mirror of https://github.com/schoebel/mars
364 lines
8.5 KiB
C
364 lines
8.5 KiB
C
// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include "log_format.h"
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void init_logst(struct log_status *logst, struct mars_input *input, struct mars_output *output, loff_t start_pos)
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{
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memset(logst, sizeof(*logst), 0);
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logst->input = input;
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logst->output = output;
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logst->log_pos = start_pos;
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init_waitqueue_head(&logst->event);
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}
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EXPORT_SYMBOL_GPL(init_logst);
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#define MARS_LOG_CB_MAX 16
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struct log_cb_info {
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int nr_endio;
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void (*endios[MARS_LOG_CB_MAX])(void *private, int error);
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void *privates[MARS_LOG_CB_MAX];
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};
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static
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void log_endio(struct generic_callback *cb)
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{
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struct log_cb_info *cb_info = cb->cb_private;
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int i;
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CHECK_PTR(cb_info, err);
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for (i = 0; i < cb_info->nr_endio; i++) {
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cb_info->endios[i](cb_info->privates[i], cb->cb_error);
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}
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kfree(cb_info);
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return;
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err:
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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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{
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struct mref_object *mref = logst->log_mref;
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struct generic_callback *cb;
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int gap;
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if (!mref)
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return;
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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);
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if (align_offset > 0) {
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gap = logst->align_size - align_offset;
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if (gap > logst->restlen) {
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gap = logst->restlen;
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}
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}
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}
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if (gap > 0) {
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// don't leak information from kernelspace
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memset(mref->ref_data + logst->offset, 0, gap);
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logst->offset += gap;
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}
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mref->ref_len = logst->offset;
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logst->log_pos += logst->offset;
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cb = &mref->_ref_cb;
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cb->cb_fn = log_endio;
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cb->cb_private = logst->private;
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logst->private = NULL;
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cb->cb_error = 0;
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cb->cb_prev = NULL;
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mref->ref_cb = cb;
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mref->ref_rw = 1;
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GENERIC_INPUT_CALL(logst->input, mref_io, mref);
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GENERIC_INPUT_CALL(logst->input, mref_put, mref);
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logst->offset = 0;
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logst->log_mref = NULL;
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}
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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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{
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struct log_cb_info *cb_info = logst->private;
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struct mref_object *mref;
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void *data;
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int total_len = lh->l_len + OVERHEAD;
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int offset;
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int status;
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MARS_DBG("reserving %d bytes at %lld\n", lh->l_len, logst->log_pos);
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if (total_len > logst->restlen || !cb_info || cb_info->nr_endio >= MARS_LOG_CB_MAX) {
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log_flush(logst);
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}
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mref = logst->log_mref;
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if (!mref) {
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int chunk_offset;
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int chunk_rest;
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if (unlikely(logst->private)) {
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MARS_ERR("oops\n");
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kfree(logst->private);
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}
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logst->private = kzalloc(sizeof(struct log_cb_info), GFP_MARS);
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if (unlikely(!logst->private)) {
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MARS_ERR("no memory\n");
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goto err;
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}
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mref = mars_alloc_mref(logst->output, &logst->ref_object_layout);
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if (unlikely(!mref)) {
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MARS_ERR("no mref\n");
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goto err;
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}
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mref->ref_pos = logst->log_pos;
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chunk_offset = logst->log_pos & (loff_t)(logst->chunk_size - 1);
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chunk_rest = logst->chunk_size - chunk_offset;
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if (chunk_rest < total_len) {
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mref->ref_pos += chunk_rest;
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chunk_rest = logst->chunk_size;
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}
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mref->ref_len = chunk_rest;
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if (mref->ref_len < total_len) {
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MARS_INF("not good: ref_len = %d total_len = %d\n", mref->ref_len, total_len);
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mref->ref_len = total_len;
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}
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mref->ref_may_write = WRITE;
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#if 0
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mref->ref_prio = MARS_PRIO_LOW;
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#endif
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status = GENERIC_INPUT_CALL(logst->input, mref_get, mref);
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if (unlikely(status < 0)) {
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MARS_ERR("mref_get() failed, status = %d\n", status);
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goto err_free;
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}
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if (unlikely(mref->ref_len < total_len)) {
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MARS_ERR("ref_len = %d total_len = %d\n", mref->ref_len, total_len);
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goto put;
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}
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logst->restlen = mref->ref_len;
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logst->offset = 0;
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logst->log_mref = mref;
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}
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offset = logst->offset;
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data = mref->ref_data;
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DATA_PUT(data, offset, START_MAGIC);
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DATA_PUT(data, offset, (char)FORMAT_VERSION);
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logst->validflag_offset = offset;
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DATA_PUT(data, offset, (char)0); // valid_flag
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DATA_PUT(data, offset, (short)0); // spare
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DATA_PUT(data, offset, total_len); // start of next header
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DATA_PUT(data, offset, lh->l_stamp.tv_sec);
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DATA_PUT(data, offset, lh->l_stamp.tv_nsec);
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DATA_PUT(data, offset, lh->l_pos);
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logst->reallen_offset = offset;
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DATA_PUT(data, offset, lh->l_len);
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DATA_PUT(data, offset, lh->l_code);
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logst->payload_offset = offset;
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logst->payload_len = lh->l_len;
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logst->offset = offset;
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return data + offset;
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put:
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GENERIC_INPUT_CALL(logst->input, mref_put, mref);
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return NULL;
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err_free:
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mars_free_mref(mref);
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err:
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return NULL;
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}
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EXPORT_SYMBOL_GPL(log_reserve);
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bool log_finalize(struct log_status *logst, int len, void (*endio)(void *private, int error), void *private)
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{
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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;
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void *data;
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int offset;
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int nr_endio;
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bool ok = false;
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CHECK_PTR(mref, err);
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if (unlikely(len > logst->restlen)) {
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MARS_ERR("trying to write more than reserved (%d > %d)\n", len, logst->restlen);
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goto err;
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}
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if (unlikely(!cb_info || cb_info->nr_endio >= MARS_LOG_CB_MAX)) {
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MARS_ERR("too many endio() calls\n");
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goto err;
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}
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data = mref->ref_data;
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/* Correct the length in the header.
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*/
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offset = logst->reallen_offset;
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DATA_PUT(data, offset, len);
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/* Write the trailer.
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*/
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offset = logst->payload_offset + len;
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DATA_PUT(data, offset, END_MAGIC);
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DATA_PUT(data, offset, (char)1); // valid_flag copy
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DATA_PUT(data, offset, (char)0); // spare
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DATA_PUT(data, offset, (short)0); // spare
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DATA_PUT(data, offset, (int)0); // spare
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get_lamport(&now); // when the log entry was ready.
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DATA_PUT(data, offset, now.tv_sec);
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DATA_PUT(data, offset, now.tv_nsec);
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logst->offset = offset;
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logst->restlen = mref->ref_len - offset;
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/* This must come last. In case of incomplete
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* or even operlapping disk transfers, this indicates
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* the completeness / integrity of the payload at
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* the time of starting the transfer.
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*/
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offset = logst->validflag_offset;
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DATA_PUT(data, offset, (char)1);
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nr_endio = cb_info->nr_endio++;
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cb_info->endios[nr_endio] = endio;
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cb_info->privates[nr_endio] = private;
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ok = true;
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err:
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return ok;
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}
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EXPORT_SYMBOL_GPL(log_finalize);
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static
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void read_endio(struct generic_callback *cb)
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{
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struct log_status *logst = cb->cb_private;
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CHECK_PTR(logst, err);
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logst->error_code = cb->cb_error;
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logst->got = true;
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wake_up_interruptible(&logst->event);
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return;
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err:
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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)
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{
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struct mref_object *mref = logst->read_mref;
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int i;
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int status = 0;
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if (!mref) {
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struct generic_callback *cb;
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int chunk_offset;
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int chunk_rest;
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mref = mars_alloc_mref(logst->output, &logst->ref_object_layout);
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if (unlikely(!mref)) {
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MARS_ERR("no mref\n");
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goto err;
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}
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mref->ref_pos = logst->log_pos;
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chunk_offset = logst->log_pos & (loff_t)(logst->chunk_size - 1);
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chunk_rest = logst->chunk_size - chunk_offset;
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mref->ref_len = chunk_rest;
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#if 0
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mref->ref_prio = MARS_PRIO_LOW;
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#endif
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status = GENERIC_INPUT_CALL(logst->input, mref_get, mref);
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if (unlikely(status < 0)) {
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MARS_ERR("mref_get() failed, status = %d\n", status);
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goto err_free;
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}
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cb = &mref->_ref_cb;
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cb->cb_fn = read_endio;
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cb->cb_private = logst;
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cb->cb_error = 0;
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cb->cb_prev = NULL;
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mref->ref_cb = cb;
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mref->ref_rw = 0;
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logst->offset = 0;
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logst->got = false;
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GENERIC_INPUT_CALL(logst->input, mref_io, mref);
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wait_event_interruptible_timeout(logst->event, logst->got, 60 * HZ);
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status = -EIO;
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if (!logst->got)
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goto err_free;
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status = logst->error_code;
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if (status < 0)
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goto err_free;
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logst->read_mref = mref;
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}
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for (i = logst->offset; i < mref->ref_len; ) {
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long long magic = 0;
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int startpos = i;
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DATA_GET(mref->ref_data, i, magic);
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if (magic == START_MAGIC) {
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int restlen = mref->ref_len - startpos;
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if (restlen < sizeof(struct log_header)) {
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MARS_ERR("magic found at pos %d, restlen = %d\n", startpos, restlen);
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}
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memcpy(lh, mref->ref_data + startpos, sizeof(struct log_header));
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//...
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break;
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}
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}
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return status;
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err_free:
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if (mref) {
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GENERIC_INPUT_CALL(logst->input, mref_put, mref);
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}
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err:
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return status;
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}
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EXPORT_SYMBOL_GPL(log_read);
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////////////////// module init stuff /////////////////////////
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static int __init init_log_format(void)
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{
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MARS_INF("init_log_format()\n");
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return 0;
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}
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static void __exit exit_log_format(void)
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{
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MARS_INF("exit_log_format()\n");
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}
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MODULE_DESCRIPTION("MARS log_format infrastucture");
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MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
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MODULE_LICENSE("GPL");
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module_init(init_log_format);
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module_exit(exit_log_format);
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