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  * SPDX-License-Identifier: BSD-3-Clause
    3  *
    4  * Copyright (c) 1989, 1993
    5  *      The Regents of the University of California.  All rights reserved.
    6  *
    7  * This code is derived from software contributed to Berkeley by
    8  * Rick Macklem at The University of Guelph.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 3. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)nfs_bio.c   8.9 (Berkeley) 3/30/95
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: head/sys/fs/nfsclient/nfs_clbio.c 343030 2019-01-15 01:02:16Z glebius $");
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/bio.h>
   43 #include <sys/buf.h>
   44 #include <sys/kernel.h>
   45 #include <sys/mount.h>
   46 #include <sys/rwlock.h>
   47 #include <sys/vmmeter.h>
   48 #include <sys/vnode.h>
   49 
   50 #include <vm/vm.h>
   51 #include <vm/vm_param.h>
   52 #include <vm/vm_extern.h>
   53 #include <vm/vm_page.h>
   54 #include <vm/vm_object.h>
   55 #include <vm/vm_pager.h>
   56 #include <vm/vnode_pager.h>
   57 
   58 #include <fs/nfs/nfsport.h>
   59 #include <fs/nfsclient/nfsmount.h>
   60 #include <fs/nfsclient/nfs.h>
   61 #include <fs/nfsclient/nfsnode.h>
   62 #include <fs/nfsclient/nfs_kdtrace.h>
   63 
   64 extern int newnfs_directio_allow_mmap;
   65 extern struct nfsstatsv1 nfsstatsv1;
   66 extern struct mtx ncl_iod_mutex;
   67 extern int ncl_numasync;
   68 extern enum nfsiod_state ncl_iodwant[NFS_MAXASYNCDAEMON];
   69 extern struct nfsmount *ncl_iodmount[NFS_MAXASYNCDAEMON];
   70 extern int newnfs_directio_enable;
   71 extern int nfs_keep_dirty_on_error;
   72 
   73 uma_zone_t ncl_pbuf_zone;
   74 
   75 static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
   76     struct thread *td);
   77 static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
   78     struct ucred *cred, int ioflag);
   79 
   80 /*
   81  * Vnode op for VM getpages.
   82  */
   83 SYSCTL_DECL(_vfs_nfs);
   84 static int use_buf_pager = 1;
   85 SYSCTL_INT(_vfs_nfs, OID_AUTO, use_buf_pager, CTLFLAG_RWTUN,
   86     &use_buf_pager, 0,
   87     "Use buffer pager instead of direct readrpc call");
   88 
   89 static daddr_t
   90 ncl_gbp_getblkno(struct vnode *vp, vm_ooffset_t off)
   91 {
   92 
   93         return (off / vp->v_bufobj.bo_bsize);
   94 }
   95 
   96 static int
   97 ncl_gbp_getblksz(struct vnode *vp, daddr_t lbn)
   98 {
   99         struct nfsnode *np;
  100         u_quad_t nsize;
  101         int biosize, bcount;
  102 
  103         np = VTONFS(vp);
  104         mtx_lock(&np->n_mtx);
  105         nsize = np->n_size;
  106         mtx_unlock(&np->n_mtx);
  107 
  108         biosize = vp->v_bufobj.bo_bsize;
  109         bcount = biosize;
  110         if ((off_t)lbn * biosize >= nsize)
  111                 bcount = 0;
  112         else if ((off_t)(lbn + 1) * biosize > nsize)
  113                 bcount = nsize - (off_t)lbn * biosize;
  114         return (bcount);
  115 }
  116 
  117 int
  118 ncl_getpages(struct vop_getpages_args *ap)
  119 {
  120         int i, error, nextoff, size, toff, count, npages;
  121         struct uio uio;
  122         struct iovec iov;
  123         vm_offset_t kva;
  124         struct buf *bp;
  125         struct vnode *vp;
  126         struct thread *td;
  127         struct ucred *cred;
  128         struct nfsmount *nmp;
  129         vm_object_t object;
  130         vm_page_t *pages;
  131         struct nfsnode *np;
  132 
  133         vp = ap->a_vp;
  134         np = VTONFS(vp);
  135         td = curthread;
  136         cred = curthread->td_ucred;
  137         nmp = VFSTONFS(vp->v_mount);
  138         pages = ap->a_m;
  139         npages = ap->a_count;
  140 
  141         if ((object = vp->v_object) == NULL) {
  142                 printf("ncl_getpages: called with non-merged cache vnode\n");
  143                 return (VM_PAGER_ERROR);
  144         }
  145 
  146         if (newnfs_directio_enable && !newnfs_directio_allow_mmap) {
  147                 mtx_lock(&np->n_mtx);
  148                 if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  149                         mtx_unlock(&np->n_mtx);
  150                         printf("ncl_getpages: called on non-cacheable vnode\n");
  151                         return (VM_PAGER_ERROR);
  152                 } else
  153                         mtx_unlock(&np->n_mtx);
  154         }
  155 
  156         mtx_lock(&nmp->nm_mtx);
  157         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  158             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  159                 mtx_unlock(&nmp->nm_mtx);
  160                 /* We'll never get here for v4, because we always have fsinfo */
  161                 (void)ncl_fsinfo(nmp, vp, cred, td);
  162         } else
  163                 mtx_unlock(&nmp->nm_mtx);
  164 
  165         if (use_buf_pager)
  166                 return (vfs_bio_getpages(vp, pages, npages, ap->a_rbehind,
  167                     ap->a_rahead, ncl_gbp_getblkno, ncl_gbp_getblksz));
  168 
  169         /*
  170          * If the requested page is partially valid, just return it and
  171          * allow the pager to zero-out the blanks.  Partially valid pages
  172          * can only occur at the file EOF.
  173          *
  174          * XXXGL: is that true for NFS, where short read can occur???
  175          */
  176         VM_OBJECT_WLOCK(object);
  177         if (pages[npages - 1]->valid != 0 && --npages == 0)
  178                 goto out;
  179         VM_OBJECT_WUNLOCK(object);
  180 
  181         /*
  182          * We use only the kva address for the buffer, but this is extremely
  183          * convenient and fast.
  184          */
  185         bp = uma_zalloc(ncl_pbuf_zone, M_WAITOK);
  186 
  187         kva = (vm_offset_t) bp->b_data;
  188         pmap_qenter(kva, pages, npages);
  189         VM_CNT_INC(v_vnodein);
  190         VM_CNT_ADD(v_vnodepgsin, npages);
  191 
  192         count = npages << PAGE_SHIFT;
  193         iov.iov_base = (caddr_t) kva;
  194         iov.iov_len = count;
  195         uio.uio_iov = &iov;
  196         uio.uio_iovcnt = 1;
  197         uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
  198         uio.uio_resid = count;
  199         uio.uio_segflg = UIO_SYSSPACE;
  200         uio.uio_rw = UIO_READ;
  201         uio.uio_td = td;
  202 
  203         error = ncl_readrpc(vp, &uio, cred);
  204         pmap_qremove(kva, npages);
  205 
  206         uma_zfree(ncl_pbuf_zone, bp);
  207 
  208         if (error && (uio.uio_resid == count)) {
  209                 printf("ncl_getpages: error %d\n", error);
  210                 return (VM_PAGER_ERROR);
  211         }
  212 
  213         /*
  214          * Calculate the number of bytes read and validate only that number
  215          * of bytes.  Note that due to pending writes, size may be 0.  This
  216          * does not mean that the remaining data is invalid!
  217          */
  218 
  219         size = count - uio.uio_resid;
  220         VM_OBJECT_WLOCK(object);
  221         for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
  222                 vm_page_t m;
  223                 nextoff = toff + PAGE_SIZE;
  224                 m = pages[i];
  225 
  226                 if (nextoff <= size) {
  227                         /*
  228                          * Read operation filled an entire page
  229                          */
  230                         m->valid = VM_PAGE_BITS_ALL;
  231                         KASSERT(m->dirty == 0,
  232                             ("nfs_getpages: page %p is dirty", m));
  233                 } else if (size > toff) {
  234                         /*
  235                          * Read operation filled a partial page.
  236                          */
  237                         m->valid = 0;
  238                         vm_page_set_valid_range(m, 0, size - toff);
  239                         KASSERT(m->dirty == 0,
  240                             ("nfs_getpages: page %p is dirty", m));
  241                 } else {
  242                         /*
  243                          * Read operation was short.  If no error
  244                          * occurred we may have hit a zero-fill
  245                          * section.  We leave valid set to 0, and page
  246                          * is freed by vm_page_readahead_finish() if
  247                          * its index is not equal to requested, or
  248                          * page is zeroed and set valid by
  249                          * vm_pager_get_pages() for requested page.
  250                          */
  251                         ;
  252                 }
  253         }
  254 out:
  255         VM_OBJECT_WUNLOCK(object);
  256         if (ap->a_rbehind)
  257                 *ap->a_rbehind = 0;
  258         if (ap->a_rahead)
  259                 *ap->a_rahead = 0;
  260         return (VM_PAGER_OK);
  261 }
  262 
  263 /*
  264  * Vnode op for VM putpages.
  265  */
  266 int
  267 ncl_putpages(struct vop_putpages_args *ap)
  268 {
  269         struct uio uio;
  270         struct iovec iov;
  271         int i, error, npages, count;
  272         off_t offset;
  273         int *rtvals;
  274         struct vnode *vp;
  275         struct thread *td;
  276         struct ucred *cred;
  277         struct nfsmount *nmp;
  278         struct nfsnode *np;
  279         vm_page_t *pages;
  280 
  281         vp = ap->a_vp;
  282         np = VTONFS(vp);
  283         td = curthread;                         /* XXX */
  284         /* Set the cred to n_writecred for the write rpcs. */
  285         if (np->n_writecred != NULL)
  286                 cred = crhold(np->n_writecred);
  287         else
  288                 cred = crhold(curthread->td_ucred);     /* XXX */
  289         nmp = VFSTONFS(vp->v_mount);
  290         pages = ap->a_m;
  291         count = ap->a_count;
  292         rtvals = ap->a_rtvals;
  293         npages = btoc(count);
  294         offset = IDX_TO_OFF(pages[0]->pindex);
  295 
  296         mtx_lock(&nmp->nm_mtx);
  297         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  298             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  299                 mtx_unlock(&nmp->nm_mtx);
  300                 (void)ncl_fsinfo(nmp, vp, cred, td);
  301         } else
  302                 mtx_unlock(&nmp->nm_mtx);
  303 
  304         mtx_lock(&np->n_mtx);
  305         if (newnfs_directio_enable && !newnfs_directio_allow_mmap &&
  306             (np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
  307                 mtx_unlock(&np->n_mtx);
  308                 printf("ncl_putpages: called on noncache-able vnode\n");
  309                 mtx_lock(&np->n_mtx);
  310         }
  311         /*
  312          * When putting pages, do not extend file past EOF.
  313          */
  314         if (offset + count > np->n_size) {
  315                 count = np->n_size - offset;
  316                 if (count < 0)
  317                         count = 0;
  318         }
  319         mtx_unlock(&np->n_mtx);
  320 
  321         for (i = 0; i < npages; i++)
  322                 rtvals[i] = VM_PAGER_ERROR;
  323 
  324         VM_CNT_INC(v_vnodeout);
  325         VM_CNT_ADD(v_vnodepgsout, count);
  326 
  327         iov.iov_base = unmapped_buf;
  328         iov.iov_len = count;
  329         uio.uio_iov = &iov;
  330         uio.uio_iovcnt = 1;
  331         uio.uio_offset = offset;
  332         uio.uio_resid = count;
  333         uio.uio_segflg = UIO_NOCOPY;
  334         uio.uio_rw = UIO_WRITE;
  335         uio.uio_td = td;
  336 
  337         error = VOP_WRITE(vp, &uio, vnode_pager_putpages_ioflags(ap->a_sync),
  338             cred);
  339         crfree(cred);
  340 
  341         if (error == 0 || !nfs_keep_dirty_on_error) {
  342                 vnode_pager_undirty_pages(pages, rtvals, count - uio.uio_resid,
  343                     np->n_size - offset, npages * PAGE_SIZE);
  344         }
  345         return (rtvals[0]);
  346 }
  347 
  348 /*
  349  * For nfs, cache consistency can only be maintained approximately.
  350  * Although RFC1094 does not specify the criteria, the following is
  351  * believed to be compatible with the reference port.
  352  * For nfs:
  353  * If the file's modify time on the server has changed since the
  354  * last read rpc or you have written to the file,
  355  * you may have lost data cache consistency with the
  356  * server, so flush all of the file's data out of the cache.
  357  * Then force a getattr rpc to ensure that you have up to date
  358  * attributes.
  359  * NB: This implies that cache data can be read when up to
  360  * NFS_ATTRTIMEO seconds out of date. If you find that you need current
  361  * attributes this could be forced by setting n_attrstamp to 0 before
  362  * the VOP_GETATTR() call.
  363  */
  364 static inline int
  365 nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
  366 {
  367         int error = 0;
  368         struct vattr vattr;
  369         struct nfsnode *np = VTONFS(vp);
  370         bool old_lock;
  371 
  372         /*
  373          * Ensure the exclusove access to the node before checking
  374          * whether the cache is consistent.
  375          */
  376         old_lock = ncl_excl_start(vp);
  377         mtx_lock(&np->n_mtx);
  378         if (np->n_flag & NMODIFIED) {
  379                 mtx_unlock(&np->n_mtx);
  380                 if (vp->v_type != VREG) {
  381                         if (vp->v_type != VDIR)
  382                                 panic("nfs: bioread, not dir");
  383                         ncl_invaldir(vp);
  384                         error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
  385                         if (error != 0)
  386                                 goto out;
  387                 }
  388                 np->n_attrstamp = 0;
  389                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  390                 error = VOP_GETATTR(vp, &vattr, cred);
  391                 if (error)
  392                         goto out;
  393                 mtx_lock(&np->n_mtx);
  394                 np->n_mtime = vattr.va_mtime;
  395                 mtx_unlock(&np->n_mtx);
  396         } else {
  397                 mtx_unlock(&np->n_mtx);
  398                 error = VOP_GETATTR(vp, &vattr, cred);
  399                 if (error)
  400                         goto out;
  401                 mtx_lock(&np->n_mtx);
  402                 if ((np->n_flag & NSIZECHANGED)
  403                     || (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
  404                         mtx_unlock(&np->n_mtx);
  405                         if (vp->v_type == VDIR)
  406                                 ncl_invaldir(vp);
  407                         error = ncl_vinvalbuf(vp, V_SAVE | V_ALLOWCLEAN, td, 1);
  408                         if (error != 0)
  409                                 goto out;
  410                         mtx_lock(&np->n_mtx);
  411                         np->n_mtime = vattr.va_mtime;
  412                         np->n_flag &= ~NSIZECHANGED;
  413                 }
  414                 mtx_unlock(&np->n_mtx);
  415         }
  416 out:
  417         ncl_excl_finish(vp, old_lock);
  418         return (error);
  419 }
  420 
  421 /*
  422  * Vnode op for read using bio
  423  */
  424 int
  425 ncl_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
  426 {
  427         struct nfsnode *np = VTONFS(vp);
  428         int biosize, i;
  429         struct buf *bp, *rabp;
  430         struct thread *td;
  431         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  432         daddr_t lbn, rabn;
  433         int bcount;
  434         int seqcount;
  435         int nra, error = 0, n = 0, on = 0;
  436         off_t tmp_off;
  437 
  438         KASSERT(uio->uio_rw == UIO_READ, ("ncl_read mode"));
  439         if (uio->uio_resid == 0)
  440                 return (0);
  441         if (uio->uio_offset < 0)        /* XXX VDIR cookies can be negative */
  442                 return (EINVAL);
  443         td = uio->uio_td;
  444 
  445         mtx_lock(&nmp->nm_mtx);
  446         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  447             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  448                 mtx_unlock(&nmp->nm_mtx);
  449                 (void)ncl_fsinfo(nmp, vp, cred, td);
  450                 mtx_lock(&nmp->nm_mtx);
  451         }
  452         if (nmp->nm_rsize == 0 || nmp->nm_readdirsize == 0)
  453                 (void) newnfs_iosize(nmp);
  454 
  455         tmp_off = uio->uio_offset + uio->uio_resid;
  456         if (vp->v_type != VDIR &&
  457             (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)) {
  458                 mtx_unlock(&nmp->nm_mtx);
  459                 return (EFBIG);
  460         }
  461         mtx_unlock(&nmp->nm_mtx);
  462 
  463         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
  464                 /* No caching/ no readaheads. Just read data into the user buffer */
  465                 return ncl_readrpc(vp, uio, cred);
  466 
  467         biosize = vp->v_bufobj.bo_bsize;
  468         seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
  469 
  470         error = nfs_bioread_check_cons(vp, td, cred);
  471         if (error)
  472                 return error;
  473 
  474         do {
  475             u_quad_t nsize;
  476 
  477             mtx_lock(&np->n_mtx);
  478             nsize = np->n_size;
  479             mtx_unlock(&np->n_mtx);
  480 
  481             switch (vp->v_type) {
  482             case VREG:
  483                 NFSINCRGLOBAL(nfsstatsv1.biocache_reads);
  484                 lbn = uio->uio_offset / biosize;
  485                 on = uio->uio_offset - (lbn * biosize);
  486 
  487                 /*
  488                  * Start the read ahead(s), as required.
  489                  */
  490                 if (nmp->nm_readahead > 0) {
  491                     for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
  492                         (off_t)(lbn + 1 + nra) * biosize < nsize; nra++) {
  493                         rabn = lbn + 1 + nra;
  494                         if (incore(&vp->v_bufobj, rabn) == NULL) {
  495                             rabp = nfs_getcacheblk(vp, rabn, biosize, td);
  496                             if (!rabp) {
  497                                 error = newnfs_sigintr(nmp, td);
  498                                 return (error ? error : EINTR);
  499                             }
  500                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  501                                 rabp->b_flags |= B_ASYNC;
  502                                 rabp->b_iocmd = BIO_READ;
  503                                 vfs_busy_pages(rabp, 0);
  504                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  505                                     rabp->b_flags |= B_INVAL;
  506                                     rabp->b_ioflags |= BIO_ERROR;
  507                                     vfs_unbusy_pages(rabp);
  508                                     brelse(rabp);
  509                                     break;
  510                                 }
  511                             } else {
  512                                 brelse(rabp);
  513                             }
  514                         }
  515                     }
  516                 }
  517 
  518                 /* Note that bcount is *not* DEV_BSIZE aligned. */
  519                 bcount = biosize;
  520                 if ((off_t)lbn * biosize >= nsize) {
  521                         bcount = 0;
  522                 } else if ((off_t)(lbn + 1) * biosize > nsize) {
  523                         bcount = nsize - (off_t)lbn * biosize;
  524                 }
  525                 bp = nfs_getcacheblk(vp, lbn, bcount, td);
  526 
  527                 if (!bp) {
  528                         error = newnfs_sigintr(nmp, td);
  529                         return (error ? error : EINTR);
  530                 }
  531 
  532                 /*
  533                  * If B_CACHE is not set, we must issue the read.  If this
  534                  * fails, we return an error.
  535                  */
  536 
  537                 if ((bp->b_flags & B_CACHE) == 0) {
  538                     bp->b_iocmd = BIO_READ;
  539                     vfs_busy_pages(bp, 0);
  540                     error = ncl_doio(vp, bp, cred, td, 0);
  541                     if (error) {
  542                         brelse(bp);
  543                         return (error);
  544                     }
  545                 }
  546 
  547                 /*
  548                  * on is the offset into the current bp.  Figure out how many
  549                  * bytes we can copy out of the bp.  Note that bcount is
  550                  * NOT DEV_BSIZE aligned.
  551                  *
  552                  * Then figure out how many bytes we can copy into the uio.
  553                  */
  554 
  555                 n = 0;
  556                 if (on < bcount)
  557                         n = MIN((unsigned)(bcount - on), uio->uio_resid);
  558                 break;
  559             case VLNK:
  560                 NFSINCRGLOBAL(nfsstatsv1.biocache_readlinks);
  561                 bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
  562                 if (!bp) {
  563                         error = newnfs_sigintr(nmp, td);
  564                         return (error ? error : EINTR);
  565                 }
  566                 if ((bp->b_flags & B_CACHE) == 0) {
  567                     bp->b_iocmd = BIO_READ;
  568                     vfs_busy_pages(bp, 0);
  569                     error = ncl_doio(vp, bp, cred, td, 0);
  570                     if (error) {
  571                         bp->b_ioflags |= BIO_ERROR;
  572                         brelse(bp);
  573                         return (error);
  574                     }
  575                 }
  576                 n = MIN(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
  577                 on = 0;
  578                 break;
  579             case VDIR:
  580                 NFSINCRGLOBAL(nfsstatsv1.biocache_readdirs);
  581                 if (np->n_direofoffset
  582                     && uio->uio_offset >= np->n_direofoffset) {
  583                     return (0);
  584                 }
  585                 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
  586                 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
  587                 bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
  588                 if (!bp) {
  589                     error = newnfs_sigintr(nmp, td);
  590                     return (error ? error : EINTR);
  591                 }
  592                 if ((bp->b_flags & B_CACHE) == 0) {
  593                     bp->b_iocmd = BIO_READ;
  594                     vfs_busy_pages(bp, 0);
  595                     error = ncl_doio(vp, bp, cred, td, 0);
  596                     if (error) {
  597                             brelse(bp);
  598                     }
  599                     while (error == NFSERR_BAD_COOKIE) {
  600                         ncl_invaldir(vp);
  601                         error = ncl_vinvalbuf(vp, 0, td, 1);
  602 
  603                         /*
  604                          * Yuck! The directory has been modified on the
  605                          * server. The only way to get the block is by
  606                          * reading from the beginning to get all the
  607                          * offset cookies.
  608                          *
  609                          * Leave the last bp intact unless there is an error.
  610                          * Loop back up to the while if the error is another
  611                          * NFSERR_BAD_COOKIE (double yuch!).
  612                          */
  613                         for (i = 0; i <= lbn && !error; i++) {
  614                             if (np->n_direofoffset
  615                                 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
  616                                     return (0);
  617                             bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
  618                             if (!bp) {
  619                                 error = newnfs_sigintr(nmp, td);
  620                                 return (error ? error : EINTR);
  621                             }
  622                             if ((bp->b_flags & B_CACHE) == 0) {
  623                                     bp->b_iocmd = BIO_READ;
  624                                     vfs_busy_pages(bp, 0);
  625                                     error = ncl_doio(vp, bp, cred, td, 0);
  626                                     /*
  627                                      * no error + B_INVAL == directory EOF,
  628                                      * use the block.
  629                                      */
  630                                     if (error == 0 && (bp->b_flags & B_INVAL))
  631                                             break;
  632                             }
  633                             /*
  634                              * An error will throw away the block and the
  635                              * for loop will break out.  If no error and this
  636                              * is not the block we want, we throw away the
  637                              * block and go for the next one via the for loop.
  638                              */
  639                             if (error || i < lbn)
  640                                     brelse(bp);
  641                         }
  642                     }
  643                     /*
  644                      * The above while is repeated if we hit another cookie
  645                      * error.  If we hit an error and it wasn't a cookie error,
  646                      * we give up.
  647                      */
  648                     if (error)
  649                             return (error);
  650                 }
  651 
  652                 /*
  653                  * If not eof and read aheads are enabled, start one.
  654                  * (You need the current block first, so that you have the
  655                  *  directory offset cookie of the next block.)
  656                  */
  657                 if (nmp->nm_readahead > 0 &&
  658                     (bp->b_flags & B_INVAL) == 0 &&
  659                     (np->n_direofoffset == 0 ||
  660                     (lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
  661                     incore(&vp->v_bufobj, lbn + 1) == NULL) {
  662                         rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
  663                         if (rabp) {
  664                             if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
  665                                 rabp->b_flags |= B_ASYNC;
  666                                 rabp->b_iocmd = BIO_READ;
  667                                 vfs_busy_pages(rabp, 0);
  668                                 if (ncl_asyncio(nmp, rabp, cred, td)) {
  669                                     rabp->b_flags |= B_INVAL;
  670                                     rabp->b_ioflags |= BIO_ERROR;
  671                                     vfs_unbusy_pages(rabp);
  672                                     brelse(rabp);
  673                                 }
  674                             } else {
  675                                 brelse(rabp);
  676                             }
  677                         }
  678                 }
  679                 /*
  680                  * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
  681                  * chopped for the EOF condition, we cannot tell how large
  682                  * NFS directories are going to be until we hit EOF.  So
  683                  * an NFS directory buffer is *not* chopped to its EOF.  Now,
  684                  * it just so happens that b_resid will effectively chop it
  685                  * to EOF.  *BUT* this information is lost if the buffer goes
  686                  * away and is reconstituted into a B_CACHE state ( due to
  687                  * being VMIO ) later.  So we keep track of the directory eof
  688                  * in np->n_direofoffset and chop it off as an extra step
  689                  * right here.
  690                  */
  691                 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
  692                 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
  693                         n = np->n_direofoffset - uio->uio_offset;
  694                 break;
  695             default:
  696                 printf(" ncl_bioread: type %x unexpected\n", vp->v_type);
  697                 bp = NULL;
  698                 break;
  699             }
  700 
  701             if (n > 0) {
  702                     error = vn_io_fault_uiomove(bp->b_data + on, (int)n, uio);
  703             }
  704             if (vp->v_type == VLNK)
  705                 n = 0;
  706             if (bp != NULL)
  707                 brelse(bp);
  708         } while (error == 0 && uio->uio_resid > 0 && n > 0);
  709         return (error);
  710 }
  711 
  712 /*
  713  * The NFS write path cannot handle iovecs with len > 1. So we need to
  714  * break up iovecs accordingly (restricting them to wsize).
  715  * For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
  716  * For the ASYNC case, 2 copies are needed. The first a copy from the
  717  * user buffer to a staging buffer and then a second copy from the staging
  718  * buffer to mbufs. This can be optimized by copying from the user buffer
  719  * directly into mbufs and passing the chain down, but that requires a
  720  * fair amount of re-working of the relevant codepaths (and can be done
  721  * later).
  722  */
  723 static int
  724 nfs_directio_write(vp, uiop, cred, ioflag)
  725         struct vnode *vp;
  726         struct uio *uiop;
  727         struct ucred *cred;
  728         int ioflag;
  729 {
  730         int error;
  731         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  732         struct thread *td = uiop->uio_td;
  733         int size;
  734         int wsize;
  735 
  736         mtx_lock(&nmp->nm_mtx);
  737         wsize = nmp->nm_wsize;
  738         mtx_unlock(&nmp->nm_mtx);
  739         if (ioflag & IO_SYNC) {
  740                 int iomode, must_commit;
  741                 struct uio uio;
  742                 struct iovec iov;
  743 do_sync:
  744                 while (uiop->uio_resid > 0) {
  745                         size = MIN(uiop->uio_resid, wsize);
  746                         size = MIN(uiop->uio_iov->iov_len, size);
  747                         iov.iov_base = uiop->uio_iov->iov_base;
  748                         iov.iov_len = size;
  749                         uio.uio_iov = &iov;
  750                         uio.uio_iovcnt = 1;
  751                         uio.uio_offset = uiop->uio_offset;
  752                         uio.uio_resid = size;
  753                         uio.uio_segflg = UIO_USERSPACE;
  754                         uio.uio_rw = UIO_WRITE;
  755                         uio.uio_td = td;
  756                         iomode = NFSWRITE_FILESYNC;
  757                         error = ncl_writerpc(vp, &uio, cred, &iomode,
  758                             &must_commit, 0);
  759                         KASSERT((must_commit == 0),
  760                                 ("ncl_directio_write: Did not commit write"));
  761                         if (error)
  762                                 return (error);
  763                         uiop->uio_offset += size;
  764                         uiop->uio_resid -= size;
  765                         if (uiop->uio_iov->iov_len <= size) {
  766                                 uiop->uio_iovcnt--;
  767                                 uiop->uio_iov++;
  768                         } else {
  769                                 uiop->uio_iov->iov_base =
  770                                         (char *)uiop->uio_iov->iov_base + size;
  771                                 uiop->uio_iov->iov_len -= size;
  772                         }
  773                 }
  774         } else {
  775                 struct uio *t_uio;
  776                 struct iovec *t_iov;
  777                 struct buf *bp;
  778 
  779                 /*
  780                  * Break up the write into blocksize chunks and hand these
  781                  * over to nfsiod's for write back.
  782                  * Unfortunately, this incurs a copy of the data. Since
  783                  * the user could modify the buffer before the write is
  784                  * initiated.
  785                  *
  786                  * The obvious optimization here is that one of the 2 copies
  787                  * in the async write path can be eliminated by copying the
  788                  * data here directly into mbufs and passing the mbuf chain
  789                  * down. But that will require a fair amount of re-working
  790                  * of the code and can be done if there's enough interest
  791                  * in NFS directio access.
  792                  */
  793                 while (uiop->uio_resid > 0) {
  794                         size = MIN(uiop->uio_resid, wsize);
  795                         size = MIN(uiop->uio_iov->iov_len, size);
  796                         bp = uma_zalloc(ncl_pbuf_zone, M_WAITOK);
  797                         t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
  798                         t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
  799                         t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
  800                         t_iov->iov_len = size;
  801                         t_uio->uio_iov = t_iov;
  802                         t_uio->uio_iovcnt = 1;
  803                         t_uio->uio_offset = uiop->uio_offset;
  804                         t_uio->uio_resid = size;
  805                         t_uio->uio_segflg = UIO_SYSSPACE;
  806                         t_uio->uio_rw = UIO_WRITE;
  807                         t_uio->uio_td = td;
  808                         KASSERT(uiop->uio_segflg == UIO_USERSPACE ||
  809                             uiop->uio_segflg == UIO_SYSSPACE,
  810                             ("nfs_directio_write: Bad uio_segflg"));
  811                         if (uiop->uio_segflg == UIO_USERSPACE) {
  812                                 error = copyin(uiop->uio_iov->iov_base,
  813                                     t_iov->iov_base, size);
  814                                 if (error != 0)
  815                                         goto err_free;
  816                         } else
  817                                 /*
  818                                  * UIO_SYSSPACE may never happen, but handle
  819                                  * it just in case it does.
  820                                  */
  821                                 bcopy(uiop->uio_iov->iov_base, t_iov->iov_base,
  822                                     size);
  823                         bp->b_flags |= B_DIRECT;
  824                         bp->b_iocmd = BIO_WRITE;
  825                         if (cred != NOCRED) {
  826                                 crhold(cred);
  827                                 bp->b_wcred = cred;
  828                         } else
  829                                 bp->b_wcred = NOCRED;
  830                         bp->b_caller1 = (void *)t_uio;
  831                         bp->b_vp = vp;
  832                         error = ncl_asyncio(nmp, bp, NOCRED, td);
  833 err_free:
  834                         if (error) {
  835                                 free(t_iov->iov_base, M_NFSDIRECTIO);
  836                                 free(t_iov, M_NFSDIRECTIO);
  837                                 free(t_uio, M_NFSDIRECTIO);
  838                                 bp->b_vp = NULL;
  839                                 uma_zfree(ncl_pbuf_zone, bp);
  840                                 if (error == EINTR)
  841                                         return (error);
  842                                 goto do_sync;
  843                         }
  844                         uiop->uio_offset += size;
  845                         uiop->uio_resid -= size;
  846                         if (uiop->uio_iov->iov_len <= size) {
  847                                 uiop->uio_iovcnt--;
  848                                 uiop->uio_iov++;
  849                         } else {
  850                                 uiop->uio_iov->iov_base =
  851                                         (char *)uiop->uio_iov->iov_base + size;
  852                                 uiop->uio_iov->iov_len -= size;
  853                         }
  854                 }
  855         }
  856         return (0);
  857 }
  858 
  859 /*
  860  * Vnode op for write using bio
  861  */
  862 int
  863 ncl_write(struct vop_write_args *ap)
  864 {
  865         int biosize;
  866         struct uio *uio = ap->a_uio;
  867         struct thread *td = uio->uio_td;
  868         struct vnode *vp = ap->a_vp;
  869         struct nfsnode *np = VTONFS(vp);
  870         struct ucred *cred = ap->a_cred;
  871         int ioflag = ap->a_ioflag;
  872         struct buf *bp;
  873         struct vattr vattr;
  874         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
  875         daddr_t lbn;
  876         int bcount, noncontig_write, obcount;
  877         int bp_cached, n, on, error = 0, error1, wouldcommit;
  878         size_t orig_resid, local_resid;
  879         off_t orig_size, tmp_off;
  880 
  881         KASSERT(uio->uio_rw == UIO_WRITE, ("ncl_write mode"));
  882         KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
  883             ("ncl_write proc"));
  884         if (vp->v_type != VREG)
  885                 return (EIO);
  886         mtx_lock(&np->n_mtx);
  887         if (np->n_flag & NWRITEERR) {
  888                 np->n_flag &= ~NWRITEERR;
  889                 mtx_unlock(&np->n_mtx);
  890                 return (np->n_error);
  891         } else
  892                 mtx_unlock(&np->n_mtx);
  893         mtx_lock(&nmp->nm_mtx);
  894         if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
  895             (nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
  896                 mtx_unlock(&nmp->nm_mtx);
  897                 (void)ncl_fsinfo(nmp, vp, cred, td);
  898                 mtx_lock(&nmp->nm_mtx);
  899         }
  900         if (nmp->nm_wsize == 0)
  901                 (void) newnfs_iosize(nmp);
  902         mtx_unlock(&nmp->nm_mtx);
  903 
  904         /*
  905          * Synchronously flush pending buffers if we are in synchronous
  906          * mode or if we are appending.
  907          */
  908         if (ioflag & (IO_APPEND | IO_SYNC)) {
  909                 mtx_lock(&np->n_mtx);
  910                 if (np->n_flag & NMODIFIED) {
  911                         mtx_unlock(&np->n_mtx);
  912 #ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
  913                         /*
  914                          * Require non-blocking, synchronous writes to
  915                          * dirty files to inform the program it needs
  916                          * to fsync(2) explicitly.
  917                          */
  918                         if (ioflag & IO_NDELAY)
  919                                 return (EAGAIN);
  920 #endif
  921                         np->n_attrstamp = 0;
  922                         KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  923                         error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
  924                             IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
  925                         if (error != 0)
  926                                 return (error);
  927                 } else
  928                         mtx_unlock(&np->n_mtx);
  929         }
  930 
  931         orig_resid = uio->uio_resid;
  932         mtx_lock(&np->n_mtx);
  933         orig_size = np->n_size;
  934         mtx_unlock(&np->n_mtx);
  935 
  936         /*
  937          * If IO_APPEND then load uio_offset.  We restart here if we cannot
  938          * get the append lock.
  939          */
  940         if (ioflag & IO_APPEND) {
  941                 np->n_attrstamp = 0;
  942                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
  943                 error = VOP_GETATTR(vp, &vattr, cred);
  944                 if (error)
  945                         return (error);
  946                 mtx_lock(&np->n_mtx);
  947                 uio->uio_offset = np->n_size;
  948                 mtx_unlock(&np->n_mtx);
  949         }
  950 
  951         if (uio->uio_offset < 0)
  952                 return (EINVAL);
  953         tmp_off = uio->uio_offset + uio->uio_resid;
  954         if (tmp_off > nmp->nm_maxfilesize || tmp_off < uio->uio_offset)
  955                 return (EFBIG);
  956         if (uio->uio_resid == 0)
  957                 return (0);
  958 
  959         if (newnfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
  960                 return nfs_directio_write(vp, uio, cred, ioflag);
  961 
  962         /*
  963          * Maybe this should be above the vnode op call, but so long as
  964          * file servers have no limits, i don't think it matters
  965          */
  966         if (vn_rlimit_fsize(vp, uio, td))
  967                 return (EFBIG);
  968 
  969         biosize = vp->v_bufobj.bo_bsize;
  970         /*
  971          * Find all of this file's B_NEEDCOMMIT buffers.  If our writes
  972          * would exceed the local maximum per-file write commit size when
  973          * combined with those, we must decide whether to flush,
  974          * go synchronous, or return error.  We don't bother checking
  975          * IO_UNIT -- we just make all writes atomic anyway, as there's
  976          * no point optimizing for something that really won't ever happen.
  977          */
  978         wouldcommit = 0;
  979         if (!(ioflag & IO_SYNC)) {
  980                 int nflag;
  981 
  982                 mtx_lock(&np->n_mtx);
  983                 nflag = np->n_flag;
  984                 mtx_unlock(&np->n_mtx);
  985                 if (nflag & NMODIFIED) {
  986                         BO_LOCK(&vp->v_bufobj);
  987                         if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
  988                                 TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
  989                                     b_bobufs) {
  990                                         if (bp->b_flags & B_NEEDCOMMIT)
  991                                                 wouldcommit += bp->b_bcount;
  992                                 }
  993                         }
  994                         BO_UNLOCK(&vp->v_bufobj);
  995                 }
  996         }
  997 
  998         do {
  999                 if (!(ioflag & IO_SYNC)) {
 1000                         wouldcommit += biosize;
 1001                         if (wouldcommit > nmp->nm_wcommitsize) {
 1002                                 np->n_attrstamp = 0;
 1003                                 KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
 1004                                 error = ncl_vinvalbuf(vp, V_SAVE | ((ioflag &
 1005                                     IO_VMIO) != 0 ? V_VMIO : 0), td, 1);
 1006                                 if (error != 0)
 1007                                         return (error);
 1008                                 wouldcommit = biosize;
 1009                         }
 1010                 }
 1011 
 1012                 NFSINCRGLOBAL(nfsstatsv1.biocache_writes);
 1013                 lbn = uio->uio_offset / biosize;
 1014                 on = uio->uio_offset - (lbn * biosize);
 1015                 n = MIN((unsigned)(biosize - on), uio->uio_resid);
 1016 again:
 1017                 /*
 1018                  * Handle direct append and file extension cases, calculate
 1019                  * unaligned buffer size.
 1020                  */
 1021                 mtx_lock(&np->n_mtx);
 1022                 if ((np->n_flag & NHASBEENLOCKED) == 0 &&
 1023                     (nmp->nm_flag & NFSMNT_NONCONTIGWR) != 0)
 1024                         noncontig_write = 1;
 1025                 else
 1026                         noncontig_write = 0;
 1027                 if ((uio->uio_offset == np->n_size ||
 1028                     (noncontig_write != 0 &&
 1029                     lbn == (np->n_size / biosize) &&
 1030                     uio->uio_offset + n > np->n_size)) && n) {
 1031                         mtx_unlock(&np->n_mtx);
 1032                         /*
 1033                          * Get the buffer (in its pre-append state to maintain
 1034                          * B_CACHE if it was previously set).  Resize the
 1035                          * nfsnode after we have locked the buffer to prevent
 1036                          * readers from reading garbage.
 1037                          */
 1038                         obcount = np->n_size - (lbn * biosize);
 1039                         bp = nfs_getcacheblk(vp, lbn, obcount, td);
 1040 
 1041                         if (bp != NULL) {
 1042                                 long save;
 1043 
 1044                                 mtx_lock(&np->n_mtx);
 1045                                 np->n_size = uio->uio_offset + n;
 1046                                 np->n_flag |= NMODIFIED;
 1047                                 vnode_pager_setsize(vp, np->n_size);
 1048                                 mtx_unlock(&np->n_mtx);
 1049 
 1050                                 save = bp->b_flags & B_CACHE;
 1051                                 bcount = on + n;
 1052                                 allocbuf(bp, bcount);
 1053                                 bp->b_flags |= save;
 1054                                 if (noncontig_write != 0 && on > obcount)
 1055                                         vfs_bio_bzero_buf(bp, obcount, on -
 1056                                             obcount);
 1057                         }
 1058                 } else {
 1059                         /*
 1060                          * Obtain the locked cache block first, and then
 1061                          * adjust the file's size as appropriate.
 1062                          */
 1063                         bcount = on + n;
 1064                         if ((off_t)lbn * biosize + bcount < np->n_size) {
 1065                                 if ((off_t)(lbn + 1) * biosize < np->n_size)
 1066                                         bcount = biosize;
 1067                                 else
 1068                                         bcount = np->n_size - (off_t)lbn * biosize;
 1069                         }
 1070                         mtx_unlock(&np->n_mtx);
 1071                         bp = nfs_getcacheblk(vp, lbn, bcount, td);
 1072                         mtx_lock(&np->n_mtx);
 1073                         if (uio->uio_offset + n > np->n_size) {
 1074                                 np->n_size = uio->uio_offset + n;
 1075                                 np->n_flag |= NMODIFIED;
 1076                                 vnode_pager_setsize(vp, np->n_size);
 1077                         }
 1078                         mtx_unlock(&np->n_mtx);
 1079                 }
 1080 
 1081                 if (!bp) {
 1082                         error = newnfs_sigintr(nmp, td);
 1083                         if (!error)
 1084                                 error = EINTR;
 1085                         break;
 1086                 }
 1087 
 1088                 /*
 1089                  * Issue a READ if B_CACHE is not set.  In special-append
 1090                  * mode, B_CACHE is based on the buffer prior to the write
 1091                  * op and is typically set, avoiding the read.  If a read
 1092                  * is required in special append mode, the server will
 1093                  * probably send us a short-read since we extended the file
 1094                  * on our end, resulting in b_resid == 0 and, thusly,
 1095                  * B_CACHE getting set.
 1096                  *
 1097                  * We can also avoid issuing the read if the write covers
 1098                  * the entire buffer.  We have to make sure the buffer state
 1099                  * is reasonable in this case since we will not be initiating
 1100                  * I/O.  See the comments in kern/vfs_bio.c's getblk() for
 1101                  * more information.
 1102                  *
 1103                  * B_CACHE may also be set due to the buffer being cached
 1104                  * normally.
 1105                  */
 1106 
 1107                 bp_cached = 1;
 1108                 if (on == 0 && n == bcount) {
 1109                         if ((bp->b_flags & B_CACHE) == 0)
 1110                                 bp_cached = 0;
 1111                         bp->b_flags |= B_CACHE;
 1112                         bp->b_flags &= ~B_INVAL;
 1113                         bp->b_ioflags &= ~BIO_ERROR;
 1114                 }
 1115 
 1116                 if ((bp->b_flags & B_CACHE) == 0) {
 1117                         bp->b_iocmd = BIO_READ;
 1118                         vfs_busy_pages(bp, 0);
 1119                         error = ncl_doio(vp, bp, cred, td, 0);
 1120                         if (error) {
 1121                                 brelse(bp);
 1122                                 break;
 1123                         }
 1124                 }
 1125                 if (bp->b_wcred == NOCRED)
 1126                         bp->b_wcred = crhold(cred);
 1127                 mtx_lock(&np->n_mtx);
 1128                 np->n_flag |= NMODIFIED;
 1129                 mtx_unlock(&np->n_mtx);
 1130 
 1131                 /*
 1132                  * If dirtyend exceeds file size, chop it down.  This should
 1133                  * not normally occur but there is an append race where it
 1134                  * might occur XXX, so we log it.
 1135                  *
 1136                  * If the chopping creates a reverse-indexed or degenerate
 1137                  * situation with dirtyoff/end, we 0 both of them.
 1138                  */
 1139 
 1140                 if (bp->b_dirtyend > bcount) {
 1141                         printf("NFS append race @%lx:%d\n",
 1142                             (long)bp->b_blkno * DEV_BSIZE,
 1143                             bp->b_dirtyend - bcount);
 1144                         bp->b_dirtyend = bcount;
 1145                 }
 1146 
 1147                 if (bp->b_dirtyoff >= bp->b_dirtyend)
 1148                         bp->b_dirtyoff = bp->b_dirtyend = 0;
 1149 
 1150                 /*
 1151                  * If the new write will leave a contiguous dirty
 1152                  * area, just update the b_dirtyoff and b_dirtyend,
 1153                  * otherwise force a write rpc of the old dirty area.
 1154                  *
 1155                  * If there has been a file lock applied to this file
 1156                  * or vfs.nfs.old_noncontig_writing is set, do the following:
 1157                  * While it is possible to merge discontiguous writes due to
 1158                  * our having a B_CACHE buffer ( and thus valid read data
 1159                  * for the hole), we don't because it could lead to
 1160                  * significant cache coherency problems with multiple clients,
 1161                  * especially if locking is implemented later on.
 1162                  *
 1163                  * If vfs.nfs.old_noncontig_writing is not set and there has
 1164                  * not been file locking done on this file:
 1165                  * Relax coherency a bit for the sake of performance and
 1166                  * expand the current dirty region to contain the new
 1167                  * write even if it means we mark some non-dirty data as
 1168                  * dirty.
 1169                  */
 1170 
 1171                 if (noncontig_write == 0 && bp->b_dirtyend > 0 &&
 1172                     (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
 1173                         if (bwrite(bp) == EINTR) {
 1174                                 error = EINTR;
 1175                                 break;
 1176                         }
 1177                         goto again;
 1178                 }
 1179 
 1180                 local_resid = uio->uio_resid;
 1181                 error = vn_io_fault_uiomove((char *)bp->b_data + on, n, uio);
 1182 
 1183                 if (error != 0 && !bp_cached) {
 1184                         /*
 1185                          * This block has no other content then what
 1186                          * possibly was written by the faulty uiomove.
 1187                          * Release it, forgetting the data pages, to
 1188                          * prevent the leak of uninitialized data to
 1189                          * usermode.
 1190                          */
 1191                         bp->b_ioflags |= BIO_ERROR;
 1192                         brelse(bp);
 1193                         uio->uio_offset -= local_resid - uio->uio_resid;
 1194                         uio->uio_resid = local_resid;
 1195                         break;
 1196                 }
 1197 
 1198                 /*
 1199                  * Since this block is being modified, it must be written
 1200                  * again and not just committed.  Since write clustering does
 1201                  * not work for the stage 1 data write, only the stage 2
 1202                  * commit rpc, we have to clear B_CLUSTEROK as well.
 1203                  */
 1204                 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1205 
 1206                 /*
 1207                  * Get the partial update on the progress made from
 1208                  * uiomove, if an error occurred.
 1209                  */
 1210                 if (error != 0)
 1211                         n = local_resid - uio->uio_resid;
 1212 
 1213                 /*
 1214                  * Only update dirtyoff/dirtyend if not a degenerate
 1215                  * condition.
 1216                  */
 1217                 if (n > 0) {
 1218                         if (bp->b_dirtyend > 0) {
 1219                                 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
 1220                                 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
 1221                         } else {
 1222                                 bp->b_dirtyoff = on;
 1223                                 bp->b_dirtyend = on + n;
 1224                         }
 1225                         vfs_bio_set_valid(bp, on, n);
 1226                 }
 1227 
 1228                 /*
 1229                  * If IO_SYNC do bwrite().
 1230                  *
 1231                  * IO_INVAL appears to be unused.  The idea appears to be
 1232                  * to turn off caching in this case.  Very odd.  XXX
 1233                  */
 1234                 if ((ioflag & IO_SYNC)) {
 1235                         if (ioflag & IO_INVAL)
 1236                                 bp->b_flags |= B_NOCACHE;
 1237                         error1 = bwrite(bp);
 1238                         if (error1 != 0) {
 1239                                 if (error == 0)
 1240                                         error = error1;
 1241                                 break;
 1242                         }
 1243                 } else if ((n + on) == biosize || (ioflag & IO_ASYNC) != 0) {
 1244                         bp->b_flags |= B_ASYNC;
 1245                         (void) ncl_writebp(bp, 0, NULL);
 1246                 } else {
 1247                         bdwrite(bp);
 1248                 }
 1249 
 1250                 if (error != 0)
 1251                         break;
 1252         } while (uio->uio_resid > 0 && n > 0);
 1253 
 1254         if (error != 0) {
 1255                 if (ioflag & IO_UNIT) {
 1256                         VATTR_NULL(&vattr);
 1257                         vattr.va_size = orig_size;
 1258                         /* IO_SYNC is handled implicitely */
 1259                         (void)VOP_SETATTR(vp, &vattr, cred);
 1260                         uio->uio_offset -= orig_resid - uio->uio_resid;
 1261                         uio->uio_resid = orig_resid;
 1262                 }
 1263         }
 1264 
 1265         return (error);
 1266 }
 1267 
 1268 /*
 1269  * Get an nfs cache block.
 1270  *
 1271  * Allocate a new one if the block isn't currently in the cache
 1272  * and return the block marked busy. If the calling process is
 1273  * interrupted by a signal for an interruptible mount point, return
 1274  * NULL.
 1275  *
 1276  * The caller must carefully deal with the possible B_INVAL state of
 1277  * the buffer.  ncl_doio() clears B_INVAL (and ncl_asyncio() clears it
 1278  * indirectly), so synchronous reads can be issued without worrying about
 1279  * the B_INVAL state.  We have to be a little more careful when dealing
 1280  * with writes (see comments in nfs_write()) when extending a file past
 1281  * its EOF.
 1282  */
 1283 static struct buf *
 1284 nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
 1285 {
 1286         struct buf *bp;
 1287         struct mount *mp;
 1288         struct nfsmount *nmp;
 1289 
 1290         mp = vp->v_mount;
 1291         nmp = VFSTONFS(mp);
 1292 
 1293         if (nmp->nm_flag & NFSMNT_INT) {
 1294                 sigset_t oldset;
 1295 
 1296                 newnfs_set_sigmask(td, &oldset);
 1297                 bp = getblk(vp, bn, size, PCATCH, 0, 0);
 1298                 newnfs_restore_sigmask(td, &oldset);
 1299                 while (bp == NULL) {
 1300                         if (newnfs_sigintr(nmp, td))
 1301                                 return (NULL);
 1302                         bp = getblk(vp, bn, size, 0, 2 * hz, 0);
 1303                 }
 1304         } else {
 1305                 bp = getblk(vp, bn, size, 0, 0, 0);
 1306         }
 1307 
 1308         if (vp->v_type == VREG)
 1309                 bp->b_blkno = bn * (vp->v_bufobj.bo_bsize / DEV_BSIZE);
 1310         return (bp);
 1311 }
 1312 
 1313 /*
 1314  * Flush and invalidate all dirty buffers. If another process is already
 1315  * doing the flush, just wait for completion.
 1316  */
 1317 int
 1318 ncl_vinvalbuf(struct vnode *vp, int flags, struct thread *td, int intrflg)
 1319 {
 1320         struct nfsnode *np = VTONFS(vp);
 1321         struct nfsmount *nmp = VFSTONFS(vp->v_mount);
 1322         int error = 0, slpflag, slptimeo;
 1323         bool old_lock;
 1324 
 1325         ASSERT_VOP_LOCKED(vp, "ncl_vinvalbuf");
 1326 
 1327         if ((nmp->nm_flag & NFSMNT_INT) == 0)
 1328                 intrflg = 0;
 1329         if (NFSCL_FORCEDISM(nmp->nm_mountp))
 1330                 intrflg = 1;
 1331         if (intrflg) {
 1332                 slpflag = PCATCH;
 1333                 slptimeo = 2 * hz;
 1334         } else {
 1335                 slpflag = 0;
 1336                 slptimeo = 0;
 1337         }
 1338 
 1339         old_lock = ncl_excl_start(vp);
 1340         if (old_lock)
 1341                 flags |= V_ALLOWCLEAN;
 1342 
 1343         /*
 1344          * Now, flush as required.
 1345          */
 1346         if ((flags & (V_SAVE | V_VMIO)) == V_SAVE &&
 1347              vp->v_bufobj.bo_object != NULL) {
 1348                 VM_OBJECT_WLOCK(vp->v_bufobj.bo_object);
 1349                 vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
 1350                 VM_OBJECT_WUNLOCK(vp->v_bufobj.bo_object);
 1351                 /*
 1352                  * If the page clean was interrupted, fail the invalidation.
 1353                  * Not doing so, we run the risk of losing dirty pages in the
 1354                  * vinvalbuf() call below.
 1355                  */
 1356                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1357                         goto out;
 1358         }
 1359 
 1360         error = vinvalbuf(vp, flags, slpflag, 0);
 1361         while (error) {
 1362                 if (intrflg && (error = newnfs_sigintr(nmp, td)))
 1363                         goto out;
 1364                 error = vinvalbuf(vp, flags, 0, slptimeo);
 1365         }
 1366         if (NFSHASPNFS(nmp)) {
 1367                 nfscl_layoutcommit(vp, td);
 1368                 /*
 1369                  * Invalidate the attribute cache, since writes to a DS
 1370                  * won't update the size attribute.
 1371                  */
 1372                 mtx_lock(&np->n_mtx);
 1373                 np->n_attrstamp = 0;
 1374         } else
 1375                 mtx_lock(&np->n_mtx);
 1376         if (np->n_directio_asyncwr == 0)
 1377                 np->n_flag &= ~NMODIFIED;
 1378         mtx_unlock(&np->n_mtx);
 1379 out:
 1380         ncl_excl_finish(vp, old_lock);
 1381         return error;
 1382 }
 1383 
 1384 /*
 1385  * Initiate asynchronous I/O. Return an error if no nfsiods are available.
 1386  * This is mainly to avoid queueing async I/O requests when the nfsiods
 1387  * are all hung on a dead server.
 1388  *
 1389  * Note: ncl_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
 1390  * is eventually dequeued by the async daemon, ncl_doio() *will*.
 1391  */
 1392 int
 1393 ncl_asyncio(struct nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
 1394 {
 1395         int iod;
 1396         int gotiod;
 1397         int slpflag = 0;
 1398         int slptimeo = 0;
 1399         int error, error2;
 1400 
 1401         /*
 1402          * Commits are usually short and sweet so lets save some cpu and
 1403          * leave the async daemons for more important rpc's (such as reads
 1404          * and writes).
 1405          *
 1406          * Readdirplus RPCs do vget()s to acquire the vnodes for entries
 1407          * in the directory in order to update attributes. This can deadlock
 1408          * with another thread that is waiting for async I/O to be done by
 1409          * an nfsiod thread while holding a lock on one of these vnodes.
 1410          * To avoid this deadlock, don't allow the async nfsiod threads to
 1411          * perform Readdirplus RPCs.
 1412          */
 1413         mtx_lock(&ncl_iod_mutex);
 1414         if ((bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
 1415              (nmp->nm_bufqiods > ncl_numasync / 2)) ||
 1416             (bp->b_vp->v_type == VDIR && (nmp->nm_flag & NFSMNT_RDIRPLUS))) {
 1417                 mtx_unlock(&ncl_iod_mutex);
 1418                 return(EIO);
 1419         }
 1420 again:
 1421         if (nmp->nm_flag & NFSMNT_INT)
 1422                 slpflag = PCATCH;
 1423         gotiod = FALSE;
 1424 
 1425         /*
 1426          * Find a free iod to process this request.
 1427          */
 1428         for (iod = 0; iod < ncl_numasync; iod++)
 1429                 if (ncl_iodwant[iod] == NFSIOD_AVAILABLE) {
 1430                         gotiod = TRUE;
 1431                         break;
 1432                 }
 1433 
 1434         /*
 1435          * Try to create one if none are free.
 1436          */
 1437         if (!gotiod)
 1438                 ncl_nfsiodnew();
 1439         else {
 1440                 /*
 1441                  * Found one, so wake it up and tell it which
 1442                  * mount to process.
 1443                  */
 1444                 NFS_DPF(ASYNCIO, ("ncl_asyncio: waking iod %d for mount %p\n",
 1445                     iod, nmp));
 1446                 ncl_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
 1447                 ncl_iodmount[iod] = nmp;
 1448                 nmp->nm_bufqiods++;
 1449                 wakeup(&ncl_iodwant[iod]);
 1450         }
 1451 
 1452         /*
 1453          * If none are free, we may already have an iod working on this mount
 1454          * point.  If so, it will process our request.
 1455          */
 1456         if (!gotiod) {
 1457                 if (nmp->nm_bufqiods > 0) {
 1458                         NFS_DPF(ASYNCIO,
 1459                                 ("ncl_asyncio: %d iods are already processing mount %p\n",
 1460                                  nmp->nm_bufqiods, nmp));
 1461                         gotiod = TRUE;
 1462                 }
 1463         }
 1464 
 1465         /*
 1466          * If we have an iod which can process the request, then queue
 1467          * the buffer.
 1468          */
 1469         if (gotiod) {
 1470                 /*
 1471                  * Ensure that the queue never grows too large.  We still want
 1472                  * to asynchronize so we block rather then return EIO.
 1473                  */
 1474                 while (nmp->nm_bufqlen >= 2*ncl_numasync) {
 1475                         NFS_DPF(ASYNCIO,
 1476                                 ("ncl_asyncio: waiting for mount %p queue to drain\n", nmp));
 1477                         nmp->nm_bufqwant = TRUE;
 1478                         error = newnfs_msleep(td, &nmp->nm_bufq,
 1479                             &ncl_iod_mutex, slpflag | PRIBIO, "nfsaio",
 1480                            slptimeo);
 1481                         if (error) {
 1482                                 error2 = newnfs_sigintr(nmp, td);
 1483                                 if (error2) {
 1484                                         mtx_unlock(&ncl_iod_mutex);
 1485                                         return (error2);
 1486                                 }
 1487                                 if (slpflag == PCATCH) {
 1488                                         slpflag = 0;
 1489                                         slptimeo = 2 * hz;
 1490                                 }
 1491                         }
 1492                         /*
 1493                          * We might have lost our iod while sleeping,
 1494                          * so check and loop if necessary.
 1495                          */
 1496                         goto again;
 1497                 }
 1498 
 1499                 /* We might have lost our nfsiod */
 1500                 if (nmp->nm_bufqiods == 0) {
 1501                         NFS_DPF(ASYNCIO,
 1502                                 ("ncl_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
 1503                         goto again;
 1504                 }
 1505 
 1506                 if (bp->b_iocmd == BIO_READ) {
 1507                         if (bp->b_rcred == NOCRED && cred != NOCRED)
 1508                                 bp->b_rcred = crhold(cred);
 1509                 } else {
 1510                         if (bp->b_wcred == NOCRED && cred != NOCRED)
 1511                                 bp->b_wcred = crhold(cred);
 1512                 }
 1513 
 1514                 if (bp->b_flags & B_REMFREE)
 1515                         bremfreef(bp);
 1516                 BUF_KERNPROC(bp);
 1517                 TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
 1518                 nmp->nm_bufqlen++;
 1519                 if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1520                         mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);
 1521                         VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
 1522                         VTONFS(bp->b_vp)->n_directio_asyncwr++;
 1523                         mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
 1524                 }
 1525                 mtx_unlock(&ncl_iod_mutex);
 1526                 return (0);
 1527         }
 1528 
 1529         mtx_unlock(&ncl_iod_mutex);
 1530 
 1531         /*
 1532          * All the iods are busy on other mounts, so return EIO to
 1533          * force the caller to process the i/o synchronously.
 1534          */
 1535         NFS_DPF(ASYNCIO, ("ncl_asyncio: no iods available, i/o is synchronous\n"));
 1536         return (EIO);
 1537 }
 1538 
 1539 void
 1540 ncl_doio_directwrite(struct buf *bp)
 1541 {
 1542         int iomode, must_commit;
 1543         struct uio *uiop = (struct uio *)bp->b_caller1;
 1544         char *iov_base = uiop->uio_iov->iov_base;
 1545 
 1546         iomode = NFSWRITE_FILESYNC;
 1547         uiop->uio_td = NULL; /* NULL since we're in nfsiod */
 1548         ncl_writerpc(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit, 0);
 1549         KASSERT((must_commit == 0), ("ncl_doio_directwrite: Did not commit write"));
 1550         free(iov_base, M_NFSDIRECTIO);
 1551         free(uiop->uio_iov, M_NFSDIRECTIO);
 1552         free(uiop, M_NFSDIRECTIO);
 1553         if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
 1554                 struct nfsnode *np = VTONFS(bp->b_vp);
 1555                 mtx_lock(&np->n_mtx);
 1556                 if (NFSHASPNFS(VFSTONFS(vnode_mount(bp->b_vp)))) {
 1557                         /*
 1558                          * Invalidate the attribute cache, since writes to a DS
 1559                          * won't update the size attribute.
 1560                          */
 1561                         np->n_attrstamp = 0;
 1562                 }
 1563                 np->n_directio_asyncwr--;
 1564                 if (np->n_directio_asyncwr == 0) {
 1565                         np->n_flag &= ~NMODIFIED;
 1566                         if ((np->n_flag & NFSYNCWAIT)) {
 1567                                 np->n_flag &= ~NFSYNCWAIT;
 1568                                 wakeup((caddr_t)&np->n_directio_asyncwr);
 1569                         }
 1570                 }
 1571                 mtx_unlock(&np->n_mtx);
 1572         }
 1573         bp->b_vp = NULL;
 1574         uma_zfree(ncl_pbuf_zone, bp);
 1575 }
 1576 
 1577 /*
 1578  * Do an I/O operation to/from a cache block. This may be called
 1579  * synchronously or from an nfsiod.
 1580  */
 1581 int
 1582 ncl_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td,
 1583     int called_from_strategy)
 1584 {
 1585         struct uio *uiop;
 1586         struct nfsnode *np;
 1587         struct nfsmount *nmp;
 1588         int error = 0, iomode, must_commit = 0;
 1589         struct uio uio;
 1590         struct iovec io;
 1591         struct proc *p = td ? td->td_proc : NULL;
 1592         uint8_t iocmd;
 1593 
 1594         np = VTONFS(vp);
 1595         nmp = VFSTONFS(vp->v_mount);
 1596         uiop = &uio;
 1597         uiop->uio_iov = &io;
 1598         uiop->uio_iovcnt = 1;
 1599         uiop->uio_segflg = UIO_SYSSPACE;
 1600         uiop->uio_td = td;
 1601 
 1602         /*
 1603          * clear BIO_ERROR and B_INVAL state prior to initiating the I/O.  We
 1604          * do this here so we do not have to do it in all the code that
 1605          * calls us.
 1606          */
 1607         bp->b_flags &= ~B_INVAL;
 1608         bp->b_ioflags &= ~BIO_ERROR;
 1609 
 1610         KASSERT(!(bp->b_flags & B_DONE), ("ncl_doio: bp %p already marked done", bp));
 1611         iocmd = bp->b_iocmd;
 1612         if (iocmd == BIO_READ) {
 1613             io.iov_len = uiop->uio_resid = bp->b_bcount;
 1614             io.iov_base = bp->b_data;
 1615             uiop->uio_rw = UIO_READ;
 1616 
 1617             switch (vp->v_type) {
 1618             case VREG:
 1619                 uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
 1620                 NFSINCRGLOBAL(nfsstatsv1.read_bios);
 1621                 error = ncl_readrpc(vp, uiop, cr);
 1622 
 1623                 if (!error) {
 1624                     if (uiop->uio_resid) {
 1625                         /*
 1626                          * If we had a short read with no error, we must have
 1627                          * hit a file hole.  We should zero-fill the remainder.
 1628                          * This can also occur if the server hits the file EOF.
 1629                          *
 1630                          * Holes used to be able to occur due to pending
 1631                          * writes, but that is not possible any longer.
 1632                          */
 1633                         int nread = bp->b_bcount - uiop->uio_resid;
 1634                         ssize_t left = uiop->uio_resid;
 1635 
 1636                         if (left > 0)
 1637                                 bzero((char *)bp->b_data + nread, left);
 1638                         uiop->uio_resid = 0;
 1639                     }
 1640                 }
 1641                 /* ASSERT_VOP_LOCKED(vp, "ncl_doio"); */
 1642                 if (p && (vp->v_vflag & VV_TEXT)) {
 1643                         mtx_lock(&np->n_mtx);
 1644                         if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.na_mtime)) {
 1645                                 mtx_unlock(&np->n_mtx);
 1646                                 PROC_LOCK(p);
 1647                                 killproc(p, "text file modification");
 1648                                 PROC_UNLOCK(p);
 1649                         } else
 1650                                 mtx_unlock(&np->n_mtx);
 1651                 }
 1652                 break;
 1653             case VLNK:
 1654                 uiop->uio_offset = (off_t)0;
 1655                 NFSINCRGLOBAL(nfsstatsv1.readlink_bios);
 1656                 error = ncl_readlinkrpc(vp, uiop, cr);
 1657                 break;
 1658             case VDIR:
 1659                 NFSINCRGLOBAL(nfsstatsv1.readdir_bios);
 1660                 uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
 1661                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
 1662                         error = ncl_readdirplusrpc(vp, uiop, cr, td);
 1663                         if (error == NFSERR_NOTSUPP)
 1664                                 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
 1665                 }
 1666                 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
 1667                         error = ncl_readdirrpc(vp, uiop, cr, td);
 1668                 /*
 1669                  * end-of-directory sets B_INVAL but does not generate an
 1670                  * error.
 1671                  */
 1672                 if (error == 0 && uiop->uio_resid == bp->b_bcount)
 1673                         bp->b_flags |= B_INVAL;
 1674                 break;
 1675             default:
 1676                 printf("ncl_doio:  type %x unexpected\n", vp->v_type);
 1677                 break;
 1678             }
 1679             if (error) {
 1680                 bp->b_ioflags |= BIO_ERROR;
 1681                 bp->b_error = error;
 1682             }
 1683         } else {
 1684             /*
 1685              * If we only need to commit, try to commit
 1686              */
 1687             if (bp->b_flags & B_NEEDCOMMIT) {
 1688                     int retv;
 1689                     off_t off;
 1690 
 1691                     off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
 1692                     retv = ncl_commit(vp, off, bp->b_dirtyend-bp->b_dirtyoff,
 1693                         bp->b_wcred, td);
 1694                     if (retv == 0) {
 1695                             bp->b_dirtyoff = bp->b_dirtyend = 0;
 1696                             bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1697                             bp->b_resid = 0;
 1698                             bufdone(bp);
 1699                             return (0);
 1700                     }
 1701                     if (retv == NFSERR_STALEWRITEVERF) {
 1702                             ncl_clearcommit(vp->v_mount);
 1703                     }
 1704             }
 1705 
 1706             /*
 1707              * Setup for actual write
 1708              */
 1709             mtx_lock(&np->n_mtx);
 1710             if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
 1711                 bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
 1712             mtx_unlock(&np->n_mtx);
 1713 
 1714             if (bp->b_dirtyend > bp->b_dirtyoff) {
 1715                 io.iov_len = uiop->uio_resid = bp->b_dirtyend
 1716                     - bp->b_dirtyoff;
 1717                 uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
 1718                     + bp->b_dirtyoff;
 1719                 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
 1720                 uiop->uio_rw = UIO_WRITE;
 1721                 NFSINCRGLOBAL(nfsstatsv1.write_bios);
 1722 
 1723                 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
 1724                     iomode = NFSWRITE_UNSTABLE;
 1725                 else
 1726                     iomode = NFSWRITE_FILESYNC;
 1727 
 1728                 error = ncl_writerpc(vp, uiop, cr, &iomode, &must_commit,
 1729                     called_from_strategy);
 1730 
 1731                 /*
 1732                  * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
 1733                  * to cluster the buffers needing commit.  This will allow
 1734                  * the system to submit a single commit rpc for the whole
 1735                  * cluster.  We can do this even if the buffer is not 100%
 1736                  * dirty (relative to the NFS blocksize), so we optimize the
 1737                  * append-to-file-case.
 1738                  *
 1739                  * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
 1740                  * cleared because write clustering only works for commit
 1741                  * rpc's, not for the data portion of the write).
 1742                  */
 1743 
 1744                 if (!error && iomode == NFSWRITE_UNSTABLE) {
 1745                     bp->b_flags |= B_NEEDCOMMIT;
 1746                     if (bp->b_dirtyoff == 0
 1747                         && bp->b_dirtyend == bp->b_bcount)
 1748                         bp->b_flags |= B_CLUSTEROK;
 1749                 } else {
 1750                     bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
 1751                 }
 1752 
 1753                 /*
 1754                  * For an interrupted write, the buffer is still valid
 1755                  * and the write hasn't been pushed to the server yet,
 1756                  * so we can't set BIO_ERROR and report the interruption
 1757                  * by setting B_EINTR. For the B_ASYNC case, B_EINTR
 1758                  * is not relevant, so the rpc attempt is essentially
 1759                  * a noop.  For the case of a V3 write rpc not being
 1760                  * committed to stable storage, the block is still
 1761                  * dirty and requires either a commit rpc or another
 1762                  * write rpc with iomode == NFSV3WRITE_FILESYNC before
 1763                  * the block is reused. This is indicated by setting
 1764                  * the B_DELWRI and B_NEEDCOMMIT flags.
 1765                  *
 1766                  * EIO is returned by ncl_writerpc() to indicate a recoverable
 1767                  * write error and is handled as above, except that
 1768                  * B_EINTR isn't set. One cause of this is a stale stateid
 1769                  * error for the RPC that indicates recovery is required,
 1770                  * when called with called_from_strategy != 0.
 1771                  *
 1772                  * If the buffer is marked B_PAGING, it does not reside on
 1773                  * the vp's paging queues so we cannot call bdirty().  The
 1774                  * bp in this case is not an NFS cache block so we should
 1775                  * be safe. XXX
 1776                  *
 1777                  * The logic below breaks up errors into recoverable and
 1778                  * unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
 1779                  * and keep the buffer around for potential write retries.
 1780                  * For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
 1781                  * and save the error in the nfsnode. This is less than ideal
 1782                  * but necessary. Keeping such buffers around could potentially
 1783                  * cause buffer exhaustion eventually (they can never be written
 1784                  * out, so will get constantly be re-dirtied). It also causes
 1785                  * all sorts of vfs panics. For non-recoverable write errors,
 1786                  * also invalidate the attrcache, so we'll be forced to go over
 1787                  * the wire for this object, returning an error to user on next
 1788                  * call (most of the time).
 1789                  */
 1790                 if (error == EINTR || error == EIO || error == ETIMEDOUT
 1791                     || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
 1792                         bp->b_flags &= ~(B_INVAL|B_NOCACHE);
 1793                         if ((bp->b_flags & B_PAGING) == 0) {
 1794                             bdirty(bp);
 1795                             bp->b_flags &= ~B_DONE;
 1796                         }
 1797                         if ((error == EINTR || error == ETIMEDOUT) &&
 1798                             (bp->b_flags & B_ASYNC) == 0)
 1799                             bp->b_flags |= B_EINTR;
 1800                 } else {
 1801                     if (error) {
 1802                         bp->b_ioflags |= BIO_ERROR;
 1803                         bp->b_flags |= B_INVAL;
 1804                         bp->b_error = np->n_error = error;
 1805                         mtx_lock(&np->n_mtx);
 1806                         np->n_flag |= NWRITEERR;
 1807                         np->n_attrstamp = 0;
 1808                         KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
 1809                         mtx_unlock(&np->n_mtx);
 1810                     }
 1811                     bp->b_dirtyoff = bp->b_dirtyend = 0;
 1812                 }
 1813             } else {
 1814                 bp->b_resid = 0;
 1815                 bufdone(bp);
 1816                 return (0);
 1817             }
 1818         }
 1819         bp->b_resid = uiop->uio_resid;
 1820         if (must_commit)
 1821             ncl_clearcommit(vp->v_mount);
 1822         bufdone(bp);
 1823         return (error);
 1824 }
 1825 
 1826 /*
 1827  * Used to aid in handling ftruncate() operations on the NFS client side.
 1828  * Truncation creates a number of special problems for NFS.  We have to
 1829  * throw away VM pages and buffer cache buffers that are beyond EOF, and
 1830  * we have to properly handle VM pages or (potentially dirty) buffers
 1831  * that straddle the truncation point.
 1832  */
 1833 
 1834 int
 1835 ncl_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
 1836 {
 1837         struct nfsnode *np = VTONFS(vp);
 1838         u_quad_t tsize;
 1839         int biosize = vp->v_bufobj.bo_bsize;
 1840         int error = 0;
 1841 
 1842         mtx_lock(&np->n_mtx);
 1843         tsize = np->n_size;
 1844         np->n_size = nsize;
 1845         mtx_unlock(&np->n_mtx);
 1846 
 1847         if (nsize < tsize) {
 1848                 struct buf *bp;
 1849                 daddr_t lbn;
 1850                 int bufsize;
 1851 
 1852                 /*
 1853                  * vtruncbuf() doesn't get the buffer overlapping the
 1854                  * truncation point.  We may have a B_DELWRI and/or B_CACHE
 1855                  * buffer that now needs to be truncated.
 1856                  */
 1857                 error = vtruncbuf(vp, cred, nsize, biosize);
 1858                 lbn = nsize / biosize;
 1859                 bufsize = nsize - (lbn * biosize);
 1860                 bp = nfs_getcacheblk(vp, lbn, bufsize, td);
 1861                 if (!bp)
 1862                         return EINTR;
 1863                 if (bp->b_dirtyoff > bp->b_bcount)
 1864                         bp->b_dirtyoff = bp->b_bcount;
 1865                 if (bp->b_dirtyend > bp->b_bcount)
 1866                         bp->b_dirtyend = bp->b_bcount;
 1867                 bp->b_flags |= B_RELBUF;  /* don't leave garbage around */
 1868                 brelse(bp);
 1869         } else {
 1870                 vnode_pager_setsize(vp, nsize);
 1871         }
 1872         return(error);
 1873 }
 1874 

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