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: stable/8/sys/fs/nfsclient/nfs_clbio.c 251768 2013-06-15 01:35:52Z 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/vmmeter.h>
   45 #include <sys/vnode.h>
   46 
   47 #include <vm/vm.h>
   48 #include <vm/vm_extern.h>
   49 #include <vm/vm_page.h>
   50 #include <vm/vm_object.h>
   51 #include <vm/vm_pager.h>
   52 #include <vm/vnode_pager.h>
   53 
   54 #include <fs/nfs/nfsport.h>
   55 #include <fs/nfsclient/nfsmount.h>
   56 #include <fs/nfsclient/nfs.h>
   57 #include <fs/nfsclient/nfsnode.h>
   58 
   59 extern int newnfs_directio_allow_mmap;
   60 extern struct nfsstats newnfsstats;
   61 extern struct mtx ncl_iod_mutex;
   62 extern int ncl_numasync;
   63 extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
   64 extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
   65 extern int newnfs_directio_enable;
   66 extern int newnfs_keep_dirty_on_error;
   67 
   68 int ncl_pbuf_freecnt = -1;      /* start out unlimited */
   69 
   70 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
   71     struct thread *td);
   72 static int nfs_directio_write(struct vnode *vp, struct uio *uiop, 
   73     struct ucred *cred, int ioflag);
   74 
   75 /*
   76  * Vnode op for VM getpages.
   77  */
   78 int
   79 ncl_getpages(struct vop_getpages_args *ap)
   80 {
   81         int i, error, nextoff, size, toff, count, npages;
   82         struct uio uio;
   83         struct iovec iov;
   84         vm_offset_t kva;
   85         struct buf *bp;
   86         struct vnode *vp;
   87         struct thread *td;
   88         struct ucred *cred;
   89         struct nfsmount *nmp;
   90         vm_object_t object;
   91         vm_page_t *pages;
   92         struct nfsnode *np;
   93 
   94         vp = ap->a_vp;
   95         np = VTONFS(vp);
   96         td = curthread;                         /* XXX */
   97         cred = curthread->td_ucred;             /* XXX */
   98         nmp = VFSTONFS(vp->v_mount);
   99         pages = ap->a_m;
  100         count = ap->a_count;
  101 
  102         if ((object = vp->v_object) == NULL) {
  103                 ncl_printf("nfs_getpages: called with non-merged cache vnode??\n");
  104                 return (VM_PAGER_ERROR);
  105         }
  106 
  107         if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
  108                 mtx_lock(&np->n_mtx);
  109                 if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  110                         mtx_unlock(&np->n_mtx);
  111                         ncl_printf("nfs_getpages: called on non-cacheable vnode??\n");
  112                         return (VM_PAGER_ERROR);
  113                 } else
  114                         mtx_unlock(&np->n_mtx);
  115         }
  116 
  117         mtx_lock(&nmp->nm_mtx);
  118         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  119             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {  
  120                 mtx_unlock(&nmp->nm_mtx);
  121                 /* We'll never get here for v4, because we always have fsinfo */
  122                 (void)ncl_fsinfo(nmp, vp, cred, td);
  123         } else
  124                 mtx_unlock(&nmp->nm_mtx);
  125 
  126         npages = btoc(count);
  127 
  128         /*
  129          * If the requested page is partially valid, just return it and
  130          * allow the pager to zero-out the blanks.  Partially valid pages
  131          * can only occur at the file EOF.
  132          */
  133         VM_OBJECT_LOCK(object);
  134         if (pages[ap->a_reqpage]->valid != 0) {
  135                 vm_page_lock_queues();
  136                 for (i = 0; i < npages; ++i) {
  137                         if (i != ap->a_reqpage)
  138                                 vm_page_free(pages[i]);
  139                 }
  140                 vm_page_unlock_queues();
  141                 VM_OBJECT_UNLOCK(object);
  142                 return (0);
  143         }
  144         VM_OBJECT_UNLOCK(object);
  145 
  146         /*
  147          * We use only the kva address for the buffer, but this is extremely
  148          * convienient and fast.
  149          */
  150         bp = getpbuf(&ncl_pbuf_freecnt);
  151 
  152         kva = (vm_offset_t) bp->b_data;
  153         pmap_qenter(kva, pages, npages);
  154         PCPU_INC(cnt.v_vnodein);
  155         PCPU_ADD(cnt.v_vnodepgsin, npages);
  156 
  157         iov.iov_base = (caddr_t) kva;
  158         iov.iov_len = count;
  159         uio.uio_iov = &iov;
  160         uio.uio_iovcnt = 1;
  161         uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
  162         uio.uio_resid = count;
  163         uio.uio_segflg = UIO_SYSSPACE;
  164         uio.uio_rw = UIO_READ;
  165         uio.uio_td = td;
  166 
  167         error = ncl_readrpc(vp, &uio, cred);
  168         pmap_qremove(kva, npages);
  169 
  170         relpbuf(bp, &ncl_pbuf_freecnt);
  171 
  172         if (error && (uio.uio_resid == count)) {
  173                 ncl_printf("nfs_getpages: error %d\n", error);
  174                 VM_OBJECT_LOCK(object);
  175                 vm_page_lock_queues();
  176                 for (i = 0; i < npages; ++i) {
  177                         if (i != ap->a_reqpage)
  178                                 vm_page_free(pages[i]);
  179                 }
  180                 vm_page_unlock_queues();
  181                 VM_OBJECT_UNLOCK(object);
  182                 return (VM_PAGER_ERROR);
  183         }
  184 
  185         /*
  186          * Calculate the number of bytes read and validate only that number
  187          * of bytes.  Note that due to pending writes, size may be 0.  This
  188          * does not mean that the remaining data is invalid!
  189          */
  190 
  191         size = count - uio.uio_resid;
  192         VM_OBJECT_LOCK(object);
  193         vm_page_lock_queues();
  194         for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
  195                 vm_page_t m;
  196                 nextoff = toff + PAGE_SIZE;
  197                 m = pages[i];
  198 
  199                 if (nextoff <= size) {
  200                         /*
  201                          * Read operation filled an entire page
  202                          */
  203                         m->valid = VM_PAGE_BITS_ALL;
  204                         KASSERT(m->dirty == 0,
  205                             ("nfs_getpages: page %p is dirty", m));
  206                 } else if (size > toff) {
  207                         /*
  208                          * Read operation filled a partial page.
  209                          */
  210                         m->valid = 0;
  211                         vm_page_set_valid(m, 0, size - toff);
  212                         KASSERT(m->dirty == 0,
  213                             ("nfs_getpages: page %p is dirty", m));
  214                 } else {
  215                         /*
  216                          * Read operation was short.  If no error occured
  217                          * we may have hit a zero-fill section.   We simply
  218                          * leave valid set to 0.
  219                          */
  220                         ;
  221                 }
  222                 if (i != ap->a_reqpage) {
  223                         /*
  224                          * Whether or not to leave the page activated is up in
  225                          * the air, but we should put the page on a page queue
  226                          * somewhere (it already is in the object).  Result:
  227                          * It appears that emperical results show that
  228                          * deactivating pages is best.
  229                          */
  230 
  231                         /*
  232                          * Just in case someone was asking for this page we
  233                          * now tell them that it is ok to use.
  234                          */
  235                         if (!error) {
  236                                 if (m->oflags & VPO_WANTED)
  237                                         vm_page_activate(m);
  238                                 else
  239                                         vm_page_deactivate(m);
  240                                 vm_page_wakeup(m);
  241                         } else {
  242                                 vm_page_free(m);
  243                         }
  244                 }
  245         }
  246         vm_page_unlock_queues();
  247         VM_OBJECT_UNLOCK(object);
  248         return (0);
  249 }
  250 
  251 /*
  252  * Vnode op for VM putpages.
  253  */
  254 int
  255 ncl_putpages(struct vop_putpages_args *ap)
  256 {
  257         struct uio uio;
  258         struct iovec iov;
  259         vm_offset_t kva;
  260         struct buf *bp;
  261         int iomode, must_commit, i, error, npages, count;
  262         off_t offset;
  263         int *rtvals;
  264         struct vnode *vp;
  265         struct thread *td;
  266         struct ucred *cred;
  267         struct nfsmount *nmp;
  268         struct nfsnode *np;
  269         vm_page_t *pages;
  270 
  271         vp = ap->a_vp;
  272         np = VTONFS(vp);
  273         td = curthread;                         /* XXX */
  274         /* Set the cred to n_writecred for the write rpcs. */
  275         if (np->n_writecred != NULL)
  276                 cred = crhold(np->n_writecred);
  277         else
  278                 cred = crhold(curthread->td_ucred);     /* XXX */
  279         nmp = VFSTONFS(vp->v_mount);
  280         pages = ap->a_m;
  281         count = ap->a_count;
  282         rtvals = ap->a_rtvals;
  283         npages = btoc(count);
  284         offset = IDX_TO_OFF(pages[0]->pindex);
  285         
  286         mtx_lock(&nmp->nm_mtx);
  287         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  288             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  289                 mtx_unlock(&nmp->nm_mtx);
  290                 (void)ncl_fsinfo(nmp, vp, cred, td);
  291         } else
  292                 mtx_unlock(&nmp->nm_mtx);
  293 
  294         mtx_lock(&np->n_mtx);
  295         if (newnfs_directio_enable && !newnfs_directio_allow_mmap && 
  296             (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  297                 mtx_unlock(&np->n_mtx);         
  298                 ncl_printf("ncl_putpages: called on noncache-able vnode??\n");
  299                 mtx_lock(&np->n_mtx);
  300         }
  301 
  302         for (i = 0; i < npages; i++)
  303                 rtvals[i] = VM_PAGER_ERROR;
  304 
  305         /*
  306          * When putting pages, do not extend file past EOF.
  307          */
  308         if (offset + count > np->n_size) {
  309                 count = np->n_size - offset;
  310                 if (count < 0)
  311                         count = 0;
  312         }
  313         mtx_unlock(&np->n_mtx);
  314 
  315         /*
  316          * We use only the kva address for the buffer, but this is extremely
  317          * convienient and fast.
  318          */
  319         bp = getpbuf(&ncl_pbuf_freecnt);
  320 
  321         kva = (vm_offset_t) bp->b_data;
  322         pmap_qenter(kva, pages, npages);
  323         PCPU_INC(cnt.v_vnodeout);
  324         PCPU_ADD(cnt.v_vnodepgsout, count);
  325 
  326         iov.iov_base = (caddr_t) kva;
  327         iov.iov_len = count;
  328         uio.uio_iov = &iov;
  329         uio.uio_iovcnt = 1;
  330         uio.uio_offset = offset;
  331         uio.uio_resid = count;
  332         uio.uio_segflg = UIO_SYSSPACE;
  333         uio.uio_rw = UIO_WRITE;
  334         uio.uio_td = td;
  335 
  336         if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
  337             iomode = NFSWRITE_UNSTABLE;
  338         else
  339             iomode = NFSWRITE_FILESYNC;
  340 
  341         error = ncl_writerpc(vp, &uio, cred, &iomode, &must_commit, 0);
  342         crfree(cred);
  343 
  344         pmap_qremove(kva, npages);
  345         relpbuf(bp, &ncl_pbuf_freecnt);
  346 
  347         if (error == 0 || !newnfs_keep_dirty_on_error) {
  348                 vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid);
  349                 if (must_commit)
  350                         ncl_clearcommit(vp->v_mount);
  351         }
  352         return rtvals[0];
  353 }
  354 
  355 /*
  356  * For nfs, cache consistency can only be maintained approximately.
  357  * Although RFC1094 does not specify the criteria, the following is
  358  * believed to be compatible with the reference port.
  359  * For nfs:
  360  * If the file's modify time on the server has changed since the
  361  * last read rpc or you have written to the file,
  362  * you may have lost data cache consistency with the
  363  * server, so flush all of the file's data out of the cache.
  364  * Then force a getattr rpc to ensure that you have up to date
  365  * attributes.
  366  * NB: This implies that cache data can be read when up to
  367  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
  368  * attributes this could be forced by setting n_attrstamp to 0 before
  369  * the VOP_GETATTR() call.
  370  */
  371 static inline int
  372 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
  373 {
  374         int error = 0;
  375         struct vattr vattr;
  376         struct nfsnode *np = VTONFS(vp);
  377         int old_lock;
  378         
  379         /*
  380          * Grab the exclusive lock before checking whether the cache is
  381          * consistent.
  382          * XXX - We can make this cheaper later (by acquiring cheaper locks).
  383          * But for now, this suffices.
  384          */
  385         old_lock = ncl_upgrade_vnlock(vp);
  386         if (vp->v_iflag & VI_DOOMED) {
  387                 ncl_downgrade_vnlock(vp, old_lock);
  388                 return (EBADF);
  389         }
  390 
  391         mtx_lock(&np->n_mtx);
  392         if (np->n_flag & NMODIFIED) {
  393                 mtx_unlock(&np->n_mtx);
  394                 if (vp->v_type != VREG) {
  395                         if (vp->v_type != VDIR)
  396                                 panic("nfs: bioread, not dir");
  397                         ncl_invaldir(vp);
  398                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  399                         if (error)
  400                                 goto out;
  401                 }
  402                 np->n_attrstamp = 0;
  403                 error = VOP_GETATTR(vp, &vattr, cred);
  404                 if (error)
  405                         goto out;
  406                 mtx_lock(&np->n_mtx);
  407                 np->n_mtime = vattr.va_mtime;
  408                 mtx_unlock(&np->n_mtx);
  409         } else {
  410                 mtx_unlock(&np->n_mtx);
  411                 error = VOP_GETATTR(vp, &vattr, cred);
  412                 if (error)
  413                         return (error);
  414                 mtx_lock(&np->n_mtx);
  415                 if ((np->n_flag & NSIZECHANGED)
  416                     || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
  417                         mtx_unlock(&np->n_mtx);
  418                         if (vp->v_type == VDIR)
  419                                 ncl_invaldir(vp);
  420                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  421                         if (error)
  422                                 goto out;
  423                         mtx_lock(&np->n_mtx);
  424                         np->n_mtime = vattr.va_mtime;
  425                         np->n_flag &= ~NSIZECHANGED;
  426                 }
  427                 mtx_unlock(&np->n_mtx);
  428         }
  429 out:    
  430         ncl_downgrade_vnlock(vp, old_lock);
  431         return error;
  432 }
  433 
  434 /*
  435  * Vnode op for read using bio
  436  */
  437 int
  438 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
  439 {
  440         struct nfsnode *np = VTONFS(vp);
  441         int biosize, i;
  442         struct buf *bp, *rabp;
  443         struct thread *td;
  444         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  445         daddr_t lbn, rabn;
  446         int bcount;
  447         int seqcount;
  448         int nra, error = 0, n = 0, on = 0;
  449         off_t tmp_off;
  450 
  451         KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
  452         if (uio->uio_resid == 0)
  453                 return (0);
  454         if (uio->uio_offset < 0)        /* XXX VDIR cookies can be negative */
  455                 return (EINVAL);
  456         td = uio->uio_td;
  457 
  458         mtx_lock(&nmp->nm_mtx);
  459         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  460             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  461                 mtx_unlock(&nmp->nm_mtx);
  462                 (void)ncl_fsinfo(nmp, vp, cred, td);
  463                 mtx_lock(&nmp->nm_mtx);
  464         }
  465         if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
  466                 (void) newnfs_iosize(nmp);
  467 
  468         tmp_off = uio->uio_offset + uio->uio_resid;
  469         if (vp->v_type != VDIR &&
  470             (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)) {
  471                 mtx_unlock(&nmp->nm_mtx);               
  472                 return (EFBIG);
  473         }
  474         mtx_unlock(&nmp->nm_mtx);               
  475 
  476         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
  477                 /* No caching/ no readaheads. Just read data into the user buffer */
  478                 return ncl_readrpc(vp, uio, cred);
  479 
  480         biosize = vp->v_bufobj.bo_bsize;
  481         seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
  482         
  483         error = nfs_bioread_check_cons(vp, td, cred);
  484         if (error)
  485                 return error;
  486 
  487         do {
  488             u_quad_t nsize;
  489                         
  490             mtx_lock(&np->n_mtx);
  491             nsize = np->n_size;
  492             mtx_unlock(&np->n_mtx);                 
  493 
  494             switch (vp->v_type) {
  495             case VREG:
  496                 NFSINCRGLOBAL(newnfsstats.biocache_reads);
  497                 lbn = uio->uio_offset / biosize;
  498                 on = uio->uio_offset & (biosize - 1);
  499 
  500                 /*
  501                  * Start the read ahead(s), as required.
  502                  */
  503                 if (nmp->nm_readahead > 0) {
  504                     for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
  505                         (off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
  506                         rabn = lbn + 1 + nra;
  507                         if (incore(&vp->v_bufobj, rabn) == NULL) {
  508                             rabp = nfs_getcacheblk(vp, rabn, biosize, td);
  509                             if (!rabp) {
  510                                 error = newnfs_sigintr(nmp, td);
  511                                 return (error ? error : EINTR);
  512                             }
  513                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  514                                 rabp->b_flags |= B_ASYNC;
  515                                 rabp->b_iocmd = BIO_READ;
  516                                 vfs_busy_pages(rabp, 0);
  517                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  518                                     rabp->b_flags |= B_INVAL;
  519                                     rabp->b_ioflags |= BIO_ERROR;
  520                                     vfs_unbusy_pages(rabp);
  521                                     brelse(rabp);
  522                                     break;
  523                                 }
  524                             } else {
  525                                 brelse(rabp);
  526                             }
  527                         }
  528                     }
  529                 }
  530 
  531                 /* Note that bcount is *not* DEV_BSIZE aligned. */
  532                 bcount = biosize;
  533                 if ((off_t)lbn * biosize >= nsize) {
  534                         bcount = 0;
  535                 } else if ((off_t)(lbn + 1) * biosize > nsize) {
  536                         bcount = nsize - (off_t)lbn * biosize;
  537                 }
  538                 bp = nfs_getcacheblk(vp, lbn, bcount, td);
  539 
  540                 if (!bp) {
  541                         error = newnfs_sigintr(nmp, td);
  542                         return (error ? error : EINTR);
  543                 }
  544 
  545                 /*
  546                  * If B_CACHE is not set, we must issue the read.  If this
  547                  * fails, we return an error.
  548                  */
  549 
  550                 if ((bp->b_flags & B_CACHE) == 0) {
  551                     bp->b_iocmd = BIO_READ;
  552                     vfs_busy_pages(bp, 0);
  553                     error = ncl_doio(vp, bp, cred, td, 0);
  554                     if (error) {
  555                         brelse(bp);
  556                         return (error);
  557                     }
  558                 }
  559 
  560                 /*
  561                  * on is the offset into the current bp.  Figure out how many
  562                  * bytes we can copy out of the bp.  Note that bcount is
  563                  * NOT DEV_BSIZE aligned.
  564                  *
  565                  * Then figure out how many bytes we can copy into the uio.
  566                  */
  567 
  568                 n = 0;
  569                 if (on < bcount)
  570                         n = min((unsigned)(bcount - on), uio->uio_resid);
  571                 break;
  572             case VLNK:
  573                 NFSINCRGLOBAL(newnfsstats.biocache_readlinks);
  574                 bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
  575                 if (!bp) {
  576                         error = newnfs_sigintr(nmp, td);
  577                         return (error ? error : EINTR);
  578                 }
  579                 if ((bp->b_flags & B_CACHE) == 0) {
  580                     bp->b_iocmd = BIO_READ;
  581                     vfs_busy_pages(bp, 0);
  582                     error = ncl_doio(vp, bp, cred, td, 0);
  583                     if (error) {
  584                         bp->b_ioflags |= BIO_ERROR;
  585                         brelse(bp);
  586                         return (error);
  587                     }
  588                 }
  589                 n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
  590                 on = 0;
  591                 break;
  592             case VDIR:
  593                 NFSINCRGLOBAL(newnfsstats.biocache_readdirs);
  594                 if (np->n_direofoffset
  595                     && uio->uio_offset >= np->n_direofoffset) {
  596                     return (0);
  597                 }
  598                 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
  599                 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
  600                 bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
  601                 if (!bp) {
  602                     error = newnfs_sigintr(nmp, td);
  603                     return (error ? error : EINTR);
  604                 }
  605                 if ((bp->b_flags & B_CACHE) == 0) {
  606                     bp->b_iocmd = BIO_READ;
  607                     vfs_busy_pages(bp, 0);
  608                     error = ncl_doio(vp, bp, cred, td, 0);
  609                     if (error) {
  610                             brelse(bp);
  611                     }
  612                     while (error == NFSERR_BAD_COOKIE) {
  613                         ncl_invaldir(vp);
  614                         error = ncl_vinvalbuf(vp, 0, td, 1);
  615                         /*
  616                          * Yuck! The directory has been modified on the
  617                          * server. The only way to get the block is by
  618                          * reading from the beginning to get all the
  619                          * offset cookies.
  620                          *
  621                          * Leave the last bp intact unless there is an error.
  622                          * Loop back up to the while if the error is another
  623                          * NFSERR_BAD_COOKIE (double yuch!).
  624                          */
  625                         for (i = 0; i <= lbn && !error; i++) {
  626                             if (np->n_direofoffset
  627                                 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
  628                                     return (0);
  629                             bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
  630                             if (!bp) {
  631                                 error = newnfs_sigintr(nmp, td);
  632                                 return (error ? error : EINTR);
  633                             }
  634                             if ((bp->b_flags & B_CACHE) == 0) {
  635                                     bp->b_iocmd = BIO_READ;
  636                                     vfs_busy_pages(bp, 0);
  637                                     error = ncl_doio(vp, bp, cred, td, 0);
  638                                     /*
  639                                      * no error + B_INVAL == directory EOF,
  640                                      * use the block.
  641                                      */
  642                                     if (error == 0 && (bp->b_flags & B_INVAL))
  643                                             break;
  644                             }
  645                             /*
  646                              * An error will throw away the block and the
  647                              * for loop will break out.  If no error and this
  648                              * is not the block we want, we throw away the
  649                              * block and go for the next one via the for loop.
  650                              */
  651                             if (error || i < lbn)
  652                                     brelse(bp);
  653                         }
  654                     }
  655                     /*
  656                      * The above while is repeated if we hit another cookie
  657                      * error.  If we hit an error and it wasn't a cookie error,
  658                      * we give up.
  659                      */
  660                     if (error)
  661                             return (error);
  662                 }
  663 
  664                 /*
  665                  * If not eof and read aheads are enabled, start one.
  666                  * (You need the current block first, so that you have the
  667                  *  directory offset cookie of the next block.)
  668                  */
  669                 if (nmp->nm_readahead > 0 &&
  670                     (bp->b_flags & B_INVAL) == 0 &&
  671                     (np->n_direofoffset == 0 ||
  672                     (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
  673                     incore(&vp->v_bufobj, lbn + 1) == NULL) {
  674                         rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
  675                         if (rabp) {
  676                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  677                                 rabp->b_flags |= B_ASYNC;
  678                                 rabp->b_iocmd = BIO_READ;
  679                                 vfs_busy_pages(rabp, 0);
  680                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  681                                     rabp->b_flags |= B_INVAL;
  682                                     rabp->b_ioflags |= BIO_ERROR;
  683                                     vfs_unbusy_pages(rabp);
  684                                     brelse(rabp);
  685                                 }
  686                             } else {
  687                                 brelse(rabp);
  688                             }
  689                         }
  690                 }
  691                 /*
  692                  * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
  693                  * chopped for the EOF condition, we cannot tell how large
  694                  * NFS directories are going to be until we hit EOF.  So
  695                  * an NFS directory buffer is *not* chopped to its EOF.  Now,
  696                  * it just so happens that b_resid will effectively chop it
  697                  * to EOF.  *BUT* this information is lost if the buffer goes
  698                  * away and is reconstituted into a B_CACHE state ( due to
  699                  * being VMIO ) later.  So we keep track of the directory eof
  700                  * in np->n_direofoffset and chop it off as an extra step
  701                  * right here.
  702                  */
  703                 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
  704                 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
  705                         n = np->n_direofoffset - uio->uio_offset;
  706                 break;
  707             default:
  708                 ncl_printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
  709                 bp = NULL;
  710                 break;
  711             };
  712 
  713             if (n > 0) {
  714                     error = uiomove(bp->b_data + on, (int)n, uio);
  715             }
  716             if (vp->v_type == VLNK)
  717                 n = 0;
  718             if (bp != NULL)
  719                 brelse(bp);
  720         } while (error == 0 && uio->uio_resid > 0 && n > 0);
  721         return (error);
  722 }
  723 
  724 /*
  725  * The NFS write path cannot handle iovecs with len > 1. So we need to 
  726  * break up iovecs accordingly (restricting them to wsize).
  727  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf). 
  728  * For the ASYNC case, 2 copies are needed. The first a copy from the 
  729  * user buffer to a staging buffer and then a second copy from the staging
  730  * buffer to mbufs. This can be optimized by copying from the user buffer
  731  * directly into mbufs and passing the chain down, but that requires a 
  732  * fair amount of re-working of the relevant codepaths (and can be done
  733  * later).
  734  */
  735 static int
  736 nfs_directio_write(vp, uiop, cred, ioflag)
  737         struct vnode *vp;
  738         struct uio *uiop;
  739         struct ucred *cred;
  740         int ioflag;
  741 {
  742         int error;
  743         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  744         struct thread *td = uiop->uio_td;
  745         int size;
  746         int wsize;
  747         
  748         mtx_lock(&nmp->nm_mtx);
  749         wsize = nmp->nm_wsize;
  750         mtx_unlock(&nmp->nm_mtx);
  751         if (ioflag & IO_SYNC) {
  752                 int iomode, must_commit;
  753                 struct uio uio;
  754                 struct iovec iov;
  755 do_sync:
  756                 while (uiop->uio_resid > 0) {
  757                         size = min(uiop->uio_resid, wsize);
  758                         size = min(uiop->uio_iov->iov_len, size);
  759                         iov.iov_base = uiop->uio_iov->iov_base;
  760                         iov.iov_len = size;
  761                         uio.uio_iov = &iov;
  762                         uio.uio_iovcnt = 1;
  763                         uio.uio_offset = uiop->uio_offset;
  764                         uio.uio_resid = size;
  765                         uio.uio_segflg = UIO_USERSPACE;
  766                         uio.uio_rw = UIO_WRITE;
  767                         uio.uio_td = td;
  768                         iomode = NFSWRITE_FILESYNC;
  769                         error = ncl_writerpc(vp, &uio, cred, &iomode,
  770                             &must_commit, 0);
  771                         KASSERT((must_commit == 0), 
  772                                 ("ncl_directio_write: Did not commit write"));
  773                         if (error)
  774                                 return (error);
  775                         uiop->uio_offset += size;
  776                         uiop->uio_resid -= size;
  777                         if (uiop->uio_iov->iov_len <= size) {
  778                                 uiop->uio_iovcnt--;
  779                                 uiop->uio_iov++;
  780                         } else {
  781                                 uiop->uio_iov->iov_base = 
  782                                         (char *)uiop->uio_iov->iov_base + size;
  783                                 uiop->uio_iov->iov_len -= size;
  784                         }
  785                 }
  786         } else {
  787                 struct uio *t_uio;
  788                 struct iovec *t_iov;
  789                 struct buf *bp;
  790                 
  791                 /*
  792                  * Break up the write into blocksize chunks and hand these
  793                  * over to nfsiod's for write back.
  794                  * Unfortunately, this incurs a copy of the data. Since 
  795                  * the user could modify the buffer before the write is 
  796                  * initiated.
  797                  * 
  798                  * The obvious optimization here is that one of the 2 copies
  799                  * in the async write path can be eliminated by copying the
  800                  * data here directly into mbufs and passing the mbuf chain
  801                  * down. But that will require a fair amount of re-working
  802                  * of the code and can be done if there's enough interest
  803                  * in NFS directio access.
  804                  */
  805                 while (uiop->uio_resid > 0) {
  806                         size = min(uiop->uio_resid, wsize);
  807                         size = min(uiop->uio_iov->iov_len, size);
  808                         bp = getpbuf(&ncl_pbuf_freecnt);
  809                         t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
  810                         t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
  811                         t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
  812                         t_iov->iov_len = size;
  813                         t_uio->uio_iov = t_iov;
  814                         t_uio->uio_iovcnt = 1;
  815                         t_uio->uio_offset = uiop->uio_offset;
  816                         t_uio->uio_resid = size;
  817                         t_uio->uio_segflg = UIO_SYSSPACE;
  818                         t_uio->uio_rw = UIO_WRITE;
  819                         t_uio->uio_td = td;
  820                         KASSERT(uiop->uio_segflg == UIO_USERSPACE ||
  821                             uiop->uio_segflg == UIO_SYSSPACE,
  822                             ("nfs_directio_write: Bad uio_segflg"));
  823                         if (uiop->uio_segflg == UIO_USERSPACE) {
  824                                 error = copyin(uiop->uio_iov->iov_base,
  825                                     t_iov->iov_base, size);
  826                                 if (error != 0)
  827                                         goto err_free;
  828                         } else
  829                                 /*
  830                                  * UIO_SYSSPACE may never happen, but handle
  831                                  * it just in case it does.
  832                                  */
  833                                 bcopy(uiop->uio_iov->iov_base, t_iov->iov_base,
  834                                     size);
  835                         bp->b_flags |= B_DIRECT;
  836                         bp->b_iocmd = BIO_WRITE;
  837                         if (cred != NOCRED) {
  838                                 crhold(cred);
  839                                 bp->b_wcred = cred;
  840                         } else 
  841                                 bp->b_wcred = NOCRED;                   
  842                         bp->b_caller1 = (void *)t_uio;
  843                         bp->b_vp = vp;
  844                         error = ncl_asyncio(nmp, bp, NOCRED, td);
  845 err_free:
  846                         if (error) {
  847                                 free(t_iov->iov_base, M_NFSDIRECTIO);
  848                                 free(t_iov, M_NFSDIRECTIO);
  849                                 free(t_uio, M_NFSDIRECTIO);
  850                                 bp->b_vp = NULL;
  851                                 relpbuf(bp, &ncl_pbuf_freecnt);
  852                                 if (error == EINTR)
  853                                         return (error);
  854                                 goto do_sync;
  855                         }
  856                         uiop->uio_offset += size;
  857                         uiop->uio_resid -= size;
  858                         if (uiop->uio_iov->iov_len <= size) {
  859                                 uiop->uio_iovcnt--;
  860                                 uiop->uio_iov++;
  861                         } else {
  862                                 uiop->uio_iov->iov_base = 
  863                                         (char *)uiop->uio_iov->iov_base + size;
  864                                 uiop->uio_iov->iov_len -= size;
  865                         }
  866                 }
  867         }
  868         return (0);
  869 }
  870 
  871 /*
  872  * Vnode op for write using bio
  873  */
  874 int
  875 ncl_write(struct vop_write_args *ap)
  876 {
  877         int biosize;
  878         struct uio *uio = ap->a_uio;
  879         struct thread *td = uio->uio_td;
  880         struct vnode *vp = ap->a_vp;
  881         struct nfsnode *np = VTONFS(vp);
  882         struct ucred *cred = ap->a_cred;
  883         int ioflag = ap->a_ioflag;
  884         struct buf *bp;
  885         struct vattr vattr;
  886         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  887         daddr_t lbn;
  888         int bcount;
  889         int n, on, error = 0;
  890         off_t tmp_off;
  891 
  892         KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
  893         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  894             ("ncl_write proc"));
  895         if (vp->v_type != VREG)
  896                 return (EIO);
  897         mtx_lock(&np->n_mtx);
  898         if (np->n_flag & NWRITEERR) {
  899                 np->n_flag &= ~NWRITEERR;
  900                 mtx_unlock(&np->n_mtx);
  901                 return (np->n_error);
  902         } else
  903                 mtx_unlock(&np->n_mtx);
  904         mtx_lock(&nmp->nm_mtx);
  905         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  906             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  907                 mtx_unlock(&nmp->nm_mtx);
  908                 (void)ncl_fsinfo(nmp, vp, cred, td);
  909                 mtx_lock(&nmp->nm_mtx);
  910         }
  911         if (nmp->nm_wsize == 0)
  912                 (void) newnfs_iosize(nmp);
  913         mtx_unlock(&nmp->nm_mtx);
  914 
  915         /*
  916          * Synchronously flush pending buffers if we are in synchronous
  917          * mode or if we are appending.
  918          */
  919         if (ioflag & (IO_APPEND | IO_SYNC)) {
  920                 mtx_lock(&np->n_mtx);
  921                 if (np->n_flag & NMODIFIED) {
  922                         mtx_unlock(&np->n_mtx);
  923 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
  924                         /*
  925                          * Require non-blocking, synchronous writes to
  926                          * dirty files to inform the program it needs
  927                          * to fsync(2) explicitly.
  928                          */
  929                         if (ioflag & IO_NDELAY)
  930                                 return (EAGAIN);
  931 #endif
  932 flush_and_restart:
  933                         np->n_attrstamp = 0;
  934                         error = ncl_vinvalbuf(vp, V_SAVE, td, 1);
  935                         if (error)
  936                                 return (error);
  937                 } else
  938                         mtx_unlock(&np->n_mtx);
  939         }
  940 
  941         /*
  942          * If IO_APPEND then load uio_offset.  We restart here if we cannot
  943          * get the append lock.
  944          */
  945         if (ioflag & IO_APPEND) {
  946                 np->n_attrstamp = 0;
  947                 error = VOP_GETATTR(vp, &vattr, cred);
  948                 if (error)
  949                         return (error);
  950                 mtx_lock(&np->n_mtx);
  951                 uio->uio_offset = np->n_size;
  952                 mtx_unlock(&np->n_mtx);
  953         }
  954 
  955         if (uio->uio_offset < 0)
  956                 return (EINVAL);
  957         tmp_off = uio->uio_offset + uio->uio_resid;
  958         if (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)
  959                 return (EFBIG);
  960         if (uio->uio_resid == 0)
  961                 return (0);
  962 
  963         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
  964                 return nfs_directio_write(vp, uio, cred, ioflag);
  965 
  966         /*
  967          * Maybe this should be above the vnode op call, but so long as
  968          * file servers have no limits, i don't think it matters
  969          */
  970         if (vn_rlimit_fsize(vp, uio, td))
  971                 return (EFBIG);
  972 
  973         biosize = vp->v_bufobj.bo_bsize;
  974         /*
  975          * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
  976          * would exceed the local maximum per-file write commit size when
  977          * combined with those, we must decide whether to flush,
  978          * go synchronous, or return error.  We don't bother checking
  979          * IO_UNIT -- we just make all writes atomic anyway, as there's
  980          * no point optimizing for something that really won't ever happen.
  981          */
  982         if (!(ioflag & IO_SYNC)) {
  983                 int nflag;
  984 
  985                 mtx_lock(&np->n_mtx);
  986                 nflag = np->n_flag;
  987                 mtx_unlock(&np->n_mtx);         
  988                 int needrestart = 0;
  989                 if (nmp->nm_wcommitsize < uio->uio_resid) {
  990                         /*
  991                          * If this request could not possibly be completed
  992                          * without exceeding the maximum outstanding write
  993                          * commit size, see if we can convert it into a
  994                          * synchronous write operation.
  995                          */
  996                         if (ioflag & IO_NDELAY)
  997                                 return (EAGAIN);
  998                         ioflag |= IO_SYNC;
  999                         if (nflag & NMODIFIED)
 1000                                 needrestart = 1;
 1001                 } else if (nflag & NMODIFIED) {
 1002                         int wouldcommit = 0;
 1003                         BO_LOCK(&vp->v_bufobj);
 1004                         if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
 1005                                 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
 1006                                     b_bobufs) {
 1007                                         if (bp->b_flags & B_NEEDCOMMIT)
 1008                                                 wouldcommit += bp->b_bcount;
 1009                                 }
 1010                         }
 1011                         BO_UNLOCK(&vp->v_bufobj);
 1012                         /*
 1013                          * Since we're not operating synchronously and
 1014                          * bypassing the buffer cache, we are in a commit
 1015                          * and holding all of these buffers whether
 1016                          * transmitted or not.  If not limited, this
 1017                          * will lead to the buffer cache deadlocking,
 1018                          * as no one else can flush our uncommitted buffers.
 1019                          */
 1020                         wouldcommit += uio->uio_resid;
 1021                         /*
 1022                          * If we would initially exceed the maximum
 1023                          * outstanding write commit size, flush and restart.
 1024                          */
 1025                         if (wouldcommit > nmp->nm_wcommitsize)
 1026                                 needrestart = 1;
 1027                 }
 1028                 if (needrestart)
 1029                         goto flush_and_restart;
 1030         }
 1031 
 1032         do {
 1033                 NFSINCRGLOBAL(newnfsstats.biocache_writes);
 1034                 lbn = uio->uio_offset / biosize;
 1035                 on = uio->uio_offset & (biosize-1);
 1036                 n = min((unsigned)(biosize - on), uio->uio_resid);
 1037 again:
 1038                 /*
 1039                  * Handle direct append and file extension cases, calculate
 1040                  * unaligned buffer size.
 1041                  */
 1042                 mtx_lock(&np->n_mtx);
 1043                 if (uio->uio_offset == np->n_size && n) {
 1044                         mtx_unlock(&np->n_mtx);
 1045                         /*
 1046                          * Get the buffer (in its pre-append state to maintain
 1047                          * B_CACHE if it was previously set).  Resize the
 1048                          * nfsnode after we have locked the buffer to prevent
 1049                          * readers from reading garbage.
 1050                          */
 1051                         bcount = on;
 1052                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1053 
 1054                         if (bp != NULL) {
 1055                                 long save;
 1056 
 1057                                 mtx_lock(&np->n_mtx);
 1058                                 np->n_size = uio->uio_offset + n;
 1059                                 np->n_flag |= NMODIFIED;
 1060                                 vnode_pager_setsize(vp, np->n_size);
 1061                                 mtx_unlock(&np->n_mtx);
 1062 
 1063                                 save = bp->b_flags & B_CACHE;
 1064                                 bcount += n;
 1065                                 allocbuf(bp, bcount);
 1066                                 bp->b_flags |= save;
 1067                         }
 1068                 } else {
 1069                         /*
 1070                          * Obtain the locked cache block first, and then
 1071                          * adjust the file's size as appropriate.
 1072                          */
 1073                         bcount = on + n;
 1074                         if ((off_t)lbn * biosize + bcount < np->n_size) {
 1075                                 if ((off_t)(lbn + 1) * biosize < np->n_size)
 1076                                         bcount = biosize;
 1077                                 else
 1078                                         bcount = np->n_size - (off_t)lbn * biosize;
 1079                         }
 1080                         mtx_unlock(&np->n_mtx);
 1081                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1082                         mtx_lock(&np->n_mtx);
 1083                         if (uio->uio_offset + n > np->n_size) {
 1084                                 np->n_size = uio->uio_offset + n;
 1085                                 np->n_flag |= NMODIFIED;
 1086                                 vnode_pager_setsize(vp, np->n_size);
 1087                         }
 1088                         mtx_unlock(&np->n_mtx);
 1089                 }
 1090 
 1091                 if (!bp) {
 1092                         error = newnfs_sigintr(nmp, td);
 1093                         if (!error)
 1094                                 error = EINTR;
 1095                         break;
 1096                 }
 1097 
 1098                 /*
 1099                  * Issue a READ if B_CACHE is not set.  In special-append
 1100                  * mode, B_CACHE is based on the buffer prior to the write
 1101                  * op and is typically set, avoiding the read.  If a read
 1102                  * is required in special append mode, the server will
 1103                  * probably send us a short-read since we extended the file
 1104                  * on our end, resulting in b_resid == 0 and, thusly,
 1105                  * B_CACHE getting set.
 1106                  *
 1107                  * We can also avoid issuing the read if the write covers
 1108                  * the entire buffer.  We have to make sure the buffer state
 1109                  * is reasonable in this case since we will not be initiating
 1110                  * I/O.  See the comments in kern/vfs_bio.c's getblk() for
 1111                  * more information.
 1112                  *
 1113                  * B_CACHE may also be set due to the buffer being cached
 1114                  * normally.
 1115                  */
 1116 
 1117                 if (on == 0 && n == bcount) {
 1118                         bp->b_flags |= B_CACHE;
 1119                         bp->b_flags &= ~B_INVAL;
 1120                         bp->b_ioflags &= ~BIO_ERROR;
 1121                 }
 1122 
 1123                 if ((bp->b_flags & B_CACHE) == 0) {
 1124                         bp->b_iocmd = BIO_READ;
 1125                         vfs_busy_pages(bp, 0);
 1126                         error = ncl_doio(vp, bp, cred, td, 0);
 1127                         if (error) {
 1128                                 brelse(bp);
 1129                                 break;
 1130                         }
 1131                 }
 1132                 if (bp->b_wcred == NOCRED)
 1133                         bp->b_wcred = crhold(cred);
 1134                 mtx_lock(&np->n_mtx);
 1135                 np->n_flag |= NMODIFIED;
 1136                 mtx_unlock(&np->n_mtx);
 1137 
 1138                 /*
 1139                  * If dirtyend exceeds file size, chop it down.  This should
 1140                  * not normally occur but there is an append race where it
 1141                  * might occur XXX, so we log it.
 1142                  *
 1143                  * If the chopping creates a reverse-indexed or degenerate
 1144                  * situation with dirtyoff/end, we 0 both of them.
 1145                  */
 1146 
 1147                 if (bp->b_dirtyend > bcount) {
 1148                         ncl_printf("NFS append race @%lx:%d\n",
 1149                             (long)bp->b_blkno * DEV_BSIZE,
 1150                             bp->b_dirtyend - bcount);
 1151                         bp->b_dirtyend = bcount;
 1152                 }
 1153 
 1154                 if (bp->b_dirtyoff >= bp->b_dirtyend)
 1155                         bp->b_dirtyoff = bp->b_dirtyend = 0;
 1156 
 1157                 /*
 1158                  * If the new write will leave a contiguous dirty
 1159                  * area, just update the b_dirtyoff and b_dirtyend,
 1160                  * otherwise force a write rpc of the old dirty area.
 1161                  *
 1162                  * While it is possible to merge discontiguous writes due to
 1163                  * our having a B_CACHE buffer ( and thus valid read data
 1164                  * for the hole), we don't because it could lead to
 1165                  * significant cache coherency problems with multiple clients,
 1166                  * especially if locking is implemented later on.
 1167                  *
 1168                  * As an optimization we could theoretically maintain
 1169                  * a linked list of discontinuous areas, but we would still
 1170                  * have to commit them separately so there isn't much
 1171                  * advantage to it except perhaps a bit of asynchronization.
 1172                  */
 1173 
 1174                 if (bp->b_dirtyend > 0 &&
 1175                     (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
 1176                         if (bwrite(bp) == EINTR) {
 1177                                 error = EINTR;
 1178                                 break;
 1179                         }
 1180                         goto again;
 1181                 }
 1182 
 1183                 error = uiomove((char *)bp->b_data + on, n, uio);
 1184 
 1185                 /*
 1186                  * Since this block is being modified, it must be written
 1187                  * again and not just committed.  Since write clustering does
 1188                  * not work for the stage 1 data write, only the stage 2
 1189                  * commit rpc, we have to clear B_CLUSTEROK as well.
 1190                  */
 1191                 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1192 
 1193                 if (error) {
 1194                         bp->b_ioflags |= BIO_ERROR;
 1195                         brelse(bp);
 1196                         break;
 1197                 }
 1198 
 1199                 /*
 1200                  * Only update dirtyoff/dirtyend if not a degenerate
 1201                  * condition.
 1202                  */
 1203                 if (n) {
 1204                         if (bp->b_dirtyend > 0) {
 1205                                 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
 1206                                 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
 1207                         } else {
 1208                                 bp->b_dirtyoff = on;
 1209                                 bp->b_dirtyend = on + n;
 1210                         }
 1211                         vfs_bio_set_valid(bp, on, n);
 1212                 }
 1213 
 1214                 /*
 1215                  * If IO_SYNC do bwrite().
 1216                  *
 1217                  * IO_INVAL appears to be unused.  The idea appears to be
 1218                  * to turn off caching in this case.  Very odd.  XXX
 1219                  */
 1220                 if ((ioflag & IO_SYNC)) {
 1221                         if (ioflag & IO_INVAL)
 1222                                 bp->b_flags |= B_NOCACHE;
 1223                         error = bwrite(bp);
 1224                         if (error)
 1225                                 break;
 1226                 } else if ((n + on) == biosize) {
 1227                         bp->b_flags |= B_ASYNC;
 1228                         (void) ncl_writebp(bp, 0, NULL);
 1229                 } else {
 1230                         bdwrite(bp);
 1231                 }
 1232         } while (uio->uio_resid > 0 && n > 0);
 1233 
 1234         return (error);
 1235 }
 1236 
 1237 /*
 1238  * Get an nfs cache block.
 1239  *
 1240  * Allocate a new one if the block isn't currently in the cache
 1241  * and return the block marked busy. If the calling process is
 1242  * interrupted by a signal for an interruptible mount point, return
 1243  * NULL.
 1244  *
 1245  * The caller must carefully deal with the possible B_INVAL state of
 1246  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
 1247  * indirectly), so synchronous reads can be issued without worrying about
 1248  * the B_INVAL state.  We have to be a little more careful when dealing
 1249  * with writes (see comments in nfs_write()) when extending a file past
 1250  * its EOF.
 1251  */
 1252 static struct buf *
 1253 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
 1254 {
 1255         struct buf *bp;
 1256         struct mount *mp;
 1257         struct nfsmount *nmp;
 1258 
 1259         mp = vp->v_mount;
 1260         nmp = VFSTONFS(mp);
 1261 
 1262         if (nmp->nm_flag & NFSMNT_INT) {
 1263                 sigset_t oldset;
 1264 
 1265                 newnfs_set_sigmask(td, &oldset);
 1266                 bp = getblk(vp, bn, size, NFS_PCATCH, 0, 0);
 1267                 newnfs_restore_sigmask(td, &oldset);
 1268                 while (bp == NULL) {
 1269                         if (newnfs_sigintr(nmp, td))
 1270                                 return (NULL);
 1271                         bp = getblk(vp, bn, size, 0, 2 * hz, 0);
 1272                 }
 1273         } else {
 1274                 bp = getblk(vp, bn, size, 0, 0, 0);
 1275         }
 1276 
 1277         if (vp->v_type == VREG)
 1278                 bp->b_blkno = bn * (vp->v_bufobj.bo_bsize / DEV_BSIZE);
 1279         return (bp);
 1280 }
 1281 
 1282 /*
 1283  * Flush and invalidate all dirty buffers. If another process is already
 1284  * doing the flush, just wait for completion.
 1285  */
 1286 int
 1287 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
 1288 {
 1289         struct nfsnode *np = VTONFS(vp);
 1290         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 1291         int error = 0, slpflag, slptimeo;
 1292         int old_lock = 0;
 1293 
 1294         ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
 1295 
 1296         if ((nmp->nm_flag & NFSMNT_INT) == 0)
 1297                 intrflg = 0;
 1298         if ((nmp->nm_mountp->mnt_kern_flag & MNTK_UNMOUNTF))
 1299                 intrflg = 1;
 1300         if (intrflg) {
 1301                 slpflag = NFS_PCATCH;
 1302                 slptimeo = 2 * hz;
 1303         } else {
 1304                 slpflag = 0;
 1305                 slptimeo = 0;
 1306         }
 1307 
 1308         old_lock = ncl_upgrade_vnlock(vp);
 1309         if (vp->v_iflag & VI_DOOMED) {
 1310                 /*
 1311                  * Since vgonel() uses the generic vinvalbuf() to flush
 1312                  * dirty buffers and it does not call this function, it
 1313                  * is safe to just return OK when VI_DOOMED is set.
 1314                  */
 1315                 ncl_downgrade_vnlock(vp, old_lock);
 1316                 return (0);
 1317         }
 1318 
 1319         /*
 1320          * Now, flush as required.
 1321          */
 1322         if ((flags & V_SAVE) && (vp->v_bufobj.bo_object != NULL)) {
 1323                 VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
 1324                 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
 1325                 VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
 1326                 /*
 1327                  * If the page clean was interrupted, fail the invalidation.
 1328                  * Not doing so, we run the risk of losing dirty pages in the 
 1329                  * vinvalbuf() call below.
 1330                  */
 1331                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1332                         goto out;
 1333         }
 1334 
 1335         error = vinvalbuf(vp, flags, slpflag, 0);
 1336         while (error) {
 1337                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1338                         goto out;
 1339                 error = vinvalbuf(vp, flags, 0, slptimeo);
 1340         }
 1341         mtx_lock(&np->n_mtx);
 1342         if (np->n_directio_asyncwr == 0)
 1343                 np->n_flag &= ~NMODIFIED;
 1344         mtx_unlock(&np->n_mtx);
 1345 out:
 1346         ncl_downgrade_vnlock(vp, old_lock);
 1347         return error;
 1348 }
 1349 
 1350 /*
 1351  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
 1352  * This is mainly to avoid queueing async I/O requests when the nfsiods
 1353  * are all hung on a dead server.
 1354  *
 1355  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
 1356  * is eventually dequeued by the async daemon, ncl_doio() *will*.
 1357  */
 1358 int
 1359 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
 1360 {
 1361         int iod;
 1362         int gotiod;
 1363         int slpflag = 0;
 1364         int slptimeo = 0;
 1365         int error, error2;
 1366 
 1367         /*
 1368          * Commits are usually short and sweet so lets save some cpu and
 1369          * leave the async daemons for more important rpc's (such as reads
 1370          * and writes).
 1371          *
 1372          * Readdirplus RPCs do vget()s to acquire the vnodes for entries
 1373          * in the directory in order to update attributes. This can deadlock
 1374          * with another thread that is waiting for async I/O to be done by
 1375          * an nfsiod thread while holding a lock on one of these vnodes.
 1376          * To avoid this deadlock, don't allow the async nfsiod threads to
 1377          * perform Readdirplus RPCs.
 1378          */
 1379         mtx_lock(&ncl_iod_mutex);
 1380         if ((bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
 1381              (nmp->nm_bufqiods > ncl_numasync / 2)) ||
 1382             (bp->b_vp->v_type == VDIR && (nmp->nm_flag & NFSMNT_RDIRPLUS))) {
 1383                 mtx_unlock(&ncl_iod_mutex);
 1384                 return(EIO);
 1385         }
 1386 again:
 1387         if (nmp->nm_flag & NFSMNT_INT)
 1388                 slpflag = NFS_PCATCH;
 1389         gotiod = FALSE;
 1390 
 1391         /*
 1392          * Find a free iod to process this request.
 1393          */
 1394         for (iod = 0; iod < ncl_numasync; iod++)
 1395                 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
 1396                         gotiod = TRUE;
 1397                         break;
 1398                 }
 1399 
 1400         /*
 1401          * Try to create one if none are free.
 1402          */
 1403         if (!gotiod)
 1404                 ncl_nfsiodnew();
 1405         else {
 1406                 /*
 1407                  * Found one, so wake it up and tell it which
 1408                  * mount to process.
 1409                  */
 1410                 NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
 1411                     iod, nmp));
 1412                 ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
 1413                 ncl_iodmount[iod] = nmp;
 1414                 nmp->nm_bufqiods++;
 1415                 wakeup(&ncl_iodwant[iod]);
 1416         }
 1417 
 1418         /*
 1419          * If none are free, we may already have an iod working on this mount
 1420          * point.  If so, it will process our request.
 1421          */
 1422         if (!gotiod) {
 1423                 if (nmp->nm_bufqiods > 0) {
 1424                         NFS_DPF(ASYNCIO,
 1425                                 ("ncl_asyncio: %d iods are already processing mount %p\n",
 1426                                  nmp->nm_bufqiods, nmp));
 1427                         gotiod = TRUE;
 1428                 }
 1429         }
 1430 
 1431         /*
 1432          * If we have an iod which can process the request, then queue
 1433          * the buffer.
 1434          */
 1435         if (gotiod) {
 1436                 /*
 1437                  * Ensure that the queue never grows too large.  We still want
 1438                  * to asynchronize so we block rather then return EIO.
 1439                  */
 1440                 while (nmp->nm_bufqlen >= 2*ncl_numasync) {
 1441                         NFS_DPF(ASYNCIO,
 1442                                 ("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
 1443                         nmp->nm_bufqwant = TRUE;
 1444                         error = newnfs_msleep(td, &nmp->nm_bufq, 
 1445                             &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
 1446                            slptimeo);
 1447                         if (error) {
 1448                                 error2 = newnfs_sigintr(nmp, td);
 1449                                 if (error2) {
 1450                                         mtx_unlock(&ncl_iod_mutex);                                     
 1451                                         return (error2);
 1452                                 }
 1453                                 if (slpflag == NFS_PCATCH) {
 1454                                         slpflag = 0;
 1455                                         slptimeo = 2 * hz;
 1456                                 }
 1457                         }
 1458                         /*
 1459                          * We might have lost our iod while sleeping,
 1460                          * so check and loop if nescessary.
 1461                          */
 1462                         goto again;
 1463                 }
 1464 
 1465                 /* We might have lost our nfsiod */
 1466                 if (nmp->nm_bufqiods == 0) {
 1467                         NFS_DPF(ASYNCIO,
 1468                                 ("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
 1469                         goto again;
 1470                 }
 1471 
 1472                 if (bp->b_iocmd == BIO_READ) {
 1473                         if (bp->b_rcred == NOCRED && cred != NOCRED)
 1474                                 bp->b_rcred = crhold(cred);
 1475                 } else {
 1476                         if (bp->b_wcred == NOCRED && cred != NOCRED)
 1477                                 bp->b_wcred = crhold(cred);
 1478                 }
 1479 
 1480                 if (bp->b_flags & B_REMFREE)
 1481                         bremfreef(bp);
 1482                 BUF_KERNPROC(bp);
 1483                 TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
 1484                 nmp->nm_bufqlen++;
 1485                 if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1486                         mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);                   
 1487                         VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
 1488                         VTONFS(bp->b_vp)->n_directio_asyncwr++;
 1489                         mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
 1490                 }
 1491                 mtx_unlock(&ncl_iod_mutex);
 1492                 return (0);
 1493         }
 1494 
 1495         mtx_unlock(&ncl_iod_mutex);
 1496 
 1497         /*
 1498          * All the iods are busy on other mounts, so return EIO to
 1499          * force the caller to process the i/o synchronously.
 1500          */
 1501         NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
 1502         return (EIO);
 1503 }
 1504 
 1505 void
 1506 ncl_doio_directwrite(struct buf *bp)
 1507 {
 1508         int iomode, must_commit;
 1509         struct uio *uiop = (struct uio *)bp->b_caller1;
 1510         char *iov_base = uiop->uio_iov->iov_base;
 1511         
 1512         iomode = NFSWRITE_FILESYNC;
 1513         uiop->uio_td = NULL; /* NULL since we're in nfsiod */
 1514         ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
 1515         KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
 1516         free(iov_base, M_NFSDIRECTIO);
 1517         free(uiop->uio_iov, M_NFSDIRECTIO);
 1518         free(uiop, M_NFSDIRECTIO);
 1519         if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1520                 struct nfsnode *np = VTONFS(bp->b_vp);
 1521                 mtx_lock(&np->n_mtx);
 1522                 np->n_directio_asyncwr--;
 1523                 if (np->n_directio_asyncwr == 0) {
 1524                         np->n_flag &= ~NMODIFIED;
 1525                         if ((np->n_flag & NFSYNCWAIT)) {
 1526                                 np->n_flag &= ~NFSYNCWAIT;
 1527                                 wakeup((caddr_t)&np->n_directio_asyncwr);
 1528                         }
 1529                 }
 1530                 mtx_unlock(&np->n_mtx);
 1531         }
 1532         bp->b_vp = NULL;
 1533         relpbuf(bp, &ncl_pbuf_freecnt);
 1534 }
 1535 
 1536 /*
 1537  * Do an I/O operation to/from a cache block. This may be called
 1538  * synchronously or from an nfsiod.
 1539  */
 1540 int
 1541 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
 1542     int called_from_strategy)
 1543 {
 1544         struct uio *uiop;
 1545         struct nfsnode *np;
 1546         struct nfsmount *nmp;
 1547         int error = 0, iomode, must_commit = 0;
 1548         struct uio uio;
 1549         struct iovec io;
 1550         struct proc *p = td ? td->td_proc : NULL;
 1551         uint8_t iocmd;
 1552         
 1553         np = VTONFS(vp);
 1554         nmp = VFSTONFS(vp->v_mount);
 1555         uiop = &uio;
 1556         uiop->uio_iov = &io;
 1557         uiop->uio_iovcnt = 1;
 1558         uiop->uio_segflg = UIO_SYSSPACE;
 1559         uiop->uio_td = td;
 1560 
 1561         /*
 1562          * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
 1563          * do this here so we do not have to do it in all the code that
 1564          * calls us.
 1565          */
 1566         bp->b_flags &= ~B_INVAL;
 1567         bp->b_ioflags &= ~BIO_ERROR;
 1568 
 1569         KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
 1570         iocmd = bp->b_iocmd;
 1571         if (iocmd == BIO_READ) {
 1572             io.iov_len = uiop->uio_resid = bp->b_bcount;
 1573             io.iov_base = bp->b_data;
 1574             uiop->uio_rw = UIO_READ;
 1575 
 1576             switch (vp->v_type) {
 1577             case VREG:
 1578                 uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
 1579                 NFSINCRGLOBAL(newnfsstats.read_bios);
 1580                 error = ncl_readrpc(vp, uiop, cr);
 1581 
 1582                 if (!error) {
 1583                     if (uiop->uio_resid) {
 1584                         /*
 1585                          * If we had a short read with no error, we must have
 1586                          * hit a file hole.  We should zero-fill the remainder.
 1587                          * This can also occur if the server hits the file EOF.
 1588                          *
 1589                          * Holes used to be able to occur due to pending
 1590                          * writes, but that is not possible any longer.
 1591                          */
 1592                         int nread = bp->b_bcount - uiop->uio_resid;
 1593                         int left  = uiop->uio_resid;
 1594 
 1595                         if (left > 0)
 1596                                 bzero((char *)bp->b_data + nread, left);
 1597                         uiop->uio_resid = 0;
 1598                     }
 1599                 }
 1600                 /* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
 1601                 if (p && (vp->v_vflag & VV_TEXT)) {
 1602                         mtx_lock(&np->n_mtx);
 1603                         if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
 1604                                 mtx_unlock(&np->n_mtx);
 1605                                 PROC_LOCK(p);
 1606                                 killproc(p, "text file modification");
 1607                                 PROC_UNLOCK(p);
 1608                         } else
 1609                                 mtx_unlock(&np->n_mtx);
 1610                 }
 1611                 break;
 1612             case VLNK:
 1613                 uiop->uio_offset = (off_t)0;
 1614                 NFSINCRGLOBAL(newnfsstats.readlink_bios);
 1615                 error = ncl_readlinkrpc(vp, uiop, cr);
 1616                 break;
 1617             case VDIR:
 1618                 NFSINCRGLOBAL(newnfsstats.readdir_bios);
 1619                 uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
 1620                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
 1621                         error = ncl_readdirplusrpc(vp, uiop, cr, td);
 1622                         if (error == NFSERR_NOTSUPP)
 1623                                 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
 1624                 }
 1625                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
 1626                         error = ncl_readdirrpc(vp, uiop, cr, td);
 1627                 /*
 1628                  * end-of-directory sets B_INVAL but does not generate an
 1629                  * error.
 1630                  */
 1631                 if (error == 0 && uiop->uio_resid == bp->b_bcount)
 1632                         bp->b_flags |= B_INVAL;
 1633                 break;
 1634             default:
 1635                 ncl_printf("ncl_doio:  type %x unexpected\n", vp->v_type);
 1636                 break;
 1637             };
 1638             if (error) {
 1639                 bp->b_ioflags |= BIO_ERROR;
 1640                 bp->b_error = error;
 1641             }
 1642         } else {
 1643             /*
 1644              * If we only need to commit, try to commit
 1645              */
 1646             if (bp->b_flags & B_NEEDCOMMIT) {
 1647                     int retv;
 1648                     off_t off;
 1649 
 1650                     off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
 1651                     retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
 1652                         bp->b_wcred, td);
 1653                     if (retv == 0) {
 1654                             bp->b_dirtyoff = bp->b_dirtyend = 0;
 1655                             bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1656                             bp->b_resid = 0;
 1657                             bufdone(bp);
 1658                             return (0);
 1659                     }
 1660                     if (retv == NFSERR_STALEWRITEVERF) {
 1661                             ncl_clearcommit(vp->v_mount);
 1662                     }
 1663             }
 1664 
 1665             /*
 1666              * Setup for actual write
 1667              */
 1668             mtx_lock(&np->n_mtx);
 1669             if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
 1670                 bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
 1671             mtx_unlock(&np->n_mtx);
 1672 
 1673             if (bp->b_dirtyend > bp->b_dirtyoff) {
 1674                 io.iov_len = uiop->uio_resid = bp->b_dirtyend
 1675                     - bp->b_dirtyoff;
 1676                 uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
 1677                     + bp->b_dirtyoff;
 1678                 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
 1679                 uiop->uio_rw = UIO_WRITE;
 1680                 NFSINCRGLOBAL(newnfsstats.write_bios);
 1681 
 1682                 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
 1683                     iomode = NFSWRITE_UNSTABLE;
 1684                 else
 1685                     iomode = NFSWRITE_FILESYNC;
 1686 
 1687                 error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
 1688                     called_from_strategy);
 1689 
 1690                 /*
 1691                  * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
 1692                  * to cluster the buffers needing commit.  This will allow
 1693                  * the system to submit a single commit rpc for the whole
 1694                  * cluster.  We can do this even if the buffer is not 100%
 1695                  * dirty (relative to the NFS blocksize), so we optimize the
 1696                  * append-to-file-case.
 1697                  *
 1698                  * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
 1699                  * cleared because write clustering only works for commit
 1700                  * rpc's, not for the data portion of the write).
 1701                  */
 1702 
 1703                 if (!error && iomode == NFSWRITE_UNSTABLE) {
 1704                     bp->b_flags |= B_NEEDCOMMIT;
 1705                     if (bp->b_dirtyoff == 0
 1706                         && bp->b_dirtyend == bp->b_bcount)
 1707                         bp->b_flags |= B_CLUSTEROK;
 1708                 } else {
 1709                     bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1710                 }
 1711 
 1712                 /*
 1713                  * For an interrupted write, the buffer is still valid
 1714                  * and the write hasn't been pushed to the server yet,
 1715                  * so we can't set BIO_ERROR and report the interruption
 1716                  * by setting B_EINTR. For the B_ASYNC case, B_EINTR
 1717                  * is not relevant, so the rpc attempt is essentially
 1718                  * a noop.  For the case of a V3 write rpc not being
 1719                  * committed to stable storage, the block is still
 1720                  * dirty and requires either a commit rpc or another
 1721                  * write rpc with iomode == NFSV3WRITE_FILESYNC before
 1722                  * the block is reused. This is indicated by setting
 1723                  * the B_DELWRI and B_NEEDCOMMIT flags.
 1724                  *
 1725                  * EIO is returned by ncl_writerpc() to indicate a recoverable
 1726                  * write error and is handled as above, except that
 1727                  * B_EINTR isn't set. One cause of this is a stale stateid
 1728                  * error for the RPC that indicates recovery is required,
 1729                  * when called with called_from_strategy != 0.
 1730                  *
 1731                  * If the buffer is marked B_PAGING, it does not reside on
 1732                  * the vp's paging queues so we cannot call bdirty().  The
 1733                  * bp in this case is not an NFS cache block so we should
 1734                  * be safe. XXX
 1735                  *
 1736                  * The logic below breaks up errors into recoverable and 
 1737                  * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
 1738                  * and keep the buffer around for potential write retries.
 1739                  * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
 1740                  * and save the error in the nfsnode. This is less than ideal 
 1741                  * but necessary. Keeping such buffers around could potentially
 1742                  * cause buffer exhaustion eventually (they can never be written
 1743                  * out, so will get constantly be re-dirtied). It also causes
 1744                  * all sorts of vfs panics. For non-recoverable write errors, 
 1745                  * also invalidate the attrcache, so we'll be forced to go over
 1746                  * the wire for this object, returning an error to user on next
 1747                  * call (most of the time).
 1748                  */
 1749                 if (error == EINTR || error == EIO || error == ETIMEDOUT
 1750                     || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
 1751                         int s;
 1752 
 1753                         s = splbio();
 1754                         bp->b_flags &= ~(B_INVAL|B_NOCACHE);
 1755                         if ((bp->b_flags & B_PAGING) == 0) {
 1756                             bdirty(bp);
 1757                             bp->b_flags &= ~B_DONE;
 1758                         }
 1759                         if ((error == EINTR || error == ETIMEDOUT) &&
 1760                             (bp->b_flags & B_ASYNC) == 0)
 1761                             bp->b_flags |= B_EINTR;
 1762                         splx(s);
 1763                 } else {
 1764                     if (error) {
 1765                         bp->b_ioflags |= BIO_ERROR;
 1766                         bp->b_flags |= B_INVAL;
 1767                         bp->b_error = np->n_error = error;
 1768                         mtx_lock(&np->n_mtx);
 1769                         np->n_flag |= NWRITEERR;
 1770                         np->n_attrstamp = 0;
 1771                         mtx_unlock(&np->n_mtx);
 1772                     }
 1773                     bp->b_dirtyoff = bp->b_dirtyend = 0;
 1774                 }
 1775             } else {
 1776                 bp->b_resid = 0;
 1777                 bufdone(bp);
 1778                 return (0);
 1779             }
 1780         }
 1781         bp->b_resid = uiop->uio_resid;
 1782         if (must_commit)
 1783             ncl_clearcommit(vp->v_mount);
 1784         bufdone(bp);
 1785         return (error);
 1786 }
 1787 
 1788 /*
 1789  * Used to aid in handling ftruncate() operations on the NFS client side.
 1790  * Truncation creates a number of special problems for NFS.  We have to
 1791  * throw away VM pages and buffer cache buffers that are beyond EOF, and
 1792  * we have to properly handle VM pages or (potentially dirty) buffers
 1793  * that straddle the truncation point.
 1794  */
 1795 
 1796 int
 1797 ncl_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
 1798 {
 1799         struct nfsnode *np = VTONFS(vp);
 1800         u_quad_t tsize;
 1801         int biosize = vp->v_bufobj.bo_bsize;
 1802         int error = 0;
 1803 
 1804         mtx_lock(&np->n_mtx);
 1805         tsize = np->n_size;
 1806         np->n_size = nsize;
 1807         mtx_unlock(&np->n_mtx);
 1808 
 1809         if (nsize < tsize) {
 1810                 struct buf *bp;
 1811                 daddr_t lbn;
 1812                 int bufsize;
 1813 
 1814                 /*
 1815                  * vtruncbuf() doesn't get the buffer overlapping the 
 1816                  * truncation point.  We may have a B_DELWRI and/or B_CACHE
 1817                  * buffer that now needs to be truncated.
 1818                  */
 1819                 error = vtruncbuf(vp, cred, td, nsize, biosize);
 1820                 lbn = nsize / biosize;
 1821                 bufsize = nsize & (biosize - 1);
 1822                 bp = nfs_getcacheblk(vp, lbn, bufsize, td);
 1823                 if (!bp)
 1824                         return EINTR;
 1825                 if (bp->b_dirtyoff > bp->b_bcount)
 1826                         bp->b_dirtyoff = bp->b_bcount;
 1827                 if (bp->b_dirtyend > bp->b_bcount)
 1828                         bp->b_dirtyend = bp->b_bcount;
 1829                 bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
 1830                 brelse(bp);
 1831         } else {
 1832                 vnode_pager_setsize(vp, nsize);
 1833         }
 1834         return(error);
 1835 }
 1836 

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