fs: make helpers idmap mount aware

Extend some inode methods with an additional user namespace argument. A
filesystem that is aware of idmapped mounts will receive the user
namespace the mount has been marked with. This can be used for
additional permission checking and also to enable filesystems to
translate between uids and gids if they need to. We have implemented all
relevant helpers in earlier patches.

As requested we simply extend the exisiting inode method instead of
introducing new ones. This is a little more code churn but it's mostly
mechanical and doesnt't leave us with additional inode methods.

Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

4 files changed, 28 insertions, 20 deletions

diff --git a/fs/ceph/acl.c b/fs/ceph/acl.c
index 52a01ddbc4ac..529af59d9fd3 100644
--- a/fs/ceph/acl.c
+++ b/fs/ceph/acl.c
@@ -82,7 +82,8 @@ retry:
 	return acl;
 }
 
-int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type)
+int ceph_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
+		 struct posix_acl *acl, int type)
 {
 	int ret = 0, size = 0;
 	const char *name = NULL;
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index 858ee7362ff5..83d9358854fb 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -823,8 +823,8 @@ int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry)
 	return PTR_ERR(result);
 }
 
-static int ceph_mknod(struct inode *dir, struct dentry *dentry,
-		      umode_t mode, dev_t rdev)
+static int ceph_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_mds_request *req;
@@ -878,14 +878,14 @@ out:
 	return err;
 }
 
-static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
-		       bool excl)
+static int ceph_create(struct user_namespace *mnt_userns, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, bool excl)
 {
-	return ceph_mknod(dir, dentry, mode, 0);
+	return ceph_mknod(mnt_userns, dir, dentry, mode, 0);
 }
 
-static int ceph_symlink(struct inode *dir, struct dentry *dentry,
-			    const char *dest)
+static int ceph_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+			struct dentry *dentry, const char *dest)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_mds_request *req;
@@ -937,7 +937,8 @@ out:
 	return err;
 }
 
-static int ceph_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+static int ceph_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+		      struct dentry *dentry, umode_t mode)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(dir->i_sb);
 	struct ceph_mds_request *req;
@@ -1183,9 +1184,9 @@ out:
 	return err;
 }
 
-static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
-		       struct inode *new_dir, struct dentry *new_dentry,
-		       unsigned int flags)
+static int ceph_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
+		       struct dentry *old_dentry, struct inode *new_dir,
+		       struct dentry *new_dentry, unsigned int flags)
 {
 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(old_dir->i_sb);
 	struct ceph_mds_request *req;
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 179a2bb88538..d6ece56d40e8 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -2238,7 +2238,8 @@ int __ceph_setattr(struct inode *inode, struct iattr *attr)
 /*
  * setattr
  */
-int ceph_setattr(struct dentry *dentry, struct iattr *attr)
+int ceph_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		 struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
 	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
@@ -2321,7 +2322,8 @@ int __ceph_do_getattr(struct inode *inode, struct page *locked_page,
  * Check inode permissions.  We verify we have a valid value for
  * the AUTH cap, then call the generic handler.
  */
-int ceph_permission(struct inode *inode, int mask)
+int ceph_permission(struct user_namespace *mnt_userns, struct inode *inode,
+		    int mask)
 {
 	int err;
 
@@ -2368,8 +2370,8 @@ static int statx_to_caps(u32 want, umode_t mode)
  * Get all the attributes. If we have sufficient caps for the requested attrs,
  * then we can avoid talking to the MDS at all.
  */
-int ceph_getattr(const struct path *path, struct kstat *stat,
-		 u32 request_mask, unsigned int flags)
+int ceph_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		 struct kstat *stat, u32 request_mask, unsigned int flags)
 {
 	struct inode *inode = d_inode(path->dentry);
 	struct ceph_inode_info *ci = ceph_inode(inode);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b62d8fee3b86..1ef0a2a15817 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -973,10 +973,13 @@ static inline int ceph_do_getattr(struct inode *inode, int mask, bool force)
 {
 	return __ceph_do_getattr(inode, NULL, mask, force);
 }
-extern int ceph_permission(struct inode *inode, int mask);
+extern int ceph_permission(struct user_namespace *mnt_userns,
+			   struct inode *inode, int mask);
 extern int __ceph_setattr(struct inode *inode, struct iattr *attr);
-extern int ceph_setattr(struct dentry *dentry, struct iattr *attr);
-extern int ceph_getattr(const struct path *path, struct kstat *stat,
+extern int ceph_setattr(struct user_namespace *mnt_userns,
+			struct dentry *dentry, struct iattr *attr);
+extern int ceph_getattr(struct user_namespace *mnt_userns,
+			const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int flags);
 
 /* xattr.c */
@@ -1037,7 +1040,8 @@ void ceph_release_acl_sec_ctx(struct ceph_acl_sec_ctx *as_ctx);
 #ifdef CONFIG_CEPH_FS_POSIX_ACL
 
 struct posix_acl *ceph_get_acl(struct inode *, int);
-int ceph_set_acl(struct inode *inode, struct posix_acl *acl, int type);
+int ceph_set_acl(struct user_namespace *mnt_userns,
+		 struct inode *inode, struct posix_acl *acl, int type);
 int ceph_pre_init_acls(struct inode *dir, umode_t *mode,
 		       struct ceph_acl_sec_ctx *as_ctx);
 void ceph_init_inode_acls(struct inode *inode,