Date: Mon, 10 Aug 2020 10:35:18 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r364066 - head/sys/kern Message-ID: <202008101035.07AAZIxL096424@repo.freebsd.org>
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Author: mjg Date: Mon Aug 10 10:35:18 2020 New Revision: 364066 URL: https://svnweb.freebsd.org/changeset/base/364066 Log: vfs: partially support file create/delete/rename in lockless lookup Perform the lookup until the last 2 elements and fallback to slowpath. Tested by: pho Sponsored by: The FreeBSD Foundation Modified: head/sys/kern/vfs_cache.c Modified: head/sys/kern/vfs_cache.c ============================================================================== --- head/sys/kern/vfs_cache.c Mon Aug 10 10:34:22 2020 (r364065) +++ head/sys/kern/vfs_cache.c Mon Aug 10 10:35:18 2020 (r364066) @@ -3143,8 +3143,8 @@ cache_fpl_handled_impl(struct cache_fpl *fpl, int erro #define cache_fpl_handled(x, e) cache_fpl_handled_impl((x), (e), __LINE__) #define CACHE_FPL_SUPPORTED_CN_FLAGS \ - (LOCKLEAF | LOCKPARENT | WANTPARENT | FOLLOW | LOCKSHARED | SAVENAME | \ - ISOPEN | NOMACCHECK | AUDITVNODE1 | AUDITVNODE2) + (LOCKLEAF | LOCKPARENT | WANTPARENT | NOCACHE | FOLLOW | LOCKSHARED | SAVENAME | \ + WILLBEDIR | ISOPEN | NOMACCHECK | AUDITVNODE1 | AUDITVNODE2) #define CACHE_FPL_INTERNAL_CN_FLAGS \ (ISDOTDOT | MAKEENTRY | ISLASTCN) @@ -3194,10 +3194,6 @@ cache_can_fplookup(struct cache_fpl *fpl) cache_fpl_aborted(fpl); return (false); } - if (cnp->cn_nameiop != LOOKUP) { - cache_fpl_aborted(fpl); - return (false); - } if (ndp->ni_dirfd != AT_FDCWD) { cache_fpl_aborted(fpl); return (false); @@ -3407,6 +3403,22 @@ cache_fplookup_final_child(struct cache_fpl *fpl, enum return (cache_fpl_handled(fpl, 0)); } +/* + * They want to possibly modify the state of the namecache. + * + * Don't try to match the API contract, just leave. + * TODO: this leaves scalability on the table + */ +static int +cache_fplookup_final_modifying(struct cache_fpl *fpl) +{ + struct componentname *cnp; + + cnp = fpl->cnp; + MPASS(cnp->cn_nameiop != LOOKUP); + return (cache_fpl_partial(fpl)); +} + static int __noinline cache_fplookup_final_withparent(struct cache_fpl *fpl) { @@ -3489,6 +3501,10 @@ cache_fplookup_final(struct cache_fpl *fpl) VNPASS(cache_fplookup_vnode_supported(dvp), dvp); + if (cnp->cn_nameiop != LOOKUP) { + return (cache_fplookup_final_modifying(fpl)); + } + if ((cnp->cn_flags & (LOCKPARENT|WANTPARENT)) != 0) return (cache_fplookup_final_withparent(fpl)); @@ -3633,6 +3649,12 @@ cache_fplookup_next(struct cache_fpl *fpl) tvp = atomic_load_ptr(&ncp->nc_vp); nc_flag = atomic_load_char(&ncp->nc_flag); if ((nc_flag & NCF_NEGATIVE) != 0) { + /* + * If they want to create an entry we need to replace this one. + */ + if (__predict_false(fpl->cnp->cn_nameiop == CREATE)) { + return (cache_fpl_partial(fpl)); + } negstate = NCP2NEGSTATE(ncp); neg_hot = ((negstate->neg_flag & NEG_HOT) != 0); if (__predict_false(!cache_ncp_canuse(ncp))) {
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