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Eliminate v_id and v_ddid. The name cache now holds references to

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vnodes whose names it caches, so we no longer need a `generation
number' to tell us if a referenced vnode is invalid.  Replace the use
of the parent's v_id in the hash function with the address of the
parent vnode.

Tested by:	Peter Holm
Glanced at by:	jeff, phk
This commit is contained in:
David Schultz 2005-03-30 03:01:36 +00:00
parent dd33f0d92f
commit 7ce7f713ee
2 changed files with 11 additions and 38 deletions
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46
sys/kern/vfs_cache.c
View File

@ -361,9 +361,8 @@ cache_lookup(dvp, vpp, cnp)
}
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
dotdothits++;
if (dvp->v_dd->v_id != dvp->v_ddid ||
if (dvp->v_dd == NULL ||
(cnp->cn_flags & MAKEENTRY) == 0) {
dvp->v_ddid = 0;
CACHE_UNLOCK();
return (0);
}
@ -373,7 +372,7 @@ cache_lookup(dvp, vpp, cnp)
}
hash = fnv_32_buf(cnp->cn_nameptr, cnp->cn_namelen, FNV1_32_INIT);
hash = fnv_32_buf(&dvp->v_id, sizeof(dvp->v_id), hash);
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
numchecks++;
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
@ -481,13 +480,7 @@ cache_enter(dvp, vp, cnp)
return;
}
if (cnp->cn_namelen == 2 && cnp->cn_nameptr[1] == '.') {
if (vp) {
dvp->v_dd = vp;
dvp->v_ddid = vp->v_id;
} else {
dvp->v_dd = dvp;
dvp->v_ddid = 0;
}
dvp->v_dd = vp;
return;
}
}
@ -502,7 +495,8 @@ cache_enter(dvp, vp, cnp)
ncp->nc_flag = cnp->cn_flags & ISWHITEOUT ? NCF_WHITE : 0;
} else if (vp->v_type == VDIR) {
vp->v_dd = dvp;
vp->v_ddid = dvp->v_id;
} else {
vp->v_dd = NULL;
}
/*
@ -515,7 +509,7 @@ cache_enter(dvp, vp, cnp)
len = ncp->nc_nlen = cnp->cn_namelen;
hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT);
bcopy(cnp->cn_nameptr, ncp->nc_name, len);
hash = fnv_32_buf(&dvp->v_id, sizeof(dvp->v_id), hash);
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
ncpp = NCHHASH(hash);
LIST_INSERT_HEAD(ncpp, ncp, nc_hash);
if (LIST_EMPTY(&dvp->v_cache_src)) {
@ -565,25 +559,12 @@ SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_SECOND, nchinit, NULL)
/*
* Invalidate all entries to a particular vnode.
*
* Remove all entries in the namecache relating to this vnode and
* change the v_id. We take the v_id from a global counter, since
* it becomes a handy sequence number in crash-dumps that way.
* No valid vnode will ever have (v_id == 0).
*
* XXX: Only time and the size of v_id prevents this from failing:
* XXX: In theory we should hunt down all (struct vnode*, v_id)
* XXX: soft references and nuke them, at least on the global
* XXX: v_id wraparound. The period of resistance can be extended
* XXX: by incrementing each vnodes v_id individually instead of
* XXX: using the global v_id.
*/
void
cache_purge(vp)
struct vnode *vp;
{
struct namecache *ncp;
static u_long nextid;
CACHE_LOCK();
while (!LIST_EMPTY(&vp->v_cache_src)) {
@ -594,20 +575,13 @@ cache_purge(vp)
* We must reset v_dd of any children so they don't
* continue to point to us.
*/
if ((cvp = ncp->nc_vp) && cvp->v_dd == vp) {
cvp->v_dd = cvp;
cvp->v_ddid = 0;
}
if ((cvp = ncp->nc_vp) && cvp->v_dd == vp)
cvp->v_dd = NULL;
cache_zap(ncp);
}
while (!TAILQ_EMPTY(&vp->v_cache_dst))
cache_zap(TAILQ_FIRST(&vp->v_cache_dst));
do
nextid++;
while (nextid == vp->v_id || !nextid);
vp->v_id = nextid;
vp->v_dd = vp;
vp->v_ddid = 0;
vp->v_dd = NULL;
CACHE_UNLOCK();
}
@ -843,7 +817,7 @@ vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
vp = vp->v_mount->mnt_vnodecovered;
continue;
}
if (vp->v_dd->v_id != vp->v_ddid) {
if (vp->v_dd == NULL) {
numfullpathfail1++;
error = ENOTDIR;
break;

3
sys/kern/vfs_subr.c
View File

@ -847,7 +847,6 @@ getnewvnode(tag, mp, vops, vpp)
*/
LIST_INIT(&vp->v_cache_src);
TAILQ_INIT(&vp->v_cache_dst);
cache_purge(vp); /* Sets up v_id. */
/*
* Finalize various vnode identity bits.
*/
@ -2564,11 +2563,11 @@ sysctl_vnode(SYSCTL_HANDLER_ARGS)
vref(vp);
xvn[n].xv_size = sizeof *xvn;
xvn[n].xv_vnode = vp;
xvn[n].xv_id = 0; /* XXX compat */
#define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
XV_COPY(usecount);
XV_COPY(writecount);
XV_COPY(holdcnt);
XV_COPY(id);
XV_COPY(mount);
XV_COPY(numoutput);
XV_COPY(type);