Re: [PATCH v4 3/8] xfs: only call posix_acl_create under CONFIG_XFS_POSIX_ACL

Christian Brauner
2022-04-19T13:53:16Z

On Tue, Apr 19, 2022 at 07:47:09PM +0800, Yang Xu wrote:
> Since xfs_generic_create only calls xfs_set_acl when enable this kconfig, we
> don't need to call posix_acl_create for the !CONFIG_XFS_POSIX_ACL case.
>
> The previous patch has added missing umask strip for tmpfile, so all creation
> paths handle umask in the vfs directly if the filesystem doesn't support or
> enable POSIX ACLs.
>
> So just put this function under CONFIG_XFS_POSIX_ACL and umask strip still works
> well.
>
> Also use unified rule for CONFIG_XFS_POSIX_ACL in this file, so use IS_ENABLED in
> xfs_generic_create.
>
> Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
> ---
> fs/xfs/xfs_iops.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index b34e8e4344a8..6b8df9ab215a 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -150,6 +150,7 @@ xfs_create_need_xattr(
> return true;
> if (default_acl)
> return true;
> +
> #if IS_ENABLED(CONFIG_SECURITY)
> if (dir->i_sb->s_security)
> return true;
> @@ -169,7 +170,7 @@ xfs_generic_create(
> {
> struct inode *inode;
> struct xfs_inode *ip = NULL;
> - struct posix_acl *default_acl, *acl;
> + struct posix_acl *default_acl = NULL, *acl = NULL;
> struct xfs_name name;
> int error;
>
> @@ -184,9 +185,11 @@ xfs_generic_create(
> rdev = 0;
> }
>
> +#if IS_ENABLED(CONFIG_XFS_POSIX_ACL)
> error = posix_acl_create(dir, &mode, &default_acl, &acl);
> if (error)
> return error;
> +#endif

Does this actually fix or improve anything?
If CONFIG_XFS_POSIX_ACL isn't selected then SB_POSIXACL won't be set in
inode->i_sb->s_flags and consequently posix_acl_create() is a nop. So
ifdefing this doesn't really do anything so I'd argue to not bother with
this change.

> /* Verify mode is valid also for tmpfile case */
> error = xfs_dentry_mode_to_name(&name, dentry, mode);
> @@ -209,7 +212,7 @@ xfs_generic_create(
> if (unlikely(error))
> goto out_cleanup_inode;
>
> -#ifdef CONFIG_XFS_POSIX_ACL
> +#if IS_ENABLED(CONFIG_XFS_POSIX_ACL)
> if (default_acl) {
> error = __xfs_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
> if (error)

Side-note, I think

#ifdef CONFIG_XFS_POSIX_ACL
extern struct posix_acl *xfs_get_acl(struct inode *inode, int type, bool rcu);
extern int xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
struct posix_acl *acl, int type);
extern int __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
#else
extern int xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
struct posix_acl *acl, int type)
{
return 0;
}

extern int __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
return 0;
}
#endif

and then removing the inline-ifdef might be an improvement.