[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 <linux/ext2_fs.h>

#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 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) {
		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 TT	17
	18	#include <linux/ext2_fs.h>
	19
	20	#include "ext2fs.h"
	21
78d8f90f	22	#if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
30fab293 TT	23	#define _BMAP_INLINE_ __inline__
	24	#else
	25	#define _BMAP_INLINE_
	26	#endif
	27
	28	extern errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino,
	29	struct ext2_inode *inode,
	30	char *block_buf, int bmap_flags,
	31	blk_t block, blk_t *phys_blk);
	32
	33	#define BMAP_ALLOC 1
	34
	35	#define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
	36
	37	static blk_t _BMAP_INLINE_ block_bmap(ext2_filsys fs, char *buf, blk_t nr)
	38	{
	39	blk_t tmp;
	40
	41	tmp = ((blk_t *) buf)[nr];
	42
	43	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	44	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
	45	return ext2fs_swab32(tmp);
	46
	47	return tmp;
	48	}
	49
	50	static errcode_t _BMAP_INLINE_ block_ind_bmap(ext2_filsys fs, int flags,
	51	blk_t ind, char *block_buf,
	52	int *blocks_alloc,
	53	blk_t nr, blk_t *ret_blk)
	54	{
	55	errcode_t retval;
	56	blk_t b;
	57
	58	if (!ind) {
	59	*ret_blk = 0;
	60	return 0;
	61	}
	62	retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
	63	if (retval)
	64	return retval;
	65
	66	b = ((blk_t *) block_buf)[nr];
	67
	68	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	69	(fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
	70	b = ext2fs_swab32(b);
	71
	72	if (!b && (flags & BMAP_ALLOC)) {
	73	b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
	74	retval = ext2fs_alloc_block(fs, b,
	75	block_buf + fs->blocksize, &b);
	76	if (retval)
	77	return retval;
	78
	79	if ((fs->flags & EXT2_FLAG_SWAP_BYTES) \|\|
	80	(fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
	81	((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
	82	else
	83	((blk_t *) block_buf)[nr] = b;
	84
	85	retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
	86	if (retval)
87	return retval;
88
89	(*blocks_alloc)++;
90	}
91
92	*ret_blk = b;
93	return 0;
94	}
95
96	static errcode_t _BMAP_INLINE_ block_dind_bmap(ext2_filsys fs, int flags,
97	blk_t dind, char *block_buf,
98	int *blocks_alloc,
99	blk_t nr, blk_t *ret_blk)
100	{
101	blk_t b;
102	errcode_t retval;
103	int addr_per_block;
104
105	addr_per_block = fs->blocksize >> 2;
106
107	retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
108	nr / addr_per_block, &b);
109	if (retval)
110	return retval;
111	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
112	nr % addr_per_block, ret_blk);
113	return retval;
114	}
115
116	static errcode_t _BMAP_INLINE_ block_tind_bmap(ext2_filsys fs, int flags,
117	blk_t tind, char *block_buf,
118	int *blocks_alloc,
119	blk_t nr, blk_t *ret_blk)
120	{
121	blk_t b;
122	errcode_t retval;
123	int addr_per_block;
124
125	addr_per_block = fs->blocksize >> 2;
126
127	retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
128	nr / addr_per_block, &b);
129	if (retval)
130	return retval;
131	retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
132	nr % addr_per_block, ret_blk);
133	return retval;
134	}
135
136	errcode_t ext2fs_bmap(ext2_filsys fs, ino_t ino, struct ext2_inode *inode,
137	char *block_buf, int bmap_flags, blk_t block,
138	blk_t *phys_blk)
139	{
140	struct ext2_inode inode_buf;
141	int addr_per_block;
142	blk_t b;
143	char *buf = 0;
144	errcode_t retval = 0;
145	int blocks_alloc = 0;
146
147	*phys_blk = 0;
148
149	/* Read inode structure if necessary */
150	if (!inode) {
151	retval = ext2fs_read_inode(fs, ino, &inode_buf);
152	if (!retval)
153	return retval;
154	inode = &inode_buf;
155	}
156	addr_per_block = fs->blocksize >> 2;
157
158	if (!block_buf) {
7b4e4534 TT	159	retval = ext2fs_get_mem(fs->blocksize * 2, (void **) &buf);
	160	if (retval)
	161	return retval;
30fab293 TT	162	block_buf = buf;
	163	}
	164
	165	if (block < EXT2_NDIR_BLOCKS) {
	166	*phys_blk = inode_bmap(inode, block);
	167	b = block ? inode_bmap(inode, block-1) : 0;
	168
	169	if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
	170	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	171	if (retval)
	172	goto done;
	173	inode_bmap(inode, block) = b;
	174	blocks_alloc++;
	175	*phys_blk = b;
	176	}
	177	goto done;
	178	}
	179
	180	/* Indirect block */
	181	block -= EXT2_NDIR_BLOCKS;
	182	if (block < addr_per_block) {
	183	b = inode_bmap(inode, EXT2_IND_BLOCK);
	184	if (!b) {
	185	if (!(bmap_flags & BMAP_ALLOC))
	186	goto done;
	187
	188	b = inode_bmap(inode, EXT2_IND_BLOCK-1);
	189	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	190	if (retval)
	191	goto done;
	192	inode_bmap(inode, EXT2_IND_BLOCK) = b;
	193	blocks_alloc++;
	194	}
	195	retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
	196	&blocks_alloc, block, phys_blk);
	197	goto done;
	198	}
	199
	200	/* Doubly indirect block */
	201	block -= addr_per_block;
	202	if (block < addr_per_block * addr_per_block) {
	203	b = inode_bmap(inode, EXT2_DIND_BLOCK);
	204	if (!b) {
	205	if (!(bmap_flags & BMAP_ALLOC))
	206	goto done;
	207
	208	b = inode_bmap(inode, EXT2_IND_BLOCK);
	209	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
	210	if (retval)
	211	goto done;
	212	inode_bmap(inode, EXT2_DIND_BLOCK) = b;
	213	blocks_alloc++;
	214	}
	215	retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
	216	&blocks_alloc, block, phys_blk);
	217	goto done;
	218	}
	219
	220	/* Triply indirect block */
	221	block -= addr_per_block * addr_per_block;
	222	b = inode_bmap(inode, EXT2_TIND_BLOCK);
	223	if (!b) {
	224	if (!(bmap_flags & BMAP_ALLOC))
	225	goto done;
226
227	b = inode_bmap(inode, EXT2_DIND_BLOCK);
228	retval = ext2fs_alloc_block(fs, b, block_buf, &b);
229	if (retval)
230	goto done;
231	inode_bmap(inode, EXT2_TIND_BLOCK) = b;
232	blocks_alloc++;
233	}
234	retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
235	&blocks_alloc, block, phys_blk);
236	done:
237	if (buf)
7b4e4534	238	ext2fs_free_mem((void **) &buf);
30fab293 TT	239	if ((retval == 0) && blocks_alloc) {
	240	inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
	241	retval = ext2fs_write_inode(fs, ino, inode);
	242	}
	243	return retval;
	244	}
	245
	246
	247