On Tue, Mar 31, 2020 at 12:50:16PM +0200, Jan Kara wrote:
> We do not want to create initialized extents beyond end of file because
> for e2fsck it is impossible to distinguish them from a case of corrupted
> file size / extent tree and so it complains like:
>
> Inode 12, i_size is 147456, should be 163840. Fix? no
>
> Code in ext4_ext_convert_to_initialized() and
> ext4_split_convert_extents() try to make sure it does not create
> initialized extents beyond inode size however they check against
> inode->i_size which is wrong. They should instead check against
> EXT4_I(inode)->i_disksize which is the current inode size on disk.
> That's what e2fsck is going to see in case of crash before all dirty
> data is written. This bug manifests as generic/456 test failure (with
> recent enough fstests where fsx got fixed to properly pass
> FALLOC_KEEP_SIZE_FL flags to the kernel) when run with dioread_lock
> mount option.
Makes sense, thanks.
Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx>
-Lukas
>
> CC: stable@xxxxxxxxxxxxxxx
> Fixes: 21ca087a3891 ("ext4: Do not zero out uninitialized extents beyond i_size")
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> fs/ext4/extents.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 954013d6076b..c5e190fd4589 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3532,8 +3532,8 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
> (unsigned long long)map->m_lblk, map_len);
>
> sbi = EXT4_SB(inode->i_sb);
> - eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
> - inode->i_sb->s_blocksize_bits;
> + eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
> + >> inode->i_sb->s_blocksize_bits;
> if (eof_block < map->m_lblk + map_len)
> eof_block = map->m_lblk + map_len;
>
> @@ -3785,8 +3785,8 @@ static int ext4_split_convert_extents(handle_t *handle,
> __func__, inode->i_ino,
> (unsigned long long)map->m_lblk, map->m_len);
>
> - eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
> - inode->i_sb->s_blocksize_bits;
> + eof_block = (EXT4_I(inode)->i_disksize + inode->i_sb->s_blocksize - 1)
> + >> inode->i_sb->s_blocksize_bits;
> if (eof_block < map->m_lblk + map->m_len)
> eof_block = map->m_lblk + map->m_len;
> /*
> --
> 2.16.4
>
