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-rw-r--r--e2fslib/bmap.c237
1 files changed, 237 insertions, 0 deletions
diff --git a/e2fslib/bmap.c b/e2fslib/bmap.c
new file mode 100644
index 0000000..25ba695
--- /dev/null
+++ b/e2fslib/bmap.c
@@ -0,0 +1,237 @@
+/*
+ * bmap.c --- logical to physical 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 "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, ext2_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];
+
+#ifdef EXT2FS_ENABLE_SWAPFS
+ if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
+ (fs->flags & EXT2_FLAG_SWAP_BYTES_READ))
+ b = ext2fs_swab32(b);
+#endif
+
+ 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;
+
+#ifdef EXT2FS_ENABLE_SWAPFS
+ if ((fs->flags & EXT2_FLAG_SWAP_BYTES) ||
+ (fs->flags & EXT2_FLAG_SWAP_BYTES_WRITE))
+ ((blk_t *) block_buf)[nr] = ext2fs_swab32(b);
+ else
+#endif
+ ((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;
+ blk_t addr_per_block;
+
+ addr_per_block = (blk_t) 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;
+ blk_t addr_per_block;
+
+ addr_per_block = (blk_t) 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, ext2_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;
+ blk_t 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 = (blk_t) 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;
+}
+
+
+