Following process may lead to fs corruption: 1. ext4_create(dir/foo) ext4_add_nondir ext4_add_entry ext4_dx_add_entry a. add_dirent_to_buf ext4_mark_inode_dirty ext4_handle_dirty_metadata // dir inode bh is recorded into journal b. ext4_append // dx_get_count(entries) == dx_get_limit(entries) ext4_bread(EXT4_GET_BLOCKS_CREATE) ext4_getblk ext4_map_blocks ext4_ext_map_blocks ext4_mb_new_blocks dquot_alloc_block dquot_alloc_space_nodirty inode_add_bytes // update dir's i_blocks ext4_ext_insert_extent ext4_ext_dirty // record extent bh into journal ext4_handle_dirty_metadata(bh) // record new block into journal inode->i_size += inode->i_sb->s_blocksize // new size(in mem) c. ext4_handle_dirty_dx_node(bh2) // record dir's new block(dx_node) into journal d. ext4_handle_dirty_dx_node((frame - 1)->bh) e. ext4_handle_dirty_dx_node(frame->bh) f. do_split // ret err! g. add_dirent_to_buf ext4_mark_inode_dirty(dir) // udpate raw_inode on disk(skipped) 2. fsck -a /dev/sdb drop last block(dx_node) which beyonds dir's i_size. /dev/sdb: recovering journal /dev/sdb contains a file system with errors, check forced. /dev/sdb: Inode 12, end of extent exceeds allowed value (logical block 128, physical block 3938, len 1) 3. fsck -fn /dev/sdb dx_node->entry[i].blk > dir->i_size Pass 2: Checking directory structure Problem in HTREE directory inode 12 (/dir): bad block number 128. Clear HTree index? no Problem in HTREE directory inode 12: block #3 has invalid depth (2) Problem in HTREE directory inode 12: block #3 has bad max hash Problem in HTREE directory inode 12: block #3 not referenced
Reproducer: 1. Apply diff and compile kernel 2. ./test.sh，Stop machine after seeing kernel message "wait shutdown" 3. reboot，fsck -fa /dev/sdb fsck from util-linux 2.38 /dev/sdb: recovering journal /dev/sdb: Inode 12, end of extent exceeds allowed value (logical block 128, physical block 3819, len 1) /dev/sdb: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY. (i.e., without -a or -p options) 4. fsck -fn /dev/sdb fsck from util-linux 2.38 e2fsck 1.43.4 (31-Jan-2017) Pass 1: Checking inodes, blocks, and sizes Inode 12, end of extent exceeds allowed value (logical block 128, physical block 3819, len 1) Clear? no Inode 12, i_blocks is 262, should be 260. Fix? no Pass 2: Checking directory structure Problem in HTREE directory inode 12 (/dir): bad block number 128. Clear HTree index? no Problem in HTREE directory inode 12: block #2 has invalid depth (2) Problem in HTREE directory inode 12: block #2 has bad max hash Problem in HTREE directory inode 12: block #2 not referenced
Created attachment 301777 [details] diff
Created attachment 301778 [details] test.sh