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
11 /* osi_vm.c implements:
13 * osi_VM_FlushVCache(avc, slept)
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)
21 #include <afsconfig.h>
22 #include "afs/param.h"
24 #include <sys/param.h>
25 #include <sys/vnode.h>
27 vgonel(struct vnode *vp, struct thread *td);
33 #include "afs/sysincludes.h" /* Standard vendor system headers */
34 #include "afsincludes.h" /* Afs-based standard headers */
35 #include "afs/afs_stats.h" /* statistics */
36 #include <vm/vm_object.h>
37 #include <vm/vm_map.h>
42 * FreeBSD implementation notes:
43 * Most of these operations require us to frob vm_objects. Most
44 * functions require that the object be locked (with VM_OBJECT_LOCK)
45 * on entry and leave it locked on exit. In order to get the
46 * vm_object itself we call VOP_GETVOBJECT on the vnode; the
47 * locking protocol requires that we do so with the heavy vnode lock
48 * held and the vnode interlock unlocked, and it returns the same
51 * The locking protocol for vnodes is defined in
52 * kern/vnode_if.src and sys/vnode.h; the locking is still a work in
53 * progress, so some fields are (as of 5.1) still protected by Giant
54 * rather than an explicit lock.
58 #define VOP_GETVOBJECT(vp, objp) (*(objp) = (vp)->v_object)
61 #if defined(AFS_FBSD80_ENV)
62 #define lock_vnode(v) vn_lock((v), LK_EXCLUSIVE | LK_RETRY)
63 #define unlock_vnode(v) VOP_UNLOCK((v), 0)
64 #elif defined(AFS_FBSD50_ENV)
65 #define lock_vnode(v) vn_lock((v), LK_EXCLUSIVE | LK_RETRY, curthread)
66 #define unlock_vnode(v) VOP_UNLOCK((v), 0, curthread)
68 #define lock_vnode(v) vn_lock((v), LK_EXCLUSIVE | LK_RETRY, curproc)
69 #define unlock_vnode(v) VOP_UNLOCK((v), 0, curproc)
70 /* need splvm() protection? */
71 #define VM_OBJECT_LOCK(o)
72 #define VM_OBJECT_UNLOCK(o)
75 /* Try to discard pages, in order to recycle a vcache entry.
77 * We also make some sanity checks: ref count, open count, held locks.
79 * We also do some non-VM-related chores, such as releasing the cred pointer
80 * (for AIX and Solaris) and releasing the gnode (for AIX).
82 * Locking: afs_xvcache lock is held. If it is dropped and re-acquired,
83 * *slept should be set to warn the caller.
85 * Formerly, afs_xvcache was dropped and re-acquired for Solaris, but now it
86 * is not dropped and re-acquired for any platform. It may be that *slept is
87 * therefore obsolescent.
89 * OSF/1 Locking: VN_LOCK has been called.
90 * XXX - should FreeBSD have done this, too? Certainly looks like it.
91 * Maybe better to just call vnode_pager_setsize()?
94 osi_VM_FlushVCache(struct vcache *avc, int *slept)
96 struct vm_object *obj;
98 if (VREFCOUNT(avc) > 1)
104 /* if a lock is held, give up */
105 if (CheckLock(&avc->lock))
112 #ifndef AFS_FBSD70_ENV
115 if (VOP_GETVOBJECT(vp, &obj) == 0) {
117 vm_object_page_remove(obj, 0, 0, FALSE);
119 if (obj->ref_count == 0) {
120 simple_lock(&vp->v_interlock);
121 vgonel(vp, curthread);
126 VM_OBJECT_UNLOCK(obj);
128 #ifndef AFS_FBSD70_ENV
136 /* Try to store pages to cache, in order to store a file back to the server.
138 * Locking: the vcache entry's lock is held. It will usually be dropped and
142 osi_VM_StoreAllSegments(struct vcache *avc)
145 struct vm_object *obj;
148 ReleaseWriteLock(&avc->lock);
154 * I don't understand this. Why not just call vm_object_page_clean()
155 * and be done with it? I particularly don't understand why we're calling
156 * vget() here. Is there some reason to believe that the vnode might
157 * be being recycled at this point? I don't think there's any need for
158 * this loop, either -- if we keep the vnode locked all the time,
159 * that and the object lock will prevent any new pages from appearing.
160 * The loop is what causes the race condition. -GAW
164 #ifdef AFS_FBSD80_ENV
167 if (VOP_GETVOBJECT(vp, &obj) == 0 && (obj->flags & OBJ_MIGHTBEDIRTY)) {
168 #ifdef AFS_FBSD80_ENV
171 #ifdef AFS_FBSD50_ENV
172 if (!vget(vp, LK_EXCLUSIVE | LK_RETRY, curthread)) {
174 if (!vget(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ, curproc)) {
176 if (VOP_GETVOBJECT(vp, &obj) == 0) {
178 vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
179 VM_OBJECT_UNLOCK(obj);
185 #ifdef AFS_FBSD80_ENV
189 } while (anyio && (--tries > 0));
191 ObtainWriteLock(&avc->lock, 94);
194 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
195 * try to free pages, when deleting a file.
197 * Locking: the vcache entry's lock is held. It may be dropped and
200 * Since we drop and re-obtain the lock, we can't guarantee that there won't
201 * be some pages around when we return, newly created by concurrent activity.
204 osi_VM_TryToSmush(struct vcache *avc, struct AFS_UCRED *acred, int sync)
207 struct vm_object *obj;
208 int anyio, tries, code;
214 if (vp->v_iflag & VI_DOOMED) {
219 if (vp->v_bufobj.bo_object != NULL) {
220 VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
222 * Do we really want OBJPC_SYNC? OBJPC_INVAL would be
223 * faster, if invalidation is really what we are being
224 * asked to do. (It would make more sense, too, since
225 * otherwise this function is practically identical to
226 * osi_VM_StoreAllSegments().) -GAW
230 * Dunno. We no longer resemble osi_VM_StoreAllSegments,
231 * though maybe that's wrong, now. And OBJPC_SYNC is the
232 * common thing in 70 file systems, it seems. Matt.
235 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
236 VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
240 code = vinvalbuf(vp, V_SAVE, curthread, PCATCH, 0);
241 while (code && (tries > 0)) {
242 code = vinvalbuf(vp, V_SAVE, curthread, PCATCH, 0);
248 /* Purge VM for a file when its callback is revoked.
250 * Locking: No lock is held, not even the global lock.
253 osi_VM_FlushPages(struct vcache *avc, struct AFS_UCRED *credp)
256 struct vm_object *obj;
259 ASSERT_VOP_LOCKED(vp, __func__);
260 if (VOP_GETVOBJECT(vp, &obj) == 0) {
262 vm_object_page_remove(obj, 0, 0, FALSE);
263 VM_OBJECT_UNLOCK(obj);
265 /*vinvalbuf(AFSTOV(avc),0, NOCRED, curproc, 0,0); */
268 /* Purge pages beyond end-of-file, when truncating a file.
270 * Locking: no lock is held, not even the global lock.
271 * activeV is raised. This is supposed to block pageins, but at present
272 * it only works on Solaris.
275 osi_VM_Truncate(struct vcache *avc, int alen, struct AFS_UCRED *acred)
277 vnode_pager_setsize(AFSTOV(avc), alen);