src/afs/OBSD/osi_vm.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10
  11 /* osi_vm.c implements:
  12  *
  13  * osi_VM_FlushVCache(avc)
  14  * osi_ubc_flush_dirty_and_wait(vp, flags)
  15  * osi_VM_StoreAllSegments(avc)
  16  * osi_VM_TryToSmush(avc, acred, sync)
  17  * osi_VM_FlushPages(avc, credp)
  18  * osi_VM_Truncate(avc, alen, acred)
  19  */
  20
  21 #include <afsconfig.h>
  22 #include "afs/param.h"
  23
  24
  25 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  26 #include "afs/afsincludes.h"    /* Afs-based standard headers */
  27 #include "afs/afs_stats.h"      /* statistics */
  28 #include <sys/namei.h>
  29 #include <limits.h>
  30 #include <float.h>
  31
  32 /* Try to discard pages, in order to recycle a vcache entry.
  33  *
  34  * We also make some sanity checks:  ref count, open count, held locks.
  35  *
  36  * We also do some non-VM-related chores, such as releasing the cred pointer
  37  * (for AIX and Solaris) and releasing the gnode (for AIX).
  38  *
  39  * Locking:  afs_xvcache lock is held. It must not be dropped.
  40  *
  41  * OSF/1 Locking:  VN_LOCK has been called.
  42  */
  43 int
  44 osi_VM_FlushVCache(struct vcache *avc)
  45 {
  46     struct vnode *vp = AFSTOV(avc);
  47
  48     if (!vp)
  49         return 0;
  50     AFS_GUNLOCK();
  51
  52     cache_purge(vp);
  53     uvm_vnp_uncache(vp);
  54
  55     AFS_GLOCK();
  56     return 0;
  57 }
  58
  59 /* Try to store pages to cache, in order to store a file back to the server.
  60  *
  61  * Locking:  the vcache entry's lock is held.  It will usually be dropped and
  62  * re-obtained.
  63  *
  64  */
  65 void
  66 osi_VM_StoreAllSegments(struct vcache *avc)
  67 {
  68 }
  69
  70 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
  71  * try to free pages, when deleting a file.
  72  *
  73  * Locking:  the vcache entry's lock is held.  It may be dropped and
  74  * re-obtained.
  75  *
  76  * Since we drop and re-obtain the lock, we can't guarantee that there won't
  77  * be some pages around when we return, newly created by concurrent activity.
  78  */
  79 void
  80 osi_VM_TryToSmush(struct vcache *avc, afs_ucred_t *acred, int sync)
  81 {
  82     ReleaseWriteLock(&avc->lock);
  83     osi_VM_FlushVCache(avc);
  84     ObtainWriteLock(&avc->lock, 59);
  85 }
  86
  87 /* Purge VM for a file when its callback is revoked.
  88  *
  89  * Locking:  No lock is held, not even the global lock.
  90  */
  91 void
  92 osi_VM_FlushPages(struct vcache *avc, afs_ucred_t *credp)
  93 {
  94     struct vnode *vp = AFSTOV(avc);
  95
  96     if (!vp)
  97         return;
  98     cache_purge(vp);
  99     uvm_vnp_uncache(vp);
 100     uvm_vnp_setsize(vp, avc->f.m.Length);
 101 }
 102
 103 /* Purge pages beyond end-of-file, when truncating a file.
 104  *
 105  * Locking:  no lock is held, not even the global lock.
 106  * activeV is raised.  This is supposed to block pageins, but at present
 107  * it only works on Solaris.
 108  */
 109 void
 110 osi_VM_Truncate(struct vcache *avc, int alen, afs_ucred_t *acred)
 111 {
 112     uvm_vnp_setsize(AFSTOV(avc), alen);
 113 }