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Fix two cases in the new NFS server where a tsleep() is

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used, when the code should actually protect the tested
variable with a mutex. Since the tsleep()s had a 10sec
timeout, the race would have only delayed the allocation
of a new clientid for a client. The sleeps will also
rarely occur, since having a callback in progress when
a client acquires a new clientid, is unlikely.
in practice, since having a callback in progress when
a fresh clientid is being acquired by a client is unlikely.

MFC after:	1 month
This commit is contained in:
rmacklem 2012-05-12 22:20:55 +00:00
parent 2325662608
commit 4ff8331c1b
1 changed files with 9 additions and 6 deletions
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15
sys/fs/nfsserver/nfs_nfsdstate.c
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@ -331,11 +331,13 @@ nfsrv_setclient(struct nfsrv_descript *nd, struct nfsclient **new_clpp,
* Must wait until any outstanding callback on the old clp
* completes.
*/
NFSLOCKSTATE();
while (clp->lc_cbref) {
clp->lc_flags |= LCL_WAKEUPWANTED;
(void) tsleep((caddr_t)clp, PZERO - 1,
(void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1,
"nfsd clp", 10 * hz);
}
NFSUNLOCKSTATE();
nfsrv_zapclient(clp, p);
*new_clpp = NULL;
goto out;
@ -385,10 +387,13 @@ nfsrv_setclient(struct nfsrv_descript *nd, struct nfsclient **new_clpp,
* Must wait until any outstanding callback on the old clp
* completes.
*/
NFSLOCKSTATE();
while (clp->lc_cbref) {
clp->lc_flags |= LCL_WAKEUPWANTED;
(void) tsleep((caddr_t)clp, PZERO - 1, "nfsd clp", 10 * hz);
(void)mtx_sleep(clp, NFSSTATEMUTEXPTR, PZERO - 1, "nfsd clp",
10 * hz);
}
NFSUNLOCKSTATE();
nfsrv_zapclient(clp, p);
*new_clpp = NULL;
@ -3816,11 +3821,9 @@ nfsrv_docallback(struct nfsclient *clp, int procnum,
clp->lc_cbref--;
if ((clp->lc_flags & LCL_WAKEUPWANTED) && clp->lc_cbref == 0) {
clp->lc_flags &= ~LCL_WAKEUPWANTED;
NFSUNLOCKSTATE();
wakeup((caddr_t)clp);
} else {
NFSUNLOCKSTATE();
wakeup(clp);
}
NFSUNLOCKSTATE();
NFSEXITCODE(error);
return (error);