From 11375a59a99ca05086a1837c27d79e92dd8d4aed Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Tue, 21 Jul 2020 09:36:43 -0300 Subject: [PATCH] cifs: only update prefix path of DFS links in cifs_tree_connect() 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) Reviewed-by: Aurelien Aptel Signed-off-by: Steve French --- 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; }