From: Thomas Schoebel-Theuer <tst@schoebel-theuer.de>
To: linux-kernel@vger.kernel.org
Subject: [PATCH 26/50] mars: add new file drivers/block/mars/xio_bricks/lib_log.c
Date: Tue,  1 Jul 2014 23:47:06 +0200
Message-Id: <1404251250-22992-27-git-send-email-tst@schoebel-theuer.de>
In-Reply-To: <1404251250-22992-1-git-send-email-tst@schoebel-theuer.de>
References: <1404251250-22992-1-git-send-email-tst@schoebel-theuer.de>
Sender: linux-kernel-owner@vger.kernel.org

Signed-off-by: Thomas Schoebel-Theuer <tst@schoebel-theuer.de>
---
 drivers/block/mars/xio_bricks/lib_log.c | 500 ++++++++++++++++++++++++++++++++
 1 file changed, 500 insertions(+)
 create mode 100644 drivers/block/mars/xio_bricks/lib_log.c

diff --git a/drivers/block/mars/xio_bricks/lib_log.c b/drivers/block/mars/xio_bricks/lib_log.c
new file mode 100644
index 0000000..e068551
--- /dev/null
+++ b/drivers/block/mars/xio_bricks/lib_log.c
@@ -0,0 +1,500 @@
+/*  (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+
+#include <linux/lib_log.h>
+
+atomic_t global_aio_flying = ATOMIC_INIT(0);
+EXPORT_SYMBOL_GPL(global_aio_flying);
+
+void exit_logst(struct log_status *logst)
+{
+	int count;
+
+	log_flush(logst);
+
+	/*  TODO: replace by event */
+	count = 0;
+	while (atomic_read(&logst->aio_flying) > 0) {
+		if (!count++)
+			XIO_DBG("waiting for IO terminating...");
+		brick_msleep(500);
+	}
+	if (logst->read_aio) {
+		XIO_DBG("putting read_aio\n");
+		GENERIC_INPUT_CALL(logst->input, aio_put, logst->read_aio);
+		logst->read_aio = NULL;
+	}
+	if (logst->log_aio) {
+		XIO_DBG("putting log_aio\n");
+		GENERIC_INPUT_CALL(logst->input, aio_put, logst->log_aio);
+		logst->log_aio = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(exit_logst);
+
+void init_logst(struct log_status *logst, struct xio_input *input, loff_t start_pos, loff_t end_pos)
+{
+	exit_logst(logst);
+
+	memset(logst, 0, sizeof(struct log_status));
+
+	logst->input = input;
+	logst->brick = input->brick;
+	logst->start_pos = start_pos;
+	logst->log_pos = start_pos;
+	logst->end_pos = end_pos;
+	init_waitqueue_head(&logst->event);
+}
+EXPORT_SYMBOL_GPL(init_logst);
+
+#define XIO_LOG_CB_MAX			32
+
+struct log_cb_info {
+	struct aio_object *aio;
+	struct log_status *logst;
+	struct semaphore mutex;
+	atomic_t refcount;
+	int nr_cb;
+
+	/* make checkpatch.pl happy with a blank line - is this a false positive? */
+
+	void (*endios[XIO_LOG_CB_MAX])(void *private, int error);
+	void *privates[XIO_LOG_CB_MAX];
+};
+
+static
+void put_log_cb_info(struct log_cb_info *cb_info)
+{
+	if (atomic_dec_and_test(&cb_info->refcount))
+		brick_mem_free(cb_info);
+}
+
+static
+void _do_callbacks(struct log_cb_info *cb_info, int error)
+{
+	int i;
+
+	down(&cb_info->mutex);
+	for (i = 0; i < cb_info->nr_cb; i++) {
+		void (*end_fn)(void *private, int error);
+
+		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);
+}
+
+static
+void log_write_endio(struct generic_callback *cb)
+{
+	struct log_cb_info *cb_info = cb->cb_private;
+	struct log_status *logst;
+
+	LAST_CALLBACK(cb);
+	CHECK_PTR(cb_info, err);
+
+	logst = cb_info->logst;
+	CHECK_PTR(logst, done);
+
+	_do_callbacks(cb_info, cb->cb_error);
+
+done:
+	put_log_cb_info(cb_info);
+	atomic_dec(&logst->aio_flying);
+	atomic_dec(&global_aio_flying);
+	if (logst->signal_event)
+		wake_up_interruptible(logst->signal_event);
+
+	goto out_return;
+err:
+	XIO_FAT("internal pointer corruption\n");
+out_return:;
+}
+
+void log_flush(struct log_status *logst)
+{
+	struct aio_object *aio = logst->log_aio;
+	struct log_cb_info *cb_info;
+	int align_size;
+	int gap;
+
+	if (!aio || !logst->count)
+		goto out_return;
+	gap = 0;
+	align_size = (logst->align_size / PAGE_SIZE) * PAGE_SIZE;
+	if (align_size > 0) {
+		/*  round up to next alignment border */
+		int align_offset = logst->offset & (align_size-1);
+
+		if (align_offset > 0) {
+			int restlen = aio->io_len - logst->offset;
+
+			gap = align_size - align_offset;
+			if (unlikely(gap > restlen))
+				gap = restlen;
+		}
+	}
+	if (gap > 0) {
+		/*  don't leak information from kernelspace */
+		memset(aio->io_data + logst->offset, 0, gap);
+		logst->offset += gap;
+	}
+	aio->io_len = logst->offset;
+	memcpy(&logst->log_pos_stamp, &logst->tmp_pos_stamp, sizeof(logst->log_pos_stamp));
+
+	cb_info = logst->private;
+	logst->private = NULL;
+	SETUP_CALLBACK(aio, log_write_endio, cb_info);
+	cb_info->logst = logst;
+	aio->io_rw = 1;
+
+	atomic_inc(&logst->aio_flying);
+	atomic_inc(&global_aio_flying);
+
+	GENERIC_INPUT_CALL(logst->input, aio_io, aio);
+	GENERIC_INPUT_CALL(logst->input, aio_put, aio);
+
+	logst->log_pos += logst->offset;
+	logst->offset = 0;
+	logst->count = 0;
+	logst->log_aio = NULL;
+
+	put_log_cb_info(cb_info);
+out_return:;
+}
+EXPORT_SYMBOL_GPL(log_flush);
+
+void *log_reserve(struct log_status *logst, struct log_header *lh)
+{
+	struct log_cb_info *cb_info = logst->private;
+	struct aio_object *aio;
+	void *data;
+
+	short total_len = lh->l_len + OVERHEAD;
+	int offset;
+	int status;
+
+	if (unlikely(lh->l_len <= 0 || lh->l_len > logst->max_size)) {
+		XIO_ERR("trying to write %d bytes, max allowed = %d\n", lh->l_len, logst->max_size);
+		goto err;
+	}
+
+	aio = logst->log_aio;
+	if ((aio && total_len > aio->io_len - logst->offset)
+	   || !cb_info || cb_info->nr_cb >= XIO_LOG_CB_MAX) {
+		log_flush(logst);
+	}
+
+	aio = logst->log_aio;
+	if (!aio) {
+		if (unlikely(logst->private)) {
+			XIO_ERR("oops\n");
+			brick_mem_free(logst->private);
+		}
+		logst->private = brick_zmem_alloc(sizeof(struct log_cb_info));
+		cb_info = logst->private;
+		sema_init(&cb_info->mutex, 1);
+		atomic_set(&cb_info->refcount, 2);
+
+		aio = xio_alloc_aio(logst->brick);
+		cb_info->aio = aio;
+
+		aio->io_pos = logst->log_pos;
+		aio->io_len = logst->chunk_size ? logst->chunk_size : total_len;
+		aio->io_may_write = WRITE;
+		aio->io_prio = logst->io_prio;
+
+		for (;;) {
+			status = GENERIC_INPUT_CALL(logst->input, aio_get, aio);
+			if (likely(status >= 0))
+				break;
+			if (status != -ENOMEM && status != -EAGAIN) {
+				XIO_ERR("aio_get() failed, status = %d\n", status);
+				goto err_free;
+			}
+			brick_msleep(100);
+		}
+
+		if (unlikely(aio->io_len < total_len)) {
+			XIO_ERR("io_len = %d total_len = %d\n", aio->io_len, total_len);
+			goto put;
+		}
+
+		logst->offset = 0;
+		logst->log_aio = aio;
+	}
+
+	offset = logst->offset;
+	data = aio->io_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);
+	DATA_PUT(data, offset, (short)0); /*  spare */
+	DATA_PUT(data, offset, (int)0); /*  spare */
+	DATA_PUT(data, offset, lh->l_code);
+	DATA_PUT(data, offset, (short)0); /*  spare */
+
+	/*  remember the last timestamp */
+	memcpy(&logst->tmp_pos_stamp, &lh->l_stamp, sizeof(logst->tmp_pos_stamp));
+
+	logst->payload_offset = offset;
+	logst->payload_len = lh->l_len;
+
+	return data + offset;
+
+put:
+	GENERIC_INPUT_CALL(logst->input, aio_put, aio);
+	logst->log_aio = NULL;
+	return NULL;
+
+err_free:
+	obj_free(aio);
+	if (logst->private) {
+		/*  TODO: if callbacks are already registered, call them here with some error code */
+		brick_mem_free(logst->private);
+		logst->private = NULL;
+	}
+err:
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(log_reserve);
+
+bool log_finalize(struct log_status *logst, int len, void (*endio)(void *private, int error), void *private)
+{
+	struct aio_object *aio = logst->log_aio;
+	struct log_cb_info *cb_info = logst->private;
+	struct timespec now;
+	void *data;
+	int offset;
+	int restlen;
+	int nr_cb;
+	int crc;
+	bool ok = false;
+
+	CHECK_PTR(aio, err);
+
+	if (unlikely(len > logst->payload_len)) {
+		XIO_ERR("trying to write more than reserved (%d > %d)\n", len, logst->payload_len);
+		goto err;
+	}
+	restlen = aio->io_len - logst->offset;
+	if (unlikely(len + END_OVERHEAD > restlen)) {
+		XIO_ERR("trying to write more than available (%d > %d)\n", len, (int)(restlen - END_OVERHEAD));
+		goto err;
+	}
+	if (unlikely(!cb_info || cb_info->nr_cb >= XIO_LOG_CB_MAX)) {
+		XIO_ERR("too many endio() calls\n");
+		goto err;
+	}
+
+	data = aio->io_data;
+
+	crc = 0;
+	if (logst->do_crc) {
+		unsigned char checksum[xio_digest_size];
+
+		xio_digest(checksum, data + logst->payload_offset, len);
+		crc = *(int *)checksum;
+	}
+
+	/* Correct the length in the header.
+	 */
+	offset = logst->reallen_offset;
+	DATA_PUT(data, offset, (short)len);
+
+	/* Write the trailer.
+	 */
+	offset = logst->payload_offset + len;
+	DATA_PUT(data, offset, END_MAGIC);
+	DATA_PUT(data, offset, crc);
+	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, logst->seq_nr + 1);
+	get_lamport(&now);    /*  when the log entry was ready. */
+	DATA_PUT(data, offset, now.tv_sec);
+	DATA_PUT(data, offset, now.tv_nsec);
+
+	if (unlikely(offset > aio->io_len)) {
+		XIO_FAT("length calculation was wrong: %d > %d\n", offset, aio->io_len);
+		goto err;
+	}
+	logst->offset = offset;
+
+	/* This must come last. In case of incomplete
+	 * or even overlapping disk transfers, this indicates
+	 * the completeness / integrity of the payload at
+	 * the time of starting the transfer.
+	 */
+	offset = logst->validflag_offset;
+	DATA_PUT(data, offset, (char)1);
+
+	nr_cb = cb_info->nr_cb++;
+	cb_info->endios[nr_cb] = endio;
+	cb_info->privates[nr_cb] = private;
+
+	/*  report success */
+	logst->seq_nr++;
+	logst->count++;
+	ok = true;
+
+err:
+	return ok;
+}
+EXPORT_SYMBOL_GPL(log_finalize);
+
+static
+void log_read_endio(struct generic_callback *cb)
+{
+	struct log_status *logst = cb->cb_private;
+
+	LAST_CALLBACK(cb);
+	CHECK_PTR(logst, err);
+	logst->error_code = cb->cb_error;
+	logst->got = true;
+	wake_up_interruptible(&logst->event);
+	goto out_return;
+err:
+	XIO_FAT("internal pointer corruption\n");
+out_return:;
+}
+
+int log_read(struct log_status *logst, bool sloppy, struct log_header *lh, void **payload, int *payload_len)
+{
+	struct aio_object *aio;
+	int old_offset;
+	int status;
+
+restart:
+	status = 0;
+	aio = logst->read_aio;
+	if (!aio || logst->do_free) {
+		loff_t this_len;
+
+		if (aio) {
+			GENERIC_INPUT_CALL(logst->input, aio_put, aio);
+			logst->read_aio = NULL;
+			logst->log_pos += logst->offset;
+			logst->offset = 0;
+		}
+
+		this_len = logst->end_pos - logst->log_pos;
+		if (this_len > logst->chunk_size) {
+			this_len = logst->chunk_size;
+		} else if (unlikely(this_len <= 0)) {
+			XIO_ERR("tried bad IO len %lld, start_pos = %lld log_pos = %lld end_pos = %lld\n",
+				this_len,
+				logst->start_pos,
+				logst->log_pos,
+				logst->end_pos);
+			status = -EOVERFLOW;
+			goto done;
+		}
+
+		aio = xio_alloc_aio(logst->brick);
+		aio->io_pos = logst->log_pos;
+		aio->io_len = this_len;
+		aio->io_prio = logst->io_prio;
+
+		status = GENERIC_INPUT_CALL(logst->input, aio_get, aio);
+		if (unlikely(status < 0)) {
+			if (status != -ENODATA)
+				XIO_ERR("aio_get() failed, status = %d\n", status);
+			goto done_free;
+		}
+		if (unlikely(aio->io_len <= OVERHEAD)) { /*  EOF */
+			status = 0;
+			goto done_put;
+		}
+
+		SETUP_CALLBACK(aio, log_read_endio, logst);
+		aio->io_rw = READ;
+		logst->offset = 0;
+		logst->got = false;
+		logst->do_free = false;
+
+		GENERIC_INPUT_CALL(logst->input, aio_io, aio);
+
+		wait_event_interruptible_timeout(logst->event, logst->got, 60 * HZ);
+		status = -EIO;
+		if (!logst->got)
+			goto done_put;
+		status = logst->error_code;
+		if (status < 0)
+			goto done_put;
+		logst->read_aio = aio;
+	}
+
+	status = log_scan(aio->io_data + logst->offset,
+			  aio->io_len - logst->offset,
+			  aio->io_pos,
+			  logst->offset,
+			  sloppy,
+			  lh,
+			  payload,
+			  payload_len,
+			  &logst->seq_nr);
+
+	if (unlikely(status == 0)) {
+		XIO_ERR("bad logfile scan\n");
+		status = -EINVAL;
+	}
+	if (unlikely(status < 0))
+		goto done_put;
+
+	/*  memoize success */
+	logst->offset += status;
+	if (logst->offset + (logst->max_size + OVERHEAD) * 2 >= aio->io_len)
+		logst->do_free = true;
+
+done:
+	if (status == -ENODATA) {
+		/*  indicate EOF */
+		status = 0;
+	}
+	return status;
+
+done_put:
+	old_offset = logst->offset;
+	if (aio) {
+		GENERIC_INPUT_CALL(logst->input, aio_put, aio);
+		logst->read_aio = NULL;
+		logst->log_pos += logst->offset;
+		logst->offset = 0;
+	}
+	if (status == -EAGAIN && old_offset > 0)
+		goto restart;
+	goto done;
+
+done_free:
+	obj_free(aio);
+	logst->read_aio = NULL;
+	goto done;
+
+}
+EXPORT_SYMBOL_GPL(log_read);
+
+/***************** module init stuff ************************/
+
+int __init init_log_format(void)
+{
+	XIO_INF("init_log_format()\n");
+	return 0;
+}
+
+void exit_log_format(void)
+{
+	XIO_INF("exit_log_format()\n");
+}
-- 
2.0.0

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