diff options
Diffstat (limited to 'e2fsprogs/ext2fs/alloc.c')
| -rw-r--r-- | e2fsprogs/ext2fs/alloc.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/alloc.c b/e2fsprogs/ext2fs/alloc.c new file mode 100644 index 0000000..7385123 --- /dev/null +++ b/e2fsprogs/ext2fs/alloc.c @@ -0,0 +1,173 @@ +/* + * 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_ATTR((unused)), + 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; + char *buf = 0; + + if (!block_buf) { + retval = ext2fs_get_mem(fs->blocksize, &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; + + ext2fs_block_alloc_stats(fs, block, +1); + *ret = block; + return 0; + +fail: + if (buf) + ext2fs_free_mem(&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; +} + |