From: Paulo Alcantara <pc@cjr.nz>
Date: Tue, 21 Jul 2020 09:36:43 -0300
Subject: [PATCH] cifs: only update prefix path of DFS links in
cifs_tree_connect()
Git-commit: 11375a59a99ca05086a1837c27d79e92dd8d4aed
References: bsc#1144333 bsc#1172428
Patch-mainline: v5.9-rc1
For DFS root mounts that contain a prefix path, do not change them
after failover.
E.g., if the user mounts
//srvA/root/dir1
and then lost connection to srvA, it will reconnect to
//srvB/root/dir1
In case of DFS links, which may resolve to different prefix paths
depending on their list of targets, the following must be supported:
- mount //srvA/root/link/bar
- connect to //srvA/share
- set prefix path to "bar"
- lost connection to srvA
- reconnect to next target: //srvB/share/foo
- set new prefix path to "foo/bar"
In cifs_tree_connect(), check the server_type field of the cached DFS
referral to determine whether or not prefix path should be updated.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/connect.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index aae90953e07f..637ba0066636 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -5548,6 +5548,8 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
const char *dfs_host;
size_t dfs_host_len;
char *share = NULL, *prefix = NULL;
+ struct dfs_info3_param ref = {0};
+ bool isroot;
tree = kzalloc(MAX_TREE_SIZE, GFP_KERNEL);
if (!tree)
@@ -5563,9 +5565,11 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
goto out;
}
- rc = dfs_cache_noreq_find(tcon->dfs_path + 1, NULL, &tl);
+ rc = dfs_cache_noreq_find(tcon->dfs_path + 1, &ref, &tl);
if (rc)
goto out;
+ isroot = ref.server_type == DFS_TYPE_ROOT;
+ free_dfs_info_param(&ref);
extract_unc_hostname(server->hostname, &tcp_host, &tcp_host_len);
@@ -5609,7 +5613,8 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
} else {
scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
- if (!rc) {
+ /* Only handle prefix paths of DFS link targets */
+ if (!rc && !isroot) {
rc = update_super_prepath(tcon, prefix);
break;
}
--
2.28.0