/*- * See the file LICENSE for redistribution information. * * Copyright (c) 1996-2005 * Sleepycat Software. All rights reserved. * * $Id: mp_sync.c,v 12.11 2005/10/07 20:21:33 ubell Exp $ */ #include "db_config.h" #ifndef NO_SYSTEM_INCLUDES #include #include #endif #include "db_int.h" #include "dbinc/db_shash.h" #include "dbinc/log.h" #include "dbinc/mp.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((DB_ENV *, DB_MPOOL *, int)); static int __memp_sync_files __P((DB_ENV *, DB_MPOOL *)); /* * __memp_sync_pp -- * DB_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; int ret; PANIC_CHECK(dbenv); ENV_REQUIRES_CONFIG(dbenv, dbenv->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(dbenv, dbenv->lg_handle, "memp_sync", DB_INIT_LOG); ENV_ENTER(dbenv, ip); REPLICATION_WRAP(dbenv, (__memp_sync(dbenv, lsnp)), ret); ENV_LEAVE(dbenv, ip); return (ret); } /* * __memp_sync -- * DB_ENV->memp_sync. * * PUBLIC: int __memp_sync __P((DB_ENV *, DB_LSN *)); */ int __memp_sync(dbenv, lsnp) DB_ENV *dbenv; DB_LSN *lsnp; { DB_MPOOL *dbmp; MPOOL *mp; int ret; dbmp = dbenv->mp_handle; mp = dbmp->reginfo[0].primary; /* If we've flushed to the requested LSN, return that information. */ if (lsnp != NULL) { MPOOL_SYSTEM_LOCK(dbenv); if (log_compare(lsnp, &mp->lsn) <= 0) { *lsnp = mp->lsn; MPOOL_SYSTEM_UNLOCK(dbenv); return (0); } MPOOL_SYSTEM_UNLOCK(dbenv); } if ((ret = __memp_sync_int(dbenv, NULL, 0, DB_SYNC_CACHE, NULL)) != 0) return (ret); if (lsnp != NULL) { MPOOL_SYSTEM_LOCK(dbenv); if (log_compare(lsnp, &mp->lsn) > 0) mp->lsn = *lsnp; MPOOL_SYSTEM_UNLOCK(dbenv); } 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_ENV *dbenv; DB_THREAD_INFO *ip; int ret; dbenv = dbmfp->dbenv; PANIC_CHECK(dbenv); MPF_ILLEGAL_BEFORE_OPEN(dbmfp, "DB_MPOOLFILE->sync"); ENV_ENTER(dbenv, ip); REPLICATION_WRAP(dbenv, (__memp_fsync(dbmfp)), ret); ENV_LEAVE(dbenv, 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->dbenv, dbmfp, 0, DB_SYNC_FILE, 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; { /* * 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); return (__memp_sync_int(dbmfp->dbenv, dbmfp, 0, DB_SYNC_FILE, NULL)); } /* * __memp_sync_int -- * Mpool sync internal function. * * PUBLIC: int __memp_sync_int __P((DB_ENV *, * PUBLIC: DB_MPOOLFILE *, u_int32_t, db_sync_op, u_int32_t *)); */ int __memp_sync_int(dbenv, dbmfp, trickle_max, op, wrotep) DB_ENV *dbenv; DB_MPOOLFILE *dbmfp; u_int32_t trickle_max, *wrotep; db_sync_op op; { 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; int filecnt, hb_lock, maxopenfd, maxwrite, maxwrite_sleep; int pass, ret, t_ret, wait_cnt, write_cnt; dbmp = dbenv->mp_handle; mp = dbmp->reginfo[0].primary; last_mf_offset = INVALID_ROFF; filecnt = pass = wrote = 0; /* Get shared configuration information. */ MPOOL_SYSTEM_LOCK(dbenv); maxopenfd = mp->mp_maxopenfd; maxwrite = mp->mp_maxwrite; maxwrite_sleep = mp->mp_maxwrite_sleep; MPOOL_SYSTEM_UNLOCK(dbenv); /* Assume one dirty page per bucket. */ ar_max = mp->nreg * mp->htab_buckets; if ((ret = __os_malloc(dbenv, 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 pinned 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 buckets because we only need write * buffers that were dirty before we started. */ if (SH_TAILQ_FIRST(&hp->hash_bucket, __bh) == NULL) continue; MUTEX_LOCK(dbenv, hp->mtx_hash); for (bhp = SH_TAILQ_FIRST(&hp->hash_bucket, __bh); bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, hq, __bh)) { /* Always ignore unreferenced, clean pages. */ if (bhp->ref == 0 && !F_ISSET(bhp, BH_DIRTY)) continue; /* * Checkpoints have to wait on all pinned pages, * as pages may be marked dirty when returned to * the cache. * * File syncs only wait on pages both pinned and * dirty. (We don't care if pages are marked * dirty when returned to the cache, that means * there's another writing thread and flushing * the cache for this handle is meaningless.) */ if (op == DB_SYNC_FILE && !F_ISSET(bhp, BH_DIRTY)) continue; mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset); /* * Ignore in-memory files, even if they are * temp files to whom a backing file has been * allocated. */ if (mfp->no_backing_file || F_ISSET(mfp, MP_TEMP)) continue; /* * If we're flushing a specific file, see if * this page is from that file. */ if (dbmfp != NULL && mfp != dbmfp->mfp) continue; /* * Ignore files that aren't involved in DB's * transactional operations during checkpoints. */ if (dbmfp == NULL && mfp->lsn_off == -1) 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(dbenv, (ar_max * 2) * sizeof(BH_TRACK), &bharray)) != 0) break; ar_max *= 2; } } MUTEX_UNLOCK(dbenv, hp->mtx_hash); if (ret != 0) 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 (op == 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(dbenv) && (ret = __log_flush(dbenv, 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 = pass = write_cnt = 0, remaining = ar_cnt; remaining > 0; ++i) { if (i >= ar_cnt) { i = 0; ++pass; __os_sleep(dbenv, 1, 0); } if ((hp = bharray[i].track_hp) == NULL) continue; /* Lock the hash bucket and find the buffer. */ mutex = hp->mtx_hash; MUTEX_LOCK(dbenv, mutex); for (bhp = SH_TAILQ_FIRST(&hp->hash_bucket, __bh); bhp != NULL; bhp = SH_TAILQ_NEXT(bhp, 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 pinned or dirty, we're done, there's * no work needed. */ if (bhp == NULL || (bhp->ref == 0 && !F_ISSET(bhp, BH_DIRTY))) { MUTEX_UNLOCK(dbenv, 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 the buffer is pinned and it's only the first or second * time we have looked at it, ignore it, we'll come back to * it. * * In either case, skip the buffer if we're not required to * write it. */ if (F_ISSET(bhp, BH_LOCKED) || (bhp->ref != 0 && pass < 2)) { MUTEX_UNLOCK(dbenv, mutex); if (op != DB_SYNC_CACHE && op != DB_SYNC_FILE) { --remaining; bharray[i].track_hp = NULL; } continue; } /* * The buffer is either pinned or dirty. * * Set the sync wait-for count, used to count down outstanding * references to this buffer as they are returned to the cache. */ bhp->ref_sync = bhp->ref; /* Pin the buffer into memory and lock it. */ ++bhp->ref; F_SET(bhp, BH_LOCKED); MUTEX_LOCK(dbenv, bhp->mtx_bh); /* * Unlock the hash bucket and wait for the wait-for count to * go to 0. No new thread can acquire the buffer because we * have it locked. * * If a thread attempts to re-pin a page, the wait-for count * will never go to 0 (the thread spins on our buffer lock, * while we spin on the thread's ref count). Give up if we * don't get the buffer in 3 seconds, we can try again later. * * If, when the wait-for count goes to 0, the buffer is found * to be dirty, write it. */ MUTEX_UNLOCK(dbenv, mutex); for (wait_cnt = 1; bhp->ref_sync != 0 && wait_cnt < 4; ++wait_cnt) __os_sleep(dbenv, 1, 0); MUTEX_LOCK(dbenv, mutex); hb_lock = 1; /* * 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 ((ret = __memp_close_flush_files( dbenv, dbmp, 1)) != 0) break; } last_mf_offset = bhp->mf_offset; } /* * If the ref_sync count has gone to 0, we're going to be done * with this buffer no matter what happens. */ if (bhp->ref_sync == 0) { --remaining; bharray[i].track_hp = NULL; } /* * If the ref_sync count has gone to 0 and the buffer is still * dirty, we write it. We only try to write the buffer once. */ if (bhp->ref_sync == 0 && F_ISSET(bhp, BH_DIRTY)) { hb_lock = 0; MUTEX_UNLOCK(dbenv, mutex); mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset); if ((ret = __memp_bhwrite(dbmp, hp, mfp, bhp, 1)) == 0) ++wrote; else __db_err(dbenv, "%s: unable to flush page: %lu", __memp_fns(dbmp, mfp), (u_long)bhp->pgno); /* * Avoid saturating the disk, sleep once we've done * some number of writes. */ if (maxwrite != 0 && ++write_cnt >= maxwrite) { write_cnt = 0; __os_sleep(dbenv, 0, (u_long)maxwrite_sleep); } } /* * If ref_sync count never went to 0, the buffer was written * by another thread, or the write failed, we still have the * buffer locked. * * We may or may not currently hold the hash bucket mutex. If * the __memp_bhwrite -> __memp_pgwrite call was successful, * then __memp_pgwrite will have swapped the buffer lock for * the hash lock. All other call paths will leave us without * the hash bucket lock. * * The order of mutexes above was to acquire the buffer lock * while holding the hash bucket lock. Don't deadlock here, * release the buffer lock and then acquire the hash bucket * lock. */ if (F_ISSET(bhp, BH_LOCKED)) { F_CLR(bhp, BH_LOCKED); MUTEX_UNLOCK(dbenv, bhp->mtx_bh); if (!hb_lock) MUTEX_LOCK(dbenv, mutex); } /* * Reset the ref_sync count regardless of our success, we're * done with this buffer for now. */ bhp->ref_sync = 0; /* Discard our reference and unlock the bucket. */ --bhp->ref; MUTEX_UNLOCK(dbenv, mutex); if (ret != 0) break; } done: /* * If doing a checkpoint or flushing a file for the application, 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 && (op == DB_SYNC_CACHE || op == DB_SYNC_FILE)) { if (dbmfp == NULL) ret = __memp_sync_files(dbenv, dbmp); else ret = __os_fsync(dbenv, dbmfp->fhp); } /* If we've opened files to flush pages, close them. */ if ((t_ret = __memp_close_flush_files(dbenv, dbmp, 0)) != 0 && ret == 0) ret = t_ret; err: __os_free(dbenv, bharray); if (wrotep != NULL) *wrotep = wrote; return (ret); } /* * __memp_sync_files -- * Sync all the files in the environment, open or not. */ static int __memp_sync_files(dbenv, dbmp) DB_ENV *dbenv; DB_MPOOL *dbmp; { DB_MPOOLFILE *dbmfp; MPOOL *mp; MPOOLFILE *mfp, *next_mfp; int need_discard_pass, ret, t_ret; need_discard_pass = ret = 0; mp = dbmp->reginfo[0].primary; MPOOL_SYSTEM_LOCK(dbenv); for (mfp = SH_TAILQ_FIRST(&mp->mpfq, __mpoolfile); mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile)) { if (!mfp->file_written || mfp->no_backing_file || mfp->deadfile || F_ISSET(mfp, MP_TEMP)) continue; /* * 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(dbenv, mfp->mutex); if (!mfp->file_written || mfp->deadfile) { MUTEX_UNLOCK(dbenv, mfp->mutex); continue; } MPOOL_SYSTEM_UNLOCK(dbenv); ++mfp->mpf_cnt; MUTEX_UNLOCK(dbenv, mfp->mutex); /* * Look for an already open, writeable handle (fsync doesn't * work on read-only Windows handles). */ MUTEX_LOCK(dbenv, dbmp->mutex); for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq); dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, 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(dbenv, dbmp->mutex); /* If we don't find a handle we can use, open one. */ if (dbmfp == NULL) { if ((t_ret = __memp_mf_sync(dbmp, mfp, 0)) != 0) { __db_err(dbenv, "%s: unable to flush: %s", (char *) R_ADDR(dbmp->reginfo, mfp->path_off), db_strerror(t_ret)); if (ret == 0) ret = t_ret; } } else { if ((t_ret = __os_fsync(dbenv, dbmfp->fhp)) != 0 && ret == 0) ret = t_ret; if ((t_ret = __memp_fclose(dbmfp, 0)) != 0 && ret == 0) ret = t_ret; } /* * Re-acquire the region lock, we need it to move to the next * MPOOLFILE. * * Re-acquire the MPOOLFILE mutex, we need it to modify the * reference count. */ MPOOL_SYSTEM_LOCK(dbenv); MUTEX_LOCK(dbenv, mfp->mutex); --mfp->mpf_cnt; /* * If we wrote the file and there are no open handles (or there * is a single open handle, 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 == 0 || (mfp->mpf_cnt == 1 && 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 == 0 && mfp->block_cnt == 0) need_discard_pass = 1; } /* Unlock the MPOOLFILE, and move to the next entry. */ MUTEX_UNLOCK(dbenv, mfp->mutex); } /* * We exit the loop holding the region lock. * * 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) for (mfp = SH_TAILQ_FIRST( &mp->mpfq, __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->block_cnt != 0 || mfp->mpf_cnt != 0) continue; MUTEX_LOCK(dbenv, mfp->mutex); if (mfp->block_cnt == 0 && mfp->mpf_cnt == 0) (void)__memp_mf_discard(dbmp, mfp); else MUTEX_UNLOCK(dbenv, mfp->mutex); } MPOOL_SYSTEM_UNLOCK(dbenv); 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, region_locked) DB_MPOOL *dbmp; MPOOLFILE *mfp; int region_locked; { DB_ENV *dbenv; DB_FH *fhp; int ret, t_ret; char *rpath; dbenv = dbmp->dbenv; /* * We need to be holding the region lock: we're using the path name * and __memp_nameop might try and rename the file. */ if (!region_locked) MPOOL_SYSTEM_LOCK(dbenv); if ((ret = __db_appname(dbenv, DB_APP_DATA, R_ADDR(dbmp->reginfo, mfp->path_off), 0, NULL, &rpath)) == 0) { if ((ret = __os_open(dbenv, rpath, 0, 0, &fhp)) == 0) { ret = __os_fsync(dbenv, fhp); if ((t_ret = __os_closehandle(dbenv, fhp)) != 0 && ret == 0) ret = t_ret; } __os_free(dbenv, rpath); } if (!region_locked) MPOOL_SYSTEM_UNLOCK(dbenv); return (ret); } /* * __memp_close_flush_files -- * Close files opened only to flush buffers. */ static int __memp_close_flush_files(dbenv, dbmp, dosync) DB_ENV *dbenv; DB_MPOOL *dbmp; int dosync; { DB_MPOOLFILE *dbmfp; MPOOLFILE *mfp; int ret; /* * 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(dbenv, dbmp->mutex); for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq); dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q)) if (F_ISSET(dbmfp, MP_FLUSH)) { F_CLR(dbmfp, MP_FLUSH); MUTEX_UNLOCK(dbenv, 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(dbenv, mfp->mutex); if (mfp->mpf_cnt == 1) mfp->file_written = 0; MUTEX_UNLOCK(dbenv, mfp->mutex); } if ((ret = __os_fsync(dbenv, dbmfp->fhp)) != 0) return (ret); } if ((ret = __memp_fclose(dbmfp, 0)) != 0) return (ret); goto retry; } MUTEX_UNLOCK(dbenv, 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); }