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

[Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>]

From: Christian Brauner <christian.brauner@ubuntu.com>

Enable __ceph_setattr() to handle idmapped mounts. This is just a matter
of passing down the mount's idmapping.

Cc: Xiubo Li <xiubli@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: ceph-devel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
[ adapted to b27c82e12965 ("attr: port attribute changes to new types") ]
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
---
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;
 }
-- 
2.34.1