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Commit a425c037 authored by hujianyang's avatar hujianyang Committed by Miklos Szeredi
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ovl: Fix opaque regression in ovl_lookup 



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: default avatarhujianyang <hujianyang@huawei.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
parent 2f83fd8c

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++;