diff options
Diffstat (limited to 'db2/common/db_region.c')
| -rw-r--r-- | db2/common/db_region.c | 873 |
1 files changed, 0 insertions, 873 deletions
diff --git a/db2/common/db_region.c b/db2/common/db_region.c deleted file mode 100644 index 12abfa5..0000000 --- a/db2/common/db_region.c +++ /dev/null @@ -1,873 +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[] = "@(#)db_region.c 10.53 (Sleepycat) 11/10/98"; -#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 "common_ext.h" - -static int __db_growregion __P((REGINFO *, size_t)); - -/* - * __db_rattach -- - * Optionally create and attach to a shared memory region. - * - * PUBLIC: int __db_rattach __P((REGINFO *)); - */ -int -__db_rattach(infop) - REGINFO *infop; -{ - RLAYOUT *rlp, rl; - size_t grow_region, size; - ssize_t nr, nw; - u_int32_t flags, mbytes, bytes; - u_int8_t *p; - int malloc_possible, ret, retry_cnt; - - grow_region = 0; - malloc_possible = 1; - ret = retry_cnt = 0; - - /* Round off the requested size to the next page boundary. */ - DB_ROUNDOFF(infop->size, DB_VMPAGESIZE); - - /* Some architectures have hard limits on the maximum region size. */ -#ifdef DB_REGIONSIZE_MAX - if (infop->size > DB_REGIONSIZE_MAX) { - __db_err(infop->dbenv, "__db_rattach: cache size too large"); - return (EINVAL); - } -#endif - - /* Intialize the return information in the REGINFO structure. */ -loop: infop->addr = NULL; - infop->fd = -1; - infop->segid = INVALID_SEGID; - if (infop->name != NULL) { - __os_freestr(infop->name); - infop->name = NULL; - } - F_CLR(infop, REGION_CANGROW | REGION_CREATED); - -#ifndef HAVE_SPINLOCKS - /* - * XXX - * Lacking spinlocks, we must have a file descriptor for fcntl(2) - * locking, which implies using mmap(2) to map in a regular file. - * (Theoretically, we could probably get a file descriptor to lock - * other types of shared regions, but I don't see any reason to - * bother.) - * - * Since we may be using shared memory regions, e.g., shmget(2), - * and not mmap of regular files, the backing file may be only a - * few tens of bytes in length. So, this depends on the ability - * to fcntl lock file offsets much larger than the physical file. - */ - malloc_possible = 0; -#endif - -#ifdef __hppa - /* - * XXX - * HP-UX won't permit mutexes to live in anything but shared memory. - * Instantiate a shared region file on that architecture, regardless. - */ - malloc_possible = 0; -#endif - /* - * If a region is truly private, malloc the memory. That's faster - * than either anonymous memory or a shared file. - */ - if (malloc_possible && F_ISSET(infop, REGION_PRIVATE)) { - if ((ret = __os_malloc(infop->size, NULL, &infop->addr)) != 0) - return (ret); - - /* - * It's sometimes significantly faster to page-fault in all of - * the region's pages before we run the application, as we see - * nasty side-effects when we page-fault while holding various - * locks, i.e., the lock takes a long time to acquire because - * of the underlying page fault, and the other threads convoy - * behind the lock holder. - */ - if (DB_GLOBAL(db_region_init)) - for (p = infop->addr; - p < (u_int8_t *)infop->addr + infop->size; - p += DB_VMPAGESIZE) - p[0] = '\0'; - - F_SET(infop, REGION_CREATED | REGION_MALLOC); - goto region_init; - } - - /* - * Get the name of the region (creating the file if a temporary file - * is being used). The dbenv contains the current DB environment, - * including naming information. The path argument may be a file or - * a directory. If path is a directory, it must exist and file is the - * file name to be created inside the directory. If path is a file, - * then file must be NULL. - */ - if ((ret = __db_appname(infop->dbenv, infop->appname, infop->path, - infop->file, infop->dbflags, &infop->fd, &infop->name)) != 0) - return (ret); - if (infop->fd != -1) - F_SET(infop, REGION_CREATED); - - /* - * Try to create the file, if we have authority. We have to make sure - * that multiple threads/processes attempting to simultaneously create - * the region are properly ordered, so we open it using DB_CREATE and - * DB_EXCL, so two attempts to create the region will return failure in - * one. - */ - if (infop->fd == -1 && infop->dbflags & DB_CREATE) { - flags = infop->dbflags; - LF_SET(DB_EXCL); - if ((ret = __db_open(infop->name, - flags, flags, infop->mode, &infop->fd)) == 0) - F_SET(infop, REGION_CREATED); - else - if (ret != EEXIST) - goto errmsg; - } - - /* If we couldn't create the file, try and open it. */ - if (infop->fd == -1) { - flags = infop->dbflags; - LF_CLR(DB_CREATE | DB_EXCL); - if ((ret = __db_open(infop->name, - flags, flags, infop->mode, &infop->fd)) != 0) - goto errmsg; - } - - /* - * There are three cases we support: - * 1. Named anonymous memory (shmget(2)). - * 2. Unnamed anonymous memory (mmap(2): MAP_ANON/MAP_ANONYMOUS). - * 3. Memory backed by a regular file (mmap(2)). - * - * We instantiate a backing file in all cases, which contains at least - * the RLAYOUT structure, and in case #3, contains the actual region. - * This is necessary for a couple of reasons: - * - * First, the mpool region uses temporary files to name regions, and - * since you may have multiple regions in the same directory, we need - * a filesystem name to ensure that they don't collide. - * - * Second, applications are allowed to forcibly remove regions, even - * if they don't know anything about them other than the name. If a - * region is backed by anonymous memory, there has to be some way for - * the application to find out that information, and, in some cases, - * determine ID information for the anonymous memory. - */ - if (F_ISSET(infop, REGION_CREATED)) { - /* - * If we're using anonymous memory to back this region, set - * the flag. - */ - if (DB_GLOBAL(db_region_anon)) - F_SET(infop, REGION_ANONYMOUS); - - /* - * If we're using a regular file to back a region we created, - * grow it to the specified size. - */ - if (!DB_GLOBAL(db_region_anon) && - (ret = __db_growregion(infop, infop->size)) != 0) - goto err; - } else { - /* - * If we're joining a region, figure out what it looks like. - * - * XXX - * We have to figure out if the file is a regular file backing - * a region that we want to map into our address space, or a - * file with the information we need to find a shared anonymous - * region that we want to map into our address space. - * - * All this noise is because some systems don't have a coherent - * VM and buffer cache, and worse, if you mix operations on the - * VM and buffer cache, half the time you hang the system. - * - * There are two possibilities. If the file is the size of an - * RLAYOUT structure, then we know that the real region is in - * shared memory, because otherwise it would be bigger. (As - * the RLAYOUT structure size is smaller than a disk sector, - * the only way it can be this size is if deliberately written - * that way.) In which case, retrieve the information we need - * from the RLAYOUT structure and use it to acquire the shared - * memory. - * - * If the structure is larger than an RLAYOUT structure, then - * the file is backing the shared memory region, and we use - * the current size of the file without reading any information - * from the file itself so that we don't confuse the VM. - * - * And yes, this makes me want to take somebody and kill them, - * but I can't think of any other solution. - */ - if ((ret = __os_ioinfo(infop->name, - infop->fd, &mbytes, &bytes, NULL)) != 0) - goto errmsg; - size = mbytes * MEGABYTE + bytes; - - if (size <= sizeof(RLAYOUT)) { - /* - * If the size is too small, the read fails or the - * valid flag is incorrect, assume it's because the - * RLAYOUT information hasn't been written out yet, - * and retry. - */ - if (size < sizeof(RLAYOUT)) - goto retry; - if ((ret = - __os_read(infop->fd, &rl, sizeof(rl), &nr)) != 0) - goto retry; - if (rl.valid != DB_REGIONMAGIC) - goto retry; - - /* Copy the size, memory id and characteristics. */ - size = rl.size; - infop->segid = rl.segid; - if (F_ISSET(&rl, REGION_ANONYMOUS)) - F_SET(infop, REGION_ANONYMOUS); - } - - /* - * If the region is larger than we think, that's okay, use the - * current size. If it's smaller than we think, and we were - * just using the default size, that's okay, use the current - * size. If it's smaller than we think and we really care, - * save the size and we'll catch that further down -- we can't - * correct it here because we have to have a lock to grow the - * region. - */ - if (infop->size > size && !F_ISSET(infop, REGION_SIZEDEF)) - grow_region = infop->size; - infop->size = size; - } - - /* - * Map the region into our address space. If we're creating it, the - * underlying routines will make it the right size. - * - * There are at least two cases where we can "reasonably" fail when - * we attempt to map in the region. On Windows/95, closing the last - * reference to a region causes it to be zeroed out. On UNIX, when - * using the shmget(2) interfaces, the region will no longer exist - * if the system was rebooted. In these cases, the underlying map call - * returns EAGAIN, and we *remove* our file and try again. There are - * obvious races in doing this, but it should eventually settle down - * to a winner and then things should proceed normally. - */ - if ((ret = __db_mapregion(infop->name, infop)) != 0) { - if (ret == EAGAIN) { - /* - * Pretend we created the region even if we didn't so - * that our error processing unlinks it. - */ - F_SET(infop, REGION_CREATED); - ret = 0; - goto retry; - } else - goto err; - } - -region_init: - /* - * Initialize the common region information. - * - * !!! - * We have to order the region creates so that two processes don't try - * to simultaneously create the region. This is handled by using the - * DB_CREATE and DB_EXCL flags when we create the "backing" region file. - * - * We also have to order region joins so that processes joining regions - * never see inconsistent data. We'd like to play permissions games - * with the backing file, but we can't because WNT filesystems won't - * open a file mode 0. - */ - rlp = (RLAYOUT *)infop->addr; - if (F_ISSET(infop, REGION_CREATED)) { - /* - * The process creating the region acquires a lock before it - * sets the valid flag. Any processes joining the region will - * check the valid flag before acquiring the lock. - * - * Check the return of __db_mutex_init() and __db_mutex_lock(), - * even though we don't usually check elsewhere. This is the - * first lock we initialize and acquire, and we have to know if - * it fails. (It CAN fail, e.g., SunOS, when using fcntl(2) - * for locking, with an in-memory filesystem specified as the - * database home.) - */ - if ((ret = __db_mutex_init(&rlp->lock, - MUTEX_LOCK_OFFSET(rlp, &rlp->lock))) != 0 || - (ret = __db_mutex_lock(&rlp->lock, infop->fd)) != 0) - goto err; - - /* Initialize the remaining region information. */ - rlp->refcnt = 1; - rlp->size = infop->size; - db_version(&rlp->majver, &rlp->minver, &rlp->patch); - rlp->panic = 0; - rlp->segid = infop->segid; - rlp->flags = 0; - if (F_ISSET(infop, REGION_ANONYMOUS)) - F_SET(rlp, REGION_ANONYMOUS); - - /* - * Fill in the valid field last -- use a magic number, memory - * may not be zero-filled, and we want to minimize the chance - * for collision. - */ - rlp->valid = DB_REGIONMAGIC; - - /* - * If the region is anonymous, write the RLAYOUT information - * into the backing file so that future region join and unlink - * calls can find it. - * - * XXX - * We MUST do the seek before we do the write. On Win95, while - * closing the last reference to an anonymous shared region - * doesn't discard the region, it does zero it out. So, the - * REGION_CREATED may be set, but the file may have already - * been written and the file descriptor may be at the end of - * the file. - */ - if (F_ISSET(infop, REGION_ANONYMOUS)) { - if ((ret = __os_seek(infop->fd, 0, 0, 0, 0, 0)) != 0) - goto err; - if ((ret = - __os_write(infop->fd, rlp, sizeof(*rlp), &nw)) != 0) - goto err; - } - } else { - /* Check to see if the region has had catastrophic failure. */ - if (rlp->panic) { - ret = DB_RUNRECOVERY; - goto err; - } - - /* - * Check the valid flag to ensure the region is initialized. - * If the valid flag has not been set, the mutex may not have - * been initialized, and an attempt to get it could lead to - * random behavior. - */ - if (rlp->valid != DB_REGIONMAGIC) - goto retry; - - /* Get the region lock. */ - (void)__db_mutex_lock(&rlp->lock, infop->fd); - - /* - * We now own the region. There are a couple of things that - * may have gone wrong, however. - * - * Problem #1: while we were waiting for the lock, the region - * was deleted. Detected by re-checking the valid flag, since - * it's cleared by the delete region routines. - */ - if (rlp->valid != DB_REGIONMAGIC) { - (void)__db_mutex_unlock(&rlp->lock, infop->fd); - goto retry; - } - - /* - * Problem #3: when we checked the size of the file, it was - * still growing as part of creation. Detected by the fact - * that infop->size isn't the same size as the region. - */ - if (infop->size != rlp->size) { - (void)__db_mutex_unlock(&rlp->lock, infop->fd); - goto retry; - } - - /* Increment the reference count. */ - ++rlp->refcnt; - } - - /* Return the region in a locked condition. */ - - if (0) { -errmsg: __db_err(infop->dbenv, "%s: %s", infop->name, strerror(ret)); - -err: -retry: /* Discard the region. */ - if (infop->addr != NULL) { - (void)__db_unmapregion(infop); - infop->addr = NULL; - } - - /* Discard the backing file. */ - if (infop->fd != -1) { - (void)__os_close(infop->fd); - infop->fd = -1; - - if (F_ISSET(infop, REGION_CREATED)) - (void)__os_unlink(infop->name); - } - - /* Discard the name. */ - if (infop->name != NULL) { - __os_freestr(infop->name); - infop->name = NULL; - } - - /* - * If we had a temporary error, wait a few seconds and - * try again. - */ - if (ret == 0) { - if (++retry_cnt <= 3) { - __os_sleep(retry_cnt * 2, 0); - goto loop; - } - ret = EAGAIN; - } - } - - /* - * XXX - * HP-UX won't permit mutexes to live in anything but shared memory. - * Instantiate a shared region file on that architecture, regardless. - * - * XXX - * There's a problem in cleaning this up on application exit, or on - * application failure. If an application opens a database without - * an environment, we create a temporary backing mpool region for it. - * That region is marked REGION_PRIVATE, but as HP-UX won't permit - * mutexes to live in anything but shared memory, we instantiate a - * real file plus a memory region of some form. If the application - * crashes, the necessary information to delete the backing file and - * any system region (e.g., the shmget(2) segment ID) is no longer - * available. We can't completely fix the problem, but we try. - * - * The underlying UNIX __db_mapregion() code preferentially uses the - * mmap(2) interface with the MAP_ANON/MAP_ANONYMOUS flags for regions - * that are marked REGION_PRIVATE. This means that we normally aren't - * holding any system resources when we get here, in which case we can - * delete the backing file. This results in a short race, from the - * __db_open() call above to here. - * - * If, for some reason, we are holding system resources when we get - * here, we don't have any choice -- we can't delete the backing file - * because we may need it to detach from the resources. Set the - * REGION_LASTDETACH flag, so that we do all necessary cleanup when - * the application closes the region. - */ - if (F_ISSET(infop, REGION_PRIVATE) && !F_ISSET(infop, REGION_MALLOC)) { - if (F_ISSET(infop, REGION_HOLDINGSYS)) - F_SET(infop, REGION_LASTDETACH); - else { - F_SET(infop, REGION_REMOVED); - F_CLR(infop, REGION_CANGROW); - - (void)__os_close(infop->fd); - (void)__os_unlink(infop->name); - } - } - - return (ret); -} - -/* - * __db_rdetach -- - * De-attach from a shared memory region. - * - * PUBLIC: int __db_rdetach __P((REGINFO *)); - */ -int -__db_rdetach(infop) - REGINFO *infop; -{ - RLAYOUT *rlp; - int detach, ret, t_ret; - - ret = 0; - - /* - * If the region was removed when it was created, no further action - * is required. - */ - if (F_ISSET(infop, REGION_REMOVED)) - goto done; - /* - * If the region was created in memory returned by malloc, the only - * action required is freeing the memory. - */ - if (F_ISSET(infop, REGION_MALLOC)) { - __os_free(infop->addr, 0); - goto done; - } - - /* Otherwise, attach to the region and optionally delete it. */ - rlp = infop->addr; - - /* Get the lock. */ - (void)__db_mutex_lock(&rlp->lock, infop->fd); - - /* Decrement the reference count. */ - if (rlp->refcnt == 0) - __db_err(infop->dbenv, - "region rdetach: reference count went to zero!"); - else - --rlp->refcnt; - - /* - * If we're going to remove the region, clear the valid flag so - * that any region join that's blocked waiting for us will know - * what happened. - */ - detach = 0; - if (F_ISSET(infop, REGION_LASTDETACH)) { - if (rlp->refcnt == 0) { - detach = 1; - rlp->valid = 0; - } else - ret = EBUSY; - } - - /* Release the lock. */ - (void)__db_mutex_unlock(&rlp->lock, infop->fd); - - /* Close the backing file descriptor. */ - (void)__os_close(infop->fd); - infop->fd = -1; - - /* Discard our mapping of the region. */ - if ((t_ret = __db_unmapregion(infop)) != 0 && ret == 0) - ret = t_ret; - - /* Discard the region itself. */ - if (detach) { - if ((t_ret = - __db_unlinkregion(infop->name, infop) != 0) && ret == 0) - ret = t_ret; - if ((t_ret = __os_unlink(infop->name) != 0) && ret == 0) - ret = t_ret; - } - -done: /* Discard the name. */ - if (infop->name != NULL) { - __os_freestr(infop->name); - infop->name = NULL; - } - - return (ret); -} - -/* - * __db_runlink -- - * Remove a region. - * - * PUBLIC: int __db_runlink __P((REGINFO *, int)); - */ -int -__db_runlink(infop, force) - REGINFO *infop; - int force; -{ - RLAYOUT rl, *rlp; - size_t size; - ssize_t nr; - u_int32_t mbytes, bytes; - int fd, ret, t_ret; - char *name; - - /* - * XXX - * We assume that we've created a new REGINFO structure for this - * call, not used one that was already initialized. Regardless, - * if anyone is planning to use it after we're done, they're going - * to be sorely disappointed. - * - * If force isn't set, we attach to the region, set a flag to delete - * the region on last close, and let the region delete code do the - * work. - */ - if (!force) { - if ((ret = __db_rattach(infop)) != 0) - return (ret); - - rlp = (RLAYOUT *)infop->addr; - (void)__db_mutex_unlock(&rlp->lock, infop->fd); - - F_SET(infop, REGION_LASTDETACH); - - return (__db_rdetach(infop)); - } - - /* - * Otherwise, we don't want to attach to the region. We may have been - * called to clean up if a process died leaving a region locked and/or - * corrupted, which could cause the attach to hang. - */ - if ((ret = __db_appname(infop->dbenv, infop->appname, - infop->path, infop->file, infop->dbflags, NULL, &name)) != 0) - return (ret); - - /* - * An underlying file is created for all regions other than private - * (REGION_PRIVATE) ones, regardless of whether or not it's used to - * back the region. If that file doesn't exist, we're done. - */ - if (__os_exists(name, NULL) != 0) { - __os_freestr(name); - return (0); - } - - /* - * See the comments in __db_rattach -- figure out if this is a regular - * file backing a region or if it's a regular file with information - * about a region. - */ - if ((ret = __db_open(name, DB_RDONLY, DB_RDONLY, 0, &fd)) != 0) - goto errmsg; - if ((ret = __os_ioinfo(name, fd, &mbytes, &bytes, NULL)) != 0) - goto errmsg; - size = mbytes * MEGABYTE + bytes; - - if (size <= sizeof(RLAYOUT)) { - if ((ret = __os_read(fd, &rl, sizeof(rl), &nr)) != 0) - goto errmsg; - if (rl.valid != DB_REGIONMAGIC) { - __db_err(infop->dbenv, - "%s: illegal region magic number", name); - ret = EINVAL; - goto err; - } - - /* Set the size, memory id and characteristics. */ - infop->size = rl.size; - infop->segid = rl.segid; - if (F_ISSET(&rl, REGION_ANONYMOUS)) - F_SET(infop, REGION_ANONYMOUS); - } else { - infop->size = size; - infop->segid = INVALID_SEGID; - } - - /* Remove the underlying region. */ - ret = __db_unlinkregion(name, infop); - - /* - * Unlink the backing file. Close the open file descriptor first, - * because some architectures (e.g., Win32) won't unlink a file if - * open file descriptors remain. - */ - (void)__os_close(fd); - if ((t_ret = __os_unlink(name)) != 0 && ret == 0) - ret = t_ret; - - if (0) { -errmsg: __db_err(infop->dbenv, "%s: %s", name, strerror(ret)); -err: (void)__os_close(fd); - } - - __os_freestr(name); - return (ret); -} - -/* - * __db_rgrow -- - * Extend a region. - * - * PUBLIC: int __db_rgrow __P((REGINFO *, size_t)); - */ -int -__db_rgrow(infop, new_size) - REGINFO *infop; - size_t new_size; -{ - RLAYOUT *rlp; - size_t increment; - int ret; - - /* - * !!! - * This routine MUST be called with the region already locked. - */ - - /* The underlying routines have flagged if this region can grow. */ - if (!F_ISSET(infop, REGION_CANGROW)) - return (EINVAL); - - /* - * Round off the requested size to the next page boundary, and - * determine the additional space required. - */ - rlp = (RLAYOUT *)infop->addr; - DB_ROUNDOFF(new_size, DB_VMPAGESIZE); - increment = new_size - rlp->size; - - if ((ret = __db_growregion(infop, increment)) != 0) - return (ret); - - /* Update the on-disk region size. */ - rlp->size = new_size; - - /* Detach from and reattach to the region. */ - return (__db_rreattach(infop, new_size)); -} - -/* - * __db_growregion -- - * Grow a shared memory region. - */ -static int -__db_growregion(infop, increment) - REGINFO *infop; - size_t increment; -{ - db_pgno_t pages; - size_t i; - ssize_t nr, nw; - u_int32_t relative; - int ret; - char buf[DB_VMPAGESIZE]; - - /* Seek to the end of the region. */ - if ((ret = __os_seek(infop->fd, 0, 0, 0, 0, SEEK_END)) != 0) - goto err; - - /* Write nuls to the new bytes. */ - memset(buf, 0, sizeof(buf)); - - /* - * Some systems require that all of the bytes of the region be - * written before it can be mapped and accessed randomly, and - * other systems don't zero out the pages. - */ - if (__db_mapinit()) - /* Extend the region by writing each new page. */ - for (i = 0; i < increment; i += DB_VMPAGESIZE) { - if ((ret = - __os_write(infop->fd, buf, sizeof(buf), &nw)) != 0) - goto err; - if (nw != sizeof(buf)) - goto eio; - } - else { - /* - * Extend the region by writing the last page. If the region - * is >4Gb, increment may be larger than the maximum possible - * seek "relative" argument, as it's an unsigned 32-bit value. - * Break the offset into pages of 1MB each so that we don't - * overflow (2^20 + 2^32 is bigger than any memory I expect - * to see for awhile). - */ - pages = (increment - DB_VMPAGESIZE) / MEGABYTE; - relative = (increment - DB_VMPAGESIZE) % MEGABYTE; - if ((ret = __os_seek(infop->fd, - MEGABYTE, pages, relative, 0, SEEK_CUR)) != 0) - goto err; - if ((ret = __os_write(infop->fd, buf, sizeof(buf), &nw)) != 0) - goto err; - if (nw != sizeof(buf)) - goto eio; - - /* - * It's sometimes significantly faster to page-fault in all of - * the region's pages before we run the application, as we see - * nasty side-effects when we page-fault while holding various - * locks, i.e., the lock takes a long time to acquire because - * of the underlying page fault, and the other threads convoy - * behind the lock holder. - * - * We also use REGION_INIT to guarantee that there is enough - * disk space for the region, so we also write a byte to each - * page. Reading the byte is insufficient as some systems - * (e.g., Solaris) do not instantiate disk pages to satisfy - * a read, and so we don't know if there is enough disk space - * or not. - */ - if (DB_GLOBAL(db_region_init)) { - pages = increment / MEGABYTE; - relative = increment % MEGABYTE; - if ((ret = __os_seek(infop->fd, - MEGABYTE, pages, relative, 1, SEEK_END)) != 0) - goto err; - - /* Write a byte to each page. */ - for (i = 0; i < increment; i += DB_VMPAGESIZE) { - if ((ret = - __os_write(infop->fd, buf, 1, &nr)) != 0) - goto err; - if (nr != 1) - goto eio; - if ((ret = __os_seek(infop->fd, - 0, 0, DB_VMPAGESIZE - 1, 0, SEEK_CUR)) != 0) - goto err; - } - } - } - return (0); - -eio: ret = EIO; -err: __db_err(infop->dbenv, "region grow: %s", strerror(ret)); - return (ret); -} - -/* - * __db_rreattach -- - * Detach from and reattach to a region. - * - * PUBLIC: int __db_rreattach __P((REGINFO *, size_t)); - */ -int -__db_rreattach(infop, new_size) - REGINFO *infop; - size_t new_size; -{ - int ret; - -#ifdef DIAGNOSTIC - if (infop->name == NULL) { - __db_err(infop->dbenv, "__db_rreattach: name was NULL"); - return (EINVAL); - } -#endif - /* - * If we're growing an already mapped region, we have to unmap it - * and get it back. We have it locked, so nobody else can get in, - * which makes it fairly straight-forward to do, as everybody else - * is going to block while we do the unmap/remap. NB: if we fail - * to get it back, the pooch is genuinely screwed, because we can - * never release the lock we're holding. - * - * Detach from the region. We have to do this first so architectures - * that don't permit a file to be mapped into different places in the - * address space simultaneously, e.g., HP's PaRisc, will work. - */ - if ((ret = __db_unmapregion(infop)) != 0) - return (ret); - - /* Update the caller's REGINFO size to the new map size. */ - infop->size = new_size; - - /* Attach to the region. */ - ret = __db_mapregion(infop->name, infop); - - return (ret); -} |