2 * bmap.c --- logical to physical block mapping
4 * Copyright (C) 1997 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Public
21 #if defined(__GNUC__) && !defined(NO_INLINE_FUNCS)
22 #define _BMAP_INLINE_ __inline__
27 extern errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino,
28 struct ext2_inode *inode,
29 char *block_buf, int bmap_flags,
30 blk_t block, blk_t *phys_blk);
34 #define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
36 static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
37 blk_t ind, char *block_buf,
39 blk_t nr, blk_t *ret_blk)
48 retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
52 b = ((blk_t *) block_buf)[nr];
54 #ifdef EXT2FS_ENABLE_SWAPFS
55 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
56 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
60 if (!b && (flags & BMAP_ALLOC)) {
61 b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
62 retval = ext2fs_alloc_block(fs, b,
63 block_buf + fs->blocksize, &b);
67 #ifdef EXT2FS_ENABLE_SWAPFS
68 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
69 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
70 ((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
73 ((blk_t *) block_buf)[nr] = b;
75 retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
86 static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
87 blk_t dind, char *block_buf,
89 blk_t nr, blk_t *ret_blk)
95 addr_per_block = (blk_t) fs->blocksize >> 2;
97 retval = block_ind_bmap(fs, flags, dind, block_buf, blocks_alloc,
98 nr / addr_per_block, &b);
101 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
102 nr % addr_per_block, ret_blk);
106 static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
107 blk_t tind, char *block_buf,
109 blk_t nr, blk_t *ret_blk)
113 blk_t addr_per_block;
115 addr_per_block = (blk_t) fs->blocksize >> 2;
117 retval = block_dind_bmap(fs, flags, tind, block_buf, blocks_alloc,
118 nr / addr_per_block, &b);
121 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
122 nr % addr_per_block, ret_blk);
126 errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
127 char *block_buf, int bmap_flags, blk_t block,
130 struct ext2_inode inode_buf;
131 blk_t addr_per_block;
134 errcode_t retval = 0;
135 int blocks_alloc = 0;
139 /* Read inode structure if necessary */
141 retval = ext2fs_read_inode(fs, ino, &inode_buf);
146 addr_per_block = (blk_t) fs->blocksize >> 2;
149 retval = ext2fs_get_mem(fs->blocksize * 2, (void **) &buf);
155 if (block < EXT2_NDIR_BLOCKS) {
156 *phys_blk = inode_bmap(inode, block);
157 b = block ? inode_bmap(inode, block-1) : 0;
159 if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
160 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
163 inode_bmap(inode, block) = b;
171 block -= EXT2_NDIR_BLOCKS;
172 if (block < addr_per_block) {
173 b = inode_bmap(inode, EXT2_IND_BLOCK);
175 if (!(bmap_flags & BMAP_ALLOC))
178 b = inode_bmap(inode, EXT2_IND_BLOCK-1);
179 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
182 inode_bmap(inode, EXT2_IND_BLOCK) = b;
185 retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
186 &blocks_alloc, block, phys_blk);
190 /* Doubly indirect block */
191 block -= addr_per_block;
192 if (block < addr_per_block * addr_per_block) {
193 b = inode_bmap(inode, EXT2_DIND_BLOCK);
195 if (!(bmap_flags & BMAP_ALLOC))
198 b = inode_bmap(inode, EXT2_IND_BLOCK);
199 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
202 inode_bmap(inode, EXT2_DIND_BLOCK) = b;
205 retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
206 &blocks_alloc, block, phys_blk);
210 /* Triply indirect block */
211 block -= addr_per_block * addr_per_block;
212 b = inode_bmap(inode, EXT2_TIND_BLOCK);
214 if (!(bmap_flags & BMAP_ALLOC))
217 b = inode_bmap(inode, EXT2_DIND_BLOCK);
218 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
221 inode_bmap(inode, EXT2_TIND_BLOCK) = b;
224 retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
225 &blocks_alloc, block, phys_blk);
228 ext2fs_free_mem((void **) &buf);
229 if ((retval == 0) && blocks_alloc) {
230 inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
231 retval = ext2fs_write_inode(fs, ino, inode);