From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 9 Dec 2020 23:38:24 +0000 (-0500)
Subject: fix hostfs_open() use of ->f_path.dentry
X-Git-Tag: microblaze-v5.12~18^2
X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=commitdiff_plain;h=2e2cbaf920d14de9a96180ddefd6861bcc46f07d

fix hostfs_open() use of ->f_path.dentry

this is one of the cases where we need to use d_real() - we are
using more than the name of dentry here.  ->d_sb is used as well,
so in case of hostfs being used as a layer we get the wrong
superblock.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index c070c0d8e3e9..aea35459d390 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -315,7 +315,7 @@ retry:
 	if (mode & FMODE_WRITE)
 		r = w = 1;
 
-	name = dentry_name(file->f_path.dentry);
+	name = dentry_name(d_real(file->f_path.dentry, file->f_inode));
 	if (name == NULL)
 		return -ENOMEM;