/* Copyright (C) 1995, 1989, 1998 Transarc Corporation - All rights reserved */
/*
 * (C) COPYRIGHT IBM CORPORATION 1987, 1988
 * LICENSED MATERIALS - PROPERTY OF IBM
 */
/*
 * afs_vnop_strategy.c
 *
 * Implements:
 * afs_ustrategy
 */

#include "../afs/param.h"	/* Should be always first */
#if !defined(AFS_HPUX_ENV) && !defined(AFS_SGI_ENV) && !defined(AFS_LINUX20_ENV)

#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"




#if	defined(AFS_SUN5_ENV) || defined(AFS_OSF_ENV)
afs_ustrategy(abp, credp)
    struct AFS_UCRED *credp;
#else
afs_ustrategy(abp)
#endif
    register struct buf *abp; {
    register afs_int32 code;
    struct uio tuio;
    register struct vcache *tvc = (struct vcache *) abp->b_vp;
    register afs_int32 len = abp->b_bcount;
#if	!defined(AFS_SUN5_ENV) && !defined(AFS_OSF_ENV)
#ifdef	AFS_AIX41_ENV
    struct ucred *credp;
#else
    struct AFS_UCRED *credp = u.u_cred;
#endif
#endif
#if	defined(AFS_SUN_ENV) || defined(AFS_SUN5_ENV)
    int async = abp->b_flags & B_ASYNC;
#endif
    struct iovec tiovec[1];

    AFS_STATCNT(afs_ustrategy);
#ifdef	AFS_AIX41_ENV
    /*
     * So that it won't change while reading it
     */
    ObtainReadLock(&tvc->lock);
    if (tvc->credp) {	
	credp = tvc->credp;
	crhold(credp);
    } else {
	credp = crref();
    }
    ReleaseReadLock(&tvc->lock);
    osi_Assert(credp);
#endif
    if ((abp->b_flags & B_READ) == B_READ) {
	/* read b_bcount bytes into kernel address b_un.b_addr starting
	    at byte DEV_BSIZE * b_blkno.  Bzero anything we can't read,
	    and finally call iodone(abp).  File is in abp->b_vp.  Credentials
	    are from u area??
	*/
	tuio.afsio_iov = tiovec;
	tuio.afsio_iovcnt = 1;
#if	defined(AFS_SUN_ENV) || defined(AFS_ALPHA_ENV) || defined(AFS_SUN5_ENV)
	tuio.afsio_offset = (u_int) dbtob(abp->b_blkno);
#if	defined(AFS_SUN5_ENV)
	tuio._uio_offset._p._u = 0;
#endif
#else
	tuio.afsio_offset = DEV_BSIZE * abp->b_blkno;
#endif
	tuio.afsio_seg = AFS_UIOSYS;
#ifdef AFS_UIOFMODE
	tuio.afsio_fmode = 0;
#endif
	tuio.afsio_resid = abp->b_bcount;
	tiovec[0].iov_base = abp->b_un.b_addr;
	tiovec[0].iov_len = abp->b_bcount;
	/* are user's credentials valid here?  probably, but this
	     sure seems like the wrong things to do. */
#if	defined(AFS_SUN5_ENV)
	code = afs_nlrdwr((struct vcache *) abp->b_vp, &tuio, UIO_READ, 0, credp);
#else
	code = afs_rdwr((struct vcache *) abp->b_vp, &tuio, UIO_READ, 0, credp);
#endif
	if (code == 0) {
	    if (tuio.afsio_resid > 0)
		bzero(abp->b_un.b_addr + abp->b_bcount - tuio.afsio_resid, tuio.afsio_resid);
#ifdef	AFS_AIX32_ENV
	    /*
	     * If we read a block that is past EOF and the user was not storing
	     * to it, go ahead and write protect the page. This way we will detect
	     * storing beyond EOF in the future
	     */
	    if (dbtob(abp->b_blkno) + abp->b_bcount > tvc->m.Length) {
		if ((abp->b_flags & B_PFSTORE) == 0) {
		    AFS_GUNLOCK();
		    vm_protectp(tvc->vmh, dbtob(abp->b_blkno)/PAGESIZE,
				abp->b_bcount/PAGESIZE, RDONLY);
		    AFS_GLOCK();
		}
	    }
#endif
	}
    }
    else {
	tuio.afsio_iov = tiovec;
	tuio.afsio_iovcnt = 1;
#if	defined(AFS_SUN_ENV) || defined(AFS_ALPHA_ENV) || defined(AFS_SUN5_ENV)
	tuio.afsio_offset = (u_int) dbtob(abp->b_blkno);
#ifdef	AFS_SUN5_ENV
	tuio._uio_offset._p._u = 0;
	tuio.uio_limit = u.u_rlimit[RLIMIT_FSIZE].rlim_cur;
#endif
#else
	tuio.afsio_offset = DEV_BSIZE * abp->b_blkno;
#endif
	tuio.afsio_seg = AFS_UIOSYS;
#ifdef AFS_UIOFMODE
	tuio.afsio_fmode = 0;
#endif
#ifdef	AFS_AIX32_ENV	
	/*
	 * XXX It this really right? Ideally we should always write block size multiple
	 * and not any arbitrary size, right? XXX
	 */
	len = MIN(len, tvc->m.Length - dbtob(abp->b_blkno));
#endif
#ifdef	AFS_ALPHA_ENV
	len = MIN(abp->b_bcount, ((struct vcache *)abp->b_vp)->m.Length - dbtob(abp->b_blkno));
#endif	/* AFS_ALPHA_ENV */
	tuio.afsio_resid = len;
	tiovec[0].iov_base = abp->b_un.b_addr;
	tiovec[0].iov_len = len;
	/* are user's credentials valid here?  probably, but this
	     sure seems like the wrong things to do. */
#if	defined(AFS_SUN5_ENV)
	code = afs_nlrdwr((struct vcache *) abp->b_vp, &tuio, UIO_WRITE, 0, credp);
#else
	code = afs_rdwr((struct vcache *) abp->b_vp, &tuio, UIO_WRITE, 0, credp);
#endif
    }
#if	!defined(AFS_AIX32_ENV) && !defined(AFS_SUN5_ENV)
#ifdef AFS_DUX40_ENV
    if (code) {
	abp->b_error = code;
	abp->b_flags |= B_ERROR;
    }
    biodone(abp);
    if (code && !(abp->b_flags & B_READ)) {
	/* prevent ubc from retrying writes */
	AFS_GUNLOCK();
	ubc_invalidate(((struct vnode *)tvc)->v_object,
		       (vm_offset_t)dbtob(abp->b_blkno),
		       PAGE_SIZE, B_INVAL);
	AFS_GLOCK();
    }
#else  /* AFS_DUX40_ENV */
    iodone(abp);
#endif /* AFS_DUX40_ENV */
#endif
#ifdef	AFS_AIX32_ENV
    crfree(credp);
#endif
    afs_Trace3(afs_iclSetp, CM_TRACE_STRATEGYDONE, ICL_TYPE_POINTER, tvc,
	       ICL_TYPE_INT32, code,
	       ICL_TYPE_LONG, tuio.afsio_resid);
    return code;
}

#endif /* !AFS_HPUX_ENV  && !AFS_SGI_ENV && !AFS_LINUX20_ENV */