a0595d0249
locking flags when acquiring a vnode. The immediate purpose is to allow polling lock requests (LK_NOWAIT) needed by soft updates to avoid deadlock when enlisting other processes to help with the background cleanup. For the future it will allow the use of shared locks for read access to vnodes. This change touches a lot of files as it affects most filesystems within the system. It has been well tested on FFS, loopback, and CD-ROM filesystems. only lightly on the others, so if you find a problem there, please let me (mckusick@mckusick.com) know.
428 lines
11 KiB
C
428 lines
11 KiB
C
/*
|
|
* Copyright (c) 1992, 1993, 1995
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software donated to Berkeley by
|
|
* Jan-Simon Pendry.
|
|
*
|
|
* 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 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.
|
|
*
|
|
* @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
|
|
*
|
|
* @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* Null Layer
|
|
* (See null_vnops.c for a description of what this does.)
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mount.h>
|
|
#include <sys/namei.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/vnode.h>
|
|
|
|
#include <fs/nullfs/null.h>
|
|
|
|
static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
|
|
|
|
static int nullfs_fhtovp(struct mount *mp, struct fid *fidp,
|
|
struct vnode **vpp);
|
|
static int nullfs_checkexp(struct mount *mp, struct sockaddr *nam,
|
|
int *extflagsp, struct ucred **credanonp);
|
|
static int nullfs_mount(struct mount *mp, char *path, caddr_t data,
|
|
struct nameidata *ndp, struct thread *td);
|
|
static int nullfs_quotactl(struct mount *mp, int cmd, uid_t uid,
|
|
caddr_t arg, struct thread *td);
|
|
static int nullfs_root(struct mount *mp, struct vnode **vpp);
|
|
static int nullfs_start(struct mount *mp, int flags, struct thread *td);
|
|
static int nullfs_statfs(struct mount *mp, struct statfs *sbp,
|
|
struct thread *td);
|
|
static int nullfs_sync(struct mount *mp, int waitfor,
|
|
struct ucred *cred, struct thread *td);
|
|
static int nullfs_unmount(struct mount *mp, int mntflags, struct thread *td);
|
|
static int nullfs_vget(struct mount *mp, ino_t ino, int flags,
|
|
struct vnode **vpp);
|
|
static int nullfs_vptofh(struct vnode *vp, struct fid *fhp);
|
|
static int nullfs_extattrctl(struct mount *mp, int cmd,
|
|
struct vnode *filename_vp,
|
|
int namespace, const char *attrname,
|
|
struct thread *td);
|
|
|
|
/*
|
|
* Mount null layer
|
|
*/
|
|
static int
|
|
nullfs_mount(mp, path, data, ndp, td)
|
|
struct mount *mp;
|
|
char *path;
|
|
caddr_t data;
|
|
struct nameidata *ndp;
|
|
struct thread *td;
|
|
{
|
|
int error = 0;
|
|
struct null_args args;
|
|
struct vnode *lowerrootvp, *vp;
|
|
struct vnode *nullm_rootvp;
|
|
struct null_mount *xmp;
|
|
size_t size;
|
|
int isvnunlocked = 0;
|
|
|
|
NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
|
|
|
|
/*
|
|
* Update is a no-op
|
|
*/
|
|
if (mp->mnt_flag & MNT_UPDATE) {
|
|
return (EOPNOTSUPP);
|
|
/* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/
|
|
}
|
|
|
|
/*
|
|
* Get argument
|
|
*/
|
|
error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* Unlock lower node to avoid deadlock.
|
|
* (XXX) VOP_ISLOCKED is needed?
|
|
*/
|
|
if ((mp->mnt_vnodecovered->v_op == null_vnodeop_p) &&
|
|
VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
|
|
VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
|
|
isvnunlocked = 1;
|
|
}
|
|
/*
|
|
* Find lower node
|
|
*/
|
|
NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
|
|
UIO_USERSPACE, args.target, td);
|
|
error = namei(ndp);
|
|
/*
|
|
* Re-lock vnode.
|
|
*/
|
|
if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
|
|
vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
|
|
|
|
if (error)
|
|
return (error);
|
|
NDFREE(ndp, NDF_ONLY_PNBUF);
|
|
|
|
/*
|
|
* Sanity check on lower vnode
|
|
*/
|
|
lowerrootvp = ndp->ni_vp;
|
|
|
|
vrele(ndp->ni_dvp);
|
|
ndp->ni_dvp = NULLVP;
|
|
|
|
/*
|
|
* Check multi null mount to avoid `lock against myself' panic.
|
|
*/
|
|
if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
|
|
NULLFSDEBUG("nullfs_mount: multi null mount?\n");
|
|
vput(lowerrootvp);
|
|
return (EDEADLK);
|
|
}
|
|
|
|
xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
|
|
M_NULLFSMNT, M_WAITOK); /* XXX */
|
|
|
|
/*
|
|
* Save reference to underlying FS
|
|
*/
|
|
xmp->nullm_vfs = lowerrootvp->v_mount;
|
|
|
|
/*
|
|
* Save reference. Each mount also holds
|
|
* a reference on the root vnode.
|
|
*/
|
|
error = null_node_create(mp, lowerrootvp, &vp);
|
|
/*
|
|
* Unlock the node (either the lower or the alias)
|
|
*/
|
|
VOP_UNLOCK(vp, 0, td);
|
|
/*
|
|
* Make sure the node alias worked
|
|
*/
|
|
if (error) {
|
|
vrele(lowerrootvp);
|
|
free(xmp, M_NULLFSMNT); /* XXX */
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Keep a held reference to the root vnode.
|
|
* It is vrele'd in nullfs_unmount.
|
|
*/
|
|
nullm_rootvp = vp;
|
|
nullm_rootvp->v_flag |= VROOT;
|
|
xmp->nullm_rootvp = nullm_rootvp;
|
|
if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
|
|
mp->mnt_flag |= MNT_LOCAL;
|
|
mp->mnt_data = (qaddr_t) xmp;
|
|
vfs_getnewfsid(mp);
|
|
|
|
(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname,
|
|
MNAMELEN - 1, &size);
|
|
bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
|
|
(void)nullfs_statfs(mp, &mp->mnt_stat, td);
|
|
NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
|
|
mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* VFS start. Nothing needed here - the start routine
|
|
* on the underlying filesystem will have been called
|
|
* when that filesystem was mounted.
|
|
*/
|
|
static int
|
|
nullfs_start(mp, flags, td)
|
|
struct mount *mp;
|
|
int flags;
|
|
struct thread *td;
|
|
{
|
|
return (0);
|
|
/* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, td); */
|
|
}
|
|
|
|
/*
|
|
* Free reference to null layer
|
|
*/
|
|
static int
|
|
nullfs_unmount(mp, mntflags, td)
|
|
struct mount *mp;
|
|
int mntflags;
|
|
struct thread *td;
|
|
{
|
|
void *mntdata;
|
|
int error;
|
|
int flags = 0;
|
|
|
|
NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
|
|
|
|
if (mntflags & MNT_FORCE)
|
|
flags |= FORCECLOSE;
|
|
|
|
/* There is 1 extra root vnode reference (nullm_rootvp). */
|
|
error = vflush(mp, 1, flags);
|
|
if (error)
|
|
return (error);
|
|
|
|
/*
|
|
* Finally, throw away the null_mount structure
|
|
*/
|
|
mntdata = mp->mnt_data;
|
|
mp->mnt_data = 0;
|
|
free(mntdata, M_NULLFSMNT);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
nullfs_root(mp, vpp)
|
|
struct mount *mp;
|
|
struct vnode **vpp;
|
|
{
|
|
struct thread *td = curthread; /* XXX */
|
|
struct vnode *vp;
|
|
|
|
NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
|
|
(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
|
|
(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
|
|
|
|
/*
|
|
* Return locked reference to root.
|
|
*/
|
|
vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
|
|
VREF(vp);
|
|
|
|
#ifdef NULLFS_DEBUG
|
|
if (VOP_ISLOCKED(vp, NULL)) {
|
|
Debugger("root vnode is locked.\n");
|
|
vrele(vp);
|
|
return (EDEADLK);
|
|
}
|
|
#endif
|
|
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
|
|
*vpp = vp;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
nullfs_quotactl(mp, cmd, uid, arg, td)
|
|
struct mount *mp;
|
|
int cmd;
|
|
uid_t uid;
|
|
caddr_t arg;
|
|
struct thread *td;
|
|
{
|
|
return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
|
|
}
|
|
|
|
static int
|
|
nullfs_statfs(mp, sbp, td)
|
|
struct mount *mp;
|
|
struct statfs *sbp;
|
|
struct thread *td;
|
|
{
|
|
int error;
|
|
struct statfs mstat;
|
|
|
|
NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
|
|
(void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
|
|
(void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
|
|
|
|
bzero(&mstat, sizeof(mstat));
|
|
|
|
error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
|
|
if (error)
|
|
return (error);
|
|
|
|
/* now copy across the "interesting" information and fake the rest */
|
|
sbp->f_type = mstat.f_type;
|
|
sbp->f_flags = mstat.f_flags;
|
|
sbp->f_bsize = mstat.f_bsize;
|
|
sbp->f_iosize = mstat.f_iosize;
|
|
sbp->f_blocks = mstat.f_blocks;
|
|
sbp->f_bfree = mstat.f_bfree;
|
|
sbp->f_bavail = mstat.f_bavail;
|
|
sbp->f_files = mstat.f_files;
|
|
sbp->f_ffree = mstat.f_ffree;
|
|
if (sbp != &mp->mnt_stat) {
|
|
bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
|
|
bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
|
|
bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
nullfs_sync(mp, waitfor, cred, td)
|
|
struct mount *mp;
|
|
int waitfor;
|
|
struct ucred *cred;
|
|
struct thread *td;
|
|
{
|
|
/*
|
|
* XXX - Assumes no data cached at null layer.
|
|
*/
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
nullfs_vget(mp, ino, flags, vpp)
|
|
struct mount *mp;
|
|
ino_t ino;
|
|
int flags;
|
|
struct vnode **vpp;
|
|
{
|
|
int error;
|
|
error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
|
|
if (error)
|
|
return (error);
|
|
|
|
return (null_node_create(mp, *vpp, vpp));
|
|
}
|
|
|
|
static int
|
|
nullfs_fhtovp(mp, fidp, vpp)
|
|
struct mount *mp;
|
|
struct fid *fidp;
|
|
struct vnode **vpp;
|
|
{
|
|
int error;
|
|
error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
|
|
if (error)
|
|
return (error);
|
|
|
|
return (null_node_create(mp, *vpp, vpp));
|
|
}
|
|
|
|
static int
|
|
nullfs_checkexp(mp, nam, extflagsp, credanonp)
|
|
struct mount *mp;
|
|
struct sockaddr *nam;
|
|
int *extflagsp;
|
|
struct ucred **credanonp;
|
|
{
|
|
|
|
return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
|
|
extflagsp, credanonp);
|
|
}
|
|
|
|
static int
|
|
nullfs_vptofh(vp, fhp)
|
|
struct vnode *vp;
|
|
struct fid *fhp;
|
|
{
|
|
return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
|
|
}
|
|
|
|
static int
|
|
nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td)
|
|
struct mount *mp;
|
|
int cmd;
|
|
struct vnode *filename_vp;
|
|
int namespace;
|
|
const char *attrname;
|
|
struct thread *td;
|
|
{
|
|
return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
|
|
namespace, attrname, td);
|
|
}
|
|
|
|
|
|
static struct vfsops null_vfsops = {
|
|
nullfs_mount,
|
|
nullfs_start,
|
|
nullfs_unmount,
|
|
nullfs_root,
|
|
nullfs_quotactl,
|
|
nullfs_statfs,
|
|
nullfs_sync,
|
|
nullfs_vget,
|
|
nullfs_fhtovp,
|
|
nullfs_checkexp,
|
|
nullfs_vptofh,
|
|
nullfs_init,
|
|
nullfs_uninit,
|
|
nullfs_extattrctl,
|
|
};
|
|
|
|
VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);
|