diff options
Diffstat (limited to 'fs/jffs2/compr_zlib.c')
| -rw-r--r-- | fs/jffs2/compr_zlib.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/fs/jffs2/compr_zlib.c b/fs/jffs2/compr_zlib.c new file mode 100644 index 0000000..9f9932c --- /dev/null +++ b/fs/jffs2/compr_zlib.c @@ -0,0 +1,218 @@ +/* + * JFFS2 -- Journalling Flash File System, Version 2. + * + * Copyright (C) 2001-2003 Red Hat, Inc. + * + * Created by David Woodhouse <dwmw2@infradead.org> + * + * For licensing information, see the file 'LICENCE' in this directory. + * + * $Id: compr_zlib.c,v 1.29 2004/11/16 20:36:11 dwmw2 Exp $ + * + */ + +#if !defined(__KERNEL__) && !defined(__ECOS) +#error "The userspace support got too messy and was removed. Update your mkfs.jffs2" +#endif + +#include <linux/config.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/zlib.h> +#include <linux/zutil.h> +#include <asm/semaphore.h> +#include "nodelist.h" +#include "compr.h" + + /* Plan: call deflate() with avail_in == *sourcelen, + avail_out = *dstlen - 12 and flush == Z_FINISH. + If it doesn't manage to finish, call it again with + avail_in == 0 and avail_out set to the remaining 12 + bytes for it to clean up. + Q: Is 12 bytes sufficient? + */ +#define STREAM_END_SPACE 12 + +static DECLARE_MUTEX(deflate_sem); +static DECLARE_MUTEX(inflate_sem); +static z_stream inf_strm, def_strm; + +#ifdef __KERNEL__ /* Linux-only */ +#include <linux/vmalloc.h> +#include <linux/init.h> + +static int __init alloc_workspaces(void) +{ + def_strm.workspace = vmalloc(zlib_deflate_workspacesize()); + if (!def_strm.workspace) { + printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize()); + return -ENOMEM; + } + D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize())); + inf_strm.workspace = vmalloc(zlib_inflate_workspacesize()); + if (!inf_strm.workspace) { + printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize()); + vfree(def_strm.workspace); + return -ENOMEM; + } + D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize())); + return 0; +} + +static void free_workspaces(void) +{ + vfree(def_strm.workspace); + vfree(inf_strm.workspace); +} +#else +#define alloc_workspaces() (0) +#define free_workspaces() do { } while(0) +#endif /* __KERNEL__ */ + +int jffs2_zlib_compress(unsigned char *data_in, unsigned char *cpage_out, + uint32_t *sourcelen, uint32_t *dstlen, void *model) +{ + int ret; + + if (*dstlen <= STREAM_END_SPACE) + return -1; + + down(&deflate_sem); + + if (Z_OK != zlib_deflateInit(&def_strm, 3)) { + printk(KERN_WARNING "deflateInit failed\n"); + up(&deflate_sem); + return -1; + } + + def_strm.next_in = data_in; + def_strm.total_in = 0; + + def_strm.next_out = cpage_out; + def_strm.total_out = 0; + + while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) { + def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE); + def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out); + D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n", + def_strm.avail_in, def_strm.avail_out)); + ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH); + D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n", + def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out)); + if (ret != Z_OK) { + D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret)); + zlib_deflateEnd(&def_strm); + up(&deflate_sem); + return -1; + } + } + def_strm.avail_out += STREAM_END_SPACE; + def_strm.avail_in = 0; + ret = zlib_deflate(&def_strm, Z_FINISH); + zlib_deflateEnd(&def_strm); + + if (ret != Z_STREAM_END) { + D1(printk(KERN_DEBUG "final deflate returned %d\n", ret)); + ret = -1; + goto out; + } + + if (def_strm.total_out >= def_strm.total_in) { + D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n", + def_strm.total_in, def_strm.total_out)); + ret = -1; + goto out; + } + + D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n", + def_strm.total_in, def_strm.total_out)); + + *dstlen = def_strm.total_out; + *sourcelen = def_strm.total_in; + ret = 0; + out: + up(&deflate_sem); + return ret; +} + +int jffs2_zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, + uint32_t srclen, uint32_t destlen, void *model) +{ + int ret; + int wbits = MAX_WBITS; + + down(&inflate_sem); + + inf_strm.next_in = data_in; + inf_strm.avail_in = srclen; + inf_strm.total_in = 0; + + inf_strm.next_out = cpage_out; + inf_strm.avail_out = destlen; + inf_strm.total_out = 0; + + /* If it's deflate, and it's got no preset dictionary, then + we can tell zlib to skip the adler32 check. */ + if (srclen > 2 && !(data_in[1] & PRESET_DICT) && + ((data_in[0] & 0x0f) == Z_DEFLATED) && + !(((data_in[0]<<8) + data_in[1]) % 31)) { + + D2(printk(KERN_DEBUG "inflate skipping adler32\n")); + wbits = -((data_in[0] >> 4) + 8); + inf_strm.next_in += 2; + inf_strm.avail_in -= 2; + } else { + /* Let this remain D1 for now -- it should never happen */ + D1(printk(KERN_DEBUG "inflate not skipping adler32\n")); + } + + + if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) { + printk(KERN_WARNING "inflateInit failed\n"); + up(&inflate_sem); + return 1; + } + + while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK) + ; + if (ret != Z_STREAM_END) { + printk(KERN_NOTICE "inflate returned %d\n", ret); + } + zlib_inflateEnd(&inf_strm); + up(&inflate_sem); + return 0; +} + +static struct jffs2_compressor jffs2_zlib_comp = { + .priority = JFFS2_ZLIB_PRIORITY, + .name = "zlib", + .compr = JFFS2_COMPR_ZLIB, + .compress = &jffs2_zlib_compress, + .decompress = &jffs2_zlib_decompress, +#ifdef JFFS2_ZLIB_DISABLED + .disabled = 1, +#else + .disabled = 0, +#endif +}; + +int __init jffs2_zlib_init(void) +{ + int ret; + + ret = alloc_workspaces(); + if (ret) + return ret; + + ret = jffs2_register_compressor(&jffs2_zlib_comp); + if (ret) + free_workspaces(); + + return ret; +} + +void jffs2_zlib_exit(void) +{ + jffs2_unregister_compressor(&jffs2_zlib_comp); + free_workspaces(); +} |
