- in genfs_getpages, take g_glock earlier so that it can't be
intervened by truncation. it also fixes a deadlock. (g_glock vs pages locking order) - uvm_vnp_setsize: modify v_size while holding v_interlock. reviewed by Chuck Silvers.
This commit is contained in:
yamt
parent
f94a2b9563
commit
f9458a6ba1
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@ -1,4 +1,4 @@
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/* $NetBSD: genfs_vnops.c,v 1.125 2006/05/14 21:31:52 elad Exp $ */
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/* $NetBSD: genfs_vnops.c,v 1.126 2006/07/22 08:47:56 yamt Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1989, 1993
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@ -31,7 +31,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: genfs_vnops.c,v 1.125 2006/05/14 21:31:52 elad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: genfs_vnops.c,v 1.126 2006/07/22 08:47:56 yamt Exp $");
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#if defined(_KERNEL_OPT)
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#include "opt_nfsserver.h"
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@ -460,6 +460,7 @@ genfs_getpages(void *v)
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boolean_t sawhole = FALSE;
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boolean_t overwrite = (flags & PGO_OVERWRITE) != 0;
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boolean_t blockalloc = write && (flags & PGO_NOBLOCKALLOC) == 0;
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voff_t origvsize;
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UVMHIST_FUNC("genfs_getpages"); UVMHIST_CALLED(ubchist);
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UVMHIST_LOG(ubchist, "vp %p off 0x%x/%x count %d",
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@ -473,7 +474,9 @@ genfs_getpages(void *v)
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panic("genfs_getpages: too many pages");
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}
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startover:
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error = 0;
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origvsize = vp->v_size;
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origoffset = ap->a_offset;
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orignpages = *ap->a_count;
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GOP_SIZE(vp, vp->v_size, &diskeof, 0);
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@ -539,6 +542,7 @@ genfs_getpages(void *v)
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return (ap->a_m[ap->a_centeridx] == NULL ? EBUSY : 0);
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}
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simple_unlock(&uobj->vmobjlock);
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/*
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* find the requested pages and make some simple checks.
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@ -566,9 +570,9 @@ genfs_getpages(void *v)
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pgs_size = sizeof(struct vm_page *) *
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((endoffset - startoffset) >> PAGE_SHIFT);
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if (pgs_size > sizeof(pgs_onstack)) {
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pgs = malloc(pgs_size, M_DEVBUF, M_NOWAIT | M_ZERO);
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pgs = malloc(pgs_size, M_DEVBUF,
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(async ? M_NOWAIT : M_WAITOK) | M_ZERO);
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if (pgs == NULL) {
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simple_unlock(&uobj->vmobjlock);
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return (ENOMEM);
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}
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} else {
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@ -577,8 +581,29 @@ genfs_getpages(void *v)
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}
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UVMHIST_LOG(ubchist, "ridx %d npages %d startoff %ld endoff %ld",
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ridx, npages, startoffset, endoffset);
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/*
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* hold g_glock to prevent a race with truncate.
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*
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* check if our idea of v_size is still valid.
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*/
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if (blockalloc) {
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lockmgr(&gp->g_glock, LK_EXCLUSIVE, NULL);
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} else {
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lockmgr(&gp->g_glock, LK_SHARED, NULL);
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}
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simple_lock(&uobj->vmobjlock);
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if (vp->v_size < origvsize) {
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lockmgr(&gp->g_glock, LK_RELEASE, NULL);
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if (pgs != pgs_onstack)
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free(pgs, M_DEVBUF);
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goto startover;
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}
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if (uvn_findpages(uobj, origoffset, &npages, &pgs[ridx],
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async ? UFP_NOWAIT : UFP_ALL) != orignpages) {
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lockmgr(&gp->g_glock, LK_RELEASE, NULL);
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KASSERT(async != 0);
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genfs_rel_pages(&pgs[ridx], orignpages);
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simple_unlock(&uobj->vmobjlock);
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@ -600,6 +625,7 @@ genfs_getpages(void *v)
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}
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}
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if (i == npages) {
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lockmgr(&gp->g_glock, LK_RELEASE, NULL);
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UVMHIST_LOG(ubchist, "returning cached pages", 0,0,0,0);
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npages += ridx;
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goto out;
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@ -610,6 +636,7 @@ genfs_getpages(void *v)
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*/
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if (overwrite) {
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lockmgr(&gp->g_glock, LK_RELEASE, NULL);
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UVMHIST_LOG(ubchist, "PGO_OVERWRITE",0,0,0,0);
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for (i = 0; i < npages; i++) {
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@ -644,6 +671,7 @@ genfs_getpages(void *v)
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npgs = npages;
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if (uvn_findpages(uobj, startoffset, &npgs, pgs,
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async ? UFP_NOWAIT : UFP_ALL) != npages) {
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lockmgr(&gp->g_glock, LK_RELEASE, NULL);
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KASSERT(async != 0);
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genfs_rel_pages(pgs, npages);
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simple_unlock(&uobj->vmobjlock);
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@ -700,12 +728,6 @@ genfs_getpages(void *v)
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* now loop over the pages, reading as needed.
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*/
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if (blockalloc) {
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lockmgr(&gp->g_glock, LK_EXCLUSIVE, NULL);
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} else {
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lockmgr(&gp->g_glock, LK_SHARED, NULL);
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}
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bp = NULL;
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for (offset = startoffset;
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bytes > 0;
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@ -1,4 +1,4 @@
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/* $NetBSD: uvm_vnode.c,v 1.71 2006/07/21 16:48:54 ad Exp $ */
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/* $NetBSD: uvm_vnode.c,v 1.72 2006/07/22 08:47:56 yamt Exp $ */
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/*
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* Copyright (c) 1997 Charles D. Cranor and Washington University.
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@ -50,7 +50,7 @@
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.71 2006/07/21 16:48:54 ad Exp $");
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__KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.72 2006/07/22 08:47:56 yamt Exp $");
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#include "fs_nfs.h"
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#include "opt_uvmhist.h"
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@ -482,6 +482,7 @@ uvm_vnp_setsize(struct vnode *vp, voff_t newsize)
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{
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struct uvm_object *uobj = &vp->v_uobj;
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voff_t pgend = round_page(newsize);
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voff_t oldsize;
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UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist);
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simple_lock(&uobj->vmobjlock);
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@ -493,12 +494,13 @@ uvm_vnp_setsize(struct vnode *vp, voff_t newsize)
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* toss some pages...
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*/
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if (vp->v_size > pgend && vp->v_size != VSIZENOTSET) {
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oldsize = vp->v_size;
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vp->v_size = newsize;
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if (oldsize > pgend && oldsize != VSIZENOTSET) {
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(void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO);
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} else {
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simple_unlock(&uobj->vmobjlock);
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}
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vp->v_size = newsize;
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}
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/*
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