/* Copyright (C) 1995, 1989, 1998 Transarc Corporation - All rights reserved */

/*
 * For copyright information, see IPL which you accepted in order to
 * download this software.
 *
 */

/*
 * afs_vnop_link.c
 *
 * Implements:
 * afs_link
 *
 */

#include "../afs/param.h"	/* Should be always first */
#include "../afs/sysincludes.h"	/* Standard vendor system headers */
#include "../afs/afsincludes.h"	/* Afs-based standard headers */
#include "../afs/afs_stats.h" /* statistics */
#include "../afs/afs_cbqueue.h"
#include "../afs/nfsclient.h"
#include "../afs/afs_osidnlc.h"

extern afs_rwlock_t afs_xcbhash;

/* Note that we don't set CDirty here, this is OK because the link
 * RPC is called synchronously. */

#ifdef	AFS_OSF_ENV
afs_link(avc, ndp)
    register struct vcache *avc;
    struct nameidata *ndp; {
    register struct vcache *adp = (struct vcache *)ndp->ni_dvp;
    char *aname = ndp->ni_dent.d_name;
    struct ucred *acred = ndp->ni_cred;
#else	/* AFS_OSF_ENV */
#if	defined(AFS_SUN5_ENV) || defined(AFS_SGI_ENV)
afs_link(OSI_VC_ARG(adp), avc, aname, acred)
#else
afs_link(avc, OSI_VC_ARG(adp), aname, acred)
#endif
    OSI_VC_DECL(adp);
    register struct vcache *avc;
    char *aname;
    struct AFS_UCRED *acred;
{
#endif
    struct vrequest treq;
    register struct dcache *tdc;
    register afs_int32 code;
    register struct conn *tc;
    afs_int32 offset, len;
    struct AFSFetchStatus OutFidStatus, OutDirStatus;
    struct AFSVolSync tsync;
    XSTATS_DECLS
    OSI_VC_CONVERT(adp)

    AFS_STATCNT(afs_link);
    afs_Trace3(afs_iclSetp, CM_TRACE_LINK, ICL_TYPE_POINTER, adp,
	       ICL_TYPE_POINTER, avc, ICL_TYPE_STRING, aname);
    /* create a hard link; new entry is aname in dir adp */
    if (code = afs_InitReq(&treq, acred)) return code;
    if (avc->fid.Cell != adp->fid.Cell || avc->fid.Fid.Volume != adp->fid.Fid.Volume) {
	code = EXDEV;
	goto done;
    }
    code = afs_VerifyVCache(adp, &treq);
    if (code) goto done;

    /** If the volume is read-only, return error without making an RPC to the
      * fileserver
      */
    if ( adp->states & CRO ) {
        code = EROFS;
	goto done;
    }

    tdc	= afs_GetDCache(adp, 0,	&treq, &offset,	&len, 1);  /* test for error below */
    ObtainWriteLock(&adp->lock,145);
    do {
	tc = afs_Conn(&adp->fid, &treq, SHARED_LOCK);
	if (tc) {
          XSTATS_START_TIME(AFS_STATS_FS_RPCIDX_LINK);
#ifdef RX_ENABLE_LOCKS
	  AFS_GUNLOCK();
#endif /* RX_ENABLE_LOCKS */
	    code = RXAFS_Link(tc->id, (struct AFSFid *) &adp->fid.Fid, aname,
			      (struct AFSFid *) &avc->fid.Fid, &OutFidStatus,
			      &OutDirStatus, &tsync);
#ifdef RX_ENABLE_LOCKS
	  AFS_GLOCK();
#endif /* RX_ENABLE_LOCKS */
          XSTATS_END_TIME;

	}
	else code = -1;
    } while
      (afs_Analyze(tc, code, &adp->fid, &treq,
		   AFS_STATS_FS_RPCIDX_LINK, SHARED_LOCK, (struct cell *)0));

    if (code) {
	if (tdc) afs_PutDCache(tdc);
	if (code < 0) {
	  ObtainWriteLock(&afs_xcbhash, 492);
	  afs_DequeueCallback(adp);
	  adp->states &= ~CStatd;
	  ReleaseWriteLock(&afs_xcbhash);
	  osi_dnlc_purgedp(adp);
	}
	ReleaseWriteLock(&adp->lock);
	goto done;
    }
    if (afs_LocalHero(adp, tdc, &OutDirStatus, 1)) {
	/* we can do it locally */
	code = afs_dir_Create(&tdc->f.inode, aname, &avc->fid.Fid);
	if (code) {
	    ZapDCE(tdc);	/* surprise error -- invalid value */
	    DZap(&tdc->f.inode);
	}
    }
    if (tdc) {
	afs_PutDCache(tdc);	/* drop ref count */
    }
    ReleaseWriteLock(&adp->lock);
    ObtainWriteLock(&avc->lock,146);    /* correct link count */

    /* we could lock both dir and file; since we get the new fid
     * status back, you'd think we could put it in the cache status
     * entry at that point.  Note that if we don't lock the file over
     * the rpc call, we have no guarantee that the status info
     * returned in ustat is the most recent to store in the file's
     * cache entry */

    ObtainWriteLock(&afs_xcbhash, 493);
    afs_DequeueCallback(avc);
    avc->states	&= ~CStatd;	/* don't really know new link count */
    ReleaseWriteLock(&afs_xcbhash);
    if (avc->fid.Fid.Vnode & 1 || (vType(avc) == VDIR))
	osi_dnlc_purgedp(avc);
    ReleaseWriteLock(&avc->lock);
    code = 0;
done:
#ifdef	AFS_OSF_ENV
    afs_PutVCache(adp, WRITE_LOCK);
#endif	/* AFS_OSF_ENV */
    return afs_CheckCode(code, &treq);
}