Date: Thu, 19 Apr 2018 06:03:50 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r332755 - in stable/11/sys: cddl/contrib/opensolaris/uts/common/fs kern sys Message-ID: <201804190603.w3J63ogP076646@repo.freebsd.org>
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Author: avg Date: Thu Apr 19 06:03:50 2018 New Revision: 332755 URL: https://svnweb.freebsd.org/changeset/base/332755 Log: MFC r331666: ZFS vn_rele_async: catch up with the use of refcount(9) for the vnode use count It's not sufficient nor required to use the vnode interlock when checking if we are going to drop the last use count as the code in vputx() uses refcount (atomic) operations for both checking and decrementing the use code. Apply the same method to vn_rele_async(). While here, remove vn_rele_inactive(), a wrapper around vrele() that didn't add any value. Also, the change required making vfs_refcount_release_if_not_last() public. I've made vfs_refcount_acquire_if_not_zero() public as well. They are in sys/refcount.h now. While making the move I've dropped the vfs_ prefix. Sponsored by: Panzura Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c stable/11/sys/kern/vfs_subr.c stable/11/sys/sys/refcount.h Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c ============================================================================== --- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c Thu Apr 19 05:52:47 2018 (r332754) +++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/vnode.c Thu Apr 19 06:03:50 2018 (r332755) @@ -72,12 +72,6 @@ xva_getxoptattr(xvattr_t *xvap) return (xoap); } -static void -vn_rele_inactive(vnode_t *vp) -{ - vrele(vp); -} - /* * Like vn_rele() except if we are going to call VOP_INACTIVE() then do it * asynchronously using a taskq. This can avoid deadlocks caused by re-entering @@ -92,13 +86,10 @@ void vn_rele_async(vnode_t *vp, taskq_t *taskq) { VERIFY(vp->v_count > 0); - VI_LOCK(vp); - if (vp->v_count == 1 && !(vp->v_iflag & VI_DOINGINACT)) { - VI_UNLOCK(vp); - VERIFY(taskq_dispatch((taskq_t *)taskq, - (task_func_t *)vn_rele_inactive, vp, TQ_SLEEP) != 0); + if (refcount_release_if_not_last(&vp->v_usecount)) { + vdrop(vp); return; } - refcount_release(&vp->v_usecount); - vdropl(vp); + VERIFY(taskq_dispatch((taskq_t *)taskq, + (task_func_t *)vrele, vp, TQ_SLEEP) != 0); } Modified: stable/11/sys/kern/vfs_subr.c ============================================================================== --- stable/11/sys/kern/vfs_subr.c Thu Apr 19 05:52:47 2018 (r332754) +++ stable/11/sys/kern/vfs_subr.c Thu Apr 19 06:03:50 2018 (r332755) @@ -2389,37 +2389,6 @@ reassignbuf(struct buf *bp) BO_UNLOCK(bo); } -/* - * A temporary hack until refcount_* APIs are sorted out. - */ -static __inline int -vfs_refcount_acquire_if_not_zero(volatile u_int *count) -{ - u_int old; - - old = *count; - for (;;) { - if (old == 0) - return (0); - if (atomic_fcmpset_int(count, &old, old + 1)) - return (1); - } -} - -static __inline int -vfs_refcount_release_if_not_last(volatile u_int *count) -{ - u_int old; - - old = *count; - for (;;) { - if (old == 1) - return (0); - if (atomic_fcmpset_int(count, &old, old - 1)) - return (1); - } -} - static void v_init_counters(struct vnode *vp) { @@ -2459,7 +2428,7 @@ v_incr_usecount(struct vnode *vp) CTR2(KTR_VFS, "%s: vp %p", __func__, vp); if (vp->v_type != VCHR && - vfs_refcount_acquire_if_not_zero(&vp->v_usecount)) { + refcount_acquire_if_not_zero(&vp->v_usecount)) { VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp, ("vnode with usecount and VI_OWEINACT set")); } else { @@ -2551,7 +2520,7 @@ vget(struct vnode *vp, int flags, struct thread *td) * Upgrade our holdcnt to a usecount. */ if (vp->v_type == VCHR || - !vfs_refcount_acquire_if_not_zero(&vp->v_usecount)) { + !refcount_acquire_if_not_zero(&vp->v_usecount)) { VI_LOCK(vp); if ((vp->v_iflag & VI_OWEINACT) == 0) { oweinact = 0; @@ -2654,7 +2623,7 @@ vputx(struct vnode *vp, int func) CTR2(KTR_VFS, "%s: vp %p", __func__, vp); if (vp->v_type != VCHR && - vfs_refcount_release_if_not_last(&vp->v_usecount)) { + refcount_release_if_not_last(&vp->v_usecount)) { if (func == VPUTX_VPUT) VOP_UNLOCK(vp, 0); vdrop(vp); @@ -2770,7 +2739,7 @@ _vhold(struct vnode *vp, bool locked) ASSERT_VI_UNLOCKED(vp, __func__); CTR2(KTR_VFS, "%s: vp %p", __func__, vp); if (!locked) { - if (vfs_refcount_acquire_if_not_zero(&vp->v_holdcnt)) { + if (refcount_acquire_if_not_zero(&vp->v_holdcnt)) { VNASSERT((vp->v_iflag & VI_FREE) == 0, vp, ("_vhold: vnode with holdcnt is free")); return; @@ -2831,7 +2800,7 @@ _vdrop(struct vnode *vp, bool locked) if ((int)vp->v_holdcnt <= 0) panic("vdrop: holdcnt %d", vp->v_holdcnt); if (!locked) { - if (vfs_refcount_release_if_not_last(&vp->v_holdcnt)) + if (refcount_release_if_not_last(&vp->v_holdcnt)) return; VI_LOCK(vp); } Modified: stable/11/sys/sys/refcount.h ============================================================================== --- stable/11/sys/sys/refcount.h Thu Apr 19 05:52:47 2018 (r332754) +++ stable/11/sys/sys/refcount.h Thu Apr 19 06:03:50 2018 (r332755) @@ -74,4 +74,35 @@ refcount_release(volatile u_int *count) return (1); } +/* + * A temporary hack until refcount_* APIs are sorted out. + */ +static __inline int +refcount_acquire_if_not_zero(volatile u_int *count) +{ + u_int old; + + old = *count; + for (;;) { + if (old == 0) + return (0); + if (atomic_fcmpset_int(count, &old, old + 1)) + return (1); + } +} + +static __inline int +refcount_release_if_not_last(volatile u_int *count) +{ + u_int old; + + old = *count; + for (;;) { + if (old == 1) + return (0); + if (atomic_fcmpset_int(count, &old, old - 1)) + return (1); + } +} + #endif /* ! __SYS_REFCOUNT_H__ */
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