C++ ReleaseReadLock函数代码示例

int
DFlushEntry(afs_int32 *fid)
{
    /* Flush pages modified by one entry. */
    struct buffer *tb;
    int code;

    ObtainReadLock(&afs_bufferLock);
    for (tb = phTable[pHash(fid)]; tb; tb = tb->hashNext)
	if (FidEq(tb->fid, fid) && tb->dirty) {
	    ObtainWriteLock(&tb->lock);
	    if (tb->dirty) {
		code = ReallyWrite(tb->fid, tb->page, tb->data);
		if (code) {
		    ReleaseWriteLock(&tb->lock);
		    ReleaseReadLock(&afs_bufferLock);
		    return code;
		}
		tb->dirty = 0;
	    }
	    ReleaseWriteLock(&tb->lock);
	}
    ReleaseReadLock(&afs_bufferLock);
    return 0;
}

int
DFlush(void)
{
    /* Flush all the modified buffers. */
    int i;
    struct buffer **tbp;
    afs_int32 code, rcode;

    rcode = 0;
    tbp = Buffers;
    ObtainReadLock(&afs_bufferLock);
    for (i = 0; i < nbuffers; i++, tbp++) {
	if ((*tbp)->dirty) {
	    ObtainWriteLock(&(*tbp)->lock);
	    (*tbp)->lockers++;
	    ReleaseReadLock(&afs_bufferLock);
	    if ((*tbp)->dirty) {
		code = ReallyWrite((*tbp)->fid, (*tbp)->page, (*tbp)->data);
		if (!code)
		    (*tbp)->dirty = 0;	/* Clear the dirty flag */
		if (code && !rcode) {
		    rcode = code;
		}
	    }
	    (*tbp)->lockers--;
	    ReleaseWriteLock(&(*tbp)->lock);
	    ObtainReadLock(&afs_bufferLock);
	}
    }
    ReleaseReadLock(&afs_bufferLock);
    return rcode;
}

/*!
 * \brief Query the AFSDB handler and wait for response.
 * \param  acellName
 * \return 0 for success. < 0 is error.
 */
static int
afs_GetCellHostsAFSDB(char *acellName)
{
    AFS_ASSERT_GLOCK();
    if (!afsdb_handler_running)
	return ENOENT;

    ObtainWriteLock(&afsdb_client_lock, 685);
    ObtainWriteLock(&afsdb_req_lock, 686);

    afsdb_req.cellname = acellName;

    afsdb_req.complete = 0;
    afsdb_req.pending = 1;
    afs_osi_Wakeup(&afsdb_req);
    ConvertWToRLock(&afsdb_req_lock);

    while (afsdb_handler_running && !afsdb_req.complete) {
	ReleaseReadLock(&afsdb_req_lock);
	afs_osi_Sleep(&afsdb_req);
	ObtainReadLock(&afsdb_req_lock);
    };

    ReleaseReadLock(&afsdb_req_lock);
    ReleaseWriteLock(&afsdb_client_lock);

    if (afsdb_req.cellname) {
	return 0;
    } else
	return ENOENT;
}

/*
 * this routine simulates a read in the Memory Cache
 */
int
afs_MemReadBlk(struct osi_file *fP, int offset, void *dest,
	       int size)
{
    struct memCacheEntry *mceP = (struct memCacheEntry *)fP;
    int bytesRead;

    ObtainReadLock(&mceP->afs_memLock);
    AFS_STATCNT(afs_MemReadBlk);
    if (offset < 0) {
	ReleaseReadLock(&mceP->afs_memLock);
	return 0;
    }
    /* use min of bytes in buffer or requested size */
    bytesRead = (size < mceP->size - offset) ? size : mceP->size - offset;

    if (bytesRead > 0) {
	AFS_GUNLOCK();
	memcpy(dest, mceP->data + offset, bytesRead);
	AFS_GLOCK();
    } else
	bytesRead = 0;

    ReleaseReadLock(&mceP->afs_memLock);
    return bytesRead;
}

/*
 * this routine simulates a readv in the Memory Cache
 */
int
afs_MemReadvBlk(struct memCacheEntry *mceP, int offset,
		struct iovec *iov, int nio, int size)
{
    int i;
    int bytesRead;
    int bytesToRead;

    ObtainReadLock(&mceP->afs_memLock);
    AFS_STATCNT(afs_MemReadBlk);
    if (offset < 0) {
	ReleaseReadLock(&mceP->afs_memLock);
	return 0;
    }
    /* use min of bytes in buffer or requested size */
    bytesRead = (size < mceP->size - offset) ? size : mceP->size - offset;

    if (bytesRead > 0) {
	for (i = 0, size = bytesRead; i < nio && size > 0; i++) {
	    bytesToRead = (size < iov[i].iov_len) ? size : iov[i].iov_len;
	    AFS_GUNLOCK();
	    memcpy(iov[i].iov_base, mceP->data + offset, bytesToRead);
	    AFS_GLOCK();
	    offset += bytesToRead;
	    size -= bytesToRead;
	}
	bytesRead -= size;
    } else
	bytesRead = 0;

    ReleaseReadLock(&mceP->afs_memLock);
    return bytesRead;
}

bool bbuf::empty(void)
{
    ObtainReadLock(&lock);
    if (count == 0) {
        ReleaseReadLock(&lock);
        return mtrue;
    } else {
        ReleaseReadLock(&lock);
        return mfalse;
    }
}

int
SRXAFSCB_GetServerPrefs(struct rx_call *a_call, afs_int32 a_index,
			afs_int32 * a_srvr_addr, afs_int32 * a_srvr_rank)
{
    int i, j;
    struct srvAddr *sa;

    RX_AFS_GLOCK();
    AFS_STATCNT(SRXAFSCB_GetServerPrefs);

    ObtainReadLock(&afs_xserver);

    /* Search the hash table for the server with this index */
    *a_srvr_addr = 0xffffffff;
    *a_srvr_rank = 0xffffffff;
    for (i = 0, j = 0; j < NSERVERS && i <= a_index; j++) {
	for (sa = afs_srvAddrs[j]; sa && i <= a_index; sa = sa->next_bkt, i++) {
	    if (i == a_index) {
		*a_srvr_addr = ntohl(sa->sa_ip);
		*a_srvr_rank = sa->sa_iprank;
	    }
	}
    }

    ReleaseReadLock(&afs_xserver);

    RX_AFS_GUNLOCK();

    return 0;
}

/*!
 * Find the first dcache of a file that has the specified fid.
 * Similar to afs_FindDCache, only that it takes a fid instead
 * of a vcache and it can get the first dcache.
 *
 * \param afid
 *
 * \return The found dcache or NULL.
 */
struct dcache *
afs_FindDCacheByFid(struct VenusFid *afid)
{
    afs_int32 i, index;
    struct dcache *tdc = NULL;

    i = DVHash(afid);
    ObtainWriteLock(&afs_xdcache, 758);
    for (index = afs_dvhashTbl[i]; index != NULLIDX;) {
	if (afs_indexUnique[index] == afid->Fid.Unique) {
	    tdc = afs_GetValidDSlot(index);
	    if (tdc) {
		ReleaseReadLock(&tdc->tlock);
		if (!FidCmp(&tdc->f.fid, afid)) {
		    break;		/* leaving refCount high for caller */
		}
		afs_PutDCache(tdc);
	    }
	}
	index = afs_dvnextTbl[index];
    }
    ReleaseWriteLock(&afs_xdcache);

    if (index == NULLIDX)
    	tdc = NULL;
    return tdc;
}

/*!
 * Print list of disconnected files.
 *
 * \note Call with afs_DDirtyVCListLock read locked.
 */
void
afs_DbgDisconFiles(void)
{
    struct vcache *tvc;
    struct afs_q *q;
    int i = 0;

    afs_warn("List of dirty files: \n");

    ObtainReadLock(&afs_disconDirtyLock);
    for (q = QPrev(&afs_disconDirty); q != &afs_disconDirty; q = QPrev(q)) {
        tvc = QEntry(q, struct vcache, dirtyq);

	afs_warn("Cell=%u Volume=%u VNode=%u Unique=%u\n",
		tvc->f.fid.Cell,
		tvc->f.fid.Fid.Volume,
		tvc->f.fid.Fid.Vnode,
		tvc->f.fid.Fid.Unique);

	i++;
	if (i >= 30)
	    osi_Panic("afs_DbgDisconFiles: loop in dirty list\n");
    }
    ReleaseReadLock(&afs_disconDirtyLock);
}

void
afs_GetDynrootMount(char **dynrootDir, int *dynrootLen,
		    struct AFSFetchStatus *status)
{
    ObtainReadLock(&afs_dynrootDirLock);
    if (!afs_dynrootMountDir) {
	ReleaseReadLock(&afs_dynrootDirLock);
	afs_RebuildDynrootMount();
	ObtainReadLock(&afs_dynrootDirLock);
    }

    if (dynrootDir)
	*dynrootDir = afs_dynrootMountDir;
    if (dynrootLen)
	*dynrootLen = afs_dynrootMountDirLen;

    if (status) {
	memset(status, 0, sizeof(struct AFSFetchStatus));
	status->FileType = Directory;
	status->LinkCount = 1;
	status->Length = afs_dynrootMountDirLen;
	status->DataVersion = 1;
	status->CallerAccess = PRSFS_LOOKUP | PRSFS_READ;
	status->AnonymousAccess = PRSFS_LOOKUP | PRSFS_READ;
	status->UnixModeBits = 0755;
	status->ParentVnode = 1;
	status->ParentUnique = 1;
	status->dataVersionHigh = 0;
    }
}

/*!
 * \brief Release the transaction lock.
 */
void
ulock_relLock(struct ubik_trans *atrans)
{
    if (atrans->locktype == LOCKWRITE && (atrans->flags & TRREADWRITE)) {
	ubik_print("Ubik: Internal Error: unlocking write lock with "
	           "TRREADWRITE?\n");
	abort();
    }

    if (atrans->flags & TRREADWRITE) {
	/* noop, TRREADWRITE means we don't actually lock anything */
    } else if (atrans->locktype == LOCKREAD) {
	ReleaseReadLock(&rwlock);
    } else if (atrans->locktype == LOCKWRITE) {
	ReleaseWriteLock(&rwlock);
    }

/*
 *ubik_print("Ubik: DEBUG: Thread 0x%x %s unlock\n", lwp_cpptr,
 *	     ((atrans->locktype == LOCKREAD) ? "READ" : "WRITE"));
 */

    atrans->locktype = 0;
    return;
}

//----------------------------------------------------------------------------------------
unsigned int GenericAccessGroupCollectionEntry::GetEntryCount() const
{
	ObtainReadLock();
	unsigned int entryCount = (unsigned int)entries.size();
	ReleaseReadLock();
	return entryCount;
}

/*
 * Every so often, walked the linked list
 * and figure out how many lines one string
 * appears (given as the startup param)
 */
DWORD WINAPI SearchThreadFunc(LPVOID n)
{
	int i;
	char *szSearch = (char *)n;

	for (i=0; i<20; i++)
	{
		int		nFoundCount = 0;
		Node   *next = NULL;

		AcquireReadLock(&gpList->lock);
		next = Next(gpList, next);
		while (next)
		{
			if (strstr(next->szBuffer, szSearch))
				nFoundCount++;
			next = Next(gpList, next);
		}

		ReleaseReadLock(&gpList->lock);

		printf("Found %d lines with '%s'\n", nFoundCount, szSearch);
		Sleep((rand() % 30));
	}
    return 0;
}

/* Returns the "afs exporter" structure of type, "type". NULL is returned if not found */
struct afs_exporter *
exporter_find(int type)
{
    struct afs_exporter *op;

    AFS_STATCNT(exporter_add);
    ObtainReadLock(&afs_xexp);
    for (op = root_exported; op; op = op->exp_next) {
        if (op->exp_type == type) {
            ReleaseReadLock(&afs_xexp);
            return op;
        }
    }
    ReleaseReadLock(&afs_xexp);
    return (struct afs_exporter *)0;
}

/*
 * Invalidate the /afs vnode for dynroot; called when the underlying
 * directory has changed and needs to be re-read.
 */
void
afs_DynrootInvalidate(void)
{
    afs_int32 retry;
    struct vcache *tvc;
    struct VenusFid tfid;

    if (!afs_dynrootEnable)
	return;

    ObtainWriteLock(&afs_dynrootDirLock, 687);
    afs_dynrootVersion++;
    afs_dynrootVersionHigh = osi_Time();
    ReleaseWriteLock(&afs_dynrootDirLock);

    afs_GetDynrootFid(&tfid);
    do {
	retry = 0;
	ObtainReadLock(&afs_xvcache);
	tvc = afs_FindVCache(&tfid, &retry, 0);
	ReleaseReadLock(&afs_xvcache);
    } while (retry);
    if (tvc) {
	tvc->f.states &= ~(CStatd | CUnique);
	osi_dnlc_purgedp(tvc);
	afs_PutVCache(tvc);
    }
}