battfs.c

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#include "battfs.h"
#include "cfg/cfg_battfs.h"
#include <cfg/debug.h>
#include <cfg/macros.h> /* MIN, MAX */
#include <cfg/test.h>
#include <cpu/byteorder.h> /* cpu_to_xx */

#define LOG_LEVEL       BATTFS_LOG_LEVEL
#define LOG_FORMAT      BATTFS_LOG_FORMAT
#include <cfg/log.h>

#include <string.h> /* memset, memmove */

#if LOG_LEVEL >= LOG_LVL_INFO
static void dumpPageArray(struct BattFsSuper *disk)
{
    kprintf("Page array dump, free_page_start %d:", disk->free_page_start);
    for (pgcnt_t i = 0; i < disk->dev->blk_cnt; i++)
    {
        if (!(i % 16))
            kputchar('\n');
        kprintf("%04d ", disk->page_array[i]);
    }
    kputchar('\n');
}
#endif

INLINE void battfs_to_disk(struct BattFsPageHeader *hdr, uint8_t *buf)
{
    STATIC_ASSERT(BATTFS_HEADER_LEN == 12);
    buf[0] = hdr->inode;

    buf[1] = hdr->fill;
    buf[2] = hdr->fill >> 8;

    buf[3] = hdr->pgoff;
    buf[4] = hdr->pgoff >> 8;

    /*
     * Sequence number is 40 bits long.
     * No need to take care of wraparonds: the memory will die first!
     */
    buf[5] = hdr->seq;
    buf[6] = hdr->seq >> 8;
    buf[7] = hdr->seq >> 16;
    buf[8] = hdr->seq >> 24;
    buf[9] = hdr->seq >> 32;

    /*
     * This field must be the last one!
     * This is needed because if the page is only partially
     * written, we can use this to detect it.
     */
    buf[10] = hdr->fcs;
    buf[11] = hdr->fcs >> 8;
}

INLINE void disk_to_battfs(uint8_t *buf, struct BattFsPageHeader *hdr)
{
    STATIC_ASSERT(BATTFS_HEADER_LEN == 12);
    hdr->inode = buf[0];
    hdr->fill = buf[2] << 8 | buf[1];
    hdr->pgoff = buf[4] << 8 | buf[3];
    hdr->seq = (seq_t)buf[9] << 32 | (seq_t)buf[8] << 24 | (seq_t)buf[7] << 16 | buf[6] << 8 | buf[5];
    hdr->fcs = buf[11] << 8 | buf[10];
}

static fcs_t computeFcs(struct BattFsPageHeader *hdr)
{
    uint8_t buf[BATTFS_HEADER_LEN];
    fcs_t cks;

    battfs_to_disk(hdr, buf);
    rotating_init(&cks);
    /* fcs is at the end of whole header */
    rotating_update(buf, BATTFS_HEADER_LEN - sizeof(fcs_t), &cks);
    return cks;
}

static bool readHdr(struct BattFsSuper *disk, pgcnt_t page, struct BattFsPageHeader *hdr)
{
    uint8_t buf[BATTFS_HEADER_LEN];

    /*
     * Read header from disk.
     * Header is actually a footer, and so
     * resides at page end.
     */
    if (kblock_read(disk->dev, page, buf, disk->data_size, BATTFS_HEADER_LEN)
        != BATTFS_HEADER_LEN)
    {
        LOG_ERR("page[%d]\n", page);
        return false;
    }

    /* Fill header */
    disk_to_battfs(buf, hdr);

    return true;
}

static bool writeHdr(struct BattFsSuper *disk, pgcnt_t page, struct BattFsPageHeader *hdr)
{
    uint8_t buf[BATTFS_HEADER_LEN];

    #warning FIXME:refactor computeFcs to save time and stack
    hdr->fcs = computeFcs(hdr);
    /* Fill buffer */
    battfs_to_disk(hdr, buf);

    /*
     * write header to disk.
     * Header is actually a footer, and so
     * resides at page end.
     */
    if (kblock_write(disk->dev, page, buf, disk->data_size, BATTFS_HEADER_LEN)
        != BATTFS_HEADER_LEN)
    {
        LOG_ERR("writing to buffer\n");
        return false;
    }
    return true;
}


static pgcnt_t countPages(pgoff_t *filelen_table, inode_t inode)
{
    pgcnt_t cnt = 0;

    for (inode_t i = 0; i < inode; i++)
        cnt += filelen_table[i];

    return cnt;
}

static void movePages(struct BattFsSuper *disk, pgcnt_t src, int offset)
{
    pgcnt_t dst = src + offset;
    LOG_INFO("src %d, offset %d, size %d\n", src, offset, (unsigned int)((disk->dev->blk_cnt - MAX(dst, src)) * sizeof(pgcnt_t)));
    memmove(&disk->page_array[dst], &disk->page_array[src], (disk->dev->blk_cnt - MAX(dst, src)) * sizeof(pgcnt_t));

    if (offset < 0)
    {
        /* Fill empty space in array with sentinel */
        for (pgcnt_t page = disk->dev->blk_cnt + offset; page < disk->dev->blk_cnt; page++)
            disk->page_array[page] = PAGE_UNSET_SENTINEL;
    }
}

static bool countDiskFilePages(struct BattFsSuper *disk, pgoff_t *filelen_table)
{
    BattFsPageHeader hdr;
    disk->free_page_start = 0;

    /* Count the number of disk page per file */
    for (pgcnt_t page = 0; page < disk->dev->blk_cnt; page++)
    {
        if (!readHdr(disk, page, &hdr))
            return false;

        /* Increase free space */
        disk->free_bytes += disk->data_size;

        /* Check header FCS */
        if (hdr.fcs == computeFcs(&hdr))
        {
            ASSERT(hdr.fill <= disk->data_size);

            /* Page is valid and is owned by a file */
            filelen_table[hdr.inode]++;

            /* Keep trace of free space */
            disk->free_bytes -= hdr.fill;
            disk->free_page_start++;
        }
    }
    LOG_INFO("free_bytes:%ld, free_page_start:%d\n", (long)disk->free_bytes, disk->free_page_start);

    return true;
}

static bool fillPageArray(struct BattFsSuper *disk, pgoff_t *filelen_table)
{
    BattFsPageHeader hdr;
    pgcnt_t curr_free_page = disk->free_page_start;
    /* Fill page allocation array */
    for (pgcnt_t page = 0; page < disk->dev->blk_cnt; page++)
    {
        if (!readHdr(disk, page, &hdr))
            return false;

        /* Check header FCS */
        if (hdr.fcs == computeFcs(&hdr))
        {
            /* Compute array position */
            pgcnt_t array_pos = countPages(filelen_table, hdr.inode);
            array_pos += hdr.pgoff;


            /* Check if position is already used by another page of the same file */
            if (disk->page_array[array_pos] == PAGE_UNSET_SENTINEL)
                disk->page_array[array_pos] = page;
            else
            {
                BattFsPageHeader hdr_prv;

                if (!readHdr(disk, disk->page_array[array_pos], &hdr_prv))
                    return false;

                /* Check header FCS */
                ASSERT(hdr_prv.fcs == computeFcs(&hdr_prv));

                /* Only the very same page with a different seq number can be here */
                ASSERT(hdr.inode == hdr_prv.inode);
                ASSERT(hdr.pgoff == hdr_prv.pgoff);
                ASSERT(hdr.seq != hdr_prv.seq);

                pgcnt_t new_page, old_page;
                fill_t old_fill;

                /*
                 * Sequence number comparison: since
                 * seq is 40 bits wide, it wraps once
                 * every 1.1E12 times.
                 * The memory will not live enough to
                 * see a wraparound, so we can use a simple
                 * compare here.
                 */
                if (hdr.seq > hdr_prv.seq)
                {
                    /* Current header is newer than the previuos one */
                    old_page = disk->page_array[array_pos];
                    new_page = page;
                    old_fill = hdr_prv.fill;
                }
                else
                {
                    /* Previous header is newer than the current one */
                    old_page = page;
                    new_page = disk->page_array[array_pos];
                    old_fill = hdr.fill;
                }

                /* Set new page */
                disk->page_array[array_pos] = new_page;
                /* Add free space */
                disk->free_bytes += old_fill;
                /* Shift all array one position to the left, overwriting duplicate page */
                array_pos -= hdr.pgoff;
                array_pos += filelen_table[hdr.inode];
                movePages(disk, array_pos, -1);
                /* Move back all indexes */
                filelen_table[hdr.inode]--;
                disk->free_page_start--;
                curr_free_page--;
                /* Set old page as free */
                ASSERT(disk->page_array[curr_free_page] == PAGE_UNSET_SENTINEL);
                disk->page_array[curr_free_page++] = old_page;

            }
        }
        else
        {
            /* Invalid page, keep as free */
            ASSERT(disk->page_array[curr_free_page] == PAGE_UNSET_SENTINEL);
            //LOG_INFO("Page %d invalid, keeping as free\n", page);
            disk->page_array[curr_free_page++] = page;
        }
    }
    return true;
}


bool battfs_mount(struct BattFsSuper *disk, struct KBlock *dev, pgcnt_t *page_array, size_t array_size)
{
    pgoff_t filelen_table[BATTFS_MAX_FILES];

    ASSERT(dev);
    ASSERT(kblock_partialWrite(dev));
    disk->dev = dev;

    ASSERT(disk->dev->blk_size > BATTFS_HEADER_LEN);
    /* Fill page_size with the usable space */
    disk->data_size = disk->dev->blk_size - BATTFS_HEADER_LEN;
    ASSERT(disk->dev->blk_cnt);
    ASSERT(disk->dev->blk_cnt < PAGE_UNSET_SENTINEL - 1);
    ASSERT(page_array);
    disk->page_array = page_array;
    ASSERT(array_size >= disk->dev->blk_cnt * sizeof(pgcnt_t));

    memset(filelen_table, 0, BATTFS_MAX_FILES * sizeof(pgoff_t));

    disk->free_bytes = 0;
    disk->disk_size = (disk_size_t)disk->data_size * disk->dev->blk_cnt;

    /* Count pages per file */
    if (!countDiskFilePages(disk, filelen_table))
    {
        LOG_ERR("counting file pages\n");
        return false;
    }

    /* Once here, we have filelen_table filled with file lengths */

    /* Fill page array with sentinel */
    for (pgcnt_t page = 0; page < disk->dev->blk_cnt; page++)
        disk->page_array[page] = PAGE_UNSET_SENTINEL;

    /* Fill page allocation array using filelen_table */
    if (!fillPageArray(disk, filelen_table))
    {
        LOG_ERR("filling page array\n");
        return false;
    }
    #if LOG_LEVEL >= LOG_LVL_INFO
        dumpPageArray(disk);
    #endif
    #if CONFIG_BATTFS_SHUFFLE_FREE_PAGES
        SHUFFLE(&disk->page_array[disk->free_page_start], disk->dev->blk_cnt - disk->free_page_start);

        LOG_INFO("Page array after shuffle:\n");
        #if LOG_LEVEL >= LOG_LVL_INFO
            dumpPageArray(disk);
        #endif
    #endif
    /* Init list for opened files. */
    LIST_INIT(&disk->file_opened_list);
    return true;
}

bool battfs_fsck(struct BattFsSuper *disk)
{
    #define FSCHECK(cond) do { if(!(cond)) { LOG_ERR("\"" #cond "\"\n"); return false; } } while (0)

    FSCHECK(disk->free_page_start <= disk->dev->blk_cnt);
    FSCHECK(disk->data_size < disk->dev->blk_size);
    FSCHECK(disk->free_bytes <= disk->disk_size);

    disk_size_t free_bytes = 0;
    BattFsPageHeader hdr, prev_hdr;
    inode_t files = 0;
    pgcnt_t page_used = 0;

    bool start = true;

    /* Uneeded, the first time will be overwritten but useful to silence
     * the warning for uninitialized value */
    FSCHECK(readHdr(disk, 0, &prev_hdr));
    for (pgcnt_t page = 0; page < disk->dev->blk_cnt; page++)
    {
        FSCHECK(readHdr(disk, disk->page_array[page], &hdr));
        free_bytes += disk->data_size;

        if (page < disk->free_page_start)
        {
            FSCHECK(computeFcs(&hdr) == hdr.fcs);
            page_used++;
            free_bytes -= hdr.fill;
            if (hdr.inode != prev_hdr.inode || start)
            {
                if (LIKELY(!start))
                    FSCHECK(hdr.inode > prev_hdr.inode);
                else
                    start = false;

                FSCHECK(hdr.pgoff == 0);
                files++;
            }
            else
            {
                FSCHECK(hdr.fill != 0);
                FSCHECK(prev_hdr.fill == disk->data_size);
                FSCHECK(hdr.pgoff == prev_hdr.pgoff + 1);
            }
            prev_hdr = hdr;
        }
    }

    FSCHECK(page_used == disk->free_page_start);
    FSCHECK(free_bytes == disk->free_bytes);

    return true;
}

static int battfs_flush(struct KFile *fd)
{
    BattFs *fdb = BATTFS_CAST(fd);

    if (kblock_flush(fdb->disk->dev) == 0)
        return 0;
    else
    {
        fdb->errors |= BATTFS_DISK_FLUSHBUF_ERR;
        return EOF;
    }
}

static int battfs_fileclose(struct KFile *fd)
{
    BattFs *fdb = BATTFS_CAST(fd);

    if (battfs_flush(fd) == 0)
    {
        REMOVE(&fdb->link);
        return 0;
    }
    else
        return EOF;
}

#define NO_SPACE PAGE_UNSET_SENTINEL

static pgcnt_t allocateNewPage(struct BattFsSuper *disk, pgcnt_t new_pos, inode_t inode)
{
    if (SPACE_OVER(disk))
    {
        LOG_ERR("No disk space available!\n");
        return NO_SPACE;
    }

    LOG_INFO("Getting new page %d, pos %d\n", disk->page_array[disk->free_page_start], new_pos);
    pgcnt_t new_page = disk->page_array[disk->free_page_start++];
    memmove(&disk->page_array[new_pos + 1], &disk->page_array[new_pos], (disk->free_page_start - new_pos - 1) * sizeof(pgcnt_t));

    Node *n;
    /* Move following file start point one position ahead. */
    FOREACH_NODE(n, &disk->file_opened_list)
    {
        BattFs *file = containerof(n, BattFs, link);
        if (file->inode > inode)
        {
            LOG_INFO("Move file %d start pos\n", file->inode);
            file->start++;
        }
    }

    disk->page_array[new_pos] = new_page;
    return new_page;
}

static pgcnt_t renewPage(struct BattFsSuper *disk, pgcnt_t old_pos)
{
    if (SPACE_OVER(disk))
    {
        LOG_ERR("No disk space available!\n");
        return NO_SPACE;
    }

    /* Get a free page */
    pgcnt_t new_page = disk->page_array[disk->free_page_start];
    movePages(disk, disk->free_page_start + 1, -1);

    /* Insert previous page in free blocks list */
    LOG_INFO("Setting page %d as free\n", old_pos);
    disk->page_array[disk->dev->blk_cnt - 1] = old_pos;
    return new_page;
}

static size_t battfs_write(struct KFile *fd, const void *_buf, size_t size)
{
    BattFs *fdb = BATTFS_CAST(fd);
    BattFsSuper *disk = fdb->disk;
    const uint8_t *buf = (const uint8_t *)_buf;

    size_t total_write = 0;
    pgoff_t pg_offset;
    pgaddr_t addr_offset;
    pgaddr_t wr_len;
    BattFsPageHeader curr_hdr;
    pgcnt_t new_page;

    if (fd->seek_pos < 0)
    {
        fdb->errors |= BATTFS_NEGATIVE_SEEK_ERR;
        return total_write;
    }

    if (fd->seek_pos > fd->size)
    {
        if (!readHdr(disk, fdb->start[fdb->max_off], &curr_hdr))
        {
            fdb->errors |= BATTFS_DISK_READ_ERR;
            return total_write;
        }

        /*
         * Renew page only if is not in cache.
         * This avoids rewriting the same page continuously
         * if the user code keeps writing in the same portion
         * of the file.
         */
        if (kblock_buffered(disk->dev)
            && ((fdb->start[fdb->max_off] != kblock_cachedBlock(disk->dev)) || !kblock_cacheDirty(disk->dev)))
        {
            new_page = renewPage(disk, fdb->start[fdb->max_off]);
            if (new_page == NO_SPACE)
            {
                fdb->errors |= BATTFS_DISK_SPACEOVER_ERR;
                return total_write;
            }

            kblock_copy(disk->dev, fdb->start[fdb->max_off], new_page);
            fdb->start[fdb->max_off] = new_page;
        }
        else
            new_page = fdb->start[fdb->max_off];

        /* Fill unused space of first page with 0s */
        uint8_t dummy = 0;
        // TODO: write in blocks to speed up things
        pgaddr_t zero_bytes = MIN(fd->seek_pos - fd->size, (kfile_off_t)(disk->data_size - curr_hdr.fill));
        while (zero_bytes--)
        {
            if (kblock_write(disk->dev, new_page, &dummy, curr_hdr.fill, 1) != 1)
            {
                fdb->errors |= BATTFS_DISK_WRITE_ERR;
                return total_write;
            }
            curr_hdr.fill++;
            fd->size++;
            disk->free_bytes--;
        }
        curr_hdr.seq++;
        if (!writeHdr(disk, new_page, &curr_hdr))
        {
            fdb->errors |= BATTFS_DISK_WRITE_ERR;
            return total_write;
        }

        /* Allocate the missing pages first. */
        pgoff_t missing_pages = fd->seek_pos / disk->data_size - fdb->max_off;

        LOG_INFO("missing pages: %d\n", missing_pages);

        while (missing_pages--)
        {
            zero_bytes = MIN((kfile_off_t)disk->data_size, fd->seek_pos - fd->size);

            new_page = allocateNewPage(disk, (fdb->start - disk->page_array) + fdb->max_off + 1, fdb->inode);
            if (new_page == NO_SPACE)
            {
                fdb->errors |= BATTFS_DISK_SPACEOVER_ERR;
                return total_write;
            }


            // TODO: write in blocks to speed up things
            /* Fill page buffer with 0 to avoid filling unused pages with garbage */
            for (pgaddr_t off = 0; off < disk->data_size; off++)
            {
                if (kblock_write(disk->dev, new_page, &dummy, off, 1) != 1)
                {
                    fdb->errors |= BATTFS_DISK_WRITE_ERR;
                    return total_write;
                }
            }
            curr_hdr.inode = fdb->inode;
            curr_hdr.pgoff = ++fdb->max_off;
            curr_hdr.fill = zero_bytes;
            curr_hdr.seq = 0;

            if (!writeHdr(disk, new_page, &curr_hdr))
            {
                fdb->errors |= BATTFS_DISK_WRITE_ERR;
                return total_write;
            }

            /* Update size and free space left */
            fd->size += zero_bytes;
            disk->free_bytes -= zero_bytes;
        }
    }

    while (size)
    {
        pg_offset = fd->seek_pos / disk->data_size;
        addr_offset = fd->seek_pos % disk->data_size;
        wr_len = MIN(size, (size_t)(disk->data_size - addr_offset));

        /* Handle write outside EOF */
        if (pg_offset > fdb->max_off)
        {
            LOG_INFO("New page needed, pg_offset %d, pos %d\n", pg_offset, (int)((fdb->start - disk->page_array) + pg_offset));

            new_page = allocateNewPage(disk, (fdb->start - disk->page_array) + pg_offset, fdb->inode);
            if (new_page == NO_SPACE)
            {
                fdb->errors |= BATTFS_DISK_SPACEOVER_ERR;
                return total_write;
            }

            curr_hdr.inode = fdb->inode;
            curr_hdr.pgoff = pg_offset;
            curr_hdr.fill = 0;
            curr_hdr.seq = 0;
            fdb->max_off = pg_offset;
        }
        else
        {
            if (!readHdr(disk, fdb->start[pg_offset], &curr_hdr))
            {
                fdb->errors |= BATTFS_DISK_READ_ERR;
                return total_write;
            }

            /* Renew page only if is not in cache. */
            if (kblock_buffered(disk->dev)
                && ((fdb->start[fdb->max_off] != kblock_cachedBlock(disk->dev)) || !kblock_cacheDirty(disk->dev)))
            {
                new_page = renewPage(disk, fdb->start[pg_offset]);
                if (new_page == NO_SPACE)
                {
                    fdb->errors |= BATTFS_DISK_SPACEOVER_ERR;
                    return total_write;
                }

                LOG_INFO("Re-writing page %d to %d\n", fdb->start[pg_offset], new_page);
                if (kblock_copy(disk->dev, fdb->start[pg_offset], new_page) != 0)
                {
                    fdb->errors |= BATTFS_DISK_WRITE_ERR;
                    return total_write;
                }
                fdb->start[pg_offset] = new_page;
            }
            else
            {
                LOG_INFO("Using cached block %d\n", fdb->start[pg_offset]);
                new_page = fdb->start[pg_offset];
            }

            curr_hdr.seq++;
        }
        //LOG_INFO("writing to buffer for page %d, offset %d, size %d\n", disk->curr_page, addr_offset, wr_len);
        if (kblock_write(disk->dev, new_page, buf, addr_offset, wr_len) != wr_len)
        {
            fdb->errors |= BATTFS_DISK_WRITE_ERR;
            return total_write;
        }

        size -= wr_len;
        fd->seek_pos += wr_len;
        total_write += wr_len;
        buf += wr_len;
        fill_t fill_delta = MAX((int32_t)(addr_offset + wr_len) - curr_hdr.fill, (int32_t)0);
        disk->free_bytes -= fill_delta;
        fd->size += fill_delta;
        curr_hdr.fill += fill_delta;

        if (!writeHdr(disk, new_page, &curr_hdr))
        {
            fdb->errors |= BATTFS_DISK_WRITE_ERR;
            return total_write;
        }

        //LOG_INFO("free_bytes %d, seek_pos %d, size %d, curr_hdr.fill %d\n", disk->free_bytes, fd->seek_pos, fd->size, curr_hdr.fill);
    }
    return total_write;
}


static size_t battfs_read(struct KFile *fd, void *_buf, size_t size)
{
    BattFs *fdb = BATTFS_CAST(fd);
    BattFsSuper *disk = fdb->disk;
    uint8_t *buf = (uint8_t *)_buf;

    size_t total_read = 0;
    pgoff_t pg_offset;
    pgaddr_t addr_offset;
    pgaddr_t read_len;

    if (fd->seek_pos < 0)
    {
        fdb->errors |= BATTFS_NEGATIVE_SEEK_ERR;
        return total_read;
    }

    size = MIN((kfile_off_t)size, MAX(fd->size - fd->seek_pos, (kfile_off_t)0));

    while (size)
    {
        pg_offset = fd->seek_pos / disk->data_size;
        addr_offset = fd->seek_pos % disk->data_size;
        read_len = MIN(size, (size_t)(disk->data_size - addr_offset));

        //LOG_INFO("reading from page %d, offset %d, size %d\n", fdb->start[pg_offset], addr_offset, read_len);
        /* Read from disk */
        if (kblock_read(disk->dev, fdb->start[pg_offset], buf, addr_offset, read_len) != read_len)
        {
            fdb->errors |= BATTFS_DISK_READ_ERR;
            return total_read;
        }

        #ifdef _DEBUG
            BattFsPageHeader hdr;
            readHdr(disk, fdb->start[pg_offset], &hdr);
            ASSERT(hdr.inode == fdb->inode);
        #endif

        size -= read_len;
        fd->seek_pos += read_len;
        total_read += read_len;
        buf += read_len;
    }
    return total_read;
}


static bool findFile(BattFsSuper *disk, inode_t inode, pgcnt_t *last)
{
    BattFsPageHeader hdr;
    pgcnt_t first = 0, page;
    *last = disk->free_page_start;
    fcs_t fcs;

    while (first < *last)
    {
        page = (first + *last) / 2;
        LOG_INFO("first %d, last %d, page %d\n", first, *last, page);
        if (!readHdr(disk, disk->page_array[page], &hdr))
            return false;
        LOG_INFO("inode read: %d\n", hdr.inode);
        fcs = computeFcs(&hdr);
        if (hdr.fcs == fcs && hdr.inode == inode)
        {
            *last = page - hdr.pgoff;
            LOG_INFO("Found: %d\n", *last);
            return true;
        }
        else if (hdr.fcs == fcs && hdr.inode < inode)
            first = page + 1;
        else
            *last = page;
    }
    LOG_INFO("Not found: last %d\n", *last);
    return false;
}

bool battfs_fileExists(BattFsSuper *disk, inode_t inode)
{
    pgcnt_t dummy;
    return findFile(disk, inode, &dummy);
}

static file_size_t countFileSize(BattFsSuper *disk, pgcnt_t *start, inode_t inode)
{
    file_size_t size = 0;
    BattFsPageHeader hdr;

    while (start < &disk->page_array[disk->free_page_start])
    {
        if (!readHdr(disk, *start++, &hdr))
            return EOF;
        if (hdr.fcs == computeFcs(&hdr) && hdr.inode == inode)
            size += hdr.fill;
        else
            break;
    }
    return size;
}

static int battfs_error(struct KFile *fd)
{
    BattFs *fdb = BATTFS_CAST(fd);
    return fdb->errors;
}


static void battfs_clearerr(struct KFile *fd)
{
    BattFs *fdb = BATTFS_CAST(fd);
    fdb->errors = 0;
}

bool battfs_fileopen(BattFsSuper *disk, BattFs *fd, inode_t inode, filemode_t mode)
{
    Node *n;

    memset(fd, 0, sizeof(*fd));

    /* Search file start point in disk page array */
    pgcnt_t start_pos;
    if (!findFile(disk, inode, &start_pos))
    {
        LOG_INFO("file %d not found\n", inode);
        if (!(mode & BATTFS_CREATE))
        {
            fd->errors |= BATTFS_FILE_NOT_FOUND_ERR;
            return false;
        }
        /* Create the file */
        BattFsPageHeader hdr;

        if (allocateNewPage(disk, start_pos, inode) == NO_SPACE)
        {
            fd->errors |= BATTFS_DISK_SPACEOVER_ERR;
            return false;
        }

        hdr.inode = inode;
        hdr.pgoff = 0;
        hdr.fill = 0;
        hdr.seq = 0;
        if (!writeHdr(disk, disk->page_array[start_pos], &hdr))
        {
            fd->errors |= BATTFS_DISK_WRITE_ERR;
            return false;
        }
    }
    fd->start = &disk->page_array[start_pos];
    LOG_INFO("Start pos %d\n", start_pos);

    /* Fill file size */
    if ((fd->fd.size = countFileSize(disk, fd->start, inode)) == EOF)
    {
        fd->errors |= BATTFS_DISK_READ_ERR;
        return false;
    }
    fd->max_off = fd->fd.size / disk->data_size;

    /* Reset seek position */
    fd->fd.seek_pos = 0;

    /* Insert file handle in list, ordered by inode, ascending. */
    FOREACH_NODE(n, &disk->file_opened_list)
    {
        BattFs *file = containerof(n, BattFs, link);
        if (file->inode >= inode)
            break;
    }
    INSERT_BEFORE(&fd->link, n);

    /* Fill in data */
    fd->inode = inode;
    fd->mode = mode;
    fd->disk = disk;

    fd->fd.close = battfs_fileclose;
    fd->fd.flush = battfs_flush;
    fd->fd.read = battfs_read;
    fd->fd.reopen = kfile_genericReopen;
    fd->fd.seek = kfile_genericSeek;
    fd->fd.write = battfs_write;

    fd->fd.error = battfs_error;
    fd->fd.clearerr = battfs_clearerr;

    DB(fd->fd._type = KFT_BATTFS);

    return true;
}


bool battfs_umount(struct BattFsSuper *disk)
{
    Node *n;
    int res = 0;

    /* Close all open files */
    FOREACH_NODE(n, &disk->file_opened_list)
    {
        BattFs *file = containerof(n, BattFs, link);
        res += battfs_fileclose(&file->fd);
    }

    /* Close disk */
    return (kblock_flush(disk->dev) == 0) && (kblock_close(disk->dev) == 0) && (res == 0);
}

#if UNIT_TEST

void battfs_writeTestBlock(KBlock *dev, pgcnt_t page, inode_t inode, seq_t seq, fill_t fill, pgoff_t pgoff)
{
    uint8_t buf[BATTFS_HEADER_LEN];
    battfs_eraseBlock(dev, page);

    BattFsPageHeader hdr;
    hdr.inode = inode;
    hdr.fill = fill;
    hdr.pgoff = pgoff;
    hdr.seq = seq;
    hdr.fcs = computeFcs(&hdr);

    battfs_to_disk(&hdr, buf);

    ASSERT(kblock_write(dev, page, buf, dev->blk_size - BATTFS_HEADER_LEN, BATTFS_HEADER_LEN) == BATTFS_HEADER_LEN);
    ASSERT(kblock_flush(dev) == 0);
}

void battfs_eraseBlock(KBlock *dev, pgcnt_t page)
{
    /* Reset page to all 0xff */
    uint8_t buf[dev->blk_size];
    memset(buf, 0xFF, dev->blk_size);
    ASSERT(kblock_write(dev, page, buf, 0, dev->blk_size) == dev->blk_size);
    ASSERT(kblock_flush(dev) == 0);
}

#endif