The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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/11/sys/fs/nfsclient/nfs_clbio.c 349308 2019-06-23 14:49:30Z asomers $");
   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/rwlock.h>
   45 #include <sys/vmmeter.h>
   46 #include <sys/vnode.h>
   47 
   48 #include <vm/vm.h>
   49 #include <vm/vm_param.h>
   50 #include <vm/vm_extern.h>
   51 #include <vm/vm_page.h>
   52 #include <vm/vm_object.h>
   53 #include <vm/vm_pager.h>
   54 #include <vm/vnode_pager.h>
   55 
   56 #include <fs/nfs/nfsport.h>
   57 #include <fs/nfsclient/nfsmount.h>
   58 #include <fs/nfsclient/nfs.h>
   59 #include <fs/nfsclient/nfsnode.h>
   60 #include <fs/nfsclient/nfs_kdtrace.h>
   61 
   62 extern int newnfs_directio_allow_mmap;
   63 extern struct nfsstatsv1 nfsstatsv1;
   64 extern struct mtx ncl_iod_mutex;
   65 extern int ncl_numasync;
   66 extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
   67 extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
   68 extern int newnfs_directio_enable;
   69 extern int nfs_keep_dirty_on_error;
   70 
   71 int ncl_pbuf_freecnt = -1;      /* start out unlimited */
   72 
   73 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
   74     struct thread *td);
   75 static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
   76     struct ucred *cred, int ioflag);
   77 
   78 /*
   79  * Vnode op for VM getpages.
   80  */
   81 SYSCTL_DECL(_vfs_nfs);
   82 static int use_buf_pager = 0;
   83 SYSCTL_INT(_vfs_nfs, OID_AUTO, use_buf_pager, CTLFLAG_RWTUN,
   84     &use_buf_pager, 0,
   85     "Use buffer pager instead of direct readrpc call");
   86 
   87 static daddr_t
   88 ncl_gbp_getblkno(struct vnode *vp, vm_ooffset_t off)
   89 {
   90 
   91         return (off / vp->v_bufobj.bo_bsize);
   92 }
   93 
   94 static int
   95 ncl_gbp_getblksz(struct vnode *vp, daddr_t lbn)
   96 {
   97         struct nfsnode *np;
   98         u_quad_t nsize;
   99         int biosize, bcount;
  100 
  101         np = VTONFS(vp);
  102         mtx_lock(&np->n_mtx);
  103         nsize = np->n_size;
  104         mtx_unlock(&np->n_mtx);
  105 
  106         biosize = vp->v_bufobj.bo_bsize;
  107         bcount = biosize;
  108         if ((off_t)lbn * biosize >= nsize)
  109                 bcount = 0;
  110         else if ((off_t)(lbn + 1) * biosize > nsize)
  111                 bcount = nsize - (off_t)lbn * biosize;
  112         return (bcount);
  113 }
  114 
  115 int
  116 ncl_getpages(struct vop_getpages_args *ap)
  117 {
  118         int i, error, nextoff, size, toff, count, npages;
  119         struct uio uio;
  120         struct iovec iov;
  121         vm_offset_t kva;
  122         struct buf *bp;
  123         struct vnode *vp;
  124         struct thread *td;
  125         struct ucred *cred;
  126         struct nfsmount *nmp;
  127         vm_object_t object;
  128         vm_page_t *pages;
  129         struct nfsnode *np;
  130 
  131         vp = ap->a_vp;
  132         np = VTONFS(vp);
  133         td = curthread;
  134         cred = curthread->td_ucred;
  135         nmp = VFSTONFS(vp->v_mount);
  136         pages = ap->a_m;
  137         npages = ap->a_count;
  138 
  139         if ((object = vp->v_object) == NULL) {
  140                 printf("ncl_getpages: called with non-merged cache vnode\n");
  141                 return (VM_PAGER_ERROR);
  142         }
  143 
  144         if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
  145                 mtx_lock(&np->n_mtx);
  146                 if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  147                         mtx_unlock(&np->n_mtx);
  148                         printf("ncl_getpages: called on non-cacheable vnode\n");
  149                         return (VM_PAGER_ERROR);
  150                 } else
  151                         mtx_unlock(&np->n_mtx);
  152         }
  153 
  154         mtx_lock(&nmp->nm_mtx);
  155         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  156             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  157                 mtx_unlock(&nmp->nm_mtx);
  158                 /* We'll never get here for v4, because we always have fsinfo */
  159                 (void)ncl_fsinfo(nmp, vp, cred, td);
  160         } else
  161                 mtx_unlock(&nmp->nm_mtx);
  162 
  163         if (use_buf_pager)
  164                 return (vfs_bio_getpages(vp, pages, npages, ap->a_rbehind,
  165                     ap->a_rahead, ncl_gbp_getblkno, ncl_gbp_getblksz));
  166 
  167         /*
  168          * If the requested page is partially valid, just return it and
  169          * allow the pager to zero-out the blanks.  Partially valid pages
  170          * can only occur at the file EOF.
  171          *
  172          * XXXGL: is that true for NFS, where short read can occur???
  173          */
  174         VM_OBJECT_WLOCK(object);
  175         if (pages[npages - 1]->valid != 0 && --npages == 0)
  176                 goto out;
  177         VM_OBJECT_WUNLOCK(object);
  178 
  179         /*
  180          * We use only the kva address for the buffer, but this is extremely
  181          * convenient and fast.
  182          */
  183         bp = getpbuf(&ncl_pbuf_freecnt);
  184 
  185         kva = (vm_offset_t) bp->b_data;
  186         pmap_qenter(kva, pages, npages);
  187         PCPU_INC(cnt.v_vnodein);
  188         PCPU_ADD(cnt.v_vnodepgsin, npages);
  189 
  190         count = npages << PAGE_SHIFT;
  191         iov.iov_base = (caddr_t) kva;
  192         iov.iov_len = count;
  193         uio.uio_iov = &iov;
  194         uio.uio_iovcnt = 1;
  195         uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
  196         uio.uio_resid = count;
  197         uio.uio_segflg = UIO_SYSSPACE;
  198         uio.uio_rw = UIO_READ;
  199         uio.uio_td = td;
  200 
  201         error = ncl_readrpc(vp, &uio, cred);
  202         pmap_qremove(kva, npages);
  203 
  204         relpbuf(bp, &ncl_pbuf_freecnt);
  205 
  206         if (error && (uio.uio_resid == count)) {
  207                 printf("ncl_getpages: error %d\n", error);
  208                 return (VM_PAGER_ERROR);
  209         }
  210 
  211         /*
  212          * Calculate the number of bytes read and validate only that number
  213          * of bytes.  Note that due to pending writes, size may be 0.  This
  214          * does not mean that the remaining data is invalid!
  215          */
  216 
  217         size = count - uio.uio_resid;
  218         VM_OBJECT_WLOCK(object);
  219         for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
  220                 vm_page_t m;
  221                 nextoff = toff + PAGE_SIZE;
  222                 m = pages[i];
  223 
  224                 if (nextoff <= size) {
  225                         /*
  226                          * Read operation filled an entire page
  227                          */
  228                         m->valid = VM_PAGE_BITS_ALL;
  229                         KASSERT(m->dirty == 0,
  230                             ("nfs_getpages: page %p is dirty", m));
  231                 } else if (size > toff) {
  232                         /*
  233                          * Read operation filled a partial page.
  234                          */
  235                         m->valid = 0;
  236                         vm_page_set_valid_range(m, 0, size - toff);
  237                         KASSERT(m->dirty == 0,
  238                             ("nfs_getpages: page %p is dirty", m));
  239                 } else {
  240                         /*
  241                          * Read operation was short.  If no error
  242                          * occurred we may have hit a zero-fill
  243                          * section.  We leave valid set to 0, and page
  244                          * is freed by vm_page_readahead_finish() if
  245                          * its index is not equal to requested, or
  246                          * page is zeroed and set valid by
  247                          * vm_pager_get_pages() for requested page.
  248                          */
  249                         ;
  250                 }
  251         }
  252 out:
  253         VM_OBJECT_WUNLOCK(object);
  254         if (ap->a_rbehind)
  255                 *ap->a_rbehind = 0;
  256         if (ap->a_rahead)
  257                 *ap->a_rahead = 0;
  258         return (VM_PAGER_OK);
  259 }
  260 
  261 /*
  262  * Vnode op for VM putpages.
  263  */
  264 int
  265 ncl_putpages(struct vop_putpages_args *ap)
  266 {
  267         struct uio uio;
  268         struct iovec iov;
  269         int i, error, npages, count;
  270         off_t offset;
  271         int *rtvals;
  272         struct vnode *vp;
  273         struct thread *td;
  274         struct ucred *cred;
  275         struct nfsmount *nmp;
  276         struct nfsnode *np;
  277         vm_page_t *pages;
  278 
  279         vp = ap->a_vp;
  280         np = VTONFS(vp);
  281         td = curthread;                         /* XXX */
  282         /* Set the cred to n_writecred for the write rpcs. */
  283         if (np->n_writecred != NULL)
  284                 cred = crhold(np->n_writecred);
  285         else
  286                 cred = crhold(curthread->td_ucred);     /* XXX */
  287         nmp = VFSTONFS(vp->v_mount);
  288         pages = ap->a_m;
  289         count = ap->a_count;
  290         rtvals = ap->a_rtvals;
  291         npages = btoc(count);
  292         offset = IDX_TO_OFF(pages[0]->pindex);
  293 
  294         mtx_lock(&nmp->nm_mtx);
  295         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  296             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  297                 mtx_unlock(&nmp->nm_mtx);
  298                 (void)ncl_fsinfo(nmp, vp, cred, td);
  299         } else
  300                 mtx_unlock(&nmp->nm_mtx);
  301 
  302         mtx_lock(&np->n_mtx);
  303         if (newnfs_directio_enable && !newnfs_directio_allow_mmap &&
  304             (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  305                 mtx_unlock(&np->n_mtx);
  306                 printf("ncl_putpages: called on noncache-able vnode\n");
  307                 mtx_lock(&np->n_mtx);
  308         }
  309         /*
  310          * When putting pages, do not extend file past EOF.
  311          */
  312         if (offset + count > np->n_size) {
  313                 count = np->n_size - offset;
  314                 if (count < 0)
  315                         count = 0;
  316         }
  317         mtx_unlock(&np->n_mtx);
  318 
  319         for (i = 0; i < npages; i++)
  320                 rtvals[i] = VM_PAGER_ERROR;
  321 
  322         PCPU_INC(cnt.v_vnodeout);
  323         PCPU_ADD(cnt.v_vnodepgsout, count);
  324 
  325         iov.iov_base = unmapped_buf;
  326         iov.iov_len = count;
  327         uio.uio_iov = &iov;
  328         uio.uio_iovcnt = 1;
  329         uio.uio_offset = offset;
  330         uio.uio_resid = count;
  331         uio.uio_segflg = UIO_NOCOPY;
  332         uio.uio_rw = UIO_WRITE;
  333         uio.uio_td = td;
  334 
  335         error = VOP_WRITE(vp, &uio, vnode_pager_putpages_ioflags(ap->a_sync),
  336             cred);
  337         crfree(cred);
  338 
  339         if (error == 0 || !nfs_keep_dirty_on_error) {
  340                 vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid,
  341                     np->n_size - offset, npages * PAGE_SIZE);
  342         }
  343         return (rtvals[0]);
  344 }
  345 
  346 /*
  347  * For nfs, cache consistency can only be maintained approximately.
  348  * Although RFC1094 does not specify the criteria, the following is
  349  * believed to be compatible with the reference port.
  350  * For nfs:
  351  * If the file's modify time on the server has changed since the
  352  * last read rpc or you have written to the file,
  353  * you may have lost data cache consistency with the
  354  * server, so flush all of the file's data out of the cache.
  355  * Then force a getattr rpc to ensure that you have up to date
  356  * attributes.
  357  * NB: This implies that cache data can be read when up to
  358  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
  359  * attributes this could be forced by setting n_attrstamp to 0 before
  360  * the VOP_GETATTR() call.
  361  */
  362 static inline int
  363 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
  364 {
  365         int error = 0;
  366         struct vattr vattr;
  367         struct nfsnode *np = VTONFS(vp);
  368         bool old_lock;
  369 
  370         /*
  371          * Ensure the exclusove access to the node before checking
  372          * whether the cache is consistent.
  373          */
  374         old_lock = ncl_excl_start(vp);
  375         mtx_lock(&np->n_mtx);
  376         if (np->n_flag & NMODIFIED) {
  377                 mtx_unlock(&np->n_mtx);
  378                 if (vp->v_type != VREG) {
  379                         if (vp->v_type != VDIR)
  380                                 panic("nfs: bioread, not dir");
  381                         ncl_invaldir(vp);
  382                         error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
  383                         if (error != 0)
  384                                 goto out;
  385                 }
  386                 np->n_attrstamp = 0;
  387                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  388                 error = VOP_GETATTR(vp, &vattr, cred);
  389                 if (error)
  390                         goto out;
  391                 mtx_lock(&np->n_mtx);
  392                 np->n_mtime = vattr.va_mtime;
  393                 mtx_unlock(&np->n_mtx);
  394         } else {
  395                 mtx_unlock(&np->n_mtx);
  396                 error = VOP_GETATTR(vp, &vattr, cred);
  397                 if (error)
  398                         goto out;
  399                 mtx_lock(&np->n_mtx);
  400                 if ((np->n_flag & NSIZECHANGED)
  401                     || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
  402                         mtx_unlock(&np->n_mtx);
  403                         if (vp->v_type == VDIR)
  404                                 ncl_invaldir(vp);
  405                         error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
  406                         if (error != 0)
  407                                 goto out;
  408                         mtx_lock(&np->n_mtx);
  409                         np->n_mtime = vattr.va_mtime;
  410                         np->n_flag &= ~NSIZECHANGED;
  411                 }
  412                 mtx_unlock(&np->n_mtx);
  413         }
  414 out:
  415         ncl_excl_finish(vp, old_lock);
  416         return (error);
  417 }
  418 
  419 /*
  420  * Vnode op for read using bio
  421  */
  422 int
  423 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
  424 {
  425         struct nfsnode *np = VTONFS(vp);
  426         int biosize, i;
  427         struct buf *bp, *rabp;
  428         struct thread *td;
  429         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  430         daddr_t lbn, rabn;
  431         int bcount;
  432         int seqcount;
  433         int nra, error = 0, n = 0, on = 0;
  434         off_t tmp_off;
  435 
  436         KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
  437         if (uio->uio_resid == 0)
  438                 return (0);
  439         if (uio->uio_offset < 0)        /* XXX VDIR cookies can be negative */
  440                 return (EINVAL);
  441         td = uio->uio_td;
  442 
  443         mtx_lock(&nmp->nm_mtx);
  444         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  445             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  446                 mtx_unlock(&nmp->nm_mtx);
  447                 (void)ncl_fsinfo(nmp, vp, cred, td);
  448                 mtx_lock(&nmp->nm_mtx);
  449         }
  450         if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
  451                 (void) newnfs_iosize(nmp);
  452 
  453         tmp_off = uio->uio_offset + uio->uio_resid;
  454         if (vp->v_type != VDIR &&
  455             (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)) {
  456                 mtx_unlock(&nmp->nm_mtx);
  457                 return (EFBIG);
  458         }
  459         mtx_unlock(&nmp->nm_mtx);
  460 
  461         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
  462                 /* No caching/ no readaheads. Just read data into the user buffer */
  463                 return ncl_readrpc(vp, uio, cred);
  464 
  465         biosize = vp->v_bufobj.bo_bsize;
  466         seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
  467 
  468         error = nfs_bioread_check_cons(vp, td, cred);
  469         if (error)
  470                 return error;
  471 
  472         do {
  473             u_quad_t nsize;
  474 
  475             mtx_lock(&np->n_mtx);
  476             nsize = np->n_size;
  477             mtx_unlock(&np->n_mtx);
  478 
  479             switch (vp->v_type) {
  480             case VREG:
  481                 NFSINCRGLOBAL(nfsstatsv1.biocache_reads);
  482                 lbn = uio->uio_offset / biosize;
  483                 on = uio->uio_offset - (lbn * biosize);
  484 
  485                 /*
  486                  * Start the read ahead(s), as required.
  487                  */
  488                 if (nmp->nm_readahead > 0) {
  489                     for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
  490                         (off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
  491                         rabn = lbn + 1 + nra;
  492                         if (incore(&vp->v_bufobj, rabn) == NULL) {
  493                             rabp = nfs_getcacheblk(vp, rabn, biosize, td);
  494                             if (!rabp) {
  495                                 error = newnfs_sigintr(nmp, td);
  496                                 return (error ? error : EINTR);
  497                             }
  498                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  499                                 rabp->b_flags |= B_ASYNC;
  500                                 rabp->b_iocmd = BIO_READ;
  501                                 vfs_busy_pages(rabp, 0);
  502                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  503                                     rabp->b_flags |= B_INVAL;
  504                                     rabp->b_ioflags |= BIO_ERROR;
  505                                     vfs_unbusy_pages(rabp);
  506                                     brelse(rabp);
  507                                     break;
  508                                 }
  509                             } else {
  510                                 brelse(rabp);
  511                             }
  512                         }
  513                     }
  514                 }
  515 
  516                 /* Note that bcount is *not* DEV_BSIZE aligned. */
  517                 bcount = biosize;
  518                 if ((off_t)lbn * biosize >= nsize) {
  519                         bcount = 0;
  520                 } else if ((off_t)(lbn + 1) * biosize > nsize) {
  521                         bcount = nsize - (off_t)lbn * biosize;
  522                 }
  523                 bp = nfs_getcacheblk(vp, lbn, bcount, td);
  524 
  525                 if (!bp) {
  526                         error = newnfs_sigintr(nmp, td);
  527                         return (error ? error : EINTR);
  528                 }
  529 
  530                 /*
  531                  * If B_CACHE is not set, we must issue the read.  If this
  532                  * fails, we return an error.
  533                  */
  534 
  535                 if ((bp->b_flags & B_CACHE) == 0) {
  536                     bp->b_iocmd = BIO_READ;
  537                     vfs_busy_pages(bp, 0);
  538                     error = ncl_doio(vp, bp, cred, td, 0);
  539                     if (error) {
  540                         brelse(bp);
  541                         return (error);
  542                     }
  543                 }
  544 
  545                 /*
  546                  * on is the offset into the current bp.  Figure out how many
  547                  * bytes we can copy out of the bp.  Note that bcount is
  548                  * NOT DEV_BSIZE aligned.
  549                  *
  550                  * Then figure out how many bytes we can copy into the uio.
  551                  */
  552 
  553                 n = 0;
  554                 if (on < bcount)
  555                         n = MIN((unsigned)(bcount - on), uio->uio_resid);
  556                 break;
  557             case VLNK:
  558                 NFSINCRGLOBAL(nfsstatsv1.biocache_readlinks);
  559                 bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
  560                 if (!bp) {
  561                         error = newnfs_sigintr(nmp, td);
  562                         return (error ? error : EINTR);
  563                 }
  564                 if ((bp->b_flags & B_CACHE) == 0) {
  565                     bp->b_iocmd = BIO_READ;
  566                     vfs_busy_pages(bp, 0);
  567                     error = ncl_doio(vp, bp, cred, td, 0);
  568                     if (error) {
  569                         bp->b_ioflags |= BIO_ERROR;
  570                         brelse(bp);
  571                         return (error);
  572                     }
  573                 }
  574                 n = MIN(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
  575                 on = 0;
  576                 break;
  577             case VDIR:
  578                 NFSINCRGLOBAL(nfsstatsv1.biocache_readdirs);
  579                 if (np->n_direofoffset
  580                     && uio->uio_offset >= np->n_direofoffset) {
  581                     return (0);
  582                 }
  583                 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
  584                 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
  585                 bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
  586                 if (!bp) {
  587                     error = newnfs_sigintr(nmp, td);
  588                     return (error ? error : EINTR);
  589                 }
  590                 if ((bp->b_flags & B_CACHE) == 0) {
  591                     bp->b_iocmd = BIO_READ;
  592                     vfs_busy_pages(bp, 0);
  593                     error = ncl_doio(vp, bp, cred, td, 0);
  594                     if (error) {
  595                             brelse(bp);
  596                     }
  597                     while (error == NFSERR_BAD_COOKIE) {
  598                         ncl_invaldir(vp);
  599                         error = ncl_vinvalbuf(vp, 0, td, 1);
  600 
  601                         /*
  602                          * Yuck! The directory has been modified on the
  603                          * server. The only way to get the block is by
  604                          * reading from the beginning to get all the
  605                          * offset cookies.
  606                          *
  607                          * Leave the last bp intact unless there is an error.
  608                          * Loop back up to the while if the error is another
  609                          * NFSERR_BAD_COOKIE (double yuch!).
  610                          */
  611                         for (i = 0; i <= lbn && !error; i++) {
  612                             if (np->n_direofoffset
  613                                 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
  614                                     return (0);
  615                             bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
  616                             if (!bp) {
  617                                 error = newnfs_sigintr(nmp, td);
  618                                 return (error ? error : EINTR);
  619                             }
  620                             if ((bp->b_flags & B_CACHE) == 0) {
  621                                     bp->b_iocmd = BIO_READ;
  622                                     vfs_busy_pages(bp, 0);
  623                                     error = ncl_doio(vp, bp, cred, td, 0);
  624                                     /*
  625                                      * no error + B_INVAL == directory EOF,
  626                                      * use the block.
  627                                      */
  628                                     if (error == 0 && (bp->b_flags & B_INVAL))
  629                                             break;
  630                             }
  631                             /*
  632                              * An error will throw away the block and the
  633                              * for loop will break out.  If no error and this
  634                              * is not the block we want, we throw away the
  635                              * block and go for the next one via the for loop.
  636                              */
  637                             if (error || i < lbn)
  638                                     brelse(bp);
  639                         }
  640                     }
  641                     /*
  642                      * The above while is repeated if we hit another cookie
  643                      * error.  If we hit an error and it wasn't a cookie error,
  644                      * we give up.
  645                      */
  646                     if (error)
  647                             return (error);
  648                 }
  649 
  650                 /*
  651                  * If not eof and read aheads are enabled, start one.
  652                  * (You need the current block first, so that you have the
  653                  *  directory offset cookie of the next block.)
  654                  */
  655                 if (nmp->nm_readahead > 0 &&
  656                     (bp->b_flags & B_INVAL) == 0 &&
  657                     (np->n_direofoffset == 0 ||
  658                     (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
  659                     incore(&vp->v_bufobj, lbn + 1) == NULL) {
  660                         rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
  661                         if (rabp) {
  662                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  663                                 rabp->b_flags |= B_ASYNC;
  664                                 rabp->b_iocmd = BIO_READ;
  665                                 vfs_busy_pages(rabp, 0);
  666                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  667                                     rabp->b_flags |= B_INVAL;
  668                                     rabp->b_ioflags |= BIO_ERROR;
  669                                     vfs_unbusy_pages(rabp);
  670                                     brelse(rabp);
  671                                 }
  672                             } else {
  673                                 brelse(rabp);
  674                             }
  675                         }
  676                 }
  677                 /*
  678                  * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
  679                  * chopped for the EOF condition, we cannot tell how large
  680                  * NFS directories are going to be until we hit EOF.  So
  681                  * an NFS directory buffer is *not* chopped to its EOF.  Now,
  682                  * it just so happens that b_resid will effectively chop it
  683                  * to EOF.  *BUT* this information is lost if the buffer goes
  684                  * away and is reconstituted into a B_CACHE state ( due to
  685                  * being VMIO ) later.  So we keep track of the directory eof
  686                  * in np->n_direofoffset and chop it off as an extra step
  687                  * right here.
  688                  */
  689                 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
  690                 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
  691                         n = np->n_direofoffset - uio->uio_offset;
  692                 break;
  693             default:
  694                 printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
  695                 bp = NULL;
  696                 break;
  697             }
  698 
  699             if (n > 0) {
  700                     error = vn_io_fault_uiomove(bp->b_data + on, (int)n, uio);
  701             }
  702             if (vp->v_type == VLNK)
  703                 n = 0;
  704             if (bp != NULL)
  705                 brelse(bp);
  706         } while (error == 0 && uio->uio_resid > 0 && n > 0);
  707         return (error);
  708 }
  709 
  710 /*
  711  * The NFS write path cannot handle iovecs with len > 1. So we need to
  712  * break up iovecs accordingly (restricting them to wsize).
  713  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
  714  * For the ASYNC case, 2 copies are needed. The first a copy from the
  715  * user buffer to a staging buffer and then a second copy from the staging
  716  * buffer to mbufs. This can be optimized by copying from the user buffer
  717  * directly into mbufs and passing the chain down, but that requires a
  718  * fair amount of re-working of the relevant codepaths (and can be done
  719  * later).
  720  */
  721 static int
  722 nfs_directio_write(vp, uiop, cred, ioflag)
  723         struct vnode *vp;
  724         struct uio *uiop;
  725         struct ucred *cred;
  726         int ioflag;
  727 {
  728         int error;
  729         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  730         struct thread *td = uiop->uio_td;
  731         int size;
  732         int wsize;
  733 
  734         mtx_lock(&nmp->nm_mtx);
  735         wsize = nmp->nm_wsize;
  736         mtx_unlock(&nmp->nm_mtx);
  737         if (ioflag & IO_SYNC) {
  738                 int iomode, must_commit;
  739                 struct uio uio;
  740                 struct iovec iov;
  741 do_sync:
  742                 while (uiop->uio_resid > 0) {
  743                         size = MIN(uiop->uio_resid, wsize);
  744                         size = MIN(uiop->uio_iov->iov_len, size);
  745                         iov.iov_base = uiop->uio_iov->iov_base;
  746                         iov.iov_len = size;
  747                         uio.uio_iov = &iov;
  748                         uio.uio_iovcnt = 1;
  749                         uio.uio_offset = uiop->uio_offset;
  750                         uio.uio_resid = size;
  751                         uio.uio_segflg = UIO_USERSPACE;
  752                         uio.uio_rw = UIO_WRITE;
  753                         uio.uio_td = td;
  754                         iomode = NFSWRITE_FILESYNC;
  755                         error = ncl_writerpc(vp, &uio, cred, &iomode,
  756                             &must_commit, 0);
  757                         KASSERT((must_commit == 0),
  758                                 ("ncl_directio_write: Did not commit write"));
  759                         if (error)
  760                                 return (error);
  761                         uiop->uio_offset += size;
  762                         uiop->uio_resid -= size;
  763                         if (uiop->uio_iov->iov_len <= size) {
  764                                 uiop->uio_iovcnt--;
  765                                 uiop->uio_iov++;
  766                         } else {
  767                                 uiop->uio_iov->iov_base =
  768                                         (char *)uiop->uio_iov->iov_base + size;
  769                                 uiop->uio_iov->iov_len -= size;
  770                         }
  771                 }
  772         } else {
  773                 struct uio *t_uio;
  774                 struct iovec *t_iov;
  775                 struct buf *bp;
  776 
  777                 /*
  778                  * Break up the write into blocksize chunks and hand these
  779                  * over to nfsiod's for write back.
  780                  * Unfortunately, this incurs a copy of the data. Since
  781                  * the user could modify the buffer before the write is
  782                  * initiated.
  783                  *
  784                  * The obvious optimization here is that one of the 2 copies
  785                  * in the async write path can be eliminated by copying the
  786                  * data here directly into mbufs and passing the mbuf chain
  787                  * down. But that will require a fair amount of re-working
  788                  * of the code and can be done if there's enough interest
  789                  * in NFS directio access.
  790                  */
  791                 while (uiop->uio_resid > 0) {
  792                         size = MIN(uiop->uio_resid, wsize);
  793                         size = MIN(uiop->uio_iov->iov_len, size);
  794                         bp = getpbuf(&ncl_pbuf_freecnt);
  795                         t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
  796                         t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
  797                         t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
  798                         t_iov->iov_len = size;
  799                         t_uio->uio_iov = t_iov;
  800                         t_uio->uio_iovcnt = 1;
  801                         t_uio->uio_offset = uiop->uio_offset;
  802                         t_uio->uio_resid = size;
  803                         t_uio->uio_segflg = UIO_SYSSPACE;
  804                         t_uio->uio_rw = UIO_WRITE;
  805                         t_uio->uio_td = td;
  806                         KASSERT(uiop->uio_segflg == UIO_USERSPACE ||
  807                             uiop->uio_segflg == UIO_SYSSPACE,
  808                             ("nfs_directio_write: Bad uio_segflg"));
  809                         if (uiop->uio_segflg == UIO_USERSPACE) {
  810                                 error = copyin(uiop->uio_iov->iov_base,
  811                                     t_iov->iov_base, size);
  812                                 if (error != 0)
  813                                         goto err_free;
  814                         } else
  815                                 /*
  816                                  * UIO_SYSSPACE may never happen, but handle
  817                                  * it just in case it does.
  818                                  */
  819                                 bcopy(uiop->uio_iov->iov_base, t_iov->iov_base,
  820                                     size);
  821                         bp->b_flags |= B_DIRECT;
  822                         bp->b_iocmd = BIO_WRITE;
  823                         if (cred != NOCRED) {
  824                                 crhold(cred);
  825                                 bp->b_wcred = cred;
  826                         } else
  827                                 bp->b_wcred = NOCRED;
  828                         bp->b_caller1 = (void *)t_uio;
  829                         bp->b_vp = vp;
  830                         error = ncl_asyncio(nmp, bp, NOCRED, td);
  831 err_free:
  832                         if (error) {
  833                                 free(t_iov->iov_base, M_NFSDIRECTIO);
  834                                 free(t_iov, M_NFSDIRECTIO);
  835                                 free(t_uio, M_NFSDIRECTIO);
  836                                 bp->b_vp = NULL;
  837                                 relpbuf(bp, &ncl_pbuf_freecnt);
  838                                 if (error == EINTR)
  839                                         return (error);
  840                                 goto do_sync;
  841                         }
  842                         uiop->uio_offset += size;
  843                         uiop->uio_resid -= size;
  844                         if (uiop->uio_iov->iov_len <= size) {
  845                                 uiop->uio_iovcnt--;
  846                                 uiop->uio_iov++;
  847                         } else {
  848                                 uiop->uio_iov->iov_base =
  849                                         (char *)uiop->uio_iov->iov_base + size;
  850                                 uiop->uio_iov->iov_len -= size;
  851                         }
  852                 }
  853         }
  854         return (0);
  855 }
  856 
  857 /*
  858  * Vnode op for write using bio
  859  */
  860 int
  861 ncl_write(struct vop_write_args *ap)
  862 {
  863         int biosize;
  864         struct uio *uio = ap->a_uio;
  865         struct thread *td = uio->uio_td;
  866         struct vnode *vp = ap->a_vp;
  867         struct nfsnode *np = VTONFS(vp);
  868         struct ucred *cred = ap->a_cred;
  869         int ioflag = ap->a_ioflag;
  870         struct buf *bp;
  871         struct vattr vattr;
  872         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  873         daddr_t lbn;
  874         int bcount, noncontig_write, obcount;
  875         int bp_cached, n, on, error = 0, error1, wouldcommit;
  876         size_t orig_resid, local_resid;
  877         off_t orig_size, tmp_off;
  878 
  879         KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
  880         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  881             ("ncl_write proc"));
  882         if (vp->v_type != VREG)
  883                 return (EIO);
  884         mtx_lock(&np->n_mtx);
  885         if (np->n_flag & NWRITEERR) {
  886                 np->n_flag &= ~NWRITEERR;
  887                 mtx_unlock(&np->n_mtx);
  888                 return (np->n_error);
  889         } else
  890                 mtx_unlock(&np->n_mtx);
  891         mtx_lock(&nmp->nm_mtx);
  892         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  893             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  894                 mtx_unlock(&nmp->nm_mtx);
  895                 (void)ncl_fsinfo(nmp, vp, cred, td);
  896                 mtx_lock(&nmp->nm_mtx);
  897         }
  898         if (nmp->nm_wsize == 0)
  899                 (void) newnfs_iosize(nmp);
  900         mtx_unlock(&nmp->nm_mtx);
  901 
  902         /*
  903          * Synchronously flush pending buffers if we are in synchronous
  904          * mode or if we are appending.
  905          */
  906         if (ioflag & (IO_APPEND | IO_SYNC)) {
  907                 mtx_lock(&np->n_mtx);
  908                 if (np->n_flag & NMODIFIED) {
  909                         mtx_unlock(&np->n_mtx);
  910 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
  911                         /*
  912                          * Require non-blocking, synchronous writes to
  913                          * dirty files to inform the program it needs
  914                          * to fsync(2) explicitly.
  915                          */
  916                         if (ioflag & IO_NDELAY)
  917                                 return (EAGAIN);
  918 #endif
  919                         np->n_attrstamp = 0;
  920                         KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  921                         error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
  922                             IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
  923                         if (error != 0)
  924                                 return (error);
  925                 } else
  926                         mtx_unlock(&np->n_mtx);
  927         }
  928 
  929         orig_resid = uio->uio_resid;
  930         mtx_lock(&np->n_mtx);
  931         orig_size = np->n_size;
  932         mtx_unlock(&np->n_mtx);
  933 
  934         /*
  935          * If IO_APPEND then load uio_offset.  We restart here if we cannot
  936          * get the append lock.
  937          */
  938         if (ioflag & IO_APPEND) {
  939                 np->n_attrstamp = 0;
  940                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  941                 error = VOP_GETATTR(vp, &vattr, cred);
  942                 if (error)
  943                         return (error);
  944                 mtx_lock(&np->n_mtx);
  945                 uio->uio_offset = np->n_size;
  946                 mtx_unlock(&np->n_mtx);
  947         }
  948 
  949         if (uio->uio_offset < 0)
  950                 return (EINVAL);
  951         tmp_off = uio->uio_offset + uio->uio_resid;
  952         if (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)
  953                 return (EFBIG);
  954         if (uio->uio_resid == 0)
  955                 return (0);
  956 
  957         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
  958                 return nfs_directio_write(vp, uio, cred, ioflag);
  959 
  960         /*
  961          * Maybe this should be above the vnode op call, but so long as
  962          * file servers have no limits, i don't think it matters
  963          */
  964         if (vn_rlimit_fsize(vp, uio, td))
  965                 return (EFBIG);
  966 
  967         biosize = vp->v_bufobj.bo_bsize;
  968         /*
  969          * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
  970          * would exceed the local maximum per-file write commit size when
  971          * combined with those, we must decide whether to flush,
  972          * go synchronous, or return error.  We don't bother checking
  973          * IO_UNIT -- we just make all writes atomic anyway, as there's
  974          * no point optimizing for something that really won't ever happen.
  975          */
  976         wouldcommit = 0;
  977         if (!(ioflag & IO_SYNC)) {
  978                 int nflag;
  979 
  980                 mtx_lock(&np->n_mtx);
  981                 nflag = np->n_flag;
  982                 mtx_unlock(&np->n_mtx);
  983                 if (nflag & NMODIFIED) {
  984                         BO_LOCK(&vp->v_bufobj);
  985                         if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
  986                                 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
  987                                     b_bobufs) {
  988                                         if (bp->b_flags & B_NEEDCOMMIT)
  989                                                 wouldcommit += bp->b_bcount;
  990                                 }
  991                         }
  992                         BO_UNLOCK(&vp->v_bufobj);
  993                 }
  994         }
  995 
  996         do {
  997                 if (!(ioflag & IO_SYNC)) {
  998                         wouldcommit += biosize;
  999                         if (wouldcommit > nmp->nm_wcommitsize) {
 1000                                 np->n_attrstamp = 0;
 1001                                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
 1002                                 error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
 1003                                     IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
 1004                                 if (error != 0)
 1005                                         return (error);
 1006                                 wouldcommit = biosize;
 1007                         }
 1008                 }
 1009 
 1010                 NFSINCRGLOBAL(nfsstatsv1.biocache_writes);
 1011                 lbn = uio->uio_offset / biosize;
 1012                 on = uio->uio_offset - (lbn * biosize);
 1013                 n = MIN((unsigned)(biosize - on), uio->uio_resid);
 1014 again:
 1015                 /*
 1016                  * Handle direct append and file extension cases, calculate
 1017                  * unaligned buffer size.
 1018                  */
 1019                 mtx_lock(&np->n_mtx);
 1020                 if ((np->n_flag & NHASBEENLOCKED) == 0 &&
 1021                     (nmp->nm_flag & NFSMNT_NONCONTIGWR) != 0)
 1022                         noncontig_write = 1;
 1023                 else
 1024                         noncontig_write = 0;
 1025                 if ((uio->uio_offset == np->n_size ||
 1026                     (noncontig_write != 0 &&
 1027                     lbn == (np->n_size / biosize) &&
 1028                     uio->uio_offset + n > np->n_size)) && n) {
 1029                         mtx_unlock(&np->n_mtx);
 1030                         /*
 1031                          * Get the buffer (in its pre-append state to maintain
 1032                          * B_CACHE if it was previously set).  Resize the
 1033                          * nfsnode after we have locked the buffer to prevent
 1034                          * readers from reading garbage.
 1035                          */
 1036                         obcount = np->n_size - (lbn * biosize);
 1037                         bp = nfs_getcacheblk(vp, lbn, obcount, td);
 1038 
 1039                         if (bp != NULL) {
 1040                                 long save;
 1041 
 1042                                 mtx_lock(&np->n_mtx);
 1043                                 np->n_size = uio->uio_offset + n;
 1044                                 np->n_flag |= NMODIFIED;
 1045                                 vnode_pager_setsize(vp, np->n_size);
 1046                                 mtx_unlock(&np->n_mtx);
 1047 
 1048                                 save = bp->b_flags & B_CACHE;
 1049                                 bcount = on + n;
 1050                                 allocbuf(bp, bcount);
 1051                                 bp->b_flags |= save;
 1052                                 if (noncontig_write != 0 && on > obcount)
 1053                                         vfs_bio_bzero_buf(bp, obcount, on -
 1054                                             obcount);
 1055                         }
 1056                 } else {
 1057                         /*
 1058                          * Obtain the locked cache block first, and then
 1059                          * adjust the file's size as appropriate.
 1060                          */
 1061                         bcount = on + n;
 1062                         if ((off_t)lbn * biosize + bcount < np->n_size) {
 1063                                 if ((off_t)(lbn + 1) * biosize < np->n_size)
 1064                                         bcount = biosize;
 1065                                 else
 1066                                         bcount = np->n_size - (off_t)lbn * biosize;
 1067                         }
 1068                         mtx_unlock(&np->n_mtx);
 1069                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1070                         mtx_lock(&np->n_mtx);
 1071                         if (uio->uio_offset + n > np->n_size) {
 1072                                 np->n_size = uio->uio_offset + n;
 1073                                 np->n_flag |= NMODIFIED;
 1074                                 vnode_pager_setsize(vp, np->n_size);
 1075                         }
 1076                         mtx_unlock(&np->n_mtx);
 1077                 }
 1078 
 1079                 if (!bp) {
 1080                         error = newnfs_sigintr(nmp, td);
 1081                         if (!error)
 1082                                 error = EINTR;
 1083                         break;
 1084                 }
 1085 
 1086                 /*
 1087                  * Issue a READ if B_CACHE is not set.  In special-append
 1088                  * mode, B_CACHE is based on the buffer prior to the write
 1089                  * op and is typically set, avoiding the read.  If a read
 1090                  * is required in special append mode, the server will
 1091                  * probably send us a short-read since we extended the file
 1092                  * on our end, resulting in b_resid == 0 and, thusly,
 1093                  * B_CACHE getting set.
 1094                  *
 1095                  * We can also avoid issuing the read if the write covers
 1096                  * the entire buffer.  We have to make sure the buffer state
 1097                  * is reasonable in this case since we will not be initiating
 1098                  * I/O.  See the comments in kern/vfs_bio.c's getblk() for
 1099                  * more information.
 1100                  *
 1101                  * B_CACHE may also be set due to the buffer being cached
 1102                  * normally.
 1103                  */
 1104 
 1105                 bp_cached = 1;
 1106                 if (on == 0 && n == bcount) {
 1107                         if ((bp->b_flags & B_CACHE) == 0)
 1108                                 bp_cached = 0;
 1109                         bp->b_flags |= B_CACHE;
 1110                         bp->b_flags &= ~B_INVAL;
 1111                         bp->b_ioflags &= ~BIO_ERROR;
 1112                 }
 1113 
 1114                 if ((bp->b_flags & B_CACHE) == 0) {
 1115                         bp->b_iocmd = BIO_READ;
 1116                         vfs_busy_pages(bp, 0);
 1117                         error = ncl_doio(vp, bp, cred, td, 0);
 1118                         if (error) {
 1119                                 brelse(bp);
 1120                                 break;
 1121                         }
 1122                 }
 1123                 if (bp->b_wcred == NOCRED)
 1124                         bp->b_wcred = crhold(cred);
 1125                 mtx_lock(&np->n_mtx);
 1126                 np->n_flag |= NMODIFIED;
 1127                 mtx_unlock(&np->n_mtx);
 1128 
 1129                 /*
 1130                  * If dirtyend exceeds file size, chop it down.  This should
 1131                  * not normally occur but there is an append race where it
 1132                  * might occur XXX, so we log it.
 1133                  *
 1134                  * If the chopping creates a reverse-indexed or degenerate
 1135                  * situation with dirtyoff/end, we 0 both of them.
 1136                  */
 1137 
 1138                 if (bp->b_dirtyend > bcount) {
 1139                         printf("NFS append race @%lx:%d\n",
 1140                             (long)bp->b_blkno * DEV_BSIZE,
 1141                             bp->b_dirtyend - bcount);
 1142                         bp->b_dirtyend = bcount;
 1143                 }
 1144 
 1145                 if (bp->b_dirtyoff >= bp->b_dirtyend)
 1146                         bp->b_dirtyoff = bp->b_dirtyend = 0;
 1147 
 1148                 /*
 1149                  * If the new write will leave a contiguous dirty
 1150                  * area, just update the b_dirtyoff and b_dirtyend,
 1151                  * otherwise force a write rpc of the old dirty area.
 1152                  *
 1153                  * If there has been a file lock applied to this file
 1154                  * or vfs.nfs.old_noncontig_writing is set, do the following:
 1155                  * While it is possible to merge discontiguous writes due to
 1156                  * our having a B_CACHE buffer ( and thus valid read data
 1157                  * for the hole), we don't because it could lead to
 1158                  * significant cache coherency problems with multiple clients,
 1159                  * especially if locking is implemented later on.
 1160                  *
 1161                  * If vfs.nfs.old_noncontig_writing is not set and there has
 1162                  * not been file locking done on this file:
 1163                  * Relax coherency a bit for the sake of performance and
 1164                  * expand the current dirty region to contain the new
 1165                  * write even if it means we mark some non-dirty data as
 1166                  * dirty.
 1167                  */
 1168 
 1169                 if (noncontig_write == 0 && bp->b_dirtyend > 0 &&
 1170                     (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
 1171                         if (bwrite(bp) == EINTR) {
 1172                                 error = EINTR;
 1173                                 break;
 1174                         }
 1175                         goto again;
 1176                 }
 1177 
 1178                 local_resid = uio->uio_resid;
 1179                 error = vn_io_fault_uiomove((char *)bp->b_data + on, n, uio);
 1180 
 1181                 if (error != 0 && !bp_cached) {
 1182                         /*
 1183                          * This block has no other content then what
 1184                          * possibly was written by the faulty uiomove.
 1185                          * Release it, forgetting the data pages, to
 1186                          * prevent the leak of uninitialized data to
 1187                          * usermode.
 1188                          */
 1189                         bp->b_ioflags |= BIO_ERROR;
 1190                         brelse(bp);
 1191                         uio->uio_offset -= local_resid - uio->uio_resid;
 1192                         uio->uio_resid = local_resid;
 1193                         break;
 1194                 }
 1195 
 1196                 /*
 1197                  * Since this block is being modified, it must be written
 1198                  * again and not just committed.  Since write clustering does
 1199                  * not work for the stage 1 data write, only the stage 2
 1200                  * commit rpc, we have to clear B_CLUSTEROK as well.
 1201                  */
 1202                 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1203 
 1204                 /*
 1205                  * Get the partial update on the progress made from
 1206                  * uiomove, if an error occurred.
 1207                  */
 1208                 if (error != 0)
 1209                         n = local_resid - uio->uio_resid;
 1210 
 1211                 /*
 1212                  * Only update dirtyoff/dirtyend if not a degenerate
 1213                  * condition.
 1214                  */
 1215                 if (n > 0) {
 1216                         if (bp->b_dirtyend > 0) {
 1217                                 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
 1218                                 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
 1219                         } else {
 1220                                 bp->b_dirtyoff = on;
 1221                                 bp->b_dirtyend = on + n;
 1222                         }
 1223                         vfs_bio_set_valid(bp, on, n);
 1224                 }
 1225 
 1226                 /*
 1227                  * If IO_SYNC do bwrite().
 1228                  *
 1229                  * IO_INVAL appears to be unused.  The idea appears to be
 1230                  * to turn off caching in this case.  Very odd.  XXX
 1231                  */
 1232                 if ((ioflag & IO_SYNC)) {
 1233                         if (ioflag & IO_INVAL)
 1234                                 bp->b_flags |= B_NOCACHE;
 1235                         error1 = bwrite(bp);
 1236                         if (error1 != 0) {
 1237                                 if (error == 0)
 1238                                         error = error1;
 1239                                 break;
 1240                         }
 1241                 } else if ((n + on) == biosize || (ioflag & IO_ASYNC) != 0) {
 1242                         bp->b_flags |= B_ASYNC;
 1243                         (void) ncl_writebp(bp, 0, NULL);
 1244                 } else {
 1245                         bdwrite(bp);
 1246                 }
 1247 
 1248                 if (error != 0)
 1249                         break;
 1250         } while (uio->uio_resid > 0 && n > 0);
 1251 
 1252         if (error != 0) {
 1253                 if (ioflag & IO_UNIT) {
 1254                         VATTR_NULL(&vattr);
 1255                         vattr.va_size = orig_size;
 1256                         /* IO_SYNC is handled implicitely */
 1257                         (void)VOP_SETATTR(vp, &vattr, cred);
 1258                         uio->uio_offset -= orig_resid - uio->uio_resid;
 1259                         uio->uio_resid = orig_resid;
 1260                 }
 1261         }
 1262 
 1263         return (error);
 1264 }
 1265 
 1266 /*
 1267  * Get an nfs cache block.
 1268  *
 1269  * Allocate a new one if the block isn't currently in the cache
 1270  * and return the block marked busy. If the calling process is
 1271  * interrupted by a signal for an interruptible mount point, return
 1272  * NULL.
 1273  *
 1274  * The caller must carefully deal with the possible B_INVAL state of
 1275  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
 1276  * indirectly), so synchronous reads can be issued without worrying about
 1277  * the B_INVAL state.  We have to be a little more careful when dealing
 1278  * with writes (see comments in nfs_write()) when extending a file past
 1279  * its EOF.
 1280  */
 1281 static struct buf *
 1282 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
 1283 {
 1284         struct buf *bp;
 1285         struct mount *mp;
 1286         struct nfsmount *nmp;
 1287 
 1288         mp = vp->v_mount;
 1289         nmp = VFSTONFS(mp);
 1290 
 1291         if (nmp->nm_flag & NFSMNT_INT) {
 1292                 sigset_t oldset;
 1293 
 1294                 newnfs_set_sigmask(td, &oldset);
 1295                 bp = getblk(vp, bn, size, PCATCH, 0, 0);
 1296                 newnfs_restore_sigmask(td, &oldset);
 1297                 while (bp == NULL) {
 1298                         if (newnfs_sigintr(nmp, td))
 1299                                 return (NULL);
 1300                         bp = getblk(vp, bn, size, 0, 2 * hz, 0);
 1301                 }
 1302         } else {
 1303                 bp = getblk(vp, bn, size, 0, 0, 0);
 1304         }
 1305 
 1306         if (vp->v_type == VREG)
 1307                 bp->b_blkno = bn * (vp->v_bufobj.bo_bsize / DEV_BSIZE);
 1308         return (bp);
 1309 }
 1310 
 1311 /*
 1312  * Flush and invalidate all dirty buffers. If another process is already
 1313  * doing the flush, just wait for completion.
 1314  */
 1315 int
 1316 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
 1317 {
 1318         struct nfsnode *np = VTONFS(vp);
 1319         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 1320         int error = 0, slpflag, slptimeo;
 1321         bool old_lock;
 1322 
 1323         ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
 1324 
 1325         if ((nmp->nm_flag & NFSMNT_INT) == 0)
 1326                 intrflg = 0;
 1327         if (NFSCL_FORCEDISM(nmp->nm_mountp))
 1328                 intrflg = 1;
 1329         if (intrflg) {
 1330                 slpflag = PCATCH;
 1331                 slptimeo = 2 * hz;
 1332         } else {
 1333                 slpflag = 0;
 1334                 slptimeo = 0;
 1335         }
 1336 
 1337         old_lock = ncl_excl_start(vp);
 1338         if (old_lock)
 1339                 flags |= V_ALLOWCLEAN;
 1340 
 1341         /*
 1342          * Now, flush as required.
 1343          */
 1344         if ((flags & (V_SAVE | V_VMIO)) == V_SAVE &&
 1345              vp->v_bufobj.bo_object != NULL) {
 1346                 VM_OBJECT_WLOCK(vp->v_bufobj.bo_object);
 1347                 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
 1348                 VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object);
 1349                 /*
 1350                  * If the page clean was interrupted, fail the invalidation.
 1351                  * Not doing so, we run the risk of losing dirty pages in the
 1352                  * vinvalbuf() call below.
 1353                  */
 1354                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1355                         goto out;
 1356         }
 1357 
 1358         error = vinvalbuf(vp, flags, slpflag, 0);
 1359         while (error) {
 1360                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1361                         goto out;
 1362                 error = vinvalbuf(vp, flags, 0, slptimeo);
 1363         }
 1364         if (NFSHASPNFS(nmp)) {
 1365                 nfscl_layoutcommit(vp, td);
 1366                 /*
 1367                  * Invalidate the attribute cache, since writes to a DS
 1368                  * won't update the size attribute.
 1369                  */
 1370                 mtx_lock(&np->n_mtx);
 1371                 np->n_attrstamp = 0;
 1372         } else
 1373                 mtx_lock(&np->n_mtx);
 1374         if (np->n_directio_asyncwr == 0)
 1375                 np->n_flag &= ~NMODIFIED;
 1376         mtx_unlock(&np->n_mtx);
 1377 out:
 1378         ncl_excl_finish(vp, old_lock);
 1379         return error;
 1380 }
 1381 
 1382 /*
 1383  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
 1384  * This is mainly to avoid queueing async I/O requests when the nfsiods
 1385  * are all hung on a dead server.
 1386  *
 1387  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
 1388  * is eventually dequeued by the async daemon, ncl_doio() *will*.
 1389  */
 1390 int
 1391 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
 1392 {
 1393         int iod;
 1394         int gotiod;
 1395         int slpflag = 0;
 1396         int slptimeo = 0;
 1397         int error, error2;
 1398 
 1399         /*
 1400          * Commits are usually short and sweet so lets save some cpu and
 1401          * leave the async daemons for more important rpc's (such as reads
 1402          * and writes).
 1403          *
 1404          * Readdirplus RPCs do vget()s to acquire the vnodes for entries
 1405          * in the directory in order to update attributes. This can deadlock
 1406          * with another thread that is waiting for async I/O to be done by
 1407          * an nfsiod thread while holding a lock on one of these vnodes.
 1408          * To avoid this deadlock, don't allow the async nfsiod threads to
 1409          * perform Readdirplus RPCs.
 1410          */
 1411         mtx_lock(&ncl_iod_mutex);
 1412         if ((bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
 1413              (nmp->nm_bufqiods > ncl_numasync / 2)) ||
 1414             (bp->b_vp->v_type == VDIR && (nmp->nm_flag & NFSMNT_RDIRPLUS))) {
 1415                 mtx_unlock(&ncl_iod_mutex);
 1416                 return(EIO);
 1417         }
 1418 again:
 1419         if (nmp->nm_flag & NFSMNT_INT)
 1420                 slpflag = PCATCH;
 1421         gotiod = FALSE;
 1422 
 1423         /*
 1424          * Find a free iod to process this request.
 1425          */
 1426         for (iod = 0; iod < ncl_numasync; iod++)
 1427                 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
 1428                         gotiod = TRUE;
 1429                         break;
 1430                 }
 1431 
 1432         /*
 1433          * Try to create one if none are free.
 1434          */
 1435         if (!gotiod)
 1436                 ncl_nfsiodnew();
 1437         else {
 1438                 /*
 1439                  * Found one, so wake it up and tell it which
 1440                  * mount to process.
 1441                  */
 1442                 NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
 1443                     iod, nmp));
 1444                 ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
 1445                 ncl_iodmount[iod] = nmp;
 1446                 nmp->nm_bufqiods++;
 1447                 wakeup(&ncl_iodwant[iod]);
 1448         }
 1449 
 1450         /*
 1451          * If none are free, we may already have an iod working on this mount
 1452          * point.  If so, it will process our request.
 1453          */
 1454         if (!gotiod) {
 1455                 if (nmp->nm_bufqiods > 0) {
 1456                         NFS_DPF(ASYNCIO,
 1457                                 ("ncl_asyncio: %d iods are already processing mount %p\n",
 1458                                  nmp->nm_bufqiods, nmp));
 1459                         gotiod = TRUE;
 1460                 }
 1461         }
 1462 
 1463         /*
 1464          * If we have an iod which can process the request, then queue
 1465          * the buffer.
 1466          */
 1467         if (gotiod) {
 1468                 /*
 1469                  * Ensure that the queue never grows too large.  We still want
 1470                  * to asynchronize so we block rather then return EIO.
 1471                  */
 1472                 while (nmp->nm_bufqlen >= 2*ncl_numasync) {
 1473                         NFS_DPF(ASYNCIO,
 1474                                 ("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
 1475                         nmp->nm_bufqwant = TRUE;
 1476                         error = newnfs_msleep(td, &nmp->nm_bufq,
 1477                             &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
 1478                            slptimeo);
 1479                         if (error) {
 1480                                 error2 = newnfs_sigintr(nmp, td);
 1481                                 if (error2) {
 1482                                         mtx_unlock(&ncl_iod_mutex);
 1483                                         return (error2);
 1484                                 }
 1485                                 if (slpflag == PCATCH) {
 1486                                         slpflag = 0;
 1487                                         slptimeo = 2 * hz;
 1488                                 }
 1489                         }
 1490                         /*
 1491                          * We might have lost our iod while sleeping,
 1492                          * so check and loop if necessary.
 1493                          */
 1494                         goto again;
 1495                 }
 1496 
 1497                 /* We might have lost our nfsiod */
 1498                 if (nmp->nm_bufqiods == 0) {
 1499                         NFS_DPF(ASYNCIO,
 1500                                 ("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
 1501                         goto again;
 1502                 }
 1503 
 1504                 if (bp->b_iocmd == BIO_READ) {
 1505                         if (bp->b_rcred == NOCRED && cred != NOCRED)
 1506                                 bp->b_rcred = crhold(cred);
 1507                 } else {
 1508                         if (bp->b_wcred == NOCRED && cred != NOCRED)
 1509                                 bp->b_wcred = crhold(cred);
 1510                 }
 1511 
 1512                 if (bp->b_flags & B_REMFREE)
 1513                         bremfreef(bp);
 1514                 BUF_KERNPROC(bp);
 1515                 TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
 1516                 nmp->nm_bufqlen++;
 1517                 if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1518                         mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);
 1519                         VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
 1520                         VTONFS(bp->b_vp)->n_directio_asyncwr++;
 1521                         mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
 1522                 }
 1523                 mtx_unlock(&ncl_iod_mutex);
 1524                 return (0);
 1525         }
 1526 
 1527         mtx_unlock(&ncl_iod_mutex);
 1528 
 1529         /*
 1530          * All the iods are busy on other mounts, so return EIO to
 1531          * force the caller to process the i/o synchronously.
 1532          */
 1533         NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
 1534         return (EIO);
 1535 }
 1536 
 1537 void
 1538 ncl_doio_directwrite(struct buf *bp)
 1539 {
 1540         int iomode, must_commit;
 1541         struct uio *uiop = (struct uio *)bp->b_caller1;
 1542         char *iov_base = uiop->uio_iov->iov_base;
 1543 
 1544         iomode = NFSWRITE_FILESYNC;
 1545         uiop->uio_td = NULL; /* NULL since we're in nfsiod */
 1546         ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
 1547         KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
 1548         free(iov_base, M_NFSDIRECTIO);
 1549         free(uiop->uio_iov, M_NFSDIRECTIO);
 1550         free(uiop, M_NFSDIRECTIO);
 1551         if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1552                 struct nfsnode *np = VTONFS(bp->b_vp);
 1553                 mtx_lock(&np->n_mtx);
 1554                 if (NFSHASPNFS(VFSTONFS(vnode_mount(bp->b_vp)))) {
 1555                         /*
 1556                          * Invalidate the attribute cache, since writes to a DS
 1557                          * won't update the size attribute.
 1558                          */
 1559                         np->n_attrstamp = 0;
 1560                 }
 1561                 np->n_directio_asyncwr--;
 1562                 if (np->n_directio_asyncwr == 0) {
 1563                         np->n_flag &= ~NMODIFIED;
 1564                         if ((np->n_flag & NFSYNCWAIT)) {
 1565                                 np->n_flag &= ~NFSYNCWAIT;
 1566                                 wakeup((caddr_t)&np->n_directio_asyncwr);
 1567                         }
 1568                 }
 1569                 mtx_unlock(&np->n_mtx);
 1570         }
 1571         bp->b_vp = NULL;
 1572         relpbuf(bp, &ncl_pbuf_freecnt);
 1573 }
 1574 
 1575 /*
 1576  * Do an I/O operation to/from a cache block. This may be called
 1577  * synchronously or from an nfsiod.
 1578  */
 1579 int
 1580 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
 1581     int called_from_strategy)
 1582 {
 1583         struct uio *uiop;
 1584         struct nfsnode *np;
 1585         struct nfsmount *nmp;
 1586         int error = 0, iomode, must_commit = 0;
 1587         struct uio uio;
 1588         struct iovec io;
 1589         struct proc *p = td ? td->td_proc : NULL;
 1590         uint8_t iocmd;
 1591 
 1592         np = VTONFS(vp);
 1593         nmp = VFSTONFS(vp->v_mount);
 1594         uiop = &uio;
 1595         uiop->uio_iov = &io;
 1596         uiop->uio_iovcnt = 1;
 1597         uiop->uio_segflg = UIO_SYSSPACE;
 1598         uiop->uio_td = td;
 1599 
 1600         /*
 1601          * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
 1602          * do this here so we do not have to do it in all the code that
 1603          * calls us.
 1604          */
 1605         bp->b_flags &= ~B_INVAL;
 1606         bp->b_ioflags &= ~BIO_ERROR;
 1607 
 1608         KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
 1609         iocmd = bp->b_iocmd;
 1610         if (iocmd == BIO_READ) {
 1611             io.iov_len = uiop->uio_resid = bp->b_bcount;
 1612             io.iov_base = bp->b_data;
 1613             uiop->uio_rw = UIO_READ;
 1614 
 1615             switch (vp->v_type) {
 1616             case VREG:
 1617                 uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
 1618                 NFSINCRGLOBAL(nfsstatsv1.read_bios);
 1619                 error = ncl_readrpc(vp, uiop, cr);
 1620 
 1621                 if (!error) {
 1622                     if (uiop->uio_resid) {
 1623                         /*
 1624                          * If we had a short read with no error, we must have
 1625                          * hit a file hole.  We should zero-fill the remainder.
 1626                          * This can also occur if the server hits the file EOF.
 1627                          *
 1628                          * Holes used to be able to occur due to pending
 1629                          * writes, but that is not possible any longer.
 1630                          */
 1631                         int nread = bp->b_bcount - uiop->uio_resid;
 1632                         ssize_t left = uiop->uio_resid;
 1633 
 1634                         if (left > 0)
 1635                                 bzero((char *)bp->b_data + nread, left);
 1636                         uiop->uio_resid = 0;
 1637                     }
 1638                 }
 1639                 /* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
 1640                 if (p && (vp->v_vflag & VV_TEXT)) {
 1641                         mtx_lock(&np->n_mtx);
 1642                         if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
 1643                                 mtx_unlock(&np->n_mtx);
 1644                                 PROC_LOCK(p);
 1645                                 killproc(p, "text file modification");
 1646                                 PROC_UNLOCK(p);
 1647                         } else
 1648                                 mtx_unlock(&np->n_mtx);
 1649                 }
 1650                 break;
 1651             case VLNK:
 1652                 uiop->uio_offset = (off_t)0;
 1653                 NFSINCRGLOBAL(nfsstatsv1.readlink_bios);
 1654                 error = ncl_readlinkrpc(vp, uiop, cr);
 1655                 break;
 1656             case VDIR:
 1657                 NFSINCRGLOBAL(nfsstatsv1.readdir_bios);
 1658                 uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
 1659                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
 1660                         error = ncl_readdirplusrpc(vp, uiop, cr, td);
 1661                         if (error == NFSERR_NOTSUPP)
 1662                                 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
 1663                 }
 1664                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
 1665                         error = ncl_readdirrpc(vp, uiop, cr, td);
 1666                 /*
 1667                  * end-of-directory sets B_INVAL but does not generate an
 1668                  * error.
 1669                  */
 1670                 if (error == 0 && uiop->uio_resid == bp->b_bcount)
 1671                         bp->b_flags |= B_INVAL;
 1672                 break;
 1673             default:
 1674                 printf("ncl_doio:  type %x unexpected\n", vp->v_type);
 1675                 break;
 1676             }
 1677             if (error) {
 1678                 bp->b_ioflags |= BIO_ERROR;
 1679                 bp->b_error = error;
 1680             }
 1681         } else {
 1682             /*
 1683              * If we only need to commit, try to commit
 1684              */
 1685             if (bp->b_flags & B_NEEDCOMMIT) {
 1686                     int retv;
 1687                     off_t off;
 1688 
 1689                     off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
 1690                     retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
 1691                         bp->b_wcred, td);
 1692                     if (retv == 0) {
 1693                             bp->b_dirtyoff = bp->b_dirtyend = 0;
 1694                             bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1695                             bp->b_resid = 0;
 1696                             bufdone(bp);
 1697                             return (0);
 1698                     }
 1699                     if (retv == NFSERR_STALEWRITEVERF) {
 1700                             ncl_clearcommit(vp->v_mount);
 1701                     }
 1702             }
 1703 
 1704             /*
 1705              * Setup for actual write
 1706              */
 1707             mtx_lock(&np->n_mtx);
 1708             if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
 1709                 bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
 1710             mtx_unlock(&np->n_mtx);
 1711 
 1712             if (bp->b_dirtyend > bp->b_dirtyoff) {
 1713                 io.iov_len = uiop->uio_resid = bp->b_dirtyend
 1714                     - bp->b_dirtyoff;
 1715                 uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
 1716                     + bp->b_dirtyoff;
 1717                 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
 1718                 uiop->uio_rw = UIO_WRITE;
 1719                 NFSINCRGLOBAL(nfsstatsv1.write_bios);
 1720 
 1721                 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
 1722                     iomode = NFSWRITE_UNSTABLE;
 1723                 else
 1724                     iomode = NFSWRITE_FILESYNC;
 1725 
 1726                 error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
 1727                     called_from_strategy);
 1728 
 1729                 /*
 1730                  * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
 1731                  * to cluster the buffers needing commit.  This will allow
 1732                  * the system to submit a single commit rpc for the whole
 1733                  * cluster.  We can do this even if the buffer is not 100%
 1734                  * dirty (relative to the NFS blocksize), so we optimize the
 1735                  * append-to-file-case.
 1736                  *
 1737                  * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
 1738                  * cleared because write clustering only works for commit
 1739                  * rpc's, not for the data portion of the write).
 1740                  */
 1741 
 1742                 if (!error && iomode == NFSWRITE_UNSTABLE) {
 1743                     bp->b_flags |= B_NEEDCOMMIT;
 1744                     if (bp->b_dirtyoff == 0
 1745                         && bp->b_dirtyend == bp->b_bcount)
 1746                         bp->b_flags |= B_CLUSTEROK;
 1747                 } else {
 1748                     bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1749                 }
 1750 
 1751                 /*
 1752                  * For an interrupted write, the buffer is still valid
 1753                  * and the write hasn't been pushed to the server yet,
 1754                  * so we can't set BIO_ERROR and report the interruption
 1755                  * by setting B_EINTR. For the B_ASYNC case, B_EINTR
 1756                  * is not relevant, so the rpc attempt is essentially
 1757                  * a noop.  For the case of a V3 write rpc not being
 1758                  * committed to stable storage, the block is still
 1759                  * dirty and requires either a commit rpc or another
 1760                  * write rpc with iomode == NFSV3WRITE_FILESYNC before
 1761                  * the block is reused. This is indicated by setting
 1762                  * the B_DELWRI and B_NEEDCOMMIT flags.
 1763                  *
 1764                  * EIO is returned by ncl_writerpc() to indicate a recoverable
 1765                  * write error and is handled as above, except that
 1766                  * B_EINTR isn't set. One cause of this is a stale stateid
 1767                  * error for the RPC that indicates recovery is required,
 1768                  * when called with called_from_strategy != 0.
 1769                  *
 1770                  * If the buffer is marked B_PAGING, it does not reside on
 1771                  * the vp's paging queues so we cannot call bdirty().  The
 1772                  * bp in this case is not an NFS cache block so we should
 1773                  * be safe. XXX
 1774                  *
 1775                  * The logic below breaks up errors into recoverable and
 1776                  * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
 1777                  * and keep the buffer around for potential write retries.
 1778                  * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
 1779                  * and save the error in the nfsnode. This is less than ideal
 1780                  * but necessary. Keeping such buffers around could potentially
 1781                  * cause buffer exhaustion eventually (they can never be written
 1782                  * out, so will get constantly be re-dirtied). It also causes
 1783                  * all sorts of vfs panics. For non-recoverable write errors,
 1784                  * also invalidate the attrcache, so we'll be forced to go over
 1785                  * the wire for this object, returning an error to user on next
 1786                  * call (most of the time).
 1787                  */
 1788                 if (error == EINTR || error == EIO || error == ETIMEDOUT
 1789                     || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
 1790                         bp->b_flags &= ~(B_INVAL|B_NOCACHE);
 1791                         if ((bp->b_flags & B_PAGING) == 0) {
 1792                             bdirty(bp);
 1793                             bp->b_flags &= ~B_DONE;
 1794                         }
 1795                         if ((error == EINTR || error == ETIMEDOUT) &&
 1796                             (bp->b_flags & B_ASYNC) == 0)
 1797                             bp->b_flags |= B_EINTR;
 1798                 } else {
 1799                     if (error) {
 1800                         bp->b_ioflags |= BIO_ERROR;
 1801                         bp->b_flags |= B_INVAL;
 1802                         bp->b_error = np->n_error = error;
 1803                         mtx_lock(&np->n_mtx);
 1804                         np->n_flag |= NWRITEERR;
 1805                         np->n_attrstamp = 0;
 1806                         KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
 1807                         mtx_unlock(&np->n_mtx);
 1808                     }
 1809                     bp->b_dirtyoff = bp->b_dirtyend = 0;
 1810                 }
 1811             } else {
 1812                 bp->b_resid = 0;
 1813                 bufdone(bp);
 1814                 return (0);
 1815             }
 1816         }
 1817         bp->b_resid = uiop->uio_resid;
 1818         if (must_commit)
 1819             ncl_clearcommit(vp->v_mount);
 1820         bufdone(bp);
 1821         return (error);
 1822 }
 1823 
 1824 /*
 1825  * Used to aid in handling ftruncate() operations on the NFS client side.
 1826  * Truncation creates a number of special problems for NFS.  We have to
 1827  * throw away VM pages and buffer cache buffers that are beyond EOF, and
 1828  * we have to properly handle VM pages or (potentially dirty) buffers
 1829  * that straddle the truncation point.
 1830  */
 1831 
 1832 int
 1833 ncl_meta_setsize(struct vnode *vp, struct thread *td, u_quad_t nsize)
 1834 {
 1835         struct nfsnode *np = VTONFS(vp);
 1836         u_quad_t tsize;
 1837         int biosize = vp->v_bufobj.bo_bsize;
 1838         int error = 0;
 1839 
 1840         mtx_lock(&np->n_mtx);
 1841         tsize = np->n_size;
 1842         np->n_size = nsize;
 1843         mtx_unlock(&np->n_mtx);
 1844 
 1845         if (nsize < tsize) {
 1846                 struct buf *bp;
 1847                 daddr_t lbn;
 1848                 int bufsize;
 1849 
 1850                 /*
 1851                  * vtruncbuf() doesn't get the buffer overlapping the
 1852                  * truncation point.  We may have a B_DELWRI and/or B_CACHE
 1853                  * buffer that now needs to be truncated.
 1854                  */
 1855                 error = vtruncbuf(vp, nsize, biosize);
 1856                 lbn = nsize / biosize;
 1857                 bufsize = nsize - (lbn * biosize);
 1858                 bp = nfs_getcacheblk(vp, lbn, bufsize, td);
 1859                 if (!bp)
 1860                         return EINTR;
 1861                 if (bp->b_dirtyoff > bp->b_bcount)
 1862                         bp->b_dirtyoff = bp->b_bcount;
 1863                 if (bp->b_dirtyend > bp->b_bcount)
 1864                         bp->b_dirtyend = bp->b_bcount;
 1865                 bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
 1866                 brelse(bp);
 1867         } else {
 1868                 vnode_pager_setsize(vp, nsize);
 1869         }
 1870         return(error);
 1871 }
 1872 

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