--- linux-4.9.37/fs/jffs2/compr_lzma.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-4.9.y/fs/jffs2/compr_lzma.c	2021-06-07 13:01:34.000000000 +0300
@@ -0,0 +1,125 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ * JFFS2 wrapper to the LZMA C SDK
+ *
+ */
+
+#include <linux/lzma.h>
+#include "compr.h"
+
+#ifdef __KERNEL__
+	static DEFINE_MUTEX(deflate_mutex);
+#endif
+
+CLzmaEncHandle *p;
+Byte propsEncoded[LZMA_PROPS_SIZE];
+SizeT propsSize = sizeof(propsEncoded);
+
+STATIC void lzma_free_workspace(void)
+{
+	LzmaEnc_Destroy(p, &lzma_alloc, &lzma_alloc);
+}
+
+STATIC int INIT lzma_alloc_workspace(CLzmaEncProps *props)
+{
+	if ((p = (CLzmaEncHandle *)LzmaEnc_Create(&lzma_alloc)) == NULL) {
+		PRINT_ERROR("Failed to allocate lzma deflate workspace\n");
+		return -ENOMEM;
+	}
+
+	if (LzmaEnc_SetProps(p, props) != SZ_OK) {
+		lzma_free_workspace();
+		return -1;
+	}
+	
+	if (LzmaEnc_WriteProperties(p, propsEncoded, &propsSize) != SZ_OK) {
+		lzma_free_workspace();
+		return -1;
+	}
+
+	return 0;
+}
+
+STATIC int jffs2_lzma_compress(unsigned char *data_in, unsigned char *cpage_out,
+			      uint32_t *sourcelen, uint32_t *dstlen)
+{
+	SizeT compress_size = (SizeT)(*dstlen);
+	int ret;
+
+#ifdef __KERNEL__
+	mutex_lock(&deflate_mutex);
+#endif
+
+	ret = LzmaEnc_MemEncode(p, cpage_out, &compress_size, data_in, *sourcelen,
+		0, NULL, &lzma_alloc, &lzma_alloc);
+
+#ifdef __KERNEL__
+	mutex_unlock(&deflate_mutex);
+#endif
+
+	if (ret != SZ_OK)
+		return -1;
+
+	*dstlen = (uint32_t)compress_size;
+
+	return 0;
+}
+
+STATIC int jffs2_lzma_decompress(unsigned char *data_in, unsigned char *cpage_out,
+				 uint32_t srclen, uint32_t destlen)
+{
+	int ret;
+	SizeT dl = (SizeT)destlen;
+	SizeT sl = (SizeT)srclen;
+	ELzmaStatus status;
+	
+	ret = LzmaDecode(cpage_out, &dl, data_in, &sl, propsEncoded,
+		propsSize, LZMA_FINISH_ANY, &status, &lzma_alloc);
+
+	if (ret != SZ_OK || status == LZMA_STATUS_NOT_FINISHED || dl != (SizeT)destlen)
+		return -1;
+
+	return 0;
+}
+
+static struct jffs2_compressor jffs2_lzma_comp = {
+	.priority = JFFS2_LZMA_PRIORITY,
+	.name = "lzma",
+	.compr = JFFS2_COMPR_LZMA,
+	.compress = &jffs2_lzma_compress,
+	.decompress = &jffs2_lzma_decompress,
+	.disabled = 0,
+};
+
+int INIT jffs2_lzma_init(void)
+{
+	int ret;
+	CLzmaEncProps props;
+	LzmaEncProps_Init(&props);
+
+	props.dictSize = LZMA_BEST_DICT(0x2000);
+	props.level = LZMA_BEST_LEVEL;
+	props.lc = LZMA_BEST_LC;
+	props.lp = LZMA_BEST_LP;
+	props.pb = LZMA_BEST_PB;
+	props.fb = LZMA_BEST_FB;
+
+	ret = lzma_alloc_workspace(&props);
+	if (ret < 0)
+		return ret;
+
+	ret = jffs2_register_compressor(&jffs2_lzma_comp);
+	if (ret)
+		lzma_free_workspace();
+	
+	return ret;
+}
+
+void jffs2_lzma_exit(void)
+{
+	jffs2_unregister_compressor(&jffs2_lzma_comp);
+	lzma_free_workspace();
+}