mars/mars_copy.c

575 lines
14 KiB
C

// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
// Copy brick (just for demonstration)
//#define BRICK_DEBUGGING
//#define MARS_DEBUGGING
//#define IO_DEBUGGING
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kthread.h>
#include "mars.h"
///////////////////////// own type definitions ////////////////////////
#include "mars_copy.h"
///////////////////////// own helper functions ////////////////////////
/* TODO:
* The clash logic is untested / alpha stage (Feb. 2011).
*
* For now, the output is never used, so this cannot do harm.
*
* In order to get the output really working / enterprise grade,
* some larger test effort should be invested.
*/
static inline
void _clash(struct copy_brick *brick)
{
brick->trigger = true;
set_bit(0, &brick->clash);
wake_up_interruptible(&brick->event);
}
static inline
int _clear_clash(struct copy_brick *brick)
{
int old;
old = test_and_clear_bit(0, &brick->clash);
return old;
}
/* Current semantics:
*
* All writes are always going to the original input A. They are _not_
* replicated to B.
*
* In order to get B really uptodate, you have to replay the right
* transaction logs there (at the right time).
* [If you had no writes on A at all during the copy, of course
* this is not necessary]
*
* When optimize_mode is on, reads can utilize the already copied
* region from B, but only as long as this region has not been
* invalidated by writes (indicated by low_dirty).
*
* TODO: implement replicated writes, together with some transaction
* replay logic applying the transaction logs _only_ after
* crashes during inconsistency caused by partial replication of writes.
*/
static
int _determine_input(struct copy_brick *brick, struct mref_object *mref)
{
int rw;
int below;
int behind;
loff_t ref_end;
if (!brick->optimize_mode || brick->low_dirty)
return INPUT_A_IO;
ref_end = mref->ref_pos + mref->ref_len;
below = ref_end <= brick->copy_start;
behind = !brick->copy_end || mref->ref_pos >= brick->copy_end;
rw = mref->ref_may_write | mref->ref_rw;
if (rw) {
if (!behind) {
brick->low_dirty = true;
if (!below) {
_clash(brick);
wake_up_interruptible(&brick->event);
}
}
return INPUT_A_IO;
}
if (below)
return INPUT_B_IO;
return INPUT_A_IO;
}
#define MAKE_INDEX(pos) (((pos) / PAGE_SIZE) % MAX_COPY_PARA)
static
void copy_endio(struct generic_callback *cb)
{
struct copy_mref_aspect *mref_a;
struct mref_object *mref;
struct copy_brick *brick;
int index;
int queue;
mref_a = cb->cb_private;
CHECK_PTR(mref_a, err);
mref = mref_a->object;
CHECK_PTR(mref, err);
brick = mref_a->brick;
CHECK_PTR(brick, err);
queue = mref_a->queue;
index = MAKE_INDEX(mref->ref_pos);
MARS_IO("queue = %d index = %d pos = %lld status = %d\n", queue, index, mref->ref_pos, cb->cb_error);
if (unlikely(queue < 0 || queue >= 2)) {
MARS_ERR("bad queue %d\n", queue);
_clash(brick);
goto exit;
}
if (unlikely(brick->table[index][queue])) {
MARS_ERR("table corruption at %d %d (%p => %p)\n", index, queue, brick->table[index], mref);
_clash(brick);
brick->state[index] = -EINVAL;
goto exit;
}
if (unlikely(cb->cb_error < 0)) {
MARS_ERR("IO error %d on index %d, old state =%d\n", cb->cb_error, index, brick->state[index]);
brick->state[index] = cb->cb_error;
} else if (likely(brick->state[index] > 0)) {
brick->table[index][queue] = mref;
}
exit:
atomic_dec(&brick->copy_flight);
brick->trigger = true;
wake_up_interruptible(&brick->event);
return;
err:
MARS_FAT("cannot handle callback\n");
}
static
int _make_mref(struct copy_brick *brick, int index, int queue, void *data, loff_t pos, int rw)
{
struct mref_object *mref;
struct copy_mref_aspect *mref_a;
struct copy_input *input;
loff_t tmp_pos;
int len;
int status = -1;
tmp_pos = brick->copy_end;
if (brick->clash || !tmp_pos)
goto done;
mref = copy_alloc_mref(brick->outputs[0], &brick->mref_object_layout);
status = -ENOMEM;
if (unlikely(!mref))
goto done;
mref_a = copy_mref_get_aspect(brick->outputs[0], mref);
if (unlikely(!mref_a)) {
kfree(mref);
goto done;
}
mref_a->brick = brick;
mref_a->queue = queue;
mref->ref_may_write = rw;
mref->ref_rw = rw;
mref->ref_data = data;
mref->ref_pos = pos;
len = PAGE_SIZE - (pos & (PAGE_SIZE-1));
if (pos + len > tmp_pos) {
len = tmp_pos - pos;
}
mref->ref_len = len;
mref->_ref_cb.cb_private = mref_a;
mref->_ref_cb.cb_fn = copy_endio;
mref->ref_cb = &mref->_ref_cb;
input = queue ? brick->inputs[INPUT_B_COPY] : brick->inputs[INPUT_A_COPY];
status = GENERIC_INPUT_CALL(input, mref_get, mref);
if (unlikely(status < 0)) {
MARS_ERR("status = %d\n", status);
mars_free_mref(mref);
goto done;
}
MARS_IO("queue = %d index = %d pos = %lld len = %d rw = %d\n", queue, index, mref->ref_pos, mref->ref_len, rw);
atomic_inc(&brick->copy_flight);
GENERIC_INPUT_CALL(input, mref_io, mref);
done:
return status;
}
static
void _clear_mref(struct copy_brick *brick, int index, int queue)
{
struct mref_object *mref = brick->table[index][queue];
if (mref) {
struct copy_input *input;
input = queue ? brick->inputs[INPUT_B_COPY] : brick->inputs[INPUT_A_COPY];
GENERIC_INPUT_CALL(input, mref_put, mref);
brick->table[index][queue] = NULL;
}
}
static
int _next_state(struct copy_brick *brick, loff_t pos)
{
struct mref_object *mref1;
struct mref_object *mref2;
int index = MAKE_INDEX(pos);
char state;
char next_state;
int i;
int status;
state = brick->state[index];
next_state = -1;
mref2 = NULL;
status = 0;
MARS_IO("index = %d state = %d pos = %lld\n", index, state, pos);
switch (state) {
case COPY_STATE_START:
if (brick->table[index][0] || brick->table[index][1]) {
MARS_ERR("index %d not startable\n", index);
status = -EPROTO;
goto done;
}
i = 0;
next_state = COPY_STATE_READ1;
if (brick->verify_mode) {
i = 1;
next_state = COPY_STATE_READ2;
}
for ( ; i >= 0; i--) {
status = _make_mref(brick, index, i, NULL, pos, 0);
if (status < 0) {
break;
}
}
break;
case COPY_STATE_READ2:
mref2 = brick->table[index][1];
if (!mref2) {
goto done;
}
/* fallthrough */
case COPY_STATE_READ1:
mref1 = brick->table[index][0];
if (!mref1) {
goto done;
}
if (mref2) {
int len = mref1->ref_len;
if (len == mref2->ref_len &&
!memcmp(mref1->ref_data, mref2->ref_data, len)) {
/* skip start of writing, goto final treatment of writeout */
next_state = COPY_STATE_WRITE;
brick->state[index] = next_state;
goto COPY_STATE_WRITE;
}
_clear_mref(brick, index, 1);
}
/* start writeout */
next_state = COPY_STATE_WRITE;
status = _make_mref(brick, index, 1, mref1->ref_data, pos, 1);
break;
case COPY_STATE_WRITE:
COPY_STATE_WRITE:
mref2 = brick->table[index][1];
if (!mref2 || brick->copy_start != pos) {
MARS_IO("irrelevant\n");
goto done;
}
if (!brick->clash) {
brick->copy_start += mref2->ref_len;
MARS_IO("new copy_start = %lld\n", brick->copy_start);
if (brick->copy_start > brick->copy_last + 1024 * 1024 * 1024 || brick->copy_start == brick->copy_end) {
brick->copy_last = brick->copy_start;
brick->power.percent_done = brick->copy_end > 0 ? brick->copy_start * 100 / brick->copy_end : 0;
MARS_INF("'%s' copied %lld / %lld bytes (%lld%%)\n", brick->brick_name, brick->copy_last, brick->copy_end, brick->copy_end? brick->copy_last * 100 / brick->copy_end : 100);
}
}
next_state = COPY_STATE_CLEANUP;
/* fallthrough */
case COPY_STATE_CLEANUP:
_clear_mref(brick, index, 0);
_clear_mref(brick, index, 1);
next_state = COPY_STATE_START;
break;
default:
MARS_ERR("illegal state %d at index %d\n", state, index);
_clash(brick);
status = -EILSEQ;
}
brick->state[index] = next_state;
if (status < 0) {
brick->state[index] = -1;
MARS_ERR("status = %d\n", status);
_clash(brick);
}
done:
return status;
}
static
void _run_copy(struct copy_brick *brick)
{
int max;
loff_t pos;
int i;
int status;
if (_clear_clash(brick)) {
MARS_DBG("clash\n");
if (atomic_read(&brick->copy_flight)) {
/* wait until all pending copy IO has finished
*/
_clash(brick);
MARS_DBG("re-clash\n");
msleep(50);
return;
}
for (i = 0; i < MAX_COPY_PARA; i++) {
brick->table[i][0] = NULL;
brick->table[i][1] = NULL;
brick->state[i] = COPY_STATE_START;
}
}
max = MAX_COPY_PARA - atomic_read(&brick->io_flight) * 2;
MARS_IO("max = %d\n", max);
for (pos = brick->copy_start; pos < brick->copy_end; pos = ((pos / PAGE_SIZE) + 1) * PAGE_SIZE) {
//MARS_IO("pos = %lld\n", pos);
if (brick->clash || max-- <= 0)
break;
status = _next_state(brick, pos);
}
}
static int _copy_thread(void *data)
{
struct copy_brick *brick = data;
MARS_DBG("--------------- copy_thread %p starting\n", brick);
mars_power_led_on((void*)brick, true);
brick->trigger = true;
while (!kthread_should_stop()) {
loff_t old_start = brick->copy_start;
loff_t old_end = brick->copy_end;
if (old_end > 0)
_run_copy(brick);
wait_event_interruptible_timeout(brick->event,
brick->trigger || brick->copy_start != old_start || brick->copy_end != old_end || kthread_should_stop(),
20 * HZ);
brick->trigger = false;
}
MARS_DBG("--------------- copy_thread terminating\n");
wait_event_interruptible_timeout(brick->event, !atomic_read(&brick->copy_flight), 300 * HZ);
mars_power_led_off((void*)brick, true);
MARS_DBG("--------------- copy_thread done.\n");
return 0;
}
////////////////// own brick / input / output operations //////////////////
static int copy_get_info(struct copy_output *output, struct mars_info *info)
{
struct copy_input *input = output->brick->inputs[INPUT_B_IO];
return GENERIC_INPUT_CALL(input, mars_get_info, info);
}
static int copy_ref_get(struct copy_output *output, struct mref_object *mref)
{
struct copy_input *input;
int index;
int status;
index = _determine_input(output->brick, mref);
input = output->brick->inputs[index];
status = GENERIC_INPUT_CALL(input, mref_get, mref);
if (status >= 0) {
atomic_inc(&output->brick->io_flight);
}
return status;
}
static void copy_ref_put(struct copy_output *output, struct mref_object *mref)
{
struct copy_input *input;
int index;
index = _determine_input(output->brick, mref);
input = output->brick->inputs[index];
GENERIC_INPUT_CALL(input, mref_put, mref);
if (atomic_dec_and_test(&output->brick->io_flight)) {
output->brick->trigger = true;
wake_up_interruptible(&output->brick->event);
}
}
static void copy_ref_io(struct copy_output *output, struct mref_object *mref)
{
struct copy_input *input;
int index;
index = _determine_input(output->brick, mref);
input = output->brick->inputs[index];
GENERIC_INPUT_CALL(input, mref_io, mref);
}
static int copy_switch(struct copy_brick *brick)
{
static int version = 0;
MARS_DBG("power.button = %d\n", brick->power.button);
if (brick->power.button) {
mars_power_led_off((void*)brick, false);
if (!brick->thread) {
brick->copy_last = brick->copy_start;
brick->thread = kthread_create(_copy_thread, brick, "mars_copy%d", version++);
if (brick->thread) {
get_task_struct(brick->thread);
brick->trigger = true;
wake_up_process(brick->thread);
} else {
mars_power_led_off((void*)brick, true);
MARS_ERR("could not start copy thread\n");
}
}
} else {
mars_power_led_on((void*)brick, false);
if (brick->thread) {
kthread_stop_nowait(brick->thread);
put_task_struct(brick->thread);
brick->thread = NULL;
wake_up_interruptible(&brick->event);
}
}
return 0;
}
//////////////// object / aspect constructors / destructors ///////////////
static int copy_mref_aspect_init_fn(struct generic_aspect *_ini, void *_init_data)
{
struct copy_mref_aspect *ini = (void*)_ini;
(void)ini;
return 0;
}
static void copy_mref_aspect_exit_fn(struct generic_aspect *_ini, void *_init_data)
{
struct copy_mref_aspect *ini = (void*)_ini;
(void)ini;
}
MARS_MAKE_STATICS(copy);
////////////////////// brick constructors / destructors ////////////////////
static int copy_brick_construct(struct copy_brick *brick)
{
init_waitqueue_head(&brick->event);
sema_init(&brick->mutex, 1);
return 0;
}
static int copy_brick_destruct(struct copy_brick *brick)
{
return 0;
}
static int copy_output_construct(struct copy_output *output)
{
return 0;
}
static int copy_output_destruct(struct copy_output *output)
{
return 0;
}
///////////////////////// static structs ////////////////////////
static struct copy_brick_ops copy_brick_ops = {
.brick_switch = copy_switch,
};
static struct copy_output_ops copy_output_ops = {
.make_object_layout = copy_make_object_layout,
.mars_get_info = copy_get_info,
.mref_get = copy_ref_get,
.mref_put = copy_ref_put,
.mref_io = copy_ref_io,
};
const struct copy_input_type copy_input_type = {
.type_name = "copy_input",
.input_size = sizeof(struct copy_input),
};
static const struct copy_input_type *copy_input_types[] = {
&copy_input_type,
&copy_input_type,
&copy_input_type,
&copy_input_type,
};
const struct copy_output_type copy_output_type = {
.type_name = "copy_output",
.output_size = sizeof(struct copy_output),
.master_ops = &copy_output_ops,
.output_construct = &copy_output_construct,
.output_destruct = &copy_output_destruct,
.aspect_types = copy_aspect_types,
.layout_code = {
[BRICK_OBJ_MREF] = LAYOUT_ALL,
}
};
static const struct copy_output_type *copy_output_types[] = {
&copy_output_type,
};
const struct copy_brick_type copy_brick_type = {
.type_name = "copy_brick",
.brick_size = sizeof(struct copy_brick),
.max_inputs = 4,
.max_outputs = 1,
.master_ops = &copy_brick_ops,
.default_input_types = copy_input_types,
.default_output_types = copy_output_types,
.brick_construct = &copy_brick_construct,
.brick_destruct = &copy_brick_destruct,
};
EXPORT_SYMBOL_GPL(copy_brick_type);
////////////////// module init stuff /////////////////////////
static int __init init_copy(void)
{
MARS_INF("init_copy()\n");
return copy_register_brick_type();
}
static void __exit exit_copy(void)
{
MARS_INF("exit_copy()\n");
copy_unregister_brick_type();
}
MODULE_DESCRIPTION("MARS copy brick");
MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
MODULE_LICENSE("GPL");
module_init(init_copy);
module_exit(exit_copy);