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-rw-r--r--db2/mp/mp_bh.c437
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 0000000000..e1b68ce450
--- /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);
+}