C++ ReleaseWriteLock函数代码示例

/*!
 * Create new cell alias entry and update dynroot vnode.
 * \param alias
 * \param cell
 * \return
 */
afs_int32
afs_NewCellAlias(char *alias, char *cell)
{
    struct cell_alias *tc;

    ObtainSharedLock(&afs_xcell, 681);
    if (afs_CellOrAliasExists_nl(alias)) {
	ReleaseSharedLock(&afs_xcell);
	return EEXIST;
    }

    UpgradeSToWLock(&afs_xcell, 682);
    tc = afs_osi_Alloc(sizeof(struct cell_alias));
    osi_Assert(tc != NULL);
    tc->alias = afs_strdup(alias);
    tc->cell = afs_strdup(cell);
    tc->next = afs_cellalias_head;
    tc->index = afs_cellalias_index++;
    afs_cellalias_head = tc;
    ReleaseWriteLock(&afs_xcell);

    afs_DynrootInvalidate();
    return 0;
}

int
osi_UFSTruncate(struct osi_file *afile, afs_int32 asize)
{
    afs_ucred_t *oldCred;
    struct vattr tvattr;
    afs_int32 code;
    struct osi_stat tstat;
    AFS_STATCNT(osi_Truncate);

    /* This routine only shrinks files, and most systems
     * have very slow truncates, even when the file is already
     * small enough.  Check now and save some time.
     */
    code = afs_osi_Stat(afile, &tstat);
    if (code || tstat.size <= asize)
	return code;
    ObtainWriteLock(&afs_xosi, 321);
    tvattr.va_mask = AT_SIZE;
    tvattr.va_size = asize;
    /*
     * The only time a flag is used (ATTR_UTIME) is when we're changing the time 
     */
    AFS_GUNLOCK();
#ifdef AFS_SUN510_ENV
    {
	caller_context_t ct;

	code = VOP_SETATTR(afile->vnode, &tvattr, 0, afs_osi_credp, &ct);
    }
#else
    code = VOP_SETATTR(afile->vnode, &tvattr, 0, afs_osi_credp);
#endif
    AFS_GLOCK();
    ReleaseWriteLock(&afs_xosi);
    return code;
}

int
afs_osi_Stat(struct osi_file *afile, struct osi_stat *astat)
{
    afs_int32 code;
    struct vattr tvattr;
    AFS_STATCNT(osi_Stat);
    ObtainWriteLock(&afs_xosi, 320);
    /* Ufs doesn't seem to care about the flags so we pass 0 for now */
    tvattr.va_mask = AT_ALL;
    AFS_GUNLOCK();
#ifdef AFS_SUN511_ENV 
    code = VOP_GETATTR(afile->vnode, &tvattr, 0, afs_osi_credp, NULL);
#else
    code = VOP_GETATTR(afile->vnode, &tvattr, 0, afs_osi_credp);
#endif
    AFS_GLOCK();
    if (code == 0) {
	astat->size = tvattr.va_size;
	astat->mtime = tvattr.va_mtime.tv_sec;
	astat->atime = tvattr.va_atime.tv_sec;
    }
    ReleaseWriteLock(&afs_xosi);
    return code;
}

/* afs_FlushCBs 
 * to be used only in dire circumstances, this drops all callbacks on
 * the floor, without giving them back to the server.  It's ok, the server can 
 * deal with it, but it is a little bit rude.
 */
void
afs_FlushCBs(void)
{
    register int i;
    register struct vcache *tvc;

    ObtainWriteLock(&afs_xcbhash, 86);	/* pretty likely I'm going to remove something */

    for (i = 0; i < VCSIZE; i++)	/* reset all the vnodes */
	for (tvc = afs_vhashT[i]; tvc; tvc = tvc->hnext) {
	    tvc->callback = 0;
	    tvc->dchint = NULL;	/* invalidate hints */
	    tvc->f.states &= ~(CStatd);
	    if (QPrev(&(tvc->callsort)))
		QRemove(&(tvc->callsort));
	    if (!(tvc->f.states & (CVInit|CVFlushed)) &&
                ((tvc->f.fid.Fid.Vnode & 1) || (vType(tvc) == VDIR)))
		osi_dnlc_purgedp(tvc);
	}

    afs_InitCBQueue(0);

    ReleaseWriteLock(&afs_xcbhash);
}

/**
 *
 * @param volid Volume ID. If it's 0, get it from the name.
 * @param aname Volume name.
 * @param ve Volume entry.
 * @param tcell The cell containing this volume.
 * @param agood
 * @param type Type of volume.
 * @param areq Request.
 * @return Volume or NULL if failure.
 */
static struct volume *
afs_SetupVolume(afs_int32 volid, char *aname, void *ve, struct cell *tcell,
		afs_int32 agood, afs_int32 type, struct vrequest *areq)
{
    struct volume *tv;
    struct vldbentry *ove = (struct vldbentry *)ve;
    struct nvldbentry *nve = (struct nvldbentry *)ve;
    struct uvldbentry *uve = (struct uvldbentry *)ve;

    int whichType;		/* which type of volume to look for */
    int i, j, err = 0;

    if (!volid) {
	int len;
	/* special hint from file server to use vlserver */
	len = strlen(aname);
	if (len >= 8 && strcmp(aname + len - 7, ".backup") == 0)
	    whichType = BACKVOL;
	else if (len >= 10 && strcmp(aname + len - 9, ".readonly") == 0)
	    whichType = ROVOL;
	else
	    whichType = RWVOL;

	/* figure out which one we're really interested in (a set is returned) */
	volid = afs_vtoi(aname);
	if (volid == 0) {
	    if (type == 2) {
		volid = uve->volumeId[whichType];
	    } else if (type == 1) {
		volid = nve->volumeId[whichType];
	    } else {
		volid = ove->volumeId[whichType];
	    }
	} /* end of if (volid == 0) */
    } /* end of if (!volid) */


    ObtainWriteLock(&afs_xvolume, 108);
    i = VHash(volid);
    for (tv = afs_volumes[i]; tv; tv = tv->next) {
	if (tv->volume == volid && tv->cell == tcell->cellNum) {
	    break;
	}
    }
    if (!tv) {
	struct fvolume *tf = 0;

	tv = afs_GetVolSlot();
	if (!tv) {
	    ReleaseWriteLock(&afs_xvolume);
	    return NULL;
	}
	memset(tv, 0, sizeof(struct volume));

	for (j = fvTable[FVHash(tcell->cellNum, volid)]; j != 0; j = tf->next) {
	    if (afs_FVIndex != j) {
		struct osi_file *tfile;
	        tfile = osi_UFSOpen(&volumeInode);
		err =
		    afs_osi_Read(tfile, sizeof(struct fvolume) * j,
				 &staticFVolume, sizeof(struct fvolume));
		osi_UFSClose(tfile);
                if (err != sizeof(struct fvolume)) {
                    afs_warn("afs_SetupVolume: error %d reading volumeinfo\n",
                             (int)err);
                    /* put tv back on the free list; the data in it is not valid */
                    tv->next = afs_freeVolList;
                    afs_freeVolList = tv;
                    /* staticFVolume contents are not valid */
                    afs_FVIndex = -1;
                    ReleaseWriteLock(&afs_xvolume);
                    return NULL;
                }
		afs_FVIndex = j;
	    }
	    tf = &staticFVolume;
	    if (tf->cell == tcell->cellNum && tf->volume == volid)
		break;
	}

        tv->cell = tcell->cellNum;
        AFS_RWLOCK_INIT(&tv->lock, "volume lock");
        tv->next = afs_volumes[i];      /* thread into list */
        afs_volumes[i] = tv;
        tv->volume = volid;

	if (tf && (j != 0)) {
	    tv->vtix = afs_FVIndex;
	    tv->mtpoint = tf->mtpoint;
//.........这里部分代码省略.........

/*
 * This is almost exactly like the PFlush() routine in afs_pioctl.c,
 * but that routine is static.  We are about to change a file from
 * normal caching to bypass it's caching.  Therefore, we want to
 * free up any cache space in use by the file, and throw out any
 * existing VM pages for the file.  We keep track of the number of
 * times we go back and forth from caching to bypass.
 */
void
afs_TransitionToBypass(struct vcache *avc,
		       afs_ucred_t *acred, int aflags)
{

    afs_int32 code;
    struct vrequest treq;
    int setDesire = 0;
    int setManual = 0;

    if (!avc)
	return;

    if (aflags & TRANSChangeDesiredBit)
	setDesire = 1;
    if (aflags & TRANSSetManualBit)
	setManual = 1;

#ifdef AFS_BOZONLOCK_ENV
    afs_BozonLock(&avc->pvnLock, avc);	/* Since afs_TryToSmush will do a pvn_vptrunc */
#else
    AFS_GLOCK();
#endif

    ObtainWriteLock(&avc->lock, 925);
    /*
     * Someone may have beat us to doing the transition - we had no lock
     * when we checked the flag earlier.  No cause to panic, just return.
     */
    if (avc->cachingStates & FCSBypass)
	goto done;

    /* If we never cached this, just change state */
    if (setDesire && (!(avc->cachingStates & FCSBypass))) {
	avc->cachingStates |= FCSBypass;
	goto done;
    }

    /* cg2v, try to store any chunks not written 20071204 */
    if (avc->execsOrWriters > 0) {
	code = afs_InitReq(&treq, acred);
	if (!code)
	    code = afs_StoreAllSegments(avc, &treq, AFS_SYNC | AFS_LASTSTORE);
    }

#if 0
    /* also cg2v, don't dequeue the callback */
    ObtainWriteLock(&afs_xcbhash, 956);
    afs_DequeueCallback(avc);
    ReleaseWriteLock(&afs_xcbhash);
#endif
    avc->f.states &= ~(CStatd | CDirty);      /* next reference will re-stat */
    /* now find the disk cache entries */
    afs_TryToSmush(avc, acred, 1);
    osi_dnlc_purgedp(avc);
    if (avc->linkData && !(avc->f.states & CCore)) {
	afs_osi_Free(avc->linkData, strlen(avc->linkData) + 1);
	avc->linkData = NULL;
    }

    avc->cachingStates |= FCSBypass;    /* Set the bypass flag */
    if(setDesire)
	avc->cachingStates |= FCSDesireBypass;
    if(setManual)
	avc->cachingStates |= FCSManuallySet;
    avc->cachingTransitions++;

done:
    ReleaseWriteLock(&avc->lock);
#ifdef AFS_BOZONLOCK_ENV
    afs_BozonUnlock(&avc->pvnLock, avc);
#else
    AFS_GUNLOCK();
#endif
}

int
afs_InvalidateAllSegments(struct vcache *avc)
{
    struct dcache *tdc;
    afs_int32 hash;
    afs_int32 index;
    struct dcache **dcList;
    int i, dcListMax, dcListCount;

    AFS_STATCNT(afs_InvalidateAllSegments);
    afs_Trace2(afs_iclSetp, CM_TRACE_INVALL, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(avc->f.m.Length));
    hash = DVHash(&avc->f.fid);
    avc->f.truncPos = AFS_NOTRUNC;	/* don't truncate later */
    avc->f.states &= ~CExtendedFile;	/* not any more */
    ObtainWriteLock(&afs_xcbhash, 459);
    afs_DequeueCallback(avc);
    avc->f.states &= ~(CStatd | CDirty);	/* mark status information as bad, too */
    ReleaseWriteLock(&afs_xcbhash);
    if (avc->f.fid.Fid.Vnode & 1 || (vType(avc) == VDIR))
	osi_dnlc_purgedp(avc);
    /* Blow away pages; for now, only for Solaris */
#if	(defined(AFS_SUN5_ENV))
    if (WriteLocked(&avc->lock))
	osi_ReleaseVM(avc, (afs_ucred_t *)0);
#endif
    /*
     * Block out others from screwing with this table; is a read lock
     * sufficient?
     */
    ObtainWriteLock(&afs_xdcache, 286);
    dcListMax = 0;

    for (index = afs_dvhashTbl[hash]; index != NULLIDX;) {
	if (afs_indexUnique[index] == avc->f.fid.Fid.Unique) {
	    tdc = afs_GetValidDSlot(index);
	    if (!tdc) {
		/* In the case of fatal errors during stores, we MUST
		 * invalidate all of the relevant chunks. Otherwise, the chunks
		 * will be left with the 'new' data that was never successfully
		 * written to the server, but the DV in the dcache is still the
		 * old DV. So, we may indefinitely serve data to applications
		 * that is not actually in the file on the fileserver. If we
		 * cannot afs_GetValidDSlot the appropriate entries, currently
		 * there is no way to ensure the dcache is invalidated. So for
		 * now, to avoid risking serving bad data from the cache, panic
		 * instead. */
		osi_Panic("afs_InvalidateAllSegments tdc count");
	    }
	    ReleaseReadLock(&tdc->tlock);
	    if (!FidCmp(&tdc->f.fid, &avc->f.fid))
		dcListMax++;
	    afs_PutDCache(tdc);
	}
	index = afs_dvnextTbl[index];
    }

    dcList = osi_Alloc(dcListMax * sizeof(struct dcache *));
    dcListCount = 0;

    for (index = afs_dvhashTbl[hash]; index != NULLIDX;) {
	if (afs_indexUnique[index] == avc->f.fid.Fid.Unique) {
	    tdc = afs_GetValidDSlot(index);
	    if (!tdc) {
		/* We cannot proceed after getting this error; we risk serving
		 * incorrect data to applications. So panic instead. See the
		 * above comment next to the previous afs_GetValidDSlot call
		 * for details. */
		osi_Panic("afs_InvalidateAllSegments tdc store");
	    }
	    ReleaseReadLock(&tdc->tlock);
	    if (!FidCmp(&tdc->f.fid, &avc->f.fid)) {
		/* same file? we'll zap it */
		if (afs_indexFlags[index] & IFDataMod) {
		    afs_stats_cmperf.cacheCurrDirtyChunks--;
		    /* don't write it back */
		    afs_indexFlags[index] &= ~IFDataMod;
		}
		afs_indexFlags[index] &= ~IFAnyPages;
		if (dcListCount < dcListMax)
		    dcList[dcListCount++] = tdc;
		else
		    afs_PutDCache(tdc);
	    } else {
		afs_PutDCache(tdc);
	    }
	}
	index = afs_dvnextTbl[index];
    }
    ReleaseWriteLock(&afs_xdcache);

    for (i = 0; i < dcListCount; i++) {
	tdc = dcList[i];

	ObtainWriteLock(&tdc->lock, 679);
	ZapDCE(tdc);
	if (vType(avc) == VDIR)
	    DZap(tdc);
	ReleaseWriteLock(&tdc->lock);
	afs_PutDCache(tdc);
//.........这里部分代码省略.........

void
unlock_cmdLine(void)
{
    ReleaseWriteLock(&cmdLineLock);
}

//.........这里部分代码省略.........
	    ObtainReadLock(&tdc->lock);
	    /* now, first try to start transfer, if we'll need the data.  If
	     * data already coming, we don't need to do this, obviously.  Type
	     * 2 requests never return a null dcache entry, btw.
	     */
	    if (!(tdc->dflags & DFFetching)
		&& !hsame(avc->f.m.DataVersion, tdc->f.versionNo)) {
		/* have cache entry, it is not coming in now,
		 * and we'll need new data */
	      tagain:
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
		if (trybusy && (!afs_BBusy() || (afs_protocols & VICEP_ACCESS))) {
#else
		if (trybusy && !afs_BBusy()) {
#endif
		    struct brequest *bp;
		    /* daemon is not busy */
		    ObtainSharedLock(&tdc->mflock, 665);
		    if (!(tdc->mflags & DFFetchReq)) {
			int dontwait = B_DONTWAIT;
			/* start the daemon (may already be running, however) */
			UpgradeSToWLock(&tdc->mflock, 666);
			tdc->mflags |= DFFetchReq;
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
			if (afs_protocols & VICEP_ACCESS)
			    dontwait = 0;
#endif
			bp = afs_BQueue(BOP_FETCH, avc, dontwait, 0, acred,
					(afs_size_t) filePos, (afs_size_t) 0,
					tdc, (void *)0, (void *)0);
			if (!bp) {
			    tdc->mflags &= ~DFFetchReq;
			    trybusy = 0;	/* Avoid bkg daemon since they're too busy */
			    ReleaseWriteLock(&tdc->mflock);
			    goto tagain;
			}
			ConvertWToSLock(&tdc->mflock);
			/* don't use bp pointer! */
		    }
		    code = 0;
		    ConvertSToRLock(&tdc->mflock);
		    while (!code && tdc->mflags & DFFetchReq) {
			afs_Trace4(afs_iclSetp, CM_TRACE_DCACHEWAIT,
				   ICL_TYPE_STRING, __FILE__, ICL_TYPE_INT32,
				   __LINE__, ICL_TYPE_POINTER, tdc,
				   ICL_TYPE_INT32, tdc->dflags);
			/* don't need waiting flag on this one */
			ReleaseReadLock(&tdc->mflock);
			ReleaseReadLock(&tdc->lock);
			ReleaseReadLock(&avc->lock);
			code = afs_osi_SleepSig(&tdc->validPos);
			ObtainReadLock(&avc->lock);
			ObtainReadLock(&tdc->lock);
			ObtainReadLock(&tdc->mflock);
		    }
		    ReleaseReadLock(&tdc->mflock);
		    if (code) {
			error = code;
			break;
		    }
		}
	    }
	    /* now data may have started flowing in (if DFFetching is on).  If
	     * data is now streaming in, then wait for some interesting stuff.
	     */
	    code = 0;

//.........这里部分代码省略.........

	afs_osi_Free(dotCell, dotLen);
	afs_PutCellAlias(ca);
    }
    maxaliasidx = aliasidx;

    ObtainReadLock(&afs_dynSymlinkLock);
    ts = afs_dynSymlinkBase;
    while (ts) {
	afs_dynroot_computeDirEnt(ts->name, &curPage, &curChunk);
	ts = ts->next;
    }

    dirSize = (curPage + 1) * AFS_PAGESIZE;
    newDir = afs_osi_Alloc(dirSize);

    /*
     * Now actually construct the directory.
     */
    curChunk = 13;
    curPage = 0;
    dirHeader = (struct DirHeader *)newDir;

    dirHeader->header.pgcount = 0;
    dirHeader->header.tag = htons(1234);
    dirHeader->header.freecount = 0;

    dirHeader->header.freebitmap[0] = 0xff;
    dirHeader->header.freebitmap[1] = 0x1f;
    for (i = 2; i < EPP / 8; i++)
	dirHeader->header.freebitmap[i] = 0;
    dirHeader->alloMap[0] = EPP - DHE - 1;
    for (i = 1; i < MAXPAGES; i++)
	dirHeader->alloMap[i] = EPP;
    for (i = 0; i < NHASHENT; i++)
	dirHeader->hashTable[i] = 0;

    /* Install ".", "..", and the dynamic mount directory */
    afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, ".", 1);
    afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, "..", 1);
    afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk,
			  AFS_DYNROOT_MOUNTNAME, AFS_DYNROOT_MOUNT_VNODE);
    linkCount += 3;

    for (cellidx = 0; cellidx < maxcellidx; cellidx++) {
	c = afs_GetCellByIndex(cellidx, READ_LOCK);
	if (!c)
	    continue;
	if (c->cellNum == afs_dynrootCell)
	    continue;

	dotLen = strlen(c->cellName) + 2;
	dotCell = afs_osi_Alloc(dotLen);
	strcpy(dotCell, ".");
	afs_strcat(dotCell, c->cellName);
	afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, c->cellName,
			      VNUM_FROM_CIDX_RW(cellidx, 0));
	afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, dotCell,
			      VNUM_FROM_CIDX_RW(cellidx, 1));
	afs_osi_Free(dotCell, dotLen);

	linkCount += 2;
	afs_PutCell(c, READ_LOCK);
    }

    for (aliasidx = 0; aliasidx < maxaliasidx; aliasidx++) {
	ca = afs_GetCellAlias(aliasidx);
	if (!ca)
	    continue;

	dotLen = strlen(ca->alias) + 2;
	dotCell = afs_osi_Alloc(dotLen);
	strcpy(dotCell, ".");
	afs_strcat(dotCell, ca->alias);
	afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, ca->alias,
			      VNUM_FROM_CAIDX_RW(aliasidx, 0));
	afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, dotCell,
			      VNUM_FROM_CAIDX_RW(aliasidx, 1));
	afs_osi_Free(dotCell, dotLen);
	afs_PutCellAlias(ca);
    }

    ts = afs_dynSymlinkBase;
    while (ts) {
	int vnum = VNUM_FROM_TYPEID(VN_TYPE_SYMLINK, ts->index);
	afs_dynroot_addDirEnt(dirHeader, &curPage, &curChunk, ts->name, vnum);
	ts = ts->next;
    }

    ReleaseReadLock(&afs_dynSymlinkLock);

    ObtainWriteLock(&afs_dynrootDirLock, 549);
    if (afs_dynrootDir)
	afs_osi_Free(afs_dynrootDir, afs_dynrootDirLen);
    afs_dynrootDir = newDir;
    afs_dynrootDirLen = dirSize;
    afs_dynrootDirLinkcnt = linkCount;
    afs_dynrootDirVersion = newVersion;
    ReleaseWriteLock(&afs_dynrootDirLock);
}

int
osi_dnlc_enter(struct vcache *adp, char *aname, struct vcache *avc,
	       afs_hyper_t * avno)
{
    struct nc *tnc;
    unsigned int key, skey;
    char *ts = aname;
    int safety;

    if (!afs_usednlc)
	return 0;

    TRACE(osi_dnlc_enterT, 0);
    dnlcHash(ts, key);		/* leaves ts pointing at the NULL */
    if (ts - aname >= AFSNCNAMESIZE) {
	return 0;
    }
    skey = key & (NHSIZE - 1);
    dnlcstats.enters++;

  retry:
    ObtainWriteLock(&afs_xdnlc, 222);

    /* Only cache entries from the latest version of the directory */
    if (!(adp->f.states & CStatd) || !hsame(*avno, adp->f.m.DataVersion)) {
	ReleaseWriteLock(&afs_xdnlc);
	return 0;
    }

    /*
     * Make sure each directory entry gets cached no more than once.
     */
    for (tnc = nameHash[skey], safety = 0; tnc; tnc = tnc->next, safety++) {
	if ((tnc->dirp == adp) && (!strcmp((char *)tnc->name, aname))) {
	    /* duplicate entry */
	    break;
	} else if (tnc->next == nameHash[skey]) {	/* end of list */
	    tnc = NULL;
	    break;
	} else if (safety > NCSIZE) {
	    afs_warn("DNLC cycle");
	    dnlcstats.cycles++;
	    ReleaseWriteLock(&afs_xdnlc);
	    osi_dnlc_purge();
	    goto retry;
	}
    }

    if (tnc == NULL) {
	tnc = GetMeAnEntry();

	tnc->dirp = adp;
	tnc->vp = avc;
	tnc->key = key;
	memcpy((char *)tnc->name, aname, ts - aname + 1);	/* include the NULL */

	InsertEntry(tnc);
    } else {
	/* duplicate */
	tnc->vp = avc;
    }
    ReleaseWriteLock(&afs_xdnlc);

    return 0;
}

int
DRead(struct dcache *adc, int page, struct DirBuffer *entry)
{
    /* Read a page from the disk. */
    struct buffer *tb, *tb2;
    struct osi_file *tfile;
    int code;

    AFS_STATCNT(DRead);

    memset(entry, 0, sizeof(struct DirBuffer));

    ObtainWriteLock(&afs_bufferLock, 256);

#define bufmatch(tb) (tb->page == page && tb->fid == adc->index)
#define buf_Front(head,parent,p) {(parent)->hashNext = (p)->hashNext; (p)->hashNext= *(head);*(head)=(p);}

    /* this apparently-complicated-looking code is simply an example of
     * a little bit of loop unrolling, and is a standard linked-list
     * traversal trick. It saves a few assignments at the the expense
     * of larger code size.  This could be simplified by better use of
     * macros.
     */
    if ((tb = phTable[pHash(adc->index, page)])) {
	if (bufmatch(tb)) {
	    ObtainWriteLock(&tb->lock, 257);
	    tb->lockers++;
	    ReleaseWriteLock(&afs_bufferLock);
	    tb->accesstime = timecounter++;
	    AFS_STATS(afs_stats_cmperf.bufHits++);
	    ReleaseWriteLock(&tb->lock);
	    entry->buffer = tb;
	    entry->data = tb->data;
	    return 0;
	} else {
	    struct buffer **bufhead;
	    bufhead = &(phTable[pHash(adc->index, page)]);
	    while ((tb2 = tb->hashNext)) {
		if (bufmatch(tb2)) {
		    buf_Front(bufhead, tb, tb2);
		    ObtainWriteLock(&tb2->lock, 258);
		    tb2->lockers++;
		    ReleaseWriteLock(&afs_bufferLock);
		    tb2->accesstime = timecounter++;
		    AFS_STATS(afs_stats_cmperf.bufHits++);
		    ReleaseWriteLock(&tb2->lock);
		    entry->buffer = tb2;
		    entry->data = tb2->data;
		    return 0;
		}
		if ((tb = tb2->hashNext)) {
		    if (bufmatch(tb)) {
			buf_Front(bufhead, tb2, tb);
			ObtainWriteLock(&tb->lock, 259);
			tb->lockers++;
			ReleaseWriteLock(&afs_bufferLock);
			tb->accesstime = timecounter++;
			AFS_STATS(afs_stats_cmperf.bufHits++);
			ReleaseWriteLock(&tb->lock);
			entry->buffer = tb;
			entry->data = tb->data;
			return 0;
		    }
		} else
		    break;
	    }
	}
    } else
	tb2 = NULL;

    AFS_STATS(afs_stats_cmperf.bufMisses++);
    /* can't find it */
    /* The last thing we looked at was either tb or tb2 (or nothing). That
     * is at least the oldest buffer on one particular hash chain, so it's
     * a pretty good place to start looking for the truly oldest buffer.
     */
    tb = afs_newslot(adc, page, (tb ? tb : tb2));
    if (!tb) {
	ReleaseWriteLock(&afs_bufferLock);
	return EIO;
    }
    ObtainWriteLock(&tb->lock, 260);
    tb->lockers++;
    ReleaseWriteLock(&afs_bufferLock);
    if (page * AFS_BUFFER_PAGESIZE >= adc->f.chunkBytes) {
	tb->fid = NULLIDX;
	afs_reset_inode(&tb->inode);
	tb->lockers--;
	ReleaseWriteLock(&tb->lock);
	return EIO;
    }
    tfile = afs_CFileOpen(&adc->f.inode);
    code =
	afs_CFileRead(tfile, tb->page * AFS_BUFFER_PAGESIZE, tb->data,
		      AFS_BUFFER_PAGESIZE);
    afs_CFileClose(tfile);
    if (code < AFS_BUFFER_PAGESIZE) {
	tb->fid = NULLIDX;
	afs_reset_inode(&tb->inode);
	tb->lockers--;
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    }

    if (vType(avc) == VDIR) {
	/* Change fid in the dir for the "." entry. ".." has alredy been
	 * handled by afs_FixChildrenFids when processing the parent dir.
	 */
	tdc = afs_FindDCacheByFid(&avc->f.fid);
	if (tdc) {
   	    afs_dir_ChangeFid(tdc, ".", &avc->f.fid.Fid.Vnode,
			      &newFid.Fid.Vnode);

	    if (avc->f.m.LinkCount >= 2)
	        /* For non empty dirs, fix children's parentVnode and
		 * parentUnique reference.
	     	 */
	    	afs_FixChildrenFids(&avc->f.fid, &newFid);

	    afs_PutDCache(tdc);
	}
    }

    /* Recompute hash chain positions for vnode and dcaches.
     * Then change to the new FID.
     */

    /* The vcache goes first. */
    ObtainWriteLock(&afs_xvcache, 735);

    /* Old fid hash. */
    hash = VCHash(&avc->f.fid);
    /* New fid hash. */
    new_hash = VCHash(&newFid);

    /* Remove hash from old position. */
    /* XXX: not checking array element contents. It shouldn't be empty.
     * If it oopses, then something else might be wrong.
     */
    if (afs_vhashT[hash] == avc) {
        /* First in hash chain (might be the only one). */
	afs_vhashT[hash] = avc->hnext;
    } else {
        /* More elements in hash chain. */
 	for (tvc = afs_vhashT[hash]; tvc; tvc = tvc->hnext) {
	    if (tvc->hnext == avc) {
		tvc->hnext = avc->hnext;
		break;
	    }
        }
    }                           /* if (!afs_vhashT[i]->hnext) */
    QRemove(&avc->vhashq);

    /* Insert hash in new position. */
    avc->hnext = afs_vhashT[new_hash];
    afs_vhashT[new_hash] = avc;
    QAdd(&afs_vhashTV[VCHashV(&newFid)], &avc->vhashq);

    ReleaseWriteLock(&afs_xvcache);

    /* Do the same thing for all dcaches. */
    hash = DVHash(&avc->f.fid);
    ObtainWriteLock(&afs_xdcache, 743);
    for (index = afs_dvhashTbl[hash]; index != NULLIDX; index = hash) {
        hash = afs_dvnextTbl[index];
        tdc = afs_GetValidDSlot(index);
        ReleaseReadLock(&tdc->tlock);
	if (afs_indexUnique[index] == avc->f.fid.Fid.Unique) {
            if (!FidCmp(&tdc->f.fid, &avc->f.fid)) {

		/* Safer but slower. */
 		afs_HashOutDCache(tdc, 0);

                /* Put dcache in new positions in the dchash and dvhash. */
 		new_hash = DCHash(&newFid, tdc->f.chunk);
 		afs_dcnextTbl[tdc->index] = afs_dchashTbl[new_hash];
 		afs_dchashTbl[new_hash] = tdc->index;

 		new_hash = DVHash(&newFid);
 		afs_dvnextTbl[tdc->index] = afs_dvhashTbl[new_hash];
 		afs_dvhashTbl[new_hash] = tdc->index;

 		afs_indexUnique[tdc->index] = newFid.Fid.Unique;
		memcpy(&tdc->f.fid, &newFid, sizeof(struct VenusFid));
           }                   /* if fid match */
	}                       /* if uniquifier match */
    	if (tdc)
	    afs_PutDCache(tdc);
    }                           /* for all dcaches in this hash bucket */
    ReleaseWriteLock(&afs_xdcache);

    /* Now we can set the new fid. */
    memcpy(&avc->f.fid, &newFid, sizeof(struct VenusFid));

end:
    if (tdp)
    	afs_PutVCache(tdp);
    afs_osi_Free(tname, AFSNAMEMAX);
    if (ttargetName)
	afs_osi_Free(ttargetName, tlen);
    return code;
}

/*!
 * All files that have been dirty before disconnection are going to
 * be replayed back to the server.
 *
 * \param areq Request from the user.
 * \param acred User credentials.
 *
 * \return If all files synchronized succesfully, return 0, otherwise
 * return error code
 *
 * \note For now, it's the request from the PDiscon pioctl.
 *
 */
int
afs_ResyncDisconFiles(struct vrequest *areq, afs_ucred_t *acred)
{
    struct afs_conn *tc;
    struct rx_connection *rxconn;
    struct vcache *tvc;
    struct AFSFetchStatus fstat;
    struct AFSCallBack callback;
    struct AFSVolSync tsync;
    int code = 0;
    afs_int32 start = 0;
    XSTATS_DECLS;
    /*AFS_STATCNT(afs_ResyncDisconFiles);*/

    ObtainWriteLock(&afs_disconDirtyLock, 707);

    while (!QEmpty(&afs_disconDirty)) {
	tvc = QEntry(QPrev(&afs_disconDirty), struct vcache, dirtyq);

	/* Can't lock tvc whilst holding the discon dirty lock */
	ReleaseWriteLock(&afs_disconDirtyLock);

	/* Get local write lock. */
	ObtainWriteLock(&tvc->lock, 705);

	if (tvc->f.ddirty_flags & VDisconRemove) {
	    /* Delete the file on the server and just move on
	     * to the next file. After all, it has been deleted
	     * we can't replay any other operation it.
	     */
	    code = afs_ProcessOpRemove(tvc, areq);
	    goto next_file;

	} else if (tvc->f.ddirty_flags & VDisconCreate) {
	    /* For newly created files, we don't need a server lock. */
	    code = afs_ProcessOpCreate(tvc, areq, acred);
	    if (code)
	    	goto next_file;

	    tvc->f.ddirty_flags &= ~VDisconCreate;
	    tvc->f.ddirty_flags |= VDisconCreated;
	}
#if 0
  	/* Get server write lock. */
  	do {
	    tc = afs_Conn(&tvc->f.fid, areq, SHARED_LOCK, &rxconn);
  	    if (tc) {
	    	XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_SETLOCK);
  		RX_AFS_GUNLOCK();
  		code = RXAFS_SetLock(rxconn,
					(struct AFSFid *)&tvc->f.fid.Fid,
					LockWrite,
					&tsync);
		RX_AFS_GLOCK();
		XSTATS_END_TIME;
	   } else
		code = -1;

	} while (afs_Analyze(tc,
			     rxconn,
			     code,
			     &tvc->f.fid,
			     areq,
			     AFS_STATS_FS_RPCIDX_SETLOCK,
			     SHARED_LOCK,
			     NULL));

	if (code)
	    goto next_file;
#endif
	if (tvc->f.ddirty_flags & VDisconRename) {
	    /* If we're renaming the file, do so now */
	    code = afs_ProcessOpRename(tvc, areq);
	    if (code)
	    	goto unlock_srv_file;
	}

	/* Issue a FetchStatus to get info about DV and callbacks. */
	do {
	    tc = afs_Conn(&tvc->f.fid, areq, SHARED_LOCK, &rxconn);
	    if (tc) {
	    	tvc->callback = tc->srvr->server;
		start = osi_Time();
		XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_FETCHSTATUS);
		RX_AFS_GUNLOCK();
		code = RXAFS_FetchStatus(rxconn,
				(struct AFSFid *)&tvc->f.fid.Fid,
//.........这里部分代码省略.........

int
afsremove(register struct vcache *adp, register struct dcache *tdc,
	  register struct vcache *tvc, char *aname, afs_ucred_t *acred,
	  struct vrequest *treqp)
{
    register afs_int32 code = 0;
    register struct afs_conn *tc;
    struct AFSFetchStatus OutDirStatus;
    struct AFSVolSync tsync;
    XSTATS_DECLS;
    if (!AFS_IS_DISCONNECTED) {
        do {
	    tc = afs_Conn(&adp->f.fid, treqp, SHARED_LOCK);
	    if (tc) {
	        XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_REMOVEFILE);
	        RX_AFS_GUNLOCK();
	        code =
		    RXAFS_RemoveFile(tc->id, (struct AFSFid *)&adp->f.fid.Fid,
		  		     aname, &OutDirStatus, &tsync);
	        RX_AFS_GLOCK();
	        XSTATS_END_TIME;
	    } else
	        code = -1;
        } while (afs_Analyze
	         (tc, code, &adp->f.fid, treqp, AFS_STATS_FS_RPCIDX_REMOVEFILE,
	          SHARED_LOCK, NULL));
    }

    osi_dnlc_remove(adp, aname, tvc);

    if (code) {
	if (tdc) {
	    ReleaseSharedLock(&tdc->lock);
	    afs_PutDCache(tdc);
	}

	if (tvc)
	    afs_PutVCache(tvc);

	if (code < 0) {
	    ObtainWriteLock(&afs_xcbhash, 497);
	    afs_DequeueCallback(adp);
	    adp->f.states &= ~CStatd;
	    ReleaseWriteLock(&afs_xcbhash);
	    osi_dnlc_purgedp(adp);
	}
	ReleaseWriteLock(&adp->lock);
	code = afs_CheckCode(code, treqp, 21);
	return code;
    }
    if (tdc)
	UpgradeSToWLock(&tdc->lock, 637);
    if (AFS_IS_DISCON_RW || afs_LocalHero(adp, tdc, &OutDirStatus, 1)) {
	/* we can do it locally */
	code = afs_dir_Delete(tdc, aname);
	if (code) {
	    ZapDCE(tdc);	/* surprise error -- invalid value */
	    DZap(tdc);
	}
    }
    if (tdc) {
	ReleaseWriteLock(&tdc->lock);
	afs_PutDCache(tdc);	/* drop ref count */
    }
    ReleaseWriteLock(&adp->lock);

    /* now, get vnode for unlinked dude, and see if we should force it
     * from cache.  adp is now the deleted files vnode.  Note that we
     * call FindVCache instead of GetVCache since if the file's really
     * gone, we won't be able to fetch the status info anyway.  */
    if (tvc) {
	afs_MarinerLog("store$Removing", tvc);
#ifdef AFS_BOZONLOCK_ENV
	afs_BozonLock(&tvc->pvnLock, tvc);
	/* Since afs_TryToSmush will do a pvn_vptrunc */
#endif
	ObtainWriteLock(&tvc->lock, 141);
	/* note that callback will be broken on the deleted file if there are
	 * still >0 links left to it, so we'll get the stat right */
	tvc->f.m.LinkCount--;
	tvc->f.states &= ~CUnique;	/* For the dfs xlator */
	if (tvc->f.m.LinkCount == 0 && !osi_Active(tvc)) {
	    if (!AFS_NFSXLATORREQ(acred))
		afs_TryToSmush(tvc, acred, 0);
	}
	ReleaseWriteLock(&tvc->lock);
#ifdef AFS_BOZONLOCK_ENV
	afs_BozonUnlock(&tvc->pvnLock, tvc);
#endif
	afs_PutVCache(tvc);
    }
    return (0);
}