linux-ext4 - Re: [PATCH 3/3] ext4: fix incorrect locking in move_extent_per

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Date:	Mon, 21 Jul 2014 21:51:02 +0200
From:	Jan Kara <jack@...e.cz>
To:	Dmitry Monakhov <dmonakhov@...nvz.org>
Cc:	linux-ext4@...r.kernel.org, tytso@....edu
Subject: Re: [PATCH 3/3] ext4: fix incorrect locking in move_extent_per_page

On Mon 21-07-14 19:04:49, Dmitry Monakhov wrote:
> If we have to copy data we must drop i_data_sem because of
> get_blocks() will be called inside mext_page_mkuptodate(), but later we must
> reacquire it again because we are about to change extent's tree
> 
> Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
  Looks good. You can add:
Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/move_extent.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
> index 2484c7e..671a74b 100644
> --- a/fs/ext4/move_extent.c
> +++ b/fs/ext4/move_extent.c
> @@ -1013,10 +1013,11 @@ data_copy:
>  		*err = -EBUSY;
>  		goto unlock_pages;
>  	}
> -
> +	ext4_double_down_write_data_sem(orig_inode, donor_inode);
>  	replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
>  					       orig_blk_offset,
>  					       block_len_in_page, err);
> +	ext4_double_up_write_data_sem(orig_inode, donor_inode);
>  	if (*err) {
>  		if (replaced_count) {
>  			block_len_in_page = replaced_count;
> -- 
> 1.7.1
> 
> --
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-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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