linux-ext4 - Re: [PATCH v3 2/7] ext4: Check if inode uses extents in ext4_inode_can_atomic

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Message-ID: <20250514162433.GK25655@frogsfrogsfrogs>
Date: Wed, 14 May 2025 09:24:33 -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 2/7] ext4: Check if inode uses extents in
 ext4_inode_can_atomic_write()

On Fri, May 09, 2025 at 02:20:32AM +0530, Ritesh Harjani (IBM) wrote:
> EXT4 only supports doing atomic write on inodes which uses extents, so
> add a check in ext4_inode_can_atomic_write() which gets called during
> open.
> 
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@...il.com>

Makes sense seeing as advertising the awu geometry is gated on the
filesystem having extents turned on...

Acked-by: "Darrick J. Wong" <djwong@...nel.org>

--D

> ---
>  fs/ext4/ext4.h | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 5a20e9cd7184..c0240f6f6491 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -3847,7 +3847,9 @@ static inline int ext4_buffer_uptodate(struct buffer_head *bh)
>  static inline bool ext4_inode_can_atomic_write(struct inode *inode)
>  {
>  
> -	return S_ISREG(inode->i_mode) && EXT4_SB(inode->i_sb)->s_awu_min > 0;
> +	return S_ISREG(inode->i_mode) &&
> +		ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
> +		EXT4_SB(inode->i_sb)->s_awu_min > 0;
>  }
>  
>  extern int ext4_block_write_begin(handle_t *handle, struct folio *folio,
> -- 
> 2.49.0
> 
>