/*
 * 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 <afsconfig.h>
#include "../afs/param.h"

RCSID("$Header: /afs/sipb/project/openafs/debian/cvs/openafs/src/afs/DARWIN/osi_vm.c,v 1.1.1.5 2002/05/10 23:43:37 hartmans Exp $");

#include "../afs/sysincludes.h" /* Standard vendor system headers */
#include "../afs/afsincludes.h" /* Afs-based standard headers */
#include "../afs/afs_stats.h"  /* statistics */
#include <sys/ubc.h>

/* Try to discard pages, in order to recycle a vcache entry.
 *
 * We also make some sanity checks:  ref count, open count, held locks.
 *
 * We also do some non-VM-related chores, such as releasing the cred pointer
 * (for AIX and Solaris) and releasing the gnode (for AIX).
 *
 * Locking:  afs_xvcache lock is held.  If it is dropped and re-acquired,
 *   *slept should be set to warn the caller.
 *
 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
 * is not dropped and re-acquired for any platform.  It may be that *slept is
 * therefore obsolescent.
 *
 * OSF/1 Locking:  VN_LOCK has been called.
 */
int
osi_VM_FlushVCache(avc, slept)
    struct vcache *avc;
    int *slept;
{
    struct vnode *vp=AFSTOV(avc);
#ifdef AFS_DARWIN14_ENV
    if (UBCINFOEXISTS(vp))
	return EBUSY;
#endif
    if (avc->vrefCount)
	return EBUSY;

    if (avc->opens)
	return EBUSY;

    /* if a lock is held, give up */
    if (CheckLock(&avc->lock) || afs_CheckBozonLock(&avc->pvnLock))
	return EBUSY;

    AFS_GUNLOCK();
    cache_purge(vp);
#ifndef AFS_DARWIN14_ENV
    if (UBCINFOEXISTS(vp))
	{
                ubc_clean(vp, 1);
                ubc_uncache(vp);
                ubc_release(vp);
	        ubc_info_free(vp);
	}
#endif

    AFS_GLOCK();

    return 0;
}


/* Try to store pages to cache, in order to store a file back to the server.
 *
 * Locking:  the vcache entry's lock is held.  It will usually be dropped and
 * re-obtained.
 */
void
osi_VM_StoreAllSegments(avc)
    struct vcache *avc;
{
    struct vnode *vp=AFSTOV(avc);
    ReleaseWriteLock(&avc->lock);
    AFS_GUNLOCK();
    if (UBCINFOEXISTS(vp)) {
	ubc_pushdirty(vp);
    }
    AFS_GLOCK();
    ObtainWriteLock(&avc->lock,94);
}

/* Try to invalidate pages, for "fs flush" or "fs flushv"; or
 * try to free pages, when deleting a file.
 *
 * Locking:  the vcache entry's lock is held.  It may be dropped and 
 * re-obtained.
 *
 * Since we drop and re-obtain the lock, we can't guarantee that there won't
 * be some pages around when we return, newly created by concurrent activity.
 */
void
osi_VM_TryToSmush(avc, acred, sync)
    struct vcache *avc;
    struct AFS_UCRED *acred;
    int sync;
{
    struct vnode *vp=AFSTOV(avc);
    void *object;
    kern_return_t kret;
    off_t size, lastpg;
    
    ReleaseWriteLock(&avc->lock);
    AFS_GUNLOCK();
    if (UBCINFOEXISTS(vp))  {
        size=ubc_getsize(vp);
        kret=ubc_invalidate(vp,0,size); 
        if (kret != 1) /* should be KERN_SUCCESS */
            printf("TryToSmush: invalidate failed (error = %d)\n", kret);
    }
    AFS_GLOCK();
    ObtainWriteLock(&avc->lock,59);
}

/* Purge VM for a file when its callback is revoked.
 *
 * Locking:  No lock is held, not even the global lock.
 */
/* XXX this seems to not be referenced anywhere. *somebody* ought to be calling
   this, and also making sure that ubc's idea of the filesize is right more
   often */
void
osi_VM_FlushPages(avc, credp)
    struct vcache *avc;
    struct AFS_UCRED *credp;
{
    struct vnode *vp=AFSTOV(avc);
    void *object;
    kern_return_t kret;
    off_t size;
    if (UBCINFOEXISTS(vp))  {
        size=ubc_getsize(vp);
        kret=ubc_invalidate(vp,0,size);
        if (kret != 1) /* Should be KERN_SUCCESS */
          printf("VMFlushPages: invalidate failed (error = %d)\n", kret);
        /* XXX what about when not CStatd */
        if (avc->states & CStatd && size != avc->m.Length) 
            ubc_setsize(vp, avc->m.Length);
    }
}

/* Purge pages beyond end-of-file, when truncating a file.
 *
 * Locking:  no lock is held, not even the global lock.
 * activeV is raised.  This is supposed to block pageins, but at present
 * it only works on Solaris.
 */
void
osi_VM_Truncate(avc, alen, acred)
    struct vcache *avc;
    int alen;
    struct AFS_UCRED *acred;
{
    struct vnode *vp=AFSTOV(avc);
    if (UBCINFOEXISTS(vp))  {
	ubc_setsize(vp, alen);
    }
}

extern struct  AFS_UCRED afs_osi_cred;
extern afs_rwlock_t afs_xvcache;
/* vnreclaim and vinactive are probably not aggressive enough to keep
   enough afs vcaches free, so we try to do some of it ourselves */
/* XXX there's probably not nearly enough locking here */
void osi_VM_TryReclaim(avc, slept)
     struct vcache *avc;
     int *slept;
{
    struct proc *p=current_proc();
    struct vnode *vp=AFSTOV(avc);
    void *obj;

    if (slept)
       *slept=0;
    VN_HOLD(vp); /* remove from inactive list */
    if (!simple_lock_try(&vp->v_interlock)) {
        AFS_RELE(vp);
        return;
    }
    if (!UBCINFOEXISTS(vp) || vp->v_count != 2) {
        simple_unlock(&vp->v_interlock);
        AFS_RELE(vp);
        return;
    }
#ifdef AFS_DARWIN14_ENV
    if (vp->v_ubcinfo->ui_refcount > 1) {
        simple_unlock(&vp->v_interlock);
        AFS_RELE(vp);
        return;
    }
#else
    if (vp->v_ubcinfo->ui_holdcnt) {
        simple_unlock(&vp->v_interlock);
        AFS_RELE(vp);
        return;
    }
#endif
    if (slept && ubc_issetflags(vp, UI_WASMAPPED)) {
       /* We can't possibly release this in time for this NewVCache to get it */
        simple_unlock(&vp->v_interlock);
        AFS_RELE(vp);
        return;
    }

    vp->v_usecount--; /* we want the usecount to be 1 */

    if (slept) {
        ReleaseWriteLock(&afs_xvcache);
        *slept=1;
    } else
        ReleaseReadLock(&afs_xvcache);
    AFS_GUNLOCK();
    obj=0;
    if (ubc_issetflags(vp, UI_WASMAPPED)) {
        simple_unlock(&vp->v_interlock);
#ifdef  AFS_DARWIN14_ENV
        ubc_release_named(vp);
#else
        ubc_release(vp);
#endif
        if (ubc_issetflags(vp, UI_HASOBJREF))
            printf("ubc_release didn't release the reference?!\n");
    } else if (!vn_lock(vp, LK_EXCLUSIVE|LK_INTERLOCK,current_proc())) {
#ifdef AFS_DARWIN14_ENV
        obj = ubc_getobject(vp,UBC_HOLDOBJECT);
#else
#ifdef AFS_DARWIN13_ENV
        obj = ubc_getobject(vp,(UBC_NOREACTIVATE|UBC_HOLDOBJECT));
#else
        obj = ubc_getobject(vp);
#endif
#endif
        (void)ubc_clean(vp, 1);
        vinvalbuf(vp, V_SAVE, &afs_osi_cred, p, 0, 0);
        if (vp->v_usecount == 1)
           VOP_INACTIVE(vp, p);
        else
           VOP_UNLOCK(vp, 0, p);
        if (obj) {
        if (ISSET(vp->v_flag, VTERMINATE))
            panic("afs_vnreclaim: already teminating");
        SET(vp->v_flag, VTERMINATE);
        memory_object_destroy(obj, 0);
        while (ISSET(vp->v_flag, VTERMINATE)) {
              SET(vp->v_flag, VTERMWANT);
              tsleep((caddr_t)&vp->v_ubcinfo, PINOD, "afs_vnreclaim", 0);
        }
        }
   } else {
        if (simple_lock_try(&vp->v_interlock))
            panic("afs_vnreclaim: slept, but did no work :(");
        if (UBCINFOEXISTS(vp) && vp->v_count == 1) {
           vp->v_usecount++;
           simple_unlock(&vp->v_interlock);
           VN_RELE(vp);
        } else 
           simple_unlock(&vp->v_interlock);
   }
   AFS_GLOCK();
   if (slept)
      ObtainWriteLock(&afs_xvcache,175);
   else
      ObtainReadLock(&afs_xvcache);
}

void osi_VM_NukePages(struct vnode *vp, off_t offset, off_t size) {

    void *object;
    struct vcache *avc = VTOAFS(vp);

#ifdef AFS_DARWIN14_ENV
    offset=trunc_page(offset);
    size=round_page(size+1);
    while (size) {
        ubc_page_op(vp, (vm_offset_t)offset, 
                              UPL_POP_SET | UPL_POP_BUSY | UPL_POP_DUMP,
                              0, 0);
        size-=PAGE_SIZE;
        offset+=PAGE_SIZE;
    }
#else
    object=NULL;
#ifdef AFS_DARWIN13_ENV
    if (UBCINFOEXISTS(vp))
        object = ubc_getobject(vp, UBC_NOREACTIVATE);
#else
    if (UBCINFOEXISTS(vp))
        object = ubc_getobject(vp);
#endif
    if (!object)
        return;

    offset=trunc_page(offset);
    size=round_page(size+1);

#ifdef AFS_DARWIN13_ENV
    while (size) {
        memory_object_page_op(object, (vm_offset_t)offset, 
                              UPL_POP_SET | UPL_POP_BUSY | UPL_POP_DUMP,
                              0, 0);
        size-=PAGE_SIZE;
        offset+=PAGE_SIZE;
    }
#else 
    /* This is all we can do, and it's not enough. sucks to be us */
    ubc_setsize(vp, offset);
    size=(offset + size > avc->m.Length) ? offset + size : avc->m.Length;
    ubc_setsize(vp, size);
#endif
#endif

}
int osi_VM_Setup(struct vcache *avc) {
   int error;
   struct vnode *vp=AFSTOV(avc);

   if (UBCISVALID(vp) && (avc->states & CStatd)) {
      if (!UBCINFOEXISTS(vp) && !ISSET(vp->v_flag, VTERMINATE)) {
         osi_vnhold(avc,0);  
         AFS_GUNLOCK();
         if ((error=ubc_info_init(&avc->v)))  {
             AFS_GLOCK();
             AFS_RELE(avc);
             return error;
         }
#ifndef AFS_DARWIN14_ENV
         simple_lock(&avc->v.v_interlock);
         if (!ubc_issetflags(&avc->v, UI_HASOBJREF))
#ifdef AFS_DARWIN13_ENV
            if (ubc_getobject(&avc->v, (UBC_NOREACTIVATE|UBC_HOLDOBJECT)))
                   panic("VM_Setup: null object");
#else
            (void)_ubc_getobject(&avc->v, 1); /* return value not used */
#endif
         simple_unlock(&avc->v.v_interlock);
#endif
         AFS_GLOCK();
         AFS_RELE(avc);
      }
      if (UBCINFOEXISTS(&avc->v))
          ubc_setsize(&avc->v, avc->m.Length);
   }
   return 0;
}
