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"
16 #include "afs/sysincludes.h" /* Standard vendor system headers */
17 #include "afsincludes.h" /* Afs-based standard headers */
18 #include "afs/afs_stats.h" /* afs statistics */
20 #include <sys/adspace.h> /* for vm_att(), vm_det() */
24 osi_Active(register struct vcache *avc)
26 AFS_STATCNT(osi_Active);
27 #if defined(AFS_AIX_ENV) || defined(AFS_OSF_ENV) || defined(AFS_SUN5_ENV) || (AFS_LINUX20_ENV) || defined(AFS_DARWIN_ENV) || defined(AFS_XBSD_ENV)
28 if ((avc->opens > 0) || (avc->states & CMAPPED))
29 return 1; /* XXX: Warning, verify this XXX */
30 #elif defined(AFS_SGI_ENV)
31 if ((avc->opens > 0) || AFS_VN_MAPPED(AFSTOV(avc)))
34 if (avc->opens > 0 || (AFSTOV(avc)->v_flag & VTEXT))
40 /* this call, unlike osi_FlushText, is supposed to discard caches that may
41 contain invalid information if a file is written remotely, but that may
42 contain valid information that needs to be written back if the file is
43 being written locally. It doesn't subsume osi_FlushText, since the latter
44 function may be needed to flush caches that are invalidated by local writes.
46 avc->pvnLock is already held, avc->lock is guaranteed not to be held (by
50 osi_FlushPages(register struct vcache *avc, struct AFS_UCRED *credp)
53 ObtainReadLock(&avc->lock);
54 /* If we've already purged this version, or if we're the ones
55 * writing this version, don't flush it (could lose the
56 * data we're writing). */
57 if ((hcmp((avc->m.DataVersion), (avc->mapDV)) <= 0)
58 || ((avc->execsOrWriters > 0) && afs_DirtyPages(avc))) {
59 ReleaseReadLock(&avc->lock);
62 ReleaseReadLock(&avc->lock);
63 ObtainWriteLock(&avc->lock, 10);
65 if ((hcmp((avc->m.DataVersion), (avc->mapDV)) <= 0)
66 || ((avc->execsOrWriters > 0) && afs_DirtyPages(avc))) {
67 ReleaseWriteLock(&avc->lock);
70 if (hiszero(avc->mapDV)) {
71 hset(avc->mapDV, avc->m.DataVersion);
72 ReleaseWriteLock(&avc->lock);
76 AFS_STATCNT(osi_FlushPages);
77 hset(origDV, avc->m.DataVersion);
78 afs_Trace3(afs_iclSetp, CM_TRACE_FLUSHPAGES, ICL_TYPE_POINTER, avc,
79 ICL_TYPE_INT32, origDV.low, ICL_TYPE_INT32, avc->m.Length);
81 ReleaseWriteLock(&avc->lock);
83 osi_VM_FlushPages(avc, credp);
85 ObtainWriteLock(&avc->lock, 88);
87 /* do this last, and to original version, since stores may occur
88 * while executing above PUTPAGE call */
89 hset(avc->mapDV, origDV);
90 ReleaseWriteLock(&avc->lock);
95 /* This call is supposed to flush all caches that might be invalidated
96 * by either a local write operation or a write operation done on
97 * another client. This call may be called repeatedly on the same
98 * version of a file, even while a file is being written, so it
99 * shouldn't do anything that would discard newly written data before
100 * it is written to the file system. */
103 osi_FlushText_really(register struct vcache *vp)
105 afs_hyper_t fdv; /* version before which we'll flush */
107 AFS_STATCNT(osi_FlushText);
108 /* see if we've already flushed this data version */
109 if (hcmp(vp->m.DataVersion, vp->flushDV) <= 0)
112 MObtainWriteLock(&afs_ftf, 317);
113 hset(fdv, vp->m.DataVersion);
115 /* why this disgusting code below?
116 * xuntext, called by xrele, doesn't notice when it is called
117 * with a freed text object. Sun continually calls xrele or xuntext
118 * without any locking, as long as VTEXT is set on the
119 * corresponding vnode.
120 * But, if the text object is locked when you check the VTEXT
121 * flag, several processes can wait in xuntext, waiting for the
122 * text lock; when the second one finally enters xuntext's
123 * critical region, the text object is already free, but the check
124 * was already done by xuntext's caller.
125 * Even worse, it turns out that xalloc locks the text object
126 * before reading or stating a file via the vnode layer. Thus, we
127 * could end up in getdcache, being asked to bring in a new
128 * version of a file, but the corresponding text object could be
129 * locked. We can't flush the text object without causing
130 * deadlock, so now we just don't try to lock the text object
131 * unless it is guaranteed to work. And we try to flush the text
132 * when we need to a bit more often at the vnode layer. Sun
133 * really blew the vm-cache flushing interface.
136 #if defined (AFS_HPUX_ENV)
137 if (vp->v.v_flag & VTEXT) {
140 if (vp->v.v_flag & VTEXT) { /* still has a text object? */
141 MReleaseWriteLock(&afs_ftf);
147 /* next do the stuff that need not check for deadlock problems */
150 /* finally, record that we've done it */
151 hset(vp->flushDV, fdv);
152 MReleaseWriteLock(&afs_ftf);
155 #endif /* AFS_TEXT_ENV */
157 /* ? is it moderately likely that there are dirty VM pages associated with
160 * Prereqs: avc must be write-locked
162 * System Dependencies: - *must* support each type of system for which
163 * memory mapped files are supported, even if all
164 * it does is return TRUE;
166 * NB: this routine should err on the side of caution for ProcessFS to work
167 * correctly (or at least, not to introduce worse bugs than already exist)
171 osi_VMDirty_p(struct vcache *avc)
175 if (avc->execsOrWriters <= 0)
176 return 0; /* can't be many dirty pages here, I guess */
178 #if defined (AFS_AIX32_ENV)
180 /* because of the level of hardware involvment with VM and all the
181 * warnings about "This routine must be called at VMM interrupt
182 * level", I thought it would be safest to disable interrupts while
183 * looking at the software page fault table. */
185 /* convert vm handle into index into array: I think that stoinio is
186 * always zero... Look into this XXX */
187 #define VMHASH(handle) ( \
188 ( ((handle) & ~vmker.stoinio) \
189 ^ ((((handle) & ~vmker.stoinio) & vmker.stoimask) << vmker.stoihash) \
193 unsigned int pagef, pri, index, next;
195 index = VMHASH(avc->segid);
196 if (scb_valid(index)) { /* could almost be an ASSERT */
198 pri = disable_ints();
199 for (pagef = scb_sidlist(index); pagef >= 0; pagef = next) {
200 next = pft_sidfwd(pagef);
201 if (pft_modbit(pagef)) { /* has page frame been modified? */
211 #endif /* AFS_AIX32_ENV */
213 #if defined (AFS_SUN5_ENV)
214 if (avc->states & CMAPPED) {
216 for (pg = avc->v.v_s.v_Pages; pg; pg = pg->p_vpnext) {
229 * Solaris osi_ReleaseVM should not drop and re-obtain the vcache entry lock.
230 * This leads to bad races when osi_ReleaseVM() is called from
231 * afs_InvalidateAllSegments().
233 * We can do this because Solaris osi_VM_Truncate() doesn't care whether the
234 * vcache entry lock is held or not.
236 * For other platforms, in some cases osi_VM_Truncate() doesn't care, but
237 * there may be cases where it does care. If so, it would be good to fix
238 * them so they don't care. Until then, we assume the worst.
240 * Locking: the vcache entry lock is held. It is dropped and re-obtained.
243 osi_ReleaseVM(struct vcache *avc, struct AFS_UCRED *acred)
247 osi_VM_Truncate(avc, 0, acred);
250 ReleaseWriteLock(&avc->lock);
252 osi_VM_Truncate(avc, 0, acred);
254 ObtainWriteLock(&avc->lock, 80);