On Thu, 2021-06-03 at 18:59 -0400, Olga Kornievskaia wrote:
> From: Olga Kornievskaia <kolga@xxxxxxxxxx>
>
> Using sysfs's xprt_state attribute, mark a particular transport
> offline.
> It will not be picked during the round-robin selection. It's not
> allowed
> to take the main (1st created transport associated with the
> rpc_client)
> offline.
>
> Signed-off-by: Olga Kornievskaia <kolga@xxxxxxxxxx>
> ---
> include/linux/sunrpc/xprt.h | 2 ++
> net/sunrpc/clnt.c | 1 +
> net/sunrpc/sysfs.c | 42 +++++++++++++++++++++++++++++++++--
> --
> net/sunrpc/xprtmultipath.c | 3 ++-
> 4 files changed, 43 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/sunrpc/xprt.h
> b/include/linux/sunrpc/xprt.h
> index 13a4eaf385cf..72a858f032c7 100644
> --- a/include/linux/sunrpc/xprt.h
> +++ b/include/linux/sunrpc/xprt.h
> @@ -293,6 +293,7 @@ struct rpc_xprt {
> struct rcu_head rcu;
> const struct xprt_class *xprt_class;
> struct rpc_sysfs_xprt *xprt_sysfs;
> + bool main; /* marked if it's the 1st
> transport */
> };
>
> #if defined(CONFIG_SUNRPC_BACKCHANNEL)
> @@ -426,6 +427,7 @@
> void xprt_release_write(struct rpc_xprt *,
> struct rpc_task *);
> #define XPRT_BOUND (4)
> #define XPRT_BINDING (5)
> #define XPRT_CLOSING (6)
> +#define XPRT_OFFLINE (7)
> #define XPRT_CONGESTED (9)
> #define XPRT_CWND_WAIT (10)
> #define XPRT_WRITE_SPACE (11)
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 9bf820bad84c..408618765aa5 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -412,6 +412,7 @@ static struct rpc_clnt * rpc_new_client(const
> struct rpc_create_args *args,
> }
>
> rpc_clnt_set_transport(clnt, xprt, timeout);
> + xprt->main = true;
> xprt_iter_init(&clnt->cl_xpi, xps);
> xprt_switch_put(xps);
>
> diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c
> index ec06c9257c07..02c918c5061b 100644
> --- a/net/sunrpc/sysfs.c
> +++ b/net/sunrpc/sysfs.c
> @@ -118,7 +118,7 @@ static ssize_t rpc_sysfs_xprt_state_show(struct
> kobject *kobj,
> struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj);
> ssize_t ret;
> int locked, connected, connecting, close_wait, bound,
> binding,
> - closing, congested, cwnd_wait, write_space;
> + closing, congested, cwnd_wait, write_space, offline;
>
> if (!xprt)
> return 0;
> @@ -136,8 +136,9 @@ static ssize_t rpc_sysfs_xprt_state_show(struct
> kobject *kobj,
> congested = test_bit(XPRT_CONGESTED, &xprt->state);
> cwnd_wait = test_bit(XPRT_CWND_WAIT, &xprt->state);
> write_space = test_bit(XPRT_WRITE_SPACE, &xprt-
> >state);
> + offline = test_bit(XPRT_OFFLINE, &xprt->state);
>
> - ret = sprintf(buf, "state=%s %s %s %s %s %s %s %s %s
> %s\n",
> + ret = sprintf(buf, "state=%s %s %s %s %s %s %s %s %s
> %s %s\n",
> locked ? "LOCKED" : "",
> connected ? "CONNECTED" : "",
> connecting ? "CONNECTING" : "",
> @@ -147,7 +148,8 @@ static ssize_t rpc_sysfs_xprt_state_show(struct
> kobject *kobj,
> closing ? "CLOSING" : "",
> congested ? "CONGESTED" : "",
> cwnd_wait ? "CWND_WAIT" : "",
> - write_space ? "WRITE_SPACE" : "");
> + write_space ? "WRITE_SPACE" : "",
> + offline ? "OFFLINE" : "");
> }
>
> xprt_put(xprt);
> @@ -223,6 +225,38 @@ static ssize_t
> rpc_sysfs_xprt_dstaddr_store(struct kobject *kobj,
> goto out;
> }
>
> +static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
> + struct kobj_attribute
> *attr,
> + const char *buf, size_t
> count)
> +{
> + struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj);
> + int offline = 0;
> +
> + if (!xprt)
> + return 0;
> +
> + if (!strncmp(buf, "offline", 7))
> + offline = 1;
> + else
> + return -EINVAL;
> +
> + if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED,
> TASK_KILLABLE)) {
> + count = -EINTR;
> + goto out_put;
> + }
> + if (offline) {
> + if (xprt->main)
> + count = -EINVAL;
> + else
> + set_bit(XPRT_OFFLINE, &xprt->state);
> + }
Is there any way to put the transport back online? What say the problem
with the downed IP address gets fixed?
> +
> + xprt_release_write(xprt, NULL);
> +out_put:
> + xprt_put(xprt);
> + return count;
> +}
> +
> int rpc_sysfs_init(void)
> {
> rpc_sunrpc_kset = kset_create_and_add("sunrpc", NULL,
> kernel_kobj);
> @@ -293,7 +327,7 @@ static struct kobj_attribute rpc_sysfs_xprt_info
> = __ATTR(xprt_info,
> 0444, rpc_sysfs_xprt_info_show, NULL);
>
> static struct kobj_attribute rpc_sysfs_xprt_change_state =
> __ATTR(xprt_state,
> - 0644, rpc_sysfs_xprt_state_show, NULL);
> + 0644, rpc_sysfs_xprt_state_show,
> rpc_sysfs_xprt_state_change);
>
> static struct attribute *rpc_sysfs_xprt_attrs[] = {
> &rpc_sysfs_xprt_dstaddr.attr,
> diff --git a/net/sunrpc/xprtmultipath.c b/net/sunrpc/xprtmultipath.c
> index 07e76ae1028a..39551b794b80 100644
> --- a/net/sunrpc/xprtmultipath.c
> +++ b/net/sunrpc/xprtmultipath.c
> @@ -230,7 +230,8 @@ void xprt_iter_default_rewind(struct
> rpc_xprt_iter *xpi)
> static
> bool xprt_is_active(const struct rpc_xprt *xprt)
> {
> - return kref_read(&xprt->kref) != 0;
> + return (kref_read(&xprt->kref) != 0 &&
> + !test_bit(XPRT_OFFLINE, &xprt->state));
> }
>
> static
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@xxxxxxxxxxxxxxx
