Merge tag '6.2-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "cifs/smb3 client fixes, mostly related to reconnect and/or DFS:

   - two important reconnect fixes: cases where status of recently
     connected IPCs and shares were not being updated leaving them in an
     incorrect state

   - fix for older Windows servers that would return
     STATUS_OBJECT_NAME_INVALID to query info requests on DFS links in a
     namespace that contained non-ASCII characters, reducing number of
     wasted roundtrips.

   - fix for leaked -ENOMEM to userspace when cifs.ko couldn't perform
     I/O due to a disconnected server, expired or deleted session.

   - removal of all unneeded DFS related mount option string parsing
     (now using fs_context for automounts)

   - improve clarity/readability, moving various DFS related functions
     out of fs/cifs/connect.c (which was getting too big to be readable)
     to new file.

   - Fix problem when large number of DFS connections. Allow sharing of
     DFS connections and fix how the referral paths are matched

   - Referral caching fix: Instead of looking up ipc connections to
     refresh cached referrals, store direct dfs root server's IPC
     pointer in new sessions so it can simply be accessed to either
     refresh or create a new referral that such connections belong to.

   - Fix to allow dfs root server's connections to also failover

   - Optimized reconnect of nested DFS links

   - Set correct status of IPC connections marked for reconnect"

* tag '6.2-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module number
  cifs: don't leak -ENOMEM in smb2_open_file()
  cifs: use origin fullpath for automounts
  cifs: set correct status of tcon ipc when reconnecting
  cifs: optimize reconnect of nested links
  cifs: fix source pathname comparison of dfs supers
  cifs: fix confusing debug message
  cifs: don't block in dfs_cache_noreq_update_tgthint()
  cifs: refresh root referrals
  cifs: fix refresh of cached referrals
  cifs: don't refresh cached referrals from unactive mounts
  cifs: share dfs connections and supers
  cifs: split out ses and tcon retrieval from mount_get_conns()
  cifs: set resolved ip in sockaddr
  cifs: remove unused smb3_fs_context::mount_options
  cifs: get rid of mount options string parsing
  cifs: use fs_context for automounts
  cifs: reduce roundtrips on create/qinfo requests
  cifs: set correct ipc status after initial tree connect
  cifs: set correct tcon status after initial tree connect

fs/cifs/Makefile

@@ -21,7 +21,7 @@ cifs-$(CONFIG_CIFS_XATTR) += xattr.o
 
 cifs-$(CONFIG_CIFS_UPCALL) += cifs_spnego.o
 
-cifs-$(CONFIG_CIFS_DFS_UPCALL) += cifs_dfs_ref.o dfs_cache.o
+cifs-$(CONFIG_CIFS_DFS_UPCALL) += cifs_dfs_ref.o dfs_cache.o dfs.o
 
 cifs-$(CONFIG_CIFS_SWN_UPCALL) += netlink.o cifs_swn.o
 

fs/cifs/cifs_debug.c

@@ -372,6 +372,14 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 		seq_printf(m, "\nIn Send: %d In MaxReq Wait: %d",
 				atomic_read(&server->in_send),
 				atomic_read(&server->num_waiters));
+		if (IS_ENABLED(CONFIG_CIFS_DFS_UPCALL)) {
+			if (server->origin_fullpath)
+				seq_printf(m, "\nDFS origin full path: %s",
+					   server->origin_fullpath);
+			if (server->leaf_fullpath)
+				seq_printf(m, "\nDFS leaf full path:   %s",
+					   server->leaf_fullpath);
+		}
 
 		seq_printf(m, "\n\n\tSessions: ");
 		i = 0;

fs/cifs/cifs_dfs_ref.c

@@ -21,8 +21,7 @@
 #include "cifsfs.h"
 #include "dns_resolve.h"
 #include "cifs_debug.h"
-#include "cifs_unicode.h"
-#include "dfs_cache.h"
+#include "dfs.h"
 #include "fs_context.h"
 
 static LIST_HEAD(cifs_dfs_automount_list);
@@ -60,7 +59,7 @@ void cifs_dfs_release_automount_timer(void)
  * Returns pointer to the built string, or a ERR_PTR. Caller is responsible
  * for freeing the returned string.
  */
-static char *
+char *
 cifs_build_devname(char *nodename, const char *prepath)
 {
 	size_t pplen;
@@ -119,200 +118,34 @@ cifs_build_devname(char *nodename, const char *prepath)
 	return dev;
 }
 
-
-/**
- * cifs_compose_mount_options	-	creates mount options for referral
- * @sb_mountdata:	parent/root DFS mount options (template)
- * @fullpath:		full path in UNC format
- * @ref:		optional server's referral
- * @devname:		return the built cifs device name if passed pointer not NULL
- * creates mount options for submount based on template options sb_mountdata
- * and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
- *
- * Returns: pointer to new mount options or ERR_PTR.
- * Caller is responsible for freeing returned value if it is not error.
- */
-char *cifs_compose_mount_options(const char *sb_mountdata,
-				 const char *fullpath,
-				 const struct dfs_info3_param *ref,
-				 char **devname)
+static int set_dest_addr(struct smb3_fs_context *ctx, const char *full_path)
 {
+	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
 	int rc;
-	char *name;
-	char *mountdata = NULL;
-	const char *prepath = NULL;
-	int md_len;
-	char *tkn_e;
-	char *srvIP = NULL;
-	char sep = ',';
-	int off, noff;
-
-	if (sb_mountdata == NULL)
-		return ERR_PTR(-EINVAL);
-
-	if (ref) {
-		if (WARN_ON_ONCE(!ref->node_name || ref->path_consumed < 0))
-			return ERR_PTR(-EINVAL);
-
-		if (strlen(fullpath) - ref->path_consumed) {
-			prepath = fullpath + ref->path_consumed;
-			/* skip initial delimiter */
-			if (*prepath == '/' || *prepath == '\\')
-				prepath++;
-		}
-
-		name = cifs_build_devname(ref->node_name, prepath);
-		if (IS_ERR(name)) {
-			rc = PTR_ERR(name);
-			name = NULL;
-			goto compose_mount_options_err;
-		}
-	} else {
-		name = cifs_build_devname((char *)fullpath, NULL);
-		if (IS_ERR(name)) {
-			rc = PTR_ERR(name);
-			name = NULL;
-			goto compose_mount_options_err;
-		}
-	}
-
-	rc = dns_resolve_server_name_to_ip(name, &srvIP, NULL);
-	if (rc < 0) {
-		cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",
-			 __func__, name, rc);
-		goto compose_mount_options_err;
-	}
-
-	/*
-	 * In most cases, we'll be building a shorter string than the original,
-	 * but we do have to assume that the address in the ip= option may be
-	 * much longer than the original. Add the max length of an address
-	 * string to the length of the original string to allow for worst case.
-	 */
-	md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
-	mountdata = kzalloc(md_len + sizeof("ip=") + 1, GFP_KERNEL);
-	if (mountdata == NULL) {
-		rc = -ENOMEM;
-		goto compose_mount_options_err;
-	}
-
-	/* copy all options except of unc,ip,prefixpath */
-	off = 0;
-	if (strncmp(sb_mountdata, "sep=", 4) == 0) {
-			sep = sb_mountdata[4];
-			strncpy(mountdata, sb_mountdata, 5);
-			off += 5;
-	}
-
-	do {
-		tkn_e = strchr(sb_mountdata + off, sep);
-		if (tkn_e == NULL)
-			noff = strlen(sb_mountdata + off);
-		else
-			noff = tkn_e - (sb_mountdata + off) + 1;
-
-		if (strncasecmp(sb_mountdata + off, "cruid=", 6) == 0) {
-			off += noff;
-			continue;
-		}
-		if (strncasecmp(sb_mountdata + off, "unc=", 4) == 0) {
-			off += noff;
-			continue;
-		}
-		if (strncasecmp(sb_mountdata + off, "ip=", 3) == 0) {
-			off += noff;
-			continue;
-		}
-		if (strncasecmp(sb_mountdata + off, "prefixpath=", 11) == 0) {
-			off += noff;
-			continue;
-		}
-		strncat(mountdata, sb_mountdata + off, noff);
-		off += noff;
-	} while (tkn_e);
-	strcat(mountdata, sb_mountdata + off);
-	mountdata[md_len] = '\0';
-
-	/* copy new IP and ref share name */
-	if (mountdata[strlen(mountdata) - 1] != sep)
-		strncat(mountdata, &sep, 1);
-	strcat(mountdata, "ip=");
-	strcat(mountdata, srvIP);
-
-	if (devname)
-		*devname = name;
-	else
-		kfree(name);
-
-	/*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
-	/*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
 
-compose_mount_options_out:
-	kfree(srvIP);
-	return mountdata;
-
-compose_mount_options_err:
-	kfree(mountdata);
-	mountdata = ERR_PTR(rc);
-	kfree(name);
-	goto compose_mount_options_out;
-}
-
-/**
- * cifs_dfs_do_mount - mounts specified path using DFS full path
- *
- * Always pass down @fullpath to smb3_do_mount() so we can use the root server
- * to perform failover in case we failed to connect to the first target in the
- * referral.
- *
- * @mntpt:		directory entry for the path we are trying to automount
- * @cifs_sb:		parent/root superblock
- * @fullpath:		full path in UNC format
- */
-static struct vfsmount *cifs_dfs_do_mount(struct dentry *mntpt,
-					  struct cifs_sb_info *cifs_sb,
-					  const char *fullpath)
-{
-	struct vfsmount *mnt;
-	char *mountdata;
-	char *devname;
-
-	devname = kstrdup(fullpath, GFP_KERNEL);
-	if (!devname)
-		return ERR_PTR(-ENOMEM);
-
-	convert_delimiter(devname, '/');
-
-	/* TODO: change to call fs_context_for_mount(), fill in context directly, call fc_mount */
-
-	/* See afs_mntpt_do_automount in fs/afs/mntpt.c for an example */
-
-	/* strip first '\' from fullpath */
-	mountdata = cifs_compose_mount_options(cifs_sb->ctx->mount_options,
-					       fullpath + 1, NULL, NULL);
-	if (IS_ERR(mountdata)) {
-		kfree(devname);
-		return (struct vfsmount *)mountdata;
-	}
-
-	mnt = vfs_submount(mntpt, &cifs_fs_type, devname, mountdata);
-	kfree(mountdata);
-	kfree(devname);
-	return mnt;
+	rc = dns_resolve_server_name_to_ip(full_path, addr, NULL);
+	if (!rc)
+		cifs_set_port(addr, ctx->port);
+	return rc;
 }
 
 /*
  * Create a vfsmount that we can automount
  */
-static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
+static struct vfsmount *cifs_dfs_do_automount(struct path *path)
 {
+	int rc;
+	struct dentry *mntpt = path->dentry;
+	struct fs_context *fc;
 	struct cifs_sb_info *cifs_sb;
-	void *page;
+	void *page = NULL;
+	struct smb3_fs_context *ctx, *cur_ctx;
+	struct smb3_fs_context tmp;
 	char *full_path;
 	struct vfsmount *mnt;
 
-	cifs_dbg(FYI, "in %s\n", __func__);
-	BUG_ON(IS_ROOT(mntpt));
+	if (IS_ROOT(mntpt))
+		return ERR_PTR(-ESTALE);
 
 	/*
 	 * The MSDFS spec states that paths in DFS referral requests and
@@ -321,29 +154,53 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
 	 * gives us the latter, so we must adjust the result.
 	 */
 	cifs_sb = CIFS_SB(mntpt->d_sb);
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) {
-		mnt = ERR_PTR(-EREMOTE);
-		goto cdda_exit;
-	}
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS)
+		return ERR_PTR(-EREMOTE);
+
+	cur_ctx = cifs_sb->ctx;
+
+	fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, mntpt);
+	if (IS_ERR(fc))
+		return ERR_CAST(fc);
+
+	ctx = smb3_fc2context(fc);
 
 	page = alloc_dentry_path();
-	/* always use tree name prefix */
-	full_path = build_path_from_dentry_optional_prefix(mntpt, page, true);
+	full_path = dfs_get_automount_devname(mntpt, page);
 	if (IS_ERR(full_path)) {
 		mnt = ERR_CAST(full_path);
-		goto free_full_path;
+		goto out;
 	}
 
-	convert_delimiter(full_path, '\\');
+	convert_delimiter(full_path, '/');
 	cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
 
-	mnt = cifs_dfs_do_mount(mntpt, cifs_sb, full_path);
-	cifs_dbg(FYI, "%s: cifs_dfs_do_mount:%s , mnt:%p\n", __func__, full_path + 1, mnt);
+	tmp = *cur_ctx;
+	tmp.source = full_path;
+	tmp.leaf_fullpath = NULL;
+	tmp.UNC = tmp.prepath = NULL;
+
+	rc = smb3_fs_context_dup(ctx, &tmp);
+	if (rc) {
+		mnt = ERR_PTR(rc);
+		goto out;
+	}
+
+	rc = set_dest_addr(ctx, full_path);
+	if (rc) {
+		mnt = ERR_PTR(rc);
+		goto out;
+	}
+
+	rc = smb3_parse_devname(full_path, ctx);
+	if (!rc)
+		mnt = fc_mount(fc);
+	else
+		mnt = ERR_PTR(rc);
 
-free_full_path:
+out:
+	put_fs_context(fc);
 	free_dentry_path(page);
-cdda_exit:
-	cifs_dbg(FYI, "leaving %s\n" , __func__);
 	return mnt;
 }
 
@@ -354,9 +211,9 @@ struct vfsmount *cifs_dfs_d_automount(struct path *path)
 {
 	struct vfsmount *newmnt;
 
-	cifs_dbg(FYI, "in %s\n", __func__);
+	cifs_dbg(FYI, "%s: %pd\n", __func__, path->dentry);
 
-	newmnt = cifs_dfs_do_automount(path->dentry);
+	newmnt = cifs_dfs_do_automount(path);
 	if (IS_ERR(newmnt)) {
 		cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__);
 		return newmnt;

fs/cifs/cifsfs.c

@@ -896,12 +896,6 @@ cifs_smb3_do_mount(struct file_system_type *fs_type,
 		goto out;
 	}
 
-	rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);
-	if (rc) {
-		root = ERR_PTR(rc);
-		goto out;
-	}
-
 	rc = cifs_setup_cifs_sb(cifs_sb);
 	if (rc) {
 		root = ERR_PTR(rc);

fs/cifs/cifsfs.h

@@ -153,6 +153,6 @@ extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */
 
 /* when changing internal version - update following two lines at same time */
-#define SMB3_PRODUCT_BUILD 40
-#define CIFS_VERSION   "2.40"
+#define SMB3_PRODUCT_BUILD 41
+#define CIFS_VERSION   "2.41"
 #endif				/* _CIFSFS_H */

fs/cifs/cifsglob.h

@@ -107,6 +107,8 @@
 
 #define CIFS_MAX_WORKSTATION_LEN  (__NEW_UTS_LEN + 1)  /* reasonable max for client */
 
+#define CIFS_DFS_ROOT_SES(ses) ((ses)->dfs_root_ses ?: (ses))
+
 /*
  * CIFS vfs client Status information (based on what we know.)
  */
@@ -738,8 +740,6 @@ struct TCP_Server_Info {
 	bool use_swn_dstaddr;
 	struct sockaddr_storage swn_dstaddr;
 #endif
-#ifdef CONFIG_CIFS_DFS_UPCALL
-	bool is_dfs_conn; /* if a dfs connection */
 	struct mutex refpath_lock; /* protects leaf_fullpath */
 	/*
 	 * Canonical DFS full paths that were used to chase referrals in mount and reconnect.
@@ -753,7 +753,6 @@ struct TCP_Server_Info {
 	 * format: \\HOST\SHARE\[OPTIONAL PATH]
 	 */
 	char *origin_fullpath, *leaf_fullpath, *current_fullpath;
-#endif
 };
 
 static inline bool is_smb1(struct TCP_Server_Info *server)
@@ -1102,6 +1101,7 @@ struct cifs_ses {
 	 */
 	unsigned long chans_need_reconnect;
 	/* ========= end: protected by chan_lock ======== */
+	struct cifs_ses *dfs_root_ses;
 };
 
 static inline bool
@@ -1760,6 +1760,18 @@ struct file_list {
 	struct cifsFileInfo *cfile;
 };
 
+struct cifs_mount_ctx {
+	struct cifs_sb_info *cifs_sb;
+	struct smb3_fs_context *fs_ctx;
+	unsigned int xid;
+	struct TCP_Server_Info *server;
+	struct cifs_ses *ses;
+	struct cifs_tcon *tcon;
+	struct cifs_ses *root_ses;
+	uuid_t mount_id;
+	char *origin_fullpath, *leaf_fullpath;
+};
+
 static inline void free_dfs_info_param(struct dfs_info3_param *param)
 {
 	if (param) {

fs/cifs/cifsproto.h

@@ -57,6 +57,9 @@ extern void exit_cifs_idmap(void);
 extern int init_cifs_spnego(void);
 extern void exit_cifs_spnego(void);
 extern const char *build_path_from_dentry(struct dentry *, void *);
+char *__build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
+					       const char *tree, int tree_len,
+					       bool prefix);
 extern char *build_path_from_dentry_optional_prefix(struct dentry *direntry,
 						    void *page, bool prefix);
 static inline void *alloc_dentry_path(void)
@@ -75,9 +78,7 @@ extern char *cifs_build_path_to_root(struct smb3_fs_context *ctx,
 				     struct cifs_tcon *tcon,
 				     int add_treename);
 extern char *build_wildcard_path_from_dentry(struct dentry *direntry);
-extern char *cifs_compose_mount_options(const char *sb_mountdata,
-		const char *fullpath, const struct dfs_info3_param *ref,
-		char **devname);
+char *cifs_build_devname(char *nodename, const char *prepath);
 extern void delete_mid(struct mid_q_entry *mid);
 extern void release_mid(struct mid_q_entry *mid);
 extern void cifs_wake_up_task(struct mid_q_entry *mid);
@@ -244,6 +245,10 @@ extern int cifs_read_page_from_socket(struct TCP_Server_Info *server,
 					unsigned int page_offset,
 					unsigned int to_read);
 extern int cifs_setup_cifs_sb(struct cifs_sb_info *cifs_sb);
+void cifs_mount_put_conns(struct cifs_mount_ctx *mnt_ctx);
+int cifs_mount_get_session(struct cifs_mount_ctx *mnt_ctx);
+int cifs_is_path_remote(struct cifs_mount_ctx *mnt_ctx);
+int cifs_mount_get_tcon(struct cifs_mount_ctx *mnt_ctx);
 extern int cifs_match_super(struct super_block *, void *);
 extern int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx);
 extern void cifs_umount(struct cifs_sb_info *);
@@ -561,9 +566,6 @@ extern int check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 extern int E_md4hash(const unsigned char *passwd, unsigned char *p16,
 			const struct nls_table *codepage);
 
-extern int
-cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname);
-
 extern struct TCP_Server_Info *
 cifs_find_tcp_session(struct smb3_fs_context *ctx);
 

fs/cifs/dfs.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022 Paulo Alcantara <palcantara@suse.de>
+ */
+
+#ifndef _CIFS_DFS_H
+#define _CIFS_DFS_H
+
+#include "cifsglob.h"
+#include "fs_context.h"
+#include "cifs_unicode.h"
+
+int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,
+			      struct smb3_fs_context *ctx);
+int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx, bool *isdfs);
+
+static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path)
+{
+	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));
+}
+
+static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *path,
+				   struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tl)
+{
+	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;
+
+	return dfs_cache_find(mnt_ctx->xid, mnt_ctx->root_ses, cifs_sb->local_nls,
+			      cifs_remap(cifs_sb), path, ref, tl);
+}
+
+static inline char *dfs_get_automount_devname(struct dentry *dentry, void *page)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+	struct TCP_Server_Info *server = tcon->ses->server;
+
+	if (unlikely(!server->origin_fullpath))
+		return ERR_PTR(-EREMOTE);
+
+	return __build_path_from_dentry_optional_prefix(dentry, page,
+							server->origin_fullpath,
+							strlen(server->origin_fullpath),
+							true);
+}
+
+#endif /* _CIFS_DFS_H */

fs/cifs/dfs_cache.h

@@ -38,7 +38,7 @@ int dfs_cache_noreq_find(const char *path, struct dfs_info3_param *ref,
 int dfs_cache_update_tgthint(const unsigned int xid, struct cifs_ses *ses,
 			     const struct nls_table *cp, int remap, const char *path,
 			     const struct dfs_cache_tgt_iterator *it);
-int dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it);
+void dfs_cache_noreq_update_tgthint(const char *path, const struct dfs_cache_tgt_iterator *it);
 int dfs_cache_get_tgt_referral(const char *path, const struct dfs_cache_tgt_iterator *it,
 			       struct dfs_info3_param *ref);
 int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,

fs/cifs/dir.c

@@ -78,14 +78,13 @@ build_path_from_dentry(struct dentry *direntry, void *page)
 						      prefix);
 }
 
-char *
-build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
+char *__build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
+					       const char *tree, int tree_len,
 					       bool prefix)
 {
 	int dfsplen;
 	int pplen = 0;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
-	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
 	char dirsep = CIFS_DIR_SEP(cifs_sb);
 	char *s;
 
@@ -93,7 +92,7 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
 		return ERR_PTR(-ENOMEM);
 
 	if (prefix)
-		dfsplen = strnlen(tcon->tree_name, MAX_TREE_SIZE + 1);
+		dfsplen = strnlen(tree, tree_len + 1);
 	else
 		dfsplen = 0;
 
@@ -123,7 +122,7 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
 	}
 	if (dfsplen) {
 		s -= dfsplen;
-		memcpy(s, tcon->tree_name, dfsplen);
+		memcpy(s, tree, dfsplen);
 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS) {
 			int i;
 			for (i = 0; i < dfsplen; i++) {
@@ -135,6 +134,16 @@ build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
 	return s;
 }
 
+char *build_path_from_dentry_optional_prefix(struct dentry *direntry, void *page,
+					     bool prefix)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+
+	return __build_path_from_dentry_optional_prefix(direntry, page, tcon->tree_name,
+							MAX_TREE_SIZE, prefix);
+}
+
 /*
  * Don't allow path components longer than the server max.
  * Don't allow the separator character in a path component.

fs/cifs/dns_resolve.c

@@ -12,6 +12,7 @@
  *
  */
 
+#include <linux/inet.h>
 #include <linux/slab.h>
 #include <linux/dns_resolver.h>
 #include "dns_resolve.h"
@@ -25,17 +26,13 @@
  * @ip_addr: Where to return the IP address.
  * @expiry: Where to return the expiry time for the dns record.
  *
- * The IP address will be returned in string form, and the caller is
- * responsible for freeing it.
- *
- * Returns length of result on success, -ve on error.
+ * Returns zero success, -ve on error.
  */
 int
-dns_resolve_server_name_to_ip(const char *unc, char **ip_addr, time64_t *expiry)
+dns_resolve_server_name_to_ip(const char *unc, struct sockaddr *ip_addr, time64_t *expiry)
 {
-	struct sockaddr_storage ss;
 	const char *hostname, *sep;
-	char *name;
+	char *ip;
 	int len, rc;
 
 	if (!ip_addr || !unc)
@@ -60,30 +57,32 @@ dns_resolve_server_name_to_ip(const char *unc, char **ip_addr, time64_t *expiry)
 			 __func__, unc);
 
 	/* Try to interpret hostname as an IPv4 or IPv6 address */
-	rc = cifs_convert_address((struct sockaddr *)&ss, hostname, len);
-	if (rc > 0)
-		goto name_is_IP_address;
+	rc = cifs_convert_address(ip_addr, hostname, len);
+	if (rc > 0) {
+		cifs_dbg(FYI, "%s: unc is IP, skipping dns upcall: %*.*s\n", __func__, len, len,
+			 hostname);
+		return 0;
+	}
 
 	/* Perform the upcall */
 	rc = dns_query(current->nsproxy->net_ns, NULL, hostname, len,
-		       NULL, ip_addr, expiry, false);
-	if (rc < 0)
+		       NULL, &ip, expiry, false);
+	if (rc < 0) {
 		cifs_dbg(FYI, "%s: unable to resolve: %*.*s\n",
 			 __func__, len, len, hostname);
-	else
+	} else {
 		cifs_dbg(FYI, "%s: resolved: %*.*s to %s expiry %llu\n",
-			 __func__, len, len, hostname, *ip_addr,
+			 __func__, len, len, hostname, ip,
 			 expiry ? (*expiry) : 0);
-	return rc;
 
-name_is_IP_address:
-	name = kmalloc(len + 1, GFP_KERNEL);
-	if (!name)
-		return -ENOMEM;
-	memcpy(name, hostname, len);
-	name[len] = 0;
-	cifs_dbg(FYI, "%s: unc is IP, skipping dns upcall: %s\n",
-		 __func__, name);
-	*ip_addr = name;
-	return 0;
+		rc = cifs_convert_address(ip_addr, ip, strlen(ip));
+		kfree(ip);
+
+		if (!rc) {
+			cifs_dbg(FYI, "%s: unable to determine ip address\n", __func__);
+			rc = -EHOSTUNREACH;
+		} else
+			rc = 0;
+	}
+	return rc;
 }

fs/cifs/dns_resolve.h

@@ -11,8 +11,10 @@
 #ifndef _DNS_RESOLVE_H
 #define _DNS_RESOLVE_H
 
+#include <linux/net.h>
+
 #ifdef __KERNEL__
-extern int dns_resolve_server_name_to_ip(const char *unc, char **ip_addr, time64_t *expiry);
+int dns_resolve_server_name_to_ip(const char *unc, struct sockaddr *ip_addr, time64_t *expiry);
 #endif /* KERNEL */
 
 #endif /* _DNS_RESOLVE_H */

fs/cifs/fs_context.c

@@ -308,7 +308,6 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 {
 	memcpy(new_ctx, ctx, sizeof(*ctx));
 	new_ctx->prepath = NULL;
-	new_ctx->mount_options = NULL;
 	new_ctx->nodename = NULL;
 	new_ctx->username = NULL;
 	new_ctx->password = NULL;
@@ -317,11 +316,11 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	new_ctx->UNC = NULL;
 	new_ctx->source = NULL;
 	new_ctx->iocharset = NULL;
+	new_ctx->leaf_fullpath = NULL;
 	/*
 	 * Make sure to stay in sync with smb3_cleanup_fs_context_contents()
 	 */
 	DUP_CTX_STR(prepath);
-	DUP_CTX_STR(mount_options);
 	DUP_CTX_STR(username);
 	DUP_CTX_STR(password);
 	DUP_CTX_STR(server_hostname);
@@ -330,6 +329,7 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
 	DUP_CTX_STR(domainname);
 	DUP_CTX_STR(nodename);
 	DUP_CTX_STR(iocharset);
+	DUP_CTX_STR(leaf_fullpath);
 
 	return 0;
 }
@@ -569,17 +569,12 @@ static const struct fs_context_operations smb3_fs_context_ops = {
 static int smb3_fs_context_parse_monolithic(struct fs_context *fc,
 					   void *data)
 {
-	struct smb3_fs_context *ctx = smb3_fc2context(fc);
 	char *options = data, *key;
 	int ret = 0;
 
 	if (!options)
 		return 0;
 
-	ctx->mount_options = kstrdup(data, GFP_KERNEL);
-	if (ctx->mount_options == NULL)
-		return -ENOMEM;
-
 	ret = security_sb_eat_lsm_opts(options, &fc->security);
 	if (ret)
 		return ret;
@@ -1581,8 +1576,6 @@ smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
 	/*
 	 * Make sure this stays in sync with smb3_fs_context_dup()
 	 */
-	kfree(ctx->mount_options);
-	ctx->mount_options = NULL;
 	kfree(ctx->username);
 	ctx->username = NULL;
 	kfree_sensitive(ctx->password);
@@ -1601,6 +1594,8 @@ smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
 	ctx->iocharset = NULL;
 	kfree(ctx->prepath);
 	ctx->prepath = NULL;
+	kfree(ctx->leaf_fullpath);
+	ctx->leaf_fullpath = NULL;
 }
 
 void

fs/cifs/fs_context.h

@@ -264,8 +264,7 @@ struct smb3_fs_context {
 	__u16 compression; /* compression algorithm 0xFFFF default 0=disabled */
 	bool rootfs:1; /* if it's a SMB root file system */
 	bool witness:1; /* use witness protocol */
-
-	char *mount_options;
+	char *leaf_fullpath;
 };
 
 extern const struct fs_parameter_spec smb3_fs_parameters[];

fs/cifs/inode.c

@@ -993,12 +993,6 @@ int cifs_get_inode_info(struct inode **inode, const char *full_path,
 		}
 		rc = server->ops->query_path_info(xid, tcon, cifs_sb, full_path, &tmp_data,
 						  &adjust_tz, &is_reparse_point);
-#ifdef CONFIG_CIFS_DFS_UPCALL
-		if (rc == -ENOENT && is_tcon_dfs(tcon))
-			rc = cifs_dfs_query_info_nonascii_quirk(xid, tcon,
-								cifs_sb,
-								full_path);
-#endif
 		data = &tmp_data;
 	}
 

fs/cifs/misc.c

@@ -1258,44 +1258,28 @@ int match_target_ip(struct TCP_Server_Info *server,
 		    bool *result)
 {
 	int rc;
-	char *target, *tip = NULL;
-	struct sockaddr tipaddr;
+	char *target;
+	struct sockaddr_storage ss;
 
 	*result = false;
 
 	target = kzalloc(share_len + 3, GFP_KERNEL);
-	if (!target) {
-		rc = -ENOMEM;
-		goto out;
-	}
+	if (!target)
+		return -ENOMEM;
 
 	scnprintf(target, share_len + 3, "\\\\%.*s", (int)share_len, share);
 
 	cifs_dbg(FYI, "%s: target name: %s\n", __func__, target + 2);
 
-	rc = dns_resolve_server_name_to_ip(target, &tip, NULL);
-	if (rc < 0)
-		goto out;
-
-	cifs_dbg(FYI, "%s: target ip: %s\n", __func__, tip);
-
-	if (!cifs_convert_address(&tipaddr, tip, strlen(tip))) {
-		cifs_dbg(VFS, "%s: failed to convert target ip address\n",
-			 __func__);
-		rc = -EINVAL;
-		goto out;
-	}
-
-	*result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr,
-				    &tipaddr);
-	cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
-	rc = 0;
-
-out:
+	rc = dns_resolve_server_name_to_ip(target, (struct sockaddr *)&ss, NULL);
 	kfree(target);
-	kfree(tip);
 
+	if (rc < 0)
 		return rc;
+
+	*result = cifs_match_ipaddr((struct sockaddr *)&server->dstaddr, (struct sockaddr *)&ss);
+	cifs_dbg(FYI, "%s: ip addresses match: %u\n", __func__, *result);
+	return 0;
 }
 
 int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
@@ -1314,49 +1298,4 @@ int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
 	cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_USE_PREFIX_PATH;
 	return 0;
 }
-
-/** cifs_dfs_query_info_nonascii_quirk
- * Handle weird Windows SMB server behaviour. It responds with
- * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
- * for "\<server>\<dfsname>\<linkpath>" DFS reference,
- * where <dfsname> contains non-ASCII unicode symbols.
- *
- * Check such DFS reference.
- */
-int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid,
-				       struct cifs_tcon *tcon,
-				       struct cifs_sb_info *cifs_sb,
-				       const char *linkpath)
-{
-	char *treename, *dfspath, sep;
-	int treenamelen, linkpathlen, rc;
-
-	treename = tcon->tree_name;
-	/* MS-DFSC: All paths in REQ_GET_DFS_REFERRAL and RESP_GET_DFS_REFERRAL
-	 * messages MUST be encoded with exactly one leading backslash, not two
-	 * leading backslashes.
-	 */
-	sep = CIFS_DIR_SEP(cifs_sb);
-	if (treename[0] == sep && treename[1] == sep)
-		treename++;
-	linkpathlen = strlen(linkpath);
-	treenamelen = strnlen(treename, MAX_TREE_SIZE + 1);
-	dfspath = kzalloc(treenamelen + linkpathlen + 1, GFP_KERNEL);
-	if (!dfspath)
-		return -ENOMEM;
-	if (treenamelen)
-		memcpy(dfspath, treename, treenamelen);
-	memcpy(dfspath + treenamelen, linkpath, linkpathlen);
-	rc = dfs_cache_find(xid, tcon->ses, cifs_sb->local_nls,
-			    cifs_remap(cifs_sb), dfspath, NULL, NULL);
-	if (rc == 0) {
-		cifs_dbg(FYI, "DFS ref '%s' is found, emulate -EREMOTE\n",
-			 dfspath);
-		rc = -EREMOTE;
-	} else {
-		cifs_dbg(FYI, "%s: dfs_cache_find returned %d\n", __func__, rc);
-	}
-	kfree(dfspath);
-	return rc;
-}
 #endif

fs/cifs/smb2file.c

@@ -122,8 +122,8 @@ int smb2_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32
 		struct smb2_hdr *hdr = err_iov.iov_base;
 
 		if (unlikely(!err_iov.iov_base || err_buftype == CIFS_NO_BUFFER))
-			rc = -ENOMEM;
-		else if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
+			goto out;
+		if (hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
 			rc = smb2_parse_symlink_response(oparms->cifs_sb, &err_iov,
 							 &data->symlink_target);
 			if (!rc) {

fs/cifs/smb2inode.c

@@ -556,22 +556,42 @@ int smb2_query_path_info(const unsigned int xid, struct cifs_tcon *tcon,
 	rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, FILE_READ_ATTRIBUTES, FILE_OPEN,
 			      create_options, ACL_NO_MODE, data, SMB2_OP_QUERY_INFO, cfile,
 			      NULL, NULL, err_iov, err_buftype);
-	if (rc == -EOPNOTSUPP) {
-		if (err_iov[0].iov_base && err_buftype[0] != CIFS_NO_BUFFER &&
-		    ((struct smb2_hdr *)err_iov[0].iov_base)->Command == SMB2_CREATE &&
-		    ((struct smb2_hdr *)err_iov[0].iov_base)->Status == STATUS_STOPPED_ON_SYMLINK) {
-			rc = smb2_parse_symlink_response(cifs_sb, err_iov, &data->symlink_target);
+	if (rc) {
+		struct smb2_hdr *hdr = err_iov[0].iov_base;
+
+		if (unlikely(!hdr || err_buftype[0] == CIFS_NO_BUFFER))
+			goto out;
+		if (rc == -EOPNOTSUPP && hdr->Command == SMB2_CREATE &&
+		    hdr->Status == STATUS_STOPPED_ON_SYMLINK) {
+			rc = smb2_parse_symlink_response(cifs_sb, err_iov,
+							 &data->symlink_target);
 			if (rc)
 				goto out;
-		}
+
 			*reparse = true;
 			create_options |= OPEN_REPARSE_POINT;
 
 			/* Failed on a symbolic link - query a reparse point info */
 			cifs_get_readable_path(tcon, full_path, &cfile);
-		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path, FILE_READ_ATTRIBUTES,
-				      FILE_OPEN, create_options, ACL_NO_MODE, data,
-				      SMB2_OP_QUERY_INFO, cfile, NULL, NULL, NULL, NULL);
+			rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
+					      FILE_READ_ATTRIBUTES, FILE_OPEN,
+					      create_options, ACL_NO_MODE, data,
+					      SMB2_OP_QUERY_INFO, cfile, NULL, NULL,
+					      NULL, NULL);
+			goto out;
+		} else if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) &&
+			   hdr->Status == STATUS_OBJECT_NAME_INVALID) {
+			/*
+			 * Handle weird Windows SMB server behaviour. It responds with
+			 * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
+			 * for "\<server>\<dfsname>\<linkpath>" DFS reference,
+			 * where <dfsname> contains non-ASCII unicode symbols.
+			 */
+			rc = -EREMOTE;
+		}
+		if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb &&
+		    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS))
+			rc = -EOPNOTSUPP;
 	}
 
 out:

fs/cifs/smb2ops.c

@@ -796,7 +796,9 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc;
 	__le16 *utf16_path;
 	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+	int err_buftype = CIFS_NO_BUFFER;
 	struct cifs_open_parms oparms;
+	struct kvec err_iov = {};
 	struct cifs_fid fid;
 	struct cached_fid *cfid;
 
@@ -820,14 +822,32 @@ smb2_is_path_accessible(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL, NULL,
-		       NULL);
+	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
+		       &err_iov, &err_buftype);
 	if (rc) {
-		kfree(utf16_path);
-		return rc;
+		struct smb2_hdr *hdr = err_iov.iov_base;
+
+		if (unlikely(!hdr || err_buftype == CIFS_NO_BUFFER))
+			goto out;
+		/*
+		 * Handle weird Windows SMB server behaviour. It responds with
+		 * STATUS_OBJECT_NAME_INVALID code to SMB2 QUERY_INFO request
+		 * for "\<server>\<dfsname>\<linkpath>" DFS reference,
+		 * where <dfsname> contains non-ASCII unicode symbols.
+		 */
+		if (rc != -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) &&
+		    hdr->Status == STATUS_OBJECT_NAME_INVALID)
+			rc = -EREMOTE;
+		if (rc == -EREMOTE && IS_ENABLED(CONFIG_CIFS_DFS_UPCALL) && cifs_sb &&
+		    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS))
+			rc = -EOPNOTSUPP;
+		goto out;
 	}
 
 	rc = SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+
+out:
+	free_rsp_buf(err_buftype, err_iov.iov_base);
 	kfree(utf16_path);
 	return rc;
 }