Commit d14bbfff authored by Steve French's avatar Steve French
Browse files

smb3: mark compression as CONFIG_EXPERIMENTAL and fix missing compression operation 



Move SMB3.1.1 compression code into experimental config option,
and fix the compress mount option. Implement unchained LZ77
"plain" compression algorithm as per MS-XCA specification
section "2.3 Plain LZ77 Compression Algorithm Details".

Signed-off-by: default avatarEnzo Matsumiya <ematsumiya@suse.de>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 6795dab4

fs/smb/client/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -204,4 +204,18 @@ config CIFS_ROOT 


	  Most people say N here.



config CIFS_COMPRESSION

	bool "SMB message compression (Experimental)"

	depends on CIFS

	default n

	help

	  Enables over-the-wire message compression for SMB 3.1.1

	  mounts when negotiated with the server.



	  Only write requests with data size >= PAGE_SIZE will be

	  compressed to avoid wasting resources.



	  Say Y here if you want SMB traffic to be compressed.

	  If unsure, say N.



endif

fs/smb/client/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -33,3 +33,5 @@ cifs-$(CONFIG_CIFS_SMB_DIRECT) += smbdirect.o 
cifs-$(CONFIG_CIFS_ROOT) += cifsroot.o



cifs-$(CONFIG_CIFS_ALLOW_INSECURE_LEGACY) += smb1ops.o cifssmb.o



cifs-$(CONFIG_CIFS_COMPRESSION) += compress.o compress/lz77.o

fs/smb/client/cifs_debug.c

+6 −1
Original line number Diff line number Diff line
@@ -349,6 +349,9 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v) 
	seq_printf(m, ",ACL");

#ifdef CONFIG_CIFS_SWN_UPCALL

	seq_puts(m, ",WITNESS");

#endif

#ifdef CONFIG_CIFS_COMPRESSION

	seq_puts(m, ",COMPRESSION");

#endif

	seq_putc(m, '\n');

	seq_printf(m, "CIFSMaxBufSize: %d\n", CIFSMaxBufSize);
@@ -475,7 +478,9 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v) 
		}



		seq_puts(m, "\nCompression: ");

		if (!server->compression.requested)

		if (!IS_ENABLED(CONFIG_CIFS_COMPRESSION))

			seq_puts(m, "no built-in support");

		else if (!server->compression.requested)

			seq_puts(m, "disabled on mount");

		else if (server->compression.enabled)

			seq_printf(m, "enabled (%s)", compression_alg_str(server->compression.alg));

fs/smb/client/cifsglob.h

+2 −1
Original line number Diff line number Diff line
@@ -555,7 +555,7 @@ struct smb_version_operations { 
	bool (*dir_needs_close)(struct cifsFileInfo *);

	long (*fallocate)(struct file *, struct cifs_tcon *, int, loff_t,

			  loff_t);

	/* init transform request - used for encryption for now */

	/* init transform (compress/encrypt) request */

	int (*init_transform_rq)(struct TCP_Server_Info *, int num_rqst,

				 struct smb_rqst *, struct smb_rqst *);

	int (*is_transform_hdr)(void *buf);
@@ -1876,6 +1876,7 @@ static inline bool is_replayable_error(int error) 
#define   CIFS_HAS_CREDITS        0x0400 /* already has credits */

#define   CIFS_TRANSFORM_REQ      0x0800 /* transform request before sending */

#define   CIFS_NO_SRV_RSP         0x1000 /* there is no server response */

#define   CIFS_COMPRESS_REQ       0x4000 /* compress request before sending */



/* Security Flags: indicate type of session setup needed */

#define   CIFSSEC_MAY_SIGN	0x00001

fs/smb/client/compress.c

0 → 100644
+50 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2024, SUSE LLC

 *

 * Authors: Enzo Matsumiya <ematsumiya@suse.de>

 *

 * This file implements I/O compression support for SMB2 messages (SMB 3.1.1 only).

 * See compress/ for implementation details of each algorithm.

 *

 * References:

 * MS-SMB2 "3.1.4.4 Compressing the Message"

 * MS-SMB2 "3.1.5.3 Decompressing the Chained Message"

 * MS-XCA - for details of the supported algorithms

 */

#include <linux/slab.h>

#include <linux/kernel.h>

#include <linux/uio.h>



#include "cifsglob.h"

#include "../common/smb2pdu.h"

#include "cifsproto.h"

#include "smb2proto.h"



#include "compress/lz77.h"

#include "compress.h"



int smb_compress(void *buf, const void *data, size_t *len)

{

	struct smb2_compression_hdr *hdr;

	size_t buf_len, data_len;

	int ret;



	buf_len = sizeof(struct smb2_write_req);

	data_len = *len;

	*len = 0;



	hdr = buf;

	hdr->ProtocolId = SMB2_COMPRESSION_TRANSFORM_ID;

	hdr->OriginalCompressedSegmentSize = cpu_to_le32(data_len);

	hdr->Offset = cpu_to_le32(buf_len);

	hdr->Flags = SMB2_COMPRESSION_FLAG_NONE;

	hdr->CompressionAlgorithm = SMB3_COMPRESS_LZ77;



	/* XXX: add other algs here as they're implemented */

	ret = lz77_compress(data, data_len, buf + SMB_COMPRESS_HDR_LEN + buf_len, &data_len);

	if (!ret)

		*len = SMB_COMPRESS_HDR_LEN + buf_len + data_len;



	return ret;

}