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freebsd-skq/sys/nfsclient/nfs_bio.c
Alan Cox 5a32489377 Make vm_page's PG_ZERO flag immutable between the time of the page's 
allocation and deallocation.  This flag's principal use is shortly after
allocation.  For such cases, clearing the flag is pointless.  The only
unusual use of PG_ZERO is in vfs_bio_clrbuf().  However, allocbuf() never
requests a prezeroed page.  So, vfs_bio_clrbuf() never sees a prezeroed
page.

Reviewed by:	tegge@
2004-05-06 05:03:23 +00:00

1556 lines
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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.
* 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];
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_flag & NSIZECHANGED)
|| (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;
np->n_flag &= ~NSIZECHANGED;
}
}
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 (bwrite(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 = bwrite(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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