/*
 * Copyright 2000, International Business Machines Corporation and others.
 * All Rights Reserved.
 * 
 * This software has been released under the terms of the IBM Public
 * License.  For details, see the LICENSE file in the top-level source
 * directory or online at http://www.openafs.org/dl/license10.html
 */

#include <afs/param.h>
#include <afs/stds.h>

#include <windows.h>
#include <winsock2.h>
#include <malloc.h>
#include <string.h>
#include <stdlib.h>
#include <nb30.h>
#include <osi.h>

#include "afsd.h"

extern osi_hyper_t hzero;

/* hash table stuff */
cm_scache_t **cm_hashTablep;
long cm_hashTableSize;
long cm_maxSCaches;
long cm_currentSCaches;

/* LRU stuff */
cm_scache_t *cm_scacheLRUFirstp;
cm_scache_t *cm_scacheLRULastp;

/* File locks */
osi_queue_t *cm_allFileLocks;

/* lock for globals */
osi_rwlock_t cm_scacheLock;

/* Dummy scache entry for use with pioctl fids */
cm_scache_t cm_fakeSCache;

/* must be called with cm_scacheLock write-locked! */
void cm_AdjustLRU(cm_scache_t *scp)
{
	if (scp == cm_scacheLRULastp)
		cm_scacheLRULastp = (cm_scache_t *) osi_QPrev(&scp->q);
	osi_QRemove((osi_queue_t **) &cm_scacheLRUFirstp, &scp->q);
	osi_QAdd((osi_queue_t **) &cm_scacheLRUFirstp, &scp->q);
	if (!cm_scacheLRULastp) cm_scacheLRULastp = scp;
}

/* called with cm_scacheLock write-locked; find a vnode to recycle.
 * Can allocate a new one if desperate, or if below quota (cm_maxSCaches).
 */
cm_scache_t *cm_GetNewSCache(void)
{
	cm_scache_t *scp;
        int i;
        cm_scache_t **lscpp;
        cm_scache_t *tscp;

	if (cm_currentSCaches >= cm_maxSCaches) {
     	        for (scp = cm_scacheLRULastp;
     		     scp;
     		     scp = (cm_scache_t *) osi_QPrev(&scp->q)) {
		  if (scp->refCount == 0) break;
	        }
                
                if (scp) {
			/* we found an entry, so return it */
                        if (scp->flags & CM_SCACHEFLAG_INHASH) {
				/* hash it out first */
                                i = CM_SCACHE_HASH(&scp->fid);
				lscpp = &cm_hashTablep[i];
				for (tscp = *lscpp;
     				     tscp;
     				     lscpp = &tscp->nextp, tscp = *lscpp) {
				  if (tscp == scp) break;
                                }
                                osi_assertx(tscp, "afsd: scache hash screwup");
                                *lscpp = scp->nextp;
                                scp->flags &= ~CM_SCACHEFLAG_INHASH;
                        }

			/* look for things that shouldn't still be set */
                        osi_assert(scp->bufWritesp == NULL);
                        osi_assert(scp->bufReadsp == NULL);

			/* invalidate so next merge works fine;
			 * also initialize some flags */
                        scp->flags &= ~(CM_SCACHEFLAG_STATD
					| CM_SCACHEFLAG_RO
					| CM_SCACHEFLAG_PURERO
					| CM_SCACHEFLAG_OVERQUOTA
					| CM_SCACHEFLAG_OUTOFSPACE);
                        scp->serverModTime = 0;
                        scp->dataVersion = 0;
			scp->bulkStatProgress = hzero;

                        /* discard callback */
                        scp->cbServerp = NULL;
                        scp->cbExpires = 0;

			/* remove from dnlc */
			cm_dnlcPurgedp(scp);
			cm_dnlcPurgevp(scp);

			/* discard cached status; if non-zero, Close
			 * tried to store this to server but failed */
			scp->mask = 0;

			/* drop held volume ref */
			if (scp->volp) {
				cm_PutVolume(scp->volp);
				scp->volp = NULL;
			}

                        /* discard symlink info */
                        if (scp->mountPointStringp) {
                        	free(scp->mountPointStringp);
                                scp->mountPointStringp = NULL;
			}
			if (scp->mountRootFidp) {
				free(scp->mountRootFidp);
				scp->mountRootFidp = NULL;
			}
			if (scp->dotdotFidp) {
				free(scp->dotdotFidp);
				scp->dotdotFidp = NULL;
			}
                        
			/* not locked, but there can be no references to this guy
                         * while we hold the global refcount lock.
                         */
                        cm_FreeAllACLEnts(scp);
                        
                        /* now remove from the LRU queue and put it back at the
                         * head of the LRU queue.
                         */
			cm_AdjustLRU(scp);
			
                        /* and we're done */
                        return scp;
                }
	}
        
        /* if we get here, we should allocate a new scache entry.  We either are below
         * quota or we have a leak and need to allocate a new one to avoid panicing.
         */
        scp = malloc(sizeof(*scp));
        memset(scp, 0, sizeof(*scp));
	lock_InitializeMutex(&scp->mx, "cm_scache_t mutex");
        lock_InitializeRWLock(&scp->bufCreateLock, "cm_scache_t bufCreateLock");
	
        /* and put it in the LRU queue */
        osi_QAdd((osi_queue_t **) &cm_scacheLRUFirstp, &scp->q);
        if (!cm_scacheLRULastp) cm_scacheLRULastp = scp;
        cm_currentSCaches++;
	cm_dnlcPurgedp(scp); /* make doubly sure that this is not in dnlc */
	cm_dnlcPurgevp(scp); 
        return scp;
}

/* like strcmp, only for fids */
int cm_FidCmp(cm_fid_t *ap, cm_fid_t *bp)
{
        if (ap->vnode != bp->vnode) return 1;
	if (ap->volume != bp->volume) return 1;
        if (ap->unique != bp->unique) return 1;
        if (ap->cell != bp->cell) return 1;
        return 0;
}

void cm_fakeSCacheInit()
{
	memset(&cm_fakeSCache, 0, sizeof(cm_fakeSCache));
	lock_InitializeMutex(&cm_fakeSCache.mx, "cm_scache_t mutex");
	cm_fakeSCache.cbServerp = (struct cm_server *)(-1);
	/* can leave clientModTime at 0 */
	cm_fakeSCache.fileType = CM_SCACHETYPE_FILE;
	cm_fakeSCache.unixModeBits = 0777;
	cm_fakeSCache.length.LowPart = 1000;
	cm_fakeSCache.linkCount = 1;
}

void cm_InitSCache(long maxSCaches)
{
	static osi_once_t once;
        
        if (osi_Once(&once)) {
		lock_InitializeRWLock(&cm_scacheLock, "cm_scacheLock");
                cm_hashTableSize = maxSCaches / 2;
                cm_hashTablep = malloc(sizeof(cm_scache_t *) * cm_hashTableSize);
                memset(cm_hashTablep, 0, sizeof(cm_scache_t *) * cm_hashTableSize);
		cm_allFileLocks = NULL;
                cm_currentSCaches = 0;
                cm_maxSCaches = maxSCaches;
		cm_fakeSCacheInit();
		cm_dnlcInit();
		osi_EndOnce(&once);
        }
}

/* version that doesn't bother creating the entry if we don't find it */
cm_scache_t *cm_FindSCache(cm_fid_t *fidp)
{
	long hash;
        cm_scache_t *scp;
        
        hash = CM_SCACHE_HASH(fidp);
        
	osi_assert(fidp->cell != 0);

        lock_ObtainWrite(&cm_scacheLock);
	for(scp=cm_hashTablep[hash]; scp; scp=scp->nextp) {
		if (cm_FidCmp(fidp, &scp->fid) == 0) {
			scp->refCount++;
                        cm_AdjustLRU(scp);
                        lock_ReleaseWrite(&cm_scacheLock);
			return scp;
                }
        }
        lock_ReleaseWrite(&cm_scacheLock);
        return NULL;
}

long cm_GetSCache(cm_fid_t *fidp, cm_scache_t **outScpp, cm_user_t *userp,
	cm_req_t *reqp)
{
	long hash;
        cm_scache_t *scp;
        long code;
        cm_volume_t *volp;
        cm_cell_t *cellp;
        
        hash = CM_SCACHE_HASH(fidp);
        
	osi_assert(fidp->cell != 0);

        lock_ObtainWrite(&cm_scacheLock);
	for(scp=cm_hashTablep[hash]; scp; scp=scp->nextp) {
		if (cm_FidCmp(fidp, &scp->fid) == 0) {
			scp->refCount++;
                        *outScpp = scp;
                        cm_AdjustLRU(scp);
                        lock_ReleaseWrite(&cm_scacheLock);
			return 0;
                }
        }
        
        /* otherwise, we need to find the volume */
        lock_ReleaseWrite(&cm_scacheLock);	/* for perf. reasons */
        cellp = cm_FindCellByID(fidp->cell);
        if (!cellp) return CM_ERROR_NOSUCHCELL;

        code = cm_GetVolumeByID(cellp, fidp->volume, userp, reqp, &volp);
        if (code) return code;
        
        /* otherwise, we have the volume, now reverify that the scp doesn't
         * exist, and proceed.
         */
        lock_ObtainWrite(&cm_scacheLock);
	for(scp=cm_hashTablep[hash]; scp; scp=scp->nextp) {
		if (cm_FidCmp(fidp, &scp->fid) == 0) {
			scp->refCount++;
                        cm_AdjustLRU(scp);
                        lock_ReleaseWrite(&cm_scacheLock);
                        cm_PutVolume(volp);
                        *outScpp = scp;
			return 0;
                }
        }
        
        /* now, if we don't have the fid, recycle something */
	scp = cm_GetNewSCache();
	osi_assert(!(scp->flags & CM_SCACHEFLAG_INHASH));
	scp->fid = *fidp;
	scp->volp = volp;	/* a held reference */

	/* if this scache entry represents a volume root then we need 
	 * to copy the dotdotFipd from the volume structure where the 
	 * "master" copy is stored (defect 11489)
	 */
	if(scp->fid.vnode == 1 && scp->fid.unique == 1 && volp->dotdotFidp) {
	        if (scp->dotdotFidp == (cm_fid_t *) NULL)
		        scp->dotdotFidp = (cm_fid_t *) malloc(sizeof(cm_fid_t));
		*(scp->dotdotFidp) = *volp->dotdotFidp;
	}

	if (volp->roID == fidp->volume)
		scp->flags |= (CM_SCACHEFLAG_PURERO | CM_SCACHEFLAG_RO);
	else if (volp->bkID == fidp->volume)
               	scp->flags |= CM_SCACHEFLAG_RO;
	scp->nextp = cm_hashTablep[hash];
	cm_hashTablep[hash] = scp;
        scp->flags |= CM_SCACHEFLAG_INHASH;
	scp->refCount = 1;
        lock_ReleaseWrite(&cm_scacheLock);
        
        /* now we have a held scache entry; just return it */
        *outScpp = scp;
        
        return 0;
}

/* synchronize a fetch, store, read, write, fetch status or store status.
 * Called with scache mutex held, and returns with it held, but temporarily
 * drops it during the fetch.
 * 
 * At most one flag can be on in flags, if this is an RPC request.
 *
 * Also, if we're fetching or storing data, we must ensure that we have a buffer.
 *
 * There are a lot of weird restrictions here; here's an attempt to explain the
 * rationale for the concurrency restrictions implemented in this function.
 *
 * First, although the file server will break callbacks when *another* machine
 * modifies a file or status block, the client itself is responsible for
 * concurrency control on its own requests.  Callback breaking events are rare,
 * and simply invalidate any concurrent new status info.
 *
 * In the absence of callback breaking messages, we need to know how to
 * synchronize incoming responses describing updates to files.  We synchronize
 * operations that update the data version by comparing the data versions.
 * However, updates that do not update the data, but only the status, can't be
 * synchronized with fetches or stores, since there's nothing to compare
 * to tell which operation executed first at the server.
 *
 * Thus, we can allow multiple ops that change file data, or dir data, and
 * fetches.  However, status storing ops have to be done serially.
 *
 * Furthermore, certain data-changing ops are incompatible: we can't read or
 * write a buffer while doing a truncate.  We can't read and write the same
 * buffer at the same time, or write while fetching or storing, or read while
 * fetching a buffer (this may change).  We can't fetch and store at the same
 * time, either.
 *
 * With respect to status, we can't read and write at the same time, read while
 * fetching, write while fetching or storing, or fetch and store at the same time.
 *
 * We can't allow a get callback RPC to run in concurrently with something that
 * will return updated status, since we could start a call, have the server
 * return status, have another machine make an update to the status (which
 * doesn't change serverModTime), have the original machine get a new callback,
 * and then have the original machine merge in the early, old info from the
 * first call.  At this point, the easiest way to avoid this problem is to have
 * getcallback calls conflict with all others for the same vnode.  Other calls
 * to cm_MergeStatus that aren't associated with calls to cm_SyncOp on the same
 * vnode must be careful not to merge in their status unless they have obtained
 * a callback from the start of their call.
 *
 * Note added 1/23/96
 * Concurrent StoreData RPC's can cause trouble if the file is being extended.
 * Each such RPC passes a FileLength parameter, which the server uses to do
 * pre-truncation if necessary.  So if two RPC's are processed out of order at
 * the server, the one with the smaller FileLength will be processed last,
 * possibly resulting in a bogus truncation.  The simplest way to avoid this
 * is to serialize all StoreData RPC's.  This is the reason we defined
 * CM_SCACHESYNC_STOREDATA_EXCL and CM_SCACHEFLAG_DATASTORING.
 */
long cm_SyncOp(cm_scache_t *scp, cm_buf_t *bufp, cm_user_t *up, cm_req_t *reqp,
	long rights, long flags)
{
	osi_queueData_t *qdp;
        long code;
        cm_buf_t *tbufp;
        long outRights;
        int bufLocked;

	/* lookup this first */
	bufLocked = flags & CM_SCACHESYNC_BUFLOCKED;

	/* some minor assertions */
	if (flags & (CM_SCACHESYNC_STOREDATA | CM_SCACHESYNC_FETCHDATA
			| CM_SCACHESYNC_READ | CM_SCACHESYNC_WRITE
			| CM_SCACHESYNC_SETSIZE)) {
		if (bufp) {
			osi_assert(bufp->refCount > 0);
			/*
			osi_assert(cm_FidCmp(&bufp->fid, &scp->fid) == 0);
			 */
		}
	}
	else osi_assert(bufp == NULL);

	/* Do the access check.  Now we don't really do the access check
	 * atomically, since the caller doesn't expect the parent dir to be
	 * returned locked, and that is what we'd have to do to prevent a
	 * callback breaking message on the parent due to a setacl call from
	 * being processed while we're running.  So, instead, we check things
         * here, and if things look fine with the access, we proceed to finish
	 * the rest of this check.  Sort of a hack, but probably good enough.
         */

	while (1) {
		if (flags & CM_SCACHESYNC_FETCHSTATUS) {
			/* if we're bringing in a new status block, ensure that
			 * we aren't already doing so, and that no one is
			 * changing the status concurrently, either.  We need
			 * to do this, even if the status is of a different
                         * type, since we don't have the ability to figure out,
			 * in the AFS 3 protocols, which status-changing
			 * operation ran first, or even which order a read and
			 * a write occurred in.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING | CM_SCACHEFLAG_GETCALLBACK))
				goto sleep;
                }
                if (flags & (CM_SCACHESYNC_STORESIZE | CM_SCACHESYNC_STORESTATUS
                		| CM_SCACHESYNC_SETSIZE | CM_SCACHESYNC_GETCALLBACK)) {
			/* if we're going to make an RPC to change the status, make sure
                         * that no one is bringing in or sending out the status.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING | CM_SCACHEFLAG_GETCALLBACK))
				goto sleep;
			if (scp->bufReadsp || scp->bufWritesp) goto sleep;
                }
                if (flags & CM_SCACHESYNC_FETCHDATA) {
                	/* if we're bringing in a new chunk of data, make sure that
                         * nothing is happening to that chunk, and that we aren't
                         * changing the basic file status info, either.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING | CM_SCACHEFLAG_GETCALLBACK))
				goto sleep;
                        if (bufp && (bufp->cmFlags & (CM_BUF_CMFETCHING | CM_BUF_CMSTORING)))
                        	goto sleep;
                }
                if (flags & CM_SCACHESYNC_STOREDATA) {
			/* same as fetch data */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING | CM_SCACHEFLAG_GETCALLBACK))
				goto sleep;
                        if (bufp && (bufp->cmFlags & (CM_BUF_CMFETCHING | CM_BUF_CMSTORING)))
                        	goto sleep;
                }

		if (flags & CM_SCACHESYNC_STOREDATA_EXCL) {
			/* Don't allow concurrent StoreData RPC's */
			if (scp->flags & CM_SCACHEFLAG_DATASTORING)
				goto sleep;
		}

		if (flags & CM_SCACHESYNC_ASYNCSTORE) {
			/* Don't allow more than one BKG store request */
			if (scp->flags & CM_SCACHEFLAG_ASYNCSTORING)
				goto sleep;
		}

		if (flags & CM_SCACHESYNC_LOCK) {
			/* Don't allow concurrent fiddling with lock lists */
			if (scp->flags & CM_SCACHEFLAG_LOCKING)
				goto sleep;
		}

                /* now the operations that don't correspond to making RPCs */
                if (flags & CM_SCACHESYNC_GETSTATUS) {
			/* we can use the status that's here, if we're not
			 * bringing in new status.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING))
				goto sleep;
                }
		if (flags & CM_SCACHESYNC_SETSTATUS) {
                	/* we can make a change to the local status, as long as
			 * the status isn't changing now.
			 *
                         * If we're fetching or storing a chunk of data, we can
			 * change the status locally, since the fetch/store
			 * operations don't change any of the data that we're
			 * changing here.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING))
				goto sleep;
                }
                if (flags & CM_SCACHESYNC_READ) {
			/* we're going to read the data, make sure that the
			 * status is available, and that the data is here.  It
			 * is OK to read while storing the data back.
                         */
			if (scp->flags & CM_SCACHEFLAG_FETCHING)
				goto sleep;
                        if (bufp && ((bufp->cmFlags
					 & (CM_BUF_CMFETCHING
					     | CM_BUF_CMFULLYFETCHED))
					== CM_BUF_CMFETCHING))
                        	goto sleep;
                }
		if (flags & CM_SCACHESYNC_WRITE) {
			/* don't write unless the status is stable and the chunk
                         * is stable.
                         */
			if (scp->flags & (CM_SCACHEFLAG_FETCHING | CM_SCACHEFLAG_STORING
                        		  | CM_SCACHEFLAG_SIZESTORING))
				goto sleep;
                        if (bufp && (bufp->cmFlags & (CM_BUF_CMFETCHING | CM_BUF_CMSTORING)))
                        	goto sleep;
                }

                if (flags & CM_SCACHESYNC_NEEDCALLBACK) {
			if (!cm_HaveCallback(scp)) {
				osi_Log1(afsd_logp, "CM SyncOp getting callback on scp %x",
                                	(long) scp);
				if (bufLocked) lock_ReleaseMutex(&bufp->mx);
				code = cm_GetCallback(scp, up, reqp, 0);
                                if (bufLocked) {
					lock_ReleaseMutex(&scp->mx);
                                        lock_ObtainMutex(&bufp->mx);
                                        lock_ObtainMutex(&scp->mx);
                                }
                                if (code) return code;
				continue;
                        }
                }
                
		if (rights) {
			/* can't check access rights without a callback */
			osi_assert(flags & CM_SCACHESYNC_NEEDCALLBACK);

			if ((rights & PRSFS_WRITE) && (scp->flags & CM_SCACHEFLAG_RO))
				return CM_ERROR_READONLY;

			if (cm_HaveAccessRights(scp, up, rights, &outRights)) {
				if (~outRights & rights) return CM_ERROR_NOACCESS;
                        }
                        else {
				/* we don't know the required access rights */
				if (bufLocked) lock_ReleaseMutex(&bufp->mx);
                                code = cm_GetAccessRights(scp, up, reqp);
                                if (code) return code;
                                if (bufLocked) {
					lock_ReleaseMutex(&scp->mx);
                                        lock_ObtainMutex(&bufp->mx);
                                        lock_ObtainMutex(&scp->mx);
                                }
                                continue;
                        }
                }

                /* if we get here, we're happy */
                break;

sleep:
		/* first check if we're not supposed to wait: fail 
                 * in this case, returning with everything still locked.
                 */
		if (flags & CM_SCACHESYNC_NOWAIT) return CM_ERROR_WOULDBLOCK;

		/* wait here, then try again */
		osi_Log1(afsd_logp, "CM SyncOp sleeping scp %x", (long) scp);
		scp->flags |= CM_SCACHEFLAG_WAITING;
		if (bufLocked) lock_ReleaseMutex(&bufp->mx);
                osi_SleepM((long) &scp->flags, &scp->mx);
                osi_Log0(afsd_logp, "CM SyncOp woke!");
		if (bufLocked) lock_ObtainMutex(&bufp->mx);
                lock_ObtainMutex(&scp->mx);
        } /* big while loop */
        
        /* now, update the recorded state for RPC-type calls */
        if (flags & CM_SCACHESYNC_FETCHSTATUS)
        	scp->flags |= CM_SCACHEFLAG_FETCHING;
	if (flags & CM_SCACHESYNC_STORESTATUS)
        	scp->flags |= CM_SCACHEFLAG_STORING;
	if (flags & CM_SCACHESYNC_STORESIZE)
        	scp->flags |= CM_SCACHEFLAG_SIZESTORING;
	if (flags & CM_SCACHESYNC_GETCALLBACK)
        	scp->flags |= CM_SCACHEFLAG_GETCALLBACK;
	if (flags & CM_SCACHESYNC_STOREDATA_EXCL)
		scp->flags |= CM_SCACHEFLAG_DATASTORING;
	if (flags & CM_SCACHESYNC_ASYNCSTORE)
		scp->flags |= CM_SCACHEFLAG_ASYNCSTORING;
	if (flags & CM_SCACHESYNC_LOCK)
		scp->flags |= CM_SCACHEFLAG_LOCKING;

	/* now update the buffer pointer */
        if (flags & CM_SCACHESYNC_FETCHDATA) {
		/* ensure that the buffer isn't already in the I/O list */
		if (bufp) {
			for(qdp = scp->bufReadsp; qdp; qdp = (osi_queueData_t *) osi_QNext(&qdp->q)) {
				tbufp = osi_GetQData(qdp);
	                        osi_assert(tbufp != bufp);
	                }
		}
                
		/* queue a held reference to the buffer in the "reading" I/O list */
                qdp = osi_QDAlloc();
                osi_SetQData(qdp, bufp);
		if (bufp) {
	                buf_Hold(bufp);
	                bufp->cmFlags |= CM_BUF_CMFETCHING;
		}
                osi_QAdd((osi_queue_t **) &scp->bufReadsp, &qdp->q);
        }

        if (flags & CM_SCACHESYNC_STOREDATA) {
		/* ensure that the buffer isn't already in the I/O list */
		if (bufp) {
			for(qdp = scp->bufWritesp; qdp; qdp = (osi_queueData_t *) osi_QNext(&qdp->q)) {
				tbufp = osi_GetQData(qdp);
	                        osi_assert(tbufp != bufp);
	                }
		}
                
		/* queue a held reference to the buffer in the "writing" I/O list */
                qdp = osi_QDAlloc();
                osi_SetQData(qdp, bufp);
		if (bufp) {
	                buf_Hold(bufp);
	                bufp->cmFlags |= CM_BUF_CMSTORING;
		}
                osi_QAdd((osi_queue_t **) &scp->bufWritesp, &qdp->q);
        }
        
        return 0;
}

/* for those syncops that setup for RPCs.
 * Called with scache locked.
 */
void cm_SyncOpDone(cm_scache_t *scp, cm_buf_t *bufp, long flags)
{
	osi_queueData_t *qdp;
	cm_buf_t *tbufp;

        /* now, update the recorded state for RPC-type calls */
        if (flags & CM_SCACHESYNC_FETCHSTATUS)
        	scp->flags &= ~CM_SCACHEFLAG_FETCHING;
	if (flags & CM_SCACHESYNC_STORESTATUS)
        	scp->flags &= ~CM_SCACHEFLAG_STORING;
	if (flags & CM_SCACHESYNC_STORESIZE)
        	scp->flags &= ~CM_SCACHEFLAG_SIZESTORING;
	if (flags & CM_SCACHESYNC_GETCALLBACK)
        	scp->flags &= ~CM_SCACHEFLAG_GETCALLBACK;
	if (flags & CM_SCACHESYNC_STOREDATA_EXCL)
		scp->flags &= ~CM_SCACHEFLAG_DATASTORING;
	if (flags & CM_SCACHESYNC_ASYNCSTORE)
		scp->flags &= ~CM_SCACHEFLAG_ASYNCSTORING;
	if (flags & CM_SCACHESYNC_LOCK)
		scp->flags &= ~CM_SCACHEFLAG_LOCKING;

	/* now update the buffer pointer */
        if (flags & CM_SCACHESYNC_FETCHDATA) {
		/* ensure that the buffer isn't already in the I/O list */
		for(qdp = scp->bufReadsp; qdp; qdp = (osi_queueData_t *) osi_QNext(&qdp->q)) {
			tbufp = osi_GetQData(qdp);
			if (tbufp == bufp) break;
                }
                osi_assert(qdp != NULL);
		osi_assert(osi_GetQData(qdp) == bufp);
		osi_QRemove((osi_queue_t **) &scp->bufReadsp, &qdp->q);
                osi_QDFree(qdp);
		if (bufp) {
			bufp->cmFlags &=
			  ~(CM_BUF_CMFETCHING | CM_BUF_CMFULLYFETCHED);
	                buf_Release(bufp);
		}
        }

	/* now update the buffer pointer */
        if (flags & CM_SCACHESYNC_STOREDATA) {
		/* ensure that the buffer isn't already in the I/O list */
		for(qdp = scp->bufWritesp; qdp; qdp = (osi_queueData_t *) osi_QNext(&qdp->q)) {
			tbufp = osi_GetQData(qdp);
			if (tbufp == bufp) break;
                }
                osi_assert(qdp != NULL);
		osi_assert(osi_GetQData(qdp) == bufp);
		osi_QRemove((osi_queue_t **) &scp->bufWritesp, &qdp->q);
                osi_QDFree(qdp);
		if (bufp) {
			bufp->cmFlags &= ~CM_BUF_CMSTORING;
	                buf_Release(bufp);
		}
        }
        
        /* and wakeup anyone who is waiting */
        if (scp->flags & CM_SCACHEFLAG_WAITING) {
		scp->flags &= ~CM_SCACHEFLAG_WAITING;
                osi_Wakeup((long) &scp->flags);
        }
}

/* merge in a response from an RPC.  The scp must be locked, and the callback
 * is optional.
 *
 * Don't overwrite any status info that is dirty, since we could have a store
 * operation (such as store data) that merges some info in, and we don't want
 * to lose the local updates.  Typically, there aren't many updates we do
 * locally, anyway, probably only mtime.
 *
 * There is probably a bug in here where a chmod (which doesn't change
 * serverModTime) that occurs between two fetches, both of whose responses are
 * handled after the callback breaking is done, but only one of whose calls
 * started before that, can cause old info to be merged from the first call.
 */
void cm_MergeStatus(cm_scache_t *scp, AFSFetchStatus *statusp, AFSVolSync *volp,
	cm_user_t *userp, int flags)
{
	if (!(flags & CM_MERGEFLAG_FORCE)
               	&& statusp->DataVersion < (unsigned long) scp->dataVersion) {
		struct cm_cell *cellp;
		struct cm_volume *volp;

		cellp = cm_FindCellByID(scp->fid.cell);
		cm_GetVolumeByID(cellp, scp->fid.volume, userp,
				 (cm_req_t *) NULL, &volp);
		if (scp->cbServerp)
			osi_Log2(afsd_logp, "old data from server %x volume %s",
				 scp->cbServerp->addr.sin_addr.s_addr,
				 volp->namep);
		osi_Log3(afsd_logp, "Bad merge, scp %x, scp dv %d, RPC dv %d",
			 scp, scp->dataVersion, statusp->DataVersion);
		/* we have a number of data fetch/store operations running
		 * concurrently, and we can tell which one executed last at the
		 * server by its mtime.
		 * Choose the one with the largest mtime, and ignore the rest.
		 *
		 * These concurrent calls are incompatible with setting the
		 * mtime, so we won't have a locally changed mtime here.
                 *
                 * We could also have ACL info for a different user than usual,
		 * in which case we have to do that part of the merge, anyway.
		 * We won't have to worry about the info being old, since we
		 * won't have concurrent calls
                 * that change file status running from this machine.
		 *
		 * Added 3/17/98:  if we see data version regression on an RO
		 * file, it's probably due to a server holding an out-of-date
		 * replica, rather than to concurrent RPC's.  Failures to
		 * release replicas are now flagged by the volserver, but only
		 * since AFS 3.4 5.22, so there are plenty of clients getting
		 * out-of-date replicas out there.
		 *
		 * If we discover an out-of-date replica, by this time it's too
		 * late to go to another server and retry.  Also, we can't
		 * reject the merge, because then there is no way for
		 * GetAccess to do its work, and the caller gets into an
		 * infinite loop.  So we just grin and bear it.
		 */
		if (!(scp->flags & CM_SCACHEFLAG_RO))
			return;
	}
        scp->serverModTime = statusp->ServerModTime;

	if (!(scp->mask & CM_SCACHEMASK_CLIENTMODTIME)) {
        	scp->clientModTime = statusp->ClientModTime;
	}
        if (!(scp->mask & CM_SCACHEMASK_LENGTH)) {
        	scp->length.LowPart = statusp->Length;
                scp->length.HighPart = 0;
	}

	scp->serverLength.LowPart = statusp->Length;
	scp->serverLength.HighPart = 0;

	scp->linkCount = statusp->LinkCount;
        scp->dataVersion = statusp->DataVersion;
        scp->owner = statusp->Owner;
        scp->group = statusp->Group;
        scp->unixModeBits = statusp->UnixModeBits & 07777;
        
        if (statusp->FileType == File)
        	scp->fileType = CM_SCACHETYPE_FILE;
	else if (statusp->FileType == Directory)
		scp->fileType = CM_SCACHETYPE_DIRECTORY;
	else if (statusp->FileType == SymbolicLink) {
		if ((scp->unixModeBits & 0111) == 0)
                	scp->fileType = CM_SCACHETYPE_MOUNTPOINT;
		else
                	scp->fileType = CM_SCACHETYPE_SYMLINK;
        }
        else scp->fileType = 0;	/* invalid */

        /* and other stuff */
        scp->parentVnode = statusp->ParentVnode;
        scp->parentUnique = statusp->ParentUnique;
        
        /* and merge in the private acl cache info, if this is more than the public
         * info; merge in the public stuff in any case.
         */
	scp->anyAccess = statusp->AnonymousAccess;

        if (userp != NULL) {
		cm_AddACLCache(scp, userp, statusp->CallerAccess);
        }
}

/* note that our stat cache info is incorrect, so force us eventually
 * to stat the file again.  There may be dirty data associated with
 * this vnode, and we want to preserve that information.
 *
 * This function works by simply simulating a loss of the callback.
 *
 * This function must be called with the scache locked.
 */
void cm_DiscardSCache(cm_scache_t *scp)
{
	lock_AssertMutex(&scp->mx);
	scp->cbServerp = NULL;
        scp->cbExpires = 0;
	cm_dnlcPurgedp(scp);
        cm_FreeAllACLEnts(scp);
}

void cm_AFSFidFromFid(AFSFid *afsFidp, cm_fid_t *fidp)
{
	afsFidp->Volume = fidp->volume;
        afsFidp->Vnode = fidp->vnode;
        afsFidp->Unique = fidp->unique;
}

void cm_HoldSCache(cm_scache_t *scp)
{
	lock_ObtainWrite(&cm_scacheLock);
	osi_assert(scp->refCount > 0);
	scp->refCount++;
	lock_ReleaseWrite(&cm_scacheLock);
}

void cm_ReleaseSCache(cm_scache_t *scp)
{
	lock_ObtainWrite(&cm_scacheLock);
	osi_assert(scp->refCount-- > 0);
	lock_ReleaseWrite(&cm_scacheLock);
}
