Author: mjg
Date: Wed Aug 26 12:50:57 2020
New Revision: 364812
URL: https://svnweb.freebsd.org/changeset/base/364812
Log:
cache: only evict negative entries on CREATE when ISLASTCN is set
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Wed Aug 26 12:50:10 2020 (r364811)
+++ head/sys/kern/vfs_cache.c Wed Aug 26 12:50:57 2020 (r364812)
@@ -1398,15 +1398,17 @@ retry:
return (-1);
negative_success:
if (__predict_false(cnp->cn_nameiop == CREATE)) {
- counter_u64_add(numnegzaps, 1);
- error = cache_zap_locked_vnode(ncp, dvp);
- if (__predict_false(error != 0)) {
- zap_and_exit_bucket_fail2++;
- cache_maybe_yield();
- goto retry;
+ if (cnp->cn_flags & ISLASTCN) {
+ counter_u64_add(numnegzaps, 1);
+ error = cache_zap_locked_vnode(ncp, dvp);
+ if (__predict_false(error != 0)) {
+ zap_and_exit_bucket_fail2++;
+ cache_maybe_yield();
+ goto retry;
+ }
+ cache_free(ncp);
+ return (0);
}
- cache_free(ncp);
- return (0);
}
SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, ncp->nc_name);
@@ -1603,15 +1605,17 @@ retry:
negative_success:
/* We found a negative match, and want to create it, so purge */
if (__predict_false(cnp->cn_nameiop == CREATE)) {
- counter_u64_add(numnegzaps, 1);
- error = cache_zap_rlocked_bucket(ncp, cnp, hash, blp);
- if (__predict_false(error != 0)) {
- zap_and_exit_bucket_fail2++;
- cache_maybe_yield();
- goto retry;
+ if (cnp->cn_flags & ISLASTCN) {
+ counter_u64_add(numnegzaps, 1);
+ error = cache_zap_locked_vnode(ncp, dvp);
+ if (__predict_false(error != 0)) {
+ zap_and_exit_bucket_fail2++;
+ cache_maybe_yield();
+ goto retry;
+ }
+ cache_free(ncp);
+ return (0);
}
- cache_free(ncp);
- return (0);
}
SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, ncp->nc_name);
@@ -1658,13 +1662,6 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, st
return (0);
}
- /*
- * TODO: we only fallback becasue if a negative entry is found it will
- * need to be purged.
- */
- if (cnp->cn_nameiop == CREATE)
- goto out_fallback;
-
hash = cache_get_hash(cnp->cn_nameptr, cnp->cn_namelen, dvp);
vfs_smr_enter();
@@ -1723,6 +1720,13 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, st
return (-1);
negative_success:
+ if (__predict_false(cnp->cn_nameiop == CREATE)) {
+ if (cnp->cn_flags & ISLASTCN) {
+ vfs_smr_exit();
+ goto out_fallback;
+ }
+ }
+
SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, ncp->nc_name);
cache_out_ts(ncp, tsp, ticksp);
counter_u64_add(numneghits, 1);
_______________________________________________
svn-src-head@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
