From 123005f3ccfa58637ad6e1a8b9f7f3f861ca65f4 Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Sun, 16 Oct 2011 18:15:23 -0700 Subject: 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. v2: update show_options accordingly. Signed-off-by: Andres Salomon Signed-off-by: Artem Bityutskiy --- fs/jffs2/compr.c | 119 +++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 84 insertions(+), 35 deletions(-) (limited to 'fs/jffs2/compr.c') diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c index 97bc74db2c96..5b6c9d1a2fb9 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; } -- cgit v1.2.3