Add checksumming to filesystem journal.

This will be used to check for consistency during log recovery.

diff --git a/bluesky/CMakeLists.txt b/bluesky/CMakeLists.txt
index 3b88d16..daaeccb 100644 (file)
--- a/bluesky/CMakeLists.txt
+++ b/bluesky/CMakeLists.txt
@@ -3,7 +3,7 @@ include_directories("${LIBS3_BUILD_DIR}/include" ${KVSTORE_DIR})
 link_directories("${LIBS3_BUILD_DIR}/lib" ${KVSTORE_DIR})
 
 add_library(bluesky SHARED
-            cache.c crypto.c debug.c dir.c file.c init.c inode.c log.c
+            cache.c crc32c.c crypto.c debug.c dir.c file.c init.c inode.c log.c
             serialize.c store.c store-bdb.c store-kv.cc store-multi.c
             store-s3.c util.c)
 add_executable(bluesky-test main.c)

diff --git a/bluesky/bluesky-private.h b/bluesky/bluesky-private.h
index 039e253..83a383e 100644 (file)
--- a/bluesky/bluesky-private.h
+++ b/bluesky/bluesky-private.h
@@ -152,6 +152,10 @@ void bluesky_file_drop_cached(BlueSkyInode *inode);
 
 /* Logging infrastructure for ensuring operations are persistently recorded to
  * disk. */
+#define BLUESKY_CRC32C_SEED (~(uint32_t)0)
+uint32_t crc32c(uint32_t crc, const char *buf, unsigned int length);
+uint32_t crc32c_finalize(uint32_t crc);
+
 struct _BlueSkyLog {
     char *log_directory;
     GAsyncQueue *queue;

diff --git a/bluesky/crc32c.c b/bluesky/crc32c.c
new file mode 100644 (file)
index 0000000..b29f18d
--- /dev/null
+++ b/bluesky/crc32c.c
@@ -0,0 +1,105 @@
+/* Blue Sky: File Systems in the Cloud
+ *
+ * This file implements the Castagnoli CRC-32 computation, and is taken from
+ * crypto/crc32c.c in the Linux kernel:
+ *
+ * Copyright (c) 2004 Cisco Systems, Inc.
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * Adapted by Michael Vrable to fit with BlueSky.
+ */
+
+#include <stdint.h>
+#include "bluesky-private.h"
+
+static const uint32_t crc32c_table[256] = {
+    0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
+    0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
+    0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
+    0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
+    0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
+    0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
+    0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
+    0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
+    0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
+    0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
+    0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
+    0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
+    0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
+    0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
+    0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
+    0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
+    0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
+    0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
+    0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
+    0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
+    0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
+    0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
+    0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
+    0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
+    0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
+    0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
+    0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
+    0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
+    0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
+    0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
+    0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
+    0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
+    0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
+    0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
+    0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
+    0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
+    0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
+    0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
+    0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
+    0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
+    0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
+    0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
+    0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
+    0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
+    0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
+    0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
+    0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
+    0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
+    0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
+    0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
+    0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
+    0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
+    0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
+    0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
+    0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
+    0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
+    0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
+    0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
+    0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
+    0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
+    0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
+    0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
+    0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
+    0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
+};
+
+/*
+ * Steps through buffer one byte at at time, calculates reflected
+ * crc using table.
+ */
+
+uint32_t crc32c(uint32_t crc, const char *buf, unsigned int length)
+{
+    const uint8_t *data = (const uint8_t *)buf;
+
+    while (length--)
+        crc = crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
+
+    return crc;
+}
+
+uint32_t crc32c_finalize(uint32_t crc)
+{
+    return ~GUINT32_TO_LE(crc);
+}

diff --git a/bluesky/log.c b/bluesky/log.c
index c3d0c2b..ee96976 100644 (file)
--- a/bluesky/log.c
+++ b/bluesky/log.c
@@ -37,6 +37,21 @@
 // no absolute guarantees on the size of a log segment.
 #define LOG_SEGMENT_SIZE (1 << 23)
 
+#define HEADER_MAGIC 0x676f4c0a
+#define FOOTER_MAGIC 0x2e435243
+
+struct log_header {
+    uint32_t magic;             // HEADER_MAGIC
+    uint64_t offset;            // Starting byte offset of the log header
+    uint32_t keysize;           // Size of the log key (bytes)
+    uint32_t size;              // Size of the data item (bytes)
+} __attribute__((packed));
+
+struct log_footer {
+    uint32_t magic;             // FOOTER_MAGIC
+    uint32_t crc;               // Computed from log_header to log_footer.magic
+} __attribute__((packed));
+
 static void writebuf(int fd, const char *buf, size_t len)
 {
     while (len > 0) {
@@ -97,14 +112,40 @@ static gpointer log_thread(gpointer d)
 
         BlueSkyLogItem *item = (BlueSkyLogItem *)g_async_queue_pop(log->queue);
         g_mutex_lock(item->lock);
+
+        off_t logsize = lseek(log->fd, 0, SEEK_CUR);
+        struct log_header header;
+        struct log_footer footer;
+
+        header.magic = GUINT32_TO_LE(HEADER_MAGIC);
+        header.offset = GUINT64_TO_LE(logsize);
+        header.keysize = GUINT32_TO_LE(strlen(item->key));
+        header.size = GUINT32_TO_LE(item->data->len);
+        footer.magic = GUINT32_TO_LE(FOOTER_MAGIC);
+
+        uint32_t crc = BLUESKY_CRC32C_SEED;
+
+        writebuf(log->fd, (const char *)&header, sizeof(header));
+        crc = crc32c(crc, (const char *)&header, sizeof(header));
+
         writebuf(log->fd, item->key, strlen(item->key));
+        crc = crc32c(crc, item->key, strlen(item->key));
+
         writebuf(log->fd, item->data->data, item->data->len);
+        crc = crc32c(crc, item->data->data, item->data->len);
+
+        crc = crc32c(crc, (const char *)&footer,
+                     sizeof(footer) - sizeof(uint32_t));
+        footer.crc = crc32c_finalize(crc);
+        writebuf(log->fd, (const char *)&footer, sizeof(footer));
+
         committed  = g_slist_prepend(committed, item);
 
         /* Force an fsync either if we will be closing this log segment and
          * opening a new file, or if there are no other log items currently
          * waiting to be written. */
-        off_t logsize = lseek(log->fd, 0, SEEK_CUR);
+        logsize += strlen(item->key) + item->data->len + sizeof(header) + sizeof(footer);
+
         if (logsize >= LOG_SEGMENT_SIZE
             || g_async_queue_length(log->queue) <= 0)
         {