Date: Sat, 21 Jan 2017 21:51:14 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Mateusz Guzik <mjg@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r312600 - head/sys/kern Message-ID: <20170121195114.GA2349@kib.kiev.ua> In-Reply-To: <201701211838.v0LIcHIv072626@repo.freebsd.org> References: <201701211838.v0LIcHIv072626@repo.freebsd.org>
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On Sat, Jan 21, 2017 at 06:38:17PM +0000, Mateusz Guzik wrote: > Author: mjg > Date: Sat Jan 21 18:38:16 2017 > New Revision: 312600 > URL: https://svnweb.freebsd.org/changeset/base/312600 > > Log: > vfs: refactor _vn_lock > > Stop testing for LK_RETRY and error multiple times. Also postpone the > VI_DOOMED until after LK_RETRY was seen as it reads from the vnode. > > No functional changes. > > Modified: > head/sys/kern/vfs_vnops.c > > Modified: head/sys/kern/vfs_vnops.c > ============================================================================== > --- head/sys/kern/vfs_vnops.c Sat Jan 21 17:39:10 2017 (r312599) > +++ head/sys/kern/vfs_vnops.c Sat Jan 21 18:38:16 2017 (r312600) > @@ -1539,27 +1539,24 @@ _vn_lock(struct vnode *vp, int flags, ch > > VNASSERT((flags & LK_TYPE_MASK) != 0, vp, > ("vn_lock called with no locktype.")); > - do { > #ifdef DEBUG_VFS_LOCKS > - KASSERT(vp->v_holdcnt != 0, > - ("vn_lock %p: zero hold count", vp)); > + KASSERT(vp->v_holdcnt != 0, > + ("vn_lock %p: zero hold count", vp)); This line also has wrong inde seems to not be fixed by later commit. > #endif > - error = VOP_LOCK1(vp, flags, file, line); > - flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ > - KASSERT((flags & LK_RETRY) == 0 || error == 0, > - ("LK_RETRY set with incompatible flags (0x%x) or an error occurred (%d)", > - flags, error)); > - /* > - * Callers specify LK_RETRY if they wish to get dead vnodes. > - * If RETRY is not set, we return ENOENT instead. > - */ > - if (error == 0 && vp->v_iflag & VI_DOOMED && > - (flags & LK_RETRY) == 0) { > +retry: > + error = VOP_LOCK1(vp, flags, file, line); > + flags &= ~LK_INTERLOCK; /* Interlock is always dropped. */ > + KASSERT((flags & LK_RETRY) == 0 || error == 0, > + ("LK_RETRY set with incompatible flags (0x%x) or an error occurred (%d)", > + flags, error)); > + if (flags & LK_RETRY) { Stylish test is if ((flags & LK_RETRY) != 0) { > + if ((error != 0)) Too many (). > + goto retry; > + if ((vp->v_iflag & VI_DOOMED)) { Too many braces again, or missed != 0. > VOP_UNLOCK(vp, 0); > error = ENOENT; > - break; Also, this does the functional change, it seems to completely break LK_RERY logic. If LK_RETRY is specified, VI_DOOMED must not result in ENOENT. > } > - } while (flags & LK_RETRY && error != 0); > + } > return (error); > } >
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