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

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>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index e4bcb2cf055a..bfd95bf38005 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);
 }