From: Paulo Alcantara <paulo@xxxxxxxx>
After failing to reconnect to original target, it will retry any
target available from DFS cache.
Signed-off-by: Paulo Alcantara <palcantara@xxxxxxx>
Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
---
fs/cifs/cifs_fs_sb.h | 9 +++
fs/cifs/cifsglob.h | 7 ++
fs/cifs/connect.c | 189 ++++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 204 insertions(+), 1 deletion(-)
diff --git a/fs/cifs/cifs_fs_sb.h b/fs/cifs/cifs_fs_sb.h
index 63d7530f2e1d..42f0d67f1054 100644
--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -72,6 +72,15 @@ struct cifs_sb_info {
char *mountdata; /* options received at mount time or via DFS refs */
struct delayed_work prune_tlinks;
struct rcu_head rcu;
+
+ /* only used when CIFS_MOUNT_USE_PREFIX_PATH is set */
char *prepath;
+
+ /*
+ * Path initially provided by the mount call. We might connect
+ * to something different via DFS but we want to keep it to do
+ * failover properly.
+ */
+ char *origin_fullpath; /* \\HOST\SHARE\[OPTIONAL PATH] */
};
#endif /* _CIFS_FS_SB_H */
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 60c202bbcdfc..643633a3dc09 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -701,6 +701,13 @@ struct TCP_Server_Info {
struct delayed_work reconnect; /* reconnect workqueue job */
struct mutex reconnect_mutex; /* prevent simultaneous reconnects */
unsigned long echo_interval;
+
+ /*
+ * Number of targets available for reconnect. The more targets
+ * the more tasks have to wait to let the demultiplex thread
+ * reconnect.
+ */
+ int nr_targets;
};
static inline unsigned int
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index c4ce52818ed6..52d837d7bf57 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -57,6 +57,7 @@
#include "smb2proto.h"
#include "smbdirect.h"
#include "dns_resolve.h"
+#include "cifsfs.h"
#ifdef CONFIG_CIFS_DFS_UPCALL
#include "dfs_cache.h"
#endif
@@ -321,6 +322,115 @@ static void tlink_rb_insert(struct rb_root *root, struct tcon_link *new_tlink);
static void cifs_prune_tlinks(struct work_struct *work);
static int cifs_setup_volume_info(struct smb_vol *volume_info, char *mount_data,
const char *devname, bool is_smb3);
+static char *extract_hostname(const char *unc);
+
+#ifdef CONFIG_CIFS_DFS_UPCALL
+struct super_cb_data {
+ struct TCP_Server_Info *server;
+ struct cifs_sb_info *cifs_sb;
+};
+
+/* These functions must be called with server->srv_mutex held */
+
+static void super_cb(struct super_block *sb, void *arg)
+{
+ struct super_cb_data *d = arg;
+ struct cifs_sb_info *cifs_sb;
+ struct cifs_tcon *tcon;
+
+ if (d->cifs_sb)
+ return;
+
+ cifs_sb = CIFS_SB(sb);
+ tcon = cifs_sb_master_tcon(cifs_sb);
+ if (tcon->ses->server == d->server)
+ d->cifs_sb = cifs_sb;
+}
+
+static inline struct cifs_sb_info *
+find_super_by_tcp(struct TCP_Server_Info *server)
+{
+ struct super_cb_data d = {
+ .server = server,
+ .cifs_sb = NULL,
+ };
+
+ iterate_supers_type(&cifs_fs_type, super_cb, &d);
+ return d.cifs_sb ? d.cifs_sb : ERR_PTR(-ENOENT);
+}
+
+static void reconn_inval_dfs_target(struct TCP_Server_Info *server,
+ struct cifs_sb_info *cifs_sb,
+ struct dfs_cache_tgt_list *tgt_list,
+ struct dfs_cache_tgt_iterator **tgt_it)
+{
+ const char *name;
+ int rc;
+ char *ipaddr = NULL;
+ char *unc;
+ int len;
+
+ if (!cifs_sb->origin_fullpath || !tgt_list || !server->nr_targets)
+ return;
+
+ if (!*tgt_it) {
+ *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
+ } else {
+ *tgt_it = dfs_cache_get_next_tgt(tgt_list, *tgt_it);
+ if (!*tgt_it)
+ *tgt_it = dfs_cache_get_tgt_iterator(tgt_list);
+ }
+
+ cifs_dbg(FYI, "%s: UNC: %s\n", __func__, cifs_sb->origin_fullpath);
+
+ name = dfs_cache_get_tgt_name(*tgt_it);
+
+ kfree(server->hostname);
+
+ server->hostname = extract_hostname(name);
+ if (!server->hostname) {
+ cifs_dbg(FYI, "%s: failed to extract hostname from target: %d\n",
+ __func__, -ENOMEM);
+ return;
+ }
+
+ len = strlen(server->hostname) + 3;
+
+ unc = kmalloc(len, GFP_KERNEL);
+ if (!unc) {
+ cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__);
+ return;
+ }
+ snprintf(unc, len, "\\\\%s", server->hostname);
+
+ rc = dns_resolve_server_name_to_ip(unc, &ipaddr);
+ kfree(unc);
+
+ if (rc < 0) {
+ cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",
+ __func__, server->hostname, rc);
+ return;
+ }
+
+ rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
+ strlen(ipaddr));
+ kfree(ipaddr);
+
+ if (!rc) {
+ cifs_dbg(FYI, "%s: failed to get ipaddr out of hostname\n",
+ __func__);
+ }
+}
+
+static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
+ struct dfs_cache_tgt_list *tl,
+ struct dfs_cache_tgt_iterator **it)
+{
+ if (!cifs_sb->origin_fullpath)
+ return -EOPNOTSUPP;
+ return dfs_cache_noreq_find(cifs_sb->origin_fullpath + 1, NULL, tl);
+}
+#endif
/*
* cifs tcp session reconnection
@@ -339,8 +449,34 @@ cifs_reconnect(struct TCP_Server_Info *server)
struct cifs_tcon *tcon;
struct mid_q_entry *mid_entry;
struct list_head retry_list;
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ struct cifs_sb_info *cifs_sb;
+ struct dfs_cache_tgt_list tgt_list;
+ struct dfs_cache_tgt_iterator *tgt_it = NULL;
+#endif
spin_lock(&GlobalMid_Lock);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ cifs_sb = find_super_by_tcp(server);
+ if (IS_ERR(cifs_sb)) {
+ rc = PTR_ERR(cifs_sb);
+ } else {
+ rc = reconn_setup_dfs_targets(cifs_sb, &tgt_list, &tgt_it);
+ if (rc) {
+ cifs_dbg(VFS, "%s: no target servers for DFS failover\n",
+ __func__);
+ }
+ }
+ if (!rc) {
+ server->nr_targets = dfs_cache_get_nr_tgts(&tgt_list);
+ } else {
+ server->nr_targets = 1;
+ cifs_dbg(VFS, "%s: will not do DFS failover: rc = %d\n",
+ __func__, rc);
+ }
+ cifs_dbg(FYI, "%s: will retry %d target(s)\n", __func__,
+ server->nr_targets);
+#endif
if (server->tcpStatus == CifsExiting) {
/* the demux thread will exit normally
next time through the loop */
@@ -414,14 +550,22 @@ cifs_reconnect(struct TCP_Server_Info *server)
do {
try_to_freeze();
- /* we should try only the port we connected to before */
mutex_lock(&server->srv_mutex);
+ /*
+ * Set up next DFS target server (if any) for reconnect. If DFS
+ * feature is disabled, then we will retry last server we
+ * connected to before.
+ */
if (cifs_rdma_enabled(server))
rc = smbd_reconnect(server);
else
rc = generic_ip_connect(server);
if (rc) {
cifs_dbg(FYI, "reconnect error %d\n", rc);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ reconn_inval_dfs_target(server, cifs_sb, &tgt_list,
+ &tgt_it);
+#endif
mutex_unlock(&server->srv_mutex);
msleep(3000);
} else {
@@ -434,6 +578,22 @@ cifs_reconnect(struct TCP_Server_Info *server)
}
} while (server->tcpStatus == CifsNeedReconnect);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ if (tgt_it) {
+ rc = dfs_cache_noreq_update_tgthint(cifs_sb->origin_fullpath + 1,
+ tgt_it);
+ if (rc) {
+ cifs_dbg(VFS, "%s: failed to update DFS target hint: rc = %d\n",
+ __func__, rc);
+ }
+ rc = dfs_cache_update_vol(cifs_sb->origin_fullpath, server);
+ if (rc) {
+ cifs_dbg(VFS, "%s: failed to update vol info in DFS cache: rc = %d\n",
+ __func__, rc);
+ }
+ }
+ dfs_cache_free_tgts(&tgt_list);
+#endif
if (server->tcpStatus == CifsNeedNegotiate)
mod_delayed_work(cifsiod_wq, &server->echo, 0);
@@ -2470,6 +2630,8 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
}
tcp_ses->tcpStatus = CifsNeedNegotiate;
+ tcp_ses->nr_targets = 1;
+
/* thread spawned, put it on the list */
spin_lock(&cifs_tcp_ses_lock);
list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
@@ -4291,6 +4453,12 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
goto error;
}
+ full_path = build_unc_path_to_root(vol, cifs_sb, true);
+ if (IS_ERR(full_path)) {
+ rc = PTR_ERR(full_path);
+ full_path = NULL;
+ goto error;
+ }
/*
* Perform an unconditional check for whether there are DFS
* referrals for this path without prefix, to provide support
@@ -4397,6 +4565,22 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb_vol *vol)
if (rc)
goto error;
+ spin_lock(&cifs_tcp_ses_lock);
+ if (!tcon->dfs_path) {
+ /* Save full path in new tcon to do failover when reconnecting tcons */
+ tcon->dfs_path = full_path;
+ full_path = NULL;
+ tcon->remap = cifs_remap(cifs_sb);
+ }
+ cifs_sb->origin_fullpath = kstrndup(tcon->dfs_path,
+ strlen(tcon->dfs_path), GFP_KERNEL);
+ if (!cifs_sb->origin_fullpath) {
+ spin_unlock(&cifs_tcp_ses_lock);
+ rc = -ENOMEM;
+ goto error;
+ }
+ spin_unlock(&cifs_tcp_ses_lock);
+
/*
* After reconnecting to a different server, unique ids won't
* match anymore, so we disable serverino. This prevents
@@ -4638,6 +4822,9 @@ cifs_umount(struct cifs_sb_info *cifs_sb)
kfree(cifs_sb->mountdata);
kfree(cifs_sb->prepath);
+#ifdef CONFIG_CIFS_DFS_UPCALL
+ kfree(cifs_sb->origin_fullpath);
+#endif
call_rcu(&cifs_sb->rcu, delayed_free);
}
--
2.13.7
