diff options
Diffstat (limited to 'fs/ext4/format/alloc.c')
| -rwxr-xr-x | fs/ext4/format/alloc.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/fs/ext4/format/alloc.c b/fs/ext4/format/alloc.c new file mode 100755 index 0000000..8cfd57d --- /dev/null +++ b/fs/ext4/format/alloc.c @@ -0,0 +1,274 @@ +/* + * 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 Library + * General Public License, version 2. + * %End-Header% + */ + +#include <common.h> +//#include <ext_common.h> +//#include <ext4fs.h> +#include <malloc.h> +#include <stddef.h> +#include <linux/stat.h> +#include <linux/time.h> + + +#include "ext2_fs.h" +#include "ext2fs.h" + +/* + * Check for uninit block bitmaps and deal with them appropriately + */ +static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map, + dgrp_t group) +{ + blk_t i; + blk_t blk, super_blk, old_desc_blk, new_desc_blk; + int old_desc_blocks; + + if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || + !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT)) + return; + + blk = (group * fs->super->s_blocks_per_group) + + fs->super->s_first_data_block; + + ext2fs_super_and_bgd_loc(fs, group, &super_blk, + &old_desc_blk, &new_desc_blk, 0); + + if (fs->super->s_feature_incompat & + EXT2_FEATURE_INCOMPAT_META_BG) + old_desc_blocks = fs->super->s_first_meta_bg; + else + old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks; + + for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) { + if ((blk == super_blk) || + (old_desc_blk && old_desc_blocks && + (blk >= old_desc_blk) && + (blk < old_desc_blk + old_desc_blocks)) || + (new_desc_blk && (blk == new_desc_blk)) || + (blk == fs->group_desc[group].bg_block_bitmap) || + (blk == fs->group_desc[group].bg_inode_bitmap) || + (blk >= fs->group_desc[group].bg_inode_table && + (blk < fs->group_desc[group].bg_inode_table + + fs->inode_blocks_per_group))) + ext2fs_fast_mark_block_bitmap(map, blk); + else + ext2fs_fast_unmark_block_bitmap(map, blk); + } + fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT; + ext2fs_group_desc_csum_set(fs, group); +} + +/* + * Check for uninit inode bitmaps and deal with them appropriately + */ +static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map, + dgrp_t group) +{ + ext2_ino_t i, ino; + + if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super, + EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) || + !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT)) + return; + + ino = (group * fs->super->s_inodes_per_group) + 1; + for (i=0; i < fs->super->s_inodes_per_group; i++, ino++) + ext2fs_fast_unmark_inode_bitmap(map, ino); + + fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT; + check_block_uninit(fs, fs->block_map, group); +} + +/* + * 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); + if (start_inode > fs->super->s_inodes_count) + return EXT2_ET_INODE_ALLOC_FAIL; + i = start_inode; + + do { + if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0) + check_inode_uninit(fs, map, (i - 1) / + EXT2_INODES_PER_GROUP(fs->super)); + + 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; + check_block_uninit(fs, map, + (i - fs->super->s_first_data_block) / + EXT2_BLOCKS_PER_GROUP(fs->super)); + do { + if (((i - fs->super->s_first_data_block) % + EXT2_BLOCKS_PER_GROUP(fs->super)) == 0) + check_block_uninit(fs, map, + (i - fs->super->s_first_data_block) / + EXT2_BLOCKS_PER_GROUP(fs->super)); + + 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->get_alloc_block) { + blk64_t new; + + retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new); + if (retval) + goto fail; + block = (blk_t) new; + } else { + 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; + +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; +} + +void ext2fs_set_alloc_block_callback(ext2_filsys fs, + errcode_t (*func)(ext2_filsys fs, + blk64_t goal, + blk64_t *ret), + errcode_t (**old)(ext2_filsys fs, + blk64_t goal, + blk64_t *ret)) +{ + if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS) + return; + + if (old) + *old = fs->get_alloc_block; + + fs->get_alloc_block = func; +} |