Got the OS to boot from new disk image

- Pretty much rewrote stage1.asm
- Changed some addresses in stage2.asm and in memory/adresses.h
- Changed stage3.c to read root INode and it's dirEntries to find kernel.bin and term16n.fnt
- Made a fake ls command in kernel.c, just so it prints something
- Fixed makedisk.c to make the disk image properly
- Changed Makefile to compile makedisk.c and then run makedisk
- Added makedisk executable to .gitignore

.gitignore

@@ -1,2 +1,3 @@
 build
 kern.iso
+makedisk

Makefile

@@ -14,24 +14,11 @@ FONTS = testfont term16n
 .PHONY: os clean run
 
 # Main compilation target
-os: $(BUILD) filesystem
+os: $(BUILD) bootloader kernel $(C_FILES) $(FONTS)
+	@cc ./makedisk.c -o ./makedisk
+	@./makedisk # TODO: List of files
 	@echo "\nDone!\n"
 
-# Filesystem
-filesystem: bootloader kernel $(C_FILES) $(FONTS)
-	@echo "Building filesystem..."
-	@$(AS) -fbin -o $(BUILD)/filetable.bin $(SRC)/filetable.asm
-	@dd if=/dev/zero of=kern.iso bs=512 count=2880 status=none
-# TODO: Make this not so manual
-	@dd if=$(BUILD)/boot.bin      of=kern.iso bs=512 seek=0  conv=notrunc status=none
-	@dd if=$(BUILD)/filetable.bin of=kern.iso bs=512 seek=15 conv=notrunc status=none
-	@dd if=$(BUILD)/kernel.bin    of=kern.iso bs=512 seek=16 conv=notrunc status=none
-	@dd if=$(BUILD)/term16n.fnt   of=kern.iso bs=512 seek=56 conv=notrunc status=none
-	@dd if=$(BUILD)/testfont.fnt  of=kern.iso bs=512 seek=60 conv=notrunc status=none
-	@dd if=$(SRC)/fs/test.txt     of=kern.iso bs=512 seek=64 conv=notrunc status=none
-	@dd if=$(BUILD)/calc.bin      of=kern.iso bs=512 seek=65 conv=notrunc status=none
-	@dd if=$(BUILD)/editor.bin    of=kern.iso bs=512 seek=71 conv=notrunc status=none
-
 $(BUILD):
 	@[ -d $(BUILD) ] || mkdir $(BUILD)
 	@rm -rf $(BUILD)/*
@@ -55,12 +42,14 @@ kernel: $(SRC)/kernel.c
 	@$(LD) -T$(SRC)/kernel.ld -z notext --oformat binary -o $(BUILD)/kernel.bin $(BUILD)/kernel.o
 	@rm $(BUILD)/kernel.o
 
+# This target compiles *.c (except kernel.c)
 $(C_FILES):
 	@echo "Compiling $(SRC)/$@.c..."
 	@$(CC) $(CFLAGS) -o $(BUILD)/$@.o -c $(SRC)/$@.c 
 	@$(LD) -T$(SRC)/$@.ld -z notext --oformat binary -o $(BUILD)/$@.bin $(BUILD)/$@.o
 	@rm $(BUILD)/$@.o
 
+# This target builds all fonts inside src/fonts
 $(FONTS):
 	@echo "Assembling $(SRC)/fonts/$@.asm..."
 	@$(AS) -fbin -o $(BUILD)/$@.fnt $(SRC)/fonts/$@.asm

include/memory/addresses.h

@@ -2,25 +2,28 @@
 #define ADDRESSES_H
 
 /*
- * Memory layout of addresses 0x0000 - 0xA000
+ * Memory layout of addresses 0x0000 - 0x12000
  * 0x0000-0x0fff - Probably shouldn't mess with this? idk it feels wrong
  * 0x1000-0x17ff - Free
  * 0x1800-0x1fff - Global Variables
  * 0x2000-0x2fff - Larger structs
- * 0x3000-0x3fff - Filesystem area
+ * 0x3000-0x3fff - Free
  * 0x4000-0x4fff - Font area
- * 0x6000-0x84ff - Free
+ * 0x6000-0x6fff - VBE info area
- * 0x8500-0x8fff - SMAP Area
+ * 0x7000-0x7bff - SMAP Area
- * 0x9000-0x9fff - VBE info area
+ * 0x7c00-0x8bff - Bootblock
+ * 0x8c00-0x9bff - Superblock (i think)
+ * 0x9c00-0xafff - Free
+ * 0xb000-0xbfff - Bootloader first INode
  */
 
-// Global Variables
+// Global Variables 0x1800-0x1fff
 #define SLEEP_TIMER             0x1800
 #define CURRENT_PAGE_DIR_ADDR   0x1804
 #define PHYS_MEM_MAX_BLOCKS     0x1808
 #define PHYS_MEM_USED_BLOCKS    0x180C
 
-// Some structs
+// Some structs 0x2000-0x2fff
 #define TERMINAL_INFO_LOC       0x2000
 #define KEYBOARD_STATE_LOC      0x2100
 #define DATETIME_LOC            0x2200
@@ -33,12 +36,22 @@
 #define FONT_WIDTH              (FONT_LOC)
 #define FONT_HEIGHT             (FONT_LOC + 1)
 
-// Smap Area 0x8500 - 0x8fff
+// VBE Info Area 0x6000 - 0x6fff
-#define SMAP_ENTRY_COUNT        0x8500
+#define MODE_INFO_BLOCK_LOC     0x6000 // 512 Bytes
-#define SMAP_ENTRIES            0x8504
 
-// VBE Info Area 0x9000 - 0x9fff
+// Smap Area 0x7000 - 0x7bff
-#define MODE_INFO_BLOCK_LOC     0x9000 // 512 Bytes
+#define SMAP_ENTRY_COUNT        0x7000
+#define SMAP_ENTRIES            0x7004
+
+// Bootblock 0x7c00-0x9bff
+#define BOOTBLOCK_LOC           0x7c00
+
+// Superblock 0x9c00-0xabff
+#define SUPERBLOCK_LOC          0x8c00
+
+// First INode from bootloader
+#define BOOT_FIRST_INODE_LOC    0xb000
+#define SCRATCH_BLOCK_LOC       0xc000
 
 // Other addresses
 #define KERNEL_LOC              0x100000

makedisk.c

@@ -83,10 +83,9 @@ int main(int argc, char** argv) {
     printf("Free blocks: %d (%d Bytes)\n", bytesToBlocks(diskSize) - writtenBlocks, diskSize - writtenBlocks * FS_BLOCK_SIZE);
 
     // Pad out to the whole disk size
-    /*
     for (uint32_t i = 0; i < bytesToBlocks(diskSize) - writtenBlocks; i++) {
         assert(fwrite(nullBlock, FS_BLOCK_SIZE, 1, imagePtr) == 1);
-    } */
+    }
     
     // Cleanup
     for (uint32_t i = 0; i < fileCount; i++) {
@@ -120,9 +119,9 @@ void writeSuperblock() {
     superblock.inodeCount = fileCount;  // 2 reserved INodes (0 - Invalid, 1 - Root)
     superblock.firstInodeBitmapBlock = 2;   // Block 0 - Boot, Block 1 - Superblock
     superblock.inodeBitmapBlockCount = superblock.inodeCount / (FS_BLOCK_SIZE * 8) + ((superblock.inodeCount % (FS_BLOCK_SIZE * 8) > 0) ? 1 : 0);
-    superblock.firstDataBitmapBlock = superblock.firstInodeBlock + superblock.inodeBitmapBlockCount;
+    superblock.firstDataBitmapBlock = superblock.firstInodeBitmapBlock + superblock.inodeBitmapBlockCount;
     superblock.inodeBlockCount = bytesToBlocks(superblock.inodeCount * sizeof(inode_t));
-    
+
     dataBlocks = bytesToBlocks(diskSize);
     dataBitCount = (dataBlocks - superblock.firstDataBitmapBlock - superblock.inodeBlockCount);
 
@@ -195,13 +194,16 @@ void writeINodeBlocks() {
         .id = 1,
         .filetype = FILETYPE_DIR,
         .sizeBytes = sizeof(dirEntry_t) * fileCount,
-        .sizeSectors = bytesToSectors(inode.sizeBytes),
+        // .sizeSectors = bytesToSectors(inode.sizeBytes), Set below
         .timestamp = defaultTimestamp,
         .extent[0] = (extent_t) {
             .firstBlock = superblock.firstDataBlock,
-            .length = bytesToBlocks(inode.sizeBytes),
+            // .length = bytesToBlocks(inode.sizeBytes), Set below
         },
     };
+
+    inode.sizeSectors = bytesToSectors(inode.sizeBytes);
+    inode.extent[0].length = bytesToBlocks(inode.sizeBytes);
         
     assert(fwrite(&inode, sizeof(inode), 1, imagePtr) == 1);
 
@@ -216,8 +218,9 @@ void writeINodeBlocks() {
         inode.timestamp = defaultTimestamp;
         inode.extent[0] = (extent_t) {
             .firstBlock = block,
-            .length = bytesToBlocks(inode.sizeBytes),
+            // .length = bytesToBlocks(inode.sizeBytes),
         };
+        inode.extent[0].length = bytesToBlocks(inode.sizeBytes);
 
         assert(fwrite(&inode, sizeof(inode), 1, imagePtr) == 1);
         

src/kernel.c

@@ -25,10 +25,10 @@
 #include <color.h>
 #include <fs/fs.h>
 
-#define PROMPT "#> "
+#define PROMPT "/ #> "
 
 // Function declarations
-void printFiletable(char* ft);
+void listFiles();
 void printPhysicalMemmap();
 
 __attribute__ ((section("entry")))
@@ -71,13 +71,11 @@ void main() {
     mallocVirtualAddr = kernelMallocVirtualAddr;
     mallocPhysicalAddr = kernelMallocPhysicalAddr;
     mallocPages = kernelMallocPages;
- 
+
-    // Screen setup
-    loadFont("term16n.fnt");
     terminal->fg = FG_COLOR;
     terminal->bg = BG_COLOR;
     clear();
-    printf("kern.\n\n");
+    print("kern.\n\n");
 
     // Run Interactive Shell Program
     // TODO: Make it in another file
@@ -174,14 +172,14 @@ void main() {
             printf(" exit       | Exits shell\n");
             printf(" gfx        | Does a graphics test\n");
             printf(" help       | Prints this message\n");
-            printf(" ls         | Lists all available files\n");
+            printf(" ls         | Lists files in current directory\n");
             printf(" memmap     | Prints the memory map and info\n");
             printf(" reboot     | Reboots the system\n");
             printf(" sleep      | Sleeps for input number of seconds\n");
             printf(" soundtest  | Plays a tune :)\n");
             printf(" test       | Performs tests\n");
         } else if (strcmp(argv[0], "ls") == 0) {
-            printFiletable(filetable);
+            listFiles();
         } else if (strcmp(argv[0], "memmap") == 0) {
             printPhysicalMemmap();
         } else if (strcmp(argv[0], "reboot") == 0) {
@@ -269,8 +267,6 @@ void main() {
                 mallocVirtualAddr = kernelMallocVirtualAddr;
                 mallocPhysicalAddr = kernelMallocPhysicalAddr;
                 mallocPages = kernelMallocPages;
-            } else if (strcmp(file->filetype, "tab") == 0) {
-                printFiletable(entryPoint);
             } else if (strcmp(file->filetype, "fnt") == 0) {
                 printf("Loading %s...\n", file->filename);
                 memcpy(entryPoint, (char*)FONT_LOC, file->length * 512);
@@ -299,40 +295,17 @@ void main() {
     while (1); // Just hang
 }
 
-void printFiletable(char* ft) {
+void listFiles() {
-    while (*ft != '\0') {
+    // TODO: Make this real
-        char filename[15] = { 0 };
+    printf("Total 8\n");
-        uint8_t offset = 0;
+    printf(".               [dir]\n");
-        for (uint8_t i = 0; i < 14; i++) {
+    printf("..              [dir]\n");
-            if (i == 9) {
+    printf("stage3.bin      2868B\n");
-                filename[offset++] = '.';
+    printf("kernel.bin      13536B\n");
-                continue;
+    printf("testfont.fnt    2048B\n");
-            }
+    printf("term16n.fnt     2048B\n");
-            if (*ft != '\0') { filename[offset++] = *ft; }
+    printf("calc.bin        1724B\n");
-            ft++;
+    printf("editor.bin      1280B\n");
-        }
-        ft++; // RESERVED
-
-        uint8_t sector = *ft++;
-        uint8_t size = *ft++;
-
-        // TODO: Use printf() here for padding
-        if (sector < 10) putc('0');
-        if (sector == 0) putc('0');
-        else printf("%d", sector);
-        printf(": %s", filename);
-
-        for (uint8_t i = 14 - strlen(filename); i > 0; i--) {
-            printf(" ");
-        }
-
-        printf(" | ");
-        if (size >> 1) {
-            printf("%d%skB\n", size >> 1, (size & 0x01) ? ".5" : "");
-        } else {
-            printf("%dB\n", size * 512);
-        }
-    }
 }
 
 void printPhysicalMemmap() {

src/stage1.asm

@@ -1,97 +1,167 @@
 [bits 16]
 [org 0x7c00]
-[global start]
 
-%define VIDMEM 0xb800
+%define SUPERBLOCK 0x8c00
-%define FILETAB_LOC 0x7000
+%define FIRST_INODE_BLOCK (SUPERBLOCK) + 12
+%define STAGE3_INODE 0xb000 + 128
+%define EXTENT0 (STAGE3_INODE) + 21      ; Offset of extent[0] in inode_t
 
 start:
-    mov [driveNum], dl   ; Store the drive number
     xor ax, ax
     mov es, ax
-    mov ds, ax
+    mov ds, ax     
+
+    mov byte [driveNum], dl
 
     ; Clear screen
     mov ax, 0x03
     int 0x10
 
-    ; Reset disk
+    ;; Read in the boot block and the superblock to memory for 2nd stage bootloader
-    mov ah, 0x0
+    mov al, 15          ; 8 - 1 for boot block - bootsector & 8 for super block
-    mov dl, [driveNum]
+    mov bl, al
-    int 0x13
+    dec bl              ; Number of sectors - 1
+    mov di, 0x7E00      ; Destination 0x7c00-0x8c00 = boot block, 0x8c00-0x9c00 = superblock
 
-.read:
+    mov dx, 0x1F6       ; flags
-    ; Location
+    mov al, 0xE0        ; 0b0111 0000, bits: 0-3 = LBA bits 24-27, 4 = drive, 5 = always set, 6 = set for LBA, 7 = always set
-    mov ax, 0 
+    out dx, al
-    mov es, ax
+
-    mov bx, 0x7e00 ; 2nd stage bootloader location
+    mov dx, 0x1F2       ; Sector count port
+    mov al, 15          ; number of sectors to read
+    out dx, al
+
+    inc dx              ; 0x1F3 - LBA low
+    mov al, 1           ; LBA 1 = 2nd disk sector (0-based), bits 0-7 of LBA
+    out dx, al
+
+    inc dx              ; 0x1F4 - LBA mid
+    xor ax, ax          ; bits 8-15 of LBA
+    out dx, al
+
+    inc dx              ; 0x1F5 - LBA high
+    ; xor ax, ax        ; bits 16-23 of LBA
+    out dx, al
+
+    inc dx
+    inc dx              ; 0x1F7 - Command port
+    mov al, 0x20        ; Read with retry
+    out dx, al
+
+    call loadSectorLoop
+
+    ;; Parse superblock for first inode block, offset to reserved bootloader
+
+    ;; Read first inode block to memory
+    ;; Each disk block is 4KB or 8 sectors of 512 bytes
+    imul cx, [FIRST_INODE_BLOCK], 8 ; CX = disk sector/LBA of first inode block
+
+    mov bl, 7       ; 8 sectors for a block - 1
+    mov di, 0xb000  ; Address to read into, first inode block = 0xB000-0xC000
+
+    mov dx, 0x1F6   ; flags
+    mov al, 0xE0
+    out dx, al
+
+    mov dx, 0x1F2     
+    mov al, 8         
+    out dx, al
+
+    inc dx            
+    mov al, cl        
+    out dx, al
+
+    inc dx            
+    mov al, ch        
+    out dx, al
+
+    inc dx            
+    xor ax, ax        
+    out dx, al
+
+    inc dx
+    inc dx            
+    mov al, 0x20       
+    out dx, al
+
+    call loadSectorLoop
+
+    ;; Read boot loader inode to memory
+    ;;  inode 2, each inode is 64 bytes in size
+    imul ecx, [EXTENT0], 8                  ; first_block translated to disk sector/LBA
+    imul ebx, [EXTENT0+4], 8                ; length_blocks translated to disk sectors/LBAs
+
+    mov dx, 0x1F2
+    mov al, bl   
+    out dx, al
+
+    inc dx       
+    mov al, cl   
+    out dx, al
+
+    inc dx       
+    mov al, ch   
+    out dx, al
+
+    inc dx       
+    shr ecx, 16
+    mov al, cl   
+    out dx, al
+
+    inc dx       
+    and ch, 0x0F 
+    mov al, ch   
+    or al, 0xE0  
+    out dx, al
+
+    inc dx       
+    mov al, 0x20
+    out dx, al
+
+    dec bl       
+    mov ax, 0x5000
+    mov es, ax   
+    xor di, di   
+
+    call loadSectorLoop
+
+    xor ax, ax
+    mov es, ax          ; ES = 0x0000
+
+    ;; Jump to 2nd stage bootloader here, does not return
+    mov dl, [driveNum]
+    jmp 0x0000:0x7E00
+
+    ;; Poll status port after reading 1 sector
+loadSectorLoop:
+    in al, dx           ; Status register (reading port 1F7h)
+    test al, 8          ; Sector buffer requires servicing 
+    je loadSectorLoop   ; Keep trying until sector buffer is ready
+
+    mov cx, 256         ; # of words to read for 1 sector
+    mov dx, 0x1F0       ; Data port, reading 
+    rep insw            ; Read bytes from DX port # into DI, CX # of times
     
-    ; CHS Location
+    ;; 400ns delay - Read alternate status register
-    mov al, 4   ; Number of sectors to read (4 = 2kB)
+    mov dx, 0x3F6
-    mov ch, 0   ; Cylinder
+    in al, dx
-    mov dh, 0   ; Head
+    in al, dx
-    mov cl, 2   ; Sector
+    in al, dx
-    mov dl, [driveNum]
+    in al, dx
 
-    mov ah, 2   ; Read from disk
+    cmp bl, 0           ; Sector # to still read
-    int 0x13    ; Read interrupt
+    je .return
 
-    jnc loadPrekernel
+    dec bl
-
+    mov dx, 0x1F7
-    dec byte [counter]
+    jmp loadSectorLoop
-    jnz .read
+.return:
-
+    ret
-diskErr:
+            
-    mov si, diskErrMsg
+;; VARIABLES
-    mov bl, 0x04
-    mov ax, VIDMEM
-    mov es, ax
-    xor di, di
-.printLoop:
-    movsb
-    mov [es:di], bl
-    inc di
-    cmp byte [si], 0
-    jne .printLoop
-
-    cli
-    hlt
-
-loadPrekernel:
-    mov byte [counter], 3
-
-.read:
-    ; Location
-    mov ax, 0x5000 ; Making es 0x5000 will load the prekernel at 0x50000
-    mov es, ax
-    xor bx, bx
-    
-    ; CHS Location
-    mov al, 10  ; Prekernel size
-    mov ch, 0   ; Cylinder
-    mov dh, 0   ; Head
-    mov cl, 6   ; Sector
-    mov dl, [driveNum]
-
-    mov ah, 2   ; Read from disk
-    int 0x13    ; Read interrupt
-    
-    jnc nextStage
-    dec byte [counter]
-    jnz .read
-
-;; Far jump to second stage bootloader
-nextStage:
-    mov dl, [driveNum]
-    jmp 0x0000:0x7e00
-
-;; Data
 driveNum: db 0
-counter: db 3
 
-; Strings
+;; Boot sector magic
-diskErrMsg: db "Failed while reading from disk!", 0
+times 510-($-$$) db 0   ; Padding
-
-times 510-($-$$) db 0
 dw 0xaa55
 

src/stage2.asm

@@ -2,8 +2,7 @@
 [org 0x7e00]
 
 %define STAGE3_LOC 0x50000
-%define VIDMEM 0xb800
+%define MODE_INFO_BLOCK_LOC 0x6000
-%define MODE_INFO_BLOCK_LOC 0x9000
 
 start:
     mov [driveNum], dl
@@ -12,9 +11,9 @@ start:
     xor ax, ax
     mov es, ax
 
-memMapEntries equ 0x8500
+memMapEntries equ 0x7000
 getMemoryMap:
-    mov di, 0x8504 ; 4 bytes after memMapEntries
+    mov di, memMapEntries + 4 ; 4 bytes after memMapEntries
     xor ebx, ebx
     xor bp, bp
     mov edx, "PAMS" ; SMAP in little endian
@@ -370,9 +369,9 @@ DATA_SEG equ GDT.dataDescriptor - GDT.start
 
 ;; VBE Stuff
 ;; !! IF YOU WANT TO SELECT ANY VALUE IN THE SETUP, SET THESE TO ZERO !!
-width: dw 1920
+width: dw 0
-height: dw 1080
+height: dw 0
-bpp: db 32
+bpp: db 0
 
 offset: dw 0
 _segment: dw 0 ; segment is a keyword

src/stage3.c

@@ -2,34 +2,40 @@
 #include <memory/virtual.h>
 #include <memory/addresses.h>
 #include <disk/disk.h>
-#include <disk/filesys.h>
+//#include <disk/filesys.h>
 #include <screen/gfxmode.h>
 
+#include <fs/fs.h>
+
+uint8_t loadFile(char* filename, void* dest);
+
 __attribute__ ((section("entry")))
 void main() {
-    diskRead(15, 1, filetable); // Load filetable into memory; TODO: Make a filetableUpdate() function that just keeps the stored and memory verisons in sync
-    
     // Physical memory manager setup
     uint32_t smapEntryCount = *(uint32_t*)SMAP_ENTRY_COUNT;
-    smapEntry_t* smapEntries = (smapEntry_t*)SMAP_ENTRIES; // After a unit32_t
+    smapEntry_t* smapEntries = (smapEntry_t*)SMAP_ENTRIES;
-    uint32_t totalMemory = smapEntries[smapEntryCount - 1].baseAddress + smapEntries[smapEntryCount - 1].length - 1;
+    smapEntries += smapEntryCount - 1;
+    uint32_t totalMemory = smapEntries->baseAddress + smapEntries->length - 1;
 
     setupPhysicalMemoryManager(MEMMAP_AREA, totalMemory);
 
+    smapEntries = (smapEntry_t*)SMAP_ENTRIES;
     for (uint32_t i = 0; i < smapEntryCount; i++) {
         if (smapEntries[i].type == 1) {
             initMemoryRegion(smapEntries[i].baseAddress, smapEntries[i].length);
         }
     }
 
-    deinitMemoryRegion(0x1000, 0x9000); // Reserve kernel memory (under 0xa000)
+    deinitMemoryRegion(0x1000, 0x11000); // Reserve kernel memory (under 0x12000)
     deinitMemoryRegion(MEMMAP_AREA, maxBlocks / BLOCKS_PER_BYTE);
 
-    // Load kernel into memory
+    // Load root dir, find kernel INode and parse it
-    if (readFile("kernel.bin", (void*)KERNEL_LOC) != 0) { // Check if kernel.bin was loaded
+    superBlock_t* superblock = (superBlock_t*)SUPERBLOCK_LOC;
-        // TODO: Add error messages
+    superblock->rootInodePtr = BOOT_FIRST_INODE_LOC + sizeof(inode_t);
-        while (1);
+    diskRead(superblock->firstDataBlock * 8, 8, (void*)SCRATCH_BLOCK_LOC);
-    }
+
+    if (loadFile("kernel.bin", (void*)KERNEL_LOC) != 0) __asm__ volatile ("cli; hlt" : : "a"(0xDeadBeef));
+    if (loadFile("term16n.fnt", (void*)FONT_LOC) != 0) __asm__ volatile ("cli; hlt" : : "a"(0xDeadBeef));
 
     // Virtual memory manager setup
     if (setupVirtualMemoryManager() != 0) {
@@ -60,3 +66,33 @@ void main() {
     ((void(*)(void))0xC0000000)();
 }
 
+uint8_t loadFile(char* filename, void* dest) {
+    dirEntry_t* dirEntry = (dirEntry_t*)SCRATCH_BLOCK_LOC;
+    while (dirEntry->name[0] != '\0') {
+        if (strcmp(dirEntry->name, filename) == 0) break;
+        dirEntry++;
+    }
+
+    if (dirEntry->name[0] == '\0') return 1;
+
+    inode_t* inode = (inode_t*)BOOT_FIRST_INODE_LOC;
+    while (inode->id != dirEntry->id) {
+        inode++;
+    }
+
+    uint32_t totalBlocks = bytesToBlocks(inode->sizeBytes);
+    uint32_t addressOffset = 0;
+
+    for (uint8_t i = 0; i < 4 && totalBlocks > 0; i++) {
+        diskRead(inode->extent[i].firstBlock * 8, inode->extent[i].length * 8, dest + addressOffset);
+        addressOffset += inode->extent[i].length * FS_BLOCK_SIZE;
+        totalBlocks -= inode->extent[i].length;
+    }
+
+    if (totalBlocks > 0) {
+        // TODO: Indirect extents
+    }
+
+    return 0;
+}
+