Re: [PATCH v6 08/11] ext4: call ext4_mb_mark_context in ext4_group_add_blocks()

[IBM]

Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> writes:

> Call ext4_mb_mark_context in ext4_group_add_blocks() to remove repeat code.
>
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
> ---
>  fs/ext4/mballoc.c | 84 +++++++----------------------------------------
>  1 file changed, 12 insertions(+), 72 deletions(-)

I think same comments (like in patch-5 & patch-6) hold for this and the previous patch as well where
we are seperating out bitmap free and buddy free from ext4_group_add_blocks. 

-ritesh


>
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index bb08a71a6e61..fdffa3b40bcd 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -6681,25 +6681,22 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
>  int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
>  			 ext4_fsblk_t block, unsigned long count)
>  {
> -	struct buffer_head *bitmap_bh = NULL;
> -	struct buffer_head *gd_bh;
> +	struct ext4_mark_context mc;
>  	ext4_group_t block_group;
>  	ext4_grpblk_t bit;
> -	unsigned int i;
> -	struct ext4_group_desc *desc;
>  	struct ext4_sb_info *sbi = EXT4_SB(sb);
>  	struct ext4_buddy e4b;
> -	int err = 0, ret, free_clusters_count;
> -	ext4_grpblk_t clusters_freed;
> +	int err = 0;
>  	ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
>  	ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
>  	unsigned long cluster_count = last_cluster - first_cluster + 1;
>  
>  	ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
>  
> -	if (count == 0)
> +	if (cluster_count == 0)
>  		return 0;
>  
> +	ext4_mb_prepare_mark_context(&mc, handle, sb, 0);
>  	ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
>  	/*
>  	 * Check to see if we are freeing blocks across a group
> @@ -6712,19 +6709,6 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
>  		goto error_return;
>  	}
>  
> -	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
> -	if (IS_ERR(bitmap_bh)) {
> -		err = PTR_ERR(bitmap_bh);
> -		bitmap_bh = NULL;
> -		goto error_return;
> -	}
> -
> -	desc = ext4_get_group_desc(sb, block_group, &gd_bh);
> -	if (!desc) {
> -		err = -EIO;
> -		goto error_return;
> -	}
> -
>  	if (!ext4_sb_block_valid(sb, NULL, block, count)) {
>  		ext4_error(sb, "Adding blocks in system zones - "
>  			   "Block = %llu, count = %lu",
> @@ -6733,74 +6717,30 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
>  		goto error_return;
>  	}
>  
> -	BUFFER_TRACE(bitmap_bh, "getting write access");
> -	err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
> -					    EXT4_JTR_NONE);
> +	err = ext4_mb_load_buddy(sb, block_group, &e4b);
>  	if (err)
>  		goto error_return;
>  
> -	/*
> -	 * We are about to modify some metadata.  Call the journal APIs
> -	 * to unshare ->b_data if a currently-committing transaction is
> -	 * using it
> -	 */
> -	BUFFER_TRACE(gd_bh, "get_write_access");
> -	err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
> -	if (err)
> +	err = ext4_mb_mark_context(&mc, block_group, bit, cluster_count,
> +				   EXT4_MB_BITMAP_MARKED_CHECK);
> +	if (err && mc.changed == 0) {
> +		ext4_mb_unload_buddy(&e4b);
>  		goto error_return;
> -
> -	for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
> -		BUFFER_TRACE(bitmap_bh, "clear bit");
> -		if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
> -			ext4_error(sb, "bit already cleared for block %llu",
> -				   (ext4_fsblk_t)(block + i));
> -			BUFFER_TRACE(bitmap_bh, "bit already cleared");
> -		} else {
> -			clusters_freed++;
> -		}
>  	}
>  
> -	err = ext4_mb_load_buddy(sb, block_group, &e4b);
> -	if (err)
> -		goto error_return;
> -
> -	ext4_lock_group(sb, block_group);
> -	mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
> -	free_clusters_count = clusters_freed +
> -		ext4_free_group_clusters(sb, desc);
> -	ext4_free_group_clusters_set(sb, desc, free_clusters_count);
> -	ext4_block_bitmap_csum_set(sb, desc, bitmap_bh);
> -	ext4_group_desc_csum_set(sb, block_group, desc);
> -	ext4_unlock_group(sb, block_group);
> +	if (mc.changed != cluster_count)
> +		ext4_error(sb, "bit already cleared in group %u", block_group);
>  
>  	ext4_lock_group(sb, block_group);
>  	mb_free_blocks(NULL, &e4b, bit, cluster_count);
>  	ext4_unlock_group(sb, block_group);
>  
>  	percpu_counter_add(&sbi->s_freeclusters_counter,
> -			   clusters_freed);
> -
> -	if (sbi->s_log_groups_per_flex) {
> -		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
> -		atomic64_add(clusters_freed,
> -			     &sbi_array_rcu_deref(sbi, s_flex_groups,
> -						  flex_group)->free_clusters);
> -	}
> +			   mc.changed);
>  
>  	ext4_mb_unload_buddy(&e4b);
>  
> -	/* We dirtied the bitmap block */
> -	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
> -	err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
> -
> -	/* And the group descriptor block */
> -	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
> -	ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
> -	if (!err)
> -		err = ret;
> -
>  error_return:
> -	brelse(bitmap_bh);
>  	ext4_std_error(sb, err);
>  	return err;
>  }
> -- 
> 2.30.0