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freebsd-skq/sys/nfsclient/nfs_bio.c
jhb 279b2b8278 Locking for the per-process resource limits structure. 
- struct plimit includes a mutex to protect a reference count.  The plimit
  structure is treated similarly to struct ucred in that is is always copy
  on write, so having a reference to a structure is sufficient to read from
  it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
  limits from a process to keep the limit structure from changing out from
  under you while reading from it.
- Various global limits that are ints are not protected by a lock since
  int writes are atomic on all the archs we support and thus a lock
  wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
  behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
  either an rlimit, or the current or max individual limit of the specified
  resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
  other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
  (it didn't used the stackgap when it should have) but uses lim_rlimit()
  and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
  but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits.  It
  also no longer uses the stackgap for accessing sysctl's for the
  ibcs2_sysconf() syscall but uses kernel_sysctl() instead.  As a result,
  ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.

Submitted by:	mtm (mostly, I only did a few cleanups and catchups)
Tested on:	i386
Compiled on:	alpha, amd64
2004-02-04 21:52:57 +00:00

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/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)nfs_bio.c 8.9 (Berkeley) 3/30/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vnode_pager.h>
#include <rpc/rpcclnt.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfsclient/nfsmount.h>
#include <nfsclient/nfsnode.h>
#include <nfs4client/nfs4.h>
/*
* Just call nfs_writebp() with the force argument set to 1.
*
* NOTE: B_DONE may or may not be set in a_bp on call.
*/
static int
nfs4_bwrite(struct buf *bp)
{
return (nfs4_writebp(bp, 1, curthread));
}
static int
nfs_bwrite(struct buf *bp)
{
return (nfs_writebp(bp, 1, curthread));
}
struct buf_ops buf_ops_nfs4 = {
"buf_ops_nfs4",
nfs4_bwrite
};
struct buf_ops buf_ops_nfs = {
"buf_ops_nfs",
nfs_bwrite
};
static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
struct thread *td);
/*
* Vnode op for VM getpages.
*/
int
nfs_getpages(struct vop_getpages_args *ap)
{
int i, error, nextoff, size, toff, count, npages;
struct uio uio;
struct iovec iov;
vm_offset_t kva;
struct buf *bp;
struct vnode *vp;
struct thread *td;
struct ucred *cred;
struct nfsmount *nmp;
vm_object_t object;
vm_page_t *pages;
GIANT_REQUIRED;
vp = ap->a_vp;
td = curthread; /* XXX */
cred = curthread->td_ucred; /* XXX */
nmp = VFSTONFS(vp->v_mount);
pages = ap->a_m;
count = ap->a_count;
if ((object = vp->v_object) == NULL) {
printf("nfs_getpages: called with non-merged cache vnode??\n");
return VM_PAGER_ERROR;
}
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
/* We'll never get here for v4, because we always have fsinfo */
(void)nfs_fsinfo(nmp, vp, cred, td);
}
npages = btoc(count);
/*
* If the requested page is partially valid, just return it and
* allow the pager to zero-out the blanks. Partially valid pages
* can only occur at the file EOF.
*/
{
vm_page_t m = pages[ap->a_reqpage];
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
if (m->valid != 0) {
/* handled by vm_fault now */
/* vm_page_zero_invalid(m, TRUE); */
for (i = 0; i < npages; ++i) {
if (i != ap->a_reqpage)
vm_page_free(pages[i]);
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
return(0);
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
}
/*
* We use only the kva address for the buffer, but this is extremely
* convienient and fast.
*/
bp = getpbuf(&nfs_pbuf_freecnt);
kva = (vm_offset_t) bp->b_data;
pmap_qenter(kva, pages, npages);
cnt.v_vnodein++;
cnt.v_vnodepgsin += npages;
iov.iov_base = (caddr_t) kva;
iov.iov_len = count;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = IDX_TO_OFF(pages[0]->pindex);
uio.uio_resid = count;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = UIO_READ;
uio.uio_td = td;
error = (nmp->nm_rpcops->nr_readrpc)(vp, &uio, cred);
pmap_qremove(kva, npages);
relpbuf(bp, &nfs_pbuf_freecnt);
if (error && (uio.uio_resid == count)) {
printf("nfs_getpages: error %d\n", error);
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = 0; i < npages; ++i) {
if (i != ap->a_reqpage)
vm_page_free(pages[i]);
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
return VM_PAGER_ERROR;
}
/*
* Calculate the number of bytes read and validate only that number
* of bytes. Note that due to pending writes, size may be 0. This
* does not mean that the remaining data is invalid!
*/
size = count - uio.uio_resid;
VM_OBJECT_LOCK(object);
vm_page_lock_queues();
for (i = 0, toff = 0; i < npages; i++, toff = nextoff) {
vm_page_t m;
nextoff = toff + PAGE_SIZE;
m = pages[i];
m->flags &= ~PG_ZERO;
if (nextoff <= size) {
/*
* Read operation filled an entire page
*/
m->valid = VM_PAGE_BITS_ALL;
vm_page_undirty(m);
} else if (size > toff) {
/*
* Read operation filled a partial page.
*/
m->valid = 0;
vm_page_set_validclean(m, 0, size - toff);
/* handled by vm_fault now */
/* vm_page_zero_invalid(m, TRUE); */
} else {
/*
* Read operation was short. If no error occured
* we may have hit a zero-fill section. We simply
* leave valid set to 0.
*/
;
}
if (i != ap->a_reqpage) {
/*
* Whether or not to leave the page activated is up in
* the air, but we should put the page on a page queue
* somewhere (it already is in the object). Result:
* It appears that emperical results show that
* deactivating pages is best.
*/
/*
* Just in case someone was asking for this page we
* now tell them that it is ok to use.
*/
if (!error) {
if (m->flags & PG_WANTED)
vm_page_activate(m);
else
vm_page_deactivate(m);
vm_page_wakeup(m);
} else {
vm_page_free(m);
}
}
}
vm_page_unlock_queues();
VM_OBJECT_UNLOCK(object);
return 0;
}
/*
* Vnode op for VM putpages.
*/
int
nfs_putpages(struct vop_putpages_args *ap)
{
struct uio uio;
struct iovec iov;
vm_offset_t kva;
struct buf *bp;
int iomode, must_commit, i, error, npages, count;
off_t offset;
int *rtvals;
struct vnode *vp;
struct thread *td;
struct ucred *cred;
struct nfsmount *nmp;
struct nfsnode *np;
vm_page_t *pages;
GIANT_REQUIRED;
vp = ap->a_vp;
np = VTONFS(vp);
td = curthread; /* XXX */
cred = curthread->td_ucred; /* XXX */
nmp = VFSTONFS(vp->v_mount);
pages = ap->a_m;
count = ap->a_count;
rtvals = ap->a_rtvals;
npages = btoc(count);
offset = IDX_TO_OFF(pages[0]->pindex);
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
(void)nfs_fsinfo(nmp, vp, cred, td);
}
for (i = 0; i < npages; i++)
rtvals[i] = VM_PAGER_AGAIN;
/*
* When putting pages, do not extend file past EOF.
*/
if (offset + count > np->n_size) {
count = np->n_size - offset;
if (count < 0)
count = 0;
}
/*
* We use only the kva address for the buffer, but this is extremely
* convienient and fast.
*/
bp = getpbuf(&nfs_pbuf_freecnt);
kva = (vm_offset_t) bp->b_data;
pmap_qenter(kva, pages, npages);
cnt.v_vnodeout++;
cnt.v_vnodepgsout += count;
iov.iov_base = (caddr_t) kva;
iov.iov_len = count;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = offset;
uio.uio_resid = count;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_rw = UIO_WRITE;
uio.uio_td = td;
if ((ap->a_sync & VM_PAGER_PUT_SYNC) == 0)
iomode = NFSV3WRITE_UNSTABLE;
else
iomode = NFSV3WRITE_FILESYNC;
error = (nmp->nm_rpcops->nr_writerpc)(vp, &uio, cred, &iomode, &must_commit);
pmap_qremove(kva, npages);
relpbuf(bp, &nfs_pbuf_freecnt);
if (!error) {
int nwritten = round_page(count - uio.uio_resid) / PAGE_SIZE;
for (i = 0; i < nwritten; i++) {
rtvals[i] = VM_PAGER_OK;
vm_page_undirty(pages[i]);
}
if (must_commit) {
nfs_clearcommit(vp->v_mount);
}
}
return rtvals[0];
}
/*
* Vnode op for read using bio
*/
int
nfs_bioread(struct vnode *vp, struct uio *uio, int ioflag, struct ucred *cred)
{
struct nfsnode *np = VTONFS(vp);
int biosize, i;
struct buf *bp = 0, *rabp;
struct vattr vattr;
struct thread *td;
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
daddr_t lbn, rabn;
int bcount;
int seqcount;
int nra, error = 0, n = 0, on = 0;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ)
panic("nfs_read mode");
#endif
if (uio->uio_resid == 0)
return (0);
if (uio->uio_offset < 0) /* XXX VDIR cookies can be negative */
return (EINVAL);
td = uio->uio_td;
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
(void)nfs_fsinfo(nmp, vp, cred, td);
if (vp->v_type != VDIR &&
(uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
return (EFBIG);
biosize = vp->v_mount->mnt_stat.f_iosize;
seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
/*
* For nfs, cache consistency can only be maintained approximately.
* Although RFC1094 does not specify the criteria, the following is
* believed to be compatible with the reference port.
* For nfs:
* If the file's modify time on the server has changed since the
* last read rpc or you have written to the file,
* you may have lost data cache consistency with the
* server, so flush all of the file's data out of the cache.
* Then force a getattr rpc to ensure that you have up to date
* attributes.
* NB: This implies that cache data can be read when up to
* NFS_ATTRTIMEO seconds out of date. If you find that you need current
* attributes this could be forced by setting n_attrstamp to 0 before
* the VOP_GETATTR() call.
*/
if (np->n_flag & NMODIFIED) {
if (vp->v_type != VREG) {
if (vp->v_type != VDIR)
panic("nfs: bioread, not dir");
(nmp->nm_rpcops->nr_invaldir)(vp);
error = nfs_vinvalbuf(vp, V_SAVE, cred, td, 1);
if (error)
return (error);
}
np->n_attrstamp = 0;
error = VOP_GETATTR(vp, &vattr, cred, td);
if (error)
return (error);
np->n_mtime = vattr.va_mtime.tv_sec;
} else {
error = VOP_GETATTR(vp, &vattr, cred, td);
if (error)
return (error);
if (np->n_mtime != vattr.va_mtime.tv_sec) {
if (vp->v_type == VDIR)
(nmp->nm_rpcops->nr_invaldir)(vp);
error = nfs_vinvalbuf(vp, V_SAVE, cred, td, 1);
if (error)
return (error);
np->n_mtime = vattr.va_mtime.tv_sec;
}
}
do {
switch (vp->v_type) {
case VREG:
nfsstats.biocache_reads++;
lbn = uio->uio_offset / biosize;
on = uio->uio_offset & (biosize - 1);
/*
* Start the read ahead(s), as required.
*/
if (nmp->nm_readahead > 0) {
for (nra = 0; nra < nmp->nm_readahead && nra < seqcount &&
(off_t)(lbn + 1 + nra) * biosize < np->n_size; nra++) {
rabn = lbn + 1 + nra;
if (incore(vp, rabn) == NULL) {
rabp = nfs_getcacheblk(vp, rabn, biosize, td);
if (!rabp)
return (EINTR);
if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
rabp->b_flags |= B_ASYNC;
rabp->b_iocmd = BIO_READ;
vfs_busy_pages(rabp, 0);
if (nfs_asyncio(rabp, cred, td)) {
rabp->b_flags |= B_INVAL;
rabp->b_ioflags |= BIO_ERROR;
vfs_unbusy_pages(rabp);
brelse(rabp);
break;
}
} else {
brelse(rabp);
}
}
}
}
/*
* Obtain the buffer cache block. Figure out the buffer size
* when we are at EOF. If we are modifying the size of the
* buffer based on an EOF condition we need to hold
* nfs_rslock() through obtaining the buffer to prevent
* a potential writer-appender from messing with n_size.
* Otherwise we may accidently truncate the buffer and
* lose dirty data.
*
* Note that bcount is *not* DEV_BSIZE aligned.
*/
again:
bcount = biosize;
if ((off_t)lbn * biosize >= np->n_size) {
bcount = 0;
} else if ((off_t)(lbn + 1) * biosize > np->n_size) {
bcount = np->n_size - (off_t)lbn * biosize;
}
if (bcount != biosize) {
switch(nfs_rslock(np, td)) {
case ENOLCK:
goto again;
/* not reached */
case EINTR:
case ERESTART:
return(EINTR);
/* not reached */
default:
break;
}
}
bp = nfs_getcacheblk(vp, lbn, bcount, td);
if (bcount != biosize)
nfs_rsunlock(np, td);
if (!bp)
return (EINTR);
/*
* If B_CACHE is not set, we must issue the read. If this
* fails, we return an error.
*/
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(bp, cred, td);
if (error) {
brelse(bp);
return (error);
}
}
/*
* on is the offset into the current bp. Figure out how many
* bytes we can copy out of the bp. Note that bcount is
* NOT DEV_BSIZE aligned.
*
* Then figure out how many bytes we can copy into the uio.
*/
n = 0;
if (on < bcount)
n = min((unsigned)(bcount - on), uio->uio_resid);
break;
case VLNK:
nfsstats.biocache_readlinks++;
bp = nfs_getcacheblk(vp, (daddr_t)0, NFS_MAXPATHLEN, td);
if (!bp)
return (EINTR);
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(bp, cred, td);
if (error) {
bp->b_ioflags |= BIO_ERROR;
brelse(bp);
return (error);
}
}
n = min(uio->uio_resid, NFS_MAXPATHLEN - bp->b_resid);
on = 0;
break;
case VDIR:
nfsstats.biocache_readdirs++;
if (np->n_direofoffset
&& uio->uio_offset >= np->n_direofoffset) {
return (0);
}
lbn = (uoff_t)uio->uio_offset / NFS_DIRBLKSIZ;
on = uio->uio_offset & (NFS_DIRBLKSIZ - 1);
bp = nfs_getcacheblk(vp, lbn, NFS_DIRBLKSIZ, td);
if (!bp)
return (EINTR);
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(bp, cred, td);
if (error) {
brelse(bp);
}
while (error == NFSERR_BAD_COOKIE) {
printf("got bad cookie vp %p bp %p\n", vp, bp);
(nmp->nm_rpcops->nr_invaldir)(vp);
error = nfs_vinvalbuf(vp, 0, cred, td, 1);
/*
* Yuck! The directory has been modified on the
* server. The only way to get the block is by
* reading from the beginning to get all the
* offset cookies.
*
* Leave the last bp intact unless there is an error.
* Loop back up to the while if the error is another
* NFSERR_BAD_COOKIE (double yuch!).
*/
for (i = 0; i <= lbn && !error; i++) {
if (np->n_direofoffset
&& (i * NFS_DIRBLKSIZ) >= np->n_direofoffset)
return (0);
bp = nfs_getcacheblk(vp, i, NFS_DIRBLKSIZ, td);
if (!bp)
return (EINTR);
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(bp, cred, td);
/*
* no error + B_INVAL == directory EOF,
* use the block.
*/
if (error == 0 && (bp->b_flags & B_INVAL))
break;
}
/*
* An error will throw away the block and the
* for loop will break out. If no error and this
* is not the block we want, we throw away the
* block and go for the next one via the for loop.
*/
if (error || i < lbn)
brelse(bp);
}
}
/*
* The above while is repeated if we hit another cookie
* error. If we hit an error and it wasn't a cookie error,
* we give up.
*/
if (error)
return (error);
}
/*
* If not eof and read aheads are enabled, start one.
* (You need the current block first, so that you have the
* directory offset cookie of the next block.)
*/
if (nmp->nm_readahead > 0 &&
(bp->b_flags & B_INVAL) == 0 &&
(np->n_direofoffset == 0 ||
(lbn + 1) * NFS_DIRBLKSIZ < np->n_direofoffset) &&
incore(vp, lbn + 1) == NULL) {
rabp = nfs_getcacheblk(vp, lbn + 1, NFS_DIRBLKSIZ, td);
if (rabp) {
if ((rabp->b_flags & (B_CACHE|B_DELWRI)) == 0) {
rabp->b_flags |= B_ASYNC;
rabp->b_iocmd = BIO_READ;
vfs_busy_pages(rabp, 0);
if (nfs_asyncio(rabp, cred, td)) {
rabp->b_flags |= B_INVAL;
rabp->b_ioflags |= BIO_ERROR;
vfs_unbusy_pages(rabp);
brelse(rabp);
}
} else {
brelse(rabp);
}
}
}
/*
* Unlike VREG files, whos buffer size ( bp->b_bcount ) is
* chopped for the EOF condition, we cannot tell how large
* NFS directories are going to be until we hit EOF. So
* an NFS directory buffer is *not* chopped to its EOF. Now,
* it just so happens that b_resid will effectively chop it
* to EOF. *BUT* this information is lost if the buffer goes
* away and is reconstituted into a B_CACHE state ( due to
* being VMIO ) later. So we keep track of the directory eof
* in np->n_direofoffset and chop it off as an extra step
* right here.
*/
n = lmin(uio->uio_resid, NFS_DIRBLKSIZ - bp->b_resid - on);
if (np->n_direofoffset && n > np->n_direofoffset - uio->uio_offset)
n = np->n_direofoffset - uio->uio_offset;
break;
default:
printf(" nfs_bioread: type %x unexpected\n", vp->v_type);
break;
};
if (n > 0) {
error = uiomove(bp->b_data + on, (int)n, uio);
}
switch (vp->v_type) {
case VREG:
break;
case VLNK:
n = 0;
break;
case VDIR:
break;
default:
printf(" nfs_bioread: type %x unexpected\n", vp->v_type);
}
brelse(bp);
} while (error == 0 && uio->uio_resid > 0 && n > 0);
return (error);
}
/*
* Vnode op for write using bio
*/
int
nfs_write(struct vop_write_args *ap)
{
int biosize;
struct uio *uio = ap->a_uio;
struct thread *td = uio->uio_td;
struct vnode *vp = ap->a_vp;
struct nfsnode *np = VTONFS(vp);
struct ucred *cred = ap->a_cred;
int ioflag = ap->a_ioflag;
struct buf *bp;
struct vattr vattr;
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
daddr_t lbn;
int bcount;
int n, on, error = 0;
int haverslock = 0;
struct proc *p = td?td->td_proc:NULL;
GIANT_REQUIRED;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_WRITE)
panic("nfs_write mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_td != curthread)
panic("nfs_write proc");
#endif
if (vp->v_type != VREG)
return (EIO);
if (np->n_flag & NWRITEERR) {
np->n_flag &= ~NWRITEERR;
return (np->n_error);
}
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0)
(void)nfs_fsinfo(nmp, vp, cred, td);
/*
* Synchronously flush pending buffers if we are in synchronous
* mode or if we are appending.
*/
if (ioflag & (IO_APPEND | IO_SYNC)) {
if (np->n_flag & NMODIFIED) {
np->n_attrstamp = 0;
error = nfs_vinvalbuf(vp, V_SAVE, cred, td, 1);
if (error)
return (error);
}
}
/*
* If IO_APPEND then load uio_offset. We restart here if we cannot
* get the append lock.
*/
restart:
if (ioflag & IO_APPEND) {
np->n_attrstamp = 0;
error = VOP_GETATTR(vp, &vattr, cred, td);
if (error)
return (error);
uio->uio_offset = np->n_size;
}
if (uio->uio_offset < 0)
return (EINVAL);
if ((uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
return (EFBIG);
if (uio->uio_resid == 0)
return (0);
/*
* We need to obtain the rslock if we intend to modify np->n_size
* in order to guarentee the append point with multiple contending
* writers, to guarentee that no other appenders modify n_size
* while we are trying to obtain a truncated buffer (i.e. to avoid
* accidently truncating data written by another appender due to
* the race), and to ensure that the buffer is populated prior to
* our extending of the file. We hold rslock through the entire
* operation.
*
* Note that we do not synchronize the case where someone truncates
* the file while we are appending to it because attempting to lock
* this case may deadlock other parts of the system unexpectedly.
*/
if ((ioflag & IO_APPEND) ||
uio->uio_offset + uio->uio_resid > np->n_size) {
switch(nfs_rslock(np, td)) {
case ENOLCK:
goto restart;
/* not reached */
case EINTR:
case ERESTART:
return(EINTR);
/* not reached */
default:
break;
}
haverslock = 1;
}
/*
* Maybe this should be above the vnode op call, but so long as
* file servers have no limits, i don't think it matters
*/
if (p != NULL) {
PROC_LOCK(p);
if (uio->uio_offset + uio->uio_resid >
lim_cur(p, RLIMIT_FSIZE)) {
psignal(p, SIGXFSZ);
PROC_UNLOCK(p);
if (haverslock)
nfs_rsunlock(np, td);
return (EFBIG);
}
PROC_UNLOCK(p);
}
biosize = vp->v_mount->mnt_stat.f_iosize;
do {
nfsstats.biocache_writes++;
lbn = uio->uio_offset / biosize;
on = uio->uio_offset & (biosize-1);
n = min((unsigned)(biosize - on), uio->uio_resid);
again:
/*
* Handle direct append and file extension cases, calculate
* unaligned buffer size.
*/
if (uio->uio_offset == np->n_size && n) {
/*
* Get the buffer (in its pre-append state to maintain
* B_CACHE if it was previously set). Resize the
* nfsnode after we have locked the buffer to prevent
* readers from reading garbage.
*/
bcount = on;
bp = nfs_getcacheblk(vp, lbn, bcount, td);
if (bp != NULL) {
long save;
np->n_size = uio->uio_offset + n;
np->n_flag |= NMODIFIED;
vnode_pager_setsize(vp, np->n_size);
save = bp->b_flags & B_CACHE;
bcount += n;
allocbuf(bp, bcount);
bp->b_flags |= save;
bp->b_magic = B_MAGIC_NFS;
if ((nmp->nm_flag & NFSMNT_NFSV4) != 0)
bp->b_op = &buf_ops_nfs4;
else
bp->b_op = &buf_ops_nfs;
}
} else {
/*
* Obtain the locked cache block first, and then
* adjust the file's size as appropriate.
*/
bcount = on + n;
if ((off_t)lbn * biosize + bcount < np->n_size) {
if ((off_t)(lbn + 1) * biosize < np->n_size)
bcount = biosize;
else
bcount = np->n_size - (off_t)lbn * biosize;
}
bp = nfs_getcacheblk(vp, lbn, bcount, td);
if (uio->uio_offset + n > np->n_size) {
np->n_size = uio->uio_offset + n;
np->n_flag |= NMODIFIED;
vnode_pager_setsize(vp, np->n_size);
}
}
if (!bp) {
error = EINTR;
break;
}
/*
* Issue a READ if B_CACHE is not set. In special-append
* mode, B_CACHE is based on the buffer prior to the write
* op and is typically set, avoiding the read. If a read
* is required in special append mode, the server will
* probably send us a short-read since we extended the file
* on our end, resulting in b_resid == 0 and, thusly,
* B_CACHE getting set.
*
* We can also avoid issuing the read if the write covers
* the entire buffer. We have to make sure the buffer state
* is reasonable in this case since we will not be initiating
* I/O. See the comments in kern/vfs_bio.c's getblk() for
* more information.
*
* B_CACHE may also be set due to the buffer being cached
* normally.
*/
if (on == 0 && n == bcount) {
bp->b_flags |= B_CACHE;
bp->b_flags &= ~B_INVAL;
bp->b_ioflags &= ~BIO_ERROR;
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(bp, cred, td);
if (error) {
brelse(bp);
break;
}
}
if (!bp) {
error = EINTR;
break;
}
if (bp->b_wcred == NOCRED)
bp->b_wcred = crhold(cred);
np->n_flag |= NMODIFIED;
/*
* If dirtyend exceeds file size, chop it down. This should
* not normally occur but there is an append race where it
* might occur XXX, so we log it.
*
* If the chopping creates a reverse-indexed or degenerate
* situation with dirtyoff/end, we 0 both of them.
*/
if (bp->b_dirtyend > bcount) {
printf("NFS append race @%lx:%d\n",
(long)bp->b_blkno * DEV_BSIZE,
bp->b_dirtyend - bcount);
bp->b_dirtyend = bcount;
}
if (bp->b_dirtyoff >= bp->b_dirtyend)
bp->b_dirtyoff = bp->b_dirtyend = 0;
/*
* If the new write will leave a contiguous dirty
* area, just update the b_dirtyoff and b_dirtyend,
* otherwise force a write rpc of the old dirty area.
*
* While it is possible to merge discontiguous writes due to
* our having a B_CACHE buffer ( and thus valid read data
* for the hole), we don't because it could lead to
* significant cache coherency problems with multiple clients,
* especially if locking is implemented later on.
*
* as an optimization we could theoretically maintain
* a linked list of discontinuous areas, but we would still
* have to commit them separately so there isn't much
* advantage to it except perhaps a bit of asynchronization.
*/
if (bp->b_dirtyend > 0 &&
(on > bp->b_dirtyend || (on + n) < bp->b_dirtyoff)) {
if (BUF_WRITE(bp) == EINTR) {
error = EINTR;
break;
}
goto again;
}
error = uiomove((char *)bp->b_data + on, n, uio);
/*
* Since this block is being modified, it must be written
* again and not just committed. Since write clustering does
* not work for the stage 1 data write, only the stage 2
* commit rpc, we have to clear B_CLUSTEROK as well.
*/
bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
if (error) {
bp->b_ioflags |= BIO_ERROR;
brelse(bp);
break;
}
/*
* Only update dirtyoff/dirtyend if not a degenerate
* condition.
*/
if (n) {
if (bp->b_dirtyend > 0) {
bp->b_dirtyoff = min(on, bp->b_dirtyoff);
bp->b_dirtyend = max((on + n), bp->b_dirtyend);
} else {
bp->b_dirtyoff = on;
bp->b_dirtyend = on + n;
}
vfs_bio_set_validclean(bp, on, n);
}
/*
* If IO_SYNC do bwrite().
*
* IO_INVAL appears to be unused. The idea appears to be
* to turn off caching in this case. Very odd. XXX
*/
if ((ioflag & IO_SYNC)) {
if (ioflag & IO_INVAL)
bp->b_flags |= B_NOCACHE;
error = BUF_WRITE(bp);
if (error)
break;
} else if ((n + on) == biosize) {
bp->b_flags |= B_ASYNC;
(void) (nmp->nm_rpcops->nr_writebp)(bp, 0, 0);
} else {
bdwrite(bp);
}
} while (uio->uio_resid > 0 && n > 0);
if (haverslock)
nfs_rsunlock(np, td);
return (error);
}
/*
* Get an nfs cache block.
*
* Allocate a new one if the block isn't currently in the cache
* and return the block marked busy. If the calling process is
* interrupted by a signal for an interruptible mount point, return
* NULL.
*
* The caller must carefully deal with the possible B_INVAL state of
* the buffer. nfs_doio() clears B_INVAL (and nfs_asyncio() clears it
* indirectly), so synchronous reads can be issued without worrying about
* the B_INVAL state. We have to be a little more careful when dealing
* with writes (see comments in nfs_write()) when extending a file past
* its EOF.
*/
static struct buf *
nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size, struct thread *td)
{
struct buf *bp;
struct mount *mp;
struct nfsmount *nmp;
mp = vp->v_mount;
nmp = VFSTONFS(mp);
if (nmp->nm_flag & NFSMNT_INT) {
bp = getblk(vp, bn, size, PCATCH, 0, 0);
while (bp == NULL) {
if (nfs_sigintr(nmp, NULL, td))
return (NULL);
bp = getblk(vp, bn, size, 0, 2 * hz, 0);
}
} else {
bp = getblk(vp, bn, size, 0, 0, 0);
}
if (vp->v_type == VREG) {
int biosize;
biosize = mp->mnt_stat.f_iosize;
bp->b_blkno = bn * (biosize / DEV_BSIZE);
}
return (bp);
}
/*
* Flush and invalidate all dirty buffers. If another process is already
* doing the flush, just wait for completion.
*/
int
nfs_vinvalbuf(struct vnode *vp, int flags, struct ucred *cred,
struct thread *td, int intrflg)
{
struct nfsnode *np = VTONFS(vp);
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
int error = 0, slpflag, slptimeo;
ASSERT_VOP_LOCKED(vp, "nfs_vinvalbuf");
/*
* XXX This check stops us from needlessly doing a vinvalbuf when
* being called through vclean(). It is not clear that this is
* unsafe.
*/
if (vp->v_iflag & VI_XLOCK)
return (0);
if ((nmp->nm_flag & NFSMNT_INT) == 0)
intrflg = 0;
if (intrflg) {
slpflag = PCATCH;
slptimeo = 2 * hz;
} else {
slpflag = 0;
slptimeo = 0;
}
/*
* First wait for any other process doing a flush to complete.
*/
while (np->n_flag & NFLUSHINPROG) {
np->n_flag |= NFLUSHWANT;
error = tsleep(&np->n_flag, PRIBIO + 2, "nfsvinval",
slptimeo);
if (error && intrflg &&
nfs_sigintr(nmp, NULL, td))
return (EINTR);
}
/*
* Now, flush as required.
*/
np->n_flag |= NFLUSHINPROG;
error = vinvalbuf(vp, flags, cred, td, slpflag, 0);
while (error) {
if (intrflg &&
nfs_sigintr(nmp, NULL, td)) {
np->n_flag &= ~NFLUSHINPROG;
if (np->n_flag & NFLUSHWANT) {
np->n_flag &= ~NFLUSHWANT;
wakeup(&np->n_flag);
}
return (EINTR);
}
error = vinvalbuf(vp, flags, cred, td, 0, slptimeo);
}
np->n_flag &= ~(NMODIFIED | NFLUSHINPROG);
if (np->n_flag & NFLUSHWANT) {
np->n_flag &= ~NFLUSHWANT;
wakeup(&np->n_flag);
}
return (0);
}
/*
* Initiate asynchronous I/O. Return an error if no nfsiods are available.
* This is mainly to avoid queueing async I/O requests when the nfsiods
* are all hung on a dead server.
*
* Note: nfs_asyncio() does not clear (BIO_ERROR|B_INVAL) but when the bp
* is eventually dequeued by the async daemon, nfs_doio() *will*.
*/
int
nfs_asyncio(struct buf *bp, struct ucred *cred, struct thread *td)
{
struct nfsmount *nmp;
int iod;
int gotiod;
int slpflag = 0;
int slptimeo = 0;
int error;
nmp = VFSTONFS(bp->b_vp->v_mount);
/*
* Commits are usually short and sweet so lets save some cpu and
* leave the async daemons for more important rpc's (such as reads
* and writes).
*/
if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
(nmp->nm_bufqiods > nfs_numasync / 2)) {
return(EIO);
}
again:
if (nmp->nm_flag & NFSMNT_INT)
slpflag = PCATCH;
gotiod = FALSE;
/*
* Find a free iod to process this request.
*/
for (iod = 0; iod < nfs_numasync; iod++)
if (nfs_iodwant[iod]) {
gotiod = TRUE;
break;
}
/*
* Try to create one if none are free.
*/
if (!gotiod) {
iod = nfs_nfsiodnew();
if (iod != -1)
gotiod = TRUE;
}
if (gotiod) {
/*
* Found one, so wake it up and tell it which
* mount to process.
*/
NFS_DPF(ASYNCIO, ("nfs_asyncio: waking iod %d for mount %p\n",
iod, nmp));
nfs_iodwant[iod] = NULL;
nfs_iodmount[iod] = nmp;
nmp->nm_bufqiods++;
wakeup(&nfs_iodwant[iod]);
}
/*
* If none are free, we may already have an iod working on this mount
* point. If so, it will process our request.
*/
if (!gotiod) {
if (nmp->nm_bufqiods > 0) {
NFS_DPF(ASYNCIO,
("nfs_asyncio: %d iods are already processing mount %p\n",
nmp->nm_bufqiods, nmp));
gotiod = TRUE;
}
}
/*
* If we have an iod which can process the request, then queue
* the buffer.
*/
if (gotiod) {
/*
* Ensure that the queue never grows too large. We still want
* to asynchronize so we block rather then return EIO.
*/
while (nmp->nm_bufqlen >= 2*nfs_numasync) {
NFS_DPF(ASYNCIO,
("nfs_asyncio: waiting for mount %p queue to drain\n", nmp));
nmp->nm_bufqwant = TRUE;
error = tsleep(&nmp->nm_bufq, slpflag | PRIBIO,
"nfsaio", slptimeo);
if (error) {
if (nfs_sigintr(nmp, NULL, td))
return (EINTR);
if (slpflag == PCATCH) {
slpflag = 0;
slptimeo = 2 * hz;
}
}
/*
* We might have lost our iod while sleeping,
* so check and loop if nescessary.
*/
if (nmp->nm_bufqiods == 0) {
NFS_DPF(ASYNCIO,
("nfs_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
goto again;
}
}
if (bp->b_iocmd == BIO_READ) {
if (bp->b_rcred == NOCRED && cred != NOCRED)
bp->b_rcred = crhold(cred);
} else {
bp->b_flags |= B_WRITEINPROG;
if (bp->b_wcred == NOCRED && cred != NOCRED)
bp->b_wcred = crhold(cred);
}
BUF_KERNPROC(bp);
TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
nmp->nm_bufqlen++;
return (0);
}
/*
* All the iods are busy on other mounts, so return EIO to
* force the caller to process the i/o synchronously.
*/
NFS_DPF(ASYNCIO, ("nfs_asyncio: no iods available, i/o is synchronous\n"));
return (EIO);
}
/*
* Do an I/O operation to/from a cache block. This may be called
* synchronously or from an nfsiod.
*/
int
nfs_doio(struct buf *bp, struct ucred *cr, struct thread *td)
{
struct uio *uiop;
struct vnode *vp;
struct nfsnode *np;
struct nfsmount *nmp;
int error = 0, iomode, must_commit = 0;
struct uio uio;
struct iovec io;
struct proc *p = td ? td->td_proc : NULL;
vp = bp->b_vp;
np = VTONFS(vp);
nmp = VFSTONFS(vp->v_mount);
uiop = &uio;
uiop->uio_iov = &io;
uiop->uio_iovcnt = 1;
uiop->uio_segflg = UIO_SYSSPACE;
uiop->uio_td = td;
/*
* clear BIO_ERROR and B_INVAL state prior to initiating the I/O. We
* do this here so we do not have to do it in all the code that
* calls us.
*/
bp->b_flags &= ~B_INVAL;
bp->b_ioflags &= ~BIO_ERROR;
KASSERT(!(bp->b_flags & B_DONE), ("nfs_doio: bp %p already marked done", bp));
if (bp->b_iocmd == BIO_READ) {
io.iov_len = uiop->uio_resid = bp->b_bcount;
io.iov_base = bp->b_data;
uiop->uio_rw = UIO_READ;
switch (vp->v_type) {
case VREG:
uiop->uio_offset = ((off_t)bp->b_blkno) * DEV_BSIZE;
nfsstats.read_bios++;
error = (nmp->nm_rpcops->nr_readrpc)(vp, uiop, cr);
if (!error) {
if (uiop->uio_resid) {
/*
* If we had a short read with no error, we must have
* hit a file hole. We should zero-fill the remainder.
* This can also occur if the server hits the file EOF.
*
* Holes used to be able to occur due to pending
* writes, but that is not possible any longer.
*/
int nread = bp->b_bcount - uiop->uio_resid;
int left = uiop->uio_resid;
if (left > 0)
bzero((char *)bp->b_data + nread, left);
uiop->uio_resid = 0;
}
}
/* ASSERT_VOP_LOCKED(vp, "nfs_doio"); */
if (p && (vp->v_vflag & VV_TEXT) &&
(np->n_mtime != np->n_vattr.va_mtime.tv_sec)) {
uprintf("Process killed due to text file modification\n");
PROC_LOCK(p);
psignal(p, SIGKILL);
_PHOLD(p);
PROC_UNLOCK(p);
}
break;
case VLNK:
uiop->uio_offset = (off_t)0;
nfsstats.readlink_bios++;
error = (nmp->nm_rpcops->nr_readlinkrpc)(vp, uiop, cr);
break;
case VDIR:
nfsstats.readdir_bios++;
uiop->uio_offset = ((u_quad_t)bp->b_lblkno) * NFS_DIRBLKSIZ;
if ((nmp->nm_flag & NFSMNT_NFSV4) != 0)
error = nfs4_readdirrpc(vp, uiop, cr);
else {
if ((nmp->nm_flag & NFSMNT_RDIRPLUS) != 0) {
error = nfs_readdirplusrpc(vp, uiop, cr);
if (error == NFSERR_NOTSUPP)
nmp->nm_flag &= ~NFSMNT_RDIRPLUS;
}
if ((nmp->nm_flag & NFSMNT_RDIRPLUS) == 0)
error = nfs_readdirrpc(vp, uiop, cr);
}
/*
* end-of-directory sets B_INVAL but does not generate an
* error.
*/
if (error == 0 && uiop->uio_resid == bp->b_bcount)
bp->b_flags |= B_INVAL;
break;
default:
printf("nfs_doio: type %x unexpected\n", vp->v_type);
break;
};
if (error) {
bp->b_ioflags |= BIO_ERROR;
bp->b_error = error;
}
} else {
/*
* If we only need to commit, try to commit
*/
if (bp->b_flags & B_NEEDCOMMIT) {
int retv;
off_t off;
off = ((u_quad_t)bp->b_blkno) * DEV_BSIZE + bp->b_dirtyoff;
bp->b_flags |= B_WRITEINPROG;
retv = (nmp->nm_rpcops->nr_commit)(
bp->b_vp, off, bp->b_dirtyend-bp->b_dirtyoff,
bp->b_wcred, td);
bp->b_flags &= ~B_WRITEINPROG;
if (retv == 0) {
bp->b_dirtyoff = bp->b_dirtyend = 0;
bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
bp->b_resid = 0;
bufdone(bp);
return (0);
}
if (retv == NFSERR_STALEWRITEVERF) {
nfs_clearcommit(bp->b_vp->v_mount);
}
}
/*
* Setup for actual write
*/
if ((off_t)bp->b_blkno * DEV_BSIZE + bp->b_dirtyend > np->n_size)
bp->b_dirtyend = np->n_size - (off_t)bp->b_blkno * DEV_BSIZE;
if (bp->b_dirtyend > bp->b_dirtyoff) {
io.iov_len = uiop->uio_resid = bp->b_dirtyend
- bp->b_dirtyoff;
uiop->uio_offset = (off_t)bp->b_blkno * DEV_BSIZE
+ bp->b_dirtyoff;
io.iov_base = (char *)bp->b_data + bp->b_dirtyoff;
uiop->uio_rw = UIO_WRITE;
nfsstats.write_bios++;
if ((bp->b_flags & (B_ASYNC | B_NEEDCOMMIT | B_NOCACHE | B_CLUSTER)) == B_ASYNC)
iomode = NFSV3WRITE_UNSTABLE;
else
iomode = NFSV3WRITE_FILESYNC;
bp->b_flags |= B_WRITEINPROG;
error = (nmp->nm_rpcops->nr_writerpc)(vp, uiop, cr, &iomode, &must_commit);
/*
* When setting B_NEEDCOMMIT also set B_CLUSTEROK to try
* to cluster the buffers needing commit. This will allow
* the system to submit a single commit rpc for the whole
* cluster. We can do this even if the buffer is not 100%
* dirty (relative to the NFS blocksize), so we optimize the
* append-to-file-case.
*
* (when clearing B_NEEDCOMMIT, B_CLUSTEROK must also be
* cleared because write clustering only works for commit
* rpc's, not for the data portion of the write).
*/
if (!error && iomode == NFSV3WRITE_UNSTABLE) {
bp->b_flags |= B_NEEDCOMMIT;
if (bp->b_dirtyoff == 0
&& bp->b_dirtyend == bp->b_bcount)
bp->b_flags |= B_CLUSTEROK;
} else {
bp->b_flags &= ~(B_NEEDCOMMIT | B_CLUSTEROK);
}
bp->b_flags &= ~B_WRITEINPROG;
/*
* For an interrupted write, the buffer is still valid
* and the write hasn't been pushed to the server yet,
* so we can't set BIO_ERROR and report the interruption
* by setting B_EINTR. For the B_ASYNC case, B_EINTR
* is not relevant, so the rpc attempt is essentially
* a noop. For the case of a V3 write rpc not being
* committed to stable storage, the block is still
* dirty and requires either a commit rpc or another
* write rpc with iomode == NFSV3WRITE_FILESYNC before
* the block is reused. This is indicated by setting
* the B_DELWRI and B_NEEDCOMMIT flags.
*
* If the buffer is marked B_PAGING, it does not reside on
* the vp's paging queues so we cannot call bdirty(). The
* bp in this case is not an NFS cache block so we should
* be safe. XXX
*/
if (error == EINTR
|| (!error && (bp->b_flags & B_NEEDCOMMIT))) {
int s;
s = splbio();
bp->b_flags &= ~(B_INVAL|B_NOCACHE);
if ((bp->b_flags & B_PAGING) == 0) {
bdirty(bp);
bp->b_flags &= ~B_DONE;
}
if (error && (bp->b_flags & B_ASYNC) == 0)
bp->b_flags |= B_EINTR;
splx(s);
} else {
if (error) {
bp->b_ioflags |= BIO_ERROR;
bp->b_error = np->n_error = error;
np->n_flag |= NWRITEERR;
}
bp->b_dirtyoff = bp->b_dirtyend = 0;
}
} else {
bp->b_resid = 0;
bufdone(bp);
return (0);
}
}
bp->b_resid = uiop->uio_resid;
if (must_commit)
nfs_clearcommit(vp->v_mount);
bufdone(bp);
return (error);
}
/*
* Used to aid in handling ftruncate() operations on the NFS client side.
* Truncation creates a number of special problems for NFS. We have to
* throw away VM pages and buffer cache buffers that are beyond EOF, and
* we have to properly handle VM pages or (potentially dirty) buffers
* that straddle the truncation point.
*/
int
nfs_meta_setsize(struct vnode *vp, struct ucred *cred, struct thread *td, u_quad_t nsize)
{
struct nfsnode *np = VTONFS(vp);
u_quad_t tsize = np->n_size;
int biosize = vp->v_mount->mnt_stat.f_iosize;
int error = 0;
np->n_size = nsize;
if (np->n_size < tsize) {
struct buf *bp;
daddr_t lbn;
int bufsize;
/*
* vtruncbuf() doesn't get the buffer overlapping the
* truncation point. We may have a B_DELWRI and/or B_CACHE
* buffer that now needs to be truncated.
*/
error = vtruncbuf(vp, cred, td, nsize, biosize);
lbn = nsize / biosize;
bufsize = nsize & (biosize - 1);
bp = nfs_getcacheblk(vp, lbn, bufsize, td);
if (bp->b_dirtyoff > bp->b_bcount)
bp->b_dirtyoff = bp->b_bcount;
if (bp->b_dirtyend > bp->b_bcount)
bp->b_dirtyend = bp->b_bcount;
bp->b_flags |= B_RELBUF; /* don't leave garbage around */
brelse(bp);
} else {
vnode_pager_setsize(vp, nsize);
}
return(error);
}
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