diff options
Diffstat (limited to 'e2fsprogs/ext2fs/closefs.c')
| -rw-r--r-- | e2fsprogs/ext2fs/closefs.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/closefs.c b/e2fsprogs/ext2fs/closefs.c new file mode 100644 index 000000000..8539a1c25 --- /dev/null +++ b/e2fsprogs/ext2fs/closefs.c @@ -0,0 +1,381 @@ +/* + * closefs.c --- close an ext2 filesystem + * + * 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> + +#include "ext2_fs.h" +#include "ext2fsP.h" + +static int test_root(int a, int b) +{ + if (a == 0) + return 1; + while (1) { + if (a == 1) + return 1; + if (a % b) + return 0; + a = a / b; + } +} + +int ext2fs_bg_has_super(ext2_filsys fs, int group_block) +{ + if (!(fs->super->s_feature_ro_compat & + EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) + return 1; + + if (test_root(group_block, 3) || (test_root(group_block, 5)) || + test_root(group_block, 7)) + return 1; + + return 0; +} + +int ext2fs_super_and_bgd_loc(ext2_filsys fs, + dgrp_t group, + blk_t *ret_super_blk, + blk_t *ret_old_desc_blk, + blk_t *ret_new_desc_blk, + int *ret_meta_bg) +{ + blk_t group_block, super_blk = 0, old_desc_blk = 0, new_desc_blk = 0; + unsigned int meta_bg, meta_bg_size; + int numblocks, has_super; + int old_desc_blocks; + + group_block = fs->super->s_first_data_block + + (group * fs->super->s_blocks_per_group); + + 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; + + if (group == fs->group_desc_count-1) { + numblocks = (fs->super->s_blocks_count - + fs->super->s_first_data_block) % + fs->super->s_blocks_per_group; + if (!numblocks) + numblocks = fs->super->s_blocks_per_group; + } else + numblocks = fs->super->s_blocks_per_group; + + has_super = ext2fs_bg_has_super(fs, group); + + if (has_super) { + super_blk = group_block; + numblocks--; + } + meta_bg_size = (fs->blocksize / sizeof (struct ext2_group_desc)); + meta_bg = group / meta_bg_size; + + if (!(fs->super->s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) || + (meta_bg < fs->super->s_first_meta_bg)) { + if (has_super) { + old_desc_blk = group_block + 1; + numblocks -= old_desc_blocks; + } + } else { + if (((group % meta_bg_size) == 0) || + ((group % meta_bg_size) == 1) || + ((group % meta_bg_size) == (meta_bg_size-1))) { + if (has_super) + has_super = 1; + new_desc_blk = group_block + has_super; + numblocks--; + } + } + + numblocks -= 2 + fs->inode_blocks_per_group; + + if (ret_super_blk) + *ret_super_blk = super_blk; + if (ret_old_desc_blk) + *ret_old_desc_blk = old_desc_blk; + if (ret_new_desc_blk) + *ret_new_desc_blk = new_desc_blk; + if (ret_meta_bg) + *ret_meta_bg = meta_bg; + return (numblocks); +} + + +/* + * This function forces out the primary superblock. We need to only + * write out those fields which we have changed, since if the + * filesystem is mounted, it may have changed some of the other + * fields. + * + * It takes as input a superblock which has already been byte swapped + * (if necessary). + * + */ +static errcode_t write_primary_superblock(ext2_filsys fs, + struct ext2_super_block *super) +{ + __u16 *old_super, *new_super; + int check_idx, write_idx, size; + errcode_t retval; + + if (!fs->io->manager->write_byte || !fs->orig_super) { + io_channel_set_blksize(fs->io, SUPERBLOCK_OFFSET); + retval = io_channel_write_blk(fs->io, 1, -SUPERBLOCK_SIZE, + super); + io_channel_set_blksize(fs->io, fs->blocksize); + return retval; + } + + old_super = (__u16 *) fs->orig_super; + new_super = (__u16 *) super; + + for (check_idx = 0; check_idx < SUPERBLOCK_SIZE/2; check_idx++) { + if (old_super[check_idx] == new_super[check_idx]) + continue; + write_idx = check_idx; + for (check_idx++; check_idx < SUPERBLOCK_SIZE/2; check_idx++) + if (old_super[check_idx] == new_super[check_idx]) + break; + size = 2 * (check_idx - write_idx); +#if 0 + printf("Writing %d bytes starting at %d\n", + size, write_idx*2); +#endif + retval = io_channel_write_byte(fs->io, + SUPERBLOCK_OFFSET + (2 * write_idx), size, + new_super + write_idx); + if (retval) + return retval; + } + memcpy(fs->orig_super, super, SUPERBLOCK_SIZE); + return 0; +} + + +/* + * Updates the revision to EXT2_DYNAMIC_REV + */ +void ext2fs_update_dynamic_rev(ext2_filsys fs) +{ + struct ext2_super_block *sb = fs->super; + + if (sb->s_rev_level > EXT2_GOOD_OLD_REV) + return; + + sb->s_rev_level = EXT2_DYNAMIC_REV; + sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; + sb->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE; + /* s_uuid is handled by e2fsck already */ + /* other fields should be left alone */ +} + +static errcode_t write_backup_super(ext2_filsys fs, dgrp_t group, + blk_t group_block, + struct ext2_super_block *super_shadow) +{ + dgrp_t sgrp = group; + + if (sgrp > ((1 << 16) - 1)) + sgrp = (1 << 16) - 1; +#ifdef EXT2FS_ENABLE_SWAPFS + if (fs->flags & EXT2_FLAG_SWAP_BYTES) + super_shadow->s_block_group_nr = ext2fs_swab16(sgrp); + else +#endif + fs->super->s_block_group_nr = sgrp; + + return io_channel_write_blk(fs->io, group_block, -SUPERBLOCK_SIZE, + super_shadow); +} + + +errcode_t ext2fs_flush(ext2_filsys fs) +{ + dgrp_t i,j; + blk_t group_block; + errcode_t retval; + unsigned long fs_state; + struct ext2_super_block *super_shadow = 0; + struct ext2_group_desc *group_shadow = 0; + struct ext2_group_desc *s, *t; + char *group_ptr; + int old_desc_blocks; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + fs_state = fs->super->s_state; + + fs->super->s_wtime = time(NULL); + fs->super->s_block_group_nr = 0; +#ifdef EXT2FS_ENABLE_SWAPFS + if (fs->flags & EXT2_FLAG_SWAP_BYTES) { + retval = EXT2_ET_NO_MEMORY; + retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super_shadow); + if (retval) + goto errout; + retval = ext2fs_get_mem((size_t)(fs->blocksize * + fs->desc_blocks), + &group_shadow); + if (retval) + goto errout; + memset(group_shadow, 0, (size_t) fs->blocksize * + fs->desc_blocks); + + /* swap the group descriptors */ + for (j=0, s=fs->group_desc, t=group_shadow; + j < fs->group_desc_count; j++, t++, s++) { + *t = *s; + ext2fs_swap_group_desc(t); + } + } else { + super_shadow = fs->super; + group_shadow = fs->group_desc; + } +#else + super_shadow = fs->super; + group_shadow = fs->group_desc; +#endif + + /* + * If this is an external journal device, don't write out the + * block group descriptors or any of the backup superblocks + */ + if (fs->super->s_feature_incompat & + EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) + goto write_primary_superblock_only; + + /* + * Set the state of the FS to be non-valid. (The state has + * already been backed up earlier, and will be restored after + * we write out the backup superblocks.) + */ + fs->super->s_state &= ~EXT2_VALID_FS; +#ifdef EXT2FS_ENABLE_SWAPFS + if (fs->flags & EXT2_FLAG_SWAP_BYTES) { + *super_shadow = *fs->super; + ext2fs_swap_super(super_shadow); + } +#endif + + /* + * Write out the master group descriptors, and the backup + * superblocks and group descriptors. + */ + group_block = fs->super->s_first_data_block; + group_ptr = (char *) group_shadow; + 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; + + for (i = 0; i < fs->group_desc_count; i++) { + blk_t super_blk, old_desc_blk, new_desc_blk; + int meta_bg; + + ext2fs_super_and_bgd_loc(fs, i, &super_blk, &old_desc_blk, + &new_desc_blk, &meta_bg); + + if (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) &&i && super_blk) { + retval = write_backup_super(fs, i, super_blk, + super_shadow); + if (retval) + goto errout; + } + if (fs->flags & EXT2_FLAG_SUPER_ONLY) + continue; + if ((old_desc_blk) && + (!(fs->flags & EXT2_FLAG_MASTER_SB_ONLY) || (i == 0))) { + retval = io_channel_write_blk(fs->io, + old_desc_blk, old_desc_blocks, group_ptr); + if (retval) + goto errout; + } + if (new_desc_blk) { + retval = io_channel_write_blk(fs->io, new_desc_blk, + 1, group_ptr + (meta_bg*fs->blocksize)); + if (retval) + goto errout; + } + } + fs->super->s_block_group_nr = 0; + fs->super->s_state = fs_state; +#ifdef EXT2FS_ENABLE_SWAPFS + if (fs->flags & EXT2_FLAG_SWAP_BYTES) { + *super_shadow = *fs->super; + ext2fs_swap_super(super_shadow); + } +#endif + + /* + * If the write_bitmaps() function is present, call it to + * flush the bitmaps. This is done this way so that a simple + * program that doesn't mess with the bitmaps doesn't need to + * drag in the bitmaps.c code. + */ + if (fs->write_bitmaps) { + retval = fs->write_bitmaps(fs); + if (retval) + goto errout; + } + +write_primary_superblock_only: + /* + * Write out master superblock. This has to be done + * separately, since it is located at a fixed location + * (SUPERBLOCK_OFFSET). We flush all other pending changes + * out to disk first, just to avoid a race condition with an + * insy-tinsy window.... + */ + retval = io_channel_flush(fs->io); + retval = write_primary_superblock(fs, super_shadow); + if (retval) + goto errout; + + fs->flags &= ~EXT2_FLAG_DIRTY; + + retval = io_channel_flush(fs->io); +errout: + fs->super->s_state = fs_state; + if (fs->flags & EXT2_FLAG_SWAP_BYTES) { + if (super_shadow) + ext2fs_free_mem(&super_shadow); + if (group_shadow) + ext2fs_free_mem(&group_shadow); + } + return retval; +} + +errcode_t ext2fs_close(ext2_filsys fs) +{ + errcode_t retval; + + EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); + + if (fs->flags & EXT2_FLAG_DIRTY) { + retval = ext2fs_flush(fs); + if (retval) + return retval; + } + if (fs->write_bitmaps) { + retval = fs->write_bitmaps(fs); + if (retval) + return retval; + } + ext2fs_free(fs); + return 0; +} + |