linux-kernel - Re: [PATCH 1/3] ext4: treat end of range as exclusive in ext4_zero

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Message-ID: <20231019150108.mwzinguhn6zxrzbu@quack3>
Date:   Thu, 19 Oct 2023 17:01:08 +0200
From:   Jan Kara <jack@...e.cz>
To:     Ojaswin Mujoo <ojaswin@...ux.ibm.com>
Cc:     linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>,
        Ritesh Harjani <ritesh.list@...il.com>,
        linux-kernel@...r.kernel.org, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH 1/3] ext4: treat end of range as exclusive in
 ext4_zero_range()

On Fri 29-09-23 19:40:43, Ojaswin Mujoo wrote:
> The call to filemap_write_and_wait_range() assumes the range passed to be
> inclusive, so fix the call to make sure we follow that.
> 
> Signed-off-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>

Yes, makes sense. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/extents.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index e4115d338f10..c79b4c25afc4 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -4522,7 +4522,8 @@ static long ext4_zero_range(struct file *file, loff_t offset,
>  	 * Round up offset. This is not fallocate, we need to zero out
>  	 * blocks, so convert interior block aligned part of the range to
>  	 * unwritten and possibly manually zero out unaligned parts of the
> -	 * range.
> +	 * range. Here, start and partial_begin are inclusive, end and
> +	 * partial_end are exclusive.
>  	 */
>  	start = round_up(offset, 1 << blkbits);
>  	end = round_down((offset + len), 1 << blkbits);
> @@ -4608,7 +4609,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
>  		 * disk in case of crash before zeroing trans is committed.
>  		 */
>  		if (ext4_should_journal_data(inode)) {
> -			ret = filemap_write_and_wait_range(mapping, start, end);
> +			ret = filemap_write_and_wait_range(mapping, start, end - 1);
>  			if (ret) {
>  				filemap_invalidate_unlock(mapping);
>  				goto out_mutex;
> -- 
> 2.39.3
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR