[PATCH v3 02/11] cifs: Fix lookup of root ses in DFS referral cache

Paulo Alcantara (SUSE)
2019-11-27T00:37:12Z

We don't care about module aliasing validation in
cifs_compose_mount_options(..., is_smb3) when finding the root SMB
session of an DFS namespace in order to refresh DFS referral cache.

The following issue has been observed when mounting with '-t smb3' and
then specifying 'vers=2.0':

...
Nov 08 15:27:08 tw kernel: address conversion returned 0 for FS0.WIN.LOCAL
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_query((null),FS0.WIN.LOCAL,13,(null))
Nov 08 15:27:08 tw kernel: [kworke] call request_key(,FS0.WIN.LOCAL,)
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_resolver_cmp(FS0.WIN.LOCAL,FS0.WIN.LOCAL)
Nov 08 15:27:08 tw kernel: [kworke] <== dns_resolver_cmp() = 1
Nov 08 15:27:08 tw kernel: [kworke] <== dns_query() = 13
Nov 08 15:27:08 tw kernel: fs/cifs/dns_resolve.c: dns_resolve_server_name_to_ip: resolved: FS0.WIN.LOCAL to 192.168.30.26
===> Nov 08 15:27:08 tw kernel: CIFS VFS: vers=2.0 not permitted when mounting with smb3
Nov 08 15:27:08 tw kernel: fs/cifs/dfs_cache.c: CIFS VFS: leaving refresh_tcon (xid = 26) rc = -22
...

Fixes: 5072010ccf05 ("cifs: Fix DFS cache refresher for DFS links")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
---
fs/cifs/dfs_cache.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 1692c0c6c23a..2faa05860a48 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -1317,7 +1317,6 @@ static struct cifs_ses *find_root_ses(struct dfs_cache_vol_info *vi,
int rc;
struct dfs_info3_param ref = {0};
char *mdata = NULL, *devname = NULL;
- bool is_smb3 = tcon->ses->server->vals->header_preamble_size == 0;
struct TCP_Server_Info *server;
struct cifs_ses *ses;
struct smb_vol vol;
@@ -1344,7 +1343,7 @@ static struct cifs_ses *find_root_ses(struct dfs_cache_vol_info *vi,
goto out;
}

- rc = cifs_setup_volume_info(&vol, mdata, devname, is_smb3);
+ rc = cifs_setup_volume_info(&vol, mdata, devname, false);
kfree(devname);

if (rc) {
--
2.24.0