[PATCH 5.4 17/72] cifs: fix DFS mount with cifsacl/modefromsid

[Greg Kroah-Hartman]

From: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Reviewed-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/cifs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index eb2e3db3916f0..17df90b5f57a2 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -898,6 +898,8 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
 	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);
@@ -906,6 +908,8 @@ cifs_get_inode_info(struct inode **inode, const char *full_path,
 	} 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