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freebsd-dev/sys/nfsclient/nfs_bio.c
Konstantin Belousov 223073fd1a Do not synchronously start the nfsiod threads at all. The r212506 
fixed the issues with file descriptor locks, but the same problems are
present for vnode lock/user map lock.

If the nfs_asyncio() cannot find the free nfsiod, schedule task to
create new nfsiod and return error. This causes fall back to the
synchronous i/o for nfs_strategy(), or does not start read at all in
the case of readahead. The caller that holds vnode and potentially
user map lock does not wait for kproc_create() to finish, preventing
the LORs.

The change effectively reverts r203072, because we never hand off the
request to newly created nfsiod thread anymore.

Reviewed by:	jhb
Tested by:	jhb, pluknet
MFC after:	3 weeks
2010-10-18 19:06:46 +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.
* 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 "opt_kdtrace.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/proc.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 <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfsclient/nfsmount.h>
#include <nfsclient/nfsnode.h>
#include <nfsclient/nfs_kdtrace.h>
static struct buf *nfs_getcacheblk(struct vnode *vp, daddr_t bn, int size,
struct thread *td);
static int nfs_directio_write(struct vnode *vp, struct uio *uiop,
struct ucred *cred, int ioflag);
extern int nfs_directio_enable;
extern int nfs_directio_allow_mmap;
/*
* 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;
struct nfsnode *np;
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;
if ((object = vp->v_object) == NULL) {
nfs_printf("nfs_getpages: called with non-merged cache vnode??\n");
return (VM_PAGER_ERROR);
}
if (nfs_directio_enable && !nfs_directio_allow_mmap) {
mtx_lock(&np->n_mtx);
if ((np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
mtx_unlock(&np->n_mtx);
nfs_printf("nfs_getpages: called on non-cacheable vnode??\n");
return (VM_PAGER_ERROR);
} else
mtx_unlock(&np->n_mtx);
}
mtx_lock(&nmp->nm_mtx);
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
mtx_unlock(&nmp->nm_mtx);
/* We'll never get here for v4, because we always have fsinfo */
(void)nfs_fsinfo(nmp, vp, cred, td);
} else
mtx_unlock(&nmp->nm_mtx);
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_OBJECT_LOCK(object);
if (pages[ap->a_reqpage]->valid != 0) {
for (i = 0; i < npages; ++i) {
if (i != ap->a_reqpage) {
vm_page_lock(pages[i]);
vm_page_free(pages[i]);
vm_page_unlock(pages[i]);
}
}
VM_OBJECT_UNLOCK(object);
return (0);
}
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);
PCPU_INC(cnt.v_vnodein);
PCPU_ADD(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)) {
nfs_printf("nfs_getpages: error %d\n", error);
VM_OBJECT_LOCK(object);
for (i = 0; i < npages; ++i) {
if (i != ap->a_reqpage) {
vm_page_lock(pages[i]);
vm_page_free(pages[i]);
vm_page_unlock(pages[i]);
}
}
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);
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;
KASSERT(m->dirty == 0,
("nfs_getpages: page %p is dirty", m));
} else if (size > toff) {
/*
* Read operation filled a partial page.
*/
m->valid = 0;
vm_page_set_valid(m, 0, size - toff);
KASSERT(m->dirty == 0,
("nfs_getpages: page %p is dirty", m));
} 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->oflags & VPO_WANTED) {
vm_page_lock(m);
vm_page_activate(m);
vm_page_unlock(m);
} else {
vm_page_lock(m);
vm_page_deactivate(m);
vm_page_unlock(m);
}
vm_page_wakeup(m);
} else {
vm_page_lock(m);
vm_page_free(m);
vm_page_unlock(m);
}
}
}
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;
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);
mtx_lock(&nmp->nm_mtx);
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
mtx_unlock(&nmp->nm_mtx);
(void)nfs_fsinfo(nmp, vp, cred, td);
} else
mtx_unlock(&nmp->nm_mtx);
mtx_lock(&np->n_mtx);
if (nfs_directio_enable && !nfs_directio_allow_mmap &&
(np->n_flag & NNONCACHE) && (vp->v_type == VREG)) {
mtx_unlock(&np->n_mtx);
nfs_printf("nfs_putpages: called on noncache-able vnode??\n");
mtx_lock(&np->n_mtx);
}
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;
}
mtx_unlock(&np->n_mtx);
/*
* 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);
PCPU_INC(cnt.v_vnodeout);
PCPU_ADD(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];
}
/*
* 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.
*/
static inline int
nfs_bioread_check_cons(struct vnode *vp, struct thread *td, struct ucred *cred)
{
int error = 0;
struct vattr vattr;
struct nfsnode *np = VTONFS(vp);
int old_lock;
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
/*
* Grab the exclusive lock before checking whether the cache is
* consistent.
* XXX - We can make this cheaper later (by acquiring cheaper locks).
* But for now, this suffices.
*/
old_lock = nfs_upgrade_vnlock(vp);
if (vp->v_iflag & VI_DOOMED) {
nfs_downgrade_vnlock(vp, old_lock);
return (EBADF);
}
mtx_lock(&np->n_mtx);
if (np->n_flag & NMODIFIED) {
mtx_unlock(&np->n_mtx);
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, td, 1);
if (error)
goto out;
}
np->n_attrstamp = 0;
KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
error = VOP_GETATTR(vp, &vattr, cred);
if (error)
goto out;
mtx_lock(&np->n_mtx);
np->n_mtime = vattr.va_mtime;
mtx_unlock(&np->n_mtx);
} else {
mtx_unlock(&np->n_mtx);
error = VOP_GETATTR(vp, &vattr, cred);
if (error)
return (error);
mtx_lock(&np->n_mtx);
if ((np->n_flag & NSIZECHANGED)
|| (NFS_TIMESPEC_COMPARE(&np->n_mtime, &vattr.va_mtime))) {
mtx_unlock(&np->n_mtx);
if (vp->v_type == VDIR)
(nmp->nm_rpcops->nr_invaldir)(vp);
error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
if (error)
goto out;
mtx_lock(&np->n_mtx);
np->n_mtime = vattr.va_mtime;
np->n_flag &= ~NSIZECHANGED;
}
mtx_unlock(&np->n_mtx);
}
out:
nfs_downgrade_vnlock(vp, old_lock);
return error;
}
/*
* 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, *rabp;
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;
KASSERT(uio->uio_rw == UIO_READ, ("nfs_read mode"));
if (uio->uio_resid == 0)
return (0);
if (uio->uio_offset < 0) /* XXX VDIR cookies can be negative */
return (EINVAL);
td = uio->uio_td;
mtx_lock(&nmp->nm_mtx);
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
mtx_unlock(&nmp->nm_mtx);
(void)nfs_fsinfo(nmp, vp, cred, td);
} else
mtx_unlock(&nmp->nm_mtx);
if (vp->v_type != VDIR &&
(uio->uio_offset + uio->uio_resid) > nmp->nm_maxfilesize)
return (EFBIG);
if (nfs_directio_enable && (ioflag & IO_DIRECT) && (vp->v_type == VREG))
/* No caching/ no readaheads. Just read data into the user buffer */
return nfs_readrpc(vp, uio, cred);
biosize = vp->v_mount->mnt_stat.f_iosize;
seqcount = (int)((off_t)(ioflag >> IO_SEQSHIFT) * biosize / BKVASIZE);
error = nfs_bioread_check_cons(vp, td, cred);
if (error)
return error;
do {
u_quad_t nsize;
mtx_lock(&np->n_mtx);
nsize = np->n_size;
mtx_unlock(&np->n_mtx);
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 < nsize; nra++) {
rabn = lbn + 1 + nra;
if (incore(&vp->v_bufobj, rabn) == NULL) {
rabp = nfs_getcacheblk(vp, rabn, biosize, td);
if (!rabp) {
error = nfs_sigintr(nmp, td);
return (error ? error : 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(nmp, rabp, cred, td)) {
rabp->b_flags |= B_INVAL;
rabp->b_ioflags |= BIO_ERROR;
vfs_unbusy_pages(rabp);
brelse(rabp);
break;
}
} else {
brelse(rabp);
}
}
}
}
/* Note that bcount is *not* DEV_BSIZE aligned. */
bcount = biosize;
if ((off_t)lbn * biosize >= nsize) {
bcount = 0;
} else if ((off_t)(lbn + 1) * biosize > nsize) {
bcount = nsize - (off_t)lbn * biosize;
}
bp = nfs_getcacheblk(vp, lbn, bcount, td);
if (!bp) {
error = nfs_sigintr(nmp, td);
return (error ? error : 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(vp, 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) {
error = nfs_sigintr(nmp, td);
return (error ? error : EINTR);
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(vp, 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) {
error = nfs_sigintr(nmp, td);
return (error ? error : EINTR);
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(vp, bp, cred, td);
if (error) {
brelse(bp);
}
while (error == NFSERR_BAD_COOKIE) {
(nmp->nm_rpcops->nr_invaldir)(vp);
error = nfs_vinvalbuf(vp, 0, 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) {
error = nfs_sigintr(nmp, td);
return (error ? error : EINTR);
}
if ((bp->b_flags & B_CACHE) == 0) {
bp->b_iocmd = BIO_READ;
vfs_busy_pages(bp, 0);
error = nfs_doio(vp, 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->v_bufobj, 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(nmp, 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:
nfs_printf(" nfs_bioread: type %x unexpected\n", vp->v_type);
bp = NULL;
break;
};
if (n > 0) {
error = uiomove(bp->b_data + on, (int)n, uio);
}
if (vp->v_type == VLNK)
n = 0;
if (bp != NULL)
brelse(bp);
} while (error == 0 && uio->uio_resid > 0 && n > 0);
return (error);
}
/*
* The NFS write path cannot handle iovecs with len > 1. So we need to
* break up iovecs accordingly (restricting them to wsize).
* For the SYNC case, we can do this with 1 copy (user buffer -> mbuf).
* For the ASYNC case, 2 copies are needed. The first a copy from the
* user buffer to a staging buffer and then a second copy from the staging
* buffer to mbufs. This can be optimized by copying from the user buffer
* directly into mbufs and passing the chain down, but that requires a
* fair amount of re-working of the relevant codepaths (and can be done
* later).
*/
static int
nfs_directio_write(vp, uiop, cred, ioflag)
struct vnode *vp;
struct uio *uiop;
struct ucred *cred;
int ioflag;
{
int error;
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
struct thread *td = uiop->uio_td;
int size;
int wsize;
mtx_lock(&nmp->nm_mtx);
wsize = nmp->nm_wsize;
mtx_unlock(&nmp->nm_mtx);
if (ioflag & IO_SYNC) {
int iomode, must_commit;
struct uio uio;
struct iovec iov;
do_sync:
while (uiop->uio_resid > 0) {
size = min(uiop->uio_resid, wsize);
size = min(uiop->uio_iov->iov_len, size);
iov.iov_base = uiop->uio_iov->iov_base;
iov.iov_len = size;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_offset = uiop->uio_offset;
uio.uio_resid = size;
uio.uio_segflg = UIO_USERSPACE;
uio.uio_rw = UIO_WRITE;
uio.uio_td = td;
iomode = NFSV3WRITE_FILESYNC;
error = (nmp->nm_rpcops->nr_writerpc)(vp, &uio, cred,
&iomode, &must_commit);
KASSERT((must_commit == 0),
("nfs_directio_write: Did not commit write"));
if (error)
return (error);
uiop->uio_offset += size;
uiop->uio_resid -= size;
if (uiop->uio_iov->iov_len <= size) {
uiop->uio_iovcnt--;
uiop->uio_iov++;
} else {
uiop->uio_iov->iov_base =
(char *)uiop->uio_iov->iov_base + size;
uiop->uio_iov->iov_len -= size;
}
}
} else {
struct uio *t_uio;
struct iovec *t_iov;
struct buf *bp;
/*
* Break up the write into blocksize chunks and hand these
* over to nfsiod's for write back.
* Unfortunately, this incurs a copy of the data. Since
* the user could modify the buffer before the write is
* initiated.
*
* The obvious optimization here is that one of the 2 copies
* in the async write path can be eliminated by copying the
* data here directly into mbufs and passing the mbuf chain
* down. But that will require a fair amount of re-working
* of the code and can be done if there's enough interest
* in NFS directio access.
*/
while (uiop->uio_resid > 0) {
size = min(uiop->uio_resid, wsize);
size = min(uiop->uio_iov->iov_len, size);
bp = getpbuf(&nfs_pbuf_freecnt);
t_uio = malloc(sizeof(struct uio), M_NFSDIRECTIO, M_WAITOK);
t_iov = malloc(sizeof(struct iovec), M_NFSDIRECTIO, M_WAITOK);
t_iov->iov_base = malloc(size, M_NFSDIRECTIO, M_WAITOK);
t_iov->iov_len = size;
t_uio->uio_iov = t_iov;
t_uio->uio_iovcnt = 1;
t_uio->uio_offset = uiop->uio_offset;
t_uio->uio_resid = size;
t_uio->uio_segflg = UIO_SYSSPACE;
t_uio->uio_rw = UIO_WRITE;
t_uio->uio_td = td;
bcopy(uiop->uio_iov->iov_base, t_iov->iov_base, size);
bp->b_flags |= B_DIRECT;
bp->b_iocmd = BIO_WRITE;
if (cred != NOCRED) {
crhold(cred);
bp->b_wcred = cred;
} else
bp->b_wcred = NOCRED;
bp->b_caller1 = (void *)t_uio;
bp->b_vp = vp;
error = nfs_asyncio(nmp, bp, NOCRED, td);
if (error) {
free(t_iov->iov_base, M_NFSDIRECTIO);
free(t_iov, M_NFSDIRECTIO);
free(t_uio, M_NFSDIRECTIO);
bp->b_vp = NULL;
relpbuf(bp, &nfs_pbuf_freecnt);
if (error == EINTR)
return (error);
goto do_sync;
}
uiop->uio_offset += size;
uiop->uio_resid -= size;
if (uiop->uio_iov->iov_len <= size) {
uiop->uio_iovcnt--;
uiop->uio_iov++;
} else {
uiop->uio_iov->iov_base =
(char *)uiop->uio_iov->iov_base + size;
uiop->uio_iov->iov_len -= size;
}
}
}
return (0);
}
/*
* 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;
KASSERT(uio->uio_rw == UIO_WRITE, ("nfs_write mode"));
KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_td == curthread,
("nfs_write proc"));
if (vp->v_type != VREG)
return (EIO);
mtx_lock(&np->n_mtx);
if (np->n_flag & NWRITEERR) {
np->n_flag &= ~NWRITEERR;
mtx_unlock(&np->n_mtx);
return (np->n_error);
} else
mtx_unlock(&np->n_mtx);
mtx_lock(&nmp->nm_mtx);
if ((nmp->nm_flag & NFSMNT_NFSV3) != 0 &&
(nmp->nm_state & NFSSTA_GOTFSINFO) == 0) {
mtx_unlock(&nmp->nm_mtx);
(void)nfs_fsinfo(nmp, vp, cred, td);
} else
mtx_unlock(&nmp->nm_mtx);
/*
* Synchronously flush pending buffers if we are in synchronous
* mode or if we are appending.
*/
if (ioflag & (IO_APPEND | IO_SYNC)) {
mtx_lock(&np->n_mtx);
if (np->n_flag & NMODIFIED) {
mtx_unlock(&np->n_mtx);
#ifdef notyet /* Needs matching nonblock semantics elsewhere, too. */
/*
* Require non-blocking, synchronous writes to
* dirty files to inform the program it needs
* to fsync(2) explicitly.
*/
if (ioflag & IO_NDELAY)
return (EAGAIN);
#endif
flush_and_restart:
np->n_attrstamp = 0;
KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
error = nfs_vinvalbuf(vp, V_SAVE, td, 1);
if (error)
return (error);
} else
mtx_unlock(&np->n_mtx);
}
/*
* If IO_APPEND then load uio_offset. We restart here if we cannot
* get the append lock.
*/
if (ioflag & IO_APPEND) {
np->n_attrstamp = 0;
KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
error = VOP_GETATTR(vp, &vattr, cred);
if (error)
return (error);
mtx_lock(&np->n_mtx);
uio->uio_offset = np->n_size;
mtx_unlock(&np->n_mtx);
}
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);
if (nfs_directio_enable && (ioflag & IO_DIRECT) && vp->v_type == VREG)
return nfs_directio_write(vp, uio, cred, ioflag);
/*
* 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 (vn_rlimit_fsize(vp, uio, td))
return (EFBIG);
biosize = vp->v_mount->mnt_stat.f_iosize;
/*
* Find all of this file's B_NEEDCOMMIT buffers. If our writes
* would exceed the local maximum per-file write commit size when
* combined with those, we must decide whether to flush,
* go synchronous, or return error. We don't bother checking
* IO_UNIT -- we just make all writes atomic anyway, as there's
* no point optimizing for something that really won't ever happen.
*/
if (!(ioflag & IO_SYNC)) {
int nflag;
mtx_lock(&np->n_mtx);
nflag = np->n_flag;
mtx_unlock(&np->n_mtx);
int needrestart = 0;
if (nmp->nm_wcommitsize < uio->uio_resid) {
/*
* If this request could not possibly be completed
* without exceeding the maximum outstanding write
* commit size, see if we can convert it into a
* synchronous write operation.
*/
if (ioflag & IO_NDELAY)
return (EAGAIN);
ioflag |= IO_SYNC;
if (nflag & NMODIFIED)
needrestart = 1;
} else if (nflag & NMODIFIED) {
int wouldcommit = 0;
BO_LOCK(&vp->v_bufobj);
if (vp->v_bufobj.bo_dirty.bv_cnt != 0) {
TAILQ_FOREACH(bp, &vp->v_bufobj.bo_dirty.bv_hd,
b_bobufs) {
if (bp->b_flags & B_NEEDCOMMIT)
wouldcommit += bp->b_bcount;
}
}
BO_UNLOCK(&vp->v_bufobj);
/*
* Since we're not operating synchronously and
* bypassing the buffer cache, we are in a commit
* and holding all of these buffers whether
* transmitted or not. If not limited, this
* will lead to the buffer cache deadlocking,
* as no one else can flush our uncommitted buffers.
*/
wouldcommit += uio->uio_resid;
/*
* If we would initially exceed the maximum
* outstanding write commit size, flush and restart.
*/
if (wouldcommit > nmp->nm_wcommitsize)
needrestart = 1;
}
if (needrestart)
goto flush_and_restart;
}
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.
*/
mtx_lock(&np->n_mtx);
if (uio->uio_offset == np->n_size && n) {
mtx_unlock(&np->n_mtx);
/*
* 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;
mtx_lock(&np->n_mtx);
np->n_size = uio->uio_offset + n;
np->n_flag |= NMODIFIED;
vnode_pager_setsize(vp, np->n_size);
mtx_unlock(&np->n_mtx);
save = bp->b_flags & B_CACHE;
bcount += n;
allocbuf(bp, bcount);
bp->b_flags |= save;
}
} 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;
}
mtx_unlock(&np->n_mtx);
bp = nfs_getcacheblk(vp, lbn, bcount, td);
mtx_lock(&np->n_mtx);
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);
}
mtx_unlock(&np->n_mtx);
}
if (!bp) {
error = nfs_sigintr(nmp, td);
if (!error)
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(vp, bp, cred, td);
if (error) {
brelse(bp);
break;
}
}
if (bp->b_wcred == NOCRED)
bp->b_wcred = crhold(cred);
mtx_lock(&np->n_mtx);
np->n_flag |= NMODIFIED;
mtx_unlock(&np->n_mtx);
/*
* 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) {
nfs_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_valid(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, NULL);
} else {
bdwrite(bp);
}
} while (uio->uio_resid > 0 && n > 0);
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) {
sigset_t oldset;
nfs_set_sigmask(td, &oldset);
bp = getblk(vp, bn, size, NFS_PCATCH, 0, 0);
nfs_restore_sigmask(td, &oldset);
while (bp == NULL) {
if (nfs_sigintr(nmp, 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 thread *td, int intrflg)
{
struct nfsnode *np = VTONFS(vp);
struct nfsmount *nmp = VFSTONFS(vp->v_mount);
int error = 0, slpflag, slptimeo;
int old_lock = 0;
ASSERT_VOP_LOCKED(vp, "nfs_vinvalbuf");
if ((nmp->nm_flag & NFSMNT_INT) == 0)
intrflg = 0;
if (intrflg) {
slpflag = NFS_PCATCH;
slptimeo = 2 * hz;
} else {
slpflag = 0;
slptimeo = 0;
}
old_lock = nfs_upgrade_vnlock(vp);
if (vp->v_iflag & VI_DOOMED) {
/*
* Since vgonel() uses the generic vinvalbuf() to flush
* dirty buffers and it does not call this function, it
* is safe to just return OK when VI_DOOMED is set.
*/
nfs_downgrade_vnlock(vp, old_lock);
return (0);
}
/*
* Now, flush as required.
*/
if ((flags & V_SAVE) && (vp->v_bufobj.bo_object != NULL)) {
VM_OBJECT_LOCK(vp->v_bufobj.bo_object);
vm_object_page_clean(vp->v_bufobj.bo_object, 0, 0, OBJPC_SYNC);
VM_OBJECT_UNLOCK(vp->v_bufobj.bo_object);
/*
* If the page clean was interrupted, fail the invalidation.
* Not doing so, we run the risk of losing dirty pages in the
* vinvalbuf() call below.
*/
if (intrflg && (error = nfs_sigintr(nmp, td)))
goto out;
}
error = vinvalbuf(vp, flags, slpflag, 0);
while (error) {
if (intrflg && (error = nfs_sigintr(nmp, td)))
goto out;
error = vinvalbuf(vp, flags, 0, slptimeo);
}
mtx_lock(&np->n_mtx);
if (np->n_directio_asyncwr == 0)
np->n_flag &= ~NMODIFIED;
mtx_unlock(&np->n_mtx);
out:
nfs_downgrade_vnlock(vp, old_lock);
return error;
}
/*
* 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 nfsmount *nmp, struct buf *bp, struct ucred *cred, struct thread *td)
{
int iod;
int gotiod;
int slpflag = 0;
int slptimeo = 0;
int error, error2;
/*
* 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).
*/
mtx_lock(&nfs_iod_mtx);
if (bp->b_iocmd == BIO_WRITE && (bp->b_flags & B_NEEDCOMMIT) &&
(nmp->nm_bufqiods > nfs_numasync / 2)) {
mtx_unlock(&nfs_iod_mtx);
return(EIO);
}
again:
if (nmp->nm_flag & NFSMNT_INT)
slpflag = NFS_PCATCH;
gotiod = FALSE;
/*
* Find a free iod to process this request.
*/
for (iod = 0; iod < nfs_numasync; iod++)
if (nfs_iodwant[iod] == NFSIOD_AVAILABLE) {
gotiod = TRUE;
break;
}
/*
* Try to create one if none are free.
*/
if (!gotiod)
nfs_nfsiodnew();
else {
/*
* 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] = NFSIOD_NOT_AVAILABLE;
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 = nfs_msleep(td, &nmp->nm_bufq, &nfs_iod_mtx,
slpflag | PRIBIO,
"nfsaio", slptimeo);
if (error) {
error2 = nfs_sigintr(nmp, td);
if (error2) {
mtx_unlock(&nfs_iod_mtx);
return (error2);
}
if (slpflag == NFS_PCATCH) {
slpflag = 0;
slptimeo = 2 * hz;
}
}
/*
* We might have lost our iod while sleeping,
* so check and loop if nescessary.
*/
goto again;
}
/* We might have lost our nfsiod */
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 {
if (bp->b_wcred == NOCRED && cred != NOCRED)
bp->b_wcred = crhold(cred);
}
if (bp->b_flags & B_REMFREE)
bremfreef(bp);
BUF_KERNPROC(bp);
TAILQ_INSERT_TAIL(&nmp->nm_bufq, bp, b_freelist);
nmp->nm_bufqlen++;
if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
mtx_lock(&(VTONFS(bp->b_vp))->n_mtx);
VTONFS(bp->b_vp)->n_flag |= NMODIFIED;
VTONFS(bp->b_vp)->n_directio_asyncwr++;
mtx_unlock(&(VTONFS(bp->b_vp))->n_mtx);
}
mtx_unlock(&nfs_iod_mtx);
return (0);
}
mtx_unlock(&nfs_iod_mtx);
/*
* 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);
}
void
nfs_doio_directwrite(struct buf *bp)
{
int iomode, must_commit;
struct uio *uiop = (struct uio *)bp->b_caller1;
char *iov_base = uiop->uio_iov->iov_base;
struct nfsmount *nmp = VFSTONFS(bp->b_vp->v_mount);
iomode = NFSV3WRITE_FILESYNC;
uiop->uio_td = NULL; /* NULL since we're in nfsiod */
(nmp->nm_rpcops->nr_writerpc)(bp->b_vp, uiop, bp->b_wcred, &iomode, &must_commit);
KASSERT((must_commit == 0), ("nfs_doio_directwrite: Did not commit write"));
free(iov_base, M_NFSDIRECTIO);
free(uiop->uio_iov, M_NFSDIRECTIO);
free(uiop, M_NFSDIRECTIO);
if ((bp->b_flags & B_DIRECT) && bp->b_iocmd == BIO_WRITE) {
struct nfsnode *np = VTONFS(bp->b_vp);
mtx_lock(&np->n_mtx);
np->n_directio_asyncwr--;
if (np->n_directio_asyncwr == 0) {
VTONFS(bp->b_vp)->n_flag &= ~NMODIFIED;
if ((np->n_flag & NFSYNCWAIT)) {
np->n_flag &= ~NFSYNCWAIT;
wakeup((caddr_t)&np->n_directio_asyncwr);
}
}
mtx_unlock(&np->n_mtx);
}
bp->b_vp = NULL;
relpbuf(bp, &nfs_pbuf_freecnt);
}
/*
* Do an I/O operation to/from a cache block. This may be called
* synchronously or from an nfsiod.
*/
int
nfs_doio(struct vnode *vp, struct buf *bp, struct ucred *cr, struct thread *td)
{
struct uio *uiop;
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;
uint8_t iocmd;
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));
iocmd = bp->b_iocmd;
if (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)) {
mtx_lock(&np->n_mtx);
if (NFS_TIMESPEC_COMPARE(&np->n_mtime, &np->n_vattr.va_mtime)) {
mtx_unlock(&np->n_mtx);
PROC_LOCK(p);
killproc(p, "text file modification");
PROC_UNLOCK(p);
} else
mtx_unlock(&np->n_mtx);
}
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_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:
nfs_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;
retv = (nmp->nm_rpcops->nr_commit)(
vp, off, bp->b_dirtyend-bp->b_dirtyoff,
bp->b_wcred, td);
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(vp->v_mount);
}
}
/*
* Setup for actual write
*/
mtx_lock(&np->n_mtx);
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;
mtx_unlock(&np->n_mtx);
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;
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);
}
/*
* 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
*
* The logic below breaks up errors into recoverable and
* unrecoverable. For the former, we clear B_INVAL|B_NOCACHE
* and keep the buffer around for potential write retries.
* For the latter (eg ESTALE), we toss the buffer away (B_INVAL)
* and save the error in the nfsnode. This is less than ideal
* but necessary. Keeping such buffers around could potentially
* cause buffer exhaustion eventually (they can never be written
* out, so will get constantly be re-dirtied). It also causes
* all sorts of vfs panics. For non-recoverable write errors,
* also invalidate the attrcache, so we'll be forced to go over
* the wire for this object, returning an error to user on next
* call (most of the time).
*/
if (error == EINTR || error == EIO || error == ETIMEDOUT
|| (!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_flags |= B_INVAL;
bp->b_error = np->n_error = error;
mtx_lock(&np->n_mtx);
np->n_flag |= NWRITEERR;
np->n_attrstamp = 0;
KDTRACE_NFS_ATTRCACHE_FLUSH_DONE(vp);
mtx_unlock(&np->n_mtx);
}
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;
int biosize = vp->v_mount->mnt_stat.f_iosize;
int error = 0;
mtx_lock(&np->n_mtx);
tsize = np->n_size;
np->n_size = nsize;
mtx_unlock(&np->n_mtx);
if (nsize < 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)
return EINTR;
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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