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ovl: Fix opaque regression in ovl_lookup

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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>
This commit is contained in:
hujianyang 2015-01-06 16:10:01 +08:00 committed by Miklos Szeredi
parent 2f83fd8c28
commit a425c037f3
1 changed files with 13 additions and 10 deletions
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23
fs/overlayfs/super.c
View file

@ -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 this is a non-directory then stop here.
*
* FIXME: check for 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 && (!S_ISDIR(prev->d_inode->i_mode) ||
!S_ISDIR(this->d_inode->i_mode))) {
/*
* FIXME: check for upper-opaqueness maybe better done
* in remove code.
*/
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++;