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Commit d1595119 authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
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ovl: check for emptiness of redirect dir 



Before introducing redirect_dir feature, the condition
!ovl_lower_positive(dentry) for a directory, implied that it is a pure
upper directory, which may be removed if empty.

Now that directory can be redirect, it is possible that upper does not
cover any lower (i.e. !ovl_lower_positive(dentry)), but the directory is a
merge (with redirected path) and maybe non empty.

Check for this case in ovl_remove_upper().

This change fixes the following test case from rename-pop-dir.py
of unionmount-testsuite:

    """Remove dir and rename old name"""
    d = ctx.non_empty_dir()
    d2 = ctx.no_dir()

    ctx.rmdir(d, err=ENOTEMPTY)
    ctx.rename(d, d2)
    ctx.rmdir(d, err=ENOENT)
    ctx.rmdir(d2, err=ENOTEMPTY)

./run --ov rename-pop-dir
/mnt/a/no_dir103: Expected error (Directory not empty) was not produced

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent a6c60655

fs/overlayfs/dir.c

+22 −9
Original line number Diff line number Diff line
@@ -674,8 +674,17 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) 
	struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);

	struct inode *dir = upperdir->d_inode;

	struct dentry *upper;

	struct dentry *opaquedir = NULL;

	int err;



	/* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */

	if (is_dir && ovl_dentry_get_redirect(dentry)) {

		opaquedir = ovl_check_empty_and_clear(dentry);

		err = PTR_ERR(opaquedir);

		if (IS_ERR(opaquedir))

			goto out;

	}



	inode_lock_nested(dir, I_MUTEX_PARENT);

	upper = lookup_one_len(dentry->d_name.name, upperdir,

			       dentry->d_name.len);
@@ -684,14 +693,15 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) 
		goto out_unlock;



	err = -ESTALE;

	if (upper == ovl_dentry_upper(dentry)) {

	if ((opaquedir && upper != opaquedir) ||

	    (!opaquedir && upper != ovl_dentry_upper(dentry)))

		goto out_dput_upper;



	if (is_dir)

		err = vfs_rmdir(dir, upper);

	else

		err = vfs_unlink(dir, upper, NULL);

	ovl_dentry_version_inc(dentry->d_parent);

	}

	dput(upper);



	/*

	 * Keeping this dentry hashed would mean having to release
@@ -701,9 +711,12 @@ static int ovl_remove_upper(struct dentry *dentry, bool is_dir) 
	 */

	if (!err)

		d_drop(dentry);

out_dput_upper:

	dput(upper);

out_unlock:

	inode_unlock(dir);



	dput(opaquedir);

out:

	return err;

}