tromcho.net/dump_journal.cpp

// Copyright (c) Vitaliy Filippov, 2019+
// License: VNPL-1.1 (see README.md for details)

#define _LARGEFILE64_SOURCE
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdint.h>
#include <malloc.h>
#include <linux/fs.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <stdio.h>

#include "blockstore_impl.h"
#include "crc32c.h"

struct journal_dump_t
{
    char *journal_device;
    uint32_t journal_block;
    uint64_t journal_offset;
    uint64_t journal_len;
    uint64_t journal_pos;
    bool all;
    bool started;
    int fd;
    uint32_t crc32_last;

    int dump_block(void *buf);
};

int main(int argc, char *argv[])
{
    journal_dump_t self = { 0 };
    int b = 1;
    if (argc >= 2 && !strcmp(argv[1], "--all"))
    {
        self.all = true;
        b = 2;
    }
    if (argc < b+4)
    {
        printf("USAGE: %s [--all] <journal_file> <journal_block_size> <offset> <size>\n", argv[0]);
        return 1;
    }
    self.journal_device = argv[b];
    self.journal_block = strtoul(argv[b+1], NULL, 10);
    self.journal_offset = strtoull(argv[b+2], NULL, 10);
    self.journal_len = strtoull(argv[b+3], NULL, 10);
    if (self.journal_block < MEM_ALIGNMENT || (self.journal_block % MEM_ALIGNMENT) ||
        self.journal_block > 128*1024)
    {
        printf("Invalid journal block size\n");
        return 1;
    }
    self.fd = open(self.journal_device, O_DIRECT|O_RDONLY);
    if (self.fd == -1)
    {
        printf("Failed to open journal\n");
        return 1;
    }
    void *data = memalign(MEM_ALIGNMENT, self.journal_block);
    self.journal_pos = 0;
    if (self.all)
    {
        while (self.journal_pos < self.journal_len)
        {
            int r = pread(self.fd, data, self.journal_block, self.journal_offset+self.journal_pos);
            assert(r == self.journal_block);
            uint64_t s;
            for (s = 0; s < self.journal_block; s += 8)
            {
                if (*((uint64_t*)(data+s)) != 0)
                    break;
            }
            if (s == self.journal_block)
            {
                printf("offset %08lx: zeroes\n", self.journal_pos);
                self.journal_pos += self.journal_block;
            }
            else if (((journal_entry*)data)->magic == JOURNAL_MAGIC)
            {
                printf("offset %08lx:\n", self.journal_pos);
                self.dump_block(data);
            }
            else
            {
                printf("offset %08lx: no magic in the beginning, looks like random data (pattern=%lx)\n", self.journal_pos, *((uint64_t*)data));
                self.journal_pos += self.journal_block;
            }
        }
    }
    else
    {
        int r = pread(self.fd, data, self.journal_block, self.journal_offset+self.journal_pos);
        assert(r == self.journal_block);
        journal_entry *je = (journal_entry*)(data);
        if (je->magic != JOURNAL_MAGIC || je->type != JE_START || je_crc32(je) != je->crc32)
        {
            printf("offset %08lx: journal superblock is invalid\n", self.journal_pos);
        }
        else
        {
            printf("offset %08lx:\n", self.journal_pos);
            self.dump_block(data);
            self.started = false;
            self.journal_pos = je->start.journal_start;
            while (1)
            {
                if (self.journal_pos >= self.journal_len)
                    self.journal_pos = self.journal_block;
                r = pread(self.fd, data, self.journal_block, self.journal_offset+self.journal_pos);
                assert(r == self.journal_block);
                printf("offset %08lx:\n", self.journal_pos);
                r = self.dump_block(data);
                if (r <= 0)
                {
                    printf("end of the journal\n");
                    break;
                }
            }
        }
    }
    free(data);
    close(self.fd);
    return 0;
}

int journal_dump_t::dump_block(void *buf)
{
    uint32_t pos = 0;
    journal_pos += journal_block;
    int entry = 0;
    bool wrapped = false;
    while (pos < journal_block)
    {
        journal_entry *je = (journal_entry*)(buf + pos);
        if (je->magic != JOURNAL_MAGIC || je->type < JE_MIN || je->type > JE_MAX ||
            !all && started && je->crc32_prev != crc32_last)
        {
            break;
        }
        bool crc32_valid = je_crc32(je) == je->crc32;
        if (!all && !crc32_valid)
        {
            break;
        }
        started = true;
        crc32_last = je->crc32;
        printf("entry % 3d: crc32=%08x %s prev=%08x ", entry, je->crc32, (crc32_valid ? "(valid)" : "(invalid)"), je->crc32_prev);
        if (je->type == JE_START)
        {
            printf("je_start start=%08lx\n", je->start.journal_start);
        }
        else if (je->type == JE_SMALL_WRITE || je->type == JE_SMALL_WRITE_INSTANT)
        {
            printf(
                "je_small_write%s oid=%lx:%lx ver=%lu offset=%u len=%u loc=%08lx",
                je->type == JE_SMALL_WRITE_INSTANT ? "_instant" : "",
                je->small_write.oid.inode, je->small_write.oid.stripe,
                je->small_write.version, je->small_write.offset, je->small_write.len,
                je->small_write.data_offset
            );
            if (journal_pos + je->small_write.len > journal_len)
            {
                // data continues from the beginning of the journal
                journal_pos = journal_block;
                wrapped = true;
            }
            if (journal_pos != je->small_write.data_offset)
            {
                printf(" (mismatched, calculated = %lu)", journal_pos);
            }
            journal_pos += je->small_write.len;
            if (journal_pos >= journal_len)
            {
                journal_pos = journal_block;
                wrapped = true;
            }
            uint32_t data_crc32 = 0;
            void *data = memalign(MEM_ALIGNMENT, je->small_write.len);
            assert(pread(fd, data, je->small_write.len, journal_offset+je->small_write.data_offset) == je->small_write.len);
            data_crc32 = crc32c(0, data, je->small_write.len);
            free(data);
            printf(
                " data_crc32=%08x%s", je->small_write.crc32_data,
                (data_crc32 != je->small_write.crc32_data) ? " (invalid)" : " (valid)"
            );
            printf("\n");
        }
        else if (je->type == JE_BIG_WRITE || je->type == JE_BIG_WRITE_INSTANT)
        {
            printf(
                "je_big_write%s oid=%lx:%lx ver=%lu loc=%08lx\n",
                je->type == JE_BIG_WRITE_INSTANT ? "_instant" : "",
                je->big_write.oid.inode, je->big_write.oid.stripe, je->big_write.version, je->big_write.location
            );
        }
        else if (je->type == JE_STABLE)
        {
            printf("je_stable oid=%lx:%lx ver=%lu\n", je->stable.oid.inode, je->stable.oid.stripe, je->stable.version);
        }
        else if (je->type == JE_ROLLBACK)
        {
            printf("je_rollback oid=%lx:%lx ver=%lu\n", je->rollback.oid.inode, je->rollback.oid.stripe, je->rollback.version);
        }
        else if (je->type == JE_DELETE)
        {
            printf("je_delete oid=%lx:%lx ver=%lu\n", je->del.oid.inode, je->del.oid.stripe, je->del.version);
        }
        pos += je->size;
        entry++;
    }
    if (wrapped)
    {
        journal_pos = journal_len;
    }
    return entry;
}