diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index ac468567ef2..c22a005682e 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -432,6 +432,50 @@ SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD| "nchash statistics (number of total/used buckets, maximum chain length, usage percentage)"); #endif +/* + * Negative entries management + */ +static void +cache_negative_hit(struct namecache *ncp) +{ + + rw_assert(&cache_lock, RA_WLOCKED); + TAILQ_REMOVE(&ncneg, ncp, nc_dst); + TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); +} + +static void +cache_negative_insert(struct namecache *ncp) +{ + + rw_assert(&cache_lock, RA_WLOCKED); + MPASS(ncp->nc_vp == NULL); + TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); + numneg++; +} + +static void +cache_negative_remove(struct namecache *ncp) +{ + + rw_assert(&cache_lock, RA_WLOCKED); + MPASS(ncp->nc_vp == NULL); + TAILQ_REMOVE(&ncneg, ncp, nc_dst); + numneg--; +} + +static void +cache_negative_zap_one(void) +{ + struct namecache *ncp; + + rw_assert(&cache_lock, RA_WLOCKED); + ncp = TAILQ_FIRST(&ncneg); + KASSERT(ncp->nc_vp == NULL, ("ncp %p vp %p on ncneg", + ncp, ncp->nc_vp)); + cache_zap(ncp); +} + /* * cache_zap(): * @@ -469,8 +513,7 @@ cache_zap(struct namecache *ncp) if (ncp == ncp->nc_vp->v_cache_dd) ncp->nc_vp->v_cache_dd = NULL; } else { - TAILQ_REMOVE(&ncneg, ncp, nc_dst); - numneg--; + cache_negative_remove(ncp); } numcache--; cache_free(ncp); @@ -640,14 +683,7 @@ negative_success: if (!wlocked && !CACHE_UPGRADE_LOCK()) goto wlock; counter_u64_add(numneghits, 1); - /* - * We found a "negative" match, so we shift it to the end of - * the "negative" cache entries queue to satisfy LRU. Also, - * check to see if the entry is a whiteout; indicate this to - * the componentname, if so. - */ - TAILQ_REMOVE(&ncneg, ncp, nc_dst); - TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); + cache_negative_hit(ncp); if (ncp->nc_flag & NCF_WHITE) cnp->cn_flags |= ISWHITEOUT; SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp, @@ -759,15 +795,13 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst); } else { - TAILQ_REMOVE(&ncneg, ncp, nc_dst); - numneg--; + cache_negative_remove(ncp); } if (vp != NULL) { TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst); } else { - TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); - numneg++; + cache_negative_insert(ncp); } ncp->nc_vp = vp; CACHE_WUNLOCK(); @@ -893,17 +927,12 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp, struct componentname *cnp, } else { if (cnp->cn_flags & ISWHITEOUT) ncp->nc_flag |= NCF_WHITE; - TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst); - numneg++; + cache_negative_insert(ncp); SDT_PROBE2(vfs, namecache, enter_negative, done, dvp, nc_get_name(ncp)); } - if (numneg * ncnegfactor > numcache) { - ncp = TAILQ_FIRST(&ncneg); - KASSERT(ncp->nc_vp == NULL, ("ncp %p vp %p on ncneg", - ncp, ncp->nc_vp)); - cache_zap(ncp); - } + if (numneg * ncnegfactor > numcache) + cache_negative_zap_one(); CACHE_WUNLOCK(); }