mars/lib_log.c

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14 KiB
C
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// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/bio.h>
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//#define BRICK_DEBUGGING
//#define MARS_DEBUGGING
//#define IO_DEBUGGING
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#include "lib_log.h"
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void exit_logst(struct log_status *logst)
{
int count = 0;
log_flush(logst);
while (atomic_read(&logst->mref_flying) > 0) {
if (!count++)
MARS_DBG("waiting for IO terminating...");
msleep(500);
}
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if (logst->read_mref) {
MARS_DBG("putting read_mref\n");
GENERIC_INPUT_CALL(logst->input, mref_put, logst->read_mref);
logst->read_mref = NULL;
}
if (logst->log_mref) {
MARS_DBG("putting log_mref\n");
GENERIC_INPUT_CALL(logst->input, mref_put, logst->log_mref);
logst->log_mref = NULL;
}
}
EXPORT_SYMBOL_GPL(exit_logst);
void init_logst(struct log_status *logst, struct mars_input *input, loff_t start_pos)
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{
exit_logst(logst);
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memset(logst, 0, sizeof(struct log_status));
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logst->input = input;
logst->brick = input->brick;
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logst->log_pos = start_pos;
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init_waitqueue_head(&logst->event);
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}
EXPORT_SYMBOL_GPL(init_logst);
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#define MARS_LOG_CB_MAX 32
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struct log_cb_info {
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struct mref_object *mref;
struct log_status *logst;
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struct semaphore mutex;
atomic_t refcount;
int nr_cb;
void (*preios[MARS_LOG_CB_MAX])(void *private);
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void (*endios[MARS_LOG_CB_MAX])(void *private, int error);
void *privates[MARS_LOG_CB_MAX];
};
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static
void put_log_cb_info(struct log_cb_info *cb_info)
{
if (atomic_dec_and_test(&cb_info->refcount)) {
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brick_mem_free(cb_info);
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}
}
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static
void _do_callbacks(struct log_cb_info *cb_info, int error, bool both)
{
int i;
down(&cb_info->mutex);
for (i = 0; i < cb_info->nr_cb; i++) {
void (*pre_fn)(void *private);
void (*end_fn)(void *private, int error);
pre_fn = cb_info->preios[i];
cb_info->preios[i] = NULL;
if (pre_fn) {
pre_fn(cb_info->privates[i]);
}
if (!both)
continue;
end_fn = cb_info->endios[i];
cb_info->endios[i] = NULL;
if (end_fn) {
end_fn(cb_info->privates[i], error);
}
}
up(&cb_info->mutex);
}
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static
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void log_write_endio(struct generic_callback *cb)
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{
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struct log_cb_info *cb_info = cb->cb_private;
struct log_status *logst;
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CHECK_PTR(cb_info, err);
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if (cb_info->mref) {
mars_trace(cb_info->mref, "log_endio");
mars_log_trace(cb_info->mref);
}
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logst = cb_info->logst;
CHECK_PTR(logst, done);
atomic_dec(&logst->mref_flying);
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MARS_IO("nr_cb = %d\n", cb_info->nr_cb);
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_do_callbacks(cb_info, cb->cb_error, true);
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done:
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put_log_cb_info(cb_info);
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return;
err:
MARS_FAT("internal pointer corruption\n");
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}
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void log_flush(struct log_status *logst)
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{
struct mref_object *mref = logst->log_mref;
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struct log_cb_info *cb_info;
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int gap;
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if (!mref || !logst->count)
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return;
gap = 0;
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if (logst->align_size > 0) {
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// round up to next alignment border
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int align_offset = logst->offset & (logst->align_size-1);
if (align_offset > 0) {
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int restlen = mref->ref_len - logst->offset;
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gap = logst->align_size - align_offset;
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if (gap > restlen) {
gap = restlen;
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}
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}
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}
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if (gap > 0) {
// don't leak information from kernelspace
memset(mref->ref_data + logst->offset, 0, gap);
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logst->offset += gap;
}
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mref->ref_len = logst->offset;
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logst->log_pos += logst->offset;
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cb_info = logst->private;
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logst->private = NULL;
SETUP_CALLBACK(mref, log_write_endio, cb_info);
cb_info->logst = logst;
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mref->ref_rw = 1;
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mars_trace(mref, "log_flush");
atomic_inc(&logst->mref_flying);
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_do_callbacks(cb_info, 0, false);
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GENERIC_INPUT_CALL(logst->input, mref_io, mref);
GENERIC_INPUT_CALL(logst->input, mref_put, mref);
logst->offset = 0;
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logst->count = 0;
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logst->log_mref = NULL;
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put_log_cb_info(cb_info);
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}
EXPORT_SYMBOL_GPL(log_flush);
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void *log_reserve(struct log_status *logst, struct log_header *lh)
{
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struct log_cb_info *cb_info = logst->private;
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struct mref_object *mref;
void *data;
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short total_len = lh->l_len + OVERHEAD;
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int offset;
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int status;
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MARS_IO("reserving %d bytes at %lld\n", lh->l_len, logst->log_pos);
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mref = logst->log_mref;
if ((mref && total_len > mref->ref_len - logst->offset)
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|| !cb_info || cb_info->nr_cb >= MARS_LOG_CB_MAX) {
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log_flush(logst);
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}
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mref = logst->log_mref;
if (!mref) {
if (unlikely(logst->private)) {
MARS_ERR("oops\n");
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brick_mem_free(logst->private);
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}
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logst->private = brick_zmem_alloc(sizeof(struct log_cb_info));
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if (unlikely(!logst->private)) {
MARS_ERR("no memory\n");
goto err;
}
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cb_info = logst->private;
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sema_init(&cb_info->mutex, 1);
atomic_set(&cb_info->refcount, 2);
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mref = mars_alloc_mref(logst->brick);
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if (unlikely(!mref)) {
MARS_ERR("no mref\n");
goto err;
}
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cb_info->mref = mref;
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mref->ref_pos = logst->log_pos;
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mref->ref_len = total_len;
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mref->ref_may_write = WRITE;
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mref->ref_prio = logst->io_prio;
if (logst->chunk_size > 0) {
int chunk_offset;
int chunk_rest;
chunk_offset = logst->log_pos & (loff_t)(logst->chunk_size - 1);
chunk_rest = logst->chunk_size - chunk_offset;
while (chunk_rest < total_len) {
chunk_rest += logst->chunk_size;
}
mref->ref_len = chunk_rest;
}
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for (;;) {
status = GENERIC_INPUT_CALL(logst->input, mref_get, mref);
if (likely(status >= 0)) {
break;
}
if (status != -ENOMEM && status != -EAGAIN) {
MARS_ERR("mref_get() failed, status = %d\n", status);
goto err_free;
}
msleep(100);
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}
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mars_trace(mref, "log_start");
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if (unlikely(mref->ref_len < total_len)) {
MARS_ERR("ref_len = %d total_len = %d\n", mref->ref_len, total_len);
goto put;
}
logst->offset = 0;
logst->log_mref = mref;
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}
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offset = logst->offset;
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data = mref->ref_data;
DATA_PUT(data, offset, START_MAGIC);
DATA_PUT(data, offset, (char)FORMAT_VERSION);
logst->validflag_offset = offset;
DATA_PUT(data, offset, (char)0); // valid_flag
DATA_PUT(data, offset, total_len); // start of next header
DATA_PUT(data, offset, lh->l_stamp.tv_sec);
DATA_PUT(data, offset, lh->l_stamp.tv_nsec);
DATA_PUT(data, offset, lh->l_pos);
logst->reallen_offset = offset;
DATA_PUT(data, offset, lh->l_len);
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DATA_PUT(data, offset, lh->l_extra_len);
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DATA_PUT(data, offset, lh->l_code);
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DATA_PUT(data, offset, lh->l_extra);
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logst->payload_offset = offset;
logst->payload_len = lh->l_len;
return data + offset;
put:
GENERIC_INPUT_CALL(logst->input, mref_put, mref);
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logst->log_mref = NULL;
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return NULL;
err_free:
mars_free_mref(mref);
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if (logst->private) {
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// TODO: if callbacks are already registered, call them here with some error code
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brick_mem_free(logst->private);
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logst->private = NULL;
}
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err:
return NULL;
}
EXPORT_SYMBOL_GPL(log_reserve);
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bool log_finalize(struct log_status *logst, int len, void (*preio)(void *private), void (*endio)(void *private, int error), void *private)
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{
struct mref_object *mref = logst->log_mref;
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struct log_cb_info *cb_info = logst->private;
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struct timespec now;
void *data;
int offset;
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int restlen;
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int nr_cb;
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bool ok = false;
CHECK_PTR(mref, err);
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if (unlikely(len > logst->payload_len)) {
MARS_ERR("trying to write more than reserved (%d > %d)\n", len, logst->payload_len);
goto err;
}
restlen = mref->ref_len - logst->offset;
if (unlikely(len + END_OVERHEAD > restlen)) {
MARS_ERR("trying to write more than available (%d > %d)\n", len, (int)(restlen - END_OVERHEAD));
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goto err;
}
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if (unlikely(!cb_info || cb_info->nr_cb >= MARS_LOG_CB_MAX)) {
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MARS_ERR("too many endio() calls\n");
goto err;
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}
data = mref->ref_data;
/* Correct the length in the header.
*/
offset = logst->reallen_offset;
DATA_PUT(data, offset, len);
/* Write the trailer.
*/
offset = logst->payload_offset + len;
DATA_PUT(data, offset, END_MAGIC);
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DATA_PUT(data, offset, (int)0); // crc
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DATA_PUT(data, offset, (char)1); // valid_flag copy
DATA_PUT(data, offset, (char)0); // spare
DATA_PUT(data, offset, (short)0); // spare
DATA_PUT(data, offset, (int)0); // spare
get_lamport(&now); // when the log entry was ready.
DATA_PUT(data, offset, now.tv_sec);
DATA_PUT(data, offset, now.tv_nsec);
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if (unlikely(offset > mref->ref_len)) {
MARS_ERR("length calculation was wrong: %d > %d\n", offset, mref->ref_len);
goto err;
}
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logst->offset = offset;
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/* This must come last. In case of incomplete
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* or even overlapping disk transfers, this indicates
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* the completeness / integrity of the payload at
* the time of starting the transfer.
*/
offset = logst->validflag_offset;
DATA_PUT(data, offset, (char)1);
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nr_cb = cb_info->nr_cb++;
cb_info->preios[nr_cb] = preio;
cb_info->endios[nr_cb] = endio;
cb_info->privates[nr_cb] = private;
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logst->count++;
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ok = true;
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err:
return ok;
}
EXPORT_SYMBOL_GPL(log_finalize);
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static
int log_scan(void *buf, int len, struct log_header *lh, void **payload, int *payload_len)
{
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bool dirty = false;
int offset;
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int i;
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*payload = NULL;
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*payload_len = 0;
for (i = 0; i < len; i += sizeof(long)) {
long long start_magic;
char format_version;
char valid_flag;
short total_len;
long long end_magic;
char valid_copy;
int restlen;
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int found_offset;
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offset = i;
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DATA_GET(buf, offset, start_magic);
if (start_magic != START_MAGIC) {
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if (start_magic != 0)
dirty = true;
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continue;
}
restlen = len - i;
if (restlen < START_OVERHEAD) {
MARS_WRN("magic found at offset %d, but restlen %d is too small\n", i, restlen);
return -EBADMSG;
}
DATA_GET(buf, offset, format_version);
if (format_version != FORMAT_VERSION) {
MARS_WRN("found unknown data format %d at offset %d\n", (int)format_version, i);
continue;
}
DATA_GET(buf, offset, valid_flag);
if (!valid_flag) {
MARS_WRN("data at offset %d is marked invalid (was there a short write?)\n", i);
continue;
}
DATA_GET(buf, offset, total_len);
if (total_len > restlen) {
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MARS_WRN("data at offset %d is longer than expected, total_len = %d restlen = %d\n", i, total_len, restlen);
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return -EAGAIN;
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}
memset(lh, 0, sizeof(struct log_header));
DATA_GET(buf, offset, lh->l_stamp.tv_sec);
DATA_GET(buf, offset, lh->l_stamp.tv_nsec);
DATA_GET(buf, offset, lh->l_pos);
DATA_GET(buf, offset, lh->l_len);
DATA_GET(buf, offset, lh->l_extra_len);
DATA_GET(buf, offset, lh->l_code);
DATA_GET(buf, offset, lh->l_extra);
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found_offset = offset;
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offset += lh->l_len;
restlen = len - offset;
if (restlen < END_OVERHEAD) {
MARS_WRN("magic found at offset %d, but restlen %d is too small\n", i, restlen);
continue;
}
DATA_GET(buf, offset, end_magic);
if (end_magic != END_MAGIC) {
MARS_WRN("bad end_magic 0x%llx\n", end_magic);
continue;
}
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DATA_GET(buf, offset, lh->l_crc);
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DATA_GET(buf, offset, valid_copy);
if (valid_copy != 1) {
MARS_WRN("found uncompleted / invalid data at %d len = %d (valid_flag = %d)\n", i, lh->l_len, (int)valid_copy);
continue;
}
// skip spares
offset += 3 + 4;
DATA_GET(buf, offset, lh->l_written.tv_sec);
DATA_GET(buf, offset, lh->l_written.tv_nsec);
// last check
if (total_len != offset - i) {
MARS_WRN("size mismatch at offset %d: %d != %d\n", i, total_len, offset - i);
// just warn, but no consequences: better use the data, it has been checked by lots of magics
}
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// Success...
*payload = buf + found_offset;
*payload_len = lh->l_len;
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goto done;
}
offset = i;
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done:
// don't cry when nullbytes have been skipped
if (i > 0 && dirty) {
MARS_WRN("skipped %d dirty bytes at offset %d to find valid data\n", i, offset);
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}
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return offset;
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}
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static
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void log_read_endio(struct generic_callback *cb)
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{
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struct log_status *logst = cb->cb_private;
CHECK_PTR(logst, err);
logst->error_code = cb->cb_error;
logst->got = true;
wake_up_interruptible(&logst->event);
return;
err:
MARS_FAT("internal pointer corruption\n");
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}
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int log_read(struct log_status *logst, struct log_header *lh, void **payload, int *payload_len)
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{
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struct mref_object *mref;
int status;
restart:
status = 0;
mref = logst->read_mref;
if (!mref || logst->do_free) {
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int chunk_offset;
int chunk_rest;
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if (mref) {
logst->log_pos += logst->offset;
GENERIC_INPUT_CALL(logst->input, mref_put, mref);
logst->read_mref = NULL;
logst->offset = 0;
}
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mref = mars_alloc_mref(logst->brick);
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if (unlikely(!mref)) {
MARS_ERR("no mref\n");
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goto done;
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}
mref->ref_pos = logst->log_pos;
chunk_offset = logst->log_pos & (loff_t)(logst->chunk_size - 1);
chunk_rest = logst->chunk_size - chunk_offset;
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mref->ref_len = chunk_rest + logst->chunk_size * 4;
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MARS_IO("log_pos = %lld chunk_offset = %d chunk_rest = %d ref_len = %d\n", logst->log_pos, chunk_offset, chunk_rest, mref->ref_len);
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mref->ref_prio = logst->io_prio;
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status = GENERIC_INPUT_CALL(logst->input, mref_get, mref);
if (unlikely(status < 0)) {
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if (status != -ENODATA) {
MARS_ERR("mref_get() failed, status = %d\n", status);
}
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goto done_free;
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}
SETUP_CALLBACK(mref, log_read_endio, logst);
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mref->ref_rw = READ;
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logst->offset = 0;
logst->got = false;
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logst->do_free = false;
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GENERIC_INPUT_CALL(logst->input, mref_io, mref);
wait_event_interruptible_timeout(logst->event, logst->got, 60 * HZ);
status = -EIO;
if (!logst->got)
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goto done_put;
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status = logst->error_code;
if (status < 0)
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goto done_put;
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logst->read_mref = mref;
}
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status = log_scan(mref->ref_data + logst->offset, mref->ref_len - logst->offset, lh, payload, payload_len);
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if (unlikely(status == 0)) {
MARS_ERR("bad logfile scan\n");
status = -EINVAL;
}
if (unlikely(status < 0)) {
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MARS_IO("ref_len = %d offset = %d status = %d\n", mref->ref_len, logst->offset, status);
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goto done_put;
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}
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// memorize success
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logst->offset += status;
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if (logst->offset > mref->ref_len - logst->chunk_size) {
logst->do_free = true;
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}
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done:
if (status == -ENODATA) {
status = 0; // indicates EOF
}
return status;
done_put:
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if (mref) {
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logst->log_pos += logst->offset;
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GENERIC_INPUT_CALL(logst->input, mref_put, mref);
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logst->read_mref = NULL;
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logst->offset = 0;
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}
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if (status == -EAGAIN && logst->offset > 0) {
goto restart;
}
goto done;
done_free:
if (mref) {
mars_free_mref(mref);
}
logst->read_mref = NULL;
goto done;
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}
EXPORT_SYMBOL_GPL(log_read);
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////////////////// module init stuff /////////////////////////
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int __init init_log_format(void)
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{
MARS_INF("init_log_format()\n");
return 0;
}
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void __exit exit_log_format(void)
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{
MARS_INF("exit_log_format()\n");
}
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#ifndef CONFIG_MARS_HAVE_BIGMODULE
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MODULE_DESCRIPTION("MARS log_format infrastucture");
MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
MODULE_LICENSE("GPL");
module_init(init_log_format);
module_exit(exit_log_format);
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#endif