src/afs/SOLARIS/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 #include <afsconfig.h>
  11 #include "afs/param.h"
  12
  13
  14 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  15 #include "afsincludes.h"        /* Afs-based standard headers */
  16 #include "afs/afs_stats.h"      /* statistics */
  17 #include "afs/nfsclient.h"
  18
  19 /* This file contains Solaris VM-related code for the cache manager. */
  20
  21 #include <sys/mman.h>
  22 #include <vm/hat.h>
  23 #include <vm/as.h>
  24 #include <vm/page.h>
  25 #include <vm/pvn.h>
  26 #include <vm/seg.h>
  27 #include <vm/seg_map.h>
  28 #include <vm/seg_vn.h>
  29 #include <vm/rm.h>
  30 #include <sys/modctl.h>
  31 #include <sys/syscall.h>
  32 #include <sys/debug.h>
  33 #include <sys/fs_subr.h>
  34
  35 /* Try to invalidate pages, in order to recycle a dcache entry.
  36  *
  37  * This function only exists for Solaris.  For other platforms, it's OK to
  38  * recycle a dcache entry without invalidating pages, because the strategy
  39  * function can call afs_GetDCache().
  40  *
  41  * Locking:  only the global lock is held on entry.
  42  */
  43 int
  44 osi_VM_GetDownD(struct vcache *avc, struct dcache *adc)
  45 {
  46     int code;
  47
  48     AFS_GUNLOCK();
  49     code =
  50         afs_putpage(AFSTOV(avc), (offset_t) AFS_CHUNKTOBASE(adc->f.chunk),
  51                     AFS_CHUNKTOSIZE(adc->f.chunk), B_INVAL, CRED());
  52     AFS_GLOCK();
  53
  54     return code;
  55 }
  56
  57 /* Does this dcache conflict with a multiPage request for this vcache?
  58  *
  59  * This function only exists for Solaris. This is used by afs_GetDownD to
  60  * calculate if trying to evict the given dcache may deadlock with an
  61  * in-progress afs_getpage call that is trying to get more than one page at
  62  * once. See afs_getpage for details. We return 0 if we do NOT conflict,
  63  * nonzero otherwise. If we return nonzero, we should NOT try to evict the
  64  * given dcache entry from the cache.
  65  *
  66  * Locking: tvc->vlock is write-locked on entry (and GLOCK is held)
  67  */
  68 int
  69 osi_VM_MultiPageConflict(struct vcache *avc, struct dcache *adc)
  70 {
  71     struct multiPage_range *range;
  72     for (range = (struct multiPage_range *)avc->multiPage.next;
  73          range != &avc->multiPage;
  74          range = (struct multiPage_range *)QNext(&range->q)) {
  75
  76         if (adc->f.chunk >= AFS_CHUNK(range->off) &&
  77             adc->f.chunk <= AFS_CHUNK(range->off + range->len - 1)) {
  78             return 1;
  79         }
  80     }
  81
  82     return 0;
  83 }
  84
  85 /* Try to discard pages, in order to recycle a vcache entry.
  86  *
  87  * We also make some sanity checks:  ref count, open count, held locks.
  88  *
  89  * We also do some non-VM-related chores, such as releasing the cred pointer
  90  * (for AIX and Solaris) and releasing the gnode (for AIX).
  91  *
  92  * Locking:  afs_xvcache lock is held. It must not be dropped.
  93  */
  94 int
  95 osi_VM_FlushVCache(struct vcache *avc)
  96 {
  97     if (avc->vrefCount != 0)
  98         return EBUSY;
  99
 100     if (avc->opens)
 101         return EBUSY;
 102
 103     /* if a lock is held, give up */
 104     if (CheckLock(&avc->lock))
 105         return EBUSY;
 106
 107     AFS_GUNLOCK();
 108     pvn_vplist_dirty(AFSTOV(avc), 0, NULL, B_TRUNC | B_INVAL, CRED());
 109     AFS_GLOCK();
 110
 111     /* Might as well make the obvious check */
 112     if (AFSTOV(avc)->v_pages)
 113         return EBUSY;           /* should be all gone still */
 114
 115     rw_destroy(&avc->rwlock);
 116     if (avc->credp) {
 117         crfree(avc->credp);
 118         avc->credp = NULL;
 119     }
 120
 121
 122     return 0;
 123 }
 124
 125 /* Try to store pages to cache, in order to store a file back to the server.
 126  *
 127  * Locking:  the vcache entry's lock is held.  It will usually be dropped and
 128  * re-obtained.
 129  */
 130 void
 131 osi_VM_StoreAllSegments(struct vcache *avc)
 132 {
 133     AFS_GUNLOCK();
 134     (void)pvn_vplist_dirty(AFSTOV(avc), (u_offset_t) 0, afs_putapage, 0,
 135                            CRED());
 136     AFS_GLOCK();
 137 }
 138
 139 /* Try to invalidate pages, for "fs flush" or "fs flushv"; or
 140  * try to free pages, when deleting a file.
 141  *
 142  * Locking:  the vcache entry's lock is held.  It may be dropped and
 143  * re-obtained.
 144  */
 145 void
 146 osi_VM_TryToSmush(struct vcache *avc, afs_ucred_t *acred, int sync)
 147 {
 148     AFS_GUNLOCK();
 149     (void)pvn_vplist_dirty(AFSTOV(avc), (u_offset_t) 0, afs_putapage,
 150                            (sync ? B_INVAL : B_FREE), acred);
 151     AFS_GLOCK();
 152 }
 153
 154 /* Purge VM for a file when its callback is revoked.
 155  *
 156  * Locking:  No lock is held, not even the global lock.
 157  */
 158 void
 159 osi_VM_FlushPages(struct vcache *avc, afs_ucred_t *credp)
 160 {
 161     extern int afs_pvn_vptrunc;
 162
 163     afs_pvn_vptrunc++;
 164     (void)afs_putpage(AFSTOV(avc), (offset_t) 0, 0, B_TRUNC | B_INVAL, credp);
 165 }
 166
 167 /* Zero no-longer-used part of last page, when truncating a file
 168  *
 169  * This function only exists for Solaris.  Other platforms do not support it.
 170  *
 171  * Locking:  the vcache entry lock is held.  It is released and re-obtained.
 172  * The caller will raise activeV (to prevent pageins), but this function must
 173  * be called first, since it causes a pagein.
 174  */
 175 void
 176 osi_VM_PreTruncate(struct vcache *avc, int alen, afs_ucred_t *acred)
 177 {
 178     page_t *pp;
 179     int pageOffset = (alen & PAGEOFFSET);
 180
 181     if (pageOffset == 0) {
 182         return;
 183     }
 184
 185     ReleaseWriteLock(&avc->lock);
 186     AFS_GUNLOCK();
 187     pp = page_lookup(AFSTOV(avc), alen - pageOffset, SE_EXCL);
 188     if (pp) {
 189         pagezero(pp, pageOffset, PAGESIZE - pageOffset);
 190         page_unlock(pp);
 191     }
 192     AFS_GLOCK();
 193     ObtainWriteLock(&avc->lock, 563);
 194 }
 195
 196 /* Purge pages beyond end-of-file, when truncating a file.
 197  *
 198  * Locking:  no lock is held, not even the global lock.
 199  * Pageins are blocked (activeV is raised).
 200  */
 201 void
 202 osi_VM_Truncate(struct vcache *avc, int alen, afs_ucred_t *acred)
 203 {
 204     /*
 205      * It's OK to specify afs_putapage here, even though we aren't holding
 206      * the vcache entry lock, because it isn't going to get called.
 207      */
 208     pvn_vplist_dirty(AFSTOV(avc), alen, afs_putapage, B_TRUNC | B_INVAL,
 209                      acred);
 210 }