afs: Clarify vcache->mvid accesses

[openafs.git] / src / afs / afs_vcache.c

diff --git a/src/afs/afs_vcache.c b/src/afs/afs_vcache.c
index dcdc8d9..1d75f7c 100644 (file)
--- a/src/afs/afs_vcache.c
+++ b/src/afs/afs_vcache.c
@@ -138,12 +138,16 @@ afs_FlushVCache(struct vcache *avc, int *slept)
     afs_int32 i, code;
     struct vcache **uvc, *wvc;
 
+    /* NOTE: We must have nothing drop afs_xvcache until we have removed all
+     * possible references to this vcache. This means all hash tables, queues,
+     * DNLC, etc. */
+
     *slept = 0;
     AFS_STATCNT(afs_FlushVCache);
     afs_Trace2(afs_iclSetp, CM_TRACE_FLUSHV, ICL_TYPE_POINTER, avc,
               ICL_TYPE_INT32, avc->f.states);
 
-    code = osi_VM_FlushVCache(avc, slept);
+    code = osi_VM_FlushVCache(avc);
     if (code)
        goto bad;
 
@@ -180,9 +184,29 @@ afs_FlushVCache(struct vcache *avc, int *slept)
     /* remove entry from the volume hash table */
     QRemove(&avc->vhashq);
 
-    if (avc->mvid)
-       osi_FreeSmallSpace(avc->mvid);
-    avc->mvid = (struct VenusFid *)0;
+#if defined(AFS_LINUX26_ENV)
+    {
+       struct pagewriter *pw, *store;
+       struct list_head tofree;
+
+       INIT_LIST_HEAD(&tofree);
+       spin_lock(&avc->pagewriter_lock);
+       list_for_each_entry_safe(pw, store, &avc->pagewriters, link) {
+           list_del(&pw->link);
+           /* afs_osi_Free may sleep so we need to defer it */
+           list_add_tail(&pw->link, &tofree);
+       }
+       spin_unlock(&avc->pagewriter_lock);
+       list_for_each_entry_safe(pw, store, &tofree, link) {
+           list_del(&pw->link);
+           afs_osi_Free(pw, sizeof(struct pagewriter));
+       }
+    }
+#endif
+
+    if (avc->mvid.target_root)
+       osi_FreeSmallSpace(avc->mvid.target_root);
+    avc->mvid.target_root = NULL;
     if (avc->linkData) {
        afs_osi_Free(avc->linkData, strlen(avc->linkData) + 1);
        avc->linkData = NULL;
@@ -214,6 +238,10 @@ afs_FlushVCache(struct vcache *avc, int *slept)
     else
        osi_dnlc_purgevp(avc);
 
+    /* By this point, the vcache has been removed from all global structures
+     * via which someone could try to use the vcache. It is okay to drop
+     * afs_xvcache at this point (if *slept is set). */
+
     if (!afs_shuttingdown)
        afs_QueueVCB(avc, slept);
 
@@ -680,9 +708,9 @@ afs_PostPopulateVCache(struct vcache *avc, struct VenusFid *afid, int seq)
     /*
      * The proper value for mvstat (for root fids) is setup by the caller.
      */
-    avc->mvstat = 0;
+    avc->mvstat = AFS_MVSTAT_FILE;
     if (afid->Fid.Vnode == 1 && afid->Fid.Unique == 1)
-       avc->mvstat = 2;
+       avc->mvstat = AFS_MVSTAT_ROOT;
 
     if (afs_globalVFS == 0)
        osi_Panic("afs globalvfs");
@@ -810,7 +838,7 @@ afs_PrePopulateVCache(struct vcache *avc, struct VenusFid *afid,
 
     AFS_RWLOCK_INIT(&avc->lock, "vcache lock");
 
-    avc->mvid = NULL;
+    memset(&avc->mvid, 0, sizeof(avc->mvid));
     avc->linkData = NULL;
     avc->cbExpires = 0;
     avc->opens = 0;
@@ -1001,7 +1029,7 @@ afs_FlushActiveVcaches(afs_int32 doflocks)
     XSTATS_DECLS;
     AFS_STATCNT(afs_FlushActiveVcaches);
 
-    code = afs_CreateReq(&treq, NULL);
+    code = afs_CreateReq(&treq, afs_osi_credp);
     if (code) {
        afs_warn("unable to alloc treq\n");
        return;
@@ -1064,9 +1092,6 @@ afs_FlushActiveVcaches(afs_int32 doflocks)
                 */
                osi_vnhold(tvc, 0);
                ReleaseReadLock(&afs_xvcache);
-#ifdef AFS_BOZONLOCK_ENV
-               afs_BozonLock(&tvc->pvnLock, tvc);
-#endif
 #if defined(AFS_SGI_ENV)
                /*
                 * That's because if we come in via the CUnlinkedDel bit state path we'll be have 0 refcnt
@@ -1088,9 +1113,6 @@ afs_FlushActiveVcaches(afs_int32 doflocks)
                        code = afs_StoreOnLastReference(tvc, treq);
                    }
                    ReleaseWriteLock(&tvc->lock);
-#ifdef AFS_BOZONLOCK_ENV
-                   afs_BozonUnlock(&tvc->pvnLock, tvc);
-#endif
                    hzero(tvc->flushDV);
                    osi_FlushText(tvc);
                    didCore = 1;
@@ -1103,9 +1125,6 @@ afs_FlushActiveVcaches(afs_int32 doflocks)
                     * Ignore errors
                     */
                    ReleaseWriteLock(&tvc->lock);
-#ifdef AFS_BOZONLOCK_ENV
-                   afs_BozonUnlock(&tvc->pvnLock, tvc);
-#endif
 #if defined(AFS_SGI_ENV)
                    AFS_RWUNLOCK((vnode_t *) tvc, VRWLOCK_WRITE);
 #endif
@@ -1116,9 +1135,6 @@ afs_FlushActiveVcaches(afs_int32 doflocks)
                } else {
                    /* lost (or won, perhaps) the race condition */
                    ReleaseWriteLock(&tvc->lock);
-#ifdef AFS_BOZONLOCK_ENV
-                   afs_BozonUnlock(&tvc->pvnLock, tvc);
-#endif
                }
 #if defined(AFS_SGI_ENV)
                AFS_RWUNLOCK((vnode_t *) tvc, VRWLOCK_WRITE);
@@ -1278,7 +1294,7 @@ afs_SimpleVStat(struct vcache *avc,
     } else if (vType(avc) == VLNK) {
        avc->f.m.Mode |= S_IFLNK;
        if ((avc->f.m.Mode & 0111) == 0)
-           avc->mvstat = 1;
+           avc->mvstat = AFS_MVSTAT_MTPT;
     }
     if (avc->f.states & CForeign) {
        struct axscache *ac;
@@ -1430,7 +1446,7 @@ afs_WriteVCacheDiscon(struct vcache *avc,
                } else if (vType(avc) == VLNK) {
                        avc->f.m.Mode |= S_IFLNK;
                        if ((avc->f.m.Mode & 0111) == 0)
-                               avc->mvstat = 1;
+                               avc->mvstat = AFS_MVSTAT_MTPT;
                }
 #endif
                flags |= VDisconSetMode;
@@ -1520,7 +1536,7 @@ afs_ProcessFS(struct vcache *avc,
            avc->f.m.Mode |= S_IFLNK;
        }
        if ((avc->f.m.Mode & 0111) == 0) {
-           avc->mvstat = 1;
+           avc->mvstat = AFS_MVSTAT_MTPT;
        }
     }
     avc->f.anyAccess = astat->AnonymousAccess;
@@ -1797,7 +1813,7 @@ afs_GetVCache(struct VenusFid *afid, struct vrequest *areq,
                tvc->f.states |= CForeign;
            if (newvcache && (tvp->rootVnode == afid->Fid.Vnode)
                && (tvp->rootUnique == afid->Fid.Unique)) {
-               tvc->mvstat = 2;
+               tvc->mvstat = AFS_MVSTAT_ROOT;
            }
        }
        if (tvp->states & VRO)
@@ -1805,11 +1821,11 @@ afs_GetVCache(struct VenusFid *afid, struct vrequest *areq,
        if (tvp->states & VBackup)
            tvc->f.states |= CBackup;
        /* now copy ".." entry back out of volume structure, if necessary */
-       if (tvc->mvstat == 2 && tvp->dotdot.Fid.Volume != 0) {
-           if (!tvc->mvid)
-               tvc->mvid = (struct VenusFid *)
+       if (tvc->mvstat == AFS_MVSTAT_ROOT && tvp->dotdot.Fid.Volume != 0) {
+           if (!tvc->mvid.parent)
+               tvc->mvid.parent = (struct VenusFid *)
                    osi_AllocSmallSpace(sizeof(struct VenusFid));
-           *tvc->mvid = tvp->dotdot;
+           *tvc->mvid.parent = tvp->dotdot;
        }
        afs_PutVolume(tvp, READ_LOCK);
     }
@@ -1985,18 +2001,18 @@ afs_LookupVCache(struct VenusFid *afid, struct vrequest *areq,
                tvc->f.states |= CForeign;
            if (newvcache && (tvp->rootVnode == afid->Fid.Vnode)
                && (tvp->rootUnique == afid->Fid.Unique))
-               tvc->mvstat = 2;
+               tvc->mvstat = AFS_MVSTAT_ROOT;
        }
        if (tvp->states & VRO)
            tvc->f.states |= CRO;
        if (tvp->states & VBackup)
            tvc->f.states |= CBackup;
        /* now copy ".." entry back out of volume structure, if necessary */
-       if (tvc->mvstat == 2 && tvp->dotdot.Fid.Volume != 0) {
-           if (!tvc->mvid)
-               tvc->mvid = (struct VenusFid *)
+       if (tvc->mvstat == AFS_MVSTAT_ROOT && tvp->dotdot.Fid.Volume != 0) {
+           if (!tvc->mvid.parent)
+               tvc->mvid.parent = (struct VenusFid *)
                    osi_AllocSmallSpace(sizeof(struct VenusFid));
-           *tvc->mvid = tvp->dotdot;
+           *tvc->mvid.parent = tvp->dotdot;
        }
     }
 
@@ -2215,13 +2231,13 @@ afs_GetRootVCache(struct VenusFid *afid, struct vrequest *areq,
     /* now copy ".." entry back out of volume structure, if necessary */
     if (newvcache && (tvolp->rootVnode == afid->Fid.Vnode)
        && (tvolp->rootUnique == afid->Fid.Unique)) {
-       tvc->mvstat = 2;
+       tvc->mvstat = AFS_MVSTAT_ROOT;
     }
-    if (tvc->mvstat == 2 && tvolp->dotdot.Fid.Volume != 0) {
-       if (!tvc->mvid)
-           tvc->mvid = (struct VenusFid *)
+    if (tvc->mvstat == AFS_MVSTAT_ROOT && tvolp->dotdot.Fid.Volume != 0) {
+       if (!tvc->mvid.parent)
+           tvc->mvid.parent = (struct VenusFid *)
                osi_AllocSmallSpace(sizeof(struct VenusFid));
-       *tvc->mvid = tvolp->dotdot;
+       *tvc->mvid.parent = tvolp->dotdot;
     }
 
     /* stat the file */
@@ -2527,11 +2543,11 @@ afs_StuffVcache(struct VenusFid *afid,
         * Now, copy ".." entry back out of volume structure, if
         * necessary
         */
-       if (tvc->mvstat == 2 && tvp->dotdot.Fid.Volume != 0) {
-           if (!tvc->mvid)
-               tvc->mvid = (struct VenusFid *)
+       if (tvc->mvstat == AFS_MVSTAT_ROOT && tvp->dotdot.Fid.Volume != 0) {
+           if (!tvc->mvid.parent)
+               tvc->mvid.parent = (struct VenusFid *)
                    osi_AllocSmallSpace(sizeof(struct VenusFid));
-           *tvc->mvid = tvp->dotdot;
+           *tvc->mvid.parent = tvp->dotdot;
        }
     }
     /* store the stat on the file */
@@ -3067,9 +3083,9 @@ shutdown_vcache(void)
        for (tq = VLRU.prev; tq != &VLRU; tq = uq) {
            tvc = QTOV(tq);
            uq = QPrev(tq);
-           if (tvc->mvid) {
-               osi_FreeSmallSpace(tvc->mvid);
-               tvc->mvid = (struct VenusFid *)0;
+           if (tvc->mvid.target_root) {
+               osi_FreeSmallSpace(tvc->mvid.target_root);
+               tvc->mvid.target_root = NULL;
            }
 #ifdef AFS_AIX_ENV
            aix_gnode_rele(AFSTOV(tvc));
@@ -3084,9 +3100,9 @@ shutdown_vcache(void)
         */
        for (i = 0; i < VCSIZE; i++) {
            for (tvc = afs_vhashT[i]; tvc; tvc = tvc->hnext) {
-               if (tvc->mvid) {
-                   osi_FreeSmallSpace(tvc->mvid);
-                   tvc->mvid = (struct VenusFid *)0;
+               if (tvc->mvid.target_root) {
+                   osi_FreeSmallSpace(tvc->mvid.target_root);
+                   tvc->mvid.target_root = NULL;
                }
 #ifdef AFS_AIX_ENV
                if (tvc->v.v_gnode)