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 "../afs/param.h" /* Should be always first */
11 #include "../afs/sysincludes.h" /* Standard vendor system headers */
12 #include "../afs/afsincludes.h" /* Afs-based standard headers */
13 #include "../afs/afs_stats.h" /* statistics */
14 #include <vm/vm_ubc.h>
17 /* Try to discard pages, in order to recycle a vcache entry.
19 * We also make some sanity checks: ref count, open count, held locks.
21 * We also do some non-VM-related chores, such as releasing the cred pointer
22 * (for AIX and Solaris) and releasing the gnode (for AIX).
24 * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
25 * *slept should be set to warn the caller.
27 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
28 * is not dropped and re-acquired for any platform. It may be that *slept is
29 * therefore obsolescent.
31 * OSF/1 Locking: VN_LOCK has been called.
34 osi_VM_FlushVCache(avc, slept)
38 if (avc->vrefCount > 1)
44 /* if a lock is held, give up */
45 if (CheckLock(&avc->lock) || afs_CheckBozonLock(&avc->pvnLock))
49 ubc_invalidate(((struct vnode *)avc)->v_object, 0, 0, B_INVAL);
56 * osi_ubc_flush_dirty_and_wait -- ensure all dirty pages cleaned
58 * Alpha OSF/1 doesn't make it easy to wait for all dirty pages to be cleaned.
59 * NFS tries to do this by calling waitforio(), which waits for v_numoutput
60 * to go to zero. But that isn't good enough, because afs_putpage() doesn't
61 * increment v_numoutput until it has obtained the vcache entry lock. Suppose
62 * that Process A, trying to flush a page, is waiting for that lock, and
63 * Process B tries to close the file. Process B calls waitforio() which thinks
64 * that everything is cool because v_numoutput is still zero. Process B then
65 * proceeds to call afs_StoreAllSegments(). Finally when B is finished, A gets
66 * to proceed and flush its page. But then it's too late because the file is
69 * (I suspect that waitforio() is not adequate for NFS, just as it isn't
70 * adequate for us. But that's not my problem.)
72 * The only way we can be sure that there are no more dirty pages is if there
73 * are no more pages with pg_busy set. We look for them on the cleanpl.
75 * For some reason, ubc_flush_dirty() only looks at the dirtypl, not the
76 * dirtywpl. I don't know why this is good enough, but I assume it is. By
77 * the same token, I only look for busy pages on the cleanpl, not the cleanwpl.
79 * Called with the global lock NOT held.
82 osi_ubc_flush_dirty_and_wait(vp, flags)
90 struct vm_ubc_object* vop;
91 vop = (struct vm_ubc_object*)(vp->v_object);
92 ubc_flush_dirty(vop, flags);
96 /* shouldn't happen, but who knows */
100 if (vop->vu_cleanpl) {
101 for (first = 1, pp = vop->vu_cleanpl;
102 first || pp != vop->vu_cleanpl;
103 first = 0, pp = pp->pg_onext) {
107 assert_wait_mesg((vm_offset_t)pp, FALSE, "pg_wait");
108 vm_object_unlock(vop);
116 vm_object_unlock(vop);
120 /* Try to store pages to cache, in order to store a file back to the server.
122 * Locking: the vcache entry's lock is held. It will usually be dropped and
126 osi_VM_StoreAllSegments(avc)
129 ReleaseWriteLock(&avc->lock);
131 osi_ubc_flush_dirty_and_wait((struct vnode *)avc, 0);
133 ObtainWriteLock(&avc->lock,94);
136 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
137 * try to free pages, when deleting a file.
139 * Locking: the vcache entry's lock is held. It may be dropped and
142 * Since we drop and re-obtain the lock, we can't guarantee that there won't
143 * be some pages around when we return, newly created by concurrent activity.
146 osi_VM_TryToSmush(avc, acred, sync)
148 struct AFS_UCRED *acred;
151 ReleaseWriteLock(&avc->lock);
153 osi_ubc_flush_dirty_and_wait((struct vnode *)avc, 0);
154 ubc_invalidate(((struct vnode *)avc)->v_object, 0, 0, B_INVAL);
156 ObtainWriteLock(&avc->lock,59);
159 /* Purge VM for a file when its callback is revoked.
161 * Locking: No lock is held, not even the global lock.
164 osi_VM_FlushPages(avc, credp)
166 struct AFS_UCRED *credp;
168 ubc_flush_dirty(((struct vnode *)avc)->v_object, 0);
169 ubc_invalidate(((struct vnode *)avc)->v_object, 0, 0, B_INVAL);
172 /* Purge pages beyond end-of-file, when truncating a file.
174 * Locking: no lock is held, not even the global lock.
175 * activeV is raised. This is supposed to block pageins, but at present
176 * it only works on Solaris.
179 osi_VM_Truncate(avc, alen, acred)
182 struct AFS_UCRED *acred;
184 ubc_invalidate(((struct vnode *)avc)->v_object, alen,
185 MAXINT - alen, B_INVAL);