Commit 2ba9d57e authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: take mnt_want_write() for work/index dir setup 



There are several write operations on upper fs not covered by
mnt_want_write():

- test set/remove OPAQUE xattr
- test create O_TMPFILE
- set ORIGIN xattr in ovl_verify_origin()
- cleanup of index entries in ovl_indexdir_cleanup()

Some of these go way back, but this patch only applies over the
v4.14 re-factoring of ovl_fill_super().

Cc: <stable@vger.kernel.org> #v4.14
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent f8167817

fs/overlayfs/super.c

+17 −8
Original line number Diff line number Diff line
@@ -521,10 +521,6 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, 
	bool retried = false;

	bool locked = false;



	err = mnt_want_write(mnt);

	if (err)

		goto out_err;



	inode_lock_nested(dir, I_MUTEX_PARENT);

	locked = true;
@@ -589,7 +585,6 @@ retry: 
		goto out_err;

	}

out_unlock:

	mnt_drop_write(mnt);

	if (locked)

		inode_unlock(dir);
@@ -930,12 +925,17 @@ out: 


static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath)

{

	struct vfsmount *mnt = ofs->upper_mnt;

	struct dentry *temp;

	int err;



	err = mnt_want_write(mnt);

	if (err)

		return err;



	ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);

	if (!ofs->workdir)

		return 0;

		goto out;



	/*

	 * Upper should support d_type, else whiteouts are visible.  Given
@@ -945,7 +945,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) 
	 */

	err = ovl_check_d_type_supported(workpath);

	if (err < 0)

		return err;

		goto out;



	/*

	 * We allowed this configuration and don't want to break users over
@@ -969,6 +969,7 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) 
	if (err) {

		ofs->noxattr = true;

		pr_warn("overlayfs: upper fs does not support xattr.\n");

		err = 0;

	} else {

		vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);

	}
@@ -980,7 +981,9 @@ static int ovl_make_workdir(struct ovl_fs *ofs, struct path *workpath) 
		pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n");

	}



	return 0;

out:

	mnt_drop_write(mnt);

	return err;

}



static int ovl_get_workdir(struct ovl_fs *ofs, struct path *upperpath)
@@ -1027,8 +1030,13 @@ out: 
static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe,

			    struct path *upperpath)

{

	struct vfsmount *mnt = ofs->upper_mnt;

	int err;



	err = mnt_want_write(mnt);

	if (err)

		return err;



	/* Verify lower root is upper root origin */

	err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry,

				false, true);
@@ -1056,6 +1064,7 @@ static int ovl_get_indexdir(struct ovl_fs *ofs, struct ovl_entry *oe, 
		pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");



out:

	mnt_drop_write(mnt);

	return err;

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE