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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ronnie Sahlberg <lsahlber@redhat.com>,
        "Paulo Alcantara (SUSE)" <pc@cjr.nz>,
        Steve French <stfrench@microsoft.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 024/118] cifs: fix DFS mount with cifsacl/modefromsid
Date:   Mon, 21 Sep 2020 18:27:16 +0200
Message-Id: <20200921162037.431371116@linuxfoundation.org>
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From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit 01ec372cef1e5afa4ab843bbaf88a6fcb64dc14c ]

RHBZ: 1871246

If during cifs_lookup()/get_inode_info() we encounter a DFS link
and we use the cifsacl or modefromsid mount options we must suppress
any -EREMOTE errors that triggers or else we will not be able to follow
the DFS link and automount the target.

This fixes an issue with modefromsid/cifsacl where these mountoptions
would break DFS and we would no longer be able to access the share.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ce95801e9b664..7708175062eba 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1017,6 +1017,8 @@ handle_mnt_opt:
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID) {
 		rc = cifs_acl_to_fattr(cifs_sb, &fattr, *inode, true,
 				       full_path, fid);
+		if (rc == -EREMOTE)
+			rc = 0;
 		if (rc) {
 			cifs_dbg(FYI, "%s: Get mode from SID failed. rc=%d\n",
 				 __func__, rc);
@@ -1025,6 +1027,8 @@ handle_mnt_opt:
 	} else if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) {
 		rc = cifs_acl_to_fattr(cifs_sb, &fattr, *inode, false,
 				       full_path, fid);
+		if (rc == -EREMOTE)
+			rc = 0;
 		if (rc) {
 			cifs_dbg(FYI, "%s: Getting ACL failed with error: %d\n",
 				 __func__, rc);
-- 
2.25.1