Commit 72a8e05d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'ovl-fixes-5.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 

Pull overlayfs fix from Miklos Szeredi:
 "Add a temporary fix for posix acls on idmapped mounts introduced in
  this cycle. A proper fix will be added in the next cycle"

* tag 'ovl-fixes-5.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: turn off SB_POSIXACL with idmapped layers temporarily
parents 29851567 4a47c638

Documentation/filesystems/overlayfs.rst

+4 −0
Original line number Diff line number Diff line
@@ -466,6 +466,10 @@ overlay filesystem and the value of st_ino for filesystem objects may not be 
persistent and could change even while the overlay filesystem is mounted, as

summarized in the `Inode properties`_ table above.



4) "idmapped mounts"

When the upper or lower layers are idmapped mounts overlayfs will be mounted

without support for POSIX Access Control Lists (ACLs). This limitation will

eventually be lifted.



Changes to underlying filesystems

---------------------------------

fs/overlayfs/super.c

+24 −1
Original line number Diff line number Diff line
@@ -1003,6 +1003,9 @@ ovl_posix_acl_xattr_get(const struct xattr_handler *handler, 
			struct dentry *dentry, struct inode *inode,

			const char *name, void *buffer, size_t size)

{

	if (!IS_POSIXACL(inode))

		return -EOPNOTSUPP;



	return ovl_xattr_get(dentry, inode, handler->name, buffer, size);

}
@@ -1018,6 +1021,9 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler, 
	struct posix_acl *acl = NULL;

	int err;



	if (!IS_POSIXACL(inode))

		return -EOPNOTSUPP;



	/* Check that everything is OK before copy-up */

	if (value) {

		acl = posix_acl_from_xattr(&init_user_ns, value, size);
@@ -1960,6 +1966,20 @@ static struct dentry *ovl_get_root(struct super_block *sb, 
	return root;

}



static bool ovl_has_idmapped_layers(struct ovl_fs *ofs)

{



	unsigned int i;

	const struct vfsmount *mnt;



	for (i = 0; i < ofs->numlayer; i++) {

		mnt = ofs->layers[i].mnt;

		if (mnt && is_idmapped_mnt(mnt))

			return true;

	}

	return false;

}



static int ovl_fill_super(struct super_block *sb, void *data, int silent)

{

	struct path upperpath = { };
@@ -2129,6 +2149,9 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
	sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers :

		ovl_trusted_xattr_handlers;

	sb->s_fs_info = ofs;

	if (ovl_has_idmapped_layers(ofs))

		pr_warn("POSIX ACLs are not yet supported with idmapped layers, mounting without ACL support.\n");

	else

		sb->s_flags |= SB_POSIXACL;

	sb->s_iflags |= SB_I_SKIP_SYNC;