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 1.45 2008/07/18 00:09:39 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 kprintf("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 kprintf("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 * NFS: If local changes have been made and this is a
373 * directory, the directory must be invalidated and
374 * the attribute cache must be cleared.
376 * GETATTR is called to synchronize the file size.
378 * If remote changes are detected local data is flushed
379 * and the cache is invalidated.
381 * NOTE: In the normal case the attribute cache is not
382 * cleared which means GETATTR may use cached data and
383 * not immediately detect changes made on the server.
385 if ((np->n_flag & NLMODIFIED) && vp->v_type == VDIR) {
387 error = nfs_vinvalbuf(vp, V_SAVE, 1);
392 error = VOP_GETATTR(vp, &vattr);
395 if (np->n_flag & NRMODIFIED) {
396 if (vp->v_type == VDIR)
398 error = nfs_vinvalbuf(vp, V_SAVE, 1);
401 np->n_flag &= ~NRMODIFIED;
404 if (np->n_flag & NDONTCACHE) {
405 switch (vp->v_type) {
407 return (nfs_readrpc(vp, uio));
409 return (nfs_readlinkrpc(vp, uio));
413 kprintf(" NDONTCACHE: type %x unexpected\n", vp->v_type);
417 switch (vp->v_type) {
419 nfsstats.biocache_reads++;
420 lbn = uio->uio_offset / biosize;
421 on = uio->uio_offset & (biosize - 1);
422 loffset = (off_t)lbn * biosize;
425 * Start the read ahead(s), as required.
427 if (nfs_numasync > 0 && nmp->nm_readahead > 0) {
428 for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
429 (off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
430 rabn = lbn + 1 + nra;
431 raoffset = (off_t)rabn * biosize;
432 if (findblk(vp, raoffset, FINDBLK_TEST) == NULL) {
433 rabp = nfs_getcacheblk(vp, raoffset, biosize, td);
436 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
437 rabp->b_flags |= B_ASYNC;
438 rabp->b_cmd = BUF_CMD_READ;
439 vfs_busy_pages(vp, rabp);
440 if (nfs_asyncio(vp, &rabp->b_bio2, td)) {
441 rabp->b_flags |= B_INVAL|B_ERROR;
442 vfs_unbusy_pages(rabp);
454 * Obtain the buffer cache block. Figure out the buffer size
455 * when we are at EOF. If we are modifying the size of the
456 * buffer based on an EOF condition we need to hold
457 * nfs_rslock() through obtaining the buffer to prevent
458 * a potential writer-appender from messing with n_size.
459 * Otherwise we may accidently truncate the buffer and
462 * Note that bcount is *not* DEV_BSIZE aligned.
467 if (loffset >= np->n_size) {
469 } else if (loffset + biosize > np->n_size) {
470 bcount = np->n_size - loffset;
472 if (bcount != biosize) {
473 switch(nfs_rslock(np)) {
486 bp = nfs_getcacheblk(vp, loffset, bcount, td);
488 if (bcount != biosize)
494 * If B_CACHE is not set, we must issue the read. If this
495 * fails, we return an error.
498 if ((bp->b_flags & B_CACHE) == 0) {
499 bp->b_cmd = BUF_CMD_READ;
500 vfs_busy_pages(vp, bp);
501 error = nfs_doio(vp, &bp->b_bio2, td);
509 * on is the offset into the current bp. Figure out how many
510 * bytes we can copy out of the bp. Note that bcount is
511 * NOT DEV_BSIZE aligned.
513 * Then figure out how many bytes we can copy into the uio.
518 n = min((unsigned)(bcount - on), uio->uio_resid);
521 biosize = min(NFS_MAXPATHLEN, np->n_size);
522 nfsstats.biocache_readlinks++;
523 bp = nfs_getcacheblk(vp, (off_t)0, biosize, td);
526 if ((bp->b_flags & B_CACHE) == 0) {
527 bp->b_cmd = BUF_CMD_READ;
528 vfs_busy_pages(vp, bp);
529 error = nfs_doio(vp, &bp->b_bio2, td);
531 bp->b_flags |= B_ERROR | B_INVAL;
536 n = min(uio->uio_resid, bp->b_bcount - bp->b_resid);
540 nfsstats.biocache_readdirs++;
541 if (np->n_direofoffset
542 && uio->uio_offset >= np->n_direofoffset) {
545 lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
546 on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
547 loffset = uio->uio_offset - on;
548 bp = nfs_getcacheblk(vp, loffset, NFS_DIRBLKSIZ, td);
552 if ((bp->b_flags & B_CACHE) == 0) {
553 bp->b_cmd = BUF_CMD_READ;
554 vfs_busy_pages(vp, bp);
555 error = nfs_doio(vp, &bp->b_bio2, td);
559 while (error == NFSERR_BAD_COOKIE) {
560 kprintf("got bad cookie vp %p bp %p\n", vp, bp);
562 error = nfs_vinvalbuf(vp, 0, 1);
564 * Yuck! The directory has been modified on the
565 * server. The only way to get the block is by
566 * reading from the beginning to get all the
569 * Leave the last bp intact unless there is an error.
570 * Loop back up to the while if the error is another
571 * NFSERR_BAD_COOKIE (double yuch!).
573 for (i = 0; i <= lbn && !error; i++) {
574 if (np->n_direofoffset
575 && (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
577 bp = nfs_getcacheblk(vp, (off_t)i * NFS_DIRBLKSIZ,
581 if ((bp->b_flags & B_CACHE) == 0) {
582 bp->b_cmd = BUF_CMD_READ;
583 vfs_busy_pages(vp, bp);
584 error = nfs_doio(vp, &bp->b_bio2, td);
586 * no error + B_INVAL == directory EOF,
589 if (error == 0 && (bp->b_flags & B_INVAL))
593 * An error will throw away the block and the
594 * for loop will break out. If no error and this
595 * is not the block we want, we throw away the
596 * block and go for the next one via the for loop.
598 if (error || i < lbn)
603 * The above while is repeated if we hit another cookie
604 * error. If we hit an error and it wasn't a cookie error,
612 * If not eof and read aheads are enabled, start one.
613 * (You need the current block first, so that you have the
614 * directory offset cookie of the next block.)
616 if (nfs_numasync > 0 && nmp->nm_readahead > 0 &&
617 (bp->b_flags & B_INVAL) == 0 &&
618 (np->n_direofoffset == 0 ||
619 loffset + NFS_DIRBLKSIZ < np->n_direofoffset) &&
620 (np->n_flag & NDONTCACHE) == 0 &&
621 findblk(vp, loffset + NFS_DIRBLKSIZ, FINDBLK_TEST) == NULL
623 rabp = nfs_getcacheblk(vp, loffset + NFS_DIRBLKSIZ,
626 if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
627 rabp->b_flags |= B_ASYNC;
628 rabp->b_cmd = BUF_CMD_READ;
629 vfs_busy_pages(vp, rabp);
630 if (nfs_asyncio(vp, &rabp->b_bio2, td)) {
631 rabp->b_flags |= B_INVAL|B_ERROR;
632 vfs_unbusy_pages(rabp);
641 * Unlike VREG files, whos buffer size ( bp->b_bcount ) is
642 * chopped for the EOF condition, we cannot tell how large
643 * NFS directories are going to be until we hit EOF. So
644 * an NFS directory buffer is *not* chopped to its EOF. Now,
645 * it just so happens that b_resid will effectively chop it
646 * to EOF. *BUT* this information is lost if the buffer goes
647 * away and is reconstituted into a B_CACHE state ( due to
648 * being VMIO ) later. So we keep track of the directory eof
649 * in np->n_direofoffset and chop it off as an extra step
652 n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
653 if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
654 n = np->n_direofoffset - uio->uio_offset;
657 kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
661 switch (vp->v_type) {
664 error = uiomove(bp->b_data + on, (int)n, uio);
668 error = uiomove(bp->b_data + on, (int)n, uio);
673 off_t old_off = uio->uio_offset;
675 struct nfs_dirent *dp;
678 * We are casting cpos to nfs_dirent, it must be
686 cpos = bp->b_data + on;
687 epos = bp->b_data + on + n;
688 while (cpos < epos && error == 0 && uio->uio_resid > 0) {
689 dp = (struct nfs_dirent *)cpos;
690 error = nfs_check_dirent(dp, (int)(epos - cpos));
693 if (vop_write_dirent(&error, uio, dp->nfs_ino,
694 dp->nfs_type, dp->nfs_namlen, dp->nfs_name)) {
697 cpos += dp->nfs_reclen;
701 uio->uio_offset = old_off + cpos - bp->b_data - on;
704 * Invalidate buffer if caching is disabled, forcing a
705 * re-read from the remote later.
707 if (np->n_flag & NDONTCACHE)
708 bp->b_flags |= B_INVAL;
711 kprintf(" nfs_bioread: type %x unexpected\n",vp->v_type);
714 } while (error == 0 && uio->uio_resid > 0 && n > 0);
719 * Userland can supply any 'seek' offset when reading a NFS directory.
720 * Validate the structure so we don't panic the kernel. Note that
721 * the element name is nul terminated and the nul is not included
726 nfs_check_dirent(struct nfs_dirent *dp, int maxlen)
728 int nfs_name_off = offsetof(struct nfs_dirent, nfs_name[0]);
730 if (nfs_name_off >= maxlen)
732 if (dp->nfs_reclen < nfs_name_off || dp->nfs_reclen > maxlen)
734 if (nfs_name_off + dp->nfs_namlen >= dp->nfs_reclen)
736 if (dp->nfs_reclen & 3)
742 * Vnode op for write using bio
744 * nfs_write(struct vnode *a_vp, struct uio *a_uio, int a_ioflag,
745 * struct ucred *a_cred)
748 nfs_write(struct vop_write_args *ap)
750 struct uio *uio = ap->a_uio;
751 struct thread *td = uio->uio_td;
752 struct vnode *vp = ap->a_vp;
753 struct nfsnode *np = VTONFS(vp);
754 int ioflag = ap->a_ioflag;
757 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
760 int n, on, error = 0, iomode, must_commit;
766 if (uio->uio_rw != UIO_WRITE)
767 panic("nfs_write mode");
768 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
769 panic("nfs_write proc");
771 if (vp->v_type != VREG)
773 if (np->n_flag & NWRITEERR) {
774 np->n_flag &= ~NWRITEERR;
775 return (np->n_error);
777 if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
778 (nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
779 (void)nfs_fsinfo(nmp, vp, td);
782 * Synchronously flush pending buffers if we are in synchronous
783 * mode or if we are appending.
785 if (ioflag & (IO_APPEND | IO_SYNC)) {
786 if (np->n_flag & NLMODIFIED) {
788 error = nfs_flush(vp, MNT_WAIT, td, 0);
789 /* error = nfs_vinvalbuf(vp, V_SAVE, 1); */
796 * If IO_APPEND then load uio_offset. We restart here if we cannot
797 * get the append lock.
800 if (ioflag & IO_APPEND) {
802 error = VOP_GETATTR(vp, &vattr);
805 uio->uio_offset = np->n_size;
808 if (uio->uio_offset < 0)
810 if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
812 if (uio->uio_resid == 0)
816 * We need to obtain the rslock if we intend to modify np->n_size
817 * in order to guarentee the append point with multiple contending
818 * writers, to guarentee that no other appenders modify n_size
819 * while we are trying to obtain a truncated buffer (i.e. to avoid
820 * accidently truncating data written by another appender due to
821 * the race), and to ensure that the buffer is populated prior to
822 * our extending of the file. We hold rslock through the entire
825 * Note that we do not synchronize the case where someone truncates
826 * the file while we are appending to it because attempting to lock
827 * this case may deadlock other parts of the system unexpectedly.
829 if ((ioflag & IO_APPEND) ||
830 uio->uio_offset + uio->uio_resid > np->n_size) {
831 switch(nfs_rslock(np)) {
846 * Maybe this should be above the vnode op call, but so long as
847 * file servers have no limits, i don't think it matters
849 if (td->td_proc && uio->uio_offset + uio->uio_resid >
850 td->td_proc->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
851 lwpsignal(td->td_proc, td->td_lwp, SIGXFSZ);
857 biosize = vp->v_mount->mnt_stat.f_iosize;
860 if ((np->n_flag & NDONTCACHE) && uio->uio_iovcnt == 1) {
861 iomode = NFSV3WRITE_FILESYNC;
862 error = nfs_writerpc(vp, uio, &iomode, &must_commit);
864 nfs_clearcommit(vp->v_mount);
867 nfsstats.biocache_writes++;
868 lbn = uio->uio_offset / biosize;
869 on = uio->uio_offset & (biosize-1);
870 loffset = uio->uio_offset - on;
871 n = min((unsigned)(biosize - on), uio->uio_resid);
874 * Handle direct append and file extension cases, calculate
875 * unaligned buffer size.
878 if (uio->uio_offset == np->n_size && n) {
880 * Get the buffer (in its pre-append state to maintain
881 * B_CACHE if it was previously set). Resize the
882 * nfsnode after we have locked the buffer to prevent
883 * readers from reading garbage.
886 bp = nfs_getcacheblk(vp, loffset, bcount, td);
891 np->n_size = uio->uio_offset + n;
892 np->n_flag |= NLMODIFIED;
893 vnode_pager_setsize(vp, np->n_size);
895 save = bp->b_flags & B_CACHE;
897 allocbuf(bp, bcount);
902 * Obtain the locked cache block first, and then
903 * adjust the file's size as appropriate.
906 if (loffset + bcount < np->n_size) {
907 if (loffset + biosize < np->n_size)
910 bcount = np->n_size - loffset;
912 bp = nfs_getcacheblk(vp, loffset, bcount, td);
913 if (uio->uio_offset + n > np->n_size) {
914 np->n_size = uio->uio_offset + n;
915 np->n_flag |= NLMODIFIED;
916 vnode_pager_setsize(vp, np->n_size);
926 * Issue a READ if B_CACHE is not set. In special-append
927 * mode, B_CACHE is based on the buffer prior to the write
928 * op and is typically set, avoiding the read. If a read
929 * is required in special append mode, the server will
930 * probably send us a short-read since we extended the file
931 * on our end, resulting in b_resid == 0 and, thusly,
932 * B_CACHE getting set.
934 * We can also avoid issuing the read if the write covers
935 * the entire buffer. We have to make sure the buffer state
936 * is reasonable in this case since we will not be initiating
937 * I/O. See the comments in kern/vfs_bio.c's getblk() for
940 * B_CACHE may also be set due to the buffer being cached
943 * When doing a UIO_NOCOPY write the buffer is not
944 * overwritten and we cannot just set B_CACHE unconditionally
945 * for full-block writes.
948 if (on == 0 && n == bcount && uio->uio_segflg != UIO_NOCOPY) {
949 bp->b_flags |= B_CACHE;
950 bp->b_flags &= ~(B_ERROR | B_INVAL);
953 if ((bp->b_flags & B_CACHE) == 0) {
954 bp->b_cmd = BUF_CMD_READ;
955 vfs_busy_pages(vp, bp);
956 error = nfs_doio(vp, &bp->b_bio2, td);
966 np->n_flag |= NLMODIFIED;
969 * If dirtyend exceeds file size, chop it down. This should
970 * not normally occur but there is an append race where it
971 * might occur XXX, so we log it.
973 * If the chopping creates a reverse-indexed or degenerate
974 * situation with dirtyoff/end, we 0 both of them.
977 if (bp->b_dirtyend > bcount) {
978 kprintf("NFS append race @%08llx:%d\n",
979 (long long)bp->b_bio2.bio_offset,
980 bp->b_dirtyend - bcount);
981 bp->b_dirtyend = bcount;
984 if (bp->b_dirtyoff >= bp->b_dirtyend)
985 bp->b_dirtyoff = bp->b_dirtyend = 0;
988 * If the new write will leave a contiguous dirty
989 * area, just update the b_dirtyoff and b_dirtyend,
990 * otherwise force a write rpc of the old dirty area.
992 * While it is possible to merge discontiguous writes due to
993 * our having a B_CACHE buffer ( and thus valid read data
994 * for the hole), we don't because it could lead to
995 * significant cache coherency problems with multiple clients,
996 * especially if locking is implemented later on.
998 * as an optimization we could theoretically maintain
999 * a linked list of discontinuous areas, but we would still
1000 * have to commit them separately so there isn't much
1001 * advantage to it except perhaps a bit of asynchronization.
1004 if (bp->b_dirtyend > 0 &&
1005 (on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
1006 if (bwrite(bp) == EINTR) {
1013 error = uiomove((char *)bp->b_data + on, n, uio);
1016 * Since this block is being modified, it must be written
1017 * again and not just committed. Since write clustering does
1018 * not work for the stage 1 data write, only the stage 2
1019 * commit rpc, we have to clear B_CLUSTEROK as well.
1021 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1024 bp->b_flags |= B_ERROR;
1030 * Only update dirtyoff/dirtyend if not a degenerate
1034 if (bp->b_dirtyend > 0) {
1035 bp->b_dirtyoff = min(on, bp->b_dirtyoff);
1036 bp->b_dirtyend = max((on + n), bp->b_dirtyend);
1038 bp->b_dirtyoff = on;
1039 bp->b_dirtyend = on + n;
1041 vfs_bio_set_validclean(bp, on, n);
1045 * If the lease is non-cachable or IO_SYNC do bwrite().
1047 * IO_INVAL appears to be unused. The idea appears to be
1048 * to turn off caching in this case. Very odd. XXX
1050 * If nfs_async is set bawrite() will use an unstable write
1051 * (build dirty bufs on the server), so we might as well
1052 * push it out with bawrite(). If nfs_async is not set we
1053 * use bdwrite() to cache dirty bufs on the client.
1055 if ((np->n_flag & NDONTCACHE) || (ioflag & IO_SYNC)) {
1056 if (ioflag & IO_INVAL)
1057 bp->b_flags |= B_NOCACHE;
1061 if (np->n_flag & NDONTCACHE) {
1062 error = nfs_vinvalbuf(vp, V_SAVE, 1);
1066 } else if ((n + on) == biosize && nfs_async) {
1071 } while (uio->uio_resid > 0 && n > 0);
1080 * Get an nfs cache block.
1082 * Allocate a new one if the block isn't currently in the cache
1083 * and return the block marked busy. If the calling process is
1084 * interrupted by a signal for an interruptible mount point, return
1087 * The caller must carefully deal with the possible B_INVAL state of
1088 * the buffer. nfs_doio() clears B_INVAL (and nfs_asyncio() clears it
1089 * indirectly), so synchronous reads can be issued without worrying about
1090 * the B_INVAL state. We have to be a little more careful when dealing
1091 * with writes (see comments in nfs_write()) when extending a file past
1095 nfs_getcacheblk(struct vnode *vp, off_t loffset, int size, struct thread *td)
1099 struct nfsmount *nmp;
1104 if (nmp->nm_flag & NFSMNT_INT) {
1105 bp = getblk(vp, loffset, size, GETBLK_PCATCH, 0);
1106 while (bp == NULL) {
1107 if (nfs_sigintr(nmp, NULL, td))
1109 bp = getblk(vp, loffset, size, 0, 2 * hz);
1112 bp = getblk(vp, loffset, size, 0, 0);
1116 * bio2, the 'device' layer. Since BIOs use 64 bit byte offsets
1117 * now, no translation is necessary.
1119 bp->b_bio2.bio_offset = loffset;
1124 * Flush and invalidate all dirty buffers. If another process is already
1125 * doing the flush, just wait for completion.
1128 nfs_vinvalbuf(struct vnode *vp, int flags, int intrflg)
1130 struct nfsnode *np = VTONFS(vp);
1131 struct nfsmount *nmp = VFSTONFS(vp->v_mount);
1132 int error = 0, slpflag, slptimeo;
1133 thread_t td = curthread;
1135 if (vp->v_flag & VRECLAIMED)
1138 if ((nmp->nm_flag & NFSMNT_INT) == 0)
1148 * First wait for any other process doing a flush to complete.
1150 while (np->n_flag & NFLUSHINPROG) {
1151 np->n_flag |= NFLUSHWANT;
1152 error = tsleep((caddr_t)&np->n_flag, 0, "nfsvinval", slptimeo);
1153 if (error && intrflg && nfs_sigintr(nmp, NULL, td))
1158 * Now, flush as required.
1160 np->n_flag |= NFLUSHINPROG;
1161 error = vinvalbuf(vp, flags, slpflag, 0);
1163 if (intrflg && nfs_sigintr(nmp, NULL, td)) {
1164 np->n_flag &= ~NFLUSHINPROG;
1165 if (np->n_flag & NFLUSHWANT) {
1166 np->n_flag &= ~NFLUSHWANT;
1167 wakeup((caddr_t)&np->n_flag);
1171 error = vinvalbuf(vp, flags, 0, slptimeo);
1173 np->n_flag &= ~(NLMODIFIED | NFLUSHINPROG);
1174 if (np->n_flag & NFLUSHWANT) {
1175 np->n_flag &= ~NFLUSHWANT;
1176 wakeup((caddr_t)&np->n_flag);
1182 * Initiate asynchronous I/O. Return an error if no nfsiods are available.
1183 * This is mainly to avoid queueing async I/O requests when the nfsiods
1184 * are all hung on a dead server.
1186 * Note: nfs_asyncio() does not clear (B_ERROR|B_INVAL) but when the bp
1187 * is eventually dequeued by the async daemon, nfs_doio() *will*.
1190 nfs_asyncio(struct vnode *vp, struct bio *bio, struct thread *td)
1192 struct buf *bp = bio->bio_buf;
1193 struct nfsmount *nmp;
1201 * If no async daemons then return EIO to force caller to run the rpc
1204 if (nfs_numasync == 0)
1207 KKASSERT(vp->v_tag == VT_NFS);
1208 nmp = VFSTONFS(vp->v_mount);
1211 * Commits are usually short and sweet so lets save some cpu and
1212 * leave the async daemons for more important rpc's (such as reads
1215 if (bp->b_cmd == BUF_CMD_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
1216 (nmp->nm_bioqiods > nfs_numasync / 2)) {
1221 if (nmp->nm_flag & NFSMNT_INT)
1226 * Find a free iod to process this request.
1228 for (i = 0; i < NFS_MAXASYNCDAEMON; i++)
1229 if (nfs_iodwant[i]) {
1231 * Found one, so wake it up and tell it which
1235 ("nfs_asyncio: waking iod %d for mount %p\n",
1237 nfs_iodwant[i] = NULL;
1238 nfs_iodmount[i] = nmp;
1240 wakeup((caddr_t)&nfs_iodwant[i]);
1246 * If none are free, we may already have an iod working on this mount
1247 * point. If so, it will process our request.
1250 if (nmp->nm_bioqiods > 0) {
1252 ("nfs_asyncio: %d iods are already processing mount %p\n",
1253 nmp->nm_bioqiods, nmp));
1259 * If we have an iod which can process the request, then queue
1264 * Ensure that the queue never grows too large. We still want
1265 * to asynchronize so we block rather then return EIO.
1267 while (nmp->nm_bioqlen >= 2*nfs_numasync) {
1269 ("nfs_asyncio: waiting for mount %p queue to drain\n", nmp));
1270 nmp->nm_bioqwant = TRUE;
1271 error = tsleep(&nmp->nm_bioq, slpflag,
1272 "nfsaio", slptimeo);
1274 if (nfs_sigintr(nmp, NULL, td))
1276 if (slpflag == PCATCH) {
1282 * We might have lost our iod while sleeping,
1283 * so check and loop if nescessary.
1285 if (nmp->nm_bioqiods == 0) {
1287 ("nfs_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
1294 * The passed bio's buffer is not necessary associated with
1295 * the NFS vnode it is being written to. Store the NFS vnode
1296 * in the BIO driver info.
1298 bio->bio_driver_info = vp;
1299 TAILQ_INSERT_TAIL(&nmp->nm_bioq, bio, bio_act);
1305 * All the iods are busy on other mounts, so return EIO to
1306 * force the caller to process the i/o synchronously.
1308 NFS_DPF(ASYNCIO, ("nfs_asyncio: no iods available, i/o is synchronous\n"));
1313 * Do an I/O operation to/from a cache block. This may be called
1314 * synchronously or from an nfsiod. The BIO is normalized for DEV_BSIZE.
1316 * NOTE! TD MIGHT BE NULL
1319 nfs_doio(struct vnode *vp, struct bio *bio, struct thread *td)
1321 struct buf *bp = bio->bio_buf;
1324 struct nfsmount *nmp;
1325 int error = 0, iomode, must_commit = 0;
1329 KKASSERT(vp->v_tag == VT_NFS);
1331 nmp = VFSTONFS(vp->v_mount);
1333 uiop->uio_iov = &io;
1334 uiop->uio_iovcnt = 1;
1335 uiop->uio_segflg = UIO_SYSSPACE;
1339 * clear B_ERROR and B_INVAL state prior to initiating the I/O. We
1340 * do this here so we do not have to do it in all the code that
1343 bp->b_flags &= ~(B_ERROR | B_INVAL);
1346 KASSERT(bp->b_cmd != BUF_CMD_DONE,
1347 ("nfs_doio: bp %p already marked done!", bp));
1349 if (bp->b_cmd == BUF_CMD_READ) {
1350 io.iov_len = uiop->uio_resid = bp->b_bcount;
1351 io.iov_base = bp->b_data;
1352 uiop->uio_rw = UIO_READ;
1354 switch (vp->v_type) {
1356 uiop->uio_offset = bio->bio_offset;
1357 nfsstats.read_bios++;
1358 error = nfs_readrpc(vp, uiop);
1361 if (uiop->uio_resid) {
1363 * If we had a short read with no error, we must have
1364 * hit a file hole. We should zero-fill the remainder.
1365 * This can also occur if the server hits the file EOF.
1367 * Holes used to be able to occur due to pending
1368 * writes, but that is not possible any longer.
1370 int nread = bp->b_bcount - uiop->uio_resid;
1371 int left = uiop->uio_resid;
1374 bzero((char *)bp->b_data + nread, left);
1375 uiop->uio_resid = 0;
1378 if (td && td->td_proc && (vp->v_flag & VTEXT) &&
1379 np->n_mtime != np->n_vattr.va_mtime.tv_sec) {
1380 uprintf("Process killed due to text file modification\n");
1381 ksignal(td->td_proc, SIGKILL);
1385 uiop->uio_offset = 0;
1386 nfsstats.readlink_bios++;
1387 error = nfs_readlinkrpc(vp, uiop);
1390 nfsstats.readdir_bios++;
1391 uiop->uio_offset = bio->bio_offset;
1392 if (nmp->nm_flag & NFSMNT_RDIRPLUS) {
1393 error = nfs_readdirplusrpc(vp, uiop);
1394 if (error == NFSERR_NOTSUPP)
1395 nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
1397 if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
1398 error = nfs_readdirrpc(vp, uiop);
1400 * end-of-directory sets B_INVAL but does not generate an
1403 if (error == 0 && uiop->uio_resid == bp->b_bcount)
1404 bp->b_flags |= B_INVAL;
1407 kprintf("nfs_doio: type %x unexpected\n",vp->v_type);
1411 bp->b_flags |= B_ERROR;
1412 bp->b_error = error;
1416 * If we only need to commit, try to commit
1418 KKASSERT(bp->b_cmd == BUF_CMD_WRITE);
1419 if (bp->b_flags & B_NEEDCOMMIT) {
1423 off = bio->bio_offset + bp->b_dirtyoff;
1424 retv = nfs_commit(vp, off,
1425 bp->b_dirtyend - bp->b_dirtyoff, td);
1427 bp->b_dirtyoff = bp->b_dirtyend = 0;
1428 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1433 if (retv == NFSERR_STALEWRITEVERF) {
1434 nfs_clearcommit(vp->v_mount);
1439 * Setup for actual write
1442 if (bio->bio_offset + bp->b_dirtyend > np->n_size)
1443 bp->b_dirtyend = np->n_size - bio->bio_offset;
1445 if (bp->b_dirtyend > bp->b_dirtyoff) {
1446 io.iov_len = uiop->uio_resid = bp->b_dirtyend
1448 uiop->uio_offset = bio->bio_offset + bp->b_dirtyoff;
1449 io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
1450 uiop->uio_rw = UIO_WRITE;
1451 nfsstats.write_bios++;
1453 if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
1454 iomode = NFSV3WRITE_UNSTABLE;
1456 iomode = NFSV3WRITE_FILESYNC;
1458 error = nfs_writerpc(vp, uiop, &iomode, &must_commit);
1461 * When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
1462 * to cluster the buffers needing commit. This will allow
1463 * the system to submit a single commit rpc for the whole
1464 * cluster. We can do this even if the buffer is not 100%
1465 * dirty (relative to the NFS blocksize), so we optimize the
1466 * append-to-file-case.
1468 * (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
1469 * cleared because write clustering only works for commit
1470 * rpc's, not for the data portion of the write).
1473 if (!error && iomode == NFSV3WRITE_UNSTABLE) {
1474 bp->b_flags |= B_NEEDCOMMIT;
1475 if (bp->b_dirtyoff == 0
1476 && bp->b_dirtyend == bp->b_bcount)
1477 bp->b_flags |= B_CLUSTEROK;
1479 bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
1483 * For an interrupted write, the buffer is still valid
1484 * and the write hasn't been pushed to the server yet,
1485 * so we can't set B_ERROR and report the interruption
1486 * by setting B_EINTR. For the B_ASYNC case, B_EINTR
1487 * is not relevant, so the rpc attempt is essentially
1488 * a noop. For the case of a V3 write rpc not being
1489 * committed to stable storage, the block is still
1490 * dirty and requires either a commit rpc or another
1491 * write rpc with iomode == NFSV3WRITE_FILESYNC before
1492 * the block is reused. This is indicated by setting
1493 * the B_DELWRI and B_NEEDCOMMIT flags.
1495 * If the buffer is marked B_PAGING, it does not reside on
1496 * the vp's paging queues so we cannot call bdirty(). The
1497 * bp in this case is not an NFS cache block so we should
1501 || (!error && (bp->b_flags & B_NEEDCOMMIT))) {
1503 bp->b_flags &= ~(B_INVAL|B_NOCACHE);
1504 if ((bp->b_flags & B_PAGING) == 0)
1506 if (error && (bp->b_flags & B_ASYNC) == 0)
1507 bp->b_flags |= B_EINTR;
1511 bp->b_flags |= B_ERROR;
1512 bp->b_error = np->n_error = error;
1513 np->n_flag |= NWRITEERR;
1515 bp->b_dirtyoff = bp->b_dirtyend = 0;
1523 bp->b_resid = uiop->uio_resid;
1525 nfs_clearcommit(vp->v_mount);
1531 * Used to aid in handling ftruncate() operations on the NFS client side.
1532 * Truncation creates a number of special problems for NFS. We have to
1533 * throw away VM pages and buffer cache buffers that are beyond EOF, and
1534 * we have to properly handle VM pages or (potentially dirty) buffers
1535 * that straddle the truncation point.
1539 nfs_meta_setsize(struct vnode *vp, struct thread *td, u_quad_t nsize)
1541 struct nfsnode *np = VTONFS(vp);
1542 u_quad_t tsize = np->n_size;
1543 int biosize = vp->v_mount->mnt_stat.f_iosize;
1548 if (np->n_size < tsize) {
1555 * vtruncbuf() doesn't get the buffer overlapping the
1556 * truncation point. We may have a B_DELWRI and/or B_CACHE
1557 * buffer that now needs to be truncated.
1559 error = vtruncbuf(vp, nsize, biosize);
1560 lbn = nsize / biosize;
1561 bufsize = nsize & (biosize - 1);
1562 loffset = nsize - bufsize;
1563 bp = nfs_getcacheblk(vp, loffset, bufsize, td);
1564 if (bp->b_dirtyoff > bp->b_bcount)
1565 bp->b_dirtyoff = bp->b_bcount;
1566 if (bp->b_dirtyend > bp->b_bcount)
1567 bp->b_dirtyend = bp->b_bcount;
1568 bp->b_flags |= B_RELBUF; /* don't leave garbage around */
1571 vnode_pager_setsize(vp, nsize);