On Thu, 4 Sep 2014 15:59:14 -0400
"J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> On Tue, Aug 19, 2014 at 02:38:29PM -0400, Jeff Layton wrote:
> > In order to support lifting the grace period early, we must tell
> > nfsdcltrack what sort of client the "create" upcall is for. We can't
> > reliably tell if a v4.0 client has completed reclaiming, so we can only
> > lift the grace period once all the v4.1+ clients have issued a
> > RECLAIM_COMPLETE and if there are no v4.0 clients.
>
> We really only care about 4.0 vs 4.1 clients. Maybe
> NFSDCLTRACK_CLIENT_WILL_RECLAIM_COMPLETE=Y|N would be better.
>
> --b.
>
We have v4.2 in the queue now, and v4.3 will eventually come later.
Maybe v4.4 or v4.5 will change how recovery works? I figured it was
better to pass down more specific info and let userland sort out
what to do with it.
That said, if you think that a simple y/n flag is better, then I'll go
with that.
> >
> > Also, in order to lift the grace period, we have to tell userland when
> > the grace period started so that it can tell whether a RECLAIM_COMPLETE
> > has been issued for each client since then.
> >
> > Since this is all optional info, we pass it along in environment
> > variables to the "init" and "create" upcalls. By doing this, we don't
> > need to revise the upcall format. The UMH upcall can simply make use of
> > this info if it happens to be present. If it's not then it can just
> > avoid lifting the grace period early.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
> > ---
> > fs/nfsd/nfs4recover.c | 90 ++++++++++++++++++++++++++++++++++++++++++++-------
> > fs/nfsd/nfs4state.c | 4 +--
> > 2 files changed, 80 insertions(+), 14 deletions(-)
> >
> > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
> > index a0d2ba956a3f..2b61bcd92b58 100644
> > --- a/fs/nfsd/nfs4recover.c
> > +++ b/fs/nfsd/nfs4recover.c
> > @@ -1062,6 +1062,8 @@ MODULE_PARM_DESC(cltrack_legacy_disable,
> >
> > #define LEGACY_TOPDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_TOPDIR="
> > #define LEGACY_RECDIR_ENV_PREFIX "NFSDCLTRACK_LEGACY_RECDIR="
> > +#define CLIENT_MINORVERS_ENV_PREFIX "NFSDCLTRACK_CLIENT_MINORVERSION="
> > +#define GRACE_START_ENV_PREFIX "NFSDCLTRACK_GRACE_START="
> >
> > static char *
> > nfsd4_cltrack_legacy_topdir(void)
> > @@ -1126,10 +1128,60 @@ nfsd4_cltrack_legacy_recdir(const struct xdr_netobj *name)
> > return result;
> > }
> >
> > +static char *
> > +nfsd4_cltrack_client_minorversion(struct nfs4_client *clp)
> > +{
> > + int copied;
> > + size_t len;
> > + char *result;
> > +
> > + /* prefix + max width of integer string + terminating NULL */
> > + len = strlen(CLIENT_MINORVERS_ENV_PREFIX) + 10 + 1;
> > +
> > + result = kmalloc(len, GFP_KERNEL);
> > + if (!result)
> > + return result;
> > +
> > + copied = snprintf(result, len, CLIENT_MINORVERS_ENV_PREFIX "%u",
> > + clp->cl_minorversion);
> > + if (copied >= len) {
> > + /* just return nothing if output was truncated */
> > + kfree(result);
> > + return NULL;
> > + }
> > +
> > + return result;
> > +}
> > +
> > +static char *
> > +nfsd4_cltrack_grace_start(time_t grace_start)
> > +{
> > + int copied;
> > + size_t len;
> > + char *result;
> > +
> > + /* prefix + max width of int64_t string + terminating NULL */
> > + len = strlen(GRACE_START_ENV_PREFIX) + 22 + 1;
> > +
> > + result = kmalloc(len, GFP_KERNEL);
> > + if (!result)
> > + return result;
> > +
> > + copied = snprintf(result, len, GRACE_START_ENV_PREFIX "%ld",
> > + grace_start);
> > + if (copied >= len) {
> > + /* just return nothing if output was truncated */
> > + kfree(result);
> > + return NULL;
> > + }
> > +
> > + return result;
> > +}
> > +
> > static int
> > -nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
> > +nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *env0, char *env1)
> > {
> > - char *envp[2];
> > + char *envp[3];
> > char *argv[4];
> > int ret;
> >
> > @@ -1140,10 +1192,12 @@ nfsd4_umh_cltrack_upcall(char *cmd, char *arg, char *legacy)
> >
> > dprintk("%s: cmd: %s\n", __func__, cmd);
> > dprintk("%s: arg: %s\n", __func__, arg ? arg : "(null)");
> > - dprintk("%s: legacy: %s\n", __func__, legacy ? legacy : "(null)");
> > + dprintk("%s: env0: %s\n", __func__, env0 ? env0 : "(null)");
> > + dprintk("%s: env1: %s\n", __func__, env1 ? env1 : "(null)");
> >
> > - envp[0] = legacy;
> > - envp[1] = NULL;
> > + envp[0] = env0;
> > + envp[1] = env1;
> > + envp[2] = NULL;
> >
> > argv[0] = (char *)cltrack_prog;
> > argv[1] = cmd;
> > @@ -1187,28 +1241,40 @@ bin_to_hex_dup(const unsigned char *src, int srclen)
> > }
> >
> > static int
> > -nfsd4_umh_cltrack_init(struct net __attribute__((unused)) *net)
> > +nfsd4_umh_cltrack_init(struct net *net)
> > {
> > + int ret;
> > + struct nfsd_net *nn = net_generic(net, nfsd_net_id);
> > + char *grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
> > +
> > /* XXX: The usermode helper s not working in container yet. */
> > if (net != &init_net) {
> > WARN(1, KERN_ERR "NFSD: attempt to initialize umh client "
> > "tracking in a container!\n");
> > return -EINVAL;
> > }
> > - return nfsd4_umh_cltrack_upcall("init", NULL, NULL);
> > +
> > + ret = nfsd4_umh_cltrack_upcall("init", NULL, grace_start, NULL);
> > + kfree(grace_start);
> > + return ret;
> > }
> >
> > static void
> > nfsd4_umh_cltrack_create(struct nfs4_client *clp)
> > {
> > - char *hexid;
> > + char *hexid, *minorvers, *grace_start;
> > + struct nfsd_net *nn = net_generic(clp->net, nfsd_net_id);
> >
> > hexid = bin_to_hex_dup(clp->cl_name.data, clp->cl_name.len);
> > if (!hexid) {
> > dprintk("%s: can't allocate memory for upcall!\n", __func__);
> > return;
> > }
> > - nfsd4_umh_cltrack_upcall("create", hexid, NULL);
> > + minorvers = nfsd4_cltrack_client_minorversion(clp);
> > + grace_start = nfsd4_cltrack_grace_start(nn->boot_time);
> > + nfsd4_umh_cltrack_upcall("create", hexid, minorvers, grace_start);
> > + kfree(minorvers);
> > + kfree(grace_start);
> > kfree(hexid);
> > }
> >
> > @@ -1222,7 +1288,7 @@ nfsd4_umh_cltrack_remove(struct nfs4_client *clp)
> > dprintk("%s: can't allocate memory for upcall!\n", __func__);
> > return;
> > }
> > - nfsd4_umh_cltrack_upcall("remove", hexid, NULL);
> > + nfsd4_umh_cltrack_upcall("remove", hexid, NULL, NULL);
> > kfree(hexid);
> > }
> >
> > @@ -1238,7 +1304,7 @@ nfsd4_umh_cltrack_check(struct nfs4_client *clp)
> > return -ENOMEM;
> > }
> > legacy = nfsd4_cltrack_legacy_recdir(&clp->cl_name);
> > - ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy);
> > + ret = nfsd4_umh_cltrack_upcall("check", hexid, legacy, NULL);
> > kfree(legacy);
> > kfree(hexid);
> > return ret;
> > @@ -1252,7 +1318,7 @@ nfsd4_umh_cltrack_grace_done(struct nfsd_net *nn)
> >
> > sprintf(timestr, "%ld", nn->boot_time);
> > legacy = nfsd4_cltrack_legacy_topdir();
> > - nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy);
> > + nfsd4_umh_cltrack_upcall("gracedone", timestr, legacy, NULL);
> > kfree(legacy);
> > }
> >
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 21becb29dae1..5b04353bf2ec 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -6342,10 +6342,10 @@ nfs4_state_start_net(struct net *net)
> > ret = nfs4_state_create_net(net);
> > if (ret)
> > return ret;
> > - nfsd4_client_tracking_init(net);
> > nn->boot_time = get_seconds();
> > - locks_start_grace(net, &nn->nfsd4_manager);
> > nn->grace_ended = false;
> > + locks_start_grace(net, &nn->nfsd4_manager);
> > + nfsd4_client_tracking_init(net);
> > printk(KERN_INFO "NFSD: starting %ld-second grace period (net %p)\n",
> > nn->nfsd4_grace, net);
> > queue_delayed_work(laundry_wq, &nn->laundromat_work, nn->nfsd4_grace * HZ);
> > --
> > 1.9.3
> >
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
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