Commit 53a08cb9 authored by Miklos Szeredi's avatar Miklos Szeredi
Browse files

ovl: make upperdir optional 



Make "upperdir=" mount option optional.  If "upperdir=" is not given, then
the "workdir=" option is also optional (and ignored if given).

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent ab508822

fs/overlayfs/super.c

+47 −36
Original line number Diff line number Diff line
@@ -516,8 +516,10 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) 
	struct ovl_fs *ufs = sb->s_fs_info;



	seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);

	if (ufs->config.upperdir) {

		seq_printf(m, ",upperdir=%s", ufs->config.upperdir);

		seq_printf(m, ",workdir=%s", ufs->config.workdir);

	}

	return 0;

}
@@ -768,8 +770,8 @@ static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) 
static int ovl_fill_super(struct super_block *sb, void *data, int silent)

{

	struct path lowerpath;

	struct path upperpath;

	struct path workpath;

	struct path upperpath = { NULL, NULL };

	struct path workpath = { NULL, NULL };

	struct dentry *root_dentry;

	struct ovl_entry *oe;

	struct ovl_fs *ufs;
@@ -786,11 +788,17 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
	if (err)

		goto out_free_config;



	/* FIXME: workdir is not needed for a R/O mount */

	err = -EINVAL;

	if (!ufs->config.upperdir || !ufs->config.lowerdir ||

	    !ufs->config.workdir) {

		pr_err("overlayfs: missing upperdir or lowerdir or workdir\n");

	if (!ufs->config.lowerdir) {

		pr_err("overlayfs: missing 'lowerdir'\n");

		goto out_free_config;

	}



	sb->s_stack_depth = 0;

	if (ufs->config.upperdir) {

		/* FIXME: workdir is not needed for a R/O mount */

		if (!ufs->config.workdir) {

			pr_err("overlayfs: missing 'workdir'\n");

			goto out_free_config;

		}
@@ -811,6 +819,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
			goto out_put_workpath;

		}

		sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;

	}



	err = ovl_lower_dir(ufs->config.lowerdir, &lowerpath,

			    &ufs->lower_namelen, &sb->s_stack_depth);
@@ -824,6 +833,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
		goto out_put_lowerpath;

	}



	if (ufs->config.upperdir) {

		ufs->upper_mnt = clone_private_mount(&upperpath);

		err = PTR_ERR(ufs->upper_mnt);

		if (IS_ERR(ufs->upper_mnt)) {
@@ -838,6 +848,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
			       ufs->config.workdir, OVL_WORKDIR_NAME);

			goto out_put_upper_mnt;

		}

	}



	ufs->lower_mnt = kcalloc(1, sizeof(struct vfsmount *), GFP_KERNEL);

	if (ufs->lower_mnt == NULL)
@@ -858,8 +869,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) 
	ufs->lower_mnt[0] = mnt;

	ufs->numlower = 1;



	/* If the upper fs is r/o, we mark overlayfs r/o too */

	if (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)

	/* If the upper fs is r/o or nonexistent, we mark overlayfs r/o too */

	if (!ufs->upper_mnt || (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY))

		sb->s_flags |= MS_RDONLY;



	sb->s_d_op = &ovl_dentry_operations;