Looks good to me.
Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
On Wed, Jan 5, 2022 at 6:45 PM Xin Yin <yinxin.x@xxxxxxxxxxxxx> wrote:
>
> for now in ext4_mb_new_blocks_simple, if we found a block which
> should be excluded then will switch to next group, this may
> probably cause 'group' run out of range.
>
> change to check next block in the same group when get a block should
> be excluded. Also change the searche range to EXT4_CLUSTERS_PER_GROUP
> and add error checking.
>
> Signed-off-by: Xin Yin <yinxin.x@xxxxxxxxxxxxx>
> ---
> fs/ext4/mballoc.c | 26 +++++++++++++++++---------
> 1 file changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 215b7068f548..31a00b473f3e 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -5757,7 +5757,8 @@ static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
> struct super_block *sb = ar->inode->i_sb;
> ext4_group_t group;
> ext4_grpblk_t blkoff;
> - int i = sb->s_blocksize;
> + ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
> + ext4_grpblk_t i = 0;
> ext4_fsblk_t goal, block;
> struct ext4_super_block *es = EXT4_SB(sb)->s_es;
>
> @@ -5779,19 +5780,26 @@ static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
> ext4_get_group_no_and_offset(sb,
> max(ext4_group_first_block_no(sb, group), goal),
> NULL, &blkoff);
> - i = mb_find_next_zero_bit(bitmap_bh->b_data, sb->s_blocksize,
> + while (1) {
> + i = mb_find_next_zero_bit(bitmap_bh->b_data, max,
> blkoff);
> + if (i >= max)
> + break;
> + if (ext4_fc_replay_check_excluded(sb,
> + ext4_group_first_block_no(sb, group) + i)) {
> + blkoff = i + 1;
> + } else
> + break;
> + }
> brelse(bitmap_bh);
> - if (i >= sb->s_blocksize)
> - continue;
> - if (ext4_fc_replay_check_excluded(sb,
> - ext4_group_first_block_no(sb, group) + i))
> - continue;
> - break;
> + if (i < max)
> + break;
> }
>
> - if (group >= ext4_get_groups_count(sb) && i >= sb->s_blocksize)
> + if (group >= ext4_get_groups_count(sb) || i >= max) {
> + *errp = -ENOSPC;
> return 0;
> + }
>
> block = ext4_group_first_block_no(sb, group) + i;
> ext4_mb_mark_bb(sb, block, 1, 1);
> --
> 2.20.1
>
