FreeBSD-5.3/sys/kern/vfs_default.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 John Heidemann of the UCLA Ficus project.
*
* Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/vfs_default.c,v 1.97 2004/07/12 08:14:08 alfred Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/poll.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vnode_pager.h>
static int vop_nolookup(struct vop_lookup_args *);
static int vop_nostrategy(struct vop_strategy_args *);
/*
* This vnode table stores what we want to do if the filesystem doesn't
* implement a particular VOP.
*
* If there is no specific entry here, we will return EOPNOTSUPP.
*
*/
vop_t **default_vnodeop_p;
static struct vnodeopv_entry_desc default_vnodeop_entries[] = {
{ &vop_default_desc, (vop_t *) vop_eopnotsupp },
{ &vop_advlock_desc, (vop_t *) vop_einval },
{ &vop_bmap_desc, (vop_t *) vop_stdbmap },
{ &vop_close_desc, (vop_t *) vop_null },
{ &vop_createvobject_desc, (vop_t *) vop_stdcreatevobject },
{ &vop_destroyvobject_desc, (vop_t *) vop_stddestroyvobject },
{ &vop_fsync_desc, (vop_t *) vop_null },
{ &vop_getpages_desc, (vop_t *) vop_stdgetpages },
{ &vop_getvobject_desc, (vop_t *) vop_stdgetvobject },
{ &vop_inactive_desc, (vop_t *) vop_stdinactive },
{ &vop_ioctl_desc, (vop_t *) vop_enotty },
{ &vop_islocked_desc, (vop_t *) vop_stdislocked },
{ &vop_lease_desc, (vop_t *) vop_null },
{ &vop_lock_desc, (vop_t *) vop_stdlock },
{ &vop_lookup_desc, (vop_t *) vop_nolookup },
{ &vop_open_desc, (vop_t *) vop_null },
{ &vop_pathconf_desc, (vop_t *) vop_einval },
{ &vop_poll_desc, (vop_t *) vop_nopoll },
{ &vop_putpages_desc, (vop_t *) vop_stdputpages },
{ &vop_readlink_desc, (vop_t *) vop_einval },
{ &vop_revoke_desc, (vop_t *) vop_revoke },
{ &vop_specstrategy_desc, (vop_t *) vop_panic },
{ &vop_strategy_desc, (vop_t *) vop_nostrategy },
{ &vop_unlock_desc, (vop_t *) vop_stdunlock },
{ NULL, NULL }
};
static struct vnodeopv_desc default_vnodeop_opv_desc =
{ &default_vnodeop_p, default_vnodeop_entries };
VNODEOP_SET(default_vnodeop_opv_desc);
/*
* Series of placeholder functions for various error returns for
* VOPs.
*/
int
vop_eopnotsupp(struct vop_generic_args *ap)
{
/*
printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
*/
return (EOPNOTSUPP);
}
int
vop_ebadf(struct vop_generic_args *ap)
{
return (EBADF);
}
int
vop_enotty(struct vop_generic_args *ap)
{
return (ENOTTY);
}
int
vop_einval(struct vop_generic_args *ap)
{
return (EINVAL);
}
int
vop_null(struct vop_generic_args *ap)
{
return (0);
}
/*
* Used to make a defined VOP fall back to the default VOP.
*/
int
vop_defaultop(struct vop_generic_args *ap)
{
return (VOCALL(default_vnodeop_p, ap->a_desc->vdesc_offset, ap));
}
/*
* Helper function to panic on some bad VOPs in some filesystems.
*/
int
vop_panic(struct vop_generic_args *ap)
{
panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
}
/*
* vop_std<something> and vop_no<something> are default functions for use by
* filesystems that need the "default reasonable" implementation for a
* particular operation.
*
* The documentation for the operations they implement exists (if it exists)
* in the VOP_<SOMETHING>(9) manpage (all uppercase).
*/
/*
* Default vop for filesystems that do not support name lookup
*/
static int
vop_nolookup(ap)
struct vop_lookup_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
*ap->a_vpp = NULL;
return (ENOTDIR);
}
/*
* vop_nostrategy:
*
* Strategy routine for VFS devices that have none.
*
* BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
* routine. Typically this is done for a BIO_READ strategy call.
* Typically B_INVAL is assumed to already be clear prior to a write
* and should not be cleared manually unless you just made the buffer
* invalid. BIO_ERROR should be cleared either way.
*/
static int
vop_nostrategy (struct vop_strategy_args *ap)
{
KASSERT(ap->a_vp == ap->a_bp->b_vp, ("%s(%p != %p)",
__func__, ap->a_vp, ap->a_bp->b_vp));
printf("No strategy for buffer at %p\n", ap->a_bp);
vprint("vnode", ap->a_vp);
vprint("device vnode", ap->a_bp->b_vp);
ap->a_bp->b_ioflags |= BIO_ERROR;
ap->a_bp->b_error = EOPNOTSUPP;
bufdone(ap->a_bp);
return (EOPNOTSUPP);
}
/*
* vop_stdpathconf:
*
* Standard implementation of POSIX pathconf, to get information about limits
* for a filesystem.
* Override per filesystem for the case where the filesystem has smaller
* limits.
*/
int
vop_stdpathconf(ap)
struct vop_pathconf_args /* {
struct vnode *a_vp;
int a_name;
int *a_retval;
} */ *ap;
{
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = LINK_MAX;
return (0);
case _PC_MAX_CANON:
*ap->a_retval = MAX_CANON;
return (0);
case _PC_MAX_INPUT:
*ap->a_retval = MAX_INPUT;
return (0);
case _PC_PIPE_BUF:
*ap->a_retval = PIPE_BUF;
return (0);
case _PC_CHOWN_RESTRICTED:
*ap->a_retval = 1;
return (0);
case _PC_VDISABLE:
*ap->a_retval = _POSIX_VDISABLE;
return (0);
default:
return (EINVAL);
}
/* NOTREACHED */
}
/*
* Standard lock, unlock and islocked functions.
*/
int
vop_stdlock(ap)
struct vop_lock_args /* {
struct vnode *a_vp;
int a_flags;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
#ifndef DEBUG_LOCKS
return (lockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp), ap->a_td));
#else
return (debuglockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
ap->a_td, "vop_stdlock", vp->filename, vp->line));
#endif
}
/* See above. */
int
vop_stdunlock(ap)
struct vop_unlock_args /* {
struct vnode *a_vp;
int a_flags;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp),
ap->a_td));
}
/* See above. */
int
vop_stdislocked(ap)
struct vop_islocked_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
return (lockstatus(ap->a_vp->v_vnlock, ap->a_td));
}
/* Mark the vnode inactive */
int
vop_stdinactive(ap)
struct vop_inactive_args /* {
struct vnode *a_vp;
struct thread *a_td;
} */ *ap;
{
VOP_UNLOCK(ap->a_vp, 0, ap->a_td);
return (0);
}
/*
* Return true for select/poll.
*/
int
vop_nopoll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
/*
* Return true for read/write. If the user asked for something
* special, return POLLNVAL, so that clients have a way of
* determining reliably whether or not the extended
* functionality is present without hard-coding knowledge
* of specific filesystem implementations.
* Stay in sync with kern_conf.c::no_poll().
*/
if (ap->a_events & ~POLLSTANDARD)
return (POLLNVAL);
return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
/*
* Implement poll for local filesystems that support it.
*/
int
vop_stdpoll(ap)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
struct ucred *a_cred;
struct thread *a_td;
} */ *ap;
{
if (ap->a_events & ~POLLSTANDARD)
return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
/*
* Return our mount point, as we will take charge of the writes.
*/
int
vop_stdgetwritemount(ap)
struct vop_getwritemount_args /* {
struct vnode *a_vp;
struct mount **a_mpp;
} */ *ap;
{
*(ap->a_mpp) = ap->a_vp->v_mount;
return (0);
}
/* Create the VM system backing object for this vnode */
int
vop_stdcreatevobject(ap)
struct vop_createvobject_args /* {
struct vnode *vp;
struct ucred *cred;
struct thread *td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct ucred *cred = ap->a_cred;
struct thread *td = ap->a_td;
struct vattr vat;
vm_object_t object;
int error = 0;
GIANT_REQUIRED;
if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
return (0);
retry:
if ((object = vp->v_object) == NULL) {
if (vp->v_type == VREG || vp->v_type == VDIR) {
if ((error = VOP_GETATTR(vp, &vat, cred, td)) != 0)
goto retn;
object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
} else if (devsw(vp->v_rdev) != NULL) {
/*
* This simply allocates the biggest object possible
* for a disk vnode. This should be fixed, but doesn't
* cause any problems (yet).
*/
object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
} else {
goto retn;
}
/*
* Dereference the reference we just created. This assumes
* that the object is associated with the vp.
*/
VM_OBJECT_LOCK(object);
object->ref_count--;
VM_OBJECT_UNLOCK(object);
vrele(vp);
} else {
VM_OBJECT_LOCK(object);
if (object->flags & OBJ_DEAD) {
VOP_UNLOCK(vp, 0, td);
msleep(object, VM_OBJECT_MTX(object), PDROP | PVM,
"vodead", 0);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
goto retry;
}
VM_OBJECT_UNLOCK(object);
}
KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
vp->v_vflag |= VV_OBJBUF;
retn:
return (error);
}
/* Destroy the VM system object associated with this vnode */
int
vop_stddestroyvobject(ap)
struct vop_destroyvobject_args /* {
struct vnode *vp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
vm_object_t obj = vp->v_object;
GIANT_REQUIRED;
if (obj == NULL)
return (0);
VM_OBJECT_LOCK(obj);
if (obj->ref_count == 0) {
/*
* vclean() may be called twice. The first time
* removes the primary reference to the object,
* the second time goes one further and is a
* special-case to terminate the object.
*
* don't double-terminate the object
*/
if ((obj->flags & OBJ_DEAD) == 0)
vm_object_terminate(obj);
else
VM_OBJECT_UNLOCK(obj);
} else {
/*
* Woe to the process that tries to page now :-).
*/
vm_pager_deallocate(obj);
VM_OBJECT_UNLOCK(obj);
}
return (0);
}
/*
* Return the underlying VM object. This routine may be called with or
* without the vnode interlock held. If called without, the returned
* object is not guarenteed to be valid. The syncer typically gets the
* object without holding the interlock in order to quickly test whether
* it might be dirty before going heavy-weight. vm_object's use zalloc
* and thus stable-storage, so this is safe.
*/
int
vop_stdgetvobject(ap)
struct vop_getvobject_args /* {
struct vnode *vp;
struct vm_object **objpp;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct vm_object **objpp = ap->a_objpp;
if (objpp)
*objpp = vp->v_object;
return (vp->v_object ? 0 : EINVAL);
}
/* XXX Needs good comment and VOP_BMAP(9) manpage */
int
vop_stdbmap(ap)
struct vop_bmap_args /* {
struct vnode *a_vp;
daddr_t a_bn;
struct vnode **a_vpp;
daddr_t *a_bnp;
int *a_runp;
int *a_runb;
} */ *ap;
{
if (ap->a_vpp != NULL)
*ap->a_vpp = ap->a_vp;
if (ap->a_bnp != NULL)
*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
if (ap->a_runp != NULL)
*ap->a_runp = 0;
if (ap->a_runb != NULL)
*ap->a_runb = 0;
return (0);
}
int
vop_stdfsync(ap)
struct vop_fsync_args /* {
struct vnode *a_vp;
struct ucred *a_cred;
int a_waitfor;
struct thread *a_td;
} */ *ap;
{
struct vnode *vp = ap->a_vp;
struct buf *bp;
struct buf *nbp;
int s, error = 0;
int maxretry = 100; /* large, arbitrarily chosen */
VI_LOCK(vp);
loop1:
/*
* MARK/SCAN initialization to avoid infinite loops.
*/
s = splbio();
TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs) {
bp->b_vflags &= ~BV_SCANNED;
bp->b_error = 0;
}
splx(s);
/*
* Flush all dirty buffers associated with a block device.
*/
loop2:
s = splbio();
for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp != NULL; bp = nbp) {
nbp = TAILQ_NEXT(bp, b_vnbufs);
if ((bp->b_vflags & BV_SCANNED) != 0)
continue;
bp->b_vflags |= BV_SCANNED;
if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL))
continue;
VI_UNLOCK(vp);
if ((bp->b_flags & B_DELWRI) == 0)
panic("fsync: not dirty");
if ((vp->v_vflag & VV_OBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
vfs_bio_awrite(bp);
splx(s);
} else {
bremfree(bp);
splx(s);
bawrite(bp);
}
VI_LOCK(vp);
goto loop2;
}
/*
* If synchronous the caller expects us to completely resolve all
* dirty buffers in the system. Wait for in-progress I/O to
* complete (which could include background bitmap writes), then
* retry if dirty blocks still exist.
*/
if (ap->a_waitfor == MNT_WAIT) {
while (vp->v_numoutput) {
vp->v_iflag |= VI_BWAIT;
msleep((caddr_t)&vp->v_numoutput, VI_MTX(vp),
PRIBIO + 1, "fsync", 0);
}
if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
/*
* If we are unable to write any of these buffers
* then we fail now rather than trying endlessly
* to write them out.
*/
TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs)
if ((error = bp->b_error) == 0)
continue;
if (error == 0 && --maxretry >= 0) {
splx(s);
goto loop1;
}
vprint("fsync: giving up on dirty", vp);
error = EAGAIN;
}
}
VI_UNLOCK(vp);
splx(s);
return (error);
}
/* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
int
vop_stdgetpages(ap)
struct vop_getpages_args /* {
struct vnode *a_vp;
vm_page_t *a_m;
int a_count;
int a_reqpage;
vm_ooffset_t a_offset;
} */ *ap;
{
return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
ap->a_count, ap->a_reqpage);
}
/* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
int
vop_stdputpages(ap)
struct vop_putpages_args /* {
struct vnode *a_vp;
vm_page_t *a_m;
int a_count;
int a_sync;
int *a_rtvals;
vm_ooffset_t a_offset;
} */ *ap;
{
return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_sync, ap->a_rtvals);
}
/*
* vfs default ops
* used to fill the vfs function table to get reasonable default return values.
*/
int
vfs_stdroot (mp, vpp, td)
struct mount *mp;
struct vnode **vpp;
struct thread *td;
{
return (EOPNOTSUPP);
}
int
vfs_stdstatfs (mp, sbp, td)
struct mount *mp;
struct statfs *sbp;
struct thread *td;
{
return (EOPNOTSUPP);
}
int
vfs_stdvptofh (vp, fhp)
struct vnode *vp;
struct fid *fhp;
{
return (EOPNOTSUPP);
}
int
vfs_stdstart (mp, flags, td)
struct mount *mp;
int flags;
struct thread *td;
{
return (0);
}
int
vfs_stdquotactl (mp, cmds, uid, arg, td)
struct mount *mp;
int cmds;
uid_t uid;
caddr_t arg;
struct thread *td;
{
return (EOPNOTSUPP);
}
int
vfs_stdsync(mp, waitfor, cred, td)
struct mount *mp;
int waitfor;
struct ucred *cred;
struct thread *td;
{
struct vnode *vp, *nvp;
int error, lockreq, allerror = 0;
lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
if (waitfor != MNT_WAIT)
lockreq |= LK_NOWAIT;
/*
* Force stale buffer cache information to be flushed.
*/
MNT_ILOCK(mp);
loop:
MNT_VNODE_FOREACH(vp, mp, nvp) {
VI_LOCK(vp);
if (TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
VI_UNLOCK(vp);
continue;
}
MNT_IUNLOCK(mp);
if ((error = vget(vp, lockreq, td)) != 0) {
MNT_ILOCK(mp);
if (error == ENOENT)
goto loop;
continue;
}
error = VOP_FSYNC(vp, cred, waitfor, td);
if (error)
allerror = error;
VOP_UNLOCK(vp, 0, td);
vrele(vp);
MNT_ILOCK(mp);
}
MNT_IUNLOCK(mp);
return (allerror);
}
int
vfs_stdnosync (mp, waitfor, cred, td)
struct mount *mp;
int waitfor;
struct ucred *cred;
struct thread *td;
{
return (0);
}
int
vfs_stdvget (mp, ino, flags, vpp)
struct mount *mp;
ino_t ino;
int flags;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
vfs_stdfhtovp (mp, fhp, vpp)
struct mount *mp;
struct fid *fhp;
struct vnode **vpp;
{
return (EOPNOTSUPP);
}
int
vfs_stdinit (vfsp)
struct vfsconf *vfsp;
{
return (0);
}
int
vfs_stduninit (vfsp)
struct vfsconf *vfsp;
{
return(0);
}
int
vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname, td)
struct mount *mp;
int cmd;
struct vnode *filename_vp;
int attrnamespace;
const char *attrname;
struct thread *td;
{
if (filename_vp != NULL)
VOP_UNLOCK(filename_vp, 0, td);
return (EOPNOTSUPP);
}
int
vfs_stdsysctl(mp, op, req)
struct mount *mp;
fsctlop_t op;
struct sysctl_req *req;
{
return (EOPNOTSUPP);
}
/* end of vfs default ops */