linux-ext4 - Re: [PATCH v2] ext2: add missing brelse in ext2_new

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Date:   Tue, 22 Oct 2019 11:25:55 +0200
From:   Jan Kara <jack@...e.cz>
To:     Chengguang Xu <cgxu519@...ernel.net>
Cc:     jack@...e.com, linux-ext4@...r.kernel.org
Subject: Re: [PATCH v2] ext2: add missing brelse in ext2_new_blocks()

On Tue 22-10-19 17:17:38, Chengguang Xu wrote:
> There is a missing brelse of bitmap_bh in the
> case of retry.
> 
> Signed-off-by: Chengguang Xu <cgxu519@...ernel.net>

Thanks. Patch applied with small update to the comment - this can also hit
in case our reservation window was alredy full.

								Honza

> ---
> v1->v2:
> - Add comment to explain why the fix is needed.
> 
>  fs/ext2/balloc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
> index 924c1c765306..18e75adcd2f6 100644
> --- a/fs/ext2/balloc.c
> +++ b/fs/ext2/balloc.c
> @@ -1313,6 +1313,13 @@ ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
>  	if (free_blocks > 0) {
>  		grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
>  				EXT2_BLOCKS_PER_GROUP(sb));
> +		/*
> +		 * In a special case that allocated blocks are in system zone,
> +		 * we will retry block allocation due to failing to pass sanity
> +		 * check. In this case, the bitmap_bh is non-null pointer and we
> +		 * have to release it before calling read_block_bitmap().
> +		 */
> +		brelse(bitmap_bh);
>  		bitmap_bh = read_block_bitmap(sb, group_no);
>  		if (!bitmap_bh)
>  			goto io_error;
> -- 
> 2.20.1
> 
> 
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR