ovl: Fix opaque regression in ovl_lookup (a425c037) · Commits · 戴 / test

Current multi-layer support overlayfs has a regression in .lookup(). If there is a directory in upperdir and a regular file has same name in lowerdir in a merged directory, lower file is hidden and upper directory is set to opaque in former case. But it is changed in present code. In lowerdir lookup path, if a found inode is not directory, the type checking of previous inode is missing. This inode will be copied to the lowerstack of ovl_entry directly. That will lead to several wrong conditions, for example, the reading of the directory in upperdir may return an error like: ls: reading directory .: Not a directory This patch makes the lowerdir lookup path check the opaque for non-directory file too. Signed-off-by:

hujianyang <hujianyang@huawei.com> Signed-off-by:

Miklos Szeredi <mszeredi@suse.cz>

fs/overlayfs/super.c

+13 −10

Original line number	Diff line number	Diff line
		@@ -372,7 +372,6 @@ struct dentry ovl_lookup(struct inode dir, struct dentry *dentry,
		bool opaque = false;
		struct path lowerpath = poe->lowerstack[i];

		opaque = false;
		this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
		err = PTR_ERR(this);
		if (IS_ERR(this)) {
		@@ -395,20 +394,24 @@ struct dentry ovl_lookup(struct inode dir, struct dentry *dentry,
		*/
		if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
		opaque = true;

		if (prev && (!S_ISDIR(prev->d_inode->i_mode) \|\|
		!S_ISDIR(this->d_inode->i_mode))) {
		/*
		* If this is a non-directory then stop here.
		*
		* FIXME: check for opaqueness maybe better done in remove code.
		* FIXME: check for upper-opaqueness maybe better done
		* in remove code.
		*/
		if (!S_ISDIR(this->d_inode->i_mode)) {
		opaque = true;
		} else if (prev && (!S_ISDIR(prev->d_inode->i_mode) \|\|
		!S_ISDIR(this->d_inode->i_mode))) {
		if (prev == upperdentry)
		upperopaque = true;
		dput(this);
		break;
		}
		/*
		* If this is a non-directory then stop here.
		*/
		if (!S_ISDIR(this->d_inode->i_mode))
		opaque = true;

		stack[ctr].dentry = this;
		stack[ctr].mnt = lowerpath.mnt;
		ctr++;

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