WebSVN – Kolibri OS – Blame – /kernel/trunk/fs/ext2/blocks.asm

Rev	Author	Line No.	Line
3935	shikhin	1	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		2	;; ;;
		3	;; Contains ext2 block handling code. ;;
		4	;; ;;
		5	;; Copyright (C) KolibriOS team 2004-2013. All rights reserved. ;;
		6	;; Distributed under the terms of the new BSD license. ;;
		7	;; ;;
		8	;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
		9
		10	;---------------------------------------------------------------------
		11	; Write ext2 block from memory to disk.
		12	; Input: eax = i_block (block number in ext2 terms);
		13	; ebx = buffer address
		14	; ebp = pointer to EXTFS
		15	; Output: eax = error code (0 implies no error)
		16	;---------------------------------------------------------------------
		17	ext2_block_write:
		18	push edx ebx ecx
		19
		20	mov edx, fs_write32_sys
		21	jmp ext2_block_modify
		22
		23	;---------------------------------------------------------------------
		24	; Read ext2 block from disk to memory.
		25	; Input: eax = i_block (block number in ext2 terms);
		26	; ebx = address of where to read block
		27	; ebp = pointer to EXTFS
		28	; Output: eax = error code (0 implies no error)
		29	;---------------------------------------------------------------------
		30	ext2_block_read:
		31	push edx ebx ecx
		32
		33	mov edx, fs_read32_sys
		34	jmp ext2_block_modify
		35
		36	;---------------------------------------------------------------------
		37	; Modify ext2 block.
		38	; Input: eax = i_block (block number in ext2 terms);
		39	; ebx = I/O buffer address;
		40	; edx = fs_read/write32_sys
		41	; ebp = pointer to EXTFS
		42	; edx, ebx, ecx on stack.
		43	; Output: eax = error code (0 implies no error)
		44	;---------------------------------------------------------------------
		45	ext2_block_modify:
		46	; Get block number in hard-disk terms in eax.
		47	mov ecx, [ebp + EXTFS.log_block_size]
		48	shl eax, cl
		49	mov ecx, eax
		50	push [ebp + EXTFS.count_block_in_block]
		51
		52	@@:
		53	mov eax, ecx
		54	call edx
		55	test eax, eax
		56	jnz .fail
		57
		58	inc ecx
		59	add ebx, 512
		60	dec dword[esp]
		61	jnz @B
		62
		63	xor eax, eax
		64	@@:
		65	pop ecx
		66	pop ecx ebx edx
		67	ret
		68
		69	.fail:
		70	mov eax, ERROR_DEVICE
		71	jmp @B
		72
		73	;---------------------------------------------------------------------
		74	; Zeroes a block.
		75	; Input: ebx = block ID.
		76	; ebp = pointer to EXTFS.
		77	; Output: eax = error code.
		78	;---------------------------------------------------------------------
		79	ext2_block_zero:
		80	push ebx
		81
		82	mov eax, ebx
		83	mov ebx, [ebp + EXTFS.ext2_temp_block]
		84	call ext2_block_read
		85	test eax, eax
		86	jnz .return
		87
		88	push edi ecx
		89	xor eax, eax
		90	mov ecx, [ebp + EXTFS.block_size]
		91	mov edi, [ebp + EXTFS.ext2_temp_block]
		92	rep stosb
		93	pop ecx edi
		94
		95	mov eax, [esp]
		96	call ext2_block_write
		97
		98	.return:
		99	pop ebx
		100	ret
		101
		102	;---------------------------------------------------------------------
		103	; Allocates a block.
		104	; Input: eax = inode ID for "preference".
		105	; ebp = pointer to EXTFS.
		106	; Output: Block marked as set in block group.
		107	; eax = error code.
		108	; ebx = block ID.
		109	;---------------------------------------------------------------------
		110	ext2_block_alloc:
		111	push [ebp + EXTFS.superblock + EXT2_SB_STRUC.blocks_count]
		112	push EXT2_BLOCK_GROUP_DESC.free_blocks_count
		113	push [ebp + EXTFS.superblock + EXT2_SB_STRUC.blocks_per_group]
		114
		115	lea ebx, [ebp + EXTFS.superblock + EXT2_SB_STRUC.free_block_count]
		116	push ebx
		117
		118	push ext2_bg_read_blk_bitmap
		119
		120	call ext2_resource_alloc
		121
		122	ret
		123
		124	;---------------------------------------------------------------------
		125	; Zero-allocates a block.
		126	; Input: eax = inode ID for "preference".
		127	; ebp = pointer to EXTFS.
		128	; Output: Block marked as set in block group.
		129	; eax = error code.
		130	; ebx = block ID.
		131	;---------------------------------------------------------------------
		132	ext2_block_calloc:
		133	call ext2_block_alloc
		134	test eax, eax
		135	jnz @F
		136
		137	call ext2_block_zero
		138	@@:
		139	ret
		140
		141	;---------------------------------------------------------------------
		142	; Frees a block.
		143	; Input: eax = block ID.
		144	; ebp = pointer to EXTFS.
		145	; Output: Block marked as free in block group.
		146	; eax = error code.
		147	;---------------------------------------------------------------------
		148	ext2_block_free:
		149	push edi ecx
		150
		151	mov edi, ext2_bg_read_blk_bitmap
		152	xor ecx, ecx
		153	call ext2_resource_free
		154
		155	pop ecx edi
		156	ret
		157
		158
		159	;---------------------------------------------------------------------
		160	; Find parent from file path in block.
		161	; Input: esi = file path.
		162	; ebx = pointer to directory block.
		163	; ebp = pointer to EXTFS structure.
		164	; Output: esi = name without parent, or not changed.
		165	; ebx = directory record matched.
		166	;---------------------------------------------------------------------
		167	ext2_block_find_parent:
		168	sub esp, 256 ; Space for EXT2 filename.
		169	mov edx, ebx
		170	add edx, [ebp + EXTFS.block_size] ; Save block end.
		171
		172	.start_rec:
		173	cmp [ebx + EXT2_DIR_STRUC.inode], 0
		174	jz .next_rec
		175
		176	mov edi, esp
		177	push esi
		178	movzx ecx, [ebx + EXT2_DIR_STRUC.name_len]
		179	lea esi, [ebx + EXT2_DIR_STRUC.name]
		180	call utf8_to_cp866
		181
		182	mov ecx, edi
		183	lea edi, [esp + 4]
		184	sub ecx, edi ; Number of bytes in resulting string.
		185
		186	mov esi, [esp]
		187
		188	; esi: original file path.
		189	; edi: converted string stored on stack.
		190	; ecx: size of converted string.
		191	@@:
		192	; If no bytes left in resulting string, test it.
		193	jecxz .test_find
		194	dec ecx
		195
		196	lodsb
		197	call char_toupper
		198
		199	mov ah, [edi]
		200	inc edi
		201	xchg al, ah
		202	call char_toupper
		203
		204	; If both are same, check next byte.
		205	cmp al, ah
		206	je @B
		207	@@: ; Doesn't match.
		208	pop esi
		209
		210	.next_rec:
		211	movzx eax, [ebx + EXT2_DIR_STRUC.rec_len]
		212	add ebx, eax ; Go to next record.
		213	cmp ebx, edx ; Check if this is the end.
		214	jb .start_rec
		215
		216	add esp, 256
		217	ret
		218
		219	.test_find:
		220	cmp byte [esi], 0
		221	je .ret ; The end reached.
		222	cmp byte [esi], '/' ; If not end of directory name, not matched.
		223	jne @B
		224	inc esi
		225
		226	.ret:
		227	add esp, 256 + 4
		228	ret
		229
		230	;---------------------------------------------------------------------
		231	; Finds free space in a directory block, modifying last entry appropriately.
		232	; Input: ebp = pointer to EXTFS.
		233	; ecx = size of free space required.
		234	; [EXTFS.ext2_temp_block] contains the block relevant.
		235	; Output: edi = free entry.
		236	; rec_len of free entry is set.
		237	; eax = error code; if the block doesn't link to the next one, this is 0x00000001 on failure.
		238	; ; else, 0xFFFFFFFF.
		239	;---------------------------------------------------------------------
		240	ext2_block_find_fspace:
		241	push ebx edx
		242
		243	mov edi, [ebp + EXTFS.ext2_temp_block]
		244	mov edx, edi
		245	add edx, [ebp + EXTFS.block_size]
		246
		247	@@:
		248	movzx eax, [edi + EXT2_DIR_STRUC.rec_len]
		249	test eax, eax
		250	jz .zero_len
		251
		252	cmp [edi + EXT2_DIR_STRUC.inode], 0
		253	je .unused_entry
		254
		255	; It's a used entry, so see if we can fit it between current one and next.
		256	; Subtract the size used by the name and the structure from rec_len.
		257	movzx ebx, [edi + EXT2_DIR_STRUC.name_len]
		258	add ebx, 8 + 3
		259	and ebx, 0xfffffffc ; Align it on the next 4-byte boundary.
		260
		261	sub eax, ebx
		262	add edi, ebx
		263	cmp eax, ecx
		264	jb .next_iter
		265
		266	sub edi, ebx
		267	mov [edi + EXT2_DIR_STRUC.rec_len], bx ; Make previous entry point to us.
		268	add edi, ebx
		269
		270	mov [edi + EXT2_DIR_STRUC.rec_len], ax ; Make current entry point to next one.
		271	jmp .found
		272
		273	.unused_entry:
		274	; It's an unused inode.
		275	cmp eax, ecx
		276	jge .found
		277
		278	.next_iter:
		279	add edi, eax
		280	cmp edi, edx
		281	jb @B
		282
		283	.not_found:
		284	xor eax, eax
		285	not eax
		286	jmp .ret
		287
		288	; Zero length entry means we have the rest of the block for us.
		289	.zero_len:
		290	mov eax, edx
		291	sub eax, edi
		292
		293	; Point to next block.
		294	mov [edi + EXT2_DIR_STRUC.rec_len], ax
		295
		296	cmp eax, ecx
		297	jge .fits
		298
		299	mov [edi + EXT2_DIR_STRUC.inode], 0
		300
		301	; It doesn't fit, but the block doesn't link to the next block.
		302	xor eax, eax
		303	inc eax
		304	jmp .ret
		305
		306	.fits:
		307	mov [edi + EXT2_DIR_STRUC.rec_len], cx
		308
		309	.found:
		310	xor eax, eax
		311
		312	.ret:
		313	pop edx ebx
		314	ret
		315
		316	;---------------------------------------------------------------------
		317	; Gets the block group's descriptor.
		318	; Input: eax = block group.
		319	; Output: eax = if zero, error; else, points to block group descriptor.
		320	; [EXTFS.ext2_temp_block] contains relevant block.
		321	; ebp = pointer to EXTFS.
		322	;---------------------------------------------------------------------
		323	ext2_bg_read_desc:
		324	push edx ebx
		325	mov edx, 32
		326	mul edx ; Get index of descriptor in global_desc_table.
		327
		328	; eax: block group descriptor offset relative to global descriptor table start
		329	; Find the block this block descriptor is in.
		330	div [ebp + EXTFS.block_size]
		331	add eax, [ebp + EXTFS.superblock + EXT2_SB_STRUC.first_data_block]
		332	inc eax
		333	mov ebx, [ebp + EXTFS.ext2_temp_block]
		334	call ext2_block_read
		335	test eax, eax
		336	jnz .fail
		337
		338	add ebx, edx ; edx: local index of descriptor inside block
		339	mov eax, ebx
		340
		341	.return:
		342	pop ebx edx
		343	ret
		344
		345	.fail:
		346	xor eax, eax
		347	jmp .return
		348
		349	;---------------------------------------------------------------------
		350	; Writes a block group's descriptor.
		351	; Input: eax = block group.
		352	; [EXTFS.ext2_temp_data] contains the block relevant.
		353	; ebp = pointer to EXTFS.
		354	; Output: eax = error code.
		355	;---------------------------------------------------------------------
		356	ext2_bg_write_desc:
		357	push edx ebx
		358	mov edx, 32
		359	mul edx ; Get index of descriptor in global_desc_table.
		360
		361	; eax: block group descriptor offset relative to global descriptor table start
		362	; Find the block this block descriptor is in.
		363	div [ebp + EXTFS.block_size]
		364	add eax, [ebp + EXTFS.superblock + EXT2_SB_STRUC.first_data_block]
		365	inc eax
		366	mov ebx, [ebp + EXTFS.ext2_temp_block]
		367	call ext2_block_write
		368
		369	.return:
		370	pop ebx edx
		371	ret
		372
		373	;---------------------------------------------------------------------
		374	; Gets the block group's block bitmap.
		375	; Input: eax = block group.
		376	; Output: eax = if zero, error; else, points to block group descriptor.
		377	; ebx = block bitmap's block (hard disk).
		378	;---------------------------------------------------------------------
		379	ext2_bg_read_blk_bitmap:
		380	push ecx
		381
		382	call ext2_bg_read_desc
		383	test eax, eax
		384	jz .fail
		385
		386	mov ebx, [eax + EXT2_BLOCK_GROUP_DESC.block_bitmap] ; Block number of block group bitmap - in ext2 terms.
		387
		388	.return:
		389	pop ecx
		390	ret
		391
		392	.fail:
		393	xor eax, eax
		394	jmp .return
		395
		396	;---------------------------------------------------------------------
		397	; Updates superblock, plus backups.
		398	; Input: ebp = pointer to EXTFS.
		399	; Output: eax = error code.
		400	;---------------------------------------------------------------------
		401	ext2_sb_update:
		402	push ebx
		403
		404	mov eax, 2
		405	lea ebx, [ebp + EXTFS.superblock]
		406	call fs_write32_sys
		407
		408	pop ebx

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(root)/kernel/trunk/fs/ext2/blocks.asm – Rev 3935