[PATCH] erofs: mark inodes without acls in erofs_read_inode()

[Hongbo Li]

Hi, Xiang

On 2026/1/28 11:54, Gao Xiang wrote:
> Similar to commit 91ef18b567da ("ext4: mark inodes without acls in
> __ext4_iget()"), the ACL state won't be read when the file owner
> performs a lookup, and the RCU fast path for lookups won't work
> because the ACL state remains unknown.
> 
> If there are no extended attributes, or if the xattr filter
> indicates that no ACL xattr is present, call cache_no_acl() directly.
> 
> Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
> ---
>   fs/erofs/inode.c |  5 +++++
>   fs/erofs/xattr.c | 20 ++++++++++++++++++++
>   fs/erofs/xattr.h |  1 +
>   3 files changed, 26 insertions(+)
> 
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index bce98c845a18..2e02d4b466ce 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -137,6 +137,11 @@ static int erofs_read_inode(struct inode *inode)
>   		err = -EFSCORRUPTED;
>   		goto err_out;
>   	}
> +
> +	if (IS_ENABLED(CONFIG_EROFS_FS_POSIX_ACL) &&
> +	    erofs_inode_has_noacl(inode, ptr, ofs))
> +		cache_no_acl(inode);
> +
>   	switch (inode->i_mode & S_IFMT) {
>   	case S_IFDIR:
>   		vi->dot_omitted = (ifmt >> EROFS_I_DOT_OMITTED_BIT) & 1;
> diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
> index 512b998bdfff..14d22adc1476 100644
> --- a/fs/erofs/xattr.c
> +++ b/fs/erofs/xattr.c
> @@ -574,4 +574,24 @@ struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
>   	kfree(value);
>   	return acl;
>   }
> +
> +bool erofs_inode_has_noacl(struct inode *inode, void *kaddr, unsigned int ofs)
> +{

How about put the definition and declare of erofs_inode_has_noacl before 
the erofs_get_acl helper? Since it is no need to resolved the context 
conflicts for page sharing.

Otherwise it looks good to me:
Reviewed-by: Hongbo Li <lihongbo22 at huawei.com>

Thanks,
Hongbo

> +	static const unsigned int bitmask =
> +		BIT(21) |	/* system.posix_acl_default */
> +		BIT(30);	/* system.posix_acl_access */
> +	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
> +	const struct erofs_xattr_ibody_header *ih = kaddr + ofs;
> +
> +	if (EROFS_I(inode)->xattr_isize < sizeof(*ih))
> +		return true;
> +
> +	if (erofs_sb_has_xattr_filter(sbi) && !sbi->xattr_filter_reserved &&
> +	    !check_add_overflow(ofs, sizeof(*ih), &ofs) &&
> +	    ofs <= i_blocksize(inode)) {
> +		if ((ih->h_name_filter & bitmask) == bitmask)
> +			return true;
> +	}
> +	return false;
> +}
>   #endif
> diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
> index 36f2667afc2d..a3ceefa1554d 100644
> --- a/fs/erofs/xattr.h
> +++ b/fs/erofs/xattr.h
> @@ -30,4 +30,5 @@ struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu);
>   #define erofs_get_acl	(NULL)
>   #endif
>   
> +bool erofs_inode_has_noacl(struct inode *inode, void *kaddr, unsigned int ofs);
>   #endif