[thirdparty/e2fsprogs.git] / lib / ext2fs / bmap.c

/*
 * bmap.c --- logical to phiscal block mapping
 *
 * Copyright (C) 1997 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 */

#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif

#if EXT2_FLAT_INCLUDES
#include "ext2_fs.h"
#else
#include <linux/ext2_fs.h>
#endif

#include "ext2fs.h"

#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
#define _BMAP_INLINE_	__inline__
#else
#define _BMAP_INLINE_
#endif

extern errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino,
			     struct ext2_inode *inode, 
			     char *block_buf, int bmap_flags,
			     blk_t block, blk_t *phys_blk);

#define BMAP_ALLOC	1

#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])

static errcode_t _BMAP_INLINE_ block_ind_bmap(ext2_filsys fs, int flags, 
					      blk_t ind, char *block_buf, 
					      int *blocks_alloc,
					      blk_t nr, blk_t *ret_blk)
{
	errcode_t	retval;
	blk_t		b;

	if (!ind) {
		*ret_blk = 0;
		return 0;
	}
	retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
	if (retval)
		return retval;

	b = ((blk_t *) block_buf)[nr];

	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
	    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
		b = ext2fs_swab32(b);

	if (!b && (flags & BMAP_ALLOC)) {
		b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
		retval = ext2fs_alloc_block(fs, b,
					    block_buf + fs->blocksize, &b);
		if (retval)
			return retval;

		if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
		    (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
			((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
		else
			((blk_t *) block_buf)[nr] = b;

		retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
		if (retval)
			return retval;

		(*blocks_alloc)++;
	}

	*ret_blk = b;
	return 0;
}

static errcode_t _BMAP_INLINE_ block_dind_bmap(ext2_filsys fs, int flags,
					       blk_t dind, char *block_buf, 
					       int *blocks_alloc,
					       blk_t nr, blk_t *ret_blk)
{
	blk_t		b;
	errcode_t	retval;
	int		addr_per_block;
	
	addr_per_block = fs->blocksize >> 2;

	retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
				nr / addr_per_block, &b);
	if (retval)
		return retval;
	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
				nr % addr_per_block, ret_blk);
	return retval;
}

static errcode_t _BMAP_INLINE_ block_tind_bmap(ext2_filsys fs, int flags,
					       blk_t tind, char *block_buf, 
					       int *blocks_alloc,
					       blk_t nr, blk_t *ret_blk)
{
	blk_t		b;
	errcode_t	retval;
	int		addr_per_block;
	
	addr_per_block = fs->blocksize >> 2;

	retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
				 nr / addr_per_block, &b);
	if (retval)
		return retval;
	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
				nr % addr_per_block, ret_blk);
	return retval;
}

errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino, struct ext2_inode *inode,
		      char *block_buf, int bmap_flags, blk_t block,
		      blk_t *phys_blk)
{
	struct ext2_inode inode_buf;
	int addr_per_block;
	blk_t	b;
	char	*buf = 0;
	errcode_t	retval = 0;
	int		blocks_alloc = 0;

	*phys_blk = 0;

	/* Read inode structure if necessary */
	if (!inode) {
		retval = ext2fs_read_inode(fs, ino, &inode_buf);
		if (!retval)
			return retval;
		inode = &inode_buf;
	}
	addr_per_block = fs->blocksize >> 2;

	if (!block_buf) {
		retval = ext2fs_get_mem(fs->blocksize * 2, (void **) &buf);
		if (retval)
			return retval;
		block_buf = buf;
	}

	if (block < EXT2_NDIR_BLOCKS) {
		*phys_blk = inode_bmap(inode, block);
		b = block ? inode_bmap(inode, block-1) : 0;
		
		if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
			retval = ext2fs_alloc_block(fs, b, block_buf, &b);
			if (retval)
				goto done;
			inode_bmap(inode, block) = b;
			blocks_alloc++;
			*phys_blk = b;
		}
		goto done;
	}
	
	/* Indirect block */
	block -= EXT2_NDIR_BLOCKS;
	if (block < addr_per_block) {
		b = inode_bmap(inode, EXT2_IND_BLOCK);
		if (!b) {
			if (!(bmap_flags & BMAP_ALLOC))
			    goto done;

			b = inode_bmap(inode, EXT2_IND_BLOCK-1);
 			retval = ext2fs_alloc_block(fs, b, block_buf, &b);
			if (retval)
				goto done;
			inode_bmap(inode, EXT2_IND_BLOCK) = b;
			blocks_alloc++;
		}
		retval = block_ind_bmap(fs, bmap_flags, b, block_buf, 
					&blocks_alloc, block, phys_blk);
		goto done;
	}
	
	/* Doubly indirect block  */
	block -= addr_per_block;
	if (block < addr_per_block * addr_per_block) {
		b = inode_bmap(inode, EXT2_DIND_BLOCK);
		if (!b) {
			if (!(bmap_flags & BMAP_ALLOC))
			    goto done;

			b = inode_bmap(inode, EXT2_IND_BLOCK);
 			retval = ext2fs_alloc_block(fs, b, block_buf, &b);
			if (retval)
				goto done;
			inode_bmap(inode, EXT2_DIND_BLOCK) = b;
			blocks_alloc++;
		}
		retval = block_dind_bmap(fs, bmap_flags, b, block_buf, 
					 &blocks_alloc, block, phys_blk);
		goto done;
	}

	/* Triply indirect block */
	block -= addr_per_block * addr_per_block;
	b = inode_bmap(inode, EXT2_TIND_BLOCK);
	if (!b) {
		if (!(bmap_flags & BMAP_ALLOC))
			goto done;

		b = inode_bmap(inode, EXT2_DIND_BLOCK);
		retval = ext2fs_alloc_block(fs, b, block_buf, &b);
		if (retval)
			goto done;
		inode_bmap(inode, EXT2_TIND_BLOCK) = b;
		blocks_alloc++;
	}
	retval = block_tind_bmap(fs, bmap_flags, b, block_buf, 
				 &blocks_alloc, block, phys_blk);
done:
	if (buf)
		ext2fs_free_mem((void **) &buf);
	if ((retval == 0) && blocks_alloc) {
		inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
		retval = ext2fs_write_inode(fs, ino, inode);
	}
	return retval;
}
Commit	Line	Data
30fab293 TT	1	/*
	2	* bmap.c --- logical to phiscal block mapping
	3	*
	4	* Copyright (C) 1997 Theodore Ts'o.
	5	*
	6	* %Begin-Header%
	7	* This file may be redistributed under the terms of the GNU Public
	8	* License.
	9	* %End-Header%
	10	*/
	11
	12	#include <stdio.h>
	13	#include <string.h>
	14	#if HAVE_UNISTD_H
	15	#include <unistd.h>
	16	#endif
30fab293	17
b5abe6fa TT	18	#if EXT2_FLAT_INCLUDES
	19	#include "ext2_fs.h"
	20	#else
30fab293	21	#include <linux/ext2_fs.h>
b5abe6fa	22	#endif
30fab293 TT	23
	24	#include "ext2fs.h"
	25
78d8f90f	26	#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
30fab293 TT	27	#define _BMAP_INLINE_ __inline__
	28	#else
	29	#define _BMAP_INLINE_
	30	#endif
	31
	32	extern errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino,
	33	struct ext2_inode *inode,
	34	char *block_buf, int bmap_flags,
	35	blk_t block, blk_t *phys_blk);
	36
	37	#define BMAP_ALLOC 1
	38
	39	#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
	40
30fab293 TT	41	static errcode_t _BMAP_INLINE_ block_ind_bmap(ext2_filsys fs, int flags,
	42	blk_t ind, char *block_buf,
	43	int *blocks_alloc,
	44	blk_t nr, blk_t *ret_blk)
	45	{
	46	errcode_t retval;
	47	blk_t b;
	48
	49	if (!ind) {
	50	*ret_blk = 0;
	51	return 0;
	52	}
	53	retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
	54	if (retval)
	55	return retval;
	56
	57	b = ((blk_t *) block_buf)[nr];
	58
	59	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	60	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
	61	b = ext2fs_swab32(b);
	62
	63	if (!b && (flags & BMAP_ALLOC)) {
	64	b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
	65	retval = ext2fs_alloc_block(fs, b,
	66	block_buf + fs->blocksize, &b);
	67	if (retval)
	68	return retval;
	69
	70	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	71	(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
	72	((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
	73	else
	74	((blk_t *) block_buf)[nr] = b;
	75
	76	retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
	77	if (retval)
	78	return retval;
	79
	80	(*blocks_alloc)++;
	81	}
	82
	83	*ret_blk = b;
	84	return 0;
	85	}
	86
	87	static errcode_t _BMAP_INLINE_ block_dind_bmap(ext2_filsys fs, int flags,
	88	blk_t dind, char *block_buf,
	89	int *blocks_alloc,
	90	blk_t nr, blk_t *ret_blk)
	91	{
	92	blk_t b;
	93	errcode_t retval;
	94	int addr_per_block;
	95
	96	addr_per_block = fs->blocksize >> 2;
	97
	98	retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
	99	nr / addr_per_block, &b);
	100	if (retval)
	101	return retval;
	102	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
	103	nr % addr_per_block, ret_blk);
	104	return retval;
105	}
106
107	static errcode_t _BMAP_INLINE_ block_tind_bmap(ext2_filsys fs, int flags,
108	blk_t tind, char *block_buf,
109	int *blocks_alloc,
110	blk_t nr, blk_t *ret_blk)
111	{
112	blk_t b;
113	errcode_t retval;
114	int addr_per_block;
115
116	addr_per_block = fs->blocksize >> 2;
117
118	retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
119	nr / addr_per_block, &b);
120	if (retval)
121	return retval;
122	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
123	nr % addr_per_block, ret_blk);
124	return retval;
125	}
126
127	errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino, struct ext2_inode *inode,
128	char *block_buf, int bmap_flags, blk_t block,
129	blk_t *phys_blk)
130	{
131	struct ext2_inode inode_buf;
132	int addr_per_block;
133	blk_t b;
134	char *buf = 0;
135	errcode_t retval = 0;
136	int blocks_alloc = 0;
137
138	*phys_blk = 0;
139
140	/* Read inode structure if necessary */
141	if (!inode) {
142	retval = ext2fs_read_inode(fs, ino, &inode_buf);
143	if (!retval)
144	return retval;
145	inode = &inode_buf;
146	}
147	addr_per_block = fs->blocksize >> 2;
148
149	if (!block_buf) {
7b4e4534 TT	150	retval = ext2fs_get_mem(fs->blocksize * 2, (void **) &buf);
	151	if (retval)
	152	return retval;
30fab293 TT	153	block_buf = buf;
	154	}
	155
	156	if (block < EXT2_NDIR_BLOCKS) {
	157	*phys_blk = inode_bmap(inode, block);
	158	b = block ? inode_bmap(inode, block-1) : 0;
	159
	160	if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
	161	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	162	if (retval)
	163	goto done;
	164	inode_bmap(inode, block) = b;
	165	blocks_alloc++;
	166	*phys_blk = b;
	167	}
	168	goto done;
	169	}
	170
	171	/* Indirect block */
	172	block -= EXT2_NDIR_BLOCKS;
	173	if (block < addr_per_block) {
	174	b = inode_bmap(inode, EXT2_IND_BLOCK);
	175	if (!b) {
	176	if (!(bmap_flags & BMAP_ALLOC))
	177	goto done;
	178
	179	b = inode_bmap(inode, EXT2_IND_BLOCK-1);
	180	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	181	if (retval)
	182	goto done;
	183	inode_bmap(inode, EXT2_IND_BLOCK) = b;
	184	blocks_alloc++;
	185	}
	186	retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
	187	&blocks_alloc, block, phys_blk);
	188	goto done;
	189	}
	190
	191	/* Doubly indirect block */
	192	block -= addr_per_block;
	193	if (block < addr_per_block * addr_per_block) {
	194	b = inode_bmap(inode, EXT2_DIND_BLOCK);
	195	if (!b) {
	196	if (!(bmap_flags & BMAP_ALLOC))
	197	goto done;
	198
	199	b = inode_bmap(inode, EXT2_IND_BLOCK);
	200	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	201	if (retval)
	202	goto done;
	203	inode_bmap(inode, EXT2_DIND_BLOCK) = b;
	204	blocks_alloc++;
	205	}
	206	retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
	207	&blocks_alloc, block, phys_blk);
	208	goto done;
	209	}
	210
	211	/* Triply indirect block */
	212	block -= addr_per_block * addr_per_block;
	213	b = inode_bmap(inode, EXT2_TIND_BLOCK);
	214	if (!b) {
	215	if (!(bmap_flags & BMAP_ALLOC))
	216	goto done;
217
218	b = inode_bmap(inode, EXT2_DIND_BLOCK);
219	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
220	if (retval)
221	goto done;
222	inode_bmap(inode, EXT2_TIND_BLOCK) = b;
223	blocks_alloc++;
224	}
225	retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
226	&blocks_alloc, block, phys_blk);
227	done:
228	if (buf)
7b4e4534	229	ext2fs_free_mem((void **) &buf);
30fab293 TT	230	if ((retval == 0) && blocks_alloc) {
	231	inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
	232	retval = ext2fs_write_inode(fs, ino, inode);
	233	}
	234	return retval;
	235	}
	236
	237
	238