;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Contains ext2 block handling code. ;;
;; ;;
;; Copyright (C) KolibriOS team 2013-2014. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision: 4891 $
;---------------------------------------------------------------------
; Write ext2 block from memory to disk.
; Input: eax = i_block (block number in ext2 terms);
; ebx = buffer address
; ebp = pointer to EXTFS
; Output: eax = error code (0 implies no error)
;---------------------------------------------------------------------
ext2_block_write:
push edx ebx ecx
mov edx, fs_write32_sys
jmp ext2_block_modify
;---------------------------------------------------------------------
; Read ext2 block from disk to memory.
; Input: eax = i_block (block number in ext2 terms);
; ebx = address of where to read block
; ebp = pointer to EXTFS
; Output: eax = error code (0 implies no error)
;---------------------------------------------------------------------
ext2_block_read:
push edx ebx ecx
mov edx, fs_read32_sys
jmp ext2_block_modify
;---------------------------------------------------------------------
; Modify ext2 block.
; Input: eax = i_block (block number in ext2 terms);
; ebx = I/O buffer address;
; edx = fs_read/write32_sys
; ebp = pointer to EXTFS
; edx, ebx, ecx on stack.
; Output: eax = error code (0 implies no error)
;---------------------------------------------------------------------
ext2_block_modify:
; Get block number in hard-disk terms in eax.
mov ecx, [ebp + EXTFS.log_block_size]
shl eax, cl
mov ecx, eax
push [ebp + EXTFS.count_block_in_block]
@@:
mov eax, ecx
call edx
test eax, eax
jnz .fail
inc ecx
add ebx, 512
dec dword[esp]
jnz @B
xor eax, eax
@@:
pop ecx
pop ecx ebx edx
ret
.fail:
mov eax, ERROR_DEVICE
jmp @B
;---------------------------------------------------------------------
; Zeroes a block.
; Input: ebx = block ID.
; ebp = pointer to EXTFS.
; Output: eax = error code.
;---------------------------------------------------------------------
ext2_block_zero:
push ebx
mov eax, ebx
mov ebx, [ebp + EXTFS.ext2_temp_block]
call ext2_block_read
test eax, eax
jnz .return
push edi ecx
xor eax, eax
mov ecx, [ebp + EXTFS.block_size]
mov edi, [ebp + EXTFS.ext2_temp_block]
rep stosb
pop ecx edi
mov eax, [esp]
call ext2_block_write
.return:
pop ebx
ret
;---------------------------------------------------------------------
; Allocates a block.
; Input: eax = inode ID for "preference".
; ebp = pointer to EXTFS.
; Output: Block marked as set in block group.
; eax = error code.
; ebx = block ID.
;---------------------------------------------------------------------
ext2_block_alloc:
push [ebp + EXTFS.superblock + EXT2_SB_STRUC.blocks_count]
push EXT2_BLOCK_GROUP_DESC.free_blocks_count
push [ebp + EXTFS.superblock + EXT2_SB_STRUC.blocks_per_group]
lea ebx, [ebp + EXTFS.superblock + EXT2_SB_STRUC.free_block_count]
push ebx
push ext2_bg_read_blk_bitmap
call ext2_resource_alloc
ret
;---------------------------------------------------------------------
; Zero-allocates a block.
; Input: eax = inode ID for "preference".
; ebp = pointer to EXTFS.
; Output: Block marked as set in block group.
; eax = error code.
; ebx = block ID.
;---------------------------------------------------------------------
ext2_block_calloc:
call ext2_block_alloc
test eax, eax
jnz @F
call ext2_block_zero
@@:
ret
;---------------------------------------------------------------------
; Frees a block.
; Input: eax = block ID.
; ebp = pointer to EXTFS.
; Output: Block marked as free in block group.
; eax = error code.
;---------------------------------------------------------------------
ext2_block_free:
push edi ecx
mov edi, ext2_bg_read_blk_bitmap
xor ecx, ecx
call ext2_resource_free
pop ecx edi
ret
;---------------------------------------------------------------------
; Find parent from file path in block.
; Input: esi = file path.
; ebx = pointer to directory block.
; ebp = pointer to EXTFS structure.
; Output: esi = name without parent, or not changed.
; ebx = directory record matched.
;---------------------------------------------------------------------
ext2_block_find_parent:
sub esp, 256 ; Space for EXT2 filename.
mov edx, ebx
add edx, [ebp + EXTFS.block_size] ; Save block end.
.start_rec:
cmp [ebx + EXT2_DIR_STRUC.inode], 0
jz .next_rec
mov edi, esp
push esi
movzx ecx, [ebx + EXT2_DIR_STRUC.name_len]
lea esi, [ebx + EXT2_DIR_STRUC.name]
call utf8_to_cp866
mov ecx, edi
lea edi, [esp + 4]
sub ecx, edi ; Number of bytes in resulting string.
mov esi, [esp]
; esi: original file path.
; edi: converted string stored on stack.
; ecx: size of converted string.
@@:
; If no bytes left in resulting string, test it.
jecxz .test_find
dec ecx
lodsb
call char_toupper
mov ah, [edi]
inc edi
xchg al, ah
call char_toupper
; If both are same, check next byte.
cmp al, ah
je @B
@@: ; Doesn't match.
pop esi
.next_rec:
movzx eax, [ebx + EXT2_DIR_STRUC.rec_len]
add ebx, eax ; Go to next record.
cmp ebx, edx ; Check if this is the end.
jb .start_rec
add esp, 256
ret
.test_find:
cmp byte [esi], 0
je .ret ; The end reached.
cmp byte [esi], '/' ; If not end of directory name, not matched.
jne @B
inc esi
.ret:
add esp, 256 + 4
ret
;---------------------------------------------------------------------
; Finds free space in a directory block, modifying last entry appropriately.
; Input: ebp = pointer to EXTFS.
; ecx = size of free space required.
; [EXTFS.ext2_temp_block] contains the block relevant.
; Output: edi = free entry.
; rec_len of free entry is set.
; eax = error code; if the block doesn't link to the next one, this is 0x00000001 on failure.
; ; else, 0xFFFFFFFF.
;---------------------------------------------------------------------
ext2_block_find_fspace:
push ebx edx
mov edi, [ebp + EXTFS.ext2_temp_block]
mov edx, edi
add edx, [ebp + EXTFS.block_size]
@@:
movzx eax, [edi + EXT2_DIR_STRUC.rec_len]
test eax, eax
jz .zero_len
cmp [edi + EXT2_DIR_STRUC.inode], 0
je .unused_entry
; It's a used entry, so see if we can fit it between current one and next.
; Subtract the size used by the name and the structure from rec_len.
movzx ebx, [edi + EXT2_DIR_STRUC.name_len]
add ebx, 8 + 3
and ebx, 0xfffffffc ; Align it on the next 4-byte boundary.
sub eax, ebx
add edi, ebx
cmp eax, ecx
jb .next_iter
sub edi, ebx
mov [edi + EXT2_DIR_STRUC.rec_len], bx ; Make previous entry point to us.
add edi, ebx
mov [edi + EXT2_DIR_STRUC.rec_len], ax ; Make current entry point to next one.
jmp .found
.unused_entry:
; It's an unused inode.
cmp eax, ecx
jge .found
.next_iter:
add edi, eax
cmp edi, edx
jb @B
.not_found:
xor eax, eax
not eax
jmp .ret
; Zero length entry means we have the rest of the block for us.
.zero_len:
mov eax, edx
sub eax, edi
; Point to next block.
mov [edi + EXT2_DIR_STRUC.rec_len], ax
cmp eax, ecx
jge .fits
mov [edi + EXT2_DIR_STRUC.inode], 0
; It doesn't fit, but the block doesn't link to the next block.
xor eax, eax
inc eax
jmp .ret
.fits:
mov [edi + EXT2_DIR_STRUC.rec_len], cx
.found:
xor eax, eax
.ret:
pop edx ebx
ret
;---------------------------------------------------------------------
; Gets the block group's descriptor.
; Input: eax = block group.
; Output: eax = if zero, error; else, points to block group descriptor.
; [EXTFS.ext2_temp_block] contains relevant block.
; ebp = pointer to EXTFS.
;---------------------------------------------------------------------
ext2_bg_read_desc:
push edx ebx
mov edx, 32
mul edx ; Get index of descriptor in global_desc_table.
; eax: block group descriptor offset relative to global descriptor table start
; Find the block this block descriptor is in.
div [ebp + EXTFS.block_size]
add eax, [ebp + EXTFS.superblock + EXT2_SB_STRUC.first_data_block]
inc eax
mov ebx, [ebp + EXTFS.ext2_temp_block]
call ext2_block_read
test eax, eax
jnz .fail
add ebx, edx ; edx: local index of descriptor inside block
mov eax, ebx
.return:
pop ebx edx
ret
.fail:
xor eax, eax
jmp .return
;---------------------------------------------------------------------
; Writes a block group's descriptor.
; Input: eax = block group.
; [EXTFS.ext2_temp_data] contains the block relevant.
; ebp = pointer to EXTFS.
; Output: eax = error code.
;---------------------------------------------------------------------
ext2_bg_write_desc:
push edx ebx
mov edx, 32
mul edx ; Get index of descriptor in global_desc_table.
; eax: block group descriptor offset relative to global descriptor table start
; Find the block this block descriptor is in.
div [ebp + EXTFS.block_size]
add eax, [ebp + EXTFS.superblock + EXT2_SB_STRUC.first_data_block]
inc eax
mov ebx, [ebp + EXTFS.ext2_temp_block]
call ext2_block_write
.return:
pop ebx edx
ret
;---------------------------------------------------------------------
; Gets the block group's block bitmap.
; Input: eax = block group.
; Output: eax = if zero, error; else, points to block group descriptor.
; ebx = block bitmap's block (hard disk).
;---------------------------------------------------------------------
ext2_bg_read_blk_bitmap:
push ecx
call ext2_bg_read_desc
test eax, eax
jz .fail
mov ebx, [eax + EXT2_BLOCK_GROUP_DESC.block_bitmap] ; Block number of block group bitmap - in ext2 terms.
.return:
pop ecx
ret
.fail:
xor eax, eax
jmp .return
;---------------------------------------------------------------------
; Updates superblock, plus backups.
; Input: ebp = pointer to EXTFS.
; Output: eax = error code.
;---------------------------------------------------------------------
ext2_sb_update:
push ebx
mov eax, 2
lea ebx, [ebp + EXTFS.superblock]
call fs_write32_sys
pop ebx
ret