CIFS: make mknod() an smb_version_op

This cleanup removes cifs specific code from SMB2/SMB3 code paths
which is cleaner and easier to maintain as the code to handle
special files is improved.  Below is an example creating special files
using 'sfu' mount option over SMB3 to Windows (with this patch)
(Note that to Samba server, support for saving dos attributes
has to be enabled for the SFU mount option to work).

In the future this will also make implementation of creating
special files as reparse points easier (as Windows NFS server does
for example).

   root@smf-Thinkpad-P51:~# stat -c "%F" /mnt2/char
   character special file

   root@smf-Thinkpad-P51:~# stat -c "%F" /mnt2/block
   block special file

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

1 files changed, 126 insertions, 0 deletions

diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index f0ce27c3c6e4..c711f1f39bf2 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -1027,6 +1027,131 @@ cifs_can_echo(struct TCP_Server_Info *server)
 	return false;
 }
 
+static int
+cifs_make_node(unsigned int xid, struct inode *inode,
+	       struct dentry *dentry, struct cifs_tcon *tcon,
+	       char *full_path, umode_t mode, dev_t dev)
+{
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct inode *newinode = NULL;
+	int rc = -EPERM;
+	int create_options = CREATE_NOT_DIR | CREATE_OPTION_SPECIAL;
+	FILE_ALL_INFO *buf = NULL;
+	struct cifs_io_parms io_parms;
+	__u32 oplock = 0;
+	struct cifs_fid fid;
+	struct cifs_open_parms oparms;
+	unsigned int bytes_written;
+	struct win_dev *pdev;
+	struct kvec iov[2];
+
+	if (tcon->unix_ext) {
+		/*
+		 * SMB1 Unix Extensions: requires server support but
+		 * works with all special files
+		 */
+		struct cifs_unix_set_info_args args = {
+			.mode	= mode & ~current_umask(),
+			.ctime	= NO_CHANGE_64,
+			.atime	= NO_CHANGE_64,
+			.mtime	= NO_CHANGE_64,
+			.device	= dev,
+		};
+		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
+			args.uid = current_fsuid();
+			args.gid = current_fsgid();
+		} else {
+			args.uid = INVALID_UID; /* no change */
+			args.gid = INVALID_GID; /* no change */
+		}
+		rc = CIFSSMBUnixSetPathInfo(xid, tcon, full_path, &args,
+					    cifs_sb->local_nls,
+					    cifs_remap(cifs_sb));
+		if (rc)
+			goto out;
+
+		rc = cifs_get_inode_info_unix(&newinode, full_path,
+					      inode->i_sb, xid);
+
+		if (rc == 0)
+			d_instantiate(dentry, newinode);
+		goto out;
+	}
+
+	/*
+	 * SMB1 SFU emulation: should work with all servers, but only
+	 * support block and char device (no socket & fifo)
+	 */
+	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL))
+		goto out;
+
+	if (!S_ISCHR(mode) && !S_ISBLK(mode))
+		goto out;
+
+	cifs_dbg(FYI, "sfu compat create special file\n");
+
+	buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
+	if (buf == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (backup_cred(cifs_sb))
+		create_options |= CREATE_OPEN_BACKUP_INTENT;
+
+	oparms.tcon = tcon;
+	oparms.cifs_sb = cifs_sb;
+	oparms.desired_access = GENERIC_WRITE;
+	oparms.create_options = create_options;
+	oparms.disposition = FILE_CREATE;
+	oparms.path = full_path;
+	oparms.fid = &fid;
+	oparms.reconnect = false;
+
+	if (tcon->ses->server->oplocks)
+		oplock = REQ_OPLOCK;
+	else
+		oplock = 0;
+	rc = tcon->ses->server->ops->open(xid, &oparms, &oplock, buf);
+	if (rc)
+		goto out;
+
+	/*
+	 * BB Do not bother to decode buf since no local inode yet to put
+	 * timestamps in, but we can reuse it safely.
+	 */
+
+	pdev = (struct win_dev *)buf;
+	io_parms.pid = current->tgid;
+	io_parms.tcon = tcon;
+	io_parms.offset = 0;
+	io_parms.length = sizeof(struct win_dev);
+	iov[1].iov_base = buf;
+	iov[1].iov_len = sizeof(struct win_dev);
+	if (S_ISCHR(mode)) {
+		memcpy(pdev->type, "IntxCHR", 8);
+		pdev->major = cpu_to_le64(MAJOR(dev));
+		pdev->minor = cpu_to_le64(MINOR(dev));
+		rc = tcon->ses->server->ops->sync_write(xid, &fid, &io_parms,
+							&bytes_written, iov, 1);
+	} else if (S_ISBLK(mode)) {
+		memcpy(pdev->type, "IntxBLK", 8);
+		pdev->major = cpu_to_le64(MAJOR(dev));
+		pdev->minor = cpu_to_le64(MINOR(dev));
+		rc = tcon->ses->server->ops->sync_write(xid, &fid, &io_parms,
+							&bytes_written, iov, 1);
+	}
+	tcon->ses->server->ops->close(xid, tcon, &fid);
+	d_drop(dentry);
+
+	/* FIXME: add code here to set EAs */
+out:
+	kfree(buf);
+	return rc;
+}
+
+
+
 struct smb_version_operations smb1_operations = {
 	.send_cancel = send_nt_cancel,
 	.compare_fids = cifs_compare_fids,
@@ -1110,6 +1235,7 @@ struct smb_version_operations smb1_operations = {
 	.get_acl_by_fid = get_cifs_acl_by_fid,
 	.set_acl = set_cifs_acl,
 #endif /* CIFS_ACL */
+	.make_node = cifs_make_node,
 };
 
 struct smb_version_values smb1_values = {