linux-ext4 - Re: [PATCH v3 03/26] ext4: correct the hole length returned by ext4_map

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Date: Sat, 3 Feb 2024 12:56:39 -0500
From: "Theodore Ts'o" <tytso@....edu>
To: Zhang Yi <yi.zhang@...weicloud.com>
Cc: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        adilger.kernel@...ger.ca, jack@...e.cz, ritesh.list@...il.com,
        hch@...radead.org, djwong@...nel.org, willy@...radead.org,
        zokeefe@...gle.com, yi.zhang@...wei.com, chengzhihao1@...wei.com,
        yukuai3@...wei.com, wangkefeng.wang@...wei.com
Subject: Re: [PATCH v3 03/26] ext4: correct the hole length returned by
 ext4_map_blocks()

On Sat, Jan 27, 2024 at 09:58:02AM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@...wei.com>
> 
> In ext4_map_blocks(), if we can't find a range of mapping in the
> extents cache, we are calling ext4_ext_map_blocks() to search the real
> path and ext4_ext_determine_hole() to determine the hole range. But if
> the querying range was partially or completely overlaped by a delalloc
> extent, we can't find it in the real extent path, so the returned hole
> length could be incorrect.
> 
> Fortunately, ext4_ext_put_gap_in_cache() have already handle delalloc
> extent, but it searches start from the expanded hole_start, doesn't
> start from the querying range, so the delalloc extent found could not be
> the one that overlaped the querying range, plus, it also didn't adjust
> the hole length. Let's just remove ext4_ext_put_gap_in_cache(), handle
> delalloc and insert adjusted hole extent in ext4_ext_determine_hole().
> 
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
> Suggested-by: Jan Kara <jack@...e.cz>
> Reviewed-by: Jan Kara <jack@...e.cz>

Thanks, applied.

					- Ted