diff options
Diffstat (limited to 'db2/mp/mp_bh.c')
| -rw-r--r-- | db2/mp/mp_bh.c | 592 |
1 files changed, 0 insertions, 592 deletions
diff --git a/db2/mp/mp_bh.c b/db2/mp/mp_bh.c deleted file mode 100644 index 12c53417d9..0000000000 --- a/db2/mp/mp_bh.c +++ /dev/null @@ -1,592 +0,0 @@ -/*- - * See the file LICENSE for redistribution information. - * - * Copyright (c) 1996, 1997, 1998 - * Sleepycat Software. All rights reserved. - */ -#include "config.h" - -#ifndef lint -static const char sccsid[] = "@(#)mp_bh.c 10.45 (Sleepycat) 11/25/98"; -#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" - -static int __memp_upgrade __P((DB_MPOOL *, DB_MPOOLFILE *, MPOOLFILE *)); - -/* - * __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; -{ - DB_MPOOLFILE *dbmfp; - DB_MPREG *mpreg; - int incremented, ret; - - if (restartp != NULL) - *restartp = 0; - if (wrotep != NULL) - *wrotep = 0; - incremented = 0; - - /* - * Walk the process' DB_MPOOLFILE list and find a file descriptor for - * the file. We also check that the descriptor is open for writing. - * If we find a descriptor on the file that's not open for writing, we - * try and upgrade it to make it writeable. If that fails, we're done. - */ - LOCKHANDLE(dbmp, dbmp->mutexp); - for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq); - dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q)) - if (dbmfp->mfp == mfp) { - if (F_ISSET(dbmfp, MP_READONLY) && - __memp_upgrade(dbmp, dbmfp, mfp)) { - UNLOCKHANDLE(dbmp, dbmp->mutexp); - return (0); - } - - /* - * Increment the reference count -- see the comment in - * memp_fclose(). - */ - ++dbmfp->ref; - incremented = 1; - break; - } - UNLOCKHANDLE(dbmp, dbmp->mutexp); - 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->mutexp); - for (mpreg = LIST_FIRST(&dbmp->dbregq); - mpreg != NULL; mpreg = LIST_NEXT(mpreg, q)) - if (mpreg->ftype == mfp->ftype) - break; - UNLOCKHANDLE(dbmp, dbmp->mutexp); - if (mpreg == NULL) - return (0); - } - - /* - * Try and open the file, attaching to the underlying shared area. - * - * XXX - * 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. - * - * XXX - * There's no negative cache, so we may repeatedly try and open files - * that we have previously tried (and failed) to open. - * - * Ignore any error, assume it's a permissions problem. - */ - if (F_ISSET(mfp, MP_TEMP)) - return (0); - - if (__memp_fopen(dbmp, mfp, R_ADDR(dbmp, mfp->path_off), - 0, 0, mfp->stat.st_pagesize, 0, NULL, &dbmfp) != 0) - return (0); - -found: ret = __memp_pgwrite(dbmfp, bhp, restartp, wrotep); - - if (incremented) { - LOCKHANDLE(dbmp, dbmp->mutexp); - --dbmfp->ref; - UNLOCKHANDLE(dbmp, dbmp->mutexp); - } - - 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; -{ - DB_IO db_io; - DB_MPOOL *dbmp; - MPOOLFILE *mfp; - size_t len, pagesize; - ssize_t nr; - int created, 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. We don't create - * them now, we create them when the pages have to be flushed. - */ - nr = 0; - if (dbmfp->fd == -1) - ret = 0; - else { - /* - * Ignore read errors if we have permission to create the page. - * Assume that the page doesn't exist, and that we'll create it - * when we write it out. - */ - db_io.fd_io = dbmfp->fd; - db_io.fd_lock = dbmp->reginfo.fd; - db_io.mutexp = - F_ISSET(dbmp, MP_LOCKHANDLE) ? dbmfp->mutexp : NULL; - db_io.pagesize = db_io.bytes = pagesize; - db_io.pgno = bhp->pgno; - db_io.buf = bhp->buf; - - ret = __os_io(&db_io, DB_IO_READ, &nr); - } - - created = 0; - if (nr < (ssize_t)pagesize) { - if (can_create) - created = 1; - else { - /* If we had a short read, ret may be 0. */ - if (ret == 0) - ret = EIO; - __db_err(dbmp->dbenv, - "%s: page %lu doesn't exist, create flag not set", - __memp_fn(dbmfp), (u_long)bhp->pgno); - goto err; - } - } - - /* - * Clear any bytes we didn't read that need to be cleared. If we're - * running in diagnostic mode, smash any bytes on the page that are - * unknown quantities for the caller. - */ - if (nr != (ssize_t)pagesize) { - len = mfp->clear_len == 0 ? pagesize : mfp->clear_len; - if (nr < (ssize_t)len) - memset(bhp->buf + nr, 0, len - nr); -#ifdef DIAGNOSTIC - if (nr > (ssize_t)len) - len = nr; - if (len < pagesize) - memset(bhp->buf + len, 0xdb, pagesize - len); -#endif - } - - /* Call any pgin function. */ - ret = mfp->ftype == 0 ? 0 : __memp_pg(dbmfp, bhp, 1); - - /* Unlock the buffer and reacquire the region lock. */ -err: UNLOCKBUFFER(dbmp, bhp); - LOCKREGION(dbmp); - - /* - * If no errors occurred, the data is now valid, clear the BH_TRASH - * flag; regardless, clear the lock bit and let other threads proceed. - */ - F_CLR(bhp, BH_LOCKED); - if (ret == 0) { - F_CLR(bhp, BH_TRASH); - - /* Update the statistics. */ - if (created) { - ++dbmp->mp->stat.st_page_create; - ++mfp->stat.st_page_create; - } else { - ++dbmp->mp->stat.st_page_in; - ++mfp->stat.st_page_in; - } - } - - 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_IO db_io; - DB_LOG *lg_info; - DB_LSN lsn; - DB_MPOOL *dbmp; - MPOOL *mp; - MPOOLFILE *mfp; - ssize_t nw; - int callpgin, ret, syncfail; - const char *fail; - - dbmp = dbmfp->dbmp; - dbenv = dbmp->dbenv; - mp = dbmp->mp; - mfp = dbmfp->mfp; - - if (restartp != NULL) - *restartp = 0; - if (wrotep != NULL) - *wrotep = 0; - callpgin = 0; - - /* - * Check the dirty bit -- this buffer may have been written since we - * decided to write it. - */ - if (!F_ISSET(bhp, BH_DIRTY)) { - if (wrotep != NULL) - *wrotep = 1; - return (0); - } - - LOCKBUFFER(dbmp, bhp); - - /* - * If there were two writers, we may have just been waiting while the - * other writer completed I/O on this buffer. Check the dirty bit one - * more time. - */ - if (!F_ISSET(bhp, BH_DIRTY)) { - UNLOCKBUFFER(dbmp, bhp); - - if (wrotep != NULL) - *wrotep = 1; - return (0); - } - - F_SET(bhp, BH_LOCKED); - 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 we flag - * that the contents of the buffer will need to be passed through pgin - * before they are reused. - */ - 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. */ - if (dbmfp->fd == -1) { - LOCKHANDLE(dbmp, dbmfp->mutexp); - if (dbmfp->fd == -1 && ((ret = __db_appname(dbenv, - DB_APP_TMP, NULL, NULL, DB_CREATE | DB_EXCL | DB_TEMPORARY, - &dbmfp->fd, NULL)) != 0 || dbmfp->fd == -1)) { - UNLOCKHANDLE(dbmp, dbmfp->mutexp); - __db_err(dbenv, - "unable to create temporary backing file"); - goto err; - } - UNLOCKHANDLE(dbmp, dbmfp->mutexp); - } - - /* Write the page. */ - db_io.fd_io = dbmfp->fd; - db_io.fd_lock = dbmp->reginfo.fd; - db_io.mutexp = F_ISSET(dbmp, MP_LOCKHANDLE) ? dbmfp->mutexp : NULL; - db_io.pagesize = db_io.bytes = mfp->stat.st_pagesize; - db_io.pgno = bhp->pgno; - db_io.buf = bhp->buf; - if ((ret = __os_io(&db_io, DB_IO_WRITE, &nw)) != 0) { - __db_panic(dbenv, ret); - fail = "write"; - goto syserr; - } - if (nw != (ssize_t)mfp->stat.st_pagesize) { - ret = EIO; - fail = "write"; - goto syserr; - } - - if (wrotep != NULL) - *wrotep = 1; - - /* Unlock the buffer and reacquire the region lock. */ - UNLOCKBUFFER(dbmp, bhp); - LOCKREGION(dbmp); - - /* - * Clean up the flags based on a successful write. - * - * If we rewrote the page, it will need processing by the pgin - * routine before reuse. - */ - if (callpgin) - F_SET(bhp, BH_CALLPGIN); - F_CLR(bhp, BH_DIRTY | BH_LOCKED); - - /* - * If we write a buffer for which a checkpoint is waiting, 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: - * Don't lock the region around the sync, fsync(2) has no atomicity - * issues. - * - * 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 checkpoint - * to be retried later. - */ - if (F_ISSET(bhp, BH_WRITE)) { - if (mfp->lsn_cnt == 1) { - UNLOCKREGION(dbmp); - syncfail = __os_fsync(dbmfp->fd) != 0; - LOCKREGION(dbmp); - if (syncfail) - F_SET(mp, MP_LSN_RETRY); - - } - - F_CLR(bhp, BH_WRITE); - - /* - * If the buffer just written has a larger LSN than the current - * max LSN written for this checkpoint, update the saved value. - */ - if (log_compare(&lsn, &mp->lsn) > 0) - mp->lsn = lsn; - - --mp->lsn_cnt; - --mfp->lsn_cnt; - } - - /* Update the page clean/dirty statistics. */ - ++mp->stat.st_page_clean; - --mp->stat.st_page_dirty; - - /* 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", - __memp_fn(dbmfp), fail, (u_long)bhp->pgno); - -err: /* Unlock the buffer and reacquire the region lock. */ - UNLOCKBUFFER(dbmp, bhp); - LOCKREGION(dbmp); - - /* - * Clean up the flags based on a failure. - * - * The page remains dirty but we remove our lock. If we rewrote the - * page, it will need processing by the pgin routine before reuse. - */ - 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->mutexp); - - 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 = R_ADDR(dbmp, mfp->pgcookie_off); - dbtp = &dbt; - } - UNLOCKHANDLE(dbmp, dbmp->mutexp); - - 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->mutexp); - - return (0); - -err: UNLOCKHANDLE(dbmp, dbmp->mutexp); - __db_err(dbmp->dbenv, "%s: %s failed for page %lu", - __memp_fn(dbmfp), 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 hash bucket queue. */ - off = BUCKET(dbmp->mp, R_OFFSET(dbmp, mfp), bhp->pgno); - SH_TAILQ_REMOVE(&dbmp->htab[off], bhp, hq, __bh); - - /* Delete the buffer header from the LRU queue. */ - 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); - --dbmp->mp->stat.st_page_clean; - } -} - -/* - * __memp_upgrade -- - * Upgrade a file descriptor from readonly to readwrite. - */ -static int -__memp_upgrade(dbmp, dbmfp, mfp) - DB_MPOOL *dbmp; - DB_MPOOLFILE *dbmfp; - MPOOLFILE *mfp; -{ - int fd, ret; - char *rpath; - - /* - * !!! - * We expect the handle to already be locked. - */ - - /* Check to see if we've already upgraded. */ - if (F_ISSET(dbmfp, MP_UPGRADE)) - return (0); - - /* Check to see if we've already failed. */ - if (F_ISSET(dbmfp, MP_UPGRADE_FAIL)) - return (1); - - /* - * Calculate the real name for this file and try to open it read/write. - * We know we have a valid pathname for the file because it's the only - * way we could have gotten a file descriptor of any kind. - */ - if ((ret = __db_appname(dbmp->dbenv, DB_APP_DATA, - NULL, R_ADDR(dbmp, mfp->path_off), 0, NULL, &rpath)) != 0) - return (ret); - if (__db_open(rpath, 0, 0, 0, &fd) != 0) { - F_SET(dbmfp, MP_UPGRADE_FAIL); - ret = 1; - } else { - /* Swap the descriptors and set the upgrade flag. */ - (void)__os_close(dbmfp->fd); - dbmfp->fd = fd; - F_SET(dbmfp, MP_UPGRADE); - ret = 0; - } - __os_freestr(rpath); - return (ret); -} |