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sunrpc: remove an offlined xprt using sysfs
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Once a transport has been put offline, this transport can be also
removed from the list of transports. Any tasks that have been stuck
on this transport would find the next available active transport
and be re-tried. This transport would be removed from the xprt_switch
list and freed.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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Olga Kornievskaia authored and Trond Myklebust committed Jul 8, 2021
1 parent 6a28405 commit 6f08169
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Showing 3 changed files with 47 additions and 4 deletions.
1 change: 1 addition & 0 deletions include/linux/sunrpc/xprt.h
Original file line number Diff line number Diff line change
Expand Up @@ -428,6 +428,7 @@ void xprt_release_write(struct rpc_xprt *, struct rpc_task *);
#define XPRT_BINDING (5)
#define XPRT_CLOSING (6)
#define XPRT_OFFLINE (7)
#define XPRT_REMOVE (8)
#define XPRT_CONGESTED (9)
#define XPRT_CWND_WAIT (10)
#define XPRT_WRITE_SPACE (11)
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24 changes: 24 additions & 0 deletions net/sunrpc/clnt.c
Original file line number Diff line number Diff line change
Expand Up @@ -2106,6 +2106,30 @@ call_connect_status(struct rpc_task *task)
case -ENOTCONN:
case -EAGAIN:
case -ETIMEDOUT:
if (!(task->tk_flags & RPC_TASK_NO_ROUND_ROBIN) &&
(task->tk_flags & RPC_TASK_MOVEABLE) &&
test_bit(XPRT_REMOVE, &xprt->state)) {
struct rpc_xprt *saved = task->tk_xprt;
struct rpc_xprt_switch *xps;

rcu_read_lock();
xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
rcu_read_unlock();
if (xps->xps_nxprts > 1) {
long value;

xprt_release(task);
value = atomic_long_dec_return(&xprt->queuelen);
if (value == 0)
rpc_xprt_switch_remove_xprt(xps, saved);
xprt_put(saved);
task->tk_xprt = NULL;
task->tk_action = call_start;
}
xprt_switch_put(xps);
if (!task->tk_xprt)
return;
}
goto out_retry;
case -ENOBUFS:
rpc_delay(task, HZ >> 2);
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26 changes: 22 additions & 4 deletions net/sunrpc/sysfs.c
Original file line number Diff line number Diff line change
Expand Up @@ -133,7 +133,7 @@ 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, offline;
closing, congested, cwnd_wait, write_space, offline, remove;

if (!xprt)
return 0;
Expand All @@ -152,8 +152,9 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj,
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);
remove = test_bit(XPRT_REMOVE, &xprt->state);

ret = sprintf(buf, "state=%s %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 %s\n",
locked ? "LOCKED" : "",
connected ? "CONNECTED" : "",
connecting ? "CONNECTING" : "",
Expand All @@ -164,7 +165,8 @@ static ssize_t rpc_sysfs_xprt_state_show(struct kobject *kobj,
congested ? "CONGESTED" : "",
cwnd_wait ? "CWND_WAIT" : "",
write_space ? "WRITE_SPACE" : "",
offline ? "OFFLINE" : "");
offline ? "OFFLINE" : "",
remove ? "REMOVE" : "");
}

xprt_put(xprt);
Expand Down Expand Up @@ -251,7 +253,7 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
const char *buf, size_t count)
{
struct rpc_xprt *xprt = rpc_sysfs_xprt_kobj_get_xprt(kobj);
int offline = 0, online = 0;
int offline = 0, online = 0, remove = 0;
struct rpc_xprt_switch *xps = rpc_sysfs_xprt_kobj_get_xprt_switch(kobj);

if (!xprt)
Expand All @@ -261,6 +263,8 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
offline = 1;
else if (!strncmp(buf, "online", 6))
online = 1;
else if (!strncmp(buf, "remove", 6))
remove = 1;
else
return -EINVAL;

Expand All @@ -282,6 +286,20 @@ static ssize_t rpc_sysfs_xprt_state_change(struct kobject *kobj,
spin_lock(&xps->xps_lock);
xps->xps_nactive++;
spin_unlock(&xps->xps_lock);
} else if (remove) {
if (test_bit(XPRT_OFFLINE, &xprt->state)) {
set_bit(XPRT_REMOVE, &xprt->state);
xprt_force_disconnect(xprt);
if (test_bit(XPRT_CONNECTED, &xprt->state)) {
if (!xprt->sending.qlen &&
!xprt->pending.qlen &&
!xprt->backlog.qlen &&
!atomic_long_read(&xprt->queuelen))
rpc_xprt_switch_remove_xprt(xps, xprt);
}
} else {
count = -EINVAL;
}
}

release_tasks:
Expand Down

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