Commit 07f6fff1 authored Jul 04, 2017 by zhangyi (F) Committed by Miklos Szeredi Nov 09, 2017

ovl: fix rmdir problem on non-merge dir with origin xattr



An "origin && non-merge" upper dir may have leftover whiteouts that
were created in past mount. overlayfs does no clear this dir when we
delete it, which may lead to rmdir fail or temp file left in workdir.

Simple reproducer:
  mkdir lower upper work merge
  mkdir -p lower/dir
  touch lower/dir/a
  mount -t overlay overlay -olowerdir=lower,upperdir=upper,\
    workdir=work merge
  rm merge/dir/a
  umount merge
  rm -rf lower/*
  touch lower/dir  (*)
  mount -t overlay overlay -olowerdir=lower,upperdir=upper,\
    workdir=work merge
  rm -rf merge/dir

Syslog dump:
  overlayfs: cleanup of 'work/#7' failed (-39)

(*): if we do not create the regular file, the result is different:
  rm: cannot remove "dir/": Directory not empty

This patch adds a check for the case of non-merge dir that may contain
whiteouts, and calls ovl_check_empty_dir() to check and clear whiteouts
from upper dir when an empty dir is being deleted.

[amir: split patch from ovl_check_empty_dir() cleanup
       rename ovl_is_origin() to ovl_may_have_whiteouts()
       check OVL_WHITEOUTS flag instead of checking origin xattr]

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

parent 95e598e7

fs/overlayfs/dir.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -181,6 +181,11 @@ static bool ovl_type_origin(struct dentry *dentry)
		return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
		}

		static bool ovl_may_have_whiteouts(struct dentry *dentry)
		{
		return ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
		}

		static int ovl_create_upper(struct dentry dentry, struct inode inode,
		struct cattr attr, struct dentry hardlink)
		{
		@@ -697,8 +702,9 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
		struct dentry *opaquedir = NULL;
		int err;

		/* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */
		if (is_dir && ovl_dentry_get_redirect(dentry)) {
		/* Redirect/origin dir can be !ovl_lower_positive && not clean */
		if (is_dir && (ovl_dentry_get_redirect(dentry) \|\|
		ovl_may_have_whiteouts(dentry))) {
		opaquedir = ovl_check_empty_and_clear(dentry);
		err = PTR_ERR(opaquedir);
		if (IS_ERR(opaquedir))
		@@ -945,7 +951,8 @@ static int ovl_rename(struct inode olddir, struct dentry old,

		old_cred = ovl_override_creds(old->d_sb);

		if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) {
		if (overwrite && new_is_dir && (ovl_type_merge_or_lower(new) \|\|
		ovl_may_have_whiteouts(new))) {
		opaquedir = ovl_check_empty_and_clear(new);
		err = PTR_ERR(opaquedir);
		if (IS_ERR(opaquedir)) {

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