From: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Date: Tue, 25 Jun 2013 09:03:56 +0000 (+0530)
Subject: pstore: Fail to unlink if a driver has not defined pstore_erase
X-Git-Tag: firefly_0821_release~3679^2~864
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=841eb01f53cdb78d840dc4000f103fa7dd4228d2;p=firefly-linux-kernel-4.4.55.git

pstore: Fail to unlink if a driver has not defined pstore_erase

commit bf2883339a33b7544b92ea465b90c3de55082032 upstream.

pstore_erase is used to erase the record from the persistent store.
So if a driver has not defined pstore_erase callback return
-EPERM instead of unlinking a file as deleting the file without
erasing its record in persistent store will give a wrong impression
to customers.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Cc: HuKeping <hukeping@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 3ba30825f387..eaba02d951d3 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -178,6 +178,8 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
 	if (p->psi->erase)
 		p->psi->erase(p->type, p->id, p->count,
 			      dentry->d_inode->i_ctime, p->psi);
+	else
+		return -EPERM;
 
 	return simple_unlink(dir, dentry);
 }