svn commit: r363199 - head/sys/kern
Mateusz Guzik
mjg at FreeBSD.org
Tue Jul 14 21:16:49 UTC 2020
Author: mjg
Date: Tue Jul 14 21:16:48 2020
New Revision: 363199
URL: https://svnweb.freebsd.org/changeset/base/363199
Log:
cache: remove neg_locked argument from cache_zap_locked
Tested by: pho
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Tue Jul 14 21:16:07 2020 (r363198)
+++ head/sys/kern/vfs_cache.c Tue Jul 14 21:16:48 2020 (r363199)
@@ -441,7 +441,7 @@ STATNODE_COUNTER(numneg_evicted,
STATNODE_COUNTER(shrinking_skipped,
"Number of times shrinking was already in progress");
-static void cache_zap_locked(struct namecache *ncp, bool neg_locked);
+static void cache_zap_locked(struct namecache *ncp);
static int vn_fullpath_hardlink(struct thread *td, struct nameidata *ndp, char **retbuf,
char **freebuf, size_t *buflen);
static int vn_fullpath_any(struct thread *td, struct vnode *vp, struct vnode *rdir,
@@ -778,7 +778,7 @@ cache_negative_insert(struct namecache *ncp)
}
static void
-cache_negative_remove(struct namecache *ncp, bool neg_locked)
+cache_negative_remove(struct namecache *ncp)
{
struct neglist *neglist;
struct negstate *negstate;
@@ -788,18 +788,16 @@ cache_negative_remove(struct namecache *ncp, bool neg_
cache_assert_bucket_locked(ncp, RA_WLOCKED);
neglist = NCP2NEGLIST(ncp);
negstate = NCP2NEGSTATE(ncp);
- if (!neg_locked) {
- if ((negstate->neg_flag & NEG_HOT) != 0) {
- hot_locked = true;
- mtx_lock(&ncneg_hot.nl_lock);
- if ((negstate->neg_flag & NEG_HOT) == 0) {
- list_locked = true;
- mtx_lock(&neglist->nl_lock);
- }
- } else {
+ if ((negstate->neg_flag & NEG_HOT) != 0) {
+ hot_locked = true;
+ mtx_lock(&ncneg_hot.nl_lock);
+ if ((negstate->neg_flag & NEG_HOT) == 0) {
list_locked = true;
mtx_lock(&neglist->nl_lock);
}
+ } else {
+ list_locked = true;
+ mtx_lock(&neglist->nl_lock);
}
if ((negstate->neg_flag & NEG_HOT) != 0) {
mtx_assert(&ncneg_hot.nl_lock, MA_OWNED);
@@ -888,19 +886,24 @@ cache_negative_zap_one(void)
mtx_unlock(&neglist->nl_lock);
mtx_lock(dvlp);
rw_wlock(blp);
- mtx_lock(&neglist->nl_lock);
+ /*
+ * Enter SMR to safely check the negative list.
+ * Even if the found pointer matches, the entry may now be reallocated
+ * and used by a different vnode.
+ */
+ vfs_smr_enter();
ncp2 = TAILQ_FIRST(&neglist->nl_list);
if (ncp != ncp2 || dvlp != VP2VNODELOCK(ncp2->nc_dvp) ||
- blp != NCP2BUCKETLOCK(ncp2) || !(ncp2->nc_flag & NCF_NEGATIVE)) {
+ blp != NCP2BUCKETLOCK(ncp2)) {
+ vfs_smr_exit();
ncp = NULL;
} else {
+ vfs_smr_exit();
SDT_PROBE2(vfs, namecache, shrink_negative, done, ncp->nc_dvp,
ncp->nc_name);
-
- cache_zap_locked(ncp, true);
+ cache_zap_locked(ncp);
counter_u64_add(numneg_evicted, 1);
}
- mtx_unlock(&neglist->nl_lock);
rw_wunlock(blp);
mtx_unlock(dvlp);
cache_free(ncp);
@@ -913,7 +916,7 @@ cache_negative_zap_one(void)
* pointer to a vnode or if it is just a negative cache entry.
*/
static void
-cache_zap_locked(struct namecache *ncp, bool neg_locked)
+cache_zap_locked(struct namecache *ncp)
{
if (!(ncp->nc_flag & NCF_NEGATIVE))
@@ -936,7 +939,7 @@ cache_zap_locked(struct namecache *ncp, bool neg_locke
} else {
SDT_PROBE2(vfs, namecache, zap_negative, done, ncp->nc_dvp,
ncp->nc_name);
- cache_negative_remove(ncp, neg_locked);
+ cache_negative_remove(ncp);
}
if (ncp->nc_flag & NCF_ISDOTDOT) {
if (ncp == ncp->nc_dvp->v_cache_dd)
@@ -962,7 +965,7 @@ cache_zap_negative_locked_vnode_kl(struct namecache *n
blp = NCP2BUCKETLOCK(ncp);
rw_wlock(blp);
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
rw_wunlock(blp);
}
@@ -1009,7 +1012,7 @@ cache_zap_locked_vnode_kl2(struct namecache *ncp, stru
}
}
rw_wlock(blp);
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
rw_wunlock(blp);
if (to_unlock != NULL)
mtx_unlock(to_unlock);
@@ -1055,7 +1058,7 @@ cache_zap_locked_vnode(struct namecache *ncp, struct v
to_unlock = vlp1;
}
rw_wlock(blp);
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
rw_wunlock(blp);
mtx_unlock(to_unlock);
out:
@@ -1086,7 +1089,7 @@ cache_zap_unlocked_bucket(struct namecache *ncp, struc
break;
}
if (rncp != NULL) {
- cache_zap_locked(rncp, false);
+ cache_zap_locked(rncp);
rw_wunlock(blp);
cache_unlock_vnodes(dvlp, vlp);
counter_u64_add(zap_and_exit_bucket_relock_success, 1);
@@ -1112,7 +1115,7 @@ cache_zap_wlocked_bucket(struct namecache *ncp, struct
if (!(ncp->nc_flag & NCF_NEGATIVE))
vlp = VP2VNODELOCK(ncp->nc_vp);
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
rw_wunlock(blp);
cache_unlock_vnodes(dvlp, vlp);
return (0);
@@ -1139,7 +1142,7 @@ cache_zap_rlocked_bucket(struct namecache *ncp, struct
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
rw_runlock(blp);
rw_wlock(blp);
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
rw_wunlock(blp);
cache_unlock_vnodes(dvlp, vlp);
return (0);
@@ -1165,7 +1168,7 @@ cache_zap_wlocked_bucket_kl(struct namecache *ncp, str
cache_sort_vnodes(&dvlp, &vlp);
if (*vlpp1 == dvlp && *vlpp2 == vlp) {
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
cache_unlock_vnodes(dvlp, vlp);
*vlpp1 = NULL;
*vlpp2 = NULL;
@@ -1180,7 +1183,7 @@ cache_zap_wlocked_bucket_kl(struct namecache *ncp, str
*vlpp2 = NULL;
if (cache_trylock_vnodes(dvlp, vlp) == 0) {
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
cache_unlock_vnodes(dvlp, vlp);
return (0);
}
@@ -1798,7 +1801,7 @@ cache_enter_dotdot_prep(struct vnode *dvp, struct vnod
ncp = dvp->v_cache_dd;
if (ncp != NULL && (ncp->nc_flag & NCF_ISDOTDOT)) {
KASSERT(ncp->nc_dvp == dvp, ("wrong isdotdot parent"));
- cache_zap_locked(ncp, false);
+ cache_zap_locked(ncp);
} else {
ncp = NULL;
}
@@ -1929,7 +1932,7 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp,
*/
if ((ndd = vp->v_cache_dd) != NULL) {
if ((ndd->nc_flag & NCF_ISDOTDOT) != 0)
- cache_zap_locked(ndd, false);
+ cache_zap_locked(ndd);
else
ndd = NULL;
}
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