566 lines
13 KiB
C
566 lines
13 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 1996, 1997
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* Sleepycat Software. All rights reserved.
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*/
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#include "config.h"
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#ifndef lint
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static const char sccsid[] = "@(#)mp_bh.c 10.28 (Sleepycat) 1/8/98";
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#endif /* not lint */
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#ifndef NO_SYSTEM_INCLUDES
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#include <sys/types.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#endif
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#include "db_int.h"
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#include "shqueue.h"
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#include "db_shash.h"
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#include "mp.h"
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#include "common_ext.h"
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static int __memp_upgrade __P((DB_MPOOL *, DB_MPOOLFILE *, MPOOLFILE *));
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/*
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* __memp_bhwrite --
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* Write the page associated with a given bucket header.
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*
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* PUBLIC: int __memp_bhwrite
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* PUBLIC: __P((DB_MPOOL *, MPOOLFILE *, BH *, int *, int *));
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*/
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int
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__memp_bhwrite(dbmp, mfp, bhp, restartp, wrotep)
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DB_MPOOL *dbmp;
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MPOOLFILE *mfp;
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BH *bhp;
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int *restartp, *wrotep;
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{
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DB_MPOOLFILE *dbmfp;
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DB_MPREG *mpreg;
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if (restartp != NULL)
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*restartp = 0;
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if (wrotep != NULL)
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*wrotep = 0;
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/*
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* Walk the process' DB_MPOOLFILE list and find a file descriptor for
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* the file. We also check that the descriptor is open for writing.
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* If we find a descriptor on the file that's not open for writing, we
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* try and upgrade it to make it writeable. If that fails, we're done.
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*/
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LOCKHANDLE(dbmp, dbmp->mutexp);
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for (dbmfp = TAILQ_FIRST(&dbmp->dbmfq);
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dbmfp != NULL; dbmfp = TAILQ_NEXT(dbmfp, q))
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if (dbmfp->mfp == mfp) {
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if (F_ISSET(dbmfp, MP_READONLY) &&
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__memp_upgrade(dbmp, dbmfp, mfp))
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return (0);
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break;
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}
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UNLOCKHANDLE(dbmp, dbmp->mutexp);
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if (dbmfp != NULL)
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goto found;
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/*
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* It's not a page from a file we've opened. If the file requires
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* input/output processing, see if this process has ever registered
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* information as to how to write this type of file. If not, there's
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* nothing we can do.
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*/
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if (mfp->ftype != 0) {
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LOCKHANDLE(dbmp, dbmp->mutexp);
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for (mpreg = LIST_FIRST(&dbmp->dbregq);
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mpreg != NULL; mpreg = LIST_NEXT(mpreg, q))
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if (mpreg->ftype == mfp->ftype)
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break;
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UNLOCKHANDLE(dbmp, dbmp->mutexp);
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if (mpreg == NULL)
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return (0);
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}
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/*
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* Try and open the file, attaching to the underlying shared area.
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*
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* XXX
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* Don't try to attach to temporary files. There are two problems in
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* trying to do that. First, if we have different privileges than the
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* process that "owns" the temporary file, we might create the backing
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* disk file such that the owning process couldn't read/write its own
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* buffers, e.g., memp_trickle() running as root creating a file owned
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* as root, mode 600. Second, if the temporary file has already been
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* created, we don't have any way of finding out what its real name is,
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* and, even if we did, it was already unlinked (so that it won't be
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* left if the process dies horribly). This decision causes a problem,
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* however: if the temporary file consumes the entire buffer cache,
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* and the owner doesn't flush the buffers to disk, we could end up
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* with resource starvation, and the memp_trickle() thread couldn't do
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* anything about it. That's a pretty unlikely scenario, though.
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*
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* XXX
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* There's no negative cache, so we may repeatedly try and open files
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* that we have previously tried (and failed) to open.
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*
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* Ignore any error, assume it's a permissions problem.
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*/
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if (F_ISSET(mfp, MP_TEMP))
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return (0);
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if (__memp_fopen(dbmp, mfp, R_ADDR(dbmp, mfp->path_off), mfp->ftype,
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0, 0, mfp->stat.st_pagesize, 0, NULL, NULL, 0, &dbmfp) != 0)
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return (0);
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found: return (__memp_pgwrite(dbmfp, bhp, restartp, wrotep));
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}
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/*
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* __memp_pgread --
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* Read a page from a file.
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*
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* PUBLIC: int __memp_pgread __P((DB_MPOOLFILE *, BH *, int));
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*/
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int
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__memp_pgread(dbmfp, bhp, can_create)
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DB_MPOOLFILE *dbmfp;
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BH *bhp;
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int can_create;
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{
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DB_MPOOL *dbmp;
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MPOOLFILE *mfp;
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size_t pagesize;
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ssize_t nr;
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int ret;
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dbmp = dbmfp->dbmp;
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mfp = dbmfp->mfp;
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pagesize = mfp->stat.st_pagesize;
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F_SET(bhp, BH_LOCKED | BH_TRASH);
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LOCKBUFFER(dbmp, bhp);
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UNLOCKREGION(dbmp);
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/*
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* Temporary files may not yet have been created.
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*
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* Seek to the page location.
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*/
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ret = 0;
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LOCKHANDLE(dbmp, dbmfp->mutexp);
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if (dbmfp->fd == -1 || (ret =
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__db_seek(dbmfp->fd, pagesize, bhp->pgno, 0, SEEK_SET)) != 0) {
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if (!can_create) {
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if (dbmfp->fd == -1)
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ret = EINVAL;
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UNLOCKHANDLE(dbmp, dbmfp->mutexp);
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__db_err(dbmp->dbenv,
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"%s: page %lu doesn't exist, create flag not set",
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__memp_fn(dbmfp), (u_long)bhp->pgno);
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goto err;
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}
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UNLOCKHANDLE(dbmp, dbmfp->mutexp);
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/* Clear any uninitialized data. */
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memset(bhp->buf, 0, pagesize);
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goto pgin;
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}
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/*
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* Read the page; short reads are treated like creates, although
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* any valid data is preserved.
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*/
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ret = __db_read(dbmfp->fd, bhp->buf, pagesize, &nr);
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UNLOCKHANDLE(dbmp, dbmfp->mutexp);
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if (ret != 0)
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goto err;
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if (nr == (ssize_t)pagesize)
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can_create = 0;
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else {
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if (!can_create) {
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ret = EINVAL;
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goto err;
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}
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/* Clear any uninitialized data. */
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memset(bhp->buf + nr, 0, pagesize - nr);
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}
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/* Call any pgin function. */
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pgin: ret = mfp->ftype == 0 ? 0 : __memp_pg(dbmfp, bhp, 1);
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/* Unlock the buffer and reacquire the region lock. */
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err: UNLOCKBUFFER(dbmp, bhp);
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LOCKREGION(dbmp);
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/*
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* If no errors occurred, the data is now valid, clear the BH_TRASH
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* flag; regardless, clear the lock bit and let other threads proceed.
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*/
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F_CLR(bhp, BH_LOCKED);
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if (ret == 0) {
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F_CLR(bhp, BH_TRASH);
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/* Update the statistics. */
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if (can_create) {
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++dbmp->mp->stat.st_page_create;
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++mfp->stat.st_page_create;
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} else {
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++dbmp->mp->stat.st_page_in;
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++mfp->stat.st_page_in;
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}
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}
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return (ret);
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}
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/*
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* __memp_pgwrite --
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* Write a page to a file.
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*
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* PUBLIC: int __memp_pgwrite __P((DB_MPOOLFILE *, BH *, int *, int *));
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*/
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int
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__memp_pgwrite(dbmfp, bhp, restartp, wrotep)
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DB_MPOOLFILE *dbmfp;
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BH *bhp;
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int *restartp, *wrotep;
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{
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DB_ENV *dbenv;
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DB_LOG *lg_info;
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DB_LSN lsn;
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DB_MPOOL *dbmp;
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MPOOL *mp;
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MPOOLFILE *mfp;
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size_t pagesize;
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ssize_t nw;
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int callpgin, ret, syncfail;
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const char *fail;
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dbmp = dbmfp->dbmp;
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dbenv = dbmp->dbenv;
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mp = dbmp->mp;
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mfp = dbmfp->mfp;
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if (restartp != NULL)
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*restartp = 0;
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if (wrotep != NULL)
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*wrotep = 0;
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callpgin = 0;
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pagesize = mfp->stat.st_pagesize;
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/*
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* Check the dirty bit -- this buffer may have been written since we
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* decided to write it.
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*/
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if (!F_ISSET(bhp, BH_DIRTY)) {
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if (wrotep != NULL)
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*wrotep = 1;
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return (0);
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}
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LOCKBUFFER(dbmp, bhp);
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/*
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* If there were two writers, we may have just been waiting while the
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* other writer completed I/O on this buffer. Check the dirty bit one
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* more time.
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*/
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if (!F_ISSET(bhp, BH_DIRTY)) {
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UNLOCKBUFFER(dbmp, bhp);
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if (wrotep != NULL)
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*wrotep = 1;
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return (0);
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}
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F_SET(bhp, BH_LOCKED);
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UNLOCKREGION(dbmp);
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if (restartp != NULL)
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*restartp = 1;
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/* Copy the LSN off the page if we're going to need it. */
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lg_info = dbenv->lg_info;
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if (lg_info != NULL || F_ISSET(bhp, BH_WRITE))
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memcpy(&lsn, bhp->buf + mfp->lsn_off, sizeof(DB_LSN));
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/* Ensure the appropriate log records are on disk. */
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if (lg_info != NULL && (ret = log_flush(lg_info, &lsn)) != 0)
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goto err;
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/*
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* Call any pgout function. We set the callpgin flag so that we flag
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* that the contents of the buffer will need to be passed through pgin
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* before they are reused.
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*/
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if (mfp->ftype == 0)
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ret = 0;
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else {
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callpgin = 1;
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if ((ret = __memp_pg(dbmfp, bhp, 0)) != 0)
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goto err;
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}
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/* Temporary files may not yet have been created. */
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LOCKHANDLE(dbmp, dbmfp->mutexp);
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if (dbmfp->fd == -1)
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if ((ret = __db_appname(dbenv, DB_APP_TMP,
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NULL, NULL, &dbmfp->fd, NULL)) != 0 || dbmfp->fd == -1) {
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UNLOCKHANDLE(dbmp, dbmfp->mutexp);
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__db_err(dbenv,
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"unable to create temporary backing file");
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goto err;
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}
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/* Write the page out. */
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if ((ret = __db_seek(dbmfp->fd, pagesize, bhp->pgno, 0, SEEK_SET)) != 0)
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fail = "seek";
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else if ((ret = __db_write(dbmfp->fd, bhp->buf, pagesize, &nw)) != 0)
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fail = "write";
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UNLOCKHANDLE(dbmp, dbmfp->mutexp);
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if (ret != 0) {
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/*
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* XXX
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* Shut the compiler up; it doesn't understand the correlation
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* between the failing clauses to __db_lseek and __db_write and
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* this ret != 0.
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*/
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COMPQUIET(fail, NULL);
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goto syserr;
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}
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if (nw != (ssize_t)pagesize) {
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ret = EIO;
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fail = "write";
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goto syserr;
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}
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if (wrotep != NULL)
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*wrotep = 1;
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/* Unlock the buffer and reacquire the region lock. */
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UNLOCKBUFFER(dbmp, bhp);
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LOCKREGION(dbmp);
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/*
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* Clean up the flags based on a successful write.
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*
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* If we rewrote the page, it will need processing by the pgin
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* routine before reuse.
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*/
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if (callpgin)
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F_SET(bhp, BH_CALLPGIN);
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F_CLR(bhp, BH_DIRTY | BH_LOCKED);
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/*
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* If we write a buffer for which a checkpoint is waiting, update
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* the count of pending buffers (both in the mpool as a whole and
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* for this file). If the count for this file goes to zero, flush
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* the writes.
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*
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* XXX:
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* Don't lock the region around the sync, fsync(2) has no atomicity
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* issues.
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*
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* XXX:
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* We ignore errors from the sync -- it makes no sense to return an
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* error to the calling process, so set a flag causing the checkpoint
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* to be retried later.
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*/
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if (F_ISSET(bhp, BH_WRITE)) {
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if (mfp->lsn_cnt == 1) {
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UNLOCKREGION(dbmp);
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syncfail = __db_fsync(dbmfp->fd) != 0;
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LOCKREGION(dbmp);
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if (syncfail)
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F_SET(mp, MP_LSN_RETRY);
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}
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F_CLR(bhp, BH_WRITE);
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/*
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* If the buffer just written has a larger LSN than the current
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* max LSN written for this checkpoint, update the saved value.
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*/
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if (log_compare(&lsn, &mp->lsn) > 0)
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mp->lsn = lsn;
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--mp->lsn_cnt;
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--mfp->lsn_cnt;
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}
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/* Update the page clean/dirty statistics. */
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++mp->stat.st_page_clean;
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--mp->stat.st_page_dirty;
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/* Update I/O statistics. */
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++mp->stat.st_page_out;
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++mfp->stat.st_page_out;
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return (0);
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syserr: __db_err(dbenv, "%s: %s failed for page %lu",
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__memp_fn(dbmfp), fail, (u_long)bhp->pgno);
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err: /* Unlock the buffer and reacquire the region lock. */
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UNLOCKBUFFER(dbmp, bhp);
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LOCKREGION(dbmp);
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/*
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* Clean up the flags based on a failure.
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*
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* The page remains dirty but we remove our lock. If we rewrote the
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* page, it will need processing by the pgin routine before reuse.
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*/
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if (callpgin)
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F_SET(bhp, BH_CALLPGIN);
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F_CLR(bhp, BH_LOCKED);
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return (ret);
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}
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|
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/*
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* __memp_pg --
|
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* Call the pgin/pgout routine.
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*
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* PUBLIC: int __memp_pg __P((DB_MPOOLFILE *, BH *, int));
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*/
|
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int
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__memp_pg(dbmfp, bhp, is_pgin)
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DB_MPOOLFILE *dbmfp;
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BH *bhp;
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int is_pgin;
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{
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DBT dbt, *dbtp;
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DB_MPOOL *dbmp;
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DB_MPREG *mpreg;
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MPOOLFILE *mfp;
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int ftype, ret;
|
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dbmp = dbmfp->dbmp;
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mfp = dbmfp->mfp;
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|
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LOCKHANDLE(dbmp, dbmp->mutexp);
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ftype = mfp->ftype;
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for (mpreg = LIST_FIRST(&dbmp->dbregq);
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mpreg != NULL; mpreg = LIST_NEXT(mpreg, q)) {
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if (ftype != mpreg->ftype)
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continue;
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if (mfp->pgcookie_len == 0)
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dbtp = NULL;
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else {
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dbt.size = mfp->pgcookie_len;
|
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dbt.data = R_ADDR(dbmp, mfp->pgcookie_off);
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dbtp = &dbt;
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}
|
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UNLOCKHANDLE(dbmp, dbmp->mutexp);
|
|
|
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if (is_pgin) {
|
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if (mpreg->pgin != NULL && (ret =
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mpreg->pgin(bhp->pgno, bhp->buf, dbtp)) != 0)
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goto err;
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} else
|
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if (mpreg->pgout != NULL && (ret =
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mpreg->pgout(bhp->pgno, bhp->buf, dbtp)) != 0)
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goto err;
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break;
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}
|
|
|
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if (mpreg == NULL)
|
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UNLOCKHANDLE(dbmp, dbmp->mutexp);
|
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|
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return (0);
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|
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err: UNLOCKHANDLE(dbmp, dbmp->mutexp);
|
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__db_err(dbmp->dbenv, "%s: %s failed for page %lu",
|
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__memp_fn(dbmfp), is_pgin ? "pgin" : "pgout", (u_long)bhp->pgno);
|
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return (ret);
|
|
}
|
|
|
|
/*
|
|
* __memp_bhfree --
|
|
* Free a bucket header and its referenced data.
|
|
*
|
|
* PUBLIC: void __memp_bhfree __P((DB_MPOOL *, MPOOLFILE *, BH *, int));
|
|
*/
|
|
void
|
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__memp_bhfree(dbmp, mfp, bhp, free_mem)
|
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DB_MPOOL *dbmp;
|
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MPOOLFILE *mfp;
|
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BH *bhp;
|
|
int free_mem;
|
|
{
|
|
size_t off;
|
|
|
|
/* Delete the buffer header from the hash bucket queue. */
|
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off = BUCKET(dbmp->mp, R_OFFSET(dbmp, mfp), bhp->pgno);
|
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SH_TAILQ_REMOVE(&dbmp->htab[off], bhp, hq, __bh);
|
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|
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/* Delete the buffer header from the LRU queue. */
|
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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;
|
|
}
|
|
}
|
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|
|
/*
|
|
* __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), 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)__db_close(dbmfp->fd);
|
|
dbmfp->fd = fd;
|
|
F_SET(dbmfp, MP_UPGRADE);
|
|
ret = 0;
|
|
}
|
|
FREES(rpath);
|
|
return (ret);
|
|
}
|