Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 642 insertions, 0 deletions

diff --git a/fs/smb/client/link.c b/fs/smb/client/link.c
new file mode 100644
index 000000000..8d5d6aca7
--- /dev/null
+++ b/fs/smb/client/link.c
@@ -0,0 +1,642 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002,2008
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *
+ */
+#include <crypto/md5.h>
+#include <linux/fs.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/namei.h>
+#include "cifsfs.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "cifs_debug.h"
+#include "cifs_fs_sb.h"
+#include "cifs_unicode.h"
+#include "smb2proto.h"
+#include "cifs_ioctl.h"
+#include "fs_context.h"
+#include "reparse.h"
+
+/*
+ * M-F Symlink Functions - Begin
+ */
+
+#define CIFS_MF_SYMLINK_LEN_OFFSET (4+1)
+#define CIFS_MF_SYMLINK_MD5_OFFSET (CIFS_MF_SYMLINK_LEN_OFFSET+(4+1))
+#define CIFS_MF_SYMLINK_LINK_OFFSET (CIFS_MF_SYMLINK_MD5_OFFSET+(32+1))
+#define CIFS_MF_SYMLINK_LINK_MAXLEN (1024)
+#define CIFS_MF_SYMLINK_FILE_SIZE \
+	(CIFS_MF_SYMLINK_LINK_OFFSET + CIFS_MF_SYMLINK_LINK_MAXLEN)
+
+#define CIFS_MF_SYMLINK_LEN_FORMAT "XSym\n%04u\n"
+#define CIFS_MF_SYMLINK_MD5_FORMAT "%16phN\n"
+#define CIFS_MF_SYMLINK_MD5_ARGS(md5_hash) md5_hash
+
+static int
+parse_mf_symlink(const u8 *buf, unsigned int buf_len, unsigned int *_link_len,
+		 char **_link_str)
+{
+	int rc;
+	unsigned int link_len;
+	const char *md5_str1;
+	const char *link_str;
+	u8 md5_hash[16];
+	char md5_str2[34];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	md5_str1 = (const char *)&buf[CIFS_MF_SYMLINK_MD5_OFFSET];
+	link_str = (const char *)&buf[CIFS_MF_SYMLINK_LINK_OFFSET];
+
+	rc = sscanf(buf, CIFS_MF_SYMLINK_LEN_FORMAT, &link_len);
+	if (rc != 1)
+		return -EINVAL;
+
+	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
+		return -EINVAL;
+
+	md5(link_str, link_len, md5_hash);
+
+	scnprintf(md5_str2, sizeof(md5_str2),
+		  CIFS_MF_SYMLINK_MD5_FORMAT,
+		  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	if (strncmp(md5_str1, md5_str2, 17) != 0)
+		return -EINVAL;
+
+	if (_link_str) {
+		*_link_str = kstrndup(link_str, link_len, GFP_KERNEL);
+		if (!*_link_str)
+			return -ENOMEM;
+	}
+
+	*_link_len = link_len;
+	return 0;
+}
+
+static int
+format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
+{
+	unsigned int link_len;
+	unsigned int ofs;
+	u8 md5_hash[16];
+
+	if (buf_len != CIFS_MF_SYMLINK_FILE_SIZE)
+		return -EINVAL;
+
+	link_len = strlen(link_str);
+
+	if (link_len > CIFS_MF_SYMLINK_LINK_MAXLEN)
+		return -ENAMETOOLONG;
+
+	md5(link_str, link_len, md5_hash);
+
+	scnprintf(buf, buf_len,
+		  CIFS_MF_SYMLINK_LEN_FORMAT CIFS_MF_SYMLINK_MD5_FORMAT,
+		  link_len,
+		  CIFS_MF_SYMLINK_MD5_ARGS(md5_hash));
+
+	ofs = CIFS_MF_SYMLINK_LINK_OFFSET;
+	memcpy(buf + ofs, link_str, link_len);
+
+	ofs += link_len;
+	if (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = '\n';
+		ofs++;
+	}
+
+	while (ofs < CIFS_MF_SYMLINK_FILE_SIZE) {
+		buf[ofs] = ' ';
+		ofs++;
+	}
+
+	return 0;
+}
+
+bool
+couldbe_mf_symlink(const struct cifs_fattr *fattr)
+{
+	if (!S_ISREG(fattr->cf_mode))
+		/* it's not a symlink */
+		return false;
+
+	if (fattr->cf_eof != CIFS_MF_SYMLINK_FILE_SIZE)
+		/* it's not a symlink */
+		return false;
+
+	return true;
+}
+
+static int
+create_mf_symlink(const unsigned int xid, struct cifs_tcon *tcon,
+		  struct cifs_sb_info *cifs_sb, const char *fromName,
+		  const char *toName)
+{
+	int rc;
+	u8 *buf;
+	unsigned int bytes_written = 0;
+
+	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	rc = format_mf_symlink(buf, CIFS_MF_SYMLINK_FILE_SIZE, toName);
+	if (rc)
+		goto out;
+
+	if (tcon->ses->server->ops->create_mf_symlink)
+		rc = tcon->ses->server->ops->create_mf_symlink(xid, tcon,
+					cifs_sb, fromName, buf, &bytes_written);
+	else
+		rc = -EOPNOTSUPP;
+
+	if (rc)
+		goto out;
+
+	if (bytes_written != CIFS_MF_SYMLINK_FILE_SIZE)
+		rc = smb_EIO2(smb_eio_trace_symlink_file_size,
+			      bytes_written, CIFS_MF_SYMLINK_FILE_SIZE);
+out:
+	kfree(buf);
+	return rc;
+}
+
+int
+check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
+		 struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr,
+		 const unsigned char *path)
+{
+	int rc;
+	u8 *buf = NULL;
+	unsigned int link_len = 0;
+	unsigned int bytes_read = 0;
+	char *symlink = NULL;
+
+	if (!couldbe_mf_symlink(fattr))
+		/* it's not a symlink */
+		return 0;
+
+	buf = kmalloc(CIFS_MF_SYMLINK_FILE_SIZE, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (tcon->ses->server->ops->query_mf_symlink)
+		rc = tcon->ses->server->ops->query_mf_symlink(xid, tcon,
+					      cifs_sb, path, buf, &bytes_read);
+	else
+		rc = -ENOSYS;
+
+	if (rc)
+		goto out;
+
+	if (bytes_read == 0) /* not a symlink */
+		goto out;
+
+	rc = parse_mf_symlink(buf, bytes_read, &link_len, &symlink);
+	if (rc == -EINVAL) {
+		/* it's not a symlink */
+		rc = 0;
+		goto out;
+	}
+
+	if (rc != 0)
+		goto out;
+
+	/* it is a symlink */
+	fattr->cf_eof = link_len;
+	fattr->cf_mode &= ~S_IFMT;
+	fattr->cf_mode |= S_IFLNK | S_IRWXU | S_IRWXG | S_IRWXO;
+	fattr->cf_dtype = DT_LNK;
+	fattr->cf_symlink_target = symlink;
+out:
+	kfree(buf);
+	return rc;
+}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+/*
+ * SMB 1.0 Protocol specific functions
+ */
+
+int
+cifs_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
+		      struct cifs_sb_info *cifs_sb, const unsigned char *path,
+		      char *pbuf, unsigned int *pbytes_read)
+{
+	int rc;
+	int oplock = 0;
+	struct cifs_fid fid;
+	struct cifs_open_parms oparms;
+	struct cifs_io_parms io_parms = {0};
+	int buf_type = CIFS_NO_BUFFER;
+	struct cifs_open_info_data query_data = {};
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.desired_access = GENERIC_READ,
+		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
+		.disposition = FILE_OPEN,
+		.path = path,
+		.fid = &fid,
+	};
+
+	rc = tcon->ses->server->ops->open(xid, &oparms, &oplock, &query_data);
+	if (rc)
+		return rc;
+
+	if (query_data.fi.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
+		rc = -ENOENT;
+		/* it's not a symlink */
+		goto out;
+	}
+
+	io_parms.netfid = fid.netfid;
+	io_parms.pid = current->tgid;
+	io_parms.tcon = tcon;
+	io_parms.offset = 0;
+	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
+
+	rc = CIFSSMBRead(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
+out:
+	CIFSSMBClose(xid, tcon, fid.netfid);
+	return rc;
+}
+
+int
+cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
+		       struct cifs_sb_info *cifs_sb, const unsigned char *path,
+		       char *pbuf, unsigned int *pbytes_written)
+{
+	int rc;
+	int oplock = 0;
+	struct cifs_fid fid;
+	struct cifs_open_parms oparms;
+	struct cifs_io_parms io_parms = {0};
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.desired_access = GENERIC_WRITE,
+		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
+		.disposition = FILE_CREATE,
+		.path = path,
+		.fid = &fid,
+	};
+
+	rc = tcon->ses->server->ops->open(xid, &oparms, &oplock, NULL);
+	if (rc)
+		return rc;
+
+	io_parms.netfid = fid.netfid;
+	io_parms.pid = current->tgid;
+	io_parms.tcon = tcon;
+	io_parms.offset = 0;
+	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
+
+	rc = CIFSSMBWrite(xid, &io_parms, pbytes_written, pbuf);
+	CIFSSMBClose(xid, tcon, fid.netfid);
+	return rc;
+}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+
+/*
+ * SMB 2.1/SMB3 Protocol specific functions
+ */
+int
+smb3_query_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
+		      struct cifs_sb_info *cifs_sb, const unsigned char *path,
+		      char *pbuf, unsigned int *pbytes_read)
+{
+	int rc;
+	struct cifs_fid fid;
+	struct cifs_open_parms oparms;
+	struct cifs_io_parms io_parms = {0};
+	int buf_type = CIFS_NO_BUFFER;
+	__le16 *utf16_path;
+	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+	struct cifs_open_info_data data = {};
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.path = path,
+		.desired_access = GENERIC_READ,
+		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
+		.disposition = FILE_OPEN,
+		.fid = &fid,
+	};
+
+	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
+	if (utf16_path == NULL)
+		return -ENOMEM;
+
+	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, &data, NULL,
+		       NULL, NULL);
+	if (rc)
+		goto qmf_out_open_fail;
+
+	if (data.fi.EndOfFile != cpu_to_le64(CIFS_MF_SYMLINK_FILE_SIZE)) {
+		/* it's not a symlink */
+		rc = -ENOENT; /* Is there a better rc to return? */
+		goto qmf_out;
+	}
+
+	io_parms.netfid = fid.netfid;
+	io_parms.pid = current->tgid;
+	io_parms.tcon = tcon;
+	io_parms.offset = 0;
+	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
+	io_parms.persistent_fid = fid.persistent_fid;
+	io_parms.volatile_fid = fid.volatile_fid;
+	rc = SMB2_read(xid, &io_parms, pbytes_read, &pbuf, &buf_type);
+qmf_out:
+	SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+qmf_out_open_fail:
+	kfree(utf16_path);
+	return rc;
+}
+
+int
+smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
+		       struct cifs_sb_info *cifs_sb, const unsigned char *path,
+		       char *pbuf, unsigned int *pbytes_written)
+{
+	int rc;
+	struct cifs_fid fid;
+	struct cifs_open_parms oparms;
+	struct cifs_io_parms io_parms = {0};
+	__le16 *utf16_path;
+	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
+	struct kvec iov[2];
+
+	cifs_dbg(FYI, "%s: path: %s\n", __func__, path);
+
+	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
+	if (!utf16_path)
+		return -ENOMEM;
+
+	oparms = (struct cifs_open_parms) {
+		.tcon = tcon,
+		.cifs_sb = cifs_sb,
+		.path = path,
+		.desired_access = GENERIC_WRITE,
+		.create_options = cifs_create_options(cifs_sb, CREATE_NOT_DIR),
+		.disposition = FILE_CREATE,
+		.fid = &fid,
+		.mode = 0644,
+	};
+
+	rc = SMB2_open(xid, &oparms, utf16_path, &oplock, NULL, NULL,
+		       NULL, NULL);
+	if (rc) {
+		kfree(utf16_path);
+		return rc;
+	}
+
+	io_parms.netfid = fid.netfid;
+	io_parms.pid = current->tgid;
+	io_parms.tcon = tcon;
+	io_parms.offset = 0;
+	io_parms.length = CIFS_MF_SYMLINK_FILE_SIZE;
+	io_parms.persistent_fid = fid.persistent_fid;
+	io_parms.volatile_fid = fid.volatile_fid;
+
+	/* iov[0] is reserved for smb header */
+	iov[1].iov_base = pbuf;
+	iov[1].iov_len = CIFS_MF_SYMLINK_FILE_SIZE;
+
+	rc = SMB2_write(xid, &io_parms, pbytes_written, iov, 1);
+
+	/* Make sure we wrote all of the symlink data */
+	if ((rc == 0) && (*pbytes_written != CIFS_MF_SYMLINK_FILE_SIZE))
+		rc = smb_EIO2(smb_eio_trace_short_symlink_write,
+			      *pbytes_written, CIFS_MF_SYMLINK_FILE_SIZE);
+
+	SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
+
+	kfree(utf16_path);
+	return rc;
+}
+
+/*
+ * M-F Symlink Functions - End
+ */
+
+int
+cifs_hardlink(struct dentry *old_file, struct inode *inode,
+	      struct dentry *direntry)
+{
+	int rc = -EACCES;
+	unsigned int xid;
+	const char *from_name, *to_name;
+	void *page1, *page2;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct tcon_link *tlink;
+	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
+	struct cifsInodeInfo *cifsInode;
+
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return smb_EIO(smb_eio_trace_forced_shutdown);
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+	tcon = tlink_tcon(tlink);
+
+	xid = get_xid();
+	page1 = alloc_dentry_path();
+	page2 = alloc_dentry_path();
+
+	from_name = build_path_from_dentry(old_file, page1);
+	if (IS_ERR(from_name)) {
+		rc = PTR_ERR(from_name);
+		goto cifs_hl_exit;
+	}
+	to_name = build_path_from_dentry(direntry, page2);
+	if (IS_ERR(to_name)) {
+		rc = PTR_ERR(to_name);
+		goto cifs_hl_exit;
+	}
+
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+	if (tcon->unix_ext)
+		rc = CIFSUnixCreateHardLink(xid, tcon, from_name, to_name,
+					    cifs_sb->local_nls,
+					    cifs_remap(cifs_sb));
+	else {
+#else
+	{
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+		server = tcon->ses->server;
+		if (!server->ops->create_hardlink) {
+			rc = -ENOSYS;
+			goto cifs_hl_exit;
+		}
+		rc = server->ops->create_hardlink(xid, tcon, old_file,
+						  from_name, to_name, cifs_sb);
+		if ((rc == -EIO) || (rc == -EINVAL))
+			rc = -EOPNOTSUPP;
+	}
+
+	d_drop(direntry);	/* force new lookup from server of target */
+
+	/*
+	 * if source file is cached (oplocked) revalidate will not go to server
+	 * until the file is closed or oplock broken so update nlinks locally
+	 */
+	if (d_really_is_positive(old_file)) {
+		cifsInode = CIFS_I(d_inode(old_file));
+		if (rc == 0) {
+			clear_bit(CIFS_INO_TMPFILE, &cifsInode->flags);
+			spin_lock(&d_inode(old_file)->i_lock);
+			inc_nlink(d_inode(old_file));
+			spin_unlock(&d_inode(old_file)->i_lock);
+
+			/*
+			 * parent dir timestamps will update from srv within a
+			 * second, would it really be worth it to set the parent
+			 * dir cifs inode time to zero to force revalidate
+			 * (faster) for it too?
+			 */
+		}
+		/*
+		 * if not oplocked will force revalidate to get info on source
+		 * file from srv.  Note Samba server prior to 4.2 has bug -
+		 * not updating src file ctime on hardlinks but Windows servers
+		 * handle it properly
+		 */
+		cifsInode->time = 0;
+
+		/*
+		 * Will update parent dir timestamps from srv within a second.
+		 * Would it really be worth it to set the parent dir (cifs
+		 * inode) time field to zero to force revalidate on parent
+		 * directory faster ie
+		 *
+		 * CIFS_I(inode)->time = 0;
+		 */
+	}
+
+cifs_hl_exit:
+	free_dentry_path(page1);
+	free_dentry_path(page2);
+	free_xid(xid);
+	cifs_put_tlink(tlink);
+	return rc;
+}
+
+int
+cifs_symlink(struct mnt_idmap *idmap, struct inode *inode,
+	     struct dentry *direntry, const char *symname)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode);
+	struct inode *newinode = NULL;
+	struct tcon_link *tlink;
+	struct cifs_tcon *pTcon;
+	const char *full_path;
+	int rc = -EOPNOTSUPP;
+	unsigned int sbflags;
+	unsigned int xid;
+	void *page;
+
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return smb_EIO(smb_eio_trace_forced_shutdown);
+
+	page = alloc_dentry_path();
+	if (!page)
+		return -ENOMEM;
+
+	xid = get_xid();
+
+	tlink = cifs_sb_tlink(cifs_sb);
+	if (IS_ERR(tlink)) {
+		rc = PTR_ERR(tlink);
+		/* BB could be clearer if skipped put_tlink on error here, but harmless */
+		goto symlink_exit;
+	}
+	pTcon = tlink_tcon(tlink);
+
+	full_path = build_path_from_dentry(direntry, page);
+	if (IS_ERR(full_path)) {
+		rc = PTR_ERR(full_path);
+		goto symlink_exit;
+	}
+
+	cifs_dbg(FYI, "Full path: %s\n", full_path);
+	cifs_dbg(FYI, "symname is %s\n", symname);
+
+	/* BB what if DFS and this volume is on different share? BB */
+	sbflags = cifs_sb_flags(cifs_sb);
+	rc = -EOPNOTSUPP;
+	switch (cifs_symlink_type(cifs_sb)) {
+	case CIFS_SYMLINK_TYPE_UNIX:
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
+		if (pTcon->unix_ext) {
+			rc = CIFSUnixCreateSymLink(xid, pTcon, full_path,
+						   symname,
+						   cifs_sb->local_nls,
+						   cifs_remap(cifs_sb));
+		}
+#endif /* CONFIG_CIFS_ALLOW_INSECURE_LEGACY */
+		break;
+
+	case CIFS_SYMLINK_TYPE_MFSYMLINKS:
+		if (sbflags & CIFS_MOUNT_MF_SYMLINKS) {
+			rc = create_mf_symlink(xid, pTcon, cifs_sb,
+					       full_path, symname);
+		}
+		break;
+
+	case CIFS_SYMLINK_TYPE_SFU:
+		if (sbflags & CIFS_MOUNT_UNX_EMUL) {
+			rc = __cifs_sfu_make_node(xid, inode, direntry, pTcon,
+						  full_path, S_IFLNK,
+						  0, symname);
+		}
+		break;
+
+	case CIFS_SYMLINK_TYPE_NATIVE:
+	case CIFS_SYMLINK_TYPE_NFS:
+	case CIFS_SYMLINK_TYPE_WSL:
+		if (CIFS_REPARSE_SUPPORT(pTcon)) {
+			rc = create_reparse_symlink(xid, inode, direntry, pTcon,
+						    full_path, symname);
+			goto symlink_exit;
+		}
+		break;
+	default:
+		break;
+	}
+
+	if (rc == 0) {
+		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 {
+			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",
+				 rc);
+		} else {
+			d_instantiate(direntry, newinode);
+		}
+	}
+symlink_exit:
+	free_dentry_path(page);
+	cifs_put_tlink(tlink);
+	free_xid(xid);
+	return rc;
+}