/*      $NetBSD: nfs_clsubs.c,v 1.2 2016/12/13 22:17:33 pgoyette Exp $  */
/*-
* 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.
*
*      from nfs_subs.c  8.8 (Berkeley) 5/22/95
*/

#include <sys/cdefs.h>
/* __FBSDID("FreeBSD: head/sys/fs/nfsclient/nfs_clsubs.c 304026 2016-08-12 22:44:59Z rmacklem "); */
__RCSID("$NetBSD: nfs_clsubs.c,v 1.2 2016/12/13 22:17:33 pgoyette Exp $");

/*
* These functions support the macros and help fiddle mbuf chains for
* the nfs op functions. They do things like create the rpc header and
* copy data between mbuf chains and uio lists.
*/

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <sys/sysent.h>
#include <sys/syscall.h>
#include <sys/sysproto.h>
#include <sys/taskqueue.h>

#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>

#include <fs/nfs/common/nfsport.h>
#include <fs/nfs/client/nfsnode.h>
#include <fs/nfs/client/nfsmount.h>
#include <fs/nfs/client/nfs.h>
#include <fs/nfs/client/nfs_kdtrace.h>

#include <netinet/in.h>

/*
* Note that stdarg.h and the ANSI style va_start macro is used for both
* ANSI and traditional C compilers.
*/
#include <machine/stdarg.h>

extern struct mtx ncl_iod_mutex;
extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
extern int ncl_numasync;
extern unsigned int ncl_iodmax;
extern struct nfsstatsv1 nfsstatsv1;

struct task     ncl_nfsiodnew_task;

int
ncl_uninit(struct vfsconf *vfsp)
{
       /*
        * XXX: Unloading of nfscl module is unsupported.
        */
#if 0
       int i;

       /*
        * Tell all nfsiod processes to exit. Clear ncl_iodmax, and wakeup
        * any sleeping nfsiods so they check ncl_iodmax and exit.
        */
       mtx_lock(&ncl_iod_mutex);
       ncl_iodmax = 0;
       for (i = 0; i < ncl_numasync; i++)
               if (ncl_iodwant[i] == NFSIOD_AVAILABLE)
                       wakeup(&ncl_iodwant[i]);
       /* The last nfsiod to exit will wake us up when ncl_numasync hits 0 */
       while (ncl_numasync)
               msleep(&ncl_numasync, &ncl_iod_mutex, PWAIT, "ioddie", 0);
       mtx_unlock(&ncl_iod_mutex);
       ncl_nhuninit();
       return (0);
#else
       return (EOPNOTSUPP);
#endif
}

void
ncl_dircookie_lock(struct nfsnode *np)
{
       mtx_lock(&np->n_mtx);
       while (np->n_flag & NDIRCOOKIELK)
               (void) msleep(&np->n_flag, &np->n_mtx, PZERO, "nfsdirlk", 0);
       np->n_flag |= NDIRCOOKIELK;
       mtx_unlock(&np->n_mtx);
}

void
ncl_dircookie_unlock(struct nfsnode *np)
{
       mtx_lock(&np->n_mtx);
       np->n_flag &= ~NDIRCOOKIELK;
       wakeup(&np->n_flag);
       mtx_unlock(&np->n_mtx);
}

int
ncl_upgrade_vnlock(struct vnode *vp)
{
       int old_lock;

       ASSERT_VOP_LOCKED(vp, "ncl_upgrade_vnlock");
       old_lock = NFSVOPISLOCKED(vp);
       if (old_lock != LK_EXCLUSIVE) {
               KASSERT(old_lock == LK_SHARED,
                   ("ncl_upgrade_vnlock: wrong old_lock %d", old_lock));
               /* Upgrade to exclusive lock, this might block */
               NFSVOPLOCK(vp, LK_UPGRADE | LK_RETRY);
       }
       return (old_lock);
}

void
ncl_downgrade_vnlock(struct vnode *vp, int old_lock)
{
       if (old_lock != LK_EXCLUSIVE) {
               KASSERT(old_lock == LK_SHARED, ("wrong old_lock %d", old_lock));
               /* Downgrade from exclusive lock. */
               NFSVOPLOCK(vp, LK_DOWNGRADE | LK_RETRY);
       }
}

#ifdef NFS_ACDEBUG
#include <sys/sysctl.h>
SYSCTL_DECL(_vfs_nfs);
static int nfs_acdebug;
SYSCTL_INT(_vfs_nfs, OID_AUTO, acdebug, CTLFLAG_RW, &nfs_acdebug, 0, "");
#endif

/*
* Check the time stamp
* If the cache is valid, copy contents to *vap and return 0
* otherwise return an error
*/
int
ncl_getattrcache(struct vnode *vp, struct vattr *vaper)
{
       struct nfsnode *np;
       struct vattr *vap;
       struct nfsmount *nmp;
       int timeo, mustflush;

       np = VTONFS(vp);
       vap = &np->n_vattr.na_vattr;
       nmp = VFSTONFS(vp->v_mount);
       mustflush = nfscl_mustflush(vp);        /* must be before mtx_lock() */
       mtx_lock(&np->n_mtx);
       /* XXX n_mtime doesn't seem to be updated on a miss-and-reload */
       timeo = (time_second - np->n_mtime.tv_sec) / 10;

#ifdef NFS_ACDEBUG
       if (nfs_acdebug>1)
               printf("ncl_getattrcache: initial timeo = %d\n", timeo);
#endif

       if (vap->va_type == VDIR) {
               if ((np->n_flag & NMODIFIED) || timeo < nmp->nm_acdirmin)
                       timeo = nmp->nm_acdirmin;
               else if (timeo > nmp->nm_acdirmax)
                       timeo = nmp->nm_acdirmax;
       } else {
               if ((np->n_flag & NMODIFIED) || timeo < nmp->nm_acregmin)
                       timeo = nmp->nm_acregmin;
               else if (timeo > nmp->nm_acregmax)
                       timeo = nmp->nm_acregmax;
       }

#ifdef NFS_ACDEBUG
       if (nfs_acdebug > 2)
               printf("acregmin %d; acregmax %d; acdirmin %d; acdirmax %d\n",
                   nmp->nm_acregmin, nmp->nm_acregmax,
                   nmp->nm_acdirmin, nmp->nm_acdirmax);

       if (nfs_acdebug)
               printf("ncl_getattrcache: age = %d; final timeo = %d\n",
                   (time_second - np->n_attrstamp), timeo);
#endif

       if ((time_second - np->n_attrstamp) >= timeo &&
           (mustflush != 0 || np->n_attrstamp == 0)) {
               nfsstatsv1.attrcache_misses++;
               mtx_unlock(&np->n_mtx);
               KDTRACE_NFS_ATTRCACHE_GET_MISS(vp);
               return( ENOENT);
       }
       nfsstatsv1.attrcache_hits++;
       if (vap->va_size != np->n_size) {
               if (vap->va_type == VREG) {
                       if (np->n_flag & NMODIFIED) {
                               if (vap->va_size < np->n_size)
                                       vap->va_size = np->n_size;
                               else
                                       np->n_size = vap->va_size;
                       } else {
                               np->n_size = vap->va_size;
                       }
                       vnode_pager_setsize(vp, np->n_size);
               } else {
                       np->n_size = vap->va_size;
               }
       }
       bcopy((caddr_t)vap, (caddr_t)vaper, sizeof(struct vattr));
       if (np->n_flag & NCHG) {
               if (np->n_flag & NACC)
                       vaper->va_atime = np->n_atim;
               if (np->n_flag & NUPD)
                       vaper->va_mtime = np->n_mtim;
       }
       mtx_unlock(&np->n_mtx);
       KDTRACE_NFS_ATTRCACHE_GET_HIT(vp, vap);
       return (0);
}

static nfsuint64 nfs_nullcookie = { { 0, 0 } };
/*
* This function finds the directory cookie that corresponds to the
* logical byte offset given.
*/
nfsuint64 *
ncl_getcookie(struct nfsnode *np, off_t off, int add)
{
       struct nfsdmap *dp, *dp2;
       int pos;
       nfsuint64 *retval = NULL;

       pos = (uoff_t)off / NFS_DIRBLKSIZ;
       if (pos == 0 || off < 0) {
               KASSERT(!add, ("nfs getcookie add at <= 0"));
               return (&nfs_nullcookie);
       }
       pos--;
       dp = LIST_FIRST(&np->n_cookies);
       if (!dp) {
               if (add) {
                       MALLOC(dp, struct nfsdmap *, sizeof (struct nfsdmap),
                               M_NFSDIROFF, M_WAITOK);
                       dp->ndm_eocookie = 0;
                       LIST_INSERT_HEAD(&np->n_cookies, dp, ndm_list);
               } else
                       goto out;
       }
       while (pos >= NFSNUMCOOKIES) {
               pos -= NFSNUMCOOKIES;
               if (LIST_NEXT(dp, ndm_list)) {
                       if (!add && dp->ndm_eocookie < NFSNUMCOOKIES &&
                           pos >= dp->ndm_eocookie)
                               goto out;
                       dp = LIST_NEXT(dp, ndm_list);
               } else if (add) {
                       MALLOC(dp2, struct nfsdmap *, sizeof (struct nfsdmap),
                               M_NFSDIROFF, M_WAITOK);
                       dp2->ndm_eocookie = 0;
                       LIST_INSERT_AFTER(dp, dp2, ndm_list);
                       dp = dp2;
               } else
                       goto out;
       }
       if (pos >= dp->ndm_eocookie) {
               if (add)
                       dp->ndm_eocookie = pos + 1;
               else
                       goto out;
       }
       retval = &dp->ndm_cookies[pos];
out:
       return (retval);
}

/*
* Invalidate cached directory information, except for the actual directory
* blocks (which are invalidated separately).
* Done mainly to avoid the use of stale offset cookies.
*/
void
ncl_invaldir(struct vnode *vp)
{
       struct nfsnode *np = VTONFS(vp);

       KASSERT(vp->v_type == VDIR, ("nfs: invaldir not dir"));
       ncl_dircookie_lock(np);
       np->n_direofoffset = 0;
       np->n_cookieverf.nfsuquad[0] = 0;
       np->n_cookieverf.nfsuquad[1] = 0;
       if (LIST_FIRST(&np->n_cookies))
               LIST_FIRST(&np->n_cookies)->ndm_eocookie = 0;
       ncl_dircookie_unlock(np);
}

/*
* The write verifier has changed (probably due to a server reboot), so all
* B_NEEDCOMMIT blocks will have to be written again. Since they are on the
* dirty block list as B_DELWRI, all this takes is clearing the B_NEEDCOMMIT
* and B_CLUSTEROK flags.  Once done the new write verifier can be set for the
* mount point.
*
* B_CLUSTEROK must be cleared along with B_NEEDCOMMIT because stage 1 data
* writes are not clusterable.
*/
void
ncl_clearcommit(struct mount *mp)
{
       struct vnode *vp, *nvp;
       struct buf *bp, *nbp;
       struct bufobj *bo;

       MNT_VNODE_FOREACH_ALL(vp, mp, nvp) {
               bo = &vp->v_bufobj;
               vholdl(vp);
               VI_UNLOCK(vp);
               BO_LOCK(bo);
               TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
                       if (!BUF_ISLOCKED(bp) &&
                           (bp->b_flags & (B_DELWRI | B_NEEDCOMMIT))
                               == (B_DELWRI | B_NEEDCOMMIT))
                               bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
               }
               BO_UNLOCK(bo);
               vdrop(vp);
       }
}

/*
* Called once to initialize data structures...
*/
int
ncl_init(struct vfsconf *vfsp)
{
       int i;

       /* Ensure async daemons disabled */
       for (i = 0; i < NFS_MAXASYNCDAEMON; i++) {
               ncl_iodwant[i] = NFSIOD_NOT_AVAILABLE;
               ncl_iodmount[i] = NULL;
       }
       TASK_INIT(&ncl_nfsiodnew_task, 0, ncl_nfsiodnew_tq, NULL);
       ncl_nhinit();                   /* Init the nfsnode table */

       return (0);
}