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Do not fork nfsiod directly from the vop methods. This causes LORs between

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vnode lock and several locks needed during fork, like fd lock.

Instead, schedule the task to be executed in the taskqueue context. We
still waiting for the fork to finish, but the context of the thread
executing the task does not make real LORs with our vnode lock.

Submitted by:	pluknet at gmail com
Reviewed by:	jhb
Tested by:	pho
MFC after:	3 weeks
This commit is contained in:
Konstantin Belousov 2010-09-12 19:06:08 +00:00
parent ab7d0151f9
commit 57bfe0a9f8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=212506
3 changed files with 48 additions and 2 deletions
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2
sys/nfsclient/nfs.h
View File

@ -125,6 +125,7 @@ extern struct uma_zone *nfsmount_zone;
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;
@ -253,6 +254,7 @@ 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(int);
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 *);

41
sys/nfsclient/nfs_nfsiod.c
View File

@ -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>
@ -75,6 +76,16 @@ static MALLOC_DEFINE(M_NFSSVC, "nfsclient_srvsock", "Nfs server structure");
static void nfssvc_iod(void *);
struct nfsiod_str {
STAILQ_ENTRY(nfsiod_str) ni_links;
int *ni_inst;
int ni_iod;
int ni_error;
int ni_done;
};
static STAILQ_HEAD(, nfsiod_str) nfsiodhead =
STAILQ_HEAD_INITIALIZER(nfsiodhead);
static int nfs_asyncdaemon[NFS_MAXASYNCDAEMON];
SYSCTL_DECL(_vfs_nfs);
@ -159,11 +170,30 @@ SYSCTL_PROC(_vfs_nfs, OID_AUTO, iodmax, CTLTYPE_UINT | CTLFLAG_RW, 0,
sizeof (nfs_iodmax), sysctl_iodmax, "IU",
"Max number of nfsiod kthreads");
void
nfs_nfsiodnew_tq(__unused void *arg, int pending)
{
struct nfsiod_str *nip;
mtx_lock(&nfs_iod_mtx);
while ((nip = STAILQ_FIRST(&nfsiodhead)) != NULL) {
STAILQ_REMOVE_HEAD(&nfsiodhead, ni_links);
mtx_unlock(&nfs_iod_mtx);
nip->ni_error = kproc_create(nfssvc_iod, nip->ni_inst, NULL,
RFHIGHPID, 0, "nfsiod %d", nip->ni_iod);
nip->ni_done = 1;
mtx_lock(&nfs_iod_mtx);
wakeup(nip);
}
mtx_unlock(&nfs_iod_mtx);
}
int
nfs_nfsiodnew(int set_iodwant)
{
int error, i;
int newiod;
struct nfsiod_str *nip;
if (nfs_numasync >= nfs_iodmax)
return (-1);
@ -179,9 +209,16 @@ nfs_nfsiodnew(int set_iodwant)
if (set_iodwant > 0)
nfs_iodwant[i] = NFSIOD_CREATED_FOR_NFS_ASYNCIO;
mtx_unlock(&nfs_iod_mtx);
error = kproc_create(nfssvc_iod, nfs_asyncdaemon + i, NULL, RFHIGHPID,
0, "nfsiod %d", newiod);
nip = malloc(sizeof(*nip), M_TEMP, M_WAITOK | M_ZERO);
nip->ni_inst = nfs_asyncdaemon + i;
nip->ni_iod = newiod;
mtx_lock(&nfs_iod_mtx);
STAILQ_INSERT_TAIL(&nfsiodhead, nip, ni_links);
taskqueue_enqueue(taskqueue_thread, &nfs_nfsiodnew_task);
while (!nip->ni_done)
mtx_sleep(nip, &nfs_iod_mtx, 0, "niwt", 0);
error = nip->ni_error;
free(nip, M_TEMP);
if (error) {
if (set_iodwant > 0)
nfs_iodwant[i] = NFSIOD_NOT_AVAILABLE;

7
sys/nfsclient/nfs_subs.c
View File

@ -59,6 +59,7 @@ __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>
@ -117,6 +118,7 @@ int nfs_pbuf_freecnt = -1; /* start out unlimited */
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
@ -354,6 +356,7 @@ nfs_init(struct vfsconf *vfsp)
*/
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;
@ -368,9 +371,13 @@ 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] == NFSIOD_AVAILABLE)
wakeup(&nfs_iodwant[i]);