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Commit d377c5eb authored by Miklos Szeredi's avatar Miklos Szeredi
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ovl: don't remove non-empty opaque directory 



When removing an opaque directory we can't just call rmdir() to check for
emptiness, because the directory will need to be replaced with a whiteout.
The replacement is done with RENAME_EXCHANGE, which doesn't check
emptiness.

Solution is just to check emptiness by reading the directory.  In the
future we could add a new rename flag to check for emptiness even for
RENAME_EXCHANGE to optimize this case.

Reported-by: default avatarVincent Batts <vbatts@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Tested-by: default avatarJordi Pujol Palomer <jordipujolp@gmail.com>
Fixes: 263b4a0f ("ovl: dont replace opaque dir")
Cc: <stable@vger.kernel.org> # v4.0+
parent 030bbdbf

fs/overlayfs/dir.c

+19 −5
Original line number Diff line number Diff line
@@ -506,11 +506,25 @@ static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) 
	struct dentry *opaquedir = NULL;

	int err;



	if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {

	if (is_dir) {

		if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {

			opaquedir = ovl_check_empty_and_clear(dentry);

			err = PTR_ERR(opaquedir);

			if (IS_ERR(opaquedir))

				goto out;

		} else {

			LIST_HEAD(list);



			/*

			 * When removing an empty opaque directory, then it

			 * makes no sense to replace it with an exact replica of

			 * itself.  But emptiness still needs to be checked.

			 */

			err = ovl_check_empty_dir(dentry, &list);

			ovl_cache_free(&list);

			if (err)

				goto out;

		}

	}



	err = ovl_lock_rename_workdir(workdir, upperdir);