diff options
Diffstat (limited to 'storage/bdb/mp/mp_sync.c')
| -rw-r--r-- | storage/bdb/mp/mp_sync.c | 627 |
1 files changed, 627 insertions, 0 deletions
diff --git a/storage/bdb/mp/mp_sync.c b/storage/bdb/mp/mp_sync.c new file mode 100644 index 00000000000..03b42208b39 --- /dev/null +++ b/storage/bdb/mp/mp_sync.c @@ -0,0 +1,627 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 1996-2002 + * Sleepycat Software. All rights reserved. + */ +#include "db_config.h" + +#ifndef lint +static const char revid[] = "$Id: mp_sync.c,v 11.64 2002/08/25 16:00:27 bostic Exp $"; +#endif /* not lint */ + +#ifndef NO_SYSTEM_INCLUDES +#include <sys/types.h> + +#include <stdlib.h> +#endif + +#include "db_int.h" +#include "dbinc/db_shash.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 *)); +static int __memp_sync_files __P((DB_ENV *, DB_MPOOL *)); + +/* + * __memp_sync -- + * Mpool sync function. + * + * 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; + + 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); + + dbmp = dbenv->mp_handle; + mp = dbmp->reginfo[0].primary; + + /* If we've flushed to the requested LSN, return that information. */ + if (lsnp != NULL) { + R_LOCK(dbenv, dbmp->reginfo); + if (log_compare(lsnp, &mp->lsn) <= 0) { + *lsnp = mp->lsn; + + R_UNLOCK(dbenv, dbmp->reginfo); + return (0); + } + R_UNLOCK(dbenv, dbmp->reginfo); + } + + if ((ret = __memp_sync_int(dbenv, NULL, 0, DB_SYNC_CACHE, NULL)) != 0) + return (ret); + + if (lsnp != NULL) { + R_LOCK(dbenv, dbmp->reginfo); + if (log_compare(lsnp, &mp->lsn) > 0) + mp->lsn = *lsnp; + R_UNLOCK(dbenv, dbmp->reginfo); + } + + return (0); +} + +/* + * __memp_fsync -- + * Mpool file sync function. + * + * PUBLIC: int __memp_fsync __P((DB_MPOOLFILE *)); + */ +int +__memp_fsync(dbmfp) + DB_MPOOLFILE *dbmfp; +{ + DB_ENV *dbenv; + DB_MPOOL *dbmp; + + dbmp = dbmfp->dbmp; + dbenv = dbmp->dbenv; + + PANIC_CHECK(dbenv); + + /* + * If this handle doesn't have a file descriptor that's open for + * writing, or if the file is a temporary, there's no reason to + * proceed further. + */ + if (F_ISSET(dbmfp, MP_READONLY)) + return (0); + + if (F_ISSET(dbmfp->mfp, MP_TEMP)) + return (0); + + return (__memp_sync_int(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; +{ + DB_ENV *dbenv; + /* + * 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. + */ + *fhp = dbmfp->fhp; + if (F_ISSET(dbmfp->fhp, DB_FH_VALID)) + return (0); + dbenv = dbmfp->dbmp->dbenv; + + return (__memp_sync_int(dbenv, dbmfp, 0, DB_SYNC_FILE, NULL)); +} + +/* + * __memp_sync_int -- + * Mpool sync internal function. + * + * PUBLIC: int __memp_sync_int + * PUBLIC: __P((DB_ENV *, DB_MPOOLFILE *, int, db_sync_op, int *)); + */ +int +__memp_sync_int(dbenv, dbmfp, ar_max, op, wrotep) + DB_ENV *dbenv; + DB_MPOOLFILE *dbmfp; + int ar_max, *wrotep; + db_sync_op op; +{ + BH *bhp; + BH_TRACK *bharray; + DB_MPOOL *dbmp; + DB_MPOOL_HASH *hp; + DB_MUTEX *mutexp; + MPOOL *c_mp, *mp; + MPOOLFILE *mfp; + u_int32_t n_cache; + int ar_cnt, hb_lock, i, pass, remaining, ret, t_ret, wait_cnt, wrote; + + dbmp = dbenv->mp_handle; + mp = dbmp->reginfo[0].primary; + pass = wrote = 0; + + /* + * If the caller does not specify how many pages assume one + * per bucket. + */ + if (ar_max == 0) + 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->hash_mutex); + 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 temporary files -- this means you + * can't even flush temporary files by handle. + * (Checkpoint doesn't require temporary files + * be flushed and the underlying buffer write + * write routine may not be able to write it + * anyway.) + */ + if (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 (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->hash_mutex); + + 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 for this region. We may not write enough if the dirty + * buffers have an unbalanced distribution among the regions, but that + * seems unlikely. + */ + if (op == DB_SYNC_TRICKLE && ar_cnt > ar_max / (int)mp->nreg) + ar_cnt = ar_max / (int)mp->nreg; + + /* + * 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 = dbenv->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 (remaining = ar_cnt, i = pass = 0; 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. */ + mutexp = &hp->hash_mutex; + MUTEX_LOCK(dbenv, mutexp); + 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, mutexp); + --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, mutexp); + 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->mutex); + + /* + * 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, mutexp); + for (wait_cnt = 1; + bhp->ref_sync != 0 && wait_cnt < 4; ++wait_cnt) + __os_sleep(dbenv, 1, 0); + MUTEX_LOCK(dbenv, mutexp); + hb_lock = 1; + + /* + * 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. + * Any process checkpointing or trickle-flushing the pool + * must be able to write any underlying file -- if the write + * fails, error out. It would be very strange if file sync + * failed to write, but we don't care if it happens. + */ + if (bhp->ref_sync == 0 && F_ISSET(bhp, BH_DIRTY)) { + hb_lock = 0; + MUTEX_UNLOCK(dbenv, mutexp); + + mfp = R_ADDR(dbmp->reginfo, bhp->mf_offset); + if ((ret = __memp_bhwrite(dbmp, hp, mfp, bhp, 1)) == 0) + ++wrote; + else if (op == DB_SYNC_CACHE || op == DB_SYNC_TRICKLE) + __db_err(dbenv, "%s: unable to flush page: %lu", + __memp_fns(dbmp, mfp), (u_long)bhp->pgno); + else + ret = 0; + } + + /* + * 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->mutex); + + if (!hb_lock) + MUTEX_LOCK(dbenv, mutexp); + } + + /* + * 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, mutexp); + + if (ret != 0) + break; + } + +done: /* If we've opened files to flush pages, close them. */ + if ((t_ret = __memp_close_flush_files(dbenv, dbmp)) != 0 && ret == 0) + ret = t_ret; + + /* + * 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); + } + +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; + int ret, t_ret; + + ret = 0; + mp = dbmp->reginfo[0].primary; + + R_LOCK(dbenv, dbmp->reginfo); + for (mfp = SH_TAILQ_FIRST(&mp->mpfq, __mpoolfile); + mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile)) { + if (mfp->stat.st_page_out == 0 || + F_ISSET(mfp, MP_DEADFILE | MP_TEMP)) + continue; + + /* Look for an already open handle. */ + ret = 0; + MUTEX_THREAD_LOCK(dbenv, dbmp->mutexp); + for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq); + dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q)) + if (dbmfp->mfp == mfp) { + ret = __os_fsync(dbenv, dbmfp->fhp); + break; + } + MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp); + if (ret != 0) + goto err; + + /* If we don't find one, open one. */ + if (dbmfp == NULL) { + if ((ret = dbenv->memp_fcreate(dbenv, &dbmfp, 0)) != 0) + goto err; + ret = __memp_fopen_int( + dbmfp, mfp, R_ADDR(dbmp->reginfo, mfp->path_off), + 0, 0, mfp->stat.st_pagesize); + if (ret == 0) + ret = __os_fsync(dbenv, dbmfp->fhp); + if ((t_ret = + __memp_fclose_int(dbmfp, 0)) != 0 && ret == 0) + ret = t_ret; + if (ret != 0) + goto err; + } + } + + if (0) { +err: __db_err(dbenv, "%s: cannot sync: %s", + R_ADDR(dbmp->reginfo, mfp->path_off), db_strerror(ret)); + } + R_UNLOCK(dbenv, dbmp->reginfo); + + return (ret); +} + +/* + * __memp_close_flush_files -- + * Close files opened only to flush buffers. + */ +static int +__memp_close_flush_files(dbenv, dbmp) + DB_ENV *dbenv; + DB_MPOOL *dbmp; +{ + DB_MPOOLFILE *dbmfp; + 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, and 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_THREAD_LOCK(dbenv, dbmp->mutexp); + 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_THREAD_UNLOCK(dbenv, dbmp->mutexp); + if ((ret = __memp_fclose_int(dbmfp, 0)) != 0) + return (ret); + goto retry; + } + MUTEX_THREAD_UNLOCK(dbenv, dbmp->mutexp); + + 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); +} |