+ /* Fill page array with sentinel */
+ for (pgcnt_t page = 0; page < disk->page_count; page++)
+ disk->page_array[page] = PAGE_UNSET_SENTINEL;
+
+ /* 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 */
+ rotating_init(&cks);
+ rotating_update(&hdr, sizeof(BattFsPageHeader) - sizeof(rotating_t), &cks);
+ if (cks == hdr.fcs)
+ {
+ /* Page is valid and is owned by a file */
+ ASSERT(hdr.mark == MARK_PAGE_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 (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;
+
+ #ifdef _DEBUG
+ /* Check header FCS */
+ rotating_t cks_old;
+ rotating_init(&cks_old);
+ rotating_update(&hdr_old, sizeof(BattFsPageHeader) - sizeof(rotating_t), &cks_old);
+ ASSERT(cks_old == hdr_old.fcs);
+ #endif
+
+ /* 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.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)
+ {
+ /* Actual 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, old_page))
+ return false;
+
+ insertFreePage(disk, filelen_table, disk->max_free, old_page);
+ }
+ }
+ else
+ {
+ /* Check if setting mark to MARK_PAGE_VALID makes fcs correct */
+ mark_t mark = hdr.mark;
+ hdr.mark = MARK_PAGE_VALID;
+ rotating_init(&cks);
+ rotating_update(&hdr, sizeof(BattFsPageHeader) - sizeof(rotating_t), &cks);
+ if (cks != hdr.fcs)
+ /* Page is not a valid marked page, insert at the end of list */
+ mark = ++disk->max_free;
+
+ insertFreePage(disk, filelen_table, mark, page);
+ }
+ }
+
+ #warning Test me!