1 files changed, 253 insertions, 0 deletions
diff --git a/fs/ubifs/compress.c b/fs/ubifs/compress.c
new file mode 100644
index 0000000..5bb51da
--- /dev/null
+++ b/fs/ubifs/compress.c
@@ -0,0 +1,253 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ * Copyright (C) 2006, 2007 University of Szeged, Hungary
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ *          Zoltan Sogor
+ */
+
+/*
+ * This file provides a single place to access to compression and
+ * decompression.
+ */
+
+#include <linux/crypto.h>
+#include "ubifs.h"
+
+/* Fake description object for the "none" compressor */
+static struct ubifs_compressor none_compr = {
+	.compr_type = UBIFS_COMPR_NONE,
+	.name = "no compression",
+	.capi_name = "",
+};
+
+#ifdef CONFIG_UBIFS_FS_LZO
+static DEFINE_MUTEX(lzo_mutex);
+
+static struct ubifs_compressor lzo_compr = {
+	.compr_type = UBIFS_COMPR_LZO,
+	.comp_mutex = &lzo_mutex,
+	.name = "LZO",
+	.capi_name = "lzo",
+};
+#else
+static struct ubifs_compressor lzo_compr = {
+	.compr_type = UBIFS_COMPR_LZO,
+	.name = "LZO",
+};
+#endif
+
+#ifdef CONFIG_UBIFS_FS_ZLIB
+static DEFINE_MUTEX(deflate_mutex);
+static DEFINE_MUTEX(inflate_mutex);
+
+static struct ubifs_compressor zlib_compr = {
+	.compr_type = UBIFS_COMPR_ZLIB,
+	.comp_mutex = &deflate_mutex,
+	.decomp_mutex = &inflate_mutex,
+	.name = "zlib",
+	.capi_name = "deflate",
+};
+#else
+static struct ubifs_compressor zlib_compr = {
+	.compr_type = UBIFS_COMPR_ZLIB,
+	.name = "zlib",
+};
+#endif
+
+/* All UBIFS compressors */
+struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
+
+/**
+ * ubifs_compress - compress data.
+ * @in_buf: data to compress
+ * @in_len: length of the data to compress
+ * @out_buf: output buffer where compressed data should be stored
+ * @out_len: output buffer length is returned here
+ * @compr_type: type of compression to use on enter, actually used compression
+ *              type on exit
+ *
+ * This function compresses input buffer @in_buf of length @in_len and stores
+ * the result in the output buffer @out_buf and the resulting length in
+ * @out_len. If the input buffer does not compress, it is just copied to the
+ * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
+ * compression error occurred.
+ *
+ * Note, if the input buffer was not compressed, it is copied to the output
+ * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
+		    int *compr_type)
+{
+	int err;
+	struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
+
+	if (*compr_type == UBIFS_COMPR_NONE)
+		goto no_compr;
+
+	/* If the input data is small, do not even try to compress it */
+	if (in_len < UBIFS_MIN_COMPR_LEN)
+		goto no_compr;
+
+	if (compr->comp_mutex)
+		mutex_lock(compr->comp_mutex);
+	err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
+				   out_len);
+	if (compr->comp_mutex)
+		mutex_unlock(compr->comp_mutex);
+	if (unlikely(err)) {
+		ubifs_warn("cannot compress %d bytes, compressor %s, "
+			   "error %d, leave data uncompressed",
+			   in_len, compr->name, err);
+		 goto no_compr;
+	}
+
+	/*
+	 * Presently, we just require that compression results in less data,
+	 * rather than any defined minimum compression ratio or amount.
+	 */
+	if (ALIGN(*out_len, 8) >= ALIGN(in_len, 8))
+		goto no_compr;
+
+	return;
+
+no_compr:
+	memcpy(out_buf, in_buf, in_len);
+	*out_len = in_len;
+	*compr_type = UBIFS_COMPR_NONE;
+}
+
+/**
+ * ubifs_decompress - decompress data.
+ * @in_buf: data to decompress
+ * @in_len: length of the data to decompress
+ * @out_buf: output buffer where decompressed data should
+ * @out_len: output length is returned here
+ * @compr_type: type of compression
+ *
+ * This function decompresses data from buffer @in_buf into buffer @out_buf.
+ * The length of the uncompressed data is returned in @out_len. This functions
+ * returns %0 on success or a negative error code on failure.
+ */
+int ubifs_decompress(const void *in_buf, int in_len, void *out_buf,
+		     int *out_len, int compr_type)
+{
+	int err;
+	struct ubifs_compressor *compr;
+
+	if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
+		ubifs_err("invalid compression type %d", compr_type);
+		return -EINVAL;
+	}
+
+	compr = ubifs_compressors[compr_type];
+
+	if (unlikely(!compr->capi_name)) {
+		ubifs_err("%s compression is not compiled in", compr->name);
+		return -EINVAL;
+	}
+
+	if (compr_type == UBIFS_COMPR_NONE) {
+		memcpy(out_buf, in_buf, in_len);
+		*out_len = in_len;
+		return 0;
+	}
+
+	if (compr->decomp_mutex)
+		mutex_lock(compr->decomp_mutex);
+	err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
+				     out_len);
+	if (compr->decomp_mutex)
+		mutex_unlock(compr->decomp_mutex);
+	if (err)
+		ubifs_err("cannot decompress %d bytes, compressor %s, "
+			  "error %d", in_len, compr->name, err);
+
+	return err;
+}
+
+/**
+ * compr_init - initialize a compressor.
+ * @compr: compressor description object
+ *
+ * This function initializes the requested compressor and returns zero in case
+ * of success or a negative error code in case of failure.
+ */
+static int __init compr_init(struct ubifs_compressor *compr)
+{
+	if (compr->capi_name) {
+		compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
+		if (IS_ERR(compr->cc)) {
+			ubifs_err("cannot initialize compressor %s, error %ld",
+				  compr->name, PTR_ERR(compr->cc));
+			return PTR_ERR(compr->cc);
+		}
+	}
+
+	ubifs_compressors[compr->compr_type] = compr;
+	return 0;
+}
+
+/**
+ * compr_exit - de-initialize a compressor.
+ * @compr: compressor description object
+ */
+static void compr_exit(struct ubifs_compressor *compr)
+{
+	if (compr->capi_name)
+		crypto_free_comp(compr->cc);
+	return;
+}
+
+/**
+ * ubifs_compressors_init - initialize UBIFS compressors.
+ *
+ * This function initializes the compressor which were compiled in. Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+int __init ubifs_compressors_init(void)
+{
+	int err;
+
+	err = compr_init(&lzo_compr);
+	if (err)
+		return err;
+
+	err = compr_init(&zlib_compr);
+	if (err)
+		goto out_lzo;
+
+	ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
+	return 0;
+
+out_lzo:
+	compr_exit(&lzo_compr);
+	return err;
+}
+
+/**
+ * ubifs_compressors_exit - de-initialize UBIFS compressors.
+ */
+void __exit ubifs_compressors_exit(void)
+{
+	compr_exit(&lzo_compr);
+	compr_exit(&zlib_compr);
+}