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Add a timeout for the negative name cache entries in the NFS client.

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This avoids a bogus negative name cache entry from persisting forever
when another client creates an entry with the same name within the
same NFS server time of day clock tick. The mount option negnametimeo
can be used to override the default timeout interval on a
per-mount-point basis. Setting negnametimeo to 0 disables negative
name caching for the mount point.
I also fixed one obvious typo where args.timeo should be
args.maxgrouplist.

Submitted by:	jhb (earlier version)
Reviewed by:	jhb
MFC after:	2 weeks
This commit is contained in:
Rick Macklem 2010-01-21 20:57:25 +00:00
parent 097d042584
commit f957b30da2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=202767
4 changed files with 33 additions and 8 deletions
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24
sys/nfsclient/nfs_vfsops.c
View File

@ -114,7 +114,7 @@ static void nfs_decode_args(struct mount *mp, struct nfsmount *nmp,
struct nfs_args *argp, const char *hostname);
static int mountnfs(struct nfs_args *, struct mount *,
struct sockaddr *, char *, struct vnode **,
struct ucred *cred);
struct ucred *cred, int);
static vfs_mount_t nfs_mount;
static vfs_cmount_t nfs_cmount;
static vfs_unmount_t nfs_unmount;
@ -551,7 +551,7 @@ nfs_mountdiskless(char *path,
nam = sodupsockaddr((struct sockaddr *)sin, M_WAITOK);
if ((error = mountnfs(args, mp, nam, path, vpp,
td->td_ucred)) != 0) {
td->td_ucred, NFS_DEFAULT_NEGNAMETIMEO)) != 0) {
printf("nfs_mountroot: mount %s on /: %d\n", path, error);
return (error);
}
@ -778,7 +778,7 @@ static const char *nfs_opts[] = { "from", "nfs_args",
"readdirsize", "soft", "hard", "mntudp", "tcp", "udp", "wsize", "rsize",
"retrans", "acregmin", "acregmax", "acdirmin", "acdirmax",
"deadthresh", "hostname", "timeout", "addr", "fh", "nfsv3", "sec",
"maxgroups", "principal",
"maxgroups", "principal", "negnametimeo",
NULL };
/*
@ -827,6 +827,7 @@ nfs_mount(struct mount *mp)
size_t len;
u_char nfh[NFSX_V3FHMAX];
char *opt;
int negnametimeo = NFS_DEFAULT_NEGNAMETIMEO;
has_nfs_args_opt = 0;
has_addr_opt = 0;
@ -1029,7 +1030,7 @@ nfs_mount(struct mount *mp)
}
if (vfs_getopt(mp->mnt_optnew, "maxgroups", (void **)&opt, NULL) == 0) {
ret = sscanf(opt, "%d", &args.maxgrouplist);
if (ret != 1 || args.timeo <= 0) {
if (ret != 1 || args.maxgrouplist <= 0) {
vfs_mount_error(mp, "illegal maxgroups: %s",
opt);
error = EINVAL;
@ -1037,6 +1038,16 @@ nfs_mount(struct mount *mp)
}
args.flags |= NFSMNT_MAXGRPS;
}
if (vfs_getopt(mp->mnt_optnew, "negnametimeo", (void **)&opt, NULL)
== 0) {
ret = sscanf(opt, "%d", &negnametimeo);
if (ret != 1 || negnametimeo < 0) {
vfs_mount_error(mp, "illegal negnametimeo: %s",
opt);
error = EINVAL;
goto out;
}
}
if (vfs_getopt(mp->mnt_optnew, "addr", (void **)&args.addr,
&args.addrlen) == 0) {
has_addr_opt = 1;
@ -1125,7 +1136,7 @@ nfs_mount(struct mount *mp)
}
}
error = mountnfs(&args, mp, nam, args.hostname, &vp,
curthread->td_ucred);
curthread->td_ucred, negnametimeo);
out:
if (!error) {
MNT_ILOCK(mp);
@ -1167,7 +1178,7 @@ nfs_cmount(struct mntarg *ma, void *data, int flags)
*/
static int
mountnfs(struct nfs_args *argp, struct mount *mp, struct sockaddr *nam,
char *hst, struct vnode **vpp, struct ucred *cred)
char *hst, struct vnode **vpp, struct ucred *cred, int negnametimeo)
{
struct nfsmount *nmp;
struct nfsnode *np;
@ -1217,6 +1228,7 @@ mountnfs(struct nfs_args *argp, struct mount *mp, struct sockaddr *nam,
nmp->nm_numgrps = NFS_MAXGRPS;
nmp->nm_readahead = NFS_DEFRAHEAD;
nmp->nm_deadthresh = NFS_MAXDEADTHRESH;
nmp->nm_negnametimeo = negnametimeo;
nmp->nm_tprintf_delay = nfs_tprintf_delay;
if (nmp->nm_tprintf_delay < 0)
nmp->nm_tprintf_delay = 0;

11
sys/nfsclient/nfs_vnops.c
View File

@ -982,8 +982,13 @@ nfs_lookup(struct vop_lookup_args *ap)
* modification time of the parent directory matches
* our cached copy. Otherwise, we discard all of the
* negative cache entries for this directory.
* negative cache entries for this directory. We also
* only trust -ve cache entries for less than
* nm_negative_namecache_timeout seconds.
*/
if (VOP_GETATTR(dvp, &vattr, cnp->cn_cred) == 0 &&
if ((u_int)(ticks - np->n_dmtime_ticks) <
(nmp->nm_negnametimeo * hz) &&
VOP_GETATTR(dvp, &vattr, cnp->cn_cred) == 0 &&
vattr.va_mtime.tv_sec == np->n_dmtime) {
nfsstats.lookupcache_hits++;
return (ENOENT);
@ -1157,8 +1162,10 @@ nfs_lookup(struct vop_lookup_args *ap)
*/
mtx_lock(&np->n_mtx);
if (np->n_dmtime <= dmtime) {
if (np->n_dmtime == 0)
if (np->n_dmtime == 0) {
np->n_dmtime = dmtime;
np->n_dmtime_ticks = ticks;
}
mtx_unlock(&np->n_mtx);
cache_enter(dvp, NULL, cnp);
} else

5
sys/nfsclient/nfsmount.h
View File

@ -85,6 +85,7 @@ struct nfsmount {
struct rpc_timers nm_timers[NFS_MAX_TIMER]; /* RTT Timers for rpcs */
char nm_principal[MNAMELEN]; /* GSS-API principal of server */
gss_OID nm_mech_oid; /* OID of selected GSS-API mechanism */
int nm_negnametimeo; /* timeout for -ve entries (sec) */
/* NFSv4 */
uint64_t nm_clientid;
@ -107,6 +108,10 @@ struct nfsmount {
#define NFS_TPRINTF_DELAY 30
#endif
#ifndef NFS_DEFAULT_NEGNAMETIMEO
#define NFS_DEFAULT_NEGNAMETIMEO 60
#endif
#define NFS_PCATCH (PCATCH | PBDRY)
#endif

1
sys/nfsclient/nfsnode.h
View File

@ -114,6 +114,7 @@ struct nfsnode {
struct timespec n_mtime; /* Prev modify time. */
time_t n_ctime; /* Prev create time. */
time_t n_dmtime; /* Prev dir modify time. */
int n_dmtime_ticks; /* Tick of -ve cache entry */
time_t n_expiry; /* Lease expiry time */
nfsfh_t *n_fhp; /* NFS File Handle */
struct vnode *n_vnode; /* associated vnode */