Author: kib
Date: Mon Nov 8 15:22:20 2010
New Revision: 214986
URL: http://svn.freebsd.org/changeset/base/214986
Log:
MFC r203072 (by rmacklem, to be reverted by MFC of r214026):
Fix a race that can occur when nfs nfsiod threads are being created.
MFC r212506:
Do not fork nfsiod directly from the vop methods.
MFC r214026:
Do not synchronously start the nfsiod threads at all.
Tested by: jhb
Modified:
stable/7/sys/nfsclient/nfs.h
stable/7/sys/nfsclient/nfs_bio.c
stable/7/sys/nfsclient/nfs_nfsiod.c
stable/7/sys/nfsclient/nfs_subs.c
stable/7/sys/nfsclient/nfs_vnops.c
stable/7/sys/nfsclient/nfsnode.h
Directory Properties:
stable/7/sys/ (props changed)
stable/7/sys/cddl/contrib/opensolaris/ (props changed)
stable/7/sys/contrib/dev/acpica/ (props changed)
stable/7/sys/contrib/pf/ (props changed)
Modified: stable/7/sys/nfsclient/nfs.h
==============================================================================
--- stable/7/sys/nfsclient/nfs.h Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfs.h Mon Nov 8 15:22:20 2010
(r214986)
@@ -135,6 +135,7 @@ extern struct uma_zone *nfsmount_zone;
extern struct callout nfs_callout;
extern struct nfsstats nfsstats;
extern struct mtx nfs_iod_mtx;
+extern struct task nfs_nfsiodnew_task;
extern int nfs_numasync;
extern unsigned int nfs_iodmax;
@@ -305,7 +306,8 @@ int nfs_writerpc(struct vnode *, struct
int nfs_commit(struct vnode *vp, u_quad_t offset, int cnt,
struct ucred *cred, struct thread *td);
int nfs_readdirrpc(struct vnode *, struct uio *, struct ucred *);
-int nfs_nfsiodnew(void);
+void nfs_nfsiodnew(void);
+void nfs_nfsiodnew_tq(__unused void *, int);
int nfs_asyncio(struct nfsmount *, struct buf *, struct ucred *, struct
thread *);
int nfs_doio(struct vnode *, struct buf *, struct ucred *, struct thread *);
void nfs_doio_directwrite (struct buf *);
Modified: stable/7/sys/nfsclient/nfs_bio.c
==============================================================================
--- stable/7/sys/nfsclient/nfs_bio.c Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfs_bio.c Mon Nov 8 15:22:20 2010
(r214986)
@@ -1375,7 +1375,7 @@ again:
* Find a free iod to process this request.
*/
for (iod = 0; iod < nfs_numasync; iod++)
- if (nfs_iodwant[iod]) {
+ if (nfs_iodwant[iod] == NFSIOD_AVAILABLE) {
gotiod = TRUE;
break;
}
@@ -1383,20 +1383,16 @@ again:
/*
* Try to create one if none are free.
*/
- if (!gotiod) {
- iod = nfs_nfsiodnew();
- if (iod != -1)
- gotiod = TRUE;
- }
-
- if (gotiod) {
+ 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] = NULL;
+ nfs_iodwant[iod] = NFSIOD_NOT_AVAILABLE;
nfs_iodmount[iod] = nmp;
nmp->nm_bufqiods++;
wakeup(&nfs_iodwant[iod]);
@@ -1409,7 +1405,7 @@ again:
if (!gotiod) {
if (nmp->nm_bufqiods > 0) {
NFS_DPF(ASYNCIO,
- ("nfs_asyncio: %d iods are already processing
mount %p\n",
+ ("nfs_asyncio: %d iods are already processing mount %p\n",
nmp->nm_bufqiods, nmp));
gotiod = TRUE;
}
@@ -1424,9 +1420,9 @@ again:
* 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) {
+ while (nmp->nm_bufqlen >= 2 * nfs_numasync) {
NFS_DPF(ASYNCIO,
- ("nfs_asyncio: waiting for mount %p queue to
drain\n", nmp));
+ ("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,
@@ -1434,7 +1430,7 @@ again:
if (error) {
error2 = nfs_sigintr(nmp, NULL, td);
if (error2) {
- mtx_unlock(&nfs_iod_mtx);
+ mtx_unlock(&nfs_iod_mtx);
return (error2);
}
if (slpflag == PCATCH) {
@@ -1446,17 +1442,13 @@ again:
* 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;
- }
+ 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));
+("nfs_asyncio: no iods after mount %p queue was drained, looping\n", nmp));
goto again;
}
Modified: stable/7/sys/nfsclient/nfs_nfsiod.c
==============================================================================
--- stable/7/sys/nfsclient/nfs_nfsiod.c Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfs_nfsiod.c Mon Nov 8 15:22:20 2010
(r214986)
@@ -59,6 +59,7 @@ __FBSDID("$FreeBSD$");
#include <sys/fcntl.h>
#include <sys/lockf.h>
#include <sys/mutex.h>
+#include <sys/taskqueue.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
@@ -92,6 +93,8 @@ unsigned int nfs_iodmax = 20;
/* Minimum number of nfsiod kthreads to keep as spares */
static unsigned int nfs_iodmin = 0;
+static int nfs_nfsiodnew_sync(void);
+
static int
sysctl_iodmin(SYSCTL_HANDLER_ARGS)
{
@@ -115,7 +118,7 @@ sysctl_iodmin(SYSCTL_HANDLER_ARGS)
* than the new minimum, create some more.
*/
for (i = nfs_iodmin - nfs_numasync; i > 0; i--)
- nfs_nfsiodnew();
+ nfs_nfsiodnew_sync();
out:
mtx_unlock(&nfs_iod_mtx);
return (0);
@@ -148,7 +151,7 @@ sysctl_iodmax(SYSCTL_HANDLER_ARGS)
*/
iod = nfs_numasync - 1;
for (i = 0; i < nfs_numasync - nfs_iodmax; i++) {
- if (nfs_iodwant[iod])
+ if (nfs_iodwant[iod] == NFSIOD_AVAILABLE)
wakeup(&nfs_iodwant[iod]);
iod--;
}
@@ -159,37 +162,55 @@ out:
SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (nfs_iodmax), sysctl_iodmax, "IU", "");
-int
-nfs_nfsiodnew(void)
+static int
+nfs_nfsiodnew_sync(void)
{
int error, i;
- int newiod;
- if (nfs_numasync >= nfs_iodmax)
- return (-1);
- newiod = -1;
- for (i = 0; i < nfs_iodmax; i++)
+ mtx_assert(&nfs_iod_mtx, MA_OWNED);
+ for (i = 0; i < nfs_iodmax; i++) {
if (nfs_asyncdaemon[i] == 0) {
- nfs_asyncdaemon[i]++;
- newiod = i;
+ nfs_asyncdaemon[i] = 1;
break;
}
- if (newiod == -1)
- return (-1);
+ }
+ if (i == nfs_iodmax)
+ return (0);
mtx_unlock(&nfs_iod_mtx);
- error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
- 0, "nfsiod %d", newiod);
+ error = kthread_create(nfssvc_iod, nfs_asyncdaemon + i, NULL,
+ RFHIGHPID, 0, "nfsiod %d", i);
+ mtx_lock(&nfs_iod_mtx);
+ if (error == 0) {
+ nfs_numasync++;
+ nfs_iodwant[i] = NFSIOD_AVAILABLE;
+ } else
+ nfs_asyncdaemon[i] = 0;
+ return (error);
+}
+
+void
+nfs_nfsiodnew_tq(__unused void *arg, int pending)
+{
+
mtx_lock(&nfs_iod_mtx);
- if (error)
- return (-1);
- nfs_numasync++;
- return (newiod);
+ while (pending > 0) {
+ pending--;
+ nfs_nfsiodnew_sync();
+ }
+ mtx_unlock(&nfs_iod_mtx);
+}
+
+void
+nfs_nfsiodnew(void)
+{
+
+ mtx_assert(&nfs_iod_mtx, MA_OWNED);
+ taskqueue_enqueue(taskqueue_thread, &nfs_nfsiodnew_task);
}
static void
nfsiod_setup(void *dummy)
{
- int i;
int error;
TUNABLE_INT_FETCH("vfs.nfs.iodmin", &nfs_iodmin);
@@ -198,8 +219,8 @@ nfsiod_setup(void *dummy)
if (nfs_iodmin > NFS_MAXASYNCDAEMON)
nfs_iodmin = NFS_MAXASYNCDAEMON;
- for (i = 0; i < nfs_iodmin; i++) {
- error = nfs_nfsiodnew();
+ while (nfs_numasync < nfs_iodmin) {
+ error = nfs_nfsiodnew_sync();
if (error == -1)
panic("nfsiod_setup: nfs_nfsiodnew failed");
}
@@ -235,7 +256,8 @@ nfssvc_iod(void *instance)
goto finish;
if (nmp)
nmp->nm_bufqiods--;
- nfs_iodwant[myiod] = curthread->td_proc;
+ if (nfs_iodwant[myiod] == NFSIOD_NOT_AVAILABLE)
+ nfs_iodwant[myiod] = NFSIOD_AVAILABLE;
nfs_iodmount[myiod] = NULL;
/*
* Always keep at least nfs_iodmin kthreads.
@@ -302,7 +324,7 @@ finish:
nfs_asyncdaemon[myiod] = 0;
if (nmp)
nmp->nm_bufqiods--;
- nfs_iodwant[myiod] = NULL;
+ nfs_iodwant[myiod] = NFSIOD_NOT_AVAILABLE;
nfs_iodmount[myiod] = NULL;
/* Someone may be waiting for the last nfsiod to terminate. */
if (--nfs_numasync == 0)
Modified: stable/7/sys/nfsclient/nfs_subs.c
==============================================================================
--- stable/7/sys/nfsclient/nfs_subs.c Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfs_subs.c Mon Nov 8 15:22:20 2010
(r214986)
@@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$");
#include <sys/sysent.h>
#include <sys/syscall.h>
#include <sys/sysproto.h>
+#include <sys/taskqueue.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
@@ -103,6 +104,7 @@ struct nfs_reqq nfs_reqq;
struct mtx nfs_reqq_mtx;
struct nfs_bufq nfs_bufq;
static struct mtx nfs_xid_mtx;
+struct task nfs_nfsiodnew_task;
/*
* and the reverse mapping from generic to Version 2 procedure numbers
@@ -422,7 +424,7 @@ nfs_init(struct vfsconf *vfsp)
nfs_ticks = 1;
/* Ensure async daemons disabled */
for (i = 0; i < NFS_MAXASYNCDAEMON; i++) {
- nfs_iodwant[i] = NULL;
+ nfs_iodwant[i] = NFSIOD_NOT_AVAILABLE;
nfs_iodmount[i] = NULL;
}
nfs_nhinit(); /* Init the nfsnode table */
@@ -435,6 +437,7 @@ nfs_init(struct vfsconf *vfsp)
mtx_init(&nfs_reqq_mtx, "NFS reqq lock", NULL, MTX_DEF);
mtx_init(&nfs_iod_mtx, "NFS iod lock", NULL, MTX_DEF);
mtx_init(&nfs_xid_mtx, "NFS xid lock", NULL, MTX_DEF);
+ TASK_INIT(&nfs_nfsiodnew_task, 0, nfs_nfsiodnew_tq, NULL);
nfs_pbuf_freecnt = nswbuf / 2 + 1;
@@ -454,11 +457,15 @@ nfs_uninit(struct vfsconf *vfsp)
/*
* Tell all nfsiod processes to exit. Clear nfs_iodmax, and wakeup
* any sleeping nfsiods so they check nfs_iodmax and exit.
+ * Drain nfsiodnew task before we wait for them to finish.
*/
mtx_lock(&nfs_iod_mtx);
nfs_iodmax = 0;
+ mtx_unlock(&nfs_iod_mtx);
+ taskqueue_drain(taskqueue_thread, &nfs_nfsiodnew_task);
+ mtx_lock(&nfs_iod_mtx);
for (i = 0; i < nfs_numasync; i++)
- if (nfs_iodwant[i])
+ if (nfs_iodwant[i] == NFSIOD_AVAILABLE)
wakeup(&nfs_iodwant[i]);
/* The last nfsiod to exit will wake us up when nfs_numasync hits 0 */
while (nfs_numasync)
Modified: stable/7/sys/nfsclient/nfs_vnops.c
==============================================================================
--- stable/7/sys/nfsclient/nfs_vnops.c Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfs_vnops.c Mon Nov 8 15:22:20 2010
(r214986)
@@ -195,7 +195,7 @@ static int nfs_renameit(struct vnode *sd
* Global variables
*/
struct mtx nfs_iod_mtx;
-struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON];
+enum nfsiod_state nfs_iodwant[NFS_MAXASYNCDAEMON];
struct nfsmount *nfs_iodmount[NFS_MAXASYNCDAEMON];
int nfs_numasync = 0;
vop_advlock_t *nfs_advlock_p = nfs_dolock;
Modified: stable/7/sys/nfsclient/nfsnode.h
==============================================================================
--- stable/7/sys/nfsclient/nfsnode.h Mon Nov 8 15:14:14 2010
(r214985)
+++ stable/7/sys/nfsclient/nfsnode.h Mon Nov 8 15:22:20 2010
(r214986)
@@ -173,10 +173,20 @@ struct nfsnode {
#define NFS_TIMESPEC_COMPARE(T1, T2) (((T1)->tv_sec != (T2)->tv_sec) ||
((T1)->tv_nsec != (T2)->tv_nsec))
/*
+ * NFS iod threads can be in one of these two states once spawned.
+ * NFSIOD_NOT_AVAILABLE - Cannot be assigned an I/O operation at this time.
+ * NFSIOD_AVAILABLE - Available to be assigned an I/O operation.
+ */
+enum nfsiod_state {
+ NFSIOD_NOT_AVAILABLE = 0,
+ NFSIOD_AVAILABLE = 1,
+};
+
+/*
* Queue head for nfsiod's
*/
extern TAILQ_HEAD(nfs_bufq, buf) nfs_bufq;
-extern struct proc *nfs_iodwant[NFS_MAXASYNCDAEMON];
+extern enum nfsiod_state nfs_iodwant[NFS_MAXASYNCDAEMON];
extern struct nfsmount *nfs_iodmount[NFS_MAXASYNCDAEMON];
#if defined(_KERNEL)
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