[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
#include <stdlib.h>

#include <linux/ext2_fs.h>

#include "ext2fs.h"

#ifdef 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 blk_t _BMAP_INLINE_ block_bmap(ext2_filsys fs, char *buf, blk_t nr)
{
	blk_t tmp;

	tmp = ((blk_t *) buf)[nr];

	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
	    (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
		return ext2fs_swab32(tmp);

	return tmp;
}

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) {
		buf = malloc(fs->blocksize * 2);
		if (!buf)
			return EXT2_NO_MEMORY;
		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)
		free(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
	17	#include <stdlib.h>
	18
	19	#include <linux/ext2_fs.h>
	20
	21	#include "ext2fs.h"
	22
	23	#ifdef NO_INLINE_FUNCS
	24	#define _BMAP_INLINE_ __inline__
	25	#else
	26	#define _BMAP_INLINE_
	27	#endif
	28
	29	extern errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino,
	30	struct ext2_inode *inode,
	31	char *block_buf, int bmap_flags,
	32	blk_t block, blk_t *phys_blk);
	33
	34	#define BMAP_ALLOC 1
	35
	36	#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
	37
	38	static blk_t _BMAP_INLINE_ block_bmap(ext2_filsys fs, char *buf, blk_t nr)
	39	{
	40	blk_t tmp;
	41
	42	tmp = ((blk_t *) buf)[nr];
	43
	44	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	45	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
	46	return ext2fs_swab32(tmp);
	47
	48	return tmp;
	49	}
	50
	51	static errcode_t _BMAP_INLINE_ block_ind_bmap(ext2_filsys fs, int flags,
	52	blk_t ind, char *block_buf,
	53	int *blocks_alloc,
	54	blk_t nr, blk_t *ret_blk)
	55	{
	56	errcode_t retval;
	57	blk_t b;
	58
	59	if (!ind) {
	60	*ret_blk = 0;
	61	return 0;
	62	}
	63	retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
	64	if (retval)
65	return retval;
66
67	b = ((blk_t *) block_buf)[nr];
68
69	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
70	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
71	b = ext2fs_swab32(b);
72
73	if (!b && (flags & BMAP_ALLOC)) {
74	b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
75	retval = ext2fs_alloc_block(fs, b,
76	block_buf + fs->blocksize, &b);
77	if (retval)
78	return retval;
79
80	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
81	(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
82	((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
83	else
84	((blk_t *) block_buf)[nr] = b;
85
86	retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
87	if (retval)
88	return retval;
89
90	(*blocks_alloc)++;
91	}
92
93	*ret_blk = b;
94	return 0;
95	}
96
97	static errcode_t _BMAP_INLINE_ block_dind_bmap(ext2_filsys fs, int flags,
98	blk_t dind, char *block_buf,
99	int *blocks_alloc,
100	blk_t nr, blk_t *ret_blk)
101	{
102	blk_t b;
103	errcode_t retval;
104	int addr_per_block;
105
106	addr_per_block = fs->blocksize >> 2;
107
108	retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
109	nr / addr_per_block, &b);
110	if (retval)
111	return retval;
112	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
113	nr % addr_per_block, ret_blk);
114	return retval;
115	}
116
117	static errcode_t _BMAP_INLINE_ block_tind_bmap(ext2_filsys fs, int flags,
118	blk_t tind, char *block_buf,
119	int *blocks_alloc,
120	blk_t nr, blk_t *ret_blk)
121	{
122	blk_t b;
123	errcode_t retval;
124	int addr_per_block;
125
126	addr_per_block = fs->blocksize >> 2;
127
128	retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
129	nr / addr_per_block, &b);
130	if (retval)
131	return retval;
132	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
133	nr % addr_per_block, ret_blk);
134	return retval;
135	}
136
137	errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino, struct ext2_inode *inode,
138	char *block_buf, int bmap_flags, blk_t block,
139	blk_t *phys_blk)
140	{
141	struct ext2_inode inode_buf;
142	int addr_per_block;
143	blk_t b;
144	char *buf = 0;
145	errcode_t retval = 0;
146	int blocks_alloc = 0;
147
148	*phys_blk = 0;
149
150	/* Read inode structure if necessary */
151	if (!inode) {
152	retval = ext2fs_read_inode(fs, ino, &inode_buf);
153	if (!retval)
154	return retval;
155	inode = &inode_buf;
156	}
157	addr_per_block = fs->blocksize >> 2;
158
159	if (!block_buf) {
160	buf = malloc(fs->blocksize * 2);
161	if (!buf)
162	return EXT2_NO_MEMORY;
163	block_buf = buf;
164	}
165
166	if (block < EXT2_NDIR_BLOCKS) {
167	*phys_blk = inode_bmap(inode, block);
168	b = block ? inode_bmap(inode, block-1) : 0;
169
170	if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
171	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
172	if (retval)
173	goto done;
174	inode_bmap(inode, block) = b;
175	blocks_alloc++;
176	*phys_blk = b;
177	}
178	goto done;
179	}
180
181	/* Indirect block */
182	block -= EXT2_NDIR_BLOCKS;
183	if (block < addr_per_block) {
184	b = inode_bmap(inode, EXT2_IND_BLOCK);
185	if (!b) {
186	if (!(bmap_flags & BMAP_ALLOC))
187	goto done;
188
189	b = inode_bmap(inode, EXT2_IND_BLOCK-1);
190	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
191	if (retval)
192	goto done;
193	inode_bmap(inode, EXT2_IND_BLOCK) = b;
194	blocks_alloc++;
195	}
196	retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
197	&blocks_alloc, block, phys_blk);
198	goto done;
199	}
200
201	/* Doubly indirect block */
202	block -= addr_per_block;
203	if (block < addr_per_block * addr_per_block) {
204	b = inode_bmap(inode, EXT2_DIND_BLOCK);
205	if (!b) {
206	if (!(bmap_flags & BMAP_ALLOC))
207	goto done;
208
209	b = inode_bmap(inode, EXT2_IND_BLOCK);
210	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
211	if (retval)
212	goto done;
213	inode_bmap(inode, EXT2_DIND_BLOCK) = b;
214	blocks_alloc++;
215	}
216	retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
217	&blocks_alloc, block, phys_blk);
218	goto done;
219	}
220
221	/* Triply indirect block */
222	block -= addr_per_block * addr_per_block;
223	b = inode_bmap(inode, EXT2_TIND_BLOCK);
224	if (!b) {
225	if (!(bmap_flags & BMAP_ALLOC))
226	goto done;
227
228	b = inode_bmap(inode, EXT2_DIND_BLOCK);
229	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
230	if (retval)
231	goto done;
232	inode_bmap(inode, EXT2_TIND_BLOCK) = b;
233	blocks_alloc++;
234	}
235	retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
236	&blocks_alloc, block, phys_blk);
237	done:
238	if (buf)
239	free(buf);
240	if ((retval == 0) && blocks_alloc) {
241	inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
242	retval = ext2fs_write_inode(fs, ino, inode);
243	}
244	return retval;
245	}
246
247
248