[PATCH v3 11/14] ceph: allow idmapped setattr inode op

[Alexander Mikhalitsyn <aleksandr.mikhalitsyn@xxxxxxxxxxxxx>]

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>
---
v3:
	- reworked as Christian suggested here:
	https://lore.kernel.org/lkml/20230602-vorzeichen-praktikum-f17931692301@brauner/
---
 fs/ceph/inode.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index bcd9b506ec3b..09c78a67738b 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2051,17 +2051,27 @@ int __ceph_setattr(struct mnt_idmap *idmap, struct inode *inode,
 
 	dout("setattr %p issued %s\n", inode, ceph_cap_string(issued));
 
+	/*
+	 * The attr->ia_{g,u}id members contain the target {g,u}id we're
+	 * sending over the wire. The mount idmapping only matters when we
+	 * create new filesystem objects based on the caller's mapped
+	 * fs{g,u}id.
+	 */
+	req->r_mnt_idmap = &nop_mnt_idmap;
 	if (ia_valid & ATTR_UID) {
 		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 = from_vfsuid(idmap, i_user_ns(inode),
+						   attr->ia_vfsuid);
 			dirtied |= CEPH_CAP_AUTH_EXCL;
 		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
-			   !uid_eq(attr->ia_uid, inode->i_uid)) {
+			   !uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
+				   inode->i_uid)) {
+			kuid_t fsuid = from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid);
 			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;
 		}
@@ -2071,12 +2081,15 @@ int __ceph_setattr(struct mnt_idmap *idmap, struct inode *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 = from_vfsgid(idmap, i_user_ns(inode),
+						   attr->ia_vfsgid);
 			dirtied |= CEPH_CAP_AUTH_EXCL;
 		} else if ((issued & CEPH_CAP_AUTH_SHARED) == 0 ||
-			   !gid_eq(attr->ia_gid, inode->i_gid)) {
+			   !gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
+				   inode->i_gid)) {
+			kgid_t fsgid = from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid);
 			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 +2254,7 @@ 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 +2269,7 @@ 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