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Date: Sat, 15 Oct 2011 12:50:12 -0700
From: Andres Salomon <dilinger@...ued.net>
To: David Woodhouse <dwmw2@...radead.org>
Cc: linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
Artem Bityutskiy <dedekind1@...il.com>
Subject: [PATCH 2/2] jffs2: add compr=lzo and compr=zlib options
..to allow forcing of either compression scheme. This will override
compiled-in defaults. jffs2_compress is reworked a bit, as the lzo/zlib
override shares lots of code w/ the PRIORITY mode.
Signed-off-by: Andres Salomon <dilinger@...ued.net>
---
fs/jffs2/compr.c | 119 ++++++++++++++++++++++++++++++++++++++----------------
fs/jffs2/compr.h | 2 +
fs/jffs2/super.c | 18 +++++++-
3 files changed, 102 insertions(+), 37 deletions(-)
diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c
index 97bc74d..5b6c9d1 100644
--- a/fs/jffs2/compr.c
+++ b/fs/jffs2/compr.c
@@ -53,6 +53,78 @@ static int jffs2_is_best_compression(struct jffs2_compressor *this,
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) {
+ printk(KERN_WARNING "JFFS2: 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
@@ -91,37 +163,8 @@ uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
case JFFS2_COMPR_MODE_NONE:
break;
case JFFS2_COMPR_MODE_PRIORITY:
- output_buf = kmalloc(*cdatalen,GFP_KERNEL);
- if (!output_buf) {
- printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
- goto out;
- }
- 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;
-
- this->usecount++;
- spin_unlock(&jffs2_compressor_list_lock);
- *datalen = orig_slen;
- *cdatalen = orig_dlen;
- compr_ret = this->compress(data_in, output_buf, datalen, cdatalen);
- spin_lock(&jffs2_compressor_list_lock);
- this->usecount--;
- if (!compr_ret) {
- 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);
+ ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
+ cdatalen);
break;
case JFFS2_COMPR_MODE_SIZE:
case JFFS2_COMPR_MODE_FAVOURLZO:
@@ -179,22 +222,28 @@ uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
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:
printk(KERN_ERR "JFFS2: unknown compression mode.\n");
}
- out:
+
if (ret == JFFS2_COMPR_NONE) {
*cpage_out = data_in;
*datalen = *cdatalen;
none_stat_compr_blocks++;
none_stat_compr_size += *datalen;
}
- else {
- *cpage_out = output_buf;
- }
return ret;
}
diff --git a/fs/jffs2/compr.h b/fs/jffs2/compr.h
index 13bb759..5e91d57 100644
--- a/fs/jffs2/compr.h
+++ b/fs/jffs2/compr.h
@@ -40,6 +40,8 @@
#define JFFS2_COMPR_MODE_PRIORITY 1
#define JFFS2_COMPR_MODE_SIZE 2
#define JFFS2_COMPR_MODE_FAVOURLZO 3
+#define JFFS2_COMPR_MODE_FORCELZO 4
+#define JFFS2_COMPR_MODE_FORCEZLIB 5
#define FAVOUR_LZO_PERCENT 80
diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
index bf40d3e..26366db 100644
--- a/fs/jffs2/super.c
+++ b/fs/jffs2/super.c
@@ -171,11 +171,25 @@ static int jffs2_parse_options(struct jffs2_sb_info *c, char *data)
if (!name)
return -ENOMEM;
- if (!strcmp(name, "none")) {
+ if (!strcmp(name, "none"))
c->mount_opts.compr = JFFS2_COMPR_MODE_NONE;
- c->mount_opts.override_compr = true;
+#ifdef CONFIG_JFFS2_LZO
+ else if (!strcmp(name, "lzo"))
+ c->mount_opts.compr = JFFS2_COMPR_MODE_FORCELZO;
+#endif
+#ifdef CONFIG_JFFS2_ZLIB
+ else if (!strcmp(name, "zlib"))
+ c->mount_opts.compr =
+ JFFS2_COMPR_MODE_FORCEZLIB;
+#endif
+ else {
+ printk(KERN_ERR "JFFS2 Error: unknown compressor \"%s\"",
+ name);
+ kfree(name);
+ return -EINVAL;
}
kfree(name);
+ c->mount_opts.override_compr = true;
break;
default:
printk(KERN_ERR "JFFS2 Error: unrecognized mount option '%s' or missing value\n",
--
1.7.2.5
--
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