The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/fs/nfsclient/nfs_clbio.c

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    1 /*-
    2  * Copyright (c) 1989, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * This code is derived from software contributed to Berkeley by
    6  * Rick Macklem at The University of Guelph.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 4. Neither the name of the University nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  *      @(#)nfs_bio.c   8.9 (Berkeley) 3/30/95
   33  */
   34 
   35 #include <sys/cdefs.h>
   36 __FBSDID("$FreeBSD: releng/8.1/sys/fs/nfsclient/nfs_clbio.c 207406 2010-04-29 23:48:09Z rmacklem $");
   37 
   38 #include <sys/param.h>
   39 #include <sys/systm.h>
   40 #include <sys/bio.h>
   41 #include <sys/buf.h>
   42 #include <sys/kernel.h>
   43 #include <sys/mount.h>
   44 #include <sys/proc.h>
   45 #include <sys/resourcevar.h>
   46 #include <sys/signalvar.h>
   47 #include <sys/vmmeter.h>
   48 #include <sys/vnode.h>
   49 
   50 #include <vm/vm.h>
   51 #include <vm/vm_extern.h>
   52 #include <vm/vm_page.h>
   53 #include <vm/vm_object.h>
   54 #include <vm/vm_pager.h>
   55 #include <vm/vnode_pager.h>
   56 
   57 #include <fs/nfs/nfsport.h>
   58 #include <fs/nfsclient/nfsmount.h>
   59 #include <fs/nfsclient/nfs.h>
   60 #include <fs/nfsclient/nfsnode.h>
   61 
   62 extern int newnfs_directio_allow_mmap;
   63 extern struct nfsstats newnfsstats;
   64 extern struct mtx ncl_iod_mutex;
   65 extern int ncl_numasync;
   66 extern enum nfsiod_state ncl_iodwant[NFS_MAXRAHEAD];
   67 extern struct nfsmount *ncl_iodmount[NFS_MAXRAHEAD];
   68 extern int newnfs_directio_enable;
   69 
   70 int ncl_pbuf_freecnt = -1;      /* start out unlimited */
   71 
   72 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
   73     struct thread *td);
   74 static int nfs_directio_write(struct vnode *vp, struct uio *uiop, 
   75     struct ucred *cred, int ioflag);
   76 
   77 /*
   78  * Vnode op for VM getpages.
   79  */
   80 int
   81 ncl_getpages(struct vop_getpages_args *ap)
   82 {
   83         int i, error, nextoff, size, toff, count, npages;
   84         struct uio uio;
   85         struct iovec iov;
   86         vm_offset_t kva;
   87         struct buf *bp;
   88         struct vnode *vp;
   89         struct thread *td;
   90         struct ucred *cred;
   91         struct nfsmount *nmp;
   92         vm_object_t object;
   93         vm_page_t *pages;
   94         struct nfsnode *np;
   95 
   96         vp = ap->a_vp;
   97         np = VTONFS(vp);
   98         td = curthread;                         /* XXX */
   99         cred = curthread->td_ucred;             /* XXX */
  100         nmp = VFSTONFS(vp->v_mount);
  101         pages = ap->a_m;
  102         count = ap->a_count;
  103 
  104         if ((object = vp->v_object) == NULL) {
  105                 ncl_printf("nfs_getpages: called with non-merged cache vnode??\n");
  106                 return (VM_PAGER_ERROR);
  107         }
  108 
  109         if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
  110                 mtx_lock(&np->n_mtx);
  111                 if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  112                         mtx_unlock(&np->n_mtx);
  113                         ncl_printf("nfs_getpages: called on non-cacheable vnode??\n");
  114                         return (VM_PAGER_ERROR);
  115                 } else
  116                         mtx_unlock(&np->n_mtx);
  117         }
  118 
  119         mtx_lock(&nmp->nm_mtx);
  120         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  121             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {  
  122                 mtx_unlock(&nmp->nm_mtx);
  123                 /* We'll never get here for v4, because we always have fsinfo */
  124                 (void)ncl_fsinfo(nmp, vp, cred, td);
  125         } else
  126                 mtx_unlock(&nmp->nm_mtx);
  127 
  128         npages = btoc(count);
  129 
  130         /*
  131          * If the requested page is partially valid, just return it and
  132          * allow the pager to zero-out the blanks.  Partially valid pages
  133          * can only occur at the file EOF.
  134          */
  135         VM_OBJECT_LOCK(object);
  136         if (pages[ap->a_reqpage]->valid != 0) {
  137                 vm_page_lock_queues();
  138                 for (i = 0; i < npages; ++i) {
  139                         if (i != ap->a_reqpage)
  140                                 vm_page_free(pages[i]);
  141                 }
  142                 vm_page_unlock_queues();
  143                 VM_OBJECT_UNLOCK(object);
  144                 return (0);
  145         }
  146         VM_OBJECT_UNLOCK(object);
  147 
  148         /*
  149          * We use only the kva address for the buffer, but this is extremely
  150          * convienient and fast.
  151          */
  152         bp = getpbuf(&ncl_pbuf_freecnt);
  153 
  154         kva = (vm_offset_t) bp->b_data;
  155         pmap_qenter(kva, pages, npages);
  156         PCPU_INC(cnt.v_vnodein);
  157         PCPU_ADD(cnt.v_vnodepgsin, npages);
  158 
  159         iov.iov_base = (caddr_t) kva;
  160         iov.iov_len = count;
  161         uio.uio_iov = &iov;
  162         uio.uio_iovcnt = 1;
  163         uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
  164         uio.uio_resid = count;
  165         uio.uio_segflg = UIO_SYSSPACE;
  166         uio.uio_rw = UIO_READ;
  167         uio.uio_td = td;
  168 
  169         error = ncl_readrpc(vp, &uio, cred);
  170         pmap_qremove(kva, npages);
  171 
  172         relpbuf(bp, &ncl_pbuf_freecnt);
  173 
  174         if (error && (uio.uio_resid == count)) {
  175                 ncl_printf("nfs_getpages: error %d\n", error);
  176                 VM_OBJECT_LOCK(object);
  177                 vm_page_lock_queues();
  178                 for (i = 0; i < npages; ++i) {
  179                         if (i != ap->a_reqpage)
  180                                 vm_page_free(pages[i]);
  181                 }
  182                 vm_page_unlock_queues();
  183                 VM_OBJECT_UNLOCK(object);
  184                 return (VM_PAGER_ERROR);
  185         }
  186 
  187         /*
  188          * Calculate the number of bytes read and validate only that number
  189          * of bytes.  Note that due to pending writes, size may be 0.  This
  190          * does not mean that the remaining data is invalid!
  191          */
  192 
  193         size = count - uio.uio_resid;
  194         VM_OBJECT_LOCK(object);
  195         vm_page_lock_queues();
  196         for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
  197                 vm_page_t m;
  198                 nextoff = toff + PAGE_SIZE;
  199                 m = pages[i];
  200 
  201                 if (nextoff <= size) {
  202                         /*
  203                          * Read operation filled an entire page
  204                          */
  205                         m->valid = VM_PAGE_BITS_ALL;
  206                         KASSERT(m->dirty == 0,
  207                             ("nfs_getpages: page %p is dirty", m));
  208                 } else if (size > toff) {
  209                         /*
  210                          * Read operation filled a partial page.
  211                          */
  212                         m->valid = 0;
  213                         vm_page_set_valid(m, 0, size - toff);
  214                         KASSERT(m->dirty == 0,
  215                             ("nfs_getpages: page %p is dirty", m));
  216                 } else {
  217                         /*
  218                          * Read operation was short.  If no error occured
  219                          * we may have hit a zero-fill section.   We simply
  220                          * leave valid set to 0.
  221                          */
  222                         ;
  223                 }
  224                 if (i != ap->a_reqpage) {
  225                         /*
  226                          * Whether or not to leave the page activated is up in
  227                          * the air, but we should put the page on a page queue
  228                          * somewhere (it already is in the object).  Result:
  229                          * It appears that emperical results show that
  230                          * deactivating pages is best.
  231                          */
  232 
  233                         /*
  234                          * Just in case someone was asking for this page we
  235                          * now tell them that it is ok to use.
  236                          */
  237                         if (!error) {
  238                                 if (m->oflags & VPO_WANTED)
  239                                         vm_page_activate(m);
  240                                 else
  241                                         vm_page_deactivate(m);
  242                                 vm_page_wakeup(m);
  243                         } else {
  244                                 vm_page_free(m);
  245                         }
  246                 }
  247         }
  248         vm_page_unlock_queues();
  249         VM_OBJECT_UNLOCK(object);
  250         return (0);
  251 }
  252 
  253 /*
  254  * Vnode op for VM putpages.
  255  */
  256 int
  257 ncl_putpages(struct vop_putpages_args *ap)
  258 {
  259         struct uio uio;
  260         struct iovec iov;
  261         vm_offset_t kva;
  262         struct buf *bp;
  263         int iomode, must_commit, i, error, npages, count;
  264         off_t offset;
  265         int *rtvals;
  266         struct vnode *vp;
  267         struct thread *td;
  268         struct ucred *cred;
  269         struct nfsmount *nmp;
  270         struct nfsnode *np;
  271         vm_page_t *pages;
  272 
  273         vp = ap->a_vp;
  274         np = VTONFS(vp);
  275         td = curthread;                         /* XXX */
  276         cred = curthread->td_ucred;             /* XXX */
  277         nmp = VFSTONFS(vp->v_mount);
  278         pages = ap->a_m;
  279         count = ap->a_count;
  280         rtvals = ap->a_rtvals;
  281         npages = btoc(count);
  282         offset = IDX_TO_OFF(pages[0]->pindex);
  283         
  284         mtx_lock(&nmp->nm_mtx);
  285         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  286             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  287                 mtx_unlock(&nmp->nm_mtx);
  288                 (void)ncl_fsinfo(nmp, vp, cred, td);
  289         } else
  290                 mtx_unlock(&nmp->nm_mtx);
  291 
  292         mtx_lock(&np->n_mtx);
  293         if (newnfs_directio_enable && !newnfs_directio_allow_mmap && 
  294             (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  295                 mtx_unlock(&np->n_mtx);         
  296                 ncl_printf("ncl_putpages: called on noncache-able vnode??\n");
  297                 mtx_lock(&np->n_mtx);
  298         }
  299 
  300         for (i = 0; i < npages; i++)
  301                 rtvals[i] = VM_PAGER_AGAIN;
  302 
  303         /*
  304          * When putting pages, do not extend file past EOF.
  305          */
  306         if (offset + count > np->n_size) {
  307                 count = np->n_size - offset;
  308                 if (count < 0)
  309                         count = 0;
  310         }
  311         mtx_unlock(&np->n_mtx);
  312 
  313         /*
  314          * We use only the kva address for the buffer, but this is extremely
  315          * convienient and fast.
  316          */
  317         bp = getpbuf(&ncl_pbuf_freecnt);
  318 
  319         kva = (vm_offset_t) bp->b_data;
  320         pmap_qenter(kva, pages, npages);
  321         PCPU_INC(cnt.v_vnodeout);
  322         PCPU_ADD(cnt.v_vnodepgsout, count);
  323 
  324         iov.iov_base = (caddr_t) kva;
  325         iov.iov_len = count;
  326         uio.uio_iov = &iov;
  327         uio.uio_iovcnt = 1;
  328         uio.uio_offset = offset;
  329         uio.uio_resid = count;
  330         uio.uio_segflg = UIO_SYSSPACE;
  331         uio.uio_rw = UIO_WRITE;
  332         uio.uio_td = td;
  333 
  334         if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
  335             iomode = NFSWRITE_UNSTABLE;
  336         else
  337             iomode = NFSWRITE_FILESYNC;
  338 
  339         error = ncl_writerpc(vp, &uio, cred, &iomode, &must_commit, 0);
  340 
  341         pmap_qremove(kva, npages);
  342         relpbuf(bp, &ncl_pbuf_freecnt);
  343 
  344         if (!error) {
  345                 int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
  346                 for (i = 0; i < nwritten; i++) {
  347                         rtvals[i] = VM_PAGER_OK;
  348                         vm_page_undirty(pages[i]);
  349                 }
  350                 if (must_commit) {
  351                         ncl_clearcommit(vp->v_mount);
  352                 }
  353         }
  354         return rtvals[0];
  355 }
  356 
  357 /*
  358  * For nfs, cache consistency can only be maintained approximately.
  359  * Although RFC1094 does not specify the criteria, the following is
  360  * believed to be compatible with the reference port.
  361  * For nfs:
  362  * If the file's modify time on the server has changed since the
  363  * last read rpc or you have written to the file,
  364  * you may have lost data cache consistency with the
  365  * server, so flush all of the file's data out of the cache.
  366  * Then force a getattr rpc to ensure that you have up to date
  367  * attributes.
  368  * NB: This implies that cache data can be read when up to
  369  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
  370  * attributes this could be forced by setting n_attrstamp to 0 before
  371  * the VOP_GETATTR() call.
  372  */
  373 static inline int
  374 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
  375 {
  376         int error = 0;
  377         struct vattr vattr;
  378         struct nfsnode *np = VTONFS(vp);
  379         int old_lock;
  380         
  381         /*
  382          * Grab the exclusive lock before checking whether the cache is
  383          * consistent.
  384          * XXX - We can make this cheaper later (by acquiring cheaper locks).
  385          * But for now, this suffices.
  386          */
  387         old_lock = ncl_upgrade_vnlock(vp);
  388         if (vp->v_iflag & VI_DOOMED) {
  389                 ncl_downgrade_vnlock(vp, old_lock);
  390                 return (EBADF);
  391         }
  392 
  393         mtx_lock(&np->n_mtx);
  394         if (np->n_flag & NMODIFIED) {
  395                 mtx_unlock(&np->n_mtx);
  396                 if (vp->v_type != VREG) {
  397                         if (vp->v_type != VDIR)
  398                                 panic("nfs: bioread, not dir");
  399                         ncl_invaldir(vp);
  400                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  401                         if (error)
  402                                 goto out;
  403                 }
  404                 np->n_attrstamp = 0;
  405                 error = VOP_GETATTR(vp, &vattr, cred);
  406                 if (error)
  407                         goto out;
  408                 mtx_lock(&np->n_mtx);
  409                 np->n_mtime = vattr.va_mtime;
  410                 mtx_unlock(&np->n_mtx);
  411         } else {
  412                 mtx_unlock(&np->n_mtx);
  413                 error = VOP_GETATTR(vp, &vattr, cred);
  414                 if (error)
  415                         return (error);
  416                 mtx_lock(&np->n_mtx);
  417                 if ((np->n_flag & NSIZECHANGED)
  418                     || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
  419                         mtx_unlock(&np->n_mtx);
  420                         if (vp->v_type == VDIR)
  421                                 ncl_invaldir(vp);
  422                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  423                         if (error)
  424                                 goto out;
  425                         mtx_lock(&np->n_mtx);
  426                         np->n_mtime = vattr.va_mtime;
  427                         np->n_flag &= ~NSIZECHANGED;
  428                 }
  429                 mtx_unlock(&np->n_mtx);
  430         }
  431 out:    
  432         ncl_downgrade_vnlock(vp, old_lock);
  433         return error;
  434 }
  435 
  436 /*
  437  * Vnode op for read using bio
  438  */
  439 int
  440 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
  441 {
  442         struct nfsnode *np = VTONFS(vp);
  443         int biosize, i;
  444         struct buf *bp, *rabp;
  445         struct thread *td;
  446         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  447         daddr_t lbn, rabn;
  448         int bcount;
  449         int seqcount;
  450         int nra, error = 0, n = 0, on = 0;
  451 
  452 #ifdef DIAGNOSTIC
  453         if (uio->uio_rw != UIO_READ)
  454                 panic("ncl_read mode");
  455 #endif
  456         if (uio->uio_resid == 0)
  457                 return (0);
  458         if (uio->uio_offset < 0)        /* XXX VDIR cookies can be negative */
  459                 return (EINVAL);
  460         td = uio->uio_td;
  461 
  462         mtx_lock(&nmp->nm_mtx);
  463         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  464             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  465                 mtx_unlock(&nmp->nm_mtx);
  466                 (void)ncl_fsinfo(nmp, vp, cred, td);
  467                 mtx_lock(&nmp->nm_mtx);
  468         }
  469         if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
  470                 (void) newnfs_iosize(nmp);
  471         mtx_unlock(&nmp->nm_mtx);               
  472 
  473         if (vp->v_type != VDIR &&
  474             (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
  475                 return (EFBIG);
  476 
  477         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
  478                 /* No caching/ no readaheads. Just read data into the user buffer */
  479                 return ncl_readrpc(vp, uio, cred);
  480 
  481         biosize = vp->v_mount->mnt_stat.f_iosize;
  482         seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
  483         
  484         error = nfs_bioread_check_cons(vp, td, cred);
  485         if (error)
  486                 return error;
  487 
  488         do {
  489             u_quad_t nsize;
  490                         
  491             mtx_lock(&np->n_mtx);
  492             nsize = np->n_size;
  493             mtx_unlock(&np->n_mtx);                 
  494 
  495             switch (vp->v_type) {
  496             case VREG:
  497                 NFSINCRGLOBAL(newnfsstats.biocache_reads);
  498                 lbn = uio->uio_offset / biosize;
  499                 on = uio->uio_offset & (biosize - 1);
  500 
  501                 /*
  502                  * Start the read ahead(s), as required.
  503                  */
  504                 if (nmp->nm_readahead > 0) {
  505                     for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
  506                         (off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
  507                         rabn = lbn + 1 + nra;
  508                         if (incore(&vp->v_bufobj, rabn) == NULL) {
  509                             rabp = nfs_getcacheblk(vp, rabn, biosize, td);
  510                             if (!rabp) {
  511                                 error = newnfs_sigintr(nmp, td);
  512                                 if (error)
  513                                     return (error);
  514                                 else
  515                                     break;
  516                             }
  517                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  518                                 rabp->b_flags |= B_ASYNC;
  519                                 rabp->b_iocmd = BIO_READ;
  520                                 vfs_busy_pages(rabp, 0);
  521                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  522                                     rabp->b_flags |= B_INVAL;
  523                                     rabp->b_ioflags |= BIO_ERROR;
  524                                     vfs_unbusy_pages(rabp);
  525                                     brelse(rabp);
  526                                     break;
  527                                 }
  528                             } else {
  529                                 brelse(rabp);
  530                             }
  531                         }
  532                     }
  533                 }
  534 
  535                 /* Note that bcount is *not* DEV_BSIZE aligned. */
  536                 bcount = biosize;
  537                 if ((off_t)lbn * biosize >= nsize) {
  538                         bcount = 0;
  539                 } else if ((off_t)(lbn + 1) * biosize > nsize) {
  540                         bcount = nsize - (off_t)lbn * biosize;
  541                 }
  542                 bp = nfs_getcacheblk(vp, lbn, bcount, td);
  543 
  544                 if (!bp) {
  545                         error = newnfs_sigintr(nmp, td);
  546                         return (error ? error : EINTR);
  547                 }
  548 
  549                 /*
  550                  * If B_CACHE is not set, we must issue the read.  If this
  551                  * fails, we return an error.
  552                  */
  553 
  554                 if ((bp->b_flags & B_CACHE) == 0) {
  555                     bp->b_iocmd = BIO_READ;
  556                     vfs_busy_pages(bp, 0);
  557                     error = ncl_doio(vp, bp, cred, td, 0);
  558                     if (error) {
  559                         brelse(bp);
  560                         return (error);
  561                     }
  562                 }
  563 
  564                 /*
  565                  * on is the offset into the current bp.  Figure out how many
  566                  * bytes we can copy out of the bp.  Note that bcount is
  567                  * NOT DEV_BSIZE aligned.
  568                  *
  569                  * Then figure out how many bytes we can copy into the uio.
  570                  */
  571 
  572                 n = 0;
  573                 if (on < bcount)
  574                         n = min((unsigned)(bcount - on), uio->uio_resid);
  575                 break;
  576             case VLNK:
  577                 NFSINCRGLOBAL(newnfsstats.biocache_readlinks);
  578                 bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
  579                 if (!bp) {
  580                         error = newnfs_sigintr(nmp, td);
  581                         return (error ? error : EINTR);
  582                 }
  583                 if ((bp->b_flags & B_CACHE) == 0) {
  584                     bp->b_iocmd = BIO_READ;
  585                     vfs_busy_pages(bp, 0);
  586                     error = ncl_doio(vp, bp, cred, td, 0);
  587                     if (error) {
  588                         bp->b_ioflags |= BIO_ERROR;
  589                         brelse(bp);
  590                         return (error);
  591                     }
  592                 }
  593                 n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
  594                 on = 0;
  595                 break;
  596             case VDIR:
  597                 NFSINCRGLOBAL(newnfsstats.biocache_readdirs);
  598                 if (np->n_direofoffset
  599                     && uio->uio_offset >= np->n_direofoffset) {
  600                     return (0);
  601                 }
  602                 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
  603                 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
  604                 bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
  605                 if (!bp) {
  606                     error = newnfs_sigintr(nmp, td);
  607                     return (error ? error : EINTR);
  608                 }
  609                 if ((bp->b_flags & B_CACHE) == 0) {
  610                     bp->b_iocmd = BIO_READ;
  611                     vfs_busy_pages(bp, 0);
  612                     error = ncl_doio(vp, bp, cred, td, 0);
  613                     if (error) {
  614                             brelse(bp);
  615                     }
  616                     while (error == NFSERR_BAD_COOKIE) {
  617                         ncl_invaldir(vp);
  618                         error = ncl_vinvalbuf(vp, 0, td, 1);
  619                         /*
  620                          * Yuck! The directory has been modified on the
  621                          * server. The only way to get the block is by
  622                          * reading from the beginning to get all the
  623                          * offset cookies.
  624                          *
  625                          * Leave the last bp intact unless there is an error.
  626                          * Loop back up to the while if the error is another
  627                          * NFSERR_BAD_COOKIE (double yuch!).
  628                          */
  629                         for (i = 0; i <= lbn && !error; i++) {
  630                             if (np->n_direofoffset
  631                                 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
  632                                     return (0);
  633                             bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
  634                             if (!bp) {
  635                                 error = newnfs_sigintr(nmp, td);
  636                                 return (error ? error : EINTR);
  637                             }
  638                             if ((bp->b_flags & B_CACHE) == 0) {
  639                                     bp->b_iocmd = BIO_READ;
  640                                     vfs_busy_pages(bp, 0);
  641                                     error = ncl_doio(vp, bp, cred, td, 0);
  642                                     /*
  643                                      * no error + B_INVAL == directory EOF,
  644                                      * use the block.
  645                                      */
  646                                     if (error == 0 && (bp->b_flags & B_INVAL))
  647                                             break;
  648                             }
  649                             /*
  650                              * An error will throw away the block and the
  651                              * for loop will break out.  If no error and this
  652                              * is not the block we want, we throw away the
  653                              * block and go for the next one via the for loop.
  654                              */
  655                             if (error || i < lbn)
  656                                     brelse(bp);
  657                         }
  658                     }
  659                     /*
  660                      * The above while is repeated if we hit another cookie
  661                      * error.  If we hit an error and it wasn't a cookie error,
  662                      * we give up.
  663                      */
  664                     if (error)
  665                             return (error);
  666                 }
  667 
  668                 /*
  669                  * If not eof and read aheads are enabled, start one.
  670                  * (You need the current block first, so that you have the
  671                  *  directory offset cookie of the next block.)
  672                  */
  673                 if (nmp->nm_readahead > 0 &&
  674                     (bp->b_flags & B_INVAL) == 0 &&
  675                     (np->n_direofoffset == 0 ||
  676                     (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
  677                     incore(&vp->v_bufobj, lbn + 1) == NULL) {
  678                         rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
  679                         if (rabp) {
  680                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  681                                 rabp->b_flags |= B_ASYNC;
  682                                 rabp->b_iocmd = BIO_READ;
  683                                 vfs_busy_pages(rabp, 0);
  684                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  685                                     rabp->b_flags |= B_INVAL;
  686                                     rabp->b_ioflags |= BIO_ERROR;
  687                                     vfs_unbusy_pages(rabp);
  688                                     brelse(rabp);
  689                                 }
  690                             } else {
  691                                 brelse(rabp);
  692                             }
  693                         }
  694                 }
  695                 /*
  696                  * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
  697                  * chopped for the EOF condition, we cannot tell how large
  698                  * NFS directories are going to be until we hit EOF.  So
  699                  * an NFS directory buffer is *not* chopped to its EOF.  Now,
  700                  * it just so happens that b_resid will effectively chop it
  701                  * to EOF.  *BUT* this information is lost if the buffer goes
  702                  * away and is reconstituted into a B_CACHE state ( due to
  703                  * being VMIO ) later.  So we keep track of the directory eof
  704                  * in np->n_direofoffset and chop it off as an extra step
  705                  * right here.
  706                  */
  707                 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
  708                 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
  709                         n = np->n_direofoffset - uio->uio_offset;
  710                 break;
  711             default:
  712                 ncl_printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
  713                 bp = NULL;
  714                 break;
  715             };
  716 
  717             if (n > 0) {
  718                     error = uiomove(bp->b_data + on, (int)n, uio);
  719             }
  720             if (vp->v_type == VLNK)
  721                 n = 0;
  722             if (bp != NULL)
  723                 brelse(bp);
  724         } while (error == 0 && uio->uio_resid > 0 && n > 0);
  725         return (error);
  726 }
  727 
  728 /*
  729  * The NFS write path cannot handle iovecs with len > 1. So we need to 
  730  * break up iovecs accordingly (restricting them to wsize).
  731  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf). 
  732  * For the ASYNC case, 2 copies are needed. The first a copy from the 
  733  * user buffer to a staging buffer and then a second copy from the staging
  734  * buffer to mbufs. This can be optimized by copying from the user buffer
  735  * directly into mbufs and passing the chain down, but that requires a 
  736  * fair amount of re-working of the relevant codepaths (and can be done
  737  * later).
  738  */
  739 static int
  740 nfs_directio_write(vp, uiop, cred, ioflag)
  741         struct vnode *vp;
  742         struct uio *uiop;
  743         struct ucred *cred;
  744         int ioflag;
  745 {
  746         int error;
  747         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  748         struct thread *td = uiop->uio_td;
  749         int size;
  750         int wsize;
  751         
  752         mtx_lock(&nmp->nm_mtx);
  753         wsize = nmp->nm_wsize;
  754         mtx_unlock(&nmp->nm_mtx);
  755         if (ioflag & IO_SYNC) {
  756                 int iomode, must_commit;
  757                 struct uio uio;
  758                 struct iovec iov;
  759 do_sync:
  760                 while (uiop->uio_resid > 0) {
  761                         size = min(uiop->uio_resid, wsize);
  762                         size = min(uiop->uio_iov->iov_len, size);
  763                         iov.iov_base = uiop->uio_iov->iov_base;
  764                         iov.iov_len = size;
  765                         uio.uio_iov = &iov;
  766                         uio.uio_iovcnt = 1;
  767                         uio.uio_offset = uiop->uio_offset;
  768                         uio.uio_resid = size;
  769                         uio.uio_segflg = UIO_USERSPACE;
  770                         uio.uio_rw = UIO_WRITE;
  771                         uio.uio_td = td;
  772                         iomode = NFSWRITE_FILESYNC;
  773                         error = ncl_writerpc(vp, &uio, cred, &iomode,
  774                             &must_commit, 0);
  775                         KASSERT((must_commit == 0), 
  776                                 ("ncl_directio_write: Did not commit write"));
  777                         if (error)
  778                                 return (error);
  779                         uiop->uio_offset += size;
  780                         uiop->uio_resid -= size;
  781                         if (uiop->uio_iov->iov_len <= size) {
  782                                 uiop->uio_iovcnt--;
  783                                 uiop->uio_iov++;
  784                         } else {
  785                                 uiop->uio_iov->iov_base = 
  786                                         (char *)uiop->uio_iov->iov_base + size;
  787                                 uiop->uio_iov->iov_len -= size;
  788                         }
  789                 }
  790         } else {
  791                 struct uio *t_uio;
  792                 struct iovec *t_iov;
  793                 struct buf *bp;
  794                 
  795                 /*
  796                  * Break up the write into blocksize chunks and hand these
  797                  * over to nfsiod's for write back.
  798                  * Unfortunately, this incurs a copy of the data. Since 
  799                  * the user could modify the buffer before the write is 
  800                  * initiated.
  801                  * 
  802                  * The obvious optimization here is that one of the 2 copies
  803                  * in the async write path can be eliminated by copying the
  804                  * data here directly into mbufs and passing the mbuf chain
  805                  * down. But that will require a fair amount of re-working
  806                  * of the code and can be done if there's enough interest
  807                  * in NFS directio access.
  808                  */
  809                 while (uiop->uio_resid > 0) {
  810                         size = min(uiop->uio_resid, wsize);
  811                         size = min(uiop->uio_iov->iov_len, size);
  812                         bp = getpbuf(&ncl_pbuf_freecnt);
  813                         t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
  814                         t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
  815                         t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
  816                         t_iov->iov_len = size;
  817                         t_uio->uio_iov = t_iov;
  818                         t_uio->uio_iovcnt = 1;
  819                         t_uio->uio_offset = uiop->uio_offset;
  820                         t_uio->uio_resid = size;
  821                         t_uio->uio_segflg = UIO_SYSSPACE;
  822                         t_uio->uio_rw = UIO_WRITE;
  823                         t_uio->uio_td = td;
  824                         bcopy(uiop->uio_iov->iov_base, t_iov->iov_base, size);
  825                         bp->b_flags |= B_DIRECT;
  826                         bp->b_iocmd = BIO_WRITE;
  827                         if (cred != NOCRED) {
  828                                 crhold(cred);
  829                                 bp->b_wcred = cred;
  830                         } else 
  831                                 bp->b_wcred = NOCRED;                   
  832                         bp->b_caller1 = (void *)t_uio;
  833                         bp->b_vp = vp;
  834                         error = ncl_asyncio(nmp, bp, NOCRED, td);
  835                         if (error) {
  836                                 free(t_iov->iov_base, M_NFSDIRECTIO);
  837                                 free(t_iov, M_NFSDIRECTIO);
  838                                 free(t_uio, M_NFSDIRECTIO);
  839                                 bp->b_vp = NULL;
  840                                 relpbuf(bp, &ncl_pbuf_freecnt);
  841                                 if (error == EINTR)
  842                                         return (error);
  843                                 goto do_sync;
  844                         }
  845                         uiop->uio_offset += size;
  846                         uiop->uio_resid -= size;
  847                         if (uiop->uio_iov->iov_len <= size) {
  848                                 uiop->uio_iovcnt--;
  849                                 uiop->uio_iov++;
  850                         } else {
  851                                 uiop->uio_iov->iov_base = 
  852                                         (char *)uiop->uio_iov->iov_base + size;
  853                                 uiop->uio_iov->iov_len -= size;
  854                         }
  855                 }
  856         }
  857         return (0);
  858 }
  859 
  860 /*
  861  * Vnode op for write using bio
  862  */
  863 int
  864 ncl_write(struct vop_write_args *ap)
  865 {
  866         int biosize;
  867         struct uio *uio = ap->a_uio;
  868         struct thread *td = uio->uio_td;
  869         struct vnode *vp = ap->a_vp;
  870         struct nfsnode *np = VTONFS(vp);
  871         struct ucred *cred = ap->a_cred;
  872         int ioflag = ap->a_ioflag;
  873         struct buf *bp;
  874         struct vattr vattr;
  875         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  876         daddr_t lbn;
  877         int bcount;
  878         int n, on, error = 0;
  879         struct proc *p = td?td->td_proc:NULL;
  880 
  881 #ifdef DIAGNOSTIC
  882         if (uio->uio_rw != UIO_WRITE)
  883                 panic("ncl_write mode");
  884         if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
  885                 panic("ncl_write proc");
  886 #endif
  887         if (vp->v_type != VREG)
  888                 return (EIO);
  889         mtx_lock(&np->n_mtx);
  890         if (np->n_flag & NWRITEERR) {
  891                 np->n_flag &= ~NWRITEERR;
  892                 mtx_unlock(&np->n_mtx);
  893                 return (np->n_error);
  894         } else
  895                 mtx_unlock(&np->n_mtx);
  896         mtx_lock(&nmp->nm_mtx);
  897         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  898             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  899                 mtx_unlock(&nmp->nm_mtx);
  900                 (void)ncl_fsinfo(nmp, vp, cred, td);
  901                 mtx_lock(&nmp->nm_mtx);
  902         }
  903         if (nmp->nm_wsize == 0)
  904                 (void) newnfs_iosize(nmp);
  905         mtx_unlock(&nmp->nm_mtx);
  906 
  907         /*
  908          * Synchronously flush pending buffers if we are in synchronous
  909          * mode or if we are appending.
  910          */
  911         if (ioflag & (IO_APPEND | IO_SYNC)) {
  912                 mtx_lock(&np->n_mtx);
  913                 if (np->n_flag & NMODIFIED) {
  914                         mtx_unlock(&np->n_mtx);
  915 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
  916                         /*
  917                          * Require non-blocking, synchronous writes to
  918                          * dirty files to inform the program it needs
  919                          * to fsync(2) explicitly.
  920                          */
  921                         if (ioflag & IO_NDELAY)
  922                                 return (EAGAIN);
  923 #endif
  924 flush_and_restart:
  925                         np->n_attrstamp = 0;
  926                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  927                         if (error)
  928                                 return (error);
  929                 } else
  930                         mtx_unlock(&np->n_mtx);
  931         }
  932 
  933         /*
  934          * If IO_APPEND then load uio_offset.  We restart here if we cannot
  935          * get the append lock.
  936          */
  937         if (ioflag & IO_APPEND) {
  938                 np->n_attrstamp = 0;
  939                 error = VOP_GETATTR(vp, &vattr, cred);
  940                 if (error)
  941                         return (error);
  942                 mtx_lock(&np->n_mtx);
  943                 uio->uio_offset = np->n_size;
  944                 mtx_unlock(&np->n_mtx);
  945         }
  946 
  947         if (uio->uio_offset < 0)
  948                 return (EINVAL);
  949         if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
  950                 return (EFBIG);
  951         if (uio->uio_resid == 0)
  952                 return (0);
  953 
  954         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
  955                 return nfs_directio_write(vp, uio, cred, ioflag);
  956 
  957         /*
  958          * Maybe this should be above the vnode op call, but so long as
  959          * file servers have no limits, i don't think it matters
  960          */
  961         if (p != NULL) {
  962                 PROC_LOCK(p);
  963                 if (uio->uio_offset + uio->uio_resid >
  964                     lim_cur(p, RLIMIT_FSIZE)) {
  965                         psignal(p, SIGXFSZ);
  966                         PROC_UNLOCK(p);
  967                         return (EFBIG);
  968                 }
  969                 PROC_UNLOCK(p);
  970         }
  971 
  972         biosize = vp->v_mount->mnt_stat.f_iosize;
  973         /*
  974          * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
  975          * would exceed the local maximum per-file write commit size when
  976          * combined with those, we must decide whether to flush,
  977          * go synchronous, or return error.  We don't bother checking
  978          * IO_UNIT -- we just make all writes atomic anyway, as there's
  979          * no point optimizing for something that really won't ever happen.
  980          */
  981         if (!(ioflag & IO_SYNC)) {
  982                 int nflag;
  983 
  984                 mtx_lock(&np->n_mtx);
  985                 nflag = np->n_flag;
  986                 mtx_unlock(&np->n_mtx);         
  987                 int needrestart = 0;
  988                 if (nmp->nm_wcommitsize < uio->uio_resid) {
  989                         /*
  990                          * If this request could not possibly be completed
  991                          * without exceeding the maximum outstanding write
  992                          * commit size, see if we can convert it into a
  993                          * synchronous write operation.
  994                          */
  995                         if (ioflag & IO_NDELAY)
  996                                 return (EAGAIN);
  997                         ioflag |= IO_SYNC;
  998                         if (nflag & NMODIFIED)
  999                                 needrestart = 1;
 1000                 } else if (nflag & NMODIFIED) {
 1001                         int wouldcommit = 0;
 1002                         BO_LOCK(&vp->v_bufobj);
 1003                         if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
 1004                                 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
 1005                                     b_bobufs) {
 1006                                         if (bp->b_flags & B_NEEDCOMMIT)
 1007                                                 wouldcommit += bp->b_bcount;
 1008                                 }
 1009                         }
 1010                         BO_UNLOCK(&vp->v_bufobj);
 1011                         /*
 1012                          * Since we're not operating synchronously and
 1013                          * bypassing the buffer cache, we are in a commit
 1014                          * and holding all of these buffers whether
 1015                          * transmitted or not.  If not limited, this
 1016                          * will lead to the buffer cache deadlocking,
 1017                          * as no one else can flush our uncommitted buffers.
 1018                          */
 1019                         wouldcommit += uio->uio_resid;
 1020                         /*
 1021                          * If we would initially exceed the maximum
 1022                          * outstanding write commit size, flush and restart.
 1023                          */
 1024                         if (wouldcommit > nmp->nm_wcommitsize)
 1025                                 needrestart = 1;
 1026                 }
 1027                 if (needrestart)
 1028                         goto flush_and_restart;
 1029         }
 1030 
 1031         do {
 1032                 NFSINCRGLOBAL(newnfsstats.biocache_writes);
 1033                 lbn = uio->uio_offset / biosize;
 1034                 on = uio->uio_offset & (biosize-1);
 1035                 n = min((unsigned)(biosize - on), uio->uio_resid);
 1036 again:
 1037                 /*
 1038                  * Handle direct append and file extension cases, calculate
 1039                  * unaligned buffer size.
 1040                  */
 1041                 mtx_lock(&np->n_mtx);
 1042                 if (uio->uio_offset == np->n_size && n) {
 1043                         mtx_unlock(&np->n_mtx);
 1044                         /*
 1045                          * Get the buffer (in its pre-append state to maintain
 1046                          * B_CACHE if it was previously set).  Resize the
 1047                          * nfsnode after we have locked the buffer to prevent
 1048                          * readers from reading garbage.
 1049                          */
 1050                         bcount = on;
 1051                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1052 
 1053                         if (bp != NULL) {
 1054                                 long save;
 1055 
 1056                                 mtx_lock(&np->n_mtx);
 1057                                 np->n_size = uio->uio_offset + n;
 1058                                 np->n_flag |= NMODIFIED;
 1059                                 vnode_pager_setsize(vp, np->n_size);
 1060                                 mtx_unlock(&np->n_mtx);
 1061 
 1062                                 save = bp->b_flags & B_CACHE;
 1063                                 bcount += n;
 1064                                 allocbuf(bp, bcount);
 1065                                 bp->b_flags |= save;
 1066                         }
 1067                 } else {
 1068                         /*
 1069                          * Obtain the locked cache block first, and then
 1070                          * adjust the file's size as appropriate.
 1071                          */
 1072                         bcount = on + n;
 1073                         if ((off_t)lbn * biosize + bcount < np->n_size) {
 1074                                 if ((off_t)(lbn + 1) * biosize < np->n_size)
 1075                                         bcount = biosize;
 1076                                 else
 1077                                         bcount = np->n_size - (off_t)lbn * biosize;
 1078                         }
 1079                         mtx_unlock(&np->n_mtx);
 1080                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1081                         mtx_lock(&np->n_mtx);
 1082                         if (uio->uio_offset + n > np->n_size) {
 1083                                 np->n_size = uio->uio_offset + n;
 1084                                 np->n_flag |= NMODIFIED;
 1085                                 vnode_pager_setsize(vp, np->n_size);
 1086                         }
 1087                         mtx_unlock(&np->n_mtx);
 1088                 }
 1089 
 1090                 if (!bp) {
 1091                         error = newnfs_sigintr(nmp, td);
 1092                         if (!error)
 1093                                 error = EINTR;
 1094                         break;
 1095                 }
 1096 
 1097                 /*
 1098                  * Issue a READ if B_CACHE is not set.  In special-append
 1099                  * mode, B_CACHE is based on the buffer prior to the write
 1100                  * op and is typically set, avoiding the read.  If a read
 1101                  * is required in special append mode, the server will
 1102                  * probably send us a short-read since we extended the file
 1103                  * on our end, resulting in b_resid == 0 and, thusly,
 1104                  * B_CACHE getting set.
 1105                  *
 1106                  * We can also avoid issuing the read if the write covers
 1107                  * the entire buffer.  We have to make sure the buffer state
 1108                  * is reasonable in this case since we will not be initiating
 1109                  * I/O.  See the comments in kern/vfs_bio.c's getblk() for
 1110                  * more information.
 1111                  *
 1112                  * B_CACHE may also be set due to the buffer being cached
 1113                  * normally.
 1114                  */
 1115 
 1116                 if (on == 0 && n == bcount) {
 1117                         bp->b_flags |= B_CACHE;
 1118                         bp->b_flags &= ~B_INVAL;
 1119                         bp->b_ioflags &= ~BIO_ERROR;
 1120                 }
 1121 
 1122                 if ((bp->b_flags & B_CACHE) == 0) {
 1123                         bp->b_iocmd = BIO_READ;
 1124                         vfs_busy_pages(bp, 0);
 1125                         error = ncl_doio(vp, bp, cred, td, 0);
 1126                         if (error) {
 1127                                 brelse(bp);
 1128                                 break;
 1129                         }
 1130                 }
 1131                 if (bp->b_wcred == NOCRED)
 1132                         bp->b_wcred = crhold(cred);
 1133                 mtx_lock(&np->n_mtx);
 1134                 np->n_flag |= NMODIFIED;
 1135                 mtx_unlock(&np->n_mtx);
 1136 
 1137                 /*
 1138                  * If dirtyend exceeds file size, chop it down.  This should
 1139                  * not normally occur but there is an append race where it
 1140                  * might occur XXX, so we log it.
 1141                  *
 1142                  * If the chopping creates a reverse-indexed or degenerate
 1143                  * situation with dirtyoff/end, we 0 both of them.
 1144                  */
 1145 
 1146                 if (bp->b_dirtyend > bcount) {
 1147                         ncl_printf("NFS append race @%lx:%d\n",
 1148                             (long)bp->b_blkno * DEV_BSIZE,
 1149                             bp->b_dirtyend - bcount);
 1150                         bp->b_dirtyend = bcount;
 1151                 }
 1152 
 1153                 if (bp->b_dirtyoff >= bp->b_dirtyend)
 1154                         bp->b_dirtyoff = bp->b_dirtyend = 0;
 1155 
 1156                 /*
 1157                  * If the new write will leave a contiguous dirty
 1158                  * area, just update the b_dirtyoff and b_dirtyend,
 1159                  * otherwise force a write rpc of the old dirty area.
 1160                  *
 1161                  * While it is possible to merge discontiguous writes due to
 1162                  * our having a B_CACHE buffer ( and thus valid read data
 1163                  * for the hole), we don't because it could lead to
 1164                  * significant cache coherency problems with multiple clients,
 1165                  * especially if locking is implemented later on.
 1166                  *
 1167                  * as an optimization we could theoretically maintain
 1168                  * a linked list of discontinuous areas, but we would still
 1169                  * have to commit them separately so there isn't much
 1170                  * advantage to it except perhaps a bit of asynchronization.
 1171                  */
 1172 
 1173                 if (bp->b_dirtyend > 0 &&
 1174                     (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
 1175                         if (bwrite(bp) == EINTR) {
 1176                                 error = EINTR;
 1177                                 break;
 1178                         }
 1179                         goto again;
 1180                 }
 1181 
 1182                 error = uiomove((char *)bp->b_data + on, n, uio);
 1183 
 1184                 /*
 1185                  * Since this block is being modified, it must be written
 1186                  * again and not just committed.  Since write clustering does
 1187                  * not work for the stage 1 data write, only the stage 2
 1188                  * commit rpc, we have to clear B_CLUSTEROK as well.
 1189                  */
 1190                 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1191 
 1192                 if (error) {
 1193                         bp->b_ioflags |= BIO_ERROR;
 1194                         brelse(bp);
 1195                         break;
 1196                 }
 1197 
 1198                 /*
 1199                  * Only update dirtyoff/dirtyend if not a degenerate
 1200                  * condition.
 1201                  */
 1202                 if (n) {
 1203                         if (bp->b_dirtyend > 0) {
 1204                                 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
 1205                                 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
 1206                         } else {
 1207                                 bp->b_dirtyoff = on;
 1208                                 bp->b_dirtyend = on + n;
 1209                         }
 1210                         vfs_bio_set_valid(bp, on, n);
 1211                 }
 1212 
 1213                 /*
 1214                  * If IO_SYNC do bwrite().
 1215                  *
 1216                  * IO_INVAL appears to be unused.  The idea appears to be
 1217                  * to turn off caching in this case.  Very odd.  XXX
 1218                  */
 1219                 if ((ioflag & IO_SYNC)) {
 1220                         if (ioflag & IO_INVAL)
 1221                                 bp->b_flags |= B_NOCACHE;
 1222                         error = bwrite(bp);
 1223                         if (error)
 1224                                 break;
 1225                 } else if ((n + on) == biosize) {
 1226                         bp->b_flags |= B_ASYNC;
 1227                         (void) ncl_writebp(bp, 0, NULL);
 1228                 } else {
 1229                         bdwrite(bp);
 1230                 }
 1231         } while (uio->uio_resid > 0 && n > 0);
 1232 
 1233         return (error);
 1234 }
 1235 
 1236 /*
 1237  * Get an nfs cache block.
 1238  *
 1239  * Allocate a new one if the block isn't currently in the cache
 1240  * and return the block marked busy. If the calling process is
 1241  * interrupted by a signal for an interruptible mount point, return
 1242  * NULL.
 1243  *
 1244  * The caller must carefully deal with the possible B_INVAL state of
 1245  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
 1246  * indirectly), so synchronous reads can be issued without worrying about
 1247  * the B_INVAL state.  We have to be a little more careful when dealing
 1248  * with writes (see comments in nfs_write()) when extending a file past
 1249  * its EOF.
 1250  */
 1251 static struct buf *
 1252 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
 1253 {
 1254         struct buf *bp;
 1255         struct mount *mp;
 1256         struct nfsmount *nmp;
 1257 
 1258         mp = vp->v_mount;
 1259         nmp = VFSTONFS(mp);
 1260 
 1261         if (nmp->nm_flag & NFSMNT_INT) {
 1262                 sigset_t oldset;
 1263 
 1264                 newnfs_set_sigmask(td, &oldset);
 1265                 bp = getblk(vp, bn, size, NFS_PCATCH, 0, 0);
 1266                 newnfs_restore_sigmask(td, &oldset);
 1267                 while (bp == NULL) {
 1268                         if (newnfs_sigintr(nmp, td))
 1269                                 return (NULL);
 1270                         bp = getblk(vp, bn, size, 0, 2 * hz, 0);
 1271                 }
 1272         } else {
 1273                 bp = getblk(vp, bn, size, 0, 0, 0);
 1274         }
 1275 
 1276         if (vp->v_type == VREG) {
 1277                 int biosize;
 1278 
 1279                 biosize = mp->mnt_stat.f_iosize;
 1280                 bp->b_blkno = bn * (biosize / DEV_BSIZE);
 1281         }
 1282         return (bp);
 1283 }
 1284 
 1285 /*
 1286  * Flush and invalidate all dirty buffers. If another process is already
 1287  * doing the flush, just wait for completion.
 1288  */
 1289 int
 1290 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
 1291 {
 1292         struct nfsnode *np = VTONFS(vp);
 1293         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 1294         int error = 0, slpflag, slptimeo;
 1295         int old_lock = 0;
 1296 
 1297         ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
 1298 
 1299         if ((nmp->nm_flag & NFSMNT_INT) == 0)
 1300                 intrflg = 0;
 1301         if ((nmp->nm_mountp->mnt_kern_flag & MNTK_UNMOUNTF))
 1302                 intrflg = 1;
 1303         if (intrflg) {
 1304                 slpflag = NFS_PCATCH;
 1305                 slptimeo = 2 * hz;
 1306         } else {
 1307                 slpflag = 0;
 1308                 slptimeo = 0;
 1309         }
 1310 
 1311         old_lock = ncl_upgrade_vnlock(vp);
 1312         if (vp->v_iflag & VI_DOOMED) {
 1313                 /*
 1314                  * Since vgonel() uses the generic vinvalbuf() to flush
 1315                  * dirty buffers and it does not call this function, it
 1316                  * is safe to just return OK when VI_DOOMED is set.
 1317                  */
 1318                 ncl_downgrade_vnlock(vp, old_lock);
 1319                 return (0);
 1320         }
 1321 
 1322         /*
 1323          * Now, flush as required.
 1324          */
 1325         if ((flags & V_SAVE) && (vp->v_bufobj.bo_object != NULL)) {
 1326                 VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
 1327                 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
 1328                 VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
 1329                 /*
 1330                  * If the page clean was interrupted, fail the invalidation.
 1331                  * Not doing so, we run the risk of losing dirty pages in the 
 1332                  * vinvalbuf() call below.
 1333                  */
 1334                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1335                         goto out;
 1336         }
 1337 
 1338         error = vinvalbuf(vp, flags, slpflag, 0);
 1339         while (error) {
 1340                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1341                         goto out;
 1342                 error = vinvalbuf(vp, flags, 0, slptimeo);
 1343         }
 1344         mtx_lock(&np->n_mtx);
 1345         if (np->n_directio_asyncwr == 0)
 1346                 np->n_flag &= ~NMODIFIED;
 1347         mtx_unlock(&np->n_mtx);
 1348 out:
 1349         ncl_downgrade_vnlock(vp, old_lock);
 1350         return error;
 1351 }
 1352 
 1353 /*
 1354  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
 1355  * This is mainly to avoid queueing async I/O requests when the nfsiods
 1356  * are all hung on a dead server.
 1357  *
 1358  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
 1359  * is eventually dequeued by the async daemon, ncl_doio() *will*.
 1360  */
 1361 int
 1362 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
 1363 {
 1364         int iod;
 1365         int gotiod;
 1366         int slpflag = 0;
 1367         int slptimeo = 0;
 1368         int error, error2;
 1369 
 1370         /*
 1371          * Unless iothreadcnt is set > 0, don't bother with async I/O
 1372          * threads. For LAN environments, they don't buy any significant
 1373          * performance improvement that you can't get with large block
 1374          * sizes.
 1375          */
 1376         if (nmp->nm_readahead == 0)
 1377                 return (EPERM);
 1378 
 1379         /*
 1380          * Commits are usually short and sweet so lets save some cpu and
 1381          * leave the async daemons for more important rpc's (such as reads
 1382          * and writes).
 1383          */
 1384         mtx_lock(&ncl_iod_mutex);
 1385         if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
 1386             (nmp->nm_bufqiods > ncl_numasync / 2)) {
 1387                 mtx_unlock(&ncl_iod_mutex);
 1388                 return(EIO);
 1389         }
 1390 again:
 1391         if (nmp->nm_flag & NFSMNT_INT)
 1392                 slpflag = NFS_PCATCH;
 1393         gotiod = FALSE;
 1394 
 1395         /*
 1396          * Find a free iod to process this request.
 1397          */
 1398         for (iod = 0; iod < ncl_numasync; iod++)
 1399                 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
 1400                         gotiod = TRUE;
 1401                         break;
 1402                 }
 1403 
 1404         /*
 1405          * Try to create one if none are free.
 1406          */
 1407         if (!gotiod) {
 1408                 iod = ncl_nfsiodnew(1);
 1409                 if (iod != -1)
 1410                         gotiod = TRUE;
 1411         }
 1412 
 1413         if (gotiod) {
 1414                 /*
 1415                  * Found one, so wake it up and tell it which
 1416                  * mount to process.
 1417                  */
 1418                 NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
 1419                     iod, nmp));
 1420                 ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
 1421                 ncl_iodmount[iod] = nmp;
 1422                 nmp->nm_bufqiods++;
 1423                 wakeup(&ncl_iodwant[iod]);
 1424         }
 1425 
 1426         /*
 1427          * If none are free, we may already have an iod working on this mount
 1428          * point.  If so, it will process our request.
 1429          */
 1430         if (!gotiod) {
 1431                 if (nmp->nm_bufqiods > 0) {
 1432                         NFS_DPF(ASYNCIO,
 1433                                 ("ncl_asyncio: %d iods are already processing mount %p\n",
 1434                                  nmp->nm_bufqiods, nmp));
 1435                         gotiod = TRUE;
 1436                 }
 1437         }
 1438 
 1439         /*
 1440          * If we have an iod which can process the request, then queue
 1441          * the buffer.
 1442          */
 1443         if (gotiod) {
 1444                 /*
 1445                  * Ensure that the queue never grows too large.  We still want
 1446                  * to asynchronize so we block rather then return EIO.
 1447                  */
 1448                 while (nmp->nm_bufqlen >= 2*ncl_numasync) {
 1449                         NFS_DPF(ASYNCIO,
 1450                                 ("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
 1451                         nmp->nm_bufqwant = TRUE;
 1452                         error = newnfs_msleep(td, &nmp->nm_bufq, 
 1453                             &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
 1454                            slptimeo);
 1455                         if (error) {
 1456                                 error2 = newnfs_sigintr(nmp, td);
 1457                                 if (error2) {
 1458                                         mtx_unlock(&ncl_iod_mutex);                                     
 1459                                         return (error2);
 1460                                 }
 1461                                 if (slpflag == NFS_PCATCH) {
 1462                                         slpflag = 0;
 1463                                         slptimeo = 2 * hz;
 1464                                 }
 1465                         }
 1466                         /*
 1467                          * We might have lost our iod while sleeping,
 1468                          * so check and loop if nescessary.
 1469                          */
 1470                         if (nmp->nm_bufqiods == 0) {
 1471                                 NFS_DPF(ASYNCIO,
 1472                                         ("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
 1473                                 goto again;
 1474                         }
 1475                 }
 1476 
 1477                 /* We might have lost our nfsiod */
 1478                 if (nmp->nm_bufqiods == 0) {
 1479                         NFS_DPF(ASYNCIO,
 1480                                 ("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
 1481                         goto again;
 1482                 }
 1483 
 1484                 if (bp->b_iocmd == BIO_READ) {
 1485                         if (bp->b_rcred == NOCRED && cred != NOCRED)
 1486                                 bp->b_rcred = crhold(cred);
 1487                 } else {
 1488                         if (bp->b_wcred == NOCRED && cred != NOCRED)
 1489                                 bp->b_wcred = crhold(cred);
 1490                 }
 1491 
 1492                 if (bp->b_flags & B_REMFREE)
 1493                         bremfreef(bp);
 1494                 BUF_KERNPROC(bp);
 1495                 TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
 1496                 nmp->nm_bufqlen++;
 1497                 if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1498                         mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);                   
 1499                         VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
 1500                         VTONFS(bp->b_vp)->n_directio_asyncwr++;
 1501                         mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
 1502                 }
 1503                 mtx_unlock(&ncl_iod_mutex);
 1504                 return (0);
 1505         }
 1506 
 1507         mtx_unlock(&ncl_iod_mutex);
 1508 
 1509         /*
 1510          * All the iods are busy on other mounts, so return EIO to
 1511          * force the caller to process the i/o synchronously.
 1512          */
 1513         NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
 1514         return (EIO);
 1515 }
 1516 
 1517 void
 1518 ncl_doio_directwrite(struct buf *bp)
 1519 {
 1520         int iomode, must_commit;
 1521         struct uio *uiop = (struct uio *)bp->b_caller1;
 1522         char *iov_base = uiop->uio_iov->iov_base;
 1523         
 1524         iomode = NFSWRITE_FILESYNC;
 1525         uiop->uio_td = NULL; /* NULL since we're in nfsiod */
 1526         ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
 1527         KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
 1528         free(iov_base, M_NFSDIRECTIO);
 1529         free(uiop->uio_iov, M_NFSDIRECTIO);
 1530         free(uiop, M_NFSDIRECTIO);
 1531         if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1532                 struct nfsnode *np = VTONFS(bp->b_vp);
 1533                 mtx_lock(&np->n_mtx);
 1534                 np->n_directio_asyncwr--;
 1535                 if (np->n_directio_asyncwr == 0) {
 1536                         np->n_flag &= ~NMODIFIED;
 1537                         if ((np->n_flag & NFSYNCWAIT)) {
 1538                                 np->n_flag &= ~NFSYNCWAIT;
 1539                                 wakeup((caddr_t)&np->n_directio_asyncwr);
 1540                         }
 1541                 }
 1542                 mtx_unlock(&np->n_mtx);
 1543         }
 1544         bp->b_vp = NULL;
 1545         relpbuf(bp, &ncl_pbuf_freecnt);
 1546 }
 1547 
 1548 /*
 1549  * Do an I/O operation to/from a cache block. This may be called
 1550  * synchronously or from an nfsiod.
 1551  */
 1552 int
 1553 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
 1554     int called_from_strategy)
 1555 {
 1556         struct uio *uiop;
 1557         struct nfsnode *np;
 1558         struct nfsmount *nmp;
 1559         int error = 0, iomode, must_commit = 0;
 1560         struct uio uio;
 1561         struct iovec io;
 1562         struct proc *p = td ? td->td_proc : NULL;
 1563         uint8_t iocmd;
 1564         
 1565         np = VTONFS(vp);
 1566         nmp = VFSTONFS(vp->v_mount);
 1567         uiop = &uio;
 1568         uiop->uio_iov = &io;
 1569         uiop->uio_iovcnt = 1;
 1570         uiop->uio_segflg = UIO_SYSSPACE;
 1571         uiop->uio_td = td;
 1572 
 1573         /*
 1574          * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
 1575          * do this here so we do not have to do it in all the code that
 1576          * calls us.
 1577          */
 1578         bp->b_flags &= ~B_INVAL;
 1579         bp->b_ioflags &= ~BIO_ERROR;
 1580 
 1581         KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
 1582         iocmd = bp->b_iocmd;
 1583         if (iocmd == BIO_READ) {
 1584             io.iov_len = uiop->uio_resid = bp->b_bcount;
 1585             io.iov_base = bp->b_data;
 1586             uiop->uio_rw = UIO_READ;
 1587 
 1588             switch (vp->v_type) {
 1589             case VREG:
 1590                 uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
 1591                 NFSINCRGLOBAL(newnfsstats.read_bios);
 1592                 error = ncl_readrpc(vp, uiop, cr);
 1593 
 1594                 if (!error) {
 1595                     if (uiop->uio_resid) {
 1596                         /*
 1597                          * If we had a short read with no error, we must have
 1598                          * hit a file hole.  We should zero-fill the remainder.
 1599                          * This can also occur if the server hits the file EOF.
 1600                          *
 1601                          * Holes used to be able to occur due to pending
 1602                          * writes, but that is not possible any longer.
 1603                          */
 1604                         int nread = bp->b_bcount - uiop->uio_resid;
 1605                         int left  = uiop->uio_resid;
 1606 
 1607                         if (left > 0)
 1608                                 bzero((char *)bp->b_data + nread, left);
 1609                         uiop->uio_resid = 0;
 1610                     }
 1611                 }
 1612                 /* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
 1613                 if (p && (vp->v_vflag & VV_TEXT)) {
 1614                         mtx_lock(&np->n_mtx);
 1615                         if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
 1616                                 mtx_unlock(&np->n_mtx);
 1617                                 PROC_LOCK(p);
 1618                                 killproc(p, "text file modification");
 1619                                 PROC_UNLOCK(p);
 1620                         } else
 1621                                 mtx_unlock(&np->n_mtx);
 1622                 }
 1623                 break;
 1624             case VLNK:
 1625                 uiop->uio_offset = (off_t)0;
 1626                 NFSINCRGLOBAL(newnfsstats.readlink_bios);
 1627                 error = ncl_readlinkrpc(vp, uiop, cr);
 1628                 break;
 1629             case VDIR:
 1630                 NFSINCRGLOBAL(newnfsstats.readdir_bios);
 1631                 uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
 1632                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
 1633                         error = ncl_readdirplusrpc(vp, uiop, cr, td);
 1634                         if (error == NFSERR_NOTSUPP)
 1635                                 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
 1636                 }
 1637                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
 1638                         error = ncl_readdirrpc(vp, uiop, cr, td);
 1639                 /*
 1640                  * end-of-directory sets B_INVAL but does not generate an
 1641                  * error.
 1642                  */
 1643                 if (error == 0 && uiop->uio_resid == bp->b_bcount)
 1644                         bp->b_flags |= B_INVAL;
 1645                 break;
 1646             default:
 1647                 ncl_printf("ncl_doio:  type %x unexpected\n", vp->v_type);
 1648                 break;
 1649             };
 1650             if (error) {
 1651                 bp->b_ioflags |= BIO_ERROR;
 1652                 bp->b_error = error;
 1653             }
 1654         } else {
 1655             /*
 1656              * If we only need to commit, try to commit
 1657              */
 1658             if (bp->b_flags & B_NEEDCOMMIT) {
 1659                     int retv;
 1660                     off_t off;
 1661 
 1662                     off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
 1663                     retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
 1664                         bp->b_wcred, td);
 1665                     if (retv == 0) {
 1666                             bp->b_dirtyoff = bp->b_dirtyend = 0;
 1667                             bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1668                             bp->b_resid = 0;
 1669                             bufdone(bp);
 1670                             return (0);
 1671                     }
 1672                     if (retv == NFSERR_STALEWRITEVERF) {
 1673                             ncl_clearcommit(vp->v_mount);
 1674                     }
 1675             }
 1676 
 1677             /*
 1678              * Setup for actual write
 1679              */
 1680             mtx_lock(&np->n_mtx);
 1681             if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
 1682                 bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
 1683             mtx_unlock(&np->n_mtx);
 1684 
 1685             if (bp->b_dirtyend > bp->b_dirtyoff) {
 1686                 io.iov_len = uiop->uio_resid = bp->b_dirtyend
 1687                     - bp->b_dirtyoff;
 1688                 uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
 1689                     + bp->b_dirtyoff;
 1690                 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
 1691                 uiop->uio_rw = UIO_WRITE;
 1692                 NFSINCRGLOBAL(newnfsstats.write_bios);
 1693 
 1694                 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
 1695                     iomode = NFSWRITE_UNSTABLE;
 1696                 else
 1697                     iomode = NFSWRITE_FILESYNC;
 1698 
 1699                 error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
 1700                     called_from_strategy);
 1701 
 1702                 /*
 1703                  * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
 1704                  * to cluster the buffers needing commit.  This will allow
 1705                  * the system to submit a single commit rpc for the whole
 1706                  * cluster.  We can do this even if the buffer is not 100%
 1707                  * dirty (relative to the NFS blocksize), so we optimize the
 1708                  * append-to-file-case.
 1709                  *
 1710                  * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
 1711                  * cleared because write clustering only works for commit
 1712                  * rpc's, not for the data portion of the write).
 1713                  */
 1714 
 1715                 if (!error && iomode == NFSWRITE_UNSTABLE) {
 1716                     bp->b_flags |= B_NEEDCOMMIT;
 1717                     if (bp->b_dirtyoff == 0
 1718                         && bp->b_dirtyend == bp->b_bcount)
 1719                         bp->b_flags |= B_CLUSTEROK;
 1720                 } else {
 1721                     bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1722                 }
 1723 
 1724                 /*
 1725                  * For an interrupted write, the buffer is still valid
 1726                  * and the write hasn't been pushed to the server yet,
 1727                  * so we can't set BIO_ERROR and report the interruption
 1728                  * by setting B_EINTR. For the B_ASYNC case, B_EINTR
 1729                  * is not relevant, so the rpc attempt is essentially
 1730                  * a noop.  For the case of a V3 write rpc not being
 1731                  * committed to stable storage, the block is still
 1732                  * dirty and requires either a commit rpc or another
 1733                  * write rpc with iomode == NFSV3WRITE_FILESYNC before
 1734                  * the block is reused. This is indicated by setting
 1735                  * the B_DELWRI and B_NEEDCOMMIT flags.
 1736                  *
 1737                  * EIO is returned by ncl_writerpc() to indicate a recoverable
 1738                  * write error and is handled as above, except that
 1739                  * B_EINTR isn't set. One cause of this is a stale stateid
 1740                  * error for the RPC that indicates recovery is required,
 1741                  * when called with called_from_strategy != 0.
 1742                  *
 1743                  * If the buffer is marked B_PAGING, it does not reside on
 1744                  * the vp's paging queues so we cannot call bdirty().  The
 1745                  * bp in this case is not an NFS cache block so we should
 1746                  * be safe. XXX
 1747                  *
 1748                  * The logic below breaks up errors into recoverable and 
 1749                  * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
 1750                  * and keep the buffer around for potential write retries.
 1751                  * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
 1752                  * and save the error in the nfsnode. This is less than ideal 
 1753                  * but necessary. Keeping such buffers around could potentially
 1754                  * cause buffer exhaustion eventually (they can never be written
 1755                  * out, so will get constantly be re-dirtied). It also causes
 1756                  * all sorts of vfs panics. For non-recoverable write errors, 
 1757                  * also invalidate the attrcache, so we'll be forced to go over
 1758                  * the wire for this object, returning an error to user on next
 1759                  * call (most of the time).
 1760                  */
 1761                 if (error == EINTR || error == EIO || error == ETIMEDOUT
 1762                     || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
 1763                         int s;
 1764 
 1765                         s = splbio();
 1766                         bp->b_flags &= ~(B_INVAL|B_NOCACHE);
 1767                         if ((bp->b_flags & B_PAGING) == 0) {
 1768                             bdirty(bp);
 1769                             bp->b_flags &= ~B_DONE;
 1770                         }
 1771                         if ((error == EINTR || error == ETIMEDOUT) &&
 1772                             (bp->b_flags & B_ASYNC) == 0)
 1773                             bp->b_flags |= B_EINTR;
 1774                         splx(s);
 1775                 } else {
 1776                     if (error) {
 1777                         bp->b_ioflags |= BIO_ERROR;
 1778                         bp->b_flags |= B_INVAL;
 1779                         bp->b_error = np->n_error = error;
 1780                         mtx_lock(&np->n_mtx);
 1781                         np->n_flag |= NWRITEERR;
 1782                         np->n_attrstamp = 0;
 1783                         mtx_unlock(&np->n_mtx);
 1784                     }
 1785                     bp->b_dirtyoff = bp->b_dirtyend = 0;
 1786                 }
 1787             } else {
 1788                 bp->b_resid = 0;
 1789                 bufdone(bp);
 1790                 return (0);
 1791             }
 1792         }
 1793         bp->b_resid = uiop->uio_resid;
 1794         if (must_commit)
 1795             ncl_clearcommit(vp->v_mount);
 1796         bufdone(bp);
 1797         return (error);
 1798 }
 1799 
 1800 /*
 1801  * Used to aid in handling ftruncate() operations on the NFS client side.
 1802  * Truncation creates a number of special problems for NFS.  We have to
 1803  * throw away VM pages and buffer cache buffers that are beyond EOF, and
 1804  * we have to properly handle VM pages or (potentially dirty) buffers
 1805  * that straddle the truncation point.
 1806  */
 1807 
 1808 int
 1809 ncl_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
 1810 {
 1811         struct nfsnode *np = VTONFS(vp);
 1812         u_quad_t tsize;
 1813         int biosize = vp->v_mount->mnt_stat.f_iosize;
 1814         int error = 0;
 1815 
 1816         mtx_lock(&np->n_mtx);
 1817         tsize = np->n_size;
 1818         np->n_size = nsize;
 1819         mtx_unlock(&np->n_mtx);
 1820 
 1821         if (nsize < tsize) {
 1822                 struct buf *bp;
 1823                 daddr_t lbn;
 1824                 int bufsize;
 1825 
 1826                 /*
 1827                  * vtruncbuf() doesn't get the buffer overlapping the 
 1828                  * truncation point.  We may have a B_DELWRI and/or B_CACHE
 1829                  * buffer that now needs to be truncated.
 1830                  */
 1831                 error = vtruncbuf(vp, cred, td, nsize, biosize);
 1832                 lbn = nsize / biosize;
 1833                 bufsize = nsize & (biosize - 1);
 1834                 bp = nfs_getcacheblk(vp, lbn, bufsize, td);
 1835                 if (!bp)
 1836                         return EINTR;
 1837                 if (bp->b_dirtyoff > bp->b_bcount)
 1838                         bp->b_dirtyoff = bp->b_bcount;
 1839                 if (bp->b_dirtyend > bp->b_bcount)
 1840                         bp->b_dirtyend = bp->b_bcount;
 1841                 bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
 1842                 brelse(bp);
 1843         } else {
 1844                 vnode_pager_setsize(vp, nsize);
 1845         }
 1846         return(error);
 1847 }
 1848 

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