We rely on a nasty hack to adjust the free block count where we pass signed value into ext2fs_free_blocks_count_add(), which takes an 64-bit unsigned value, and relies on overflow and C's signed->unsigned semantics to do the subtraction. This works, so long as a 64-bit signed value is used. Unfortunately, ext2fs_block_alloc_stats2() and ext2fs_block_alloc_stats_range(), this is not true, so on a 64-bit file system, the free blocks accounting can get screwed up. A simple way to demonstrate the problem is: mke2fs -F -t ext4 -O 64bit /tmp/foo.img 1M e2fsck -fy /tmp/foo.img ... which will result in the following e2fsck complaint: Pass 5: Checking group summary information Free blocks count wrong (4294968278, counted=982). Fix? yes Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> --- lib/ext2fs/alloc_stats.c | 4 ++-- tests/m_64bit_flexbg/expect.1 | 55 +++++++++++++++++++++++++++++++++++++++++++ tests/m_64bit_flexbg/script | 4 ++++ 3 files changed, 61 insertions(+), 2 deletions(-) create mode 100644 tests/m_64bit_flexbg/expect.1 create mode 100644 tests/m_64bit_flexbg/script diff --git a/lib/ext2fs/alloc_stats.c b/lib/ext2fs/alloc_stats.c index 1f58e00..a449dc3 100644 --- a/lib/ext2fs/alloc_stats.c +++ b/lib/ext2fs/alloc_stats.c @@ -79,7 +79,7 @@ void ext2fs_block_alloc_stats2(ext2_filsys fs, blk64_t blk, int inuse) ext2fs_group_desc_csum_set(fs, group); ext2fs_free_blocks_count_add(fs->super, - -inuse * EXT2FS_CLUSTER_RATIO(fs)); + -inuse * (blk64_t) EXT2FS_CLUSTER_RATIO(fs)); ext2fs_mark_super_dirty(fs); ext2fs_mark_bb_dirty(fs); if (fs->block_alloc_stats) @@ -140,7 +140,7 @@ void ext2fs_block_alloc_stats_range(ext2_filsys fs, blk64_t blk, inuse*n/EXT2FS_CLUSTER_RATIO(fs)); ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT); ext2fs_group_desc_csum_set(fs, group); - ext2fs_free_blocks_count_add(fs->super, -inuse * n); + ext2fs_free_blocks_count_add(fs->super, -inuse * (blk64_t) n); blk += n; num -= n; } diff --git a/tests/m_64bit_flexbg/expect.1 b/tests/m_64bit_flexbg/expect.1 new file mode 100644 index 0000000..3635318 --- /dev/null +++ b/tests/m_64bit_flexbg/expect.1 @@ -0,0 +1,55 @@ +Creating filesystem with 1024 1k blocks and 128 inodes + +Allocating group tables: done +Writing inode tables: done +Writing superblocks and filesystem accounting information: done + +Filesystem features: ext_attr resize_inode dir_index filetype extent 64bit flex_bg sparse_super +Pass 1: Checking inodes, blocks, and sizes +Pass 2: Checking directory structure +Pass 3: Checking directory connectivity +Pass 4: Checking reference counts +Pass 5: Checking group summary information +test_filesys: 11/128 files (0.0% non-contiguous), 42/1024 blocks +Exit status is 0 +Filesystem volume name: <none> +Last mounted on: <not available> +Filesystem magic number: 0xEF53 +Filesystem revision #: 1 (dynamic) +Filesystem features: ext_attr resize_inode dir_index filetype extent 64bit flex_bg sparse_super +Default mount options: (none) +Filesystem state: clean +Errors behavior: Continue +Filesystem OS type: Linux +Inode count: 128 +Block count: 1024 +Reserved block count: 51 +Free blocks: 982 +Free inodes: 117 +First block: 1 +Block size: 1024 +Fragment size: 1024 +Group descriptor size: 64 +Reserved GDT blocks: 7 +Blocks per group: 8192 +Fragments per group: 8192 +Inodes per group: 128 +Inode blocks per group: 16 +Flex block group size: 16 +Mount count: 0 +Check interval: 15552000 (6 months) +Reserved blocks uid: 0 +Reserved blocks gid: 0 +First inode: 11 +Inode size: 128 +Default directory hash: half_md4 + + +Group 0: (Blocks 1-1023) + Primary superblock at 1, Group descriptors at 2-2 + Reserved GDT blocks at 3-9 + Block bitmap at 10 (+9), Inode bitmap at 26 (+25) + Inode table at 42-57 (+41) + 982 free blocks, 117 free inodes, 2 directories + Free blocks: 24-25, 28-41, 58-1023 + Free inodes: 12-128 diff --git a/tests/m_64bit_flexbg/script b/tests/m_64bit_flexbg/script new file mode 100644 index 0000000..98684e4 --- /dev/null +++ b/tests/m_64bit_flexbg/script @@ -0,0 +1,4 @@ +DESCRIPTION="mkfs with 64bit and flex_bg" +FS_SIZE=1M +MKE2FS_OPTS="-O 64bit,extents,flex_bg" +. $cmd_dir/run_mke2fs -- 2.0.0 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
