diff mbox series

[2/8] smb: client: allow creating special files via reparse points

Message ID 20231125220813.30538-3-pc@manguebit.com (mailing list archive)
State New, archived
Headers show
Series reparse points work | expand

Commit Message

Paulo Alcantara Nov. 25, 2023, 10:08 p.m. UTC
Add support for creating special files (e.g. char/block devices,
sockets, fifos) via NFS reparse points on SMB2+, which are fully
supported by most SMB servers and documented in MS-FSCC.

smb2_get_reparse_inode() creates the file with a corresponding reparse
point buffer set in @iov through a single roundtrip to the server.

Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
---
 fs/smb/client/cifsproto.h |  8 +++-
 fs/smb/client/dir.c       |  7 +--
 fs/smb/client/file.c      | 10 +++--
 fs/smb/client/inode.c     | 74 +++++++++++++++++++-----------
 fs/smb/client/link.c      | 10 +++--
 fs/smb/client/smb2glob.h  | 25 ++++++-----
 fs/smb/client/smb2inode.c | 75 +++++++++++++++++++++++++++++++
 fs/smb/client/smb2ops.c   | 94 +++++++++++++++++++++++++++++++++++----
 fs/smb/client/smb2proto.h |  7 +++
 fs/smb/client/trace.h     |  4 +-
 10 files changed, 255 insertions(+), 59 deletions(-)

Comments

kernel test robot Nov. 26, 2023, 12:14 a.m. UTC | #1
Hi Paulo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on cifs/for-next]
[also build test WARNING on next-20231124]
[cannot apply to linus/master v6.7-rc2]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Paulo-Alcantara/smb-client-extend-smb2_compound_op-to-accept-more-commands/20231126-061137
base:   git://git.samba.org/sfrench/cifs-2.6.git for-next
patch link:    https://lore.kernel.org/r/20231125220813.30538-3-pc%40manguebit.com
patch subject: [PATCH 2/8] smb: client: allow creating special files via reparse points
config: x86_64-rhel-8.3-rust (https://download.01.org/0day-ci/archive/20231126/202311260746.HOJ039BV-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231126/202311260746.HOJ039BV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311260746.HOJ039BV-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/smb/client/inode.c:1320:6: warning: variable 'rc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
           if (!data) {
               ^~~~~
   fs/smb/client/inode.c:1331:10: note: uninitialized use occurs here
           switch (rc) {
                   ^~
   fs/smb/client/inode.c:1320:2: note: remove the 'if' if its condition is always true
           if (!data) {
           ^~~~~~~~~~~
   fs/smb/client/inode.c:1310:8: note: initialize the variable 'rc' to silence this warning
           int rc;
                 ^
                  = 0
   1 warning generated.


vim +1320 fs/smb/client/inode.c

  1297	
  1298	static int smb311_posix_get_fattr(struct cifs_open_info_data *data,
  1299					  struct cifs_fattr *fattr,
  1300					  const char *full_path,
  1301					  struct super_block *sb,
  1302					  const unsigned int xid)
  1303	{
  1304		struct cifs_open_info_data tmp_data = {};
  1305		struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
  1306		struct cifs_tcon *tcon;
  1307		struct tcon_link *tlink;
  1308		struct cifs_sid owner, group;
  1309		int tmprc;
  1310		int rc;
  1311	
  1312		tlink = cifs_sb_tlink(cifs_sb);
  1313		if (IS_ERR(tlink))
  1314			return PTR_ERR(tlink);
  1315		tcon = tlink_tcon(tlink);
  1316	
  1317		/*
  1318		 * 1. Fetch file metadata if not provided (data)
  1319		 */
> 1320		if (!data) {
  1321			rc = smb311_posix_query_path_info(xid, tcon, cifs_sb,
  1322							  full_path, &tmp_data,
  1323							  &owner, &group);
  1324			data = &tmp_data;
  1325		}
  1326	
  1327		/*
  1328		 * 2. Convert it to internal cifs metadata (fattr)
  1329		 */
  1330	
  1331		switch (rc) {
  1332		case 0:
  1333			if (cifs_open_data_reparse(data)) {
  1334				rc = reparse_info_to_fattr(data, sb, xid, tcon,
  1335							   full_path, fattr,
  1336							   &owner, &group);
  1337			} else {
  1338				smb311_posix_info_to_fattr(fattr, data,
  1339							   &owner, &group, sb);
  1340			}
  1341			break;
  1342		case -EREMOTE:
  1343			/* DFS link, no metadata available on this server */
  1344			cifs_create_junction_fattr(fattr, sb);
  1345			rc = 0;
  1346			break;
  1347		case -EACCES:
  1348			/*
  1349			 * For SMB2 and later the backup intent flag
  1350			 * is already sent if needed on open and there
  1351			 * is no path based FindFirst operation to use
  1352			 * to retry with so nothing we can do, bail out
  1353			 */
  1354			goto out;
  1355		default:
  1356			cifs_dbg(FYI, "%s: unhandled err rc %d\n", __func__, rc);
  1357			goto out;
  1358		}
  1359	
  1360		/*
  1361		 * 3. Tweak fattr based on mount options
  1362		 */
  1363		/* check for Minshall+French symlinks */
  1364		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) {
  1365			tmprc = check_mf_symlink(xid, tcon, cifs_sb, fattr, full_path);
  1366			cifs_dbg(FYI, "check_mf_symlink: %d\n", tmprc);
  1367		}
  1368	
  1369	out:
  1370		cifs_put_tlink(tlink);
  1371		cifs_free_open_info(data);
  1372		return rc;
  1373	}
  1374
diff mbox series

Patch

diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index 46feaa0880bd..0adeaa84b662 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -211,8 +211,12 @@  int cifs_get_inode_info(struct inode **inode, const char *full_path,
 bool cifs_reparse_point_to_fattr(struct cifs_sb_info *cifs_sb,
 				 struct cifs_fattr *fattr,
 				 struct cifs_open_info_data *data);
-extern int smb311_posix_get_inode_info(struct inode **pinode, const char *search_path,
-			struct super_block *sb, unsigned int xid);
+
+extern int smb311_posix_get_inode_info(struct inode **inode,
+				       const char *full_path,
+				       struct cifs_open_info_data *data,
+				       struct super_block *sb,
+				       const unsigned int xid);
 extern int cifs_get_inode_info_unix(struct inode **pinode,
 			const unsigned char *search_path,
 			struct super_block *sb, unsigned int xid);
diff --git a/fs/smb/client/dir.c b/fs/smb/client/dir.c
index 580a27a3a7e6..89333d9bce36 100644
--- a/fs/smb/client/dir.c
+++ b/fs/smb/client/dir.c
@@ -680,9 +680,10 @@  cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry,
 		 full_path, d_inode(direntry));
 
 again:
-	if (pTcon->posix_extensions)
-		rc = smb311_posix_get_inode_info(&newInode, full_path, parent_dir_inode->i_sb, xid);
-	else if (pTcon->unix_ext) {
+	if (pTcon->posix_extensions) {
+		rc = smb311_posix_get_inode_info(&newInode, full_path, NULL,
+						 parent_dir_inode->i_sb, xid);
+	} else if (pTcon->unix_ext) {
 		rc = cifs_get_inode_info_unix(&newInode, full_path,
 					      parent_dir_inode->i_sb, xid);
 	} else {
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index cf17e3dd703e..2b69c4e79b17 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -1020,14 +1020,16 @@  cifs_reopen_file(struct cifsFileInfo *cfile, bool can_flush)
 		if (!is_interrupt_error(rc))
 			mapping_set_error(inode->i_mapping, rc);
 
-		if (tcon->posix_extensions)
-			rc = smb311_posix_get_inode_info(&inode, full_path, inode->i_sb, xid);
-		else if (tcon->unix_ext)
+		if (tcon->posix_extensions) {
+			rc = smb311_posix_get_inode_info(&inode, full_path,
+							 NULL, inode->i_sb, xid);
+		} else if (tcon->unix_ext) {
 			rc = cifs_get_inode_info_unix(&inode, full_path,
 						      inode->i_sb, xid);
-		else
+		} else {
 			rc = cifs_get_inode_info(&inode, full_path, NULL,
 						 inode->i_sb, xid, NULL);
+		}
 	}
 	/*
 	 * Else we are writing out data to server already and could deadlock if
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 47f49be69ced..7baa02940bce 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1059,7 +1059,9 @@  static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 				 const unsigned int xid,
 				 struct cifs_tcon *tcon,
 				 const char *full_path,
-				 struct cifs_fattr *fattr)
+				 struct cifs_fattr *fattr,
+				 struct cifs_sid *owner,
+				 struct cifs_sid *group)
 {
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
@@ -1090,7 +1092,8 @@  static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 		rc = 0;
 		goto out;
 	default:
-		if (data->symlink_target) {
+		/* Check for cached reparse point data */
+		if (data->symlink_target || data->reparse.buf) {
 			rc = 0;
 		} else if (server->ops->parse_reparse_point) {
 			rc = server->ops->parse_reparse_point(cifs_sb,
@@ -1099,7 +1102,10 @@  static int reparse_info_to_fattr(struct cifs_open_info_data *data,
 		break;
 	}
 
-	cifs_open_info_to_fattr(fattr, data, sb);
+	if (tcon->posix_extensions)
+		smb311_posix_info_to_fattr(fattr, data, owner, group, sb);
+	else
+		cifs_open_info_to_fattr(fattr, data, sb);
 out:
 	free_rsp_buf(rsp_buftype, rsp_iov.iov_base);
 	return rc;
@@ -1150,7 +1156,8 @@  static int cifs_get_fattr(struct cifs_open_info_data *data,
 		 */
 		if (cifs_open_data_reparse(data)) {
 			rc = reparse_info_to_fattr(data, sb, xid, tcon,
-						   full_path, fattr);
+						   full_path, fattr,
+						   NULL, NULL);
 		} else {
 			cifs_open_info_to_fattr(fattr, data, sb);
 		}
@@ -1288,12 +1295,13 @@  int cifs_get_inode_info(struct inode **inode,
 	return rc;
 }
 
-static int smb311_posix_get_fattr(struct cifs_fattr *fattr,
+static int smb311_posix_get_fattr(struct cifs_open_info_data *data,
+				  struct cifs_fattr *fattr,
 				  const char *full_path,
 				  struct super_block *sb,
 				  const unsigned int xid)
 {
-	struct cifs_open_info_data data = {};
+	struct cifs_open_info_data tmp_data = {};
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct cifs_tcon *tcon;
 	struct tcon_link *tlink;
@@ -1307,12 +1315,14 @@  static int smb311_posix_get_fattr(struct cifs_fattr *fattr,
 	tcon = tlink_tcon(tlink);
 
 	/*
-	 * 1. Fetch file metadata
+	 * 1. Fetch file metadata if not provided (data)
 	 */
-
-	rc = smb311_posix_query_path_info(xid, tcon, cifs_sb,
-					  full_path, &data,
-					  &owner, &group);
+	if (!data) {
+		rc = smb311_posix_query_path_info(xid, tcon, cifs_sb,
+						  full_path, &tmp_data,
+						  &owner, &group);
+		data = &tmp_data;
+	}
 
 	/*
 	 * 2. Convert it to internal cifs metadata (fattr)
@@ -1320,7 +1330,14 @@  static int smb311_posix_get_fattr(struct cifs_fattr *fattr,
 
 	switch (rc) {
 	case 0:
-		smb311_posix_info_to_fattr(fattr, &data, &owner, &group, sb);
+		if (cifs_open_data_reparse(data)) {
+			rc = reparse_info_to_fattr(data, sb, xid, tcon,
+						   full_path, fattr,
+						   &owner, &group);
+		} else {
+			smb311_posix_info_to_fattr(fattr, data,
+						   &owner, &group, sb);
+		}
 		break;
 	case -EREMOTE:
 		/* DFS link, no metadata available on this server */
@@ -1351,12 +1368,15 @@  static int smb311_posix_get_fattr(struct cifs_fattr *fattr,
 
 out:
 	cifs_put_tlink(tlink);
-	cifs_free_open_info(&data);
+	cifs_free_open_info(data);
 	return rc;
 }
 
-int smb311_posix_get_inode_info(struct inode **inode, const char *full_path,
-				struct super_block *sb, const unsigned int xid)
+int smb311_posix_get_inode_info(struct inode **inode,
+				const char *full_path,
+				struct cifs_open_info_data *data,
+				struct super_block *sb,
+				const unsigned int xid)
 {
 	struct cifs_fattr fattr = {};
 	int rc;
@@ -1366,7 +1386,7 @@  int smb311_posix_get_inode_info(struct inode **inode, const char *full_path,
 		return 0;
 	}
 
-	rc = smb311_posix_get_fattr(&fattr, full_path, sb, xid);
+	rc = smb311_posix_get_fattr(data, &fattr, full_path, sb, xid);
 	if (rc)
 		goto out;
 
@@ -1514,7 +1534,7 @@  struct inode *cifs_root_iget(struct super_block *sb)
 
 	convert_delimiter(path, CIFS_DIR_SEP(cifs_sb));
 	if (tcon->posix_extensions)
-		rc = smb311_posix_get_fattr(&fattr, path, sb, xid);
+		rc = smb311_posix_get_fattr(NULL, &fattr, path, sb, xid);
 	else
 		rc = cifs_get_fattr(NULL, sb, xid, NULL, &fattr, &inode, path);
 
@@ -1887,16 +1907,18 @@  cifs_mkdir_qinfo(struct inode *parent, struct dentry *dentry, umode_t mode,
 	int rc = 0;
 	struct inode *inode = NULL;
 
-	if (tcon->posix_extensions)
-		rc = smb311_posix_get_inode_info(&inode, full_path, parent->i_sb, xid);
+	if (tcon->posix_extensions) {
+		rc = smb311_posix_get_inode_info(&inode, full_path,
+						 NULL, parent->i_sb, xid);
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
-	else if (tcon->unix_ext)
+	} else if (tcon->unix_ext) {
 		rc = cifs_get_inode_info_unix(&inode, full_path, parent->i_sb,
 					      xid);
 #endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
-	else
+	} else {
 		rc = cifs_get_inode_info(&inode, full_path, NULL, parent->i_sb,
 					 xid, NULL);
+	}
 
 	if (rc)
 		return rc;
@@ -2577,13 +2599,15 @@  int cifs_revalidate_dentry_attr(struct dentry *dentry)
 		 dentry, cifs_get_time(dentry), jiffies);
 
 again:
-	if (cifs_sb_master_tcon(CIFS_SB(sb))->posix_extensions)
-		rc = smb311_posix_get_inode_info(&inode, full_path, sb, xid);
-	else if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
+	if (cifs_sb_master_tcon(CIFS_SB(sb))->posix_extensions) {
+		rc = smb311_posix_get_inode_info(&inode, full_path,
+						 NULL, sb, xid);
+	} else if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext) {
 		rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid);
-	else
+	} else {
 		rc = cifs_get_inode_info(&inode, full_path, NULL, sb,
 					 xid, NULL);
+	}
 	if (rc == -EAGAIN && count++ < 10)
 		goto again;
 out:
diff --git a/fs/smb/client/link.c b/fs/smb/client/link.c
index a1da50e66fbb..5ce0f74be4ec 100644
--- a/fs/smb/client/link.c
+++ b/fs/smb/client/link.c
@@ -614,14 +614,16 @@  cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
 					cifs_sb_target->local_nls); */
 
 	if (rc == 0) {
-		if (pTcon->posix_extensions)
-			rc = smb311_posix_get_inode_info(&newinode, full_path, inode->i_sb, xid);
-		else if (pTcon->unix_ext)
+		if (pTcon->posix_extensions) {
+			rc = smb311_posix_get_inode_info(&newinode, full_path,
+							 NULL, inode->i_sb, xid);
+		} else if (pTcon->unix_ext) {
 			rc = cifs_get_inode_info_unix(&newinode, full_path,
 						      inode->i_sb, xid);
-		else
+		} else {
 			rc = cifs_get_inode_info(&newinode, full_path, NULL,
 						 inode->i_sb, xid, NULL);
+		}
 
 		if (rc != 0) {
 			cifs_dbg(FYI, "Create symlink ok, getinodeinfo fail rc = %d\n",
diff --git a/fs/smb/client/smb2glob.h b/fs/smb/client/smb2glob.h
index 82e916ad167c..ca87a0011c33 100644
--- a/fs/smb/client/smb2glob.h
+++ b/fs/smb/client/smb2glob.h
@@ -23,17 +23,20 @@ 
  * Identifiers for functions that use the open, operation, close pattern
  * in smb2inode.c:smb2_compound_op()
  */
-#define SMB2_OP_SET_DELETE 1
-#define SMB2_OP_SET_INFO 2
-#define SMB2_OP_QUERY_INFO 3
-#define SMB2_OP_QUERY_DIR 4
-#define SMB2_OP_MKDIR 5
-#define SMB2_OP_RENAME 6
-#define SMB2_OP_DELETE 7
-#define SMB2_OP_HARDLINK 8
-#define SMB2_OP_SET_EOF 9
-#define SMB2_OP_RMDIR 10
-#define SMB2_OP_POSIX_QUERY_INFO 11
+enum smb2_compound_ops {
+	SMB2_OP_SET_DELETE = 1,
+	SMB2_OP_SET_INFO,
+	SMB2_OP_QUERY_INFO,
+	SMB2_OP_QUERY_DIR,
+	SMB2_OP_MKDIR,
+	SMB2_OP_RENAME,
+	SMB2_OP_DELETE,
+	SMB2_OP_HARDLINK,
+	SMB2_OP_SET_EOF,
+	SMB2_OP_RMDIR,
+	SMB2_OP_POSIX_QUERY_INFO,
+	SMB2_OP_SET_REPARSE
+};
 
 /* Used when constructing chained read requests. */
 #define CHAINED_REQUEST 1
diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c
index 98fa4f02fbd3..d662bad3b703 100644
--- a/fs/smb/client/smb2inode.c
+++ b/fs/smb/client/smb2inode.c
@@ -347,6 +347,22 @@  static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 			smb2_set_related(&rqst[num_rqst++]);
 			trace_smb3_hardlink_enter(xid, ses->Suid, tcon->tid, full_path);
 			break;
+		case SMB2_OP_SET_REPARSE:
+			rqst[num_rqst].rq_iov = vars->io_iov;
+			rqst[num_rqst].rq_nvec = ARRAY_SIZE(vars->io_iov);
+
+			rc = SMB2_ioctl_init(tcon, server, &rqst[num_rqst],
+					     COMPOUND_FID, COMPOUND_FID,
+					     FSCTL_SET_REPARSE_POINT,
+					     in_iov[i].iov_base,
+					     in_iov[i].iov_len, 0);
+			if (rc)
+				goto finished;
+			smb2_set_next_command(tcon, &rqst[num_rqst]);
+			smb2_set_related(&rqst[num_rqst++]);
+			trace_smb3_set_reparse_compound_enter(xid, ses->Suid,
+							      tcon->tid, full_path);
+			break;
 		default:
 			cifs_dbg(VFS, "Invalid command\n");
 			rc = -EINVAL;
@@ -503,6 +519,16 @@  static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 								  tcon->tid);
 			SMB2_set_info_free(&rqst[num_rqst++]);
 			break;
+		case SMB2_OP_SET_REPARSE:
+			if (rc) {
+				trace_smb3_set_reparse_compound_err(xid,  ses->Suid,
+								    tcon->tid, rc);
+			} else {
+				trace_smb3_set_reparse_compound_done(xid, ses->Suid,
+								     tcon->tid);
+			}
+			SMB2_ioctl_free(&rqst[num_rqst++]);
+			break;
 		}
 	}
 	SMB2_close_free(&rqst[num_rqst]);
@@ -887,3 +913,52 @@  smb2_set_file_info(struct inode *inode, const char *full_path,
 	cifs_put_tlink(tlink);
 	return rc;
 }
+
+struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
+				     struct super_block *sb,
+				     const unsigned int xid,
+				     struct cifs_tcon *tcon,
+				     const char *full_path,
+				     struct kvec *iov)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	struct cifsFileInfo *cfile;
+	struct inode *new = NULL;
+	struct kvec in_iov[2];
+	int cmds[2];
+	int da, co, cd;
+	int rc;
+
+	da = SYNCHRONIZE | DELETE |
+		FILE_READ_ATTRIBUTES |
+		FILE_WRITE_ATTRIBUTES;
+	co = CREATE_NOT_DIR | OPEN_REPARSE_POINT;
+	cd = FILE_CREATE;
+	cmds[0] = SMB2_OP_SET_REPARSE;
+	in_iov[0] = *iov;
+	in_iov[1].iov_base = data;
+	in_iov[1].iov_len = sizeof(*data);
+
+	if (tcon->posix_extensions) {
+		cmds[1] = SMB2_OP_POSIX_QUERY_INFO;
+		cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
+		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
+				      da, cd, co, ACL_NO_MODE, in_iov,
+				      cmds, 2, cfile, NULL, NULL, NULL, NULL);
+		if (!rc) {
+			rc = smb311_posix_get_inode_info(&new, full_path,
+							 data, sb, xid);
+		}
+	} else {
+		cmds[1] = SMB2_OP_QUERY_INFO;
+		cifs_get_writable_path(tcon, full_path, FIND_WR_ANY, &cfile);
+		rc = smb2_compound_op(xid, tcon, cifs_sb, full_path,
+				      da, cd, co, ACL_NO_MODE, in_iov,
+				      cmds, 2, cfile, NULL, NULL, NULL, NULL);
+		if (!rc) {
+			rc = cifs_get_inode_info(&new, full_path,
+						 data, sb, xid, NULL);
+		}
+	}
+	return rc ? ERR_PTR(rc) : new;
+}
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 82ab62fd0040..c1fe7ba02f6f 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -5133,11 +5133,88 @@  int cifs_sfu_make_node(unsigned int xid, struct inode *inode,
 	return rc;
 }
 
+static inline u64 mode_nfs_type(mode_t mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFBLK: return NFS_SPECFILE_BLK;
+	case S_IFCHR: return NFS_SPECFILE_CHR;
+	case S_IFIFO: return NFS_SPECFILE_FIFO;
+	case S_IFSOCK: return NFS_SPECFILE_SOCK;
+	}
+	return 0;
+}
+
+static int nfs_set_reparse_buf(struct reparse_posix_data *buf,
+			       mode_t mode, dev_t dev,
+			       struct kvec *iov)
+{
+	u64 type;
+	u16 len, dlen;
+
+	len = sizeof(*buf);
+
+	switch ((type = mode_nfs_type(mode))) {
+	case NFS_SPECFILE_BLK:
+	case NFS_SPECFILE_CHR:
+		dlen = sizeof(__le64);
+		break;
+	case NFS_SPECFILE_FIFO:
+	case NFS_SPECFILE_SOCK:
+		dlen = 0;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	buf->ReparseTag = cpu_to_le32(IO_REPARSE_TAG_NFS);
+	buf->Reserved = 0;
+	buf->InodeType = cpu_to_le64(type);
+	buf->ReparseDataLength = cpu_to_le16(len + dlen -
+					     sizeof(struct reparse_data_buffer));
+	*(__le64 *)buf->DataBuffer = cpu_to_le64(((u64)MAJOR(dev) << 32) |
+						 MINOR(dev));
+	iov->iov_base = buf;
+	iov->iov_len = len + dlen;
+	return 0;
+}
+
+static int nfs_make_node(unsigned int xid, struct inode *inode,
+			 struct dentry *dentry, struct cifs_tcon *tcon,
+			 const char *full_path, umode_t mode, dev_t dev)
+{
+	struct cifs_open_info_data data;
+	struct reparse_posix_data *p;
+	struct inode *new;
+	struct kvec iov;
+	__u8 buf[sizeof(*p) + sizeof(__le64)];
+	int rc;
+
+	p = (struct reparse_posix_data *)buf;
+	rc = nfs_set_reparse_buf(p, mode, dev, &iov);
+	if (rc)
+		return rc;
+
+	data = (struct cifs_open_info_data) {
+		.reparse_point = true,
+		.reparse = { .tag = IO_REPARSE_TAG_NFS, .posix = p, },
+	};
+
+	new = smb2_get_reparse_inode(&data, inode->i_sb, xid,
+				     tcon, full_path, &iov);
+	if (!IS_ERR(new))
+		d_instantiate(dentry, new);
+	else
+		rc = PTR_ERR(new);
+	cifs_free_open_info(&data);
+	return rc;
+}
+
 static int smb2_make_node(unsigned int xid, struct inode *inode,
 			  struct dentry *dentry, struct cifs_tcon *tcon,
 			  const char *full_path, umode_t mode, dev_t dev)
 {
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	int rc;
 
 	/*
 	 * Check if mounted with mount parm 'sfu' mount parm.
@@ -5145,15 +5222,14 @@  static int smb2_make_node(unsigned int xid, struct inode *inode,
 	 * supports block and char device (no socket & fifo),
 	 * and was used by default in earlier versions of Windows
 	 */
-	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL))
-		return -EPERM;
-	/*
-	 * TODO: Add ability to create instead via reparse point. Windows (e.g.
-	 * their current NFS server) uses this approach to expose special files
-	 * over SMB2/SMB3 and Samba will do this with SMB3.1.1 POSIX Extensions
-	 */
-	return cifs_sfu_make_node(xid, inode, dentry, tcon,
-				  full_path, mode, dev);
+	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
+		rc = cifs_sfu_make_node(xid, inode, dentry, tcon,
+					full_path, mode, dev);
+	} else {
+		rc = nfs_make_node(xid, inode, dentry, tcon,
+				   full_path, mode, dev);
+	}
+	return rc;
 }
 
 #ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
diff --git a/fs/smb/client/smb2proto.h b/fs/smb/client/smb2proto.h
index 46eff9ec302a..d4b2b339fdc3 100644
--- a/fs/smb/client/smb2proto.h
+++ b/fs/smb/client/smb2proto.h
@@ -56,6 +56,12 @@  extern int smb3_handle_read_data(struct TCP_Server_Info *server,
 extern int smb2_query_reparse_tag(const unsigned int xid, struct cifs_tcon *tcon,
 				struct cifs_sb_info *cifs_sb, const char *path,
 				__u32 *reparse_tag);
+struct inode *smb2_get_reparse_inode(struct cifs_open_info_data *data,
+				     struct super_block *sb,
+				     const unsigned int xid,
+				     struct cifs_tcon *tcon,
+				     const char *full_path,
+				     struct kvec *iov);
 int smb2_query_path_info(const unsigned int xid,
 			 struct cifs_tcon *tcon,
 			 struct cifs_sb_info *cifs_sb,
@@ -287,4 +293,5 @@  int smb311_posix_query_path_info(const unsigned int xid,
 int posix_info_parse(const void *beg, const void *end,
 		     struct smb2_posix_info_parsed *out);
 int posix_info_sid_size(const void *beg, const void *end);
+
 #endif			/* _SMB2PROTO_H */
diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h
index de199ec9f726..34f507584274 100644
--- a/fs/smb/client/trace.h
+++ b/fs/smb/client/trace.h
@@ -370,11 +370,11 @@  DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(rename_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(rmdir_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(set_eof_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(set_info_compound_enter);
+DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(set_reparse_compound_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(delete_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(mkdir_enter);
 DEFINE_SMB3_INF_COMPOUND_ENTER_EVENT(tdis_enter);
 
-
 DECLARE_EVENT_CLASS(smb3_inf_compound_done_class,
 	TP_PROTO(unsigned int xid,
 		__u32	tid,
@@ -408,6 +408,7 @@  DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(rename_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(rmdir_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(set_eof_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(set_info_compound_done);
+DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(set_reparse_compound_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(delete_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(mkdir_done);
 DEFINE_SMB3_INF_COMPOUND_DONE_EVENT(tdis_done);
@@ -451,6 +452,7 @@  DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(rename_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(rmdir_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(set_eof_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(set_info_compound_err);
+DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(set_reparse_compound_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(mkdir_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(delete_err);
 DEFINE_SMB3_INF_COMPOUND_ERR_EVENT(tdis_err);