1 files changed, 85 insertions, 253 deletions

diff --git a/fs/smb/client/dfs.c b/fs/smb/client/dfs.c
index 3ec965547e3d..f65a8a90ba27 100644
--- a/fs/smb/client/dfs.c
+++ b/fs/smb/client/dfs.c
@@ -9,6 +9,8 @@
 #include "fs_context.h"
 #include "dfs.h"
 
+#define DFS_DOM(ctx) (ctx->dfs_root_ses ? ctx->dfs_root_ses->dns_dom : NULL)
+
 /**
  * dfs_parse_target_referral - set fs context for dfs target referral
  *
@@ -46,8 +48,8 @@ int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_para
 	if (rc)
 		goto out;
 
-	rc = dns_resolve_server_name_to_ip(path, (struct sockaddr *)&ctx->dstaddr, NULL);
-
+	rc = dns_resolve_unc(DFS_DOM(ctx), path,
+			     (struct sockaddr *)&ctx->dstaddr);
 out:
 	kfree(path);
 	return rc;
@@ -59,8 +61,9 @@ static int get_session(struct cifs_mount_ctx *mnt_ctx, const char *full_path)
 	int rc;
 
 	ctx->leaf_fullpath = (char *)full_path;
+	ctx->dns_dom = DFS_DOM(ctx);
 	rc = cifs_mount_get_session(mnt_ctx);
-	ctx->leaf_fullpath = NULL;
+	ctx->leaf_fullpath = ctx->dns_dom = NULL;
 
 	return rc;
 }
@@ -69,7 +72,7 @@ static int get_session(struct cifs_mount_ctx *mnt_ctx, const char *full_path)
  * Get an active reference of @ses so that next call to cifs_put_tcon() won't
  * release it as any new DFS referrals must go through its IPC tcon.
  */
-static void add_root_smb_session(struct cifs_mount_ctx *mnt_ctx)
+static void set_root_smb_session(struct cifs_mount_ctx *mnt_ctx)
 {
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 	struct cifs_ses *ses = mnt_ctx->ses;
@@ -95,15 +98,16 @@ static inline int parse_dfs_target(struct smb3_fs_context *ctx,
 	return rc;
 }
 
-static int set_ref_paths(struct cifs_mount_ctx *mnt_ctx,
-			 struct dfs_info3_param *tgt,
-			 struct dfs_ref_walk *rw)
+static int setup_dfs_ref(struct dfs_info3_param *tgt, struct dfs_ref_walk *rw)
 {
-	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
-	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+	struct cifs_sb_info *cifs_sb = rw->mnt_ctx->cifs_sb;
+	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;
 	char *ref_path, *full_path;
 	int rc;
 
+	set_root_smb_session(rw->mnt_ctx);
+	ref_walk_ses(rw) = ctx->dfs_root_ses;
+
 	full_path = smb3_fs_context_fullpath(ctx, CIFS_DIR_SEP(cifs_sb));
 	if (IS_ERR(full_path))
 		return PTR_ERR(full_path);
@@ -120,34 +124,22 @@ static int set_ref_paths(struct cifs_mount_ctx *mnt_ctx,
 	}
 	ref_walk_path(rw) = ref_path;
 	ref_walk_fpath(rw) = full_path;
-	return 0;
+
+	return dfs_get_referral(rw->mnt_ctx,
+				ref_walk_path(rw) + 1,
+				ref_walk_tl(rw));
 }
 
-static int __dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx,
-			       struct dfs_ref_walk *rw)
+static int __dfs_referral_walk(struct dfs_ref_walk *rw)
 {
-	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;
+	struct cifs_mount_ctx *mnt_ctx = rw->mnt_ctx;
 	struct dfs_info3_param tgt = {};
-	bool is_refsrv;
 	int rc = -ENOENT;
 
 again:
 	do {
-		if (ref_walk_empty(rw)) {
-			rc = dfs_get_referral(mnt_ctx, ref_walk_path(rw) + 1,
-					      NULL, ref_walk_tl(rw));
-			if (rc) {
-				rc = cifs_mount_get_tcon(mnt_ctx);
-				if (!rc)
-					rc = cifs_is_path_remote(mnt_ctx);
-				continue;
-			}
-			if (!ref_walk_num_tgts(rw)) {
-				rc = -ENOENT;
-				continue;
-			}
-		}
-
+		ctx->dfs_root_ses = ref_walk_ses(rw);
 		while (ref_walk_next_tgt(rw)) {
 			rc = parse_dfs_target(ctx, rw, &tgt);
 			if (rc)
@@ -158,55 +150,51 @@ again:
 			if (rc)
 				continue;
 
-			is_refsrv = tgt.server_type == DFS_TYPE_ROOT ||
-				DFS_INTERLINK(tgt.flags);
-			ref_walk_set_tgt_hint(rw);
-
-			if (tgt.flags & DFSREF_STORAGE_SERVER) {
-				rc = cifs_mount_get_tcon(mnt_ctx);
-				if (!rc)
-					rc = cifs_is_path_remote(mnt_ctx);
-				if (!rc)
+			rc = cifs_mount_get_tcon(mnt_ctx);
+			if (rc) {
+				if (tgt.server_type == DFS_TYPE_LINK &&
+				    DFS_INTERLINK(tgt.flags))
+					rc = -EREMOTE;
+			} else {
+				rc = cifs_is_path_remote(mnt_ctx);
+				if (!rc) {
+					ref_walk_set_tgt_hint(rw);
 					break;
-				if (rc != -EREMOTE)
-					continue;
+				}
 			}
-
-			if (is_refsrv)
-				add_root_smb_session(mnt_ctx);
-
-			rc = ref_walk_advance(rw);
-			if (!rc) {
-				rc = set_ref_paths(mnt_ctx, &tgt, rw);
+			if (rc == -EREMOTE) {
+				rc = ref_walk_advance(rw);
 				if (!rc) {
-					rc = -EREMOTE;
+					rc = setup_dfs_ref(&tgt, rw);
+					if (rc)
+						break;
+					ref_walk_mark_end(rw);
 					goto again;
 				}
 			}
-			if (rc != -ELOOP)
-				goto out;
 		}
 	} while (rc && ref_walk_descend(rw));
 
-out:
 	free_dfs_info_param(&tgt);
 	return rc;
 }
 
-static int dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx)
+static int dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx,
+			     struct dfs_ref_walk **rw)
 {
-	struct dfs_ref_walk *rw;
 	int rc;
 
-	rw = ref_walk_alloc();
-	if (IS_ERR(rw))
-		return PTR_ERR(rw);
+	*rw = ref_walk_alloc();
+	if (IS_ERR(*rw)) {
+		rc = PTR_ERR(*rw);
+		*rw = NULL;
+		return rc;
+	}
 
-	ref_walk_init(rw);
-	rc = set_ref_paths(mnt_ctx, NULL, rw);
+	ref_walk_init(*rw, mnt_ctx);
+	rc = setup_dfs_ref(NULL, *rw);
 	if (!rc)
-		rc = __dfs_referral_walk(mnt_ctx, rw);
-	ref_walk_free(rw);
+		rc = __dfs_referral_walk(*rw);
 	return rc;
 }
 
@@ -214,16 +202,16 @@ static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 {
 	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
+	struct dfs_ref_walk *rw = NULL;
 	struct cifs_tcon *tcon;
 	char *origin_fullpath;
-	bool new_tcon = true;
 	int rc;
 
 	origin_fullpath = dfs_get_path(cifs_sb, ctx->source);
 	if (IS_ERR(origin_fullpath))
 		return PTR_ERR(origin_fullpath);
 
-	rc = dfs_referral_walk(mnt_ctx);
+	rc = dfs_referral_walk(mnt_ctx, &rw);
 	if (!rc) {
 		/*
 		 * Prevent superblock from being created with any missing
@@ -241,21 +229,16 @@ static int __dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 
 	tcon = mnt_ctx->tcon;
 	spin_lock(&tcon->tc_lock);
-	if (!tcon->origin_fullpath) {
-		tcon->origin_fullpath = origin_fullpath;
-		origin_fullpath = NULL;
-	} else {
-		new_tcon = false;
-	}
+	tcon->origin_fullpath = origin_fullpath;
+	origin_fullpath = NULL;
+	ref_walk_set_tcon(rw, tcon);
 	spin_unlock(&tcon->tc_lock);
-
-	if (new_tcon) {
-		queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
-				   dfs_cache_get_ttl() * HZ);
-	}
+	queue_delayed_work(dfscache_wq, &tcon->dfs_cache_work,
+			   dfs_cache_get_ttl() * HZ);
 
 out:
 	kfree(origin_fullpath);
+	ref_walk_free(rw);
 	return rc;
 }
 
@@ -271,7 +254,7 @@ static int update_fs_context_dstaddr(struct smb3_fs_context *ctx)
 	int rc = 0;
 
 	if (!ctx->nodfs && ctx->dfs_automount) {
-		rc = dns_resolve_server_name_to_ip(ctx->source, addr, NULL);
+		rc = dns_resolve_unc(NULL, ctx->source, addr);
 		if (!rc)
 			cifs_set_port(addr, ctx->port);
 		ctx->dfs_automount = false;
@@ -279,7 +262,7 @@ static int update_fs_context_dstaddr(struct smb3_fs_context *ctx)
 	return rc;
 }
 
-int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
+int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx)
 {
 	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;
 	bool nodfs = ctx->nodfs;
@@ -289,7 +272,6 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
 	if (rc)
 		return rc;
 
-	*isdfs = false;
 	rc = get_session(mnt_ctx, NULL);
 	if (rc)
 		return rc;
@@ -302,7 +284,7 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
 	 * to respond with PATH_NOT_COVERED to requests that include the prefix.
 	 */
 	if (!nodfs) {
-		rc = dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL, NULL);
+		rc = dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL);
 		if (rc) {
 			cifs_dbg(FYI, "%s: no dfs referral for %s: %d\n",
 				 __func__, ctx->UNC + 1, rc);
@@ -317,53 +299,13 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs)
 		return rc;
 	}
 
-	*isdfs = true;
-	add_root_smb_session(mnt_ctx);
-	rc = __dfs_mount_share(mnt_ctx);
-	dfs_put_root_smb_sessions(mnt_ctx);
-	return rc;
-}
-
-/* Update dfs referral path of superblock */
-static int update_server_fullpath(struct TCP_Server_Info *server, struct cifs_sb_info *cifs_sb,
-				  const char *target)
-{
-	int rc = 0;
-	size_t len = strlen(target);
-	char *refpath, *npath;
-
-	if (unlikely(len < 2 || *target != '\\'))
-		return -EINVAL;
-
-	if (target[1] == '\\') {
-		len += 1;
-		refpath = kmalloc(len, GFP_KERNEL);
-		if (!refpath)
-			return -ENOMEM;
-
-		scnprintf(refpath, len, "%s", target);
-	} else {
-		len += sizeof("\\");
-		refpath = kmalloc(len, GFP_KERNEL);
-		if (!refpath)
-			return -ENOMEM;
-
-		scnprintf(refpath, len, "\\%s", target);
-	}
-
-	npath = dfs_cache_canonical_path(refpath, cifs_sb->local_nls, cifs_remap(cifs_sb));
-	kfree(refpath);
-
-	if (IS_ERR(npath)) {
-		rc = PTR_ERR(npath);
-	} else {
-		mutex_lock(&server->refpath_lock);
-		spin_lock(&server->srv_lock);
-		kfree(server->leaf_fullpath);
-		server->leaf_fullpath = npath;
-		spin_unlock(&server->srv_lock);
-		mutex_unlock(&server->refpath_lock);
+	if (!ctx->dfs_conn) {
+		ctx->dfs_conn = true;
+		cifs_mount_put_conns(mnt_ctx);
+		rc = get_session(mnt_ctx, NULL);
 	}
+	if (!rc)
+		rc = __dfs_mount_share(mnt_ctx);
 	return rc;
 }
 
@@ -391,77 +333,22 @@ static int target_share_matches_server(struct TCP_Server_Info *server, char *sha
 	return rc;
 }
 
-static void __tree_connect_ipc(const unsigned int xid, char *tree,
-			       struct cifs_sb_info *cifs_sb,
-			       struct cifs_ses *ses)
-{
-	struct TCP_Server_Info *server = ses->server;
-	struct cifs_tcon *tcon = ses->tcon_ipc;
-	int rc;
-
-	spin_lock(&ses->ses_lock);
-	spin_lock(&ses->chan_lock);
-	if (cifs_chan_needs_reconnect(ses, server) ||
-	    ses->ses_status != SES_GOOD) {
-		spin_unlock(&ses->chan_lock);
-		spin_unlock(&ses->ses_lock);
-		cifs_server_dbg(FYI, "%s: skipping ipc reconnect due to disconnected ses\n",
-				__func__);
-		return;
-	}
-	spin_unlock(&ses->chan_lock);
-	spin_unlock(&ses->ses_lock);
-
-	cifs_server_lock(server);
-	scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
-	cifs_server_unlock(server);
-
-	rc = server->ops->tree_connect(xid, ses, tree, tcon,
-				       cifs_sb->local_nls);
-	cifs_server_dbg(FYI, "%s: tree_reconnect %s: %d\n", __func__, tree, rc);
-	spin_lock(&tcon->tc_lock);
-	if (rc) {
-		tcon->status = TID_NEED_TCON;
-	} else {
-		tcon->status = TID_GOOD;
-		tcon->need_reconnect = false;
-	}
-	spin_unlock(&tcon->tc_lock);
-}
-
-static void tree_connect_ipc(const unsigned int xid, char *tree,
-			     struct cifs_sb_info *cifs_sb,
-			     struct cifs_tcon *tcon)
-{
-	struct cifs_ses *ses = tcon->ses;
-
-	__tree_connect_ipc(xid, tree, cifs_sb, ses);
-	__tree_connect_ipc(xid, tree, cifs_sb, CIFS_DFS_ROOT_SES(ses));
-}
-
-static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
-				     struct cifs_sb_info *cifs_sb, char *tree, bool islink,
-				     struct dfs_cache_tgt_list *tl)
+static int tree_connect_dfs_target(const unsigned int xid,
+				   struct cifs_tcon *tcon,
+				   struct cifs_sb_info *cifs_sb,
+				   char *tree, bool islink,
+				   struct dfs_cache_tgt_list *tl)
 {
-	int rc;
+	const struct smb_version_operations *ops = tcon->ses->server->ops;
 	struct TCP_Server_Info *server = tcon->ses->server;
-	const struct smb_version_operations *ops = server->ops;
-	struct cifs_ses *root_ses = CIFS_DFS_ROOT_SES(tcon->ses);
-	char *share = NULL, *prefix = NULL;
 	struct dfs_cache_tgt_iterator *tit;
+	char *share = NULL, *prefix = NULL;
 	bool target_match;
-
-	tit = dfs_cache_get_tgt_iterator(tl);
-	if (!tit) {
-		rc = -ENOENT;
-		goto out;
-	}
+	int rc = -ENOENT;
 
 	/* Try to tree connect to all dfs targets */
-	for (; tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
-		const char *target = dfs_cache_get_tgt_name(tit);
-		DFS_CACHE_TGT_LIST(ntl);
-
+	for (tit = dfs_cache_get_tgt_iterator(tl);
+	     tit; tit = dfs_cache_get_next_tgt(tl, tit)) {
 		kfree(share);
 		kfree(prefix);
 		share = prefix = NULL;
@@ -482,74 +369,21 @@ static int __tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *t
 		}
 
 		dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, tit);
-		tree_connect_ipc(xid, tree, cifs_sb, tcon);
-
 		scnprintf(tree, MAX_TREE_SIZE, "\\%s", share);
-		if (!islink) {
-			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
-			break;
-		}
-
-		/*
-		 * If no dfs referrals were returned from link target, then just do a TREE_CONNECT
-		 * to it.  Otherwise, cache the dfs referral and then mark current tcp ses for
-		 * reconnect so either the demultiplex thread or the echo worker will reconnect to
-		 * newly resolved target.
-		 */
-		if (dfs_cache_find(xid, root_ses, cifs_sb->local_nls, cifs_remap(cifs_sb), target,
-				   NULL, &ntl)) {
-			rc = ops->tree_connect(xid, tcon->ses, tree, tcon, cifs_sb->local_nls);
-			if (rc)
-				continue;
-
+		rc = ops->tree_connect(xid, tcon->ses, tree,
+				       tcon, tcon->ses->local_nls);
+		if (islink && !rc && cifs_sb)
 			rc = cifs_update_super_prepath(cifs_sb, prefix);
-		} else {
-			/* Target is another dfs share */
-			rc = update_server_fullpath(server, cifs_sb, target);
-			dfs_cache_free_tgts(tl);
-
-			if (!rc) {
-				rc = -EREMOTE;
-				list_replace_init(&ntl.tl_list, &tl->tl_list);
-			} else
-				dfs_cache_free_tgts(&ntl);
-		}
 		break;
 	}
 
-out:
 	kfree(share);
 	kfree(prefix);
-
-	return rc;
-}
-
-static int tree_connect_dfs_target(const unsigned int xid, struct cifs_tcon *tcon,
-				   struct cifs_sb_info *cifs_sb, char *tree, bool islink,
-				   struct dfs_cache_tgt_list *tl)
-{
-	int rc;
-	int num_links = 0;
-	struct TCP_Server_Info *server = tcon->ses->server;
-	char *old_fullpath = server->leaf_fullpath;
-
-	do {
-		rc = __tree_connect_dfs_target(xid, tcon, cifs_sb, tree, islink, tl);
-		if (!rc || rc != -EREMOTE)
-			break;
-	} while (rc = -ELOOP, ++num_links < MAX_NESTED_LINKS);
-	/*
-	 * If we couldn't tree connect to any targets from last referral path, then
-	 * retry it from newly resolved dfs referral.
-	 */
-	if (rc && server->leaf_fullpath != old_fullpath)
-		cifs_signal_cifsd_for_reconnect(server, true);
-
 	dfs_cache_free_tgts(tl);
 	return rc;
 }
 
-int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const struct nls_table *nlsc)
+int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon)
 {
 	int rc;
 	struct TCP_Server_Info *server = tcon->ses->server;
@@ -591,7 +425,8 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 		cifs_server_lock(server);
 		scnprintf(tree, MAX_TREE_SIZE, "\\\\%s\\IPC$", server->hostname);
 		cifs_server_unlock(server);
-		rc = ops->tree_connect(xid, tcon->ses, tree, tcon, nlsc);
+		rc = ops->tree_connect(xid, tcon->ses, tree,
+				       tcon, tcon->ses->local_nls);
 		goto out;
 	}
 
@@ -599,14 +434,11 @@ int cifs_tree_connect(const unsigned int xid, struct cifs_tcon *tcon, const stru
 	if (!IS_ERR(sb))
 		cifs_sb = CIFS_SB(sb);
 
-	/*
-	 * Tree connect to last share in @tcon->tree_name whether dfs super or
-	 * cached dfs referral was not found.
-	 */
-	if (!cifs_sb || !server->leaf_fullpath ||
+	/* Tree connect to last share in @tcon->tree_name if no DFS referral */
+	if (!server->leaf_fullpath ||
 	    dfs_cache_noreq_find(server->leaf_fullpath + 1, &ref, &tl)) {
-		rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon,
-				       cifs_sb ? cifs_sb->local_nls : nlsc);
+		rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name,
+				       tcon, tcon->ses->local_nls);
 		goto out;
 	}