linux-kernel - Re: [PATCH] jffs2: use fs_umode_to

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Message-ID: <134dec36-3bcf-89a4-2817-a880afa4280f@huawei.com>
Date: Sat, 7 Feb 2026 10:36:29 +0800
From: Zhihao Cheng <chengzhihao1@...wei.com>
To: Adarsh Das <adarshdas950@...il.com>, <dwmw2@...radead.org>,
	<richard@....at>
CC: <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] jffs2: use fs_umode_to_dtype() for dirent type

在 2026/2/6 19:51, Adarsh Das 写道:
> Use fs_umode_to_dtype() instead of direct bit shifting when
> setting directory entry type.
> 
> Signed-off-by: Adarsh Das <adarshdas950@...il.com>
> ---
>   fs/jffs2/dir.c | 11 +++--------
>   1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
> index dd91f725ded6..185cf76a061e 100644
> --- a/fs/jffs2/dir.c
> +++ b/fs/jffs2/dir.c
> @@ -261,8 +261,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
>   	if (d_is_dir(old_dentry))
>   		return -EPERM;
>   
> -	/* XXX: This is ugly */
> -	type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12;
> +	type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode);
>   	if (!type) type = DT_REG;

Hi Adarsh,
The convertion result is wrong for jffs2_do_link.
The i_mode of old_dentry is 'S_IFIFO', the jffs2 gets type DT_FIFO(1) 
and pass it to 'rd->type' by jffs2_do_link. However, after the patch 
applied, jffs2 gets type FT_FIFO(5), which will confuse other 'rd->type' 
accessing processes(eg. jffs2_scan_dirent_node[rd->type], 
jffs2_build_filesystem[fd->type]).

>   
>   	now = JFFS2_NOW();
> @@ -730,10 +729,7 @@ static int jffs2_mknod (struct mnt_idmap *idmap, struct inode *dir_i,
>   	rd->ino = cpu_to_je32(inode->i_ino);
>   	rd->mctime = cpu_to_je32(JFFS2_NOW());
>   	rd->nsize = namelen;
> -
> -	/* XXX: This is ugly. */
> -	rd->type = (mode & S_IFMT) >> 12;
> -
> +	rd->type = fs_umode_to_dtype(mode);
>   	rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
>   	rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));
>   
> @@ -811,8 +807,7 @@ static int jffs2_rename (struct mnt_idmap *idmap,
>   
>   	/* Make a hard link */
>   
> -	/* XXX: This is ugly */
> -	type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12;
> +	type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode);
>   	if (!type) type = DT_REG;
>   
>   	now = JFFS2_NOW();
>