[PATCH 25/50] mars: add new file include/linux/lib_log.h

Thomas Schoebel-Theuer
2014-07-01T22:02:01Z

include/linux/lib_log.h | 314 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 314 insertions(+)
create mode 100644 include/linux/lib_log.h

diff --git a/include/linux/lib_log.h b/include/linux/lib_log.h
new file mode 100644
index 0000000..ead2a72
--- /dev/null
+++ b/include/linux/lib_log.h
@@ -0,0 +1,314 @@
+/* (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG */
+
+/* Definitions for logfile format.
+ *
+ * This is meant for sharing between different transaction logger variants,
+ * and/or for sharing with userspace tools (e.g. logfile analyzers).
+ * TODO: factor out some remaining kernelspace issues.
+ */
+
+#ifndef LIB_LOG_H
+#define LIB_LOG_H
+
+#ifdef __KERNEL__
+#include <linux/xio.h>
+
+extern atomic_t global_aio_flying;
+#endif
+
+/* The following structure is memory-only.
+ * Transfers to disk are indirectly via the
+ * format conversion functions below.
+ * The advantage is that even newer disk formats can be parsed
+ * by old code (of course, not all information / features will be
+ * available then).
+ */
+#define log_header log_header_v1
+
+struct log_header_v1 {
+ struct timespec l_stamp;
+ struct timespec l_written;
+ loff_t l_pos;
+
+ short l_len;
+ short l_code;
+ unsigned int l_seq_nr;
+ int l_crc;
+};
+
+#define FORMAT_VERSION 1 /* version of disk format, currently there is no other one */
+
+#define CODE_UNKNOWN 0
+#define CODE_WRITE_NEW 1
+#define CODE_WRITE_OLD 2
+
+#define START_MAGIC 0xa8f7e908d9177957ll
+#define END_MAGIC 0x74941fb74ab5726dll
+
+#define START_OVERHEAD \
+ ( \
+ sizeof(START_MAGIC) + \
+ sizeof(char) + \
+ sizeof(char) + \
+ sizeof(short) + \
+ sizeof(struct timespec) + \
+ sizeof(loff_t) + \
+ sizeof(int) + \
+ sizeof(int) + \
+ sizeof(short) + \
+ sizeof(short) + \
+ 0 \
+ )
+
+#define END_OVERHEAD \
+ ( \
+ sizeof(END_MAGIC) + \
+ sizeof(int) + \
+ sizeof(char) + \
+ 3 + 4 /*spare*/ + \
+ sizeof(struct timespec) + \
+ 0 \
+ )
+
+#define OVERHEAD (START_OVERHEAD + END_OVERHEAD)
+
+/* TODO: make this bytesex-aware. */
+#define DATA_PUT(data, offset, val) \
+ do { \
+ *((typeof(val) *)((data)+offset)) = val; \
+ offset += sizeof(val); \
+ } while (0)
+
+#define DATA_GET(data, offset, val) \
+ do { \
+ val = *((typeof(val) *)((data)+offset)); \
+ offset += sizeof(val); \
+ } while (0)
+
+#define SCAN_TXT \
+"at file_pos = %lld file_offset = %d scan_offset = %d (%lld) test_offset = %d (%lld) restlen = %d: "
+#define SCAN_PAR \
+file_pos, file_offset, offset, file_pos + file_offset + offset, i, file_pos + file_offset + i, restlen
+
+static inline
+int log_scan(void *buf,
+ int len,
+ loff_t file_pos,
+ int file_offset,
+ bool sloppy,
+ struct log_header *lh,
+ void **payload,
+ int *payload_len,
+ unsigned int *seq_nr)
+{
+ bool dirty = false;
+ int offset;
+ int i;
+
+ *payload = NULL;
+ *payload_len = 0;
+
+ for (i = 0; i < len && i <= len - OVERHEAD; 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 = 0;
+ int found_offset;
+
+ offset = i;
+ if (unlikely(i > 0 && !sloppy)) {
+ XIO_ERR(SCAN_TXT "detected a hole / bad data\n", SCAN_PAR);
+ return -EBADMSG;
+ }
+
+ DATA_GET(buf, offset, start_magic);
+ if (unlikely(start_magic != START_MAGIC)) {
+ if (start_magic != 0)
+ dirty = true;
+ continue;
+ }
+
+ restlen = len - i;
+ if (unlikely(restlen < START_OVERHEAD)) {
+ XIO_WRN(SCAN_TXT "magic found, but restlen is too small\n", SCAN_PAR);
+ return -EAGAIN;
+ }
+
+ DATA_GET(buf, offset, format_version);
+ if (unlikely(format_version != FORMAT_VERSION)) {
+ XIO_ERR(SCAN_TXT "found unknown data format %d\n", SCAN_PAR, (int)format_version);
+ return -EBADMSG;
+ }
+ DATA_GET(buf, offset, valid_flag);
+ if (unlikely(!valid_flag)) {
+ XIO_WRN(SCAN_TXT "data is explicitly marked invalid (was there a short write?)\n", SCAN_PAR);
+ continue;
+ }
+ DATA_GET(buf, offset, total_len);
+ if (unlikely(total_len > restlen)) {
+ XIO_WRN(SCAN_TXT "total_len = %d but available data restlen = %d. Was the logfile truncated?\n",
+ SCAN_PAR,
+ total_len,
+ restlen);
+ return -EAGAIN;
+ }
+
+ 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);
+ offset += 2; /* skip spare */
+ offset += 4; /* skip spare */
+ DATA_GET(buf, offset, lh->l_code);
+ offset += 2; /* skip spare */
+
+ found_offset = offset;
+ offset += lh->l_len;
+
+ restlen = len - offset;
+ if (unlikely(restlen < END_OVERHEAD)) {
+ XIO_WRN(SCAN_TXT "restlen %d is too small\n", SCAN_PAR, restlen);
+ return -EAGAIN;
+ }
+
+ DATA_GET(buf, offset, end_magic);
+ if (unlikely(end_magic != END_MAGIC)) {
+ XIO_WRN(SCAN_TXT "bad end_magic 0x%llx, is the logfile truncated?\n", SCAN_PAR, end_magic);
+ return -EBADMSG;
+ }
+ DATA_GET(buf, offset, lh->l_crc);
+ DATA_GET(buf, offset, valid_copy);
+
+ if (unlikely(valid_copy != 1)) {
+ XIO_WRN(SCAN_TXT "found data marked as uncompleted / invalid, len = %d, valid_flag = %d\n",
+ SCAN_PAR,
+ lh->l_len,
+ (int)valid_copy);
+ return -EBADMSG;
+ }
+
+ /* skip spares */
+ offset += 3;
+
+ DATA_GET(buf, offset, lh->l_seq_nr);
+ DATA_GET(buf, offset, lh->l_written.tv_sec);
+ DATA_GET(buf, offset, lh->l_written.tv_nsec);
+
+ if (unlikely(lh->l_seq_nr > *seq_nr + 1 && lh->l_seq_nr && *seq_nr)) {
+ XIO_ERR(SCAN_TXT "record sequence number %u mismatch, expected was %u\n",
+ SCAN_PAR,
+ lh->l_seq_nr,
+ *seq_nr + 1);
+ return -EBADMSG;
+ } else if (unlikely(lh->l_seq_nr != *seq_nr + 1 && lh->l_seq_nr && *seq_nr)) {
+ XIO_WRN(SCAN_TXT "record sequence number %u mismatch, expected was %u\n",
+ SCAN_PAR,
+ lh->l_seq_nr,
+ *seq_nr + 1);
+ }
+ *seq_nr = lh->l_seq_nr;
+
+ if (lh->l_crc) {
+ unsigned char checksum[xio_digest_size];
+
+ xio_digest(checksum, buf + found_offset, lh->l_len);
+ if (unlikely(*(int *)checksum != lh->l_crc)) {
+ XIO_ERR(SCAN_TXT "data checksumming mismatch, length = %d\n", SCAN_PAR, lh->l_len);
+ return -EBADMSG;
+ }
+ }
+
+ /* last check */
+ if (unlikely(total_len != offset - i)) {
+ XIO_ERR(SCAN_TXT "internal size mismatch: %d != %d\n", SCAN_PAR, total_len, offset - i);
+ return -EBADMSG;
+ }
+
+ /* Success... */
+ *payload = buf + found_offset;
+ *payload_len = lh->l_len;
+
+ /* don't cry when nullbytes have been skipped */
+ if (i > 0 && dirty)
+ XIO_WRN(SCAN_TXT "skipped %d dirty bytes to find valid data\n", SCAN_PAR, i);
+
+ return offset;
+ }
+
+ XIO_ERR("could not find any useful data within len=%d bytes\n", len);
+ return -EAGAIN;
+}
+
+/**************************************************************************/
+
+#ifdef __KERNEL__
+
+/* Bookkeeping status between calls
+ */
+struct log_status {
+ /* interfacing */
+ wait_queue_head_t *signal_event;
+ /* tunables */
+ loff_t start_pos;
+ loff_t end_pos;
+
+ int align_size; /* alignment between requests */
+ int chunk_size; /* must be at least 8K (better 64k) */
+ int max_size; /* max payload length */
+ int io_prio;
+ bool do_crc;
+
+ /* informational */
+ atomic_t aio_flying;
+ int count;
+ loff_t log_pos;
+ struct timespec log_pos_stamp;
+
+ /* internal */
+ struct timespec tmp_pos_stamp;
+ struct xio_input *input;
+ struct xio_brick *brick;
+ struct xio_info info;
+ int offset;
+ int validflag_offset;
+ int reallen_offset;
+ int payload_offset;
+ int payload_len;
+ unsigned int seq_nr;
+ struct aio_object *log_aio;
+ struct aio_object *read_aio;
+
+ wait_queue_head_t event;
+ int error_code;
+ bool got;
+ bool do_free;
+ void *private;
+};
+
+void init_logst(struct log_status *logst, struct xio_input *input, loff_t start_pos, loff_t end_pos);
+void exit_logst(struct log_status *logst);
+
+void log_flush(struct log_status *logst);
+
+void *log_reserve(struct log_status *logst, struct log_header *lh);
+
+bool log_finalize(struct log_status *logst, int len, void (*endio)(void *private, int error), void *private);
+
+int log_read(struct log_status *logst, bool sloppy, struct log_header *lh, void **payload, int *payload_len);
+
+/***********************************************************************/
+
+/* init */
+
+extern int init_log_format(void);
+extern void exit_log_format(void);
+
+#endif
+#endif
--
2.0.0