freebsd-dev/sys/nfsclient/nfs_socket.c
Ian Dowse 1278d57acd Permit NFS filesystems to be forcibly unmounted when the server is
down, even if there are hung processes and the mount is non-
interruptible.

This works by having nfs_unmount call a new function nfs_nmcancelreqs()
in the FORCECLOSE case. It scans the list of outstanding requests
and marks as interrupted any requests belonging to the specified
mount. Then it waits up to 30 seconds for all requests to terminate.
A few other changes are necessary to support this:
- Unconditionally set a socket timeout so that even hard mounts
  are guaranteed to occasionally check the R_SOFTTERM flag on
  requests. For hard mounts this flag can only be set by
  nfs_nmcancelreqs().
- Reject requests on a mount that is currently being unmounted.
- Never grant the receive lock to a request that has been cancelled.

This should also avoid an old problem where a forced NFS unmount
could cause a crash; it occurred when a VOP on an unlocked vnode
(usually VOP_GETATTR) was in progress at the time of the forced
unmount.
2002-01-02 00:41:26 +00:00

1410 lines
36 KiB
C

/*
* Copyright (c) 1989, 1991, 1993, 1995
* 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_socket.c 8.5 (Berkeley) 3/30/95
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Socket operations for use by nfs
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/signalvar.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vnode.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfsclient/nfs.h>
#include <nfs/xdr_subs.h>
#include <nfsclient/nfsm_subs.h>
#include <nfsclient/nfsmount.h>
#include <nfsclient/nfsnode.h>
#define TRUE 1
#define FALSE 0
/*
* Estimate rto for an nfs rpc sent via. an unreliable datagram.
* Use the mean and mean deviation of rtt for the appropriate type of rpc
* for the frequent rpcs and a default for the others.
* The justification for doing "other" this way is that these rpcs
* happen so infrequently that timer est. would probably be stale.
* Also, since many of these rpcs are
* non-idempotent, a conservative timeout is desired.
* getattr, lookup - A+2D
* read, write - A+4D
* other - nm_timeo
*/
#define NFS_RTO(n, t) \
((t) == 0 ? (n)->nm_timeo : \
((t) < 3 ? \
(((((n)->nm_srtt[t-1] + 3) >> 2) + (n)->nm_sdrtt[t-1] + 1) >> 1) : \
((((n)->nm_srtt[t-1] + 7) >> 3) + (n)->nm_sdrtt[t-1] + 1)))
#define NFS_SRTT(r) (r)->r_nmp->nm_srtt[proct[(r)->r_procnum] - 1]
#define NFS_SDRTT(r) (r)->r_nmp->nm_sdrtt[proct[(r)->r_procnum] - 1]
/*
* Defines which timer to use for the procnum.
* 0 - default
* 1 - getattr
* 2 - lookup
* 3 - read
* 4 - write
*/
static int proct[NFS_NPROCS] = {
0, 1, 0, 2, 1, 3, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 3, 3, 0, 0, 0, 0, 0,
};
static int nfs_realign_test;
static int nfs_realign_count;
static int nfs_bufpackets = 4;
SYSCTL_DECL(_vfs_nfs);
SYSCTL_INT(_vfs_nfs, OID_AUTO, realign_test, CTLFLAG_RW, &nfs_realign_test, 0, "");
SYSCTL_INT(_vfs_nfs, OID_AUTO, realign_count, CTLFLAG_RW, &nfs_realign_count, 0, "");
SYSCTL_INT(_vfs_nfs, OID_AUTO, bufpackets, CTLFLAG_RW, &nfs_bufpackets, 0, "");
/*
* There is a congestion window for outstanding rpcs maintained per mount
* point. The cwnd size is adjusted in roughly the way that:
* Van Jacobson, Congestion avoidance and Control, In "Proceedings of
* SIGCOMM '88". ACM, August 1988.
* describes for TCP. The cwnd size is chopped in half on a retransmit timeout
* and incremented by 1/cwnd when each rpc reply is received and a full cwnd
* of rpcs is in progress.
* (The sent count and cwnd are scaled for integer arith.)
* Variants of "slow start" were tried and were found to be too much of a
* performance hit (ave. rtt 3 times larger),
* I suspect due to the large rtt that nfs rpcs have.
*/
#define NFS_CWNDSCALE 256
#define NFS_MAXCWND (NFS_CWNDSCALE * 32)
#define NFS_NBACKOFF 8
static int nfs_backoff[NFS_NBACKOFF] = { 2, 4, 8, 16, 32, 64, 128, 256, };
struct callout_handle nfs_timer_handle;
static int nfs_msg(struct thread *, char *, char *);
static int nfs_rcvlock(struct nfsreq *);
static void nfs_rcvunlock(struct nfsreq *);
static void nfs_realign(struct mbuf **pm, int hsiz);
static int nfs_receive(struct nfsreq *rep, struct sockaddr **aname,
struct mbuf **mp);
static int nfs_reply(struct nfsreq *);
static void nfs_softterm(struct nfsreq *rep);
static int nfs_reconnect(struct nfsreq *rep);
/*
* Initialize sockets and congestion for a new NFS connection.
* We do not free the sockaddr if error.
*/
int
nfs_connect(struct nfsmount *nmp, struct nfsreq *rep)
{
struct socket *so;
int s, error, rcvreserve, sndreserve;
int pktscale;
struct sockaddr *saddr;
struct sockaddr_in *sin;
struct thread *td = thread0; /* only used for socreate and sobind */
nmp->nm_so = (struct socket *)0;
saddr = nmp->nm_nam;
error = socreate(saddr->sa_family, &nmp->nm_so, nmp->nm_sotype,
nmp->nm_soproto, nmp->nm_cred, td);
if (error)
goto bad;
so = nmp->nm_so;
nmp->nm_soflags = so->so_proto->pr_flags;
/*
* Some servers require that the client port be a reserved port number.
*/
if (saddr->sa_family == AF_INET && (nmp->nm_flag & NFSMNT_RESVPORT)) {
struct sockopt sopt;
int ip;
struct sockaddr_in ssin;
bzero(&sopt, sizeof sopt);
ip = IP_PORTRANGE_LOW;
sopt.sopt_dir = SOPT_SET;
sopt.sopt_level = IPPROTO_IP;
sopt.sopt_name = IP_PORTRANGE;
sopt.sopt_val = (void *)&ip;
sopt.sopt_valsize = sizeof(ip);
sopt.sopt_td = NULL;
error = sosetopt(so, &sopt);
if (error)
goto bad;
bzero(&ssin, sizeof ssin);
sin = &ssin;
sin->sin_len = sizeof (struct sockaddr_in);
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = INADDR_ANY;
sin->sin_port = htons(0);
error = sobind(so, (struct sockaddr *)sin, td);
if (error)
goto bad;
bzero(&sopt, sizeof sopt);
ip = IP_PORTRANGE_DEFAULT;
sopt.sopt_dir = SOPT_SET;
sopt.sopt_level = IPPROTO_IP;
sopt.sopt_name = IP_PORTRANGE;
sopt.sopt_val = (void *)&ip;
sopt.sopt_valsize = sizeof(ip);
sopt.sopt_td = NULL;
error = sosetopt(so, &sopt);
if (error)
goto bad;
}
/*
* Protocols that do not require connections may be optionally left
* unconnected for servers that reply from a port other than NFS_PORT.
*/
if (nmp->nm_flag & NFSMNT_NOCONN) {
if (nmp->nm_soflags & PR_CONNREQUIRED) {
error = ENOTCONN;
goto bad;
}
} else {
error = soconnect(so, nmp->nm_nam, td);
if (error)
goto bad;
/*
* Wait for the connection to complete. Cribbed from the
* connect system call but with the wait timing out so
* that interruptible mounts don't hang here for a long time.
*/
s = splnet();
while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
(void) tsleep((caddr_t)&so->so_timeo, PSOCK,
"nfscon", 2 * hz);
if ((so->so_state & SS_ISCONNECTING) &&
so->so_error == 0 && rep &&
(error = nfs_sigintr(nmp, rep,
(rep->r_td ? rep->r_td->td_proc : NULL))) != 0){
so->so_state &= ~SS_ISCONNECTING;
splx(s);
goto bad;
}
}
if (so->so_error) {
error = so->so_error;
so->so_error = 0;
splx(s);
goto bad;
}
splx(s);
}
so->so_rcv.sb_timeo = 5 * hz;
so->so_snd.sb_timeo = 5 * hz;
/*
* Get buffer reservation size from sysctl, but impose reasonable
* limits.
*/
pktscale = nfs_bufpackets;
if (pktscale < 2)
pktscale = 2;
if (pktscale > 64)
pktscale = 64;
if (nmp->nm_sotype == SOCK_DGRAM) {
sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR) * pktscale;
rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
NFS_MAXPKTHDR) * pktscale;
} else if (nmp->nm_sotype == SOCK_SEQPACKET) {
sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR) * pktscale;
rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
NFS_MAXPKTHDR) * pktscale;
} else {
if (nmp->nm_sotype != SOCK_STREAM)
panic("nfscon sotype");
if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
struct sockopt sopt;
int val;
bzero(&sopt, sizeof sopt);
sopt.sopt_level = SOL_SOCKET;
sopt.sopt_name = SO_KEEPALIVE;
sopt.sopt_val = &val;
sopt.sopt_valsize = sizeof val;
val = 1;
sosetopt(so, &sopt);
}
if (so->so_proto->pr_protocol == IPPROTO_TCP) {
struct sockopt sopt;
int val;
bzero(&sopt, sizeof sopt);
sopt.sopt_level = IPPROTO_TCP;
sopt.sopt_name = TCP_NODELAY;
sopt.sopt_val = &val;
sopt.sopt_valsize = sizeof val;
val = 1;
sosetopt(so, &sopt);
}
sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR +
sizeof (u_int32_t)) * pktscale;
rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR +
sizeof (u_int32_t)) * pktscale;
}
error = soreserve(so, sndreserve, rcvreserve);
if (error)
goto bad;
so->so_rcv.sb_flags |= SB_NOINTR;
so->so_snd.sb_flags |= SB_NOINTR;
/* Initialize other non-zero congestion variables */
nmp->nm_srtt[0] = nmp->nm_srtt[1] = nmp->nm_srtt[2] =
nmp->nm_srtt[3] = (NFS_TIMEO << 3);
nmp->nm_sdrtt[0] = nmp->nm_sdrtt[1] = nmp->nm_sdrtt[2] =
nmp->nm_sdrtt[3] = 0;
nmp->nm_cwnd = NFS_MAXCWND / 2; /* Initial send window */
nmp->nm_sent = 0;
nmp->nm_timeouts = 0;
return (0);
bad:
nfs_disconnect(nmp);
return (error);
}
/*
* Reconnect routine:
* Called when a connection is broken on a reliable protocol.
* - clean up the old socket
* - nfs_connect() again
* - set R_MUSTRESEND for all outstanding requests on mount point
* If this fails the mount point is DEAD!
* nb: Must be called with the nfs_sndlock() set on the mount point.
*/
static int
nfs_reconnect(struct nfsreq *rep)
{
struct nfsreq *rp;
struct nfsmount *nmp = rep->r_nmp;
int error;
nfs_disconnect(nmp);
while ((error = nfs_connect(nmp, rep)) != 0) {
if (error == EINTR || error == ERESTART)
return (EINTR);
(void) tsleep((caddr_t)&lbolt, PSOCK, "nfscon", 0);
}
/*
* Loop through outstanding request list and fix up all requests
* on old socket.
*/
TAILQ_FOREACH(rp, &nfs_reqq, r_chain) {
if (rp->r_nmp == nmp)
rp->r_flags |= R_MUSTRESEND;
}
return (0);
}
/*
* NFS disconnect. Clean up and unlink.
*/
void
nfs_disconnect(struct nfsmount *nmp)
{
struct socket *so;
if (nmp->nm_so) {
so = nmp->nm_so;
nmp->nm_so = (struct socket *)0;
soshutdown(so, 2);
soclose(so);
}
}
void
nfs_safedisconnect(struct nfsmount *nmp)
{
struct nfsreq dummyreq;
bzero(&dummyreq, sizeof(dummyreq));
dummyreq.r_nmp = nmp;
nfs_rcvlock(&dummyreq);
nfs_disconnect(nmp);
nfs_rcvunlock(&dummyreq);
}
/*
* This is the nfs send routine. For connection based socket types, it
* must be called with an nfs_sndlock() on the socket.
* - return EINTR if the RPC is terminated, 0 otherwise
* - set R_MUSTRESEND if the send fails for any reason
* - do any cleanup required by recoverable socket errors (?)
*/
int
nfs_send(struct socket *so, struct sockaddr *nam, struct mbuf *top,
struct nfsreq *rep)
{
struct sockaddr *sendnam;
int error, soflags, flags;
KASSERT(rep, ("nfs_send: called with rep == NULL"));
if (rep->r_flags & R_SOFTTERM) {
m_freem(top);
return (EINTR);
}
if ((so = rep->r_nmp->nm_so) == NULL) {
rep->r_flags |= R_MUSTRESEND;
m_freem(top);
return (0);
}
rep->r_flags &= ~R_MUSTRESEND;
soflags = rep->r_nmp->nm_soflags;
if ((soflags & PR_CONNREQUIRED) || (so->so_state & SS_ISCONNECTED))
sendnam = (struct sockaddr *)0;
else
sendnam = nam;
if (so->so_type == SOCK_SEQPACKET)
flags = MSG_EOR;
else
flags = 0;
error = so->so_proto->pr_usrreqs->pru_sosend(so, sendnam, 0, top, 0,
flags, curthread /*XXX*/);
if (error == ENOBUFS && so->so_type == SOCK_DGRAM) {
error = 0;
rep->r_flags |= R_MUSTRESEND;
}
if (error) {
log(LOG_INFO, "nfs send error %d for server %s\n", error,
rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
/*
* Deal with errors for the client side.
*/
if (rep->r_flags & R_SOFTTERM)
error = EINTR;
else
rep->r_flags |= R_MUSTRESEND;
/*
* Handle any recoverable (soft) socket errors here. (?)
*/
if (error != EINTR && error != ERESTART &&
error != EWOULDBLOCK && error != EPIPE)
error = 0;
}
return (error);
}
/*
* Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
* done by soreceive(), but for SOCK_STREAM we must deal with the Record
* Mark and consolidate the data into a new mbuf list.
* nb: Sometimes TCP passes the data up to soreceive() in long lists of
* small mbufs.
* For SOCK_STREAM we must be very careful to read an entire record once
* we have read any of it, even if the system call has been interrupted.
*/
static int
nfs_receive(struct nfsreq *rep, struct sockaddr **aname, struct mbuf **mp)
{
struct socket *so;
struct uio auio;
struct iovec aio;
struct mbuf *m;
struct mbuf *control;
u_int32_t len;
struct sockaddr **getnam;
int error, sotype, rcvflg;
struct thread *td = curthread; /* XXX */
/*
* Set up arguments for soreceive()
*/
*mp = (struct mbuf *)0;
*aname = (struct sockaddr *)0;
sotype = rep->r_nmp->nm_sotype;
/*
* For reliable protocols, lock against other senders/receivers
* in case a reconnect is necessary.
* For SOCK_STREAM, first get the Record Mark to find out how much
* more there is to get.
* We must lock the socket against other receivers
* until we have an entire rpc request/reply.
*/
if (sotype != SOCK_DGRAM) {
error = nfs_sndlock(rep);
if (error)
return (error);
tryagain:
/*
* Check for fatal errors and resending request.
*/
/*
* Ugh: If a reconnect attempt just happened, nm_so
* would have changed. NULL indicates a failed
* attempt that has essentially shut down this
* mount point.
*/
if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
nfs_sndunlock(rep);
return (EINTR);
}
so = rep->r_nmp->nm_so;
if (!so) {
error = nfs_reconnect(rep);
if (error) {
nfs_sndunlock(rep);
return (error);
}
goto tryagain;
}
while (rep->r_flags & R_MUSTRESEND) {
m = m_copym(rep->r_mreq, 0, M_COPYALL, M_TRYWAIT);
nfsstats.rpcretries++;
error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
if (error) {
if (error == EINTR || error == ERESTART ||
(error = nfs_reconnect(rep)) != 0) {
nfs_sndunlock(rep);
return (error);
}
goto tryagain;
}
}
nfs_sndunlock(rep);
if (sotype == SOCK_STREAM) {
aio.iov_base = (caddr_t) &len;
aio.iov_len = sizeof(u_int32_t);
auio.uio_iov = &aio;
auio.uio_iovcnt = 1;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = UIO_READ;
auio.uio_offset = 0;
auio.uio_resid = sizeof(u_int32_t);
auio.uio_td = td;
do {
rcvflg = MSG_WAITALL;
error = so->so_proto->pr_usrreqs->pru_soreceive
(so, (struct sockaddr **)0, &auio,
(struct mbuf **)0, (struct mbuf **)0,
&rcvflg);
if (error == EWOULDBLOCK && rep) {
if (rep->r_flags & R_SOFTTERM)
return (EINTR);
}
} while (error == EWOULDBLOCK);
if (!error && auio.uio_resid > 0) {
/*
* Don't log a 0 byte receive; it means
* that the socket has been closed, and
* can happen during normal operation
* (forcible unmount or Solaris server).
*/
if (auio.uio_resid != sizeof (u_int32_t))
log(LOG_INFO,
"short receive (%d/%d) from nfs server %s\n",
(int)(sizeof(u_int32_t) - auio.uio_resid),
(int)sizeof(u_int32_t),
rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
error = EPIPE;
}
if (error)
goto errout;
len = ntohl(len) & ~0x80000000;
/*
* This is SERIOUS! We are out of sync with the sender
* and forcing a disconnect/reconnect is all I can do.
*/
if (len > NFS_MAXPACKET) {
log(LOG_ERR, "%s (%d) from nfs server %s\n",
"impossible packet length",
len,
rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
error = EFBIG;
goto errout;
}
auio.uio_resid = len;
do {
rcvflg = MSG_WAITALL;
error = so->so_proto->pr_usrreqs->pru_soreceive
(so, (struct sockaddr **)0,
&auio, mp, (struct mbuf **)0, &rcvflg);
} while (error == EWOULDBLOCK || error == EINTR ||
error == ERESTART);
if (!error && auio.uio_resid > 0) {
if (len != auio.uio_resid)
log(LOG_INFO,
"short receive (%d/%d) from nfs server %s\n",
len - auio.uio_resid, len,
rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
error = EPIPE;
}
} else {
/*
* NB: Since uio_resid is big, MSG_WAITALL is ignored
* and soreceive() will return when it has either a
* control msg or a data msg.
* We have no use for control msg., but must grab them
* and then throw them away so we know what is going
* on.
*/
auio.uio_resid = len = 100000000; /* Anything Big */
auio.uio_td = td;
do {
rcvflg = 0;
error = so->so_proto->pr_usrreqs->pru_soreceive
(so, (struct sockaddr **)0,
&auio, mp, &control, &rcvflg);
if (control)
m_freem(control);
if (error == EWOULDBLOCK && rep) {
if (rep->r_flags & R_SOFTTERM)
return (EINTR);
}
} while (error == EWOULDBLOCK ||
(!error && *mp == NULL && control));
if ((rcvflg & MSG_EOR) == 0)
printf("Egad!!\n");
if (!error && *mp == NULL)
error = EPIPE;
len -= auio.uio_resid;
}
errout:
if (error && error != EINTR && error != ERESTART) {
m_freem(*mp);
*mp = (struct mbuf *)0;
if (error != EPIPE)
log(LOG_INFO,
"receive error %d from nfs server %s\n",
error,
rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
error = nfs_sndlock(rep);
if (!error)
error = nfs_reconnect(rep);
if (!error)
goto tryagain;
else
nfs_sndunlock(rep);
}
} else {
if ((so = rep->r_nmp->nm_so) == NULL)
return (EACCES);
if (so->so_state & SS_ISCONNECTED)
getnam = (struct sockaddr **)0;
else
getnam = aname;
auio.uio_resid = len = 1000000;
auio.uio_td = td;
do {
rcvflg = 0;
error = so->so_proto->pr_usrreqs->pru_soreceive
(so, getnam, &auio, mp,
(struct mbuf **)0, &rcvflg);
if (error == EWOULDBLOCK &&
(rep->r_flags & R_SOFTTERM))
return (EINTR);
} while (error == EWOULDBLOCK);
len -= auio.uio_resid;
}
if (error) {
m_freem(*mp);
*mp = (struct mbuf *)0;
}
/*
* Search for any mbufs that are not a multiple of 4 bytes long
* or with m_data not longword aligned.
* These could cause pointer alignment problems, so copy them to
* well aligned mbufs.
*/
nfs_realign(mp, 5 * NFSX_UNSIGNED);
return (error);
}
/*
* Implement receipt of reply on a socket.
* We must search through the list of received datagrams matching them
* with outstanding requests using the xid, until ours is found.
*/
/* ARGSUSED */
static int
nfs_reply(struct nfsreq *myrep)
{
struct nfsreq *rep;
struct nfsmount *nmp = myrep->r_nmp;
int32_t t1;
struct mbuf *mrep, *md;
struct sockaddr *nam;
u_int32_t rxid, *tl;
caddr_t dpos;
int error;
/*
* Loop around until we get our own reply
*/
for (;;) {
/*
* Lock against other receivers so that I don't get stuck in
* sbwait() after someone else has received my reply for me.
* Also necessary for connection based protocols to avoid
* race conditions during a reconnect.
* If nfs_rcvlock() returns EALREADY, that means that
* the reply has already been recieved by another
* process and we can return immediately. In this
* case, the lock is not taken to avoid races with
* other processes.
*/
error = nfs_rcvlock(myrep);
if (error == EALREADY)
return (0);
if (error)
return (error);
/*
* Get the next Rpc reply off the socket
*/
error = nfs_receive(myrep, &nam, &mrep);
nfs_rcvunlock(myrep);
if (error) {
/*
* Ignore routing errors on connectionless protocols??
*/
if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
nmp->nm_so->so_error = 0;
if (myrep->r_flags & R_GETONEREP)
return (0);
continue;
}
return (error);
}
if (nam)
FREE(nam, M_SONAME);
/*
* Get the xid and check that it is an rpc reply
*/
md = mrep;
dpos = mtod(md, caddr_t);
tl = nfsm_dissect(u_int32_t *, 2 * NFSX_UNSIGNED);
rxid = *tl++;
if (*tl != rpc_reply) {
nfsstats.rpcinvalid++;
m_freem(mrep);
nfsmout:
if (myrep->r_flags & R_GETONEREP)
return (0);
continue;
}
/*
* Loop through the request list to match up the reply
* Iff no match, just drop the datagram
*/
TAILQ_FOREACH(rep, &nfs_reqq, r_chain) {
if (rep->r_mrep == NULL && rxid == rep->r_xid) {
/* Found it.. */
rep->r_mrep = mrep;
rep->r_md = md;
rep->r_dpos = dpos;
/*
* Update congestion window.
* Do the additive increase of
* one rpc/rtt.
*/
if (nmp->nm_cwnd <= nmp->nm_sent) {
nmp->nm_cwnd +=
(NFS_CWNDSCALE * NFS_CWNDSCALE +
(nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
if (nmp->nm_cwnd > NFS_MAXCWND)
nmp->nm_cwnd = NFS_MAXCWND;
}
if (rep->r_flags & R_SENT) {
rep->r_flags &= ~R_SENT;
nmp->nm_sent -= NFS_CWNDSCALE;
}
/*
* Update rtt using a gain of 0.125 on the mean
* and a gain of 0.25 on the deviation.
*/
if (rep->r_flags & R_TIMING) {
/*
* Since the timer resolution of
* NFS_HZ is so course, it can often
* result in r_rtt == 0. Since
* r_rtt == N means that the actual
* rtt is between N+dt and N+2-dt ticks,
* add 1.
*/
t1 = rep->r_rtt + 1;
t1 -= (NFS_SRTT(rep) >> 3);
NFS_SRTT(rep) += t1;
if (t1 < 0)
t1 = -t1;
t1 -= (NFS_SDRTT(rep) >> 2);
NFS_SDRTT(rep) += t1;
}
nmp->nm_timeouts = 0;
break;
}
}
/*
* If not matched to a request, drop it.
* If it's mine, get out.
*/
if (rep == 0) {
nfsstats.rpcunexpected++;
m_freem(mrep);
} else if (rep == myrep) {
if (rep->r_mrep == NULL)
panic("nfsreply nil");
return (0);
}
if (myrep->r_flags & R_GETONEREP)
return (0);
}
}
/*
* nfs_request - goes something like this
* - fill in request struct
* - links it into list
* - calls nfs_send() for first transmit
* - calls nfs_receive() to get reply
* - break down rpc header and return with nfs reply pointed to
* by mrep or error
* nb: always frees up mreq mbuf list
*/
/* XXX overloaded before */
#define NQ_TRYLATERDEL 15 /* Initial try later delay (sec) */
int
nfs_request(struct vnode *vp, struct mbuf *mrest, int procnum,
struct thread *td, struct ucred *cred, struct mbuf **mrp,
struct mbuf **mdp, caddr_t *dposp)
{
struct mbuf *mrep, *m2;
struct nfsreq *rep;
u_int32_t *tl;
int i;
struct nfsmount *nmp;
struct mbuf *m, *md, *mheadend;
time_t waituntil;
caddr_t dpos;
int s, error = 0, mrest_len, auth_len, auth_type;
int trylater_delay = NQ_TRYLATERDEL, trylater_cnt = 0;
u_int32_t xid;
/* Reject requests while attempting to unmount. */
if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNT) {
m_freem(mrest);
return (ESTALE);
}
nmp = VFSTONFS(vp->v_mount);
MALLOC(rep, struct nfsreq *, sizeof(struct nfsreq), M_NFSREQ, M_WAITOK);
rep->r_nmp = nmp;
rep->r_vp = vp;
rep->r_td = td;
rep->r_procnum = procnum;
i = 0;
m = mrest;
while (m) {
i += m->m_len;
m = m->m_next;
}
mrest_len = i;
/*
* Get the RPC header with authorization.
*/
auth_type = RPCAUTH_UNIX;
if (cred->cr_ngroups < 1)
panic("nfsreq nogrps");
auth_len = ((((cred->cr_ngroups - 1) > nmp->nm_numgrps) ?
nmp->nm_numgrps : (cred->cr_ngroups - 1)) << 2) +
5 * NFSX_UNSIGNED;
m = nfsm_rpchead(cred, nmp->nm_flag, procnum, auth_type, auth_len,
mrest, mrest_len, &mheadend, &xid);
/*
* For stream protocols, insert a Sun RPC Record Mark.
*/
if (nmp->nm_sotype == SOCK_STREAM) {
M_PREPEND(m, NFSX_UNSIGNED, M_TRYWAIT);
*mtod(m, u_int32_t *) = htonl(0x80000000 |
(m->m_pkthdr.len - NFSX_UNSIGNED));
}
rep->r_mreq = m;
rep->r_xid = xid;
tryagain:
if (nmp->nm_flag & NFSMNT_SOFT)
rep->r_retry = nmp->nm_retry;
else
rep->r_retry = NFS_MAXREXMIT + 1; /* past clip limit */
rep->r_rtt = rep->r_rexmit = 0;
if (proct[procnum] > 0)
rep->r_flags = R_TIMING;
else
rep->r_flags = 0;
rep->r_mrep = NULL;
/*
* Do the client side RPC.
*/
nfsstats.rpcrequests++;
/*
* Chain request into list of outstanding requests. Be sure
* to put it LAST so timer finds oldest requests first.
*/
s = splsoftclock();
TAILQ_INSERT_TAIL(&nfs_reqq, rep, r_chain);
/*
* If backing off another request or avoiding congestion, don't
* send this one now but let timer do it. If not timing a request,
* do it now.
*/
if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
(nmp->nm_flag & NFSMNT_DUMBTIMR) ||
nmp->nm_sent < nmp->nm_cwnd)) {
splx(s);
if (nmp->nm_soflags & PR_CONNREQUIRED)
error = nfs_sndlock(rep);
if (!error) {
m2 = m_copym(m, 0, M_COPYALL, M_TRYWAIT);
error = nfs_send(nmp->nm_so, nmp->nm_nam, m2, rep);
if (nmp->nm_soflags & PR_CONNREQUIRED)
nfs_sndunlock(rep);
}
if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
nmp->nm_sent += NFS_CWNDSCALE;
rep->r_flags |= R_SENT;
}
} else {
splx(s);
rep->r_rtt = -1;
}
/*
* Wait for the reply from our send or the timer's.
*/
if (!error || error == EPIPE)
error = nfs_reply(rep);
/*
* RPC done, unlink the request.
*/
s = splsoftclock();
TAILQ_REMOVE(&nfs_reqq, rep, r_chain);
splx(s);
/*
* Decrement the outstanding request count.
*/
if (rep->r_flags & R_SENT) {
rep->r_flags &= ~R_SENT; /* paranoia */
nmp->nm_sent -= NFS_CWNDSCALE;
}
/*
* If there was a successful reply and a tprintf msg.
* tprintf a response.
*/
if (!error && (rep->r_flags & R_TPRINTFMSG))
nfs_msg(rep->r_td, nmp->nm_mountp->mnt_stat.f_mntfromname,
"is alive again");
mrep = rep->r_mrep;
md = rep->r_md;
dpos = rep->r_dpos;
if (error) {
m_freem(rep->r_mreq);
free((caddr_t)rep, M_NFSREQ);
return (error);
}
/*
* break down the rpc header and check if ok
*/
tl = nfsm_dissect(u_int32_t *, 3 * NFSX_UNSIGNED);
if (*tl++ == rpc_msgdenied) {
if (*tl == rpc_mismatch)
error = EOPNOTSUPP;
else
error = EACCES;
m_freem(mrep);
m_freem(rep->r_mreq);
free((caddr_t)rep, M_NFSREQ);
return (error);
}
/*
* Just throw away any verifyer (ie: kerberos etc).
*/
i = fxdr_unsigned(int, *tl++); /* verf type */
i = fxdr_unsigned(int32_t, *tl); /* len */
if (i > 0)
nfsm_adv(nfsm_rndup(i));
tl = nfsm_dissect(u_int32_t *, NFSX_UNSIGNED);
/* 0 == ok */
if (*tl == 0) {
tl = nfsm_dissect(u_int32_t *, NFSX_UNSIGNED);
if (*tl != 0) {
error = fxdr_unsigned(int, *tl);
if ((nmp->nm_flag & NFSMNT_NFSV3) &&
error == NFSERR_TRYLATER) {
m_freem(mrep);
error = 0;
waituntil = time_second + trylater_delay;
while (time_second < waituntil)
(void) tsleep((caddr_t)&lbolt,
PSOCK, "nqnfstry", 0);
trylater_delay *= nfs_backoff[trylater_cnt];
if (trylater_cnt < NFS_NBACKOFF - 1)
trylater_cnt++;
goto tryagain;
}
/*
* If the File Handle was stale, invalidate the
* lookup cache, just in case.
*/
if (error == ESTALE)
cache_purge(vp);
if (nmp->nm_flag & NFSMNT_NFSV3) {
*mrp = mrep;
*mdp = md;
*dposp = dpos;
error |= NFSERR_RETERR;
} else
m_freem(mrep);
m_freem(rep->r_mreq);
free((caddr_t)rep, M_NFSREQ);
return (error);
}
*mrp = mrep;
*mdp = md;
*dposp = dpos;
m_freem(rep->r_mreq);
FREE((caddr_t)rep, M_NFSREQ);
return (0);
}
m_freem(mrep);
error = EPROTONOSUPPORT;
nfsmout:
m_freem(rep->r_mreq);
free((caddr_t)rep, M_NFSREQ);
return (error);
}
/*
* Nfs timer routine
* Scan the nfsreq list and retranmit any requests that have timed out
* To avoid retransmission attempts on STREAM sockets (in the future) make
* sure to set the r_retry field to 0 (implies nm_retry == 0).
*/
void
nfs_timer(void *arg)
{
struct nfsreq *rep;
struct mbuf *m;
struct socket *so;
struct nfsmount *nmp;
int timeo;
int s, error;
struct thread *td = thread0; /* XXX for credentials, will break if sleep */
s = splnet();
TAILQ_FOREACH(rep, &nfs_reqq, r_chain) {
nmp = rep->r_nmp;
if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
continue;
if (nfs_sigintr(nmp, rep,
(rep->r_td ? rep->r_td->td_proc : NULL))) {
nfs_softterm(rep);
continue;
}
if (rep->r_rtt >= 0) {
rep->r_rtt++;
if (nmp->nm_flag & NFSMNT_DUMBTIMR)
timeo = nmp->nm_timeo;
else
timeo = NFS_RTO(nmp, proct[rep->r_procnum]);
if (nmp->nm_timeouts > 0)
timeo *= nfs_backoff[nmp->nm_timeouts - 1];
if (rep->r_rtt <= timeo)
continue;
if (nmp->nm_timeouts < NFS_NBACKOFF)
nmp->nm_timeouts++;
}
/*
* Check for server not responding
*/
if ((rep->r_flags & R_TPRINTFMSG) == 0 &&
rep->r_rexmit > nmp->nm_deadthresh) {
char buf[40];
sprintf(buf, "not responding %d > %d",
rep->r_rexmit, nmp->nm_deadthresh);
nfs_msg(rep->r_td,
nmp->nm_mountp->mnt_stat.f_mntfromname,
buf /* "not responding" */);
rep->r_flags |= R_TPRINTFMSG;
}
if (rep->r_rexmit >= rep->r_retry) { /* too many */
nfsstats.rpctimeouts++;
nfs_softterm(rep);
continue;
}
if (nmp->nm_sotype != SOCK_DGRAM) {
if (++rep->r_rexmit > NFS_MAXREXMIT)
rep->r_rexmit = NFS_MAXREXMIT;
continue;
}
if ((so = nmp->nm_so) == NULL)
continue;
/*
* If there is enough space and the window allows..
* Resend it
* Set r_rtt to -1 in case we fail to send it now.
*/
rep->r_rtt = -1;
if (sbspace(&so->so_snd) >= rep->r_mreq->m_pkthdr.len &&
((nmp->nm_flag & NFSMNT_DUMBTIMR) ||
(rep->r_flags & R_SENT) ||
nmp->nm_sent < nmp->nm_cwnd) &&
(m = m_copym(rep->r_mreq, 0, M_COPYALL, M_DONTWAIT))){
if ((nmp->nm_flag & NFSMNT_NOCONN) == 0)
error = (*so->so_proto->pr_usrreqs->pru_send)
(so, 0, m, (struct sockaddr *)0,
(struct mbuf *)0, td);
else
error = (*so->so_proto->pr_usrreqs->pru_send)
(so, 0, m, nmp->nm_nam, (struct mbuf *)0,
td);
if (error) {
if (NFSIGNORE_SOERROR(nmp->nm_soflags, error))
so->so_error = 0;
} else {
/*
* Iff first send, start timing
* else turn timing off, backoff timer
* and divide congestion window by 2.
*/
if (rep->r_flags & R_SENT) {
rep->r_flags &= ~R_TIMING;
if (++rep->r_rexmit > NFS_MAXREXMIT)
rep->r_rexmit = NFS_MAXREXMIT;
nmp->nm_cwnd >>= 1;
if (nmp->nm_cwnd < NFS_CWNDSCALE)
nmp->nm_cwnd = NFS_CWNDSCALE;
nfsstats.rpcretries++;
} else {
rep->r_flags |= R_SENT;
nmp->nm_sent += NFS_CWNDSCALE;
}
rep->r_rtt = 0;
}
}
}
splx(s);
nfs_timer_handle = timeout(nfs_timer, (void *)0, nfs_ticks);
}
/*
* Mark all of an nfs mount's outstanding requests with R_SOFTTERM and
* wait for all requests to complete. This is used by forced unmounts
* to terminate any outstanding RPCs.
*/
int
nfs_nmcancelreqs(nmp)
struct nfsmount *nmp;
{
struct nfsreq *req;
int i, s;
s = splnet();
TAILQ_FOREACH(req, &nfs_reqq, r_chain) {
if (nmp != req->r_nmp || req->r_mrep != NULL ||
(req->r_flags & R_SOFTTERM))
continue;
nfs_softterm(req);
}
splx(s);
for (i = 0; i < 30; i++) {
tsleep(&lbolt, PSOCK, "nfscancel", 0);
s = splnet();
TAILQ_FOREACH(req, &nfs_reqq, r_chain) {
if (nmp == req->r_nmp)
break;
}
splx(s);
if (req == NULL)
return (0);
}
return (EBUSY);
}
/*
* Flag a request as being about to terminate (due to NFSMNT_INT/NFSMNT_SOFT).
* The nm_send count is decremented now to avoid deadlocks when the process in
* soreceive() hasn't yet managed to send its own request.
*/
static void
nfs_softterm(struct nfsreq *rep)
{
rep->r_flags |= R_SOFTTERM;
if (rep->r_flags & R_SENT) {
rep->r_nmp->nm_sent -= NFS_CWNDSCALE;
rep->r_flags &= ~R_SENT;
}
}
/*
* Test for a termination condition pending on the process.
* This is used for NFSMNT_INT mounts.
*/
int
nfs_sigintr(struct nfsmount *nmp, struct nfsreq *rep, struct proc *p)
{
sigset_t tmpset;
if (rep && (rep->r_flags & R_SOFTTERM))
return (EINTR);
if (!(nmp->nm_flag & NFSMNT_INT))
return (0);
if (p == NULL)
return (0);
tmpset = p->p_siglist;
SIGSETNAND(tmpset, p->p_sigmask);
SIGSETNAND(tmpset, p->p_sigignore);
if (SIGNOTEMPTY(p->p_siglist) && NFSINT_SIGMASK(tmpset))
return (EINTR);
return (0);
}
/*
* Lock a socket against others.
* Necessary for STREAM sockets to ensure you get an entire rpc request/reply
* and also to avoid race conditions between the processes with nfs requests
* in progress when a reconnect is necessary.
*/
int
nfs_sndlock(struct nfsreq *rep)
{
int *statep = &rep->r_nmp->nm_state;
struct thread *td;
int slpflag = 0, slptimeo = 0;
if (rep) {
td = rep->r_td;
if (rep->r_nmp->nm_flag & NFSMNT_INT)
slpflag = PCATCH;
} else
td = (struct thread *)0;
while (*statep & NFSSTA_SNDLOCK) {
if (nfs_sigintr(rep->r_nmp, rep, td ? td->td_proc : NULL))
return (EINTR);
*statep |= NFSSTA_WANTSND;
(void) tsleep((caddr_t)statep, slpflag | (PZERO - 1),
"nfsndlck", slptimeo);
if (slpflag == PCATCH) {
slpflag = 0;
slptimeo = 2 * hz;
}
}
*statep |= NFSSTA_SNDLOCK;
return (0);
}
/*
* Unlock the stream socket for others.
*/
void
nfs_sndunlock(struct nfsreq *rep)
{
int *statep = &rep->r_nmp->nm_state;
if ((*statep & NFSSTA_SNDLOCK) == 0)
panic("nfs sndunlock");
*statep &= ~NFSSTA_SNDLOCK;
if (*statep & NFSSTA_WANTSND) {
*statep &= ~NFSSTA_WANTSND;
wakeup((caddr_t)statep);
}
}
static int
nfs_rcvlock(struct nfsreq *rep)
{
int *statep = &rep->r_nmp->nm_state;
int slpflag, slptimeo = 0;
if (rep->r_nmp->nm_flag & NFSMNT_INT)
slpflag = PCATCH;
else
slpflag = 0;
while (*statep & NFSSTA_RCVLOCK) {
if (nfs_sigintr(rep->r_nmp, rep,
(rep->r_td ? rep->r_td->td_proc : NULL)))
return (EINTR);
*statep |= NFSSTA_WANTRCV;
(void) tsleep((caddr_t)statep, slpflag | (PZERO - 1), "nfsrcvlk",
slptimeo);
/*
* If our reply was recieved while we were sleeping,
* then just return without taking the lock to avoid a
* situation where a single iod could 'capture' the
* recieve lock.
*/
if (rep->r_mrep != NULL)
return (EALREADY);
if (slpflag == PCATCH) {
slpflag = 0;
slptimeo = 2 * hz;
}
}
/* Always fail if our request has been cancelled. */
if (rep != NULL && (rep->r_flags & R_SOFTTERM))
return (EINTR);
*statep |= NFSSTA_RCVLOCK;
return (0);
}
/*
* Unlock the stream socket for others.
*/
static void
nfs_rcvunlock(struct nfsreq *rep)
{
int *statep = &rep->r_nmp->nm_state;
if ((*statep & NFSSTA_RCVLOCK) == 0)
panic("nfs rcvunlock");
*statep &= ~NFSSTA_RCVLOCK;
if (*statep & NFSSTA_WANTRCV) {
*statep &= ~NFSSTA_WANTRCV;
wakeup((caddr_t)statep);
}
}
/*
* nfs_realign:
*
* Check for badly aligned mbuf data and realign by copying the unaligned
* portion of the data into a new mbuf chain and freeing the portions
* of the old chain that were replaced.
*
* We cannot simply realign the data within the existing mbuf chain
* because the underlying buffers may contain other rpc commands and
* we cannot afford to overwrite them.
*
* We would prefer to avoid this situation entirely. The situation does
* not occur with NFS/UDP and is supposed to only occassionally occur
* with TCP. Use vfs.nfs.realign_count and realign_test to check this.
*/
static void
nfs_realign(struct mbuf **pm, int hsiz)
{
struct mbuf *m;
struct mbuf *n = NULL;
int off = 0;
++nfs_realign_test;
while ((m = *pm) != NULL) {
if ((m->m_len & 0x3) || (mtod(m, intptr_t) & 0x3)) {
MGET(n, M_TRYWAIT, MT_DATA);
if (m->m_len >= MINCLSIZE) {
MCLGET(n, M_TRYWAIT);
}
n->m_len = 0;
break;
}
pm = &m->m_next;
}
/*
* If n is non-NULL, loop on m copying data, then replace the
* portion of the chain that had to be realigned.
*/
if (n != NULL) {
++nfs_realign_count;
while (m) {
m_copyback(n, off, m->m_len, mtod(m, caddr_t));
off += m->m_len;
m = m->m_next;
}
m_freem(*pm);
*pm = n;
}
}
static int
nfs_msg(struct thread *td, char *server, char *msg)
{
tprintf(td ? td->td_proc : NULL, LOG_INFO,
"nfs server %s: %s\n", server, msg);
return (0);
}