mp_fopen.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*-
* 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_fopen.c 10.60 (Sleepycat) 1/1/99";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#endif
#include "db_int.h"
#include "shqueue.h"
#include "db_shash.h"
#include "mp.h"
#include "common_ext.h"
static int __memp_mf_close __P((DB_MPOOL *, DB_MPOOLFILE *));
static int __memp_mf_open __P((DB_MPOOL *,
const char *, size_t, db_pgno_t, DB_MPOOL_FINFO *, MPOOLFILE **));
/*
* memp_fopen --
* Open a backing file for the memory pool.
*/
int
memp_fopen(dbmp, path, flags, mode, pagesize, finfop, retp)
DB_MPOOL *dbmp;
const char *path;
u_int32_t flags;
int mode;
size_t pagesize;
DB_MPOOL_FINFO *finfop;
DB_MPOOLFILE **retp;
{
int ret;
MP_PANIC_CHECK(dbmp);
/* Validate arguments. */
if ((ret = __db_fchk(dbmp->dbenv,
"memp_fopen", flags, DB_CREATE | DB_NOMMAP | DB_RDONLY)) != 0)
return (ret);
/* Require a non-zero pagesize. */
if (pagesize == 0) {
__db_err(dbmp->dbenv, "memp_fopen: pagesize not specified");
return (EINVAL);
}
if (finfop != NULL && finfop->clear_len > pagesize)
return (EINVAL);
return (__memp_fopen(dbmp,
NULL, path, flags, mode, pagesize, 1, finfop, retp));
}
/*
* __memp_fopen --
* Open a backing file for the memory pool; internal version.
*
* PUBLIC: int __memp_fopen __P((DB_MPOOL *, MPOOLFILE *, const char *,
* PUBLIC: u_int32_t, int, size_t, int, DB_MPOOL_FINFO *, DB_MPOOLFILE **));
*/
int
__memp_fopen(dbmp, mfp, path, flags, mode, pagesize, needlock, finfop, retp)
DB_MPOOL *dbmp;
MPOOLFILE *mfp;
const char *path;
u_int32_t flags;
int mode, needlock;
size_t pagesize;
DB_MPOOL_FINFO *finfop;
DB_MPOOLFILE **retp;
{
DB_ENV *dbenv;
DB_MPOOLFILE *dbmfp;
DB_MPOOL_FINFO finfo;
db_pgno_t last_pgno;
size_t maxmap;
u_int32_t mbytes, bytes;
int ret;
u_int8_t idbuf[DB_FILE_ID_LEN];
char *rpath;
dbenv = dbmp->dbenv;
ret = 0;
rpath = NULL;
/*
* If mfp is provided, we take the DB_MPOOL_FINFO information from
* the mfp. We don't bother initializing everything, because some
* of them are expensive to acquire. If no mfp is provided and the
* finfop argument is NULL, we default the values.
*/
if (finfop == NULL) {
memset(&finfo, 0, sizeof(finfo));
if (mfp != NULL) {
finfo.ftype = mfp->ftype;
finfo.pgcookie = NULL;
finfo.fileid = NULL;
finfo.lsn_offset = mfp->lsn_off;
finfo.clear_len = mfp->clear_len;
} else {
finfo.ftype = 0;
finfo.pgcookie = NULL;
finfo.fileid = NULL;
finfo.lsn_offset = -1;
finfo.clear_len = 0;
}
finfop = &finfo;
}
/* Allocate and initialize the per-process structure. */
if ((ret = __os_calloc(1, sizeof(DB_MPOOLFILE), &dbmfp)) != 0)
return (ret);
dbmfp->dbmp = dbmp;
dbmfp->fd = -1;
dbmfp->ref = 1;
if (LF_ISSET(DB_RDONLY))
F_SET(dbmfp, MP_READONLY);
if (path == NULL) {
if (LF_ISSET(DB_RDONLY)) {
__db_err(dbenv,
"memp_fopen: temporary files can't be readonly");
ret = EINVAL;
goto err;
}
last_pgno = 0;
} else {
/* Get the real name for this file and open it. */
if ((ret = __db_appname(dbenv,
DB_APP_DATA, NULL, path, 0, NULL, &rpath)) != 0)
goto err;
if ((ret = __db_open(rpath,
LF_ISSET(DB_CREATE | DB_RDONLY),
DB_CREATE | DB_RDONLY, mode, &dbmfp->fd)) != 0) {
__db_err(dbenv, "%s: %s", rpath, strerror(ret));
goto err;
}
/*
* Don't permit files that aren't a multiple of the pagesize,
* and find the number of the last page in the file, all the
* time being careful not to overflow 32 bits.
*
* !!!
* We can't use off_t's here, or in any code in the mainline
* library for that matter. (We have to use them in the os
* stubs, of course, as there are system calls that take them
* as arguments.) The reason is that some customers build in
* environments where an off_t is 32-bits, but still run where
* offsets are 64-bits, and they pay us a lot of money.
*/
if ((ret = __os_ioinfo(rpath,
dbmfp->fd, &mbytes, &bytes, NULL)) != 0) {
__db_err(dbenv, "%s: %s", rpath, strerror(ret));
goto err;
}
/* Page sizes have to be a power-of-two, ignore mbytes. */
if (bytes % pagesize != 0) {
__db_err(dbenv,
"%s: file size not a multiple of the pagesize",
rpath);
ret = EINVAL;
goto err;
}
last_pgno = mbytes * (MEGABYTE / pagesize);
last_pgno += bytes / pagesize;
/* Correction: page numbers are zero-based, not 1-based. */
if (last_pgno != 0)
--last_pgno;
/*
* Get the file id if we weren't given one. Generated file id's
* don't use timestamps, otherwise there'd be no chance of any
* other process joining the party.
*/
if (finfop->fileid == NULL) {
if ((ret = __os_fileid(dbenv, rpath, 0, idbuf)) != 0)
goto err;
finfop->fileid = idbuf;
}
}
/*
* If we weren't provided an underlying shared object to join with,
* find/allocate the shared file objects. Also allocate space for
* for the per-process thread lock.
*/
if (needlock)
LOCKREGION(dbmp);
if (mfp == NULL)
ret = __memp_mf_open(dbmp,
path, pagesize, last_pgno, finfop, &mfp);
else {
++mfp->ref;
ret = 0;
}
if (ret == 0 &&
F_ISSET(dbmp, MP_LOCKHANDLE) && (ret =
__memp_alloc(dbmp, sizeof(db_mutex_t), NULL, &dbmfp->mutexp)) == 0)
LOCKINIT(dbmp, dbmfp->mutexp);
if (needlock)
UNLOCKREGION(dbmp);
if (ret != 0)
goto err;
dbmfp->mfp = mfp;
/*
* If a file:
* + is read-only
* + isn't temporary
* + doesn't require any pgin/pgout support
* + the DB_NOMMAP flag wasn't set
* + and is less than mp_mmapsize bytes in size
*
* we can mmap it instead of reading/writing buffers. Don't do error
* checking based on the mmap call failure. We want to do normal I/O
* on the file if the reason we failed was because the file was on an
* NFS mounted partition, and we can fail in buffer I/O just as easily
* as here.
*
* XXX
* We'd like to test to see if the file is too big to mmap. Since we
* don't know what size or type off_t's or size_t's are, or the largest
* unsigned integral type is, or what random insanity the local C
* compiler will perpetrate, doing the comparison in a portable way is
* flatly impossible. Hope that mmap fails if the file is too large.
*/
#define DB_MAXMMAPSIZE (10 * 1024 * 1024) /* 10 Mb. */
if (F_ISSET(mfp, MP_CAN_MMAP)) {
if (!F_ISSET(dbmfp, MP_READONLY))
F_CLR(mfp, MP_CAN_MMAP);
if (path == NULL)
F_CLR(mfp, MP_CAN_MMAP);
if (finfop->ftype != 0)
F_CLR(mfp, MP_CAN_MMAP);
if (LF_ISSET(DB_NOMMAP))
F_CLR(mfp, MP_CAN_MMAP);
maxmap = dbenv == NULL || dbenv->mp_mmapsize == 0 ?
DB_MAXMMAPSIZE : dbenv->mp_mmapsize;
if (mbytes > maxmap / MEGABYTE ||
(mbytes == maxmap / MEGABYTE && bytes >= maxmap % MEGABYTE))
F_CLR(mfp, MP_CAN_MMAP);
}
dbmfp->addr = NULL;
if (F_ISSET(mfp, MP_CAN_MMAP)) {
dbmfp->len = (size_t)mbytes * MEGABYTE + bytes;
if (__db_mapfile(rpath,
dbmfp->fd, dbmfp->len, 1, &dbmfp->addr) != 0) {
dbmfp->addr = NULL;
F_CLR(mfp, MP_CAN_MMAP);
}
}
if (rpath != NULL)
__os_freestr(rpath);
LOCKHANDLE(dbmp, dbmp->mutexp);
TAILQ_INSERT_TAIL(&dbmp->dbmfq, dbmfp, q);
UNLOCKHANDLE(dbmp, dbmp->mutexp);
*retp = dbmfp;
return (0);
err: /*
* Note that we do not have to free the thread mutex, because we
* never get to here after we have successfully allocated it.
*/
if (rpath != NULL)
__os_freestr(rpath);
if (dbmfp->fd != -1)
(void)__os_close(dbmfp->fd);
if (dbmfp != NULL)
__os_free(dbmfp, sizeof(DB_MPOOLFILE));
return (ret);
}
/*
* __memp_mf_open --
* Open an MPOOLFILE.
*/
static int
__memp_mf_open(dbmp, path, pagesize, last_pgno, finfop, retp)
DB_MPOOL *dbmp;
const char *path;
size_t pagesize;
db_pgno_t last_pgno;
DB_MPOOL_FINFO *finfop;
MPOOLFILE **retp;
{
MPOOLFILE *mfp;
int ret;
void *p;
#define ISTEMPORARY (path == NULL)
/*
* Walk the list of MPOOLFILE's, looking for a matching file.
* Temporary files can't match previous files.
*/
if (!ISTEMPORARY)
for (mfp = SH_TAILQ_FIRST(&dbmp->mp->mpfq, __mpoolfile);
mfp != NULL; mfp = SH_TAILQ_NEXT(mfp, q, __mpoolfile)) {
if (F_ISSET(mfp, MP_TEMP))
continue;
if (!memcmp(finfop->fileid,
R_ADDR(dbmp, mfp->fileid_off), DB_FILE_ID_LEN)) {
if (finfop->clear_len != mfp->clear_len ||
finfop->ftype != mfp->ftype ||
pagesize != mfp->stat.st_pagesize) {
__db_err(dbmp->dbenv,
"%s: ftype, clear length or pagesize changed",
path);
return (EINVAL);
}
/* Found it: increment the reference count. */
++mfp->ref;
*retp = mfp;
return (0);
}
}
/* Allocate a new MPOOLFILE. */
if ((ret = __memp_alloc(dbmp, sizeof(MPOOLFILE), NULL, &mfp)) != 0)
return (ret);
*retp = mfp;
/* Initialize the structure. */
memset(mfp, 0, sizeof(MPOOLFILE));
mfp->ref = 1;
mfp->ftype = finfop->ftype;
mfp->lsn_off = finfop->lsn_offset;
mfp->clear_len = finfop->clear_len;
/*
* If the user specifies DB_MPOOL_LAST or DB_MPOOL_NEW on a memp_fget,
* we have to know the last page in the file. Figure it out and save
* it away.
*/
mfp->stat.st_pagesize = pagesize;
mfp->orig_last_pgno = mfp->last_pgno = last_pgno;
if (ISTEMPORARY)
F_SET(mfp, MP_TEMP);
else {
/* Copy the file path into shared memory. */
if ((ret = __memp_alloc(dbmp,
strlen(path) + 1, &mfp->path_off, &p)) != 0)
goto err;
memcpy(p, path, strlen(path) + 1);
/* Copy the file identification string into shared memory. */
if ((ret = __memp_alloc(dbmp,
DB_FILE_ID_LEN, &mfp->fileid_off, &p)) != 0)
goto err;
memcpy(p, finfop->fileid, DB_FILE_ID_LEN);
F_SET(mfp, MP_CAN_MMAP);
}
/* Copy the page cookie into shared memory. */
if (finfop->pgcookie == NULL || finfop->pgcookie->size == 0) {
mfp->pgcookie_len = 0;
mfp->pgcookie_off = 0;
} else {
if ((ret = __memp_alloc(dbmp,
finfop->pgcookie->size, &mfp->pgcookie_off, &p)) != 0)
goto err;
memcpy(p, finfop->pgcookie->data, finfop->pgcookie->size);
mfp->pgcookie_len = finfop->pgcookie->size;
}
/* Prepend the MPOOLFILE to the list of MPOOLFILE's. */
SH_TAILQ_INSERT_HEAD(&dbmp->mp->mpfq, mfp, q, __mpoolfile);
if (0) {
err: if (mfp->path_off != 0)
__db_shalloc_free(dbmp->addr,
R_ADDR(dbmp, mfp->path_off));
if (mfp->fileid_off != 0)
__db_shalloc_free(dbmp->addr,
R_ADDR(dbmp, mfp->fileid_off));
if (mfp != NULL)
__db_shalloc_free(dbmp->addr, mfp);
mfp = NULL;
}
return (0);
}
/*
* memp_fclose --
* Close a backing file for the memory pool.
*/
int
memp_fclose(dbmfp)
DB_MPOOLFILE *dbmfp;
{
DB_MPOOL *dbmp;
int ret, t_ret;
dbmp = dbmfp->dbmp;
ret = 0;
MP_PANIC_CHECK(dbmp);
for (;;) {
LOCKHANDLE(dbmp, dbmp->mutexp);
/*
* We have to reference count DB_MPOOLFILE structures as other
* threads may be using them. The problem only happens if the
* application makes a bad design choice. Here's the path:
*
* Thread A opens a database.
* Thread B uses thread A's DB_MPOOLFILE to write a buffer
* in order to free up memory in the mpool cache.
* Thread A closes the database while thread B is using the
* DB_MPOOLFILE structure.
*
* By opening all databases before creating the threads, and
* closing them after the threads have exited, applications
* get better performance and avoid the problem path entirely.
*
* Regardless, holding the DB_MPOOLFILE to flush a dirty buffer
* is a short-term lock, even in worst case, since we better be
* the only thread of control using the DB_MPOOLFILE structure
* to read pages *into* the cache. Wait until we're the only
* reference holder and remove the DB_MPOOLFILE structure from
* the list, so nobody else can even find it.
*/
if (dbmfp->ref == 1) {
TAILQ_REMOVE(&dbmp->dbmfq, dbmfp, q);
break;
}
UNLOCKHANDLE(dbmp, dbmp->mutexp);
(void)__os_sleep(1, 0);
}
UNLOCKHANDLE(dbmp, dbmp->mutexp);
/* Complain if pinned blocks never returned. */
if (dbmfp->pinref != 0)
__db_err(dbmp->dbenv, "%s: close: %lu blocks left pinned",
__memp_fn(dbmfp), (u_long)dbmfp->pinref);
/* Close the underlying MPOOLFILE. */
(void)__memp_mf_close(dbmp, dbmfp);
/* Discard any mmap information. */
if (dbmfp->addr != NULL &&
(ret = __db_unmapfile(dbmfp->addr, dbmfp->len)) != 0)
__db_err(dbmp->dbenv,
"%s: %s", __memp_fn(dbmfp), strerror(ret));
/* Close the file; temporary files may not yet have been created. */
if (dbmfp->fd != -1 && (t_ret = __os_close(dbmfp->fd)) != 0) {
__db_err(dbmp->dbenv,
"%s: %s", __memp_fn(dbmfp), strerror(t_ret));
if (ret != 0)
t_ret = ret;
}
/* Free memory. */
if (dbmfp->mutexp != NULL) {
LOCKREGION(dbmp);
__db_shalloc_free(dbmp->addr, dbmfp->mutexp);
UNLOCKREGION(dbmp);
}
/* Discard the DB_MPOOLFILE structure. */
__os_free(dbmfp, sizeof(DB_MPOOLFILE));
return (ret);
}
/*
* __memp_mf_close --
* Close down an MPOOLFILE.
*/
static int
__memp_mf_close(dbmp, dbmfp)
DB_MPOOL *dbmp;
DB_MPOOLFILE *dbmfp;
{
BH *bhp, *nbhp;
MPOOL *mp;
MPOOLFILE *mfp;
size_t mf_offset;
mp = dbmp->mp;
mfp = dbmfp->mfp;
LOCKREGION(dbmp);
/* If more than a single reference, simply decrement. */
if (mfp->ref > 1) {
--mfp->ref;
goto ret1;
}
/*
* Move any BH's held by the file to the free list. We don't free the
* memory itself because we may be discarding the memory pool, and it's
* fairly expensive to reintegrate the buffers back into the region for
* no purpose.
*/
mf_offset = R_OFFSET(dbmp, mfp);
for (bhp = SH_TAILQ_FIRST(&mp->bhq, __bh); bhp != NULL; bhp = nbhp) {
nbhp = SH_TAILQ_NEXT(bhp, q, __bh);
#ifdef DEBUG_NO_DIRTY
/* Complain if we find any blocks that were left dirty. */
if (F_ISSET(bhp, BH_DIRTY))
__db_err(dbmp->dbenv,
"%s: close: pgno %lu left dirty; ref %lu",
__memp_fn(dbmfp),
(u_long)bhp->pgno, (u_long)bhp->ref);
#endif
if (bhp->mf_offset == mf_offset) {
if (F_ISSET(bhp, BH_DIRTY)) {
++mp->stat.st_page_clean;
--mp->stat.st_page_dirty;
}
__memp_bhfree(dbmp, mfp, bhp, 0);
SH_TAILQ_INSERT_HEAD(&mp->bhfq, bhp, q, __bh);
}
}
/* Delete from the list of MPOOLFILEs. */
SH_TAILQ_REMOVE(&mp->mpfq, mfp, q, __mpoolfile);
/* Free the space. */
if (mfp->path_off != 0)
__db_shalloc_free(dbmp->addr, R_ADDR(dbmp, mfp->path_off));
if (mfp->fileid_off != 0)
__db_shalloc_free(dbmp->addr, R_ADDR(dbmp, mfp->fileid_off));
if (mfp->pgcookie_off != 0)
__db_shalloc_free(dbmp->addr, R_ADDR(dbmp, mfp->pgcookie_off));
__db_shalloc_free(dbmp->addr, mfp);
ret1: UNLOCKREGION(dbmp);
return (0);
}