freebsd-dev/sys/nfsclient/nfs_node.c
Rick Macklem 8f63187ec1 Add LK_NOWITNESS to the vn_lock() calls done on newly created nfs
vnodes, since these nodes are not linked into the mount queue and,
as such, the vn_lock() cannot cause a deadlock so LORs are harmless.

Suggested by:	kib
Approved by:	kib (mentor)
MFC after:	3 days
2009-09-09 20:37:49 +00:00

263 lines
6.5 KiB
C

/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)nfs_node.c 8.6 (Berkeley) 5/22/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fnv_hash.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/vnode.h>
#include <vm/uma.h>
#include <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfsclient/nfsnode.h>
#include <nfsclient/nfsmount.h>
static uma_zone_t nfsnode_zone;
#define TRUE 1
#define FALSE 0
void
nfs_nhinit(void)
{
nfsnode_zone = uma_zcreate("NFSNODE", sizeof(struct nfsnode), NULL,
NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
}
void
nfs_nhuninit(void)
{
uma_zdestroy(nfsnode_zone);
}
struct nfs_vncmp {
int fhsize;
void *fh;
};
static int
nfs_vncmpf(struct vnode *vp, void *arg)
{
struct nfs_vncmp *a;
struct nfsnode *np;
a = arg;
np = VTONFS(vp);
return (bcmp(a->fh, np->n_fhp, a->fhsize));
}
/*
* Look up a vnode/nfsnode by file handle.
* Callers must check for mount points!!
* In all cases, a pointer to a
* nfsnode structure is returned.
*/
int
nfs_nget(struct mount *mntp, nfsfh_t *fhp, int fhsize, struct nfsnode **npp, int flags)
{
struct thread *td = curthread; /* XXX */
struct nfsnode *np;
struct vnode *vp;
struct vnode *nvp;
int error;
u_int hash;
struct nfsmount *nmp;
struct nfs_vncmp ncmp;
nmp = VFSTONFS(mntp);
*npp = NULL;
hash = fnv_32_buf(fhp->fh_bytes, fhsize, FNV1_32_INIT);
ncmp.fhsize = fhsize;
ncmp.fh = fhp;
error = vfs_hash_get(mntp, hash, flags,
td, &nvp, nfs_vncmpf, &ncmp);
if (error)
return (error);
if (nvp != NULL) {
*npp = VTONFS(nvp);
return (0);
}
/*
* Allocate before getnewvnode since doing so afterward
* might cause a bogus v_data pointer to get dereferenced
* elsewhere if zalloc should block.
*/
np = uma_zalloc(nfsnode_zone, M_WAITOK | M_ZERO);
error = getnewvnode("nfs", mntp, &nfs_vnodeops, &nvp);
if (error) {
uma_zfree(nfsnode_zone, np);
return (error);
}
vp = nvp;
vp->v_bufobj.bo_ops = &buf_ops_nfs;
vp->v_data = np;
np->n_vnode = vp;
/*
* Initialize the mutex even if the vnode is going to be a loser.
* This simplifies the logic in reclaim, which can then unconditionally
* destroy the mutex (in the case of the loser, or if hash_insert happened
* to return an error no special casing is needed).
*/
mtx_init(&np->n_mtx, "NFSnode lock", NULL, MTX_DEF);
/*
* NFS supports recursive and shared locking.
*/
VN_LOCK_AREC(vp);
VN_LOCK_ASHARE(vp);
if (fhsize > NFS_SMALLFH) {
np->n_fhp = malloc(fhsize, M_NFSBIGFH, M_WAITOK);
} else
np->n_fhp = &np->n_fh;
bcopy((caddr_t)fhp, (caddr_t)np->n_fhp, fhsize);
np->n_fhsize = fhsize;
lockmgr(vp->v_vnlock, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
error = insmntque(vp, mntp);
if (error != 0) {
*npp = NULL;
if (np->n_fhsize > NFS_SMALLFH) {
free((caddr_t)np->n_fhp, M_NFSBIGFH);
}
mtx_destroy(&np->n_mtx);
uma_zfree(nfsnode_zone, np);
return (error);
}
error = vfs_hash_insert(vp, hash, flags,
td, &nvp, nfs_vncmpf, &ncmp);
if (error)
return (error);
if (nvp != NULL) {
*npp = VTONFS(nvp);
/* vfs_hash_insert() vput()'s the losing vnode */
return (0);
}
*npp = np;
return (0);
}
int
nfs_inactive(struct vop_inactive_args *ap)
{
struct nfsnode *np;
struct sillyrename *sp;
struct thread *td = curthread; /* XXX */
np = VTONFS(ap->a_vp);
if (prtactive && vrefcnt(ap->a_vp) != 0)
vprint("nfs_inactive: pushing active", ap->a_vp);
if (ap->a_vp->v_type != VDIR) {
sp = np->n_sillyrename;
np->n_sillyrename = NULL;
} else
sp = NULL;
if (sp) {
(void)nfs_vinvalbuf(ap->a_vp, 0, td, 1);
/*
* Remove the silly file that was rename'd earlier
*/
(sp->s_removeit)(sp);
crfree(sp->s_cred);
vrele(sp->s_dvp);
free((caddr_t)sp, M_NFSREQ);
}
np->n_flag &= NMODIFIED;
return (0);
}
/*
* Reclaim an nfsnode so that it can be used for other purposes.
*/
int
nfs_reclaim(struct vop_reclaim_args *ap)
{
struct vnode *vp = ap->a_vp;
struct nfsnode *np = VTONFS(vp);
struct nfsdmap *dp, *dp2;
if (prtactive && vrefcnt(vp) != 0)
vprint("nfs_reclaim: pushing active", vp);
/*
* If the NLM is running, give it a chance to abort pending
* locks.
*/
if (nfs_reclaim_p)
nfs_reclaim_p(ap);
/*
* Destroy the vm object and flush associated pages.
*/
vnode_destroy_vobject(vp);
vfs_hash_remove(vp);
/*
* Free up any directory cookie structures and
* large file handle structures that might be associated with
* this nfs node.
*/
if (vp->v_type == VDIR) {
dp = LIST_FIRST(&np->n_cookies);
while (dp) {
dp2 = dp;
dp = LIST_NEXT(dp, ndm_list);
free((caddr_t)dp2, M_NFSDIROFF);
}
}
if (np->n_fhsize > NFS_SMALLFH) {
free((caddr_t)np->n_fhp, M_NFSBIGFH);
}
mtx_destroy(&np->n_mtx);
uma_zfree(nfsnode_zone, vp->v_data);
vp->v_data = NULL;
return (0);
}