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-rw-r--r--fs/jffs2/compr.c418
1 files changed, 418 insertions, 0 deletions
diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c
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+++ b/fs/jffs2/compr.c
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+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
+ * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
+ * University of Szeged, Hungary
+ *
+ * Created by Arjan van de Ven <arjan@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include "compr.h"
+
+static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
+
+/* Available compressors are on this list */
+static LIST_HEAD(jffs2_compressor_list);
+
+/* Actual compression mode */
+static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
+
+/* Statistics for blocks stored without compression */
+static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
+
+
+/*
+ * Return 1 to use this compression
+ */
+static int jffs2_is_best_compression(struct jffs2_compressor *this,
+ struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
+{
+ switch (jffs2_compression_mode) {
+ case JFFS2_COMPR_MODE_SIZE:
+ if (bestsize > size)
+ return 1;
+ return 0;
+ case JFFS2_COMPR_MODE_FAVOURLZO:
+ if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
+ return 1;
+ if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
+ return 1;
+ if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
+ return 1;
+ if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
+ return 1;
+
+ return 0;
+ }
+ /* Shouldn't happen */
+ return 0;
+}
+
+/*
+ * jffs2_selected_compress:
+ * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB).
+ * If 0, just take the first available compression mode.
+ * @data_in: Pointer to uncompressed data
+ * @cpage_out: Pointer to returned pointer to buffer for compressed data
+ * @datalen: On entry, holds the amount of data available for compression.
+ * On exit, expected to hold the amount of data actually compressed.
+ * @cdatalen: On entry, holds the amount of space available for compressed
+ * data. On exit, expected to hold the actual size of the compressed
+ * data.
+ *
+ * Returns: the compression type used. Zero is used to show that the data
+ * could not be compressed; probably because we couldn't find the requested
+ * compression mode.
+ */
+static int jffs2_selected_compress(u8 compr, unsigned char *data_in,
+ unsigned char **cpage_out, u32 *datalen, u32 *cdatalen)
+{
+ struct jffs2_compressor *this;
+ int err, ret = JFFS2_COMPR_NONE;
+ uint32_t orig_slen, orig_dlen;
+ char *output_buf;
+
+ output_buf = kmalloc(*cdatalen, GFP_KERNEL);
+ if (!output_buf) {
+ pr_warn("No memory for compressor allocation. Compression failed.\n");
+ return ret;
+ }
+ orig_slen = *datalen;
+ orig_dlen = *cdatalen;
+ spin_lock(&jffs2_compressor_list_lock);
+ list_for_each_entry(this, &jffs2_compressor_list, list) {
+ /* Skip decompress-only and disabled modules */
+ if (!this->compress || this->disabled)
+ continue;
+
+ /* Skip if not the desired compression type */
+ if (compr && (compr != this->compr))
+ continue;
+
+ /*
+ * Either compression type was unspecified, or we found our
+ * compressor; either way, we're good to go.
+ */
+ this->usecount++;
+ spin_unlock(&jffs2_compressor_list_lock);
+
+ *datalen = orig_slen;
+ *cdatalen = orig_dlen;
+ err = this->compress(data_in, output_buf, datalen, cdatalen);
+
+ spin_lock(&jffs2_compressor_list_lock);
+ this->usecount--;
+ if (!err) {
+ /* Success */
+ ret = this->compr;
+ this->stat_compr_blocks++;
+ this->stat_compr_orig_size += *datalen;
+ this->stat_compr_new_size += *cdatalen;
+ break;
+ }
+ }
+ spin_unlock(&jffs2_compressor_list_lock);
+ if (ret == JFFS2_COMPR_NONE)
+ kfree(output_buf);
+ else
+ *cpage_out = output_buf;
+
+ return ret;
+}
+
+/* jffs2_compress:
+ * @data_in: Pointer to uncompressed data
+ * @cpage_out: Pointer to returned pointer to buffer for compressed data
+ * @datalen: On entry, holds the amount of data available for compression.
+ * On exit, expected to hold the amount of data actually compressed.
+ * @cdatalen: On entry, holds the amount of space available for compressed
+ * data. On exit, expected to hold the actual size of the compressed
+ * data.
+ *
+ * Returns: Lower byte to be stored with data indicating compression type used.
+ * Zero is used to show that the data could not be compressed - the
+ * compressed version was actually larger than the original.
+ * Upper byte will be used later. (soon)
+ *
+ * If the cdata buffer isn't large enough to hold all the uncompressed data,
+ * jffs2_compress should compress as much as will fit, and should set
+ * *datalen accordingly to show the amount of data which were compressed.
+ */
+uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
+ unsigned char *data_in, unsigned char **cpage_out,
+ uint32_t *datalen, uint32_t *cdatalen)
+{
+ int ret = JFFS2_COMPR_NONE;
+ int mode, compr_ret;
+ struct jffs2_compressor *this, *best=NULL;
+ unsigned char *output_buf = NULL, *tmp_buf;
+ uint32_t orig_slen, orig_dlen;
+ uint32_t best_slen=0, best_dlen=0;
+
+ if (c->mount_opts.override_compr)
+ mode = c->mount_opts.compr;
+ else
+ mode = jffs2_compression_mode;
+
+ switch (mode) {
+ case JFFS2_COMPR_MODE_NONE:
+ break;
+ case JFFS2_COMPR_MODE_PRIORITY:
+ ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
+ cdatalen);
+ break;
+ case JFFS2_COMPR_MODE_SIZE:
+ case JFFS2_COMPR_MODE_FAVOURLZO:
+ orig_slen = *datalen;
+ orig_dlen = *cdatalen;
+ spin_lock(&jffs2_compressor_list_lock);
+ list_for_each_entry(this, &jffs2_compressor_list, list) {
+ /* Skip decompress-only backwards-compatibility and disabled modules */
+ if ((!this->compress)||(this->disabled))
+ continue;
+ /* Allocating memory for output buffer if necessary */
+ if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
+ spin_unlock(&jffs2_compressor_list_lock);
+ kfree(this->compr_buf);
+ spin_lock(&jffs2_compressor_list_lock);
+ this->compr_buf_size=0;
+ this->compr_buf=NULL;
+ }
+ if (!this->compr_buf) {
+ spin_unlock(&jffs2_compressor_list_lock);
+ tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
+ spin_lock(&jffs2_compressor_list_lock);
+ if (!tmp_buf) {
+ pr_warn("No memory for compressor allocation. (%d bytes)\n",
+ orig_slen);
+ continue;
+ }
+ else {
+ this->compr_buf = tmp_buf;
+ this->compr_buf_size = orig_slen;
+ }
+ }
+ this->usecount++;
+ spin_unlock(&jffs2_compressor_list_lock);
+ *datalen = orig_slen;
+ *cdatalen = orig_dlen;
+ compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
+ spin_lock(&jffs2_compressor_list_lock);
+ this->usecount--;
+ if (!compr_ret) {
+ if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
+ && (*cdatalen < *datalen)) {
+ best_dlen = *cdatalen;
+ best_slen = *datalen;
+ best = this;
+ }
+ }
+ }
+ if (best_dlen) {
+ *cdatalen = best_dlen;
+ *datalen = best_slen;
+ output_buf = best->compr_buf;
+ best->compr_buf = NULL;
+ best->compr_buf_size = 0;
+ best->stat_compr_blocks++;
+ best->stat_compr_orig_size += best_slen;
+ best->stat_compr_new_size += best_dlen;
+ ret = best->compr;
+ *cpage_out = output_buf;
+ }
+ spin_unlock(&jffs2_compressor_list_lock);
+ break;
+ case JFFS2_COMPR_MODE_FORCELZO:
+ ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in,
+ cpage_out, datalen, cdatalen);
+ break;
+ case JFFS2_COMPR_MODE_FORCEZLIB:
+ ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in,
+ cpage_out, datalen, cdatalen);
+ break;
+ default:
+ pr_err("unknown compression mode\n");
+ }
+
+ if (ret == JFFS2_COMPR_NONE) {
+ *cpage_out = data_in;
+ *datalen = *cdatalen;
+ none_stat_compr_blocks++;
+ none_stat_compr_size += *datalen;
+ }
+ return ret;
+}
+
+int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
+ uint16_t comprtype, unsigned char *cdata_in,
+ unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
+{
+ struct jffs2_compressor *this;
+ int ret;
+
+ /* Older code had a bug where it would write non-zero 'usercompr'
+ fields. Deal with it. */
+ if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
+ comprtype &= 0xff;
+
+ switch (comprtype & 0xff) {
+ case JFFS2_COMPR_NONE:
+ /* This should be special-cased elsewhere, but we might as well deal with it */
+ memcpy(data_out, cdata_in, datalen);
+ none_stat_decompr_blocks++;
+ break;
+ case JFFS2_COMPR_ZERO:
+ memset(data_out, 0, datalen);
+ break;
+ default:
+ spin_lock(&jffs2_compressor_list_lock);
+ list_for_each_entry(this, &jffs2_compressor_list, list) {
+ if (comprtype == this->compr) {
+ this->usecount++;
+ spin_unlock(&jffs2_compressor_list_lock);
+ ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
+ spin_lock(&jffs2_compressor_list_lock);
+ if (ret) {
+ pr_warn("Decompressor \"%s\" returned %d\n",
+ this->name, ret);
+ }
+ else {
+ this->stat_decompr_blocks++;
+ }
+ this->usecount--;
+ spin_unlock(&jffs2_compressor_list_lock);
+ return ret;
+ }
+ }
+ pr_warn("compression type 0x%02x not available\n", comprtype);
+ spin_unlock(&jffs2_compressor_list_lock);
+ return -EIO;
+ }
+ return 0;
+}
+
+int jffs2_register_compressor(struct jffs2_compressor *comp)
+{
+ struct jffs2_compressor *this;
+
+ if (!comp->name) {
+ pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
+ return -1;
+ }
+ comp->compr_buf_size=0;
+ comp->compr_buf=NULL;
+ comp->usecount=0;
+ comp->stat_compr_orig_size=0;
+ comp->stat_compr_new_size=0;
+ comp->stat_compr_blocks=0;
+ comp->stat_decompr_blocks=0;
+ jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);
+
+ spin_lock(&jffs2_compressor_list_lock);
+
+ list_for_each_entry(this, &jffs2_compressor_list, list) {
+ if (this->priority < comp->priority) {
+ list_add(&comp->list, this->list.prev);
+ goto out;
+ }
+ }
+ list_add_tail(&comp->list, &jffs2_compressor_list);
+out:
+ D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
+ printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
+ })
+
+ spin_unlock(&jffs2_compressor_list_lock);
+
+ return 0;
+}
+
+int jffs2_unregister_compressor(struct jffs2_compressor *comp)
+{
+ D2(struct jffs2_compressor *this);
+
+ jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);
+
+ spin_lock(&jffs2_compressor_list_lock);
+
+ if (comp->usecount) {
+ spin_unlock(&jffs2_compressor_list_lock);
+ pr_warn("Compressor module is in use. Unregister failed.\n");
+ return -1;
+ }
+ list_del(&comp->list);
+
+ D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
+ printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
+ })
+ spin_unlock(&jffs2_compressor_list_lock);
+ return 0;
+}
+
+void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
+{
+ if (orig != comprbuf)
+ kfree(comprbuf);
+}
+
+int __init jffs2_compressors_init(void)
+{
+/* Registering compressors */
+#ifdef CONFIG_JFFS2_ZLIB
+ jffs2_zlib_init();
+#endif
+#ifdef CONFIG_JFFS2_RTIME
+ jffs2_rtime_init();
+#endif
+#ifdef CONFIG_JFFS2_RUBIN
+ jffs2_rubinmips_init();
+ jffs2_dynrubin_init();
+#endif
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_init();
+#endif
+/* Setting default compression mode */
+#ifdef CONFIG_JFFS2_CMODE_NONE
+ jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
+ jffs2_dbg(1, "default compression mode: none\n");
+#else
+#ifdef CONFIG_JFFS2_CMODE_SIZE
+ jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
+ jffs2_dbg(1, "default compression mode: size\n");
+#else
+#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
+ jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
+ jffs2_dbg(1, "default compression mode: favourlzo\n");
+#else
+ jffs2_dbg(1, "default compression mode: priority\n");
+#endif
+#endif
+#endif
+ return 0;
+}
+
+int jffs2_compressors_exit(void)
+{
+/* Unregistering compressors */
+#ifdef CONFIG_JFFS2_LZO
+ jffs2_lzo_exit();
+#endif
+#ifdef CONFIG_JFFS2_RUBIN
+ jffs2_dynrubin_exit();
+ jffs2_rubinmips_exit();
+#endif
+#ifdef CONFIG_JFFS2_RTIME
+ jffs2_rtime_exit();
+#endif
+#ifdef CONFIG_JFFS2_ZLIB
+ jffs2_zlib_exit();
+#endif
+ return 0;
+}
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