linux-ext4 - Re: [PATCH v3 1/7] ext4: Document an edge case for overwrites

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Message-ID: <20250514162347.GJ25655@frogsfrogsfrogs>
Date: Wed, 14 May 2025 09:23:47 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: "Ritesh Harjani (IBM)" <ritesh.list@...il.com>
Cc: linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>,
	Jan Kara <jack@...e.cz>, John Garry <john.g.garry@...cle.com>,
	Ojaswin Mujoo <ojaswin@...ux.ibm.com>,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v3 1/7] ext4: Document an edge case for overwrites

On Fri, May 09, 2025 at 02:20:31AM +0530, Ritesh Harjani (IBM) wrote:
> ext4_iomap_overwrite_begin() clears the flag for IOMAP_WRITE before
> calling ext4_iomap_begin(). Document this above ext4_map_blocks() call
> as it is easy to miss it when focusing on write paths alone.
> 
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>

Weird but ok,
Acked-by: "Darrick J. Wong" <djwong@...nel.org>

--D

> ---
>  fs/ext4/inode.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 94c7d2d828a6..b10e5cd5bb5c 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -3436,6 +3436,10 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
>  		}
>  		ret = ext4_iomap_alloc(inode, &map, flags);
>  	} else {
> +		/*
> +		 * This can be called for overwrites path from
> +		 * ext4_iomap_overwrite_begin().
> +		 */
>  		ret = ext4_map_blocks(NULL, inode, &map, 0);
>  	}
>  
> -- 
> 2.49.0
> 
>