcookie_off);
+			dbtp = &dbt;
+		}
+		UNLOCKHANDLE(dbmp, &dbmp->mutex);
+
+		if (is_pgin) {
+			if (mpreg->pgin != NULL && (ret =
+			    mpreg->pgin(bhp->pgno, bhp->buf, dbtp)) != 0)
+				goto err;
+		} else
+			if (mpreg->pgout != NULL && (ret =
+			    mpreg->pgout(bhp->pgno, bhp->buf, dbtp)) != 0)
+				goto err;
+		break;
+	}
+
+	if (mpreg == NULL)
+		UNLOCKHANDLE(dbmp, &dbmp->mutex);
+
+	return (0);
+
+err:	UNLOCKHANDLE(dbmp, &dbmp->mutex);
+	__db_err(dbmp->dbenv, "%s: %s failed for page %lu",
+	    dbmfp->path, is_pgin ? "pgin" : "pgout", (u_long)bhp->pgno);
+	return (ret);
+}
+
+/*
+ * __memp_bhfree --
+ *	Free a bucket header and its referenced data.
+ *
+ * PUBLIC: void __memp_bhfree __P((DB_MPOOL *, MPOOLFILE *, BH *, int));
+ */
+void
+__memp_bhfree(dbmp, mfp, bhp, free_mem)
+	DB_MPOOL *dbmp;
+	MPOOLFILE *mfp;
+	BH *bhp;
+	int free_mem;
+{
+	size_t off;
+
+	/* Delete the buffer header from the MPOOL hash list. */
+	off = BUCKET(dbmp->mp, OFFSET(dbmp, mfp), bhp->pgno);
+	SH_TAILQ_REMOVE(&dbmp->htab[off], bhp, mq, __bh);
+
+	/* Delete the buffer header from the LRU chain. */
+	SH_TAILQ_REMOVE(&dbmp->mp->bhq, bhp, q, __bh);
+
+	/*
+	 * If we're not reusing it immediately, free the buffer header
+	 * and data for real.
+	 */
+	if (free_mem)
+		__db_shalloc_free(dbmp->addr, bhp);
+}