NetBSD/sys/fs/smbfs/smbfs_kq.c

508 lines
13 KiB
C

/* $NetBSD: smbfs_kq.c,v 1.7 2003/06/29 22:31:12 fvdl Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jaromir Dolecek.
*
* 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 NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: smbfs_kq.c,v 1.7 2003/06/29 22:31:12 fvdl Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/fcntl.h>
#include <sys/mount.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/lockf.h>
#include <sys/malloc.h>
#include <sys/kthread.h>
#include <sys/file.h>
#include <sys/dirent.h>
#include <machine/limits.h>
#include <uvm/uvm.h>
#include <uvm/uvm_extern.h>
#include <netsmb/smb.h>
#include <netsmb/smb_conn.h>
#include <netsmb/smb_subr.h>
#include <netsmb/smb_rq.h>
#include <fs/smbfs/smbfs.h>
#include <fs/smbfs/smbfs_node.h>
#include <fs/smbfs/smbfs_subr.h>
#include <miscfs/genfs/genfs.h>
/*
* The maximum of outstanding SMB requests is 65536, since the
* message id is 16bit. Don't consume all. If there is more
* than 30k directory notify requests, fall back to polling mode.
*/
#define DNOTIFY_MAX 30000
struct kevq {
SLIST_ENTRY(kevq) kev_link; /* link on kevlist */
SLIST_ENTRY(kevq) k_link; /* link on poll/dn list */
struct vnode *vp;
u_int usecount;
u_int flags;
#define KEVQ_BUSY 0x01 /* currently being processed */
#define KEVQ_WANT 0x02 /* want to change this entry */
#define KEVQ_DNOT 0x04 /* kevent using NT directory change notify */
struct timespec omtime; /* old modification time */
struct timespec octime; /* old change time */
nlink_t onlink; /* old number of references to file */
struct smb_rq *rq; /* request structure */
};
static struct proc *smbkqp; /* the kevent handler */
static struct smb_cred smbkq_scred;
static struct simplelock smbkq_lock = SIMPLELOCK_INITIALIZER;
/* guard access to k*evlist */
static SLIST_HEAD(, kevq) kevlist = SLIST_HEAD_INITIALIZER(kevlist);
static SLIST_HEAD(, kevq) kplist = SLIST_HEAD_INITIALIZER(kplist);
static SLIST_HEAD(, kevq) kdnlist = SLIST_HEAD_INITIALIZER(kdnlist);
static int dnot_num = 0; /* number of active dir notifications */
static u_int32_t kevs;
static void smbfskq_dirnotify(void *);
/*
* This routine periodically checks server for change
* of any of the watched files every SMBFS_MINATTRTIME/2 seconds.
* Only changes in size, modification time, change time and nlinks
* are being checked, everything else is ignored.
* Directory events are watched via NT DIRECTORY CHANGE NOTIFY
* if the server supports it.
*
* The routine only calls VOP_GETATTR() when it's likely it would get
* some new data, i.e. when the vnode expires from attrcache. This
* should give same result as periodically running stat(2) from userland,
* while keeping CPU/network usage low, and still provide proper kevent
* semantics.
* The poller thread is created when first vnode is added to watch list,
* and exits when the watch list is empty. The overhead of thread creation
* isn't really important, neither speed of attach and detach of knote.
*/
/* ARGSUSED */
static void
smbfs_kqpoll(void *arg)
{
struct kevq *ke;
struct vattr attr;
int error=0;
struct proc *p = smbkqp;
u_quad_t osize;
int needwake;
simple_lock(&smbkq_lock);
for(;;) {
/* check all entries on poll list for changes */
SLIST_FOREACH(ke, &kplist, k_link) {
/* skip if still in attrcache */
if (smbfs_attr_cachelookup(ke->vp, &attr) != ENOENT)
continue;
/*
* Mark entry busy, release lock and check
* for changes.
*/
ke->flags |= KEVQ_BUSY;
simple_unlock(&smbkq_lock);
/* save v_size, smbfs_getattr() updates it */
osize = ke->vp->v_size;
error = VOP_GETATTR(ke->vp, &attr, p->p_ucred, p);
if (error) {
/* relock and proceed with next */
simple_lock(&smbkq_lock);
continue;
}
/* following is a bit fragile, but about best
* we can get */
if (ke->vp->v_type != VDIR && attr.va_size != osize) {
int extended = (attr.va_size > osize);
VN_KNOTE(ke->vp, NOTE_WRITE
| (extended ? NOTE_EXTEND : 0));
ke->omtime = attr.va_mtime;
} else if (attr.va_mtime.tv_sec != ke->omtime.tv_sec
|| attr.va_mtime.tv_nsec != ke->omtime.tv_nsec) {
VN_KNOTE(ke->vp, NOTE_WRITE);
ke->omtime = attr.va_mtime;
}
if (attr.va_ctime.tv_sec != ke->octime.tv_sec
|| attr.va_ctime.tv_nsec != ke->octime.tv_nsec) {
VN_KNOTE(ke->vp, NOTE_ATTRIB);
ke->octime = attr.va_ctime;
}
if (attr.va_nlink != ke->onlink) {
VN_KNOTE(ke->vp, NOTE_LINK);
ke->onlink = attr.va_nlink;
}
simple_lock(&smbkq_lock);
ke->flags &= ~KEVQ_BUSY;
if (ke->flags & KEVQ_WANT) {
ke->flags &= ~KEVQ_WANT;
wakeup(ke);
}
}
/* Exit if there are no more kevents to watch for */
if (kevs == 0) {
smbkqp = NULL;
break;
}
/* only wake periodically if poll list is nonempty */
needwake = !SLIST_EMPTY(&kplist);
/* wait a while before checking for changes again */
if (SLIST_EMPTY(&kdnlist)) {
error = ltsleep(smbkqp, PSOCK, "smbkqidl",
needwake ? (SMBFS_ATTRTIMO * hz / 2) : 0,
&smbkq_lock);
}
if (!error) {
/* woken up, check if any pending notifications */
while (!SLIST_EMPTY(&kdnlist)) {
int s, hint;
s = splnet();
ke = SLIST_FIRST(&kdnlist);
SLIST_REMOVE_HEAD(&kdnlist, k_link);
SLIST_NEXT(ke, k_link) = NULL;
splx(s);
/* drop lock while processing */
simple_unlock(&smbkq_lock);
/*
* Skip fetch if not yet setup.
*/
if (__predict_false(ke->rq == NULL))
goto notifyrq;
error = smbfs_smb_nt_dirnotify_fetch(ke->rq,
&hint);
ke->rq = NULL; /* rq deallocated by now */
if (error) {
/*
* if there is error, switch to
* polling for this one
*/
ke->flags &= KEVQ_DNOT;
SLIST_INSERT_HEAD(&kplist, ke, k_link);
continue;
}
VN_KNOTE(ke->vp, hint);
notifyrq:
/* reissue the notify request */
(void) smbfs_smb_nt_dirnotify_setup(
VTOSMB(ke->vp),
&ke->rq, &smbkq_scred,
smbfskq_dirnotify, ke);
/* reacquire the lock */
simple_lock(&smbkq_lock);
}
}
}
simple_unlock(&smbkq_lock);
kthread_exit(0);
}
static void
smbfskq_dirnotify(void *arg)
{
struct kevq *ke = arg;
if (SLIST_NEXT(ke, k_link)) {
/* already on notify list */
return;
}
SLIST_INSERT_HEAD(&kdnlist, ke, k_link);
wakeup(smbkqp);
}
static void
filt_smbfsdetach(struct knote *kn)
{
struct kevq *ke = (struct kevq *)kn->kn_hook;
struct smb_rq *rq = NULL;
/* XXXLUKEM lock the struct? */
SLIST_REMOVE(&ke->vp->v_klist, kn, knote, kn_selnext);
/* Remove the vnode from watch list */
simple_lock(&smbkq_lock);
/* the handler does something to it, wait */
while (ke->flags & KEVQ_BUSY) {
ke->flags |= KEVQ_WANT;
ltsleep(ke, PSOCK, "smbkqdw", 0, &smbkq_lock);
}
if (ke->usecount > 1) {
/* keep, other kevents need this */
ke->usecount--;
} else {
/* last user, g/c */
if (ke->flags & KEVQ_DNOT) {
dnot_num--;
rq = ke->rq;
/* If on dirnotify list, remove */
if (SLIST_NEXT(ke, k_link))
SLIST_REMOVE(&kdnlist, ke, kevq, k_link);
} else
SLIST_REMOVE(&kplist, ke, kevq, k_link);
SLIST_REMOVE(&kevlist, ke, kevq, kev_link);
FREE(ke, M_KEVENT);
}
kevs--;
simple_unlock(&smbkq_lock);
/* If there was request still pending, cancel it now */
if (rq) {
smb_iod_removerq(rq);
/*
* Explicitly cancel the request, so that server can
* free directory change notify resources.
*/
smbfs_smb_ntcancel(SSTOCP(rq->sr_share), rq->sr_mid,
&smbkq_scred);
/* Free */
smb_rq_done(rq);
}
}
static int
filt_smbfsread(struct knote *kn, long hint)
{
struct kevq *ke = (struct kevq *)kn->kn_hook;
struct vnode *vp = ke->vp;
/*
* filesystem is gone, so set the EOF flag and schedule
* the knote for deletion.
*/
if (hint == NOTE_REVOKE) {
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
return (1);
}
/* There is no size info for directories */
if (vp->v_type == VDIR) {
/*
* This is kind of hackish, since we need to
* set the flag when we are called with the hint
* to make confirming call from kern_event.c
* succeed too, but need to unset it afterwards
* so that the directory wouldn't stay flagged
* as changed.
* XXX perhaps just fail for directories?
*/
if (hint & NOTE_WRITE) {
kn->kn_fflags |= NOTE_WRITE;
return (1 * sizeof(struct dirent));
} else if (hint == 0 && (kn->kn_fflags & NOTE_WRITE)) {
kn->kn_fflags &= ~NOTE_WRITE;
return (1 * sizeof(struct dirent));
} else
return (0);
}
/* XXXLUKEM lock the struct? */
kn->kn_data = vp->v_size - kn->kn_fp->f_offset;
return (kn->kn_data != 0);
}
static int
filt_smbfsvnode(struct knote *kn, long hint)
{
if (kn->kn_sfflags & hint)
kn->kn_fflags |= hint;
if (hint == NOTE_REVOKE) {
kn->kn_flags |= EV_EOF;
return (1);
}
return (kn->kn_fflags != 0);
}
static const struct filterops smbfsread_filtops =
{ 1, NULL, filt_smbfsdetach, filt_smbfsread };
static const struct filterops smbfsvnode_filtops =
{ 1, NULL, filt_smbfsdetach, filt_smbfsvnode };
int
smbfs_kqfilter(void *v)
{
struct vop_kqfilter_args /* {
struct vnode *a_vp;
struct knote *a_kn;
} */ *ap = v;
struct vnode *vp = ap->a_vp;
struct knote *kn = ap->a_kn;
struct kevq *ke, *ken;
int error = 0;
struct vattr attr;
struct proc *p = curproc; /* XXX */
int dnot;
struct smb_vc *vcp = SSTOVC(VTOSMB(vp)->n_mount->sm_share);
switch (kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &smbfsread_filtops;
break;
case EVFILT_VNODE:
kn->kn_fop = &smbfsvnode_filtops;
break;
default:
return (1);
}
/* Find out if we can use directory change notify for this file */
dnot = (vp->v_type == VDIR
&& (SMB_CAPS(vcp) & SMB_CAP_NT_SMBS)
&& dnot_num < DNOTIFY_MAX);
/*
* Put the vnode to watched list.
*/
kevs++;
/*
* Fetch current attributes. It's only needed when the vnode
* is not watched yet, but we need to do this without lock
* held. This is likely cheap due to attrcache, so do it now.
*/
memset(&attr, 0, sizeof(attr));
(void) VOP_GETATTR(vp, &attr, p->p_ucred, p);
/* ensure the handler is running */
if (!smbkqp) {
error = kthread_create1(smbfs_kqpoll, NULL, &smbkqp,
"smbkq");
smb_makescred(&smbkq_scred, smbkqp, smbkqp->p_ucred);
if (error) {
kevs--;
return (error);
}
}
/*
* Allocate new kev. It's more probable it will be needed,
* and the malloc is cheaper than scanning possibly
* large kevlist list second time after malloc.
*/
MALLOC(ken, struct kevq *, sizeof(struct kevq), M_KEVENT, M_WAITOK);
/* Check the list and insert new entry */
simple_lock(&smbkq_lock);
SLIST_FOREACH(ke, &kevlist, kev_link) {
if (ke->vp == vp)
break;
}
if (ke) {
/* already watched, so just bump usecount */
ke->usecount++;
FREE(ken, M_KEVENT); /* dispose, don't need */
} else {
/* need a new one */
memset(ken, 0, sizeof(*ken));
ke = ken;
ke->vp = vp;
ke->usecount = 1;
ke->flags = (dnot) ? KEVQ_DNOT : 0;
ke->omtime = attr.va_mtime;
ke->octime = attr.va_ctime;
ke->onlink = attr.va_nlink;
if (dnot) {
int s;
/*
* Add kevent to list of 'need attend' kevnets.
* The handler will pick it up and setup request
* appropriately.
*/
s = splnet();
SLIST_INSERT_HEAD(&kdnlist, ke, k_link);
splx(s);
dnot_num++;
} else {
/* add to poll list */
SLIST_INSERT_HEAD(&kplist, ke, k_link);
}
SLIST_INSERT_HEAD(&kevlist, ke, kev_link);
/* kick the handler */
wakeup(smbkqp);
}
/* XXXLUKEM lock the struct? */
SLIST_INSERT_HEAD(&vp->v_klist, kn, kn_selnext);
kn->kn_hook = ke;
simple_unlock(&smbkq_lock);
return (0);
}