svn commit: r364857 - head/sys/kern
Mateusz Guzik
mjg at FreeBSD.org
Thu Aug 27 06:31:28 UTC 2020
Author: mjg
Date: Thu Aug 27 06:31:27 2020
New Revision: 364857
URL: https://svnweb.freebsd.org/changeset/base/364857
Log:
cache: assorted clean ups
In particular remove spurious comments, duplicate assertions and the
inconsistently done KTR support.
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Thu Aug 27 06:30:40 2020 (r364856)
+++ head/sys/kern/vfs_cache.c Thu Aug 27 06:31:27 2020 (r364857)
@@ -999,9 +999,6 @@ cache_zap_locked(struct namecache *ncp)
cache_assert_vnode_locked(ncp->nc_dvp);
cache_assert_bucket_locked(ncp);
- CTR2(KTR_VFS, "cache_zap(%p) vp %p", ncp,
- (ncp->nc_flag & NCF_NEGATIVE) ? NULL : ncp->nc_vp);
-
cache_ncp_invalidate(ncp);
ncpp = NCP2BUCKET(ncp);
@@ -1260,6 +1257,83 @@ cache_zap_locked_bucket_kl(struct namecache *ncp, stru
return (EAGAIN);
}
+static __noinline int
+cache_remove_cnp(struct vnode *dvp, struct componentname *cnp)
+{
+ struct namecache *ncp;
+ struct mtx *blp;
+ struct mtx *dvlp, *dvlp2;
+ uint32_t hash;
+ int error;
+
+ if (cnp->cn_namelen == 2 &&
+ cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
+ dvlp = VP2VNODELOCK(dvp);
+ dvlp2 = NULL;
+ mtx_lock(dvlp);
+retry_dotdot:
+ ncp = dvp->v_cache_dd;
+ if (ncp == NULL) {
+ mtx_unlock(dvlp);
+ if (dvlp2 != NULL)
+ mtx_unlock(dvlp2);
+ SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
+ return (0);
+ }
+ if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
+ if (!cache_zap_locked_vnode_kl2(ncp, dvp, &dvlp2))
+ goto retry_dotdot;
+ MPASS(dvp->v_cache_dd == NULL);
+ mtx_unlock(dvlp);
+ if (dvlp2 != NULL)
+ mtx_unlock(dvlp2);
+ cache_free(ncp);
+ } else {
+ vn_seqc_write_begin(dvp);
+ dvp->v_cache_dd = NULL;
+ vn_seqc_write_end(dvp);
+ mtx_unlock(dvlp);
+ if (dvlp2 != NULL)
+ mtx_unlock(dvlp2);
+ }
+ SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
+ return (1);
+ }
+
+ hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
+ blp = HASH2BUCKETLOCK(hash);
+retry:
+ if (CK_SLIST_EMPTY(NCHHASH(hash)))
+ goto out_no_entry;
+
+ mtx_lock(blp);
+
+ CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
+ if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
+ !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
+ break;
+ }
+
+ if (ncp == NULL) {
+ mtx_unlock(blp);
+ goto out_no_entry;
+ }
+
+ error = cache_zap_locked_bucket(ncp, cnp, hash, blp);
+ if (__predict_false(error != 0)) {
+ zap_and_exit_bucket_fail++;
+ goto retry;
+ }
+ counter_u64_add(numposzaps, 1);
+ SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
+ cache_free(ncp);
+ return (1);
+out_no_entry:
+ counter_u64_add(nummisszap, 1);
+ SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
+ return (0);
+}
+
static int __noinline
cache_lookup_dot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
struct timespec *tsp, int *ticksp)
@@ -1267,8 +1341,6 @@ cache_lookup_dot(struct vnode *dvp, struct vnode **vpp
int ltype;
*vpp = dvp;
- CTR2(KTR_VFS, "cache_lookup(%p, %s) found via .",
- dvp, cnp->cn_nameptr);
counter_u64_add(dothits, 1);
SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ".", *vpp);
if (tsp != NULL)
@@ -1296,10 +1368,6 @@ cache_lookup_dot(struct vnode *dvp, struct vnode **vpp
return (-1);
}
-static __noinline int
-cache_remove_cnp(struct vnode *dvp, struct componentname *cnp);
-
-
static int __noinline
cache_lookup_dotdot(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
struct timespec *tsp, int *ticksp)
@@ -1324,8 +1392,7 @@ retry:
mtx_lock(dvlp);
ncp = dvp->v_cache_dd;
if (ncp == NULL) {
- SDT_PROBE3(vfs, namecache, lookup, miss, dvp,
- "..", NULL);
+ SDT_PROBE3(vfs, namecache, lookup, miss, dvp, "..", NULL);
mtx_unlock(dvlp);
return (0);
}
@@ -1336,13 +1403,9 @@ retry:
*vpp = ncp->nc_vp;
} else
*vpp = ncp->nc_dvp;
- /* Return failure if negative entry was found. */
if (*vpp == NULL)
goto negative_success;
- CTR3(KTR_VFS, "cache_lookup(%p, %s) found %p via ..",
- dvp, cnp->cn_nameptr, *vpp);
- SDT_PROBE3(vfs, namecache, lookup, hit, dvp, "..",
- *vpp);
+ SDT_PROBE3(vfs, namecache, lookup, hit, dvp, "..", *vpp);
cache_out_ts(ncp, tsp, ticksp);
if ((ncp->nc_flag & (NCF_ISDOTDOT | NCF_DTS)) ==
NCF_DTS && tsp != NULL) {
@@ -1350,12 +1413,7 @@ retry:
*tsp = ncp_ts->nc_dotdottime;
}
- /*
- * On success we return a locked and ref'd vnode as per the lookup
- * protocol.
- */
MPASS(dvp != *vpp);
- ltype = 0; /* silence gcc warning */
ltype = VOP_ISLOCKED(dvp);
VOP_UNLOCK(dvp);
vs = vget_prep(*vpp);
@@ -1372,10 +1430,6 @@ retry:
*vpp = NULL;
goto retry;
}
- if ((cnp->cn_flags & ISLASTCN) &&
- (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
- ASSERT_VOP_ELOCKED(*vpp, "cache_lookup");
- }
return (-1);
negative_success:
if (__predict_false(cnp->cn_nameiop == CREATE)) {
@@ -1402,87 +1456,6 @@ negative_success:
return (ENOENT);
}
-static __noinline int
-cache_remove_cnp(struct vnode *dvp, struct componentname *cnp)
-{
- struct namecache *ncp;
- struct mtx *blp;
- struct mtx *dvlp, *dvlp2;
- uint32_t hash;
- int error;
-
- if (cnp->cn_namelen == 2 &&
- cnp->cn_nameptr[0] == '.' && cnp->cn_nameptr[1] == '.') {
- dvlp = VP2VNODELOCK(dvp);
- dvlp2 = NULL;
- mtx_lock(dvlp);
-retry_dotdot:
- ncp = dvp->v_cache_dd;
- if (ncp == NULL) {
- mtx_unlock(dvlp);
- if (dvlp2 != NULL)
- mtx_unlock(dvlp2);
- SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
- return (0);
- }
- if ((ncp->nc_flag & NCF_ISDOTDOT) != 0) {
- if (ncp->nc_dvp != dvp)
- panic("dvp %p v_cache_dd %p\n", dvp, ncp);
- if (!cache_zap_locked_vnode_kl2(ncp,
- dvp, &dvlp2))
- goto retry_dotdot;
- MPASS(dvp->v_cache_dd == NULL);
- mtx_unlock(dvlp);
- if (dvlp2 != NULL)
- mtx_unlock(dvlp2);
- cache_free(ncp);
- } else {
- vn_seqc_write_begin(dvp);
- dvp->v_cache_dd = NULL;
- vn_seqc_write_end(dvp);
- mtx_unlock(dvlp);
- if (dvlp2 != NULL)
- mtx_unlock(dvlp2);
- }
- SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
- return (1);
- }
-
- hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
- blp = HASH2BUCKETLOCK(hash);
-retry:
- if (CK_SLIST_EMPTY(NCHHASH(hash)))
- goto out_no_entry;
-
- mtx_lock(blp);
-
- CK_SLIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
- if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
- !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
- break;
- }
-
- /* We failed to find an entry */
- if (ncp == NULL) {
- mtx_unlock(blp);
- goto out_no_entry;
- }
-
- error = cache_zap_locked_bucket(ncp, cnp, hash, blp);
- if (__predict_false(error != 0)) {
- zap_and_exit_bucket_fail++;
- goto retry;
- }
- counter_u64_add(numposzaps, 1);
- cache_free(ncp);
- SDT_PROBE2(vfs, namecache, removecnp, hit, dvp, cnp);
- return (1);
-out_no_entry:
- SDT_PROBE2(vfs, namecache, removecnp, miss, dvp, cnp);
- counter_u64_add(nummisszap, 1);
- return (0);
-}
-
/**
* Lookup a name in the name cache
*
@@ -1504,6 +1477,8 @@ out_no_entry:
* that was current when the cache entry was created, unless cnp
* was ".".
*
+ * Either both tsp and ticks have to be provided or neither of them.
+ *
* # Returns
*
* - -1: A positive cache hit. vpp will contain the desired vnode.
@@ -1543,7 +1518,6 @@ retry:
break;
}
- /* We failed to find an entry */
if (__predict_false(ncp == NULL)) {
mtx_unlock(blp);
SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr,
@@ -1555,18 +1529,10 @@ retry:
if (ncp->nc_flag & NCF_NEGATIVE)
goto negative_success;
- /* We found a "positive" match, return the vnode */
counter_u64_add(numposhits, 1);
*vpp = ncp->nc_vp;
- CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
- dvp, cnp->cn_nameptr, *vpp, ncp);
- SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
- *vpp);
+ SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name, *vpp);
cache_out_ts(ncp, tsp, ticksp);
- /*
- * On success we return a locked and ref'd vnode as per the lookup
- * protocol.
- */
MPASS(dvp != *vpp);
vs = vget_prep(*vpp);
mtx_unlock(blp);
@@ -1575,14 +1541,8 @@ retry:
*vpp = NULL;
goto retry;
}
- if ((cnp->cn_flags & ISLASTCN) &&
- (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
- ASSERT_VOP_ELOCKED(*vpp, "cache_lookup");
- }
return (-1);
-
negative_success:
- /* We found a negative match, and want to create it, so purge */
if (__predict_false(cnp->cn_nameiop == CREATE)) {
if (cnp->cn_flags & ISLASTCN) {
counter_u64_add(numnegzaps, 1);
@@ -1651,7 +1611,6 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, st
break;
}
- /* We failed to find an entry */
if (__predict_false(ncp == NULL)) {
vfs_smr_exit();
SDT_PROBE3(vfs, namecache, lookup, miss, dvp, cnp->cn_nameptr,
@@ -1664,18 +1623,10 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, st
if (nc_flag & NCF_NEGATIVE)
goto negative_success;
- /* We found a "positive" match, return the vnode */
counter_u64_add(numposhits, 1);
*vpp = ncp->nc_vp;
- CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
- dvp, cnp->cn_nameptr, *vpp, ncp);
- SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
- *vpp);
+ SDT_PROBE3(vfs, namecache, lookup, hit, dvp, ncp->nc_name, *vpp);
cache_out_ts(ncp, tsp, ticksp);
- /*
- * On success we return a locked and ref'd vnode as per the lookup
- * protocol.
- */
MPASS(dvp != *vpp);
if (!cache_ncp_canuse(ncp)) {
vfs_smr_exit();
@@ -1693,12 +1644,7 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, st
*vpp = NULL;
goto out_fallback;
}
- if ((cnp->cn_flags & ISLASTCN) &&
- (cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE) {
- ASSERT_VOP_ELOCKED(*vpp, "cache_lookup");
- }
return (-1);
-
negative_success:
if (__predict_false(cnp->cn_nameiop == CREATE)) {
if (cnp->cn_flags & ISLASTCN) {
@@ -1712,7 +1658,8 @@ negative_success:
counter_u64_add(numneghits, 1);
whiteout = (ncp->nc_flag & NCF_WHITE);
/*
- * We need to take locks to promote an entry.
+ * TODO: We need to take locks to promote an entry. Code doing it
+ * in SMR lookup can be modified to be shared.
*/
negstate = NCP2NEGSTATE(ncp);
if ((negstate->neg_flag & NEG_HOT) == 0 ||
@@ -1850,8 +1797,7 @@ cache_unlock_buckets_cel(struct celockstate *cel)
*
* This means vnodelocks for dvp, vp and the relevant bucketlock.
* However, insertion can result in removal of an old entry. In this
- * case we have an additional vnode and bucketlock pair to lock. If the
- * entry is negative, ncelock is locked instead of the vnode.
+ * case we have an additional vnode and bucketlock pair to lock.
*
* That is, in the worst case we have to lock 3 vnodes and 2 bucketlocks, while
* preserving the locking order (smaller address first).
@@ -1986,7 +1932,6 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp,
int len;
u_long lnumcache;
- CTR3(KTR_VFS, "cache_enter(%p, %p, %s)", dvp, vp, cnp->cn_nameptr);
VNPASS(!VN_IS_DOOMED(dvp), dvp);
VNPASS(dvp->v_type != VNON, dvp);
if (vp != NULL) {
@@ -2416,7 +2361,6 @@ cache_purge_negative(struct vnode *vp)
struct namecache *ncp, *nnp;
struct mtx *vlp;
- CTR1(KTR_VFS, "cache_purge_negative(%p)", vp);
SDT_PROBE1(vfs, namecache, purge_negative, done, vp);
if (LIST_EMPTY(&vp->v_cache_src))
return;
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