2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * Rick Macklem at The University of Guelph.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * @(#)nfs_bio.c 8.9 (Berkeley) 3/30/95
37 * $FreeBSD: /repoman/r/ncvs/src/sys/nfsclient/nfs_bio.c,v 1.130 2004/04/14 23:23:55 peadar Exp $
38 * $DragonFly: src/sys/vfs/nfs/nfs_bio.c,v 1.30 2006/03/27 16:18:39 dillon Exp $
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/resourcevar.h>
45 #include <sys/signalvar.h>
48 #include <sys/vnode.h>
49 #include <sys/mount.h>
50 #include <sys/kernel.h>
52 #include <sys/msfbuf.h>
55 #include <vm/vm_extern.h>
56 #include <vm/vm_page.h>
57 #include <vm/vm_object.h>
58 #include <vm/vm_pager.h>
59 #include <vm/vnode_pager.h>
61 #include <sys/thread2.h>
69 static struct buf *nfs_getcacheblk(struct vnode *vp, off_t loffset,
70 int size, struct thread *td);
71 static int nfs_check_dirent(struct nfs_dirent *dp, int maxlen);
73 extern int nfs_numasync;
74 extern int nfs_pbuf_freecnt;
75 extern struct nfsstats nfsstats;
78 * Vnode op for VM getpages.
80 * nfs_getpages(struct vnode *a_vp, vm_page_t *a_m, int a_count,
81 * int a_reqpage, vm_ooffset_t a_offset)
84 nfs_getpages(struct vop_getpages_args *ap)
86 struct thread *td = curthread; /* XXX */
87 int i, error, nextoff, size, toff, count, npages;
98 nmp = VFSTONFS(vp->v_mount);
102 if (vp->v_object == NULL) {
103 printf("nfs_getpages: called with non-merged cache vnode??\n");
104 return VM_PAGER_ERROR;
107 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
108 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
109 (void)nfs_fsinfo(nmp, vp, td);
111 npages = btoc(count);
114 * NOTE that partially valid pages may occur in cases other
115 * then file EOF, such as when a file is partially written and
116 * ftruncate()-extended to a larger size. It is also possible
117 * for the valid bits to be set on garbage beyond the file EOF and
118 * clear in the area before EOF (e.g. m->valid == 0xfc), which can
119 * occur due to vtruncbuf() and the buffer cache's handling of
120 * pages which 'straddle' buffers or when b_bufsize is not a
121 * multiple of PAGE_SIZE.... the buffer cache cannot normally
122 * clear the extra bits. This kind of situation occurs when you
123 * make a small write() (m->valid == 0x03) and then mmap() and
124 * fault in the buffer(m->valid = 0xFF). When NFS flushes the
125 * buffer (vinvalbuf() m->valid = 0xFC) we are left with a mess.
127 * This is combined with the possibility that the pages are partially
128 * dirty or that there is a buffer backing the pages that is dirty
129 * (even if m->dirty is 0).
131 * To solve this problem several hacks have been made: (1) NFS
132 * guarentees that the IO block size is a multiple of PAGE_SIZE and
133 * (2) The buffer cache, when invalidating an NFS buffer, will
134 * disregard the buffer's fragmentory b_bufsize and invalidate
135 * the whole page rather then just the piece the buffer owns.
137 * This allows us to assume that a partially valid page found here
138 * is fully valid (vm_fault will zero'd out areas of the page not
141 m = pages[ap->a_reqpage];
143 for (i = 0; i < npages; ++i) {
144 if (i != ap->a_reqpage)
145 vnode_pager_freepage(pages[i]);
151 * Use an MSF_BUF as a medium to retrieve data from the pages.
153 msf_map_pagelist(&msf, pages, npages, 0);
155 kva = msf_buf_kva(msf);
161 uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
162 uio.uio_resid = count;
163 uio.uio_segflg = UIO_SYSSPACE;
164 uio.uio_rw = UIO_READ;
167 error = nfs_readrpc(vp, &uio);
170 if (error && (uio.uio_resid == count)) {
171 printf("nfs_getpages: error %d\n", error);
172 for (i = 0; i < npages; ++i) {
173 if (i != ap->a_reqpage)
174 vnode_pager_freepage(pages[i]);
176 return VM_PAGER_ERROR;
180 * Calculate the number of bytes read and validate only that number
181 * of bytes. Note that due to pending writes, size may be 0. This
182 * does not mean that the remaining data is invalid!
185 size = count - uio.uio_resid;
187 for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
188 nextoff = toff + PAGE_SIZE;
191 m->flags &= ~PG_ZERO;
193 if (nextoff <= size) {
195 * Read operation filled an entire page
197 m->valid = VM_PAGE_BITS_ALL;
199 } else if (size > toff) {
201 * Read operation filled a partial page.
204 vm_page_set_validclean(m, 0, size - toff);
205 /* handled by vm_fault now */
206 /* vm_page_zero_invalid(m, TRUE); */
209 * Read operation was short. If no error occured
210 * we may have hit a zero-fill section. We simply
211 * leave valid set to 0.
215 if (i != ap->a_reqpage) {
217 * Whether or not to leave the page activated is up in
218 * the air, but we should put the page on a page queue
219 * somewhere (it already is in the object). Result:
220 * It appears that emperical results show that
221 * deactivating pages is best.
225 * Just in case someone was asking for this page we
226 * now tell them that it is ok to use.
229 if (m->flags & PG_WANTED)
232 vm_page_deactivate(m);
235 vnode_pager_freepage(m);
243 * Vnode op for VM putpages.
245 * nfs_putpages(struct vnode *a_vp, vm_page_t *a_m, int a_count, int a_sync,
246 * int *a_rtvals, vm_ooffset_t a_offset)
249 nfs_putpages(struct vop_putpages_args *ap)
251 struct thread *td = curthread;
255 int iomode, must_commit, i, error, npages, count;
259 struct nfsmount *nmp;
266 nmp = VFSTONFS(vp->v_mount);
269 rtvals = ap->a_rtvals;
270 npages = btoc(count);
271 offset = IDX_TO_OFF(pages[0]->pindex);
273 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
274 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
275 (void)nfs_fsinfo(nmp, vp, td);
277 for (i = 0; i < npages; i++) {
278 rtvals[i] = VM_PAGER_AGAIN;
282 * When putting pages, do not extend file past EOF.
285 if (offset + count > np->n_size) {
286 count = np->n_size - offset;
292 * Use an MSF_BUF as a medium to retrieve data from the pages.
294 msf_map_pagelist(&msf, pages, npages, 0);
296 kva = msf_buf_kva(msf);
302 uio.uio_offset = offset;
303 uio.uio_resid = count;
304 uio.uio_segflg = UIO_SYSSPACE;
305 uio.uio_rw = UIO_WRITE;
308 if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
309 iomode = NFSV3WRITE_UNSTABLE;
311 iomode = NFSV3WRITE_FILESYNC;
313 error = nfs_writerpc(vp, &uio, &iomode, &must_commit);
318 int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
319 for (i = 0; i < nwritten; i++) {
320 rtvals[i] = VM_PAGER_OK;
321 vm_page_undirty(pages[i]);
324 nfs_clearcommit(vp->v_mount);
330 * Vnode op for read using bio
333 nfs_bioread(struct vnode *vp, struct uio *uio, int ioflag)
335 struct nfsnode *np = VTONFS(vp);
337 struct buf *bp = 0, *rabp;
340 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
346 int nra, error = 0, n = 0, on = 0;
349 if (uio->uio_rw != UIO_READ)
350 panic("nfs_read mode");
352 if (uio->uio_resid == 0)
354 if (uio->uio_offset < 0) /* XXX VDIR cookies can be negative */
358 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
359 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
360 (void)nfs_fsinfo(nmp, vp, td);
361 if (vp->v_type != VDIR &&
362 (uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
364 biosize = vp->v_mount->mnt_stat.f_iosize;
365 seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
368 * For nfs, cache consistency can only be maintained approximately.
369 * Although RFC1094 does not specify the criteria, the following is
370 * believed to be compatible with the reference port.
372 * NQNFS: Full cache coherency is maintained within the loop.
374 * NFS: If local changes have been made and this is a
375 * directory, the directory must be invalidated and
376 * the attribute cache must be cleared.
378 * GETATTR is called to synchronize the file size.
380 * If remote changes are detected local data is flushed
381 * and the cache is invalidated.
384 * NOTE: In the normal case the attribute cache is not
385 * cleared which means GETATTR may use cached data and
386 * not immediately detect changes made on the server.
388 if ((np->n_flag & NLMODIFIED) && vp->v_type == VDIR) {
390 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
395 error = VOP_GETATTR(vp, &vattr, td);
398 if (np->n_flag & NRMODIFIED) {
399 if (vp->v_type == VDIR)
401 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
404 np->n_flag &= ~NRMODIFIED;
407 if (np->n_flag & NDONTCACHE) {
408 switch (vp->v_type) {
410 return (nfs_readrpc(vp, uio));
412 return (nfs_readlinkrpc(vp, uio));
416 printf(" NDONTCACHE: type %x unexpected\n", vp->v_type);
420 switch (vp->v_type) {
422 nfsstats.biocache_reads++;
423 lbn = uio->uio_offset / biosize;
424 on = uio->uio_offset & (biosize - 1);
425 loffset = (off_t)lbn * biosize;
428 * Start the read ahead(s), as required.
430 if (nfs_numasync > 0 && nmp->nm_readahead > 0) {
431 for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
432 (off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
433 rabn = lbn + 1 + nra;
434 raoffset = (off_t)rabn * biosize;
435 if (!findblk(vp, raoffset)) {
436 rabp = nfs_getcacheblk(vp, raoffset, biosize, td);
439 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
440 rabp->b_flags |= (B_READ | B_ASYNC);
441 vfs_busy_pages(rabp, 0);
442 if (nfs_asyncio(vp, &rabp->b_bio2, td)) {
443 rabp->b_flags |= B_INVAL|B_ERROR;
444 vfs_unbusy_pages(rabp);
456 * Obtain the buffer cache block. Figure out the buffer size
457 * when we are at EOF. If we are modifying the size of the
458 * buffer based on an EOF condition we need to hold
459 * nfs_rslock() through obtaining the buffer to prevent
460 * a potential writer-appender from messing with n_size.
461 * Otherwise we may accidently truncate the buffer and
464 * Note that bcount is *not* DEV_BSIZE aligned.
469 if (loffset >= np->n_size) {
471 } else if (loffset + biosize > np->n_size) {
472 bcount = np->n_size - loffset;
474 if (bcount != biosize) {
475 switch(nfs_rslock(np, td)) {
488 bp = nfs_getcacheblk(vp, loffset, bcount, td);
490 if (bcount != biosize)
491 nfs_rsunlock(np, td);
496 * If B_CACHE is not set, we must issue the read. If this
497 * fails, we return an error.
500 if ((bp->b_flags & B_CACHE) == 0) {
501 bp->b_flags |= B_READ;
502 vfs_busy_pages(bp, 0);
503 error = nfs_doio(vp, &bp->b_bio2, td);
511 * on is the offset into the current bp. Figure out how many
512 * bytes we can copy out of the bp. Note that bcount is
513 * NOT DEV_BSIZE aligned.
515 * Then figure out how many bytes we can copy into the uio.
520 n = min((unsigned)(bcount - on), uio->uio_resid);
523 nfsstats.biocache_readlinks++;
524 bp = nfs_getcacheblk(vp, (off_t)0, NFS_MAXPATHLEN, td);
527 if ((bp->b_flags & B_CACHE) == 0) {
528 bp->b_flags |= B_READ;
529 vfs_busy_pages(bp, 0);
530 error = nfs_doio(vp, &bp->b_bio2, td);
532 bp->b_flags |= B_ERROR;
537 n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
541 nfsstats.biocache_readdirs++;
542 if (np->n_direofoffset
543 && uio->uio_offset >= np->n_direofoffset) {
546 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
547 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
548 loffset = uio->uio_offset - on;
549 bp = nfs_getcacheblk(vp, loffset, NFS_DIRBLKSIZ, td);
553 if ((bp->b_flags & B_CACHE) == 0) {
554 bp->b_flags |= B_READ;
555 vfs_busy_pages(bp, 0);
556 error = nfs_doio(vp, &bp->b_bio2, td);
560 while (error == NFSERR_BAD_COOKIE) {
561 printf("got bad cookie vp %p bp %p\n", vp, bp);
563 error = nfs_vinvalbuf(vp, 0, td, 1);
565 * Yuck! The directory has been modified on the
566 * server. The only way to get the block is by
567 * reading from the beginning to get all the
570 * Leave the last bp intact unless there is an error.
571 * Loop back up to the while if the error is another
572 * NFSERR_BAD_COOKIE (double yuch!).
574 for (i = 0; i <= lbn && !error; i++) {
575 if (np->n_direofoffset
576 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
578 bp = nfs_getcacheblk(vp, (off_t)i * NFS_DIRBLKSIZ,
582 if ((bp->b_flags & B_CACHE) == 0) {
583 bp->b_flags |= B_READ;
584 vfs_busy_pages(bp, 0);
585 error = nfs_doio(vp, &bp->b_bio2, td);
587 * no error + B_INVAL == directory EOF,
590 if (error == 0 && (bp->b_flags & B_INVAL))
594 * An error will throw away the block and the
595 * for loop will break out. If no error and this
596 * is not the block we want, we throw away the
597 * block and go for the next one via the for loop.
599 if (error || i < lbn)
604 * The above while is repeated if we hit another cookie
605 * error. If we hit an error and it wasn't a cookie error,
613 * If not eof and read aheads are enabled, start one.
614 * (You need the current block first, so that you have the
615 * directory offset cookie of the next block.)
617 if (nfs_numasync > 0 && nmp->nm_readahead > 0 &&
618 (bp->b_flags & B_INVAL) == 0 &&
619 (np->n_direofoffset == 0 ||
620 loffset + NFS_DIRBLKSIZ < np->n_direofoffset) &&
621 (np->n_flag & NDONTCACHE) == 0 &&
622 !findblk(vp, loffset + NFS_DIRBLKSIZ)) {
623 rabp = nfs_getcacheblk(vp, loffset + NFS_DIRBLKSIZ,
626 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
627 rabp->b_flags |= (B_READ | B_ASYNC);
628 vfs_busy_pages(rabp, 0);
629 if (nfs_asyncio(vp, &rabp->b_bio2, td)) {
630 rabp->b_flags |= B_INVAL|B_ERROR;
631 vfs_unbusy_pages(rabp);
640 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
641 * chopped for the EOF condition, we cannot tell how large
642 * NFS directories are going to be until we hit EOF. So
643 * an NFS directory buffer is *not* chopped to its EOF. Now,
644 * it just so happens that b_resid will effectively chop it
645 * to EOF. *BUT* this information is lost if the buffer goes
646 * away and is reconstituted into a B_CACHE state ( due to
647 * being VMIO ) later. So we keep track of the directory eof
648 * in np->n_direofoffset and chop it off as an extra step
651 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
652 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
653 n = np->n_direofoffset - uio->uio_offset;
656 printf(" nfs_bioread: type %x unexpected\n",vp->v_type);
660 switch (vp->v_type) {
663 error = uiomove(bp->b_data + on, (int)n, uio);
667 error = uiomove(bp->b_data + on, (int)n, uio);
672 off_t old_off = uio->uio_offset;
674 struct nfs_dirent *dp;
677 * We are casting cpos to nfs_dirent, it must be
685 cpos = bp->b_data + on;
686 epos = bp->b_data + on + n;
687 while (cpos < epos && error == 0 && uio->uio_resid > 0) {
688 dp = (struct nfs_dirent *)cpos;
689 error = nfs_check_dirent(dp, (int)(epos - cpos));
692 if (vop_write_dirent(&error, uio, dp->nfs_ino,
693 dp->nfs_type, dp->nfs_namlen, dp->nfs_name)) {
696 cpos += dp->nfs_reclen;
700 uio->uio_offset = old_off + cpos - bp->b_data - on;
703 * Invalidate buffer if caching is disabled, forcing a
704 * re-read from the remote later.
706 if (np->n_flag & NDONTCACHE)
707 bp->b_flags |= B_INVAL;
710 printf(" nfs_bioread: type %x unexpected\n",vp->v_type);
713 } while (error == 0 && uio->uio_resid > 0 && n > 0);
718 * Userland can supply any 'seek' offset when reading a NFS directory.
719 * Validate the structure so we don't panic the kernel. Note that
720 * the element name is nul terminated and the nul is not included
725 nfs_check_dirent(struct nfs_dirent *dp, int maxlen)
727 int nfs_name_off = offsetof(struct nfs_dirent, nfs_name[0]);
729 if (nfs_name_off >= maxlen)
731 if (dp->nfs_reclen < nfs_name_off || dp->nfs_reclen > maxlen)
733 if (nfs_name_off + dp->nfs_namlen >= dp->nfs_reclen)
735 if (dp->nfs_reclen & 3)
741 * Vnode op for write using bio
743 * nfs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
744 * struct ucred *a_cred)
747 nfs_write(struct vop_write_args *ap)
749 struct uio *uio = ap->a_uio;
750 struct thread *td = uio->uio_td;
751 struct vnode *vp = ap->a_vp;
752 struct nfsnode *np = VTONFS(vp);
753 int ioflag = ap->a_ioflag;
756 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
759 int n, on, error = 0, iomode, must_commit;
765 if (uio->uio_rw != UIO_WRITE)
766 panic("nfs_write mode");
767 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
768 panic("nfs_write proc");
770 if (vp->v_type != VREG)
772 if (np->n_flag & NWRITEERR) {
773 np->n_flag &= ~NWRITEERR;
774 return (np->n_error);
776 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
777 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
778 (void)nfs_fsinfo(nmp, vp, td);
781 * Synchronously flush pending buffers if we are in synchronous
782 * mode or if we are appending.
784 if (ioflag & (IO_APPEND | IO_SYNC)) {
785 if (np->n_flag & NLMODIFIED) {
787 error = nfs_flush(vp, MNT_WAIT, td, 0);
788 /* error = nfs_vinvalbuf(vp, V_SAVE, td, 1); */
795 * If IO_APPEND then load uio_offset. We restart here if we cannot
796 * get the append lock.
799 if (ioflag & IO_APPEND) {
801 error = VOP_GETATTR(vp, &vattr, td);
804 uio->uio_offset = np->n_size;
807 if (uio->uio_offset < 0)
809 if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
811 if (uio->uio_resid == 0)
815 * We need to obtain the rslock if we intend to modify np->n_size
816 * in order to guarentee the append point with multiple contending
817 * writers, to guarentee that no other appenders modify n_size
818 * while we are trying to obtain a truncated buffer (i.e. to avoid
819 * accidently truncating data written by another appender due to
820 * the race), and to ensure that the buffer is populated prior to
821 * our extending of the file. We hold rslock through the entire
824 * Note that we do not synchronize the case where someone truncates
825 * the file while we are appending to it because attempting to lock
826 * this case may deadlock other parts of the system unexpectedly.
828 if ((ioflag & IO_APPEND) ||
829 uio->uio_offset + uio->uio_resid > np->n_size) {
830 switch(nfs_rslock(np, td)) {
845 * Maybe this should be above the vnode op call, but so long as
846 * file servers have no limits, i don't think it matters
848 if (td->td_proc && uio->uio_offset + uio->uio_resid >
849 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
850 psignal(td->td_proc, SIGXFSZ);
852 nfs_rsunlock(np, td);
856 biosize = vp->v_mount->mnt_stat.f_iosize;
859 if ((np->n_flag & NDONTCACHE) && uio->uio_iovcnt == 1) {
860 iomode = NFSV3WRITE_FILESYNC;
861 error = nfs_writerpc(vp, uio, &iomode, &must_commit);
863 nfs_clearcommit(vp->v_mount);
866 nfsstats.biocache_writes++;
867 lbn = uio->uio_offset / biosize;
868 on = uio->uio_offset & (biosize-1);
869 loffset = uio->uio_offset - on;
870 n = min((unsigned)(biosize - on), uio->uio_resid);
873 * Handle direct append and file extension cases, calculate
874 * unaligned buffer size.
877 if (uio->uio_offset == np->n_size && n) {
879 * Get the buffer (in its pre-append state to maintain
880 * B_CACHE if it was previously set). Resize the
881 * nfsnode after we have locked the buffer to prevent
882 * readers from reading garbage.
885 bp = nfs_getcacheblk(vp, loffset, bcount, td);
890 np->n_size = uio->uio_offset + n;
891 np->n_flag |= NLMODIFIED;
892 vnode_pager_setsize(vp, np->n_size);
894 save = bp->b_flags & B_CACHE;
896 allocbuf(bp, bcount);
901 * Obtain the locked cache block first, and then
902 * adjust the file's size as appropriate.
905 if (loffset + bcount < np->n_size) {
906 if (loffset + biosize < np->n_size)
909 bcount = np->n_size - loffset;
911 bp = nfs_getcacheblk(vp, loffset, bcount, td);
912 if (uio->uio_offset + n > np->n_size) {
913 np->n_size = uio->uio_offset + n;
914 np->n_flag |= NLMODIFIED;
915 vnode_pager_setsize(vp, np->n_size);
925 * Issue a READ if B_CACHE is not set. In special-append
926 * mode, B_CACHE is based on the buffer prior to the write
927 * op and is typically set, avoiding the read. If a read
928 * is required in special append mode, the server will
929 * probably send us a short-read since we extended the file
930 * on our end, resulting in b_resid == 0 and, thusly,
931 * B_CACHE getting set.
933 * We can also avoid issuing the read if the write covers
934 * the entire buffer. We have to make sure the buffer state
935 * is reasonable in this case since we will not be initiating
936 * I/O. See the comments in kern/vfs_bio.c's getblk() for
939 * B_CACHE may also be set due to the buffer being cached
943 if (on == 0 && n == bcount) {
944 bp->b_flags |= B_CACHE;
945 bp->b_flags &= ~(B_ERROR | B_INVAL);
948 if ((bp->b_flags & B_CACHE) == 0) {
949 bp->b_flags |= B_READ;
950 vfs_busy_pages(bp, 0);
951 error = nfs_doio(vp, &bp->b_bio2, td);
961 np->n_flag |= NLMODIFIED;
964 * If dirtyend exceeds file size, chop it down. This should
965 * not normally occur but there is an append race where it
966 * might occur XXX, so we log it.
968 * If the chopping creates a reverse-indexed or degenerate
969 * situation with dirtyoff/end, we 0 both of them.
972 if (bp->b_dirtyend > bcount) {
973 printf("NFS append race @%08llx:%d\n",
974 bp->b_bio2.bio_offset,
975 bp->b_dirtyend - bcount);
976 bp->b_dirtyend = bcount;
979 if (bp->b_dirtyoff >= bp->b_dirtyend)
980 bp->b_dirtyoff = bp->b_dirtyend = 0;
983 * If the new write will leave a contiguous dirty
984 * area, just update the b_dirtyoff and b_dirtyend,
985 * otherwise force a write rpc of the old dirty area.
987 * While it is possible to merge discontiguous writes due to
988 * our having a B_CACHE buffer ( and thus valid read data
989 * for the hole), we don't because it could lead to
990 * significant cache coherency problems with multiple clients,
991 * especially if locking is implemented later on.
993 * as an optimization we could theoretically maintain
994 * a linked list of discontinuous areas, but we would still
995 * have to commit them separately so there isn't much
996 * advantage to it except perhaps a bit of asynchronization.
999 if (bp->b_dirtyend > 0 &&
1000 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1001 if (VOP_BWRITE(vp, bp) == EINTR) {
1008 error = uiomove((char *)bp->b_data + on, n, uio);
1011 * Since this block is being modified, it must be written
1012 * again and not just committed. Since write clustering does
1013 * not work for the stage 1 data write, only the stage 2
1014 * commit rpc, we have to clear B_CLUSTEROK as well.
1016 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1019 bp->b_flags |= B_ERROR;
1025 * Only update dirtyoff/dirtyend if not a degenerate
1029 if (bp->b_dirtyend > 0) {
1030 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1031 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1033 bp->b_dirtyoff = on;
1034 bp->b_dirtyend = on + n;
1036 vfs_bio_set_validclean(bp, on, n);
1039 * If IO_NOWDRAIN then set B_NOWDRAIN (e.g. nfs-backed VN
1040 * filesystem). XXX also use for loopback NFS mounts.
1042 if (ioflag & IO_NOWDRAIN)
1043 bp->b_flags |= B_NOWDRAIN;
1046 * If the lease is non-cachable or IO_SYNC do bwrite().
1048 * IO_INVAL appears to be unused. The idea appears to be
1049 * to turn off caching in this case. Very odd. XXX
1051 if ((np->n_flag & NDONTCACHE) || (ioflag & IO_SYNC)) {
1052 if (ioflag & IO_INVAL)
1053 bp->b_flags |= B_NOCACHE;
1054 error = VOP_BWRITE(vp, bp);
1057 if (np->n_flag & NDONTCACHE) {
1058 error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
1062 } else if ((n + on) == biosize) {
1063 bp->b_flags |= B_ASYNC;
1064 nfs_writebp(bp, 0, 0);
1068 } while (uio->uio_resid > 0 && n > 0);
1071 nfs_rsunlock(np, td);
1077 * Get an nfs cache block.
1079 * Allocate a new one if the block isn't currently in the cache
1080 * and return the block marked busy. If the calling process is
1081 * interrupted by a signal for an interruptible mount point, return
1084 * The caller must carefully deal with the possible B_INVAL state of
1085 * the buffer. nfs_doio() clears B_INVAL (and nfs_asyncio() clears it
1086 * indirectly), so synchronous reads can be issued without worrying about
1087 * the B_INVAL state. We have to be a little more careful when dealing
1088 * with writes (see comments in nfs_write()) when extending a file past
1092 nfs_getcacheblk(struct vnode *vp, off_t loffset, int size, struct thread *td)
1096 struct nfsmount *nmp;
1101 if (nmp->nm_flag & NFSMNT_INT) {
1102 bp = getblk(vp, loffset, size, PCATCH, 0);
1103 while (bp == NULL) {
1104 if (nfs_sigintr(nmp, (struct nfsreq *)0, td))
1106 bp = getblk(vp, loffset, size, 0, 2 * hz);
1109 bp = getblk(vp, loffset, size, 0, 0);
1113 * bio2, the 'device' layer. Since BIOs use 64 bit byte offsets
1114 * now, no translation is necessary.
1116 bp->b_bio2.bio_offset = loffset;
1121 * Flush and invalidate all dirty buffers. If another process is already
1122 * doing the flush, just wait for completion.
1125 nfs_vinvalbuf(struct vnode *vp, int flags,
1126 struct thread *td, int intrflg)
1128 struct nfsnode *np = VTONFS(vp);
1129 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1130 int error = 0, slpflag, slptimeo;
1132 if (vp->v_flag & VRECLAIMED)
1135 if ((nmp->nm_flag & NFSMNT_INT) == 0)
1145 * First wait for any other process doing a flush to complete.
1147 while (np->n_flag & NFLUSHINPROG) {
1148 np->n_flag |= NFLUSHWANT;
1149 error = tsleep((caddr_t)&np->n_flag, 0, "nfsvinval", slptimeo);
1150 if (error && intrflg && nfs_sigintr(nmp, (struct nfsreq *)0, td))
1155 * Now, flush as required.
1157 np->n_flag |= NFLUSHINPROG;
1158 error = vinvalbuf(vp, flags, td, slpflag, 0);
1160 if (intrflg && nfs_sigintr(nmp, (struct nfsreq *)0, td)) {
1161 np->n_flag &= ~NFLUSHINPROG;
1162 if (np->n_flag & NFLUSHWANT) {
1163 np->n_flag &= ~NFLUSHWANT;
1164 wakeup((caddr_t)&np->n_flag);
1168 error = vinvalbuf(vp, flags, td, 0, slptimeo);
1170 np->n_flag &= ~(NLMODIFIED | NFLUSHINPROG);
1171 if (np->n_flag & NFLUSHWANT) {
1172 np->n_flag &= ~NFLUSHWANT;
1173 wakeup((caddr_t)&np->n_flag);
1179 * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1180 * This is mainly to avoid queueing async I/O requests when the nfsiods
1181 * are all hung on a dead server.
1183 * Note: nfs_asyncio() does not clear (B_ERROR|B_INVAL) but when the bp
1184 * is eventually dequeued by the async daemon, nfs_doio() *will*.
1187 nfs_asyncio(struct vnode *vp, struct bio *bio, struct thread *td)
1189 struct buf *bp = bio->bio_buf;
1190 struct nfsmount *nmp;
1198 * If no async daemons then return EIO to force caller to run the rpc
1201 if (nfs_numasync == 0)
1204 KKASSERT(vp->v_tag == VT_NFS);
1205 nmp = VFSTONFS(vp->v_mount);
1208 * Commits are usually short and sweet so lets save some cpu and
1209 * leave the async daemons for more important rpc's (such as reads
1212 if ((bp->b_flags & (B_READ|B_NEEDCOMMIT)) == B_NEEDCOMMIT &&
1213 (nmp->nm_bioqiods > nfs_numasync / 2)) {
1218 if (nmp->nm_flag & NFSMNT_INT)
1223 * Find a free iod to process this request.
1225 for (i = 0; i < NFS_MAXASYNCDAEMON; i++)
1226 if (nfs_iodwant[i]) {
1228 * Found one, so wake it up and tell it which
1232 ("nfs_asyncio: waking iod %d for mount %p\n",
1234 nfs_iodwant[i] = NULL;
1235 nfs_iodmount[i] = nmp;
1237 wakeup((caddr_t)&nfs_iodwant[i]);
1243 * If none are free, we may already have an iod working on this mount
1244 * point. If so, it will process our request.
1247 if (nmp->nm_bioqiods > 0) {
1249 ("nfs_asyncio: %d iods are already processing mount %p\n",
1250 nmp->nm_bioqiods, nmp));
1256 * If we have an iod which can process the request, then queue
1261 * Ensure that the queue never grows too large. We still want
1262 * to asynchronize so we block rather then return EIO.
1264 while (nmp->nm_bioqlen >= 2*nfs_numasync) {
1266 ("nfs_asyncio: waiting for mount %p queue to drain\n", nmp));
1267 nmp->nm_bioqwant = TRUE;
1268 error = tsleep(&nmp->nm_bioq, slpflag,
1269 "nfsaio", slptimeo);
1271 if (nfs_sigintr(nmp, NULL, td))
1273 if (slpflag == PCATCH) {
1279 * We might have lost our iod while sleeping,
1280 * so check and loop if nescessary.
1282 if (nmp->nm_bioqiods == 0) {
1284 ("nfs_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1291 * The passed bio's buffer is not necessary associated with
1292 * the NFS vnode it is being written to. Store the NFS vnode
1293 * in the BIO driver info.
1295 bio->bio_driver_info = vp;
1296 TAILQ_INSERT_TAIL(&nmp->nm_bioq, bio, bio_act);
1302 * All the iods are busy on other mounts, so return EIO to
1303 * force the caller to process the i/o synchronously.
1305 NFS_DPF(ASYNCIO, ("nfs_asyncio: no iods available, i/o is synchronous\n"));
1310 * Do an I/O operation to/from a cache block. This may be called
1311 * synchronously or from an nfsiod. The BIO is normalized for DEV_BSIZE.
1313 * NOTE! TD MIGHT BE NULL
1316 nfs_doio(struct vnode *vp, struct bio *bio, struct thread *td)
1318 struct buf *bp = bio->bio_buf;
1321 struct nfsmount *nmp;
1322 int error = 0, iomode, must_commit = 0;
1326 KKASSERT(vp->v_tag == VT_NFS);
1328 nmp = VFSTONFS(vp->v_mount);
1330 uiop->uio_iov = &io;
1331 uiop->uio_iovcnt = 1;
1332 uiop->uio_segflg = UIO_SYSSPACE;
1336 * clear B_ERROR and B_INVAL state prior to initiating the I/O. We
1337 * do this here so we do not have to do it in all the code that
1340 bp->b_flags &= ~(B_ERROR | B_INVAL);
1342 KASSERT(!(bp->b_flags & B_DONE), ("nfs_doio: bp %p already marked done", bp));
1345 * Historically, paging was done with physio, but no more.
1347 if (bp->b_flags & B_PHYS) {
1349 * ...though reading /dev/drum still gets us here.
1351 io.iov_len = uiop->uio_resid = bp->b_bcount;
1352 /* mapping was done by vmapbuf() */
1353 io.iov_base = bp->b_data;
1354 uiop->uio_offset = bio->bio_offset;
1355 if (bp->b_flags & B_READ) {
1356 uiop->uio_rw = UIO_READ;
1357 nfsstats.read_physios++;
1358 error = nfs_readrpc(vp, uiop);
1362 iomode = NFSV3WRITE_DATASYNC;
1363 uiop->uio_rw = UIO_WRITE;
1364 nfsstats.write_physios++;
1365 error = nfs_writerpc(vp, uiop, &iomode, &com);
1368 bp->b_flags |= B_ERROR;
1369 bp->b_error = error;
1371 } else if (bp->b_flags & B_READ) {
1372 io.iov_len = uiop->uio_resid = bp->b_bcount;
1373 io.iov_base = bp->b_data;
1374 uiop->uio_rw = UIO_READ;
1376 switch (vp->v_type) {
1378 uiop->uio_offset = bio->bio_offset;
1379 nfsstats.read_bios++;
1380 error = nfs_readrpc(vp, uiop);
1383 if (uiop->uio_resid) {
1385 * If we had a short read with no error, we must have
1386 * hit a file hole. We should zero-fill the remainder.
1387 * This can also occur if the server hits the file EOF.
1389 * Holes used to be able to occur due to pending
1390 * writes, but that is not possible any longer.
1392 int nread = bp->b_bcount - uiop->uio_resid;
1393 int left = uiop->uio_resid;
1396 bzero((char *)bp->b_data + nread, left);
1397 uiop->uio_resid = 0;
1400 if (td && td->td_proc && (vp->v_flag & VTEXT) &&
1401 np->n_mtime != np->n_vattr.va_mtime.tv_sec) {
1402 uprintf("Process killed due to text file modification\n");
1403 psignal(td->td_proc, SIGKILL);
1407 uiop->uio_offset = 0;
1408 nfsstats.readlink_bios++;
1409 error = nfs_readlinkrpc(vp, uiop);
1412 nfsstats.readdir_bios++;
1413 uiop->uio_offset = bio->bio_offset;
1414 if (nmp->nm_flag & NFSMNT_RDIRPLUS) {
1415 error = nfs_readdirplusrpc(vp, uiop);
1416 if (error == NFSERR_NOTSUPP)
1417 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1419 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1420 error = nfs_readdirrpc(vp, uiop);
1422 * end-of-directory sets B_INVAL but does not generate an
1425 if (error == 0 && uiop->uio_resid == bp->b_bcount)
1426 bp->b_flags |= B_INVAL;
1429 printf("nfs_doio: type %x unexpected\n",vp->v_type);
1433 bp->b_flags |= B_ERROR;
1434 bp->b_error = error;
1438 * If we only need to commit, try to commit
1440 if (bp->b_flags & B_NEEDCOMMIT) {
1444 off = bio->bio_offset + bp->b_dirtyoff;
1445 retv = nfs_commit(vp, off,
1446 bp->b_dirtyend - bp->b_dirtyoff, td);
1448 bp->b_dirtyoff = bp->b_dirtyend = 0;
1449 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1454 if (retv == NFSERR_STALEWRITEVERF) {
1455 nfs_clearcommit(vp->v_mount);
1460 * Setup for actual write
1463 if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1464 bp->b_dirtyend = np->n_size - bio->bio_offset;
1466 if (bp->b_dirtyend > bp->b_dirtyoff) {
1467 io.iov_len = uiop->uio_resid = bp->b_dirtyend
1469 uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
1470 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1471 uiop->uio_rw = UIO_WRITE;
1472 nfsstats.write_bios++;
1474 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1475 iomode = NFSV3WRITE_UNSTABLE;
1477 iomode = NFSV3WRITE_FILESYNC;
1479 error = nfs_writerpc(vp, uiop, &iomode, &must_commit);
1482 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1483 * to cluster the buffers needing commit. This will allow
1484 * the system to submit a single commit rpc for the whole
1485 * cluster. We can do this even if the buffer is not 100%
1486 * dirty (relative to the NFS blocksize), so we optimize the
1487 * append-to-file-case.
1489 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1490 * cleared because write clustering only works for commit
1491 * rpc's, not for the data portion of the write).
1494 if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1495 bp->b_flags |= B_NEEDCOMMIT;
1496 if (bp->b_dirtyoff == 0
1497 && bp->b_dirtyend == bp->b_bcount)
1498 bp->b_flags |= B_CLUSTEROK;
1500 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1504 * For an interrupted write, the buffer is still valid
1505 * and the write hasn't been pushed to the server yet,
1506 * so we can't set B_ERROR and report the interruption
1507 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1508 * is not relevant, so the rpc attempt is essentially
1509 * a noop. For the case of a V3 write rpc not being
1510 * committed to stable storage, the block is still
1511 * dirty and requires either a commit rpc or another
1512 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1513 * the block is reused. This is indicated by setting
1514 * the B_DELWRI and B_NEEDCOMMIT flags.
1516 * If the buffer is marked B_PAGING, it does not reside on
1517 * the vp's paging queues so we cannot call bdirty(). The
1518 * bp in this case is not an NFS cache block so we should
1522 || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1524 bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1525 if ((bp->b_flags & B_PAGING) == 0) {
1527 bp->b_flags &= ~B_DONE;
1529 if (error && (bp->b_flags & B_ASYNC) == 0)
1530 bp->b_flags |= B_EINTR;
1534 bp->b_flags |= B_ERROR;
1535 bp->b_error = np->n_error = error;
1536 np->n_flag |= NWRITEERR;
1538 bp->b_dirtyoff = bp->b_dirtyend = 0;
1546 bp->b_resid = uiop->uio_resid;
1548 nfs_clearcommit(vp->v_mount);
1554 * Used to aid in handling ftruncate() operations on the NFS client side.
1555 * Truncation creates a number of special problems for NFS. We have to
1556 * throw away VM pages and buffer cache buffers that are beyond EOF, and
1557 * we have to properly handle VM pages or (potentially dirty) buffers
1558 * that straddle the truncation point.
1562 nfs_meta_setsize(struct vnode *vp, struct thread *td, u_quad_t nsize)
1564 struct nfsnode *np = VTONFS(vp);
1565 u_quad_t tsize = np->n_size;
1566 int biosize = vp->v_mount->mnt_stat.f_iosize;
1571 if (np->n_size < tsize) {
1578 * vtruncbuf() doesn't get the buffer overlapping the
1579 * truncation point. We may have a B_DELWRI and/or B_CACHE
1580 * buffer that now needs to be truncated.
1582 error = vtruncbuf(vp, td, nsize, biosize);
1583 lbn = nsize / biosize;
1584 bufsize = nsize & (biosize - 1);
1585 loffset = nsize - bufsize;
1586 bp = nfs_getcacheblk(vp, loffset, bufsize, td);
1587 if (bp->b_dirtyoff > bp->b_bcount)
1588 bp->b_dirtyoff = bp->b_bcount;
1589 if (bp->b_dirtyend > bp->b_bcount)
1590 bp->b_dirtyend = bp->b_bcount;
1591 bp->b_flags |= B_RELBUF; /* don't leave garbage around */
1594 vnode_pager_setsize(vp, nsize);