+++ /dev/null
-/**
- * \file
- * <!--
- * This file is part of BeRTOS.
- *
- * Bertos 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.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * As a special exception, you may use this file as part of a free software
- * library without restriction. Specifically, if other files instantiate
- * templates or use macros or inline functions from this file, or you compile
- * this file and link it with other files to produce an executable, this
- * file does not by itself cause the resulting executable to be covered by
- * the GNU General Public License. This exception does not however
- * invalidate any other reasons why the executable file might be covered by
- * the GNU General Public License.
- *
- * Copyright 2007 Develer S.r.l. (http://www.develer.com/)
- *
- * -->
- *
- * \version $Id:$
- *
- * \author Francesco Sacchi <batt@develer.com>
- *
- * \brief BattFS: a filesystem for embedded platforms (implementation).
- */
-
-#include "battfs.h"
-
-#include <cfg/debug.h>
-#include <cfg/macros.h> /* MIN, MAX */
-#include <mware/byteorder.h> /* cpu_to_xx */
-
-
-#include <string.h> /* memset, memmove */
-
-
-/**
- * Convert from memory representation to disk structure.
- * \note filesystem is in little-endian format.
- */
-INLINE void battfs_to_disk(struct BattFsPageHeader *hdr, uint8_t *buf)
-{
- STATIC_ASSERT(BATTFS_HEADER_LEN == 13);
- buf[0] = hdr->inode;
-
- buf[1] = hdr->seq;
-
- buf[2] = hdr->fill;
- buf[3] = hdr->fill >> 8;
-
- buf[4] = hdr->pgoff;
- buf[5] = hdr->pgoff >> 8;
-
- /*
- * Mark is at least 1 bit longer than page address.
- * Needed to take care of wraparonds.
- */
- buf[6] = hdr->mark;
- buf[7] = hdr->mark >> 8;
- buf[8] = hdr->mark >> 16;
-
- /*
- * This field must be the before the last one!
- */
- buf[9] = hdr->fcs_free;
- buf[10] = hdr->fcs_free >> 8;
-
- /*
- * 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[11] = hdr->fcs;
- buf[12] = hdr->fcs >> 8;
-}
-
-/**
- * Convert from disk structure to memory representation.
- * \note filesystem is in little-endian format.
- */
-INLINE void disk_to_battfs(uint8_t *buf, struct BattFsPageHeader *hdr)
-{
- STATIC_ASSERT(BATTFS_HEADER_LEN == 13);
- hdr->inode = buf[0];
- hdr->seq = buf[1];
- hdr->fill = buf[3] << 8 | buf[2];
- hdr->pgoff = buf[5] << 8 | buf[4];
- hdr->mark = (mark_t)buf[8] << 16 | buf[7] << 8 | buf[6];
- hdr->fcs_free = buf[10] << 8 | buf[9];
- hdr->fcs = buf[12] << 8 | buf[11];
-}
-
-/**
- * Compute the fcs of the header.
- */
-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;
-}
-
-/**
- * Compute the fcs of the header marked as free.
- */
-static fcs_t computeFcsFree(struct BattFsPageHeader *hdr)
-{
- uint8_t buf[BATTFS_HEADER_LEN];
- fcs_t cks;
-
- battfs_to_disk(hdr, buf);
- rotating_init(&cks);
- /* fcs_free is just before fcs of whole header */
- rotating_update(buf,BATTFS_HEADER_LEN - 2 * sizeof(fcs_t), &cks);
- return cks;
-}
-
-
-/**
- * Read header of page \a page.
- * \return true on success, false otherwise.
- * \note \a hdr is dirtyed even on errors.
- */
-static bool battfs_readHeader(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 (disk->read(disk, page, disk->page_size - BATTFS_HEADER_LEN - 1, buf, BATTFS_HEADER_LEN)
- != BATTFS_HEADER_LEN)
- {
- TRACEMSG("Error: page[%d]\n", page);
- return false;
- }
-
- /* Fill header */
- disk_to_battfs(buf, hdr);
-
- return true;
-}
-
-/**
- * Count the number of pages from
- * inode 0 to \a inode in \a filelen_table.
- */
-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;
-}
-
-/**
- * Move all pages in page allocation array from \a src to \a src + \a offset.
- * The number of pages moved is page_count - MAX(dst, src).
- */
-static void movePages(struct BattFsSuper *disk, pgcnt_t src, int offset)
-{
- pgcnt_t dst = src + offset;
- memmove(&disk->page_array[dst], &disk->page_array[src], disk->page_count - MAX(dst, src) * sizeof(pgcnt_t));
-
- if (offset < 0)
- {
- /* Fill empty space in array with sentinel */
- for (pgcnt_t page = disk->page_count + offset; page < disk->page_count; page++)
- disk->page_array[page] = PAGE_UNSET_SENTINEL;
- }
-}
-
-/**
- * Insert \a page into page allocation array of \a disk, using \a filelen_table and
- * \a free_number to compute position.
- */
-static void insertFreePage(struct BattFsSuper *disk, pgoff_t *filelen_table, mark_t mark, pgcnt_t page)
-{
- ASSERT(mark >= disk->free_start);
- ASSERT(mark < disk->free_next);
-
- pgcnt_t free_pos = countPages(filelen_table, BATTFS_MAX_FILES - 1);
- free_pos += mark - disk->free_start;
- TRACEMSG("mark:%d, page:%d, free_start:%d, free_next:%d, free_pos:%d\n",
- mark, page, disk->free_start, disk->free_next, free_pos);
-
- ASSERT(disk->page_array[free_pos] == PAGE_UNSET_SENTINEL);
- disk->page_array[free_pos] = page;
-}
-
-/**
- * Mark \a page of \a disk as free.
- * \note free_next of \a disk is used as \a page free marker
- * and is increased by 1.
- */
-static bool battfs_markFree(struct BattFsSuper *disk, struct BattFsPageHeader *hdr, pgcnt_t page)
-{
- uint8_t buf[BATTFS_HEADER_LEN];
-
- hdr->mark = disk->free_next;
- hdr->fcs_free = computeFcsFree(hdr);
- battfs_to_disk(hdr, buf);
-
- if (!disk->write(disk, page, disk->page_size - BATTFS_HEADER_LEN - 1, buf, BATTFS_HEADER_LEN))
- {
- TRACEMSG("error marking page [%d]\n", page);
- return false;
- }
- else
- {
- disk->free_next++;
- return true;
- }
-}
-
-
-/**
- * Initialize and mount disk described by
- * \a d.
- * \return false on errors, true otherwise.
- */
-bool battfs_init(struct BattFsSuper *disk)
-{
- BattFsPageHeader hdr;
- pgoff_t filelen_table[BATTFS_MAX_FILES];
- mark_t minl, maxl, minh, maxh;
-
- /* Sanity check */
- ASSERT(disk->open);
-
- /* Init disk device */
- if (!disk->open(disk))
- {
- TRACEMSG("open error\n");
- return false;
- }
-
- /* Disk open must set all of these */
- ASSERT(disk->read);
- ASSERT(disk->write);
- ASSERT(disk->erase);
- ASSERT(disk->close);
- ASSERT(disk->page_size);
- ASSERT(disk->page_count);
- ASSERT(disk->page_count < PAGE_UNSET_SENTINEL - 1);
- ASSERT(disk->page_array);
-
- memset(filelen_table, 0, BATTFS_MAX_FILES * sizeof(pgoff_t));
-
- /* Initialize min and max counters to keep trace od free blocks */
- minl = MAX_PAGE_ADDR;
- maxl = 0;
- minh = MAX_PAGE_ADDR | MARK_HALF_SIZE;
- maxh = 0 | MARK_HALF_SIZE;
-
- disk->free_bytes = 0;
- disk->disk_size = (disk_size_t)(disk->page_size - BATTFS_HEADER_LEN) * disk->page_count;
-
- /* Count the number of disk page per file */
- for (pgcnt_t page = 0; page < disk->page_count; page++)
- {
- if (!battfs_readHeader(disk, page, &hdr))
- return false;
-
- /* Check header FCS */
- if (hdr.fcs == computeFcs(&hdr))
- {
- ASSERT(hdr.mark == MARK_PAGE_VALID);
- ASSERT(hdr.fcs_free == FCS_FREE_VALID);
- ASSERT(hdr.fill <= disk->page_size - BATTFS_HEADER_LEN);
-
- /* Page is valid and is owned by a file */
- filelen_table[hdr.inode]++;
-
- /* Keep trace of free space */
- disk->free_bytes += disk->page_size - BATTFS_HEADER_LEN - hdr.fill;
- }
- else
- {
- /* Increase free space */
- disk->free_bytes += disk->page_size - BATTFS_HEADER_LEN;
-
- /* Check if page is marked free */
- if (hdr.fcs_free == computeFcsFree(&hdr))
- {
- /*
- * This page is a valid and marked free page.
- * Update min and max free page markers.
- */
- if (hdr.mark < MARK_HALF_SIZE)
- {
- minl = MIN(minl, hdr.mark);
- maxl = MAX(maxl, hdr.mark);
- }
- else
- {
- minh = MIN(minh, hdr.mark);
- maxl = MAX(maxl, hdr.mark);
- }
- }
- else
- TRACEMSG("page [%d] invalid, keeping as free\n", page);
- }
- }
-
- /* Once here, we have filelen_table filled with file lengths */
-
- /* Fill page array with sentinel */
- for (pgcnt_t page = 0; page < disk->page_count; page++)
- disk->page_array[page] = PAGE_UNSET_SENTINEL;
-
- /* Determine free_start & free_next */
- if (maxl >= minl)
- {
- if (maxh >= minh)
- {
- if (maxl == minh - 1)
- {
- disk->free_start = minl;
- disk->free_next = maxh;
- }
- else
- {
- ASSERT(minl == 0);
- ASSERT(maxh == (MAX_PAGE_ADDR | MARK_HALF_SIZE));
-
- disk->free_start = minh;
- disk->free_next = maxl;
- }
- }
- else
- {
- disk->free_start = minl;
- disk->free_next = maxl;
- }
- }
- else if (maxh >= minh)
- {
- disk->free_start = minh;
- disk->free_next = maxh;
- }
- else
- {
- TRACEMSG("No valid marked free block found\n");
- disk->free_start = 0;
- disk->free_next = -1;
- }
-
- /* free_next should contain the first usable address */
- disk->free_next++;
-
- TRACEMSG("Free markers:\n minl %u\n maxl %u\n minh %u\n maxh %u\n free_start %u\n free_next %u\n",
- minl, maxl, minh, maxh, disk->free_start, disk->free_next);
-
-
- /* Fill page allocation array */
- for (pgcnt_t page = 0; page < disk->page_count; page++)
- {
- if (!battfs_readHeader(disk, page, &hdr))
- return false;
-
- /* Check header FCS */
- if (hdr.fcs == computeFcs(&hdr))
- {
- /* Page is valid and is owned by a file */
- ASSERT(hdr.mark == MARK_PAGE_VALID);
- ASSERT(hdr.fcs_free == FCS_FREE_VALID);
-
- /* 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 (LIKELY(disk->page_array[array_pos] == PAGE_UNSET_SENTINEL))
- disk->page_array[array_pos] = page;
- else
- {
- BattFsPageHeader hdr_old;
-
- if (!battfs_readHeader(disk, disk->page_array[array_pos], &hdr_old))
- return false;
-
- /* Check header FCS */
- ASSERT(hdr_old.fcs == computeFcs(&hdr_old));
-
- /* Only the very same page with a different seq number can be here */
- ASSERT(hdr.inode == hdr_old.inode);
- ASSERT(hdr.pgoff == hdr_old.pgoff);
- ASSERT(hdr.mark == hdr_old.mark);
- ASSERT(hdr.fcs_free == hdr_old.fcs_free);
- ASSERT(hdr.seq != hdr_old.seq);
-
- pgcnt_t new_page, old_page;
- fill_t old_fill;
-
- /* Fancy check to handle seq wraparound */
- #define HALF_SEQ (1 << ((sizeof(seq_t) * CPU_BITS_PER_CHAR) - 1))
- if ((hdr.seq - hdr_old.seq) < HALF_SEQ)
- {
- /* Current header is newer than the previuos one */
- old_page = disk->page_array[array_pos];
- new_page = page;
- old_fill = hdr_old.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);
-
- /* Decrease file page count */
- filelen_table[hdr.inode]--;
-
- /* Add old page to free pages pool */
- if (!battfs_markFree(disk, &hdr, old_page))
- return false;
-
- insertFreePage(disk, filelen_table, hdr.mark, old_page);
- }
- }
- else
- {
- /* Check if page is free */
- if (hdr.fcs_free != computeFcsFree(&hdr))
- /* Page is not a valid marked page, insert at the end of list */
- hdr.mark = disk->free_next++;
-
- insertFreePage(disk, filelen_table, hdr.mark, page);
- }
- }
-
- #warning Test me!
- return true;
-}
-
-
projects / bertos.git / blobdiff