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);
32 #define inode_bmap(inode, nr) ((inode)->i_block[(nr)])
34 static _BMAP_INLINE_ errcode_t block_ind_bmap(ext2_filsys fs, int flags,
35 blk_t ind, char *block_buf,
37 blk_t nr, blk_t *ret_blk)
44 return EXT2_ET_SET_BMAP_NO_IND;
48 retval = io_channel_read_blk(fs->io, ind, 1, block_buf);
52 if (flags & BMAP_SET) {
54 #ifdef EXT2FS_ENABLE_SWAPFS
55 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
56 (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
59 ((blk_t *) block_buf)[nr] = b;
60 return io_channel_write_blk(fs->io, ind, 1, block_buf);
63 b = ((blk_t *) block_buf)[nr];
65 #ifdef EXT2FS_ENABLE_SWAPFS
66 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
67 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
71 if (!b && (flags & BMAP_ALLOC)) {
72 b = nr ? ((blk_t *) block_buf)[nr-1] : 0;
73 retval = ext2fs_alloc_block(fs, b,
74 block_buf + fs->blocksize, &b);
78 #ifdef EXT2FS_ENABLE_SWAPFS
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);
84 ((blk_t *) block_buf)[nr] = b;
86 retval = io_channel_write_blk(fs->io, ind, 1, block_buf);
97 static _BMAP_INLINE_ errcode_t block_dind_bmap(ext2_filsys fs, int flags,
98 blk_t dind, char *block_buf,
100 blk_t nr, blk_t *ret_blk)
104 blk_t addr_per_block;
106 addr_per_block = (blk_t) fs->blocksize >> 2;
108 retval = block_ind_bmap(fs, flags & ~BMAP_SET, dind, block_buf,
109 blocks_alloc, nr / addr_per_block, &b);
112 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
113 nr % addr_per_block, ret_blk);
117 static _BMAP_INLINE_ errcode_t block_tind_bmap(ext2_filsys fs, int flags,
118 blk_t tind, char *block_buf,
120 blk_t nr, blk_t *ret_blk)
124 blk_t addr_per_block;
126 addr_per_block = (blk_t) fs->blocksize >> 2;
128 retval = block_dind_bmap(fs, flags & ~BMAP_SET, tind, block_buf,
129 blocks_alloc, nr / addr_per_block, &b);
132 retval = block_ind_bmap(fs, flags, b, block_buf, blocks_alloc,
133 nr % addr_per_block, ret_blk);
137 errcode_t ext2fs_bmap(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
138 char *block_buf, int bmap_flags, blk_t block,
141 struct ext2_inode inode_buf;
142 blk_t addr_per_block;
145 errcode_t retval = 0;
146 int blocks_alloc = 0, inode_dirty = 0;
148 if (!(bmap_flags & BMAP_SET))
151 /* Read inode structure if necessary */
153 retval = ext2fs_read_inode(fs, ino, &inode_buf);
158 addr_per_block = (blk_t) fs->blocksize >> 2;
161 retval = ext2fs_get_mem(fs->blocksize * 2, &buf);
167 if (block < EXT2_NDIR_BLOCKS) {
168 if (bmap_flags & BMAP_SET) {
170 #ifdef EXT2FS_ENABLE_SWAPFS
171 if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
172 (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
173 b = ext2fs_swab32(b);
175 inode_bmap(inode, block) = b;
180 *phys_blk = inode_bmap(inode, block);
181 b = block ? inode_bmap(inode, block-1) : 0;
183 if ((*phys_blk == 0) && (bmap_flags & BMAP_ALLOC)) {
184 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
187 inode_bmap(inode, block) = b;
195 block -= EXT2_NDIR_BLOCKS;
196 if (block < addr_per_block) {
197 b = inode_bmap(inode, EXT2_IND_BLOCK);
199 if (!(bmap_flags & BMAP_ALLOC)) {
200 if (bmap_flags & BMAP_SET)
201 retval = EXT2_ET_SET_BMAP_NO_IND;
205 b = inode_bmap(inode, EXT2_IND_BLOCK-1);
206 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
209 inode_bmap(inode, EXT2_IND_BLOCK) = b;
212 retval = block_ind_bmap(fs, bmap_flags, b, block_buf,
213 &blocks_alloc, block, phys_blk);
217 /* Doubly indirect block */
218 block -= addr_per_block;
219 if (block < addr_per_block * addr_per_block) {
220 b = inode_bmap(inode, EXT2_DIND_BLOCK);
222 if (!(bmap_flags & BMAP_ALLOC)) {
223 if (bmap_flags & BMAP_SET)
224 retval = EXT2_ET_SET_BMAP_NO_IND;
228 b = inode_bmap(inode, EXT2_IND_BLOCK);
229 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
232 inode_bmap(inode, EXT2_DIND_BLOCK) = b;
235 retval = block_dind_bmap(fs, bmap_flags, b, block_buf,
236 &blocks_alloc, block, phys_blk);
240 /* Triply indirect block */
241 block -= addr_per_block * addr_per_block;
242 b = inode_bmap(inode, EXT2_TIND_BLOCK);
244 if (!(bmap_flags & BMAP_ALLOC)) {
245 if (bmap_flags & BMAP_SET)
246 retval = EXT2_ET_SET_BMAP_NO_IND;
250 b = inode_bmap(inode, EXT2_DIND_BLOCK);
251 retval = ext2fs_alloc_block(fs, b, block_buf, &b);
254 inode_bmap(inode, EXT2_TIND_BLOCK) = b;
257 retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
258 &blocks_alloc, block, phys_blk);
261 ext2fs_free_mem(&buf);
262 if ((retval == 0) && (blocks_alloc || inode_dirty)) {
263 inode->i_blocks += (blocks_alloc * fs->blocksize) / 512;
264 retval = ext2fs_write_inode(fs, ino, inode);