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Message-ID: <ed15e402-d888-453a-b0f4-3fcff069e5fd@kernel.org>
Date: Tue, 12 Mar 2024 09:50:39 +0800
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Subject: Re: [f2fs-dev] [PATCH 2/2] f2fs: prevent writing without fallocate()
 for pinned files
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To: Daeho Jeong <daeho43@gmail.com>, linux-kernel@vger.kernel.org,
 linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
Cc: Daeho Jeong <daehojeong@google.com>
References: <20240311235921.1832684-1-daeho43@gmail.com>
 <20240311235921.1832684-2-daeho43@gmail.com>
From: Chao Yu <chao@kernel.org>
In-Reply-To: <20240311235921.1832684-2-daeho43@gmail.com>
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On 2024/3/12 7:59, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> In a case writing without fallocate(), we can't guarantee it's allocated
> in the conventional area for zoned stroage.
> 
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> ---
>   fs/f2fs/data.c | 7 +++++++
>   fs/f2fs/file.c | 4 ++++
>   2 files changed, 11 insertions(+)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index c21b92f18463..5e4c11a719a0 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -3378,6 +3378,8 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
>   		f2fs_map_lock(sbi, flag);
>   		locked = true;
>   	} else if ((pos & PAGE_MASK) >= i_size_read(inode)) {
> +		if (f2fs_is_pinned_file(inode))
> +			return -EIO;
>   		f2fs_map_lock(sbi, flag);
>   		locked = true;
>   	}
> @@ -3407,6 +3409,11 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
>   
>   	if (!f2fs_lookup_read_extent_cache_block(inode, index,
>   						 &dn.data_blkaddr)) {
> +		if (f2fs_is_pinned_file(inode)) {
> +			err = -EIO;
> +			goto out;
> +		}

Daeho,

Do we need to check in DIO path as well?

Thanks,

> +
>   		if (locked) {
>   			err = f2fs_reserve_block(&dn, index);
>   			goto out;
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 82277e95c88f..f98730932fc4 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4611,6 +4611,10 @@ static int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *iter,
>   			return ret;
>   	}
>   
> +	/* For pinned files, it should be fallocate()-ed in advance. */
> +	if (f2fs_is_pinned_file(inode))
> +		return 0;
> +
>   	/* Do not preallocate blocks that will be written partially in 4KB. */
>   	map.m_lblk = F2FS_BLK_ALIGN(pos);
>   	map.m_len = F2FS_BYTES_TO_BLK(pos + count);