Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull vfs idmapping updates from Christian Brauner:

 - Last cycle we introduced the dedicated struct mnt_idmap type for
   mount idmapping and the required infrastucture in 256c8aed2b42 ("fs:
   introduce dedicated idmap type for mounts"). As promised in last
   cycle's pull request message this converts everything to rely on
   struct mnt_idmap.

   Currently we still pass around the plain namespace that was attached
   to a mount. This is in general pretty convenient but it makes it easy
   to conflate namespaces that are relevant on the filesystem with
   namespaces that are relevant on the mount level. Especially for
   non-vfs developers without detailed knowledge in this area this was a
   potential source for bugs.

   This finishes the conversion. Instead of passing the plain namespace
   around this updates all places that currently take a pointer to a
   mnt_userns with a pointer to struct mnt_idmap.

   Now that the conversion is done all helpers down to the really
   low-level helpers only accept a struct mnt_idmap argument instead of
   two namespace arguments.

   Conflating mount and other idmappings will now cause the compiler to
   complain loudly thus eliminating the possibility of any bugs. This
   makes it impossible for filesystem developers to mix up mount and
   filesystem idmappings as they are two distinct types and require
   distinct helpers that cannot be used interchangeably.

   Everything associated with struct mnt_idmap is moved into a single
   separate file. With that change no code can poke around in struct
   mnt_idmap. It can only be interacted with through dedicated helpers.
   That means all filesystems are and all of the vfs is completely
   oblivious to the actual implementation of idmappings.

   We are now also able to extend struct mnt_idmap as we see fit. For
   example, we can decouple it completely from namespaces for users that
   don't require or don't want to use them at all. We can also extend
   the concept of idmappings so we can cover filesystem specific
   requirements.

   In combination with the vfs{g,u}id_t work we finished in v6.2 this
   makes this feature substantially more robust and thus difficult to
   implement wrong by a given filesystem and also protects the vfs.

 - Enable idmapped mounts for tmpfs and fulfill a longstanding request.

   A long-standing request from users had been to make it possible to
   create idmapped mounts for tmpfs. For example, to share the host's
   tmpfs mount between multiple sandboxes. This is a prerequisite for
   some advanced Kubernetes cases. Systemd also has a range of use-cases
   to increase service isolation. And there are more users of this.

   However, with all of the other work going on this was way down on the
   priority list but luckily someone other than ourselves picked this
   up.

   As usual the patch is tiny as all the infrastructure work had been
   done multiple kernel releases ago. In addition to all the tests that
   we already have I requested that Rodrigo add a dedicated tmpfs
   testsuite for idmapped mounts to xfstests. It is to be included into
   xfstests during the v6.3 development cycle. This should add a slew of
   additional tests.

* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
  shmem: support idmapped mounts for tmpfs
  fs: move mnt_idmap
  fs: port vfs{g,u}id helpers to mnt_idmap
  fs: port fs{g,u}id helpers to mnt_idmap
  fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
  fs: port i_{g,u}id_{needs_}update() to mnt_idmap
  quota: port to mnt_idmap
  fs: port privilege checking helpers to mnt_idmap
  fs: port inode_owner_or_capable() to mnt_idmap
  fs: port inode_init_owner() to mnt_idmap
  fs: port acl to mnt_idmap
  fs: port xattr to mnt_idmap
  fs: port ->permission() to pass mnt_idmap
  fs: port ->fileattr_set() to pass mnt_idmap
  fs: port ->set_acl() to pass mnt_idmap
  fs: port ->get_acl() to pass mnt_idmap
  fs: port ->tmpfile() to pass mnt_idmap
  fs: port ->rename() to pass mnt_idmap
  fs: port ->mknod() to pass mnt_idmap
  fs: port ->mkdir() to pass mnt_idmap
  ...

6 files changed, 37 insertions, 37 deletions

diff --git a/fs/gfs2/acl.c b/fs/gfs2/acl.c
index 3dcde4912413..a392aa0f041d 100644
--- a/fs/gfs2/acl.c
+++ b/fs/gfs2/acl.c
@@ -109,7 +109,7 @@ out:
 	return error;
 }
 
-int gfs2_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
+int gfs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		 struct posix_acl *acl, int type)
 {
 	struct inode *inode = d_inode(dentry);
@@ -135,7 +135,7 @@ int gfs2_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
 
 	mode = inode->i_mode;
 	if (type == ACL_TYPE_ACCESS && acl) {
-		ret = posix_acl_update_mode(&init_user_ns, inode, &mode, &acl);
+		ret = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode, &acl);
 		if (ret)
 			goto unlock;
 	}
diff --git a/fs/gfs2/acl.h b/fs/gfs2/acl.h
index b8de8c148f5c..d4deb2b19959 100644
--- a/fs/gfs2/acl.h
+++ b/fs/gfs2/acl.h
@@ -13,7 +13,7 @@
 
 extern struct posix_acl *gfs2_get_acl(struct inode *inode, int type, bool rcu);
 extern int __gfs2_set_acl(struct inode *inode, struct posix_acl *acl, int type);
-extern int gfs2_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
+extern int gfs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 			struct posix_acl *acl, int type);
 
 #endif /* __ACL_DOT_H__ */
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index e8e20a716004..300844f50dcd 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -236,7 +236,7 @@ static int do_gfs2_set_flags(struct inode *inode, u32 reqflags, u32 mask)
 		goto out;
 
 	if (!IS_IMMUTABLE(inode)) {
-		error = gfs2_permission(&init_user_ns, inode, MAY_WRITE);
+		error = gfs2_permission(&nop_mnt_idmap, inode, MAY_WRITE);
 		if (error)
 			goto out;
 	}
@@ -274,7 +274,7 @@ out:
 	return error;
 }
 
-int gfs2_fileattr_set(struct user_namespace *mnt_userns,
+int gfs2_fileattr_set(struct mnt_idmap *idmap,
 		      struct dentry *dentry, struct fileattr *fa)
 {
 	struct inode *inode = d_inode(dentry);
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 614db3055c02..713efa3bb732 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -320,7 +320,7 @@ struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 	}
 
 	if (!is_root) {
-		error = gfs2_permission(&init_user_ns, dir, MAY_EXEC);
+		error = gfs2_permission(&nop_mnt_idmap, dir, MAY_EXEC);
 		if (error)
 			goto out;
 	}
@@ -350,7 +350,7 @@ static int create_ok(struct gfs2_inode *dip, const struct qstr *name,
 {
 	int error;
 
-	error = gfs2_permission(&init_user_ns, &dip->i_inode,
+	error = gfs2_permission(&nop_mnt_idmap, &dip->i_inode,
 				MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;
@@ -843,7 +843,7 @@ fail:
 
 /**
  * gfs2_create - Create a file
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The directory in which to create the file
  * @dentry: The dentry of the new file
  * @mode: The mode of the new file
@@ -852,7 +852,7 @@ fail:
  * Returns: errno
  */
 
-static int gfs2_create(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_create(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, bool excl)
 {
 	return gfs2_create_inode(dir, dentry, NULL, S_IFREG | mode, 0, NULL, 0, excl);
@@ -960,7 +960,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
 	if (inode->i_nlink == 0)
 		goto out_gunlock;
 
-	error = gfs2_permission(&init_user_ns, dir, MAY_WRITE | MAY_EXEC);
+	error = gfs2_permission(&nop_mnt_idmap, dir, MAY_WRITE | MAY_EXEC);
 	if (error)
 		goto out_gunlock;
 
@@ -1078,7 +1078,7 @@ static int gfs2_unlink_ok(struct gfs2_inode *dip, const struct qstr *name,
 	if (IS_APPEND(&dip->i_inode))
 		return -EPERM;
 
-	error = gfs2_permission(&init_user_ns, &dip->i_inode,
+	error = gfs2_permission(&nop_mnt_idmap, &dip->i_inode,
 				MAY_WRITE | MAY_EXEC);
 	if (error)
 		return error;
@@ -1207,7 +1207,7 @@ out_inodes:
 
 /**
  * gfs2_symlink - Create a symlink
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The directory to create the symlink in
  * @dentry: The dentry to put the symlink in
  * @symname: The thing which the link points to
@@ -1215,7 +1215,7 @@ out_inodes:
  * Returns: errno
  */
 
-static int gfs2_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *dentry, const char *symname)
 {
 	unsigned int size;
@@ -1229,7 +1229,7 @@ static int gfs2_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 
 /**
  * gfs2_mkdir - Make a directory
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The parent directory of the new one
  * @dentry: The dentry of the new directory
  * @mode: The mode of the new directory
@@ -1237,7 +1237,7 @@ static int gfs2_symlink(struct user_namespace *mnt_userns, struct inode *dir,
  * Returns: errno
  */
 
-static int gfs2_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	unsigned dsize = gfs2_max_stuffed_size(GFS2_I(dir));
@@ -1246,7 +1246,7 @@ static int gfs2_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 
 /**
  * gfs2_mknod - Make a special file
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dir: The directory in which the special file will reside
  * @dentry: The dentry of the special file
  * @mode: The mode of the special file
@@ -1254,7 +1254,7 @@ static int gfs2_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
  *
  */
 
-static int gfs2_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+static int gfs2_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, dev_t dev)
 {
 	return gfs2_create_inode(dir, dentry, NULL, mode, dev, NULL, 0, 0);
@@ -1504,7 +1504,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 			}
 		}
 	} else {
-		error = gfs2_permission(&init_user_ns, ndir,
+		error = gfs2_permission(&nop_mnt_idmap, ndir,
 					MAY_WRITE | MAY_EXEC);
 		if (error)
 			goto out_gunlock;
@@ -1541,7 +1541,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	/* Check out the dir to be renamed */
 
 	if (dir_rename) {
-		error = gfs2_permission(&init_user_ns, d_inode(odentry),
+		error = gfs2_permission(&nop_mnt_idmap, d_inode(odentry),
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
@@ -1705,13 +1705,13 @@ static int gfs2_exchange(struct inode *odir, struct dentry *odentry,
 		goto out_gunlock;
 
 	if (S_ISDIR(old_mode)) {
-		error = gfs2_permission(&init_user_ns, odentry->d_inode,
+		error = gfs2_permission(&nop_mnt_idmap, odentry->d_inode,
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
 	}
 	if (S_ISDIR(new_mode)) {
-		error = gfs2_permission(&init_user_ns, ndentry->d_inode,
+		error = gfs2_permission(&nop_mnt_idmap, ndentry->d_inode,
 					MAY_WRITE);
 		if (error)
 			goto out_gunlock;
@@ -1766,7 +1766,7 @@ out:
 	return error;
 }
 
-static int gfs2_rename2(struct user_namespace *mnt_userns, struct inode *odir,
+static int gfs2_rename2(struct mnt_idmap *idmap, struct inode *odir,
 			struct dentry *odentry, struct inode *ndir,
 			struct dentry *ndentry, unsigned int flags)
 {
@@ -1841,7 +1841,7 @@ out:
 
 /**
  * gfs2_permission
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @inode: The inode
  * @mask: The mask to be tested
  *
@@ -1852,7 +1852,7 @@ out:
  * Returns: errno
  */
 
-int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
+int gfs2_permission(struct mnt_idmap *idmap, struct inode *inode,
 		    int mask)
 {
 	struct gfs2_inode *ip;
@@ -1872,7 +1872,7 @@ int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
 	if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
 		error = -EPERM;
 	else
-		error = generic_permission(&init_user_ns, inode, mask);
+		error = generic_permission(&nop_mnt_idmap, inode, mask);
 	if (gfs2_holder_initialized(&i_gh))
 		gfs2_glock_dq_uninit(&i_gh);
 
@@ -1881,7 +1881,7 @@ int gfs2_permission(struct user_namespace *mnt_userns, struct inode *inode,
 
 static int __gfs2_setattr_simple(struct inode *inode, struct iattr *attr)
 {
-	setattr_copy(&init_user_ns, inode, attr);
+	setattr_copy(&nop_mnt_idmap, inode, attr);
 	mark_inode_dirty(inode);
 	return 0;
 }
@@ -1966,7 +1966,7 @@ out:
 
 /**
  * gfs2_setattr - Change attributes on an inode
- * @mnt_userns: User namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @dentry: The dentry which is changing
  * @attr: The structure describing the change
  *
@@ -1976,7 +1976,7 @@ out:
  * Returns: errno
  */
 
-static int gfs2_setattr(struct user_namespace *mnt_userns,
+static int gfs2_setattr(struct mnt_idmap *idmap,
 			struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = d_inode(dentry);
@@ -1992,11 +1992,11 @@ static int gfs2_setattr(struct user_namespace *mnt_userns,
 	if (error)
 		goto out;
 
-	error = may_setattr(&init_user_ns, inode, attr->ia_valid);
+	error = may_setattr(&nop_mnt_idmap, inode, attr->ia_valid);
 	if (error)
 		goto error;
 
-	error = setattr_prepare(&init_user_ns, dentry, attr);
+	error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (error)
 		goto error;
 
@@ -2007,7 +2007,7 @@ static int gfs2_setattr(struct user_namespace *mnt_userns,
 	else {
 		error = gfs2_setattr_simple(inode, attr);
 		if (!error && attr->ia_valid & ATTR_MODE)
-			error = posix_acl_chmod(&init_user_ns, dentry,
+			error = posix_acl_chmod(&nop_mnt_idmap, dentry,
 						inode->i_mode);
 	}
 
@@ -2022,7 +2022,7 @@ out:
 
 /**
  * gfs2_getattr - Read out an inode's attributes
- * @mnt_userns:	user namespace of the mount the inode was found from
+ * @idmap: idmap of the mount the inode was found from
  * @path: Object to query
  * @stat: The inode's stats
  * @request_mask: Mask of STATX_xxx flags indicating the caller's interests
@@ -2037,7 +2037,7 @@ out:
  * Returns: errno
  */
 
-static int gfs2_getattr(struct user_namespace *mnt_userns,
+static int gfs2_getattr(struct mnt_idmap *idmap,
 			const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int flags)
 {
@@ -2066,7 +2066,7 @@ static int gfs2_getattr(struct user_namespace *mnt_userns,
 				  STATX_ATTR_IMMUTABLE |
 				  STATX_ATTR_NODUMP);
 
-	generic_fillattr(&init_user_ns, inode, stat);
+	generic_fillattr(&nop_mnt_idmap, inode, stat);
 
 	if (gfs2_holder_initialized(&gh))
 		gfs2_glock_dq_uninit(&gh);
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index 0264d514dda7..c8c5814e7295 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -99,7 +99,7 @@ extern int gfs2_inode_refresh(struct gfs2_inode *ip);
 
 extern struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
 				  int is_root);
-extern int gfs2_permission(struct user_namespace *mnt_userns,
+extern int gfs2_permission(struct mnt_idmap *idmap,
 			   struct inode *inode, int mask);
 extern struct inode *gfs2_lookup_simple(struct inode *dip, const char *name);
 extern void gfs2_dinode_out(const struct gfs2_inode *ip, void *buf);
@@ -111,7 +111,7 @@ extern const struct file_operations gfs2_file_fops_nolock;
 extern const struct file_operations gfs2_dir_fops_nolock;
 
 extern int gfs2_fileattr_get(struct dentry *dentry, struct fileattr *fa);
-extern int gfs2_fileattr_set(struct user_namespace *mnt_userns,
+extern int gfs2_fileattr_set(struct mnt_idmap *idmap,
 			     struct dentry *dentry, struct fileattr *fa);
 extern void gfs2_set_inode_flags(struct inode *inode);
  
diff --git a/fs/gfs2/xattr.c b/fs/gfs2/xattr.c
index 518c0677e12a..adf6d17cf033 100644
--- a/fs/gfs2/xattr.c
+++ b/fs/gfs2/xattr.c
@@ -1225,7 +1225,7 @@ int __gfs2_xattr_set(struct inode *inode, const char *name,
 }
 
 static int gfs2_xattr_set(const struct xattr_handler *handler,
-			  struct user_namespace *mnt_userns,
+			  struct mnt_idmap *idmap,
 			  struct dentry *unused, struct inode *inode,
 			  const char *name, const void *value,
 			  size_t size, int flags)