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-rw-r--r--e2fslib/alloc.c178
1 files changed, 178 insertions, 0 deletions
diff --git a/e2fslib/alloc.c b/e2fslib/alloc.c
new file mode 100644
index 0000000..2de05bc
--- /dev/null
+++ b/e2fslib/alloc.c
@@ -0,0 +1,178 @@
+/*
+ * alloc.c --- allocate new inodes, blocks for ext2fs
+ *
+ * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ *
+ */
+
+#include <stdio.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <time.h>
+#include <string.h>
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * Right now, just search forward from the parent directory's block
+ * group to find the next free inode.
+ *
+ * Should have a special policy for directories.
+ */
+errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir, int mode,
+ ext2fs_inode_bitmap map, ext2_ino_t *ret)
+{
+ ext2_ino_t dir_group = 0;
+ ext2_ino_t i;
+ ext2_ino_t start_inode;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ if (!map)
+ map = fs->inode_map;
+ if (!map)
+ return EXT2_ET_NO_INODE_BITMAP;
+
+ if (dir > 0)
+ dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
+
+ start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
+ if (start_inode < EXT2_FIRST_INODE(fs->super))
+ start_inode = EXT2_FIRST_INODE(fs->super);
+ i = start_inode;
+
+ do {
+ if (!ext2fs_fast_test_inode_bitmap(map, i))
+ break;
+ i++;
+ if (i > fs->super->s_inodes_count)
+ i = EXT2_FIRST_INODE(fs->super);
+ } while (i != start_inode);
+
+ if (ext2fs_test_inode_bitmap(map, i))
+ return EXT2_ET_INODE_ALLOC_FAIL;
+ *ret = i;
+ return 0;
+}
+
+/*
+ * Stupid algorithm --- we now just search forward starting from the
+ * goal. Should put in a smarter one someday....
+ */
+errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
+ ext2fs_block_bitmap map, blk_t *ret)
+{
+ blk_t i;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ if (!map)
+ map = fs->block_map;
+ if (!map)
+ return EXT2_ET_NO_BLOCK_BITMAP;
+ if (!goal || (goal >= fs->super->s_blocks_count))
+ goal = fs->super->s_first_data_block;
+ i = goal;
+ do {
+ if (!ext2fs_fast_test_block_bitmap(map, i)) {
+ *ret = i;
+ return 0;
+ }
+ i++;
+ if (i >= fs->super->s_blocks_count)
+ i = fs->super->s_first_data_block;
+ } while (i != goal);
+ return EXT2_ET_BLOCK_ALLOC_FAIL;
+}
+
+/*
+ * This function zeros out the allocated block, and updates all of the
+ * appropriate filesystem records.
+ */
+errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
+ char *block_buf, blk_t *ret)
+{
+ errcode_t retval;
+ blk_t block;
+ int group;
+ char *buf = 0;
+
+ if (!block_buf) {
+ retval = ext2fs_get_mem(fs->blocksize, (void **) &buf);
+ if (retval)
+ return retval;
+ block_buf = buf;
+ }
+ memset(block_buf, 0, fs->blocksize);
+
+ if (!fs->block_map) {
+ retval = ext2fs_read_block_bitmap(fs);
+ if (retval)
+ goto fail;
+ }
+
+ retval = ext2fs_new_block(fs, goal, 0, &block);
+ if (retval)
+ goto fail;
+
+ retval = io_channel_write_blk(fs->io, block, 1, block_buf);
+ if (retval)
+ goto fail;
+
+ fs->super->s_free_blocks_count--;
+ group = ext2fs_group_of_blk(fs, block);
+ fs->group_desc[group].bg_free_blocks_count--;
+ ext2fs_mark_block_bitmap(fs->block_map, block);
+ ext2fs_mark_super_dirty(fs);
+ ext2fs_mark_bb_dirty(fs);
+ *ret = block;
+ return 0;
+
+fail:
+ if (buf)
+ ext2fs_free_mem((void **) &buf);
+ return retval;
+}
+
+errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
+ int num, ext2fs_block_bitmap map, blk_t *ret)
+{
+ blk_t b = start;
+
+ EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+ if (!map)
+ map = fs->block_map;
+ if (!map)
+ return EXT2_ET_NO_BLOCK_BITMAP;
+ if (!b)
+ b = fs->super->s_first_data_block;
+ if (!finish)
+ finish = start;
+ if (!num)
+ num = 1;
+ do {
+ if (b+num-1 > fs->super->s_blocks_count)
+ b = fs->super->s_first_data_block;
+ if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
+ *ret = b;
+ return 0;
+ }
+ b++;
+ } while (b != finish);
+ return EXT2_ET_BLOCK_ALLOC_FAIL;
+}
+