cifs: support nested dfs links over reconnect
Mounting a dfs link that has nested links was already supported at
mount(2), so make it work over reconnect as well.
Make the following case work:
* mount //root/dfs/link /mnt -o ...
- final share: /server/share
* in server settings
- change target folder of /root/dfs/link3 to /server/share2
- change target folder of /root/dfs/link2 to /root/dfs/link3
- change target folder of /root/dfs/link to /root/dfs/link2
* mount -o remount,... /mnt
- refresh all dfs referrals
- mark current connection for failover
- cifs_reconnect() reconnects to root server
- tree_connect()
* checks that /root/dfs/link2 is a link, then chase it
* checks that root/dfs/link3 is a link, then chase it
* finally tree connect to /server/share2
If the mounted share is no longer accessible and a reconnect had been
triggered, the client will retry it from both last referral
path (/root/dfs/link3) and original referral path (/root/dfs/link).
Any new referral paths found while chasing dfs links over reconnect,
it will be updated to TCP_Server_Info::leaf_fullpath, accordingly.
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 5ddbc1a..5c1259d 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -1364,9 +1364,9 @@ static void mark_for_reconnect_if_needed(struct cifs_tcon *tcon, struct dfs_cach
}
/* Refresh dfs referral of tcon and mark it for reconnect if needed */
-static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool force_refresh)
+static int __refresh_tcon(const char *path, struct cifs_ses **sessions, struct cifs_tcon *tcon,
+ bool force_refresh)
{
- const char *path = tcon->dfs_path + 1;
struct cifs_ses *ses;
struct cache_entry *ce;
struct dfs_info3_param *refs = NULL;
@@ -1422,6 +1422,20 @@ static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool
return rc;
}
+static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool force_refresh)
+{
+ struct TCP_Server_Info *server = tcon->ses->server;
+
+ mutex_lock(&server->refpath_lock);
+ if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+ __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh);
+ mutex_unlock(&server->refpath_lock);
+
+ __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh);
+
+ return 0;
+}
+
/**
* dfs_cache_remount_fs - remount a DFS share
*
@@ -1435,6 +1449,7 @@ static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool
int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
{
struct cifs_tcon *tcon;
+ struct TCP_Server_Info *server;
struct mount_group *mg;
struct cifs_ses *sessions[CACHE_MAX_ENTRIES + 1] = {NULL};
int rc;
@@ -1443,13 +1458,15 @@ int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
return -EINVAL;
tcon = cifs_sb_master_tcon(cifs_sb);
- if (!tcon->dfs_path) {
- cifs_dbg(FYI, "%s: not a dfs tcon\n", __func__);
+ server = tcon->ses->server;
+
+ if (!server->origin_fullpath) {
+ cifs_dbg(FYI, "%s: not a dfs mount\n", __func__);
return 0;
}
if (uuid_is_null(&cifs_sb->dfs_mount_id)) {
- cifs_dbg(FYI, "%s: tcon has no dfs mount group id\n", __func__);
+ cifs_dbg(FYI, "%s: no dfs mount group id\n", __func__);
return -EINVAL;
}
@@ -1457,7 +1474,7 @@ int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
mg = find_mount_group_locked(&cifs_sb->dfs_mount_id);
if (IS_ERR(mg)) {
mutex_unlock(&mount_group_list_lock);
- cifs_dbg(FYI, "%s: tcon has ipc session to refresh referral\n", __func__);
+ cifs_dbg(FYI, "%s: no ipc session for refreshing referral\n", __func__);
return PTR_ERR(mg);
}
kref_get(&mg->refcount);
@@ -1498,9 +1515,12 @@ static void refresh_mounts(struct cifs_ses **sessions)
spin_lock(&cifs_tcp_ses_lock);
list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+ if (!server->is_dfs_conn)
+ continue;
+
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
- if (tcon->dfs_path) {
+ if (!tcon->ipc && !tcon->need_reconnect) {
tcon->tc_count++;
list_add_tail(&tcon->ulist, &tcons);
}
@@ -1510,8 +1530,16 @@ static void refresh_mounts(struct cifs_ses **sessions)
spin_unlock(&cifs_tcp_ses_lock);
list_for_each_entry_safe(tcon, ntcon, &tcons, ulist) {
+ struct TCP_Server_Info *server = tcon->ses->server;
+
list_del_init(&tcon->ulist);
- refresh_tcon(sessions, tcon, false);
+
+ mutex_lock(&server->refpath_lock);
+ if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+ __refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false);
+ mutex_unlock(&server->refpath_lock);
+
+ __refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false);
cifs_put_tcon(tcon);
}
}