summaryrefslogtreecommitdiffstats
path: root/xlators/cluster/nsr-client/src/fop-template.c
blob: 699b07d407073202001c518aa03df6921afe2b31 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
// template-name fop
$TYPE$
nsrc_$NAME$ (call_frame_t *frame, xlator_t *this,
             $ARGS_LONG$)
{
        nsrc_local_t    *local          = NULL;
        xlator_t        *target_xl      = ACTIVE_CHILD(this);

        local = mem_get(this->local_pool);
        if (!local) {
                goto err;
        }

        local->stub = fop_$NAME$_stub (frame, nsrc_$NAME$_continue,
                                       $ARGS_SHORT$);
        if (!local->stub) {
                goto err;
        }
        local->curr_xl = target_xl;
        local->scars = 0;

        frame->local = local;
        STACK_WIND_COOKIE (frame, nsrc_$NAME$_cbk, target_xl,
                    target_xl, target_xl->fops->$NAME$,
                    $ARGS_SHORT$);
        return 0;

err:
        if (local) {
                mem_put(local);
        }
        STACK_UNWIND_STRICT ($NAME$, frame, -1, ENOMEM,
                             $DEFAULTS$);
        return 0;
}

// template-name cbk
$TYPE$
nsrc_$NAME$_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
                 int32_t op_ret, int32_t op_errno,
                 $ARGS_LONG$)
{
        nsrc_local_t    *local          = frame->local;
        xlator_t        *last_xl        = cookie;
        xlator_t        *next_xl;
        nsrc_private_t  *priv           = this->private;
        struct timespec spec;

        if (op_ret != (-1)) {
                if (local->scars) {
                        gf_log (this->name, GF_LOG_INFO,
                                HILITE("retried %p OK"), frame->local);
                }
                priv->active = last_xl;
                goto unwind;
        }
        if ((op_errno != EREMOTE) && (op_errno != ENOTCONN)) {
                goto unwind;
        }

        /* TBD: get leader ID from xdata? */
        next_xl = next_xlator(this,last_xl);
        /*
         * We can't just give up after we've tried all bricks, because it's
         * quite likely that a new leader election just hasn't finished yet.
         * We also shouldn't retry endlessly, and especially not at a high
         * rate, but that's good enough while we work on other things.
         * 
         * TBD: implement slow/finite retry via a worker thread
         */
        if (!next_xl || (local->scars >= SCAR_LIMIT)) {
                gf_log (this->name, GF_LOG_DEBUG,
                        HILITE("ran out of retries for %p"), frame->local);
                goto unwind;
        }

        local->curr_xl = next_xl;
        local->scars += 1;
        spec.tv_sec = 1;
        spec.tv_nsec = 0;
        /*
         * WARNING
         *
         * Just calling gf_timer_call_after like this leaves open the
         * possibility that writes will get reordered, if a first write is
         * rescheduled and then a second comes along to find an updated
         * priv->active before the first actually executes.  We might need to
         * implement a stricter (and more complicated) queuing mechanism to
         * ensure absolute consistency in this case.
         */
        if (gf_timer_call_after(this->ctx,spec,nsrc_retry_cb,local)) {
                return 0;
        }

unwind:
        call_stub_destroy(local->stub);
        STACK_UNWIND_STRICT ($NAME$, frame, op_ret, op_errno,
                                     $ARGS_SHORT$);
        return 0;
}

// template-name cont-func
$TYPE$
nsrc_$NAME$_continue (call_frame_t *frame, xlator_t *this,
                      $ARGS_LONG$)
{
        nsrc_local_t    *local  = frame->local;

        STACK_WIND_COOKIE (frame, nsrc_$NAME$_cbk, local->curr_xl,
                           local->curr_xl, local->curr_xl->fops->$NAME$,
                           $ARGS_SHORT$);
        return 0;
}