[PATCH 11/12] ceph/file: allow idmapped atomic_open inode op

[Christian Brauner <brauner@kernel.org>]

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

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

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>
---
 fs/ceph/file.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index c138e8126286..7fecb41796c7 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -608,7 +608,10 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 	in.truncate_seq = cpu_to_le32(1);
 	in.truncate_size = cpu_to_le64(-1ULL);
 	in.xattr_version = cpu_to_le64(1);
-	in.uid = cpu_to_le32(from_kuid(&init_user_ns, current_fsuid()));
+	in.uid = cpu_to_le32(from_kuid(&init_user_ns,
+				       mapped_kuid_user(req->mnt_userns,
+							&init_user_ns,
+							current_fsuid())));
 	if (dir->i_mode & S_ISGID) {
 		in.gid = cpu_to_le32(from_kgid(&init_user_ns, dir->i_gid));
 
@@ -616,11 +619,14 @@ static int ceph_finish_async_create(struct inode *dir, struct dentry *dentry,
 		if (S_ISDIR(mode))
 			mode |= S_ISGID;
 		else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
-			 !in_group_p(dir->i_gid) &&
-			 !capable_wrt_inode_uidgid(&init_user_ns, dir, CAP_FSETID))
+			 !in_group_p(i_gid_into_mnt(req->mnt_userns, dir)) &&
+			 !capable_wrt_inode_uidgid(req->mnt_userns, dir, CAP_FSETID))
 			mode &= ~S_ISGID;
 	} else {
-		in.gid = cpu_to_le32(from_kgid(&init_user_ns, current_fsgid()));
+		in.gid = cpu_to_le32(from_kgid(&init_user_ns,
+				     mapped_kgid_user(req->mnt_userns,
+						      &init_user_ns,
+						      current_fsgid())));
 	}
 	in.mode = cpu_to_le32((u32)mode);
 
@@ -677,6 +683,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 		     struct file *file, unsigned flags, umode_t mode)
 {
 	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
+	struct user_namespace *mnt_userns = file_mnt_user_ns(file);
 	struct ceph_mds_client *mdsc = fsc->mdsc;
 	struct ceph_mds_request *req;
 	struct dentry *dn;
@@ -719,6 +726,7 @@ int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
 		mask |= CEPH_CAP_XATTR_SHARED;
 	req->r_args.open.mask = cpu_to_le32(mask);
 	req->r_parent = dir;
+	req->mnt_userns = mnt_userns;
 	ihold(dir);
 
 	if (flags & O_CREAT) {
-- 
2.32.0