2 * Copyright 2000, International Business Machines Corporation and others.
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
10 #include <afsconfig.h>
11 #include "afs/param.h"
14 #include "afs/sysincludes.h" /* Standard vendor system headers */
15 #include "afsincludes.h" /* Afs-based standard headers */
16 #include "afs/afs_stats.h" /* statistics */
18 /* Try to discard pages, in order to recycle a vcache entry.
20 * We also make some sanity checks: ref count, open count, held locks.
22 * We also do some non-VM-related chores, such as releasing the cred pointer
23 * (for AIX and Solaris) and releasing the gnode (for AIX).
25 * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
26 * *slept should be set to warn the caller.
28 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
29 * is not dropped and re-acquired for any platform. It may be that *slept is
30 * therefore obsolescent.
33 osi_VM_FlushVCache(struct vcache *avc, int *slept)
35 if (avc->vrefCount != 0)
41 /* Just in case someone is still referring to the vnode we
42 * give up trying to get rid of this guy */
43 if (avc->vrefCount || CheckLock(&avc->lock) || LockWaiters(&avc->lock))
48 vms_delete(avc->segid);
50 avc->segid = avc->vmh = NULL;
58 /* Free the alloced gnode that was accompanying the vcache's vnode */
59 aix_gnode_rele(AFSTOV(avc));
64 /* Try to store pages to cache, in order to store a file back to the server.
66 * Locking: the vcache entry's lock is held. It will usually be dropped and
70 osi_VM_StoreAllSegments(struct vcache *avc)
74 * The execsOrWriters test is done so that we don't thrash on
75 * the vm_writep call below. We only initiate a pageout of the
76 * dirty vm pages on the last store...
77 * this is strictly a pragmatic decision, and _does_ break the
78 * advertised AFS consistency semantics. Without this hack,
79 * AIX systems panic under heavy load. I consider the current
80 * behavior a bug introduced to hack around a worse bug. XXX
82 * Removed do_writep governing sync'ing behavior.
84 ReleaseWriteLock(&avc->lock); /* XXX */
86 vm_writep(avc->segid, 0, MAXFSIZE / PAGESIZE - 1);
87 vms_iowait(avc->segid);
89 ObtainWriteLock(&avc->lock, 93); /* XXX */
91 * The following is necessary because of the following
92 * asynchronicity: We open a file, write to it and
94 * if CCore flag is set, we clear it and do the extra
95 * decrement ourselves now.
96 * If we're called by the CCore clearer, the CCore flag
97 * will already be clear, so we don't have to worry about
99 * avc was "VN_HELD" and "crheld" when CCore was set in
102 if (avc->f.states & CCore) {
103 avc->f.states &= ~CCore;
105 avc->execsOrWriters--;
106 AFS_RELE(AFSTOV(avc));
107 crfree((struct ucred *)avc->linkData);
108 avc->linkData = NULL;
113 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
114 * try to free pages, when deleting a file.
116 * Locking: the vcache entry's lock is held. It may be dropped and
119 * Since we drop and re-obtain the lock, we can't guarantee that there won't
120 * be some pages around when we return, newly created by concurrent activity.
123 osi_VM_TryToSmush(struct vcache *avc, AFS_UCRED *acred, int sync)
126 ReleaseWriteLock(&avc->lock);
128 vm_flushp(avc->segid, 0, MAXFSIZE / PAGESIZE - 1);
129 vms_iowait(avc->segid); /* XXX Wait?? XXX */
131 ObtainWriteLock(&avc->lock, 60);
135 /* Purge VM for a file when its callback is revoked.
137 * Locking: No lock is held, not even the global lock.
140 osi_VM_FlushPages(struct vcache *avc, AFS_UCRED *credp)
143 vm_flushp(avc->segid, 0, MAXFSIZE / PAGESIZE - 1);
145 * XXX We probably don't need to wait but better be safe XXX
147 vms_iowait(avc->segid);
151 /* Purge pages beyond end-of-file, when truncating a file.
153 * Locking: no lock is held, not even the global lock.
154 * activeV is raised. This is supposed to block pageins, but at present
155 * it only works on Solaris.
158 osi_VM_Truncate(struct vcache *avc, int alen, AFS_UCRED *acred)
161 int firstpage = (alen + PAGESIZE - 1) / PAGESIZE;
162 vm_releasep(avc->segid, firstpage, MAXFSIZE / PAGESIZE - firstpage);
163 vms_iowait(avc->segid); /* Do we need this? */