Beispiel #1
0
static int
afs_StoreMini(struct vcache *avc, struct vrequest *areq)
{
    struct afs_conn *tc;
    struct AFSStoreStatus InStatus;
    struct AFSFetchStatus OutStatus;
    struct AFSVolSync tsync;
    afs_int32 code;
    struct rx_call *tcall;
    struct rx_connection *rxconn;
    afs_size_t tlen, xlen = 0;
    XSTATS_DECLS;
    AFS_STATCNT(afs_StoreMini);
    afs_Trace2(afs_iclSetp, CM_TRACE_STOREMINI, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_INT32, avc->f.m.Length);
    tlen = avc->f.m.Length;
    if (avc->f.truncPos < tlen)
	tlen = avc->f.truncPos;
    avc->f.truncPos = AFS_NOTRUNC;
    avc->f.states &= ~CExtendedFile;

    do {
	tc = afs_Conn(&avc->f.fid, areq, SHARED_LOCK, &rxconn);
	if (tc) {
#ifdef AFS_64BIT_CLIENT
	  retry:
#endif
	    RX_AFS_GUNLOCK();
	    tcall = rx_NewCall(rxconn);
	    RX_AFS_GLOCK();
	    /* Set the client mod time since we always want the file
	     * to have the client's mod time and not the server's one
	     * (to avoid problems with make, etc.) It almost always
	     * works fine with standard afs because them server/client
	     * times are in sync and more importantly this storemini
	     * it's a special call that would typically be followed by
	     * the proper store-data or store-status calls.
	     */
	    InStatus.Mask = AFS_SETMODTIME;
	    InStatus.ClientModTime = avc->f.m.Date;
	    XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_STOREDATA);
	    afs_Trace4(afs_iclSetp, CM_TRACE_STOREDATA64, ICL_TYPE_FID,
		       &avc->f.fid.Fid, ICL_TYPE_OFFSET,
		       ICL_HANDLE_OFFSET(avc->f.m.Length), ICL_TYPE_OFFSET,
		       ICL_HANDLE_OFFSET(xlen), ICL_TYPE_OFFSET,
		       ICL_HANDLE_OFFSET(tlen));
	    RX_AFS_GUNLOCK();
#ifdef AFS_64BIT_CLIENT
	    if (!afs_serverHasNo64Bit(tc)) {
		code =
		    StartRXAFS_StoreData64(tcall,
					   (struct AFSFid *)&avc->f.fid.Fid,
					   &InStatus, avc->f.m.Length,
					   (afs_size_t) 0, tlen);
	    } else {
		afs_int32 l1, l2;
		l1 = avc->f.m.Length;
		l2 = tlen;
		if ((avc->f.m.Length > 0x7fffffff) ||
		    (tlen > 0x7fffffff) ||
		    ((0x7fffffff - tlen) < avc->f.m.Length)) {
		    code = EFBIG;
		    goto error;
		}
		code =
		    StartRXAFS_StoreData(tcall,
					 (struct AFSFid *)&avc->f.fid.Fid,
					 &InStatus, l1, 0, l2);
	    }
#else /* AFS_64BIT_CLIENT */
	    code =
		StartRXAFS_StoreData(tcall, (struct AFSFid *)&avc->f.fid.Fid,
				     &InStatus, avc->f.m.Length, 0, tlen);
#endif /* AFS_64BIT_CLIENT */
	    if (code == 0) {
		code = EndRXAFS_StoreData(tcall, &OutStatus, &tsync);
	    }
#ifdef AFS_64BIT_CLIENT
	error:
#endif
	    code = rx_EndCall(tcall, code);
	    RX_AFS_GLOCK();
	    XSTATS_END_TIME;
#ifdef AFS_64BIT_CLIENT
	    if (code == RXGEN_OPCODE && !afs_serverHasNo64Bit(tc)) {
		afs_serverSetNo64Bit(tc);
		goto retry;
	    }
#endif /* AFS_64BIT_CLIENT */
	} else
	    code = -1;
    } while (afs_Analyze
	     (tc, rxconn, code, &avc->f.fid, areq, AFS_STATS_FS_RPCIDX_STOREDATA,
	      SHARED_LOCK, NULL));

    if (code == 0)
	afs_ProcessFS(avc, &OutStatus, areq);

    return code;
}				/*afs_StoreMini */
Beispiel #2
0
int
afs_MemRead(struct vcache *avc, struct uio *auio,
	    afs_ucred_t *acred, daddr_t albn, struct buf **abpp,
	    int noLock)
{
    afs_size_t totalLength;
    afs_size_t transferLength;
    afs_size_t filePos;
    afs_size_t offset, tlen;
    afs_size_t len = 0;
    afs_int32 trimlen;
    struct dcache *tdc = 0;
    afs_int32 error, trybusy = 1;
    afs_int32 code;
    struct vrequest *treq = NULL;
#ifdef AFS_DARWIN80_ENV
    uio_t tuiop = NULL;
#else
    struct uio tuio;
    struct uio *tuiop = &tuio;
    struct iovec *tvec;
    memset(&tuio, 0, sizeof(tuio));
#endif

    AFS_STATCNT(afs_MemRead);
    if (avc->vc_error)
	return EIO;

    /* check that we have the latest status info in the vnode cache */
    if ((code = afs_CreateReq(&treq, acred)))
	return code;
    if (!noLock) {
	code = afs_VerifyVCache(avc, treq);
	if (code) {
	    code = afs_CheckCode(code, treq, 8);	/* failed to get it */
	    afs_DestroyReq(treq);
	    return code;
	}
    }
#ifndef	AFS_VM_RDWR_ENV
    if (AFS_NFSXLATORREQ(acred)) {
	if (!afs_AccessOK
	    (avc, PRSFS_READ, treq,
	     CHECK_MODE_BITS | CMB_ALLOW_EXEC_AS_READ)) {
	    code = afs_CheckCode(EACCES, treq, 9);
	    afs_DestroyReq(treq);
	    return code;
	}
    }
#endif

#ifndef AFS_DARWIN80_ENV
    tvec = (struct iovec *)osi_AllocSmallSpace(sizeof(struct iovec));
    memset(tvec, 0, sizeof(struct iovec));
#endif
    totalLength = AFS_UIO_RESID(auio);
    filePos = AFS_UIO_OFFSET(auio);
    afs_Trace4(afs_iclSetp, CM_TRACE_READ, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(filePos), ICL_TYPE_INT32,
	       totalLength, ICL_TYPE_OFFSET,
	       ICL_HANDLE_OFFSET(avc->f.m.Length));
    error = 0;
    transferLength = 0;
    if (!noLock)
	ObtainReadLock(&avc->lock);
#if	defined(AFS_TEXT_ENV) && !defined(AFS_VM_RDWR_ENV)
    if (avc->flushDV.high == AFS_MAXDV && avc->flushDV.low == AFS_MAXDV) {
	hset(avc->flushDV, avc->f.m.DataVersion);
    }
#endif

    /*
     * Locks held:
     * avc->lock(R)
     */

    /* This bit is bogus. We're checking to see if the read goes past the
     * end of the file. If so, we should be zeroing out all of the buffers
     * that the client has passed into us (there is a danger that we may leak
     * kernel memory if we do not). However, this behaviour is disabled by
     * not setting len before this segment runs, and by setting len to 0
     * immediately we enter it. In addition, we also need to check for a read
     * which partially goes off the end of the file in the while loop below.
     */

    if (filePos >= avc->f.m.Length) {
	if (len > AFS_ZEROS)
	    len = sizeof(afs_zeros);	/* and in 0 buffer */
	len = 0;
#ifdef AFS_DARWIN80_ENV
	trimlen = len;
	tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
	afsio_copy(auio, &tuio, tvec);
	trimlen = len;
	afsio_trim(&tuio, trimlen);
#endif
	AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
    }

    while (avc->f.m.Length > 0 && totalLength > 0) {
	/* read all of the cached info */
	if (filePos >= avc->f.m.Length)
	    break;		/* all done */
	if (noLock) {
	    if (tdc) {
		ReleaseReadLock(&tdc->lock);
		afs_PutDCache(tdc);
	    }
	    tdc = afs_FindDCache(avc, filePos);
	    if (tdc) {
		ObtainReadLock(&tdc->lock);
		offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
		len = tdc->f.chunkBytes - offset;
	    }
	} else {
	    int versionOk;
	    /* a tricky question: does the presence of the DFFetching flag
	     * mean that we're fetching the latest version of the file?  No.
	     * The server could update the file as soon as the fetch responsible
	     * for the setting of the DFFetching flag completes.
	     *
	     * However, the presence of the DFFetching flag (visible under
	     * a dcache read lock since it is set and cleared only under a
	     * dcache write lock) means that we're fetching as good a version
	     * as was known to this client at the time of the last call to
	     * afs_VerifyVCache, since the latter updates the stat cache's
	     * m.DataVersion field under a vcache write lock, and from the
	     * time that the DFFetching flag goes on in afs_GetDCache (before
	     * the fetch starts), to the time it goes off (after the fetch
	     * completes), afs_GetDCache keeps at least a read lock on the
	     * vcache entry.
	     *
	     * This means that if the DFFetching flag is set, we can use that
	     * data for any reads that must come from the current version of
	     * the file (current == m.DataVersion).
	     *
	     * Another way of looking at this same point is this: if we're
	     * fetching some data and then try do an afs_VerifyVCache, the
	     * VerifyVCache operation will not complete until after the
	     * DFFetching flag is turned off and the dcache entry's f.versionNo
	     * field is updated.
	     *
	     * Note, by the way, that if DFFetching is set,
	     * m.DataVersion > f.versionNo (the latter is not updated until
	     * after the fetch completes).
	     */
	    if (tdc) {
		ReleaseReadLock(&tdc->lock);
		afs_PutDCache(tdc);	/* before reusing tdc */
	    }
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
    try_background:
#endif
	    tdc = afs_GetDCache(avc, filePos, treq, &offset, &len, 2);
	    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;
	    while (!code && (tdc->dflags & DFFetching)
		   && tdc->validPos <= filePos) {
		/* too early: wait for DFFetching flag to vanish,
		 * or data to appear */
		afs_Trace4(afs_iclSetp, CM_TRACE_DCACHEWAIT, ICL_TYPE_STRING,
			   __FILE__, ICL_TYPE_INT32, __LINE__,
			   ICL_TYPE_POINTER, tdc, ICL_TYPE_INT32,
			   tdc->dflags);
		ReleaseReadLock(&tdc->lock);
		ReleaseReadLock(&avc->lock);
		code = afs_osi_SleepSig(&tdc->validPos);
		ObtainReadLock(&avc->lock);
		ObtainReadLock(&tdc->lock);
	    }
	    if (code) {
		error = code;
		break;
	    }
	    /* fetching flag gone, data is here, or we never tried
	     * (BBusy for instance) */
	    len = tdc->validPos - filePos;
	    versionOk = hsame(avc->f.m.DataVersion, tdc->f.versionNo) ? 1 : 0;
	    if (tdc->dflags & DFFetching) {
		/* still fetching, some new data is here:
		 * compute length and offset */
		offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
	    } else {
		/* no longer fetching, verify data version
		 * (avoid new GetDCache call) */
		if (versionOk && len > 0) {
		    offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
		} else {
		    /* don't have current data, so get it below */
		    afs_Trace3(afs_iclSetp, CM_TRACE_VERSIONNO,
			       ICL_TYPE_INT64, ICL_HANDLE_OFFSET(filePos),
			       ICL_TYPE_HYPER, &avc->f.m.DataVersion,
			       ICL_TYPE_HYPER, &tdc->f.versionNo);
#if 0
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
if (afs_protocols & VICEP_ACCESS) {
printf("afs_read: DV mismatch? %d instead of %d for %u.%u.%u\n", tdc->f.versionNo.low, avc->f.m.DataVersion.low, avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
printf("afs_read: validPos %llu filePos %llu totalLength %lld m.Length %llu noLock %d\n", tdc->validPos, filePos, totalLength, avc->f.m.Length, noLock);
printf("afs_read: or len too low? %lld for %u.%u.%u\n", len, avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
}
#endif
#endif
		    ReleaseReadLock(&tdc->lock);
		    afs_PutDCache(tdc);
		    tdc = NULL;
		}
	    }

	    if (!tdc) {
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
		if (afs_protocols & VICEP_ACCESS) { /* avoid foreground fetch */
		    if (!versionOk) {
printf("afs_read: avoid forground %u.%u.%u\n", avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
		        goto try_background;
		    }
#if 0
printf("afs_read: forground %u.%u.%u\n", avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
#endif
		}
#endif
		/* If we get here, it was not possible to start the
		 * background daemon. With flag == 1 afs_GetDCache
		 * does the FetchData rpc synchronously.
		 */
		ReleaseReadLock(&avc->lock);
		tdc = afs_GetDCache(avc, filePos, treq, &offset, &len, 1);
		ObtainReadLock(&avc->lock);
		if (tdc)
		    ObtainReadLock(&tdc->lock);
	    }
	}

	afs_Trace3(afs_iclSetp, CM_TRACE_VNODEREAD, ICL_TYPE_POINTER, tdc,
		   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(offset),
		   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(len));
	if (!tdc) {
	    error = EIO;
	    break;
	}

	/*
	 * Locks held:
	 * avc->lock(R)
	 * tdc->lock(R)
	 */

	if (len > totalLength)
	    len = totalLength;	/* will read len bytes */
	if (len <= 0) {		/* shouldn't get here if DFFetching is on */
	    /* read past the end of a chunk, may not be at next chunk yet, and yet
	     * also not at eof, so may have to supply fake zeros */
	    len = AFS_CHUNKTOSIZE(tdc->f.chunk) - offset;	/* bytes left in chunk addr space */
	    if (len > totalLength)
		len = totalLength;	/* and still within xfr request */
	    tlen = avc->f.m.Length - offset;	/* and still within file */
	    if (len > tlen)
		len = tlen;
	    if (len > AFS_ZEROS)
		len = sizeof(afs_zeros);	/* and in 0 buffer */
#ifdef AFS_DARWIN80_ENV
	    trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
	    afsio_copy(auio, &tuio, tvec);
	    trimlen = len;
	    afsio_trim(&tuio, trimlen);
#endif
	        AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
	    if (code) {
		error = code;
		break;
	    }
	} else {
	    /* get the data from the mem cache */

	    /* mung uio structure to be right for this transfer */
#ifdef AFS_DARWIN80_ENV
	    trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
	    uio_setoffset(tuiop, offset);
#else
	    afsio_copy(auio, &tuio, tvec);
	    trimlen = len;
	    afsio_trim(&tuio, trimlen);
	    tuio.afsio_offset = offset;
#endif

	    code = afs_MemReadUIO(&tdc->f.inode, tuiop);

	    if (code) {
		error = code;
		break;
	    }
	}
	/* otherwise we've read some, fixup length, etc and continue with next seg */
	len = len - AFS_UIO_RESID(tuiop);	/* compute amount really transferred */
	trimlen = len;
	afsio_skip(auio, trimlen);	/* update input uio structure */
	totalLength -= len;
	transferLength += len;
	filePos += len;

	if (len <= 0)
	    break;		/* surprise eof */
#ifdef AFS_DARWIN80_ENV
	if (tuiop) {
	    uio_free(tuiop);
	    tuiop = 0;
	}
#endif
    }				/* the whole while loop */

    /*
     * Locks held:
     * avc->lock(R)
     * tdc->lock(R) if tdc
     */

    /* if we make it here with tdc non-zero, then it is the last chunk we
     * dealt with, and we have to release it when we're done.  We hold on
     * to it in case we need to do a prefetch.
     */
    if (tdc) {
	ReleaseReadLock(&tdc->lock);
	/*
         * try to queue prefetch, if needed. If DataVersion is zero there
	 * should not be any more: files with DV 0 never have been stored
	 * on the fileserver, symbolic links and directories never require
	 * more than a single chunk.
	 */
	if (!noLock && !(hiszero(avc->f.m.DataVersion)) &&
#ifndef AFS_VM_RDWR_ENV
	    afs_preCache
#else
	    1
#endif
	    ) {
	    afs_PrefetchChunk(avc, tdc, acred, treq);
	}
	afs_PutDCache(tdc);
    }
    if (!noLock)
	ReleaseReadLock(&avc->lock);
#ifdef AFS_DARWIN80_ENV
    if (tuiop)
       uio_free(tuiop);
#else
    osi_FreeSmallSpace(tvec);
#endif
    error = afs_CheckCode(error, treq, 10);
    afs_DestroyReq(treq);
    return error;
}

/* called with the dcache entry triggering the fetch, the vcache entry involved,
 * and a vrequest for the read call.  Marks the dcache entry as having already
 * triggered a prefetch, starts the prefetch going and sets the DFFetchReq
 * flag in the prefetched block, so that the next call to read knows to wait
 * for the daemon to start doing things.
 *
 * This function must be called with the vnode at least read-locked, and
 * no locks on the dcache, because it plays around with dcache entries.
 */
void
afs_PrefetchChunk(struct vcache *avc, struct dcache *adc,
		  afs_ucred_t *acred, struct vrequest *areq)
{
    struct dcache *tdc;
    afs_size_t offset;
    afs_size_t j1, j2;		/* junk vbls for GetDCache to trash */

    offset = adc->f.chunk + 1;	/* next chunk we'll need */
    offset = AFS_CHUNKTOBASE(offset);	/* base of next chunk */
    ObtainReadLock(&adc->lock);
    ObtainSharedLock(&adc->mflock, 662);
    if (offset < avc->f.m.Length && !(adc->mflags & DFNextStarted)
	&& !afs_BBusy()) {
	struct brequest *bp;

	UpgradeSToWLock(&adc->mflock, 663);
	adc->mflags |= DFNextStarted;	/* we've tried to prefetch for this guy */
	ReleaseWriteLock(&adc->mflock);
	ReleaseReadLock(&adc->lock);

	tdc = afs_GetDCache(avc, offset, areq, &j1, &j2, 2);	/* type 2 never returns 0 */
        /*
         * In disconnected mode, type 2 can return 0 because it doesn't
         * make any sense to allocate a dcache we can never fill
         */
         if (tdc == NULL)
             return;

	ObtainSharedLock(&tdc->mflock, 651);
	if (!(tdc->mflags & DFFetchReq)) {
	    /* ask the daemon to do the work */
	    UpgradeSToWLock(&tdc->mflock, 652);
	    tdc->mflags |= DFFetchReq;	/* guaranteed to be cleared by BKG or GetDCache */
	    /* last parm (1) tells bkg daemon to do an afs_PutDCache when it is done,
	     * since we don't want to wait for it to finish before doing so ourselves.
	     */
	    bp = afs_BQueue(BOP_FETCH, avc, B_DONTWAIT, 0, acred,
			    (afs_size_t) offset, (afs_size_t) 1, tdc,
			    (void *)0, (void *)0);
	    if (!bp) {
		/* Bkg table full; just abort non-important prefetching to avoid deadlocks */
		tdc->mflags &= ~DFFetchReq;
		ReleaseWriteLock(&tdc->mflock);
		afs_PutDCache(tdc);

		/*
		 * DCLOCKXXX: This is a little sketchy, since someone else
		 * could have already started a prefetch..  In practice,
		 * this probably doesn't matter; at most it would cause an
		 * extra slot in the BKG table to be used up when someone
		 * prefetches this for the second time.
		 */
		ObtainReadLock(&adc->lock);
		ObtainWriteLock(&adc->mflock, 664);
		adc->mflags &= ~DFNextStarted;
		ReleaseWriteLock(&adc->mflock);
		ReleaseReadLock(&adc->lock);
	    } else {
		ReleaseWriteLock(&tdc->mflock);
	    }
	} else {
	    ReleaseSharedLock(&tdc->mflock);
	    afs_PutDCache(tdc);
	}
    } else {
	ReleaseSharedLock(&adc->mflock);
	ReleaseReadLock(&adc->lock);
    }
}

int
afs_UFSRead(struct vcache *avc, struct uio *auio,
	    afs_ucred_t *acred, daddr_t albn, struct buf **abpp,
	    int noLock)
{
    afs_size_t totalLength;
    afs_size_t transferLength;
    afs_size_t filePos;
    afs_size_t offset, tlen;
    afs_size_t len = 0;
    afs_int32 trimlen;
    struct dcache *tdc = 0;
    afs_int32 error;
    struct osi_file *tfile;
    afs_int32 code;
    int trybusy = 1;
    struct vrequest *treq = NULL;
#ifdef AFS_DARWIN80_ENV
    uio_t tuiop=NULL;
#else
    struct uio tuio;
    struct uio *tuiop = &tuio;
    struct iovec *tvec;
    memset(&tuio, 0, sizeof(tuio));
#endif

    AFS_STATCNT(afs_UFSRead);
    if (avc && avc->vc_error)
	return EIO;

    AFS_DISCON_LOCK();

    /* check that we have the latest status info in the vnode cache */
    if ((code = afs_CreateReq(&treq, acred)))
	return code;
    if (!noLock) {
	if (!avc)
	    osi_Panic("null avc in afs_UFSRead");
	else {
	    code = afs_VerifyVCache(avc, treq);
	    if (code) {
		code = afs_CheckCode(code, treq, 11);	/* failed to get it */
		afs_DestroyReq(treq);
		AFS_DISCON_UNLOCK();
		return code;
	    }
	}
    }
#ifndef	AFS_VM_RDWR_ENV
    if (AFS_NFSXLATORREQ(acred)) {
	if (!afs_AccessOK
	    (avc, PRSFS_READ, treq,
	     CHECK_MODE_BITS | CMB_ALLOW_EXEC_AS_READ)) {
	    AFS_DISCON_UNLOCK();
	    code = afs_CheckCode(EACCES, treq, 12);
	    afs_DestroyReq(treq);
	    return code;
	}
    }
#endif

#ifndef AFS_DARWIN80_ENV
    tvec = (struct iovec *)osi_AllocSmallSpace(sizeof(struct iovec));
    memset(tvec, 0, sizeof(struct iovec));
#endif
    totalLength = AFS_UIO_RESID(auio);
    filePos = AFS_UIO_OFFSET(auio);
    afs_Trace4(afs_iclSetp, CM_TRACE_READ, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(filePos), ICL_TYPE_INT32,
	       totalLength, ICL_TYPE_OFFSET,
	       ICL_HANDLE_OFFSET(avc->f.m.Length));
    error = 0;
    transferLength = 0;
    if (!noLock)
	ObtainReadLock(&avc->lock);
#if	defined(AFS_TEXT_ENV) && !defined(AFS_VM_RDWR_ENV)
    if (avc->flushDV.high == AFS_MAXDV && avc->flushDV.low == AFS_MAXDV) {
	hset(avc->flushDV, avc->f.m.DataVersion);
    }
#endif

    /* This bit is bogus. We're checking to see if the read goes past the
     * end of the file. If so, we should be zeroing out all of the buffers
     * that the client has passed into us (there is a danger that we may leak
     * kernel memory if we do not). However, this behaviour is disabled by
     * not setting len before this segment runs, and by setting len to 0
     * immediately we enter it. In addition, we also need to check for a read
     * which partially goes off the end of the file in the while loop below.
     */

    if (filePos >= avc->f.m.Length) {
	if (len > AFS_ZEROS)
	    len = sizeof(afs_zeros);	/* and in 0 buffer */
	len = 0;
#ifdef AFS_DARWIN80_ENV
	trimlen = len;
	tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
	afsio_copy(auio, &tuio, tvec);
	trimlen = len;
	afsio_trim(&tuio, trimlen);
#endif
	AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
    }

    while (avc->f.m.Length > 0 && totalLength > 0) {
	/* read all of the cached info */
	if (filePos >= avc->f.m.Length)
	    break;		/* all done */
	if (noLock) {
	    if (tdc) {
		ReleaseReadLock(&tdc->lock);
		afs_PutDCache(tdc);
	    }
	    tdc = afs_FindDCache(avc, filePos);
	    if (tdc) {
		ObtainReadLock(&tdc->lock);
		offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
		len = tdc->validPos - filePos;
	    }
	} else {
	    int versionOk;
	    /* a tricky question: does the presence of the DFFetching flag
	     * mean that we're fetching the latest version of the file?  No.
	     * The server could update the file as soon as the fetch responsible
	     * for the setting of the DFFetching flag completes.
	     *
	     * However, the presence of the DFFetching flag (visible under
	     * a dcache read lock since it is set and cleared only under a
	     * dcache write lock) means that we're fetching as good a version
	     * as was known to this client at the time of the last call to
	     * afs_VerifyVCache, since the latter updates the stat cache's
	     * m.DataVersion field under a vcache write lock, and from the
	     * time that the DFFetching flag goes on in afs_GetDCache (before
	     * the fetch starts), to the time it goes off (after the fetch
	     * completes), afs_GetDCache keeps at least a read lock on the
	     * vcache entry.
	     *
	     * This means that if the DFFetching flag is set, we can use that
	     * data for any reads that must come from the current version of
	     * the file (current == m.DataVersion).
	     *
	     * Another way of looking at this same point is this: if we're
	     * fetching some data and then try do an afs_VerifyVCache, the
	     * VerifyVCache operation will not complete until after the
	     * DFFetching flag is turned off and the dcache entry's f.versionNo
	     * field is updated.
	     *
	     * Note, by the way, that if DFFetching is set,
	     * m.DataVersion > f.versionNo (the latter is not updated until
	     * after the fetch completes).
	     */
	    if (tdc) {
		ReleaseReadLock(&tdc->lock);
		afs_PutDCache(tdc);	/* before reusing tdc */
	    }
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
    try_background:
#endif
	    tdc = afs_GetDCache(avc, filePos, treq, &offset, &len, 2);
	    if (!tdc) {
	        error = ENETDOWN;
	        break;
	    }

	    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, 667);
		    if (!(tdc->mflags & DFFetchReq)) {
			int dontwait = B_DONTWAIT;
			UpgradeSToWLock(&tdc->mflock, 668);
			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) {
			    /* Bkg table full; retry deadlocks */
			    tdc->mflags &= ~DFFetchReq;
			    trybusy = 0;	/* Avoid bkg daemon since they're too busy */
			    ReleaseWriteLock(&tdc->mflock);
			    goto tagain;
			}
			ConvertWToSLock(&tdc->mflock);
		    }
		    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;
	    while (!code && (tdc->dflags & DFFetching)
		   && tdc->validPos <= filePos) {
		/* too early: wait for DFFetching flag to vanish,
		 * or data to appear */
		afs_Trace4(afs_iclSetp, CM_TRACE_DCACHEWAIT, ICL_TYPE_STRING,
			   __FILE__, ICL_TYPE_INT32, __LINE__,
			   ICL_TYPE_POINTER, tdc, ICL_TYPE_INT32,
			   tdc->dflags);
		ReleaseReadLock(&tdc->lock);
		ReleaseReadLock(&avc->lock);
		code = afs_osi_SleepSig(&tdc->validPos);
		ObtainReadLock(&avc->lock);
		ObtainReadLock(&tdc->lock);
	    }
	    if (code) {
		error = code;
		break;
	    }
	    /* fetching flag gone, data is here, or we never tried
	     * (BBusy for instance) */
	    len = tdc->validPos - filePos;
	    versionOk = hsame(avc->f.m.DataVersion, tdc->f.versionNo) ? 1 : 0;
	    if (tdc->dflags & DFFetching) {
		/* still fetching, some new data is here:
		 * compute length and offset */
		offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
	    } else {
		/* no longer fetching, verify data version (avoid new
		 * GetDCache call) */
		if (versionOk && len > 0) {
		    offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
		} else {
		    /* don't have current data, so get it below */
		    afs_Trace3(afs_iclSetp, CM_TRACE_VERSIONNO,
			       ICL_TYPE_INT64, ICL_HANDLE_OFFSET(filePos),
			       ICL_TYPE_HYPER, &avc->f.m.DataVersion,
			       ICL_TYPE_HYPER, &tdc->f.versionNo);
#if 0
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
if (afs_protocols & VICEP_ACCESS) {
printf("afs_read: DV mismatch? %d instead of %d for %u.%u.%u\n", tdc->f.versionNo.low, avc->f.m.DataVersion.low, avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
printf("afs_read: validPos %llu filePos %llu totalLength %d m.Length %llu noLock %d\n", tdc->validPos, filePos, totalLength, avc->f.m.Length, noLock);
printf("afs_read: or len too low? %lld for %u.%u.%u\n", len, avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
}
#endif
#endif
		    ReleaseReadLock(&tdc->lock);
		    afs_PutDCache(tdc);
		    tdc = NULL;
		}
	    }

	    if (!tdc) {
#ifdef STRUCT_TASK_STRUCT_HAS_CRED
		if (afs_protocols & VICEP_ACCESS) { /* avoid foreground fetch */
		    if (!versionOk) {
printf("afs_read: avoid forground %u.%u.%u\n", avc->f.fid.Fid.Volume, avc->f.fid.Fid.Vnode, avc->f.fid.Fid.Unique);
			goto try_background;
		    }
		}
#endif
		/* If we get here, it was not possible to start the
		 * background daemon. With flag == 1 afs_GetDCache
		 * does the FetchData rpc synchronously.
		 */
		ReleaseReadLock(&avc->lock);
		tdc = afs_GetDCache(avc, filePos, treq, &offset, &len, 1);
		ObtainReadLock(&avc->lock);
		if (tdc)
		    ObtainReadLock(&tdc->lock);
	    }
	}

	if (!tdc) {
	    error = EIO;
	    break;
	}
	len = tdc->validPos - filePos;
	afs_Trace3(afs_iclSetp, CM_TRACE_VNODEREAD, ICL_TYPE_POINTER, tdc,
		   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(offset),
		   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(len));
	if (len > totalLength)
	    len = totalLength;	/* will read len bytes */
	if (len <= 0) {		/* shouldn't get here if DFFetching is on */
	    afs_Trace4(afs_iclSetp, CM_TRACE_VNODEREAD2, ICL_TYPE_POINTER,
		       tdc, ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(tdc->validPos),
		       ICL_TYPE_INT32, tdc->f.chunkBytes, ICL_TYPE_INT32,
		       tdc->dflags);
	    /* read past the end of a chunk, may not be at next chunk yet, and yet
	     * also not at eof, so may have to supply fake zeros */
	    len = AFS_CHUNKTOSIZE(tdc->f.chunk) - offset;	/* bytes left in chunk addr space */
	    if (len > totalLength)
		len = totalLength;	/* and still within xfr request */
	    tlen = avc->f.m.Length - offset;	/* and still within file */
	    if (len > tlen)
		len = tlen;
	    if (len > AFS_ZEROS)
		len = sizeof(afs_zeros);	/* and in 0 buffer */
#ifdef AFS_DARWIN80_ENV
	    trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
	    afsio_copy(auio, &tuio, tvec);
	    trimlen = len;
	    afsio_trim(&tuio, trimlen);
#endif
	    AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
	    if (code) {
		error = code;
		break;
	    }
	} else {
	    /* get the data from the file */
	    tfile = (struct osi_file *)osi_UFSOpen(&tdc->f.inode);
#ifdef AFS_DARWIN80_ENV
	    trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
	    uio_setoffset(tuiop, offset);
#else
	    /* mung uio structure to be right for this transfer */
	    afsio_copy(auio, &tuio, tvec);
	    trimlen = len;
	    afsio_trim(&tuio, trimlen);
	    tuio.afsio_offset = offset;
#endif

#if defined(AFS_AIX41_ENV)
	    AFS_GUNLOCK();
	    code =
		VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, &tuio, NULL, NULL,
			  NULL, afs_osi_credp);
	    AFS_GLOCK();
#elif defined(AFS_AIX32_ENV)
	    code =
		VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, &tuio, NULL, NULL);
	    /* Flush all JFS pages now for big performance gain in big file cases
	     * If we do something like this, must check to be sure that AFS file
	     * isn't mmapped... see afs_gn_map() for why.
	     */
/*
	  if (tfile->vnode->v_gnode && tfile->vnode->v_gnode->gn_seg) {
 many different ways to do similar things:
   so far, the best performing one is #2, but #1 might match it if we
   straighten out the confusion regarding which pages to flush.  It
   really does matter.
   1.	    vm_flushp(tfile->vnode->v_gnode->gn_seg, 0, len/PAGESIZE - 1);
   2.	    vm_releasep(tfile->vnode->v_gnode->gn_seg, offset/PAGESIZE,
			(len + PAGESIZE-1)/PAGESIZE);
   3.	    vms_inactive(tfile->vnode->v_gnode->gn_seg) Doesn't work correctly
   4.  	    vms_delete(tfile->vnode->v_gnode->gn_seg) probably also fails
	    tfile->vnode->v_gnode->gn_seg = NULL;
   5.       deletep
   6.       ipgrlse
   7.       ifreeseg
          Unfortunately, this seems to cause frequent "cache corruption" episodes.
   	    vm_releasep(tfile->vnode->v_gnode->gn_seg, offset/PAGESIZE,
			(len + PAGESIZE-1)/PAGESIZE);
	  }
*/
#elif defined(AFS_AIX_ENV)
	    code =
		VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, (off_t) & offset,
			  &tuio, NULL, NULL, -1);
#elif defined(AFS_SUN5_ENV)
	    AFS_GUNLOCK();
#ifdef AFS_SUN510_ENV
	    VOP_RWLOCK(tfile->vnode, 0, NULL);
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp, NULL);
	    VOP_RWUNLOCK(tfile->vnode, 0, NULL);
#else
	    VOP_RWLOCK(tfile->vnode, 0);
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
	    VOP_RWUNLOCK(tfile->vnode, 0);
#endif
	    AFS_GLOCK();
#elif defined(AFS_SGI_ENV)
	    AFS_GUNLOCK();
	    AFS_VOP_RWLOCK(tfile->vnode, VRWLOCK_READ);
	    AFS_VOP_READ(tfile->vnode, &tuio, IO_ISLOCKED, afs_osi_credp,
			 code);
	    AFS_VOP_RWUNLOCK(tfile->vnode, VRWLOCK_READ);
	    AFS_GLOCK();
#elif defined(AFS_HPUX100_ENV)
	    AFS_GUNLOCK();
	    code = VOP_RDWR(tfile->vnode, &tuio, UIO_READ, 0, afs_osi_credp);
	    AFS_GLOCK();
#elif defined(AFS_LINUX20_ENV)
	    AFS_GUNLOCK();
	    code = osi_rdwr(tfile, &tuio, UIO_READ);
	    AFS_GLOCK();
#elif defined(AFS_DARWIN80_ENV)
	    AFS_GUNLOCK();
	    code = VNOP_READ(tfile->vnode, tuiop, 0, afs_osi_ctxtp);
	    AFS_GLOCK();
#elif defined(AFS_DARWIN_ENV)
	    AFS_GUNLOCK();
	    VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, current_proc());
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
	    VOP_UNLOCK(tfile->vnode, 0, current_proc());
	    AFS_GLOCK();
#elif defined(AFS_FBSD80_ENV)
	    AFS_GUNLOCK();
	    VOP_LOCK(tfile->vnode, LK_EXCLUSIVE);
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
	    VOP_UNLOCK(tfile->vnode, 0);
	    AFS_GLOCK();
#elif defined(AFS_FBSD_ENV)
	    AFS_GUNLOCK();
	    VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, curthread);
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
	    VOP_UNLOCK(tfile->vnode, 0, curthread);
	    AFS_GLOCK();
#elif defined(AFS_NBSD_ENV)
            AFS_GUNLOCK();
            VOP_LOCK(tfile->vnode, LK_EXCLUSIVE);
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_UNLOCK(tfile->vnode, 0);
            AFS_GLOCK();

#elif defined(AFS_XBSD_ENV)
	    AFS_GUNLOCK();
	    VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, curproc);
	    code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
	    VOP_UNLOCK(tfile->vnode, 0, curproc);
	    AFS_GLOCK();
#else
	    code = VOP_RDWR(tfile->vnode, &tuio, UIO_READ, 0, afs_osi_credp);
#endif
	    osi_UFSClose(tfile);

	    if (code) {
		error = code;
		break;
	    }
	}
	/* otherwise we've read some, fixup length, etc and continue with next seg */
	len = len - AFS_UIO_RESID(tuiop);	/* compute amount really transferred */
	trimlen = len;
	afsio_skip(auio, trimlen);	/* update input uio structure */
	totalLength -= len;
	transferLength += len;
	filePos += len;
	if (len <= 0)
	    break;		/* surprise eof */
#ifdef AFS_DARWIN80_ENV
	if (tuiop) {
	    uio_free(tuiop);
	    tuiop = 0;
	}
#endif
    }

    /* if we make it here with tdc non-zero, then it is the last chunk we
     * dealt with, and we have to release it when we're done.  We hold on
     * to it in case we need to do a prefetch, obviously.
     */
    if (tdc) {
	ReleaseReadLock(&tdc->lock);
#if !defined(AFS_VM_RDWR_ENV)
	/*
         * try to queue prefetch, if needed. If DataVersion is zero there
	 * should not be any more: files with DV 0 never have been stored
	 * on the fileserver, symbolic links and directories never require
	 * more than a single chunk.
	 */
	if (!noLock && !(hiszero(avc->f.m.DataVersion))) {
	    if (!(tdc->mflags & DFNextStarted))
		afs_PrefetchChunk(avc, tdc, acred, treq);
	}
#endif
	afs_PutDCache(tdc);
    }
    if (!noLock)
	ReleaseReadLock(&avc->lock);

#ifdef AFS_DARWIN80_ENV
    if (tuiop)
       uio_free(tuiop);
#else
    osi_FreeSmallSpace(tvec);
#endif
    AFS_DISCON_UNLOCK();
    error = afs_CheckCode(error, treq, 13);
    afs_DestroyReq(treq);
    return error;
}
Beispiel #3
0
int
afs_StoreAllSegments(struct vcache *avc, struct vrequest *areq,
		     int sync)
{
    struct dcache *tdc;
    afs_int32 code = 0;
    afs_int32 index;
    afs_int32 origCBs, foreign = 0;
    int hash;
    afs_hyper_t newDV, oldDV;	/* DV when we start, and finish, respectively */
    struct dcache **dcList;
    unsigned int i, j, minj, moredata, high, off;
    afs_size_t maxStoredLength;	/* highest offset we've written to server. */
    int safety, marineronce = 0;

    AFS_STATCNT(afs_StoreAllSegments);

    hset(oldDV, avc->f.m.DataVersion);
    hset(newDV, avc->f.m.DataVersion);
    hash = DVHash(&avc->f.fid);
    foreign = (avc->f.states & CForeign);
    dcList = osi_AllocLargeSpace(AFS_LRALLOCSIZ);
    afs_Trace2(afs_iclSetp, CM_TRACE_STOREALL, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(avc->f.m.Length));
#if !defined(AFS_AIX32_ENV) && !defined(AFS_SGI65_ENV)
    /* In the aix vm implementation we need to do the vm_writep even
     * on the memcache case since that's we adjust the file's size
     * and finish flushing partial vm pages.
     */
    if ((cacheDiskType != AFS_FCACHE_TYPE_MEM) ||
	(sync & AFS_VMSYNC_INVAL) || (sync & AFS_VMSYNC) ||
	(sync & AFS_LASTSTORE))
#endif /* !AFS_AIX32_ENV && !AFS_SGI65_ENV */
    {
	/* If we're not diskless, reading a file may stress the VM
	 * system enough to cause a pageout, and this vnode would be
	 * locked when the pageout occurs.  We can prevent this problem
	 * by making sure all dirty pages are already flushed.  We don't
	 * do this when diskless because reading a diskless (i.e.
	 * memory-resident) chunk doesn't require using new VM, and we
	 * also don't want to dump more dirty data into a diskless cache,
	 * since they're smaller, and we might exceed its available
	 * space.
	 */
#if	defined(AFS_SUN5_ENV)
	if (sync & AFS_VMSYNC_INVAL)	/* invalidate VM pages */
	    osi_VM_TryToSmush(avc, CRED(), 1);
	else
#endif
	    osi_VM_StoreAllSegments(avc);
    }
    if (AFS_IS_DISCONNECTED && !AFS_IN_SYNC) {
	/* This will probably make someone sad ... */
	/*printf("Net down in afs_StoreSegments\n");*/
	return ENETDOWN;
    }
    ConvertWToSLock(&avc->lock);

    /*
     * Subsequent code expects a sorted list, and it expects all the
     * chunks in the list to be contiguous, so we need a sort and a
     * while loop in here, too - but this will work for a first pass...
     * 92.10.05 - OK, there's a sort in here now.  It's kind of a modified
     *            bin sort, I guess.  Chunk numbers start with 0
     *
     * - Have to get a write lock on xdcache because GetDSlot might need it (if
     *   the chunk doesn't have a dcache struct).
     *   This seems like overkill in most cases.
     * - I'm not sure that it's safe to do "index = .hvNextp", then unlock
     *   xdcache, then relock xdcache and try to use index.  It is done
     *   a lot elsewhere in the CM, but I'm not buying that argument.
     * - should be able to check IFDataMod without doing the GetDSlot (just
     *   hold afs_xdcache).  That way, it's easy to do this without the
     *   writelock on afs_xdcache, and we save unneccessary disk
     *   operations. I don't think that works, 'cuz the next pointers
     *   are still on disk.
     */
    origCBs = afs_allCBs;

    maxStoredLength = 0;
    minj = 0;

    do {
	memset(dcList, 0, NCHUNKSATONCE * sizeof(struct dcache *));
	high = 0;
	moredata = FALSE;

	/* lock and start over from beginning of hash chain
	 * in order to avoid a race condition. */
	ObtainWriteLock(&afs_xdcache, 284);
	index = afs_dvhashTbl[hash];

	for (j = 0; index != NULLIDX;) {
	    if ((afs_indexFlags[index] & IFDataMod)
		&& (afs_indexUnique[index] == avc->f.fid.Fid.Unique)) {
		tdc = afs_GetValidDSlot(index);	/* refcount+1. */
		if (!tdc) {
		    ReleaseWriteLock(&afs_xdcache);
		    code = EIO;
		    goto done;
		}
		ReleaseReadLock(&tdc->tlock);
		if (!FidCmp(&tdc->f.fid, &avc->f.fid) && tdc->f.chunk >= minj) {
		    off = tdc->f.chunk - minj;
		    if (off < NCHUNKSATONCE) {
			if (dcList[off])
			    osi_Panic("dclist slot already in use!");
			if (afs_mariner && !marineronce) {
			    /* first chunk only */
			    afs_MarinerLog("store$Storing", avc);
			    marineronce++;
			}
			dcList[off] = tdc;
			if (off > high)
			    high = off;
			j++;
			/* DCLOCKXXX: chunkBytes is protected by tdc->lock which we
			 * can't grab here, due to lock ordering with afs_xdcache.
			 * So, disable this shortcut for now.  -- kolya 2001-10-13
			 */
			/* shortcut: big win for little files */
			/* tlen -= tdc->f.chunkBytes;
			 * if (tlen <= 0)
			 *    break;
			 */
		    } else {
			moredata = TRUE;
			afs_PutDCache(tdc);
			if (j == NCHUNKSATONCE)
			    break;
		    }
		} else {
		    afs_PutDCache(tdc);
		}
	    }
	    index = afs_dvnextTbl[index];
	}
	ReleaseWriteLock(&afs_xdcache);

	/* this guy writes chunks, puts back dcache structs, and bumps newDV */
	/* "moredata" just says "there are more dirty chunks yet to come".
	 */
	if (j) {
	    code =
		afs_CacheStoreVCache(dcList, avc, areq, sync,
				   minj, high, moredata,
				   &newDV, &maxStoredLength);
	    /* Release any zero-length dcache entries in our interval
	     * that we locked but didn't store back above.
	     */
	    for (j = 0; j <= high; j++) {
		tdc = dcList[j];
		if (tdc) {
		    osi_Assert(tdc->f.chunkBytes == 0);
		    ReleaseSharedLock(&tdc->lock);
		    afs_PutDCache(tdc);
		}
	    }
	}
	/* if (j) */
	minj += NCHUNKSATONCE;
    } while (!code && moredata);

 done:
    UpgradeSToWLock(&avc->lock, 29);

    /* send a trivial truncation store if did nothing else */
    if (code == 0) {
	/*
	 * Call StoreMini if we haven't written enough data to extend the
	 * file at the fileserver to the client's notion of the file length.
	 */
	if ((avc->f.truncPos != AFS_NOTRUNC)
	    || ((avc->f.states & CExtendedFile)
		&& (maxStoredLength < avc->f.m.Length))) {
	    code = afs_StoreMini(avc, areq);
	    if (code == 0)
		hadd32(newDV, 1);	/* just bumped here, too */
	}
	avc->f.states &= ~CExtendedFile;
    }

    /*
     * Finally, turn off DWriting, turn on DFEntryMod,
     * update f.versionNo.
     * A lot of this could be integrated into the loop above
     */
    if (!code) {
	afs_hyper_t h_unset;
	hones(h_unset);

	minj = 0;

	do {
	    moredata = FALSE;
	    memset(dcList, 0,
		   NCHUNKSATONCE * sizeof(struct dcache *));

	    /* overkill, but it gets the lock in case GetDSlot needs it */
	    ObtainWriteLock(&afs_xdcache, 285);

	    for (j = 0, safety = 0, index = afs_dvhashTbl[hash];
		 index != NULLIDX && safety < afs_cacheFiles + 2;
	         index = afs_dvnextTbl[index]) {

		if (afs_indexUnique[index] == avc->f.fid.Fid.Unique) {
		    tdc = afs_GetValidDSlot(index);
		    if (!tdc) {
			/* This is okay; since manipulating the dcaches at this
			 * point is best-effort. We only get a dcache here to
			 * increment the dv and turn off DWriting. If we were
			 * supposed to do that for a dcache, but could not
			 * due to an I/O error, it just means the dv won't
			 * be updated so we don't be able to use that cached
			 * chunk in the future. That's inefficient, but not
			 * an error. */
			continue;
		    }
		    ReleaseReadLock(&tdc->tlock);

		    if (!FidCmp(&tdc->f.fid, &avc->f.fid)
			&& tdc->f.chunk >= minj) {
			off = tdc->f.chunk - minj;
			if (off < NCHUNKSATONCE) {
			    /* this is the file, and the correct chunk range */
			    if (j >= NCHUNKSATONCE)
				osi_Panic
				    ("Too many dcache entries in range\n");
			    dcList[j++] = tdc;
			} else {
			    moredata = TRUE;
			    afs_PutDCache(tdc);
			    if (j == NCHUNKSATONCE)
				break;
			}
		    } else {
			afs_PutDCache(tdc);
		    }
		}
	    }
	    ReleaseWriteLock(&afs_xdcache);

	    for (i = 0; i < j; i++) {
		/* Iterate over the dcache entries we collected above */
		tdc = dcList[i];
		ObtainSharedLock(&tdc->lock, 677);

		/* was code here to clear IFDataMod, but it should only be done
		 * in storedcache and storealldcache.
		 */
		/* Only increase DV if we had up-to-date data to start with.
		 * Otherwise, we could be falsely upgrading an old chunk
		 * (that we never read) into one labelled with the current
		 * DV #.  Also note that we check that no intervening stores
		 * occurred, otherwise we might mislabel cache information
		 * for a chunk that we didn't store this time
		 */
		/* Don't update the version number if it's not yet set. */
		if (!hsame(tdc->f.versionNo, h_unset)
		    && hcmp(tdc->f.versionNo, oldDV) >= 0) {

		    if ((!(afs_dvhack || foreign)
			 && hsame(avc->f.m.DataVersion, newDV))
			|| ((afs_dvhack || foreign)
			    && (origCBs == afs_allCBs))) {
			/* no error, this is the DV */

			UpgradeSToWLock(&tdc->lock, 678);
			hset(tdc->f.versionNo, avc->f.m.DataVersion);
			tdc->dflags |= DFEntryMod;
			/* DWriting may not have gotten cleared above, if all
			 * we did was a StoreMini */
			tdc->f.states &= ~DWriting;
			ConvertWToSLock(&tdc->lock);
		    }
		}

		ReleaseSharedLock(&tdc->lock);
		afs_PutDCache(tdc);
	    }

	    minj += NCHUNKSATONCE;

	} while (moredata);
    }

    if (code) {
	/*
	 * Invalidate chunks after an error for ccores files since
	 * afs_inactive won't be called for these and they won't be
	 * invalidated. Also discard data if it's a permanent error from the
	 * fileserver.
	 */
	if (areq->permWriteError || (avc->f.states & CCore)) {
	    afs_InvalidateAllSegments(avc);
	}
    }
    afs_Trace3(afs_iclSetp, CM_TRACE_STOREALLDONE, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_INT32, avc->f.m.Length, ICL_TYPE_INT32, code);
    /* would like a Trace5, but it doesn't exist... */
    afs_Trace3(afs_iclSetp, CM_TRACE_AVCLOCKER, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_INT32, avc->lock.wait_states, ICL_TYPE_INT32,
	       avc->lock.excl_locked);
    afs_Trace4(afs_iclSetp, CM_TRACE_AVCLOCKEE, ICL_TYPE_POINTER, avc,
	       ICL_TYPE_INT32, avc->lock.wait_states, ICL_TYPE_INT32,
	       avc->lock.readers_reading, ICL_TYPE_INT32,
	       avc->lock.num_waiting);

    /*
     * Finally, if updated DataVersion matches newDV, we did all of the
     * stores.  If mapDV indicates that the page cache was flushed up
     * to when we started the store, then we can relabel them as flushed
     * as recently as newDV.
     * Turn off CDirty bit because the stored data is now in sync with server.
     */
    if (code == 0 && hcmp(avc->mapDV, oldDV) >= 0) {
	if ((!(afs_dvhack || foreign) && hsame(avc->f.m.DataVersion, newDV))
	    || ((afs_dvhack || foreign) && (origCBs == afs_allCBs))) {
	    hset(avc->mapDV, newDV);
	    avc->f.states &= ~CDirty;
	}
    }
    osi_FreeLargeSpace(dcList);

    /* If not the final write a temporary error is ok. */
    if (code && !areq->permWriteError && !(sync & AFS_LASTSTORE))
	code = 0;

    return code;

}				/*afs_StoreAllSegments (new 03/02/94) */
int
afsrename(struct vcache *aodp, char *aname1, struct vcache *andp,
	  char *aname2, struct AFS_UCRED *acred, struct vrequest *areq)
{
    register struct afs_conn *tc;
    register afs_int32 code = 0;
    afs_int32 returnCode;
    int oneDir, doLocally;
    afs_size_t offset, len;
    struct VenusFid unlinkFid, fileFid;
    struct vcache *tvc;
    struct dcache *tdc1, *tdc2;
    struct AFSFetchStatus OutOldDirStatus, OutNewDirStatus;
    struct AFSVolSync tsync;
    XSTATS_DECLS;
    AFS_STATCNT(afs_rename);
    afs_Trace4(afs_iclSetp, CM_TRACE_RENAME, ICL_TYPE_POINTER, aodp,
	       ICL_TYPE_STRING, aname1, ICL_TYPE_POINTER, andp,
	       ICL_TYPE_STRING, aname2);

    if (strlen(aname1) > AFSNAMEMAX || strlen(aname2) > AFSNAMEMAX) {
	code = ENAMETOOLONG;
	goto done;
    }

    /* verify the latest versions of the stat cache entries */
  tagain:
    code = afs_VerifyVCache(aodp, areq);
    if (code)
	goto done;
    code = afs_VerifyVCache(andp, areq);
    if (code)
	goto done;

    /* lock in appropriate order, after some checks */
    if (aodp->f.fid.Cell != andp->f.fid.Cell
	|| aodp->f.fid.Fid.Volume != andp->f.fid.Fid.Volume) {
	code = EXDEV;
	goto done;
    }
    oneDir = 0;
    code = 0;
    if (andp->f.fid.Fid.Vnode == aodp->f.fid.Fid.Vnode) {
	if (!strcmp(aname1, aname2)) {
	    /* Same directory and same name; this is a noop and just return success
	     * to save cycles and follow posix standards */

	    code = 0;
	    goto done;
	}
	
	if (AFS_IS_DISCONNECTED && !AFS_IS_DISCON_RW) {
	    code = ENETDOWN;
	    goto done;
	}
	
	ObtainWriteLock(&andp->lock, 147);
	tdc1 = afs_GetDCache(aodp, (afs_size_t) 0, areq, &offset, &len, 0);
	if (!tdc1) {
	    code = ENOENT;
	} else {
	    ObtainWriteLock(&tdc1->lock, 643);
	}
	tdc2 = tdc1;
	oneDir = 1;		/* only one dude locked */
    } else if ((andp->f.states & CRO) || (aodp->f.states & CRO)) {
	code = EROFS;
	goto done;
    } else if (andp->f.fid.Fid.Vnode < aodp->f.fid.Fid.Vnode) {
	ObtainWriteLock(&andp->lock, 148);	/* lock smaller one first */
	ObtainWriteLock(&aodp->lock, 149);
	tdc2 = afs_FindDCache(andp, (afs_size_t) 0);
	if (tdc2)
	    ObtainWriteLock(&tdc2->lock, 644);
	tdc1 = afs_GetDCache(aodp, (afs_size_t) 0, areq, &offset, &len, 0);
	if (tdc1)
	    ObtainWriteLock(&tdc1->lock, 645);
	else
	    code = ENOENT;
    } else {
	ObtainWriteLock(&aodp->lock, 150);	/* lock smaller one first */
	ObtainWriteLock(&andp->lock, 557);
	tdc1 = afs_GetDCache(aodp, (afs_size_t) 0, areq, &offset, &len, 0);
	if (tdc1)
	    ObtainWriteLock(&tdc1->lock, 646);
	else
	    code = ENOENT;
	tdc2 = afs_FindDCache(andp, (afs_size_t) 0);
	if (tdc2)
	    ObtainWriteLock(&tdc2->lock, 647);
    }

    osi_dnlc_remove(aodp, aname1, 0);
    osi_dnlc_remove(andp, aname2, 0);

    /*
     * Make sure that the data in the cache is current. We may have
     * received a callback while we were waiting for the write lock.
     */
    if (tdc1) {
	if (!(aodp->f.states & CStatd)
	    || !hsame(aodp->f.m.DataVersion, tdc1->f.versionNo)) {

	    ReleaseWriteLock(&aodp->lock);
	    if (!oneDir) {
		if (tdc2) {
		    ReleaseWriteLock(&tdc2->lock);
		    afs_PutDCache(tdc2);
		}
		ReleaseWriteLock(&andp->lock);
	    }
	    ReleaseWriteLock(&tdc1->lock);
	    afs_PutDCache(tdc1);
	    goto tagain;
	}
    }

    if (code == 0)
	code = afs_dir_Lookup(tdc1, aname1, &fileFid.Fid);
    if (code) {
	if (tdc1) {
	    ReleaseWriteLock(&tdc1->lock);
	    afs_PutDCache(tdc1);
	}
	ReleaseWriteLock(&aodp->lock);
	if (!oneDir) {
	    if (tdc2) {
		ReleaseWriteLock(&tdc2->lock);
		afs_PutDCache(tdc2);
	    }
	    ReleaseWriteLock(&andp->lock);
	}
	goto done;
    }

    if (!AFS_IS_DISCON_RW) {
    	/* Connected. */
	do {
	    tc = afs_Conn(&aodp->f.fid, areq, SHARED_LOCK);
	    if (tc) {
	    	XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_RENAME);
	    	RX_AFS_GUNLOCK();
	    	code =
		    RXAFS_Rename(tc->id,
		    			(struct AFSFid *)&aodp->f.fid.Fid,
					aname1,
					(struct AFSFid *)&andp->f.fid.Fid,
					aname2,
					&OutOldDirStatus,
					&OutNewDirStatus,
					&tsync);
	        RX_AFS_GLOCK();
	        XSTATS_END_TIME;
	    } else
	    	code = -1;

	} while (afs_Analyze
	     (tc, code, &andp->f.fid, areq, AFS_STATS_FS_RPCIDX_RENAME,
	      SHARED_LOCK, NULL));

    } else {
#if defined(AFS_DISCON_ENV)
	/* Disconnected. */

	/* Seek moved file vcache. */
	fileFid.Cell = aodp->f.fid.Cell;
	fileFid.Fid.Volume = aodp->f.fid.Fid.Volume;
	ObtainSharedLock(&afs_xvcache, 754);
	tvc = afs_FindVCache(&fileFid, 0 , 1);
	ReleaseSharedLock(&afs_xvcache);

	if (tvc) {
	    /* XXX - We're locking this vcache whilst holding dcaches. Ooops */
	    ObtainWriteLock(&tvc->lock, 750);
	    if (!(tvc->f.ddirty_flags & (VDisconRename|VDisconCreate))) {
		/* If the vnode was created locally, then we don't care
		 * about recording the rename - we'll do it automatically
		 * on replay. If we've already renamed, we've already stored
		 * the required information about where we came from.
		 */
		
		if (!aodp->f.shadow.vnode) {
	    	    /* Make shadow copy of parent dir only. */
    	    	    afs_MakeShadowDir(aodp, tdc1);
	        }

		/* Save old parent dir fid so it will be searchable
	     	 * in the shadow dir.
	     	 */
    	    	tvc->f.oldParent.vnode = aodp->f.fid.Fid.Vnode;
	    	tvc->f.oldParent.unique = aodp->f.fid.Fid.Unique;

		afs_DisconAddDirty(tvc, 
				   VDisconRename 
				     | (oneDir ? VDisconRenameSameDir:0), 
				   1);
	    }

	    ReleaseWriteLock(&tvc->lock);
	    afs_PutVCache(tvc);
	} else {
	    code = ENOENT;
	}			/* if (tvc) */
#endif
    }				/* if !(AFS_IS_DISCON_RW)*/
    returnCode = code;		/* remember for later */

    /* Now we try to do things locally.  This is really loathsome code. */
    unlinkFid.Fid.Vnode = 0;
    if (code == 0) {
	/*  In any event, we don't really care if the data (tdc2) is not
	 * in the cache; if it isn't, we won't do the update locally.  */
	/* see if version numbers increased properly */
	doLocally = 1;
	if (!AFS_IS_DISCON_RW) {
	    if (oneDir) {
	    	/* number increases by 1 for whole rename operation */
	    	if (!afs_LocalHero(aodp, tdc1, &OutOldDirStatus, 1)) {
		    doLocally = 0;
	    	}
	    } else {
	    	/* two separate dirs, each increasing by 1 */
	    	if (!afs_LocalHero(aodp, tdc1, &OutOldDirStatus, 1))
		    doLocally = 0;
	    	if (!afs_LocalHero(andp, tdc2, &OutNewDirStatus, 1))
		    doLocally = 0;
	    	if (!doLocally) {
		    if (tdc1) {
		    	ZapDCE(tdc1);
		    	DZap(tdc1);
		    }
		    if (tdc2) {
		    	ZapDCE(tdc2);
		    	DZap(tdc2);
		    }
	        }
	    }
	}			/* if (!AFS_IS_DISCON_RW) */

	/* now really do the work */
	if (doLocally) {
	    /* first lookup the fid of the dude we're moving */
	    code = afs_dir_Lookup(tdc1, aname1, &fileFid.Fid);
	    if (code == 0) {
		/* delete the source */
		code = afs_dir_Delete(tdc1, aname1);
	    }
	    /* first see if target is there */
	    if (code == 0
		&& afs_dir_Lookup(tdc2, aname2,
				  &unlinkFid.Fid) == 0) {
		/* target already exists, and will be unlinked by server */
		code = afs_dir_Delete(tdc2, aname2);
	    }
	    if (code == 0) {
		ObtainWriteLock(&afs_xdcache, 292);
		code = afs_dir_Create(tdc2, aname2, &fileFid.Fid);
		ReleaseWriteLock(&afs_xdcache);
	    }
	    if (code != 0) {
		ZapDCE(tdc1);
		DZap(tdc1);
		if (!oneDir) {
		    ZapDCE(tdc2);
		    DZap(tdc2);
		}
	    }
	}


	/* update dir link counts */
	if (AFS_IS_DISCON_RW) {
	    if (!oneDir) {
		aodp->f.m.LinkCount--;
		andp->f.m.LinkCount++;
	    }
	    /* If we're in the same directory, link count doesn't change */
	} else {
	    aodp->f.m.LinkCount = OutOldDirStatus.LinkCount;
	    if (!oneDir)
		andp->f.m.LinkCount = OutNewDirStatus.LinkCount;
	}

    } else {			/* operation failed (code != 0) */
	if (code < 0) {
	    /* if failed, server might have done something anyway, and 
	     * assume that we know about it */
	    ObtainWriteLock(&afs_xcbhash, 498);
	    afs_DequeueCallback(aodp);
	    afs_DequeueCallback(andp);
	    andp->f.states &= ~CStatd;
	    aodp->f.states &= ~CStatd;
	    ReleaseWriteLock(&afs_xcbhash);
	    osi_dnlc_purgedp(andp);
	    osi_dnlc_purgedp(aodp);
	}
    }

    /* release locks */
    if (tdc1) {
	ReleaseWriteLock(&tdc1->lock);
	afs_PutDCache(tdc1);
    }

    if ((!oneDir) && tdc2) {
	ReleaseWriteLock(&tdc2->lock);
	afs_PutDCache(tdc2);
    }

    ReleaseWriteLock(&aodp->lock);

    if (!oneDir) {
	ReleaseWriteLock(&andp->lock);
    }

    if (returnCode) {
	code = returnCode;
	goto done;
    }

    /* now, some more details.  if unlinkFid.Fid.Vnode then we should decrement
     * the link count on this file.  Note that if fileFid is a dir, then we don't
     * have to invalidate its ".." entry, since its DataVersion # should have
     * changed. However, interface is not good enough to tell us the
     * *file*'s new DataVersion, so we're stuck.  Our hack: delete mark
     * the data as having an "unknown" version (effectively discarding the ".."
     * entry */
    if (unlinkFid.Fid.Vnode) {

	unlinkFid.Fid.Volume = aodp->f.fid.Fid.Volume;
	unlinkFid.Cell = aodp->f.fid.Cell;
	tvc = NULL;
	if (!unlinkFid.Fid.Unique) {
	    tvc = afs_LookupVCache(&unlinkFid, areq, NULL, aodp, aname1);
	}
	if (!tvc)		/* lookup failed or wasn't called */
	    tvc = afs_GetVCache(&unlinkFid, areq, NULL, NULL);

	if (tvc) {
#ifdef AFS_BOZONLOCK_ENV
	    afs_BozonLock(&tvc->pvnLock, tvc);	/* Since afs_TryToSmush will do a pvn_vptrunc */
#endif
	    ObtainWriteLock(&tvc->lock, 151);
	    tvc->f.m.LinkCount--;
	    tvc->f.states &= ~CUnique;	/* For the dfs xlator */
	    if (tvc->f.m.LinkCount == 0 && !osi_Active(tvc)) {
		/* if this was last guy (probably) discard from cache.
		 * We have to be careful to not get rid of the stat
		 * information, since otherwise operations will start
		 * failing even if the file was still open (or
		 * otherwise active), and the server no longer has the
		 * info.  If the file still has valid links, we'll get
		 * a break-callback msg from the server, so it doesn't
		 * matter that we don't discard the status info */
		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);
	}
    }

    /* now handle ".." invalidation */
    if (!oneDir) {
	fileFid.Fid.Volume = aodp->f.fid.Fid.Volume;
	fileFid.Cell = aodp->f.fid.Cell;
	if (!fileFid.Fid.Unique)
	    tvc = afs_LookupVCache(&fileFid, areq, NULL, andp, aname2);
	else
	    tvc = afs_GetVCache(&fileFid, areq, NULL, (struct vcache *)0);
	if (tvc && (vType(tvc) == VDIR)) {
	    ObtainWriteLock(&tvc->lock, 152);
	    tdc1 = afs_FindDCache(tvc, (afs_size_t) 0);
	    if (tdc1) {
		if (AFS_IS_DISCON_RW) {
#if defined(AFS_DISCON_ENV)
		    /* If disconnected, we need to fix (not discard) the "..".*/
		    afs_dir_ChangeFid(tdc1,
		    	"..",
		    	&aodp->f.fid.Fid.Vnode,
			&andp->f.fid.Fid.Vnode);
#endif
		} else {
		    ObtainWriteLock(&tdc1->lock, 648);
		    ZapDCE(tdc1);	/* mark as unknown */
		    DZap(tdc1);
		    ReleaseWriteLock(&tdc1->lock);
		    afs_PutDCache(tdc1);	/* put it back */
		}
	    }
	    osi_dnlc_remove(tvc, "..", 0);
	    ReleaseWriteLock(&tvc->lock);
	    afs_PutVCache(tvc);
	} else if (AFS_IS_DISCON_RW && tvc && (vType(tvc) == VREG)) {
	    /* XXX - Should tvc not get locked here? */
	    tvc->f.parent.vnode = andp->f.fid.Fid.Vnode;
	    tvc->f.parent.unique = andp->f.fid.Fid.Unique;
	} else if (tvc) {
	    /* True we shouldn't come here since tvc SHOULD be a dir, but we
	     * 'syntactically' need to unless  we change the 'if' above...
	     */
	    afs_PutVCache(tvc);
	}
    }
    code = returnCode;
  done:
    return code;
}
Beispiel #5
0
/*------------------------------------------------------------------------
 * EXPORTED afs_Analyze
 *
 * Description:
 *	Analyze the outcome of an RPC operation, taking whatever support
 *	actions are necessary.
 *
 * Arguments:
 *	aconn : Ptr to the relevant connection on which the call was made.
 *	acode : The return code experienced by the RPC.
 *	afid  : The FID of the file involved in the action.  This argument
 *		may be null if none was involved.
 *	areq  : The request record associated with this operation.
 *      op    : which RPC we are analyzing.
 *      cellp : pointer to a cell struct.  Must provide either fid or cell.
 *
 * Returns:
 *	Non-zero value if the related RPC operation should be retried,
 *	zero otherwise.
 *
 * Environment:
 *	This routine is typically called in a do-while loop, causing the
 *	embedded RPC operation to be called repeatedly if appropriate
 *	until whatever error condition (if any) is intolerable.
 *
 * Side Effects:
 *	As advertised.
 *
 * NOTE:
 *	The retry return value is used by afs_StoreAllSegments to determine
 *	if this is a temporary or permanent error.
 *------------------------------------------------------------------------*/
int
afs_Analyze(register struct afs_conn *aconn, afs_int32 acode,
	    struct VenusFid *afid, register struct vrequest *areq, int op,
	    afs_int32 locktype, struct cell *cellp)
{
    afs_int32 i;
    struct srvAddr *sa;
    struct server *tsp;
    struct volume *tvp;
    afs_int32 shouldRetry = 0;
    afs_int32 serversleft = 1;
    struct afs_stats_RPCErrors *aerrP;
    afs_int32 markeddown;

 
 
    if (AFS_IS_DISCONNECTED && !AFS_IN_SYNC) {
	/* On reconnection, act as connected. XXX: for now.... */
        /* SXW - This may get very tired after a while. We should try and
	 *       intercept all RPCs before they get here ... */
	/*printf("afs_Analyze: disconnected\n");*/
	afs_FinalizeReq(areq);
	if (aconn) {
	    /* SXW - I suspect that this will _never_ happen - we shouldn't
	     *       get a connection because we're disconnected !!!*/
	    afs_PutConn(aconn, locktype);
	}
	return 0;
    }
    
    AFS_STATCNT(afs_Analyze);
    afs_Trace4(afs_iclSetp, CM_TRACE_ANALYZE, ICL_TYPE_INT32, op,
	       ICL_TYPE_POINTER, aconn, ICL_TYPE_INT32, acode, ICL_TYPE_LONG,
	       areq->uid);

    aerrP = (struct afs_stats_RPCErrors *)0;

    if ((op >= 0) && (op < AFS_STATS_NUM_FS_RPC_OPS))
	aerrP = &(afs_stats_cmfullperf.rpc.fsRPCErrors[op]);

    afs_FinalizeReq(areq);
    if (!aconn && areq->busyCount) {	/* one RPC or more got VBUSY/VRESTARTING */

	tvp = afs_FindVolume(afid, READ_LOCK);
	if (tvp) {
	    afs_warnuser("afs: Waiting for busy volume %u (%s) in cell %s\n",
			 (afid ? afid->Fid.Volume : 0),
			 (tvp->name ? tvp->name : ""),
			 ((tvp->serverHost[0]
			   && tvp->serverHost[0]->cell) ? tvp->serverHost[0]->
			  cell->cellName : ""));

	    for (i = 0; i < MAXHOSTS; i++) {
		if (tvp->status[i] != not_busy && tvp->status[i] != offline) {
		    tvp->status[i] = not_busy;
		}
		if (tvp->status[i] == not_busy)
		    shouldRetry = 1;
	    }
	    afs_PutVolume(tvp, READ_LOCK);
	} else {
	    afs_warnuser("afs: Waiting for busy volume %u\n",
			 (afid ? afid->Fid.Volume : 0));
	}

	if (areq->busyCount > 100) {
	    if (aerrP)
		(aerrP->err_Volume)++;
	    areq->volumeError = VOLBUSY;
	    shouldRetry = 0;
	} else {
	    VSleep(afs_BusyWaitPeriod);	/* poll periodically */
	}
	if (shouldRetry != 0)
	    areq->busyCount++;

	return shouldRetry;	/* should retry */
    }

    if (!aconn || !aconn->srvr) {
	if (!areq->volumeError) {
	    if (aerrP)
		(aerrP->err_Network)++;
	    if (hm_retry_int && !(areq->flags & O_NONBLOCK) &&	/* "hard" mount */
		((afid && afs_IsPrimaryCellNum(afid->Cell))
		 || (cellp && afs_IsPrimaryCell(cellp)))) {
		if (!afid) {
		    afs_warnuser
			("afs: hard-mount waiting for a vlserver to return to service\n");
		    VSleep(hm_retry_int);
		    afs_CheckServers(1, cellp);
		    shouldRetry = 1;
		} else {
		    tvp = afs_FindVolume(afid, READ_LOCK);
		    if (!tvp || (tvp->states & VRO)) {
			shouldRetry = hm_retry_RO;
		    } else {
			shouldRetry = hm_retry_RW;
		    }
		    if (tvp)
			afs_PutVolume(tvp, READ_LOCK);
		    if (shouldRetry) {
			afs_warnuser
			    ("afs: hard-mount waiting for volume %u\n",
			     afid->Fid.Volume);
			VSleep(hm_retry_int);
			afs_CheckServers(1, cellp);
		    }
		}
	    } /* if (hm_retry_int ... */
	    else {
		areq->networkError = 1;
	    }
	}
	return shouldRetry;
    }

    /* Find server associated with this connection. */
    sa = aconn->srvr;
    tsp = sa->server;

    /* Before we do anything with acode, make sure we translate it back to
     * a system error */
    if ((acode & ~0xff) == ERROR_TABLE_BASE_uae)
	acode = et_to_sys_error(acode);

    if (acode == 0) {
	/* If we previously took an error, mark this volume not busy */
	if (areq->volumeError) {
	    tvp = afs_FindVolume(afid, READ_LOCK);
	    if (tvp) {
		for (i = 0; i < MAXHOSTS; i++) {
		    if (tvp->serverHost[i] == tsp) {
			tvp->status[i] = not_busy;
		    }
		}
		afs_PutVolume(tvp, READ_LOCK);
	    }
	}

	afs_PutConn(aconn, locktype);
	return 0;
    }

    /* If network troubles, mark server as having bogued out again. */
    /* VRESTARTING is < 0 because of backward compatibility issues 
     * with 3.4 file servers and older cache managers */
#ifdef AFS_64BIT_CLIENT
    if (acode == -455)
	acode = 455;
#endif /* AFS_64BIT_CLIENT */
    if ((acode < 0) && (acode != VRESTARTING)) {
	if (acode == RX_CALL_TIMEOUT) {
	    serversleft = afs_BlackListOnce(areq, afid, tsp);
	    areq->idleError++;
	    if (serversleft) {
		shouldRetry = 1;
	    } else {
		shouldRetry = 0;
	    }
	    /* By doing this, we avoid ever marking a server down
	     * in an idle timeout case. That's because the server is 
	     * still responding and may only be letting a single vnode
	     * time out. We otherwise risk having the server continually
	     * be marked down, then up, then down again... 
	     */
	    goto out;
	} 
	markeddown = afs_ServerDown(sa);
	ForceNewConnections(sa); /**multi homed clients lock:afs_xsrvAddr? */
	if (aerrP)
	    (aerrP->err_Server)++;
#if 0
	/* retry *once* when the server is timed out in case of NAT */
	if (markeddown && acode == RX_CALL_DEAD) {
	    aconn->forceConnectFS = 1;
	    shouldRetry = 1;
	}
#endif
    }

    if (acode == VBUSY || acode == VRESTARTING) {
	if (acode == VBUSY) {
	    areq->busyCount++;
	    if (aerrP)
		(aerrP->err_VolumeBusies)++;
	} else
	    areq->busyCount = 1;

	tvp = afs_FindVolume(afid, READ_LOCK);
	if (tvp) {
	    for (i = 0; i < MAXHOSTS; i++) {
		if (tvp->serverHost[i] == tsp) {
		    tvp->status[i] = rdwr_busy;	/* can't tell which yet */
		    /* to tell which, have to look at the op code. */
		}
	    }
	    afs_PutVolume(tvp, READ_LOCK);
	} else {
	    afs_warnuser("afs: Waiting for busy volume %u in cell %s\n",
			 (afid ? afid->Fid.Volume : 0), tsp->cell->cellName);
	    VSleep(afs_BusyWaitPeriod);	/* poll periodically */
	}
	shouldRetry = 1;
	acode = 0;
    } else if (acode == VICETOKENDEAD
	       || (acode & ~0xff) == ERROR_TABLE_BASE_RXK) {
	/* any rxkad error is treated as token expiration */
	struct unixuser *tu;
	/*
	 * I'm calling these errors protection errors, since they involve
	 * faulty authentication.
	 */
	if (aerrP)
	    (aerrP->err_Protection)++;

	tu = afs_FindUser(areq->uid, tsp->cell->cellNum, READ_LOCK);
	if (tu) {
	    if (acode == VICETOKENDEAD) {
		aconn->forceConnectFS = 1;
	    } else if (acode == RXKADEXPIRED) {
		aconn->forceConnectFS = 0;	/* don't check until new tokens set */
		aconn->user->states |= UTokensBad;
		afs_warnuser
		    ("afs: Tokens for user of AFS id %d for cell %s have expired\n",
		     tu->vid, aconn->srvr->server->cell->cellName);
	    } else {
		serversleft = afs_BlackListOnce(areq, afid, tsp);
		areq->tokenError++;

		if (serversleft) {
		    afs_warnuser
			("afs: Tokens for user of AFS id %d for cell %s: rxkad error=%d\n",
			 tu->vid, aconn->srvr->server->cell->cellName, acode);
		    shouldRetry = 1;
		} else {
		    areq->tokenError = 0;
		    aconn->forceConnectFS = 0;	/* don't check until new tokens set */
		    aconn->user->states |= UTokensBad;
		    afs_warnuser
			("afs: Tokens for user of AFS id %d for cell %s are discarded (rxkad error=%d)\n",
			 tu->vid, aconn->srvr->server->cell->cellName, acode);
		}
	    }
	    afs_PutUser(tu, READ_LOCK);
	} else {
	    /* The else case shouldn't be possible and should probably be replaced by a panic? */
	    if (acode == VICETOKENDEAD) {
		aconn->forceConnectFS = 1;
	    } else if (acode == RXKADEXPIRED) {
		aconn->forceConnectFS = 0;	/* don't check until new tokens set */
		aconn->user->states |= UTokensBad;
		afs_warnuser
		    ("afs: Tokens for user %d for cell %s have expired\n",
		     areq->uid, aconn->srvr->server->cell->cellName);
	    } else {
		aconn->forceConnectFS = 0;	/* don't check until new tokens set */
		aconn->user->states |= UTokensBad;
		afs_warnuser
		    ("afs: Tokens for user %d for cell %s are discarded (rxkad error = %d)\n",
		     areq->uid, aconn->srvr->server->cell->cellName, acode);
	    }
	}
	shouldRetry = 1;	/* Try again (as root). */
    }
    /* Check for access violation. */
    else if (acode == EACCES) {
	/* should mark access error in non-existent per-user global structure */
	if (aerrP)
	    (aerrP->err_Protection)++;
	areq->accessError = 1;
	if (op == AFS_STATS_FS_RPCIDX_STOREDATA)
	    areq->permWriteError = 1;
	shouldRetry = 0;
    }
    /* check for ubik errors; treat them like crashed servers */
    else if (acode >= ERROR_TABLE_BASE_U && acode < ERROR_TABLE_BASE_U + 255) {
	afs_ServerDown(sa);
	if (aerrP)
	    (aerrP->err_Server)++;
	shouldRetry = 1;	/* retryable (maybe one is working) */
	VSleep(1);		/* just in case */
    }
    /* Check for bad volume data base / missing volume. */
    else if (acode == VSALVAGE || acode == VOFFLINE || acode == VNOVOL
	     || acode == VNOSERVICE || acode == VMOVED) {
	struct cell *tcell;
	int same;

	shouldRetry = 1;
	areq->volumeError = VOLMISSING;
	if (aerrP)
	    (aerrP->err_Volume)++;
	if (afid && (tcell = afs_GetCell(afid->Cell, 0))) {
	    same = VLDB_Same(afid, areq);
	    tvp = afs_FindVolume(afid, READ_LOCK);
	    if (tvp) {
		for (i = 0; i < MAXHOSTS && tvp->serverHost[i]; i++) {
		    if (tvp->serverHost[i] == tsp) {
			if (tvp->status[i] == end_not_busy)
			    tvp->status[i] = offline;
			else
			    tvp->status[i]++;
		    } else if (!same) {
			tvp->status[i] = not_busy;	/* reset the others */
		    }
		}
		afs_PutVolume(tvp, READ_LOCK);
	    }
	}
    } else if (acode >= ERROR_TABLE_BASE_VL && acode <= ERROR_TABLE_BASE_VL + 255) {	/* vlserver errors */
	shouldRetry = 0;
	areq->volumeError = VOLMISSING;
    } else if (acode >= 0) {
	if (aerrP)
	    (aerrP->err_Other)++;
	if (op == AFS_STATS_FS_RPCIDX_STOREDATA)
	    areq->permWriteError = 1;
	shouldRetry = 0;	/* Other random Vice error. */
    } else if (acode == RX_MSGSIZE) {	/* same meaning as EMSGSIZE... */
	VSleep(1);		/* Just a hack for desperate times. */
	if (aerrP)
	    (aerrP->err_Other)++;
	shouldRetry = 1;	/* packet was too big, please retry call */
    }

    if (acode < 0 && acode != RX_MSGSIZE && acode != VRESTARTING) {
	/* If we get here, code < 0 and we have network/Server troubles.
	 * areq->networkError is not set here, since we always
	 * retry in case there is another server.  However, if we find
	 * no connection (aconn == 0) we set the networkError flag.
	 */
	afs_MarkServerUpOrDown(sa, SRVR_ISDOWN);
	if (aerrP)
	    (aerrP->err_Server)++;
	VSleep(1);		/* Just a hack for desperate times. */
	shouldRetry = 1;
    }
out:
    /* now unlock the connection and return */
    afs_PutConn(aconn, locktype);
    return (shouldRetry);
}				/*afs_Analyze */
Beispiel #6
0
int
afs_BioDaemon(afs_int32 nbiods)
{
    afs_int32 code, s, pflg = 0;
    label_t jmpbuf;
    struct buf *bp, *bp1, *tbp1, *tbp2;	/* temp pointers only */
    caddr_t tmpaddr;
    struct vnode *vp;
    struct vcache *vcp;
    char tmperr;
    if (!afs_initbiod) {
	/* XXX ###1 XXX */
	afs_initbiod = 1;
	/* pin lock, since we'll be using it in an interrupt. */
	lock_alloc(&afs_asyncbuf_lock, LOCK_ALLOC_PIN, 2, 1);
	simple_lock_init(&afs_asyncbuf_lock);
	pin(&afs_asyncbuf, sizeof(struct buf *));
	pin(&afs_asyncbuf_cv, sizeof(afs_int32));
    }

    /* Ignore HUP signals... */
    {
	sigset_t sigbits, osigbits;
	/*
	 * add SIGHUP to the set of already masked signals
	 */
	SIGFILLSET(sigbits);	/* allow all signals    */
	SIGDELSET(sigbits, SIGHUP);	/*   except SIGHUP      */
	limit_sigs(&sigbits, &osigbits);	/*   and already masked */
    }
    /* Main body starts here -- this is an intentional infinite loop, and
     * should NEVER exit
     *
     * Now, the loop will exit if get_bioreq() returns NULL, indicating
     * that we've been interrupted.
     */
    while (1) {
	bp = afs_get_bioreq();
	if (!bp)
	    break;		/* we were interrupted */
	if (code = setjmpx(&jmpbuf)) {
	    /* This should not have happend, maybe a lack of resources  */
	    AFS_GUNLOCK();
	    s = disable_lock(INTMAX, &afs_asyncbuf_lock);
	    for (bp1 = bp; bp; bp = bp1) {
		if (bp1)
		    bp1 = (struct buf *)bp1->b_work;
		bp->b_actf = 0;
		bp->b_error = code;
		bp->b_flags |= B_ERROR;
		iodone(bp);
	    }
	    unlock_enable(s, &afs_asyncbuf_lock);
	    AFS_GLOCK();
	    continue;
	}
	vcp = VTOAFS(bp->b_vp);
	if (bp->b_flags & B_PFSTORE) {	/* XXXX */
	    ObtainWriteLock(&vcp->lock, 404);
	    if (vcp->v.v_gnode->gn_mwrcnt) {
		afs_offs_t newlength =
		    (afs_offs_t) dbtob(bp->b_blkno) + bp->b_bcount;
		if (vcp->f.m.Length < newlength) {
		    afs_Trace4(afs_iclSetp, CM_TRACE_SETLENGTH,
			       ICL_TYPE_STRING, __FILE__, ICL_TYPE_LONG,
			       __LINE__, ICL_TYPE_OFFSET,
			       ICL_HANDLE_OFFSET(vcp->f.m.Length),
			       ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(newlength));
		    vcp->f.m.Length = newlength;
		}
	    }
	    ReleaseWriteLock(&vcp->lock);
	}
	/* If the buffer represents a protection violation, rather than
	 * an actual request for I/O, no special action need be taken.
	 */
	if (bp->b_flags & B_PFPROT) {
	    iodone(bp);		/* Notify all users of the buffer that we're done */
	    clrjmpx(&jmpbuf);
	    continue;
	}
	if (DOvmlock)
	    ObtainWriteLock(&vcp->pvmlock, 211);
	/*
	 * First map its data area to a region in the current address space
	 * by calling vm_att with the subspace identifier, and a pointer to
	 * the data area.  vm_att returns  a new data area pointer, but we
	 * also want to hang onto the old one.
	 */
	tmpaddr = bp->b_baddr;
	bp->b_baddr = (caddr_t) vm_att(bp->b_xmemd.subspace_id, tmpaddr);
	tmperr = afs_ustrategy(bp);	/* temp variable saves offset calculation */
	if (tmperr) {		/* in non-error case */
	    bp->b_flags |= B_ERROR;	/* should other flags remain set ??? */
	    bp->b_error = tmperr;
	}

	/* Unmap the buffer's data area by calling vm_det.  Reset data area
	 * to the value that we saved above.
	 */
	vm_det(bp->b_baddr);
	bp->b_baddr = tmpaddr;

	/*
	 * buffer may be linked with other buffers via the b_work field.
	 * See also afs_gn_strategy.  For each buffer in the chain (including
	 * bp) notify all users of the buffer that the daemon is finished
	 * using it by calling iodone.
	 * assumes iodone can modify the b_work field.
	 */
	for (tbp1 = bp;;) {
	    tbp2 = (struct buf *)tbp1->b_work;
	    iodone(tbp1);
	    if (!tbp2)
		break;

	    tbp1 = (struct buf *)tbp2->b_work;
	    iodone(tbp2);
	    if (!tbp1)
		break;
	}
	if (DOvmlock)
	    ReleaseWriteLock(&vcp->pvmlock);	/* Unlock the vnode.  */
	clrjmpx(&jmpbuf);
    }				/* infinite loop (unless we're interrupted) */
}				/* end of afs_BioDaemon() */
int
afs_MemRead(register struct vcache *avc, struct uio *auio,
            struct AFS_UCRED *acred, daddr_t albn, struct buf **abpp,
            int noLock)
{
    afs_size_t totalLength;
    afs_size_t transferLength;
    afs_size_t filePos;
    afs_size_t offset, len, tlen;
    afs_int32 trimlen;
    struct dcache *tdc = 0;
    afs_int32 error, trybusy = 1;
#ifdef AFS_DARWIN80_ENV
    uio_t tuiop = NULL;
#else
    struct uio tuio;
    struct uio *tuiop = &tuio;
    struct iovec *tvec;
#endif
    afs_int32 code;
    struct vrequest treq;

    AFS_STATCNT(afs_MemRead);
    if (avc->vc_error)
        return EIO;

    /* check that we have the latest status info in the vnode cache */
    if ((code = afs_InitReq(&treq, acred)))
        return code;
    if (!noLock) {
        code = afs_VerifyVCache(avc, &treq);
        if (code) {
            code = afs_CheckCode(code, &treq, 8);	/* failed to get it */
            return code;
        }
    }
#ifndef	AFS_VM_RDWR_ENV
    if (AFS_NFSXLATORREQ(acred)) {
        if (!afs_AccessOK
                (avc, PRSFS_READ, &treq,
                 CHECK_MODE_BITS | CMB_ALLOW_EXEC_AS_READ)) {
            return afs_CheckCode(EACCES, &treq, 9);
        }
    }
#endif

#ifndef AFS_DARWIN80_ENV
    tvec = (struct iovec *)osi_AllocSmallSpace(sizeof(struct iovec));
#endif
    totalLength = AFS_UIO_RESID(auio);
    filePos = AFS_UIO_OFFSET(auio);
    afs_Trace4(afs_iclSetp, CM_TRACE_READ, ICL_TYPE_POINTER, avc,
               ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(filePos), ICL_TYPE_INT32,
               totalLength, ICL_TYPE_OFFSET,
               ICL_HANDLE_OFFSET(avc->f.m.Length));
    error = 0;
    transferLength = 0;
    if (!noLock)
        ObtainReadLock(&avc->lock);
#if	defined(AFS_TEXT_ENV) && !defined(AFS_VM_RDWR_ENV)
    if (avc->flushDV.high == AFS_MAXDV && avc->flushDV.low == AFS_MAXDV) {
        hset(avc->flushDV, avc->f.m.DataVersion);
    }
#endif

    /*
     * Locks held:
     * avc->lock(R)
     */
    if (filePos >= avc->f.m.Length) {
        if (len > AFS_ZEROS)
            len = sizeof(afs_zeros);	/* and in 0 buffer */
        len = 0;
#ifdef AFS_DARWIN80_ENV
        trimlen = len;
        tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
        afsio_copy(auio, &tuio, tvec);
        trimlen = len;
        afsio_trim(&tuio, trimlen);
#endif
        AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
    }

    while (avc->f.m.Length > 0 && totalLength > 0) {
        /* read all of the cached info */
        if (filePos >= avc->f.m.Length)
            break;		/* all done */
        if (noLock) {
            if (tdc) {
                ReleaseReadLock(&tdc->lock);
                afs_PutDCache(tdc);
            }
            tdc = afs_FindDCache(avc, filePos);
            if (tdc) {
                ObtainReadLock(&tdc->lock);
                offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                len = tdc->f.chunkBytes - offset;
            }
        } else {
            /* a tricky question: does the presence of the DFFetching flag
             * mean that we're fetching the latest version of the file?  No.
             * The server could update the file as soon as the fetch responsible
             * for the setting of the DFFetching flag completes.
             *
             * However, the presence of the DFFetching flag (visible under
             * a dcache read lock since it is set and cleared only under a
             * dcache write lock) means that we're fetching as good a version
             * as was known to this client at the time of the last call to
             * afs_VerifyVCache, since the latter updates the stat cache's
             * m.DataVersion field under a vcache write lock, and from the
             * time that the DFFetching flag goes on in afs_GetDCache (before
             * the fetch starts), to the time it goes off (after the fetch
             * completes), afs_GetDCache keeps at least a read lock on the
             * vcache entry.
             *
             * This means that if the DFFetching flag is set, we can use that
             * data for any reads that must come from the current version of
             * the file (current == m.DataVersion).
             *
             * Another way of looking at this same point is this: if we're
             * fetching some data and then try do an afs_VerifyVCache, the
             * VerifyVCache operation will not complete until after the
             * DFFetching flag is turned off and the dcache entry's f.versionNo
             * field is updated.
             *
             * Note, by the way, that if DFFetching is set,
             * m.DataVersion > f.versionNo (the latter is not updated until
             * after the fetch completes).
             */
            if (tdc) {
                ReleaseReadLock(&tdc->lock);
                afs_PutDCache(tdc);	/* before reusing tdc */
            }
            tdc = afs_GetDCache(avc, filePos, &treq, &offset, &len, 2);
            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:
                if (trybusy && !afs_BBusy()) {
                    struct brequest *bp;
                    /* daemon is not busy */
                    ObtainSharedLock(&tdc->mflock, 665);
                    if (!(tdc->mflags & DFFetchReq)) {
                        /* start the daemon (may already be running, however) */
                        UpgradeSToWLock(&tdc->mflock, 666);
                        tdc->mflags |= DFFetchReq;
                        bp = afs_BQueue(BOP_FETCH, avc, B_DONTWAIT, 0, acred,
                                        (afs_size_t) filePos, (afs_size_t) 0,
                                        tdc);
                        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;
            while (!code && (tdc->dflags & DFFetching)
                    && tdc->validPos <= filePos) {
                /* too early: wait for DFFetching flag to vanish,
                 * or data to appear */
                afs_Trace4(afs_iclSetp, CM_TRACE_DCACHEWAIT, ICL_TYPE_STRING,
                           __FILE__, ICL_TYPE_INT32, __LINE__,
                           ICL_TYPE_POINTER, tdc, ICL_TYPE_INT32,
                           tdc->dflags);
                ReleaseReadLock(&tdc->lock);
                ReleaseReadLock(&avc->lock);
                code = afs_osi_SleepSig(&tdc->validPos);
                ObtainReadLock(&avc->lock);
                ObtainReadLock(&tdc->lock);
            }
            if (code) {
                error = code;
                break;
            }
            /* fetching flag gone, data is here, or we never tried
             * (BBusy for instance) */
            if (tdc->dflags & DFFetching) {
                /* still fetching, some new data is here:
                 * compute length and offset */
                offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                len = tdc->validPos - filePos;
            } else {
                /* no longer fetching, verify data version
                 * (avoid new GetDCache call) */
                if (hsame(avc->f.m.DataVersion, tdc->f.versionNo)
                        && ((len = tdc->validPos - filePos) > 0)) {
                    offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                } else {
                    /* don't have current data, so get it below */
                    afs_Trace3(afs_iclSetp, CM_TRACE_VERSIONNO,
                               ICL_TYPE_INT64, ICL_HANDLE_OFFSET(filePos),
                               ICL_TYPE_HYPER, &avc->f.m.DataVersion,
                               ICL_TYPE_HYPER, &tdc->f.versionNo);
                    ReleaseReadLock(&tdc->lock);
                    afs_PutDCache(tdc);
                    tdc = NULL;
                }
            }

            if (!tdc) {
                /* If we get, it was not possible to start the
                 * background daemon. With flag == 1 afs_GetDCache
                 * does the FetchData rpc synchronously.
                 */
                ReleaseReadLock(&avc->lock);
                tdc = afs_GetDCache(avc, filePos, &treq, &offset, &len, 1);
                ObtainReadLock(&avc->lock);
                if (tdc)
                    ObtainReadLock(&tdc->lock);
            }
        }

        afs_Trace3(afs_iclSetp, CM_TRACE_VNODEREAD, ICL_TYPE_POINTER, tdc,
                   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(offset),
                   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(len));
        if (!tdc) {
            error = EIO;
            break;
        }

        /*
         * Locks held:
         * avc->lock(R)
         * tdc->lock(R)
         */

        if (len > totalLength)
            len = totalLength;	/* will read len bytes */
        if (len <= 0) {		/* shouldn't get here if DFFetching is on */
            /* read past the end of a chunk, may not be at next chunk yet, and yet
             * also not at eof, so may have to supply fake zeros */
            len = AFS_CHUNKTOSIZE(tdc->f.chunk) - offset;	/* bytes left in chunk addr space */
            if (len > totalLength)
                len = totalLength;	/* and still within xfr request */
            tlen = avc->f.m.Length - offset;	/* and still within file */
            if (len > tlen)
                len = tlen;
            if (len > AFS_ZEROS)
                len = sizeof(afs_zeros);	/* and in 0 buffer */
#ifdef AFS_DARWIN80_ENV
            trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
            afsio_copy(auio, &tuio, tvec);
            trimlen = len;
            afsio_trim(&tuio, trimlen);
#endif
            AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
            if (code) {
                error = code;
                break;
            }
        } else {
            /* get the data from the mem cache */

            /* mung uio structure to be right for this transfer */
#ifdef AFS_DARWIN80_ENV
            trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
            uio_setoffset(tuiop, offset);
#else
            afsio_copy(auio, &tuio, tvec);
            trimlen = len;
            afsio_trim(&tuio, trimlen);
            tuio.afsio_offset = offset;
#endif

            code = afs_MemReadUIO(tdc->f.inode, tuiop);

            if (code) {
                error = code;
                break;
            }
        }
        /* otherwise we've read some, fixup length, etc and continue with next seg */
        len = len - AFS_UIO_RESID(tuiop);	/* compute amount really transferred */
        trimlen = len;
        afsio_skip(auio, trimlen);	/* update input uio structure */
        totalLength -= len;
        transferLength += len;
        filePos += len;

        if (len <= 0)
            break;		/* surprise eof */
#ifdef AFS_DARWIN80_ENV
        if (tuiop) {
            uio_free(tuiop);
            tuiop = 0;
        }
#endif
    }				/* the whole while loop */

    /*
     * Locks held:
     * avc->lock(R)
     * tdc->lock(R) if tdc
     */

    /* if we make it here with tdc non-zero, then it is the last chunk we
     * dealt with, and we have to release it when we're done.  We hold on
     * to it in case we need to do a prefetch.
     */
    if (tdc) {
        ReleaseReadLock(&tdc->lock);
        /* try to queue prefetch, if needed */
        if (!noLock &&
#ifndef AFS_VM_RDWR_ENV
                afs_preCache
#else
                1
#endif
           ) {
            afs_PrefetchChunk(avc, tdc, acred, &treq);
        }
        afs_PutDCache(tdc);
    }
    if (!noLock)
        ReleaseReadLock(&avc->lock);
#ifdef AFS_DARWIN80_ENV
    if (tuiop)
        uio_free(tuiop);
#else
    osi_FreeSmallSpace(tvec);
#endif
    error = afs_CheckCode(error, &treq, 10);
    return error;
}
int
afs_UFSRead(register struct vcache *avc, struct uio *auio,
            struct AFS_UCRED *acred, daddr_t albn, struct buf **abpp,
            int noLock)
{
    afs_size_t totalLength;
    afs_size_t transferLength;
    afs_size_t filePos;
    afs_size_t offset, len, tlen;
    afs_int32 trimlen;
    struct dcache *tdc = 0;
    afs_int32 error;
#ifdef AFS_DARWIN80_ENV
    uio_t tuiop=NULL;
#else
    struct uio tuio;
    struct uio *tuiop = &tuio;
    struct iovec *tvec;
#endif
    struct osi_file *tfile;
    afs_int32 code;
    int trybusy = 1;
    struct vrequest treq;

    AFS_STATCNT(afs_UFSRead);
    if (avc && avc->vc_error)
        return EIO;

    AFS_DISCON_LOCK();

    /* check that we have the latest status info in the vnode cache */
    if ((code = afs_InitReq(&treq, acred)))
        return code;
    if (!noLock) {
        if (!avc)
            osi_Panic("null avc in afs_UFSRead");
        else {
            code = afs_VerifyVCache(avc, &treq);
            if (code) {
                code = afs_CheckCode(code, &treq, 11);	/* failed to get it */
                AFS_DISCON_UNLOCK();
                return code;
            }
        }
    }
#ifndef	AFS_VM_RDWR_ENV
    if (AFS_NFSXLATORREQ(acred)) {
        if (!afs_AccessOK
                (avc, PRSFS_READ, &treq,
                 CHECK_MODE_BITS | CMB_ALLOW_EXEC_AS_READ)) {
            AFS_DISCON_UNLOCK();
            return afs_CheckCode(EACCES, &treq, 12);
        }
    }
#endif

#ifndef AFS_DARWIN80_ENV
    tvec = (struct iovec *)osi_AllocSmallSpace(sizeof(struct iovec));
#endif
    totalLength = AFS_UIO_RESID(auio);
    filePos = AFS_UIO_OFFSET(auio);
    afs_Trace4(afs_iclSetp, CM_TRACE_READ, ICL_TYPE_POINTER, avc,
               ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(filePos), ICL_TYPE_INT32,
               totalLength, ICL_TYPE_OFFSET,
               ICL_HANDLE_OFFSET(avc->f.m.Length));
    error = 0;
    transferLength = 0;
    if (!noLock)
        ObtainReadLock(&avc->lock);
#if	defined(AFS_TEXT_ENV) && !defined(AFS_VM_RDWR_ENV)
    if (avc->flushDV.high == AFS_MAXDV && avc->flushDV.low == AFS_MAXDV) {
        hset(avc->flushDV, avc->f.m.DataVersion);
    }
#endif

    if (filePos >= avc->f.m.Length) {
        if (len > AFS_ZEROS)
            len = sizeof(afs_zeros);	/* and in 0 buffer */
        len = 0;
#ifdef AFS_DARWIN80_ENV
        trimlen = len;
        tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
        afsio_copy(auio, &tuio, tvec);
        trimlen = len;
        afsio_trim(&tuio, trimlen);
#endif
        AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
    }

    while (avc->f.m.Length > 0 && totalLength > 0) {
        /* read all of the cached info */
        if (filePos >= avc->f.m.Length)
            break;		/* all done */
        if (noLock) {
            if (tdc) {
                ReleaseReadLock(&tdc->lock);
                afs_PutDCache(tdc);
            }
            tdc = afs_FindDCache(avc, filePos);
            if (tdc) {
                ObtainReadLock(&tdc->lock);
                offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                len = tdc->validPos - filePos;
            }
        } else {
            /* a tricky question: does the presence of the DFFetching flag
             * mean that we're fetching the latest version of the file?  No.
             * The server could update the file as soon as the fetch responsible
             * for the setting of the DFFetching flag completes.
             *
             * However, the presence of the DFFetching flag (visible under
             * a dcache read lock since it is set and cleared only under a
             * dcache write lock) means that we're fetching as good a version
             * as was known to this client at the time of the last call to
             * afs_VerifyVCache, since the latter updates the stat cache's
             * m.DataVersion field under a vcache write lock, and from the
             * time that the DFFetching flag goes on in afs_GetDCache (before
             * the fetch starts), to the time it goes off (after the fetch
             * completes), afs_GetDCache keeps at least a read lock on the
             * vcache entry.
             *
             * This means that if the DFFetching flag is set, we can use that
             * data for any reads that must come from the current version of
             * the file (current == m.DataVersion).
             *
             * Another way of looking at this same point is this: if we're
             * fetching some data and then try do an afs_VerifyVCache, the
             * VerifyVCache operation will not complete until after the
             * DFFetching flag is turned off and the dcache entry's f.versionNo
             * field is updated.
             *
             * Note, by the way, that if DFFetching is set,
             * m.DataVersion > f.versionNo (the latter is not updated until
             * after the fetch completes).
             */
            if (tdc) {
                ReleaseReadLock(&tdc->lock);
                afs_PutDCache(tdc);	/* before reusing tdc */
            }
            tdc = afs_GetDCache(avc, filePos, &treq, &offset, &len, 2);
#ifdef AFS_DISCON_ENV
            if (!tdc) {
                printf("Network down in afs_read");
                error = ENETDOWN;
                break;
            }
#endif /* AFS_DISCON_ENV */

            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:
                if (trybusy && !afs_BBusy()) {
                    struct brequest *bp;
                    /* daemon is not busy */
                    ObtainSharedLock(&tdc->mflock, 667);
                    if (!(tdc->mflags & DFFetchReq)) {
                        UpgradeSToWLock(&tdc->mflock, 668);
                        tdc->mflags |= DFFetchReq;
                        bp = afs_BQueue(BOP_FETCH, avc, B_DONTWAIT, 0, acred,
                                        (afs_size_t) filePos, (afs_size_t) 0,
                                        tdc);
                        if (!bp) {
                            /* Bkg table full; retry deadlocks */
                            tdc->mflags &= ~DFFetchReq;
                            trybusy = 0;	/* Avoid bkg daemon since they're too busy */
                            ReleaseWriteLock(&tdc->mflock);
                            goto tagain;
                        }
                        ConvertWToSLock(&tdc->mflock);
                    }
                    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;
            while (!code && (tdc->dflags & DFFetching)
                    && tdc->validPos <= filePos) {
                /* too early: wait for DFFetching flag to vanish,
                 * or data to appear */
                afs_Trace4(afs_iclSetp, CM_TRACE_DCACHEWAIT, ICL_TYPE_STRING,
                           __FILE__, ICL_TYPE_INT32, __LINE__,
                           ICL_TYPE_POINTER, tdc, ICL_TYPE_INT32,
                           tdc->dflags);
                ReleaseReadLock(&tdc->lock);
                ReleaseReadLock(&avc->lock);
                code = afs_osi_SleepSig(&tdc->validPos);
                ObtainReadLock(&avc->lock);
                ObtainReadLock(&tdc->lock);
            }
            if (code) {
                error = code;
                break;
            }
            /* fetching flag gone, data is here, or we never tried
             * (BBusy for instance) */
            if (tdc->dflags & DFFetching) {
                /* still fetching, some new data is here:
                 * compute length and offset */
                offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                len = tdc->validPos - filePos;
            } else {
                /* no longer fetching, verify data version (avoid new
                 * GetDCache call) */
                if (hsame(avc->f.m.DataVersion, tdc->f.versionNo)
                        && ((len = tdc->validPos - filePos) > 0)) {
                    offset = filePos - AFS_CHUNKTOBASE(tdc->f.chunk);
                } else {
                    /* don't have current data, so get it below */
                    afs_Trace3(afs_iclSetp, CM_TRACE_VERSIONNO,
                               ICL_TYPE_INT64, ICL_HANDLE_OFFSET(filePos),
                               ICL_TYPE_HYPER, &avc->f.m.DataVersion,
                               ICL_TYPE_HYPER, &tdc->f.versionNo);
                    ReleaseReadLock(&tdc->lock);
                    afs_PutDCache(tdc);
                    tdc = NULL;
                }
            }

            if (!tdc) {
                /* If we get, it was not possible to start the
                 * background daemon. With flag == 1 afs_GetDCache
                 * does the FetchData rpc synchronously.
                 */
                ReleaseReadLock(&avc->lock);
                tdc = afs_GetDCache(avc, filePos, &treq, &offset, &len, 1);
                ObtainReadLock(&avc->lock);
                if (tdc)
                    ObtainReadLock(&tdc->lock);
            }
        }

        if (!tdc) {
            error = EIO;
            break;
        }
        len = tdc->validPos - filePos;
        afs_Trace3(afs_iclSetp, CM_TRACE_VNODEREAD, ICL_TYPE_POINTER, tdc,
                   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(offset),
                   ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(len));
        if (len > totalLength)
            len = totalLength;	/* will read len bytes */
        if (len <= 0) {		/* shouldn't get here if DFFetching is on */
            afs_Trace4(afs_iclSetp, CM_TRACE_VNODEREAD2, ICL_TYPE_POINTER,
                       tdc, ICL_TYPE_OFFSET, ICL_HANDLE_OFFSET(tdc->validPos),
                       ICL_TYPE_INT32, tdc->f.chunkBytes, ICL_TYPE_INT32,
                       tdc->dflags);
            /* read past the end of a chunk, may not be at next chunk yet, and yet
             * also not at eof, so may have to supply fake zeros */
            len = AFS_CHUNKTOSIZE(tdc->f.chunk) - offset;	/* bytes left in chunk addr space */
            if (len > totalLength)
                len = totalLength;	/* and still within xfr request */
            tlen = avc->f.m.Length - offset;	/* and still within file */
            if (len > tlen)
                len = tlen;
            if (len > AFS_ZEROS)
                len = sizeof(afs_zeros);	/* and in 0 buffer */
#ifdef AFS_DARWIN80_ENV
            trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
#else
            afsio_copy(auio, &tuio, tvec);
            trimlen = len;
            afsio_trim(&tuio, trimlen);
#endif
            AFS_UIOMOVE(afs_zeros, trimlen, UIO_READ, tuiop, code);
            if (code) {
                error = code;
                break;
            }
        } else {
            /* get the data from the file */
#ifdef IHINT
            if (tfile = tdc->ihint) {
                if (tdc->f.inode != tfile->inum) {
                    afs_warn("afs_UFSRead: %x hint mismatch tdc %d inum %d\n",
                             tdc, tdc->f.inode, tfile->inum);
                    osi_UFSClose(tfile);
                    tdc->ihint = tfile = 0;
                    nihints--;
                }
            }
            if (tfile != 0) {
                usedihint++;
            } else
#endif /* IHINT */
#if defined(LINUX_USE_FH)
                tfile = (struct osi_file *)osi_UFSOpen_fh(&tdc->f.fh, tdc->f.fh_type);
#else
                tfile = (struct osi_file *)osi_UFSOpen(tdc->f.inode);
#endif
#ifdef AFS_DARWIN80_ENV
            trimlen = len;
            tuiop = afsio_darwin_partialcopy(auio, trimlen);
            uio_setoffset(tuiop, offset);
#else
            /* mung uio structure to be right for this transfer */
            afsio_copy(auio, &tuio, tvec);
            trimlen = len;
            afsio_trim(&tuio, trimlen);
            tuio.afsio_offset = offset;
#endif

#if defined(AFS_AIX41_ENV)
            AFS_GUNLOCK();
            code =
                VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, &tuio, NULL, NULL,
                          NULL, afs_osi_credp);
            AFS_GLOCK();
#elif defined(AFS_AIX32_ENV)
            code =
                VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, &tuio, NULL, NULL);
            /* Flush all JFS pages now for big performance gain in big file cases
             * If we do something like this, must check to be sure that AFS file
             * isn't mmapped... see afs_gn_map() for why.
             */
            /*
            	  if (tfile->vnode->v_gnode && tfile->vnode->v_gnode->gn_seg) {
             many different ways to do similar things:
               so far, the best performing one is #2, but #1 might match it if we
               straighten out the confusion regarding which pages to flush.  It
               really does matter.
               1.	    vm_flushp(tfile->vnode->v_gnode->gn_seg, 0, len/PAGESIZE - 1);
               2.	    vm_releasep(tfile->vnode->v_gnode->gn_seg, offset/PAGESIZE,
            			(len + PAGESIZE-1)/PAGESIZE);
               3.	    vms_inactive(tfile->vnode->v_gnode->gn_seg) Doesn't work correctly
               4.  	    vms_delete(tfile->vnode->v_gnode->gn_seg) probably also fails
            	    tfile->vnode->v_gnode->gn_seg = NULL;
               5.       deletep
               6.       ipgrlse
               7.       ifreeseg
                      Unfortunately, this seems to cause frequent "cache corruption" episodes.
               	    vm_releasep(tfile->vnode->v_gnode->gn_seg, offset/PAGESIZE,
            			(len + PAGESIZE-1)/PAGESIZE);
            	  }
            */
#elif defined(AFS_AIX_ENV)
            code =
                VNOP_RDWR(tfile->vnode, UIO_READ, FREAD, (off_t) & offset,
                          &tuio, NULL, NULL, -1);
#elif defined(AFS_SUN5_ENV)
            AFS_GUNLOCK();
#ifdef AFS_SUN510_ENV
            {
                caller_context_t ct;

                VOP_RWLOCK(tfile->vnode, 0, &ct);
                code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp, &ct);
                VOP_RWUNLOCK(tfile->vnode, 0, &ct);
            }
#else
            VOP_RWLOCK(tfile->vnode, 0);
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_RWUNLOCK(tfile->vnode, 0);
#endif
            AFS_GLOCK();
#elif defined(AFS_SGI_ENV)
            AFS_GUNLOCK();
            AFS_VOP_RWLOCK(tfile->vnode, VRWLOCK_READ);
            AFS_VOP_READ(tfile->vnode, &tuio, IO_ISLOCKED, afs_osi_credp,
                         code);
            AFS_VOP_RWUNLOCK(tfile->vnode, VRWLOCK_READ);
            AFS_GLOCK();
#elif defined(AFS_OSF_ENV)
            tuio.uio_rw = UIO_READ;
            AFS_GUNLOCK();
            VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp, code);
            AFS_GLOCK();
#elif defined(AFS_HPUX100_ENV)
            AFS_GUNLOCK();
            code = VOP_RDWR(tfile->vnode, &tuio, UIO_READ, 0, afs_osi_credp);
            AFS_GLOCK();
#elif defined(AFS_LINUX20_ENV)
            AFS_GUNLOCK();
            code = osi_rdwr(tfile, &tuio, UIO_READ);
            AFS_GLOCK();
#elif defined(AFS_DARWIN80_ENV)
            AFS_GUNLOCK();
            code = VNOP_READ(tfile->vnode, tuiop, 0, afs_osi_ctxtp);
            AFS_GLOCK();
#elif defined(AFS_DARWIN_ENV)
            AFS_GUNLOCK();
            VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, current_proc());
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_UNLOCK(tfile->vnode, 0, current_proc());
            AFS_GLOCK();
#elif defined(AFS_FBSD80_ENV)
            AFS_GUNLOCK();
            VOP_LOCK(tfile->vnode, LK_EXCLUSIVE);
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_UNLOCK(tfile->vnode, 0);
            AFS_GLOCK();
#elif defined(AFS_FBSD50_ENV)
            AFS_GUNLOCK();
            VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, curthread);
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_UNLOCK(tfile->vnode, 0, curthread);
            AFS_GLOCK();
#elif defined(AFS_XBSD_ENV)
            AFS_GUNLOCK();
            VOP_LOCK(tfile->vnode, LK_EXCLUSIVE, curproc);
            code = VOP_READ(tfile->vnode, &tuio, 0, afs_osi_credp);
            VOP_UNLOCK(tfile->vnode, 0, curproc);
            AFS_GLOCK();
#else
            code = VOP_RDWR(tfile->vnode, &tuio, UIO_READ, 0, afs_osi_credp);
#endif

#ifdef IHINT
            if (!tdc->ihint && nihints < maxIHint) {
                tdc->ihint = tfile;
                nihints++;
            } else
#endif /* IHINT */
                osi_UFSClose(tfile);

            if (code) {
                error = code;
                break;
            }
        }
        /* otherwise we've read some, fixup length, etc and continue with next seg */
        len = len - AFS_UIO_RESID(tuiop);	/* compute amount really transferred */
        trimlen = len;
        afsio_skip(auio, trimlen);	/* update input uio structure */
        totalLength -= len;
        transferLength += len;
        filePos += len;
        if (len <= 0)
            break;		/* surprise eof */
#ifdef AFS_DARWIN80_ENV
        if (tuiop) {
            uio_free(tuiop);
            tuiop = 0;
        }
#endif
    }

    /* if we make it here with tdc non-zero, then it is the last chunk we
     * dealt with, and we have to release it when we're done.  We hold on
     * to it in case we need to do a prefetch, obviously.
     */
    if (tdc) {
        ReleaseReadLock(&tdc->lock);
#if !defined(AFS_VM_RDWR_ENV)
        /* try to queue prefetch, if needed */
        if (!noLock) {
            if (!(tdc->mflags & DFNextStarted))
                afs_PrefetchChunk(avc, tdc, acred, &treq);
        }
#endif
        afs_PutDCache(tdc);
    }
    if (!noLock)
        ReleaseReadLock(&avc->lock);

#ifdef AFS_DARWIN80_ENV
    if (tuiop)
        uio_free(tuiop);
#else
    osi_FreeSmallSpace(tvec);
#endif
    AFS_DISCON_UNLOCK();
    error = afs_CheckCode(error, &treq, 13);
    return error;
}