Re: [PATCH v4 11/14] ceph: allow idmapped setattr inode op

[Xiubo Li <xiubli@xxxxxxxxxx>]

On 6/8/23 02:09, Alexander Mikhalitsyn wrote:
> From: Christian Brauner <christian.brauner@xxxxxxxxxx>
>
> Enable __ceph_setattr() to handle idmapped mounts. This is just a matter
> of passing down the mount's idmapping.
>
> Cc: Xiubo Li <xiubli@xxxxxxxxxx>
> Cc: Jeff Layton <jlayton@xxxxxxxxxx>
> Cc: Ilya Dryomov <idryomov@xxxxxxxxx>
> Cc: ceph-devel@xxxxxxxxxxxxxxx
> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
> [ adapted to b27c82e12965 ("attr: port attribute changes to new types") ]
> Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>
> ---
> v4:
> 	- introduced fsuid/fsgid local variables
> v3:
> 	- reworked as Christian suggested here:
> 	https://lore.kernel.org/lkml/20230602-vorzeichen-praktikum-f17931692301@brauner/
> ---
>   fs/ceph/inode.c | 20 ++++++++++++--------
>   1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index bcd9b506ec3b..ca438d1353b2 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -2052,31 +2052,35 @@ int __ceph_setattr(struct mnt_idmap *idmap, struct inode *inode,
>   	dout("setattr %p issued %s\n", inode, ceph_cap_string(issued));
>   
>   	if (ia_valid & ATTR_UID) {
> +		kuid_t fsuid = from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid);
> +
>   		dout("setattr %p uid %d -> %d\n", inode,
>   		     from_kuid(&init_user_ns, inode->i_uid),
>   		     from_kuid(&init_user_ns, attr->ia_uid));
>   		if (issued & CEPH_CAP_AUTH_EXCL) {
> -			inode->i_uid = attr->ia_uid;
> +			inode->i_uid = fsuid;
>   			dirtied |= CEPH_CAP_AUTH_EXCL;
>   		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
> -			   !uid_eq(attr->ia_uid, inode->i_uid)) {
> +			   !uid_eq(fsuid, inode->i_uid)) {
>   			req->r_args.setattr.uid = cpu_to_le32(
> -				from_kuid(&init_user_ns, attr->ia_uid));
> +				from_kuid(&init_user_ns, fsuid));
>   			mask |= CEPH_SETATTR_UID;
>   			release |= CEPH_CAP_AUTH_SHARED;
>   		}
>   	}
>   	if (ia_valid & ATTR_GID) {
> +		kgid_t fsgid = from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid);
> +
>   		dout("setattr %p gid %d -> %d\n", inode,
>   		     from_kgid(&init_user_ns, inode->i_gid),
>   		     from_kgid(&init_user_ns, attr->ia_gid));
>   		if (issued & CEPH_CAP_AUTH_EXCL) {
> -			inode->i_gid = attr->ia_gid;
> +			inode->i_gid = fsgid;
>   			dirtied |= CEPH_CAP_AUTH_EXCL;
>   		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
> -			   !gid_eq(attr->ia_gid, inode->i_gid)) {
> +			   !gid_eq(fsgid, inode->i_gid)) {
>   			req->r_args.setattr.gid = cpu_to_le32(
> -				from_kgid(&init_user_ns, attr->ia_gid));
> +				from_kgid(&init_user_ns, fsgid));
>   			mask |= CEPH_SETATTR_GID;
>   			release |= CEPH_CAP_AUTH_SHARED;
>   		}
> @@ -2241,7 +2245,7 @@ int ceph_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>   	if (ceph_inode_is_shutdown(inode))
>   		return -ESTALE;
>   
> -	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
> +	err = setattr_prepare(idmap, dentry, attr);
>   	if (err != 0)
>   		return err;
>   
> @@ -2256,7 +2260,7 @@ int ceph_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>   	err = __ceph_setattr(idmap, inode, attr);
>   
>   	if (err >= 0 && (attr->ia_valid & ATTR_MODE))
> -		err = posix_acl_chmod(&nop_mnt_idmap, dentry, attr->ia_mode);
> +		err = posix_acl_chmod(idmap, dentry, attr->ia_mode);
>   
>   	return err;
>   }

You should also do 'req->r_mnt_idmap = idmap;' for sync setattr request.

the setattr will just cache the change locally in client side if the 'x' 
caps are issued and returns directly or will set a sync setattr reqeust.

Thanks

- Xiubo