linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: support zero sized file truncate for device aliasing files

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Message-ID: <ea3988c6-7708-4da9-8009-85708a27275b@kernel.org>
Date: Tue, 18 Mar 2025 11:45:30 +0800
From: Chao Yu <chao@...nel.org>
To: Daeho Jeong <daeho43@...il.com>, linux-kernel@...r.kernel.org,
 linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc: chao@...nel.org, Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs: support zero sized file truncate for
 device aliasing files

On 3/18/25 03:08, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@...gle.com>
> 
> support a file truncation to zero size for device aliasing files.
> 
> Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> ---
>  fs/f2fs/file.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index f92a9fba9991..7ae5a5af5ed9 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1036,7 +1036,7 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>  
>  	if ((attr->ia_valid & ATTR_SIZE)) {
>  		if (!f2fs_is_compress_backend_ready(inode) ||
> -				IS_DEVICE_ALIASING(inode))
> +				(IS_DEVICE_ALIASING(inode) && attr->ia_size))
>  			return -EOPNOTSUPP;
>  		if (is_inode_flag_set(inode, FI_COMPRESS_RELEASED) &&
>  			!IS_ALIGNED(attr->ia_size,
> @@ -1117,6 +1117,9 @@ int f2fs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>  		if (err)
>  			return err;

Daeho,

If truncate(, 0) failed due to some reasons, maybe, the file was partially
truncated, should we tag it as inconsistent status to avoid its later access?
thoughts?

Thanks,

>  
> +		if (IS_DEVICE_ALIASING(inode))
> +			f2fs_destroy_extent_tree(inode);
> +
>  		spin_lock(&fi->i_size_lock);
>  		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
>  		fi->last_disk_size = i_size_read(inode);