[Ocfs2-devel] [PATCH v2] ocfs2: fix non-auto defrag path not working issue

[Joseph Qi]

On 2/20/23 1:05 PM, Heming Zhao wrote:
> This fixes three issues on move extents ioctl without auto defrag:
> 
> a) In ocfs2_find_victim_alloc_group(), we have to convert bits to block
> first in case of global bitmap.
> b) In ocfs2_probe_alloc_group(), when finding enough bits in block group
> bitmap, we have to back off move_len to start pos as well, otherwise it
> may corrupt filesystem.
> c) In ocfs2_ioctl_move_extents(), set me_threshold both for non-auto and
> auto defrag paths. Otherwise it will set move_max_hop to 0 and finally
> cause unexpectedly ENOSPC error.
> 
> Currently there is no tools triggering the above issues since
> defragfs.ocfs2 enables auto defrag by default. Test with manually
> changing defragfs.ocfs2 to run non auto defrag path.
> 
> Signed-off-by: Heming Zhao <heming.zhao at suse.com>

Reviewed-by: Joseph Qi <joseph.qi at linux.alibaba.com>
> ---
> v2: revise commit log under review comment
> 
> ---
>  fs/ocfs2/move_extents.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ocfs2/move_extents.c b/fs/ocfs2/move_extents.c
> index 6251748c695b..b1e32ec4a9d4 100644
> --- a/fs/ocfs2/move_extents.c
> +++ b/fs/ocfs2/move_extents.c
> @@ -434,7 +434,7 @@ static int ocfs2_find_victim_alloc_group(struct inode *inode,
>  			bg = (struct ocfs2_group_desc *)gd_bh->b_data;
>  
>  			if (vict_blkno < (le64_to_cpu(bg->bg_blkno) +
> -						le16_to_cpu(bg->bg_bits))) {
> +						(le16_to_cpu(bg->bg_bits) << bits_per_unit))) {
>  
>  				*ret_bh = gd_bh;
>  				*vict_bit = (vict_blkno - blkno) >>
> @@ -549,6 +549,7 @@ static void ocfs2_probe_alloc_group(struct inode *inode, struct buffer_head *bh,
>  			last_free_bits++;
>  
>  		if (last_free_bits == move_len) {
> +			i -= move_len;
>  			*goal_bit = i;
>  			*phys_cpos = base_cpos + i;
>  			break;
> @@ -1020,18 +1021,19 @@ int ocfs2_ioctl_move_extents(struct file *filp, void __user *argp)
>  
>  	context->range = ⦥
>  
> +	/*
> +	 * ok, the default theshold for the defragmentation
> +	 * is 1M, since our maximum clustersize was 1M also.
> +	 * any thought?
> +	 */
> +	if (!range.me_threshold)
> +		range.me_threshold = 1024 * 1024;
> +
> +	if (range.me_threshold > i_size_read(inode))
> +		range.me_threshold = i_size_read(inode);
> +
>  	if (range.me_flags & OCFS2_MOVE_EXT_FL_AUTO_DEFRAG) {
>  		context->auto_defrag = 1;
> -		/*
> -		 * ok, the default theshold for the defragmentation
> -		 * is 1M, since our maximum clustersize was 1M also.
> -		 * any thought?
> -		 */
> -		if (!range.me_threshold)
> -			range.me_threshold = 1024 * 1024;
> -
> -		if (range.me_threshold > i_size_read(inode))
> -			range.me_threshold = i_size_read(inode);
>  
>  		if (range.me_flags & OCFS2_MOVE_EXT_FL_PART_DEFRAG)
>  			context->partial = 1;