Date: Mon, 18 Jan 2016 22:21:47 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r294299 - in head: share/man/man9 sys/kern sys/sys Message-ID: <201601182221.u0IMLlWK028295@repo.freebsd.org>
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Author: markj Date: Mon Jan 18 22:21:46 2016 New Revision: 294299 URL: https://svnweb.freebsd.org/changeset/base/294299 Log: Add vrefl(), a locked variant of vref(9). This API has no in-tree consumers at the moment but is useful to at least one out-of-tree consumer, and naturally complements existing vnode refcount functions (vholdl(9), vdropl(9)). Obtained from: kib (sys/ portion) Sponsored by: EMC / Isilon Storage Division Differential Revision: https://reviews.freebsd.org/D4947 Differential Revision: https://reviews.freebsd.org/D4953 Modified: head/share/man/man9/vref.9 head/sys/kern/vfs_subr.c head/sys/sys/vnode.h Modified: head/share/man/man9/vref.9 ============================================================================== --- head/share/man/man9/vref.9 Mon Jan 18 22:12:07 2016 (r294298) +++ head/share/man/man9/vref.9 Mon Jan 18 22:21:46 2016 (r294299) @@ -28,17 +28,19 @@ .\" .\" $FreeBSD$ .\" -.Dd July 24, 1996 +.Dd January 18, 2016 .Dt VREF 9 .Os .Sh NAME -.Nm vref +.Nm vref , vrefl .Nd increment the use count for a vnode .Sh SYNOPSIS .In sys/param.h .In sys/vnode.h .Ft void .Fn vref "struct vnode *vp" +.Ft void +.Fn vrefl "struct vnode *vp" .Sh DESCRIPTION Increment the .Va v_usecount @@ -56,7 +58,14 @@ no longer being used and can be safely r Any code in the system which is using a vnode (e.g.\& during the operation of some algorithm or to store in a data structure) should call -.Fn vref . +.Fn vref +or +.Fn vrefl . +.Pp +.Fn vref +locks the vnode interlock while +.Fn vrefl +expects the interlock to already be held. .Sh SEE ALSO .Xr vget 9 , .Xr vnode 9 , Modified: head/sys/kern/vfs_subr.c ============================================================================== --- head/sys/kern/vfs_subr.c Mon Jan 18 22:12:07 2016 (r294298) +++ head/sys/kern/vfs_subr.c Mon Jan 18 22:21:46 2016 (r294299) @@ -104,6 +104,7 @@ static void syncer_shutdown(void *arg, i static int vtryrecycle(struct vnode *vp); static void v_init_counters(struct vnode *); static void v_incr_usecount(struct vnode *); +static void v_incr_usecount_locked(struct vnode *); static void v_incr_devcount(struct vnode *); static void v_decr_devcount(struct vnode *); static void vnlru_free(int); @@ -2371,6 +2372,20 @@ v_init_counters(struct vnode *vp) refcount_init(&vp->v_usecount, 1); } +static void +v_incr_usecount_locked(struct vnode *vp) +{ + + ASSERT_VI_LOCKED(vp, __func__); + if ((vp->v_iflag & VI_OWEINACT) != 0) { + VNASSERT(vp->v_usecount == 0, vp, + ("vnode with usecount and VI_OWEINACT set")); + vp->v_iflag &= ~VI_OWEINACT; + } + refcount_acquire(&vp->v_usecount); + v_incr_devcount(vp); +} + /* * Increment the use and hold counts on the vnode, taking care to reference * the driver's usecount if this is a chardev. The _vhold() will remove @@ -2383,29 +2398,13 @@ v_incr_usecount(struct vnode *vp) ASSERT_VI_UNLOCKED(vp, __func__); CTR2(KTR_VFS, "%s: vp %p", __func__, vp); - if (vp->v_type == VCHR) { - VI_LOCK(vp); - _vhold(vp, true); - if (vp->v_iflag & VI_OWEINACT) { - VNASSERT(vp->v_usecount == 0, vp, - ("vnode with usecount and VI_OWEINACT set")); - vp->v_iflag &= ~VI_OWEINACT; - } - refcount_acquire(&vp->v_usecount); - v_incr_devcount(vp); - VI_UNLOCK(vp); - return; - } - - _vhold(vp, false); - if (vfs_refcount_acquire_if_not_zero(&vp->v_usecount)) { + if (vp->v_type != VCHR && + vfs_refcount_acquire_if_not_zero(&vp->v_usecount)) { VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp, ("vnode with usecount and VI_OWEINACT set")); } else { VI_LOCK(vp); - if (vp->v_iflag & VI_OWEINACT) - vp->v_iflag &= ~VI_OWEINACT; - refcount_acquire(&vp->v_usecount); + v_incr_usecount_locked(vp); VI_UNLOCK(vp); } } @@ -2520,9 +2519,19 @@ vref(struct vnode *vp) { CTR2(KTR_VFS, "%s: vp %p", __func__, vp); + _vhold(vp, false); v_incr_usecount(vp); } +void +vrefl(struct vnode *vp) +{ + + CTR2(KTR_VFS, "%s: vp %p", __func__, vp); + _vhold(vp, true); + v_incr_usecount_locked(vp); +} + /* * Return reference count of a vnode. * Modified: head/sys/sys/vnode.h ============================================================================== --- head/sys/sys/vnode.h Mon Jan 18 22:12:07 2016 (r294298) +++ head/sys/sys/vnode.h Mon Jan 18 22:21:46 2016 (r294299) @@ -823,6 +823,7 @@ void vop_rename_fail(struct vop_rename_a void vput(struct vnode *vp); void vrele(struct vnode *vp); void vref(struct vnode *vp); +void vrefl(struct vnode *vp); int vrefcnt(struct vnode *vp); void v_addpollinfo(struct vnode *vp);
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